[DLM] The core of the DLM for GFS2/CLVM

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.

It implements VAX-style locking modes.

Signed-off-by: David Teigland <[e-mail]>
Signed-off-by: Steve Whitehouse <[e-mail]>

fs/Kconfig

···
 endmenu
 
 source "fs/nls/Kconfig"
+source "fs/dlm/Kconfig"
 
 endmenu
 

fs/Makefile

···
 obj-y				+= devpts/
 
 obj-$(CONFIG_PROFILING)		+= dcookies.o
+obj-$(CONFIG_DLM)		+= dlm/
  
 # Do not add any filesystems before this line
 obj-$(CONFIG_REISERFS_FS)	+= reiserfs/

fs/dlm/Kconfig

···
+menu "Distributed Lock Manager"
+	depends on INET && EXPERIMENTAL
+
+config DLM
+	tristate "Distributed Lock Manager (DLM)"
+	depends on SYSFS
+	depends on IPV6 || IPV6=n
+	select IP_SCTP
+	select CONFIGFS_FS
+	help
+	A general purpose distributed lock manager for kernel or userspace
+	applications.
+
+config DLM_DEVICE
+	tristate "DLM device for userspace access"
+	depends on DLM
+	help
+	This module creates a misc device through which the dlm lockspace
+	and locking functions become available to userspace applications
+	(usually through the libdlm library).
+
+config DLM_DEBUG
+	bool "DLM debugging"
+	depends on DLM
+	help
+	Under the debugfs mount point, the name of each lockspace will
+	appear as a file in the "dlm" directory.  The output is the
+	list of resource and locks the local node knows about.
+
+endmenu

fs/dlm/Makefile

···
+obj-$(CONFIG_DLM) +=		dlm.o
+obj-$(CONFIG_DLM_DEVICE) +=	dlm_device.o
+
+dlm-y :=			ast.o \
+				config.o \
+				dir.o \
+				lock.o \
+				lockspace.o \
+				lowcomms.o \
+				main.o \
+				member.o \
+				memory.o \
+				midcomms.o \
+				rcom.o \
+				recover.o \
+				recoverd.o \
+				requestqueue.o \
+				util.o
+dlm-$(CONFIG_DLM_DEBUG) +=	debug_fs.o
+
+dlm_device-y :=			device.o

fs/dlm/ast.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lock.h"
+#include "ast.h"
+
+#define WAKE_ASTS  0
+
+static struct list_head		ast_queue;
+static spinlock_t		ast_queue_lock;
+static struct task_struct *	astd_task;
+static unsigned long		astd_wakeflags;
+static struct semaphore		astd_running;
+
+
+void dlm_del_ast(struct dlm_lkb *lkb)
+{
+	spin_lock(&ast_queue_lock);
+	if (lkb->lkb_ast_type & (AST_COMP | AST_BAST))
+		list_del(&lkb->lkb_astqueue);
+	spin_unlock(&ast_queue_lock);
+}
+
+void dlm_add_ast(struct dlm_lkb *lkb, int type)
+{
+	spin_lock(&ast_queue_lock);
+	if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) {
+		kref_get(&lkb->lkb_ref);
+		list_add_tail(&lkb->lkb_astqueue, &ast_queue);
+	}
+	lkb->lkb_ast_type |= type;
+	spin_unlock(&ast_queue_lock);
+
+	set_bit(WAKE_ASTS, &astd_wakeflags);
+	wake_up_process(astd_task);
+}
+
+static void process_asts(void)
+{
+	struct dlm_ls *ls = NULL;
+	struct dlm_rsb *r = NULL;
+	struct dlm_lkb *lkb;
+	void (*cast) (long param);
+	void (*bast) (long param, int mode);
+	int type = 0, found, bmode;
+
+	for (;;) {
+		found = FALSE;
+		spin_lock(&ast_queue_lock);
+		list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
+			r = lkb->lkb_resource;
+			ls = r->res_ls;
+
+			if (dlm_locking_stopped(ls))
+				continue;
+
+			list_del(&lkb->lkb_astqueue);
+			type = lkb->lkb_ast_type;
+			lkb->lkb_ast_type = 0;
+			found = TRUE;
+			break;
+		}
+		spin_unlock(&ast_queue_lock);
+
+		if (!found)
+			break;
+
+		cast = lkb->lkb_astaddr;
+		bast = lkb->lkb_bastaddr;
+		bmode = lkb->lkb_bastmode;
+
+		if ((type & AST_COMP) && cast)
+			cast(lkb->lkb_astparam);
+
+		/* FIXME: Is it safe to look at lkb_grmode here
+		   without doing a lock_rsb() ?
+		   Look at other checks in v1 to avoid basts. */
+
+		if ((type & AST_BAST) && bast)
+			if (!dlm_modes_compat(lkb->lkb_grmode, bmode))
+				bast(lkb->lkb_astparam, bmode);
+
+		/* this removes the reference added by dlm_add_ast
+		   and may result in the lkb being freed */
+		dlm_put_lkb(lkb);
+
+		schedule();
+	}
+}
+
+static inline int no_asts(void)
+{
+	int ret;
+
+	spin_lock(&ast_queue_lock);
+	ret = list_empty(&ast_queue);
+	spin_unlock(&ast_queue_lock);
+	return ret;
+}
+
+static int dlm_astd(void *data)
+{
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (!test_bit(WAKE_ASTS, &astd_wakeflags))
+			schedule();
+		set_current_state(TASK_RUNNING);
+
+		down(&astd_running);
+		if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
+			process_asts();
+		up(&astd_running);
+	}
+	return 0;
+}
+
+void dlm_astd_wake(void)
+{
+	if (!no_asts()) {
+		set_bit(WAKE_ASTS, &astd_wakeflags);
+		wake_up_process(astd_task);
+	}
+}
+
+int dlm_astd_start(void)
+{
+	struct task_struct *p;
+	int error = 0;
+
+	INIT_LIST_HEAD(&ast_queue);
+	spin_lock_init(&ast_queue_lock);
+	init_MUTEX(&astd_running);
+
+	p = kthread_run(dlm_astd, NULL, "dlm_astd");
+	if (IS_ERR(p))
+		error = PTR_ERR(p);
+	else
+		astd_task = p;
+	return error;
+}
+
+void dlm_astd_stop(void)
+{
+	kthread_stop(astd_task);
+}
+
+void dlm_astd_suspend(void)
+{
+	down(&astd_running);
+}
+
+void dlm_astd_resume(void)
+{
+	up(&astd_running);
+}
+

fs/dlm/ast.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __ASTD_DOT_H__
+#define __ASTD_DOT_H__
+
+void dlm_add_ast(struct dlm_lkb *lkb, int type);
+void dlm_del_ast(struct dlm_lkb *lkb);
+
+void dlm_astd_wake(void);
+int dlm_astd_start(void);
+void dlm_astd_stop(void);
+void dlm_astd_suspend(void);
+void dlm_astd_resume(void);
+
+#endif
+

fs/dlm/config.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/configfs.h>
+#include <net/sock.h>
+
+#include "config.h"
+
+/*
+ * /config/dlm/<cluster>/spaces/<space>/nodes/<node>/nodeid
+ * /config/dlm/<cluster>/spaces/<space>/nodes/<node>/weight
+ * /config/dlm/<cluster>/comms/<comm>/nodeid
+ * /config/dlm/<cluster>/comms/<comm>/local
+ * /config/dlm/<cluster>/comms/<comm>/addr
+ * The <cluster> level is useless, but I haven't figured out how to avoid it.
+ */
+
+static struct config_group *space_list;
+static struct config_group *comm_list;
+static struct comm *local_comm;
+
+struct clusters;
+struct cluster;
+struct spaces;
+struct space;
+struct comms;
+struct comm;
+struct nodes;
+struct node;
+
+static struct config_group *make_cluster(struct config_group *, const char *);
+static void drop_cluster(struct config_group *, struct config_item *);
+static void release_cluster(struct config_item *);
+static struct config_group *make_space(struct config_group *, const char *);
+static void drop_space(struct config_group *, struct config_item *);
+static void release_space(struct config_item *);
+static struct config_item *make_comm(struct config_group *, const char *);
+static void drop_comm(struct config_group *, struct config_item *);
+static void release_comm(struct config_item *);
+static struct config_item *make_node(struct config_group *, const char *);
+static void drop_node(struct config_group *, struct config_item *);
+static void release_node(struct config_item *);
+
+static ssize_t show_comm(struct config_item *i, struct configfs_attribute *a,
+			 char *buf);
+static ssize_t store_comm(struct config_item *i, struct configfs_attribute *a,
+			  const char *buf, size_t len);
+static ssize_t show_node(struct config_item *i, struct configfs_attribute *a,
+			 char *buf);
+static ssize_t store_node(struct config_item *i, struct configfs_attribute *a,
+			  const char *buf, size_t len);
+
+static ssize_t comm_nodeid_read(struct comm *cm, char *buf);
+static ssize_t comm_nodeid_write(struct comm *cm, const char *buf, size_t len);
+static ssize_t comm_local_read(struct comm *cm, char *buf);
+static ssize_t comm_local_write(struct comm *cm, const char *buf, size_t len);
+static ssize_t comm_addr_write(struct comm *cm, const char *buf, size_t len);
+static ssize_t node_nodeid_read(struct node *nd, char *buf);
+static ssize_t node_nodeid_write(struct node *nd, const char *buf, size_t len);
+static ssize_t node_weight_read(struct node *nd, char *buf);
+static ssize_t node_weight_write(struct node *nd, const char *buf, size_t len);
+
+enum {
+	COMM_ATTR_NODEID = 0,
+	COMM_ATTR_LOCAL,
+	COMM_ATTR_ADDR,
+};
+
+struct comm_attribute {
+	struct configfs_attribute attr;
+	ssize_t (*show)(struct comm *, char *);
+	ssize_t (*store)(struct comm *, const char *, size_t);
+};
+
+static struct comm_attribute comm_attr_nodeid = {
+	.attr   = { .ca_owner = THIS_MODULE,
+                    .ca_name = "nodeid",
+                    .ca_mode = S_IRUGO | S_IWUSR },
+	.show   = comm_nodeid_read,
+	.store  = comm_nodeid_write,
+};
+
+static struct comm_attribute comm_attr_local = {
+	.attr   = { .ca_owner = THIS_MODULE,
+                    .ca_name = "local",
+                    .ca_mode = S_IRUGO | S_IWUSR },
+	.show   = comm_local_read,
+	.store  = comm_local_write,
+};
+
+static struct comm_attribute comm_attr_addr = {
+	.attr   = { .ca_owner = THIS_MODULE,
+                    .ca_name = "addr",
+                    .ca_mode = S_IRUGO | S_IWUSR },
+	.store  = comm_addr_write,
+};
+
+static struct configfs_attribute *comm_attrs[] = {
+	[COMM_ATTR_NODEID] = &comm_attr_nodeid.attr,
+	[COMM_ATTR_LOCAL] = &comm_attr_local.attr,
+	[COMM_ATTR_ADDR] = &comm_attr_addr.attr,
+	NULL,
+};
+
+enum {
+	NODE_ATTR_NODEID = 0,
+	NODE_ATTR_WEIGHT,
+};
+
+struct node_attribute {
+	struct configfs_attribute attr;
+	ssize_t (*show)(struct node *, char *);
+	ssize_t (*store)(struct node *, const char *, size_t);
+};
+
+static struct node_attribute node_attr_nodeid = {
+	.attr   = { .ca_owner = THIS_MODULE,
+                    .ca_name = "nodeid",
+                    .ca_mode = S_IRUGO | S_IWUSR },
+	.show   = node_nodeid_read,
+	.store  = node_nodeid_write,
+};
+
+static struct node_attribute node_attr_weight = {
+	.attr   = { .ca_owner = THIS_MODULE,
+                    .ca_name = "weight",
+                    .ca_mode = S_IRUGO | S_IWUSR },
+	.show   = node_weight_read,
+	.store  = node_weight_write,
+};
+
+static struct configfs_attribute *node_attrs[] = {
+	[NODE_ATTR_NODEID] = &node_attr_nodeid.attr,
+	[NODE_ATTR_WEIGHT] = &node_attr_weight.attr,
+	NULL,
+};
+
+struct clusters {
+	struct configfs_subsystem subsys;
+};
+
+struct cluster {
+	struct config_group group;
+};
+
+struct spaces {
+	struct config_group ss_group;
+};
+
+struct space {
+	struct config_group group;
+	struct list_head members;
+	struct semaphore members_lock;
+	int members_count;
+};
+
+struct comms {
+	struct config_group cs_group;
+};
+
+struct comm {
+	struct config_item item;
+	int nodeid;
+	int local;
+	int addr_count;
+	struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
+};
+
+struct nodes {
+	struct config_group ns_group;
+};
+
+struct node {
+	struct config_item item;
+	struct list_head list; /* space->members */
+	int nodeid;
+	int weight;
+};
+
+static struct configfs_group_operations clusters_ops = {
+	.make_group = make_cluster,
+	.drop_item = drop_cluster,
+};
+
+static struct configfs_item_operations cluster_ops = {
+	.release = release_cluster,
+};
+
+static struct configfs_group_operations spaces_ops = {
+	.make_group = make_space,
+	.drop_item = drop_space,
+};
+
+static struct configfs_item_operations space_ops = {
+	.release = release_space,
+};
+
+static struct configfs_group_operations comms_ops = {
+	.make_item = make_comm,
+	.drop_item = drop_comm,
+};
+
+static struct configfs_item_operations comm_ops = {
+	.release = release_comm,
+	.show_attribute = show_comm,
+	.store_attribute = store_comm,
+};
+
+static struct configfs_group_operations nodes_ops = {
+	.make_item = make_node,
+	.drop_item = drop_node,
+};
+
+static struct configfs_item_operations node_ops = {
+	.release = release_node,
+	.show_attribute = show_node,
+	.store_attribute = store_node,
+};
+
+static struct config_item_type clusters_type = {
+	.ct_group_ops = &clusters_ops,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type cluster_type = {
+	.ct_item_ops = &cluster_ops,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type spaces_type = {
+	.ct_group_ops = &spaces_ops,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type space_type = {
+	.ct_item_ops = &space_ops,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type comms_type = {
+	.ct_group_ops = &comms_ops,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type comm_type = {
+	.ct_item_ops = &comm_ops,
+	.ct_attrs = comm_attrs,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type nodes_type = {
+	.ct_group_ops = &nodes_ops,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_item_type node_type = {
+	.ct_item_ops = &node_ops,
+	.ct_attrs = node_attrs,
+	.ct_owner = THIS_MODULE,
+};
+
+static struct cluster *to_cluster(struct config_item *i)
+{
+	return i ? container_of(to_config_group(i), struct cluster, group):NULL;
+}
+
+static struct space *to_space(struct config_item *i)
+{
+	return i ? container_of(to_config_group(i), struct space, group) : NULL;
+}
+
+static struct comm *to_comm(struct config_item *i)
+{
+	return i ? container_of(i, struct comm, item) : NULL;
+}
+
+static struct node *to_node(struct config_item *i)
+{
+	return i ? container_of(i, struct node, item) : NULL;
+}
+
+static struct config_group *make_cluster(struct config_group *g,
+					 const char *name)
+{
+	struct cluster *cl = NULL;
+	struct spaces *sps = NULL;
+	struct comms *cms = NULL;
+	void *gps = NULL;
+
+	cl = kzalloc(sizeof(struct cluster), GFP_KERNEL);
+	gps = kcalloc(3, sizeof(struct config_group *), GFP_KERNEL);
+	sps = kzalloc(sizeof(struct spaces), GFP_KERNEL);
+	cms = kzalloc(sizeof(struct comms), GFP_KERNEL);
+
+	if (!cl || !gps || !sps || !cms)
+		goto fail;
+
+	config_group_init_type_name(&cl->group, name, &cluster_type);
+	config_group_init_type_name(&sps->ss_group, "spaces", &spaces_type);
+	config_group_init_type_name(&cms->cs_group, "comms", &comms_type);
+
+	cl->group.default_groups = gps;
+	cl->group.default_groups[0] = &sps->ss_group;
+	cl->group.default_groups[1] = &cms->cs_group;
+	cl->group.default_groups[2] = NULL;
+
+	space_list = &sps->ss_group;
+	comm_list = &cms->cs_group;
+	return &cl->group;
+
+ fail:
+	kfree(cl);
+	kfree(gps);
+	kfree(sps);
+	kfree(cms);
+	return NULL;
+}
+
+static void drop_cluster(struct config_group *g, struct config_item *i)
+{
+	struct cluster *cl = to_cluster(i);
+	struct config_item *tmp;
+	int j;
+
+	for (j = 0; cl->group.default_groups[j]; j++) {
+		tmp = &cl->group.default_groups[j]->cg_item;
+		cl->group.default_groups[j] = NULL;
+		config_item_put(tmp);
+	}
+
+	space_list = NULL;
+	comm_list = NULL;
+
+	config_item_put(i);
+}
+
+static void release_cluster(struct config_item *i)
+{
+	struct cluster *cl = to_cluster(i);
+	kfree(cl->group.default_groups);
+	kfree(cl);
+}
+
+static struct config_group *make_space(struct config_group *g, const char *name)
+{
+	struct space *sp = NULL;
+	struct nodes *nds = NULL;
+	void *gps = NULL;
+
+	sp = kzalloc(sizeof(struct space), GFP_KERNEL);
+	gps = kcalloc(2, sizeof(struct config_group *), GFP_KERNEL);
+	nds = kzalloc(sizeof(struct nodes), GFP_KERNEL);
+
+	if (!sp || !gps || !nds)
+		goto fail;
+
+	config_group_init_type_name(&sp->group, name, &space_type);
+	config_group_init_type_name(&nds->ns_group, "nodes", &nodes_type);
+
+	sp->group.default_groups = gps;
+	sp->group.default_groups[0] = &nds->ns_group;
+	sp->group.default_groups[1] = NULL;
+
+	INIT_LIST_HEAD(&sp->members);
+	init_MUTEX(&sp->members_lock);
+	sp->members_count = 0;
+	return &sp->group;
+
+ fail:
+	kfree(sp);
+	kfree(gps);
+	kfree(nds);
+	return NULL;
+}
+
+static void drop_space(struct config_group *g, struct config_item *i)
+{
+	struct space *sp = to_space(i);
+	struct config_item *tmp;
+	int j;
+
+	/* assert list_empty(&sp->members) */
+
+	for (j = 0; sp->group.default_groups[j]; j++) {
+		tmp = &sp->group.default_groups[j]->cg_item;
+		sp->group.default_groups[j] = NULL;
+		config_item_put(tmp);
+	}
+
+	config_item_put(i);
+}
+
+static void release_space(struct config_item *i)
+{
+	struct space *sp = to_space(i);
+	kfree(sp->group.default_groups);
+	kfree(sp);
+}
+
+static struct config_item *make_comm(struct config_group *g, const char *name)
+{
+	struct comm *cm;
+
+	cm = kzalloc(sizeof(struct comm), GFP_KERNEL);
+	if (!cm)
+		return NULL;
+
+	config_item_init_type_name(&cm->item, name, &comm_type);
+	cm->nodeid = -1;
+	cm->local = 0;
+	cm->addr_count = 0;
+	return &cm->item;
+}
+
+static void drop_comm(struct config_group *g, struct config_item *i)
+{
+	struct comm *cm = to_comm(i);
+	if (local_comm == cm)
+		local_comm = NULL;
+	while (cm->addr_count--)
+		kfree(cm->addr[cm->addr_count]);
+	config_item_put(i);
+}
+
+static void release_comm(struct config_item *i)
+{
+	struct comm *cm = to_comm(i);
+	kfree(cm);
+}
+
+static struct config_item *make_node(struct config_group *g, const char *name)
+{
+	struct space *sp = to_space(g->cg_item.ci_parent);
+	struct node *nd;
+
+	nd = kzalloc(sizeof(struct node), GFP_KERNEL);
+	if (!nd)
+		return NULL;
+
+	config_item_init_type_name(&nd->item, name, &node_type);
+	nd->nodeid = -1;
+	nd->weight = 1;  /* default weight of 1 if none is set */
+
+	down(&sp->members_lock);
+	list_add(&nd->list, &sp->members);
+	sp->members_count++;
+	up(&sp->members_lock);
+
+	return &nd->item;
+}
+
+static void drop_node(struct config_group *g, struct config_item *i)
+{
+	struct space *sp = to_space(g->cg_item.ci_parent);
+	struct node *nd = to_node(i);
+
+	down(&sp->members_lock);
+	list_del(&nd->list);
+	sp->members_count--;
+	up(&sp->members_lock);
+
+	config_item_put(i);
+}
+
+static void release_node(struct config_item *i)
+{
+	struct node *nd = to_node(i);
+	kfree(nd);
+}
+
+static struct clusters clusters_root = {
+	.subsys = {
+		.su_group = {
+			.cg_item = {
+				.ci_namebuf = "dlm",
+				.ci_type = &clusters_type,
+			},
+		},
+	},
+};
+
+int dlm_config_init(void)
+{
+	config_group_init(&clusters_root.subsys.su_group);
+	init_MUTEX(&clusters_root.subsys.su_sem);
+	return configfs_register_subsystem(&clusters_root.subsys);
+}
+
+void dlm_config_exit(void)
+{
+	configfs_unregister_subsystem(&clusters_root.subsys);
+}
+
+/*
+ * Functions for user space to read/write attributes
+ */
+
+static ssize_t show_comm(struct config_item *i, struct configfs_attribute *a,
+			 char *buf)
+{
+	struct comm *cm = to_comm(i);
+	struct comm_attribute *cma =
+			container_of(a, struct comm_attribute, attr);
+	return cma->show ? cma->show(cm, buf) : 0;
+}
+
+static ssize_t store_comm(struct config_item *i, struct configfs_attribute *a,
+			  const char *buf, size_t len)
+{
+	struct comm *cm = to_comm(i);
+	struct comm_attribute *cma =
+		container_of(a, struct comm_attribute, attr);
+	return cma->store ? cma->store(cm, buf, len) : -EINVAL;
+}
+
+static ssize_t comm_nodeid_read(struct comm *cm, char *buf)
+{
+	return sprintf(buf, "%d\n", cm->nodeid);
+}
+
+static ssize_t comm_nodeid_write(struct comm *cm, const char *buf, size_t len)
+{
+	cm->nodeid = simple_strtol(buf, NULL, 0);
+	return len;
+}
+
+static ssize_t comm_local_read(struct comm *cm, char *buf)
+{
+	return sprintf(buf, "%d\n", cm->local);
+}
+
+static ssize_t comm_local_write(struct comm *cm, const char *buf, size_t len)
+{
+	cm->local= simple_strtol(buf, NULL, 0);
+	if (cm->local && !local_comm)
+		local_comm = cm;
+	return len;
+}
+
+static ssize_t comm_addr_write(struct comm *cm, const char *buf, size_t len)
+{
+	struct sockaddr_storage *addr;
+
+	if (len != sizeof(struct sockaddr_storage))
+		return -EINVAL;
+
+	if (cm->addr_count >= DLM_MAX_ADDR_COUNT)
+		return -ENOSPC;
+
+	addr = kzalloc(sizeof(*addr), GFP_KERNEL);
+	if (!addr)
+		return -ENOMEM;
+
+	memcpy(addr, buf, len);
+	cm->addr[cm->addr_count++] = addr;
+	return len;
+}
+
+static ssize_t show_node(struct config_item *i, struct configfs_attribute *a,
+			 char *buf)
+{
+	struct node *nd = to_node(i);
+	struct node_attribute *nda =
+			container_of(a, struct node_attribute, attr);
+	return nda->show ? nda->show(nd, buf) : 0;
+}
+
+static ssize_t store_node(struct config_item *i, struct configfs_attribute *a,
+			  const char *buf, size_t len)
+{
+	struct node *nd = to_node(i);
+	struct node_attribute *nda =
+		container_of(a, struct node_attribute, attr);
+	return nda->store ? nda->store(nd, buf, len) : -EINVAL;
+}
+
+static ssize_t node_nodeid_read(struct node *nd, char *buf)
+{
+	return sprintf(buf, "%d\n", nd->nodeid);
+}
+
+static ssize_t node_nodeid_write(struct node *nd, const char *buf, size_t len)
+{
+	nd->nodeid = simple_strtol(buf, NULL, 0);
+	return len;
+}
+
+static ssize_t node_weight_read(struct node *nd, char *buf)
+{
+	return sprintf(buf, "%d\n", nd->weight);
+}
+
+static ssize_t node_weight_write(struct node *nd, const char *buf, size_t len)
+{
+	nd->weight = simple_strtol(buf, NULL, 0);
+	return len;
+}
+
+/*
+ * Functions for the dlm to get the info that's been configured
+ */
+
+static struct space *get_space(char *name)
+{
+	if (!space_list)
+		return NULL;
+	return to_space(config_group_find_obj(space_list, name));
+}
+
+static void put_space(struct space *sp)
+{
+	config_item_put(&sp->group.cg_item);
+}
+
+static struct comm *get_comm(int nodeid, struct sockaddr_storage *addr)
+{
+	struct config_item *i;
+	struct comm *cm = NULL;
+	int found = 0;
+
+	if (!comm_list)
+		return NULL;
+
+	down(&clusters_root.subsys.su_sem);
+
+	list_for_each_entry(i, &comm_list->cg_children, ci_entry) {
+		cm = to_comm(i);
+
+		if (nodeid) {
+			if (cm->nodeid != nodeid)
+				continue;
+			found = 1;
+			break;
+		} else {
+			if (!cm->addr_count ||
+			    memcmp(cm->addr[0], addr, sizeof(*addr)))
+				continue;
+			found = 1;
+			break;
+		}
+	}
+	up(&clusters_root.subsys.su_sem);
+
+	if (found)
+		config_item_get(i);
+	else
+		cm = NULL;
+	return cm;
+}
+
+static void put_comm(struct comm *cm)
+{
+	config_item_put(&cm->item);
+}
+
+/* caller must free mem */
+int dlm_nodeid_list(char *lsname, int **ids_out)
+{
+	struct space *sp;
+	struct node *nd;
+	int i = 0, rv = 0;
+	int *ids;
+
+	sp = get_space(lsname);
+	if (!sp)
+		return -EEXIST;
+
+	down(&sp->members_lock);
+	if (!sp->members_count) {
+		rv = 0;
+		goto out;
+	}
+
+	ids = kcalloc(sp->members_count, sizeof(int), GFP_KERNEL);
+	if (!ids) {
+		rv = -ENOMEM;
+		goto out;
+	}
+
+	rv = sp->members_count;
+	list_for_each_entry(nd, &sp->members, list)
+		ids[i++] = nd->nodeid;
+
+	if (rv != i)
+		printk("bad nodeid count %d %d\n", rv, i);
+
+	*ids_out = ids;
+ out:
+	up(&sp->members_lock);
+	put_space(sp);
+	return rv;
+}
+
+int dlm_node_weight(char *lsname, int nodeid)
+{
+	struct space *sp;
+	struct node *nd;
+	int w = -EEXIST;
+
+	sp = get_space(lsname);
+	if (!sp)
+		goto out;
+
+	down(&sp->members_lock);
+	list_for_each_entry(nd, &sp->members, list) {
+		if (nd->nodeid != nodeid)
+			continue;
+		w = nd->weight;
+		break;
+	}
+	up(&sp->members_lock);
+	put_space(sp);
+ out:
+	return w;
+}
+
+int dlm_nodeid_to_addr(int nodeid, struct sockaddr_storage *addr)
+{
+	struct comm *cm = get_comm(nodeid, NULL);
+	if (!cm)
+		return -EEXIST;
+	if (!cm->addr_count)
+		return -ENOENT;
+	memcpy(addr, cm->addr[0], sizeof(*addr));
+	put_comm(cm);
+	return 0;
+}
+
+int dlm_addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
+{
+	struct comm *cm = get_comm(0, addr);
+	if (!cm)
+		return -EEXIST;
+	*nodeid = cm->nodeid;
+	put_comm(cm);
+	return 0;
+}
+
+int dlm_our_nodeid(void)
+{
+	return local_comm ? local_comm->nodeid : 0;
+}
+
+/* num 0 is first addr, num 1 is second addr */
+int dlm_our_addr(struct sockaddr_storage *addr, int num)
+{
+	if (!local_comm)
+		return -1;
+	if (num + 1 > local_comm->addr_count)
+		return -1;
+	memcpy(addr, local_comm->addr[num], sizeof(*addr));
+	return 0;
+}
+
+/* Config file defaults */
+#define DEFAULT_TCP_PORT       21064
+#define DEFAULT_BUFFER_SIZE     4096
+#define DEFAULT_RSBTBL_SIZE      256
+#define DEFAULT_LKBTBL_SIZE     1024
+#define DEFAULT_DIRTBL_SIZE      512
+#define DEFAULT_RECOVER_TIMER      5
+#define DEFAULT_TOSS_SECS         10
+#define DEFAULT_SCAN_SECS          5
+
+struct dlm_config_info dlm_config = {
+	.tcp_port = DEFAULT_TCP_PORT,
+	.buffer_size = DEFAULT_BUFFER_SIZE,
+	.rsbtbl_size = DEFAULT_RSBTBL_SIZE,
+	.lkbtbl_size = DEFAULT_LKBTBL_SIZE,
+	.dirtbl_size = DEFAULT_DIRTBL_SIZE,
+	.recover_timer = DEFAULT_RECOVER_TIMER,
+	.toss_secs = DEFAULT_TOSS_SECS,
+	.scan_secs = DEFAULT_SCAN_SECS
+};
+

fs/dlm/config.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __CONFIG_DOT_H__
+#define __CONFIG_DOT_H__
+
+#define DLM_MAX_ADDR_COUNT 3
+
+struct dlm_config_info {
+	int tcp_port;
+	int buffer_size;
+	int rsbtbl_size;
+	int lkbtbl_size;
+	int dirtbl_size;
+	int recover_timer;
+	int toss_secs;
+	int scan_secs;
+};
+
+extern struct dlm_config_info dlm_config;
+
+int dlm_config_init(void);
+void dlm_config_exit(void);
+int dlm_node_weight(char *lsname, int nodeid);
+int dlm_nodeid_list(char *lsname, int **ids_out);
+int dlm_nodeid_to_addr(int nodeid, struct sockaddr_storage *addr);
+int dlm_addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid);
+int dlm_our_nodeid(void);
+int dlm_our_addr(struct sockaddr_storage *addr, int num);
+
+#endif				/* __CONFIG_DOT_H__ */
+

fs/dlm/debug_fs.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include <linux/pagemap.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/debugfs.h>
+
+#include "dlm_internal.h"
+
+
+static struct dentry *dlm_root;
+
+struct rsb_iter {
+	int entry;
+	struct dlm_ls *ls;
+	struct list_head *next;
+	struct dlm_rsb *rsb;
+};
+
+static char *print_lockmode(int mode)
+{
+	switch (mode) {
+	case DLM_LOCK_IV:
+		return "--";
+	case DLM_LOCK_NL:
+		return "NL";
+	case DLM_LOCK_CR:
+		return "CR";
+	case DLM_LOCK_CW:
+		return "CW";
+	case DLM_LOCK_PR:
+		return "PR";
+	case DLM_LOCK_PW:
+		return "PW";
+	case DLM_LOCK_EX:
+		return "EX";
+	default:
+		return "??";
+	}
+}
+
+static void print_lock(struct seq_file *s, struct dlm_lkb *lkb,
+		       struct dlm_rsb *res)
+{
+	seq_printf(s, "%08x %s", lkb->lkb_id, print_lockmode(lkb->lkb_grmode));
+
+	if (lkb->lkb_status == DLM_LKSTS_CONVERT
+	    || lkb->lkb_status == DLM_LKSTS_WAITING)
+		seq_printf(s, " (%s)", print_lockmode(lkb->lkb_rqmode));
+
+	if (lkb->lkb_range) {
+		/* FIXME: this warns on Alpha */
+		if (lkb->lkb_status == DLM_LKSTS_CONVERT
+		    || lkb->lkb_status == DLM_LKSTS_GRANTED)
+			seq_printf(s, " %" PRIx64 "-%" PRIx64,
+				   lkb->lkb_range[GR_RANGE_START],
+				   lkb->lkb_range[GR_RANGE_END]);
+		if (lkb->lkb_status == DLM_LKSTS_CONVERT
+		    || lkb->lkb_status == DLM_LKSTS_WAITING)
+			seq_printf(s, " (%" PRIx64 "-%" PRIx64 ")",
+				   lkb->lkb_range[RQ_RANGE_START],
+				   lkb->lkb_range[RQ_RANGE_END]);
+	}
+
+	if (lkb->lkb_nodeid) {
+		if (lkb->lkb_nodeid != res->res_nodeid)
+			seq_printf(s, " Remote: %3d %08x", lkb->lkb_nodeid,
+				   lkb->lkb_remid);
+		else
+			seq_printf(s, " Master:     %08x", lkb->lkb_remid);
+	}
+
+	if (lkb->lkb_wait_type)
+		seq_printf(s, " wait_type: %d", lkb->lkb_wait_type);
+
+	seq_printf(s, "\n");
+}
+
+static int print_resource(struct dlm_rsb *res, struct seq_file *s)
+{
+	struct dlm_lkb *lkb;
+	int i, lvblen = res->res_ls->ls_lvblen;
+
+	seq_printf(s, "\nResource %p Name (len=%d) \"", res, res->res_length);
+	for (i = 0; i < res->res_length; i++) {
+		if (isprint(res->res_name[i]))
+			seq_printf(s, "%c", res->res_name[i]);
+		else
+			seq_printf(s, "%c", '.');
+	}
+	if (res->res_nodeid > 0)
+		seq_printf(s, "\"  \nLocal Copy, Master is node %d\n",
+			   res->res_nodeid);
+	else if (res->res_nodeid == 0)
+		seq_printf(s, "\"  \nMaster Copy\n");
+	else if (res->res_nodeid == -1)
+		seq_printf(s, "\"  \nLooking up master (lkid %x)\n",
+			   res->res_first_lkid);
+	else
+		seq_printf(s, "\"  \nInvalid master %d\n", res->res_nodeid);
+
+	/* Print the LVB: */
+	if (res->res_lvbptr) {
+		seq_printf(s, "LVB: ");
+		for (i = 0; i < lvblen; i++) {
+			if (i == lvblen / 2)
+				seq_printf(s, "\n     ");
+			seq_printf(s, "%02x ",
+				   (unsigned char) res->res_lvbptr[i]);
+		}
+		if (rsb_flag(res, RSB_VALNOTVALID))
+			seq_printf(s, " (INVALID)");
+		seq_printf(s, "\n");
+	}
+
+	/* Print the locks attached to this resource */
+	seq_printf(s, "Granted Queue\n");
+	list_for_each_entry(lkb, &res->res_grantqueue, lkb_statequeue)
+		print_lock(s, lkb, res);
+
+	seq_printf(s, "Conversion Queue\n");
+	list_for_each_entry(lkb, &res->res_convertqueue, lkb_statequeue)
+		print_lock(s, lkb, res);
+
+	seq_printf(s, "Waiting Queue\n");
+	list_for_each_entry(lkb, &res->res_waitqueue, lkb_statequeue)
+		print_lock(s, lkb, res);
+
+	return 0;
+}
+
+static int rsb_iter_next(struct rsb_iter *ri)
+{
+	struct dlm_ls *ls = ri->ls;
+	int i;
+
+	if (!ri->next) {
+ top:
+		/* Find the next non-empty hash bucket */
+		for (i = ri->entry; i < ls->ls_rsbtbl_size; i++) {
+			read_lock(&ls->ls_rsbtbl[i].lock);
+			if (!list_empty(&ls->ls_rsbtbl[i].list)) {
+				ri->next = ls->ls_rsbtbl[i].list.next;
+				read_unlock(&ls->ls_rsbtbl[i].lock);
+				break;
+			}
+			read_unlock(&ls->ls_rsbtbl[i].lock);
+                }
+		ri->entry = i;
+
+		if (ri->entry >= ls->ls_rsbtbl_size)
+			return 1;
+	} else {
+		i = ri->entry;
+		read_lock(&ls->ls_rsbtbl[i].lock);
+		ri->next = ri->next->next;
+		if (ri->next->next == ls->ls_rsbtbl[i].list.next) {
+			/* End of list - move to next bucket */
+			ri->next = NULL;
+			ri->entry++;
+			read_unlock(&ls->ls_rsbtbl[i].lock);
+			goto top;
+                }
+		read_unlock(&ls->ls_rsbtbl[i].lock);
+	}
+	ri->rsb = list_entry(ri->next, struct dlm_rsb, res_hashchain);
+
+	return 0;
+}
+
+static void rsb_iter_free(struct rsb_iter *ri)
+{
+	kfree(ri);
+}
+
+static struct rsb_iter *rsb_iter_init(struct dlm_ls *ls)
+{
+	struct rsb_iter *ri;
+
+	ri = kmalloc(sizeof *ri, GFP_KERNEL);
+	if (!ri)
+		return NULL;
+
+	ri->ls = ls;
+	ri->entry = 0;
+	ri->next = NULL;
+
+	if (rsb_iter_next(ri)) {
+		rsb_iter_free(ri);
+		return NULL;
+	}
+
+	return ri;
+}
+
+static void *seq_start(struct seq_file *file, loff_t *pos)
+{
+	struct rsb_iter *ri;
+	loff_t n = *pos;
+
+	ri = rsb_iter_init(file->private);
+	if (!ri)
+		return NULL;
+
+	while (n--) {
+		if (rsb_iter_next(ri)) {
+			rsb_iter_free(ri);
+			return NULL;
+		}
+	}
+
+	return ri;
+}
+
+static void *seq_next(struct seq_file *file, void *iter_ptr, loff_t *pos)
+{
+	struct rsb_iter *ri = iter_ptr;
+
+	(*pos)++;
+
+	if (rsb_iter_next(ri)) {
+		rsb_iter_free(ri);
+		return NULL;
+	}
+
+	return ri;
+}
+
+static void seq_stop(struct seq_file *file, void *iter_ptr)
+{
+	/* nothing for now */
+}
+
+static int seq_show(struct seq_file *file, void *iter_ptr)
+{
+	struct rsb_iter *ri = iter_ptr;
+
+	print_resource(ri->rsb, file);
+
+	return 0;
+}
+
+static struct seq_operations dlm_seq_ops = {
+	.start = seq_start,
+	.next  = seq_next,
+	.stop  = seq_stop,
+	.show  = seq_show,
+};
+
+static int do_open(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq;
+	int ret;
+
+	ret = seq_open(file, &dlm_seq_ops);
+	if (ret)
+		return ret;
+
+	seq = file->private_data;
+	seq->private = inode->u.generic_ip;
+
+	return 0;
+}
+
+static struct file_operations dlm_fops = {
+	.owner   = THIS_MODULE,
+	.open    = do_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release
+};
+
+int dlm_create_debug_file(struct dlm_ls *ls)
+{
+	ls->ls_debug_dentry = debugfs_create_file(ls->ls_name,
+						  S_IFREG | S_IRUGO,
+						  dlm_root,
+						  ls,
+						  &dlm_fops);
+	return ls->ls_debug_dentry ? 0 : -ENOMEM;
+}
+
+void dlm_delete_debug_file(struct dlm_ls *ls)
+{
+	if (ls->ls_debug_dentry)
+		debugfs_remove(ls->ls_debug_dentry);
+}
+
+int dlm_register_debugfs(void)
+{
+	dlm_root = debugfs_create_dir("dlm", NULL);
+	return dlm_root ? 0 : -ENOMEM;
+}
+
+void dlm_unregister_debugfs(void)
+{
+	debugfs_remove(dlm_root);
+}
+

fs/dlm/device.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+/*
+ * device.c
+ *
+ * This is the userland interface to the DLM.
+ *
+ * The locking is done via a misc char device (find the
+ * registered minor number in /proc/misc).
+ *
+ * User code should not use this interface directly but
+ * call the library routines in libdlm.a instead.
+ *
+ */
+
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/signal.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+
+#include <linux/dlm.h>
+#include <linux/dlm_device.h>
+
+#include "lvb_table.h"
+
+static struct file_operations _dlm_fops;
+static const char *name_prefix="dlm";
+static struct list_head user_ls_list;
+static struct semaphore user_ls_lock;
+
+/* Lock infos are stored in here indexed by lock ID */
+static DEFINE_IDR(lockinfo_idr);
+static rwlock_t lockinfo_lock;
+
+/* Flags in li_flags */
+#define LI_FLAG_COMPLETE   1
+#define LI_FLAG_FIRSTLOCK  2
+#define LI_FLAG_PERSISTENT 3
+
+/* flags in ls_flags*/
+#define LS_FLAG_DELETED   1
+#define LS_FLAG_AUTOFREE  2
+
+
+#define LOCKINFO_MAGIC 0x53595324
+
+struct lock_info {
+	uint32_t li_magic;
+	uint8_t li_cmd;
+	int8_t	li_grmode;
+	int8_t  li_rqmode;
+	struct dlm_lksb li_lksb;
+	wait_queue_head_t li_waitq;
+	unsigned long li_flags;
+	void __user *li_castparam;
+	void __user *li_castaddr;
+	void __user *li_bastparam;
+	void __user *li_bastaddr;
+	void __user *li_pend_bastparam;
+	void __user *li_pend_bastaddr;
+	struct list_head li_ownerqueue;
+	struct file_info *li_file;
+	struct dlm_lksb __user *li_user_lksb;
+	struct semaphore li_firstlock;
+};
+
+/* A queued AST no less */
+struct ast_info {
+	struct dlm_lock_result result;
+	struct list_head list;
+	uint32_t lvb_updated;
+	uint32_t progress;      /* How much has been read */
+};
+
+/* One of these per userland lockspace */
+struct user_ls {
+	void    *ls_lockspace;
+	atomic_t ls_refcnt;
+	long     ls_flags;
+
+	/* Passed into misc_register() */
+	struct miscdevice ls_miscinfo;
+	struct list_head  ls_list;
+};
+
+/* misc_device info for the control device */
+static struct miscdevice ctl_device;
+
+/*
+ * Stuff we hang off the file struct.
+ * The first two are to cope with unlocking all the
+ * locks help by a process when it dies.
+ */
+struct file_info {
+	struct list_head    fi_li_list;  /* List of active lock_infos */
+	spinlock_t          fi_li_lock;
+	struct list_head    fi_ast_list; /* Queue of ASTs to be delivered */
+	spinlock_t          fi_ast_lock;
+	wait_queue_head_t   fi_wait;
+	struct user_ls     *fi_ls;
+	atomic_t            fi_refcnt;   /* Number of users */
+	unsigned long       fi_flags;    /* Bit 1 means the device is open */
+};
+
+
+/* get and put ops for file_info.
+   Actually I don't really like "get" and "put", but everyone
+   else seems to use them and I can't think of anything
+   nicer at the moment */
+static void get_file_info(struct file_info *f)
+{
+	atomic_inc(&f->fi_refcnt);
+}
+
+static void put_file_info(struct file_info *f)
+{
+	if (atomic_dec_and_test(&f->fi_refcnt))
+		kfree(f);
+}
+
+static void release_lockinfo(struct lock_info *li)
+{
+	put_file_info(li->li_file);
+
+	write_lock(&lockinfo_lock);
+	idr_remove(&lockinfo_idr, li->li_lksb.sb_lkid);
+	write_unlock(&lockinfo_lock);
+
+	if (li->li_lksb.sb_lvbptr)
+		kfree(li->li_lksb.sb_lvbptr);
+	kfree(li);
+
+	module_put(THIS_MODULE);
+}
+
+static struct lock_info *get_lockinfo(uint32_t lockid)
+{
+	struct lock_info *li;
+
+	read_lock(&lockinfo_lock);
+	li = idr_find(&lockinfo_idr, lockid);
+	read_unlock(&lockinfo_lock);
+
+	return li;
+}
+
+static int add_lockinfo(struct lock_info *li)
+{
+	int n;
+	int r;
+	int ret = -EINVAL;
+
+	write_lock(&lockinfo_lock);
+
+	if (idr_find(&lockinfo_idr, li->li_lksb.sb_lkid))
+		goto out_up;
+
+	ret = -ENOMEM;
+	r = idr_pre_get(&lockinfo_idr, GFP_KERNEL);
+	if (!r)
+		goto out_up;
+
+	r = idr_get_new_above(&lockinfo_idr, li, li->li_lksb.sb_lkid, &n);
+	if (r)
+		goto out_up;
+
+	if (n != li->li_lksb.sb_lkid) {
+		idr_remove(&lockinfo_idr, n);
+		goto out_up;
+	}
+
+	ret = 0;
+
+ out_up:
+	write_unlock(&lockinfo_lock);
+
+	return ret;
+}
+
+
+static struct user_ls *__find_lockspace(int minor)
+{
+	struct user_ls *lsinfo;
+
+	list_for_each_entry(lsinfo, &user_ls_list, ls_list) {
+		if (lsinfo->ls_miscinfo.minor == minor)
+			return lsinfo;
+	}
+	return NULL;
+}
+
+/* Find a lockspace struct given the device minor number */
+static struct user_ls *find_lockspace(int minor)
+{
+	struct user_ls *lsinfo;
+
+	down(&user_ls_lock);
+	lsinfo = __find_lockspace(minor);
+	up(&user_ls_lock);
+
+	return lsinfo;
+}
+
+static void add_lockspace_to_list(struct user_ls *lsinfo)
+{
+	down(&user_ls_lock);
+	list_add(&lsinfo->ls_list, &user_ls_list);
+	up(&user_ls_lock);
+}
+
+/* Register a lockspace with the DLM and create a misc
+   device for userland to access it */
+static int register_lockspace(char *name, struct user_ls **ls, int flags)
+{
+	struct user_ls *newls;
+	int status;
+	int namelen;
+
+	namelen = strlen(name)+strlen(name_prefix)+2;
+
+	newls = kmalloc(sizeof(struct user_ls), GFP_KERNEL);
+	if (!newls)
+		return -ENOMEM;
+	memset(newls, 0, sizeof(struct user_ls));
+
+	newls->ls_miscinfo.name = kmalloc(namelen, GFP_KERNEL);
+	if (!newls->ls_miscinfo.name) {
+		kfree(newls);
+		return -ENOMEM;
+	}
+
+	status = dlm_new_lockspace(name, strlen(name), &newls->ls_lockspace, 0,
+				   DLM_USER_LVB_LEN);
+	if (status != 0) {
+		kfree(newls->ls_miscinfo.name);
+		kfree(newls);
+		return status;
+	}
+
+	snprintf((char*)newls->ls_miscinfo.name, namelen, "%s_%s",
+		 name_prefix, name);
+
+	newls->ls_miscinfo.fops = &_dlm_fops;
+	newls->ls_miscinfo.minor = MISC_DYNAMIC_MINOR;
+
+	status = misc_register(&newls->ls_miscinfo);
+	if (status) {
+		printk(KERN_ERR "dlm: misc register failed for %s\n", name);
+		dlm_release_lockspace(newls->ls_lockspace, 0);
+		kfree(newls->ls_miscinfo.name);
+		kfree(newls);
+		return status;
+	}
+
+	if (flags & DLM_USER_LSFLG_AUTOFREE)
+		set_bit(LS_FLAG_AUTOFREE, &newls->ls_flags);
+
+	add_lockspace_to_list(newls);
+	*ls = newls;
+	return 0;
+}
+
+/* Called with the user_ls_lock semaphore held */
+static int unregister_lockspace(struct user_ls *lsinfo, int force)
+{
+	int status;
+
+	status = dlm_release_lockspace(lsinfo->ls_lockspace, force);
+	if (status)
+		return status;
+
+	status = misc_deregister(&lsinfo->ls_miscinfo);
+	if (status)
+		return status;
+
+	list_del(&lsinfo->ls_list);
+	set_bit(LS_FLAG_DELETED, &lsinfo->ls_flags);
+	lsinfo->ls_lockspace = NULL;
+	if (atomic_read(&lsinfo->ls_refcnt) == 0) {
+		kfree(lsinfo->ls_miscinfo.name);
+		kfree(lsinfo);
+	}
+
+	return 0;
+}
+
+/* Add it to userland's AST queue */
+static void add_to_astqueue(struct lock_info *li, void *astaddr, void *astparam,
+			    int lvb_updated)
+{
+	struct ast_info *ast = kmalloc(sizeof(struct ast_info), GFP_KERNEL);
+	if (!ast)
+		return;
+
+	memset(ast, 0, sizeof(*ast));
+	ast->result.user_astparam = astparam;
+	ast->result.user_astaddr  = astaddr;
+	ast->result.user_lksb     = li->li_user_lksb;
+	memcpy(&ast->result.lksb, &li->li_lksb, sizeof(struct dlm_lksb));
+	ast->lvb_updated = lvb_updated;
+
+	spin_lock(&li->li_file->fi_ast_lock);
+	list_add_tail(&ast->list, &li->li_file->fi_ast_list);
+	spin_unlock(&li->li_file->fi_ast_lock);
+	wake_up_interruptible(&li->li_file->fi_wait);
+}
+
+static void bast_routine(void *param, int mode)
+{
+	struct lock_info *li = param;
+
+	if (li && li->li_bastaddr)
+		add_to_astqueue(li, li->li_bastaddr, li->li_bastparam, 0);
+}
+
+/*
+ * This is the kernel's AST routine.
+ * All lock, unlock & query operations complete here.
+ * The only syncronous ops are those done during device close.
+ */
+static void ast_routine(void *param)
+{
+	struct lock_info *li = param;
+
+	/* Param may be NULL if a persistent lock is unlocked by someone else */
+	if (!li)
+		return;
+
+	/* If this is a succesful conversion then activate the blocking ast
+	 * args from the conversion request */
+	if (!test_bit(LI_FLAG_FIRSTLOCK, &li->li_flags) &&
+	    li->li_lksb.sb_status == 0) {
+
+		li->li_bastparam = li->li_pend_bastparam;
+		li->li_bastaddr = li->li_pend_bastaddr;
+		li->li_pend_bastaddr = NULL;
+	}
+
+	/* If it's an async request then post data to the user's AST queue. */
+	if (li->li_castaddr) {
+		int lvb_updated = 0;
+
+		/* See if the lvb has been updated */
+		if (dlm_lvb_operations[li->li_grmode+1][li->li_rqmode+1] == 1)
+			lvb_updated = 1;
+
+		if (li->li_lksb.sb_status == 0)
+			li->li_grmode = li->li_rqmode;
+
+		/* Only queue AST if the device is still open */
+		if (test_bit(1, &li->li_file->fi_flags))
+			add_to_astqueue(li, li->li_castaddr, li->li_castparam,
+					lvb_updated);
+
+		/* If it's a new lock operation that failed, then
+		 * remove it from the owner queue and free the
+		 * lock_info.
+		 */
+		if (test_and_clear_bit(LI_FLAG_FIRSTLOCK, &li->li_flags) &&
+		    li->li_lksb.sb_status != 0) {
+
+			/* Wait till dlm_lock() has finished */
+			down(&li->li_firstlock);
+			up(&li->li_firstlock);
+
+			spin_lock(&li->li_file->fi_li_lock);
+			list_del(&li->li_ownerqueue);
+			spin_unlock(&li->li_file->fi_li_lock);
+			release_lockinfo(li);
+			return;
+		}
+		/* Free unlocks & queries */
+		if (li->li_lksb.sb_status == -DLM_EUNLOCK ||
+		    li->li_cmd == DLM_USER_QUERY) {
+			release_lockinfo(li);
+		}
+	} else {
+		/* Synchronous request, just wake up the caller */
+		set_bit(LI_FLAG_COMPLETE, &li->li_flags);
+		wake_up_interruptible(&li->li_waitq);
+	}
+}
+
+/*
+ * Wait for the lock op to complete and return the status.
+ */
+static int wait_for_ast(struct lock_info *li)
+{
+	/* Wait for the AST routine to complete */
+	set_task_state(current, TASK_INTERRUPTIBLE);
+	while (!test_bit(LI_FLAG_COMPLETE, &li->li_flags))
+		schedule();
+
+	set_task_state(current, TASK_RUNNING);
+
+	return li->li_lksb.sb_status;
+}
+
+
+/* Open on control device */
+static int dlm_ctl_open(struct inode *inode, struct file *file)
+{
+	file->private_data = NULL;
+	return 0;
+}
+
+/* Close on control device */
+static int dlm_ctl_close(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+/* Open on lockspace device */
+static int dlm_open(struct inode *inode, struct file *file)
+{
+	struct file_info *f;
+	struct user_ls *lsinfo;
+
+	lsinfo = find_lockspace(iminor(inode));
+	if (!lsinfo)
+		return -ENOENT;
+
+	f = kmalloc(sizeof(struct file_info), GFP_KERNEL);
+	if (!f)
+		return -ENOMEM;
+
+	atomic_inc(&lsinfo->ls_refcnt);
+	INIT_LIST_HEAD(&f->fi_li_list);
+	INIT_LIST_HEAD(&f->fi_ast_list);
+	spin_lock_init(&f->fi_li_lock);
+	spin_lock_init(&f->fi_ast_lock);
+	init_waitqueue_head(&f->fi_wait);
+	f->fi_ls = lsinfo;
+	f->fi_flags = 0;
+	get_file_info(f);
+	set_bit(1, &f->fi_flags);
+
+	file->private_data = f;
+
+	return 0;
+}
+
+/* Check the user's version matches ours */
+static int check_version(struct dlm_write_request *req)
+{
+	if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
+	    (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
+	     req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
+
+		printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
+		       "user (%d.%d.%d) kernel (%d.%d.%d)\n",
+		       current->comm,
+		       current->pid,
+		       req->version[0],
+		       req->version[1],
+		       req->version[2],
+		       DLM_DEVICE_VERSION_MAJOR,
+		       DLM_DEVICE_VERSION_MINOR,
+		       DLM_DEVICE_VERSION_PATCH);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* Close on lockspace device */
+static int dlm_close(struct inode *inode, struct file *file)
+{
+	struct file_info *f = file->private_data;
+	struct lock_info li;
+	struct lock_info *old_li, *safe;
+	sigset_t tmpsig;
+	sigset_t allsigs;
+	struct user_ls *lsinfo;
+	DECLARE_WAITQUEUE(wq, current);
+
+	lsinfo = find_lockspace(iminor(inode));
+	if (!lsinfo)
+		return -ENOENT;
+
+	/* Mark this closed so that ASTs will not be delivered any more */
+	clear_bit(1, &f->fi_flags);
+
+	/* Block signals while we are doing this */
+	sigfillset(&allsigs);
+	sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
+
+	/* We use our own lock_info struct here, so that any
+	 * outstanding "real" ASTs will be delivered with the
+	 * corresponding "real" params, thus freeing the lock_info
+	 * that belongs the lock. This catches the corner case where
+	 * a lock is BUSY when we try to unlock it here
+	 */
+	memset(&li, 0, sizeof(li));
+	clear_bit(LI_FLAG_COMPLETE, &li.li_flags);
+	init_waitqueue_head(&li.li_waitq);
+	add_wait_queue(&li.li_waitq, &wq);
+
+	/*
+	 * Free any outstanding locks, they are on the
+	 * list in LIFO order so there should be no problems
+	 * about unlocking parents before children.
+	 */
+	list_for_each_entry_safe(old_li, safe, &f->fi_li_list, li_ownerqueue) {
+		int status;
+		int flags = 0;
+
+		/* Don't unlock persistent locks, just mark them orphaned */
+		if (test_bit(LI_FLAG_PERSISTENT, &old_li->li_flags)) {
+			list_del(&old_li->li_ownerqueue);
+
+			/* Update master copy */
+			/* TODO: Check locking core updates the local and
+			   remote ORPHAN flags */
+			li.li_lksb.sb_lkid = old_li->li_lksb.sb_lkid;
+			status = dlm_lock(f->fi_ls->ls_lockspace,
+					  old_li->li_grmode, &li.li_lksb,
+					  DLM_LKF_CONVERT|DLM_LKF_ORPHAN,
+					  NULL, 0, 0, ast_routine, NULL,
+					  NULL, NULL);
+			if (status != 0)
+				printk("dlm: Error orphaning lock %x: %d\n",
+				       old_li->li_lksb.sb_lkid, status);
+
+			/* But tidy our references in it */
+			release_lockinfo(old_li);
+			continue;
+		}
+
+		clear_bit(LI_FLAG_COMPLETE, &li.li_flags);
+
+		flags = DLM_LKF_FORCEUNLOCK;
+		if (old_li->li_grmode >= DLM_LOCK_PW)
+			flags |= DLM_LKF_IVVALBLK;
+
+		status = dlm_unlock(f->fi_ls->ls_lockspace,
+				    old_li->li_lksb.sb_lkid, flags,
+				    &li.li_lksb, &li);
+
+		/* Must wait for it to complete as the next lock could be its
+		 * parent */
+		if (status == 0)
+			wait_for_ast(&li);
+
+		/* Unlock suceeded, free the lock_info struct. */
+		if (status == 0)
+			release_lockinfo(old_li);
+	}
+
+	remove_wait_queue(&li.li_waitq, &wq);
+
+	/*
+	 * If this is the last reference to the lockspace
+	 * then free the struct. If it's an AUTOFREE lockspace
+	 * then free the whole thing.
+	 */
+	down(&user_ls_lock);
+	if (atomic_dec_and_test(&lsinfo->ls_refcnt)) {
+
+		if (lsinfo->ls_lockspace) {
+			if (test_bit(LS_FLAG_AUTOFREE, &lsinfo->ls_flags)) {
+				unregister_lockspace(lsinfo, 1);
+			}
+		} else {
+			kfree(lsinfo->ls_miscinfo.name);
+			kfree(lsinfo);
+		}
+	}
+	up(&user_ls_lock);
+	put_file_info(f);
+
+	/* Restore signals */
+	sigprocmask(SIG_SETMASK, &tmpsig, NULL);
+	recalc_sigpending();
+
+	return 0;
+}
+
+static int do_user_create_lockspace(struct file_info *fi, uint8_t cmd,
+				    struct dlm_lspace_params *kparams)
+{
+	int status;
+	struct user_ls *lsinfo;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	status = register_lockspace(kparams->name, &lsinfo, kparams->flags);
+
+	/* If it succeeded then return the minor number */
+	if (status == 0)
+		status = lsinfo->ls_miscinfo.minor;
+
+	return status;
+}
+
+static int do_user_remove_lockspace(struct file_info *fi, uint8_t cmd,
+				    struct dlm_lspace_params *kparams)
+{
+	int status;
+	int force = 1;
+	struct user_ls *lsinfo;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	down(&user_ls_lock);
+	lsinfo = __find_lockspace(kparams->minor);
+	if (!lsinfo) {
+		up(&user_ls_lock);
+		return -EINVAL;
+	}
+
+	if (kparams->flags & DLM_USER_LSFLG_FORCEFREE)
+		force = 2;
+
+	status = unregister_lockspace(lsinfo, force);
+	up(&user_ls_lock);
+
+	return status;
+}
+
+/* Read call, might block if no ASTs are waiting.
+ * It will only ever return one message at a time, regardless
+ * of how many are pending.
+ */
+static ssize_t dlm_read(struct file *file, char __user *buffer, size_t count,
+			loff_t *ppos)
+{
+	struct file_info *fi = file->private_data;
+	struct ast_info *ast;
+	int data_size;
+	int offset;
+	DECLARE_WAITQUEUE(wait, current);
+
+	if (count < sizeof(struct dlm_lock_result))
+		return -EINVAL;
+
+	spin_lock(&fi->fi_ast_lock);
+	if (list_empty(&fi->fi_ast_list)) {
+
+		/* No waiting ASTs.
+		 * Return EOF if the lockspace been deleted.
+		 */
+		if (test_bit(LS_FLAG_DELETED, &fi->fi_ls->ls_flags))
+			return 0;
+
+		if (file->f_flags & O_NONBLOCK) {
+			spin_unlock(&fi->fi_ast_lock);
+			return -EAGAIN;
+		}
+
+		add_wait_queue(&fi->fi_wait, &wait);
+
+	repeat:
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (list_empty(&fi->fi_ast_list) &&
+		    !signal_pending(current)) {
+
+			spin_unlock(&fi->fi_ast_lock);
+			schedule();
+			spin_lock(&fi->fi_ast_lock);
+			goto repeat;
+		}
+
+		current->state = TASK_RUNNING;
+		remove_wait_queue(&fi->fi_wait, &wait);
+
+		if (signal_pending(current)) {
+			spin_unlock(&fi->fi_ast_lock);
+			return -ERESTARTSYS;
+		}
+	}
+
+	ast = list_entry(fi->fi_ast_list.next, struct ast_info, list);
+	list_del(&ast->list);
+	spin_unlock(&fi->fi_ast_lock);
+
+	/* Work out the size of the returned data */
+	data_size = sizeof(struct dlm_lock_result);
+	if (ast->lvb_updated && ast->result.lksb.sb_lvbptr)
+		data_size += DLM_USER_LVB_LEN;
+
+	offset = sizeof(struct dlm_lock_result);
+
+	/* Room for the extended data ? */
+	if (count >= data_size) {
+
+		if (ast->lvb_updated && ast->result.lksb.sb_lvbptr) {
+			if (copy_to_user(buffer+offset,
+					 ast->result.lksb.sb_lvbptr,
+					 DLM_USER_LVB_LEN))
+				return -EFAULT;
+			ast->result.lvb_offset = offset;
+			offset += DLM_USER_LVB_LEN;
+		}
+	}
+
+	ast->result.length = data_size;
+	/* Copy the header now it has all the offsets in it */
+	if (copy_to_user(buffer, &ast->result, sizeof(struct dlm_lock_result)))
+		offset = -EFAULT;
+
+	/* If we only returned a header and there's more to come then put it
+	   back on the list */
+	if (count < data_size) {
+		spin_lock(&fi->fi_ast_lock);
+		list_add(&ast->list, &fi->fi_ast_list);
+		spin_unlock(&fi->fi_ast_lock);
+	} else
+		kfree(ast);
+	return offset;
+}
+
+static unsigned int dlm_poll(struct file *file, poll_table *wait)
+{
+	struct file_info *fi = file->private_data;
+
+	poll_wait(file, &fi->fi_wait, wait);
+
+	spin_lock(&fi->fi_ast_lock);
+	if (!list_empty(&fi->fi_ast_list)) {
+		spin_unlock(&fi->fi_ast_lock);
+		return POLLIN | POLLRDNORM;
+	}
+
+	spin_unlock(&fi->fi_ast_lock);
+	return 0;
+}
+
+static struct lock_info *allocate_lockinfo(struct file_info *fi, uint8_t cmd,
+					   struct dlm_lock_params *kparams)
+{
+	struct lock_info *li;
+
+	if (!try_module_get(THIS_MODULE))
+		return NULL;
+
+	li = kmalloc(sizeof(struct lock_info), GFP_KERNEL);
+	if (li) {
+		li->li_magic     = LOCKINFO_MAGIC;
+		li->li_file      = fi;
+		li->li_cmd       = cmd;
+		li->li_flags     = 0;
+		li->li_grmode    = -1;
+		li->li_rqmode    = -1;
+		li->li_pend_bastparam = NULL;
+		li->li_pend_bastaddr  = NULL;
+		li->li_castaddr   = NULL;
+		li->li_castparam  = NULL;
+		li->li_lksb.sb_lvbptr = NULL;
+		li->li_bastaddr  = kparams->bastaddr;
+		li->li_bastparam = kparams->bastparam;
+
+		get_file_info(fi);
+	}
+	return li;
+}
+
+static int do_user_lock(struct file_info *fi, uint8_t cmd,
+			struct dlm_lock_params *kparams)
+{
+	struct lock_info *li;
+	int status;
+
+	/*
+	 * Validate things that we need to have correct.
+	 */
+	if (!kparams->castaddr)
+		return -EINVAL;
+
+	if (!kparams->lksb)
+		return -EINVAL;
+
+	/* Persistent child locks are not available yet */
+	if ((kparams->flags & DLM_LKF_PERSISTENT) && kparams->parent)
+		return -EINVAL;
+
+        /* For conversions, there should already be a lockinfo struct,
+	   unless we are adopting an orphaned persistent lock */
+	if (kparams->flags & DLM_LKF_CONVERT) {
+
+		li = get_lockinfo(kparams->lkid);
+
+		/* If this is a persistent lock we will have to create a
+		   lockinfo again */
+		if (!li && DLM_LKF_PERSISTENT) {
+			li = allocate_lockinfo(fi, cmd, kparams);
+
+			li->li_lksb.sb_lkid = kparams->lkid;
+			li->li_castaddr  = kparams->castaddr;
+			li->li_castparam = kparams->castparam;
+
+			/* OK, this isn;t exactly a FIRSTLOCK but it is the
+			   first time we've used this lockinfo, and if things
+			   fail we want rid of it */
+			init_MUTEX_LOCKED(&li->li_firstlock);
+			set_bit(LI_FLAG_FIRSTLOCK, &li->li_flags);
+			add_lockinfo(li);
+
+			/* TODO: do a query to get the current state ?? */
+		}
+		if (!li)
+			return -EINVAL;
+
+		if (li->li_magic != LOCKINFO_MAGIC)
+			return -EINVAL;
+
+		/* For conversions don't overwrite the current blocking AST
+		   info so that:
+		   a) if a blocking AST fires before the conversion is queued
+		      it runs the current handler
+		   b) if the conversion is cancelled, the original blocking AST
+		      declaration is active
+		   The pend_ info is made active when the conversion
+		   completes.
+		*/
+		li->li_pend_bastaddr  = kparams->bastaddr;
+		li->li_pend_bastparam = kparams->bastparam;
+	} else {
+		li = allocate_lockinfo(fi, cmd, kparams);
+		if (!li)
+			return -ENOMEM;
+
+		/* semaphore to allow us to complete our work before
+  		   the AST routine runs. In fact we only need (and use) this
+		   when the initial lock fails */
+		init_MUTEX_LOCKED(&li->li_firstlock);
+		set_bit(LI_FLAG_FIRSTLOCK, &li->li_flags);
+	}
+
+	li->li_user_lksb = kparams->lksb;
+	li->li_castaddr  = kparams->castaddr;
+	li->li_castparam = kparams->castparam;
+	li->li_lksb.sb_lkid = kparams->lkid;
+	li->li_rqmode    = kparams->mode;
+	if (kparams->flags & DLM_LKF_PERSISTENT)
+		set_bit(LI_FLAG_PERSISTENT, &li->li_flags);
+
+	/* Copy in the value block */
+	if (kparams->flags & DLM_LKF_VALBLK) {
+		if (!li->li_lksb.sb_lvbptr) {
+			li->li_lksb.sb_lvbptr = kmalloc(DLM_USER_LVB_LEN,
+							GFP_KERNEL);
+			if (!li->li_lksb.sb_lvbptr) {
+				status = -ENOMEM;
+				goto out_err;
+			}
+		}
+
+		memcpy(li->li_lksb.sb_lvbptr, kparams->lvb, DLM_USER_LVB_LEN);
+	}
+
+	/* Lock it ... */
+	status = dlm_lock(fi->fi_ls->ls_lockspace,
+			  kparams->mode, &li->li_lksb,
+			  kparams->flags,
+			  kparams->name, kparams->namelen,
+			  kparams->parent,
+			  ast_routine,
+			  li,
+			  (li->li_pend_bastaddr || li->li_bastaddr) ?
+			   bast_routine : NULL,
+			  kparams->range.ra_end ? &kparams->range : NULL);
+	if (status)
+		goto out_err;
+
+	/* If it succeeded (this far) with a new lock then keep track of
+	   it on the file's lockinfo list */
+	if (!status && test_bit(LI_FLAG_FIRSTLOCK, &li->li_flags)) {
+
+		spin_lock(&fi->fi_li_lock);
+		list_add(&li->li_ownerqueue, &fi->fi_li_list);
+		spin_unlock(&fi->fi_li_lock);
+		if (add_lockinfo(li))
+			printk(KERN_WARNING "Add lockinfo failed\n");
+
+		up(&li->li_firstlock);
+	}
+
+	/* Return the lockid as the user needs it /now/ */
+	return li->li_lksb.sb_lkid;
+
+ out_err:
+	if (test_bit(LI_FLAG_FIRSTLOCK, &li->li_flags))
+		release_lockinfo(li);
+	return status;
+
+}
+
+static int do_user_unlock(struct file_info *fi, uint8_t cmd,
+			  struct dlm_lock_params *kparams)
+{
+	struct lock_info *li;
+	int status;
+	int convert_cancel = 0;
+
+	li = get_lockinfo(kparams->lkid);
+	if (!li) {
+		li = allocate_lockinfo(fi, cmd, kparams);
+		spin_lock(&fi->fi_li_lock);
+		list_add(&li->li_ownerqueue, &fi->fi_li_list);
+		spin_unlock(&fi->fi_li_lock);
+	}
+ 	if (!li)
+		return -ENOMEM;
+
+	if (li->li_magic != LOCKINFO_MAGIC)
+		return -EINVAL;
+
+	li->li_user_lksb = kparams->lksb;
+	li->li_castparam = kparams->castparam;
+	li->li_cmd       = cmd;
+
+	/* Cancelling a conversion doesn't remove the lock...*/
+	if (kparams->flags & DLM_LKF_CANCEL && li->li_grmode != -1)
+		convert_cancel = 1;
+
+	/* dlm_unlock() passes a 0 for castaddr which means don't overwrite
+	   the existing li_castaddr as that's the completion routine for
+	   unlocks. dlm_unlock_wait() specifies a new AST routine to be
+	   executed when the unlock completes. */
+	if (kparams->castaddr)
+		li->li_castaddr = kparams->castaddr;
+
+	/* Use existing lksb & astparams */
+	status = dlm_unlock(fi->fi_ls->ls_lockspace,
+			     kparams->lkid,
+			     kparams->flags, &li->li_lksb, li);
+
+	if (!status && !convert_cancel) {
+		spin_lock(&fi->fi_li_lock);
+		list_del(&li->li_ownerqueue);
+		spin_unlock(&fi->fi_li_lock);
+	}
+
+	return status;
+}
+
+/* Write call, submit a locking request */
+static ssize_t dlm_write(struct file *file, const char __user *buffer,
+			 size_t count, loff_t *ppos)
+{
+	struct file_info *fi = file->private_data;
+	struct dlm_write_request *kparams;
+	sigset_t tmpsig;
+	sigset_t allsigs;
+	int status;
+
+	/* -1 because lock name is optional */
+	if (count < sizeof(struct dlm_write_request)-1)
+		return -EINVAL;
+
+	/* Has the lockspace been deleted */
+	if (fi && test_bit(LS_FLAG_DELETED, &fi->fi_ls->ls_flags))
+		return -ENOENT;
+
+	kparams = kmalloc(count, GFP_KERNEL);
+	if (!kparams)
+		return -ENOMEM;
+
+	status = -EFAULT;
+	/* Get the command info */
+	if (copy_from_user(kparams, buffer, count))
+		goto out_free;
+
+	status = -EBADE;
+	if (check_version(kparams))
+		goto out_free;
+
+	/* Block signals while we are doing this */
+	sigfillset(&allsigs);
+	sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
+
+	status = -EINVAL;
+	switch (kparams->cmd)
+	{
+	case DLM_USER_LOCK:
+		if (!fi) goto out_sig;
+		status = do_user_lock(fi, kparams->cmd, &kparams->i.lock);
+		break;
+
+	case DLM_USER_UNLOCK:
+		if (!fi) goto out_sig;
+		status = do_user_unlock(fi, kparams->cmd, &kparams->i.lock);
+		break;
+
+	case DLM_USER_CREATE_LOCKSPACE:
+		if (fi) goto out_sig;
+		status = do_user_create_lockspace(fi, kparams->cmd,
+						  &kparams->i.lspace);
+		break;
+
+	case DLM_USER_REMOVE_LOCKSPACE:
+		if (fi) goto out_sig;
+		status = do_user_remove_lockspace(fi, kparams->cmd,
+						  &kparams->i.lspace);
+		break;
+	default:
+		printk("Unknown command passed to DLM device : %d\n",
+			kparams->cmd);
+		break;
+	}
+
+ out_sig:
+	/* Restore signals */
+	sigprocmask(SIG_SETMASK, &tmpsig, NULL);
+	recalc_sigpending();
+
+ out_free:
+	kfree(kparams);
+	if (status == 0)
+		return count;
+	else
+		return status;
+}
+
+static struct file_operations _dlm_fops = {
+      .open    = dlm_open,
+      .release = dlm_close,
+      .read    = dlm_read,
+      .write   = dlm_write,
+      .poll    = dlm_poll,
+      .owner   = THIS_MODULE,
+};
+
+static struct file_operations _dlm_ctl_fops = {
+      .open    = dlm_ctl_open,
+      .release = dlm_ctl_close,
+      .write   = dlm_write,
+      .owner   = THIS_MODULE,
+};
+
+/*
+ * Create control device
+ */
+static int __init dlm_device_init(void)
+{
+	int r;
+
+	INIT_LIST_HEAD(&user_ls_list);
+	init_MUTEX(&user_ls_lock);
+	rwlock_init(&lockinfo_lock);
+
+	ctl_device.name = "dlm-control";
+	ctl_device.fops = &_dlm_ctl_fops;
+	ctl_device.minor = MISC_DYNAMIC_MINOR;
+
+	r = misc_register(&ctl_device);
+	if (r) {
+		printk(KERN_ERR "dlm: misc_register failed for control dev\n");
+		return r;
+	}
+
+	return 0;
+}
+
+static void __exit dlm_device_exit(void)
+{
+	misc_deregister(&ctl_device);
+}
+
+MODULE_DESCRIPTION("Distributed Lock Manager device interface");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+module_init(dlm_device_init);
+module_exit(dlm_device_exit);

fs/dlm/dir.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "lowcomms.h"
+#include "rcom.h"
+#include "config.h"
+#include "memory.h"
+#include "recover.h"
+#include "util.h"
+#include "lock.h"
+#include "dir.h"
+
+
+static void put_free_de(struct dlm_ls *ls, struct dlm_direntry *de)
+{
+	spin_lock(&ls->ls_recover_list_lock);
+	list_add(&de->list, &ls->ls_recover_list);
+	spin_unlock(&ls->ls_recover_list_lock);
+}
+
+static struct dlm_direntry *get_free_de(struct dlm_ls *ls, int len)
+{
+	int found = FALSE;
+	struct dlm_direntry *de;
+
+	spin_lock(&ls->ls_recover_list_lock);
+	list_for_each_entry(de, &ls->ls_recover_list, list) {
+		if (de->length == len) {
+			list_del(&de->list);
+			de->master_nodeid = 0;
+			memset(de->name, 0, len);
+			found = TRUE;
+			break;
+		}
+	}
+	spin_unlock(&ls->ls_recover_list_lock);
+
+	if (!found)
+		de = allocate_direntry(ls, len);
+	return de;
+}
+
+void dlm_clear_free_entries(struct dlm_ls *ls)
+{
+	struct dlm_direntry *de;
+
+	spin_lock(&ls->ls_recover_list_lock);
+	while (!list_empty(&ls->ls_recover_list)) {
+		de = list_entry(ls->ls_recover_list.next, struct dlm_direntry,
+				list);
+		list_del(&de->list);
+		free_direntry(de);
+	}
+	spin_unlock(&ls->ls_recover_list_lock);
+}
+
+/*
+ * We use the upper 16 bits of the hash value to select the directory node.
+ * Low bits are used for distribution of rsb's among hash buckets on each node.
+ *
+ * To give the exact range wanted (0 to num_nodes-1), we apply a modulus of
+ * num_nodes to the hash value.  This value in the desired range is used as an
+ * offset into the sorted list of nodeid's to give the particular nodeid.
+ */
+
+int dlm_hash2nodeid(struct dlm_ls *ls, uint32_t hash)
+{
+	struct list_head *tmp;
+	struct dlm_member *memb = NULL;
+	uint32_t node, n = 0;
+	int nodeid;
+
+	if (ls->ls_num_nodes == 1) {
+		nodeid = dlm_our_nodeid();
+		goto out;
+	}
+
+	if (ls->ls_node_array) {
+		node = (hash >> 16) % ls->ls_total_weight;
+		nodeid = ls->ls_node_array[node];
+		goto out;
+	}
+
+	/* make_member_array() failed to kmalloc ls_node_array... */
+
+	node = (hash >> 16) % ls->ls_num_nodes;
+
+	list_for_each(tmp, &ls->ls_nodes) {
+		if (n++ != node)
+			continue;
+		memb = list_entry(tmp, struct dlm_member, list);
+		break;
+	}
+
+	DLM_ASSERT(memb , printk("num_nodes=%u n=%u node=%u\n",
+				 ls->ls_num_nodes, n, node););
+	nodeid = memb->nodeid;
+ out:
+	return nodeid;
+}
+
+int dlm_dir_nodeid(struct dlm_rsb *r)
+{
+	return dlm_hash2nodeid(r->res_ls, r->res_hash);
+}
+
+static inline uint32_t dir_hash(struct dlm_ls *ls, char *name, int len)
+{
+	uint32_t val;
+
+	val = jhash(name, len, 0);
+	val &= (ls->ls_dirtbl_size - 1);
+
+	return val;
+}
+
+static void add_entry_to_hash(struct dlm_ls *ls, struct dlm_direntry *de)
+{
+	uint32_t bucket;
+
+	bucket = dir_hash(ls, de->name, de->length);
+	list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
+}
+
+static struct dlm_direntry *search_bucket(struct dlm_ls *ls, char *name,
+					  int namelen, uint32_t bucket)
+{
+	struct dlm_direntry *de;
+
+	list_for_each_entry(de, &ls->ls_dirtbl[bucket].list, list) {
+		if (de->length == namelen && !memcmp(name, de->name, namelen))
+			goto out;
+	}
+	de = NULL;
+ out:
+	return de;
+}
+
+void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, char *name, int namelen)
+{
+	struct dlm_direntry *de;
+	uint32_t bucket;
+
+	bucket = dir_hash(ls, name, namelen);
+
+	write_lock(&ls->ls_dirtbl[bucket].lock);
+
+	de = search_bucket(ls, name, namelen, bucket);
+
+	if (!de) {
+		log_error(ls, "remove fr %u none", nodeid);
+		goto out;
+	}
+
+	if (de->master_nodeid != nodeid) {
+		log_error(ls, "remove fr %u ID %u", nodeid, de->master_nodeid);
+		goto out;
+	}
+
+	list_del(&de->list);
+	free_direntry(de);
+ out:
+	write_unlock(&ls->ls_dirtbl[bucket].lock);
+}
+
+void dlm_dir_clear(struct dlm_ls *ls)
+{
+	struct list_head *head;
+	struct dlm_direntry *de;
+	int i;
+
+	DLM_ASSERT(list_empty(&ls->ls_recover_list), );
+
+	for (i = 0; i < ls->ls_dirtbl_size; i++) {
+		write_lock(&ls->ls_dirtbl[i].lock);
+		head = &ls->ls_dirtbl[i].list;
+		while (!list_empty(head)) {
+			de = list_entry(head->next, struct dlm_direntry, list);
+			list_del(&de->list);
+			put_free_de(ls, de);
+		}
+		write_unlock(&ls->ls_dirtbl[i].lock);
+	}
+}
+
+int dlm_recover_directory(struct dlm_ls *ls)
+{
+	struct dlm_member *memb;
+	struct dlm_direntry *de;
+	char *b, *last_name = NULL;
+	int error = -ENOMEM, last_len, count = 0;
+	uint16_t namelen;
+
+	log_debug(ls, "dlm_recover_directory");
+
+	if (dlm_no_directory(ls))
+		goto out_status;
+
+	dlm_dir_clear(ls);
+
+	last_name = kmalloc(DLM_RESNAME_MAXLEN, GFP_KERNEL);
+	if (!last_name)
+		goto out;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		memset(last_name, 0, DLM_RESNAME_MAXLEN);
+		last_len = 0;
+
+		for (;;) {
+			error = dlm_recovery_stopped(ls);
+			if (error)
+				goto out_free;
+
+			error = dlm_rcom_names(ls, memb->nodeid,
+					       last_name, last_len);
+			if (error)
+				goto out_free;
+
+			schedule();
+
+			/*
+			 * pick namelen/name pairs out of received buffer
+			 */
+
+			b = ls->ls_recover_buf + sizeof(struct dlm_rcom);
+
+			for (;;) {
+				memcpy(&namelen, b, sizeof(uint16_t));
+				namelen = be16_to_cpu(namelen);
+				b += sizeof(uint16_t);
+
+				/* namelen of 0xFFFFF marks end of names for
+				   this node; namelen of 0 marks end of the
+				   buffer */
+
+				if (namelen == 0xFFFF)
+					goto done;
+				if (!namelen)
+					break;
+
+				error = -ENOMEM;
+				de = get_free_de(ls, namelen);
+				if (!de)
+					goto out_free;
+
+				de->master_nodeid = memb->nodeid;
+				de->length = namelen;
+				last_len = namelen;
+				memcpy(de->name, b, namelen);
+				memcpy(last_name, b, namelen);
+				b += namelen;
+
+				add_entry_to_hash(ls, de);
+				count++;
+			}
+		}
+         done:
+		;
+	}
+
+ out_status:
+	error = 0;
+	dlm_set_recover_status(ls, DLM_RS_DIR);
+	log_debug(ls, "dlm_recover_directory %d entries", count);
+ out_free:
+	kfree(last_name);
+ out:
+	dlm_clear_free_entries(ls);
+	return error;
+}
+
+static int get_entry(struct dlm_ls *ls, int nodeid, char *name,
+		     int namelen, int *r_nodeid)
+{
+	struct dlm_direntry *de, *tmp;
+	uint32_t bucket;
+
+	bucket = dir_hash(ls, name, namelen);
+
+	write_lock(&ls->ls_dirtbl[bucket].lock);
+	de = search_bucket(ls, name, namelen, bucket);
+	if (de) {
+		*r_nodeid = de->master_nodeid;
+		write_unlock(&ls->ls_dirtbl[bucket].lock);
+		if (*r_nodeid == nodeid)
+			return -EEXIST;
+		return 0;
+	}
+
+	write_unlock(&ls->ls_dirtbl[bucket].lock);
+
+	de = allocate_direntry(ls, namelen);
+	if (!de)
+		return -ENOMEM;
+
+	de->master_nodeid = nodeid;
+	de->length = namelen;
+	memcpy(de->name, name, namelen);
+
+	write_lock(&ls->ls_dirtbl[bucket].lock);
+	tmp = search_bucket(ls, name, namelen, bucket);
+	if (tmp) {
+		free_direntry(de);
+		de = tmp;
+	} else {
+		list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
+	}
+	*r_nodeid = de->master_nodeid;
+	write_unlock(&ls->ls_dirtbl[bucket].lock);
+	return 0;
+}
+
+int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
+		   int *r_nodeid)
+{
+	return get_entry(ls, nodeid, name, namelen, r_nodeid);
+}
+
+/* Copy the names of master rsb's into the buffer provided.
+   Only select names whose dir node is the given nodeid. */
+
+void dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
+ 			   char *outbuf, int outlen, int nodeid)
+{
+	struct list_head *list;
+	struct dlm_rsb *start_r = NULL, *r = NULL;
+	int offset = 0, start_namelen, error, dir_nodeid;
+	char *start_name;
+	uint16_t be_namelen;
+
+	/*
+	 * Find the rsb where we left off (or start again)
+	 */
+
+	start_namelen = inlen;
+	start_name = inbuf;
+
+	if (start_namelen > 1) {
+		/*
+		 * We could also use a find_rsb_root() function here that
+		 * searched the ls_root_list.
+		 */
+		error = dlm_find_rsb(ls, start_name, start_namelen, R_MASTER,
+				     &start_r);
+		DLM_ASSERT(!error && start_r,
+			   printk("error %d\n", error););
+		DLM_ASSERT(!list_empty(&start_r->res_root_list),
+			   dlm_print_rsb(start_r););
+		dlm_put_rsb(start_r);
+	}
+
+	/*
+	 * Send rsb names for rsb's we're master of and whose directory node
+	 * matches the requesting node.
+	 */
+
+	down_read(&ls->ls_root_sem);
+	if (start_r)
+		list = start_r->res_root_list.next;
+	else
+		list = ls->ls_root_list.next;
+
+	for (offset = 0; list != &ls->ls_root_list; list = list->next) {
+		r = list_entry(list, struct dlm_rsb, res_root_list);
+		if (r->res_nodeid)
+			continue;
+
+		dir_nodeid = dlm_dir_nodeid(r);
+		if (dir_nodeid != nodeid)
+			continue;
+
+		/*
+		 * The block ends when we can't fit the following in the
+		 * remaining buffer space:
+		 * namelen (uint16_t) +
+		 * name (r->res_length) +
+		 * end-of-block record 0x0000 (uint16_t)
+		 */
+
+		if (offset + sizeof(uint16_t)*2 + r->res_length > outlen) {
+			/* Write end-of-block record */
+			be_namelen = 0;
+			memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
+			offset += sizeof(uint16_t);
+			goto out;
+		}
+
+		be_namelen = cpu_to_be16(r->res_length);
+		memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
+		offset += sizeof(uint16_t);
+		memcpy(outbuf + offset, r->res_name, r->res_length);
+		offset += r->res_length;
+	}
+
+	/*
+	 * If we've reached the end of the list (and there's room) write a
+	 * terminating record.
+	 */
+
+	if ((list == &ls->ls_root_list) &&
+	    (offset + sizeof(uint16_t) <= outlen)) {
+		be_namelen = 0xFFFF;
+		memcpy(outbuf + offset, &be_namelen, sizeof(uint16_t));
+		offset += sizeof(uint16_t);
+	}
+
+ out:
+	up_read(&ls->ls_root_sem);
+}
+

fs/dlm/dir.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __DIR_DOT_H__
+#define __DIR_DOT_H__
+
+
+int dlm_dir_nodeid(struct dlm_rsb *rsb);
+int dlm_hash2nodeid(struct dlm_ls *ls, uint32_t hash);
+void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, char *name, int len);
+void dlm_dir_clear(struct dlm_ls *ls);
+void dlm_clear_free_entries(struct dlm_ls *ls);
+int dlm_recover_directory(struct dlm_ls *ls);
+int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
+	int *r_nodeid);
+void dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
+	char *outbuf, int outlen, int nodeid);
+
+#endif				/* __DIR_DOT_H__ */
+

fs/dlm/dlm_internal.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __DLM_INTERNAL_DOT_H__
+#define __DLM_INTERNAL_DOT_H__
+
+/*
+ * This is the main header file to be included in each DLM source file.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/random.h>
+#include <linux/delay.h>
+#include <linux/socket.h>
+#include <linux/kthread.h>
+#include <linux/kobject.h>
+#include <linux/kref.h>
+#include <linux/kernel.h>
+#include <linux/jhash.h>
+#include <asm/semaphore.h>
+#include <asm/uaccess.h>
+
+#include <linux/dlm.h>
+
+#define DLM_LOCKSPACE_LEN	64
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#if (BITS_PER_LONG == 64)
+#define PRIx64 "lx"
+#else
+#define PRIx64 "Lx"
+#endif
+
+/* Size of the temp buffer midcomms allocates on the stack.
+   We try to make this large enough so most messages fit.
+   FIXME: should sctp make this unnecessary? */
+
+#define DLM_INBUF_LEN		148
+
+struct dlm_ls;
+struct dlm_lkb;
+struct dlm_rsb;
+struct dlm_member;
+struct dlm_lkbtable;
+struct dlm_rsbtable;
+struct dlm_dirtable;
+struct dlm_direntry;
+struct dlm_recover;
+struct dlm_header;
+struct dlm_message;
+struct dlm_rcom;
+struct dlm_mhandle;
+
+#define log_print(fmt, args...) \
+	printk(KERN_ERR "dlm: "fmt"\n" , ##args)
+#define log_error(ls, fmt, args...) \
+	printk(KERN_ERR "dlm: %s: " fmt "\n", (ls)->ls_name , ##args)
+
+#ifdef DLM_LOG_DEBUG
+#define log_debug(ls, fmt, args...) log_error(ls, fmt, ##args)
+#else
+#define log_debug(ls, fmt, args...)
+#endif
+
+#define DLM_ASSERT(x, do) \
+{ \
+  if (!(x)) \
+  { \
+    printk(KERN_ERR "\nDLM:  Assertion failed on line %d of file %s\n" \
+               "DLM:  assertion:  \"%s\"\n" \
+               "DLM:  time = %lu\n", \
+               __LINE__, __FILE__, #x, jiffies); \
+    {do} \
+    printk("\n"); \
+    BUG(); \
+    panic("DLM:  Record message above and reboot.\n"); \
+  } \
+}
+
+
+struct dlm_direntry {
+	struct list_head	list;
+	uint32_t		master_nodeid;
+	uint16_t		length;
+	char			name[1];
+};
+
+struct dlm_dirtable {
+	struct list_head	list;
+	rwlock_t		lock;
+};
+
+struct dlm_rsbtable {
+	struct list_head	list;
+	struct list_head	toss;
+	rwlock_t		lock;
+};
+
+struct dlm_lkbtable {
+	struct list_head	list;
+	rwlock_t		lock;
+	uint16_t		counter;
+};
+
+/*
+ * Lockspace member (per node in a ls)
+ */
+
+struct dlm_member {
+	struct list_head	list;
+	int			nodeid;
+	int			weight;
+};
+
+/*
+ * Save and manage recovery state for a lockspace.
+ */
+
+struct dlm_recover {
+	struct list_head	list;
+	int			*nodeids;
+	int			node_count;
+	uint64_t		seq;
+};
+
+/*
+ * Pass input args to second stage locking function.
+ */
+
+struct dlm_args {
+	uint32_t		flags;
+	void			*astaddr;
+	long			astparam;
+	void			*bastaddr;
+	int			mode;
+	struct dlm_lksb		*lksb;
+	struct dlm_range	*range;
+};
+
+
+/*
+ * Lock block
+ *
+ * A lock can be one of three types:
+ *
+ * local copy      lock is mastered locally
+ *                 (lkb_nodeid is zero and DLM_LKF_MSTCPY is not set)
+ * process copy    lock is mastered on a remote node
+ *                 (lkb_nodeid is non-zero and DLM_LKF_MSTCPY is not set)
+ * master copy     master node's copy of a lock owned by remote node
+ *                 (lkb_nodeid is non-zero and DLM_LKF_MSTCPY is set)
+ *
+ * lkb_exflags: a copy of the most recent flags arg provided to dlm_lock or
+ * dlm_unlock.  The dlm does not modify these or use any private flags in
+ * this field; it only contains DLM_LKF_ flags from dlm.h.  These flags
+ * are sent as-is to the remote master when the lock is remote.
+ *
+ * lkb_flags: internal dlm flags (DLM_IFL_ prefix) from dlm_internal.h.
+ * Some internal flags are shared between the master and process nodes;
+ * these shared flags are kept in the lower two bytes.  One of these
+ * flags set on the master copy will be propagated to the process copy
+ * and v.v.  Other internal flags are private to the master or process
+ * node (e.g. DLM_IFL_MSTCPY).  These are kept in the high two bytes.
+ *
+ * lkb_sbflags: status block flags.  These flags are copied directly into
+ * the caller's lksb.sb_flags prior to the dlm_lock/dlm_unlock completion
+ * ast.  All defined in dlm.h with DLM_SBF_ prefix.
+ *
+ * lkb_status: the lock status indicates which rsb queue the lock is
+ * on, grant, convert, or wait.  DLM_LKSTS_ WAITING/GRANTED/CONVERT
+ *
+ * lkb_wait_type: the dlm message type (DLM_MSG_ prefix) for which a
+ * reply is needed.  Only set when the lkb is on the lockspace waiters
+ * list awaiting a reply from a remote node.
+ *
+ * lkb_nodeid: when the lkb is a local copy, nodeid is 0; when the lkb
+ * is a master copy, nodeid specifies the remote lock holder, when the
+ * lkb is a process copy, the nodeid specifies the lock master.
+ */
+
+/* lkb_ast_type */
+
+#define AST_COMP		1
+#define AST_BAST		2
+
+/* lkb_range[] */
+
+#define GR_RANGE_START		0
+#define GR_RANGE_END		1
+#define RQ_RANGE_START		2
+#define RQ_RANGE_END		3
+
+/* lkb_status */
+
+#define DLM_LKSTS_WAITING	1
+#define DLM_LKSTS_GRANTED	2
+#define DLM_LKSTS_CONVERT	3
+
+/* lkb_flags */
+
+#define DLM_IFL_MSTCPY		0x00010000
+#define DLM_IFL_RESEND		0x00020000
+#define DLM_IFL_RANGE		0x00000001
+
+struct dlm_lkb {
+	struct dlm_rsb		*lkb_resource;	/* the rsb */
+	struct kref		lkb_ref;
+	int			lkb_nodeid;	/* copied from rsb */
+	int			lkb_ownpid;	/* pid of lock owner */
+	uint32_t		lkb_id;		/* our lock ID */
+	uint32_t		lkb_remid;	/* lock ID on remote partner */
+	uint32_t		lkb_exflags;	/* external flags from caller */
+	uint32_t		lkb_sbflags;	/* lksb flags */
+	uint32_t		lkb_flags;	/* internal flags */
+	uint32_t		lkb_lvbseq;	/* lvb sequence number */
+
+	int8_t			lkb_status;     /* granted, waiting, convert */
+	int8_t			lkb_rqmode;	/* requested lock mode */
+	int8_t			lkb_grmode;	/* granted lock mode */
+	int8_t			lkb_bastmode;	/* requested mode */
+	int8_t			lkb_highbast;	/* highest mode bast sent for */
+
+	int8_t			lkb_wait_type;	/* type of reply waiting for */
+	int8_t			lkb_ast_type;	/* type of ast queued for */
+
+	struct list_head	lkb_idtbl_list;	/* lockspace lkbtbl */
+	struct list_head	lkb_statequeue;	/* rsb g/c/w list */
+	struct list_head	lkb_rsb_lookup;	/* waiting for rsb lookup */
+	struct list_head	lkb_wait_reply;	/* waiting for remote reply */
+	struct list_head	lkb_astqueue;	/* need ast to be sent */
+
+	uint64_t		*lkb_range;	/* array of gr/rq ranges */
+	char			*lkb_lvbptr;
+	struct dlm_lksb		*lkb_lksb;      /* caller's status block */
+	void			*lkb_astaddr;	/* caller's ast function */
+	void			*lkb_bastaddr;	/* caller's bast function */
+	long			lkb_astparam;	/* caller's ast arg */
+};
+
+
+struct dlm_rsb {
+	struct dlm_ls		*res_ls;	/* the lockspace */
+	struct kref		res_ref;
+	struct semaphore	res_sem;
+	unsigned long		res_flags;
+	int			res_length;	/* length of rsb name */
+	int			res_nodeid;
+	uint32_t                res_lvbseq;
+	uint32_t		res_hash;
+	uint32_t		res_bucket;	/* rsbtbl */
+	unsigned long		res_toss_time;
+	uint32_t		res_first_lkid;
+	struct list_head	res_lookup;	/* lkbs waiting on first */
+	struct list_head	res_hashchain;	/* rsbtbl */
+	struct list_head	res_grantqueue;
+	struct list_head	res_convertqueue;
+	struct list_head	res_waitqueue;
+
+	struct list_head	res_root_list;	    /* used for recovery */
+	struct list_head	res_recover_list;   /* used for recovery */
+	int			res_recover_locks_count;
+
+	char			*res_lvbptr;
+	char			res_name[1];
+};
+
+/* find_rsb() flags */
+
+#define R_MASTER		1	/* only return rsb if it's a master */
+#define R_CREATE		2	/* create/add rsb if not found */
+
+/* rsb_flags */
+
+enum rsb_flags {
+	RSB_MASTER_UNCERTAIN,
+	RSB_VALNOTVALID,
+	RSB_VALNOTVALID_PREV,
+	RSB_NEW_MASTER,
+	RSB_NEW_MASTER2,
+	RSB_RECOVER_CONVERT,
+};
+
+static inline void rsb_set_flag(struct dlm_rsb *r, enum rsb_flags flag)
+{
+	__set_bit(flag, &r->res_flags);
+}
+
+static inline void rsb_clear_flag(struct dlm_rsb *r, enum rsb_flags flag)
+{
+	__clear_bit(flag, &r->res_flags);
+}
+
+static inline int rsb_flag(struct dlm_rsb *r, enum rsb_flags flag)
+{
+	return test_bit(flag, &r->res_flags);
+}
+
+
+/* dlm_header is first element of all structs sent between nodes */
+
+#define DLM_HEADER_MAJOR	0x00020000
+#define DLM_HEADER_MINOR	0x00000001
+
+#define DLM_MSG			1
+#define DLM_RCOM		2
+
+struct dlm_header {
+	uint32_t		h_version;
+	uint32_t		h_lockspace;
+	uint32_t		h_nodeid;	/* nodeid of sender */
+	uint16_t		h_length;
+	uint8_t			h_cmd;		/* DLM_MSG, DLM_RCOM */
+	uint8_t			h_pad;
+};
+
+
+#define DLM_MSG_REQUEST		1
+#define DLM_MSG_CONVERT		2
+#define DLM_MSG_UNLOCK		3
+#define DLM_MSG_CANCEL		4
+#define DLM_MSG_REQUEST_REPLY	5
+#define DLM_MSG_CONVERT_REPLY	6
+#define DLM_MSG_UNLOCK_REPLY	7
+#define DLM_MSG_CANCEL_REPLY	8
+#define DLM_MSG_GRANT		9
+#define DLM_MSG_BAST		10
+#define DLM_MSG_LOOKUP		11
+#define DLM_MSG_REMOVE		12
+#define DLM_MSG_LOOKUP_REPLY	13
+
+struct dlm_message {
+	struct dlm_header	m_header;
+	uint32_t		m_type;		/* DLM_MSG_ */
+	uint32_t		m_nodeid;
+	uint32_t		m_pid;
+	uint32_t		m_lkid;		/* lkid on sender */
+	uint32_t		m_remid;	/* lkid on receiver */
+	uint32_t		m_parent_lkid;
+	uint32_t		m_parent_remid;
+	uint32_t		m_exflags;
+	uint32_t		m_sbflags;
+	uint32_t		m_flags;
+	uint32_t		m_lvbseq;
+	uint32_t		m_hash;
+	int			m_status;
+	int			m_grmode;
+	int			m_rqmode;
+	int			m_bastmode;
+	int			m_asts;
+	int			m_result;	/* 0 or -EXXX */
+	uint64_t		m_range[2];
+	char			m_extra[0];	/* name or lvb */
+};
+
+
+#define DLM_RS_NODES		0x00000001
+#define DLM_RS_NODES_ALL	0x00000002
+#define DLM_RS_DIR		0x00000004
+#define DLM_RS_DIR_ALL		0x00000008
+#define DLM_RS_LOCKS		0x00000010
+#define DLM_RS_LOCKS_ALL	0x00000020
+#define DLM_RS_DONE		0x00000040
+#define DLM_RS_DONE_ALL		0x00000080
+
+#define DLM_RCOM_STATUS		1
+#define DLM_RCOM_NAMES		2
+#define DLM_RCOM_LOOKUP		3
+#define DLM_RCOM_LOCK		4
+#define DLM_RCOM_STATUS_REPLY	5
+#define DLM_RCOM_NAMES_REPLY	6
+#define DLM_RCOM_LOOKUP_REPLY	7
+#define DLM_RCOM_LOCK_REPLY	8
+
+struct dlm_rcom {
+	struct dlm_header	rc_header;
+	uint32_t		rc_type;	/* DLM_RCOM_ */
+	int			rc_result;	/* multi-purpose */
+	uint64_t		rc_id;		/* match reply with request */
+	char			rc_buf[0];
+};
+
+struct rcom_config {
+	uint32_t		rf_lvblen;
+	uint32_t		rf_lsflags;
+	uint64_t		rf_unused;
+};
+
+struct rcom_lock {
+	uint32_t		rl_ownpid;
+	uint32_t		rl_lkid;
+	uint32_t		rl_remid;
+	uint32_t		rl_parent_lkid;
+	uint32_t		rl_parent_remid;
+	uint32_t		rl_exflags;
+	uint32_t		rl_flags;
+	uint32_t		rl_lvbseq;
+	int			rl_result;
+	int8_t			rl_rqmode;
+	int8_t			rl_grmode;
+	int8_t			rl_status;
+	int8_t			rl_asts;
+	uint16_t		rl_wait_type;
+	uint16_t		rl_namelen;
+	uint64_t		rl_range[4];
+	char			rl_name[DLM_RESNAME_MAXLEN];
+	char			rl_lvb[0];
+};
+
+struct dlm_ls {
+	struct list_head	ls_list;	/* list of lockspaces */
+	uint32_t		ls_global_id;	/* global unique lockspace ID */
+	uint32_t		ls_exflags;
+	int			ls_lvblen;
+	int			ls_count;	/* reference count */
+	unsigned long		ls_flags;	/* LSFL_ */
+	struct kobject		ls_kobj;
+
+	struct dlm_rsbtable	*ls_rsbtbl;
+	uint32_t		ls_rsbtbl_size;
+
+	struct dlm_lkbtable	*ls_lkbtbl;
+	uint32_t		ls_lkbtbl_size;
+
+	struct dlm_dirtable	*ls_dirtbl;
+	uint32_t		ls_dirtbl_size;
+
+	struct semaphore	ls_waiters_sem;
+	struct list_head	ls_waiters;	/* lkbs needing a reply */
+
+	struct list_head	ls_nodes;	/* current nodes in ls */
+	struct list_head	ls_nodes_gone;	/* dead node list, recovery */
+	int			ls_num_nodes;	/* number of nodes in ls */
+	int			ls_low_nodeid;
+	int			ls_total_weight;
+	int			*ls_node_array;
+
+	struct dlm_rsb		ls_stub_rsb;	/* for returning errors */
+	struct dlm_lkb		ls_stub_lkb;	/* for returning errors */
+	struct dlm_message	ls_stub_ms;	/* for faking a reply */
+
+	struct dentry		*ls_debug_dentry; /* debugfs */
+
+	wait_queue_head_t	ls_uevent_wait;	/* user part of join/leave */
+	int			ls_uevent_result;
+
+	/* recovery related */
+
+	struct timer_list	ls_timer;
+	struct task_struct	*ls_recoverd_task;
+	struct semaphore	ls_recoverd_active;
+	spinlock_t		ls_recover_lock;
+	uint32_t		ls_recover_status; /* DLM_RS_ */
+	uint64_t		ls_recover_seq;
+	struct dlm_recover	*ls_recover_args;
+	struct rw_semaphore	ls_in_recovery;	/* block local requests */
+	struct list_head	ls_requestqueue;/* queue remote requests */
+	struct semaphore	ls_requestqueue_lock;
+	char			*ls_recover_buf;
+	struct list_head	ls_recover_list;
+	spinlock_t		ls_recover_list_lock;
+	int			ls_recover_list_count;
+	wait_queue_head_t	ls_wait_general;
+
+	struct list_head	ls_root_list;	/* root resources */
+	struct rw_semaphore	ls_root_sem;	/* protect root_list */
+
+	int			ls_namelen;
+	char			ls_name[1];
+};
+
+#define LSFL_WORK		0
+#define LSFL_RUNNING		1
+#define LSFL_RECOVERY_STOP	2
+#define LSFL_RCOM_READY		3
+#define LSFL_UEVENT_WAIT	4
+
+static inline int dlm_locking_stopped(struct dlm_ls *ls)
+{
+	return !test_bit(LSFL_RUNNING, &ls->ls_flags);
+}
+
+static inline int dlm_recovery_stopped(struct dlm_ls *ls)
+{
+	return test_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
+}
+
+static inline int dlm_no_directory(struct dlm_ls *ls)
+{
+	return (ls->ls_exflags & DLM_LSFL_NODIR) ? 1 : 0;
+}
+
+#endif				/* __DLM_INTERNAL_DOT_H__ */
+

fs/dlm/lock.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+/* Central locking logic has four stages:
+
+   dlm_lock()
+   dlm_unlock()
+
+   request_lock(ls, lkb)
+   convert_lock(ls, lkb)
+   unlock_lock(ls, lkb)
+   cancel_lock(ls, lkb)
+
+   _request_lock(r, lkb)
+   _convert_lock(r, lkb)
+   _unlock_lock(r, lkb)
+   _cancel_lock(r, lkb)
+
+   do_request(r, lkb)
+   do_convert(r, lkb)
+   do_unlock(r, lkb)
+   do_cancel(r, lkb)
+
+   Stage 1 (lock, unlock) is mainly about checking input args and
+   splitting into one of the four main operations:
+
+       dlm_lock          = request_lock
+       dlm_lock+CONVERT  = convert_lock
+       dlm_unlock        = unlock_lock
+       dlm_unlock+CANCEL = cancel_lock
+
+   Stage 2, xxxx_lock(), just finds and locks the relevant rsb which is
+   provided to the next stage.
+
+   Stage 3, _xxxx_lock(), determines if the operation is local or remote.
+   When remote, it calls send_xxxx(), when local it calls do_xxxx().
+
+   Stage 4, do_xxxx(), is the guts of the operation.  It manipulates the
+   given rsb and lkb and queues callbacks.
+
+   For remote operations, send_xxxx() results in the corresponding do_xxxx()
+   function being executed on the remote node.  The connecting send/receive
+   calls on local (L) and remote (R) nodes:
+
+   L: send_xxxx()              ->  R: receive_xxxx()
+                                   R: do_xxxx()
+   L: receive_xxxx_reply()     <-  R: send_xxxx_reply()
+*/
+
+#include "dlm_internal.h"
+#include "memory.h"
+#include "lowcomms.h"
+#include "requestqueue.h"
+#include "util.h"
+#include "dir.h"
+#include "member.h"
+#include "lockspace.h"
+#include "ast.h"
+#include "lock.h"
+#include "rcom.h"
+#include "recover.h"
+#include "lvb_table.h"
+#include "config.h"
+
+static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode);
+static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static int send_remove(struct dlm_rsb *r);
+static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
+static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
+				    struct dlm_message *ms);
+static int receive_extralen(struct dlm_message *ms);
+
+/*
+ * Lock compatibilty matrix - thanks Steve
+ * UN = Unlocked state. Not really a state, used as a flag
+ * PD = Padding. Used to make the matrix a nice power of two in size
+ * Other states are the same as the VMS DLM.
+ * Usage: matrix[grmode+1][rqmode+1]  (although m[rq+1][gr+1] is the same)
+ */
+
+static const int __dlm_compat_matrix[8][8] = {
+      /* UN NL CR CW PR PW EX PD */
+        {1, 1, 1, 1, 1, 1, 1, 0},       /* UN */
+        {1, 1, 1, 1, 1, 1, 1, 0},       /* NL */
+        {1, 1, 1, 1, 1, 1, 0, 0},       /* CR */
+        {1, 1, 1, 1, 0, 0, 0, 0},       /* CW */
+        {1, 1, 1, 0, 1, 0, 0, 0},       /* PR */
+        {1, 1, 1, 0, 0, 0, 0, 0},       /* PW */
+        {1, 1, 0, 0, 0, 0, 0, 0},       /* EX */
+        {0, 0, 0, 0, 0, 0, 0, 0}        /* PD */
+};
+
+/*
+ * This defines the direction of transfer of LVB data.
+ * Granted mode is the row; requested mode is the column.
+ * Usage: matrix[grmode+1][rqmode+1]
+ * 1 = LVB is returned to the caller
+ * 0 = LVB is written to the resource
+ * -1 = nothing happens to the LVB
+ */
+
+const int dlm_lvb_operations[8][8] = {
+        /* UN   NL  CR  CW  PR  PW  EX  PD*/
+        {  -1,  1,  1,  1,  1,  1,  1, -1 }, /* UN */
+        {  -1,  1,  1,  1,  1,  1,  1,  0 }, /* NL */
+        {  -1, -1,  1,  1,  1,  1,  1,  0 }, /* CR */
+        {  -1, -1, -1,  1,  1,  1,  1,  0 }, /* CW */
+        {  -1, -1, -1, -1,  1,  1,  1,  0 }, /* PR */
+        {  -1,  0,  0,  0,  0,  0,  1,  0 }, /* PW */
+        {  -1,  0,  0,  0,  0,  0,  0,  0 }, /* EX */
+        {  -1,  0,  0,  0,  0,  0,  0,  0 }  /* PD */
+};
+EXPORT_SYMBOL_GPL(dlm_lvb_operations);
+
+#define modes_compat(gr, rq) \
+	__dlm_compat_matrix[(gr)->lkb_grmode + 1][(rq)->lkb_rqmode + 1]
+
+int dlm_modes_compat(int mode1, int mode2)
+{
+	return __dlm_compat_matrix[mode1 + 1][mode2 + 1];
+}
+
+/*
+ * Compatibility matrix for conversions with QUECVT set.
+ * Granted mode is the row; requested mode is the column.
+ * Usage: matrix[grmode+1][rqmode+1]
+ */
+
+static const int __quecvt_compat_matrix[8][8] = {
+      /* UN NL CR CW PR PW EX PD */
+        {0, 0, 0, 0, 0, 0, 0, 0},       /* UN */
+        {0, 0, 1, 1, 1, 1, 1, 0},       /* NL */
+        {0, 0, 0, 1, 1, 1, 1, 0},       /* CR */
+        {0, 0, 0, 0, 1, 1, 1, 0},       /* CW */
+        {0, 0, 0, 1, 0, 1, 1, 0},       /* PR */
+        {0, 0, 0, 0, 0, 0, 1, 0},       /* PW */
+        {0, 0, 0, 0, 0, 0, 0, 0},       /* EX */
+        {0, 0, 0, 0, 0, 0, 0, 0}        /* PD */
+};
+
+static void dlm_print_lkb(struct dlm_lkb *lkb)
+{
+	printk(KERN_ERR "lkb: nodeid %d id %x remid %x exflags %x flags %x\n"
+	       "     status %d rqmode %d grmode %d wait_type %d ast_type %d\n",
+	       lkb->lkb_nodeid, lkb->lkb_id, lkb->lkb_remid, lkb->lkb_exflags,
+	       lkb->lkb_flags, lkb->lkb_status, lkb->lkb_rqmode,
+	       lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_ast_type);
+}
+
+void dlm_print_rsb(struct dlm_rsb *r)
+{
+	printk(KERN_ERR "rsb: nodeid %d flags %lx first %x rlc %d name %s\n",
+	       r->res_nodeid, r->res_flags, r->res_first_lkid,
+	       r->res_recover_locks_count, r->res_name);
+}
+
+/* Threads cannot use the lockspace while it's being recovered */
+
+static inline void lock_recovery(struct dlm_ls *ls)
+{
+	down_read(&ls->ls_in_recovery);
+}
+
+static inline void unlock_recovery(struct dlm_ls *ls)
+{
+	up_read(&ls->ls_in_recovery);
+}
+
+static inline int lock_recovery_try(struct dlm_ls *ls)
+{
+	return down_read_trylock(&ls->ls_in_recovery);
+}
+
+static inline int can_be_queued(struct dlm_lkb *lkb)
+{
+	return !(lkb->lkb_exflags & DLM_LKF_NOQUEUE);
+}
+
+static inline int force_blocking_asts(struct dlm_lkb *lkb)
+{
+	return (lkb->lkb_exflags & DLM_LKF_NOQUEUEBAST);
+}
+
+static inline int is_demoted(struct dlm_lkb *lkb)
+{
+	return (lkb->lkb_sbflags & DLM_SBF_DEMOTED);
+}
+
+static inline int is_remote(struct dlm_rsb *r)
+{
+	DLM_ASSERT(r->res_nodeid >= 0, dlm_print_rsb(r););
+	return !!r->res_nodeid;
+}
+
+static inline int is_process_copy(struct dlm_lkb *lkb)
+{
+	return (lkb->lkb_nodeid && !(lkb->lkb_flags & DLM_IFL_MSTCPY));
+}
+
+static inline int is_master_copy(struct dlm_lkb *lkb)
+{
+	if (lkb->lkb_flags & DLM_IFL_MSTCPY)
+		DLM_ASSERT(lkb->lkb_nodeid, dlm_print_lkb(lkb););
+	return (lkb->lkb_flags & DLM_IFL_MSTCPY) ? TRUE : FALSE;
+}
+
+static inline int middle_conversion(struct dlm_lkb *lkb)
+{
+	if ((lkb->lkb_grmode==DLM_LOCK_PR && lkb->lkb_rqmode==DLM_LOCK_CW) ||
+	    (lkb->lkb_rqmode==DLM_LOCK_PR && lkb->lkb_grmode==DLM_LOCK_CW))
+		return TRUE;
+	return FALSE;
+}
+
+static inline int down_conversion(struct dlm_lkb *lkb)
+{
+	return (!middle_conversion(lkb) && lkb->lkb_rqmode < lkb->lkb_grmode);
+}
+
+static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
+{
+	if (is_master_copy(lkb))
+		return;
+
+	DLM_ASSERT(lkb->lkb_lksb, dlm_print_lkb(lkb););
+
+	lkb->lkb_lksb->sb_status = rv;
+	lkb->lkb_lksb->sb_flags = lkb->lkb_sbflags;
+
+	dlm_add_ast(lkb, AST_COMP);
+}
+
+static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
+{
+	if (is_master_copy(lkb))
+		send_bast(r, lkb, rqmode);
+	else {
+		lkb->lkb_bastmode = rqmode;
+		dlm_add_ast(lkb, AST_BAST);
+	}
+}
+
+/*
+ * Basic operations on rsb's and lkb's
+ */
+
+static struct dlm_rsb *create_rsb(struct dlm_ls *ls, char *name, int len)
+{
+	struct dlm_rsb *r;
+
+	r = allocate_rsb(ls, len);
+	if (!r)
+		return NULL;
+
+	r->res_ls = ls;
+	r->res_length = len;
+	memcpy(r->res_name, name, len);
+	init_MUTEX(&r->res_sem);
+
+	INIT_LIST_HEAD(&r->res_lookup);
+	INIT_LIST_HEAD(&r->res_grantqueue);
+	INIT_LIST_HEAD(&r->res_convertqueue);
+	INIT_LIST_HEAD(&r->res_waitqueue);
+	INIT_LIST_HEAD(&r->res_root_list);
+	INIT_LIST_HEAD(&r->res_recover_list);
+
+	return r;
+}
+
+static int search_rsb_list(struct list_head *head, char *name, int len,
+			   unsigned int flags, struct dlm_rsb **r_ret)
+{
+	struct dlm_rsb *r;
+	int error = 0;
+
+	list_for_each_entry(r, head, res_hashchain) {
+		if (len == r->res_length && !memcmp(name, r->res_name, len))
+			goto found;
+	}
+	return -ENOENT;
+
+ found:
+	if (r->res_nodeid && (flags & R_MASTER))
+		error = -ENOTBLK;
+	*r_ret = r;
+	return error;
+}
+
+static int _search_rsb(struct dlm_ls *ls, char *name, int len, int b,
+		       unsigned int flags, struct dlm_rsb **r_ret)
+{
+	struct dlm_rsb *r;
+	int error;
+
+	error = search_rsb_list(&ls->ls_rsbtbl[b].list, name, len, flags, &r);
+	if (!error) {
+		kref_get(&r->res_ref);
+		goto out;
+	}
+	error = search_rsb_list(&ls->ls_rsbtbl[b].toss, name, len, flags, &r);
+	if (error)
+		goto out;
+
+	list_move(&r->res_hashchain, &ls->ls_rsbtbl[b].list);
+
+	if (dlm_no_directory(ls))
+		goto out;
+
+	if (r->res_nodeid == -1) {
+		rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
+		r->res_first_lkid = 0;
+	} else if (r->res_nodeid > 0) {
+		rsb_set_flag(r, RSB_MASTER_UNCERTAIN);
+		r->res_first_lkid = 0;
+	} else {
+		DLM_ASSERT(r->res_nodeid == 0, dlm_print_rsb(r););
+		DLM_ASSERT(!rsb_flag(r, RSB_MASTER_UNCERTAIN),);
+	}
+ out:
+	*r_ret = r;
+	return error;
+}
+
+static int search_rsb(struct dlm_ls *ls, char *name, int len, int b,
+		      unsigned int flags, struct dlm_rsb **r_ret)
+{
+	int error;
+	write_lock(&ls->ls_rsbtbl[b].lock);
+	error = _search_rsb(ls, name, len, b, flags, r_ret);
+	write_unlock(&ls->ls_rsbtbl[b].lock);
+	return error;
+}
+
+/*
+ * Find rsb in rsbtbl and potentially create/add one
+ *
+ * Delaying the release of rsb's has a similar benefit to applications keeping
+ * NL locks on an rsb, but without the guarantee that the cached master value
+ * will still be valid when the rsb is reused.  Apps aren't always smart enough
+ * to keep NL locks on an rsb that they may lock again shortly; this can lead
+ * to excessive master lookups and removals if we don't delay the release.
+ *
+ * Searching for an rsb means looking through both the normal list and toss
+ * list.  When found on the toss list the rsb is moved to the normal list with
+ * ref count of 1; when found on normal list the ref count is incremented.
+ */
+
+static int find_rsb(struct dlm_ls *ls, char *name, int namelen,
+		    unsigned int flags, struct dlm_rsb **r_ret)
+{
+	struct dlm_rsb *r, *tmp;
+	uint32_t hash, bucket;
+	int error = 0;
+
+	if (dlm_no_directory(ls))
+		flags |= R_CREATE;
+
+	hash = jhash(name, namelen, 0);
+	bucket = hash & (ls->ls_rsbtbl_size - 1);
+
+	error = search_rsb(ls, name, namelen, bucket, flags, &r);
+	if (!error)
+		goto out;
+
+	if (error == -ENOENT && !(flags & R_CREATE))
+		goto out;
+
+	/* the rsb was found but wasn't a master copy */
+	if (error == -ENOTBLK)
+		goto out;
+
+	error = -ENOMEM;
+	r = create_rsb(ls, name, namelen);
+	if (!r)
+		goto out;
+
+	r->res_hash = hash;
+	r->res_bucket = bucket;
+	r->res_nodeid = -1;
+	kref_init(&r->res_ref);
+
+	/* With no directory, the master can be set immediately */
+	if (dlm_no_directory(ls)) {
+		int nodeid = dlm_dir_nodeid(r);
+		if (nodeid == dlm_our_nodeid())
+			nodeid = 0;
+		r->res_nodeid = nodeid;
+	}
+
+	write_lock(&ls->ls_rsbtbl[bucket].lock);
+	error = _search_rsb(ls, name, namelen, bucket, 0, &tmp);
+	if (!error) {
+		write_unlock(&ls->ls_rsbtbl[bucket].lock);
+		free_rsb(r);
+		r = tmp;
+		goto out;
+	}
+	list_add(&r->res_hashchain, &ls->ls_rsbtbl[bucket].list);
+	write_unlock(&ls->ls_rsbtbl[bucket].lock);
+	error = 0;
+ out:
+	*r_ret = r;
+	return error;
+}
+
+int dlm_find_rsb(struct dlm_ls *ls, char *name, int namelen,
+		 unsigned int flags, struct dlm_rsb **r_ret)
+{
+	return find_rsb(ls, name, namelen, flags, r_ret);
+}
+
+/* This is only called to add a reference when the code already holds
+   a valid reference to the rsb, so there's no need for locking. */
+
+static inline void hold_rsb(struct dlm_rsb *r)
+{
+	kref_get(&r->res_ref);
+}
+
+void dlm_hold_rsb(struct dlm_rsb *r)
+{
+	hold_rsb(r);
+}
+
+static void toss_rsb(struct kref *kref)
+{
+	struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref);
+	struct dlm_ls *ls = r->res_ls;
+
+	DLM_ASSERT(list_empty(&r->res_root_list), dlm_print_rsb(r););
+	kref_init(&r->res_ref);
+	list_move(&r->res_hashchain, &ls->ls_rsbtbl[r->res_bucket].toss);
+	r->res_toss_time = jiffies;
+	if (r->res_lvbptr) {
+		free_lvb(r->res_lvbptr);
+		r->res_lvbptr = NULL;
+	}
+}
+
+/* When all references to the rsb are gone it's transfered to
+   the tossed list for later disposal. */
+
+static void put_rsb(struct dlm_rsb *r)
+{
+	struct dlm_ls *ls = r->res_ls;
+	uint32_t bucket = r->res_bucket;
+
+	write_lock(&ls->ls_rsbtbl[bucket].lock);
+	kref_put(&r->res_ref, toss_rsb);
+	write_unlock(&ls->ls_rsbtbl[bucket].lock);
+}
+
+void dlm_put_rsb(struct dlm_rsb *r)
+{
+	put_rsb(r);
+}
+
+/* See comment for unhold_lkb */
+
+static void unhold_rsb(struct dlm_rsb *r)
+{
+	int rv;
+	rv = kref_put(&r->res_ref, toss_rsb);
+	DLM_ASSERT(!rv, dlm_print_rsb(r););
+}
+
+static void kill_rsb(struct kref *kref)
+{
+	struct dlm_rsb *r = container_of(kref, struct dlm_rsb, res_ref);
+
+	/* All work is done after the return from kref_put() so we
+	   can release the write_lock before the remove and free. */
+
+	DLM_ASSERT(list_empty(&r->res_lookup),);
+	DLM_ASSERT(list_empty(&r->res_grantqueue),);
+	DLM_ASSERT(list_empty(&r->res_convertqueue),);
+	DLM_ASSERT(list_empty(&r->res_waitqueue),);
+	DLM_ASSERT(list_empty(&r->res_root_list),);
+	DLM_ASSERT(list_empty(&r->res_recover_list),);
+}
+
+/* Attaching/detaching lkb's from rsb's is for rsb reference counting.
+   The rsb must exist as long as any lkb's for it do. */
+
+static void attach_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	hold_rsb(r);
+	lkb->lkb_resource = r;
+}
+
+static void detach_lkb(struct dlm_lkb *lkb)
+{
+	if (lkb->lkb_resource) {
+		put_rsb(lkb->lkb_resource);
+		lkb->lkb_resource = NULL;
+	}
+}
+
+static int create_lkb(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
+{
+	struct dlm_lkb *lkb, *tmp;
+	uint32_t lkid = 0;
+	uint16_t bucket;
+
+	lkb = allocate_lkb(ls);
+	if (!lkb)
+		return -ENOMEM;
+
+	lkb->lkb_nodeid = -1;
+	lkb->lkb_grmode = DLM_LOCK_IV;
+	kref_init(&lkb->lkb_ref);
+
+	get_random_bytes(&bucket, sizeof(bucket));
+	bucket &= (ls->ls_lkbtbl_size - 1);
+
+	write_lock(&ls->ls_lkbtbl[bucket].lock);
+
+	/* counter can roll over so we must verify lkid is not in use */
+
+	while (lkid == 0) {
+		lkid = bucket | (ls->ls_lkbtbl[bucket].counter++ << 16);
+
+		list_for_each_entry(tmp, &ls->ls_lkbtbl[bucket].list,
+				    lkb_idtbl_list) {
+			if (tmp->lkb_id != lkid)
+				continue;
+			lkid = 0;
+			break;
+		}
+	}
+
+	lkb->lkb_id = lkid;
+	list_add(&lkb->lkb_idtbl_list, &ls->ls_lkbtbl[bucket].list);
+	write_unlock(&ls->ls_lkbtbl[bucket].lock);
+
+	*lkb_ret = lkb;
+	return 0;
+}
+
+static struct dlm_lkb *__find_lkb(struct dlm_ls *ls, uint32_t lkid)
+{
+	uint16_t bucket = lkid & 0xFFFF;
+	struct dlm_lkb *lkb;
+
+	list_for_each_entry(lkb, &ls->ls_lkbtbl[bucket].list, lkb_idtbl_list) {
+		if (lkb->lkb_id == lkid)
+			return lkb;
+	}
+	return NULL;
+}
+
+static int find_lkb(struct dlm_ls *ls, uint32_t lkid, struct dlm_lkb **lkb_ret)
+{
+	struct dlm_lkb *lkb;
+	uint16_t bucket = lkid & 0xFFFF;
+
+	if (bucket >= ls->ls_lkbtbl_size)
+		return -EBADSLT;
+
+	read_lock(&ls->ls_lkbtbl[bucket].lock);
+	lkb = __find_lkb(ls, lkid);
+	if (lkb)
+		kref_get(&lkb->lkb_ref);
+	read_unlock(&ls->ls_lkbtbl[bucket].lock);
+
+	*lkb_ret = lkb;
+	return lkb ? 0 : -ENOENT;
+}
+
+static void kill_lkb(struct kref *kref)
+{
+	struct dlm_lkb *lkb = container_of(kref, struct dlm_lkb, lkb_ref);
+
+	/* All work is done after the return from kref_put() so we
+	   can release the write_lock before the detach_lkb */
+
+	DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb););
+}
+
+static int put_lkb(struct dlm_lkb *lkb)
+{
+	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+	uint16_t bucket = lkb->lkb_id & 0xFFFF;
+
+	write_lock(&ls->ls_lkbtbl[bucket].lock);
+	if (kref_put(&lkb->lkb_ref, kill_lkb)) {
+		list_del(&lkb->lkb_idtbl_list);
+		write_unlock(&ls->ls_lkbtbl[bucket].lock);
+
+		detach_lkb(lkb);
+
+		/* for local/process lkbs, lvbptr points to caller's lksb */
+		if (lkb->lkb_lvbptr && is_master_copy(lkb))
+			free_lvb(lkb->lkb_lvbptr);
+		if (lkb->lkb_range)
+			free_range(lkb->lkb_range);
+		free_lkb(lkb);
+		return 1;
+	} else {
+		write_unlock(&ls->ls_lkbtbl[bucket].lock);
+		return 0;
+	}
+}
+
+int dlm_put_lkb(struct dlm_lkb *lkb)
+{
+	return put_lkb(lkb);
+}
+
+/* This is only called to add a reference when the code already holds
+   a valid reference to the lkb, so there's no need for locking. */
+
+static inline void hold_lkb(struct dlm_lkb *lkb)
+{
+	kref_get(&lkb->lkb_ref);
+}
+
+/* This is called when we need to remove a reference and are certain
+   it's not the last ref.  e.g. del_lkb is always called between a
+   find_lkb/put_lkb and is always the inverse of a previous add_lkb.
+   put_lkb would work fine, but would involve unnecessary locking */
+
+static inline void unhold_lkb(struct dlm_lkb *lkb)
+{
+	int rv;
+	rv = kref_put(&lkb->lkb_ref, kill_lkb);
+	DLM_ASSERT(!rv, dlm_print_lkb(lkb););
+}
+
+static void lkb_add_ordered(struct list_head *new, struct list_head *head,
+			    int mode)
+{
+	struct dlm_lkb *lkb = NULL;
+
+	list_for_each_entry(lkb, head, lkb_statequeue)
+		if (lkb->lkb_rqmode < mode)
+			break;
+
+	if (!lkb)
+		list_add_tail(new, head);
+	else
+		__list_add(new, lkb->lkb_statequeue.prev, &lkb->lkb_statequeue);
+}
+
+/* add/remove lkb to rsb's grant/convert/wait queue */
+
+static void add_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb, int status)
+{
+	kref_get(&lkb->lkb_ref);
+
+	DLM_ASSERT(!lkb->lkb_status, dlm_print_lkb(lkb););
+
+	lkb->lkb_status = status;
+
+	switch (status) {
+	case DLM_LKSTS_WAITING:
+		if (lkb->lkb_exflags & DLM_LKF_HEADQUE)
+			list_add(&lkb->lkb_statequeue, &r->res_waitqueue);
+		else
+			list_add_tail(&lkb->lkb_statequeue, &r->res_waitqueue);
+		break;
+	case DLM_LKSTS_GRANTED:
+		/* convention says granted locks kept in order of grmode */
+		lkb_add_ordered(&lkb->lkb_statequeue, &r->res_grantqueue,
+				lkb->lkb_grmode);
+		break;
+	case DLM_LKSTS_CONVERT:
+		if (lkb->lkb_exflags & DLM_LKF_HEADQUE)
+			list_add(&lkb->lkb_statequeue, &r->res_convertqueue);
+		else
+			list_add_tail(&lkb->lkb_statequeue,
+				      &r->res_convertqueue);
+		break;
+	default:
+		DLM_ASSERT(0, dlm_print_lkb(lkb); printk("sts=%d\n", status););
+	}
+}
+
+static void del_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	lkb->lkb_status = 0;
+	list_del(&lkb->lkb_statequeue);
+	unhold_lkb(lkb);
+}
+
+static void move_lkb(struct dlm_rsb *r, struct dlm_lkb *lkb, int sts)
+{
+	hold_lkb(lkb);
+	del_lkb(r, lkb);
+	add_lkb(r, lkb, sts);
+	unhold_lkb(lkb);
+}
+
+/* add/remove lkb from global waiters list of lkb's waiting for
+   a reply from a remote node */
+
+static void add_to_waiters(struct dlm_lkb *lkb, int mstype)
+{
+	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+
+	down(&ls->ls_waiters_sem);
+	if (lkb->lkb_wait_type) {
+		log_print("add_to_waiters error %d", lkb->lkb_wait_type);
+		goto out;
+	}
+	lkb->lkb_wait_type = mstype;
+	kref_get(&lkb->lkb_ref);
+	list_add(&lkb->lkb_wait_reply, &ls->ls_waiters);
+ out:
+	up(&ls->ls_waiters_sem);
+}
+
+static int _remove_from_waiters(struct dlm_lkb *lkb)
+{
+	int error = 0;
+
+	if (!lkb->lkb_wait_type) {
+		log_print("remove_from_waiters error");
+		error = -EINVAL;
+		goto out;
+	}
+	lkb->lkb_wait_type = 0;
+	list_del(&lkb->lkb_wait_reply);
+	unhold_lkb(lkb);
+ out:
+	return error;
+}
+
+static int remove_from_waiters(struct dlm_lkb *lkb)
+{
+	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
+	int error;
+
+	down(&ls->ls_waiters_sem);
+	error = _remove_from_waiters(lkb);
+	up(&ls->ls_waiters_sem);
+	return error;
+}
+
+static void dir_remove(struct dlm_rsb *r)
+{
+	int to_nodeid;
+
+	if (dlm_no_directory(r->res_ls))
+		return;
+
+	to_nodeid = dlm_dir_nodeid(r);
+	if (to_nodeid != dlm_our_nodeid())
+		send_remove(r);
+	else
+		dlm_dir_remove_entry(r->res_ls, to_nodeid,
+				     r->res_name, r->res_length);
+}
+
+/* FIXME: shouldn't this be able to exit as soon as one non-due rsb is
+   found since they are in order of newest to oldest? */
+
+static int shrink_bucket(struct dlm_ls *ls, int b)
+{
+	struct dlm_rsb *r;
+	int count = 0, found;
+
+	for (;;) {
+		found = FALSE;
+		write_lock(&ls->ls_rsbtbl[b].lock);
+		list_for_each_entry_reverse(r, &ls->ls_rsbtbl[b].toss,
+					    res_hashchain) {
+			if (!time_after_eq(jiffies, r->res_toss_time +
+					   dlm_config.toss_secs * HZ))
+				continue;
+			found = TRUE;
+			break;
+		}
+
+		if (!found) {
+			write_unlock(&ls->ls_rsbtbl[b].lock);
+			break;
+		}
+
+		if (kref_put(&r->res_ref, kill_rsb)) {
+			list_del(&r->res_hashchain);
+			write_unlock(&ls->ls_rsbtbl[b].lock);
+
+			if (is_master(r))
+				dir_remove(r);
+			free_rsb(r);
+			count++;
+		} else {
+			write_unlock(&ls->ls_rsbtbl[b].lock);
+			log_error(ls, "tossed rsb in use %s", r->res_name);
+		}
+	}
+
+	return count;
+}
+
+void dlm_scan_rsbs(struct dlm_ls *ls)
+{
+	int i;
+
+	if (dlm_locking_stopped(ls))
+		return;
+
+	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
+		shrink_bucket(ls, i);
+		cond_resched();
+	}
+}
+
+/* lkb is master or local copy */
+
+static void set_lvb_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int b, len = r->res_ls->ls_lvblen;
+
+	/* b=1 lvb returned to caller
+	   b=0 lvb written to rsb or invalidated
+	   b=-1 do nothing */
+
+	b =  dlm_lvb_operations[lkb->lkb_grmode + 1][lkb->lkb_rqmode + 1];
+
+	if (b == 1) {
+		if (!lkb->lkb_lvbptr)
+			return;
+
+		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
+			return;
+
+		if (!r->res_lvbptr)
+			return;
+
+		memcpy(lkb->lkb_lvbptr, r->res_lvbptr, len);
+		lkb->lkb_lvbseq = r->res_lvbseq;
+
+	} else if (b == 0) {
+		if (lkb->lkb_exflags & DLM_LKF_IVVALBLK) {
+			rsb_set_flag(r, RSB_VALNOTVALID);
+			return;
+		}
+
+		if (!lkb->lkb_lvbptr)
+			return;
+
+		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
+			return;
+
+		if (!r->res_lvbptr)
+			r->res_lvbptr = allocate_lvb(r->res_ls);
+
+		if (!r->res_lvbptr)
+			return;
+
+		memcpy(r->res_lvbptr, lkb->lkb_lvbptr, len);
+		r->res_lvbseq++;
+		lkb->lkb_lvbseq = r->res_lvbseq;
+		rsb_clear_flag(r, RSB_VALNOTVALID);
+	}
+
+	if (rsb_flag(r, RSB_VALNOTVALID))
+		lkb->lkb_sbflags |= DLM_SBF_VALNOTVALID;
+}
+
+static void set_lvb_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	if (lkb->lkb_grmode < DLM_LOCK_PW)
+		return;
+
+	if (lkb->lkb_exflags & DLM_LKF_IVVALBLK) {
+		rsb_set_flag(r, RSB_VALNOTVALID);
+		return;
+	}
+
+	if (!lkb->lkb_lvbptr)
+		return;
+
+	if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
+		return;
+
+	if (!r->res_lvbptr)
+		r->res_lvbptr = allocate_lvb(r->res_ls);
+
+	if (!r->res_lvbptr)
+		return;
+
+	memcpy(r->res_lvbptr, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
+	r->res_lvbseq++;
+	rsb_clear_flag(r, RSB_VALNOTVALID);
+}
+
+/* lkb is process copy (pc) */
+
+static void set_lvb_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb,
+			    struct dlm_message *ms)
+{
+	int b;
+
+	if (!lkb->lkb_lvbptr)
+		return;
+
+	if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
+		return;
+
+	b =  dlm_lvb_operations[lkb->lkb_grmode + 1][lkb->lkb_rqmode + 1];
+	if (b == 1) {
+		int len = receive_extralen(ms);
+		memcpy(lkb->lkb_lvbptr, ms->m_extra, len);
+		lkb->lkb_lvbseq = ms->m_lvbseq;
+	}
+}
+
+/* Manipulate lkb's on rsb's convert/granted/waiting queues
+   remove_lock -- used for unlock, removes lkb from granted
+   revert_lock -- used for cancel, moves lkb from convert to granted
+   grant_lock  -- used for request and convert, adds lkb to granted or
+                  moves lkb from convert or waiting to granted
+
+   Each of these is used for master or local copy lkb's.  There is
+   also a _pc() variation used to make the corresponding change on
+   a process copy (pc) lkb. */
+
+static void _remove_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	del_lkb(r, lkb);
+	lkb->lkb_grmode = DLM_LOCK_IV;
+	/* this unhold undoes the original ref from create_lkb()
+	   so this leads to the lkb being freed */
+	unhold_lkb(lkb);
+}
+
+static void remove_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	set_lvb_unlock(r, lkb);
+	_remove_lock(r, lkb);
+}
+
+static void remove_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	_remove_lock(r, lkb);
+}
+
+static void revert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	lkb->lkb_rqmode = DLM_LOCK_IV;
+
+	switch (lkb->lkb_status) {
+	case DLM_LKSTS_CONVERT:
+		move_lkb(r, lkb, DLM_LKSTS_GRANTED);
+		break;
+	case DLM_LKSTS_WAITING:
+		del_lkb(r, lkb);
+		lkb->lkb_grmode = DLM_LOCK_IV;
+		/* this unhold undoes the original ref from create_lkb()
+		   so this leads to the lkb being freed */
+		unhold_lkb(lkb);
+		break;
+	default:
+		log_print("invalid status for revert %d", lkb->lkb_status);
+	}
+}
+
+static void revert_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	revert_lock(r, lkb);
+}
+
+static void _grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	if (lkb->lkb_grmode != lkb->lkb_rqmode) {
+		lkb->lkb_grmode = lkb->lkb_rqmode;
+		if (lkb->lkb_status)
+			move_lkb(r, lkb, DLM_LKSTS_GRANTED);
+		else
+			add_lkb(r, lkb, DLM_LKSTS_GRANTED);
+	}
+
+	lkb->lkb_rqmode = DLM_LOCK_IV;
+
+	if (lkb->lkb_range) {
+		lkb->lkb_range[GR_RANGE_START] = lkb->lkb_range[RQ_RANGE_START];
+		lkb->lkb_range[GR_RANGE_END] = lkb->lkb_range[RQ_RANGE_END];
+	}
+}
+
+static void grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	set_lvb_lock(r, lkb);
+	_grant_lock(r, lkb);
+	lkb->lkb_highbast = 0;
+}
+
+static void grant_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb,
+			  struct dlm_message *ms)
+{
+	set_lvb_lock_pc(r, lkb, ms);
+	_grant_lock(r, lkb);
+}
+
+/* called by grant_pending_locks() which means an async grant message must
+   be sent to the requesting node in addition to granting the lock if the
+   lkb belongs to a remote node. */
+
+static void grant_lock_pending(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	grant_lock(r, lkb);
+	if (is_master_copy(lkb))
+		send_grant(r, lkb);
+	else
+		queue_cast(r, lkb, 0);
+}
+
+static inline int first_in_list(struct dlm_lkb *lkb, struct list_head *head)
+{
+	struct dlm_lkb *first = list_entry(head->next, struct dlm_lkb,
+					   lkb_statequeue);
+	if (lkb->lkb_id == first->lkb_id)
+		return TRUE;
+
+	return FALSE;
+}
+
+/* Return 1 if the locks' ranges overlap.  If the lkb has no range then it is
+   assumed to cover 0-ffffffff.ffffffff */
+
+static inline int ranges_overlap(struct dlm_lkb *lkb1, struct dlm_lkb *lkb2)
+{
+	if (!lkb1->lkb_range || !lkb2->lkb_range)
+		return TRUE;
+
+	if (lkb1->lkb_range[RQ_RANGE_END] < lkb2->lkb_range[GR_RANGE_START] ||
+	    lkb1->lkb_range[RQ_RANGE_START] > lkb2->lkb_range[GR_RANGE_END])
+		return FALSE;
+
+	return TRUE;
+}
+
+/* Check if the given lkb conflicts with another lkb on the queue. */
+
+static int queue_conflict(struct list_head *head, struct dlm_lkb *lkb)
+{
+	struct dlm_lkb *this;
+
+	list_for_each_entry(this, head, lkb_statequeue) {
+		if (this == lkb)
+			continue;
+		if (ranges_overlap(lkb, this) && !modes_compat(this, lkb))
+			return TRUE;
+	}
+	return FALSE;
+}
+
+/*
+ * "A conversion deadlock arises with a pair of lock requests in the converting
+ * queue for one resource.  The granted mode of each lock blocks the requested
+ * mode of the other lock."
+ *
+ * Part 2: if the granted mode of lkb is preventing the first lkb in the
+ * convert queue from being granted, then demote lkb (set grmode to NL).
+ * This second form requires that we check for conv-deadlk even when
+ * now == 0 in _can_be_granted().
+ *
+ * Example:
+ * Granted Queue: empty
+ * Convert Queue: NL->EX (first lock)
+ *                PR->EX (second lock)
+ *
+ * The first lock can't be granted because of the granted mode of the second
+ * lock and the second lock can't be granted because it's not first in the
+ * list.  We demote the granted mode of the second lock (the lkb passed to this
+ * function).
+ *
+ * After the resolution, the "grant pending" function needs to go back and try
+ * to grant locks on the convert queue again since the first lock can now be
+ * granted.
+ */
+
+static int conversion_deadlock_detect(struct dlm_rsb *rsb, struct dlm_lkb *lkb)
+{
+	struct dlm_lkb *this, *first = NULL, *self = NULL;
+
+	list_for_each_entry(this, &rsb->res_convertqueue, lkb_statequeue) {
+		if (!first)
+			first = this;
+		if (this == lkb) {
+			self = lkb;
+			continue;
+		}
+
+		if (!ranges_overlap(lkb, this))
+			continue;
+
+		if (!modes_compat(this, lkb) && !modes_compat(lkb, this))
+			return TRUE;
+	}
+
+	/* if lkb is on the convert queue and is preventing the first
+	   from being granted, then there's deadlock and we demote lkb.
+	   multiple converting locks may need to do this before the first
+	   converting lock can be granted. */
+
+	if (self && self != first) {
+		if (!modes_compat(lkb, first) &&
+		    !queue_conflict(&rsb->res_grantqueue, first))
+			return TRUE;
+	}
+
+	return FALSE;
+}
+
+/*
+ * Return 1 if the lock can be granted, 0 otherwise.
+ * Also detect and resolve conversion deadlocks.
+ *
+ * lkb is the lock to be granted
+ *
+ * now is 1 if the function is being called in the context of the
+ * immediate request, it is 0 if called later, after the lock has been
+ * queued.
+ *
+ * References are from chapter 6 of "VAXcluster Principles" by Roy Davis
+ */
+
+static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
+{
+	int8_t conv = (lkb->lkb_grmode != DLM_LOCK_IV);
+
+	/*
+	 * 6-10: Version 5.4 introduced an option to address the phenomenon of
+	 * a new request for a NL mode lock being blocked.
+	 *
+	 * 6-11: If the optional EXPEDITE flag is used with the new NL mode
+	 * request, then it would be granted.  In essence, the use of this flag
+	 * tells the Lock Manager to expedite theis request by not considering
+	 * what may be in the CONVERTING or WAITING queues...  As of this
+	 * writing, the EXPEDITE flag can be used only with new requests for NL
+	 * mode locks.  This flag is not valid for conversion requests.
+	 *
+	 * A shortcut.  Earlier checks return an error if EXPEDITE is used in a
+	 * conversion or used with a non-NL requested mode.  We also know an
+	 * EXPEDITE request is always granted immediately, so now must always
+	 * be 1.  The full condition to grant an expedite request: (now &&
+	 * !conv && lkb->rqmode == DLM_LOCK_NL && (flags & EXPEDITE)) can
+	 * therefore be shortened to just checking the flag.
+	 */
+
+	if (lkb->lkb_exflags & DLM_LKF_EXPEDITE)
+		return TRUE;
+
+	/*
+	 * A shortcut. Without this, !queue_conflict(grantqueue, lkb) would be
+	 * added to the remaining conditions.
+	 */
+
+	if (queue_conflict(&r->res_grantqueue, lkb))
+		goto out;
+
+	/*
+	 * 6-3: By default, a conversion request is immediately granted if the
+	 * requested mode is compatible with the modes of all other granted
+	 * locks
+	 */
+
+	if (queue_conflict(&r->res_convertqueue, lkb))
+		goto out;
+
+	/*
+	 * 6-5: But the default algorithm for deciding whether to grant or
+	 * queue conversion requests does not by itself guarantee that such
+	 * requests are serviced on a "first come first serve" basis.  This, in
+	 * turn, can lead to a phenomenon known as "indefinate postponement".
+	 *
+	 * 6-7: This issue is dealt with by using the optional QUECVT flag with
+	 * the system service employed to request a lock conversion.  This flag
+	 * forces certain conversion requests to be queued, even if they are
+	 * compatible with the granted modes of other locks on the same
+	 * resource.  Thus, the use of this flag results in conversion requests
+	 * being ordered on a "first come first servce" basis.
+	 *
+	 * DCT: This condition is all about new conversions being able to occur
+	 * "in place" while the lock remains on the granted queue (assuming
+	 * nothing else conflicts.)  IOW if QUECVT isn't set, a conversion
+	 * doesn't _have_ to go onto the convert queue where it's processed in
+	 * order.  The "now" variable is necessary to distinguish converts
+	 * being received and processed for the first time now, because once a
+	 * convert is moved to the conversion queue the condition below applies
+	 * requiring fifo granting.
+	 */
+
+	if (now && conv && !(lkb->lkb_exflags & DLM_LKF_QUECVT))
+		return TRUE;
+
+	/*
+	 * When using range locks the NOORDER flag is set to avoid the standard
+	 * vms rules on grant order.
+	 */
+
+	if (lkb->lkb_exflags & DLM_LKF_NOORDER)
+		return TRUE;
+
+	/*
+	 * 6-3: Once in that queue [CONVERTING], a conversion request cannot be
+	 * granted until all other conversion requests ahead of it are granted
+	 * and/or canceled.
+	 */
+
+	if (!now && conv && first_in_list(lkb, &r->res_convertqueue))
+		return TRUE;
+
+	/*
+	 * 6-4: By default, a new request is immediately granted only if all
+	 * three of the following conditions are satisfied when the request is
+	 * issued:
+	 * - The queue of ungranted conversion requests for the resource is
+	 *   empty.
+	 * - The queue of ungranted new requests for the resource is empty.
+	 * - The mode of the new request is compatible with the most
+	 *   restrictive mode of all granted locks on the resource.
+	 */
+
+	if (now && !conv && list_empty(&r->res_convertqueue) &&
+	    list_empty(&r->res_waitqueue))
+		return TRUE;
+
+	/*
+	 * 6-4: Once a lock request is in the queue of ungranted new requests,
+	 * it cannot be granted until the queue of ungranted conversion
+	 * requests is empty, all ungranted new requests ahead of it are
+	 * granted and/or canceled, and it is compatible with the granted mode
+	 * of the most restrictive lock granted on the resource.
+	 */
+
+	if (!now && !conv && list_empty(&r->res_convertqueue) &&
+	    first_in_list(lkb, &r->res_waitqueue))
+		return TRUE;
+
+ out:
+	/*
+	 * The following, enabled by CONVDEADLK, departs from VMS.
+	 */
+
+	if (conv && (lkb->lkb_exflags & DLM_LKF_CONVDEADLK) &&
+	    conversion_deadlock_detect(r, lkb)) {
+		lkb->lkb_grmode = DLM_LOCK_NL;
+		lkb->lkb_sbflags |= DLM_SBF_DEMOTED;
+	}
+
+	return FALSE;
+}
+
+/*
+ * The ALTPR and ALTCW flags aren't traditional lock manager flags, but are a
+ * simple way to provide a big optimization to applications that can use them.
+ */
+
+static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
+{
+	uint32_t flags = lkb->lkb_exflags;
+	int rv;
+	int8_t alt = 0, rqmode = lkb->lkb_rqmode;
+
+	rv = _can_be_granted(r, lkb, now);
+	if (rv)
+		goto out;
+
+	if (lkb->lkb_sbflags & DLM_SBF_DEMOTED)
+		goto out;
+
+	if (rqmode != DLM_LOCK_PR && flags & DLM_LKF_ALTPR)
+		alt = DLM_LOCK_PR;
+	else if (rqmode != DLM_LOCK_CW && flags & DLM_LKF_ALTCW)
+		alt = DLM_LOCK_CW;
+
+	if (alt) {
+		lkb->lkb_rqmode = alt;
+		rv = _can_be_granted(r, lkb, now);
+		if (rv)
+			lkb->lkb_sbflags |= DLM_SBF_ALTMODE;
+		else
+			lkb->lkb_rqmode = rqmode;
+	}
+ out:
+	return rv;
+}
+
+static int grant_pending_convert(struct dlm_rsb *r, int high)
+{
+	struct dlm_lkb *lkb, *s;
+	int hi, demoted, quit, grant_restart, demote_restart;
+
+	quit = 0;
+ restart:
+	grant_restart = 0;
+	demote_restart = 0;
+	hi = DLM_LOCK_IV;
+
+	list_for_each_entry_safe(lkb, s, &r->res_convertqueue, lkb_statequeue) {
+		demoted = is_demoted(lkb);
+		if (can_be_granted(r, lkb, FALSE)) {
+			grant_lock_pending(r, lkb);
+			grant_restart = 1;
+		} else {
+			hi = max_t(int, lkb->lkb_rqmode, hi);
+			if (!demoted && is_demoted(lkb))
+				demote_restart = 1;
+		}
+	}
+
+	if (grant_restart)
+		goto restart;
+	if (demote_restart && !quit) {
+		quit = 1;
+		goto restart;
+	}
+
+	return max_t(int, high, hi);
+}
+
+static int grant_pending_wait(struct dlm_rsb *r, int high)
+{
+	struct dlm_lkb *lkb, *s;
+
+	list_for_each_entry_safe(lkb, s, &r->res_waitqueue, lkb_statequeue) {
+		if (can_be_granted(r, lkb, FALSE))
+			grant_lock_pending(r, lkb);
+                else
+			high = max_t(int, lkb->lkb_rqmode, high);
+	}
+
+	return high;
+}
+
+static void grant_pending_locks(struct dlm_rsb *r)
+{
+	struct dlm_lkb *lkb, *s;
+	int high = DLM_LOCK_IV;
+
+	DLM_ASSERT(is_master(r), dlm_print_rsb(r););
+
+	high = grant_pending_convert(r, high);
+	high = grant_pending_wait(r, high);
+
+	if (high == DLM_LOCK_IV)
+		return;
+
+	/*
+	 * If there are locks left on the wait/convert queue then send blocking
+	 * ASTs to granted locks based on the largest requested mode (high)
+	 * found above.  This can generate spurious blocking ASTs for range
+	 * locks. FIXME: highbast < high comparison not valid for PR/CW.
+	 */
+
+	list_for_each_entry_safe(lkb, s, &r->res_grantqueue, lkb_statequeue) {
+		if (lkb->lkb_bastaddr && (lkb->lkb_highbast < high) &&
+		    !__dlm_compat_matrix[lkb->lkb_grmode+1][high+1]) {
+			queue_bast(r, lkb, high);
+			lkb->lkb_highbast = high;
+		}
+	}
+}
+
+static void send_bast_queue(struct dlm_rsb *r, struct list_head *head,
+			    struct dlm_lkb *lkb)
+{
+	struct dlm_lkb *gr;
+
+	list_for_each_entry(gr, head, lkb_statequeue) {
+		if (gr->lkb_bastaddr &&
+		    gr->lkb_highbast < lkb->lkb_rqmode &&
+		    ranges_overlap(lkb, gr) && !modes_compat(gr, lkb)) {
+			queue_bast(r, gr, lkb->lkb_rqmode);
+			gr->lkb_highbast = lkb->lkb_rqmode;
+		}
+	}
+}
+
+static void send_blocking_asts(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	send_bast_queue(r, &r->res_grantqueue, lkb);
+}
+
+static void send_blocking_asts_all(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	send_bast_queue(r, &r->res_grantqueue, lkb);
+	send_bast_queue(r, &r->res_convertqueue, lkb);
+}
+
+/* set_master(r, lkb) -- set the master nodeid of a resource
+
+   The purpose of this function is to set the nodeid field in the given
+   lkb using the nodeid field in the given rsb.  If the rsb's nodeid is
+   known, it can just be copied to the lkb and the function will return
+   0.  If the rsb's nodeid is _not_ known, it needs to be looked up
+   before it can be copied to the lkb.
+
+   When the rsb nodeid is being looked up remotely, the initial lkb
+   causing the lookup is kept on the ls_waiters list waiting for the
+   lookup reply.  Other lkb's waiting for the same rsb lookup are kept
+   on the rsb's res_lookup list until the master is verified.
+
+   Return values:
+   0: nodeid is set in rsb/lkb and the caller should go ahead and use it
+   1: the rsb master is not available and the lkb has been placed on
+      a wait queue
+*/
+
+static int set_master(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	struct dlm_ls *ls = r->res_ls;
+	int error, dir_nodeid, ret_nodeid, our_nodeid = dlm_our_nodeid();
+
+	if (rsb_flag(r, RSB_MASTER_UNCERTAIN)) {
+		rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
+		r->res_first_lkid = lkb->lkb_id;
+		lkb->lkb_nodeid = r->res_nodeid;
+		return 0;
+	}
+
+	if (r->res_first_lkid && r->res_first_lkid != lkb->lkb_id) {
+		list_add_tail(&lkb->lkb_rsb_lookup, &r->res_lookup);
+		return 1;
+	}
+
+	if (r->res_nodeid == 0) {
+		lkb->lkb_nodeid = 0;
+		return 0;
+	}
+
+	if (r->res_nodeid > 0) {
+		lkb->lkb_nodeid = r->res_nodeid;
+		return 0;
+	}
+
+	DLM_ASSERT(r->res_nodeid == -1, dlm_print_rsb(r););
+
+	dir_nodeid = dlm_dir_nodeid(r);
+
+	if (dir_nodeid != our_nodeid) {
+		r->res_first_lkid = lkb->lkb_id;
+		send_lookup(r, lkb);
+		return 1;
+	}
+
+	for (;;) {
+		/* It's possible for dlm_scand to remove an old rsb for
+		   this same resource from the toss list, us to create
+		   a new one, look up the master locally, and find it
+		   already exists just before dlm_scand does the
+		   dir_remove() on the previous rsb. */
+
+		error = dlm_dir_lookup(ls, our_nodeid, r->res_name,
+				       r->res_length, &ret_nodeid);
+		if (!error)
+			break;
+		log_debug(ls, "dir_lookup error %d %s", error, r->res_name);
+		schedule();
+	}
+
+	if (ret_nodeid == our_nodeid) {
+		r->res_first_lkid = 0;
+		r->res_nodeid = 0;
+		lkb->lkb_nodeid = 0;
+	} else {
+		r->res_first_lkid = lkb->lkb_id;
+		r->res_nodeid = ret_nodeid;
+		lkb->lkb_nodeid = ret_nodeid;
+	}
+	return 0;
+}
+
+static void process_lookup_list(struct dlm_rsb *r)
+{
+	struct dlm_lkb *lkb, *safe;
+
+	list_for_each_entry_safe(lkb, safe, &r->res_lookup, lkb_rsb_lookup) {
+		list_del(&lkb->lkb_rsb_lookup);
+		_request_lock(r, lkb);
+		schedule();
+	}
+}
+
+/* confirm_master -- confirm (or deny) an rsb's master nodeid */
+
+static void confirm_master(struct dlm_rsb *r, int error)
+{
+	struct dlm_lkb *lkb;
+
+	if (!r->res_first_lkid)
+		return;
+
+	switch (error) {
+	case 0:
+	case -EINPROGRESS:
+		r->res_first_lkid = 0;
+		process_lookup_list(r);
+		break;
+
+	case -EAGAIN:
+		/* the remote master didn't queue our NOQUEUE request;
+		   make a waiting lkb the first_lkid */
+
+		r->res_first_lkid = 0;
+
+		if (!list_empty(&r->res_lookup)) {
+			lkb = list_entry(r->res_lookup.next, struct dlm_lkb,
+					 lkb_rsb_lookup);
+			list_del(&lkb->lkb_rsb_lookup);
+			r->res_first_lkid = lkb->lkb_id;
+			_request_lock(r, lkb);
+		} else
+			r->res_nodeid = -1;
+		break;
+
+	default:
+		log_error(r->res_ls, "confirm_master unknown error %d", error);
+	}
+}
+
+static int set_lock_args(int mode, struct dlm_lksb *lksb, uint32_t flags,
+			 int namelen, uint32_t parent_lkid, void *ast,
+			 void *astarg, void *bast, struct dlm_range *range,
+			 struct dlm_args *args)
+{
+	int rv = -EINVAL;
+
+	/* check for invalid arg usage */
+
+	if (mode < 0 || mode > DLM_LOCK_EX)
+		goto out;
+
+	if (!(flags & DLM_LKF_CONVERT) && (namelen > DLM_RESNAME_MAXLEN))
+		goto out;
+
+	if (flags & DLM_LKF_CANCEL)
+		goto out;
+
+	if (flags & DLM_LKF_QUECVT && !(flags & DLM_LKF_CONVERT))
+		goto out;
+
+	if (flags & DLM_LKF_CONVDEADLK && !(flags & DLM_LKF_CONVERT))
+		goto out;
+
+	if (flags & DLM_LKF_CONVDEADLK && flags & DLM_LKF_NOQUEUE)
+		goto out;
+
+	if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_CONVERT)
+		goto out;
+
+	if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_QUECVT)
+		goto out;
+
+	if (flags & DLM_LKF_EXPEDITE && flags & DLM_LKF_NOQUEUE)
+		goto out;
+
+	if (flags & DLM_LKF_EXPEDITE && mode != DLM_LOCK_NL)
+		goto out;
+
+	if (!ast || !lksb)
+		goto out;
+
+	if (flags & DLM_LKF_VALBLK && !lksb->sb_lvbptr)
+		goto out;
+
+	/* parent/child locks not yet supported */
+	if (parent_lkid)
+		goto out;
+
+	if (flags & DLM_LKF_CONVERT && !lksb->sb_lkid)
+		goto out;
+
+	/* these args will be copied to the lkb in validate_lock_args,
+	   it cannot be done now because when converting locks, fields in
+	   an active lkb cannot be modified before locking the rsb */
+
+	args->flags = flags;
+	args->astaddr = ast;
+	args->astparam = (long) astarg;
+	args->bastaddr = bast;
+	args->mode = mode;
+	args->lksb = lksb;
+	args->range = range;
+	rv = 0;
+ out:
+	return rv;
+}
+
+static int set_unlock_args(uint32_t flags, void *astarg, struct dlm_args *args)
+{
+	if (flags & ~(DLM_LKF_CANCEL | DLM_LKF_VALBLK | DLM_LKF_IVVALBLK |
+ 		      DLM_LKF_FORCEUNLOCK))
+		return -EINVAL;
+
+	args->flags = flags;
+	args->astparam = (long) astarg;
+	return 0;
+}
+
+static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
+			      struct dlm_args *args)
+{
+	int rv = -EINVAL;
+
+	if (args->flags & DLM_LKF_CONVERT) {
+		if (lkb->lkb_flags & DLM_IFL_MSTCPY)
+			goto out;
+
+		if (args->flags & DLM_LKF_QUECVT &&
+		    !__quecvt_compat_matrix[lkb->lkb_grmode+1][args->mode+1])
+			goto out;
+
+		rv = -EBUSY;
+		if (lkb->lkb_status != DLM_LKSTS_GRANTED)
+			goto out;
+
+		if (lkb->lkb_wait_type)
+			goto out;
+	}
+
+	lkb->lkb_exflags = args->flags;
+	lkb->lkb_sbflags = 0;
+	lkb->lkb_astaddr = args->astaddr;
+	lkb->lkb_astparam = args->astparam;
+	lkb->lkb_bastaddr = args->bastaddr;
+	lkb->lkb_rqmode = args->mode;
+	lkb->lkb_lksb = args->lksb;
+	lkb->lkb_lvbptr = args->lksb->sb_lvbptr;
+	lkb->lkb_ownpid = (int) current->pid;
+
+	rv = 0;
+	if (!args->range)
+		goto out;
+
+	if (!lkb->lkb_range) {
+		rv = -ENOMEM;
+		lkb->lkb_range = allocate_range(ls);
+		if (!lkb->lkb_range)
+			goto out;
+		/* This is needed for conversions that contain ranges
+		   where the original lock didn't but it's harmless for
+		   new locks too. */
+		lkb->lkb_range[GR_RANGE_START] = 0LL;
+		lkb->lkb_range[GR_RANGE_END] = 0xffffffffffffffffULL;
+	}
+
+	lkb->lkb_range[RQ_RANGE_START] = args->range->ra_start;
+	lkb->lkb_range[RQ_RANGE_END] = args->range->ra_end;
+	lkb->lkb_flags |= DLM_IFL_RANGE;
+	rv = 0;
+ out:
+	return rv;
+}
+
+static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
+{
+	int rv = -EINVAL;
+
+	if (lkb->lkb_flags & DLM_IFL_MSTCPY)
+		goto out;
+
+	if (args->flags & DLM_LKF_FORCEUNLOCK)
+		goto out_ok;
+
+	if (args->flags & DLM_LKF_CANCEL &&
+	    lkb->lkb_status == DLM_LKSTS_GRANTED)
+		goto out;
+
+	if (!(args->flags & DLM_LKF_CANCEL) &&
+	    lkb->lkb_status != DLM_LKSTS_GRANTED)
+		goto out;
+
+	rv = -EBUSY;
+	if (lkb->lkb_wait_type)
+		goto out;
+
+ out_ok:
+	lkb->lkb_exflags = args->flags;
+	lkb->lkb_sbflags = 0;
+	lkb->lkb_astparam = args->astparam;
+
+	rv = 0;
+ out:
+	return rv;
+}
+
+/*
+ * Four stage 4 varieties:
+ * do_request(), do_convert(), do_unlock(), do_cancel()
+ * These are called on the master node for the given lock and
+ * from the central locking logic.
+ */
+
+static int do_request(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error = 0;
+
+	if (can_be_granted(r, lkb, TRUE)) {
+		grant_lock(r, lkb);
+		queue_cast(r, lkb, 0);
+		goto out;
+	}
+
+	if (can_be_queued(lkb)) {
+		error = -EINPROGRESS;
+		add_lkb(r, lkb, DLM_LKSTS_WAITING);
+		send_blocking_asts(r, lkb);
+		goto out;
+	}
+
+	error = -EAGAIN;
+	if (force_blocking_asts(lkb))
+		send_blocking_asts_all(r, lkb);
+	queue_cast(r, lkb, -EAGAIN);
+
+ out:
+	return error;
+}
+
+static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error = 0;
+
+	/* changing an existing lock may allow others to be granted */
+
+	if (can_be_granted(r, lkb, TRUE)) {
+		grant_lock(r, lkb);
+		queue_cast(r, lkb, 0);
+		grant_pending_locks(r);
+		goto out;
+	}
+
+	if (can_be_queued(lkb)) {
+		if (is_demoted(lkb))
+			grant_pending_locks(r);
+		error = -EINPROGRESS;
+		del_lkb(r, lkb);
+		add_lkb(r, lkb, DLM_LKSTS_CONVERT);
+		send_blocking_asts(r, lkb);
+		goto out;
+	}
+
+	error = -EAGAIN;
+	if (force_blocking_asts(lkb))
+		send_blocking_asts_all(r, lkb);
+	queue_cast(r, lkb, -EAGAIN);
+
+ out:
+	return error;
+}
+
+static int do_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	remove_lock(r, lkb);
+	queue_cast(r, lkb, -DLM_EUNLOCK);
+	grant_pending_locks(r);
+	return -DLM_EUNLOCK;
+}
+
+static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	revert_lock(r, lkb);
+	queue_cast(r, lkb, -DLM_ECANCEL);
+	grant_pending_locks(r);
+	return -DLM_ECANCEL;
+}
+
+/*
+ * Four stage 3 varieties:
+ * _request_lock(), _convert_lock(), _unlock_lock(), _cancel_lock()
+ */
+
+/* add a new lkb to a possibly new rsb, called by requesting process */
+
+static int _request_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error;
+
+	/* set_master: sets lkb nodeid from r */
+
+	error = set_master(r, lkb);
+	if (error < 0)
+		goto out;
+	if (error) {
+		error = 0;
+		goto out;
+	}
+
+	if (is_remote(r))
+		/* receive_request() calls do_request() on remote node */
+		error = send_request(r, lkb);
+	else
+		error = do_request(r, lkb);
+ out:
+	return error;
+}
+
+/* change some property of an existing lkb, e.g. mode, range */
+
+static int _convert_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error;
+
+	if (is_remote(r))
+		/* receive_convert() calls do_convert() on remote node */
+		error = send_convert(r, lkb);
+	else
+		error = do_convert(r, lkb);
+
+	return error;
+}
+
+/* remove an existing lkb from the granted queue */
+
+static int _unlock_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error;
+
+	if (is_remote(r))
+		/* receive_unlock() calls do_unlock() on remote node */
+		error = send_unlock(r, lkb);
+	else
+		error = do_unlock(r, lkb);
+
+	return error;
+}
+
+/* remove an existing lkb from the convert or wait queue */
+
+static int _cancel_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error;
+
+	if (is_remote(r))
+		/* receive_cancel() calls do_cancel() on remote node */
+		error = send_cancel(r, lkb);
+	else
+		error = do_cancel(r, lkb);
+
+	return error;
+}
+
+/*
+ * Four stage 2 varieties:
+ * request_lock(), convert_lock(), unlock_lock(), cancel_lock()
+ */
+
+static int request_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, char *name,
+			int len, struct dlm_args *args)
+{
+	struct dlm_rsb *r;
+	int error;
+
+	error = validate_lock_args(ls, lkb, args);
+	if (error)
+		goto out;
+
+	error = find_rsb(ls, name, len, R_CREATE, &r);
+	if (error)
+		goto out;
+
+	lock_rsb(r);
+
+	attach_lkb(r, lkb);
+	lkb->lkb_lksb->sb_lkid = lkb->lkb_id;
+
+	error = _request_lock(r, lkb);
+
+	unlock_rsb(r);
+	put_rsb(r);
+
+ out:
+	return error;
+}
+
+static int convert_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
+			struct dlm_args *args)
+{
+	struct dlm_rsb *r;
+	int error;
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	error = validate_lock_args(ls, lkb, args);
+	if (error)
+		goto out;
+
+	error = _convert_lock(r, lkb);
+ out:
+	unlock_rsb(r);
+	put_rsb(r);
+	return error;
+}
+
+static int unlock_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
+		       struct dlm_args *args)
+{
+	struct dlm_rsb *r;
+	int error;
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	error = validate_unlock_args(lkb, args);
+	if (error)
+		goto out;
+
+	error = _unlock_lock(r, lkb);
+ out:
+	unlock_rsb(r);
+	put_rsb(r);
+	return error;
+}
+
+static int cancel_lock(struct dlm_ls *ls, struct dlm_lkb *lkb,
+		       struct dlm_args *args)
+{
+	struct dlm_rsb *r;
+	int error;
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	error = validate_unlock_args(lkb, args);
+	if (error)
+		goto out;
+
+	error = _cancel_lock(r, lkb);
+ out:
+	unlock_rsb(r);
+	put_rsb(r);
+	return error;
+}
+
+/*
+ * Two stage 1 varieties:  dlm_lock() and dlm_unlock()
+ */
+
+int dlm_lock(dlm_lockspace_t *lockspace,
+	     int mode,
+	     struct dlm_lksb *lksb,
+	     uint32_t flags,
+	     void *name,
+	     unsigned int namelen,
+	     uint32_t parent_lkid,
+	     void (*ast) (void *astarg),
+	     void *astarg,
+	     void (*bast) (void *astarg, int mode),
+	     struct dlm_range *range)
+{
+	struct dlm_ls *ls;
+	struct dlm_lkb *lkb;
+	struct dlm_args args;
+	int error, convert = flags & DLM_LKF_CONVERT;
+
+	ls = dlm_find_lockspace_local(lockspace);
+	if (!ls)
+		return -EINVAL;
+
+	lock_recovery(ls);
+
+	if (convert)
+		error = find_lkb(ls, lksb->sb_lkid, &lkb);
+	else
+		error = create_lkb(ls, &lkb);
+
+	if (error)
+		goto out;
+
+	error = set_lock_args(mode, lksb, flags, namelen, parent_lkid, ast,
+			      astarg, bast, range, &args);
+	if (error)
+		goto out_put;
+
+	if (convert)
+		error = convert_lock(ls, lkb, &args);
+	else
+		error = request_lock(ls, lkb, name, namelen, &args);
+
+	if (error == -EINPROGRESS)
+		error = 0;
+ out_put:
+	if (convert || error)
+		put_lkb(lkb);
+	if (error == -EAGAIN)
+		error = 0;
+ out:
+	unlock_recovery(ls);
+	dlm_put_lockspace(ls);
+	return error;
+}
+
+int dlm_unlock(dlm_lockspace_t *lockspace,
+	       uint32_t lkid,
+	       uint32_t flags,
+	       struct dlm_lksb *lksb,
+	       void *astarg)
+{
+	struct dlm_ls *ls;
+	struct dlm_lkb *lkb;
+	struct dlm_args args;
+	int error;
+
+	ls = dlm_find_lockspace_local(lockspace);
+	if (!ls)
+		return -EINVAL;
+
+	lock_recovery(ls);
+
+	error = find_lkb(ls, lkid, &lkb);
+	if (error)
+		goto out;
+
+	error = set_unlock_args(flags, astarg, &args);
+	if (error)
+		goto out_put;
+
+	if (flags & DLM_LKF_CANCEL)
+		error = cancel_lock(ls, lkb, &args);
+	else
+		error = unlock_lock(ls, lkb, &args);
+
+	if (error == -DLM_EUNLOCK || error == -DLM_ECANCEL)
+		error = 0;
+ out_put:
+	put_lkb(lkb);
+ out:
+	unlock_recovery(ls);
+	dlm_put_lockspace(ls);
+	return error;
+}
+
+/*
+ * send/receive routines for remote operations and replies
+ *
+ * send_args
+ * send_common
+ * send_request			receive_request
+ * send_convert			receive_convert
+ * send_unlock			receive_unlock
+ * send_cancel			receive_cancel
+ * send_grant			receive_grant
+ * send_bast			receive_bast
+ * send_lookup			receive_lookup
+ * send_remove			receive_remove
+ *
+ * 				send_common_reply
+ * receive_request_reply	send_request_reply
+ * receive_convert_reply	send_convert_reply
+ * receive_unlock_reply		send_unlock_reply
+ * receive_cancel_reply		send_cancel_reply
+ * receive_lookup_reply		send_lookup_reply
+ */
+
+static int create_message(struct dlm_rsb *r, struct dlm_lkb *lkb,
+			  int to_nodeid, int mstype,
+			  struct dlm_message **ms_ret,
+			  struct dlm_mhandle **mh_ret)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	char *mb;
+	int mb_len = sizeof(struct dlm_message);
+
+	switch (mstype) {
+	case DLM_MSG_REQUEST:
+	case DLM_MSG_LOOKUP:
+	case DLM_MSG_REMOVE:
+		mb_len += r->res_length;
+		break;
+	case DLM_MSG_CONVERT:
+	case DLM_MSG_UNLOCK:
+	case DLM_MSG_REQUEST_REPLY:
+	case DLM_MSG_CONVERT_REPLY:
+	case DLM_MSG_GRANT:
+		if (lkb && lkb->lkb_lvbptr)
+			mb_len += r->res_ls->ls_lvblen;
+		break;
+	}
+
+	/* get_buffer gives us a message handle (mh) that we need to
+	   pass into lowcomms_commit and a message buffer (mb) that we
+	   write our data into */
+
+	mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_KERNEL, &mb);
+	if (!mh)
+		return -ENOBUFS;
+
+	memset(mb, 0, mb_len);
+
+	ms = (struct dlm_message *) mb;
+
+	ms->m_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+	ms->m_header.h_lockspace = r->res_ls->ls_global_id;
+	ms->m_header.h_nodeid = dlm_our_nodeid();
+	ms->m_header.h_length = mb_len;
+	ms->m_header.h_cmd = DLM_MSG;
+
+	ms->m_type = mstype;
+
+	*mh_ret = mh;
+	*ms_ret = ms;
+	return 0;
+}
+
+/* further lowcomms enhancements or alternate implementations may make
+   the return value from this function useful at some point */
+
+static int send_message(struct dlm_mhandle *mh, struct dlm_message *ms)
+{
+	dlm_message_out(ms);
+	dlm_lowcomms_commit_buffer(mh);
+	return 0;
+}
+
+static void send_args(struct dlm_rsb *r, struct dlm_lkb *lkb,
+		      struct dlm_message *ms)
+{
+	ms->m_nodeid   = lkb->lkb_nodeid;
+	ms->m_pid      = lkb->lkb_ownpid;
+	ms->m_lkid     = lkb->lkb_id;
+	ms->m_remid    = lkb->lkb_remid;
+	ms->m_exflags  = lkb->lkb_exflags;
+	ms->m_sbflags  = lkb->lkb_sbflags;
+	ms->m_flags    = lkb->lkb_flags;
+	ms->m_lvbseq   = lkb->lkb_lvbseq;
+	ms->m_status   = lkb->lkb_status;
+	ms->m_grmode   = lkb->lkb_grmode;
+	ms->m_rqmode   = lkb->lkb_rqmode;
+	ms->m_hash     = r->res_hash;
+
+	/* m_result and m_bastmode are set from function args,
+	   not from lkb fields */
+
+	if (lkb->lkb_bastaddr)
+		ms->m_asts |= AST_BAST;
+	if (lkb->lkb_astaddr)
+		ms->m_asts |= AST_COMP;
+
+	if (lkb->lkb_range) {
+		ms->m_range[0] = lkb->lkb_range[RQ_RANGE_START];
+		ms->m_range[1] = lkb->lkb_range[RQ_RANGE_END];
+	}
+
+	if (ms->m_type == DLM_MSG_REQUEST || ms->m_type == DLM_MSG_LOOKUP)
+		memcpy(ms->m_extra, r->res_name, r->res_length);
+
+	else if (lkb->lkb_lvbptr)
+		memcpy(ms->m_extra, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
+
+}
+
+static int send_common(struct dlm_rsb *r, struct dlm_lkb *lkb, int mstype)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int to_nodeid, error;
+
+	add_to_waiters(lkb, mstype);
+
+	to_nodeid = r->res_nodeid;
+
+	error = create_message(r, lkb, to_nodeid, mstype, &ms, &mh);
+	if (error)
+		goto fail;
+
+	send_args(r, lkb, ms);
+
+	error = send_message(mh, ms);
+	if (error)
+		goto fail;
+	return 0;
+
+ fail:
+	remove_from_waiters(lkb);
+	return error;
+}
+
+static int send_request(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	return send_common(r, lkb, DLM_MSG_REQUEST);
+}
+
+static int send_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	int error;
+
+	error = send_common(r, lkb, DLM_MSG_CONVERT);
+
+	/* down conversions go without a reply from the master */
+	if (!error && down_conversion(lkb)) {
+		remove_from_waiters(lkb);
+		r->res_ls->ls_stub_ms.m_result = 0;
+		__receive_convert_reply(r, lkb, &r->res_ls->ls_stub_ms);
+	}
+
+	return error;
+}
+
+/* FIXME: if this lkb is the only lock we hold on the rsb, then set
+   MASTER_UNCERTAIN to force the next request on the rsb to confirm
+   that the master is still correct. */
+
+static int send_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	return send_common(r, lkb, DLM_MSG_UNLOCK);
+}
+
+static int send_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	return send_common(r, lkb, DLM_MSG_CANCEL);
+}
+
+static int send_grant(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int to_nodeid, error;
+
+	to_nodeid = lkb->lkb_nodeid;
+
+	error = create_message(r, lkb, to_nodeid, DLM_MSG_GRANT, &ms, &mh);
+	if (error)
+		goto out;
+
+	send_args(r, lkb, ms);
+
+	ms->m_result = 0;
+
+	error = send_message(mh, ms);
+ out:
+	return error;
+}
+
+static int send_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int mode)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int to_nodeid, error;
+
+	to_nodeid = lkb->lkb_nodeid;
+
+	error = create_message(r, NULL, to_nodeid, DLM_MSG_BAST, &ms, &mh);
+	if (error)
+		goto out;
+
+	send_args(r, lkb, ms);
+
+	ms->m_bastmode = mode;
+
+	error = send_message(mh, ms);
+ out:
+	return error;
+}
+
+static int send_lookup(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int to_nodeid, error;
+
+	add_to_waiters(lkb, DLM_MSG_LOOKUP);
+
+	to_nodeid = dlm_dir_nodeid(r);
+
+	error = create_message(r, NULL, to_nodeid, DLM_MSG_LOOKUP, &ms, &mh);
+	if (error)
+		goto fail;
+
+	send_args(r, lkb, ms);
+
+	error = send_message(mh, ms);
+	if (error)
+		goto fail;
+	return 0;
+
+ fail:
+	remove_from_waiters(lkb);
+	return error;
+}
+
+static int send_remove(struct dlm_rsb *r)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int to_nodeid, error;
+
+	to_nodeid = dlm_dir_nodeid(r);
+
+	error = create_message(r, NULL, to_nodeid, DLM_MSG_REMOVE, &ms, &mh);
+	if (error)
+		goto out;
+
+	memcpy(ms->m_extra, r->res_name, r->res_length);
+	ms->m_hash = r->res_hash;
+
+	error = send_message(mh, ms);
+ out:
+	return error;
+}
+
+static int send_common_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
+			     int mstype, int rv)
+{
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int to_nodeid, error;
+
+	to_nodeid = lkb->lkb_nodeid;
+
+	error = create_message(r, lkb, to_nodeid, mstype, &ms, &mh);
+	if (error)
+		goto out;
+
+	send_args(r, lkb, ms);
+
+	ms->m_result = rv;
+
+	error = send_message(mh, ms);
+ out:
+	return error;
+}
+
+static int send_request_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
+{
+	return send_common_reply(r, lkb, DLM_MSG_REQUEST_REPLY, rv);
+}
+
+static int send_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
+{
+	return send_common_reply(r, lkb, DLM_MSG_CONVERT_REPLY, rv);
+}
+
+static int send_unlock_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
+{
+	return send_common_reply(r, lkb, DLM_MSG_UNLOCK_REPLY, rv);
+}
+
+static int send_cancel_reply(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
+{
+	return send_common_reply(r, lkb, DLM_MSG_CANCEL_REPLY, rv);
+}
+
+static int send_lookup_reply(struct dlm_ls *ls, struct dlm_message *ms_in,
+			     int ret_nodeid, int rv)
+{
+	struct dlm_rsb *r = &ls->ls_stub_rsb;
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	int error, nodeid = ms_in->m_header.h_nodeid;
+
+	error = create_message(r, NULL, nodeid, DLM_MSG_LOOKUP_REPLY, &ms, &mh);
+	if (error)
+		goto out;
+
+	ms->m_lkid = ms_in->m_lkid;
+	ms->m_result = rv;
+	ms->m_nodeid = ret_nodeid;
+
+	error = send_message(mh, ms);
+ out:
+	return error;
+}
+
+/* which args we save from a received message depends heavily on the type
+   of message, unlike the send side where we can safely send everything about
+   the lkb for any type of message */
+
+static void receive_flags(struct dlm_lkb *lkb, struct dlm_message *ms)
+{
+	lkb->lkb_exflags = ms->m_exflags;
+	lkb->lkb_flags = (lkb->lkb_flags & 0xFFFF0000) |
+		         (ms->m_flags & 0x0000FFFF);
+}
+
+static void receive_flags_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
+{
+	lkb->lkb_sbflags = ms->m_sbflags;
+	lkb->lkb_flags = (lkb->lkb_flags & 0xFFFF0000) |
+		         (ms->m_flags & 0x0000FFFF);
+}
+
+static int receive_extralen(struct dlm_message *ms)
+{
+	return (ms->m_header.h_length - sizeof(struct dlm_message));
+}
+
+static int receive_range(struct dlm_ls *ls, struct dlm_lkb *lkb,
+			 struct dlm_message *ms)
+{
+	if (lkb->lkb_flags & DLM_IFL_RANGE) {
+		if (!lkb->lkb_range)
+			lkb->lkb_range = allocate_range(ls);
+		if (!lkb->lkb_range)
+			return -ENOMEM;
+		lkb->lkb_range[RQ_RANGE_START] = ms->m_range[0];
+		lkb->lkb_range[RQ_RANGE_END] = ms->m_range[1];
+	}
+	return 0;
+}
+
+static int receive_lvb(struct dlm_ls *ls, struct dlm_lkb *lkb,
+		       struct dlm_message *ms)
+{
+	int len;
+
+	if (lkb->lkb_exflags & DLM_LKF_VALBLK) {
+		if (!lkb->lkb_lvbptr)
+			lkb->lkb_lvbptr = allocate_lvb(ls);
+		if (!lkb->lkb_lvbptr)
+			return -ENOMEM;
+		len = receive_extralen(ms);
+		memcpy(lkb->lkb_lvbptr, ms->m_extra, len);
+	}
+	return 0;
+}
+
+static int receive_request_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
+				struct dlm_message *ms)
+{
+	lkb->lkb_nodeid = ms->m_header.h_nodeid;
+	lkb->lkb_ownpid = ms->m_pid;
+	lkb->lkb_remid = ms->m_lkid;
+	lkb->lkb_grmode = DLM_LOCK_IV;
+	lkb->lkb_rqmode = ms->m_rqmode;
+	lkb->lkb_bastaddr = (void *) (long) (ms->m_asts & AST_BAST);
+	lkb->lkb_astaddr = (void *) (long) (ms->m_asts & AST_COMP);
+
+	DLM_ASSERT(is_master_copy(lkb), dlm_print_lkb(lkb););
+
+	if (receive_range(ls, lkb, ms))
+		return -ENOMEM;
+
+	if (receive_lvb(ls, lkb, ms))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int receive_convert_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
+				struct dlm_message *ms)
+{
+	if (lkb->lkb_nodeid != ms->m_header.h_nodeid) {
+		log_error(ls, "convert_args nodeid %d %d lkid %x %x",
+			  lkb->lkb_nodeid, ms->m_header.h_nodeid,
+			  lkb->lkb_id, lkb->lkb_remid);
+		return -EINVAL;
+	}
+
+	if (!is_master_copy(lkb))
+		return -EINVAL;
+
+	if (lkb->lkb_status != DLM_LKSTS_GRANTED)
+		return -EBUSY;
+
+	if (receive_range(ls, lkb, ms))
+		return -ENOMEM;
+	if (lkb->lkb_range) {
+		lkb->lkb_range[GR_RANGE_START] = 0LL;
+		lkb->lkb_range[GR_RANGE_END] = 0xffffffffffffffffULL;
+	}
+
+	if (receive_lvb(ls, lkb, ms))
+		return -ENOMEM;
+
+	lkb->lkb_rqmode = ms->m_rqmode;
+	lkb->lkb_lvbseq = ms->m_lvbseq;
+
+	return 0;
+}
+
+static int receive_unlock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
+			       struct dlm_message *ms)
+{
+	if (!is_master_copy(lkb))
+		return -EINVAL;
+	if (receive_lvb(ls, lkb, ms))
+		return -ENOMEM;
+	return 0;
+}
+
+/* We fill in the stub-lkb fields with the info that send_xxxx_reply()
+   uses to send a reply and that the remote end uses to process the reply. */
+
+static void setup_stub_lkb(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb = &ls->ls_stub_lkb;
+	lkb->lkb_nodeid = ms->m_header.h_nodeid;
+	lkb->lkb_remid = ms->m_lkid;
+}
+
+static void receive_request(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error, namelen;
+
+	error = create_lkb(ls, &lkb);
+	if (error)
+		goto fail;
+
+	receive_flags(lkb, ms);
+	lkb->lkb_flags |= DLM_IFL_MSTCPY;
+	error = receive_request_args(ls, lkb, ms);
+	if (error) {
+		put_lkb(lkb);
+		goto fail;
+	}
+
+	namelen = receive_extralen(ms);
+
+	error = find_rsb(ls, ms->m_extra, namelen, R_MASTER, &r);
+	if (error) {
+		put_lkb(lkb);
+		goto fail;
+	}
+
+	lock_rsb(r);
+
+	attach_lkb(r, lkb);
+	error = do_request(r, lkb);
+	send_request_reply(r, lkb, error);
+
+	unlock_rsb(r);
+	put_rsb(r);
+
+	if (error == -EINPROGRESS)
+		error = 0;
+	if (error)
+		put_lkb(lkb);
+	return;
+
+ fail:
+	setup_stub_lkb(ls, ms);
+	send_request_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
+}
+
+static void receive_convert(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error, reply = TRUE;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error)
+		goto fail;
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	receive_flags(lkb, ms);
+	error = receive_convert_args(ls, lkb, ms);
+	if (error)
+		goto out;
+	reply = !down_conversion(lkb);
+
+	error = do_convert(r, lkb);
+ out:
+	if (reply)
+		send_convert_reply(r, lkb, error);
+
+	unlock_rsb(r);
+	put_rsb(r);
+	put_lkb(lkb);
+	return;
+
+ fail:
+	setup_stub_lkb(ls, ms);
+	send_convert_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
+}
+
+static void receive_unlock(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error)
+		goto fail;
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	receive_flags(lkb, ms);
+	error = receive_unlock_args(ls, lkb, ms);
+	if (error)
+		goto out;
+
+	error = do_unlock(r, lkb);
+ out:
+	send_unlock_reply(r, lkb, error);
+
+	unlock_rsb(r);
+	put_rsb(r);
+	put_lkb(lkb);
+	return;
+
+ fail:
+	setup_stub_lkb(ls, ms);
+	send_unlock_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
+}
+
+static void receive_cancel(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error)
+		goto fail;
+
+	receive_flags(lkb, ms);
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	error = do_cancel(r, lkb);
+	send_cancel_reply(r, lkb, error);
+
+	unlock_rsb(r);
+	put_rsb(r);
+	put_lkb(lkb);
+	return;
+
+ fail:
+	setup_stub_lkb(ls, ms);
+	send_cancel_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
+}
+
+static void receive_grant(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error) {
+		log_error(ls, "receive_grant no lkb");
+		return;
+	}
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	receive_flags_reply(lkb, ms);
+	grant_lock_pc(r, lkb, ms);
+	queue_cast(r, lkb, 0);
+
+	unlock_rsb(r);
+	put_rsb(r);
+	put_lkb(lkb);
+}
+
+static void receive_bast(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error) {
+		log_error(ls, "receive_bast no lkb");
+		return;
+	}
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	queue_bast(r, lkb, ms->m_bastmode);
+
+	unlock_rsb(r);
+	put_rsb(r);
+	put_lkb(lkb);
+}
+
+static void receive_lookup(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	int len, error, ret_nodeid, dir_nodeid, from_nodeid, our_nodeid;
+
+	from_nodeid = ms->m_header.h_nodeid;
+	our_nodeid = dlm_our_nodeid();
+
+	len = receive_extralen(ms);
+
+	dir_nodeid = dlm_hash2nodeid(ls, ms->m_hash);
+	if (dir_nodeid != our_nodeid) {
+		log_error(ls, "lookup dir_nodeid %d from %d",
+			  dir_nodeid, from_nodeid);
+		error = -EINVAL;
+		ret_nodeid = -1;
+		goto out;
+	}
+
+	error = dlm_dir_lookup(ls, from_nodeid, ms->m_extra, len, &ret_nodeid);
+
+	/* Optimization: we're master so treat lookup as a request */
+	if (!error && ret_nodeid == our_nodeid) {
+		receive_request(ls, ms);
+		return;
+	}
+ out:
+	send_lookup_reply(ls, ms, ret_nodeid, error);
+}
+
+static void receive_remove(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	int len, dir_nodeid, from_nodeid;
+
+	from_nodeid = ms->m_header.h_nodeid;
+
+	len = receive_extralen(ms);
+
+	dir_nodeid = dlm_hash2nodeid(ls, ms->m_hash);
+	if (dir_nodeid != dlm_our_nodeid()) {
+		log_error(ls, "remove dir entry dir_nodeid %d from %d",
+			  dir_nodeid, from_nodeid);
+		return;
+	}
+
+	dlm_dir_remove_entry(ls, from_nodeid, ms->m_extra, len);
+}
+
+static void receive_request_reply(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error, mstype;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error) {
+		log_error(ls, "receive_request_reply no lkb");
+		return;
+	}
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	mstype = lkb->lkb_wait_type;
+	error = remove_from_waiters(lkb);
+	if (error) {
+		log_error(ls, "receive_request_reply not on waiters");
+		goto out;
+	}
+
+	/* this is the value returned from do_request() on the master */
+	error = ms->m_result;
+
+	r = lkb->lkb_resource;
+	hold_rsb(r);
+	lock_rsb(r);
+
+	/* Optimization: the dir node was also the master, so it took our
+	   lookup as a request and sent request reply instead of lookup reply */
+	if (mstype == DLM_MSG_LOOKUP) {
+		r->res_nodeid = ms->m_header.h_nodeid;
+		lkb->lkb_nodeid = r->res_nodeid;
+	}
+
+	switch (error) {
+	case -EAGAIN:
+		/* request would block (be queued) on remote master;
+		   the unhold undoes the original ref from create_lkb()
+		   so it leads to the lkb being freed */
+		queue_cast(r, lkb, -EAGAIN);
+		confirm_master(r, -EAGAIN);
+		unhold_lkb(lkb);
+		break;
+
+	case -EINPROGRESS:
+	case 0:
+		/* request was queued or granted on remote master */
+		receive_flags_reply(lkb, ms);
+		lkb->lkb_remid = ms->m_lkid;
+		if (error)
+			add_lkb(r, lkb, DLM_LKSTS_WAITING);
+		else {
+			grant_lock_pc(r, lkb, ms);
+			queue_cast(r, lkb, 0);
+		}
+		confirm_master(r, error);
+		break;
+
+	case -ENOENT:
+	case -ENOTBLK:
+		/* find_rsb failed to find rsb or rsb wasn't master */
+		r->res_nodeid = -1;
+		lkb->lkb_nodeid = -1;
+		_request_lock(r, lkb);
+		break;
+
+	default:
+		log_error(ls, "receive_request_reply error %d", error);
+	}
+
+	unlock_rsb(r);
+	put_rsb(r);
+ out:
+	put_lkb(lkb);
+}
+
+static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
+				    struct dlm_message *ms)
+{
+	int error = ms->m_result;
+
+	/* this is the value returned from do_convert() on the master */
+
+	switch (error) {
+	case -EAGAIN:
+		/* convert would block (be queued) on remote master */
+		queue_cast(r, lkb, -EAGAIN);
+		break;
+
+	case -EINPROGRESS:
+		/* convert was queued on remote master */
+		del_lkb(r, lkb);
+		add_lkb(r, lkb, DLM_LKSTS_CONVERT);
+		break;
+
+	case 0:
+		/* convert was granted on remote master */
+		receive_flags_reply(lkb, ms);
+		grant_lock_pc(r, lkb, ms);
+		queue_cast(r, lkb, 0);
+		break;
+
+	default:
+		log_error(r->res_ls, "receive_convert_reply error %d", error);
+	}
+}
+
+static void _receive_convert_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
+{
+	struct dlm_rsb *r = lkb->lkb_resource;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	__receive_convert_reply(r, lkb, ms);
+
+	unlock_rsb(r);
+	put_rsb(r);
+}
+
+static void receive_convert_reply(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error) {
+		log_error(ls, "receive_convert_reply no lkb");
+		return;
+	}
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	error = remove_from_waiters(lkb);
+	if (error) {
+		log_error(ls, "receive_convert_reply not on waiters");
+		goto out;
+	}
+
+	_receive_convert_reply(lkb, ms);
+ out:
+	put_lkb(lkb);
+}
+
+static void _receive_unlock_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
+{
+	struct dlm_rsb *r = lkb->lkb_resource;
+	int error = ms->m_result;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	/* this is the value returned from do_unlock() on the master */
+
+	switch (error) {
+	case -DLM_EUNLOCK:
+		receive_flags_reply(lkb, ms);
+		remove_lock_pc(r, lkb);
+		queue_cast(r, lkb, -DLM_EUNLOCK);
+		break;
+	default:
+		log_error(r->res_ls, "receive_unlock_reply error %d", error);
+	}
+
+	unlock_rsb(r);
+	put_rsb(r);
+}
+
+static void receive_unlock_reply(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error) {
+		log_error(ls, "receive_unlock_reply no lkb");
+		return;
+	}
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	error = remove_from_waiters(lkb);
+	if (error) {
+		log_error(ls, "receive_unlock_reply not on waiters");
+		goto out;
+	}
+
+	_receive_unlock_reply(lkb, ms);
+ out:
+	put_lkb(lkb);
+}
+
+static void _receive_cancel_reply(struct dlm_lkb *lkb, struct dlm_message *ms)
+{
+	struct dlm_rsb *r = lkb->lkb_resource;
+	int error = ms->m_result;
+
+	hold_rsb(r);
+	lock_rsb(r);
+
+	/* this is the value returned from do_cancel() on the master */
+
+	switch (error) {
+	case -DLM_ECANCEL:
+		receive_flags_reply(lkb, ms);
+		revert_lock_pc(r, lkb);
+		queue_cast(r, lkb, -DLM_ECANCEL);
+		break;
+	default:
+		log_error(r->res_ls, "receive_cancel_reply error %d", error);
+	}
+
+	unlock_rsb(r);
+	put_rsb(r);
+}
+
+static void receive_cancel_reply(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	int error;
+
+	error = find_lkb(ls, ms->m_remid, &lkb);
+	if (error) {
+		log_error(ls, "receive_cancel_reply no lkb");
+		return;
+	}
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	error = remove_from_waiters(lkb);
+	if (error) {
+		log_error(ls, "receive_cancel_reply not on waiters");
+		goto out;
+	}
+
+	_receive_cancel_reply(lkb, ms);
+ out:
+	put_lkb(lkb);
+}
+
+static void receive_lookup_reply(struct dlm_ls *ls, struct dlm_message *ms)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error, ret_nodeid;
+
+	error = find_lkb(ls, ms->m_lkid, &lkb);
+	if (error) {
+		log_error(ls, "receive_lookup_reply no lkb");
+		return;
+	}
+
+	error = remove_from_waiters(lkb);
+	if (error) {
+		log_error(ls, "receive_lookup_reply not on waiters");
+		goto out;
+	}
+
+	/* this is the value returned by dlm_dir_lookup on dir node
+	   FIXME: will a non-zero error ever be returned? */
+	error = ms->m_result;
+
+	r = lkb->lkb_resource;
+	hold_rsb(r);
+	lock_rsb(r);
+
+	ret_nodeid = ms->m_nodeid;
+	if (ret_nodeid == dlm_our_nodeid()) {
+		r->res_nodeid = 0;
+		ret_nodeid = 0;
+		r->res_first_lkid = 0;
+	} else {
+		/* set_master() will copy res_nodeid to lkb_nodeid */
+		r->res_nodeid = ret_nodeid;
+	}
+
+	_request_lock(r, lkb);
+
+	if (!ret_nodeid)
+		process_lookup_list(r);
+
+	unlock_rsb(r);
+	put_rsb(r);
+ out:
+	put_lkb(lkb);
+}
+
+int dlm_receive_message(struct dlm_header *hd, int nodeid, int recovery)
+{
+	struct dlm_message *ms = (struct dlm_message *) hd;
+	struct dlm_ls *ls;
+	int error;
+
+	if (!recovery)
+		dlm_message_in(ms);
+
+	ls = dlm_find_lockspace_global(hd->h_lockspace);
+	if (!ls) {
+		log_print("drop message %d from %d for unknown lockspace %d",
+			  ms->m_type, nodeid, hd->h_lockspace);
+		return -EINVAL;
+	}
+
+	/* recovery may have just ended leaving a bunch of backed-up requests
+	   in the requestqueue; wait while dlm_recoverd clears them */
+
+	if (!recovery)
+		dlm_wait_requestqueue(ls);
+
+	/* recovery may have just started while there were a bunch of
+	   in-flight requests -- save them in requestqueue to be processed
+	   after recovery.  we can't let dlm_recvd block on the recovery
+	   lock.  if dlm_recoverd is calling this function to clear the
+	   requestqueue, it needs to be interrupted (-EINTR) if another
+	   recovery operation is starting. */
+
+	while (1) {
+		if (dlm_locking_stopped(ls)) {
+			if (!recovery)
+				dlm_add_requestqueue(ls, nodeid, hd);
+			error = -EINTR;
+			goto out;
+		}
+
+		if (lock_recovery_try(ls))
+			break;
+		schedule();
+	}
+
+	switch (ms->m_type) {
+
+	/* messages sent to a master node */
+
+	case DLM_MSG_REQUEST:
+		receive_request(ls, ms);
+		break;
+
+	case DLM_MSG_CONVERT:
+		receive_convert(ls, ms);
+		break;
+
+	case DLM_MSG_UNLOCK:
+		receive_unlock(ls, ms);
+		break;
+
+	case DLM_MSG_CANCEL:
+		receive_cancel(ls, ms);
+		break;
+
+	/* messages sent from a master node (replies to above) */
+
+	case DLM_MSG_REQUEST_REPLY:
+		receive_request_reply(ls, ms);
+		break;
+
+	case DLM_MSG_CONVERT_REPLY:
+		receive_convert_reply(ls, ms);
+		break;
+
+	case DLM_MSG_UNLOCK_REPLY:
+		receive_unlock_reply(ls, ms);
+		break;
+
+	case DLM_MSG_CANCEL_REPLY:
+		receive_cancel_reply(ls, ms);
+		break;
+
+	/* messages sent from a master node (only two types of async msg) */
+
+	case DLM_MSG_GRANT:
+		receive_grant(ls, ms);
+		break;
+
+	case DLM_MSG_BAST:
+		receive_bast(ls, ms);
+		break;
+
+	/* messages sent to a dir node */
+
+	case DLM_MSG_LOOKUP:
+		receive_lookup(ls, ms);
+		break;
+
+	case DLM_MSG_REMOVE:
+		receive_remove(ls, ms);
+		break;
+
+	/* messages sent from a dir node (remove has no reply) */
+
+	case DLM_MSG_LOOKUP_REPLY:
+		receive_lookup_reply(ls, ms);
+		break;
+
+	default:
+		log_error(ls, "unknown message type %d", ms->m_type);
+	}
+
+	unlock_recovery(ls);
+ out:
+	dlm_put_lockspace(ls);
+	dlm_astd_wake();
+	return 0;
+}
+
+
+/*
+ * Recovery related
+ */
+
+static void recover_convert_waiter(struct dlm_ls *ls, struct dlm_lkb *lkb)
+{
+	if (middle_conversion(lkb)) {
+		hold_lkb(lkb);
+		ls->ls_stub_ms.m_result = -EINPROGRESS;
+		_remove_from_waiters(lkb);
+		_receive_convert_reply(lkb, &ls->ls_stub_ms);
+
+		/* Same special case as in receive_rcom_lock_args() */
+		lkb->lkb_grmode = DLM_LOCK_IV;
+		rsb_set_flag(lkb->lkb_resource, RSB_RECOVER_CONVERT);
+		unhold_lkb(lkb);
+
+	} else if (lkb->lkb_rqmode >= lkb->lkb_grmode) {
+		lkb->lkb_flags |= DLM_IFL_RESEND;
+	}
+
+	/* lkb->lkb_rqmode < lkb->lkb_grmode shouldn't happen since down
+	   conversions are async; there's no reply from the remote master */
+}
+
+/* A waiting lkb needs recovery if the master node has failed, or
+   the master node is changing (only when no directory is used) */
+
+static int waiter_needs_recovery(struct dlm_ls *ls, struct dlm_lkb *lkb)
+{
+	if (dlm_is_removed(ls, lkb->lkb_nodeid))
+		return 1;
+
+	if (!dlm_no_directory(ls))
+		return 0;
+
+	if (dlm_dir_nodeid(lkb->lkb_resource) != lkb->lkb_nodeid)
+		return 1;
+
+	return 0;
+}
+
+/* Recovery for locks that are waiting for replies from nodes that are now
+   gone.  We can just complete unlocks and cancels by faking a reply from the
+   dead node.  Requests and up-conversions we flag to be resent after
+   recovery.  Down-conversions can just be completed with a fake reply like
+   unlocks.  Conversions between PR and CW need special attention. */
+
+void dlm_recover_waiters_pre(struct dlm_ls *ls)
+{
+	struct dlm_lkb *lkb, *safe;
+
+	down(&ls->ls_waiters_sem);
+
+	list_for_each_entry_safe(lkb, safe, &ls->ls_waiters, lkb_wait_reply) {
+		log_debug(ls, "pre recover waiter lkid %x type %d flags %x",
+			  lkb->lkb_id, lkb->lkb_wait_type, lkb->lkb_flags);
+
+		/* all outstanding lookups, regardless of destination  will be
+		   resent after recovery is done */
+
+		if (lkb->lkb_wait_type == DLM_MSG_LOOKUP) {
+			lkb->lkb_flags |= DLM_IFL_RESEND;
+			continue;
+		}
+
+		if (!waiter_needs_recovery(ls, lkb))
+			continue;
+
+		switch (lkb->lkb_wait_type) {
+
+		case DLM_MSG_REQUEST:
+			lkb->lkb_flags |= DLM_IFL_RESEND;
+			break;
+
+		case DLM_MSG_CONVERT:
+			recover_convert_waiter(ls, lkb);
+			break;
+
+		case DLM_MSG_UNLOCK:
+			hold_lkb(lkb);
+			ls->ls_stub_ms.m_result = -DLM_EUNLOCK;
+			_remove_from_waiters(lkb);
+			_receive_unlock_reply(lkb, &ls->ls_stub_ms);
+			put_lkb(lkb);
+			break;
+
+		case DLM_MSG_CANCEL:
+			hold_lkb(lkb);
+			ls->ls_stub_ms.m_result = -DLM_ECANCEL;
+			_remove_from_waiters(lkb);
+			_receive_cancel_reply(lkb, &ls->ls_stub_ms);
+			put_lkb(lkb);
+			break;
+
+		default:
+			log_error(ls, "invalid lkb wait_type %d",
+				  lkb->lkb_wait_type);
+		}
+	}
+	up(&ls->ls_waiters_sem);
+}
+
+static int remove_resend_waiter(struct dlm_ls *ls, struct dlm_lkb **lkb_ret)
+{
+	struct dlm_lkb *lkb;
+	int rv = 0;
+
+	down(&ls->ls_waiters_sem);
+	list_for_each_entry(lkb, &ls->ls_waiters, lkb_wait_reply) {
+		if (lkb->lkb_flags & DLM_IFL_RESEND) {
+			rv = lkb->lkb_wait_type;
+			_remove_from_waiters(lkb);
+			lkb->lkb_flags &= ~DLM_IFL_RESEND;
+			break;
+		}
+	}
+	up(&ls->ls_waiters_sem);
+
+	if (!rv)
+		lkb = NULL;
+	*lkb_ret = lkb;
+	return rv;
+}
+
+/* Deal with lookups and lkb's marked RESEND from _pre.  We may now be the
+   master or dir-node for r.  Processing the lkb may result in it being placed
+   back on waiters. */
+
+int dlm_recover_waiters_post(struct dlm_ls *ls)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *r;
+	int error = 0, mstype;
+
+	while (1) {
+		if (dlm_locking_stopped(ls)) {
+			log_debug(ls, "recover_waiters_post aborted");
+			error = -EINTR;
+			break;
+		}
+
+		mstype = remove_resend_waiter(ls, &lkb);
+		if (!mstype)
+			break;
+
+		r = lkb->lkb_resource;
+
+		log_debug(ls, "recover_waiters_post %x type %d flags %x %s",
+			  lkb->lkb_id, mstype, lkb->lkb_flags, r->res_name);
+
+		switch (mstype) {
+
+		case DLM_MSG_LOOKUP:
+			hold_rsb(r);
+			lock_rsb(r);
+			_request_lock(r, lkb);
+			if (is_master(r))
+				confirm_master(r, 0);
+			unlock_rsb(r);
+			put_rsb(r);
+			break;
+
+		case DLM_MSG_REQUEST:
+			hold_rsb(r);
+			lock_rsb(r);
+			_request_lock(r, lkb);
+			unlock_rsb(r);
+			put_rsb(r);
+			break;
+
+		case DLM_MSG_CONVERT:
+			hold_rsb(r);
+			lock_rsb(r);
+			_convert_lock(r, lkb);
+			unlock_rsb(r);
+			put_rsb(r);
+			break;
+
+		default:
+			log_error(ls, "recover_waiters_post type %d", mstype);
+		}
+	}
+
+	return error;
+}
+
+static void purge_queue(struct dlm_rsb *r, struct list_head *queue,
+			int (*test)(struct dlm_ls *ls, struct dlm_lkb *lkb))
+{
+	struct dlm_ls *ls = r->res_ls;
+	struct dlm_lkb *lkb, *safe;
+
+	list_for_each_entry_safe(lkb, safe, queue, lkb_statequeue) {
+		if (test(ls, lkb)) {
+			del_lkb(r, lkb);
+			/* this put should free the lkb */
+			if (!put_lkb(lkb))
+				log_error(ls, "purged lkb not released");
+		}
+	}
+}
+
+static int purge_dead_test(struct dlm_ls *ls, struct dlm_lkb *lkb)
+{
+	return (is_master_copy(lkb) && dlm_is_removed(ls, lkb->lkb_nodeid));
+}
+
+static int purge_mstcpy_test(struct dlm_ls *ls, struct dlm_lkb *lkb)
+{
+	return is_master_copy(lkb);
+}
+
+static void purge_dead_locks(struct dlm_rsb *r)
+{
+	purge_queue(r, &r->res_grantqueue, &purge_dead_test);
+	purge_queue(r, &r->res_convertqueue, &purge_dead_test);
+	purge_queue(r, &r->res_waitqueue, &purge_dead_test);
+}
+
+void dlm_purge_mstcpy_locks(struct dlm_rsb *r)
+{
+	purge_queue(r, &r->res_grantqueue, &purge_mstcpy_test);
+	purge_queue(r, &r->res_convertqueue, &purge_mstcpy_test);
+	purge_queue(r, &r->res_waitqueue, &purge_mstcpy_test);
+}
+
+/* Get rid of locks held by nodes that are gone. */
+
+int dlm_purge_locks(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r;
+
+	log_debug(ls, "dlm_purge_locks");
+
+	down_write(&ls->ls_root_sem);
+	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
+		hold_rsb(r);
+		lock_rsb(r);
+		if (is_master(r))
+			purge_dead_locks(r);
+		unlock_rsb(r);
+		unhold_rsb(r);
+
+		schedule();
+	}
+	up_write(&ls->ls_root_sem);
+
+	return 0;
+}
+
+int dlm_grant_after_purge(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r;
+	int i;
+
+	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
+		read_lock(&ls->ls_rsbtbl[i].lock);
+		list_for_each_entry(r, &ls->ls_rsbtbl[i].list, res_hashchain) {
+			hold_rsb(r);
+			lock_rsb(r);
+			if (is_master(r)) {
+				grant_pending_locks(r);
+				confirm_master(r, 0);
+			}
+			unlock_rsb(r);
+			put_rsb(r);
+		}
+		read_unlock(&ls->ls_rsbtbl[i].lock);
+	}
+
+	return 0;
+}
+
+static struct dlm_lkb *search_remid_list(struct list_head *head, int nodeid,
+					 uint32_t remid)
+{
+	struct dlm_lkb *lkb;
+
+	list_for_each_entry(lkb, head, lkb_statequeue) {
+		if (lkb->lkb_nodeid == nodeid && lkb->lkb_remid == remid)
+			return lkb;
+	}
+	return NULL;
+}
+
+static struct dlm_lkb *search_remid(struct dlm_rsb *r, int nodeid,
+				    uint32_t remid)
+{
+	struct dlm_lkb *lkb;
+
+	lkb = search_remid_list(&r->res_grantqueue, nodeid, remid);
+	if (lkb)
+		return lkb;
+	lkb = search_remid_list(&r->res_convertqueue, nodeid, remid);
+	if (lkb)
+		return lkb;
+	lkb = search_remid_list(&r->res_waitqueue, nodeid, remid);
+	if (lkb)
+		return lkb;
+	return NULL;
+}
+
+static int receive_rcom_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
+				  struct dlm_rsb *r, struct dlm_rcom *rc)
+{
+	struct rcom_lock *rl = (struct rcom_lock *) rc->rc_buf;
+	int lvblen;
+
+	lkb->lkb_nodeid = rc->rc_header.h_nodeid;
+	lkb->lkb_ownpid = rl->rl_ownpid;
+	lkb->lkb_remid = rl->rl_lkid;
+	lkb->lkb_exflags = rl->rl_exflags;
+	lkb->lkb_flags = rl->rl_flags & 0x0000FFFF;
+	lkb->lkb_flags |= DLM_IFL_MSTCPY;
+	lkb->lkb_lvbseq = rl->rl_lvbseq;
+	lkb->lkb_rqmode = rl->rl_rqmode;
+	lkb->lkb_grmode = rl->rl_grmode;
+	/* don't set lkb_status because add_lkb wants to itself */
+
+	lkb->lkb_bastaddr = (void *) (long) (rl->rl_asts & AST_BAST);
+	lkb->lkb_astaddr = (void *) (long) (rl->rl_asts & AST_COMP);
+
+	if (lkb->lkb_flags & DLM_IFL_RANGE) {
+		lkb->lkb_range = allocate_range(ls);
+		if (!lkb->lkb_range)
+			return -ENOMEM;
+		memcpy(lkb->lkb_range, rl->rl_range, 4*sizeof(uint64_t));
+	}
+
+	if (lkb->lkb_exflags & DLM_LKF_VALBLK) {
+		lkb->lkb_lvbptr = allocate_lvb(ls);
+		if (!lkb->lkb_lvbptr)
+			return -ENOMEM;
+		lvblen = rc->rc_header.h_length - sizeof(struct dlm_rcom) -
+			 sizeof(struct rcom_lock);
+		memcpy(lkb->lkb_lvbptr, rl->rl_lvb, lvblen);
+	}
+
+	/* Conversions between PR and CW (middle modes) need special handling.
+	   The real granted mode of these converting locks cannot be determined
+	   until all locks have been rebuilt on the rsb (recover_conversion) */
+
+	if (rl->rl_wait_type == DLM_MSG_CONVERT && middle_conversion(lkb)) {
+		rl->rl_status = DLM_LKSTS_CONVERT;
+		lkb->lkb_grmode = DLM_LOCK_IV;
+		rsb_set_flag(r, RSB_RECOVER_CONVERT);
+	}
+
+	return 0;
+}
+
+/* This lkb may have been recovered in a previous aborted recovery so we need
+   to check if the rsb already has an lkb with the given remote nodeid/lkid.
+   If so we just send back a standard reply.  If not, we create a new lkb with
+   the given values and send back our lkid.  We send back our lkid by sending
+   back the rcom_lock struct we got but with the remid field filled in. */
+
+int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
+{
+	struct rcom_lock *rl = (struct rcom_lock *) rc->rc_buf;
+	struct dlm_rsb *r;
+	struct dlm_lkb *lkb;
+	int error;
+
+	if (rl->rl_parent_lkid) {
+		error = -EOPNOTSUPP;
+		goto out;
+	}
+
+	error = find_rsb(ls, rl->rl_name, rl->rl_namelen, R_MASTER, &r);
+	if (error)
+		goto out;
+
+	lock_rsb(r);
+
+	lkb = search_remid(r, rc->rc_header.h_nodeid, rl->rl_lkid);
+	if (lkb) {
+		error = -EEXIST;
+		goto out_remid;
+	}
+
+	error = create_lkb(ls, &lkb);
+	if (error)
+		goto out_unlock;
+
+	error = receive_rcom_lock_args(ls, lkb, r, rc);
+	if (error) {
+		put_lkb(lkb);
+		goto out_unlock;
+	}
+
+	attach_lkb(r, lkb);
+	add_lkb(r, lkb, rl->rl_status);
+	error = 0;
+
+ out_remid:
+	/* this is the new value returned to the lock holder for
+	   saving in its process-copy lkb */
+	rl->rl_remid = lkb->lkb_id;
+
+ out_unlock:
+	unlock_rsb(r);
+	put_rsb(r);
+ out:
+	if (error)
+		log_print("recover_master_copy %d %x", error, rl->rl_lkid);
+	rl->rl_result = error;
+	return error;
+}
+
+int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
+{
+	struct rcom_lock *rl = (struct rcom_lock *) rc->rc_buf;
+	struct dlm_rsb *r;
+	struct dlm_lkb *lkb;
+	int error;
+
+	error = find_lkb(ls, rl->rl_lkid, &lkb);
+	if (error) {
+		log_error(ls, "recover_process_copy no lkid %x", rl->rl_lkid);
+		return error;
+	}
+
+	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
+
+	error = rl->rl_result;
+
+	r = lkb->lkb_resource;
+	hold_rsb(r);
+	lock_rsb(r);
+
+	switch (error) {
+	case -EEXIST:
+		log_debug(ls, "master copy exists %x", lkb->lkb_id);
+		/* fall through */
+	case 0:
+		lkb->lkb_remid = rl->rl_remid;
+		break;
+	default:
+		log_error(ls, "dlm_recover_process_copy unknown error %d %x",
+			  error, lkb->lkb_id);
+	}
+
+	/* an ack for dlm_recover_locks() which waits for replies from
+	   all the locks it sends to new masters */
+	dlm_recovered_lock(r);
+
+	unlock_rsb(r);
+	put_rsb(r);
+	put_lkb(lkb);
+
+	return 0;
+}
+

fs/dlm/lock.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __LOCK_DOT_H__
+#define __LOCK_DOT_H__
+
+void dlm_print_rsb(struct dlm_rsb *r);
+int dlm_receive_message(struct dlm_header *hd, int nodeid, int recovery);
+int dlm_modes_compat(int mode1, int mode2);
+int dlm_find_rsb(struct dlm_ls *ls, char *name, int namelen,
+	unsigned int flags, struct dlm_rsb **r_ret);
+void dlm_put_rsb(struct dlm_rsb *r);
+void dlm_hold_rsb(struct dlm_rsb *r);
+int dlm_put_lkb(struct dlm_lkb *lkb);
+void dlm_scan_rsbs(struct dlm_ls *ls);
+
+int dlm_purge_locks(struct dlm_ls *ls);
+void dlm_purge_mstcpy_locks(struct dlm_rsb *r);
+int dlm_grant_after_purge(struct dlm_ls *ls);
+int dlm_recover_waiters_post(struct dlm_ls *ls);
+void dlm_recover_waiters_pre(struct dlm_ls *ls);
+int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
+int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
+
+static inline int is_master(struct dlm_rsb *r)
+{
+	return !r->res_nodeid;
+}
+
+static inline void lock_rsb(struct dlm_rsb *r)
+{
+	down(&r->res_sem);
+}
+
+static inline void unlock_rsb(struct dlm_rsb *r)
+{
+	up(&r->res_sem);
+}
+
+#endif
+

fs/dlm/lockspace.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "recoverd.h"
+#include "ast.h"
+#include "dir.h"
+#include "lowcomms.h"
+#include "config.h"
+#include "memory.h"
+#include "lock.h"
+
+#ifdef CONFIG_DLM_DEBUG
+int dlm_create_debug_file(struct dlm_ls *ls);
+void dlm_delete_debug_file(struct dlm_ls *ls);
+#else
+static inline int dlm_create_debug_file(struct dlm_ls *ls) { return 0; }
+static inline void dlm_delete_debug_file(struct dlm_ls *ls) { }
+#endif
+
+static int			ls_count;
+static struct semaphore		ls_lock;
+static struct list_head		lslist;
+static spinlock_t		lslist_lock;
+static struct task_struct *	scand_task;
+
+
+static ssize_t dlm_control_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	ssize_t ret = len;
+	int n = simple_strtol(buf, NULL, 0);
+
+	switch (n) {
+	case 0:
+		dlm_ls_stop(ls);
+		break;
+	case 1:
+		dlm_ls_start(ls);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+static ssize_t dlm_event_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	ls->ls_uevent_result = simple_strtol(buf, NULL, 0);
+	set_bit(LSFL_UEVENT_WAIT, &ls->ls_flags);
+	wake_up(&ls->ls_uevent_wait);
+	return len;
+}
+
+static ssize_t dlm_id_show(struct dlm_ls *ls, char *buf)
+{
+	return sprintf(buf, "%u\n", ls->ls_global_id);
+}
+
+static ssize_t dlm_id_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	ls->ls_global_id = simple_strtoul(buf, NULL, 0);
+	return len;
+}
+
+struct dlm_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct dlm_ls *, char *);
+	ssize_t (*store)(struct dlm_ls *, const char *, size_t);
+};
+
+static struct dlm_attr dlm_attr_control = {
+	.attr  = {.name = "control", .mode = S_IWUSR},
+	.store = dlm_control_store
+};
+
+static struct dlm_attr dlm_attr_event = {
+	.attr  = {.name = "event_done", .mode = S_IWUSR},
+	.store = dlm_event_store
+};
+
+static struct dlm_attr dlm_attr_id = {
+	.attr  = {.name = "id", .mode = S_IRUGO | S_IWUSR},
+	.show  = dlm_id_show,
+	.store = dlm_id_store
+};
+
+static struct attribute *dlm_attrs[] = {
+	&dlm_attr_control.attr,
+	&dlm_attr_event.attr,
+	&dlm_attr_id.attr,
+	NULL,
+};
+
+static ssize_t dlm_attr_show(struct kobject *kobj, struct attribute *attr,
+			     char *buf)
+{
+	struct dlm_ls *ls  = container_of(kobj, struct dlm_ls, ls_kobj);
+	struct dlm_attr *a = container_of(attr, struct dlm_attr, attr);
+	return a->show ? a->show(ls, buf) : 0;
+}
+
+static ssize_t dlm_attr_store(struct kobject *kobj, struct attribute *attr,
+			      const char *buf, size_t len)
+{
+	struct dlm_ls *ls  = container_of(kobj, struct dlm_ls, ls_kobj);
+	struct dlm_attr *a = container_of(attr, struct dlm_attr, attr);
+	return a->store ? a->store(ls, buf, len) : len;
+}
+
+static struct sysfs_ops dlm_attr_ops = {
+	.show  = dlm_attr_show,
+	.store = dlm_attr_store,
+};
+
+static struct kobj_type dlm_ktype = {
+	.default_attrs = dlm_attrs,
+	.sysfs_ops     = &dlm_attr_ops,
+};
+
+static struct kset dlm_kset = {
+	.subsys = &kernel_subsys,
+	.kobj   = {.name = "dlm",},
+	.ktype  = &dlm_ktype,
+};
+
+static int kobject_setup(struct dlm_ls *ls)
+{
+	char lsname[DLM_LOCKSPACE_LEN];
+	int error;
+
+	memset(lsname, 0, DLM_LOCKSPACE_LEN);
+	snprintf(lsname, DLM_LOCKSPACE_LEN, "%s", ls->ls_name);
+
+	error = kobject_set_name(&ls->ls_kobj, "%s", lsname);
+	if (error)
+		return error;
+
+	ls->ls_kobj.kset = &dlm_kset;
+	ls->ls_kobj.ktype = &dlm_ktype;
+	return 0;
+}
+
+static int do_uevent(struct dlm_ls *ls, int in)
+{
+	int error;
+
+	if (in)
+		kobject_uevent(&ls->ls_kobj, KOBJ_ONLINE);
+	else
+		kobject_uevent(&ls->ls_kobj, KOBJ_OFFLINE);
+
+	error = wait_event_interruptible(ls->ls_uevent_wait,
+			test_and_clear_bit(LSFL_UEVENT_WAIT, &ls->ls_flags));
+	if (error)
+		goto out;
+
+	error = ls->ls_uevent_result;
+ out:
+	return error;
+}
+
+
+int dlm_lockspace_init(void)
+{
+	int error;
+
+	ls_count = 0;
+	init_MUTEX(&ls_lock);
+	INIT_LIST_HEAD(&lslist);
+	spin_lock_init(&lslist_lock);
+
+	error = kset_register(&dlm_kset);
+	if (error)
+		printk("dlm_lockspace_init: cannot register kset %d\n", error);
+	return error;
+}
+
+void dlm_lockspace_exit(void)
+{
+	kset_unregister(&dlm_kset);
+}
+
+static int dlm_scand(void *data)
+{
+	struct dlm_ls *ls;
+
+	while (!kthread_should_stop()) {
+		list_for_each_entry(ls, &lslist, ls_list)
+			dlm_scan_rsbs(ls);
+		schedule_timeout_interruptible(dlm_config.scan_secs * HZ);
+	}
+	return 0;
+}
+
+static int dlm_scand_start(void)
+{
+	struct task_struct *p;
+	int error = 0;
+
+	p = kthread_run(dlm_scand, NULL, "dlm_scand");
+	if (IS_ERR(p))
+		error = PTR_ERR(p);
+	else
+		scand_task = p;
+	return error;
+}
+
+static void dlm_scand_stop(void)
+{
+	kthread_stop(scand_task);
+}
+
+static struct dlm_ls *dlm_find_lockspace_name(char *name, int namelen)
+{
+	struct dlm_ls *ls;
+
+	spin_lock(&lslist_lock);
+
+	list_for_each_entry(ls, &lslist, ls_list) {
+		if (ls->ls_namelen == namelen &&
+		    memcmp(ls->ls_name, name, namelen) == 0)
+			goto out;
+	}
+	ls = NULL;
+ out:
+	spin_unlock(&lslist_lock);
+	return ls;
+}
+
+struct dlm_ls *dlm_find_lockspace_global(uint32_t id)
+{
+	struct dlm_ls *ls;
+
+	spin_lock(&lslist_lock);
+
+	list_for_each_entry(ls, &lslist, ls_list) {
+		if (ls->ls_global_id == id) {
+			ls->ls_count++;
+			goto out;
+		}
+	}
+	ls = NULL;
+ out:
+	spin_unlock(&lslist_lock);
+	return ls;
+}
+
+struct dlm_ls *dlm_find_lockspace_local(void *id)
+{
+	struct dlm_ls *ls = id;
+
+	spin_lock(&lslist_lock);
+	ls->ls_count++;
+	spin_unlock(&lslist_lock);
+	return ls;
+}
+
+void dlm_put_lockspace(struct dlm_ls *ls)
+{
+	spin_lock(&lslist_lock);
+	ls->ls_count--;
+	spin_unlock(&lslist_lock);
+}
+
+static void remove_lockspace(struct dlm_ls *ls)
+{
+	for (;;) {
+		spin_lock(&lslist_lock);
+		if (ls->ls_count == 0) {
+			list_del(&ls->ls_list);
+			spin_unlock(&lslist_lock);
+			return;
+		}
+		spin_unlock(&lslist_lock);
+		ssleep(1);
+	}
+}
+
+static int threads_start(void)
+{
+	int error;
+
+	/* Thread which process lock requests for all lockspace's */
+	error = dlm_astd_start();
+	if (error) {
+		log_print("cannot start dlm_astd thread %d", error);
+		goto fail;
+	}
+
+	error = dlm_scand_start();
+	if (error) {
+		log_print("cannot start dlm_scand thread %d", error);
+		goto astd_fail;
+	}
+
+	/* Thread for sending/receiving messages for all lockspace's */
+	error = dlm_lowcomms_start();
+	if (error) {
+		log_print("cannot start dlm lowcomms %d", error);
+		goto scand_fail;
+	}
+
+	return 0;
+
+ scand_fail:
+	dlm_scand_stop();
+ astd_fail:
+	dlm_astd_stop();
+ fail:
+	return error;
+}
+
+static void threads_stop(void)
+{
+	dlm_scand_stop();
+	dlm_lowcomms_stop();
+	dlm_astd_stop();
+}
+
+static int new_lockspace(char *name, int namelen, void **lockspace,
+			 uint32_t flags, int lvblen)
+{
+	struct dlm_ls *ls;
+	int i, size, error = -ENOMEM;
+
+	if (namelen > DLM_LOCKSPACE_LEN)
+		return -EINVAL;
+
+	if (!lvblen || (lvblen % 8))
+		return -EINVAL;
+
+	if (!try_module_get(THIS_MODULE))
+		return -EINVAL;
+
+	ls = dlm_find_lockspace_name(name, namelen);
+	if (ls) {
+		*lockspace = ls;
+		module_put(THIS_MODULE);
+		return -EEXIST;
+	}
+
+	ls = kmalloc(sizeof(struct dlm_ls) + namelen, GFP_KERNEL);
+	if (!ls)
+		goto out;
+	memset(ls, 0, sizeof(struct dlm_ls) + namelen);
+	memcpy(ls->ls_name, name, namelen);
+	ls->ls_namelen = namelen;
+	ls->ls_exflags = flags;
+	ls->ls_lvblen = lvblen;
+	ls->ls_count = 0;
+	ls->ls_flags = 0;
+
+	size = dlm_config.rsbtbl_size;
+	ls->ls_rsbtbl_size = size;
+
+	ls->ls_rsbtbl = kmalloc(sizeof(struct dlm_rsbtable) * size, GFP_KERNEL);
+	if (!ls->ls_rsbtbl)
+		goto out_lsfree;
+	for (i = 0; i < size; i++) {
+		INIT_LIST_HEAD(&ls->ls_rsbtbl[i].list);
+		INIT_LIST_HEAD(&ls->ls_rsbtbl[i].toss);
+		rwlock_init(&ls->ls_rsbtbl[i].lock);
+	}
+
+	size = dlm_config.lkbtbl_size;
+	ls->ls_lkbtbl_size = size;
+
+	ls->ls_lkbtbl = kmalloc(sizeof(struct dlm_lkbtable) * size, GFP_KERNEL);
+	if (!ls->ls_lkbtbl)
+		goto out_rsbfree;
+	for (i = 0; i < size; i++) {
+		INIT_LIST_HEAD(&ls->ls_lkbtbl[i].list);
+		rwlock_init(&ls->ls_lkbtbl[i].lock);
+		ls->ls_lkbtbl[i].counter = 1;
+	}
+
+	size = dlm_config.dirtbl_size;
+	ls->ls_dirtbl_size = size;
+
+	ls->ls_dirtbl = kmalloc(sizeof(struct dlm_dirtable) * size, GFP_KERNEL);
+	if (!ls->ls_dirtbl)
+		goto out_lkbfree;
+	for (i = 0; i < size; i++) {
+		INIT_LIST_HEAD(&ls->ls_dirtbl[i].list);
+		rwlock_init(&ls->ls_dirtbl[i].lock);
+	}
+
+	INIT_LIST_HEAD(&ls->ls_waiters);
+	init_MUTEX(&ls->ls_waiters_sem);
+
+	INIT_LIST_HEAD(&ls->ls_nodes);
+	INIT_LIST_HEAD(&ls->ls_nodes_gone);
+	ls->ls_num_nodes = 0;
+	ls->ls_low_nodeid = 0;
+	ls->ls_total_weight = 0;
+	ls->ls_node_array = NULL;
+
+	memset(&ls->ls_stub_rsb, 0, sizeof(struct dlm_rsb));
+	ls->ls_stub_rsb.res_ls = ls;
+
+	ls->ls_debug_dentry = NULL;
+
+	init_waitqueue_head(&ls->ls_uevent_wait);
+	ls->ls_uevent_result = 0;
+
+	ls->ls_recoverd_task = NULL;
+	init_MUTEX(&ls->ls_recoverd_active);
+	spin_lock_init(&ls->ls_recover_lock);
+	ls->ls_recover_status = 0;
+	ls->ls_recover_seq = 0;
+	ls->ls_recover_args = NULL;
+	init_rwsem(&ls->ls_in_recovery);
+	INIT_LIST_HEAD(&ls->ls_requestqueue);
+	init_MUTEX(&ls->ls_requestqueue_lock);
+
+	ls->ls_recover_buf = kmalloc(dlm_config.buffer_size, GFP_KERNEL);
+	if (!ls->ls_recover_buf)
+		goto out_dirfree;
+
+	INIT_LIST_HEAD(&ls->ls_recover_list);
+	spin_lock_init(&ls->ls_recover_list_lock);
+	ls->ls_recover_list_count = 0;
+	init_waitqueue_head(&ls->ls_wait_general);
+	INIT_LIST_HEAD(&ls->ls_root_list);
+	init_rwsem(&ls->ls_root_sem);
+
+	down_write(&ls->ls_in_recovery);
+
+	error = dlm_recoverd_start(ls);
+	if (error) {
+		log_error(ls, "can't start dlm_recoverd %d", error);
+		goto out_rcomfree;
+	}
+
+	spin_lock(&lslist_lock);
+	list_add(&ls->ls_list, &lslist);
+	spin_unlock(&lslist_lock);
+
+	dlm_create_debug_file(ls);
+
+	error = kobject_setup(ls);
+	if (error)
+		goto out_del;
+
+	error = kobject_register(&ls->ls_kobj);
+	if (error)
+		goto out_del;
+
+	error = do_uevent(ls, 1);
+	if (error)
+		goto out_unreg;
+
+	*lockspace = ls;
+	return 0;
+
+ out_unreg:
+	kobject_unregister(&ls->ls_kobj);
+ out_del:
+	dlm_delete_debug_file(ls);
+	spin_lock(&lslist_lock);
+	list_del(&ls->ls_list);
+	spin_unlock(&lslist_lock);
+	dlm_recoverd_stop(ls);
+ out_rcomfree:
+	kfree(ls->ls_recover_buf);
+ out_dirfree:
+	kfree(ls->ls_dirtbl);
+ out_lkbfree:
+	kfree(ls->ls_lkbtbl);
+ out_rsbfree:
+	kfree(ls->ls_rsbtbl);
+ out_lsfree:
+	kfree(ls);
+ out:
+	module_put(THIS_MODULE);
+	return error;
+}
+
+int dlm_new_lockspace(char *name, int namelen, void **lockspace,
+		      uint32_t flags, int lvblen)
+{
+	int error = 0;
+
+	down(&ls_lock);
+	if (!ls_count)
+		error = threads_start();
+	if (error)
+		goto out;
+
+	error = new_lockspace(name, namelen, lockspace, flags, lvblen);
+	if (!error)
+		ls_count++;
+ out:
+	up(&ls_lock);
+	return error;
+}
+
+/* Return 1 if the lockspace still has active remote locks,
+ *        2 if the lockspace still has active local locks.
+ */
+static int lockspace_busy(struct dlm_ls *ls)
+{
+	int i, lkb_found = 0;
+	struct dlm_lkb *lkb;
+
+	/* NOTE: We check the lockidtbl here rather than the resource table.
+	   This is because there may be LKBs queued as ASTs that have been
+	   unlinked from their RSBs and are pending deletion once the AST has
+	   been delivered */
+
+	for (i = 0; i < ls->ls_lkbtbl_size; i++) {
+		read_lock(&ls->ls_lkbtbl[i].lock);
+		if (!list_empty(&ls->ls_lkbtbl[i].list)) {
+			lkb_found = 1;
+			list_for_each_entry(lkb, &ls->ls_lkbtbl[i].list,
+					    lkb_idtbl_list) {
+				if (!lkb->lkb_nodeid) {
+					read_unlock(&ls->ls_lkbtbl[i].lock);
+					return 2;
+				}
+			}
+		}
+		read_unlock(&ls->ls_lkbtbl[i].lock);
+	}
+	return lkb_found;
+}
+
+static int release_lockspace(struct dlm_ls *ls, int force)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_rsb *rsb;
+	struct list_head *head;
+	int i;
+	int busy = lockspace_busy(ls);
+
+	if (busy > force)
+		return -EBUSY;
+
+	if (force < 3)
+		do_uevent(ls, 0);
+
+	dlm_recoverd_stop(ls);
+
+	remove_lockspace(ls);
+
+	dlm_delete_debug_file(ls);
+
+	dlm_astd_suspend();
+
+	kfree(ls->ls_recover_buf);
+
+	/*
+	 * Free direntry structs.
+	 */
+
+	dlm_dir_clear(ls);
+	kfree(ls->ls_dirtbl);
+
+	/*
+	 * Free all lkb's on lkbtbl[] lists.
+	 */
+
+	for (i = 0; i < ls->ls_lkbtbl_size; i++) {
+		head = &ls->ls_lkbtbl[i].list;
+		while (!list_empty(head)) {
+			lkb = list_entry(head->next, struct dlm_lkb,
+					 lkb_idtbl_list);
+
+			list_del(&lkb->lkb_idtbl_list);
+
+			dlm_del_ast(lkb);
+
+			if (lkb->lkb_lvbptr && lkb->lkb_flags & DLM_IFL_MSTCPY)
+				free_lvb(lkb->lkb_lvbptr);
+
+			free_lkb(lkb);
+		}
+	}
+	dlm_astd_resume();
+
+	kfree(ls->ls_lkbtbl);
+
+	/*
+	 * Free all rsb's on rsbtbl[] lists
+	 */
+
+	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
+		head = &ls->ls_rsbtbl[i].list;
+		while (!list_empty(head)) {
+			rsb = list_entry(head->next, struct dlm_rsb,
+					 res_hashchain);
+
+			list_del(&rsb->res_hashchain);
+			free_rsb(rsb);
+		}
+
+		head = &ls->ls_rsbtbl[i].toss;
+		while (!list_empty(head)) {
+			rsb = list_entry(head->next, struct dlm_rsb,
+					 res_hashchain);
+			list_del(&rsb->res_hashchain);
+			free_rsb(rsb);
+		}
+	}
+
+	kfree(ls->ls_rsbtbl);
+
+	/*
+	 * Free structures on any other lists
+	 */
+
+	kfree(ls->ls_recover_args);
+	dlm_clear_free_entries(ls);
+	dlm_clear_members(ls);
+	dlm_clear_members_gone(ls);
+	kfree(ls->ls_node_array);
+	kobject_unregister(&ls->ls_kobj);
+	kfree(ls);
+
+	down(&ls_lock);
+	ls_count--;
+	if (!ls_count)
+		threads_stop();
+	up(&ls_lock);
+
+	module_put(THIS_MODULE);
+	return 0;
+}
+
+/*
+ * Called when a system has released all its locks and is not going to use the
+ * lockspace any longer.  We free everything we're managing for this lockspace.
+ * Remaining nodes will go through the recovery process as if we'd died.  The
+ * lockspace must continue to function as usual, participating in recoveries,
+ * until this returns.
+ *
+ * Force has 4 possible values:
+ * 0 - don't destroy locksapce if it has any LKBs
+ * 1 - destroy lockspace if it has remote LKBs but not if it has local LKBs
+ * 2 - destroy lockspace regardless of LKBs
+ * 3 - destroy lockspace as part of a forced shutdown
+ */
+
+int dlm_release_lockspace(void *lockspace, int force)
+{
+	struct dlm_ls *ls;
+
+	ls = dlm_find_lockspace_local(lockspace);
+	if (!ls)
+		return -EINVAL;
+	dlm_put_lockspace(ls);
+	return release_lockspace(ls, force);
+}
+

fs/dlm/lockspace.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __LOCKSPACE_DOT_H__
+#define __LOCKSPACE_DOT_H__
+
+int dlm_lockspace_init(void);
+void dlm_lockspace_exit(void);
+struct dlm_ls *dlm_find_lockspace_global(uint32_t id);
+struct dlm_ls *dlm_find_lockspace_local(void *id);
+void dlm_put_lockspace(struct dlm_ls *ls);
+
+#endif				/* __LOCKSPACE_DOT_H__ */
+

fs/dlm/lowcomms.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+/*
+ * lowcomms.c
+ *
+ * This is the "low-level" comms layer.
+ *
+ * It is responsible for sending/receiving messages
+ * from other nodes in the cluster.
+ *
+ * Cluster nodes are referred to by their nodeids. nodeids are
+ * simply 32 bit numbers to the locking module - if they need to
+ * be expanded for the cluster infrastructure then that is it's
+ * responsibility. It is this layer's
+ * responsibility to resolve these into IP address or
+ * whatever it needs for inter-node communication.
+ *
+ * The comms level is two kernel threads that deal mainly with
+ * the receiving of messages from other nodes and passing them
+ * up to the mid-level comms layer (which understands the
+ * message format) for execution by the locking core, and
+ * a send thread which does all the setting up of connections
+ * to remote nodes and the sending of data. Threads are not allowed
+ * to send their own data because it may cause them to wait in times
+ * of high load. Also, this way, the sending thread can collect together
+ * messages bound for one node and send them in one block.
+ *
+ * I don't see any problem with the recv thread executing the locking
+ * code on behalf of remote processes as the locking code is
+ * short, efficient and never (well, hardly ever) waits.
+ *
+ */
+
+#include <asm/ioctls.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/sctp/user.h>
+#include <linux/pagemap.h>
+#include <linux/socket.h>
+#include <linux/idr.h>
+
+#include "dlm_internal.h"
+#include "lowcomms.h"
+#include "config.h"
+#include "midcomms.h"
+
+static struct sockaddr_storage *local_addr[DLM_MAX_ADDR_COUNT];
+static int			local_count;
+static int			local_nodeid;
+
+/* One of these per connected node */
+
+#define NI_INIT_PENDING 1
+#define NI_WRITE_PENDING 2
+
+struct nodeinfo {
+	spinlock_t		lock;
+	sctp_assoc_t		assoc_id;
+	unsigned long		flags;
+	struct list_head	write_list; /* nodes with pending writes */
+	struct list_head	writequeue; /* outgoing writequeue_entries */
+	spinlock_t		writequeue_lock;
+	int			nodeid;
+};
+
+static DEFINE_IDR(nodeinfo_idr);
+static struct rw_semaphore	nodeinfo_lock;
+static int			max_nodeid;
+
+struct cbuf {
+	unsigned		base;
+	unsigned		len;
+	unsigned		mask;
+};
+
+/* Just the one of these, now. But this struct keeps
+   the connection-specific variables together */
+
+#define CF_READ_PENDING 1
+
+struct connection {
+	struct socket          *sock;
+	unsigned long		flags;
+	struct page            *rx_page;
+	atomic_t		waiting_requests;
+	struct cbuf		cb;
+	int                     eagain_flag;
+};
+
+/* An entry waiting to be sent */
+
+struct writequeue_entry {
+	struct list_head	list;
+	struct page            *page;
+	int			offset;
+	int			len;
+	int			end;
+	int			users;
+	struct nodeinfo        *ni;
+};
+
+#define CBUF_ADD(cb, n) do { (cb)->len += n; } while(0)
+#define CBUF_EMPTY(cb) ((cb)->len == 0)
+#define CBUF_MAY_ADD(cb, n) (((cb)->len + (n)) < ((cb)->mask + 1))
+#define CBUF_DATA(cb) (((cb)->base + (cb)->len) & (cb)->mask)
+
+#define CBUF_INIT(cb, size) \
+do { \
+	(cb)->base = (cb)->len = 0; \
+	(cb)->mask = ((size)-1); \
+} while(0)
+
+#define CBUF_EAT(cb, n) \
+do { \
+	(cb)->len  -= (n); \
+	(cb)->base += (n); \
+	(cb)->base &= (cb)->mask; \
+} while(0)
+
+
+/* List of nodes which have writes pending */
+static struct list_head write_nodes;
+static spinlock_t write_nodes_lock;
+
+/* Maximum number of incoming messages to process before
+ * doing a schedule()
+ */
+#define MAX_RX_MSG_COUNT 25
+
+/* Manage daemons */
+static struct task_struct *recv_task;
+static struct task_struct *send_task;
+static wait_queue_head_t lowcomms_recv_wait;
+static atomic_t accepting;
+
+/* The SCTP connection */
+static struct connection sctp_con;
+
+
+static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
+{
+	struct sockaddr_storage addr;
+	int error;
+
+	if (!local_count)
+		return -1;
+
+	error = dlm_nodeid_to_addr(nodeid, &addr);
+	if (error)
+		return error;
+
+	if (local_addr[0]->ss_family == AF_INET) {
+	        struct sockaddr_in *in4  = (struct sockaddr_in *) &addr;
+		struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
+		ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
+	} else {
+	        struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &addr;
+		struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
+		memcpy(&ret6->sin6_addr, &in6->sin6_addr,
+		       sizeof(in6->sin6_addr));
+	}
+
+	return 0;
+}
+
+static struct nodeinfo *nodeid2nodeinfo(int nodeid, int alloc)
+{
+	struct nodeinfo *ni;
+	int r;
+	int n;
+
+	down_read(&nodeinfo_lock);
+	ni = idr_find(&nodeinfo_idr, nodeid);
+	up_read(&nodeinfo_lock);
+
+	if (!ni && alloc) {
+		down_write(&nodeinfo_lock);
+
+		ni = idr_find(&nodeinfo_idr, nodeid);
+		if (ni)
+			goto out_up;
+
+		r = idr_pre_get(&nodeinfo_idr, alloc);
+		if (!r)
+			goto out_up;
+
+		ni = kmalloc(sizeof(struct nodeinfo), alloc);
+		if (!ni)
+			goto out_up;
+
+		r = idr_get_new_above(&nodeinfo_idr, ni, nodeid, &n);
+		if (r) {
+			kfree(ni);
+			ni = NULL;
+			goto out_up;
+		}
+		if (n != nodeid) {
+			idr_remove(&nodeinfo_idr, n);
+			kfree(ni);
+			ni = NULL;
+			goto out_up;
+		}
+		memset(ni, 0, sizeof(struct nodeinfo));
+		spin_lock_init(&ni->lock);
+		INIT_LIST_HEAD(&ni->writequeue);
+		spin_lock_init(&ni->writequeue_lock);
+		ni->nodeid = nodeid;
+
+		if (nodeid > max_nodeid)
+			max_nodeid = nodeid;
+	out_up:
+		up_write(&nodeinfo_lock);
+	}
+
+	return ni;
+}
+
+/* Don't call this too often... */
+static struct nodeinfo *assoc2nodeinfo(sctp_assoc_t assoc)
+{
+	int i;
+	struct nodeinfo *ni;
+
+	for (i=1; i<=max_nodeid; i++) {
+		ni = nodeid2nodeinfo(i, 0);
+		if (ni && ni->assoc_id == assoc)
+			return ni;
+	}
+	return NULL;
+}
+
+/* Data or notification available on socket */
+static void lowcomms_data_ready(struct sock *sk, int count_unused)
+{
+	atomic_inc(&sctp_con.waiting_requests);
+	if (test_and_set_bit(CF_READ_PENDING, &sctp_con.flags))
+		return;
+
+	wake_up_interruptible(&lowcomms_recv_wait);
+}
+
+
+/* Add the port number to an IP6 or 4 sockaddr and return the address length.
+   Also padd out the struct with zeros to make comparisons meaningful */
+
+static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
+			  int *addr_len)
+{
+	struct sockaddr_in *local4_addr;
+	struct sockaddr_in6 *local6_addr;
+
+	if (!local_count)
+		return;
+
+	if (!port) {
+		if (local_addr[0]->ss_family == AF_INET) {
+			local4_addr = (struct sockaddr_in *)local_addr[0];
+			port = be16_to_cpu(local4_addr->sin_port);
+		} else {
+			local6_addr = (struct sockaddr_in6 *)local_addr[0];
+			port = be16_to_cpu(local6_addr->sin6_port);
+		}
+	}
+
+	saddr->ss_family = local_addr[0]->ss_family;
+	if (local_addr[0]->ss_family == AF_INET) {
+		struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
+		in4_addr->sin_port = cpu_to_be16(port);
+		memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
+		memset(in4_addr+1, 0, sizeof(struct sockaddr_storage) -
+				      sizeof(struct sockaddr_in));
+		*addr_len = sizeof(struct sockaddr_in);
+	} else {
+		struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
+		in6_addr->sin6_port = cpu_to_be16(port);
+		memset(in6_addr+1, 0, sizeof(struct sockaddr_storage) -
+				      sizeof(struct sockaddr_in6));
+		*addr_len = sizeof(struct sockaddr_in6);
+	}
+}
+
+/* Close the connection and tidy up */
+static void close_connection(void)
+{
+	if (sctp_con.sock) {
+		sock_release(sctp_con.sock);
+		sctp_con.sock = NULL;
+	}
+
+	if (sctp_con.rx_page) {
+		__free_page(sctp_con.rx_page);
+		sctp_con.rx_page = NULL;
+	}
+}
+
+/* We only send shutdown messages to nodes that are not part of the cluster */
+static void send_shutdown(sctp_assoc_t associd)
+{
+	static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+	struct msghdr outmessage;
+	struct cmsghdr *cmsg;
+	struct sctp_sndrcvinfo *sinfo;
+	int ret;
+
+	outmessage.msg_name = NULL;
+	outmessage.msg_namelen = 0;
+	outmessage.msg_control = outcmsg;
+	outmessage.msg_controllen = sizeof(outcmsg);
+	outmessage.msg_flags = MSG_EOR;
+
+	cmsg = CMSG_FIRSTHDR(&outmessage);
+	cmsg->cmsg_level = IPPROTO_SCTP;
+	cmsg->cmsg_type = SCTP_SNDRCV;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
+	outmessage.msg_controllen = cmsg->cmsg_len;
+	sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+	memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
+
+	sinfo->sinfo_flags |= MSG_EOF;
+	sinfo->sinfo_assoc_id = associd;
+
+	ret = kernel_sendmsg(sctp_con.sock, &outmessage, NULL, 0, 0);
+
+	if (ret != 0)
+		log_print("send EOF to node failed: %d", ret);
+}
+
+
+/* INIT failed but we don't know which node...
+   restart INIT on all pending nodes */
+static void init_failed(void)
+{
+	int i;
+	struct nodeinfo *ni;
+
+	for (i=1; i<=max_nodeid; i++) {
+		ni = nodeid2nodeinfo(i, 0);
+		if (!ni)
+			continue;
+
+		if (test_and_clear_bit(NI_INIT_PENDING, &ni->flags)) {
+			ni->assoc_id = 0;
+			if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+				spin_lock_bh(&write_nodes_lock);
+				list_add_tail(&ni->write_list, &write_nodes);
+				spin_unlock_bh(&write_nodes_lock);
+			}
+		}
+	}
+	wake_up_process(send_task);
+}
+
+/* Something happened to an association */
+static void process_sctp_notification(struct msghdr *msg, char *buf)
+{
+	union sctp_notification *sn = (union sctp_notification *)buf;
+
+	if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
+		switch (sn->sn_assoc_change.sac_state) {
+
+		case SCTP_COMM_UP:
+		case SCTP_RESTART:
+		{
+			/* Check that the new node is in the lockspace */
+			struct sctp_prim prim;
+			mm_segment_t fs;
+			int nodeid;
+			int prim_len, ret;
+			int addr_len;
+			struct nodeinfo *ni;
+
+			/* This seems to happen when we received a connection
+			 * too early... or something...  anyway, it happens but
+			 * we always seem to get a real message too, see
+			 * receive_from_sock */
+
+			if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
+				log_print("COMM_UP for invalid assoc ID %d",
+					 (int)sn->sn_assoc_change.sac_assoc_id);
+				init_failed();
+				return;
+			}
+			memset(&prim, 0, sizeof(struct sctp_prim));
+			prim_len = sizeof(struct sctp_prim);
+			prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
+
+			fs = get_fs();
+			set_fs(get_ds());
+			ret = sctp_con.sock->ops->getsockopt(sctp_con.sock,
+						IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
+						(char*)&prim, &prim_len);
+			set_fs(fs);
+			if (ret < 0) {
+				struct nodeinfo *ni;
+
+				log_print("getsockopt/sctp_primary_addr on "
+					  "new assoc %d failed : %d",
+				    (int)sn->sn_assoc_change.sac_assoc_id, ret);
+
+				/* Retry INIT later */
+				ni = assoc2nodeinfo(sn->sn_assoc_change.sac_assoc_id);
+				if (ni)
+					clear_bit(NI_INIT_PENDING, &ni->flags);
+				return;
+			}
+			make_sockaddr(&prim.ssp_addr, 0, &addr_len);
+			if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
+				log_print("reject connect from unknown addr");
+				send_shutdown(prim.ssp_assoc_id);
+				return;
+			}
+
+			ni = nodeid2nodeinfo(nodeid, GFP_KERNEL);
+			if (!ni)
+				return;
+
+			/* Save the assoc ID */
+			spin_lock(&ni->lock);
+			ni->assoc_id = sn->sn_assoc_change.sac_assoc_id;
+			spin_unlock(&ni->lock);
+
+			log_print("got new/restarted association %d nodeid %d",
+			       (int)sn->sn_assoc_change.sac_assoc_id, nodeid);
+
+			/* Send any pending writes */
+			clear_bit(NI_INIT_PENDING, &ni->flags);
+			if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+				spin_lock_bh(&write_nodes_lock);
+				list_add_tail(&ni->write_list, &write_nodes);
+				spin_unlock_bh(&write_nodes_lock);
+			}
+			wake_up_process(send_task);
+		}
+		break;
+
+		case SCTP_COMM_LOST:
+		case SCTP_SHUTDOWN_COMP:
+		{
+			struct nodeinfo *ni;
+
+			ni = assoc2nodeinfo(sn->sn_assoc_change.sac_assoc_id);
+			if (ni) {
+				spin_lock(&ni->lock);
+				ni->assoc_id = 0;
+				spin_unlock(&ni->lock);
+			}
+		}
+		break;
+
+		/* We don't know which INIT failed, so clear the PENDING flags
+		 * on them all.  if assoc_id is zero then it will then try
+		 * again */
+
+		case SCTP_CANT_STR_ASSOC:
+		{
+			log_print("Can't start SCTP association - retrying");
+			init_failed();
+		}
+		break;
+
+		default:
+			log_print("unexpected SCTP assoc change id=%d state=%d",
+				  (int)sn->sn_assoc_change.sac_assoc_id,
+				  sn->sn_assoc_change.sac_state);
+		}
+	}
+}
+
+/* Data received from remote end */
+static int receive_from_sock(void)
+{
+	int ret = 0;
+	struct msghdr msg;
+	struct kvec iov[2];
+	unsigned len;
+	int r;
+	struct sctp_sndrcvinfo *sinfo;
+	struct cmsghdr *cmsg;
+	struct nodeinfo *ni;
+
+	/* These two are marginally too big for stack allocation, but this
+	 * function is (currently) only called by dlm_recvd so static should be
+	 * OK.
+	 */
+	static struct sockaddr_storage msgname;
+	static char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+
+	if (sctp_con.sock == NULL)
+		goto out;
+
+	if (sctp_con.rx_page == NULL) {
+		/*
+		 * This doesn't need to be atomic, but I think it should
+		 * improve performance if it is.
+		 */
+		sctp_con.rx_page = alloc_page(GFP_ATOMIC);
+		if (sctp_con.rx_page == NULL)
+			goto out_resched;
+		CBUF_INIT(&sctp_con.cb, PAGE_CACHE_SIZE);
+	}
+
+	memset(&incmsg, 0, sizeof(incmsg));
+	memset(&msgname, 0, sizeof(msgname));
+
+	memset(incmsg, 0, sizeof(incmsg));
+	msg.msg_name = &msgname;
+	msg.msg_namelen = sizeof(msgname);
+	msg.msg_flags = 0;
+	msg.msg_control = incmsg;
+	msg.msg_controllen = sizeof(incmsg);
+
+	/* I don't see why this circular buffer stuff is necessary for SCTP
+	 * which is a packet-based protocol, but the whole thing breaks under
+	 * load without it! The overhead is minimal (and is in the TCP lowcomms
+	 * anyway, of course) so I'll leave it in until I can figure out what's
+	 * really happening.
+	 */
+
+	/*
+	 * iov[0] is the bit of the circular buffer between the current end
+	 * point (cb.base + cb.len) and the end of the buffer.
+	 */
+	iov[0].iov_len = sctp_con.cb.base - CBUF_DATA(&sctp_con.cb);
+	iov[0].iov_base = page_address(sctp_con.rx_page) +
+			  CBUF_DATA(&sctp_con.cb);
+	iov[1].iov_len = 0;
+
+	/*
+	 * iov[1] is the bit of the circular buffer between the start of the
+	 * buffer and the start of the currently used section (cb.base)
+	 */
+	if (CBUF_DATA(&sctp_con.cb) >= sctp_con.cb.base) {
+		iov[0].iov_len = PAGE_CACHE_SIZE - CBUF_DATA(&sctp_con.cb);
+		iov[1].iov_len = sctp_con.cb.base;
+		iov[1].iov_base = page_address(sctp_con.rx_page);
+		msg.msg_iovlen = 2;
+	}
+	len = iov[0].iov_len + iov[1].iov_len;
+
+	r = ret = kernel_recvmsg(sctp_con.sock, &msg, iov, 1, len,
+				 MSG_NOSIGNAL | MSG_DONTWAIT);
+	if (ret <= 0)
+		goto out_close;
+
+	msg.msg_control = incmsg;
+	msg.msg_controllen = sizeof(incmsg);
+	cmsg = CMSG_FIRSTHDR(&msg);
+	sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+
+	if (msg.msg_flags & MSG_NOTIFICATION) {
+		process_sctp_notification(&msg, page_address(sctp_con.rx_page));
+		return 0;
+	}
+
+	/* Is this a new association ? */
+	ni = nodeid2nodeinfo(le32_to_cpu(sinfo->sinfo_ppid), GFP_KERNEL);
+	if (ni) {
+		ni->assoc_id = sinfo->sinfo_assoc_id;
+		if (test_and_clear_bit(NI_INIT_PENDING, &ni->flags)) {
+
+			if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+				spin_lock_bh(&write_nodes_lock);
+				list_add_tail(&ni->write_list, &write_nodes);
+				spin_unlock_bh(&write_nodes_lock);
+			}
+			wake_up_process(send_task);
+		}
+	}
+
+	/* INIT sends a message with length of 1 - ignore it */
+	if (r == 1)
+		return 0;
+
+	CBUF_ADD(&sctp_con.cb, ret);
+	ret = dlm_process_incoming_buffer(cpu_to_le32(sinfo->sinfo_ppid),
+					  page_address(sctp_con.rx_page),
+					  sctp_con.cb.base, sctp_con.cb.len,
+					  PAGE_CACHE_SIZE);
+	if (ret < 0)
+		goto out_close;
+	CBUF_EAT(&sctp_con.cb, ret);
+
+      out:
+	ret = 0;
+	goto out_ret;
+
+      out_resched:
+	lowcomms_data_ready(sctp_con.sock->sk, 0);
+	ret = 0;
+	schedule();
+	goto out_ret;
+
+      out_close:
+	if (ret != -EAGAIN)
+		log_print("error reading from sctp socket: %d", ret);
+      out_ret:
+	return ret;
+}
+
+/* Bind to an IP address. SCTP allows multiple address so it can do multi-homing */
+static int add_bind_addr(struct sockaddr_storage *addr, int addr_len, int num)
+{
+	mm_segment_t fs;
+	int result = 0;
+
+	fs = get_fs();
+	set_fs(get_ds());
+	if (num == 1)
+		result = sctp_con.sock->ops->bind(sctp_con.sock,
+					(struct sockaddr *) addr, addr_len);
+	else
+		result = sctp_con.sock->ops->setsockopt(sctp_con.sock, SOL_SCTP,
+				SCTP_SOCKOPT_BINDX_ADD, (char *)addr, addr_len);
+	set_fs(fs);
+
+	if (result < 0)
+		log_print("Can't bind to port %d addr number %d",
+			  dlm_config.tcp_port, num);
+
+	return result;
+}
+
+static void init_local(void)
+{
+	struct sockaddr_storage sas, *addr;
+	int i;
+
+	local_nodeid = dlm_our_nodeid();
+
+	for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
+		if (dlm_our_addr(&sas, i))
+			break;
+
+		addr = kmalloc(sizeof(*addr), GFP_KERNEL);
+		if (!addr)
+			break;
+		memcpy(addr, &sas, sizeof(*addr));
+		local_addr[local_count++] = addr;
+	}
+}
+
+/* Initialise SCTP socket and bind to all interfaces */
+static int init_sock(void)
+{
+	mm_segment_t fs;
+	struct socket *sock = NULL;
+	struct sockaddr_storage localaddr;
+	struct sctp_event_subscribe subscribe;
+	int result = -EINVAL, num = 1, i, addr_len;
+
+	if (!local_count) {
+		init_local();
+		if (!local_count) {
+			log_print("no local IP address has been set");
+			goto out;
+		}
+	}
+
+	result = sock_create_kern(local_addr[0]->ss_family, SOCK_SEQPACKET,
+				  IPPROTO_SCTP, &sock);
+	if (result < 0) {
+		log_print("Can't create comms socket, check SCTP is loaded");
+		goto out;
+	}
+
+	/* Listen for events */
+	memset(&subscribe, 0, sizeof(subscribe));
+	subscribe.sctp_data_io_event = 1;
+	subscribe.sctp_association_event = 1;
+	subscribe.sctp_send_failure_event = 1;
+	subscribe.sctp_shutdown_event = 1;
+	subscribe.sctp_partial_delivery_event = 1;
+
+	fs = get_fs();
+	set_fs(get_ds());
+	result = sock->ops->setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
+				       (char *)&subscribe, sizeof(subscribe));
+	set_fs(fs);
+
+	if (result < 0) {
+		log_print("Failed to set SCTP_EVENTS on socket: result=%d",
+			  result);
+		goto create_delsock;
+	}
+
+	/* Init con struct */
+	sock->sk->sk_user_data = &sctp_con;
+	sctp_con.sock = sock;
+	sctp_con.sock->sk->sk_data_ready = lowcomms_data_ready;
+
+	/* Bind to all interfaces. */
+	for (i = 0; i < local_count; i++) {
+		memcpy(&localaddr, local_addr[i], sizeof(localaddr));
+		make_sockaddr(&localaddr, dlm_config.tcp_port, &addr_len);
+
+		result = add_bind_addr(&localaddr, addr_len, num);
+		if (result)
+			goto create_delsock;
+		++num;
+	}
+
+	result = sock->ops->listen(sock, 5);
+	if (result < 0) {
+		log_print("Can't set socket listening");
+		goto create_delsock;
+	}
+
+	return 0;
+
+ create_delsock:
+	sock_release(sock);
+	sctp_con.sock = NULL;
+ out:
+	return result;
+}
+
+
+static struct writequeue_entry *new_writequeue_entry(int allocation)
+{
+	struct writequeue_entry *entry;
+
+	entry = kmalloc(sizeof(struct writequeue_entry), allocation);
+	if (!entry)
+		return NULL;
+
+	entry->page = alloc_page(allocation);
+	if (!entry->page) {
+		kfree(entry);
+		return NULL;
+	}
+
+	entry->offset = 0;
+	entry->len = 0;
+	entry->end = 0;
+	entry->users = 0;
+
+	return entry;
+}
+
+void *dlm_lowcomms_get_buffer(int nodeid, int len, int allocation, char **ppc)
+{
+	struct writequeue_entry *e;
+	int offset = 0;
+	int users = 0;
+	struct nodeinfo *ni;
+
+	if (!atomic_read(&accepting))
+		return NULL;
+
+	ni = nodeid2nodeinfo(nodeid, allocation);
+	if (!ni)
+		return NULL;
+
+	spin_lock(&ni->writequeue_lock);
+	e = list_entry(ni->writequeue.prev, struct writequeue_entry, list);
+	if (((struct list_head *) e == &ni->writequeue) ||
+	    (PAGE_CACHE_SIZE - e->end < len)) {
+		e = NULL;
+	} else {
+		offset = e->end;
+		e->end += len;
+		users = e->users++;
+	}
+	spin_unlock(&ni->writequeue_lock);
+
+	if (e) {
+	      got_one:
+		if (users == 0)
+			kmap(e->page);
+		*ppc = page_address(e->page) + offset;
+		return e;
+	}
+
+	e = new_writequeue_entry(allocation);
+	if (e) {
+		spin_lock(&ni->writequeue_lock);
+		offset = e->end;
+		e->end += len;
+		e->ni = ni;
+		users = e->users++;
+		list_add_tail(&e->list, &ni->writequeue);
+		spin_unlock(&ni->writequeue_lock);
+		goto got_one;
+	}
+	return NULL;
+}
+
+void dlm_lowcomms_commit_buffer(void *arg)
+{
+	struct writequeue_entry *e = (struct writequeue_entry *) arg;
+	int users;
+	struct nodeinfo *ni = e->ni;
+
+	if (!atomic_read(&accepting))
+		return;
+
+	spin_lock(&ni->writequeue_lock);
+	users = --e->users;
+	if (users)
+		goto out;
+	e->len = e->end - e->offset;
+	kunmap(e->page);
+	spin_unlock(&ni->writequeue_lock);
+
+	if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+		spin_lock_bh(&write_nodes_lock);
+		list_add_tail(&ni->write_list, &write_nodes);
+		spin_unlock_bh(&write_nodes_lock);
+		wake_up_process(send_task);
+	}
+	return;
+
+      out:
+	spin_unlock(&ni->writequeue_lock);
+	return;
+}
+
+static void free_entry(struct writequeue_entry *e)
+{
+	__free_page(e->page);
+	kfree(e);
+}
+
+/* Initiate an SCTP association. In theory we could just use sendmsg() on
+   the first IP address and it should work, but this allows us to set up the
+   association before sending any valuable data that we can't afford to lose.
+   It also keeps the send path clean as it can now always use the association ID */
+static void initiate_association(int nodeid)
+{
+	struct sockaddr_storage rem_addr;
+	static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+	struct msghdr outmessage;
+	struct cmsghdr *cmsg;
+	struct sctp_sndrcvinfo *sinfo;
+	int ret;
+	int addrlen;
+	char buf[1];
+	struct kvec iov[1];
+	struct nodeinfo *ni;
+
+	log_print("Initiating association with node %d", nodeid);
+
+	ni = nodeid2nodeinfo(nodeid, GFP_KERNEL);
+	if (!ni)
+		return;
+
+	if (nodeid_to_addr(nodeid, (struct sockaddr *)&rem_addr)) {
+		log_print("no address for nodeid %d", nodeid);
+		return;
+	}
+
+	make_sockaddr(&rem_addr, dlm_config.tcp_port, &addrlen);
+
+	outmessage.msg_name = &rem_addr;
+	outmessage.msg_namelen = addrlen;
+	outmessage.msg_control = outcmsg;
+	outmessage.msg_controllen = sizeof(outcmsg);
+	outmessage.msg_flags = MSG_EOR;
+
+	iov[0].iov_base = buf;
+	iov[0].iov_len = 1;
+
+	/* Real INIT messages seem to cause trouble. Just send a 1 byte message
+	   we can afford to lose */
+	cmsg = CMSG_FIRSTHDR(&outmessage);
+	cmsg->cmsg_level = IPPROTO_SCTP;
+	cmsg->cmsg_type = SCTP_SNDRCV;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
+	sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+	memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
+	sinfo->sinfo_ppid = cpu_to_le32(local_nodeid);
+
+	outmessage.msg_controllen = cmsg->cmsg_len;
+	ret = kernel_sendmsg(sctp_con.sock, &outmessage, iov, 1, 1);
+	if (ret < 0) {
+		log_print("send INIT to node failed: %d", ret);
+		/* Try again later */
+		clear_bit(NI_INIT_PENDING, &ni->flags);
+	}
+}
+
+/* Send a message */
+static int send_to_sock(struct nodeinfo *ni)
+{
+	int ret = 0;
+	struct writequeue_entry *e;
+	int len, offset;
+	struct msghdr outmsg;
+	static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+	struct cmsghdr *cmsg;
+	struct sctp_sndrcvinfo *sinfo;
+	struct kvec iov;
+
+        /* See if we need to init an association before we start
+	   sending precious messages */
+	spin_lock(&ni->lock);
+	if (!ni->assoc_id && !test_and_set_bit(NI_INIT_PENDING, &ni->flags)) {
+		spin_unlock(&ni->lock);
+		initiate_association(ni->nodeid);
+		return 0;
+	}
+	spin_unlock(&ni->lock);
+
+	outmsg.msg_name = NULL; /* We use assoc_id */
+	outmsg.msg_namelen = 0;
+	outmsg.msg_control = outcmsg;
+	outmsg.msg_controllen = sizeof(outcmsg);
+	outmsg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL | MSG_EOR;
+
+	cmsg = CMSG_FIRSTHDR(&outmsg);
+	cmsg->cmsg_level = IPPROTO_SCTP;
+	cmsg->cmsg_type = SCTP_SNDRCV;
+	cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
+	sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+	memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
+	sinfo->sinfo_ppid = cpu_to_le32(local_nodeid);
+	sinfo->sinfo_assoc_id = ni->assoc_id;
+	outmsg.msg_controllen = cmsg->cmsg_len;
+
+	spin_lock(&ni->writequeue_lock);
+	for (;;) {
+		if (list_empty(&ni->writequeue))
+			break;
+		e = list_entry(ni->writequeue.next, struct writequeue_entry,
+			       list);
+		kmap(e->page);
+		len = e->len;
+		offset = e->offset;
+		BUG_ON(len == 0 && e->users == 0);
+		spin_unlock(&ni->writequeue_lock);
+
+		ret = 0;
+		if (len) {
+			iov.iov_base = page_address(e->page)+offset;
+			iov.iov_len = len;
+
+			ret = kernel_sendmsg(sctp_con.sock, &outmsg, &iov, 1,
+					     len);
+			if (ret == -EAGAIN) {
+				sctp_con.eagain_flag = 1;
+				goto out;
+			} else if (ret < 0)
+				goto send_error;
+		} else {
+			/* Don't starve people filling buffers */
+			schedule();
+		}
+
+		spin_lock(&ni->writequeue_lock);
+		e->offset += ret;
+		e->len -= ret;
+
+		if (e->len == 0 && e->users == 0) {
+			list_del(&e->list);
+			free_entry(e);
+			continue;
+		}
+	}
+	spin_unlock(&ni->writequeue_lock);
+ out:
+	return ret;
+
+ send_error:
+	log_print("Error sending to node %d %d", ni->nodeid, ret);
+	spin_lock(&ni->lock);
+	if (!test_and_set_bit(NI_INIT_PENDING, &ni->flags)) {
+		ni->assoc_id = 0;
+		spin_unlock(&ni->lock);
+		initiate_association(ni->nodeid);
+	} else
+		spin_unlock(&ni->lock);
+
+	return ret;
+}
+
+/* Try to send any messages that are pending */
+static void process_output_queue(void)
+{
+	struct list_head *list;
+	struct list_head *temp;
+
+	spin_lock_bh(&write_nodes_lock);
+	list_for_each_safe(list, temp, &write_nodes) {
+		struct nodeinfo *ni =
+		    list_entry(list, struct nodeinfo, write_list);
+		clear_bit(NI_WRITE_PENDING, &ni->flags);
+		list_del(&ni->write_list);
+
+		spin_unlock_bh(&write_nodes_lock);
+
+		send_to_sock(ni);
+		spin_lock_bh(&write_nodes_lock);
+	}
+	spin_unlock_bh(&write_nodes_lock);
+}
+
+/* Called after we've had -EAGAIN and been woken up */
+static void refill_write_queue(void)
+{
+	int i;
+
+	for (i=1; i<=max_nodeid; i++) {
+		struct nodeinfo *ni = nodeid2nodeinfo(i, 0);
+
+		if (ni) {
+			if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+				spin_lock_bh(&write_nodes_lock);
+				list_add_tail(&ni->write_list, &write_nodes);
+				spin_unlock_bh(&write_nodes_lock);
+			}
+		}
+	}
+}
+
+static void clean_one_writequeue(struct nodeinfo *ni)
+{
+	struct list_head *list;
+	struct list_head *temp;
+
+	spin_lock(&ni->writequeue_lock);
+	list_for_each_safe(list, temp, &ni->writequeue) {
+		struct writequeue_entry *e =
+			list_entry(list, struct writequeue_entry, list);
+		list_del(&e->list);
+		free_entry(e);
+	}
+	spin_unlock(&ni->writequeue_lock);
+}
+
+static void clean_writequeues(void)
+{
+	int i;
+
+	for (i=1; i<=max_nodeid; i++) {
+		struct nodeinfo *ni = nodeid2nodeinfo(i, 0);
+		if (ni)
+			clean_one_writequeue(ni);
+	}
+}
+
+
+static void dealloc_nodeinfo(void)
+{
+	int i;
+
+	for (i=1; i<=max_nodeid; i++) {
+		struct nodeinfo *ni = nodeid2nodeinfo(i, 0);
+		if (ni) {
+			idr_remove(&nodeinfo_idr, i);
+			kfree(ni);
+		}
+	}
+}
+
+static int write_list_empty(void)
+{
+	int status;
+
+	spin_lock_bh(&write_nodes_lock);
+	status = list_empty(&write_nodes);
+	spin_unlock_bh(&write_nodes_lock);
+
+	return status;
+}
+
+static int dlm_recvd(void *data)
+{
+	DECLARE_WAITQUEUE(wait, current);
+
+	while (!kthread_should_stop()) {
+		int count = 0;
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		add_wait_queue(&lowcomms_recv_wait, &wait);
+		if (!test_bit(CF_READ_PENDING, &sctp_con.flags))
+			schedule();
+		remove_wait_queue(&lowcomms_recv_wait, &wait);
+		set_current_state(TASK_RUNNING);
+
+		if (test_and_clear_bit(CF_READ_PENDING, &sctp_con.flags)) {
+			int ret;
+
+			do {
+				ret = receive_from_sock();
+
+				/* Don't starve out everyone else */
+				if (++count >= MAX_RX_MSG_COUNT) {
+					schedule();
+					count = 0;
+				}
+			} while (!kthread_should_stop() && ret >=0);
+		}
+		schedule();
+	}
+
+	return 0;
+}
+
+static int dlm_sendd(void *data)
+{
+	DECLARE_WAITQUEUE(wait, current);
+
+	add_wait_queue(sctp_con.sock->sk->sk_sleep, &wait);
+
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (write_list_empty())
+			schedule();
+		set_current_state(TASK_RUNNING);
+
+		if (sctp_con.eagain_flag) {
+			sctp_con.eagain_flag = 0;
+			refill_write_queue();
+		}
+		process_output_queue();
+	}
+
+	remove_wait_queue(sctp_con.sock->sk->sk_sleep, &wait);
+
+	return 0;
+}
+
+static void daemons_stop(void)
+{
+	kthread_stop(recv_task);
+	kthread_stop(send_task);
+}
+
+static int daemons_start(void)
+{
+	struct task_struct *p;
+	int error;
+
+	p = kthread_run(dlm_recvd, NULL, "dlm_recvd");
+	error = IS_ERR(p);
+       	if (error) {
+		log_print("can't start dlm_recvd %d", error);
+		return error;
+	}
+	recv_task = p;
+
+	p = kthread_run(dlm_sendd, NULL, "dlm_sendd");
+	error = IS_ERR(p);
+       	if (error) {
+		log_print("can't start dlm_sendd %d", error);
+		kthread_stop(recv_task);
+		return error;
+	}
+	send_task = p;
+
+	return 0;
+}
+
+/*
+ * This is quite likely to sleep...
+ */
+int dlm_lowcomms_start(void)
+{
+	int error;
+
+	spin_lock_init(&write_nodes_lock);
+	INIT_LIST_HEAD(&write_nodes);
+	init_rwsem(&nodeinfo_lock);
+
+	error = init_sock();
+	if (error)
+		goto fail_sock;
+	error = daemons_start();
+	if (error)
+		goto fail_sock;
+	atomic_set(&accepting, 1);
+	return 0;
+
+ fail_sock:
+	close_connection();
+	return error;
+}
+
+/* Set all the activity flags to prevent any socket activity. */
+
+void dlm_lowcomms_stop(void)
+{
+	atomic_set(&accepting, 0);
+	sctp_con.flags = 0x7;
+	daemons_stop();
+	clean_writequeues();
+	close_connection();
+	dealloc_nodeinfo();
+	max_nodeid = 0;
+}
+
+int dlm_lowcomms_init(void)
+{
+	init_waitqueue_head(&lowcomms_recv_wait);
+	return 0;
+}
+
+void dlm_lowcomms_exit(void)
+{
+	int i;
+
+	for (i = 0; i < local_count; i++)
+		kfree(local_addr[i]);
+	local_count = 0;
+	local_nodeid = 0;
+}
+

fs/dlm/lowcomms.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __LOWCOMMS_DOT_H__
+#define __LOWCOMMS_DOT_H__
+
+int dlm_lowcomms_init(void);
+void dlm_lowcomms_exit(void);
+int dlm_lowcomms_start(void);
+void dlm_lowcomms_stop(void);
+void *dlm_lowcomms_get_buffer(int nodeid, int len, int allocation, char **ppc);
+void dlm_lowcomms_commit_buffer(void *mh);
+
+#endif				/* __LOWCOMMS_DOT_H__ */
+

fs/dlm/lvb_table.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __LVB_TABLE_DOT_H__
+#define __LVB_TABLE_DOT_H__
+
+extern const int dlm_lvb_operations[8][8];
+
+#endif

fs/dlm/main.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "lock.h"
+#include "memory.h"
+#include "lowcomms.h"
+#include "config.h"
+
+#ifdef CONFIG_DLM_DEBUG
+int dlm_register_debugfs(void);
+void dlm_unregister_debugfs(void);
+#else
+static inline int dlm_register_debugfs(void) { return 0; }
+static inline void dlm_unregister_debugfs(void) { }
+#endif
+
+static int __init init_dlm(void)
+{
+	int error;
+
+	error = dlm_memory_init();
+	if (error)
+		goto out;
+
+	error = dlm_lockspace_init();
+	if (error)
+		goto out_mem;
+
+	error = dlm_config_init();
+	if (error)
+		goto out_lockspace;
+
+	error = dlm_register_debugfs();
+	if (error)
+		goto out_config;
+
+	error = dlm_lowcomms_init();
+	if (error)
+		goto out_debug;
+
+	printk("DLM (built %s %s) installed\n", __DATE__, __TIME__);
+
+	return 0;
+
+ out_debug:
+	dlm_unregister_debugfs();
+ out_config:
+	dlm_config_exit();
+ out_lockspace:
+	dlm_lockspace_exit();
+ out_mem:
+	dlm_memory_exit();
+ out:
+	return error;
+}
+
+static void __exit exit_dlm(void)
+{
+	dlm_lowcomms_exit();
+	dlm_config_exit();
+	dlm_memory_exit();
+	dlm_lockspace_exit();
+	dlm_unregister_debugfs();
+}
+
+module_init(init_dlm);
+module_exit(exit_dlm);
+
+MODULE_DESCRIPTION("Distributed Lock Manager");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+EXPORT_SYMBOL_GPL(dlm_new_lockspace);
+EXPORT_SYMBOL_GPL(dlm_release_lockspace);
+EXPORT_SYMBOL_GPL(dlm_lock);
+EXPORT_SYMBOL_GPL(dlm_unlock);
+

fs/dlm/member.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "recoverd.h"
+#include "recover.h"
+#include "lowcomms.h"
+#include "rcom.h"
+#include "config.h"
+
+/*
+ * Following called by dlm_recoverd thread
+ */
+
+static void add_ordered_member(struct dlm_ls *ls, struct dlm_member *new)
+{
+	struct dlm_member *memb = NULL;
+	struct list_head *tmp;
+	struct list_head *newlist = &new->list;
+	struct list_head *head = &ls->ls_nodes;
+
+	list_for_each(tmp, head) {
+		memb = list_entry(tmp, struct dlm_member, list);
+		if (new->nodeid < memb->nodeid)
+			break;
+	}
+
+	if (!memb)
+		list_add_tail(newlist, head);
+	else {
+		/* FIXME: can use list macro here */
+		newlist->prev = tmp->prev;
+		newlist->next = tmp;
+		tmp->prev->next = newlist;
+		tmp->prev = newlist;
+	}
+}
+
+static int dlm_add_member(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_member *memb;
+	int w;
+
+	memb = kmalloc(sizeof(struct dlm_member), GFP_KERNEL);
+	if (!memb)
+		return -ENOMEM;
+
+	w = dlm_node_weight(ls->ls_name, nodeid);
+	if (w < 0)
+		return w;
+
+	memb->nodeid = nodeid;
+	memb->weight = w;
+	add_ordered_member(ls, memb);
+	ls->ls_num_nodes++;
+	return 0;
+}
+
+static void dlm_remove_member(struct dlm_ls *ls, struct dlm_member *memb)
+{
+	list_move(&memb->list, &ls->ls_nodes_gone);
+	ls->ls_num_nodes--;
+}
+
+static int dlm_is_member(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_member *memb;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (memb->nodeid == nodeid)
+			return TRUE;
+	}
+	return FALSE;
+}
+
+int dlm_is_removed(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_member *memb;
+
+	list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
+		if (memb->nodeid == nodeid)
+			return TRUE;
+	}
+	return FALSE;
+}
+
+static void clear_memb_list(struct list_head *head)
+{
+	struct dlm_member *memb;
+
+	while (!list_empty(head)) {
+		memb = list_entry(head->next, struct dlm_member, list);
+		list_del(&memb->list);
+		kfree(memb);
+	}
+}
+
+void dlm_clear_members(struct dlm_ls *ls)
+{
+	clear_memb_list(&ls->ls_nodes);
+	ls->ls_num_nodes = 0;
+}
+
+void dlm_clear_members_gone(struct dlm_ls *ls)
+{
+	clear_memb_list(&ls->ls_nodes_gone);
+}
+
+static void make_member_array(struct dlm_ls *ls)
+{
+	struct dlm_member *memb;
+	int i, w, x = 0, total = 0, all_zero = 0, *array;
+
+	kfree(ls->ls_node_array);
+	ls->ls_node_array = NULL;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (memb->weight)
+			total += memb->weight;
+	}
+
+	/* all nodes revert to weight of 1 if all have weight 0 */
+
+	if (!total) {
+		total = ls->ls_num_nodes;
+		all_zero = 1;
+	}
+
+	ls->ls_total_weight = total;
+
+	array = kmalloc(sizeof(int) * total, GFP_KERNEL);
+	if (!array)
+		return;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (!all_zero && !memb->weight)
+			continue;
+
+		if (all_zero)
+			w = 1;
+		else
+			w = memb->weight;
+
+		DLM_ASSERT(x < total, printk("total %d x %d\n", total, x););
+
+		for (i = 0; i < w; i++)
+			array[x++] = memb->nodeid;
+	}
+
+	ls->ls_node_array = array;
+}
+
+/* send a status request to all members just to establish comms connections */
+
+static void ping_members(struct dlm_ls *ls)
+{
+	struct dlm_member *memb;
+	list_for_each_entry(memb, &ls->ls_nodes, list)
+		dlm_rcom_status(ls, memb->nodeid);
+}
+
+int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
+{
+	struct dlm_member *memb, *safe;
+	int i, error, found, pos = 0, neg = 0, low = -1;
+
+	/* move departed members from ls_nodes to ls_nodes_gone */
+
+	list_for_each_entry_safe(memb, safe, &ls->ls_nodes, list) {
+		found = FALSE;
+		for (i = 0; i < rv->node_count; i++) {
+			if (memb->nodeid == rv->nodeids[i]) {
+				found = TRUE;
+				break;
+			}
+		}
+
+		if (!found) {
+			neg++;
+			dlm_remove_member(ls, memb);
+			log_debug(ls, "remove member %d", memb->nodeid);
+		}
+	}
+
+	/* add new members to ls_nodes */
+
+	for (i = 0; i < rv->node_count; i++) {
+		if (dlm_is_member(ls, rv->nodeids[i]))
+			continue;
+		dlm_add_member(ls, rv->nodeids[i]);
+		pos++;
+		log_debug(ls, "add member %d", rv->nodeids[i]);
+	}
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (low == -1 || memb->nodeid < low)
+			low = memb->nodeid;
+	}
+	ls->ls_low_nodeid = low;
+
+	make_member_array(ls);
+	dlm_set_recover_status(ls, DLM_RS_NODES);
+	*neg_out = neg;
+
+	ping_members(ls);
+
+	error = dlm_recover_members_wait(ls);
+	log_debug(ls, "total members %d", ls->ls_num_nodes);
+	return error;
+}
+
+/*
+ * Following called from lockspace.c
+ */
+
+int dlm_ls_stop(struct dlm_ls *ls)
+{
+	int new;
+
+	/*
+	 * A stop cancels any recovery that's in progress (see RECOVERY_STOP,
+	 * dlm_recovery_stopped()) and prevents any new locks from being
+	 * processed (see RUNNING, dlm_locking_stopped()).
+	 */
+
+	spin_lock(&ls->ls_recover_lock);
+	set_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
+	new = test_and_clear_bit(LSFL_RUNNING, &ls->ls_flags);
+	ls->ls_recover_seq++;
+	spin_unlock(&ls->ls_recover_lock);
+
+	/*
+	 * This in_recovery lock does two things:
+	 *
+	 * 1) Keeps this function from returning until all threads are out
+	 *    of locking routines and locking is truely stopped.
+	 * 2) Keeps any new requests from being processed until it's unlocked
+	 *    when recovery is complete.
+	 */
+
+	if (new)
+		down_write(&ls->ls_in_recovery);
+
+	/*
+	 * The recoverd suspend/resume makes sure that dlm_recoverd (if
+	 * running) has noticed the clearing of RUNNING above and quit
+	 * processing the previous recovery.  This will be true for all nodes
+	 * before any nodes start the new recovery.
+	 */
+
+	dlm_recoverd_suspend(ls);
+	ls->ls_recover_status = 0;
+	dlm_recoverd_resume(ls);
+	return 0;
+}
+
+int dlm_ls_start(struct dlm_ls *ls)
+{
+	struct dlm_recover *rv = NULL, *rv_old;
+	int *ids = NULL;
+	int error, count;
+
+	rv = kmalloc(sizeof(struct dlm_recover), GFP_KERNEL);
+	if (!rv)
+		return -ENOMEM;
+	memset(rv, 0, sizeof(struct dlm_recover));
+
+	error = count = dlm_nodeid_list(ls->ls_name, &ids);
+	if (error <= 0)
+		goto fail;
+
+	spin_lock(&ls->ls_recover_lock);
+
+	/* the lockspace needs to be stopped before it can be started */
+
+	if (!dlm_locking_stopped(ls)) {
+		spin_unlock(&ls->ls_recover_lock);
+		log_error(ls, "start ignored: lockspace running");
+		error = -EINVAL;
+		goto fail;
+	}
+
+	rv->nodeids = ids;
+	rv->node_count = count;
+	rv->seq = ++ls->ls_recover_seq;
+	rv_old = ls->ls_recover_args;
+	ls->ls_recover_args = rv;
+	spin_unlock(&ls->ls_recover_lock);
+
+	if (rv_old) {
+		kfree(rv_old->nodeids);
+		kfree(rv_old);
+	}
+
+	dlm_recoverd_kick(ls);
+	return 0;
+
+ fail:
+	kfree(rv);
+	kfree(ids);
+	return error;
+}
+

fs/dlm/member.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __MEMBER_DOT_H__
+#define __MEMBER_DOT_H__
+
+int dlm_ls_stop(struct dlm_ls *ls);
+int dlm_ls_start(struct dlm_ls *ls);
+void dlm_clear_members(struct dlm_ls *ls);
+void dlm_clear_members_gone(struct dlm_ls *ls);
+int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv,int *neg_out);
+int dlm_is_removed(struct dlm_ls *ls, int nodeid);
+
+#endif                          /* __MEMBER_DOT_H__ */
+

fs/dlm/memory.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "config.h"
+#include "memory.h"
+
+static kmem_cache_t *lkb_cache;
+
+
+int dlm_memory_init(void)
+{
+	int ret = 0;
+
+	lkb_cache = kmem_cache_create("dlm_lkb", sizeof(struct dlm_lkb),
+				__alignof__(struct dlm_lkb), 0, NULL, NULL);
+	if (!lkb_cache)
+		ret = -ENOMEM;
+	return ret;
+}
+
+void dlm_memory_exit(void)
+{
+	if (lkb_cache)
+		kmem_cache_destroy(lkb_cache);
+}
+
+char *allocate_lvb(struct dlm_ls *ls)
+{
+	char *p;
+
+	p = kmalloc(ls->ls_lvblen, GFP_KERNEL);
+	if (p)
+		memset(p, 0, ls->ls_lvblen);
+	return p;
+}
+
+void free_lvb(char *p)
+{
+	kfree(p);
+}
+
+uint64_t *allocate_range(struct dlm_ls *ls)
+{
+	int ralen = 4*sizeof(uint64_t);
+	uint64_t *p;
+
+	p = kmalloc(ralen, GFP_KERNEL);
+	if (p)
+		memset(p, 0, ralen);
+	return p;
+}
+
+void free_range(uint64_t *p)
+{
+	kfree(p);
+}
+
+/* FIXME: have some minimal space built-in to rsb for the name and
+   kmalloc a separate name if needed, like dentries are done */
+
+struct dlm_rsb *allocate_rsb(struct dlm_ls *ls, int namelen)
+{
+	struct dlm_rsb *r;
+
+	DLM_ASSERT(namelen <= DLM_RESNAME_MAXLEN,);
+
+	r = kmalloc(sizeof(*r) + namelen, GFP_KERNEL);
+	if (r)
+		memset(r, 0, sizeof(*r) + namelen);
+	return r;
+}
+
+void free_rsb(struct dlm_rsb *r)
+{
+	if (r->res_lvbptr)
+		free_lvb(r->res_lvbptr);
+	kfree(r);
+}
+
+struct dlm_lkb *allocate_lkb(struct dlm_ls *ls)
+{
+	struct dlm_lkb *lkb;
+
+	lkb = kmem_cache_alloc(lkb_cache, GFP_KERNEL);
+	if (lkb)
+		memset(lkb, 0, sizeof(*lkb));
+	return lkb;
+}
+
+void free_lkb(struct dlm_lkb *lkb)
+{
+	kmem_cache_free(lkb_cache, lkb);
+}
+
+struct dlm_direntry *allocate_direntry(struct dlm_ls *ls, int namelen)
+{
+	struct dlm_direntry *de;
+
+	DLM_ASSERT(namelen <= DLM_RESNAME_MAXLEN,);
+
+	de = kmalloc(sizeof(*de) + namelen, GFP_KERNEL);
+	if (de)
+		memset(de, 0, sizeof(*de) + namelen);
+	return de;
+}
+
+void free_direntry(struct dlm_direntry *de)
+{
+	kfree(de);
+}
+

fs/dlm/memory.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __MEMORY_DOT_H__
+#define __MEMORY_DOT_H__
+
+int dlm_memory_init(void);
+void dlm_memory_exit(void);
+struct dlm_rsb *allocate_rsb(struct dlm_ls *ls, int namelen);
+void free_rsb(struct dlm_rsb *r);
+struct dlm_lkb *allocate_lkb(struct dlm_ls *ls);
+void free_lkb(struct dlm_lkb *l);
+struct dlm_direntry *allocate_direntry(struct dlm_ls *ls, int namelen);
+void free_direntry(struct dlm_direntry *de);
+char *allocate_lvb(struct dlm_ls *ls);
+void free_lvb(char *l);
+uint64_t *allocate_range(struct dlm_ls *ls);
+void free_range(uint64_t *l);
+
+#endif		/* __MEMORY_DOT_H__ */
+

fs/dlm/midcomms.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+/*
+ * midcomms.c
+ *
+ * This is the appallingly named "mid-level" comms layer.
+ *
+ * Its purpose is to take packets from the "real" comms layer,
+ * split them up into packets and pass them to the interested
+ * part of the locking mechanism.
+ *
+ * It also takes messages from the locking layer, formats them
+ * into packets and sends them to the comms layer.
+ */
+
+#include "dlm_internal.h"
+#include "lowcomms.h"
+#include "config.h"
+#include "rcom.h"
+#include "lock.h"
+#include "midcomms.h"
+
+
+static void copy_from_cb(void *dst, const void *base, unsigned offset,
+			 unsigned len, unsigned limit)
+{
+	unsigned copy = len;
+
+	if ((copy + offset) > limit)
+		copy = limit - offset;
+	memcpy(dst, base + offset, copy);
+	len -= copy;
+	if (len)
+		memcpy(dst + copy, base, len);
+}
+
+/*
+ * Called from the low-level comms layer to process a buffer of
+ * commands.
+ *
+ * Only complete messages are processed here, any "spare" bytes from
+ * the end of a buffer are saved and tacked onto the front of the next
+ * message that comes in. I doubt this will happen very often but we
+ * need to be able to cope with it and I don't want the task to be waiting
+ * for packets to come in when there is useful work to be done.
+ */
+
+int dlm_process_incoming_buffer(int nodeid, const void *base,
+				unsigned offset, unsigned len, unsigned limit)
+{
+	unsigned char __tmp[DLM_INBUF_LEN];
+	struct dlm_header *msg = (struct dlm_header *) __tmp;
+	int ret = 0;
+	int err = 0;
+	uint16_t msglen;
+	uint32_t lockspace;
+
+	while (len > sizeof(struct dlm_header)) {
+
+		/* Copy just the header to check the total length.  The
+		   message may wrap around the end of the buffer back to the
+		   start, so we need to use a temp buffer and copy_from_cb. */
+
+		copy_from_cb(msg, base, offset, sizeof(struct dlm_header),
+			     limit);
+
+		msglen = le16_to_cpu(msg->h_length);
+		lockspace = msg->h_lockspace;
+
+		err = -EINVAL;
+		if (msglen < sizeof(struct dlm_header))
+			break;
+		err = -E2BIG;
+		if (msglen > dlm_config.buffer_size) {
+			log_print("message size %d from %d too big, buf len %d",
+				  msglen, nodeid, len);
+			break;
+		}
+		err = 0;
+
+		/* If only part of the full message is contained in this
+		   buffer, then do nothing and wait for lowcomms to call
+		   us again later with more data.  We return 0 meaning
+		   we've consumed none of the input buffer. */
+
+		if (msglen > len)
+			break;
+
+		/* Allocate a larger temp buffer if the full message won't fit
+		   in the buffer on the stack (which should work for most
+		   ordinary messages). */
+
+		if (msglen > sizeof(__tmp) &&
+		    msg == (struct dlm_header *) __tmp) {
+			msg = kmalloc(dlm_config.buffer_size, GFP_KERNEL);
+			if (msg == NULL)
+				return ret;
+		}
+
+		copy_from_cb(msg, base, offset, msglen, limit);
+
+		BUG_ON(lockspace != msg->h_lockspace);
+
+		ret += msglen;
+		offset += msglen;
+		offset &= (limit - 1);
+		len -= msglen;
+
+		switch (msg->h_cmd) {
+		case DLM_MSG:
+			dlm_receive_message(msg, nodeid, FALSE);
+			break;
+
+		case DLM_RCOM:
+			dlm_receive_rcom(msg, nodeid);
+			break;
+
+		default:
+			log_print("unknown msg type %x from %u: %u %u %u %u",
+				  msg->h_cmd, nodeid, msglen, len, offset, ret);
+		}
+	}
+
+	if (msg != (struct dlm_header *) __tmp)
+		kfree(msg);
+
+	return err ? err : ret;
+}
+

fs/dlm/midcomms.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __MIDCOMMS_DOT_H__
+#define __MIDCOMMS_DOT_H__
+
+int dlm_process_incoming_buffer(int nodeid, const void *base, unsigned offset,
+				unsigned len, unsigned limit);
+
+#endif				/* __MIDCOMMS_DOT_H__ */
+

fs/dlm/rcom.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "lowcomms.h"
+#include "midcomms.h"
+#include "rcom.h"
+#include "recover.h"
+#include "dir.h"
+#include "config.h"
+#include "memory.h"
+#include "lock.h"
+#include "util.h"
+
+
+static int rcom_response(struct dlm_ls *ls)
+{
+	return test_bit(LSFL_RCOM_READY, &ls->ls_flags);
+}
+
+static int create_rcom(struct dlm_ls *ls, int to_nodeid, int type, int len,
+		       struct dlm_rcom **rc_ret, struct dlm_mhandle **mh_ret)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	char *mb;
+	int mb_len = sizeof(struct dlm_rcom) + len;
+
+	mh = dlm_lowcomms_get_buffer(to_nodeid, mb_len, GFP_KERNEL, &mb);
+	if (!mh) {
+		log_print("create_rcom to %d type %d len %d ENOBUFS",
+			  to_nodeid, type, len);
+		return -ENOBUFS;
+	}
+	memset(mb, 0, mb_len);
+
+	rc = (struct dlm_rcom *) mb;
+
+	rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+	rc->rc_header.h_lockspace = ls->ls_global_id;
+	rc->rc_header.h_nodeid = dlm_our_nodeid();
+	rc->rc_header.h_length = mb_len;
+	rc->rc_header.h_cmd = DLM_RCOM;
+
+	rc->rc_type = type;
+
+	*mh_ret = mh;
+	*rc_ret = rc;
+	return 0;
+}
+
+static void send_rcom(struct dlm_ls *ls, struct dlm_mhandle *mh,
+		      struct dlm_rcom *rc)
+{
+	dlm_rcom_out(rc);
+	dlm_lowcomms_commit_buffer(mh);
+}
+
+/* When replying to a status request, a node also sends back its
+   configuration values.  The requesting node then checks that the remote
+   node is configured the same way as itself. */
+
+static void make_config(struct dlm_ls *ls, struct rcom_config *rf)
+{
+	rf->rf_lvblen = ls->ls_lvblen;
+	rf->rf_lsflags = ls->ls_exflags;
+}
+
+static int check_config(struct dlm_ls *ls, struct rcom_config *rf, int nodeid)
+{
+	if (rf->rf_lvblen != ls->ls_lvblen ||
+	    rf->rf_lsflags != ls->ls_exflags) {
+		log_error(ls, "config mismatch: %d,%x nodeid %d: %d,%x",
+			  ls->ls_lvblen, ls->ls_exflags,
+			  nodeid, rf->rf_lvblen, rf->rf_lsflags);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int dlm_rcom_status(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error = 0;
+
+	memset(ls->ls_recover_buf, 0, dlm_config.buffer_size);
+
+	if (nodeid == dlm_our_nodeid()) {
+		rc = (struct dlm_rcom *) ls->ls_recover_buf;
+		rc->rc_result = dlm_recover_status(ls);
+		goto out;
+	}
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS, 0, &rc, &mh);
+	if (error)
+		goto out;
+
+	send_rcom(ls, mh, rc);
+
+	error = dlm_wait_function(ls, &rcom_response);
+	clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
+	if (error)
+		goto out;
+
+	rc = (struct dlm_rcom *) ls->ls_recover_buf;
+
+	if (rc->rc_result == -ESRCH) {
+		/* we pretend the remote lockspace exists with 0 status */
+		log_debug(ls, "remote node %d not ready", nodeid);
+		rc->rc_result = 0;
+	} else
+		error = check_config(ls, (struct rcom_config *) rc->rc_buf,
+				     nodeid);
+	/* the caller looks at rc_result for the remote recovery status */
+ out:
+	return error;
+}
+
+static void receive_rcom_status(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, nodeid = rc_in->rc_header.h_nodeid;
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_STATUS_REPLY,
+			    sizeof(struct rcom_config), &rc, &mh);
+	if (error)
+		return;
+	rc->rc_result = dlm_recover_status(ls);
+	make_config(ls, (struct rcom_config *) rc->rc_buf);
+
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_status_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
+	set_bit(LSFL_RCOM_READY, &ls->ls_flags);
+	wake_up(&ls->ls_wait_general);
+}
+
+int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name, int last_len)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error = 0, len = sizeof(struct dlm_rcom);
+
+	memset(ls->ls_recover_buf, 0, dlm_config.buffer_size);
+
+	if (nodeid == dlm_our_nodeid()) {
+		dlm_copy_master_names(ls, last_name, last_len,
+		                      ls->ls_recover_buf + len,
+		                      dlm_config.buffer_size - len, nodeid);
+		goto out;
+	}
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES, last_len, &rc, &mh);
+	if (error)
+		goto out;
+	memcpy(rc->rc_buf, last_name, last_len);
+
+	send_rcom(ls, mh, rc);
+
+	error = dlm_wait_function(ls, &rcom_response);
+	clear_bit(LSFL_RCOM_READY, &ls->ls_flags);
+ out:
+	return error;
+}
+
+static void receive_rcom_names(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, inlen, outlen;
+	int nodeid = rc_in->rc_header.h_nodeid;
+	uint32_t status = dlm_recover_status(ls);
+
+	/*
+	 * We can't run dlm_dir_rebuild_send (which uses ls_nodes) while
+	 * dlm_recoverd is running ls_nodes_reconfig (which changes ls_nodes).
+	 * It could only happen in rare cases where we get a late NAMES
+	 * message from a previous instance of recovery.
+	 */
+
+	if (!(status & DLM_RS_NODES)) {
+		log_debug(ls, "ignoring RCOM_NAMES from %u", nodeid);
+		return;
+	}
+
+	nodeid = rc_in->rc_header.h_nodeid;
+	inlen = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
+	outlen = dlm_config.buffer_size - sizeof(struct dlm_rcom);
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_NAMES_REPLY, outlen, &rc, &mh);
+	if (error)
+		return;
+
+	dlm_copy_master_names(ls, rc_in->rc_buf, inlen, rc->rc_buf, outlen,
+			      nodeid);
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_names_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	memcpy(ls->ls_recover_buf, rc_in, rc_in->rc_header.h_length);
+	set_bit(LSFL_RCOM_READY, &ls->ls_flags);
+	wake_up(&ls->ls_wait_general);
+}
+
+int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	struct dlm_ls *ls = r->res_ls;
+	int error;
+
+	error = create_rcom(ls, dir_nodeid, DLM_RCOM_LOOKUP, r->res_length,
+			    &rc, &mh);
+	if (error)
+		goto out;
+	memcpy(rc->rc_buf, r->res_name, r->res_length);
+	rc->rc_id = (unsigned long) r;
+
+	send_rcom(ls, mh, rc);
+ out:
+	return error;
+}
+
+static void receive_rcom_lookup(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, ret_nodeid, nodeid = rc_in->rc_header.h_nodeid;
+	int len = rc_in->rc_header.h_length - sizeof(struct dlm_rcom);
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_LOOKUP_REPLY, 0, &rc, &mh);
+	if (error)
+		return;
+
+	error = dlm_dir_lookup(ls, nodeid, rc_in->rc_buf, len, &ret_nodeid);
+	if (error)
+		ret_nodeid = error;
+	rc->rc_result = ret_nodeid;
+	rc->rc_id = rc_in->rc_id;
+
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_lookup_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	dlm_recover_master_reply(ls, rc_in);
+}
+
+static void pack_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb,
+			   struct rcom_lock *rl)
+{
+	memset(rl, 0, sizeof(*rl));
+
+	rl->rl_ownpid = lkb->lkb_ownpid;
+	rl->rl_lkid = lkb->lkb_id;
+	rl->rl_exflags = lkb->lkb_exflags;
+	rl->rl_flags = lkb->lkb_flags;
+	rl->rl_lvbseq = lkb->lkb_lvbseq;
+	rl->rl_rqmode = lkb->lkb_rqmode;
+	rl->rl_grmode = lkb->lkb_grmode;
+	rl->rl_status = lkb->lkb_status;
+	rl->rl_wait_type = lkb->lkb_wait_type;
+
+	if (lkb->lkb_bastaddr)
+		rl->rl_asts |= AST_BAST;
+	if (lkb->lkb_astaddr)
+		rl->rl_asts |= AST_COMP;
+
+	if (lkb->lkb_range)
+		memcpy(rl->rl_range, lkb->lkb_range, 4*sizeof(uint64_t));
+
+	rl->rl_namelen = r->res_length;
+	memcpy(rl->rl_name, r->res_name, r->res_length);
+
+	/* FIXME: might we have an lvb without DLM_LKF_VALBLK set ?
+	   If so, receive_rcom_lock_args() won't take this copy. */
+
+	if (lkb->lkb_lvbptr)
+		memcpy(rl->rl_lvb, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
+}
+
+int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
+{
+	struct dlm_ls *ls = r->res_ls;
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	struct rcom_lock *rl;
+	int error, len = sizeof(struct rcom_lock);
+
+	if (lkb->lkb_lvbptr)
+		len += ls->ls_lvblen;
+
+	error = create_rcom(ls, r->res_nodeid, DLM_RCOM_LOCK, len, &rc, &mh);
+	if (error)
+		goto out;
+
+	rl = (struct rcom_lock *) rc->rc_buf;
+	pack_rcom_lock(r, lkb, rl);
+	rc->rc_id = (unsigned long) r;
+
+	send_rcom(ls, mh, rc);
+ out:
+	return error;
+}
+
+static void receive_rcom_lock(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	int error, nodeid = rc_in->rc_header.h_nodeid;
+
+	dlm_recover_master_copy(ls, rc_in);
+
+	error = create_rcom(ls, nodeid, DLM_RCOM_LOCK_REPLY,
+			    sizeof(struct rcom_lock), &rc, &mh);
+	if (error)
+		return;
+
+	/* We send back the same rcom_lock struct we received, but
+	   dlm_recover_master_copy() has filled in rl_remid and rl_result */
+
+	memcpy(rc->rc_buf, rc_in->rc_buf, sizeof(struct rcom_lock));
+	rc->rc_id = rc_in->rc_id;
+
+	send_rcom(ls, mh, rc);
+}
+
+static void receive_rcom_lock_reply(struct dlm_ls *ls, struct dlm_rcom *rc_in)
+{
+	uint32_t status = dlm_recover_status(ls);
+
+	if (!(status & DLM_RS_DIR)) {
+		log_debug(ls, "ignoring RCOM_LOCK_REPLY from %u",
+			  rc_in->rc_header.h_nodeid);
+		return;
+	}
+
+	dlm_recover_process_copy(ls, rc_in);
+}
+
+static int send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
+{
+	struct dlm_rcom *rc;
+	struct dlm_mhandle *mh;
+	char *mb;
+	int mb_len = sizeof(struct dlm_rcom);
+
+	mh = dlm_lowcomms_get_buffer(nodeid, mb_len, GFP_KERNEL, &mb);
+	if (!mh)
+		return -ENOBUFS;
+	memset(mb, 0, mb_len);
+
+	rc = (struct dlm_rcom *) mb;
+
+	rc->rc_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+	rc->rc_header.h_lockspace = rc_in->rc_header.h_lockspace;
+	rc->rc_header.h_nodeid = dlm_our_nodeid();
+	rc->rc_header.h_length = mb_len;
+	rc->rc_header.h_cmd = DLM_RCOM;
+
+	rc->rc_type = DLM_RCOM_STATUS_REPLY;
+	rc->rc_result = -ESRCH;
+
+	dlm_rcom_out(rc);
+	dlm_lowcomms_commit_buffer(mh);
+
+	return 0;
+}
+
+/* Called by dlm_recvd; corresponds to dlm_receive_message() but special
+   recovery-only comms are sent through here. */
+
+void dlm_receive_rcom(struct dlm_header *hd, int nodeid)
+{
+	struct dlm_rcom *rc = (struct dlm_rcom *) hd;
+	struct dlm_ls *ls;
+
+	dlm_rcom_in(rc);
+
+	/* If the lockspace doesn't exist then still send a status message
+	   back; it's possible that it just doesn't have its global_id yet. */
+
+	ls = dlm_find_lockspace_global(hd->h_lockspace);
+	if (!ls) {
+		log_print("lockspace %x from %d not found",
+			  hd->h_lockspace, nodeid);
+		send_ls_not_ready(nodeid, rc);
+		return;
+	}
+
+	if (dlm_recovery_stopped(ls) && (rc->rc_type != DLM_RCOM_STATUS)) {
+		log_error(ls, "ignoring recovery message %x from %d",
+			  rc->rc_type, nodeid);
+		goto out;
+	}
+
+	if (nodeid != rc->rc_header.h_nodeid) {
+		log_error(ls, "bad rcom nodeid %d from %d",
+			  rc->rc_header.h_nodeid, nodeid);
+		goto out;
+	}
+
+	switch (rc->rc_type) {
+	case DLM_RCOM_STATUS:
+		receive_rcom_status(ls, rc);
+		break;
+
+	case DLM_RCOM_NAMES:
+		receive_rcom_names(ls, rc);
+		break;
+
+	case DLM_RCOM_LOOKUP:
+		receive_rcom_lookup(ls, rc);
+		break;
+
+	case DLM_RCOM_LOCK:
+		receive_rcom_lock(ls, rc);
+		break;
+
+	case DLM_RCOM_STATUS_REPLY:
+		receive_rcom_status_reply(ls, rc);
+		break;
+
+	case DLM_RCOM_NAMES_REPLY:
+		receive_rcom_names_reply(ls, rc);
+		break;
+
+	case DLM_RCOM_LOOKUP_REPLY:
+		receive_rcom_lookup_reply(ls, rc);
+		break;
+
+	case DLM_RCOM_LOCK_REPLY:
+		receive_rcom_lock_reply(ls, rc);
+		break;
+
+	default:
+		DLM_ASSERT(0, printk("rc_type=%x\n", rc->rc_type););
+	}
+ out:
+	dlm_put_lockspace(ls);
+}
+

fs/dlm/rcom.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __RCOM_DOT_H__
+#define __RCOM_DOT_H__
+
+int dlm_rcom_status(struct dlm_ls *ls, int nodeid);
+int dlm_rcom_names(struct dlm_ls *ls, int nodeid, char *last_name,int last_len);
+int dlm_send_rcom_lookup(struct dlm_rsb *r, int dir_nodeid);
+int dlm_send_rcom_lock(struct dlm_rsb *r, struct dlm_lkb *lkb);
+void dlm_receive_rcom(struct dlm_header *hd, int nodeid);
+
+#endif
+

fs/dlm/recover.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "dir.h"
+#include "config.h"
+#include "ast.h"
+#include "memory.h"
+#include "rcom.h"
+#include "lock.h"
+#include "lowcomms.h"
+#include "member.h"
+#include "recover.h"
+
+
+/*
+ * Recovery waiting routines: these functions wait for a particular reply from
+ * a remote node, or for the remote node to report a certain status.  They need
+ * to abort if the lockspace is stopped indicating a node has failed (perhaps
+ * the one being waited for).
+ */
+
+/*
+ * Wait until given function returns non-zero or lockspace is stopped
+ * (LS_RECOVERY_STOP set due to failure of a node in ls_nodes).  When another
+ * function thinks it could have completed the waited-on task, they should wake
+ * up ls_wait_general to get an immediate response rather than waiting for the
+ * timer to detect the result.  A timer wakes us up periodically while waiting
+ * to see if we should abort due to a node failure.  This should only be called
+ * by the dlm_recoverd thread.
+ */
+
+static void dlm_wait_timer_fn(unsigned long data)
+{
+	struct dlm_ls *ls = (struct dlm_ls *) data;
+	mod_timer(&ls->ls_timer, jiffies + (dlm_config.recover_timer * HZ));
+	wake_up(&ls->ls_wait_general);
+}
+
+int dlm_wait_function(struct dlm_ls *ls, int (*testfn) (struct dlm_ls *ls))
+{
+	int error = 0;
+
+	init_timer(&ls->ls_timer);
+	ls->ls_timer.function = dlm_wait_timer_fn;
+	ls->ls_timer.data = (long) ls;
+	ls->ls_timer.expires = jiffies + (dlm_config.recover_timer * HZ);
+	add_timer(&ls->ls_timer);
+
+	wait_event(ls->ls_wait_general, testfn(ls) || dlm_recovery_stopped(ls));
+	del_timer_sync(&ls->ls_timer);
+
+	if (dlm_recovery_stopped(ls)) {
+		log_debug(ls, "dlm_wait_function aborted");
+		error = -EINTR;
+	}
+	return error;
+}
+
+/*
+ * An efficient way for all nodes to wait for all others to have a certain
+ * status.  The node with the lowest nodeid polls all the others for their
+ * status (wait_status_all) and all the others poll the node with the low id
+ * for its accumulated result (wait_status_low).  When all nodes have set
+ * status flag X, then status flag X_ALL will be set on the low nodeid.
+ */
+
+uint32_t dlm_recover_status(struct dlm_ls *ls)
+{
+	uint32_t status;
+	spin_lock(&ls->ls_recover_lock);
+	status = ls->ls_recover_status;
+	spin_unlock(&ls->ls_recover_lock);
+	return status;
+}
+
+void dlm_set_recover_status(struct dlm_ls *ls, uint32_t status)
+{
+	spin_lock(&ls->ls_recover_lock);
+	ls->ls_recover_status |= status;
+	spin_unlock(&ls->ls_recover_lock);
+}
+
+static int wait_status_all(struct dlm_ls *ls, uint32_t wait_status)
+{
+	struct dlm_rcom *rc = (struct dlm_rcom *) ls->ls_recover_buf;
+	struct dlm_member *memb;
+	int error = 0, delay;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		delay = 0;
+		for (;;) {
+			if (dlm_recovery_stopped(ls)) {
+				error = -EINTR;
+				goto out;
+			}
+
+			error = dlm_rcom_status(ls, memb->nodeid);
+			if (error)
+				goto out;
+
+			if (rc->rc_result & wait_status)
+				break;
+			if (delay < 1000)
+				delay += 20;
+			msleep(delay);
+		}
+	}
+ out:
+	return error;
+}
+
+static int wait_status_low(struct dlm_ls *ls, uint32_t wait_status)
+{
+	struct dlm_rcom *rc = (struct dlm_rcom *) ls->ls_recover_buf;
+	int error = 0, delay = 0, nodeid = ls->ls_low_nodeid;
+
+	for (;;) {
+		if (dlm_recovery_stopped(ls)) {
+			error = -EINTR;
+			goto out;
+		}
+
+		error = dlm_rcom_status(ls, nodeid);
+		if (error)
+			break;
+
+		if (rc->rc_result & wait_status)
+			break;
+		if (delay < 1000)
+			delay += 20;
+		msleep(delay);
+	}
+ out:
+	return error;
+}
+
+static int wait_status(struct dlm_ls *ls, uint32_t status)
+{
+	uint32_t status_all = status << 1;
+	int error;
+
+	if (ls->ls_low_nodeid == dlm_our_nodeid()) {
+		error = wait_status_all(ls, status);
+		if (!error)
+			dlm_set_recover_status(ls, status_all);
+	} else
+		error = wait_status_low(ls, status_all);
+
+	return error;
+}
+
+int dlm_recover_members_wait(struct dlm_ls *ls)
+{
+	return wait_status(ls, DLM_RS_NODES);
+}
+
+int dlm_recover_directory_wait(struct dlm_ls *ls)
+{
+	return wait_status(ls, DLM_RS_DIR);
+}
+
+int dlm_recover_locks_wait(struct dlm_ls *ls)
+{
+	return wait_status(ls, DLM_RS_LOCKS);
+}
+
+int dlm_recover_done_wait(struct dlm_ls *ls)
+{
+	return wait_status(ls, DLM_RS_DONE);
+}
+
+/*
+ * The recover_list contains all the rsb's for which we've requested the new
+ * master nodeid.  As replies are returned from the resource directories the
+ * rsb's are removed from the list.  When the list is empty we're done.
+ *
+ * The recover_list is later similarly used for all rsb's for which we've sent
+ * new lkb's and need to receive new corresponding lkid's.
+ *
+ * We use the address of the rsb struct as a simple local identifier for the
+ * rsb so we can match an rcom reply with the rsb it was sent for.
+ */
+
+static int recover_list_empty(struct dlm_ls *ls)
+{
+	int empty;
+
+	spin_lock(&ls->ls_recover_list_lock);
+	empty = list_empty(&ls->ls_recover_list);
+	spin_unlock(&ls->ls_recover_list_lock);
+
+	return empty;
+}
+
+static void recover_list_add(struct dlm_rsb *r)
+{
+	struct dlm_ls *ls = r->res_ls;
+
+	spin_lock(&ls->ls_recover_list_lock);
+	if (list_empty(&r->res_recover_list)) {
+		list_add_tail(&r->res_recover_list, &ls->ls_recover_list);
+		ls->ls_recover_list_count++;
+		dlm_hold_rsb(r);
+	}
+	spin_unlock(&ls->ls_recover_list_lock);
+}
+
+static void recover_list_del(struct dlm_rsb *r)
+{
+	struct dlm_ls *ls = r->res_ls;
+
+	spin_lock(&ls->ls_recover_list_lock);
+	list_del_init(&r->res_recover_list);
+	ls->ls_recover_list_count--;
+	spin_unlock(&ls->ls_recover_list_lock);
+
+	dlm_put_rsb(r);
+}
+
+static struct dlm_rsb *recover_list_find(struct dlm_ls *ls, uint64_t id)
+{
+	struct dlm_rsb *r = NULL;
+
+	spin_lock(&ls->ls_recover_list_lock);
+
+	list_for_each_entry(r, &ls->ls_recover_list, res_recover_list) {
+		if (id == (unsigned long) r)
+			goto out;
+	}
+	r = NULL;
+ out:
+	spin_unlock(&ls->ls_recover_list_lock);
+	return r;
+}
+
+static void recover_list_clear(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r, *s;
+
+	spin_lock(&ls->ls_recover_list_lock);
+	list_for_each_entry_safe(r, s, &ls->ls_recover_list, res_recover_list) {
+		list_del_init(&r->res_recover_list);
+		dlm_put_rsb(r);
+		ls->ls_recover_list_count--;
+	}
+
+	if (ls->ls_recover_list_count != 0) {
+		log_error(ls, "warning: recover_list_count %d",
+			  ls->ls_recover_list_count);
+		ls->ls_recover_list_count = 0;
+	}
+	spin_unlock(&ls->ls_recover_list_lock);
+}
+
+
+/* Master recovery: find new master node for rsb's that were
+   mastered on nodes that have been removed.
+
+   dlm_recover_masters
+   recover_master
+   dlm_send_rcom_lookup            ->  receive_rcom_lookup
+                                       dlm_dir_lookup
+   receive_rcom_lookup_reply       <-
+   dlm_recover_master_reply
+   set_new_master
+   set_master_lkbs
+   set_lock_master
+*/
+
+/*
+ * Set the lock master for all LKBs in a lock queue
+ * If we are the new master of the rsb, we may have received new
+ * MSTCPY locks from other nodes already which we need to ignore
+ * when setting the new nodeid.
+ */
+
+static void set_lock_master(struct list_head *queue, int nodeid)
+{
+	struct dlm_lkb *lkb;
+
+	list_for_each_entry(lkb, queue, lkb_statequeue)
+		if (!(lkb->lkb_flags & DLM_IFL_MSTCPY))
+			lkb->lkb_nodeid = nodeid;
+}
+
+static void set_master_lkbs(struct dlm_rsb *r)
+{
+	set_lock_master(&r->res_grantqueue, r->res_nodeid);
+	set_lock_master(&r->res_convertqueue, r->res_nodeid);
+	set_lock_master(&r->res_waitqueue, r->res_nodeid);
+}
+
+/*
+ * Propogate the new master nodeid to locks
+ * The NEW_MASTER flag tells dlm_recover_locks() which rsb's to consider.
+ * The NEW_MASTER2 flag tells recover_lvb() which rsb's to consider.
+ */
+
+static void set_new_master(struct dlm_rsb *r, int nodeid)
+{
+	lock_rsb(r);
+	r->res_nodeid = nodeid;
+	set_master_lkbs(r);
+	rsb_set_flag(r, RSB_NEW_MASTER);
+	rsb_set_flag(r, RSB_NEW_MASTER2);
+	unlock_rsb(r);
+}
+
+/*
+ * We do async lookups on rsb's that need new masters.  The rsb's
+ * waiting for a lookup reply are kept on the recover_list.
+ */
+
+static int recover_master(struct dlm_rsb *r)
+{
+	struct dlm_ls *ls = r->res_ls;
+	int error, dir_nodeid, ret_nodeid, our_nodeid = dlm_our_nodeid();
+
+	dir_nodeid = dlm_dir_nodeid(r);
+
+	if (dir_nodeid == our_nodeid) {
+		error = dlm_dir_lookup(ls, our_nodeid, r->res_name,
+				       r->res_length, &ret_nodeid);
+		if (error)
+			log_error(ls, "recover dir lookup error %d", error);
+
+		if (ret_nodeid == our_nodeid)
+			ret_nodeid = 0;
+		set_new_master(r, ret_nodeid);
+	} else {
+		recover_list_add(r);
+		error = dlm_send_rcom_lookup(r, dir_nodeid);
+	}
+
+	return error;
+}
+
+/*
+ * When not using a directory, most resource names will hash to a new static
+ * master nodeid and the resource will need to be remastered.
+ */
+
+static int recover_master_static(struct dlm_rsb *r)
+{
+	int master = dlm_dir_nodeid(r);
+
+	if (master == dlm_our_nodeid())
+		master = 0;
+
+	if (r->res_nodeid != master) {
+		if (is_master(r))
+			dlm_purge_mstcpy_locks(r);
+		set_new_master(r, master);
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * Go through local root resources and for each rsb which has a master which
+ * has departed, get the new master nodeid from the directory.  The dir will
+ * assign mastery to the first node to look up the new master.  That means
+ * we'll discover in this lookup if we're the new master of any rsb's.
+ *
+ * We fire off all the dir lookup requests individually and asynchronously to
+ * the correct dir node.
+ */
+
+int dlm_recover_masters(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r;
+	int error = 0, count = 0;
+
+	log_debug(ls, "dlm_recover_masters");
+
+	down_read(&ls->ls_root_sem);
+	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
+		if (dlm_recovery_stopped(ls)) {
+			up_read(&ls->ls_root_sem);
+			error = -EINTR;
+			goto out;
+		}
+
+		if (dlm_no_directory(ls))
+			count += recover_master_static(r);
+		else if (!is_master(r) && dlm_is_removed(ls, r->res_nodeid)) {
+			recover_master(r);
+			count++;
+		}
+
+		schedule();
+	}
+	up_read(&ls->ls_root_sem);
+
+	log_debug(ls, "dlm_recover_masters %d resources", count);
+
+	error = dlm_wait_function(ls, &recover_list_empty);
+ out:
+	if (error)
+		recover_list_clear(ls);
+	return error;
+}
+
+int dlm_recover_master_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
+{
+	struct dlm_rsb *r;
+	int nodeid;
+
+	r = recover_list_find(ls, rc->rc_id);
+	if (!r) {
+		log_error(ls, "dlm_recover_master_reply no id %"PRIx64"",
+			  rc->rc_id);
+		goto out;
+	}
+
+	nodeid = rc->rc_result;
+	if (nodeid == dlm_our_nodeid())
+		nodeid = 0;
+
+	set_new_master(r, nodeid);
+	recover_list_del(r);
+
+	if (recover_list_empty(ls))
+		wake_up(&ls->ls_wait_general);
+ out:
+	return 0;
+}
+
+
+/* Lock recovery: rebuild the process-copy locks we hold on a
+   remastered rsb on the new rsb master.
+
+   dlm_recover_locks
+   recover_locks
+   recover_locks_queue
+   dlm_send_rcom_lock              ->  receive_rcom_lock
+                                       dlm_recover_master_copy
+   receive_rcom_lock_reply         <-
+   dlm_recover_process_copy
+*/
+
+
+/*
+ * keep a count of the number of lkb's we send to the new master; when we get
+ * an equal number of replies then recovery for the rsb is done
+ */
+
+static int recover_locks_queue(struct dlm_rsb *r, struct list_head *head)
+{
+	struct dlm_lkb *lkb;
+	int error = 0;
+
+	list_for_each_entry(lkb, head, lkb_statequeue) {
+	   	error = dlm_send_rcom_lock(r, lkb);
+		if (error)
+			break;
+		r->res_recover_locks_count++;
+	}
+
+	return error;
+}
+
+static int all_queues_empty(struct dlm_rsb *r)
+{
+	if (!list_empty(&r->res_grantqueue) ||
+	    !list_empty(&r->res_convertqueue) ||
+	    !list_empty(&r->res_waitqueue))
+		return FALSE;
+	return TRUE;
+}
+
+static int recover_locks(struct dlm_rsb *r)
+{
+	int error = 0;
+
+	lock_rsb(r);
+	if (all_queues_empty(r))
+		goto out;
+
+	DLM_ASSERT(!r->res_recover_locks_count, dlm_print_rsb(r););
+
+	error = recover_locks_queue(r, &r->res_grantqueue);
+	if (error)
+		goto out;
+	error = recover_locks_queue(r, &r->res_convertqueue);
+	if (error)
+		goto out;
+	error = recover_locks_queue(r, &r->res_waitqueue);
+	if (error)
+		goto out;
+
+	if (r->res_recover_locks_count)
+		recover_list_add(r);
+	else
+		rsb_clear_flag(r, RSB_NEW_MASTER);
+ out:
+	unlock_rsb(r);
+	return error;
+}
+
+int dlm_recover_locks(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r;
+	int error, count = 0;
+
+	log_debug(ls, "dlm_recover_locks");
+
+	down_read(&ls->ls_root_sem);
+	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
+		if (is_master(r)) {
+			rsb_clear_flag(r, RSB_NEW_MASTER);
+			continue;
+		}
+
+		if (!rsb_flag(r, RSB_NEW_MASTER))
+			continue;
+
+		if (dlm_recovery_stopped(ls)) {
+			error = -EINTR;
+			up_read(&ls->ls_root_sem);
+			goto out;
+		}
+
+		error = recover_locks(r);
+		if (error) {
+			up_read(&ls->ls_root_sem);
+			goto out;
+		}
+
+		count += r->res_recover_locks_count;
+	}
+	up_read(&ls->ls_root_sem);
+
+	log_debug(ls, "dlm_recover_locks %d locks", count);
+
+	error = dlm_wait_function(ls, &recover_list_empty);
+ out:
+	if (error)
+		recover_list_clear(ls);
+	else
+		dlm_set_recover_status(ls, DLM_RS_LOCKS);
+	return error;
+}
+
+void dlm_recovered_lock(struct dlm_rsb *r)
+{
+	DLM_ASSERT(rsb_flag(r, RSB_NEW_MASTER), dlm_print_rsb(r););
+
+	r->res_recover_locks_count--;
+	if (!r->res_recover_locks_count) {
+		rsb_clear_flag(r, RSB_NEW_MASTER);
+		recover_list_del(r);
+	}
+
+	if (recover_list_empty(r->res_ls))
+		wake_up(&r->res_ls->ls_wait_general);
+}
+
+/*
+ * The lvb needs to be recovered on all master rsb's.  This includes setting
+ * the VALNOTVALID flag if necessary, and determining the correct lvb contents
+ * based on the lvb's of the locks held on the rsb.
+ *
+ * RSB_VALNOTVALID is set if there are only NL/CR locks on the rsb.  If it
+ * was already set prior to recovery, it's not cleared, regardless of locks.
+ *
+ * The LVB contents are only considered for changing when this is a new master
+ * of the rsb (NEW_MASTER2).  Then, the rsb's lvb is taken from any lkb with
+ * mode > CR.  If no lkb's exist with mode above CR, the lvb contents are taken
+ * from the lkb with the largest lvb sequence number.
+ */
+
+static void recover_lvb(struct dlm_rsb *r)
+{
+	struct dlm_lkb *lkb, *high_lkb = NULL;
+	uint32_t high_seq = 0;
+	int lock_lvb_exists = FALSE;
+	int big_lock_exists = FALSE;
+	int lvblen = r->res_ls->ls_lvblen;
+
+	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
+		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
+			continue;
+
+		lock_lvb_exists = TRUE;
+
+		if (lkb->lkb_grmode > DLM_LOCK_CR) {
+			big_lock_exists = TRUE;
+			goto setflag;
+		}
+
+		if (((int)lkb->lkb_lvbseq - (int)high_seq) >= 0) {
+			high_lkb = lkb;
+			high_seq = lkb->lkb_lvbseq;
+		}
+	}
+
+	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
+		if (!(lkb->lkb_exflags & DLM_LKF_VALBLK))
+			continue;
+
+		lock_lvb_exists = TRUE;
+
+		if (lkb->lkb_grmode > DLM_LOCK_CR) {
+			big_lock_exists = TRUE;
+			goto setflag;
+		}
+
+		if (((int)lkb->lkb_lvbseq - (int)high_seq) >= 0) {
+			high_lkb = lkb;
+			high_seq = lkb->lkb_lvbseq;
+		}
+	}
+
+ setflag:
+	if (!lock_lvb_exists)
+		goto out;
+
+	if (!big_lock_exists)
+		rsb_set_flag(r, RSB_VALNOTVALID);
+
+	/* don't mess with the lvb unless we're the new master */
+	if (!rsb_flag(r, RSB_NEW_MASTER2))
+		goto out;
+
+	if (!r->res_lvbptr) {
+		r->res_lvbptr = allocate_lvb(r->res_ls);
+		if (!r->res_lvbptr)
+			goto out;
+	}
+
+	if (big_lock_exists) {
+		r->res_lvbseq = lkb->lkb_lvbseq;
+		memcpy(r->res_lvbptr, lkb->lkb_lvbptr, lvblen);
+	} else if (high_lkb) {
+		r->res_lvbseq = high_lkb->lkb_lvbseq;
+		memcpy(r->res_lvbptr, high_lkb->lkb_lvbptr, lvblen);
+	} else {
+		r->res_lvbseq = 0;
+		memset(r->res_lvbptr, 0, lvblen);
+	}
+ out:
+	return;
+}
+
+/* All master rsb's flagged RECOVER_CONVERT need to be looked at.  The locks
+   converting PR->CW or CW->PR need to have their lkb_grmode set. */
+
+static void recover_conversion(struct dlm_rsb *r)
+{
+	struct dlm_lkb *lkb;
+	int grmode = -1;
+
+	list_for_each_entry(lkb, &r->res_grantqueue, lkb_statequeue) {
+		if (lkb->lkb_grmode == DLM_LOCK_PR ||
+		    lkb->lkb_grmode == DLM_LOCK_CW) {
+			grmode = lkb->lkb_grmode;
+			break;
+		}
+	}
+
+	list_for_each_entry(lkb, &r->res_convertqueue, lkb_statequeue) {
+		if (lkb->lkb_grmode != DLM_LOCK_IV)
+			continue;
+		if (grmode == -1)
+			lkb->lkb_grmode = lkb->lkb_rqmode;
+		else
+			lkb->lkb_grmode = grmode;
+	}
+}
+
+void dlm_recover_rsbs(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r;
+	int count = 0;
+
+	log_debug(ls, "dlm_recover_rsbs");
+
+	down_read(&ls->ls_root_sem);
+	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
+		lock_rsb(r);
+		if (is_master(r)) {
+			if (rsb_flag(r, RSB_RECOVER_CONVERT))
+				recover_conversion(r);
+			recover_lvb(r);
+			count++;
+		}
+		rsb_clear_flag(r, RSB_RECOVER_CONVERT);
+		unlock_rsb(r);
+	}
+	up_read(&ls->ls_root_sem);
+
+	log_debug(ls, "dlm_recover_rsbs %d rsbs", count);
+}
+
+/* Create a single list of all root rsb's to be used during recovery */
+
+int dlm_create_root_list(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r;
+	int i, error = 0;
+
+	down_write(&ls->ls_root_sem);
+	if (!list_empty(&ls->ls_root_list)) {
+		log_error(ls, "root list not empty");
+		error = -EINVAL;
+		goto out;
+	}
+
+	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
+		read_lock(&ls->ls_rsbtbl[i].lock);
+		list_for_each_entry(r, &ls->ls_rsbtbl[i].list, res_hashchain) {
+			list_add(&r->res_root_list, &ls->ls_root_list);
+			dlm_hold_rsb(r);
+		}
+		read_unlock(&ls->ls_rsbtbl[i].lock);
+	}
+ out:
+	up_write(&ls->ls_root_sem);
+	return error;
+}
+
+void dlm_release_root_list(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r, *safe;
+
+	down_write(&ls->ls_root_sem);
+	list_for_each_entry_safe(r, safe, &ls->ls_root_list, res_root_list) {
+		list_del_init(&r->res_root_list);
+		dlm_put_rsb(r);
+	}
+	up_write(&ls->ls_root_sem);
+}
+
+void dlm_clear_toss_list(struct dlm_ls *ls)
+{
+	struct dlm_rsb *r, *safe;
+	int i;
+
+	for (i = 0; i < ls->ls_rsbtbl_size; i++) {
+		write_lock(&ls->ls_rsbtbl[i].lock);
+		list_for_each_entry_safe(r, safe, &ls->ls_rsbtbl[i].toss,
+					 res_hashchain) {
+			list_del(&r->res_hashchain);
+			free_rsb(r);
+		}
+		write_unlock(&ls->ls_rsbtbl[i].lock);
+	}
+}
+

fs/dlm/recover.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __RECOVER_DOT_H__
+#define __RECOVER_DOT_H__
+
+int dlm_wait_function(struct dlm_ls *ls, int (*testfn) (struct dlm_ls *ls));
+uint32_t dlm_recover_status(struct dlm_ls *ls);
+void dlm_set_recover_status(struct dlm_ls *ls, uint32_t status);
+int dlm_recover_members_wait(struct dlm_ls *ls);
+int dlm_recover_directory_wait(struct dlm_ls *ls);
+int dlm_recover_locks_wait(struct dlm_ls *ls);
+int dlm_recover_done_wait(struct dlm_ls *ls);
+int dlm_recover_masters(struct dlm_ls *ls);
+int dlm_recover_master_reply(struct dlm_ls *ls, struct dlm_rcom *rc);
+int dlm_recover_locks(struct dlm_ls *ls);
+void dlm_recovered_lock(struct dlm_rsb *r);
+int dlm_create_root_list(struct dlm_ls *ls);
+void dlm_release_root_list(struct dlm_ls *ls);
+void dlm_clear_toss_list(struct dlm_ls *ls);
+void dlm_recover_rsbs(struct dlm_ls *ls);
+
+#endif				/* __RECOVER_DOT_H__ */
+

fs/dlm/recoverd.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "dir.h"
+#include "ast.h"
+#include "recover.h"
+#include "lowcomms.h"
+#include "lock.h"
+#include "requestqueue.h"
+#include "recoverd.h"
+
+
+/* If the start for which we're re-enabling locking (seq) has been superseded
+   by a newer stop (ls_recover_seq), we need to leave locking disabled. */
+
+static int enable_locking(struct dlm_ls *ls, uint64_t seq)
+{
+	int error = -EINTR;
+
+	spin_lock(&ls->ls_recover_lock);
+	if (ls->ls_recover_seq == seq) {
+		set_bit(LSFL_RUNNING, &ls->ls_flags);
+		up_write(&ls->ls_in_recovery);
+		error = 0;
+	}
+	spin_unlock(&ls->ls_recover_lock);
+	return error;
+}
+
+static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
+{
+	unsigned long start;
+	int error, neg = 0;
+
+	log_debug(ls, "recover %"PRIx64"", rv->seq);
+
+	down(&ls->ls_recoverd_active);
+
+	/*
+	 * Suspending and resuming dlm_astd ensures that no lkb's from this ls
+	 * will be processed by dlm_astd during recovery.
+	 */
+
+	dlm_astd_suspend();
+	dlm_astd_resume();
+
+	/*
+	 * This list of root rsb's will be the basis of most of the recovery
+	 * routines.
+	 */
+
+	dlm_create_root_list(ls);
+
+	/*
+	 * Free all the tossed rsb's so we don't have to recover them.
+	 */
+
+	dlm_clear_toss_list(ls);
+
+	/*
+	 * Add or remove nodes from the lockspace's ls_nodes list.
+	 * Also waits for all nodes to complete dlm_recover_members.
+	 */
+
+	error = dlm_recover_members(ls, rv, &neg);
+	if (error) {
+		log_error(ls, "recover_members failed %d", error);
+		goto fail;
+	}
+	start = jiffies;
+
+	/*
+	 * Rebuild our own share of the directory by collecting from all other
+	 * nodes their master rsb names that hash to us.
+	 */
+
+	error = dlm_recover_directory(ls);
+	if (error) {
+		log_error(ls, "recover_directory failed %d", error);
+		goto fail;
+	}
+
+	/*
+	 * Purge directory-related requests that are saved in requestqueue.
+	 * All dir requests from before recovery are invalid now due to the dir
+	 * rebuild and will be resent by the requesting nodes.
+	 */
+
+	dlm_purge_requestqueue(ls);
+
+	/*
+	 * Wait for all nodes to complete directory rebuild.
+	 */
+
+	error = dlm_recover_directory_wait(ls);
+	if (error) {
+		log_error(ls, "recover_directory_wait failed %d", error);
+		goto fail;
+	}
+
+	/*
+	 * We may have outstanding operations that are waiting for a reply from
+	 * a failed node.  Mark these to be resent after recovery.  Unlock and
+	 * cancel ops can just be completed.
+	 */
+
+	dlm_recover_waiters_pre(ls);
+
+	error = dlm_recovery_stopped(ls);
+	if (error)
+		goto fail;
+
+	if (neg || dlm_no_directory(ls)) {
+		/*
+		 * Clear lkb's for departed nodes.
+		 */
+
+		dlm_purge_locks(ls);
+
+		/*
+		 * Get new master nodeid's for rsb's that were mastered on
+		 * departed nodes.
+		 */
+
+		error = dlm_recover_masters(ls);
+		if (error) {
+			log_error(ls, "recover_masters failed %d", error);
+			goto fail;
+		}
+
+		/*
+		 * Send our locks on remastered rsb's to the new masters.
+		 */
+
+		error = dlm_recover_locks(ls);
+		if (error) {
+			log_error(ls, "recover_locks failed %d", error);
+			goto fail;
+		}
+
+		error = dlm_recover_locks_wait(ls);
+		if (error) {
+			log_error(ls, "recover_locks_wait failed %d", error);
+			goto fail;
+		}
+
+		/*
+		 * Finalize state in master rsb's now that all locks can be
+		 * checked.  This includes conversion resolution and lvb
+		 * settings.
+		 */
+
+		dlm_recover_rsbs(ls);
+	}
+
+	dlm_release_root_list(ls);
+
+	dlm_set_recover_status(ls, DLM_RS_DONE);
+	error = dlm_recover_done_wait(ls);
+	if (error) {
+		log_error(ls, "recover_done_wait failed %d", error);
+		goto fail;
+	}
+
+	dlm_clear_members_gone(ls);
+
+	error = enable_locking(ls, rv->seq);
+	if (error) {
+		log_error(ls, "enable_locking failed %d", error);
+		goto fail;
+	}
+
+	error = dlm_process_requestqueue(ls);
+	if (error) {
+		log_error(ls, "process_requestqueue failed %d", error);
+		goto fail;
+	}
+
+	error = dlm_recover_waiters_post(ls);
+	if (error) {
+		log_error(ls, "recover_waiters_post failed %d", error);
+		goto fail;
+	}
+
+	dlm_grant_after_purge(ls);
+
+	dlm_astd_wake();
+
+	log_debug(ls, "recover %"PRIx64" done: %u ms", rv->seq,
+		  jiffies_to_msecs(jiffies - start));
+	up(&ls->ls_recoverd_active);
+
+	return 0;
+
+ fail:
+	dlm_release_root_list(ls);
+	log_debug(ls, "recover %"PRIx64" error %d", rv->seq, error);
+	up(&ls->ls_recoverd_active);
+	return error;
+}
+
+static void do_ls_recovery(struct dlm_ls *ls)
+{
+	struct dlm_recover *rv = NULL;
+
+	spin_lock(&ls->ls_recover_lock);
+	rv = ls->ls_recover_args;
+	ls->ls_recover_args = NULL;
+	clear_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
+	spin_unlock(&ls->ls_recover_lock);
+
+	if (rv) {
+		ls_recover(ls, rv);
+		kfree(rv->nodeids);
+		kfree(rv);
+	}
+}
+
+static int dlm_recoverd(void *arg)
+{
+	struct dlm_ls *ls;
+
+	ls = dlm_find_lockspace_local(arg);
+
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (!test_bit(LSFL_WORK, &ls->ls_flags))
+			schedule();
+		set_current_state(TASK_RUNNING);
+
+		if (test_and_clear_bit(LSFL_WORK, &ls->ls_flags))
+			do_ls_recovery(ls);
+	}
+
+	dlm_put_lockspace(ls);
+	return 0;
+}
+
+void dlm_recoverd_kick(struct dlm_ls *ls)
+{
+	set_bit(LSFL_WORK, &ls->ls_flags);
+	wake_up_process(ls->ls_recoverd_task);
+}
+
+int dlm_recoverd_start(struct dlm_ls *ls)
+{
+	struct task_struct *p;
+	int error = 0;
+
+	p = kthread_run(dlm_recoverd, ls, "dlm_recoverd");
+	if (IS_ERR(p))
+		error = PTR_ERR(p);
+	else
+                ls->ls_recoverd_task = p;
+	return error;
+}
+
+void dlm_recoverd_stop(struct dlm_ls *ls)
+{
+	kthread_stop(ls->ls_recoverd_task);
+}
+
+void dlm_recoverd_suspend(struct dlm_ls *ls)
+{
+	down(&ls->ls_recoverd_active);
+}
+
+void dlm_recoverd_resume(struct dlm_ls *ls)
+{
+	up(&ls->ls_recoverd_active);
+}
+

fs/dlm/recoverd.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __RECOVERD_DOT_H__
+#define __RECOVERD_DOT_H__
+
+void dlm_recoverd_kick(struct dlm_ls *ls);
+void dlm_recoverd_stop(struct dlm_ls *ls);
+int dlm_recoverd_start(struct dlm_ls *ls);
+void dlm_recoverd_suspend(struct dlm_ls *ls);
+void dlm_recoverd_resume(struct dlm_ls *ls);
+
+#endif				/* __RECOVERD_DOT_H__ */
+

fs/dlm/requestqueue.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "member.h"
+#include "lock.h"
+#include "dir.h"
+#include "config.h"
+#include "requestqueue.h"
+
+struct rq_entry {
+	struct list_head list;
+	int nodeid;
+	char request[1];
+};
+
+/*
+ * Requests received while the lockspace is in recovery get added to the
+ * request queue and processed when recovery is complete.  This happens when
+ * the lockspace is suspended on some nodes before it is on others, or the
+ * lockspace is enabled on some while still suspended on others.
+ */
+
+void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd)
+{
+	struct rq_entry *e;
+	int length = hd->h_length;
+
+	if (dlm_is_removed(ls, nodeid))
+		return;
+
+	e = kmalloc(sizeof(struct rq_entry) + length, GFP_KERNEL);
+	if (!e) {
+		log_print("dlm_add_requestqueue: out of memory\n");
+		return;
+	}
+
+	e->nodeid = nodeid;
+	memcpy(e->request, hd, length);
+
+	down(&ls->ls_requestqueue_lock);
+	list_add_tail(&e->list, &ls->ls_requestqueue);
+	up(&ls->ls_requestqueue_lock);
+}
+
+int dlm_process_requestqueue(struct dlm_ls *ls)
+{
+	struct rq_entry *e;
+	struct dlm_header *hd;
+	int error = 0;
+
+	down(&ls->ls_requestqueue_lock);
+
+	for (;;) {
+		if (list_empty(&ls->ls_requestqueue)) {
+			up(&ls->ls_requestqueue_lock);
+			error = 0;
+			break;
+		}
+		e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
+		up(&ls->ls_requestqueue_lock);
+
+		hd = (struct dlm_header *) e->request;
+		error = dlm_receive_message(hd, e->nodeid, TRUE);
+
+		if (error == -EINTR) {
+			/* entry is left on requestqueue */
+			log_debug(ls, "process_requestqueue abort eintr");
+			break;
+		}
+
+		down(&ls->ls_requestqueue_lock);
+		list_del(&e->list);
+		kfree(e);
+
+		if (dlm_locking_stopped(ls)) {
+			log_debug(ls, "process_requestqueue abort running");
+			up(&ls->ls_requestqueue_lock);
+			error = -EINTR;
+			break;
+		}
+		schedule();
+	}
+
+	return error;
+}
+
+/*
+ * After recovery is done, locking is resumed and dlm_recoverd takes all the
+ * saved requests and processes them as they would have been by dlm_recvd.  At
+ * the same time, dlm_recvd will start receiving new requests from remote
+ * nodes.  We want to delay dlm_recvd processing new requests until
+ * dlm_recoverd has finished processing the old saved requests.
+ */
+
+void dlm_wait_requestqueue(struct dlm_ls *ls)
+{
+	for (;;) {
+		down(&ls->ls_requestqueue_lock);
+		if (list_empty(&ls->ls_requestqueue))
+			break;
+		if (dlm_locking_stopped(ls))
+			break;
+		up(&ls->ls_requestqueue_lock);
+		schedule();
+	}
+	up(&ls->ls_requestqueue_lock);
+}
+
+static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
+{
+	uint32_t type = ms->m_type;
+
+	if (dlm_is_removed(ls, nodeid))
+		return 1;
+
+	/* directory operations are always purged because the directory is
+	   always rebuilt during recovery and the lookups resent */
+
+	if (type == DLM_MSG_REMOVE ||
+	    type == DLM_MSG_LOOKUP ||
+	    type == DLM_MSG_LOOKUP_REPLY)
+		return 1;
+
+	if (!dlm_no_directory(ls))
+		return 0;
+
+	/* with no directory, the master is likely to change as a part of
+	   recovery; requests to/from the defunct master need to be purged */
+
+	switch (type) {
+	case DLM_MSG_REQUEST:
+	case DLM_MSG_CONVERT:
+	case DLM_MSG_UNLOCK:
+	case DLM_MSG_CANCEL:
+		/* we're no longer the master of this resource, the sender
+		   will resend to the new master (see waiter_needs_recovery) */
+
+		if (dlm_hash2nodeid(ls, ms->m_hash) != dlm_our_nodeid())
+			return 1;
+		break;
+
+	case DLM_MSG_REQUEST_REPLY:
+	case DLM_MSG_CONVERT_REPLY:
+	case DLM_MSG_UNLOCK_REPLY:
+	case DLM_MSG_CANCEL_REPLY:
+	case DLM_MSG_GRANT:
+		/* this reply is from the former master of the resource,
+		   we'll resend to the new master if needed */
+
+		if (dlm_hash2nodeid(ls, ms->m_hash) != nodeid)
+			return 1;
+		break;
+	}
+
+	return 0;
+}
+
+void dlm_purge_requestqueue(struct dlm_ls *ls)
+{
+	struct dlm_message *ms;
+	struct rq_entry *e, *safe;
+
+	down(&ls->ls_requestqueue_lock);
+	list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
+		ms = (struct dlm_message *) e->request;
+
+		if (purge_request(ls, ms, e->nodeid)) {
+			list_del(&e->list);
+			kfree(e);
+		}
+	}
+	up(&ls->ls_requestqueue_lock);
+}
+

fs/dlm/requestqueue.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __REQUESTQUEUE_DOT_H__
+#define __REQUESTQUEUE_DOT_H__
+
+void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd);
+int dlm_process_requestqueue(struct dlm_ls *ls);
+void dlm_wait_requestqueue(struct dlm_ls *ls);
+void dlm_purge_requestqueue(struct dlm_ls *ls);
+
+#endif
+

fs/dlm/util.c

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "dlm_internal.h"
+#include "rcom.h"
+#include "util.h"
+
+static void header_out(struct dlm_header *hd)
+{
+	hd->h_version		= cpu_to_le32(hd->h_version);
+	hd->h_lockspace		= cpu_to_le32(hd->h_lockspace);
+	hd->h_nodeid		= cpu_to_le32(hd->h_nodeid);
+	hd->h_length		= cpu_to_le16(hd->h_length);
+}
+
+static void header_in(struct dlm_header *hd)
+{
+	hd->h_version		= le32_to_cpu(hd->h_version);
+	hd->h_lockspace		= le32_to_cpu(hd->h_lockspace);
+	hd->h_nodeid		= le32_to_cpu(hd->h_nodeid);
+	hd->h_length		= le16_to_cpu(hd->h_length);
+}
+
+void dlm_message_out(struct dlm_message *ms)
+{
+	struct dlm_header *hd = (struct dlm_header *) ms;
+
+	header_out(hd);
+
+	ms->m_type		= cpu_to_le32(ms->m_type);
+	ms->m_nodeid		= cpu_to_le32(ms->m_nodeid);
+	ms->m_pid		= cpu_to_le32(ms->m_pid);
+	ms->m_lkid		= cpu_to_le32(ms->m_lkid);
+	ms->m_remid		= cpu_to_le32(ms->m_remid);
+	ms->m_parent_lkid	= cpu_to_le32(ms->m_parent_lkid);
+	ms->m_parent_remid	= cpu_to_le32(ms->m_parent_remid);
+	ms->m_exflags		= cpu_to_le32(ms->m_exflags);
+	ms->m_sbflags		= cpu_to_le32(ms->m_sbflags);
+	ms->m_flags		= cpu_to_le32(ms->m_flags);
+	ms->m_lvbseq		= cpu_to_le32(ms->m_lvbseq);
+	ms->m_hash		= cpu_to_le32(ms->m_hash);
+	ms->m_status		= cpu_to_le32(ms->m_status);
+	ms->m_grmode		= cpu_to_le32(ms->m_grmode);
+	ms->m_rqmode		= cpu_to_le32(ms->m_rqmode);
+	ms->m_bastmode		= cpu_to_le32(ms->m_bastmode);
+	ms->m_asts		= cpu_to_le32(ms->m_asts);
+	ms->m_result		= cpu_to_le32(ms->m_result);
+	ms->m_range[0]		= cpu_to_le64(ms->m_range[0]);
+	ms->m_range[1]		= cpu_to_le64(ms->m_range[1]);
+}
+
+void dlm_message_in(struct dlm_message *ms)
+{
+	struct dlm_header *hd = (struct dlm_header *) ms;
+
+	header_in(hd);
+
+	ms->m_type		= le32_to_cpu(ms->m_type);
+	ms->m_nodeid		= le32_to_cpu(ms->m_nodeid);
+	ms->m_pid		= le32_to_cpu(ms->m_pid);
+	ms->m_lkid		= le32_to_cpu(ms->m_lkid);
+	ms->m_remid		= le32_to_cpu(ms->m_remid);
+	ms->m_parent_lkid	= le32_to_cpu(ms->m_parent_lkid);
+	ms->m_parent_remid	= le32_to_cpu(ms->m_parent_remid);
+	ms->m_exflags		= le32_to_cpu(ms->m_exflags);
+	ms->m_sbflags		= le32_to_cpu(ms->m_sbflags);
+	ms->m_flags		= le32_to_cpu(ms->m_flags);
+	ms->m_lvbseq		= le32_to_cpu(ms->m_lvbseq);
+	ms->m_hash		= le32_to_cpu(ms->m_hash);
+	ms->m_status		= le32_to_cpu(ms->m_status);
+	ms->m_grmode		= le32_to_cpu(ms->m_grmode);
+	ms->m_rqmode		= le32_to_cpu(ms->m_rqmode);
+	ms->m_bastmode		= le32_to_cpu(ms->m_bastmode);
+	ms->m_asts		= le32_to_cpu(ms->m_asts);
+	ms->m_result		= le32_to_cpu(ms->m_result);
+	ms->m_range[0]		= le64_to_cpu(ms->m_range[0]);
+	ms->m_range[1]		= le64_to_cpu(ms->m_range[1]);
+}
+
+static void rcom_lock_out(struct rcom_lock *rl)
+{
+	rl->rl_ownpid		= cpu_to_le32(rl->rl_ownpid);
+	rl->rl_lkid		= cpu_to_le32(rl->rl_lkid);
+	rl->rl_remid		= cpu_to_le32(rl->rl_remid);
+	rl->rl_parent_lkid	= cpu_to_le32(rl->rl_parent_lkid);
+	rl->rl_parent_remid	= cpu_to_le32(rl->rl_parent_remid);
+	rl->rl_exflags		= cpu_to_le32(rl->rl_exflags);
+	rl->rl_flags		= cpu_to_le32(rl->rl_flags);
+	rl->rl_lvbseq		= cpu_to_le32(rl->rl_lvbseq);
+	rl->rl_result		= cpu_to_le32(rl->rl_result);
+	rl->rl_wait_type	= cpu_to_le16(rl->rl_wait_type);
+	rl->rl_namelen		= cpu_to_le16(rl->rl_namelen);
+	rl->rl_range[0]		= cpu_to_le64(rl->rl_range[0]);
+	rl->rl_range[1]		= cpu_to_le64(rl->rl_range[1]);
+	rl->rl_range[2]		= cpu_to_le64(rl->rl_range[2]);
+	rl->rl_range[3]		= cpu_to_le64(rl->rl_range[3]);
+}
+
+static void rcom_lock_in(struct rcom_lock *rl)
+{
+	rl->rl_ownpid		= le32_to_cpu(rl->rl_ownpid);
+	rl->rl_lkid		= le32_to_cpu(rl->rl_lkid);
+	rl->rl_remid		= le32_to_cpu(rl->rl_remid);
+	rl->rl_parent_lkid	= le32_to_cpu(rl->rl_parent_lkid);
+	rl->rl_parent_remid	= le32_to_cpu(rl->rl_parent_remid);
+	rl->rl_exflags		= le32_to_cpu(rl->rl_exflags);
+	rl->rl_flags		= le32_to_cpu(rl->rl_flags);
+	rl->rl_lvbseq		= le32_to_cpu(rl->rl_lvbseq);
+	rl->rl_result		= le32_to_cpu(rl->rl_result);
+	rl->rl_wait_type	= le16_to_cpu(rl->rl_wait_type);
+	rl->rl_namelen		= le16_to_cpu(rl->rl_namelen);
+	rl->rl_range[0]		= le64_to_cpu(rl->rl_range[0]);
+	rl->rl_range[1]		= le64_to_cpu(rl->rl_range[1]);
+	rl->rl_range[2]		= le64_to_cpu(rl->rl_range[2]);
+	rl->rl_range[3]		= le64_to_cpu(rl->rl_range[3]);
+}
+
+static void rcom_config_out(struct rcom_config *rf)
+{
+	rf->rf_lvblen		= cpu_to_le32(rf->rf_lvblen);
+	rf->rf_lsflags		= cpu_to_le32(rf->rf_lsflags);
+}
+
+static void rcom_config_in(struct rcom_config *rf)
+{
+	rf->rf_lvblen		= le32_to_cpu(rf->rf_lvblen);
+	rf->rf_lsflags		= le32_to_cpu(rf->rf_lsflags);
+}
+
+void dlm_rcom_out(struct dlm_rcom *rc)
+{
+	struct dlm_header *hd = (struct dlm_header *) rc;
+	int type = rc->rc_type;
+
+	header_out(hd);
+
+	rc->rc_type		= cpu_to_le32(rc->rc_type);
+	rc->rc_result		= cpu_to_le32(rc->rc_result);
+	rc->rc_id		= cpu_to_le64(rc->rc_id);
+
+	if (type == DLM_RCOM_LOCK)
+		rcom_lock_out((struct rcom_lock *) rc->rc_buf);
+
+	else if (type == DLM_RCOM_STATUS_REPLY)
+		rcom_config_out((struct rcom_config *) rc->rc_buf);
+}
+
+void dlm_rcom_in(struct dlm_rcom *rc)
+{
+	struct dlm_header *hd = (struct dlm_header *) rc;
+
+	header_in(hd);
+
+	rc->rc_type		= le32_to_cpu(rc->rc_type);
+	rc->rc_result		= le32_to_cpu(rc->rc_result);
+	rc->rc_id		= le64_to_cpu(rc->rc_id);
+
+	if (rc->rc_type == DLM_RCOM_LOCK)
+		rcom_lock_in((struct rcom_lock *) rc->rc_buf);
+
+	else if (rc->rc_type == DLM_RCOM_STATUS_REPLY)
+		rcom_config_in((struct rcom_config *) rc->rc_buf);
+}
+

fs/dlm/util.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __UTIL_DOT_H__
+#define __UTIL_DOT_H__
+
+void dlm_message_out(struct dlm_message *ms);
+void dlm_message_in(struct dlm_message *ms);
+void dlm_rcom_out(struct dlm_rcom *rc);
+void dlm_rcom_in(struct dlm_rcom *rc);
+
+#endif
+

include/linux/dlm.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#ifndef __DLM_DOT_H__
+#define __DLM_DOT_H__
+
+/*
+ * Interface to Distributed Lock Manager (DLM)
+ * routines and structures to use DLM lockspaces
+ */
+
+/*
+ * Lock Modes
+ */
+
+#define DLM_LOCK_IV		-1	/* invalid */
+#define DLM_LOCK_NL		0	/* null */
+#define DLM_LOCK_CR		1	/* concurrent read */
+#define DLM_LOCK_CW		2	/* concurrent write */
+#define DLM_LOCK_PR		3	/* protected read */
+#define DLM_LOCK_PW		4	/* protected write */
+#define DLM_LOCK_EX		5	/* exclusive */
+
+/*
+ * Maximum size in bytes of a dlm_lock name
+ */
+
+#define DLM_RESNAME_MAXLEN	64
+
+/*
+ * Flags to dlm_lock
+ *
+ * DLM_LKF_NOQUEUE
+ *
+ * Do not queue the lock request on the wait queue if it cannot be granted
+ * immediately.  If the lock cannot be granted because of this flag, DLM will
+ * either return -EAGAIN from the dlm_lock call or will return 0 from
+ * dlm_lock and -EAGAIN in the lock status block when the AST is executed.
+ *
+ * DLM_LKF_CANCEL
+ *
+ * Used to cancel a pending lock request or conversion.  A converting lock is
+ * returned to its previously granted mode.
+ *
+ * DLM_LKF_CONVERT
+ *
+ * Indicates a lock conversion request.  For conversions the name and namelen
+ * are ignored and the lock ID in the LKSB is used to identify the lock.
+ *
+ * DLM_LKF_VALBLK
+ *
+ * Requests DLM to return the current contents of the lock value block in the
+ * lock status block.  When this flag is set in a lock conversion from PW or EX
+ * modes, DLM assigns the value specified in the lock status block to the lock
+ * value block of the lock resource.  The LVB is a DLM_LVB_LEN size array
+ * containing application-specific information.
+ *
+ * DLM_LKF_QUECVT
+ *
+ * Force a conversion request to be queued, even if it is compatible with
+ * the granted modes of other locks on the same resource.
+ *
+ * DLM_LKF_IVVALBLK
+ *
+ * Invalidate the lock value block.
+ *
+ * DLM_LKF_CONVDEADLK
+ *
+ * Allows the dlm to resolve conversion deadlocks internally by demoting the
+ * granted mode of a converting lock to NL.  The DLM_SBF_DEMOTED flag is
+ * returned for a conversion that's been effected by this.
+ *
+ * DLM_LKF_PERSISTENT
+ *
+ * Only relevant to locks originating in userspace.  A persistent lock will not
+ * be removed if the process holding the lock exits.
+ *
+ * DLM_LKF_NODLKWT
+ * DLM_LKF_NODLCKBLK
+ *
+ * net yet implemented
+ *
+ * DLM_LKF_EXPEDITE
+ *
+ * Used only with new requests for NL mode locks.  Tells the lock manager
+ * to grant the lock, ignoring other locks in convert and wait queues.
+ *
+ * DLM_LKF_NOQUEUEBAST
+ *
+ * Send blocking AST's before returning -EAGAIN to the caller.  It is only
+ * used along with the NOQUEUE flag.  Blocking AST's are not sent for failed
+ * NOQUEUE requests otherwise.
+ *
+ * DLM_LKF_HEADQUE
+ *
+ * Add a lock to the head of the convert or wait queue rather than the tail.
+ *
+ * DLM_LKF_NOORDER
+ *
+ * Disregard the standard grant order rules and grant a lock as soon as it
+ * is compatible with other granted locks.
+ *
+ * DLM_LKF_ORPHAN
+ *
+ * not yet implemented
+ *
+ * DLM_LKF_ALTPR
+ *
+ * If the requested mode cannot be granted immediately, try to grant the lock
+ * in PR mode instead.  If this alternate mode is granted instead of the
+ * requested mode, DLM_SBF_ALTMODE is returned in the lksb.
+ *
+ * DLM_LKF_ALTCW
+ *
+ * The same as ALTPR, but the alternate mode is CW.
+ *
+ * DLM_LKF_FORCEUNLOCK
+ *
+ * Unlock the lock even if it is converting or waiting or has sublocks.
+ * Only really for use by the userland device.c code.
+ *
+ */
+
+#define DLM_LKF_NOQUEUE		0x00000001
+#define DLM_LKF_CANCEL		0x00000002
+#define DLM_LKF_CONVERT		0x00000004
+#define DLM_LKF_VALBLK		0x00000008
+#define DLM_LKF_QUECVT		0x00000010
+#define DLM_LKF_IVVALBLK	0x00000020
+#define DLM_LKF_CONVDEADLK	0x00000040
+#define DLM_LKF_PERSISTENT	0x00000080
+#define DLM_LKF_NODLCKWT	0x00000100
+#define DLM_LKF_NODLCKBLK	0x00000200
+#define DLM_LKF_EXPEDITE	0x00000400
+#define DLM_LKF_NOQUEUEBAST	0x00000800
+#define DLM_LKF_HEADQUE		0x00001000
+#define DLM_LKF_NOORDER		0x00002000
+#define DLM_LKF_ORPHAN		0x00004000
+#define DLM_LKF_ALTPR		0x00008000
+#define DLM_LKF_ALTCW		0x00010000
+#define DLM_LKF_FORCEUNLOCK	0x00020000
+
+/*
+ * Some return codes that are not in errno.h
+ */
+
+#define DLM_ECANCEL		0x10001
+#define DLM_EUNLOCK		0x10002
+
+typedef void dlm_lockspace_t;
+
+/*
+ * Lock range structure
+ */
+
+struct dlm_range {
+	uint64_t ra_start;
+	uint64_t ra_end;
+};
+
+/*
+ * Lock status block
+ *
+ * Use this structure to specify the contents of the lock value block.  For a
+ * conversion request, this structure is used to specify the lock ID of the
+ * lock.  DLM writes the status of the lock request and the lock ID assigned
+ * to the request in the lock status block.
+ *
+ * sb_lkid: the returned lock ID.  It is set on new (non-conversion) requests.
+ * It is available when dlm_lock returns.
+ *
+ * sb_lvbptr: saves or returns the contents of the lock's LVB according to rules
+ * shown for the DLM_LKF_VALBLK flag.
+ *
+ * sb_flags: DLM_SBF_DEMOTED is returned if in the process of promoting a lock,
+ * it was first demoted to NL to avoid conversion deadlock.
+ * DLM_SBF_VALNOTVALID is returned if the resource's LVB is marked invalid.
+ *
+ * sb_status: the returned status of the lock request set prior to AST
+ * execution.  Possible return values:
+ *
+ * 0 if lock request was successful
+ * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
+ * -ENOMEM if there is no memory to process request
+ * -EINVAL if there are invalid parameters
+ * -DLM_EUNLOCK if unlock request was successful
+ * -DLM_ECANCEL if a cancel completed successfully
+ */
+
+#define DLM_SBF_DEMOTED		0x01
+#define DLM_SBF_VALNOTVALID	0x02
+#define DLM_SBF_ALTMODE		0x04
+
+struct dlm_lksb {
+	int 	 sb_status;
+	uint32_t sb_lkid;
+	char 	 sb_flags;
+	char *	 sb_lvbptr;
+};
+
+
+#ifdef __KERNEL__
+
+#define DLM_LSFL_NODIR		0x00000001
+
+/*
+ * dlm_new_lockspace
+ *
+ * Starts a lockspace with the given name.  If the named lockspace exists in
+ * the cluster, the calling node joins it.
+ */
+
+int dlm_new_lockspace(char *name, int namelen, dlm_lockspace_t **lockspace,
+		      uint32_t flags, int lvblen);
+
+/*
+ * dlm_release_lockspace
+ *
+ * Stop a lockspace.
+ */
+
+int dlm_release_lockspace(dlm_lockspace_t *lockspace, int force);
+
+/*
+ * dlm_lock
+ *
+ * Make an asyncronous request to acquire or convert a lock on a named
+ * resource.
+ *
+ * lockspace: context for the request
+ * mode: the requested mode of the lock (DLM_LOCK_)
+ * lksb: lock status block for input and async return values
+ * flags: input flags (DLM_LKF_)
+ * name: name of the resource to lock, can be binary
+ * namelen: the length in bytes of the resource name (MAX_RESNAME_LEN)
+ * parent: the lock ID of a parent lock or 0 if none
+ * lockast: function DLM executes when it completes processing the request
+ * astarg: argument passed to lockast and bast functions
+ * bast: function DLM executes when this lock later blocks another request
+ *
+ * Returns:
+ * 0 if request is successfully queued for processing
+ * -EINVAL if any input parameters are invalid
+ * -EAGAIN if request would block and is flagged DLM_LKF_NOQUEUE
+ * -ENOMEM if there is no memory to process request
+ * -ENOTCONN if there is a communication error
+ *
+ * If the call to dlm_lock returns an error then the operation has failed and
+ * the AST routine will not be called.  If dlm_lock returns 0 it is still
+ * possible that the lock operation will fail. The AST routine will be called
+ * when the locking is complete and the status is returned in the lksb.
+ *
+ * If the AST routines or parameter are passed to a conversion operation then
+ * they will overwrite those values that were passed to a previous dlm_lock
+ * call.
+ *
+ * AST routines should not block (at least not for long), but may make
+ * any locking calls they please.
+ */
+
+int dlm_lock(dlm_lockspace_t *lockspace,
+	     int mode,
+	     struct dlm_lksb *lksb,
+	     uint32_t flags,
+	     void *name,
+	     unsigned int namelen,
+	     uint32_t parent_lkid,
+	     void (*lockast) (void *astarg),
+	     void *astarg,
+	     void (*bast) (void *astarg, int mode),
+	     struct dlm_range *range);
+
+/*
+ * dlm_unlock
+ *
+ * Asynchronously release a lock on a resource.  The AST routine is called
+ * when the resource is successfully unlocked.
+ *
+ * lockspace: context for the request
+ * lkid: the lock ID as returned in the lksb
+ * flags: input flags (DLM_LKF_)
+ * lksb: if NULL the lksb parameter passed to last lock request is used
+ * astarg: the arg used with the completion ast for the unlock
+ *
+ * Returns:
+ * 0 if request is successfully queued for processing
+ * -EINVAL if any input parameters are invalid
+ * -ENOTEMPTY if the lock still has sublocks
+ * -EBUSY if the lock is waiting for a remote lock operation
+ * -ENOTCONN if there is a communication error
+ */
+
+int dlm_unlock(dlm_lockspace_t *lockspace,
+	       uint32_t lkid,
+	       uint32_t flags,
+	       struct dlm_lksb *lksb,
+	       void *astarg);
+
+#endif				/* __KERNEL__ */
+
+#endif				/* __DLM_DOT_H__ */
+

include/linux/dlm_device.h

···
+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
+**
+**  This copyrighted material is made available to anyone wishing to use,
+**  modify, copy, or redistribute it subject to the terms and conditions
+**  of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+/* This is the device interface for dlm, most users will use a library
+ * interface.
+ */
+
+#define DLM_USER_LVB_LEN	32
+
+/* Version of the device interface */
+#define DLM_DEVICE_VERSION_MAJOR 3
+#define DLM_DEVICE_VERSION_MINOR 0
+#define DLM_DEVICE_VERSION_PATCH 0
+
+/* struct passed to the lock write */
+struct dlm_lock_params {
+	__u8 mode;
+	__u16 flags;
+	__u32 lkid;
+	__u32 parent;
+	struct dlm_range range;
+	__u8 namelen;
+        void __user *castparam;
+	void __user *castaddr;
+	void __user *bastparam;
+        void __user *bastaddr;
+	struct dlm_lksb __user *lksb;
+	char lvb[DLM_USER_LVB_LEN];
+	char name[1];
+};
+
+struct dlm_lspace_params {
+	__u32 flags;
+	__u32 minor;
+	char name[1];
+};
+
+struct dlm_write_request {
+	__u32 version[3];
+	__u8 cmd;
+
+	union  {
+		struct dlm_lock_params   lock;
+		struct dlm_lspace_params lspace;
+	} i;
+};
+
+/* struct read from the "device" fd,
+   consists mainly of userspace pointers for the library to use */
+struct dlm_lock_result {
+	__u32 length;
+	void __user * user_astaddr;
+	void __user * user_astparam;
+	struct dlm_lksb __user * user_lksb;
+	struct dlm_lksb lksb;
+	__u8 bast_mode;
+	/* Offsets may be zero if no data is present */
+	__u32 lvb_offset;
+};
+
+/* Commands passed to the device */
+#define DLM_USER_LOCK         1
+#define DLM_USER_UNLOCK       2
+#define DLM_USER_QUERY        3
+#define DLM_USER_CREATE_LOCKSPACE  4
+#define DLM_USER_REMOVE_LOCKSPACE  5
+
+/* Arbitrary length restriction */
+#define MAX_LS_NAME_LEN 64
+
+/* Lockspace flags */
+#define DLM_USER_LSFLG_AUTOFREE   1
+#define DLM_USER_LSFLG_FORCEFREE  2
+