Merge tag 'dlm-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm

Pull dlm update from David Teigland:
"This set includes one feature, which allows locks that have been
orphaned to be reacquired"

* tag 'dlm-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
dlm: adopt orphan locks

fs/dlm/lock.c

···
 	return error;
 }
 
+/*
+ * The caller asks for an orphan lock on a given resource with a given mode.
+ * If a matching lock exists, it's moved to the owner's list of locks and
+ * the lkid is returned.
+ */
+
+int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
+		     int mode, uint32_t flags, void *name, unsigned int namelen,
+		     unsigned long timeout_cs, uint32_t *lkid)
+{
+	struct dlm_lkb *lkb;
+	struct dlm_user_args *ua;
+	int found_other_mode = 0;
+	int found = 0;
+	int rv = 0;
+
+	mutex_lock(&ls->ls_orphans_mutex);
+	list_for_each_entry(lkb, &ls->ls_orphans, lkb_ownqueue) {
+		if (lkb->lkb_resource->res_length != namelen)
+			continue;
+		if (memcmp(lkb->lkb_resource->res_name, name, namelen))
+			continue;
+		if (lkb->lkb_grmode != mode) {
+			found_other_mode = 1;
+			continue;
+		}
+
+		found = 1;
+		list_del_init(&lkb->lkb_ownqueue);
+		lkb->lkb_flags &= ~DLM_IFL_ORPHAN;
+		*lkid = lkb->lkb_id;
+		break;
+	}
+	mutex_unlock(&ls->ls_orphans_mutex);
+
+	if (!found && found_other_mode) {
+		rv = -EAGAIN;
+		goto out;
+	}
+
+	if (!found) {
+		rv = -ENOENT;
+		goto out;
+	}
+
+	lkb->lkb_exflags = flags;
+	lkb->lkb_ownpid = (int) current->pid;
+
+	ua = lkb->lkb_ua;
+
+	ua->proc = ua_tmp->proc;
+	ua->xid = ua_tmp->xid;
+	ua->castparam = ua_tmp->castparam;
+	ua->castaddr = ua_tmp->castaddr;
+	ua->bastparam = ua_tmp->bastparam;
+	ua->bastaddr = ua_tmp->bastaddr;
+	ua->user_lksb = ua_tmp->user_lksb;
+
+	/*
+	 * The lkb reference from the ls_orphans list was not
+	 * removed above, and is now considered the reference
+	 * for the proc locks list.
+	 */
+
+	spin_lock(&ua->proc->locks_spin);
+	list_add_tail(&lkb->lkb_ownqueue, &ua->proc->locks);
+	spin_unlock(&ua->proc->locks_spin);
+ out:
+	kfree(ua_tmp);
+	return rv;
+}
+
 int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 		    uint32_t flags, uint32_t lkid, char *lvb_in)
 {
···
 	struct dlm_args args;
 	int error;
 
-	hold_lkb(lkb);
+	hold_lkb(lkb); /* reference for the ls_orphans list */
 	mutex_lock(&ls->ls_orphans_mutex);
 	list_add_tail(&lkb->lkb_ownqueue, &ls->ls_orphans);
 	mutex_unlock(&ls->ls_orphans_mutex);
···
 {
 	int error = 0;
 
-	if (nodeid != dlm_our_nodeid()) {
+	if (nodeid && (nodeid != dlm_our_nodeid())) {
 		error = send_purge(ls, nodeid, pid);
 	} else {
 		dlm_lock_recovery(ls);

fs/dlm/lock.h

···
 int dlm_user_convert(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	int mode, uint32_t flags, uint32_t lkid, char *lvb_in,
 	unsigned long timeout_cs);
+int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
+	int mode, uint32_t flags, void *name, unsigned int namelen,
+	unsigned long timeout_cs, uint32_t *lkid);
 int dlm_user_unlock(struct dlm_ls *ls, struct dlm_user_args *ua_tmp,
 	uint32_t flags, uint32_t lkid, char *lvb_in);
 int dlm_user_cancel(struct dlm_ls *ls,  struct dlm_user_args *ua_tmp,

fs/dlm/user.c

···
 {
 	struct dlm_ls *ls;
 	struct dlm_user_args *ua;
+	uint32_t lkid;
 	int error = -ENOMEM;
 
 	ls = dlm_find_lockspace_local(proc->lockspace);
···
 	ua->bastaddr = params->bastaddr;
 	ua->xid = params->xid;
 
-	if (params->flags & DLM_LKF_CONVERT)
+	if (params->flags & DLM_LKF_CONVERT) {
 		error = dlm_user_convert(ls, ua,
 				         params->mode, params->flags,
 				         params->lkid, params->lvb,
 					 (unsigned long) params->timeout);
-	else {
+	} else if (params->flags & DLM_LKF_ORPHAN) {
+		error = dlm_user_adopt_orphan(ls, ua,
+					 params->mode, params->flags,
+					 params->name, params->namelen,
+					 (unsigned long) params->timeout,
+					 &lkid);
+		if (!error)
+			error = lkid;
+	} else {
 		error = dlm_user_request(ls, ua,
 					 params->mode, params->flags,
 					 params->name, params->namelen,

include/uapi/linux/dlmconstants.h

···
  *
  * DLM_LKF_ORPHAN
  *
- * not yet implemented
+ * Acquire an orphan lock.
  *
  * DLM_LKF_ALTPR
  *