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1/*
2 *
3 * Definitions for mount interface. This describes the in the kernel build
4 * linkedlist with mounted filesystems.
5 *
6 * Author: Marco van Wieringen <mvw@planets.elm.net>
7 *
8 * Version: $Id: mount.h,v 2.0 1996/11/17 16:48:14 mvw Exp mvw $
9 *
10 */
11#ifndef _LINUX_MOUNT_H
12#define _LINUX_MOUNT_H
13
14#include <linux/types.h>
15#include <linux/list.h>
16#include <linux/nodemask.h>
17#include <linux/spinlock.h>
18#include <asm/atomic.h>
19
20struct super_block;
21struct vfsmount;
22struct dentry;
23struct mnt_namespace;
24
25#define MNT_NOSUID 0x01
26#define MNT_NODEV 0x02
27#define MNT_NOEXEC 0x04
28#define MNT_NOATIME 0x08
29#define MNT_NODIRATIME 0x10
30#define MNT_RELATIME 0x20
31#define MNT_READONLY 0x40 /* does the user want this to be r/o? */
32
33#define MNT_SHRINKABLE 0x100
34#define MNT_IMBALANCED_WRITE_COUNT 0x200 /* just for debugging */
35
36#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
37#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
38#define MNT_PNODE_MASK 0x3000 /* propagation flag mask */
39
40struct vfsmount {
41 struct list_head mnt_hash;
42 struct vfsmount *mnt_parent; /* fs we are mounted on */
43 struct dentry *mnt_mountpoint; /* dentry of mountpoint */
44 struct dentry *mnt_root; /* root of the mounted tree */
45 struct super_block *mnt_sb; /* pointer to superblock */
46 struct list_head mnt_mounts; /* list of children, anchored here */
47 struct list_head mnt_child; /* and going through their mnt_child */
48 int mnt_flags;
49 /* 4 bytes hole on 64bits arches */
50 char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
51 struct list_head mnt_list;
52 struct list_head mnt_expire; /* link in fs-specific expiry list */
53 struct list_head mnt_share; /* circular list of shared mounts */
54 struct list_head mnt_slave_list;/* list of slave mounts */
55 struct list_head mnt_slave; /* slave list entry */
56 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
57 struct mnt_namespace *mnt_ns; /* containing namespace */
58 int mnt_id; /* mount identifier */
59 int mnt_group_id; /* peer group identifier */
60 /*
61 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
62 * to let these frequently modified fields in a separate cache line
63 * (so that reads of mnt_flags wont ping-pong on SMP machines)
64 */
65 atomic_t mnt_count;
66 int mnt_expiry_mark; /* true if marked for expiry */
67 int mnt_pinned;
68 int mnt_ghosts;
69 /*
70 * This value is not stable unless all of the mnt_writers[] spinlocks
71 * are held, and all mnt_writer[]s on this mount have 0 as their ->count
72 */
73 atomic_t __mnt_writers;
74};
75
76static inline struct vfsmount *mntget(struct vfsmount *mnt)
77{
78 if (mnt)
79 atomic_inc(&mnt->mnt_count);
80 return mnt;
81}
82
83extern int mnt_want_write(struct vfsmount *mnt);
84extern void mnt_drop_write(struct vfsmount *mnt);
85extern void mntput_no_expire(struct vfsmount *mnt);
86extern void mnt_pin(struct vfsmount *mnt);
87extern void mnt_unpin(struct vfsmount *mnt);
88extern int __mnt_is_readonly(struct vfsmount *mnt);
89
90static inline void mntput(struct vfsmount *mnt)
91{
92 if (mnt) {
93 mnt->mnt_expiry_mark = 0;
94 mntput_no_expire(mnt);
95 }
96}
97
98extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
99 const char *name, void *data);
100
101struct file_system_type;
102extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
103 int flags, const char *name,
104 void *data);
105
106struct nameidata;
107
108extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
109 int mnt_flags, struct list_head *fslist);
110
111extern void mark_mounts_for_expiry(struct list_head *mounts);
112
113extern spinlock_t vfsmount_lock;
114extern dev_t name_to_dev_t(char *name);
115
116#endif /* _LINUX_MOUNT_H */