[PATCH] r/o bind mounts: track numbers of writers to mounts
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / linux / mount.h
CommitLineData
1da177e4
LT
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#ifdef __KERNEL__
14
d53d9f16 15#include <linux/types.h>
1da177e4 16#include <linux/list.h>
3d733633 17#include <linux/nodemask.h>
1da177e4
LT
18#include <linux/spinlock.h>
19#include <asm/atomic.h>
20
726c3342
DH
21struct super_block;
22struct vfsmount;
23struct dentry;
6b3286ed 24struct mnt_namespace;
726c3342 25
07b20889
RP
26#define MNT_NOSUID 0x01
27#define MNT_NODEV 0x02
28#define MNT_NOEXEC 0x04
fc33a7bb
CH
29#define MNT_NOATIME 0x08
30#define MNT_NODIRATIME 0x10
47ae32d6 31#define MNT_RELATIME 0x20
bf066c7d 32
5528f911 33#define MNT_SHRINKABLE 0x100
3d733633 34#define MNT_IMBALANCED_WRITE_COUNT 0x200 /* just for debugging */
5528f911 35
fc33a7bb
CH
36#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
37#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
beb7dd86 38#define MNT_PNODE_MASK 0x3000 /* propagation flag mask */
1da177e4 39
07b20889 40struct vfsmount {
1da177e4
LT
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 */
1da177e4 48 int mnt_flags;
4ba4d4c0 49 /* 4 bytes hole on 64bits arches */
1da177e4
LT
50 char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
51 struct list_head mnt_list;
55e700b9 52 struct list_head mnt_expire; /* link in fs-specific expiry list */
03e06e68 53 struct list_head mnt_share; /* circular list of shared mounts */
a58b0eb8
RP
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 */
6b3286ed 57 struct mnt_namespace *mnt_ns; /* containing namespace */
4ba4d4c0
ED
58 /*
59 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
60 * to let these frequently modified fields in a separate cache line
61 * (so that reads of mnt_flags wont ping-pong on SMP machines)
62 */
63 atomic_t mnt_count;
64 int mnt_expiry_mark; /* true if marked for expiry */
7b7b1ace 65 int mnt_pinned;
7c4b93d8 66 int mnt_ghosts;
3d733633
DH
67 /*
68 * This value is not stable unless all of the mnt_writers[] spinlocks
69 * are held, and all mnt_writer[]s on this mount have 0 as their ->count
70 */
71 atomic_t __mnt_writers;
1da177e4
LT
72};
73
74static inline struct vfsmount *mntget(struct vfsmount *mnt)
75{
76 if (mnt)
77 atomic_inc(&mnt->mnt_count);
78 return mnt;
79}
80
8366025e
DH
81extern int mnt_want_write(struct vfsmount *mnt);
82extern void mnt_drop_write(struct vfsmount *mnt);
7b7b1ace
AV
83extern void mntput_no_expire(struct vfsmount *mnt);
84extern void mnt_pin(struct vfsmount *mnt);
85extern void mnt_unpin(struct vfsmount *mnt);
8366025e 86extern int __mnt_is_readonly(struct vfsmount *mnt);
1da177e4
LT
87
88static inline void mntput(struct vfsmount *mnt)
89{
90 if (mnt) {
91 mnt->mnt_expiry_mark = 0;
751c404b 92 mntput_no_expire(mnt);
1da177e4
LT
93 }
94}
95
96extern void free_vfsmnt(struct vfsmount *mnt);
97extern struct vfsmount *alloc_vfsmnt(const char *name);
98extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
99 const char *name, void *data);
100
bb4a58bf
TM
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
1da177e4
LT
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;
d53d9f16 114extern dev_t name_to_dev_t(char *name);
1da177e4
LT
115
116#endif
117#endif /* _LINUX_MOUNT_H */