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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 */
9#ifndef _LINUX_MOUNT_H
10#define _LINUX_MOUNT_H
11
12#include <linux/types.h>
13#include <linux/list.h>
14#include <linux/nodemask.h>
15#include <linux/spinlock.h>
16#include <asm/atomic.h>
17
18struct super_block;
19struct vfsmount;
20struct dentry;
21struct mnt_namespace;
22
23#define MNT_NOSUID 0x01
24#define MNT_NODEV 0x02
25#define MNT_NOEXEC 0x04
26#define MNT_NOATIME 0x08
27#define MNT_NODIRATIME 0x10
28#define MNT_RELATIME 0x20
29#define MNT_READONLY 0x40 /* does the user want this to be r/o? */
30#define MNT_STRICTATIME 0x80
31
32#define MNT_SHRINKABLE 0x100
33#define MNT_IMBALANCED_WRITE_COUNT 0x200 /* just for debugging */
34
35#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
36#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
37#define MNT_PNODE_MASK 0x3000 /* propagation flag mask */
38
39struct vfsmount {
40 struct list_head mnt_hash;
41 struct vfsmount *mnt_parent; /* fs we are mounted on */
42 struct dentry *mnt_mountpoint; /* dentry of mountpoint */
43 struct dentry *mnt_root; /* root of the mounted tree */
44 struct super_block *mnt_sb; /* pointer to superblock */
45 struct list_head mnt_mounts; /* list of children, anchored here */
46 struct list_head mnt_child; /* and going through their mnt_child */
47 int mnt_flags;
48 /* 4 bytes hole on 64bits arches */
49 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
50 struct list_head mnt_list;
51 struct list_head mnt_expire; /* link in fs-specific expiry list */
52 struct list_head mnt_share; /* circular list of shared mounts */
53 struct list_head mnt_slave_list;/* list of slave mounts */
54 struct list_head mnt_slave; /* slave list entry */
55 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
56 struct mnt_namespace *mnt_ns; /* containing namespace */
57 int mnt_id; /* mount identifier */
58 int mnt_group_id; /* peer group identifier */
59 /*
60 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
61 * to let these frequently modified fields in a separate cache line
62 * (so that reads of mnt_flags wont ping-pong on SMP machines)
63 */
64 atomic_t mnt_count;
65 int mnt_expiry_mark; /* true if marked for expiry */
66 int mnt_pinned;
67 int mnt_ghosts;
68 /*
69 * This value is not stable unless all of the mnt_writers[] spinlocks
70 * are held, and all mnt_writer[]s on this mount have 0 as their ->count
71 */
72 atomic_t __mnt_writers;
73};
74
75static inline struct vfsmount *mntget(struct vfsmount *mnt)
76{
77 if (mnt)
78 atomic_inc(&mnt->mnt_count);
79 return mnt;
80}
81
82extern int mnt_want_write(struct vfsmount *mnt);
83extern void mnt_drop_write(struct vfsmount *mnt);
84extern void mntput_no_expire(struct vfsmount *mnt);
85extern void mnt_pin(struct vfsmount *mnt);
86extern void mnt_unpin(struct vfsmount *mnt);
87extern int __mnt_is_readonly(struct vfsmount *mnt);
88
89static inline void mntput(struct vfsmount *mnt)
90{
91 if (mnt) {
92 mnt->mnt_expiry_mark = 0;
93 mntput_no_expire(mnt);
94 }
95}
96
97extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
98 const char *name, void *data);
99
100struct file_system_type;
101extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
102 int flags, const char *name,
103 void *data);
104
105struct nameidata;
106
107struct path;
108extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
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 */