Line data Source code
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 :
18 : struct super_block;
19 : struct vfsmount;
20 : struct dentry;
21 : struct 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_WRITE_HOLD 0x200
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 :
39 : struct 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 : #ifdef CONFIG_SMP
69 : int *mnt_writers;
70 : #else
71 : int mnt_writers;
72 : #endif
73 : };
74 :
75 : static inline int *get_mnt_writers_ptr(struct vfsmount *mnt)
76 : {
77 : #ifdef CONFIG_SMP
78 : return mnt->mnt_writers;
79 : #else
80 : return &mnt->mnt_writers;
81 : #endif
82 : }
83 :
84 : static inline struct vfsmount *mntget(struct vfsmount *mnt)
85 : {
86 : if (mnt)
87 : atomic_inc(&mnt->mnt_count);
88 : return mnt;
89 : }
90 :
91 : struct file; /* forward dec */
92 :
93 : extern int mnt_want_write(struct vfsmount *mnt);
94 : extern int mnt_want_write_file(struct file *file);
95 : extern int mnt_clone_write(struct vfsmount *mnt);
96 : extern void mnt_drop_write(struct vfsmount *mnt);
97 : extern void mntput_no_expire(struct vfsmount *mnt);
98 : extern void mnt_pin(struct vfsmount *mnt);
99 : extern void mnt_unpin(struct vfsmount *mnt);
100 : extern int __mnt_is_readonly(struct vfsmount *mnt);
101 :
102 : static inline void mntput(struct vfsmount *mnt)
103 : {
104 : if (mnt) {
105 : mnt->mnt_expiry_mark = 0;
106 : mntput_no_expire(mnt);
107 : }
108 : }
109 :
110 : extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
111 : const char *name, void *data);
112 :
113 : struct file_system_type;
114 : extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
115 : int flags, const char *name,
116 : void *data);
117 :
118 : struct nameidata;
119 :
120 : struct path;
121 : extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
122 : int mnt_flags, struct list_head *fslist);
123 :
124 : extern void mark_mounts_for_expiry(struct list_head *mounts);
125 :
126 : extern spinlock_t vfsmount_lock;
127 : extern dev_t name_to_dev_t(char *name);
128 1 :
129 : #endif /* _LINUX_MOUNT_H */
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