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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#ifdef __KERNEL__
14
15#include <linux/types.h>
16#include <linux/list.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
32#define MNT_SHRINKABLE 0x100
33
34#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
35#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
36#define MNT_PNODE_MASK 0x3000 /* propagation flag mask */
37
38struct vfsmount {
39 struct list_head mnt_hash;
40 struct vfsmount *mnt_parent; /* fs we are mounted on */
41 struct dentry *mnt_mountpoint; /* dentry of mountpoint */
42 struct dentry *mnt_root; /* root of the mounted tree */
43 struct super_block *mnt_sb; /* pointer to superblock */
44 struct list_head mnt_mounts; /* list of children, anchored here */
45 struct list_head mnt_child; /* and going through their mnt_child */
46 int mnt_flags;
47 /* 4 bytes hole on 64bits arches */
48 char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
49 struct list_head mnt_list;
50 struct list_head mnt_expire; /* link in fs-specific expiry list */
51 struct list_head mnt_share; /* circular list of shared mounts */
52 struct list_head mnt_slave_list;/* list of slave mounts */
53 struct list_head mnt_slave; /* slave list entry */
54 struct vfsmount *mnt_master; /* slave is on master->mnt_slave_list */
55 struct mnt_namespace *mnt_ns; /* containing namespace */
56 /*
57 * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
58 * to let these frequently modified fields in a separate cache line
59 * (so that reads of mnt_flags wont ping-pong on SMP machines)
60 */
61 atomic_t mnt_count;
62 int mnt_expiry_mark; /* true if marked for expiry */
63 int mnt_pinned;
64 int mnt_ghosts;
65};
66
67static inline struct vfsmount *mntget(struct vfsmount *mnt)
68{
69 if (mnt)
70 atomic_inc(&mnt->mnt_count);
71 return mnt;
72}
73
74extern void mntput_no_expire(struct vfsmount *mnt);
75extern void mnt_pin(struct vfsmount *mnt);
76extern void mnt_unpin(struct vfsmount *mnt);
77
78static inline void mntput(struct vfsmount *mnt)
79{
80 if (mnt) {
81 mnt->mnt_expiry_mark = 0;
82 mntput_no_expire(mnt);
83 }
84}
85
86extern void free_vfsmnt(struct vfsmount *mnt);
87extern struct vfsmount *alloc_vfsmnt(const char *name);
88extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
89 const char *name, void *data);
90
91struct file_system_type;
92extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
93 int flags, const char *name,
94 void *data);
95
96struct nameidata;
97
98extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
99 int mnt_flags, struct list_head *fslist);
100
101extern void mark_mounts_for_expiry(struct list_head *mounts);
102
103extern spinlock_t vfsmount_lock;
104extern dev_t name_to_dev_t(char *name);
105
106#endif
107#endif /* _LINUX_MOUNT_H */