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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070013
Andrew Mortond53d9f12005-07-12 13:58:07 -070014#include <linux/types.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/list.h>
Dave Hansen3d733632008-02-15 14:37:59 -080016#include <linux/nodemask.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/spinlock.h>
18#include <asm/atomic.h>
19
David Howells726c3342006-06-23 02:02:58 -070020struct super_block;
21struct vfsmount;
22struct dentry;
Kirill Korotaev6b3286e2006-12-08 02:37:56 -080023struct mnt_namespace;
David Howells726c3342006-06-23 02:02:58 -070024
Ram Pai07b20882005-11-07 17:19:07 -050025#define MNT_NOSUID 0x01
26#define MNT_NODEV 0x02
27#define MNT_NOEXEC 0x04
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -080028#define MNT_NOATIME 0x08
29#define MNT_NODIRATIME 0x10
Valerie Henson47ae32d2006-12-13 00:34:34 -080030#define MNT_RELATIME 0x20
Dave Hansen2e4b7fc2008-02-15 14:38:00 -080031#define MNT_READONLY 0x40 /* does the user want this to be r/o? */
Miklos Szeredibf066c72006-01-08 01:03:19 -080032
Trond Myklebust5528f9112006-06-09 09:34:17 -040033#define MNT_SHRINKABLE 0x100
Dave Hansen3d733632008-02-15 14:37:59 -080034#define MNT_IMBALANCED_WRITE_COUNT 0x200 /* just for debugging */
Trond Myklebust5528f9112006-06-09 09:34:17 -040035
Christoph Hellwigfc33a7b2006-01-09 20:52:17 -080036#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
37#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
Robert P. J. Daybeb7dd82007-05-09 07:14:03 +020038#define MNT_PNODE_MASK 0x3000 /* propagation flag mask */
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Ram Pai07b20882005-11-07 17:19:07 -050040struct vfsmount {
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 int mnt_flags;
Eric Dumazet4ba4d4c2007-02-10 01:44:48 -080049 /* 4 bytes hole on 64bits arches */
Li Zefan88b38782008-07-21 18:06:36 +080050 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 struct list_head mnt_list;
Miklos Szeredi55e700b2005-07-07 17:57:30 -070052 struct list_head mnt_expire; /* link in fs-specific expiry list */
Ram Pai03e06e62005-11-07 17:19:33 -050053 struct list_head mnt_share; /* circular list of shared mounts */
Ram Paia58b0eb2005-11-07 17:20:48 -050054 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 */
Kirill Korotaev6b3286e2006-12-08 02:37:56 -080057 struct mnt_namespace *mnt_ns; /* containing namespace */
Miklos Szeredi73cd49e2008-03-26 22:11:34 +010058 int mnt_id; /* mount identifier */
Miklos Szeredi719f5d72008-03-27 13:06:23 +010059 int mnt_group_id; /* peer group identifier */
Eric Dumazet4ba4d4c2007-02-10 01:44:48 -080060 /*
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 */
Al Viro7b7b1ac2005-11-07 17:13:39 -050067 int mnt_pinned;
Al Viro7c4b93d2008-03-21 23:59:49 -040068 int mnt_ghosts;
Dave Hansen3d733632008-02-15 14:37:59 -080069 /*
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074};
75
76static inline struct vfsmount *mntget(struct vfsmount *mnt)
77{
78 if (mnt)
79 atomic_inc(&mnt->mnt_count);
80 return mnt;
81}
82
Dave Hansen83660252008-02-15 14:37:30 -080083extern int mnt_want_write(struct vfsmount *mnt);
84extern void mnt_drop_write(struct vfsmount *mnt);
Al Viro7b7b1ac2005-11-07 17:13:39 -050085extern void mntput_no_expire(struct vfsmount *mnt);
86extern void mnt_pin(struct vfsmount *mnt);
87extern void mnt_unpin(struct vfsmount *mnt);
Dave Hansen83660252008-02-15 14:37:30 -080088extern int __mnt_is_readonly(struct vfsmount *mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
90static inline void mntput(struct vfsmount *mnt)
91{
92 if (mnt) {
93 mnt->mnt_expiry_mark = 0;
Miklos Szeredi751c4042005-07-07 17:57:30 -070094 mntput_no_expire(mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 }
96}
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
99 const char *name, void *data);
100
Trond Myklebustbb4a58b2006-06-09 09:34:15 -0400101struct file_system_type;
102extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
103 int flags, const char *name,
104 void *data);
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106struct 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;
Andrew Mortond53d9f12005-07-12 13:58:07 -0700114extern dev_t name_to_dev_t(char *name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116#endif /* _LINUX_MOUNT_H */