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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *
4 * Definitions for mount interface. This describes the in the kernel build
5 * linkedlist with mounted filesystems.
6 *
7 * Author: Marco van Wieringen <mvw@planets.elm.net>
8 *
9 */
10#ifndef _LINUX_MOUNT_H
11#define _LINUX_MOUNT_H
12
13#include <linux/types.h>
14#include <asm/barrier.h>
15
16struct super_block;
17struct dentry;
18struct user_namespace;
19struct mnt_idmap;
20struct file_system_type;
21struct fs_context;
22struct file;
23struct path;
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#define MNT_READONLY 0x40 /* does the user want this to be r/o? */
32#define MNT_NOSYMFOLLOW 0x80
33
34#define MNT_SHRINKABLE 0x100
35#define MNT_WRITE_HOLD 0x200
36
37#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
38#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
39/*
40 * MNT_SHARED_MASK is the set of flags that should be cleared when a
41 * mount becomes shared. Currently, this is only the flag that says a
42 * mount cannot be bind mounted, since this is how we create a mount
43 * that shares events with another mount. If you add a new MNT_*
44 * flag, consider how it interacts with shared mounts.
45 */
46#define MNT_SHARED_MASK (MNT_UNBINDABLE)
47#define MNT_USER_SETTABLE_MASK (MNT_NOSUID | MNT_NODEV | MNT_NOEXEC \
48 | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME \
49 | MNT_READONLY | MNT_NOSYMFOLLOW)
50#define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
51
52#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
53 MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
54
55#define MNT_INTERNAL 0x4000
56
57#define MNT_LOCK_ATIME 0x040000
58#define MNT_LOCK_NOEXEC 0x080000
59#define MNT_LOCK_NOSUID 0x100000
60#define MNT_LOCK_NODEV 0x200000
61#define MNT_LOCK_READONLY 0x400000
62#define MNT_LOCKED 0x800000
63#define MNT_DOOMED 0x1000000
64#define MNT_SYNC_UMOUNT 0x2000000
65#define MNT_MARKED 0x4000000
66#define MNT_UMOUNT 0x8000000
67
68struct vfsmount {
69 struct dentry *mnt_root; /* root of the mounted tree */
70 struct super_block *mnt_sb; /* pointer to superblock */
71 int mnt_flags;
72 struct mnt_idmap *mnt_idmap;
73} __randomize_layout;
74
75static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt)
76{
77 /* Pairs with smp_store_release() in do_idmap_mount(). */
78 return READ_ONCE(mnt->mnt_idmap);
79}
80
81extern int mnt_want_write(struct vfsmount *mnt);
82extern int mnt_want_write_file(struct file *file);
83extern void mnt_drop_write(struct vfsmount *mnt);
84extern void mnt_drop_write_file(struct file *file);
85extern void mntput(struct vfsmount *mnt);
86extern struct vfsmount *mntget(struct vfsmount *mnt);
87extern void mnt_make_shortterm(struct vfsmount *mnt);
88extern struct vfsmount *mnt_clone_internal(const struct path *path);
89extern bool __mnt_is_readonly(struct vfsmount *mnt);
90extern bool mnt_may_suid(struct vfsmount *mnt);
91
92extern struct vfsmount *clone_private_mount(const struct path *path);
93int mnt_get_write_access(struct vfsmount *mnt);
94void mnt_put_write_access(struct vfsmount *mnt);
95
96extern struct vfsmount *fc_mount(struct fs_context *fc);
97extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
98extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
99 int flags, const char *name,
100 void *data);
101extern struct vfsmount *vfs_submount(const struct dentry *mountpoint,
102 struct file_system_type *type,
103 const char *name, void *data);
104
105extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
106extern void mark_mounts_for_expiry(struct list_head *mounts);
107
108extern bool path_is_mountpoint(const struct path *path);
109
110extern bool our_mnt(struct vfsmount *mnt);
111
112extern struct vfsmount *kern_mount(struct file_system_type *);
113extern void kern_unmount(struct vfsmount *mnt);
114extern int may_umount_tree(struct vfsmount *);
115extern int may_umount(struct vfsmount *);
116int do_mount(const char *, const char __user *,
117 const char *, unsigned long, void *);
118extern struct vfsmount *collect_mounts(const struct path *);
119extern void drop_collected_mounts(struct vfsmount *);
120extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
121 struct vfsmount *);
122extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num);
123
124extern int cifs_root_data(char **dev, char **opts);
125
126#endif /* _LINUX_MOUNT_H */