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 <linux/list.h>
15#include <linux/nodemask.h>
16#include <linux/spinlock.h>
17#include <linux/seqlock.h>
18#include <linux/atomic.h>
19
20struct super_block;
21struct vfsmount;
22struct dentry;
23struct mnt_namespace;
24struct fs_context;
25
26#define MNT_NOSUID 0x01
27#define MNT_NODEV 0x02
28#define MNT_NOEXEC 0x04
29#define MNT_NOATIME 0x08
30#define MNT_NODIRATIME 0x10
31#define MNT_RELATIME 0x20
32#define MNT_READONLY 0x40 /* does the user want this to be r/o? */
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)
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} __randomize_layout;
73
74struct file; /* forward dec */
75struct path;
76
77extern int mnt_want_write(struct vfsmount *mnt);
78extern int mnt_want_write_file(struct file *file);
79extern int mnt_clone_write(struct vfsmount *mnt);
80extern void mnt_drop_write(struct vfsmount *mnt);
81extern void mnt_drop_write_file(struct file *file);
82extern void mntput(struct vfsmount *mnt);
83extern struct vfsmount *mntget(struct vfsmount *mnt);
84extern struct vfsmount *mnt_clone_internal(const struct path *path);
85extern bool __mnt_is_readonly(struct vfsmount *mnt);
86extern bool mnt_may_suid(struct vfsmount *mnt);
87
88struct path;
89extern struct vfsmount *clone_private_mount(const struct path *path);
90
91struct file_system_type;
92extern struct vfsmount *fc_mount(struct fs_context *fc);
93extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
94extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
95 int flags, const char *name,
96 void *data);
97extern struct vfsmount *vfs_submount(const struct dentry *mountpoint,
98 struct file_system_type *type,
99 const char *name, void *data);
100
101extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
102extern void mark_mounts_for_expiry(struct list_head *mounts);
103
104extern dev_t name_to_dev_t(const char *name);
105
106extern unsigned int sysctl_mount_max;
107
108extern bool path_is_mountpoint(const struct path *path);
109
110#endif /* _LINUX_MOUNT_H */
111