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;
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
33#define MNT_SHRINKABLE 0x100
34#define MNT_WRITE_HOLD 0x200
35
36#define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */
37#define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */
38/*
39 * MNT_SHARED_MASK is the set of flags that should be cleared when a
40 * mount becomes shared. Currently, this is only the flag that says a
41 * mount cannot be bind mounted, since this is how we create a mount
42 * that shares events with another mount. If you add a new MNT_*
43 * flag, consider how it interacts with shared mounts.
44 */
45#define MNT_SHARED_MASK (MNT_UNBINDABLE)
46#define MNT_USER_SETTABLE_MASK (MNT_NOSUID | MNT_NODEV | MNT_NOEXEC \
47 | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME \
48 | MNT_READONLY)
49#define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
50
51#define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \
52 MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED)
53
54#define MNT_INTERNAL 0x4000
55
56#define MNT_LOCK_ATIME 0x040000
57#define MNT_LOCK_NOEXEC 0x080000
58#define MNT_LOCK_NOSUID 0x100000
59#define MNT_LOCK_NODEV 0x200000
60#define MNT_LOCK_READONLY 0x400000
61#define MNT_LOCKED 0x800000
62#define MNT_DOOMED 0x1000000
63#define MNT_SYNC_UMOUNT 0x2000000
64#define MNT_MARKED 0x4000000
65#define MNT_UMOUNT 0x8000000
66
67struct vfsmount {
68 struct dentry *mnt_root; /* root of the mounted tree */
69 struct super_block *mnt_sb; /* pointer to superblock */
70 int mnt_flags;
71} __randomize_layout;
72
73struct file; /* forward dec */
74struct path;
75
76extern int mnt_want_write(struct vfsmount *mnt);
77extern int mnt_want_write_file(struct file *file);
78extern int mnt_clone_write(struct vfsmount *mnt);
79extern void mnt_drop_write(struct vfsmount *mnt);
80extern void mnt_drop_write_file(struct file *file);
81extern void mntput(struct vfsmount *mnt);
82extern struct vfsmount *mntget(struct vfsmount *mnt);
83extern struct vfsmount *mnt_clone_internal(const struct path *path);
84extern int __mnt_is_readonly(struct vfsmount *mnt);
85extern bool mnt_may_suid(struct vfsmount *mnt);
86
87struct path;
88extern struct vfsmount *clone_private_mount(const struct path *path);
89
90struct file_system_type;
91extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
92 int flags, const char *name,
93 void *data);
94extern struct vfsmount *vfs_submount(const struct dentry *mountpoint,
95 struct file_system_type *type,
96 const char *name, void *data);
97
98extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
99extern void mark_mounts_for_expiry(struct list_head *mounts);
100
101extern dev_t name_to_dev_t(const char *name);
102
103extern unsigned int sysctl_mount_max;
104
105extern bool path_is_mountpoint(const struct path *path);
106
107#endif /* _LINUX_MOUNT_H */
108