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
25enum mount_flags {
26 MNT_NOSUID = 0x01,
27 MNT_NODEV = 0x02,
28 MNT_NOEXEC = 0x04,
29 MNT_NOATIME = 0x08,
30 MNT_NODIRATIME = 0x10,
31 MNT_RELATIME = 0x20,
32 MNT_READONLY = 0x40, /* does the user want this to be r/o? */
33 MNT_NOSYMFOLLOW = 0x80,
34
35 MNT_SHRINKABLE = 0x100,
36 MNT_WRITE_HOLD = 0x200,
37
38 MNT_SHARED = 0x1000, /* if the vfsmount is a shared mount */
39 MNT_UNBINDABLE = 0x2000, /* if the vfsmount is a unbindable mount */
40
41 MNT_INTERNAL = 0x4000,
42
43 MNT_LOCK_ATIME = 0x040000,
44 MNT_LOCK_NOEXEC = 0x080000,
45 MNT_LOCK_NOSUID = 0x100000,
46 MNT_LOCK_NODEV = 0x200000,
47 MNT_LOCK_READONLY = 0x400000,
48 MNT_LOCKED = 0x800000,
49 MNT_DOOMED = 0x1000000,
50 MNT_SYNC_UMOUNT = 0x2000000,
51 MNT_MARKED = 0x4000000,
52 MNT_UMOUNT = 0x8000000,
53
54 /*
55 * MNT_SHARED_MASK is the set of flags that should be cleared when a
56 * mount becomes shared. Currently, this is only the flag that says a
57 * mount cannot be bind mounted, since this is how we create a mount
58 * that shares events with another mount. If you add a new MNT_*
59 * flag, consider how it interacts with shared mounts.
60 */
61 MNT_SHARED_MASK = MNT_UNBINDABLE,
62 MNT_USER_SETTABLE_MASK = MNT_NOSUID | MNT_NODEV | MNT_NOEXEC
63 | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME
64 | MNT_READONLY | MNT_NOSYMFOLLOW,
65 MNT_ATIME_MASK = MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME,
66
67 MNT_INTERNAL_FLAGS = MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL |
68 MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED |
69 MNT_LOCKED,
70};
71
72struct vfsmount {
73 struct dentry *mnt_root; /* root of the mounted tree */
74 struct super_block *mnt_sb; /* pointer to superblock */
75 int mnt_flags;
76 struct mnt_idmap *mnt_idmap;
77} __randomize_layout;
78
79static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt)
80{
81 /* Pairs with smp_store_release() in do_idmap_mount(). */
82 return READ_ONCE(mnt->mnt_idmap);
83}
84
85extern int mnt_want_write(struct vfsmount *mnt);
86extern int mnt_want_write_file(struct file *file);
87extern void mnt_drop_write(struct vfsmount *mnt);
88extern void mnt_drop_write_file(struct file *file);
89extern void mntput(struct vfsmount *mnt);
90extern struct vfsmount *mntget(struct vfsmount *mnt);
91extern void mnt_make_shortterm(struct vfsmount *mnt);
92extern struct vfsmount *mnt_clone_internal(const struct path *path);
93extern bool __mnt_is_readonly(struct vfsmount *mnt);
94extern bool mnt_may_suid(struct vfsmount *mnt);
95
96extern struct vfsmount *clone_private_mount(const struct path *path);
97int mnt_get_write_access(struct vfsmount *mnt);
98void mnt_put_write_access(struct vfsmount *mnt);
99
100extern struct vfsmount *fc_mount(struct fs_context *fc);
101extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
102extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
103 int flags, const char *name,
104 void *data);
105
106extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
107extern void mark_mounts_for_expiry(struct list_head *mounts);
108
109extern bool path_is_mountpoint(const struct path *path);
110
111extern bool our_mnt(struct vfsmount *mnt);
112
113extern struct vfsmount *kern_mount(struct file_system_type *);
114extern void kern_unmount(struct vfsmount *mnt);
115extern int may_umount_tree(struct vfsmount *);
116extern int may_umount(struct vfsmount *);
117int do_mount(const char *, const char __user *,
118 const char *, unsigned long, void *);
119extern struct vfsmount *collect_mounts(const struct path *);
120extern void drop_collected_mounts(struct vfsmount *);
121extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
122 struct vfsmount *);
123extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num);
124
125extern int cifs_root_data(char **dev, char **opts);
126
127#endif /* _LINUX_MOUNT_H */
128

source code of linux/include/linux/mount.h

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