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
16 struct super_block;
17 struct dentry;
18 struct user_namespace;
19 struct mnt_idmap;
20 struct file_system_type;
21 struct fs_context;
22 struct file;
23 struct path;
24
25 enum 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_INTERNAL = 0x4000,
39
40 MNT_LOCK_ATIME = 0x040000,
41 MNT_LOCK_NOEXEC = 0x080000,
42 MNT_LOCK_NOSUID = 0x100000,
43 MNT_LOCK_NODEV = 0x200000,
44 MNT_LOCK_READONLY = 0x400000,
45 MNT_LOCKED = 0x800000,
46 MNT_DOOMED = 0x1000000,
47 MNT_SYNC_UMOUNT = 0x2000000,
48 MNT_UMOUNT = 0x8000000,
49
50 MNT_USER_SETTABLE_MASK = MNT_NOSUID | MNT_NODEV | MNT_NOEXEC
51 | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME
52 | MNT_READONLY | MNT_NOSYMFOLLOW,
53 MNT_ATIME_MASK = MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME,
54
55 MNT_INTERNAL_FLAGS = MNT_WRITE_HOLD | MNT_INTERNAL | MNT_DOOMED |
56 MNT_SYNC_UMOUNT | MNT_LOCKED
57 };
58
59 struct vfsmount {
60 struct dentry *mnt_root; /* root of the mounted tree */
61 struct super_block *mnt_sb; /* pointer to superblock */
62 int mnt_flags;
63 struct mnt_idmap *mnt_idmap;
64 } __randomize_layout;
65
mnt_idmap(const struct vfsmount * mnt)66 static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt)
67 {
68 /* Pairs with smp_store_release() in do_idmap_mount(). */
69 return READ_ONCE(mnt->mnt_idmap);
70 }
71
72 extern int mnt_want_write(struct vfsmount *mnt);
73 extern int mnt_want_write_file(struct file *file);
74 extern void mnt_drop_write(struct vfsmount *mnt);
75 extern void mnt_drop_write_file(struct file *file);
76 extern void mntput(struct vfsmount *mnt);
77 extern struct vfsmount *mntget(struct vfsmount *mnt);
78 extern void mnt_make_shortterm(struct vfsmount *mnt);
79 extern struct vfsmount *mnt_clone_internal(const struct path *path);
80 extern bool __mnt_is_readonly(struct vfsmount *mnt);
81 extern bool mnt_may_suid(struct vfsmount *mnt);
82
83 extern struct vfsmount *clone_private_mount(const struct path *path);
84 int mnt_get_write_access(struct vfsmount *mnt);
85 void mnt_put_write_access(struct vfsmount *mnt);
86
87 extern struct vfsmount *fc_mount(struct fs_context *fc);
88 extern struct vfsmount *fc_mount_longterm(struct fs_context *fc);
89 extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
90 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
91 int flags, const char *name,
92 void *data);
93
94 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
95 extern void mark_mounts_for_expiry(struct list_head *mounts);
96
97 extern bool path_is_mountpoint(const struct path *path);
98
99 extern bool our_mnt(struct vfsmount *mnt);
100
101 extern struct vfsmount *kern_mount(struct file_system_type *);
102 extern void kern_unmount(struct vfsmount *mnt);
103 extern int may_umount_tree(struct vfsmount *);
104 extern int may_umount(struct vfsmount *);
105 int do_mount(const char *, const char __user *,
106 const char *, unsigned long, void *);
107 extern struct path *collect_paths(const struct path *, struct path *, unsigned);
108 extern void drop_collected_paths(struct path *, struct path *);
109 extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num);
110
111 extern int cifs_root_data(char **dev, char **opts);
112
113 #endif /* _LINUX_MOUNT_H */
114