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 | MNT_ONRB)
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#define MNT_ONRB		0x10000000
68
69struct vfsmount {
70	struct dentry *mnt_root;	/* root of the mounted tree */
71	struct super_block *mnt_sb;	/* pointer to superblock */
72	int mnt_flags;
73	struct mnt_idmap *mnt_idmap;
74} __randomize_layout;
75
76static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt)
77{
78	/* Pairs with smp_store_release() in do_idmap_mount(). */
79	return smp_load_acquire(&mnt->mnt_idmap);
80}
81
82extern int mnt_want_write(struct vfsmount *mnt);
83extern int mnt_want_write_file(struct file *file);
84extern void mnt_drop_write(struct vfsmount *mnt);
85extern void mnt_drop_write_file(struct file *file);
86extern void mntput(struct vfsmount *mnt);
87extern struct vfsmount *mntget(struct vfsmount *mnt);
88extern void mnt_make_shortterm(struct vfsmount *mnt);
89extern struct vfsmount *mnt_clone_internal(const struct path *path);
90extern bool __mnt_is_readonly(struct vfsmount *mnt);
91extern bool mnt_may_suid(struct vfsmount *mnt);
92
93extern struct vfsmount *clone_private_mount(const struct path *path);
94int mnt_get_write_access(struct vfsmount *mnt);
95void mnt_put_write_access(struct vfsmount *mnt);
96
97extern struct vfsmount *fc_mount(struct fs_context *fc);
98extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
99extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
100				      int flags, const char *name,
101				      void *data);
102extern struct vfsmount *vfs_submount(const struct dentry *mountpoint,
103				     struct file_system_type *type,
104				     const char *name, 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 *);
117extern long 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