mount.h

  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
 37	MNT_INTERNAL	= 0x4000,
 38
 39	MNT_LOCK_ATIME		= 0x040000,
 40	MNT_LOCK_NOEXEC		= 0x080000,
 41	MNT_LOCK_NOSUID		= 0x100000,
 42	MNT_LOCK_NODEV		= 0x200000,
 43	MNT_LOCK_READONLY	= 0x400000,
 44	MNT_LOCKED		= 0x800000,
 45	MNT_DOOMED		= 0x1000000,
 46	MNT_SYNC_UMOUNT		= 0x2000000,
 47	MNT_UMOUNT		= 0x8000000,
 48
 49	MNT_USER_SETTABLE_MASK  = MNT_NOSUID | MNT_NODEV | MNT_NOEXEC
 50				  | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME
 51				  | MNT_READONLY | MNT_NOSYMFOLLOW,
 52	MNT_ATIME_MASK = MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME,
 53
 54	MNT_INTERNAL_FLAGS = MNT_INTERNAL | MNT_DOOMED |
 55			     MNT_SYNC_UMOUNT | MNT_LOCKED
 56};
 57
 58struct vfsmount {
 59	struct dentry *mnt_root;	/* root of the mounted tree */
 60	struct super_block *mnt_sb;	/* pointer to superblock */
 61	int mnt_flags;
 62	struct mnt_idmap *mnt_idmap;
 63} __randomize_layout;
 64
 65static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt)
 66{
 67	/* Pairs with smp_store_release() in do_idmap_mount(). */
 68	return READ_ONCE(mnt->mnt_idmap);
 69}
 70
 71extern int mnt_want_write(struct vfsmount *mnt);
 72extern int mnt_want_write_file(struct file *file);
 73extern void mnt_drop_write(struct vfsmount *mnt);
 74extern void mnt_drop_write_file(struct file *file);
 75extern void mntput(struct vfsmount *mnt);
 76extern struct vfsmount *mntget(struct vfsmount *mnt);
 77extern void mnt_make_shortterm(struct vfsmount *mnt);
 78extern struct vfsmount *mnt_clone_internal(const struct path *path);
 79extern bool __mnt_is_readonly(const struct vfsmount *mnt);
 80extern bool mnt_may_suid(struct vfsmount *mnt);
 81
 82extern struct vfsmount *clone_private_mount(const struct path *path);
 83int mnt_get_write_access(struct vfsmount *mnt);
 84void mnt_put_write_access(struct vfsmount *mnt);
 85
 86extern struct vfsmount *fc_mount(struct fs_context *fc);
 87extern struct vfsmount *fc_mount_longterm(struct fs_context *fc);
 88extern struct vfsmount *vfs_create_mount(struct fs_context *fc);
 89extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
 90				      int flags, const char *name,
 91				      void *data);
 92
 93extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
 94extern void mark_mounts_for_expiry(struct list_head *mounts);
 95
 96extern bool path_is_mountpoint(const struct path *path);
 97
 98extern bool our_mnt(struct vfsmount *mnt);
 99
100extern struct vfsmount *kern_mount(struct file_system_type *);
101extern void kern_unmount(struct vfsmount *mnt);
102extern int may_umount_tree(struct vfsmount *);
103extern int may_umount(struct vfsmount *);
104int do_mount(const char *, const char __user *,
105		     const char *, unsigned long, void *);
106extern const struct path *collect_paths(const struct path *, struct path *, unsigned);
107extern void drop_collected_paths(const struct path *, const struct path *);
108extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num);
109
110extern int cifs_root_data(char **dev, char **opts);
111
112#endif /* _LINUX_MOUNT_H */