mount.h (4382B)
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 file_system_type; 20struct fs_context; 21struct file; 22struct path; 23 24#define MNT_NOSUID 0x01 25#define MNT_NODEV 0x02 26#define MNT_NOEXEC 0x04 27#define MNT_NOATIME 0x08 28#define MNT_NODIRATIME 0x10 29#define MNT_RELATIME 0x20 30#define MNT_READONLY 0x40 /* does the user want this to be r/o? */ 31#define MNT_NOSYMFOLLOW 0x80 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 | MNT_NOSYMFOLLOW) 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 MNT_CURSOR) 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_CURSOR 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 user_namespace *mnt_userns; 74} __randomize_layout; 75 76static inline struct user_namespace *mnt_user_ns(const struct vfsmount *mnt) 77{ 78 /* Pairs with smp_store_release() in do_idmap_mount(). */ 79 return smp_load_acquire(&mnt->mnt_userns); 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 struct vfsmount *mnt_clone_internal(const struct path *path); 89extern bool __mnt_is_readonly(struct vfsmount *mnt); 90extern bool mnt_may_suid(struct vfsmount *mnt); 91 92extern struct vfsmount *clone_private_mount(const struct path *path); 93extern int __mnt_want_write(struct vfsmount *); 94extern void __mnt_drop_write(struct vfsmount *); 95 96extern struct vfsmount *fc_mount(struct fs_context *fc); 97extern struct vfsmount *vfs_create_mount(struct fs_context *fc); 98extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 99 int flags, const char *name, 100 void *data); 101extern struct vfsmount *vfs_submount(const struct dentry *mountpoint, 102 struct file_system_type *type, 103 const char *name, void *data); 104 105extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list); 106extern void mark_mounts_for_expiry(struct list_head *mounts); 107 108extern dev_t name_to_dev_t(const char *name); 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); 124 125#endif /* _LINUX_MOUNT_H */