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 #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 | \ 54 MNT_CURSOR) 55 56 #define MNT_INTERNAL 0x4000 57 58 #define MNT_LOCK_ATIME 0x040000 59 #define MNT_LOCK_NOEXEC 0x080000 60 #define MNT_LOCK_NOSUID 0x100000 61 #define MNT_LOCK_NODEV 0x200000 62 #define MNT_LOCK_READONLY 0x400000 63 #define MNT_LOCKED 0x800000 64 #define MNT_DOOMED 0x1000000 65 #define MNT_SYNC_UMOUNT 0x2000000 66 #define MNT_MARKED 0x4000000 67 #define MNT_UMOUNT 0x8000000 68 #define MNT_CURSOR 0x10000000 69 70 struct vfsmount { 71 struct dentry *mnt_root; /* root of the mounted tree */ 72 struct super_block *mnt_sb; /* pointer to superblock */ 73 int mnt_flags; 74 struct mnt_idmap *mnt_idmap; 75 } __randomize_layout; 76 77 static inline struct mnt_idmap *mnt_idmap(const struct vfsmount *mnt) 78 { 79 /* Pairs with smp_store_release() in do_idmap_mount(). */ 80 return smp_load_acquire(&mnt->mnt_idmap); 81 } 82 83 extern int mnt_want_write(struct vfsmount *mnt); 84 extern int mnt_want_write_file(struct file *file); 85 extern void mnt_drop_write(struct vfsmount *mnt); 86 extern void mnt_drop_write_file(struct file *file); 87 extern void mntput(struct vfsmount *mnt); 88 extern struct vfsmount *mntget(struct vfsmount *mnt); 89 extern void mnt_make_shortterm(struct vfsmount *mnt); 90 extern struct vfsmount *mnt_clone_internal(const struct path *path); 91 extern bool __mnt_is_readonly(struct vfsmount *mnt); 92 extern bool mnt_may_suid(struct vfsmount *mnt); 93 94 extern struct vfsmount *clone_private_mount(const struct path *path); 95 extern int __mnt_want_write(struct vfsmount *); 96 extern void __mnt_drop_write(struct vfsmount *); 97 98 extern struct vfsmount *fc_mount(struct fs_context *fc); 99 extern struct vfsmount *vfs_create_mount(struct fs_context *fc); 100 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 101 int flags, const char *name, 102 void *data); 103 extern struct vfsmount *vfs_submount(const struct dentry *mountpoint, 104 struct file_system_type *type, 105 const char *name, void *data); 106 107 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list); 108 extern void mark_mounts_for_expiry(struct list_head *mounts); 109 110 extern dev_t name_to_dev_t(const char *name); 111 extern bool path_is_mountpoint(const struct path *path); 112 113 extern bool our_mnt(struct vfsmount *mnt); 114 115 extern struct vfsmount *kern_mount(struct file_system_type *); 116 extern void kern_unmount(struct vfsmount *mnt); 117 extern int may_umount_tree(struct vfsmount *); 118 extern int may_umount(struct vfsmount *); 119 extern long do_mount(const char *, const char __user *, 120 const char *, unsigned long, void *); 121 extern struct vfsmount *collect_mounts(const struct path *); 122 extern void drop_collected_mounts(struct vfsmount *); 123 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *, 124 struct vfsmount *); 125 extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num); 126 127 #endif /* _LINUX_MOUNT_H */ 128