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 file_system_type; 20 struct fs_context; 21 struct file; 22 struct 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 69 struct 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 76 static 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 82 extern int mnt_want_write(struct vfsmount *mnt); 83 extern int mnt_want_write_file(struct file *file); 84 extern void mnt_drop_write(struct vfsmount *mnt); 85 extern void mnt_drop_write_file(struct file *file); 86 extern void mntput(struct vfsmount *mnt); 87 extern struct vfsmount *mntget(struct vfsmount *mnt); 88 extern struct vfsmount *mnt_clone_internal(const struct path *path); 89 extern bool __mnt_is_readonly(struct vfsmount *mnt); 90 extern bool mnt_may_suid(struct vfsmount *mnt); 91 92 extern struct vfsmount *clone_private_mount(const struct path *path); 93 extern int __mnt_want_write(struct vfsmount *); 94 extern void __mnt_drop_write(struct vfsmount *); 95 96 extern struct vfsmount *fc_mount(struct fs_context *fc); 97 extern struct vfsmount *vfs_create_mount(struct fs_context *fc); 98 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 99 int flags, const char *name, 100 void *data); 101 extern struct vfsmount *vfs_submount(const struct dentry *mountpoint, 102 struct file_system_type *type, 103 const char *name, void *data); 104 105 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list); 106 extern void mark_mounts_for_expiry(struct list_head *mounts); 107 108 extern dev_t name_to_dev_t(const char *name); 109 extern bool path_is_mountpoint(const struct path *path); 110 111 extern bool our_mnt(struct vfsmount *mnt); 112 113 extern struct vfsmount *kern_mount(struct file_system_type *); 114 extern void kern_unmount(struct vfsmount *mnt); 115 extern int may_umount_tree(struct vfsmount *); 116 extern int may_umount(struct vfsmount *); 117 extern long do_mount(const char *, const char __user *, 118 const char *, unsigned long, void *); 119 extern struct vfsmount *collect_mounts(const struct path *); 120 extern void drop_collected_mounts(struct vfsmount *); 121 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *, 122 struct vfsmount *); 123 extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num); 124 125 #endif /* _LINUX_MOUNT_H */ 126