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 <linux/list.h> 15 #include <linux/nodemask.h> 16 #include <linux/spinlock.h> 17 #include <linux/seqlock.h> 18 #include <linux/atomic.h> 19 20 struct super_block; 21 struct vfsmount; 22 struct dentry; 23 struct mnt_namespace; 24 struct fs_context; 25 26 #define MNT_NOSUID 0x01 27 #define MNT_NODEV 0x02 28 #define MNT_NOEXEC 0x04 29 #define MNT_NOATIME 0x08 30 #define MNT_NODIRATIME 0x10 31 #define MNT_RELATIME 0x20 32 #define MNT_READONLY 0x40 /* does the user want this to be r/o? */ 33 #define MNT_NOSYMFOLLOW 0x80 34 35 #define MNT_SHRINKABLE 0x100 36 #define MNT_WRITE_HOLD 0x200 37 38 #define MNT_SHARED 0x1000 /* if the vfsmount is a shared mount */ 39 #define MNT_UNBINDABLE 0x2000 /* if the vfsmount is a unbindable mount */ 40 /* 41 * MNT_SHARED_MASK is the set of flags that should be cleared when a 42 * mount becomes shared. Currently, this is only the flag that says a 43 * mount cannot be bind mounted, since this is how we create a mount 44 * that shares events with another mount. If you add a new MNT_* 45 * flag, consider how it interacts with shared mounts. 46 */ 47 #define MNT_SHARED_MASK (MNT_UNBINDABLE) 48 #define MNT_USER_SETTABLE_MASK (MNT_NOSUID | MNT_NODEV | MNT_NOEXEC \ 49 | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME \ 50 | MNT_READONLY | MNT_NOSYMFOLLOW) 51 #define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME ) 52 53 #define MNT_INTERNAL_FLAGS (MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL | \ 54 MNT_DOOMED | MNT_SYNC_UMOUNT | MNT_MARKED | \ 55 MNT_CURSOR) 56 57 #define MNT_INTERNAL 0x4000 58 59 #define MNT_LOCK_ATIME 0x040000 60 #define MNT_LOCK_NOEXEC 0x080000 61 #define MNT_LOCK_NOSUID 0x100000 62 #define MNT_LOCK_NODEV 0x200000 63 #define MNT_LOCK_READONLY 0x400000 64 #define MNT_LOCKED 0x800000 65 #define MNT_DOOMED 0x1000000 66 #define MNT_SYNC_UMOUNT 0x2000000 67 #define MNT_MARKED 0x4000000 68 #define MNT_UMOUNT 0x8000000 69 #define MNT_CURSOR 0x10000000 70 71 struct vfsmount { 72 struct dentry *mnt_root; /* root of the mounted tree */ 73 struct super_block *mnt_sb; /* pointer to superblock */ 74 int mnt_flags; 75 struct user_namespace *mnt_userns; 76 } __randomize_layout; 77 78 static inline struct user_namespace *mnt_user_ns(const struct vfsmount *mnt) 79 { 80 /* Pairs with smp_store_release() in do_idmap_mount(). */ 81 return smp_load_acquire(&mnt->mnt_userns); 82 } 83 84 struct file; /* forward dec */ 85 struct path; 86 87 extern int mnt_want_write(struct vfsmount *mnt); 88 extern int mnt_want_write_file(struct file *file); 89 extern void mnt_drop_write(struct vfsmount *mnt); 90 extern void mnt_drop_write_file(struct file *file); 91 extern void mntput(struct vfsmount *mnt); 92 extern struct vfsmount *mntget(struct vfsmount *mnt); 93 extern struct vfsmount *mnt_clone_internal(const struct path *path); 94 extern bool __mnt_is_readonly(struct vfsmount *mnt); 95 extern bool mnt_may_suid(struct vfsmount *mnt); 96 97 struct path; 98 extern struct vfsmount *clone_private_mount(const struct path *path); 99 extern int __mnt_want_write(struct vfsmount *); 100 extern void __mnt_drop_write(struct vfsmount *); 101 102 struct file_system_type; 103 extern struct vfsmount *fc_mount(struct fs_context *fc); 104 extern struct vfsmount *vfs_create_mount(struct fs_context *fc); 105 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 106 int flags, const char *name, 107 void *data); 108 extern struct vfsmount *vfs_submount(const struct dentry *mountpoint, 109 struct file_system_type *type, 110 const char *name, void *data); 111 112 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list); 113 extern void mark_mounts_for_expiry(struct list_head *mounts); 114 115 extern dev_t name_to_dev_t(const char *name); 116 extern bool path_is_mountpoint(const struct path *path); 117 118 extern void kern_unmount_array(struct vfsmount *mnt[], unsigned int num); 119 120 #endif /* _LINUX_MOUNT_H */ 121