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 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 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) 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 54 #define MNT_INTERNAL 0x4000 55 56 #define MNT_LOCK_ATIME 0x040000 57 #define MNT_LOCK_NOEXEC 0x080000 58 #define MNT_LOCK_NOSUID 0x100000 59 #define MNT_LOCK_NODEV 0x200000 60 #define MNT_LOCK_READONLY 0x400000 61 #define MNT_LOCKED 0x800000 62 #define MNT_DOOMED 0x1000000 63 #define MNT_SYNC_UMOUNT 0x2000000 64 #define MNT_MARKED 0x4000000 65 #define MNT_UMOUNT 0x8000000 66 67 struct vfsmount { 68 struct dentry *mnt_root; /* root of the mounted tree */ 69 struct super_block *mnt_sb; /* pointer to superblock */ 70 int mnt_flags; 71 } __randomize_layout; 72 73 struct file; /* forward dec */ 74 struct path; 75 76 extern int mnt_want_write(struct vfsmount *mnt); 77 extern int mnt_want_write_file(struct file *file); 78 extern int mnt_clone_write(struct vfsmount *mnt); 79 extern void mnt_drop_write(struct vfsmount *mnt); 80 extern void mnt_drop_write_file(struct file *file); 81 extern void mntput(struct vfsmount *mnt); 82 extern struct vfsmount *mntget(struct vfsmount *mnt); 83 extern struct vfsmount *mnt_clone_internal(const struct path *path); 84 extern int __mnt_is_readonly(struct vfsmount *mnt); 85 extern bool mnt_may_suid(struct vfsmount *mnt); 86 87 struct path; 88 extern struct vfsmount *clone_private_mount(const struct path *path); 89 90 struct file_system_type; 91 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 92 int flags, const char *name, 93 void *data); 94 extern struct vfsmount *vfs_submount(const struct dentry *mountpoint, 95 struct file_system_type *type, 96 const char *name, void *data); 97 98 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list); 99 extern void mark_mounts_for_expiry(struct list_head *mounts); 100 101 extern dev_t name_to_dev_t(const char *name); 102 103 extern unsigned int sysctl_mount_max; 104 105 extern bool path_is_mountpoint(const struct path *path); 106 107 #endif /* _LINUX_MOUNT_H */ 108
