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 #include <linux/android_kabi.h> 20 21 struct super_block; 22 struct vfsmount; 23 struct dentry; 24 struct mnt_namespace; 25 struct fs_context; 26 27 #define MNT_NOSUID 0x01 28 #define MNT_NODEV 0x02 29 #define MNT_NOEXEC 0x04 30 #define MNT_NOATIME 0x08 31 #define MNT_NODIRATIME 0x10 32 #define MNT_RELATIME 0x20 33 #define MNT_READONLY 0x40 /* does the user want this to be r/o? */ 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) 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 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 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 ANDROID_KABI_RESERVE(1); 74 ANDROID_KABI_RESERVE(2); 75 ANDROID_KABI_RESERVE(3); 76 ANDROID_KABI_RESERVE(4); 77 void *data; 78 } __randomize_layout; 79 80 struct file; /* forward dec */ 81 struct path; 82 83 extern int mnt_want_write(struct vfsmount *mnt); 84 extern int mnt_want_write_file(struct file *file); 85 extern int mnt_clone_write(struct vfsmount *mnt); 86 extern void mnt_drop_write(struct vfsmount *mnt); 87 extern void mnt_drop_write_file(struct file *file); 88 extern void mntput(struct vfsmount *mnt); 89 extern struct vfsmount *mntget(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 struct path; 95 extern struct vfsmount *clone_private_mount(const struct path *path); 96 extern int __mnt_want_write(struct vfsmount *); 97 extern void __mnt_drop_write(struct vfsmount *); 98 99 struct file_system_type; 100 extern struct vfsmount *fc_mount(struct fs_context *fc); 101 extern struct vfsmount *vfs_create_mount(struct fs_context *fc); 102 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type, 103 int flags, const char *name, 104 void *data); 105 extern struct vfsmount *vfs_submount(const struct dentry *mountpoint, 106 struct file_system_type *type, 107 const char *name, void *data); 108 109 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list); 110 extern void mark_mounts_for_expiry(struct list_head *mounts); 111 112 extern dev_t name_to_dev_t(const char *name); 113 114 extern unsigned int sysctl_mount_max; 115 116 extern bool path_is_mountpoint(const struct path *path); 117 118 #endif /* _LINUX_MOUNT_H */ 119