9 #include <linux/mount.h>
12 #include <uapi/linux/mount.h>
16 /* return the next shared peer mount of @p */
17 static inline struct mount *next_peer(struct mount *p)  in next_peer()
19 	return list_entry(p->mnt_share.next, struct mount, mnt_share);  in next_peer()
22 static inline struct mount *first_slave(struct mount *p)  in first_slave()
24 	return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave);  in first_slave()
27 static inline struct mount *last_slave(struct mount *p)  in last_slave()
29 	return list_entry(p->mnt_slave_list.prev, struct mount, mnt_slave);  in last_slave()
32 static inline struct mount *next_slave(struct mount *p)  in next_slave()
34 	return list_entry(p->mnt_slave.next, struct mount, mnt_slave);  in next_slave()
37 static struct mount *get_peer_under_root(struct mount *mnt,  in get_peer_under_root()
41 	struct mount *m = mnt;  in get_peer_under_root()
60 int get_dominating_id(struct mount *mnt, const struct path *root)  in get_dominating_id()
62 	struct mount *m;  in get_dominating_id()
65 		struct mount *d = get_peer_under_root(m, mnt->mnt_ns, root);  in get_dominating_id()
73 static int do_make_slave(struct mount *mnt)  in do_make_slave()
75 	struct mount *master, *slave_mnt;  in do_make_slave()
87 						struct mount, mnt_slave);  in do_make_slave()
94 		struct mount *m;  in do_make_slave()
96 		 * slave 'mnt' to a peer mount that has the  in do_make_slave()
122 void change_mnt_propagation(struct mount *mnt, int type)  in change_mnt_propagation()
140  * get the next mount in the propagation tree.
141  * @m: the mount seen last
142  * @origin: the original mount from where the tree walk initiated
149 static struct mount *propagation_next(struct mount *m,  in propagation_next()
150 					 struct mount *origin)  in propagation_next()
152 	/* are there any slaves of this mount? */  in propagation_next()
157 		struct mount *master = m->mnt_master;  in propagation_next()
160 			struct mount *next = next_peer(m);  in propagation_next()
170 static struct mount *skip_propagation_subtree(struct mount *m,  in skip_propagation_subtree()
171 						struct mount *origin)  in skip_propagation_subtree()
183 static struct mount *next_group(struct mount *m, struct mount *origin)  in next_group()
187 			struct mount *next;  in next_group()
200 			struct mount *master = m->mnt_master;  in next_group()
216 static struct mount *last_dest, *first_source, *last_source, *dest_master;
219 static inline bool peers(const struct mount *m1, const struct mount *m2)  in peers()
224 static int propagate_one(struct mount *m, struct mountpoint *dest_mp)  in propagate_one()
226 	struct mount *child;  in propagate_one()
241 		struct mount *n, *p;  in propagate_one()
249 			struct mount *parent = last_source->mnt_parent;  in propagate_one()
279  * mount 'source_mnt' under the destination 'dest_mnt' at
280  * dentry 'dest_dentry'. And propagate that mount to
286  * @dest_mnt: destination mount.
288  * @source_mnt: source mount.
291 int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,  in propagate_mnt()
292 		    struct mount *source_mnt, struct hlist_head *tree_list)  in propagate_mnt()
294 	struct mount *m, *n;  in propagate_mnt()
338 static struct mount *find_topper(struct mount *mnt)  in find_topper()
340 	/* If there is exactly one mount covering mnt completely return it. */  in find_topper()
341 	struct mount *child;  in find_topper()
346 	child = list_first_entry(&mnt->mnt_mounts, struct mount, mnt_child);  in find_topper()
356 static inline int do_refcount_check(struct mount *mnt, int count)  in do_refcount_check()
364  * @from: shared mount
365  * @to:   mount to check
372  * If the root of the @to mount is equal to the future mountpoint @mp of
373  * the @to mount on @from then @to will be overmounted by whatever is
380 bool propagation_would_overmount(const struct mount *from,  in propagation_would_overmount()
381 				 const struct mount *to,  in propagation_would_overmount()
390 	for (const struct mount *m = to; m; m = m->mnt_master) {  in propagation_would_overmount()
399  * check if the mount 'mnt' can be unmounted successfully.
400  * @mnt: the mount to be checked for unmount
408 int propagate_mount_busy(struct mount *mnt, int refcnt)  in propagate_mount_busy()
410 	struct mount *m, *child, *topper;  in propagate_mount_busy()
411 	struct mount *parent = mnt->mnt_parent;  in propagate_mount_busy()
417 	 * quickly check if the current mount can be unmounted.  in propagate_mount_busy()
431 		/* Is there exactly one mount on the child that covers  in propagate_mount_busy()
451 void propagate_mount_unlock(struct mount *mnt)  in propagate_mount_unlock()
453 	struct mount *parent = mnt->mnt_parent;  in propagate_mount_unlock()
454 	struct mount *m, *child;  in propagate_mount_unlock()
466 static void umount_one(struct mount *mnt, struct list_head *to_umount)  in umount_one()
479 static bool __propagate_umount(struct mount *mnt,  in __propagate_umount()
484 	struct mount *child;  in __propagate_umount()
487 	 * The state of the parent won't change if this mount is  in __propagate_umount()
509 	/* If a mount is without children and not locked umount it. */  in __propagate_umount()
523 	struct mount *mnt, *child, *tmp;  in umount_list()
539 		struct mount *mnt, *parent;  in restore_mounts()
542 		mnt = list_first_entry(to_restore, struct mount, mnt_umounting);  in restore_mounts()
546 		/* Should this mount be reparented? */  in restore_mounts()
563 		struct mount *mnt =  in cleanup_umount_visitations()
564 			list_first_entry(visited, struct mount, mnt_umounting);  in cleanup_umount_visitations()
570  * collect all mounts that receive propagation from the mount in @list,
578 	struct mount *mnt;  in propagate_umount()
585 		struct mount *parent = mnt->mnt_parent;  in propagate_umount()
586 		struct mount *m;  in propagate_umount()
589 		 * If this mount has already been visited it is known that it's  in propagate_umount()
600 			struct mount *child = __lookup_mnt(&m->mnt,  in propagate_umount()
618 				 * mount in a list that has not been visited  in propagate_umount()