Commit c003b26f authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

mnt: In umount_tree reuse mnt_list instead of mnt_hash 



umount_tree builds a list of mounts that need to be unmounted.
Utilize mnt_list for this purpose instead of mnt_hash.  This begins to
allow keeping a mount on the mnt_hash after it is unmounted, which is
necessary for a properly functioning MNT_LOCKED implementation.

The fact that mnt_list is an ordinary list makding available list_move
is nice bonus.

Cc: stable@vger.kernel.org
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 8318e667

fs/namespace.c

+11 −9
Original line number Diff line number Diff line
@@ -1327,23 +1327,25 @@ enum umount_tree_flags { 
 */

static void umount_tree(struct mount *mnt, enum umount_tree_flags how)

{

	HLIST_HEAD(tmp_list);

	LIST_HEAD(tmp_list);

	struct mount *p;



	for (p = mnt; p; p = next_mnt(p, mnt)) {

		hlist_del_init_rcu(&p->mnt_hash);

		hlist_add_head(&p->mnt_hash, &tmp_list);

	}

	/* Gather the mounts to umount */

	for (p = mnt; p; p = next_mnt(p, mnt))

		list_move(&p->mnt_list, &tmp_list);



	hlist_for_each_entry(p, &tmp_list, mnt_hash)

	/* Hide the mounts from lookup_mnt and mnt_mounts */

	list_for_each_entry(p, &tmp_list, mnt_list) {

		hlist_del_init_rcu(&p->mnt_hash);

		list_del_init(&p->mnt_child);

	}



	/* Add propogated mounts to the tmp_list */

	if (how & UMOUNT_PROPAGATE)

		propagate_umount(&tmp_list);



	while (!hlist_empty(&tmp_list)) {

		p = hlist_entry(tmp_list.first, struct mount, mnt_hash);

		hlist_del_init_rcu(&p->mnt_hash);

	while (!list_empty(&tmp_list)) {

		p = list_first_entry(&tmp_list, struct mount, mnt_list);

		list_del_init(&p->mnt_expire);

		list_del_init(&p->mnt_list);

		__touch_mnt_namespace(p->mnt_ns);

fs/pnode.c

+3 −3
Original line number Diff line number Diff line
@@ -384,7 +384,7 @@ static void __propagate_umount(struct mount *mnt) 
		if (child && list_empty(&child->mnt_mounts)) {

			list_del_init(&child->mnt_child);

			hlist_del_init_rcu(&child->mnt_hash);

			hlist_add_before_rcu(&child->mnt_hash, &mnt->mnt_hash);

			list_move_tail(&child->mnt_list, &mnt->mnt_list);

		}

	}

}
@@ -396,11 +396,11 @@ static void __propagate_umount(struct mount *mnt) 
 *

 * vfsmount lock must be held for write

 */

int propagate_umount(struct hlist_head *list)

int propagate_umount(struct list_head *list)

{

	struct mount *mnt;



	hlist_for_each_entry(mnt, list, mnt_hash)

	list_for_each_entry(mnt, list, mnt_list)

		__propagate_umount(mnt);

	return 0;

}

fs/pnode.h

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ static inline void set_mnt_shared(struct mount *mnt) 
void change_mnt_propagation(struct mount *, int);

int propagate_mnt(struct mount *, struct mountpoint *, struct mount *,

		struct hlist_head *);

int propagate_umount(struct hlist_head *);

int propagate_umount(struct list_head *);

int propagate_mount_busy(struct mount *, int);

void mnt_release_group_id(struct mount *);

int get_dominating_id(struct mount *mnt, const struct path *root);

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