From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 18 Aug 2014 19:09:26 +0000 (-0400)
Subject: get rid of propagate_umount() mistakenly treating slaves as busy.
X-Git-Tag: v3.17-rc4~7^2~2
X-Git-Url: http://git.cascardo.info/?a=commitdiff_plain;h=88b368f27a094277143d8ecd5a056116f6a41520;p=cascardo%2Flinux.git

get rid of propagate_umount() mistakenly treating slaves as busy.

The check in __propagate_umount() ("has somebody explicitly mounted
something on that slave?") is done *before* taking the already doomed
victims out of the child lists.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/namespace.c b/fs/namespace.c
index a01c7730e9af..3273177873f0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1253,6 +1253,9 @@ void umount_tree(struct mount *mnt, int how)
 		hlist_add_head(&p->mnt_hash, &tmp_list);
 	}
 
+	hlist_for_each_entry(p, &tmp_list, mnt_hash)
+		list_del_init(&p->mnt_child);
+
 	if (how)
 		propagate_umount(&tmp_list);
 
@@ -1263,7 +1266,6 @@ void umount_tree(struct mount *mnt, int how)
 		p->mnt_ns = NULL;
 		if (how < 2)
 			p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
-		list_del_init(&p->mnt_child);
 		if (mnt_has_parent(p)) {
 			put_mountpoint(p->mnt_mp);
 			/* move the reference to mountpoint into ->mnt_ex_mountpoint */
diff --git a/fs/pnode.c b/fs/pnode.c
index 302bf22c4a30..aae331a5d03b 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -381,6 +381,7 @@ static void __propagate_umount(struct mount *mnt)
 		 * other children
 		 */
 		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);
 		}