From 7b8a53fd815deb39542085897743fa0063f9fe06 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 15 Jan 2011 20:08:44 -0500 Subject: [PATCH] fix old umount_tree() breakage Expiry-related code calls umount_tree() several times with the same list to collect vfsmounts to. Which is fine, except that umount_tree() implicitly assumed that the list would be empty on each call - it moves the victims over there and then iterates through the list kicking them out. It's *almost* idempotent, so everything nearly worked. However, mnt->ghosts handling (and thus expirability checks) had been broken - that part was not idempotent... The fix is trivial - use local temporary list, splice it to the the collector list when we are through. Signed-off-by: Al Viro --- fs/namespace.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index bfcb701f9490..d7fc05fac753 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1226,15 +1226,16 @@ void release_mounts(struct list_head *head) */ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) { + LIST_HEAD(tmp_list); struct vfsmount *p; for (p = mnt; p; p = next_mnt(p, mnt)) - list_move(&p->mnt_hash, kill); + list_move(&p->mnt_hash, &tmp_list); if (propagate) - propagate_umount(kill); + propagate_umount(&tmp_list); - list_for_each_entry(p, kill, mnt_hash) { + list_for_each_entry(p, &tmp_list, mnt_hash) { list_del_init(&p->mnt_expire); list_del_init(&p->mnt_list); __touch_mnt_namespace(p->mnt_ns); @@ -1246,6 +1247,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) } change_mnt_propagation(p, MS_PRIVATE); } + list_splice(&tmp_list, kill); } static void shrink_submounts(struct vfsmount *mnt, struct list_head *umounts); -- GitLab