d_walk() might skip too much

when we find that a child has died while we'd been trying to ascend,
we should go into the first live sibling itself, rather than its sibling.

Off-by-one in question had been introduced in "deal with deadlock in
d_walk()" and the fix needs to be backported to all branches this one
has been backported to.

Cc: stable@vger.kernel.org # 3.2 and later
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-05-28 23:09:19 -04:00
parent 030bbdbf4c
commit 2159184ea0

View File

@ -1239,13 +1239,13 @@ static void d_walk(struct dentry *parent, void *data,
/* might go back up the wrong parent if we have had a rename. */
if (need_seqretry(&rename_lock, seq))
goto rename_retry;
next = child->d_child.next;
while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)) {
/* go into the first sibling still alive */
do {
next = child->d_child.next;
if (next == &this_parent->d_subdirs)
goto ascend;
child = list_entry(next, struct dentry, d_child);
next = next->next;
}
} while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
rcu_read_unlock();
goto resume;
}