[PATCH 3.4 115/146] d_walk() might skip too much

lizf
2015-09-15T09:11:52Z

From: Al Viro <viro@zeniv.linux.org.uk>

3.4.109-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 2159184ea01e4ae7d15f2017e296d4bc82d5aeb0 upstream.

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.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
fs/dcache.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 8038a78..d071ea7 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1204,13 +1204,13 @@ ascend:
/* might go back up the wrong parent if we have had a rename */
if (!locked && read_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;
}
--
1.9.1