commit bec324f33d1ed346394b2eee25bf6dbf3511f727 upstream.
When the parent directory's i_rwsem is not locked, req->r_parent may become
stale due to concurrent operations (e.g. rename) between dentry lookup and
message creation. Validate that r_parent matches the encoded parent inode
and update to the correct inode if a mismatch is detected.
[ idryomov: folded a follow-up fix from Alex to drop extra reference
from ceph_get_reply_dir() in ceph_fill_trace():
ceph_get_reply_dir() may return a different, referenced inode when
r_parent is stale and the parent directory lock is not held.
ceph_fill_trace() used that inode but failed to drop the reference
when it differed from req->r_parent, leaking an inode reference.
Keep the directory inode in a local variable and iput() it at
function end if it does not match req->r_parent. ]
Cc: stable@vger.kernel.org
Signed-off-by: Alex Markuze <amarkuze@redhat.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
305935130d