autofs4 - fix lockdep splat in autofs

When recursing down the locks when traversing a tree/list in
get_next_positive_dentry() or get_next_positive_subdir() a lock can
change from being nested to being a parent which breaks lockdep. This
patch tells lockdep about what we did.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index 450f529a4eae..1feb68ecef95 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -124,6 +124,7 @@ start:
         /* Negative dentry - try next */
         if (!simple_positive(q)) {
                 spin_unlock(&p->d_lock);
+                lock_set_subclass(&q->d_lock.dep_map, 0, _RET_IP_);
                 p = q;
                 goto again;
         }
@@ -186,6 +187,7 @@ again:
         /* Negative dentry - try next */
         if (!simple_positive(ret)) {
                 spin_unlock(&p->d_lock);
+                lock_set_subclass(&ret->d_lock.dep_map, 0, _RET_IP_);
                 p = ret;
                 goto again;
         }