[Devel] [PATCH 10/10] dcache: add missing lockdep annotation

[Vladimir Davydov]

From: Linus Torvalds <torvalds at linux-foundation.org>

lock_parent() very much on purpose does nested locking of dentries, and
is careful to maintain the right order (lock parent first).  But because
it didn't annotate the nested locking order, lockdep thought it might be
a deadlock on d_lock, and complained.

Add the proper annotation for the inner locking of the child dentry to
make lockdep happy.

Introduced by commit 046b961b45f9 ("shrink_dentry_list(): take parent's
->d_lock earlier").

Reported-and-tested-by: Josh Boyer <jwboyer at fedoraproject.org>
Cc: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
(cherry picked from commit 9f12600fe425bc28f0ccba034a77783c09c15af4)
Signed-off-by: Vladimir Davydov <vdavydov at virtuozzo.com>
---
 fs/dcache.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index ab6859764a6a..09ed486c9f1d 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -582,7 +582,7 @@ again:
 	}
 	rcu_read_unlock();
 	if (parent != dentry)
-		spin_lock(&dentry->d_lock);
+		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
 	else
 		parent = NULL;
 	return parent;
-- 
2.1.4