dcache: add missing lockdep annotation

commit 9f12600fe425bc28f0ccba034a77783c09c15af4 upstream.

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@fedoraproject.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/dcache.c b/fs/dcache.c
index 7374c578154d53fe111f99e1d63c9745a6b0191e..40d474129c1c87b5007fe478c9d3f81e4cec161b 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -551,7 +551,7 @@ 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;