commit 4ec6c2aeab8a909418ac60b782a963cb7257207f
author Li Zhong <zhong@linux.vnet.ibm.com> Wed Nov 13 15:21:51 2013 +0800
committer Al Viro <viro@zeniv.linux.org.uk> Wed Nov 13 07:43:10 2013 -0500
tree 9f9f780852ed4c5a5cce6c2e84cbfceb1c12fd5f
parent 4fdb793ffe262cfc0b796d3b2cd05ca3b687deb9

fix unpaired rcu lock in prepend_path()

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c

diff --git a/fs/dcache.c b/fs/dcache.c
index 1f24cd6..eacc853 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2924,6 +2924,7 @@
 restart_mnt:
 	read_seqbegin_or_lock(&mount_lock, &m_seq);
 	seq = 0;
+	rcu_read_lock();
 restart:
 	bptr = *buffer;
 	blen = *buflen;
@@ -2971,6 +2972,9 @@
 		goto restart;
 	}
 	done_seqretry(&rename_lock, seq);
+
+	if (!(m_seq & 1))
+		rcu_read_unlock();
 	if (need_seqretry(&mount_lock, m_seq)) {
 		m_seq = 1;
 		goto restart_mnt;