From 3bb8b653c86f6b1d2cc05aa1744fed4b18f99485 Mon Sep 17 00:00:00 2001
From: Joseph Qi
Date: Mon, 19 Sep 2016 14:44:33 -0700
Subject: ocfs2: fix double unlock in case retry after free truncate log

If ocfs2_reserve_cluster_bitmap_bits() fails with ENOSPC, it will try to
free truncate log and then retry.  Since ocfs2_try_to_free_truncate_log
will lock/unlock global bitmap inode, we have to unlock it before
calling this function.  But when retry reserve and it fails with no
global bitmap inode lock taken, it will unlock again in error handling
branch and BUG.

This issue also exists if no need retry and then ocfs2_inode_lock fails.
So fix it.

Fixes: 2070ad1aebff ("ocfs2: retry on ENOSPC if sufficient space in truncate log")
Link: http://lkml.kernel.org/r/57D91939.6030809@huawei.com
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Jiufei Xue <xuejiufei@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/ocfs2/suballoc.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index ea47120a85ff..6ad3533940ba 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1199,14 +1199,24 @@ retry:
 			inode_unlock((*ac)->ac_inode);
 
 			ret = ocfs2_try_to_free_truncate_log(osb, bits_wanted);
-			if (ret == 1)
+			if (ret == 1) {
+				iput((*ac)->ac_inode);
+				(*ac)->ac_inode = NULL;
 				goto retry;
+			}
 
 			if (ret < 0)
 				mlog_errno(ret);
 
 			inode_lock((*ac)->ac_inode);
-			ocfs2_inode_lock((*ac)->ac_inode, NULL, 1);
+			ret = ocfs2_inode_lock((*ac)->ac_inode, NULL, 1);
+			if (ret < 0) {
+				mlog_errno(ret);
+				inode_unlock((*ac)->ac_inode);
+				iput((*ac)->ac_inode);
+				(*ac)->ac_inode = NULL;
+				goto bail;
+			}
 		}
 		if (status < 0) {
 			if (status != -ENOSPC)
-- 
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