From 9ba95b32566a8eac13233bfb4d116a857b9e5790 Mon Sep 17 00:00:00 2001
From: Liu Bo <bo.li.liu@oracle.com>
Date: Thu, 25 Jan 2018 11:02:50 -0700
Subject: Btrfs: fix deadlock in run_delalloc_nocow

[ Upstream commit e89166990f11c3f21e1649d760dd35f9e410321c ]

@cur_offset is not set back to what it should be (@cow_start) if
btrfs_next_leaf() returns something wrong, and the range [cow_start,
cur_offset) remains locked forever.

cc: <stable@vger.kernel.org>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 fs/btrfs/inode.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'fs')

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 1423231c7e49..884e90e9622a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1282,8 +1282,11 @@ next_slot:
 		leaf = path->nodes[0];
 		if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 			ret = btrfs_next_leaf(root, path);
-			if (ret < 0)
+			if (ret < 0) {
+				if (cow_start != (u64)-1)
+					cur_offset = cow_start;
 				goto error;
+			}
 			if (ret > 0)
 				break;
 			leaf = path->nodes[0];
-- 
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