From: Liu Bo <bo.li.liu@oracle.com>
Date: Thu, 25 Jan 2018 18:02:50 +0000 (-0700)
Subject: Btrfs: fix deadlock in run_delalloc_nocow
X-Git-Tag: v4.9.83~58
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ecd72fd604b1f3aa3ec03962e4676760a8e1a1b4;p=platform%2Fkernel%2Flinux-amlogic.git

Btrfs: fix deadlock in run_delalloc_nocow

commit e89166990f11c3f21e1649d760dd35f9e410321c upstream.

@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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a8a1fb40e258..c3d413494779 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1320,8 +1320,11 @@ 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];