From: Yan Zheng <zheng.yan@oracle.com>
Date: Wed, 21 Jan 2009 15:49:16 +0000 (-0500)
Subject: Btrfs: Fix infinite loop in btrfs_extent_post_op
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=5a7be515b1f4569aac601170fc681741434cca92;p=openwrt%2Fstaging%2Fblogic.git

Btrfs: Fix infinite loop in btrfs_extent_post_op

btrfs_extent_post_op calls finish_current_insert and del_pending_extents. They
both may enter infinite loops.

finish_current_insert enters infinite loop if it only finds some backrefs to
update.  The fix is to check for pending backref updates before restarting the
loop.

The infinite loop in del_pending_extents is due to a the skipped variable
not being properly reset before looping around.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
---

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3bed6a7e4b22..aeaec84ebed8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2156,7 +2156,8 @@ again:
 		ret = find_first_extent_bit(&info->extent_ins, search, &start,
 					    &end, EXTENT_WRITEBACK);
 		if (ret) {
-			if (skipped && all && !num_inserts) {
+			if (skipped && all && !num_inserts &&
+			    list_empty(&update_list)) {
 				skipped = 0;
 				search = 0;
 				continue;
@@ -2544,6 +2545,7 @@ again:
 		if (ret) {
 			if (all && skipped && !nr) {
 				search = 0;
+				skipped = 0;
 				continue;
 			}
 			mutex_unlock(&info->extent_ins_mutex);