Wang Shilong
2013-Dec-28 11:52 UTC
[PATCH] Btrfs: fix an oops when we fail to relocate tree blocks
From: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
During balance test, we hit an oops:
[ 2013.841551] kernel BUG at fs/btrfs/relocation.c:1174!
The problem is that if we fail to relocate tree blocks, we should
update backref cache, otherwise, some pending nodes are not updated
while snapshot check @cache->last_trans is within one transaction
and won't update it and then oops happen.
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
---
fs/btrfs/relocation.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index b530ed9..4a3f0d9 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -4075,6 +4075,12 @@ restart:
if (!RB_EMPTY_ROOT(&blocks)) {
ret = relocate_tree_blocks(trans, rc, &blocks);
if (ret < 0) {
+ /*
+ * if we fail to relocate tree blocks, force to update
+ * backref cache when committing transaction.
+ */
+ rc->backref_cache.last_trans = trans->transid - 1;
+
if (ret != -EAGAIN) {
err = ret;
break;
--
1.8.4
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