Commit 1708cc57 authored Dec 28, 2013 by Wang Shilong Committed by Chris Mason Jan 28, 2014

Btrfs: fix an oops when we fail to relocate tree blocks



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>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

parent e77751aa

fs/btrfs/relocation.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -4009,6 +4009,12 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
		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;