If the root node of a fs/file tree is in the block group that is being relocated, but the others are not in the other block groups. when we create a snapshot for this tree between the relocation tree creation ends and ->create_reloc_tree is set to 0, Btrfs will create some backref nodes that are the lowest nodes of the backrefs cache. But we forget to add them into ->leaves list of the backref cache and deal with them, and at last, they will triggered BUG_ON(). kernel BUG at fs/btrfs/relocation.c:239! This patch fixes it by adding them into ->leaves list of backref cache. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> --- fs/btrfs/relocation.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 162af18..1db3771 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -1174,6 +1174,8 @@ static int clone_backref_node(struct btrfs_trans_handle *trans, list_add_tail(&new_edge->list[UPPER], &new_node->lower); } + } else { + list_add_tail(&new_node->lower, &cache->leaves); } rb_node = tree_insert(&cache->rb_root, new_node->bytenr, -- 1.7.6.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html