From dfe0bb55eea9efabc98d074407e01c9a85b7497b Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Mon, 7 Jun 2010 16:43:22 +0200
Subject: [PATCH] qcow2: Restore L1 entry on l2_allocate failure

If writing the L1 table to disk failed, we need to restore its old content in
memory to avoid inconsistencies.

Reported-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 68dba0bf455e60061bb3c9c40ef0d82916372664)
---
 block/qcow2-cluster.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index b7a5b35f40e..8c67e3c07d9 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -266,6 +266,7 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
     return l2_table;
 
 fail:
+    s->l1_table[l1_index] = old_l2_offset;
     qcow2_l2_cache_reset(bs);
     return NULL;
 }
-- 
2.39.5