From 7322afe7eaa7211285a38ccfb754a0a52911e394 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Wed, 20 Jan 2010 15:03:05 +0100
Subject: [PATCH] qcow2: Allow updating no refcounts
There's absolutely no problem with updating the refcounts of 0 clusters.
At least snapshot code is doing this and would fail once the result of
update_refcount isn't ignored any more.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
block/qcow2-refcount.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index a84620ffe2..da7d3f2401 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -284,8 +284,12 @@ static int update_refcount(BlockDriverState *bs,
printf("update_refcount: offset=%" PRId64 " size=%" PRId64 " addend=%d\n",
offset, length, addend);
#endif
- if (length <= 0)
+ if (length < 0) {
return -EINVAL;
+ } else if (length == 0) {
+ return 0;
+ }
+
start = offset & ~(s->cluster_size - 1);
last = (offset + length - 1) & ~(s->cluster_size - 1);
for(cluster_offset = start; cluster_offset <= last;
--
2.30.2