[Qemu-devel] [PATCH 02/13] block: Fix is_allocated_above with resized files

[Stefan Hajnoczi <stefanha@redhat.com>]

From: Vishvananda Ishaya <vishvananda@gmail.com>

In an image chain, if the base image is smaller than the current
image, we need to make sure to use the current images count of
unallocated blocks once we get to the end of the base image. Without
this change the code will return 0 blocks when it gets to the end
of the base image and mirror_run will fail its assertion.

Signed-off-by: Vishvananda Ishaya <vishvananda@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block.c b/block.c
index ba67c0d..50dab8e 100644
--- a/block.c
+++ b/block.c
@@ -2800,7 +2800,9 @@ int coroutine_fn bdrv_co_is_allocated_above(BlockDriverState *top,
          *
          * [sector_num+x, nr_sectors] allocated.
          */
-        if (n > pnum_inter) {
+        if (n > pnum_inter &&
+            (intermediate == top ||
+             sector_num + pnum_inter < intermediate->total_sectors)) {
             n = pnum_inter;
         }
 
-- 
1.8.1