[Qemu-devel] [PATCH 14/14] block-qcow2: do not keep track of highest-alloc for backing files

[Uri Lublin <uril@redhat.com>]

Signed-off-by: Uri Lublin <uril@redhat.com>
---
 block-qcow2.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/block-qcow2.c b/block-qcow2.c
index c98024e..63460e0 100644
--- a/block-qcow2.c
+++ b/block-qcow2.c
@@ -260,6 +260,8 @@ static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset,
             break;
 
         case QCOW_EXT_MAGIC_HIGH_ALLOC:
+            if ((bs->open_flags & BDRV_O_BACKING) != 0)
+                break;
             if (ext.len != sizeof(uint64_t)) {
                 fprintf(stderr, "ERROR: ext_high_alloc: len=%u too large"
                         " (>=%lu)\n",
@@ -294,6 +296,9 @@ static void update_highest_alloc(BlockDriverState *bs)
     uint64_t high;
     int ret;
 
+    if ((bs->open_flags & BDRV_O_BACKING) != 0)
+        return;
+
 #ifdef DEBUG_EXT
     QCowExtension ext;
     int len;
-- 
1.6.0.6