Merge remote-tracking branch 'kwolf/for-anthony' into staging

# By Kevin Wolf (16) and Stefan Hajnoczi (4)
# Via Kevin Wolf
* kwolf/for-anthony:
  qemu-iotests: add 053 unaligned compressed image size test
  block: Allow overriding backing.file.filename
  block: Remove filename parameter from .bdrv_file_open()
  vvfat: Use bdrv_open options instead of filename
  sheepdog: Use bdrv_open options instead of filename
  rbd: Use bdrv_open options instead of filename
  iscsi: Use bdrv_open options instead of filename
  gluster: Use bdrv_open options instead of filename
  curl: Use bdrv_open options instead of filename
  blkverify: Use bdrv_open options instead of filename
  blkdebug: Use bdrv_open options instead of filename
  raw-win32: Use bdrv_open options instead of filename
  raw-posix: Use bdrv_open options instead of filename
  block: Enable filename option
  block: Add driver-specific options for backing files
  block: Fail gracefully when using a format driver on protocol level
  qemu-iotests: Fix _filter_qemu
  qemu-img: do not zero-pad the compressed write buffer
  qcow: allow sub-cluster compressed write to last cluster
  qcow2: allow sub-cluster compressed write to last cluster

Message-id: 1366630294-18984-1-git-send-email-kwolf@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 15 insertions, 2 deletions

diff --git a/block/qcow2.c b/block/qcow2.c
index e8934de185..2e346d8c42 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1537,8 +1537,21 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
         return 0;
     }
 
-    if (nb_sectors != s->cluster_sectors)
-        return -EINVAL;
+    if (nb_sectors != s->cluster_sectors) {
+        ret = -EINVAL;
+
+        /* Zero-pad last write if image size is not cluster aligned */
+        if (sector_num + nb_sectors == bs->total_sectors &&
+            nb_sectors < s->cluster_sectors) {
+            uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
+            memset(pad_buf, 0, s->cluster_size);
+            memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
+            ret = qcow2_write_compressed(bs, sector_num,
+                                         pad_buf, s->cluster_sectors);
+            qemu_vfree(pad_buf);
+        }
+        return ret;
+    }
 
     out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);