tools/qemu/patches/0003-VMDK-bugfix-align-offset-to-cluster-in-get_whole_clu.patch

   1 From 66922efc83a670178b208dec2f5123ec85fb6ba3 Mon Sep 17 00:00:00 2001
   2 From: Fam Zheng <famcool@gmail.com>
   3 Date: Tue, 12 Jul 2011 19:56:29 +0800
   4 Subject: [PATCH 03/12] VMDK: bugfix, align offset to cluster in
   5  get_whole_cluster
   6
   7 In get_whole_cluster, the offset is not aligned to cluster when reading
   8 from backing_hd. When the first write to child is not at the cluster
   9 boundary, wrong address data from parent is copied to child.
  10
  11 Signed-off-by: Fam Zheng <famcool@gmail.com>
  12 Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
  13 Signed-off-by: Kevin Wolf <kwolf@redhat.com>
  14 ---
  15  block/vmdk.c | 8 +++++---
  16  1 file changed, 5 insertions(+), 3 deletions(-)
  17
  18 --- a/block/vmdk.c
  19 +++ b/block/vmdk.c
  20 @@ -514,21 +514,23 @@ static int get_whole_cluster(BlockDriver
  21      /* 128 sectors * 512 bytes each = grain size 64KB */
  22      uint8_t  whole_grain[extent->cluster_sectors * 512];
  23
  24 -    // we will be here if it's first write on non-exist grain(cluster).
  25 -    // try to read from parent image, if exist
  26 +    /* we will be here if it's first write on non-exist grain(cluster).
  27 +     * try to read from parent image, if exist */
  28      if (bs->backing_hd) {
  29          int ret;
  30
  31          if (!vmdk_is_cid_valid(bs))
  32              return -1;
  33
  34 +        /* floor offset to cluster */
  35 +        offset -= offset % (extent->cluster_sectors * 512);
  36          ret = bdrv_read(bs->backing_hd, offset >> 9, whole_grain,
  37                  extent->cluster_sectors);
  38          if (ret < 0) {
  39              return -1;
  40          }
  41
  42 -        //Write grain only into the active image
  43 +        /* Write grain only into the active image */
  44          ret = bdrv_write(extent->file, cluster_offset, whole_grain,
  45                  extent->cluster_sectors);
  46          if (ret < 0) {