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VMDK: bugfix, align offset to cluster in get_whole_cluster 

In get_whole_cluster, the offset is not aligned to cluster when reading
from backing_hd. When the first write to child is not at the cluster
boundary, wrong address data from parent is copied to child.

Signed-off-by: Fam Zheng <famcool@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Fam Zheng 2011-07-12 19:56:29 +08:00 committed by Kevin Wolf
parent b3976d3c8b
commit 0e69c54394
1 changed files with 5 additions and 3 deletions
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8
block/vmdk.c
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@ -514,21 +514,23 @@ static int get_whole_cluster(BlockDriverState *bs,
/* 128 sectors * 512 bytes each = grain size 64KB */ /* 128 sectors * 512 bytes each = grain size 64KB */
uint8_t whole_grain[extent->cluster_sectors * 512]; uint8_t whole_grain[extent->cluster_sectors * 512];
// we will be here if it's first write on non-exist grain(cluster). /* we will be here if it's first write on non-exist grain(cluster).
// try to read from parent image, if exist * try to read from parent image, if exist */
if (bs->backing_hd) { if (bs->backing_hd) {
int ret; int ret;
if (!vmdk_is_cid_valid(bs)) if (!vmdk_is_cid_valid(bs))
return -1; return -1;
/* floor offset to cluster */
offset -= offset % (extent->cluster_sectors * 512);
ret = bdrv_read(bs->backing_hd, offset >> 9, whole_grain, ret = bdrv_read(bs->backing_hd, offset >> 9, whole_grain,
extent->cluster_sectors); extent->cluster_sectors);
if (ret < 0) { if (ret < 0) {
return -1; return -1;
} }
//Write grain only into the active image /* Write grain only into the active image */
ret = bdrv_write(extent->file, cluster_offset, whole_grain, ret = bdrv_write(extent->file, cluster_offset, whole_grain,
extent->cluster_sectors); extent->cluster_sectors);
if (ret < 0) { if (ret < 0) {