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authorKevin Wolf <kwolf@redhat.com>2019-04-15 17:54:50 +0200
committerKevin Wolf <kwolf@redhat.com>2019-04-16 16:23:24 +0200
commit93e32b3e2012a668e4da1c2566d2935c24060435 (patch)
treec86b9fbe0dcffef530814421239a708776f8400d /block
parenta9b305ba291fb74f7ff732b3d7b8f4c812431ddf (diff)
qcow2: Fix preallocation bdrv_pwrite to wrong file
With an external data file, preallocate_co() must write the final byte to the external data file, not to the qcow2 image file. This is harmless for preallocation of newly created images (only the qcow2 file size is increased to the virtual disk size while it should be much smaller), but with preallocated resize, it could in theory cause visible corruption if the metadata of the image is larger than the data (e.g. lots of bitmaps). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/qcow2.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index d507ee0686..3ace3b2209 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2723,6 +2723,7 @@ static int qcow2_set_up_encryption(BlockDriverState *bs,
static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
uint64_t new_length)
{
+ BDRVQcow2State *s = bs->opaque;
uint64_t bytes;
uint64_t host_offset = 0;
unsigned int cur_bytes;
@@ -2771,7 +2772,7 @@ static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
*/
if (host_offset != 0) {
uint8_t data = 0;
- ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1,
+ ret = bdrv_pwrite(s->data_file, (host_offset + cur_bytes) - 1,
&data, 1);
if (ret < 0) {
return ret;