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-rw-r--r--block/qed.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/block/qed.c b/block/qed.c
index a02dbfd72d..21cb239870 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1363,10 +1363,21 @@ static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs,
int nb_sectors)
{
BlockDriverAIOCB *blockacb;
+ BDRVQEDState *s = bs->opaque;
QEDWriteZeroesCB cb = { .done = false };
QEMUIOVector qiov;
struct iovec iov;
+ /* Refuse if there are untouched backing file sectors */
+ if (bs->backing_hd) {
+ if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) {
+ return -ENOTSUP;
+ }
+ if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) {
+ return -ENOTSUP;
+ }
+ }
+
/* Zero writes start without an I/O buffer. If a buffer becomes necessary
* then it will be allocated during request processing.
*/