From: Paolo Bonzini <pbonz...@redhat.com>
Otherwise, live migration of the top layer will miss zero clusters and
let the backing file show through. This also matches what is done in qed.
QCOW2_CLUSTER_ZERO clusters are invalid in v2 image files. Check this
directly in qcow2_get_cluster_offset instead of replicating the test
everywhere.
Cc: qemu-sta...@nongnu.org
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
(cherry picked from commit 381b487d54ba18c73df9db8452028a330058c505)
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
block/qcow2-cluster.c | 3 +++
block/qcow2.c | 6 +-----
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 56fccf9..bb04432 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -454,6 +454,9 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t
offset,
*cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK;
break;
case QCOW2_CLUSTER_ZERO:
+ if (s->qcow_version < 3) {
+ return -EIO;
+ }
c = count_contiguous_clusters(nb_clusters, s->cluster_size,
&l2_table[l2_index], 0,
QCOW_OFLAG_COMPRESSED | QCOW_OFLAG_ZERO);
diff --git a/block/qcow2.c b/block/qcow2.c
index 7610e56..b4c7c54 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -584,7 +584,7 @@ static int coroutine_fn
qcow2_co_is_allocated(BlockDriverState *bs,
*pnum = 0;
}
- return (cluster_offset != 0);
+ return (cluster_offset != 0) || (ret == QCOW2_CLUSTER_ZERO);
}
/* handle reading after the end of the backing file */
@@ -665,10 +665,6 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState
*bs, int64_t sector_num,
break;
case QCOW2_CLUSTER_ZERO:
- if (s->qcow_version < 3) {
- ret = -EIO;
- goto fail;
- }
qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
break;
--
1.7.9.5
