From: Paolo Bonzini Date: Wed, 6 Mar 2013 17:02:01 +0000 (+0100) Subject: qcow2: make is_allocated return true for zero clusters X-Git-Tag: v1.4.1~40 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d3652a1b286063f02425adc18515804272ebef18;p=thirdparty%2Fqemu.git qcow2: make is_allocated return true for zero clusters 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-stable@nongnu.org Signed-off-by: Paolo Bonzini Signed-off-by: Stefan Hajnoczi (cherry picked from commit 381b487d54ba18c73df9db8452028a330058c505) Signed-off-by: Michael Roth --- diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 56fccf9487e..bb044327d63 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 7610e569e39..b4c7c543243 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;