From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:45025) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UDHjN-0001bl-4o for qemu-devel@nongnu.org; Wed, 06 Mar 2013 12:02:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UDHjI-00025K-HQ for qemu-devel@nongnu.org; Wed, 06 Mar 2013 12:02:16 -0500 Sender: Paolo Bonzini From: Paolo Bonzini Date: Wed, 6 Mar 2013 18:02:01 +0100 Message-Id: <1362589321-21402-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH] qcow2: make is_allocated return true for zero clusters List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, qemu-stable@nongnu.org, stefanha@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-stable@nongnu.org Signed-off-by: Paolo Bonzini --- block/qcow2.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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); Stage this hunk [y,n,q,a,d,/,e,?]? y 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; -- 1.8.1.2