From d3652a1b286063f02425adc18515804272ebef18 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 6 Mar 2013 18:02:01 +0100 Subject: 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 --- 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 56fccf9487..bb044327d6 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 7610e569e3..b4c7c54324 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; -- cgit v1.2.1