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| author | Kevin Wolf <kwolf@redhat.com> | 2012-03-16 15:02:38 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2012-04-20 15:57:29 +0200 |
| commit | 6377af48b0445e7ee50db6e0bd73a3a70098f5f4 (patch) | |
| tree | e3b5171b5645490af6a392662790d7de88247a69 /block/qcow2-cluster.c | |
| parent | 6744cbab8cd63b7ce72b3eee4f0055007acf0798 (diff) | |
| download | qemu-6377af48b0445e7ee50db6e0bd73a3a70098f5f4.tar.gz qemu-6377af48b0445e7ee50db6e0bd73a3a70098f5f4.tar.bz2 qemu-6377af48b0445e7ee50db6e0bd73a3a70098f5f4.zip | |
qcow2: Support reading zero clusters
This adds support for reading zero clusters in version 3 images.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2-cluster.c')
| -rw-r--r-- | block/qcow2-cluster.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index b8836ba009..5e5f5cf9ad 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -453,6 +453,12 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, c = 1; *cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK; break; + case QCOW2_CLUSTER_ZERO: + c = count_contiguous_clusters(nb_clusters, s->cluster_size, + &l2_table[l2_index], 0, + QCOW_OFLAG_COMPRESSED | QCOW_OFLAG_ZERO); + *cluster_offset = 0; + break; case QCOW2_CLUSTER_UNALLOCATED: /* how many empty clusters ? */ c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]); @@ -461,7 +467,8 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, case QCOW2_CLUSTER_NORMAL: /* how many allocated clusters ? */ c = count_contiguous_clusters(nb_clusters, s->cluster_size, - &l2_table[l2_index], 0, QCOW_OFLAG_COMPRESSED); + &l2_table[l2_index], 0, + QCOW_OFLAG_COMPRESSED | QCOW_OFLAG_ZERO); *cluster_offset &= L2E_OFFSET_MASK; break; } @@ -720,6 +727,7 @@ static int count_cow_clusters(BDRVQcowState *s, int nb_clusters, break; case QCOW2_CLUSTER_UNALLOCATED: case QCOW2_CLUSTER_COMPRESSED: + case QCOW2_CLUSTER_ZERO: break; default: abort(); @@ -868,9 +876,10 @@ again: && (cluster_offset & QCOW_OFLAG_COPIED)) { /* We keep all QCOW_OFLAG_COPIED clusters */ - keep_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size, - &l2_table[l2_index], 0, - QCOW_OFLAG_COPIED); + keep_clusters = + count_contiguous_clusters(nb_clusters, s->cluster_size, + &l2_table[l2_index], 0, + QCOW_OFLAG_COPIED | QCOW_OFLAG_ZERO); assert(keep_clusters <= nb_clusters); nb_clusters -= keep_clusters; } else { |