diff options
| -rw-r--r-- | block/qcow2.c | 5 | ||||
| -rw-r--r-- | block/qcow2.h | 5 |
2 files changed, 10 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c index 6738daa247..fb4584d3ee 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1444,6 +1444,11 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options, } } + s->subclusters_per_cluster = + has_subclusters(s) ? QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER : 1; + s->subcluster_size = s->cluster_size / s->subclusters_per_cluster; + s->subcluster_bits = ctz32(s->subcluster_size); + /* Check support for various header values */ if (header.refcount_order > 6) { error_setg(errp, "Reference count entry width too large; may not " diff --git a/block/qcow2.h b/block/qcow2.h index 2064dd3d85..eee4c8de9c 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -78,6 +78,8 @@ /* The cluster reads as all zeros */ #define QCOW_OFLAG_ZERO (1ULL << 0) +#define QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER 32 + #define MIN_CLUSTER_BITS 9 #define MAX_CLUSTER_BITS 21 @@ -295,6 +297,9 @@ typedef struct BDRVQcow2State { int cluster_bits; int cluster_size; int l2_slice_size; + int subcluster_bits; + int subcluster_size; + int subclusters_per_cluster; int l2_bits; int l2_size; int l1_size; |