| Message ID | eea31d0b30552e61f5921c6e693034cc75c724c6.1584468723.git.berto@igalia.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add subcluster allocation to qcow2 | expand |
On 17.03.20 19:16, Alberto Garcia wrote: > This patch adds the following new fields to BDRVQcow2State: > > - subclusters_per_cluster: Number of subclusters in a cluster > - subcluster_size: The size of each subcluster, in bytes > - subcluster_bits: No. of bits so 1 << subcluster_bits = subcluster_size > > Images without subclusters are treated as if they had exactly one, > with subcluster_size = cluster_size. > > Signed-off-by: Alberto Garcia <berto@igalia.com> > --- > block/qcow2.h | 5 +++++ > block/qcow2.c | 5 +++++ > 2 files changed, 10 insertions(+) Reviewed-by: Max Reitz <mreitz@redhat.com>
17.03.2020 21:16, Alberto Garcia wrote: > This patch adds the following new fields to BDRVQcow2State: > > - subclusters_per_cluster: Number of subclusters in a cluster > - subcluster_size: The size of each subcluster, in bytes > - subcluster_bits: No. of bits so 1 << subcluster_bits = subcluster_size > > Images without subclusters are treated as if they had exactly one, exactly one subcluster per cluster... > with subcluster_size = cluster_size. > > Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
diff --git a/block/qcow2.h b/block/qcow2.h index 55298750bd..3052b14dc0 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 @@ -284,6 +286,9 @@ 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; diff --git a/block/qcow2.c b/block/qcow2.c index 5b6ceaa2fa..239e0ad3d9 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1380,6 +1380,11 @@ 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 "
This patch adds the following new fields to BDRVQcow2State: - subclusters_per_cluster: Number of subclusters in a cluster - subcluster_size: The size of each subcluster, in bytes - subcluster_bits: No. of bits so 1 << subcluster_bits = subcluster_size Images without subclusters are treated as if they had exactly one, with subcluster_size = cluster_size. Signed-off-by: Alberto Garcia <berto@igalia.com> --- block/qcow2.h | 5 +++++ block/qcow2.c | 5 +++++ 2 files changed, 10 insertions(+)