diff mbox series

[v4,10/30] qcow2: Add offset_to_sc_index()

Message ID daf4559e162269c1be195d954d4cf38e9b2231f1.1584468723.git.berto@igalia.com (mailing list archive)
State New, archived
Headers show
Series Add subcluster allocation to qcow2 | expand

Commit Message

Alberto Garcia March 17, 2020, 6:16 p.m. UTC 
For a given offset, return the subcluster number within its cluster
(i.e. with 32 subclusters per cluster it returns a number between 0
and 31).

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2.h | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Vladimir Sementsov-Ogievskiy April 13, 2020, 11:02 a.m. UTC | #1 
17.03.2020 21:16, Alberto Garcia wrote:
> For a given offset, return the subcluster number within its cluster
> (i.e. with 32 subclusters per cluster it returns a number between 0
> and 31).
> 
> Signed-off-by: Alberto Garcia<berto@igalia.com>
> Reviewed-by: Max Reitz<mreitz@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
diff mbox series

Patch

diff --git a/block/qcow2.h b/block/qcow2.h
index 3052b14dc0..06929072d2 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -566,6 +566,11 @@  static inline int offset_to_l2_slice_index(BDRVQcow2State *s, int64_t offset)
     return (offset >> s->cluster_bits) & (s->l2_slice_size - 1);
 }
 
+static inline int offset_to_sc_index(BDRVQcow2State *s, int64_t offset)
+{
+    return (offset >> s->subcluster_bits) & (s->subclusters_per_cluster - 1);
+}
+
 static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s)
 {
     return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);