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authorAndrey Drobyshev <andrey.drobyshev@virtuozzo.com>2023-07-11 20:25:51 +0300
committerStefan Hajnoczi <stefanha@redhat.com>2023-08-30 07:39:10 -0400
commitc54483b6f45a0c84e230728a1a9e7adf90345e15 (patch)
tree5bf9bacf290a472997dc5cb756125cf5eb92ba9f /include
parentf187609f27b261702a17f79d20bf252ee0d4f9cd (diff)
downloadfocaccia-qemu-c54483b6f45a0c84e230728a1a9e7adf90345e15.tar.gz
focaccia-qemu-c54483b6f45a0c84e230728a1a9e7adf90345e15.zip
block: add subcluster_size field to BlockDriverInfo
This is going to be used in the subsequent commit as requests alignment
(in particular, during copy-on-read).  This value only makes sense for
the formats which support subclusters (currently QCOW2 only).  If this
field isn't set by driver's own bdrv_get_info() implementation, we
simply set it equal to the cluster size thus treating each cluster as
having a single subcluster.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230711172553.234055-2-andrey.drobyshev@virtuozzo.com>
Diffstat (limited to 'include')
-rw-r--r--include/block/block-common.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/block/block-common.h b/include/block/block-common.h
index e15395f2cb..df5ffc8d09 100644
--- a/include/block/block-common.h
+++ b/include/block/block-common.h
@@ -132,6 +132,11 @@ typedef struct BlockZoneWps {
 typedef struct BlockDriverInfo {
     /* in bytes, 0 if irrelevant */
     int cluster_size;
+    /*
+     * A fraction of cluster_size, if supported (currently QCOW2 only); if
+     * disabled or unsupported, set equal to cluster_size.
+     */
+    int subcluster_size;
     /* offset at which the VM state can be saved (0 if not possible) */
     int64_t vm_state_offset;
     bool is_dirty;