block/backup: move cluster size calculation to block-copy

The main consumer of cluster-size is block-copy. Let's calculate it
here instead of passing through backup-top.

We are going to publish copy-before-write filter soon, so it will be
created through options. But we don't want for now to make explicit
option for cluster-size, let's continue to calculate it automatically.
So, now is the time to get rid of cluster_size argument for
bdrv_cbw_append().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210824083856.17408-10-vsementsov@virtuozzo.com>
[hreitz: Add qemu/error-report.h include to block/block-copy.c]
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index 235251a640..a7996d54db 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -37,7 +37,6 @@
 typedef struct BDRVCopyBeforeWriteState {
     BlockCopyState *bcs;
     BdrvChild *target;
-    int64_t cluster_size;
 } BDRVCopyBeforeWriteState;
 
 static coroutine_fn int cbw_co_preadv(
@@ -52,13 +51,14 @@ static coroutine_fn int cbw_do_copy_before_write(BlockDriverState *bs,
 {
     BDRVCopyBeforeWriteState *s = bs->opaque;
     uint64_t off, end;
+    int64_t cluster_size = block_copy_cluster_size(s->bcs);
 
     if (flags & BDRV_REQ_WRITE_UNCHANGED) {
         return 0;
     }
 
-    off = QEMU_ALIGN_DOWN(offset, s->cluster_size);
-    end = QEMU_ALIGN_UP(offset + bytes, s->cluster_size);
+    off = QEMU_ALIGN_DOWN(offset, cluster_size);
+    end = QEMU_ALIGN_UP(offset + bytes, cluster_size);
 
     return block_copy(s->bcs, off, end - off, true);
 }
@@ -169,7 +169,6 @@ BlockDriver bdrv_cbw_filter = {
 BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
                                   BlockDriverState *target,
                                   const char *filter_node_name,
-                                  uint64_t cluster_size,
                                   bool compress,
                                   BlockCopyState **bcs,
                                   Error **errp)
@@ -214,9 +213,8 @@ BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
     }
     appended = true;
 
-    state->cluster_size = cluster_size;
     state->bcs = block_copy_state_new(top->backing, state->target,
-                                      cluster_size, false, compress, errp);
+                                      false, compress, errp);
     if (!state->bcs) {
         error_prepend(errp, "Cannot create block-copy-state: ");
         goto fail;