On 24.08.21 10:38, Vladimir Sementsov-Ogievskiy wrote:
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 <vsement...@virtuozzo.com>
Reviewed-by: Max Reitz <mre...@redhat.com>
---
block/copy-before-write.h | 1 -
include/block/block-copy.h | 5 +--
block/backup.c | 62 ++++++--------------------------------
block/block-copy.c | 51 ++++++++++++++++++++++++++++++-
block/copy-before-write.c | 10 +++---
5 files changed, 66 insertions(+), 63 deletions(-)
[...]
diff --git a/block/block-copy.c b/block/block-copy.c
index e83870ff81..b0e0a38330 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
[...]
@@ -342,14 +343,57 @@ void block_copy_set_copy_opts(BlockCopyState *s, bool
use_copy_range,
}
}
+static int64_t block_copy_calculate_cluster_size(BlockDriverState *target,
+ Error **errp)
+{
+ int ret;
+ BlockDriverInfo bdi;
+ bool target_does_cow = bdrv_backing_chain_next(target);
+
+ /*
+ * If there is no backing file on the target, we cannot rely on COW if our
+ * backup cluster size is smaller than the target cluster size. Even for
+ * targets with a backing file, try to avoid COW if possible.
+ */
+ ret = bdrv_get_info(target, &bdi);
+ if (ret == -ENOTSUP && !target_does_cow) {
+ /* Cluster size is not defined */
+ warn_report("The target block device doesn't provide "
+ "information about the block size and it doesn't have a "
+ "backing file. The default block size of %u bytes is "
+ "used. If the actual block size of the target exceeds "
+ "this default, the backup may be unusable",
+ BLOCK_COPY_CLUSTER_SIZE_DEFAULT);
I get some build errors in the gitlab CI because of this – I think we
need to add a qemu/error-report.h include in block/block-copy.c now. (I
don’t know why this works for some configurations, apparently, but not
for others...)
Is it OK if I add it to this patch?
diff --git a/block/block-copy.c b/block/block-copy.c
index b0e0a38330..5d0076ac93 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -21,6 +21,7 @@
#include "qemu/units.h"
#include "qemu/coroutine.h"
#include "block/aio_task.h"
+#include "qemu/error-report.h"
#define BLOCK_COPY_MAX_COPY_RANGE (16 * MiB)
#define BLOCK_COPY_MAX_BUFFER (1 * MiB)
Hanna
