We are going to implement push backup with fleecing scheme. This means
that backup job will be a fleecing user and therefore will not need
separate copy-before-write filter. Instead it will consider source as
constant unchanged drive. Of course backup will want to unshare writes
on source for this case. But we want to do copy-before-write
operations. Still these operations may be considered as
write-unchanged. Add corresponding option to block-copy now, to use in
the following commit.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
include/block/block-copy.h | 3 ++-
block/block-copy.c | 9 ++++++---
block/copy-before-write.c | 2 +-
3 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/include/block/block-copy.h b/include/block/block-copy.h
index a11e1620f6..a66f81d314 100644
--- a/include/block/block-copy.h
+++ b/include/block/block-copy.h
@@ -25,7 +25,8 @@ typedef struct BlockCopyState BlockCopyState;
typedef struct BlockCopyCallState BlockCopyCallState;
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
- BdrvDirtyBitmap *bitmap, Error **errp);
+ BdrvDirtyBitmap *bitmap,
+ bool write_unchanged, Error **errp);
/* Function should be called prior any actual copy request */
void block_copy_set_copy_opts(BlockCopyState *s, bool use_copy_range,
diff --git a/block/block-copy.c b/block/block-copy.c
index f70f1ad993..e2cf67e335 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -280,7 +280,8 @@ void block_copy_set_copy_opts(BlockCopyState *s, bool
use_copy_range,
bool compress)
{
/* Keep BDRV_REQ_SERIALISING set (or not set) in block_copy_state_new() */
- s->write_flags = (s->write_flags & BDRV_REQ_SERIALISING) |
+ s->write_flags = (s->write_flags &
+ (BDRV_REQ_SERIALISING | BDRV_REQ_WRITE_UNCHANGED)) |
(compress ? BDRV_REQ_WRITE_COMPRESSED : 0);
if (s->max_transfer < s->cluster_size) {
@@ -341,7 +342,8 @@ static int64_t
block_copy_calculate_cluster_size(BlockDriverState *target,
}
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
- BdrvDirtyBitmap *bitmap, Error **errp)
+ BdrvDirtyBitmap *bitmap,
+ bool write_unchanged, Error **errp)
{
ERRP_GUARD();
BlockCopyState *s;
@@ -394,7 +396,8 @@ BlockCopyState *block_copy_state_new(BdrvChild *source,
BdrvChild *target,
.copy_bitmap = copy_bitmap,
.cluster_size = cluster_size,
.len = bdrv_dirty_bitmap_size(copy_bitmap),
- .write_flags = (is_fleecing ? BDRV_REQ_SERIALISING : 0),
+ .write_flags = (is_fleecing ? BDRV_REQ_SERIALISING : 0) |
+ (write_unchanged ? BDRV_REQ_WRITE_UNCHANGED : 0),
.mem = shres_create(BLOCK_COPY_MAX_MEM),
.max_transfer = QEMU_ALIGN_DOWN(
block_copy_max_transfer(source, target),
diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index 2e39159a7e..f95c54dbdf 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -213,7 +213,7 @@ static int cbw_open(BlockDriverState *bs, QDict *options,
int flags,
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
bs->file->bs->supported_zero_flags);
- s->bcs = block_copy_state_new(bs->file, s->target, bitmap, errp);
+ s->bcs = block_copy_state_new(bs->file, s->target, bitmap, false, errp);
if (!s->bcs) {
error_prepend(errp, "Cannot create block-copy-state: ");
return -EINVAL;
--
2.31.1
