From: Max Reitz <[email protected]> In write-blocking mode, all writes to the top node directly go to the target. We must only mirror chunks of data that are aligned to the job's granularity, because that is how the dirty bitmap works. Therefore, the request alignment for writes must be the job's granularity (in write-blocking mode).
Unfortunately, this forces all reads and writes to have the same granularity (we only need this alignment for writes to the target, not the source), but that is something to be fixed another time. Cc: [email protected] Signed-off-by: Max Reitz <[email protected]> Message-id: [email protected] Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]> Fixes: d06107ade0ce74dc39739bac80de84b51ec18546 Signed-off-by: Max Reitz <[email protected]> (cherry picked from commit 9adc1cb49af8d4e54f57980b1eed5c0a4b2dafa6) Signed-off-by: Michael Roth <[email protected]> --- block/mirror.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/block/mirror.c b/block/mirror.c index ff15cfb197..062dc42867 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1477,6 +1477,15 @@ static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c, *nshared = BLK_PERM_ALL; } +static void bdrv_mirror_top_refresh_limits(BlockDriverState *bs, Error **errp) +{ + MirrorBDSOpaque *s = bs->opaque; + + if (s && s->job && s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING) { + bs->bl.request_alignment = s->job->granularity; + } +} + /* Dummy node that provides consistent read to its users without requiring it * from its backing file and that allows writes on the backing file chain. */ static BlockDriver bdrv_mirror_top = { @@ -1489,6 +1498,7 @@ static BlockDriver bdrv_mirror_top = { .bdrv_co_block_status = bdrv_co_block_status_from_backing, .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename, .bdrv_child_perm = bdrv_mirror_top_child_perm, + .bdrv_refresh_limits = bdrv_mirror_top_refresh_limits, }; static void mirror_start_job(const char *job_id, BlockDriverState *bs, @@ -1627,6 +1637,25 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs, s->should_complete = true; } + /* + * Must be called before we start tracking writes, but after + * + * ((MirrorBlockJob *) + * ((MirrorBDSOpaque *) + * mirror_top_bs->opaque + * )->job + * )->copy_mode + * + * has the correct value. + * (We start tracking writes as of the following + * bdrv_create_dirty_bitmap() call.) + */ + bdrv_refresh_limits(mirror_top_bs, &local_err); + if (local_err) { + error_propagate(errp, local_err); + goto fail; + } + s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); if (!s->dirty_bitmap) { goto fail; -- 2.17.1
