diff options
| -rw-r--r-- | block/block-copy.c | 41 |
1 files changed, 31 insertions, 10 deletions
diff --git a/block/block-copy.c b/block/block-copy.c index e2d7b3b887..ddd61c1652 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -70,16 +70,19 @@ void block_copy_state_free(BlockCopyState *s) g_free(s); } +static uint32_t block_copy_max_transfer(BdrvChild *source, BdrvChild *target) +{ + return MIN_NON_ZERO(INT_MAX, + MIN_NON_ZERO(source->bs->bl.max_transfer, + target->bs->bl.max_transfer)); +} + BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, int64_t cluster_size, BdrvRequestFlags write_flags, Error **errp) { BlockCopyState *s; BdrvDirtyBitmap *copy_bitmap; - uint32_t max_transfer = - MIN_NON_ZERO(INT_MAX, - MIN_NON_ZERO(source->bs->bl.max_transfer, - target->bs->bl.max_transfer)); copy_bitmap = bdrv_create_dirty_bitmap(source->bs, cluster_size, NULL, errp); @@ -99,7 +102,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, .mem = shres_create(BLOCK_COPY_MAX_MEM), }; - if (max_transfer < cluster_size) { + if (block_copy_max_transfer(source, target) < cluster_size) { /* * copy_range does not respect max_transfer. We don't want to bother * with requests smaller than block-copy cluster size, so fallback to @@ -114,12 +117,11 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, s->copy_size = cluster_size; } else { /* - * copy_range does not respect max_transfer (it's a TODO), so we factor - * that in here. + * We enable copy-range, but keep small copy_size, until first + * successful copy_range (look at block_copy_do_copy). */ s->use_copy_range = true; - s->copy_size = MIN(MAX(cluster_size, BLOCK_COPY_MAX_COPY_RANGE), - QEMU_ALIGN_DOWN(max_transfer, cluster_size)); + s->copy_size = MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER); } QLIST_INIT(&s->inflight_reqs); @@ -172,6 +174,22 @@ static int coroutine_fn block_copy_do_copy(BlockCopyState *s, s->copy_size = MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER); /* Fallback to read+write with allocated buffer */ } else { + if (s->use_copy_range) { + /* + * Successful copy-range. Now increase copy_size. copy_range + * does not respect max_transfer (it's a TODO), so we factor + * that in here. + * + * Note: we double-check s->use_copy_range for the case when + * parallel block-copy request unsets it during previous + * bdrv_co_copy_range call. + */ + s->copy_size = + MIN(MAX(s->cluster_size, BLOCK_COPY_MAX_COPY_RANGE), + QEMU_ALIGN_DOWN(block_copy_max_transfer(s->source, + s->target), + s->cluster_size)); + } goto out; } } @@ -179,7 +197,10 @@ static int coroutine_fn block_copy_do_copy(BlockCopyState *s, /* * In case of failed copy_range request above, we may proceed with buffered * request larger than BLOCK_COPY_MAX_BUFFER. Still, further requests will - * be properly limited, so don't care too much. + * be properly limited, so don't care too much. Moreover the most likely + * case (copy_range is unsupported for the configuration, so the very first + * copy_range request fails) is handled by setting large copy_size only + * after first successful copy_range. */ bounce_buffer = qemu_blockalign(s->source->bs, nbytes); |