Signed-off-by: Max Reitz <mre...@redhat.com> --- block/mirror.c | 54 +++++++++++++++++++++++++++++++++----------------- 1 file changed, 36 insertions(+), 18 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c index c28b6159d5..34cb8293b2 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -305,42 +305,60 @@ static inline void coroutine_fn mirror_co_wait_for_any_operation(s, false); } -/* Perform a mirror copy operation. +/* + * Restrict *bytes to how much we can actually handle, and align the + * [*offset, *bytes] range to clusters if COW is needed. * - * *op->bytes_handled is set to the number of bytes copied after and + * *bytes_handled is set to the number of bytes copied after and * including offset, excluding any bytes copied prior to offset due - * to alignment. This will be op->bytes if no alignment is necessary, - * or (new_end - op->offset) if the tail is rounded up or down due to + * to alignment. This will be *bytes if no alignment is necessary, or + * (new_end - *offset) if the tail is rounded up or down due to * alignment or buffer limit. */ -static void coroutine_fn mirror_co_read(void *opaque) +static void mirror_align_for_copy(MirrorBlockJob *s, + int64_t *offset, uint64_t *bytes, + int64_t *bytes_handled) { - MirrorOp *op = opaque; - MirrorBlockJob *s = op->s; - int nb_chunks; - uint64_t ret; uint64_t max_bytes; max_bytes = s->granularity * s->max_iov; /* We can only handle as much as buf_size at a time. */ - op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes)); - assert(op->bytes); - assert(op->bytes < BDRV_REQUEST_MAX_BYTES); - *op->bytes_handled = op->bytes; + *bytes = MIN(s->buf_size, MIN(max_bytes, *bytes)); + assert(*bytes); + assert(*bytes < BDRV_REQUEST_MAX_BYTES); + *bytes_handled = *bytes; if (s->cow_bitmap) { - *op->bytes_handled += mirror_cow_align(s, &op->offset, &op->bytes); + *bytes_handled += mirror_cow_align(s, offset, bytes); } /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */ - assert(*op->bytes_handled <= UINT_MAX); - assert(op->bytes <= s->buf_size); + assert(*bytes_handled <= UINT_MAX); + assert(*bytes <= s->buf_size); /* The offset is granularity-aligned because: * 1) Caller passes in aligned values; * 2) mirror_cow_align is used only when target cluster is larger. */ - assert(QEMU_IS_ALIGNED(op->offset, s->granularity)); + assert(QEMU_IS_ALIGNED(*offset, s->granularity)); /* The range is sector-aligned, since bdrv_getlength() rounds up. */ - assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE)); + assert(QEMU_IS_ALIGNED(*bytes, BDRV_SECTOR_SIZE)); +} + +/* Perform a mirror copy operation. + * + * *op->bytes_handled is set to the number of bytes copied after and + * including offset, excluding any bytes copied prior to offset due + * to alignment. This will be op->bytes if no alignment is necessary, + * or (new_end - op->offset) if the tail is rounded up or down due to + * alignment or buffer limit. + */ +static void coroutine_fn mirror_co_read(void *opaque) +{ + MirrorOp *op = opaque; + MirrorBlockJob *s = op->s; + int nb_chunks; + uint64_t ret; + + mirror_align_for_copy(s, &op->offset, &op->bytes, op->bytes_handled); nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); while (s->buf_free_count < nb_chunks) { -- 2.17.1