On Mon, Aug 13, 2018 at 04:19:52AM +0200, Max Reitz wrote: > Signed-off-by: Max Reitz <mre...@redhat.com>
Reviewed-by: Jeff Cody <jc...@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 >