diff options
Diffstat (limited to 'block/mirror.c')
| -rw-r--r-- | block/mirror.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/block/mirror.c b/block/mirror.c index 930ac96a86..42ebc3b9e9 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -218,7 +218,9 @@ static inline void mirror_wait_for_io(MirrorBlockJob *s) } /* Submit async read while handling COW. - * Returns: nb_sectors if no alignment is necessary, or + * Returns: The number of sectors copied after and including sector_num, + * excluding any sectors copied prior to sector_num due to alignment. + * This will be nb_sectors if no alignment is necessary, or * (new_end - sector_num) if tail is rounded up or down due to * alignment or buffer limit. */ @@ -227,7 +229,7 @@ static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num, { BlockBackend *source = s->common.blk; int sectors_per_chunk, nb_chunks; - int ret = nb_sectors; + int ret; MirrorOp *op; sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; @@ -235,6 +237,7 @@ static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num, /* We can only handle as much as buf_size at a time. */ nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors); assert(nb_sectors); + ret = nb_sectors; if (s->cow_bitmap) { ret += mirror_cow_align(s, §or_num, &nb_sectors); |