From b85ee45334585c49c5489a303336df119408763a Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Mon, 25 Sep 2017 09:55:22 -0500 Subject: qcow2: Switch qcow2_measure() to byte-based iteration This is new code, but it is easier to read if it makes passes over the image using bytes rather than sectors (and will get easier in the future when bdrv_get_block_status is converted to byte-based). Signed-off-by: Eric Blake Reviewed-by: John Snow Reviewed-by: Kevin Wolf Reviewed-by: Fam Zheng Signed-off-by: Kevin Wolf --- block/qcow2.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) (limited to 'block') diff --git a/block/qcow2.c b/block/qcow2.c index 970006f..b8da8ca 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -3673,20 +3673,19 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, */ required = virtual_size; } else { - int cluster_sectors = cluster_size / BDRV_SECTOR_SIZE; - int64_t sector_num; + int64_t offset; int pnum = 0; - for (sector_num = 0; - sector_num < ssize / BDRV_SECTOR_SIZE; - sector_num += pnum) { - int nb_sectors = MIN(ssize / BDRV_SECTOR_SIZE - sector_num, - BDRV_REQUEST_MAX_SECTORS); + for (offset = 0; offset < ssize; + offset += pnum * BDRV_SECTOR_SIZE) { + int nb_sectors = MIN(ssize - offset, + BDRV_REQUEST_MAX_BYTES) / BDRV_SECTOR_SIZE; BlockDriverState *file; int64_t ret; ret = bdrv_get_block_status_above(in_bs, NULL, - sector_num, nb_sectors, + offset >> BDRV_SECTOR_BITS, + nb_sectors, &pnum, &file); if (ret < 0) { error_setg_errno(&local_err, -ret, @@ -3699,12 +3698,11 @@ static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs, } else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) == (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) { /* Extend pnum to end of cluster for next iteration */ - pnum = ROUND_UP(sector_num + pnum, cluster_sectors) - - sector_num; + pnum = (ROUND_UP(offset + pnum * BDRV_SECTOR_SIZE, + cluster_size) - offset) >> BDRV_SECTOR_BITS; /* Count clusters we've seen */ - required += (sector_num % cluster_sectors + pnum) * - BDRV_SECTOR_SIZE; + required += offset % cluster_size + pnum * BDRV_SECTOR_SIZE; } } } -- cgit v1.1