From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55682) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e0Uxn-0000OF-52 for qemu-devel@nongnu.org; Fri, 06 Oct 2017 11:55:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e0Uxm-0002y1-1M for qemu-devel@nongnu.org; Fri, 06 Oct 2017 11:54:59 -0400 From: Kevin Wolf Date: Fri, 6 Oct 2017 17:53:45 +0200 Message-Id: <20171006155422.10135-18-kwolf@redhat.com> In-Reply-To: <20171006155422.10135-1-kwolf@redhat.com> References: <20171006155422.10135-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 17/54] qcow2: Switch qcow2_measure() to byte-based iteration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Eric Blake 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(-) diff --git a/block/qcow2.c b/block/qcow2.c index 970006fc1d..b8da8ca105 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; } } } -- 2.13.6