From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36770) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwS9f-0006xb-2T for qemu-devel@nongnu.org; Fri, 07 Apr 2017 07:34:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cwS9e-0002tO-90 for qemu-devel@nongnu.org; Fri, 07 Apr 2017 07:34:15 -0400 From: Vladimir Sementsov-Ogievskiy Date: Fri, 7 Apr 2017 14:34:04 +0300 Message-Id: <20170407113404.9351-1-vsementsov@virtuozzo.com> Subject: [Qemu-devel] [PATCH] qemu-img: improve convert_iteration_sectors() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: mreitz@redhat.com, kwolf@redhat.com, den@openvz.org Do not do extra call to _get_block_status() Signed-off-by: Vladimir Sementsov-Ogievskiy --- Also, I'm not sure about last line: s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_DATA; (which is equal to old code) may be, it should be s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_ZERO; as it is the case, when range is not allocated at all. Should we copy it in this case? qemu-img.c | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index b220cf71d7..490f6e97f6 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1554,9 +1554,15 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) if (s->sector_next_status <= sector_num) { BlockDriverState *file; - ret = bdrv_get_block_status(blk_bs(s->src[src_cur]), - sector_num - src_cur_offset, - n, &n, &file); + if (s->target_has_backing) { + ret = bdrv_get_block_status(blk_bs(s->src[src_cur]), + sector_num - src_cur_offset, + n, &n, &file); + } else { + ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL, + sector_num - src_cur_offset, + n, &n, &file); + } if (ret < 0) { return ret; } @@ -1565,26 +1571,8 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) s->status = BLK_ZERO; } else if (ret & BDRV_BLOCK_DATA) { s->status = BLK_DATA; - } else if (!s->target_has_backing) { - /* Without a target backing file we must copy over the contents of - * the backing file as well. */ - /* Check block status of the backing file chain to avoid - * needlessly reading zeroes and limiting the iteration to the - * buffer size */ - ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL, - sector_num - src_cur_offset, - n, &n, &file); - if (ret < 0) { - return ret; - } - - if (ret & BDRV_BLOCK_ZERO) { - s->status = BLK_ZERO; - } else { - s->status = BLK_DATA; - } } else { - s->status = BLK_BACKING_FILE; + s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_DATA; } s->sector_next_status = sector_num + n; -- 2.11.1