From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32873) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bhI2j-0002fy-Da for qemu-devel@nongnu.org; Tue, 06 Sep 2016 11:12:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bhI2d-0008Aq-QV for qemu-devel@nongnu.org; Tue, 06 Sep 2016 11:12:09 -0400 From: "Denis V. Lunev" Date: Tue, 6 Sep 2016 18:11:19 +0300 Message-Id: <1473174679-18413-1-git-send-email-den@openvz.org> Subject: [Qemu-devel] [PATCH 1/1] mirror: fix improperly filled copy_bitmap for mirror block job List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org, qemu-devel@nongnu.org Cc: den@openvz.org, Jeff Cody , Kevin Wolf , Max Reitz bdrv_is_allocated_above() returns true in the case if qcow2 even for completely zeroed areas as BDRV_BLOCK_ALLOCATED flag is set in both cases. Though we have completely zeroed out the image just above or it was already zeroed. The patch stops using bdrv_is_allocated_above() wrapper and switches to bdrv_get_block_status_above() to distinguish zeroed areas and areas with data to avoid extra IO operations, which could be VERY slow. Signed-off-by: Denis V. Lunev CC: Jeff Cody CC: Kevin Wolf CC: Max Reitz --- block/mirror.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index e0b3f41..87edbd8 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -552,7 +552,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) BlockDriverState *base = s->base; BlockDriverState *bs = blk_bs(s->common.blk); BlockDriverState *target_bs = blk_bs(s->target); - int ret, n; + int n; end = s->bdev_length / BDRV_SECTOR_SIZE; @@ -590,6 +590,8 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) /* Just to make sure we are not exceeding int limit. */ int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, end - sector_num); + int64_t status; + BlockDriverState *file; mirror_throttle(s); @@ -597,13 +599,14 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) return 0; } - ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); - if (ret < 0) { - return ret; + status = bdrv_get_block_status_above(bs, base, sector_num, + nb_sectors, &n, &file); + if (status < 0) { + return status; } assert(n > 0); - if (ret == 1) { + if (status & BDRV_BLOCK_DATA) { bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); } sector_num += n; -- 2.7.4