From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39967) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b1YGD-0003Aw-OJ for qemu-devel@nongnu.org; Sat, 14 May 2016 08:01:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b1YG7-0006mm-OK for qemu-devel@nongnu.org; Sat, 14 May 2016 08:01:32 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:21027 helo=relay.sw.ru) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b1YG7-0006ls-Bb for qemu-devel@nongnu.org; Sat, 14 May 2016 08:01:27 -0400 From: "Denis V. Lunev" Date: Sat, 14 May 2016 15:01:10 +0300 Message-Id: <1463227273-27523-4-git-send-email-den@openvz.org> In-Reply-To: <1463227273-27523-1-git-send-email-den@openvz.org> References: <1463227273-27523-1-git-send-email-den@openvz.org> Subject: [Qemu-devel] [PATCH 3/6] qcow2: simplify logic in qcow2_co_write_zeroes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: den@openvz.org, Kevin Wolf Unaligned request could occupy only one cluster. This is true since the previous commit. Simplify the code taking this considiration into account. There are no other changes so far. Signed-off-by: Denis V. Lunev CC: Kevin Wolf --- block/qcow2.c | 23 +++++------------------ 1 file changed, 5 insertions(+), 18 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 62febfc..9a54bbd 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -2436,33 +2436,20 @@ static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, int tail = (sector_num + nb_sectors) % s->cluster_sectors; if (head != 0 || tail != 0) { - int64_t cl_end = -1; + int64_t cl_start = sector_num - head; - sector_num -= head; - nb_sectors += head; + assert(cl_start + s->cluster_sectors >= sector_num + nb_sectors); - if (tail != 0) { - nb_sectors += s->cluster_sectors - tail; - } + sector_num = cl_start; + nb_sectors = s->cluster_sectors; if (!is_zero_cluster(bs, sector_num)) { return -ENOTSUP; } - if (nb_sectors > s->cluster_sectors) { - /* Technically the request can cover 2 clusters, f.e. 4k write - at s->cluster_sectors - 2k offset. One of these cluster can - be zeroed, one unallocated */ - cl_end = sector_num + nb_sectors - s->cluster_sectors; - if (!is_zero_cluster(bs, cl_end)) { - return -ENOTSUP; - } - } - qemu_co_mutex_lock(&s->lock); /* We can have new write after previous check */ - if (!is_zero_cluster_top_locked(bs, sector_num) || - (cl_end > 0 && !is_zero_cluster_top_locked(bs, cl_end))) { + if (!is_zero_cluster_top_locked(bs, sector_num)) { qemu_co_mutex_unlock(&s->lock); return -ENOTSUP; } -- 2.5.0