From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60848) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cZIKL-0008Vh-Et for qemu-devel@nongnu.org; Thu, 02 Feb 2017 09:25:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cZIKI-0001Qu-A5 for qemu-devel@nongnu.org; Thu, 02 Feb 2017 09:25:33 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:28714 helo=relay.sw.ru) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cZIKH-0001Pr-UO for qemu-devel@nongnu.org; Thu, 02 Feb 2017 09:25:30 -0500 From: "Denis V. Lunev" Date: Thu, 2 Feb 2017 17:25:15 +0300 Message-Id: <1486045515-8009-1-git-send-email-den@openvz.org> Subject: [Qemu-devel] [PATCH v2 1/1] mirror: do not increase offset during initial zero_or_discard phase List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Anton Nefedov , "Denis V . Lunev" , Jeff Cody , Kevin Wolf , Max Reitz , Eric Blake From: Anton Nefedov If explicit zeroing out before mirroring is required for the target image, it moves the block job offset counter to EOF, then offset and len counters count the image size twice. There is no harm but stats are confusing, specifically the progress of the operation is always reported as 99% by management tools. The patch skips offset increase for the first "technical" pass over the image. This should not cause any further harm. Signed-off-by: Anton Nefedov Signed-off-by: Denis V. Lunev CC: Jeff Cody CC: Kevin Wolf CC: Max Reitz CC: Eric Blake --- Changes from v1: - changed the approach - we do not allow to increase the offset rather then to move it back - description rewritten - kludges to tests are removed as not actually needed with this approach block/mirror.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 301ba92..f100f5d 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -69,6 +69,7 @@ typedef struct MirrorBlockJob { bool waiting_for_io; int target_cluster_sectors; int max_iov; + bool initial_zeroing_ongoing; } MirrorBlockJob; typedef struct MirrorOp { @@ -117,9 +118,10 @@ static void mirror_iteration_done(MirrorOp *op, int ret) if (s->cow_bitmap) { bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); } - s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; + if (!s->initial_zeroing_ongoing) { + s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; + } } - qemu_iovec_destroy(&op->qiov); g_free(op); @@ -566,6 +568,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) return 0; } + s->initial_zeroing_ongoing = true; for (sector_num = 0; sector_num < end; ) { int nb_sectors = MIN(end - sector_num, QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS); @@ -573,6 +576,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) mirror_throttle(s); if (block_job_is_cancelled(&s->common)) { + s->initial_zeroing_ongoing = false; return 0; } @@ -587,6 +591,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) } mirror_wait_for_all_io(s); + s->initial_zeroing_ongoing = false; } /* First part, loop on the sectors and initialize the dirty bitmap. */ -- 2.7.4