From patchwork Thu Oct 22 18:13:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Shinkevich X-Patchwork-Id: 11851775 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A948014B2 for ; Thu, 22 Oct 2020 18:17:44 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 49E0E208C3 for ; Thu, 22 Oct 2020 18:17:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 49E0E208C3 Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=nongnu.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:51606 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kVf9j-0002wU-5z for patchwork-qemu-devel@patchwork.kernel.org; Thu, 22 Oct 2020 14:17:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48528) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kVf60-0000Vo-HL; Thu, 22 Oct 2020 14:13:52 -0400 Received: from relay.sw.ru ([185.231.240.75]:52102 helo=relay3.sw.ru) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kVf5x-0001ns-JX; Thu, 22 Oct 2020 14:13:52 -0400 Received: from [172.16.25.136] (helo=localhost.sw.ru) by relay3.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1kVf5r-005dVw-M5; Thu, 22 Oct 2020 21:13:43 +0300 To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, fam@euphon.net, stefanha@redhat.com, kwolf@redhat.com, mreitz@redhat.com, armbru@redhat.com, jsnow@redhat.com, eblake@redhat.com, den@openvz.org, vsementsov@virtuozzo.com, andrey.shinkevich@virtuozzo.com Subject: [PATCH v12 07/14] copy-on-read: limit COR operations to bottom node Date: Thu, 22 Oct 2020 21:13:36 +0300 Message-Id: <1603390423-980205-8-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1603390423-980205-1-git-send-email-andrey.shinkevich@virtuozzo.com> References: <1603390423-980205-1-git-send-email-andrey.shinkevich@virtuozzo.com> Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.shinkevich@virtuozzo.com; helo=relay3.sw.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/22 14:13:46 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" Reply-to: Andrey Shinkevich X-Patchwork-Original-From: Andrey Shinkevich via From: Andrey Shinkevich Limit COR operations to the bottom node (inclusively) in the backing chain when the bottom node name is given. It will be useful for a block stream job when the COR-filter is applied. The bottom node is passed as the base itself may change due to concurrent commit jobs on the same backing chain. Signed-off-by: Andrey Shinkevich Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/copy-on-read.c | 42 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 2 deletions(-) diff --git a/block/copy-on-read.c b/block/copy-on-read.c index 3d8e4db..8178a91 100644 --- a/block/copy-on-read.c +++ b/block/copy-on-read.c @@ -123,8 +123,46 @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs, size_t qiov_offset, int flags) { - return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, - flags | BDRV_REQ_COPY_ON_READ); + int64_t n = 0; + int local_flags; + int ret; + BDRVStateCOR *state = bs->opaque; + + if (!state->bottom_bs) { + return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset, + flags | BDRV_REQ_COPY_ON_READ); + } + + while (bytes) { + local_flags = flags; + + /* In case of failure, try to copy-on-read anyway */ + ret = bdrv_is_allocated(bs->file->bs, offset, bytes, &n); + if (!ret || ret < 0) { + ret = bdrv_is_allocated_above(bdrv_backing_chain_next(bs->file->bs), + state->bottom_bs, true, offset, + n, &n); + if (ret == 1 || ret < 0) { + local_flags |= BDRV_REQ_COPY_ON_READ; + } + /* Finish earlier if the end of a backing file has been reached */ + if (ret == 0 && n == 0) { + break; + } + } + + ret = bdrv_co_preadv_part(bs->file, offset, n, qiov, qiov_offset, + local_flags); + if (ret < 0) { + return ret; + } + + offset += n; + qiov_offset += n; + bytes -= n; + } + + return 0; }