From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C417C433EF for ; Thu, 4 Nov 2021 11:33:08 +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 2610061168 for ; Thu, 4 Nov 2021 11:33:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2610061168 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:58770 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1miazS-0001Sl-TB for qemu-devel@archiver.kernel.org; Thu, 04 Nov 2021 07:33:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47994) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1miaxt-00006L-OF for qemu-devel@nongnu.org; Thu, 04 Nov 2021 07:31:29 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:56034) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1miaxp-0001kN-PZ for qemu-devel@nongnu.org; Thu, 04 Nov 2021 07:31:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636025485; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=iMULFL0+u86e4XjrBLjJ8jfevodljvo7Fnipj9bAY08=; b=ZWCPtkefQ0/dBFATEmwXf4Q6Idnd7nHq0MDaqaq9oTCMEKptDD6oY3Hiy13U8Ace5ik69K +BfuqlHmq/UtMgCGUeANttRStqNnPnDx85qxQA2HFXCfDRhLgJ8uJbq4nu9ZUWGXiRbgKe xWSULQG/uPxxve260SfBWXvOsEUXYvw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-324-ixA5EMugO5CNJ9oSR3QAzg-1; Thu, 04 Nov 2021 07:31:22 -0400 X-MC-Unique: ixA5EMugO5CNJ9oSR3QAzg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4317210A8E02; Thu, 4 Nov 2021 11:31:21 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.193.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3AE0E197FC; Thu, 4 Nov 2021 11:31:19 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH] file-posix: Fix alignment after reopen changing O_DIRECT Date: Thu, 4 Nov 2021 12:31:09 +0100 Message-Id: <20211104113109.56336-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.648, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, hreitz@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" At the end of a reopen, we already call bdrv_refresh_limits(), which should update bs->request_alignment according to the new file descriptor. However, raw_probe_alignment() relies on s->needs_alignment and just uses 1 if it isn't set. We neglected to update this field, so starting with cache=writeback and then reopening with cache=none means that we get an incorrect bs->request_alignment == 1 and unaligned requests fail instead of being automatically aligned. Fix this by recalculating s->needs_alignment in raw_refresh_limits() before calling raw_probe_alignment(). Signed-off-by: Kevin Wolf --- block/file-posix.c | 20 ++++++++++++++++---- tests/qemu-iotests/142 | 22 ++++++++++++++++++++++ tests/qemu-iotests/142.out | 15 +++++++++++++++ 3 files changed, 53 insertions(+), 4 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 7a27c83060..3f14e47096 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -167,6 +167,7 @@ typedef struct BDRVRawState { int page_cache_inconsistent; /* errno from fdatasync failure */ bool has_fallocate; bool needs_alignment; + bool force_alignment; bool drop_cache; bool check_cache_dropped; struct { @@ -351,6 +352,17 @@ static bool dio_byte_aligned(int fd) return false; } +static int raw_needs_alignment(BlockDriverState *bs) +{ + BDRVRawState *s = bs->opaque; + + if ((bs->open_flags & BDRV_O_NOCACHE) != 0 && !dio_byte_aligned(s->fd)) { + return true; + } + + return s->force_alignment; +} + /* Check if read is allowed with given memory buffer and length. * * This function is used to check O_DIRECT memory buffer and request alignment. @@ -728,9 +740,6 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, s->has_discard = true; s->has_write_zeroes = true; - if ((bs->open_flags & BDRV_O_NOCACHE) != 0 && !dio_byte_aligned(s->fd)) { - s->needs_alignment = true; - } if (fstat(s->fd, &st) < 0) { ret = -errno; @@ -784,9 +793,10 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, * so QEMU makes sure all IO operations on the device are aligned * to sector size, or else FreeBSD will reject them with EINVAL. */ - s->needs_alignment = true; + s->force_alignment = true; } #endif + s->needs_alignment = raw_needs_alignment(bs); #ifdef CONFIG_XFS if (platform_test_xfs_fd(s->fd)) { @@ -1251,7 +1261,9 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) BDRVRawState *s = bs->opaque; struct stat st; + s->needs_alignment = raw_needs_alignment(bs); raw_probe_alignment(bs, s->fd, errp); + bs->bl.min_mem_alignment = s->buf_align; bs->bl.opt_mem_alignment = MAX(s->buf_align, qemu_real_host_page_size); diff --git a/tests/qemu-iotests/142 b/tests/qemu-iotests/142 index 69fd10ef51..07003c597a 100755 --- a/tests/qemu-iotests/142 +++ b/tests/qemu-iotests/142 @@ -350,6 +350,28 @@ info block backing-file" echo "$hmp_cmds" | run_qemu -drive "$files","$ids" | grep "Cache" +echo +echo "--- Alignment after changing O_DIRECT ---" +echo + +# Directly test the protocol level: Can unaligned requests succeed even if +# O_DIRECT was only enabled through a reopen and vice versa? + +$QEMU_IO --cache=writeback -f file $TEST_IMG <