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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 659C3CAC5B8 for ; Thu, 2 Oct 2025 19:40:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v4P7x-0007NN-Dd; Thu, 02 Oct 2025 15:38:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v4P7q-0007Lc-Q4 for qemu-devel@nongnu.org; Thu, 02 Oct 2025 15:38:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v4P7X-0000Yn-24 for qemu-devel@nongnu.org; Thu, 02 Oct 2025 15:38:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1759433856; 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=2N7TxRwqPqrfZN4JT6cRtHTIeTswLRGkUOZOj8Gn1n4=; b=HnkRJiVyC4LbD7mES4L8k+33DlCIuFrOvw2hI8wtriGtJT/PTYm6TeCzNfoOSLkGu0WsNX XgakOPfdHv4ugiaXcD1QvbNgCa5ukyZX6SARlt77VBKioKuBGTVuzkyeUVkUWQzUFtPHJz 7rZj6XYf/cH6TWzqEfe1/BMhTU8eK0I= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-632-n7EmqgGYNSCkvn1z5wd7Rw-1; Thu, 02 Oct 2025 15:37:33 -0400 X-MC-Unique: n7EmqgGYNSCkvn1z5wd7Rw-1 X-Mimecast-MFC-AGG-ID: n7EmqgGYNSCkvn1z5wd7Rw_1759433852 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9BCE71800366; Thu, 2 Oct 2025 19:37:32 +0000 (UTC) Received: from localhost (unknown [10.2.16.139]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id F292E18004D8; Thu, 2 Oct 2025 19:37:31 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, Jean-Louis Dupond , Hanna Reitz , Stefan Hajnoczi Subject: [PATCH 0/3] block: use pwrite_zeroes_alignment when writing first sector Date: Thu, 2 Oct 2025 14:39:57 -0400 Message-ID: <20251002184000.410486-1-stefanha@redhat.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.451, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org This series fixes a bug I introduced in commit 5634622bcb33 ("file-posix: allow BLKZEROOUT with -t writeback"). The Linux fallocate(2) and ioctl(BLKZEROOUT) syscalls require logical block size alignment of the offset and length, even when the file is opened in buffered I/O mode where read/write operations do not require alignment. The fix is to populate the pwrite_zeroes_alignment block limits field and to use that limit in create_file_fallback_zero_first_sector(). One issue I want to raise is that pwrite_zeroes_alignment is an "optimal alignment" hint. Hence create_file_fallback_zero_first_sector() had to be modified to honor the limit explicitly. The block layer doesn't automatically apply padding in order to align requests. This is different from how QEMU's block layer pwrite/pread works, where it does automatically apply padding and read/modify/write as necessary. If you want consistency, please let me know. Stefan Hajnoczi (3): file-posix: populate pwrite_zeroes_alignment block: use pwrite_zeroes_alignment when writing first sector iotests: add Linux loop device image creation test include/system/block-backend-io.h | 1 + block.c | 3 +- block/block-backend.c | 11 ++++ block/file-posix.c | 17 ++++++ tests/qemu-iotests/tests/loop-create-file | 59 +++++++++++++++++++ tests/qemu-iotests/tests/loop-create-file.out | 8 +++ 6 files changed, 98 insertions(+), 1 deletion(-) create mode 100755 tests/qemu-iotests/tests/loop-create-file create mode 100644 tests/qemu-iotests/tests/loop-create-file.out -- 2.51.0