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 lists1p.gnu.org (lists1p.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 1A0FECA6007 for ; Wed, 7 Oct 2026 16:36:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xEUcl-0004jO-Ih; Wed, 07 Oct 2026 12:36:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xEUbW-00030O-8F for qemu-devel@nongnu.org; Wed, 07 Oct 2026 12:34:55 -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 1xEUbP-0006NV-RF for qemu-devel@nongnu.org; Wed, 07 Oct 2026 12:34:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1791390887; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YpXHoTdAVpgqoHk/C8gDqtbYtH9QeYbVOrvBeGRIkJM=; b=YVmNw1EvqNMDStPTUeaZ7rnPNPJejG+Us5/9MSoHSzzb8HXJEQlLctVROg5igaL2AwJVHZ c6oCCmvUWUQpaFanCispOxa0r+pmitPrC7pCckpFitUG6z25Qwd283DM4iikGZE1QLNbJC XYSWaBO0+m3Uc2E8oUF4tt7lUHt3QG0= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-634-sFQbAEXMNeOG_ECpoLMhUg-1; Wed, 07 Oct 2026 12:34:45 -0400 X-MC-Unique: sFQbAEXMNeOG_ECpoLMhUg-1 X-Mimecast-MFC-AGG-ID: sFQbAEXMNeOG_ECpoLMhUg_1791390884 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0E9F31955D80; Wed, 7 Oct 2026 16:34:44 +0000 (UTC) Received: from merkur.redhat.com (unknown [10.44.32.219]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B33F51956087; Wed, 7 Oct 2026 16:34:42 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, richard.henderson@linaro.org, qemu-devel@nongnu.org Subject: [PULL 17/21] file-posix: add statx(STATX_DIOALIGN) support Date: Wed, 7 Oct 2026 18:32:58 +0200 Message-ID: <20261007163302.332250-18-kwolf@redhat.com> In-Reply-To: <20261007163302.332250-1-kwolf@redhat.com> References: <20261007163302.332250-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 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: 10 X-Spam_score: 1.0 X-Spam_bar: + X-Spam_report: (1.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.24, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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 From: Stefan Hajnoczi Linux v6.1 commit 825cf206ed51 ("statx: add direct I/O alignment information") added an interface to fetch O_DIRECT alignment values for block devices and file systems. Prefer STATX_DIOALIGN to older interfaces and probing, but keep them as fallbacks in case STATX_DIOALIGN cannot provide the information. STATX_DIOALIGN support as of Linux 6.1: - btrfs: no - ext4: yes - XFS: yes - block devices: yes - dm-crypt: yes This change fixes #1290 ("IO alignment probing delivers incorrect results on Linux when used with e.g. dm-crypt") on Linux host kernel version 6.1 or later by avoiding the problematic probing code in raw_probe_alignment(). It would be nice to fix the probing code but I have not been able to reproduce it. Stable/LTS distros ship Linux 6.1+, so the number of users without STATX_DIOALIGN is becoming small. Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/1290 Cc: Eric Biggers Signed-off-by: Stefan Hajnoczi Message-ID: <20260922154351.226540-1-stefanha@redhat.com> Reviewed-by: Ben Chaney Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/file-posix.c | 56 +++++++++++++++++++++++++++++++--------------- 1 file changed, 38 insertions(+), 18 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index 39d6a34456c..328adb57233 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -426,28 +426,48 @@ static void raw_probe_alignment(BlockDriverState *bs, int fd, Error **errp) bs->bl.request_alignment = 0; s->buf_align = 0; - /* Let's try to use the logical blocksize for the alignment. */ - if (probe_logical_blocksize(fd, &bs->bl.request_alignment) < 0) { - bs->bl.request_alignment = 0; - } -#ifdef __linux__ +#if defined(__linux__) && defined(STATX_DIOALIGN) + struct statx stx; + /* - * The XFS ioctl definitions are shipped in extra packages that might - * not always be available. Since we just need the XFS_IOC_DIOINFO ioctl - * here, we simply use our own definition instead: + * Linux 6.1 introduced an interface for both block devices and file + * systems. The system call returns with the STATX_DIOALIGN bit cleared + * when the information is unavailable. */ - struct xfs_dioattr { - uint32_t d_mem; - uint32_t d_miniosz; - uint32_t d_maxiosz; - } da; - if (ioctl(fd, _IOR('X', 30, struct xfs_dioattr), &da) >= 0) { - bs->bl.request_alignment = da.d_miniosz; - /* The kernel returns wrong information for d_mem */ - /* s->buf_align = da.d_mem; */ + if (statx(fd, "", AT_EMPTY_PATH, STATX_DIOALIGN, &stx) == 0 && + (stx.stx_mask & STATX_DIOALIGN)) { + bs->bl.request_alignment = stx.stx_dio_offset_align; + s->buf_align = stx.stx_dio_mem_align; + } +#endif /* defined(__linux__) && defined(STATX_DIOALIGN) */ + +#ifdef __linux__ + if (!bs->bl.request_alignment) { + /* + * The XFS ioctl definitions are shipped in extra packages that might + * not always be available. Since we just need the XFS_IOC_DIOINFO ioctl + * here, we simply use our own definition instead: + */ + struct xfs_dioattr { + uint32_t d_mem; + uint32_t d_miniosz; + uint32_t d_maxiosz; + } da; + if (ioctl(fd, _IOR('X', 30, struct xfs_dioattr), &da) >= 0) { + bs->bl.request_alignment = da.d_miniosz; + /* The kernel returns wrong information for d_mem */ + /* s->buf_align = da.d_mem; */ + } + } +#endif /* __linux__ */ + + /* Let's try to use the logical blocksize for the alignment. */ + if (!bs->bl.request_alignment) { + if (probe_logical_blocksize(fd, &bs->bl.request_alignment) < 0) { + bs->bl.request_alignment = 0; + } } -#endif /* * If we could not get the sizes so far, we can only guess them. First try -- 2.56.0