From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 681AF2222CB; Wed, 5 Nov 2025 00:12:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762301521; cv=none; b=U+A0C5gOAUxCMv/3ON1gtsgV+lVjX0ACn086Lxc//POs5zfEpOE8X5uMMKl3OETXohV6U2210Zb3llMa0D8yTCwPjANEbcRzFVRMQ4mHDswpjwO5WBtdZpsxDVkUkscEy0rVRL7llYaPqzHxBfKpKe6RHNXBTEffhwcwdZd3QhI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762301521; c=relaxed/simple; bh=ogp/Edro7JS3yLYMD6nY9wbm+7/v/eEGchm3BKxcCFc=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=dv3YlR2t/yKfirdkI/zrBb/gZp2XGUd4lfhXU1YzCbQL2MXJTWq6P8acuzayD6VRruSpeevHkYjq60KrgSasxhBXqSYyQQeCKA8TX6UJWE1jOB+OeFDOjSFj2qndfSs2f1dCPbbP/h16OqORHN955Ds0PfCiAq7dgj7NdkUfw4U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=o6nazgHd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="o6nazgHd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09F84C116B1; Wed, 5 Nov 2025 00:12:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762301521; bh=ogp/Edro7JS3yLYMD6nY9wbm+7/v/eEGchm3BKxcCFc=; h=Date:From:To:Cc:Subject:From; b=o6nazgHdvqlBjoPpBaiQ2BpfYx0qdo+KEfzjeWd6kER3UkU1LQEBOHr2wLwSz2iLj QMgmq03XebCqYO/dEUmlzEOQ+myEQSxfFNC5D38pLP9s4FG1QC//D0GM4du2RL9LG4 0nhRosKrRJwfrGg2uffvefJrOU/V4sEJyh5gxazxL3wEPYgjF+ehcMghTBHcLmV8lZ xKuj8/2DG5msXEs8PyiHYUkXOJfkzUUWZ+JBdYvIPB8QU5W6wR4M9Zt7mHGD+ww/wS amlYUKCJsakzYzTRo7zsRBnCuE/JMg/dxPMSjbGBS1PqsF4DP14UXKNYyMmJgKiuM7 rNgfFZvklrUww== Date: Tue, 4 Nov 2025 16:12:00 -0800 From: "Darrick J. Wong" To: Carlos Maiolino Cc: Ojaswin Mujoo , Zorro Lang , fstests@vger.kernel.org, Ritesh Harjani , john.g.garry@oracle.com, linux-xfs@vger.kernel.org Subject: [PATCH v2 1/2] xfs: fix delalloc write failures in software-provided atomic writes Message-ID: <20251105001200.GV196370@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline From: Darrick J. Wong With the 20 Oct 2025 release of fstests, generic/521 fails for me on regular (aka non-block-atomic-writes) storage: QA output created by 521 dowrite: write: Input/output error LOG DUMP (8553 total operations): 1( 1 mod 256): SKIPPED (no operation) 2( 2 mod 256): WRITE 0x7e000 thru 0x8dfff (0x10000 bytes) HOLE 3( 3 mod 256): READ 0x69000 thru 0x79fff (0x11000 bytes) 4( 4 mod 256): FALLOC 0x53c38 thru 0x5e853 (0xac1b bytes) INTERIOR 5( 5 mod 256): COPY 0x55000 thru 0x59fff (0x5000 bytes) to 0x25000 thru 0x29fff 6( 6 mod 256): WRITE 0x74000 thru 0x88fff (0x15000 bytes) 7( 7 mod 256): ZERO 0xedb1 thru 0x11693 (0x28e3 bytes) with a warning in dmesg from iomap about XFS trying to give it a delalloc mapping for a directio write. Fix the software atomic write iomap_begin code to convert the reservation into a written mapping. This doesn't fix the data corruption problems reported by generic/760, but it's a start. Cc: # v6.16 Fixes: bd1d2c21d5d249 ("xfs: add xfs_atomic_write_cow_iomap_begin()") Signed-off-by: "Darrick J. Wong" Reviewed-by: John Garry --- v2: adjust label names for consistency, add rvb --- fs/xfs/xfs_iomap.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index d3f6e3e42a1191..788bfdce608a7d 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -1130,7 +1130,7 @@ xfs_atomic_write_cow_iomap_begin( return -EAGAIN; trace_xfs_iomap_atomic_write_cow(ip, offset, length); - +retry: xfs_ilock(ip, XFS_ILOCK_EXCL); if (!ip->i_cowfp) { @@ -1141,6 +1141,8 @@ xfs_atomic_write_cow_iomap_begin( if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap)) cmap.br_startoff = end_fsb; if (cmap.br_startoff <= offset_fsb) { + if (isnullstartblock(cmap.br_startblock)) + goto convert_delay; xfs_trim_extent(&cmap, offset_fsb, count_fsb); goto found; } @@ -1169,8 +1171,10 @@ xfs_atomic_write_cow_iomap_begin( if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap)) cmap.br_startoff = end_fsb; if (cmap.br_startoff <= offset_fsb) { - xfs_trim_extent(&cmap, offset_fsb, count_fsb); xfs_trans_cancel(tp); + if (isnullstartblock(cmap.br_startblock)) + goto convert_delay; + xfs_trim_extent(&cmap, offset_fsb, count_fsb); goto found; } @@ -1210,6 +1214,19 @@ xfs_atomic_write_cow_iomap_begin( xfs_iunlock(ip, XFS_ILOCK_EXCL); return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq); +convert_delay: + xfs_iunlock(ip, XFS_ILOCK_EXCL); + error = xfs_bmapi_convert_delalloc(ip, XFS_COW_FORK, offset, iomap, + NULL); + if (error) + return error; + + /* + * Try the lookup again, because the delalloc conversion might have + * turned the COW mapping into unwritten, but we need it to be in + * written state. + */ + goto retry; out_unlock: xfs_iunlock(ip, XFS_ILOCK_EXCL); return error;