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 0405533F8AD; Wed, 29 Oct 2025 18:11:33 +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=1761761494; cv=none; b=nagMEzhEljlFe8+CY0zr6jxSIOAQz7uDYFddR2ip1J/CWJr3UZ488hMcERPXi+BN1LF0P2icKeyItKR/5I5xpysbfJUPruOYBhZ2zrzs3wMXQ6kotNCpdBq9XA1pMIweGozl0yTOT1zGsbWnJ237u30oxpMvHFz2zEi7hDL1AI0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761761494; c=relaxed/simple; bh=bO6AaglsKevRn2PyLL2DL1nGgqSin/EhNrA1KFV6V6g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E8cvle2FVTkuIATBRHvhTzDG2lRSQHM/VJrVBl0Z4+svzVOYDUUKqHAbIq/XYs/eSX2pHtdcLY8sIVqNyB92oQ4TYEn+yJsXSJa6pMh15xIKuBkrb7pPfYJ39YWz15mi7vqHyiHT9p+DDi3ExMtUp7e+Fs9IAIe/FGjAmrftASU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Xj0IR5Jc; 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="Xj0IR5Jc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F852C4CEF7; Wed, 29 Oct 2025 18:11:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761761493; bh=bO6AaglsKevRn2PyLL2DL1nGgqSin/EhNrA1KFV6V6g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Xj0IR5Jc0Qyx1fLF065f4wlVHQwbo4YwZ8jobjcf9yEDc+ZRJe6iPsC/SMN06zoym ajlXUVs6CIOc0gD8mAmNtrn99tkmvH7+t8JwUeOu3AemXH6dVZW+58zUBp3KTGwWd5 3gg/KoKX7XOHg+ZYz6LNNlhknyhk3JNzqHLN8YnKqf0iLbmgge/2Gxen2p/u0NznYP wHuLvAo+iDtmLgWSS/23UQcNl+S6Qjj/YwOUbws42OiSy3zPN0Y09V8nYMrTE4RArk 2qbgEZZ4oLrXXKdNjsU7DuWuF8X0C4FwKQQtxxoItQSWL9O0kt+c5fqRuw4YJNW/aT IdOnBY9QkcsEg== Date: Wed, 29 Oct 2025 11:11:32 -0700 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] xfs: fix write failures in software-provided atomic writes Message-ID: <20251029181132.GH3356773@frogsfrogsfrogs> References: 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 In-Reply-To: From: Darrick J. Wong With the 5 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" --- 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..e1da06b157cf94 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; 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; + 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: + 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;