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 CB46F2E8B85; Wed, 29 Oct 2025 18:13:36 +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=1761761616; cv=none; b=D2Isi/719GFQSHoWLD4d+l80LNkraJ4oT23/wSlUSmODYts+lEVkqQEvW+c3TzmL8lMtc4+ymhFS4HAKlOxqnQDOJ/IvtznhOl4Zw4vy1WkrNEAhIlMAUhcWvlGJvt6iS3RbWd0TK7rT1D7tY+rutulYgg/Z8SMIrFtKZBar/94= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761761616; c=relaxed/simple; bh=O4pe0KaVYZJ0MRJ62aWnJfMj3faZYC7std7ttBoAfbk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DF8Mc+JZBa9iG9G24yLddGQP5GwDD1gzH6XE1qKBpX7y/T4N8aaeewQYyEAwaqQOG7r46UhBbqSPNei5EYm/FnLjwRmgBia3eRkIlR7+wxsKNFmVQsme7T11jXvLeUs8WSgBGY47aAHQoEFNZWjzxPaoMD4Z+uHKW/ULlBI9gwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Qz88XQJ9; 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="Qz88XQJ9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C516C4CEF7; Wed, 29 Oct 2025 18:13:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761761616; bh=O4pe0KaVYZJ0MRJ62aWnJfMj3faZYC7std7ttBoAfbk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Qz88XQJ9zKHAbGZg5PxJkjG0or11MnFuSlnvz/8tjBZ9pyG5eU721l0WAvtmHwlFm mqKyrkYqEl2KNEfM5O/lA1Q1T2ajYV0qLIBSPEfzZSP+h5OtlCh4wAnnTbFOVzJp3E RbKCTtYOXzhCc56qg0vc/x3xTHLizK+EN4bEv9utTA7i4ZttuBGI/1uEHrbp1Um+ml wQ+Rva7RVEnZWpAsWDTqLdA1HwS3KkqqLBZbeX4/tOlUCboUUad9yXnBR0s2kOzg9s erbQ1dMayhPRFdqg74N3UVOkWqIxgPLXbXFPNq6H4qHuIGPBNICQd4jw4iC5TVe9f8 gfjBKkO2AwjEw== Date: Wed, 29 Oct 2025 11:13:36 -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: Re: [PATCH] xfs: fix write failures in software-provided atomic writes Message-ID: <20251029181336.GJ3356773@frogsfrogsfrogs> References: <20251029181132.GH3356773@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: fstests@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: <20251029181132.GH3356773@frogsfrogsfrogs> On Wed, Oct 29, 2025 at 11:11:32AM -0700, Darrick J. Wong wrote: > 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. Grrrr I forgot to remove the reply-to tag when I harvested the cc list from this old thread for a bug fix. Sorry about that. --D > > 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; >