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 1F251219301; Mon, 24 Feb 2025 20:20:35 +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=1740428436; cv=none; b=aS/1ZWdJwRD2kB9ptF1D2/ULakRqAHtm2xxnqDXThTIeKcPNmGasRRhfJsY34MxCvxxoK64VDXhITjsSsWnvz2KTplDU0VjpmqxNC+J8owBhuyrOStp0AbuZTdE8yVHWqx2zcTGY1P0lAmvJnXs61n6fJex/UXIJ494nJXOv2QE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740428436; c=relaxed/simple; bh=6VAqcp8i/KksTRnjFl8hZ1PVyC+q8YxP3Kyhwai1Ibs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=M7U/vMurP2Rm0huVhA2/JzU9I1KGlnw42ag6jBv7rqmG64+HKfEzfQri3a//WuwMPDGSw8riPpZDbMXBs7OyHQXJ2nq5ea+xQ2UfVFclMKmBxlgN+Vu3MX/LyMRSJELxJY891PfJqPWLLVQ8DBHvHoCCYvVqAkEHYCjrAABINRk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IQBYy678; 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="IQBYy678" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 808A5C4CEDD; Mon, 24 Feb 2025 20:20:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740428435; bh=6VAqcp8i/KksTRnjFl8hZ1PVyC+q8YxP3Kyhwai1Ibs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IQBYy678jd44jdnG4APN0sq4DrqtNqvjjyui5kWyGLPH18QZpNUyvuN3yCUwfPPKj Oe+E+cwzCIiaL2mw+VOOyeoOLuRKWd95cD+JUQuyJSOgZLFZvlNga+A8BgGpmLwU4p cE+3K8RUrf/XYQcrMFXohjfgPivA25T2k7zwZJdS3/Jd8iRoqrFvzJxR0gRLf57JHB buv7TRQeLux1FLmzfl8YvXUamn5toFAHbaiXhjLQQ+cS/+eHo7KXWFY6oiuS4mJbxk DAfOHb+Jz/+GW8nuM3RBh1YQziFuAYZ4mNHLe8vpCZZhxnkymGr6f8JorFmEeRfP+h 1IjUFP57O0xnA== Date: Mon, 24 Feb 2025 12:20:34 -0800 From: "Darrick J. Wong" To: John Garry Cc: brauner@kernel.org, cem@kernel.org, dchinner@redhat.com, hch@lst.de, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ojaswin@linux.ibm.com, ritesh.list@gmail.com, martin.petersen@oracle.com, tytso@mit.edu, linux-ext4@vger.kernel.org Subject: Re: [PATCH v2 09/11] xfs: Commit CoW-based atomic writes atomically Message-ID: <20250224202034.GE21808@frogsfrogsfrogs> References: <20250213135619.1148432-1-john.g.garry@oracle.com> <20250213135619.1148432-10-john.g.garry@oracle.com> Precedence: bulk X-Mailing-List: linux-ext4@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: <20250213135619.1148432-10-john.g.garry@oracle.com> On Thu, Feb 13, 2025 at 01:56:17PM +0000, John Garry wrote: > When completing a CoW-based write, each extent range mapping update is > covered by a separate transaction. > > For a CoW-based atomic write, all mappings must be changed at once, so > change to use a single transaction. > > Signed-off-by: John Garry > --- > fs/xfs/xfs_file.c | 5 ++++- > fs/xfs/xfs_reflink.c | 45 ++++++++++++++++++++++++++++++++++++++++++++ > fs/xfs/xfs_reflink.h | 3 +++ > 3 files changed, 52 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 9762fa503a41..243640fe4874 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -527,7 +527,10 @@ xfs_dio_write_end_io( > nofs_flag = memalloc_nofs_save(); > > if (flags & IOMAP_DIO_COW) { > - error = xfs_reflink_end_cow(ip, offset, size); > + if (iocb->ki_flags & IOCB_ATOMIC) > + error = xfs_reflink_end_atomic_cow(ip, offset, size); > + else > + error = xfs_reflink_end_cow(ip, offset, size); > if (error) > goto out; > } > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c > index 3dab3ba900a3..d097d33dc000 100644 > --- a/fs/xfs/xfs_reflink.c > +++ b/fs/xfs/xfs_reflink.c > @@ -986,6 +986,51 @@ xfs_reflink_end_cow( > trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_); > return error; > } > +int > +xfs_reflink_end_atomic_cow( > + struct xfs_inode *ip, > + xfs_off_t offset, > + xfs_off_t count) > +{ > + xfs_fileoff_t offset_fsb; > + xfs_fileoff_t end_fsb; > + int error = 0; > + struct xfs_mount *mp = ip->i_mount; > + struct xfs_trans *tp; > + unsigned int resblks; > + > + trace_xfs_reflink_end_cow(ip, offset, count); > + > + offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); > + end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count); Use @mp here instead of walking the pointer. > + > + resblks = (end_fsb - offset_fsb) * > + XFS_NEXTENTADD_SPACE_RES(mp, 1, XFS_DATA_FORK); How did you arrive at this computation? The "b" parameter to XFS_NEXTENTADD_SPACE_RES is usually the worst case number of mappings that you're going to change on this file. I think that quantity is (end_fsb - offset_fsb)? > + > + error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, > + XFS_TRANS_RESERVE, &tp); > + if (error) > + return error; > + > + xfs_ilock(ip, XFS_ILOCK_EXCL); > + xfs_trans_ijoin(tp, ip, 0); > + > + while (end_fsb > offset_fsb && !error) > + error = xfs_reflink_end_cow_extent_locked(tp, ip, &offset_fsb, > + end_fsb); Overly long line, and the continuation line only needs to be indented two more tabs. > + > + if (error) { > + trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_); > + goto out_cancel; > + } > + error = xfs_trans_commit(tp); > + xfs_iunlock(ip, XFS_ILOCK_EXCL); > + return 0; Why is it ok to drop @error here? Shouldn't a transaction commit error should be reported to the writer thread? --D > +out_cancel: > + xfs_trans_cancel(tp); > + xfs_iunlock(ip, XFS_ILOCK_EXCL); > + return error; > +} > > /* > * Free all CoW staging blocks that are still referenced by the ondisk refcount > diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h > index 754d2bb692d3..ca945d98e823 100644 > --- a/fs/xfs/xfs_reflink.h > +++ b/fs/xfs/xfs_reflink.h > @@ -43,6 +43,9 @@ extern int xfs_reflink_cancel_cow_range(struct xfs_inode *ip, xfs_off_t offset, > xfs_off_t count, bool cancel_real); > extern int xfs_reflink_end_cow(struct xfs_inode *ip, xfs_off_t offset, > xfs_off_t count); > + int > +xfs_reflink_end_atomic_cow(struct xfs_inode *ip, xfs_off_t offset, > + xfs_off_t count); > extern int xfs_reflink_recover_cow(struct xfs_mount *mp); > extern loff_t xfs_reflink_remap_range(struct file *file_in, loff_t pos_in, > struct file *file_out, loff_t pos_out, loff_t len, > -- > 2.31.1 > >