From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: axboe@kernel.dk, brauner@kernel.org, djwong@kernel.org,
viro@zeniv.linux.org.uk, jack@suse.cz, dchinner@redhat.com,
hch@lst.de, cem@kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, hare@suse.de,
martin.petersen@oracle.com, catherine.hoang@oracle.com,
mcgrof@kernel.org, ritesh.list@gmail.com, ojaswin@linux.ibm.com
Subject: Re: [PATCH v7 5/8] xfs: Support FS_XFLAG_ATOMICWRITES
Date: Fri, 4 Oct 2024 14:35:20 +0200 [thread overview]
Message-ID: <20241004123520.GB19295@lst.de> (raw)
In-Reply-To: <20241004092254.3759210-6-john.g.garry@oracle.com>
On Fri, Oct 04, 2024 at 09:22:51AM +0000, John Garry wrote:
> Add initial support for new flag FS_XFLAG_ATOMICWRITES.
>
> This flag is a file attribute that mirrors an ondisk inode flag. Actual
> support for untorn file writes (for now) depends on both the iflag and the
> underlying storage devices, which we can only really check at statx and
> pwritev2() time. This is the same story as FS_XFLAG_DAX, which signals to
> the fs that we should try to enable the fsdax IO path on the file (instead
> of the regular page cache), but applications have to query STAT_ATTR_DAX to
> find out if they really got that IO path.
>
> Current kernel support for atomic writes is based on HW support (for atomic
> writes). Since for regular files XFS has no way to specify extent alignment
> or granularity, atomic write size is limited to the FS block size.
I'm still confused why this flag is needed for the current version
of this patch set. We should always be able to support atomic writes
<= block size if support by the block device.
next prev parent reply other threads:[~2024-10-04 12:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-04 9:22 [PATCH v7 0/8] block atomic writes for xfs John Garry
2024-10-04 9:22 ` [PATCH v7 1/8] block/fs: Pass an iocb to generic_atomic_write_valid() John Garry
2024-10-04 9:22 ` [PATCH v7 2/8] fs: Export generic_atomic_write_valid() John Garry
2024-10-04 9:22 ` [PATCH v7 3/8] fs/block: Check for IOCB_DIRECT in generic_atomic_write_valid() John Garry
2024-10-04 12:34 ` Christoph Hellwig
2024-10-04 12:45 ` John Garry
2024-10-04 9:22 ` [PATCH v7 4/8] fs: iomap: Atomic write support John Garry
2024-10-04 9:22 ` [PATCH v7 5/8] xfs: Support FS_XFLAG_ATOMICWRITES John Garry
2024-10-04 12:35 ` Christoph Hellwig [this message]
2024-10-04 13:07 ` John Garry
2024-10-07 5:42 ` Christoph Hellwig
2024-10-13 21:06 ` John Garry
2024-10-16 0:52 ` Darrick J. Wong
2024-10-04 9:22 ` [PATCH v7 6/8] xfs: Support atomic write for statx John Garry
2024-10-04 9:22 ` [PATCH v7 7/8] xfs: Validate atomic writes John Garry
2024-10-04 9:22 ` [PATCH v7 8/8] xfs: Support setting FMODE_CAN_ATOMIC_WRITE John Garry
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