From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>,
axboe@kernel.dk, kbusch@kernel.org, sagi@grimberg.me,
jejb@linux.ibm.com, martin.petersen@oracle.com,
djwong@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org,
chandan.babu@oracle.com, dchinner@redhat.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com,
linux-api@vger.kernel.org
Subject: Re: [PATCH 17/21] fs: xfs: iomap atomic write support
Date: Mon, 4 Dec 2023 16:39:12 +0100 [thread overview]
Message-ID: <20231204153912.GA3580@lst.de> (raw)
In-Reply-To: <a87d48a7-f2a8-40ae-8d9b-e4534ccc29b1@oracle.com>
On Mon, Dec 04, 2023 at 03:19:15PM +0000, John Garry wrote:
> On 04/12/2023 13:45, Christoph Hellwig wrote:
>> On Tue, Nov 28, 2023 at 05:42:10PM +0000, John Garry wrote:
>>> ok, fine, it would not be required for XFS with CoW. Some concerns still:
>>> a. device atomic write boundary, if any
>>> b. other FSes which do not have CoW support. ext4 is already being used for
>>> "atomic writes" in the field - see dubious amazon torn-write prevention.
>>
>> What is the 'dubious amazon torn-write prevention'?
>
> https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/storage-twp.html
>
> AFAICS, this is without any kernel changes, so no guarantee of unwanted
> splitting or merging of bios.
>
> Anyway, there will still be !CoW FSes which people want to support.
Ugg, so they badly reimplement NVMe atomic write support and use it
without software stack enablement. Calling it dubious is way to
gentle..
>> Relying just on the hardware seems very limited, especially as there is
>> plenty of hardware that won't guarantee anything larger than 4k, and
>> plenty of NVMe hardware without has some other small limit like 32k
>> because it doesn't support multiple atomicy mode.
>
> So what would you propose as the next step? Would it to be first achieve
> atomic write support for XFS with HW support + CoW to ensure contiguous
> extents (and without XFS forcealign)?
I think the very first priority is just block device support without
any fs enablement. We just need to make sure the API isn't too limited
for additional use cases.
> Ignoring FSes, then how is this supposed to work for block devices? We just
> always need HW support, right?
Yes.
next prev parent reply other threads:[~2023-12-04 15:39 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-29 10:27 [PATCH 00/21] block atomic writes John Garry
2023-09-29 10:27 ` [PATCH 01/21] block: Add atomic write operations to request_queue limits John Garry
2023-10-03 16:40 ` Bart Van Assche
2023-10-04 3:00 ` Martin K. Petersen
2023-10-04 17:28 ` Bart Van Assche
2023-10-04 18:26 ` Martin K. Petersen
2023-10-04 21:00 ` Bart Van Assche
2023-10-05 8:22 ` John Garry
2023-11-09 15:10 ` Christoph Hellwig
2023-11-09 17:01 ` John Garry
2023-11-10 6:23 ` Christoph Hellwig
2023-11-10 9:04 ` John Garry
2023-09-29 10:27 ` [PATCH 02/21] block: Limit atomic writes according to bio and queue limits John Garry
2023-11-09 15:13 ` Christoph Hellwig
2023-11-09 17:41 ` John Garry
2023-12-04 3:19 ` Ming Lei
2023-12-04 3:55 ` Ming Lei
2023-12-04 9:35 ` John Garry
2023-09-29 10:27 ` [PATCH 03/21] fs/bdev: Add atomic write support info to statx John Garry
2023-09-29 22:49 ` Eric Biggers
2023-10-01 13:23 ` Bart Van Assche
2023-10-02 9:51 ` John Garry
2023-10-02 18:39 ` Bart Van Assche
2023-10-03 0:28 ` Martin K. Petersen
2023-11-09 15:15 ` Christoph Hellwig
2023-10-03 1:51 ` Dave Chinner
2023-10-03 2:57 ` Darrick J. Wong
2023-10-03 7:23 ` John Garry
2023-10-03 15:46 ` Darrick J. Wong
2023-10-04 14:19 ` John Garry
2023-09-29 10:27 ` [PATCH 04/21] fs: Add RWF_ATOMIC and IOCB_ATOMIC flags for atomic write support John Garry
2023-10-06 18:15 ` Jeremy Bongio
2023-10-09 22:02 ` Dave Chinner
2023-09-29 10:27 ` [PATCH 05/21] block: Add REQ_ATOMIC flag John Garry
2023-09-29 10:27 ` [PATCH 06/21] block: Pass blk_queue_get_max_sectors() a request pointer John Garry
2023-09-29 10:27 ` [PATCH 07/21] block: Limit atomic write IO size according to atomic_write_max_sectors John Garry
2023-09-29 10:27 ` [PATCH 08/21] block: Error an attempt to split an atomic write bio John Garry
2023-09-29 10:27 ` [PATCH 09/21] block: Add checks to merging of atomic writes John Garry
2023-09-30 13:40 ` kernel test robot
2023-10-02 22:50 ` Nathan Chancellor
2023-10-04 11:40 ` John Garry
2023-09-29 10:27 ` [PATCH 10/21] block: Add fops atomic write support John Garry
2023-09-29 17:51 ` Bart Van Assche
2023-10-02 10:10 ` John Garry
2023-10-02 19:12 ` Bart Van Assche
2023-10-03 0:48 ` Martin K. Petersen
2023-10-03 16:55 ` Bart Van Assche
2023-10-04 2:53 ` Martin K. Petersen
2023-10-04 17:22 ` Bart Van Assche
2023-10-04 18:17 ` Martin K. Petersen
2023-10-05 17:10 ` Bart Van Assche
2023-10-05 22:36 ` Dave Chinner
2023-10-05 22:58 ` Bart Van Assche
2023-10-06 4:31 ` Dave Chinner
2023-10-06 17:22 ` Bart Van Assche
2023-10-07 1:21 ` Martin K. Petersen
2023-10-03 8:37 ` John Garry
2023-10-03 16:45 ` Bart Van Assche
2023-10-04 9:14 ` John Garry
2023-10-04 17:34 ` Bart Van Assche
2023-10-04 21:59 ` Dave Chinner
2023-12-04 2:30 ` Ming Lei
2023-12-04 9:27 ` John Garry
2023-12-04 12:18 ` Ming Lei
2023-12-04 13:13 ` John Garry
2023-12-05 1:45 ` Ming Lei
2023-12-05 10:49 ` John Garry
2023-09-29 10:27 ` [PATCH 11/21] fs: xfs: Don't use low-space allocator for alignment > 1 John Garry
2023-10-03 1:16 ` Dave Chinner
2023-10-03 3:00 ` Darrick J. Wong
2023-10-03 4:34 ` Dave Chinner
2023-10-03 10:22 ` John Garry
2023-09-29 10:27 ` [PATCH 12/21] fs: xfs: Introduce FORCEALIGN inode flag John Garry
2023-11-09 15:24 ` Christoph Hellwig
2023-09-29 10:27 ` [PATCH 13/21] fs: xfs: Make file data allocations observe the 'forcealign' flag John Garry
2023-10-03 1:42 ` Dave Chinner
2023-10-03 10:13 ` John Garry
2023-09-29 10:27 ` [PATCH 14/21] fs: xfs: Enable file data forcealign feature John Garry
2023-09-29 10:27 ` [PATCH 15/21] fs: xfs: Support atomic write for statx John Garry
2023-10-03 3:32 ` Dave Chinner
2023-10-03 10:56 ` John Garry
2023-10-03 16:10 ` Darrick J. Wong
2023-09-29 10:27 ` [PATCH 16/21] fs: iomap: Atomic write support John Garry
2023-10-03 4:24 ` Dave Chinner
2023-10-03 12:55 ` John Garry
2023-10-03 16:47 ` Darrick J. Wong
2023-10-04 1:16 ` Dave Chinner
2023-10-24 12:59 ` John Garry
2023-09-29 10:27 ` [PATCH 17/21] fs: xfs: iomap atomic " John Garry
2023-11-09 15:26 ` Christoph Hellwig
2023-11-10 10:42 ` John Garry
2023-11-28 8:56 ` John Garry
2023-11-28 13:56 ` Christoph Hellwig
2023-11-28 17:42 ` John Garry
2023-11-29 2:45 ` Martin K. Petersen
2023-12-04 13:45 ` Christoph Hellwig
2023-12-04 15:19 ` John Garry
2023-12-04 15:39 ` Christoph Hellwig [this message]
2023-12-04 18:06 ` John Garry
2023-12-05 4:55 ` Theodore Ts'o
2023-12-05 11:09 ` John Garry
2023-12-05 13:59 ` Ming Lei
2023-09-29 10:27 ` [PATCH 18/21] scsi: sd: Support reading atomic properties from block limits VPD John Garry
2023-09-29 17:54 ` Bart Van Assche
2023-10-02 11:27 ` John Garry
2023-10-06 17:52 ` Bart Van Assche
2023-10-06 23:48 ` Martin K. Petersen
2023-09-29 10:27 ` [PATCH 19/21] scsi: sd: Add WRITE_ATOMIC_16 support John Garry
2023-09-29 17:59 ` Bart Van Assche
2023-10-02 11:36 ` John Garry
2023-10-02 19:21 ` Bart Van Assche
2023-09-29 10:27 ` [PATCH 20/21] scsi: scsi_debug: Atomic write support John Garry
2023-09-29 10:27 ` [PATCH 21/21] nvme: Support atomic writes John Garry
[not found] ` <CGME20231004113943eucas1p23a51ce5ef06c36459f826101bb7b85fc@eucas1p2.samsung.com>
2023-10-04 11:39 ` Pankaj Raghav
2023-10-05 10:24 ` John Garry
2023-10-05 13:32 ` Pankaj Raghav
2023-10-05 15:05 ` John Garry
2023-11-09 15:36 ` Christoph Hellwig
2023-11-09 15:42 ` Matthew Wilcox
2023-11-09 15:46 ` Christoph Hellwig
2023-11-09 19:08 ` John Garry
2023-11-10 6:29 ` Christoph Hellwig
2023-11-10 8:44 ` John Garry
2023-09-29 14:58 ` [PATCH 00/21] block " Bart Van Assche
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