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From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: John Garry <john.g.garry@oracle.com>,
	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, Alan Adamson <alan.adamson@oracle.com>
Subject: Re: [PATCH 21/21] nvme: Support atomic writes
Date: Thu, 9 Nov 2023 15:42:40 +0000	[thread overview]
Message-ID: <ZUz98KriiLsM8oQd@casper.infradead.org> (raw)
In-Reply-To: <20231109153603.GA2188@lst.de>

On Thu, Nov 09, 2023 at 04:36:03PM +0100, Christoph Hellwig wrote:
> Also I really want a check in the NVMe I/O path that any request
> with the atomic flag set actually adhers to the limits to at least
> partially paper over the annoying lack of a separate write atomic
> command in nvme.

That wasn't the model we had in mind.  In our thinking, it was fine to
send a write that crossed the atomic write limit, but the drive wouldn't
guarantee that it was atomic except at the atomic write boundary.
Eg with an AWUN of 16kB, you could send five 16kB writes, combine them
into a single 80kB write, and if the power failed midway through, the
drive would guarantee that it had written 0, 16kB, 32kB, 48kB, 64kB or
all 80kB.  Not necessarily in order; it might have written bytes 16-32kB,
64-80kB and not the other three.


  reply	other threads:[~2023-11-09 15:45 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
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 [this message]
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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