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From: John Garry <[email protected]>
To: Kent Overstreet <[email protected]>,
	Dave Chinner <[email protected]>
Cc: Matthew Wilcox <[email protected]>,
	[email protected], [email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected]
Subject: Re: [PATCH v6 00/10] block atomic writes
Date: Fri, 5 Apr 2024 11:55:41 +0100	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <62uvkga54im76lnz47nc2znoeayidp2tcwpffseqtl42xdwxlc@hep6ckbgpwqz>

On 05/04/2024 11:20, Kent Overstreet wrote:
>>> The thing is that there's no requirement for an interface as complex as
>>> the one you're proposing here.  I've talked to a few database people
>>> and all they want is to increase the untorn write boundary from "one
>>> disc block" to one database block, typically 8kB or 16kB.
>>>
>>> So they would be quite happy with a much simpler interface where they
>>> set the inode block size at inode creation time, and then all writes to
>>> that inode were guaranteed to be untorn.  This would also be simpler to
>>> implement for buffered writes.
>> You're conflating filesystem functionality that applications will use
>> with hardware and block-layer enablement that filesystems and
>> filesystem utilities need to configure the filesystem in ways that
>> allow users to make use of atomic write capability of the hardware.
>>
>> The block layer functionality needs to export everything that the
>> hardware can do and filesystems will make use of. The actual
>> application usage and setup of atomic writes at the filesystem/page
>> cache layer is a separate problem.  i.e. The block layer interfaces
>> need only support direct IO and expose limits for issuing atomic
>> direct IO, and nothing more. All the more complex stuff to make it
>> "easy to use" is filesystem level functionality and completely
>> outside the scope of this patchset....
> A CoW filesystem can implement atomic writes without any block device
> support. It seems to me that might have been the easier place to start -
> start by getting the APIs right, then do all the plumbing for efficient
> untorn writes on non CoW filesystems...

03/10 and 04/10 in this series define the user API, i.e. RWF_ATOMIC and 
statx updates.

Any filesystem-specific changes - like in 
https://lore.kernel.org/linux-xfs/[email protected]/ 
- are just for enabling this API for that filesystem.

  reply	other threads:[~2024-04-05 10:57 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-26 13:38 [PATCH v6 00/10] block atomic writes John Garry
2024-03-26 13:38 ` [PATCH v6 01/10] block: Pass blk_queue_get_max_sectors() a request pointer John Garry
2024-04-10 22:58   ` Luis Chamberlain
2024-03-26 13:38 ` [PATCH v6 02/10] block: Call blkdev_dio_unaligned() from blkdev_direct_IO() John Garry
2024-04-10 22:53   ` Luis Chamberlain
2024-04-11  8:06     ` John Garry
2024-03-26 13:38 ` [PATCH v6 03/10] fs: Initial atomic write support John Garry
2024-03-26 13:38 ` [PATCH v6 04/10] fs: Add initial atomic write support info to statx John Garry
2024-03-26 13:38 ` [PATCH v6 05/10] block: Add core atomic write support John Garry
2024-03-26 17:11   ` Randy Dunlap
2024-04-10 23:34     ` Luis Chamberlain
2024-04-11  8:15       ` John Garry
2024-03-26 13:38 ` [PATCH v6 06/10] block: Add atomic write support for statx John Garry
2024-03-26 13:38 ` [PATCH v6 07/10] block: Add fops atomic write support John Garry
2024-03-26 13:38 ` [PATCH v6 08/10] scsi: sd: Atomic " John Garry
2024-03-26 13:38 ` [PATCH v6 09/10] scsi: scsi_debug: " John Garry
2024-03-26 13:38 ` [PATCH v6 10/10] nvme: " John Garry
2024-04-11  0:29   ` Luis Chamberlain
2024-04-11  8:59     ` John Garry
2024-04-11 16:22       ` Luis Chamberlain
2024-04-11 23:32         ` Dan Helmick
2024-03-27  3:50 ` [PATCH v6 00/10] block atomic writes Matthew Wilcox
2024-03-27 13:37   ` John Garry
2024-04-04 16:48     ` Matthew Wilcox
2024-04-05 10:06       ` John Garry
2024-04-08 17:50         ` Luis Chamberlain
2024-04-10  4:05           ` Matthew Wilcox
2024-04-10  6:20             ` Hannes Reinecke
2024-04-11  0:38               ` Luis Chamberlain
2024-04-14 20:50             ` Luis Chamberlain
2024-04-15 21:18               ` Matthew Wilcox
2024-04-16 21:11                 ` Luis Chamberlain
2024-04-10  8:34           ` John Garry
2024-04-11 19:07             ` Luis Chamberlain
2024-04-12  8:15               ` John Garry
2024-04-12 18:28                 ` Luis Chamberlain
2024-03-27 20:31   ` Dave Chinner
2024-04-05 10:20     ` Kent Overstreet
2024-04-05 10:55       ` John Garry [this message]
2024-04-05  6:14   ` Kent Overstreet

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