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From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>,
	jane.chu@oracle.com, linux-xfs@vger.kernel.org,
	hch@infradead.org, dan.j.williams@intel.com,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 3/5] vfs: add a zero-initialization mode to fallocate
Date: Tue, 21 Sep 2021 09:31:43 +0100	[thread overview]
Message-ID: <YUmYbxW70Ub2ytOc@infradead.org> (raw)
In-Reply-To: <20210921004431.GO1756565@dread.disaster.area>

On Tue, Sep 21, 2021 at 10:44:31AM +1000, Dave Chinner wrote:
> I think this wants to be a behavioural modifier for existing
> operations rather than an operation unto itself. i.e. similar to how
> KEEP_SIZE modifies ALLOC behaviour but doesn't fundamentally alter
> the guarantees ALLOC provides userspace.
> 
> In this case, the change of behaviour over ZERO_RANGE is that we
> want physical zeros to be written instead of the filesystem
> optimising away the physical zeros by manipulating the layout
> of the file.

Yes.

> Then we have and API that looks like:
> 
> 	ALLOC		- allocate space efficiently
> 	ALLOC | INIT	- allocate space by writing zeros to it
> 	ZERO		- zero data and preallocate space efficiently
> 	ZERO | INIT	- zero range by writing zeros to it
> 
> Which seems to cater for all the cases I know of where physically
> writing zeros instead of allocating unwritten extents is the
> preferred behaviour of fallocate()....

Agreed.  I'm not sure INIT is really the right name, but I can't come
up with a better idea offhand.

  reply	other threads:[~2021-09-21  8:32 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-18  1:30 [PATCHSET RFC v2 jane 0/5] vfs: enable userspace to reset damaged file storage Darrick J. Wong
2021-09-18  1:30 ` [PATCH 1/5] dax: prepare pmem for use by zero-initializing contents and clearing poisons Darrick J. Wong
2021-09-18 16:54   ` riteshh
2021-09-20 17:22     ` Darrick J. Wong
2021-09-21  4:07       ` riteshh
2021-09-22 18:26         ` Darrick J. Wong
2021-09-22 19:47           ` riteshh
2021-09-22 20:26           ` Dan Williams
2021-09-21  8:34   ` Christoph Hellwig
2021-09-22 18:10     ` Darrick J. Wong
2021-09-18  1:30 ` [PATCH 2/5] iomap: use accelerated zeroing on a block device to zero a file range Darrick J. Wong
2021-09-18 16:55   ` riteshh
2021-09-21  8:29   ` Christoph Hellwig
2021-09-22 18:53     ` Darrick J. Wong
2021-09-21 22:33   ` Dave Chinner
2021-09-22 18:54     ` Darrick J. Wong
2021-09-18  1:31 ` [PATCH 3/5] vfs: add a zero-initialization mode to fallocate Darrick J. Wong
2021-09-18 16:58   ` riteshh
2021-09-20 17:52   ` Eric Biggers
2021-09-20 18:06     ` Darrick J. Wong
2021-09-21  0:44   ` Dave Chinner
2021-09-21  8:31     ` Christoph Hellwig [this message]
2021-09-22  2:16       ` Dan Williams
2021-09-22  2:38         ` Darrick J. Wong
2021-09-22  3:59           ` Dave Chinner
2021-09-22  4:13             ` Darrick J. Wong
2021-09-22  5:49               ` Dave Chinner
2021-09-22 21:27                 ` Darrick J. Wong
2021-09-23  0:02                   ` Darrick J. Wong
2021-09-23  0:44                     ` Darrick J. Wong
2021-09-23  1:42                     ` Dave Chinner
2021-09-23  2:43                       ` Dan Williams
2021-09-23  5:42                         ` Dan Williams
2021-09-23 22:54                           ` Dave Chinner
2021-09-24  1:18                             ` Dan Williams
2021-09-24  1:21                               ` Jane Chu
2021-09-24  1:35                                 ` Darrick J. Wong
2021-09-27 21:07                                   ` Dave Chinner
2021-09-27 21:57                                     ` Jane Chu
2021-09-28  0:08                                       ` Dan Williams
2021-09-22  5:28     ` riteshh
2021-09-18  1:31 ` [PATCH 4/5] xfs: implement FALLOC_FL_ZEROINIT_RANGE Darrick J. Wong
2021-09-18  1:31 ` [PATCH 5/5] ext4: " Darrick J. Wong
2021-09-18 17:07   ` riteshh
2021-09-20 18:11     ` Darrick J. Wong
2021-09-21  6:10       ` riteshh
2021-09-18 18:05 ` [PATCHSET RFC v2 jane 0/5] vfs: enable userspace to reset damaged file storage Dan Williams
2021-09-23  0:51 ` Darrick J. Wong
2021-09-23  1:17   ` Dan Williams

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