From: "Darrick J. Wong" <djwong@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Jane Chu <jane.chu@oracle.com>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 3/5] vfs: add a zero-initialization mode to fallocate
Date: Tue, 21 Sep 2021 19:38:01 -0700 [thread overview]
Message-ID: <20210922023801.GD570615@magnolia> (raw)
In-Reply-To: <CAPcyv4jF1UNW5rdXX3q2hfDcvzGLSnk=1a0C0i7_UjdivuG+pQ@mail.gmail.com>
On Tue, Sep 21, 2021 at 07:16:26PM -0700, Dan Williams wrote:
> On Tue, Sep 21, 2021 at 1:32 AM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > 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.
>
> FUA? As in, this is a forced-unit-access zeroing all the way to media
> bypassing any mechanisms to emulate zero-filled payloads on future
> reads.
FALLOC_FL_ZERO_EXISTING, because you want to zero the storage that
already exists at that file range?
--D
next prev parent reply other threads:[~2021-09-22 2:38 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
2021-09-22 2:16 ` Dan Williams
2021-09-22 2:38 ` Darrick J. Wong [this message]
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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