From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 1/1] xfs: use reflink to assist unaligned copy_file_range calls
Date: Mon, 7 Dec 2020 14:20:57 +0000 [thread overview]
Message-ID: <20201207142057.GA9865@infradead.org> (raw)
In-Reply-To: <20201206232154.GK629293@magnolia>
On Sun, Dec 06, 2020 at 03:21:54PM -0800, Darrick J. Wong wrote:
> On Tue, Dec 01, 2020 at 10:02:06AM +0000, Christoph Hellwig wrote:
> > On Mon, Nov 30, 2020 at 07:37:16PM -0800, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@oracle.com>
> > >
> > > Add a copy_file_range handler to XFS so that we can accelerate file
> > > copies with reflink when the source and destination ranges are not
> > > block-aligned. We'll use the generic pagecache copy to handle the
> > > unaligned edges and attempt to reflink the middle.
> >
> > Isn't this something we could better handle in the VFS (or a generic
> > helper) so that all file systems that support reflink could benefit?
>
> Maybe. I don't know if it's universally true that all filesystems
> should fall back to reflinking the middle range and pagecache copying
> the unaligned start/end.
>
> The other thing is that xfs can easily support reflink on rtextsize > 1,
> but that adds the requirement that we set i_blocksize to a larger value
> than we do now... or find some other way to convey allocation unit size
> to a generic version of the fallback. OTOH that's pretty easy to do
> from xfs_copy_file_range.
I think you can basically turn xfs_want_reflink_copy_range into a
callback supplied by the fs for the generic helper, and to deal with
the rtextsize problem just return the relevant block size from the
helper.
next prev parent reply other threads:[~2020-12-07 14:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 3:37 [PATCH 0/1] xfs: faster unaligned copy_file_range Darrick J. Wong
2020-12-01 3:37 ` [PATCH 1/1] xfs: use reflink to assist unaligned copy_file_range calls Darrick J. Wong
2020-12-01 10:02 ` Christoph Hellwig
2020-12-06 23:21 ` Darrick J. Wong
2020-12-07 14:20 ` Christoph Hellwig [this message]
2020-12-01 15:25 ` Brian Foster
2020-12-06 23:24 ` Darrick J. Wong
2020-12-07 14:01 ` Brian Foster
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