From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>,
Goldwyn Rodrigues <rgoldwyn@suse.de>,
Amir Goldstein <amir73il@gmail.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Steve French <smfrench@gmail.com>,
overlayfs <linux-unionfs@vger.kernel.org>,
Anna Schumaker <Anna.Schumaker@netapp.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: Re: [PATCH 3/3] ovl: Use splice_with_holes in copy_up
Date: Tue, 8 May 2018 06:02:42 +0200 [thread overview]
Message-ID: <20180508040242.GA19735@lst.de> (raw)
In-Reply-To: <20180507231646.GK10363@dastard>
On Tue, May 08, 2018 at 09:16:46AM +1000, Dave Chinner wrote:
> This sort of whacky undefined behaviour w.r.t. sparseness was the
> reason we were given at LSFMM for cp and rsync not implementing
> copy_file_range() - they could not control it according to the
> user's direction. Hence my suggestion that we need flags to
> specifically direct the behaviour of the syscall so that userspace
> will actually use it....
They can just use SEEK_HOLE/DATA and just copy the chunk they care
about. Especially as they already have the SEEK_HOLE/DATA logic
for the plain old copy anyway - that is the only thing they have
to create holes in the destination file to start with. Nevermind
that a file system with inline dedup will happily create holes for
them underneath.
next prev parent reply other threads:[~2018-05-08 3:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-03 15:26 [PATCH 0/3] Holey splice! copy_file_range() with holes Goldwyn Rodrigues
2018-05-03 15:26 ` [PATCH 1/3] Perform splice in copy_file_range if in/out SB are not same Goldwyn Rodrigues
2018-05-03 15:26 ` [PATCH 2/3] copy_file_range: splice with holes Goldwyn Rodrigues
2018-05-03 15:26 ` [PATCH 3/3] ovl: Use splice_with_holes in copy_up Goldwyn Rodrigues
2018-05-03 19:57 ` Amir Goldstein
2018-05-03 22:11 ` Dave Chinner
2018-05-04 1:29 ` Goldwyn Rodrigues
2018-05-05 23:16 ` Dave Chinner
2018-05-07 12:16 ` Christoph Hellwig
2018-05-07 23:16 ` Dave Chinner
2018-05-08 4:02 ` Christoph Hellwig [this message]
2018-05-08 10:06 ` Dave Chinner
2018-05-08 16:11 ` Goldwyn Rodrigues
2018-05-08 16:24 ` Christoph Hellwig
2018-05-07 18:50 ` Andreas Dilger
2018-05-04 1:29 ` Goldwyn Rodrigues
2018-05-04 1:31 ` Goldwyn Rodrigues
2018-05-04 6:18 ` Amir Goldstein
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