Re: [PATCH 3/3] block: implement (some of) fallocate for block devices

From	Christoph Hellwig <hch@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] block: implement (some of) fallocate for block devices
Date	2016-03-05 22:00 +0100
Message-ID	<r9rsR-3cU-9@gated-at.bofh.it> (permalink)
References	<r98Jz-6FF-3@gated-at.bofh.it> <r98Jz-6FF-1@gated-at.bofh.it> <r9aLn-8jF-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, Mar 04, 2016 at 07:06:38PM -0800, Linus Torvalds wrote:
> > +       if ((mode & FALLOC_FL_PUNCH_HOLE) &&
> > +           (!blk_queue_discard(q) || !q->limits.discard_zeroes_data))
> > +               return -EOPNOTSUPP;
> 
> I'm ok with this, but suspect that some users would prefer to just
> turn this into ZERO_RANGE silently.
> 
> Comments from people who would be expected to use this?

A hole punch should be a hole punch, and not silently allocate blocks
isntead of deallocating them.  It's not even a fallback, it's pretty
much the opposite for some workloads.

Thread

[PATCH v6 0/3] fallocate for block devices to provide zero-out "Darrick J. Wong" <darrick.wong@oracle.com> - 2016-03-05 02:00 +0100
  [PATCH 3/3] block: implement (some of) fallocate for block devices "Darrick J. Wong" <darrick.wong@oracle.com> - 2016-03-05 02:00 +0100
    Re: [PATCH 3/3] block: implement (some of) fallocate for block devices Linus Torvalds <torvalds@linux-foundation.org> - 2016-03-05 04:10 +0100
      Re: [PATCH 3/3] block: implement (some of) fallocate for block  devices Christoph Hellwig <hch@infradead.org> - 2016-03-05 22:00 +0100
    Re: [PATCH 3/3] block: implement (some of) fallocate for block devices Linus Torvalds <torvalds@linux-foundation.org> - 2016-03-05 04:20 +0100
      Re: [PATCH 3/3] block: implement (some of) fallocate for block  devices Christoph Hellwig <hch@infradead.org> - 2016-03-05 22:00 +0100
  [PATCH 1/3] block: invalidate the page cache when issuing  BLKZEROOUT. "Darrick J. Wong" <darrick.wong@oracle.com> - 2016-03-05 02:00 +0100
    Re: [PATCH 1/3] block: invalidate the page cache when issuing  BLKZEROOUT. Christoph Hellwig <hch@infradead.org> - 2016-03-15 08:40 +0100
  [PATCH 2/3] block: require write_same and discard requests align to  logical block size "Darrick J. Wong" <darrick.wong@oracle.com> - 2016-03-05 02:00 +0100
    Re: [PATCH 2/3] block: require write_same and discard requests align  to logical block size Linus Torvalds <torvalds@linux-foundation.org> - 2016-03-05 04:10 +0100
    Re: [PATCH 2/3] block: require write_same and discard requests align  to logical block size Christoph Hellwig <hch@infradead.org> - 2016-03-15 08:40 +0100
  Re: [PATCH v6 0/3] fallocate for block devices to provide zero-out Linus Torvalds <torvalds@linux-foundation.org> - 2016-03-05 04:20 +0100

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