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Date: Sat, 5 Mar 2016 12:58:34 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
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	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 3/3] block: implement (some of) fallocate for block
 devices
Message-ID: <20160305205833.GB4834@infradead.org>
References: <20160305005556.29738.66782.stgit@birch.djwong.org>
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 <CA+55aFzJW70YApg8ra-c79E-j1ujOXbh=26k2dvyYX+qZuu_8A@mail.gmail.com>
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On Fri, Mar 04, 2016 at 07:13:25PM -0800, Linus Torvalds wrote:
> > +       /* We can't change the bdev size from here */
> > +       if (!(mode & FALLOC_FL_KEEP_SIZE))
> > +               return -EOPNOTSUPP;
> 
> Oh, and this I think is wrong.
> 
> The thing is, FALLOC_FL_KEEP_SIZE is only supposed to matter if the
> region is outside the existing length.

For allocations...

> So if y ou punch a hole in the middle of a file, you don't need
> FALLOC_FL_KEEP_SIZE.

For FALLOC_FL_PUNCH_HOLE we always require FALLOC_FL_KEEP_SIZE so far,
and I'd rather not change things for block devices just because we can.