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From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: xfs@oss.sgi.com
Subject: falloc vs reflink revisited
Date: Wed, 2 Mar 2016 07:50:07 -0800	[thread overview]
Message-ID: <20160302155007.GB7125@infradead.org> (raw)

Hi Darrick,

I know that I suggested unsharing blocks on fallocate, but it turns out
this is causing problems.  Applications expect falloc to be a fast
metadata operation, and copying a potentially large number of blocks
is against that expextation.  This is especially bad for the NFS
server, which should not be blocked for a long time in a synchronous
operation.

I think we'll have to remove the unshare and just fail the fallocate
for a reflinked region for now.  I still think it makes sense to expose
an unshare operation, and we probably should make that anyother
fallocate mode.

Opininions?

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             reply	other threads:[~2016-03-02 15:50 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-02 15:50 Christoph Hellwig [this message]
2016-03-02 16:42 ` falloc vs reflink revisited Darrick J. Wong
2016-03-30 18:27 ` fallocate mode flag for "unshare blocks"? Darrick J. Wong
2016-03-30 18:58   ` Austin S. Hemmelgarn
2016-03-31  7:58     ` Christoph Hellwig
2016-03-31 11:13       ` Austin S. Hemmelgarn
2016-03-31  0:32   ` Liu Bo
2016-03-31  7:55     ` Christoph Hellwig
2016-03-31 15:31       ` Andreas Dilger
2016-03-31 15:43         ` Austin S. Hemmelgarn
2016-03-31 16:47         ` Henk Slager
2016-03-31 11:18     ` Austin S. Hemmelgarn
2016-03-31 11:38       ` Austin S. Hemmelgarn
2016-03-31 19:52       ` Liu Bo
2016-03-31  1:18   ` Dave Chinner
2016-03-31  7:54     ` Christoph Hellwig
2016-03-31 11:18       ` Dave Chinner
2016-03-31 18:08         ` J. Bruce Fields
2016-03-31 18:19           ` Darrick J. Wong
2016-03-31 19:47           ` Andreas Dilger
2016-03-31 22:20             ` Dave Chinner
2016-03-31 22:34               ` J. Bruce Fields
2016-04-01  0:33                 ` Dave Chinner
2016-04-01  2:00                   ` J. Bruce Fields

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