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From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: don't hand out pNFS layouts for reflink inodes
Date: Tue, 29 Mar 2016 09:21:28 +0200	[thread overview]
Message-ID: <20160329072128.GA14940@lst.de> (raw)
In-Reply-To: <20160328195140.GB5360@birch.djwong.org>

On Mon, Mar 28, 2016 at 12:51:40PM -0700, Darrick J. Wong wrote:
> >  	/*
> > +	 * The pNFS block layout spec actually supports reflink like
> > +	 * functionality, but the Linux pNFS server doesn't implement it yet.
> > +	 */
> > +	if (!xfs_is_reflink_inode(ip))
> > +		return -ENXIO;
> 
> /me isn't familiar with pNFS, but doesn't this make it so that
> xfs_fs_map_blocks /only/ works on reflinked files?  Maybe I'm misreading the
> comment, but it sounds to me like Linux doesn't support reflinked files over
> pNFS and therefore we want to disable this iomapping functionality any time we
> find a reflinked file.
> 
> But maybe there's a subtlety here that I'm missing?

You jsut missed me fat fingering the check :)

Btw, we'll need something similar to prevent swapfiles which just use
->bmap, but unfortunately swap just checks for the existences of method,
so I'll probably have to do some VFS changes to properly support that.

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  reply	other threads:[~2016-03-29  7:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-02 16:34 [PATCH] xfs: don't hand out pNFS layouts for reflink inodes Christoph Hellwig
2016-03-28 19:51 ` Darrick J. Wong
2016-03-29  7:21   ` Christoph Hellwig [this message]
2016-03-30  0:08     ` Darrick J. Wong
2016-03-30 17:26       ` Christoph Hellwig
2016-03-30 17:40         ` Darrick J. Wong

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