From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH][RESEND] vfs: allow /proc/PID/maps to get device from stat
Date: Thu, 8 Aug 2013 05:13:49 -0700
Message-ID: <20130808121349.GC5180@infradead.org>
References: <20130807195718.GC31381@wotan.suse.de>
 <20130807201826.GA23804@infradead.org>
 <20130807205146.GE2397@localhost.localdomain>
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Cc: Christoph Hellwig <hch@infradead.org>,
	Mark Fasheh <mfasheh@suse.de>, viro@ZenIV.linux.org.uk,
	linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
	Chris Mason <chris.mason@fusionio.com>,
	Andrew Vagin <avagin@gmail.com>
To: Josef Bacik <jbacik@fusionio.com>
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On Wed, Aug 07, 2013 at 04:51:46PM -0400, Josef Bacik wrote:
> Not possible, this will break other things as subvolumes have their own inode
> space, it will confuse applications that get multiples of an inode number for
> different devices with the same st_dev.  Each subvolume has it's own anonymous
> dev to segregate things.  Thanks,

Yes, it's the same old issue of btrfs volumes misbehaving, and the
solution is still the same as 5 years ago: make sure each subvolume
has it's own sb, vfsmount and gets automounted, similar to what nfs4
does for this case.