From: Tycho Andersen <tycho.andersen@canonical.com>
To: linux-btrfs@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: confusing mountinfo output when bind-mounting files
Date: Mon, 21 Mar 2016 09:21:44 -0600 [thread overview]
Message-ID: <20160321152144.GL8544@smitten> (raw)
Hi all,
I'm seeing some strange behavior when bind mounting files from a btrfs
subvolume. Consider the output below:
root@criu2:/tmp# mount -o loop /tmp/tester.btrfs /tmp/dir1
root@criu2:/tmp# touch dir1/file
root@criu2:/tmp# sudo mount --bind dir1/file dir2/file
root@criu2:/tmp# grep "/tmp/dir" /proc/self/mountinfo
128 24 0:45 / /tmp/dir1 rw,relatime shared:107 - btrfs /dev/loop0 rw,space_cache,subvolid=5,subvol=/
129 24 0:45 /file /tmp/dir2/file rw,relatime shared:107 - btrfs /dev/loop0 rw,space_cache,subvolid=5,subvol=/file
root@criu2:/tmp# btrfs --version
btrfs-progs v4.4
root@criu2:/tmp# uname -a
Linux criu2 4.4.0-8-generic #23-Ubuntu SMP Wed Feb 24 20:45:30 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
The issue here is that the "subvol=" mount option for the target of the bind
mount is "/file" when no such subvolume actually exists. Is this
intended? It's confusing to say the least, but seems like a bug to me.
Tycho
next reply other threads:[~2016-03-21 15:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-21 15:21 Tycho Andersen [this message]
2016-03-21 17:22 ` confusing mountinfo output when bind-mounting files Chris Murphy
2016-03-21 17:29 ` Tycho Andersen
2016-03-21 17:51 ` Austin S. Hemmelgarn
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