From: Nix <nix@esperi.org.uk>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: "Eric Sandeen" <sandeen@redhat.com>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
"J. Bruce Fields" <bfields@fieldses.org>,
"Bryan Schumaker" <bjschuma@netapp.com>,
"Peng Tao" <bergwolf@gmail.com>,
Trond.Myklebust@netapp.com, gregkh@linuxfoundation.org,
"Toralf Förster" <toralf.foerster@gmx.de>
Subject: Re: Apparent serious progressive ext4 data corruption bug in 3.6 (when rebooting during umount)
Date: Thu, 25 Oct 2012 00:42:44 +0100 [thread overview]
Message-ID: <87txtj77yj.fsf@spindle.srvr.nix> (raw)
In-Reply-To: <87y5iv78op.fsf_-_@spindle.srvr.nix> (nix@esperi.org.uk's message of "Thu, 25 Oct 2012 00:27:02 +0100")
On 25 Oct 2012, nix@esperi.org.uk said:
> Even though my own system relies on the possibility of rebooting during
> umount to reboot reliably, I'd be inclined to say 'not a bug, don't do
> that then' -- except that this renders it unreliable to use umount -l to
> unmount all the filesystems you can, skipping those that are not
> reachable due to having unresponsive servers in the way.
It's worse than that. If you're using filesystem namespaces, how can
*any* shell script loop, or anything in userspace, reliably unmount all
filesystems before reboot? It seems to me this is impossible. There is
no process that necessarily has access to all namespaces, and when you
bring PID namespaces into the picture there is no process that can even
kill all userspace processes in order to zap their filesystems.
I suspect we need a new blocking 'umountall' syscall and a command that
calls it, which umounts everything it can in every filesystem namespace
it can, skipping those that are (unreachable?) network mounts, and
returns only when everything is done. (Possibly it should first kill
every process it sees in every PID namespace other than that of the
caller, too.)
Then shutdown scripts can just call this, and get the right behaviour
immediately.
--
NULL && (void)
next prev parent reply other threads:[~2012-10-24 23:42 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-22 16:17 Heads-up: 3.6.2 / 3.6.3 NFS server panic: 3.6.2+ regression? Nix
2012-10-23 1:33 ` J. Bruce Fields
2012-10-23 14:07 ` Nix
2012-10-23 14:30 ` J. Bruce Fields
2012-10-23 16:32 ` Heads-up: 3.6.2 / 3.6.3 NFS server oops: 3.6.2+ regression? (also an unrelated ext4 data loss bug) Nix
2012-10-23 16:46 ` J. Bruce Fields
2012-10-23 16:54 ` J. Bruce Fields
2012-10-23 16:56 ` Myklebust, Trond
2012-10-23 16:56 ` Myklebust, Trond
2012-10-23 17:05 ` Nix
2012-10-23 17:36 ` Nix
2012-10-23 17:43 ` J. Bruce Fields
2012-10-23 17:44 ` Myklebust, Trond
2012-10-23 17:57 ` Myklebust, Trond
2012-10-23 17:57 ` Myklebust, Trond
[not found] ` <1351015039.4622.23.camel@lade.trondhjem.org>
2012-10-23 18:23 ` Myklebust, Trond
2012-10-23 18:23 ` Myklebust, Trond
2012-10-23 19:49 ` Nix
2012-10-24 10:18 ` [PATCH] lockd: fix races in per-net NSM client handling Stanislav Kinsbursky
[not found] ` <874nllxi7e.fsf_-_-AdTWujXS48Mg67Zj9sPl2A@public.gmane.org>
2012-10-23 20:57 ` Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?) Nix
2012-10-23 20:57 ` Nix
2012-10-23 22:19 ` Theodore Ts'o
2012-10-23 22:47 ` Nix
2012-10-23 23:16 ` Theodore Ts'o
2012-10-23 23:06 ` Nix
2012-10-23 23:28 ` Theodore Ts'o
2012-10-23 23:34 ` Nix
2012-10-24 0:57 ` Eric Sandeen
2012-10-24 20:17 ` Jan Kara
2012-10-26 15:25 ` Eric Sandeen
2012-10-24 19:13 ` Jannis Achstetter
2012-10-24 19:13 ` Jannis Achstetter
2012-10-24 21:31 ` Theodore Ts'o
2012-10-24 22:05 ` Jannis Achstetter
2012-10-24 23:47 ` Nix
2012-10-25 17:02 ` Felipe Contreras
2012-10-24 21:04 ` Jannis Achstetter
[not found] ` <87pq48nbyz.fsf_-_-AdTWujXS48Mg67Zj9sPl2A@public.gmane.org>
2012-10-24 1:13 ` Eric Sandeen
2012-10-24 1:13 ` Eric Sandeen
2012-10-24 4:15 ` Nix
2012-10-24 4:27 ` Eric Sandeen
2012-10-24 5:23 ` Theodore Ts'o
2012-10-24 7:00 ` Hugh Dickins
2012-10-24 11:46 ` Nix
2012-10-24 11:45 ` Nix
2012-10-24 17:22 ` Eric Sandeen
2012-10-24 19:49 ` Nix
2012-10-24 19:54 ` Nix
2012-10-24 20:30 ` Eric Sandeen
2012-10-24 20:34 ` Nix
2012-10-24 20:45 ` Nix
2012-10-24 21:08 ` Theodore Ts'o
2012-10-24 23:27 ` Apparent serious progressive ext4 data corruption bug in 3.6 (when rebooting during umount) Nix
2012-10-24 23:42 ` Nix [this message]
2012-10-25 1:10 ` Theodore Ts'o
2012-10-25 1:45 ` Nix
2012-10-25 1:45 ` Nix
2012-10-25 14:12 ` Theodore Ts'o
2012-10-25 14:15 ` Nix
2012-10-25 17:39 ` Nix
2012-10-25 11:06 ` Nix
2012-10-26 0:22 ` Apparent serious progressive ext4 data corruption bug in 3.6 (when rebooting during umount) (possibly blockdev / arcmsr at fault??) Nix
2012-10-26 0:11 ` Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?) Ric Wheeler
2012-10-26 0:43 ` Theodore Ts'o
2012-10-26 12:12 ` Nix
2012-10-26 20:35 ` Eric Sandeen
2012-10-26 20:37 ` Nix
[not found] ` <87wqydx957.fsf-AdTWujXS48Mg67Zj9sPl2A@public.gmane.org>
2012-10-26 20:56 ` Theodore Ts'o
2012-10-26 20:56 ` Theodore Ts'o
[not found] ` <20121026205618.GC8614-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2012-10-26 20:59 ` Nix
2012-10-26 20:59 ` Nix
[not found] ` <87objpx84k.fsf-AdTWujXS48Mg67Zj9sPl2A@public.gmane.org>
2012-10-26 21:15 ` Theodore Ts'o
2012-10-26 21:15 ` Theodore Ts'o
2012-10-26 21:19 ` Nix
[not found] ` <87haphx76u.fsf-AdTWujXS48Mg67Zj9sPl2A@public.gmane.org>
2012-10-27 0:22 ` Theodore Ts'o
2012-10-27 0:22 ` Theodore Ts'o
2012-10-27 12:45 ` Nix
2012-10-27 17:55 ` Theodore Ts'o
2012-10-27 18:47 ` Nix
2012-10-27 21:19 ` Eric Sandeen
2012-10-27 21:21 ` Nix
2012-10-27 21:23 ` Eric Sandeen
2012-10-27 21:29 ` Nix
2012-10-27 21:34 ` Eric Sandeen
2012-10-27 21:40 ` Nix
[not found] ` <09758CEA-74B5-48D0-8075-BB723A2CABBB@dilger.ca>
2012-10-29 2:09 ` Eric Sandeen
2012-10-27 22:42 ` Eric Sandeen
2012-10-29 1:00 ` Theodore Ts'o
2012-10-29 1:04 ` Nix
2012-10-29 2:24 ` Eric Sandeen
2012-10-29 2:34 ` Theodore Ts'o
2012-10-29 2:35 ` Eric Sandeen
2012-10-29 2:42 ` Theodore Ts'o
2012-10-27 18:30 ` Eric Sandeen
[not found] ` <20121026211542.GE8614-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org>
2012-10-27 3:11 ` Jim Rees
2012-10-27 3:11 ` Jim Rees
2012-10-27 8:01 ` Testing ext4's journal via simulating a reboot via KVM Theodore Ts'o
2012-10-28 4:23 ` [PATCH] ext4: fix unjournaled inode bitmap modification Eric Sandeen
2012-10-28 4:23 ` Eric Sandeen
2012-10-28 13:59 ` Nix
2012-10-29 2:30 ` [PATCH -v3] " Theodore Ts'o
2012-10-29 2:30 ` Theodore Ts'o
2012-10-29 3:24 ` Eric Sandeen
2012-10-29 5:07 ` Andreas Dilger
2012-10-29 17:08 ` Darrick J. Wong
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