From: Jannis Achstetter <jannis_achstetter@web.de>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?)
Date: Wed, 24 Oct 2012 23:04:50 +0200 [thread overview]
Message-ID: <508857F2.9000206@web.de> (raw)
In-Reply-To: <20121023221913.GC28626@thunk.org>
Am 24.10.2012 00:19, schrieb Theodore Ts'o:
> The reason why the problem happens rarely is that the effect of the
> buggy commit is that if the journal's starting block is zero, we fail
> to truncate the journal when we unmount the file system. This can
> happen if we mount and then unmount the file system fairly quickly,
> before the log has a chance to wrap. After the first time this has
> happened, it's not a disaster, since when we replay the journal, we'll
> just replay some extra transactions. But if this happens twice, the
> oldest valid transaction will still not have gotten updated, but some
> of the newer transactions from the last mount session will have gotten
> written by the very latest transacitons, and when we then try to do
> the extra transaction replays, the metadata blocks can end up getting
> very scrambled indeed.
Repost. Sorry, I don't mean to spam, I just don't see my first mail
(sent via gmane.org) anywhere, so ...
As a "normal linux user" I'm interested in the practical things to do
now to avoid data loss. I'm running several systems with 3.6.2 and ext4.
Fearing loss of data:
- Is there a way to see whether the journal of a specific partition has
been wrapped (since mounting) so that umounting and mounting (or doing a
reboot to downgrade the kernel) is safe?
- Is there a way to "force" a journal-wrap? Run any
filesystem-benchmark? Which one with what parameters? Or is it unwise
since I might even further corrupt data if I hit the case already?
- Is it wise to umount now and run e2fsck or might I corrupt my files
just by umounting now if the journal hasn't wrapped yet?
- How do you define "fairly quickly"? Of course servers run 24/7 but I
might be using my PC 2-5 hrs a day... Is that a "reboot to soon after
booting"?
- Any more advice you can give to the ordinary user to avoid
fs-corruption? Don't shut down machines for some days? Better down- or
upgrade the kernel?
Best regards,
Jannis Achstetter
next prev parent reply other threads:[~2012-10-24 21:04 UTC|newest]
Thread overview: 112+ 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 [this message]
[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
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
[not found] <jXsTo-5lW-13@gated-at.bofh.it>
[not found] ` <jXBDk-7vn-13@gated-at.bofh.it>
[not found] ` <jXNl8-5m5-13@gated-at.bofh.it>
[not found] ` <jXNOa-5MR-23@gated-at.bofh.it>
[not found] ` <jXPGh-87s-5@gated-at.bofh.it>
[not found] ` <jXTJW-4CH-55@gated-at.bofh.it>
[not found] ` <jXUZj-6mo-13@gated-at.bofh.it>
[not found] ` <jXVLH-7kO-5@gated-at.bofh.it>
[not found] ` <jXW53-7CC-5@gated-at.bofh.it>
[not found] ` <jXWeJ-7Lk-1@gated-at.bofh.it>
2012-10-24 17:38 ` Apparent serious progressive ext4 data corruption bug in 3.6.3 (and other stable branches?) Martin
2012-10-26 20:13 ` Martin
2012-10-26 20:24 ` Nix
2012-10-26 20:44 ` Martin
2012-10-26 20:47 ` Nix
2012-10-26 21:10 ` Theodore Ts'o
2012-10-26 23:15 ` Martin
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