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From: Duncan <1i5t5.duncan@cox.net>
To: linux-btrfs@vger.kernel.org
Subject: Re: NMI from btrfs cron jobs in 3.11.6
Date: Wed, 13 Nov 2013 15:15:04 +0000 (UTC)	[thread overview]
Message-ID: <pan$4655$5629e47b$7d83e5a0$59910e71@cox.net> (raw)
In-Reply-To: 201311140145.29255.russell@coker.com.au

Russell Coker posted on Thu, 14 Nov 2013 01:45:29 +1100 as excerpted:

> It appears that running two scripts that create snapshots at the same
> time as a script that removes maybe 97 snapshots causes an NMI.

This is a known bug in 3.11 (and presumably earlier).  Snapshot 
manipulation concurrency evidently wasn't originally well considered, and 
either a recent regression triggered the problem or possibly it always 
existed and only recently was reported (I don't know either way, tho the 
btrfs devs might).

Either way, there's a patch both to address the problem and adding a 
regression test to the xfstests filesystem testing suite to catch future 
regressions, but it's too recent to be in 3.11 yet, and indeed, as of my 
update yesterday (3.12.0-03510-g9b66bfb), there hadn't yet been a btrfs 
pull in the 3.12 commit window yet either, so while 3.12 will likely get 
it, it's not there yet as of the above git snapshot.

If interested in more, check recent list threads for the bug report and 
proposed patch.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman


  reply	other threads:[~2013-11-13 15:15 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-13 14:45 NMI from btrfs cron jobs in 3.11.6 Russell Coker
2013-11-13 15:15 ` Duncan [this message]
2013-11-17 14:43   ` Russell Coker
2013-11-17 15:16     ` Marc MERLIN
2013-11-28 17:10       ` David Sterba
2013-11-28 17:37 ` David Sterba

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