From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 2/2] fs: print a message when freezing/unfreezing filesystems Date: Thu, 15 May 2014 08:47:25 -0400 Message-ID: <20140515124725.GA8194@thunk.org> References: <1400005862-3751-1-git-send-email-mguzik@redhat.com> <1400005862-3751-2-git-send-email-mguzik@redhat.com> <20140514215457.GC5421@dastard> <20140515094236.GE10637@mguzik.redhat.com> <20140515100157.GB27289@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Mateusz Guzik , Dave Chinner , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Josef Bacik , Al Viro , Eric Sandeen To: Jan Kara Return-path: Received: from imap.thunk.org ([74.207.234.97]:41684 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278AbaEOMre (ORCPT ); Thu, 15 May 2014 08:47:34 -0400 Content-Disposition: inline In-Reply-To: <20140515100157.GB27289@quack.suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, May 15, 2014 at 12:01:57PM +0200, Jan Kara wrote: > I was tracking down a couple of times what the hell is freezing the > filesystem (and not unfreezing it) and I agree with Mateusz it would be > nice if we could tell after the fact who froze the fs. Maybe we could store > that information in superblock and dump it during emergency thaw? Saving it in the superblock would require changing a bunch of file systems. What if we store this information in memory, and print it out under certain conditions (i.e., after a soft lockup detection, or upon request of some magic sysrq request)? Or we could create a tunable threshold and print a message after a file system has been frozen more than a particular specified duration, with that duration set conservatively to something like 60 or 120 seconds by default. - Ted