From: Dave Chinner <david@fromorbit.com>
To: Mateusz Guzik <mguzik@redhat.com>
Cc: "Lukáš Czerner" <lczerner@redhat.com>,
sandeen@redhat.com, "Jan Kara" <jack@suse.cz>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
"Josef Bacik" <jbacik@fb.com>,
"Al Viro" <viro@ZenIV.linux.org.uk>,
"Joe Perches" <joe@perches.com>
Subject: Re: [PATCH V2 2/2] fs: print a message when freezing/unfreezing filesystems
Date: Fri, 16 May 2014 08:51:41 +1000 [thread overview]
Message-ID: <20140515225141.GA26353@dastard> (raw)
In-Reply-To: <20140515223439.GA24089@mguzik.redhat.com>
On Fri, May 16, 2014 at 12:34:40AM +0200, Mateusz Guzik wrote:
> On Fri, May 16, 2014 at 08:21:35AM +1000, Dave Chinner wrote:
> > > IOW, a new column in mountinfo. For frozen filesystems it would contain
> > > 'frozen_by=[%s]:[%d]' (escaped comm, pid).
> >
> > I really don't see that the process that froze the filesystem is
> > particularly useful - it many cases that process is long gone (e.g.
> > fsfreeze is being used to allow a HW array to take a snapshot). Just
> > the fact it is in the process of freezing (if stuck, stack trace in
> > sysrq-w should be present) or frozen (freezing process may be long
> > gone, and is mostly irrelevant because you're now tracking down why
> > a thaw hasn't happened)...
>
> There are deamons which perform freezing and unfreezing on their own.
> Thus storing the name along with pid helps to determine whether someone
> went behind such daemon's back, or maybe it's the daemon which "forgot" to
> unfreeze after all.
Such a daemon should be logging the fact that it's freezing and
thawing the filesystem. The kernel is not the place to track what
buggy userspace applications are doing wrong.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2014-05-15 22:51 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-13 22:04 [PATCH V2 1/2] fs: include device name in error messages about freezing Mateusz Guzik
2014-05-13 22:04 ` [PATCH V2 2/2] fs: print a message when freezing/unfreezing filesystems Mateusz Guzik
2014-05-14 11:14 ` Jan Kara
2014-05-14 11:26 ` Mateusz Guzik
2014-05-14 11:39 ` Jan Kara
2014-05-14 22:00 ` Dave Chinner
2014-05-14 22:37 ` Dave Chinner
2014-05-14 22:40 ` Eric Sandeen
2014-05-15 10:40 ` Lukáš Czerner
2014-05-15 10:47 ` Mateusz Guzik
2014-05-15 22:21 ` Dave Chinner
2014-05-15 22:34 ` Mateusz Guzik
2014-05-15 22:51 ` Dave Chinner [this message]
2014-05-15 23:19 ` Mateusz Guzik
2014-05-16 0:11 ` Dave Chinner
2014-05-16 0:39 ` Mateusz Guzik
2014-05-19 9:43 ` Jan Kara
2014-05-19 23:37 ` Dave Chinner
2014-05-15 10:13 ` Jan Kara
2014-05-15 22:16 ` Dave Chinner
2014-05-14 11:58 ` Lukáš Czerner
2014-05-14 11:10 ` [PATCH V2 1/2] fs: include device name in error messages about freezing Jan Kara
2014-05-14 22:07 ` Dave Chinner
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