From: Jan Kara <jack@suse.cz>
To: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>, Mateusz Guzik <mguzik@redhat.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Josef Bacik <jbacik@fb.com>, Al Viro <viro@ZenIV.linux.org.uk>,
Eric Sandeen <esandeen@redhat.com>, Joe Perches <joe@perches.com>
Subject: Re: [PATCH V2 2/2] fs: print a message when freezing/unfreezing filesystems
Date: Thu, 15 May 2014 12:13:56 +0200 [thread overview]
Message-ID: <20140515101356.GC27289@quack.suse.cz> (raw)
In-Reply-To: <20140514223745.GF5421@dastard>
On Thu 15-05-14 08:37:45, Dave Chinner wrote:
> On Thu, May 15, 2014 at 08:00:52AM +1000, Dave Chinner wrote:
> > On Wed, May 14, 2014 at 01:39:45PM +0200, Jan Kara wrote:
> > > On Wed 14-05-14 13:26:21, Mateusz Guzik wrote:
> > > > On Wed, May 14, 2014 at 01:14:49PM +0200, Jan Kara wrote:
> > > > > On Wed 14-05-14 00:04:43, Mateusz Guzik wrote:
> > > > > > This helps hang troubleshooting efforts when only dmesg is available.
> > > > > >
> > > > > > While here remove code duplication with MS_RDONLY case and fix a
> > > > > > whitespace nit.
> > > > > I'm somewhat undecided here I have to say. On one hand I don't like
> > > > > printing to kernel log when everything is fine and kernel is operating
> > > > > normally. On the other hand I've seen quite a few cases where people have
> > > > > shot themselves in the foot with filesystem freezing so having some trace
> > > > > of this in the log doesn't seem like a completely bad thing either. What do
> > > > > other people think?
> > > > >
> > > >
> > > > I would like to note that the kernel already prints messages when e.g.
> > > > filesystems get mounted.
> > > Yeah, that's a fair point.
> >
> > But filesystems choose to output that info, not the VFS. When you do
> > a remount,ro there is no output in syslog, because filesystems don't
> > need to dump any output - the state change is reflected in
> > /proc/self/mounts. IMO frozen should state should be communicated
> > the same way so that it is silent when it just works, and the state
> > can easily be determined when something goes wrong.
>
> Say, like this:
>
> $ grep /mnt/test /proc/mounts
> /dev/vda /mnt/test xfs rw,relatime,attr2,inode64,noquota 0 0
> $ sudo xfs_freeze -f /mnt/test
> $ grep /mnt/test /proc/mounts
> /dev/vda /mnt/test xfs rw,frozen,relatime,attr2,inode64,noquota 0 0
> $ sudo xfs_freeze -u /mnt/test
> $ grep /mnt/test /proc/mounts
> /dev/vda /mnt/test xfs rw,relatime,attr2,inode64,noquota 0 0
> $
>
> Patch below does this.
Hum, same as Eric I'm not very enthusiastic about a fake mount option in
/proc/mounts. Maybe we could stuff some extra field in /proc/self/mountinfo?
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2014-05-15 10:14 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
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 [this message]
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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