From: Ted Ts'o <tytso@mit.edu>
Subject: Re: Regular ext4 error warning with HD in USB dock
Date: Tue, 28 Dec 2010 09:15:16 -0500
Message-ID: <20101228141516.GH10149@thunk.org>
References: <201012280953.46149.kernel@kolivas.org>
 <20101228025343.GD10149@thunk.org>
 <20101228081917.GA1351@bitwizard.nl>
Mime-Version: 1.0
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Cc: Con Kolivas <kernel@kolivas.org>, linux-kernel@vger.kernel.org,
	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
	linux-usb@vger.kernel.org
To: Rogier Wolff <R.E.Wolff@bitwizard.nl>
Content-Disposition: inline
In-Reply-To: <20101228081917.GA1351@bitwizard.nl>
Sender: linux-ext4-owner@vger.kernel.org

On Tue, Dec 28, 2010 at 09:19:17AM +0100, Rogier Wolff wrote:
> > That's actually not an error.  It's a report which is generated every
> > 24 hours, indicating that there has been 3 errors since the last time
> > the error count has been cleared, with the first error taking place at
> > Sat Nov 6 10:27:57 2010 (US/Eastern) in the function
> > ext4_journal_start_sb(), at line 251, and the most recent error taking
> > place at Sat Nov 6 18:02:28 2010 (US/Eastern), in the function
> > ext4_put_super() at line 719.  This is a new feature which was added
> > in 2.6.36.
> 
> Nice. But the issue you're not mentioning is: What errors could have 
> happened on the 6th of november? Should Con worry about those errors?

It looks like those errors were probably caused by I/O errors while
writing to the journal.  Maybe due to a flakey USB connection,
perhaps?  It would be useful to look at the /var/log/messagfes around
that date to get a more detailed look.

> OK, the chances are that he has rebooted since november, and that an
> older fsck fixed the errors, but not cleared the "fs errror log". Would
> these errors have triggered a "remount-readonly" if the fs was mounted 
> like that?

Yes, errors that get recorded into the superblock are also errors that
would cause a read-only remount if the file system is set that way.

      	      			       	    - Ted