Re: [PATCH] nilfs-utils: Work around uncleanable full filesystem

[Vyacheslav Dubeyko <slava-yeENwD64cLxBDgjK7y7TUQ@public.gmane.org>]

On Mon, 2013-01-14 at 16:54 +0100, Sven Eckelmann wrote:
> The filesystem can end up in a state were the filesystem is full and the
> returned ss_nongc_ctime is smaller than sui_lastmod of all reclaimable
> segments. The garbage collector will not clean anything and therefore no new
> room for new files will be available and ss_nongc_ctime/sui_lastmod will not be
> updated without using special tools. This makes the filesystem unusable without
> manual recovery.
> 
> Signed-off-by: Sven Eckelmann <sven-KaDOiPu9UxWEi8DpZVb4nw@public.gmane.org>
> --
> This problem appeared on a current 3.2 stable kernel (Debian Wheezy build). I
> am not an FS developer and have therefore not much background knowledge about
> the NILFS codebase. Nevertheless, this problem hit me quite hard after creating
> some files on a nilfs partition until it was full and deleting them again.
> 
> $ for i in `seq 0 150`; do dd if=/dev/zero of=foo$i count=22528; done
> $ rm foo*
> 
> Looking at the output debugging output using
> 
> $ watch -n .5 'df -h;tail /var/log/syslog;'
> 
> clearly showed that it was not finding any segments to delete. The only problem
> I could find was the threshold. After "removing" this threshold, I was able to
> get some clear segments again. I personally cannot explain why the check is
> there at all. Maybe there is a good reason but the comment above it didn't help
> much.
> 
> So, here for completeness the threshold: 1358164666 (aka: Mon Jan 14 12:57:46
> CET 2013)
> 

Unfortunately, currently, I can't reproduce the issue. All works fine on
my side.

Could you share more details about your environment? What version of
nilfs-utils do you use?

Maybe do you have some NILFS2-related error messages in your system log?

Or, maybe, reproducing path is more complex as you described?

With the best regards,
Vyacheslav Dubeyko.



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