On Thu, Apr 07, 2011 at 11:05:42AM -0500, Amit Kulkarni wrote:
> >> Also, depending on the usage patterns, you might have a fs where high
> >> numbered inodes are used, while the fs itself is pretty empty. Filling
> >> up a fs with lots of files and them removing a lot of them is an
> >> example that could lead to such a situation. This diff does not speed
> >> things up in such cases.
> >
> > ...might have an impact in my case, since I often do things like rebuilding
> > the system including tons of packages on this machine, and that use case of
> > course perfectly matches what you say above. I think I'll remake these file
> > systems and run the test again just to satisfy my curiosity. But that'll
> > have to wait until after dinner. :-)
> >
> > Anyway, I see improvements both in memory usage and in speed, and I see no
> > obvoius malfunctions, so I'd say it's a go.
>
>
> Hi Otto,
>
> Comparing your diff with FreeBSD svn (not cvs, they dropped cvs! my
> bad on the initial comment) after Benny pointed this out.
>
> http://svn.freebsd.org/viewvc/base/head/sbin/fsck_ffs/pass1.c?revision=201708&view=markup
>
> Look at this comment inside the file
>
> /*
> * This optimization speeds up future runs of fsck
> * by trimming down the number of inodes in cylinder
> * groups that formerly had many inodes but now have
> * fewer in use.
> */
>
> and the commit entry by McKusick for rev 188110
>
> "Update the actions previously attempted by the -D option to make them
> robust. With these changes fsck is now able to detect and reliably
> rebuild corrupted cylinder group maps. The -D option is no longer
> necessary as it has been replaced by a prompt asking whether the
> corrupted cylinder group should be rebuilt and doing so when requested.
> These actions are only offered and taken when running fsck in manual
> mode. Corrupted cylinder groups found during preen mode cause the fsck
> to fail.
>
> Add the -r option to free up excess unused inodes. Decreasing the
> number of preallocated inodes reduces the running time of future
> runs of fsck and frees up space that can allocated to files. The -r
> option is ignored when running in preen mode."
> ------------------------------------------------------
>
> Will you please please please integrate that part of the code too!!!
> This is absolutely useful to have and is a fairly common situation. It
> will make fsck better and be a good way to partially defrag your fs.
>
> Or did you plan to keep that for later after more testing on this diff?
>
> Thanks,
> amit
Yes, I go step by step.
-Otto
