Why is there no JFS?

Darren Pilgrim dmp at pantherdragon.org
Fri Sep 24 08:53:24 PDT 2004


Matthew Emmerton wrote:
>>Thus spake Daxbert <daxbert_news at dweebsoft.com>:
>>
>>>The inspiration for this email was from a thread in
>>>-questions: "Re: fsck takes very long after crash/reset"
>>>
>>>Is anybody currently working on or does there exist
>>>a JFS for FreeBSD?
> 
> 
> Various people (including myself and Hiten Pandya) have done work to port
> the GPL'd JFS implementation, but there's one ugly problem -- the GPL.
> 
> We can make JFS into a kernel module (avoiding the static-link policy of the
> GPL), but then it can only (legally) be used on non-root filesystems, as the
> code to read the root filesystem must be statically linked into the kernel.
> This in itself makes JFS support somewhat pointless.

Not really.  A properly laid-out filesystem hierarchy will result in no 
writes to / (except for installworld/kernel).  That removes the problem 
that journalling addresses, and is probably why softupdates is disabled 
by default for /.  For large, active filesystems, journalling would be a 
big improvement when you had to run a foreground fsck.


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