Re: wapbl module

[David Holland <dholland-tech%netbsd.org@localhost>]

On Thu, Sep 22, 2011 at 08:24:48AM -0700, Paul Goyette wrote:
 > It would appear that wapbl is only relevant for ffs file systems
 > (and in particular, only for ffs filesystems with a V2 superblock
 > format).
 > 
 > Yet the current modularization of wapbl is not "dependant" on the
 > ffs module.  (wapbl's required-list is empty.)

It would be the other way around. AIUI the non-ffs wapbl code is
supposed to provide "fs-independent" services to ffs, whatever those
are.

Nobody has ever particularly explained why there are so many wapbl
tentacles outside of ffs; it has more than softupdates did, and this
was always one of the big criticisms of softupdates.

I think it's supposed to be "reusable" fs block journaling code, but I
don't see it as likely to be useful for any other fs. Maybe an ext3
implementation based on the current ext2 implementation might be able
to use it; but in that case it would still more appropriately live in
sys/ufs/ufs.

-- 
David A. Holland
dholland%netbsd.org@localhost