[Linux-cluster] Re: [PATCH 00/14] GFS

[David Teigland <teigland redhat com>]

On Fri, Aug 05, 2005 at 12:07:50PM +0200, J?rn Engel wrote:
> On Fri, 5 August 2005 17:44:52 +0800, David Teigland wrote:
> > Do we go a step beyond this and use say the crc32() function from
> > linux/crc32.h?  Is this _function_ as standard and unchanging as the table
> > of crcs?  In my tests it doesn't produce the same results as our
> > gfs2_disk_hash() function, even with both using the same crc table.  I
> > don't mind adopting a new function and just writing a user space
> > equivalent for the tools if it's a fixed standard.
> 
> The function is basically set in stone.  Variants exists depending on
> how it is called.  I know of four variants, but there may be more:
> 
> 1. Initial value is 0
> 2. Initial value is 0xffffffff
> a) Result is taken as-is
> b) Result is XORed with 0xffffffff
> 
> Maybe your code implements 1a, while you tried 2b with the lib/crc32.c
> function or something similar?

You're right, initial value 0xffffffff and xor result with 0xffffffff
matches the results from our function.  Great, we can get rid of
gfs2_disk_hash() and use crc32() directly.
Thanks,
Dave