fs not recognized when upgrading kernel from 2.4.18 to 2.4.20

[Shen Aaron-r62966]

Hi,

  Now my Embeded linux system is using the 2.4.18 kernel. And everything is ok including 
scaning the cramfs and jffs2 rootdisk.

  But after I upgrade the kernel to be 2.4.20 and merged my modification to it, the rootdisk 
will not be recognized correctly. For cramfs rootdisk, it will say "cramfs: wrong magic". And 
for jffs2 rootdisk, it will scan each eraseblock and finally says no block is formatted.

  I havn't modified any codes in linux/fs/ and they should work fine. So I suspect the function 
like "read_super" may not work for the old rootdisk? But I havn't seen any notice which says 
the "mkcramfs" and "mkjffs2" need to be rebuild.

  Anybody has such experience? Looking forward to your feedback....

  Thanks!

Best Regards!
Feng Shen (Aaron)