'Not a directory'

[Marcos Dione <mdione@grulic.org.ar>]

  I'm playing with a new fs developed by myself. I reached the stage
where I can mount the fs and even read the root's inode. but when I
try to cd into de mountpoint, chdir(2) complais that 'Not a directory'.

  doing a 'ls -l' I see that the mountpoint has the mode, dates and
size of the directory being mounted. the mode is 040755, so I don't
see the problem. also, using ramfs as reference, I note that the
directory is not inspected in any way, so I think that is not a
problem if I didn't developed the super, inode and file ops *yet*.

  also, I would *really* appreciate any link to any docs about
implementing filesystems for linux (e.g., what should all the *_ops
functions must do, return, etc., which should be reimplemented or
which could be ignored or even use the generic_* ones, and so on)

  best regards.