Reading and writing works fine... but can't enable rename to work :-(
If debug enbled things looks like this:
files cfs-ruby # cat > mp/1.txt
rf_getattr(/1.txt)
  Checking for created file ... no.
  Checking if editor file...No.
Checking filetype ...    root.directory?(/1.txt)
    root.file?(/1.txt)
 nonexistant.
rf_mknod(/1.txt)
  Checking if it's opened ... no.
  Checking if an IFREG is requested ... yes.
  Checking if it's an editor file ...no.
  Checking if it's a file ...    root.file?(/1.txt)
 no.
  Checking if it's writable to ...    root.can_write?(/1.txt)
 yes.
rf_getattr(/1.txt)
  Checking for created file ... created.
rf_open(/1.txt)
  Checking if it's already open ... no.
Checking if an editor file is requested... no.
  Checking for a raw_opened file...     root.raw_open(/1.txt,...)
 yes.
11
rf_write(/1.txt)  Offset is 0
  Checking if file is open...  yes.
  Checking if it's opened for raw write... yes.
    root.raw_write(/1.txt,...)

rf_release(/1.txt)
  Checking for opened file ... yes.
  Checking if it's opened for raw write... yes.
    root.raw_close(/1.txt)
files cfs-ruby # ls mp
rf_getattr(/)
rf_getattr(/)
rf_getattr(/)
rf_readdir(/)
    root.contents(/)
1.txt
files cfs-ruby # mv mp/1.txt mp/2.txt
rf_getattr(/2.txt)
  Checking for created file ... no.
  Checking if editor file...No.
Checking filetype ...    root.directory?(/2.txt)
    root.file?(/2.txt)
 nonexistant.
rf_getattr(/1.txt)
  Checking for created file ... created.
rf_getattr(/2.txt)
  Checking for created file ... no.
  Checking if editor file...No.
Checking filetype ...    root.directory?(/2.txt)
    root.file?(/2.txt)
 nonexistant.
rf_getattr(/2.txt)
  Checking for created file ... no.
  Checking if editor file...No.
Checking filetype ...    root.directory?(/2.txt)
    root.file?(/2.txt)
 nonexistant.
rf_rename(/1.txt,/2.txt)
  Checking if /1.txt is file ...    root.file?(/1.txt)
 yes.
  Checking if we can delete /1.txt ...    root.can_delete?(/1.txt)
 yes.
  Checking if we can write to /2.txt ...    root.can_write?(/2.txt)
 yes.
  Copying.
    root.delete(/1.txt)
files cfs-ruby # ls mp
rf_getattr(/)
rf_getattr(/)
rf_getattr(/)
rf_readdir(/)
    root.contents(/)
files cfs-ruby #