[linux-cifs-client] CIFS "POSIX" ACLs over the wire and DosAttrib xattr

[Steve French]

Made a start today at adding support for CIFS Posix ACLs over the wire 
and the 1st part is checked into bk://cifs.bkbits.net/linux-2.5cifs 

Noticed that Samba 3 smbclient has a getfacl option which sends the new 
level 0x204 (which Samba 3.0.9pre server rejected - need to check if 
they are things I have to add to smb.conf for this).  Looks pretty 
straightfoward to implement the rest of get in the cifs client so we 
should be able to display the acls soon (not sure what I want to do with 
cifs_permission yet though).

On the dos attrib front ... will probably also add support for the 
Samba4 layout (forgot to check whehter Samba3 uses the same layout) of 
the user.DosAttrib pseudo-xattr (simply returning info I already save in 
the cifs specific part of the inode struct).   Also made "os2." prefix a 
synoym for "user." prefix in xattrs (JFS displays xattrs from migrated 
os/2 volumes with the os2. prefix) - I strip them (os2 and user) both 
off before sending them to the server but am not planning on sending 
requests for "user.DosAttrib" over the wire).