[Cluster-devel] [GFS2 Patch] pass formal ino in do_filldir_main

[Wendy Cheng <wcheng@redhat.com>]

Steve,

I gave this issue some more thoughts - would like to suggest we take 
this patch (at least for now) since it aligns with current code base.

The no_formal_ino is apparently intented to get returned back to user 
space due to its unique-ness (and we have to trust pick_formal_ino() 
does its job right). With normal readdir system call, after the inode 
number is sent to user space, there is no route (I've checked) for it to 
come back to kernel. So the only user that would use these filldir ino 
inside the kernel is NFSD. NFSD calls gfs2_ilookup() that requires 
no_formal_ino.

If you look further... The current lookup code actually uses 
no_formal_ino, not no_addr. The two main "gate" routines that controls 
ino-to-inode conversion are:

* gfs2_ilookup() (used by NFS route)
* gfs2_inode_lookup() (used by VFS that calls gfs2_lookup()).

Both use no_formal_ino - gfs2_inode_lookup() logic hides this behind the 
little wrapper "gfs2_iget()". Since current VFS side's lookup has been 
working fine, this no_formal_ino idea apparently is working. So let's 
make NFSD side work the *same* way. I'm convinced this patch does a 
right thing.

I don't dispute using generation number may not be a bad idea and may 
perform better. However, if we really look into the details, it is not 
easy for current code structure. Since we have something already 
working, it is not wise to mess this code layout at this moment.

Make sense ?

-- Wendy