Bug#659111: Regarding NFSv4: Save the owner/group name string when doing open

[Jonathan Nieder <jrnieder@gmail.com>]

Greg KH wrote:

> This patch seems to violate Documentatin/stable_kernel_rules.txt,
> doesn't it?

If I remember correctly, it's possible to get it to about 300 lines
with context by backing out the internal API change and keeping an
extra, ignored argument to decode_getfattr() and decode_getfattr_attrs(). :)
So yeah, not simple enough for stable@.

The patch addresses the following (client-side) regression:

| Our home directories here are mounted over NFS4. When I log in to machine A
| and run
|
| vim
| :q
|
| and then log into machine B and do:
|
| vim
| :q
|
| I get E137: Viminfo file is not writable: /users/system/rtheys/.viminfo
|
| Every invocation of 'vim and :q' will trigger this.
|
| Explicitely doing a stat of the file fixes this.

Rik bisected it to v2.6.32-rc1~412^2~48^2~15 (NFSv4: Don't do idmapper
upcalls for asynchronous RPC calls, 2009-08-09).

I would be happy to see a more minimal patch to address this, though I
don't know of one.

Thanks,
Jonathan