nfs cannot overwrite group writable files after 2.6.15

Hello people,

I have been running into this problem for a while now and it is
essentially preventing an upgrade from FC4 to FC5. This bug is also
known to exist in other distros and seems to be reproducable.

Client Distribution: Fedora Core 4
Server(s): Isilon cluster (modified FreeBSD), OS X Server (10.4.6)
Kernels tested:

2.6.15.1 --> 2.6.15.7 perform as expected
2.6.16.1 --> present group write operations fail with cannot open file
for writing

Test scenario

single nfs mounted folder /home

two users: testnfs1 (uid 0x0378) , testnfs2 (uid 0x0379)
Users are only in one primary group : users (gid 0x64)

testnfs1 own the folder /home/testnfs1

folder permissions are:
drwxrwxr-x 2 testnfs1 users 41 Nov 1 16:38 /home/testnfs1

testnfs1 creates a file in /home/testnfs1 called test file

permissions are:
-rw-rw-r-- 1 testnfs1 users 79 Nov 1 16:38 /home/testnfs1/testfile

testnfs2 edits the file and saves.

Results:
2.6.15 ---> file is overwritten as expected.
2.6.16.n ---> cannot open the file for writing.

Just to rule out the RPC 16 group limit I applied the > 16 group patch.
This had no effect on the results.

I have packet dumps of the two resulst but I cannot post them here.

Of course, /home mounted from a linux server always works as expected.

Does anyone have an idea as to what was changed with regards to nfs for
2.6.16? and even better how to fix this issue!

Thanks

James

On 6 Nov 2006 19:53:37 -0800, (E-Mail Removed) wrote:

>I have been running into this problem for a while now and it is
>essentially preventing an upgrade from FC4 to FC5. This bug is also
>known to exist in other distros and seems to be reproducable.

Nothing wrong with Slackware and NFS. Check your kernel options,
/etc/exports.

Grant.
--
http://bugsplatter.mine.nu/

Grant wrote:
> On 6 Nov 2006 19:53:37 -0800, (E-Mail Removed) wrote:
>
> >I have been running into this problem for a while now and it is
> >essentially preventing an upgrade from FC4 to FC5. This bug is also
> >known to exist in other distros and seems to be reproducable.
>
> Nothing wrong with Slackware and NFS. Check your kernel options,
> /etc/exports.
>
> Grant.
> --
> http://bugsplatter.mine.nu/

Client kernel options are as stock for FC4 and haven't been changed.

The key here is accessing BSD nfs servers (darwin and isilon) accessing
linux servers is fine. Versions of FreeBSD code after 5.5-RELEASE-p4
also are reported okay.

/etc/exports is wide open and works with every other client.

on the cluster:

/ifs -alldirs -maproot=root

and on the os x server

/var/tmp/shared -network 10.10.0.0 -mask 255.255.0.0 -maproot=root

I've been asking other people with the issue and they think it may be
the O_TRUNC patch as this is the last operation before everything
breaks.

I'm also chasing isilon to update their code but, hey, that could take
a while.

James.

(E-Mail Removed) wrote:
> Grant wrote:
> > On 6 Nov 2006 19:53:37 -0800, (E-Mail Removed) wrote:
> >
> > >I have been running into this problem for a while now and it is
> > >essentially preventing an upgrade from FC4 to FC5. This bug is also
> > >known to exist in other distros and seems to be reproducable.
> >
> > Nothing wrong with Slackware and NFS. Check your kernel options,
> > /etc/exports.
> >
> > Grant.
> > --
> > http://bugsplatter.mine.nu/
>
> Client kernel options are as stock for FC4 and haven't been changed.
>
> The key here is accessing BSD nfs servers (darwin and isilon) accessing
> linux servers is fine. Versions of FreeBSD code after 5.5-RELEASE-p4
> also are reported okay.
>
> /etc/exports is wide open and works with every other client.
>
> on the cluster:
>
> /ifs -alldirs -maproot=root
>
> and on the os x server
>
> /var/tmp/shared -network 10.10.0.0 -mask 255.255.0.0 -maproot=root
>
> I've been asking other people with the issue and they think it may be
> the O_TRUNC patch as this is the last operation before everything
> breaks.
>
> I'm also chasing isilon to update their code but, hey, that could take
> a while.
>
> James.

Thanks to Joerg Morbitzer for finding this:

http://www.kernel.org/git/?p=linux/k...c9da9aff1fa29b

These are the patches that need to be reversed to work with the older
BSD servers

James