On May 16, 2023, at 3:23 PM, Jeff Layton [off-list ref] wrote:

On Tue, 2023-05-02 at 14:14 +0000, Chuck Lever III wrote:

quoted

quoted

On May 2, 2023, at 7:01 AM, Jiri Slaby [off-list ref] wrote:

On 08. 01. 23, 17:31, Chuck Lever wrote:

quoted

From: Chuck Lever <redacted>
To navigate around the space that svcauth_gss_accept() reserves
for the RPC payload body length and sequence number fields,
svcauth_gss_release() does a little dance with the reply's
accept_stat, moving the accept_stat value in the response buffer
down by two words.
Instead, let's have the ->accept() methods each set the proper
final location of the accept_stat to avoid having to move
things.

Hi,

I bisected to this (4bcf0343e8)

Assuming you did the bisect on the NFS server's kernel?

quoted

as it breaks nfs3-only servers in 6.3. I.e. /etc/nfs.conf containing:
[nfsd]
vers4=no

Note: Changing the settings in /etc/nfs.conf had no effect
on my server, so I effected the change by stopping the
server and poking values into /proc/fs/nfsd/versions by
hand.

Steve?

quoted

The client sees:
mount("10.0.2.15:/tmp", "/mnt", "nfs", 0, "vers=4.2,addr=10.0.2.15,clientad"...) = -1 EIO (Input/output error)
write(2, "mount.nfs: mount system call fai"..., 45
mount.nfs: mount system call failed for /mnt

And the kernel says:
nfs4_discover_server_trunking unhandled error -5. Exiting with error EIO

I reported in downstream as:
https://bugzilla.suse.com/show_bug.cgi?id=1210995

It cannot be reverted cleanly on the top of 6.3.

Any ideas?

I can reproduce a similar problem. Network capture shows
that the server is responding with NFS4ERR_NOENT to the
EXCHANGE_ID operation, and the client kernel log says:

quoted

nfs4_discover_server_trunking unhandled error -121. Exiting with error EIO

That's not the failure mode I expected given the commit
you bisected to, so it might not be the same problem you've
hit. I'll troubleshoot this and send a fix for testing.

Alex hit this problem in testing too, and I took a quick look.

In the attached capture, the client should have gotten back a
RPC_PROG_MISMATCH error, but the server has recorded an extra successful
accept state before encoding the RPC_PROG_MISMATCH error, leading to a
malformed reply.

I think that the problem is that encoding the accept status too early
means that we can't properly handle failures from the pg_init_request
call.

Chuck, any thoughts on how you'd like to handle this?

With this:

https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=nfsd-fixes&id=29cd2927fb914cc53b5ba4f67d2b74695c994ba4

I plan to send the fix to Linus tomorrow.


--
Chuck Lever