Re: [PATCH v1 26/27] SUNRPC: Set rq_accept_statp inside ->accept methods

[Jeff Layton <jlayton@kernel.org>]

On Tue, 2023-05-16 at 19:25 +0000, Chuck Lever III wrote:
> 
> > On May 16, 2023, at 3:23 PM, Jeff Layton <jlayton@kernel.org> wrote:
> > 
> > On Tue, 2023-05-02 at 14:14 +0000, Chuck Lever III wrote:
> > > 
> > > > On May 2, 2023, at 7:01 AM, Jiri Slaby <jirislaby@kernel.org> wrote:
> > > > 
> > > > On 08. 01. 23, 17:31, Chuck Lever wrote:
> > > > > From: Chuck Lever <chuck.lever@oracle.com>
> > > > > 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?
> > > 
> > > 
> > > > 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?
> > > 
> > > 
> > > > 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:
> > > 
> > > > 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.
> 
> 

Oh! I hadn't seen that cross the list. Did I miss it?
-- 
Jeff Layton <jlayton@kernel.org>