Pull nfsd fix from Chuck Lever:

 - Fix another regression in the NFSD administrative API

* tag 'nfsd-6.7-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  nfsd: drop the nfsd_put helper

It's not safe to call nfsd_put once nfsd_last_thread has been called, as
that function will zero out the nn->nfsd_serv pointer.

Drop the nfsd_put helper altogether and open-code the svc_put in its
callers instead. That allows us to not be reliant on the value of that
pointer when handling an error.

Fixes: 2a501f55cd64 ("nfsd: call nfsd_last_thread() before final nfsd_put()")
Reported-by: Zhi Li <yieli@redhat.com>
Cc: NeilBrown <neilb@suse.de>
Signed-off-by: Jeffrey Layton <jlayton@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull nfsd fixes from Chuck Lever:

 - Address a few recently-introduced issues

* tag 'nfsd-6.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  SUNRPC: Revert 5f7fc5d69f6e92ec0b38774c387f5cf7812c5806
  NFSD: Revert 738401a9bd1ac34ccd5723d69640a4adbb1a4bc0
  NFSD: Revert 6c41d9a9bd0298002805758216a9c44e38a8500d
  nfsd: hold nfsd_mutex across entire netlink operation
  nfsd: call nfsd_last_thread() before final nfsd_put()

There's nothing wrong with this commit, but this is dead code now
that nothing triggers a CB_GETATTR callback. It can be re-introduced
once the issues with handling conflicting GETATTRs are resolved.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

For some reason, the wait_on_bit() in nfsd4_deleg_getattr_conflict()
is waiting forever, preventing a clean server shutdown. The
requesting client might also hang waiting for a reply to the
conflicting GETATTR.

Invoking wait_on_bit() in an nfsd thread context is a hazard. The
correct fix is to replace this wait_on_bit() call site with a
mechanism that defers the conflicting GETATTR until the CB_GETATTR
completes or is known to have failed.

That will require some surgery and extended testing and it's late
in the v6.7-rc cycle, so I'm reverting now in favor of trying again
in a subsequent kernel release.

This is my fault: I should have recognized the ramifications of
calling wait_on_bit() in here before accepting this patch.

Thanks to Dai Ngo <dai.ngo@oracle.com> for diagnosing the issue.

Reported-by: Wolfgang Walter <linux-nfs@stwm.de>
Closes: https://lore.kernel.org/linux-nfs/e3d43ecdad554fbdcaa7181833834f78@stwm.de/
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

This code is rarely (never?) enabled by distros, and it hasn't caught
anything in decades. Let's kill off this legacy debug code.

Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Rather than using svc_get() and svc_put() to hold a stable reference to
the nfsd_svc for netlink lookups, simply hold the mutex for the entire
time.

The "entire" time isn't very long, and the mutex is not often contented.

This makes way for us to remove the refcounts of svc, which is more
confusing than useful.

Reported-by: Jeff Layton <jlayton@kernel.org>
Closes: https://lore.kernel.org/linux-nfs/5d9bbb599569ce29f16e4e0eef6b291eda0f375b.camel@kernel.org/T/#u
Fixes: bd9d6a3efa97 ("NFSD: add rpc_status netlink support")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

If write_ports_addfd or write_ports_addxprt fail, they call nfsd_put()
without calling nfsd_last_thread().  This leaves nn->nfsd_serv pointing
to a structure that has been freed.

So remove 'static' from nfsd_last_thread() and call it when the
nfsd_serv is about to be destroyed.

Fixes: ec52361df99b ("SUNRPC: stop using ->sv_nrthreads as a refcount")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull nfsd fixes from Chuck Lever:

 - Fix several long-standing bugs in the duplicate reply cache

 - Fix a memory leak

* tag 'nfsd-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: Fix checksum mismatches in the duplicate reply cache
  NFSD: Fix "start of NFS reply" pointer passed to nfsd_cache_update()
  NFSD: Update nfsd_cache_append() to use xdr_stream
  nfsd: fix file memleak on client_opens_release

nfsd_cache_csum() currently assumes that the server's RPC layer has
been advancing rq_arg.head[0].iov_base as it decodes an incoming
request, because that's the way it used to work. On entry, it
expects that buf->head[0].iov_base points to the start of the NFS
header, and excludes the already-decoded RPC header.

These days however, head[0].iov_base now points to the start of the
RPC header during all processing. It no longer points at the NFS
Call header when execution arrives at nfsd_cache_csum().

In a retransmitted RPC the XID and the NFS header are supposed to
be the same as the original message, but the contents of the
retransmitted RPC header can be different. For example, for krb5,
the GSS sequence number will be different between the two. Thus if
the RPC header is always included in the DRC checksum computation,
the checksum of the retransmitted message might not match the
checksum of the original message, even though the NFS part of these
messages is identical.

The result is that, even if a matching XID is found in the DRC,
the checksum mismatch causes the server to execute the
retransmitted RPC transaction again.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>