Pull nfsd fixes from Chuck Lever:

 - Address three recently introduced regressions

* tag 'nfsd-6.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  NFSD: CREATE_SESSION must never cache NFS4ERR_DELAY replies
  SUNRPC: Revert 561141dd494382217bace4d1a51d08168420eace
  nfsd: Fix error cleanup path in nfsd_rename()

Scott reports an occasional scatterlist BUG that is triggered by the
RFC 8009 Kunit test, then says:

> Looking through the git history of the auth_gss code, there are various
> places where static buffers were replaced by dynamically allocated ones
> because they're being used with scatterlists.

Reported-by: Scott Mayhew <smayhew@redhat.com>
Fixes: 561141dd4943 ("SUNRPC: Use a static buffer for the checksum initialization vector")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Bugfixes:
   - Fix for an Oops in the NFSv4.2 listxattr handler
   - Correct an incorrect buffer size in listxattr
   - Fix for an Oops in the pNFS flexfiles layout
   - Fix a refcount leak in NFS O_DIRECT writes
   - Fix missing locking in NFS O_DIRECT
   - Avoid an infinite loop in pnfs_update_layout
   - Fix an overflow in the RPC waitqueue queue length counter
   - Ensure that pNFS I/O is also protected by TLS when xprtsec is
     specified by the mount options
   - Fix a leaked folio lock in the netfs read code
   - Fix a potential deadlock in fscache
   - Allow setting the fscache uniquifier in NFSv4
   - Fix an off by one in root_nfs_cat()
   - Fix another off by one in rpc_sockaddr2uaddr()
   - nfs4_do_open() can incorrectly trigger state recovery
   - Various fixes for connection shutdown

  Features and cleanups:
   - Ensure that containers only see their own RPC and NFS stats
   - Enable nconnect for RDMA
   - Remove dead code from nfs_writepage_locked()
   - Various tracepoint additions to track EXCHANGE_ID, GETDEVICEINFO,
     and mount options"

* tag 'nfs-for-6.9-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (29 commits)
  nfs: fix panic when nfs4_ff_layout_prepare_ds() fails
  NFS: trace the uniquifier of fscache
  NFS: Read unlock folio on nfs_page_create_from_folio() error
  NFS: remove unused variable nfs_rpcstat
  nfs: fix UAF in direct writes
  nfs: properly protect nfs_direct_req fields
  NFS: enable nconnect for RDMA
  NFSv4: nfs4_do_open() is incorrectly triggering state recovery
  NFS: avoid infinite loop in pnfs_update_layout.
  NFS: remove sync_mode test from nfs_writepage_locked()
  NFSv4.1/pnfs: fix NFS with TLS in pnfs
  NFS: Fix an off by one in root_nfs_cat()
  nfs: make the rpc_stat per net namespace
  nfs: expose /proc/net/sunrpc/nfs in net namespaces
  sunrpc: add a struct rpc_stats arg to rpc_create_args
  nfs: remove unused NFS_CALL macro
  NFSv4.1: add tracepoint to trunked nfs4_exchange_id calls
  NFS: Fix nfs_netfs_issue_read() xarray locking for writeback interrupt
  SUNRPC: increase size of rpc_wait_queue.qlen from unsigned short to unsigned int
  nfs: fix regression in handling of fsc= option in NFSv4
  ...

Yes, yes, I know the slab people were planning on going slow and letting
every subsystem fight this thing on their own.  But let's just rip off
the band-aid and get it over and done with.  I don't want to see a
number of unnecessary pull requests just to get rid of a flag that no
longer has any meaning.

This was mainly done with a couple of 'sed' scripts and then some manual
cleanup of the end result.

Link: https://lore.kernel.org/all/CAHk-=wji0u+OOtmAOD-5JV3SXcRJF___k_+8XNKmak0yd5vW1Q@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We want to be able to have our rpc stats handled in a per network
namespace manner, so add an option to rpc_create_args to specify a
different rpc_stats struct instead of using the one on the rpc_program.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Chain RDMA Writes that convey Write chunks onto the local Send
chain. This means all WRs for an RPC Reply are now posted with a
single ib_post_send() call, and there is a single Send completion
when all of these are done. That reduces both the per-transport
doorbell rate and completion rate.

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

Refactor to eventually enable svcrdma to post the Write WRs for each
RPC response using the same ib_post_send() as the Send WR (ie, as a
single WR chain).

svc_rdma_result_payload (originally svc_rdma_read_payload) was added
so that the upper layer XDR encoder could identify a range of bytes
to be possibly conveyed by RDMA (if a Write chunk was provided by
the client).

The purpose of commit f6ad77590a5d ("svcrdma: Post RDMA Writes while
XDR encoding replies") was to post as much of the result payload
outside of svc_rdma_sendto() as possible because svc_rdma_sendto()
used to be called with the xpt_mutex held.

However, since commit ca4faf543a33 ("SUNRPC: Move xpt_mutex into
socket xpo_sendto methods"), the xpt_mutex is no longer held when
calling svc_rdma_sendto(). Thus, that benefit is no longer an issue.

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

Reduce the doorbell and Send completion rates when sending RPC/RDMA
replies that have Reply chunks. NFS READDIR procedures typically
return their result in a Reply chunk, for example.

Instead of calling ib_post_send() to post the Write WRs for the
Reply chunk, and then calling it again to post the Send WR that
conveys the transport header, chain the Write WRs to the Send WR
and call ib_post_send() only once.

Thanks to the Send Queue completion ordering rules, when the Send
WR completes, that guarantees that Write WRs posted before it have
also completed successfully. Thus all Write WRs for the Reply chunk
can remain unsignaled. Instead of handling a Write completion and
then a Send completion, only the Send completion is seen, and it
handles clean up for both the Writes and the Send.

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

Since the RPC transaction's svc_rdma_send_ctxt will stay around for
the duration of the RDMA Write operation, the write_info structure
for the Reply chunk can reside in the request's svc_rdma_send_ctxt
instead of being allocated separately.

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

Eventually I'd like the server to post the reply's Send WR along
with any Write WRs using only a single call to ib_post_send(), in
order to reduce the NIC's doorbell rate.

To do this, add an anchor for a WR chain to svc_rdma_send_ctxt, and
refactor svc_rdma_send() to post this WR chain to the Send Queue. For
the moment, the posted chain will continue to contain a single Send
WR.

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