Ensure that pNFS flexfile allocations in rpciod/nfsiod callbacks can
fail in low memory mode, so that the threads don't block and loop
forever.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Assume that the higher layers will have set memalloc_nofs_save/restore
as appropriate.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Introduce a single tracepoint that can replace simple dprintk call
sites in upper layer "rpc_call_done" callbacks. Example:

   kworker/u24:2-1254  [001]   771.026677: rpc_stats_latency:    task:00000001@00000002 xid=0x16a6f3c0 rpcbindv2 GETPORT backlog=446 rtt=101 execute=555
   kworker/u24:2-1254  [001]   771.026677: rpc_task_call_done:   task:00000001@00000002 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpcb_getport_done
   kworker/u24:2-1254  [001]   771.026678: rpcb_setport:         task:00000001@00000002 status=0 port=20048

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

_nfs4_pnfs_v3/v4_ds_connect do
   some work
   smp_wmb
   ds->ds_clp = clp;

And nfs4_ff_layout_prepare_ds currently does
   smp_rmb
   if(ds->ds_clp)
      ...

This patch places the smp_rmb after the if. This ensures that following
reads only happen once nfs4_ff_layout_prepare_ds has checked that data
has been properly initialized.

Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Baptiste Lepers <baptiste.lepers@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

We (adam zabrocki, alexander matrosov, alexander tereshkin, maksym
bazalii) observed the check:

	if (fh->size > sizeof(struct nfs_fh))

should not use the size of the nfs_fh struct which includes an extra two
bytes from the size field.

struct nfs_fh {
	unsigned short         size;
	unsigned char          data[NFS_MAXFHSIZE];
}

but should determine the size from data[NFS_MAXFHSIZE] so the memcpy
will not write 2 bytes beyond destination.  The proposed fix is to
compare against the NFS_MAXFHSIZE directly, as is done elsewhere in fs
code base.

Fixes: d67ae825a59d ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Nikola Livic <nlivic@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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

  Features:

   - NFSv3: Add emulation of lookupp() to improve open_by_filehandle()
     support

   - A series of patches to improve readdir performance, particularly
     with large directories

   - Basic support for using NFS/RDMA with the pNFS files and flexfiles
     drivers

   - Micro-optimisations for RDMA

   - RDMA tracing improvements

  Bugfixes:

   - Fix a long standing bug with xs_read_xdr_buf() when receiving
     partial pages (Dan Aloni)

   - Various fixes for getxattr and listxattr, when used over non-TCP
     transports

   - Fixes for containerised NFS from Sargun Dhillon

   - switch nfsiod to be an UNBOUND workqueue (Neil Brown)

   - READDIR should not ask for security label information if there is
     no LSM policy (Olga Kornievskaia)

   - Avoid using interval-based rebinding with TCP in lockd (Calum
     Mackay)

   - A series of RPC and NFS layer fixes to support the NFSv4.2
     READ_PLUS code

   - A couple of fixes for pnfs/flexfiles read failover

  Cleanups:

   - Various cleanups for the SUNRPC xdr code in conjunction with the
     READ_PLUS fixes"

* tag 'nfs-for-5.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (90 commits)
  NFS/pNFS: Fix a typo in ff_layout_resend_pnfs_read()
  pNFS/flexfiles: Avoid spurious layout returns in ff_layout_choose_ds_for_read
  NFSv4/pnfs: Add tracing for the deviceid cache
  fs/lockd: convert comma to semicolon
  NFSv4.2: fix error return on memory allocation failure
  NFSv4.2/pnfs: Don't use READ_PLUS with pNFS yet
  NFSv4.2: Deal with potential READ_PLUS data extent buffer overflow
  NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow
  NFSv4.2: Handle hole lengths that exceed the READ_PLUS read buffer
  NFSv4.2: decode_read_plus_hole() needs to check the extent offset
  NFSv4.2: decode_read_plus_data() must skip padding after data segment
  NFSv4.2: Ensure we always reset the result->count in decode_read_plus()
  SUNRPC: When expanding the buffer, we may need grow the sparse pages
  SUNRPC: Cleanup - constify a number of xdr_buf helpers
  SUNRPC: Clean up open coded setting of the xdr_stream 'nwords' field
  SUNRPC: _copy_to/from_pages() now check for zero length
  SUNRPC: Cleanup xdr_shrink_bufhead()
  SUNRPC: Fix xdr_expand_hole()
  SUNRPC: Fixes for xdr_align_data()
  SUNRPC: _shift_data_left/right_pages should check the shift length
  ...

Don't bump the index twice.

Fixes: 563c53e73b8b ("NFS: Fix flexfiles read failover")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The callers of ff_layout_choose_ds_for_read() should decide whether or
not they want to return the layout on error. Sometimes, we may just want
to retry from the beginning.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull nfsd updates from Chuck Lever:
 "Several substantial changes this time around:

   - Previously, exporting an NFS mount via NFSD was considered to be an
     unsupported feature. With v5.11, the community has attempted to
     make re-exporting a first-class feature of NFSD.

     This would enable the Linux in-kernel NFS server to be used as an
     intermediate cache for a remotely-located primary NFS server, for
     example, even with other NFS server implementations, like a NetApp
     filer, as the primary.

   - A short series of patches brings support for multiple RPC/RDMA data
     chunks per RPC transaction to the Linux NFS server's RPC/RDMA
     transport implementation.

     This is a part of the RPC/RDMA spec that the other premiere
     NFS/RDMA implementation (Solaris) has had for a very long time, and
     completes the implementation of RPC/RDMA version 1 in the Linux
     kernel's NFS server.

   - Long ago, NFSv4 support was introduced to NFSD using a series of C
     macros that hid dprintk's and goto's. Over time, the kernel's XDR
     implementation has been greatly improved, but these C macros have
     remained and become fallow. A series of patches in this pull
     request completely replaces those macros with the use of current
     kernel XDR infrastructure. Benefits include:

       - More robust input sanitization in NFSD's NFSv4 XDR decoders.

       - Make it easier to use common kernel library functions that use
         XDR stream APIs (for example, GSS-API).

       - Align the structure of the source code with the RFCs so it is
         easier to learn, verify, and maintain our XDR implementation.

       - Removal of more than a hundred hidden dprintk() call sites.

       - Removal of some explicit manipulation of pages to help make the
         eventual transition to xdr->bvec smoother.

   - On top of several related fixes in 5.10-rc, there are a few more
     fixes to get the Linux NFSD implementation of NFSv4.2 inter-server
     copy up to speed.

  And as usual, there is a pinch of seasoning in the form of a
  collection of unrelated minor bug fixes and clean-ups.

  Many thanks to all who contributed this time around!"

* tag 'nfsd-5.11' of git://git.linux-nfs.org/projects/cel/cel-2.6: (131 commits)
  nfsd: Record NFSv4 pre/post-op attributes as non-atomic
  nfsd: Set PF_LOCAL_THROTTLE on local filesystems only
  nfsd: Fix up nfsd to ensure that timeout errors don't result in ESTALE
  exportfs: Add a function to return the raw output from fh_to_dentry()
  nfsd: close cached files prior to a REMOVE or RENAME that would replace target
  nfsd: allow filesystems to opt out of subtree checking
  nfsd: add a new EXPORT_OP_NOWCC flag to struct export_operations
  Revert "nfsd4: support change_attr_type attribute"
  nfsd4: don't query change attribute in v2/v3 case
  nfsd: minor nfsd4_change_attribute cleanup
  nfsd: simplify nfsd4_change_info
  nfsd: only call inode_query_iversion in the I_VERSION case
  nfs_common: need lock during iterate through the list
  NFSD: Fix 5 seconds delay when doing inter server copy
  NFSD: Fix sparse warning in nfs4proc.c
  SUNRPC: Remove XDRBUF_SPARSE_PAGES flag in gss_proxy upcall
  sunrpc: clean-up cache downcall
  nfsd: Fix message level for normal termination
  NFSD: Remove macros that are no longer used
  NFSD: Replace READ* macros in nfsd4_decode_compound()
  ...

Ensure that we report the correct netid when using UDP or RDMA
transports to the DSes.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>