NFS_LAYOUT_RETURN_BEFORE_CLOSE is being used to signal that a
layoutreturn is needed, either due to a layout recall or to a
layout error. Rename it to NFS_LAYOUT_RETURN_REQUESTED in order
to clarify its purpose.

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

* bugfixes:
  pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn
  pNFS/flexfiles: Improve merging of errors in LAYOUTRETURN

We must not skip encoding the statistics, or the server will see an
XDR encoding error.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # 4.0+

When we hit 22 errors, we start to overflow the memory buffers allocated
to the LAYOUTRETURN errors. The issue is that currently, RPC call reply
ordering determines how successful we are in merging errors that refer
to contiguous READ or WRITE requests.

Fix is to use an insertion sort to help detect contiguity.

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

* bugfixes:
  SUNRPC: Fixup socket wait for memory
  SUNRPC: Fix a missing break in rpc_anyaddr()
  pNFS/flexfiles: Fix an Oopsable typo in ff_mirror_match_fh()
  NFS: Fix attribute cache revalidation
  NFS: Ensure we revalidate attributes before using execute_ok()
  NFS: Flush reclaim writes using FLUSH_COND_STABLE
  NFS: Background flush should not be low priority
  NFSv4.1/pnfs: Fixup an lo->plh_block_lgets imbalance in layoutreturn
  NFSv4: Don't perform cached access checks before we've OPENed the file
  NFS: Allow the combination pNFS and labeled NFS
  NFS42: handle layoutstats stateid error
  nfs: Fix race in __update_open_stateid()
  nfs: fix missing assignment in nfs4_sequence_done tracepoint

* pnfs_generic:
  NFSv4.1/pNFS: Cleanup constify struct pnfs_layout_range arguments
  NFSv4.1/pnfs: Cleanup copying of pnfs_layout_range structures
  NFSv4.1/pNFS: Cleanup pnfs_mark_matching_lsegs_invalid()
  NFSv4.1/pNFS: Fix a race in initiate_file_draining()
  NFSv4.1/pNFS: pnfs_error_mark_layout_for_return() must always return layout
  NFSv4.1/pNFS: pnfs_mark_matching_lsegs_return() should set the iomode
  NFSv4.1/pNFS: Use nfs4_stateid_copy for copying stateids
  NFSv4.1/pNFS: Don't pass stateids by value to pnfs_send_layoutreturn()
  NFS: Relax requirements in nfs_flush_incompatible
  NFSv4.1/pNFS: Don't queue up a new commit if the layout segment is invalid
  NFS: Allow multiple commit requests in flight per file
  NFS/pNFS: Fix up pNFS write reschedule layering violations and bugs
  NFSv4: List stateid information in the callback tracepoints
  NFSv4.1/pNFS: Don't return NFS4ERR_DELAY unnecessarily in CB_LAYOUTRECALL
  NFSv4.1/pNFS: Ensure we enforce RFC5661 Section 12.5.5.2.1
  pNFS: If we have to delay the layout callback, mark the layout for return
  NFSv4.1/pNFS: Add a helper to mark the layout as returned
  pNFS: Ensure nfs4_layoutget_prepare returns the correct error

The flexfiles layout in particular, seems to want to poke around in the
O_DIRECT flags when retransmitting.
This patch sets up an interface to allow it to call back into O_DIRECT
to handle retransmission correctly. It also fixes a potential bug whereby
we could change the behaviour of O_DIRECT if an error is already pending.

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

Jeff reports seeing an Oops in ff_layout_alloc_lseg. Turns out
copy+paste has played cruel tricks on a nested loop.

Reported-by: Jeff Layton <jeff.layton@primarydata.com>
Cc: stable@vger.kernel.org # 4.3+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Currently, we will only record the layoutstats correctly if the
RPC call successfully obtains a slot. If we exit before that
happens, then we may find ourselves starting the busy timer through
the call in ff_layout_(read|write)_prepare_layoutstats, but never stopping it.

The same thing happens if we're doing DA-DS.

The fix is to ensure that we catch these cases in the rpc_release()
callback.

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

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