Pull NFS client bugfixes from Trond Myklebust:

 - Fix SUNRPC call completion races with call_decode() that trigger a
   WARN_ON()

 - NFSv4.0 cannot support open-by-filehandle and NFS re-export

 - Revert "SUNRPC: Remove unreachable error condition" to allow handling
   of error conditions

 - Update suid/sgid mode bits after ALLOCATE and DEALLOCATE

* tag 'nfs-for-5.20-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  Revert "SUNRPC: Remove unreachable error condition"
  NFSv4.2: Update mode bits after ALLOCATE and DEALLOCATE
  NFSv4: Turn off open-by-filehandle and NFS re-export for NFSv4.0
  SUNRPC: Fix call completion races with call_decode()

The fallocate call invalidates suid and sgid bits as part of normal
operation. We need to mark the mode bits as invalid when using fallocate
with an suid so these will be updated the next time the user looks at them.

This fixes xfstests generic/683 and generic/684.

Reported-by: Yue Cui <cuiyue-fnst@fujitsu.com>
Fixes: 913eca1aea87 ("NFS: Fallocate should use the nfs4_fattr_bitmap")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

The NFSv4.0 protocol only supports open() by name. It cannot therefore
be used with open_by_handle() and friends, nor can it be re-exported by
knfsd.

Reported-by: Chuck Lever III <chuck.lever@oracle.com>
Fixes: 20fa19027286 ("nfs: add export operations")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Pull NFS client fixes from Trond Myklebust:
"Stable fixes:
   - NFS: Fix another fsync() issue after a server reboot

  Bugfixes:
   - NFS: unlink/rmdir shouldn't call d_delete() twice on ENOENT
   - NFS: Fix missing unlock in nfs_unlink()
   - Add sanity checking of the file type used by __nfs42_ssc_open
   - Fix a case where we're failing to set task->tk_rpc_status

  Cleanups:
   - Remove the NFS_CONTEXT_RESEND_WRITES flag that got obsoleted by the
     fsync() fix"

* tag 'nfs-for-5.20-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: RPC level errors should set task->tk_rpc_status
  NFSv4.2 fix problems with __nfs42_ssc_open
  NFS: unlink/rmdir shouldn't call d_delete() twice on ENOENT
  NFS: Cleanup to remove unused flag NFS_CONTEXT_RESEND_WRITES
  NFS: Remove a bogus flag setting in pnfs_write_done_resend_to_mds
  NFS: Fix another fsync() issue after a server reboot
  NFS: Fix missing unlock in nfs_unlink()

A destination server while doing a COPY shouldn't accept using the
passed in filehandle if its not a regular filehandle.

If alloc_file_pseudo() has failed, we need to decrement a reference
on the newly created inode, otherwise it leaks.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: ec4b092508982 ("NFS: inter ssc open")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs_unlink() calls d_delete() twice if it receives ENOENT from the
server - once in nfs_dentry_handle_enoent() from nfs_safe_remove and
once in nfs_dentry_remove_handle_error().

nfs_rmddir() also calls it twice - the nfs_dentry_handle_enoent() call
is direct and inside a region locked with ->rmdir_sem

It is safe to call d_delete() twice if the refcount > 1 as the dentry is
simply unhashed.
If the refcount is 1, the first call sets d_inode to NULL and the second
call crashes.

This patch guards the d_delete() call from nfs_dentry_handle_enoent()
leaving the one under ->remdir_sem in case that is important.

In mainline it would be safe to remove the d_delete() call.  However in
older kernels to which this might be backported, that would change the
behaviour of nfs_unlink().  nfs_unlink() used to unhash the dentry which
resulted in nfs_dentry_handle_enoent() not calling d_delete().  So in
older kernels we need the d_delete() in nfs_dentry_remove_handle_error()
when called from nfs_unlink() but not when called from nfs_rmdir().

To make the code work correctly for old and new kernels, and from both
nfs_unlink() and nfs_rmdir(), we protect the d_delete() call with
simple_positive().  This ensures it is never called in a circumstance
where it could crash.

Fixes: 3c59366c207e ("NFS: don't unhash dentry during unlink/rename")
Fixes: 9019fb391de0 ("NFS: Label the dentry with a verifier in nfs_rmdir() and nfs_unlink()")
Signed-off-by: NeilBrown <neilb@suse.de>
Tested-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Since pnfs_write_done_resend_to_mds() does not actually call
end_page_writeback() on the pages that are being redirected to the
metadata server, callers of fsync() do not see the I/O as complete until
the writeback to the MDS finishes. We therefore do not need to set
NFS_CONTEXT_RESEND_WRITES, since there is nothing to redrive.

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

Currently, when the writeback code detects a server reboot, it redirties
any pages that were not committed to disk, and it sets the flag
NFS_CONTEXT_RESEND_WRITES in the nfs_open_context of the file descriptor
that dirtied the file. While this allows the file descriptor in question
to redrive its own writes, it violates the fsync() requirement that we
should be synchronising all writes to disk.
While the problem is infrequent, we do see corner cases where an
untimely server reboot causes the fsync() call to abandon its attempt to
sync data to disk and causing data corruption issues due to missed error
conditions or similar.

In order to tighted up the client's ability to deal with this situation
without introducing livelocks, add a counter that records the number of
times pages are redirtied due to a server reboot-like condition, and use
that in fsync() to redrive the sync to disk.

Fixes: 2197e9b06c22 ("NFS: Fix up fsync() when the server rebooted")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add the missing unlock before goto.

Fixes: 3c59366c207e ("NFS: don't unhash dentry during unlink/rename")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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

  Stable fixes:
   - pNFS/flexfiles: Fix infinite looping when the RDMA connection
     errors out

  Bugfixes:
   - NFS: fix port value parsing
   - SUNRPC: Reinitialise the backchannel request buffers before reuse
   - SUNRPC: fix expiry of auth creds
   - NFSv4: Fix races in the legacy idmapper upcall
   - NFS: O_DIRECT fixes from Jeff Layton
   - NFSv4.1: Fix OP_SEQUENCE error handling
   - SUNRPC: Fix an RPC/RDMA performance regression
   - NFS: Fix case insensitive renames
   - NFSv4/pnfs: Fix a use-after-free bug in open
   - NFSv4.1: RECLAIM_COMPLETE must handle EACCES

  Features:
   - NFSv4.1: session trunking enhancements
   - NFSv4.2: READ_PLUS performance optimisations
   - NFS: relax the rules for rsize/wsize mount options
   - NFS: don't unhash dentry during unlink/rename
   - SUNRPC: Fail faster on bad verifier
   - NFS/SUNRPC: Various tracing improvements"

* tag 'nfs-for-5.20-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (46 commits)
  NFS: Improve readpage/writepage tracing
  NFS: Improve O_DIRECT tracing
  NFS: Improve write error tracing
  NFS: don't unhash dentry during unlink/rename
  NFSv4/pnfs: Fix a use-after-free bug in open
  NFS: nfs_async_write_reschedule_io must not recurse into the writeback code
  SUNRPC: Don't reuse bvec on retransmission of the request
  SUNRPC: Reinitialise the backchannel request buffers before reuse
  NFSv4.1: RECLAIM_COMPLETE must handle EACCES
  NFSv4.1 probe offline transports for trunking on session creation
  SUNRPC create a function that probes only offline transports
  SUNRPC export xprt_iter_rewind function
  SUNRPC restructure rpc_clnt_setup_test_and_add_xprt
  NFSv4.1 remove xprt from xprt_switch if session trunking test fails
  SUNRPC create an rpc function that allows xprt removal from rpc_clnt
  SUNRPC enable back offline transports in trunking discovery
  SUNRPC create an iterator to list only OFFLINE xprts
  NFSv4.1 offline trunkable transports on DESTROY_SESSION
  SUNRPC add function to offline remove trunkable transports
  SUNRPC expose functions for offline remote xprt functionality
  ...