- don't BUG_ON() when not SP4_NONE
 - calculate recv and send reserve sizes correctly

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Fixes a NULL-dereference on attempts to use MACH_CRED protection over
auth_sys.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The following call chain:
------------------------------------------------------------
nfs4_get_vfs_file
- nfsd_open
  - dentry_open
    - do_dentry_open
      - __get_file_write_access
        - get_write_access
          - return atomic_inc_unless_negative(&inode->i_writecount) ? 0 : -ETXTBSY;
------------------------------------------------------------

can result in the following state:
------------------------------------------------------------
struct nfs4_file {
...
  fi_fds = {0xffff880c1fa65c80, 0xffffffffffffffe6, 0x0},
  fi_access = {{
      counter = 0x1
    }, {
      counter = 0x0
    }},
...
------------------------------------------------------------

1) First time around, in nfs4_get_vfs_file() fp->fi_fds[O_WRONLY] is
NULL, hence nfsd_open() is called where we get status set to an error
and fp->fi_fds[O_WRONLY] to -ETXTBSY. Thus we do not reach
nfs4_file_get_access() and fi_access[O_WRONLY] is not incremented.

2) Second time around, in nfs4_get_vfs_file() fp->fi_fds[O_WRONLY] is
NOT NULL (-ETXTBSY), so nfsd_open() is NOT called, but
nfs4_file_get_access() IS called and fi_access[O_WRONLY] is incremented.
Thus we leave a landmine in the form of the nfs4_file data structure in
an incorrect state.

3) Eventually, when __nfs4_file_put_access() is called it finds
fi_access[O_WRONLY] being non-zero, it decrements it and calls
nfs4_file_put_fd() which tries to fput -ETXTBSY.
------------------------------------------------------------
...
     [exception RIP: fput+0x9]
     RIP: ffffffff81177fa9  RSP: ffff88062e365c90  RFLAGS: 00010282
     RAX: ffff880c2b3d99cc  RBX: ffff880c2b3d9978  RCX: 0000000000000002
     RDX: dead000000100101  RSI: 0000000000000001  RDI: ffffffffffffffe6
     RBP: ffff88062e365c90   R8: ffff88041fe797d8   R9: ffff88062e365d58
     R10: 0000000000000008  R11: 0000000000000000  R12: 0000000000000001
     R13: 0000000000000007  R14: 0000000000000000  R15: 0000000000000000
     ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  #9 [ffff88062e365c98] __nfs4_file_put_access at ffffffffa0562334 [nfsd]
 #10 [ffff88062e365cc8] nfs4_file_put_access at ffffffffa05623ab [nfsd]
 #11 [ffff88062e365ce8] free_generic_stateid at ffffffffa056634d [nfsd]
 #12 [ffff88062e365d18] release_open_stateid at ffffffffa0566e4b [nfsd]
 #13 [ffff88062e365d38] nfsd4_close at ffffffffa0567401 [nfsd]
 #14 [ffff88062e365d88] nfsd4_proc_compound at ffffffffa0557f28 [nfsd]
 #15 [ffff88062e365dd8] nfsd_dispatch at ffffffffa054543e [nfsd]
 #16 [ffff88062e365e18] svc_process_common at ffffffffa04ba5a4 [sunrpc]
 #17 [ffff88062e365e98] svc_process at ffffffffa04babe0 [sunrpc]
 #18 [ffff88062e365eb8] nfsd at ffffffffa0545b62 [nfsd]
 #19 [ffff88062e365ee8] kthread at ffffffff81090886
 #20 [ffff88062e365f48] kernel_thread at ffffffff8100c14a
------------------------------------------------------------

Cc: stable@vger.kernel.org
Signed-off-by: Harshula Jayasuriya <harshula@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Pull nfsd bugfixes from Bruce Fields:
 "Just three minor bugfixes"

* 'for-3.11' of git://linux-nfs.org/~bfields/linux:
  svcrdma: underflow issue in decode_write_list()
  nfsd4: fix minorversion support interface
  lockd: protect nlm_blocked access in nlmsvc_retry_blocked

You can turn on or off support for minorversions using e.g.

	echo "-4.2" >/proc/fs/nfsd/versions

However, the current implementation is a little wonky.  For example, the
above will turn off 4.2 support, but it will also turn *on* 4.1 support.

This didn't matter as long as we only had 2 minorversions, which was
true till very recently.

And do a little cleanup here.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Pull nfsd changes from Bruce Fields:
 "Changes this time include:

   - 4.1 enabled on the server by default: the last 4.1-specific issues
     I know of are fixed, so we're not going to find the rest of the
     bugs without more exposure.
   - Experimental support for NFSv4.2 MAC Labeling (to allow running
     selinux over NFS), from Dave Quigley.
   - Fixes for some delicate cache/upcall races that could cause rare
     server hangs; thanks to Neil Brown and Bodo Stroesser for extreme
     debugging persistence.
   - Fixes for some bugs found at the recent NFS bakeathon, mostly v4
     and v4.1-specific, but also a generic bug handling fragmented rpc
     calls"

* 'for-3.11' of git://linux-nfs.org/~bfields/linux: (31 commits)
  nfsd4: support minorversion 1 by default
  nfsd4: allow destroy_session over destroyed session
  svcrpc: fix failures to handle -1 uid's
  sunrpc: Don't schedule an upcall on a replaced cache entry.
  net/sunrpc: xpt_auth_cache should be ignored when expired.
  sunrpc/cache: ensure items removed from cache do not have pending upcalls.
  sunrpc/cache: use cache_fresh_unlocked consistently and correctly.
  sunrpc/cache: remove races with queuing an upcall.
  nfsd4: return delegation immediately if lease fails
  nfsd4: do not throw away 4.1 lock state on last unlock
  nfsd4: delegation-based open reclaims should bypass permissions
  svcrpc: don't error out on small tcp fragment
  svcrpc: fix handling of too-short rpc's
  nfsd4: minor read_buf cleanup
  nfsd4: fix decoding of compounds across page boundaries
  nfsd4: clean up nfs4_open_delegation
  NFSD: Don't give out read delegations on creates
  nfsd4: allow client to send no cb_sec flavors
  nfsd4: fail attempts to request gss on the backchannel
  nfsd4: implement minimal SP4_MACH_CRED
  ...

Pull NFS client updates from Trond Myklebust:
 "Feature highlights include:
   - Add basic client support for NFSv4.2
   - Add basic client support for Labeled NFS (selinux for NFSv4.2)
   - Fix the use of credentials in NFSv4.1 stateful operations, and add
     support for NFSv4.1 state protection.

  Bugfix highlights:
   - Fix another NFSv4 open state recovery race
   - Fix an NFSv4.1 back channel session regression
   - Various rpc_pipefs races
   - Fix another issue with NFSv3 auth negotiation

  Please note that Labeled NFS does require some additional support from
  the security subsystem.  The relevant changesets have all been
  reviewed and acked by James Morris."

* tag 'nfs-for-3.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (54 commits)
  NFS: Set NFS_CS_MIGRATION for NFSv4 mounts
  NFSv4.1 Refactor nfs4_init_session and nfs4_init_channel_attrs
  nfs: have NFSv3 try server-specified auth flavors in turn
  nfs: have nfs_mount fake up a auth_flavs list when the server didn't provide it
  nfs: move server_authlist into nfs_try_mount_request
  nfs: refactor "need_mount" code out of nfs_try_mount
  SUNRPC: PipeFS MOUNT notification optimization for dying clients
  SUNRPC: split client creation routine into setup and registration
  SUNRPC: fix races on PipeFS UMOUNT notifications
  SUNRPC: fix races on PipeFS MOUNT notifications
  NFSv4.1 use pnfs_device maxcount for the objectlayout gdia_maxcount
  NFSv4.1 use pnfs_device maxcount for the blocklayout gdia_maxcount
  NFSv4.1 Fix gdia_maxcount calculation to fit in ca_maxresponsesize
  NFS: Improve legacy idmapping fallback
  NFSv4.1 end back channel session draining
  NFS: Apply v4.1 capabilities to v4.2
  NFSv4.1: Clean up layout segment comparison helper names
  NFSv4.1: layout segment comparison helpers should take 'const' parameters
  NFSv4: Move the DNS resolver into the NFSv4 module
  rpc_pipefs: only set rpc_dentry_ops if d_op isn't already set
  ...

We now have minimal minorversion 1 support; turn it on by default.

This can still be turned off with "echo -4.1 >/proc/fs/nfsd/versions".

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

RFC 5661 allows a client to destroy a session using a compound
associated with the destroyed session, as long as the DESTROY_SESSION op
is the last op of the compound.

We attempt to allow this, but testing against a Solaris client (which
does destroy sessions in this way) showed that we were failing the
DESTROY_SESSION with NFS4ERR_DELAY, because we assumed the reference
count on the session (held by us) represented another rpc in progress
over this session.

Fix this by noting that in this case the expected reference count is 1,
not 0.

Also, note as long as the session holds a reference to the compound
we're destroying, we can't free it here--instead, delay the free till
the final put in nfs4svc_encode_compoundres.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

This case shouldn't happen--the administrator shouldn't really allow
other applications access to the export until clients have had the
chance to reclaim their state--but if it does then we should set the
"return this lease immediately" bit on the reply.  That still leaves
some small races, but it's the best the protocol allows us to do in the
case a lease is ripped out from under us....

Signed-off-by: J. Bruce Fields <bfields@redhat.com>