The NFSv4 and NFSv4.1 specs are both clear that the server should only check
stateid open mode if a SETATTR specifies the size attribute. If the
open mode is not one that allows writing, then it returns NFS4ERR_OPENMODE.

In the case where the SETATTR is not changing the size, the client will
still pass it the delegation stateid to ensure that the server does not
recall that delegation. In that case, the server should _ignore_ the
delegation open mode, and simply apply standard permission checks.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix up a conflict between the linux-next branch and mainline.
Conflicts:
	fs/nfs/nfs4proc.c

* rpcsec_gss-from_cel: (21 commits)
  NFS: Retry SETCLIENTID with AUTH_SYS instead of AUTH_NONE
  NFSv4: Don't clear the machine cred when client establish returns EACCES
  NFSv4: Fix issues in nfs4_discover_server_trunking
  NFSv4: Fix the fallback to AUTH_NULL if krb5i is not available
  NFS: Use server-recommended security flavor by default (NFSv3)
  SUNRPC: Don't recognize RPC_AUTH_MAXFLAVOR
  NFS: Use "krb5i" to establish NFSv4 state whenever possible
  NFS: Try AUTH_UNIX when PUTROOTFH gets NFS4ERR_WRONGSEC
  NFS: Use static list of security flavors during root FH lookup recovery
  NFS: Avoid PUTROOTFH when managing leases
  NFS: Clean up nfs4_proc_get_rootfh
  NFS: Handle missing rpc.gssd when looking up root FH
  SUNRPC: Remove EXPORT_SYMBOL_GPL() from GSS mech switch
  SUNRPC: Make gss_mech_get() static
  SUNRPC: Refactor nfsd4_do_encode_secinfo()
  SUNRPC: Consider qop when looking up pseudoflavors
  SUNRPC: Load GSS kernel module by OID
  SUNRPC: Introduce rpcauth_get_pseudoflavor()
  SUNRPC: Define rpcsec_gss_info structure
  NFS: Remove unneeded forward declaration
  ...

If we already checked the user access permissions on the original open,
then don't bother checking again on recovery. Doing so can cause a
deadlock with NFSv4.1, since the may_open() operation is not privileged.
Furthermore, we can't report an access permission failure here anyway.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we're in a delegation recall situation, we can't do a delegated open.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When we're doing open-by-filehandle in NFSv4.1, we shouldn't need to
do the cache consistency revalidation on the directory. It is
therefore more efficient to just use open_noattr, which returns the
file attributes, but not the directory attributes.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Recently I changed the SETCLIENTID code to use AUTH_GSS(krb5i), and
then retry with AUTH_NONE if that didn't work.  This was to enable
Kerberos NFS mounts to work without forcing Linux NFS clients to
have a keytab on hand.

Rick Macklem reports that the FreeBSD server accepts AUTH_NONE only
for NULL operations (thus certainly not for SETCLIENTID).  Falling
back to AUTH_NONE means our proposed 3.10 NFS client will not
interoperate with FreeBSD servers over NFSv4 unless Kerberos is
fully configured on both ends.

If the Linux client falls back to using AUTH_SYS instead for
SETCLIENTID, all should work fine as long as the NFS server is
configured to allow AUTH_SYS for SETCLIENTID.

This may still prevent access to Kerberos-only FreeBSD servers by
Linux clients with no keytab.  Rick is of the opinion that the
security settings the server applies to its pseudo-fs should also
apply to the SETCLIENTID operation.

Linux and Solaris NFS servers do not place that limitation on
SETCLIENTID.  The security settings for the server's pseudo-fs are
determined automatically as the union of security flavors allowed on
real exports, as recommended by RFC 3530bis; and the flavors allowed
for SETCLIENTID are all flavors supported by the respective server
implementation.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We should always clear it before initiating file recovery.
Also ensure that we clear it after a CLOSE and/or after TEST_STATEID fails.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

After a server reboot, the reclaimer thread will recover all the existing
locks. For locks that are blocked, however, it will change the value
of block->b_status to nlm_lck_denied_grace_period in order to signal that
they need to wake up and resend the original blocking lock request.

Due to a bug, however, the block->b_status never gets reset after the
blocked locks have been woken up, and so the process goes into an
infinite loop of resends until the blocked lock is satisfied.
Reported-by: NMarc Eshel <eshel@us.ibm.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

Defensive patch to ensure that we copy the state->open_stateid, which
can never be set to the delegation stateid.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Fix nfs4_select_rw_stateid() so that it chooses the open stateid
(or an all-zero stateid) if the delegation does not match the selected
read/write mode.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

RFC 3530 says that the seconds value of a nfstime4 structure is a 64bit
value, but we are instead sending a 32-bit 0 and then a 32bit conversion
of the 64bit Linux value.  This means that if we try to set atime to a
value before the epoch (touch -t 196001010101) the client will only send
part of the new value due to lost precision.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we're doing NFSv4.1 against a server that has persistent sessions,
then we should not need to call SETATTR in order to reset the file
attributes immediately after doing an exclusive create.

Note that since the create mode depends on the type of session that
has been negotiated with the server, we should not choose the
mode until after we've got a session slot.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This ensures that the RPC layer doesn't override the NFS session
negotiation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This is mainly for use by NFSv4.1, where the session negotiation
ultimately wants to decide how many RPC slots we can fill.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch ensures that we throttle new RPC requests if there are
requests already waiting in the xprt->backlog queue. The reason for
doing this is to fix livelock issues that can occur when an existing
(high priority) task is waiting in the backlog queue, gets woken up
by xprt_free_slot(), but a new task then steals the slot.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, _nfs4_do_setattr() will use the delegation stateid if no
writeable open file stateid is available.
If the server revokes that delegation stateid, then the call to
nfs4_handle_exception() will fail to handle the error due to the
lack of a struct nfs4_state, and will just convert the error into
an EIO.

This patch just removes the requirement that we must have a
struct nfs4_state in order to invalidate the delegation and
retry.
Reported-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Otherwise we deadlock if state recovery is initiated while we
sleep.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The second check was added in commit 65b62a29 but it will never be true.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Make sure that we set the status to 0 on success. Missed in testing
because it never appears when doing multiple mounts to _different_
servers.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: <stable@vger.kernel.org> # 3.7.x: 7b1f1fd1: NFSv4/4.1: Fix bugs in nfs4[01]_walk_client_list

Don't hold the NFSv4 sequence id while we check for open permission.
The call to ACCESS may block due to reboot recovery.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This will later allow NFS locking code to wait for readahead to complete
before releasing byte range locks.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When we send a RENEW or SEQUENCE operation in order to probe if the
lease is still valid, we want it to be able to time out since the
lease we are probing is likely to time out too. Currently, because
we use soft mount semantics for these RPC calls, the return value
is EIO, which causes the state manager to exit with an "unhandled
error" message.
This patch changes the call semantics, so that the RPC layer returns
ETIMEDOUT instead of EIO. We then have the state manager default to
a simple retry instead of exiting.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the state manager thread is already running, we may end up
racing with it in nfs_client_return_marked_delegations. Better to
just allow the state manager thread to do the job.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, if the application that holds the file open isn't doing
I/O, we may end up returning the delegation. This means that we can
no longer cache the file as aggressively, and often also that we
multiply the state that both the server and the client needs to track.

This patch adds a check for open files to the routine that scans
for delegations that are unreferenced.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Unify the error handling in nfs4_open_delegation_recall and
nfs4_lock_delegation_recall.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Make it symmetric with nfs4_lock_delegation_recall
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

All error cases are handled by the switch() statement, meaning that the
call to nfs4_handle_exception() is unreachable.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

A server shouldn't normally return NFS4ERR_GRACE if the client holds a
delegation, since no conflicting lock reclaims can be granted, however
the spec does not require the server to grant the open in this
instance
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

A server shouldn't normally return NFS4ERR_GRACE if the client holds a
delegation, since no conflicting lock reclaims can be granted, however
the spec does not require the server to grant the lock in this
instance.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

The Kconfig entry for SUNRPC_SWAP selects NETVM. That select statement
was added in commit a564b8f0 ("nfs:
enable swap on NFS"). But there's no Kconfig symbol NETVM. It apparently
was only in used in development versions of the swap over nfs
functionality but never entered mainline. Anyhow, it is a nop and can
safely be dropped.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The v4.1 callback thread has set_freezable() at the top, but it doesn't
ever try to freeze within the loop. Have it call try_to_freeze() at the
top of the loop. If a freeze event occurs, recheck kthread_should_stop()
after thawing.
Reported-by: NYanchuan Nian <ycnian@gmail.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the call to rpciod_up() fails, we currently leak a reference to the
struct rpc_xprt.
As part of the fix, we also remove the redundant check for xprt!=NULL.
This is already taken care of by the callers.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is unsafe to use list_for_each_entry_safe() here, because
when we drop the nn->nfs_client_lock, we pin the _current_ list
entry and ensure that it stays in the list, but we don't do the
same for the _next_ list entry. Use of list_for_each_entry() is
therefore the correct thing to do.

Also fix the refcounting in nfs41_walk_client_list().

Finally, ensure that the nfs_client has finished being initialised
and, in the case of NFSv4.1, that the session is set up.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Bryan Schumaker <bjschuma@netapp.com>
Cc: stable@vger.kernel.org [>= 3.7]

When we assign a new rpc_client to clp->cl_rpcclient, we need to destroy
the old one.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]

While testing error cases where rpc_new_client() fails, I saw
some oopses.

If rpc_new_client() fails, it already invokes xprt_put().  Thus
__rpc_clone_client() does not need to invoke it again.

Introduced by commit 1b63a751 "SUNRPC: Refactor rpc_clone_client()"
Fri Sep 14, 2012.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org [>=3.7]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The expected behaviour is that the client will decide at mount time
whether or not to use a krb5i machine cred, or AUTH_NULL.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Bryan Schumaker <bjschuma@netapp.com>