Add a refcount in order to ensure that the gss_auth doesn't disappear from
underneath us while we're freeing up GSS contexts.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

We should almost always be deferencing the rpc_auth struct by means of the
credential's cr_auth field instead of the rpc_clnt->cl_auth anyway. Fix up
that historical mistake, and remove the macro that propagated it.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

RPCSEC_GSS needs to be able to send NULL RPC calls to the server in order
to free up any remaining GSS contexts.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

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

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

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

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

Convert to the use of atomic bitops...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

Add a helper rpc_cred_init()
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Also do the same for gss_api operation tables.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

Does a NULL RPC call and returns a pointer to the resulting rpc_task. The
call may be either synchronous or asynchronous.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

See the FIXME: auth_flavors[] really needs a lock and module refcounting.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Fix a memory leak in gss_create() whereby the rpc credcache was not being
freed if the rpc_mkpipe() call failed.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

We want to set the unix_cred_cache.nextgc on the first call to
unx_create(), which should be when unix_auth.au_count === 1
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

The leak only affects the RPCSEC_GSS caches, since they are the only ones
that are dynamically allocated...
Rename the existing rpcauth_free_credcache() to rpcauth_clear_credcache()
in order to better describe its role, then add a new function
rpcauth_destroy_credcache() that actually frees the cache in addition to
clearing it out.

Also move the call to destroy the credcache in gss_destroy() to come before
the rpc upcall pipe is unlinked.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

This allows us to correctly deduce when we need to remove the pipe.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Add a dentry_ops with a d_delete() method in order to ensure that dentries
are removed as soon as the last reference is gone.

Clean up rpc_depopulate() so that it only removes files that were created
via rpc_populate().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

Currently, the downcall queue is tied to the struct gss_auth, which means
that different RPCSEC_GSS pseudoflavours must use different upcall pipes.
Add a list to struct rpc_inode that can be used instead.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

It used to be possible for an rpc.gssd daemon to stuff the RPC credential
cache for any rpc client simply by creating RPCSEC_GSS contexts and then
doing downcalls. In practice, no daemons ever made use of this feature.

Remove this feature now, since it will be impossible to figure out which
mechanism a given context actually matches if we enable more
than one gss mechanism to use the same upcall pipe.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

We're just as well off using the inode spinlock instead.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Cleans up an issue whereby rpcsec_gss uses the rpc_clnt->cl_auth. If we want
to be able to add several rpc_auths to a single rpc_clnt, then this abuse
must go.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Brian Behlendorf writes:

The root cause of the NFS hang we were observing appears to be a rare
deadlock between the kernel provided usermodehelper API and the linux NFS
client.  The deadlock can arise because both of these services use the
generic linux work queues.  The usermodehelper API run the specified user
application in the context of the work queue.  And NFS submits both cleanup
and reconnect work to the generic work queue for handling.  Normally this
is fine but a deadlock can result in the following situation.

  - NFS client is in a disconnected state
  - [events/0] runs a usermodehelper app with an NFS dependent operation,
    this triggers an NFS reconnect.
  - NFS reconnect happens to be submitted to [events/0] work queue.
  - Deadlock, the [events/0] work queue will never process the
    reconnect because it is blocked on the previous NFS dependent
    operation which will not complete.`

The solution is simply to run reconnect requests on rpciod.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

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

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

Ensures that an rpc_client always has the possibility to send asynchronous
RPC calls.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Instead of taking the mutex every time we just need to increment/decrement
rpciod_users, we can optmise by using atomic_inc_not_zero and
atomic_dec_and_test.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

The kref now does most of what cl_count + cl_user used to do. The only
remaining role for cl_count is to tell us if we are in a 'shutdown'
phase. We can provide that information using a single bit field instead
of a full atomic counter.

Also rename rpc_destroy_client() to rpc_close_client(), which reflects
better what its role is these days.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

Replace it with explicit calls to rpc_shutdown_client() or
rpc_destroy_client() (for the case of asynchronous calls).
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Its use is at best racy, and there is only one user (lockd), which has
additional locking that makes the whole thing redundant.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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

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

Use that to protect the rpc_clnt->cl_tasks list instead of using a global
lock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>