fs/nfs/nfs4state.c does not yet have any dprintk() call sites, and I'm
about to introduce some.  We will need a new flag for enabling them.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

To ensure that we don't reuse their identifiers.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Retest the RB_EMPTY_NODE() condition under the spin lock
to ensure that we don't call rb_erase() more than once on the
same state owner.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The NFSv4 spec is ambiguous about whether or not it is permissible
to reuse open owner names, so play it safe. This patch adds a timestamp
to the state_owner structure, and combines that with the IDA based
uniquifier.
Fixes a regression whereby the Linux server returns NFS4ERR_BAD_SEQID.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It is quite possible for the release_lockowner RPC call to race with the
close RPC call, in which case, we cannot dereference lsp->ls_state in
order to find the nfs_server.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Using user credentials for RENEW calls will fail when the user
credentials have expired.

To avoid this, try using the machine credentials when making RENEW
calls. If no machine credentials have been set, fall back to using user
credentials as before.
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Adding rate limit on `Lock reclaim failed` messages since it could fill
up system logs
Signed-off-by: NWilliam Dauchy <wdauchy@gmail.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Prevent the state manager from filling up system logs when recovery
fails on the server.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

Fix a number of "warning: symbol 'foo' was not declared. Should it be
static?" conditions.

Fix 2 cases of "warning: Using plain integer as NULL pointer"

fs/nfs/delegation.c:263:31: warning: restricted fmode_t degrades to integer
  - We want to allow upgrades to a WRITE delegation, but should otherwise
    consider servers that hand out duplicate delegations to be borken.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When the NFSv4.0 server tells us that it can no-longer talk to us
on the callback channel, we should attempt a new SETCLIENTID in
order to re-transmit the callback channel information.

Note that as long as we do not change the boot verifier, this is
a safe procedure; the server is required to keep our state.

Also move the function nfs_handle_cb_pathdown to fs/nfs/nfs4state.c,
and change the name in order to mark it as being specific to NFSv4.0.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that we select delegation stateids first, then
lock stateids and then open stateids.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Otherwise we can end up with sequence id problems if the client reuses
the owner_id before the server has processed the release_lockowner
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Handle DS READ and WRITE stateid errors by recovering the stateid on the MDS.

NFS4ERR_OLD_STATEID is ignored as the client always sends a
state sequenceid of zero for DS READ and WRITE stateids.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Replace the union with the common struct stateid4 as defined in both
RFC3530 and RFC5661. This makes it easier to access the sequence id,
which will again make implementing support for parallel OPEN calls
easier.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

It is really a function for selecting the correct stateid to use in a
read or write situation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we know that the delegation stateid is bad or revoked, we need to
remove that delegation as soon as possible, and then mark all the
stateids that relied on that delegation for recovery. We cannot use
the delegation as part of the recovery process.

Also note that NFSv4.1 uses a different error code (NFS4ERR_DELEG_REVOKED)
to indicate that the delegation was revoked.

Finally, ensure that setlk() and setattr() can both recover safely from
a revoked delegation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

A migration event will replace the rpc_xprt used by an rpc_clnt.  To
ensure this can be done safely, all references to cl_xprt must now use
a form of rcu_dereference().

Special care is taken with rpc_peeraddr2str(), which returns a pointer
to memory whose lifetime is the same as the rpc_xprt.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
[ cel: fix lockdep splats and layering violations ]
[ cel: forward ported to 3.4 ]
[ cel: remove rpc_max_reqs(), add rpc_net_ns() ]
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

To ensure that we don't just reuse the bad delegation when we attempt to
recover the nfs4_state that received the bad stateid error.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

This patch addresses printks that have some context to show that they are
from fs/nfs/, but for the sake of consistency now start with NFS:
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Messages like "Got error -10052 from the server on DESTROY_SESSION. Session
has been destroyed regardless" can be confusing to users who aren't very
familiar with NFS.

NOTE: This patch ignores any printks() that start by printing __func__ - that
will be in a separate patch.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Store a pointer to the rpc_task in struct nfs_seqid so that we can wake up
only that request that is able to grab the lock after we've released it.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We have to ensure that the wake up from the waitqueue and the assignment
of xprt->snd_task are atomic. We can do this by assigning the snd_task
while under the waitqueue spinlock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

Again, We're unlikely to ever need more than 2^31 simultaneous lock
owners, so let's replace the custom allocator.

Now that there are no more users, we can also get rid of the custom
allocator code.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We're unlikely to ever need more than 2^31 simultaneous open owners,
so let's replace the custom allocator with the generic ida allocator.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

Servers have a finite amount of memory to store NFSv4 open and lock
owners.  Moreover, servers may have a difficult time determining when
they can reap their state owner table, thanks to gray areas in the
NFSv4 protocol specification.  Thus clients should be careful to reuse
state owners when possible.

Currently Linux is not too careful.  When a user has closed all her
files on one mount point, the state owner's reference count goes to
zero, and it is released.  The next OPEN allocates a new one.  A
workload that serially opens and closes files can run through a large
number of open owners this way.

When a state owner's reference count goes to zero, slap it onto a free
list for that nfs_server, with an expiry time.  Garbage collect before
looking for a state owner.  This makes state owners for active users
available for re-use.

Now that there can be unused state owners remaining at umount time,
purge the state owner free list when a server is destroyed.  Also be
sure not to reclaim unused state owners during state recovery.

This change has benefits for the client as well.  For some workloads,
this approach drops the number of OPEN_CONFIRM calls from the same as
the number of OPEN calls, down to just one.  This reduces wire traffic
and thus open(2) latency.  Before this patch, untarring a kernel
source tarball shows the OPEN_CONFIRM call counter steadily increasing
through the test.  With the patch, the OPEN_CONFIRM count remains at 1
throughout the entire untar.

As long as the expiry time is kept short, I don't think garbage
collection should be terribly expensive, although it does bounce the
clp->cl_lock around a bit.

[ At some point we should rationalize the use of the nfs_server
->destroy method. ]
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
[Trond: Fixed a garbage collection race and a few efficiency issues]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There's no longer a need to check the so_server field in the state
owner, because nowadays the RB tree we search for state owners
contains owners for that only server.

Make nfs4_find_state_owners_locked() use the same tree searching logic
as nfs4_insert_state_owner_locked().
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There are currently 2 places in the state recovery code, where we do not
take sufficient precautions before accessing the state->lock_states. In
both cases, we should be holding the state->state_lock.
Reported-by: NPascal Bouchareine <pascal@gandi.net>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, the code assumes that the SEQUENCE status bits are mutually
exclusive. They are not...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 2.6.34]

If we handled an error condition, then nfs4_recovery_handle_error should
return '0' so that the state recovery thread can continue.
Also ensure that nfs4_check_lease() continues to abort if we haven't got
any credentials by having it return ENOKEY (which is not handled).
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The NFSv4 spec does not specify that the server must repeat that error,
so in order to avoid having the delegations revoked, we should handle
it immediately.

Also note that NFS4ERR_CB_PATH_DOWN does in fact renew the lease...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

instead of path_get()/path_put(), we can just use nfs_sb_{,de}active()
to pin the superblock down.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

can be skipped if the "eir_server_scope" from the exchange_id proc differs from
previous calls.

Also, in the future server_scope will be useful for determining whether client
trunking is available
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Currently, the call to nfs4_schedule_session_recovery() will actually just
result in a test of the lease when what we really want is to force a
session reset.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

The following patch ensures that we do not get permanently trapped in
the RPC layer when trying to establish a new client id or session.
This again ensures that the state manager can finish in a timely
fashion when the last filesystem to reference the nfs_client exits.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If a server for some reason keeps sending NFS4ERR_DELAY errors, we can end
up looping forever inside nfs4_proc_create_session, and so the usual
mechanisms for detecting if the nfs_client is dead don't work.

Fix this by ensuring that we loop inside the nfs4_state_manager thread
instead.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>