Otherwise, we cannot recover state correctly.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the server sends us an NFS4ERR_STALE_CLIENTID while the state management
thread is busy reclaiming state, we do want to treat all state that wasn't
reclaimed before the STALE_CLIENTID as if a network partition occurred (see
the edge conditions described in RFC3530 and RFC5661).
What we do not want to do is to send an nfs4_reclaim_complete(), since we
haven't yet even started reclaiming state after the server rebooted.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

flock locks want to be labelled using the process pid, while posix locks
want to be labelled using the fl_owner.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This is needed by NFSv4.0 servers in order to keep the number of locking
stateids at a manageable level.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The 'so_delegations' list appears to be unused.

Also eliminate so_client. If we already have so_server, we can get to the
nfs_client structure.
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>

We do not want to have the state recovery thread kick off and wait for a
memory reclaim, since that may deadlock when the writebacks end up
waiting for the state recovery thread to complete.

The safe thing is therefore to use GFP_NOFS in all open, close,
delegation return, lock, etc. operations that may be called by the
state recovery thread.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that we change the EXCHANGE_ID verifier (i.e. clp->cl_boot_time)
when we want to reset all state. This is mainly needed when the server
tells us that it is revoking our open or lock stateids.

Handle revoking of recallable state by expiring the delegations.

Handle callback path issues by expiring the delegations and then resetting
the session.
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>

Drain the fore channel and reset the max_slots to the new value.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If a KRB5 TGT ticket expires, we don't want to return an error
immediatel. If someone has a long running job and just forgets to run
"kinit" in time then this will make it fail.

Instead, we want to treat this situation as we would NFS4ERR_DELAY and
retry the upcall after delaying a bit with an exponential backoff.

This patch just makes any place that would handle NFS4ERR_DELAY also
handle -EKEYEXPIRED the same way. In the future, we may want to be more
sophisticated however and handle hard vs. soft mounts differently, or
specify some upper limit on how long we'll wait for a new TGT to be
acquired.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Even if the server is crazy, we should be able to mark the stateid as being
bad, to ensure it gets recovered.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>

Commit 5601a00d (nfs: run state manager
in privileged mode) introduces a regression in the NFSv4 code when
compiled with CONFIG_NFS_V4_1. The calls to nfs4_end_drain_session()
from the main loop in nfs4_state_manager() Oops due to the lack of an
NFSv4.1 session when running NFSv4.0.

The fix is to move those two calls back into nfs41_init_clientid() and
nfs4_reset_session().

The calls to nfs4_end_drain_session() that remain inside
nfs4_state_manager() are safe, since the NFSv4.0 code will never set the
NFS4CLNT_SESSION_DRAINING bit.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the CLOSE or OPEN_DOWNGRADE call triggers a state recovery, and has
to be resent, then we must release the seqid. Otherwise the open
recovery will wait for the close to finish, which causes a deadlock.

This is mainly a NFSv4.1 problem, although it can theoretically happen
with NFSv4.0 too, in a OPEN_DOWNGRADE situation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

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

The NFSv4.1 spec indicates RECLAIM_COMPLETE is to be issued
whenever a client establishes a new client id, not only after
detecting the server has rebooted.

Set the NFS4CLNT_RECLAIM_REBOOT bit after every new client id has
been established.  This enables us to issue RECLAIM_COMPLETE
during the wrap up of the NFS4CLNT_RECLAIM_REBOOT state.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The state manager was not marking the stateids as needing to be reclaimed
after reestablishing the clientid.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If CREATE_SESSION fails with NFS4ERR_STALE_CLIENTID, don't clear the
NFS4CLNT_SESSION_DRAINING flag and don't wake RPCs waiting for the
session to be reestablished.  We don't have a session yet, so there
is no reason to wake other RPCs.

This avoids sending spurious compounds with bogus sequenceID during
session and state recovery.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
[Trond.Myklebust@netapp.com: cleaned up patch by adding the
                             nfs41_begin/end_drain_session() helpers]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move call to get the lease time and the setup of the state
renewal out of nfs4_create_session so that it can be called
after clearing the DRAINING flag.  We use the getattr RPC
to obtain the lease time, which requires a sequence slot.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

We should not assume that nfs41_init_clientid() will always want to
initialise the session. If it is being called due to a server reboot, then
we just want to reset the session after re-establishing the clientid.

Fix this by getting rid of the 'reset' parameter in
nfs4_proc_create_session(), and instead relying on whether or not the
session slot table pointer is non-NULL.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

This patch invokes RECLAIM_COMPLETE after the client is done
reclaiming state.

There are interpretations of the spec that suggest that
RECLAIM_COMPLETE should also be issued after a new clientid
has been obtained from the server and even if there is no
state to reclaim.  This tells the server that the client
has no state to reclaim even if the client isn't aware the
server may have rebooted.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Implements RECLAIM_COMPLETE as an asynchronous RPC.
NFS4ERR_DELAY is retried, NFS4ERR_DEADSESSION invokes the error handling
but does not result in a retry, since we don't want to have a lingering
RECLAIM_COMPLETE call sent in the middle of a possible new state recovery
cycle.  If a session reset occurs, a new wave of reclaim operations will
follow, containing their own RECLAIM_COMPLETE call.  We don't want a
retry to get on the way of recovery by incorrectly indicating to the
server that we're done reclaiming state.

A subsequent patch invokes the functionality.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Otherwise we have no guarantees that other processes won't start another
RPC call while we're resetting the session.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

the server can indicate a number of error conditions by setting the
appropriate bits in the SEQUENCE operation. The client re-establishes
state with the server when it receives one of those, with the action
depending on the specific case.
Signed-off-by: NAlexandros Batsakis <batsakis@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Replace sync and async handlers setting of the NFS4CLNT_SESSION_SETUP bit with
setting NFS4CLNT_CHECK_LEASE, and let the state manager decide to reset the session.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the session is reset during state recovery, the state manager thread can
sleep on the slot_tbl_waitq causing a deadlock.

Add a completion framework to the session.  Have the state manager thread set
a new session state (NFS4CLNT_SESSION_DRAINING) and wait for the session slot
table to drain.

Signal the state manager thread in nfs41_sequence_free_slot when the
NFS4CLNT_SESSION_DRAINING bit is set and the session is drained.
Reported-by: NTrond Myklebust <trond@netapp.com>
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Do not fall through and set NFS4CLNT_SESSION_RESET bit on NFS4ERR_EXPIRED
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The bit is no longer used for session setup, only for session reset.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Reported-by: NTrond Myklebust <trond.myklebust@netapp.com>

Resetting the clientid from the state manager could result in not confirming
the clientid due to create session not being called.

Move the create session call from the NFS4CLNT_SESSION_SETUP state manager
initialize session case into the NFS4CLNT_LEASE_EXPIRED case establish_clid
call.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

The nfs4_state_manager should not be looking at the error values when
deciding whether or not to loop round in order to handle a higher priority
state recovery task. It should rather be looking at the clp->cl_state.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

nfs4_recovery_handle_error() will correctly handle errors such as
NFS4ERR_CB_PATH_DOWN, however because they are still passed back to the
main loop in nfs4_state_manager(), they can cause the latter to exit
prematurely.

Fix this by letting nfs4_recovery_handle_error() change the error value in
cases where there is no action required by the caller.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In practice, we need to ensure that we call nfs4_state_end_reclaim_reboot
in 2 cases:

 - If we lose the lease while we were reclaiming state
OR
 - After we're done with reboot recovery
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 76db6d95 (nfs41: add session setup
to the state manager) introduces an infinite loop possibility in the NFSv4
state manager. By first checking nfs4_has_session() before clearing the
NFS4CLNT_SESSION_SETUP flag, it allows for a situation where someone sets
that flag, but it never gets cleared, and so the state manager loops.

In fact commit c3fad1b1 (nfs41: add session
reset to state manager) causes this to happen every time we get a network
partition error.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>