Nobody calls nfs4_setup_sequence or nfs41_setup_sequence without
also calling rpc_call_start() on success. This commit therefore
folds the rpc_call_start call into nfs41_setup_sequence().
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

There is no point in using nfs4_setup_sequence or nfs4_sequence_done
in pure NFSv4.1 functions. We already know that those have sessions...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the server requests a lower target_highest_slotid, then ensure
that we ping it with at least one RPC call containing an
appropriate SEQUENCE op. This ensures that the server won't need to
send a recall callback in order to shrink the slot table.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

NFSv4.1 session management is getting complex enough to deserve
a separate file.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

nfs4_wait_clnt_recover and nfs4_client_recover_expired_lease are both
generic state related functions. As such, they belong in nfs4state.c,
and not nfs4proc.c
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Coalesce nfs4_check_drain_bc_complete and nfs4_check_drain_fc_complete
into a single function that can be called when the slot table is known
to be empty, then change nfs4_callback_free_slot() and nfs4_free_slot()
to use it.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the NFSv4.1 session slot allocation fails due to an ENOMEM condition,
then set the task->tk_timeout to 1/4 second to ensure that we do retry
the slot allocation more quickly.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

The state manager no longer needs any special machinery to stop the
session flow and resize the slot table. It is all done on the fly by
the SEQUENCE op code now.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Instead of an array of slots, use a singly linked list of slots that
can be dynamically appended to or shrunk.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Allow the server to control the size of the session slot table
by adjusting the value of sr_target_max_slots in the reply to the
SEQUENCE operation.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Ensure that the NFSv4.1 CB_RECALL_SLOT callback updates the slot table
target max slotid safely.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

When the server tells us that it is dynamically resizing the session
replay cache, we should reset the sequence number for those slots
that have been deallocated.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Dynamic slot allocation in NFSv4.1 depends on the client being able to
track the server's target value for the highest slotid in the
slot table.  See the reference in Section 2.10.6.1 of RFC5661.

To avoid ordering problems in the case where 2 SEQUENCE replies contain
conflicting updates to this target value, we also introduce a generation
counter, to track whether or not an RPC containing a SEQUENCE operation
was launched before or after the last update.

Also rename the nfs4_slot_table target_max_slots field to
'target_highest_slotid' to avoid confusion with a slot
table size or number of slots.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Change the argument to take the pointer to the slot, instead of
just the slotid.

We know that the new value of highest_used_slot must be less than
the current value. No need to scan the whole table.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Clean up the NFSv4.1 slot allocation by replacing nfs_find_slot() with
a function nfs_alloc_slot() that returns a pointer to the nfs4_slot
instead of an offset into the slot table.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Replace the session pointer + slotid with a pointer to the
allocated slot.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Instead of doing slot table pointer gymnastics every time we want to
know which slot we're using.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Move the session pointer into the slot table, then have struct nfs4_slot
point to that slot table.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Store the renewal time inside the session slot instead.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

All that memory is going to be initialised to non-zero by
nfs4_add_and_init_slots anyway.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We must always bump the clientid sequence number after a successful
call to CREATE_SESSION on the server. The result of
nfs4_verify_channel_attrs() is irrelevant to that requirement.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If we're mounting a new filesystem, ensure that the session has negotiated
large enough request and reply sizes to match the wsize and rsize mount
arguments.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Don't store the target request and response sizes in the same
variables used to store the server's replies to those targets.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If I mount an NFS v4.1 server to a single client multiple times and then
run xfstests over each mountpoint I usually get the client into a state
where recovery deadlocks.  The server informs the client of a
cb_path_down sequence error, the client then does a
bind_connection_to_session and checks the status of the lease.

I found that bind_connection_to_session sets the NFS4_SESSION_DRAINING
flag on the client, but this flag is never unset before
nfs4_check_lease() reaches nfs4_proc_sequence().  This causes the client
to deadlock, halting all NFS activity to the server.  nfs4_proc_sequence()
is only called by the state manager, so I can change it to run in privileged
mode to bypass the NFS4_SESSION_DRAINING check and avoid the deadlock.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

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

An EAGAIN return value would be unexpected, but there is no reason to
BUG...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Return errno - not an NFS4ERR_. This worked because NFS4ERR_ACCESS == EACCES.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

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

Use nfs_sb_deactive_async instead of nfs_sb_deactive when in a workqueue
context.  This avoids a deadlock where rpc_shutdown_client loops forever
in a workqueue kworker context, trying to kill all RPC tasks associated with
the client, while one or more of these tasks have already been assigned to the
same kworker (and will never run rpc_exit_task).

This approach is needed because RPC tasks that have already been assigned
to a kworker by queue_work cannot be canceled, as explained in the comment
for workqueue.c:insert_wq_barrier.
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
[Trond: add module_get/put.]
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the state recovery machinery is triggered by the call to
nfs4_async_handle_error() then we can deadlock.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

If we do not release the sequence id in cases where we fail to get a
session slot, then we can deadlock if we hit a recovery scenario.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

Currently, we will schedule session recovery and then return to the
caller of nfs4_handle_exception.  This works for most cases, but causes
a hang on the following test case:

	Client				Server
	------				------
	Open file over NFS v4.1
	Write to file
					Expire client
	Try to lock file

The server will return NFS4ERR_BADSESSION, prompting the client to
schedule recovery.  However, the client will continue placing lock
attempts and the open recovery never seems to be scheduled.  The
simplest solution is to wait for session recovery to run before retrying
the lock.
Signed-off-by: NBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

nfs4_open_recover_helper zeros the nfs4_opendata result structures, removing
the result access_request information which leads to an XDR decode error.

Move the setting of the result access_request field to nfs4_init_opendata_res
which sets all the other required nfs4_opendata result fields and is shared
between the open and recover open paths.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

We currently make no distinction in attribute requests between normal OPENs
and OPEN with CLAIM_PREVIOUS.  This offers more possibility of failures in
the GETATTR response which foils OPEN reclaim attempts.

Reduce the requested attributes to the bare minimum needed to update the
reclaim open stateid and split nfs4_opendata_to_nfs4_state processing
accordingly.
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

...before it can check the validity of that file type.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
will return permission denied for all bits until close.

Fixes a regression due to commit 6168f62c (NFSv4: Add ACCESS operation to
OPEN compound)
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Don't check MAY_WRITE as a newly created file may not have write mode bits,
but POSIX allows the creating process to write regardless.
This is ok because NFSv4 OPEN ops handle write permissions correctly -
the ACCESS in the OPEN compound is to differentiate READ v EXEC permissions.

Fixes a regression due to commit 6168f62c (NFSv4: Add ACCESS operation to
OPEN compound)
Signed-off-by: NWeston Andros Adamson <dros@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

If the layoutget call returns a stateid error, we want to invalidate the
layout stateid, and/or recover the open stateid.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

After commit e38eb650 (NFS: set_pnfs_layoutdriver() from
nfs4_proc_fsinfo()), set_pnfs_layoutdriver() is called inside
nfs4_proc_fsinfo(), but pnfs_blksize is not set. It causes setting
blocklayoutdriver failure and pnfsblock mount failure.

Cc: stable <stable@vger.kernel.org> [since v3.5]
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>