If we lose the backchannel and then the client repairs the problem,
resend any callbacks.

We use a new cb_done flag to track whether there is still work to be
done for the callback or whether it can be destroyed with the rpc.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

If this loses any backchannel, make sure we have a chance to notice that
and set the sequence flags.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Distinguish between when the callback channel is known to be down, and
when it is not yet confirmed.  This will be useful in the 4.1 case.

Also, we don't seem to be using the fact that this field is atomic.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Basic xdr and processing for BIND_CONN_TO_SESSION.  This adds a
connection to the list of connections associated with a session.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

when callback is generated in NFSv4 server, it doesn't set the source
address. When an alias IP is utilized on NFSv4 server and suppose the
client is accessing via that alias IP (e.g. eth0:0), the client invokes
the callback to the IP address that is set on the original device (e.g.
eth0). This behavior results in timeout of xprt.
The patch sets the IP address that the client should invoke callback to.
Signed-off-by: NTakuma Umeya <tumeya@redhat.com>
[bfields@redhat.com: Simplify gen_callback arguments, use helper function]
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

When we converted to sharing struct filess between nfs4 opens I went too
far and also used the same mechanism for delegations.  But keeping
a reference to the struct file ensures it will outlast the lease, and
allows us to remove the lease with the same file as we added it.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The minorversion seems more a property of the client than the callback
channel.

Some time we should probably also enforce consistent minorversion usage
from the client; for now, this is just a cosmetic change.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Only one of the nfsd4_callback_probe callers actually cares about
changing the callback information.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The callback program is allowed to depend on the session which the
callback is going over.

No change in behavior yet, while we still only do callbacks over a
single session for the lifetime of the client.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Currently we don't deal well with a client that has multiple sessions
associated with it (even simultaneously, or serially over the lifetime
of the client).

In particular, we don't attempt to keep the backchannel running after
the original session diseappears.

We will fix that soon.

Once we do that, we need the slot sequence number to be per-session;
otherwise, for example, we cannot correctly handle a case like this:

	- All session 1 connections are lost.
	- The client creates session 2.  We use it for the backchannel
	  (since it's the only working choice).
	- The client gives us a new connection to use with session 1.
	- The client destroys session 2.

At this point our only choice is to go back to using session 1.  When we
do so we must use the sequence number that is next for session 1.  We
therefore need to maintain multiple sequence number streams.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Instead of copying the sessionid, use the new cl_cb_session pointer,
which indicates which session we're using for the backchannel.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The backchannel should  be associated with a session, it isn't really
global to the client.

We do, however, want a pointer global to the client which tracks which
session we're currently using for client-based callbacks.

This is a first step in that direction; for now, just reshuffling of
code with no significant change in behavior.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Remove connections from the list when they go down.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The spec requires us in various places to keep track of the connections
associated with each session.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Instead of creating the new rpc client from a regular server thread,
set a flag, kick off a null call, and allow the null call to do the work
of setting up the client on the callback workqueue.

Use a spinlock to ensure the callback work gets a consistent view of the
callback parameters.

This allows, for example, changing the callback from contexts where
sleeping is not allowed.  I hope it will also keep the locking simple as
we add more session and trunking features, by serializing most of the
callback-specific work.

This also closes a small race where the the new cb_ident could be used
with an old connection (or vice-versa).
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

I don't see the point of the separate struct.  It seems to just be
getting in the way.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

This will eventually allow us, for example, to kick off null callback
from contexts where we can't sleep.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Make the recall callback code more generic, so that other callbacks
will be able to use it too.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

With apologies for the gratuitous rename, the new name seems more
helpful to me.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

These two structs don't really need to be distinct as far as I can tell.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

If we already had a RW open for a file, and get a readonly open, we were
piggybacking on the existing RW open.  That's inconsistent with the
downgrade logic which blows away the RW open assuming you'll still have
a readonly open.

Also, make sure there is a readonly or writeonly open available for
locking, again to prevent bad behavior in downgrade cases when any RW
open may be lost.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The vfs doesn't really allow us to "upgrade" a file descriptor from
read-only to read-write, and our attempt to do so in nfs4_upgrade_open
is ugly and incomplete.

Move to a different scheme where we keep multiple opens, shared between
open stateid's, in the nfs4_file struct.  Each file will be opened at
most 3 times (for read, write, and read-write), and those opens will be
shared between all clients and openers.  On upgrade we will do another
open if necessary instead of attempting to upgrade an existing open.
We keep count of the number of readers and writers so we know when to
close the shared files.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Get a refcount on the client on SEQUENCE,
Release the refcount and renew the client when all respective compounds completed.
Do not expire the client by the laundromat while in use.
If the client was expired via another path, free it when the compounds
complete and the refcount reaches 0.

Note that unhash_client_locked must call list_del_init on cl_lru as
it may be called twice for the same client (once from nfs4_laundromat
and then from expire_client)
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Mark the client as expired under the client_lock so it won't be renewed
when an nfsv4.1 session is done, after it was explicitly expired
during processing of the compound.

Do not renew a client mark as expired (in particular, it is not
on the lru list anymore)
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Currently just initialize the cl_refcount to 1
and decrement in expire_client(), conditionally freeing the
client when the refcount reaches 0.

To be used later by nfsv4.1 compounds to keep the client from
timing out while in use.
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The rfc allows a client to change the callback parameters, but we didn't
previously implement it.

Teach the callbacks to rerun themselves (by placing themselves on a
workqueue) when they recognize that their rpc task has been killed and
that the callback connection has changed.

Then we can change the callback connection by setting up a new rpc
client, modifying the nfs4 client to point at it, waiting for any work
in progress to complete, and then shutting down the old client.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Mainly I just want to separate the arguments used for setting up the tcp
client from the rest.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Now that the shutdown sequence guarantees callbacks are shut down before
the client is destroyed, we no longer have a use for cl_count.

We'll probably reinstate a reference count on the client some day, but
it will be held by users other than callbacks.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The NFSv4 server's fl_break callback can sleep (dropping the BKL), in
order to allocate a new rpc task to send a recall to the client.

As far as I can tell this doesn't cause any races in the current code,
but the analysis is difficult.  Also, the sleep here may complicate the
move away from the BKL.

So, just schedule some work to do the job for us instead.  The work will
later also prove useful for restarting a call after the callback
information is changed.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Instead of allocating this small structure, just include it in the
delegation.

The nfsd4_callback structure isn't really necessary yet, but we plan to
add to it all the information necessary to perform a callback.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The new .h files have paths at the top that are now out of date.  While
we're here, just remove all of those from fs/nfsd; they never served any
purpose.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Most of this can be trivially moved to a private header as well.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Lots of include/linux/nfsd/* headers are only used by
nfsd module. Move them to the source directory
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

* Add includes that are directly used by headers
* Remove includes that are not needed

These are the changes made:

[xdr.h]
struct nfsd_readdirres has an embedded struct readdir_cd from nfsd.h
fixing that we can drop other includes

[xdr4.h]
embedded types defined both at state.h and nfsd.h

[syscall.h]
After export.h fix none of these stuff is needed.
fix extra space in # include <> statement

[stats.h]
does not need <linux/nfs4.h> but was export to user-mode
so I don't touch it

[state.h]
embedded types from nfsfh.h like struct knfsd_fh. bringing that
eliminates the need for all other includes

[nfsfh.h]
directly manipulating types from sunrpc/svc.h.
Removed Other unused headers.

[nfsd.h]
removed unused headers include

[export.h]
lots of sunrpc/svc.h types and a single prototype declaration
with pointer from nfsfh.h, but all users of export.h do need
nfsfh.h any way. remove now un-needed include.

[const.h]
Unfixed (not independent)

[cache.h]
could do with a forward declaration of "struct svc_rqst;"
from sunrpc/svc.h but all users absolutely will need
sunrpc/svc.h it is easier overall this way.
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Follows the model used by the NFS client.  Setup the RPC prepare and done
function pointers so that we can populate the sequence information if
minorversion == 1.  rpc_run_task() is then invoked directly just like
existing NFS client operations do.

nfsd4_cb_prepare() determines if the sequence information needs to be setup.
If the slot is in use, it adds itself to the wait queue.

nfsd4_cb_done() wakes anyone sleeping on the callback channel wait queue
after our RPC reply has been received.  It also sets the task message
result pointer to NULL to clearly indicate we're done using it.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
[define and initialize cl_cb_seq_nr here]
[pulled out unused defintion of nfsd4_cb_done]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

RPC callback requests will wait on this wait queue if the backchannel
is out of slots.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Follow the model we use in the client. Make the sequence arguments
part of the regular RPC arguments.  None of the callbacks that are
soon to be implemented expect results that need to be passed back
to the caller, so we don't define a separate RPC results structure.
For session validation, the cb_sequence decoding will use a pointer
to the sequence arguments that are part of the RPC argument.
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
[define struct nfsd4_cb_sequence here]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Keep the xprt used for create_session in cl_cb_xprt.
Mark cl_callback.cb_minorversion = 1 and remember
the client provided cl_callback.cb_prog rpc program number.
Use it to probe the callback path.

Use the client's network address to initialize as the
callback's address as expected by the xprt creation
routines.

Define xdr sizes and code nfs4_cb_compound header to be able
to send a null callback rpc.

Signed-off-by: Andy Adamson<andros@netapp.com>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NRicardo Labiaga <Ricardo.Labiaga@netapp.com>
[get callback minorversion from fore channel's]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[nfsd41: change bc_sock to bc_xprt]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[pulled definition for cl_cb_xprt]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[nfsd41: set up backchannel's cb_addr]
[moved rpc_create_args init to "nfsd: modify nfsd4.1 backchannel to use new xprt class"]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>