setup_callback_client(), nfsd4_release_cb() and nfsd4_process_cb_update()
do not have users outside the translation unit. Let's declare it as
static.
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Already accepted by Bruce
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NFred Isaman <iisaman@netapp.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

In the sessions backchannel case, we don't need a krb5 principal name
for the client; we use the already-created forechannel credentials
instead.

Some cleanup, while we're there: make it clearer which code here is 4.0-
or sessions- specific.
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>

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>

Now that we have both nfsd4_callback and nfsd4_cb_conn structures, I get
confused if variables of both types are always named cb....
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Use NFS4_STATEID_SIZE from include/linux/nfs4
Signed-off-by: NAndy Adamson <andros@netapp.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

If a callback is retried at nfsd4_cb_recall_done() due to
some error, the returned rpc reply crashes here:

@@ -514,6 +514,7 @@ decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
 	u32 dummy;
 	__be32 *p;

 +	BUG_ON(!res);
 	if (res->cbs_minorversion == 0)
 		return 0;

[BUG_ON added for demonstration]

This is because the nfsd4_cb_done_sequence() has NULLed out
the task->tk_msg.rpc_resp pointer.

Also eventually the rpc would use the new slot without making
sure it is free by calling nfsd41_cb_setup_sequence().

This problem was introduced by a 4.1 protocol addition patch:
	[0421b5c5] nfsd41: Backchannel: Implement cb_recall over NFSv4.1

Which was overlooking the possibility of an RPC callback retries.
For not-4.1 case redoing the _prepare is harmless.
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

When the rarely-used callback-connection-changing setclientid occurs
simultaneously with a delegation recall, we rerun the recall by
requeueing it on a workqueue.  But we also need to take a reference on
the delegation in that case, since the delegation held by the rpc itself
will be released by the rpc_release callback.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

To be used also for the pnfs cb_layoutrecall callback
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
[nfsd4: fix cb_recall encoding]
    "nfsd: nfs4callback encode_stateid helper function" forgot to reserve
    more space after return from the new helper.
Reported-by: NMichael Groshans <groshans@citi.umich.edu>
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

We don't use this, and probably never will.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

If a recall fails for some unexpected reason, instead of ignoring it and
treating it like a success, it's safer to treat it as a failure,
preventing further delgation grants and returning CB_PATH_DOWN.

Also put put switches in a (two me) more logical order, with normal case
first.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Since rpc_call_async() guarantees that the release method will be called
even on failure, this put is wrong.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Note the position in the version array doesn't have to match the actual
rpc version number--to me it seems clearer to maintain the distinction.

Also document choice of rpc callback version number, as discussed in
e.g. http://www.ietf.org/mail-archive/web/nfsv4/current/msg07985.html
and followups.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

nfsd4_set_callback_client must be called under the state lock to atomically
set or unset the callback client and shutting down the previous one.
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>

Any null probe rpc will be synchronously destroyed by the
rpc_shutdown_client() in expire_client(), so the rpc task cannot outlast
the nfs4 client.  Therefore there's no need for that task to hold a
reference on the client.
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>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Instead of accessing the lease time directly, some users call
nfs4_lease_time(), and some a macro, NFSD_LEASE_TIME, defined as
nfs4_lease_time().  Neither layer of indirection serves any purpose.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

There's no need to allocate this cred more than once.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The server's callback client should stop trying to connect to the
client's callback server as soon as it gets ECONNREFUSED.

The NFS server's callback client does not call rpc_ping(), but appears
to have it's own "ping" procedure, so it wasn't covered by commit
caabea8a.
Signed-off-by: NChuck Lever <chuck.lever@oracle.com>
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>

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>

Now that the headers are fixed and carry their own wait, all fs/nfsd/
source files can include a minimal set of headers. and still compile just
fine.

This patch should improve the compilation speed of the nfsd module.
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

This patch enables the use of the nfsv4.1 backchannel.
Signed-off-by: NAlexandros Batsakis <batsakis@netapp.com>
[initialize rpc_create_args.bc_xprt too]
Signed-off-by: NBenny Halevy <bhalevy@panasas.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>