There was logic in the send path that assumed that a page containing data
to send to the client has a KVA. This is not always the case and can result
in data corruption when page_address returns zero and we end up DMA mapping
zero.

This patch changes the bus mapping logic to avoid page_address() where
necessary and converts all calls from ib_dma_map_single to ib_dma_map_page
in order to keep the map/unmap calls symmetric.
Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Expire clients more promptly, at the expense of possibly running the
laundromat thread more frequently.

Though it's not the default, I'd like it to be feasible to run with a
lease time of just a few seconds, at which point a minimum 10 second
wait between laundromat runs seems a little much.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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

We limit the number of 'defer' requests to DFR_MAX.

The imposition of this limit is spread about a bit - sometime we don't
add new things to the list, sometimes we remove old things.

Also it is currently applied to requests which we are 'waiting' for
rather than 'deferring'.  This doesn't seem ideal as 'waiting'
requests are naturally limited by the number of threads.

So gather the DFR_MAX handling code to one place and only apply it to
requests that are actually being deferred.

This means that not all 'cache_deferred_req' structures go on the
'cache_defer_list, so we need to be careful when adding and removing
things.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The return value from cache_defer_req is somewhat confusing.
Various different error codes are returned, but the single caller is
only interested in success or failure.

In fact it can measure this success or failure itself by checking
CACHE_PENDING, which makes the point of the code more explicit.

So change cache_defer_req to return 'void' and test CACHE_PENDING
after it completes, to see if the request was actually deferred or
not.

Similarly setup_deferral and cache_wait_req don't need a return value,
so make them void and remove some code.

The call to cache_revisit_request (to guard against a race) is only
needed for the second call to setup_deferral, so move it out of
setup_deferral to after that second call.  With the first call the
race is handled differently (by explicitly calling
'wait_for_completion').
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Commit 78155ed7 "nfsd4: distinguish
expired from stale stateids" attempted to distinguish expired and stale
stateid's using time information that may not have been completely
reliable, so I reverted it.

That was throwing out the baby with the bathwater; we still do want to
return expired, but let's do that using the simpler approach of just
assuming any stateid is expired if it looks like it was given out by the
current server instance, but we can't find it any more.

This may help clients that are recovering from network partitions.
Reported-by: Bian Naimeng <biannm@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

As long as we're not implementing any session security, we should just
automatically add any new connections that come along to the list of
sessions associated with the session.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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

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

NFSv4.1 needs warning when a client tcp connection goes down, if that
connection is being used as a backchannel, so that it can warn the
client that it has lost the backchannel connection.
Signed-off-by: J. 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: J. Bruce Fields <bfields@citi.umich.edu>

Changes:
	- make sure session memory reservation is released on failure
	  path.
	- use min_t()/min() for more compact code in several places.
	- break alloc_init_session into smaller pieces.
	- miscellaneous other cleanup.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

This returns an nfs error, not -ERRNO.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Note we're allocating an array of nfsd4_slot *'s, not nfsd4_slot's.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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: J. 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: J. 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: J. 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: J. Bruce Fields <bfields@citi.umich.edu>

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

Unfortunately, spkm3 never got very far; while interoperability with one
other implementation was demonstrated at some point, problems were found
with the spec that were deemed not worth fixing.

The kernel code is useless on its own without nfs-utils patches which
were never merged into nfs-utils, and were only ever available from
citi.umich.edu.  They appear not to have been updated since 2005.

Therefore it seems safe to assume that this code has no users, and never
will.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

If we set up to wait for a cache item to be filled in, and then find
that it is no longer pending, it could be that some other thread is
in 'cache_revisit_request' and has moved our request to its 'pending' list.
So when our setup_deferral calls cache_revisit_request it will find nothing to
put on the pending list, and do nothing.

We then return from cache_wait_req, thus leaving the 'sleeper'
on-stack structure open to being corrupted by subsequent stack usage.

However that 'sleeper' could still be on the 'pending' list that the
other thread is looking at and so any corruption could cause it to behave badly.

To avoid this race we simply take the same path as if the
'wait_for_completion_interruptible_timeout' was interrupted and if the
sleeper is no longer on the list (which it won't be) we wait on the
completion - which will ensure that any other cache_revisit_request
will have let go of the sleeper.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The context is already known in all the sock_create callers.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The net is known from the xprt_create and this tagging will also
give un the context in the conntection workers where real sockets
are created.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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

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

After this the socket creation in it knows the context.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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

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

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

The existing code adjusted it based on the worst case scenario for the returned
bitmap and the best case scenario for the supported attrs attribute.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[bfields@redhat.com: removed likely/unlikely's]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

On Wed, 29 Sep 2010 14:02:38 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> After merging the final tree, today's linux-next build (powerpc
> ppc44x_defconfig) produced tis warning:
>
> WARNING: net/sunrpc/sunrpc.o(.init.text+0x110): Section mismatch in reference from the function init_sunrpc() to the function .exit.text:rpcauth_remove_module()
> The function __init init_sunrpc() references
> a function __exit rpcauth_remove_module().
> This is often seen when error handling in the init function
> uses functionality in the exit path.
> The fix is often to remove the __exit annotation of
> rpcauth_remove_module() so it may be used outside an exit section.
>
> Probably caused by commit 2f72c9b7
> ("sunrpc: The per-net skeleton").

This actually causes a build failure on a sparc32 defconfig build:

`rpcauth_remove_module' referenced in section `.init.text' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o

I applied the following patch for today:

Fixes:

`rpcauth_remove_module' referenced in section `.init.text' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Everything that is required for that already exists:
* the per-net cache registration with respective proc entries
* the context (struct net) is available in all the users
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

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

Register empty per-net operations for the sunrpc layer.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

The transport representation should be per-net of course.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

Existing calls do the same, but for the init_net.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

There are two calls that operate on ip_map_cache and are
directly called from the nfsd code. Other places will be
handled in a different way.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>