Currently, the maximum number of connections that nfsd will allow
is based on the number of threads spawned. While this is fine for a
default, there really isn't a clear relationship between the two.

The number of threads corresponds to the number of concurrent requests
that we want to allow the server to process at any given time. The
connection limit corresponds to the maximum number of clients that we
want to allow the server to handle. These are two entirely different
quantities.

Break the dependency on increasing threads in order to allow for more
connections, by adding a new per-net parameter that can be set to a
non-zero value. The default is still to base it on the number of threads,
so there should be no behavior change for anyone who doesn't use it.

Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

PF_LESS_THROTTLE has a very specific use case: to avoid deadlocks
and live-locks while writing to the page cache in a loop-back
NFS mount situation.

It therefore makes sense to *only* set PF_LESS_THROTTLE in this
situation.
We now know when a request came from the local-host so it could be a
loop-back mount.  We already know when we are handling write requests,
and when we are doing anything else.

So combine those two to allow nfsd to still be throttled (like any
other process) in every situation except when it is known to be
problematic.
Signed-off-by: NNeilBrown <neilb@suse.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Without CONFIG_NFSD_V3, compile will get warning as,

fs/nfsd/nfssvc.c: In function 'nfsd_svc':
>> fs/nfsd/nfssvc.c:246:60: warning: array subscript is above array bounds [-Warray-bounds]
        return (nfsd_versions[2] != NULL) || (nfsd_versions[3] != NULL);
                                                               ^
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

When starting without nfsv2 and nfsv3, nfsd does not need to start
lockd (and certainly doesn't need to fail because lockd failed to
register with the portmapper).
Reported-by: NGareth Williams <gareth@garethwilliams.me.uk>
Reviewed-by: NChuck Lever <chuck.lever@oracle.com>
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

You can turn on or off support for minorversions using e.g.

	echo "-4.2" >/proc/fs/nfsd/versions

However, the current implementation is a little wonky.  For example, the
above will turn off 4.2 support, but it will also turn *on* 4.1 support.

This didn't matter as long as we only had 2 minorversions, which was
true till very recently.

And do a little cleanup here.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

We now have minimal minorversion 1 support; turn it on by default.

This can still be turned off with "echo -4.1 >/proc/fs/nfsd/versions".
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The three variables are calculated from nr_free_buffer_pages so change
their types to unsigned long in case of overflow.
Signed-off-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch makes NFSD file system superblock to be created per net.
This makes possible to get proper network namespace from superblock instead of
using hard-coded "init_net".

Note: NFSd fs super-block holds network namespace. This garantees, that
network namespace won't disappear from underneath of it.
This, obviously, means, that in case of kill of a container's "init" (which is not a mount
namespace, but network namespace creator) netowrk namespace won't be
destroyed.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The reply cache code never returns this status.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Since NFSd service is per-net now, we have to pass proper network
context in nfsd_shutdown() from NFSd kthreads.

The simplest way I found is to get proper net from one of transports
with permanent sockets.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Function nfsd_shutdown is called from two places: nfsd_last_thread (when last
kernel thread is exiting) and nfsd_svc (in case of kthreads starting error).
When calling from nfsd_svc(), we can be sure that per-net resources are
allocated, so we don't need to check per-net nfsd_net_up boolean flag.
This allows us to remove nfsd_shutdown function at all and move check for
per-net nfsd_net_up boolean flag to nfsd_last_thread.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Since we have generic NFSd resurces, we have to introduce some way how to
allocate and destroy those resources on first per-net NFSd start and on
last per-net NFSd stop respectively.
This patch replaces global boolean nfsd_up flag (which is unused now) by users
counter and use it to determine either we need to allocate generic resources
or destroy them.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This patch moves nfsd_startup_generic() and nfsd_shutdown_generic()
calls to nfsd_startup_net() and nfsd_shutdown_net() respectively, which
allows us to call nfsd_startup_net() instead of nfsd_startup() and makes
the code look clearer.  It also modifies nfsd_svc() and nfsd_shutdown()
to check nn->nfsd_net_up instead of global nfsd_up.  The latter is now
used only for generic resources shutdown and is currently useless.  It
will replaced by NFSd users counter later in this series.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

NFSd have per-net resources and resources, used globally.
Let's move generic resources init and shutdown to separated functions since
they are going to be allocated on first NFSd service start and destroyed after
last NFSd service shutdown.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This patch makes main step in NFSd containerisation.

There could be different approaches to how to make NFSd able to handle
incoming RPC request from different network namespaces.  The two main
options are:

1) Share NFSd kthreads betwween all network namespaces.
2) Create separated pool of threads for each namespace.

While first approach looks more flexible, second one is simpler and
non-racy.  This patch implements the second option.

To make it possible to allocate separate pools of threads, we have to
make it possible to allocate separate NFSd service structures per net.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This is simple: an NFSd service can be started at different times in
different network environments. So, its "boot time" has to be assigned
per net.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This patch introduces introduces per-net "nfsd_net_up" boolean flag, which has
the same purpose as general "nfsd_up" flag - skip init or shutdown of per-net
resources in case of they are inited on shutted down respectively.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

NFSd resources are partially per-net and partially globally used.
This patch splits resources init and shutdown and moves per-net code to
separated functions.
Generic and per-net init and shutdown are called sequentially for a while.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Precursor patch. Hard-coded "init_net" will be replaced by proper one in
future.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Precursor patch. Hard-coded "init_net" will be replaced by proper one in
future.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Precursor patch. Hard-coded "init_net" will be replaced by proper one in
future.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Precursor patch. Hard-coded "init_net" will be replaced by proper one in
future.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Precursor patch. Hard-coded "init_net" will be replaced by proper one in
future.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

There could be a situation, when NFSd was started in one network namespace, but
stopped in another one.
This will trigger kernel panic, because RPCBIND client is stored on per-net
NFSd data, and will be NULL on NFSd shutdown.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Split NFSv4 state init and shutdown into two different calls: per-net one and
generic one.
Per-net cwinit/shutdown pair have to be called for any namespace, generic pair
- only once on NSFd kthreads start and shutdown respectively.

Refresh of diff-nfsd-call-state-init-twice
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Very embarassing: 1091006c "nfsd: turn
on reply cache for NFSv4" missed a line, effectively leaving the reply
cache off in the v4 case.  I thought I'd tested that, but I guess not.

This time, wrote a pynfs test to confirm it works.

Cc: stable@vger.kernel.org
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

svc_recv() returns only -EINTR or -EAGAIN.  If we really want to worry
about the case where it has a bug that causes it to return something
else, we could stick a WARN() in svc_recv.  But it's silly to require
every caller to have all this boilerplate to handle that case.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

"port" in all these functions is always NFS_PORT.

nfsd can already be run on a nonstandard port using the "nfsd/portlist"
interface.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

In nfsd_destroy():

	if (destroy)
		svc_shutdown_net(nfsd_serv, net);
	svc_destroy(nfsd_server);

svc_shutdown_net(nfsd_serv, net) calls nfsd_last_thread(), which sets
nfsd_serv to NULL, causing a NULL dereference on the following line.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The idea is to separate service destruction and per-net operations,
because these are two different things and the mix looks ugly.

Notes:

1) For NFS server this patch looks ugly (sorry for that). But these
place will be rewritten soon during NFSd containerization.

2) LockD per-net counter increase int lockd_up() was moved prior to
make_socks() to make lockd_down_net() call safe in case of error.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This new routine is responsible for service registration in a specified
network context.

The idea is to separate service creation from per-net operations.

Note also: since registering service with svc_bind() can fail, the
service will be destroyed and during destruction it will try to
unregister itself from rpcbind. In this case unregistration has to be
skipped.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This patch also changes prototypes of nfsd_export_flush() and exp_rootfh():
network namespace parameter added.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

v2: dereference of most probably already released nlm_host removed in
nlmclnt_done() and reclaimer().

These routines are called from locks reclaimer() kernel thread. This thread
works in "init_net" network context and currently relays on persence on lockd
thread and it's per-net resources. Thus lockd_up() and lockd_down() can't relay
on current network context. So let's pass corrent one into them.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The rpc buffers will be allocated out of low memory, so we should really
only be taking that into account.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Move calculation of the default into a helper function.

Get rid of an unused variable "err" while we're there.

Thanks to Mi Jinlong for catching an arithmetic error in a previous
version.

Cc: Mi Jinlong <mijinlong@cn.fujitsu.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

On service shutdown we can be sure, that no more users of it left except
current. Thus it looks like using current network namespace context is safe in
this case.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Some files were using the complete module.h infrastructure without
actually including the header at all.  Fix them up in advance so
once the implicit presence is removed, we won't get failures like this:

  CC [M]  fs/nfsd/nfssvc.o
fs/nfsd/nfssvc.c: In function 'nfsd_create_serv':
fs/nfsd/nfssvc.c:335: error: 'THIS_MODULE' undeclared (first use in this function)
fs/nfsd/nfssvc.c:335: error: (Each undeclared identifier is reported only once
fs/nfsd/nfssvc.c:335: error: for each function it appears in.)
fs/nfsd/nfssvc.c: In function 'nfsd':
fs/nfsd/nfssvc.c:555: error: implicit declaration of function 'module_put_and_exit'
make[3]: *** [fs/nfsd/nfssvc.o] Error 1
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

We have to call svc_rpcb_cleanup() explicitly from nfsd_last_thread() since
this function is registered as service shutdown callback and thus nobody else
will done it for us.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>