Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For every lock request lockd creates a new file_lock object
in nlmsvc_setgrantargs() by copying the passed in file_lock with
locks_copy_lock(). A filesystem can attach it's own lock_operations
vector to the file_lock. It has to be cleaned up at the end of the
file_lock's life. However, lockd doesn't do it today, yet it
asserts in nlmclnt_release_lockargs() that the per-filesystem
state is clean.
This patch fixes it by exporting locks_release_private() and adding
it to nlmsvc_freegrantargs(), to be symmetrical to creating a
file_lock in nlmsvc_setgrantargs().
Signed-off-by: NFelix Blyakher <felixb@sgi.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

No change in behavior, just rearranging the switch so that we break out
of the switch if and only if we're in the wait case.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

If a client requests a blocking lock, is denied, then requests it again,
then here in nlmsvc_lock() we will call vfs_lock_file() without FL_SLEEP
set, because we've already queued a block and don't need the locks code
to do it again.

But that means vfs_lock_file() will return -EAGAIN instead of
FILE_LOCK_DENIED.  So we still need to translate that -EAGAIN return
into a nlm_lck_blocked error in this case, and put ourselves back on
lockd's block list.

The bug was introduced by bde74e4b "locks: add special return
value for asynchronous locks".

Thanks to Frank van Maarseveen for the report; his original test
case was essentially

	for i in `seq 30`; do flock /nfsmount/foo sleep 10 & done
Tested-by: NFrank van Maarseveen <frankvm@frankvm.com>
Reported-by: NFrank van Maarseveen <frankvm@frankvm.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The current lockd does not reject reclaims that arrive outside of the
grace period.

Accepting a reclaim means promising to the client that no conflicting
locks were granted since last it held the lock.  We can meet that
promise if we assume the only lockers are nfs clients, and that they are
sufficiently well-behaved to reclaim only locks that they held before,
and that only reclaim locks have been permitted so far.  Once we leave
the grace period (and start permitting non-reclaims), we can no longer
keep that promise.  So we must start rejecting reclaims at that point.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Do all the grace period checks in svclock.c.  This simplifies the code a
bit, and will ease some later changes.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Use a special error value FILE_LOCK_DEFERRED to mean that a locking
operation returned asynchronously.  This is returned by

  posix_lock_file() for sleeping locks to mean that the lock has been
  queued on the block list, and will be woken up when it might become
  available and needs to be retried (either fl_lmops->fl_notify() is
  called or fl_wait is woken up).

  f_op->lock() to mean either the above, or that the filesystem will
  call back with fl_lmops->fl_grant() when the result of the locking
  operation is known.  The filesystem can do this for sleeping as well
  as non-sleeping locks.

This is to make sure, that return values of -EAGAIN and -EINPROGRESS by
filesystems are not mistaken to mean an asynchronous locking.

This also makes error handling in fs/locks.c and lockd/svclock.c slightly
cleaner.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: David Teigland <teigland@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Push it into those callback functions that actually need it.

Note that all the NFS operations use their own locking, so don't need the
BKL. Ditto for the rpcbind client.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

It may not be obvious (till you look at the definition of
nlm_alloc_call()) that a function like nlmsvc_create_block() should
consume a reference on success or failure, so I find it clearer if it
takes the reference it needs itself.

And both callers already do this immediately before the call anyway.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

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

nlmsvc_lock calls nlmsvc_lookup_host to find a nlm_host struct. The
callers of this function, however, call nlmsvc_retrieve_args or
nlm4svc_retrieve_args, which also return a nlm_host struct.

Change nlmsvc_lock to take a host arg instead of calling
nlmsvc_lookup_host itself and change the callers to pass a pointer to
the nlm_host they've already found.

Since nlmsvc_testlock() now just uses the caller's reference, we no
longer need to get or release it.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

nlmsvc_testlock calls nlmsvc_lookup_host to find a nlm_host struct. The
callers of this functions, however, call nlmsvc_retrieve_args or
nlm4svc_retrieve_args, which also return a nlm_host struct.

Change nlmsvc_testlock to take a host arg instead of calling
nlmsvc_lookup_host itself and change the callers to pass a pointer to
the nlm_host they've already found.

We take a reference to host in the place where nlmsvc_testlock()
previous did a new lookup, so the reference counting is unchanged from
before.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The file_lock structure is used both as a heavy-weight representation of
an active lock, with pointers to reference-counted structures, etc., and
as a simple container for parameters that describe a file lock.

The conflicting lock returned from __posix_lock_file is an example of
the latter; so don't call the filesystem or lock manager callbacks when
copying to it.  This also saves the need for an unnecessary
locks_init_lock in the nfsv4 server.

Thanks to Trond for pointing out the error.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>

As of 5996a298 ("NLM: don't unlock on
cancel requests") we no longer unlock in this case, so the comment is no
longer accurate.

Thanks to Stuart Friedberg for pointing out the inconsistency.

Cc: Stuart Friedberg <sfriedberg@hp.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Have lockd_up start lockd using kthread_run. With this change,
lockd_down now blocks until lockd actually exits, so there's no longer
need for the waitqueue code at the end of lockd_down. This also means
that only one lockd can be running at a time which simplifies the code
within lockd's main loop.

This also adds a check for kthread_should_stop in the main loop of
nlmsvc_retry_blocked and after that function returns. There's no sense
continuing to retry blocks if lockd is coming down anyway.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

It's possible for lockd to catch a SIGKILL while a GRANT_MSG callback
is in flight. If this happens we don't want lockd to insert the block
back into the nlm_blocked list.

This helps that situation, but there's still a possible race. Fixing
that will mean adding real locking for nlm_blocked.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

With the current scheme in nlmsvc_grant_blocked, we can end up with more
than one GRANT_MSG callback for a block in flight. Right now, we requeue
the block unconditionally so that a GRANT_MSG callback is done again in
30s. If the client is unresponsive, it can take more than 30s for the
call already in flight to time out.

There's no benefit to having more than one GRANT_MSG RPC queued up at a
time, so put it on the list with a timeout of NLM_NEVER before doing the
RPC call. If the RPC call submission fails, we requeue it with a short
timeout. If it works, then nlmsvc_grant_callback will end up requeueing
it with a shorter timeout after it completes.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Fix nlm_block leak for the case of supplied blocking lock info.
Signed-off-by: NOleg Drokin <green@linuxhacker.ru>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Without the patch, there is a leakage of nlmblock structure refcount
that holds a reference nlmfile structure, that holds a reference to
struct file, when async GETFL is used (-EINPROGRESS return from
file_ops->lock()), and also in some error cases.

Fix up a style nit while we're here.
Signed-off-by: NOleg Drokin <green@linuxhacker.ru>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The recent fix for a circular lock dependency unfortunately introduced a
potential memory leak in the event where the call to nlmsvc_lookup_host
fails for some reason.

Thanks to Roel Kluin for spotting this.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The problem is that the garbage collector for the 'host' structures
nlm_gc_hosts(), holds nlm_host_mutex while calling down to
nlmsvc_mark_resources, which, eventually takes the file->f_mutex.

We cannot therefore call nlmsvc_lookup_host() from within
nlmsvc_create_block, since the caller will already hold file->f_mutex, so
the attempt to grab nlm_host_mutex may deadlock.

Fix the problem by calling nlmsvc_lookup_host() outside the file->f_mutex.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rewrite nlmsvc_lock() to use the asynchronous interface.

As with testlock, we answer nlm requests in nlmsvc_lock by first looking up
the block and then using the results we find in the block if B_QUEUED is
set, and calling vfs_lock_file() otherwise.

If this a new lock request and we get -EINPROGRESS return on a non-blocking
request then we defer the request.

Also modify nlmsvc_unlock() to call the filesystem method if appropriate.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Normally we could skip ever having to allocate a block in the case where
the client asks for a non-blocking lock, or asks for a blocking lock that
succeeds immediately.

However we're going to want to always look up a block first in order to
check whether we're revisiting a deferred lock call, and to be prepared to
handle the case where the filesystem returns -EINPROGRESS--in that case we
want to make sure the lock we've given the filesystem is the one embedded
in the block that we'll use to track the deferred request.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Rewrite nlmsvc_testlock() to use the new asynchronous interface: instead of
immediately doing a posix_test_lock(), we first look for a matching block.
If the subsequent test_lock returns anything other than -EINPROGRESS, we
then remove the block we've found and return the results.

If it returns -EINPROGRESS, then we defer the lock request.

In the case where the block we find in the first step has B_QUEUED set,
we bypass the vfs_test_lock entirely, instead using the block to decide how
to respond:
	with nlm_lck_denied if B_TIMED_OUT is set.
	with nlm_granted if B_GOT_CALLBACK is set.
	by dropping if neither B_TIMED_OUT nor B_GOT_CALLBACK is set
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Change NLM internal interface to pass more information for test lock; we
need this to make sure the cookie information is pushed down to the place
where we do request deferral, which is handled for testlock by the
following patch.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

Add code to handle file system callback when the lock is finally granted.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

We need to keep some state for a pending asynchronous lock request, so this
patch adds that state to struct nlm_block.

This also adds a function which defers the request, by calling
rqstp->rq_chandle.defer and storing the resulting deferred request in a
nlm_block structure which we insert into lockd's global block list.  That
new function isn't called yet, so it's dead code until a later patch.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>

The nfsv4 protocol's lock operation, in the case of a conflict, returns
information about the conflicting lock.

It's unclear how clients can use this, so for now we're not going so far as to
add a filesystem method that can return a conflicting lock, but we may as well
return something in the local case when it's easy to.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu>

posix_test_lock() and ->lock() do the same job but have gratuitously
different interfaces.  Modify posix_test_lock() so the two agree,
simplifying some code in the process.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: N"J. Bruce Fields" <bfields@citi.umich.edu>

rpc_call_async() will always call rpc_release_calldata(), so it is an
error for __nlm_async_call() to do so as well.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

Annotated, all places switched to keeping status net-endian.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJosef Sipek <jsipek@fsl.cs.sunysb.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NTrond Myklebust <trond.myklebust@fys.uio.no>
Acked-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Both the (recently introduces) nsm_sema and the older f_sema are converted
over.

Cc: Olaf Kirch <okir@suse.de>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When we send a GRANTED_MSG call, we current copy the NLM cookie provided in
the original LOCK call - because in 1996, some broken clients seemed to rely
on this bug.  However, this means the cookies are not unique, so that when the
client's GRANTED_RES message comes back, we cannot simply match it based on
the cookie, but have to use the client's IP address in addition.  Which breaks
when you have a multi-homed NFS client.

The X/Open spec explicitly mentions that clients should not expect the same
cookie; so one may hope that any clients that were broken in 1996 have either
been fixed or rendered obsolete.
Signed-off-by: NOlaf Kirch <okir@suse.de>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch makes nlm_traverse{locks,blocks,shares} and friends use a function
pointer rather than a "action" enum.

This function pointer is given two nlm_hosts (one given by the caller, the
other taken from the lock/block/share currently visited), and is free to do
with them as it wants.  If it returns a non-zero value, the lockd/block/share
is released.
Signed-off-by: NOlaf Kirch <okir@suse.de>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch changes the nlm_blocked list to use a list_node instead of
homegrown linked list handling.
Signed-off-by: NOlaf Kirch <okir@suse.de>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds the peer's hostname (and name length) to all calls to
nlm*_lookup_host functions.  A subsequent patch will make use of these (is
requested by a sysctl).
Signed-off-by: NOlaf Kirch <okir@suse.de>
Signed-off-by: NNeil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>