hlist_for_each_entry binds its first argument to a non-null value, and thus
any null test on the value of that argument is superfluous.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
iterator I;
expression x,E,E1,E2;
statement S,S1,S2;
@@

I(x,...) { <...
- (x != NULL) &&
  E
  ...> }
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Commit 7fe2b319 fixed possible
misordering of completion asts (casts) and blocking asts (basts)
for kernel locks.  This patch does the same for locks taken by
user space applications.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Smatch complains because "lkb" is never NULL.  Looking at it, the original
code actually adds the new element to the end of the list fine, so we can
just get rid of the if condition.  This code is four years old and no one
has complained so it must work.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

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>

Constify struct sysfs_ops.

This is part of the ops structure constification
effort started by Arjan van de Ven et al.

Benefits of this constification:

 * prevents modification of data that is shared
   (referenced) by many other structure instances
   at runtime

 * detects/prevents accidental (but not intentional)
   modification attempts on archs that enforce
   read-only kernel data at runtime

 * potentially better optimized code as the compiler
   can assume that the const data cannot be changed

 * the compiler/linker move const data into .rodata
   and therefore exclude them from false sharing
Signed-off-by: NEmese Revfy <re.emese@gmail.com>
Acked-by: NDavid Teigland <teigland@redhat.com>
Acked-by: NMatt Domsch <Matt_Domsch@dell.com>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: NHans J. Koch <hjk@linutronix.de>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NJens Axboe <jens.axboe@oracle.com>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The bast mode that appears in the debugfs output should be
useful on both master and process nodes.  lkb_highbast is
currently printed, and is only useful on the master node.
lkb_bastmode is only useful on the process node.  This
patch sets lkb_bastmode on the master node as well, and
uses that value in the debugfs print.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Although it is possible to get this information from the path,
its much easier to provide the lockspace as a seperate env
variable.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

When the lock master processes a successful operation (request,
convert, cancel, or unlock), it will process the effects of the
change before sending the reply for the operation.  The "effects"
of the operation are:

- blocking callbacks (basts) for any newly granted locks
- waiting or converting locks that can now be granted

The cast is queued on the local node when the reply from the lock
master is received.  This means that a lock holder can receive a
bast for a lock mode that is doesn't yet know has been granted.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

When both blocking and completion callbacks are queued for lock,
the dlm would always deliver the completion callback (cast) first.
In some cases the blocking callback (bast) is queued before the
cast, though, and should be delivered first.  This patch keeps
track of the order in which they were queued and delivers them
in that order.

This patch also keeps track of the granted mode in the last cast
and eliminates the following bast if the bast mode is compatible
with the preceding cast mode.  This happens when a remotely mastered
lock is demoted, e.g. EX->NL, in which case the local node queues
a cast immediately after sending the demote message.  In this way
a cast can be queued for a mode, e.g. NL, that makes an in-transit
bast extraneous.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Some comments misspell "truly"; this fixes them. No code changes.
Signed-off-by: NAdam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Replace all GFP_KERNEL and ls_allocation with GFP_NOFS.
ls_allocation would be GFP_KERNEL for userland lockspaces
and GFP_NOFS for file system lockspaces.

It was discovered that any lockspaces on the system can
affect all others by triggering memory reclaim in the
file system which could in turn call back into the dlm
to acquire locks, deadlocking dlm threads that were
shared by all lockspaces, like dlm_recv.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The code to set up sctp sockets was not using the sockfd_lookup()
and sockfd_put() routines to translate an fd to a socket.  The
direct fget and fput calls were resulting in error messages from
alloc_fd().

Also clean up two log messages and remove a third, related to
setting up sctp associations.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The recently added dlm_lowcomms_connect_node() from
391fbdc5 does not work
when using SCTP instead of TCP.  The sctp connection code
has nothing to do without data to send.  Check for no data
in the sctp connection code and do nothing instead of
triggering a BUG.  Also have connect_node() do nothing
when the protocol is sctp.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Make all seq_operations structs const, to help mitigate against
revectoring user-triggerable function pointers.

This is derived from the grsecurity patch, although generated from scratch
because it's simpler than extracting the changes from there.
Signed-off-by: NJames Morris <jmorris@namei.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Using kernel_sendpage() is cleaner and safer than following
sock->ops ourselves.
Signed-off-by: NPaolo Bonzini <bonzini@gnu.org>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Closing a connection to a node can create problems if there are
outstanding messages for that node.  The problems include dlm_send
spinning attempting to reconnect, or BUG from tcp_connect_to_sock()
attempting to use a partially closed connection.

To cleanly close a connection, we now first attempt to send any pending
messages, cancel any remaining workqueue work, and flag the connection
as closed to avoid reconnect attempts.
Signed-off-by: NLars Marowsky-Bree <lmb@suse.de>
Signed-off-by: NChristine Caulfield <ccaulfie@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The last correction to the tcp_connect_to_sock error exit path,
commit a89d63a1, can free an already
freed socket, due to collision with a previous (incomplete) attempt
to fix the same issue, commit 311f6fc7.
Signed-off-by: NCasey Dahlin <cdahlin@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

In the tcp_connect_to_sock() error exit path, the socket
allocated at the top of the function was not being freed.
Signed-off-by: NCasey Dahlin <cdahlin@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

This makes generic netlink network namespace aware. No
generic netlink families except for the controller family
are made namespace aware, they need to be checked one by
one and then set the family->netnsok member to true.

A new function genlmsg_multicast_netns() is introduced to
allow sending a multicast message in a given namespace,
for example when it applies to an object that lives in
that namespace, a new function genlmsg_multicast_allns()
to send a message to all network namespaces (for objects
that do not have an associated netns).

The function genlmsg_multicast() is changed to multicast
the message in just init_net, which is currently correct
for all generic netlink families since they only work in
init_net right now. Some will later want to work in all
net namespaces because they do not care about the netns
at all -- those will have to be converted to use one of
the new functions genlmsg_multicast_allns() or
genlmsg_multicast_netns() whenever they are made netns
aware in some way.

After this patch families can easily decide whether or
not they should be available in all net namespaces. Many
genl families us it for objects not related to networking
and should therefore be available in all namespaces, but
that will have to be done on a per family basis.

Note that this doesn't touch on the checkpoint/restart
problem where network namespaces could be used, genl
families and multicast groups are numbered globally and
I see no easy way of changing that, especially since it
must be possible to multicast to all network namespaces
for those families that do not care about netns.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix a regression from the original addition of nfs lock support
586759f0.  When a synchronous
(non-nfs) plock completes, the waiting thread will wake up and
free the op struct.  This races with the user thread in
dev_write() which goes on to read the op's callback field to
check if the lock is async and needs a callback.  This check
can happen on the freed op.  The fix is to note the callback
value before the op can be freed.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

  CC [M]  fs/dlm/lock.o
fs/dlm/lock.c: In function ‘find_rsb’:
fs/dlm/lock.c:438: warning: ‘r’ may be used uninitialized in this function

Since r is used on the error path to set r_ret, set it to NULL.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Change some GFP_KERNEL allocations to use either GFP_NOFS or
ls_allocation (when available) which the fs sets to GFP_NOFS.
The point is to prevent allocations from going back into the
cluster fs in places where that might lead to deadlock.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Make network connections to other nodes earlier, in the context of
dlm_recoverd.  This avoids connecting to nodes from dlm_send where we
try to avoid allocations which could possibly deadlock if memory reclaim
goes into the cluster fs which may try to do a dlm operation.
Signed-off-by: NChristine Caulfield <ccaulfie@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

When a lockspace was joined multiple times, the global dlm
use count was incremented when it should not have been.  This
caused the global dlm threads to not be stopped when all
lockspaces were eventually be removed.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

| fs/gfs2/lock_dlm.c:207: warning: passing argument 1 of 'dlm_new_lockspace' discards qualifiers from pointer target type
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Using offsetof() to calculate name length does not work because
it does not produce consistent results with with structure packing.
This caused memcpy to corrupt memory by copying 4 extra bytes off
the end of the buffer on 64 bit kernels with 32 bit userspace
(the only case where this 32/64 compat code is used).

The fix is to calculate name length directly from the start instead
of trying to derive it later using count and offsetof.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Return immediately from dlm_unlock(CANCEL) if the lock is
granted and not being converted; there's nothing to cancel.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

When a conversion completes successfully and finds that a cancel
of the convert is still in progress (which is now a moot point),
preemptively clear the state associated with outstanding cancel.
That state could cause a subsequent conversion to be ignored.

Also, improve the consistency and content of error and debug
messages in this area.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Integer nodeids can be too large for the idr code; use a hash
table instead.
Signed-off-by: NChristine Caulfield <ccaulfie@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The ls_dirtbl[].lock was an rwlock, but since it was only used in write
mode a spinlock will suffice.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

dlm_posix_get fills out the relevant fields in the file_lock before
returning when there is a lock conflict, but doesn't clean out any of
the other fields in the file_lock.

When nfsd does a NFSv4 lockt call, it sets the fl_lmops to
nfsd_posix_mng_ops before calling the lower fs. When the lock comes back
after testing a lock on GFS2, it still has that field set. This confuses
nfsd into thinking that the file_lock is a nfsd4 lock.

Fix this by making DLM reinitialize the file_lock before copying the
fields from the conflicting lock.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

We should use the original copy of the file_lock, fl, instead
of the copy, flc in the lockd notify callback.  The range in flc has
been modified by posix_lock_file(), so it will not match a copy of the
lock in lockd.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The rwlock is almost always used in write mode, so there's no reason
to not use a spinlock instead.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The old code would leak iterators and leave reference counts on
rsbs because it was ignoring the "stop" seq callback.  The code
followed an example that used the seq operations differently.
This new code is based on actually understanding how the seq
operations work.  It also improves things by saving the hash bucket
in the position to avoid cycling through completed buckets in start.
Siged-off-by: NDavd Teigland <teigland@redhat.com>

fs/dlm/ast.c: In function 'dlm_astd':
fs/dlm/ast.c:64: warning: 'bastmode' may be used uninitialized in this function

Cleans code up.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid Teigland <teigland@redhat.com>

The new debugfs entry dumps all rsb and lkb structures, and includes
a lot more information than has been available before.  This includes
the new timestamps added by a previous patch for debugging callback
issues.
Signed-off-by: NDavid Teigland <teigland@redhat.com>