There are several reasons why this is undesirable:

 1. It never happens during normal operation anyway
 2. If it does happen it causes performance to be very, very poor
 3. It isn't likely to solve the original problem (memory shortage
    on remote DLM node) it was supposed to solve
 4. It uses a bunch of arbitrary constants which are unlikely to be
    correct for any particular situation and for which the tuning seems
    to be a black art.
 5. In an N node cluster, only 1/N of the dropped locked will actually
    contribute to solving the problem on average.

So all in all we are better off without it. This also makes merging
the lock_dlm module into GFS2 a bit easier.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch merges the lock_nolock module into GFS2 itself. As well as removing
some of the overhead of the module, it also means that its now impossible to
build GFS2 without a lock module (which would be a pointless thing to do
anyway).

We also plan to merge lock_dlm into GFS2 in the future, but that is a more
tricky task, and will therefore be a separate patch.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: David Teigland <teigland@redhat.com>

This looks like a lot of change, but in fact its not. Mostly its
things moving from one file to another. The change is just that
instead of queuing lock completions and callbacks from the DLM
we now pass them directly to GFS2.

This gives us a net loss of two list heads per glock (a fair
saving in memory) plus a reduction in the latency of delivering
the messages to GFS2, plus we now have one thread fewer as well.
There was a bug where callbacks and completions could be delivered
in the wrong order due to this unnecessary queuing which is fixed
by this patch.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>

This patch implements a number of cleanups to the core of the
GFS2 glock code. As a result a lot of code is removed. It looks
like a really big change, but actually a large part of this patch
is either removing or moving existing code.

There are some new bits too though, such as the new run_queue()
function which is considerably streamlined. Highlights of this
patch include:

 o Fixes a cluster coherency bug during SH -> EX lock conversions
 o Removes the "glmutex" code in favour of a single bit lock
 o Removes the ->go_xmote_bh() for inodes since it was duplicating
   ->go_lock()
 o We now only use the ->lm_lock() function for both locks and
   unlocks (i.e. unlock is a lock with target mode LM_ST_UNLOCKED)
 o The fast path is considerably shortly, giving performance gains
   especially with lock_nolock
 o The glock_workqueue is now used for all the callbacks from the DLM
   which allows us to simplify the lock_dlm module (see following patch)
 o The way is now open to make further changes such as eliminating the two
   threads (gfs2_glockd and gfs2_scand) in favour of a more efficient
   scheme.

This patch has undergone extensive testing with various test suites
so it should be pretty stable by now.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Bob Peterson <rpeterso@redhat.com>

__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>

Move the code that handles cluster posix locks from gfs2 into the dlm
so that it can be used by both gfs2 and ocfs2.
Signed-off-by: NDavid Teigland <teigland@redhat.com>

There are several places where GFP_KERNEL allocations happen under a glock,
which will result in hangs if we're under memory pressure and go to re-enter the
fs in order to flush stuff out.  This patch changes the culprits to GFS_NOFS to
keep this problem from happening.  Thank you,
Signed-off-by: NJosef Bacik <jbacik@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

GFS2 wasn't invalidating its cache before it called into the lock manager
with a request that could potentially drop a lock.  This was leaving a
window where the lock could be actually be held by another node, but the
file's page cache would still appear valid, causing coherency problems.
This patch moves the cache invalidation to before the lock manager call
when dropping a lock. It also adds the option to the lock_dlm lock
manager to not use conversion mode deadlock avoidance, which, on a
conversion from shared to exclusive, could internally drop the lock, and
then reacquire in. GFS2 now asks lock_dlm to not do this.  Instead, GFS2
manually drops the lock and reacquires it.
Signed-off-by: NBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch adds a proper extern declaration for gdlm_ops in
fs/gfs2/locking/dlm/lock_dlm.h
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The fl_owner is that of lockd when posix locks arrive from nfs
clients, so it can't be used to distinguish between lock holders.
Use fl_pid as owner instead; it's the pid of the process on the
nfs client.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Print error with log_error() to be consistent with others.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NFabio M. Di Nitto <fabbione@ubuntu.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The patch is a fix to abort mount if the mount.gfs* and possible
umount.* are missing from /sbin.

While we do what we can to guarantee that they are installed properly in
userland (CVS HEAD), we want to make sure that mount still aborts properly.

The only sign of missing helpers is that lock_dlm will receive no mount options
at all. According to David the problem does not exist for lock_nolock as the
helpers are not required.

The patch has been tested for both gfs and gfs2 and it works as expected. The
lack of mount.gfs* will generate an error that is propagated to mount:

oot@node1:~# mount -t  gfs2 /dev/nbd2 /mnt/
mount: wrong fs type, bad option, bad superblock on /dev/nbd2,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

[ 3513.303346] GFS2: fsid=: Trying to join cluster "lock_dlm", "gutsy:gfs2"
[ 3513.304546] DLM/GFS2/GFS ERROR: (u)mount helpers are not installed properly!
[ 3513.306290] GFS2: fsid=: can't mount proto=lock_dlm, table=gutsy:gfs2, hostdata=

You might want to notice that it will also avoid mount to hang or fail silently
or with strange errors that will require the cluster to reboot/restart before
you can actually mount the filesystem again.
Signed-off-by: NFabio M. Di Nitto <fabbione@ubuntu.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Use wait_event_interruptible() in the lock_dlm thread instead
of an open coded equivalent, and include a kthread_should_stop()
check in the wait test so we don't miss a kthread_stop().
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

There is no need for kobject_unregister() anymore, thanks to Kay's
kobject cleanup changes, so replace all instances of it with
kobject_put().


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Stop using kobject_register, as this way we can control the sending of
the uevent properly, after everything is properly initialized.

Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

kernel_kset does not need to be a kset, but a much simpler kobject now
that we have kobj_attributes.

We also rename kernel_kset to kernel_kobj to catch all users of this
symbol with a build error instead of an easy-to-ignore build warning.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Dynamically create the kset instead of declaring it statically.  We also
rename kernel_subsys to kernel_kset to catch all users of this symbol
with a build error instead of an easy-to-ignore build warning.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Dynamically create the kset instead of declaring it statically.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We don't need a "default" ktype for a kset.  We should set this
explicitly every time for each kset.  This change is needed so that we
can make ksets dynamic, and cleans up one of the odd, undocumented
assumption that the kset/kobject/ktype model has.

This patch is based on a lot of help from Kay Sievers.

Nasty bug in the block code was found by Dave Young
<hidave.darkstar@gmail.com>

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

A kset should not have its name set directly, so dynamically set the
name at runtime.

This is needed to remove the static array in the kobject structure which
will be changed in a future patch.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The problem boiled down to a race between the gdlm_init_threads()
function initializing thread1 and its setting of blist = 1.
Essentially, "if (current == ls->thread1)" was checked by the thread
before the thread creator set ls->thread1.

Since thread1 is the only thread who is allowed to work on the
blocking queue, and since neither thread thought it was thread1, no one
was working on the queue.  So everything just sat.

This patch reuses the ls->async_lock spin_lock to fix the race,
and it fixes the problem.  I've done more than 2000 iterations of the
loop that was recreating the failure and it seems to work.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

--

this is more clear.
Signed-off-by: NDenis Cheng <crquan@gmail.com>
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch cleans up duplicate includes in
	fs/gfs2/
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

We weren't returning the correct result when GETLK found a conflict,
which is indicated by userspace passing back a 1.

Signed-off-by: Abhijith Das <adas redhat com>
Signed-off-by: David Teigland <teigland redhat com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Set the owner field in the plock info sent to userspace for GETLK.
Without this, gfs_controld won't correctly see when the GETLK from a
process matches one of the process's existing locks.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Add a new flag, DLM_LSFL_FS, to be used when a file system creates a lockspace.
This flag causes the dlm to use GFP_NOFS for allocations instead of GFP_KERNEL.
(This updated version of the patch uses gfp_t for ls_allocation.)
Signed-Off-By: NPatrick Caulfield <pcaulfie@redhat.com>
Signed-Off-By: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

This patch removes the completion (which is rather large) from struct
gdlm_lock in favour of using the wait_on_bit() functions. We don't need
to add any extra fields to the structure to do this, so we save 32 bytes
(on x86_64) per structure. This adds up to quite a lot when we may
potentially have millions of these lock structures,
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Acked-by: NDavid Teigland <teigland@redhat.com>

Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add NFS lock support to GFS2.
Signed-off-by: NMarc Eshel <eshel@almaden.ibm.com>
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Acked-by: NSteven Whitehouse <swhiteho@redhat.com>

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>

We need to work on cleaning up the relationship between kobjects, ksets and
ktypes.  The removal of 'struct subsystem' is the first step of this,
especially as it is not really needed at all.

Thanks to Kay for fixing the bugs in this patch.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This sets the drop_count to 0 by default which is a better default
for most people.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

We always want to see the details of the error returned to gfs, but
log_debug is often turned off, so use log_error (printk).
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

The following patch speeds up lock_dlm's locking by moving the sprintf
out from the lock acquisition path and into the lock creation path. This
reduces the amount of CPU time used in acquiring locks by a fair amount.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Acked-by: NDavid Teigland <teigland@redhat.com>

Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We want to be able to change or disable the default drop_count (number at
which the dlm asks gfs to limit the the number of locks it's holding).
Add it to the collection of sysfs tunables for an fs.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

Increase the number of locks at which point the dlm begins asking gfs to
reduce its lock usage.  The default value is largely arbitrary, but the
current value of 50,000 ends up limiting performance unnecessarily for too
many users.
Signed-off-by: NDavid Teigland <teigland@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

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

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

The Makefile had the wrong CONFIG_ variable in it so that in
case GFS2 was y and the lock modules were m, they were not
getting built properly.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>