ocfs2/cluster: Create debugfs files for live, quorum and failed region bitmaps

This patch prints the bitmaps of live, quorum and failed regions. This
information will be useful in debugging cluster issues.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Maintain bitmap of failed regions

In global heartbeat mode, we track the bitmap of regions that have seen
heartbeat timeouts. We fence if the number of such regions is greater than
or equal to half the number of quorum regions.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Maintain bitmap of quorum regions

o2hb allows online adding of regions. However, a newly added region is not
used in quorum calculations unless it has been added on all nodes. This patch
tracks a bitmap of such quorum regions.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Track bitmap of live heartbeat regions

A heartbeat region becomes live (or active) after a fixed number of (steady)
iterations.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Track number of global heartbeat regions

In global heartbeat mode, we have a upper limit for the number of active regions.
This patch adds the facility to track the number of active global heartbeat
regions and fails to start heartbeat if the number exceeds the maximum.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Maintain live node bitmap per heartbeat region

Currently we track a global livenode bitmap that keeps track of all nodes
that are heartbeating in all regions.

This patch adds the ability to track the livenode bitmap on a per region basis.
We will use this facility in a later patch to allow us to withstand the loss of
a minority number of regions.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Reorganize o2hb debugfs init

o2hb debugfs handling is reorganized to allow for easy expansion.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Check slots for unconfigured live nodes

o2hb currently checks slots for configured nodes only. This patch makes
it check the slots for the live nodes too to take care of a race in which
a node is removed from the configuration but not from the live map.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

Prints messages when the user adds or removes nodes.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Print messages when adding/removing heartbeat regions

Prints messages when the user adds or removes heartbeat regions in global
heartbeat mode. These messages are useful when debugging cluster related issues.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/dlm: Add message DLM_QUERY_NODEINFO

Adds new dlm message DLM_QUERY_NODEINFO that sends the attributes of all
registered nodes. This message is sent if the negotiated dlm protocol is
1.1 or higher. If the information of the joining node does not match
that of any existing nodes, the join domain request is rejected.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2: Print message if user mounts without starting global heartbeat

In global heartbeat mode, the heartbeat is started by the user. This patch
prints an error if the user attempts to mount a volume without starting the
heartbeat.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/dlm: Add message DLM_QUERY_REGION

Adds new dlm message DLM_QUERY_REGION that sends the names of all active
heartbeat regions. This message is only sent in the global heartbeat
mode. If the regions in the joining node do not fully match the ones in
the active nodes, the join domain request is rejected.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Get all heartbeat regions

Export function in o2hb to get a list of heartbeat regions. It also adds an
upper limit to the length of the heartbeat region name.

o2hb_global_heartbeat_active() currently disables global heartbeat. It will
be enabled in a later patch after all the code is added.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/dlm: Expose dlm_protocol in dlm_state

Add dlm_protocol to the list of info shown by the debugfs file, dlm_state.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2: Add support for heartbeat=global mount option

Adds support for heartbeat=global mount option. It ensures that the heartbeat
mode passed matches the one enabled on disk.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2: Add an incompat feature flag OCFS2_FEATURE_INCOMPAT_CLUSTERINFO

OCFS2_FEATURE_INCOMPAT_CLUSTERINFO allows us to use sb->s_cluster_info for
both userspace and o2cb cluster stacks. It also allows us to extend cluster
info to include stack flags.

This patch also adds stackflags to sb->s_clusterinfo. It also introduces a
clusterinfo flag OCFS2_CLUSTER_O2CB_GLOBAL_HEARTBEAT to denote the enabled
global heartbeat mode.

This incompat flag can be set/cleared using tunefs.ocfs2 --fs-features. The
clusterinfo flag is set/cleared using tunefs.ocfs2 --update-cluster-stack.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

ocfs2/cluster: Add heartbeat mode configfs parameter

Add heartbeat mode parameter to the configfs tree. This will be used
to set/show the heartbeat mode. The user is free to toggle the mode
between local and global as long as there is no active heartbeat region.
Signed-off-by: NSunil Mushran <sunil.mushran@oracle.com>

* 'upstream' of git://git.linux-mips.org/pub/scm/upstream-linus:
  MIPS: Octeon: Place cnmips_cu2_setup in __init memory.
  MIPS: Don't place cu2 notifiers in __cpuinitdata
  MIPS: Calculate VMLINUZ_LOAD_ADDRESS based on the length of vmlinux.bin
  MIPS: Alchemy: Resolve prom section mismatches
  MIPS: Fix syscall 64 bit number comments.
  MIPS: Hookup fanotify_init, fanotify_mark, and prlimit64 syscalls.
  MIPS: TX49xx: Rename ARCH_KMALLOC_MINALIGN to ARCH_DMA_MINALIGN
  MIPS: N32: Fix getdents64 syscall for n32
  MIPS: Remove pr_<level> uses of KERN_<level>
  MIPS: PNX8550: Sort out machine halt, restart and powerdown functions.
  MIPS: GIC: Remove dependencies from Malta files.
  MIPS: Kconfig: Fix and clarify kconfig help text for VSMP and SMTC.
  MIPS: DMA: Fix computation of DMA flags from device's coherent_dma_mask.
  MIPS: Audit: Fix hang in entry.S.
  MIPS: Document why RELOC_HIDE is there.
  MIPS: Octeon: Determine if helper needs to be built
  MIPS: Use generic atomic64 for 32-bit kernels
  MIPS: RM7000: Symbol should be static
  MIPS: kspd: Adjust confusing if indentation
  MIPS: Fix a typo.

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  writeback: always use sb->s_bdi for writeback purposes

* 'v2.6.36-rc6-urgent-fixes' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
  xen: do not initialize PV timers on HVM if !xen_have_vector_callback
  xen: do not set xenstored_ready before xenbus_probe on hvm

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: Initialize total_len in fuse_retrieve()

Since powerpc uses -Werror on arch powerpc, the build was broken like
this:

  cc1: warnings being treated as errors
  arch/powerpc/kernel/module.c: In function 'module_finalize':
  arch/powerpc/kernel/module.c:66: error: unused variable 'err'
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: rcu_read_lock_bh_held(): disabling irqs also disables bh
  generic-ipi: Fix deadlock in __smp_call_function_single

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf trace scripting: Fix extern struct definitions
  perf ui hist browser: Fix segfault on 'a' for annotate
  perf tools: Fix build breakage
  perf, x86: Handle in flight NMIs on P4 platform
  oprofile, ARM: Release resources on failure
  oprofile: Add Support for Intel CPU Family 6 / Model 29

The "flags" member of "struct wait_queue_t" is used in several places in
the kernel code without beeing initialized by init_wait().  "flags" is
used in bitwise operations.

If "flags" not initialized then unexpected behaviour may take place.
Incorrect flags might used later in code.

Added initialization of "wait_queue_t.flags" with zero value into
"init_wait".
Signed-off-by: NEvgeny Kuznetsov <EXT-Eugeny.Kuznetsov@nokia.com>
[ The bit we care about does end up being initialized by both
   prepare_to_wait() and add_to_wait_queue(), so this doesn't seem to
   cause actual bugs, but is definitely the right thing to do -Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With all the recent module loading cleanups, we've minimized the code
that sits under module_mutex, fixing various deadlocks and making it
possible to do most of the module loading in parallel.

However, that whole conversion totally missed the rather obscure code
that adds a new module to the list for BUG() handling.  That code was
doubly obscure because (a) the code itself lives in lib/bugs.c (for
dubious reasons) and (b) it gets called from the architecture-specific
"module_finalize()" rather than from generic code.

Calling it from arch-specific code makes no sense what-so-ever to begin
with, and is now actively wrong since that code isn't protected by the
module loading lock any more.

So this commit moves the "module_bug_{finalize,cleanup}()" calls away
from the arch-specific code, and into the generic code - and in the
process protects it with the module_mutex so that the list operations
are now safe.

Future fixups:
 - move the module list handling code into kernel/module.c where it
   belongs.
 - get rid of 'module_bug_list' and just use the regular list of modules
   (called 'modules' - imagine that) that we already create and maintain
   for other reasons.
Reported-and-tested-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Adrian Bunk <bunk@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

if !xen_have_vector_callback do not initialize PV timer unconditionally
because we still don't know how many cpus are available and if there is
more than one we won't be able to receive the timer interrupts on
cpu > 0.

This patch fixes an hang at boot when Xen does not support vector
callbacks and the guest has multiple vcpus.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>

Register_xenstore_notifier should guarantee that the caller gets
notified even if xenstore is already up.
Therefore we revert "do not notify callers from
register_xenstore_notifier" and set xenstored_read at the right time for
PV on HVM guests too.
In fact in case of PV on HVM guests xenstored is ready only after the
platform pci driver has completed the initialization, so do not set
xenstored_ready before the call to xenbus_probe().

This patch fixes a shutdown_event watcher registration bug that causes
"xm shutdown" not to work properly.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6:
  regulator: max8649 - fix setting extclk_freq
  regulator: fix typo in current units
  regulator: fix device_register() error handling

* 'merge-powerpc' of git://git.secretlab.ca/git/linux-2.6:
  powerpc/5200: tighten up ac97 reset timing
  powerpc/5200: efika.c: Add of_node_put to avoid memory leak
  powerpc/512x: fix clk_get() return value

* 'fix/misc' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: i2c/other/ak4xx-adda: Fix a compile warning with CONFIG_PROCFS=n
  ALSA: prevent heap corruption in snd_ctl_new()

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon: f71882fg: use a muxed resource lock for the Super I/O port

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] Fix memory leaks in pcc_cpufreq_do_osc
  [CPUFREQ] acpi-cpufreq: add missing __percpu markup

* 'merge-spi' of git://git.secretlab.ca/git/linux-2.6:
  of/spi: Fix OF-style driver binding of spi devices
  spi: spi-gpio.c tests SPI_MASTER_NO_RX bit twice, but not SPI_MASTER_NO_TX
  spi/mpc8xxx: fix buffer overrun on large transfers

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  vlan: dont drop packets from unknown vlans in promiscuous mode
  Phonet: Correct header retrieval after pskb_may_pull
  um: Proper Fix for f25c80a4: remove duplicate structure field initialization
  ip_gre: Fix dependencies wrt. ipv6.
  net-2.6: SYN retransmits: Add new parameter to retransmits_timed_out()
  iwl3945: queue the right work if the scan needs to be aborted
  mac80211: fix use-after-free

* 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel:
  drm/i915: Rephrase pwrite bounds checking to avoid any potential overflow
  drm/i915: Sanity check pread/pwrite
  drm/i915: Use pipe state to tell when pipe is off
  drm/i915: vblank status not valid while training display port
  drivers/gpu/drm/i915/i915_gem.c: Add missing error handling code
  drm/i915: Fix refleak during eviction.
  drm/i915: fix GMCH power reporting

Building under memory pressure, with KSM on 2.6.36-rc5, collapsed with
an internal compiler error: typically indicating an error in swapping.

Perhaps there's a timing issue which makes it now more likely, perhaps
it's just a long time since I tried for so long: this bug goes back to
KSM swapping in 2.6.33.

Notice how reuse_swap_page() allows an exclusive page to be reused, but
only does SetPageDirty if it can delete it from swap cache right then -
if it's currently under Writeback, it has to be left in cache and we
don't SetPageDirty, but the page can be reused.  Fine, the dirty bit
will get set in the pte; but notice how zap_pte_range() does not bother
to transfer pte_dirty to page_dirty when unmapping a PageAnon.

If KSM chooses to share such a page, it will look like a clean copy of
swapcache, and not be written out to swap when its memory is needed;
then stale data read back from swap when it's needed again.

We could fix this in reuse_swap_page() (or even refuse to reuse a
page under writeback), but it's more honest to fix my oversight in
KSM's write_protect_page().  Several days of testing on three machines
confirms that this fixes the issue they showed.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

2.6.36-rc1 commit 21d0d443 "rmap:
resurrect page_address_in_vma anon_vma check" was right to resurrect
that check; but now that it's comparing anon_vma->roots instead of
just anon_vmas, there's a danger of oopsing on a NULL anon_vma.

In most cases no NULL anon_vma ever gets here; but it turns out that
occasionally KSM, when enabled on a forked or forking process, will
itself call page_address_in_vma() on a "half-KSM" page left over from
an earlier failed attempt to merge - whose page_anon_vma() is NULL.

It's my bug that those should be getting here at all: I thought they
were already dealt with, this oops proves me wrong, I'll fix it in
the next release - such pages are effectively pinned until their
process exits, since rmap cannot find their ptes (though swapoff can).

For now just work around it by making page_address_in_vma() safe (and
add a comment on why that check is wanted anyway).  A similar check
in __page_check_anon_rmap() is safe because do_page_add_anon_rmap()
already excluded KSM pages.
Signed-off-by: NHugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>