Merge branch 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, microcode, AMD: Fix signedness bug in generic_load_microcode()
  x86, microcode, AMD: Extend ucode size verification
  x86, microcode, AMD: Cleanup dmesg output
  x86, microcode, AMD: Remove unneeded memset call
  x86, microcode, AMD: Simplify get_next_ucode
  x86, microcode, AMD: Simplify install_equiv_cpu_table
  x86, microcode, AMD: Release firmware on error
  x86, microcode: Correct sysdev_add error path

* 'um-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  um: Select GENERIC_HARDIRQS_NO_DEPRECATED
  um: Use proper accessors in show_interrupts()
  um: Convert irq_chips to new functions
  um: Remove stale irq_chip.end

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

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (116 commits)
  x86: Enable forced interrupt threading support
  x86: Mark low level interrupts IRQF_NO_THREAD
  x86: Use generic show_interrupts
  x86: ioapic: Avoid redundant lookup of irq_cfg
  x86: ioapic: Use new move_irq functions
  x86: Use the proper accessors in fixup_irqs()
  x86: ioapic: Use irq_data->state
  x86: ioapic: Simplify irq chip and handler setup
  x86: Cleanup the genirq name space
  genirq: Add chip flag to force mask on suspend
  genirq: Add desc->irq_data accessor
  genirq: Add comments to Kconfig switches
  genirq: Fixup fasteoi handler for oneshot mode
  genirq: Provide forced interrupt threading
  sched: Switch wait_task_inactive to schedule_hrtimeout()
  genirq: Add IRQF_NO_THREAD
  genirq: Allow shared oneshot interrupts
  genirq: Prepare the handling of shared oneshot interrupts
  genirq: Make warning in handle_percpu_event useful
  x86: ioapic: Move trigger defines to io_apic.h
  ...

Fix up trivial(?) conflicts in arch/x86/pci/xen.c due to genirq name
space changes clashing with the Xen cleanups.  The set_irq_msi() had
moved to xen_bind_pirq_msi_to_irq().

Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Combine printk()s in show_regs_common()
  x86: Don't call dump_stack() from arch_trigger_all_cpu_backtrace_handler()

* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix and clean up generic_processor_info()
  x86: Don't copy per_cpu cpuinfo for BSP two times
  x86: Move llc_shared_map out of cpu_info

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, binutils, xen: Fix another wrong size directive
  x86: Remove dead config option X86_CPU
  x86: Really print supported CPUs if PROCESSOR_SELECT=y
  x86: Fix a bogus unwind annotation in lib/semaphore_32.S
  um, x86-64: Fix UML build after adding CFI annotations to lib/rwsem_64.S
  x86: Remove unused bits from lib/thunk_*.S
  x86: Use {push,pop}_cfi in more places
  x86-64: Add CFI annotations to lib/rwsem_64.S
  x86, asm: Cleanup unnecssary macros in asm-offsets.c
  x86, system.h: Drop unused __SAVE/__RESTORE macros
  x86: Use bitmap library functions
  x86: Partly unify asm-offsets_{32,64}.c
  x86: Reduce back the alignment of the per-CPU data section

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

* 'timers-rtc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  RTC: Fix up rtc.txt documentation to reflect changes to generic rtc layer
  RTC: sa1100: Update the sa1100 RTC driver.
  RTC: Fix the cross interrupt issue on rtc-test.
  RTC: Remove UIE and PIE information from the sa1100 driver proc.
  RTC: Include information about UIE and PIE in RTC driver proc.
  RTC: Clean out UIE icotl implementations
  RTC: Cleanup rtc_class_ops->update_irq_enable()
  RTC: Cleanup rtc_class_ops->irq_set_freq()
  RTC: Cleanup rtc_class_ops->irq_set_state
  RTC: Initialize kernel state from RTC

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

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (62 commits)
  posix-clocks: Check write permissions in posix syscalls
  hrtimer: Remove empty hrtimer_init_hres_timer()
  hrtimer: Update hrtimer->state documentation
  hrtimer: Update base[CLOCK_BOOTTIME].offset correctly
  timers: Export CLOCK_BOOTTIME via the posix timers interface
  timers: Add CLOCK_BOOTTIME hrtimer base
  time: Extend get_xtime_and_monotonic_offset() to also return sleep
  time: Introduce get_monotonic_boottime and ktime_get_boottime
  hrtimers: extend hrtimer base code to handle more then 2 clockids
  ntp: Remove redundant and incorrect parameter check
  mn10300: Switch do_timer() to xtimer_update()
  posix clocks: Introduce dynamic clocks
  posix-timers: Cleanup namespace
  posix-timers: Add support for fd based clocks
  x86: Add clock_adjtime for x86
  posix-timers: Introduce a syscall for clock tuning.
  time: Splitout compat timex accessors
  ntp: Add ADJ_SETOFFSET mode bit
  time: Introduce timekeeping_inject_offset
  posix-timer: Update comment
  ...

Fix up new system-call-related conflicts in
	arch/x86/ia32/ia32entry.S
	arch/x86/include/asm/unistd_32.h
	arch/x86/include/asm/unistd_64.h
	arch/x86/kernel/syscall_table_32.S
(name_to_handle_at()/open_by_handle_at() vs clock_adjtime()), and some
due to movement of get_jiffies_64() in:
	kernel/time.c

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

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (26 commits)
  sched: Resched proper CPU on yield_to()
  sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy
  sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks
  sched: Clean up the IRQ_TIME_ACCOUNTING code
  sched: Add #ifdef around irq time accounting functions
  sched, autogroup: Stop claiming ownership of the root task group
  sched, autogroup: Stop going ahead if autogroup is disabled
  sched, autogroup, sysctl: Use proc_dointvec_minmax() instead
  sched: Fix the group_imb logic
  sched: Clean up some f_b_g() comments
  sched: Clean up remnants of sd_idle
  sched: Wholesale removal of sd_idle logic
  sched: Add yield_to(task, preempt) functionality
  sched: Use a buddy to implement yield_task_fair()
  sched: Limit the scope of clear_buddies
  sched: Check the right ->nr_running in yield_task_fair()
  sched: Avoid expensive initial update_cfs_load(), on UP too
  sched: Fix switch_from_fair()
  sched: Simplify the idle scheduling class
  softirqs: Account ksoftirqd time as cpustat softirq
  ...

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

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (184 commits)
  perf probe: Clean up probe_point_lazy_walker() return value
  tracing: Fix irqoff selftest expanding max buffer
  tracing: Align 4 byte ints together in struct tracer
  tracing: Export trace_set_clr_event()
  tracing: Explain about unstable clock on resume with ring buffer warning
  ftrace/graph: Trace function entry before updating index
  ftrace: Add .ref.text as one of the safe areas to trace
  tracing: Adjust conditional expression latency formatting.
  tracing: Fix event alignment: skb:kfree_skb
  tracing: Fix event alignment: mce:mce_record
  tracing: Fix event alignment: kvm:kvm_hv_hypercall
  tracing: Fix event alignment: module:module_request
  tracing: Fix event alignment: ftrace:context_switch and ftrace:wakeup
  tracing: Remove lock_depth from event entry
  perf header: Stop using 'self'
  perf session: Use evlist/evsel for managing perf.data attributes
  perf top: Don't let events to eat up whole header line
  perf top: Fix events overflow in top command
  ring-buffer: Remove unused #include <linux/trace_irq.h>
  tracing: Add an 'overwrite' trace_option.
  ...

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

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rtmutex: tester: Remove the remaining BKL leftovers
  lockdep/timers: Explain in detail the locking problems del_timer_sync() may cause
  rtmutex: Simplify PI algorithm and make highest prio task get lock
  rwsem: Remove redundant asmregparm annotation
  rwsem: Move duplicate function prototypes to linux/rwsem.h
  rwsem: Unify the duplicate rwsem_is_locked() inlines
  rwsem: Move duplicate init macros and functions to linux/rwsem.h
  rwsem: Move duplicate struct rwsem declaration to linux/rwsem.h
  x86: Cleanup rwsem_count_t typedef
  rwsem: Cleanup includes
  locking: Remove deprecated lock initializers
  cred: Replace deprecated spinlock initialization
  kthread: Replace deprecated spinlock initialization
  xtensa: Replace deprecated spinlock initialization
  um: Replace deprecated spinlock initialization
  sparc: Replace deprecated spinlock initialization
  mips: Replace deprecated spinlock initialization
  cris: Replace deprecated spinlock initialization
  alpha: Replace deprecated spinlock initialization
  rtmutex-tester: Remove BKL tests

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

* 'core-futexes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  arm: Remove bogus comment in futex_atomic_cmpxchg_inatomic()
  futex: Deobfuscate handle_futex_death()
  plist: Add priority list test
  plist: Shrink struct plist_head
  futex,plist: Remove debug lock assignment from plist_node
  futex,plist: Pass the real head of the priority list to plist_del()
  futex: Sanitize futex ops argument types
  futex: Sanitize cmpxchg_futex_value_locked API
  futex: Remove redundant pagefault_disable in futex_atomic_cmpxchg_inatomic()
  futex: Avoid redudant evaluation of task_pid_vnr()
  futex: Update futex_wait_setup comments about locking

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

* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  debugobjects: Add hint for better object identification

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (57 commits)
  tidy the trailing symlinks traversal up
  Turn resolution of trailing symlinks iterative everywhere
  simplify link_path_walk() tail
  Make trailing symlink resolution in path_lookupat() iterative
  update nd->inode in __do_follow_link() instead of after do_follow_link()
  pull handling of one pathname component into a helper
  fs: allow AT_EMPTY_PATH in linkat(), limit that to CAP_DAC_READ_SEARCH
  Allow passing O_PATH descriptors via SCM_RIGHTS datagrams
  readlinkat(), fchownat() and fstatat() with empty relative pathnames
  Allow O_PATH for symlinks
  New kind of open files - "location only".
  ext4: Copy fs UUID to superblock
  ext3: Copy fs UUID to superblock.
  vfs: Export file system uuid via /proc/<pid>/mountinfo
  unistd.h: Add new syscalls numbers to asm-generic
  x86: Add new syscalls for x86_64
  x86: Add new syscalls for x86_32
  fs: Remove i_nlink check from file system link callback
  fs: Don't allow to create hardlink for deleted file
  vfs: Add open by file handle support
  ...

The new vfs locking scheme introduced in 2.6.38 breaks NFS sillyrename
because the latter relies on being able to determine the parent
directory of the dentry in the ->iput() callback in order to send the
appropriate unlink rpc call.

Looking at the code that cares about races with dput(), there doesn't
seem to be anything that specifically uses d_parent as a test for
whether or not there is a race:
  - __d_lookup_rcu(), __d_lookup() all test for d_hashed() after d_parent
  - shrink_dcache_for_umount() is safe since nothing else can rearrange
    the dentries in that super block.
  - have_submount(), select_parent() and d_genocide() can test for a
    deletion if we set the DCACHE_DISCONNECTED flag when the dentry
    is removed from the parent's d_subdirs list.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org (2.6.38, needs commit c826cb7d "dcache.c:
	create helper function for duplicated functionality" )
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This creates a helper function for he "try to ascend into the parent
directory" case, which was written out in triplicate before.  With all
the locking and subtle sequence number stuff, we really don't want to
duplicate that kind of code.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* pull the handling of current->total_link_count into
__do_follow_link()
* put the common "do ->put_link() if needed and path_put() the link"
  stuff into a helper (put_link(nd, link, cookie))
* rename __do_follow_link() to follow_link(), while we are at it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The last remaining place (resolution of nested symlink) converted
to the loop of the same kind we have in path_lookupat() and
path_openat().

Note that we still *do* have a recursion in pathname resolution;
can't avoid it, really.  However, it's strictly for nested symlinks
now - i.e. ones in the middle of a pathname.

link_path_walk() has lost the tail now - it always walks everything
except the last component.

do_follow_link() renamed to nested_symlink() and moved down.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Now that link_path_walk() is called without LOOKUP_PARENT
only from do_follow_link(), we can simplify the checks in
last component handling.  First of all, checking if we'd
arrived to a directory is not needed - the caller will check
it anyway.  And LOOKUP_FOLLOW is guaranteed to be there,
since we only get to that place with nd->depth > 0.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Now the only caller of link_path_walk() that does *not* pass
LOOKUP_PARENT is do_follow_link()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

... and note that we only need to do it for LAST_BIND symlinks
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

new helper: walk_component().  Handles everything except symlinks;
returns negative on error, 0 on success and 1 on symlinks we decided
to follow.  Drops out of RCU mode on such symlinks.

link_path_walk() and do_last() switched to using that.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

We don't want to allow creation of private hardlinks by different application
using the fd passed to them via SCM_RIGHTS. So limit the null relative name
usage in linkat syscall to CAP_DAC_READ_SEARCH
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Newer compilers (gcc 4.6) complains about:

        return ret < 0 ?: 0;

For the following reason:

  util/probe-finder.c: In function ‘probe_point_lazy_walker’:
  util/probe-finder.c:1331:18: error: the omitted middle operand in ?: will always be ‘true’, suggest explicit middle operand [-Werror=parentheses]

And indeed the return value is a somewhat obscure (but correct) value
of 'true', so return 'ret' instead - this is cleaner and unconfuses
GCC as well.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

* 'for-linus' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
  xen: suspend: remove xen_hvm_suspend
  xen: suspend: pull pre/post suspend hooks out into suspend_info
  xen: suspend: move arch specific pre/post suspend hooks into generic hooks
  xen: suspend: refactor non-arch specific pre/post suspend hooks
  xen: suspend: add "arch" to pre/post suspend hooks
  xen: suspend: pass extra hypercall argument via suspend_info struct
  xen: suspend: refactor cancellation flag into a structure
  xen: suspend: use HYPERVISOR_suspend for PVHVM case instead of open coding
  xen: switch to new schedop hypercall by default.
  xen: use new schedop interface for suspend
  xen: do not respond to unknown xenstore control requests
  xen: fix compile issue if XEN is enabled but XEN_PVHVM is disabled
  xen: PV on HVM: support PV spinlocks and IPIs
  xen: make the ballon driver work for hvm domains
  xen-blkfront: handle Xen major numbers other than XENVBD
  xen: do not use xen_info on HVM, set pv_info name to "Xen HVM"
  xen: no need to delay xen_setup_shutdown_event for hvm guests anymore

Merge branches 'stable/ia64', 'stable/blkfront-cleanup' and 'stable/cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

* 'stable/ia64' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: ia64 build broken due to "xen: switch to new schedop hypercall by default."

* 'stable/blkfront-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: Union the blkif_request request specific fields

* 'stable/cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: annotate functions which only call into __init at start of day
  xen p2m: annotate variable which appears unused
  xen: events: mark cpu_evtchn_mask_p as __refdata

* 'stable/irq.cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: events: remove dom0 specific xen_create_msi_irq
  xen: events: use xen_bind_pirq_msi_to_irq from xen_create_msi_irq
  xen: events: push set_irq_msi down into xen_create_msi_irq
  xen: events: update pirq_to_irq in xen_create_msi_irq
  xen: events: refactor xen_create_msi_irq slightly
  xen: events: separate MSI PIRQ allocation from PIRQ binding to IRQ
  xen: events: assume PHYSDEVOP_get_free_pirq exists
  xen: pci: collapse apic_register_gsi_xen_hvm and xen_hvm_register_pirq
  xen: events: return irq from xen_allocate_pirq_msi
  xen: events: drop XEN_ALLOC_IRQ flag to xen_allocate_pirq_msi
  xen: events: do not leak IRQ from xen_allocate_pirq_msi when no pirq available.
  xen: pci: only define xen_initdom_setup_msi_irqs if CONFIG_XEN_DOM0

Merge branches 'stable/irq.rework' and 'stable/pcifront-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

* 'stable/irq.rework' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/irq: Cleanup up the pirq_to_irq for DomU PV PCI passthrough guests as well.
  xen: Use IRQF_FORCE_RESUME
  xen/timer: Missing IRQF_NO_SUSPEND in timer code broke suspend.
  xen: Fix compile error introduced by "switch to new irq_chip functions"
  xen: Switch to new irq_chip functions
  xen: Remove stale irq_chip.end
  xen: events: do not free legacy IRQs
  xen: events: allocate GSIs and dynamic IRQs from separate IRQ ranges.
  xen: events: add xen_allocate_irq_{dynamic, gsi} and xen_free_irq
  xen:events: move find_unbound_irq inside CONFIG_PCI_MSI
  xen: handled remapped IRQs when enabling a pcifront PCI device.
  genirq: Add IRQF_FORCE_RESUME

* 'stable/pcifront-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  pci/xen: When free-ing MSI-X/MSI irq->desc also use generic code.
  pci/xen: Cleanup: convert int** to int[]
  pci/xen: Use xen_allocate_pirq_msi instead of xen_allocate_pirq
  xen-pcifront: Sanity check the MSI/MSI-X values
  xen-pcifront: don't use flush_scheduled_work()

Merge branches 'stable/p2m-identity.v4.9.1' and 'stable/e820' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

* 'stable/p2m-identity.v4.9.1' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/m2p: Check whether the MFN has IDENTITY_FRAME bit set..
  xen/m2p: No need to catch exceptions when we know that there is no RAM
  xen/debug: WARN_ON when identity PFN has no _PAGE_IOMAP flag set.
  xen/debugfs: Add 'p2m' file for printing out the P2M layout.
  xen/setup: Set identity mapping for non-RAM E820 and E820 gaps.
  xen/mmu: WARN_ON when racing to swap middle leaf.
  xen/mmu: Set _PAGE_IOMAP if PFN is an identity PFN.
  xen/mmu: Add the notion of identity (1-1) mapping.
  xen: Mark all initial reserved pages for the balloon as INVALID_P2M_ENTRY.

* 'stable/e820' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/e820: Don't mark balloon memory as E820_UNUSABLE when running as guest and fix overflow.
  xen/setup: Inhibit resource API from using System RAM E820 gaps as PCI mem gaps.

Just need to make sure that AF_UNIX garbage collector won't
confuse O_PATHed socket on filesystem for real AF_UNIX opened
socket.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

For readlinkat() we simply allow empty pathname; it will fail unless
we have dfd equal to O_PATH-opened symlink, so we are outside of
POSIX scope here.  For fchownat() and fstatat() we allow AT_EMPTY_PATH;
let the caller explicitly ask for such behaviour.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

At that point we can't do almost nothing with them.  They can be opened
with O_PATH, we can manipulate such descriptors with dup(), etc. and
we can see them in /proc/*/{fd,fdinfo}/*.

We can't (and won't be able to) follow /proc/*/fd/* symlinks for those;
there's simply not enough information for pathname resolution to go on
from such point - to resolve a symlink we need to know which directory
does it live in.

We will be able to do useful things with them after the next commit, though -
readlinkat() and fchownat() will be possible to use with dfd being an
O_PATH-opened symlink and empty relative pathname.  Combined with
open_by_handle() it'll give us a way to do realink-by-handle and
lchown-by-handle without messing with more redundant syscalls.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

New flag for open(2) - O_PATH.  Semantics:
	* pathname is resolved, but the file itself is _NOT_ opened
as far as filesystem is concerned.
	* almost all operations on the resulting descriptors shall
fail with -EBADF.  Exceptions are:
	1) operations on descriptors themselves (i.e.
		close(), dup(), dup2(), dup3(), fcntl(fd, F_DUPFD),
		fcntl(fd, F_DUPFD_CLOEXEC, ...), fcntl(fd, F_GETFD),
		fcntl(fd, F_SETFD, ...))
	2) fcntl(fd, F_GETFL), for a common non-destructive way to
		check if descriptor is open
	3) "dfd" arguments of ...at(2) syscalls, i.e. the starting
		points of pathname resolution
	* closing such descriptor does *NOT* affect dnotify or
posix locks.
	* permissions are checked as usual along the way to file;
no permission checks are applied to the file itself.  Of course,
giving such thing to syscall will result in permission checks (at
the moment it means checking that starting point of ....at() is
a directory and caller has exec permissions on it).

fget() and fget_light() return NULL on such descriptors; use of
fget_raw() and fget_raw_light() is needed to get them.  That protects
existing code from dealing with those things.

There are two things still missing (they come in the next commits):
one is handling of symlinks (right now we refuse to open them that
way; see the next commit for semantics related to those) and another
is descriptor passing via SCM_RIGHTS datagrams.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

File system UUID is made available to application
via  /proc/<pid>/mountinfo
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

File system UUID is made available to application
via  /proc/<pid>/mountinfo
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

We add a per superblock uuid field. File systems should
update the uuid in the fill_super callback
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This patch add new syscalls to x86_64
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

This patch adds new syscalls to x86_32
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Now that VFS check for inode->i_nlink == 0 and returns proper
error, remove similar check from file system
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>