bdi_for_each_wb() is used in several places to wake up or issue
writeback work items to all wb's (bdi_writeback's) on a given bdi.
The iteration is performed by walking bdi->cgwb_tree; however, the
tree only indexes wb's which are currently active.

For example, when a memcg gets associated with a different blkcg, the
old wb is removed from the tree so that the new one can be indexed.
The old wb starts dying from then on but will linger till all its
inodes are drained.  As these dying wb's may still host dirty inodes,
writeback operations which affect all wb's must include them.
bdi_for_each_wb() skipping dying wb's led to sync(2) missing and
failing to sync the inodes belonging to those wb's.

This patch adds a RCU protected @bdi->wb_list which lists all wb's
beloinging to that bdi.  wb's are added on creation and removed on
release rather than on the start of destruction.  bdi_for_each_wb()
usages are replaced with list_for_each[_continue]_rcu() iterations
over @bdi->wb_list and bdi_for_each_wb() and its helpers are removed.

v2: Updated as per Jan.  last_wb ref leak in bdi_split_work_to_wbs()
    fixed and unnecessary list head severing in cgwb_bdi_destroy()
    removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Artem Bityutskiy <dedekind1@gmail.com>
Fixes: ebe41ab0 ("writeback: implement bdi_for_each_wb()")
Link: http://lkml.kernel.org/g/1443012552.19983.209.camel@gmail.com
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

wakeup_dirtytime_writeback() walks and wakes up all wb's of all bdi's;
unfortunately, it was always waking up bdi->wb instead of the wb being
walked.  Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 001fe6f6 ("writeback: make wakeup_dirtytime_writeback() handle multiple bdi_writeback's")
Reviewed-by: Jan Kara <jack@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

laptop_mode_timer_fn() was using bdi_for_each_wb() without the
required RCU locking leading to the following warning.

 WARNING: CPU: 0 PID: 0 at include/linux/backing-dev.h:415 laptop_mode_timer_fn+0x106/0x170()
 ...
 Call Trace:
  <IRQ>  [<ffffffff81480cdc>] dump_stack+0x4e/0x82
  [<ffffffff81051912>] warn_slowpath_common+0x82/0xc0
  [<ffffffff81051a0a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff8115f0e6>] laptop_mode_timer_fn+0x106/0x170
  [<ffffffff810ca8e3>] call_timer_fn+0xb3/0x2f0
  [<ffffffff810cad25>] run_timer_softirq+0x205/0x370
  [<ffffffff81056854>] __do_softirq+0xd4/0x460
  [<ffffffff81056d69>] irq_exit+0x89/0xa0
  [<ffffffff8185a892>] smp_apic_timer_interrupt+0x42/0x50
  [<ffffffff81858a44>] apic_timer_interrupt+0x84/0x90
 ...

Fix it by adding rcu_read_lock() around the iteration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: a06fd6b1 ("writeback: make laptop_mode_timer_fn() handle multiple bdi_writeback's")
Reviewed-by: Jan Kara <jack@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

The timeout handling introduced in
	7e2893a1 (nbd: Fix timeout detection)
introduces a race condition which may lead to killing of tasks that are
not in nbd context anymore. This was not observed or reproducable yet.

This patch adds locking to critical use of task_recv and task_send to
avoid killing tasks that already left the NBD thread functions. This
lock is only acquired if a timeout occures or the nbd device
starts/stops.
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Reviewed-by: Ben Hutchings <ben@decadent.org.uk>
Fixes: 7e2893a1 ("nbd: Fix timeout detection")
Signed-off-by: Jens Axboe <axboe@fb.com>

Merge branch 'stable/for-jens-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus

Konrad writes:

Please git pull an update branch to your 'for-4.3/drivers' branch (which
oddly I don't see does not have the previous pull?)

 git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/for-jens-4.3

which has two fixes - one where we use the Xen blockfront EFI driver and
don't release all the requests, the other if the allocation of resources
for a particular state failed - we would go back 'Closing' and assume
that an structure would be allocated while in fact it may not be - and
crash.

xen-blkfront will crash if the check to talk_to_blkback()
in blkback_changed()(XenbusStateInitWait) returns an error.
The driver data is freed and info is set to NULL. Later during
the close process via talk_to_blkback's call to xenbus_dev_fatal()
the null pointer is passed to and dereference in blkfront_closing.

CC: stable@vger.kernel.org
Signed-off-by: Cathy Avery <cathy.avery@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Pull regmap fixes from Mark Brown:
 "A couple of fixes for the debugfs information on the register map,
  fixing issues with very small reads potentially causing underflows and
  wraparounds"

* tag 'regmap-fix-v4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: debugfs: Don't bother actually printing when calculating max length
  regmap: debugfs: Ensure we don't underflow when printing access masks

Pull spi fixes from Mark Brown:
 "A couple of very minor fixes, one for error handling in the Davinci
  driver probe function and another making the Renesas sh-msiof DT
  binding documentation correspond to what's actually implemented"

* tag 'spi-fix-v4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: sh-msiof: Match renesas,rx-fifo-size in DT bindings doc with driver
  spi: davinci: fix handling platform_get_irq result

Merge tag 'regulator-fix-v4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator

Pull regulator fixes from Mark Brown:
 "Two fixes here, one device specific fix for axp20x and a core fix for
   cases where one regulator is supplying another which broke probe
  deferral, substituting in a dummy regulator too aggressively"

* tag 'regulator-fix-v4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
  regulator: core: Handle probe deferral from DT when resolving supplies
  regulator: axp20x: Fix enable bit indexes for DCDC4 and DCDC5

Pull strscpy fixes from Chris Metcalf :
 "This patch series fixes up a couple of architecture issues where
  strscpy wasn't configured correctly (missing on h8300, duplicating
  local and asm-generic copies on powerpc and tile).

  It also adds a use of zero_bytemask() to the final store for strscpy
  to avoid writing uninitialized data to the destination.  However, to
  make this work we had to add support for zero_bytemask() to the two
  architectures that didn't have it (alpha and tile), because they were
  providing their own local copies, but didn't provide the
  zero_bytemask() that was previously only required when building with
  CONFIG_DCACHE_WORD_ACCESS"

[ Side note: there is still no actual users of strscpy except for the
  one preexisting use in arch/tile that predates the generic version.
  So this is all about fixing the infrastructure so that we eventually
  can start using it.  - Linus ]

* 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  strscpy: zero any trailing garbage bytes in the destination
  word-at-a-time.h: support zero_bytemask() on alpha and tile
  word-at-a-time.h: fix some Kbuild files

Pull MTD fixes from Brian Norris:
 "A few MTD fixes:

   - mxc_nand: a "refactoring only" change in 4.3-rc1 had some bad
     pointer (array) arithmetic.  Fix that

   - sunxi_nand:

   - Fix an old list manipulation / memory management bug in the device
     release() code path

   - Correct a few mistakes in OOB write support"

* tag 'for-linus-20151006' of git://git.infradead.org/linux-mtd:
  mxc_nand: fix copy_spare
  mtd: nand: sunxi: fix sunxi_nand_chips_cleanup()
  mtd: nand: sunxi: fix OOB handling in ->write_xxx() functions

Pull NFS client bugfixes from Trond Myklebust:
 "Highlights include:

  Bugfixes:
   - Fix a use-after-free bug in the RPC/RDMA client
   - Fix a write performance regression
   - Fix up page writeback accounting
   - Don't try to reclaim unused state owners
   - Fix a NFSv4 nograce recovery hang
   - reset states to use open_stateid when returning delegation
     voluntarily
   - Fix a tracepoint NULL-pointer dereference"

* tag 'nfs-for-4.3-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  NFS: Fix a tracepoint NULL-pointer dereference
  nfs4: reset states to use open_stateid when returning delegation voluntarily
  NFSv4: Fix a nograce recovery hang
  NFSv4.1: nfs4_opendata_check_deleg needs to handle NFS4_OPEN_CLAIM_DELEG_CUR_FH
  NFSv4: Don't try to reclaim unused state owners
  NFS: Fix a write performance regression
  NFS: Fix up page writeback accounting
  xprtrdma: disconnect and flush cqs before freeing buffers

This reverts commit 998ef75d.

The commit itself does not appear to be buggy per se, but it is exposing
a bug in ext4 (and Ted thinks ext3 too, but we solved that by getting
rid of it).  It's too late in the release cycle to really worry about
this, even if Dave Hansen has a patch that may actually fix the
underlying ext4 problem.  We can (and should) revisit this for the next
release.

The problem is that moving the prefaulting later now exposes a special
case with partially successful writes that isn't handled correctly.  And
the prefaulting likely isn't normally even that much of a performance
issue - it looks like at least one reason Dave saw this in his
performance tests is that he also ran them on Skylake that now supports
the new SMAP code, which makes the normally very cheap user space
prefaulting noticeably more expensive.
Bisected-and-acked-by: Ted Ts'o <tytso@mit.edu>
Analyzed-and-acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Running xfstest generic/013 with the tracepoint nfs:nfs4_open_file
enabled produces a NULL-pointer dereference when calculating fileid and
filehandle of the opened file.  Fix this by checking if state is NULL
before trying to use the inode pointer.
Reported-by: Olga Kornievskaia <aglo@umich.edu>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

It's possible that the destination can be shadowed in userspace
(as, for example, the perf buffers are now).  So we should take
care not to leak data that could be inspected by userspace.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

Both alpha and tile needed implementations of zero_bytemask.

The alpha version is untested.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

arch/tile added word-at-a-time.h after the patch that added generic-y
entries; the generic-y entry is now stale.

arch/h8300 is newer than the generic-y patch for word-at-a-time.h,
and needs a generic-y entry.

arch/powerpc seems to have gotten a generic-y entry by mistake in
the first patch; this change removes it.
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>

Pull xen bug fixes from David Vrabel:

 - Fix VM save performance regression with x86 PV guests

 - Make kexec work in x86 PVHVM guests (if Xen has the soft-reset ABI)

 - Other minor fixes.

* tag 'for-linus-4.3b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  x86/xen/p2m: hint at the last populated P2M entry
  x86/xen: Do not clip xen_e820_map to xen_e820_map_entries when sanitizing map
  x86/xen: Support kexec/kdump in HVM guests by doing a soft reset
  xen/x86: Don't try to write syscall-related MSRs for PV guests
  xen: use correct type for HYPERVISOR_memory_op()

Pull s390 fixes from Martin Schwidefsky:
 "Three bug fixes and an update to the default configuration"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/defconfig: set SCSI_DH=y
  s390/vtime: correct scaled cputime of partially idle CPUs
  s390/boot/decompression: disable floating point in decompressor
  s390/numa: use correct type for node_to_cpumask_map

Pull CIFS fixes from Steve French:
 "Two fixes for problems pointed out by automated tools.

  Thanks PaX/grsecurity team and Dan Carpenter (and the Smatch tool)"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  [CIFS] Update cifs version number
  [SMB3] Do not fall back to SMBWriteX in set_file_size error cases
  [SMB3] Missing null tcon check

With commit 633d6f17 (x86/xen: prepare
p2m list for memory hotplug) the P2M may be sized to accomdate a much
larger amount of memory than the domain currently has.

When saving a domain, the toolstack must scan all the P2M looking for
populated pages.  This results in a performance regression due to the
unnecessary scanning.

Instead of reporting (via shared_info) the maximum possible size of
the P2M, hint at the last PFN which might be populated.  This hint is
increased as new leaves are added to the P2M (in the expectation that
they will be used for populated entries).
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: <stable@vger.kernel.org> # 4.0+

Pull strscpy string copy function implementation from Chris Metcalf.

Chris sent this during the merge window, but I waffled back and forth on
the pull request, which is why it's going in only now.

The new "strscpy()" function is definitely easier to use and more secure
than either strncpy() or strlcpy(), both of which are horrible nasty
interfaces that have serious and irredeemable problems.

strncpy() has a useless return value, and doesn't NUL-terminate an
overlong result.  To make matters worse, it pads a short result with
zeroes, which is a performance disaster if you have big buffers.

strlcpy(), by contrast, is a mis-designed "fix" for strlcpy(), lacking
the insane NUL padding, but having a differently broken return value
which returns the original length of the source string.  Which means
that it will read characters past the count from the source buffer, and
you have to trust the source to be properly terminated.  It also makes
error handling fragile, since the test for overflow is unnecessarily
subtle.

strscpy() avoids both these problems, guaranteeing the NUL termination
(but not excessive padding) if the destination size wasn't zero, and
making the overflow condition very obvious by returning -E2BIG.  It also
doesn't read past the size of the source, and can thus be used for
untrusted source data too.

So why did I waffle about this for so long?

Every time we introduce a new-and-improved interface, people start doing
these interminable series of trivial conversion patches.

And every time that happens, somebody does some silly mistake, and the
conversion patch to the improved interface actually makes things worse.
Because the patch is mindnumbing and trivial, nobody has the attention
span to look at it carefully, and it's usually done over large swatches
of source code which means that not every conversion gets tested.

So I'm pulling the strscpy() support because it *is* a better interface.
But I will refuse to pull mindless conversion patches.  Use this in
places where it makes sense, but don't do trivial patches to fix things
that aren't actually known to be broken.

* 'strscpy' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: use global strscpy() rather than private copy
  string: provide strscpy()
  Make asm/word-at-a-time.h available on all architectures

Pull md fixes from Neil Brown:
 "Assorted fixes for md in 4.3-rc.

  Two tagged for -stable, and one is really a cleanup to match and
  improve kmemcache interface.

* tag 'md/4.3-fixes' of git://neil.brown.name/md:
  md/bitmap: don't pass -1 to bitmap_storage_alloc.
  md/raid1: Avoid raid1 resync getting stuck
  md: drop null test before destroy functions
  md: clear CHANGE_PENDING in readonly array
  md/raid0: apply base queue limits *before* disk_stack_limits
  md/raid5: don't index beyond end of array in need_this_block().
  raid5: update analysis state for failed stripe
  md: wait for pending superblock updates before switching to read-only

Pull MIPS updates from Ralf Baechle:
 "This week's round of MIPS fixes:
   - Fix JZ4740 build
   - Fix fallback to GFP_DMA
   - FP seccomp in case of ENOSYS
   - Fix bootmem panic
   - A number of FP and CPS fixes
   - Wire up new syscalls
   - Make sure BPF assembler objects can properly be disassembled
   - Fix BPF assembler code for MIPS I"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: scall: Always run the seccomp syscall filters
  MIPS: Octeon: Fix kernel panic on startup from memory corruption
  MIPS: Fix R2300 FP context switch handling
  MIPS: Fix octeon FP context switch handling
  MIPS: BPF: Fix load delay slots.
  MIPS: BPF: Do all exports of symbols with FEXPORT().
  MIPS: Fix the build on jz4740 after removing the custom gpio.h
  MIPS: CPS: #ifdef on CONFIG_MIPS_MT_SMP rather than CONFIG_MIPS_MT
  MIPS: CPS: Don't include MT code in non-MT kernels.
  MIPS: CPS: Stop dangling delay slot from has_mt.
  MIPS: dma-default: Fix 32-bit fall back to GFP_DMA
  MIPS: Wire up userfaultfd and membarrier syscalls.

Pull irq fixes from Thomas Gleixner:
 "This update contains:

   - Fix for a long standing race affecting /proc/irq/NNN

   - One line fix for ARM GICV3-ITS counting the wrong data

   - Warning silencing in ARM GICV3-ITS.  Another GCC trying to be
     overly clever issue"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3-its: Count additional LPIs for the aliased devices
  irqchip/gic-v3-its: Silence warning when its_lpi_alloc_chunks gets inlined
  genirq: Fix race in register_irq_proc()

The MIPS syscall handler code used to return -ENOSYS on invalid
syscalls. Whilst this is expected, it caused problems for seccomp
filters because the said filters never had the change to run since
the code returned -ENOSYS before triggering them. This caused
problems on the chromium testsuite for filters looking for invalid
syscalls. This has now changed and the seccomp filters are always
run even if the syscall is invalid. We return -ENOSYS once we
return from the seccomp filters. Moreover, similar codepaths have
been merged in the process which simplifies somewhat the overall
syscall code.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11236/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Update modinfo cifs.ko version number to 2.08
Signed-off-by: Steve French <steve.french@primarydata.com>

Pull x86 fixes from Ingo Molnar:
 "Fixes all around the map: W+X kernel mapping fix, WCHAN fixes, two
  build failure fixes for corner case configs, x32 header fix and a
  speling fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/headers/uapi: Fix __BITS_PER_LONG value for x32 builds
  x86/mm: Set NX on gap between __ex_table and rodata
  x86/kexec: Fix kexec crash in syscall kexec_file_load()
  x86/process: Unify 32bit and 64bit implementations of get_wchan()
  x86/process: Add proper bound checks in 64bit get_wchan()
  x86, efi, kasan: Fix build failure on !KASAN && KMEMCHECK=y kernels
  x86/hyperv: Fix the build in the !CONFIG_KEXEC_CORE case
  x86/cpufeatures: Correct spelling of the HWP_NOTIFY flag

Pull timer fixes from Ingo Molnar:
 "An abs64() fix in the watchdog driver, and two clocksource driver
  NO_IRQ assumption fixes"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource: Fix abs() usage w/ 64bit values
  clocksource/drivers/keystone: Fix bad NO_IRQ usage
  clocksource/drivers/rockchip: Fix bad NO_IRQ usage

Pull EFI fixes from Ingo Molnar:
 "Two EFI fixes: one for x86, one for ARM, fixing a boot crash bug that
  can trigger under newer EFI firmware"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64/efi: Fix boot crash by not padding between EFI_MEMORY_RUNTIME regions
  x86/efi: Fix boot crash by mapping EFI memmap entries bottom-up at runtime, instead of top-down

Pull drm fixes from Dave Airlie:
 "Bunch of fixes all over the place, all pretty small: amdgpu, i915,
  exynos, one qxl and one vmwgfx.

  There is also a bunch of mst fixes, I left some cleanups in the series
  as I didn't think it was worth splitting up the tested series"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (37 commits)
  drm/dp/mst: add some defines for logical/physical ports
  drm/dp/mst: drop cancel work sync in the mstb destroy path (v2)
  drm/dp/mst: split connector registration into two parts (v2)
  drm/dp/mst: update the link_address_sent before sending the link address (v3)
  drm/dp/mst: fixup handling hotplug on port removal.
  drm/dp/mst: don't pass port into the path builder function
  drm/radeon: drop radeon_fb_helper_set_par
  drm: handle cursor_set2 in restore_fbdev_mode
  drm/exynos: Staticize local function in exynos_drm_gem.c
  drm/exynos: fimd: actually disable dp clock
  drm/exynos: dp: remove suspend/resume functions
  drm/qxl: recreate the primary surface when the bo is not primary
  drm/amdgpu: only print meaningful VM faults
  drm/amdgpu/cgs: remove import_gpu_mem
  drm/i915: Call non-locking version of drm_kms_helper_poll_enable(), v2
  drm: Add a non-locking version of drm_kms_helper_poll_enable(), v2
  drm/vmwgfx: Fix a command submission hang regression
  drm/exynos: remove unused mode_fixup() code
  drm/exynos: remove decon_mode_fixup()
  drm/exynos: remove fimd_mode_fixup()
  ...

Pull input layer fixes from Dmitry Torokhov:
 "Fixes for two recent regressions (in Synaptics PS/2 and uinput
  drivers) and some more driver fixups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Revert "Input: synaptics - fix handling of disabling gesture mode"
  Input: psmouse - fix data race in __ps2_command
  Input: elan_i2c - add all valid ic type for i2c/smbus
  Input: zhenhua - ensure we have BITREVERSE
  Input: omap4-keypad - fix memory leak
  Input: serio - fix blocking of parport
  Input: uinput - fix crash when using ABS events
  Input: elan_i2c - expand maximum product_id form 0xFF to 0xFFFF
  Input: elan_i2c - add ic type 0x03
  Input: elan_i2c - don't require known iap version
  Input: imx6ul_tsc - fix controller name
  Input: imx6ul_tsc - use the preferred method for kzalloc()
  Input: imx6ul_tsc - check for negative return value
  Input: imx6ul_tsc - propagate the errors
  Input: walkera0701 - fix abs() calculations on 64 bit values
  Input: mms114 - remove unneded semicolons
  Input: pm8941-pwrkey - remove unneded semicolon
  Input: fix typo in MT documentation
  Input: cyapa - fix address of Gen3 devices in device tree documentation

This patch fixes one cases where abs() was being used with 64-bit
nanosecond values, where the result may be capped at 32-bits.

This potentially could cause watchdog false negatives on 32-bit
systems, so this patch addresses the issue by using abs64().
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1442279124-7309-2-git-send-email-john.stultz@linaro.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

NFS: NFSoRDMA bugfix

Fixes a use-after-free bug.
Signed-off-by: Anna Schumaker <Anna.Schumaker@netapp.com>

When the client goes to return a delegation, it should always update any
nfs4_state currently set up to use that delegation stateid to instead
use the open stateid. It already does do this in some cases,
particularly in the state recovery code, but not currently when the
delegation is voluntarily returned (e.g. in advance of a RENAME).  This
causes the client to try to continue using the delegation stateid after
the DELEGRETURN, e.g. in LAYOUTGET.

Set the nfs4_state back to using the open stateid in
nfs4_open_delegation_recall, just before clearing the
NFS_DELEGATED_STATE bit.
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Since commit 5cae02f4 an OPEN_CONFIRM should
have a privileged sequence in the recovery case to allow nograce recovery to
proceed for NFSv4.0.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>