Since 2006 we have ->i_bdev pinning bdev in question, so there's no
way to get to bdev ->evict_inode() while there's an aliasing inode
anywhere.  In other words, the only place walking the list of aliases
is guaranteed to do it only when the list is empty...

Remove the detritus; it should've been done in "[PATCH] Fix a race
condition between ->i_mapping and iput()", but nobody had noticed it
back then.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Commit 7eaceacc removed ->sync_page, but a few mentions of it still
existed in documentation and comments,
Signed-off-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

lockless_dereference() was added which can be used in place of
hard-coding smp_read_barrier_depends().
Signed-off-by: NHe Kuang <hekuang@huawei.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

- m_start() in fs/namespace.c expects that ns->event is incremented each
  time a mount added or removed from ns->list.
- umount_tree() removes items from the list but does not increment event
  counter, expecting that it's done before the function is called.
- There are some codepaths that call umount_tree() without updating
  "event" counter. e.g. from __detach_mounts().
- When this happens m_start may reuse a cached mount structure that no
  longer belongs to ns->list (i.e. use after free which usually leads
  to infinite loop).

This change fixes the above problem by incrementing global event counter
before invoking umount_tree().

Change-Id: I622c8e84dcb9fb63542372c5dbf0178ee86bb589
Cc: stable@vger.kernel.org
Signed-off-by: NAndrey Ulanov <andreyu@google.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

v9fs may be used as lower layer of overlayfs and accessing f_path.dentry
can lead to a crash.  In this case it's a NULL pointer dereference in
p9_fid_create().

Fix by replacing direct access of file->f_path.dentry with the
file_dentry() accessor, which will always return a native object.
Reported-by: NAlessio Igor Bogani <alessioigorbogani@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
Tested-by: NAlessio Igor Bogani <alessioigorbogani@gmail.com>
Fixes: 4bacc9c9 ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Cc: <stable@vger.kernel.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Add missing documentation for the d_op->d_real() method and d_real()
helper.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

The two methods essentially do the same: find the real dentry/inode
belonging to an overlay dentry.  The difference is in the usage:

vfs_open() uses ->d_select_inode() and expects the function to perform
copy-up if necessary based on the open flags argument.

file_dentry() uses ->d_real() passing in the overlay dentry as well as the
underlying inode.

vfs_rename() uses ->d_select_inode() but passes zero flags.  ->d_real()
with a zero inode would have worked just as well here.

This patch merges the functionality of ->d_select_inode() into ->d_real()
by adding an 'open_flags' argument to the latter.

[Al Viro] Make the signature of d_real() match that of ->d_real() again.
And constify the inode argument, while we are at it.
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>

Pull SCSI fixes from James Bottomley:
 "Two straightforward fixes.

  One is a concurrency issue only affecting SAS connected SATA drives,
  but which could hang the storage subsystem if it triggers (because the
  outstanding command count on error never goes back to zero) and the
  other is a NO_TAG fallout from the switch to hostwide tags which
  causes the system to crash on module insertion (we've checked
  carefully and only the 53c700 family of drivers is vulnerable to this
  issue)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  53c700: fix BUG on untagged commands
  scsi: fix race between simultaneous decrements of ->host_failed

Merge branch 'for-linus-4.7-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs fixes part 2 from Chris Mason:
 "This has one patch from Omar to bring iterate_shared back to btrfs.

  We have a tree of work we queue up for directory items and it doesn't
  lend itself well to shared access.  While we're cleaning it up, Omar
  has changed things to use an exclusive lock when there are delayed
  items"

* 'for-linus-4.7-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix ->iterate_shared() by upgrading i_rwsem for delayed nodes

Pull btrfs fixes from Chris Mason:
 "I have a two part pull this time because one of the patches Dave
  Sterba collected needed to be against v4.7-rc2 or higher (we used
  rc4).  I try to make my for-linus-xx branch testable on top of the
  last major so we can hand fixes to people on the list more easily, so
  I've split this pull in two.

  This first part has some fixes and two performance improvements that
  we've been testing for some time.

  Josef's two performance fixes are most notable.  The transid tracking
  patch makes a big improvement on pretty much every workload"

* 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: Force stripesize to the value of sectorsize
  btrfs: fix disk_i_size update bug when fallocate() fails
  Btrfs: fix error handling in map_private_extent_buffer
  Btrfs: fix error return code in btrfs_init_test_fs()
  Btrfs: don't do nocow check unless we have to
  btrfs: fix deadlock in delayed_ref_async_start
  Btrfs: track transid for delayed ref flushing

Pull sound fixes from Takashi Iwai:
 "Again pretty calm weeks: we've had only a few trivial / stable
  HD-audio fixes in addition to a possible race fix for snd-dummy driver
  spotted by syzkaller"

* tag 'sound-4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: dummy: Fix a use-after-free at closing
  ALSA: hda / realtek - add two more Thinkpad IDs (5050,5053) for tpt460 fixup
  ALSA: hda - Fix the headset mic jack detection on Dell machine
  ALSA: hda/tegra: iomem fixups for sparse warnings
  ALSA: hdac_regmap - fix the register access for runtime PM

Pull x86 kprobe fix from Thomas Gleixner:
 "A single fix clearing the TF bit when a fault is single stepped"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kprobes/x86: Clear TF bit in fault on single-stepping

Pull scheduler fixes from Thomas Gleixner:
 "A couple of scheduler fixes:

   - force watchdog reset while processing sysrq-w

   - fix a deadlock when enabling trace events in the scheduler

   - fixes to the throttled next buddy logic

   - fixes for the average accounting (missing serialization and
     underflow handling)

   - allow kernel threads for fallback to online but not active cpus"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Allow kthreads to fall back to online && !active cpus
  sched/fair: Do not announce throttled next buddy in dequeue_task_fair()
  sched/fair: Initialize throttle_count for new task-groups lazily
  sched/fair: Fix cfs_rq avg tracking underflow
  kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w
  sched/debug: Fix deadlock when enabling sched events
  sched/fair: Fix post_init_entity_util_avg() serialization

Commit fe742fd4 ("Revert "btrfs: switch to ->iterate_shared()"")
backed out the conversion to ->iterate_shared() for Btrfs because the
delayed inode handling in btrfs_real_readdir() is racy. However, we can
still do readdir in parallel if there are no delayed nodes.

This is a temporary fix which upgrades the shared inode lock to an
exclusive lock only when we have delayed items until we come up with a
more complete solution. While we're here, rename the
btrfs_{get,put}_delayed_items functions to make it very clear that
they're just for readdir.

Tested with xfstests and by doing a parallel kernel build:

	while make tinyconfig && make -j4 && git clean dqfx; do
		:
	done

along with a bunch of parallel finds in another shell:

	while true; do
		for ((i=0; i<4; i++)); do
			find . >/dev/null &
		done
		wait
	done
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NChris Mason <clm@fb.com>

Pull locking fix from Thomas Gleixner:
 "A single fix to address a race in the static key logic"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/static_key: Fix concurrent static_key_slow_inc()

Pull irq fix from Thomas Gleixner:
 "A single fix for the fallout from the conversion of MIPS GIC to irq
  domains"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/mips-gic: Fix IRQs in gic_dev_domain

Pull powerpc fixes from Michael Ellerman:
 "mm/radix (Aneesh Kumar K.V):
   - Update to tlb functions ric argument
   - Flush page walk cache when freeing page table
   - Update Radix tree size as per ISA 3.0

  mm/hash (Aneesh Kumar K.V):
   - Use the correct PPP mask when updating HPTE
   - Don't add memory coherence if cache inhibited is set

  eeh (Gavin Shan):
   - Fix invalid cached PE primary bus

  bpf/jit (Naveen N. Rao):
   - Disable classic BPF JIT on ppc64le

  .. and fix faults caused by radix patching of SLB miss handler
  (Michael Ellerman)"

* tag 'powerpc-4.7-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/bpf/jit: Disable classic BPF JIT on ppc64le
  powerpc: Fix faults caused by radix patching of SLB miss handler
  powerpc/eeh: Fix invalid cached PE primary bus
  powerpc/mm/radix: Update Radix tree size as per ISA 3.0
  powerpc/mm/hash: Don't add memory coherence if cache inhibited is set
  powerpc/mm/hash: Use the correct PPP mask when updating HPTE
  powerpc/mm/radix: Flush page walk cache when freeing page table
  powerpc/mm/radix: Update to tlb functions ric argument

Commit b235beea ("Clarify naming of thread info/stack allocators")
breaks the build on some powerpc configs, where THREAD_SIZE < PAGE_SIZE:

  kernel/fork.c:235:2: error: implicit declaration of function 'free_thread_stack'
  kernel/fork.c:355:8: error: assignment from incompatible pointer type
    stack = alloc_thread_stack_node(tsk, node);
    ^

Fix it by renaming free_stack() to free_thread_stack(), and updating the
return type of alloc_thread_stack_node().

Fixes: b235beea ("Clarify naming of thread info/stack allocators")
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

on failure d_obtain_alias() will have done iput()
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Merge misc fixes from Andrew Morton:
 "Two weeks worth of fixes here"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits)
  init/main.c: fix initcall_blacklisted on ia64, ppc64 and parisc64
  autofs: don't get stuck in a loop if vfs_write() returns an error
  mm/page_owner: avoid null pointer dereference
  tools/vm/slabinfo: fix spelling mistake: "Ocurrences" -> "Occurrences"
  fs/nilfs2: fix potential underflow in call to crc32_le
  oom, suspend: fix oom_reaper vs. oom_killer_disable race
  ocfs2: disable BUG assertions in reading blocks
  mm, compaction: abort free scanner if split fails
  mm: prevent KASAN false positives in kmemleak
  mm/hugetlb: clear compound_mapcount when freeing gigantic pages
  mm/swap.c: flush lru pvecs on compound page arrival
  memcg: css_alloc should return an ERR_PTR value on error
  memcg: mem_cgroup_migrate() may be called with irq disabled
  hugetlb: fix nr_pmds accounting with shared page tables
  Revert "mm: disable fault around on emulated access bit architecture"
  Revert "mm: make faultaround produce old ptes"
  mailmap: add Boris Brezillon's email
  mailmap: add Antoine Tenart's email
  mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask
  mm: mempool: kasan: don't poot mempool objects in quarantine
  ...

Pull rdma fixes from Doug Ledford:
 "This is the second batch of queued up rdma patches for this rc cycle.

  There isn't anything really major in here.  It's passed 0day,
  linux-next, and local testing across a wide variety of hardware.
  There are still a few known issues to be tracked down, but this should
  amount to the vast majority of the rdma RC fixes.

  Round two of 4.7 rc fixes:

   - A couple minor fixes to the rdma core
   - Multiple minor fixes to hfi1
   - Multiple minor fixes to mlx4/mlx4
   - A few minor fixes to i40iw"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma: (31 commits)
  IB/srpt: Reduce QP buffer size
  i40iw: Enable level-1 PBL for fast memory registration
  i40iw: Return correct max_fast_reg_page_list_len
  i40iw: Correct status check on i40iw_get_pble
  i40iw: Correct CQ arming
  IB/rdmavt: Correct qp_priv_alloc() return value test
  IB/hfi1: Don't zero out qp->s_ack_queue in rvt_reset_qp
  IB/hfi1: Fix deadlock with txreq allocation slow path
  IB/mlx4: Prevent cross page boundary allocation
  IB/mlx4: Fix memory leak if QP creation failed
  IB/mlx4: Verify port number in flow steering create flow
  IB/mlx4: Fix error flow when sending mads under SRIOV
  IB/mlx4: Fix the SQ size of an RC QP
  IB/mlx5: Fix wrong naming of port_rcv_data counter
  IB/mlx5: Fix post send fence logic
  IB/uverbs: Initialize ib_qp_init_attr with zeros
  IB/core: Fix false search of the IB_SA_WELL_KNOWN_GUID
  IB/core: Fix RoCE v1 multicast join logic issue
  IB/core: Fix no default GIDs when netdevice reregisters
  IB/hfi1: Send a pkey change event on driver pkey update
  ...

Pull HID fix from Jiri Kosina:
 "hiddev ioctl() validation fix from Scott Bauer"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid:
  HID: hiddev: validate num_values for HIDIOCGUSAGES, HIDIOCSUSAGES commands

Merge tag 'hwmon-for-linus-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fix from Guenter Roeck:
 "Improve fan type detection for dell-smm to prevent kernel hang"

* tag 'hwmon-for-linus-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (dell-smm) Cache fan_type() calls and change fan detection

Pull ACPI fix from Rafael Wysocki:
 "Stable-candidate fix for a deadlock in ACPICA introduced during the
  4.5 development cycle by a commit attempting to improve the handling
  of AML code that doesn't belong to any namespace objects in a given
  definition block (Lv Zheng)"

* tag 'acpi-4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPICA: Namespace: Fix deadlock triggered by MLC support in dynamic table loading

Pull power management fixes from Rafael Wysocki:
 "Fix for a latent cpufreq driver bug uncovered by a recent ACPICA
  change and several fixes for the devfreq framework, including one fix
  for an issue introduced recently.

  Specifics:

   - Fix a latent initialization issue in the pcc-cpufreq driver
     (incorrect initial value of a structure field) that has been
     uncovered by a recent ACPICA commit (Mike Galbraith).

   - Add a missing notification in an update_devfreq() error code path
     forgotten by a recent devfreq commit (Chanwoo Choi).

   - Fix devfreq device frequency initialization (Lukasz Luba).

   - Fix an incorrect IS_ERR() check in the devfreq framework discovered
     by the Smatch checker (Dan Carpenter).

   - Drop two excessive put_device() calls from the devfreq framework
     (MyungJoo Ham, Cai Zhiyong).

   - Fix a possible memory leak in the devfreq framework and drop an
     unnecessary kfree() invocation from it (MyungJoo Ham)"

* tag 'pm-4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / devfreq: Send the DEVFREQ_POSTCHANGE notification when target() is failed
  cpufreq: pcc-cpufreq: Fix doorbell.access_width
  PM / devfreq: fix initialization of current frequency in last status
  PM / devfreq: exynos-nocp: Remove incorrect IS_ERR() check
  PM / devfreq: remove double put_device
  PM / devfreq: fix double call put_device
  PM / devfreq: fix duplicated kfree on devfreq pointer
  PM / devfreq: devm_kzalloc to have dev pointer more precisely

Pull xen bug fixes from David Vrabel:

 - fix x86 PV dom0 crash during early boot on some hardware

 - fix two pciback bugs affects certain devices

 - fix potential overflow when clearing page tables in x86 PV

* tag 'for-linus-4.7b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen-pciback: return proper values during BAR sizing
  x86/xen: avoid m2p lookup when setting early page table entries
  xen/pciback: Fix conf_space read/write overlap check.
  x86/xen: fix upper bound of pmd loop in xen_cleanhighmap()
  xen/balloon: Fix declared-but-not-defined warning

Pull arm64 fixes from Will Deacon:
 "Here are a few more arm64 fixes, but things do finally appear to be
  slowing down.  The main fix is avoiding hibernation in a previously
  unanticipated situation where we have CPUs parked in the kernel, but
  it's all good stuff.

   - Fix icache/dcache sync for anonymous pages under migration
   - Correct the ASID limit check
   - Fix parallel builds of Image and Image.gz
   - Refuse to hibernate when we have CPUs that we can't offline"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: hibernate: Don't hibernate on systems with stuck CPUs
  arm64: smp: Add function to determine if cpus are stuck in the kernel
  arm64: mm: remove page_mapping check in __sync_icache_dcache
  arm64: fix boot image dependencies to not generate invalid images
  arm64: update ASID limit

When I replaced kasprintf("%pf") with a direct call to
sprint_symbol_no_offset I must have broken the initcall blacklisting
feature on the arches where dereference_function_descriptor() is
non-trivial.

Fixes: c8cdd2be (init/main.c: simplify initcall_blacklisted())
Link: http://lkml.kernel.org/r/1466027283-4065-1-git-send-email-linux@rasmusvillemoes.dkSigned-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Yang Shi <yang.shi@linaro.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__vfs_write() returns a negative value in a error case.

Link: http://lkml.kernel.org/r/20160616083108.6278.65815.stgit@pluto.themaw.netSigned-off-by: NAndrey Vagin <avagin@openvz.org>
Signed-off-by: NIan Kent <raven@themaw.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have dereferenced page_ext before checking it.  Lets check it first
and then used it.

Fixes: f86e4271 ("mm: check the return value of lookup_page_ext for all call sites")
Link: http://lkml.kernel.org/r/1465249059-7883-1-git-send-email-sudipm.mukherjee@gmail.comSigned-off-by: NSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

trivial fix to spelling mistake

Link: http://lkml.kernel.org/r/1466672144-831-1-git-send-email-colin.king@canonical.comSigned-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The value `bytes' comes from the filesystem which is about to be
mounted.  We cannot trust that the value is always in the range we
expect it to be.

Check its value before using it to calculate the length for the crc32_le
call.  It value must be larger (or equal) sumoff + 4.

This fixes a kernel bug when accidentially mounting an image file which
had the nilfs2 magic value 0x3434 at the right offset 0x406 by chance.
The bytes 0x01 0x00 were stored at 0x408 and were interpreted as a
s_bytes value of 1.  This caused an underflow when substracting sumoff +
4 (20) in the call to crc32_le.

  BUG: unable to handle kernel paging request at ffff88021e600000
  IP:  crc32_le+0x36/0x100
  ...
  Call Trace:
    nilfs_valid_sb.part.5+0x52/0x60 [nilfs2]
    nilfs_load_super_block+0x142/0x300 [nilfs2]
    init_nilfs+0x60/0x390 [nilfs2]
    nilfs_mount+0x302/0x520 [nilfs2]
    mount_fs+0x38/0x160
    vfs_kern_mount+0x67/0x110
    do_mount+0x269/0xe00
    SyS_mount+0x9f/0x100
    entry_SYSCALL_64_fastpath+0x16/0x71

Link: http://lkml.kernel.org/r/1466778587-5184-2-git-send-email-konishi.ryusuke@lab.ntt.co.jpSigned-off-by: NTorsten Hilbrich <torsten.hilbrich@secunet.com>
Tested-by: NTorsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Tetsuo has reported the following potential oom_killer_disable vs.
oom_reaper race:

 (1) freeze_processes() starts freezing user space threads.
 (2) Somebody (maybe a kenrel thread) calls out_of_memory().
 (3) The OOM killer calls mark_oom_victim() on a user space thread
     P1 which is already in __refrigerator().
 (4) oom_killer_disable() sets oom_killer_disabled = true.
 (5) P1 leaves __refrigerator() and enters do_exit().
 (6) The OOM reaper calls exit_oom_victim(P1) before P1 can call
     exit_oom_victim(P1).
 (7) oom_killer_disable() returns while P1 not yet finished
 (8) P1 perform IO/interfere with the freezer.

This situation is unfortunate.  We cannot move oom_killer_disable after
all the freezable kernel threads are frozen because the oom victim might
depend on some of those kthreads to make a forward progress to exit so
we could deadlock.  It is also far from trivial to teach the oom_reaper
to not call exit_oom_victim() because then we would lose a guarantee of
the OOM killer and oom_killer_disable forward progress because
exit_mm->mmput might block and never call exit_oom_victim.

It seems the easiest way forward is to workaround this race by calling
try_to_freeze_tasks again after oom_killer_disable.  This will make sure
that all the tasks are frozen or it bails out.

Fixes: 449d777d ("mm, oom_reaper: clear TIF_MEMDIE for all tasks queued for oom_reaper")
Link: http://lkml.kernel.org/r/1466597634-16199-1-git-send-email-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

According to some high-load testing, these two BUG assertions were
encountered, this led system panic.  Actually, there were some
discussions about removing these two BUG() assertions, it would not
bring any side effect.

Then, I did the the following changes,

1) use the existing macro CATCH_BH_JBD_RACES to wrap BUG() in the
   ocfs2_read_blocks_sync function like before.

2) disable the macro CATCH_BH_JBD_RACES in Makefile by default.

Link: http://lkml.kernel.org/r/1466574294-26863-1-git-send-email-ghe@suse.comSigned-off-by: NGang He <ghe@suse.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the memory compaction free scanner cannot successfully split a free
page (only possible due to per-zone low watermark), terminate the free
scanner rather than continuing to scan memory needlessly.  If the
watermark is insufficient for a free page of order <= cc->order, then
terminate the scanner since all future splits will also likely fail.

This prevents the compaction freeing scanner from scanning all memory on
very large zones (very noticeable for zones > 128GB, for instance) when
all splits will likely fail while holding zone->lock.

compaction_alloc() iterating a 128GB zone has been benchmarked to take
over 400ms on some systems whereas any free page isolated and ready to
be split ends up failing in split_free_page() because of the low
watermark check and thus the iteration continues.

The next time compaction occurs, the freeing scanner will likely start
at the end of the zone again since no success was made previously and we
get the same lengthy iteration until the zone is brought above the low
watermark.  All thp page faults can take >400ms in such a state without
this fix.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1606211820350.97086@chino.kir.corp.google.comSigned-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>