When the client is reading or writing using pNFS, and hits an error
on the DS, then it typically sends a LAYOUTERROR and/or LAYOUTRETURN
to the MDS, before redirtying the failed pages, and going for a new
round of reads/writebacks. The problem is that if the server has no
way to fix the DS, then we may need a way to interrupt this loop
after a set number of attempts have been made.
This patch adds an optional module parameter that allows the admin
to specify how many times to retry the read/writeback process before
failing with a fatal error.
The default behaviour is to retry forever.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

All the callers of nfs_create_request() are now creating page group
heads, so we can remove the redundant 'last' page argument.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

We require all NFS I/O subrequests to duplicate the lock context as well
as the open context.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Replace the NFS custom error reporting mechanism with the generic
mapping_set_error().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

vfs_fsync() has the side effect of clearing unreported writeback errors,
so we need to make sure that we do not abuse it in situations where
applications might not normally expect us to report those errors.

The solution is to replace calls to vfs_fsync() with calls to nfs_wb_all().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The NFS read code can trigger writeback while holding the page lock.
If an error then triggers a call to nfs_write_error_remove_page(),
we can deadlock.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

When flushing out dirty pages, the fact that we may hit fatal errors
is not a reason to stop writeback. Those errors are reported through
fsync(), not through the flush mechanism.

Fixes: a6598813 ("NFS: Don't write back further requests if there...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Add a mount option that exposes the ETIMEDOUT errors that occur during
soft timeouts to the application. This allows aware applications to
distinguish between server disk IO errors and client timeout errors.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

When the label says "for internal use only", then it doesn't belong
in the 'uapi' subtree.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

When we introduce the 'softerr' mount option, we will see the RPC
layer returning ETIMEDOUT errors if the server is unresponsive. We
want to consider those errors to be fatal on par with the EIO errors
that are returned by ordinary 'soft' timeouts..
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Add the 'softerr' rpc client flag that sets the RPC_TASK_TIMEOUT
flag on all new rpc tasks that are attached to that rpc client.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

In particular, the timeout messages can be very noisy, so we ought to
ratelimit them in order to avoid spamming the syslog.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

When calculating the major timeout for a new task, when we know that the
connection has been broken, use the task->tk_start to ensure that we also
take into account the time spent waiting for a slot or session slot. This
ensures that we fail over soft requests relatively quickly once the
connection has actually been broken, and the first requests have
started to fail.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

If a soft NFSv4 request is sent, then we don't need it to time out unless
the connection breaks. The reason is that as long as the connection is
unbroken, the protocol states that the server is not allowed to drop the
request.  IOW: as long as the connection remains unbroken, the client may
assume that all transmitted RPC requests are being processed by the server,
and that retransmissions and timeouts of those requests are unwarranted.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Add variables to track RPC level errors so that we can distinguish
between issue that arose in the RPC transport layer as opposed to
those arising from the reply message.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Ensure that when in the transport layer, we don't sleep past
a major timeout.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Don't wake idle CPUs only for the purpose of servicing an RPC
queue timeout.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Simplify the setting of queue timeouts by using the timer_reduce()
function.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Add a helper to ensure that debugfs and friends print out the
correct current task timeout value.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up the RPC task sleep interfaces by replacing the task->tk_timeout
'hidden parameter' to rpc_sleep_on() with a new function that takes an
absolute timeout.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

None of the callers set the 'action' argument, so let's just remove it.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

rpc_sleep_on() does not need to set the task->tk_callback under the
queue lock, so move that out.
Also refactor the check for whether the task is active.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Convert the transport callback to actually put the request to sleep
instead of just setting a timeout. This is in preparation for
rpc_sleep_on_timeout().
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The RPC_TASK_KILLED flag should really not be set from another context
because it can clobber data in the struct task when task->tk_flags is
changed non-atomically.
Let's therefore swap out RPC_TASK_KILLED with an atomic flag, and add
a function to set that flag and safely wake up the task.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull NFS client bugfix from Trond Myklebust:
 "Fix a regression in which an RPC call can be tagged with an error
  despite the transmission being successful"

* tag 'nfs-for-5.1-5' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  SUNRPC: Ignore queue transmission errors on successful transmission

Pull SCSI fixes from James Bottomley:
 "Three minor fixes: two obvious ones in drivers and a fix to the SG_IO
  path to correctly return status on error"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: aic7xxx: fix EISA support
  Revert "scsi: fcoe: clear FC_RP_STARTED flags when receiving a LOGO"
  scsi: core: set result when the command cannot be dispatched

Pull block fixes from Jens Axboe:
 "A set of small fixes that should go into this series. This contains:

   - Removal of unused queue member (Hou)

   - Overflow bvec fix (Ming)

   - Various little io_uring tweaks (me)
       - kthread parking
       - Only call cpu_possible() for verified CPU
       - Drop unused 'file' argument to io_file_put()
       - io_uring_enter vs io_uring_register deadlock fix
       - CQ overflow fix

   - BFQ internal depth update fix (me)"

* tag 'for-linus-20190420' of git://git.kernel.dk/linux-block:
  block: make sure that bvec length can't be overflow
  block: kill all_q_node in request_queue
  io_uring: fix CQ overflow condition
  io_uring: fix possible deadlock between io_uring_{enter,register}
  io_uring: drop io_file_put() 'file' argument
  bfq: update internal depth state when queue depth changes
  io_uring: only test SQPOLL cpu after we've verified it
  io_uring: park SQPOLL thread if it's percpu

Pill i3c fixes from Boris Brezillon:

 - fix the random PID check

 - fix the disable controller logic in the designware driver

 - fix I3C entry in MAINTAINERS

* tag 'i3c/fixes-for-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
  MAINTAINERS: Fix the I3C entry
  i3c: dw: Fix dw_i3c_master_disable controller by using correct mask
  i3c: Fix the verification of random PID

Pull sound fixes from Takashi Iwai:
 "Two core fixes for long-standing bugs for the races at concurrent
  device creation and deletion that were (unsurprisingly) spotted by
  syzkaller with usb-fuzzer.

  The rest are usual small HD-audio fixes"

* tag 'sound-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda/realtek - add two more pin configuration sets to quirk table
  ALSA: core: Fix card races between register and disconnect
  ALSA: info: Fix racy addition/deletion of nodes
  ALSA: hda: Initialize power_state field properly

Pull timer fixes from Ingo Molnar:
 "Misc clocksource driver fixes, and a sched-clock wrapping fix"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers/sched_clock: Prevent generic sched_clock wrap caused by tick_freeze()
  clocksource/drivers/timer-ti-dm: Remove omap_dm_timer_set_load_start
  clocksource/drivers/oxnas: Fix OX820 compatible
  clocksource/drivers/arm_arch_timer: Remove unneeded pr_fmt macro
  clocksource/drivers/npcm: select TIMER_OF

Pull perf fixes from Ingo Molnar:
 "Misc fixes:
   - various tooling fixes
   - kretprobe fixes
   - kprobes annotation fixes
   - kprobes error checking fix
   - fix the default events for AMD Family 17h CPUs
   - PEBS fix
   - AUX record fix
   - address filtering fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kprobes: Avoid kretprobe recursion bug
  kprobes: Mark ftrace mcount handler functions nokprobe
  x86/kprobes: Verify stack frame on kretprobe
  perf/x86/amd: Add event map for AMD Family 17h
  perf bpf: Return NULL when RB tree lookup fails in perf_env__find_btf()
  perf tools: Fix map reference counting
  perf evlist: Fix side band thread draining
  perf tools: Check maps for bpf programs
  perf bpf: Return NULL when RB tree lookup fails in perf_env__find_bpf_prog_info()
  tools include uapi: Sync sound/asound.h copy
  perf top: Always sample time to satisfy needs of use of ordered queuing
  perf evsel: Use hweight64() instead of hweight_long(attr.sample_regs_user)
  tools lib traceevent: Fix missing equality check for strcmp
  perf stat: Disable DIR_FORMAT feature for 'perf stat record'
  perf scripts python: export-to-sqlite.py: Fix use of parent_id in calls_view
  perf header: Fix lock/unlock imbalances when processing BPF/BTF info
  perf/x86: Fix incorrect PEBS_REGS
  perf/ring_buffer: Fix AUX record suppression
  perf/core: Fix the address filtering fix
  kprobes: Fix error check when reusing optimized probes

Pull x86 fixes from Ingo Molnar:
 "Misc fixes all over the place: a console spam fix, section attributes
  fixes, a KASLR fix, a TLB stack-variable alignment fix, a reboot
  quirk, boot options related warnings fix, an LTO fix, a deadlock fix
  and an RDT fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/cpu/intel: Lower the "ENERGY_PERF_BIAS: Set to normal" message's log priority
  x86/cpu/bugs: Use __initconst for 'const' init data
  x86/mm/KASLR: Fix the size of the direct mapping section
  x86/Kconfig: Fix spelling mistake "effectivness" -> "effectiveness"
  x86/mm/tlb: Revert "x86/mm: Align TLB invalidation info"
  x86/reboot, efi: Use EFI reboot for Acer TravelMate X514-51T
  x86/mm: Prevent bogus warnings with "noexec=off"
  x86/build/lto: Fix truncated .bss with -fdata-sections
  x86/speculation: Prevent deadlock on ssb_state::lock
  x86/resctrl: Do not repeat rdtgroup mode initialization

Pull scheduler fixes from Ingo Molnar:
 "A deadline scheduler warning/race fix, and a cfs_period_us quota
  calculation workaround where the real fix looks too involved to merge
  immediately"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/deadline: Correctly handle active 0-lag timers
  sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup

Pull locking fixes from Ingo Molnar:
 "A lockdep warning fix and a script execution fix when atomics are
  generated"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/atomics: Don't assume that scripts are executable
  locking/lockdep: Make lockdep_unregister_key() honor 'debug_locks' again

Pull cgroup fix from Tejun Heo:
 "A patch to fix a RCU imbalance error in the devices cgroup
  configuration error path"

* 'for-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  device_cgroup: fix RCU imbalance in error case

Pull percpu fixlet from Dennis Zhou:
 "This stops printing the base address of percpu memory on
  initialization"

* 'for-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
  percpu: stop printing kernel addresses

Pull tty/serial fixes from Greg KH:
 "Here are five small fixes for some tty/serial/vt issues that have been
  reported.

  The vt one has been around for a while, it is good to finally get that
  resolved. The others fix a build warning that showed up in 5.1-rc1,
  and resolve a problem in the sh-sci driver.

  Note, the second patch for build warning fix for the sc16is7xx driver
  was just applied to the tree, as it resolves a problem with the
  previous patch to try to solve the issue. It has not shown up in
  linux-next yet, unlike all of the other patches, but it has passed
  0-day testing and everyone seems to agree that it is correct"

* tag 'tty-5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  sc16is7xx: put err_spi and err_i2c into correct #ifdef
  vt: fix cursor when clearing the screen
  sc16is7xx: move label 'err_spi' to correct section
  serial: sh-sci: Fix HSCIF RX sampling point adjustment
  serial: sh-sci: Fix HSCIF RX sampling point calculation

Merge misc fixes from Andrew Morton:
 "16 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping
  mm/kmemleak.c: fix unused-function warning
  init: initialize jump labels before command line option parsing
  kernel/watchdog_hld.c: hard lockup message should end with a newline
  kcov: improve CONFIG_ARCH_HAS_KCOV help text
  mm: fix inactive list balancing between NUMA nodes and cgroups
  mm/hotplug: treat CMA pages as unmovable
  proc: fixup proc-pid-vm test
  proc: fix map_files test on F29
  mm/vmstat.c: fix /proc/vmstat format for CONFIG_DEBUG_TLBFLUSH=y CONFIG_SMP=n
  mm/memory_hotplug: do not unlock after failing to take the device_hotplug_lock
  mm: swapoff: shmem_unuse() stop eviction without igrab()
  mm: swapoff: take notice of completion sooner
  mm: swapoff: remove too limiting SWAP_UNUSE_MAX_TRIES
  mm: swapoff: shmem_find_swap_entries() filter out other types
  slab: store tagged freelist for off-slab slabmgmt