Commit df2cb6da ("block: Avoid deadlocks with bio allocation by
stacking drivers") created a workqueue for every bio set and code
in bio_alloc_bioset() that tries to resolve some low-memory deadlocks
by redirecting bios queued on current->bio_list to the workqueue if the
system is low on memory.  However other deadlocks (see below **) may
happen, without any low memory condition, because generic_make_request
is queuing bios to current->bio_list (rather than submitting them).

** the related dm-snapshot deadlock is detailed here:
https://www.redhat.com/archives/dm-devel/2016-July/msg00065.html

Fix this deadlock by redirecting any bios on current->bio_list to the
bio_set's rescue workqueue on every schedule() call.  Consequently,
when the process blocks on a mutex, the bios queued on
current->bio_list are dispatched to independent workqueus and they can
complete without waiting for the mutex to be available.

The structure blk_plug contains an entry cb_list and this list can contain
arbitrary callback functions that are called when the process blocks.
To implement this fix DM (ab)uses the onstack plug's cb_list interface
to get its flush_current_bio_list() called at schedule() time.

This fixes the snapshot deadlock - if the map method blocks,
flush_current_bio_list() will be called and it redirects bios waiting
on current->bio_list to appropriate workqueues.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1267650
Depends-on: df2cb6da ("block: Avoid deadlocks with bio allocation by stacking drivers")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The sloppy nature of lockless access to percpu pointers
(s->current_path) in rr_select_path(), from multiple threads, is
causing some paths to used more than others -- which results in less
IO performance being observed.

Revert these upstream commits to restore truly symmetric round-robin
IO submission in DM multipath:

b0b477c7 dm round robin: use percpu 'repeat_count' and 'current_path'
802934b2 dm round robin: do not use this_cpu_ptr() without having preemption disabled

There is no benefit to all this complexity if repeat_count = 1 (which is
the recommended default).

Cc: stable@vger.kernel.org # 4.6+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Fixes: dfcfac3e ("dm stats: collect and report histogram of IO latencies")
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Declare dm_space_map structures as const as they are only passed as an
argument to the function memcpy. This argument is of type const void *,
so dm_space_map structures having this property can be declared as
const.

File size before:
   text	   data	    bss	    dec	    hex	filename
   4889	    240	      0	   5129	   1409 dm-space-map-metadata.o

File size after:
   text	   data	    bss	    dec	    hex	filename
   5139	      0	      0	   5139	   1413 dm-space-map-metadata.o
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Big speed up with large configs.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

A more efficient way of creating a populated bitset.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Improves __load_mapping_v1() and __load_mapping_v2() DMERR messages to
explicitly name the cache block number whose mapping couldn't be
loaded.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

If "metadata2" is provided as a table argument when creating/loading a
cache target a more compact metadata format, with separate dirty bits,
is used.  "metadata2" improves speed of shutting down a cache target.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm_btree_del() is called from an ioctl so don't recurse into FS.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The metadata_space_map_root passed to sm_ll_open_metadata() may or may
not be arch aligned, use memcpy to ensure it is.  This is not a fast
path so the extra memcpy doesn't hurt us.

Long-term it'd be better to use the kernel's alignment infrastructure to
remove the memcpy()s that are littered across persistent-data (btree,
array, space-maps, etc).
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

A rounding bug due to compiler generated temporary being 32bit was found
in remap_to_cache().  A localized cast in remap_to_cache() fixes the
corruption but this preferred fix (changing from uint32_t to sector_t)
eliminates potential for future rounding errors elsewhere.

Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

For consistency, call read_disk_sb() from
attempt_restore_of_faulty_devices() instead
of calling sync_page_io() directly.

Explicitly set device to faulty on superblock read error.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Add md raid4/5/6 journaling support (upstream commit bac624f3 started
the implementation) which closes the write hole (i.e. non-atomic updates
to stripes) using a dedicated journal device.

Background:
raid4/5/6 stripes hold N data payloads per stripe plus one parity raid4/5
or two raid6 P/Q syndrome payloads in an in-memory stripe cache.
Parity or P/Q syndromes used to recover any data payloads in case of a disk
failure are calculated from the N data payloads and need to be updated on the
different component devices of the raid device.  Those are non-atomic,
persistent updates.  Hence a crash can cause failure to update all stripe
payloads persistently and thus cause data loss during stripe recovery.
This problem gets addressed by writing whole stripe cache entries (together with
journal metadata) to a persistent journal entry on a dedicated journal device.
Only if that journal entry is written successfully, the stripe cache entry is
updated on the component devices of the raid device (i.e. writethrough type).
In case of a crash, the entry can be recovered from the journal and be written
again thus ensuring consistent stripe payload suitable to data recovery.

Future dependencies:
once writeback caching being worked on to compensate for the throughput
implictions involved with writethrough overhead is supported with journaling
in upstream, an additional patch based on this one will support it in dm-raid.

Journal resilience related remarks:
because stripes are recovered from the journal in case of a crash, the
journal device better be resilient.  Resilience becomes mandatory with
future writeback support, because loosing the working set in the log
means data loss as oposed to writethrough, were the loss of the
journal device 'only' reintroduces the write hole.

Fix comment on data offsets in parse_dev_params() and initialize
new_data_offset as well.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

During raid set resize checks and setting up the recovery offset in case a raid
set grows, calculated rd->md.dev_sectors is compared to rs->dev[0].rdev.sectors.

Device 0 may not be defined in case userspace passes in '- -' for it
(lvm2 doesn't do that so far), thus it's device sectors can't be taken
authoritatively in this comparison and another valid device must be used
to retrieve the device size.

Use mddev->dev_sectors in checking for ongoing recovery for the same reason.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

This fix addresses the following 3 failure scenarios:

1) If a (transiently) inaccessible metadata device is being passed into the
constructor (e.g. a device tuple '254:4 254:5'), it is processed as if
'- -' was given.  This erroneously results in a status table line containing
'- -', which mistakenly differs from what has been passed in.  As a result,
userspace libdevmapper puts the device tuple seperate from the RAID device
thus not processing the dependencies properly.

2) False health status char 'A' instead of 'D' is emitted on the status
status info line for the meta/data device tuple in this metadata device
failure case.

3) If the metadata device is accessible when passed into the constructor
but the data device (partially) isn't, that leg may be set faulty by the
raid personality on access to the (partially) unavailable leg.  Restore
tried in a second raid device resume on such failed leg (status char 'D')
fails after the (partial) leg returned.

Fixes for aforementioned failure scenarios:

- don't release passed in devices in the constructor thus allowing the
  status table line to e.g. contain '254:4 254:5' rather than '- -'

- emit device status char 'D' rather than 'A' for the device tuple
  with the failed metadata device on the status info line

- when attempting to restore faulty devices in a second resume, allow the
  device hot remove function to succeed by setting the device to not in-sync

In case userspace intentionally passes '- -' into the constructor to avoid that
device tuple (e.g. to split off a raid1 leg temporarily for later re-addition),
the status table line will correctly show '- -' and the status info line will
provide a '-' device health character for the non-defined device tuple.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Pull x86 fix from Thomas Gleixner:
 "Restore the retrigger callbacks in the IO APIC irq chips. That
  addresses a long standing regression which got introduced with the
  rewrite of the x86 irq subsystem two years ago and went unnoticed so
  far"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ioapic: Restore IO-APIC irq_chip retrigger callback

Pull smp/hotplug fix from Thomas Gleixner:
 "Remove an unused variable which is a leftover from the notifier
  removal"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Remove unused but set variable in _cpu_down()

Pull virtio/vhost fixes from Michael Tsirkin:
 "Random fixes and cleanups that accumulated over the time"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio/s390: virtio: constify virtio_config_ops structures
  virtio/s390: add missing \n to end of dev_err message
  virtio/s390: support READ_STATUS command for virtio-ccw
  tools/virtio/ringtest: tweaks for s390
  tools/virtio/ringtest: fix run-on-all.sh for offline cpus
  virtio_console: fix a crash in config_work_handler
  vhost/scsi: silence uninitialized variable warning
  vhost: scsi: constify target_core_fabric_ops structures

Pull thermal management fixes from Zhang Rui:

 - fix a regression that thermal zone dynamically allocated sysfs
   attributes are freed before they're removed, which is introduced in
   4.10-rc1 (Jacob von Chorus)

 - fix a boot warning because deprecated hwmon API is used (Fabio
   Estevam)

 - a couple of fixes for rockchip thermal driver (Brian Norris, Caesar
   Wang)

* 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
  thermal: rockchip: fixes the conversion table
  thermal: core: move tz->device.groups cleanup to thermal_release
  thermal: thermal_hwmon: Convert to hwmon_device_register_with_info()
  thermal: rockchip: handle set_trips without the trip points
  thermal: rockchip: optimize the conversion table
  thermal: rockchip: fixes invalid temperature case
  thermal: rockchip: don't pass table structs by value
  thermal: rockchip: improve conversion error messages

Pull USB fixes from Greg KH:
 "Here are a few small USB fixes for 4.10-rc5.

  Most of these are gadget/dwc2 fixes for reported issues, all of these
  have been in linux-next for a while. The last one is a single xhci
  WARN_ON removal to handle an issue that the dwc3 driver is hitting in
  the 4.10-rc tree. The warning is harmless and needs to be removed, and
  a "real" fix that is more complex will show up in 4.11-rc1 for this
  device.

  That last patch hasn't been in linux-next yet due to the weekend
  timing, but it's a "simple" WARN_ON() removal so what could go wrong?
  :)"

Famous last words.

* tag 'usb-4.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  xhci: remove WARN_ON if dma mask is not set for platform devices
  usb: dwc2: host: fix Wmaybe-uninitialized warning
  usb: dwc2: gadget: Fix GUSBCFG.USBTRDTIM value
  usb: gadget: udc: atmel: remove memory leak
  usb: dwc3: exynos fix axius clock error path to do cleanup
  usb: dwc2: Avoid suspending if we're in gadget mode
  usb: dwc2: use u32 for DT binding parameters
  usb: gadget: f_fs: Fix iterations on endpoints.
  usb: dwc2: gadget: Fix DMA memory freeing
  usb: gadget: composite: Fix function used to free memory

Pull libnvdimm fixes from Dan Williams:
 "Two fixes:

   - a regression fix for the multiple-pmem-namespace-per-region support
     added in 4.9. Even if an existing environment is not using that
     feature the act of creating and a destroying a single namespace
     with the ndctl utility will lead to the proliferation of extra
     unwanted namespace devices.

   - a fix for the error code returned from the pmem driver when the
     memcpy_mcsafe() routine returns -EFAULT. Btrfs seems to be the only
     block I/O consumer that tries to parse the meaning of the error
     code when it is non-zero.

  Neither of these fixes are critical, the namespace leak is awkward in
  that it can cause device naming to change and complicates debugging
  namespace initialization issues. The error code fix is included out of
  caution for what other consumers might be expecting -EIO for block I/O
  errors"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, namespace: fix pmem namespace leak, delete when size set to zero
  pmem: return EIO on read_pmem() failure

Pull clk fix from Stephen Boyd:
 "One fix for Samsung Exynos524x SoCs where recent IOMMU patches have
  caused some of these clocks to turn off when they were always left on
  before"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk/samsung: exynos542x: mark some clocks as critical

Pull ARC fixes from Vineet Gupta:

 - more intc updates [Yuriv]

 - fix module build when unwinder is turned off

 - IO Coherency Programming model updates

 - other miscellaneous

* tag 'arc-4.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: Revert "ARC: mm: IOC: Don't enable IOC by default"
  ARC: mm: split arc_cache_init to allow __init reaping of bulk
  ARCv2: IOC: Use actual memory size to setup aperture size
  ARCv2: IOC: Adhere to progamming model guidelines to avoid DMA corruption
  ARCv2: IOC: refactor the IOC and SLC operations into own functions
  ARC: module: Fix !CONFIG_ARC_DW2_UNWIND builds
  ARCv2: save r30 on kernel entry as gcc uses it for code-gen
  ARCv2: IRQ: Call entry/exit functions for chained handlers in MCIP
  ARC: IRQ: Use hwirq instead of virq in mask/unmask
  ARC: mmu: clarify the MMUv3 programming model

Pull powerpc fixes from Michael Ellerman:
 "Two fixes for fallout from the hugetlb changes we merged this cycle.

  Ten other fixes, four only affect Power9, and the rest are a bit of a
  mixture though nothing terrible.

  Thanks to: Aneesh Kumar K.V, Anton Blanchard, Benjamin Herrenschmidt,
  Dave Martin, Gavin Shan, Madhavan Srinivasan, Nicholas Piggin, Reza
  Arbab"

* tag 'powerpc-4.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc: Ignore reserved field in DCSR and PVR reads and writes
  powerpc/ptrace: Preserve previous TM fprs/vsrs on short regset write
  powerpc/ptrace: Preserve previous fprs/vsrs on short regset write
  powerpc/perf: Use MSR to report privilege level on P9 DD1
  selftest/powerpc: Wrong PMC initialized in pmc56_overflow test
  powerpc/eeh: Enable IO path on permanent error
  powerpc/perf: Fix PM_BRU_CMPL event code for power9
  powerpc/mm: Fix little-endian 4K hugetlb
  powerpc/mm/hugetlb: Don't panic when we don't find the default huge page size
  powerpc: Fix pgtable pmd cache init
  powerpc/icp-opal: Fix missing KVM case and harden replay
  powerpc/mm: Fix memory hotplug BUG() on radix

Pull KVM fixes from Radim Krčmář:
 "ARM:
   - Fix for timer setup on VHE machines
   - Drop spurious warning when the timer races against the vcpu running
     again
   - Prevent a vgic deadlock when the initialization fails (for stable)

  s390:
   - Fix a kernel memory exposure (for stable)

  x86:
   - Fix exception injection when hypercall instruction cannot be
     patched"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: s390: do not expose random data via facility bitmap
  KVM: x86: fix fixing of hypercalls
  KVM: arm/arm64: vgic: Fix deadlock on error handling
  KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems
  KVM: arm/arm64: Fix occasional warning from the timer work function

Merge branch 'scsi-target-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bvanassche/linux

Pull SCSI target fixes from Bart Van Assche:

 - two small fixes for the ibmvscsis driver

 - ten patches with bug fixes for the target mode of the qla2xxx driver

 - four patches that avoid that the "sparse" and "smatch" static
   analyzer tools report false positives for the qla2xxx code base

* 'scsi-target-for-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/bvanassche/linux:
  qla2xxx: Disable out-of-order processing by default in firmware
  qla2xxx: Fix erroneous invalid handle message
  qla2xxx: Reduce exess wait during chip reset
  qla2xxx: Terminate exchange if corrupted
  qla2xxx: Fix crash due to null pointer access
  qla2xxx: Collect additional information to debug fw dump
  qla2xxx: Reset reserved field in firmware options to 0
  qla2xxx: Set tcm_qla2xxx version to automatically track qla2xxx version
  qla2xxx: Include ATIO queue in firmware dump when in target mode
  qla2xxx: Fix wrong IOCB type assumption
  qla2xxx: Avoid that building with W=1 triggers complaints about set-but-not-used variables
  qla2xxx: Move two arrays from header files to .c files
  qla2xxx: Declare an array with file scope static
  qla2xxx: Fix indentation
  ibmvscsis: Fix sleeping in interrupt context
  ibmvscsis: Fix max transfer length

Pull block fixes from Jens Axboe:
 "Just two small fixes for this -rc.

  One is just killing an unused variable from Keith, but the other
  fixes a performance regression for nbd in this series, where we
  inadvertently flipped when we set MSG_MORE when outputting data"

* 'for-linus' of git://git.kernel.dk/linux-block:
  nbd: only set MSG_MORE when we have more to send
  blk-mq: Remove unused variable

Pull spi fixes from Mark Brown:
 "The usual small smattering of driver specific fixes. A few bits that
  stand out here:

   - the R-Car patches adding fallbacks are just adding new compatible
     strings to the driver so that device trees are written in a more
     robustly future proof fashion, this isn't strictly a fix but it's
     just new IDs and it's better to get it into mainline sooner to
     improve the ABI

   - the DesignWare "switch to new API part 2" patch is actually a
     misleadingly titled fix for a bit that got missed in the original
     conversion"

* tag 'spi-fix-v4.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
  spi: davinci: use dma_mapping_error()
  spi: spi-axi: Free resources on error path
  spi: pxa2xx: add missed break
  spi: dw-mid: switch to new dmaengine_terminate_* API (part 2)
  spi: dw: Make debugfs name unique between instances
  spi: sh-msiof: Do not use C++ style comment
  spi: armada-3700: Set mode bits correctly
  spi: armada-3700: fix unsigned compare than zero on irq
  spi: sh-msiof: Add R-Car Gen 2 and 3 fallback bindings
  spi: SPI_FSL_DSPI should depend on HAS_DMA

Pull ceph fixes from Ilya Dryomov:
 "Three filesystem endianness fixes (one goes back to the 2.6 era, all
  marked for stable) and two fixups for this merge window's patches"

* tag 'ceph-for-4.10-rc5' of git://github.com/ceph/ceph-client:
  ceph: fix bad endianness handling in parse_reply_info_extra
  ceph: fix endianness bug in frag_tree_split_cmp
  ceph: fix endianness of getattr mask in ceph_d_revalidate
  libceph: make sure ceph_aes_crypt() IV is aligned
  ceph: fix ceph_get_caps() interruption

Pull overlayfs fix from Miklos Szeredi:
 "This fixes a regression introduced in this cycle"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: fix possible use after free on redirect dir lookup

Pull fuse fixes from Miklos Szeredi:
 "Fix two regressions, one introduced in 4.9 and a less recent one in
  4.2"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: fix time_to_jiffies nsec sanity check
  fuse: clear FR_PENDING flag when moving requests out of pending queue

Pull SCSI fixes from James Bottomley:
 "This is a set of 12 fixes including the mpt3sas one that was causing
  hangs on ATA passthrough.

  The others are a couple of zoned block device fixes, a SAS device
  detection bug which lead to SATA drives not being matched to bays, two
  qla2xxx MSI fixes, a qla2xxx req for rsp confusion caused by cut and
  paste, and a few other minor fixes"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: mpt3sas: fix hang on ata passthrough commands
  scsi: lpfc: Set elsiocb contexts to NULL after freeing it
  scsi: sd: Ignore zoned field for host-managed devices
  scsi: sd: Fix wrong DPOFUA disable in sd_read_cache_type
  scsi: bfa: fix wrongly initialized variable in bfad_im_bsg_els_ct_request()
  scsi: ses: Fix SAS device detection in enclosure
  scsi: libfc: Fix variable name in fc_set_wwpn
  scsi: lpfc: avoid double free of resource identifiers
  scsi: qla2xxx: remove irq_affinity_notifier
  scsi: qla2xxx: fix MSI-X vector affinity
  scsi: qla2xxx: Fix apparent cut-n-paste error.
  scsi: qla2xxx: Get mutex lock before checking optrom_state