Introduce a new target that is meant for file system developers to test file
system integrity at particular points in the life of a file system.  We capture
all write requests and associated data and log them to a separate device
for later replay.  There is a userspace utility to do this replay.  The
idea behind this is to give file system developers a tool to verify that
the file system is always consistent.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Zach Brown <zab@zabbo.net>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Use the normal return values for bool functions.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Add device specific modes to dm-verity to specify how corrupted
blocks should be handled.  The following modes are defined:

  - DM_VERITY_MODE_EIO is the default behavior, where reading a
    corrupted block results in -EIO.

  - DM_VERITY_MODE_LOGGING only logs corrupted blocks, but does
    not block the read.

  - DM_VERITY_MODE_RESTART calls kernel_restart when a corrupted
    block is discovered.

In addition, each mode sends a uevent to notify userspace of
corruption and to allow further recovery actions.

The driver defaults to previous behavior (DM_VERITY_MODE_EIO)
and other modes can be enabled with an additional parameter to
the verity table.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The 'trim' message wasn't ever implemented.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Converting milliseconds to jiffies by "val * HZ / 1000" is technically
OK but msecs_to_jiffies(val) is the cleaner solution and handles all
corner cases correctly.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

This fixes up a compile warning [-Wunused-but-set-variable] - given the
comment in userspace_set_region_sync() the non-reporting of errors is
intentional so the return value can be dropped to make gcc happy.

Also, fix typo in comment.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Return type of wait_for_completion_timeout() is unsigned long not int.
An appropriately named unsigned long is added and the assignment fixed.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

If a device is used as the root filesystem, it can't be built
off of devices which are within the root filesystem (just like
command line arguments to root=).  For this reason, Linux has a
pseudo-filesystem for root= and MD initialization (based on the
function name_to_dev_t) which handles different ways of specifying
devices including PARTUUID and major:minor.

Switch to using name_to_dev_t() in dm_get_device().  Rather than
having DM assume that all things which are not major:minor are paths in
an already-mounted filesystem, change dm_get_device() to first attempt
to look up the device in the filesystem, and if not found it will fall
back to using name_to_dev_t().

In terms of backwards compatibility, there are some cases where
behavior will be different:
- If you have a file in the current working directory named 1:2 and
  you initialze DM there, then it will try to use that file rather
  than the disk with that major:minor pair as a backing device.
- Similarly for other bdev types which name_to_dev_t() knows how to
  interpret, the previous behavior was to repeatedly check for the
  existence of the file (e.g., while waiting for rootfs to come up)
  but the new behavior is to use the name_to_dev_t() interpretation.
  For example, if you have a file named /dev/ubiblock0_0 which is
  a symlink to /dev/sda3, but it is not yet present when DM starts
  to initialize, then the name_to_dev_t() interpretation will take
  precedence.

These incompatibilities would only show up in really strange setups
with bad practices so we shouldn't have to worry about them.
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

In the kernel command-line, previously, root=1:2jakshflaksjdhfa would
be accepted and interpreted just like root=1:2. This patch adds
stricter checking so that additional characters after major:minor are
rejected by root=.

The goal of this change is to help in unifying DM's interpretation of
its block device argument by using existing kernel code (name_to_dev_t).
But DM rejects malformed major:minor pairs, it seems reasonable for
root= to reject them as well.
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

DM will switch its device lookup code to using name_to_dev_t() so it
must be exported.  Also, the @name argument should be marked const.
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Request-based DM's blk-mq support defaults to off; but a user can easily
change the default using the dm_mod.use_blk_mq module/boot option.

Also, you can check what mode a given request-based DM device is using
with: cat /sys/block/dm-X/dm/use_blk_mq

This change enabled further cleanup and reduced work (e.g. the
md->io_pool and md->rq_pool isn't created if using blk-mq).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

dm_mq_queue_rq() is in atomic context so care must be taken to not
sleep -- as such GFP_ATOMIC is used for the md->bs bioset allocations
and dm-mpath's call to blk_get_request().  In the future the bioset
allocations will hopefully go away (by removing support for partial
completions of bios in a cloned request).

Also prepare for supporting DM blk-mq ontop of old-style request_fn
device(s) if a new dm-mod 'use_blk_mq' parameter is set.  The kthread
will still be used to queue work if blk-mq is used ontop of old-style
request_fn device(s).
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Commit e5863d9a ("dm: allocate requests in target when stacking on
blk-mq devices") served as the first step toward fully utilizing blk-mq
in request-based DM -- it enabled stacking an old-style (request_fn)
request_queue ontop of the underlying blk-mq device(s).  That first step
didn't improve performance of DM multipath ontop of fast blk-mq devices
(e.g. NVMe) because the top-level old-style request_queue was severely
limited by the queue_lock.

The second step offered here enables stacking a blk-mq request_queue
ontop of the underlying blk-mq device(s).  This unlocks significant
performance gains on fast blk-mq devices, Keith Busch tested on his NVMe
testbed and offered this really positive news:

 "Just providing a performance update. All my fio tests are getting
  roughly equal performance whether accessed through the raw block
  device or the multipath device mapper (~470k IOPS). I could only push
  ~20% of the raw iops through dm before this conversion, so this latest
  tree is looking really solid from a performance standpoint."
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Tested-by: Keith Busch <keith.busch@intel.com>

Otherwise, for sequential workloads, the dm_request_fn can allow
excessive request merging at the expense of increased service time.

Add a per-device sysfs attribute to allow the user to control how long a
request, that is a reasonable merge candidate, can be queued on the
request queue.  The resolution of this request dispatch deadline is in
microseconds (ranging from 1 to 100000 usecs), to set a 20us deadline:
  echo 20 > /sys/block/dm-7/dm/rq_based_seq_io_merge_deadline

The dm_request_fn's merge heuristic and associated extra accounting is
disabled by default (rq_based_seq_io_merge_deadline is 0).

This sysfs attribute is not applicable to bio-based DM devices so it
will only ever report 0 for them.

By allowing a request to remain on the queue it will block others
requests on the queue.  But introducing a short dequeue delay has proven
very effective at enabling certain sequential IO workloads on really
fast, yet IOPS constrained, devices to build up slightly larger IOs --
yielding 90+% throughput improvements.  Having precise control over the
time taken to wait for larger requests to build affords control beyond
that of waiting for certain IO sizes to accumulate (which would require
a deadline anyway).  This knob will only ever make sense with sequential
IO workloads and the particular value used is storage configuration
specific.

Given the expected niche use-case for when this knob is useful it has
been deemed acceptable to expose this relatively crude method for
crafting optimal IO on specific storage -- especially given the solution
is simple yet effective.  In the context of DM multipath, it is
advisable to tune this sysfs attribute to a value that offers the best
performance for the common case (e.g. if 4 paths are expected active,
tune for that; if paths fail then performance may be slightly reduced).

Alternatives were explored to have request-based DM autotune this value
(e.g. if/when paths fail) but they were quickly deemed too fragile and
complex to warrant further design and development time.  If this problem
proves more common as faster storage emerges we'll have to look at
elevating a generic solution into the block core.
Tested-by: Shiva Krishna Merla <shivakrishna.merla@netapp.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Add DM_ATTR_RW() macro and establish .store method in dm_sysfs_ops.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Request-based DM's dm_request_fn() is so fast to pull requests off the
queue that steps need to be taken to promote merging by avoiding request
processing if it makes sense.

If the current request would've merged with previous request let the
current request stay on the queue longer.
Suggested-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Commit 7eaceacc ("block: remove per-queue plugging") didn't justify
DM's use of a 100ms delay; such an extended delay is a liability when
there is reason to re-kick the queue.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

In request-based DM's dm_request_fn(), if blk_peek_request() returns
NULL just return.  Avoids unnecessary blk_delay_queue().
Reported-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

On really fast storage it can be beneficial to delay running the
request_queue to allow the elevator more opportunity to merge requests.

Otherwise, it has been observed that requests are being sent to
q->request_fn much quicker than is ideal on IOPS-bound backends.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

The old dm_request() method used for q->make_request_fn had a branch for
request-based DM support but it isn't needed given that
dm_init_request_based_queue() sets it to the standard blk_queue_bio()
anyway.

Cleanup dm_init_md_queue() to be DM device-type agnostic and have
dm_setup_md_queue() properly finish queue setup based on DM device-type
(bio-based vs request-based).

A followup block patch can be made to remove the export for
blk_queue_bio() now that DM no longer calls it directly.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

DM multipath is the only caller of blk_lld_busy() -- which calls a
queue's lld_busy_fn hook.  Request-based DM doesn't support stacking
multipath devices so there is no reason to register the lld_busy_fn hook
on a multipath device's queue using blk_queue_lld_busy().

As such, remove functions dm_lld_busy and dm_table_any_busy_target.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

There is no need for DM to export a wrapper around the already exported
blk_lld_busy().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

__dm_get_module_param() could be useful for future DM module parameters
besides those related to "reserved_ios".
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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

Writeback takes out a lock on the cache block, so will increase the
latency for any concurrent io.

This patch works by placing 2 sentinel objects on each level of the
multiqueues.  Every WRITEBACK_PERIOD the oldest sentinel gets moved to
the newest end of the queue level.

When looking for writeback work:
  if less than 25% of the cache is clean:
    we select the oldest object with the lowest hit count
  otherwise:
    we select the oldest object that is not past a writeback sentinel.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Remove to stop wasting memory.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

A sentinel object is placed on each level of the multiqueues.  When an
object is hit it is requeued behind the sentinel.  When the tick is
incremented we iterate through all objects behind the sentinel and
update the hit_count, then reposition the sentinel at the very back.

This saves memory by avoiding tracking the tick explicitly for every
struct entry object in the multiqueues.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

queue_shift_down() didn't adjust the hit_counts to the new levels, so it
just had the effect of scrambling levels.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Small optimisation, now queue_empty() doesn't need to walk all levels of
the multiqueue.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

Use a single slab cache to allocate a mempool for each dirty-log.
This _should_ eliminate DM's need for io_schedule_timeout() in
mempool_alloc(); so io_schedule() should be sufficient now.

Also, rename struct flush_entry to dm_dirty_log_flush_entry to allow
KMEM_CACHE() to create a meaningful global name for the slab cache.

Also, eliminate some holes in struct log_c by rearranging members.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Heinz Mauelshagen <heinzm@redhat.com>

Linux 3.19 commit 69c953c8 ("lib/lcm.c: lcm(n,0)=lcm(0,n) is 0, not n")
caused blk_stack_limits() to not properly stack queue_limits for stacked
devices (e.g. DM).

Fix this regression by establishing lcm_not_zero() and switching
blk_stack_limits() over to using it.

DM uses blk_set_stacking_limits() to establish the initial top-level
queue_limits that are then built up based on underlying devices' limits
using blk_stack_limits().  In the case of optimal_io_size (io_opt)
blk_set_stacking_limits() establishes a default value of 0.  With commit
69c953c8, lcm(0, n) is no longer n, which compromises proper stacking of
the underlying devices' io_opt.

Test:
$ modprobe scsi_debug dev_size_mb=10 num_tgts=1 opt_blks=1536
$ cat /sys/block/sde/queue/optimal_io_size
786432
$ dmsetup create node --table "0 100 linear /dev/sde 0"

Before this fix:
$ cat /sys/block/dm-5/queue/optimal_io_size
0

After this fix:
$ cat /sys/block/dm-5/queue/optimal_io_size
786432
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.19+
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Don't assign ->rq_timeout twice.
Signed-off-by: Wei Fang <fangwei1@huawei.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

At the beginning of blk_mq_alloc_tag_set(), we have already checked whether
'set->nr_hw_queues' is zero, so here remove this redundant check.
Signed-off-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Pull ARM SoC fixes from Olof Johansson:
 "The latest and greatest fixes for ARM platform code.  Worth pointing
  out are:

   - Lines-wise, largest is a PXA fix for dealing with interrupts on DT
     that was quite broken.  It's still newish code so while we could
     have held this off, it seemed appropriate to include now

   - Some GPIO fixes for OMAP platforms added a few lines.  This was
     also fixes for code recently added (this release).

   - Small OMAP timer fix to behave better with partially upstreamed
     platforms, which is quite welcome.

   - Allwinner fixes about operating point control, reducing
     overclocking in some cases for better stability.

  plus a handful of other smaller fixes across the map"

* tag 'armsoc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  arm64: juno: Fix misleading name of UART reference clock
  ARM: dts: sunxi: Remove overclocked/overvoltaged OPP
  ARM: dts: sun4i: a10-lime: Override and remove 1008MHz OPP setting
  ARM: socfpga: dts: fix spi1 interrupt
  ARM: dts: Fix gpio interrupts for dm816x
  ARM: dts: dra7: remove ti,hwmod property from pcie phy
  ARM: OMAP: dmtimer: disable pm runtime on remove
  ARM: OMAP: dmtimer: check for pm_runtime_get_sync() failure
  ARM: OMAP2+: Fix socbus family info for AM33xx devices
  ARM: dts: omap3: Add missing dmas for crypto
  ARM: dts: rockchip: disable gmac by default in rk3288.dtsi
  MAINTAINERS: add rockchip regexp to the ARM/Rockchip entry
  ARM: pxa: fix pxa interrupts handling in DT
  ARM: pxa: Fix typo in zeus.c
  ARM: sunxi: Have ARCH_SUNXI select RESET_CONTROLLER for clock driver usage

Merge tag 'sunxi-fixes-for-4.0' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into fixes

Allwinner fixes for 4.0

There's a few fixes to merge for 4.0, one to add a select in the machine
Kconfig option to fix a potential build failure, and two fixing cpufreq related
issues.

* tag 'sunxi-fixes-for-4.0' of https://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
  ARM: dts: sunxi: Remove overclocked/overvoltaged OPP
  ARM: dts: sun4i: a10-lime: Override and remove 1008MHz OPP setting
  ARM: sunxi: Have ARCH_SUNXI select RESET_CONTROLLER for clock driver usage
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'fixes-v4.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes

Fixes for omaps for the -rc cycle:

- Fix a device tree based booting vs legacy booting regression for
  omap3 crypto hardware by adding the missing DMA channels.

- Fix /sys/bus/soc/devices/soc0/family for am33xx devices.

- Fix two timer issues that can cause hangs if the timer related
  hwmod data is missing like it often initially is for new SoCs.

- Remove pcie hwmods entry from dts as that causes runtime PM to
  fail for the PHYs.

- A paper bag type dts configuration fix for dm816x GPIO
  interrupts that I just noticed. This is most of the changes
  diffstat wise, but as it's a basic feature for connecting
  devices and things work otherwise, it should be fixed.

* tag 'fixes-v4.0-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  ARM: dts: Fix gpio interrupts for dm816x
  ARM: dts: dra7: remove ti,hwmod property from pcie phy
  ARM: OMAP: dmtimer: disable pm runtime on remove
  ARM: OMAP: dmtimer: check for pm_runtime_get_sync() failure
  ARM: OMAP2+: Fix socbus family info for AM33xx devices
  ARM: dts: omap3: Add missing dmas for crypto
Signed-off-by: Olof Johansson <olof@lixom.net>

Late fix for v4.0 on the SoCFPGA platform:
- Fix interrupt number for SPI1 interface

* tag 'socfpga_fix_for_v4.0_2' of git://git.rocketboards.org/linux-socfpga-next:
  ARM: socfpga: dts: fix spi1 interrupt
Signed-off-by: Olof Johansson <olof@lixom.net>

The UART reference clock speed is 7273.8 kHz, not 72738 kHz.

Dots aren't usually used in node names even though ePAPR permits
them.  However, this can easily be avoided by expressing the
frequency in Hz, not kHz.

This patch changes the name to refclk7273800hz, reflecting the
actual clock speed.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>