openwrt/staging/blogic.git
7 years agobcache: explicitly destroy mutex while exiting
Liang Chen [Mon, 30 Oct 2017 21:46:35 +0000 (14:46 -0700)]
bcache: explicitly destroy mutex while exiting

mutex_destroy does nothing most of time, but it's better to call
it to make the code future proof and it also has some meaning
for like mutex debug.

As Coly pointed out in a previous review, bcache_exit() may not be
able to handle all the references properly if userspace registers
cache and backing devices right before bch_debug_init runs and
bch_debug_init failes later. So not exposing userspace interface
until everything is ready to avoid that issue.

Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Reviewed-by: Eric Wheeler <bcache@linux.ewheeler.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: fix wrong cache_misses statistics
tang.junhui [Mon, 30 Oct 2017 21:46:34 +0000 (14:46 -0700)]
bcache: fix wrong cache_misses statistics

Currently, Cache missed IOs are identified by s->cache_miss, but actually,
there are many situations that missed IOs are not assigned a value for
s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO
(s->iop.bypass = 1), or the cache_bio allocate failed. In these situations,
it will go to out_put or out_submit, and s->cache_miss is null, which leads
bch_mark_cache_accounting() to treat this IO as a hit IO.

[ML: applied by 3-way merge]

Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: update bucket_in_use in real time
Tang Junhui [Mon, 30 Oct 2017 21:46:33 +0000 (14:46 -0700)]
bcache: update bucket_in_use in real time

bucket_in_use is updated in gc thread which triggered by invalidating or
writing sectors_to_gc dirty data, It's a long interval. Therefore, when we
use it to compare with the threshold, it is often not timely, which leads
to inaccurate judgment and often results in bucket depletion.

We have send a patch before, by the means of updating bucket_in_use
periodically In gc thread, which Coly thought that would lead high
latency, In this patch, we add avail_nbuckets to record the count of
available buckets, and we calculate bucket_in_use when alloc or free
bucket in real time.

[edited by ML: eliminated some whitespace errors]

Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: convert cached_dev.count from atomic_t to refcount_t
Elena Reshetova [Mon, 30 Oct 2017 21:46:32 +0000 (14:46 -0700)]
bcache: convert cached_dev.count from atomic_t to refcount_t

atomic_t variables are currently used to implement reference
counters with the following properties:
 - counter is initialized to 1 using atomic_set()
 - a resource is freed upon counter reaching zero
 - once counter reaches zero, its further
   increments aren't allowed
 - counter schema uses basic atomic operations
   (set, inc, inc_not_zero, dec_and_test, etc.)

Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.

The variable cached_dev.count is used as pure reference counter.
Convert it to refcount_t and fix up the operations.

Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: only permit to recovery read error when cache device is clean
Coly Li [Mon, 30 Oct 2017 21:46:31 +0000 (14:46 -0700)]
bcache: only permit to recovery read error when cache device is clean

When bcache does read I/Os, for example in writeback or writethrough mode,
if a read request on cache device is failed, bcache will try to recovery
the request by reading from cached device. If the data on cached device is
not synced with cache device, then requester will get a stale data.

For critical storage system like database, providing stale data from
recovery may result an application level data corruption, which is
unacceptible.

With this patch, for a failed read request in writeback or writethrough
mode, recovery a recoverable read request only happens when cache device
is clean. That is to say, all data on cached device is up to update.

For other cache modes in bcache, read request will never hit
cached_dev_read_error(), they don't need this patch.

Please note, because cache mode can be switched arbitrarily in run time, a
writethrough mode might be switched from a writeback mode. Therefore
checking dc->has_data in writethrough mode still makes sense.

Changelog:
V4: Fix parens error pointed by Michael Lyle.
v3: By response from Kent Oversteet, he thinks recovering stale data is a
    bug to fix, and option to permit it is unnecessary. So this version
    the sysfs file is removed.
v2: rename sysfs entry from allow_stale_data_on_failure  to
    allow_stale_data_on_failure, and fix the confusing commit log.
v1: initial patch posted.

[small change to patch comment spelling by mlyle]

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reported-by: Arne Wolf <awolf@lenovo.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Nix <nix@esperi.org.uk>
Cc: Kai Krakow <hurikhan77@gmail.com>
Cc: Eric Wheeler <bcache@lists.ewheeler.net>
Cc: Junhui Tang <tang.junhui@zte.com.cn>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: Fix a race between blk_cleanup_queue() and timeout handling
Bart Van Assche [Thu, 19 Oct 2017 17:00:48 +0000 (10:00 -0700)]
block: Fix a race between blk_cleanup_queue() and timeout handling

Make sure that if the timeout timer fires after a queue has been
marked "dying" that the affected requests are finished.

Reported-by: chenxiang (M) <chenxiang66@hisilicon.com>
Fixes: commit 287922eb0b18 ("block: defer timeouts to a workqueue")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Tested-by: chenxiang (M) <chenxiang66@hisilicon.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agomq-deadline: add 'deadline' as a name alias
Jens Axboe [Wed, 25 Oct 2017 15:47:20 +0000 (09:47 -0600)]
mq-deadline: add 'deadline' as a name alias

The scheduler framework now supports looking up the appropriate
scheduler with the {name,mq} tupple. We can register mq-deadline
with the alias of 'deadline', so that switching to 'deadline'
will do the right thing based on the type of driver attached to
it.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoelevator: allow name aliases
Jens Axboe [Wed, 25 Oct 2017 18:35:02 +0000 (12:35 -0600)]
elevator: allow name aliases

Since we now lookup elevator types with the appropriate multiqueue
capability, allow schedulers to register with an alias alongside
the real name. This is in preparation for allowing 'mq-deadline'
to register an alias of 'deadline' as well.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoelevator: lookup mq vs non-mq elevators
Jens Axboe [Wed, 25 Oct 2017 18:33:42 +0000 (12:33 -0600)]
elevator: lookup mq vs non-mq elevators

If an IO scheduler is selected via elevator= and it doesn't match
the driver in question wrt blk-mq support, then we fail to boot.

The elevator= parameter is deprecated and only supported for
non-mq devices. Augment the elevator lookup API so that we
pass in if we're looking for an mq capable scheduler or not,
so that we only ever return a valid type for the queue in
question.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196695
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: cope with WRITE ZEROES failing in blkdev_issue_zeroout()
Ilya Dryomov [Mon, 16 Oct 2017 13:59:10 +0000 (15:59 +0200)]
block: cope with WRITE ZEROES failing in blkdev_issue_zeroout()

sd_config_write_same() ignores ->max_ws_blocks == 0 and resets it to
permit trying WRITE SAME on older SCSI devices, unless ->no_write_same
is set.  Because REQ_OP_WRITE_ZEROES is implemented in terms of WRITE
SAME, blkdev_issue_zeroout() may fail with -EREMOTEIO:

  $ fallocate -zn -l 1k /dev/sdg
  fallocate: fallocate failed: Remote I/O error
  $ fallocate -zn -l 1k /dev/sdg  # OK
  $ fallocate -zn -l 1k /dev/sdg  # OK

The following calls succeed because sd_done() sets ->no_write_same in
response to a sense that would become BLK_STS_TARGET/-EREMOTEIO, causing
__blkdev_issue_zeroout() to fall back to generating ZERO_PAGE bios.

This means blkdev_issue_zeroout() must cope with WRITE ZEROES failing
and fall back to manually zeroing, unless BLKDEV_ZERO_NOFALLBACK is
specified.  For BLKDEV_ZERO_NOFALLBACK case, return -EOPNOTSUPP if
sd_done() has just set ->no_write_same thus indicating lack of offload
support.

Fixes: c20cfc27a473 ("block: stop using blkdev_issue_write_same for zeroing")
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: factor out __blkdev_issue_zero_pages()
Ilya Dryomov [Mon, 16 Oct 2017 13:59:09 +0000 (15:59 +0200)]
block: factor out __blkdev_issue_zero_pages()

blkdev_issue_zeroout() will use this in !BLKDEV_ZERO_NOFALLBACK case.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: move CAP_SYS_ADMIN check in blkdev_roset()
Ilya Dryomov [Wed, 18 Oct 2017 12:38:38 +0000 (14:38 +0200)]
block: move CAP_SYS_ADMIN check in blkdev_roset()

Check for CAP_SYS_ADMIN before calling into the driver, similar to
blkdev_flushbuf().  This is safer and can spare a check in the driver.

(Currently BLKROSET is overridden by md and rbd, rbd is missing the
check.  md has the check, but it covers a lot more than BLKROSET.)

Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: Invalidate cache on discard v2
Dmitry Monakhov [Wed, 25 Oct 2017 00:44:57 +0000 (18:44 -0600)]
block: Invalidate cache on discard v2

It is reasonable drop page cache on discard, otherwise that pages may
be written by writeback second later, so thin provision devices will
not be happy. This seems to be a  security leak in case of secure discard case.

Also add check for queue_discard flag on early stage.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: remove leftover testing function
Javier González [Tue, 24 Oct 2017 13:56:13 +0000 (15:56 +0200)]
lightnvm: pblk: remove leftover testing function

A previous patch inadvertently left an unused test function in the
header, kill it.

Fixes: 8bd400204bd5 ("lightnvm: pblk: cleanup unused and static functions")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agokyber: fix hang on domain token wait queue
Omar Sandoval [Wed, 11 Oct 2017 17:39:15 +0000 (10:39 -0700)]
kyber: fix hang on domain token wait queue

When we're getting a domain token, if we fail to get a token on our
first attempt, we put the current hardware queue on a wait queue and
then try again just in case a token was freed after our initial attempt
but before we got on the wait queue. If this second attempt succeeds, we
currently leave the hardware queue on the wait queue. Usually this is
okay; we'll just run the hardware queue one extra time when another
token is freed. However, if the hardware queue doesn't have any other
requests waiting, then when it it gets the extra wakeup, it won't have
anything to free and therefore won't wake up any other hardware queues.
If tokens are limited, then we won't make forward progress and the
device will hang.

Reported-by: Bin Zha <zhabin.zb@alibaba-inc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agonullb: fix error return code in null_init()
Wei Yongjun [Tue, 17 Oct 2017 12:11:46 +0000 (12:11 +0000)]
nullb: fix error return code in null_init()

Fix to return error code -ENOMEM from the null_alloc_dev() error
handling case instead of 0, as done elsewhere in this function.

Fixes: 2984c8684f96 ("nullb: factor disk parameters")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: fix Sphinx kernel-doc warning
Randy Dunlap [Mon, 16 Oct 2017 18:01:00 +0000 (11:01 -0700)]
block: fix Sphinx kernel-doc warning

Sphinx treats symbols that end with '_' as a kind of special
documentation indicator, so fix that by adding an ending '*'
to it.

../block/bio.c:404: ERROR: Unknown target name: "gfp".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: writeback rate clamping: make 32 bit safe
Michael Lyle [Mon, 16 Oct 2017 17:34:47 +0000 (10:34 -0700)]
bcache: writeback rate clamping: make 32 bit safe

Sorry this got through to linux-block, was detected by the kbuilds test
robot.  NSEC_PER_SEC is a long constant; 2.5 * 10^9 doesn't fit in a
signed long constant.

Fixes: e41166c5c44e ("bcache: writeback rate shouldn't artifically clamp")
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: MAINTAINERS: set bcache to MAINTAINED
Michael Lyle [Fri, 13 Oct 2017 23:35:42 +0000 (16:35 -0700)]
bcache: MAINTAINERS: set bcache to MAINTAINED

Also add URL for IRC channel.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: Add Michael Lyle to MAINTAINERS
Kent Overstreet [Fri, 13 Oct 2017 23:35:41 +0000 (16:35 -0700)]
bcache: Add Michael Lyle to MAINTAINERS

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: safeguard a dangerous addressing in closure_queue
Liang Chen [Fri, 13 Oct 2017 23:35:40 +0000 (16:35 -0700)]
bcache: safeguard a dangerous addressing in closure_queue

The use of the union reduces the size of closure struct by taking advantage
of the current size of its members. The offset of func in work_struct
equals the size of the first three members, so that work.work_func will
just reference the forth member - fn.

This is smart but dangerous. It can be broken if work_struct or the other
structs get changed, and can be a bit difficult to debug.

Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: rearrange writeback main thread ratelimit
Michael Lyle [Fri, 13 Oct 2017 23:35:39 +0000 (16:35 -0700)]
bcache: rearrange writeback main thread ratelimit

The time spent searching for things to write back "counts" for the
actual rate achieved, so don't flush the accumulated rate with each
chunk.

This will maintain better fidelity to user-commanded rates, but it
may slightly increase the burstiness of writeback.  The writeback
lock needs improvement to help mitigate this.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: writeback rate shouldn't artifically clamp
Michael Lyle [Fri, 13 Oct 2017 23:35:38 +0000 (16:35 -0700)]
bcache: writeback rate shouldn't artifically clamp

The previous code artificially limited writeback rate to 1000000
blocks/second (NSEC_PER_MSEC), which is a rate that can be met on fast
hardware.  The rate limiting code works fine (though with decreased
precision) up to 3 orders of magnitude faster, so use NSEC_PER_SEC.

Additionally, ensure that uint32_t is used as a type for rate throughout
the rate management so that type checking/clamp_t can work properly.

bch_next_delay should be rewritten for increased precision and better
handling of high rates and long sleep periods, but this is adequate for
now.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reported-by: Coly Li <colyli@suse.de>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: smooth writeback rate control
Michael Lyle [Fri, 13 Oct 2017 23:35:37 +0000 (16:35 -0700)]
bcache: smooth writeback rate control

This works in conjunction with the new PI controller.  Currently, in
real-world workloads, the rate controller attempts to write back 1
sector per second.  In practice, these minimum-rate writebacks are
between 4k and 60k in test scenarios, since bcache aggregates and
attempts to do contiguous writes and because filesystems on top of
bcachefs typically write 4k or more.

Previously, bcache used to guarantee to write at least once per second.
This means that the actual writeback rate would exceed the configured
amount by a factor of 8-120 or more.

This patch adjusts to be willing to sleep up to 2.5 seconds, and to
target writing 4k/second.  On the smallest writes, it will sleep 1
second like before, but many times it will sleep longer and load the
backing device less.  This keeps the loading on the cache and backing
device related to writeback more consistent when writing back at low
rates.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: implement PI controller for writeback rate
Michael Lyle [Fri, 13 Oct 2017 23:35:36 +0000 (16:35 -0700)]
bcache: implement PI controller for writeback rate

bcache uses a control system to attempt to keep the amount of dirty data
in cache at a user-configured level, while not responding excessively to
transients and variations in write rate.  Previously, the system was a
PD controller; but the output from it was integrated, turning the
Proportional term into an Integral term, and turning the Derivative term
into a crude Proportional term.  Performance of the controller has been
uneven in production, and it has tended to respond slowly, oscillate,
and overshoot.

This patch set replaces the current control system with an explicit PI
controller and tuning that should be correct for most hardware.  By
default, it attempts to write at a rate that would retire 1/40th of the
current excess blocks per second.  An integral term in turn works to
remove steady state errors.

IMO, this yields benefits in simplicity (removing weighted average
filtering, etc) and system performance.

Another small change is a tunable parameter is introduced to allow the
user to specify a minimum rate at which dirty blocks are retired.

There is a slight difference from earlier versions of the patch in
integral handling to prevent excessive negative integral windup.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: don't write back data if reading it failed
Michael Lyle [Fri, 13 Oct 2017 23:35:35 +0000 (16:35 -0700)]
bcache: don't write back data if reading it failed

If an IO operation fails, and we didn't successfully read data from the
cache, don't writeback invalid/partial data to the backing disk.

Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: remove unused parameter
Yijing Wang [Fri, 13 Oct 2017 23:35:34 +0000 (16:35 -0700)]
bcache: remove unused parameter

Parameter bio is no longer used, clean it.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: update bio->bi_opf bypass/writeback REQ_ flag hints
Eric Wheeler [Fri, 13 Oct 2017 23:35:33 +0000 (16:35 -0700)]
bcache: update bio->bi_opf bypass/writeback REQ_ flag hints

Flag for bypass if the IO is for read-ahead or background, unless the
read-ahead request is for metadata (eg, from gfs2).
        Bypass if:
                bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) &&
!(bio->bi_opf & REQ_META))

        Writeback if:
                op_is_sync(bio->bi_opf) ||
bio->bi_opf & (REQ_META|REQ_PRIO)

Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: Remove redundant set_capacity
Yijing Wang [Fri, 13 Oct 2017 23:35:32 +0000 (16:35 -0700)]
bcache: Remove redundant set_capacity

set_capacity() has been called in bcache_device_init(),
remove the redundant one.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Reviewed-by: Eric Wheeler <bcache@linux.ewheeler.net>
Acked-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: rewrite multiple partitions support
Coly Li [Fri, 13 Oct 2017 23:35:31 +0000 (16:35 -0700)]
bcache: rewrite multiple partitions support

Current partition support of bcache is confusing and buggy. It tries to
trace non-continuous device minor numbers by an ida bit string, and
mistakenly mixed bcache device index with minor numbers. This design
generates several negative results,
- Index of bcache device name is not consecutive under /dev/. If there are
  3 bcache devices, they name will be,
  /dev/bcache0, /dev/bcache16, /dev/bcache32
  Only bcache code indexes bcache device name is such an interesting way.
- First minor number of each bcache device is traced by ida bit string.
  One bcache device will occupy 16 bits, this is not a good idea. Indeed
  only one bit is enough.
- Because minor number and bcache device index are mixed, a device index
  is allocated by ida_simple_get(), but an first minor number is sent into
  ida_simple_remove() to release the device. It confused original author
  too.

Root cause of the above errors is, bcache code should not handle device
minor numbers at all! A standard process to support multiple partitions in
Linux kernel is,
- Device driver provides major device number, and indexes multiple device
  instances.
- Device driver does not allocat nor trace device minor number, only
  provides a first minor number of a given device instance, and sets how
  many minor numbers (paritions) the device instance may have.
All rested stuffs are handled by block layer code, most of the details can
be found from block/{genhd, partition-generic}.c files.

This patch re-writes multiple partitions support for bcache. It makes
whole things to be more clear, and uses ida bit string in a more efficeint
way.
- Ida bit string only traces bcache device index, not minor number. For a
  bcache device with 128 partitions, only one bit in ida bit string is
  enough.
- Device minor number and device index are separated in concept. Device
  index is used for /dev node naming, and ida bit string trace. Minor
  number is calculated from device index and only used to initialize
  first_minor of a bcache device.
- It does not follow any standard for 16 partitions on a bcache device.
  This patch sets 128 partitions on single bcache device at max, this is
  the limitation from GPT (GUID Partition Table) and supported by fdisk.

Considering a typical device minor number is 20 bits width, each bcache
device may have 128 partitions (7 bits), there can be 8192 bcache devices
existing on system. For most common deployment for a single server in
now days, it should be enough.

[minor spelling fixes in commit message by Michael Lyle]

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Eric Wheeler <bcache@lists.ewheeler.net>
Cc: Junhui Tang <tang.junhui@zte.com.cn>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: fix a comments typo in bch_alloc_sectors()
Coly Li [Fri, 13 Oct 2017 23:35:30 +0000 (16:35 -0700)]
bcache: fix a comments typo in bch_alloc_sectors()

Code comments in alloc.c:bch_alloc_sectors() mentions a function
name find_data_bucket(), the correct function name should be
pick_data_bucket() indeed. bch_alloc_sectors() is a quite important
function in bcache allocation code, fixing the typo may help
other people to have less confusion.

Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Tang Junhui <tang.junhui@zte.com.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: check ca->alloc_thread initialized before wake up it
Coly Li [Fri, 13 Oct 2017 23:35:29 +0000 (16:35 -0700)]
bcache: check ca->alloc_thread initialized before wake up it

In bcache code, sysfs entries are created before all resources get
allocated, e.g. allocation thread of a cache set.

There is posibility for NULL pointer deference if a resource is accessed
but which is not initialized yet. Indeed Jorg Bornschein catches one on
cache set allocation thread and gets a kernel oops.

The reason for this bug is, when bch_bucket_alloc() is called during
cache set registration and attaching, ca->alloc_thread is not properly
allocated and initialized yet, call wake_up_process() on ca->alloc_thread
triggers NULL pointer deference failure. A simple and fast fix is, before
waking up ca->alloc_thread, checking whether it is allocated, and only
wake up ca->alloc_thread when it is not NULL.

Signed-off-by: Coly Li <colyli@suse.de>
Reported-by: Jorg Bornschein <jb@capsec.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agobcache: Avoid nested function definition
Peter Foley [Fri, 13 Oct 2017 23:35:28 +0000 (16:35 -0700)]
bcache: Avoid nested function definition

Fixes below error with clang:
../drivers/md/bcache/sysfs.c:759:3: error: function definition is not allowed here
                {       return *((uint16_t *) r) - *((uint16_t *) l); }
                ^
../drivers/md/bcache/sysfs.c:789:32: error: use of undeclared identifier 'cmp'
                sort(p, n, sizeof(uint16_t), cmp, NULL);
                                             ^
2 errors generated.

v2:
rename function to __bch_cache_cmp

Signed-off-by: Peter Foley <pefoley2@pefoley.com>
Reviewed-by: Coly Li <colyli@suse.de>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agomm/page-writeback.c: make changes of dirty_writeback_centisecs take effect immediately
Yafang Shao [Sat, 14 Oct 2017 08:38:27 +0000 (16:38 +0800)]
mm/page-writeback.c: make changes of dirty_writeback_centisecs take effect immediately

This patch is the followup of the prvious patch:
[writeback: schedule periodic writeback with sysctl].

There's another issue to fix.
For example,
- When the tunable was set to one hour and is reset to one second, the
  new setting will not take effect for up to one hour.

Kicking the flusher threads immediately fixes it.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agonull_blk: add usage hints for no_sched
weiping zhang [Fri, 13 Oct 2017 16:26:54 +0000 (00:26 +0800)]
null_blk: add usage hints for no_sched

This parameter provide an option to disable io scheduler when nullb*
in multi-queue mode.

Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agonull_blk: update usage hints for submit_queues
weiping zhang [Fri, 13 Oct 2017 16:26:28 +0000 (00:26 +0800)]
null_blk: update usage hints for submit_queues

update the range of submits_queues, and correct usage hints.

Signed-off-by: weiping zhang <zhangweiping@didichuxing.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoRevert "lightnvm: prevent bd removal if busy"
Jens Axboe [Fri, 13 Oct 2017 15:36:06 +0000 (09:36 -0600)]
Revert "lightnvm: prevent bd removal if busy"

Christoph correctly points out that this issue is no different
for other block devices, and poking at cross layer internals
is not the right way to solve it.

This reverts commit bb6aa6f08268bbce4e0185b18cab9e04505d6695.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: implement generic path for sync I/O
Javier González [Fri, 13 Oct 2017 12:46:47 +0000 (14:46 +0200)]
lightnvm: implement generic path for sync I/O

Implement a generic path for sending sync I/O on LightNVM. This allows
to reuse the standard synchronous path trough blk_execute_rq(), instead
of implementing a wait_for_completion on the target side (e.g., pblk).

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: fail fast on passthrough commands
Javier González [Fri, 13 Oct 2017 12:46:46 +0000 (14:46 +0200)]
lightnvm: fail fast on passthrough commands

Make LightNVM passhtrough commands fail fast. User space will then take
care of re-submitting.

Fixes: 84d4add793c6 ('lightnvm: add ioctls for vector I/Os')
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: avoid being reported as hung on rated GC
Javier González [Fri, 13 Oct 2017 12:46:45 +0000 (14:46 +0200)]
lightnvm: pblk: avoid being reported as hung on rated GC

The amount of GC I/O on the write buffer is managed by the rate-limiter,
which is calculated as a function of the number of available free
blocks. When reaching the stable point, we risk having scheduled more
I/Os for GC than are allowed on the write buffer. This would result on
the GC semaphore balancing the outstanding read GC I/Os to be reported
as "hung", though the behavior is normal.

Solve this by allowing to schedule when we detect that the read GC path
is not moving forward.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: cleanup unused and static functions
Javier González [Fri, 13 Oct 2017 12:46:44 +0000 (14:46 +0200)]
lightnvm: pblk: cleanup unused and static functions

Cleanup up unused and static functions across the whole codebase.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: remove spinlock when freeing line metadata
Hans Holmberg [Fri, 13 Oct 2017 12:46:43 +0000 (14:46 +0200)]
lightnvm: pblk: remove spinlock when freeing line metadata

Lockdep complains about being in atomic context while freeing line
metadata - and rightly so as we take a spinlock and end up calling
vfree that might sleep(in pblk_mfree).

There is no need for holding the line manager free_lock while
freeing line metadata as the pipeline as stopped, so remove the lock.

Fixes: 588726d3ec68 ("lightnvm: pblk: fail gracefully on irrec. error")
Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: correct valid lba count calculation
Hans Holmberg [Fri, 13 Oct 2017 12:46:42 +0000 (14:46 +0200)]
lightnvm: pblk: correct valid lba count calculation

During garbage collect, lbas being written can end up
being invalidated. Make sure that this is reflected in
the valid lba count.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: gc all lines in the pipeline before exit
Hans Holmberg [Fri, 13 Oct 2017 12:46:41 +0000 (14:46 +0200)]
lightnvm: pblk: gc all lines in the pipeline before exit

Finish garbage collect of the lines that are in the gc pipeline
before exiting. Ensure that all lines already in in the pipeline
goes through, from read to write.

Do this by keeping track of how many lines are in the pipeline
and waiting for that number to reach zero before exiting the gc
reader task.

Since we're adding a new gc line counter, change the name of
inflight_gc to read_inflight_gc to make the distinction clear.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: add l2p crc debug printouts
Hans Holmberg [Fri, 13 Oct 2017 12:46:40 +0000 (14:46 +0200)]
lightnvm: pblk: add l2p crc debug printouts

Print the CRC of the logical-to-physical mapping during exit and
after recovering the L2P table to facilitate detection of meta
data corruption/recovery issues.

The CRC printed after recovery should match the CRC printed during
the previous exit - if it doesn't this indicates that either the meta
data written to the disk is corrupt or recovery failed.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: shut down gc gracefully during exit
Hans Holmberg [Fri, 13 Oct 2017 12:46:39 +0000 (14:46 +0200)]
lightnvm: pblk: shut down gc gracefully during exit

Shut down the GC workqueues and tasks in the right order.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: consider bad sectors in emeta during recovery
Hans Holmberg [Fri, 13 Oct 2017 12:46:38 +0000 (14:46 +0200)]
lightnvm: pblk: consider bad sectors in emeta during recovery

When recovering lines we need to consider that bad blocks in a line
affect the emeta area size.

Previously it was assumed that the emeta area would grow by the
number of sectors per page * number of bad blocks in the line.

This assumption is not correct - the number of "extra" pages that are
consumed could be both smaller (depending on emeta size) and bigger
(depending on the placement of the bad blocks).

Fix this by calculating the emeta start by iterating backwards
through the line, skipping ppas that map to bad blocks.

Also fix the data types used for ppa indices/counts in
pblk_recov_l2p_from_emeta - we should use u64.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: start gc if needed during init
Hans Holmberg [Fri, 13 Oct 2017 12:46:37 +0000 (14:46 +0200)]
lightnvm: pblk: start gc if needed during init

Start GC if needed, directly after init, as we might
need to garbage collect in order to make room for user writes.

Create a helper function that allows to kick GC without exposing the
internals of the GC/rate-limiter interaction.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: free full lines during recovery
Hans Holmberg [Fri, 13 Oct 2017 12:46:36 +0000 (14:46 +0200)]
lightnvm: pblk: free full lines during recovery

When rebuilding the L2P table, any full lines (lines without any
valid sectors) will be identified. If these lines are not freed,
we risk not being able to allocate the first data line.

This patch refactors the part of GC that frees empty lines
into a separate function and adds a call to this after the
L2P table has been rebuilt.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: recover partially written lines correctly
Hans Holmberg [Fri, 13 Oct 2017 12:46:35 +0000 (14:46 +0200)]
lightnvm: pblk: recover partially written lines correctly

When recovering partially written lines, the valid sector
count must be decreased by the number of padded sectors
in the line.

Update line recovery to take all ADDR_EMPTY(padded) sectors
into account.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: prevent gc kicks when gc is not operational
Hans Holmberg [Fri, 13 Oct 2017 12:46:34 +0000 (14:46 +0200)]
lightnvm: pblk: prevent gc kicks when gc is not operational

GC can be kicked after it has been shut down when closing the last
line during exit, resulting in accesses to freed structures.

Make sure that GC is not triggered while it is not operational.
Also make sure that GC won't be re-activated during exit when
running on another processor by using timer_del_sync.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: fix releases of kmem cache in error path
Rakesh Pandit [Fri, 13 Oct 2017 12:46:33 +0000 (14:46 +0200)]
lightnvm: pblk: fix releases of kmem cache in error path

If pblk_core_init fails lets destroy all global caches.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: reduce arguments in __pblk_rb_update_l2p
Rakesh Pandit [Fri, 13 Oct 2017 12:46:32 +0000 (14:46 +0200)]
lightnvm: pblk: reduce arguments in __pblk_rb_update_l2p

We already pass the structure pointer so no need to pass the member.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: remove stale extern and unused exported symbols
Rakesh Pandit [Fri, 13 Oct 2017 12:46:31 +0000 (14:46 +0200)]
lightnvm: remove stale extern and unused exported symbols

Not all exported symbols are being used outside core and there were
some stale entries in lightnvm.h

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: remove unused argument from nvm_set_tgt_bb_tbl
Rakesh Pandit [Fri, 13 Oct 2017 12:46:30 +0000 (14:46 +0200)]
lightnvm: remove unused argument from nvm_set_tgt_bb_tbl

vblk isn't being used anyway and if we ever have a usecase we can
introduce this again.  This makes the logic easier and removes
unnecessary checks.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: remove useless line
Rakesh Pandit [Fri, 13 Oct 2017 12:46:29 +0000 (14:46 +0200)]
lightnvm: pblk: remove useless line

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: fix changing GC group list for a line
Rakesh Pandit [Fri, 13 Oct 2017 12:46:28 +0000 (14:46 +0200)]
lightnvm: pblk: fix changing GC group list for a line

pblk_line_gc_list seems to had a bug since the introduction of pblk in
getting GC list for a line. In b20ba1bc7 while redesigning the GC
algorithm, the naming for the GC thresholds was altered, but the
values for high_thrs and mid_thrs were not. The result is that when
moving to the GC lists, the mid threshold is never evaluated.

Fixes: a4bd217b4("lightnvm: physical block device (pblk) target")
Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: ensure right bad block calculation
Javier González [Fri, 13 Oct 2017 12:46:27 +0000 (14:46 +0200)]
lightnvm: pblk: ensure right bad block calculation

Make sure that the variable controlling block threshold for allocating
extra metadata sectors in case of a line with bad blocks does not get a
negative value. Otherwise, the line will be marked as corrupted and
wasted.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: enable 1 LUN configuration
Javier González [Fri, 13 Oct 2017 12:46:26 +0000 (14:46 +0200)]
lightnvm: pblk: enable 1 LUN configuration

Metadata I/Os are scheduled to minimize their impact on user data I/Os.
When there are enough LUNs instantiated (i.e., enough bandwidth), it is
easy to interleave metadata and data one after the other so that
metadata I/Os are the ones being blocked and not vice-versa.

We do this by calculating the distance between the I/Os in terms of the
LUNs that are not in used, and selecting a free LUN that satisfies a
the simple heuristic that metadata is scheduled behind. The per-LUN
semaphores guarantee consistency. This works fine on >1 LUN
configuration. However, when a single LUN is instantiated, this design
leads to a deadlock, where metadata waits to be scheduled on a free LUN.

This patch implements the 1 LUN case by simply scheduling the metadada
I/O after the data I/O. In the process, we refactor the way a line is
replaced to ensure that metadata writes are submitted after data writes
in order to guarantee block sequentiality. Note that, since there is
only one LUN, both I/Os will block each other by design. However, such
configuration only pursues tight read latencies, not write bandwidth.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: remove I/O dependency on write path
Javier González [Fri, 13 Oct 2017 12:46:25 +0000 (14:46 +0200)]
lightnvm: pblk: remove I/O dependency on write path

pblk schedules user I/O, metadata I/O and erases on the write path in
order to minimize collisions at the media level. Until now, there has
been a dependency between user and metadata I/Os that could lead to a
deadlock as both take the per-LUN semaphore to schedule submission.

This path removes this dependency and guarantees forward progress at a
per I/O granurality.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: remove redundant check on read path
Javier González [Fri, 13 Oct 2017 12:46:24 +0000 (14:46 +0200)]
lightnvm: pblk: remove redundant check on read path

A partial read I/O in pblk is an I/O where some sectors reside in the
write buffer in main memory and some are persisted on the device. Such
an I/O must at least contain 2 lbas, therefore checking for the case
where a single lba is mapped is not necessary.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: guarantee line integrity on reads
Javier González [Fri, 13 Oct 2017 12:46:23 +0000 (14:46 +0200)]
lightnvm: pblk: guarantee line integrity on reads

When a line is recycled during garbage collection, reads can still be
issued to the line. If the line is freed in the middle of this process,
data corruption might occur.

This patch guarantees that lines are not freed in the middle of reads
that target them (lines). Specifically, we use the existing line
reference to decide when a line is eligible for being freed after the
recycle process.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: check lba sanity on read path
Javier González [Fri, 13 Oct 2017 12:46:22 +0000 (14:46 +0200)]
lightnvm: pblk: check lba sanity on read path

As part of pblk's recovery scheme, we store the lba mapped to each
physical sector on the device's out-of-bound (OOB) area.

On the read path, we can use this information to validate that the data
being delivered to the upper layers corresponds to the lba being
requested. The cost of this check is an extra copy on the DMA region on
the device and an extra comparison in the host, given that (i) the OOB
area is being read together with the data in the media, and (ii) the DMA
region allocated for the ppa list can be reused for the metadata stored
on the OOB area.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: use rqd->end_io for completion
Javier González [Fri, 13 Oct 2017 12:46:21 +0000 (14:46 +0200)]
lightnvm: pblk: use rqd->end_io for completion

For consistency with the rest of pblk, use rqd->end_io to point to the
function taking care of ending the request on the completion path.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: refactor rqd alloc/free
Javier González [Fri, 13 Oct 2017 12:46:20 +0000 (14:46 +0200)]
lightnvm: pblk: refactor rqd alloc/free

Refactor the rqd allocation and free functions so that all I/O types can
use these helper functions.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: improve naming for internal req.
Javier González [Fri, 13 Oct 2017 12:46:19 +0000 (14:46 +0200)]
lightnvm: pblk: improve naming for internal req.

Each request type sent to the LightNVM subsystem requires different
metadata. Until now, we have tailored this metadata based on write, read
and erase commands. However, pblk uses different metadata for internal
writes that do not hit the write buffer. Instead of abusing the metadata
for reads, create a new request type - internal write to improve
code readability.

In the process, create internal values for each I/O type instead of
abusing the READ/WRITE macros, as suggested by Christoph.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: allocate bio size more accurately
Javier González [Fri, 13 Oct 2017 12:46:18 +0000 (14:46 +0200)]
lightnvm: pblk: allocate bio size more accurately

Wait until we know the exact number of ppas to be sent to the device,
before allocating the bio.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: simplify path on REQ_PREFLUSH
Javier González [Fri, 13 Oct 2017 12:46:17 +0000 (14:46 +0200)]
lightnvm: pblk: simplify path on REQ_PREFLUSH

On REQ_PREFLUSH, directly tag the I/O context flags to signal a flush in
the write to cache path, instead of finding the correct entry context
and imposing a memory barrier. This simplifies the code and might
potentially prevent race conditions when adding functionality to the
write path.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: put bio on bio completion
Javier González [Fri, 13 Oct 2017 12:46:16 +0000 (14:46 +0200)]
lightnvm: pblk: put bio on bio completion

Simplify put bio by doing it on bio end_io instead of manually putting
it on the completion path.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: refactor read path on GC
Javier González [Fri, 13 Oct 2017 12:46:15 +0000 (14:46 +0200)]
lightnvm: pblk: refactor read path on GC

Simplify the part of the garbage collector where data is read from the
line being recycled and moved into an internal queue before being copied
to the memory buffer. This allows to get rid of a dedicated function,
which introduces an unnecessary dependency on the code.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: simplify data validity check on GC
Javier González [Fri, 13 Oct 2017 12:46:14 +0000 (14:46 +0200)]
lightnvm: pblk: simplify data validity check on GC

When a line is selected for recycling by the garbage collector (GC), the
line state changes and the invalid bitmap is frozen, preventing
invalidations from happening. Throughout the GC, the L2P map is checked
to verify that not data being recycled has been updated. The last check
is done before the new map is being stored on the L2P table. Though
this algorithm works, it requires a number of corner cases to be checked
each time the L2P table is being updated. This complicates readability
and is error prone in case that the recycling algorithm is modified.

Instead, this patch makes the invalid bitmap accessible even when the
line is being recycled. When recycled data is being remapped, it is
enough to check the invalid bitmap for the line before updating the L2P
table.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: refactor read lba sanity check
Javier González [Fri, 13 Oct 2017 12:46:13 +0000 (14:46 +0200)]
lightnvm: pblk: refactor read lba sanity check

Refactor lba sanity check on read path to avoid code duplication.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: normalize ppa namings
Javier González [Fri, 13 Oct 2017 12:46:12 +0000 (14:46 +0200)]
lightnvm: pblk: normalize ppa namings

Normalize the way we name ppa variables to improve code readability.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: use constant for GC max inflight
Javier González [Fri, 13 Oct 2017 12:46:11 +0000 (14:46 +0200)]
lightnvm: pblk: use constant for GC max inflight

Use a constant to set the maximum number of inflight GC requests
allowed.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: remove checks on mempool alloc.
Javier González [Fri, 13 Oct 2017 12:46:10 +0000 (14:46 +0200)]
lightnvm: pblk: remove checks on mempool alloc.

As part of the mempool audit on pblk, remove unnecessary mempool
allocation checks on mempools.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: do not use a mempool for line bitmaps
Javier González [Fri, 13 Oct 2017 12:46:09 +0000 (14:46 +0200)]
lightnvm: pblk: do not use a mempool for line bitmaps

pblk holds two sector bitmaps: one to keep track of the mapped sectors
while the line is active and another one to keep track of the invalid
sectors. The latter is kept during the whole live of the line, until it
is recycled. Since we cannot guarantee forward progress for the mempool
in this case, get rid of the mempool and simply allocate memory through
kmalloc.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: decouple read/erase mempools
Javier González [Fri, 13 Oct 2017 12:46:08 +0000 (14:46 +0200)]
lightnvm: pblk: decouple read/erase mempools

Since read and erase paths offer different guarantees for inflight I/Os,
separate the mempools to set the right min_nr for each on creation.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: simplify work_queue mempool
Javier González [Fri, 13 Oct 2017 12:46:07 +0000 (14:46 +0200)]
lightnvm: pblk: simplify work_queue mempool

In pblk, we have a mempool to allocate a generic structure that we
pass along workqueues. This is heavily used in the GC path in order
to have enough inflight reads and fully utilize the GC bandwidth.

However, the current GC path copies data to the host memory and puts it
back into the write buffer. This requires a vmalloc allocation for the
data and a memory copy. Thus, guaranteeing the allocation by using a
mempool for the structure in itself does not give us much. Until we
implement support for vector copy to avoid moving data through the host,
just allocate the workqueue structure using kmalloc.

This allows us to have a much smaller mempool.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: fix min size for page mempool
Javier González [Fri, 13 Oct 2017 12:46:06 +0000 (14:46 +0200)]
lightnvm: pblk: fix min size for page mempool

pblk uses an internal page mempool for allocating pages on internal
bios. The main two users of this memory pool are partial reads (reads
with some sectors in cache and some on media) and padded writes, which
need to add dummy pages to an existing bio already containing valid
data (and with a large enough bioset allocated). In both cases, the
maximum number of pages per bio is defined by the maximum number of
physical sectors supported by the underlying device.

This patch fixes a bad mempool allocation, where the min_nr of elements
on the pool was fixed (to 16), which is lower than the maximum number
of sectors supported by NVMe (as of the time for this patch). Instead,
use the maximum number of allowed sectors reported by the device.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: avoid deadlock on low LUN config
Javier González [Fri, 13 Oct 2017 12:46:05 +0000 (14:46 +0200)]
lightnvm: pblk: avoid deadlock on low LUN config

On low LUN configurations, make sure not to send bios that are bigger
than the buffer size.

Fixes: a4bd217b4326 ("lightnvm: physical block device (pblk) target")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: fix write I/O sync stat
Javier González [Fri, 13 Oct 2017 12:46:04 +0000 (14:46 +0200)]
lightnvm: pblk: fix write I/O sync stat

Fix stat counter to collect the right number of I/Os being synced on the
completion path.

Fixes: 0880a9aa2d91f ("lightnvm: pblk: delete redundant buffer pointer")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: free padded entries in write buffer
Javier González [Fri, 13 Oct 2017 12:46:03 +0000 (14:46 +0200)]
lightnvm: pblk: free padded entries in write buffer

When a REQ_FLUSH reaches pblk, the bio cannot be directly completed.
Instead, data on the write buffer is flushed and the bio is completed on
the completion pah. This might require some sectors to be padded in
order to guarantee a successful write.

This patch fixes a memory leak on the padded pages. A consequence of
this bad free was that internal bios not containing data (only a flush)
were not being completed.

Fixes: a4bd217b4326 ("lightnvm: physical block device (pblk) target")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: use right flag for GC allocation
Javier González [Fri, 13 Oct 2017 12:46:02 +0000 (14:46 +0200)]
lightnvm: pblk: use right flag for GC allocation

The data buffer for the GC path allocates virtual memory through
vmalloc. When this change was introduced, a flag signaling kmalloc'ed
memory was wrongly introduced. Use the right flag when creating a bio
from this buffer.

Fixes: de54e703a422 ("lightnvm: pblk: use vmalloc for GC data buffer")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: initialize debug stat counter
Javier González [Fri, 13 Oct 2017 12:46:01 +0000 (14:46 +0200)]
lightnvm: pblk: initialize debug stat counter

Initialize the stat counter for garbage collected reads.

Fixes: a4bd217b43268 ("lightnvm: physical block device (pblk) target")
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: reuse pblk_gc_should_kick
Rakesh Pandit [Fri, 13 Oct 2017 12:46:00 +0000 (14:46 +0200)]
lightnvm: pblk: reuse pblk_gc_should_kick

This is a trivial change which reuses pblk_gc_should_kick instead of
repeating it again in pblk_rl_free_lines_inc.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Made it apply to the common case.
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: print incompatible line version correctly
Rakesh Pandit [Fri, 13 Oct 2017 12:45:59 +0000 (14:45 +0200)]
lightnvm: pblk: print incompatible line version correctly

Correct it by converting little endian to cpu endian and also define
a macro for line version so that maintenance is easy.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: improve error message if down_timeout fails
Rakesh Pandit [Fri, 13 Oct 2017 12:45:58 +0000 (14:45 +0200)]
lightnvm: pblk: improve error message if down_timeout fails

The two pr_err messages are useless as they don't differentiate
error code.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: fix message if L2P MAP is in device
Rakesh Pandit [Fri, 13 Oct 2017 12:45:57 +0000 (14:45 +0200)]
lightnvm: pblk: fix message if L2P MAP is in device

This usually happens if we are developing with qemu and ll2pmode has
default value. Improve description.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: protect line bitmap while submitting meta io
Rakesh Pandit [Fri, 13 Oct 2017 12:45:56 +0000 (14:45 +0200)]
lightnvm: pblk: protect line bitmap while submitting meta io

It seems pblk_dealloc_page would race against pblk_alloc_pages for
line bitmap for sector allocation.The chances are very low but might
as well protect the bitmap properly.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: include NVM Express driver if OCSSD is selected for build
Rakesh Pandit [Fri, 13 Oct 2017 12:45:55 +0000 (14:45 +0200)]
lightnvm: include NVM Express driver if OCSSD is selected for build

Because NVM needs BLK_DEV_NVME, select it automatically if we mark NVM
in config file before building kernel.  Also append PCI to depends as
select doesn't automatically add dependencies.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: pblk: fix error path in pblk_lines_alloc_metadata
Rakesh Pandit [Fri, 13 Oct 2017 12:45:54 +0000 (14:45 +0200)]
lightnvm: pblk: fix error path in pblk_lines_alloc_metadata

Use appropriate memory free calls based on allocation type used and
also fix number of times free is called if kmalloc fails.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: remove already calculated nr_chnls
Rakesh Pandit [Fri, 13 Oct 2017 12:45:53 +0000 (14:45 +0200)]
lightnvm: remove already calculated nr_chnls

Remove repeated calculation for number of channels while creating a
target device.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: protect target type list with correct locks
Rakesh Pandit [Fri, 13 Oct 2017 12:45:52 +0000 (14:45 +0200)]
lightnvm: protect target type list with correct locks

nvm_tgt_types list was protected by wrong lock for NVM_INFO ioctl call
and can race with addition or removal of target types.  Also
unregistering target type was not protected correctly.

Fixes: 5cd907853 ("lightnvm: remove nested lock conflict with mm")
Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: prevent bd removal if busy
Rakesh Pandit [Fri, 13 Oct 2017 12:45:51 +0000 (14:45 +0200)]
lightnvm: prevent bd removal if busy

When a virtual block device is formatted and mounted after creating
with "nvme lnvm create... -t pblk", a removal from "nvm lnvm remove"
would result in this:

446416.309757] bdi-block not registered
[446416.309773] ------------[ cut here ]------------
[446416.309780] WARNING: CPU: 3 PID: 4319 at fs/fs-writeback.c:2159
  __mark_inode_dirty+0x268/0x340

Ideally removal should return -EBUSY as block device is mounted after
formatting.  This patch tries to address this checking if whole device
or any partition of it already mounted or not before removal.

Whole device is checked using "bd_super" member of block device.  This
member is always set once block device has been mounted using a
filesystem.  Another member "bd_part_count" takes care of checking any
if any partitions are under use.  "bd_part_count" is only updated
under locks when partitions are opened or closed (first open and last
release).  This at least does take care sending -EBUSY if removal is
being attempted while whole block device or any partition is mounted.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agolightnvm: prevent target type module removal when in use
Rakesh Pandit [Fri, 13 Oct 2017 12:45:50 +0000 (14:45 +0200)]
lightnvm: prevent target type module removal when in use

If target type module e.g. pblk here is unloaded (rmmod) while module
is in use (after creating target) system crashes.  We fix this by
using module API refcnt.

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agomtip32xx: Clean up unused variables
Christos Gkekas [Thu, 12 Oct 2017 22:15:54 +0000 (23:15 +0100)]
mtip32xx: Clean up unused variables

Remove variables that are set but never used.

Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agofs/block_dev: remove vfs_msg() interface
Rakesh Pandit [Thu, 12 Oct 2017 16:58:10 +0000 (19:58 +0300)]
fs/block_dev: remove vfs_msg() interface

Replaced by pr_err usage in commit ef51042472f5 ("block, dax: move
"select DAX" from BLOCK to FS_DAX")

Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Acked-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblock: set request_list for request
Shaohua Li [Sat, 7 Oct 2017 00:56:00 +0000 (17:56 -0700)]
block: set request_list for request

Legacy queue sets request's request_list, mq doesn't. This makes mq does
the same thing, so we can find cgroup of a request. Note, we really
only use blkg field of request_list, it's pointless to allocate mempool
for request_list in mq case.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblk-stat: delete useless code
Shaohua Li [Sat, 7 Oct 2017 00:55:59 +0000 (17:55 -0700)]
blk-stat: delete useless code

Fix two issues:
- the per-cpu stat flush is unnecessary, nobody uses per-cpu stat except
  sum it to global stat. We can do the calculation there. The flush just
  wastes cpu time.
- some fields are signed int/s64. I don't see the point.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 years agoblk-throttle: fix null pointer dereference while throttling writeback IOs
Jiufei Xue [Tue, 10 Oct 2017 03:13:32 +0000 (11:13 +0800)]
blk-throttle: fix null pointer dereference while throttling writeback IOs

A null pointer dereference can occur when blkcg is removed manually
with writeback IOs inflight. This is caused by the following case:

Writeback kworker submit the bio and set bio->bi_cg_private to tg
in blk_throtl_assoc_bio.
Then we remove the block cgroup manually, the blkg and tg would be
freed if there is no request inflight.
When the submitted bio come back, blk_throtl_bio_endio() fetch the tg
which was already freed.

Fix this by increasing the refcount of blkg in funcion
blk_throtl_assoc_bio() so that the blkg will not be freed until the
bio_endio called.

Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jiufei Xue <jiufei.xjf@alibaba-inc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>