Commit Graph

5631 Commits

Author SHA1 Message Date
Mike Snitzer
fa8db4948f dm: don't use bio_trim() afterall
bio_trim() has an early return, which makes it _not_ idempotent, if the
offset is 0 and the bio's bi_size already matches the requested size.
Prior to DM, all users of bio_trim() were fine with this.  But DM has
exposed the fact that bio_trim()'s early return is incompatible with a
cloned bio whose integrity payload must be trimmed via
bio_integrity_trim().

Fix this by reverting DM back to doing the equivalent of bio_trim() but
in an idempotent manner (so bio_integrity_trim is always performed).

Follow-on work is needed to assess what benefit bio_trim()'s early
return is providing to its existing callers.

Reported-by: Milan Broz <gmazyland@gmail.com>
Fixes: 57c36519e4 ("dm: fix clone_bio() to trigger blk_recount_segments()")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-06 17:24:37 -05:00
Mikulas Patocka
645efa84f6 dm: add memory barrier before waitqueue_active
Block core changes to switch bio-based IO accounting to be percpu had a
side-effect of altering DM core to now rely on calling waitqueue_active
(in both bio-based and request-based) to check if another task is in
dm_wait_for_completion().

A memory barrier is needed before calling waitqueue_active().  DM core
doesn't piggyback on a preceding memory barrier so it must explicitly
use its own.

For more details on why using waitqueue_active() without a preceding
barrier is unsafe, please see the comment before the waitqueue_active()
definition in include/linux/wait.h.

Add the missing memory barrier by switching to using wq_has_sleeper().

Fixes: 6f75723190 ("dm: remove the pending IO accounting")
Fixes: c4576aed8d ("dm: fix request-based dm's use of dm_wait_for_completion")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-02-06 17:24:37 -05:00
Alexei Naberezhnov
483cbbeddd md/raid5: fix 'out of memory' during raid cache recovery
This fixes the case when md array assembly fails because of raid cache recovery
unable to allocate a stripe, despite attempts to replay stripes and increase
cache size. This happens because stripes released by r5c_recovery_replay_stripes
and raid5_set_cache_size don't become available for allocation immediately.
Released stripes first are placed on conf->released_stripes list and require
md thread to merge them on conf->inactive_list before they can be allocated.

Patch allows final allocation attempt during cache recovery to wait for
new stripes to become availabe for allocation.

Cc: linux-raid@vger.kernel.org
Cc: Shaohua Li <shli@kernel.org>
Cc: linux-stable <stable@vger.kernel.org> # 4.10+
Fixes: b4c625c673 ("md/r5cache: r5cache recovery: part 1")
Signed-off-by: Alexei Naberezhnov <anaberezhnov@fb.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
2019-01-28 11:44:40 -08:00
Linus Torvalds
cffd425b90 - Fix DM crypt's parsing of extended IV arguments.
- Fix DM thinp's discard passdown to properly account for extra
   reference that is taken to guard against reallocating a block before a
   discard has been issued.
 
 - Fix bio-based DM's redundant IO accounting that was occurring for bios
   that must be split due to the nature of the DM target (e.g. dm-stripe,
   dm-thinp, etc).
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Merge tag 'for-5.0/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - Fix DM crypt's parsing of extended IV arguments.

 - Fix DM thinp's discard passdown to properly account for extra
   reference that is taken to guard against reallocating a block before
   a discard has been issued.

 - Fix bio-based DM's redundant IO accounting that was occurring for
   bios that must be split due to the nature of the DM target (e.g.
   dm-stripe, dm-thinp, etc).

* tag 'for-5.0/dm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: add missing trace_block_split() to __split_and_process_bio()
  dm: fix dm_wq_work() to only use __split_and_process_bio() if appropriate
  dm: fix redundant IO accounting for bios that need splitting
  dm: fix clone_bio() to trigger blk_recount_segments()
  dm thin: fix passdown_double_checking_shared_status()
  dm crypt: fix parsing of extended IV arguments
2019-01-25 09:07:18 +13:00
Mike Snitzer
075c18c3e1 dm: add missing trace_block_split() to __split_and_process_bio()
Provides useful context about bio splits in blktrace.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-22 13:41:48 -05:00
Mike Snitzer
6548c7c538 dm: fix dm_wq_work() to only use __split_and_process_bio() if appropriate
Otherwise targets that don't support/expect IO splitting could resubmit
bios using code paths with unnecessary IO splitting complexity.

Depends-on: 24113d4878 ("dm: avoid indirect call in __dm_make_request")
Fixes: 978e51ba38 ("dm: optimize bio-based NVMe IO submission")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-22 13:41:40 -05:00
Mike Snitzer
a1e1cb72d9 dm: fix redundant IO accounting for bios that need splitting
The risk of redundant IO accounting was not taken into consideration
when commit 18a25da843 ("dm: ensure bio submission follows a
depth-first tree walk") introduced IO splitting in terms of recursion
via generic_make_request().

Fix this by subtracting the split bio's payload from the IO stats that
were already accounted for by start_io_acct() upon dm_make_request()
entry.  This repeat oscillation of the IO accounting, up then down,
isn't ideal but refactoring DM core's IO splitting to pre-split bios
_before_ they are accounted turned out to be an excessive amount of
change that will need a full development cycle to refine and verify.

Before this fix:

  /dev/mapper/stripe_dev is a 4-way stripe using a 32k chunksize, so
  bios are split on 32k boundaries.

  # fio --name=16M --filename=/dev/mapper/stripe_dev --rw=write --bs=64k --size=16M \
    	--iodepth=1 --ioengine=libaio --direct=1 --refill_buffers

  with debugging added:
  [103898.310264] device-mapper: core: start_io_acct: dm-2 WRITE bio->bi_iter.bi_sector=0 len=128
  [103898.318704] device-mapper: core: __split_and_process_bio: recursing for following split bio:
  [103898.329136] device-mapper: core: start_io_acct: dm-2 WRITE bio->bi_iter.bi_sector=64 len=64
  ...

  16M written yet 136M (278528 * 512b) accounted:
  # cat /sys/block/dm-2/stat | awk '{ print $7 }'
  278528

After this fix:

  16M written and 16M (32768 * 512b) accounted:
  # cat /sys/block/dm-2/stat | awk '{ print $7 }'
  32768

Fixes: 18a25da843 ("dm: ensure bio submission follows a depth-first tree walk")
Cc: stable@vger.kernel.org # 4.16+
Reported-by: Bryan Gurney <bgurney@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-21 11:29:27 -05:00
Mike Snitzer
57c36519e4 dm: fix clone_bio() to trigger blk_recount_segments()
DM's clone_bio() now benefits from using bio_trim() by fixing the fact
that clone_bio() wasn't clearing BIO_SEG_VALID like bio_trim() does;
which triggers blk_recount_segments() via bio_phys_segments().

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-21 11:29:18 -05:00
Joe Thornber
d445bd9cec dm thin: fix passdown_double_checking_shared_status()
Commit 00a0ea33b4 ("dm thin: do not queue freed thin mapping for next
stage processing") changed process_prepared_discard_passdown_pt1() to
increment all the blocks being discarded until after the passdown had
completed to avoid them being prematurely reused.

IO issued to a thin device that breaks sharing with a snapshot, followed
by a discard issued to snapshot(s) that previously shared the block(s),
results in passdown_double_checking_shared_status() being called to
iterate through the blocks double checking their reference count is zero
and issuing the passdown if so.  So a side effect of commit 00a0ea33b4
is passdown_double_checking_shared_status() was broken.

Fix this by checking if the block reference count is greater than 1.
Also, rename dm_pool_block_is_used() to dm_pool_block_is_shared().

Fixes: 00a0ea33b4 ("dm thin: do not queue freed thin mapping for next stage processing")
Cc: stable@vger.kernel.org # 4.9+
Reported-by: ryan.p.norwood@gmail.com
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-15 16:10:41 -05:00
Marcos Paulo de Souza
6251691a92 md: Make bio_alloc_mddev use bio_alloc_bioset
bio_alloc_bioset returns a bio pointer or NULL, so we can avoid storing
the returned data into a new variable.

Acked-by: Guoqing Jiang <gqjiang@suse.com>
Acked-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-14 06:31:56 -07:00
Milan Broz
1856b9f7bc dm crypt: fix parsing of extended IV arguments
The dm-crypt cipher specification in a mapping table is defined as:
  cipher[:keycount]-chainmode-ivmode[:ivopts]
or (new crypt API format):
  capi:cipher_api_spec-ivmode[:ivopts]

For ESSIV, the parameter includes hash specification, for example:
aes-cbc-essiv:sha256

The implementation expected that additional IV option to never include
another dash '-' character.

But, with SHA3, there are names like sha3-256; so the mapping table
parser fails:

dmsetup create test --table "0 8 crypt aes-cbc-essiv:sha3-256 9c1185a5c5e9fc54612808977ee8f5b9e 0 /dev/sdb 0"
  or (new crypt API format)
dmsetup create test --table "0 8 crypt capi:cbc(aes)-essiv:sha3-256 9c1185a5c5e9fc54612808977ee8f5b9e 0 /dev/sdb 0"

  device-mapper: crypt: Ignoring unexpected additional cipher options
  device-mapper: table: 253:0: crypt: Error creating IV
  device-mapper: ioctl: error adding target to table

Fix the dm-crypt constructor to ignore additional dash in IV options and
also remove a bogus warning (that is ignored anyway).

Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-01-10 15:17:33 -05:00
Jens Axboe
dc629c211c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md into for-linus
Pull the pending 4.21 changes for md from Shaohua.

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md:
  md: fix raid10 hang issue caused by barrier
  raid10: refactor common wait code from regular read/write request
  md: remvoe redundant condition check
  lib/raid6: add option to skip algo benchmarking
  lib/raid6: sort algos in rough performance order
  lib/raid6: check for assembler SSSE3 support
  lib/raid6: avoid __attribute_const__ redefinition
  lib/raid6: add missing include for raid6test
  md: remove set but not used variable 'bi_rdev'
2019-01-03 08:21:02 -07:00
Linus Torvalds
f346b0becb Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:

 - large KASAN update to use arm's "software tag-based mode"

 - a few misc things

 - sh updates

 - ocfs2 updates

 - just about all of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (167 commits)
  kernel/fork.c: mark 'stack_vm_area' with __maybe_unused
  memcg, oom: notify on oom killer invocation from the charge path
  mm, swap: fix swapoff with KSM pages
  include/linux/gfp.h: fix typo
  mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
  hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race
  hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
  memory_hotplug: add missing newlines to debugging output
  mm: remove __hugepage_set_anon_rmap()
  include/linux/vmstat.h: remove unused page state adjustment macro
  mm/page_alloc.c: allow error injection
  mm: migrate: drop unused argument of migrate_page_move_mapping()
  blkdev: avoid migration stalls for blkdev pages
  mm: migrate: provide buffer_migrate_page_norefs()
  mm: migrate: move migrate_page_lock_buffers()
  mm: migrate: lock buffers before migrate_page_move_mapping()
  mm: migration: factor out code to compute expected number of page references
  mm, page_alloc: enable pcpu_drain with zone capability
  kmemleak: add config to select auto scan
  mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init
  ...
2018-12-28 16:55:46 -08:00
Linus Torvalds
4ed7bdc1eb - Eliminate a couple indirect calls from bio-based DM core.
- Fix DM to allow reads that exceed readahead limits by setting io_pages
   in the backing_dev_info.
 
 - A couple code cleanups in request-based DM.
 
 - Fix various DM targets to check for device sector overflow if
   CONFIG_LBDAF is not set.
 
 - Use u64 instead of sector_t to store iv_offset in DM crypt; sector_t
   isn't large enough on 32bit when CONFIG_LBDAF is not set.
 
 - Performance fixes to DM's kcopyd and the snapshot target focused on
   limiting memory use and workqueue stalls.
 
 - Fix typos in the integrity and writecache targets.
 
 - Log which algorithm is used for dm-crypt's encryption and
   dm-integrity's hashing.
 
 - Fix false -EBUSY errors in DM raid target's handling of check/repair
   messages.
 
 - Fix DM flakey target's corrupt_bio_byte feature to reliably corrupt
   the Nth byte in a bio's payload.
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Merge tag 'for-4.21/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Eliminate a couple indirect calls from bio-based DM core.

 - Fix DM to allow reads that exceed readahead limits by setting
   io_pages in the backing_dev_info.

 - A couple code cleanups in request-based DM.

 - Fix various DM targets to check for device sector overflow if
   CONFIG_LBDAF is not set.

 - Use u64 instead of sector_t to store iv_offset in DM crypt; sector_t
   isn't large enough on 32bit when CONFIG_LBDAF is not set.

 - Performance fixes to DM's kcopyd and the snapshot target focused on
   limiting memory use and workqueue stalls.

 - Fix typos in the integrity and writecache targets.

 - Log which algorithm is used for dm-crypt's encryption and
   dm-integrity's hashing.

 - Fix false -EBUSY errors in DM raid target's handling of check/repair
   messages.

 - Fix DM flakey target's corrupt_bio_byte feature to reliably corrupt
   the Nth byte in a bio's payload.

* tag 'for-4.21/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: do not allow readahead to limit IO size
  dm raid: fix false -EBUSY when handling check/repair message
  dm rq: cleanup leftover code from recently removed q->mq_ops branching
  dm verity: log the hash algorithm implementation
  dm crypt: log the encryption algorithm implementation
  dm integrity: fix spelling mistake in workqueue name
  dm flakey: Properly corrupt multi-page bios.
  dm: Check for device sector overflow if CONFIG_LBDAF is not set
  dm crypt: use u64 instead of sector_t to store iv_offset
  dm kcopyd: Fix bug causing workqueue stalls
  dm snapshot: Fix excessive memory usage and workqueue stalls
  dm bufio: update comment in dm-bufio.c
  dm writecache: fix typo in error msg for creating writecache_flush_thread
  dm: remove indirect calls from __send_changing_extent_only()
  dm mpath: only flush workqueue when needed
  dm rq: remove unused arguments from rq_completed()
  dm: avoid indirect call in __dm_make_request
2018-12-28 15:02:26 -08:00
Linus Torvalds
0e9da3fbf7 for-4.21/block-20181221
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Merge tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
 "This is the main pull request for block/storage for 4.21.

  Larger than usual, it was a busy round with lots of goodies queued up.
  Most notable is the removal of the old IO stack, which has been a long
  time coming. No new features for a while, everything coming in this
  week has all been fixes for things that were previously merged.

  This contains:

   - Use atomic counters instead of semaphores for mtip32xx (Arnd)

   - Cleanup of the mtip32xx request setup (Christoph)

   - Fix for circular locking dependency in loop (Jan, Tetsuo)

   - bcache (Coly, Guoju, Shenghui)
      * Optimizations for writeback caching
      * Various fixes and improvements

   - nvme (Chaitanya, Christoph, Sagi, Jay, me, Keith)
      * host and target support for NVMe over TCP
      * Error log page support
      * Support for separate read/write/poll queues
      * Much improved polling
      * discard OOM fallback
      * Tracepoint improvements

   - lightnvm (Hans, Hua, Igor, Matias, Javier)
      * Igor added packed metadata to pblk. Now drives without metadata
        per LBA can be used as well.
      * Fix from Geert on uninitialized value on chunk metadata reads.
      * Fixes from Hans and Javier to pblk recovery and write path.
      * Fix from Hua Su to fix a race condition in the pblk recovery
        code.
      * Scan optimization added to pblk recovery from Zhoujie.
      * Small geometry cleanup from me.

   - Conversion of the last few drivers that used the legacy path to
     blk-mq (me)

   - Removal of legacy IO path in SCSI (me, Christoph)

   - Removal of legacy IO stack and schedulers (me)

   - Support for much better polling, now without interrupts at all.
     blk-mq adds support for multiple queue maps, which enables us to
     have a map per type. This in turn enables nvme to have separate
     completion queues for polling, which can then be interrupt-less.
     Also means we're ready for async polled IO, which is hopefully
     coming in the next release.

   - Killing of (now) unused block exports (Christoph)

   - Unification of the blk-rq-qos and blk-wbt wait handling (Josef)

   - Support for zoned testing with null_blk (Masato)

   - sx8 conversion to per-host tag sets (Christoph)

   - IO priority improvements (Damien)

   - mq-deadline zoned fix (Damien)

   - Ref count blkcg series (Dennis)

   - Lots of blk-mq improvements and speedups (me)

   - sbitmap scalability improvements (me)

   - Make core inflight IO accounting per-cpu (Mikulas)

   - Export timeout setting in sysfs (Weiping)

   - Cleanup the direct issue path (Jianchao)

   - Export blk-wbt internals in block debugfs for easier debugging
     (Ming)

   - Lots of other fixes and improvements"

* tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block: (364 commits)
  kyber: use sbitmap add_wait_queue/list_del wait helpers
  sbitmap: add helpers for add/del wait queue handling
  block: save irq state in blkg_lookup_create()
  dm: don't reuse bio for flushes
  nvme-pci: trace SQ status on completions
  nvme-rdma: implement polling queue map
  nvme-fabrics: allow user to pass in nr_poll_queues
  nvme-fabrics: allow nvmf_connect_io_queue to poll
  nvme-core: optionally poll sync commands
  block: make request_to_qc_t public
  nvme-tcp: fix spelling mistake "attepmpt" -> "attempt"
  nvme-tcp: fix endianess annotations
  nvmet-tcp: fix endianess annotations
  nvme-pci: refactor nvme_poll_irqdisable to make sparse happy
  nvme-pci: only set nr_maps to 2 if poll queues are supported
  nvmet: use a macro for default error location
  nvmet: fix comparison of a u16 with -1
  blk-mq: enable IO poll if .nr_queues of type poll > 0
  blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()
  blk-mq: skip zero-queue maps in blk_mq_map_swqueue
  ...
2018-12-28 13:19:59 -08:00
Arun KS
ca79b0c211 mm: convert totalram_pages and totalhigh_pages variables to atomic
totalram_pages and totalhigh_pages are made static inline function.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Linus Torvalds
b71acb0e37 Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
 "API:
   - Add 1472-byte test to tcrypt for IPsec
   - Reintroduced crypto stats interface with numerous changes
   - Support incremental algorithm dumps

  Algorithms:
   - Add xchacha12/20
   - Add nhpoly1305
   - Add adiantum
   - Add streebog hash
   - Mark cts(cbc(aes)) as FIPS allowed

  Drivers:
   - Improve performance of arm64/chacha20
   - Improve performance of x86/chacha20
   - Add NEON-accelerated nhpoly1305
   - Add SSE2 accelerated nhpoly1305
   - Add AVX2 accelerated nhpoly1305
   - Add support for 192/256-bit keys in gcmaes AVX
   - Add SG support in gcmaes AVX
   - ESN for inline IPsec tx in chcr
   - Add support for CryptoCell 703 in ccree
   - Add support for CryptoCell 713 in ccree
   - Add SM4 support in ccree
   - Add SM3 support in ccree
   - Add support for chacha20 in caam/qi2
   - Add support for chacha20 + poly1305 in caam/jr
   - Add support for chacha20 + poly1305 in caam/qi2
   - Add AEAD cipher support in cavium/nitrox"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (130 commits)
  crypto: skcipher - remove remnants of internal IV generators
  crypto: cavium/nitrox - Fix build with !CONFIG_DEBUG_FS
  crypto: salsa20-generic - don't unnecessarily use atomic walk
  crypto: skcipher - add might_sleep() to skcipher_walk_virt()
  crypto: x86/chacha - avoid sleeping under kernel_fpu_begin()
  crypto: cavium/nitrox - Added AEAD cipher support
  crypto: mxc-scc - fix build warnings on ARM64
  crypto: api - document missing stats member
  crypto: user - remove unused dump functions
  crypto: chelsio - Fix wrong error counter increments
  crypto: chelsio - Reset counters on cxgb4 Detach
  crypto: chelsio - Handle PCI shutdown event
  crypto: chelsio - cleanup:send addr as value in function argument
  crypto: chelsio - Use same value for both channel in single WR
  crypto: chelsio - Swap location of AAD and IV sent in WR
  crypto: chelsio - remove set but not used variable 'kctx_len'
  crypto: ux500 - Use proper enum in hash_set_dma_transfer
  crypto: ux500 - Use proper enum in cryp_set_dma_transfer
  crypto: aesni - Add scatter/gather avx stubs, and use them in C
  crypto: aesni - Introduce partial block macro
  ..
2018-12-27 13:53:32 -08:00
Guoqing Jiang
e820d55cb9 md: fix raid10 hang issue caused by barrier
When both regular IO and resync IO happen at the same time,
and if we also need to split regular. Then we can see tasks
hang due to barrier.

1. resync thread
[ 1463.757205] INFO: task md1_resync:5215 blocked for more than 480 seconds.
[ 1463.757207]       Not tainted 4.19.5-1-default #1
[ 1463.757209] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1463.757212] md1_resync      D    0  5215      2 0x80000000
[ 1463.757216] Call Trace:
[ 1463.757223]  ? __schedule+0x29a/0x880
[ 1463.757231]  ? raise_barrier+0x8d/0x140 [raid10]
[ 1463.757236]  schedule+0x78/0x110
[ 1463.757243]  raise_barrier+0x8d/0x140 [raid10]
[ 1463.757248]  ? wait_woken+0x80/0x80
[ 1463.757257]  raid10_sync_request+0x1f6/0x1e30 [raid10]
[ 1463.757265]  ? _raw_spin_unlock_irq+0x22/0x40
[ 1463.757284]  ? is_mddev_idle+0x125/0x137 [md_mod]
[ 1463.757302]  md_do_sync.cold.78+0x404/0x969 [md_mod]
[ 1463.757311]  ? wait_woken+0x80/0x80
[ 1463.757336]  ? md_rdev_init+0xb0/0xb0 [md_mod]
[ 1463.757351]  md_thread+0xe9/0x140 [md_mod]
[ 1463.757358]  ? _raw_spin_unlock_irqrestore+0x2e/0x60
[ 1463.757364]  ? __kthread_parkme+0x4c/0x70
[ 1463.757369]  kthread+0x112/0x130
[ 1463.757374]  ? kthread_create_worker_on_cpu+0x40/0x40
[ 1463.757380]  ret_from_fork+0x3a/0x50

2. regular IO
[ 1463.760679] INFO: task kworker/0:8:5367 blocked for more than 480 seconds.
[ 1463.760683]       Not tainted 4.19.5-1-default #1
[ 1463.760684] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1463.760687] kworker/0:8     D    0  5367      2 0x80000000
[ 1463.760718] Workqueue: md submit_flushes [md_mod]
[ 1463.760721] Call Trace:
[ 1463.760731]  ? __schedule+0x29a/0x880
[ 1463.760741]  ? wait_barrier+0xdd/0x170 [raid10]
[ 1463.760746]  schedule+0x78/0x110
[ 1463.760753]  wait_barrier+0xdd/0x170 [raid10]
[ 1463.760761]  ? wait_woken+0x80/0x80
[ 1463.760768]  raid10_write_request+0xf2/0x900 [raid10]
[ 1463.760774]  ? wait_woken+0x80/0x80
[ 1463.760778]  ? mempool_alloc+0x55/0x160
[ 1463.760795]  ? md_write_start+0xa9/0x270 [md_mod]
[ 1463.760801]  ? try_to_wake_up+0x44/0x470
[ 1463.760810]  raid10_make_request+0xc1/0x120 [raid10]
[ 1463.760816]  ? wait_woken+0x80/0x80
[ 1463.760831]  md_handle_request+0x121/0x190 [md_mod]
[ 1463.760851]  md_make_request+0x78/0x190 [md_mod]
[ 1463.760860]  generic_make_request+0x1c6/0x470
[ 1463.760870]  raid10_write_request+0x77a/0x900 [raid10]
[ 1463.760875]  ? wait_woken+0x80/0x80
[ 1463.760879]  ? mempool_alloc+0x55/0x160
[ 1463.760895]  ? md_write_start+0xa9/0x270 [md_mod]
[ 1463.760904]  raid10_make_request+0xc1/0x120 [raid10]
[ 1463.760910]  ? wait_woken+0x80/0x80
[ 1463.760926]  md_handle_request+0x121/0x190 [md_mod]
[ 1463.760931]  ? _raw_spin_unlock_irq+0x22/0x40
[ 1463.760936]  ? finish_task_switch+0x74/0x260
[ 1463.760954]  submit_flushes+0x21/0x40 [md_mod]

So resync io is waiting for regular write io to complete to
decrease nr_pending (conf->barrier++ is called before waiting).
The regular write io splits another bio after call wait_barrier
which call nr_pending++, then the splitted bio would continue
with raid10_write_request -> wait_barrier, so the splitted bio
has to wait for barrier to be zero, then deadlock happens as
follows.

	resync io		regular io

	raise_barrier
				wait_barrier
				generic_make_request
				wait_barrier

To resolve the issue, we need to call allow_barrier to decrease
nr_pending before generic_make_request since regular IO is not
issued to underlying devices, and wait_barrier is called again
to ensure no internal IO happening.

Fixes: fc9977dd06 ("md/raid10: simplify the splitting of requests.")
Reported-and-tested-by: Siniša Bandin <sinisa@4net.rs>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2018-12-20 08:53:24 -08:00
Guoqing Jiang
caea3c47ad raid10: refactor common wait code from regular read/write request
Both raid10_read_request and raid10_write_request share
the same code at the beginning of them, so introduce
regular_request_wait to clean up code, and call it in
both request functions.

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2018-12-20 08:53:24 -08:00
Chengguang Xu
37b22c2894 md: remvoe redundant condition check
mempool_destroy() can handle NULL pointer correctly,
so there is no need to check NULL pointer before calling
mempool_destroy().

Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2018-12-20 08:53:24 -08:00
Yue Haibing
f91389c8d2 md: remove set but not used variable 'bi_rdev'
Fixes gcc '-Wunused-but-set-variable' warning:

drivers/md/md.c: In function 'md_integrity_add_rdev':
drivers/md/md.c:2149:24: warning:
 variable 'bi_rdev' set but not used [-Wunused-but-set-variable]

It not used any more after commit
  1501efadc5 ("md/raid: only permit hot-add of compatible integrity profiles")

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Signed-off-by: Shaohua Li <shli@fb.com>
2018-12-20 08:53:23 -08:00
Jens Axboe
dbe3ece128 dm: don't reuse bio for flushes
DM currently has a statically allocated bio that it uses to issue empty
flushes. It doesn't submit this bio, it just uses it for maintaining
state while setting up clones. Multiple users can access this bio at the
same time. This wasn't previously an issue, even if it was a bit iffy,
but with the blkg associations it can become one.

We setup the blkg association, then clone bio's and submit, then remove
the blkg assocation again. But since we can have multiple tasks doing
this at the same time, against multiple blkg's, then we can either lose
references to a blkg, or put it twice. The latter causes complaints on
the percpu ref being <= 0 when released, and can cause use-after-free as
well. Ming reports that xfstest generic/475 triggers this:

------------[ cut here ]------------
percpu ref (blkg_release) <= 0 (0) after switching to atomic
WARNING: CPU: 13 PID: 0 at lib/percpu-refcount.c:155 percpu_ref_switch_to_atomic_rcu+0x2c9/0x4a0

Switch to just using an on-stack bio for this, and get rid of the
embedded bio.

Fixes: 5cdf2e3fea ("blkcg: associate blkg when associating a device")
Reported-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-19 09:13:34 -07:00
Jaegeuk Kim
c6d6e9b0f6 dm: do not allow readahead to limit IO size
Update DM to set the bdi's io_pages.  This fixes reads to be capped at
the device's max request size (even if user's read IO exceeds the
established readahead setting).

Fixes: 9491ae4a ("mm: don't cap request size based on read-ahead setting")
Cc: stable@vger.kernel.org
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 14:23:41 -05:00
Heinz Mauelshagen
74694bcbdf dm raid: fix false -EBUSY when handling check/repair message
Sending a check/repair message infrequently leads to -EBUSY instead of
properly identifying an active resync.  This occurs because
raid_message() is testing recovery bits in a racy way.

Fix by calling decipher_sync_action() from raid_message() to properly
identify the idle state of the RAID device.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 13:48:35 -05:00
Mike Snitzer
34743bfdde dm rq: cleanup leftover code from recently removed q->mq_ops branching
When commit 6a23e05c2f ("dm: remove legacy request-based IO path")
removed some q->mq_ops branching from map_request() it left in place a
goto that was only needed if that branching (and conditional 'r'
assignment) existed.  Now that the branching is gone map_request()'s
goto can be removed too.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:27 -05:00
Eric Biggers
bbf6a56692 dm verity: log the hash algorithm implementation
Log the hash algorithm's driver name when a dm-verity target is created.
This will help people determine whether the expected implementation is
being used.  It can make an enormous difference; e.g., SHA-256 on ARM
can be 8x faster with the crypto extensions than without.  It can also
be useful to know if an implementation using an external crypto
accelerator is being used instead of a software implementation.

Example message:

[   35.281945] device-mapper: verity: sha256 using implementation "sha256-ce"

We've already found the similar message in fs/crypto/keyinfo.c to be
very useful.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:27 -05:00
Eric Biggers
af331ebae7 dm crypt: log the encryption algorithm implementation
Log the encryption algorithm's driver name when a dm-crypt target is
created.  This will help people determine whether the expected
implementation is being used.  In some cases we've seen people do
benchmarks and reject using encryption for performance reasons, when in
fact they used a much slower implementation than was possible on the
hardware.  It can make an enormous difference; e.g., AES-XTS on ARM can
be over 10x faster with the crypto extensions than without.  It can also
be useful to know if an implementation using an external crypto
accelerator is being used instead of a software implementation.

Example message:

[   29.307629] device-mapper: crypt: xts(aes) using implementation "xts-aes-ce"

We've already found the similar message in fs/crypto/keyinfo.c to be
very useful.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:27 -05:00
Colin Ian King
e8c2566f83 dm integrity: fix spelling mistake in workqueue name
Rename the workqueue from dm-intergrity-recalc to dm-integrity-recalc.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:27 -05:00
Sweet Tea
a00f5276e2 dm flakey: Properly corrupt multi-page bios.
The flakey target is documented to be able to corrupt the Nth byte in
a bio, but does not corrupt byte indices after the first biovec in the
bio. Change the corrupting function to actually corrupt the Nth byte
no matter in which biovec that index falls.

A test device generating two-page bios, atop a flakey device configured
to corrupt a byte index on the second page, verified both the failure
to corrupt before this patch and the expected corruption after this
change.

Signed-off-by: John Dorminy <jdorminy@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:27 -05:00
Milan Broz
ef87bfc24f dm: Check for device sector overflow if CONFIG_LBDAF is not set
Reference to a device in device-mapper table contains offset in sectors.

If the sector_t is 32bit integer (CONFIG_LBDAF is not set), then
several device-mapper targets can overflow this offset and validity
check is then performed on a wrong offset and a wrong table is activated.

See for example (on 32bit without CONFIG_LBDAF) this overflow:

  # dmsetup create test --table "0 2048 linear /dev/sdg 4294967297"
  # dmsetup table test
  0 2048 linear 8:96 1

This patch adds explicit check for overflow if the offset is sector_t type.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
AliOS system security
8d683dcd65 dm crypt: use u64 instead of sector_t to store iv_offset
The iv_offset in the mapping table of crypt target is a 64bit number when
IV algorithm is plain64, plain64be, essiv or benbi. It will be assigned to
iv_offset of struct crypt_config, cc_sector of struct convert_context and
iv_sector of struct dm_crypt_request. These structures members are defined
as a sector_t. But sector_t is 32bit when CONFIG_LBDAF is not set in 32bit
kernel. In this situation sector_t is not big enough to store the 64bit
iv_offset.

Here is a reproducer.
Prepare test image and device (loop is automatically allocated by cryptsetup):

  # dd if=/dev/zero of=tst.img bs=1M count=1
  # echo "tst"|cryptsetup open --type plain -c aes-xts-plain64 \
  --skip 500000000000000000 tst.img test

On 32bit system (use IV offset value that overflows to 64bit; CONFIG_LBDAF if off)
and device checksum is wrong:

  # dmsetup table test --showkeys
  0 2048 crypt aes-xts-plain64 dfa7cfe3c481f2239155739c42e539ae8f2d38f304dcc89d20b26f69daaf0933 3551657984 7:0 0

  # sha256sum /dev/mapper/test
  533e25c09176632b3794f35303488c4a8f3f965dffffa6ec2df347c168cb6c19 /dev/mapper/test

On 64bit system (and on 32bit system with the patch), table and checksum is now correct:

  # dmsetup table test --showkeys
  0 2048 crypt aes-xts-plain64 dfa7cfe3c481f2239155739c42e539ae8f2d38f304dcc89d20b26f69daaf0933 500000000000000000 7:0 0

  # sha256sum /dev/mapper/test
  5d16160f9d5f8c33d8051e65fdb4f003cc31cd652b5abb08f03aa6fce0df75fc /dev/mapper/test

Signed-off-by: AliOS system security <alios_sys_security@linux.alibaba.com>
Tested-and-Reviewed-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
Nikos Tsironis
d7e6b8dfc7 dm kcopyd: Fix bug causing workqueue stalls
When using kcopyd to run callbacks through dm_kcopyd_do_callback() or
submitting copy jobs with a source size of 0, the jobs are pushed
directly to the complete_jobs list, which could be under processing by
the kcopyd thread. As a result, the kcopyd thread can continue running
completed jobs indefinitely, without releasing the CPU, as long as
someone keeps submitting new completed jobs through the aforementioned
paths. Processing of work items, queued for execution on the same CPU as
the currently running kcopyd thread, is thus stalled for excessive
amounts of time, hurting performance.

Running the following test, from the device mapper test suite [1],

  dmtest run --suite snapshot -n parallel_io_to_many_snaps_N

, with 8 active snapshots, we get, in dmesg, messages like the
following:

[68899.948523] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 95s!
[68899.949282] Showing busy workqueues and worker pools:
[68899.949288] workqueue events: flags=0x0
[68899.949295]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
[68899.949306]     pending: vmstat_shepherd, cache_reap
[68899.949331] workqueue mm_percpu_wq: flags=0x8
[68899.949337]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[68899.949345]     pending: vmstat_update
[68899.949387] workqueue dm_bufio_cache: flags=0x8
[68899.949392]   pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=1/256
[68899.949400]     pending: work_fn [dm_bufio]
[68899.949423] workqueue kcopyd: flags=0x8
[68899.949429]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[68899.949437]     pending: do_work [dm_mod]
[68899.949452] workqueue kcopyd: flags=0x8
[68899.949458]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
[68899.949466]     in-flight: 13:do_work [dm_mod]
[68899.949474]     pending: do_work [dm_mod]
[68899.949487] workqueue kcopyd: flags=0x8
[68899.949493]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[68899.949501]     pending: do_work [dm_mod]
[68899.949515] workqueue kcopyd: flags=0x8
[68899.949521]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[68899.949529]     pending: do_work [dm_mod]
[68899.949541] workqueue kcopyd: flags=0x8
[68899.949547]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[68899.949555]     pending: do_work [dm_mod]
[68899.949568] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=95s workers=4 idle: 27130 27223 1084

Fix this by splitting the complete_jobs list into two parts: A user
facing part, named callback_jobs, and one used internally by kcopyd,
retaining the name complete_jobs. dm_kcopyd_do_callback() and
dispatch_job() now push their jobs to the callback_jobs list, which is
spliced to the complete_jobs list once, every time the kcopyd thread
wakes up. This prevents kcopyd from hogging the CPU indefinitely and
causing workqueue stalls.

Re-running the aforementioned test:

  * Workqueue stalls are eliminated
  * The maximum writing time among all targets is reduced from 09m37.10s
    to 06m04.85s and the total run time of the test is reduced from
    10m43.591s to 7m19.199s

[1] https://github.com/jthornber/device-mapper-test-suite

Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
Nikos Tsironis
721b1d98fb dm snapshot: Fix excessive memory usage and workqueue stalls
kcopyd has no upper limit to the number of jobs one can allocate and
issue. Under certain workloads this can lead to excessive memory usage
and workqueue stalls. For example, when creating multiple dm-snapshot
targets with a 4K chunk size and then writing to the origin through the
page cache. Syncing the page cache causes a large number of BIOs to be
issued to the dm-snapshot origin target, which itself issues an even
larger (because of the BIO splitting taking place) number of kcopyd
jobs.

Running the following test, from the device mapper test suite [1],

  dmtest run --suite snapshot -n many_snapshots_of_same_volume_N

, with 8 active snapshots, results in the kcopyd job slab cache growing
to 10G. Depending on the available system RAM this can lead to the OOM
killer killing user processes:

[463.492878] kthreadd invoked oom-killer: gfp_mask=0x6040c0(GFP_KERNEL|__GFP_COMP),
              nodemask=(null), order=1, oom_score_adj=0
[463.492894] kthreadd cpuset=/ mems_allowed=0
[463.492948] CPU: 7 PID: 2 Comm: kthreadd Not tainted 4.19.0-rc7 #3
[463.492950] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[463.492952] Call Trace:
[463.492964]  dump_stack+0x7d/0xbb
[463.492973]  dump_header+0x6b/0x2fc
[463.492987]  ? lockdep_hardirqs_on+0xee/0x190
[463.493012]  oom_kill_process+0x302/0x370
[463.493021]  out_of_memory+0x113/0x560
[463.493030]  __alloc_pages_slowpath+0xf40/0x1020
[463.493055]  __alloc_pages_nodemask+0x348/0x3c0
[463.493067]  cache_grow_begin+0x81/0x8b0
[463.493072]  ? cache_grow_begin+0x874/0x8b0
[463.493078]  fallback_alloc+0x1e4/0x280
[463.493092]  kmem_cache_alloc_node+0xd6/0x370
[463.493098]  ? copy_process.part.31+0x1c5/0x20d0
[463.493105]  copy_process.part.31+0x1c5/0x20d0
[463.493115]  ? __lock_acquire+0x3cc/0x1550
[463.493121]  ? __switch_to_asm+0x34/0x70
[463.493129]  ? kthread_create_worker_on_cpu+0x70/0x70
[463.493135]  ? finish_task_switch+0x90/0x280
[463.493165]  _do_fork+0xe0/0x6d0
[463.493191]  ? kthreadd+0x19f/0x220
[463.493233]  kernel_thread+0x25/0x30
[463.493235]  kthreadd+0x1bf/0x220
[463.493242]  ? kthread_create_on_cpu+0x90/0x90
[463.493248]  ret_from_fork+0x3a/0x50
[463.493279] Mem-Info:
[463.493285] active_anon:20631 inactive_anon:4831 isolated_anon:0
[463.493285]  active_file:80216 inactive_file:80107 isolated_file:435
[463.493285]  unevictable:0 dirty:51266 writeback:109372 unstable:0
[463.493285]  slab_reclaimable:31191 slab_unreclaimable:3483521
[463.493285]  mapped:526 shmem:4903 pagetables:1759 bounce:0
[463.493285]  free:33623 free_pcp:2392 free_cma:0
...
[463.493489] Unreclaimable slab info:
[463.493513] Name                      Used          Total
[463.493522] bio-6                   1028KB       1028KB
[463.493525] bio-5                   1028KB       1028KB
[463.493528] dm_snap_pending_exception     236783KB     243789KB
[463.493531] dm_exception              41KB         42KB
[463.493534] bio-4                   1216KB       1216KB
[463.493537] bio-3                 439396KB     439396KB
[463.493539] kcopyd_job           6973427KB    6973427KB
...
[463.494340] Out of memory: Kill process 1298 (ruby2.3) score 1 or sacrifice child
[463.494673] Killed process 1298 (ruby2.3) total-vm:435740kB, anon-rss:20180kB, file-rss:4kB, shmem-rss:0kB
[463.506437] oom_reaper: reaped process 1298 (ruby2.3), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

Moreover, issuing a large number of kcopyd jobs results in kcopyd
hogging the CPU, while processing them. As a result, processing of work
items, queued for execution on the same CPU as the currently running
kcopyd thread, is stalled for long periods of time, hurting performance.
Running the aforementioned test we get, in dmesg, messages like the
following:

[67501.194592] BUG: workqueue lockup - pool cpus=4 node=0 flags=0x0 nice=0 stuck for 27s!
[67501.195586] Showing busy workqueues and worker pools:
[67501.195591] workqueue events: flags=0x0
[67501.195597]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
[67501.195611]     pending: cache_reap
[67501.195641] workqueue mm_percpu_wq: flags=0x8
[67501.195645]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
[67501.195656]     pending: vmstat_update
[67501.195682] workqueue kblockd: flags=0x18
[67501.195687]   pwq 5: cpus=2 node=0 flags=0x0 nice=-20 active=1/256
[67501.195698]     pending: blk_timeout_work
[67501.195753] workqueue kcopyd: flags=0x8
[67501.195757]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
[67501.195768]     pending: do_work [dm_mod]
[67501.195802] workqueue kcopyd: flags=0x8
[67501.195806]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
[67501.195817]     pending: do_work [dm_mod]
[67501.195834] workqueue kcopyd: flags=0x8
[67501.195838]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
[67501.195848]     pending: do_work [dm_mod]
[67501.195881] workqueue kcopyd: flags=0x8
[67501.195885]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
[67501.195896]     pending: do_work [dm_mod]
[67501.195920] workqueue kcopyd: flags=0x8
[67501.195924]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=2/256
[67501.195935]     in-flight: 67:do_work [dm_mod]
[67501.195945]     pending: do_work [dm_mod]
[67501.195961] pool 8: cpus=4 node=0 flags=0x0 nice=0 hung=27s workers=3 idle: 129 23765

The root cause for these issues is the way dm-snapshot uses kcopyd. In
particular, the lack of an explicit or implicit limit to the maximum
number of in-flight COW jobs. The merging path is not affected because
it implicitly limits the in-flight kcopyd jobs to one.

Fix these issues by using a semaphore to limit the maximum number of
in-flight kcopyd jobs. We grab the semaphore before allocating a new
kcopyd job in start_copy() and start_full_bio() and release it after the
job finishes in copy_callback().

The initial semaphore value is configurable through a module parameter,
to allow fine tuning the maximum number of in-flight COW jobs. Setting
this parameter to zero initializes the semaphore to INT_MAX.

A default value of 2048 maximum in-flight kcopyd jobs was chosen. This
value was decided experimentally as a trade-off between memory
consumption, stalling the kernel's workqueues and maintaining a high
enough throughput.

Re-running the aforementioned test:

  * Workqueue stalls are eliminated
  * kcopyd's job slab cache uses a maximum of 130MB
  * The time taken by the test to write to the snapshot-origin target is
    reduced from 05m20.48s to 03m26.38s

[1] https://github.com/jthornber/device-mapper-test-suite

Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Signed-off-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
Shenghui Wang
ef9923739e dm bufio: update comment in dm-bufio.c
* Hashtable has been replaced by rbtree to manage buffers.
  Update the comment.
* Fix typo in the comment for dm_bufio_issue_flush

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
Shenghui Wang
e8ea141a0f dm writecache: fix typo in error msg for creating writecache_flush_thread
The error msg should be "flush thread" instead of "endio thread"
for writecache_flush_thread.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
Mike Snitzer
53b4716870 dm: remove indirect calls from __send_changing_extent_only()
No need to be so fancy.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:26 -05:00
wuzhouhui
935fcc56ab dm mpath: only flush workqueue when needed
The workqueues are shared by many multipath devices, only flush whole
workqueue when necessary.  Otherwise, we just flush works as needed.

Signed-off-by: wuzhouhui <wuzhouhui14@mails.ucas.ac.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:25 -05:00
Mike Snitzer
2adc5c559a dm rq: remove unused arguments from rq_completed()
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:25 -05:00
Mikulas Patocka
24113d4878 dm: avoid indirect call in __dm_make_request
Indirect calls are inefficient because of retpolines that are used for
spectre workaround. This patch replaces an indirect call with a condition
(that can be predicted by the branch predictor).

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18 09:02:25 -05:00
Jens Axboe
3c94d83cb3 blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()
There's a single user of this function, dm, and dm just wants
to check if IO is inflight, not that it's just allocated.

This fixes a hang with srp/002 in blktests with dm, where it tries
to suspend but waits for inflight IO to finish first. As it checks
for just allocated requests, this fails.

Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-17 21:31:42 -07:00
Guoju Fang
e78bd0d26f bcache: print number of keys in trace_bcache_journal_write
Sometimes flush journal may be very frequent, so it's useful to dump
number of keys every time write journal.

Signed-off-by: Guoju Fang <fangguoju@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li
cc38ca7ed5 bcache: set writeback_percent in a flexible range
Because CUTOFF_WRITEBACK is defined as 40, so before the changes of
dynamic cutoff writeback values, writeback_percent is limited to [0,
CUTOFF_WRITEBACK]. Any value larger than CUTOFF_WRITEBACK will be fixed
up to 40.

Now cutof writeback limit is a dynamic value bch_cutoff_writeback, so
the range of writeback_percent can be a more flexible range as [0,
bch_cutoff_writeback]. The flexibility is, it can be expended to a
larger or smaller range than [0, 40], depends on how value
bch_cutoff_writeback is specified.

The default value is still strongly recommended to most of users for
most of workloads. But for people who want to do research on bcache
writeback perforamnce tuning, they may have chance to specify more
flexible writeback_percent in range [0, 70].

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li
9aaf516546 bcache: make cutoff_writeback and cutoff_writeback_sync tunable
Currently the cutoff writeback and cutoff writeback sync thresholds are
defined by CUTOFF_WRITEBACK (40) and CUTOFF_WRITEBACK_SYNC (70) as
static values. Most of time these they work fine, but when people want
to do research on bcache writeback mode performance tuning, there is no
chance to modify the soft and hard cutoff writeback values.

This patch introduces two module parameters bch_cutoff_writeback_sync
and bch_cutoff_writeback which permit people to tune the values when
loading bcache.ko. If they are not specified by module loading, current
values CUTOFF_WRITEBACK_SYNC and CUTOFF_WRITEBACK will be used as
default and nothing changes.

When people want to tune this two values,
- cutoff_writeback can be set in range [1, 70]
- cutoff_writeback_sync can be set in range [1, 90]
- cutoff_writeback always <= cutoff_writeback_sync

The default values are strongly recommended to most of users for most of
workloads. Anyway, if people wants to take their own risk to do research
on new writeback cutoff tuning for their own workload, now they can make
it.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li
009673d02f bcache: add MODULE_DESCRIPTION information
This patch moves MODULE_AUTHOR and MODULE_LICENSE to end of super.c, and
add MODULE_DESCRIPTION("Bcache: a Linux block layer cache").

This is preparation for adding module parameters.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li
7a671d8ef8 bcache: option to automatically run gc thread after writeback
The option gc_after_writeback is disabled by default, because garbage
collection will discard SSD data which drops cached data.

Echo 1 into /sys/fs/bcache/<UUID>/internal/gc_after_writeback will
enable this option, which wakes up gc thread when writeback accomplished
and all cached data is clean.

This option is helpful for people who cares writing performance more. In
heavy writing workload, all cached data can be clean only happens when
writeback thread cleans all cached data in I/O idle time. In such
situation a following gc running may help to shrink bcache B+ tree and
discard more clean data, which may be helpful for future writing
requests.

If you are not sure whether this is helpful for your own workload,
please leave it as disabled by default.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Coly Li
cb07ad6368 bcache: introduce force_wake_up_gc()
Garbage collection thread starts to work when c->sectors_to_gc is
negative value, otherwise nothing will happen even the gc thread is
woken up by wake_up_gc().

force_wake_up_gc() sets c->sectors_to_gc to -1 before calling
wake_up_gc(), then gc thread may have chance to run if no one else sets
c->sectors_to_gc to a positive value before gc_should_run().

This routine can be called where the gc thread is woken up and required
to run in force.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang
f383ae300c bcache: cannot set writeback_running via sysfs if no writeback kthread created
"echo 1 > writeback_running" marks writeback_running even if no
writeback kthread created as "d_strtoul(writeback_running)" will simply
set dc-> writeback_running without checking the existence of
dc->writeback_thread.

Add check for setting writeback_running via sysfs: if no writeback
kthread available, reject setting to 1.

v2 -> v3:
  * Make message on wrong assignment more clear.
  * Print name of bcache device instead of name of backing device.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang
79b791466e bcache: do not mark writeback_running too early
A fresh backing device is not attached to any cache_set, and
has no writeback kthread created until first attached to some
cache_set.

But bch_cached_dev_writeback_init run
"
	dc->writeback_running		= true;
	WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING,
			&dc->disk.flags));
"
for any newly formatted backing devices.

For a fresh standalone backing device, we can get something like
following even if no writeback kthread created:
------------------------
/sys/block/bcache0/bcache# cat writeback_running
1
/sys/block/bcache0/bcache# cat writeback_rate_debug
rate:		512.0k/sec
dirty:		0.0k
target:		0.0k
proportional:	0.0k
integral:	0.0k
change:		0.0k/sec
next io:	-15427384ms

The none ZERO fields are misleading as no alive writeback kthread yet.

Set dc->writeback_running false as no writeback thread created in
bch_cached_dev_writeback_init().

We have writeback thread created and woken up in bch_cached_dev_writeback
_start(). Set dc->writeback_running true before bch_writeback_queue()
called, as a writeback thread will check if dc->writeback_running is true
before writing back dirty data, and hung if false detected.

After the change, we can get the following output for a fresh standalone
backing device:
-----------------------
/sys/block/bcache0/bcache$ cat writeback_running
0
/sys/block/bcache0/bcache# cat writeback_rate_debug
rate:		0.0k/sec
dirty:		0.0k
target:		0.0k
proportional:	0.0k
integral:	0.0k
change:		0.0k/sec
next io:	0ms

v1 -> v2:
  Set dc->writeback_running before bch_writeback_queue() called,

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang
4e361e020e bcache: update comment in sysfs.c
We have struct cached_dev allocated by kzalloc in register_bcache(),
which initializes all the fields of cached_dev with 0s. And commit
ce4c3e19e5 ("bcache: Replace bch_read_string_list() by
__sysfs_match_string()") has remove the string "default".

Update the comment.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00
Shenghui Wang
3db4d0783e bcache: update comment for bch_data_insert
commit 220bb38c21 ("bcache: Break up struct search") introduced
changes to struct search and s->iop. bypass/bio are fields of struct
data_insert_op now. Update the comment.

Signed-off-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-13 08:15:54 -07:00