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path: root/drivers/md/raid5-cache.c
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2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 263 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-28md/raid5: fix 'out of memory' during raid cache recoveryAlexei Naberezhnov
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: b4c625c67362 ("md/r5cache: r5cache recovery: part 1") Signed-off-by: Alexei Naberezhnov <anaberezhnov@fb.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2018-10-10md: remove redundant code that is no longer reachableColin Ian King
And earlier commit removed the error label to two statements that are now never reachable. Since this code is now dead code, remove it. Detected by CoverityScan, CID#1462409 ("Structurally dead code") Fixes: d5d885fd514f ("md: introduce new personality funciton start()") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Shaohua Li <shli@fb.com>
2018-08-18Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input Pull input updates from Dmitry Torokhov: - a new driver for Rohm BU21029 touch controller - new bitmap APIs: bitmap_alloc, bitmap_zalloc and bitmap_free - updates to Atmel, eeti. pxrc and iforce drivers - assorted driver cleanups and fixes. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (57 commits) MAINTAINERS: Add PhoenixRC Flight Controller Adapter Input: do not use WARN() in input_alloc_absinfo() Input: mark expected switch fall-throughs Input: raydium_i2c_ts - use true and false for boolean values Input: evdev - switch to bitmap API Input: gpio-keys - switch to bitmap_zalloc() Input: elan_i2c_smbus - cast sizeof to int for comparison bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free() md: Avoid namespace collision with bitmap API dm: Avoid namespace collision with bitmap API Input: pm8941-pwrkey - add resin entry Input: pm8941-pwrkey - abstract register offsets and event code Input: iforce - reorganize joystick configuration lists Input: atmel_mxt_ts - move completion to after config crc is updated Input: atmel_mxt_ts - don't report zero pressure from T9 Input: atmel_mxt_ts - zero terminate config firmware file Input: atmel_mxt_ts - refactor config update code to add context struct Input: atmel_mxt_ts - config CRC may start at T71 Input: atmel_mxt_ts - remove unnecessary debug on ENOMEM Input: atmel_mxt_ts - remove duplicate setup of ABS_MT_PRESSURE ...
2018-08-01md: Avoid namespace collision with bitmap APIAndy Shevchenko
bitmap API (include/linux/bitmap.h) has 'bitmap' prefix for its methods. On the other hand MD bitmap API is special case. Adding 'md' prefix to it to avoid name space collision. No functional changes intended. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Shaohua Li <shli@kernel.org> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2018-07-05md/r5cache: remove redundant pointer bioColin Ian King
Pointer bio is being assigned but is never used hence it is redundant and can be removed. Cleans up clang warning: warning: variable 'bio' set but not used [-Wunused-but-set-variable] Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Shaohua Li <shli@fb.com>
2018-05-30md: convert to bioset_init()/mempool_init()Kent Overstreet
Convert md to embedded bio sets. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-15raid5-ppl: PPL support for disks with write-back cache enabledTomasz Majchrzak
In order to provide data consistency with PPL for disks with write-back cache enabled all data has to be flushed to disks before next PPL entry. The disks to be flushed are marked in the bitmap. It's modified under a mutex and it's only read after PPL io unit is submitted. A limitation of 64 disks in the array has been introduced to keep data structures and implementation simple. RAID5 arrays with so many disks are not likely due to high risk of multiple disks failure. Such restriction should not be a real life limitation. With write-back cache disabled next PPL entry is submitted when data write for current one completes. Data flush defers next log submission so trigger it when there are no stripes for handling found. As PPL assures all data is flushed to disk at request completion, just acknowledge flush request when PPL is enabled. Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com> Signed-off-by: Shaohua Li <sh.li@alibaba-inc.com>
2017-12-20md/r5cache: print more info of log recoverySong Liu
Log recovery is critical for raid5 journal/cache. Printing information about each recovery by default will help the system admin monitor the status of the array. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-12-11md: introduce new personality funciton start()Song Liu
In do_md_run(), md threads should not wake up until the array is fully initialized in md_run(). However, in raid5_run(), raid5-cache may wake up mddev->thread to flush stripes that need to be written back. This design doesn't break badly right now. But it could lead to bad bug in the future. This patch tries to resolve this problem by splitting start up work into two personality functions, run() and start(). Tasks that do not require the md threads should go into run(), while task that require the md threads go into start(). r5l_load_log() is moved to raid5_start(), so it is not called until the md threads are started in do_md_run(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-12-01md/r5cache: move mddev_lock() out of r5c_journal_mode_set()Song Liu
r5c_journal_mode_set() is called by r5c_journal_mode_store() and raid_ctr() in dm-raid. We don't need mddev_lock() when calling from raid_ctr(). This patch fixes this by moves the mddev_lock() to r5c_journal_mode_store(). Cc: stable@vger.kernel.org (v4.13+) Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-11-01md: use lockdep_assert_heldShaohua Li
lockdep_assert_held is a better way to assert lock held, and it works for UP. Signed-off-by: Shaohua Li <shli@fb.com>
2017-11-01md: remove special meaning of ->quiesce(.., 2)NeilBrown
The '2' argument means "wake up anything that is waiting". This is an inelegant part of the design and was added to help support management of suspend_lo/suspend_hi setting. Now that suspend_lo/hi is managed in mddev_suspend/resume, that need is gone. These is still a couple of places where we call 'quiesce' with an argument of '2', but they can safely be changed to call ->quiesce(.., 1); ->quiesce(.., 0) which achieve the same result at the small cost of pausing IO briefly. This removes a small "optimization" from suspend_{hi,lo}_store, but it isn't clear that optimization served a useful purpose. The code now is a lot clearer. Suggested-by: Shaohua Li <shli@kernel.org> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-11-01md: always hold reconfig_mutex when calling mddev_suspend()NeilBrown
Most often mddev_suspend() is called with reconfig_mutex held. Make this a requirement in preparation a subsequent patch. Also require reconfig_mutex to be held for mddev_resume(), partly for symmetry and partly to guarantee no races with incr/decr of mddev->suspend. Taking the mutex in r5c_disable_writeback_async() is a little tricky as this is called from a work queue via log->disable_writeback_work, and flush_work() is called on that while holding ->reconfig_mutex. If the work item hasn't run before flush_work() is called, the work function will not be able to get the mutex. So we use mddev_trylock() inside the wait_event() call, and have that abort when conf->log is set to NULL, which happens before flush_work() is called. We wait in mddev->sb_wait and ensure this is woken when any of the conditions change. This requires waking mddev->sb_wait in mddev_unlock(). This is only like to trigger extra wake_ups of threads that needn't be woken when metadata is being written, and that doesn't happen often enough that the cost would be noticeable. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-10-16md: rename some drivers/md/ files to have an "md-" prefixMike Snitzer
Motivated by the desire to illiminate the imprecise nature of DM-specific patches being unnecessarily sent to both the MD maintainer and mailing-list. Which is born out of the fact that DM files also reside in drivers/md/ Now all MD-specific files in drivers/md/ start with either "raid" or "md-" and the MAINTAINERS file has been updated accordingly. Shaohua: don't change module name Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-09-07Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds
Pull MD updates from Shaohua Li: "This update mainly fixes bugs: - Make raid5 ppl support several ppl from Pawel - Several raid5-cache bug fixes from Song - Bitmap fixes from Neil and Me - One raid1/10 regression fix since 4.12 from Me - Other small fixes and cleanup" * tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: md/bitmap: disable bitmap_resize for file-backed bitmaps. raid5-ppl: Recovery support for multiple partial parity logs md: Runtime support for multiple ppls md/raid0: attach correct cgroup info in bio lib/raid6: align AVX512 constants to 512 bits, not bytes raid5: remove raid5_build_block md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_show md: replace seq_release_private with seq_release md: notify about new spare disk in the container md/raid1/10: reset bio allocated from mempool md/raid5: release/flush io in raid5_do_work() md/bitmap: copy correct data for bitmap super
2017-09-07Merge branch 'for-4.14/block' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer updates from Jens Axboe: "This is the first pull request for 4.14, containing most of the code changes. It's a quiet series this round, which I think we needed after the churn of the last few series. This contains: - Fix for a registration race in loop, from Anton Volkov. - Overflow complaint fix from Arnd for DAC960. - Series of drbd changes from the usual suspects. - Conversion of the stec/skd driver to blk-mq. From Bart. - A few BFQ improvements/fixes from Paolo. - CFQ improvement from Ritesh, allowing idling for group idle. - A few fixes found by Dan's smatch, courtesy of Dan. - A warning fixup for a race between changing the IO scheduler and device remova. From David Jeffery. - A few nbd fixes from Josef. - Support for cgroup info in blktrace, from Shaohua. - Also from Shaohua, new features in the null_blk driver to allow it to actually hold data, among other things. - Various corner cases and error handling fixes from Weiping Zhang. - Improvements to the IO stats tracking for blk-mq from me. Can drastically improve performance for fast devices and/or big machines. - Series from Christoph removing bi_bdev as being needed for IO submission, in preparation for nvme multipathing code. - Series from Bart, including various cleanups and fixes for switch fall through case complaints" * 'for-4.14/block' of git://git.kernel.dk/linux-block: (162 commits) kernfs: checking for IS_ERR() instead of NULL drbd: remove BIOSET_NEED_RESCUER flag from drbd_{md_,}io_bio_set drbd: Fix allyesconfig build, fix recent commit drbd: switch from kmalloc() to kmalloc_array() drbd: abort drbd_start_resync if there is no connection drbd: move global variables to drbd namespace and make some static drbd: rename "usermode_helper" to "drbd_usermode_helper" drbd: fix race between handshake and admin disconnect/down drbd: fix potential deadlock when trying to detach during handshake drbd: A single dot should be put into a sequence. drbd: fix rmmod cleanup, remove _all_ debugfs entries drbd: Use setup_timer() instead of init_timer() to simplify the code. drbd: fix potential get_ldev/put_ldev refcount imbalance during attach drbd: new disk-option disable-write-same drbd: Fix resource role for newly created resources in events2 drbd: mark symbols static where possible drbd: Send P_NEG_ACK upon write error in protocol != C drbd: add explicit plugging when submitting batches drbd: change list_for_each_safe to while(list_first_entry_or_null) drbd: introduce drbd_recv_header_maybe_unplug ...
2017-08-25md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_showSong Liu
In r5c_journal_mode_show(), it is necessary to call mddev_lock() before accessing conf and conf->log. Otherwise, the conf->log may change (and become NULL). Signed-off-by: Song Liu <songliubraving@fb.com> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-08-23block: replace bi_bdev with a gendisk pointer and partitions indexChristoph Hellwig
This way we don't need a block_device structure to submit I/O. The block_device has different life time rules from the gendisk and request_queue and is usually only available when the block device node is open. Other callers need to explicitly create one (e.g. the lightnvm passthrough code, or the new nvme multipathing code). For the actual I/O path all that we need is the gendisk, which exists once per block device. But given that the block layer also does partition remapping we additionally need a partition index, which is used for said remapping in generic_make_request. Note that all the block drivers generally want request_queue or sometimes the gendisk, so this removes a layer of indirection all over the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-08md/r5cache: fix io_unit handling in r5l_log_endio()Song Liu
In r5l_log_endio(), once log->io_list_lock is released, the io unit may be accessed (or even freed) by other threads. Current code doesn't handle the io_unit properly, which leads to potential race conditions. This patch solves this race condition by: 1. Add a pending_stripe count flush_payload. Multiple flush_payloads are counted as only one pending_stripe. Flag has_flush_payload is added to show whether the io unit has flush_payload; 2. In r5l_log_endio(), check flags has_null_flush and has_flush_payload with log->io_list_lock held. After the lock is released, this IO unit is only accessed when we know the pending_stripe counter cannot be zeroed by other threads. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-08-08md/r5cache: call mddev_lock/unlock() in r5c_journal_mode_setSong Liu
In r5c_journal_mode_set(), it is necessary to call mddev_lock() before accessing conf and conf->log. Otherwise, the conf->log may change (and become NULL). Shaohua: fix unlock in failure cases Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-06-18blk: replace bioset_create_nobvec() with a flags arg to bioset_create()NeilBrown
"flags" arguments are often seen as good API design as they allow easy extensibility. bioset_create_nobvec() is implemented internally as a variation in flags passed to __bioset_create(). To support future extension, make the internal structure part of the API. i.e. add a 'flags' argument to bioset_create() and discard bioset_create_nobvec(). Note that the bio_split allocations in drivers/md/raid* do not need the bvec mempool - they should have used bioset_create_nobvec(). Suggested-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-12Merge tag 'v4.12-rc5' into for-4.13/blockJens Axboe
We've already got a few conflicts and upcoming work depends on some of the changes that have gone into mainline as regression fixes for this series. Pull in 4.12-rc5 to resolve these conflicts and make it easier on down stream trees to continue working on 4.13 changes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-09block: switch bios to blk_status_tChristoph Hellwig
Replace bi_error with a new bi_status to allow for a clear conversion. Note that device mapper overloaded bi_error with a private value, which we'll have to keep arround at least for now and thus propagate to a proper blk_status_t value. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-05-31md: Make flush bios explicitely syncJan Kara
Commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...} definitions. generic_make_request_checks() however strips REQ_FUA and REQ_PREFLUSH flags from a bio when the storage doesn't report volatile write cache and thus write effectively becomes asynchronous which can lead to performance regressions Fix the problem by making sure all bios which are synchronous are properly marked with REQ_SYNC. CC: linux-raid@vger.kernel.org CC: Shaohua Li <shli@kernel.org> Fixes: b685d3d65ac791406e0dfd8779cc9b3707fea5a3 CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Shaohua Li <shli@fb.com>
2017-05-11md/r5cache: handle sync with data in write back cacheSong Liu
Currently, sync of raid456 array cannot make progress when hitting data in writeback r5cache. This patch fixes this issue by flushing cached data of the stripe before processing the sync request. This is achived by: 1. In handle_stripe(), do not set STRIPE_SYNCING if the stripe is in write back cache; 2. In r5c_try_caching_write(), handle the stripe in sync with write through; 3. In do_release_stripe(), make stripe in sync write out and send it to the state machine. Shaohua: explictly set STRIPE_HANDLE after write out completed Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-05-11md/r5cache: gracefully handle journal device errors for writeback modeSong Liu
For the raid456 with writeback cache, when journal device failed during normal operation, it is still possible to persist all data, as all pending data is still in stripe cache. However, it is necessary to handle journal failure gracefully. During journal failures, the following logic handles the graceful shutdown of journal: 1. raid5_error() marks the device as Faulty and schedules async work log->disable_writeback_work; 2. In disable_writeback_work (r5c_disable_writeback_async), the mddev is suspended, set to write through, and then resumed. mddev_suspend() flushes all cached stripes; 3. All cached stripes need to be flushed carefully to the RAID array. This patch fixes issues within the process above: 1. In r5c_update_on_rdev_error() schedule disable_writeback_work for journal failures; 2. In r5c_disable_writeback_async(), wait for MD_SB_CHANGE_PENDING, since raid5_error() updates superblock. 3. In handle_stripe(), allow stripes with data in journal (s.injournal > 0) to make progress during log_failed; 4. In delay_towrite(), if log failed only process data in the cache (skip new writes in dev->towrite); 5. In __get_priority_stripe(), process loprio_list during journal device failures. 6. In raid5_remove_disk(), wait for all cached stripes are flushed before calling log_exit(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-05-10md/raid5-cache: in r5l_do_submit_io(), submit io->split_bio firstSong Liu
In r5l_do_submit_io(), it is necessary to check io->split_bio before submit io->current_bio. This is because, endio of current_bio may free the whole IO unit, and thus change io->split_bio. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-05-03Merge tag 'for-4.12/dm-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mike Snitzer: - A major update for DM cache that reduces the latency for deciding whether blocks should migrate to/from the cache. The bio-prison-v2 interface supports this improvement by enabling direct dispatch of work to workqueues rather than having to delay the actual work dispatch to the DM cache core. So the dm-cache policies are much more nimble by being able to drive IO as they see fit. One immediate benefit from the improved latency is a cache that should be much more adaptive to changing workloads. - Add a new DM integrity target that emulates a block device that has additional per-sector tags that can be used for storing integrity information. - Add a new authenticated encryption feature to the DM crypt target that builds on the capabilities provided by the DM integrity target. - Add MD interface for switching the raid4/5/6 journal mode and update the DM raid target to use it to enable aid4/5/6 journal write-back support. - Switch the DM verity target over to using the asynchronous hash crypto API (this helps work better with architectures that have access to off-CPU algorithm providers, which should reduce CPU utilization). - Various request-based DM and DM multipath fixes and improvements from Bart and Christoph. - A DM thinp target fix for a bio structure leak that occurs for each discard IFF discard passdown is enabled. - A fix for a possible deadlock in DM bufio and a fix to re-check the new buffer allocation watermark in the face of competing admin changes to the 'max_cache_size_bytes' tunable. - A couple DM core cleanups. * tag 'for-4.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (50 commits) dm bufio: check new buffer allocation watermark every 30 seconds dm bufio: avoid a possible ABBA deadlock dm mpath: make it easier to detect unintended I/O request flushes dm mpath: cleanup QUEUE_IF_NO_PATH bit manipulation by introducing assign_bit() dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH dm: introduce enum dm_queue_mode to cleanup related code dm mpath: verify __pg_init_all_paths locking assumptions at runtime dm: verify suspend_locking assumptions at runtime dm block manager: remove an unused argument from dm_block_manager_create() dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue() dm mpath: delay requeuing while path initialization is in progress dm mpath: avoid that path removal can trigger an infinite loop dm mpath: split and rename activate_path() to prepare for its expanded use dm ioctl: prevent stack leak in dm ioctl call dm integrity: use previously calculated log2 of sectors_per_block dm integrity: use hex2bin instead of open-coded variant dm crypt: replace custom implementation of hex2bin() dm crypt: remove obsolete references to per-CPU state dm verity: switch to using asynchronous hash crypto API dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues ...
2017-03-27md: add raid4/5/6 journal mode switching APIHeinz Mauelshagen
Commit 2ded370373a4 ("md/r5cache: State machine for raid5-cache write back mode") added support for "write-back" caching on the raid journal device. In order to allow the dm-raid target to switch between the available "write-through" and "write-back" modes, provide a new r5c_journal_mode_set() API. Use the new API in existing r5c_journal_mode_store() Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Acked-by: Shaohua Li <shli@fb.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-03-25md/raid5-cache: fix payload endianness problem in raid5-cacheJason Yan
The payload->header.type and payload->size are little-endian, so just convert them to the right byte order. Signed-off-by: Jason Yan <yanaijie@huawei.com> Cc: <stable@vger.kernel.org> #v4.10+ Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-22md/raid5: use bio_inc_remaining() instead of repurposing bi_phys_segments as ↵NeilBrown
a counter md/raid5 needs to keep track of how many stripe_heads are processing a bio so that it can delay calling bio_endio() until all stripe_heads have completed. It currently uses 16 bits of ->bi_phys_segments for this purpose. 16 bits is only enough for 256M requests, and it is possible for a single bio to be larger than this, which causes problems. Also, the bio struct contains a larger counter, __bi_remaining, which has a purpose very similar to the purpose of our counter. So stop using ->bi_phys_segments, and instead use __bi_remaining. This means we don't need to initialize the counter, as our caller initializes it to '1'. It also means we can call bio_endio() directly as it tests this counter internally. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-22md/raid5: call bio_endio() directly rather than queueing for later.NeilBrown
We currently gather bios that need to be returned into a bio_list and call bio_endio() on them all together. The original reason for this was to avoid making the calls while holding a spinlock. Locking has changed a lot since then, and that reason is no longer valid. So discard return_io() and various return_bi lists, and just call bio_endio() directly as needed. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-22md/raid5: use md_write_start to count stripes, not biosNeilBrown
We use md_write_start() to increase the count of pending writes, and md_write_end() to decrement the count. We currently count bios submitted to md/raid5. Change it count stripe_heads that a WRITE bio has been attached to. So now, raid5_make_request() calls md_write_start() and then md_write_end() to keep the count elevated during the setup of the request. add_stripe_bio() calls md_write_start() for each stripe_head, and the completion routines always call md_write_end(), instead of only calling it when raid5_dec_bi_active_stripes() returns 0. make_discard_request also calls md_write_start/end(). The parallel between md_write_{start,end} and use of bi_phys_segments can be seen in that: Whenever we set bi_phys_segments to 1, we now call md_write_start. Whenever we increment it on non-read requests with raid5_inc_bi_active_stripes(), we now call md_write_start(). Whenever we decrement bi_phys_segments on non-read requsts with raid5_dec_bi_active_stripes(), we now call md_write_end(). This reduces our dependence on keeping a per-bio count of active stripes in bi_phys_segments. md_write_inc() is added which parallels md_write_start(), but requires that a write has already been started, and is certain never to sleep. This can be used inside a spinlocked region when adding to a write request. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-16md/r5cache: generate R5LOG_PAYLOAD_FLUSHSong Liu
In r5c_finish_stripe_write_out(), R5LOG_PAYLOAD_FLUSH is append to log->current_io. Appending R5LOG_PAYLOAD_FLUSH in quiesce needs extra writes to journal. To simplify the logic, we just skip R5LOG_PAYLOAD_FLUSH in quiesce. Even R5LOG_PAYLOAD_FLUSH supports multiple stripes per payload. However, current implementation is one stripe per R5LOG_PAYLOAD_FLUSH, which is simpler. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-16md/r5cache: handle R5LOG_PAYLOAD_FLUSH in recoverySong Liu
This patch adds handling of R5LOG_PAYLOAD_FLUSH in journal recovery. Next patch will add logic that generate R5LOG_PAYLOAD_FLUSH on flush finish. When R5LOG_PAYLOAD_FLUSH is seen in recovery, pending data and parity will be dropped from recovery. This will reduce the number of stripes to replay, and thus accelerate the recovery process. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-16raid5: separate header for log functionsArtur Paszkiewicz
Move raid5-cache declarations from raid5.h to raid5-log.h, add inline wrappers for functions which will be shared with ppl and use them in raid5 core instead of direct calls to raid5-cache. Remove unused parameter from r5c_cache_data(), move two duplicated pr_debug() calls to r5l_init_log(). Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-16md/r5cache: improve recovery with read ahead page poolSong Liu
In r5cache recovery, the journal device is scanned page by page. Currently, we use sync_page_io() to read journal device. This is not efficient when we have to recovery many stripes from the journal. To improve the speed of recovery, this patch introduces a read ahead page pool (ra_pool) to recovery_ctx. With ra_pool, multiple consecutive pages are read in one IO. Then the recovery code read the journal from ra_pool. With ra_pool, r5l_recovery_ctx has become much bigger. Therefore, r5l_recovery_log() is refactored so r5l_recovery_ctx is not using stack space. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-03-16md/raid5-cache: bump flush stripe batch sizeShaohua Li
Bump the flush stripe batch size to 2048. For my 12 disks raid array, the stripes takes: 12 * 4k * 2048 = 96MB This is still quite small. A hardware raid card generally has 1GB size, which we suggest the raid5-cache has similar cache size. The advantage of a big batch size is we can dispatch a lot of IO in the same time, then we can do some scheduling to make better IO pattern. Last patch prioritizes stripes, so we don't worry about a big flush stripe batch will starve normal stripes. Signed-off-by: Shaohua Li <shli@fb.com>
2017-02-13md/raid5-cache: exclude reclaiming stripes in reclaim checkShaohua Li
stripes which are being reclaimed are still accounted into cached stripes. The reclaim takes time. r5c_do_reclaim isn't aware of the stripes and does unnecessary stripe reclaim. In practice, I saw one stripe is reclaimed one time. This will cause bad IO pattern. Fixing this by excluding the reclaing stripes in the check. Cc: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-02-13md/raid5-cache: stripe reclaim only counts valid stripesShaohua Li
When log space is tight, we try to reclaim stripes from log head. There are stripes which can't be reclaimed right now if some conditions are met. We skip such stripes but accidentally count them, which might cause no stripes are claimed. Fixing this by only counting valid stripes. Cc: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-02-13md/r5cache: improve journal device efficiencySong Liu
It is important to be able to flush all stripes in raid5-cache. Therefore, we need reserve some space on the journal device for these flushes. If flush operation includes pending writes to the stripe, we need to reserve (conf->raid_disk + 1) pages per stripe for the flush out. This reduces the efficiency of journal space. If we exclude these pending writes from flush operation, we only need (conf->max_degraded + 1) pages per stripe. With this patch, when log space is critical (R5C_LOG_CRITICAL=1), pending writes will be excluded from stripe flush out. Therefore, we can reduce reserved space for flush out and thus improve journal device efficiency. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-02-13md/r5cache: enable chunk_aligned_read with write back cacheSong Liu
Chunk aligned read significantly reduces CPU usage of raid456. However, it is not safe to fully bypass the write back cache. This patch enables chunk aligned read with write back cache. For chunk aligned read, we track stripes in write back cache at a bigger granularity, "big_stripe". Each chunk may contain more than one stripe (for example, a 256kB chunk contains 64 4kB-page, so this chunk contain 64 stripes). For chunk_aligned_read, these stripes are grouped into one big_stripe, so we only need one lookup for the whole chunk. For each big_stripe, struct big_stripe_info tracks how many stripes of this big_stripe are in the write back cache. We count how many stripes of this big_stripe are in the write back cache. These counters are tracked in a radix tree (big_stripe_tree). r5c_tree_index() is used to calculate keys for the radix tree. chunk_aligned_read() calls r5c_big_stripe_cached() to look up big_stripe of each chunk in the tree. If this big_stripe is in the tree, chunk_aligned_read() aborts. This look up is protected by rcu_read_lock(). It is necessary to remember whether a stripe is counted in big_stripe_tree. Instead of adding new flag, we reuses existing flags: STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE. If either of these two flags are set, the stripe is counted in big_stripe_tree. This requires moving set_bit(STRIPE_R5C_PARTIAL_STRIPE) to r5c_try_caching_write(); and moving clear_bit of STRIPE_R5C_PARTIAL_STRIPE and STRIPE_R5C_FULL_STRIPE to r5c_finish_stripe_write_out(). Signed-off-by: Song Liu <songliubraving@fb.com> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24md/r5cache: disable write back for degraded arraySong Liu
write-back cache in degraded mode introduces corner cases to the array. Although we try to cover all these corner cases, it is safer to just disable write-back cache when the array is in degraded mode. In this patch, we disable writeback cache for degraded mode: 1. On device failure, if the array enters degraded mode, raid5_error() will submit async job r5c_disable_writeback_async to disable writeback; 2. In r5c_journal_mode_store(), it is invalid to enable writeback in degraded mode; 3. In r5c_try_caching_write(), stripes with s->failed>0 will be handled in write-through mode. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24md/r5cache: flush data only stripes in r5l_recovery_log()Song Liu
For safer operation, all arrays start in write-through mode, which has been better tested and is more mature. And actually the write-through/write-mode isn't persistent after array restarted, so we always start array in write-through mode. However, if recovery found data-only stripes before the shutdown (from previous write-back mode), it is not safe to start the array in write-through mode, as write-through mode can not handle stripes with data in write-back cache. To solve this problem, we flush all data-only stripes in r5l_recovery_log(). When r5l_recovery_log() returns, the array starts with empty cache in write-through mode. This logic is implemented in r5c_recovery_flush_data_only_stripes(): 1. enable write back cache 2. flush all stripes 3. wake up conf->mddev->thread 4. wait for all stripes get flushed (reuse wait_for_quiescent) 5. disable write back cache The wait in 4 will be waked up in release_inactive_stripe_list() when conf->active_stripes reaches 0. It is safe to wake up mddev->thread here because all the resource required for the thread has been initialized. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24md/r5cache: read data into orig_page for prexor of cached dataSong Liu
With write back cache, we use orig_page to do prexor. This patch makes sure we read data into orig_page for it. Flag R5_OrigPageUPTDODATE is added to show whether orig_page has the latest data from raid disk. We introduce a helper function uptodate_for_rmw() to simplify the a couple conditions in handle_stripe_dirtying(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-24md/raid5-cache: delete meaningless codeShaohua Li
sector_t is unsigned long, it's never < 0 Reported-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05md/r5cache: fix spelling mistake on "recoverying"Colin Ian King
Trivial fix to spelling mistake "recoverying" to "recovering" in pr_dbg message. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05md/r5cache: assign conf->log before r5l_load_log()Song Liu
r5l_load_log() calls functions that requires a proper conf->log, for example, r5c_is_writeback(). Therefore, we should set conf->log before calling r5l_load_log(). If r5l_load_log() fails, conf->log is set back to NULL. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2017-01-05md/r5cache: simplify handling of sh->log_start in recoverySong Liu
We only need to update sh->log_start at the end of recovery, which is r5c_recovery_rewrite_data_only_stripes(), so it is not necessary to set it before that. In this patch, log_start is removed from r5c_recovery_alloc_stripe(). After updating all sh->log_start, rewrite_data_only_stripes() also updates log->next_checkpoints to the last sh->log_start. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>