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* md: introduce mddev_create/destroy_wb_pool for the change of member deviceGuoqing Jiang2019-06-201-0/+2
| | | | | | | | | | | | | | | | | | | Previously, we called rdev_init_wb to avoid potential data inconsistency when array is created. Now, we need to call the function and create mempool if a device is added or just be flaged as "writemostly". So mddev_create_wb_pool is introduced and called accordingly. And for safety reason, we mark implicit GFP_NOIO allocation scope for create mempool during mddev_suspend/mddev_resume. And mempool should be removed conversely after remove a member device or its's "writemostly" flag, which is done by call mddev_destroy_wb_pool. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Song Liu <songliubraving@fb.com>
* md/raid1: fix potential data inconsistency issue with write behind deviceGuoqing Jiang2019-06-201-0/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For write-behind mode, we think write IO is complete once it has reached all the non-writemostly devices. It works fine for single queue devices. But for multiqueue device, if there are lots of IOs come from upper layer, then the write-behind device could issue those IOs to different queues, depends on the each queue's delay, so there is no guarantee that those IOs can arrive in order. To address the issue, we need to check the collision among write behind IOs, we can only continue without collision, otherwise wait for the completion of previous collisioned IO. And WBCollision is introduced for multiqueue device which is worked under write-behind mode. But this patch doesn't handle below cases which could have the data inconsistency issue as well, these cases will be handled in later patches. 1. modify max_write_behind by write backlog node. 2. add or remove array's bitmap dynamically. 3. the change of member disk. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Song Liu <songliubraving@fb.com>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 47Thomas Gleixner2019-05-241-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 or at your option any later version you should have received a copy of the gnu general public license for example usr src linux copying if not write to the free software foundation inc 675 mass ave cambridge ma 02139 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 20 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.552543146@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* md: batch flush requests.NeilBrown2019-04-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently if many flush requests are submitted to an md device is quick succession, they are serialized and can take a long to process them all. We don't really need to call flush all those times - a single flush call can satisfy all requests submitted before it started. So keep track of when the current flush started and when it finished, allow any pending flush that was requested before the flush started to complete without waiting any more. Test results from Xiao: Test is done on a raid10 device which is created by 4 SSDs. The tool is dbench. 1. The latest linux stable kernel Operation Count AvgLat MaxLat -------------------------------------------------- Deltree 768 10.509 78.305 Flush 2078376 0.013 10.094 Close 21787697 0.019 18.821 LockX 96580 0.007 3.184 Mkdir 384 0.008 0.062 Rename 1255883 0.191 23.534 ReadX 46495589 0.020 14.230 WriteX 14790591 7.123 60.706 Unlink 5989118 0.440 54.551 UnlockX 96580 0.005 2.736 FIND_FIRST 10393845 0.042 12.079 SET_FILE_INFORMATION 2415558 0.129 10.088 QUERY_FILE_INFORMATION 4711725 0.005 8.462 QUERY_PATH_INFORMATION 26883327 0.032 21.715 QUERY_FS_INFORMATION 4929409 0.010 8.238 NTCreateX 29660080 0.100 53.268 Throughput 1034.88 MB/sec (sync open) 128 clients 128 procs max_latency=60.712 ms 2. With patch1 "Revert "MD: fix lock contention for flush bios"" Operation Count AvgLat MaxLat -------------------------------------------------- Deltree 256 8.326 36.761 Flush 693291 3.974 180.269 Close 7266404 0.009 36.929 LockX 32160 0.006 0.840 Mkdir 128 0.008 0.021 Rename 418755 0.063 29.945 ReadX 15498708 0.007 7.216 WriteX 4932310 22.482 267.928 Unlink 1997557 0.109 47.553 UnlockX 32160 0.004 1.110 FIND_FIRST 3465791 0.036 7.320 SET_FILE_INFORMATION 805825 0.015 1.561 QUERY_FILE_INFORMATION 1570950 0.005 2.403 QUERY_PATH_INFORMATION 8965483 0.013 14.277 QUERY_FS_INFORMATION 1643626 0.009 3.314 NTCreateX 9892174 0.061 41.278 Throughput 345.009 MB/sec (sync open) 128 clients 128 procs max_latency=267.939 m 3. With patch1 and patch2 Operation Count AvgLat MaxLat -------------------------------------------------- Deltree 768 9.570 54.588 Flush 2061354 0.666 15.102 Close 21604811 0.012 25.697 LockX 95770 0.007 1.424 Mkdir 384 0.008 0.053 Rename 1245411 0.096 12.263 ReadX 46103198 0.011 12.116 WriteX 14667988 7.375 60.069 Unlink 5938936 0.173 30.905 UnlockX 95770 0.005 4.147 FIND_FIRST 10306407 0.041 11.715 SET_FILE_INFORMATION 2395987 0.048 7.640 QUERY_FILE_INFORMATION 4672371 0.005 9.291 QUERY_PATH_INFORMATION 26656735 0.018 19.719 QUERY_FS_INFORMATION 4887940 0.010 7.654 NTCreateX 29410811 0.059 28.551 Throughput 1026.21 MB/sec (sync open) 128 clients 128 procs max_latency=60.075 ms Cc: <stable@vger.kernel.org> # v4.19+ Tested-by: Xiao Ni <xni@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Revert "MD: fix lock contention for flush bios"NeilBrown2019-04-011-15/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 5a409b4f56d50b212334f338cb8465d65550cd85. This patch has two problems. 1/ it make multiple calls to submit_bio() from inside a make_request_fn. The bios thus submitted will be queued on current->bio_list and not submitted immediately. As the bios are allocated from a mempool, this can theoretically result in a deadlock - all the pool of requests could be in various ->bio_list queues and a subsequent mempool_alloc could block waiting for one of them to be released. 2/ It aims to handle a case when there are many concurrent flush requests. It handles this by submitting many requests in parallel - all of which are identical and so most of which do nothing useful. It would be more efficient to just send one lower-level request, but allow that to satisfy multiple upper-level requests. Fixes: 5a409b4f56d5 ("MD: fix lock contention for flush bios") Cc: <stable@vger.kernel.org> # v4.19+ Tested-by: Xiao Ni <xni@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* md-cluster/raid10: support add disk under grow modeGuoqing Jiang2018-10-181-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For clustered raid10 scenario, we need to let all the nodes know about that a new disk is added to the array, and the reshape caused by add new member just need to be happened in one node, but other nodes should know about the change. Since reshape means read data from somewhere (which is already used by array) and write data to unused region. Obviously, it is awful if one node is reading data from address while another node is writing to the same address. Considering we have implemented suspend writes in the resyncing area, so we can just broadcast the reading address to other nodes to avoid the trouble. For master node, it would call reshape_request then update sb during the reshape period. To avoid above trouble, we call resync_info_update to send RESYNC message in reshape_request. Then from slave node's view, it receives two type messages: 1. RESYNCING message Slave node add the address (where master node reading data from) to suspend list. 2. METADATA_UPDATED message Once slave nodes know the reshaping is started in master node, it is time to update reshape position and call start_reshape to follow master node's step. After reshape is done, only reshape position is need to be updated, so the majority task of reshaping is happened on the master node. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md-cluster: show array's status more accurateGuoqing Jiang2018-07-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When resync or recovery is happening in one node, other nodes don't show the appropriate info now. For example, when create an array in master node without "--assume-clean", then assemble the array in slave nodes, you can see "resync=PENDING" when read /proc/mdstat in slave nodes. However, the info is confusing since "PENDING" status is introduced for start array in read-only mode. We introduce RESYNCING_REMOTE flag to indicate that resync thread is running in remote node. The flags is set when node receive RESYNCING msg. And we clear the REMOTE flag in following cases: 1. resync or recover is finished in master node, which means slaves receive msg with both lo and hi are set to 0. 2. node continues resync/recovery in recover_bitmaps. 3. when resync_finish is called. Then we show accurate information in status_resync by check REMOTE flags and with other conditions. Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds2018-06-091-7/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull MD updates from Shaohua Li: "A few fixes of MD for this merge window. Mostly bug fixes: - raid5 stripe batch fix from Amy - Read error handling for raid1 FailFast device from Gioh - raid10 recovery NULL pointer dereference fix from Guoqing - Support write hint for raid5 stripe cache from Mariusz - Fixes for device hot add/remove from Neil and Yufen - Improve flush bio scalability from Xiao" * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/md: MD: fix lock contention for flush bios md/raid5: Assigning NULL to sh->batch_head before testing bit R5_Overlap of a stripe md/raid1: add error handling of read error from FailFast device md: fix NULL dereference of mddev->pers in remove_and_add_spares() raid5: copy write hint from origin bio to stripe md: fix two problems with setting the "re-add" device state. raid10: check bio in r10buf_pool_free to void NULL pointer dereference md: fix an error code format and remove unsed bio_sector
| * MD: fix lock contention for flush biosXiao Ni2018-05-211-7/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a lock contention when there are many processes which send flush bios to md device. eg. Create many lvs on one raid device and mkfs.xfs on each lv. Now it just can handle flush request sequentially. It needs to wait mddev->flush_bio to be NULL, otherwise get mddev->lock. This patch remove mddev->flush_bio and handle flush bio asynchronously. I did a test with command dbench -s 128 -t 300. This is the test result: =================Without the patch============================ Operation Count AvgLat MaxLat -------------------------------------------------- Flush 11165 167.595 5879.560 Close 107469 1.391 2231.094 LockX 384 0.003 0.019 Rename 5944 2.141 1856.001 ReadX 208121 0.003 0.074 WriteX 98259 1925.402 15204.895 Unlink 25198 13.264 3457.268 UnlockX 384 0.001 0.009 FIND_FIRST 47111 0.012 0.076 SET_FILE_INFORMATION 12966 0.007 0.065 QUERY_FILE_INFORMATION 27921 0.004 0.085 QUERY_PATH_INFORMATION 124650 0.005 5.766 QUERY_FS_INFORMATION 22519 0.003 0.053 NTCreateX 141086 4.291 2502.812 Throughput 3.7181 MB/sec (sync open) 128 clients 128 procs max_latency=15204.905 ms =================With the patch============================ Operation Count AvgLat MaxLat -------------------------------------------------- Flush 4500 174.134 406.398 Close 48195 0.060 467.062 LockX 256 0.003 0.029 Rename 2324 0.026 0.360 ReadX 78846 0.004 0.504 WriteX 66832 562.775 1467.037 Unlink 5516 3.665 1141.740 UnlockX 256 0.002 0.019 FIND_FIRST 16428 0.015 0.313 SET_FILE_INFORMATION 6400 0.009 0.520 QUERY_FILE_INFORMATION 17865 0.003 0.089 QUERY_PATH_INFORMATION 47060 0.078 416.299 QUERY_FS_INFORMATION 7024 0.004 0.032 NTCreateX 55921 0.854 1141.452 Throughput 11.744 MB/sec (sync open) 128 clients 128 procs max_latency=1467.041 ms The test is done on raid1 disk with two rotational disks V5: V4 is more complicated than the version with memory pool. So revert to the memory pool version V4: use address of fbio to do hash to choose free flush info. V3: Shaohua suggests mempool is overkill. In v3 it allocs memory during creating raid device and uses a simple bitmap to record which resource is free. Fix a bug from v2. It should set flush_pending to 1 at first. V2: Neil pointed out two problems. One is counting error problem and another is return value when allocat memory fails. 1. counting error problem This isn't safe. It is only safe to call rdev_dec_pending() on rdevs that you previously called atomic_inc(&rdev->nr_pending); If an rdev was added to the list between the start and end of the flush, this will do something bad. Now it doesn't use bio_chain. It uses specified call back function for each flush bio. 2. Returned on IO error when kmalloc fails is wrong. I use mempool suggested by Neil in V2 3. Fixed some places pointed by Guoqing Suggested-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Xiao Ni <xni@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
* | md: convert to bioset_init()/mempool_init()Kent Overstreet2018-05-301-2/+2
|/ | | | | | | Convert md to embedded bio sets. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* md: fix md_write_start() deadlock w/o metadata devicesHeinz Mauelshagen2018-02-181-0/+2
| | | | | | | | | | | | | | | | | If no metadata devices are configured on raid1/4/5/6/10 (e.g. via dm-raid), md_write_start() unconditionally waits for superblocks to be written thus deadlocking. Fix introduces mddev->has_superblocks bool, defines it in md_run() and checks for it in md_write_start() to conditionally avoid waiting. Once on it, check for non-existing superblocks in md_super_write(). Link: https://bugzilla.kernel.org/show_bug.cgi?id=198647 Fixes: cc27b0c78c796 ("md: fix deadlock between mddev_suspend() and md_write_start()") Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Shaohua Li <sh.li@alibaba-inc.com>
* raid5-ppl: PPL support for disks with write-back cache enabledTomasz Majchrzak2018-01-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | 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>
* md: introduce new personality funciton start()Song Liu2017-12-111-0/+8
| | | | | | | | | | | | | | | | | | | 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>
* md: use lockdep_assert_heldShaohua Li2017-11-011-5/+0
| | | | | | | lockdep_assert_held is a better way to assert lock held, and it works for UP. Signed-off-by: Shaohua Li <shli@fb.com>
* md: remove special meaning of ->quiesce(.., 2)NeilBrown2017-11-011-5/+4
| | | | | | | | | | | | | | | | | | | | | 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>
* md: allow metadata update while suspending.NeilBrown2017-11-011-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | There are various deadlocks that can occur when a thread holds reconfig_mutex and calls ->quiesce(mddev, 1). As some write request block waiting for metadata to be updated (e.g. to record device failure), and as the md thread updates the metadata while the reconfig mutex is held, holding the mutex can stop write requests completing, and this prevents ->quiesce(mddev, 1) from completing. ->quiesce() is now usually called from mddev_suspend(), and it is always called with reconfig_mutex held. So at this time it is safe for the thread to update metadata without explicitly taking the lock. So add 2 new flags, one which says the unlocked updates is allowed, and one which ways it is happening. Then allow it while the quiesce completes, and then wait for it to finish. Reported-and-tested-by: Xiao Ni <xni@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: separate request handlingShaohua Li2017-09-271-0/+1
| | | | | | | | | | | | | With commit cc27b0c78c79, pers->make_request could bail out without handling the bio. If that happens, we should retry. The commit fixes md_make_request but not other call sites. Separate the request handling part, so other call sites can use it. Reported-by: Nate Dailey <nate.dailey@stratus.com> Fix: cc27b0c78c79(md: fix deadlock between mddev_suspend() and md_write_start()) Cc: stable@vger.kernel.org Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* Merge tag 'md/4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shli/mdLinus Torvalds2017-09-071-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * md: Runtime support for multiple pplsPawel Baldysiak2017-08-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | Increase PPL area to 1MB and use it as circular buffer to store PPL. The entry with highest generation number is the latest one. If PPL to be written is larger then space left in a buffer, rewind the buffer to the start (don't wrap it). Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
* | block: replace bi_bdev with a gendisk pointer and partitions indexChristoph Hellwig2017-08-231-2/+7
|/ | | | | | | | | | | | | | | | | | | | 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>
* md: raid1-10: move raid1/raid10 common code into raid1-10.cMing Lei2017-07-211-53/+0
| | | | | | | | No function change, just move 'struct resync_pages' and related helpers into raid1-10.c Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: remove 'idx' from 'struct resync_pages'Ming Lei2017-07-211-1/+0
| | | | | | | | | | | | | | | | | | bio_add_page() won't fail for resync bio, and the page index for each bio is same, so remove it. More importantly the 'idx' of 'struct resync_pages' is initialized in mempool allocator function, the current way is wrong since mempool is only responsible for allocation, we can't use that for initialization. Suggested-by: NeilBrown <neilb@suse.com> Reported-by: NeilBrown <neilb@suse.com> Reported-and-tested-by: Patrick <dto@gmx.net> Fixes: f0250618361d(md: raid10: don't use bio's vec table to manage resync pages) Fixes: 98d30c5812c3(md: raid1: don't use bio's vec table to manage resync pages) Cc: stable@vger.kernel.org (4.12+) Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md/bitmap: don't read page from device with Bitmap_syncGuoqing Jiang2017-07-101-1/+3
| | | | | | | | | | | | | | | The device owns Bitmap_sync flag needs recovery to become in sync, and read page from this type device could get stale status. Also add comments for Bitmap_sync bit per the suggestion from Shaohua and Neil. Previous disscussion can be found here: https://marc.info/?t=149760428900004&r=1&w=2 Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: use a separate bio_set for synchronous IO.NeilBrown2017-06-211-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | md devices allocate a bio_set and use it for two distinct purposes. mddev->bio_set is used to clone bios as part of sending upper level requests down to lower level devices, and it is also use for synchronous IO such as superblock and bitmap updates, and for correcting read errors. This multiple usage can lead to deadlocks. It is likely that cloned bios might be queued for write and to be waiting for a metadata update before the write can be permitted. If the cloning exhausted mddev->bio_set, the metadata update may not be able to proceed. This scenario has been seen during heavy testing, with lots of IO and lots of memory pressure. Address this by adding a new bio_set specifically for synchronous IO. All synchronous IO goes directly to the underlying device and is not queued at the md level, so request using entries from the new mddev->sync_set will complete in a timely fashion. Requests that use mddev->bio_set will sometimes need to wait for synchronous IO, but will no longer risk deadlocking that iO. Also: small simplification in mddev_put(): there is no need to wait until the spinlock is released before calling bioset_free(). Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: fix deadlock between mddev_suspend() and md_write_start()NeilBrown2017-06-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | If mddev_suspend() races with md_write_start() we can deadlock with mddev_suspend() waiting for the request that is currently in md_write_start() to complete the ->make_request() call, and md_write_start() waiting for the metadata to be updated to mark the array as 'dirty'. As metadata updates done by md_check_recovery() only happen then the mddev_lock() can be claimed, and as mddev_suspend() is often called with the lock held, these threads wait indefinitely for each other. We fix this by having md_write_start() abort if mddev_suspend() is happening, and ->make_request() aborts if md_write_start() aborted. md_make_request() can detect this abort, decrease the ->active_io count, and wait for mddev_suspend(). Reported-by: Nix <nix@esperi.org.uk> Fix: 68866e425be2(MD: no sync IO while suspended) Cc: stable@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: initialise ->writes_pending in personality modules.NeilBrown2017-06-051-0/+1
| | | | | | | | | | | | | | | | The new per-cpu counter for writes_pending is initialised in md_alloc(), which is not called by dm-raid. So dm-raid fails when md_write_start() is called. Move the initialization to the personality modules that need it. This way it is always initialised when needed, but isn't unnecessarily initialized (requiring memory allocation) when the personality doesn't use writes_pending. Reported-by: Heinz Mauelshagen <heinzm@redhat.com> Fixes: 4ad23a976413 ("MD: use per-cpu counter for writes_pending") Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: don't return -EAGAIN in md_allow_write for external metadata arraysArtur Paszkiewicz2017-05-081-1/+1
| | | | | | | | | | | | | | | | This essentially reverts commit b5470dc5fc18 ("md: resolve external metadata handling deadlock in md_allow_write") with some adjustments. Since commit 6791875e2e53 ("md: make reconfig_mutex optional for writes to md sysfs files.") changing array_state to 'active' does not use mddev_lock() and will not cause a deadlock with md_allow_write(). This revert simplifies userspace tools that write to sysfs attributes like "stripe_cache_size" or "consistency_policy" because it removes the need for special handling for external metadata arrays, checking for EAGAIN and retrying the write. Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
* Merge branch 'md-next' into md-linusShaohua Li2017-05-011-4/+67
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| * md: prepare for managing resync I/O pages in clean wayMing Lei2017-03-241-0/+50
| | | | | | | | | | | | | | | | | | | | | | | | Now resync I/O use bio's bec table to manage pages, this way is very hacky, and may not work any more once multipage bvec is introduced. So introduce helpers and new data structure for managing resync I/O pages more cleanly. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * md: move two macros into md.hMing Lei2017-03-241-0/+5
| | | | | | | | | | | | | | | | Both raid1 and raid10 share common resync block size and page count, so move them into md.h. Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * MD: use per-cpu counter for writes_pendingNeilBrown2017-03-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 'writes_pending' counter is used to determine when the array is stable so that it can be marked in the superblock as "Clean". Consequently it needs to be updated frequently but only checked for zero occasionally. Recent changes to raid5 cause the count to be updated even more often - once per 4K rather than once per bio. This provided justification for making the updates more efficient. So we replace the atomic counter a percpu-refcount. This can be incremented and decremented cheaply most of the time, and can be switched to "atomic" mode when more precise counting is needed. As it is possible for multiple threads to want a precise count, we introduce a "sync_checker" counter to count the number of threads in "set_in_sync()", and only switch the refcount back to percpu mode when that is zero. We need to be careful about races between set_in_sync() setting ->in_sync to 1, and md_write_start() setting it to zero. md_write_start() holds the rcu_read_lock() while checking if the refcount is in percpu mode. If it is, then we know a switch to 'atomic' will not happen until after we call rcu_read_unlock(), in which case set_in_sync() will see the elevated count, and not set in_sync to 1. If it is not in percpu mode, we take the mddev->lock to ensure proper synchronization. It is no longer possible to quickly check if the count is zero, which we previously did to update a timer or to schedule the md_thread. So now we do these every time we decrement that counter, but make sure they are fast. mod_timer() already optimizes the case where the timeout value doesn't actually change. We leverage that further by always rounding off the jiffies to the timeout value. This may delay the marking of 'clean' slightly, but ensure we only perform atomic operation here when absolutely needed. md_wakeup_thread() current always calls wake_up(), even if THREAD_WAKEUP is already set. That too can be optimised to avoid calls to wake_up(). Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * md/raid5: use md_write_start to count stripes, not biosNeilBrown2017-03-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * raid5-ppl: runtime PPL enabling or disablingArtur Paszkiewicz2017-03-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow writing to 'consistency_policy' attribute when the array is active. Add a new function 'change_consistency_policy' to the md_personality operations structure to handle the change in the personality code. Values "ppl" and "resync" are accepted and turn PPL on and off respectively. When enabling PPL its location and size should first be set using 'ppl_sector' and 'ppl_size' attributes and a valid PPL header should be written at this location on each member device. Enabling or disabling PPL is performed under a suspended array. The raid5_reset_stripe_cache function frees the stripe cache and allocates it again in order to allocate or free the ppl_pages for the stripes in the stripe cache. Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * md: superblock changes for PPLArtur Paszkiewicz2017-03-161-0/+8
| | | | | | | | | | | | | | | | | | | | | | Include information about PPL location and size into mdp_superblock_1 and copy it to/from rdev. Because PPL is mutually exclusive with bitmap, put it in place of 'bitmap_offset'. Add a new flag MD_FEATURE_PPL for 'feature_map', analogically to MD_FEATURE_BITMAP_OFFSET. Add MD_HAS_PPL to mddev->flags to indicate that PPL is enabled on an array. Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * md-cluster: use sync way to handle METADATA_UPDATED msgGuoqing Jiang2017-03-161-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, when node received METADATA_UPDATED msg, it just need to wakeup mddev->thread, then md_reload_sb will be called eventually. We taken the asynchronous way to avoid a deadlock issue, the deadlock issue could happen when one node is receiving the METADATA_UPDATED msg (wants reconfig_mutex) and trying to run the path: md_check_recovery -> mddev_trylock(hold reconfig_mutex) -> md_update_sb-metadata_update_start (want EX on token however token is got by the sending node) Since we will support resizing for clustered raid, and we need the metadata update handling to be synchronous so that the initiating node can detect failure, so we need to change the way for handling METADATA_UPDATED msg. But, we obviously need to avoid above deadlock with the sync way. To make this happen, we considered to not hold reconfig_mutex to call md_reload_sb, if some other thread has already taken reconfig_mutex and waiting for the 'token', then process_recvd_msg() can safely call md_reload_sb() without taking the mutex. This is because we can be certain that no other thread will take the mutex, and we also certain that the actions performed by md_reload_sb() won't interfere with anything that the other thread is in the middle of. To make this more concrete, we added a new cinfo->state bit MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD Which is set in lock_token() just before dlm_lock_sync() is called, and cleared just after. As lock_token() is always called with reconfig_mutex() held (the specific case is the resync_info_update which is distinguished well in previous patch), if process_recvd_msg() finds that the new bit is set, then the mutex must be held by some other thread, and it will keep waiting. So process_metadata_update() can call md_reload_sb() if either mddev_trylock() succeeds, or if MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD is set. The tricky bit is what to do if neither of these apply. We need to wait. Fortunately mddev_unlock() always calls wake_up() on mddev->thread->wqueue. So we can get lock_token() to call wake_up() on that when it sets the bit. There are also some related changes inside this commit: 1. remove RELOAD_SB related codes since there are not valid anymore. 2. mddev is added into md_cluster_info then we can get mddev inside lock_token. 3. add new parameter for lock_token to distinguish reconfig_mutex is held or not. And, we need to set MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD in below: 1. set it before unregister thread, otherwise a deadlock could appear if stop a resyncing array. This is because md_unregister_thread(&cinfo->recv_thread) is blocked by recv_daemon -> process_recvd_msg -> process_metadata_update. To resolve the issue, MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD is also need to be set before unregister thread. 2. set it in metadata_update_start to fix another deadlock. a. Node A sends METADATA_UPDATED msg (held Token lock). b. Node B wants to do resync, and is blocked since it can't get Token lock, but MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD is not set since the callchain (md_do_sync -> sync_request -> resync_info_update -> sendmsg -> lock_comm -> lock_token) doesn't hold reconfig_mutex. c. Node B trys to update sb (held reconfig_mutex), but stopped at wait_event() in metadata_update_start since we have set MD_CLUSTER_SEND_LOCK flag in lock_comm (step 2). d. Then Node B receives METADATA_UPDATED msg from A, of course recv_daemon is blocked forever. Since metadata_update_start always calls lock_token with reconfig_mutex, we need to set MD_CLUSTER_HOLDING_MUTEX_FOR_RECVD here as well, and lock_token don't need to set it twice unless lock_token is invoked from lock_comm. Finally, thanks to Neil for his great idea and help! Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* | md: support REQ_OP_WRITE_ZEROESChristoph Hellwig2017-04-081-0/+7
|/ | | | | | | | Copy & paste from the REQ_OP_WRITE_SAME code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
* md: delete dead codeShaohua Li2017-03-091-6/+0
| | | | | | Nobody is using mddev_check_plugged(), so delete the dead code Signed-off-by: Shaohua Li <shli@fb.com>
* md: fast clone bio in bio_clone_mddev()Ming Lei2017-02-151-2/+0
| | | | | | | | | | | | | | | | | | | Firstly bio_clone_mddev() is used in raid normal I/O and isn't in resync I/O path. Secondly all the direct access to bvec table in raid happens on resync I/O except for write behind of raid1, in which we still use bio_clone() for allocating new bvec table. So this patch replaces bio_clone() with bio_clone_fast() in bio_clone_mddev(). Also kill bio_clone_mddev() and call bio_clone_fast() directly, as suggested by Christoph Hellwig. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: disable WRITE SAME if it fails in underlayer disksShaohua Li2017-02-131-0/+7
| | | | | | | | | | | | | | | | This makes md do the same thing as dm for write same IO failure. Please see 7eee4ae(dm: disable WRITE SAME if it fails) for details why we need this. We did a little bit different than dm. Instead of disabling writesame in the first IO error, we disable it till next writesame IO coming after the first IO error. This way we don't need to clone a bio. Also reported here: https://bugzilla.kernel.org/show_bug.cgi?id=118581 Suggested-by: NeilBrown <neilb@suse.com> Acked-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: cleanup mddev flag clear for takeoverShaohua Li2017-01-051-0/+8
| | | | | | | | | | Commit 6995f0b (md: takeover should clear unrelated bits) clear unrelated bits, but it's quite fragile. To avoid error in the future, define a macro for unsupported mddev flags for each raid type and use it to clear unsupported mddev flags. This should be less error-prone. Suggested-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: separate flags for superblock changesShaohua Li2016-12-081-7/+9
| | | | | | | | | | | The mddev->flags are used for different purposes. There are a lot of places we check/change the flags without masking unrelated flags, we could check/change unrelated flags. These usage are most for superblock write, so spearate superblock related flags. This should make the code clearer and also fix real bugs. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: Use REQ_FAILFAST_* on metadata writes where appropriateNeilBrown2016-11-221-1/+20
| | | | | | | | | | | | | | | | | This can only be supported on personalities which ensure that md_error() never causes an array to enter the 'failed' state. i.e. if marking a device Faulty would cause some data to be inaccessible, the device is status is left as non-Faulty. This is true for RAID1 and RAID10. If we get a failure writing metadata but the device doesn't fail, it must be the last device so we re-write without FAILFAST to improve chance of success. We also flag the device as LastDev so that future metadata updates don't waste time on failfast writes. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md/failfast: add failfast flag for md to be used by some personalities.NeilBrown2016-11-221-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch just adds a 'failfast' per-device flag which can be stored in v0.90 or v1.x metadata. The flag is not used yet but the intent is that it can be used for mirrored (raid1/raid10) arrays where low latency is more important than keeping all devices on-line. Setting the flag for a device effectively gives permission for that device to be marked as Faulty and excluded from the array on the first error. The underlying driver will be directed not to retry requests that result in failures. There is a proviso that the device must not be marked faulty if that would cause the array as a whole to fail, it may only be marked Faulty if the array remains functional, but is degraded. Failures on read requests will cause the device to be marked as Faulty immediately so that further reads will avoid that device. No attempt will be made to correct read errors by over-writing with the correct data. It is expected that if transient errors, such as cable unplug, are possible, then something in user-space will revalidate failed devices and re-add them when they appear to be working again. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: define mddev flags, recovery flags and r1bio state bits using enumsNeilBrown2016-11-091-40/+36
| | | | | | | This is less error prone than using individual #defines. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: add bad block support for external metadataTomasz Majchrzak2016-11-071-0/+3
| | | | | | | | | | | | | | | | | | | | | Add new rdev flag which external metadata handler can use to switch on/off bad block support. If new bad block is encountered, notify it via rdev 'unacknowledged_bad_blocks' sysfs file. If bad block has been cleared, notify update to rdev 'bad_blocks' sysfs file. When bad blocks support is being removed, just clear rdev flag. It is not necessary to reset badblocks->shift field. If there are bad blocks cleared or added at the same time, it is ok for those changes to be applied to the structure. The array is in blocked state and the drive which cannot handle bad blocks any more will be removed from the array before it is unlocked. Simplify state_show function by adding a separator at the end of each string and overwrite last separator with new line. Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com> Reviewed-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
* md: changes for MD_STILL_CLOSED flagGuoqing Jiang2016-09-211-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | When stop clustered raid while it is pending on resync, MD_STILL_CLOSED flag could be cleared since udev rule is triggered to open the mddev. So obviously array can't be stopped soon and returns EBUSY. mdadm -Ss md-raid-arrays.rules set MD_STILL_CLOSED md_open() ... ... ... clear MD_STILL_CLOSED do_md_stop We make below changes to resolve this issue: 1. rename MD_STILL_CLOSED to MD_CLOSING since it is set when stop array and it means we are stopping array. 2. let md_open returns early if CLOSING is set, so no other threads will open array if one thread is trying to close it. 3. no need to clear CLOSING bit in md_open because 1 has ensure the bit is cleared, then we also don't need to test CLOSING bit in do_md_stop. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
* Merge branch 'mymd/for-next' into mymd/for-linusShaohua Li2016-07-281-1/+9
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| * md: use seconds granularity for error loggingArnd Bergmann2016-07-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The md code stores the exact time of the last error in the last_read_error variable using a timespec structure. It only ever uses the seconds portion of that though, so we can use a scalar for it. There won't be an overflow in 2038 here, because it already used monotonic time and 32-bit is enough for that, but I've decided to use time64_t for consistency in the conversion. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Shaohua Li <shli@fb.com>
| * md: reduce the number of synchronize_rcu() calls when multiple devices fail.NeilBrown2016-06-131-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Every time a device is removed with ->hot_remove_disk() a synchronize_rcu() call is made which can delay several milliseconds in some case. If lots of devices fail at once - as could happen with a large RAID10 where one set of devices are removed all at once - these delays can add up to be very inconcenient. As failure is not reversible we can check for that first, setting a separate flag if it is found, and then all synchronize_rcu() once for all the flagged devices. Then ->hot_remove_disk() function can skip the synchronize_rcu() step if the flag is set. fix build error(Shaohua) Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
| * md-cluster: fix deadlock issue when add disk to an recoverying arrayGuoqing Jiang2016-06-031-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a disk to an array which is performing recovery is a little complicated, we need to do both reap the sync thread and perform add disk for the case, then it caused deadlock as follows. linux44:~ # ps aux|grep md|grep D root 1822 0.0 0.0 0 0 ? D 16:50 0:00 [md127_resync] root 1848 0.0 0.0 19860 952 pts/0 D+ 16:50 0:00 mdadm --manage /dev/md127 --re-add /dev/vdb linux44:~ # cat /proc/1848/stack [<ffffffff8107afde>] kthread_stop+0x6e/0x120 [<ffffffffa051ddb0>] md_unregister_thread+0x40/0x80 [md_mod] [<ffffffffa0526e45>] md_reap_sync_thread+0x15/0x150 [md_mod] [<ffffffffa05271e0>] action_store+0x260/0x270 [md_mod] [<ffffffffa05206b4>] md_attr_store+0xb4/0x100 [md_mod] [<ffffffff81214a7e>] sysfs_write_file+0xbe/0x140 [<ffffffff811a6b98>] vfs_write+0xb8/0x1e0 [<ffffffff811a75b8>] SyS_write+0x48/0xa0 [<ffffffff8152a5c9>] system_call_fastpath+0x16/0x1b [<00007f068ea1ed30>] 0x7f068ea1ed30 linux44:~ # cat /proc/1822/stack [<ffffffffa05251a6>] md_do_sync+0x846/0xf40 [md_mod] [<ffffffffa052402d>] md_thread+0x16d/0x180 [md_mod] [<ffffffff8107ad94>] kthread+0xb4/0xc0 [<ffffffff8152a518>] ret_from_fork+0x58/0x90 Task1848 Task1822 md_attr_store (held reconfig_mutex by call mddev_lock()) action_store md_reap_sync_thread md_unregister_thread kthread_stop md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_PENDING)) md_check_recovery is triggered by wakeup mddev->thread, but it can't clear MD_CHANGE_PENDING flag since it can't get lock which was held by md_attr_store already. To solve the deadlock problem, we move "->resync_finish()" from md_do_sync to md_reap_sync_thread (after md_update_sb), also MD_HELD_RESYNC_LOCK is introduced since it is possible that node can't get resync lock in md_do_sync. Then we do not need to wait for MD_CHANGE_PENDING is cleared or not since metadata should be updated after md_update_sb, so just call resync_finish if MD_HELD_RESYNC_LOCK is set. We also unified the code after skip label, since set PENDING for non-clustered case should be harmless. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
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