talos-obmc-linux/block, branch dev-5.0

block, bfq: fix queue removal from weights tree

2019-04-05T20:34:45+00:00

[ Upstream commit 9dee8b3b057e1da26f85f1842f2aaf3bb200fb94 ] bfq maintains an ordered list, through a red-black tree, of unique weights of active bfq_queues. This list is used to detect whether there are active queues with differentiated weights. The weight of a queue is removed from the list when both the following two conditions become true: (1) the bfq_queue is flagged as inactive (2) the has no in-flight request any longer; Unfortunately, in the rare cases where condition (2) becomes true before condition (1), the removal fails, because the function to remove the weight of the queue (bfq_weights_tree_remove) is rightly invoked in the path that deactivates the bfq_queue, but mistakenly invoked *before* the function that actually performs the deactivation (bfq_deactivate_bfqq). This commits moves the invocation of bfq_weights_tree_remove for condition (1) to after bfq_deactivate_bfqq. As a consequence of this move, it is necessary to add a further reference to the queue when the weight of a queue is added, because the queue might otherwise be freed before bfq_weights_tree_remove is invoked. This commit adds this reference and makes all related modifications. Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block, bfq: fix in-service-queue check for queue merging

2019-04-05T20:34:45+00:00

[ Upstream commit 058fdecc6de7cdecbf4c59b851e80eb2d6c5295f ] When a new I/O request arrives for a bfq_queue, say Q, bfq checks whether that request is close to (a) the head request of some other queue waiting to be served, or (b) the last request dispatched for the in-service queue (in case Q itself is not the in-service queue) If a queue, say Q2, is found for which the above condition holds, then bfq merges Q and Q2, to hopefully get a more sequential I/O in the resulting merged queue, and thus a possibly higher throughput. Case (b) is checked by comparing the new request for Q with the last request dispatched, assuming that the latter necessarily belonged to the in-service queue. Unfortunately, this assumption is no longer always correct, since commit d0edc2473be9 ("block, bfq: inject other-queue I/O into seeky idle queues on NCQ flash"). When the assumption does not hold, queues that must not be merged may be merged, causing unexpected loss of control on per-queue service guarantees. This commit solves this problem by adding an extra field, which stores the actual last request dispatched for the in-service queue, and by using this new field to correctly check case (b). Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

blk-mq: fix sbitmap ws_active for shared tags

2019-04-03T04:27:34+00:00

commit e861857545567adec8da3bdff728efdf7db12285 upstream. We now wrap sbitmap waitqueues in an active counter, so we can avoid iterating wakeups unless we have waiters there. This works as long as everyone that's manipulating the waitqueues use the proper helpers. For the tag wait case for shared tags, however, we add ourselves to the waitqueue without incrementing/decrementing the ->ws_active count. This means that wakeups can take a long time to happen. Fix this by manually doing the inc/dec as needed for the wait queue handling. Reported-by: Michael Leun Tested-by: Michael Leun Cc: stable@vger.kernel.org Reviewed-by: Omar Sandoval Fixes: 5d2ee7122c73 ("sbitmap: optimize wakeup check") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

Merge tag 'for-linus-20190215' of git://git.kernel.dk/linux-block

2019-02-15T17:12:28+00:00

Pull block fixes from Jens Axboe: - Ensure we insert into the hctx dispatch list, if a request is marked as DONTPREP (Jianchao) - NVMe pull request, single missing unlock on error fix (Keith) - MD pull request, single fix for a potentially data corrupting issue (Nate) - Floppy check_events regression fix (Yufen) * tag 'for-linus-20190215' of git://git.kernel.dk/linux-block: md/raid1: don't clear bitmap bits on interrupted recovery. floppy: check_events callback should not return a negative number nvme-pci: add missing unlock for reset error blk-mq: insert rq with DONTPREP to hctx dispatch list when requeue

blk-mq: insert rq with DONTPREP to hctx dispatch list when requeue

2019-02-12T02:51:52+00:00

When requeue, if RQF_DONTPREP, rq has contained some driver specific data, so insert it to hctx dispatch list to avoid any merge. Take scsi as example, here is the trace event log (no io scheduler, because RQF_STARTED would prevent merging), kworker/0:1H-339 [000] ...1 2037.209289: block_rq_insert: 8,0 R 4096 () 32768 + 8 [kworker/0:1H] scsi_inert_test-1987 [000] .... 2037.220465: block_bio_queue: 8,0 R 32776 + 8 [scsi_inert_test] scsi_inert_test-1987 [000] ...2 2037.220466: block_bio_backmerge: 8,0 R 32776 + 8 [scsi_inert_test] kworker/0:1H-339 [000] .... 2047.220913: block_rq_issue: 8,0 R 8192 () 32768 + 16 [kworker/0:1H] scsi_inert_test-1996 [000] ..s1 2047.221007: block_rq_complete: 8,0 R () 32768 + 8 [0] scsi_inert_test-1996 [000] .Ns1 2047.221045: block_rq_requeue: 8,0 R () 32776 + 8 [0] kworker/0:1H-339 [000] ...1 2047.221054: block_rq_insert: 8,0 R 4096 () 32776 + 8 [kworker/0:1H] kworker/0:1H-339 [000] ...1 2047.221056: block_rq_issue: 8,0 R 4096 () 32776 + 8 [kworker/0:1H] scsi_inert_test-1986 [000] ..s1 2047.221119: block_rq_complete: 8,0 R () 32776 + 8 [0] (32768 + 8) was requeued by scsi_queue_insert and had RQF_DONTPREP. Then it was merged with (32776 + 8) and issued. Due to RQF_DONTPREP, the sdb only contained the part of (32768 + 8), then only that part was completed. The lucky thing was that scsi_io_completion detected it and requeued the remaining part. So we didn't get corrupted data. However, the requeue of (32776 + 8) is not expected. Suggested-by: Jens Axboe Signed-off-by: Jianchao Wang Signed-off-by: Jens Axboe

Merge tag 'for-linus-20190209' of git://git.kernel.dk/linux-block

2019-02-09T18:26:09+00:00

Pull block fixes from Jens Axboe: - NVMe pull request from Christoph, fixing namespace locking when dealing with the effects log, and a rapid add/remove issue (Keith) - blktrace tweak, ensuring requests with -1 sectors are shown (Jan) - link power management quirk for a Smasung SSD (Hans) - m68k nfblock dynamic major number fix (Chengguang) - series fixing blk-iolatency inflight counter issue (Liu) - ensure that we clear ->private when setting up the aio kiocb (Mike) - __find_get_block_slow() rate limit print (Tetsuo) * tag 'for-linus-20190209' of git://git.kernel.dk/linux-block: blk-mq: remove duplicated definition of blk_mq_freeze_queue Blk-iolatency: warn on negative inflight IO counter blk-iolatency: fix IO hang due to negative inflight counter blktrace: Show requests without sector fs: ratelimit __find_get_block_slow() failure message. m68k: set proper major_num when specifying module param major_num libata: Add NOLPM quirk for SAMSUNG MZ7TE512HMHP-000L1 SSD nvme-pci: fix rapid add remove sequence nvme: lock NS list changes while handling command effects aio: initialize kiocb private in case any filesystems expect it.

blk-mq: remove duplicated definition of blk_mq_freeze_queue

2019-02-08T19:42:29+00:00

As the prototype has been defined in "include/linux/blk-mq.h", the one in "block/blk-mq.h" can be removed then. Signed-off-by: Liu Bo Signed-off-by: Jens Axboe

Blk-iolatency: warn on negative inflight IO counter

2019-02-08T19:42:27+00:00

This is to catch any unexpected negative value of inflight IO counter. Signed-off-by: Liu Bo Signed-off-by: Jens Axboe

blk-iolatency: fix IO hang due to negative inflight counter

2019-02-08T19:42:26+00:00

Our test reported the following stack, and vmcore showed that ->inflight counter is -1. [ffffc9003fcc38d0] __schedule at ffffffff8173d95d [ffffc9003fcc3958] schedule at ffffffff8173de26 [ffffc9003fcc3970] io_schedule at ffffffff810bb6b6 [ffffc9003fcc3988] blkcg_iolatency_throttle at ffffffff813911cb [ffffc9003fcc3a20] rq_qos_throttle at ffffffff813847f3 [ffffc9003fcc3a48] blk_mq_make_request at ffffffff8137468a [ffffc9003fcc3b08] generic_make_request at ffffffff81368b49 [ffffc9003fcc3b68] submit_bio at ffffffff81368d7d [ffffc9003fcc3bb8] ext4_io_submit at ffffffffa031be00 [ext4] [ffffc9003fcc3c00] ext4_writepages at ffffffffa03163de [ext4] [ffffc9003fcc3d68] do_writepages at ffffffff811c49ae [ffffc9003fcc3d78] __filemap_fdatawrite_range at ffffffff811b6188 [ffffc9003fcc3e30] filemap_write_and_wait_range at ffffffff811b6301 [ffffc9003fcc3e60] ext4_sync_file at ffffffffa030cee8 [ext4] [ffffc9003fcc3ea8] vfs_fsync_range at ffffffff8128594b [ffffc9003fcc3ee8] do_fsync at ffffffff81285abd [ffffc9003fcc3f18] sys_fsync at ffffffff81285d50 [ffffc9003fcc3f28] do_syscall_64 at ffffffff81003c04 [ffffc9003fcc3f50] entry_SYSCALL_64_after_swapgs at ffffffff81742b8e The ->inflight counter may be negative (-1) if 1) blk-iolatency was disabled when the IO was issued, 2) blk-iolatency was enabled before this IO reached its endio, 3) the ->inflight counter is decreased from 0 to -1 in endio() In fact the hang can be easily reproduced by the below script, H=/sys/fs/cgroup/unified/ P=/sys/fs/cgroup/unified/test echo "+io" > $H/cgroup.subtree_control mkdir -p $P echo $$ > $P/cgroup.procs xfs_io -f -d -c "pwrite 0 4k" /dev/sdg echo "`cat /sys/block/sdg/dev` target=1000000" > $P/io.latency xfs_io -f -d -c "pwrite 0 4k" /dev/sdg This fixes the problem by freezing the queue so that while enabling/disabling iolatency, there is no inflight rq running. Note that quiesce_queue is not needed as this only updating iolatency configuration about which dispatching request_queue doesn't care. Signed-off-by: Liu Bo Signed-off-by: Jens Axboe

Merge tag 'driver-core-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2019-02-08T18:53:44+00:00

Pull driver core fixes from Greg KH: "Here are some driver core fixes for 5.0-rc6. Well, not so much "driver core" as "debugfs". There's a lot of outstanding debugfs cleanup patches coming in through different subsystem trees, and in that process the debugfs core was found that it really should return errors when something bad happens, to prevent random files from showing up in the root of debugfs afterward. So debugfs was fixed up to handle this properly, and then two fixes for the relay and blk-mq code was needed as it was making invalid assumptions about debugfs return values. There's also a cacheinfo fix in here that resolves a tiny issue. All of these have been in linux-next for over a week with no reported problems" * tag 'driver-core-5.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: blk-mq: protect debugfs_create_files() from failures relay: check return of create_buf_file() properly debugfs: debugfs_lookup() should return NULL if not found debugfs: return error values, not NULL debugfs: fix debugfs_rename parameter checking cacheinfo: Keep the old value if of_property_read_u32 fails