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path: root/drivers/md/dm-mpath.c
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2020-08-07Merge tag 'for-5.9/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: - DM multipath locking fixes around m->flags tests and improvements to bio-based code so that it follows patterns established by request-based code. - Request-based DM core improvement to eliminate unnecessary call to blk_mq_queue_stopped(). - Add "panic_on_corruption" error handling mode to DM verity target. - DM bufio fix to to perform buffer cleanup from a workqueue rather than wait for IO in reclaim context from shrinker. - DM crypt improvement to optionally avoid async processing via workqueues for reads and/or writes -- via "no_read_workqueue" and "no_write_workqueue" features. This more direct IO processing improves latency and throughput with faster storage. Avoiding workqueue IO submission for writes (DM_CRYPT_NO_WRITE_WORKQUEUE) is a requirement for adding zoned block device support to DM crypt. - Add zoned block device support to DM crypt. Makes use of DM_CRYPT_NO_WRITE_WORKQUEUE and a new optional feature (DM_CRYPT_WRITE_INLINE) that allows write completion to wait for encryption to complete. This allows write ordering to be preserved, which is needed for zoned block devices. - Fix DM ebs target's check for REQ_OP_FLUSH. - Fix DM core's report zones support to not report more zones than were requested. - A few small compiler warning fixes. - DM dust improvements to return output directly to the user rather than require they scrape the system log for output. * tag 'for-5.9/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: dm: don't call report zones for more than the user requested dm ebs: Fix incorrect checking for REQ_OP_FLUSH dm init: Set file local variable static dm ioctl: Fix compilation warning dm raid: Remove empty if statement dm verity: Fix compilation warning dm crypt: Enable zoned block device support dm crypt: add flags to optionally bypass kcryptd workqueues dm bufio: do buffer cleanup from a workqueue dm rq: don't call blk_mq_queue_stopped() in dm_stop_queue() dm dust: add interface to list all badblocks dm dust: report some message results directly back to user dm verity: add "panic_on_corruption" error handling mode dm mpath: use double checked locking in fast path dm mpath: rename current_pgpath to pgpath in multipath_prepare_ioctl dm mpath: rework __map_bio() dm mpath: factor out multipath_queue_bio dm mpath: push locking down to must_push_back_rq() dm mpath: take m->lock spinlock when testing QUEUE_IF_NO_PATH dm mpath: changes from initial m->flags locking audit
2020-07-13dm mpath: use double checked locking in fast pathMike Snitzer
Fast-path code biased toward lazy acknowledgement of bit being set (primarily only for initialization). Multipath code is very retry oriented so even if state is missed it'll recover. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-13dm mpath: rename current_pgpath to pgpath in multipath_prepare_ioctlMike Snitzer
Makes consistent with __map_bio() and multipath_clone_and_map(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-13dm mpath: rework __map_bio()Mike Snitzer
so that it follows same pattern as request-based multipath_clone_and_map() Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-13dm mpath: factor out multipath_queue_bioMike Snitzer
Enables further cleanup. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-13dm mpath: push locking down to must_push_back_rq()Mike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-13dm mpath: take m->lock spinlock when testing QUEUE_IF_NO_PATHMike Snitzer
Fix multipath_end_io, multipath_end_io_bio and multipath_busy to take m->lock while testing if MPATHF_QUEUE_IF_NO_PATH bit is set. These are all slow-path cases when no paths are available so extra locking isn't a performance hit. Correctness matters most. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-07-13dm mpath: changes from initial m->flags locking auditMike Snitzer
Fix locking in slow-paths where m->lock should be taken. Signed-off-by: Mike Snitzer <snitzer@rredhat.com>
2020-07-01block: rename generic_make_request to submit_bio_noacctChristoph Hellwig
generic_make_request has always been very confusingly misnamed, so rename it to submit_bio_noacct to make it clear that it is submit_bio minus accounting and a few checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-05dm mpath: add DM device name to Failing/Reinstating path log messagesMike Snitzer
When there are many DM multipath devices it really helps to have additional context for which DM device a failed or reinstated path is part of. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-06-05dm mpath: enhance queue_if_no_path debuggingMike Snitzer
Add more DMDEBUG that shows arguments passed and caller, and another that shows state of related flags at end of queue_if_no_path(). Also add queue_if_no_path DMDEBUG to multipath_resume(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-06-05dm mpath: restrict queue_if_no_path state machineMike Snitzer
Do not allow saving disabled queue_if_no_path if already saved as enabled; implies multiple suspends (which shouldn't ever happen). Log if this unlikely scenario is ever triggered. Also, only write MPATHF_SAVED_QUEUE_IF_NO_PATH during presuspend or if "fail_if_no_path" message. MPATHF_SAVED_QUEUE_IF_NO_PATH is no longer always modified, e.g.: even if queue_if_no_path()'s save_old_value argument wasn't set. This just implies a bit tighter control over the management of MPATHF_SAVED_QUEUE_IF_NO_PATH. Side-effect is multipath_resume() doesn't reset MPATHF_QUEUE_IF_NO_PATH unless MPATHF_SAVED_QUEUE_IF_NO_PATH was set (during presuspend); and at that time the MPATHF_SAVED_QUEUE_IF_NO_PATH bit gets cleared. So MPATHF_SAVED_QUEUE_IF_NO_PATH's use is much more narrow in scope. Last, but not least, do _not_ disable queue_if_no_path during noflush suspend. There is no need/benefit to saving off queue_if_no_path via MPATHF_SAVED_QUEUE_IF_NO_PATH and clearing MPATHF_QUEUE_IF_NO_PATH for noflush suspend -- by avoiding this needless queue_if_no_path flag churn there is less potential for MPATHF_QUEUE_IF_NO_PATH to get lost. Which avoids potential for IOs to be errored back up to userspace during DM multipath's handling of path failures. That said, this last change papers over a reported issue concerning request-based dm-multipath's interaction with blk-mq, relative to suspend and resume: multipath_endio is being called _before_ multipath_resume. This should never happen if DM suspend's blk_mq_quiesce_queue() + dm_wait_for_completion() is genuinely waiting for all inflight blk-mq requests to complete. Similarly: drivers/md/dm.c:__dm_resume() clearly calls dm_table_resume_targets() _before_ dm_start_queue()'s blk_mq_unquiesce_queue() is called. If the queue isn't even restarted until after multipath_resume(); the BIG question that still needs answering is: how can multipath_end_io beat multipath_resume in a race!? Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-06-05dm mpath: simplify __must_push_backMike Snitzer
Remove micro-optimization that infers device is between presuspend and resume (was done purely to avoid call to dm_noflush_suspending, which isn't expensive anyway). Remove flags argument since they are no longer checked. And remove must_push_back_bio() since it was simply a call to __must_push_back(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-05-20dm: use DMDEBUG macros now that they use pr_debug variantsMike Snitzer
Now that DMDEBUG uses pr_debug and DMDEBUG_LIMIT uses pr_debug_ratelimited cleanup DM's 2 direct pr_debug callers to use them to get the benefit of consistent DM_FMT formatting of debugging messages. While doing so, dm-mpath.c:dm_report_EIO() was switched over to using DMDEBUG_LIMIT due to the potential for error handling floods in the IO completion path. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-05-15dm mpath: pass IO start time to path selectorGabriel Krisman Bertazi
The HST path selector needs this information to perform path prediction. For request-based mpath, struct request's io_start_time_ns is used, while for bio-based, use the start_time stored in dm_io. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-05-15dm mpath: switch paths in dm_blk_ioctl() code pathMartin Wilck
SCSI LUN passthrough code such as qemu's "scsi-block" device model pass every IO to the host via SG_IO ioctls. Currently, dm-multipath calls choose_pgpath() only in the block IO code path, not in the ioctl code path (unless current_pgpath is NULL). This has the effect that no path switching and thus no load balancing is done for SCSI-passthrough IO, unless the active path fails. Fix this by using the same logic in multipath_prepare_ioctl() as in multipath_clone_and_map(). Note: The allegedly best path selection algorithm, service-time, still wouldn't work perfectly, because the io size of the current request is always set to 0. Changing that for the IO passthrough case would require the ioctl cmd and arg to be passed to dm's prepare_ioctl() method. Signed-off-by: Martin Wilck <mwilck@suse.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-04-28dm multipath: use updated MPATHF_QUEUE_IO on mapping for bio-based mpathGabriel Krisman Bertazi
When adding devices that don't have a scsi_dh on a BIO based multipath, I was able to consistently hit the warning below and lock-up the system. The problem is that __map_bio reads the flag before it potentially being modified by choose_pgpath, and ends up using the older value. The WARN_ON below is not trivially linked to the issue. It goes like this: The activate_path delayed_work is not initialized for non-scsi_dh devices, but we always set MPATHF_QUEUE_IO, asking for initialization. That is fine, since MPATHF_QUEUE_IO would be cleared in choose_pgpath. Nevertheless, only for BIO-based mpath, we cache the flag before calling choose_pgpath, and use the older version when deciding if we should initialize the path. Therefore, we end up trying to initialize the paths, and calling the non-initialized activate_path work. [ 82.437100] ------------[ cut here ]------------ [ 82.437659] WARNING: CPU: 3 PID: 602 at kernel/workqueue.c:1624 __queue_delayed_work+0x71/0x90 [ 82.438436] Modules linked in: [ 82.438911] CPU: 3 PID: 602 Comm: systemd-udevd Not tainted 5.6.0-rc6+ #339 [ 82.439680] RIP: 0010:__queue_delayed_work+0x71/0x90 [ 82.440287] Code: c1 48 89 4a 50 81 ff 00 02 00 00 75 2a 4c 89 cf e9 94 d6 07 00 e9 7f e9 ff ff 0f 0b eb c7 0f 0b 48 81 7a 58 40 74 a8 94 74 a7 <0f> 0b 48 83 7a 48 00 74 a5 0f 0b eb a1 89 fe 4c 89 cf e9 c8 c4 07 [ 82.441719] RSP: 0018:ffffb738803977c0 EFLAGS: 00010007 [ 82.442121] RAX: ffffa086389f9740 RBX: 0000000000000002 RCX: 0000000000000000 [ 82.442718] RDX: ffffa086350dd930 RSI: ffffa0863d76f600 RDI: 0000000000000200 [ 82.443484] RBP: 0000000000000200 R08: 0000000000000000 R09: ffffa086350dd970 [ 82.444128] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa086350dd930 [ 82.444773] R13: ffffa0863d76f600 R14: 0000000000000000 R15: ffffa08636738008 [ 82.445427] FS: 00007f6abfe9dd40(0000) GS:ffffa0863dd80000(0000) knlGS:00000 [ 82.446040] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 82.446478] CR2: 0000557d288db4e8 CR3: 0000000078b36000 CR4: 00000000000006e0 [ 82.447104] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 82.447561] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 82.448012] Call Trace: [ 82.448164] queue_delayed_work_on+0x6d/0x80 [ 82.448472] __pg_init_all_paths+0x7b/0xf0 [ 82.448714] pg_init_all_paths+0x26/0x40 [ 82.448980] __multipath_map_bio.isra.0+0x84/0x210 [ 82.449267] __map_bio+0x3c/0x1f0 [ 82.449468] __split_and_process_non_flush+0x14a/0x1b0 [ 82.449775] __split_and_process_bio+0xde/0x340 [ 82.450045] ? dm_get_live_table+0x5/0xb0 [ 82.450278] dm_process_bio+0x98/0x290 [ 82.450518] dm_make_request+0x54/0x120 [ 82.450778] generic_make_request+0xd2/0x3e0 [ 82.451038] ? submit_bio+0x3c/0x150 [ 82.451278] submit_bio+0x3c/0x150 [ 82.451492] mpage_readpages+0x129/0x160 [ 82.451756] ? bdev_evict_inode+0x1d0/0x1d0 [ 82.452033] read_pages+0x72/0x170 [ 82.452260] __do_page_cache_readahead+0x1ba/0x1d0 [ 82.452624] force_page_cache_readahead+0x96/0x110 [ 82.452903] generic_file_read_iter+0x84f/0xae0 [ 82.453192] ? __seccomp_filter+0x7c/0x670 [ 82.453547] new_sync_read+0x10e/0x190 [ 82.453883] vfs_read+0x9d/0x150 [ 82.454172] ksys_read+0x65/0xe0 [ 82.454466] do_syscall_64+0x4e/0x210 [ 82.454828] entry_SYSCALL_64_after_hwframe+0x49/0xbe [...] [ 82.462501] ---[ end trace bb39975e9cf45daa ]--- Cc: stable@vger.kernel.org Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-03-03dm: bump version of core and various targetsMike Snitzer
Changes made during the 5.6 cycle warrant bumping the version number for DM core and the targets modified by this commit. It should be noted that dm-thin, dm-crypt and dm-raid already had their target version bumped during the 5.6 merge window. Signed-off-by; Mike Snitzer <snitzer@redhat.com>
2020-01-14dm mpath: Add timeout mechanism for queue_if_no_pathAnatol Pomazau
Add a configurable timeout mechanism to disable queue_if_no_path without assistance from userspace multipathd. This reimplements multipathd's no_path_retry mechanism in kernel space. This is motivated by the desire to prevent processes from hanging indefinitely waiting for IO in cases where multipathd might be unable to respond (after a failure or for whatever reason). Despite replicating userspace multipathd's policy configuration in kernel space, it is important to prevent IOs from hanging forever, waiting for userspace that may be incapable of behaving correctly. Use of the provided "queue_if_no_path_timeout_secs" dm-multipath module parameter is optional. This timeout mechanism is disabled by default (by being set to 0). Signed-off-by: Anatol Pomazau <anatol@google.com> Co-developed-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-01-07dm mpath: use true/false for bool variablezhengbin
Fixes coccicheck warning: drivers/md/dm-mpath.c:1447:2-13: WARNING: Assignment of 0/1 to bool variable Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: zhengbin <zhengbin13@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-11-26dm mpath: remove harmful bio-based optimizationMike Snitzer
Removes the branching for edge-case where no SCSI device handler exists. The __map_bio_fast() method was far too limited, by only selecting a new pathgroup or path IFF there was a path failure, fix this be eliminating it in favor of __map_bio(). __map_bio()'s extra SCSI device handler specific MPATHF_PG_INIT_REQUIRED test is not in the fast path anyway. This change restores full path selector functionality for bio-based configurations that don't haave a SCSI device handler. But it should be noted that the path selectors do have an impact on performance for certain networks that are extremely fast (and don't require frequent switching). Fixes: 8d47e65948dd ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks") Cc: stable@vger.kernel.org Reported-by: Drew Hastings <dhastings@crucialwebhost.com> Suggested-by: Martin Wilck <mwilck@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-04-30dm mpath: always free attached_handler_name in parse_path()Martin Wilck
Commit b592211c33f7 ("dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer") fixed a memory leak for the case where setup_scsi_dh() returns failure. But setup_scsi_dh may return success and not "use" attached_handler_name if the retain_attached_hwhandler flag is not set on the map. As setup_scsi_sh properly "steals" the pointer by nullifying it, freeing it unconditionally in parse_path() is safe. Fixes: b592211c33f7 ("dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointer") Cc: stable@vger.kernel.org Reported-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Martin Wilck <mwilck@suse.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-04-25dm mpath: fix missing call of path selector type->end_ioYufen Yu
After commit 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback"), map_request() will requeue the tio when issued clone request return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE. Thus, if device driver status is error, a tio may be requeued multiple times until the return value is not DM_MAPIO_REQUEUE. That means type->start_io may be called multiple times, while type->end_io is only called when IO complete. In fact, even without commit 396eaf21ee17, setup_clone() failure can also cause tio requeue and associated missed call to type->end_io. The service-time path selector selects path based on in_flight_size, which is increased by st_start_io() and decreased by st_end_io(). Missed calls to st_end_io() can lead to in_flight_size count error and will cause the selector to make the wrong choice. In addition, queue-length path selector will also be affected. To fix the problem, call type->end_io in ->release_clone_rq before tio requeue. map_info is passed to ->release_clone_rq() for map_request() error path that result in requeue. Fixes: 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback") Cc: stable@vger.kernl.org Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-12-18dm mpath: only flush workqueue when neededwuzhouhui
The workqueues are shared by many multipath devices, only flush whole workqueue when necessary. Otherwise, we just flush works as needed. Signed-off-by: wuzhouhui <wuzhouhui14@mails.ucas.ac.cn> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-11dm: rename DM_TYPE_MQ_REQUEST_BASED to DM_TYPE_REQUEST_BASEDMike Snitzer
Now that request-based DM is only using blk-mq, there is no need to differentiate between legacy "rq" and new "mq". We're back to a single request-based DM -- and there was much rejoicing! Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-10-11dm: remove legacy request-based IO pathJens Axboe
dm supports both, and since we're killing off the legacy path in general, get rid of it in dm. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-09-17dm mpath: fix attached_handler_name leak and dangling hw_handler_name pointerMike Snitzer
Commit e8f74a0f0011 ("dm mpath: eliminate need to use scsi_device_from_queue") introduced 2 regressions: 1) memory leak occurs if attached_handler_name is not assigned to m->hw_handler_name 2) m->hw_handler_name can become a dangling pointer if the RETAIN_ATTACHED_HW_HANDLER flag is set and scsi_dh_attach() returns -EBUSY. Fix both of these by clearing 'attached_handler_name' pointer passed to setup_scsi_dh() after it is assigned to m->hw_handler_name. And if setup_scsi_dh() doesn't consume 'attached_handler_name' parse_path() will kfree() it. Fixes: e8f74a0f0011 ("dm mpath: eliminate need to use scsi_device_from_queue") Cc: stable@vger.kernel.org # 4.16+ Reported-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-05-14block: sanitize blk_get_request calling conventionsChristoph Hellwig
Switch everyone to blk_get_request_flags, and then rename blk_get_request_flags to blk_get_request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-04dm: remove fmode_t argument from .prepare_ioctl hookMike Snitzer
Use the fmode_t that is passed to dm_blk_ioctl() rather than inconsistently (varies across targets) drop it on the floor by overriding it with the fmode_t stored in 'struct dm_dev'. All the persistent reservation functions weren't using the fmode_t they got back from .prepare_ioctl so remove them. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-04-03dm mpath: use DM_MAPIO_SUBMITTED instead of magic number 0 in ↵Wang Sheng-Hui
process_queued_bios() Signed-off-by: Wang Sheng-Hui <shhuiw@foxmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-04-03dm: allow targets to return output from messages they are sentMike Snitzer
Could be useful for a target to return stats or other information. If a target does DMEMIT() anything to @result from its .message method then it must return 1 to the caller. Signed-off-By: Mike Snitzer <snitzer@redhat.com>
2018-03-29dm mpath: fix support for loading scsi_dh modules during table loadMike Snitzer
The ability to have multipath dynamically attach a scsi_dh, that the user specified in the multipath table, was broken by commit e8f74a0f00 ("dm mpath: eliminate need to use scsi_device_from_queue"). Restore the ability to load, and attach, a particular scsi_dh module if one is specified (as noticed by checking m->hw_handler_name). Fixes: e8f74a0f00 ("dm mpath: eliminate need to use scsi_device_from_queue") Reported-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-03-14dm mpath: fix passing integrity dataSteffen Maier
After v4.12 commit e2460f2a4bc7 ("dm: mark targets that pass integrity data"), dm-multipath, e.g. on DIF+DIX SCSI disk paths, does not support block integrity any more. So add it to the whitelist. This is also a pre-requisite to use block integrity with other dm layer(s) on top of multipath, such as kpartx partitions (dm-linear) or LVM. Also, bump target version to reflect this fix. Fixes: e2460f2a4bc7 ("dm: mark targets that pass integrity data") Cc: <stable@vger.kernel.org> #4.12+ Bisected-by: Fedor Loshakov <loshakov@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-03-13dm mpath: eliminate need to use scsi_device_from_queueMike Snitzer
Instead of scsi_device_from_queue(), use scsi_dh_attached_handler_name() -- whose implementation uses scsi_device_from_queue() to avoid trying to access SCSI-specific resources from non-SCSI devices. Fixes buildbot reported issue when CONFIG_SCSI isn't set: ERROR: "scsi_device_from_queue" [drivers/md/dm-multipath.ko] undefined! Fixes: 8d47e65948dd ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks") Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-03-13dm mpath: fix uninitialized 'pg_init_wait' waitqueue_head NULL pointerMike Snitzer
Initialize all the scsi_dh related 'struct multipath' members regardless of whether a scsi_dh is in use or not. The subtle (and fragile) SCSI-assuming legacy code clearly needs further decoupling from non-SCSI (and/or developer understanding). Fixes: 8d47e65948dd ("dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checks") Reported-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-03-06dm mpath: remove unnecessary NVMe branching in favor of scsi_dh checksMike Snitzer
This eliminates the "queue_mode" configuration's "nvme" mode. There wasn't anything NVMe-specific about that mode. It was named "nvme" because it was a short name for the mode. But the entire point of the mode was to optimize the multipath target for underlying devices that are _not_ SCSI-based. Devices that aren't SCSI have no need for the various SCSI device handler (scsi_dh) specific code in DM multipath. But rather than narrowly define this scsi_dh vs not branching in terms of "nvme": invert the logic so that we're just checking whether a multipath device is layered on SCSI devices with scsi_dh attached. This allows any future storage technology to avoid scsi_dh specific code in the multipath target too. Fixes: 848b8aefd4 ("dm mpath: optimize NVMe bio-based support") Suggested-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-31Merge tag 'for-4.16/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: - DM core fixes to ensure that bio submission follows a depth-first tree walk; this is critical to allow forward progress without the need to use the bioset's BIOSET_NEED_RESCUER. - Remove DM core's BIOSET_NEED_RESCUER based dm_offload infrastructure. - DM core cleanups and improvements to make bio-based DM more efficient (e.g. reduced memory footprint as well leveraging per-bio-data more). - Introduce new bio-based mode (DM_TYPE_NVME_BIO_BASED) that leverages the more direct IO submission path in the block layer; this mode is used by DM multipath and also optimizes targets like DM thin-pool that stack directly on NVMe data device. - DM multipath improvements to factor out legacy SCSI-only (e.g. scsi_dh) code paths to allow for more optimized support for NVMe multipath. - A fix for DM multipath path selectors (service-time and queue-length) to select paths in a more balanced way; largely academic but doesn't hurt. - Numerous DM raid target fixes and improvements. - Add a new DM "unstriped" target that enables Intel to workaround firmware limitations in some NVMe drives that are striped internally (this target also works when stacked above the DM "striped" target). - Various Documentation fixes and improvements. - Misc cleanups and fixes across various DM infrastructure and targets (e.g. bufio, flakey, log-writes, snapshot). * tag 'for-4.16/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (69 commits) dm cache: Documentation: update default migration_throttling value dm mpath selector: more evenly distribute ties dm unstripe: fix target length versus number of stripes size check dm thin: fix trailing semicolon in __remap_and_issue_shared_cell dm table: fix NVMe bio-based dm_table_determine_type() validation dm: various cleanups to md->queue initialization code dm mpath: delay the retry of a request if the target responded as busy dm mpath: return DM_MAPIO_DELAY_REQUEUE if QUEUE_IO or PG_INIT_REQUIRED dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failure dm log writes: fix max length used for kstrndup dm: backfill missing calls to mutex_destroy() dm snapshot: use mutex instead of rw_semaphore dm flakey: check for null arg_name in parse_features() dm thin: extend thinpool status format string with omitted fields dm thin: fixes in thin-provisioning.txt dm thin: document representation of <highest mapped sector> when there is none dm thin: fix documentation relative to low water mark threshold dm cache: be consistent in specifying sectors and SI units in cache.txt dm cache: delete obsoleted paragraph in cache.txt dm cache: fix grammar in cache-policies.txt ...
2018-01-29dm mpath: delay the retry of a request if the target responded as busyMike Snitzer
Add DM_ENDIO_DELAY_REQUEUE to allow request-based multipath's multipath_end_io() to instruct dm-rq.c:dm_done() to delay a requeue. This is beneficial to do if BLK_STS_RESOURCE is returned from the target (because target is busy). Relative to blk-mq: kick the hw queues via blk_mq_requeue_work(), indirectly from dm-rq.c:__dm_mq_kick_requeue_list(), after a delay. For old .request_fn: use blk_delay_queue(). bio-based multipath doesn't have feature parity with request-based for retryable error requeues; that is something that'll need fixing in the future. Suggested-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Bart Van Assche <bart.vanassche@wdc.com> [as interpreted from Bart's "... patch looks fine to me."]
2018-01-17dm mpath: return DM_MAPIO_DELAY_REQUEUE if QUEUE_IO or PG_INIT_REQUIREDMing Lei
Avoid using DM_MAPIO_REQUEUE unless absolutely necessary because it results in dm-rq.c:dm_mq_queue_rq() returning BLK_STS_RESOURCE to blk-mq -- doing so should only ever be done if the underlying queue is out of resources. So switch to returning DM_MAPIO_DELAY_REQUEUE from multipath_clone_and_map() if either MPATHF_QUEUE_IO or MPATHF_PG_INIT_REQUIRED are set. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-17dm mpath: return DM_MAPIO_REQUEUE on blk-mq rq allocation failureMing Lei
blk-mq will rerun queue via RESTART or dispatch wake after one request is completed, so not necessary to wait random time for requeuing, we should trust blk-mq to do it. More importantly, we need to return BLK_STS_RESOURCE to blk-mq so that dequeuing from the I/O scheduler can be stopped, this results in improved I/O merging. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-17dm: backfill missing calls to mutex_destroy()Mike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-10dm mpath: Use blk_path_errorKeith Busch
Uses common code for determining if an error should be retried on alternate path. Acked-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-06dm mpath: factor out SCSI vs NVMe path selectionMike Snitzer
Trying to do both SCSI and NVMe bio-based handling with branching in the same common code has proven too tedious on a code maintenance level. In addition it slightly hurts IO performance. Fix this by factoring out __map_bio() and __map_bio_nvme(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-06dm mpath: optimize NVMe bio-based supportMike Snitzer
All code that deals with pg_init is not used with bio-based NVMe mode. This includes skipping initialization of pg_init related variables. Also, pg_init related members on 'struct multipath' have been grouped together. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-04dm mpath: implement NVMe bio-based supportMike Snitzer
This DM multipath NVMe bio-based support requires CONFIG_NVME_MULTIPATH to not be set. In the future hopefully NVMe multipath and DM multipath can co-exist more seemlessly. But as is, if CONFIG_NVME_MULTIPATH=Y then all the individal NVMe paths will remain hidden to upper layers and as such DM multipath will not be able to manage them. Though NVMe's native multipathing doesn't multipath namespaces across subsystems; so technically a user _could_ use CONFIG_NVME_MULTIPATH=Y and also use DM multipath to multipath across subsystems. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-01-03dm mpath: move dm_bio_restore out of endio methodMike Snitzer
Moving the dm_bio_restore() to process_queued_bios() avoids doing that work in multipath_end_io_bio(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-20dm mpath: optimize retrieval of bio_details from per-bio-dataMike Snitzer
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-20dm mpath: remove unnecessary memset() calls for per-io-dataMike Snitzer
All underlying members are initialized directly so the memset() calls are not needed. Also, initialize mpio->nr_bytes from the start since it never changes. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-20dm mpath: remove unused param from multipath_init_per_bio_data()Mike Snitzer
'struct dm_bio_details *' isn't ever needed. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-12-08dm mpath: fix bio-based multipath queue_if_no_path handlingMike Snitzer
Commit ca5beb76 ("dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH") caused bio-based DM-multipath to fail mptest's "test_02_sdev_delete". Restoring the logic that existed prior to commit ca5beb76 fixes this bio-based DM-multipath regression. Also verified all mptest tests pass with request-based DM-multipath. This commit effectively reverts commit ca5beb76 -- but it does so without reintroducing the need to take the m->lock spinlock in must_push_back_{rq,bio}. Fixes: ca5beb76 ("dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH") Cc: stable@vger.kernel.org # 4.12+ Signed-off-by: Mike Snitzer <snitzer@redhat.com>