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path: root/drivers/nvme/host/multipath.c
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2019-05-13nvme-multipath: avoid crash on invalid subsystem cntlid enumerationHannes Reinecke1-1/+1
A process holding an open reference to a removed disk prevents it from completing deletion, so its name continues to exist. A subsequent gendisk creation may have the same cntlid which risks collision when using that for the name. Use the unique ctrl->instance instead. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-05-01nvme-multipath: don't print ANA group state by defaultHannes Reinecke1-1/+1
Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-05-01nvme-multipath: split bios with the ns_head bio_set before submittingHannes Reinecke1-0/+8
If the bio is moved to a different queue via blk_steal_bios() and the original queue is destroyed in nvme_remove_ns() we'll be ending with a crash in bio_endio() as the mempool for the split bio bvecs had already been destroyed. So split the bio using the original queue (which will remain during the lifetime of the bio) before sending it down to the underlying device. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-03-28nvme-multipath: relax ANA state checkMartin George1-4/+1
When undergoing state transitions I/O might be requeued, hence we should always call nvme_mpath_set_live() to schedule requeue_work whenever the nvme device is live, independent on whether the old state was live or not. Signed-off-by: Martin George <marting@netapp.com> Signed-off-by: Gargi Srinivas <sring@netapp.com> Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-02-20nvme: convert to SPDX identifiersChristoph Hellwig1-9/+1
Update license to use SPDX-License-Identifier instead of verbose license text. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
2019-02-20nvme-multipath: round-robin I/O policyHannes Reinecke1-1/+85
Implement a simple round-robin I/O policy for multipathing. Path selection is done in two rounds, first iterating across all optimized paths, and if that doesn't return any valid paths, iterate over all optimized and non-optimized paths. If no paths are found, use the existing algorithm. Also add a sysfs attribute 'iopolicy' to switch between the current NUMA-aware I/O policy and the 'round-robin' I/O policy. Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-01-24nvme-multipath: drop optimization for static ANA group IDsHannes Reinecke1-2/+1
Bit 6 in the ANACAP field is used to indicate that the ANA group ID doesn't change while the namespace is attached to the controller. There is an optimisation in the code to only allocate space for the ANA group header, as the namespace list won't change and hence would not need to be refreshed. However, this optimisation was never carried over to the actual workflow, which always assumes that the buffer is large enough to hold the ANA header _and_ the namespace list. So drop this optimisation and always allocate enough space. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-01-09nvme-multipath: zero out ANA log bufferHannes Reinecke1-0/+2
When nvme_init_identify() fails the ANA log buffer is deallocated but _not_ set to NULL. This can cause double free oops when this controller is deleted without ever being reconnected. Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-12-08nvme: add a numa_node field to struct nvme_ctrlHannes Reinecke1-2/+2
Instead of directly poking into the struct device add a new numa_node field to struct nvme_ctrl. This allows fabrics drivers where ctrl->dev is a virtual device to support NUMA affinity as well. Also expose the field as a sysfs attribute, and populate it for the RDMA and FC transports. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-04nvme-mpath: remove I/O polling supportChristoph Hellwig1-16/+0
The ->poll_fn has been stale for a while, as a lot of places check for mq ops. But there is no real point in it anyway, as we don't even use the multipath code for subsystems without multiple ports, which is usually what we do high performance I/O to. If it really becomes an issue we should rework the nvme code to also skip the multipath code for any private namespace, even if that could mean some trouble when rescanning. Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-26block: make blk_poll() take a parameter on whether to spin or notJens Axboe1-2/+2
blk_poll() has always kept spinning until it found an IO. This is fine for SYNC polling, since we need to find one request we have pending, but in preparation for ASYNC polling it can be beneficial to just check if we have any entries available or not. Existing callers are converted to pass in 'spin == true', to retain the old behavior. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-19block: have ->poll_fn() return number of entries polledJens Axboe1-2/+2
We currently only really support sync poll, ie poll with 1 IO in flight. This prepares us for supporting async poll. Note that the returned value isn't necessarily 100% accurate. If poll races with IRQ completion, we assume that the fact that the task is now runnable means we found at least one entry. In reality it could be more than 1, or not even 1. This is fine, the caller will just need to take this into account. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-19Merge tag 'v4.20-rc3' into for-4.21/blockJens Axboe1-0/+1
Merge in -rc3 to resolve a few conflicts, but also to get a few important fixes that have gone into mainline since the block 4.21 branch was forked off (most notably the SCSI queue issue, which is both a conflict AND needed fix). Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove the lock argument to blk_alloc_queue_nodeChristoph Hellwig1-1/+1
With the legacy request path gone there is no real need to override the queue_lock. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-09nvme: make sure ns head inherits underlying device limitsSagi Grimberg1-0/+1
Whenever we update ns_head info, we need to make sure it is still compatible with all underlying backing devices because although nvme multipath doesn't have any explicit use of these limits, other devices can still be stacked on top of it which may rely on the underlying limits. Start with unlimited stacking limits, and every info update iterate over siblings and adjust queue limits. Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-17nvme: update node paths after adding new pathKeith Busch1-0/+9
The nvme namespace paths were being updated only when the current path was not set or nonoptimized. If a new path comes online that is a better path for its NUMA node, the multipath selector may continue using the previously set path on a potentially further node. This patch re-runs the path assignment after successfully adding a new optimized path. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-02nvme: take node locality into account when selecting a pathChristoph Hellwig1-11/+39
Make current_path an array with an entry for every possible node, and cache the best path on a per-node basis. Take the node distance into account when selecting it. This is primarily useful for dual-ported PCIe devices which are connected to PCIe root ports on different sockets. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Hannes Reinecke <hare@suse.com>
2018-10-02nvme: call nvme_complete_rq when nvmf_check_ready fails for mpath I/OJames Smart1-0/+7
When an io is rejected by nvmf_check_ready() due to validation of the controller state, the nvmf_fail_nonready_command() will normally return BLK_STS_RESOURCE to requeue and retry. However, if the controller is dying or the I/O is marked for NVMe multipath, the I/O is failed so that the controller can terminate or so that the io can be issued on a different path. Unfortunately, as this reject point is before the transport has accepted the command, blk-mq ends up completing the I/O and never calls nvme_complete_rq(), which is where multipath may preserve or re-route the I/O. The end result is, the device user ends up seeing an EIO error. Example: single path connectivity, controller is under load, and a reset is induced. An I/O is received: a) while the reset state has been set but the queues have yet to be stopped; or b) after queues are started (at end of reset) but before the reconnect has completed. The I/O finishes with an EIO status. This patch makes the following changes: - Adds the HOST_PATH_ERROR pathing status from TP4028 - Modifies the reject point such that it appears to queue successfully, but actually completes the io with the new pathing status and calls nvme_complete_rq(). - nvme_complete_rq() recognizes the new status, avoids resetting the controller (likely was already done in order to get this new status), and calls the multipather to clear the current path that errored. This allows the next command (retry or new command) to select a new path if there is one. Signed-off-by: James Smart <jsmart2021@gmail.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-10-01Merge tag 'v4.19-rc6' into for-4.20/blockJens Axboe1-2/+4
Merge -rc6 in, for two reasons: 1) Resolve a trivial conflict in the blk-mq-tag.c documentation 2) A few important regression fixes went into upstream directly, so they aren't in the 4.20 branch. Signed-off-by: Jens Axboe <axboe@kernel.dk> * tag 'v4.19-rc6': (780 commits) Linux 4.19-rc6 MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c cpufreq: qcom-kryo: Fix section annotations perf/core: Add sanity check to deal with pinned event failure xen/blkfront: correct purging of persistent grants Revert "xen/blkfront: When purging persistent grants, keep them in the buffer" selftests/powerpc: Fix Makefiles for headers_install change blk-mq: I/O and timer unplugs are inverted in blktrace dax: Fix deadlock in dax_lock_mapping_entry() x86/boot: Fix kexec booting failure in the SEV bit detection code bcache: add separate workqueue for journal_write to avoid deadlock drm/amd/display: Fix Edid emulation for linux drm/amd/display: Fix Vega10 lightup on S3 resume drm/amdgpu: Fix vce work queue was not cancelled when suspend Revert "drm/panel: Add device_link from panel device to DRM device" xen/blkfront: When purging persistent grants, keep them in the buffer clocksource/drivers/timer-atmel-pit: Properly handle error cases block: fix deadline elevator drain for zoned block devices ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set ... Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-28nvme: register ns_id attributes as default sysfs groupsHannes Reinecke1-11/+4
We should be registering the ns_id attribute as default sysfs attribute groups, otherwise we have a race condition between the uevent and the attributes appearing in sysfs. Suggested-by: Bart van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-28block: genhd: add 'groups' argument to device_add_diskHannes Reinecke1-1/+1
Update device_add_disk() to take an 'groups' argument so that individual drivers can register a device with additional sysfs attributes. This avoids race condition the driver would otherwise have if these groups were to be created with sysfs_add_groups(). Signed-off-by: Martin Wilck <martin.wilck@suse.com> Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-26nvme: properly propagate errors in nvme_mpath_initSusobhan Dey1-2/+4
Signed-off-by: Susobhan Dey <susobhan.dey@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-08-07nvme: fixup crash on failed discoveryHannes Reinecke1-1/+1
When the initial discovery fails the subsystem hasn't been setup yet in nvme_mpath_stop, and we can't dereference ctrl->subsys. Fixes: 0d0b660f ("nvme: add ANA support") Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-07-27nvme: add ANA supportChristoph Hellwig1-15/+327
Add support for Asynchronous Namespace Access as specified in NVMe 1.3 TP 4004. With ANA each namespace attached to a controller belongs to an ANA group that describes the characteristics of accessing the namespaces through this controller. In the optimized and non-optimized states namespaces can be accessed regularly, although in a multi-pathing environment we should always prefer to access a namespace through a controller where an optimized relationship exists. Namespaces in Inaccessible, Permanent-Loss or Change state for a given controller should not be accessed. The states are updated through reading the ANA log page, which is read once during controller initialization, whenever the ANA change notice AEN is received, or when one of the ANA specific status codes that signal a state change is received on a command. The ANA state is kept in the nvme_ns structure, which makes the checks in the fast path very simple. Updating the ANA state when reading the log page is also very simple, the only downside is that finding the initial ANA state when scanning for namespaces is a bit cumbersome. The gendisk for a ns_head is only registered once a live path for it exists. Without that the kernel would hang during partition scanning. Includes fixes and improvements from Hannes Reinecke. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
2018-07-27nvme: remove nvme_req_needs_failoverChristoph Hellwig1-7/+0
Now that we just call out to blk_path_error there isn't really any good reason to not merge it into the only caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
2018-06-11nvme: add bio remapping tracepointHannes Reinecke1-0/+4
Adding a tracepoint to trace bio remapping for native nvme multipath. Signed-off-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-05-03nvme/multipath: Fix multipath disabled naming collisionsKeith Busch1-0/+22
When CONFIG_NVME_MULTIPATH is set, but we're not using nvme to multipath, namespaces with multiple paths were not creating unique names due to reusing the same instance number from the namespace's head. This patch fixes this by falling back to the non-multipath naming method when the parameter disabled using multipath. Reported-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-05-03nvme/multipath: Disable runtime writable enabling parameterKeith Busch1-1/+1
We can't allow the user to change multipath settings at runtime, as this will create naming conflicts due to the different naming schemes used for each mode. Signed-off-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-06Merge tag 'for-4.17/block-20180402' of git://git.kernel.dk/linux-blockLinus Torvalds1-4/+4
Pull block layer updates from Jens Axboe: "It's a pretty quiet round this time, which is nice. This contains: - series from Bart, cleaning up the way we set/test/clear atomic queue flags. - series from Bart, fixing races between gendisk and queue registration and removal. - set of bcache fixes and improvements from various folks, by way of Michael Lyle. - set of lightnvm updates from Matias, most of it being the 1.2 to 2.0 transition. - removal of unused DIO flags from Nikolay. - blk-mq/sbitmap memory ordering fixes from Omar. - divide-by-zero fix for BFQ from Paolo. - minor documentation patches from Randy. - timeout fix from Tejun. - Alpha "can't write a char atomically" fix from Mikulas. - set of NVMe fixes by way of Keith. - bsg and bsg-lib improvements from Christoph. - a few sed-opal fixes from Jonas. - cdrom check-disk-change deadlock fix from Maurizio. - various little fixes, comment fixes, etc from various folks" * tag 'for-4.17/block-20180402' of git://git.kernel.dk/linux-block: (139 commits) blk-mq: Directly schedule q->timeout_work when aborting a request blktrace: fix comment in blktrace_api.h lightnvm: remove function name in strings lightnvm: pblk: remove some unnecessary NULL checks lightnvm: pblk: don't recover unwritten lines lightnvm: pblk: implement 2.0 support lightnvm: pblk: implement get log report chunk lightnvm: pblk: rename ppaf* to addrf* lightnvm: pblk: check for supported version lightnvm: implement get log report chunk helpers lightnvm: make address conversions depend on generic device lightnvm: add support for 2.0 address format lightnvm: normalize geometry nomenclature lightnvm: complete geo structure with maxoc* lightnvm: add shorten OCSSD version in geo lightnvm: add minor version to generic geometry lightnvm: simplify geometry structure lightnvm: pblk: refactor init/exit sequences lightnvm: Avoid validation of default op value lightnvm: centralize permission check for lightnvm ioctl ...
2018-03-26nvme: change namespaces_mutext to namespaces_rwsemJianchao Wang1-2/+2
namespaces_mutext is used to synchronize the operations on ctrl namespaces list. Most of the time, it is a read operation. On the other hand, there are many interfaces in nvme core that need this lock, such as nvme_wait_freeze, and even more interfaces will be added. If we use mutex here, circular dependency could be introduced easily. For example: context A context B nvme_xxx nvme_xxx hold namespaces_mutext require namespaces_mutext sync context B So it is better to change it from mutex to rwsem. Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-09block: Use blk_queue_flag_*() in drivers instead of queue_flag_*()Bart Van Assche1-1/+1
This patch has been generated as follows: for verb in set_unlocked clear_unlocked set clear; do replace-in-files queue_flag_${verb} blk_queue_flag_${verb%_unlocked} \ $(git grep -lw queue_flag_${verb} drivers block/bsg*) done Except for protecting all queue flag changes with the queue lock this patch does not change any functionality. Cc: Mike Snitzer <snitzer@redhat.com> Cc: Shaohua Li <shli@fb.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-07Revert "nvme: create 'slaves' and 'holders' entries for hidden controllers"Christoph Hellwig1-30/+0
This reverts commit e9a48034d7d1318ece7d4a235838a86c94db9d68. The slaves and holders link for the hidden gendisks confuse lsblk so that it errors out on, or doesn't report the nvme multipath devices. Given that we don't need holder relationships for something that can't even be directly accessed we should just stop creating those links. Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Potnuri Bharat Teja <bharat@chelsio.com> Cc: stable@vger.kernel.org Signed-off-by: Keith Busch <keith.busch@intel.com>
2018-02-28block: Add 'lock' as third argument to blk_alloc_queue_node()Bart Van Assche1-1/+1
This patch does not change any functionality. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-02-28nvme-multipath: fix sysfs dangerously created linksBaegjae Sung1-5/+10
If multipathing is enabled, each NVMe subsystem creates a head namespace (e.g., nvme0n1) and multiple private namespaces (e.g., nvme0c0n1 and nvme0c1n1) in sysfs. When creating links for private namespaces, links of head namespace are used, so the namespace creation order must be followed (e.g., nvme0n1 -> nvme0c1n1). If the order is not followed, links of sysfs will be incomplete or kernel panic will occur. The kernel panic was: kernel BUG at fs/sysfs/symlink.c:27! Call Trace: nvme_mpath_add_disk_links+0x5d/0x80 [nvme_core] nvme_validate_ns+0x5c2/0x850 [nvme_core] nvme_scan_work+0x1af/0x2d0 [nvme_core] Correct order Context A Context B nvme0n1 nvme0c0n1 nvme0c1n1 Incorrect order Context A Context B nvme0c1n1 nvme0n1 nvme0c0n1 The nvme_mpath_add_disk (for creating head namespace) is called just before the nvme_mpath_add_disk_links (for creating private namespaces). In nvme_mpath_add_disk, the first context acquires the lock of subsystem and creates a head namespace, and other contexts do nothing by checking GENHD_FL_UP of a head namespace after waiting to acquire the lock. We verified the code with or without multipathing using three vendors of dual-port NVMe SSDs. Signed-off-by: Baegjae Sung <baegjae@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <keith.busch@intel.com>
2018-01-10nvme/multipath: Use blk_path_errorKeith Busch1-13/+1
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>
2018-01-10nvme/multipath: Consult blk_status_t for failoverKeith Busch1-36/+8
This removes nvme multipath's specific status decoding to see if failover is needed, using the generic blk_status_t that was decoded earlier. This abstraction from the raw NVMe status means all status decoding exists in one place. 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>
2017-11-20nvme: fix spelling mistake: "requeing" -> "requeuing"Colin Ian King1-1/+1
Trivial fix to spelling mistake in dev_warn_ratelimited message text Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2017-11-11nvme: create 'slaves' and 'holders' entries for hidden controllersHannes Reinecke1-0/+30
When creating nvme multipath devices we should populate the 'slaves' and 'holders' directorys properly to aid userspace topology detection. Signed-off-by: Hannes Reinecke <hare@suse.com> [hch: split from a larger patch, compile fix for CONFIG_NVME_MULTIPATH=n] Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-11-11nvme: also expose the namespace identification sysfs files for mpath nodesChristoph Hellwig1-0/+6
We do this by adding a helper that returns the ns_head for a device that can belong to either the per-controller or per-subsystem block device nodes, and otherwise reuse all the existing code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-11-11nvme: implement multipath access to nvme subsystemsChristoph Hellwig1-0/+255
This patch adds native multipath support to the nvme driver. For each namespace we create only single block device node, which can be used to access that namespace through any of the controllers that refer to it. The gendisk for each controllers path to the name space still exists inside the kernel, but is hidden from userspace. The character device nodes are still available on a per-controller basis. A new link from the sysfs directory for the subsystem allows to find all controllers for a given subsystem. Currently we will always send I/O to the first available path, this will be changed once the NVMe Asynchronous Namespace Access (ANA) TP is ratified and implemented, at which point we will look at the ANA state for each namespace. Another possibility that was prototyped is to use the path that is closes to the submitting NUMA code, which will be mostly interesting for PCI, but might also be useful for RDMA or FC transports in the future. There is not plan to implement round robin or I/O service time path selectors, as those are not scalable with the performance rates provided by NVMe. The multipath device will go away once all paths to it disappear, any delay to keep it alive needs to be implemented at the controller level. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>