![Hannes Reinecke](/assets/img/avatar_default.png)
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>
253 lines
6.8 KiB
C
253 lines
6.8 KiB
C
/*
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* Copyright (c) 2017 Christoph Hellwig.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/moduleparam.h>
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#include <trace/events/block.h>
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#include "nvme.h"
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static bool multipath = true;
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module_param(multipath, bool, 0444);
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MODULE_PARM_DESC(multipath,
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"turn on native support for multiple controllers per subsystem");
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/*
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* If multipathing is enabled we need to always use the subsystem instance
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* number for numbering our devices to avoid conflicts between subsystems that
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* have multiple controllers and thus use the multipath-aware subsystem node
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* and those that have a single controller and use the controller node
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* directly.
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*/
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void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
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struct nvme_ctrl *ctrl, int *flags)
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{
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if (!multipath) {
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sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
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} else if (ns->head->disk) {
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sprintf(disk_name, "nvme%dc%dn%d", ctrl->subsys->instance,
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ctrl->cntlid, ns->head->instance);
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*flags = GENHD_FL_HIDDEN;
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} else {
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sprintf(disk_name, "nvme%dn%d", ctrl->subsys->instance,
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ns->head->instance);
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}
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}
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void nvme_failover_req(struct request *req)
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{
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struct nvme_ns *ns = req->q->queuedata;
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unsigned long flags;
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spin_lock_irqsave(&ns->head->requeue_lock, flags);
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blk_steal_bios(&ns->head->requeue_list, req);
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spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
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blk_mq_end_request(req, 0);
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nvme_reset_ctrl(ns->ctrl);
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kblockd_schedule_work(&ns->head->requeue_work);
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}
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bool nvme_req_needs_failover(struct request *req, blk_status_t error)
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{
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if (!(req->cmd_flags & REQ_NVME_MPATH))
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return false;
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return blk_path_error(error);
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}
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void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
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{
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struct nvme_ns *ns;
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down_read(&ctrl->namespaces_rwsem);
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list_for_each_entry(ns, &ctrl->namespaces, list) {
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if (ns->head->disk)
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kblockd_schedule_work(&ns->head->requeue_work);
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}
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up_read(&ctrl->namespaces_rwsem);
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}
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static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head)
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{
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struct nvme_ns *ns;
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list_for_each_entry_rcu(ns, &head->list, siblings) {
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if (ns->ctrl->state == NVME_CTRL_LIVE) {
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rcu_assign_pointer(head->current_path, ns);
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return ns;
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}
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}
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return NULL;
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}
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inline struct nvme_ns *nvme_find_path(struct nvme_ns_head *head)
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{
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struct nvme_ns *ns = srcu_dereference(head->current_path, &head->srcu);
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if (unlikely(!ns || ns->ctrl->state != NVME_CTRL_LIVE))
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ns = __nvme_find_path(head);
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return ns;
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}
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static blk_qc_t nvme_ns_head_make_request(struct request_queue *q,
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struct bio *bio)
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{
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struct nvme_ns_head *head = q->queuedata;
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struct device *dev = disk_to_dev(head->disk);
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struct nvme_ns *ns;
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blk_qc_t ret = BLK_QC_T_NONE;
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int srcu_idx;
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srcu_idx = srcu_read_lock(&head->srcu);
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ns = nvme_find_path(head);
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if (likely(ns)) {
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bio->bi_disk = ns->disk;
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bio->bi_opf |= REQ_NVME_MPATH;
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trace_block_bio_remap(bio->bi_disk->queue, bio,
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disk_devt(ns->head->disk),
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bio->bi_iter.bi_sector);
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ret = direct_make_request(bio);
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} else if (!list_empty_careful(&head->list)) {
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dev_warn_ratelimited(dev, "no path available - requeuing I/O\n");
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spin_lock_irq(&head->requeue_lock);
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bio_list_add(&head->requeue_list, bio);
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spin_unlock_irq(&head->requeue_lock);
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} else {
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dev_warn_ratelimited(dev, "no path - failing I/O\n");
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bio->bi_status = BLK_STS_IOERR;
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bio_endio(bio);
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}
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srcu_read_unlock(&head->srcu, srcu_idx);
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return ret;
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}
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static bool nvme_ns_head_poll(struct request_queue *q, blk_qc_t qc)
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{
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struct nvme_ns_head *head = q->queuedata;
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struct nvme_ns *ns;
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bool found = false;
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int srcu_idx;
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srcu_idx = srcu_read_lock(&head->srcu);
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ns = srcu_dereference(head->current_path, &head->srcu);
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if (likely(ns && ns->ctrl->state == NVME_CTRL_LIVE))
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found = ns->queue->poll_fn(q, qc);
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srcu_read_unlock(&head->srcu, srcu_idx);
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return found;
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}
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static void nvme_requeue_work(struct work_struct *work)
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{
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struct nvme_ns_head *head =
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container_of(work, struct nvme_ns_head, requeue_work);
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struct bio *bio, *next;
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spin_lock_irq(&head->requeue_lock);
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next = bio_list_get(&head->requeue_list);
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spin_unlock_irq(&head->requeue_lock);
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while ((bio = next) != NULL) {
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next = bio->bi_next;
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bio->bi_next = NULL;
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/*
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* Reset disk to the mpath node and resubmit to select a new
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* path.
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*/
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bio->bi_disk = head->disk;
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generic_make_request(bio);
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}
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}
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int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
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{
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struct request_queue *q;
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bool vwc = false;
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bio_list_init(&head->requeue_list);
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spin_lock_init(&head->requeue_lock);
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INIT_WORK(&head->requeue_work, nvme_requeue_work);
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/*
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* Add a multipath node if the subsystems supports multiple controllers.
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* We also do this for private namespaces as the namespace sharing data could
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* change after a rescan.
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*/
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if (!(ctrl->subsys->cmic & (1 << 1)) || !multipath)
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return 0;
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q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, NULL);
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if (!q)
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goto out;
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q->queuedata = head;
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blk_queue_make_request(q, nvme_ns_head_make_request);
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q->poll_fn = nvme_ns_head_poll;
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blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
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/* set to a default value for 512 until disk is validated */
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blk_queue_logical_block_size(q, 512);
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/* we need to propagate up the VMC settings */
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if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
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vwc = true;
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blk_queue_write_cache(q, vwc, vwc);
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head->disk = alloc_disk(0);
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if (!head->disk)
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goto out_cleanup_queue;
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head->disk->fops = &nvme_ns_head_ops;
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head->disk->private_data = head;
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head->disk->queue = q;
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head->disk->flags = GENHD_FL_EXT_DEVT;
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sprintf(head->disk->disk_name, "nvme%dn%d",
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ctrl->subsys->instance, head->instance);
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return 0;
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out_cleanup_queue:
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blk_cleanup_queue(q);
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out:
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return -ENOMEM;
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}
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void nvme_mpath_add_disk(struct nvme_ns_head *head)
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{
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if (!head->disk)
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return;
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mutex_lock(&head->subsys->lock);
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if (!(head->disk->flags & GENHD_FL_UP)) {
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device_add_disk(&head->subsys->dev, head->disk);
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if (sysfs_create_group(&disk_to_dev(head->disk)->kobj,
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&nvme_ns_id_attr_group))
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pr_warn("%s: failed to create sysfs group for identification\n",
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head->disk->disk_name);
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}
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mutex_unlock(&head->subsys->lock);
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}
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void nvme_mpath_remove_disk(struct nvme_ns_head *head)
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{
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if (!head->disk)
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return;
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sysfs_remove_group(&disk_to_dev(head->disk)->kobj,
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&nvme_ns_id_attr_group);
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del_gendisk(head->disk);
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blk_set_queue_dying(head->disk->queue);
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/* make sure all pending bios are cleaned up */
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kblockd_schedule_work(&head->requeue_work);
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flush_work(&head->requeue_work);
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blk_cleanup_queue(head->disk->queue);
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put_disk(head->disk);
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}
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