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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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2050 lines
49 KiB
C
2050 lines
49 KiB
C
/*
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* Copyright (C) 2003 Sistina Software Limited.
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* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include <linux/device-mapper.h>
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#include "dm-rq.h"
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#include "dm-bio-record.h"
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#include "dm-path-selector.h"
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#include "dm-uevent.h"
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#include <linux/blkdev.h>
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/mempool.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/workqueue.h>
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#include <linux/delay.h>
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#include <scsi/scsi_dh.h>
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#include <linux/atomic.h>
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#include <linux/blk-mq.h>
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#define DM_MSG_PREFIX "multipath"
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#define DM_PG_INIT_DELAY_MSECS 2000
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#define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1)
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/* Path properties */
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struct pgpath {
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struct list_head list;
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struct priority_group *pg; /* Owning PG */
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unsigned fail_count; /* Cumulative failure count */
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struct dm_path path;
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struct delayed_work activate_path;
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bool is_active:1; /* Path status */
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};
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#define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
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/*
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* Paths are grouped into Priority Groups and numbered from 1 upwards.
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* Each has a path selector which controls which path gets used.
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*/
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struct priority_group {
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struct list_head list;
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struct multipath *m; /* Owning multipath instance */
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struct path_selector ps;
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unsigned pg_num; /* Reference number */
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unsigned nr_pgpaths; /* Number of paths in PG */
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struct list_head pgpaths;
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bool bypassed:1; /* Temporarily bypass this PG? */
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};
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/* Multipath context */
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struct multipath {
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struct list_head list;
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struct dm_target *ti;
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const char *hw_handler_name;
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char *hw_handler_params;
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spinlock_t lock;
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unsigned nr_priority_groups;
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struct list_head priority_groups;
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wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */
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struct pgpath *current_pgpath;
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struct priority_group *current_pg;
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struct priority_group *next_pg; /* Switch to this PG if set */
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unsigned long flags; /* Multipath state flags */
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unsigned pg_init_retries; /* Number of times to retry pg_init */
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unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */
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atomic_t nr_valid_paths; /* Total number of usable paths */
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atomic_t pg_init_in_progress; /* Only one pg_init allowed at once */
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atomic_t pg_init_count; /* Number of times pg_init called */
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unsigned queue_mode;
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struct mutex work_mutex;
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struct work_struct trigger_event;
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struct work_struct process_queued_bios;
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struct bio_list queued_bios;
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};
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/*
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* Context information attached to each io we process.
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*/
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struct dm_mpath_io {
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struct pgpath *pgpath;
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size_t nr_bytes;
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};
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typedef int (*action_fn) (struct pgpath *pgpath);
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static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
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static void trigger_event(struct work_struct *work);
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static void activate_path(struct work_struct *work);
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static void process_queued_bios(struct work_struct *work);
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/*-----------------------------------------------
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* Multipath state flags.
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*-----------------------------------------------*/
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#define MPATHF_QUEUE_IO 0 /* Must we queue all I/O? */
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#define MPATHF_QUEUE_IF_NO_PATH 1 /* Queue I/O if last path fails? */
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#define MPATHF_SAVED_QUEUE_IF_NO_PATH 2 /* Saved state during suspension */
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#define MPATHF_RETAIN_ATTACHED_HW_HANDLER 3 /* If there's already a hw_handler present, don't change it. */
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#define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */
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#define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */
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#define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */
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/*-----------------------------------------------
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* Allocation routines
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*-----------------------------------------------*/
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static struct pgpath *alloc_pgpath(void)
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{
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struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
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if (pgpath) {
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pgpath->is_active = true;
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INIT_DELAYED_WORK(&pgpath->activate_path, activate_path);
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}
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return pgpath;
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}
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static void free_pgpath(struct pgpath *pgpath)
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{
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kfree(pgpath);
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}
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static struct priority_group *alloc_priority_group(void)
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{
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struct priority_group *pg;
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pg = kzalloc(sizeof(*pg), GFP_KERNEL);
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if (pg)
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INIT_LIST_HEAD(&pg->pgpaths);
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return pg;
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}
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static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
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{
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struct pgpath *pgpath, *tmp;
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list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
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list_del(&pgpath->list);
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dm_put_device(ti, pgpath->path.dev);
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free_pgpath(pgpath);
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}
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}
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static void free_priority_group(struct priority_group *pg,
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struct dm_target *ti)
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{
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struct path_selector *ps = &pg->ps;
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if (ps->type) {
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ps->type->destroy(ps);
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dm_put_path_selector(ps->type);
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}
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free_pgpaths(&pg->pgpaths, ti);
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kfree(pg);
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}
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static struct multipath *alloc_multipath(struct dm_target *ti)
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{
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struct multipath *m;
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m = kzalloc(sizeof(*m), GFP_KERNEL);
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if (m) {
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INIT_LIST_HEAD(&m->priority_groups);
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spin_lock_init(&m->lock);
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set_bit(MPATHF_QUEUE_IO, &m->flags);
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atomic_set(&m->nr_valid_paths, 0);
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atomic_set(&m->pg_init_in_progress, 0);
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atomic_set(&m->pg_init_count, 0);
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m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
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INIT_WORK(&m->trigger_event, trigger_event);
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init_waitqueue_head(&m->pg_init_wait);
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mutex_init(&m->work_mutex);
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m->queue_mode = DM_TYPE_NONE;
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m->ti = ti;
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ti->private = m;
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}
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return m;
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}
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static int alloc_multipath_stage2(struct dm_target *ti, struct multipath *m)
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{
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if (m->queue_mode == DM_TYPE_NONE) {
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/*
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* Default to request-based.
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*/
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if (dm_use_blk_mq(dm_table_get_md(ti->table)))
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m->queue_mode = DM_TYPE_MQ_REQUEST_BASED;
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else
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m->queue_mode = DM_TYPE_REQUEST_BASED;
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} else if (m->queue_mode == DM_TYPE_BIO_BASED) {
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INIT_WORK(&m->process_queued_bios, process_queued_bios);
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/*
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* bio-based doesn't support any direct scsi_dh management;
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* it just discovers if a scsi_dh is attached.
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*/
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set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags);
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}
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dm_table_set_type(ti->table, m->queue_mode);
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return 0;
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}
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static void free_multipath(struct multipath *m)
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{
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struct priority_group *pg, *tmp;
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list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
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list_del(&pg->list);
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free_priority_group(pg, m->ti);
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}
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kfree(m->hw_handler_name);
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kfree(m->hw_handler_params);
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kfree(m);
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}
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static struct dm_mpath_io *get_mpio(union map_info *info)
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{
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return info->ptr;
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}
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static size_t multipath_per_bio_data_size(void)
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{
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return sizeof(struct dm_mpath_io) + sizeof(struct dm_bio_details);
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}
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static struct dm_mpath_io *get_mpio_from_bio(struct bio *bio)
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{
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return dm_per_bio_data(bio, multipath_per_bio_data_size());
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}
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static struct dm_bio_details *get_bio_details_from_bio(struct bio *bio)
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{
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/* dm_bio_details is immediately after the dm_mpath_io in bio's per-bio-data */
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struct dm_mpath_io *mpio = get_mpio_from_bio(bio);
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void *bio_details = mpio + 1;
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return bio_details;
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}
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static void multipath_init_per_bio_data(struct bio *bio, struct dm_mpath_io **mpio_p,
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struct dm_bio_details **bio_details_p)
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{
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struct dm_mpath_io *mpio = get_mpio_from_bio(bio);
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struct dm_bio_details *bio_details = get_bio_details_from_bio(bio);
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memset(mpio, 0, sizeof(*mpio));
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memset(bio_details, 0, sizeof(*bio_details));
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dm_bio_record(bio_details, bio);
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if (mpio_p)
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*mpio_p = mpio;
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if (bio_details_p)
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*bio_details_p = bio_details;
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}
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/*-----------------------------------------------
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* Path selection
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*-----------------------------------------------*/
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static int __pg_init_all_paths(struct multipath *m)
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{
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struct pgpath *pgpath;
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unsigned long pg_init_delay = 0;
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if (atomic_read(&m->pg_init_in_progress) || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags))
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return 0;
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atomic_inc(&m->pg_init_count);
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clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
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/* Check here to reset pg_init_required */
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if (!m->current_pg)
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return 0;
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if (test_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags))
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pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ?
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m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS);
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list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) {
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/* Skip failed paths */
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if (!pgpath->is_active)
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continue;
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if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path,
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pg_init_delay))
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atomic_inc(&m->pg_init_in_progress);
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}
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return atomic_read(&m->pg_init_in_progress);
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}
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static void pg_init_all_paths(struct multipath *m)
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{
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unsigned long flags;
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spin_lock_irqsave(&m->lock, flags);
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__pg_init_all_paths(m);
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spin_unlock_irqrestore(&m->lock, flags);
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}
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static void __switch_pg(struct multipath *m, struct priority_group *pg)
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{
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m->current_pg = pg;
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/* Must we initialise the PG first, and queue I/O till it's ready? */
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if (m->hw_handler_name) {
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set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
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set_bit(MPATHF_QUEUE_IO, &m->flags);
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} else {
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clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
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clear_bit(MPATHF_QUEUE_IO, &m->flags);
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}
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atomic_set(&m->pg_init_count, 0);
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}
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static struct pgpath *choose_path_in_pg(struct multipath *m,
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struct priority_group *pg,
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size_t nr_bytes)
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{
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unsigned long flags;
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struct dm_path *path;
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struct pgpath *pgpath;
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path = pg->ps.type->select_path(&pg->ps, nr_bytes);
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if (!path)
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return ERR_PTR(-ENXIO);
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pgpath = path_to_pgpath(path);
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if (unlikely(lockless_dereference(m->current_pg) != pg)) {
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/* Only update current_pgpath if pg changed */
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spin_lock_irqsave(&m->lock, flags);
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m->current_pgpath = pgpath;
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__switch_pg(m, pg);
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spin_unlock_irqrestore(&m->lock, flags);
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}
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return pgpath;
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}
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static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
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{
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unsigned long flags;
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struct priority_group *pg;
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struct pgpath *pgpath;
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unsigned bypassed = 1;
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if (!atomic_read(&m->nr_valid_paths)) {
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clear_bit(MPATHF_QUEUE_IO, &m->flags);
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goto failed;
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}
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/* Were we instructed to switch PG? */
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if (lockless_dereference(m->next_pg)) {
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spin_lock_irqsave(&m->lock, flags);
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pg = m->next_pg;
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if (!pg) {
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spin_unlock_irqrestore(&m->lock, flags);
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goto check_current_pg;
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}
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m->next_pg = NULL;
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spin_unlock_irqrestore(&m->lock, flags);
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pgpath = choose_path_in_pg(m, pg, nr_bytes);
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if (!IS_ERR_OR_NULL(pgpath))
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return pgpath;
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}
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/* Don't change PG until it has no remaining paths */
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check_current_pg:
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pg = lockless_dereference(m->current_pg);
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if (pg) {
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pgpath = choose_path_in_pg(m, pg, nr_bytes);
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if (!IS_ERR_OR_NULL(pgpath))
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return pgpath;
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}
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/*
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* Loop through priority groups until we find a valid path.
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* First time we skip PGs marked 'bypassed'.
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* Second time we only try the ones we skipped, but set
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* pg_init_delay_retry so we do not hammer controllers.
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*/
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do {
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list_for_each_entry(pg, &m->priority_groups, list) {
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if (pg->bypassed == !!bypassed)
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continue;
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pgpath = choose_path_in_pg(m, pg, nr_bytes);
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if (!IS_ERR_OR_NULL(pgpath)) {
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if (!bypassed)
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set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
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return pgpath;
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}
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}
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} while (bypassed--);
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failed:
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spin_lock_irqsave(&m->lock, flags);
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m->current_pgpath = NULL;
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m->current_pg = NULL;
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spin_unlock_irqrestore(&m->lock, flags);
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return NULL;
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}
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/*
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* Check whether bios must be queued in the device-mapper core rather
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* than here in the target.
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*
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* If m->queue_if_no_path and m->saved_queue_if_no_path hold the
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* same value then we are not between multipath_presuspend()
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* and multipath_resume() calls and we have no need to check
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* for the DMF_NOFLUSH_SUSPENDING flag.
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*/
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static bool __must_push_back(struct multipath *m)
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{
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return ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) !=
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test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) &&
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dm_noflush_suspending(m->ti));
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}
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static bool must_push_back_rq(struct multipath *m)
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{
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bool r;
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unsigned long flags;
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spin_lock_irqsave(&m->lock, flags);
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r = (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) ||
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__must_push_back(m));
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spin_unlock_irqrestore(&m->lock, flags);
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return r;
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}
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static bool must_push_back_bio(struct multipath *m)
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{
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bool r;
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unsigned long flags;
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spin_lock_irqsave(&m->lock, flags);
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r = __must_push_back(m);
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spin_unlock_irqrestore(&m->lock, flags);
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return r;
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}
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/*
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* Map cloned requests (request-based multipath)
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*/
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static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
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union map_info *map_context,
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struct request **__clone)
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{
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struct multipath *m = ti->private;
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int r = DM_MAPIO_REQUEUE;
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size_t nr_bytes = blk_rq_bytes(rq);
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struct pgpath *pgpath;
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struct block_device *bdev;
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struct dm_mpath_io *mpio = get_mpio(map_context);
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struct request *clone;
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/* Do we need to select a new pgpath? */
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pgpath = lockless_dereference(m->current_pgpath);
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if (!pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags))
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pgpath = choose_pgpath(m, nr_bytes);
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if (!pgpath) {
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if (must_push_back_rq(m))
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return DM_MAPIO_DELAY_REQUEUE;
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return -EIO; /* Failed */
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} else if (test_bit(MPATHF_QUEUE_IO, &m->flags) ||
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test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) {
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pg_init_all_paths(m);
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return r;
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}
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memset(mpio, 0, sizeof(*mpio));
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mpio->pgpath = pgpath;
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mpio->nr_bytes = nr_bytes;
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bdev = pgpath->path.dev->bdev;
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clone = blk_get_request(bdev_get_queue(bdev),
|
|
rq->cmd_flags | REQ_NOMERGE,
|
|
GFP_ATOMIC);
|
|
if (IS_ERR(clone)) {
|
|
/* EBUSY, ENODEV or EWOULDBLOCK: requeue */
|
|
return r;
|
|
}
|
|
clone->bio = clone->biotail = NULL;
|
|
clone->rq_disk = bdev->bd_disk;
|
|
clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
|
|
*__clone = clone;
|
|
|
|
if (pgpath->pg->ps.type->start_io)
|
|
pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
|
|
&pgpath->path,
|
|
nr_bytes);
|
|
return DM_MAPIO_REMAPPED;
|
|
}
|
|
|
|
static void multipath_release_clone(struct request *clone)
|
|
{
|
|
blk_put_request(clone);
|
|
}
|
|
|
|
/*
|
|
* Map cloned bios (bio-based multipath)
|
|
*/
|
|
static int __multipath_map_bio(struct multipath *m, struct bio *bio, struct dm_mpath_io *mpio)
|
|
{
|
|
size_t nr_bytes = bio->bi_iter.bi_size;
|
|
struct pgpath *pgpath;
|
|
unsigned long flags;
|
|
bool queue_io;
|
|
|
|
/* Do we need to select a new pgpath? */
|
|
pgpath = lockless_dereference(m->current_pgpath);
|
|
queue_io = test_bit(MPATHF_QUEUE_IO, &m->flags);
|
|
if (!pgpath || !queue_io)
|
|
pgpath = choose_pgpath(m, nr_bytes);
|
|
|
|
if ((pgpath && queue_io) ||
|
|
(!pgpath && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) {
|
|
/* Queue for the daemon to resubmit */
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
bio_list_add(&m->queued_bios, bio);
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
/* PG_INIT_REQUIRED cannot be set without QUEUE_IO */
|
|
if (queue_io || test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
|
|
pg_init_all_paths(m);
|
|
else if (!queue_io)
|
|
queue_work(kmultipathd, &m->process_queued_bios);
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
if (!pgpath) {
|
|
if (!must_push_back_bio(m))
|
|
return -EIO;
|
|
return DM_MAPIO_REQUEUE;
|
|
}
|
|
|
|
mpio->pgpath = pgpath;
|
|
mpio->nr_bytes = nr_bytes;
|
|
|
|
bio->bi_error = 0;
|
|
bio->bi_bdev = pgpath->path.dev->bdev;
|
|
bio->bi_opf |= REQ_FAILFAST_TRANSPORT;
|
|
|
|
if (pgpath->pg->ps.type->start_io)
|
|
pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
|
|
&pgpath->path,
|
|
nr_bytes);
|
|
return DM_MAPIO_REMAPPED;
|
|
}
|
|
|
|
static int multipath_map_bio(struct dm_target *ti, struct bio *bio)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
struct dm_mpath_io *mpio = NULL;
|
|
|
|
multipath_init_per_bio_data(bio, &mpio, NULL);
|
|
|
|
return __multipath_map_bio(m, bio, mpio);
|
|
}
|
|
|
|
static void process_queued_io_list(struct multipath *m)
|
|
{
|
|
if (m->queue_mode == DM_TYPE_MQ_REQUEST_BASED)
|
|
dm_mq_kick_requeue_list(dm_table_get_md(m->ti->table));
|
|
else if (m->queue_mode == DM_TYPE_BIO_BASED)
|
|
queue_work(kmultipathd, &m->process_queued_bios);
|
|
}
|
|
|
|
static void process_queued_bios(struct work_struct *work)
|
|
{
|
|
int r;
|
|
unsigned long flags;
|
|
struct bio *bio;
|
|
struct bio_list bios;
|
|
struct blk_plug plug;
|
|
struct multipath *m =
|
|
container_of(work, struct multipath, process_queued_bios);
|
|
|
|
bio_list_init(&bios);
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (bio_list_empty(&m->queued_bios)) {
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
return;
|
|
}
|
|
|
|
bio_list_merge(&bios, &m->queued_bios);
|
|
bio_list_init(&m->queued_bios);
|
|
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
blk_start_plug(&plug);
|
|
while ((bio = bio_list_pop(&bios))) {
|
|
r = __multipath_map_bio(m, bio, get_mpio_from_bio(bio));
|
|
if (r < 0 || r == DM_MAPIO_REQUEUE) {
|
|
bio->bi_error = r;
|
|
bio_endio(bio);
|
|
} else if (r == DM_MAPIO_REMAPPED)
|
|
generic_make_request(bio);
|
|
}
|
|
blk_finish_plug(&plug);
|
|
}
|
|
|
|
/*
|
|
* If we run out of usable paths, should we queue I/O or error it?
|
|
*/
|
|
static int queue_if_no_path(struct multipath *m, bool queue_if_no_path,
|
|
bool save_old_value)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (save_old_value) {
|
|
if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
|
|
set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);
|
|
else
|
|
clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);
|
|
} else {
|
|
if (queue_if_no_path)
|
|
set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);
|
|
else
|
|
clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags);
|
|
}
|
|
if (queue_if_no_path)
|
|
set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
|
|
else
|
|
clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
|
|
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
if (!queue_if_no_path) {
|
|
dm_table_run_md_queue_async(m->ti->table);
|
|
process_queued_io_list(m);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* An event is triggered whenever a path is taken out of use.
|
|
* Includes path failure and PG bypass.
|
|
*/
|
|
static void trigger_event(struct work_struct *work)
|
|
{
|
|
struct multipath *m =
|
|
container_of(work, struct multipath, trigger_event);
|
|
|
|
dm_table_event(m->ti->table);
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Constructor/argument parsing:
|
|
* <#multipath feature args> [<arg>]*
|
|
* <#hw_handler args> [hw_handler [<arg>]*]
|
|
* <#priority groups>
|
|
* <initial priority group>
|
|
* [<selector> <#selector args> [<arg>]*
|
|
* <#paths> <#per-path selector args>
|
|
* [<path> [<arg>]* ]+ ]+
|
|
*---------------------------------------------------------------*/
|
|
static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
|
|
struct dm_target *ti)
|
|
{
|
|
int r;
|
|
struct path_selector_type *pst;
|
|
unsigned ps_argc;
|
|
|
|
static struct dm_arg _args[] = {
|
|
{0, 1024, "invalid number of path selector args"},
|
|
};
|
|
|
|
pst = dm_get_path_selector(dm_shift_arg(as));
|
|
if (!pst) {
|
|
ti->error = "unknown path selector type";
|
|
return -EINVAL;
|
|
}
|
|
|
|
r = dm_read_arg_group(_args, as, &ps_argc, &ti->error);
|
|
if (r) {
|
|
dm_put_path_selector(pst);
|
|
return -EINVAL;
|
|
}
|
|
|
|
r = pst->create(&pg->ps, ps_argc, as->argv);
|
|
if (r) {
|
|
dm_put_path_selector(pst);
|
|
ti->error = "path selector constructor failed";
|
|
return r;
|
|
}
|
|
|
|
pg->ps.type = pst;
|
|
dm_consume_args(as, ps_argc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
|
|
struct dm_target *ti)
|
|
{
|
|
int r;
|
|
struct pgpath *p;
|
|
struct multipath *m = ti->private;
|
|
struct request_queue *q = NULL;
|
|
const char *attached_handler_name;
|
|
|
|
/* we need at least a path arg */
|
|
if (as->argc < 1) {
|
|
ti->error = "no device given";
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
p = alloc_pgpath();
|
|
if (!p)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
|
|
&p->path.dev);
|
|
if (r) {
|
|
ti->error = "error getting device";
|
|
goto bad;
|
|
}
|
|
|
|
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) || m->hw_handler_name)
|
|
q = bdev_get_queue(p->path.dev->bdev);
|
|
|
|
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) {
|
|
retain:
|
|
attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
|
|
if (attached_handler_name) {
|
|
/*
|
|
* Clear any hw_handler_params associated with a
|
|
* handler that isn't already attached.
|
|
*/
|
|
if (m->hw_handler_name && strcmp(attached_handler_name, m->hw_handler_name)) {
|
|
kfree(m->hw_handler_params);
|
|
m->hw_handler_params = NULL;
|
|
}
|
|
|
|
/*
|
|
* Reset hw_handler_name to match the attached handler
|
|
*
|
|
* NB. This modifies the table line to show the actual
|
|
* handler instead of the original table passed in.
|
|
*/
|
|
kfree(m->hw_handler_name);
|
|
m->hw_handler_name = attached_handler_name;
|
|
}
|
|
}
|
|
|
|
if (m->hw_handler_name) {
|
|
r = scsi_dh_attach(q, m->hw_handler_name);
|
|
if (r == -EBUSY) {
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
printk(KERN_INFO "dm-mpath: retaining handler on device %s\n",
|
|
bdevname(p->path.dev->bdev, b));
|
|
goto retain;
|
|
}
|
|
if (r < 0) {
|
|
ti->error = "error attaching hardware handler";
|
|
dm_put_device(ti, p->path.dev);
|
|
goto bad;
|
|
}
|
|
|
|
if (m->hw_handler_params) {
|
|
r = scsi_dh_set_params(q, m->hw_handler_params);
|
|
if (r < 0) {
|
|
ti->error = "unable to set hardware "
|
|
"handler parameters";
|
|
dm_put_device(ti, p->path.dev);
|
|
goto bad;
|
|
}
|
|
}
|
|
}
|
|
|
|
r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
|
|
if (r) {
|
|
dm_put_device(ti, p->path.dev);
|
|
goto bad;
|
|
}
|
|
|
|
return p;
|
|
|
|
bad:
|
|
free_pgpath(p);
|
|
return ERR_PTR(r);
|
|
}
|
|
|
|
static struct priority_group *parse_priority_group(struct dm_arg_set *as,
|
|
struct multipath *m)
|
|
{
|
|
static struct dm_arg _args[] = {
|
|
{1, 1024, "invalid number of paths"},
|
|
{0, 1024, "invalid number of selector args"}
|
|
};
|
|
|
|
int r;
|
|
unsigned i, nr_selector_args, nr_args;
|
|
struct priority_group *pg;
|
|
struct dm_target *ti = m->ti;
|
|
|
|
if (as->argc < 2) {
|
|
as->argc = 0;
|
|
ti->error = "not enough priority group arguments";
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
pg = alloc_priority_group();
|
|
if (!pg) {
|
|
ti->error = "couldn't allocate priority group";
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
pg->m = m;
|
|
|
|
r = parse_path_selector(as, pg, ti);
|
|
if (r)
|
|
goto bad;
|
|
|
|
/*
|
|
* read the paths
|
|
*/
|
|
r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
nr_args = 1 + nr_selector_args;
|
|
for (i = 0; i < pg->nr_pgpaths; i++) {
|
|
struct pgpath *pgpath;
|
|
struct dm_arg_set path_args;
|
|
|
|
if (as->argc < nr_args) {
|
|
ti->error = "not enough path parameters";
|
|
r = -EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
path_args.argc = nr_args;
|
|
path_args.argv = as->argv;
|
|
|
|
pgpath = parse_path(&path_args, &pg->ps, ti);
|
|
if (IS_ERR(pgpath)) {
|
|
r = PTR_ERR(pgpath);
|
|
goto bad;
|
|
}
|
|
|
|
pgpath->pg = pg;
|
|
list_add_tail(&pgpath->list, &pg->pgpaths);
|
|
dm_consume_args(as, nr_args);
|
|
}
|
|
|
|
return pg;
|
|
|
|
bad:
|
|
free_priority_group(pg, ti);
|
|
return ERR_PTR(r);
|
|
}
|
|
|
|
static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
|
|
{
|
|
unsigned hw_argc;
|
|
int ret;
|
|
struct dm_target *ti = m->ti;
|
|
|
|
static struct dm_arg _args[] = {
|
|
{0, 1024, "invalid number of hardware handler args"},
|
|
};
|
|
|
|
if (dm_read_arg_group(_args, as, &hw_argc, &ti->error))
|
|
return -EINVAL;
|
|
|
|
if (!hw_argc)
|
|
return 0;
|
|
|
|
if (m->queue_mode == DM_TYPE_BIO_BASED) {
|
|
dm_consume_args(as, hw_argc);
|
|
DMERR("bio-based multipath doesn't allow hardware handler args");
|
|
return 0;
|
|
}
|
|
|
|
m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
|
|
if (!m->hw_handler_name)
|
|
return -EINVAL;
|
|
|
|
if (hw_argc > 1) {
|
|
char *p;
|
|
int i, j, len = 4;
|
|
|
|
for (i = 0; i <= hw_argc - 2; i++)
|
|
len += strlen(as->argv[i]) + 1;
|
|
p = m->hw_handler_params = kzalloc(len, GFP_KERNEL);
|
|
if (!p) {
|
|
ti->error = "memory allocation failed";
|
|
ret = -ENOMEM;
|
|
goto fail;
|
|
}
|
|
j = sprintf(p, "%d", hw_argc - 1);
|
|
for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1)
|
|
j = sprintf(p, "%s", as->argv[i]);
|
|
}
|
|
dm_consume_args(as, hw_argc - 1);
|
|
|
|
return 0;
|
|
fail:
|
|
kfree(m->hw_handler_name);
|
|
m->hw_handler_name = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static int parse_features(struct dm_arg_set *as, struct multipath *m)
|
|
{
|
|
int r;
|
|
unsigned argc;
|
|
struct dm_target *ti = m->ti;
|
|
const char *arg_name;
|
|
|
|
static struct dm_arg _args[] = {
|
|
{0, 8, "invalid number of feature args"},
|
|
{1, 50, "pg_init_retries must be between 1 and 50"},
|
|
{0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
|
|
};
|
|
|
|
r = dm_read_arg_group(_args, as, &argc, &ti->error);
|
|
if (r)
|
|
return -EINVAL;
|
|
|
|
if (!argc)
|
|
return 0;
|
|
|
|
do {
|
|
arg_name = dm_shift_arg(as);
|
|
argc--;
|
|
|
|
if (!strcasecmp(arg_name, "queue_if_no_path")) {
|
|
r = queue_if_no_path(m, true, false);
|
|
continue;
|
|
}
|
|
|
|
if (!strcasecmp(arg_name, "retain_attached_hw_handler")) {
|
|
set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags);
|
|
continue;
|
|
}
|
|
|
|
if (!strcasecmp(arg_name, "pg_init_retries") &&
|
|
(argc >= 1)) {
|
|
r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
|
|
argc--;
|
|
continue;
|
|
}
|
|
|
|
if (!strcasecmp(arg_name, "pg_init_delay_msecs") &&
|
|
(argc >= 1)) {
|
|
r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error);
|
|
argc--;
|
|
continue;
|
|
}
|
|
|
|
if (!strcasecmp(arg_name, "queue_mode") &&
|
|
(argc >= 1)) {
|
|
const char *queue_mode_name = dm_shift_arg(as);
|
|
|
|
if (!strcasecmp(queue_mode_name, "bio"))
|
|
m->queue_mode = DM_TYPE_BIO_BASED;
|
|
else if (!strcasecmp(queue_mode_name, "rq"))
|
|
m->queue_mode = DM_TYPE_REQUEST_BASED;
|
|
else if (!strcasecmp(queue_mode_name, "mq"))
|
|
m->queue_mode = DM_TYPE_MQ_REQUEST_BASED;
|
|
else {
|
|
ti->error = "Unknown 'queue_mode' requested";
|
|
r = -EINVAL;
|
|
}
|
|
argc--;
|
|
continue;
|
|
}
|
|
|
|
ti->error = "Unrecognised multipath feature request";
|
|
r = -EINVAL;
|
|
} while (argc && !r);
|
|
|
|
return r;
|
|
}
|
|
|
|
static int multipath_ctr(struct dm_target *ti, unsigned argc, char **argv)
|
|
{
|
|
/* target arguments */
|
|
static struct dm_arg _args[] = {
|
|
{0, 1024, "invalid number of priority groups"},
|
|
{0, 1024, "invalid initial priority group number"},
|
|
};
|
|
|
|
int r;
|
|
struct multipath *m;
|
|
struct dm_arg_set as;
|
|
unsigned pg_count = 0;
|
|
unsigned next_pg_num;
|
|
|
|
as.argc = argc;
|
|
as.argv = argv;
|
|
|
|
m = alloc_multipath(ti);
|
|
if (!m) {
|
|
ti->error = "can't allocate multipath";
|
|
return -EINVAL;
|
|
}
|
|
|
|
r = parse_features(&as, m);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = alloc_multipath_stage2(ti, m);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = parse_hw_handler(&as, m);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
if ((!m->nr_priority_groups && next_pg_num) ||
|
|
(m->nr_priority_groups && !next_pg_num)) {
|
|
ti->error = "invalid initial priority group";
|
|
r = -EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
/* parse the priority groups */
|
|
while (as.argc) {
|
|
struct priority_group *pg;
|
|
unsigned nr_valid_paths = atomic_read(&m->nr_valid_paths);
|
|
|
|
pg = parse_priority_group(&as, m);
|
|
if (IS_ERR(pg)) {
|
|
r = PTR_ERR(pg);
|
|
goto bad;
|
|
}
|
|
|
|
nr_valid_paths += pg->nr_pgpaths;
|
|
atomic_set(&m->nr_valid_paths, nr_valid_paths);
|
|
|
|
list_add_tail(&pg->list, &m->priority_groups);
|
|
pg_count++;
|
|
pg->pg_num = pg_count;
|
|
if (!--next_pg_num)
|
|
m->next_pg = pg;
|
|
}
|
|
|
|
if (pg_count != m->nr_priority_groups) {
|
|
ti->error = "priority group count mismatch";
|
|
r = -EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
ti->num_flush_bios = 1;
|
|
ti->num_discard_bios = 1;
|
|
ti->num_write_same_bios = 1;
|
|
if (m->queue_mode == DM_TYPE_BIO_BASED)
|
|
ti->per_io_data_size = multipath_per_bio_data_size();
|
|
else
|
|
ti->per_io_data_size = sizeof(struct dm_mpath_io);
|
|
|
|
return 0;
|
|
|
|
bad:
|
|
free_multipath(m);
|
|
return r;
|
|
}
|
|
|
|
static void multipath_wait_for_pg_init_completion(struct multipath *m)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
|
|
while (1) {
|
|
prepare_to_wait(&m->pg_init_wait, &wait, TASK_UNINTERRUPTIBLE);
|
|
|
|
if (!atomic_read(&m->pg_init_in_progress))
|
|
break;
|
|
|
|
io_schedule();
|
|
}
|
|
finish_wait(&m->pg_init_wait, &wait);
|
|
}
|
|
|
|
static void flush_multipath_work(struct multipath *m)
|
|
{
|
|
set_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
|
|
smp_mb__after_atomic();
|
|
|
|
flush_workqueue(kmpath_handlerd);
|
|
multipath_wait_for_pg_init_completion(m);
|
|
flush_workqueue(kmultipathd);
|
|
flush_work(&m->trigger_event);
|
|
|
|
clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
|
|
smp_mb__after_atomic();
|
|
}
|
|
|
|
static void multipath_dtr(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
|
|
flush_multipath_work(m);
|
|
free_multipath(m);
|
|
}
|
|
|
|
/*
|
|
* Take a path out of use.
|
|
*/
|
|
static int fail_path(struct pgpath *pgpath)
|
|
{
|
|
unsigned long flags;
|
|
struct multipath *m = pgpath->pg->m;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (!pgpath->is_active)
|
|
goto out;
|
|
|
|
DMWARN("Failing path %s.", pgpath->path.dev->name);
|
|
|
|
pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
|
|
pgpath->is_active = false;
|
|
pgpath->fail_count++;
|
|
|
|
atomic_dec(&m->nr_valid_paths);
|
|
|
|
if (pgpath == m->current_pgpath)
|
|
m->current_pgpath = NULL;
|
|
|
|
dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
|
|
pgpath->path.dev->name, atomic_read(&m->nr_valid_paths));
|
|
|
|
schedule_work(&m->trigger_event);
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Reinstate a previously-failed path
|
|
*/
|
|
static int reinstate_path(struct pgpath *pgpath)
|
|
{
|
|
int r = 0, run_queue = 0;
|
|
unsigned long flags;
|
|
struct multipath *m = pgpath->pg->m;
|
|
unsigned nr_valid_paths;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (pgpath->is_active)
|
|
goto out;
|
|
|
|
DMWARN("Reinstating path %s.", pgpath->path.dev->name);
|
|
|
|
r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
|
|
if (r)
|
|
goto out;
|
|
|
|
pgpath->is_active = true;
|
|
|
|
nr_valid_paths = atomic_inc_return(&m->nr_valid_paths);
|
|
if (nr_valid_paths == 1) {
|
|
m->current_pgpath = NULL;
|
|
run_queue = 1;
|
|
} else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) {
|
|
if (queue_work(kmpath_handlerd, &pgpath->activate_path.work))
|
|
atomic_inc(&m->pg_init_in_progress);
|
|
}
|
|
|
|
dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
|
|
pgpath->path.dev->name, nr_valid_paths);
|
|
|
|
schedule_work(&m->trigger_event);
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
if (run_queue) {
|
|
dm_table_run_md_queue_async(m->ti->table);
|
|
process_queued_io_list(m);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Fail or reinstate all paths that match the provided struct dm_dev.
|
|
*/
|
|
static int action_dev(struct multipath *m, struct dm_dev *dev,
|
|
action_fn action)
|
|
{
|
|
int r = -EINVAL;
|
|
struct pgpath *pgpath;
|
|
struct priority_group *pg;
|
|
|
|
list_for_each_entry(pg, &m->priority_groups, list) {
|
|
list_for_each_entry(pgpath, &pg->pgpaths, list) {
|
|
if (pgpath->path.dev == dev)
|
|
r = action(pgpath);
|
|
}
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Temporarily try to avoid having to use the specified PG
|
|
*/
|
|
static void bypass_pg(struct multipath *m, struct priority_group *pg,
|
|
bool bypassed)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
pg->bypassed = bypassed;
|
|
m->current_pgpath = NULL;
|
|
m->current_pg = NULL;
|
|
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
schedule_work(&m->trigger_event);
|
|
}
|
|
|
|
/*
|
|
* Switch to using the specified PG from the next I/O that gets mapped
|
|
*/
|
|
static int switch_pg_num(struct multipath *m, const char *pgstr)
|
|
{
|
|
struct priority_group *pg;
|
|
unsigned pgnum;
|
|
unsigned long flags;
|
|
char dummy;
|
|
|
|
if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
|
|
!m->nr_priority_groups || (pgnum > m->nr_priority_groups)) {
|
|
DMWARN("invalid PG number supplied to switch_pg_num");
|
|
return -EINVAL;
|
|
}
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
list_for_each_entry(pg, &m->priority_groups, list) {
|
|
pg->bypassed = false;
|
|
if (--pgnum)
|
|
continue;
|
|
|
|
m->current_pgpath = NULL;
|
|
m->current_pg = NULL;
|
|
m->next_pg = pg;
|
|
}
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
schedule_work(&m->trigger_event);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Set/clear bypassed status of a PG.
|
|
* PGs are numbered upwards from 1 in the order they were declared.
|
|
*/
|
|
static int bypass_pg_num(struct multipath *m, const char *pgstr, bool bypassed)
|
|
{
|
|
struct priority_group *pg;
|
|
unsigned pgnum;
|
|
char dummy;
|
|
|
|
if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
|
|
!m->nr_priority_groups || (pgnum > m->nr_priority_groups)) {
|
|
DMWARN("invalid PG number supplied to bypass_pg");
|
|
return -EINVAL;
|
|
}
|
|
|
|
list_for_each_entry(pg, &m->priority_groups, list) {
|
|
if (!--pgnum)
|
|
break;
|
|
}
|
|
|
|
bypass_pg(m, pg, bypassed);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Should we retry pg_init immediately?
|
|
*/
|
|
static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
|
|
{
|
|
unsigned long flags;
|
|
bool limit_reached = false;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (atomic_read(&m->pg_init_count) <= m->pg_init_retries &&
|
|
!test_bit(MPATHF_PG_INIT_DISABLED, &m->flags))
|
|
set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags);
|
|
else
|
|
limit_reached = true;
|
|
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
return limit_reached;
|
|
}
|
|
|
|
static void pg_init_done(void *data, int errors)
|
|
{
|
|
struct pgpath *pgpath = data;
|
|
struct priority_group *pg = pgpath->pg;
|
|
struct multipath *m = pg->m;
|
|
unsigned long flags;
|
|
bool delay_retry = false;
|
|
|
|
/* device or driver problems */
|
|
switch (errors) {
|
|
case SCSI_DH_OK:
|
|
break;
|
|
case SCSI_DH_NOSYS:
|
|
if (!m->hw_handler_name) {
|
|
errors = 0;
|
|
break;
|
|
}
|
|
DMERR("Could not failover the device: Handler scsi_dh_%s "
|
|
"Error %d.", m->hw_handler_name, errors);
|
|
/*
|
|
* Fail path for now, so we do not ping pong
|
|
*/
|
|
fail_path(pgpath);
|
|
break;
|
|
case SCSI_DH_DEV_TEMP_BUSY:
|
|
/*
|
|
* Probably doing something like FW upgrade on the
|
|
* controller so try the other pg.
|
|
*/
|
|
bypass_pg(m, pg, true);
|
|
break;
|
|
case SCSI_DH_RETRY:
|
|
/* Wait before retrying. */
|
|
delay_retry = 1;
|
|
case SCSI_DH_IMM_RETRY:
|
|
case SCSI_DH_RES_TEMP_UNAVAIL:
|
|
if (pg_init_limit_reached(m, pgpath))
|
|
fail_path(pgpath);
|
|
errors = 0;
|
|
break;
|
|
case SCSI_DH_DEV_OFFLINED:
|
|
default:
|
|
/*
|
|
* We probably do not want to fail the path for a device
|
|
* error, but this is what the old dm did. In future
|
|
* patches we can do more advanced handling.
|
|
*/
|
|
fail_path(pgpath);
|
|
}
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
if (errors) {
|
|
if (pgpath == m->current_pgpath) {
|
|
DMERR("Could not failover device. Error %d.", errors);
|
|
m->current_pgpath = NULL;
|
|
m->current_pg = NULL;
|
|
}
|
|
} else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
|
|
pg->bypassed = false;
|
|
|
|
if (atomic_dec_return(&m->pg_init_in_progress) > 0)
|
|
/* Activations of other paths are still on going */
|
|
goto out;
|
|
|
|
if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) {
|
|
if (delay_retry)
|
|
set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
|
|
else
|
|
clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);
|
|
|
|
if (__pg_init_all_paths(m))
|
|
goto out;
|
|
}
|
|
clear_bit(MPATHF_QUEUE_IO, &m->flags);
|
|
|
|
process_queued_io_list(m);
|
|
|
|
/*
|
|
* Wake up any thread waiting to suspend.
|
|
*/
|
|
wake_up(&m->pg_init_wait);
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
}
|
|
|
|
static void activate_path(struct work_struct *work)
|
|
{
|
|
struct pgpath *pgpath =
|
|
container_of(work, struct pgpath, activate_path.work);
|
|
struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
|
|
|
|
if (pgpath->is_active && !blk_queue_dying(q))
|
|
scsi_dh_activate(q, pg_init_done, pgpath);
|
|
else
|
|
pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
|
|
}
|
|
|
|
static int noretry_error(int error)
|
|
{
|
|
switch (error) {
|
|
case -EBADE:
|
|
/*
|
|
* EBADE signals an reservation conflict.
|
|
* We shouldn't fail the path here as we can communicate with
|
|
* the target. We should failover to the next path, but in
|
|
* doing so we might be causing a ping-pong between paths.
|
|
* So just return the reservation conflict error.
|
|
*/
|
|
case -EOPNOTSUPP:
|
|
case -EREMOTEIO:
|
|
case -EILSEQ:
|
|
case -ENODATA:
|
|
case -ENOSPC:
|
|
return 1;
|
|
}
|
|
|
|
/* Anything else could be a path failure, so should be retried */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* end_io handling
|
|
*/
|
|
static int do_end_io(struct multipath *m, struct request *clone,
|
|
int error, struct dm_mpath_io *mpio)
|
|
{
|
|
/*
|
|
* We don't queue any clone request inside the multipath target
|
|
* during end I/O handling, since those clone requests don't have
|
|
* bio clones. If we queue them inside the multipath target,
|
|
* we need to make bio clones, that requires memory allocation.
|
|
* (See drivers/md/dm-rq.c:end_clone_bio() about why the clone requests
|
|
* don't have bio clones.)
|
|
* Instead of queueing the clone request here, we queue the original
|
|
* request into dm core, which will remake a clone request and
|
|
* clone bios for it and resubmit it later.
|
|
*/
|
|
int r = DM_ENDIO_REQUEUE;
|
|
|
|
if (!error && !clone->errors)
|
|
return 0; /* I/O complete */
|
|
|
|
if (noretry_error(error))
|
|
return error;
|
|
|
|
if (mpio->pgpath)
|
|
fail_path(mpio->pgpath);
|
|
|
|
if (!atomic_read(&m->nr_valid_paths)) {
|
|
if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
|
|
if (!must_push_back_rq(m))
|
|
r = -EIO;
|
|
}
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int multipath_end_io(struct dm_target *ti, struct request *clone,
|
|
int error, union map_info *map_context)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
struct dm_mpath_io *mpio = get_mpio(map_context);
|
|
struct pgpath *pgpath;
|
|
struct path_selector *ps;
|
|
int r;
|
|
|
|
BUG_ON(!mpio);
|
|
|
|
r = do_end_io(m, clone, error, mpio);
|
|
pgpath = mpio->pgpath;
|
|
if (pgpath) {
|
|
ps = &pgpath->pg->ps;
|
|
if (ps->type->end_io)
|
|
ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static int do_end_io_bio(struct multipath *m, struct bio *clone,
|
|
int error, struct dm_mpath_io *mpio)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!error)
|
|
return 0; /* I/O complete */
|
|
|
|
if (noretry_error(error))
|
|
return error;
|
|
|
|
if (mpio->pgpath)
|
|
fail_path(mpio->pgpath);
|
|
|
|
if (!atomic_read(&m->nr_valid_paths)) {
|
|
if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
|
|
if (!must_push_back_bio(m))
|
|
return -EIO;
|
|
return DM_ENDIO_REQUEUE;
|
|
}
|
|
}
|
|
|
|
/* Queue for the daemon to resubmit */
|
|
dm_bio_restore(get_bio_details_from_bio(clone), clone);
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
bio_list_add(&m->queued_bios, clone);
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
|
|
queue_work(kmultipathd, &m->process_queued_bios);
|
|
|
|
return DM_ENDIO_INCOMPLETE;
|
|
}
|
|
|
|
static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, int error)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
|
|
struct pgpath *pgpath;
|
|
struct path_selector *ps;
|
|
int r;
|
|
|
|
BUG_ON(!mpio);
|
|
|
|
r = do_end_io_bio(m, clone, error, mpio);
|
|
pgpath = mpio->pgpath;
|
|
if (pgpath) {
|
|
ps = &pgpath->pg->ps;
|
|
if (ps->type->end_io)
|
|
ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Suspend can't complete until all the I/O is processed so if
|
|
* the last path fails we must error any remaining I/O.
|
|
* Note that if the freeze_bdev fails while suspending, the
|
|
* queue_if_no_path state is lost - userspace should reset it.
|
|
*/
|
|
static void multipath_presuspend(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
|
|
queue_if_no_path(m, false, true);
|
|
}
|
|
|
|
static void multipath_postsuspend(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
|
|
mutex_lock(&m->work_mutex);
|
|
flush_multipath_work(m);
|
|
mutex_unlock(&m->work_mutex);
|
|
}
|
|
|
|
/*
|
|
* Restore the queue_if_no_path setting.
|
|
*/
|
|
static void multipath_resume(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags))
|
|
set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
|
|
else
|
|
clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
}
|
|
|
|
/*
|
|
* Info output has the following format:
|
|
* num_multipath_feature_args [multipath_feature_args]*
|
|
* num_handler_status_args [handler_status_args]*
|
|
* num_groups init_group_number
|
|
* [A|D|E num_ps_status_args [ps_status_args]*
|
|
* num_paths num_selector_args
|
|
* [path_dev A|F fail_count [selector_args]* ]+ ]+
|
|
*
|
|
* Table output has the following format (identical to the constructor string):
|
|
* num_feature_args [features_args]*
|
|
* num_handler_args hw_handler [hw_handler_args]*
|
|
* num_groups init_group_number
|
|
* [priority selector-name num_ps_args [ps_args]*
|
|
* num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
|
|
*/
|
|
static void multipath_status(struct dm_target *ti, status_type_t type,
|
|
unsigned status_flags, char *result, unsigned maxlen)
|
|
{
|
|
int sz = 0;
|
|
unsigned long flags;
|
|
struct multipath *m = ti->private;
|
|
struct priority_group *pg;
|
|
struct pgpath *p;
|
|
unsigned pg_num;
|
|
char state;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
/* Features */
|
|
if (type == STATUSTYPE_INFO)
|
|
DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags),
|
|
atomic_read(&m->pg_init_count));
|
|
else {
|
|
DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) +
|
|
(m->pg_init_retries > 0) * 2 +
|
|
(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 +
|
|
test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) +
|
|
(m->queue_mode != DM_TYPE_REQUEST_BASED) * 2);
|
|
|
|
if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
|
|
DMEMIT("queue_if_no_path ");
|
|
if (m->pg_init_retries)
|
|
DMEMIT("pg_init_retries %u ", m->pg_init_retries);
|
|
if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
|
|
DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
|
|
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags))
|
|
DMEMIT("retain_attached_hw_handler ");
|
|
if (m->queue_mode != DM_TYPE_REQUEST_BASED) {
|
|
switch(m->queue_mode) {
|
|
case DM_TYPE_BIO_BASED:
|
|
DMEMIT("queue_mode bio ");
|
|
break;
|
|
case DM_TYPE_MQ_REQUEST_BASED:
|
|
DMEMIT("queue_mode mq ");
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!m->hw_handler_name || type == STATUSTYPE_INFO)
|
|
DMEMIT("0 ");
|
|
else
|
|
DMEMIT("1 %s ", m->hw_handler_name);
|
|
|
|
DMEMIT("%u ", m->nr_priority_groups);
|
|
|
|
if (m->next_pg)
|
|
pg_num = m->next_pg->pg_num;
|
|
else if (m->current_pg)
|
|
pg_num = m->current_pg->pg_num;
|
|
else
|
|
pg_num = (m->nr_priority_groups ? 1 : 0);
|
|
|
|
DMEMIT("%u ", pg_num);
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
list_for_each_entry(pg, &m->priority_groups, list) {
|
|
if (pg->bypassed)
|
|
state = 'D'; /* Disabled */
|
|
else if (pg == m->current_pg)
|
|
state = 'A'; /* Currently Active */
|
|
else
|
|
state = 'E'; /* Enabled */
|
|
|
|
DMEMIT("%c ", state);
|
|
|
|
if (pg->ps.type->status)
|
|
sz += pg->ps.type->status(&pg->ps, NULL, type,
|
|
result + sz,
|
|
maxlen - sz);
|
|
else
|
|
DMEMIT("0 ");
|
|
|
|
DMEMIT("%u %u ", pg->nr_pgpaths,
|
|
pg->ps.type->info_args);
|
|
|
|
list_for_each_entry(p, &pg->pgpaths, list) {
|
|
DMEMIT("%s %s %u ", p->path.dev->name,
|
|
p->is_active ? "A" : "F",
|
|
p->fail_count);
|
|
if (pg->ps.type->status)
|
|
sz += pg->ps.type->status(&pg->ps,
|
|
&p->path, type, result + sz,
|
|
maxlen - sz);
|
|
}
|
|
}
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
list_for_each_entry(pg, &m->priority_groups, list) {
|
|
DMEMIT("%s ", pg->ps.type->name);
|
|
|
|
if (pg->ps.type->status)
|
|
sz += pg->ps.type->status(&pg->ps, NULL, type,
|
|
result + sz,
|
|
maxlen - sz);
|
|
else
|
|
DMEMIT("0 ");
|
|
|
|
DMEMIT("%u %u ", pg->nr_pgpaths,
|
|
pg->ps.type->table_args);
|
|
|
|
list_for_each_entry(p, &pg->pgpaths, list) {
|
|
DMEMIT("%s ", p->path.dev->name);
|
|
if (pg->ps.type->status)
|
|
sz += pg->ps.type->status(&pg->ps,
|
|
&p->path, type, result + sz,
|
|
maxlen - sz);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
}
|
|
|
|
static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
|
|
{
|
|
int r = -EINVAL;
|
|
struct dm_dev *dev;
|
|
struct multipath *m = ti->private;
|
|
action_fn action;
|
|
|
|
mutex_lock(&m->work_mutex);
|
|
|
|
if (dm_suspended(ti)) {
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
if (argc == 1) {
|
|
if (!strcasecmp(argv[0], "queue_if_no_path")) {
|
|
r = queue_if_no_path(m, true, false);
|
|
goto out;
|
|
} else if (!strcasecmp(argv[0], "fail_if_no_path")) {
|
|
r = queue_if_no_path(m, false, false);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
if (argc != 2) {
|
|
DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc);
|
|
goto out;
|
|
}
|
|
|
|
if (!strcasecmp(argv[0], "disable_group")) {
|
|
r = bypass_pg_num(m, argv[1], true);
|
|
goto out;
|
|
} else if (!strcasecmp(argv[0], "enable_group")) {
|
|
r = bypass_pg_num(m, argv[1], false);
|
|
goto out;
|
|
} else if (!strcasecmp(argv[0], "switch_group")) {
|
|
r = switch_pg_num(m, argv[1]);
|
|
goto out;
|
|
} else if (!strcasecmp(argv[0], "reinstate_path"))
|
|
action = reinstate_path;
|
|
else if (!strcasecmp(argv[0], "fail_path"))
|
|
action = fail_path;
|
|
else {
|
|
DMWARN("Unrecognised multipath message received: %s", argv[0]);
|
|
goto out;
|
|
}
|
|
|
|
r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev);
|
|
if (r) {
|
|
DMWARN("message: error getting device %s",
|
|
argv[1]);
|
|
goto out;
|
|
}
|
|
|
|
r = action_dev(m, dev, action);
|
|
|
|
dm_put_device(ti, dev);
|
|
|
|
out:
|
|
mutex_unlock(&m->work_mutex);
|
|
return r;
|
|
}
|
|
|
|
static int multipath_prepare_ioctl(struct dm_target *ti,
|
|
struct block_device **bdev, fmode_t *mode)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
struct pgpath *current_pgpath;
|
|
int r;
|
|
|
|
current_pgpath = lockless_dereference(m->current_pgpath);
|
|
if (!current_pgpath)
|
|
current_pgpath = choose_pgpath(m, 0);
|
|
|
|
if (current_pgpath) {
|
|
if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) {
|
|
*bdev = current_pgpath->path.dev->bdev;
|
|
*mode = current_pgpath->path.dev->mode;
|
|
r = 0;
|
|
} else {
|
|
/* pg_init has not started or completed */
|
|
r = -ENOTCONN;
|
|
}
|
|
} else {
|
|
/* No path is available */
|
|
if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
|
|
r = -ENOTCONN;
|
|
else
|
|
r = -EIO;
|
|
}
|
|
|
|
if (r == -ENOTCONN) {
|
|
if (!lockless_dereference(m->current_pg)) {
|
|
/* Path status changed, redo selection */
|
|
(void) choose_pgpath(m, 0);
|
|
}
|
|
if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
|
|
pg_init_all_paths(m);
|
|
dm_table_run_md_queue_async(m->ti->table);
|
|
process_queued_io_list(m);
|
|
}
|
|
|
|
/*
|
|
* Only pass ioctls through if the device sizes match exactly.
|
|
*/
|
|
if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
|
|
return 1;
|
|
return r;
|
|
}
|
|
|
|
static int multipath_iterate_devices(struct dm_target *ti,
|
|
iterate_devices_callout_fn fn, void *data)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
struct priority_group *pg;
|
|
struct pgpath *p;
|
|
int ret = 0;
|
|
|
|
list_for_each_entry(pg, &m->priority_groups, list) {
|
|
list_for_each_entry(p, &pg->pgpaths, list) {
|
|
ret = fn(ti, p->path.dev, ti->begin, ti->len, data);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int pgpath_busy(struct pgpath *pgpath)
|
|
{
|
|
struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
|
|
|
|
return blk_lld_busy(q);
|
|
}
|
|
|
|
/*
|
|
* We return "busy", only when we can map I/Os but underlying devices
|
|
* are busy (so even if we map I/Os now, the I/Os will wait on
|
|
* the underlying queue).
|
|
* In other words, if we want to kill I/Os or queue them inside us
|
|
* due to map unavailability, we don't return "busy". Otherwise,
|
|
* dm core won't give us the I/Os and we can't do what we want.
|
|
*/
|
|
static int multipath_busy(struct dm_target *ti)
|
|
{
|
|
bool busy = false, has_active = false;
|
|
struct multipath *m = ti->private;
|
|
struct priority_group *pg, *next_pg;
|
|
struct pgpath *pgpath;
|
|
|
|
/* pg_init in progress */
|
|
if (atomic_read(&m->pg_init_in_progress))
|
|
return true;
|
|
|
|
/* no paths available, for blk-mq: rely on IO mapping to delay requeue */
|
|
if (!atomic_read(&m->nr_valid_paths) && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
|
|
return (m->queue_mode != DM_TYPE_MQ_REQUEST_BASED);
|
|
|
|
/* Guess which priority_group will be used at next mapping time */
|
|
pg = lockless_dereference(m->current_pg);
|
|
next_pg = lockless_dereference(m->next_pg);
|
|
if (unlikely(!lockless_dereference(m->current_pgpath) && next_pg))
|
|
pg = next_pg;
|
|
|
|
if (!pg) {
|
|
/*
|
|
* We don't know which pg will be used at next mapping time.
|
|
* We don't call choose_pgpath() here to avoid to trigger
|
|
* pg_init just by busy checking.
|
|
* So we don't know whether underlying devices we will be using
|
|
* at next mapping time are busy or not. Just try mapping.
|
|
*/
|
|
return busy;
|
|
}
|
|
|
|
/*
|
|
* If there is one non-busy active path at least, the path selector
|
|
* will be able to select it. So we consider such a pg as not busy.
|
|
*/
|
|
busy = true;
|
|
list_for_each_entry(pgpath, &pg->pgpaths, list) {
|
|
if (pgpath->is_active) {
|
|
has_active = true;
|
|
if (!pgpath_busy(pgpath)) {
|
|
busy = false;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!has_active) {
|
|
/*
|
|
* No active path in this pg, so this pg won't be used and
|
|
* the current_pg will be changed at next mapping time.
|
|
* We need to try mapping to determine it.
|
|
*/
|
|
busy = false;
|
|
}
|
|
|
|
return busy;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Module setup
|
|
*---------------------------------------------------------------*/
|
|
static struct target_type multipath_target = {
|
|
.name = "multipath",
|
|
.version = {1, 12, 0},
|
|
.features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
|
|
.module = THIS_MODULE,
|
|
.ctr = multipath_ctr,
|
|
.dtr = multipath_dtr,
|
|
.clone_and_map_rq = multipath_clone_and_map,
|
|
.release_clone_rq = multipath_release_clone,
|
|
.rq_end_io = multipath_end_io,
|
|
.map = multipath_map_bio,
|
|
.end_io = multipath_end_io_bio,
|
|
.presuspend = multipath_presuspend,
|
|
.postsuspend = multipath_postsuspend,
|
|
.resume = multipath_resume,
|
|
.status = multipath_status,
|
|
.message = multipath_message,
|
|
.prepare_ioctl = multipath_prepare_ioctl,
|
|
.iterate_devices = multipath_iterate_devices,
|
|
.busy = multipath_busy,
|
|
};
|
|
|
|
static int __init dm_multipath_init(void)
|
|
{
|
|
int r;
|
|
|
|
r = dm_register_target(&multipath_target);
|
|
if (r < 0) {
|
|
DMERR("request-based register failed %d", r);
|
|
r = -EINVAL;
|
|
goto bad_register_target;
|
|
}
|
|
|
|
kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0);
|
|
if (!kmultipathd) {
|
|
DMERR("failed to create workqueue kmpathd");
|
|
r = -ENOMEM;
|
|
goto bad_alloc_kmultipathd;
|
|
}
|
|
|
|
/*
|
|
* A separate workqueue is used to handle the device handlers
|
|
* to avoid overloading existing workqueue. Overloading the
|
|
* old workqueue would also create a bottleneck in the
|
|
* path of the storage hardware device activation.
|
|
*/
|
|
kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd",
|
|
WQ_MEM_RECLAIM);
|
|
if (!kmpath_handlerd) {
|
|
DMERR("failed to create workqueue kmpath_handlerd");
|
|
r = -ENOMEM;
|
|
goto bad_alloc_kmpath_handlerd;
|
|
}
|
|
|
|
return 0;
|
|
|
|
bad_alloc_kmpath_handlerd:
|
|
destroy_workqueue(kmultipathd);
|
|
bad_alloc_kmultipathd:
|
|
dm_unregister_target(&multipath_target);
|
|
bad_register_target:
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_multipath_exit(void)
|
|
{
|
|
destroy_workqueue(kmpath_handlerd);
|
|
destroy_workqueue(kmultipathd);
|
|
|
|
dm_unregister_target(&multipath_target);
|
|
}
|
|
|
|
module_init(dm_multipath_init);
|
|
module_exit(dm_multipath_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " multipath target");
|
|
MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|