![Moger, Babu](/assets/img/avatar_default.png)
This patch removes some unnecessary argument casting. There is no functional change with this patch. Passes 'struct pgpath' through to pg_init_done() instead of the enclosed 'struct dm_path'. Tested the changes with LSI storage.. CC: Chandra Seetharaman <chandra.seetharaman@us.ibm.com> Signed-off-by: Babu Moger <babu.moger@lsi.com> Acked-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1690 lines
38 KiB
C
1690 lines
38 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-path-selector.h"
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#include "dm-uevent.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 <scsi/scsi_dh.h>
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#include <asm/atomic.h>
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#define DM_MSG_PREFIX "multipath"
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#define MESG_STR(x) x, sizeof(x)
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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 is_active; /* Path status */
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unsigned fail_count; /* Cumulative failure count */
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struct dm_path path;
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struct work_struct deactivate_path;
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struct work_struct activate_path;
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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 bypassed; /* Temporarily bypass this PG? */
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unsigned nr_pgpaths; /* Number of paths in PG */
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struct list_head pgpaths;
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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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spinlock_t lock;
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const char *hw_handler_name;
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char *hw_handler_params;
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unsigned nr_priority_groups;
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struct list_head priority_groups;
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unsigned pg_init_required; /* pg_init needs calling? */
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unsigned pg_init_in_progress; /* Only one pg_init allowed at once */
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unsigned nr_valid_paths; /* Total number of usable paths */
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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 repeat_count; /* I/Os left before calling PS again */
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unsigned queue_io; /* Must we queue all I/O? */
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unsigned queue_if_no_path; /* Queue I/O if last path fails? */
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unsigned saved_queue_if_no_path;/* Saved state during suspension */
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unsigned pg_init_retries; /* Number of times to retry pg_init */
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unsigned pg_init_count; /* Number of times pg_init called */
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struct work_struct process_queued_ios;
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struct list_head queued_ios;
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unsigned queue_size;
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struct work_struct trigger_event;
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/*
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* We must use a mempool of dm_mpath_io structs so that we
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* can resubmit bios on error.
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*/
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mempool_t *mpio_pool;
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struct mutex work_mutex;
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unsigned suspended; /* Don't create new I/O internally when set. */
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};
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/*
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* Context information attached to each bio 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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#define MIN_IOS 256 /* Mempool size */
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static struct kmem_cache *_mpio_cache;
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static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
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static void process_queued_ios(struct work_struct *work);
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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 deactivate_path(struct work_struct *work);
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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 = 1;
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INIT_WORK(&pgpath->deactivate_path, deactivate_path);
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INIT_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 void deactivate_path(struct work_struct *work)
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{
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struct pgpath *pgpath =
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container_of(work, struct pgpath, deactivate_path);
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blk_abort_queue(pgpath->path.dev->bdev->bd_disk->queue);
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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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struct multipath *m = ti->private;
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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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if (m->hw_handler_name)
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scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev));
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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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INIT_LIST_HEAD(&m->queued_ios);
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spin_lock_init(&m->lock);
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m->queue_io = 1;
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INIT_WORK(&m->process_queued_ios, process_queued_ios);
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INIT_WORK(&m->trigger_event, trigger_event);
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mutex_init(&m->work_mutex);
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m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
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if (!m->mpio_pool) {
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kfree(m);
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return NULL;
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}
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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 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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mempool_destroy(m->mpio_pool);
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kfree(m);
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}
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/*-----------------------------------------------
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* Path selection
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*-----------------------------------------------*/
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static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
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{
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m->current_pg = pgpath->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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m->pg_init_required = 1;
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m->queue_io = 1;
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} else {
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m->pg_init_required = 0;
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m->queue_io = 0;
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}
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m->pg_init_count = 0;
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}
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static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg,
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size_t nr_bytes)
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{
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struct dm_path *path;
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path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes);
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if (!path)
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return -ENXIO;
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m->current_pgpath = path_to_pgpath(path);
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if (m->current_pg != pg)
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__switch_pg(m, m->current_pgpath);
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return 0;
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}
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static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
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{
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struct priority_group *pg;
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unsigned bypassed = 1;
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if (!m->nr_valid_paths)
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goto failed;
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/* Were we instructed to switch PG? */
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if (m->next_pg) {
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pg = m->next_pg;
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m->next_pg = NULL;
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if (!__choose_path_in_pg(m, pg, nr_bytes))
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return;
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}
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/* Don't change PG until it has no remaining paths */
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if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes))
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return;
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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.
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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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if (!__choose_path_in_pg(m, pg, nr_bytes))
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return;
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}
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} while (bypassed--);
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failed:
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m->current_pgpath = NULL;
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m->current_pg = 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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* m->lock must be held on entry.
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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 int __must_push_back(struct multipath *m)
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{
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return (m->queue_if_no_path != m->saved_queue_if_no_path &&
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dm_noflush_suspending(m->ti));
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}
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static int map_io(struct multipath *m, struct request *clone,
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struct dm_mpath_io *mpio, unsigned was_queued)
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{
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int r = DM_MAPIO_REMAPPED;
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size_t nr_bytes = blk_rq_bytes(clone);
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unsigned long flags;
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struct pgpath *pgpath;
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struct block_device *bdev;
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spin_lock_irqsave(&m->lock, flags);
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/* Do we need to select a new pgpath? */
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if (!m->current_pgpath ||
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(!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
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__choose_pgpath(m, nr_bytes);
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pgpath = m->current_pgpath;
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if (was_queued)
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m->queue_size--;
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if ((pgpath && m->queue_io) ||
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(!pgpath && m->queue_if_no_path)) {
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/* Queue for the daemon to resubmit */
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list_add_tail(&clone->queuelist, &m->queued_ios);
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m->queue_size++;
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if ((m->pg_init_required && !m->pg_init_in_progress) ||
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!m->queue_io)
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queue_work(kmultipathd, &m->process_queued_ios);
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pgpath = NULL;
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r = DM_MAPIO_SUBMITTED;
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} else if (pgpath) {
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bdev = pgpath->path.dev->bdev;
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clone->q = bdev_get_queue(bdev);
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clone->rq_disk = bdev->bd_disk;
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} else if (__must_push_back(m))
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r = DM_MAPIO_REQUEUE;
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else
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r = -EIO; /* Failed */
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mpio->pgpath = pgpath;
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mpio->nr_bytes = nr_bytes;
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if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io)
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pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path,
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nr_bytes);
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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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* If we run out of usable paths, should we queue I/O or error it?
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*/
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static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path,
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unsigned save_old_value)
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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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if (save_old_value)
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m->saved_queue_if_no_path = m->queue_if_no_path;
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else
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m->saved_queue_if_no_path = queue_if_no_path;
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m->queue_if_no_path = queue_if_no_path;
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if (!m->queue_if_no_path && m->queue_size)
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queue_work(kmultipathd, &m->process_queued_ios);
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spin_unlock_irqrestore(&m->lock, flags);
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return 0;
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}
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/*-----------------------------------------------------------------
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* The multipath daemon is responsible for resubmitting queued ios.
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*---------------------------------------------------------------*/
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static void dispatch_queued_ios(struct multipath *m)
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{
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int r;
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unsigned long flags;
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struct dm_mpath_io *mpio;
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union map_info *info;
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struct request *clone, *n;
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LIST_HEAD(cl);
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spin_lock_irqsave(&m->lock, flags);
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list_splice_init(&m->queued_ios, &cl);
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spin_unlock_irqrestore(&m->lock, flags);
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list_for_each_entry_safe(clone, n, &cl, queuelist) {
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list_del_init(&clone->queuelist);
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info = dm_get_rq_mapinfo(clone);
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mpio = info->ptr;
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r = map_io(m, clone, mpio, 1);
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if (r < 0) {
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mempool_free(mpio, m->mpio_pool);
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dm_kill_unmapped_request(clone, r);
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} else if (r == DM_MAPIO_REMAPPED)
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dm_dispatch_request(clone);
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else if (r == DM_MAPIO_REQUEUE) {
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mempool_free(mpio, m->mpio_pool);
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dm_requeue_unmapped_request(clone);
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}
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}
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}
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static void process_queued_ios(struct work_struct *work)
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{
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struct multipath *m =
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container_of(work, struct multipath, process_queued_ios);
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struct pgpath *pgpath = NULL, *tmp;
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unsigned must_queue = 1;
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unsigned long flags;
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spin_lock_irqsave(&m->lock, flags);
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if (!m->queue_size)
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goto out;
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if (!m->current_pgpath)
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__choose_pgpath(m, 0);
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pgpath = m->current_pgpath;
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if ((pgpath && !m->queue_io) ||
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(!pgpath && !m->queue_if_no_path))
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must_queue = 0;
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if (m->pg_init_required && !m->pg_init_in_progress && pgpath) {
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m->pg_init_count++;
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m->pg_init_required = 0;
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list_for_each_entry(tmp, &pgpath->pg->pgpaths, list) {
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if (queue_work(kmpath_handlerd, &tmp->activate_path))
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m->pg_init_in_progress++;
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}
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}
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out:
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spin_unlock_irqrestore(&m->lock, flags);
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if (!must_queue)
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dispatch_queued_ios(m);
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}
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/*
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* An event is triggered whenever a path is taken out of use.
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* Includes path failure and PG bypass.
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*/
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static void trigger_event(struct work_struct *work)
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{
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struct multipath *m =
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container_of(work, struct multipath, trigger_event);
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dm_table_event(m->ti->table);
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}
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/*-----------------------------------------------------------------
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* Constructor/argument parsing:
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* <#multipath feature args> [<arg>]*
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* <#hw_handler args> [hw_handler [<arg>]*]
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* <#priority groups>
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* <initial priority group>
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* [<selector> <#selector args> [<arg>]*
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* <#paths> <#per-path selector args>
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* [<path> [<arg>]* ]+ ]+
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*---------------------------------------------------------------*/
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struct param {
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unsigned min;
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unsigned max;
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char *error;
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};
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static int read_param(struct param *param, char *str, unsigned *v, char **error)
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{
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if (!str ||
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(sscanf(str, "%u", v) != 1) ||
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(*v < param->min) ||
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(*v > param->max)) {
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*error = param->error;
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return -EINVAL;
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}
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return 0;
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}
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struct arg_set {
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unsigned argc;
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char **argv;
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};
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static char *shift(struct arg_set *as)
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{
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char *r;
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if (as->argc) {
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as->argc--;
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r = *as->argv;
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as->argv++;
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return r;
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}
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return NULL;
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}
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static void consume(struct arg_set *as, unsigned n)
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{
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BUG_ON (as->argc < n);
|
|
as->argc -= n;
|
|
as->argv += n;
|
|
}
|
|
|
|
static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
|
|
struct dm_target *ti)
|
|
{
|
|
int r;
|
|
struct path_selector_type *pst;
|
|
unsigned ps_argc;
|
|
|
|
static struct param _params[] = {
|
|
{0, 1024, "invalid number of path selector args"},
|
|
};
|
|
|
|
pst = dm_get_path_selector(shift(as));
|
|
if (!pst) {
|
|
ti->error = "unknown path selector type";
|
|
return -EINVAL;
|
|
}
|
|
|
|
r = read_param(_params, shift(as), &ps_argc, &ti->error);
|
|
if (r) {
|
|
dm_put_path_selector(pst);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (ps_argc > as->argc) {
|
|
dm_put_path_selector(pst);
|
|
ti->error = "not enough arguments for path selector";
|
|
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;
|
|
consume(as, ps_argc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
|
|
struct dm_target *ti)
|
|
{
|
|
int r;
|
|
struct pgpath *p;
|
|
struct multipath *m = ti->private;
|
|
|
|
/* 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, shift(as), ti->begin, ti->len,
|
|
dm_table_get_mode(ti->table), &p->path.dev);
|
|
if (r) {
|
|
ti->error = "error getting device";
|
|
goto bad;
|
|
}
|
|
|
|
if (m->hw_handler_name) {
|
|
struct request_queue *q = bdev_get_queue(p->path.dev->bdev);
|
|
|
|
r = scsi_dh_attach(q, m->hw_handler_name);
|
|
if (r == -EBUSY) {
|
|
/*
|
|
* Already attached to different hw_handler,
|
|
* try to reattach with correct one.
|
|
*/
|
|
scsi_dh_detach(q);
|
|
r = scsi_dh_attach(q, m->hw_handler_name);
|
|
}
|
|
|
|
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";
|
|
scsi_dh_detach(q);
|
|
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 arg_set *as,
|
|
struct multipath *m)
|
|
{
|
|
static struct param _params[] = {
|
|
{1, 1024, "invalid number of paths"},
|
|
{0, 1024, "invalid number of selector args"}
|
|
};
|
|
|
|
int r;
|
|
unsigned i, nr_selector_args, nr_params;
|
|
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 = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
nr_params = 1 + nr_selector_args;
|
|
for (i = 0; i < pg->nr_pgpaths; i++) {
|
|
struct pgpath *pgpath;
|
|
struct arg_set path_args;
|
|
|
|
if (as->argc < nr_params) {
|
|
ti->error = "not enough path parameters";
|
|
goto bad;
|
|
}
|
|
|
|
path_args.argc = nr_params;
|
|
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);
|
|
consume(as, nr_params);
|
|
}
|
|
|
|
return pg;
|
|
|
|
bad:
|
|
free_priority_group(pg, ti);
|
|
return ERR_PTR(r);
|
|
}
|
|
|
|
static int parse_hw_handler(struct arg_set *as, struct multipath *m)
|
|
{
|
|
unsigned hw_argc;
|
|
int ret;
|
|
struct dm_target *ti = m->ti;
|
|
|
|
static struct param _params[] = {
|
|
{0, 1024, "invalid number of hardware handler args"},
|
|
};
|
|
|
|
if (read_param(_params, shift(as), &hw_argc, &ti->error))
|
|
return -EINVAL;
|
|
|
|
if (!hw_argc)
|
|
return 0;
|
|
|
|
if (hw_argc > as->argc) {
|
|
ti->error = "not enough arguments for hardware handler";
|
|
return -EINVAL;
|
|
}
|
|
|
|
m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL);
|
|
request_module("scsi_dh_%s", m->hw_handler_name);
|
|
if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
|
|
ti->error = "unknown hardware handler type";
|
|
ret = -EINVAL;
|
|
goto fail;
|
|
}
|
|
|
|
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]);
|
|
}
|
|
consume(as, hw_argc - 1);
|
|
|
|
return 0;
|
|
fail:
|
|
kfree(m->hw_handler_name);
|
|
m->hw_handler_name = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static int parse_features(struct arg_set *as, struct multipath *m)
|
|
{
|
|
int r;
|
|
unsigned argc;
|
|
struct dm_target *ti = m->ti;
|
|
const char *param_name;
|
|
|
|
static struct param _params[] = {
|
|
{0, 3, "invalid number of feature args"},
|
|
{1, 50, "pg_init_retries must be between 1 and 50"},
|
|
};
|
|
|
|
r = read_param(_params, shift(as), &argc, &ti->error);
|
|
if (r)
|
|
return -EINVAL;
|
|
|
|
if (!argc)
|
|
return 0;
|
|
|
|
do {
|
|
param_name = shift(as);
|
|
argc--;
|
|
|
|
if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) {
|
|
r = queue_if_no_path(m, 1, 0);
|
|
continue;
|
|
}
|
|
|
|
if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
|
|
(argc >= 1)) {
|
|
r = read_param(_params + 1, shift(as),
|
|
&m->pg_init_retries, &ti->error);
|
|
argc--;
|
|
continue;
|
|
}
|
|
|
|
ti->error = "Unrecognised multipath feature request";
|
|
r = -EINVAL;
|
|
} while (argc && !r);
|
|
|
|
return r;
|
|
}
|
|
|
|
static int multipath_ctr(struct dm_target *ti, unsigned int argc,
|
|
char **argv)
|
|
{
|
|
/* target parameters */
|
|
static struct param _params[] = {
|
|
{1, 1024, "invalid number of priority groups"},
|
|
{1, 1024, "invalid initial priority group number"},
|
|
};
|
|
|
|
int r;
|
|
struct multipath *m;
|
|
struct 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 = parse_hw_handler(&as, m);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error);
|
|
if (r)
|
|
goto bad;
|
|
|
|
/* parse the priority groups */
|
|
while (as.argc) {
|
|
struct priority_group *pg;
|
|
|
|
pg = parse_priority_group(&as, m);
|
|
if (IS_ERR(pg)) {
|
|
r = PTR_ERR(pg);
|
|
goto bad;
|
|
}
|
|
|
|
m->nr_valid_paths += pg->nr_pgpaths;
|
|
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_requests = 1;
|
|
|
|
return 0;
|
|
|
|
bad:
|
|
free_multipath(m);
|
|
return r;
|
|
}
|
|
|
|
static void flush_multipath_work(void)
|
|
{
|
|
flush_workqueue(kmpath_handlerd);
|
|
flush_workqueue(kmultipathd);
|
|
flush_scheduled_work();
|
|
}
|
|
|
|
static void multipath_dtr(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
|
|
flush_multipath_work();
|
|
free_multipath(m);
|
|
}
|
|
|
|
/*
|
|
* Map cloned requests
|
|
*/
|
|
static int multipath_map(struct dm_target *ti, struct request *clone,
|
|
union map_info *map_context)
|
|
{
|
|
int r;
|
|
struct dm_mpath_io *mpio;
|
|
struct multipath *m = (struct multipath *) ti->private;
|
|
|
|
mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
|
|
if (!mpio)
|
|
/* ENOMEM, requeue */
|
|
return DM_MAPIO_REQUEUE;
|
|
memset(mpio, 0, sizeof(*mpio));
|
|
|
|
map_context->ptr = mpio;
|
|
clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
|
|
r = map_io(m, clone, mpio, 0);
|
|
if (r < 0 || r == DM_MAPIO_REQUEUE)
|
|
mempool_free(mpio, m->mpio_pool);
|
|
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* 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 = 0;
|
|
pgpath->fail_count++;
|
|
|
|
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, m->nr_valid_paths);
|
|
|
|
schedule_work(&m->trigger_event);
|
|
queue_work(kmultipathd, &pgpath->deactivate_path);
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Reinstate a previously-failed path
|
|
*/
|
|
static int reinstate_path(struct pgpath *pgpath)
|
|
{
|
|
int r = 0;
|
|
unsigned long flags;
|
|
struct multipath *m = pgpath->pg->m;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (pgpath->is_active)
|
|
goto out;
|
|
|
|
if (!pgpath->pg->ps.type->reinstate_path) {
|
|
DMWARN("Reinstate path not supported by path selector %s",
|
|
pgpath->pg->ps.type->name);
|
|
r = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
|
|
if (r)
|
|
goto out;
|
|
|
|
pgpath->is_active = 1;
|
|
|
|
if (!m->nr_valid_paths++ && m->queue_size) {
|
|
m->current_pgpath = NULL;
|
|
queue_work(kmultipathd, &m->process_queued_ios);
|
|
} else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) {
|
|
if (queue_work(kmpath_handlerd, &pgpath->activate_path))
|
|
m->pg_init_in_progress++;
|
|
}
|
|
|
|
dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
|
|
pgpath->path.dev->name, m->nr_valid_paths);
|
|
|
|
schedule_work(&m->trigger_event);
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
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 = 0;
|
|
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,
|
|
int 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;
|
|
|
|
if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
|
|
(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 = 0;
|
|
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, int bypassed)
|
|
{
|
|
struct priority_group *pg;
|
|
unsigned pgnum;
|
|
|
|
if (!pgstr || (sscanf(pgstr, "%u", &pgnum) != 1) || !pgnum ||
|
|
(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 int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
|
|
{
|
|
unsigned long flags;
|
|
int limit_reached = 0;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (m->pg_init_count <= m->pg_init_retries)
|
|
m->pg_init_required = 1;
|
|
else
|
|
limit_reached = 1;
|
|
|
|
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;
|
|
|
|
/* device or driver problems */
|
|
switch (errors) {
|
|
case SCSI_DH_OK:
|
|
break;
|
|
case SCSI_DH_NOSYS:
|
|
if (!m->hw_handler_name) {
|
|
errors = 0;
|
|
break;
|
|
}
|
|
DMERR("Cannot failover device because scsi_dh_%s was not "
|
|
"loaded.", m->hw_handler_name);
|
|
/*
|
|
* 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, 1);
|
|
break;
|
|
/* TODO: For SCSI_DH_RETRY we should wait a couple seconds */
|
|
case SCSI_DH_RETRY:
|
|
case SCSI_DH_IMM_RETRY:
|
|
case SCSI_DH_RES_TEMP_UNAVAIL:
|
|
if (pg_init_limit_reached(m, pgpath))
|
|
fail_path(pgpath);
|
|
errors = 0;
|
|
break;
|
|
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 (!m->pg_init_required) {
|
|
m->queue_io = 0;
|
|
pg->bypassed = 0;
|
|
}
|
|
|
|
m->pg_init_in_progress--;
|
|
if (!m->pg_init_in_progress)
|
|
queue_work(kmultipathd, &m->process_queued_ios);
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
}
|
|
|
|
static void activate_path(struct work_struct *work)
|
|
{
|
|
struct pgpath *pgpath =
|
|
container_of(work, struct pgpath, activate_path);
|
|
|
|
scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
|
|
pg_init_done, pgpath);
|
|
}
|
|
|
|
/*
|
|
* 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.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;
|
|
unsigned long flags;
|
|
|
|
if (!error && !clone->errors)
|
|
return 0; /* I/O complete */
|
|
|
|
if (error == -EOPNOTSUPP)
|
|
return error;
|
|
|
|
if (mpio->pgpath)
|
|
fail_path(mpio->pgpath);
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m))
|
|
r = -EIO;
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
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 = map_context->ptr;
|
|
struct pgpath *pgpath = mpio->pgpath;
|
|
struct path_selector *ps;
|
|
int r;
|
|
|
|
r = do_end_io(m, clone, error, mpio);
|
|
if (pgpath) {
|
|
ps = &pgpath->pg->ps;
|
|
if (ps->type->end_io)
|
|
ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
|
|
}
|
|
mempool_free(mpio, m->mpio_pool);
|
|
|
|
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 = (struct multipath *) ti->private;
|
|
|
|
queue_if_no_path(m, 0, 1);
|
|
}
|
|
|
|
static void multipath_postsuspend(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = ti->private;
|
|
|
|
mutex_lock(&m->work_mutex);
|
|
m->suspended = 1;
|
|
flush_multipath_work();
|
|
mutex_unlock(&m->work_mutex);
|
|
}
|
|
|
|
/*
|
|
* Restore the queue_if_no_path setting.
|
|
*/
|
|
static void multipath_resume(struct dm_target *ti)
|
|
{
|
|
struct multipath *m = (struct multipath *) ti->private;
|
|
unsigned long flags;
|
|
|
|
mutex_lock(&m->work_mutex);
|
|
m->suspended = 0;
|
|
mutex_unlock(&m->work_mutex);
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
m->queue_if_no_path = m->saved_queue_if_no_path;
|
|
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 int multipath_status(struct dm_target *ti, status_type_t type,
|
|
char *result, unsigned int maxlen)
|
|
{
|
|
int sz = 0;
|
|
unsigned long flags;
|
|
struct multipath *m = (struct multipath *) 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 ", m->queue_size, m->pg_init_count);
|
|
else {
|
|
DMEMIT("%u ", m->queue_if_no_path +
|
|
(m->pg_init_retries > 0) * 2);
|
|
if (m->queue_if_no_path)
|
|
DMEMIT("queue_if_no_path ");
|
|
if (m->pg_init_retries)
|
|
DMEMIT("pg_init_retries %u ", m->pg_init_retries);
|
|
}
|
|
|
|
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 = 1;
|
|
|
|
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);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
|
|
{
|
|
int r = -EINVAL;
|
|
struct dm_dev *dev;
|
|
struct multipath *m = (struct multipath *) ti->private;
|
|
action_fn action;
|
|
|
|
mutex_lock(&m->work_mutex);
|
|
|
|
if (m->suspended) {
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
if (dm_suspended(ti)) {
|
|
r = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
if (argc == 1) {
|
|
if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) {
|
|
r = queue_if_no_path(m, 1, 0);
|
|
goto out;
|
|
} else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) {
|
|
r = queue_if_no_path(m, 0, 0);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
if (argc != 2) {
|
|
DMWARN("Unrecognised multipath message received.");
|
|
goto out;
|
|
}
|
|
|
|
if (!strnicmp(argv[0], MESG_STR("disable_group"))) {
|
|
r = bypass_pg_num(m, argv[1], 1);
|
|
goto out;
|
|
} else if (!strnicmp(argv[0], MESG_STR("enable_group"))) {
|
|
r = bypass_pg_num(m, argv[1], 0);
|
|
goto out;
|
|
} else if (!strnicmp(argv[0], MESG_STR("switch_group"))) {
|
|
r = switch_pg_num(m, argv[1]);
|
|
goto out;
|
|
} else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
|
|
action = reinstate_path;
|
|
else if (!strnicmp(argv[0], MESG_STR("fail_path")))
|
|
action = fail_path;
|
|
else {
|
|
DMWARN("Unrecognised multipath message received.");
|
|
goto out;
|
|
}
|
|
|
|
r = dm_get_device(ti, argv[1], ti->begin, ti->len,
|
|
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_ioctl(struct dm_target *ti, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct multipath *m = (struct multipath *) ti->private;
|
|
struct block_device *bdev = NULL;
|
|
fmode_t mode = 0;
|
|
unsigned long flags;
|
|
int r = 0;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
if (!m->current_pgpath)
|
|
__choose_pgpath(m, 0);
|
|
|
|
if (m->current_pgpath) {
|
|
bdev = m->current_pgpath->path.dev->bdev;
|
|
mode = m->current_pgpath->path.dev->mode;
|
|
}
|
|
|
|
if (m->queue_io)
|
|
r = -EAGAIN;
|
|
else if (!bdev)
|
|
r = -EIO;
|
|
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
|
|
}
|
|
|
|
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 dm_underlying_device_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)
|
|
{
|
|
int busy = 0, has_active = 0;
|
|
struct multipath *m = ti->private;
|
|
struct priority_group *pg;
|
|
struct pgpath *pgpath;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&m->lock, flags);
|
|
|
|
/* Guess which priority_group will be used at next mapping time */
|
|
if (unlikely(!m->current_pgpath && m->next_pg))
|
|
pg = m->next_pg;
|
|
else if (likely(m->current_pg))
|
|
pg = m->current_pg;
|
|
else
|
|
/*
|
|
* 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.
|
|
*/
|
|
goto out;
|
|
|
|
/*
|
|
* 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 = 1;
|
|
list_for_each_entry(pgpath, &pg->pgpaths, list)
|
|
if (pgpath->is_active) {
|
|
has_active = 1;
|
|
|
|
if (!__pgpath_busy(pgpath)) {
|
|
busy = 0;
|
|
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 = 0;
|
|
|
|
out:
|
|
spin_unlock_irqrestore(&m->lock, flags);
|
|
|
|
return busy;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Module setup
|
|
*---------------------------------------------------------------*/
|
|
static struct target_type multipath_target = {
|
|
.name = "multipath",
|
|
.version = {1, 1, 1},
|
|
.module = THIS_MODULE,
|
|
.ctr = multipath_ctr,
|
|
.dtr = multipath_dtr,
|
|
.map_rq = multipath_map,
|
|
.rq_end_io = multipath_end_io,
|
|
.presuspend = multipath_presuspend,
|
|
.postsuspend = multipath_postsuspend,
|
|
.resume = multipath_resume,
|
|
.status = multipath_status,
|
|
.message = multipath_message,
|
|
.ioctl = multipath_ioctl,
|
|
.iterate_devices = multipath_iterate_devices,
|
|
.busy = multipath_busy,
|
|
};
|
|
|
|
static int __init dm_multipath_init(void)
|
|
{
|
|
int r;
|
|
|
|
/* allocate a slab for the dm_ios */
|
|
_mpio_cache = KMEM_CACHE(dm_mpath_io, 0);
|
|
if (!_mpio_cache)
|
|
return -ENOMEM;
|
|
|
|
r = dm_register_target(&multipath_target);
|
|
if (r < 0) {
|
|
DMERR("register failed %d", r);
|
|
kmem_cache_destroy(_mpio_cache);
|
|
return -EINVAL;
|
|
}
|
|
|
|
kmultipathd = create_workqueue("kmpathd");
|
|
if (!kmultipathd) {
|
|
DMERR("failed to create workqueue kmpathd");
|
|
dm_unregister_target(&multipath_target);
|
|
kmem_cache_destroy(_mpio_cache);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* 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 = create_singlethread_workqueue("kmpath_handlerd");
|
|
if (!kmpath_handlerd) {
|
|
DMERR("failed to create workqueue kmpath_handlerd");
|
|
destroy_workqueue(kmultipathd);
|
|
dm_unregister_target(&multipath_target);
|
|
kmem_cache_destroy(_mpio_cache);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
DMINFO("version %u.%u.%u loaded",
|
|
multipath_target.version[0], multipath_target.version[1],
|
|
multipath_target.version[2]);
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_multipath_exit(void)
|
|
{
|
|
destroy_workqueue(kmpath_handlerd);
|
|
destroy_workqueue(kmultipathd);
|
|
|
|
dm_unregister_target(&multipath_target);
|
|
kmem_cache_destroy(_mpio_cache);
|
|
}
|
|
|
|
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");
|