Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
new file mode 100644
index 0000000..43763a0
--- /dev/null
+++ b/drivers/md/dm-mpath.c
@@ -0,0 +1,1302 @@
+/*
+ * Copyright (C) 2003 Sistina Software Limited.
+ * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "dm-path-selector.h"
+#include "dm-hw-handler.h"
+#include "dm-bio-list.h"
+#include "dm-bio-record.h"
+
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/workqueue.h>
+#include <asm/atomic.h>
+
+#define MESG_STR(x) x, sizeof(x)
+
+/* Path properties */
+struct pgpath {
+ struct list_head list;
+
+ struct priority_group *pg; /* Owning PG */
+ unsigned fail_count; /* Cumulative failure count */
+
+ struct path path;
+};
+
+#define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
+
+/*
+ * Paths are grouped into Priority Groups and numbered from 1 upwards.
+ * Each has a path selector which controls which path gets used.
+ */
+struct priority_group {
+ struct list_head list;
+
+ struct multipath *m; /* Owning multipath instance */
+ struct path_selector ps;
+
+ unsigned pg_num; /* Reference number */
+ unsigned bypassed; /* Temporarily bypass this PG? */
+
+ unsigned nr_pgpaths; /* Number of paths in PG */
+ struct list_head pgpaths;
+};
+
+/* Multipath context */
+struct multipath {
+ struct list_head list;
+ struct dm_target *ti;
+
+ spinlock_t lock;
+
+ struct hw_handler hw_handler;
+ unsigned nr_priority_groups;
+ struct list_head priority_groups;
+ unsigned pg_init_required; /* pg_init needs calling? */
+
+ unsigned nr_valid_paths; /* Total number of usable paths */
+ struct pgpath *current_pgpath;
+ struct priority_group *current_pg;
+ struct priority_group *next_pg; /* Switch to this PG if set */
+ unsigned repeat_count; /* I/Os left before calling PS again */
+
+ unsigned queue_io; /* Must we queue all I/O? */
+ unsigned queue_if_no_path; /* Queue I/O if last path fails? */
+ unsigned suspended; /* Has dm core suspended our I/O? */
+
+ struct work_struct process_queued_ios;
+ struct bio_list queued_ios;
+ unsigned queue_size;
+
+ struct work_struct trigger_event;
+
+ /*
+ * We must use a mempool of mpath_io structs so that we
+ * can resubmit bios on error.
+ */
+ mempool_t *mpio_pool;
+};
+
+/*
+ * Context information attached to each bio we process.
+ */
+struct mpath_io {
+ struct pgpath *pgpath;
+ struct dm_bio_details details;
+};
+
+typedef int (*action_fn) (struct pgpath *pgpath);
+
+#define MIN_IOS 256 /* Mempool size */
+
+static kmem_cache_t *_mpio_cache;
+
+static void process_queued_ios(void *data);
+static void trigger_event(void *data);
+
+
+/*-----------------------------------------------
+ * Allocation routines
+ *-----------------------------------------------*/
+
+static struct pgpath *alloc_pgpath(void)
+{
+ struct pgpath *pgpath = kmalloc(sizeof(*pgpath), GFP_KERNEL);
+
+ if (pgpath) {
+ memset(pgpath, 0, sizeof(*pgpath));
+ pgpath->path.is_active = 1;
+ }
+
+ return pgpath;
+}
+
+static inline void free_pgpath(struct pgpath *pgpath)
+{
+ kfree(pgpath);
+}
+
+static struct priority_group *alloc_priority_group(void)
+{
+ struct priority_group *pg;
+
+ pg = kmalloc(sizeof(*pg), GFP_KERNEL);
+ if (!pg)
+ return NULL;
+
+ memset(pg, 0, sizeof(*pg));
+ INIT_LIST_HEAD(&pg->pgpaths);
+
+ return pg;
+}
+
+static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
+{
+ struct pgpath *pgpath, *tmp;
+
+ list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
+ list_del(&pgpath->list);
+ dm_put_device(ti, pgpath->path.dev);
+ free_pgpath(pgpath);
+ }
+}
+
+static void free_priority_group(struct priority_group *pg,
+ struct dm_target *ti)
+{
+ struct path_selector *ps = &pg->ps;
+
+ if (ps->type) {
+ ps->type->destroy(ps);
+ dm_put_path_selector(ps->type);
+ }
+
+ free_pgpaths(&pg->pgpaths, ti);
+ kfree(pg);
+}
+
+static struct multipath *alloc_multipath(void)
+{
+ struct multipath *m;
+
+ m = kmalloc(sizeof(*m), GFP_KERNEL);
+ if (m) {
+ memset(m, 0, sizeof(*m));
+ INIT_LIST_HEAD(&m->priority_groups);
+ spin_lock_init(&m->lock);
+ m->queue_io = 1;
+ INIT_WORK(&m->process_queued_ios, process_queued_ios, m);
+ INIT_WORK(&m->trigger_event, trigger_event, m);
+ m->mpio_pool = mempool_create(MIN_IOS, mempool_alloc_slab,
+ mempool_free_slab, _mpio_cache);
+ if (!m->mpio_pool) {
+ kfree(m);
+ return NULL;
+ }
+ }
+
+ return m;
+}
+
+static void free_multipath(struct multipath *m)
+{
+ struct priority_group *pg, *tmp;
+ struct hw_handler *hwh = &m->hw_handler;
+
+ list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
+ list_del(&pg->list);
+ free_priority_group(pg, m->ti);
+ }
+
+ if (hwh->type) {
+ hwh->type->destroy(hwh);
+ dm_put_hw_handler(hwh->type);
+ }
+
+ mempool_destroy(m->mpio_pool);
+ kfree(m);
+}
+
+
+/*-----------------------------------------------
+ * Path selection
+ *-----------------------------------------------*/
+
+static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
+{
+ struct hw_handler *hwh = &m->hw_handler;
+
+ m->current_pg = pgpath->pg;
+
+ /* Must we initialise the PG first, and queue I/O till it's ready? */
+ if (hwh->type && hwh->type->pg_init) {
+ m->pg_init_required = 1;
+ m->queue_io = 1;
+ } else {
+ m->pg_init_required = 0;
+ m->queue_io = 0;
+ }
+}
+
+static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
+{
+ struct path *path;
+
+ path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
+ if (!path)
+ return -ENXIO;
+
+ m->current_pgpath = path_to_pgpath(path);
+
+ if (m->current_pg != pg)
+ __switch_pg(m, m->current_pgpath);
+
+ return 0;
+}
+
+static void __choose_pgpath(struct multipath *m)
+{
+ struct priority_group *pg;
+ unsigned bypassed = 1;
+
+ if (!m->nr_valid_paths)
+ goto failed;
+
+ /* Were we instructed to switch PG? */
+ if (m->next_pg) {
+ pg = m->next_pg;
+ m->next_pg = NULL;
+ if (!__choose_path_in_pg(m, pg))
+ return;
+ }
+
+ /* Don't change PG until it has no remaining paths */
+ if (m->current_pg && !__choose_path_in_pg(m, m->current_pg))
+ return;
+
+ /*
+ * Loop through priority groups until we find a valid path.
+ * First time we skip PGs marked 'bypassed'.
+ * Second time we only try the ones we skipped.
+ */
+ do {
+ list_for_each_entry(pg, &m->priority_groups, list) {
+ if (pg->bypassed == bypassed)
+ continue;
+ if (!__choose_path_in_pg(m, pg))
+ return;
+ }
+ } while (bypassed--);
+
+failed:
+ m->current_pgpath = NULL;
+ m->current_pg = NULL;
+}
+
+static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
+ unsigned was_queued)
+{
+ int r = 1;
+ unsigned long flags;
+ struct pgpath *pgpath;
+
+ spin_lock_irqsave(&m->lock, flags);
+
+ /* Do we need to select a new pgpath? */
+ if (!m->current_pgpath ||
+ (!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
+ __choose_pgpath(m);
+
+ pgpath = m->current_pgpath;
+
+ if (was_queued)
+ m->queue_size--;
+
+ if ((pgpath && m->queue_io) ||
+ (!pgpath && m->queue_if_no_path && !m->suspended)) {
+ /* Queue for the daemon to resubmit */
+ bio_list_add(&m->queued_ios, bio);
+ m->queue_size++;
+ if (m->pg_init_required || !m->queue_io)
+ schedule_work(&m->process_queued_ios);
+ pgpath = NULL;
+ r = 0;
+ } else if (!pgpath)
+ r = -EIO; /* Failed */
+ else
+ bio->bi_bdev = pgpath->path.dev->bdev;
+
+ mpio->pgpath = pgpath;
+
+ spin_unlock_irqrestore(&m->lock, flags);
+
+ return r;
+}
+
+/*
+ * If we run out of usable paths, should we queue I/O or error it?
+ */
+static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&m->lock, flags);
+
+ m->queue_if_no_path = queue_if_no_path;
+ if (!m->queue_if_no_path)
+ schedule_work(&m->process_queued_ios);
+
+ spin_unlock_irqrestore(&m->lock, flags);
+
+ return 0;
+}
+
+/*-----------------------------------------------------------------
+ * The multipath daemon is responsible for resubmitting queued ios.
+ *---------------------------------------------------------------*/
+
+static void dispatch_queued_ios(struct multipath *m)
+{
+ int r;
+ unsigned long flags;
+ struct bio *bio = NULL, *next;
+ struct mpath_io *mpio;
+ union map_info *info;
+
+ spin_lock_irqsave(&m->lock, flags);
+ bio = bio_list_get(&m->queued_ios);
+ spin_unlock_irqrestore(&m->lock, flags);
+
+ while (bio) {
+ next = bio->bi_next;
+ bio->bi_next = NULL;
+
+ info = dm_get_mapinfo(bio);
+ mpio = info->ptr;
+
+ r = map_io(m, bio, mpio, 1);
+ if (r < 0)
+ bio_endio(bio, bio->bi_size, r);
+ else if (r == 1)
+ generic_make_request(bio);
+
+ bio = next;
+ }
+}
+
+static void process_queued_ios(void *data)
+{
+ struct multipath *m = (struct multipath *) data;
+ struct hw_handler *hwh = &m->hw_handler;
+ struct pgpath *pgpath;
+ unsigned init_required, must_queue = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&m->lock, flags);
+
+ if (!m->current_pgpath)
+ __choose_pgpath(m);
+
+ pgpath = m->current_pgpath;
+
+ if ((pgpath && m->queue_io) ||
+ (!pgpath && m->queue_if_no_path && !m->suspended))
+ must_queue = 1;
+
+ init_required = m->pg_init_required;
+ if (init_required)
+ m->pg_init_required = 0;
+
+ spin_unlock_irqrestore(&m->lock, flags);
+
+ if (init_required)
+ hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path);
+
+ if (!must_queue)
+ dispatch_queued_ios(m);
+}
+
+/*
+ * An event is triggered whenever a path is taken out of use.
+ * Includes path failure and PG bypass.
+ */
+static void trigger_event(void *data)
+{
+ struct multipath *m = (struct multipath *) data;
+
+ 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>]* ]+ ]+
+ *---------------------------------------------------------------*/
+struct param {
+ unsigned min;
+ unsigned max;
+ char *error;
+};
+
+#define ESTR(s) ("dm-multipath: " s)
+
+static int read_param(struct param *param, char *str, unsigned *v, char **error)
+{
+ if (!str ||
+ (sscanf(str, "%u", v) != 1) ||
+ (*v < param->min) ||
+ (*v > param->max)) {
+ *error = param->error;
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+struct arg_set {
+ unsigned argc;
+ char **argv;
+};
+
+static char *shift(struct arg_set *as)
+{
+ char *r;
+
+ if (as->argc) {
+ as->argc--;
+ r = *as->argv;
+ as->argv++;
+ return r;
+ }
+
+ return NULL;
+}
+
+static void consume(struct arg_set *as, unsigned n)
+{
+ 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, ESTR("invalid number of path selector args")},
+ };
+
+ pst = dm_get_path_selector(shift(as));
+ if (!pst) {
+ ti->error = ESTR("unknown path selector type");
+ return -EINVAL;
+ }
+
+ r = read_param(_params, shift(as), &ps_argc, &ti->error);
+ if (r)
+ return -EINVAL;
+
+ r = pst->create(&pg->ps, ps_argc, as->argv);
+ if (r) {
+ dm_put_path_selector(pst);
+ ti->error = ESTR("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;
+
+ /* we need at least a path arg */
+ if (as->argc < 1) {
+ ti->error = ESTR("no device given");
+ return NULL;
+ }
+
+ p = alloc_pgpath();
+ if (!p)
+ return NULL;
+
+ r = dm_get_device(ti, shift(as), ti->begin, ti->len,
+ dm_table_get_mode(ti->table), &p->path.dev);
+ if (r) {
+ ti->error = ESTR("error getting device");
+ 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 NULL;
+}
+
+static struct priority_group *parse_priority_group(struct arg_set *as,
+ struct multipath *m,
+ struct dm_target *ti)
+{
+ static struct param _params[] = {
+ {1, 1024, ESTR("invalid number of paths")},
+ {0, 1024, ESTR("invalid number of selector args")}
+ };
+
+ int r;
+ unsigned i, nr_selector_args, nr_params;
+ struct priority_group *pg;
+
+ if (as->argc < 2) {
+ as->argc = 0;
+ ti->error = ESTR("not enough priority group aruments");
+ return NULL;
+ }
+
+ pg = alloc_priority_group();
+ if (!pg) {
+ ti->error = ESTR("couldn't allocate priority group");
+ return NULL;
+ }
+ 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)
+ goto bad;
+
+ path_args.argc = nr_params;
+ path_args.argv = as->argv;
+
+ pgpath = parse_path(&path_args, &pg->ps, ti);
+ if (!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 NULL;
+}
+
+static int parse_hw_handler(struct arg_set *as, struct multipath *m,
+ struct dm_target *ti)
+{
+ int r;
+ struct hw_handler_type *hwht;
+ unsigned hw_argc;
+
+ static struct param _params[] = {
+ {0, 1024, ESTR("invalid number of hardware handler args")},
+ };
+
+ r = read_param(_params, shift(as), &hw_argc, &ti->error);
+ if (r)
+ return -EINVAL;
+
+ if (!hw_argc)
+ return 0;
+
+ hwht = dm_get_hw_handler(shift(as));
+ if (!hwht) {
+ ti->error = ESTR("unknown hardware handler type");
+ return -EINVAL;
+ }
+
+ r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
+ if (r) {
+ dm_put_hw_handler(hwht);
+ ti->error = ESTR("hardware handler constructor failed");
+ return r;
+ }
+
+ m->hw_handler.type = hwht;
+ consume(as, hw_argc - 1);
+
+ return 0;
+}
+
+static int parse_features(struct arg_set *as, struct multipath *m,
+ struct dm_target *ti)
+{
+ int r;
+ unsigned argc;
+
+ static struct param _params[] = {
+ {0, 1, ESTR("invalid number of feature args")},
+ };
+
+ r = read_param(_params, shift(as), &argc, &ti->error);
+ if (r)
+ return -EINVAL;
+
+ if (!argc)
+ return 0;
+
+ if (!strnicmp(shift(as), MESG_STR("queue_if_no_path")))
+ return queue_if_no_path(m, 1);
+ else {
+ ti->error = "Unrecognised multipath feature request";
+ return -EINVAL;
+ }
+}
+
+static int multipath_ctr(struct dm_target *ti, unsigned int argc,
+ char **argv)
+{
+ /* target parameters */
+ static struct param _params[] = {
+ {1, 1024, ESTR("invalid number of priority groups")},
+ {1, 1024, ESTR("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();
+ if (!m) {
+ ti->error = ESTR("can't allocate multipath");
+ return -EINVAL;
+ }
+
+ r = parse_features(&as, m, ti);
+ if (r)
+ goto bad;
+
+ r = parse_hw_handler(&as, m, ti);
+ 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, ti);
+ if (!pg) {
+ r = -EINVAL;
+ 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 = ESTR("priority group count mismatch");
+ r = -EINVAL;
+ goto bad;
+ }
+
+ ti->private = m;
+ m->ti = ti;
+
+ return 0;
+
+ bad:
+ free_multipath(m);
+ return r;
+}
+
+static void multipath_dtr(struct dm_target *ti)
+{
+ struct multipath *m = (struct multipath *) ti->private;
+ free_multipath(m);
+}
+
+/*
+ * Map bios, recording original fields for later in case we have to resubmit
+ */
+static int multipath_map(struct dm_target *ti, struct bio *bio,
+ union map_info *map_context)
+{
+ int r;
+ struct mpath_io *mpio;
+ struct multipath *m = (struct multipath *) ti->private;
+
+ mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
+ dm_bio_record(&mpio->details, bio);
+
+ map_context->ptr = mpio;
+ bio->bi_rw |= (1 << BIO_RW_FAILFAST);
+ r = map_io(m, bio, mpio, 0);
+ if (r < 0)
+ 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->path.is_active)
+ goto out;
+
+ DMWARN("dm-multipath: Failing path %s.", pgpath->path.dev->name);
+
+ pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
+ pgpath->path.is_active = 0;
+ pgpath->fail_count++;
+
+ m->nr_valid_paths--;
+
+ if (pgpath == m->current_pgpath)
+ m->current_pgpath = NULL;
+
+ 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;
+ unsigned long flags;
+ struct multipath *m = pgpath->pg->m;
+
+ spin_lock_irqsave(&m->lock, flags);
+
+ if (pgpath->path.is_active)
+ goto out;
+
+ if (!pgpath->pg->ps.type) {
+ 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->path.is_active = 1;
+
+ m->current_pgpath = NULL;
+ if (!m->nr_valid_paths++)
+ schedule_work(&m->process_queued_ios);
+
+ 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;
+}
+
+/*
+ * pg_init must call this when it has completed its initialisation
+ */
+void dm_pg_init_complete(struct path *path, unsigned err_flags)
+{
+ struct pgpath *pgpath = path_to_pgpath(path);
+ struct priority_group *pg = pgpath->pg;
+ struct multipath *m = pg->m;
+ unsigned long flags;
+
+ /* We insist on failing the path if the PG is already bypassed. */
+ if (err_flags && pg->bypassed)
+ err_flags |= MP_FAIL_PATH;
+
+ if (err_flags & MP_FAIL_PATH)
+ fail_path(pgpath);
+
+ if (err_flags & MP_BYPASS_PG)
+ bypass_pg(m, pg, 1);
+
+ spin_lock_irqsave(&m->lock, flags);
+ if (!err_flags)
+ m->queue_io = 0;
+ else {
+ m->current_pgpath = NULL;
+ m->current_pg = NULL;
+ }
+ schedule_work(&m->process_queued_ios);
+ spin_unlock_irqrestore(&m->lock, flags);
+}
+
+/*
+ * end_io handling
+ */
+static int do_end_io(struct multipath *m, struct bio *bio,
+ int error, struct mpath_io *mpio)
+{
+ struct hw_handler *hwh = &m->hw_handler;
+ unsigned err_flags = MP_FAIL_PATH; /* Default behavior */
+
+ if (!error)
+ return 0; /* I/O complete */
+
+ spin_lock(&m->lock);
+ if (!m->nr_valid_paths) {
+ if (!m->queue_if_no_path || m->suspended) {
+ spin_unlock(&m->lock);
+ return -EIO;
+ } else {
+ spin_unlock(&m->lock);
+ goto requeue;
+ }
+ }
+ spin_unlock(&m->lock);
+
+ if (hwh->type && hwh->type->error)
+ err_flags = hwh->type->error(hwh, bio);
+
+ if (mpio->pgpath) {
+ if (err_flags & MP_FAIL_PATH)
+ fail_path(mpio->pgpath);
+
+ if (err_flags & MP_BYPASS_PG)
+ bypass_pg(m, mpio->pgpath->pg, 1);
+ }
+
+ if (err_flags & MP_ERROR_IO)
+ return -EIO;
+
+ requeue:
+ dm_bio_restore(&mpio->details, bio);
+
+ /* queue for the daemon to resubmit or fail */
+ spin_lock(&m->lock);
+ bio_list_add(&m->queued_ios, bio);
+ m->queue_size++;
+ if (!m->queue_io)
+ schedule_work(&m->process_queued_ios);
+ spin_unlock(&m->lock);
+
+ return 1; /* io not complete */
+}
+
+static int multipath_end_io(struct dm_target *ti, struct bio *bio,
+ int error, union map_info *map_context)
+{
+ struct multipath *m = (struct multipath *) ti->private;
+ struct mpath_io *mpio = (struct mpath_io *) map_context->ptr;
+ struct pgpath *pgpath = mpio->pgpath;
+ struct path_selector *ps;
+ int r;
+
+ r = do_end_io(m, bio, error, mpio);
+ if (pgpath) {
+ ps = &pgpath->pg->ps;
+ if (ps->type->end_io)
+ ps->type->end_io(ps, &pgpath->path);
+ }
+ if (r <= 0)
+ mempool_free(mpio, m->mpio_pool);
+
+ return r;
+}
+
+/*
+ * Suspend can't complete until all the I/O is processed so if
+ * the last path failed we will now error any queued I/O.
+ */
+static void multipath_presuspend(struct dm_target *ti)
+{
+ struct multipath *m = (struct multipath *) ti->private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&m->lock, flags);
+ m->suspended = 1;
+ if (m->queue_if_no_path)
+ schedule_work(&m->process_queued_ios);
+ spin_unlock_irqrestore(&m->lock, flags);
+}
+
+static void multipath_resume(struct dm_target *ti)
+{
+ struct multipath *m = (struct multipath *) ti->private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&m->lock, flags);
+ m->suspended = 0;
+ 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 hw_handler *hwh = &m->hw_handler;
+ struct priority_group *pg;
+ struct pgpath *p;
+ unsigned pg_num;
+ char state;
+
+ spin_lock_irqsave(&m->lock, flags);
+
+ /* Features */
+ if (type == STATUSTYPE_INFO)
+ DMEMIT("1 %u ", m->queue_size);
+ else if (m->queue_if_no_path)
+ DMEMIT("1 queue_if_no_path ");
+ else
+ DMEMIT("0 ");
+
+ if (hwh->type && hwh->type->status)
+ sz += hwh->type->status(hwh, type, result + sz, maxlen - sz);
+ else if (!hwh->type || type == STATUSTYPE_INFO)
+ DMEMIT("0 ");
+ else
+ DMEMIT("1 %s ", hwh->type->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->path.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;
+ struct dm_dev *dev;
+ struct multipath *m = (struct multipath *) ti->private;
+ action_fn action;
+
+ if (argc == 1) {
+ if (!strnicmp(argv[0], MESG_STR("queue_if_no_path")))
+ return queue_if_no_path(m, 1);
+ else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path")))
+ return queue_if_no_path(m, 0);
+ }
+
+ if (argc != 2)
+ goto error;
+
+ if (!strnicmp(argv[0], MESG_STR("disable_group")))
+ return bypass_pg_num(m, argv[1], 1);
+ else if (!strnicmp(argv[0], MESG_STR("enable_group")))
+ return bypass_pg_num(m, argv[1], 0);
+ else if (!strnicmp(argv[0], MESG_STR("switch_group")))
+ return switch_pg_num(m, argv[1]);
+ 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
+ goto error;
+
+ r = dm_get_device(ti, argv[1], ti->begin, ti->len,
+ dm_table_get_mode(ti->table), &dev);
+ if (r) {
+ DMWARN("dm-multipath message: error getting device %s",
+ argv[1]);
+ return -EINVAL;
+ }
+
+ r = action_dev(m, dev, action);
+
+ dm_put_device(ti, dev);
+
+ return r;
+
+error:
+ DMWARN("Unrecognised multipath message received.");
+ return -EINVAL;
+}
+
+/*-----------------------------------------------------------------
+ * Module setup
+ *---------------------------------------------------------------*/
+static struct target_type multipath_target = {
+ .name = "multipath",
+ .version = {1, 0, 4},
+ .module = THIS_MODULE,
+ .ctr = multipath_ctr,
+ .dtr = multipath_dtr,
+ .map = multipath_map,
+ .end_io = multipath_end_io,
+ .presuspend = multipath_presuspend,
+ .resume = multipath_resume,
+ .status = multipath_status,
+ .message = multipath_message,
+};
+
+static int __init dm_multipath_init(void)
+{
+ int r;
+
+ /* allocate a slab for the dm_ios */
+ _mpio_cache = kmem_cache_create("dm_mpath", sizeof(struct mpath_io),
+ 0, 0, NULL, NULL);
+ if (!_mpio_cache)
+ return -ENOMEM;
+
+ r = dm_register_target(&multipath_target);
+ if (r < 0) {
+ DMERR("%s: register failed %d", multipath_target.name, r);
+ kmem_cache_destroy(_mpio_cache);
+ return -EINVAL;
+ }
+
+ DMINFO("dm-multipath 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)
+{
+ int r;
+
+ r = dm_unregister_target(&multipath_target);
+ if (r < 0)
+ DMERR("%s: target unregister failed %d",
+ multipath_target.name, r);
+ kmem_cache_destroy(_mpio_cache);
+}
+
+EXPORT_SYMBOL_GPL(dm_pg_init_complete);
+
+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");