#include <linux/device-mapper.h>
#include "dm-path-selector.h"
-#include "dm-bio-record.h"
#include "dm-uevent.h"
#include <linux/ctype.h>
struct dm_path path;
struct work_struct deactivate_path;
+ struct work_struct activate_path;
};
#define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
spinlock_t lock;
const char *hw_handler_name;
- struct work_struct activate_path;
- struct pgpath *pgpath_to_activate;
unsigned nr_priority_groups;
struct list_head priority_groups;
unsigned pg_init_required; /* pg_init needs calling? */
unsigned pg_init_count; /* Number of times pg_init called */
struct work_struct process_queued_ios;
- struct bio_list queued_ios;
+ struct list_head queued_ios;
unsigned queue_size;
struct work_struct trigger_event;
*/
struct dm_mpath_io {
struct pgpath *pgpath;
- struct dm_bio_details details;
+ size_t nr_bytes;
};
typedef int (*action_fn) (struct pgpath *pgpath);
if (pgpath) {
pgpath->is_active = 1;
INIT_WORK(&pgpath->deactivate_path, deactivate_path);
+ INIT_WORK(&pgpath->activate_path, activate_path);
}
return pgpath;
static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
{
- unsigned long flags;
struct pgpath *pgpath, *tmp;
struct multipath *m = ti->private;
if (m->hw_handler_name)
scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev));
dm_put_device(ti, pgpath->path.dev);
- spin_lock_irqsave(&m->lock, flags);
- if (m->pgpath_to_activate == pgpath)
- m->pgpath_to_activate = NULL;
- spin_unlock_irqrestore(&m->lock, flags);
free_pgpath(pgpath);
}
}
m = kzalloc(sizeof(*m), GFP_KERNEL);
if (m) {
INIT_LIST_HEAD(&m->priority_groups);
+ INIT_LIST_HEAD(&m->queued_ios);
spin_lock_init(&m->lock);
m->queue_io = 1;
INIT_WORK(&m->process_queued_ios, process_queued_ios);
INIT_WORK(&m->trigger_event, trigger_event);
- INIT_WORK(&m->activate_path, activate_path);
m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
if (!m->mpio_pool) {
kfree(m);
m->pg_init_count = 0;
}
-static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
+static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg,
+ size_t nr_bytes)
{
struct dm_path *path;
- path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
+ path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes);
if (!path)
return -ENXIO;
return 0;
}
-static void __choose_pgpath(struct multipath *m)
+static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
{
struct priority_group *pg;
unsigned bypassed = 1;
if (m->next_pg) {
pg = m->next_pg;
m->next_pg = NULL;
- if (!__choose_path_in_pg(m, pg))
+ if (!__choose_path_in_pg(m, pg, nr_bytes))
return;
}
/* Don't change PG until it has no remaining paths */
- if (m->current_pg && !__choose_path_in_pg(m, m->current_pg))
+ if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes))
return;
/*
list_for_each_entry(pg, &m->priority_groups, list) {
if (pg->bypassed == bypassed)
continue;
- if (!__choose_path_in_pg(m, pg))
+ if (!__choose_path_in_pg(m, pg, nr_bytes))
return;
}
} while (bypassed--);
dm_noflush_suspending(m->ti));
}
-static int map_io(struct multipath *m, struct bio *bio,
+static int map_io(struct multipath *m, struct request *clone,
struct dm_mpath_io *mpio, unsigned was_queued)
{
int r = DM_MAPIO_REMAPPED;
+ size_t nr_bytes = blk_rq_bytes(clone);
unsigned long flags;
struct pgpath *pgpath;
+ struct block_device *bdev;
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);
+ __choose_pgpath(m, nr_bytes);
pgpath = m->current_pgpath;
if ((pgpath && m->queue_io) ||
(!pgpath && m->queue_if_no_path)) {
/* Queue for the daemon to resubmit */
- bio_list_add(&m->queued_ios, bio);
+ list_add_tail(&clone->queuelist, &m->queued_ios);
m->queue_size++;
if ((m->pg_init_required && !m->pg_init_in_progress) ||
!m->queue_io)
queue_work(kmultipathd, &m->process_queued_ios);
pgpath = NULL;
r = DM_MAPIO_SUBMITTED;
- } else if (pgpath)
- bio->bi_bdev = pgpath->path.dev->bdev;
- else if (__must_push_back(m))
+ } else if (pgpath) {
+ bdev = pgpath->path.dev->bdev;
+ clone->q = bdev_get_queue(bdev);
+ clone->rq_disk = bdev->bd_disk;
+ } else if (__must_push_back(m))
r = DM_MAPIO_REQUEUE;
else
r = -EIO; /* Failed */
mpio->pgpath = pgpath;
+ mpio->nr_bytes = nr_bytes;
+
+ if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io)
+ pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path,
+ nr_bytes);
spin_unlock_irqrestore(&m->lock, flags);
{
int r;
unsigned long flags;
- struct bio *bio = NULL, *next;
struct dm_mpath_io *mpio;
union map_info *info;
+ struct request *clone, *n;
+ LIST_HEAD(cl);
spin_lock_irqsave(&m->lock, flags);
- bio = bio_list_get(&m->queued_ios);
+ list_splice_init(&m->queued_ios, &cl);
spin_unlock_irqrestore(&m->lock, flags);
- while (bio) {
- next = bio->bi_next;
- bio->bi_next = NULL;
+ list_for_each_entry_safe(clone, n, &cl, queuelist) {
+ list_del_init(&clone->queuelist);
- info = dm_get_mapinfo(bio);
+ info = dm_get_rq_mapinfo(clone);
mpio = info->ptr;
- r = map_io(m, bio, mpio, 1);
- if (r < 0)
- bio_endio(bio, r);
- else if (r == DM_MAPIO_REMAPPED)
- generic_make_request(bio);
- else if (r == DM_MAPIO_REQUEUE)
- bio_endio(bio, -EIO);
-
- bio = next;
+ r = map_io(m, clone, mpio, 1);
+ if (r < 0) {
+ mempool_free(mpio, m->mpio_pool);
+ dm_kill_unmapped_request(clone, r);
+ } else if (r == DM_MAPIO_REMAPPED)
+ dm_dispatch_request(clone);
+ else if (r == DM_MAPIO_REQUEUE) {
+ mempool_free(mpio, m->mpio_pool);
+ dm_requeue_unmapped_request(clone);
+ }
}
}
{
struct multipath *m =
container_of(work, struct multipath, process_queued_ios);
- struct pgpath *pgpath = NULL;
- unsigned init_required = 0, must_queue = 1;
+ struct pgpath *pgpath = NULL, *tmp;
+ unsigned must_queue = 1;
unsigned long flags;
spin_lock_irqsave(&m->lock, flags);
goto out;
if (!m->current_pgpath)
- __choose_pgpath(m);
+ __choose_pgpath(m, 0);
pgpath = m->current_pgpath;
must_queue = 0;
if (m->pg_init_required && !m->pg_init_in_progress && pgpath) {
- m->pgpath_to_activate = pgpath;
m->pg_init_count++;
m->pg_init_required = 0;
- m->pg_init_in_progress = 1;
- init_required = 1;
+ list_for_each_entry(tmp, &pgpath->pg->pgpaths, list) {
+ if (queue_work(kmpath_handlerd, &tmp->activate_path))
+ m->pg_init_in_progress++;
+ }
}
-
out:
spin_unlock_irqrestore(&m->lock, flags);
-
- if (init_required)
- queue_work(kmpath_handlerd, &m->activate_path);
-
if (!must_queue)
dispatch_queued_ios(m);
}
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);
}
if (m->hw_handler_name) {
- r = scsi_dh_attach(bdev_get_queue(p->path.dev->bdev),
- 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 (!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) {
goto bad;
}
+ ti->num_flush_requests = 1;
+
return 0;
bad:
flush_workqueue(kmpath_handlerd);
flush_workqueue(kmultipathd);
+ flush_scheduled_work();
free_multipath(m);
}
/*
- * Map bios, recording original fields for later in case we have to resubmit
+ * Map cloned requests
*/
-static int multipath_map(struct dm_target *ti, struct bio *bio,
+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_NOIO);
- dm_bio_record(&mpio->details, bio);
+ 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;
- bio->bi_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT);
- r = map_io(m, bio, mpio, 0);
+ 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);
pgpath->is_active = 1;
- m->current_pgpath = NULL;
- if (!m->nr_valid_paths++ && m->queue_size)
+ 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);
spin_lock_irqsave(&m->lock, flags);
if (errors) {
- DMERR("Could not failover device. Error %d.", errors);
- m->current_pgpath = NULL;
- m->current_pg = NULL;
+ 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 = 0;
- queue_work(kmultipathd, &m->process_queued_ios);
+ 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)
{
int ret;
- struct multipath *m =
- container_of(work, struct multipath, activate_path);
- struct dm_path *path;
- unsigned long flags;
+ struct pgpath *pgpath =
+ container_of(work, struct pgpath, activate_path);
- spin_lock_irqsave(&m->lock, flags);
- path = &m->pgpath_to_activate->path;
- m->pgpath_to_activate = NULL;
- spin_unlock_irqrestore(&m->lock, flags);
- if (!path)
- return;
- ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev));
- pg_init_done(path, ret);
+ ret = scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev));
+ pg_init_done(&pgpath->path, ret);
}
/*
* end_io handling
*/
-static int do_end_io(struct multipath *m, struct bio *bio,
+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)
+ if (!error && !clone->errors)
return 0; /* I/O complete */
- if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
- return error;
-
if (error == -EOPNOTSUPP)
return error;
- spin_lock_irqsave(&m->lock, flags);
- if (!m->nr_valid_paths) {
- if (__must_push_back(m)) {
- spin_unlock_irqrestore(&m->lock, flags);
- return DM_ENDIO_REQUEUE;
- } else if (!m->queue_if_no_path) {
- spin_unlock_irqrestore(&m->lock, flags);
- return -EIO;
- } else {
- spin_unlock_irqrestore(&m->lock, flags);
- goto requeue;
- }
- }
- spin_unlock_irqrestore(&m->lock, flags);
-
if (mpio->pgpath)
fail_path(mpio->pgpath);
- requeue:
- dm_bio_restore(&mpio->details, bio);
-
- /* queue for the daemon to resubmit or fail */
spin_lock_irqsave(&m->lock, flags);
- bio_list_add(&m->queued_ios, bio);
- m->queue_size++;
- if (!m->queue_io)
- queue_work(kmultipathd, &m->process_queued_ios);
+ if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m))
+ r = -EIO;
spin_unlock_irqrestore(&m->lock, flags);
- return DM_ENDIO_INCOMPLETE; /* io not complete */
+ return r;
}
-static int multipath_end_io(struct dm_target *ti, struct bio *bio,
+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 path_selector *ps;
int r;
- r = do_end_io(m, bio, error, mpio);
+ 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);
+ ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
}
- if (r != DM_ENDIO_INCOMPLETE)
- mempool_free(mpio, m->mpio_pool);
+ mempool_free(mpio, m->mpio_pool);
return r;
}
spin_lock_irqsave(&m->lock, flags);
if (!m->current_pgpath)
- __choose_pgpath(m);
+ __choose_pgpath(m, 0);
if (m->current_pgpath) {
bdev = m->current_pgpath->path.dev->bdev;
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, 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, 0, 5},
+ .version = {1, 1, 0},
.module = THIS_MODULE,
.ctr = multipath_ctr,
.dtr = multipath_dtr,
- .map = multipath_map,
- .end_io = multipath_end_io,
+ .map_rq = multipath_map,
+ .rq_end_io = multipath_end_io,
.presuspend = multipath_presuspend,
.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)
git.openpandora.org / pandora-kernel.git / blobdiff