03-ps-init-fn.patch - this adds the ps-init function.
drivers/md/dm-mpath.c | 246 ++++++++++++++++++++++++++++++------------
drivers/md/dm-path-selector.c | 8 -
drivers/md/dm-path-selector.h | 23 +++
drivers/md/dm.c | 9 +
include/linux/device-mapper.h | 2
5 files changed, 211 insertions(+), 77 deletions(-)
--
Mike Christie
mikenc@xxxxxxxxxx
diff -aurp linux-2.6.6/drivers/md/dm.c linux-2.6.6-work/drivers/md/dm.c
--- linux-2.6.6/drivers/md/dm.c 2004-05-22 21:26:49.000000000 -0700
+++ linux-2.6.6-work/drivers/md/dm.c 2004-05-23 02:30:07.511500132 -0700
@@ -1078,6 +1078,15 @@ int dm_suspended(struct mapped_device *m
return test_bit(DMF_SUSPENDED, &md->flags);
}
+inline union map_info *dm_get_mapinfo(struct bio *bio)
+{
+ if (bio && bio->bi_private)
+ return &((struct target_io *)bio->bi_private)->info;
+ return NULL;
+}
+
+EXPORT_SYMBOL(dm_get_mapinfo);
+
struct block_device_operations dm_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
diff -aurp linux-2.6.6/drivers/md/dm-mpath.c linux-2.6.6-work/drivers/md/dm-mpath.c
--- linux-2.6.6/drivers/md/dm-mpath.c 2004-05-23 02:29:58.781624421 -0700
+++ linux-2.6.6-work/drivers/md/dm-mpath.c 2004-05-23 02:30:07.597489058 -0700
@@ -17,6 +17,7 @@
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/workqueue.h>
+#include <linux/completion.h>
#include <asm/atomic.h>
/* Path properties */
@@ -27,27 +28,36 @@ struct path {
struct priority_group *pg;
};
+inline struct block_device *dm_path_to_bdev(struct path *path)
+{
+ return path->dev->bdev;
+}
+
struct priority_group {
struct list_head list;
struct multipath *m;
- struct path_selector *ps;
+ struct path_selector ps;
unsigned nr_paths;
struct list_head paths;
};
+#define ps_to_pg(__ps) container_of((__ps), struct priority_group, ps)
+
/* Multipath context */
struct multipath {
struct list_head list;
struct dm_target *ti;
+ spinlock_t lock;
+
unsigned nr_priority_groups;
struct list_head priority_groups;
+ int initializing_pg;
+ struct completion init_pg_wait;
struct priority_group *current_pg;
- spinlock_t lock;
-
struct work_struct dispatch_failed;
struct bio_list failed_ios;
@@ -94,13 +104,7 @@ static struct priority_group *alloc_prio
if (!pg)
return NULL;
- pg->ps = kmalloc(sizeof(*pg->ps), GFP_KERNEL);
- if (!pg->ps) {
- kfree(pg);
- return NULL;
- }
- memset(pg->ps, 0, sizeof(*pg->ps));
-
+ memset(pg, 0, sizeof(*pg));
INIT_LIST_HEAD(&pg->paths);
return pg;
@@ -120,14 +124,11 @@ static void free_paths(struct list_head
static void free_priority_group(struct priority_group *pg,
struct dm_target *ti)
{
- struct path_selector *ps = pg->ps;
+ struct path_selector *ps = &pg->ps;
- if (ps) {
- if (ps->type) {
- ps->type->dtr(ps);
- dm_put_path_selector(ps->type);
- }
- kfree(ps);
+ if (ps->type) {
+ ps->type->dtr(ps);
+ dm_put_path_selector(ps->type);
}
free_paths(&pg->paths, ti);
@@ -142,6 +143,8 @@ static struct multipath *alloc_multipath
if (m) {
memset(m, 0, sizeof(*m));
INIT_LIST_HEAD(&m->priority_groups);
+ init_completion(&m->init_pg_wait);
+ m->initializing_pg = 0;
m->lock = SPIN_LOCK_UNLOCKED;
INIT_WORK(&m->dispatch_failed, dispatch_failed_ios, m);
INIT_WORK(&m->trigger_event, trigger_event, m);
@@ -169,45 +172,115 @@ static void free_multipath(struct multip
kfree(m);
}
-/*-----------------------------------------------------------------
- * The multipath daemon is responsible for resubmitting failed ios.
- *---------------------------------------------------------------*/
-static struct path *select_path(struct multipath *m, struct bio *bio,
- union map_info *info)
+static void __ps_init_complete(struct multipath *m,
+ struct priority_group *pg)
+{
+ m->initializing_pg = 0;
+ m->current_pg = pg;
+ complete_all(&m->init_pg_wait);
+ schedule_work(&m->dispatch_failed);
+}
+
+void dm_ps_init_complete(struct path_selector *ps)
{
- struct priority_group *pg;
- struct path *path = NULL;
unsigned long flags;
+ struct priority_group *pg = ps_to_pg(ps);
+ struct multipath *m = pg->m;
spin_lock_irqsave(&m->lock, flags);
+ __ps_init_complete(m, pg);
+ spin_unlock_irqrestore(&m->lock, flags);
+}
- pg = m->current_pg;
- if (pg && (path = pg->ps->type->select_path(pg->ps, bio, info)))
- goto done;
+EXPORT_SYMBOL(dm_ps_init_complete);
+
+static int select_group(struct multipath *m, struct mpath_io *mpio,
+ struct bio *bio)
+{
+ struct priority_group *pg = NULL;
+ int err;
+
+ m->current_pg = NULL;
+ m->initializing_pg = 1;
+ init_completion(&m->init_pg_wait);
- /*
- * loop through the priority groups until we
- * find a valid path.
- */
list_for_each_entry (pg, &m->priority_groups, list) {
- path = pg->ps->type->select_path(pg->ps, bio, info);
- if (path) {
- m->current_pg = pg;
- break;
+
+ if (pg->ps.type->init) {
+ spin_unlock_irq(&m->lock);
+ err = pg->ps.type->init(&pg->ps);
+ spin_lock_irq(&m->lock);
+
+ if (err == DM_PS_INITIALIZING)
+ return DM_PS_INITIALIZING;
+ else if (err == DM_PS_FAILED)
+ continue;
}
+
+ mpio->path = pg->ps.type->select_path(&pg->ps, bio,
+ &mpio->info);
+ if (mpio->path)
+ break;
}
- done:
- spin_unlock_irqrestore(&m->lock, flags);
+ __ps_init_complete(m, mpio->path ? pg : NULL);
+ return mpio->path ? DM_PS_SUCCESS : DM_PS_FAILED;
+}
+
+static int select_path1(struct multipath *m, struct mpath_io *mpio,
+ struct bio *bio, int wait)
+{
+ mpio->path = NULL;
- return path;
+ retest:
+ /*
+ * completion event, current_pg, initializing_pg and
+ * in the case of wait=0 adding to the failed_ios list for
+ * resubmission are protected under the m->lock to avoid races.
+ */
+ if (unlikely(m->initializing_pg)) {
+ if (!wait)
+ return -EWOULDBLOCK;
+
+ spin_unlock_irq(&m->lock);
+ wait_for_completion(&m->init_pg_wait);
+ spin_lock_irq(&m->lock);
+ goto retest;
+ }
+
+ if (m->current_pg) {
+ struct path_selector *ps = &m->current_pg->ps;
+
+ mpio->path = ps->type->select_path(ps, bio, &mpio->info);
+ if (!mpio->path &&
+ (select_group(m, mpio, bio) == DM_PS_INITIALIZING))
+ /*
+ * while the lock was dropped the
+ * initialization might have completed.
+ */
+ goto retest;
+ }
+
+ return mpio->path ? 0 : -EIO;
}
-static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio)
+static int map_io(struct multipath *m, struct mpath_io *mpio,
+ struct bio *bio, int wait)
{
- mpio->path = select_path(m, bio, &mpio->info);
- if (unlikely(!mpio->path))
- return -EIO;
+ int err;
+
+ spin_lock_irq(&m->lock);
+ err = select_path1(m, mpio, bio, wait);
+ if (err == -EWOULDBLOCK)
+ /*
+ * when the ps init is completed it will
+ * remap and submit this bio
+ */
+ bio_list_add(&m->failed_ios, bio);
+ spin_unlock_irq(&m->lock);
+
+ if (err)
+ return err;
bio->bi_bdev = mpio->path->dev->bdev;
return 0;
@@ -225,9 +298,29 @@ static void dispatch_failed_ios(void *da
spin_unlock_irqrestore(&m->lock, flags);
while (bio) {
+ int err;
+ struct mpath_io *mpio;
+ union map_info *info;
+
next = bio->bi_next;
bio->bi_next = NULL;
- generic_make_request(bio);
+
+ info = dm_get_mapinfo(bio);
+ mpio = info->ptr;
+
+ /*
+ * For -EWOULDBLOCK the bio could not be mapped
+ * due to a ps initialization. The bio has been
+ * requeued, and the work will be processed when
+ * the initialization is completed.
+ */
+ err = map_io(m, mpio, bio, 0);
+ if (!err)
+ generic_make_request(bio);
+ else if (err != -EWOULDBLOCK)
+ /* no paths left */
+ bio_endio(bio, bio->bi_size, -EIO);
+
bio = next;
}
}
@@ -359,13 +452,12 @@ static struct priority_group *parse_prio
goto bad;
}
- r = pst->ctr(pg->ps);
+ r = pst->ctr(&pg->ps);
if (r) {
- /* FIXME: need to put the pst ? fix after
- * factoring out the register */
+ dm_put_path_selector(pst);
goto bad;
}
- pg->ps->type = pst;
+ pg->ps.type = pst;
/*
* read the paths
@@ -389,7 +481,7 @@ static struct priority_group *parse_prio
path_args.argc = nr_params;
path_args.argv = as->argv;
- path = parse_path(&path_args, pg->ps, ti);
+ path = parse_path(&path_args, &pg->ps, ti);
if (!path)
goto bad;
@@ -461,42 +553,45 @@ static int multipath_map(struct dm_targe
union map_info *info)
{
int r;
- struct mpath_io *io;
+ struct mpath_io *mpio;
struct multipath *m = (struct multipath *) ti->private;
- io = mempool_alloc(m->mpio_pool, GFP_NOIO);
- dm_bio_record(&io->details, bio);
+ mpio = mempool_alloc(m->mpio_pool, GFP_NOIO);
+ dm_bio_record(&mpio->details, bio);
bio->bi_rw |= (1 << BIO_RW_FAILFAST);
- r = map_io(m, bio, io);
+ r = map_io(m, mpio, bio, 1);
if (unlikely(r)) {
- mempool_free(io, m->mpio_pool);
+ mempool_free(mpio, m->mpio_pool);
return r;
}
- info->ptr = io;
+ info->ptr = mpio;
return 1;
}
static int do_end_io(struct multipath *m, struct bio *bio,
- int error, struct mpath_io *io)
+ int error, struct mpath_io *mpio)
{
- struct path_selector *ps = io->path->pg->ps;
+ struct path_selector *ps = &mpio->path->pg->ps;
- error = ps->type->end_io(ps, bio, error, &io->info);
+ ps->type->end_io(ps, bio, error, &mpio->info);
if (error) {
- /* remap */
- dm_bio_restore(&io->details, bio);
- if (map_io(m, bio, io))
- /* no paths left */
- return -EIO;
- /* queue for the daemon to resubmit */
+ dm_bio_restore(&mpio->details, bio);
+
+ /* queue for the daemon to resubmit or fail */
spin_lock(&m->lock);
bio_list_add(&m->failed_ios, bio);
+ /*
+ * If a ps is initializing we do not queue the work
+ * becuase when the ps initialization has completed
+ * it will queue the dispatch function to be run.
+ */
+ if (!m->initializing_pg)
+ schedule_work(&m->dispatch_failed);
spin_unlock(&m->lock);
- schedule_work(&m->dispatch_failed);
return 1; /* io not complete */
}
@@ -510,7 +605,18 @@ static int multipath_end_io(struct dm_ta
struct mpath_io *io = (struct mpath_io *) info->ptr;
int r;
- r = do_end_io(m, bio, error, io);
+ /*
+ * If we report to dm that we are going to retry the
+ * bio, but that fails due to a pst->init failure
+ * calling bio_endio from dm-mpath.c will end up
+ * calling dm-mpath's endio fn, so this test catches
+ * that case.
+ */
+ if (io->path)
+ r = do_end_io(m, bio, error, io);
+ else
+ r = -EIO;
+
if (r <= 0)
mempool_free(io, m->mpio_pool);
@@ -541,12 +647,12 @@ static int multipath_status(struct dm_ta
EMIT("%u ", m->nr_priority_groups);
list_for_each_entry(pg, &m->priority_groups, list) {
- EMIT("%u %u ", pg->nr_paths, pg->ps->type->info_args);
+ EMIT("%u %u ", pg->nr_paths, pg->ps.type->info_args);
list_for_each_entry(p, &pg->paths, list) {
format_dev_t(buffer, p->dev->bdev->bd_dev);
EMIT("%s ", buffer);
- sz += pg->ps->type->status(pg->ps, p, type,
+ sz += pg->ps.type->status(&pg->ps, p, type,
result + sz, maxlen - sz);
}
}
@@ -556,13 +662,13 @@ static int multipath_status(struct dm_ta
EMIT("%u ", m->nr_priority_groups);
list_for_each_entry(pg, &m->priority_groups, list) {
- EMIT("%s %u %u ", pg->ps->type->name,
- pg->nr_paths, pg->ps->type->table_args);
+ EMIT("%s %u %u ", pg->ps.type->name,
+ pg->nr_paths, pg->ps.type->table_args);
list_for_each_entry(p, &pg->paths, list) {
format_dev_t(buffer, p->dev->bdev->bd_dev);
EMIT("%s ", buffer);
- sz += pg->ps->type->status(pg->ps, p, type,
+ sz += pg->ps.type->status(&pg->ps, p, type,
result + sz, maxlen - sz);
}
diff -aurp linux-2.6.6/drivers/md/dm-path-selector.c linux-2.6.6-work/drivers/md/dm-path-selector.c
--- linux-2.6.6/drivers/md/dm-path-selector.c 2004-05-23 02:29:58.826618626 -0700
+++ linux-2.6.6-work/drivers/md/dm-path-selector.c 2004-05-23 02:30:07.626485324 -0700
@@ -254,15 +254,15 @@ static int rr_add_path(struct path_selec
return 0;
}
-static int rr_end_io(struct path_selector *ps, struct bio *bio, int error,
- union map_info *info)
+static void rr_end_io(struct path_selector *ps, struct bio *bio, int error,
+ union map_info *info)
{
unsigned long flags;
struct selector *s = (struct selector *) ps->context;
struct path_info *pi = (struct path_info *)info->ptr;
if (likely(!error))
- return 0;
+ return;
spin_lock_irqsave(&s->lock, flags);
@@ -274,8 +274,6 @@ static int rr_end_io(struct path_selecto
}
spin_unlock_irqrestore(&s->lock, flags);
-
- return -EIO;
}
/* Path selector */
diff -aurp linux-2.6.6/drivers/md/dm-path-selector.h linux-2.6.6-work/drivers/md/dm-path-selector.h
--- linux-2.6.6/drivers/md/dm-path-selector.h 2004-05-23 02:29:58.828618369 -0700
+++ linux-2.6.6-work/drivers/md/dm-path-selector.h 2004-05-23 02:30:07.657481332 -0700
@@ -16,6 +16,8 @@
struct path;
+struct block_device *dm_path_to_bdev(struct path *path);
+
/*
* We provide an abstraction for the code that chooses which path
* to send some io down.
@@ -33,6 +35,22 @@ typedef int (*ps_ctr_fn) (struct path_se
typedef void (*ps_dtr_fn) (struct path_selector *ps);
/*
+ * Allows the ps to initialize itself. It should return one
+ * of the following return values. iif DM_PS_INITIALIZING is
+ * returned the path-selector must call dm_ps_init_complete
+ * when the initializtion has completed.
+ */
+enum {
+ DM_PS_SUCCESS,
+ DM_PS_FAILED,
+ DM_PS_INITIALIZING,
+};
+
+void dm_ps_init_complete(struct path_selector *ps);
+
+typedef int (*ps_init_fn) (struct path_selector *ps);
+
+/*
* Add an opaque path object, along with some selector specific
* path args (eg, path priority).
*/
@@ -52,8 +70,8 @@ typedef int (*ps_add_path_fn) (struct pa
typedef struct path *(*ps_select_path_fn) (struct path_selector *ps,
struct bio *bio,
union map_info *info);
-typedef int (*ps_end_io) (struct path_selector *ps, struct bio *bio,
- int error, union map_info *info);
+typedef void (*ps_end_io) (struct path_selector *ps, struct bio *bio,
+ int error, union map_info *info);
/*
* Table content based on parameters added in ps_add_path_fn
@@ -73,6 +91,7 @@ struct path_selector_type {
unsigned int info_args;
ps_ctr_fn ctr;
ps_dtr_fn dtr;
+ ps_init_fn init;
ps_add_path_fn add_path;
ps_select_path_fn select_path;
diff -aurp linux-2.6.6/include/linux/device-mapper.h linux-2.6.6-work/include/linux/device-mapper.h
--- linux-2.6.6/include/linux/device-mapper.h 2004-05-09 19:32:53.000000000 -0700
+++ linux-2.6.6-work/include/linux/device-mapper.h 2004-05-23 02:30:07.000000000 -0700
@@ -18,6 +18,8 @@ union map_info {
unsigned long long ll;
};
+inline union map_info *dm_get_mapinfo(struct bio *bio);
+
/*
* In the constructor the target parameter will already have the
* table, type, begin and len fields filled in.
