X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fmd%2Fdm-mpath.c;fp=drivers%2Fmd%2Fdm-mpath.c;h=3aa0135069672d8fe7f3ed4c6e743d969478c95f;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=cf70a0dc8bd1c20aae215150494ae87f023c1134;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index cf70a0dc8..3aa013506 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -21,6 +21,7 @@
 #include <linux/workqueue.h>
 #include <asm/atomic.h>
 
+#define DM_MSG_PREFIX "multipath"
 #define MESG_STR(x) x, sizeof(x)
 
 /* Path properties */
@@ -30,7 +31,7 @@ struct pgpath {
 	struct priority_group *pg;	/* Owning PG */
 	unsigned fail_count;		/* Cumulative failure count */
 
-	struct path path;
+	struct dm_path path;
 };
 
 #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
@@ -100,11 +101,11 @@ typedef int (*action_fn) (struct pgpath *pgpath);
 
 #define MIN_IOS 256	/* Mempool size */
 
-static kmem_cache_t *_mpio_cache;
+static struct kmem_cache *_mpio_cache;
 
 struct workqueue_struct *kmultipathd;
-static void process_queued_ios(void *data);
-static void trigger_event(void *data);
+static void process_queued_ios(struct work_struct *work);
+static void trigger_event(struct work_struct *work);
 
 
 /*-----------------------------------------------
@@ -113,12 +114,10 @@ static void trigger_event(void *data);
 
 static struct pgpath *alloc_pgpath(void)
 {
-	struct pgpath *pgpath = kmalloc(sizeof(*pgpath), GFP_KERNEL);
+	struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
 
-	if (pgpath) {
-		memset(pgpath, 0, sizeof(*pgpath));
+	if (pgpath)
 		pgpath->path.is_active = 1;
-	}
 
 	return pgpath;
 }
@@ -132,12 +131,10 @@ static struct priority_group *alloc_priority_group(void)
 {
 	struct priority_group *pg;
 
-	pg = kmalloc(sizeof(*pg), GFP_KERNEL);
-	if (!pg)
-		return NULL;
+	pg = kzalloc(sizeof(*pg), GFP_KERNEL);
 
-	memset(pg, 0, sizeof(*pg));
-	INIT_LIST_HEAD(&pg->pgpaths);
+	if (pg)
+		INIT_LIST_HEAD(&pg->pgpaths);
 
 	return pg;
 }
@@ -167,24 +164,24 @@ static void free_priority_group(struct priority_group *pg,
 	kfree(pg);
 }
 
-static struct multipath *alloc_multipath(void)
+static struct multipath *alloc_multipath(struct dm_target *ti)
 {
 	struct multipath *m;
 
-	m = kmalloc(sizeof(*m), GFP_KERNEL);
+	m = kzalloc(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);
+		INIT_WORK(&m->process_queued_ios, process_queued_ios);
+		INIT_WORK(&m->trigger_event, trigger_event);
+		m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
 		if (!m->mpio_pool) {
 			kfree(m);
 			return NULL;
 		}
+		m->ti = ti;
+		ti->private = m;
 	}
 
 	return m;
@@ -232,7 +229,7 @@ static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
 
 static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg)
 {
-	struct path *path;
+	struct dm_path *path;
 
 	path = pg->ps.type->select_path(&pg->ps, &m->repeat_count);
 	if (!path)
@@ -285,10 +282,27 @@ failed:
 	m->current_pg = NULL;
 }
 
+/*
+ * Check whether bios must be queued in the device-mapper core rather
+ * than here in the target.
+ *
+ * m->lock must be held on entry.
+ *
+ * If m->queue_if_no_path and m->saved_queue_if_no_path hold the
+ * same value then we are not between multipath_presuspend()
+ * and multipath_resume() calls and we have no need to check
+ * for the DMF_NOFLUSH_SUSPENDING flag.
+ */
+static int __must_push_back(struct multipath *m)
+{
+	return (m->queue_if_no_path != m->saved_queue_if_no_path &&
+		dm_noflush_suspending(m->ti));
+}
+
 static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
 		  unsigned was_queued)
 {
-	int r = 1;
+	int r = DM_MAPIO_REMAPPED;
 	unsigned long flags;
 	struct pgpath *pgpath;
 
@@ -313,11 +327,13 @@ static int map_io(struct multipath *m, struct bio *bio, struct mpath_io *mpio,
 		    !m->queue_io)
 			queue_work(kmultipathd, &m->process_queued_ios);
 		pgpath = NULL;
-		r = 0;
-	} else if (!pgpath)
-		r = -EIO;		/* Failed */
-	else
+		r = DM_MAPIO_SUBMITTED;
+	} else if (pgpath)
 		bio->bi_bdev = pgpath->path.dev->bdev;
+	else if (__must_push_back(m))
+		r = DM_MAPIO_REQUEUE;
+	else
+		r = -EIO;	/* Failed */
 
 	mpio->pgpath = pgpath;
 
@@ -375,16 +391,19 @@ static void dispatch_queued_ios(struct multipath *m)
 		r = map_io(m, bio, mpio, 1);
 		if (r < 0)
 			bio_endio(bio, bio->bi_size, r);
-		else if (r == 1)
+		else if (r == DM_MAPIO_REMAPPED)
 			generic_make_request(bio);
+		else if (r == DM_MAPIO_REQUEUE)
+			bio_endio(bio, bio->bi_size, -EIO);
 
 		bio = next;
 	}
 }
 
-static void process_queued_ios(void *data)
+static void process_queued_ios(struct work_struct *work)
 {
-	struct multipath *m = (struct multipath *) data;
+	struct multipath *m =
+		container_of(work, struct multipath, process_queued_ios);
 	struct hw_handler *hwh = &m->hw_handler;
 	struct pgpath *pgpath = NULL;
 	unsigned init_required = 0, must_queue = 1;
@@ -424,9 +443,10 @@ out:
  * An event is triggered whenever a path is taken out of use.
  * Includes path failure and PG bypass.
  */
-static void trigger_event(void *data)
+static void trigger_event(struct work_struct *work)
 {
-	struct multipath *m = (struct multipath *) data;
+	struct multipath *m =
+		container_of(work, struct multipath, trigger_event);
 
 	dm_table_event(m->ti->table);
 }
@@ -447,8 +467,6 @@ struct param {
 	char *error;
 };
 
-#define ESTR(s) ("dm-multipath: " s)
-
 static int read_param(struct param *param, char *str, unsigned *v, char **error)
 {
 	if (!str ||
@@ -496,12 +514,12 @@ static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
 	unsigned ps_argc;
 
 	static struct param _params[] = {
-		{0, 1024, ESTR("invalid number of path selector args")},
+		{0, 1024, "invalid number of path selector args"},
 	};
 
 	pst = dm_get_path_selector(shift(as));
 	if (!pst) {
-		ti->error = ESTR("unknown path selector type");
+		ti->error = "unknown path selector type";
 		return -EINVAL;
 	}
 
@@ -512,7 +530,7 @@ static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
 	r = pst->create(&pg->ps, ps_argc, as->argv);
 	if (r) {
 		dm_put_path_selector(pst);
-		ti->error = ESTR("path selector constructor failed");
+		ti->error = "path selector constructor failed";
 		return r;
 	}
 
@@ -530,7 +548,7 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
 
 	/* we need at least a path arg */
 	if (as->argc < 1) {
-		ti->error = ESTR("no device given");
+		ti->error = "no device given";
 		return NULL;
 	}
 
@@ -541,7 +559,7 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
 	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");
+		ti->error = "error getting device";
 		goto bad;
 	}
 
@@ -559,27 +577,27 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
 }
 
 static struct priority_group *parse_priority_group(struct arg_set *as,
-						   struct multipath *m,
-						   struct dm_target *ti)
+						   struct multipath *m)
 {
 	static struct param _params[] = {
-		{1, 1024, ESTR("invalid number of paths")},
-		{0, 1024, ESTR("invalid number of selector args")}
+		{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 = ESTR("not enough priority group aruments");
+		ti->error = "not enough priority group aruments";
 		return NULL;
 	}
 
 	pg = alloc_priority_group();
 	if (!pg) {
-		ti->error = ESTR("couldn't allocate priority group");
+		ti->error = "couldn't allocate priority group";
 		return NULL;
 	}
 	pg->m = m;
@@ -626,15 +644,15 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
 	return NULL;
 }
 
-static int parse_hw_handler(struct arg_set *as, struct multipath *m,
-			    struct dm_target *ti)
+static int parse_hw_handler(struct arg_set *as, struct multipath *m)
 {
 	int r;
 	struct hw_handler_type *hwht;
 	unsigned hw_argc;
+	struct dm_target *ti = m->ti;
 
 	static struct param _params[] = {
-		{0, 1024, ESTR("invalid number of hardware handler args")},
+		{0, 1024, "invalid number of hardware handler args"},
 	};
 
 	r = read_param(_params, shift(as), &hw_argc, &ti->error);
@@ -646,14 +664,14 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m,
 
 	hwht = dm_get_hw_handler(shift(as));
 	if (!hwht) {
-		ti->error = ESTR("unknown hardware handler type");
+		ti->error = "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");
+		ti->error = "hardware handler constructor failed";
 		return r;
 	}
 
@@ -663,14 +681,14 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m,
 	return 0;
 }
 
-static int parse_features(struct arg_set *as, struct multipath *m,
-			  struct dm_target *ti)
+static int parse_features(struct arg_set *as, struct multipath *m)
 {
 	int r;
 	unsigned argc;
+	struct dm_target *ti = m->ti;
 
 	static struct param _params[] = {
-		{0, 1, ESTR("invalid number of feature args")},
+		{0, 1, "invalid number of feature args"},
 	};
 
 	r = read_param(_params, shift(as), &argc, &ti->error);
@@ -693,8 +711,8 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 {
 	/* target parameters */
 	static struct param _params[] = {
-		{1, 1024, ESTR("invalid number of priority groups")},
-		{1, 1024, ESTR("invalid initial priority group number")},
+		{1, 1024, "invalid number of priority groups"},
+		{1, 1024, "invalid initial priority group number"},
 	};
 
 	int r;
@@ -706,19 +724,17 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 	as.argc = argc;
 	as.argv = argv;
 
-	m = alloc_multipath();
+	m = alloc_multipath(ti);
 	if (!m) {
-		ti->error = ESTR("can't allocate multipath");
+		ti->error = "can't allocate multipath";
 		return -EINVAL;
 	}
 
-	m->ti = ti;
-
-	r = parse_features(&as, m, ti);
+	r = parse_features(&as, m);
 	if (r)
 		goto bad;
 
-	r = parse_hw_handler(&as, m, ti);
+	r = parse_hw_handler(&as, m);
 	if (r)
 		goto bad;
 
@@ -734,7 +750,7 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 	while (as.argc) {
 		struct priority_group *pg;
 
-		pg = parse_priority_group(&as, m, ti);
+		pg = parse_priority_group(&as, m);
 		if (!pg) {
 			r = -EINVAL;
 			goto bad;
@@ -749,13 +765,11 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
 	}
 
 	if (pg_count != m->nr_priority_groups) {
-		ti->error = ESTR("priority group count mismatch");
+		ti->error = "priority group count mismatch";
 		r = -EINVAL;
 		goto bad;
 	}
 
-	ti->private = m;
-
 	return 0;
 
  bad:
@@ -790,7 +804,7 @@ static int multipath_map(struct dm_target *ti, struct bio *bio,
 	map_context->ptr = mpio;
 	bio->bi_rw |= (1 << BIO_RW_FAILFAST);
 	r = map_io(m, bio, mpio, 0);
-	if (r < 0)
+	if (r < 0 || r == DM_MAPIO_REQUEUE)
 		mempool_free(mpio, m->mpio_pool);
 
 	return r;
@@ -809,7 +823,7 @@ static int fail_path(struct pgpath *pgpath)
 	if (!pgpath->path.is_active)
 		goto out;
 
-	DMWARN("dm-multipath: Failing path %s.", pgpath->path.dev->name);
+	DMWARN("Failing path %s.", pgpath->path.dev->name);
 
 	pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
 	pgpath->path.is_active = 0;
@@ -964,7 +978,7 @@ static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
 /*
  * pg_init must call this when it has completed its initialisation
  */
-void dm_pg_init_complete(struct path *path, unsigned err_flags)
+void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
 {
 	struct pgpath *pgpath = path_to_pgpath(path);
 	struct priority_group *pg = pgpath->pg;
@@ -1014,7 +1028,10 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 
 	spin_lock_irqsave(&m->lock, flags);
 	if (!m->nr_valid_paths) {
-		if (!m->queue_if_no_path) {
+		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 {
@@ -1049,7 +1066,7 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 		queue_work(kmultipathd, &m->process_queued_ios);
 	spin_unlock_irqrestore(&m->lock, flags);
 
-	return 1;	/* io not complete */
+	return DM_ENDIO_INCOMPLETE;	/* io not complete */
 }
 
 static int multipath_end_io(struct dm_target *ti, struct bio *bio,
@@ -1067,7 +1084,7 @@ static int multipath_end_io(struct dm_target *ti, struct bio *bio,
 		if (ps->type->end_io)
 			ps->type->end_io(ps, &pgpath->path);
 	}
-	if (r <= 0)
+	if (r != DM_ENDIO_INCOMPLETE)
 		mempool_free(mpio, m->mpio_pool);
 
 	return r;
@@ -1252,7 +1269,7 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
 	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",
+		DMWARN("message: error getting device %s",
 		       argv[1]);
 		return -EINVAL;
 	}
@@ -1268,12 +1285,47 @@ error:
 	return -EINVAL;
 }
 
+static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
+			   struct file *filp, unsigned int cmd,
+			   unsigned long arg)
+{
+	struct multipath *m = (struct multipath *) ti->private;
+	struct block_device *bdev = NULL;
+	unsigned long flags;
+	struct file fake_file = {};
+	struct dentry fake_dentry = {};
+	int r = 0;
+
+	fake_file.f_path.dentry = &fake_dentry;
+
+	spin_lock_irqsave(&m->lock, flags);
+
+	if (!m->current_pgpath)
+		__choose_pgpath(m);
+
+	if (m->current_pgpath) {
+		bdev = m->current_pgpath->path.dev->bdev;
+		fake_dentry.d_inode = bdev->bd_inode;
+		fake_file.f_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->bd_inode, &fake_file,
+					 bdev->bd_disk, cmd, arg);
+}
+
 /*-----------------------------------------------------------------
  * Module setup
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
 	.name = "multipath",
-	.version = {1, 0, 4},
+	.version = {1, 0, 5},
 	.module = THIS_MODULE,
 	.ctr = multipath_ctr,
 	.dtr = multipath_dtr,
@@ -1283,6 +1335,7 @@ static struct target_type multipath_target = {
 	.resume = multipath_resume,
 	.status = multipath_status,
 	.message = multipath_message,
+	.ioctl  = multipath_ioctl,
 };
 
 static int __init dm_multipath_init(void)
@@ -1311,7 +1364,7 @@ static int __init dm_multipath_init(void)
 		return -ENOMEM;
 	}
 
-	DMINFO("dm-multipath version %u.%u.%u loaded",
+	DMINFO("version %u.%u.%u loaded",
 	       multipath_target.version[0], multipath_target.version[1],
 	       multipath_target.version[2]);