1 files changed, 178 insertions, 85 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 53875ae73ad4..c37433d3cd82 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -142,6 +142,7 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
 	unsigned long limit;
 	unsigned long last_waited = 0;
 	int force_reg = 0;
+	int sync_pending = 0;
 	struct blk_plug plug;
 
 	/*
@@ -229,6 +230,22 @@ loop_lock:
 
 		BUG_ON(atomic_read(&cur->bi_cnt) == 0);
 
+		/*
+		 * if we're doing the sync list, record that our
+		 * plug has some sync requests on it
+		 *
+		 * If we're doing the regular list and there are
+		 * sync requests sitting around, unplug before
+		 * we add more
+		 */
+		if (pending_bios == &device->pending_sync_bios) {
+			sync_pending = 1;
+		} else if (sync_pending) {
+			blk_finish_plug(&plug);
+			blk_start_plug(&plug);
+			sync_pending = 0;
+		}
+
 		submit_bio(cur->bi_rw, cur);
 		num_run++;
 		batch_run++;
@@ -349,6 +366,14 @@ static noinline int device_list_add(const char *path,
 		}
 		INIT_LIST_HEAD(&device->dev_alloc_list);
 
+		/* init readahead state */
+		spin_lock_init(&device->reada_lock);
+		device->reada_curr_zone = NULL;
+		atomic_set(&device->reada_in_flight, 0);
+		device->reada_next = 0;
+		INIT_RADIX_TREE(&device->reada_zones, GFP_NOFS & ~__GFP_WAIT);
+		INIT_RADIX_TREE(&device->reada_extents, GFP_NOFS & ~__GFP_WAIT);
+
 		mutex_lock(&fs_devices->device_list_mutex);
 		list_add_rcu(&device->dev_list, &fs_devices->devices);
 		mutex_unlock(&fs_devices->device_list_mutex);
@@ -500,6 +525,9 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 			fs_devices->rw_devices--;
 		}
 
+		if (device->can_discard)
+			fs_devices->num_can_discard--;
+
 		new_device = kmalloc(sizeof(*new_device), GFP_NOFS);
 		BUG_ON(!new_device);
 		memcpy(new_device, device, sizeof(*new_device));
@@ -508,6 +536,7 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 		new_device->bdev = NULL;
 		new_device->writeable = 0;
 		new_device->in_fs_metadata = 0;
+		new_device->can_discard = 0;
 		list_replace_rcu(&device->dev_list, &new_device->dev_list);
 
 		call_rcu(&device->rcu, free_device);
@@ -547,6 +576,7 @@ int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 				fmode_t flags, void *holder)
 {
+	struct request_queue *q;
 	struct block_device *bdev;
 	struct list_head *head = &fs_devices->devices;
 	struct btrfs_device *device;
@@ -575,10 +605,8 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 		set_blocksize(bdev, 4096);
 
 		bh = btrfs_read_dev_super(bdev);
-		if (!bh) {
-			ret = -EINVAL;
+		if (!bh)
 			goto error_close;
-		}
 
 		disk_super = (struct btrfs_super_block *)bh->b_data;
 		devid = btrfs_stack_device_id(&disk_super->dev_item);
@@ -603,6 +631,12 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 			seeding = 0;
 		}
 
+		q = bdev_get_queue(bdev);
+		if (blk_queue_discard(q)) {
+			device->can_discard = 1;
+			fs_devices->num_can_discard++;
+		}
+
 		device->bdev = bdev;
 		device->in_fs_metadata = 0;
 		device->mode = flags;
@@ -627,7 +661,7 @@ error:
 		continue;
 	}
 	if (fs_devices->open_devices == 0) {
-		ret = -EIO;
+		ret = -EINVAL;
 		goto out;
 	}
 	fs_devices->seeding = seeding;
@@ -835,6 +869,7 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans,
 
 	max_hole_start = search_start;
 	max_hole_size = 0;
+	hole_size = 0;
 
 	if (search_start >= search_end) {
 		ret = -ENOSPC;
@@ -917,7 +952,14 @@ next:
 		cond_resched();
 	}
 
-	hole_size = search_end- search_start;
+	/*
+	 * At this point, search_start should be the end of
+	 * allocated dev extents, and when shrinking the device,
+	 * search_end may be smaller than search_start.
+	 */
+	if (search_end > search_start)
+		hole_size = search_end - search_start;
+
 	if (hole_size > max_hole_size) {
 		max_hole_start = search_start;
 		max_hole_size = hole_size;
@@ -957,7 +999,7 @@ static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 	key.objectid = device->devid;
 	key.offset = start;
 	key.type = BTRFS_DEV_EXTENT_KEY;
-
+again:
 	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 	if (ret > 0) {
 		ret = btrfs_previous_item(root, path, key.objectid,
@@ -970,6 +1012,9 @@ static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 					struct btrfs_dev_extent);
 		BUG_ON(found_key.offset > start || found_key.offset +
 		       btrfs_dev_extent_length(leaf, extent) < start);
+		key = found_key;
+		btrfs_release_path(path);
+		goto again;
 	} else if (ret == 0) {
 		leaf = path->nodes[0];
 		extent = btrfs_item_ptr(leaf, path->slots[0],
@@ -977,8 +1022,13 @@ static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 	}
 	BUG_ON(ret);
 
-	if (device->bytes_used > 0)
-		device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
+	if (device->bytes_used > 0) {
+		u64 len = btrfs_dev_extent_length(leaf, extent);
+		device->bytes_used -= len;
+		spin_lock(&root->fs_info->free_chunk_lock);
+		root->fs_info->free_chunk_space += len;
+		spin_unlock(&root->fs_info->free_chunk_lock);
+	}
 	ret = btrfs_del_item(trans, root, path);
 
 out:
@@ -1320,6 +1370,11 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 	if (ret)
 		goto error_undo;
 
+	spin_lock(&root->fs_info->free_chunk_lock);
+	root->fs_info->free_chunk_space = device->total_bytes -
+		device->bytes_used;
+	spin_unlock(&root->fs_info->free_chunk_lock);
+
 	device->in_fs_metadata = 0;
 	btrfs_scrub_cancel_dev(root, device);
 
@@ -1351,8 +1406,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 	call_rcu(&device->rcu, free_device);
 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
-	num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
-	btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
+	num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
+	btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
 
 	if (cur_devices->open_devices == 0) {
 		struct btrfs_fs_devices *fs_devices;
@@ -1414,7 +1469,7 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 	struct btrfs_fs_devices *old_devices;
 	struct btrfs_fs_devices *seed_devices;
-	struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
+	struct btrfs_super_block *disk_super = root->fs_info->super_copy;
 	struct btrfs_device *device;
 	u64 super_flags;
 
@@ -1543,6 +1598,7 @@ error:
 
 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 {
+	struct request_queue *q;
 	struct btrfs_trans_handle *trans;
 	struct btrfs_device *device;
 	struct block_device *bdev;
@@ -1612,6 +1668,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
 	lock_chunks(root);
 
+	q = bdev_get_queue(bdev);
+	if (blk_queue_discard(q))
+		device->can_discard = 1;
 	device->writeable = 1;
 	device->work.func = pending_bios_fn;
 	generate_random_uuid(device->uuid);
@@ -1647,17 +1706,23 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 	root->fs_info->fs_devices->num_devices++;
 	root->fs_info->fs_devices->open_devices++;
 	root->fs_info->fs_devices->rw_devices++;
+	if (device->can_discard)
+		root->fs_info->fs_devices->num_can_discard++;
 	root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
 
+	spin_lock(&root->fs_info->free_chunk_lock);
+	root->fs_info->free_chunk_space += device->total_bytes;
+	spin_unlock(&root->fs_info->free_chunk_lock);
+
 	if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 		root->fs_info->fs_devices->rotating = 1;
 
-	total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
-	btrfs_set_super_total_bytes(&root->fs_info->super_copy,
+	total_bytes = btrfs_super_total_bytes(root->fs_info->super_copy);
+	btrfs_set_super_total_bytes(root->fs_info->super_copy,
 				    total_bytes + device->total_bytes);
 
-	total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
-	btrfs_set_super_num_devices(&root->fs_info->super_copy,
+	total_bytes = btrfs_super_num_devices(root->fs_info->super_copy);
+	btrfs_set_super_num_devices(root->fs_info->super_copy,
 				    total_bytes + 1);
 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
@@ -1748,7 +1813,7 @@ static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
 		      struct btrfs_device *device, u64 new_size)
 {
 	struct btrfs_super_block *super_copy =
-		&device->dev_root->fs_info->super_copy;
+		device->dev_root->fs_info->super_copy;
 	u64 old_total = btrfs_super_total_bytes(super_copy);
 	u64 diff = new_size - device->total_bytes;
 
@@ -1807,7 +1872,7 @@ static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
 			chunk_offset)
 {
-	struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+	struct btrfs_super_block *super_copy = root->fs_info->super_copy;
 	struct btrfs_disk_key *disk_key;
 	struct btrfs_chunk *chunk;
 	u8 *ptr;
@@ -2133,7 +2198,7 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 	bool retried = false;
 	struct extent_buffer *l;
 	struct btrfs_key key;
-	struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+	struct btrfs_super_block *super_copy = root->fs_info->super_copy;
 	u64 old_total = btrfs_super_total_bytes(super_copy);
 	u64 old_size = device->total_bytes;
 	u64 diff = device->total_bytes - new_size;
@@ -2150,8 +2215,12 @@ int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
 	lock_chunks(root);
 
 	device->total_bytes = new_size;
-	if (device->writeable)
+	if (device->writeable) {
 		device->fs_devices->total_rw_bytes -= diff;
+		spin_lock(&root->fs_info->free_chunk_lock);
+		root->fs_info->free_chunk_space -= diff;
+		spin_unlock(&root->fs_info->free_chunk_lock);
+	}
 	unlock_chunks(root);
 
 again:
@@ -2215,6 +2284,9 @@ again:
 		device->total_bytes = old_size;
 		if (device->writeable)
 			device->fs_devices->total_rw_bytes += diff;
+		spin_lock(&root->fs_info->free_chunk_lock);
+		root->fs_info->free_chunk_space += diff;
+		spin_unlock(&root->fs_info->free_chunk_lock);
 		unlock_chunks(root);
 		goto done;
 	}
@@ -2250,7 +2322,7 @@ static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
 			   struct btrfs_key *key,
 			   struct btrfs_chunk *chunk, int item_size)
 {
-	struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+	struct btrfs_super_block *super_copy = root->fs_info->super_copy;
 	struct btrfs_disk_key disk_key;
 	u32 array_size;
 	u8 *ptr;
@@ -2413,9 +2485,10 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 			total_avail = device->total_bytes - device->bytes_used;
 		else
 			total_avail = 0;
-		/* avail is off by max(alloc_start, 1MB), but that is the same
-		 * for all devices, so it doesn't hurt the sorting later on
-		 */
+
+		/* If there is no space on this device, skip it. */
+		if (total_avail == 0)
+			continue;
 
 		ret = find_free_dev_extent(trans, device,
 					   max_stripe_size * dev_stripes,
@@ -2572,6 +2645,11 @@ static int __finish_chunk_alloc(struct btrfs_trans_handle *trans,
 		index++;
 	}
 
+	spin_lock(&extent_root->fs_info->free_chunk_lock);
+	extent_root->fs_info->free_chunk_space -= (stripe_size *
+						   map->num_stripes);
+	spin_unlock(&extent_root->fs_info->free_chunk_lock);
+
 	index = 0;
 	stripe = &chunk->stripe;
 	while (index < map->num_stripes) {
@@ -2805,7 +2883,7 @@ static int find_live_mirror(struct map_lookup *map, int first, int num,
 
 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 			     u64 logical, u64 *length,
-			     struct btrfs_multi_bio **multi_ret,
+			     struct btrfs_bio **bbio_ret,
 			     int mirror_num)
 {
 	struct extent_map *em;
@@ -2823,18 +2901,18 @@ static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 	int i;
 	int num_stripes;
 	int max_errors = 0;
-	struct btrfs_multi_bio *multi = NULL;
+	struct btrfs_bio *bbio = NULL;
 
-	if (multi_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
+	if (bbio_ret && !(rw & (REQ_WRITE | REQ_DISCARD)))
 		stripes_allocated = 1;
 again:
-	if (multi_ret) {
-		multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
+	if (bbio_ret) {
+		bbio = kzalloc(btrfs_bio_size(stripes_allocated),
 				GFP_NOFS);
-		if (!multi)
+		if (!bbio)
 			return -ENOMEM;
 
-		atomic_set(&multi->error, 0);
+		atomic_set(&bbio->error, 0);
 	}
 
 	read_lock(&em_tree->lock);
@@ -2855,7 +2933,7 @@ again:
 	if (mirror_num > map->num_stripes)
 		mirror_num = 0;
 
-	/* if our multi bio struct is too small, back off and try again */
+	/* if our btrfs_bio struct is too small, back off and try again */
 	if (rw & REQ_WRITE) {
 		if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
 				 BTRFS_BLOCK_GROUP_DUP)) {
@@ -2874,11 +2952,11 @@ again:
 			stripes_required = map->num_stripes;
 		}
 	}
-	if (multi_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
+	if (bbio_ret && (rw & (REQ_WRITE | REQ_DISCARD)) &&
 	    stripes_allocated < stripes_required) {
 		stripes_allocated = map->num_stripes;
 		free_extent_map(em);
-		kfree(multi);
+		kfree(bbio);
 		goto again;
 	}
 	stripe_nr = offset;
@@ -2907,7 +2985,7 @@ again:
 		*length = em->len - offset;
 	}
 
-	if (!multi_ret)
+	if (!bbio_ret)
 		goto out;
 
 	num_stripes = 1;
@@ -2932,13 +3010,17 @@ again:
 			stripe_index = find_live_mirror(map, 0,
 					    map->num_stripes,
 					    current->pid % map->num_stripes);
+			mirror_num = stripe_index + 1;
 		}
 
 	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
-		if (rw & (REQ_WRITE | REQ_DISCARD))
+		if (rw & (REQ_WRITE | REQ_DISCARD)) {
 			num_stripes = map->num_stripes;
-		else if (mirror_num)
+		} else if (mirror_num) {
 			stripe_index = mirror_num - 1;
+		} else {
+			mirror_num = 1;
+		}
 
 	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 		int factor = map->num_stripes / map->sub_stripes;
@@ -2958,6 +3040,7 @@ again:
 			stripe_index = find_live_mirror(map, stripe_index,
 					      map->sub_stripes, stripe_index +
 					      current->pid % map->sub_stripes);
+			mirror_num = stripe_index + 1;
 		}
 	} else {
 		/*
@@ -2966,15 +3049,16 @@ again:
 		 * stripe_index is the number of our device in the stripe array
 		 */
 		stripe_index = do_div(stripe_nr, map->num_stripes);
+		mirror_num = stripe_index + 1;
 	}
 	BUG_ON(stripe_index >= map->num_stripes);
 
 	if (rw & REQ_DISCARD) {
 		for (i = 0; i < num_stripes; i++) {
-			multi->stripes[i].physical =
+			bbio->stripes[i].physical =
 				map->stripes[stripe_index].physical +
 				stripe_offset + stripe_nr * map->stripe_len;
-			multi->stripes[i].dev = map->stripes[stripe_index].dev;
+			bbio->stripes[i].dev = map->stripes[stripe_index].dev;
 
 			if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
 				u64 stripes;
@@ -2995,16 +3079,16 @@ again:
 				}
 				stripes = stripe_nr_end - 1 - j;
 				do_div(stripes, map->num_stripes);
-				multi->stripes[i].length = map->stripe_len *
+				bbio->stripes[i].length = map->stripe_len *
 					(stripes - stripe_nr + 1);
 
 				if (i == 0) {
-					multi->stripes[i].length -=
+					bbio->stripes[i].length -=
 						stripe_offset;
 					stripe_offset = 0;
 				}
 				if (stripe_index == last_stripe)
-					multi->stripes[i].length -=
+					bbio->stripes[i].length -=
 						stripe_end_offset;
 			} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 				u64 stripes;
@@ -3029,11 +3113,11 @@ again:
 				}
 				stripes = stripe_nr_end - 1 - j;
 				do_div(stripes, factor);
-				multi->stripes[i].length = map->stripe_len *
+				bbio->stripes[i].length = map->stripe_len *
 					(stripes - stripe_nr + 1);
 
 				if (i < map->sub_stripes) {
-					multi->stripes[i].length -=
+					bbio->stripes[i].length -=
 						stripe_offset;
 					if (i == map->sub_stripes - 1)
 						stripe_offset = 0;
@@ -3041,11 +3125,11 @@ again:
 				if (stripe_index >= last_stripe &&
 				    stripe_index <= (last_stripe +
 						     map->sub_stripes - 1)) {
-					multi->stripes[i].length -=
+					bbio->stripes[i].length -=
 						stripe_end_offset;
 				}
 			} else
-				multi->stripes[i].length = *length;
+				bbio->stripes[i].length = *length;
 
 			stripe_index++;
 			if (stripe_index == map->num_stripes) {
@@ -3056,19 +3140,20 @@ again:
 		}
 	} else {
 		for (i = 0; i < num_stripes; i++) {
-			multi->stripes[i].physical =
+			bbio->stripes[i].physical =
 				map->stripes[stripe_index].physical +
 				stripe_offset +
 				stripe_nr * map->stripe_len;
-			multi->stripes[i].dev =
+			bbio->stripes[i].dev =
 				map->stripes[stripe_index].dev;
 			stripe_index++;
 		}
 	}
-	if (multi_ret) {
-		*multi_ret = multi;
-		multi->num_stripes = num_stripes;
-		multi->max_errors = max_errors;
+	if (bbio_ret) {
+		*bbio_ret = bbio;
+		bbio->num_stripes = num_stripes;
+		bbio->max_errors = max_errors;
+		bbio->mirror_num = mirror_num;
 	}
 out:
 	free_extent_map(em);
@@ -3077,9 +3162,9 @@ out:
 
 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 		      u64 logical, u64 *length,
-		      struct btrfs_multi_bio **multi_ret, int mirror_num)
+		      struct btrfs_bio **bbio_ret, int mirror_num)
 {
-	return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
+	return __btrfs_map_block(map_tree, rw, logical, length, bbio_ret,
 				 mirror_num);
 }
 
@@ -3148,28 +3233,30 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
 	return 0;
 }
 
-static void end_bio_multi_stripe(struct bio *bio, int err)
+static void btrfs_end_bio(struct bio *bio, int err)
 {
-	struct btrfs_multi_bio *multi = bio->bi_private;
+	struct btrfs_bio *bbio = bio->bi_private;
 	int is_orig_bio = 0;
 
 	if (err)
-		atomic_inc(&multi->error);
+		atomic_inc(&bbio->error);
 
-	if (bio == multi->orig_bio)
+	if (bio == bbio->orig_bio)
 		is_orig_bio = 1;
 
-	if (atomic_dec_and_test(&multi->stripes_pending)) {
+	if (atomic_dec_and_test(&bbio->stripes_pending)) {
 		if (!is_orig_bio) {
 			bio_put(bio);
-			bio = multi->orig_bio;
+			bio = bbio->orig_bio;
 		}
-		bio->bi_private = multi->private;
-		bio->bi_end_io = multi->end_io;
+		bio->bi_private = bbio->private;
+		bio->bi_end_io = bbio->end_io;
+		bio->bi_bdev = (struct block_device *)
+					(unsigned long)bbio->mirror_num;
 		/* only send an error to the higher layers if it is
 		 * beyond the tolerance of the multi-bio
 		 */
-		if (atomic_read(&multi->error) > multi->max_errors) {
+		if (atomic_read(&bbio->error) > bbio->max_errors) {
 			err = -EIO;
 		} else if (err) {
 			/*
@@ -3179,7 +3266,7 @@ static void end_bio_multi_stripe(struct bio *bio, int err)
 			set_bit(BIO_UPTODATE, &bio->bi_flags);
 			err = 0;
 		}
-		kfree(multi);
+		kfree(bbio);
 
 		bio_endio(bio, err);
 	} else if (!is_orig_bio) {
@@ -3259,20 +3346,20 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 	u64 logical = (u64)bio->bi_sector << 9;
 	u64 length = 0;
 	u64 map_length;
-	struct btrfs_multi_bio *multi = NULL;
 	int ret;
 	int dev_nr = 0;
 	int total_devs = 1;
+	struct btrfs_bio *bbio = NULL;
 
 	length = bio->bi_size;
 	map_tree = &root->fs_info->mapping_tree;
 	map_length = length;
 
-	ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
+	ret = btrfs_map_block(map_tree, rw, logical, &map_length, &bbio,
 			      mirror_num);
 	BUG_ON(ret);
 
-	total_devs = multi->num_stripes;
+	total_devs = bbio->num_stripes;
 	if (map_length < length) {
 		printk(KERN_CRIT "mapping failed logical %llu bio len %llu "
 		       "len %llu\n", (unsigned long long)logical,
@@ -3280,25 +3367,28 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 		       (unsigned long long)map_length);
 		BUG();
 	}
-	multi->end_io = first_bio->bi_end_io;
-	multi->private = first_bio->bi_private;
-	multi->orig_bio = first_bio;
-	atomic_set(&multi->stripes_pending, multi->num_stripes);
+
+	bbio->orig_bio = first_bio;
+	bbio->private = first_bio->bi_private;
+	bbio->end_io = first_bio->bi_end_io;
+	atomic_set(&bbio->stripes_pending, bbio->num_stripes);
 
 	while (dev_nr < total_devs) {
-		if (total_devs > 1) {
-			if (dev_nr < total_devs - 1) {
-				bio = bio_clone(first_bio, GFP_NOFS);
-				BUG_ON(!bio);
-			} else {
-				bio = first_bio;
-			}
-			bio->bi_private = multi;
-			bio->bi_end_io = end_bio_multi_stripe;
+		if (dev_nr < total_devs - 1) {
+			bio = bio_clone(first_bio, GFP_NOFS);
+			BUG_ON(!bio);
+		} else {
+			bio = first_bio;
 		}
-		bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
-		dev = multi->stripes[dev_nr].dev;
+		bio->bi_private = bbio;
+		bio->bi_end_io = btrfs_end_bio;
+		bio->bi_sector = bbio->stripes[dev_nr].physical >> 9;
+		dev = bbio->stripes[dev_nr].dev;
 		if (dev && dev->bdev && (rw != WRITE || dev->writeable)) {
+			pr_debug("btrfs_map_bio: rw %d, secor=%llu, dev=%lu "
+				 "(%s id %llu), size=%u\n", rw,
+				 (u64)bio->bi_sector, (u_long)dev->bdev->bd_dev,
+				 dev->name, dev->devid, bio->bi_size);
 			bio->bi_bdev = dev->bdev;
 			if (async_submit)
 				schedule_bio(root, dev, rw, bio);
@@ -3311,8 +3401,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
 		}
 		dev_nr++;
 	}
-	if (total_devs == 1)
-		kfree(multi);
 	return 0;
 }
 
@@ -3573,15 +3661,20 @@ static int read_one_dev(struct btrfs_root *root,
 	fill_device_from_item(leaf, dev_item, device);
 	device->dev_root = root->fs_info->dev_root;
 	device->in_fs_metadata = 1;
-	if (device->writeable)
+	if (device->writeable) {
 		device->fs_devices->total_rw_bytes += device->total_bytes;
+		spin_lock(&root->fs_info->free_chunk_lock);
+		root->fs_info->free_chunk_space += device->total_bytes -
+			device->bytes_used;
+		spin_unlock(&root->fs_info->free_chunk_lock);
+	}
 	ret = 0;
 	return ret;
 }
 
 int btrfs_read_sys_array(struct btrfs_root *root)
 {
-	struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
+	struct btrfs_super_block *super_copy = root->fs_info->super_copy;
 	struct extent_buffer *sb;
 	struct btrfs_disk_key *disk_key;
 	struct btrfs_chunk *chunk;