1 files changed, 564 insertions, 370 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f627674b37db..4c32497311d2 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -41,6 +41,17 @@
 					 BTRFS_BLOCK_GROUP_RAID10 | \
 					 BTRFS_BLOCK_GROUP_RAID56_MASK)
 
+struct btrfs_io_geometry {
+	u32 stripe_index;
+	u32 stripe_nr;
+	int mirror_num;
+	int num_stripes;
+	u64 stripe_offset;
+	u64 raid56_full_stripe_start;
+	int max_errors;
+	enum btrfs_map_op op;
+};
+
 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
 	[BTRFS_RAID_RAID10] = {
 		.sub_stripes	= 2,
@@ -1742,19 +1753,18 @@ out:
 
 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
 {
-	struct extent_map_tree *em_tree;
-	struct extent_map *em;
 	struct rb_node *n;
 	u64 ret = 0;
 
-	em_tree = &fs_info->mapping_tree;
-	read_lock(&em_tree->lock);
-	n = rb_last(&em_tree->map.rb_root);
+	read_lock(&fs_info->mapping_tree_lock);
+	n = rb_last(&fs_info->mapping_tree.rb_root);
 	if (n) {
-		em = rb_entry(n, struct extent_map, rb_node);
-		ret = em->start + em->len;
+		struct btrfs_chunk_map *map;
+
+		map = rb_entry(n, struct btrfs_chunk_map, rb_node);
+		ret = map->start + map->chunk_len;
 	}
-	read_unlock(&em_tree->lock);
+	read_unlock(&fs_info->mapping_tree_lock);
 
 	return ret;
 }
@@ -2986,6 +2996,81 @@ static int btrfs_del_sys_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 	return ret;
 }
 
+struct btrfs_chunk_map *btrfs_find_chunk_map_nolock(struct btrfs_fs_info *fs_info,
+						    u64 logical, u64 length)
+{
+	struct rb_node *node = fs_info->mapping_tree.rb_root.rb_node;
+	struct rb_node *prev = NULL;
+	struct rb_node *orig_prev;
+	struct btrfs_chunk_map *map;
+	struct btrfs_chunk_map *prev_map = NULL;
+
+	while (node) {
+		map = rb_entry(node, struct btrfs_chunk_map, rb_node);
+		prev = node;
+		prev_map = map;
+
+		if (logical < map->start) {
+			node = node->rb_left;
+		} else if (logical >= map->start + map->chunk_len) {
+			node = node->rb_right;
+		} else {
+			refcount_inc(&map->refs);
+			return map;
+		}
+	}
+
+	if (!prev)
+		return NULL;
+
+	orig_prev = prev;
+	while (prev && logical >= prev_map->start + prev_map->chunk_len) {
+		prev = rb_next(prev);
+		prev_map = rb_entry(prev, struct btrfs_chunk_map, rb_node);
+	}
+
+	if (!prev) {
+		prev = orig_prev;
+		prev_map = rb_entry(prev, struct btrfs_chunk_map, rb_node);
+		while (prev && logical < prev_map->start) {
+			prev = rb_prev(prev);
+			prev_map = rb_entry(prev, struct btrfs_chunk_map, rb_node);
+		}
+	}
+
+	if (prev) {
+		u64 end = logical + length;
+
+		/*
+		 * Caller can pass a U64_MAX length when it wants to get any
+		 * chunk starting at an offset of 'logical' or higher, so deal
+		 * with underflow by resetting the end offset to U64_MAX.
+		 */
+		if (end < logical)
+			end = U64_MAX;
+
+		if (end > prev_map->start &&
+		    logical < prev_map->start + prev_map->chunk_len) {
+			refcount_inc(&prev_map->refs);
+			return prev_map;
+		}
+	}
+
+	return NULL;
+}
+
+struct btrfs_chunk_map *btrfs_find_chunk_map(struct btrfs_fs_info *fs_info,
+					     u64 logical, u64 length)
+{
+	struct btrfs_chunk_map *map;
+
+	read_lock(&fs_info->mapping_tree_lock);
+	map = btrfs_find_chunk_map_nolock(fs_info, logical, length);
+	read_unlock(&fs_info->mapping_tree_lock);
+
+	return map;
+}
+
 /*
  * Find the mapping containing the given logical extent.
  *
@@ -2994,38 +3079,37 @@ static int btrfs_del_sys_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
  *
  * Return: Chunk mapping or ERR_PTR.
  */
-struct extent_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
-				       u64 logical, u64 length)
+struct btrfs_chunk_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
+					    u64 logical, u64 length)
 {
-	struct extent_map_tree *em_tree;
-	struct extent_map *em;
+	struct btrfs_chunk_map *map;
 
-	em_tree = &fs_info->mapping_tree;
-	read_lock(&em_tree->lock);
-	em = lookup_extent_mapping(em_tree, logical, length);
-	read_unlock(&em_tree->lock);
+	map = btrfs_find_chunk_map(fs_info, logical, length);
 
-	if (!em) {
+	if (unlikely(!map)) {
+		read_unlock(&fs_info->mapping_tree_lock);
 		btrfs_crit(fs_info,
 			   "unable to find chunk map for logical %llu length %llu",
 			   logical, length);
 		return ERR_PTR(-EINVAL);
 	}
 
-	if (em->start > logical || em->start + em->len <= logical) {
+	if (unlikely(map->start > logical || map->start + map->chunk_len <= logical)) {
+		read_unlock(&fs_info->mapping_tree_lock);
 		btrfs_crit(fs_info,
 			   "found a bad chunk map, wanted %llu-%llu, found %llu-%llu",
-			   logical, logical + length, em->start, em->start + em->len);
-		free_extent_map(em);
+			   logical, logical + length, map->start,
+			   map->start + map->chunk_len);
+		btrfs_free_chunk_map(map);
 		return ERR_PTR(-EINVAL);
 	}
 
-	/* callers are responsible for dropping em's ref. */
-	return em;
+	/* Callers are responsible for dropping the reference. */
+	return map;
 }
 
 static int remove_chunk_item(struct btrfs_trans_handle *trans,
-			     struct map_lookup *map, u64 chunk_offset)
+			     struct btrfs_chunk_map *map, u64 chunk_offset)
 {
 	int i;
 
@@ -3050,23 +3134,21 @@ static int remove_chunk_item(struct btrfs_trans_handle *trans,
 int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	u64 dev_extent_len = 0;
 	int i, ret = 0;
 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 
-	em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
-	if (IS_ERR(em)) {
+	map = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
+	if (IS_ERR(map)) {
 		/*
 		 * This is a logic error, but we don't want to just rely on the
 		 * user having built with ASSERT enabled, so if ASSERT doesn't
 		 * do anything we still error out.
 		 */
 		ASSERT(0);
-		return PTR_ERR(em);
+		return PTR_ERR(map);
 	}
-	map = em->map_lookup;
 
 	/*
 	 * First delete the device extent items from the devices btree.
@@ -3169,7 +3251,7 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
 		goto out;
 	}
 
-	trace_btrfs_chunk_free(fs_info, map, chunk_offset, em->len);
+	trace_btrfs_chunk_free(fs_info, map, chunk_offset, map->chunk_len);
 
 	if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
 		ret = btrfs_del_sys_chunk(fs_info, chunk_offset);
@@ -3188,7 +3270,7 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
 	 */
 	btrfs_trans_release_chunk_metadata(trans);
 
-	ret = btrfs_remove_block_group(trans, chunk_offset, em);
+	ret = btrfs_remove_block_group(trans, map);
 	if (ret) {
 		btrfs_abort_transaction(trans, ret);
 		goto out;
@@ -3200,7 +3282,7 @@ out:
 		trans->removing_chunk = false;
 	}
 	/* once for us */
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ret;
 }
 
@@ -5347,24 +5429,131 @@ static int decide_stripe_size(struct btrfs_fs_devices *fs_devices,
 	}
 }
 
+static void chunk_map_device_set_bits(struct btrfs_chunk_map *map, unsigned int bits)
+{
+	for (int i = 0; i < map->num_stripes; i++) {
+		struct btrfs_io_stripe *stripe = &map->stripes[i];
+		struct btrfs_device *device = stripe->dev;
+
+		set_extent_bit(&device->alloc_state, stripe->physical,
+			       stripe->physical + map->stripe_size - 1,
+			       bits | EXTENT_NOWAIT, NULL);
+	}
+}
+
+static void chunk_map_device_clear_bits(struct btrfs_chunk_map *map, unsigned int bits)
+{
+	for (int i = 0; i < map->num_stripes; i++) {
+		struct btrfs_io_stripe *stripe = &map->stripes[i];
+		struct btrfs_device *device = stripe->dev;
+
+		__clear_extent_bit(&device->alloc_state, stripe->physical,
+				   stripe->physical + map->stripe_size - 1,
+				   bits | EXTENT_NOWAIT,
+				   NULL, NULL);
+	}
+}
+
+void btrfs_remove_chunk_map(struct btrfs_fs_info *fs_info, struct btrfs_chunk_map *map)
+{
+	write_lock(&fs_info->mapping_tree_lock);
+	rb_erase_cached(&map->rb_node, &fs_info->mapping_tree);
+	RB_CLEAR_NODE(&map->rb_node);
+	chunk_map_device_clear_bits(map, CHUNK_ALLOCATED);
+	write_unlock(&fs_info->mapping_tree_lock);
+
+	/* Once for the tree reference. */
+	btrfs_free_chunk_map(map);
+}
+
+EXPORT_FOR_TESTS
+int btrfs_add_chunk_map(struct btrfs_fs_info *fs_info, struct btrfs_chunk_map *map)
+{
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	bool leftmost = true;
+
+	write_lock(&fs_info->mapping_tree_lock);
+	p = &fs_info->mapping_tree.rb_root.rb_node;
+	while (*p) {
+		struct btrfs_chunk_map *entry;
+
+		parent = *p;
+		entry = rb_entry(parent, struct btrfs_chunk_map, rb_node);
+
+		if (map->start < entry->start) {
+			p = &(*p)->rb_left;
+		} else if (map->start > entry->start) {
+			p = &(*p)->rb_right;
+			leftmost = false;
+		} else {
+			write_unlock(&fs_info->mapping_tree_lock);
+			return -EEXIST;
+		}
+	}
+	rb_link_node(&map->rb_node, parent, p);
+	rb_insert_color_cached(&map->rb_node, &fs_info->mapping_tree, leftmost);
+	chunk_map_device_set_bits(map, CHUNK_ALLOCATED);
+	chunk_map_device_clear_bits(map, CHUNK_TRIMMED);
+	write_unlock(&fs_info->mapping_tree_lock);
+
+	return 0;
+}
+
+EXPORT_FOR_TESTS
+struct btrfs_chunk_map *btrfs_alloc_chunk_map(int num_stripes, gfp_t gfp)
+{
+	struct btrfs_chunk_map *map;
+
+	map = kmalloc(btrfs_chunk_map_size(num_stripes), gfp);
+	if (!map)
+		return NULL;
+
+	refcount_set(&map->refs, 1);
+	RB_CLEAR_NODE(&map->rb_node);
+
+	return map;
+}
+
+struct btrfs_chunk_map *btrfs_clone_chunk_map(struct btrfs_chunk_map *map, gfp_t gfp)
+{
+	const int size = btrfs_chunk_map_size(map->num_stripes);
+	struct btrfs_chunk_map *clone;
+
+	clone = kmemdup(map, size, gfp);
+	if (!clone)
+		return NULL;
+
+	refcount_set(&clone->refs, 1);
+	RB_CLEAR_NODE(&clone->rb_node);
+
+	return clone;
+}
+
 static struct btrfs_block_group *create_chunk(struct btrfs_trans_handle *trans,
 			struct alloc_chunk_ctl *ctl,
 			struct btrfs_device_info *devices_info)
 {
 	struct btrfs_fs_info *info = trans->fs_info;
-	struct map_lookup *map = NULL;
-	struct extent_map_tree *em_tree;
+	struct btrfs_chunk_map *map;
 	struct btrfs_block_group *block_group;
-	struct extent_map *em;
 	u64 start = ctl->start;
 	u64 type = ctl->type;
 	int ret;
 	int i;
 	int j;
 
-	map = kmalloc(map_lookup_size(ctl->num_stripes), GFP_NOFS);
+	map = btrfs_alloc_chunk_map(ctl->num_stripes, GFP_NOFS);
 	if (!map)
 		return ERR_PTR(-ENOMEM);
+
+	map->start = start;
+	map->chunk_len = ctl->chunk_size;
+	map->stripe_size = ctl->stripe_size;
+	map->type = type;
+	map->io_align = BTRFS_STRIPE_LEN;
+	map->io_width = BTRFS_STRIPE_LEN;
+	map->sub_stripes = ctl->sub_stripes;
 	map->num_stripes = ctl->num_stripes;
 
 	for (i = 0; i < ctl->ndevs; ++i) {
@@ -5375,41 +5564,22 @@ static struct btrfs_block_group *create_chunk(struct btrfs_trans_handle *trans,
 						   j * ctl->stripe_size;
 		}
 	}
-	map->io_align = BTRFS_STRIPE_LEN;
-	map->io_width = BTRFS_STRIPE_LEN;
-	map->type = type;
-	map->sub_stripes = ctl->sub_stripes;
 
 	trace_btrfs_chunk_alloc(info, map, start, ctl->chunk_size);
 
-	em = alloc_extent_map();
-	if (!em) {
-		kfree(map);
-		return ERR_PTR(-ENOMEM);
-	}
-	set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
-	em->map_lookup = map;
-	em->start = start;
-	em->len = ctl->chunk_size;
-	em->block_start = 0;
-	em->block_len = em->len;
-	em->orig_block_len = ctl->stripe_size;
-
-	em_tree = &info->mapping_tree;
-	write_lock(&em_tree->lock);
-	ret = add_extent_mapping(em_tree, em, 0);
+	ret = btrfs_add_chunk_map(info, map);
 	if (ret) {
-		write_unlock(&em_tree->lock);
-		free_extent_map(em);
+		btrfs_free_chunk_map(map);
 		return ERR_PTR(ret);
 	}
-	write_unlock(&em_tree->lock);
 
 	block_group = btrfs_make_block_group(trans, type, start, ctl->chunk_size);
-	if (IS_ERR(block_group))
-		goto error_del_extent;
+	if (IS_ERR(block_group)) {
+		btrfs_remove_chunk_map(info, map);
+		return block_group;
+	}
 
-	for (i = 0; i < map->num_stripes; i++) {
+	for (int i = 0; i < map->num_stripes; i++) {
 		struct btrfs_device *dev = map->stripes[i].dev;
 
 		btrfs_device_set_bytes_used(dev,
@@ -5422,23 +5592,10 @@ static struct btrfs_block_group *create_chunk(struct btrfs_trans_handle *trans,
 	atomic64_sub(ctl->stripe_size * map->num_stripes,
 		     &info->free_chunk_space);
 
-	free_extent_map(em);
 	check_raid56_incompat_flag(info, type);
 	check_raid1c34_incompat_flag(info, type);
 
 	return block_group;
-
-error_del_extent:
-	write_lock(&em_tree->lock);
-	remove_extent_mapping(em_tree, em);
-	write_unlock(&em_tree->lock);
-
-	/* One for our allocation */
-	free_extent_map(em);
-	/* One for the tree reference */
-	free_extent_map(em);
-
-	return block_group;
 }
 
 struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans,
@@ -5514,8 +5671,7 @@ int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
 	struct btrfs_key key;
 	struct btrfs_chunk *chunk;
 	struct btrfs_stripe *stripe;
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	size_t item_size;
 	int i;
 	int ret;
@@ -5544,14 +5700,13 @@ int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
 	 */
 	lockdep_assert_held(&fs_info->chunk_mutex);
 
-	em = btrfs_get_chunk_map(fs_info, bg->start, bg->length);
-	if (IS_ERR(em)) {
-		ret = PTR_ERR(em);
+	map = btrfs_get_chunk_map(fs_info, bg->start, bg->length);
+	if (IS_ERR(map)) {
+		ret = PTR_ERR(map);
 		btrfs_abort_transaction(trans, ret);
 		return ret;
 	}
 
-	map = em->map_lookup;
 	item_size = btrfs_chunk_item_size(map->num_stripes);
 
 	chunk = kzalloc(item_size, GFP_NOFS);
@@ -5608,7 +5763,7 @@ int btrfs_chunk_alloc_add_chunk_item(struct btrfs_trans_handle *trans,
 
 out:
 	kfree(chunk);
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ret;
 }
 
@@ -5653,7 +5808,7 @@ static noinline int init_first_rw_device(struct btrfs_trans_handle *trans)
 	return 0;
 }
 
-static inline int btrfs_chunk_max_errors(struct map_lookup *map)
+static inline int btrfs_chunk_max_errors(struct btrfs_chunk_map *map)
 {
 	const int index = btrfs_bg_flags_to_raid_index(map->type);
 
@@ -5662,17 +5817,15 @@ static inline int btrfs_chunk_max_errors(struct map_lookup *map)
 
 bool btrfs_chunk_writeable(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 {
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	int miss_ndevs = 0;
 	int i;
 	bool ret = true;
 
-	em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
-	if (IS_ERR(em))
+	map = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
+	if (IS_ERR(map))
 		return false;
 
-	map = em->map_lookup;
 	for (i = 0; i < map->num_stripes; i++) {
 		if (test_bit(BTRFS_DEV_STATE_MISSING,
 					&map->stripes[i].dev->dev_state)) {
@@ -5693,38 +5846,37 @@ bool btrfs_chunk_writeable(struct btrfs_fs_info *fs_info, u64 chunk_offset)
 	if (miss_ndevs > btrfs_chunk_max_errors(map))
 		ret = false;
 end:
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ret;
 }
 
-void btrfs_mapping_tree_free(struct extent_map_tree *tree)
+void btrfs_mapping_tree_free(struct btrfs_fs_info *fs_info)
 {
-	struct extent_map *em;
+	write_lock(&fs_info->mapping_tree_lock);
+	while (!RB_EMPTY_ROOT(&fs_info->mapping_tree.rb_root)) {
+		struct btrfs_chunk_map *map;
+		struct rb_node *node;
 
-	while (1) {
-		write_lock(&tree->lock);
-		em = lookup_extent_mapping(tree, 0, (u64)-1);
-		if (em)
-			remove_extent_mapping(tree, em);
-		write_unlock(&tree->lock);
-		if (!em)
-			break;
-		/* once for us */
-		free_extent_map(em);
-		/* once for the tree */
-		free_extent_map(em);
+		node = rb_first_cached(&fs_info->mapping_tree);
+		map = rb_entry(node, struct btrfs_chunk_map, rb_node);
+		rb_erase_cached(&map->rb_node, &fs_info->mapping_tree);
+		RB_CLEAR_NODE(&map->rb_node);
+		chunk_map_device_clear_bits(map, CHUNK_ALLOCATED);
+		/* Once for the tree ref. */
+		btrfs_free_chunk_map(map);
+		cond_resched_rwlock_write(&fs_info->mapping_tree_lock);
 	}
+	write_unlock(&fs_info->mapping_tree_lock);
 }
 
 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 {
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	enum btrfs_raid_types index;
 	int ret = 1;
 
-	em = btrfs_get_chunk_map(fs_info, logical, len);
-	if (IS_ERR(em))
+	map = btrfs_get_chunk_map(fs_info, logical, len);
+	if (IS_ERR(map))
 		/*
 		 * We could return errors for these cases, but that could get
 		 * ugly and we'd probably do the same thing which is just not do
@@ -5733,7 +5885,6 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 		 */
 		return 1;
 
-	map = em->map_lookup;
 	index = btrfs_bg_flags_to_raid_index(map->type);
 
 	/* Non-RAID56, use their ncopies from btrfs_raid_array. */
@@ -5750,53 +5901,49 @@ int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 		 * stripe under reconstruction.
 		 */
 		ret = map->num_stripes;
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ret;
 }
 
 unsigned long btrfs_full_stripe_len(struct btrfs_fs_info *fs_info,
 				    u64 logical)
 {
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	unsigned long len = fs_info->sectorsize;
 
 	if (!btrfs_fs_incompat(fs_info, RAID56))
 		return len;
 
-	em = btrfs_get_chunk_map(fs_info, logical, len);
+	map = btrfs_get_chunk_map(fs_info, logical, len);
 
-	if (!WARN_ON(IS_ERR(em))) {
-		map = em->map_lookup;
+	if (!WARN_ON(IS_ERR(map))) {
 		if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
 			len = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
-		free_extent_map(em);
+		btrfs_free_chunk_map(map);
 	}
 	return len;
 }
 
 int btrfs_is_parity_mirror(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
 {
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	int ret = 0;
 
 	if (!btrfs_fs_incompat(fs_info, RAID56))
 		return 0;
 
-	em = btrfs_get_chunk_map(fs_info, logical, len);
+	map = btrfs_get_chunk_map(fs_info, logical, len);
 
-	if(!WARN_ON(IS_ERR(em))) {
-		map = em->map_lookup;
+	if (!WARN_ON(IS_ERR(map))) {
 		if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
 			ret = 1;
-		free_extent_map(em);
+		btrfs_free_chunk_map(map);
 	}
 	return ret;
 }
 
 static int find_live_mirror(struct btrfs_fs_info *fs_info,
-			    struct map_lookup *map, int first,
+			    struct btrfs_chunk_map *map, int first,
 			    int dev_replace_is_ongoing)
 {
 	int i;
@@ -5903,8 +6050,7 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 					       u64 logical, u64 *length_ret,
 					       u32 *num_stripes)
 {
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	struct btrfs_discard_stripe *stripes;
 	u64 length = *length_ret;
 	u64 offset;
@@ -5922,11 +6068,9 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 	int ret;
 	int i;
 
-	em = btrfs_get_chunk_map(fs_info, logical, length);
-	if (IS_ERR(em))
-		return ERR_CAST(em);
-
-	map = em->map_lookup;
+	map = btrfs_get_chunk_map(fs_info, logical, length);
+	if (IS_ERR(map))
+		return ERR_CAST(map);
 
 	/* we don't discard raid56 yet */
 	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
@@ -5934,8 +6078,8 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 		goto out_free_map;
 	}
 
-	offset = logical - em->start;
-	length = min_t(u64, em->start + em->len - logical, length);
+	offset = logical - map->start;
+	length = min_t(u64, map->start + map->chunk_len - logical, length);
 	*length_ret = length;
 
 	/*
@@ -6032,10 +6176,10 @@ struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 		}
 	}
 
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return stripes;
 out_free_map:
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ERR_PTR(ret);
 }
 
@@ -6133,17 +6277,16 @@ static void handle_ops_on_dev_replace(enum btrfs_map_op op,
 	bioc->replace_nr_stripes = nr_extra_stripes;
 }
 
-static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
-			    u64 offset, u32 *stripe_nr, u64 *stripe_offset,
-			    u64 *full_stripe_start)
+static u64 btrfs_max_io_len(struct btrfs_chunk_map *map, u64 offset,
+			    struct btrfs_io_geometry *io_geom)
 {
 	/*
 	 * Stripe_nr is the stripe where this block falls.  stripe_offset is
 	 * the offset of this block in its stripe.
 	 */
-	*stripe_offset = offset & BTRFS_STRIPE_LEN_MASK;
-	*stripe_nr = offset >> BTRFS_STRIPE_LEN_SHIFT;
-	ASSERT(*stripe_offset < U32_MAX);
+	io_geom->stripe_offset = offset & BTRFS_STRIPE_LEN_MASK;
+	io_geom->stripe_nr = offset >> BTRFS_STRIPE_LEN_SHIFT;
+	ASSERT(io_geom->stripe_offset < U32_MAX);
 
 	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
 		unsigned long full_stripe_len =
@@ -6158,18 +6301,17 @@ static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
 		 * to go rounddown(), not round_down(), as nr_data_stripes is
 		 * not ensured to be power of 2.
 		 */
-		*full_stripe_start =
-			btrfs_stripe_nr_to_offset(
-				rounddown(*stripe_nr, nr_data_stripes(map)));
+		io_geom->raid56_full_stripe_start = btrfs_stripe_nr_to_offset(
+			rounddown(io_geom->stripe_nr, nr_data_stripes(map)));
 
-		ASSERT(*full_stripe_start + full_stripe_len > offset);
-		ASSERT(*full_stripe_start <= offset);
+		ASSERT(io_geom->raid56_full_stripe_start + full_stripe_len > offset);
+		ASSERT(io_geom->raid56_full_stripe_start <= offset);
 		/*
 		 * For writes to RAID56, allow to write a full stripe set, but
 		 * no straddling of stripe sets.
 		 */
-		if (op == BTRFS_MAP_WRITE)
-			return full_stripe_len - (offset - *full_stripe_start);
+		if (io_geom->op == BTRFS_MAP_WRITE)
+			return full_stripe_len - (offset - io_geom->raid56_full_stripe_start);
 	}
 
 	/*
@@ -6177,26 +6319,180 @@ static u64 btrfs_max_io_len(struct map_lookup *map, enum btrfs_map_op op,
 	 * a single disk).
 	 */
 	if (map->type & BTRFS_BLOCK_GROUP_STRIPE_MASK)
-		return BTRFS_STRIPE_LEN - *stripe_offset;
+		return BTRFS_STRIPE_LEN - io_geom->stripe_offset;
 	return U64_MAX;
 }
 
-static int set_io_stripe(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
-			 u64 logical, u64 *length, struct btrfs_io_stripe *dst,
-			 struct map_lookup *map, u32 stripe_index,
-			 u64 stripe_offset, u64 stripe_nr)
+static int set_io_stripe(struct btrfs_fs_info *fs_info, u64 logical,
+			 u64 *length, struct btrfs_io_stripe *dst,
+			 struct btrfs_chunk_map *map,
+			 struct btrfs_io_geometry *io_geom)
 {
-	dst->dev = map->stripes[stripe_index].dev;
+	dst->dev = map->stripes[io_geom->stripe_index].dev;
 
-	if (op == BTRFS_MAP_READ && btrfs_need_stripe_tree_update(fs_info, map->type))
+	if (io_geom->op == BTRFS_MAP_READ &&
+	    btrfs_need_stripe_tree_update(fs_info, map->type))
 		return btrfs_get_raid_extent_offset(fs_info, logical, length,
-						    map->type, stripe_index, dst);
+						    map->type,
+						    io_geom->stripe_index, dst);
 
-	dst->physical = map->stripes[stripe_index].physical +
-			stripe_offset + btrfs_stripe_nr_to_offset(stripe_nr);
+	dst->physical = map->stripes[io_geom->stripe_index].physical +
+			io_geom->stripe_offset +
+			btrfs_stripe_nr_to_offset(io_geom->stripe_nr);
 	return 0;
 }
 
+static bool is_single_device_io(struct btrfs_fs_info *fs_info,
+				const struct btrfs_io_stripe *smap,
+				const struct btrfs_chunk_map *map,
+				int num_alloc_stripes,
+				enum btrfs_map_op op, int mirror_num)
+{
+	if (!smap)
+		return false;
+
+	if (num_alloc_stripes != 1)
+		return false;
+
+	if (btrfs_need_stripe_tree_update(fs_info, map->type) && op != BTRFS_MAP_READ)
+		return false;
+
+	if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1)
+		return false;
+
+	return true;
+}
+
+static void map_blocks_raid0(const struct btrfs_chunk_map *map,
+			     struct btrfs_io_geometry *io_geom)
+{
+	io_geom->stripe_index = io_geom->stripe_nr % map->num_stripes;
+	io_geom->stripe_nr /= map->num_stripes;
+	if (io_geom->op == BTRFS_MAP_READ)
+		io_geom->mirror_num = 1;
+}
+
+static void map_blocks_raid1(struct btrfs_fs_info *fs_info,
+			     struct btrfs_chunk_map *map,
+			     struct btrfs_io_geometry *io_geom,
+			     bool dev_replace_is_ongoing)
+{
+	if (io_geom->op != BTRFS_MAP_READ) {
+		io_geom->num_stripes = map->num_stripes;
+		return;
+	}
+
+	if (io_geom->mirror_num) {
+		io_geom->stripe_index = io_geom->mirror_num - 1;
+		return;
+	}
+
+	io_geom->stripe_index = find_live_mirror(fs_info, map, 0,
+						 dev_replace_is_ongoing);
+	io_geom->mirror_num = io_geom->stripe_index + 1;
+}
+
+static void map_blocks_dup(const struct btrfs_chunk_map *map,
+			   struct btrfs_io_geometry *io_geom)
+{
+	if (io_geom->op != BTRFS_MAP_READ) {
+		io_geom->num_stripes = map->num_stripes;
+		return;
+	}
+
+	if (io_geom->mirror_num) {
+		io_geom->stripe_index = io_geom->mirror_num - 1;
+		return;
+	}
+
+	io_geom->mirror_num = 1;
+}
+
+static void map_blocks_raid10(struct btrfs_fs_info *fs_info,
+			      struct btrfs_chunk_map *map,
+			      struct btrfs_io_geometry *io_geom,
+			      bool dev_replace_is_ongoing)
+{
+	u32 factor = map->num_stripes / map->sub_stripes;
+	int old_stripe_index;
+
+	io_geom->stripe_index = (io_geom->stripe_nr % factor) * map->sub_stripes;
+	io_geom->stripe_nr /= factor;
+
+	if (io_geom->op != BTRFS_MAP_READ) {
+		io_geom->num_stripes = map->sub_stripes;
+		return;
+	}
+
+	if (io_geom->mirror_num) {
+		io_geom->stripe_index += io_geom->mirror_num - 1;
+		return;
+	}
+
+	old_stripe_index = io_geom->stripe_index;
+	io_geom->stripe_index = find_live_mirror(fs_info, map,
+						 io_geom->stripe_index,
+						 dev_replace_is_ongoing);
+	io_geom->mirror_num = io_geom->stripe_index - old_stripe_index + 1;
+}
+
+static void map_blocks_raid56_write(struct btrfs_chunk_map *map,
+				    struct btrfs_io_geometry *io_geom,
+				    u64 logical, u64 *length)
+{
+	int data_stripes = nr_data_stripes(map);
+
+	/*
+	 * Needs full stripe mapping.
+	 *
+	 * Push stripe_nr back to the start of the full stripe For those cases
+	 * needing a full stripe, @stripe_nr is the full stripe number.
+	 *
+	 * Originally we go raid56_full_stripe_start / full_stripe_len, but
+	 * that can be expensive.  Here we just divide @stripe_nr with
+	 * @data_stripes.
+	 */
+	io_geom->stripe_nr /= data_stripes;
+
+	/* RAID[56] write or recovery. Return all stripes */
+	io_geom->num_stripes = map->num_stripes;
+	io_geom->max_errors = btrfs_chunk_max_errors(map);
+
+	/* Return the length to the full stripe end. */
+	*length = min(logical + *length,
+		      io_geom->raid56_full_stripe_start + map->start +
+		      btrfs_stripe_nr_to_offset(data_stripes)) -
+		logical;
+	io_geom->stripe_index = 0;
+	io_geom->stripe_offset = 0;
+}
+
+static void map_blocks_raid56_read(struct btrfs_chunk_map *map,
+				   struct btrfs_io_geometry *io_geom)
+{
+	int data_stripes = nr_data_stripes(map);
+
+	ASSERT(io_geom->mirror_num <= 1);
+	/* Just grab the data stripe directly. */
+	io_geom->stripe_index = io_geom->stripe_nr % data_stripes;
+	io_geom->stripe_nr /= data_stripes;
+
+	/* We distribute the parity blocks across stripes. */
+	io_geom->stripe_index =
+		(io_geom->stripe_nr + io_geom->stripe_index) % map->num_stripes;
+
+	if (io_geom->op == BTRFS_MAP_READ && io_geom->mirror_num < 1)
+		io_geom->mirror_num = 1;
+}
+
+static void map_blocks_single(const struct btrfs_chunk_map *map,
+			      struct btrfs_io_geometry *io_geom)
+{
+	io_geom->stripe_index = io_geom->stripe_nr % map->num_stripes;
+	io_geom->stripe_nr /= map->num_stripes;
+	io_geom->mirror_num = io_geom->stripe_index + 1;
+}
+
 /*
  * Map one logical range to one or more physical ranges.
  *
@@ -6237,43 +6533,37 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 		    struct btrfs_io_context **bioc_ret,
 		    struct btrfs_io_stripe *smap, int *mirror_num_ret)
 {
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
+	struct btrfs_io_geometry io_geom = { 0 };
 	u64 map_offset;
-	u64 stripe_offset;
-	u32 stripe_nr;
-	u32 stripe_index;
-	int data_stripes;
 	int i;
 	int ret = 0;
-	int mirror_num = (mirror_num_ret ? *mirror_num_ret : 0);
-	int num_stripes;
 	int num_copies;
-	int max_errors = 0;
 	struct btrfs_io_context *bioc = NULL;
 	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
 	int dev_replace_is_ongoing = 0;
 	u16 num_alloc_stripes;
-	u64 raid56_full_stripe_start = (u64)-1;
 	u64 max_len;
 
 	ASSERT(bioc_ret);
 
+	io_geom.mirror_num = (mirror_num_ret ? *mirror_num_ret : 0);
+	io_geom.num_stripes = 1;
+	io_geom.stripe_index = 0;
+	io_geom.op = op;
+
 	num_copies = btrfs_num_copies(fs_info, logical, fs_info->sectorsize);
-	if (mirror_num > num_copies)
+	if (io_geom.mirror_num > num_copies)
 		return -EINVAL;
 
-	em = btrfs_get_chunk_map(fs_info, logical, *length);
-	if (IS_ERR(em))
-		return PTR_ERR(em);
+	map = btrfs_get_chunk_map(fs_info, logical, *length);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
 
-	map = em->map_lookup;
-	data_stripes = nr_data_stripes(map);
-
-	map_offset = logical - em->start;
-	max_len = btrfs_max_io_len(map, op, map_offset, &stripe_nr,
-				   &stripe_offset, &raid56_full_stripe_start);
-	*length = min_t(u64, em->len - map_offset, max_len);
+	map_offset = logical - map->start;
+	io_geom.raid56_full_stripe_start = (u64)-1;
+	max_len = btrfs_max_io_len(map, map_offset, &io_geom);
+	*length = min_t(u64, map->chunk_len - map_offset, max_len);
 
 	down_read(&dev_replace->rwsem);
 	dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
@@ -6284,107 +6574,46 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	if (!dev_replace_is_ongoing)
 		up_read(&dev_replace->rwsem);
 
-	num_stripes = 1;
-	stripe_index = 0;
-	if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
-		stripe_index = stripe_nr % map->num_stripes;
-		stripe_nr /= map->num_stripes;
-		if (op == BTRFS_MAP_READ)
-			mirror_num = 1;
-	} else if (map->type & BTRFS_BLOCK_GROUP_RAID1_MASK) {
-		if (op != BTRFS_MAP_READ) {
-			num_stripes = map->num_stripes;
-		} else if (mirror_num) {
-			stripe_index = mirror_num - 1;
-		} else {
-			stripe_index = find_live_mirror(fs_info, map, 0,
-					    dev_replace_is_ongoing);
-			mirror_num = stripe_index + 1;
-		}
-
-	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
-		if (op != BTRFS_MAP_READ) {
-			num_stripes = map->num_stripes;
-		} else if (mirror_num) {
-			stripe_index = mirror_num - 1;
-		} else {
-			mirror_num = 1;
-		}
-
-	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
-		u32 factor = map->num_stripes / map->sub_stripes;
-
-		stripe_index = (stripe_nr % factor) * map->sub_stripes;
-		stripe_nr /= factor;
-
-		if (op != BTRFS_MAP_READ)
-			num_stripes = map->sub_stripes;
-		else if (mirror_num)
-			stripe_index += mirror_num - 1;
-		else {
-			int old_stripe_index = stripe_index;
-			stripe_index = find_live_mirror(fs_info, map,
-					      stripe_index,
-					      dev_replace_is_ongoing);
-			mirror_num = stripe_index - old_stripe_index + 1;
-		}
-
-	} else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
-		if (op != BTRFS_MAP_READ || mirror_num > 1) {
-			/*
-			 * Needs full stripe mapping.
-			 *
-			 * Push stripe_nr back to the start of the full stripe
-			 * For those cases needing a full stripe, @stripe_nr
-			 * is the full stripe number.
-			 *
-			 * Originally we go raid56_full_stripe_start / full_stripe_len,
-			 * but that can be expensive.  Here we just divide
-			 * @stripe_nr with @data_stripes.
-			 */
-			stripe_nr /= data_stripes;
-
-			/* RAID[56] write or recovery. Return all stripes */
-			num_stripes = map->num_stripes;
-			max_errors = btrfs_chunk_max_errors(map);
-
-			/* Return the length to the full stripe end */
-			*length = min(logical + *length,
-				      raid56_full_stripe_start + em->start +
-				      btrfs_stripe_nr_to_offset(data_stripes)) -
-				  logical;
-			stripe_index = 0;
-			stripe_offset = 0;
-		} else {
-			ASSERT(mirror_num <= 1);
-			/* Just grab the data stripe directly. */
-			stripe_index = stripe_nr % data_stripes;
-			stripe_nr /= data_stripes;
-
-			/* We distribute the parity blocks across stripes */
-			stripe_index = (stripe_nr + stripe_index) % map->num_stripes;
-			if (op == BTRFS_MAP_READ && mirror_num < 1)
-				mirror_num = 1;
-		}
-	} else {
+	switch (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+	case BTRFS_BLOCK_GROUP_RAID0:
+		map_blocks_raid0(map, &io_geom);
+		break;
+	case BTRFS_BLOCK_GROUP_RAID1:
+	case BTRFS_BLOCK_GROUP_RAID1C3:
+	case BTRFS_BLOCK_GROUP_RAID1C4:
+		map_blocks_raid1(fs_info, map, &io_geom, dev_replace_is_ongoing);
+		break;
+	case BTRFS_BLOCK_GROUP_DUP:
+		map_blocks_dup(map, &io_geom);
+		break;
+	case BTRFS_BLOCK_GROUP_RAID10:
+		map_blocks_raid10(fs_info, map, &io_geom, dev_replace_is_ongoing);
+		break;
+	case BTRFS_BLOCK_GROUP_RAID5:
+	case BTRFS_BLOCK_GROUP_RAID6:
+		if (op != BTRFS_MAP_READ || io_geom.mirror_num > 1)
+			map_blocks_raid56_write(map, &io_geom, logical, length);
+		else
+			map_blocks_raid56_read(map, &io_geom);
+		break;
+	default:
 		/*
 		 * After this, stripe_nr is the number of stripes on this
 		 * device we have to walk to find the data, and stripe_index is
 		 * the number of our device in the stripe array
 		 */
-		stripe_index = stripe_nr % map->num_stripes;
-		stripe_nr /= map->num_stripes;
-		mirror_num = stripe_index + 1;
+		map_blocks_single(map, &io_geom);
+		break;
 	}
-	if (stripe_index >= map->num_stripes) {
+	if (io_geom.stripe_index >= map->num_stripes) {
 		btrfs_crit(fs_info,
 			   "stripe index math went horribly wrong, got stripe_index=%u, num_stripes=%u",
-			   stripe_index, map->num_stripes);
+			   io_geom.stripe_index, map->num_stripes);
 		ret = -EINVAL;
 		goto out;
 	}
 
-	num_alloc_stripes = num_stripes;
+	num_alloc_stripes = io_geom.num_stripes;
 	if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL &&
 	    op != BTRFS_MAP_READ)
 		/*
@@ -6401,14 +6630,11 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	 * physical block information on the stack instead of allocating an
 	 * I/O context structure.
 	 */
-	if (smap && num_alloc_stripes == 1 &&
-	    !(btrfs_need_stripe_tree_update(fs_info, map->type) &&
-	      op != BTRFS_MAP_READ) &&
-	    !((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) && mirror_num > 1)) {
-		ret = set_io_stripe(fs_info, op, logical, length, smap, map,
-				    stripe_index, stripe_offset, stripe_nr);
+	if (is_single_device_io(fs_info, smap, map, num_alloc_stripes, op,
+				io_geom.mirror_num)) {
+		ret = set_io_stripe(fs_info, logical, length, smap, map, &io_geom);
 		if (mirror_num_ret)
-			*mirror_num_ret = mirror_num;
+			*mirror_num_ret = io_geom.mirror_num;
 		*bioc_ret = NULL;
 		goto out;
 	}
@@ -6428,7 +6654,7 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	 * It's still mostly the same as other profiles, just with extra rotation.
 	 */
 	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
-	    (op != BTRFS_MAP_READ || mirror_num > 1)) {
+	    (op != BTRFS_MAP_READ || io_geom.mirror_num > 1)) {
 		/*
 		 * For RAID56 @stripe_nr is already the number of full stripes
 		 * before us, which is also the rotation value (needs to modulo
@@ -6437,28 +6663,31 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 		 * In this case, we just add @stripe_nr with @i, then do the
 		 * modulo, to reduce one modulo call.
 		 */
-		bioc->full_stripe_logical = em->start +
-			btrfs_stripe_nr_to_offset(stripe_nr * data_stripes);
-		for (int i = 0; i < num_stripes; i++) {
-			ret = set_io_stripe(fs_info, op, logical, length,
-					    &bioc->stripes[i], map,
-					    (i + stripe_nr) % num_stripes,
-					    stripe_offset, stripe_nr);
-			if (ret < 0)
-				break;
+		bioc->full_stripe_logical = map->start +
+			btrfs_stripe_nr_to_offset(io_geom.stripe_nr *
+						  nr_data_stripes(map));
+		for (int i = 0; i < io_geom.num_stripes; i++) {
+			struct btrfs_io_stripe *dst = &bioc->stripes[i];
+			u32 stripe_index;
+
+			stripe_index = (i + io_geom.stripe_nr) % io_geom.num_stripes;
+			dst->dev = map->stripes[stripe_index].dev;
+			dst->physical =
+				map->stripes[stripe_index].physical +
+				io_geom.stripe_offset +
+				btrfs_stripe_nr_to_offset(io_geom.stripe_nr);
 		}
 	} else {
 		/*
 		 * For all other non-RAID56 profiles, just copy the target
 		 * stripe into the bioc.
 		 */
-		for (i = 0; i < num_stripes; i++) {
-			ret = set_io_stripe(fs_info, op, logical, length,
-					    &bioc->stripes[i], map, stripe_index,
-					    stripe_offset, stripe_nr);
+		for (i = 0; i < io_geom.num_stripes; i++) {
+			ret = set_io_stripe(fs_info, logical, length,
+					    &bioc->stripes[i], map, &io_geom);
 			if (ret < 0)
 				break;
-			stripe_index++;
+			io_geom.stripe_index++;
 		}
 	}
 
@@ -6469,18 +6698,18 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 	}
 
 	if (op != BTRFS_MAP_READ)
-		max_errors = btrfs_chunk_max_errors(map);
+		io_geom.max_errors = btrfs_chunk_max_errors(map);
 
 	if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL &&
 	    op != BTRFS_MAP_READ) {
 		handle_ops_on_dev_replace(op, bioc, dev_replace, logical,
-					  &num_stripes, &max_errors);
+					  &io_geom.num_stripes, &io_geom.max_errors);
 	}
 
 	*bioc_ret = bioc;
-	bioc->num_stripes = num_stripes;
-	bioc->max_errors = max_errors;
-	bioc->mirror_num = mirror_num;
+	bioc->num_stripes = io_geom.num_stripes;
+	bioc->max_errors = io_geom.max_errors;
+	bioc->mirror_num = io_geom.mirror_num;
 
 out:
 	if (dev_replace_is_ongoing) {
@@ -6488,7 +6717,7 @@ out:
 		/* Unlock and let waiting writers proceed */
 		up_read(&dev_replace->rwsem);
 	}
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ret;
 }
 
@@ -6660,12 +6889,11 @@ static void btrfs_report_missing_device(struct btrfs_fs_info *fs_info,
 			      devid, uuid);
 }
 
-u64 btrfs_calc_stripe_length(const struct extent_map *em)
+u64 btrfs_calc_stripe_length(const struct btrfs_chunk_map *map)
 {
-	const struct map_lookup *map = em->map_lookup;
 	const int data_stripes = calc_data_stripes(map->type, map->num_stripes);
 
-	return div_u64(em->len, data_stripes);
+	return div_u64(map->chunk_len, data_stripes);
 }
 
 #if BITS_PER_LONG == 32
@@ -6734,9 +6962,7 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
 {
 	BTRFS_DEV_LOOKUP_ARGS(args);
 	struct btrfs_fs_info *fs_info = leaf->fs_info;
-	struct extent_map_tree *map_tree = &fs_info->mapping_tree;
-	struct map_lookup *map;
-	struct extent_map *em;
+	struct btrfs_chunk_map *map;
 	u64 logical;
 	u64 length;
 	u64 devid;
@@ -6770,35 +6996,22 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
 			return ret;
 	}
 
-	read_lock(&map_tree->lock);
-	em = lookup_extent_mapping(map_tree, logical, 1);
-	read_unlock(&map_tree->lock);
+	map = btrfs_find_chunk_map(fs_info, logical, 1);
 
 	/* already mapped? */
-	if (em && em->start <= logical && em->start + em->len > logical) {
-		free_extent_map(em);
+	if (map && map->start <= logical && map->start + map->chunk_len > logical) {
+		btrfs_free_chunk_map(map);
 		return 0;
-	} else if (em) {
-		free_extent_map(em);
+	} else if (map) {
+		btrfs_free_chunk_map(map);
 	}
 
-	em = alloc_extent_map();
-	if (!em)
-		return -ENOMEM;
-	map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
-	if (!map) {
-		free_extent_map(em);
+	map = btrfs_alloc_chunk_map(num_stripes, GFP_NOFS);
+	if (!map)
 		return -ENOMEM;
-	}
-
-	set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
-	em->map_lookup = map;
-	em->start = logical;
-	em->len = length;
-	em->orig_start = 0;
-	em->block_start = 0;
-	em->block_len = em->len;
 
+	map->start = logical;
+	map->chunk_len = length;
 	map->num_stripes = num_stripes;
 	map->io_width = btrfs_chunk_io_width(leaf, chunk);
 	map->io_align = btrfs_chunk_io_align(leaf, chunk);
@@ -6813,7 +7026,7 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
 	 */
 	map->sub_stripes = btrfs_raid_array[index].sub_stripes;
 	map->verified_stripes = 0;
-	em->orig_block_len = btrfs_calc_stripe_length(em);
+	map->stripe_size = btrfs_calc_stripe_length(map);
 	for (i = 0; i < num_stripes; i++) {
 		map->stripes[i].physical =
 			btrfs_stripe_offset_nr(leaf, chunk, i);
@@ -6829,7 +7042,7 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
 								    devid, uuid);
 			if (IS_ERR(map->stripes[i].dev)) {
 				ret = PTR_ERR(map->stripes[i].dev);
-				free_extent_map(em);
+				btrfs_free_chunk_map(map);
 				return ret;
 			}
 		}
@@ -6838,15 +7051,12 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
 				&(map->stripes[i].dev->dev_state));
 	}
 
-	write_lock(&map_tree->lock);
-	ret = add_extent_mapping(map_tree, em, 0);
-	write_unlock(&map_tree->lock);
+	ret = btrfs_add_chunk_map(fs_info, map);
 	if (ret < 0) {
 		btrfs_err(fs_info,
 			  "failed to add chunk map, start=%llu len=%llu: %d",
-			  em->start, em->len, ret);
+			  map->start, map->chunk_len, ret);
 	}
-	free_extent_map(em);
 
 	return ret;
 }
@@ -7156,26 +7366,21 @@ out_short_read:
 bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
 					struct btrfs_device *failing_dev)
 {
-	struct extent_map_tree *map_tree = &fs_info->mapping_tree;
-	struct extent_map *em;
-	u64 next_start = 0;
+	struct btrfs_chunk_map *map;
+	u64 next_start;
 	bool ret = true;
 
-	read_lock(&map_tree->lock);
-	em = lookup_extent_mapping(map_tree, 0, (u64)-1);
-	read_unlock(&map_tree->lock);
+	map = btrfs_find_chunk_map(fs_info, 0, U64_MAX);
 	/* No chunk at all? Return false anyway */
-	if (!em) {
+	if (!map) {
 		ret = false;
 		goto out;
 	}
-	while (em) {
-		struct map_lookup *map;
+	while (map) {
 		int missing = 0;
 		int max_tolerated;
 		int i;
 
-		map = em->map_lookup;
 		max_tolerated =
 			btrfs_get_num_tolerated_disk_barrier_failures(
 					map->type);
@@ -7193,18 +7398,15 @@ bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
 			if (!failing_dev)
 				btrfs_warn(fs_info,
 	"chunk %llu missing %d devices, max tolerance is %d for writable mount",
-				   em->start, missing, max_tolerated);
-			free_extent_map(em);
+				   map->start, missing, max_tolerated);
+			btrfs_free_chunk_map(map);
 			ret = false;
 			goto out;
 		}
-		next_start = extent_map_end(em);
-		free_extent_map(em);
+		next_start = map->start + map->chunk_len;
+		btrfs_free_chunk_map(map);
 
-		read_lock(&map_tree->lock);
-		em = lookup_extent_mapping(map_tree, next_start,
-					   (u64)(-1) - next_start);
-		read_unlock(&map_tree->lock);
+		map = btrfs_find_chunk_map(fs_info, next_start, U64_MAX - next_start);
 	}
 out:
 	return ret;
@@ -7697,20 +7899,15 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 				 u64 physical_offset, u64 physical_len)
 {
 	struct btrfs_dev_lookup_args args = { .devid = devid };
-	struct extent_map_tree *em_tree = &fs_info->mapping_tree;
-	struct extent_map *em;
-	struct map_lookup *map;
+	struct btrfs_chunk_map *map;
 	struct btrfs_device *dev;
 	u64 stripe_len;
 	bool found = false;
 	int ret = 0;
 	int i;
 
-	read_lock(&em_tree->lock);
-	em = lookup_extent_mapping(em_tree, chunk_offset, 1);
-	read_unlock(&em_tree->lock);
-
-	if (!em) {
+	map = btrfs_find_chunk_map(fs_info, chunk_offset, 1);
+	if (!map) {
 		btrfs_err(fs_info,
 "dev extent physical offset %llu on devid %llu doesn't have corresponding chunk",
 			  physical_offset, devid);
@@ -7718,12 +7915,11 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 		goto out;
 	}
 
-	map = em->map_lookup;
-	stripe_len = btrfs_calc_stripe_length(em);
+	stripe_len = btrfs_calc_stripe_length(map);
 	if (physical_len != stripe_len) {
 		btrfs_err(fs_info,
 "dev extent physical offset %llu on devid %llu length doesn't match chunk %llu, have %llu expect %llu",
-			  physical_offset, devid, em->start, physical_len,
+			  physical_offset, devid, map->start, physical_len,
 			  stripe_len);
 		ret = -EUCLEAN;
 		goto out;
@@ -7746,7 +7942,7 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 			if (map->verified_stripes >= map->num_stripes) {
 				btrfs_err(fs_info,
 				"too many dev extents for chunk %llu found",
-					  em->start);
+					  map->start);
 				ret = -EUCLEAN;
 				goto out;
 			}
@@ -7792,32 +7988,30 @@ static int verify_one_dev_extent(struct btrfs_fs_info *fs_info,
 	}
 
 out:
-	free_extent_map(em);
+	btrfs_free_chunk_map(map);
 	return ret;
 }
 
 static int verify_chunk_dev_extent_mapping(struct btrfs_fs_info *fs_info)
 {
-	struct extent_map_tree *em_tree = &fs_info->mapping_tree;
-	struct extent_map *em;
 	struct rb_node *node;
 	int ret = 0;
 
-	read_lock(&em_tree->lock);
-	for (node = rb_first_cached(&em_tree->map); node; node = rb_next(node)) {
-		em = rb_entry(node, struct extent_map, rb_node);
-		if (em->map_lookup->num_stripes !=
-		    em->map_lookup->verified_stripes) {
+	read_lock(&fs_info->mapping_tree_lock);
+	for (node = rb_first_cached(&fs_info->mapping_tree); node; node = rb_next(node)) {
+		struct btrfs_chunk_map *map;
+
+		map = rb_entry(node, struct btrfs_chunk_map, rb_node);
+		if (map->num_stripes != map->verified_stripes) {
 			btrfs_err(fs_info,
 			"chunk %llu has missing dev extent, have %d expect %d",
-				  em->start, em->map_lookup->verified_stripes,
-				  em->map_lookup->num_stripes);
+				  map->start, map->verified_stripes, map->num_stripes);
 			ret = -EUCLEAN;
 			goto out;
 		}
 	}
 out:
-	read_unlock(&em_tree->lock);
+	read_unlock(&fs_info->mapping_tree_lock);
 	return ret;
 }