Commit 4d2c8f62 authored by Li Zefan's avatar Li Zefan Committed by Chris Mason
Browse files

Btrfs: clean up code for merging extent maps 



unpin_extent_cache() and add_extent_mapping() shares the same code
that merges extent maps.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent ed64f066

fs/btrfs/extent_map.c

+21 −38
Original line number Diff line number Diff line
@@ -183,22 +183,10 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next) 
	return 0;

}



int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)

static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)

{

	int ret = 0;

	struct extent_map *merge = NULL;

	struct rb_node *rb;

	struct extent_map *em;



	write_lock(&tree->lock);

	em = lookup_extent_mapping(tree, start, len);



	WARN_ON(!em || em->start != start);



	if (!em)

		goto out;



	clear_bit(EXTENT_FLAG_PINNED, &em->flags);



	if (em->start != 0) {

		rb = rb_prev(&em->rb_node);
@@ -225,6 +213,24 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len) 
		merge->in_tree = 0;

		free_extent_map(merge);

	}

}



int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)

{

	int ret = 0;

	struct extent_map *em;



	write_lock(&tree->lock);

	em = lookup_extent_mapping(tree, start, len);



	WARN_ON(!em || em->start != start);



	if (!em)

		goto out;



	clear_bit(EXTENT_FLAG_PINNED, &em->flags);



	try_merge_map(tree, em);



	free_extent_map(em);

out:
@@ -247,7 +253,6 @@ int add_extent_mapping(struct extent_map_tree *tree, 
		       struct extent_map *em)

{

	int ret = 0;

	struct extent_map *merge = NULL;

	struct rb_node *rb;

	struct extent_map *exist;
@@ -263,30 +268,8 @@ int add_extent_mapping(struct extent_map_tree *tree, 
		goto out;

	}

	atomic_inc(&em->refs);

	if (em->start != 0) {

		rb = rb_prev(&em->rb_node);

		if (rb)

			merge = rb_entry(rb, struct extent_map, rb_node);

		if (rb && mergable_maps(merge, em)) {

			em->start = merge->start;

			em->len += merge->len;

			em->block_len += merge->block_len;

			em->block_start = merge->block_start;

			merge->in_tree = 0;

			rb_erase(&merge->rb_node, &tree->map);

			free_extent_map(merge);

		}

	 }

	rb = rb_next(&em->rb_node);

	if (rb)

		merge = rb_entry(rb, struct extent_map, rb_node);

	if (rb && mergable_maps(em, merge)) {

		em->len += merge->len;

		em->block_len += merge->len;

		rb_erase(&merge->rb_node, &tree->map);

		merge->in_tree = 0;

		free_extent_map(merge);

	}



	try_merge_map(tree, em);

out:

	return ret;

}