On Thu, Jul 14, 2011 at 11:18:15AM +0800, Li Zefan wrote:
> lookup_extent_map() and search_extent_map() can share most of code.
>
> Signed-off-by: Li Zefan
> ---
> fs/btrfs/extent_map.c | 85
> +
> 1 files changed, 29 insertions(+), 56 deletions(-)
>
> diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
> index 911a9db..df7a803 100644
> --- a/fs/btrfs/extent_map.c
> +++ b/fs/btrfs/extent_map.c
> @@ -299,19 +299,8 @@ static u64 range_end(u64 start, u64 len)
> return start + len;
> }
>
> -/**
> - * lookup_extent_mapping - lookup extent_map
> - * @tree:tree to lookup in
> - * @start: byte offset to start the search
> - * @len: length of the lookup range
> - *
> - * Find and return the first extent_map struct in @tree that intersects the
> - * [start, len] range. There may be additional objects in the tree that
> - * intersect, so check the object returned carefully to make sure that no
> - * additional lookups are needed.
> - */
> -struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
> - u64 start, u64 len)
> +struct extent_map *__lookup_extent_mapping(struct extent_map_tree *tree,
> +u64 start, u64 len, int strict)
just minor thing: can be defined static
> {
> struct extent_map *em;
> struct rb_node *rb_node;
> @@ -320,38 +309,42 @@ struct extent_map *lookup_extent_mapping(struct
> extent_map_tree *tree,
> u64 end = range_end(start, len);
>
> rb_node = __tree_search(&tree->map, start, &prev, &next);
> - if (!rb_node && prev) {
> - em = rb_entry(prev, struct extent_map, rb_node);
> - if (end > em->start && start < extent_map_end(em))
> - goto found;
> - }
> - if (!rb_node && next) {
> - em = rb_entry(next, struct extent_map, rb_node);
> - if (end > em->start && start < extent_map_end(em))
> - goto found;
> - }
> if (!rb_node) {
> - em = NULL;
> - goto out;
> - }
> - if (IS_ERR(rb_node)) {
> - em = ERR_CAST(rb_node);
> - goto out;
> + if (prev)
> + rb_node = prev;
> + else if (next)
> + rb_node = next;
> + else
> + return NULL;
> }
> +
> em = rb_entry(rb_node, struct extent_map, rb_node);
> - if (end > em->start && start < extent_map_end(em))
> - goto found;
>
> - em = NULL;
> - goto out;
> + if (strict && !(end > em->start && start < extent_map_end(em)))
> + return NULL;
>
> -found:
> atomic_inc(&em->refs);
> -out:
> return em;
> }
>
> /**
> + * lookup_extent_mapping - lookup extent_map
> + * @tree:tree to lookup in
> + * @start: byte offset to start the search
> + * @len: length of the lookup range
> + *
> + * Find and return the first extent_map struct in @tree that intersects the
> + * [start, len] range. There may be additional objects in the tree that
> + * intersect, so check the object returned carefully to make sure that no
> + * additional lookups are needed.
> + */
> +struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
> + u64 start, u64 len)
> +{
> + return __lookup_extent_mapping(tree, start, len, 1);
> +}
> +
> +/**
> * search_extent_mapping - find a nearby extent map
> * @tree:tree to lookup in
> * @start: byte offset to start the search
> @@ -365,27 +358,7 @@ out:
> struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
>u64 start, u64 len)
> {
> - struct extent_map *em;
> - struct rb_node *rb_node;
> - struct rb_node *prev = NULL;
> - struct rb_node *next = NULL;
> -
> - rb_node = __tree_search(&tree->map, start, &prev, &next);
> - if (!rb_node && prev) {
> - em = rb_entry(prev, struct extent_map, rb_node);
> - goto found;
> - }
> - if (!rb_node && next) {
> - em = rb_entry(next, struct extent_map, rb_node);
> - goto found;
> - }
> - if (!rb_node)
> - return NULL;
> -
> - em = rb_entry(rb_node, struct extent_map, rb_node);
> -found:
> - atomic_inc(&em->refs);
> - return em;
> + return __lookup_extent_mapping(tree, start, len, 0);
> }
>
> /**
> --
> 1.7.3.1
> --
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