Btrfs: clean up code for extent_map lookup
lookup_extent_map() and search_extent_map() can share most of code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
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
@@ -299,6 +299,34 @@
return start + len;
}
+struct extent_map *__lookup_extent_mapping(struct extent_map_tree *tree,
+ u64 start, u64 len, int strict)
+{
+ struct extent_map *em;
+ struct rb_node *rb_node;
+ struct rb_node *prev = NULL;
+ struct rb_node *next = NULL;
+ u64 end = range_end(start, len);
+
+ rb_node = __tree_search(&tree->map, start, &prev, &next);
+ if (!rb_node) {
+ 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 (strict && !(end > em->start && start < extent_map_end(em)))
+ return NULL;
+
+ atomic_inc(&em->refs);
+ return em;
+}
+
/**
* lookup_extent_mapping - lookup extent_map
* @tree: tree to lookup in
@@ -313,42 +341,7 @@
struct extent_map *lookup_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;
- 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;
- }
- 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;
-
-found:
- atomic_inc(&em->refs);
-out:
- return em;
+ return __lookup_extent_mapping(tree, start, len, 1);
}
/**
@@ -365,27 +358,7 @@
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);
}
/**