nfsd4: cl_count is unused

[safe/jmp/linux-2.6] / fs / btrfs / extent_map.c

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 5bc7a0d..428fcac 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -155,20 +155,6 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
        return NULL;
 }
 
-/*
- * look for an offset in the tree, and if it can't be found, return
- * the first offset we can find smaller than 'offset'.
- */
-static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
-{
-       struct rb_node *prev;
-       struct rb_node *ret;
-       ret = __tree_search(root, offset, &prev, NULL);
-       if (!ret)
-               return prev;
-       return ret;
-}
-
 /* check to see if two extent_map structs are adjacent and safe to merge */
 static int mergable_maps(struct extent_map *prev, struct extent_map *next)
 {
@@ -208,7 +194,7 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
        write_lock(&tree->lock);
        em = lookup_extent_mapping(tree, start, len);
 
-       WARN_ON(em->start != start || !em);
+       WARN_ON(!em || em->start != start);
 
        if (!em)
                goto out;
@@ -256,7 +242,7 @@ out:
  * Insert @em into @tree or perform a simple forward/backward merge with
  * existing mappings.  The extent_map struct passed in will be inserted
  * into the tree directly, with an additional reference taken, or a
- * reference dropped if the merge attempt was sucessfull.
+ * reference dropped if the merge attempt was successfull.
  */
 int add_extent_mapping(struct extent_map_tree *tree,
                       struct extent_map *em)
@@ -367,6 +353,54 @@ out:
 }
 
 /**
+ * search_extent_mapping - find a nearby 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.
+ *
+ * If one can't be found, any nearby extent may be returned
+ */
+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) {
+               em = NULL;
+               goto out;
+       }
+       if (IS_ERR(rb_node)) {
+               em = ERR_PTR(PTR_ERR(rb_node));
+               goto out;
+       }
+       em = rb_entry(rb_node, struct extent_map, rb_node);
+       goto found;
+
+       em = NULL;
+       goto out;
+
+found:
+       atomic_inc(&em->refs);
+out:
+       return em;
+}
+
+/**
  * remove_extent_mapping - removes an extent_map from the extent tree
  * @tree:      extent tree to remove from
  * @em:                extent map beeing removed