1 files changed, 50 insertions, 105 deletions

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 2d0410344ea3..7c97b3301459 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -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;
 }
@@ -299,19 +282,8 @@ 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)
 {
         struct extent_map *em;
         struct rb_node *rb_node;
@@ -320,38 +292,42 @@ 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
@@ -365,38 +341,7 @@ 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) {
-                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);
-        goto found;
-
-        em = NULL;
-        goto out;
-
-found:
-        atomic_inc(&em->refs);
-out:
-        return em;
+        return __lookup_extent_mapping(tree, start, len, 0);
 }
 
 /**