Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid

[cascardo/linux.git] / fs / btrfs / extent_map.c

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 30c9365..2c726b7 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -36,7 +36,7 @@ void extent_map_exit(void)
 void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
 {
        tree->map.rb_node = NULL;
-       spin_lock_init(&tree->lock);
+       rwlock_init(&tree->lock);
 }
 
 /**
@@ -198,6 +198,56 @@ 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)
+{
+       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->start != start || !em);
+
+       if (!em)
+               goto out;
+
+       clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+       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);
+       }
+
+       free_extent_map(em);
+out:
+       write_unlock(&tree->lock);
+       return ret;
+
+}
+
 /**
  * add_extent_mapping - add new extent map to the extent tree
  * @tree:      tree to insert new map in
@@ -222,7 +272,6 @@ int add_extent_mapping(struct extent_map_tree *tree,
                ret = -EEXIST;
                goto out;
        }
-       assert_spin_locked(&tree->lock);
        rb = tree_insert(&tree->map, em->start, &em->rb_node);
        if (rb) {
                ret = -EEXIST;
@@ -285,7 +334,6 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
        struct rb_node *next = NULL;
        u64 end = range_end(start, len);
 
-       assert_spin_locked(&tree->lock);
        rb_node = __tree_search(&tree->map, start, &prev, &next);
        if (!rb_node && prev) {
                em = rb_entry(prev, struct extent_map, rb_node);
@@ -318,6 +366,54 @@ out:
        return em;
 }
 
+/**
+ * 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
@@ -331,7 +427,6 @@ int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
        int ret = 0;
 
        WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
-       assert_spin_locked(&tree->lock);
        rb_erase(&em->rb_node, &tree->map);
        em->in_tree = 0;
        return ret;