1 files changed, 62 insertions, 0 deletions

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
new file mode 100644
index 000000000000..fb6eeef06bb0
--- /dev/null
+++ b/fs/btrfs/extent_map.h
@@ -0,0 +1,62 @@
+#ifndef __EXTENTMAP__
+#define __EXTENTMAP__
+
+#include <linux/rbtree.h>
+
+#define EXTENT_MAP_LAST_BYTE (u64)-4
+#define EXTENT_MAP_HOLE (u64)-3
+#define EXTENT_MAP_INLINE (u64)-2
+#define EXTENT_MAP_DELALLOC (u64)-1
+
+/* bits for the flags field */
+#define EXTENT_FLAG_PINNED 0 /* this entry not yet on disk, don't free it */
+#define EXTENT_FLAG_COMPRESSED 1
+#define EXTENT_FLAG_VACANCY 2 /* no file extent item found */
+#define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
+
+struct extent_map {
+        struct rb_node rb_node;
+
+        /* all of these are in bytes */
+        u64 start;
+        u64 len;
+        u64 orig_start;
+        u64 block_start;
+        u64 block_len;
+        unsigned long flags;
+        struct block_device *bdev;
+        atomic_t refs;
+        int in_tree;
+};
+
+struct extent_map_tree {
+        struct rb_root map;
+        spinlock_t lock;
+};
+
+static inline u64 extent_map_end(struct extent_map *em)
+{
+        if (em->start + em->len < em->start)
+                return (u64)-1;
+        return em->start + em->len;
+}
+
+static inline u64 extent_map_block_end(struct extent_map *em)
+{
+        if (em->block_start + em->block_len < em->block_start)
+                return (u64)-1;
+        return em->block_start + em->block_len;
+}
+
+void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask);
+struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
+                                         u64 start, u64 len);
+int add_extent_mapping(struct extent_map_tree *tree,
+                       struct extent_map *em);
+int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
+
+struct extent_map *alloc_extent_map(gfp_t mask);
+void free_extent_map(struct extent_map *em);
+int __init extent_map_init(void);
+void extent_map_exit(void);
+#endif