1 files changed, 85 insertions, 0 deletions

diff --git a/kernel/fs/btrfs/extent_map.h b/kernel/fs/btrfs/extent_map.h
new file mode 100644
index 000000000..b2991fd85
--- /dev/null
+++ b/kernel/fs/btrfs/extent_map.h
@@ -0,0 +1,85 @@
+#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 */
+#define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
+#define EXTENT_FLAG_FILLING 5 /* Filling in a preallocated extent */
+#define EXTENT_FLAG_FS_MAPPING 6 /* filesystem extent mapping type */
+
+struct extent_map {
+	struct rb_node rb_node;
+
+	/* all of these are in bytes */
+	u64 start;
+	u64 len;
+	u64 mod_start;
+	u64 mod_len;
+	u64 orig_start;
+	u64 orig_block_len;
+	u64 ram_bytes;
+	u64 block_start;
+	u64 block_len;
+	u64 generation;
+	unsigned long flags;
+	struct block_device *bdev;
+	atomic_t refs;
+	unsigned int compress_type;
+	struct list_head list;
+};
+
+struct extent_map_tree {
+	struct rb_root map;
+	struct list_head modified_extents;
+	rwlock_t lock;
+};
+
+static inline int extent_map_in_tree(const struct extent_map *em)
+{
+	return !RB_EMPTY_NODE(&em->rb_node);
+}
+
+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);
+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 modified);
+int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
+void replace_extent_mapping(struct extent_map_tree *tree,
+			    struct extent_map *cur,
+			    struct extent_map *new,
+			    int modified);
+
+struct extent_map *alloc_extent_map(void);
+void free_extent_map(struct extent_map *em);
+int __init extent_map_init(void);
+void extent_map_exit(void);
+int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
+void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
+struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
+					 u64 start, u64 len);
+#endif