Btrfs: Extent based page cache code. This uses an rbtree of extents and tests

instead of buffer heads.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 89 insertions, 0 deletions

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
new file mode 100644
index 0000000..108944a
--- /dev/null
+++ b/fs/btrfs/extent_map.h
@@ -0,0 +1,89 @@
+#ifndef __EXTENTMAP__
+#define __EXTENTMAP__
+
+#include <linux/rbtree.h>
+
+#define EXTENT_MAP_INLINE (u64)-2
+#define EXTENT_MAP_DELALLOC (u64)-1
+
+struct extent_map_tree {
+	struct rb_root map;
+	struct rb_root state;
+	struct address_space *mapping;
+	rwlock_t lock;
+};
+
+/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
+struct extent_map {
+	u64 start;
+	u64 end; /* inclusive */
+	int in_tree;
+	struct rb_node rb_node;
+	/* block_start and block_end are in bytes */
+	u64 block_start;
+	u64 block_end; /* inclusive */
+	struct block_device *bdev;
+	atomic_t refs;
+};
+
+/* note, this must start with the same fields as fs/extent_map.c:tree_entry */
+struct extent_state {
+	u64 start;
+	u64 end; /* inclusive */
+	int in_tree;
+	struct rb_node rb_node;
+	wait_queue_head_t wq;
+	atomic_t refs;
+	unsigned long state;
+	struct list_head list;
+};
+
+struct extent_buffer {
+	u64 start;
+	u64 end; /* inclusive */
+	char *addr;
+	struct page *pages[];
+};
+
+typedef struct extent_map *(get_extent_t)(struct inode *inode,
+					  struct page *page,
+					  size_t page_offset,
+					  u64 start, u64 end,
+					  int create);
+
+void extent_map_tree_init(struct extent_map_tree *tree,
+			  struct address_space *mapping, gfp_t mask);
+struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
+					 u64 start, u64 end);
+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);
+int try_release_extent_mapping(struct extent_map_tree *tree, struct page *page);
+int lock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
+int unlock_extent(struct extent_map_tree *tree, u64 start, u64 end, gfp_t mask);
+struct extent_map *alloc_extent_map(gfp_t mask);
+void free_extent_map(struct extent_map *em);
+int extent_read_full_page(struct extent_map_tree *tree, struct page *page,
+			  get_extent_t *get_extent);
+void __init extent_map_init(void);
+void __exit extent_map_exit(void);
+int extent_clean_all_trees(struct extent_map_tree *tree);
+int set_extent_uptodate(struct extent_map_tree *tree, u64 start, u64 end,
+			gfp_t mask);
+int set_extent_new(struct extent_map_tree *tree, u64 start, u64 end,
+		   gfp_t mask);
+int set_extent_dirty(struct extent_map_tree *tree, u64 start, u64 end,
+		     gfp_t mask);
+int extent_invalidatepage(struct extent_map_tree *tree,
+			  struct page *page, unsigned long offset);
+int extent_write_full_page(struct extent_map_tree *tree, struct page *page,
+			  get_extent_t *get_extent,
+			  struct writeback_control *wbc);
+int extent_prepare_write(struct extent_map_tree *tree,
+			 struct inode *inode, struct page *page,
+			 unsigned from, unsigned to, get_extent_t *get_extent);
+int extent_commit_write(struct extent_map_tree *tree,
+			struct inode *inode, struct page *page,
+			unsigned from, unsigned to);
+int set_range_dirty(struct extent_map_tree *tree, u64 start, u64 end);
+#endif