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 000000000000..108944aab4bd
--- /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