diff options
| -rw-r--r-- | fs/btrfs/extent_map.c | 61 |
1 files changed, 49 insertions, 12 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index ba46f7911d9..f5a04eb9a2a 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -31,6 +31,14 @@ void extent_map_exit(void) kmem_cache_destroy(extent_map_cache); } +/** + * extent_map_tree_init - initialize extent map tree + * @tree: tree to initialize + * @mask: flags for memory allocations during tree operations + * + * Initialize the extent tree @tree. Should be called for each new inode + * or other user of the extent_map interface. + */ void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask) { tree->map.rb_node = NULL; @@ -39,6 +47,14 @@ void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask) } EXPORT_SYMBOL(extent_map_tree_init); +/** + * alloc_extent_map - allocate new extent map structure + * @mask: memory allocation flags + * + * Allocate a new extent_map structure. The new structure is + * returned with a reference count of one and needs to be + * freed using free_extent_map() + */ struct extent_map *alloc_extent_map(gfp_t mask) { struct extent_map *em; @@ -52,6 +68,13 @@ struct extent_map *alloc_extent_map(gfp_t mask) } EXPORT_SYMBOL(alloc_extent_map); +/** + * free_extent_map - drop reference count of an extent_map + * @em: extent map beeing releasead + * + * Drops the reference out on @em by one and free the structure + * if the reference count hits zero. + */ void free_extent_map(struct extent_map *em) { if (!em) @@ -166,10 +189,15 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next) return 0; } -/* - * add_extent_mapping tries a simple forward/backward merge with existing - * mappings. The extent_map struct passed in will be inserted into - * the tree directly (no copies made, just a reference taken). +/** + * add_extent_mapping - add new extent map to the extent tree + * @tree: tree to insert new map in + * @em: map to insert + * + * Insert @em into @tree or perform a simple forward/backward merge with + * existing mappings. The extent_map struct passed in will be inserted + * into the tree directly, with an additional reference taken, or a + * reference dropped if the merge attempt was sucessfull. */ int add_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) @@ -220,11 +248,16 @@ static u64 range_end(u64 start, u64 len) return start + len; } -/* - * lookup_extent_mapping returns the first extent_map struct in the - * tree that intersects the [start, len] range. There may - * be additional objects in the tree that intersect, so check the object - * returned carefully to make sure you don't need additional lookups. +/** + * lookup_extent_mapping - lookup 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. There may be additional objects in the tree that + * intersect, so check the object returned carefully to make sure that no + * additional lookups are needed. */ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, u64 start, u64 len) @@ -273,9 +306,13 @@ out: } EXPORT_SYMBOL(lookup_extent_mapping); -/* - * removes an extent_map struct from the tree. No reference counts are - * dropped, and no checks are done to see if the range is in use +/** + * remove_extent_mapping - removes an extent_map from the extent tree + * @tree: extent tree to remove from + * @em: extent map beeing removed + * + * Removes @em from @tree. No reference counts are dropped, and no checks + * are done to see if the range is in use */ int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) { |