f2fs: introduce readahead mode of node pages
Previously, f2fs reads several node pages ahead when get_dnode_of_data is called
with RDONLY_NODE flag.
And, this flag is set by the following functions.
- get_data_block_ro
- get_lock_data_page
- do_write_data_page
- truncate_blocks
- truncate_hole
However, this readahead mechanism is initially introduced for the use of
get_data_block_ro to enhance the sequential read performance.
So, let's clarify all the cases with the additional modes as follows.
enum {
ALLOC_NODE, /* allocate a new node page if needed */
LOOKUP_NODE, /* look up a node without readahead */
LOOKUP_NODE_RA, /*
* look up a node with readahead called
* by get_datablock_ro.
*/
}
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index cc2213a..be7ae70 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -125,11 +125,15 @@
* file keeping -1 as its node offset to
* distinguish from index node blocks.
*/
-#define RDONLY_NODE 1 /*
- * specify a read-only mode when getting
- * a node block. 0 is read-write mode.
- * used by get_dnode_of_data().
+enum {
+ ALLOC_NODE, /* allocate a new node page if needed */
+ LOOKUP_NODE, /* look up a node without readahead */
+ LOOKUP_NODE_RA, /*
+ * look up a node with readahead called
+ * by get_datablock_ro.
*/
+};
+
#define F2FS_LINK_MAX 32000 /* maximum link count per file */
/* for in-memory extent cache entry */