tree e5c335396c512c72d5c324f789a8ddae93340b0c
parent 66d36a2944df461448159be5af13049dd2689e77
author Jaegeuk Kim <jaegeuk.kim@samsung.com> 1361851846 +0900
committer Jaegeuk Kim <jaegeuk.kim@samsung.com> 1363608033 +0900

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>