tree c0043de3cbcea1f447c3414c1a5e63e007f2da2e
parent 7fd9e544fbb10c6ae4b4953f6063560c8eeae6e8
author Jaegeuk Kim <jaegeuk.kim@samsung.com> 1384235396 +0900
committer Jaegeuk Kim <jaegeuk.kim@samsung.com> 1387761480 +0900

f2fs: add key functions for small discards

This patch adds key functions to activate the small discard feature.

Note that this procedure is conducted during the checkpoint only.

In flush_sit_entries(), when a new dirty sit entry is flushed, f2fs calls
add_discard_addrs() which searches candidates to be discarded.
The candidates should be marked *invalidated* and also previous checkpoint
recognizes it as *valid*.

At the end of a checkpoint procedure, f2fs throws discards based on the
discard entry list.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>