f2fs: use bitmap in discard_entry

This patch changes to use bitmap instead of extent in struct discard_entry
to indicate discard range in one segment, for fragmented space, this
implementation can save memory footprint.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 8741d5102f14..43b6e1eeceb6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -182,11 +182,11 @@ struct inode_entry {
 	struct inode *inode;	/* vfs inode pointer */
 };
 
-/* for the list of blockaddresses to be discarded */
+/* for the bitmap indicate blocks to be discarded */
 struct discard_entry {
 	struct list_head list;	/* list head */
-	block_t blkaddr;	/* block address to be discarded */
-	int len;		/* # of consecutive blocks of the discard */
+	block_t start_blkaddr;	/* start blockaddr of current segment */
+	unsigned char discard_map[SIT_VBLOCK_MAP_SIZE];	/* segment discard bitmap */
 };
 
 enum {