f2fs: node segment is prior to data segment selected victim

As data segment gc may lead dnode dirty, so the greedy cost for data segment
should be valid blocks * 2, that is data segment is prior to node segment.
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/gc.c

@@ -242,6 +242,16 @@ static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 }
 
+static unsigned int get_greedy_cost(struct f2fs_sb_info *sbi,
+						unsigned int segno)
+{
+	unsigned int valid_blocks =
+			get_valid_blocks(sbi, segno, sbi->segs_per_sec);
+
+	return IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
+				valid_blocks * 2 : valid_blocks;
+}
+
 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 			unsigned int segno, struct victim_sel_policy *p)
 {
@@ -250,7 +260,7 @@ static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 
 	/* alloc_mode == LFS */
 	if (p->gc_mode == GC_GREEDY)
-		return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
+		return get_greedy_cost(sbi, segno);
 	else
 		return get_cb_cost(sbi, segno);
 }