f2fs: check number of blocks in a current section

In cfd66bb7 ("f2fs: fix deadloop in foreground GC"), we needed to check
the number of blocks in a section instead of the segment.

Fixes: cfd66bb7 ("f2fs: fix deadloop in foreground GC")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.h

@@ -561,23 +561,22 @@ static inline bool has_curseg_enough_space(struct f2fs_sb_info *sbi,
 			unsigned int node_blocks, unsigned int dent_blocks)
 {
 
-	unsigned int segno, left_blocks;
+	unsigned segno, left_blocks;
 	int i;
 
-	/* check current node segment */
+	/* check current node sections in the worst case. */
 	for (i = CURSEG_HOT_NODE; i <= CURSEG_COLD_NODE; i++) {
 		segno = CURSEG_I(sbi, i)->segno;
-		left_blocks = f2fs_usable_blks_in_seg(sbi, segno) -
-				get_seg_entry(sbi, segno)->ckpt_valid_blocks;
-
+		left_blocks = CAP_BLKS_PER_SEC(sbi) -
+				get_ckpt_valid_blocks(sbi, segno, true);
 		if (node_blocks > left_blocks)
 			return false;
 	}
 
-	/* check current data segment */
+	/* check current data section for dentry blocks. */
 	segno = CURSEG_I(sbi, CURSEG_HOT_DATA)->segno;
-	left_blocks = f2fs_usable_blks_in_seg(sbi, segno) -
-			get_seg_entry(sbi, segno)->ckpt_valid_blocks;
+	left_blocks = CAP_BLKS_PER_SEC(sbi) -
+			get_ckpt_valid_blocks(sbi, segno, true);
 	if (dent_blocks > left_blocks)
 		return false;
 	return true;
@@ -626,7 +625,7 @@ static inline bool has_not_enough_free_secs(struct f2fs_sb_info *sbi,
 
 	if (free_secs > upper_secs)
 		return false;
-	else if (free_secs <= lower_secs)
+	if (free_secs <= lower_secs)
 		return true;
 	return !curseg_space;
 }