f2fs: do not set free of current section

For the case when sbi->segs_per_sec > 1, take section:segment = 5 for
example, if segment 1 is just used and allocate new segment 2, and the
blocks of segment 1 is invalidated, at this time, the previous code will
use __set_test_and_free to free the free_secmap and free_sections++,
this is not correct since it is still a current section, so fix it.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.h

@@ -448,6 +448,8 @@ static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
 	if (test_and_clear_bit(segno, free_i->free_segmap)) {
 		free_i->free_segments++;
 
+		if (IS_CURSEC(sbi, secno))
+			goto skip_free;
 		next = find_next_bit(free_i->free_segmap,
 				start_segno + sbi->segs_per_sec, start_segno);
 		if (next >= start_segno + sbi->segs_per_sec) {
@@ -455,6 +457,7 @@ static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
 				free_i->free_sections++;
 		}
 	}
+skip_free:
 	spin_unlock(&free_i->segmap_lock);
 }