f2fs: alloc new section if curseg is not the first seg in its zone

If curseg is not the first segment in its zone, the zone is not empty.
A new section should be allocated and avoid resetting the old zone.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Sheng Yong <shengyong@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -5187,7 +5187,8 @@ static int fix_curseg_write_pointer(struct f2fs_sb_info *sbi, int type)
 	}
 
 	/* Allocate a new section if it's not new. */
-	if (cs->next_blkoff) {
+	if (cs->next_blkoff ||
+	    cs->segno != GET_SEG_FROM_SEC(sbi, GET_ZONE_FROM_SEC(sbi, cs_section))) {
 		unsigned int old_segno = cs->segno, old_blkoff = cs->next_blkoff;
 
 		f2fs_allocate_new_section(sbi, type, true);