f2fs: allocate HOT_DATA for IPU writes

Let's split IPU writes in hot data area to improve the GC efficiency.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: Jaegeuk Kim

fs/f2fs/segment.c

@@ -3689,7 +3689,8 @@ static int __get_segment_type_6(struct f2fs_io_info *fio)
 
 		if (file_is_hot(inode) ||
 				is_inode_flag_set(inode, FI_HOT_DATA) ||
-				f2fs_is_cow_file(inode))
+				f2fs_is_cow_file(inode) ||
+				is_inode_flag_set(inode, FI_NEED_IPU))
 			return CURSEG_HOT_DATA;
 		return f2fs_rw_hint_to_seg_type(F2FS_I_SB(inode),
 						inode->i_write_hint);