f2fs: record node block allocation in dnode_of_data

This patch introduces recording node block allocation in dnode_of_data.
This information helps to figure out whether any node block is allocated during
specific file operations.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
3 files changed