[PATCH] ext4: do not mark inode dirty which is already dirtied under append-write scenario

[Liu Song]

Hi,

Any comments on this? Considering the most extreme scenario
where a file is appended with only one byte each time,
"jbd2_journal_dirty_metadata" will be executed because i_size
has changed. Therefore, it is better to update raw_inode's size
after the writeback is completed, which can also ensure the
consistency of metadata and data, and obtain better performance
benefits in high-frequency append write scenarios.

Thanks