Hello, These patches modify ext4 so that whenever inode with journalled data is written back we make sure we writeout all the dirty data the inode has. Previously this was not the case as pages with journalled data that were still part of running (or committing) transaction appeared as clean to the writeback code. As a result we can remove workarounds for inodes with journalled data from multiple places. In particular, we make sure a page is marked as dirty as soon as it has any data to write (even though it is part of the running transaction) and in ext4_writepages() we make sure appropriate transaction is committed (in WB_SYNC_ALL mode) and then go writing back pages (effectively performing a checkpoint for the inode). Thus after WB_SYNC_ALL writeback all pages for the inode are guaranteed to be clean (providing there were no new pages dirtied) the same way this is guaranteed for non-journaled data. The downside of this change is that workloads that use journalled data and frequently redirty pages and call fsync(2) will see more IO happening (more pages will get checkpointed). But given low amount of users of data=journal mode and their nature, I deem the code simplification worth it. Honza
