On Wed, Nov 22, 2023 at 05:11:18AM -0800, Christoph Hellwig wrote: > On Wed, Nov 22, 2023 at 01:29:46PM +0100, Jan Kara wrote: > > writeback bit set. XFS plays the revalidation sequence counter games > > because of this so we'd have to do something similar for ext2. Not that I'd > > care as much about ext2 writeback performance but it should not be that > > hard and we'll definitely need some similar solution for ext4 anyway. Can > > you give that a try (as a followup "performance improvement" patch). > > Darrick has mentioned that he is looking into lifting more of the > validation sequence counter validation into iomap. I think that was me, as part of aligning the writeback path with the ->iomap_valid() checks in the write path after we lock the folio we instantiated for the write. It's basically the same thing - once we have a locked folio, we have to check that the cached iomap is still valid before we use it for anything. I need to find the time to get back to that, though. -Dave. -- Dave Chinner david@xxxxxxxxxxxxx