On Sat, Mar 19, 2022 at 12:23:04PM -0400, Theodore Ts'o wrote: > So the thing that I've been waiting to do for a while is to replace > the whole data=ordered vs data=writeback and dioread_nolock and > dioread_lock is a complete reworking of the ext4 buffered writeback > path, where we write the data blocks *first*, and only then update the > ext4 metadata. > *) Determining where the new allocated data blockblocks should be, and > preventing those blocks from being used for any other purposes, but > *not* updating the file system metadata to reflect that change. > > *) Submit the data block write > > *) On write completion, update the metadata blocks in a kernel thread. I think that would be easily done by switching to the iomap buffered I/O code, which is very much built around that model.