On Mon, Oct 05, 2020 at 07:51:10PM -0700, Darrick J. Wong wrote: > > > Could /somebody/ please document the ondisk format changes that are > > > associated with this feature? > > > > I pretty much had to sort it out by looking at a combination of > > e2fsprogs and the kernel, and a lot of experimentation, until I ended up > > with something that the kernel was completely happy with without a > > single complaint. > > > > I'd be happy to write up a summary of the format. > > Seems like a good idea, particularly since you're asking for a format > change that requires kernel support and the ondisk format documentation > lives under Documentation/. That said... > > If you set up the rest of the metadata consistently with it (for > > instance, 0 free blocks and 0 free inodes), you'll only get a single > > complaint, from the e2fsck equivalent of block_validity. See > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=956509 for details on > > that; > > ...Ted shot down this whole thing six months ago. > > The Debian bug database is /not/ the designated forum to discuss changes > to the ondisk format; linux-ext4 is. What Josh is proposing I'm pretty sure would also break "e2fsck -E unshare_blocks", so that's another reason not to accept this as a valid format change. As far as I'm concerned, contrib/e2fsdroid is the canonical definition of how to create valid file systems with shared_blocks. - Ted
