On Tuesday 12 February 2008, Jan Engelhardt wrote: > On Feb 12 2008 08:49, Chris Mason wrote: > >> > This is a real issue on sparc where the default sun disk labels > >> > created use an initial partition where block zero aliases the disk > >> > label. It took me a few iterations before I figured out why every > >> > btrfs make would zero out my disk label :-/ > >> > >> Actually it seems this is only a problem with mkfs.btrfs, it clears > >> out the first 64 4K chunks of the disk for whatever reason. > > > >It is a good idea to remove supers from other filesystems. I also need to > > add zeroing at the end of the device as well. > > > >Looks like I misread the e2fs zeroing code. It zeros the whole external > > log device, and I assumed it also zero'd out the start of the main FS. > > > >So, if Btrfs starts zeroing at 1k, will that be acceptable for you? > > Something looks wrong here. Why would btrfs need to zero at all? > Superblock at 0, and done. Just like xfs. > (Yes, I had xfs on sparc before, so it's not like you NEED the > whitespace at the start of a partition.) I've had requests to move the super down to 64k to make room for bootloaders, which may not matter for sparc, but I don't really plan on different locations for different arches. 4k aligned is important given that sector sizes are growing. -chris - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
