The "sparse file" errors are a different problem. It's actually a misleading error message: what's happening is that GRUB's btrfs implementation doesn't implement the file read hook interface for returning blocklists to calling code. I posted to grub-devel about this and the upstream maintainer pointed out that, even aside from multi- device problems, writing to btrfs from GRUB is fundamentally risky because:
* the same block may be used by multiple snapshots * every tree which uses a given block will contain its checksum, and so on recursively However, btrfs reserves space at the start for the boot loader. This space is more than GRUB needs to embed itself, and so we could use 1KB of it for an environment block. In any case, this is not a new problem that arose from using subvolumes, nor does it prevent booting (you get a spurious "Press any key to continue" prompt, but if you just ignore it it'll boot anyway). Thus I'm going to disregard it for the purposes of closing this bug, since I believe I've committed fixes for all the other problems, and track the environment block problem separately. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/712029 Title: ubiquity btrfs install fails to boot (grub rescue> prompt) -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
