bcachefs

Disk format change for snapshots

Added 2021-03-25 00:13:29 +0000 UTC

Turns out, there was a hiccup after all in the on disk format changes for snapshots: it turns out we were generating packed bkey formats where the snapshot field was too big, and this breaks the lookup code when we start using the snapshot field.

I just pushed out code to scan the btree for btree nodes that have these bad bkey formats and rewrite them, and flip a compatible feature bit once that's been done.

In order to get a smooth upgrade process, you'll need to upgrade your kernel and tools to the current latest master branch and mount or fsck once before I start pushing out snapshots. The patch in the snapshots branch that starts using the snapshots field will refuse to mount if that feature bit hasn't been set.