On Wed, 2019-01-30 at 07:58 -0500, Austin S. Hemmelgarn wrote: > Running dm-integrity without a journal is roughly equivalent to > using > the nobarrier mount option (the journal is used to provide the same > guarantees that barriers do). IOW, don't do this unless you are > willing > to lose the whole volume. That sounds a bit strange to me. My understanding was that the idea of being able to disable the journal of dm-integrity was just to avoid any double work, if equivalent guarantees are already given by higher levels. If btrfs is by itself already safe (by using barriers), then I'd have expected that not transaction is committed, unless it got through all lower layers... so either everything works well on the dm-integrity base (and thus no journal is needed)... or it fails there... but then btrfs would already safe by it's own means (barriers + CoW)? Cheers, Chris.
