Ackchually, the journal is not a WAL (a journal is a log of intended and completed actions, while the WAL actually stores the data before committing it to the data store, it's more advanced and can recover all data ).
But yeah, I agree that is what the journal is for. However, I don't know if the journal in "modern" filesystems works the same when a drive reconnects than when the power is cut out (the OS still being alive and all in the first case).
I would expect that it must: the OS cannot assume that the newly connected drive wasn't altered by another system in the meantime. (Or that it's the same FS, even.)
(although I grant that, a.) the FS probably has a UUID that idents it, and b.) it's only gone for a few ms — but those aren't things that, reasonably, the OS is going to look at to go "eh, we don't need to recover this newly attached disk".)
(I'm not sure I'm still grokking the differences between a WAL & a journal, to you.)
But yeah, I agree that is what the journal is for. However, I don't know if the journal in "modern" filesystems works the same when a drive reconnects than when the power is cut out (the OS still being alive and all in the first case).