Re: Proposal: B_ARRIER (addresses wapbl performance?)

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> For the journal we only want "written to stable storage before
> written the meta data blocks back".  Isn't that what ordered tags are
> supposed to provide?

Is it?  I'd expect them to give that only when combined with FUA.
Without that, I'd expect them to give "written to the cache before the
metadata blocks are", with flushing from the cache to the underlying
medium being a separate issue.

It seems to me you want FUA to make sure the bits hit the platters and
you want ordered tags for the ordering constraints - neither looks
sufficient for journaling without the other.  Or Am I Missing Something?

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