Messages in this thread | | | Subject | Re: [RFC 00/11] DAX fsynx/msync support | From | Jens Axboe <> | Date | Thu, 5 Nov 2015 13:54:19 -0700 |
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On 11/05/2015 01:33 AM, Dave Chinner wrote: >> Des xfs rely on this model for correctness? If so, I'd say we've got a >> problem > > No, it doesn't. The XFS integrity model doesn't trust the IO layers > to tell the truth about IO ordering and completion or for it's > developers to fully understand how IO layer ordering works. :P
That's good, because the storage developers simplified the model so that fs developers would be able to get and use it.
> i.e. we wait for full completions of all dependent IO before issuing > flushes or log writes that use REQ_FLUSH|REQ_FUA semantics to ensure > the dependent IOs are fully caught by the cache flushes...
... which is what you are supposed to do, that's how it works.
-- Jens Axboe
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