037331ddbd
the g_journal level needs to check whether it is holding a newer copy of the block than that which exists on the disk. If so, it needs to return its copy. If not, it should pass the request down to the disk to fulfill. It currently considers six queues: 0) delayed queue, 1) unsent (current queue), 2) in-flight to the journal (flush queue), 3) active journal (active queue), 4) inactive journal (inactive queue), and 5) inflight to the disk (copy queue). Checking on two of these queues is unnecessary: 0) The delayed requests should not be used for reads because they have not yet been entered into the journal, so their value should reflect the disk contents, not the future contents that are not yet committed. 2) Because all the bio's in the flush queue are also found on the active queue, there is no need to inspect the flush queue for reads since they will be found when searching the active queue. Submitted by: Dr. Andreas Longwitz <longwitz@incore.de> Discussed with: kib MFC after: 1 week
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