Heinz Mauelshagen [mauelshagen@xxxxxxxxxx] wrote: > > > RH_MAYBE_DIRTY sounds superfluous at first glance, because when all writes > > > to a region drained, we can set RH_CLEAN_CANDIDATE, run the sync() and check > > > if that state persists in order to trigger the dirty log update. If I understand your above description: a region's state is set to RH_DIRTY when an I/O is scheduled in the region and is set to RH_CLEAN_CANDIDATE when all I/O is completed. In other words, a region's state is RH_CLEAN_CANDIDATE when there is no pending I/O to that region. Did I get it right so far? Then we invoke sync(). Now, if the region's state is RH_CLEAN_CANDIDATE, you set the region's state to RH_CLEAN. If the region's state is anything other than RH_CLEAN_CANDIDATE, you don't do anything. Am I correct? > > I don't think the state RH_MAYBE_DIRTY is superfluous. If the region > > state is RH_CLEAN_CANDIDATE after the sync(), that means no 'write' > > happened since we set RH_CLEAN_CANDIDATE. If there was any write, the > > region state would be 'RH_DIRTY' or 'RH_MAYBE_DIRTY'. > > Hrm, sound like a contradiction in your statement. > Either it stays RH_CLEAN_CANDIDATE because of no writes *or* > it's state-changing to RH_DIRTY, no ? The state would be RH_CLEAN_CANDIDATE if there were ***NO*** writes as part of sync(). The next statement only describes what would happen if there were any writes as part of sync(). --Malahal. PS: Any comments from the original submitter if he thinks the state is really superfluous? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
