On Thu, 9 Jul 2015 21:52:43 -0700 Shaohua Li <shli@xxxxxx> wrote: > On Fri, Jul 10, 2015 at 02:36:56PM +1000, NeilBrown wrote: > > On Thu, 9 Jul 2015 21:08:49 -0700 Shaohua Li <shli@xxxxxx> wrote: > > > > There is also the issue of what action commits a previous transaction. > > I'm not sure what you had. I'm suggesting that each metadata block > > commits previous transactions. Is that a close-enough match to what > > you had? > > What did you mean about a transaction? In my implementation, metadata > block and followed stripe data/parity consist of an io unit. io units can > be finished out of order. but if io unit has flush request (the data has > flush/flush bio or metadata is a flush block), the io unit can only > start after all previous io units and disk cache flush finish. Such io > unit is strictly ordered. The log patch describes this behavior. Does it > match? Yes, a "transaction" is an "io unit". The flushing is the same. I just couldn't remember how, when reading the log on restart, you determined if a given "io unit" was reliably consistent, or whether it should be ignored (having possibly only partially been written). Thanks, NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
