Am 20.10.2014 um 17:40 schrieb Artem Bityutskiy: > On Mon, 2014-10-20 at 17:17 +0200, Richard Weinberger wrote: >>> That's just fastmap code not doing the right thing. We should not touch >>> the work queue directly at all. What we _should_ do instead is to make >>> it empty by asking the subsystem which manages it to flush it. >>> >>> 1. Lock the work queue to prevent anyone from submitting new jobs while >>> we are in process of writing the fastmap. >>> 2. Flush all works >>> 3. do all the fastmap write stuff >>> 4. Unlock >> >> Are you sure? Flushing all works before every fastmap write will slow UBI >> down. >> The fastmap write is not cheap. The goal should be to make it faster. > > Yes, you are right. So instead, we wanna "freeze" it, and save all PEBs > the jobs in fastmap too. > > Why 'ubi_write_fastmap()' only cares about the erase jobs, and saves the > PEBs from the job as "must be erased". > > What about the "move" jobs?
There are no move jobs. Do you mean ubi->move_from/to used in wear_leveling_worker()? How could it happen that a fastmap is written between these? IIRC everything is done under wl_lock. And the PEBs used have to go through the pool. > Also, say, PEB X is in the work queue waiting for erasure. Fastmap comes > along and saves it as "must be erased" in the fastmap. Fastmap finishes > its job, PEB X gets erased, and I write my data there, so PEB X is > referred to by LEB Y. Now I have power cut. Then I attach the flash > again. Surely it is not that fastmap just erases PEB X and I lose the > contents of LEB Y? This cannot happen. If X is erased you cannot write data do it. I must first go thought the pool and the pool is scanned while attaching. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
