On Mon, Jan 15 2007, Thomas Gleixner wrote: > On Mon, 2007-01-15 at 09:08 +0100, Thomas Gleixner wrote: > > > Thomas saw something similar yesterday and he the partial results that > > > git.block (between rc2-mm1 and rc4-mm1) breaks certain disk drivers or > > > filesystems drivers. For me it worked fine, so it must be only on some > > > combinations. The changes to ll_rw_block.c look quite extensive. > > > > Yes. Jens Axboe confirmed yesterday that the plug changes broke RAID. > > I tracked this down and found two problems: > > - The new plug/unplug code does not check for underruns. That allows the > plug count (ioc->plugged) to become negative. This gets triggered from > various places. > > AFAICS this is intentional to avoid checks all over the place, but the > underflow check is missing. All we need to do is make sure, that in case > of ioc->plugged == 0 we return early and bug, if there is either a queue > plugged in or the plugged_list is not empty. > > Jens ?
It should not go negative, that would be a bug elsewhere. So it's interesting if it does, we should definitely put a WARN_ON() check in there for that. > - The raid1 code has no bitmap set in remount r/w. So the > pending_bio_list gets not processed for quite a time. The workaround is > to kick mddev->thread, so the list is processed. Not sure about that. > > Neil ? Super, thanks for that Thomas! I'll merge it in the plug branch. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
