On Tue, 15 Jul 2008 08:09:53 -0400 (EDT) Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote: > >> BTW. what should the block device driver do when it receives a mapping > >> error? (if it aborts the request and it was write request, there will be > >> data corruption). > > > > I'm not sure how a aborted request can corrupt data on disk. > > Writes are done by an async daemon and no one checks for their completion > status. If there are three writes to directory, inode table and inode > bitmap and one of these writes fail, there's no code to undo the other > two. So the filesystem will be corrupted on write failure. Are you talking about file system metadata corruption? If your logic is correct, we hit the corruption every time a FC cable (switch, or whatever) has a problem. Fortunately, we don't. modern file systems can handle that. > >> Is it even legal to return IOMMU error in case where no > >> real hardware error or overflow happened? > > > > Of course, it's legal. It's a common event like kinda OOM. It's very > > possible with old IOMMUs that have the small I/O space. A SCSI driver > > retries a failed request later. But note that some drivers are still > > not able to handle that. > > > > http://marc.info/?l=linux-kernel&m=121300637114672&w=2 > > So should it return SCSI_MLQUEUE_HOST_BUSY? Or something other? > > Unfortunatelly, many of the drivers contain BUG_ON or no check at all. Yeah, many of the old scsi drivers contatinas BUG_ON. They are not likely to be used with IOMMUs. We don't care about them much. The recent scsi drivers can handle this. -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
