> -----Original Message----- > From: Neil Brown [mailto:neilb@xxxxxxx] > Sent: Wednesday, December 08, 2010 3:30 AM > To: Labun, Marcin > Cc: linux-raid@xxxxxxxxxxxxxxx; Neubauer, Wojciech; Williams, Dan J; > Ciechanowski, Ed; Hawrylewicz Czarnowski, Przemyslaw; Czarnowska, Anna > Subject: Re: [PATCH 1/2] IMSM: Fix problem in mdmon monitor of using > removed disk from in imsm container. > <cut> > > int (*remove_from_super)(struct supertype *st, mdu_disk_info_t > *dinfo, > > int fd); > > The message prepared in remove_from_super is later processed > > by proceess_update handler in monitor thread. > > I don't like this. There is unnecessary complexity. > > adding a disk and removing a disk are very different sorts of > operations. > When adding a disk, you need to pass extra information about how the > disk > might be used - whether it is already part of the array, or if it is a > fresh > spare or whatever. > When removing a device there is none of that. Just remove the device. > > So when mdadm removes a device from a container it should > - get a lock so mdmon won't assign the device as spare > - check that the device is still a spare > - remove the device from the container > - unlock > - ping mdmon > > mdmon should notice that the device has gone and should update the > metadata > accordingly. Let me add a couple of comments and questions, so I can understand correctly what solution you want to get. My changes are in manager and monitor threads of mdmon. As you said, manager notices that a device has gone. So I added a call to new remove_disk_from_container in manage_container function (in manager thread). remove_disk_from_container is called for every device that has disappeared. The function remove_disk_from_container prepares an metadata update using handler functions and queues them using queue_metadata_update And that's all for manager thread. Now monitor thread of mdmon checks for metadata updates in update_queue global. Monitor walks update__queue list to call process_update handler. In IMSM process_update handler, I added code that removes spare disk descriptor from IMSM device list. Now my questions: - do you want to get rid of update_queue communication between manager and monitor for disk removal? - do you want to add non-metadata specific communication between manager and monitor? This would introduce generic disk_remove message that is passed from manager to monitor. The monitor would call metadata handler. - do you want the monitor thread to find out what disks has been removed and call metadata handlers? > > So you may still need a 'remove_from_super' method, but it will not > send a > metadata update request to mdmon. > Rather it will be run by mdmon when it notices the device is gone. > > It is probably appropriate to pass an mdu_disk_info_t or maybe just a > device > number. I don't think there is any need to pass an 'fd'. That's correct: fd is not needed. Thanks in advance, Marcin -- 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
