On 09/24/2013 09:23 PM, Ewan Milne wrote: > http://marc.info/?l=linux-scsi&m=133901769900806&w=2 > > Can we reconsider applying patch 4 in Mike's set? > The problem still exists, and there was never another > solution proposed as far as I can see. (I posted a > question about this a while back...) > > It is a big issue for people who happen to get a > KOBJ_CHANGE uevent while their iSCSI session happens > to be disconnected for some reason, because udev > will end up removing the /dev/by-xxx links when it > can't access the device. If there is no subsequent > uevent when the device is available again, the links > are never recreated. > Right. The original issue here is that we'll be getting a 'CHANGE' uevent for _EVERY_ device connected to that port / iscsi session. This has two potential issues: 1) We'll be pushing quite some events through udev, increasing the load at times when already is quite some I/O going on. 2) Currently SCSI devices only had to react to 'add' events for generating udev links, with 'change' events virtually non-existing. When we're not generating 'change' events for SCSI devices we absolutely have to audit / test the udev rules as they need to re-create _all_ device links etc on 'change', too. Otherwise we'll end up with the situation you've just described. Hence my original comment to send 'change' events for the session or rport, as this would result in only _one_ event thereby eliminating the event multiplication. It has the drawback that we won't get the automatic udev database update like we would be getting with the patch. But then we could easily achieve that by auditing the udev rules to fetch the required information off the udev database in case the device is not accessible. And as we have to audit the udev rules _anyway_ it feels like a better solution to me. (It certainly is for me, as I've already done this on the SUSE side; we've had a similar issue already :-) But if others feel strongly about this patch I won't object to it. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
