On Tue, Oct 02, 2018 at 11:02:50PM +0200, Martin Wilck wrote: > Hi Ben, Christophe, > > I found a problem with this old patch series of mine. > > while I am still pondering about your latest series, it occured to me > that my patch "get_uid: don't quit prematurely without udev" is against > the spirit of your "retrigger uevents to try and get the uid through > udev" patch from 2016 (688aa22b). > > "get_uid: don't quit prematurely without udev" has been merged a while > ago (08d42ee6). Should it be reverted?? > > Pro: the patch is against the "udev first" philosophy and subverts the > retrigger logic. > Con: with the patch, we'll be able to retrieve WWIDs more quickly in > some situations, as we don't have to wait for udev. > > Either way (but more likely with my patch), it may happen that we > retrieve a WWID from sysfs or elsewhere first, and from udev later. > These WWIDs may not necessarily match, and a "WWID changed" problem may > occur. > > Please tell me what you think. I'm having a hard time seeing how get_uid() could get called on a path without a udev device attached in multipathd. It can happen because of update_paths() in multipath, for paths that don't get discovered when searching for paths, but do belong to an existing multipath device. I don't think you patch will hurt anything here. So, unless I'm missing some code path in multipathd, I don't see a problem with this patch. In fact, we should probably make scsi_uid_fallback() skip (or at least always pass) the retrigger check if we aren't in the daemon, so we always try the failback when we run multipath. -Ben > > Martin > > > -- > Dr. Martin Wilck <mwilck@xxxxxxxx>, Tel. +49 (0)911 74053 2107 > SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton > HRB 21284 (AG Nürnberg) > -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
