On Thu, 2024-11-07 at 12:43 -0500, Benjamin Marzinski wrote: > On Thu, Nov 07, 2024 at 01:20:09PM +0100, Martin Wilck wrote: > > > > Thinking about it, I believe we should actually accept devices that > > have an mpath UUID and an empty table, and add them to our mpvec. > > We > > should treat them like devices that have a multipath target but no > > path > > devices. If any matching paths become available, the map will be > > reloaded and the issue will be fixed. IMO, this is less prone to > > race > > conditions than trying to delete and re-add the devices. > > I'm not sure off the top of my head how easy it will be to handle > devices with no dm table at all, but I'll take a look into this. I tried this on a system with 0.9.9 yesterday. 0.9.9 will not add the map into the mpvec. But in coalesce_paths(), it will just reload the map: multipathd[3198]: 360014053cdf4a9b80de42ab96c74f4ef: set ACT_CREATE (map does not exist) multipathd[3198]: 360014053cdf4a9b80de42ab96c74f4ef: map already present multipathd[3198]: 360014053cdf4a9b80de42ab96c74f4ef: reload [0 41943040 multipath 1 queue_if_no_path 1 alua 2 1 service-time 0 1 1 8:16 1 serv> Note that it first says "map does not exist", and then sees it present (with no table). The reload works without issues though, if the map is empty. If, on the contrary, the map is not empty but contains another incompatible target (I tried this with a trivial linear mapping), the reload operation will fail: multipathd[1347]: 360014053cdf4a9b80de42ab96c74f4ef: set ACT_CREATE (map does not exist) multipathd[1347]: 360014053cdf4a9b80de42ab96c74f4ef: map already present multipathd[1347]: 360014053cdf4a9b80de42ab96c74f4ef: reload [0 41943040 multipath 1 queue_if_no_path 1 alua 2 1 service-time 0 1 1 8:16 1 serv> kernel: device-mapper: ioctl: can't change device type (old=1 vs new=2) after initial table load. multipathd[1347]: libdevmapper: ioctl/libdm-iface.c(1998): device-mapper: reload ioctl on 360014053cdf4a9b80de42ab96c74f4ef failed: Invalid argument multipathd[1347]: dm_addmap: libdm task=1 error: Invalid argument multipathd[1347]: 360014053cdf4a9b80de42ab96c74f4ef: domap (0) failure for create/reload map multipathd[1347]: 360014053cdf4a9b80de42ab96c74f4ef: removing map Regards Martin
