On Wed, Apr 29 2015 at 9:24am -0400, Christoph Hellwig <hch@xxxxxx> wrote: > On Tue, Apr 28, 2015 at 05:54:57PM -0400, Mike Snitzer wrote: > > Turns out that after running hch's script, with multipathd having setup > > an mpath device ontop of tcm_loop, if I just do: > > > > tcm_loop --unload > > > > (tcm_loop appears to allow me to remove the devices out from underneath dm-multipath) > > That has nothing to do with tcm_loop. SCSI devices can get unregistered > any time, and we use refcountin to ensure the structures stay in place > forever. > > See my reply to Bart for what I suspect is the real issue. Already saw it, see my reply ;) Your fix only applies to he case where DM_MAPIO_REQUEUE is returned from map_request() due to .map_rq or .clone_and_map_rq failing. It doesn't apply to IO completion, example stack here: https://www.redhat.com/archives/dm-devel/2015-April/msg00157.html SCSI unregistering shouldn't nuke an in-flight request's queue (refcounting should work like you say) -- so my crashes are still unexplained, no? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
