On 11/5/18 7:35 AM, Satheesh Rajendran wrote: > On Mon, Nov 05, 2018 at 08:51:57AM -0500, Mike Snitzer wrote: >> On Mon, Nov 05 2018 at 5:25am -0500, >> Michael Ellerman <m...@ellerman.id.au> wrote: >> >>> Linus Torvalds <torva...@linux-foundation.org> writes: >>> ... >>>> Mike Snitzer (1): >>>> device mapper updates >>> >>> Hi Mike, >>> >>> Replying here because I can't find the device-mapper pull or the patch >>> in question on LKML. I guess I should be subscribed to dm-devel. >>> >>> We have a box that doesn't boot any more, bisect points at one of: >>> >>> cef6f55a9fb4 Mike Snitzer dm table: require that request-based DM >>> be layered on blk-mq devices >>> 953923c09fe8 Mike Snitzer dm: rename DM_TYPE_MQ_REQUEST_BASED to >>> DM_TYPE_REQUEST_BASED >>> 6a23e05c2fe3 Jens Axboe dm: remove legacy request-based IO path >>> >>> >>> It's a Power8 system running Rawhide, it does have multipath, but I'm >>> told it was setup by the Fedora installer, ie. nothing fancy. >>> >>> The symptom is the system can't find its root filesystem and drops into >>> the initramfs shell. The dmesg includes a bunch of errors like below: >>> >>> [ 43.263460] localhost multipathd[1344]: sdb: fail to get serial >>> [ 43.268762] localhost multipathd[1344]: mpatha: failed in domap for >>> addition of new path sdb >>> [ 43.268762] localhost multipathd[1344]: uevent trigger error >>> [ 43.282065] localhost kernel: device-mapper: table: table load >>> rejected: not all devices are blk-mq request-stackable >> ... >>> >>> Any ideas what's going wrong here? >> >> "table load rejected: not all devices are blk-mq request-stackable" >> speaks to the fact that you aren't using blk-mq for scsi (aka scsi-mq). >> >> You need to use scsi_mod.use_blk_mq=Y on the kernel commandline (or set >> CONFIG_SCSI_MQ_DEFAULT in your kernel config) > > Thanks Mike!, above solution worked and the system booted fine now:-)
This quirk will go away for the next kernel, fwiw, since the non-mq path for SCSI will be dropped as well. -- Jens Axboe