On Fri, 17 Feb 2017, shiva rkreddy wrote:

> Hi Eric:
> 
> Kernel version: 4.2.0.42
> 
> It was 3.13 (Ubuntu Trusty) kernel that was upgraded to Ubuntu
> "linux-generic-lts-wily". This upgrade made the kernel version to
> 4.2.0.42.
> The devices were created after kernel upgrade to 4.2.0.42.

I'm not sure what Ubuntu has patched in, and 4.2 isn't a supported 
upstream kernel.  Try 4.1.38 or 4.4.49.

--
Eric Wheeler


> 
> I can reproduce and provide more details if needed.
> 
> This was the whole backtrace from dmesg:
> 
> ===
> [ 53.752177] bcache: register_cache() registered cache device nvme0n1p17
> [ 58.641878] bcache: register_bdev() registered backing device sdj
> [ 253.701153] INFO: task bcache_allocato:496 blocked for more than 120 seconds.
> [ 253.953639] bcache_allocato D ffff88085fe16640 0 496 2 0x00000000
> [ 253.953670] [<ffffffffc01311e3>] bch_bucket_alloc+0x163/0x320 [bcache]
> [ 253.953682] [<ffffffffc014fa36>] ? bch_crc64+0x36/0x50 [bcache]
> [ 253.953689] [<ffffffffc0146de4>] bch_prio_write+0x184/0x310 [bcache]
> [ 253.953693] [<ffffffffc0131019>] bch_allocator_thread+0x3d9/0x440 [bcache]
> [ 253.953699] [<ffffffffc0130c40>] ? invalidate_buckets+0x920/0x920 [bcache]
> [ 253.953716] INFO: task bcache-register:525 blocked for more than 120 seconds.
> [ 254.206187] bcache-register D ffff88085fe16640 0 525 1 0x00000004
> [ 254.206202] [<ffffffffc01311e3>] bch_bucket_alloc+0x163/0x320 [bcache]
> [ 254.206208] [<ffffffffc013152c>] __bch_bucket_alloc_set+0xec/0x140 [bcache]
> [ 254.206213] [<ffffffffc01315ce>] bch_bucket_alloc_set+0x4e/0x70 [bcache]
> [ 254.206218] [<ffffffffc0145866>] __uuid_write+0x46/0xe0 [bcache]
> [ 254.206223] [<ffffffffc0146806>] bch_uuid_write+0x16/0x40 [bcache]
> [ 254.206228] [<ffffffffc0147493>] bch_cached_dev_attach+0x153/0x490 [bcache]
> [ 254.206249] [<ffffffffc0149645>] register_bcache+0xa25/0x13b0 [bcache]
> [ 254.206317] INFO: task bcache-register:527 blocked for more than 120 seconds.
> [ 254.458788] bcache-register D ffff88105f456640 0 527 1 0x00000004
> [ 254.458812] [<ffffffffc0148e5e>] register_bcache+0x23e/0x13b0 [bcache]
> [ 254.458832] INFO: task bcache-register:548 blocked for more than 120 seconds.
> [ 254.711311] bcache-register D ffff88105f456640 0 548 1 0x00000004
> ===
> 
> Thanks
> Shiva
> 
> On Fri, Feb 17, 2017 at 5:57 PM, Eric Wheeler <bcache@lists.ewheeler.net> wrote:
> > Hi Shiva,
> >
> > What kernel version?
> >
> > Also, see if you can paste the trace without wrapping and include the
> > whole backtrace including kernel version and line numbers if any.
> >
> > --
> > Eric Wheeler
> >
> > On Fri, 17 Feb 2017, shiva rkreddy wrote:
> >
> >> Greetings to all!
> >>
> >> I'm experimenting bcache with sas disks as backing devices and nvme as
> >> cache. The backing devices are used as ceph osd mount points.
> >> I was able to make them part of ceph cluster and have the ceph mount
> >> points added to fstab using the bcache uuid.
> >>
> >> These bcache backing devices are disappearing after rebooting the host
> >> that has these devices. dmesg shows, bcache_allocto blocked and later
> >> bcache-register blocked.
> >> bcache cache device is registered successfully though.
> >>
> >> Digged the mailing list and couldn't find consumable information. Did
> >> anyone encounter this problem ? Any thoughts on troubleshooting ..
> >>
> >> Appreciate your help!
> >>
> >> Here is excerpt from dmesg:
> >>
> >> [   53.752029] bcache: bch_journal_replay() journal replay done, 2173
> >> keys in 153 entries, seq 331031
> >>                                    │
> >>
> >> [   53.752177] bcache: register_cache() registered cache device
> >> nvme0n1p17
> >>                                          │
> >>
> >> [   58.641878] bcache: register_bdev() registered backing device sdj
> >>
> >>                                   │
> >>
> >> [  253.701153] INFO: task bcache_allocato:496 blocked for more than
> >> 120 seconds.
> >>                                      │
> >>
> >> [  253.953639] bcache_allocato D ffff88085fe16640     0   496      2
> >> 0x00000000
> >>                                     │
> >>
> >> [  253.953670]  [<ffffffffc01311e3>] bch_bucket_alloc+0x163/0x320
> >> [bcache]
> >>                                        │
> >>
> >> [  253.953682]  [<ffffffffc014fa36>] ? bch_crc64+0x36/0x50 [bcache]
> >>
> >>                                   │
> >>
> >> [  253.953689]  [<ffffffffc0146de4>] bch_prio_write+0x184/0x310
> >> [bcache]
> >>                                          │
> >>
> >> [  253.953693]  [<ffffffffc0131019>] bch_allocator_thread+0x3d9/0x440
> >> [bcache]
> >>                                    │
> >>
> >> [  253.953699]  [<ffffffffc0130c40>] ? invalidate_buckets+0x920/0x920
> >> [bcache]
> >>                                    │
> >>
> >> [  253.953716] INFO: task bcache-register:525 blocked for more than
> >> 120 seconds.
> >>                                      │
> >>
> >> [  254.206187] bcache-register D ffff88085fe16640     0   525      1
> >> 0x00000004
> >>                                     │
> >>
> >> [  254.206202]  [<ffffffffc01311e3>] bch_bucket_alloc+0x163/0x320
> >> [bcache]
> >>                                        │
> >>
> >> [  254.206208]  [<ffffffffc013152c>] __bch_bucket_alloc_set+0xec/0x140
> >> [bcache]
> >>                                   │
> >>
> >> [  254.206213]  [<ffffffffc01315ce>] bch_bucket_alloc_set+0x4e/0x70
> >> [bcache]
> >>                                      │
> >>
> >> [  254.206218]  [<ffffffffc0145866>] __uuid_write+0x46/0xe0 [bcache]
> >>
> >>                                   │
> >>
> >> [  254.206223]  [<ffffffffc0146806>] bch_uuid_write+0x16/0x40 [bcache]
> >>
> >>                                   │
> >>
> >> [  254.206228]  [<ffffffffc0147493>] bch_cached_dev_attach+0x153/0x490
> >> [bcache]
> >>                                   │
> >>
> >> [  254.206249]  [<ffffffffc0149645>] register_bcache+0xa25/0x13b0
> >> [bcache]
> >>                                        │
> >>
> >> [  254.206317] INFO: task bcache-register:527 blocked for more than
> >> 120 seconds.
> >>                                      │
> >>
> >> [  254.458788] bcache-register D ffff88105f456640     0   527      1
> >> 0x00000004
> >>                                     │
> >>
> >> [  254.458812]  [<ffffffffc0148e5e>] register_bcache+0x23e/0x13b0
> >> [bcache]
> >>                                        │
> >>
> >> [  254.458832] INFO: task bcache-register:548 blocked for more than
> >> 120 seconds.
> >>                                      │
> >>
> >> [  254.711311] bcache-register D ffff88105f456640     0   548      1 0x00000004
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe linux-bcache" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >>
>