"lsluns" does not display ds8k lun information and unable to activate ds8k storage luns in host

[bugproxy]

== Comment: #2 - Steffen Maier - 2016-08-01 09:54:09 ==
While

LTC bug 139096 - LP1567602 : FCP devices are not detected correctly nor deterministically

did successfully fix the attachment of "regular" LUNs of (peripheral device) type disk,
it seems the attachment of the (report luns) WLUN 0xc101000000000000 (49409) still shows issues with the ALUA device handler:

[ 105.049479] scsi 0:0:7:49409: Well-known LUN IBM 2107900 .470 PQ: 0 ANSI: 5
[ 105.050109] scsi 0:0:7:49409: alua: disable for non-disk devices
[ 105.050112] scsi 0:0:7:49409: alua: Attach failed (-22)
[ 105.050114] scsi 0:0:7:49409: failed to add device handler: -22

After this failed attempt to attach such LUN (here triggered by the "lsluns" tool from s390-tools to discover LUNs from out of user space), the corresponding SCSI device is INvisible from user space, but still exists in-kernel in some broken state.

In our case here, the attachment should have been successful
(or the scsi_device been unregistered completely in maybe other cases).

On the next attempt to run lsluns against the same target remote port and thus the same WLUN SCSI device, we get the following kernel warning as a follow-on error:

[ 572.079588] scsi 0:0:7:49409: Well-known LUN IBM 2107900 .470 PQ: 0 ANSI: 5
[ 572.080354] sysfs: cannot create duplicate filename '/bus/scsi/devices/0:0:7:49409'
[ 572.080380] ------------[ cut here ]------------
[ 572.080381] WARNING: at /build/linux-0ECIDW/linux-4.4.0/fs/sysfs/dir.c:31
[ 572.080381] Modules linked in: qeth_l3 chsc_sch eadm_sch qeth ccwgroup ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi nfsd auth_rpcgss nfs_acl lockd grace sunrpc btrfs zlib_deflate raid10 raid456 async_memcpy async_raid6_recov async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 linear dm_round_robin ghash_s390 prng aes_s390 des_s390 des_generic sha512_s390 sha256_s390 sha1_s390 sha_common dasd_eckd_mod dasd_mod zfcp qdio scsi_transport_fc scsi_dh_emc scsi_dh_rdac scsi_dh_alua dm_multipath
[ 572.080404] CPU: 1 PID: 8494 Comm: sh Not tainted 4.4.0-31-generic #50-Ubuntu
[ 572.080405] task: 00000001d7740af0 ti: 00000001d8144000 task.ti: 00000001d8144000
[ 572.080406] Krnl PSW : 0704c00180000000 00000000003a35fc (sysfs_warn_dup+0x7c/0x98)
[ 572.080415] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 EA:3
               Krnl GPRS: 0000000000cf7034 0000000000000006 0000000000000047 0000000000000000
[ 572.080417] 00000000003a35f8 00000000000002c6 00000001da805400 00000001d8f2f178
[ 572.080417] 0000000000c1d0e0 00000001e8cd3ab8 0000000000000001 00000001e8cd3ab8
[ 572.080418] 00000001d8cac4b0 000000007b7c8000 00000000003a35f8 00000001d81479b8
[ 572.080425] Krnl Code: 00000000003a35ec: c020002f33f3 larl %r2,989dd2
                          00000000003a35f2: c0e5fff6bf0b brasl %r14,27b408
                         #00000000003a35f8: a7f40001 brc 15,3a35fa
                         >00000000003a35fc: b904002d lgr %r2,%r13
                          00000000003a3600: ebbff0a00004 lmg %r11,%r15,160(%r15)
                          00000000003a3606: c0f4fffa5999 brcl 15,2ee938
                          00000000003a360c: a7390000 lghi %r3,0
                          00000000003a3610: a7f4ffec brc 15,3a35e8
[ 572.080438] Call Trace:
[ 572.080440] ([<00000000003a35f8>] sysfs_warn_dup+0x78/0x98)
[ 572.080443] [<00000000003a3b10>] sysfs_do_create_link_sd.isra.0+0xf8/0x108
[ 572.080447] [<00000000005c4004>] bus_add_device+0x13c/0x230
[ 572.080448] [<00000000005c1718>] device_add+0x398/0x680
[ 572.080453] [<00000000005f79bc>] scsi_sysfs_add_sdev+0xcc/0x2a8
[ 572.080456] [<00000000005f4198>] scsi_probe_and_add_lun+0xcc0/0xe18
[ 572.080457] [<00000000005f4be2>] __scsi_scan_target+0xba/0x268
[ 572.080458] [<00000000005f4e92>] scsi_scan_target+0x102/0x120
[ 572.080468] [<000003ff800765f6>] zfcp_unit_scsi_scan+0x7e/0x90 [zfcp]
[ 572.080471] [<000003ff80076948>] zfcp_unit_add+0x168/0x1f0 [zfcp]
[ 572.080474] [<000003ff80075564>] zfcp_sysfs_unit_add_store+0x54/0x70 [zfcp]
[ 572.080476] [<00000000003a1d7a>] kernfs_fop_write+0x13a/0x190
[ 572.080480] [<000000000030fc94>] vfs_write+0x94/0x1a0
[ 572.080482] [<00000000003109a6>] SyS_write+0x66/0xd8
[ 572.080484] [<00000000007b844e>] system_call+0xd6/0x264
[ 572.080485] [<000003ff9fc5f6e8>] 0x3ff9fc5f6e8
[ 572.080486] Last Breaking-Event-Address:
[ 572.080487] [<00000000003a35f8>] sysfs_warn_dup+0x78/0x98
[ 572.080487] ---[ end trace 622dfcc1a25e342e ]---
[ 572.080504] scsi 0:0:7:49409: failed to add device: -17

[Frank Heimes (fheimes)]

Due to the fact that this issue is lslun related and lslun belongs to the s390-tools set:
https://www.ibm.com/developerworks/linux/linux390/s390-tools-overview.html
the IBM LTC needs to have a look at that.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2016-08-24 09:12 EDT-------
As I wrote in my previous analysis comment, this is a kernel bug. lsluns just suffers from this kernel bug as a follow-on error and there is nothing lsluns can do.

[Dimitri John Ledkov (xnox)]

Have patches to resolve this issue been created and contributed by IBM to linux kernel upstream? Do you have commit ids please?

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Ubuntu on IBM z Systems because there has been no activity for 60 days.]