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response
commit fdb7cee3b9e3c561502e58137a837341f10cbf8b upstream.
At the default trace level, we only trace unsuccessful events including
FSF responses.
zfcp_dbf_hba_fsf_response() only used protocol status and FSF status to
decide on an unsuccessful response. However, this is only one of multiple
possible sources determining a failed struct zfcp_fsf_req.
An FSF request can also "fail" if its response runs into an ERP timeout
or if it gets dismissed because a higher level recovery was triggered
[trace tags "erscf_1" or "erscf_2" in zfcp_erp_strategy_check_fsfreq()].
FSF requests with ERP timeout are:
FSF_QTCB_EXCHANGE_CONFIG_DATA, FSF_QTCB_EXCHANGE_PORT_DATA,
FSF_QTCB_OPEN_PORT_WITH_DID or FSF_QTCB_CLOSE_PORT or
FSF_QTCB_CLOSE_PHYSICAL_PORT for target ports,
FSF_QTCB_OPEN_LUN, FSF_QTCB_CLOSE_LUN.
One example is slow queue processing which can cause follow-on errors,
e.g. FSF_PORT_ALREADY_OPEN after FSF_QTCB_OPEN_PORT_WITH_DID timed out.
In order to see the root cause, we need to see late responses even if the
channel presented them successfully with FSF_PROT_GOOD and FSF_GOOD.
Example trace records formatted with zfcpdbf from the s390-tools package:
Timestamp : ...
Area : REC
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : ...
Record ID : 1
Tag : fcegpf1
LUN : 0xffffffffffffffff
WWPN : 0x<WWPN>
D_ID : 0x00<D_ID>
Adapter status : 0x5400050b
Port status : 0x41200000
LUN status : 0x00000000
Ready count : 0x00000001
Running count : 0x...
ERP want : 0x02 ZFCP_ERP_ACTION_REOPEN_PORT
ERP need : 0x02 ZFCP_ERP_ACTION_REOPEN_PORT
|
Timestamp : ... 30 seconds later
Area : REC
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : ...
Record ID : 2
Tag : erscf_2
LUN : 0xffffffffffffffff
WWPN : 0x<WWPN>
D_ID : 0x00<D_ID>
Adapter status : 0x5400050b
Port status : 0x41200000
LUN status : 0x00000000
Request ID : 0x<request_ID>
ERP status : 0x10000000 ZFCP_STATUS_ERP_TIMEDOUT
ERP step : 0x0800 ZFCP_ERP_STEP_PORT_OPENING
ERP action : 0x02 ZFCP_ERP_ACTION_REOPEN_PORT
ERP count : 0x00
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Timestamp : ... later than previous record
Area : HBA
Subarea : 00
Level : 5 > default level => 3 <= default level
Exception : -
CPU ID : 00
Caller : ...
Record ID : 1
Tag : fs_qtcb => fs_rerr
Request ID : 0x<request_ID>
Request status : 0x00001010 ZFCP_STATUS_FSFREQ_DISMISSED
| ZFCP_STATUS_FSFREQ_CLEANUP
FSF cmnd : 0x00000005
FSF sequence no: 0x...
FSF issued : ... > 30 seconds ago
FSF stat : 0x00000000 FSF_GOOD
FSF stat qual : 00000000 00000000 00000000 00000000
Prot stat : 0x00000001 FSF_PROT_GOOD
Prot stat qual : 00000000 00000000 00000000 00000000
Port handle : 0x...
LUN handle : 0x00000000
QTCB log length: ...
QTCB log info : ...
In case of problems detecting that new responses are waiting on the input
queue, we sooner or later trigger adapter recovery due to an FSF request
timeout (trace tag "fsrth_1").
FSF requests with FSF request timeout are:
typically FSF_QTCB_ABORT_FCP_CMND; but theoretically also
FSF_QTCB_EXCHANGE_CONFIG_DATA or FSF_QTCB_EXCHANGE_PORT_DATA via sysfs,
FSF_QTCB_OPEN_PORT_WITH_DID or FSF_QTCB_CLOSE_PORT for WKA ports,
FSF_QTCB_FCP_CMND for task management function (LUN / target reset).
One or more pending requests can meanwhile have FSF_PROT_GOOD and FSF_GOOD
because the channel filled in the response via DMA into the request's QTCB.
In a theroretical case, inject code can create an erroneous FSF request
on purpose. If data router is enabled, it uses deferred error reporting.
A READ SCSI command can succeed with FSF_PROT_GOOD, FSF_GOOD, and
SAM_STAT_GOOD. But on writing the read data to host memory via DMA,
it can still fail, e.g. if an intentionally wrong scatter list does not
provide enough space. Rather than getting an unsuccessful response,
we get a QDIO activate check which in turn triggers adapter recovery.
One or more pending requests can meanwhile have FSF_PROT_GOOD and FSF_GOOD
because the channel filled in the response via DMA into the request's QTCB.
Example trace records formatted with zfcpdbf from the s390-tools package:
Timestamp : ...
Area : HBA
Subarea : 00
Level : 6 > default level => 3 <= default level
Exception : -
CPU ID : ..
Caller : ...
Record ID : 1
Tag : fs_norm => fs_rerr
Request ID : 0x<request_ID2>
Request status : 0x00001010 ZFCP_STATUS_FSFREQ_DISMISSED
| ZFCP_STATUS_FSFREQ_CLEANUP
FSF cmnd : 0x00000001
FSF sequence no: 0x...
FSF issued : ...
FSF stat : 0x00000000 FSF_GOOD
FSF stat qual : 00000000 00000000 00000000 00000000
Prot stat : 0x00000001 FSF_PROT_GOOD
Prot stat qual : ........ ........ 00000000 00000000
Port handle : 0x...
LUN handle : 0x...
|
Timestamp : ...
Area : SCSI
Subarea : 00
Level : 3
Exception : -
CPU ID : ..
Caller : ...
Record ID : 1
Tag : rsl_err
Request ID : 0x<request_ID2>
SCSI ID : 0x...
SCSI LUN : 0x...
SCSI result : 0x000e0000 DID_TRANSPORT_DISRUPTED
SCSI retries : 0x00
SCSI allowed : 0x05
SCSI scribble : 0x<request_ID2>
SCSI opcode : 28... Read(10)
FCP rsp inf cod: 0x00
FCP rsp IU : 00000000 00000000 00000000 00000000
^^ SAM_STAT_GOOD
00000000 00000000
Only with luck in both above cases, we could see a follow-on trace record
of an unsuccesful event following a successful but late FSF response with
FSF_PROT_GOOD and FSF_GOOD. Typically this was the case for I/O requests
resulting in a SCSI trace record "rsl_err" with DID_TRANSPORT_DISRUPTED
[On ZFCP_STATUS_FSFREQ_DISMISSED, zfcp_fsf_protstatus_eval() sets
ZFCP_STATUS_FSFREQ_ERROR seen by the request handler functions as failure].
However, the reason for this follow-on trace was invisible because the
corresponding HBA trace record was missing at the default trace level
(by default hidden records with tags "fs_norm", "fs_qtcb", or "fs_open").
On adapter recovery, after we had shut down the QDIO queues, we perform
unsuccessful pseudo completions with flag ZFCP_STATUS_FSFREQ_DISMISSED
for each pending FSF request in zfcp_fsf_req_dismiss_all().
In order to find the root cause, we need to see all pseudo responses even
if the channel presented them successfully with FSF_PROT_GOOD and FSF_GOOD.
Therefore, check zfcp_fsf_req.status for ZFCP_STATUS_FSFREQ_DISMISSED
or ZFCP_STATUS_FSFREQ_ERROR and trace with a new tag "fs_rerr".
It does not matter that there are numerous places which set
ZFCP_STATUS_FSFREQ_ERROR after the location where we trace an FSF response
early. These cases are based on protocol status != FSF_PROT_GOOD or
== FSF_PROT_FSF_STATUS_PRESENTED and are thus already traced by default
as trace tag "fs_perr" or "fs_ferr" respectively.
NB: The trace record with tag "fssrh_1" for status read buffers on dismiss
all remains. zfcp_fsf_req_complete() handles this and returns early.
All other FSF request types are handled separately and as described above.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: 8a36e4532ea1 ("[SCSI] zfcp: enhancement of zfcp debug features")
Fixes: 2e261af84cdb ("[SCSI] zfcp: Only collect FSF/HBA debug data for matching trace levels")
Cc: <stable@vger.kernel.org> #2.6.38+
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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commit 56d23ed7adf3974f10e91b643bd230e9c65b5f79 upstream.
Since quite a while, Linux issues enough SCSI commands per scsi_device
which successfully return with FCP_RESID_UNDER, FSF_FCP_RSP_AVAILABLE,
and SAM_STAT_GOOD. This floods the HBA trace area and we cannot see
other and important HBA trace records long enough.
Therefore, do not trace HBA response errors for pure benign residual
under counts at the default trace level.
This excludes benign residual under count combined with other validity
bits set in FCP_RSP_IU, such as FCP_SNS_LEN_VAL. For all those other
cases, we still do want to see both the HBA record and the corresponding
SCSI record by default.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: a54ca0f62f95 ("[SCSI] zfcp: Redesign of the debug tracing for HBA records.")
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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commit dac37e15b7d511e026a9313c8c46794c144103cd upstream.
When SCSI EH invokes zFCP's callbacks for eh_device_reset_handler() and
eh_target_reset_handler(), it expects us to relent the ownership over
the given scsi_cmnd and all other scsi_cmnds within the same scope - LUN
or target - when returning with SUCCESS from the callback ('release'
them). SCSI EH can then reuse those commands.
We did not follow this rule to release commands upon SUCCESS; and if
later a reply arrived for one of those supposed to be released commands,
we would still make use of the scsi_cmnd in our ingress tasklet. This
will at least result in undefined behavior or a kernel panic because of
a wrong kernel pointer dereference.
To fix this, we NULLify all pointers to scsi_cmnds (struct zfcp_fsf_req
*)->data in the matching scope if a TMF was successful. This is done
under the locks (struct zfcp_adapter *)->abort_lock and (struct
zfcp_reqlist *)->lock to prevent the requests from being removed from
the request-hashtable, and the ingress tasklet from making use of the
scsi_cmnd-pointer in zfcp_fsf_fcp_cmnd_handler().
For cases where a reply arrives during SCSI EH, but before we get a
chance to NULLify the pointer - but before we return from the callback
-, we assume that the code is protected from races via the CAS operation
in blk_complete_request() that is called in scsi_done().
The following stacktrace shows an example for a crash resulting from the
previous behavior:
Unable to handle kernel pointer dereference at virtual kernel address fffffee17a672000
Oops: 0038 [#1] SMP
CPU: 2 PID: 0 Comm: swapper/2 Not tainted
task: 00000003f7ff5be0 ti: 00000003f3d38000 task.ti: 00000003f3d38000
Krnl PSW : 0404d00180000000 00000000001156b0 (smp_vcpu_scheduled+0x18/0x40)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 EA:3
Krnl GPRS: 000000200000007e 0000000000000000 fffffee17a671fd8 0000000300000015
ffffffff80000000 00000000005dfde8 07000003f7f80e00 000000004fa4e800
000000036ce8d8f8 000000036ce8d9c0 00000003ece8fe00 ffffffff969c9e93
00000003fffffffd 000000036ce8da10 00000000003bf134 00000003f3b07918
Krnl Code: 00000000001156a2: a7190000 lghi %r1,0
00000000001156a6: a7380015 lhi %r3,21
#00000000001156aa: e32050000008 ag %r2,0(%r5)
>00000000001156b0: 482022b0 lh %r2,688(%r2)
00000000001156b4: ae123000 sigp %r1,%r2,0(%r3)
00000000001156b8: b2220020 ipm %r2
00000000001156bc: 8820001c srl %r2,28
00000000001156c0: c02700000001 xilf %r2,1
Call Trace:
([<0000000000000000>] 0x0)
[<000003ff807bdb8e>] zfcp_fsf_fcp_cmnd_handler+0x3de/0x490 [zfcp]
[<000003ff807be30a>] zfcp_fsf_req_complete+0x252/0x800 [zfcp]
[<000003ff807c0a48>] zfcp_fsf_reqid_check+0xe8/0x190 [zfcp]
[<000003ff807c194e>] zfcp_qdio_int_resp+0x66/0x188 [zfcp]
[<000003ff80440c64>] qdio_kick_handler+0xdc/0x310 [qdio]
[<000003ff804463d0>] __tiqdio_inbound_processing+0xf8/0xcd8 [qdio]
[<0000000000141fd4>] tasklet_action+0x9c/0x170
[<0000000000141550>] __do_softirq+0xe8/0x258
[<000000000010ce0a>] do_softirq+0xba/0xc0
[<000000000014187c>] irq_exit+0xc4/0xe8
[<000000000046b526>] do_IRQ+0x146/0x1d8
[<00000000005d6a3c>] io_return+0x0/0x8
[<00000000005d6422>] vtime_stop_cpu+0x4a/0xa0
([<0000000000000000>] 0x0)
[<0000000000103d8a>] arch_cpu_idle+0xa2/0xb0
[<0000000000197f94>] cpu_startup_entry+0x13c/0x1f8
[<0000000000114782>] smp_start_secondary+0xda/0xe8
[<00000000005d6efe>] restart_int_handler+0x56/0x6c
[<0000000000000000>] 0x0
Last Breaking-Event-Address:
[<00000000003bf12e>] arch_spin_lock_wait+0x56/0xb0
Suggested-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Fixes: ea127f9754 ("[PATCH] s390 (7/7): zfcp host adapter.") (tglx/history.git)
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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commit aceeffbb59bb91404a0bda32a542d7ebf878433a upstream.
This was lost with commit 2c55b750a884b86dea8b4cc5f15e1484cc47a25c
("[SCSI] zfcp: Redesign of the debug tracing for SAN records.")
but is necessary for problem determination, e.g. to see the
currently active zone set during automatic port scan.
For the large GPN_FT response (4 pages), save space by not dumping
any empty residual entries.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: 2c55b750a884 ("[SCSI] zfcp: Redesign of the debug tracing for SAN records.")
Reviewed-by: Alexey Ishchuk <aishchuk@linux.vnet.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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commit 7c964ffe586bc0c3d9febe9bf97a2e4b2866e5b7 upstream.
This information was lost with
commit a54ca0f62f953898b05549391ac2a8a4dad6482b
("[SCSI] zfcp: Redesign of the debug tracing for HBA records.")
but is required to debug e.g. invalid handle situations.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: a54ca0f62f95 ("[SCSI] zfcp: Redesign of the debug tracing for HBA records.")
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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commit 35f040df97fa0e94c7851c054ec71533c88b4b81 upstream.
While retaining the actual filtering according to trace level,
the following commits started to write such filtered records
with a hardcoded record level of 1 instead of the actual record level:
commit 250a1352b95e1db3216e5c5d4f4365bea5122f4a
("[SCSI] zfcp: Redesign of the debug tracing for SCSI records.")
commit a54ca0f62f953898b05549391ac2a8a4dad6482b
("[SCSI] zfcp: Redesign of the debug tracing for HBA records.")
Now we can distinguish written records again for offline level filtering.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: 250a1352b95e ("[SCSI] zfcp: Redesign of the debug tracing for SCSI records.")
Fixes: a54ca0f62f95 ("[SCSI] zfcp: Redesign of the debug tracing for HBA records.")
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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commit 4eeaa4f3f1d6c47b69f70e222297a4df4743363e upstream.
On a successful end of reopen port forced,
zfcp_erp_strategy_followup_success() re-uses the port erp_action
and the subsequent zfcp_erp_action_cleanup() now
sees ZFCP_ERP_SUCCEEDED with
erp_action->action==ZFCP_ERP_ACTION_REOPEN_PORT
instead of ZFCP_ERP_ACTION_REOPEN_PORT_FORCED
but must not perform zfcp_scsi_schedule_rport_register().
We can detect this because the fresh port reopen erp_action
is in its very first step ZFCP_ERP_STEP_UNINITIALIZED.
Otherwise this opens a time window with unblocked rport
(until the followup port reopen recovery would block it again).
If a scsi_cmnd timeout occurs during this time window
fc_timed_out() cannot work as desired and such command
would indeed time out and trigger scsi_eh. This prevents
a clean and timely path failover.
This should not happen if the path issue can be recovered
on FC transport layer such as path issues involving RSCNs.
Also, unnecessary and repeated DID_IMM_RETRY for pending and
undesired new requests occur because internally zfcp still
has its zfcp_port blocked.
As follow-on errors with scsi_eh, it can cause,
in the worst case, permanently lost paths due to one of:
sd <scsidev>: [<scsidisk>] Medium access timeout failure. Offlining disk!
sd <scsidev>: Device offlined - not ready after error recovery
For fix validation and to aid future debugging with other recoveries
we now also trace (un)blocking of rports.
Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: 5767620c383a ("[SCSI] zfcp: Do not unblock rport from REOPEN_PORT_FORCED")
Fixes: a2fa0aede07c ("[SCSI] zfcp: Block FC transport rports early on errors")
Fixes: 5f852be9e11d ("[SCSI] zfcp: Fix deadlock between zfcp ERP and SCSI")
Fixes: 338151e06608 ("[SCSI] zfcp: make use of fc_remote_port_delete when target port is unavailable")
Fixes: 3859f6a248cb ("[PATCH] zfcp: add rports to enable scsi_add_device to work again")
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
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