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For problem determination we always want to see when we were invoked on the
terminate_rport_io callback whether we perform something or not.
Temporal event sequence of interest with a long fast_io_fail_tmo of 27 sec:
loose remote port
t workqueue
[s] zfcp_q_<dev> IRQ zfcperp<dev>
=== ================== =================== ============================
0 recv RSCN
q p.test_link_work
block rport
start fast_io_fail_tmo
send ADISC ELS
4 recv ADISC fail
block zfcp_port
port forced reopen
send open port
12 recv open port fail
q p.gid_pn_work
zfcp_erp_wakeup
(zfcp_erp_wait would return)
GID_PN fail
Before this point, we got a SCSI trace with tag "sctrpi1" on fast_io_fail,
e.g. with the typical 5 sec setting.
port.status |= ERP_FAILED
If fast_io_fail_tmo triggers after this point, we missed a SCSI trace.
workqueue
fc_dl_<host>
==================
27 fc_timeout_fail_rport_io
fc_terminate_rport_io
zfcp_scsi_terminate_rport_io
zfcp_erp_port_forced_reopen
_zfcp_erp_port_forced_reopen
if (port.status & ERP_FAILED)
return;
Therefore, write a trace before above early return.
Example trace record formatted with zfcpdbf from s390-tools:
Timestamp : ...
Area : REC
Subarea : 00
Level : 1
Exception : -
CPU ID : ..
Caller : 0x...
Record ID : 1 ZFCP_DBF_REC_TRIG
Tag : sctrpi1 SCSI terminate rport I/O
LUN : 0xffffffffffffffff none (invalid)
WWPN : 0x<wwpn>
D_ID : 0x<n_port_id>
Adapter status : 0x...
Port status : 0x...
LUN status : 0x00000000 none (invalid)
Ready count : 0x...
Running count : 0x...
ERP want : 0x03 ZFCP_ERP_ACTION_REOPEN_PORT_FORCED
ERP need : 0xe0 ZFCP_ERP_ACTION_FAILED
Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Cc: <stable@vger.kernel.org> #2.6.38+
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.