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[PATCH 4.4 035/112] zfcp: close window with unblocked rport during rport gone

From Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups linux.kernel
Subject [PATCH 4.4 035/112] zfcp: close window with unblocked rport during rport gone
Date 2016-10-26 15:10 +0200
Message-ID <sww7V-49u-93@gated-at.bofh.it> (permalink)
References <swvER-3Eq-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Steffen Maier <maier@linux.vnet.ibm.com>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/s390/scsi/zfcp_dbf.h  |    7 ++++++-
 drivers/s390/scsi/zfcp_erp.c  |   12 +++++++++---
 drivers/s390/scsi/zfcp_scsi.c |    8 +++++++-
 3 files changed, 22 insertions(+), 5 deletions(-)

--- a/drivers/s390/scsi/zfcp_dbf.h
+++ b/drivers/s390/scsi/zfcp_dbf.h
@@ -2,7 +2,7 @@
  * zfcp device driver
  * debug feature declarations
  *
- * Copyright IBM Corp. 2008, 2010
+ * Copyright IBM Corp. 2008, 2015
  */
 
 #ifndef ZFCP_DBF_H
@@ -17,6 +17,11 @@
 
 #define ZFCP_DBF_INVALID_LUN	0xFFFFFFFFFFFFFFFFull
 
+enum zfcp_dbf_pseudo_erp_act_type {
+	ZFCP_PSEUDO_ERP_ACTION_RPORT_ADD = 0xff,
+	ZFCP_PSEUDO_ERP_ACTION_RPORT_DEL = 0xfe,
+};
+
 /**
  * struct zfcp_dbf_rec_trigger - trace record for triggered recovery action
  * @ready: number of ready recovery actions
--- a/drivers/s390/scsi/zfcp_erp.c
+++ b/drivers/s390/scsi/zfcp_erp.c
@@ -3,7 +3,7 @@
  *
  * Error Recovery Procedures (ERP).
  *
- * Copyright IBM Corp. 2002, 2010
+ * Copyright IBM Corp. 2002, 2015
  */
 
 #define KMSG_COMPONENT "zfcp"
@@ -1217,8 +1217,14 @@ static void zfcp_erp_action_cleanup(stru
 		break;
 
 	case ZFCP_ERP_ACTION_REOPEN_PORT:
-		if (result == ZFCP_ERP_SUCCEEDED)
-			zfcp_scsi_schedule_rport_register(port);
+		/* This switch case might also happen after a forced reopen
+		 * was successfully done and thus overwritten with a new
+		 * non-forced reopen at `ersfs_2'. In this case, we must not
+		 * do the clean-up of the non-forced version.
+		 */
+		if (act->step != ZFCP_ERP_STEP_UNINITIALIZED)
+			if (result == ZFCP_ERP_SUCCEEDED)
+				zfcp_scsi_schedule_rport_register(port);
 		/* fall through */
 	case ZFCP_ERP_ACTION_REOPEN_PORT_FORCED:
 		put_device(&port->dev);
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -3,7 +3,7 @@
  *
  * Interface to Linux SCSI midlayer.
  *
- * Copyright IBM Corp. 2002, 2013
+ * Copyright IBM Corp. 2002, 2015
  */
 
 #define KMSG_COMPONENT "zfcp"
@@ -556,6 +556,9 @@ static void zfcp_scsi_rport_register(str
 	ids.port_id = port->d_id;
 	ids.roles = FC_RPORT_ROLE_FCP_TARGET;
 
+	zfcp_dbf_rec_trig("scpaddy", port->adapter, port, NULL,
+			  ZFCP_PSEUDO_ERP_ACTION_RPORT_ADD,
+			  ZFCP_PSEUDO_ERP_ACTION_RPORT_ADD);
 	rport = fc_remote_port_add(port->adapter->scsi_host, 0, &ids);
 	if (!rport) {
 		dev_err(&port->adapter->ccw_device->dev,
@@ -577,6 +580,9 @@ static void zfcp_scsi_rport_block(struct
 	struct fc_rport *rport = port->rport;
 
 	if (rport) {
+		zfcp_dbf_rec_trig("scpdely", port->adapter, port, NULL,
+				  ZFCP_PSEUDO_ERP_ACTION_RPORT_DEL,
+				  ZFCP_PSEUDO_ERP_ACTION_RPORT_DEL);
 		fc_remote_port_delete(rport);
 		port->rport = NULL;
 	}

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[PATCH 4.4 000/112] 4.4.28-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 14:50 +0200
  [PATCH 4.4 061/112] NFSv4: Dont report revoked delegations as valid in nfs_have_delegation() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 084/112] irqchip/gicv3: Handle loop timeout proper Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 028/112] powerpc/powernv: Use CPU-endian hub diag-data type in pnv_eeh_get_and_dump_hub_diag() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 051/112] ALSA: hda - Fix a failure of micmute led when having multi adcs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 074/112] Clarify locking of cifs file and tcon structures and make more granular Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 027/112] powerpc/powernv: Pass CPU-endian PE number to opal_pci_eeh_freeze_clear() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 071/112] fs/super.c: fix race between freeze_super() and thaw_super() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 077/112] SMB3: GUIDs should be constructed as random but valid uuids Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 019/112] perf intel-pt: Fix snapshot overlap detection decoder errors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 024/112] dm mpath: check if paths request_queue is dying in activate_path() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 072/112] cifs: Limit the overall credit acquired Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 070/112] arc: dont leak bits of kernel stack into coredump Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 057/112] Input: i8042 - skip selftest on ASUS laptops Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 054/112] lib: move strtobool() to kstrtobool() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 037/112] zfcp: restore: Dont use 0 to indicate invalid LUN in rec trace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 058/112] Input: elantech - force needed quirks on Fujitsu H760 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 055/112] lib: update single-char callers of strtobool() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 060/112] sunrpc: fix write space race causing stalls Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 053/112] MIPS: ptrace: Fix regs_return_value for kernel context Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 056/112] lib: add "on"/"off" support to kstrtobool Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:00 +0200
  [PATCH 4.4 010/112] platform: dont return 0 from platform_get_irq[_byname]() on error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 047/112] [media] mb86a20s: fix the locking logic Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 022/112] dm: mark request_queue dead before destroying the DM device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 021/112] perf intel-pt: Fix MTC timestamp calculation for large MTC periods Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 043/112] scsi: zfcp: spin_lock_irqsave() is not nestable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 017/112] pstore/ram: Use memcpy_toio instead of memcpy Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 041/112] zfcp: fix payload trace length for SAN request&response Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 050/112] [media] cx231xx: fix GPIOs for Pixelview SBTVD hybrid Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 049/112] [media] cx231xx: dont return error on success Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 044/112] fbdev/efifb: Fix 16 color palette entry calculation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 048/112] [media] mb86a20s: fix demod settings Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 015/112] pstore/ramoops: fixup driver removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 032/112] ubi: Deal with interrupted erasures in WL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 046/112] ovl: copy_up_xattr(): use strnlen Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 036/112] zfcp: retain trace level for SCSI and HBA FSF response records Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 013/112] parisc: Fix kernel memory layout regarding position of __gp Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 011/112] cpufreq: intel_pstate: Fix unsafe HWP MSR access Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 038/112] zfcp: trace on request for open and close of WKA port Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 035/112] zfcp: close window with unblocked rport during rport gone Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 034/112] zfcp: fix ELS/GS request&response length for hardware data router Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 042/112] zfcp: trace full payload of all SAN records (req,resp,iels) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 040/112] zfcp: fix D_ID field with actual value on tracing SAN responses Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 045/112] ovl: Fix info leak in ovl_lookup_temp() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  [PATCH 4.4 033/112] zfcp: fix fc_host port_type with NPIV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-10-26 15:10 +0200
  Re: [PATCH 4.4 000/112] 4.4.28-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-10-26 20:50 +0200
  Re: [PATCH 4.4 000/112] 4.4.28-stable review Guenter Roeck <linux@roeck-us.net> - 2016-10-26 23:50 +0200

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