4.4-stable review patch. If anyone has any objections, please let me know.
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From: Steffen Maier maier@linux.ibm.com
commit fe67888fc007a76b81e37da23ce5bd8fb95890b0 upstream.
An already deleted SCSI device can exist on the Scsi_Host and remain there because something still holds a reference. A new SCSI device with the same H:C:T:L and FCP device, target port WWPN, and FCP LUN can be created. When we try to unblock an rport, we still find the deleted SCSI device and return early because the zfcp_scsi_dev of that SCSI device is not ZFCP_STATUS_COMMON_UNBLOCKED. Hence we miss to unblock the rport, even if the new proper SCSI device would be in good state.
Therefore, skip deleted SCSI devices when iterating the sdevs of the shost. [cf. __scsi_device_lookup{_by_target}() or scsi_device_get()]
The following abbreviated trace sequence can indicate such problem:
Area : REC Tag : ersfs_3 LUN : 0x4045400300000000 WWPN : 0x50050763031bd327 LUN status : 0x40000000 not ZFCP_STATUS_COMMON_UNBLOCKED Ready count : n not incremented yet Running count : 0x00000000 ERP want : 0x01 ERP need : 0xc1 ZFCP_ERP_ACTION_NONE
Area : REC Tag : ersfs_3 LUN : 0x4045400300000000 WWPN : 0x50050763031bd327 LUN status : 0x41000000 Ready count : n+1 Running count : 0x00000000 ERP want : 0x01 ERP need : 0x01
...
Area : REC Level : 4 only with increased trace level Tag : ertru_l LUN : 0x4045400300000000 WWPN : 0x50050763031bd327 LUN status : 0x40000000 Request ID : 0x0000000000000000 ERP status : 0x01800000 ERP step : 0x1000 ERP action : 0x01 ERP count : 0x00
NOT followed by a trace record with tag "scpaddy" for WWPN 0x50050763031bd327.
Signed-off-by: Steffen Maier maier@linux.ibm.com Fixes: 6f2ce1c6af37 ("scsi: zfcp: fix rport unblock race with LUN recovery") Cc: stable@vger.kernel.org #2.6.32+ Reviewed-by: Jens Remus jremus@linux.ibm.com Reviewed-by: Benjamin Block bblock@linux.ibm.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/s390/scsi/zfcp_erp.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/s390/scsi/zfcp_erp.c +++ b/drivers/s390/scsi/zfcp_erp.c @@ -1306,6 +1306,9 @@ static void zfcp_erp_try_rport_unblock(s struct zfcp_scsi_dev *zsdev = sdev_to_zfcp(sdev); int lun_status;
+ if (sdev->sdev_state == SDEV_DEL || + sdev->sdev_state == SDEV_CANCEL) + continue; if (zsdev->port != port) continue; /* LUN under port of interest */