On excessive bit errors for the FCP channel ingress fibre path, the channel
notifies us. Previously, we only emitted a kernel message and a trace record.
Since performance can become suboptimal with I/O timeouts due to
bit errors, we now stop using an FCP device by default on channel
notification so multipath on top can timely failover to other paths.
A new module parameter zfcp.ber_stop can be used to get zfcp old behavior.
User explanation of new kernel message:
* Description:
* The FCP channel reported that its bit error threshold has been exceeded.
* These errors might result from a problem with the physical components
* of the local fibre link into the FCP channel.
* The problem might be damage or malfunction of the cable or
* cable connection between the FCP channel and
* the adjacent fabric switch port or the point-to-point peer.
* Find details about the errors in the HBA trace for the FCP device.
* The zfcp device driver closed down the FCP device
* to limit the performance impact from possible I/O command timeouts.
* User action:
* Check for problems on the local fibre link, ensure that fibre optics are
* clean and functional, and all cables are properly plugged.
* After the repair action, you can manually recover the FCP device by
* writing "0" into its "failed" sysfs attribute.
* If recovery through sysfs is not possible, set the CHPID of the device
* offline and back online on the service element.
Signed-off-by: Steffen Maier <maier@xxxxxxxxxxxxx>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: <stable@xxxxxxxxxxxxxxx> #2.6.30+
Reviewed-by: Jens Remus <jremus@xxxxxxxxxxxxx>
Reviewed-by: Benjamin Block <bblock@xxxxxxxxxxxxx>
---
Martin, James,
an important zfcp fix for v5.4-rc.
It applies to Martin's 5.4/scsi-fixes or to James' fixes branch.
Changes since v1:
* Martin's review comments: describe code change and new module parameter
drivers/s390/scsi/zfcp_fsf.c | 16 +++++++++++++---
2 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index e31c6b47af97..1e279220f073 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -29,6 +29,11 @@
struct kmem_cache *zfcp_fsf_qtcb_cache;
+static bool ber_stop = true;
+module_param(ber_stop, bool, 0600);
+MODULE_PARM_DESC(ber_stop,
+ "Shuts down FCP devices for FCP channels that report a bit-error count in excess of its threshold (default on)");
+
static void zfcp_fsf_request_timeout_handler(struct timer_list *t)
{
struct zfcp_fsf_req *fsf_req = from_timer(fsf_req, t, timer);
@@ -238,10 +243,15 @@ static void zfcp_fsf_status_read_handler(struct zfcp_fsf_req *req)
case FSF_STATUS_READ_SENSE_DATA_AVAIL:
break;
case FSF_STATUS_READ_BIT_ERROR_THRESHOLD:
- dev_warn(&adapter->ccw_device->dev,
- "The error threshold for checksum statistics "
- "has been exceeded\n");
zfcp_dbf_hba_bit_err("fssrh_3", req);
+ if (ber_stop) {
+ dev_warn(&adapter->ccw_device->dev,
+ "All paths over this FCP device are disused because of excessive bit errors\n");
+ zfcp_erp_adapter_shutdown(adapter, 0, "fssrh_b");
+ } else {
+ dev_warn(&adapter->ccw_device->dev,
+ "The error threshold for checksum statistics has been exceeded\n");
+ }
break;
case FSF_STATUS_READ_LINK_DOWN:
zfcp_fsf_status_read_link_down(req);
--
2.17.1
