• Steffen Maier's avatar
    scsi: zfcp: fix reaction on bit error threshold notification · 2190168a
    Steffen Maier authored
    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.
    
    Fixes: 1da177e4 ("Linux-2.6.12-rc2")
    Cc: <stable@vger.kernel.org> #2.6.30+
    Link: https://lore.kernel.org/r/20191001104949.42810-1-maier@linux.ibm.comReviewed-by: default avatarJens Remus <jremus@linux.ibm.com>
    Reviewed-by: default avatarBenjamin Block <bblock@linux.ibm.com>
    Signed-off-by: default avatarSteffen Maier <maier@linux.ibm.com>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    2190168a
zfcp_fsf.c 68.8 KB