On Tue, Oct 30, 2018 at 10:06:44PM +0100, Martin Wilck wrote:
> A checker shouldn't set the path state to PATH_DOWN if it fails
> to obtain information about the path in the first place. Add logic
> to the checker to distinguish a failed path from an unsupported path.
> 
Reviewed-by: Benjamin Marzinski <bmarz...@redhat.com>
> Signed-off-by: Martin Wilck <mwi...@suse.com>
> ---
>  libmultipath/checkers/emc_clariion.c | 54 ++++++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
> 
> diff --git a/libmultipath/checkers/emc_clariion.c 
> b/libmultipath/checkers/emc_clariion.c
> index f8e55b93..6fc89113 100644
> --- a/libmultipath/checkers/emc_clariion.c
> +++ b/libmultipath/checkers/emc_clariion.c
> @@ -20,6 +20,11 @@
>  #define INQUIRY_CMD     0x12
>  #define INQUIRY_CMDLEN  6
>  #define HEAVY_CHECK_COUNT       10
> +#define SCSI_COMMAND_TERMINATED      0x22
> +#define SCSI_CHECK_CONDITION 0x2
> +#define RECOVERED_ERROR              0x01
> +#define ILLEGAL_REQUEST              0x05
> +#define SG_ERR_DRIVER_SENSE  0x08
>  
>  /*
>   * Mechanism to track CLARiiON inactive snapshot LUs.
> @@ -130,7 +135,9 @@ int libcheck_check (struct checker * c)
>               (struct emc_clariion_checker_path_context *)c->context;
>       char wwnstr[33];
>       int ret;
> +     int retry_emc = 5;
>  
> +retry:
>       memset(&io_hdr, 0, sizeof (struct sg_io_hdr));
>       memset(sense_buffer, 0, 128);
>       memset(sb, 0, SENSE_BUFF_LEN);
> @@ -145,13 +152,60 @@ int libcheck_check (struct checker * c)
>       io_hdr.timeout = c->timeout * 1000;
>       io_hdr.pack_id = 0;
>       if (ioctl(c->fd, SG_IO, &io_hdr) < 0) {
> +             if (errno == ENOTTY) {
> +                     c->msgid = CHECKER_MSGID_UNSUPPORTED;
> +                     return PATH_WILD;
> +             }
>               c->msgid = MSG_CLARIION_QUERY_FAILED;
>               return PATH_DOWN;
>       }
> +
>       if (io_hdr.info & SG_INFO_OK_MASK) {
> +             switch (io_hdr.host_status) {
> +             case DID_BUS_BUSY:
> +             case DID_ERROR:
> +             case DID_SOFT_ERROR:
> +             case DID_TRANSPORT_DISRUPTED:
> +                     /* Transport error, retry */
> +                     if (--retry_emc)
> +                             goto retry;
> +                     break;
> +             default:
> +                     break;
> +             }
> +     }
> +
> +     if (SCSI_CHECK_CONDITION == io_hdr.status ||
> +         SCSI_COMMAND_TERMINATED == io_hdr.status ||
> +         SG_ERR_DRIVER_SENSE == (0xf & io_hdr.driver_status)) {
> +             if (io_hdr.sbp && (io_hdr.sb_len_wr > 2)) {
> +                     unsigned char *sbp = io_hdr.sbp;
> +                     int sense_key;
> +
> +                     if (sbp[0] & 0x2)
> +                             sense_key = sbp[1] & 0xf;
> +                     else
> +                             sense_key = sbp[2] & 0xf;
> +
> +                     if (sense_key == ILLEGAL_REQUEST) {
> +                             c->msgid = CHECKER_MSGID_UNSUPPORTED;
> +                             return PATH_WILD;
> +                     } else if (sense_key != RECOVERED_ERROR) {
> +                             condlog(1, "emc_clariion_checker: INQUIRY 
> failed with sense key %02x",
> +                                     sense_key);
> +                             c->msgid = MSG_CLARIION_QUERY_ERROR;
> +                             return PATH_DOWN;
> +                     }
> +             }
> +     }
> +
> +     if (io_hdr.info & SG_INFO_OK_MASK) {
> +             condlog(1, "emc_clariion_checker: INQUIRY failed without sense, 
> status %02x",
> +                     io_hdr.status);
>               c->msgid = MSG_CLARIION_QUERY_ERROR;
>               return PATH_DOWN;
>       }
> +
>       if (/* Verify the code page - right page & revision */
>           sense_buffer[1] != 0xc0 || sense_buffer[9] != 0x00) {
>               c->msgid = MSG_CLARIION_UNIT_REPORT;
> -- 
> 2.19.1

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