Re: [PATCH 14/21] libmultipath: hp_sw checker: leave unsupported paths alone

["Benjamin Marzinski" <bmarzins@redhat.com>]

On Fri, Oct 12, 2018 at 12:27:00AM +0200, 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 <bmarzins@redhat.com>

> Signed-off-by: Martin Wilck <mwilck@suse.com>
> ---
>  libmultipath/checkers/hp_sw.c | 29 +++++++++++++++++++++--------
>  1 file changed, 21 insertions(+), 8 deletions(-)
> 
> diff --git a/libmultipath/checkers/hp_sw.c b/libmultipath/checkers/hp_sw.c
> index d7f1018c..1a820223 100644
> --- a/libmultipath/checkers/hp_sw.c
> +++ b/libmultipath/checkers/hp_sw.c
> @@ -24,6 +24,7 @@
>  #define SCSI_COMMAND_TERMINATED	0x22
>  #define SG_ERR_DRIVER_SENSE	0x08
>  #define RECOVERED_ERROR		0x01
> +#define ILLEGAL_REQUEST		0x05
>  #define MX_ALLOC_LEN		255
>  #define HEAVY_CHECK_COUNT       10
>  
> @@ -68,14 +69,19 @@ do_inq(int sg_fd, int cmddt, int evpd, unsigned int pg_op,
>  	io_hdr.sbp = sense_b;
>  	io_hdr.timeout = timeout * 1000;
>  
> -	if (ioctl(sg_fd, SG_IO, &io_hdr) < 0)
> -		return 1;
> +	if (ioctl(sg_fd, SG_IO, &io_hdr) < 0) {
> +		if (errno == ENOTTY)
> +			return PATH_WILD;
> +		else
> +			return PATH_DOWN;
> +	}
>  
>  	/* treat SG_ERR here to get rid of sg_err.[ch] */
>  	io_hdr.status &= 0x7e;
>  	if ((0 == io_hdr.status) && (0 == io_hdr.host_status) &&
>  	    (0 == io_hdr.driver_status))
> -		return 0;
> +		return PATH_UP;
> +
>  	if ((SCSI_CHECK_CONDITION == io_hdr.status) ||
>  	    (SCSI_COMMAND_TERMINATED == io_hdr.status) ||
>  	    (SG_ERR_DRIVER_SENSE == (0xf & io_hdr.driver_status))) {
> @@ -86,11 +92,13 @@ do_inq(int sg_fd, int cmddt, int evpd, unsigned int pg_op,
>  				sense_key = sense_buffer[1] & 0xf;
>  			else
>  				sense_key = sense_buffer[2] & 0xf;
> -			if(RECOVERED_ERROR == sense_key)
> -				return 0;
> +			if (RECOVERED_ERROR == sense_key)
> +				return PATH_UP;
> +			else if (ILLEGAL_REQUEST == sense_key)
> +				return PATH_WILD;
>  		}
>  	}
> -	return 1;
> +	return PATH_DOWN;
>  }
>  
>  static int
> @@ -122,10 +130,15 @@ do_tur (int fd, unsigned int timeout)
>  int libcheck_check(struct checker * c)
>  {
>  	char buff[MX_ALLOC_LEN];
> +	int ret = do_inq(c->fd, 0, 1, 0x80, buff, MX_ALLOC_LEN, 0, c->timeout);
>  
> -	if (0 != do_inq(c->fd, 0, 1, 0x80, buff, MX_ALLOC_LEN, 0, c->timeout)) {
> +	if (ret == PATH_WILD) {
> +		c->msgid = CHECKER_MSGID_UNSUPPORTED;
> +		return ret;
> +	}
> +	if (ret != PATH_UP) {
>  		c->msgid = CHECKER_MSGID_DOWN;
> -		return PATH_DOWN;
> +		return ret;
>  	};
>  
>  	if (do_tur(c->fd, c->timeout)) {
> -- 
> 2.19.0