On Wed, 2020-11-04 at 00:54 -0600, Benjamin Marzinski wrote:
> Only rdac arrays support 0xC9 vpd page inquiries. All other arrays
> will
> return a failure. Only do the rdac inquiry when detecting array
> capabilities if the array's path checker is explicitly set to rdac,
> or
> the path checker is not set, and the array reports that it supports
> vpd
> page 0xC9 in the Supported VPD Pages (0x00) vpd page.
>
> Multipath was doing the check if either the path checker was set to
> rdac, or no path checker was set. This means that for almost all
> non-rdac arrays, multipath was issuing a bad inquiry. This was
> annoying
> users.
>
> Cc: Steve Schremmer <sschremm@xxxxxxxxxx>
> Cc: NetApp RDAC team <ng-eseries-upstream-maintainers@xxxxxxxxxx>
> Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> ---
> libmultipath/discovery.c | 25 +++++++++++++++++++++++++
> libmultipath/discovery.h | 1 +
> libmultipath/propsel.c | 10 ++++++----
> 3 files changed, 32 insertions(+), 4 deletions(-)
>
> diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
> index 95ddbbbd..5669690d 100644
> --- a/libmultipath/discovery.c
> +++ b/libmultipath/discovery.c
> @@ -1346,6 +1346,31 @@ fetch_vpd_page(int fd, int pg, unsigned char
> *buff)
> return buff_len;
> }
>
> +/* heavily based on sg_inq.c from sg3_utils */
> +bool
> +is_vpd_page_supported(int fd, int pg)
> +{
> + int i, len, buff_len;
> + unsigned char buff[4096];
> +
> + buff_len = fetch_vpd_page(fd, 0x00, buff);
> + if (buff_len < 0)
> + return false;
> + if (buff_len < 4) {
> + condlog(3, "VPD page 00h too short");
> + return false;
> + }
> +
> + len = buff[3] + 4;
SPC-4 says that the page length is a 16-bit value.
You may also want to check buff[1] == 0.
> + if (len > buff_len)
> + condlog(3, "vpd page 00h trucated, expected %d, have
> %d",
> + len, buff_len);
> + for (i = 4; i < len; ++i)
> + if (buff[i] == pg)
> + return true;
> + return false;
> +}
> +
> int
> get_vpd_sgio (int fd, int pg, int vend_id, char * str, int maxlen)
> {
> diff --git a/libmultipath/discovery.h b/libmultipath/discovery.h
> index 6444887d..d3193daf 100644
> --- a/libmultipath/discovery.h
> +++ b/libmultipath/discovery.h
> @@ -56,6 +56,7 @@ int sysfs_get_asymmetric_access_state(struct path
> *pp,
> char *buff, int buflen);
> int get_uid(struct path * pp, int path_state, struct udev_device
> *udev,
> int allow_fallback);
> +bool is_vpd_page_supported(int fd, int pg);
>
> /*
> * discovery bitmask
> diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
> index fa4ac5d9..f771a830 100644
> --- a/libmultipath/propsel.c
> +++ b/libmultipath/propsel.c
> @@ -496,13 +496,15 @@ check_rdac(struct path * pp)
> {
> int len;
> char buff[44];
> - const char *checker_name;
> + const char *checker_name = NULL;
>
> if (pp->bus != SYSFS_BUS_SCSI)
> return 0;
> - /* Avoid ioctl if this is likely not an RDAC array */
> - if (__do_set_from_hwe(checker_name, pp, checker_name) &&
> - strcmp(checker_name, RDAC))
> + /* Avoid checking 0xc9 if this is likely not an RDAC array */
> + if (!__do_set_from_hwe(checker_name, pp, checker_name) &&
> + !is_vpd_page_supported(pp->fd, 0xC9))
> + return 0;
> + if (checker_name && strcmp(checker_name, RDAC))
Do we still need the name check after testing whether 0xc9 is
supported? Well I guess it doesn't harm.
Regards
Martin
> return 0;
> len = get_vpd_sgio(pp->fd, 0xC9, 0, buff, 44);
> if (len <= 0)
--
Dr. Martin Wilck <mwilck@xxxxxxxx>, Tel. +49 (0)911 74053 2107
SUSE Software Solutions Germany GmbH
HRB 36809, AG Nürnberg GF: Felix
Imendörffer
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