On Thu, Jun 22, 2017 at 04:59:12PM +0200, Martin Wilck wrote:
> Setting a device handler only works if retain_attached_hw_handler
> is 'no', or if the kernel didn't auto-assign a handler. If this
> is not the case, don't even attempt to set a different handler.
>
> This requires reading the sysfs "dh_state" path attribute.
>
> Signed-off-by: Martin Wilck <mwi...@suse.com>
ACK
-Ben
> ---
> libmultipath/configure.c | 8 +++++++-
> libmultipath/propsel.c | 35 +++++++++++++++++++++++++++++++++++
> 2 files changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/libmultipath/configure.c b/libmultipath/configure.c
> index 74b6f52a..03874f47 100644
> --- a/libmultipath/configure.c
> +++ b/libmultipath/configure.c
> @@ -275,15 +275,21 @@ int setup_map(struct multipath *mpp, char *params, int
> params_size)
>
> /*
> * properties selectors
> + *
> + * Ordering matters for some properties:
> + * - features after no_path_retry and retain_hwhandler
> + * - hwhandler after retain_hwhandler
> + * No guarantee that this list is complete, check code in
> + * propsel.c if in doubt.
> */
> conf = get_multipath_config();
> select_pgfailback(conf, mpp);
> select_pgpolicy(conf, mpp);
> select_selector(conf, mpp);
> - select_hwhandler(conf, mpp);
> select_no_path_retry(conf, mpp);
> select_retain_hwhandler(conf, mpp);
> select_features(conf, mpp);
> + select_hwhandler(conf, mpp);
> select_rr_weight(conf, mpp);
> select_minio(conf, mpp);
> select_mode(conf, mpp);
> diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
> index d609394e..a86207a0 100644
> --- a/libmultipath/propsel.c
> +++ b/libmultipath/propsel.c
> @@ -19,8 +19,10 @@
> #include "discovery.h"
> #include "dict.h"
> #include "util.h"
> +#include "sysfs.h"
> #include "prioritizers/alua_rtpg.h"
> #include <inttypes.h>
> +#include <libudev.h>
>
> pgpolicyfn *pgpolicies[] = {
> NULL,
> @@ -342,9 +344,42 @@ out:
> return 0;
> }
>
> +static int get_dh_state(struct path *pp, char *value, size_t value_len)
> +{
> + struct udev_device *ud;
> +
> + if (pp->udev == NULL)
> + return -1;
> +
> + ud = udev_device_get_parent_with_subsystem_devtype(
> + pp->udev, "scsi", "scsi_device");
> + if (ud == NULL)
> + return -1;
> +
> + return sysfs_attr_get_value(ud, "dh_state", value, value_len);
> +}
> +
> int select_hwhandler(struct config *conf, struct multipath *mp)
> {
> char *origin;
> + struct path *pp;
> + /* dh_state is no longer than "detached" */
> + char handler[12];
> + char *dh_state;
> + int i;
> +
> + dh_state = &handler[2];
> + if (mp->retain_hwhandler != RETAIN_HWHANDLER_OFF) {
> + vector_foreach_slot(mp->paths, pp, i) {
> + if (get_dh_state(pp, dh_state, sizeof(handler) - 2) > 0
> + && strcmp(dh_state, "detached")) {
> + memcpy(handler, "1 ", 2);
> + mp->hwhandler = handler;
> + origin = "(setting: retained by kernel driver)";
> + goto out;
> + }
> + }
> + }
>
> mp_set_hwe(hwhandler);
> mp_set_conf(hwhandler);
> --
> 2.13.1
--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel
