[LU-11422] Make LNet Selftest post Health backward compatible

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.12.0
• Severity: 3
• Assignee: Sonia Sharma (Inactive)
• Reporter: Sonia Sharma (Inactive)

Description

LNet Selftest post LNet Health landing loses backward compatibility, which means lnet-selftest cannot be run between cross-version peers (Lustre 2.12 and pre Lustre 2.12). We should fix that.

In LNet Health feature, new health related stats have been added which changes the struct lnet_counters that we previously had (patch https://review.whamcloud.com/32949 "LU-9120 lnet: add global health statistics"). Due to this, struct srpc_stat_reply is changed as it looks like this -

 struct srpc_stat_reply {
        __u32                   str_status;
        struct lst_sid          str_sid;
        struct sfw_counters     str_fw; 
        struct srpc_counters    str_rpc;
        struct lnet_counters    str_lnet;
 } WIRE_ATTR;

 struct lnet_counters {
        __u32   msgs_alloc;
        __u32   msgs_max;
+       __u32   rst_alloc;
        __u32   errors;
        __u32   send_count;
        __u32   recv_count;
        __u32   route_count;
        __u32   drop_count;
+       __u32   resend_count;
+       __u32   response_timeout_count;
+       __u32   local_interrupt_count;
+       __u32   local_dropped_count;
+       __u32   local_aborted_count;
+       __u32   local_no_route_count;
+       __u32   local_timeout_count;
+       __u32   local_error_count;
+       __u32   remote_dropped_count;
+       __u32   remote_error_count;
+       __u32   remote_timeout_count;
+       __u32   network_timeout_count;
        __u64   send_length;
        __u64   recv_length;
        __u64   route_length;
        __u64   drop_length; 
} WIRE_ATTR;

 

Amir's idea - 
"What we can do is make a copy of the structure which is similar to the older one. And in the post health selftest we can have a translation function which takes the new structure and copies the relevant fields to the old one. This way selftest remains backwards compatible"

Issue Links

• is related to: LU-9120 LNet Network Health Feature