[LU-6525] USe of unchecked ERR_PTR value from lov_sub_get

• Type: Bug
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.15.0
• Labels: smatch
• Severity: 3
• Assignee: WC Triage
• Reporter: Oleg Drokin

Description

smatch highlighted the issue of return value from lov_sub_get() being used in lov_io_read_ahead and lov_io_fault_start.
lov_sub_get can return ERR_PTR as it's return value, so it should be fixed.

Example incorrect code:

        sub = lov_sub_get(env, lio, stripe);

        lov_stripe_offset(loo->lo_lsm, cl_offset(obj, start), stripe, &suboff);
        rc = cl_io_read_ahead(sub->sub_env, sub->sub_io,
                              cl_index(lovsub2cl(r0->lo_sub[stripe]), suboff),
                              ra);