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  1. Lustre
  2. LU-8698

DNE3: check unknown hash type properly in lmv

    Details

    • Type: Bug
    • Status: Open
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: None
    • Labels:
    • Severity:
      3
    • Rank (Obsolete):
      9223372036854775807

      Description

      The patch 893ab7479263: "staging: lustre: lmv: try all stripes for
      unknown hash functions" from Aug 16, 2016, leads to the following
      static checker warning:

      	drivers/staging/lustre/lustre/lmv/lmv_intent.c:397 lmv_intent_lookup()
      	error: 'tgt' dereferencing possible ERR_PTR()
      
      drivers/staging/lustre/lustre/lmv/lmv_intent.c
        361                               struct ptlrpc_request **reqp,
         362                               ldlm_blocking_callback cb_blocking,
         363                               __u64 extra_lock_flags)
         364  {
         365          struct lmv_stripe_md *lsm = op_data->op_mea1;
         366          struct obd_device      *obd = exp->exp_obd;
         367          struct lmv_obd   *lmv = &obd->u.lmv;
         368          struct lmv_tgt_desc    *tgt = NULL;
         369          struct mdt_body *body;
         370          int                  rc = 0;
         371  
         372          /*
         373           * If it returns ERR_PTR(-EBADFD) then it is an unknown hash type
         374           * it will try all stripes to locate the object
         375           */
      

      I have read this comment so I assume that this warning is a false
      positive.

         376          tgt = lmv_locate_mds(lmv, op_data, &op_data->op_fid1);
         377          if (IS_ERR(tgt) && (PTR_ERR(tgt) != -EBADFD))
         378                  return PTR_ERR(tgt);
         379  
         380          /*
         381           * Both migrating dir and unknown hash dir need to try
         382           * all of sub-stripes
         383           */
         384          if (lsm && !lmv_is_known_hash_type(lsm->lsm_md_hash_type)) {
      

      But really, it's pretty ugly to assume that -EBADFD implies that lsm is
      non-NULL and lmv_is_known_hash_type() will return false.

      Yes, it might be a bit improper to use -EBADFD here to indicate this
      special scenario, or it can be

      if (IS_ERR(tgt)) {
            if (PTR_ERR(tgt) != -EBADFD)  /* hmm, this might not needed, needs
      further check */
                 return PTR_ERR(tgt);
      
            if (lsm && !lmv_is_known_hash_type(lsm->lsm_md_hash_type)) {
                 ŠŠ..
            } else {
                 return PTR_ERR(tgt);
            }
      }
      
         385                  struct lmv_oinfo *oinfo = &lsm->lsm_md_oinfo[0];
         386  
         387                  op_data->op_fid1 = oinfo->lmo_fid;
         388                  op_data->op_mds = oinfo->lmo_mds;
         389                  tgt = lmv_get_target(lmv, oinfo->lmo_mds, NULL);
         390                  if (IS_ERR(tgt))
         391                          return PTR_ERR(tgt);
         392          }
         393  
         394          if (!fid_is_sane(&op_data->op_fid2))
         395                  fid_zero(&op_data->op_fid2);
         396  
         397          CDEBUG(D_INODE, "LOOKUP_INTENT with fid1=" DFID ", fid2=" DFID ", name='%s' -> mds #%u lsm=%p lsm_magic=%x\n",
         398                 PFID(&op_data->op_fid1), PFID(&op_data->op_fid2),
         399                 op_data->op_name ? op_data->op_name : "<NULL>",
         400                 tgt->ltd_idx, lsm, !lsm ? -1 : lsm->lsm_md_magic);
         401  
         402          op_data->op_bias &= ~MDS_CROSS_REF;
      

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              • Assignee:
                wc-triage WC Triage
                Reporter:
                di.wang Di Wang
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                Dates

                • Created:
                  Updated: