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Date:   Wed, 4 Dec 2019 11:00:39 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     olga.kornievskaia@gmail.com
Cc:     linux-nfs@vger.kernel.org
Subject: [bug report] NFSD: allow inter server COPY to have a STALE source
 server fh
Message-ID: <20191204080039.ixjqetefkzzlldyt@kili.mountain>
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Hello Olga Kornievskaia,

This is a semi-automatic email about new static checker warnings.

The patch 4e48f1cccab3: "NFSD: allow inter server COPY to have a 
STALE source server fh" from Oct 7, 2019, leads to the following 
Smatch complaint:

    fs/nfsd/nfs4proc.c:2371 nfsd4_proc_compound()
     error: we previously assumed 'current_fh->fh_export' could be null (see line 2325)

fs/nfsd/nfs4proc.c
  2324				}
  2325			} else if (current_fh->fh_export &&
                                   ^^^^^^^^^^^^^^^^^^^^^
The patch adds a check for NULL

  2326				   current_fh->fh_export->ex_fslocs.migrated &&
  2327				  !(op->opdesc->op_flags & ALLOWED_ON_ABSENT_FS)) {
  2328				op->status = nfserr_moved;
  2329				goto encode_op;
  2330			}
  2331	
  2332			fh_clear_wcc(current_fh);
  2333	
  2334			/* If op is non-idempotent */
  2335			if (op->opdesc->op_flags & OP_MODIFIES_SOMETHING) {
  2336				/*
  2337				 * Don't execute this op if we couldn't encode a
  2338				 * succesful reply:
  2339				 */
  2340				u32 plen = op->opdesc->op_rsize_bop(rqstp, op);
  2341				/*
  2342				 * Plus if there's another operation, make sure
  2343				 * we'll have space to at least encode an error:
  2344				 */
  2345				if (resp->opcnt < args->opcnt)
  2346					plen += COMPOUND_ERR_SLACK_SPACE;
  2347				op->status = nfsd4_check_resp_size(resp, plen);
  2348			}
  2349	
  2350			if (op->status)
  2351				goto encode_op;
  2352	
  2353			if (op->opdesc->op_get_currentstateid)
  2354				op->opdesc->op_get_currentstateid(cstate, &op->u);
  2355			op->status = op->opdesc->op_func(rqstp, cstate, &op->u);
  2356	
  2357			/* Only from SEQUENCE */
  2358			if (cstate->status == nfserr_replay_cache) {
  2359				dprintk("%s NFS4.1 replay from cache\n", __func__);
  2360				status = op->status;
  2361				goto out;
  2362			}
  2363			if (!op->status) {
  2364				if (op->opdesc->op_set_currentstateid)
  2365					op->opdesc->op_set_currentstateid(cstate, &op->u);
  2366	
  2367				if (op->opdesc->op_flags & OP_CLEAR_STATEID)
  2368					clear_current_stateid(cstate);
  2369	
  2370				if (need_wrongsec_check(rqstp))
  2371					op->status = check_nfsd_access(current_fh->fh_export, rqstp);
                                                                       ^^^^^^^^^^^^^^^^^^^^^
Is it required here as well?

  2372			}
  2373	encode_op:

regards,
dan carpenter