NFSD: always drop directory lock in nfsd_unlink()

Some error paths in nfsd_unlink() allow it to exit without unlocking the
directory.  This is not a problem in practice as the directory will be
locked with an fh_put(), but it is untidy and potentially confusing.

This allows us to remove all the fh_unlock() calls that are immediately
after nfsd_unlink() calls.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs3proc.c

@@ -490,7 +490,6 @@ nfsd3_proc_remove(struct svc_rqst *rqstp)
 	fh_copy(&resp->fh, &argp->fh);
 	resp->status = nfsd_unlink(rqstp, &resp->fh, -S_IFDIR,
 				   argp->name, argp->len);
-	fh_unlock(&resp->fh);
 	return rpc_success;
 }
 
@@ -511,7 +510,6 @@ nfsd3_proc_rmdir(struct svc_rqst *rqstp)
 	fh_copy(&resp->fh, &argp->fh);
 	resp->status = nfsd_unlink(rqstp, &resp->fh, S_IFDIR,
 				   argp->name, argp->len);
-	fh_unlock(&resp->fh);
 	return rpc_success;
 }
 

fs/nfsd/nfs4proc.c

@@ -1002,10 +1002,8 @@ nfsd4_remove(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		return nfserr_grace;
 	status = nfsd_unlink(rqstp, &cstate->current_fh, 0,
 			     remove->rm_name, remove->rm_namelen);
-	if (!status) {
-		fh_unlock(&cstate->current_fh);
+	if (!status)
 		set_change_info(&remove->rm_cinfo, &cstate->current_fh);
-	}
 	return status;
 }
 

fs/nfsd/vfs.c

@@ -1753,12 +1753,12 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	rdentry = lookup_one_len(fname, dentry, flen);
 	host_err = PTR_ERR(rdentry);
 	if (IS_ERR(rdentry))
-		goto out_drop_write;
+		goto out_unlock;
 
 	if (d_really_is_negative(rdentry)) {
 		dput(rdentry);
 		host_err = -ENOENT;
-		goto out_drop_write;
+		goto out_unlock;
 	}
 	rinode = d_inode(rdentry);
 	ihold(rinode);
@@ -1796,6 +1796,9 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	}
 out:
 	return err;
+out_unlock:
+	fh_unlock(fhp);
+	goto out_drop_write;
 }
 
 /*