+ if (nfsd_vers(4, NFSD_AVAIL))
+ for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION;
+ minor++) {
+ len = snprintf(buf, remaining, " %c4.%u",
+ (nfsd_vers(4, NFSD_TEST) &&
+ nfsd_minorversion(minor, NFSD_TEST)) ?
+ '+' : '-',
+ minor);
+
+ if (len > remaining)
+ break;
+ remaining -= len;
+ buf += len;
+ tlen += len;
+ }
+
+ len = snprintf(buf, remaining, "\n");
+ if (len > remaining)
+ return -EINVAL;
+ return tlen + len;
+}
+
+/**
+ * write_versions - Set or report the available NFS protocol versions
+ *
+ * Input:
+ * buf: ignored
+ * size: zero
+ * Output:
+ * On success: passed-in buffer filled with '\n'-terminated C
+ * string containing positive or negative integer
+ * values representing the current status of each
+ * protocol version;
+ * return code is the size in bytes of the string
+ * On error: return code is zero or a negative errno value
+ *
+ * OR
+ *
+ * Input:
+ * buf: C string containing whitespace-
+ * separated positive or negative
+ * integer values representing NFS
+ * protocol versions to enable ("+n")
+ * or disable ("-n")
+ * size: non-zero length of C string in @buf
+ * Output:
+ * On success: status of zero or more protocol versions has
+ * been updated; passed-in buffer filled with
+ * '\n'-terminated C string containing positive
+ * or negative integer values representing the
+ * current status of each protocol version;
+ * return code is the size in bytes of the string
+ * On error: return code is zero or a negative errno value
+ */
+static ssize_t write_versions(struct file *file, char *buf, size_t size)
+{
+ ssize_t rv;
+
+ mutex_lock(&nfsd_mutex);
+ rv = __write_versions(file, buf, size);
+ mutex_unlock(&nfsd_mutex);
+ return rv;
+}
+
+/*
+ * Zero-length write. Return a list of NFSD's current listener
+ * transports.
+ */
+static ssize_t __write_ports_names(char *buf)
+{
+ if (nfsd_serv == NULL)
+ return 0;
+ return svc_xprt_names(nfsd_serv, buf, SIMPLE_TRANSACTION_LIMIT);
+}
+
+/*
+ * A single 'fd' number was written, in which case it must be for
+ * a socket of a supported family/protocol, and we use it as an
+ * nfsd listener.
+ */
+static ssize_t __write_ports_addfd(char *buf)
+{
+ char *mesg = buf;
+ int fd, err;
+
+ err = get_int(&mesg, &fd);
+ if (err != 0 || fd < 0)
+ return -EINVAL;
+
+ err = nfsd_create_serv();
+ if (err != 0)
+ return err;
+
+ err = lockd_up();
+ if (err != 0)
+ goto out;
+
+ err = svc_addsock(nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT);
+ if (err < 0)
+ lockd_down();
+
+out:
+ /* Decrease the count, but don't shut down the service */
+ nfsd_serv->sv_nrthreads--;
+ return err;
+}
+
+/*
+ * A '-' followed by the 'name' of a socket means we close the socket.
+ */
+static ssize_t __write_ports_delfd(char *buf)
+{
+ char *toclose;
+ int len = 0;
+
+ toclose = kstrdup(buf + 1, GFP_KERNEL);
+ if (toclose == NULL)
+ return -ENOMEM;
+
+ if (nfsd_serv != NULL)
+ len = svc_sock_names(nfsd_serv, buf,
+ SIMPLE_TRANSACTION_LIMIT, toclose);
+ if (len >= 0)
+ lockd_down();
+
+ kfree(toclose);