Backport NFS4 only support

See: xapi-project#617

Signed-off-by: Benjamin Reis <benjamin.reis@vates.tech>

drivers/NFSSR.py

@@ -115,11 +115,12 @@ def validate_remotepath(self, scan):
     def check_server(self):
         try:
             if self.dconf.has_key(PROBEVERSION):
-                sv = nfs.get_supported_nfs_versions(self.remoteserver)
+                sv = nfs.get_supported_nfs_versions(self.remoteserver, self.transport)
                 if len(sv):
                     self.nfsversion = sv[0]
             else:
-                nfs.check_server_tcp(self.remoteserver, self.nfsversion)
+                if not nfs.check_server_tcp(self.remoteserver, self.transport, self.nfsversion):
+                    raise nfs.NfsException("Unsupported NFS version: %s" % self.nfsversion)
         except nfs.NfsException, exc:
             raise xs_errors.XenError('NFSVersion',
                                      opterr=exc.errstr)
@@ -174,7 +175,7 @@ def probe(self):
 
         self.mount(temppath, self.remotepath)
         try:
-            return nfs.scan_srlist(temppath, self.dconf)
+            return nfs.scan_srlist(temppath, self.transport, self.dconf)
         finally:
             try:
                 nfs.unmount(temppath, True)
@@ -268,7 +269,7 @@ def vdi(self, uuid, loadLocked = False):
 
     def scan_exports(self, target):
         util.SMlog("scanning2 (target=%s)" % target)
-        dom = nfs.scan_exports(target)
+        dom = nfs.scan_exports(target, self.transport)
         print >>sys.stderr,dom.toprettyxml()
 
 class NFSFileVDI(FileSR.FileVDI):

drivers/nfs.py

@@ -44,6 +44,7 @@
 
 RPCINFO_BIN = "/usr/sbin/rpcinfo"
 SHOWMOUNT_BIN = "/usr/sbin/showmount"
+NFS_STAT = "/usr/sbin/nfsstat"
 
 DEFAULT_NFSVERSION = '3'
 
@@ -53,32 +54,40 @@
 NFS_SERVICE_WAIT = 30
 NFS_SERVICE_RETRY = 6
 
+NFS4_PSEUDOFS = "/"
+NFS4_TMP_MOUNTPOINT = "/tmp/mnt"
+
 class NfsException(Exception):
 
     def __init__(self, errstr):
         self.errstr = errstr
 
 
-def check_server_tcp(server, nfsversion=DEFAULT_NFSVERSION):
+def check_server_tcp(server, transport, nfsversion=DEFAULT_NFSVERSION):
     """Make sure that NFS over TCP/IP V3 is supported on the server.
 
     Returns True if everything is OK
     False otherwise.
     """
     try:
-        sv = get_supported_nfs_versions(server)
-        return (True if nfsversion in sv else False)
+        sv = get_supported_nfs_versions(server, transport)
+        return (nfsversion[0] in sv)
     except util.CommandException, inst:
         raise NfsException("rpcinfo failed or timed out: return code %d" %
                            inst.code)
 
-def check_server_service(server):
+def check_server_service(server, transport):
     """Ensure NFS service is up and available on the remote server.
 
     Returns False if fails to detect service after 
     NFS_SERVICE_RETRY * NFS_SERVICE_WAIT
     """
 
+    sv = get_supported_nfs_versions(server, transport)
+    # Services are not present in NFS4 only, this doesn't mean there's no NFS
+    if sv == ['4']:
+        return True
+
     retries = 0
     errlist = [errno.EPERM, errno.EPIPE, errno.EIO]
 
@@ -131,14 +140,6 @@ def soft_mount(mountpoint, remoteserver, remotepath, transport, useroptions='',
                            inst.code)
 
 
-    # Wait for NFS service to be available
-    try: 
-        if not check_server_service(remoteserver):
-            raise util.CommandException(code=errno.EOPNOTSUPP,
-                    reason="No NFS service on host")
-    except util.CommandException, inst: 
-        raise NfsException("Failed to detect NFS service on server %s" 
-                           % remoteserver)
 
     mountcommand = 'mount.nfs'
     if nfsversion == '4':
@@ -184,13 +185,11 @@ def unmount(mountpoint, rmmountpoint):
             raise NfsException("rmdir failed with error '%s'" % inst.strerror)
 
 
-def scan_exports(target):
-    """Scan target and return an XML DOM with target, path and accesslist."""
-    util.SMlog("scanning")
+def _scan_exports_nfs3(target, dom, element):
+    """ Scan target and return an XML DOM with target, path and accesslist.
+        Using NFS3 services.
+    """
     cmd = [SHOWMOUNT_BIN, "--no-headers", "-e", target]
-    dom = xml.dom.minidom.Document()
-    element = dom.createElement("nfs-exports")
-    dom.appendChild(element)
     for val in util.pread2(cmd).split('\n'):
         if not len(val):
             continue
@@ -219,8 +218,56 @@ def scan_exports(target):
 
     return dom
 
+def _scan_exports_nfs4_only(target, transport, dom, element):
+    """ Scan target and return an XML DOM with target, path and accesslist.
+        Using NFS4 only pseudo FS.
+    """
+
+    mountpoint = "%s/%s" % (NFS4_TMP_MOUNTPOINT, target)
+    soft_mount(mountpoint, target, NFS4_PSEUDOFS, transport, nfsversion="4")
+    paths = os.listdir(mountpoint)
+    unmount(mountpoint, NFS4_PSEUDOFS)
+    for path in paths:
+        entry = dom.createElement("Export")
+        element.appendChild(entry)
+
+        subentry = dom.createElement("Target")
+        entry.appendChild(subentry)
+        textnode = dom.createTextNode(target)
+        subentry.appendChild(textnode)
+        subentry = dom.createElement("Path")
+        entry.appendChild(subentry)
+        textnode = dom.createTextNode(path)
+        subentry.appendChild(textnode)
+
+        subentry = dom.createElement("Accesslist")
+        entry.appendChild(subentry)
+        # Assume everyone as we do not have any info about it
+        textnode = dom.createTextNode("*")
+        subentry.appendChild(textnode)
+    return dom
+
+def scan_exports(target, transport):
+    """Scan target and return an XML DOM with target, path and accesslist."""
+    util.SMlog("scanning")
+    dom = xml.dom.minidom.Document()
+    element = dom.createElement("nfs-exports")
+    dom.appendChild(element)
+    try:
+        return _scan_exports_nfs3(target, dom, element)
+    except Exception:
+        util.SMlog("Unable to scan exports with %s, trying NFSv4" % SHOWMOUNT_BIN)
+
+    # NFSv4 only
+    try:
+        return _scan_exports_nfs4_only(target, transport, dom, element)
+    except Exception:
+        util.SMlog("Unable to scan exports with NFSv4 pseudo FS mount")
+
+    raise NfsException("Failed to read NFS export paths from server %s" %
+                           (target))
 
-def scan_srlist(path, dconf):
+def scan_srlist(path, transport, dconf):
     """Scan and report SR, UUID."""
     dom = xml.dom.minidom.Document()
     element = dom.createElement("SRlist")
@@ -243,7 +290,7 @@ def scan_srlist(path, dconf):
     if dconf.has_key(PROBEVERSION):
         util.SMlog("Add supported nfs versions to sr-probe")
         try:
-            supported_versions = get_supported_nfs_versions(dconf.get('server'))
+            supported_versions = get_supported_nfs_versions(dconf.get('server'), transport)
             supp_ver = dom.createElement("SupportedVersions")
             element.appendChild(supp_ver)
 
@@ -259,21 +306,53 @@ def scan_srlist(path, dconf):
     return dom.toprettyxml()
 
 
-def get_supported_nfs_versions(server):
-    """Return list of supported nfs versions."""
-    valid_versions = set(['3', '4'])
+def _get_supported_nfs_version_rpcinfo(server):
+    """ Return list of supported nfs versions.
+        Using NFS3 services.
+    """
+
+    valid_versions = set(["3", "4"])
+    cv = set()
+    ns = util.pread2([RPCINFO_BIN, "-s", "%s" % server])
+    ns = ns.split("\n")
+    for i in range(len(ns)):
+        if ns[i].find("nfs") > 0:
+            cvi = ns[i].split()[1].split(",")
+            for j in range(len(cvi)):
+                cv.add(cvi[j])
+    return sorted(cv & valid_versions)
+
+
+def _is_nfs4_supported(server, transport):
+    """ Return list of supported nfs versions.
+        Using NFS4 pseudo FS.
+    """
+
     cv = set()
     try:
-        ns = util.pread2([RPCINFO_BIN, "-p", "%s" % server])
-        ns = ns.split("\n")
-        for i in range(len(ns)):
-            if ns[i].find("nfs") > 0:
-                cvi = ns[i].split()[1]
-                cv.add(cvi)
-        return list(cv & valid_versions)
-    except:
-        util.SMlog("Unable to obtain list of valid nfs versions")
-        raise NfsException('Failed to read supported NFS version from server %s' %
+        mountpoint = "%s/%s" % (NFS4_TMP_MOUNTPOINT, server)
+        soft_mount(mountpoint, server, NFS4_PSEUDOFS, transport, nfsversion='4')
+        util.pread2([NFS_STAT, "-m"])
+        unmount(mountpoint, NFS4_PSEUDOFS)
+        return True
+    except Exception:
+        return False
+
+
+def get_supported_nfs_versions(server, transport):
+    """Return list of supported nfs versions."""
+    try:
+        return _get_supported_nfs_version_rpcinfo(server)
+    except Exception:
+        util.SMlog("Unable to obtain list of valid nfs versions with %s, trying NFSv4" % RPCINFO_BIN)
+
+    # NFSv4 only
+    if _is_nfs4_supported(server, transport):
+        return ["4"]
+    else:
+        util.SMlog("Unable to obtain list of valid nfs versions with NFSv4 pseudo FS mount")
+
+    raise NfsException("Failed to read supported NFS version from server %s" %
                            (server))
 
 def get_nfs_timeout(other_config):

tests/test_NFSSR.py

@@ -182,7 +182,7 @@ def test_attach(self, validate_nfsversion, check_server_tcp, _testhost,
 
         nfssr.attach(None)
 
-        check_server_tcp.assert_called_once_with('aServer',
+        check_server_tcp.assert_called_once_with('aServer', 'tcp',
                                                  'aNfsversionChanged')
         soft_mount.assert_called_once_with('/var/run/sr-mount/UUID',
                                            'aServer',

tests/test_nfs.py

@@ -9,31 +9,32 @@ class Test_nfs(unittest.TestCase):
 
     @mock.patch('util.pread', autospec=True)
     def test_check_server_tcp(self, pread):
-        nfs.check_server_tcp('aServer')
+        nfs.check_server_tcp('aServer', 'tcp')
 
-        pread.assert_called_once_with(['/usr/sbin/rpcinfo', '-p', 'aServer'], quiet=False)
+        pread.assert_called_once_with(['/usr/sbin/rpcinfo', '-s', 'aServer'], quiet=False)
 
     @mock.patch('util.pread', autospec=True)
     def test_check_server_tcp_nfsversion(self, pread):
-        nfs.check_server_tcp('aServer', 'aNfsversion')
+        nfs.check_server_tcp('aServer', 'tcp', 'aNfsversion')
 
-        pread.assert_called_once_with(['/usr/sbin/rpcinfo', '-p', 'aServer'], quiet=False)
+        pread.assert_called_once_with(['/usr/sbin/rpcinfo', '-s', 'aServer'], quiet=False)
 
     @mock.patch('util.pread', autospec=True)
     def test_check_server_tcp_nfsversion_error(self, pread):
         pread.side_effect = util.CommandException
 
         with self.assertRaises(nfs.NfsException):
-            nfs.check_server_tcp('aServer', 'aNfsversion')
+            nfs.check_server_tcp('aServer', 'tcp', 'aNfsversion')
 
-        pread.assert_called_once_with(['/usr/sbin/rpcinfo', '-p', 'aServer'], quiet=False)
+        self.assertEqual(len(pread.mock_calls), 2)
 
     @mock.patch('time.sleep', autospec=True)
+    @mock.patch('nfs.get_supported_nfs_versions', autospec=True)
     # Can't use autospec due to http://bugs.python.org/issue17826
     @mock.patch('util.pread')
-    def test_check_server_service(self, pread, sleep):
+    def test_check_server_service(self, pread, get_supported_nfs_versions, sleep):
         pread.side_effect=["    100003  4,3,2     udp6,tcp6,udp,tcp                nfs         superuser"]
-        service_found = nfs.check_server_service('aServer')
+        service_found = nfs.check_server_service('aServer', 'tcp')
 
         self.assertTrue(service_found)
         self.assertEqual(len(pread.mock_calls), 1)
@@ -48,7 +49,7 @@ def test_check_server_service_with_retries(self, pread, sleep):
         pread.side_effect=["",
                            "",
                            "    100003  4,3,2     udp6,tcp6,udp,tcp                nfs         superuser"]
-        service_found = nfs.check_server_service('aServer')
+        service_found = nfs.check_server_service('aServer', 'tcp')
 
         self.assertTrue(service_found)
         self.assertEqual(len(pread.mock_calls), 3)
@@ -59,26 +60,28 @@ def test_check_server_service_with_retries(self, pread, sleep):
     def test_check_server_service_not_available(self, pread, sleep):
         pread.return_value=""
 
-        service_found = nfs.check_server_service('aServer')
+        service_found = nfs.check_server_service('aServer', 'tcp')
 
         self.assertFalse(service_found)
 
     @mock.patch('time.sleep', autospec=True)
+    @mock.patch('nfs.get_supported_nfs_versions', autospec=True)
     # Can't use autospec due to http://bugs.python.org/issue17826
     @mock.patch('util.pread')
-    def test_check_server_service_exception(self, pread, sleep):
+    def test_check_server_service_exception(self, pread, get_supported_nfs_versions, sleep):
         pread.side_effect=[util.CommandException(errno.ENOMEM)]
         with self.assertRaises(util.CommandException):
-            nfs.check_server_service('aServer')
+            nfs.check_server_service('aServer', 'tcp')
 
 
     @mock.patch('time.sleep', autospec=True)
+    @mock.patch('nfs.get_supported_nfs_versions', autospec=True)
     # Can't use autospec due to http://bugs.python.org/issue17826
     @mock.patch('util.pread')
-    def test_check_server_service_first_call_exception(self, pread, sleep):
+    def test_check_server_service_first_call_exception(self, pread, get_supported_nfs_versions, sleep):
         pread.side_effect=[util.CommandException(errno.EPIPE),
                             "    100003  4,3,2     udp6,tcp6,udp,tcp                nfs         superuser"]
-        service_found = nfs.check_server_service('aServer')
+        service_found = nfs.check_server_service('aServer', 'tcp')
 
         self.assertTrue(service_found)
         self.assertEqual(len(pread.mock_calls), 2)
@@ -88,37 +91,29 @@ def get_soft_mount_pread(self, binary, vers):
                  'soft,proto=transport,vers=%s,acdirmin=0,acdirmax=0' % vers])
 
     @mock.patch('util.makedirs', autospec=True)
-    @mock.patch('nfs.check_server_service', autospec=True)
     @mock.patch('util.pread', autospec=True)
-    def test_soft_mount(self, pread, check_server_service, makedirs):
+    def test_soft_mount(self, pread, makedirs):
         nfs.soft_mount('mountpoint', 'remoteserver', 'remotepath', 'transport',
                        timeout=None)
 
-        check_server_service.assert_called_once_with('remoteserver')
         pread.assert_called_once_with(self.get_soft_mount_pread('mount.nfs',
                                                                 '3'))
 
     @mock.patch('util.makedirs', autospec=True)
-    @mock.patch('nfs.check_server_service', autospec=True)
     @mock.patch('util.pread', autospec=True)
-    def test_soft_mount_nfsversion_3(self, pread, 
-                                     check_server_service, makedirs):
+    def test_soft_mount_nfsversion_3(self, pread, makedirs):
         nfs.soft_mount('mountpoint', 'remoteserver', 'remotepath', 'transport',
                        timeout=None, nfsversion='3')
 
-        check_server_service.assert_called_once_with('remoteserver')
         pread.assert_called_with(self.get_soft_mount_pread('mount.nfs',
                                                                 '3'))
 
     @mock.patch('util.makedirs', autospec=True)
-    @mock.patch('nfs.check_server_service', autospec=True)
     @mock.patch('util.pread', autospec=True)
-    def test_soft_mount_nfsversion_4(self, pread, 
-                                     check_server_service, makedirs):
+    def test_soft_mount_nfsversion_4(self, pread, makedirs):
         nfs.soft_mount('mountpoint', 'remoteserver', 'remotepath', 'transport',
                        timeout=None, nfsversion='4')
 
-        check_server_service.assert_called_once_with('remoteserver')
         pread.assert_called_with(self.get_soft_mount_pread('mount.nfs4',
                                                                 '4'))
 
@@ -145,7 +140,7 @@ def test_validate_nfsversion_valid(self):
     @mock.patch('util.pread2')
     def test_scan_exports(self, pread2):
         pread2.side_effect = ["/srv/nfs\n/srv/nfs2 *\n/srv/nfs3 127.0.0.1/24"]
-        res = nfs.scan_exports('aServer')
+        res = nfs.scan_exports('aServer', 'tcp')
 
         expected = """<?xml version="1.0" ?>
 <nfs-exports>