Merge 291f770 into c1de61a

drivers/NFSSR.py

@@ -39,7 +39,7 @@
                  ['serverpath', 'path on remote server (required)'],
                  nfs.NFS_VERSION]
 
-                  
+
 DRIVER_INFO = {
     'name': 'NFS VHD',
     'description': 'SR plugin which stores disks as VHD files on a remote NFS filesystem',

drivers/nfs.py

@@ -2,13 +2,13 @@
 #
 # Copyright (C) Citrix Systems Inc.
 #
-# This program is free software; you can redistribute it and/or modify 
-# it under the terms of the GNU Lesser General Public License as published 
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published
 # by the Free Software Foundation; version 2.1 only.
 #
-# This program is distributed in the hope that it will be useful, 
-# but WITHOUT ANY WARRANTY; without even the implied warranty of 
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public License
@@ -17,56 +17,67 @@
 #
 # nfs.py: NFS related utility functions
 
-import util, errno, os, xml.dom.minidom
+import util
+import errno
+import os
+import xml.dom.minidom
 
-# The algorithm for tcp and udp (at least in the linux kernel) for 
+# The algorithm for tcp and udp (at least in the linux kernel) for
 # NFS timeout on softmounts is as follows:
 #
 # UDP:
-# As long as the request wasn't started more than timeo * (2 ^ retrans) 
+# As long as the request wasn't started more than timeo * (2 ^ retrans)
 # in the past, keep doubling the timeout.
 #
 # TCP:
-# As long as the request wasn't started more than timeo * (1 + retrans) 
+# As long as the request wasn't started more than timeo * (1 + retrans)
 # in the past, keep increaing the timeout by timeo.
 #
 # The time when the retrans may retry has been made will be:
 # For udp: timeo * (2 ^ retrans * 2 - 1)
 # For tcp: timeo * n! where n is the smallest n for which n! > 1 + retrans
 #
-# thus for retrans=1, timeo can be the same for both tcp and udp, 
+# thus for retrans=1, timeo can be the same for both tcp and udp,
 # because the first doubling (timeo*2) is the same as the first increment
 # (timeo+timeo).
 
-SOFTMOUNT_TIMEOUT  = 60 # seconds
-SOFTMOUNT_RETRANS  = 0x7fffffff
+SOFTMOUNT_TIMEOUT = 60  # seconds
+SOFTMOUNT_RETRANS = 0x7fffffff
 RPCINFO_BIN = "/usr/sbin/rpcinfo"
 SHOWMOUNT_BIN = "/usr/sbin/showmount"
 
 DEFAULT_NFSVERSION = '3'
 
 NFS_VERSION = [
-    'nfsversion', 'for type=nfs, NFS protocol version - 3, 4 (optional)']
+    'nfsversion', 'for type=nfs, NFS protocol version - 3, 4']
 
 
 class NfsException(Exception):
+
     def __init__(self, errstr):
         self.errstr = errstr
 
 
 def check_server_tcp(server, nfsversion=DEFAULT_NFSVERSION):
-    """Make sure that NFS over TCP/IP V3 is supported on the server. 
-    Returns True if everything is OK, False otherwise."""
+    """Make sure that NFS over TCP/IP V3 is supported on the server.
+
+    Returns True if everything is OK
+    False otherwise.
+    """
     try:
-        util.ioretry(lambda: util.pread([RPCINFO_BIN,"-t", 
+        util.ioretry(lambda: util.pread([RPCINFO_BIN, "-t",
                                          "%s" % server, "nfs", nfsversion]),
                      errlist=[errno.EPERM], maxretry=2, nofail=True)
     except util.CommandException, inst:
-        raise NfsException("rpcinfo failed or timed out: return code %d" % 
+        raise NfsException("rpcinfo failed or timed out: return code %d" %
                            inst.code)
 
 
 def validate_nfsversion(nfsversion):
+    """Check the validity of 'nfsversion'.
+
+    Raise an exception for any invalid version.
+    """
     if not nfsversion:
         nfsversion = DEFAULT_NFSVERSION
     else:
@@ -78,13 +89,15 @@ def validate_nfsversion(nfsversion):
 def soft_mount(mountpoint, remoteserver, remotepath, transport, timeout=0,
                nfsversion=DEFAULT_NFSVERSION):
     """Mount the remote NFS export at 'mountpoint'.
-    The 'timeout' param here is in seconds"""
+
+    The 'timeout' param here is in seconds
+    """
     try:
         if not util.ioretry(lambda: util.isdir(mountpoint)):
             util.ioretry(lambda: util.makedirs(mountpoint))
     except util.CommandException, inst:
-        raise NfsException("Failed to make directory: code is %d" % 
-                            inst.code)
+        raise NfsException("Failed to make directory: code is %d" %
+                           inst.code)
 
     mountcommand = 'mount.nfs'
     if nfsversion == '4':
@@ -94,18 +107,18 @@ def soft_mount(mountpoint, remoteserver, remotepath, transport, timeout=0,
         timeout = SOFTMOUNT_TIMEOUT
 
     options = "soft,timeo=%d,retrans=%d,proto=%s,vers=%s" % (
-                                                             timeout * 10,
-                                                             SOFTMOUNT_RETRANS,
-                                                             transport,
-                                                             nfsversion)
+        timeout * 10,
+        SOFTMOUNT_RETRANS,
+        transport,
+        nfsversion)
     options += ',acdirmin=0,acdirmax=0'
 
     try:
-        util.ioretry(lambda: 
+        util.ioretry(lambda:
                      util.pread([mountcommand, "%s:%s"
-                                 % (remoteserver, remotepath),  
+                                 % (remoteserver, remotepath),
                                  mountpoint, "-o", options]),
-                                 errlist=[errno.EPIPE, errno.EIO], 
+                     errlist=[errno.EPIPE, errno.EIO],
                      maxretry=2, nofail=True)
     except util.CommandException, inst:
         raise NfsException("mount failed with return code %d" % inst.code)
@@ -126,6 +139,7 @@ def unmount(mountpoint, rmmountpoint):
 
 
 def scan_exports(target):
+    """Scan target and return an XML DOM with target, path and accesslist."""
     util.SMlog("scanning")
     cmd = [SHOWMOUNT_BIN, "--no-headers", "-e", target]
     dom = xml.dom.minidom.Document()
@@ -136,12 +150,12 @@ def scan_exports(target):
             continue
         entry = dom.createElement('Export')
         element.appendChild(entry)
-        
+
         subentry = dom.createElement("Target")
         entry.appendChild(subentry)
         textnode = dom.createTextNode(target)
         subentry.appendChild(textnode)
-            
+
         (path, access) = val.split()
         subentry = dom.createElement("Path")
         entry.appendChild(subentry)
@@ -155,19 +169,21 @@ def scan_exports(target):
 
     return dom
 
+
 def scan_srlist(path):
+    """Scan and report SR, UUID."""
     dom = xml.dom.minidom.Document()
     element = dom.createElement("SRlist")
     dom.appendChild(element)
-    for val in filter(util.match_uuid, util.ioretry( \
+    for val in filter(util.match_uuid, util.ioretry(
             lambda: util.listdir(path))):
         fullpath = os.path.join(path, val)
         if not util.ioretry(lambda: util.isdir(fullpath)):
             continue
-            
+
         entry = dom.createElement('SR')
         element.appendChild(entry)
-        
+
         subentry = dom.createElement("UUID")
         entry.appendChild(subentry)
         textnode = dom.createTextNode(val)