cc_mounts: Do not add devices to fstab that are already present.

Do not add new entries to /etc/fstab for devices that already have an
existing fstab entry.

Resolves: rhbz#1542578

2 files changed, 36 insertions, 21 deletions

diff --git a/cloudinit/config/cc_mounts.py b/cloudinit/config/cc_mounts.py
index b3b25c3b..eca6ea3f 100644
--- a/cloudinit/config/cc_mounts.py
+++ b/cloudinit/config/cc_mounts.py
@@ -76,6 +76,7 @@ DEVICE_NAME_FILTER = r"^([x]{0,1}[shv]d[a-z][0-9]*|sr[0-9]+)$"
 DEVICE_NAME_RE = re.compile(DEVICE_NAME_FILTER)
 WS = re.compile("[%s]+" % (whitespace))
 FSTAB_PATH = "/etc/fstab"
+MNT_COMMENT = "comment=cloudconfig"
 
 LOG = logging.getLogger(__name__)
 
@@ -327,6 +328,22 @@ def handle(_name, cfg, cloud, log, _args):
 
     LOG.debug("mounts configuration is %s", cfgmnt)
 
+    fstab_lines = []
+    fstab_devs = {}
+    fstab_removed = []
+
+    for line in util.load_file(FSTAB_PATH).splitlines():
+        if MNT_COMMENT in line:
+            fstab_removed.append(line)
+            continue
+
+        try:
+            toks = WS.split(line)
+        except Exception:
+            pass
+        fstab_devs[toks[0]] = line
+        fstab_lines.append(line)
+
     for i in range(len(cfgmnt)):
         # skip something that wasn't a list
         if not isinstance(cfgmnt[i], list):
@@ -336,12 +353,17 @@ def handle(_name, cfg, cloud, log, _args):
 
         start = str(cfgmnt[i][0])
         sanitized = sanitize_devname(start, cloud.device_name_to_device, log)
+        if sanitized != start:
+            log.debug("changed %s => %s" % (start, sanitized))
+
         if sanitized is None:
             log.debug("Ignoring nonexistent named mount %s", start)
             continue
+        elif sanitized in fstab_devs:
+            log.info("Device %s already defined in fstab: %s",
+                     sanitized, fstab_devs[sanitized])
+            continue
 
-        if sanitized != start:
-            log.debug("changed %s => %s" % (start, sanitized))
         cfgmnt[i][0] = sanitized
 
         # in case the user did not quote a field (likely fs-freq, fs_passno)
@@ -373,11 +395,17 @@ def handle(_name, cfg, cloud, log, _args):
     for defmnt in defmnts:
         start = defmnt[0]
         sanitized = sanitize_devname(start, cloud.device_name_to_device, log)
+        if sanitized != start:
+            log.debug("changed default device %s => %s" % (start, sanitized))
+
         if sanitized is None:
             log.debug("Ignoring nonexistent default named mount %s", start)
             continue
-        if sanitized != start:
-            log.debug("changed default device %s => %s" % (start, sanitized))
+        elif sanitized in fstab_devs:
+            log.debug("Device %s already defined in fstab: %s",
+                      sanitized, fstab_devs[sanitized])
+            continue
+
         defmnt[0] = sanitized
 
         cfgmnt_has = False
@@ -409,31 +437,18 @@ def handle(_name, cfg, cloud, log, _args):
         log.debug("No modifications to fstab needed")
         return
 
-    comment = "comment=cloudconfig"
     cc_lines = []
     needswap = False
     dirs = []
     for line in actlist:
         # write 'comment' in the fs_mntops, entry,  claiming this
-        line[3] = "%s,%s" % (line[3], comment)
+        line[3] = "%s,%s" % (line[3], MNT_COMMENT)
         if line[2] == "swap":
             needswap = True
         if line[1].startswith("/"):
             dirs.append(line[1])
         cc_lines.append('\t'.join(line))
 
-    fstab_lines = []
-    removed = []
-    for line in util.load_file(FSTAB_PATH).splitlines():
-        try:
-            toks = WS.split(line)
-            if toks[3].find(comment) != -1:
-                removed.append(line)
-                continue
-        except Exception:
-            pass
-        fstab_lines.append(line)
-
     for d in dirs:
         try:
             util.ensure_dir(d)
@@ -441,7 +456,7 @@ def handle(_name, cfg, cloud, log, _args):
             util.logexc(log, "Failed to make '%s' config-mount", d)
 
     sadds = [WS.sub(" ", n) for n in cc_lines]
-    sdrops = [WS.sub(" ", n) for n in removed]
+    sdrops = [WS.sub(" ", n) for n in fstab_removed]
 
     sops = (["- " + drop for drop in sdrops if drop not in sadds] +
             ["+ " + add for add in sadds if add not in sdrops])
diff --git a/cloudinit/tests/helpers.py b/cloudinit/tests/helpers.py
index 117a9cfe..07059fd4 100644
--- a/cloudinit/tests/helpers.py
+++ b/cloudinit/tests/helpers.py
@@ -111,12 +111,12 @@ class TestCase(unittest2.TestCase):
         super(TestCase, self).setUp()
         self.reset_global_state()
 
-    def add_patch(self, target, attr, **kwargs):
+    def add_patch(self, target, attr, *args, **kwargs):
         """Patches specified target object and sets it as attr on test
         instance also schedules cleanup"""
         if 'autospec' not in kwargs:
             kwargs['autospec'] = True
-        m = mock.patch(target, **kwargs)
+        m = mock.patch(target, *args, **kwargs)
         p = m.start()
         self.addCleanup(m.stop)
         setattr(self, attr, p)