Merge pull request #46 from flatcar-linux/kai/flatcar-build-2387.0.0-pick

Pick commits from flatcar-master for alpha branch

build_library/disk_util

@@ -11,6 +11,7 @@ import re
 import subprocess
 import sys
 import tempfile
+import time
 import uuid
 
 # First sector we can use.
@@ -433,11 +434,22 @@ def FormatFat(part, device):
 def PartitionLoop(options, partition):
   """Allocate (and automatically free) loop devices for a partition."""
 
-  loop_dev = subprocess.check_output(['sudo', 'losetup',
-      '--offset', str(partition['first_byte']),
-      '--sizelimit', str(partition['bytes']),
-      '--find', '--show', options.disk_image])
-  loop_dev = loop_dev.strip()
+  for i in range(0,5):
+    try:
+      loop_dev = subprocess.check_output(['sudo', 'losetup',
+        '--offset', str(partition['first_byte']),
+        '--sizelimit', str(partition['bytes']),
+        '--find', '--show', options.disk_image])
+      loop_dev = loop_dev.strip()
+      err = None
+      break
+    except subprocess.CalledProcessError as error:
+      print("Failed to set up loopback, attempt %d" % i)
+      err = error
+      time.sleep(5)
+
+  if err is not None:
+    raise err
 
   try:
     yield loop_dev
@@ -586,9 +598,22 @@ def Mount(options):
       mount_opts.append('subvol=%s' % mount['fs_subvolume'])
 
     Sudo(['mkdir', '-p', full_path])
-    Sudo(['mount', '-t', mount.get('fs_type', 'auto'),
-                   '-o', ','.join(mount_opts),
-                   options.disk_image, full_path])
+    # This tends to fail, retry if it does
+    err = None
+    for i in range(0,5):
+      try:
+        Sudo(['mount', '-t', mount.get('fs_type', 'auto'),
+                       '-o', ','.join(mount_opts),
+                       options.disk_image, full_path])
+        err = None
+        break
+      except subprocess.CalledProcessError as e:
+        print("Error mounting %s, attempt %d" % (full_path, i))
+        err = e
+        time.sleep(5)
+
+    if err is not None:
+      raise err
 
     for src, dst in mount.get('binds', {}).iteritems():
       # src may be relative or absolute, os.path.join handles this.