grub_plugin virtualfs_plugin: only mount virtual filesystems once

The grub_plugin mounts a subset of the filesystems mounted by the
virtualfs_plugin. When `vmdb2` is run on Docker for Mac and
virtualfs_plugin and grub_plugin are both used, the rootfs cannot be
unmounted during teardown because some virtualfs mounts have been
mounted twice but only unmounted once. This results in leaked
device-mapper entries after each execution of `vmdb2`

To fix this issue, these plugins now only mount filesystems that
have not already been mounted.

2 files changed, 12 insertions, 6 deletions

diff --git a/vmdb/plugins/grub_plugin.py b/vmdb/plugins/grub_plugin.py
index a0d8479..1bfdda8 100644
--- a/vmdb/plugins/grub_plugin.py
+++ b/vmdb/plugins/grub_plugin.py
@@ -341,14 +341,17 @@ class GrubStepRunner(vmdb.StepRunnerInterface):
 
     def mount(self, chroot, path, mount_point, state, mount_opts=None):
         chroot_path = self.chroot_path(chroot, mount_point)
-        if not os.path.exists(chroot_path):
-            os.makedirs(chroot_path)
+        if os.path.ismount(chroot_path):
+            logging.debug("already mounted: %s", chroot_path)
+        else:
+            if not os.path.exists(chroot_path):
+                os.makedirs(chroot_path)
 
-        if mount_opts is None:
-            mount_opts = []
+            if mount_opts is None:
+                mount_opts = []
 
-        vmdb.runcmd(["mount"] + mount_opts + [path, chroot_path])
-        state.grub_mounts.append(chroot_path)
+            vmdb.runcmd(["mount"] + mount_opts + [path, chroot_path])
+            state.grub_mounts.append(chroot_path)
 
     def chroot_path(self, chroot, path):
         return os.path.normpath(os.path.join(chroot, "." + path))
diff --git a/vmdb/plugins/virtualfs_plugin.py b/vmdb/plugins/virtualfs_plugin.py
index cddb8e7..925e10b 100644
--- a/vmdb/plugins/virtualfs_plugin.py
+++ b/vmdb/plugins/virtualfs_plugin.py
@@ -56,6 +56,9 @@ class VirtualFilesystemMountStepRunner(vmdb.StepRunnerInterface):
 
         for device, mount_point, fstype in self.virtuals:
             path = os.path.normpath(os.path.join(rootfs, "./" + mount_point))
+            if os.path.ismount(path):
+                logging.debug("already mounted: %s", path)
+                continue
             if not os.path.exists(path):
                 os.mkdir(path)
             vmdb.runcmd(["mount", "-t", fstype, device, path])