targets: move _resolve_mntdev() out of TargetSSHLVM

Make it a standalone function, it does not need anything from the class.

1 files changed, 37 insertions, 36 deletions

diff --git a/lbup/targets.py b/lbup/targets.py
index c6d7df8..877f3d7 100644
--- a/lbup/targets.py
+++ b/lbup/targets.py
@@ -35,6 +35,42 @@ def _parse_name(name):
 
     return SSHRemote(host, port, username)
 
+def _resolve_mntdev(mntinfo, dirs):
+    """
+    Find the device on which dirs to back up are located.
+
+    This also checks that all the dirs are on the same mount and no non-trivial
+    topologies (like bind mounts) are involved,
+    otherwise a BackupException is raised.
+
+    Return a tuple of (devnum, mountpoint, fstype)
+    """
+    devnum     = None
+    mountpoint = None
+    fstype     = None
+    for d in dirs:
+        mp = mntinfo.mountpoint_for_path(d)
+        e  = list(mntinfo.entries_for_mountpoint(mp))
+
+        if len(e) != 1:
+            raise BackupException('Expected exactly one mountpoint for dir', d, str(e))
+        if e[0].root != ROOT:
+            raise BackupException('Mountpoint is a bind mount, which is not supported', str(e[0]))
+        dn = e[0].devnum
+
+        if devnum is None:
+            devnum     = dn
+            mountpoint = mp
+            fstype     = e[0].fstype
+            continue
+
+        if dn != devnum or mp != mountpoint:
+            raise BackupException('Mismatching device numbers/mountpoints',
+                    dn, devnum, mp, mountpoint)
+
+    return (devnum, mountpoint, fstype)
+
+
 class Target(ABC):
     name     = None
     dirs     = None
@@ -235,41 +271,6 @@ class TargetSSHLVM(TargetSSH):
         """
         return 1
 
-    def _resolve_mntdev(self, mntinfo, dirs):
-        """
-        Find out which LV to snapshot.
-
-        This also checks that all the dirs are on the same LV and no non-trivial
-        topologies (like bind mounts) are involved,
-        otherwise a BackupException is raised.
-
-        Return a tuple of (devnum, mountpoint)
-        """
-        devnum     = None
-        mountpoint = None
-        fstype     = None
-        for d in dirs:
-            mp = mntinfo.mountpoint_for_path(d)
-            e  = list(mntinfo.entries_for_mountpoint(mp))
-
-            if len(e) != 1:
-                raise BackupException('Expected exactly one mountpoint for dir', d, str(e))
-            if e[0].root != ROOT:
-                raise BackupException('Mountpoint is a bind mount, which is not supported', str(e[0]))
-            dn = e[0].devnum
-
-            if devnum is None:
-                devnum     = dn
-                mountpoint = mp
-                fstype     = e[0].fstype
-                continue
-
-            if dn != devnum or mp != mountpoint:
-                raise BackupException('Mismatching device numbers/mountpoints',
-                        dn, devnum, mp, mountpoint)
-
-        return (devnum, mountpoint, fstype)
-
     def _resolve_lv(self, ssh, devnum):
         """
         Find the logical volume for the given device number.
@@ -364,7 +365,7 @@ class TargetSSHLVM(TargetSSH):
                 self._paramiko_exec_cmd(conn_root, 'cat /proc/%d/mountinfo' % self._mntns_pid,
                                         decode = False))
 
-            devnum, mountpoint, fstype = self._resolve_mntdev(mntinfo, dirs)
+            devnum, mountpoint, fstype = _resolve_mntdev(mntinfo, dirs)
 
             # make sure we have a valid fstype
             fstype = fstype.decode('ascii')