Added support for user defined values in fstab

- Allows to set prefered spec type in fstab by either setting
blivet.fstab.spec_type for 'global' effect or device.format.fstab.spec_type for individual device.
Allowed values are "UUID", "PARTUUID", "LABEL", "PARTLABEL" or "PATH".
When selected value is not available, it uses other one (defaults to
UUID).

- Allows to set freq, passno and mntops for individual devices to be
  written in fstab. Done by setting device.format.fstab.freq/passno/mntops values respectively.

blivet/formats/fs.py

@@ -49,6 +49,7 @@
 from . import DeviceFormat, register_device_format
 from .. import util
 from ..flags import flags
+from ..fstab import FSTabOptions
 from ..storage_log import log_exception_info, log_method_call
 from .. import arch
 from ..size import Size, ROUND_UP
@@ -121,6 +122,8 @@ def __init__(self, **kwargs):
 
         DeviceFormat.__init__(self, **kwargs)
 
+        self.fstab = FSTabOptions()
+
         # Create task objects
         self._fsck = self._fsck_class(self)
         self._mkfs = self._mkfs_class(self)

blivet/fstab.py

@@ -28,6 +28,22 @@
 import logging
 log = logging.getLogger("blivet")
 
+class FSTabOptions(object):
+    """ User prefered fstab settings object intended to be attached to device.format.
+        Set variables override otherwise automatically obtained values put into fstab.
+    """
+
+    def __init__(self):
+        self.freq = None
+        self.passno = None
+
+        # prefered spec identification type; default "UUID"
+        # possible values: None, "UUID", "LABEL", "PARTLABEL", "PARTUUID", "PATH"
+        self.spec_type = None
+
+        # list of fstab options to be used
+        self.mntops = []
+
 
 class FSTabEntry(object):
     """ One processed line of fstab
@@ -277,6 +293,10 @@ def __init__(self, src_file=None, dest_file=None):
         self.src_file = src_file
         self.dest_file = dest_file
 
+        # prefered spec identification type; default "UUID"
+        # possible values: None, "UUID", "LABEL", "PARTLABEL", "PARTUUID", "PATH"
+        self.spec_type = None
+
         if self.src_file is not None:
             self.read(self.src_file)
 
@@ -535,7 +555,7 @@ def add_entry(self, spec=None, file=None, vfstype=None, mntops=None,
             _entry.freq = 0
 
         if passno is not None:
-            _entry.passno = freq
+            _entry.passno = passno
         elif _entry.passno is None:
             # 'passno' represents order of fsck run at the boot time (default: 0, i.e. disabled).
             # '/' should have 1, other checked should have 2
@@ -664,6 +684,34 @@ def find_entry(self, spec=None, file=None, *, entry=None):
 
         return None
 
+    def get_spec(self, device):
+        """ Resolve which device spec should be used and return it in a form accepted by fstab.
+            Returns None if desired spec was not found
+        """
+
+        # Use device specific spec type if it is set
+        # Use "globally" set (on FSTabManager level) spec type otherwise
+
+        spec = None
+        spec_type = device.format.fstab.spec_type or self.spec_type
+
+        if spec_type == "LABEL" and device.format.label:
+            spec = "LABEL=%s" % device.format.label
+        elif spec_type == "PARTUUID" and device.uuid:
+            spec = "PARTUUID=%s" % device.uuid
+        elif spec_type == "PARTLABEL" and device.format.name:
+            spec = "PARTLABEL=%s" % device.format.name
+        elif spec_type == "PATH":
+            spec = device.path
+        elif device.format.uuid:
+            # default choice
+            spec = "UUID=%s" % device.format.uuid
+        else:
+            # if everything else failed, let blivet decide
+            return None
+
+        return spec
+
     def update(self, action, bae_entry):
         """ Update fstab based on action type and device. Does not commit changes to a file.
 
@@ -691,20 +739,51 @@ def update(self, action, bae_entry):
             # make sure it is not already present there
             entry = self.entry_from_device(action.device)
             found = self.find_entry(entry=entry)
+
+            # get correct spec type to use (if None, the one already present in entry is used)
+            spec = self.get_spec(action.device)
+
             if found is None and action.device.format.mountpoint is not None:
                 # device is not present in fstab and has a defined mountpoint => add it
-                self.add_entry(entry=entry)
+                self.add_entry(spec=spec,
+                               mntops=action.device.format.fstab.mntops,
+                               freq=action.device.format.fstab.freq,
+                               passno=action.device.format.fstab.passno,
+                               entry=entry)
+            elif found and found.spec != spec and action.device.format.mountpoint is not None:
+                # allow change of spec of existing devices
+                self.remove_entry(entry=found)
+                self.add_entry(spec=spec,
+                               mntops=action.device.format.fstab.mntops,
+                               freq=action.device.format.fstab.freq,
+                               passno=action.device.format.fstab.passno,
+                               entry=found)
             elif found and found.file != action.device.format.mountpoint and action.device.format.mountpoint is not None:
                 # device already exists in fstab but with a different mountpoint => add it
-                self.add_entry(file=action.device.format.mountpoint, entry=found)
+                self.add_entry(spec=spec,
+                               file=action.device.format.mountpoint,
+                               mntops=action.device.format.fstab.mntops,
+                               freq=action.device.format.fstab.freq,
+                               passno=action.device.format.fstab.passno,
+                               entry=found)
             return
 
         if action.is_configure and action.is_format and bae_entry is not None:
             # Handle change of the mountpoint:
             # Change its value if it is defined, remove the fstab entry if it is None
+
             entry = self.entry_from_device(action.device)
+
+            # get correct spec type to use (if None, the one already present in entry is used)
+            spec = self.get_spec(action.device)
+
             if action.device.format.mountpoint is not None and bae_entry.file != action.device.format.mountpoint:
                 self.remove_entry(entry=bae_entry)
-                self.add_entry(file=action.device.format.mountpoint, entry=bae_entry)
+                self.add_entry(spec=spec,
+                               file=action.device.format.mountpoint,
+                               mntops=action.device.format.fstab.mntops,
+                               freq=action.device.format.fstab.freq,
+                               passno=action.device.format.fstab.passno,
+                               entry=bae_entry)
             elif action.device.format.mountpoint is None:
                 self.remove_entry(entry=bae_entry)

tests/storage_tests/fstab_test.py

@@ -64,6 +64,12 @@ def test_fstab(self):
                                      parents=[vg], name="blivetTestLVMine")
             self.storage.create_device(lv)
 
+            # specify device spec representation in fstab
+            lv.format.fstab.spec_type="PATH"
+            lv.format.fstab.freq=54321
+            lv.format.fstab.passno=12345
+            lv.format.fstab.mntops=['optionA', 'optionB']
+
             # Change the mountpoint, make sure the change will make it into the fstab
             ac = blivet.deviceaction.ActionConfigureFormat(device=lv, attr="mountpoint", new_value="/mnt/test2")
             self.storage.devicetree.actions.add(ac)
@@ -75,7 +81,9 @@ def test_fstab(self):
             with open(fstab_path, "r") as f:
                 contents = f.read()
                 self.assertTrue("blivetTestLVMine" in contents)
-                self.assertTrue("/mnt/test2" in contents)
+                self.assertTrue("54321" in contents)
+                self.assertTrue("12345" in contents)
+                self.assertTrue("optionA,optionB" in contents)
 
             dev = self.storage.devicetree.get_device_by_name("blivetTestVG-blivetTestLVMine")
             self.storage.recursive_remove(dev)
@@ -89,12 +97,4 @@ def test_fstab(self):
                 self.assertFalse("blivetTestLVMine" in contents)
                 self.assertFalse("/mnt/test2" in contents)
 
-    def test_get_device(self):
-        disk = self.storage.devicetree.get_device_by_path(self.vdevs[0])
-        self.assertIsNotNone(disk)
-
-        with tempfile.TemporaryDirectory() as tmpdirname:
-            fstab_path = os.path.join(tmpdirname, 'fstab')
 
-            # change write path of blivet.fstab
-            self.storage.fstab.dest_file = fstab_path