Skip LVM filesystem check on LV reduction

Since LVM v2.03.17 (lvmteam/lvm2@f6f2737), reducing a logical volume (LV) requires the LV to be active due to the default 'checksize' option, which requires an active LV. This results in the following error when attempting to reduce a non-active LV:

----
err=[\'  The LV must be active to safely reduce (see --fs options.)\']'
----

To resolve this, we now check if the LVM version is newer than 2.03.17. If so, we bypass the 'checksize' by using the '--fs ignore' option. This approach is viable because the oVirt engine already handles checksize, making lvreduce redundant.

Signed-off-by: Brooklyn Dewolf <contact@brooklyn.gent>

lib/vdsm/osinfo.py

@@ -248,6 +248,7 @@ def package_versions():
             'qemu-kvm': ('qemu-kvm', 'qemu-kvm-rhev', 'qemu-kvm-ev'),
             'spice-server': ('spice-server',),
             'vdsm': ('vdsm',),
+            'lvm2': ('lvm2', 'lvm2-libs'),
         }
 
         if glusterEnabled:
@@ -281,6 +282,7 @@ def package_versions():
             'qemu-kvm': 'qemu-kvm',
             'spice-server': 'libspice-server1',
             'vdsm': 'vdsmd',
+            'lvm2': 'lvm2',
         }
 
         if glusterEnabled:

lib/vdsm/storage/lvm.py

@@ -23,6 +23,7 @@
 
 from vdsm import constants
 from vdsm import utils
+from vdsm import osinfo
 from vdsm.common import commands
 from vdsm.common import errors
 from vdsm.common import logutils
@@ -240,6 +241,15 @@ def __getattr__(self, attrName):
 USE_DEVICES = config.get("lvm", "config_method").lower() == "devices"
 
 
+def _get_lvm_version():
+    packages = osinfo.package_versions()
+    lvm_version = tuple(
+        int(v)
+        for v in packages['lvm2']['version'].split('.')
+    )
+    return lvm_version
+
+
 def _prepare_device_set(devs):
     devices = set(d.strip() for d in chain(devs, USER_DEV_LIST))
     devices.discard('')
@@ -1781,12 +1791,15 @@ def extendLV(vgName, lvName, size_mb, refresh=True):
 
 
 def reduceLV(vgName, lvName, size_mb, force=False):
+    lvm_version = _get_lvm_version()
     log.info("Reducing LV %s/%s to %s megabytes (force=%s)",
              vgName, lvName, size_mb, force)
     cmd = ("lvreduce",) + LVM_NOBACKUP
     if force:
         cmd += ("--force",)
     cmd += ("--size", "%sm" % (size_mb,), "%s/%s" % (vgName, lvName))
+    if lvm_version >= (2, 3, 17):
+        cmd += ("--fs", "ignore")
 
     try:
         _lvminfo.run_command(cmd, devices=_lvminfo._getVGDevs((vgName,)))