lvol: resize filesystem when LV already has the requested size

When resizefs=true but the logical volume is already at the requested
size, run fsadm resize to ensure the filesystem fills the device.
Previously resizefs only took effect when the LV size changed

changelogs/fragments/11620-lvol-resizefs.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - lvol - ``resizefs`` now resizes the filesystem even when the logical volume already has the requested size (https://github.com/ansible-collections/community.general/issues/11620).

plugins/modules/lvol.py

@@ -90,6 +90,8 @@ options:
       - Resize the underlying filesystem together with the logical volume.
       - Supported for C(ext2), C(ext3), C(ext4), C(reiserfs) and C(XFS) filesystems. Attempts to resize other filesystem types
         result in failure.
+      - When the logical volume already has the requested size, the filesystem will still be resized to fill the logical volume
+        if needed.
     type: bool
     default: false
 notes:
@@ -662,6 +664,18 @@ def main():
                 else:
                     module.fail_json(msg=f"Unable to resize {lv} to {size}{size_unit}", rc=rc, err=err)
 
+        if resizefs and not changed and size:
+            lv_path = f"/dev/{vg}/{this_lv['name']}"
+            if module.check_mode:
+                changed = True
+            else:
+                fsadm = module.get_bin_path("fsadm", required=True)
+                rc, out, err = module.run_command([fsadm, "resize", lv_path])
+                if rc == 0:
+                    changed = True
+                else:
+                    module.fail_json(msg=f"Failed to resize filesystem on {lv_path}", rc=rc, err=err, out=out)
+
     if this_lv is not None:
         if active:
             with lvchange("active lv") as ctx: