[fstab] Replace two-step attribute-setting with one step

- do not use subprocess module in Python bits,
- do +C (no-CoW) after turning compression off

CHANGES-3.2

@@ -8,6 +8,14 @@ contributors are listed. Note that Calamares does not have a historical
 changelog -- this log starts with version 3.2.0. The release notes on the
 website will have to do for older versions.
 
+# 3.2.58.2 (2022-05-24)
+
+This is a extra-quick release for an issue that shows up when using a
+swap **file** on a btrfs filesystem; the installation would fail with
+a Python error, raised from btrfs-progs. Reported by Evan James, Erik
+Dubois, TechXero.
+
+
 # 3.2.58.1 (2022-05-20)
 
 This is a hot-fix release for a regression in the *partition* module where

CMakeLists.txt

@@ -41,7 +41,7 @@
 # TODO:3.3: Require CMake 3.12
 cmake_minimum_required( VERSION 3.3 FATAL_ERROR )
 project( CALAMARES
-    VERSION 3.2.58.1
+    VERSION 3.2.58.2
     LANGUAGES C CXX
 )
 

src/modules/fstab/main.py

@@ -173,7 +173,6 @@ class FstabGenerator(object):
                    for p in self.partitions]):
                 password = "none"
                 crypttab_options = ""
-        
 
         return dict(
             name=mapper_name,
@@ -342,10 +341,7 @@ def create_swapfile(root_mount_point, root_btrfs):
         swapfile_path = os.path.join(root_mount_point, "swap/swapfile")
         with open(swapfile_path, "wb") as f:
             pass
-        o = subprocess.check_output(["chattr", "+C", swapfile_path])
-        libcalamares.utils.debug("swapfile attributes: {!s}".format(o))
-        o = subprocess.check_output(["btrfs", "property", "set", swapfile_path, "compression", "none"])
-        libcalamares.utils.debug("swapfile compression: {!s}".format(o))
+        libcalamares.utils.host_env_process_output(["chattr", "+C", "+m", swapfile_path])  # No Copy-on-Write, no compression
     else:
         swapfile_path = os.path.join(root_mount_point, "swapfile")
         with open(swapfile_path, "wb") as f:
@@ -363,8 +359,7 @@ def create_swapfile(root_mount_point, root_btrfs):
             libcalamares.job.setprogress(0.2 + 0.3 * ( total / desired_size ) )
             total += chunk
     os.chmod(swapfile_path, 0o600)
-    o = subprocess.check_output(["mkswap", swapfile_path])
-    libcalamares.utils.debug("swapfile mkswap: {!s}".format(o))
+    libcalamares.utils.host_env_process_output(["mkswap", swapfile_path])
     libcalamares.job.setprogress(0.5)