[master] Allow opt-out of discard on disk format

changelog/64310.added.md

@@ -0,0 +1 @@
+Added ``discard`` parameter to ``disk.format_`` and ``blockdev.formatted`` to allow opting out of block discard during filesystem creation, preventing sparse inflation of disk images on host filesystems.

salt/modules/disk.py

@@ -481,6 +481,7 @@ def format_(
     lazy_itable_init=None,
     fat=None,
     force=False,
+    discard=True,
 ):
     """
     Format a filesystem onto a device
@@ -519,6 +520,15 @@ def format_(
 
         This option is dangerous, use it with caution.
 
+    discard
+        Attempt to discard blocks at mkfs time (enabled by default). Set to
+        ``False`` to disable block discard, which prevents sparse file
+        inflation when formatting disk images on a host filesystem.
+
+        This option is only supported for ext and xfs filesystems.
+
+        .. versionadded:: 3009.0
+
     CLI Example:
 
     .. code-block:: bash
@@ -534,6 +544,11 @@ def format_(
     if lazy_itable_init is not None:
         if fs_type[:3] == "ext":
             cmd.extend(["-E", f"lazy_itable_init={lazy_itable_init}"])
+    if not discard:
+        if fs_type[:3] == "ext":
+            cmd.extend(["-E", "nodiscard"])
+        elif fs_type == "xfs":
+            cmd.append("-K")
     if fat is not None and fat in (12, 16, 32):
         if fs_type[-3:] == "fat":
             cmd.extend(["-F", fat])

tests/pytests/unit/modules/test_disk.py

@@ -382,6 +382,34 @@ def test_format_():
         mock.assert_any_call(["mkfs", "-t", "ext4", device], ignore_retcode=True)
 
 
+@pytest.mark.skip_on_windows(reason="Skip on Windows")
+@pytest.mark.skip_if_binaries_missing("mkfs")
+def test_format__nodiscard_ext():
+    """
+    unit tests for disk.format_ with discard=False on an ext filesystem
+    """
+    device = "/dev/sdX1"
+    mock = MagicMock(return_value=0)
+    with patch.dict(disk.__salt__, {"cmd.retcode": mock}):
+        disk.format_(device=device, fs_type="ext4", discard=False)
+        mock.assert_any_call(
+            ["mkfs", "-t", "ext4", "-E", "nodiscard", device], ignore_retcode=True
+        )
+
+
+@pytest.mark.skip_on_windows(reason="Skip on Windows")
+@pytest.mark.skip_if_binaries_missing("mkfs")
+def test_format__nodiscard_xfs():
+    """
+    unit tests for disk.format_ with discard=False on an xfs filesystem
+    """
+    device = "/dev/sdX1"
+    mock = MagicMock(return_value=0)
+    with patch.dict(disk.__salt__, {"cmd.retcode": mock}):
+        disk.format_(device=device, fs_type="xfs", discard=False)
+        mock.assert_any_call(["mkfs", "-t", "xfs", "-K", device], ignore_retcode=True)
+
+
 @pytest.mark.skip_on_windows(reason="Skip on Windows")
 @pytest.mark.skip_if_binaries_missing("mkfs")
 def test_format__fat():