ceph-volume: fix loop devices support

This commit updates the `is_device` function to correctly handle
loop devices.
The function now validates loop devices when they are explicitly
allowed, by checking their type (`loop`) in addition to `disk`
and `mpath`.

Changes include:
  - Extending the type check to include `loop` in the list of
    supported device types.
  - Enhancing the docstring for better documentation of the
    function's purpose and behavior.

These changes ensure that loop devices are properly recognized
and handled when configuring OSDs in ceph-volume.

Fixes: https://tracker.ceph.com/issues/69432
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>
(cherry picked from commit 013c1c666cd44fdf213612c5ef6ab8aa9373970e)

diff --git a/src/ceph-volume/ceph_volume/util/disk.py b/src/ceph-volume/ceph_volume/util/disk.py
index 47caaae6d31cc4b9a38a3b757f5b8c29261d1bfc..c2ae16dfeba11adce5434bf65b301f54bb79fab1 100644 (file)
--- a/src/ceph-volume/ceph_volume/util/disk.py
+++ b/src/ceph-volume/ceph_volume/util/disk.py
@@ -347,12 +347,21 @@ def lsblk_all(device: str = '',
     return result
 
 
-def is_device(dev):
+def is_device(dev: str) -> bool:
     """
-    Boolean to determine if a given device is a block device (**not**
-    a partition!)
+    Determines whether the given path corresponds to a block device (not a partition).
 
-    For example: /dev/sda would return True, but not /dev/sdc1
+    This function checks whether the provided device path represents a valid block device,
+    such as a physical disk (/dev/sda) or an allowed loop device, but excludes partitions
+    (/dev/sdc1). It performs several validation steps, including file existence, path format,
+    device type, and additional checks for loop devices if allowed.
+
+    Args:
+        dev (str): The path to the device (e.g., "/dev/sda").
+
+    Returns:
+        bool: True if the path corresponds to a valid block device (not a partition),
+              otherwise False.
     """
     if not os.path.exists(dev):
         return False
@@ -364,7 +373,7 @@ def is_device(dev):
 
     TYPE = lsblk(dev).get('TYPE')
     if TYPE:
-        return TYPE in ['disk', 'mpath']
+        return TYPE in ['disk', 'mpath', 'loop']
 
     # fallback to stat
     return _stat_is_device(os.lstat(dev).st_mode) and not is_partition(dev)