Resolve multipath dm devices to underlying sd devices for ZFS pool map

services/zfs.py

@@ -2,6 +2,7 @@ import asyncio
 import os
 import logging
 import re
+from pathlib import Path
 
 logger = logging.getLogger(__name__)
 
@@ -70,16 +71,71 @@ async def get_zfs_pool_map() -> dict[str, dict]:
                 parts = stripped.split()
                 dev_path = parts[0]
                 try:
-                    real = os.path.realpath(dev_path)
-                    dev_name = os.path.basename(real)
-                    # Strip partition numbers (sda1 -> sda)
-                    dev_name = re.sub(r'\d+$', '', dev_name)
-                    pool_map[dev_name] = {
+                    info = {
                         "pool": current_pool,
                         "vdev": current_vdev or current_pool,
                     }
+                    # Resolve symlink and map the device
+                    real = os.path.realpath(dev_path)
+                    dev_name = os.path.basename(real)
+
+                    # Map the resolved device (strip partition suffix)
+                    base_dev = _strip_partition(dev_name)
+                    pool_map[base_dev] = info
+
+                    # For device-mapper (multipath), also map the
+                    # underlying slave sd devices.
+                    if base_dev.startswith("dm-"):
+                        for slave in _resolve_dm_slaves(base_dev):
+                            pool_map[slave] = info
                 except Exception:
                     pass
     except FileNotFoundError:
         logger.debug("zpool not available")
     return pool_map
+
+
+def _strip_partition(dev_name: str) -> str:
+    """Strip partition suffix from a device name.
+
+    sda1 -> sda, nvme0n1p1 -> nvme0n1, dm-14 stays dm-14 (it's a
+    separate dm device for the partition, resolve via slaves).
+    """
+    # dm devices: partition dm devices are separate dm-N entries,
+    # resolve via /sys/block/dm-N/slaves to find parent dm device
+    if dev_name.startswith("dm-"):
+        parent = _get_dm_parent(dev_name)
+        return parent if parent else dev_name
+
+    # NVMe: nvme0n1p1 -> nvme0n1
+    m = re.match(r'^(nvme\d+n\d+)p\d+$', dev_name)
+    if m:
+        return m.group(1)
+
+    # Standard: sda1 -> sda
+    return re.sub(r'\d+$', '', dev_name)
+
+
+def _get_dm_parent(dm_name: str) -> str | None:
+    """For a dm partition device, find the parent dm device via slaves."""
+    slave_dir = Path(f"/sys/block/{dm_name}/slaves")
+    if slave_dir.is_dir():
+        slaves = list(slave_dir.iterdir())
+        if len(slaves) == 1 and slaves[0].name.startswith("dm-"):
+            return slaves[0].name
+    return None
+
+
+def _resolve_dm_slaves(dm_name: str) -> list[str]:
+    """Get underlying sd device names for a device-mapper device."""
+    slaves = []
+    slave_dir = Path(f"/sys/block/{dm_name}/slaves")
+    if slave_dir.is_dir():
+        for s in slave_dir.iterdir():
+            name = s.name
+            if name.startswith("dm-"):
+                # Nested dm — recurse
+                slaves.extend(_resolve_dm_slaves(name))
+            else:
+                slaves.append(name)
+    return slaves