ras/ras_ppcutils: Add support for multipath disk devices

Fix disk detection to handle multipath devices (e.g., /dev/mapper/mpatha).
The test uses disk_name for ofpathname and lsdevinfo commands which require
physical disk paths, not device-mapper multipath paths.

Changes:
- Added regex pattern to detect multipath device names (mpatha-part2, mpath0p1)
- Implemented multipath device resolution using 'multipath -ll' command
- Parse multipath output to extract underlying physical disk (sda, sdb, etc.)
- Added fallback to dmsetup if multipath command is unavailable
- Resolve to physical disk path before using in test commands

This fixes the "Couldn't get Disk name" error on systems using multipath
storage configurations.

Assisted by AI.
Signed-off-by: Krishan Gopal Saraswat <krishang@linux.ibm.com>

Author: Krishan Gopal Saraswat

ras/ras_ppcutils.py

@@ -67,14 +67,54 @@ def setUp(self):
                             package)
         # get the disk name
         self.disk_name = ''
+        self.is_multipath = False
         output = process.system_output("df -h", shell=True).decode().splitlines()
-        filtered_lines = [line for line in output if re.search(r'\b(sd[a-z]\d+|vd[a-z]\d+|nvme\d+n\d+p\d+)\b', line)]
+        # Match standard disks (sda1, vda1, nvme0n1p1) and multipath devices (mpatha-part2, mpath0p1)
+        filtered_lines = [line for line in output if re.search(r'\b(sd[a-z]\d+|vd[a-z]\d+|nvme\d+n\d+p\d+|mpath[a-z0-9]+-part\d+|mpath[a-z0-9]+p\d+)\b', line)]
         if filtered_lines:
             disk_entry = filtered_lines[-1].split()[0]
-            # Strip partition number: for sdX or vdX it’s trailing digits, for nvme it’s after 'p'
-            self.disk_name = re.sub(r'(\d+$|p\d+$)', '', disk_entry)
+            # Strip partition number: for sdX/vdX it's trailing digits, for nvme it's after 'p', for multipath it's after '-part' or 'p'
+            if '/dev/mapper/' in disk_entry:
+                # For multipath devices like /dev/mapper/mpatha-part2, extract mpatha
+                self.disk_name = re.sub(r'(-part\d+|p\d+)$', '', disk_entry)
+                self.is_multipath = True
+            else:
+                self.disk_name = re.sub(r'(\d+$|p\d+$)', '', disk_entry)
         if not self.disk_name:
             self.cancel("Couldn't get Disk name.")
+        
+        # For multipath devices, find the underlying physical disk
+        if self.is_multipath:
+            try:
+                # Try to get underlying disk using multipath command
+                mpath_name = self.disk_name.split('/')[-1]  # Extract mpatha from /dev/mapper/mpatha
+                mp_output = process.system_output(f"multipath -ll {mpath_name}",
+                                                  shell=True, ignore_status=True).decode()
+                # Parse multipath output to find physical disk (e.g., sda, sdb)
+                # Format: `- 1:0:0:2 sda 8:0  active ready running
+                for line in mp_output.splitlines():
+                    match = re.search(r'\s+(sd[a-z]+|vd[a-z]+|nvme\d+n\d+)\s+', line)
+                    if match:
+                        physical_disk = match.group(1).strip()
+                        self.disk_name = f"/dev/{physical_disk}"
+                        self.is_multipath = False
+                        break
+            except Exception:
+                # If multipath command fails, try dmsetup
+                try:
+                    dm_output = process.system_output(f"dmsetup deps {mpath_name}",
+                                                     shell=True, ignore_status=True).decode()
+                    # dmsetup deps output: 1 dependencies : (8, 0)
+                    # We need to find which device has this major:minor
+                    if 'dependencies' in dm_output:
+                        # Just try to find any sd* device as fallback
+                        all_disks = process.system_output("ls /dev/sd* /dev/vd* 2>/dev/null | head -1",
+                                                         shell=True, ignore_status=True).decode().strip()
+                        if all_disks:
+                            self.disk_name = all_disks.splitlines()[0]
+                            self.is_multipath = False
+                except Exception:
+                    pass
 
     @staticmethod
     def run_cmd_out(cmd):
@@ -368,11 +408,15 @@ def test_ls_vdev(self):
         self.run_cmd("ls-vdev")
         self.run_cmd("ls-vdev -h")
         self.run_cmd("ls-vdev -V")
-        dev_name = self.run_cmd_out("ls-vdev").split()[1]
-        lsblk_disks = disk.get_disks()
-        lsblk_dev_name = [i.replace('/dev/', '') for i in lsblk_disks]
-        if dev_name.strip() not in lsblk_dev_name:
-            self.is_fail += 1
+        output = self.run_cmd_out("ls-vdev").split()
+        if len(output) > 1:
+            dev_name = output[1]
+            lsblk_disks = disk.get_disks()
+            lsblk_dev_name = [i.replace('/dev/', '') for i in lsblk_disks]
+            if dev_name.strip() not in lsblk_dev_name:
+                self.is_fail += 1
+        else:
+            self.log.warning("ls-vdev returned no device information")
         if self.is_fail >= 1:
             self.fail("%s command(s) failed in ls-vdev tool "
                       "verification" % self.is_fail)
@@ -434,16 +478,21 @@ def test_bootlist(self):
             cmd = "bootlist %s" % list_item
             self.run_cmd(cmd)
         output = self.run_cmd_out("lsvio -e").splitlines()
+        interface = None
         for line in output:
             if len(line.split()) > 1:
                 interface = line.split()[1]
+                break  # Use the first valid interface found
         file_path = os.path.join(self.workdir, 'file')
         process.run("echo %s > %s" %
                     (self.disk_name, file_path), ignore_status=True,
                     sudo=True, shell=True)
-        process.run("echo %s >> %s" %
-                    (interface, file_path), ignore_status=True,
-                    sudo=True, shell=True)
+        if interface:
+            process.run("echo %s >> %s" %
+                        (interface, file_path), ignore_status=True,
+                        sudo=True, shell=True)
+        else:
+            self.log.warning("No interface found from lsvio -e, skipping interface in bootlist")
         self.run_cmd("bootlist -r -m both -f %s" % file_path)
         self.error_check()