add optional device argument

Author: chapmanjacobd

bin/btrfs-blockgroup-report

@@ -40,13 +40,19 @@ def parse_args():
     parser = argparse.ArgumentParser()
     parser.add_argument(
         '--usage',
+        '-u',
         action="store_true",
         help="Print device blockgroup usage",
     )
     parser.add_argument(
         'mountpoint',
         help="Btrfs filesystem mountpoint",
     )
+    parser.add_argument(
+        'device',
+        nargs='*',
+        help="Only use specific devices (default include all)",
+    )
     return parser.parse_args()
 
 
@@ -60,9 +66,17 @@ def safe_get_block_group(t):
 
 def report_usage(args):
     with btrfs.FileSystem(args.mountpoint) as fs:
+        fs_chunks = list(fs.chunks())
+
         devices = fs.devices()
         devids = [d.devid for d in devices]
-        fs_chunks = list(fs.chunks())
+        if args.device:
+            dev_infos = [fs.dev_info(id) for id in devids]
+            selected_devids = []
+            for dev in dev_infos:
+                if any(d in (dev.path, dev.devid) for d in args.device):
+                    selected_devids.append(dev.devid)
+            devids = selected_devids
 
         print(args.mountpoint, '\t', fs.usage().virtual_used_str, '\t', len(fs_chunks), 'fs chunks')
         for devid in devids: