Initial remote commit

test/testsize.sh

@@ -0,0 +1,25 @@
+# What size does the kernel think nbd0 is?
+blockdev --getsize64 /dev/nbd0
+blockdev --getsz /dev/nbd0
+
+# What does the superblock say?
+python3 -c "
+import struct
+with open('/dev/nbd0','rb') as f:
+    f.seek(1024)
+    sb = f.read(256)
+blocks_lo = struct.unpack_from('<I',sb,4)[0]
+blocks_hi = struct.unpack_from('<I',sb,336)[0]
+total = (blocks_hi<<32)|blocks_lo
+bsize = 4096
+print(f'SB block count: {total}')
+print(f'SB filesystem size: {total*bsize} bytes')
+print(f'NBD device size: ', end='')
+import subprocess
+r = subprocess.run(['blockdev','--getsize64','/dev/nbd0'],
+                   capture_output=True,text=True)
+nbd_size = int(r.stdout.strip())
+print(nbd_size)
+print(f'Match: {total*bsize == nbd_size}')
+print(f'Difference: {abs(total*bsize - nbd_size)} bytes')
+"