[Nbd] NBD_CMD_FLAG_FUA?

[Folkert van Heusden <folkert@...421...>]

Hi,

>From the patch:
  +bit 3 - NBD_FLAG_SEND_FUA
  +should be set to 1 if the server supports the NBD_CMD_FLAG_FUA flag
  ...
  +Bits 16 and above of the commands are reserved for flags.  Right
  +now, the only flag is NBD_CMD_FLAG_FUA (bit 16), "Force unit access".

My questions:
- does it mean that I should mask of the upper 16 bit of a command and
only look at the lower 16?
- does it mean that if bit 16 bit is set, NBD_CMD_FLAG_FUA should be performed?
- what on earth is NBD_CMD_FLAG_FUA for? what should I do if i receive
that message?


Folkert.