Re: [Qemu-devel] [PATCH 00/12] nbd improvements

[Kevin Wolf <kwolf@redhat.com>]

Am 08.09.2011 17:24, schrieb Paolo Bonzini:
> I find nbd quite useful to test migration, but it is limited:
> it can only do synchronous operation, it is not safe because it
> does not support flush, and it has no discard either.  qemu-nbd
> is also limited to 1MB requests, and the nbd block driver does
> not take this into account.
> 
> Luckily, flush/FUA support is being worked out by upstream,
> and discard can also be added with the same framework (patches
> 1 to 6).
> 
> Asynchronous support is also very similar to what sheepdog is
> already doing (patches 7 to 12).
> 
> Paolo Bonzini (12):
>   nbd: support feature negotiation
>   nbd: sync API definitions with upstream
>   nbd: support NBD_SET_FLAGS ioctl
>   nbd: add support for NBD_CMD_FLUSH
>   nbd: add support for NBD_CMD_FLAG_FUA
>   nbd: support NBD_CMD_TRIM in the server
>   sheepdog: add coroutine_fn markers
>   add socket_set_block
>   sheepdog: move coroutine send/recv function to generic code
>   block: add bdrv_co_flush support
>   nbd: switch to asynchronous operation
>   nbd: split requests
> 
>  block.c          |   53 ++++++++++---
>  block/nbd.c      |  225 ++++++++++++++++++++++++++++++++++++++++++++--------
>  block/sheepdog.c |  235 +++++++-----------------------------------------------
>  block_int.h      |    1 +
>  cutils.c         |  108 +++++++++++++++++++++++++
>  nbd.c            |   80 +++++++++++++++++--
>  nbd.h            |   20 ++++-
>  oslib-posix.c    |    7 ++
>  oslib-win32.c    |    6 ++
>  qemu-common.h    |    3 +
>  qemu-coroutine.c |   71 ++++++++++++++++
>  qemu-coroutine.h |   26 ++++++
>  qemu-nbd.c       |   13 ++--
>  qemu_socket.h    |    1 +
>  14 files changed, 580 insertions(+), 269 deletions(-)

There is anonther patch enabling AIO for NBD on the list [1], by
Nicholas Thomas (CCed), that lacked review so far. Can you guys please
review each others approach and then converge on a solution? I guess
Paolo's patches 1-7 can be applied in any case, probably causing minor
conflicts, but for the rest we need to decide which one to pick.

Kevin

[1] http://www.mail-archive.com/qemu-devel@nongnu.org/msg74711.html