block/vhdx.c: Mark parent_vhdx_guid variable as unused

The parent_vhdx_guid variable is defined but never used, which provokes
complaints from newer versions of clang. Since the variable definition
is here acting as documentation of the image format, mark it with the
'unused' attribute to keep the compiler happy rather than simply
deleting it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
ide/atapi: Mark non-data commands as complete

When the command completion code in IDE and AHCI
was unified to put all command completion inside
of a callback, "cmd_done," we neglected to
ensure that all AHCI/ATAPI command paths would
eventually register as finished. for the PCI
interface to IDE this is not a problem because
cmd_done is a nop, but the AHCI implementation
needs to send a D2H_REG_FIS and interrupt back
to the guest to inform of completion.

This patch adds calls to ide_stop_transfer,
which calls ide_cmd_done, inside of
ide_atapi_cmd_ok and ide_atapi_cmd_error.

This fixes regressions observed by trying to boot QEMU
with a Fedora 20 live CD under Q35/AHCI, which uses
ATAPI command 0x00, which is a status check that may
cause a hang because we never complete, and ATAPI
command 0x56, which is unsupported by our current
implementation and results in an error that we never
report back to the guest.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
aio-win32: fix uninitialized use of have_select_revents

Always initialize it with the return value of aio_prepare.

Reported-by: TeLeMan <geleman@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
ide/ahci: Check for -ECANCELED in aio callbacks

Before, bdrv_aio_cancel will either complete the request (like normal)
and call CB with an actual return code, or skip calling the request (for
example when the IO req is not submitted by thread pool yet).

We will change bdrv_aio_cancel to do it differently: always call CB
before return, with either [1] a normal req completion ret code, or [2]
ret == -ECANCELED. So the callers' callback must accept both cases. The
existing logic works with case [1], but not [2].

The simplest transition of callback code is do nothing in case [2], just
as if the CB is not called by the bdrv_aio_cancel() call.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Add refcnt in BlockDriverAIOCB

This will be useful in synchronous cancel emulation with
bdrv_aio_cancel_async.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Add bdrv_aio_cancel_async

This is the async version of bdrv_aio_cancel, which doesn't block the
caller. It guarantees that the cb is called either before returning or
some time later.

bdrv_aio_cancel can base on bdrv_aio_cancel_async, later we can convert
all .io_cancel implementations to .io_cancel_async, and the aio_poll is
the common logic. In the end, .io_cancel can be dropped.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Drop bdrv_em_co_aiocb_info.cancel

Also drop the now unused ->done pointer.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
block: Drop bdrv_em_aiocb_info.cancel

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
thread-pool: Convert thread_pool_aiocb_info.cancel to cancel_async

The .cancel_async shares the same the first half with .cancel: try to
steal the request if not submitted yet. In this case set the elem to
THREAD_DONE status and ret to -ECANCELED, which means
thread_pool_completion_bh will call the cb with -ECANCELED.

If the request is already submitted, do nothing, as we know the normal
completion will happen in the future.

Testing code update:

Before, done_cb is only called if the request is already submitted by
thread pool. Now done_cb is always called, even before it is submitted,
because we emulate bdrv_aio_cancel with bdrv_aio_cancel_async. So also
update the test criteria accordingly.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
linux-aio: Convert laio_aiocb_info.cancel to .cancel_async

Just call io_cancel (2), if it fails, it means the request is not
canceled, so the event loop will eventually call
qemu_laio_process_completion.

In qemu_laio_process_completion, change to call the cb unconditionally.
It is required by bdrv_aio_cancel_async.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
dma: Convert dma_aiocb_info.cancel to .cancel_async

Just forward the request to bdrv_aio_cancel_async.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
iscsi: Convert iscsi_aiocb_info.cancel to .cancel_async

Also drop the unused field "canceled".

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
archipelago: Drop archipelago_aiocb_info.cancel

The cancelled flag is no longer useful. Later the request will complete
as before, and cb will be called.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
blkdebug: Drop blkdebug_aiocb_info.cancel

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
blkverify: Drop blkverify_aiocb_info.cancel

Also the finished pointer is not used any more.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
curl: Drop curl_aiocb_info.cancel

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
qed: Drop qed_aiocb_info.cancel

Also drop the now unused ->finished field.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
quorum: fix quorum_aio_cancel()

For a fifo read pattern, we only have one running aio (possible other cases that
has less number than num_children in the future), so we need to check if
.acb is NULL against bdrv_aio_cancel() to avoid segfault.

Cc: Eric Blake <eblake@redhat.com>
Cc: Benoit Canet <benoit@irqsave.net>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liu Yuan <namei.unix@gmail.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
quorum: Convert quorum_aiocb_info.cancel to .cancel_async

Before, we cancel all the child requests with bdrv_aio_cancel, then free
the acb..

Now we just kick off asynchronous cancellation of child requests and
return, we know quorum_aio_cb will be called later, so in the end
quorum_aio_finalize will take care of calling the caller's cb.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
rbd: Drop rbd_aiocb_info.cancel

And also drop the now unused "cancelled" field.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>