fix asynchronous ioctls

posix_aio_read expect aio requests to return the number of bytes
requests to be successfull, so we need to fake this up for ioctls.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/posix-aio-compat.c b/posix-aio-compat.c
index c7fdac70b4..e9fc9fa60a 100644
--- a/posix-aio-compat.c
+++ b/posix-aio-compat.c
@@ -90,7 +90,16 @@ static size_t handle_aiocb_ioctl(struct qemu_paiocb *aiocb)
 	ret = ioctl(aiocb->aio_fildes, aiocb->aio_ioctl_cmd, aiocb->aio_ioctl_buf);
 	if (ret == -1)
 		return -errno;
-	return ret;
+
+	/*
+	 * This looks weird, but the aio code only consideres a request
+	 * successfull if it has written the number full number of bytes.
+	 *
+	 * Now we overload aio_nbytes as aio_ioctl_cmd for the ioctl command,
+	 * so in fact we return the ioctl command here to make posix_aio_read()
+	 * happy..
+	 */
+	return aiocb->aio_nbytes;
 }
 
 #ifdef HAVE_PREADV