From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36257) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xyp66-0004FG-T6 for qemu-devel@nongnu.org; Wed, 10 Dec 2014 16:47:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xyp5z-0002B3-CD for qemu-devel@nongnu.org; Wed, 10 Dec 2014 16:47:02 -0500 Received: from mail.hq.newdream.net ([66.33.206.127]:49567) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xyp5z-0002Au-7B for qemu-devel@nongnu.org; Wed, 10 Dec 2014 16:46:55 -0500 Message-ID: <5488BF9C.7080402@inktank.com> Date: Wed, 10 Dec 2014 13:48:12 -0800 From: Josh Durgin MIME-Version: 1.0 References: <1418226457-22239-1-git-send-email-junmuzi@gmail.com> In-Reply-To: <1418226457-22239-1-git-send-email-junmuzi@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] rbd: print a clear error message when write beyond EOF List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jun Li , qemu-devel@nongnu.org Cc: kwolf@redhat.com, juli@redhat.com, famz@redhat.com, stefanha@redhat.com On 12/10/2014 07:47 AM, Jun Li wrote: > Currently, as rbd driver do not support dynamic growth when write beyond EOF, > so just print a clear error message. > > Signed-off-by: Jun Li > --- > block/rbd.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/block/rbd.c b/block/rbd.c > index 5b5a64a..65b01f0 100644 > --- a/block/rbd.c > +++ b/block/rbd.c > @@ -693,6 +693,20 @@ static BlockAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs, > BlockCompletionFunc *cb, > void *opaque) > { > + BDRVRBDState *s = bs->opaque; > + uint64_t total_size; > + int64_t off, size; > + > + off = sector_num * BDRV_SECTOR_SIZE; > + size = nb_sectors * BDRV_SECTOR_SIZE; > + rbd_get_size(s->image, &total_size); > + > + if (off + size > total_size) { > + fprintf(stdout, "Image formats that grow on demand" > + "are not supported on rbd.\n"); > + return NULL; > + } > + > return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque, > RBD_AIO_WRITE); > } > This is one of the checks librbd does itself, so we could just look for an EINVAL from rbd_aio_{read,write,discard} in rbd_start_aio() to avoid duplicating the check. An out of bounds i/o is the only way EINVAL can be returned from these functions in librbd. Josh