From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([209.51.188.92]:40527)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1h2JQu-0000Jb-NM
	for qemu-devel@nongnu.org; Fri, 08 Mar 2019 12:37:21 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <peter.maydell@linaro.org>) id 1h2JQt-0000E7-LJ
	for qemu-devel@nongnu.org; Fri, 08 Mar 2019 12:37:20 -0500
Received: from mail-oi1-x230.google.com ([2607:f8b0:4864:20::230]:38573)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
	(Exim 4.71) (envelope-from <peter.maydell@linaro.org>)
	id 1h2JQt-0000DM-BP
	for qemu-devel@nongnu.org; Fri, 08 Mar 2019 12:37:19 -0500
Received: by mail-oi1-x230.google.com with SMTP id q81so16472694oic.5
	for <qemu-devel@nongnu.org>; Fri, 08 Mar 2019 09:37:19 -0800 (PST)
MIME-Version: 1.0
References: <20190307095441.31921-1-kraxel@redhat.com>
	<20190307095441.31921-3-kraxel@redhat.com>
In-Reply-To: <20190307095441.31921-3-kraxel@redhat.com>
From: Peter Maydell <peter.maydell@linaro.org>
Date: Fri, 8 Mar 2019 17:37:06 +0000
Message-ID: <CAFEAcA8qsLyowga086b_ELvucVKWC+PSzykG3th81pnts1jiuQ@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Subject: Re: [Qemu-devel] [PULL 2/4] usb-mtp: fix some usb_mtp_write_data
 return paths
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>, Bandan Das <bsd@redhat.com>

On Thu, 7 Mar 2019 at 09:58, Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> From: Bandan Das <bsd@redhat.com>
>
> During a write, free up the "path" before getting more data.
> Also, while we at it, remove the confusing usage of d->fd for
> storing mkdir status
>
> Spotted by Coverity: CID 1398642
>
> Signed-off-by: Bandan Das <bsd@redhat.com>
> Message-id: 20190306210409.14842-3-bsd@redhat.com
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

Hi; Coverity found an issue with the code change here
(CID 1399415):

> index 4dde14fc7887..1f22284949df 100644
> --- a/hw/usb/dev-mtp.c
> +++ b/hw/usb/dev-mtp.c
> @@ -1605,7 +1605,7 @@ static int usb_mtp_update_object(MTPObject *parent, char *name)
>      return ret;
>  }
>
> -static void usb_mtp_write_data(MTPState *s)
> +static int usb_mtp_write_data(MTPState *s)

Here we change usb_mtp_write_data() to return an error code...

>  {
>      MTPData *d = s->data_out;
>      MTPObject *parent =

> @@ -1727,14 +1731,12 @@ static void usb_mtp_write_metadata(MTPState *s, uint64_t dlen)
>      s->write_pending = true;
>
>      if (s->dataset.format == FMT_ASSOCIATION) {
> -        usb_mtp_write_data(s);
> -        /* next_handle will be allocated to the newly created dir */
> -        if (d->fd == -1) {
> +        if (usb_mtp_write_data(s)) {
> +            /* next_handle will be allocated to the newly created dir */
>              usb_mtp_queue_result(s, RES_STORE_FULL, d->trans,
>                                   0, 0, 0, 0);
>              return;

...and we updated this callsite to check the error return value.

But the two places in usb_mtp_get_data() that call
usb_mtp_write_metadata() still don't check its return
value: don't they need to handle failure too?

thanks
-- PMM