From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elder Subject: Re: [PATCH v3 5/5] rbd: fix error handling from rbd_snap_name() Date: Mon, 09 Sep 2013 08:49:07 -0500 Message-ID: <522DD1D3.2040805@linaro.org> References: <1378711022-20158-1-git-send-email-josh.durgin@inktank.com> <1378711022-20158-6-git-send-email-josh.durgin@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-oa0-f43.google.com ([209.85.219.43]:44159 "EHLO mail-oa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359Ab3IINtD (ORCPT ); Mon, 9 Sep 2013 09:49:03 -0400 Received: by mail-oa0-f43.google.com with SMTP id i10so6440681oag.2 for ; Mon, 09 Sep 2013 06:49:02 -0700 (PDT) In-Reply-To: <1378711022-20158-6-git-send-email-josh.durgin@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Josh Durgin Cc: ceph-devel@vger.kernel.org On 09/09/2013 02:17 AM, Josh Durgin wrote: > rbd_snap_name() calls rbd_dev_v{1,2}_snap_name() depending on the > format of the image. The format 1 version returns NULL on error, which > is handled by the caller. The format 2 version returns an ERR_PTR, > which the caller of rbd_snap_name() does not expect. > > Fortunately this is unlikely to occur in practice because > rbd_snap_id_by_name() is called before rbd_snap_name(). This would hit > similar errors to rbd_snap_name() (like the snapshot not existing) and > return early, so rbd_snap_name() would not hit an error unless the > snapshot was removed between the two calls or memory was exhausted. > > Use an ERR_PTR in rbd_dev_v1_snap_name() so that the specific error > can be propagated, and it is consistent with rbd_dev_v2_snap_name(). > Handle the ERR_PTR in the only rbd_snap_name() caller. Looks good. Reviewed-by: Alex Elder > Suggested-by: Alex Elder > Signed-off-by: Josh Durgin > --- > drivers/block/rbd.c | 10 ++++++---- > 1 files changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c > index 226fa04..16384b7 100644 > --- a/drivers/block/rbd.c > +++ b/drivers/block/rbd.c > @@ -927,12 +927,14 @@ static const char *rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, > u64 snap_id) > { > u32 which; > + const char *snap_name; > > which = rbd_dev_snap_index(rbd_dev, snap_id); > if (which == BAD_SNAP_INDEX) > - return NULL; > + return ERR_PTR(-ENOENT); > > - return _rbd_dev_v1_snap_name(rbd_dev, which); > + snap_name = _rbd_dev_v1_snap_name(rbd_dev, which); > + return snap_name ? snap_name : ERR_PTR(-ENOMEM); > } > > static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id) > @@ -4163,8 +4165,8 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev) > /* Look up the snapshot name, and make a copy */ > > snap_name = rbd_snap_name(rbd_dev, spec->snap_id); > - if (!snap_name) { > - ret = -ENOMEM; > + if (IS_ERR(snap_name)) { > + ret = PTR_ERR(snap_name); > goto out_err; > } > >