From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: [PATCH 4/4] rbd: use snaps list in rbd_snap_by_name() Date: Mon, 10 Sep 2012 15:32:09 -0700 Message-ID: <504E6A69.8070109@inktank.com> References: <504A090F.7000706@inktank.com> <504A09BA.5030203@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:38909 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756329Ab2IJWcV (ORCPT ); Mon, 10 Sep 2012 18:32:21 -0400 Received: by pbbrr13 with SMTP id rr13so3136644pbb.19 for ; Mon, 10 Sep 2012 15:32:21 -0700 (PDT) In-Reply-To: <504A09BA.5030203@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alex Elder Cc: ceph-devel@vger.kernel.org On 09/07/2012 07:50 AM, Alex Elder wrote: > An rbd_dev structure maintains a list of current snapshots that have > already been fully initialized. The entries on the list have type > struct rbd_snap, and each entry contains a copy of information > that's found in the rbd_dev's snapshot context and header. > > The only caller of snap_by_name() is rbd_header_set_snap(). In that > call site any positive return value (the index in the snapshot > array) is ignored. > > rbd_header_set_snap() also has only one caller--rbd_add()--and that > call is made after a call to rbd_dev_snap_devs_update(). Because > the rbd_snap structures are initialized in that function, the > current snapshot list can be used instead of the snapshot context to > look up a snapshot's information by name. > > Change snap_by_name() so it uses the snapshot list rather than the > rbd_dev's snapshot context in looking up snapshot information. > Return 0 if it's found rather than the snapshot id. To do this, > change rbd_snap_by_name() to take an rbd_dev rather than > rbd_image_header structure pointer as its first argument. This argument change was an earlier commit now. > No caller ever passes a null pointer to snap_by_name() for the > snapshot id or the size, so just assign using those pointers > unconditionally. No caller passes id or size now either. With the commit message fixed: Reviewed-by: Josh Durgin > Signed-off-by: Alex Elder > --- > drivers/block/rbd.c | 19 +++++++------------ > 1 file changed, 7 insertions(+), 12 deletions(-) > > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c > index e922989..4dff92f 100644 > --- a/drivers/block/rbd.c > +++ b/drivers/block/rbd.c > @@ -623,23 +623,18 @@ out_err: > > static int snap_by_name(struct rbd_device *rbd_dev, const char *snap_name) > { > - int i; > - struct rbd_image_header *header = &rbd_dev->header; > - char *p = header->snap_names; > - > - rbd_assert(header->snapc != NULL); > - for (i = 0; i < header->snapc->num_snaps; i++) { > - if (!strcmp(snap_name, p)) { > > - /* Found it. Pass back its id and/or size */ > + struct rbd_snap *snap; > > - rbd_dev->mapping.snap_id = header->snapc->snaps[i]; > - rbd_dev->mapping.size = header->snap_sizes[i]; > + list_for_each_entry(snap, &rbd_dev->snaps, node) { > + if (!strcmp(snap_name, snap->name)) { > + rbd_dev->mapping.snap_id = snap->id; > + rbd_dev->mapping.size = snap->size; > > - return i; > + return 0; > } > - p += strlen(p) + 1; /* Skip ahead to the next name */ > } > + > return -ENOENT; > } >