From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bk0-f42.google.com ([209.85.214.42]:63835 "EHLO mail-bk0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756593Ab3GDPzW (ORCPT ); Thu, 4 Jul 2013 11:55:22 -0400 Received: by mail-bk0-f42.google.com with SMTP id jk13so727498bkc.15 for ; Thu, 04 Jul 2013 08:55:21 -0700 (PDT) MIME-Version: 1.0 Reply-To: fdmanana@gmail.com In-Reply-To: <1372952919-21010-1-git-send-email-fdmanana@gmail.com> References: <1372869173-15043-1-git-send-email-fdmanana@gmail.com> <1372952919-21010-1-git-send-email-fdmanana@gmail.com> Date: Thu, 4 Jul 2013 16:55:21 +0100 Message-ID: Subject: Re: [PATCH] Btrfs-progs: fix optimization in btrfs_lookup_extent_info From: Filipe David Manana To: "linux-btrfs@vger.kernel.org" Cc: Filipe David Borba Manana , jbacik@fusionio.com Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Jul 4, 2013 at 4:48 PM, Filipe David Borba Manana wrote: > If we did a tree search with the goal to find a metadata item > but the search failed with return value 1, we attempt to see > if in the same leaf there's a corresponding extent item, and if > there's one, just use it instead of doing another tree search > for this extent item. The check in the leaf was wrong because > it was seeking for a metadata item instead of an extent item. > > This optimization was also being triggered incorrectly, as it > was evaluating path->slots which always evaluates to true. The > goal was to see if the leaf level slot was greater than zero > (i.e. not the first item in the leaf). > > Signed-off-by: Filipe David Borba Manana > --- > extent-tree.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/extent-tree.c b/extent-tree.c > index b0cfe0a..22e6247 100644 > --- a/extent-tree.c > +++ b/extent-tree.c > @@ -1515,12 +1515,13 @@ again: > * to make sure. > */ > if (ret > 0 && metadata) { > - if (path->slots) { > + if (path->slots[0]) { > path->slots[0]--; > btrfs_item_key_to_cpu(path->nodes[0], &key, > path->slots[0]); > if (key.objectid == bytenr && > - key.type == BTRFS_METADATA_ITEM_KEY) > + key.type == BTRFS_EXTENT_ITEM_KEY && > + key.offset == root->leafsize) > ret = 0; > } > > -- > 1.7.9.5 > Josef, since git suggests you are the author of this code piece, can you please review this and comment? Thanks. -- Filipe David Manana, "Reasonable men adapt themselves to the world. Unreasonable men adapt the world to themselves. That's why all progress depends on unreasonable men."