From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dkim2.fusionio.com ([66.114.96.54]:34453 "EHLO dkim2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756742Ab3GEU3V (ORCPT ); Fri, 5 Jul 2013 16:29:21 -0400 Received: from mx2.fusionio.com (unknown [10.101.1.160]) by dkim2.fusionio.com (Postfix) with ESMTP id 623D39A0695 for ; Fri, 5 Jul 2013 14:29:21 -0600 (MDT) Date: Fri, 5 Jul 2013 16:29:18 -0400 From: Josef Bacik To: Filipe David Borba Manana CC: Subject: Re: [PATCH v2] Btrfs-progs: fix optimization in btrfs_lookup_extent_info Message-ID: <20130705202918.GF2260@localhost.localdomain> References: <1372952919-21010-1-git-send-email-fdmanana@gmail.com> <1372955049-5051-1-git-send-email-fdmanana@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <1372955049-5051-1-git-send-email-fdmanana@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Jul 04, 2013 at 05:24:09PM +0100, 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). > > V2: If previous leaf item is for a different object, ensure the > search key has the target object id. > > Signed-off-by: Filipe David Borba Manana > --- > extent-tree.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/extent-tree.c b/extent-tree.c > index b0cfe0a..875dea9 100644 > --- a/extent-tree.c > +++ b/extent-tree.c > @@ -1515,17 +1515,19 @@ 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; > } > > if (ret) { > btrfs_release_path(root, path); > + key.objectid = bytenr; > key.type = BTRFS_EXTENT_ITEM_KEY; > key.offset = root->leafsize; > metadata = 0; Reviewed-by: Josef Bacik Thanks, Josef