From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6494C19F2A for ; Thu, 4 Aug 2022 15:52:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229596AbiHDPw3 (ORCPT ); Thu, 4 Aug 2022 11:52:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230482AbiHDPw2 (ORCPT ); Thu, 4 Aug 2022 11:52:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7DC757261 for ; Thu, 4 Aug 2022 08:52:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 90F07B824B3 for ; Thu, 4 Aug 2022 15:52:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE4D0C433D7; Thu, 4 Aug 2022 15:52:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659628344; bh=BIpKGG+3coT5lIJy9aTCw7szwAP7WT6BlVRlSCMPbNA=; h=Date:From:To:Subject:References:In-Reply-To:From; b=cQHxd4ELHrEN0BMLqXN0Ao4NaPQ+ZBLSjbFHcaJn6yf2EqXUfvq9iqwbc4SBHNtk0 tP9hi7afiJfiNkWx768SlUE3EPCjeKDKROqAhGJ878tmABlhHOPjH1JnTMlxvcbcAK Dq8g0LFKDF1CM5e+UC8FeBgk4UydKApvRSwi0hoJGy4s2j0Om+p9zCCPvhp0SUFqUI Fs3UdEWul0xM6tscy2XRzEAefQz4ZQesTm0ZMVX/BI77nBKpUdiUHK6GIENwyqYxVZ bcDN9pwNv5UkL6uIIBgTevL7PWeVJE18a8cmocoEbJVvB6wYN0sI0kzACr0KRgDWSy BhEvcmOd47DbA== Date: Thu, 4 Aug 2022 16:52:21 +0100 From: Filipe Manana To: dsterba@suse.cz, Nikolay Borisov , linux-btrfs@vger.kernel.org Subject: Re: [PATCH 1/3] btrfs: introduce btrfs_find_inode Message-ID: <20220804155221.GA1840473@falcondesktop> References: <20220721135006.3345302-1-nborisov@suse.com> <20220721135006.3345302-2-nborisov@suse.com> <20220804152823.GT13489@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220804152823.GT13489@twin.jikos.cz> Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Aug 04, 2022 at 05:28:24PM +0200, David Sterba wrote: > On Thu, Jul 21, 2022 at 04:50:04PM +0300, Nikolay Borisov wrote: > > This function holds common code for searching the root's inode rb tree. > > It will be used to reduce code duplication in future patches. > > > > Signed-off-by: Nikolay Borisov > > --- > > fs/btrfs/ctree.h | 1 + > > fs/btrfs/inode.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 45 insertions(+) > > > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > > index 0ae7f6530da1..fc0a0ab01761 100644 > > --- a/fs/btrfs/ctree.h > > +++ b/fs/btrfs/ctree.h > > @@ -3311,6 +3311,7 @@ int btrfs_set_inode_index(struct btrfs_inode *dir, u64 *index); > > int btrfs_unlink_inode(struct btrfs_trans_handle *trans, > > struct btrfs_inode *dir, struct btrfs_inode *inode, > > const char *name, int name_len); > > +struct rb_node *btrfs_find_inode(struct btrfs_root *root, const u64 objectid); > > int btrfs_add_link(struct btrfs_trans_handle *trans, > > struct btrfs_inode *parent_inode, struct btrfs_inode *inode, > > const char *name, int name_len, int add_backref, u64 index); > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > > index 5fc831a8eba1..c11169ba28b2 100644 > > --- a/fs/btrfs/inode.c > > +++ b/fs/btrfs/inode.c > > @@ -4587,6 +4587,50 @@ static noinline int may_destroy_subvol(struct btrfs_root *root) > > return ret; > > } > > > > +/** > > + * btrfs_find_inode - returns the rb_node pointing to the inode with an ino > > + * equal or larger than @objectid > > Please use the simplified format that we have in btrfs. > > > + * > > + * @root: root which is going to be searched for an inode > > + * @objectid: ino being searched for, if no exact match can be found the > > + * function returns the first largest inode > > + * > > + * Returns the rb_node pointing to the specified inode or returns NULL if no > > + * match is found. > > + * > > + */ > > +struct rb_node *btrfs_find_inode(struct btrfs_root *root, const u64 objectid) > > Const arguments for int types does not make sense. It makes sense to me, as much as declaring local variables as const, and I don't recall you ever complain about local const variables before (I do it often, and I'm not the only one). Once I read the const part, I can tell for sure that nowhere in the function the value of the argument is changed. It happens often that large functions use an int argument as if it was a local variable and change its value later on, which makes reading the code often a bit more time consuming and often leads to mistakest too. > The root can be made > const, compile tested, no complaints. > > > +{ > > + struct rb_node *node = root->inode_tree.rb_node; > > + struct rb_node *prev = NULL; > > + struct btrfs_inode *entry; > > + > > + lockdep_assert_held(&root->inode_lock); > > + > > + while (node) { > > + prev = node; > > + entry = rb_entry(node, struct btrfs_inode, rb_node); > > + > > + if (objectid < btrfs_ino(entry)) > > + node = node->rb_left; > > + else if (objectid > btrfs_ino(entry)) > > + node = node->rb_right; > > + else > > + break; > > + } > > + > > + if (!node) { > > + while (prev) { > > + entry = rb_entry(prev, struct btrfs_inode, rb_node); > > + if (objectid <= btrfs_ino(entry)) > > + return prev; > > + prev = rb_next(prev); > > + } > > + } > > + > > + return node; > > +} > > + > > /* Delete all dentries for inodes belonging to the root */ > > static void btrfs_prune_dentries(struct btrfs_root *root) > > { > > -- > > 2.25.1