From patchwork Wed Apr 2 14:54:09 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 14036120 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CDCB823C8AD for ; Wed, 2 Apr 2025 14:54:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743605658; cv=none; b=KWybp6+BiKfP/KGh+cikLH7v1b/x3HpKT+Fop1o3lk7vhuJeGLZVf+/FKYEn28vh6BT6OyiqE4mZtyAb1S57chTbRgnemFvGDy44VHcg/ATO90MIXlQD0YZK34jJLCDbcSBASA+XueaSvltcSA16MWPstE965Y51ZeY8N9wvjJU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743605658; c=relaxed/simple; bh=D2uFBeAwqiEl/ocwtBlcwQeYyKQALWHpO51KWBko2mg=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=LrfecaWaq616lg1pS0yqEvnkpTui8hSeeQ9iZ4Z7+uE7ksx1gYxhjVkjdItqcUPCI9/EpYg3Lhh5OO7bSht+mH/7c4oAfFQGDeSwMcFdRzAGy0kyOZHav/acIm1WdUe4Xb8Kx5b6jhMNVSUd4aOYdbSAAnQ/YDiHFd97QrE6GB0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HFgNBzoC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HFgNBzoC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4787C4CEDD for ; Wed, 2 Apr 2025 14:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743605657; bh=D2uFBeAwqiEl/ocwtBlcwQeYyKQALWHpO51KWBko2mg=; h=From:To:Subject:Date:In-Reply-To:References:From; b=HFgNBzoCrfPN6Ney3GuplMzeZNcfG+SqwJux/AKhN1yNDe+T60pzeMmdW86js2RhS 2BTxxuFLQ+NGH748E9bGElS7qHNa5TYIgh03CRyhJy246mq+9R2wh2muhgrnVSBH7U EHiuoF1nynf55/SACjz7ENef1DTp3qU3ZxzaWVlUCv0jENoTAKGnFvog6a+UM4oN9K krC2Fc0zxDRK9pLcFw8YPwNXRTLJVU2Y0wt6SvzVPUu3O7MCjUBpZvKATSCNzEZMfJ 0pa+dznUUqmRc7IONlWCYI0g29bxaVB3JiQ9L7cn5ukeaFZmN5GAj7RnXbZzDlwFlw 53TZ2JsV9IXwA== From: fdmanana@kernel.org To: linux-btrfs@vger.kernel.org Subject: [PATCH 1/4] btrfs: fix documentation for tree_search_for_insert() Date: Wed, 2 Apr 2025 15:54:09 +0100 Message-Id: <37c8d8c041a01c8aa59673ffbd26bb0829f89ac8.1743604119.git.fdmanana@suse.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Filipe Manana There are several things wrong with the documentation: 1) At the top it's only mentioned that we search for an entry containing the given offset, but when such entry does not exists we search for the first entry that starts and ends after that offset; 2) It mentions that @node_ret and @parent_ret aren't changed if the returned entry contains the given offset - that is true only if the returned entry starts exactly at @offset, otherwise those arguments are changed; 3) It mentions that if no entry containing offset is found then we return the first entry ending before the offset - that is not true, we return the first entry that starts and ends after that offset; 4) It also mentions that NULL is never returned. This is false as in case there's no entry containing offset or any entry that starts and ends after offset, NULL is returned. So fix the documentation. Signed-off-by: Filipe Manana --- fs/btrfs/extent-io-tree.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c index 3c138e6c2397..355c24449776 100644 --- a/fs/btrfs/extent-io-tree.c +++ b/fs/btrfs/extent-io-tree.c @@ -233,21 +233,23 @@ static inline struct extent_state *prev_state(struct extent_state *state) } /* - * Search @tree for an entry that contains @offset. Such entry would have - * entry->start <= offset && entry->end >= offset. + * Search @tree for an entry that contains @offset or if none exists for the + * first entry that starts and ends after that offset. * * @tree: the tree to search - * @offset: offset that should fall within an entry in @tree + * @offset: search offset * @node_ret: pointer where new node should be anchored (used when inserting an * entry in the tree) * @parent_ret: points to entry which would have been the parent of the entry, * containing @offset * - * Return a pointer to the entry that contains @offset byte address and don't change - * @node_ret and @parent_ret. + * Return a pointer to the entry that contains @offset byte address. * - * If no such entry exists, return pointer to entry that ends before @offset - * and fill parameters @node_ret and @parent_ret, ie. does not return NULL. + * If no such entry exists, return the first entry that starts and ends after + * @offset if one exists, otherwise NULL. + * + * If the returned entry starts at @offset, then @node_ret and @parent_ret + * aren't changed. */ static inline struct extent_state *tree_search_for_insert(struct extent_io_tree *tree, u64 offset, @@ -276,7 +278,11 @@ static inline struct extent_state *tree_search_for_insert(struct extent_io_tree if (parent_ret) *parent_ret = prev; - /* Search neighbors until we find the first one past the end */ + /* + * Return either the current entry if it contains offset (it ends after + * or at offset) or the first entry that starts and ends after offset if + * one exists, or NULL. + */ while (entry && offset > entry->end) entry = next_state(entry);