From patchwork Wed Mar 2 16:48:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Niebler X-Patchwork-Id: 12766318 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 F2664C433EF for ; Wed, 2 Mar 2022 16:50:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243527AbiCBQvI (ORCPT ); Wed, 2 Mar 2022 11:51:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243530AbiCBQvH (ORCPT ); Wed, 2 Mar 2022 11:51:07 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB20CCA739 for ; Wed, 2 Mar 2022 08:50:23 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 7B939218B0; Wed, 2 Mar 2022 16:50:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1646239822; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=crDsiwbz6UoOwR51+Te8QxRNZkcRQe9R/X4QVK6hghE=; b=epEi/pSJF9DoUyu9P50QUaY9EgHWeUPOsDe7rRBeF2R/KAdk0hYsHwjiv4Rze8qhKxADGv mzaxM8kCWxYWJaVw7H+s7eQ3rOGIAjyqibzMVSwTPktZMaxhITsqxHomuc2KGaxMRS6Fzw G1es4KPEQ1nG/GpihYtFJUy/vrbhpGs= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 4B78C13A93; Wed, 2 Mar 2022 16:50:22 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id yHBmEE6gH2LdOwAAMHmgww (envelope-from ); Wed, 02 Mar 2022 16:50:22 +0000 From: Gabriel Niebler To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.com, Gabriel Niebler , Marcos Paulo de Souza Subject: [PATCH v3 01/14] btrfs: Introduce btrfs_for_each_slot iterator macro Date: Wed, 2 Mar 2022 17:48:16 +0100 Message-Id: <20220302164829.17524-2-gniebler@suse.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220302164829.17524-1-gniebler@suse.com> References: <20220302164829.17524-1-gniebler@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org There is a common pattern when searching for a key in btrfs: * Call btrfs_search_slot to find the slot for the key * Enter an endless loop: * If the found slot is larger than the no. of items in the current leaf, check the next leaf * If it's still not found in the next leaf, terminate the loop * Otherwise do something with the found key * Increment the current slot and continue To reduce code duplication, we can replace this code pattern with an iterator macro, similar to the existing for_each_X macros found elsewhere in the kernel. This also makes the code easier to understand for newcomers by putting a name to the encapsulated functionality. Signed-off-by: Marcos Paulo de Souza Signed-off-by: Gabriel Niebler --- fs/btrfs/ctree.c | 33 +++++++++++++++++++++++++++++++++ fs/btrfs/ctree.h | 24 ++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index a7db3f6f1b7b..d735bd472616 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2277,6 +2277,39 @@ int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, return ret; } +/* Search for a valid slot for the given path. + * + * @root: The root node of the tree. + * @key: Will contain a valid item if found. + * @path: The starting point to validate the slot. + * + * Return 0 if the item is valid, 1 if not found and < 0 if error. + */ +int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, + struct btrfs_path *path) +{ + while (1) { + int ret; + const int slot = path->slots[0]; + const struct extent_buffer *leaf = path->nodes[0]; + /* this is where we start walking through the path */ + if (slot >= btrfs_header_nritems(leaf)) { + /* + * if we've reached the last slot in this leaf we need + * to go to the next leaf and reset the path + */ + ret = btrfs_next_leaf(root, path); + if (ret) + return ret; + continue; + } + /* store the found, valid item in key */ + btrfs_item_key_to_cpu(leaf, key, slot); + break; + } + return 0; +} + /* * adjust the pointers going up the tree, starting at level * making sure the right key of each node is points to 'key'. diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 947f04789389..98091334b749 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2976,6 +2976,30 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, struct btrfs_path *path); +int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, + struct btrfs_path *path); + +/* Search in @root for a given @key, and store the slot found in @found_key. + * + * @root: The root node of the tree. + * @key: The key we are looking for. + * @found_key: Will hold the found item. + * @path: Holds the current slot/leaf. + * @iter_ret: Contains the value returned from btrfs_search_slot or + * btrfs_get_next_valid_item, whichever was executed last. + * + * The iter_ret is an output variable that will contain the return value of + * btrfs_search_slot, if it encountered an error, or the value returned from + * btrfs_get_next_valid_item, otherwise. That return value can be 0, if a valid + * slot was found, 1 if there were no more leaves, and <0 if there was an error. + */ +#define btrfs_for_each_slot(root, key, found_key, path, iter_ret) \ + for (iter_ret = btrfs_search_slot(NULL, root, key, path, 0, 0); \ + iter_ret >= 0 && \ + (iter_ret = btrfs_get_next_valid_item(root, found_key, path)) == 0; \ + path->slots[0]++ \ + ) + static inline int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *p, u64 time_seq) {