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 X-Spam-Level: X-Spam-Status: No, score=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A842C432BE for ; Tue, 24 Aug 2021 17:13:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D5A36142A for ; Tue, 24 Aug 2021 17:13:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235069AbhHXRNo (ORCPT ); Tue, 24 Aug 2021 13:13:44 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:48312 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235410AbhHXRLi (ORCPT ); Tue, 24 Aug 2021 13:11:38 -0400 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 6035721E7F; Tue, 24 Aug 2021 17:10:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1629825053; 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=Qf1sHMSuliqlUnVht35CsplQIRGW+naHlZ1RFNkw6d8=; b=IexOEpjqL7XK5jFcHzMNRf5W0n5iMErvu6SAG2jwNaQ8yeLe3KLyLXyZGlXMnoJd09I7sx Ry7H5os2j5pm2CNb5SM3iBGqVGgPkTtEF2gKT+Lxod6788tt3SfOGNxxJxkkoZ3DzoR5zY VIe64k6YWhHOHpIdquXZVi0NxwExKGI= 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 08E0313B45; Tue, 24 Aug 2021 17:10:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id oDF7MBsoJWGDNwAAMHmgww (envelope-from ); Tue, 24 Aug 2021 17:10:51 +0000 From: Marcos Paulo de Souza To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.com, nborisov@suse.com, Marcos Paulo de Souza Subject: [PATCH 1/7] fs: btrfs: Introduce btrfs_for_each_slot Date: Tue, 24 Aug 2021 14:06:52 -0300 Message-Id: <20210824170658.12567-2-mpdesouza@suse.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210824170658.12567-1-mpdesouza@suse.com> References: <20210824170658.12567-1-mpdesouza@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org There is a common pattern when search for a key in btrfs: * Call btrfs_search_slot * Endless loop * If the found slot is bigger than the current items in the leaf, check the next one * If still not found in the next leaf, return 1 * Do something with the code * Increment current slot, and continue This pattern can be improved by creating an iterator macro, similar to those for_each_X already existing in the linux kernel. Using this approach means to reduce significantly boilerplate code, along making it easier to newcomers to understand how to code works. Signed-off-by: Marcos Paulo de Souza --- fs/btrfs/ctree.c | 28 ++++++++++++++++++++++++++++ fs/btrfs/ctree.h | 25 +++++++++++++++++++++++++ fs/btrfs/xattr.c | 40 ++++++++++++---------------------------- 3 files changed, 65 insertions(+), 28 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 84627cbd5b5b..b1aa6e3987d0 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2122,6 +2122,34 @@ 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 start point to validate the slot. + * + * Return 0 if the item is valid, 1 if not found and < 0 if error. + */ +int btrfs_valid_slot(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]; + + if (slot >= btrfs_header_nritems(leaf)) { + ret = btrfs_next_leaf(root, path); + if (ret) + return ret; + continue; + } + 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 f07c82fafa04..1e3c4a7741ca 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2912,6 +2912,31 @@ 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_valid_slot(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 returned value from btrfs_search_slot and + * btrfs_valid_slot, whatever is executed later. + * + * The iter_ret is an output variable that will contain the result of the + * btrfs_search_slot if it returns an error, or the value returned from + * btrfs_valid_slot otherwise. The return value can be 0 if the something was + * found, 1 if there weren't bigger leaves, and <0 if 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_valid_slot(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) { diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c index 8a4514283a4b..f85febba1891 100644 --- a/fs/btrfs/xattr.c +++ b/fs/btrfs/xattr.c @@ -274,10 +274,12 @@ int btrfs_setxattr_trans(struct inode *inode, const char *name, ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) { struct btrfs_key key; + struct btrfs_key found_key; struct inode *inode = d_inode(dentry); struct btrfs_root *root = BTRFS_I(inode)->root; struct btrfs_path *path; int ret = 0; + int iter_ret = 0; size_t total_size = 0, size_left = size; /* @@ -295,44 +297,22 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) path->reada = READA_FORWARD; /* search for our xattrs */ - ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); - if (ret < 0) - goto err; - - while (1) { + btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { struct extent_buffer *leaf; int slot; struct btrfs_dir_item *di; - struct btrfs_key found_key; u32 item_size; u32 cur; leaf = path->nodes[0]; slot = path->slots[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 everything - */ - ret = btrfs_next_leaf(root, path); - if (ret < 0) - goto err; - else if (ret > 0) - break; - continue; - } - - btrfs_item_key_to_cpu(leaf, &found_key, slot); - /* check to make sure this item is what we want */ - if (found_key.objectid != key.objectid) - break; - if (found_key.type > BTRFS_XATTR_ITEM_KEY) + if (found_key.objectid != key.objectid || + found_key.type > BTRFS_XATTR_ITEM_KEY) break; if (found_key.type < BTRFS_XATTR_ITEM_KEY) - goto next_item; + continue; di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); item_size = btrfs_item_size_nr(leaf, slot); @@ -365,9 +345,13 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size) cur += this_len; di = (struct btrfs_dir_item *)((char *)di + this_len); } -next_item: - path->slots[0]++; } + + if (iter_ret < 0) { + ret = iter_ret; + goto err; + } + ret = total_size; err: -- 2.31.1