From patchwork Wed Jan 6 01:01:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 12000655 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=-18.8 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 94C80C433E0 for ; Wed, 6 Jan 2021 01:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B50F221E2 for ; Wed, 6 Jan 2021 01:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726917AbhAFBDj (ORCPT ); Tue, 5 Jan 2021 20:03:39 -0500 Received: from mx2.suse.de ([195.135.220.15]:45864 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726901AbhAFBDj (ORCPT ); Tue, 5 Jan 2021 20:03:39 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1609894937; 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=+7EQai5tbuQ+9vQMHjRvC72RHqNGw7lLMYXFsfh+x6s=; b=aeup/mxPGlUBTiKGp7psW1lx0bQKBteHfTV3mfsPyoaHSPjiohNd4s1lf3WFdJccVWao2j 30I0uH06PqHycHTEs6xBMSt9CbRVVzvqTEqp99ecoS96VhGgKrU2U4Gu/fMWeKma93d364 qJVBE1Uo/rAGSkhVuIic9Qw+DLHs3QQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 7E10CAF37; Wed, 6 Jan 2021 01:02:17 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: Johannes Thumshirn Subject: [PATCH v3 06/22] btrfs: extent_io: introduce a helper to grab an existing extent buffer from a page Date: Wed, 6 Jan 2021 09:01:45 +0800 Message-Id: <20210106010201.37864-7-wqu@suse.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210106010201.37864-1-wqu@suse.com> References: <20210106010201.37864-1-wqu@suse.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This patch will extract the code to grab an extent buffer from a page into a helper, grab_extent_buffer_from_page(). This reduces one indent level, and provides the work place for later expansion for subapge support. Reviewed-by: Johannes Thumshirn Signed-off-by: Qu Wenruo --- fs/btrfs/extent_io.c | 51 +++++++++++++++++++++++++++----------------- 1 file changed, 31 insertions(+), 20 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index a2a9c2148e91..d60f1837f8fb 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -5248,6 +5248,30 @@ struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info, } #endif +static struct extent_buffer *grab_extent_buffer(struct page *page) +{ + struct extent_buffer *exists; + + /* Page not yet attached to an extent buffer */ + if (!PagePrivate(page)) + return NULL; + + /* + * We could have already allocated an eb for this page + * and attached one so lets see if we can get a ref on + * the existing eb, and if we can we know it's good and + * we can just return that one, else we know we can just + * overwrite page->private. + */ + exists = (struct extent_buffer *)page->private; + if (atomic_inc_not_zero(&exists->refs)) + return exists; + + WARN_ON(PageDirty(page)); + detach_page_private(page); + return NULL; +} + struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start, u64 owner_root, int level) { @@ -5293,26 +5317,13 @@ struct extent_buffer *alloc_extent_buffer(struct btrfs_fs_info *fs_info, } spin_lock(&mapping->private_lock); - if (PagePrivate(p)) { - /* - * We could have already allocated an eb for this page - * and attached one so lets see if we can get a ref on - * the existing eb, and if we can we know it's good and - * we can just return that one, else we know we can just - * overwrite page->private. - */ - exists = (struct extent_buffer *)p->private; - if (atomic_inc_not_zero(&exists->refs)) { - spin_unlock(&mapping->private_lock); - unlock_page(p); - put_page(p); - mark_extent_buffer_accessed(exists, p); - goto free_eb; - } - exists = NULL; - - WARN_ON(PageDirty(p)); - detach_page_private(p); + exists = grab_extent_buffer(p); + if (exists) { + spin_unlock(&mapping->private_lock); + unlock_page(p); + put_page(p); + mark_extent_buffer_accessed(exists, p); + goto free_eb; } attach_extent_buffer_page(eb, p); spin_unlock(&mapping->private_lock);