From patchwork Mon Jul 12 06:02:09 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 475925 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 897EBC07E99 for ; Mon, 12 Jul 2021 06:55:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 740AB61369 for ; Mon, 12 Jul 2021 06:55:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239672AbhGLG6P (ORCPT ); Mon, 12 Jul 2021 02:58:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:59302 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238403AbhGLG5H (ORCPT ); Mon, 12 Jul 2021 02:57:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E2E4B61361; Mon, 12 Jul 2021 06:54:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626072859; bh=Vz/8nZG8zcT/Di9vwI6Q5i3RZv9Eig3ce4H3Fe2Gr2Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2NczqGdAvF5ldHovSiv1UKgD1gbUa+5AXYwGiH2O89SGyYU0cyjmXF7k/sifyRiOq 7pgWR4yBZ1Ilo+GJN7a3j8feRNs43wRencQ1qRuZqxIt9rzj4+8hMWVTWCIl8Qh30d 3U6GSkEtATF9YXuzJHelaRiH5loipQptYQcEZvnE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Sterba Subject: [PATCH 5.12 046/700] btrfs: compression: dont try to compress if we dont have enough pages Date: Mon, 12 Jul 2021 08:02:09 +0200 Message-Id: <20210712060931.196287208@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060924.797321836@linuxfoundation.org> References: <20210712060924.797321836@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Sterba commit f2165627319ffd33a6217275e5690b1ab5c45763 upstream. The early check if we should attempt compression does not take into account the number of input pages. It can happen that there's only one page, eg. a tail page after some ranges of the BTRFS_MAX_UNCOMPRESSED have been processed, or an isolated page that won't be converted to an inline extent. The single page would be compressed but a later check would drop it again because the result size must be at least one block shorter than the input. That can never work with just one page. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -598,7 +598,7 @@ again: * inode has not been flagged as nocompress. This flag can * change at any time if we discover bad compression ratios. */ - if (inode_need_compress(BTRFS_I(inode), start, end)) { + if (nr_pages > 1 && inode_need_compress(BTRFS_I(inode), start, end)) { WARN_ON(pages); pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!pages) {