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=-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=unavailable 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 0639FC11F7A for ; Mon, 12 Jul 2021 06:38:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DFB1A6117A for ; Mon, 12 Jul 2021 06:38:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237839AbhGLGlA (ORCPT ); Mon, 12 Jul 2021 02:41:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:55302 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236938AbhGLGcR (ORCPT ); Mon, 12 Jul 2021 02:32:17 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 303526052B; Mon, 12 Jul 2021 06:29:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626071368; bh=otGD2ARCskogymtuvkdl2jSshSk8OnBkPnOGZOfKfI0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hUSjHPY8B8GLvLq/3da87mb8Zr++ViEHdNkt1XAru/HDiZdptjUe5YKT4ajYVAERm hmja2/SBM7mHHH0kf2D9i1i6ZiMFuRKU5RLC1Jugo6BSU2E0RJabTYtO6jFmuRBtfN 3KObjLH/GUcEWjel7/kAnro3xstxe1TVjs451+G8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Sterba Subject: [PATCH 5.10 040/593] btrfs: compression: dont try to compress if we dont have enough pages Date: Mon, 12 Jul 2021 08:03:20 +0200 Message-Id: <20210712060847.591981655@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060843.180606720@linuxfoundation.org> References: <20210712060843.180606720@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 @@ -547,7 +547,7 @@ 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) {