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=-19.1 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 563F1C43214 for ; Wed, 1 Sep 2021 12:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3ED6061155 for ; Wed, 1 Sep 2021 12:36:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343593AbhIAMhh (ORCPT ); Wed, 1 Sep 2021 08:37:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:34434 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343566AbhIAMgC (ORCPT ); Wed, 1 Sep 2021 08:36:02 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F033661090; Wed, 1 Sep 2021 12:33:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1630499604; bh=LpVbVT5UPCEoz8bnrnxcToj1FZ2Pxvrd8UXF5JNzSio=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q4GxxdDCgSlw/sLGo5zwbS+nq4engvp9oDcrSFMPk4ByDKVAevm8lQTBP8MW/vy94 khXgu5DUpdakq9F5bAxD2+l7+KLfF1HL4b0HPlHqadOUmGp1+ybN7hBXddaQpCQjy2 nzGc6JqDLzLrQPgbbW5R/m0iz26XITsiMxF3Ravg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zygo Blaxell , Qu Wenruo , David Sterba Subject: [PATCH 5.10 015/103] Revert "btrfs: compression: dont try to compress if we dont have enough pages" Date: Wed, 1 Sep 2021 14:27:25 +0200 Message-Id: <20210901122301.043928981@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210901122300.503008474@linuxfoundation.org> References: <20210901122300.503008474@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: Qu Wenruo commit 4e9655763b82a91e4c341835bb504a2b1590f984 upstream. This reverts commit f2165627319ffd33a6217275e5690b1ab5c45763. [BUG] It's no longer possible to create compressed inline extent after commit f2165627319f ("btrfs: compression: don't try to compress if we don't have enough pages"). [CAUSE] For compression code, there are several possible reasons we have a range that needs to be compressed while it's no more than one page. - Compressed inline write The data is always smaller than one sector and the test lacks the condition to properly recognize a non-inline extent. - Compressed subpage write For the incoming subpage compressed write support, we require page alignment of the delalloc range. And for 64K page size, we can compress just one page into smaller sectors. For those reasons, the requirement for the data to be more than one page is not correct, and is already causing regression for compressed inline data writeback. The idea of skipping one page to avoid wasting CPU time could be revisited in the future. [FIX] Fix it by reverting the offending commit. Reported-by: Zygo Blaxell Link: https://lore.kernel.org/linux-btrfs/afa2742.c084f5d6.17b6b08dffc@tnonline.net Fixes: f2165627319f ("btrfs: compression: don't try to compress if we don't have enough pages") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Qu Wenruo Reviewed-by: David Sterba 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 (nr_pages > 1 && inode_need_compress(BTRFS_I(inode), start, end)) { + if (inode_need_compress(BTRFS_I(inode), start, end)) { WARN_ON(pages); pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!pages) {