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=-18.8 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=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 CEFF8C2B9F4 for ; Mon, 14 Jun 2021 14:26:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A017A61242 for ; Mon, 14 Jun 2021 14:26:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234548AbhFNO2Y (ORCPT ); Mon, 14 Jun 2021 10:28:24 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:37522 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232809AbhFNO2S (ORCPT ); Mon, 14 Jun 2021 10:28:18 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 2658E1FD33; Mon, 14 Jun 2021 14:26:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1623680775; 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; bh=Nxl8aEZNO2CkPcdtI84T+kALrOSV0hfyaDn3yG5WeSY=; b=e9YGcOrc9hFTzdD8G+AI+w0dusX4SgiGlSKJXvhoOrovnv/Sulsp8R7hmFP/0FuOEOow0r q44Wmh3QJkPhPpRI+V+Ktshf9cAnzfHotkRFeG/AS0Y+mLxsybKM0D0PKmI2fLCPDgI8az N0tsC5B7DoVrjewio6or2YMZQ6ZgEY8= Received: from ds.suse.cz (ds.suse.cz [10.100.12.205]) by relay2.suse.de (Postfix) with ESMTP id 1FCEAA3BF4; Mon, 14 Jun 2021 14:26:15 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 860D0DB228; Mon, 14 Jun 2021 16:23:28 +0200 (CEST) From: David Sterba To: linux-btrfs@vger.kernel.org Cc: David Sterba , stable@vger.kernel.org Subject: [PATCH] btrfs: compression: don't try to compress if we don't have enough pages Date: Mon, 14 Jun 2021 16:23:27 +0200 Message-Id: <20210614142327.30619-1-dsterba@suse.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 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 --- fs/btrfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index a2494c645681..e6eb20987351 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -629,7 +629,7 @@ static noinline int compress_file_range(struct async_chunk *async_chunk) * 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) { -- 2.31.1