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,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 5FEE0C11F66 for ; Tue, 13 Jul 2021 06:15:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 474F8611AB for ; Tue, 13 Jul 2021 06:15:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234118AbhGMGSl (ORCPT ); Tue, 13 Jul 2021 02:18:41 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:36794 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233007AbhGMGSk (ORCPT ); Tue, 13 Jul 2021 02:18:40 -0400 Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id BD189221D2 for ; Tue, 13 Jul 2021 06:15:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1626156950; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VR8XnNYlhdDP3tDYxsEuqMHh2Ggoxee8FcuSMgPQH88=; b=lRmtnsZV1i7awwsvrc2pAnrhbp8ll1pxAHfIVT1/Gvt2Xb/EI+RwJGrqPxSnHkp83LoBr0 1wk1CNQ7/LJsZR2F4JNyE5t7uw5ML7xMsp0LcXkANx8r8hjHCjGgjsaNdWuvJTZe6qE1RZ Y/lvnhuL3nxFvfpnA4kneh0qgMf0ZAg= Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id 06AD9139AC for ; Tue, 13 Jul 2021 06:15:49 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id uBm0LpUv7WB0XgAAGKfGzw (envelope-from ) for ; Tue, 13 Jul 2021 06:15:49 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH 25/27] btrfs: allow subpage to compress a range which only covers one page Date: Tue, 13 Jul 2021 14:15:14 +0800 Message-Id: <20210713061516.163318-26-wqu@suse.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210713061516.163318-1-wqu@suse.com> References: <20210713061516.163318-1-wqu@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org [BUG] With expertimental subpage compression write enabled, btrfs still refuse to compress a completely valid range: mkfs.btrfs -f -s 4k $dev mount $dev -o compress $mnt xfs_io -f -c "pwrite 0 64K" $mnt/file umount $mnt The result extent is uncompressed. [CAUSE] It turns out we have extra check on whether we should compress the range in compress_file_range(). The check looks like: if (nr_pages > 1 && inode_need_compress(BTRFS_I(inode), start, end)) { This means, we will only compress range which covers more than one page. This check no longer makes sense for subpage, as one page can contain several sectors. [FIX] Don't use @nr_pages, but directly compare @total_compressed against @blocksize to determine whether we need to do compression. Signed-off-by: Qu Wenruo --- fs/btrfs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 1432e268c13e..1cab1e99e46e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -630,7 +630,8 @@ 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 (nr_pages > 1 && inode_need_compress(BTRFS_I(inode), start, end)) { + if (total_compressed > blocksize && + inode_need_compress(BTRFS_I(inode), start, end)) { WARN_ON(pages); pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!pages) { -- 2.32.0