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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 03096C3A5A9 for ; Tue, 5 May 2020 02:08:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CEF9120705 for ; Tue, 5 May 2020 02:08:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588644526; bh=WA4NF4Zrsn/AZscHkiK0AuxGMzZiCnAsbzhY8KUi4w0=; h=Subject:To:References:From:Date:In-Reply-To:List-ID:From; b=fFbp644ZHKBsy7Rk7kCxjk5wTGx17Trb/wVbdwkzCYZ+SexH+GLXR2KGrYfmauESU dwBmhKTtlkL0X8uDxG+Ty5Fl2R7LaQBOdDvZW1CuUxRHx4AAU+yMRE3hXwmvekHcxE k21fIjnU9ZlyTJ6g5k+4fv+zSo0vmfnM1fbsLmYQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728083AbgEECIq (ORCPT ); Mon, 4 May 2020 22:08:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:33954 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726449AbgEECIp (ORCPT ); Mon, 4 May 2020 22:08:45 -0400 Received: from [192.168.0.107] (unknown [58.213.210.203]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 96F2F206D7; Tue, 5 May 2020 02:08:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588644525; bh=WA4NF4Zrsn/AZscHkiK0AuxGMzZiCnAsbzhY8KUi4w0=; h=Subject:To:References:From:Date:In-Reply-To:From; b=fMN8n8tRQXf1Xn4ZeO8JjyvlKub1XKr/IMBo7ozbkZDKaAMKH29LkrAWe0quuLyIM Orp6jaTKVFgbxlOCLm+liNy9gek39BAcEW2E82h3Cjj7RJYcH0NiWAw8jLZFDuGtQK qtMDBUCKIlx0o3D2eh15JtbooNKPgRjm4TWNW7I0= Subject: Re: [f2fs-dev] [PATCH] f2fs: change maximum zstd compression buffer size To: Jaegeuk Kim , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com References: <20200504143039.155644-1-jaegeuk@kernel.org> <7177aab9-630e-e077-7005-0023c93134b3@kernel.org> From: Chao Yu Message-ID: <5dadaf04-ef9e-f6a8-c132-8fa072e8e6fe@kernel.org> Date: Tue, 5 May 2020 10:08:37 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <7177aab9-630e-e077-7005-0023c93134b3@kernel.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-5-5 9:52, Chao Yu wrote: > On 2020-5-4 22:30, Jaegeuk Kim wrote: >> From: Daeho Jeong >> >> Current zstd compression buffer size is one page and header size less >> than cluster size. By this, zstd compression always succeeds even if >> the real compression data is failed to fit into the buffer size, and >> eventually reading the cluster returns I/O error with the corrupted >> compression data. > > What's the root cause of this issue? I didn't get it. > >> >> Signed-off-by: Daeho Jeong >> --- >> fs/f2fs/compress.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c >> index 4c7eaeee52336..a9fa8049b295f 100644 >> --- a/fs/f2fs/compress.c >> +++ b/fs/f2fs/compress.c >> @@ -313,7 +313,7 @@ static int zstd_init_compress_ctx(struct compress_ctx *cc) >> cc->private = workspace; >> cc->private2 = stream; >> >> - cc->clen = cc->rlen - PAGE_SIZE - COMPRESS_HEADER_SIZE; >> + cc->clen = ZSTD_compressBound(PAGE_SIZE << cc->log_cluster_size); Max size of intermediate buffer has been set as below? - zstd_init_compress_ctx - params = ZSTD_getParams(F2FS_ZSTD_DEFAULT_CLEVEL, cc->rlen, 0) - ZSTD_CStreamWorkspaceBound(params.cParams) - outBuffSize = ZSTD_compressBound(blockSize) + 1; - workspace_size = ... + outBuffSize + ... - workspace = f2fs_kvmalloc(workspace_size) > > In my machine, the value is 66572 which is much larger than size of dst buffer, > so, in where we can tell the real size of dst buffer to zstd compressor? > Otherwise, if compressed data size is larger than dst buffer size, when we flush > compressed data into dst buffer, we may suffer overflow. > >> return 0; >> } >> >> @@ -330,7 +330,7 @@ static int zstd_compress_pages(struct compress_ctx *cc) >> ZSTD_inBuffer inbuf; >> ZSTD_outBuffer outbuf; >> int src_size = cc->rlen; >> - int dst_size = src_size - PAGE_SIZE - COMPRESS_HEADER_SIZE; >> + int dst_size = cc->clen; >> int ret; >> >> inbuf.pos = 0; >> > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel