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=-16.2 required=3.0 tests=BAYES_00,BODY_ENHANCEMENT2, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 50ADDC43463 for ; Fri, 18 Sep 2020 01:47:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09D9A20872 for ; Fri, 18 Sep 2020 01:47:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726250AbgIRBro (ORCPT ); Thu, 17 Sep 2020 21:47:44 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:55806 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726221AbgIRBri (ORCPT ); Thu, 17 Sep 2020 21:47:38 -0400 Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 708EE202C310BC5EB2F7; Fri, 18 Sep 2020 09:47:36 +0800 (CST) Received: from [10.136.114.67] (10.136.114.67) by smtp.huawei.com (10.3.19.210) with Microsoft SMTP Server (TLS) id 14.3.487.0; Fri, 18 Sep 2020 09:47:32 +0800 Subject: Re: [PATCH 6/9] f2fs: zstd: Switch to the zstd-1.4.6 API To: Nick Terrell CC: Nick Terrell , "linux-f2fs-devel@lists.sourceforge.net" , "linux-kernel@vger.kernel.org" , Kernel Team , Chris Mason , Petr Malat , Johannes Weiner , Niket Agarwal , Yann Collet References: <20200916034307.2092020-1-nickrterrell@gmail.com> <20200916034307.2092020-9-nickrterrell@gmail.com> <28bf92f1-1246-a840-6195-0e230e517e6d@huawei.com> <9589E483-A94B-4AF6-8C03-B0763715B40A@fb.com> From: Chao Yu Message-ID: Date: Fri, 18 Sep 2020 09:47:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <9589E483-A94B-4AF6-8C03-B0763715B40A@fb.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.136.114.67] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/9/18 3:34, Nick Terrell wrote: > > >> On Sep 17, 2020, at 11:00 AM, Nick Terrell wrote: >> >> >> >>> On Sep 16, 2020, at 11:31 PM, Chao Yu wrote: >>> >>> Hi Nick, >>> >>> On 2020/9/17 2:39, Nick Terrell wrote: >>>>> On Sep 15, 2020, at 11:31 PM, Chao Yu wrote: >>>>> >>>>> Hi Nick, >>>>> >>>>> remove not related mailing list. >>>>> >>>>> On 2020/9/16 11:43, Nick Terrell wrote: >>>>>> From: Nick Terrell >>>>>> Move away from the compatibility wrapper to the zstd-1.4.6 API. This >>>>>> code is more efficient because it uses the single-pass API instead of >>>>>> the streaming API. The streaming API is not necessary because the whole >>>>>> input and output buffers are available. This saves memory because we >>>>>> don't need to allocate a buffer for the window. It is also more >>>>>> efficient because it saves unnecessary memcpy calls. >>>>>> I've had problems testing this code because I see data truncation before >>>>>> and after this patchset. Help testing this patch would be much >>>>>> appreciated. >>>>> >>>>> Can you please explain more about data truncation? I'm a little confused... >>>>> >>>>> Do you mean that f2fs doesn't allocate enough memory for zstd compression, >>>>> so that compression is not finished actually, the compressed data is truncated >>>>> at dst buffer? >>>> Hi Chao, >>>> I’ve tested F2FS using a benchmark I adapted from testing BtrFS [0]. It is possible >>>> that the script I’m using is buggy or is exposing an edge case in F2FS. The files >>>> that I copy to F2FS and compress end up truncated with a hole at the end. >>> >>> Thanks for your explanation. :) >>> >>>> It is based off of upstream commit ab29a807a7. >>>> E.g. the end of the copied file looks like this, but the original file has non-zero data >>>> In the end. Until the hole at the end the file is correct. >>>> od dickens | tail -n 5 >>>>> 46667760 067502 066167 020056 040440 020163 023511 006555 060412 >>>>> 46670000 000000 000000 000000 000000 000000 000000 000000 000000 >>>>> * >>>>> 46703060 000000 000000 000000 000000 000000 000000 000000 >>>>> 46703076 >>>> [0] https://gist.github.com/terrelln/7dd2919937dfbdb8e839e4ad11c81db4 >>> >>> Shouldn't we just get sha1 value by flitering sha1sum output? >>> >>> asha=`sha1sum $BENCHMARK_DIR/$file |awk {'print $1'}` >>> bsha=`sha1sum $MP/$i/$file |awk {'print $1'}` >> >> Probably, but it was just a quick one-off script. > > Ah, never mind, you are right. > >>> I can't reproduce this issue by using simple data sample, could you share >>> that 'dickens' file or other smaller-sized sample if you have? >> >> The /tmp/silesia directory in the example is populated with all the files from >> this website. It is a popular data compression benchmark corpus. You can >> click on the “total” link to download a zip archive of all the files. >> >> http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia >> >> -Nick > > I’ve spent some time minimizing the test case. This script [0] is the minimized > test case that doesn’t require any input files, it builds its own. > > Several observations: > * The input file needs to be 7700481 bytes large, smaller files don’t trigger the bug. > * You have to `chattr +c` the file after copying it otherwise the bug doesn’t occur. > * After `chattr +c` you have to unmount and remount the filesystem to trigger the bug. > > I’ve reproduced on v5.9-rc5 (856deb866d16e). I’ve also reproduced on my host machine > running 5.8.5-arch1-1. > > [0] https://gist.github.com/terrelln/4bba325abdfa3a6f014e9911ac92a185 Ah, I got it. Step of enabling compressed inode is not correct, we should touch an empty file, and then use 'chattr +c' on that file to enable compression, otherwise the race condition could be complicated to handle. So we need below diff to disallow setting compression flag on an non-empty file: diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 8a422400e824..b462db7898fd 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1836,6 +1836,8 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask) if (iflags & F2FS_COMPR_FL) { if (!f2fs_may_compress(inode)) return -EINVAL; + if (get_dirty_pages(inode) || fi->i_compr_blocks) + return -EINVAL; set_compress_context(inode); } Could you adjust your script and retest? touch $DST_FILE chattr +c $DST_FILE cp $SRC_FILE $DST_FILE Thanks, > > Best, > Nick > >>> Thanks, >>> >>>> Best, >>>> Nick >>>>> Thanks, >>>>> >>>>>> Signed-off-by: Nick Terrell >>>>>> --- >>>>>> fs/f2fs/compress.c | 102 +++++++++++++++++---------------------------- >>>>>> 1 file changed, 38 insertions(+), 64 deletions(-) >>>>>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c >>>>>> index e056f3a2b404..b79efce81651 100644 >>>>>> --- a/fs/f2fs/compress.c >>>>>> +++ b/fs/f2fs/compress.c >>>>>> @@ -11,7 +11,8 @@ >>>>>> #include >>>>>> #include >>>>>> #include >>>>>> -#include >>>>>> +#include >>>>>> +#include >>>>>> #include "f2fs.h" >>>>>> #include "node.h" >>>>>> @@ -298,21 +299,21 @@ static const struct f2fs_compress_ops f2fs_lz4_ops = { >>>>>> static int zstd_init_compress_ctx(struct compress_ctx *cc) >>>>>> { >>>>>> ZSTD_parameters params; >>>>>> - ZSTD_CStream *stream; >>>>>> + ZSTD_CCtx *ctx; >>>>>> void *workspace; >>>>>> unsigned int workspace_size; >>>>>> params = ZSTD_getParams(F2FS_ZSTD_DEFAULT_CLEVEL, cc->rlen, 0); >>>>>> - workspace_size = ZSTD_CStreamWorkspaceBound(params.cParams); >>>>>> + workspace_size = ZSTD_estimateCCtxSize_usingCParams(params.cParams); >>>>>> workspace = f2fs_kvmalloc(F2FS_I_SB(cc->inode), >>>>>> workspace_size, GFP_NOFS); >>>>>> if (!workspace) >>>>>> return -ENOMEM; >>>>>> - stream = ZSTD_initCStream(params, 0, workspace, workspace_size); >>>>>> - if (!stream) { >>>>>> - printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_initCStream failed\n", >>>>>> + ctx = ZSTD_initStaticCCtx(workspace, workspace_size); >>>>>> + if (!ctx) { >>>>>> + printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_inittaticCStream failed\n", >>>>>> KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id, >>>>>> __func__); >>>>>> kvfree(workspace); >>>>>> @@ -320,7 +321,7 @@ static int zstd_init_compress_ctx(struct compress_ctx *cc) >>>>>> } >>>>>> cc->private = workspace; >>>>>> - cc->private2 = stream; >>>>>> + cc->private2 = ctx; >>>>>> cc->clen = cc->rlen - PAGE_SIZE - COMPRESS_HEADER_SIZE; >>>>>> return 0; >>>>>> @@ -335,65 +336,48 @@ static void zstd_destroy_compress_ctx(struct compress_ctx *cc) >>>>>> static int zstd_compress_pages(struct compress_ctx *cc) >>>>>> { >>>>>> - ZSTD_CStream *stream = cc->private2; >>>>>> - ZSTD_inBuffer inbuf; >>>>>> - ZSTD_outBuffer outbuf; >>>>>> - int src_size = cc->rlen; >>>>>> - int dst_size = src_size - PAGE_SIZE - COMPRESS_HEADER_SIZE; >>>>>> - int ret; >>>>>> - >>>>>> - inbuf.pos = 0; >>>>>> - inbuf.src = cc->rbuf; >>>>>> - inbuf.size = src_size; >>>>>> - >>>>>> - outbuf.pos = 0; >>>>>> - outbuf.dst = cc->cbuf->cdata; >>>>>> - outbuf.size = dst_size; >>>>>> - >>>>>> - ret = ZSTD_compressStream(stream, &outbuf, &inbuf); >>>>>> - if (ZSTD_isError(ret)) { >>>>>> - printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_compressStream failed, ret: %d\n", >>>>>> - KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id, >>>>>> - __func__, ZSTD_getErrorCode(ret)); >>>>>> - return -EIO; >>>>>> - } >>>>>> - >>>>>> - ret = ZSTD_endStream(stream, &outbuf); >>>>>> + ZSTD_CCtx *ctx = cc->private2; >>>>>> + const size_t src_size = cc->rlen; >>>>>> + const size_t dst_size = src_size - PAGE_SIZE - COMPRESS_HEADER_SIZE; >>>>>> + ZSTD_parameters params = ZSTD_getParams(F2FS_ZSTD_DEFAULT_CLEVEL, src_size, 0); >>>>>> + size_t ret; >>>>>> + >>>>>> + ret = ZSTD_compress_advanced( >>>>>> + ctx, cc->cbuf->cdata, dst_size, cc->rbuf, src_size, NULL, 0, params); >>>>>> if (ZSTD_isError(ret)) { >>>>>> - printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_endStream returned %d\n", >>>>>> + /* >>>>>> + * there is compressed data remained in intermediate buffer due to >>>>>> + * no more space in cbuf.cdata >>>>>> + */ >>>>>> + if (ZSTD_getErrorCode(ret) == ZSTD_error_dstSize_tooSmall) >>>>>> + return -EAGAIN; >>>>>> + /* other compression errors return -EIO */ >>>>>> + printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_compress_advanced failed, err: %s\n", >>>>>> KERN_ERR, F2FS_I_SB(cc->inode)->sb->s_id, >>>>>> - __func__, ZSTD_getErrorCode(ret)); >>>>>> + __func__, ZSTD_getErrorName(ret)); >>>>>> return -EIO; >>>>>> } >>>>>> - /* >>>>>> - * there is compressed data remained in intermediate buffer due to >>>>>> - * no more space in cbuf.cdata >>>>>> - */ >>>>>> - if (ret) >>>>>> - return -EAGAIN; >>>>>> - >>>>>> - cc->clen = outbuf.pos; >>>>>> + cc->clen = ret; >>>>>> return 0; >>>>>> } >>>>>> static int zstd_init_decompress_ctx(struct decompress_io_ctx *dic) >>>>>> { >>>>>> - ZSTD_DStream *stream; >>>>>> + ZSTD_DCtx *ctx; >>>>>> void *workspace; >>>>>> unsigned int workspace_size; >>>>>> - workspace_size = ZSTD_DStreamWorkspaceBound(MAX_COMPRESS_WINDOW_SIZE); >>>>>> + workspace_size = ZSTD_estimateDCtxSize(); >>>>>> workspace = f2fs_kvmalloc(F2FS_I_SB(dic->inode), >>>>>> workspace_size, GFP_NOFS); >>>>>> if (!workspace) >>>>>> return -ENOMEM; >>>>>> - stream = ZSTD_initDStream(MAX_COMPRESS_WINDOW_SIZE, >>>>>> - workspace, workspace_size); >>>>>> - if (!stream) { >>>>>> - printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_initDStream failed\n", >>>>>> + ctx = ZSTD_initStaticDCtx(workspace, workspace_size); >>>>>> + if (!ctx) { >>>>>> + printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_initStaticDCtx failed\n", >>>>>> KERN_ERR, F2FS_I_SB(dic->inode)->sb->s_id, >>>>>> __func__); >>>>>> kvfree(workspace); >>>>>> @@ -401,7 +385,7 @@ static int zstd_init_decompress_ctx(struct decompress_io_ctx *dic) >>>>>> } >>>>>> dic->private = workspace; >>>>>> - dic->private2 = stream; >>>>>> + dic->private2 = ctx; >>>>>> return 0; >>>>>> } >>>>>> @@ -415,28 +399,18 @@ static void zstd_destroy_decompress_ctx(struct decompress_io_ctx *dic) >>>>>> static int zstd_decompress_pages(struct decompress_io_ctx *dic) >>>>>> { >>>>>> - ZSTD_DStream *stream = dic->private2; >>>>>> - ZSTD_inBuffer inbuf; >>>>>> - ZSTD_outBuffer outbuf; >>>>>> - int ret; >>>>>> - >>>>>> - inbuf.pos = 0; >>>>>> - inbuf.src = dic->cbuf->cdata; >>>>>> - inbuf.size = dic->clen; >>>>>> - >>>>>> - outbuf.pos = 0; >>>>>> - outbuf.dst = dic->rbuf; >>>>>> - outbuf.size = dic->rlen; >>>>>> + ZSTD_DCtx *ctx = dic->private2; >>>>>> + size_t ret; >>>>>> - ret = ZSTD_decompressStream(stream, &outbuf, &inbuf); >>>>>> + ret = ZSTD_decompressDCtx(ctx, dic->rbuf, dic->rlen, dic->cbuf->cdata, dic->clen); >>>>>> if (ZSTD_isError(ret)) { >>>>>> - printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_compressStream failed, ret: %d\n", >>>>>> + printk_ratelimited("%sF2FS-fs (%s): %s ZSTD_decompressDCtx failed, err: %s\n", >>>>>> KERN_ERR, F2FS_I_SB(dic->inode)->sb->s_id, >>>>>> - __func__, ZSTD_getErrorCode(ret)); >>>>>> + __func__, ZSTD_getErrorName(ret)); >>>>>> return -EIO; >>>>>> } >>>>>> - if (dic->rlen != outbuf.pos) { >>>>>> + if (dic->rlen != ret) { >>>>>> printk_ratelimited("%sF2FS-fs (%s): %s ZSTD invalid rlen:%zu, " >>>>>> "expected:%lu\n", KERN_ERR, >>>>>> F2FS_I_SB(dic->inode)->sb->s_id, >