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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 96B89C4338F for ; Wed, 4 Aug 2021 03:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F19461040 for ; Wed, 4 Aug 2021 03:33:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234388AbhHDDdQ (ORCPT ); Tue, 3 Aug 2021 23:33:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:60986 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229571AbhHDDdO (ORCPT ); Tue, 3 Aug 2021 23:33:14 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 81E5D61037; Wed, 4 Aug 2021 03:33:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628047982; bh=L4lrzLbH/aV3W5MjROtpuPqG8ncWOO07RWA08kmI+ts=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=YFUuXXyxGoUyT/b0+YHP3RTRGNkE+kReB/vVxSbZ9sv/8Vuip8FzQgUGMK/AZrmnt QSVtIyrxIGicFU7jbEp6fBH+dXKLBhMtr0o12DNRs4d7RapJG/F7KveUqSJgm8NCCv Lvzcn6+28XC6Vc2F13mb5tu2I+4p8hHCdAyDYK9z5C4NBry6n3+hAhoGxLBcKC0zNc Mc+ziXtOOHrqwh9zBbeE4zZ2U9EB3dx4kxGR+sqL3Cq+68gLDq9Chf0ug8cEg2FzRJ q8+ebDbGgtLc6n75TobFfTL1rzI8YEzC6shta9zzjDbU/SM2i+3fKAVKOKwwl/LAnn r+3xLXV9TxERg== Subject: Re: [PATCH v3] f2fs: Reduce the scope of setting fsck tag when de->name_len is zero To: =?UTF-8?B?5p2O5oms6Z+s?= Cc: jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: From: Chao Yu Message-ID: <2c59c14b-008c-aee9-6775-13b47fbd252f@kernel.org> Date: Wed, 4 Aug 2021 11:32:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Yangtao, I did some cleanup in your patch, and resend for you, please note that. :) Thanks, On 2021/7/20 20:31, 李扬韬 wrote: > HI Chao， > > From: Chao Yu > Date: 2021-07-20 18:23:15 > To: Yangtao Li ,jaegeuk@kernel.org > Cc: linux-f2fs-devel@lists.sourceforge.net,linux-kernel@vger.kernel.org > Subject: Re: [PATCH v3] f2fs: Reduce the scope of setting fsck tag when de->name_len is zero>On 2021/7/20 15:06, Yangtao Li wrote: >>> I recently found a case where de->name_len is 0 in f2fs_fill_dentries() easily reproduced, >>> and finally set the fsck flag. >>> >>> Thread A Thread B >>> >>> f2fs_readdir >>> f2fs_read_inline_dir >>> ctx->pos = d.max >>> f2fs_add_dentry >>> f2fs_add_inline_entry >>> do_convert_inline_dir >>> f2fs_add_regular_entry >>> f2fs_readdir >>> f2fs_fill_dentries >>> set_sbi_flag(sbi, SBI_NEED_FSCK) >>> >>> Process A opens the folder, and has been reading without closing it. During this period, >>> Process B created a file under the folder (occupying multiple f2fs_dir_entry, exceeding >>> the d.max of the inline dir). After creation, process A uses the d.max of inline dir to >>> read it again, and it will read that de->name_len is 0. >>> >>> And Chao pointed out that w/o inline conversion, the race condition still can happen as below >>> >>> dir_entry1: A >>> dir_entry2: B >>> dir_entry3: C >>> free slot: _ >>> ctx->pos: ^ >>> >>> Before: >>> AAAABBBB___ >>> ^ >> >> please use blank instead of tab before '^' > > I don't know exactly what happened. In fact, in v2, spaces were used. Then it was changed to tab in v3. > >> >>> Thread B delete dir_entry2, and create dir_entry3. >>> >>> After: >>> AAAACCCCC__ >>> ^ >> >> Ditto >> >>> >>> In these scenarios, the file system is not damaged, and it's hard to avoid it. But we can bypass >>> tagging FSCK flag if: >>> a) bit_pos (:= ctx->pos % d->max) is non-zero & b) before bit_pos moves to first >>> valid dir_entry. >>> >>> Signed-off-by: Yangtao Li >>> --- >>> fs/f2fs/dir.c | 14 +++++++++----- >>> 1 file changed, 9 insertions(+), 5 deletions(-) >>> >>> diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c >>> index 456651682daf..bfe942733b5e 100644 >>> --- a/fs/f2fs/dir.c >>> +++ b/fs/f2fs/dir.c >>> @@ -1000,6 +1000,7 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d, >>> struct f2fs_sb_info *sbi = F2FS_I_SB(d->inode); >>> struct blk_plug plug; >>> bool readdir_ra = sbi->readdir_ra == 1; >>> + bool found_valid_dirent = false; >> >> One more blank before '='. >> >> bool found_valid_dirent = false; >> > > OK. > > Thx， > > > 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=-15.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,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 D5F43C4338F for ; Wed, 4 Aug 2021 03:33:22 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8235560F56; Wed, 4 Aug 2021 03:33:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8235560F56 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1mB7ek-0007Tl-3S; Wed, 04 Aug 2021 03:33:22 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mB7ej-0007TY-0i for linux-f2fs-devel@lists.sourceforge.net; Wed, 04 Aug 2021 03:33:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=BtkNYftmu/wU0jTQuU56pcA94b/2ORJBNmcWCAWopEE=; b=TKN1nDoZkAHr6iEPpVf6MsupTk wsavUTimTK+UoDuQu4okxqE9wzUnAa6aKtNMn4Cdwb+YqPIt+TsQh0gqAKlddGpHx8I5ToioPfrmC ct4EInoRY0O9hY0WcJZ+0dFkgTmy+y44F7wAvp6F9eUh5PwmVnIdiME9mRgjXqZrHmts=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:Subject:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=BtkNYftmu/wU0jTQuU56pcA94b/2ORJBNmcWCAWopEE=; b=X7FZzvhB4loqbnPFSPwzKvAeLJ vHyetiZMPKtcAjSIof6ccTAbEL9dxBvr2NcMm6nGo2h51QI3hETGNyRqnKvW2yPZ+dSTxrQw2Knmo 48voXxhDEmm8hXadMLfs321ptymBnCay2ndTvMbxCpv7Tj0lYmYGRP2VDJdAVSAxELcc=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) id 1mB7ea-0001kV-PJ for linux-f2fs-devel@lists.sourceforge.net; Wed, 04 Aug 2021 03:33:20 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 81E5D61037; Wed, 4 Aug 2021 03:33:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628047982; bh=L4lrzLbH/aV3W5MjROtpuPqG8ncWOO07RWA08kmI+ts=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=YFUuXXyxGoUyT/b0+YHP3RTRGNkE+kReB/vVxSbZ9sv/8Vuip8FzQgUGMK/AZrmnt QSVtIyrxIGicFU7jbEp6fBH+dXKLBhMtr0o12DNRs4d7RapJG/F7KveUqSJgm8NCCv Lvzcn6+28XC6Vc2F13mb5tu2I+4p8hHCdAyDYK9z5C4NBry6n3+hAhoGxLBcKC0zNc Mc+ziXtOOHrqwh9zBbeE4zZ2U9EB3dx4kxGR+sqL3Cq+68gLDq9Chf0ug8cEg2FzRJ q8+ebDbGgtLc6n75TobFfTL1rzI8YEzC6shta9zzjDbU/SM2i+3fKAVKOKwwl/LAnn r+3xLXV9TxERg== To: =?UTF-8?B?5p2O5oms6Z+s?= References: From: Chao Yu Message-ID: <2c59c14b-008c-aee9-6775-13b47fbd252f@kernel.org> Date: Wed, 4 Aug 2021 11:32:59 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Headers-End: 1mB7ea-0001kV-PJ Subject: Re: [f2fs-dev] [PATCH v3] f2fs: Reduce the scope of setting fsck tag when de->name_len is zero X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jaegeuk@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net SGVsbG8sIFlhbmd0YW8sCgpJIGRpZCBzb21lIGNsZWFudXAgaW4geW91ciBwYXRjaCwgYW5kIHJl c2VuZCBmb3IgeW91LCBwbGVhc2UKbm90ZSB0aGF0LiA6KQoKVGhhbmtzLAoKT24gMjAyMS83LzIw IDIwOjMxLCDmnY7miazpn6wgd3JvdGU6Cj4gSEkgQ2hhb++8jAo+IAo+IEZyb206IENoYW8gWXUg PGNoYW9Aa2VybmVsLm9yZz4KPiBEYXRlOiAyMDIxLTA3LTIwIDE4OjIzOjE1Cj4gVG86ICBZYW5n dGFvIExpIDxmcmFuay5saUB2aXZvLmNvbT4samFlZ2V1a0BrZXJuZWwub3JnCj4gQ2M6ICBsaW51 eC1mMmZzLWRldmVsQGxpc3RzLnNvdXJjZWZvcmdlLm5ldCxsaW51eC1rZXJuZWxAdmdlci5rZXJu ZWwub3JnCj4gU3ViamVjdDogUmU6IFtQQVRDSCB2M10gZjJmczogUmVkdWNlIHRoZSBzY29wZSBv ZiBzZXR0aW5nIGZzY2sgdGFnIHdoZW4gZGUtPm5hbWVfbGVuIGlzIHplcm8+T24gMjAyMS83LzIw IDE1OjA2LCBZYW5ndGFvIExpIHdyb3RlOgo+Pj4gSSByZWNlbnRseSBmb3VuZCBhIGNhc2Ugd2hl cmUgZGUtPm5hbWVfbGVuIGlzIDAgaW4gZjJmc19maWxsX2RlbnRyaWVzKCkgZWFzaWx5IHJlcHJv ZHVjZWQsCj4+PiBhbmQgZmluYWxseSBzZXQgdGhlIGZzY2sgZmxhZy4KPj4+Cj4+PiBUaHJlYWQg QQkJCQkJVGhyZWFkIEIKPj4+Cj4+PiBmMmZzX3JlYWRkaXIKPj4+IAlmMmZzX3JlYWRfaW5saW5l X2Rpcgo+Pj4gCQljdHgtPnBvcyA9IGQubWF4Cj4+PiAJCQkJCQlmMmZzX2FkZF9kZW50cnkKPj4+ IAkJCQkJCQlmMmZzX2FkZF9pbmxpbmVfZW50cnkKPj4+IAkJCQkJCQkJZG9fY29udmVydF9pbmxp bmVfZGlyCj4+PiAJCQkJCQkJZjJmc19hZGRfcmVndWxhcl9lbnRyeQo+Pj4gZjJmc19yZWFkZGly Cj4+PiAJZjJmc19maWxsX2RlbnRyaWVzCj4+PiAJCXNldF9zYmlfZmxhZyhzYmksIFNCSV9ORUVE X0ZTQ0spCj4+Pgo+Pj4gUHJvY2VzcyBBIG9wZW5zIHRoZSBmb2xkZXIsIGFuZCBoYXMgYmVlbiBy ZWFkaW5nIHdpdGhvdXQgY2xvc2luZyBpdC4gRHVyaW5nIHRoaXMgcGVyaW9kLAo+Pj4gUHJvY2Vz cyBCIGNyZWF0ZWQgYSBmaWxlIHVuZGVyIHRoZSBmb2xkZXIgKG9jY3VweWluZyBtdWx0aXBsZSBm MmZzX2Rpcl9lbnRyeSwgZXhjZWVkaW5nCj4+PiB0aGUgZC5tYXggb2YgdGhlIGlubGluZSBkaXIp LiBBZnRlciBjcmVhdGlvbiwgcHJvY2VzcyBBIHVzZXMgdGhlIGQubWF4IG9mIGlubGluZSBkaXIg dG8KPj4+IHJlYWQgaXQgYWdhaW4sIGFuZCBpdCB3aWxsIHJlYWQgdGhhdCBkZS0+bmFtZV9sZW4g aXMgMC4KPj4+Cj4+PiBBbmQgQ2hhbyBwb2ludGVkIG91dCB0aGF0IHcvbyBpbmxpbmUgY29udmVy c2lvbiwgdGhlIHJhY2UgY29uZGl0aW9uIHN0aWxsIGNhbiBoYXBwZW4gYXMgYmVsb3cKPj4+Cj4+ PiBkaXJfZW50cnkxOiBBCj4+PiBkaXJfZW50cnkyOiBCCj4+PiBkaXJfZW50cnkzOiBDCj4+PiBm cmVlIHNsb3Q6IF8KPj4+IGN0eC0+cG9zOiBeCj4+Pgo+Pj4gQmVmb3JlOgo+Pj4gQUFBQUJCQkJf X18KPj4+IAkgXgo+Pgo+PiBwbGVhc2UgdXNlIGJsYW5rIGluc3RlYWQgb2YgdGFiIGJlZm9yZSAn XicKPiAKPiBJIGRvbid0IGtub3cgZXhhY3RseSB3aGF0IGhhcHBlbmVkLiBJbiBmYWN0LCBpbiB2 Miwgc3BhY2VzIHdlcmUgdXNlZC4gVGhlbiBpdCB3YXMgY2hhbmdlZCB0byB0YWIgaW4gdjMuCj4g Cj4+Cj4+PiBUaHJlYWQgQiBkZWxldGUgZGlyX2VudHJ5MiwgYW5kIGNyZWF0ZSBkaXJfZW50cnkz Lgo+Pj4KPj4+IEFmdGVyOgo+Pj4gQUFBQUNDQ0NDX18KPj4+IAkgXgo+Pgo+PiBEaXR0bwo+Pgo+ Pj4KPj4+IEluIHRoZXNlIHNjZW5hcmlvcywgdGhlIGZpbGUgc3lzdGVtIGlzIG5vdCBkYW1hZ2Vk LCBhbmQgaXQncyBoYXJkIHRvIGF2b2lkIGl0LiBCdXQgd2UgY2FuIGJ5cGFzcwo+Pj4gdGFnZ2lu ZyBGU0NLIGZsYWcgaWY6Cj4+PiBhKSBiaXRfcG9zICg6PSBjdHgtPnBvcyAlIGQtPm1heCkgaXMg bm9uLXplcm8gJiBiKSBiZWZvcmUgYml0X3BvcyBtb3ZlcyB0byBmaXJzdAo+Pj4gdmFsaWQgZGly X2VudHJ5Lgo+Pj4KPj4+IFNpZ25lZC1vZmYtYnk6IFlhbmd0YW8gTGkgPGZyYW5rLmxpQHZpdm8u Y29tPgo+Pj4gLS0tCj4+PiAgICBmcy9mMmZzL2Rpci5jIHwgMTQgKysrKysrKysrLS0tLS0KPj4+ ICAgIDEgZmlsZSBjaGFuZ2VkLCA5IGluc2VydGlvbnMoKyksIDUgZGVsZXRpb25zKC0pCj4+Pgo+ Pj4gZGlmZiAtLWdpdCBhL2ZzL2YyZnMvZGlyLmMgYi9mcy9mMmZzL2Rpci5jCj4+PiBpbmRleCA0 NTY2NTE2ODJkYWYuLmJmZTk0MjczM2I1ZSAxMDA2NDQKPj4+IC0tLSBhL2ZzL2YyZnMvZGlyLmMK Pj4+ICsrKyBiL2ZzL2YyZnMvZGlyLmMKPj4+IEBAIC0xMDAwLDYgKzEwMDAsNyBAQCBpbnQgZjJm c19maWxsX2RlbnRyaWVzKHN0cnVjdCBkaXJfY29udGV4dCAqY3R4LCBzdHJ1Y3QgZjJmc19kZW50 cnlfcHRyICpkLAo+Pj4gICAgCXN0cnVjdCBmMmZzX3NiX2luZm8gKnNiaSA9IEYyRlNfSV9TQihk LT5pbm9kZSk7Cj4+PiAgICAJc3RydWN0IGJsa19wbHVnIHBsdWc7Cj4+PiAgICAJYm9vbCByZWFk ZGlyX3JhID0gc2JpLT5yZWFkZGlyX3JhID09IDE7Cj4+PiArCWJvb2wgZm91bmRfdmFsaWRfZGly ZW50ICA9IGZhbHNlOwo+Pgo+PiBPbmUgbW9yZSBibGFuayBiZWZvcmUgJz0nLgo+Pgo+PiBib29s IGZvdW5kX3ZhbGlkX2RpcmVudCA9IGZhbHNlOwo+Pgo+IAo+IE9LLgo+IAo+IFRoeO+8jAo+IAo+ IAo+IAoKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCkxp bnV4LWYyZnMtZGV2ZWwgbWFpbGluZyBsaXN0CkxpbnV4LWYyZnMtZGV2ZWxAbGlzdHMuc291cmNl Zm9yZ2UubmV0Cmh0dHBzOi8vbGlzdHMuc291cmNlZm9yZ2UubmV0L2xpc3RzL2xpc3RpbmZvL2xp bnV4LWYyZnMtZGV2ZWwK