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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81B6CC77B7E for ; Mon, 29 May 2023 10:19:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232034AbjE2KTC (ORCPT ); Mon, 29 May 2023 06:19:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229613AbjE2KSz (ORCPT ); Mon, 29 May 2023 06:18:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FB84F1 for ; Mon, 29 May 2023 03:18:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EBDBB61362 for ; Mon, 29 May 2023 10:18:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12796C433EF; Mon, 29 May 2023 10:18:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1685355527; bh=RkkExfeGgE+dhRU4IGRx6ehNzHPNh6PhoYcLpUyFzMI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=EBu2mW4E1yMU8iIDd4Lsgo3CNSYIPG4uTB/mjzlxd2YqoaGca4QM+mdVQ/qTNc/vF cWUAaT0p7TiBZkLpAnoXjTeePD16OC1NU32Q2lnnOnrGAU1ZtpGb/vLR4Ic2j/HeBC iIjYaeOzE+mj3C69hZB8e+Q2KscKbLuw+XJQUoEP6NUflbUdLXnCuxL+AbQYeDsy4T /+9j4eS+H4Kio8/TAVCSwgj9g5K5b4fEN3uTJ2E3ATnThp43OByH8ujoYHRIsYmYep 10Mle5BiZoD+tFRMmkCqnEnJ2suCWRq01NYGj5NuIfsA/YWMepSyjK5HzGm8rta0GT RIC3Va/1Vlnig== Message-ID: <0c15c662-903c-3504-d502-72f0a3b70cbf@kernel.org> Date: Mon, 29 May 2023 18:18:42 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [f2fs-dev] [PATCH 1/1] f2fs: fix args passed to trace_f2fs_lookup_end Content-Language: en-US To: Wu Bo Cc: jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, wubo.oduw@gmail.com References: <2bb05623-9438-3b68-6ac8-4294f9676ff6@kernel.org> <20230529041337.36741-1-bo.wu@vivo.com> From: Chao Yu In-Reply-To: <20230529041337.36741-1-bo.wu@vivo.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/5/29 12:13, Wu Bo wrote: > On Sat, May 27, 2023 at 09:01:41AM +0800, Chao Yu wrote: >> On 2023/5/27 1:21, Jaegeuk Kim wrote: >>> On 05/24, Wu Bo wrote: >>>> The NULL return of 'd_splice_alias' dosen't mean error. >>>> >>>> Signed-off-by: Wu Bo >>>> --- >>>> fs/f2fs/namei.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c >>>> index 77a71276ecb1..e5a3e39ce90c 100644 >>>> --- a/fs/f2fs/namei.c >>>> +++ b/fs/f2fs/namei.c >>>> @@ -577,7 +577,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry, >>>> #endif >>>> new = c(inode, dentry); >>>> err = PTR_ERR_OR_ZERO(new); >>>> - trace_f2fs_lookup_end(dir, dentry, ino, !new ? -ENOENT : err); >>>> + trace_f2fs_lookup_end(dir, new ? new : dentry, ino, err); >>> >>> Shouldn't give an error pointer to the dentry field. >>> >>> How about just giving the err? >>> >>> - err = PTR_ERR_OR_ZERO(new); >>> - trace_f2fs_lookup_end(dir, dentry, ino, !new ? -ENOENT : err); >>> + trace_f2fs_lookup_end(dir, dentry, ino, PTR_ERR_OR_ZERO(new)); >> >> static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr) >> { >> if (IS_ERR(ptr)) >> return PTR_ERR(ptr); >> else >> return 0; >> } >> >> For below two cases, PTR_ERR_OR_ZERO(new) will return zero: >> a) f2fs_lookup found existed dentry >> b) f2fs_lookup didn't find existed dentry (-ENOENT case) >> >> So in below commit, I passed -ENOENT to tracepoint for case b), so we can >> distinguish result of f2fs_lookup in tracepoint, actually, -ENOENT is expected >> value when we create a new file/directory. >> >> Commit 84597b1f9b05 ("f2fs: fix wrong value of tracepoint parameter") > I can see this commit is try to distinguish the dentry not existed case. > But a normal case which dentry is exactly found will also go through > 'd_splice_alias', and its return is also NULL. This makes the tracepoint always > print 'err:-2' like the following: > ls-11676 [004] .... 329281.943118: f2fs_lookup_end: dev = (254,39), pino = 4451, name:Alarms, ino:7093, err:-2 > ls-11676 [004] .... 329281.943145: f2fs_lookup_end: dev = (254,39), pino = 4451, name:Notifications, ino:7094, err:-2 > ls-11676 [004] .... 329281.943172: f2fs_lookup_end: dev = (254,39), pino = 4451, name:Pictures, ino:7095, err:-2 > Even these lookup are acctually successful, this is a bit strange. Ah, I misunderstand return value's meaning of .lookup. So, how about this? it only update err if d_splice_alias() returns a negative value? if (IS_ERR(new)) err = PTR_ERR(new); trace_f2fs_lookup_end(dir, new ? new : dentry, ino, err); Thanks, >> >>> >>> >>>> return new; >>>> out_iput: >>>> iput(inode); >>>> -- >>>> 2.35.3 >> >> >> _______________________________________________ >> Linux-f2fs-devel mailing list >> Linux-f2fs-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel