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 9D987C433F5 for ; Tue, 11 Jan 2022 13:56:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241178AbiAKN41 convert rfc822-to-8bit (ORCPT ); Tue, 11 Jan 2022 08:56:27 -0500 Received: from lithops.sigma-star.at ([195.201.40.130]:49494 "EHLO lithops.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241195AbiAKN40 (ORCPT ); Tue, 11 Jan 2022 08:56:26 -0500 Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 74D6962DA5E2; Tue, 11 Jan 2022 14:56:24 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id YLrS9tLm1LzN; Tue, 11 Jan 2022 14:56:23 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 2400C62DA609; Tue, 11 Jan 2022 14:56:23 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id xPuhK_heLKGY; Tue, 11 Jan 2022 14:56:23 +0100 (CET) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lithops.sigma-star.at (Postfix) with ESMTP id EC97562DA5E2; Tue, 11 Jan 2022 14:56:22 +0100 (CET) Date: Tue, 11 Jan 2022 14:56:22 +0100 (CET) From: Richard Weinberger To: chengzhihao1 Cc: Miquel Raynal , Vignesh Raghavendra , mcoquelin stm32 , kirill shutemov , Sascha Hauer , linux-mtd , linux-kernel Message-ID: <1492514284.249466.1641909382867.JavaMail.zimbra@nod.at> In-Reply-To: <0a7a5cce-1ee1-70b6-d368-615dfa0a617a@huawei.com> References: <20211227032246.2886878-1-chengzhihao1@huawei.com> <20211227032246.2886878-13-chengzhihao1@huawei.com> <361758697.248157.1641857025490.JavaMail.zimbra@nod.at> <6f7df7ba-9557-58a3-7978-e5d14a72f234@huawei.com> <244238061.248369.1641886066066.JavaMail.zimbra@nod.at> <420c7567-8926-2e8b-4da0-a9bfc8379642@huawei.com> <11976804.249069.1641902225370.JavaMail.zimbra@nod.at> <0a7a5cce-1ee1-70b6-d368-615dfa0a617a@huawei.com> Subject: Re: [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [195.201.40.130] X-Mailer: Zimbra 8.8.12_GA_3807 (ZimbraWebClient - FF95 (Linux)/8.8.12_GA_3809) Thread-Topic: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 Thread-Index: 86Vvr6wU5AK+5c62IIyzK5YFzlh8mg== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Ursprüngliche Mail ----- > Von: "chengzhihao1" > An: "richard" > CC: "Miquel Raynal" , "Vignesh Raghavendra" , "mcoquelin stm32" > , "kirill shutemov" , "Sascha Hauer" > , "linux-mtd" , "linux-kernel" > Gesendet: Dienstag, 11. Januar 2022 14:23:52 > Betreff: Re: [PATCH v6 12/15] ubi: fastmap: Add all fastmap pebs into 'ai->fastmap' when fm->used_blocks>=2 > 在 2022/1/11 19:57, Richard Weinberger 写道: >> ubi_wl_init() is called in both cases, with and without fastmap. > I agree. > >> And ai->fastmap contains all anchor PEBs that scan_fast() found. >> This can be the most recent but also outdated anchor PEBs. > Is it exists a case that outdated fastmap PEBs are neither counted into > 'fmhdr->erase_peb_count' nor scanned into 'ai->fastmap' after attaching > by fastmap. > [...] > I think UBI attaches failed by fastmap if kernel goes here. > 1870 err = erase_aeb(ubi, aeb, sync); Hmm, I think the paranoia check in fastmap.c is too strict these days. if (WARN_ON(count_fastmap_pebs(ai) != ubi->peb_count - ai->bad_peb_count - fm->used_blocks)) goto fail_bad; It does not account ai->fastmap. So if ai->fastmap contains old anchor PEBs this check will trigger and force falling back to scanning mode. With this check fixed, ubi_wl_init() will erase all old PEBs from ai->fastmap. So I agree that this code path is wonky and can be cleaned up. But please be extremely careful and give all your changes excessive testing with real workload and power-cuts. Thanks, //richard