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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B86E3C624D6 for ; Tue, 1 Sep 2026 13:13:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=bLJ7so2eQ04eUxA7uRgkuQiNgLyO0A/w5Eo0GY7ooL8=; b=AVsG5P+4tj6CYsrK/0yoxIz9dA hRP86ze2wvk19EpDAjB11XFp8ENDLKttof4T+js7igudpgJPHpEOjD5NGtYgXkjkJ2WYUx4rb4J29 mr+XlqIQPadBd4DiVHyiT5yTNQm/742lEYylRqqsTMt5Xl8+YxgQckMDlaQ0midBuf1ZlZH1+H9Vk M89RMlxS2zPNqyJAFDxYhGAwvUUav7k0hu351X/6YT6RGi4V0BwL6p1BDS5DdfAE300ONqIDdIaxq 2pGfcloH93PUHV/BbdM3GSywfu/IXixomzmlPz6WWakpjR6uQnsR99SfK5DGp+qdgUhmXgo9ne9I8 F/kdaurQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1OIX-0000000CAbw-20SJ; Tue, 01 Sep 2026 13:13:09 +0000 Received: from canpmsgout04.his.huawei.com ([113.46.200.219]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1OIQ-0000000CAUZ-0ffV; Tue, 01 Sep 2026 13:13:05 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=bLJ7so2eQ04eUxA7uRgkuQiNgLyO0A/w5Eo0GY7ooL8=; b=xTyBELc/cInYBPOUaTwt3ILOfZ8Pf1/HI1d647R/Wj1c7mrsUsFgGo6dMICOPm6/A2FvA1OPa OLpDQ8pLDW77LCeJ/wMWwQZwTA8vs7oqYp02u/NAFMCA1JTKhXa+1DFZkbttwNYqEJRvMcS+5Dk X8P9UZhgp21LbdrV9BHtios= Received: from mail.maildlp.com (unknown [172.19.162.197]) by canpmsgout04.his.huawei.com (SkyGuard) with ESMTPS id 4hZ5bz1vPzz1prLc; Tue, 1 Sep 2026 21:02:07 +0800 (CST) Received: from dggpemr100018.china.huawei.com (unknown [7.185.36.64]) by mail.maildlp.com (Postfix) with ESMTPS id 7E33440579; Tue, 1 Sep 2026 21:12:58 +0800 (CST) Received: from huawei.com (10.50.85.155) by dggpemr100018.china.huawei.com (7.185.36.64) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Tue, 1 Sep 2026 21:12:57 +0800 From: zhouminqiang To: , , , , , CC: , , , , , , Subject: [PATCH v3 8/8] jffs2: add runtime toggle for write verification Date: Tue, 1 Sep 2026 21:05:49 +0800 Message-ID: <20260901130549.1761342-9-zhouminqiang2@huawei.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260901130549.1761342-1-zhouminqiang2@huawei.com> References: <20260901130549.1761342-1-zhouminqiang2@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.50.85.155] X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To dggpemr100018.china.huawei.com (7.185.36.64) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260901_061302_552664_D9CC72A0 X-CRM114-Status: GOOD ( 12.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Write verification is a diagnostic facility that adds read-back overhead to every write. In production, this overhead is undesirable unless fault isolation is required. Add a module parameter jffs2.write_verify (bool, 0644) that defaults to off when CONFIG_JFFS2_FS_WRITE_VERIFY is enabled. The verification entry checks READ_ONCE(jffs2_write_verify) and returns immediately when disabled, avoiding any overhead. The parameter can be toggled at runtime via /sys/module/jffs2/parameters/write_verify or set at boot/modprobe time. Signed-off-by: zhouminqiang --- fs/jffs2/Kconfig | 8 ++++++++ fs/jffs2/writev.c | 23 +++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/fs/jffs2/Kconfig b/fs/jffs2/Kconfig index 556025a5d438..03dadbd003cd 100644 --- a/fs/jffs2/Kconfig +++ b/fs/jffs2/Kconfig @@ -61,6 +61,14 @@ config JFFS2_FS_WRITE_VERIFY tell transport/program-time corruption from post-commit media damage. + Verification defaults to off when this option is selected and can + be enabled at runtime via sysfs: + + /sys/module/jffs2/parameters/write_verify + + Write 0 to disable, 1 to enable. Boot/modprobe parameter + jffs2.write_verify=0|1 is also supported. + If unsure, say 'N'. config JFFS2_SUMMARY diff --git a/fs/jffs2/writev.c b/fs/jffs2/writev.c index 604a14bb5710..342c413be95c 100644 --- a/fs/jffs2/writev.c +++ b/fs/jffs2/writev.c @@ -9,12 +9,32 @@ * */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include +#include #include #include #include "nodelist.h" #ifdef CONFIG_JFFS2_FS_WRITE_VERIFY +/* + * Optional read-back after writes. + * + * Catch cases where data is corrupted after node CRCs are calculated but + * before it is correctly programmed -- e.g. in RAM or during DMA/bus + * transfer to the flash controller -- so mtd_write() succeeds while the + * medium does not match the in-memory image. + * + * Runtime toggle: /sys/module/jffs2/parameters/write_verify + * (also boot/modprobe: jffs2.write_verify=0|1) + */ +static bool jffs2_write_verify; +module_param_named(write_verify, jffs2_write_verify, bool, 0644); +MODULE_PARM_DESC(write_verify, + "Verify flash writes by reading back (default: N)"); + + int jffs2_verify_write(struct jffs2_sb_info *c, const unsigned char *buf, uint32_t ofs, size_t len) { @@ -23,6 +43,9 @@ int jffs2_verify_write(struct jffs2_sb_info *c, const unsigned char *buf, char *eccstr; void *verify_buf; + if (!READ_ONCE(jffs2_write_verify)) + return 0; + verify_buf = kmalloc(len, GFP_NOFS | __GFP_NOWARN); if (!verify_buf) { pr_warn("%s(): verify buffer allocation failed, skipping verification\n", -- 2.52.0