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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 D6874C61DCB for ; Sat, 29 Aug 2026 07:54:37 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4hX6wX2cTJz2xq0; Sat, 29 Aug 2026 17:54:36 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=45.249.212.187 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1787985847; cv=none; b=kbpXd1PF9/6dB1eLHWDm9OCjTs+yoWdZyERwT2ocGBBCVu1CfbfjOH3oz8unm4yfeOXxIft7m2CibHU/8egemox2UWhc0+7b/JVUEsBfcAjBEQv5NnyMzYLG/iHNQatrYgRnc2I94qxJdUlNkIIQlEtXuPVY+Oz28PBKv458TviqS9MLqKcHgrKp46M2OuEJdx+UbTd2zS+J/iwaNRgBWUrusAzQpY0osaOR/oOA8rj8EJ9BuwXvQzeEi4Tp0I3QFZFg+7pL9SQOAMHLMXtbV7VSakpejk22od6pU8cOAj4knYWw0u/ZuvQncxq/xGa0mPP2psxIopgCz1mN/euDxA== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1787985847; c=relaxed/relaxed; bh=TJPANoRDN+fYMKpdt+JU9S3bLccMRqCiof0MgFwWlzU=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OQpzoG484cfMBcOhyocYq9NHArfSR6IcV0386IEB1uZOuP6qSwYJ5tcxchVPuUIZzc9AZ49+w9rOVjRh1FuMwnYOnOQVdDDXu3dQky/fhVSSrabdiTqKUXfhB4RmoUX1UTCa+aKICG7ugYMj0CgMeCEPqgDdO+c83sPpyJuJfP96Dby5/O/LxCyyrjs56bSJVd59ZMYG5aELXgZfqN+u0eNrA29l6RU6EQSm6gOyGTI49IcRJHV/Yr1+m4y88suJ9rr9TSMeHUkPTZV2GzpBbjrCfnwXjeUP0OFLDvryuAc7PfYYPNayM/hfHCQicim9AnWsztnBCuDrv+NrFVkI9A== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; dkim=pass (1024-bit key; unprotected) header.d=huawei.com header.i=@huawei.com header.a=rsa-sha256 header.s=dkim header.b=e1y7l4Ph; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.a=rsa-sha256 header.s=dkim header.b=e1y7l4Ph; dkim-atps=neutral; spf=pass (client-ip=45.249.212.187; helo=szxga01-in.huawei.com; envelope-from=zhouminqiang2@huawei.com; receiver=lists.ozlabs.org) smtp.mailfrom=huawei.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=huawei.com header.i=@huawei.com header.a=rsa-sha256 header.s=dkim header.b=e1y7l4Ph; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.a=rsa-sha256 header.s=dkim header.b=e1y7l4Ph; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=huawei.com (client-ip=45.249.212.187; helo=szxga01-in.huawei.com; envelope-from=zhouminqiang2@huawei.com; receiver=lists.ozlabs.org) X-Greylist: delayed 1091 seconds by postgrey-1.37 at boromir; Sat, 29 Aug 2026 16:44:00 AEST Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4hX5M42Sytz2xT6 for ; Sat, 29 Aug 2026 16:43:57 +1000 (AEST) dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=TJPANoRDN+fYMKpdt+JU9S3bLccMRqCiof0MgFwWlzU=; b=e1y7l4PhB4SfaOvwKAgMRqpDb/LHbrOvtd4RRG+s06Bp4xSgq0ZtZIK38odls8nOMy+Pssfhs dIjbctOBeEbXuDyPgy+AkY4UfTzbYxhEcpy+gjZcQ9qv73489a4eDbvWgIWcyRat6z/ITUyOQq+ TAfgjFIDi2aRqlLcXMYK00s= Received: from canpmsgout05.his.huawei.com (unknown [172.19.92.145]) by szxga01-in.huawei.com (SkyGuard) with ESMTPS id 4hX4xM4HYVz1BFqN for ; Sat, 29 Aug 2026 14:25:11 +0800 (CST) dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=TJPANoRDN+fYMKpdt+JU9S3bLccMRqCiof0MgFwWlzU=; b=e1y7l4PhB4SfaOvwKAgMRqpDb/LHbrOvtd4RRG+s06Bp4xSgq0ZtZIK38odls8nOMy+Pssfhs dIjbctOBeEbXuDyPgy+AkY4UfTzbYxhEcpy+gjZcQ9qv73489a4eDbvWgIWcyRat6z/ITUyOQq+ TAfgjFIDi2aRqlLcXMYK00s= Received: from mail.maildlp.com (unknown [172.19.162.197]) by canpmsgout05.his.huawei.com (SkyGuard) with ESMTPS id 4hX4jz5zbRz12LDl; Sat, 29 Aug 2026 14:15:19 +0800 (CST) Received: from dggpemr100018.china.huawei.com (unknown [7.185.36.64]) by mail.maildlp.com (Postfix) with ESMTPS id 483714057D; Sat, 29 Aug 2026 14:25:35 +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; Sat, 29 Aug 2026 14:25:34 +0800 From: zhouminqiang To: , , , , , CC: , , , , , , Subject: [PATCH v2 7/7] jffs2: add runtime toggle for write verification Date: Sat, 29 Aug 2026 14:16:57 +0800 Message-ID: <20260829061658.306854-8-zhouminqiang2@huawei.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260829061658.306854-1-zhouminqiang2@huawei.com> References: <20260829061658.306854-1-zhouminqiang2@huawei.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.50.85.155] X-ClientProxiedBy: kwepems100001.china.huawei.com (7.221.188.238) To dggpemr100018.china.huawei.com (7.185.36.64) 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 75b4244e93b8..913183329c54 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); if (!verify_buf) { pr_warn("%s(): verify buffer allocation failed, skipping verification\n", -- 2.52.0