From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Tue, 08 Feb 2022 09:24:09 +0100 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nHLnF-009Az5-CQ for lore@lore.pengutronix.de; Tue, 08 Feb 2022 09:24:09 +0100 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nHLnD-00086q-6e for lore@pengutronix.de; Tue, 08 Feb 2022 09:24:08 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:From:In-Reply-To:MIME-Version: References:Message-ID:Subject:Cc:To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=8BmZyV4YsJsiOixXRdEJgxhWfZ0okkaIdD0SW6gMKnA=; b=tpLIhbJCt61p2LlSANrDfpW35j dmXcDb+BUuwPJgxXak8Ek/egUOy3+ZnmlUX4ADPuZryPtlo/P9uufPpwyoYMidZQmWfrnuK4gdU6B /m85eDL3CBcLnbJM8bqhX9bRg+GioX6q7hsGk7hbico1B/Doh4QIMm58FT4YHHlXLBdvcQnqYxcvh A+9DHwF2+VKHkH5EBCcY5WxrnMja9/qjJHpCicT+N9QYrCow6BaGU2D/J0Dz6tScIuJqnQ/hUYwjK g0fR+qGfrFsxGFWlHn6l2loBJoDuUTlUAoaUaUv+sqM85mOb393GqQnbrZ4+4KXT3XHadUhf4IRVd V5R4NT3Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHLlm-00CvN1-EP; Tue, 08 Feb 2022 08:22:38 +0000 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHLix-00Cu0K-0c for barebox@lists.infradead.org; Tue, 08 Feb 2022 08:19:56 +0000 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nHLiv-00079w-Oz; Tue, 08 Feb 2022 09:19:41 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1nHLiv-0003yd-Ff; Tue, 08 Feb 2022 09:19:41 +0100 Date: Tue, 8 Feb 2022 09:19:41 +0100 To: Holger Assmann Cc: barebox@lists.infradead.org, Ahmad Fatoum Message-ID: <20220208081941.GN18637@pengutronix.de> References: <20220207173239.772421-1-h.assmann@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220207173239.772421-1-h.assmann@pengutronix.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 09:19:31 up 59 days, 17:05, 81 users, load average: 0.23, 0.18, 0.18 User-Agent: Mutt/1.10.1 (2018-07-13) From: Sascha Hauer X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220208_001943_089310_39B1C01D X-CRM114-Status: GOOD ( 34.60 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:e::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.ext.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-4.6 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH v3] fs: jffs2: fix error when reading blocks with offset X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.ext.pengutronix.de) On Mon, Feb 07, 2022 at 06:32:39PM +0100, Holger Assmann wrote: > This bug resulted in a panic when trying to read a file partially with > an offset, e.g. when starting Linux. In such a case a header is loaded > by a separate call of jffs2_read(), which then copies only the first n > bytes out of the respective block. > When the remaining data of the block is then subsequently going to to be > read the system deviates in its behaviour from that under Linux by not > calling jffs2_read_inode_range() in a 4k-alignment, but with an offset. > > jffs2_read_inode_range() originates from the Linux jffs2 driver. When > being called with an offset it still reads 4096 bytes of data and > eventually returns fragments of two consecutive blocks. jffs2_read() > then reads this result whilst again applying the offset, therefore > returning faulty data. > > We fix that problem by calling jffs2_get_block() without an offset and > therefore reading the whole block. The offset is then applied when we > actually perform memcpy with the returned buffer. This fix might also > increase the performance since the respective block is likely to be > cached from the previous call. > > Signed-off-by: Holger Assmann > Reviewed-by: Ahmad Fatoum > --- Applied, thanks Sascha > > Changes v1 -> v2: > - removed stray spaces > - added review acknowledgement > Changes v2 -> v3: > - use actual "JFFS2_BLOCK_SIZE" instead of "4096" > > fs/jffs2/fs.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c > index a267ec0669..0c57f1d07f 100644 > --- a/fs/jffs2/fs.c > +++ b/fs/jffs2/fs.c > @@ -74,6 +74,9 @@ static int jffs2_get_block(struct jffs2_file *jf, unsigned int pos) > struct jffs2_inode_info *f = JFFS2_INODE_INFO(jf->inode); > int ret; > > + /* pos always has to be 4096 bytes aligned here */ > + WARN_ON(pos % JFFS2_BLOCK_SIZE != 0); > + > if (pos != jf->offset) { > ret = jffs2_read_inode_range(c, f, jf->buf, pos, > JFFS2_BLOCK_SIZE); > @@ -98,12 +101,13 @@ static int jffs2_read(struct device_d *_dev, FILE *f, void *buf, > /* Read till end of current block */ > ofs = f->pos % JFFS2_BLOCK_SIZE; > if (ofs) { > - ret = jffs2_get_block(jf, pos); > + ret = jffs2_get_block(jf, f->pos - ofs); /* Align down block */ > if (ret) > return ret; > > now = min(size, JFFS2_BLOCK_SIZE - ofs); > > + /* Complete block has been read, re-apply ofset now */ > memcpy(buf, jf->buf + ofs, now); > size -= now; > pos += now; > -- > 2.30.2 > > > _______________________________________________ > barebox mailing list > barebox@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/barebox > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox