From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Fri, 03 Dec 2021 07:39:00 +0100 Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by lore.white.stw.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1mt2Dk-0001pn-88 for lore@lore.pengutronix.de; Fri, 03 Dec 2021 07:39:00 +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 1mt2Dj-0000yd-AU for lore@pengutronix.de; Fri, 03 Dec 2021 07:39:00 +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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=a1mB84DqkCcUJUhTtMBG7CVwtReUk/wfchYfnWifGIc=; b=IUuDi+PIofzBKM GdFGvn/8tEWC9kppDARL9XAy2ng/GgavF9h3WGXUbk2Bepi57s3zqvqdXKHBol9wMceZcdOXO0a4k YHlqoKnR3zRMJNBJ7BB9prRxktf+DWBZrTBk09fHWhRny7JPWgylww2uhLBvYkhbSFDcKAyHlF0o1 tHb2dCCxnF+yCP5rgY3RLmpr2YpNWZY3yRMqK6P4DDTGUOuqUmany22V54oRwtCceZ6d10SgizgYD eWkoog3xtno6l3CO1dpvopICNZR5aYOoGucCoeIdvVObaJJDV4idbzDYffLMYuA3jWc5fC3Yads7R +AdHG1j56/DKBNxUxl1Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mt2CU-00EXYV-Pf; Fri, 03 Dec 2021 06:37:42 +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 1mt2CP-00EXXd-F6 for barebox@lists.infradead.org; Fri, 03 Dec 2021 06:37:39 +0000 Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[127.0.0.1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1mt2CN-0000ti-3P; Fri, 03 Dec 2021 07:37:35 +0100 To: Holger Assmann , barebox@lists.infradead.org References: <20211202104837.3912925-1-h.assmann@pengutronix.de> From: Ahmad Fatoum Message-ID: Date: Fri, 3 Dec 2021 07:37:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <20211202104837.3912925-1-h.assmann@pengutronix.de> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211202_223737_541468_D58F48E7 X-CRM114-Status: GOOD ( 29.74 ) 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: , Cc: afa@pengutronix.de 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=-6.6 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: Re: [PATCH] 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 02.12.21 11:48, 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 > --- > fs/jffs2/fs.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c > index 1a2b443792..3d4cb98c97 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 % 4096 != 0); > + > if (pos != jf->offset) { > ret = jffs2_read_inode_range(c, f, jf->buf, pos, > JFFS2_BLOCK_SIZE); > @@ -98,13 +101,14 @@ 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); > > - memcpy(buf, jf->buf + ofs, now); > + /* Complete block has been read, re-apply ofset now */ > + memcpy(buf, jf->buf + ofs, now); Newly added stray space at end of line. Apart from that: Reviewed-by: Ahmad Fatoum > size -= now; > pos += now; > buf += now; > -- 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