From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.phycard.de ([217.6.246.34] helo=root.phytec.de) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1btVmy-0001XK-H5 for barebox@lists.infradead.org; Mon, 10 Oct 2016 08:18:25 +0000 Message-ID: <1476087474.4195.7.camel@lws-tremmet.phytec.de> From: Teresa Remmet Date: Mon, 10 Oct 2016 10:17:54 +0200 In-Reply-To: <20161007072720.u3c7k6qv4pphlihz@pengutronix.de> References: <1382352141.1327180.1475673795806.JavaMail.ngmail@webmail09.arcor-online.net> <1475741847.3468.20.camel@lws-tremmet.phytec.de> <20161007072720.u3c7k6qv4pphlihz@pengutronix.de> Mime-Version: 1.0 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" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: why UBI static volumes are flagged as DEVFS_IS_CHARACTER_DEV To: Sascha Hauer Cc: barebox@lists.infradead.org, iw3gtf@arcor.de Hello Sascha, Am Freitag, den 07.10.2016, 09:27 +0200 schrieb Sascha Hauer: > On Thu, Oct 06, 2016 at 10:17:27AM +0200, Teresa Remmet wrote: > > Hello Giorgio, > > > > Am Mittwoch, den 05.10.2016, 15:23 +0200 schrieb iw3gtf@arcor.de: > > > Hi, > > > > > > I noticed that the commit id c087e0804f0290e9886899e8a3cccb07c4ce088b flagged static > > > UBI volumes as DEVFS_IS_CHARACTER_DEV. > > > > > > A consequence of this flag is that commands like: > > > > > > # cp /dev/nand0.ubi_volumes.ubi.my_static_vol file > > > > > > will not work because the cp command will see a src file (the static UBI volume) with a size > > > of -1 (FILE_SIZE_STREAM) and keep on reading from the volume until a flood of > > > "UBI assert failed in ubi_eba_read_leb at 359" asserts comes out of the console. > > > > > > I tried to comment out the flag assignment, just to see what happen: > > > > > > int ubi_volume_cdev_add(struct ubi_device *ubi, struct ubi_volume *vol) > > > { > > > ... > > > cdev->size = vol->used_bytes; > > > > > > // if (vol->vol_type == UBI_STATIC_VOLUME) > > > // cdev->flags = DEVFS_IS_CHARACTER_DEV; > > > > > > cdev->dev = &vol->dev; > > > ... > > > > > > and then the cp command worked than as expected. > > > > > > Could someone shortly confirm that the DEVFS_IS_CHARACTER_DEV flag for static UBI volumes > > > is really needed (to avoid some other problems that my superficial test does not triggers) ? > > > > the size of a static ubi volume device is equal to the image size you > > flashed. When you create a new static ubi volume the size is 0, as it is > > empty. > > We need the chardev flag to be able to update the static ubi volume or > > barebox will complain that there is not enough space. > > Then I think we need another solution for that. UBI volumes are clearly > not character devices, so we shouldn't set this flag to work around > other issues we have. Yes, you are write using the character dev flag is more a work around. Which now brings up other problems like dumping the data back from flash. > > Currently devfs_truncate is implemented like: > > static int devfs_truncate(struct device_d *dev, FILE *f, ulong size) > { > if (f->fsdev->dev.num_resources < 1) > return -ENOSPC; > if (size > resource_size(&f->fsdev->dev.resource[0])) > return -ENOSPC; > return 0; > } > > Maybe we need an optional cdev->ops->truncate() to let the UBI volumes be > able to overwrite this behaviour? Truncate sounds like a better way. But UBI itself is not a filesystem. So I do not see a good place to overwrite it on a first look. I will try to look into this deeper next week. Regards, Teresa > > Sascha > _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox