why UBI static volumes are flagged as DEVFS_IS_CHARACTER_DEV

iw3gtf at arcor.de iw3gtf at arcor.de
Wed Oct 5 06:23:15 PDT 2016


I noticed that the commit id c087e0804f0290e9886899e8a3cccb07c4ce088b flagged static

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) ?


Giorgio, iw3gtf at arcor.de

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