----- Ursprüngliche Mail ----- >> But let me advertise ubiblock a second time. > Sorry, I could not understand about the ubiblock request. Is it > possible to elaborate little more ? > We are already using squashfs on top of our UBI volumes (including > rootfs mounting). > This is the kernel command line we pass: > rootfstype=squashfs root=/dev/mtdblock44 ubi.mtd=40,0,30 > And CONFIG_MTD_UBI_BLOCK=y is already enabled in our kernel. > Do we need to do something different for ubiblock ? >From that command line I understand that you are *not* using squashfs on top of UBI. You use mtdblock. ubiblock is a mechanism to turn an UBI volume into a read-only block device. See: http://www.linux-mtd.infradead.org/doc/ubi.html#L_ubiblock >> If you place your squashfs on a UBI static volume, UBI knows the exact length >> and you can checksum it >> more easily. > Yes, we use squashfs on UBI volumes, but our volume type is still dynamic. > Also, you said, UBI knows the exact length, you mean the whole image length ? > How can we get this length at runtime ? You need a static volume for that. If you update a static volume the length is known by UBI. > Also, how can we get the checksum of the entire UBI volume content > (ignoring the erased/empty/bad block content) ? Just read from the volume. /dev/ubiX_Y. > Or, you mean to say, the whole checksum logic is in-built inside the > UBI layer and users don't need to worry about the integrity at all ? Static volumes have a crc32 checksum over the whole content. Of course this offers no cryptographic integrity. See: http://www.linux-mtd.infradead.org/doc/ubi.html#L_overview Thanks, //richard
