>>>>> "john" == John Tyner <jtyner@cs.ucr.edu> writes: Hi john> I'm working on a pet project in my spare time in which the root device is john> not known at kernel compile time. So, I load the ramdisk and linuxrc does john> the work of finding the root device and mounting it and so on. When my john> linuxrc exits; however, the code above tries to mount what it thinks john> should be the root device (and usually panics). Am I doing something wrong john> here? john> Second, the inner if doesn't seem necessary to me. Since the outer if john> determines that ROOT_DEV is a ramdisk and that real_root_dev is not the john> same as ROOT_DEV, the inner if will always succeed. Read mkinitrd from RH or Mandrake (I think that others also use it, but I don't know), and you will see that they do the change_root (calling pivot_root()) themselves, for instance that is what a Mandrake initrd does (RH does basically the same module devfs issues). <load misc modules here> echo Mounting /proc filesystem mount -t proc /proc /proc echo Creating root device mkrootdev /dev/root echo 0x0100 > /proc/sys/kernel/real-root-dev umount /proc echo Mounting root filesystem mount --ro -t ext3 /dev/root /sysroot pivot_root /sysroot /sysroot/initrd echo Remounting devfs at correct place if necessary handledevfs Notice the mkrootdev call, it clereates /dev/root in real_root_dev, you change the value of real_root_dev that you see in the previous code to the value that you want, then mount the root filesystem. Notice that here, the system get a lot of trouble to be sure that / is mounted from /dev/root, you possible don't need that, the important part is the real_root_dev and the pivot_root calls. This is nasm shell script, you can download it from the mkinitrd, it only have a couple of commands (you can see almost all that it can do in that script). Yes, linux boot sequence is a mesh, but it appears that in 2.5 it will be much nicer. Hope this helps. Later, Juan. -- In theory, practice and theory are the same, but in practice they are different -- Larry McVoy -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/
