On 5/2/09, Kay Sievers <kay.sievers@xxxxxxxx> wrote: > On Sat, May 2, 2009 at 22:22, Alan Jenkins > <sourcejedi.lkml@xxxxxxxxxxxxxx> wrote: > >> On a narrow issue: do you really object to moving the "mount dev -t >> devfs2 /dev" into userspace (and therefore giving it a user-visible >> name)?? That would address Cristophs particular objection about >> "messing around" with the initial namespace. > > An argument which does not stand at all, there is no mess, it is not > mounted at all until we are ready with initializing the kernel. And > instead of creating some random nodes in /dev like we do today, we > mount it, and it contains a node for every device. I hardly see any of > the mentioned "namespace mess" here, it's just the simplest, most > robust, and most efficient thing we can do. :) > >> It means I can be 100% >> sure I can boot an old initramfs with this option enabled. > > Oh, it does not change anything for an existing initramfs, if that > option enabled. After initramfs found and mounted the real rootfs at > /root, your are totally free to call: > mount --move /dev/ /root/dev > or not to do that, like we do today. Sorry, you're right. I should go to bed :-). It would matter if you had a different naming scheme for /dev than the kernel, and you were trying to get away with a static /dev. I can't believe anyone important does that though :-). >> And it >> gives a nice clean way for new initramfs' to test for this feature - >> when they try to mount it, it fails. It would seem to make for a >> rather smoother migration path. > > I think that is all covered just fine. Oh, I see. grep "/dev" /proc/mounts > /dev/null > One thing that I tried to solve by doing a kernel mounted fs, is that > /dev on the rootfs is completely empty, it is that way on some distros > today, and if you do init=/bin/sh, it will not work, because > /dev/console is missing. > > Another thing, why I would like to avoid a new fstype is that > userspace checks if /dev is a tmpfs to find out if it's a dynamic /dev > - nothing really that should prevent us from doing a new filesystem, > but we should need a good reason to do it, I think. I thought udev was documented somewhere as compatible with a non-tmpfs /dev, in a "just because you could" sort of way. I've seen something test for tmpfs... nevermind, it's probably something different. (Just the init script that checks whether /dev has been mounted that way by an initramfs, or the user decided to do without intramfs' so the rootfs gets to mount it instead). Good night Alan -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
