On Wed, 11.01.12 16:04, Jan Engelhardt (jeng...@medozas.de) wrote: > Now, Kay Sievers claims (on IRC) pivot_root is "10 years ago stuff" and > points to util-linux's switchroot function for how things are supposedly > to be done today. But, as we look at > http://git.kernel.org/?p=utils/util-linux/util-linux.git;a=blob;f=sys-utils/switch_root.c;hb=HEAD#l150 > > what can really be seen there is that the new root (/dev/sda3 in my > previous commands example) is just mounted atop the rootfs-type > vfsmount, thereby concealing it. > (That is not a replacement for what pivot_root does, really.) > > Of course, if you conceal the rootfs-type vfsmount, there is no way that > the proc trick is going to work -- which is why I proposed using > pivot_root instead of {MS_MOVE + chroot} and *keeping* the rootfs > vfsmount around, in a visible fashion.
The chroot() call in switch_root is just to drop the reference to the old mount point, it doesn't really have a lot of meaning besides that. It's like the chdir() call there too, which drops another reference to the old mount. pivot_root is very similar to an MS_BIND for the old root dir plus an MS_MOVE for the new one, and as such is pretty much obsolete. Lennart -- Lennart Poettering - Red Hat, Inc. _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
