Messages in this thread |  | | | Date | Wed, 26 Jan 2000 01:16:02 +0100 | | From | Guest section DW <> | | Subject | Re: [PATCH] root-hopping for pre-2.3.41-3 |
| |
On Tue, Jan 25, 2000 H. Peter Anvin wrote:
------------------------------------------------------------------ pivot_root("new_root", "old_root"); This will detach the path "new_root" and turn it into the new root, and *then* attach the *old* root, now detached, to the path "old_root", which must be a valid mount point (i.e. directory) in the new root. ------------------------------------------------------------------ Excellent!
[But let us be careful. Mounting a filesystem is taking a path /path and letting it be an alias for the root directory of the filesystem. Some Unix flavours allow overmounting, where more than one filesystem is mounted on the same path - maybe Linux doesnt allow that today, it didnt last time I checked, but still I suppose it would be good to define the semantics of pivot_root() in such a case.]
Werner added:
> > > ... with an implicit "chroot everybody on / to /new_root". That would > > > solve a few problems, yes. I'll give it a try.
and Peter answered
> > Right... everyone on the old / move to the new /, although I guess > > that's technically not 100% necessary.
but I wonder. Usually in such a situation not many processes will be around, but still.. It would be strange if the interpretation of paths suddenly changed for processes other than the one doing this pivot_root. So, I would prefer these old processes all to remain where they are, with the same root inode (that just got a new name, namely /old_root).
Thus, the only process that would get the new / as root would be the process doing this pivot_root() (and perhaps init?).
Andries
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
|  |