On 25 Oct 2012, nix@xxxxxxxxxxxxx said: > Even though my own system relies on the possibility of rebooting during > umount to reboot reliably, I'd be inclined to say 'not a bug, don't do > that then' -- except that this renders it unreliable to use umount -l to > unmount all the filesystems you can, skipping those that are not > reachable due to having unresponsive servers in the way. It's worse than that. If you're using filesystem namespaces, how can *any* shell script loop, or anything in userspace, reliably unmount all filesystems before reboot? It seems to me this is impossible. There is no process that necessarily has access to all namespaces, and when you bring PID namespaces into the picture there is no process that can even kill all userspace processes in order to zap their filesystems. I suspect we need a new blocking 'umountall' syscall and a command that calls it, which umounts everything it can in every filesystem namespace it can, skipping those that are (unreachable?) network mounts, and returns only when everything is done. (Possibly it should first kill every process it sees in every PID namespace other than that of the caller, too.) Then shutdown scripts can just call this, and get the right behaviour immediately. -- NULL && (void) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
