Andy Lutomirski <luto@xxxxxxxxxxxxxx> writes: > On 08/14/2013 10:42 AM, Miklos Szeredi wrote: >> There's a simple and effective way to prevent unlink(2) and rename(2) >> from operating on any file or directory by simply mounting something >> on it. In any mount instance in any namespace. >> >> Was this considered in the unprivileged mount design? >> >> The solution is also theoretically simple: mounts in unpriv namespaces >> are marked "volatile" and are dissolved on an unlink type operation. > > I'd actually prefer the reverse: unprivileged mounts don't prevent > unlink and rename. If the dentry goes away, then the mount could still > exist, sans underlying file. (This is already supported on network > filesystems.) Of course we do this in network filesystems by pretending the rename/unlink did not actually happen. The vfs insists that it be lied to instead of mirroring what actually happened. Again all of this is a question about efficient data structures and not really one of semantics. Can either semantic be implemented in such a way that it does not slow down the vfs? Eric -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
