On Thu, Aug 15, 2013 at 8:45 AM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote: > Part of me does prefer the semantics Andy has suggested where instead of > unmounting things we have something like a skeleton of the mount tree > unioned with dcaches of the filesystems themselves. With "struct > mountpoint" we are amazing close to that already. > > A mount skeleton would allow us to always remove and rename directories > and files without really caring, about what mounts were present. > Probably with just a quick lookup to see if we need to set > DCACHE_MOUNTED. Yes, we could have a separate dentry tree just for anchoring mounts and we could make a union with the real dentry tree. But implementing that in a low overhead manner is not trivial. Anchoring mounts on real dentries is *rather* convenient. And yes, we only actually need the skeleton dentries when the real ones disappear, but that doesn't make the implementation any simpler. > The big practical problem I can see with MNT_VOLATILE is mount points in > shared directories like /tmp but without the sticky set. At which point > it would be possible to delete another users mount points. Perhaps we > need restrictions on where a user can mount. I think if user X mounts something on /tmp/foo owned by user Y and user Y removes /tmp/foo then that shouldn't really surprise user X. I don't see this an issue. Thanks, Miklos -- 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
