Charlotte Koch <[email protected]> writes: > # mount -t null /src /dest > # mount -t null /src /dest > # mount -t null /src /dest > ... > > You can umount /dest multiple times, too, and it just works. That's > pretty neat; I suppose the "stackable layer" design of the file system > doesn't prevent this sort of interaction from happening. But to me, it > still feels wrong to permit a mount with the *same* source and the > *same* destination multiple times. > > Does it make sense to prevent the user from creating a null mount whose > parameters match an existing null mount?
I don't think it really does. In general, you can mount things to any dir, whether or not it is previously mounted. If you disallow a full match, why don't you disallow mount -t null /src1 /dest mount -t null /src2 /dest If that's ok, what about mount -t null /src1 /dest mount -t null /src2 /dest mount -t null /src1 /dest If someon has a scheme that mounts multiple things and unwinds the stack, why should they get an error if two things match?
