> In other words the "rename("/mnt", "/mnt/foo")" should have failed with EINVAL, not EXDEV
I thought about that one, too. But I guess there is 2 kinds of subdirectory-of: In the mount hierarchy possibly across devices, and on a single device in terms of inode-reachability.
Absence of the first condition does not preclude the second condition: Many filesystems can be mounted at multiple places.
I think the point of EINVAL is to prevent screwing up the intra-device inode links. For this case, the check can't be made in the mount hierarchy. So it seems natural to me that the EXDEV check comes first.
I thought about that one, too. But I guess there is 2 kinds of subdirectory-of: In the mount hierarchy possibly across devices, and on a single device in terms of inode-reachability.
Absence of the first condition does not preclude the second condition: Many filesystems can be mounted at multiple places.
I think the point of EINVAL is to prevent screwing up the intra-device inode links. For this case, the check can't be made in the mount hierarchy. So it seems natural to me that the EXDEV check comes first.