Red Hat Bugzilla – Bug 484190
mount: tmpfs to reject mounts of the same mountpoint
Last modified: 2009-02-05 07:18:24 EST
Description of problem: mount should reject attempts to mount already mounted filesystem. Example: [root@dorado_v1 /]# mount dorado:/exports/ext1/tmp /tmp2 [root@dorado_v1 /]# mount dorado:/exports/ext1/tmp /tmp2 mount.nfs: /tmp2 is already mounted or busy -- correct behavior. However if I try the same using tmpfs, it does not reject it: [root@dorado_v1 /]# mount -t tmpfs none /tmp2 [root@dorado_v1 /]# mount -t tmpfs none /tmp2 So /tmp2 is mounted twice now. This should not be possible. Version-Release number of selected component (if applicable): All versions of Fedora and RHEL are affected by this bug. How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: /tmp2 is mounted twice using tmpfs Expected results: Once /tmp2 is mounted, any consequential mounts to this mountpoint should be refused (as it already work for NFS, for example). Additional info:
That's correct. You cannot mount the same filesystem on the same mountpoint more than once (e.g your NFS), BUT linux supports overlaying -- it means you can mount more (different) filesystems on the same mountpoint, e.g: mount /dev/foo /mnt mount /dev/bar /mnt and you can also mount the same device on more places, e.g: mount /dev/foo /mnt mount /dev/foo /mnt2 Note that the "tmpfs" is always unique filesystem.