We have a /foo/bar_new FS on a CentOS 7.
We have an old /foo/bar FS on a HW raid.
We copied all the data to the /foo/bar_new FS, from the /foo/bar old FS.
We umounted /foo/bar (the old disk that is/was on HW RAID), removed it from fstab.
We updated the fstab with /foo/bar_new to /foo/bar (it is on another disk, this is the new FS, but it needs to be reachable via the old filesystems path).
We mounted the /foo/bar (but this is the new FS now on new disks).
We removed the HW raid with: "storcli /c0/v4 del force".
And here comes the fun part:
/foo/bar (the new FS with this old mountpoint) got umounted automatically!
We cannot mount the /foo/bar anymore (it should be the new FS, just changed the mount point in fstab from /foo/bar_new to /foo/bar).
We can only mount the new FS to /foo/bar_new, but not /foo/bar.
When we try to mount the new fs to the old fs path, mount command says it mounted the FS to /foo/bar, but in reality it didn't.