(unknown)

[JB]

JB <jb.1234abcd <at> gmail.com> writes:

> ... 
> While having that /dev/sda10 (FreeBSD slice) mounted as above, I used cfdisk
> and added /dev/sda10 Linux partition (right after /dev/sda9 of course).
> 
> To my surprise, I discovered that after that df and mount do not show that
> FreeBSD /dev/sda10 mounted partition ! Magically disappeared 

Sorry, not exactly.
The cfdisk action did not cause it of course; it ends with a write command (it
is suggested to reboot to make the changes permanent).
But until that time it creates a presumably semi-permanent state of /dev/sda10
being in cfdisk and fdisk displays, and at the same time df and mount showing
/dev/sda10 mounted as UFS partition on /media mount point.
A subsequent reboot cleared that temporary manual /media mount.

> ... 
> What would have happened (as I suggested it previously) if I put that FreeBSD
> /dev/sda10 in /etc/fstab ?
> That new Linux /dev/sda10 partition would be auto mounted at that mount point,
> which would presumably be a source of data for some system or user app ...

That test was done by me.
# cat /etc/fstab
...
/dev/sda10              /media                  ufs     ro,ufstype=ufs2  0 0
...

In this case /dev/sda10 was already a Linux parition per above and the mount
failed as shown in boot log:
# dmesg
...
[   18.597349] EXT4-fs (sda7): re-mounted. Opts: (null)
[   18.835869] ufs_read_super: bad magic number
[   20.743108] Adding 2933244k swap on /dev/sda5.  Priority:-1 extents:1
across:2933244k 
...

But other bad outcomes are possible (see next post).

> ... 

JB