Re: Adding subroot information to /proc/mounts, or obtaining that through other means

H. Peter Anvin
2007-06-20T22:08:19Z

Karel Zak wrote:
> On Wed, Jun 20, 2007 at 01:57:33PM -0700, H. Peter Anvin wrote:
>> We could add a field to /proc/mounts to add this information:
>>
>> /dev/md6 /export ext3 rw,data=ordered 0 0 /
>> /dev/md6 /home/foo ext3 rw,data=ordered 0 0 /users/foo
>> /dev/md6 /home/bar ext3 rw,data=ordered 0 0 /users/bar
>
> I prefer this format. It's compatible with the mount(8) -- the mount
> ignores extra columns.
>
>> ... or, alternatively, add a subfield to the first field (which would
>> entail escaping whatever separator we choose):
>>
>> /dev/md6 /export ext3 rw,data=ordered 0 0
>> /dev/md6:/users/foo /home/foo ext3 rw,data=ordered 0 0
>> /dev/md6:/users/bar /home/bar ext3 rw,data=ordered 0 0
>
> We needn't a new separator (':') there already is one (' ').
>
>> I'm personally leaning toward the second option (/dev/md6:/users/foo).
>> Although that might confuse current utilities, those utilities are
>> *already* liable to get confused by the fact that the line doesn't mean
>> what they think it means.
>
> Many people use "ln -s /proc/mounts /etc/mtab".
>

Out of curiosity, and trying to better grok the problem, what would
mount(8) do differently with the second format versus the first?

-hpa