Another question on bind mounts without mtab

Another question on bind mounts without mtab

[Phillip Susi]

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I've had another question come up about bind mounts and the lack of
mtab and I'm not sure how to answer it because it does seem a more
important use case that has been lost than those previously discussed.

If /dev/sda1 is mounted in /, and you bind mount /home/foo to /mnt,
then there is no way to tell from the output of mount that it is in
fact, the /home/foo directory of /dev/sda1 that is in /mnt.  It looks
like you just bind mounted the whole drive there, and the subdirectory
path is lost.

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Re: Another question on bind mounts without mtab

[Karel Zak]

On Fri, Jan 10, 2014 at 09:38:20AM -0500, Phillip Susi wrote:
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> Hash: SHA1
> 
> I've had another question come up about bind mounts and the lack of
> mtab and I'm not sure how to answer it because it does seem a more
> important use case that has been lost than those previously discussed.
> 
> If /dev/sda1 is mounted in /, and you bind mount /home/foo to /mnt,
> then there is no way to tell from the output of mount that it is in
> fact, the /home/foo directory of /dev/sda1 that is in /mnt.  It looks
> like you just bind mounted the whole drive there, and the subdirectory
> path is lost.

 See findmnt output, the /proc/self/mountinfo contains info about the
 mounted filesystem directory (usually '/', but /home/foo in your
 example).

 Note that I'd like to learn people to use findmnt(8) rather mount
 output. The mount(8) output is there mostly for backward
 compatibility.

    Karel


-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com