Re: mount: / mounted already or bad option

[Willy Tarreau <willy@w.ods.org>]

On Fri, Oct 10, 2003 at 06:35:37PM +0300, SMS WebMaster wrote:
> >>and when I login with the root and type
> >>mount -o remount,rw /
> >>
> >>I got the same message
> >>mount: / mounted already or bad option
> >>
> >>but if I write
> >>mount -o remount,rw /dev/hda4  /
> >>then the root filesystem if remounted as read/write
> >
> >
> >wouldn't your /etc/mtab be a link to /proc/self/mounts with /proc not 
> >mounted ?
> 
> 
> Sorry what do you mean ?

I meant that when you use the "incomplete" syntax with mount (ie: no device
specified), it relies on /etc/mtab to find the mount entry you want to change.
And it's somewhat common to have /etc/mtab be a symlink to /proc/self/mounts
when you don't want /etc to be written to, because the 'mounts' entry has
nearly the same format as 'mtab' (a few missing options). Now if it was the
case, and /proc was not mounted yet, /etc/mtab would point to nowhere and mount
would have no way to find what was mounted on '/', which could lead to some
errors like this.

> if I type mount I can see that proc is mounted (I can even see / is 
> mounted as read/write but its not realy mounted as read/write)

OK, so it doesn't come from this. Perhaps your /etc/mtab is simply broken by
some random mount option somewhere ? Also, do you use the "read-only" option
on the kernel command line ? And do your init scripts clear /etc/mtab at boot,
before the first mounts ?

Willy