Re: 2.6.0-test3-mm1 and rootflags

[Andrew Morton <akpm@osdl.org>]

Valdis.Kletnieks@vt.edu wrote:
>
> OK.. I'm stumped..
> 
> While testing something, I tried to boot with 'rootflags=noatime', and
> found the system wouldn't boot, as ext3, ext2, and reiserfs all failed to
> recognize the option.  Looking at the code in fs/ext3/super.c:parse_options()
> and init/do_mounts.c:root_data_setup(), it appears to be impossible
> to set any of the filesystem-independent flags via rootflags, which explains
> the special-case code for the 'ro' and 'rw' flags.  However, there doesn't
> seem to be any way to pass nodev, noatime, nodiratime, or any of the other
> flags.  (And yes, all 3 of those make sense in my environment - it's a laptop
> and I don't need atime, and I use devfs so nodev on the root makes sense too).
> 

The fs-independent options are parsed in user space by mount(8), and are
passed into the kernel as individual bits in a `flags' argument.

So we'd need a new `rootopts=0x0040' thingy to support this.  But given
that most things can be set after boot with `mount / -o remount,noatime',
it may not be necessary.