Re: Hibernation considerations

[david]

On Sun, 15 Jul 2007, Alan Stern wrote:

> On Sun, 15 Jul 2007 david@xxxxxxx wrote:
>
> > > (1) Filesystems mounted before the hibernation are untouchable
> > >
> > >    When there's a memory snapshot, either in the form of a hibernation image,
> > >    or in the form of the "old" kernel and processes available to the "new"
> > >    kexeced kernel responsible for saving their memory, the filesystems mounted
> > >    before the hibernation should not be accessed, even for reading, because
> > >    that would cause their on-disk state to be inconsistent with the snapshot
> > >    and might lead to a filesystem corruption.
> >
> > AFAIK this is only the case with ext3, all other filesystems could be
> > accessed read-only safely
> >
> > this is arguably a bug with ext3 (and has been discussed as such), but
> > right now the ext3 team has decided not to change this bahavior so
> > hibernate needs to work around it. but don't mistake a work-around for a
> > single (admittedly very popular) filesystem with a hard and fast
> > directive.
>
> Isn't is possible to avoid this problem by mounting an ext3 filesystem
> as readonly ext2?  Provided the filesystem isn't dirty it should be
> doable.  (And provided the filesystem doesn't use any ext3 extensions
> that are incompatible with ext2.)

from the last discussion I saw on the kernel mailing list, no. the act of 
mounting the ext3 filesystem as ext2 read-only will change it as the 
unsupported extentions get turned off (and I think the journal contents at 
least are lost as part of this)

David Lang
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/