Re: [RFC, PATCH 6/6] ext3: do not write to the disk when mounting a dirty read-only filesystem

Duane Griffin
2008-03-06T11:19:06Z

On 06/03/2008, Andreas Dilger <adilger@sun.com> wrote:
> On Mar 06, 2008 01:59 +0000, Duane Griffin wrote:
> > NOTE: For now I'm simply preventing filesystems requiring recovery from being
> > remounted read-write. This breaks booting with an uncleanly mounted root
> > filesystem!
>
> I was going to ask about this - not being able to remount rw is a serious
> problem because many users have only the root filesystem and this
> limitation basically prevents this patch from being landable.

Yep, I agree. I wanted to post this as an RFC now to get feedback on
the overall approach. I'll try and get remount support in there ASAP
and post another version.

> I'd suggest if the filesystem is going to be remounted read/write that
> the journal mapping be discarded and the journal replayed. Depending
> on how you do the mapping it may be necessary to invalidate all of the
> pages in the cache so that they don't reference the blocks in the journal.

That was along the lines I was thinking of, too. Thanks for mentioning
invalidating the page cache -- I'll make sure that doesn't get
overlooked.

> Cheers, Andreas

Cheers,
Duane.

--
"I never could learn to drink that blood and call it wine" - Bob Dylan