Re: [patch] fs: new inode i_state corruption fix

From: Jan Kara
Date: Thu Mar 05 2009 - 06:12:45 EST


On Thu 05-03-09 11:16:37, Nick Piggin wrote:
> On Thu, Mar 05, 2009 at 11:00:01AM +0100, Jan Kara wrote:
> > On Thu 05-03-09 07:45:54, Nick Piggin wrote:
> > > after ~1hour of running. Previously, the new warnings would start immediately
> > > and hang would happen in under 5 minutes.
> > A quick grep seems to indicate that you've still missed a few cases,
> > haven't you? I still see the same problem in
> > drop_caches.c:drop_pagecache_sb() scanning, inode.c:invalidate_inodes()
> > scanning, and dquot.c:add_dquot_ref() scanning.
> > Otherwise the patch looks fine.
>
> I thought they should be OK; drop_pagecache_sb doesn't play with flags,
> invalidate_inodes won't if refcount is elevated, and I think add_dquot_ref
> won't if writecount is not elevated...
Ah, ok, you are probably right.

> But maybe that's abit fragile and it would be better policy to always
> skip I_NEW in these traverals?
Yes, it seems too fragile to me. I'm not saying we have to forbid
everything for I_NEW inodes but I think we should set clear simple rules
what is protected by I_NEW and then verify that all sites which can come
across such inodes obey them.

Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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