Messages in this thread | | | Date | Thu, 27 Jul 2006 00:24:32 -0700 | From | Andrew Morton <> | Subject | Re: [BUG?] possible recursive locking detected |
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On Thu, 27 Jul 2006 16:51:29 +1000 Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > We hold the ext2 directory mutex, and ntfs_put_inode is trying to take an > > ntfs i_mutex. Not a deadlock as such, but it could become one in ntfs if > > ntfs ever does a __GFP_WAIT allocation inside i_mutex, which it surely > > does. > > Though it should be using GFP_NOFS, right? So the dcache shrinker would > not reenter the fs in that case.
Sort-of, arguably. Many years ago, holding i_mutex (i_sem) was considered to be "in the fs" and one should use GFP_NOFS.
(This code dates from the ext2 directory-in-pagecache conversion - it's 2.4 stuff.)
It's better, of course, to use GFP_HIGHUSER for pagecache so we should aim to get this working. And that means don't-take-i_mutex-on-the-reclaim-path.
We quite possibly are doing that in other places, too.
> I'm surprised ext2 is allocating with __GFP_FS set, though. Would that > cause any problem?
It might, if ext2 takes i_mutex on the reclaim path. But it doesn't.
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