lkml.org 
[lkml]   [2006]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [BUG?] possible recursive locking detected
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.

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

\
 
 \ /
  Last update: 2006-07-27 09:27    [W:0.051 / U:0.412 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site