Re: Regression in next with ext4 oops
From: Tony Lindgren
Date: Tue Oct 04 2016 - 10:44:50 EST
* Theodore Ts'o <tytso@xxxxxxx> [161004 07:04]:
> On Tue, Oct 04, 2016 at 11:00:41AM +0200, Jan Kara wrote:
> > Never seen this but I suspect it is a fallout from Al's directory locking
> > changes. In particular ext4_htree_fill_tree() builds rb-tree of found
> > directory entries in file->private_data (and generally modifies the
> > structure stored there) but after Al's changes we don't have exclusive
> > access to struct file if I'm right so if two processes end up calling
> > getdents() for the same 'struct file' we are doomed.
> I haven't seen it either, and I've been doing a lot of testing on the
> ext4 test branch. So I'm guessing Tony has the only reliable repro
> for the problem at the moment. That being said, it shouldn't be that
> hard to create a test case for this and add it to xfstests.
> I'm pretty sure Jan is right about this, though, but it would be great
> to a get a quick confirmation from Tony if at all possible.
Looks like Jan's patch somehow makes things worse for me.