Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1495462

Re: Regression in next with ext4 oops

Show all headers | View raw

On Tue, Oct 04, 2016 at 10:02:31AM -0400, Theodore Ts'o wrote:
> 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.

Jan is wrong - we do have per-struct-file serialization for getdents()
et.al.  It might be a race between getdents() on *different* struct
file for the same directory, but ->private_data is not a problem.

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 01:40 +0200
  Re: Regression in next with ext4 oops Jan Kara <jack@suse.cz> - 2016-10-04 11:10 +0200
    Re: Regression in next with ext4 oops Theodore Ts'o <tytso@mit.edu> - 2016-10-04 16:10 +0200
      Re: Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 16:50 +0200
      Re: Regression in next with ext4 oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-04 17:00 +0200
        Re: Regression in next with ext4 oops Theodore Ts'o <tytso@mit.edu> - 2016-10-04 21:10 +0200
          Re: Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 21:20 +0200
        Re: Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 21:20 +0200
          Re: Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 21:30 +0200
            Re: Regression in next with ext4 oops Kalle Valo <kvalo@codeaurora.org> - 2016-10-04 21:50 +0200
              Re: Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 22:40 +0200
                Re: Regression in next with ext4 oops Kalle Valo <kvalo@codeaurora.org> - 2016-10-05 12:00 +0200
    Re: Regression in next with ext4 oops Tony Lindgren <tony@atomide.com> - 2016-10-04 16:20 +0200
    Re: Regression in next with ext4 oops Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-04 17:00 +0200
      Re: Regression in next with ext4 oops Jan Kara <jack@suse.cz> - 2016-10-05 07:50 +0200

csiph-web