Re: regression: 100% io-wait with 2.6.24-rcX

Fengguang Wu
2008-01-14T03:54:39Z

On Sun, Jan 13, 2008 at 07:59:33PM +0800, Fengguang Wu wrote:
> On Sun, Jan 13, 2008 at 10:49:31AM +0100, Joerg Platte wrote:
> > register_jprobe(ext2_writepage) = 0
> > register_jprobe(requeue_io) = 0
> > register_kprobe(submit_bio) = 0
> > requeue_io:
> > inode 114019(sda7/.kde) count 2,2 size 0 pages 1
> > 0 2 0 U____
> > requeue_io:
> > inode 114025(sda7/cache-ibm) count 2,1 size 0 pages 1
> > 0 2 0 U____
> > requeue_io:
> > inode 114029(sda7/socket-ibm) count 2,3 size 0 pages 1
> > 0 2 0 U____
> > requeue_io:
> > inode 114017(sda7/0266584877) count 3,6 size 0 pages 1
> > 0 2 0 U____
>
> It helps. Thank you, Joerg!
>
> The .kde/cache-ibm/socket-ibm/0266584877 above are directories.
> It's weird that dirs would have their own mappings in ext2. In

Oh, ext2 dirs have their own mapping pages. Not the same with ext3.

> particular this bug is triggered because the dir mapping page has
> PAGECACHE_TAG_DIRTY set and PG_dirty cleared, staying in an
> inconsistent state.

Just found that a deleted dir will enter that inconsistent state when
someone still have reference to it...