hi,

i've not run thru the whole report - but i think i've experienced the
same problem, the thread is: '2.6.24-rc6 reproducible raid5 hang'
and the solution was for my setup was to upgrade to 2.6.25-rc6
it doesn't occur using other fs - as a quick test you could try out
ext3/jfs

cheers,
kirk

Added linux-raid to cc - this is not an XFS problem

Cheers,

Dave.

On Wed, Mar 19, 2008 at 03:05:10PM +0000, David Flynn wrote:

quoted

We are currently experiencing a problem with writing to xfs on a 20disk
raid5 array.  It seems very similar to a post in 2007nov09:

  Re: 2.6.23.1: mdadm/raid5 hung/d-state

Using kernel 2.6.24.  Unlike the previous post the array was in a clean
state so no resync was occuring.  We are able to read from the array,
but any process that writes joins the list of blocked tasks

The machine is:
  2 of dual core opteron 280
  16GiB RAM
  4 lots of 5 sata disks connected to sil3124 sata hba.
  Running 2.6.24

There was a single rsync process accessing the array at the time
(~40MB/sec).

Random other bits[1]:
# cat /sys/block/md1/md/stripe_cache_active
256
# cat /sys/block/md1/md/stripe_cache_size  
256

Example of sysrq-w: