Hi all,
   I need some advice about this regression...

   Short version:
   With 2.6.32 my / partition (ext4 without journal) seems working
always in synchronous mode. No write caching, so the HD is always
working. It works as usual with 2.6.31.

   Long version:
   To replicate the problem I've used the bash script in attachment (test.sh)
   With 2.6.31.6 I have no work at all of the disk and incredible
speed results of dd (~400 MB/s), of course.
   With 2.6.32 I have the HD always working, and real speed numbers of
dd (~30MB/s).

   I bisected 2.6.32 and 2.6.31.6 version. In attach you can find the
log (bisect_log.txt).
   Reverting the last commit
(5534fb5bb35a62a94e0bd1fa2421f7fb6e894f10) gives the same behavior for
both kernel version.

   I investigated it because since using 2.6.32 my laptop temperature
became a lot higher, so much that my keybord keys were hot.
   Also, if I issue a sync I always have an immediate response, as I
was using "mount -o sync", ragrdless what I've done before.

Thanks a lot for your time and work,
Andrea