Andrew Morton wrote:
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc3/2.6.12-rc3-mm2/
> 

http://www.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc3/2.6.12-rc3-mm2/broken-out/fix-race-in-block_write_full_page.patch

While this patch does fix the problem, I would like to propose the
following attached patch instead, which is a minimal fix for the
specific race identified.

I have the following concerns about extending the lock page coverage:
Extending lock_page coverage 1) doesn't appear to protect from any other
races; 2) doesn't seem to be how the rest of the kernel submits asynch
writes; 3) isn't how this path used to do locking; and 4) can hold the
page lock for a long time while a request slot and memory is allocated.

What's more, if there *is* a good reason to extend lock page coverage,
then that should probably be sumbmitted as a seperate changeset on top
of this minimal patch, with a seperate rationale. It would help future
work on this code identify why the locking is the way it is.


Thanks,
Nick

-- 
SUSE Labs, Novell Inc.