[PATCH] xfs: fix delalloc quota accounting on failure

[Christoph Hellwig]

On Tue, May 08, 2012 at 08:48:53PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> xfstest 270 was causing quota reservations way beyond what was sane
> (ten to hundreds of TB) for a 4GB filesystem. There's a sign problem
> in the error handling path of xfs_bmapi_reserve_delalloc() because
> xfs_trans_unreserve_quota_nblks() simple negates the value passed -
> which doesn't work for an unsigned variable. This causes
> reservations of close to 2^32 block instead of removing a
> reservation of a handful of blocks.
> 
> Fix the same problem in the other xfs_trans_unreserve_quota_nblks()
> callers where unsigned integer variables are used, too.

eww.  Wouldn't it be better to make handle that inside
xfs_trans_unreserve_quota_nblks?