xfs: make sure aglen never goes negative in xfs_refcount_adjust_extents

Prior to calling xfs_refcount_adjust_extents, we trimmed agbno/aglen
such that the end of the range would not be in the middle of the record.
If this is no longer the case, something is seriously wrong with the
btree.  Bail out with a corruption error.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
1 file changed