tree 70e319ec3d804992c1dd11e5123547d0901a40a0
parent e34a314c5e49fe6b763568f6576b19f1299c33c2
author Dave Chinner <dchinner@redhat.com> 1296090852 +1100
committer Alex Elder <aelder@sgi.com> 1296227135 -0600

xfs: speculative delayed allocation uses rounddown_power_of_2 badly

rounddown_power_of_2() returns an undefined result when passed a
value of zero. The specualtive delayed allocation code is doing this
when the inode is zero length. Hence occasionally the preallocation
is much, much larger than is necessary (e.g. 8GB for a 270 _byte_
file). Ensure we don't even pass a zero value to this function so
the result of preallocation is always the desired size.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>