}
if (shift)
alloc_blocks >>= shift;
+
+ /*
+ * If we are still trying to allocate more space than is
+ * available, squash the prealloc hard. This can happen if we
+ * have a large file on a small filesystem and the above
+ * lowspace thresholds are smaller than MAXEXTLEN.
+ */
+ while (alloc_blocks >= freesp)
+ alloc_blocks >>= 4;
}
if (alloc_blocks < mp->m_writeio_blocks)