7938 disable LBA weighting on files and SSDs
Reviewed by: Yuri Pankov <yuripv@gmx.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>

@@ -1660,11 +1660,11 @@
          * which is typically around 2:1.  We account for this by assigning
          * higher weight to lower metaslabs (multiplier ranging from 2x to 1x).
          * In effect, this means that we'll select the metaslab with the most
          * free bandwidth rather than simply the one with the most free space.
          */
-        if (metaslab_lba_weighting_enabled) {
+        if (!vd->vdev_nonrot && metaslab_lba_weighting_enabled) {
                 weight = 2 * weight - (msp->ms_id * weight) / vd->vdev_ms_count;
                 ASSERT(weight >= space && weight <= 2 * space);
         }
 
         /*