1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h
index acaa5615d634..4fad5f8ee01d 100644
--- a/include/linux/crush/crush.h
+++ b/include/linux/crush/crush.h
@@ -51,6 +51,7 @@ enum {
         CRUSH_RULE_SET_CHOOSELEAF_TRIES = 9, /* override chooseleaf_descend_once */
         CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES = 10,
         CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES = 11,
+        CRUSH_RULE_SET_CHOOSELEAF_VARY_R = 12
 };
 
 /*
@@ -173,6 +174,12 @@ struct crush_map {
          * apply to a collision: in that case we will retry as we used
          * to. */
         __u32 chooseleaf_descend_once;
+
+        /* if non-zero, feed r into chooseleaf, bit-shifted right by (r-1)
+         * bits.  a value of 1 is best for new clusters.  for legacy clusters
+         * that want to limit reshuffling, a value of 3 or 4 will make the
+         * mappings line up a bit better with previous mappings. */
+        __u8 chooseleaf_vary_r;
 };