ceph: fix crush CHOOSE_LEAF when type is already a leaf

We may not recurse for CHOOSE_LEAF if we start with a leaf node.  When
that happens, the out2 vector needs to be filled in with the result.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 25 insertions, 13 deletions

diff --git a/fs/ceph/crush/mapper.c b/fs/ceph/crush/mapper.c
index 804e6d53b77c..374266bddd9c 100644
--- a/fs/ceph/crush/mapper.c
+++ b/fs/ceph/crush/mapper.c
@@ -238,7 +238,7 @@ static int bucket_straw_choose(struct crush_bucket_straw *bucket,
 
 static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
 {
-        dprintk("choose %d x=%d r=%d\n", in->id, x, r);
+        dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
         switch (in->alg) {
         case CRUSH_BUCKET_UNIFORM:
                 return bucket_uniform_choose((struct crush_bucket_uniform *)in,
@@ -305,7 +305,9 @@ static int crush_choose(struct crush_map *map,
         int itemtype;
         int collide, reject;
         const int orig_tries = 5; /* attempts before we fall back to search */
-        dprintk("choose bucket %d x %d outpos %d\n", bucket->id, x, outpos);
+
+        dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
+                bucket->id, x, outpos, numrep);
 
         for (rep = outpos; rep < numrep; rep++) {
                 /* keep trying until we get a non-out, non-colliding item */
@@ -378,15 +380,25 @@ static int crush_choose(struct crush_map *map,
                                         }
                                 }
 
-                                if (recurse_to_leaf &&
-                                    item < 0 &&
-                                    crush_choose(map, map->buckets[-1-item],
-                                                 weight,
-                                                 x, outpos+1, 0,
-                                                 out2, outpos,
-                                                 firstn, 0, NULL) <= outpos) {
-                                        reject = 1;
-                                } else {
+                                reject = 0;
+                                if (recurse_to_leaf) {
+                                        if (item < 0) {
+                                                if (crush_choose(map,
+                                                         map->buckets[-1-item],
+                                                         weight,
+                                                         x, outpos+1, 0,
+                                                         out2, outpos,
+                                                         firstn, 0,
+                                                         NULL) <= outpos)
+                                                        /* didn't get leaf */
+                                                        reject = 1;
+                                        } else {
+                                                /* we already have a leaf! */
+                                                out2[outpos] = item;
+                                        }
+                                }
+
+                                if (!reject) {
                                         /* out? */
                                         if (itemtype == 0)
                                                 reject = is_out(map, weight,
@@ -425,12 +437,12 @@ reject:
                         continue;
                 }
 
-                dprintk("choose got %d\n", item);
+                dprintk("CHOOSE got %d\n", item);
                 out[outpos] = item;
                 outpos++;
         }
 
-        dprintk("choose returns %d\n", outpos);
+        dprintk("CHOOSE returns %d\n", outpos);
         return outpos;
 }