libceph: introduce apply_temps() helper

apply_temp() helper for applying various temporary mappings (at this
point only pg_temp mappings) to the up set, therefore transforming it
into an acting set.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index b8bbef0580192e8c1027f48c0b309f4e82daf602..bd40f56b53eddce8666ae7dff6194514e177cfde 100644 (file)
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1596,6 +1596,58 @@ static int raw_to_up_osds(struct ceph_osdmap *osdmap,
        return len;
 }
 
+/*
+ * Given up set, apply pg_temp mapping.
+ *
+ * Return acting set length.  *primary is set to acting primary osd id,
+ * or -1 if acting set is empty.
+ */
+static int apply_temps(struct ceph_osdmap *osdmap,
+                      struct ceph_pg_pool_info *pool, struct ceph_pg pgid,
+                      int *osds, int len, int *primary)
+{
+       struct ceph_pg_mapping *pg;
+       int temp_len;
+       int temp_primary;
+       int i;
+
+       /* raw_pg -> pg */
+       pgid.seed = ceph_stable_mod(pgid.seed, pool->pg_num,
+                                   pool->pg_num_mask);
+
+       /* pg_temp? */
+       pg = __lookup_pg_mapping(&osdmap->pg_temp, pgid);
+       if (pg) {
+               temp_len = 0;
+               temp_primary = -1;
+
+               for (i = 0; i < pg->pg_temp.len; i++) {
+                       if (ceph_osd_is_down(osdmap, pg->pg_temp.osds[i])) {
+                               if (ceph_can_shift_osds(pool))
+                                       continue;
+                               else
+                                       osds[temp_len++] = CRUSH_ITEM_NONE;
+                       } else {
+                               osds[temp_len++] = pg->pg_temp.osds[i];
+                       }
+               }
+
+               /* apply pg_temp's primary */
+               for (i = 0; i < temp_len; i++) {
+                       if (osds[i] != CRUSH_ITEM_NONE) {
+                               temp_primary = osds[i];
+                               break;
+                       }
+               }
+       } else {
+               temp_len = len;
+               temp_primary = *primary;
+       }
+
+       *primary = temp_primary;
+       return temp_len;
+}
+
 /*
  * Return acting set for given pgid.
  */