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>

1 files changed, 52 insertions, 0 deletions

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index b8bbef058019..bd40f56b53ed 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1597,6 +1597,58 @@ static int raw_to_up_osds(struct ceph_osdmap *osdmap,
 }
 
 /*
+ * 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.
  */
 int ceph_calc_pg_acting(struct ceph_osdmap *osdmap, struct ceph_pg pgid,