libceph: introduce pg_to_raw_osds() and raw_to_up_osds() helpers

pg_to_raw_osds() helper for computing a raw (crush) set, which can
contain non-existant and down osds.

raw_to_up_osds() helper for pruning non-existant and down osds from the
raw set, therefore transforming it into an up set, and determining up
primary.

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 9568e62218524e8065912dc458a7cd1ab0822ffb..b8bbef0580192e8c1027f48c0b309f4e82daf602 100644 (file)
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1520,6 +1520,82 @@ static int *calc_pg_raw(struct ceph_osdmap *osdmap, struct ceph_pg pgid,
        return osds;
 }
 
+/*
+ * Calculate raw (crush) set for given pgid.
+ *
+ * Return raw set length, or error.
+ */
+static int pg_to_raw_osds(struct ceph_osdmap *osdmap,
+                         struct ceph_pg_pool_info *pool,
+                         struct ceph_pg pgid, u32 pps, int *osds)
+{
+       int ruleno;
+       int len;
+
+       /* crush */
+       ruleno = crush_find_rule(osdmap->crush, pool->crush_ruleset,
+                                pool->type, pool->size);
+       if (ruleno < 0) {
+               pr_err("no crush rule: pool %lld ruleset %d type %d size %d\n",
+                      pgid.pool, pool->crush_ruleset, pool->type,
+                      pool->size);
+               return -ENOENT;
+       }
+
+       len = do_crush(osdmap, ruleno, pps, osds,
+                      min_t(int, pool->size, CEPH_PG_MAX_SIZE),
+                      osdmap->osd_weight, osdmap->max_osd);
+       if (len < 0) {
+               pr_err("error %d from crush rule %d: pool %lld ruleset %d type %d size %d\n",
+                      len, ruleno, pgid.pool, pool->crush_ruleset,
+                      pool->type, pool->size);
+               return len;
+       }
+
+       return len;
+}
+
+/*
+ * Given raw set, calculate up set and up primary.
+ *
+ * Return up set length.  *primary is set to up primary osd id, or -1
+ * if up set is empty.
+ */
+static int raw_to_up_osds(struct ceph_osdmap *osdmap,
+                         struct ceph_pg_pool_info *pool,
+                         int *osds, int len, int *primary)
+{
+       int up_primary = -1;
+       int i;
+
+       if (ceph_can_shift_osds(pool)) {
+               int removed = 0;
+
+               for (i = 0; i < len; i++) {
+                       if (ceph_osd_is_down(osdmap, osds[i])) {
+                               removed++;
+                               continue;
+                       }
+                       if (removed)
+                               osds[i - removed] = osds[i];
+               }
+
+               len -= removed;
+               if (len > 0)
+                       up_primary = osds[0];
+       } else {
+               for (i = len - 1; i >= 0; i--) {
+                       if (ceph_osd_is_down(osdmap, osds[i]))
+                               osds[i] = CRUSH_ITEM_NONE;
+                       else
+                               up_primary = osds[i];
+               }
+       }
+
+       *primary = up_primary;
+       return len;
+}
+
 /*
  * Return acting set for given pgid.
  */