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>

1 files changed, 76 insertions, 0 deletions

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 9568e6221852..b8bbef058019 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1521,6 +1521,82 @@ static int *calc_pg_raw(struct ceph_osdmap *osdmap, struct ceph_pg pgid,
 }
 
 /*
+ * 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.
  */
 int ceph_calc_pg_acting(struct ceph_osdmap *osdmap, struct ceph_pg pgid,