rbd: get the latest osdmap when using an existing client

Currently we request the latest osdmap only if ceph_pg_poolid_by_name()
fails with -ENOENT.  This is effective with newly created pools, but we
also want to avoid attempting to map from pools that were recently
deleted and report "pool does not exist" instead.  (Such an attempt
eventually fails in the OSD client after map check code kicks in, but
the error message is confusing.)

Request the latest osdmap unconditionally after bumping a ref on an
existing client in rbd_client_find().
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

drivers/block/rbd.c

@@ -867,6 +867,23 @@ static void rbd_put_client(struct rbd_client *rbdc)
 		kref_put(&rbdc->kref, rbd_client_release);
 }
 
+static int wait_for_latest_osdmap(struct ceph_client *client)
+{
+	u64 newest_epoch;
+	int ret;
+
+	ret = ceph_monc_get_version(&client->monc, "osdmap", &newest_epoch);
+	if (ret)
+		return ret;
+
+	if (client->osdc.osdmap->epoch >= newest_epoch)
+		return 0;
+
+	ceph_osdc_maybe_request_map(&client->osdc);
+	return ceph_monc_wait_osdmap(&client->monc, newest_epoch,
+				     client->options->mount_timeout);
+}
+
 /*
  * Get a ceph client with specific addr and configuration, if one does
  * not exist create it.  Either way, ceph_opts is consumed by this
@@ -875,13 +892,26 @@ static void rbd_put_client(struct rbd_client *rbdc)
 static struct rbd_client *rbd_get_client(struct ceph_options *ceph_opts)
 {
 	struct rbd_client *rbdc;
+	int ret;
 
 	mutex_lock_nested(&client_mutex, SINGLE_DEPTH_NESTING);
 	rbdc = rbd_client_find(ceph_opts);
-	if (rbdc)	/* using an existing client */
+	if (rbdc) {
 		ceph_destroy_options(ceph_opts);
-	else
+
+		/*
+		 * Using an existing client.  Make sure ->pg_pools is up to
+		 * date before we look up the pool id in do_rbd_add().
+		 */
+		ret = wait_for_latest_osdmap(rbdc->client);
+		if (ret) {
+			rbd_warn(NULL, "failed to get latest osdmap: %d", ret);
+			rbd_put_client(rbdc);
+			rbdc = ERR_PTR(ret);
+		}
+	} else {
 		rbdc = rbd_client_create(ceph_opts);
+	}
 	mutex_unlock(&client_mutex);
 
 	return rbdc;
@@ -5185,39 +5215,6 @@ static int rbd_add_parse_args(const char *buf,
 	return ret;
 }
 
-/*
- * Return pool id (>= 0) or a negative error code.
- */
-static int rbd_add_get_pool_id(struct rbd_client *rbdc, const char *pool_name)
-{
-	struct ceph_options *opts = rbdc->client->options;
-	u64 newest_epoch;
-	int tries = 0;
-	int ret;
-
-again:
-	ret = ceph_pg_poolid_by_name(rbdc->client->osdc.osdmap, pool_name);
-	if (ret == -ENOENT && tries++ < 1) {
-		ret = ceph_monc_get_version(&rbdc->client->monc, "osdmap",
-					    &newest_epoch);
-		if (ret < 0)
-			return ret;
-
-		if (rbdc->client->osdc.osdmap->epoch < newest_epoch) {
-			ceph_osdc_maybe_request_map(&rbdc->client->osdc);
-			(void) ceph_monc_wait_osdmap(&rbdc->client->monc,
-						     newest_epoch,
-						     opts->mount_timeout);
-			goto again;
-		} else {
-			/* the osdmap we have is new enough */
-			return -ENOENT;
-		}
-	}
-
-	return ret;
-}
-
 static void rbd_dev_image_unlock(struct rbd_device *rbd_dev)
 {
 	down_write(&rbd_dev->lock_rwsem);
@@ -5646,7 +5643,7 @@ static ssize_t do_rbd_add(struct bus_type *bus,
 	}
 
 	/* pick the pool */
-	rc = rbd_add_get_pool_id(rbdc, spec->pool_name);
+	rc = ceph_pg_poolid_by_name(rbdc->client->osdc.osdmap, spec->pool_name);
 	if (rc < 0) {
 		if (rc == -ENOENT)
 			pr_info("pool %s does not exist\n", spec->pool_name);