logstmt
[oweals/gnunet.git] / src / datastore / gnunet-service-datastore.c
index 74196dd1e794ad0e2d0cb00c5e531d3c6f1de293..a0d5f7babe649745b73338ab74eea9a57dbd7f49 100644 (file)
  * @file datastore/gnunet-service-datastore.c
  * @brief Management for the datastore for files stored on a GNUnet node
  * @author Christian Grothoff
- *
- * TODO:
- * quota management code:
- * - track storage use
- * - track reservations
- * - refuse above-quota
- * - content expiration job
- * - near-quota low-priority content discard job
  */
 
 #include "platform.h"
 #include "gnunet_util_lib.h"
 #include "gnunet_protocols.h"
-#include "plugin_datastore.h"
+#include "gnunet_statistics_service.h"
+#include "gnunet_datastore_plugin.h"
 #include "datastore.h"
 
 /**
  */
 #define MAX_PENDING 1024
 
+/**
+ * How long are we at most keeping "expired" content
+ * past the expiration date in the database?
+ */
+#define MAX_EXPIRE_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 15)
+
+/**
+ * How fast are we allowed to query the database for deleting
+ * expired content? (1 item per second).
+ */
+#define MIN_EXPIRE_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1)
+
+
+#define QUOTA_STAT_NAME gettext_noop ("# bytes used in file-sharing datastore")
+
+/**
+ * After how many payload-changing operations
+ * do we sync our statistics?
+ */
+#define MAX_STAT_SYNC_LAG 50
+
 
 /**
  * Our datastore plugin.
@@ -109,6 +123,7 @@ struct ReservationList
 };
 
 
+
 /**
  * Our datastore plugin (NULL if not available).
  */
@@ -125,56 +140,329 @@ static struct ReservationList *reservations;
 static struct GNUNET_CONTAINER_BloomFilter *filter;
 
 /**
- * Static counter to produce reservation identifiers.
+ * How much space are we allowed to use?
+ */
+static unsigned long long quota;
+
+/**
+ * How much space are we using for the cache?  (space available for
+ * insertions that will be instantly reclaimed by discarding less
+ * important content --- or possibly whatever we just inserted into
+ * the "cache").
  */
-static int reservation_gen;
+static unsigned long long cache_size;
 
 /**
- * How much space are we allowed to use?
+ * How much space have we currently reserved?
  */
-static unsigned long long quota;
+static unsigned long long reserved;
+  
+/**
+ * How much data are we currently storing
+ * in the database?
+ */
+static unsigned long long payload;
 
+/**
+ * Number of updates that were made to the
+ * payload value since we last synchronized
+ * it with the statistics service.
+ */
+static unsigned int lastSync;
 
 /**
- * Function called once the transmit operation has
- * either failed or succeeded.
- *
- * @param cls closure
- * @param status GNUNET_OK on success, GNUNET_SYSERR on error
+ * Did we get an answer from statistics?
+ */
+static int stats_worked;
+
+/**
+ * Identity of the task that is used to delete
+ * expired content.
  */
-typedef void (*TransmitContinuation)(void *cls,
-                                    int status);
+static GNUNET_SCHEDULER_TaskIdentifier expired_kill_task;
 
+/**
+ * Our configuration.
+ */
+const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+
+/**
+ * Handle for reporting statistics.
+ */
+static struct GNUNET_STATISTICS_Handle *stats;
+
+
+/**
+ * Synchronize our utilization statistics with the 
+ * statistics service.
+ */
+static void 
+sync_stats ()
+{
+  GNUNET_STATISTICS_set (stats,
+                        QUOTA_STAT_NAME,
+                        payload,
+                        GNUNET_YES);
+  lastSync = 0;
+}
+
+
+
+/**
+ * Context for transmitting replies to clients.
+ */
 struct TransmitCallbackContext 
 {
+  
   /**
-   * The message that we're asked to transmit.
+   * We keep these in a doubly-linked list (for cleanup).
    */
-  struct GNUNET_MessageHeader *msg;
-
+  struct TransmitCallbackContext *next;
+  
   /**
-   * Client that we are transmitting to.
+   * We keep these in a doubly-linked list (for cleanup).
    */
-  struct GNUNET_SERVER_Client *client;
-
+  struct TransmitCallbackContext *prev;
+  
   /**
-   * Function to call once msg has been transmitted
-   * (or at least added to the buffer).
+   * The message that we're asked to transmit.
    */
-  TransmitContinuation tc;
-
+  struct GNUNET_MessageHeader *msg;
+  
   /**
-   * Closure for tc.
+   * Handle for the transmission request.
    */
-  void *tc_cls;
+  struct GNUNET_CONNECTION_TransmitHandle *th;
 
   /**
-   * GNUNET_YES if we are supposed to signal the server
-   * completion of the client's request.
+   * Client that we are transmitting to.
    */
-  int end;
+  struct GNUNET_SERVER_Client *client;
+
 };
 
+  
+/**
+ * Head of the doubly-linked list (for cleanup).
+ */
+static struct TransmitCallbackContext *tcc_head;
+
+/**
+ * Tail of the doubly-linked list (for cleanup).
+ */
+static struct TransmitCallbackContext *tcc_tail;
+
+/**
+ * Have we already cleaned up the TCCs and are hence no longer
+ * willing (or able) to transmit anything to anyone?
+ */
+static int cleaning_done;
+
+/**
+ * Handle for pending get request.
+ */
+static struct GNUNET_STATISTICS_GetHandle *stat_get;
+
+
+/**
+ * Task that is used to remove expired entries from
+ * the datastore.  This task will schedule itself
+ * again automatically to always delete all expired
+ * content quickly.
+ *
+ * @param cls not used
+ * @param tc task context
+ */ 
+static void
+delete_expired (void *cls,
+               const struct GNUNET_SCHEDULER_TaskContext *tc);
+
+
+/**
+ * Iterate over the expired items stored in the datastore.
+ * Delete all expired items; once we have processed all
+ * expired items, re-schedule the "delete_expired" task.
+ *
+ * @param cls not used
+ * @param next_cls closure to pass to the "next" function.
+ * @param key key for the content
+ * @param size number of bytes in data
+ * @param data content stored
+ * @param type type of the content
+ * @param priority priority of the content
+ * @param anonymity anonymity-level for the content
+ * @param expiration expiration time for the content
+ * @param uid unique identifier for the datum;
+ *        maybe 0 if no unique identifier is available
+ *
+ * @return GNUNET_SYSERR to abort the iteration, GNUNET_OK to continue
+ *         (continue on call to "next", of course),
+ *         GNUNET_NO to delete the item and continue (if supported)
+ */
+static int 
+expired_processor (void *cls,
+                  const GNUNET_HashCode * key,
+                  uint32_t size,
+                  const void *data,
+                  enum GNUNET_BLOCK_Type type,
+                  uint32_t priority,
+                  uint32_t anonymity,
+                  struct GNUNET_TIME_Absolute
+                  expiration, 
+                  uint64_t uid)
+{
+  struct GNUNET_TIME_Absolute now;
+
+  if (key == NULL) 
+    {
+      expired_kill_task 
+       = GNUNET_SCHEDULER_add_delayed (MAX_EXPIRE_DELAY,
+                                       &delete_expired,
+                                       NULL);
+      return GNUNET_SYSERR;
+    }
+  now = GNUNET_TIME_absolute_get ();
+  if (expiration.abs_value > now.abs_value)
+    {
+      /* finished processing */
+      expired_kill_task 
+       = GNUNET_SCHEDULER_add_delayed (MAX_EXPIRE_DELAY,
+                                       &delete_expired,
+                                       NULL);
+      return GNUNET_SYSERR;
+    }
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Deleting content `%s' of type %u that expired %llu ms ago\n",
+             GNUNET_h2s (key),
+             type,
+             (unsigned long long) (now.abs_value - expiration.abs_value));
+#endif
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# bytes expired"),
+                           size,
+                           GNUNET_YES);
+  GNUNET_CONTAINER_bloomfilter_remove (filter,
+                                      key);
+  expired_kill_task 
+    = GNUNET_SCHEDULER_add_delayed (MIN_EXPIRE_DELAY,
+                                   &delete_expired,
+                                   NULL);
+  return GNUNET_NO;
+}
+
+
+/**
+ * Task that is used to remove expired entries from
+ * the datastore.  This task will schedule itself
+ * again automatically to always delete all expired
+ * content quickly.
+ *
+ * @param cls not used
+ * @param tc task context
+ */ 
+static void
+delete_expired (void *cls,
+               const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  expired_kill_task = GNUNET_SCHEDULER_NO_TASK;
+  plugin->api->get_expiration (plugin->api->cls, 
+                              &expired_processor,
+                              NULL);
+}
+
+
+/**
+ * An iterator over a set of items stored in the datastore
+ * that deletes until we're happy with respect to our quota.
+ *
+ * @param cls closure
+ * @param next_cls closure to pass to the "next" function.
+ * @param key key for the content
+ * @param size number of bytes in data
+ * @param data content stored
+ * @param type type of the content
+ * @param priority priority of the content
+ * @param anonymity anonymity-level for the content
+ * @param expiration expiration time for the content
+ * @param uid unique identifier for the datum;
+ *        maybe 0 if no unique identifier is available
+ *
+ * @return GNUNET_SYSERR to abort the iteration, GNUNET_OK to continue
+ *         (continue on call to "next", of course),
+ *         GNUNET_NO to delete the item and continue (if supported)
+ */
+static int 
+quota_processor (void *cls,
+                const GNUNET_HashCode * key,
+                uint32_t size,
+                const void *data,
+                enum GNUNET_BLOCK_Type type,
+                uint32_t priority,
+                uint32_t anonymity,
+                struct GNUNET_TIME_Absolute expiration, 
+                uint64_t uid)
+{
+  unsigned long long *need = cls;
+
+  if (NULL == key)
+    return GNUNET_SYSERR;    
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Deleting %llu bytes of low-priority content `%s' of type %u (still trying to free another %llu bytes)\n",
+             (unsigned long long) (size + GNUNET_DATASTORE_ENTRY_OVERHEAD),
+             GNUNET_h2s (key),
+             type,
+             *need);
+#endif
+  if (size + GNUNET_DATASTORE_ENTRY_OVERHEAD > *need)
+    *need = 0;
+  else
+    *need -= size + GNUNET_DATASTORE_ENTRY_OVERHEAD;
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# bytes purged (low-priority)"),
+                           size,
+                           GNUNET_YES);
+  GNUNET_CONTAINER_bloomfilter_remove (filter,
+                                      key);
+  return GNUNET_NO;
+}
+
+
+/**
+ * Manage available disk space by running tasks
+ * that will discard content if necessary.  This
+ * function will be run whenever a request for
+ * "need" bytes of storage could only be satisfied
+ * by eating into the "cache" (and we want our cache
+ * space back).
+ *
+ * @param need number of bytes of content that were
+ *        placed into the "cache" (and hence the
+ *        number of bytes that should be removed).
+ */
+static void
+manage_space (unsigned long long need)
+{
+  unsigned long long last;
+
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Asked to free up %llu bytes of cache space\n",
+             need);
+#endif
+  last = 0;
+  while ( (need > 0) &&
+         (last != need) )
+    {
+      last = need;
+      plugin->api->get_expiration (plugin->api->cls,
+                                  &quota_processor,
+                                  &need);    
+    }
+}
+
 
 /**
  * Function called to notify a client about the socket
@@ -194,42 +482,25 @@ transmit_callback (void *cls,
   struct TransmitCallbackContext *tcc = cls;
   size_t msize;
   
+  tcc->th = NULL;
+  GNUNET_CONTAINER_DLL_remove (tcc_head,
+                              tcc_tail,
+                              tcc);
   msize = ntohs(tcc->msg->size);
   if (size == 0)
     {
-#if DEBUG_DATASTORE
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                 "Transmission failed.\n");
-#endif
-      if (tcc->tc != NULL)
-       tcc->tc (tcc->tc_cls, GNUNET_SYSERR);
-      if (GNUNET_YES == tcc->end)
-       {
-         GNUNET_SERVER_receive_done (tcc->client, GNUNET_SYSERR);
-       }
+                 _("Transmission to client failed!\n"));
+      GNUNET_SERVER_receive_done (tcc->client, GNUNET_SYSERR);       
+      GNUNET_SERVER_client_drop (tcc->client);
       GNUNET_free (tcc->msg);
       GNUNET_free (tcc);
       return 0;
     }
   GNUNET_assert (size >= msize);
   memcpy (buf, tcc->msg, msize);
-  if (tcc->tc != NULL)
-    tcc->tc (tcc->tc_cls, GNUNET_OK);
-  if (GNUNET_YES == tcc->end)
-    {
-#if DEBUG_DATASTORE
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                 "Request completed, ready for the next request!\n");
-#endif
-      GNUNET_SERVER_receive_done (tcc->client, GNUNET_OK);
-    }
-  else
-    {
-#if DEBUG_DATASTORE
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                 "Response transmitted, more pending!\n");
-#endif
-    }
+  GNUNET_SERVER_receive_done (tcc->client, GNUNET_OK);
+  GNUNET_SERVER_client_drop (tcc->client);
   GNUNET_free (tcc->msg);
   GNUNET_free (tcc);
   return msize;
@@ -241,47 +512,45 @@ transmit_callback (void *cls,
  *
  * @param client target of the message
  * @param msg message to transmit, will be freed!
- * @param end is this the last response (and we should
- *        signal the server completion accodingly after
- *        transmitting this message)?
+ * @param tc function to call afterwards
+ * @param tc_cls closure for tc
  */
 static void
 transmit (struct GNUNET_SERVER_Client *client,
-         struct GNUNET_MessageHeader *msg,
-         TransmitContinuation tc,
-         void *tc_cls,
-         int end)
+         struct GNUNET_MessageHeader *msg)
 {
   struct TransmitCallbackContext *tcc;
 
+  if (GNUNET_YES == cleaning_done)
+    {
+#if DEBUG_DATASTORE
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                 "Shutdown in progress, aborting transmission.\n");
+#endif
+      GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+      GNUNET_free (msg);
+      return;
+    }
   tcc = GNUNET_malloc (sizeof(struct TransmitCallbackContext));
   tcc->msg = msg;
   tcc->client = client;
-  tcc->tc = tc;
-  tcc->tc_cls = tc_cls;
-  tcc->end = end;
-
   if (NULL ==
-      GNUNET_SERVER_notify_transmit_ready (client,
-                                          ntohs(msg->size),
-                                          GNUNET_TIME_UNIT_FOREVER_REL,
-                                          &transmit_callback,
-                                          tcc))
+      (tcc->th = GNUNET_SERVER_notify_transmit_ready (client,
+                                                     ntohs(msg->size),
+                                                     GNUNET_TIME_UNIT_FOREVER_REL,
+                                                     &transmit_callback,
+                                                     tcc)))
     {
       GNUNET_break (0);
-      if (GNUNET_YES == end)
-       {
-#if DEBUG_DATASTORE
-         GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                     "Disconnecting client.\n");
-#endif   
-         GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
-       }
-      if (NULL != tc)
-       tc (tc_cls, GNUNET_SYSERR);
+      GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
       GNUNET_free (msg);
       GNUNET_free (tcc);
+      return;
     }
+  GNUNET_SERVER_client_keep (client);
+  GNUNET_CONTAINER_DLL_insert (tcc_head,
+                              tcc_tail,
+                              tcc);
 }
 
 
@@ -302,7 +571,7 @@ transmit_status (struct GNUNET_SERVER_Client *client,
 
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Transmitting `%s' message with value %d and message %s\n",
+             "Transmitting `%s' message with value %d and message `%s'\n",
              "STATUS",
              code,
              msg != NULL ? msg : "(none)");
@@ -312,32 +581,12 @@ transmit_status (struct GNUNET_SERVER_Client *client,
   sm->header.size = htons(sizeof(struct StatusMessage) + slen);
   sm->header.type = htons(GNUNET_MESSAGE_TYPE_DATASTORE_STATUS);
   sm->status = htonl(code);
-  memcpy (&sm[1], msg, slen);  
-  transmit (client, &sm->header, NULL, NULL, GNUNET_YES);
+  if (slen > 0)
+    memcpy (&sm[1], msg, slen);  
+  transmit (client, &sm->header);
 }
 
 
-/**
- * Function called once the transmit operation has
- * either failed or succeeded.
- *
- * @param cls closure
- * @param status GNUNET_OK on success, GNUNET_SYSERR on error
- */
-static void 
-get_next(void *next_cls,
-        int status)
-{
-  if (status != GNUNET_OK)
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                 _("Failed to transmit an item to the client; aborting iteration.\n"));    
-      plugin->api->next_request (next_cls, GNUNET_YES);
-      return;
-    }
-  plugin->api->next_request (next_cls, GNUNET_NO);
-}
-
 
 /**
  * Function that will transmit the given datastore entry
@@ -360,11 +609,10 @@ get_next(void *next_cls,
  */
 static int
 transmit_item (void *cls,
-              void *next_cls,
               const GNUNET_HashCode * key,
               uint32_t size,
               const void *data,
-              uint32_t type,
+              enum GNUNET_BLOCK_Type type,
               uint32_t priority,
               uint32_t anonymity,
               struct GNUNET_TIME_Absolute
@@ -385,10 +633,11 @@ transmit_item (void *cls,
       end = GNUNET_malloc (sizeof(struct GNUNET_MessageHeader));
       end->size = htons(sizeof(struct GNUNET_MessageHeader));
       end->type = htons(GNUNET_MESSAGE_TYPE_DATASTORE_DATA_END);
-      transmit (client, end, NULL, NULL, GNUNET_YES);
+      transmit (client, end);
       GNUNET_SERVER_client_drop (client);
       return GNUNET_OK;
     }
+  GNUNET_assert (sizeof (struct DataMessage) + size < GNUNET_SERVER_MAX_MESSAGE_SIZE);
   dm = GNUNET_malloc (sizeof(struct DataMessage) + size);
   dm->header.size = htons(sizeof(struct DataMessage) + size);
   dm->header.type = htons(GNUNET_MESSAGE_TYPE_DATASTORE_DATA);
@@ -397,16 +646,26 @@ transmit_item (void *cls,
   dm->type = htonl(type);
   dm->priority = htonl(priority);
   dm->anonymity = htonl(anonymity);
+  dm->replication = htonl (0);
+  dm->reserved = htonl (0);
   dm->expiration = GNUNET_TIME_absolute_hton(expiration);
   dm->uid = GNUNET_htonll(uid);
   dm->key = *key;
   memcpy (&dm[1], data, size);
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Transmitting `%s' message\n",
-             "DATA");
+             "Transmitting `%s' message for `%s' of type %u with expiration %llu (now: %llu)\n",
+             "DATA",
+             GNUNET_h2s (key),
+             type,
+             (unsigned long long) expiration.abs_value,
+             (unsigned long long) GNUNET_TIME_absolute_get ().abs_value);
 #endif
-  transmit (client, &dm->header, &get_next, next_cls, GNUNET_NO);
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# results found"),
+                           1,
+                           GNUNET_NO);
+  transmit (client, &dm->header);
   return GNUNET_OK;
 }
 
@@ -420,24 +679,72 @@ transmit_item (void *cls,
  */
 static void
 handle_reserve (void *cls,
-            struct GNUNET_SERVER_Client *client,
-            const struct GNUNET_MessageHeader *message)
+               struct GNUNET_SERVER_Client *client,
+               const struct GNUNET_MessageHeader *message)
 {
+  /**
+   * Static counter to produce reservation identifiers.
+   */
+  static int reservation_gen;
+
   const struct ReserveMessage *msg = (const struct ReserveMessage*) message;
   struct ReservationList *e;
+  unsigned long long used;
+  unsigned long long req;
+  uint64_t amount;
+  uint32_t entries;
 
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Processing `%s' request\n",
              "RESERVE");
 #endif
- /* FIXME: check if we have that much space... */
+  amount = GNUNET_ntohll(msg->amount);
+  entries = ntohl(msg->entries);
+  used = payload + reserved;
+  req = amount + ((unsigned long long) GNUNET_DATASTORE_ENTRY_OVERHEAD) * entries;
+  if (used + req > quota)
+    {
+      if (quota < used)
+       used = quota; /* cheat a bit for error message (to avoid negative numbers) */
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                 _("Insufficient space (%llu bytes are available) to satisfy `%s' request for %llu bytes\n"),
+                 quota - used,
+                 "RESERVE",
+                 req);
+      if (cache_size < req)
+       {
+         /* TODO: document this in the FAQ; essentially, if this
+            message happens, the insertion request could be blocked
+            by less-important content from migration because it is
+            larger than 1/8th of the overall available space, and
+            we only reserve 1/8th for "fresh" insertions */
+         GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                     _("The requested amount (%llu bytes) is larger than the cache size (%llu bytes)\n"),
+                     req,
+                     cache_size);
+         transmit_status (client, 0, 
+                          gettext_noop ("Insufficient space to satisfy request and "
+                                        "requested amount is larger than cache size"));
+       }
+      else
+       {
+         transmit_status (client, 0, 
+                          gettext_noop ("Insufficient space to satisfy request"));
+       }
+      return;      
+    }
+  reserved += req;
+  GNUNET_STATISTICS_set (stats,
+                        gettext_noop ("# reserved"),
+                        reserved,
+                        GNUNET_NO);
   e = GNUNET_malloc (sizeof(struct ReservationList));
   e->next = reservations;
   reservations = e;
   e->client = client;
-  e->amount = GNUNET_ntohll(msg->amount);
-  e->entries = GNUNET_ntohll(msg->entries);
+  e->amount = amount;
+  e->entries = entries;
   e->rid = ++reservation_gen;
   if (reservation_gen < 0)
     reservation_gen = 0; /* wrap around */
@@ -462,6 +769,7 @@ handle_release_reserve (void *cls,
   struct ReservationList *prev;
   struct ReservationList *next;
   int rid = ntohl(msg->rid);
+  unsigned long long rem;
 
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
@@ -479,15 +787,26 @@ handle_release_reserve (void *cls,
            reservations = next;
          else
            prev->next = next;
-         /* FIXME: released remaining reserved space! */
+         rem = pos->amount + ((unsigned long long) GNUNET_DATASTORE_ENTRY_OVERHEAD) * pos->entries;
+         GNUNET_assert (reserved >= rem);
+         reserved -= rem;
+         GNUNET_STATISTICS_set (stats,
+                        gettext_noop ("# reserved"),
+                                reserved,
+                                GNUNET_NO);
+#if DEBUG_DATASTORE
+         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                     "Returning %llu remaining reserved bytes to storage pool\n",
+                     rem);
+#endif   
          GNUNET_free (pos);
          transmit_status (client, GNUNET_OK, NULL);
          return;
        }       
       prev = pos;
-      pos = next;
     }
-  transmit_status (client, GNUNET_SYSERR, "Could not find matching reservation");
+  GNUNET_break (0);
+  transmit_status (client, GNUNET_SYSERR, gettext_noop ("Could not find matching reservation"));
 }
 
 
@@ -516,12 +835,151 @@ check_data (const struct GNUNET_MessageHeader *message)
       GNUNET_break (0);
       return NULL;
     }
-  if (ntohl(dm->type) == 0) 
+  return dm;
+}
+
+
+/**
+ * Context for a put request used to see if the content is
+ * already present.
+ */
+struct PutContext
+{
+  /**
+   * Client to notify on completion.
+   */
+  struct GNUNET_SERVER_Client *client;
+  
+  /* followed by the 'struct DataMessage' */
+};
+
+
+/**
+ * Actually put the data message.
+ */
+static void
+execute_put (struct GNUNET_SERVER_Client *client,
+            const struct DataMessage *dm)
+{
+  uint32_t size;
+  char *msg;
+  int ret;
+
+  size = ntohl(dm->size);
+  msg = NULL;
+  ret = plugin->api->put (plugin->api->cls,
+                         &dm->key,
+                         size,
+                         &dm[1],
+                         ntohl(dm->type),
+                         ntohl(dm->priority),
+                         ntohl(dm->anonymity),
+                         ntohl(dm->replication),
+                         GNUNET_TIME_absolute_ntoh(dm->expiration),
+                         &msg);
+  if (GNUNET_OK == ret)
     {
-      GNUNET_break (0);
-      return NULL;
+      GNUNET_STATISTICS_update (stats,
+                               gettext_noop ("# bytes stored"),
+                               size,
+                               GNUNET_YES);
+      GNUNET_CONTAINER_bloomfilter_add (filter,
+                                       &dm->key);
+#if DEBUG_DATASTORE
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                 "Successfully stored %u bytes of type %u under key `%s'\n",
+                 size,
+                 ntohl(dm->type),
+                 GNUNET_h2s (&dm->key));
+#endif
     }
-  return dm;
+  transmit_status (client, 
+                  ret,
+                  msg);
+  GNUNET_free_non_null (msg);
+  if (quota - reserved - cache_size < payload)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                 _("Need %llu bytes more space (%llu allowed, using %llu)\n"),
+                 (unsigned long long) size + GNUNET_DATASTORE_ENTRY_OVERHEAD,
+                 (unsigned long long) (quota - reserved - cache_size),
+                 (unsigned long long) payload);
+      manage_space (size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
+    }
+}
+
+
+/**
+ * Function that will check if the given datastore entry
+ * matches the put and if none match executes the put.
+ *
+ * @param cls closure, pointer to the client (of type 'struct PutContext').
+ * @param key key for the content
+ * @param size number of bytes in data
+ * @param data content stored
+ * @param type type of the content
+ * @param priority priority of the content
+ * @param anonymity anonymity-level for the content
+ * @param expiration expiration time for the content
+ * @param uid unique identifier for the datum;
+ *        maybe 0 if no unique identifier is available
+ *
+ * @return GNUNET_OK usually
+ *         GNUNET_NO to delete the item 
+ */
+static int
+check_present (void *cls,
+              const GNUNET_HashCode * key,
+              uint32_t size,
+              const void *data,
+              enum GNUNET_BLOCK_Type type,
+              uint32_t priority,
+              uint32_t anonymity,
+              struct GNUNET_TIME_Absolute
+              expiration, uint64_t uid)
+{
+  struct PutContext *pc = cls;
+  const struct DataMessage *dm;
+
+  dm = (const struct DataMessage*) &pc[1];
+  if (key == NULL)
+    {
+      execute_put (pc->client, dm);
+      GNUNET_SERVER_client_drop (pc->client);
+      GNUNET_free (pc);
+      return GNUNET_OK;
+    }
+  if ( (GNUNET_BLOCK_TYPE_FS_DBLOCK == type) ||
+       (GNUNET_BLOCK_TYPE_FS_IBLOCK == type) ||
+       ( (size == ntohl(dm->size)) &&
+        (0 == memcmp (&dm[1],
+                      data,
+                      size)) ) )
+    {
+#if DEBUG_MYSQL
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                 "Result already present in datastore\n");
+#endif
+      /* FIXME: change API to allow increasing 'replication' counter */
+      if ( (ntohl (dm->priority) > 0) ||
+          (GNUNET_TIME_absolute_ntoh(dm->expiration).abs_value >
+           expiration.abs_value) )
+       plugin->api->update (plugin->api->cls,
+                            uid,
+                            (int32_t) ntohl(dm->priority),
+                            GNUNET_TIME_absolute_ntoh(dm->expiration),
+                            NULL);
+      transmit_status (pc->client, GNUNET_NO, NULL);
+      GNUNET_SERVER_client_drop (pc->client);
+      GNUNET_free (pc);
+    }
+  else
+    {
+      execute_put (pc->client, dm);
+      GNUNET_SERVER_client_drop (pc->client);
+      GNUNET_free (pc);
+    }
+  return GNUNET_OK;
 }
 
 
@@ -538,43 +996,66 @@ handle_put (void *cls,
            const struct GNUNET_MessageHeader *message)
 {
   const struct DataMessage *dm = check_data (message);
-  char *msg;
-  int ret;
   int rid;
+  struct ReservationList *pos;
+  struct PutContext *pc;
+  GNUNET_HashCode vhash;
+  uint32_t size;
 
-#if DEBUG_DATASTORE
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Processing `%s' request\n",
-             "PUT");
-#endif
-  if (dm == NULL)
+  if ( (dm == NULL) ||
+       (ntohl(dm->type) == 0) ) 
     {
       GNUNET_break (0);
       GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
       return;
     }
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Processing `%s' request for `%s' of type %u\n",
+             "PUT",
+             GNUNET_h2s (&dm->key),
+             ntohl (dm->type));
+#endif
   rid = ntohl(dm->rid);
+  size = ntohl(dm->size);
   if (rid > 0)
     {
-      /* FIXME: find reservation, update remaining! */
+      pos = reservations;
+      while ( (NULL != pos) &&
+             (rid != pos->rid) )
+       pos = pos->next;
+      GNUNET_break (pos != NULL);
+      if (NULL != pos)
+       {
+         GNUNET_break (pos->entries > 0);
+         GNUNET_break (pos->amount >= size);
+         pos->entries--;
+         pos->amount -= size;
+         reserved -= (size + GNUNET_DATASTORE_ENTRY_OVERHEAD);
+         GNUNET_STATISTICS_set (stats,
+                                gettext_noop ("# reserved"),
+                                reserved,
+                                GNUNET_NO);
+       }
     }
-  msg = NULL;
-  ret = plugin->api->put (plugin->api->cls,
-                         &dm->key,
-                         ntohl(dm->size),
-                         &dm[1],
-                         ntohl(dm->type),
-                         ntohl(dm->priority),
-                         ntohl(dm->anonymity),
-                         GNUNET_TIME_absolute_ntoh(dm->expiration),
-                         &msg);
-  if (GNUNET_OK == ret)
-    GNUNET_CONTAINER_bloomfilter_add (filter,
-                                     &dm->key);
-  transmit_status (client, 
-                  (GNUNET_SYSERR == ret) ? GNUNET_SYSERR : GNUNET_OK, 
-                  msg);
-  GNUNET_free_non_null (msg);
+  if (GNUNET_YES == GNUNET_CONTAINER_bloomfilter_test (filter,
+                                                      &dm->key))
+    {
+      GNUNET_CRYPTO_hash (&dm[1], size, &vhash);
+      pc = GNUNET_malloc (sizeof (struct PutContext) + size + sizeof (struct DataMessage));
+      pc->client = client;
+      GNUNET_SERVER_client_keep (client);
+      memcpy (&pc[1], dm, size + sizeof (struct DataMessage));
+      plugin->api->get_key (plugin->api->cls,
+                           0,
+                           &dm->key,
+                           &vhash,
+                           ntohl (dm->type),
+                           &check_present,
+                           pc);      
+      return;
+    }
+  execute_put (client, dm);
 }
 
 
@@ -587,18 +1068,12 @@ handle_put (void *cls,
  */
 static void
 handle_get (void *cls,
-            struct GNUNET_SERVER_Client *client,
-            const struct GNUNET_MessageHeader *message)
+           struct GNUNET_SERVER_Client *client,
+           const struct GNUNET_MessageHeader *message)
 {
-  static struct GNUNET_TIME_Absolute zero;
   const struct GetMessage *msg;
   uint16_t size;
 
-#if DEBUG_DATASTORE
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Processing `%s' request\n",
-             "GET");
-#endif
   size = ntohs(message->size);
   if ( (size != sizeof(struct GetMessage)) &&
        (size != sizeof(struct GetMessage) - sizeof(GNUNET_HashCode)) )
@@ -608,6 +1083,18 @@ handle_get (void *cls,
       return;
     }
   msg = (const struct GetMessage*) message;
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Processing `%s' request for `%s' of type %u\n",
+             "GET",
+             GNUNET_h2s (&msg->key),
+             ntohl (msg->type));
+#endif
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# GET requests received"),
+                           1,
+                           GNUNET_NO);
+  GNUNET_SERVER_client_keep (client);
   if ( (size == sizeof(struct GetMessage)) &&
        (GNUNET_YES != GNUNET_CONTAINER_bloomfilter_test (filter,
                                                         &msg->key)) )
@@ -615,20 +1102,26 @@ handle_get (void *cls,
       /* don't bother database... */
 #if DEBUG_DATASTORE
       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                 "Empty result set for `%s' request.\n",
-                 "GET");
+                 "Empty result set for `%s' request for `%s' (bloomfilter).\n",
+                 "GET",
+                 GNUNET_h2s (&msg->key));
 #endif 
+      GNUNET_STATISTICS_update (stats,
+                               gettext_noop ("# requests filtered by bloomfilter"),
+                               1,
+                               GNUNET_NO);
       transmit_item (client,
-                    NULL, NULL, 0, NULL, 0, 0, 0, zero, 0);
+                    NULL, 0, NULL, 0, 0, 0, 
+                    GNUNET_TIME_UNIT_ZERO_ABS, 0);
       return;
     }
-  GNUNET_SERVER_client_keep (client);
-  plugin->api->get (plugin->api->cls,
-                   ((size == sizeof(struct GetMessage)) ? &msg->key : NULL),
-                   NULL,
-                   ntohl(msg->type),
-                   &transmit_item,
-                   client);    
+  plugin->api->get_key (plugin->api->cls,
+                       GNUNET_ntohll (msg->offset),
+                       ((size == sizeof(struct GetMessage)) ? &msg->key : NULL),
+                       NULL,
+                       ntohl(msg->type),
+                       &transmit_item,
+                       client);    
 }
 
 
@@ -648,13 +1141,18 @@ handle_update (void *cls,
   int ret;
   char *emsg;
 
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# UPDATE requests received"),
+                           1,
+                           GNUNET_NO);
+  msg = (const struct UpdateMessage*) message;
+  emsg = NULL;
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Processing `%s' request\n",
-             "UPDATE");
+             "Processing `%s' request for %llu\n",
+             "UPDATE",
+             (unsigned long long) GNUNET_ntohll (msg->uid));
 #endif
-  msg = (const struct UpdateMessage*) message;
-  emsg = NULL;
   ret = plugin->api->update (plugin->api->cls,
                             GNUNET_ntohll(msg->uid),
                             (int32_t) ntohl(msg->priority),
@@ -666,45 +1164,71 @@ handle_update (void *cls,
 
 
 /**
- * Handle GET_RANDOM-message.
+ * Handle GET_REPLICATION-message.
  *
  * @param cls closure
  * @param client identification of the client
  * @param message the actual message
  */
 static void
-handle_get_random (void *cls,
-                  struct GNUNET_SERVER_Client *client,
-                  const struct GNUNET_MessageHeader *message)
+handle_get_replication (void *cls,
+                       struct GNUNET_SERVER_Client *client,
+                       const struct GNUNET_MessageHeader *message)
 {
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Processing `%s' request\n",
-             "GET_RANDOM");
+             "GET_REPLICATION");
 #endif
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# GET REPLICATION requests received"),
+                           1,
+                           GNUNET_NO);
   GNUNET_SERVER_client_keep (client);
-  plugin->api->iter_migration_order (plugin->api->cls,
-                                    0,
-                                    &transmit_item,
-                                    client);  
+  plugin->api->get_replication (plugin->api->cls,
+                               &transmit_item,
+                               client);  
 }
 
 
 /**
- * Context for the 'remove_callback'.
+ * Handle GET_ZERO_ANONYMITY-message.
+ *
+ * @param cls closure
+ * @param client identification of the client
+ * @param message the actual message
  */
-struct RemoveContext 
+static void
+handle_get_zero_anonymity (void *cls,
+                          struct GNUNET_SERVER_Client *client,
+                          const struct GNUNET_MessageHeader *message)
 {
-  /**
-   * Client for whom we're doing the remvoing.
-   */
-  struct GNUNET_SERVER_Client *client;
+  const struct GetZeroAnonymityMessage * msg = (const struct GetZeroAnonymityMessage*) message;
+  enum GNUNET_BLOCK_Type type;
 
-  /**
-   * GNUNET_YES if we managed to remove something.
-   */
-  int found;
-};
+  type = (enum GNUNET_BLOCK_Type) ntohl (msg->type);
+  if (type == GNUNET_BLOCK_TYPE_ANY)
+    {
+      GNUNET_break (0);
+      GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+      return;
+    }
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Processing `%s' request\n",
+             "GET_ZERO_ANONYMITY");
+#endif
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# GET ZERO ANONYMITY requests received"),
+                           1,
+                           GNUNET_NO);
+  GNUNET_SERVER_client_keep (client);
+  plugin->api->get_zero_anonymity (plugin->api->cls,
+                                  GNUNET_ntohll (msg->offset),
+                                  type,
+                                  &transmit_item,
+                                  client);  
+}
 
 
 /**
@@ -713,17 +1237,16 @@ struct RemoveContext
  */
 static int
 remove_callback (void *cls,
-                void *next_cls,
                 const GNUNET_HashCode * key,
                 uint32_t size,
                 const void *data,
-                uint32_t type,
+                enum GNUNET_BLOCK_Type type,
                 uint32_t priority,
                 uint32_t anonymity,
                 struct GNUNET_TIME_Absolute
                 expiration, uint64_t uid)
 {
-  struct RemoveContext *rc = cls;
+  struct GNUNET_SERVER_Client *client = cls;
 
   if (key == NULL)
     {
@@ -732,24 +1255,26 @@ remove_callback (void *cls,
                  "No further matches for `%s' request.\n",
                  "REMOVE");
 #endif 
-      if (GNUNET_YES == rc->found)
-       transmit_status (rc->client, GNUNET_OK, NULL);       
-      else
-       transmit_status (rc->client, GNUNET_SYSERR, _("Content not found"));            
-      GNUNET_SERVER_client_drop (rc->client);
-      GNUNET_free (rc);
+      transmit_status (client, GNUNET_NO, _("Content not found"));             
+      GNUNET_SERVER_client_drop (client);
       return GNUNET_OK; /* last item */
     }
-  rc->found = GNUNET_YES;
 #if DEBUG_DATASTORE
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Item %llu matches `%s' request.\n",
+             "Item %llu matches `%s' request for key `%s' and type %u.\n",
              (unsigned long long) uid,
-             "REMOVE");
+             "REMOVE",
+             GNUNET_h2s (key),
+             type);
 #endif 
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# bytes removed (explicit request)"),
+                           size,
+                           GNUNET_YES);
   GNUNET_CONTAINER_bloomfilter_remove (filter,
                                       key);
-  plugin->api->next_request (next_cls, GNUNET_YES);
+  transmit_status (client, GNUNET_OK, NULL);       
+  GNUNET_SERVER_client_drop (client);
   return GNUNET_NO;
 }
 
@@ -763,37 +1288,40 @@ remove_callback (void *cls,
  */
 static void
 handle_remove (void *cls,
-            struct GNUNET_SERVER_Client *client,
-            const struct GNUNET_MessageHeader *message)
+              struct GNUNET_SERVER_Client *client,
+              const struct GNUNET_MessageHeader *message)
 {
   const struct DataMessage *dm = check_data (message);
   GNUNET_HashCode vhash;
-  struct RemoveContext *rc;
 
-#if DEBUG_DATASTORE
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Processing `%s' request\n",
-             "REMOVE");
-#endif
   if (dm == NULL)
     {
       GNUNET_break (0);
       GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
       return;
     }
-  rc = GNUNET_malloc (sizeof(struct RemoveContext));
+#if DEBUG_DATASTORE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Processing `%s' request for `%s' of type %u\n",
+             "REMOVE",
+             GNUNET_h2s (&dm->key),
+             ntohl (dm->type));
+#endif
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# REMOVE requests received"),
+                           1,
+                           GNUNET_NO);
   GNUNET_SERVER_client_keep (client);
-  rc->client = client;
   GNUNET_CRYPTO_hash (&dm[1],
                      ntohl(dm->size),
                      &vhash);
-  GNUNET_SERVER_client_keep (client);
-  plugin->api->get (plugin->api->cls,
-                   &dm->key,
-                   &vhash,
-                   ntohl(dm->type),
-                   &remove_callback,
-                   rc);
+  plugin->api->get_key (plugin->api->cls,
+                       0,
+                       &dm->key,
+                       &vhash,
+                       (enum GNUNET_BLOCK_Type) ntohl(dm->type),
+                       &remove_callback,
+                       client);
 }
 
 
@@ -820,34 +1348,82 @@ handle_drop (void *cls,
 
 
 /**
- * List of handlers for the messages understood by this
- * service.
+ * Function called by plugins to notify us about a
+ * change in their disk utilization.
+ *
+ * @param cls closure (NULL)
+ * @param delta change in disk utilization, 
+ *        0 for "reset to empty"
  */
-static struct GNUNET_SERVER_MessageHandler handlers[] = {
-  {&handle_reserve, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_RESERVE, 
-   sizeof(struct ReserveMessage) }, 
-  {&handle_release_reserve, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_RELEASE_RESERVE, 
-   sizeof(struct ReleaseReserveMessage) }, 
-  {&handle_put, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_PUT, 0 }, 
-  {&handle_update, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_UPDATE, 
-   sizeof (struct UpdateMessage) }, 
-  {&handle_get, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_GET, 0 }, 
-  {&handle_get_random, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_GET_RANDOM, 
-   sizeof(struct GNUNET_MessageHeader) }, 
-  {&handle_remove, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_REMOVE, 0 }, 
-  {&handle_drop, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_DROP, 
-   sizeof(struct GNUNET_MessageHeader) }, 
-  {NULL, NULL, 0, 0}
-};
+static void
+disk_utilization_change_cb (void *cls,
+                           int delta)
+{
+  if ( (delta < 0) &&
+       (payload < -delta) )
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                 _("Datastore payload inaccurate (%lld < %lld).  Trying to fix.\n"),
+                 (long long) payload,
+                 (long long) -delta);
+      payload = plugin->api->estimate_size (plugin->api->cls);
+      sync_stats ();
+      return;
+    }
+  payload += delta;
+  lastSync++;
+  if (lastSync >= MAX_STAT_SYNC_LAG)
+    sync_stats ();
+}
 
 
+/**
+ * Callback function to process statistic values.
+ *
+ * @param cls closure (struct Plugin*)
+ * @param subsystem name of subsystem that created the statistic
+ * @param name the name of the datum
+ * @param value the current value
+ * @param is_persistent GNUNET_YES if the value is persistent, GNUNET_NO if not
+ * @return GNUNET_OK to continue, GNUNET_SYSERR to abort iteration
+ */
+static int
+process_stat_in (void *cls,
+                const char *subsystem,
+                const char *name,
+                uint64_t value,
+                int is_persistent)
+{
+  GNUNET_assert (stats_worked == GNUNET_NO);
+  stats_worked = GNUNET_YES;
+  payload += value;
+#if DEBUG_SQLITE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Notification from statistics about existing payload (%llu), new payload is %llu\n",
+             abs_value,
+             payload);
+#endif
+  return GNUNET_OK;
+}
+
+
+static void
+process_stat_done (void *cls,
+                  int success)
+{
+  struct DatastorePlugin *plugin = cls;
+
+  stat_get = NULL;
+  if (stats_worked == GNUNET_NO) 
+    payload = plugin->api->estimate_size (plugin->api->cls);
+}
+
 
 /**
  * Load the datastore plugin.
  */
 static struct DatastorePlugin *
-load_plugin (struct GNUNET_CONFIGURATION_Handle *cfg,
-            struct GNUNET_SCHEDULER_Handle *sched)
+load_plugin () 
 {
   struct DatastorePlugin *ret;
   char *libname;
@@ -865,7 +1441,8 @@ load_plugin (struct GNUNET_CONFIGURATION_Handle *cfg,
     }
   ret = GNUNET_malloc (sizeof(struct DatastorePlugin));
   ret->env.cfg = cfg;
-  ret->env.sched = sched;  
+  ret->env.duc = &disk_utilization_change_cb;
+  ret->env.cls = NULL;
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               _("Loading `%s' datastore plugin\n"), name);
   GNUNET_asprintf (&libname, "libgnunet_plugin_datastore_%s", name);
@@ -906,14 +1483,67 @@ unload_plugin (struct DatastorePlugin *plug)
 
 
 /**
- * Last task run during shutdown.  Disconnects us from
- * the transport and core.
+ * Final task run after shutdown.  Unloads plugins and disconnects us from
+ * statistics.
  */
 static void
-cleaning_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+unload_task (void *cls,
+            const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   unload_plugin (plugin);
   plugin = NULL;
+  if (filter != NULL)
+    {
+      GNUNET_CONTAINER_bloomfilter_free (filter);
+      filter = NULL;
+    }
+  if (lastSync > 0)
+    sync_stats ();
+  if (stat_get != NULL)
+    {
+      GNUNET_STATISTICS_get_cancel (stat_get);
+      stat_get = NULL;
+    }
+  if (stats != NULL)
+    {
+      GNUNET_STATISTICS_destroy (stats, GNUNET_YES);
+      stats = NULL;
+    }
+}
+
+
+/**
+ * Last task run during shutdown.  Disconnects us from
+ * the transport and core.
+ */
+static void
+cleaning_task (void *cls,
+              const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct TransmitCallbackContext *tcc;
+
+  cleaning_done = GNUNET_YES;
+  while (NULL != (tcc = tcc_head))
+    {
+      GNUNET_CONTAINER_DLL_remove (tcc_head,
+                                  tcc_tail,
+                                  tcc);
+      if (tcc->th != NULL)
+       {
+         GNUNET_CONNECTION_notify_transmit_ready_cancel (tcc->th);
+         GNUNET_SERVER_client_drop (tcc->client);
+       }
+      GNUNET_free (tcc->msg);
+      GNUNET_free (tcc);
+    }
+  if (expired_kill_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (expired_kill_task);
+      expired_kill_task = GNUNET_SCHEDULER_NO_TASK;
+    }
+  GNUNET_SCHEDULER_add_continuation (&unload_task,
+                                    NULL,
+                                    GNUNET_SCHEDULER_REASON_PREREQ_DONE);
 }
 
 
@@ -927,10 +1557,38 @@ cleaning_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  */
 static void
 cleanup_reservations (void *cls,
-                     struct GNUNET_SERVER_Client
-                     * client)
+                     struct GNUNET_SERVER_Client *client)
 {
-  /* FIXME */
+  struct ReservationList *pos;
+  struct ReservationList *prev;
+  struct ReservationList *next;
+
+  if (client == NULL)
+    return;
+  prev = NULL;
+  pos = reservations;
+  while (NULL != pos)
+    {
+      next = pos->next;
+      if (pos->client == client)
+       {
+         if (prev == NULL)
+           reservations = next;
+         else
+           prev->next = next;
+         reserved -= pos->amount + pos->entries * GNUNET_DATASTORE_ENTRY_OVERHEAD;
+         GNUNET_free (pos);
+       }
+      else
+       {
+         prev = pos;
+       }
+      pos = next;
+    }
+  GNUNET_STATISTICS_set (stats,
+                        gettext_noop ("# reserved"),
+                        reserved,
+                        GNUNET_NO);
 }
 
 
@@ -938,19 +1596,36 @@ cleanup_reservations (void *cls,
  * Process datastore requests.
  *
  * @param cls closure
- * @param sched scheduler to use
  * @param server the initialized server
- * @param cfg configuration to use
+ * @param c configuration to use
  */
 static void
 run (void *cls,
-     struct GNUNET_SCHEDULER_Handle *sched,
      struct GNUNET_SERVER_Handle *server,
-     struct GNUNET_CONFIGURATION_Handle *cfg)
+     const struct GNUNET_CONFIGURATION_Handle *c)
 {
+  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
+    {&handle_reserve, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_RESERVE, 
+     sizeof(struct ReserveMessage) }, 
+    {&handle_release_reserve, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_RELEASE_RESERVE, 
+     sizeof(struct ReleaseReserveMessage) }, 
+    {&handle_put, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_PUT, 0 }, 
+    {&handle_update, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_UPDATE, 
+     sizeof (struct UpdateMessage) }, 
+    {&handle_get, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_GET, 0 }, 
+    {&handle_get_replication, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_GET_REPLICATION, 
+     sizeof(struct GNUNET_MessageHeader) }, 
+    {&handle_get_zero_anonymity, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_GET_ZERO_ANONYMITY, 
+     sizeof(struct GetZeroAnonymityMessage) }, 
+    {&handle_remove, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_REMOVE, 0 }, 
+    {&handle_drop, NULL, GNUNET_MESSAGE_TYPE_DATASTORE_DROP, 
+     sizeof(struct GNUNET_MessageHeader) }, 
+    {NULL, NULL, 0, 0}
+  };
   char *fn;
   unsigned int bf_size;
 
+  cfg = c;
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_number (cfg,
                                              "DATASTORE", "QUOTA", &quota))
@@ -961,6 +1636,16 @@ run (void *cls,
                  "DATASTORE");
       return;
     }
+  stats = GNUNET_STATISTICS_create ("datastore", cfg);
+  GNUNET_STATISTICS_set (stats,
+                        gettext_noop ("# quota"),
+                        quota,
+                        GNUNET_NO);
+  cache_size = quota / 8; /* Or should we make this an option? */
+  GNUNET_STATISTICS_set (stats,
+                        gettext_noop ("# cache size"),
+                        cache_size,
+                        GNUNET_NO);
   bf_size = quota / 32; /* 8 bit per entry, 1 bit per 32 kb in DB */
   fn = NULL;
   if ( (GNUNET_OK !=
@@ -983,21 +1668,38 @@ run (void *cls,
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  _("Failed to initialize bloomfilter.\n"));
+      if (stats != NULL)
+       {
+         GNUNET_STATISTICS_destroy (stats, GNUNET_YES);
+         stats = NULL;
+       }
       return;
     }
-  plugin = load_plugin (cfg, sched);
+  plugin = load_plugin ();
   if (NULL == plugin)
     {
       GNUNET_CONTAINER_bloomfilter_free (filter);
+      filter = NULL;
+      if (stats != NULL)
+       {
+         GNUNET_STATISTICS_destroy (stats, GNUNET_YES);
+         stats = NULL;
+       }
       return;
     }
+  stat_get = GNUNET_STATISTICS_get (stats,
+                                   "datastore",
+                                   QUOTA_STAT_NAME,
+                                   GNUNET_TIME_UNIT_SECONDS,
+                                   &process_stat_done,
+                                   &process_stat_in,
+                                   plugin);
   GNUNET_SERVER_disconnect_notify (server, &cleanup_reservations, NULL);
   GNUNET_SERVER_add_handlers (server, handlers);
-  GNUNET_SCHEDULER_add_delayed (sched,
-                                GNUNET_YES,
-                                GNUNET_SCHEDULER_PRIORITY_IDLE,
-                                GNUNET_SCHEDULER_NO_PREREQUISITE_TASK,
-                                GNUNET_TIME_UNIT_FOREVER_REL,
+  expired_kill_task
+    = GNUNET_SCHEDULER_add_with_priority (GNUNET_SCHEDULER_PRIORITY_IDLE,
+                                         &delete_expired, NULL);
+  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
                                 &cleaning_task, NULL);
 }
 
@@ -1017,7 +1719,9 @@ main (int argc, char *const *argv)
   ret = (GNUNET_OK ==
          GNUNET_SERVICE_run (argc,
                              argv,
-                             "datastore", &run, NULL, NULL, NULL)) ? 0 : 1;
+                             "datastore",
+                            GNUNET_SERVICE_OPTION_NONE,
+                            &run, NULL)) ? 0 : 1;
   return ret;
 }