fixed diskstore race condition

[redis.git] / src / dscache.c

diff --git a/src/dscache.c b/src/dscache.c
index a4d045e1d2c06e37ca1b03255ca08693e63f84a5..cbe9bb016cac41e8637d9c49ef512ad45aafe70d 100644 (file)
--- a/src/dscache.c
+++ b/src/dscache.c
@@ -212,7 +212,7 @@ int cacheFreeOneEntry(void) {
         }
     }
     if (best == NULL) {
-        /* Was not able to fix a single object... we should check if our
+        /* Not able to free a single object? we should check if our
          * IO queues have stuff in queue, and try to consume the queue
          * otherwise we'll use an infinite amount of memory if changes to
          * the dataset are faster than I/O */
@@ -240,13 +240,6 @@ int cacheFreeOneEntry(void) {
     return REDIS_OK;
 }
 
-/* Return true if it's safe to swap out objects in a given moment.
- * Basically we don't want to swap objects out while there is a BGSAVE
- * or a BGAEOREWRITE running in backgroud. */
-int dsCanTouchDiskStore(void) {
-    return (server.bgsavechildpid == -1 && server.bgrewritechildpid == -1);
-}
-
 /* ==================== Disk store negative caching  ========================
  *
  * When disk store is enabled, we need negative caching, that is, to remember
@@ -390,11 +383,10 @@ void vmThreadedIOCompletedJob(aeEventLoop *el, int fd, void *privdata,
             }
             cacheScheduleIODelFlag(j->db,j->key,REDIS_IO_LOADINPROG);
             handleClientsBlockedOnSwappedKey(j->db,j->key);
-            freeIOJob(j);
         } else if (j->type == REDIS_IOJOB_SAVE) {
             cacheScheduleIODelFlag(j->db,j->key,REDIS_IO_SAVEINPROG);
-            freeIOJob(j);
         }
+        freeIOJob(j);
         processed++;
         if (privdata == NULL) cacheScheduleIOPushJobs(0);
         if (processed == toprocess) return;
@@ -595,8 +587,6 @@ void queueIOJob(iojob *j) {
     redisLog(REDIS_DEBUG,"Queued IO Job %p type %d about key '%s'\n",
         (void*)j, j->type, (char*)j->key->ptr);
     listAddNodeTail(server.io_newjobs,j);
-    if (server.io_active_threads < server.vm_max_threads)
-        spawnIOThread();
 }
 
 /* Consume all the IO scheduled operations, and all the thread IO jobs
@@ -900,8 +890,16 @@ int waitForSwappedKey(redisClient *c, robj *key) {
     listAddNodeTail(l,c);
 
     /* Are we already loading the key from disk? If not create a job */
-    if (de == NULL)
-        cacheScheduleIO(c->db,key,REDIS_IO_LOAD);
+    if (de == NULL) {
+        int flags = cacheScheduleIOGetFlags(c->db,key);
+
+        /* It is possible that even if there are no clients waiting for
+         * a load operation, still we have a load operation in progress.
+         * For instance think to a client performing a GET and then
+         * closing the connection */
+        if ((flags & (REDIS_IO_LOAD|REDIS_IO_LOADINPROG)) == 0)
+            cacheScheduleIO(c->db,key,REDIS_IO_LOAD);
+    }
     return 1;
 }