[t:4314], protect calling of cleaner_callback with fdlock

git-svn-id: file:///svn/toku/tokudb@38207 c7de825b-a66e-492c-adef-691d508d4ae1

newbrt/cachetable.c

@@ -3778,6 +3778,9 @@ toku_cleaner_thread (void *cachetable_v)
             cachetable_unlock(ct);
             break;
         }
+        // here we select a PAIR for cleaning
+        // look at some number of PAIRS, and 
+        // pick what we think is the best one for cleaning
         do {
             if (nb_mutex_users(&ct->cleaner_head->nb_mutex) > 0 || ct->cleaner_head->cachefile->is_flushing) {
                 goto next_pair;
@@ -3791,6 +3794,10 @@ toku_cleaner_thread (void *cachetable_v)
         next_pair:
             ct->cleaner_head = ct->cleaner_head->clock_next;
         } while (ct->cleaner_head != first_pair && n_seen < CLEANER_N_TO_CHECK);
+        //
+        // at this point, if we have found a PAIR for cleaning, 
+        // that is, best_pair != NULL, we do the clean
+        //
         if (best_pair) {
             nb_mutex_write_lock(&best_pair->nb_mutex, ct->mutex);
             // the order of operations for these two pieces is important
@@ -3807,38 +3814,56 @@ toku_cleaner_thread (void *cachetable_v)
             if (best_pair->checkpoint_pending) {
                 write_locked_pair_for_checkpoint(ct, best_pair);
             }
-        }
-        cachetable_unlock(ct);
-        if (best_pair) {
+
+            CACHEFILE cf = best_pair->cachefile;
+            BOOL cleaner_callback_called = FALSE;
+            // grab the fdlock, because the cleaner callback
+            // will access the fd.
+            rwlock_prefer_read_lock(&cf->fdlock, ct->mutex);
+            
             // it's theoretically possible that after writing a PAIR for checkpoint, the
             // PAIR's heuristic tells us nothing needs to be done. It is not possible
             // in Dr. Noga, but unit tests verify this behavior works properly.
-            CACHEFILE cf = best_pair->cachefile;
-            if (cleaner_thread_rate_pair(best_pair) > 0) {
+            // 
+            // also, because the cleaner thread needs to act as a client
+            // and honor the same invariants that client threads honor,
+            // we refuse to call the cleaner callback if the cachefile
+            // has been redirected to /dev/null, because client threads
+            // do not call APIs that access the file if the file has been
+            // redirected to /dev/null
+            if (!toku_cachefile_is_dev_null_unlocked(cf) && 
+                cleaner_thread_rate_pair(best_pair) > 0) 
+            {
+                cachetable_unlock(ct);
                 int r = best_pair->cleaner_callback(best_pair->value,
                                                     best_pair->key,
                                                     best_pair->fullhash,
                                                     best_pair->write_extraargs);
                 assert_zero(r);
-                // The cleaner callback must have unlocked the pair, so we
-                // don't need to unlock it here.
-            }
-            else {
+                cleaner_callback_called = TRUE;
                 cachetable_lock(ct);
+            }
+
+            // The cleaner callback must have unlocked the pair, so we
+            // don't need to unlock it if the cleaner callback is called.
+            if (!cleaner_callback_called) {
                 nb_mutex_write_unlock(&best_pair->nb_mutex);
-                cachetable_unlock(ct);
             }
+            rwlock_read_unlock(&cf->fdlock);
             // We need to make sure the cachefile sticks around so a close
             // can't come destroy it.  That's the purpose of this
             // "add/remove_background_job" business, which means the
             // cachefile is still valid here, even though the cleaner
-            // callback unlocks the pair.            
-            remove_background_job(cf, false);
-        } else {
+            // callback unlocks the pair. 
+            remove_background_job(cf, true);
+            cachetable_unlock(ct);
+        }
+        else {
+            cachetable_unlock(ct);
             // If we didn't find anything this time around the cachetable,
             // we probably won't find anything if we run around again, so
-            // just break out now and we'll try again when the cleaner
-            // thread runs again.
+            // just break out from the for-loop now and 
+            // we'll try again when the cleaner thread runs again.
             break;
         }
     }

newbrt/tests/cachetable-cleaner-dev-null.c

+#ident "$Id: cachetable-simple-verify.c 36689 2011-11-07 22:08:05Z zardosht $"
+#ident "Copyright (c) 2007-2011 Tokutek Inc.  All rights reserved."
+#include "includes.h"
+#include "test.h"
+
+CACHEFILE f1;
+
+
+static void
+flush (CACHEFILE f __attribute__((__unused__)),
+       int UU(fd),
+       CACHEKEY k  __attribute__((__unused__)),
+       void *v     __attribute__((__unused__)),
+       void *e     __attribute__((__unused__)),
+       PAIR_ATTR s      __attribute__((__unused__)),
+       PAIR_ATTR* new_size      __attribute__((__unused__)),
+       BOOL w      __attribute__((__unused__)),
+       BOOL keep   __attribute__((__unused__)),
+       BOOL c      __attribute__((__unused__))
+       ) {
+  /* Do nothing */
+  if (verbose) { printf("FLUSH: %d\n", (int)k.b); }
+  //usleep (5*1024*1024);
+  PAIR_ATTR attr = make_pair_attr(8);
+  attr.cache_pressure_size = 8;
+  *new_size = attr;
+  if (w) {
+      assert(c);
+  }
+}
+
+static int
+fetch (CACHEFILE f        __attribute__((__unused__)),
+       int UU(fd),
+       CACHEKEY k         __attribute__((__unused__)),
+       u_int32_t fullhash __attribute__((__unused__)),
+       void **value       __attribute__((__unused__)),
+       PAIR_ATTR *sizep        __attribute__((__unused__)),
+       int  *dirtyp,
+       void *extraargs    __attribute__((__unused__))
+       ) {
+  *dirtyp = 0;
+  *value = NULL;
+  *sizep = make_pair_attr(8);
+  return 0;
+}
+
+static int
+cleaner_callback(
+    void* UU(brtnode_pv),
+    BLOCKNUM UU(blocknum),
+    u_int32_t UU(fullhash),
+    void* UU(extraargs)
+    )
+{
+    assert(FALSE);
+    return 0;
+}
+
+
+static void
+cachetable_test (void) {
+  const int test_limit = 12;
+  int r;
+  CACHETABLE ct;
+  r = toku_create_cachetable(&ct, test_limit, ZERO_LSN, NULL_LOGGER); assert(r == 0);
+  char fname1[] = __FILE__ "test1.dat";
+  unlink(fname1);
+  r = toku_cachetable_openf(&f1, ct, fname1, O_RDWR|O_CREAT, S_IRWXU|S_IRWXG|S_IRWXO); assert(r == 0);
+
+  void* v1;
+  //void* v2;
+  long s1;
+  //long s2;
+  r = toku_cachetable_get_and_pin(f1, make_blocknum(1), 1, &v1, &s1, flush, fetch, def_pe_est_callback, def_pe_callback, def_pf_req_callback, def_pf_callback, cleaner_callback, NULL, NULL);
+  PAIR_ATTR attr = make_pair_attr(8);
+  attr.cache_pressure_size = 8;
+  r = toku_cachetable_unpin(f1, make_blocknum(1), 1, CACHETABLE_DIRTY, attr);
+
+  // test that once we have redirected to /dev/null,
+  // cleaner callback is NOT called
+  r = toku_cachefile_redirect_nullfd(f1);
+  assert_zero(r);
+
+  toku_cleaner_thread(ct);
+
+  toku_cachetable_verify(ct);
+  r = toku_cachefile_close(&f1, 0, FALSE, ZERO_LSN); assert(r == 0 && f1 == 0);
+  r = toku_cachetable_close(&ct); lazy_assert_zero(r);
+}
+
+int
+test_main(int argc, const char *argv[]) {
+  default_parse_args(argc, argv);
+  cachetable_test();
+  return 0;
+}