Index: src/btree.c
==================================================================
--- src/btree.c
+++ src/btree.c
@@ -4177,14 +4177,16 @@
         rc = SQLITE_CORRUPT_BKPT;
       }else{
         /* The current transaction allocated pages pMap->iFirst through
         ** nPage (inclusive) at the end of the database file. Meanwhile,
         ** other transactions have allocated (iFirst..nHPage). So move
-        ** pages (iFirst..MIN(nPage,nHPage)) to (MAX(nPage,nHPage)+1).  */
+        ** pages (iFirst..MIN(nPage,nHPage)) to (MAX(nPage,nHPage)+1). */
         Pgno iLast = MIN(nPage, nHPage);    /* Last page to move */
         Pgno nCurrent;                      /* Current size of db */
+
         nCurrent = MAX(nPage, nHPage);
+        pBt->nPage = nCurrent;
         rc = btreeRelocateRange(pBt, pMap->iFirst, iLast, &nCurrent);
 
         /* There are now no collisions with the snapshot at the head of the
         ** database file. So at this point it would be possible to write
         ** the transaction out to disk. Before doing so though, attempt to
@@ -6125,11 +6127,11 @@
   mxPage = btreePagecount(pBt);
   /* EVIDENCE-OF: R-05119-02637 The 4-byte big-endian integer at offset 36
   ** stores stores the total number of pages on the freelist. */
   n = get4byte(&pPage1->aData[36]);
   testcase( n==mxPage-1 );
-  if( ISCONCURRENT==0 && n>=mxPage ){
+  if( n>=mxPage ){
     return SQLITE_CORRUPT_BKPT;
   }
 
   /* Ensure page 1 is writable. This function will either change the number
   ** of pages in the free-list or the size of the database file. Since both

ADDED   test/concurrent6.test
Index: test/concurrent6.test
==================================================================
--- /dev/null
+++ test/concurrent6.test
@@ -0,0 +1,60 @@
+# 2017 May 26
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/wal_common.tcl
+set ::testprefix concurrent6
+
+ifcapable !concurrent {
+  finish_test
+  return
+}
+
+sqlite3 db2 test.db
+
+do_execsql_test 1.0 {
+  PRAGMA page_size = 1024;
+  PRAGMA journal_mode = wal;
+  CREATE TABLE t1(x);
+  CREATE TABLE t2(x);
+  CREATE TABLE t3(x);
+  CREATE TABLE t4(x);
+
+  INSERT INTO t1 VALUES(zeroblob(1500));
+} {wal}
+
+do_execsql_test -db db2 1.1 {
+  BEGIN CONCURRENT;
+    INSERT INTO t3 VALUES(zeroblob(4000));
+    DELETE FROM t1;
+}
+
+do_execsql_test 1.2 {
+  WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100) 
+  INSERT INTO t2 SELECT zeroblob(1000) FROM s;
+
+  WITH s(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100) 
+  INSERT INTO t4  SELECT zeroblob(1000) FROM s;
+
+  DELETE FROM t4;
+}
+
+do_execsql_test -db db2 1.3 {
+  COMMIT;
+}
+
+
+finish_test
+