SERVER-4328 add Command::localGlobally method

8 files changed, 33 insertions, 4 deletions

diff --git a/src/mongo/db/cloner.cpp b/src/mongo/db/cloner.cpp
index a417cfef8ac..171a634a11b 100644
--- a/src/mongo/db/cloner.cpp
+++ b/src/mongo/db/cloner.cpp
@@ -540,6 +540,7 @@ namespace mongo {
     } cmdclonecollection;
 
 
+    // SERVER-4328 todo review for concurrency
     thread_specific_ptr< DBClientConnection > authConn_;
     /* Usage:
      admindb.$cmd.findOne( { copydbgetnonce: 1, fromhost: <hostname> } );
@@ -603,6 +604,9 @@ namespace mongo {
             bool slaveOk = cmdObj["slaveOk"].trueValue();
             string fromhost = cmdObj.getStringField("fromhost");
             if ( fromhost.empty() ) {
+                // SERVER-4328 TODO local globally in this case?  or just lock the two databases, but need to lock them in a well-defined order perhaps, 
+                //                  and the d_concurrency code doesn't allow that yet.
+
                 /* copy from self */
                 stringstream ss;
                 ss << "localhost:" << cmdLine.port;
diff --git a/src/mongo/db/commands.cpp b/src/mongo/db/commands.cpp
index cbe9ffc6861..3da942d8c24 100755
--- a/src/mongo/db/commands.cpp
+++ b/src/mongo/db/commands.cpp
@@ -74,6 +74,8 @@ namespace mongo {
             ss << "S ";

         if( adminOnly() )

             ss << "A";

+        if( lockGlobally() ) 

+            ss << " lockGlobally ";

         ss << "</td>";

         ss << "<td>";

         if( helpStr != "no help defined" ) {

diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index 8d8ee7545f0..d03b792cedf 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -37,7 +37,9 @@ namespace mongo {
         // only makes sense for commands where 1st parm is the collection.
         virtual string parseNs(const string& dbname, const BSONObj& cmdObj) const;
 
-        enum LockType { READ = -1 , NONE = 0 , WRITE = 1, GLOBAL = 2 };
+        // warning: isAuthorized uses the lockType() return values, and values are being passed 
+        // around as ints so be careful as it isn't really typesafe and will need cleanup later
+        enum LockType { READ = -1 , NONE = 0 , WRITE = 1 };
 
         const string name;
 
@@ -52,12 +54,17 @@ namespace mongo {
         virtual bool run(const string& db, BSONObj& cmdObj, int options, string& errmsg, BSONObjBuilder& result, bool fromRepl = false ) = 0;
 
         /*
-           note: logTheTop() MUST be false if READ
+           note: logTheOp() MUST be false if READ
            if NONE, can't use Client::Context setup
                     use with caution
          */
         virtual LockType locktype() const = 0;
 
+        /** if true, lock globally instead of just the one database. by default only the one 
+            database will be locked. 
+        */
+        virtual bool lockGlobally() const { return false; }
+
         /* Return true if only the admin ns has privileges to run this command. */
         virtual bool adminOnly() const {
             return false;
diff --git a/src/mongo/db/d_concurrency.cpp b/src/mongo/db/d_concurrency.cpp
index a0e874160c6..83612e56c76 100755
--- a/src/mongo/db/d_concurrency.cpp
+++ b/src/mongo/db/d_concurrency.cpp
@@ -625,12 +625,14 @@ namespace mongo {
     void MongoMutex::assertWriteLocked() const { 
         if( !isWriteLocked() ) { 
             lockState().dump();
+            dassert(false); // dassert will terminate buildbot
             msgasserted(0, "expected write lock");
         }
     }
     void MongoMutex::assertAtLeastReadLocked() const { 
         if( !atLeastReadLocked() ) { 
             lockState().dump();
+            dassert(false); // dassert will terminate buildbot
             msgasserted(0, "expected read lock");
         }
     }
diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index 3344814524e..f266b1243eb 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -330,6 +330,11 @@ namespace mongo {
         virtual bool slaveOk() const {
             return false;
         }
+
+        // this is suboptimal but syncDataAndTruncateJournal is called from dropDatabase, and that 
+        // may need a global lock.
+        virtual bool lockGlobally() const { return true; }
+
         virtual LockType locktype() const { return WRITE; }
         CmdDropDatabase() : Command("dropDatabase") {}
         bool run(const string& dbname, BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {
@@ -1051,6 +1056,7 @@ namespace mongo {
         virtual bool adminOnly() const { return true; }
         virtual bool slaveOk() const { return false; }
         virtual LockType locktype() const { return WRITE; }
+        virtual bool lockGlobally() const { return true; }
 
         CmdCloseAllDatabases() : Command( "closeAllDatabases" ) {}
         bool run(const string& dbname , BSONObj& jsobj, int, string& errmsg, BSONObjBuilder& result, bool /*fromRepl*/) {
@@ -1864,6 +1870,8 @@ namespace mongo {
 
         bool retval = false;
         if ( c->locktype() == Command::NONE ) {
+            assert( !c->lockGlobally() );
+
             // we also trust that this won't crash
             retval = true;
 
@@ -1884,13 +1892,16 @@ namespace mongo {
             // read lock
             assert( ! c->logTheOp() );
             string ns = c->parseNs(dbname, cmdObj);
+            scoped_ptr<Lock::GlobalRead> lk;
+            if( c->lockGlobally() )
+                lk.reset( new Lock::GlobalRead() );
             Client::ReadContext ctx( ns , dbpath, c->requiresAuth() ); // read locks
             client.curop()->ensureStarted();
             retval = _execCommand(c, dbname , cmdObj , queryOptions, result , fromRepl );
         }
         else {
             dassert( c->locktype() == Command::WRITE );
-            writelock lk;
+            writelock lk( c->lockGlobally() ? "" : dbname );
             client.curop()->ensureStarted();
             Client::Context ctx( dbname , dbpath , c->requiresAuth() );
             retval = _execCommand(c, dbname , cmdObj , queryOptions, result , fromRepl );
diff --git a/src/mongo/db/dbeval.cpp b/src/mongo/db/dbeval.cpp
index 9e77d8c8097..67e110da71e 100644
--- a/src/mongo/db/dbeval.cpp
+++ b/src/mongo/db/dbeval.cpp
@@ -106,6 +106,7 @@ namespace mongo {
         return true;
     }
 
+    // SERVER-4328 todo review for concurrency
     class CmdEval : public Command {
     public:
         virtual bool slaveOk() const {
diff --git a/src/mongo/db/oplog.cpp b/src/mongo/db/oplog.cpp
index b3eeb06cf75..f220845d853 100644
--- a/src/mongo/db/oplog.cpp
+++ b/src/mongo/db/oplog.cpp
@@ -838,6 +838,7 @@ namespace mongo {
         return failedUpdate;
     }
 
+    // SERVER-4328 todo review for concurrency
     class ApplyOpsCmd : public Command {
     public:
         virtual bool slaveOk() const { return false; }
diff --git a/src/mongo/db/repl.cpp b/src/mongo/db/repl.cpp
index 5490515af6b..2f5bfde7dbe 100644
--- a/src/mongo/db/repl.cpp
+++ b/src/mongo/db/repl.cpp
@@ -88,7 +88,8 @@ namespace mongo {
             return true;
         }
         virtual bool logTheOp() { return false; }
-        virtual LockType locktype() const { return GLOBAL; }
+        virtual bool lockGlobally() const { return true; }
+        virtual LockType locktype() const { return WRITE; }
         void help(stringstream&h) const { h << "resync (from scratch) an out of date replica slave.\nhttp://www.mongodb.org/display/DOCS/Master+Slave"; }
         CmdResync() : Command("resync") { }
         virtual bool run(const string& , BSONObj& cmdObj, int, string& errmsg, BSONObjBuilder& result, bool fromRepl) {