fsyncLock and Unlock are stackable!!

capture.txt

mongo localhost:27018
MongoDB shell version: 2.4.3
connecting to: localhost:27018/test
dev-mcs-01:SECONDARY> serverIsLocked = function () {
...                      var co = db.currentOp();
...                      if (co && co.fsyncLock) {
...                          return true;
...                      }
...                      return false;
...                  }
function () {
                     var co = db.currentOp();
                     if (co && co.fsyncLock) {
                         return true;
                     }
                     return false;
                 }
dev-mcs-01:SECONDARY> serverIsLocked()
false  <---- the server reports not locked
dev-mcs-01:SECONDARY> db.fsyncLock()
{
  "info" : "now locked against writes, use db.fsyncUnlock() to unlock",
	"seeAlso" : "http://dochub.mongodb.org/core/fsynccommand",
	"ok" : 1
}
dev-mcs-01:SECONDARY> serverIsLocked()
true <---- server is now LOCKED
dev-mcs-01:SECONDARY> db.fsyncUnlock()
{ "ok" : 1, "info" : "unlock completed" }
dev-mcs-01:SECONDARY> serverIsLocked()
false <---- server is UNLOCKED, all cool.
dev-mcs-01:SECONDARY> db.fsyncLock()
{
	"info" : "now locked against writes, use db.fsyncUnlock() to unlock",
	"seeAlso" : "http://dochub.mongodb.org/core/fsynccommand",
	"ok" : 1
} <---- one lock
dev-mcs-01:SECONDARY> db.fsyncLock()
{
	"info" : "now locked against writes, use db.fsyncUnlock() to unlock",
	"seeAlso" : "http://dochub.mongodb.org/core/fsynccommand",
	"ok" : 1
} <---- two locks
dev-mcs-01:SECONDARY> db.fsyncLock()
{
	"info" : "now locked against writes, use db.fsyncUnlock() to unlock",
	"seeAlso" : "http://dochub.mongodb.org/core/fsynccommand",
	"ok" : 1
} <---- three locks
dev-mcs-01:SECONDARY> serverIsLocked()
true <---- server is locked, cool!!!
dev-mcs-01:SECONDARY> db.fsyncUnlock()
{ "ok" : 1, "info" : "unlock completed" }
dev-mcs-01:SECONDARY> serverIsLocked()
true <---- NOT COOL, fsyncUnlock() reports "unlock completed" and "ok" : 1 but not unlocked!!!!
dev-mcs-01:SECONDARY> db.fsyncUnlock()
{ "ok" : 1, "info" : "unlock completed" }
dev-mcs-01:SECONDARY> serverIsLocked()
true <---- NOT COOL, fsyncUnlock() reports "unlock completed" and "ok" : 1 but not unlocked!!!!
dev-mcs-01:SECONDARY> db.fsyncUnlock()
{ "ok" : 1, "info" : "unlock completed" }
dev-mcs-01:SECONDARY> serverIsLocked()
false <---- 3 locks need 3 unlocks!!!!!! NOT MENTIONED ANYWHERE!!!!!!
dev-mcs-01:SECONDARY> db.fsyncUnlock()
{ "ok" : 0, "errmsg" : "not locked" }
dev-mcs-01:SECONDARY>