GFS2: Allow caching of glocks for flock

Hi,

This patch removes the GLF_NOCACHE flag from the glocks associated with flocks. There should be no good reason not to cache glocks for flocks:
they only force the glock to be demoted before they can be reacquired, which can slow down performance and even cause glock hangs, especially in cases where the flocks are held in Shared (SH) mode.

Regards,

Bob Peterson
Red Hat File Systems

---

index 4fc3a30..0740a57 100644
@@ -981,7 +981,7 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl)
 	int error = 0;
 
 	state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED;
-	flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY) | GL_EXACT | GL_NOCACHE;
+	flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY) | GL_EXACT;
 
 	mutex_lock(&fp->f_fl_mutex);