diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index dc2ad6008b2d08a354ce23507c44febb121b6466..4314f0d48d85668e0d0af943cdb2b7d8fde4863a 100644
--- a/fs/dlm/ast.c
+++ b/fs/dlm/ast.c
@@ -2,7 +2,7 @@
 *******************************************************************************
 **
 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
-**  Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2004-2010 Red Hat, Inc.  All rights reserved.
 **
 **  This copyrighted material is made available to anyone wishing to use,
 **  modify, copy, or redistribute it subject to the terms and conditions
@@ -33,10 +33,10 @@ void dlm_del_ast(struct dlm_lkb *lkb)
 	spin_unlock(&ast_queue_lock);
 }
 
-void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
+void dlm_add_ast(struct dlm_lkb *lkb, int type, int mode)
 {
 	if (lkb->lkb_flags & DLM_IFL_USER) {
-		dlm_user_add_ast(lkb, type, bastmode);
+		dlm_user_add_ast(lkb, type, mode);
 		return;
 	}
 
@@ -44,10 +44,21 @@ void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
 	if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) {
 		kref_get(&lkb->lkb_ref);
 		list_add_tail(&lkb->lkb_astqueue, &ast_queue);
+		lkb->lkb_ast_first = type;
 	}
+
+	/* sanity check, this should not happen */
+
+	if ((type == AST_COMP) && (lkb->lkb_ast_type & AST_COMP))
+		log_print("repeat cast %d castmode %d lock %x %s",
+			  mode, lkb->lkb_castmode,
+			  lkb->lkb_id, lkb->lkb_resource->res_name);
+
 	lkb->lkb_ast_type |= type;
-	if (bastmode)
-		lkb->lkb_bastmode = bastmode;
+	if (type == AST_BAST)
+		lkb->lkb_bastmode = mode;
+	else
+		lkb->lkb_castmode = mode;
 	spin_unlock(&ast_queue_lock);
 
 	set_bit(WAKE_ASTS, &astd_wakeflags);
@@ -59,9 +70,9 @@ static void process_asts(void)
 	struct dlm_ls *ls = NULL;
 	struct dlm_rsb *r = NULL;
 	struct dlm_lkb *lkb;
-	void (*cast) (void *astparam);
-	void (*bast) (void *astparam, int mode);
-	int type = 0, bastmode;
+	void (*castfn) (void *astparam);
+	void (*bastfn) (void *astparam, int mode);
+	int type, first, bastmode, castmode, do_bast, do_cast, last_castmode;
 
 repeat:
 	spin_lock(&ast_queue_lock);
@@ -75,17 +86,48 @@ static void process_asts(void)
 		list_del(&lkb->lkb_astqueue);
 		type = lkb->lkb_ast_type;
 		lkb->lkb_ast_type = 0;
+		first = lkb->lkb_ast_first;
+		lkb->lkb_ast_first = 0;
 		bastmode = lkb->lkb_bastmode;
-
+		castmode = lkb->lkb_castmode;
+		castfn = lkb->lkb_astfn;
+		bastfn = lkb->lkb_bastfn;
 		spin_unlock(&ast_queue_lock);
-		cast = lkb->lkb_astfn;
-		bast = lkb->lkb_bastfn;
-
-		if ((type & AST_COMP) && cast)
-			cast(lkb->lkb_astparam);
 
-		if ((type & AST_BAST) && bast)
-			bast(lkb->lkb_astparam, bastmode);
+		do_cast = (type & AST_COMP) && castfn;
+		do_bast = (type & AST_BAST) && bastfn;
+
+		/* Skip a bast if its blocking mode is compatible with the
+		   granted mode of the preceding cast. */
+
+		if (do_bast) {
+			if (first == AST_COMP)
+				last_castmode = castmode;
+			else
+				last_castmode = lkb->lkb_castmode_done;
+			if (dlm_modes_compat(bastmode, last_castmode))
+				do_bast = 0;
+		}
+
+		if (first == AST_COMP) {
+			if (do_cast)
+				castfn(lkb->lkb_astparam);
+			if (do_bast)
+				bastfn(lkb->lkb_astparam, bastmode);
+		} else if (first == AST_BAST) {
+			if (do_bast)
+				bastfn(lkb->lkb_astparam, bastmode);
+			if (do_cast)
+				castfn(lkb->lkb_astparam);
+		} else {
+			log_error(ls, "bad ast_first %d ast_type %d",
+				  first, type);
+		}
+
+		if (do_cast)
+			lkb->lkb_castmode_done = castmode;
+		if (do_bast)
+			lkb->lkb_bastmode_done = bastmode;
 
 		/* this removes the reference added by dlm_add_ast
 		   and may result in the lkb being freed */
diff --git a/fs/dlm/ast.h b/fs/dlm/ast.h
index 1b5fc5f428fdd2d0dc01050be27de84c65a2b659..bcb1aaba519d97c031b06b356e7aa9051a7ecb76 100644
--- a/fs/dlm/ast.h
+++ b/fs/dlm/ast.h
@@ -1,7 +1,7 @@
 /******************************************************************************
 *******************************************************************************
 **
-**  Copyright (C) 2005-2008 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2005-2010 Red Hat, Inc.  All rights reserved.
 **
 **  This copyrighted material is made available to anyone wishing to use,
 **  modify, copy, or redistribute it subject to the terms and conditions
@@ -13,7 +13,7 @@
 #ifndef __ASTD_DOT_H__
 #define __ASTD_DOT_H__
 
-void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode);
+void dlm_add_ast(struct dlm_lkb *lkb, int type, int mode);
 void dlm_del_ast(struct dlm_lkb *lkb);
 
 void dlm_astd_wake(void);
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 826d3dc6e0ab50db977500844ddc62cdcede83ad..f632b58cd2221c71fd7c6454cf70f9d17dfa7e1e 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -2,7 +2,7 @@
 *******************************************************************************
 **
 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
-**  Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2004-2010 Red Hat, Inc.  All rights reserved.
 **
 **  This copyrighted material is made available to anyone wishing to use,
 **  modify, copy, or redistribute it subject to the terms and conditions
@@ -232,11 +232,17 @@ struct dlm_lkb {
 	int8_t			lkb_status;     /* granted, waiting, convert */
 	int8_t			lkb_rqmode;	/* requested lock mode */
 	int8_t			lkb_grmode;	/* granted lock mode */
-	int8_t			lkb_bastmode;	/* requested mode */
 	int8_t			lkb_highbast;	/* highest mode bast sent for */
+
 	int8_t			lkb_wait_type;	/* type of reply waiting for */
 	int8_t			lkb_wait_count;
 	int8_t			lkb_ast_type;	/* type of ast queued for */
+	int8_t			lkb_ast_first;	/* type of first ast queued */
+
+	int8_t			lkb_bastmode;	/* req mode of queued bast */
+	int8_t			lkb_castmode;	/* gr mode of queued cast */
+	int8_t			lkb_bastmode_done; /* last delivered bastmode */
+	int8_t			lkb_castmode_done; /* last delivered castmode */
 
 	struct list_head	lkb_idtbl_list;	/* lockspace lkbtbl */
 	struct list_head	lkb_statequeue;	/* rsb g/c/w list */
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 9c0c1db1e10534aa2a44b9634ff9790859d542cc..e08ea93432bce95af28aea73b1d39cdb9062e7da 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1,7 +1,7 @@
 /******************************************************************************
 *******************************************************************************
 **
-**  Copyright (C) 2005-2008 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2005-2010 Red Hat, Inc.  All rights reserved.
 **
 **  This copyrighted material is made available to anyone wishing to use,
 **  modify, copy, or redistribute it subject to the terms and conditions
@@ -307,7 +307,7 @@ static void queue_cast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rv)
 	lkb->lkb_lksb->sb_status = rv;
 	lkb->lkb_lksb->sb_flags = lkb->lkb_sbflags;
 
-	dlm_add_ast(lkb, AST_COMP, 0);
+	dlm_add_ast(lkb, AST_COMP, lkb->lkb_grmode);
 }
 
 static inline void queue_cast_overlap(struct dlm_rsb *r, struct dlm_lkb *lkb)
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index e73a4bb572aa2de896c3e493bf7545f8f2358434..a4bfd31ac45bec4ad5e1010e0ad6a386a338f18b 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2009 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006-2010 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -173,7 +173,7 @@ static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
 /* we could possibly check if the cancel of an orphan has resulted in the lkb
    being removed and then remove that lkb from the orphans list and free it */
 
-void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
+void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int mode)
 {
 	struct dlm_ls *ls;
 	struct dlm_user_args *ua;
@@ -206,8 +206,10 @@ void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
 
 	ast_type = lkb->lkb_ast_type;
 	lkb->lkb_ast_type |= type;
-	if (bastmode)
-		lkb->lkb_bastmode = bastmode;
+	if (type == AST_BAST)
+		lkb->lkb_bastmode = mode;
+	else
+		lkb->lkb_castmode = mode;
 
 	if (!ast_type) {
 		kref_get(&lkb->lkb_ref);
diff --git a/fs/dlm/user.h b/fs/dlm/user.h
index 1c96864922869b396bcbf2cab5a70c2eb32c064b..f196091dd7ff8d31c687526d973c404d30098f00 100644
--- a/fs/dlm/user.h
+++ b/fs/dlm/user.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2008 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2006-2010 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -9,7 +9,7 @@
 #ifndef __USER_DOT_H__
 #define __USER_DOT_H__
 
-void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode);
+void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int mode);
 int dlm_user_init(void);
 void dlm_user_exit(void);
 int dlm_device_deregister(struct dlm_ls *ls);