1 files changed, 58 insertions, 16 deletions

diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index dc2ad6008b2d..4314f0d48d85 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 @@ repeat:
                 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 */