Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
[linux-3.10.git] / fs / dlm / ast.c
index 30c11f3..4314f0d 100644 (file)
@@ -2,7 +2,7 @@
 *******************************************************************************
 **
 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
-**  Copyright (C) 2004-2005 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)
+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);
+               dlm_user_add_ast(lkb, type, mode);
                return;
        }
 
@@ -44,8 +44,21 @@ void dlm_add_ast(struct dlm_lkb *lkb, int type)
        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 (type == AST_BAST)
+               lkb->lkb_bastmode = mode;
+       else
+               lkb->lkb_castmode = mode;
        spin_unlock(&ast_queue_lock);
 
        set_bit(WAKE_ASTS, &astd_wakeflags);
@@ -57,52 +70,73 @@ 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, found, bmode;
-
-       for (;;) {
-               found = 0;
-               spin_lock(&ast_queue_lock);
-               list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
-                       r = lkb->lkb_resource;
-                       ls = r->res_ls;
-
-                       if (dlm_locking_stopped(ls))
-                               continue;
-
-                       list_del(&lkb->lkb_astqueue);
-                       type = lkb->lkb_ast_type;
-                       lkb->lkb_ast_type = 0;
-                       found = 1;
-                       break;
-               }
+       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);
+       list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
+               r = lkb->lkb_resource;
+               ls = r->res_ls;
+
+               if (dlm_locking_stopped(ls))
+                       continue;
+
+               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);
 
-               if (!found)
-                       break;
+               do_cast = (type & AST_COMP) && castfn;
+               do_bast = (type & AST_BAST) && bastfn;
 
-               cast = lkb->lkb_astfn;
-               bast = lkb->lkb_bastfn;
-               bmode = lkb->lkb_bastmode;
+               /* Skip a bast if its blocking mode is compatible with the
+                  granted mode of the preceding cast. */
 
-               if ((type & AST_COMP) && cast)
-                       cast(lkb->lkb_astparam);
+               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;
+               }
 
-               /* FIXME: Is it safe to look at lkb_grmode here
-                  without doing a lock_rsb() ?
-                  Look at other checks in v1 to avoid basts. */
+               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 ((type & AST_BAST) && bast)
-                       if (!dlm_modes_compat(lkb->lkb_grmode, bmode))
-                               bast(lkb->lkb_astparam, bmode);
+               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 */
                dlm_put_lkb(lkb);
 
                cond_resched();
+               goto repeat;
        }
+       spin_unlock(&ast_queue_lock);
 }
 
 static inline int no_asts(void)