dlm: improve how bast mode handling

The lkb bastmode value is set in the context of processing the
lock, and read by the dlm_astd thread.  Because it's accessed
in these two separate contexts, the writing/reading ought to
be done under a lock.  This is simple to do by setting it and
reading it when the lkb is added to and removed from dlm_astd's
callback list which is properly locked.

Signed-off-by: David Teigland <teigland@redhat.com>

5 files changed, 17 insertions, 15 deletions

diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index 09b167df790e..fbe840d09493 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) 2004-2005 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2004-2008 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 bastmode)
 {
         if (lkb->lkb_flags & DLM_IFL_USER) {
-                dlm_user_add_ast(lkb, type);
+                dlm_user_add_ast(lkb, type, bastmode);
                 return;
         }
 
@@ -46,6 +46,8 @@ void dlm_add_ast(struct dlm_lkb *lkb, int type)
                 list_add_tail(&lkb->lkb_astqueue, &ast_queue);
         }
         lkb->lkb_ast_type |= type;
+        if (bastmode)
+                lkb->lkb_bastmode = bastmode;
         spin_unlock(&ast_queue_lock);
 
         set_bit(WAKE_ASTS, &astd_wakeflags);
@@ -59,7 +61,7 @@ static void process_asts(void)
         struct dlm_lkb *lkb;
         void (*cast) (void *astparam);
         void (*bast) (void *astparam, int mode);
-        int type = 0, found, bmode;
+        int type = 0, found, bastmode;
 
         for (;;) {
                 found = 0;
@@ -74,6 +76,7 @@ static void process_asts(void)
                         list_del(&lkb->lkb_astqueue);
                         type = lkb->lkb_ast_type;
                         lkb->lkb_ast_type = 0;
+                        bastmode = lkb->lkb_bastmode;
                         found = 1;
                         break;
                 }
@@ -84,13 +87,12 @@ static void process_asts(void)
 
                 cast = lkb->lkb_astfn;
                 bast = lkb->lkb_bastfn;
-                bmode = lkb->lkb_bastmode;
 
                 if ((type & AST_COMP) && cast)
                         cast(lkb->lkb_astparam);
 
                 if ((type & AST_BAST) && bast)
-                        bast(lkb->lkb_astparam, bmode);
+                        bast(lkb->lkb_astparam, 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 6ee276c74c52..1b5fc5f428fd 100644
--- a/fs/dlm/ast.h
+++ b/fs/dlm/ast.h
@@ -1,7 +1,7 @@
 /******************************************************************************
 *******************************************************************************
 **
-**  Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
+**  Copyright (C) 2005-2008 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);
+void dlm_add_ast(struct dlm_lkb *lkb, int type, int bastmode);
 void dlm_del_ast(struct dlm_lkb *lkb);
 
 void dlm_astd_wake(void);
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 724ddac91538..7b758dadbdd6 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -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);
+        dlm_add_ast(lkb, AST_COMP, 0);
 }
 
 static inline void queue_cast_overlap(struct dlm_rsb *r, struct dlm_lkb *lkb)
@@ -320,10 +320,8 @@ static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
 {
         if (is_master_copy(lkb))
                 send_bast(r, lkb, rqmode);
-        else {
-                lkb->lkb_bastmode = rqmode;
-                dlm_add_ast(lkb, AST_BAST);
-        }
+        else
+                dlm_add_ast(lkb, AST_BAST, rqmode);
 }
 
 /*
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index b3832c67194a..065149e84f42 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -175,7 +175,7 @@ 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)
+void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode)
 {
         struct dlm_ls *ls;
         struct dlm_user_args *ua;
@@ -208,6 +208,8 @@ void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
 
         ast_type = lkb->lkb_ast_type;
         lkb->lkb_ast_type |= type;
+        if (bastmode)
+                lkb->lkb_bastmode = bastmode;
 
         if (!ast_type) {
                 kref_get(&lkb->lkb_ref);
diff --git a/fs/dlm/user.h b/fs/dlm/user.h
index 35eb6a13d616..1c9686492286 100644
--- a/fs/dlm/user.h
+++ b/fs/dlm/user.h
@@ -9,7 +9,7 @@
 #ifndef __USER_DOT_H__
 #define __USER_DOT_H__
 
-void dlm_user_add_ast(struct dlm_lkb *lkb, int type);
+void dlm_user_add_ast(struct dlm_lkb *lkb, int type, int bastmode);
 int dlm_user_init(void);
 void dlm_user_exit(void);
 int dlm_device_deregister(struct dlm_ls *ls);