Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  RCUify freeing acls, let check_acl() go ahead in RCU mode if acl is cached
  get rid of boilerplate switches in posix_acl.h
  fix block device fallout from ->fsync() changes

1 files changed, 26 insertions, 48 deletions

diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 951bba82d50d..b7681102a4b9 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -9,6 +9,7 @@
 #define __LINUX_POSIX_ACL_H
 
 #include <linux/slab.h>
+#include <linux/rcupdate.h>
 
 #define ACL_UNDEFINED_ID        (-1)
 
@@ -38,7 +39,10 @@ struct posix_acl_entry {
 };
 
 struct posix_acl {
-        atomic_t                a_refcount;
+        union {
+                atomic_t                a_refcount;
+                struct rcu_head         a_rcu;
+        };
         unsigned int            a_count;
         struct posix_acl_entry  a_entries[0];
 };
@@ -65,7 +69,7 @@ static inline void
 posix_acl_release(struct posix_acl *acl)
 {
         if (acl && atomic_dec_and_test(&acl->a_refcount))
-                kfree(acl);
+                kfree_rcu(acl, a_rcu);
 }
 
 
@@ -84,20 +88,22 @@ extern struct posix_acl *get_posix_acl(struct inode *, int);
 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
 
 #ifdef CONFIG_FS_POSIX_ACL
-static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
+static inline struct posix_acl **acl_by_type(struct inode *inode, int type)
 {
-        struct posix_acl **p, *acl;
         switch (type) {
         case ACL_TYPE_ACCESS:
-                p = &inode->i_acl;
-                break;
+                return &inode->i_acl;
         case ACL_TYPE_DEFAULT:
-                p = &inode->i_default_acl;
-                break;
+                return &inode->i_default_acl;
         default:
-                return ERR_PTR(-EINVAL);
+                BUG();
         }
-        acl = ACCESS_ONCE(*p);
+}
+
+static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
+{
+        struct posix_acl **p = acl_by_type(inode, type);
+        struct posix_acl *acl = ACCESS_ONCE(*p);
         if (acl) {
                 spin_lock(&inode->i_lock);
                 acl = *p;
@@ -108,41 +114,20 @@ static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
         return acl;
 }
 
-static inline int negative_cached_acl(struct inode *inode, int type)
+static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
 {
-        struct posix_acl **p, *acl;
-        switch (type) {
-        case ACL_TYPE_ACCESS:
-                p = &inode->i_acl;
-                break;
-        case ACL_TYPE_DEFAULT:
-                p = &inode->i_default_acl;
-                break;
-        default:
-                BUG();
-        }
-        acl = ACCESS_ONCE(*p);
-        if (acl)
-                return 0;
-        return 1;
+        return rcu_dereference(*acl_by_type(inode, type));
 }
 
 static inline void set_cached_acl(struct inode *inode,
                                   int type,
                                   struct posix_acl *acl)
 {
-        struct posix_acl *old = NULL;
+        struct posix_acl **p = acl_by_type(inode, type);
+        struct posix_acl *old;
         spin_lock(&inode->i_lock);
-        switch (type) {
-        case ACL_TYPE_ACCESS:
-                old = inode->i_acl;
-                inode->i_acl = posix_acl_dup(acl);
-                break;
-        case ACL_TYPE_DEFAULT:
-                old = inode->i_default_acl;
-                inode->i_default_acl = posix_acl_dup(acl);
-                break;
-        }
+        old = *p;
+        rcu_assign_pointer(*p, posix_acl_dup(acl));
         spin_unlock(&inode->i_lock);
         if (old != ACL_NOT_CACHED)
                 posix_acl_release(old);
@@ -150,18 +135,11 @@ static inline void set_cached_acl(struct inode *inode,
 
 static inline void forget_cached_acl(struct inode *inode, int type)
 {
-        struct posix_acl *old = NULL;
+        struct posix_acl **p = acl_by_type(inode, type);
+        struct posix_acl *old;
         spin_lock(&inode->i_lock);
-        switch (type) {
-        case ACL_TYPE_ACCESS:
-                old = inode->i_acl;
-                inode->i_acl = ACL_NOT_CACHED;
-                break;
-        case ACL_TYPE_DEFAULT:
-                old = inode->i_default_acl;
-                inode->i_default_acl = ACL_NOT_CACHED;
-                break;
-        }
+        old = *p;
+        *p = ACL_NOT_CACHED;
         spin_unlock(&inode->i_lock);
         if (old != ACL_NOT_CACHED)
                 posix_acl_release(old);