helpers for acl caching + switch to those

helpers: get_cached_acl(inode, type), set_cached_acl(inode, type, acl),
forget_cached_acl(inode, type).

ubifs/xattr.c needed includes reordered, the rest is a plain switchover.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 64 insertions, 0 deletions

diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 4bc241290c2..0cdba01b775 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -83,4 +83,68 @@ extern int posix_acl_chmod_masq(struct posix_acl *, mode_t);
 extern struct posix_acl *get_posix_acl(struct inode *, int);
 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
 
+static inline struct posix_acl *get_cached_acl(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:
+                return ERR_PTR(-EINVAL);
+        }
+        acl = ACCESS_ONCE(*p);
+        if (acl) {
+                spin_lock(&inode->i_lock);
+                acl = *p;
+                if (acl != ACL_NOT_CACHED)
+                        acl = posix_acl_dup(acl);
+                spin_unlock(&inode->i_lock);
+        }
+        return acl;
+}
+
+static inline void set_cached_acl(struct inode *inode,
+                                  int type,
+                                  struct posix_acl *acl)
+{
+        struct posix_acl *old = NULL;
+        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;
+        }
+        spin_unlock(&inode->i_lock);
+        if (old != ACL_NOT_CACHED)
+                posix_acl_release(old);
+}
+
+static inline void forget_cached_acl(struct inode *inode, int type)
+{
+        struct posix_acl *old = NULL;
+        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;
+        }
+        spin_unlock(&inode->i_lock);
+        if (old != ACL_NOT_CACHED)
+                posix_acl_release(old);
+}
+
 #endif  /* __LINUX_POSIX_ACL_H */