fs: add get_acl helper

[~andy/linux] / fs / posix_acl.c

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 359d70b0e947d332ffd716479ac36f406ba39749..30524de49a6bc47c7c47e6f1f58ccddb1432d6b9 100644 (file)
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -26,6 +26,33 @@ EXPORT_SYMBOL(posix_acl_valid);
 EXPORT_SYMBOL(posix_acl_equiv_mode);
 EXPORT_SYMBOL(posix_acl_from_mode);
 
+struct posix_acl *get_acl(struct inode *inode, int type)
+{
+       struct posix_acl *acl;
+
+       acl = get_cached_acl(inode, type);
+       if (acl != ACL_NOT_CACHED)
+               return acl;
+
+       if (!IS_POSIXACL(inode))
+               return NULL;
+
+       /*
+        * A filesystem can force a ACL callback by just never filling the
+        * ACL cache. But normally you'd fill the cache either at inode
+        * instantiation time, or on the first ->get_acl call.
+        *
+        * If the filesystem doesn't have a get_acl() function at all, we'll
+        * just create the negative cache entry.
+        */
+       if (!inode->i_op->get_acl) {
+               set_cached_acl(inode, type, NULL);
+               return NULL;
+       }
+       return inode->i_op->get_acl(inode, type);
+}
+EXPORT_SYMBOL(get_acl);
+
 /*
  * Init a fresh posix_acl
  */