fs: take the ACL checks to common code

Replace the ->check_acl method with a ->get_acl method that simply reads an
ACL from disk after having a cache miss.  This means we can replace the ACL
checking boilerplate code with a single implementation in namei.c.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/ext2/file.c

@@ -102,6 +102,6 @@ const struct inode_operations ext2_file_inode_operations = {
 	.removexattr	= generic_removexattr,
 #endif
 	.setattr	= ext2_setattr,
-	.check_acl	= ext2_check_acl,
+	.get_acl	= ext2_get_acl,
 	.fiemap		= ext2_fiemap,
 };