new helper: file_inode(file)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/reiserfs/procfs.c b/fs/reiserfs/procfs.c
index e60e870..9cc0740a 100644
--- a/fs/reiserfs/procfs.c
+++ b/fs/reiserfs/procfs.c
@@ -281,7 +281,7 @@
 	}
 #if defined( REISERFS_USE_OIDMAPF )
 	if (sb_info->oidmap.use_file && (sb_info->oidmap.mapf != NULL)) {
-		loff_t size = sb_info->oidmap.mapf->f_path.dentry->d_inode->i_size;
+		loff_t size = file_inode(sb_info->oidmap.mapf)->i_size;
 		total_used += size / sizeof(reiserfs_oidinterval_d_t);
 	}
 #endif