1 files changed, 39 insertions, 0 deletions

diff --git a/fs/exofs/common.h b/fs/exofs/common.h
index b1b178e61718..f0d520312d8b 100644
--- a/fs/exofs/common.h
+++ b/fs/exofs/common.h
@@ -55,6 +55,8 @@
 /* exofs Application specific page/attribute */
 # define EXOFS_APAGE_FS_DATA    (OSD_APAGE_APP_DEFINED_FIRST + 3)
 # define EXOFS_ATTR_INODE_DATA  1
+# define EXOFS_ATTR_INODE_FILE_LAYOUT   2
+# define EXOFS_ATTR_INODE_DIR_LAYOUT    3
 
 /*
  * The maximum number of files we can have is limited by the size of the
@@ -206,4 +208,41 @@ enum {
         (((name_len) + offsetof(struct exofs_dir_entry, name)  + \
           EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)
 
+/*
+ * The on-disk (optional) layout structure.
+ * sits in an EXOFS_ATTR_INODE_FILE_LAYOUT or EXOFS_ATTR_INODE_DIR_LAYOUT
+ * attribute, attached to any inode, usually to a directory.
+ */
+
+enum exofs_inode_layout_gen_functions {
+        LAYOUT_MOVING_WINDOW = 0,
+        LAYOUT_IMPLICT = 1,
+};
+
+struct exofs_on_disk_inode_layout {
+        __le16 gen_func; /* One of enum exofs_inode_layout_gen_functions */
+        __le16 pad;
+        union {
+                /* gen_func == LAYOUT_MOVING_WINDOW (default) */
+                struct exofs_layout_sliding_window {
+                        __le32 num_devices; /* first n devices in global-table*/
+                } sliding_window __packed;
+
+                /* gen_func == LAYOUT_IMPLICT */
+                struct exofs_layout_implict_list {
+                        struct exofs_dt_data_map data_map;
+                        /* Variable array of size data_map.cb_num_comps. These
+                         * are device indexes of the devices in the global table
+                         */
+                        __le32 dev_indexes[];
+                } implict __packed;
+        };
+} __packed;
+
+static inline size_t exofs_on_disk_inode_layout_size(unsigned max_devs)
+{
+        return sizeof(struct exofs_on_disk_inode_layout) +
+                max_devs * sizeof(__le32);
+}
+
 #endif /*ifndef __EXOFS_COM_H__*/