1 files changed, 13 insertions, 2 deletions

diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index 8c0a3adc5df5..ee753536ab70 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -233,7 +233,10 @@ struct mdp_superblock_1 {
         __le32  delta_disks;    /* change in number of raid_disks               */
         __le32  new_layout;     /* new layout                                   */
         __le32  new_chunk;      /* new chunk size (512byte sectors)             */
-        __u8    pad1[128-124];  /* set to 0 when written */
+        __le32  new_offset;     /* signed number to add to data_offset in new
+                                 * layout.  0 == no-change.  This can be
+                                 * different on each device in the array.
+                                 */
 
         /* constant this-device information - 64 bytes */
         __le64  data_offset;    /* sector start of data, often 0 */
@@ -281,10 +284,18 @@ struct mdp_superblock_1 {
                                             * active device with same 'role'.
                                             * 'recovery_offset' is also set.
                                             */
+#define MD_FEATURE_RESHAPE_BACKWARDS    32 /* Reshape doesn't change number
+                                            * of devices, but is going
+                                            * backwards anyway.
+                                            */
+#define MD_FEATURE_NEW_OFFSET           64 /* new_offset must be honoured */
 #define MD_FEATURE_ALL                  (MD_FEATURE_BITMAP_OFFSET       \
                                         |MD_FEATURE_RECOVERY_OFFSET     \
                                         |MD_FEATURE_RESHAPE_ACTIVE      \
                                         |MD_FEATURE_BAD_BLOCKS          \
-                                        |MD_FEATURE_REPLACEMENT)
+                                        |MD_FEATURE_REPLACEMENT         \
+                                        |MD_FEATURE_RESHAPE_BACKWARDS   \
+                                        |MD_FEATURE_NEW_OFFSET          \
+                                        )
 
 #endif