super1: add new_offset field.

The 'new_offset' is used for reshaping to avoid the need
for a backup file.

For now we only report the value when it is set.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/super1.c b/super1.c
index 01743169763638578b8dc17c5cdaa179641b1526..988ea17d3a2fb6a8b4f8ffa3eb1046778ef6895f 100644 (file)
--- a/super1.c
+++ b/super1.c
@@ -58,7 +58,10 @@ struct mdp_superblock_1 {
        __u32   delta_disks;    /* change in number of raid_disks               */
        __u32   new_layout;     /* new layout                                   */
        __u32   new_chunk;      /* new chunk size (bytes)                       */
-       __u8    pad1[128-124];  /* set to 0 when written */
+       __u32   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 */
        __u64   data_offset;    /* sector start of data, often 0 */
@@ -112,8 +115,23 @@ struct misc_dev_info {
                                           */
 #define        MD_FEATURE_RESHAPE_ACTIVE       4
 #define        MD_FEATURE_BAD_BLOCKS           8 /* badblock list is not empty */
-
-#define        MD_FEATURE_ALL                  (1|2|4|8)
+#define        MD_FEATURE_REPLACEMENT          16 /* This device is replacing an
+                                           * 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_RESHAPE_BACKWARDS   \
+                                       |MD_FEATURE_NEW_OFFSET          \
+                                       )
 
 #ifndef offsetof
 #define offsetof(t,f) ((size_t)&(((t*)0)->f))
@@ -309,6 +327,11 @@ static void examine_super1(struct supertype *st, char *homehost)
        if (sb->data_offset)
                printf("    Data Offset : %llu sectors\n",
                       (unsigned long long)__le64_to_cpu(sb->data_offset));
+       if (sb->new_offset) {
+               unsigned long long offset = __le64_to_cpu(sb->data_offset);
+               offset += (signed)(int32_t)__le32_to_cpu(sb->new_offset);
+               printf("     New Offset : %llu sectors\n", offset);
+       }
        printf("   Super Offset : %llu sectors\n",
               (unsigned long long)__le64_to_cpu(sb->super_offset));
        if (__le32_to_cpu(sb->feature_map) & MD_FEATURE_RECOVERY_OFFSET)