super1: update data_size when performing "revert-reshape".

The "data_size" is with respect to "data_offset".  When the kernel
changes "data_offset" it modifies "data_size" to match - see
md_finish_reshape() in the kernel.

So when mdadm switches the data_offset for the new data_offset, it
must update data_size correspondingly.

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

diff --git a/super1.c b/super1.c
index 042720579638f20b50bc08ed898b7515aef17f8f..6ec8542bb29d8f66e68ebe201de4d94dcfa0c647 100644 (file)
--- a/super1.c
+++ b/super1.c
@@ -1304,9 +1304,10 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
                        sb->chunksize = temp;
 
                        if (sb->feature_map & __cpu_to_le32(MD_FEATURE_NEW_OFFSET)) {
-                               sb->data_offset = __cpu_to_le64(__le64_to_cpu(sb->data_offset) +
-                                                               (long)(int32_t)__le32_to_cpu(sb->new_offset));
-                               sb->new_offset = __cpu_to_le32(-(int32_t)__le32_to_cpu(sb->new_offset));
+                               long offset_delta = (int32_t)__le32_to_cpu(sb->new_offset);
+                               sb->data_offset = __cpu_to_le64(__le64_to_cpu(sb->data_offset) + offset_delta);
+                               sb->new_offset = __cpu_to_le32(-offset_delta);
+                               sb->data_size = __cpu_to_le64(__le64_to_cpu(sb->data_size) - offset_delta);
                        }
                }
        } else if (strcmp(update, "_reshape_progress")==0)