Support --update=homehost to allow updating of homehost information.

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

4 files changed, 29 insertions, 0 deletions

diff --git a/mdadm.8 b/mdadm.8
index 132052a..ebabaa4 100644
--- a/mdadm.8
+++ b/mdadm.8
@@ -651,6 +651,7 @@ argument given to this flag can be one of
 .BR summaries ,
 .BR uuid ,
 .BR name ,
+.BR homehost ,
 .BR resync ,
 .BR byteorder ,
 or
@@ -690,6 +691,14 @@ of the array as stored in the superblock.  This is only supported for
 version-1 superblocks.
 
 The
+.B homehost
+option will change the
+.I homehost
+as recorded in the superblock.  For version-0 superblocks, this is the
+same as updating the UUID.
+For version-1 superblocks, this involves updating the name.
+
+The
 .B resync
 option will cause the array to be marked
 .I dirty
diff --git a/mdadm.c b/mdadm.c
index 42fcf07..0df7369 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -568,6 +568,8 @@ int main(int argc, char *argv[])
 				continue;
 			if (strcmp(update, "name")==0)
 				continue;
+			if (strcmp(update, "homehost")==0)
+				continue;
 			if (strcmp(update, "byteorder")==0) {
 				if (ss) {
 					fprintf(stderr, Name ": must not set metadata type with --update=byteorder.\n");
diff --git a/super0.c b/super0.c
index d21032f..85e54fc 100644
--- a/super0.c
+++ b/super0.c
@@ -442,6 +442,13 @@ static int update_super0(struct mdinfo *info, void *sbv, char *update,
 		sb->state &= ~(1<<MD_SB_CLEAN);
 		sb->recovery_cp = 0;
 	}
+	if (strcmp(update, "homehost") == 0 &&
+	    homehost) {
+		uuid_set = 0;
+		update = "uuid";
+		info->uuid[0] = sb->set_uuid0;
+		info->uuid[1] = sb->set_uuid1;
+	}
 	if (strcmp(update, "uuid") == 0) {
 		if (!uuid_set && homehost) {
 			unsigned char *hash = SHA1((unsigned char*)homehost,
diff --git a/super1.c b/super1.c
index 2ccda5d..b24bcea 100644
--- a/super1.c
+++ b/super1.c
@@ -496,6 +496,17 @@ static int update_super1(struct mdinfo *info, void *sbv, char *update,
 			memcpy(bm->uuid, info->uuid, 16);
 		}
 	}
+	if (strcmp(update, "homehost") == 0 &&
+	    homehost) {
+		char *c;
+		update = "name";
+		c = strchr(sb->set_name, ':');
+		if (c)
+			strncpy(info->name, c+1, 31 - (c-sb->set_name));
+		else
+			strncpy(info->name, sb->set_name, 32);
+		info->name[33] = 0;
+	}
 	if (strcmp(update, "name") == 0) {
 		if (info->name[0] == 0)
 			sprintf(info->name, "%d", info->array.md_minor);