New RESHAPE_NO_BACKUP flag to track when backup action is needed.

Some arrays (raid10) never need a backup file, so during assembly
we can avoid the whole Grow_continue check in the case.
Achieve this using a flag set by the metadata handler.

Also get "mdadm -I" to fail if a backup process would be
needed.  It currently does fail as the kernel rejects things,
but it is nicer to have this explicit.

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

4 files changed, 17 insertions, 1 deletions

diff --git a/Assemble.c b/Assemble.c
index 227d66f..abbec47 100644
--- a/Assemble.c
+++ b/Assemble.c
@@ -1202,7 +1202,8 @@ int Assemble(struct supertype *st, char *mddev,
 	 * The code of doing this lives in Grow.c
 	 */
 #ifndef MDASSEMBLE
-	if (content->reshape_active) {
+	if (content->reshape_active &&
+	    !(content->reshape_active & RESHAPE_NO_BACKUP)) {
 		int err = 0;
 		int *fdlist = malloc(sizeof(int)* bestcnt);
 		if (verbose > 0)
@@ -1378,6 +1379,7 @@ int Assemble(struct supertype *st, char *mddev,
 			int rv;
 #ifndef MDASSEMBLE
 			if (content->reshape_active &&
+			    !(content->reshape_active & RESHAPE_NO_BACKUP) &&
 			    content->delta_disks <= 0) {
 				rv = sysfs_set_str(content, NULL,
 						   "array_state", "readonly");
diff --git a/Incremental.c b/Incremental.c
index e3639f2..2c4717c 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -513,6 +513,14 @@ int Incremental(char *devname, int verbose, int runstop,
 	if (runstop > 0 || active_disks >= info.array.working_disks) {
 		struct mdinfo *dsk;
 		/* Let's try to start it */
+
+		if (info.reshape_active && !(info.reshape_active & RESHAPE_NO_BACKUP)) {
+			fprintf(stderr, Name
+				": %s: This array is being reshaped and cannot be started\n"
+				"      by --incremental.  Please use --assemble\n",
+				chosen_name);
+			goto out;
+		}
 		if (match && match->bitmap_file) {
 			int bmfd = open(match->bitmap_file, O_RDWR);
 			if (bmfd < 0) {
@@ -1317,6 +1325,9 @@ int IncrementalScan(int verbose)
 						me->path, strerror(errno));
 			}
 		}
+		/* FIXME check for reshape_active and consider not
+		 * starting array.
+		 */
 		sra = sysfs_read(mdfd, 0, 0);
 		if (sra) {
 			if (sysfs_set_str(sra, NULL,
diff --git a/mdadm.h b/mdadm.h
index a70a005..abe7c3c 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -198,6 +198,7 @@ struct mdinfo {
 #define NO_RESHAPE		0
 #define VOLUME_RESHAPE		1
 #define CONTAINER_RESHAPE	2
+#define RESHAPE_NO_BACKUP	16 /* Mask 'or'ed in */
 	int			reshape_active;
 	unsigned long long	reshape_progress;
 	int			recovery_blocked; /* for external metadata it
diff --git a/super1.c b/super1.c
index 94b6c7f..572bd6c 100644
--- a/super1.c
+++ b/super1.c
@@ -721,6 +721,8 @@ static void getinfo_super1(struct supertype *st, struct mdinfo *info, char *map)
 
 	if (sb->feature_map & __le32_to_cpu(MD_FEATURE_RESHAPE_ACTIVE)) {
 		info->reshape_active = 1;
+		if (info->array.level == 10)
+			info->reshape_active |= RESHAPE_NO_BACKUP;
 		info->reshape_progress = __le64_to_cpu(sb->reshape_position);
 		info->new_level = __le32_to_cpu(sb->new_level);
 		info->delta_disks = __le32_to_cpu(sb->delta_disks);