Incremental: honor an 'enough' flag from external handlers

This is needed for imsm where:
1/ we want to report raid_disks as zero to allow mdadm -As to
   incorporate all spares
2/ we can't determine stale disks by looking at the event counts.
3/ we can't see per-subarray expectations with the info returned from
   the container level ->getinfo_super()

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Incremental.c

@@ -258,6 +258,15 @@ int Incremental(char *devname, int verbose, int runstop,
 		autof = ci->autof;
 
 	if (st->ss->container_content && st->loaded_container) {
+		if ((runstop > 0 && info.container_enough >= 0) ||
+		    info.container_enough > 0)
+			/* pass */;
+		else {
+			if (verbose)
+				fprintf(stderr, Name ": not enough devices to start the container\n");
+			return 1;
+		}
+
 		/* This is a pre-built container array, so we do something
 		 * rather different.
 		 */

mdadm.h

@@ -205,7 +205,9 @@ struct mdinfo {
 	int container_member; /* for assembling external-metatdata arrays
 			       * This is to be used internally by metadata
 			       * handler only */
-
+	int container_enough; /* flag external handlers can set to
+			       * indicate that subarrays have not enough (-1),
+			       * enough to start (0), or all expected disks (1) */
 	char 		sys_name[20];
 	struct mdinfo *devs;
 	struct mdinfo *next;

super-ddf.c

@@ -1357,6 +1357,7 @@ static void getinfo_super_ddf(struct supertype *st, struct mdinfo *info)
 							 (ddf->anchor.guid+16));
 	info->array.utime	  = 0;
 	info->array.chunk_size	  = 0;
+	info->container_enough	  = 0;
 
 
 	info->disk.major = 0;

super-intel.c

@@ -344,7 +344,6 @@ static struct imsm_disk *__get_imsm_disk(struct imsm_super *mpb, __u8 index)
 	return &mpb->disk[index];
 }
 
-#ifndef MDASSEMBLE
 /* retrieve a disk from the parsed metadata */
 static struct imsm_disk *get_imsm_disk(struct intel_super *super, __u8 index)
 {
@@ -356,7 +355,6 @@ static struct imsm_disk *get_imsm_disk(struct intel_super *super, __u8 index)
 	
 	return NULL;
 }
-#endif
 
 /* generate a checksum directly from the anchor when the anchor is known to be
  * up-to-date, currently only at load or write_super after coalescing
@@ -1528,6 +1526,20 @@ static void fixup_container_spare_uuid(struct mdinfo *inf)
 	}
 }
 
+
+static __u8 imsm_check_degraded(struct intel_super *super, struct imsm_dev *dev, int failed);
+static int imsm_count_failed(struct intel_super *super, struct imsm_dev *dev);
+
+static struct imsm_disk *get_imsm_missing(struct intel_super *super, __u8 index)
+{
+	struct dl *d;
+
+	for (d = super->missing; d; d = d->next)
+		if (d->index == index)
+			return &d->disk;
+	return NULL;
+}
+
 static void getinfo_super_imsm(struct supertype *st, struct mdinfo *info)
 {
 	struct intel_super *super = st->sb;
@@ -1562,6 +1574,53 @@ static void getinfo_super_imsm(struct supertype *st, struct mdinfo *info)
 	info->name[0] = 0;
 	info->recovery_start = MaxSector;
 
+	/* do we have the all the insync disks that we expect? */
+	if (st->loaded_container) {
+		struct imsm_super *mpb = super->anchor;
+		int max_enough = -1, i;
+
+		for (i = 0; i < mpb->num_raid_devs; i++) {
+			struct imsm_dev *dev = get_imsm_dev(super, i);
+			int failed, enough, j, missing = 0;
+			struct imsm_map *map;
+			__u8 state;
+
+			failed = imsm_count_failed(super, dev);
+			state = imsm_check_degraded(super, dev, failed);
+			map = get_imsm_map(dev, dev->vol.migr_state);
+
+			/* any newly missing disks?
+			 * (catches single-degraded vs double-degraded)
+			 */
+			for (j = 0; j < map->num_members; j++) {
+				__u32 ord = get_imsm_ord_tbl_ent(dev, i);
+				__u32 idx = ord_to_idx(ord);
+
+				if (!(ord & IMSM_ORD_REBUILD) &&
+				    get_imsm_missing(super, idx)) {
+					missing = 1;
+					break;
+				}
+			}
+
+			if (state == IMSM_T_STATE_FAILED)
+				enough = -1;
+			else if (state == IMSM_T_STATE_DEGRADED &&
+				 (state != map->map_state || missing))
+				enough = 0;
+			else /* we're normal, or already degraded */
+				enough = 1;
+
+			/* in the missing/failed disk case check to see
+			 * if at least one array is runnable
+			 */
+			max_enough = max(max_enough, enough);
+		}
+		dprintf("%s: enough: %d\n", __func__, max_enough);
+		info->container_enough = max_enough;
+	} else
+		info->container_enough = -1;
+
 	if (super->disks) {
 		__u32 reserved = imsm_reserved_sectors(super, super->disks);
 
@@ -4175,24 +4234,6 @@ static struct mdinfo *container_content_imsm(struct supertype *st)
 }
 
 
-#ifndef MDASSEMBLE
-static int imsm_open_new(struct supertype *c, struct active_array *a,
-			 char *inst)
-{
-	struct intel_super *super = c->sb;
-	struct imsm_super *mpb = super->anchor;
-	
-	if (atoi(inst) >= mpb->num_raid_devs) {
-		fprintf(stderr, "%s: subarry index %d, out of range\n",
-			__func__, atoi(inst));
-		return -ENODEV;
-	}
-
-	dprintf("imsm: open_new %s\n", inst);
-	a->info.container_member = atoi(inst);
-	return 0;
-}
-
 static __u8 imsm_check_degraded(struct intel_super *super, struct imsm_dev *dev, int failed)
 {
 	struct imsm_map *map = get_imsm_map(dev, 0);
@@ -4291,6 +4332,24 @@ static int imsm_count_failed(struct intel_super *super, struct imsm_dev *dev)
 	return failed;
 }
 
+#ifndef MDASSEMBLE
+static int imsm_open_new(struct supertype *c, struct active_array *a,
+			 char *inst)
+{
+	struct intel_super *super = c->sb;
+	struct imsm_super *mpb = super->anchor;
+	
+	if (atoi(inst) >= mpb->num_raid_devs) {
+		fprintf(stderr, "%s: subarry index %d, out of range\n",
+			__func__, atoi(inst));
+		return -ENODEV;
+	}
+
+	dprintf("imsm: open_new %s\n", inst);
+	a->info.container_member = atoi(inst);
+	return 0;
+}
+
 static int is_resyncing(struct imsm_dev *dev)
 {
 	struct imsm_map *migr_map;