Reread partition table when a partition is added

diff -u -p -r1.1.1.1 check.c
@@ -391,19 +391,44 @@ void register_disk(struct gendisk *disk)
 	blkdev_put(bdev);
 }
 
+/*
+ * Determine the last partition.
+ * Return the partition number or 0 if there is no partition
+ */
+static int get_last_partition(struct gendisk *disk)
+{
+	int	n, ret = 0;
+
+	for (n=0; n < disk->minors ; n++) {
+		if (disk->part[n])
+			ret=n+1;
+	}
+
+	return(ret);
+}
+
 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 {
 	struct parsed_partitions *state;
+	struct hd_struct *phd;
 	int p, res;
+	int is_busy = 0, last_partition = 0;
+
+	if (bdev->bd_part_count) {
+		is_busy = 1;
+		last_partition=get_last_partition(disk);
+	}
 
-	if (bdev->bd_part_count)
-		return -EBUSY;
 	res = invalidate_partition(disk, 0);
 	if (res)
 		return res;
 	bdev->bd_invalidated = 0;
-	for (p = 1; p < disk->minors; p++)
-		delete_partition(disk, p);
+
+	if (!is_busy) {
+		for (p = 1; p < disk->minors; p++)
+			delete_partition(disk, p);
+	}
+
 	if (disk->fops->revalidate_disk)
 		disk->fops->revalidate_disk(disk);
 	if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))

@@ -411,13 +436,29 @@ int rescan_partitions(struct gendisk *di
 	for (p = 1; p < state->limit; p++) {
 		sector_t size = state->parts[p].size;
 		sector_t from = state->parts[p].from;
+
+		if (is_busy && p<=last_partition) {
+			phd=disk->part[p-1];
+			if (phd != NULL && (phd->start_sect != from ||
+			 	phd->nr_sects != size)) {
+				printk(KERN_INFO
+					"Existing partition was changed. "
+					"Reboot is required.\n");
+				res=-EBUSY;
+				break;
+			}
+		}
+
 		if (!size)
 			continue;
-		add_partition(disk, p, from, size);
+
+		if (!is_busy || p>last_partition) {
+			add_partition(disk, p, from, size);
 #ifdef CONFIG_BLK_DEV_MD
-		if (state->parts[p].flags)
-			md_autodetect_dev(bdev->bd_dev+p);
+			if (state->parts[p].flags)
+				md_autodetect_dev(bdev->bd_dev+p);
 #endif
+		}
 	}
 	kfree(state);
 	return res;

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