IMSM/DDF: don't recognised these metadata on partitions.

These metadata are not expected on partitions, and they have
no way of differentiation whether which is correct if they
are found both on the device and on the last partition.

So if the device is a partition, refuse to read the metadata.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/util.c b/util.c
index 79d2b0fe..25f1e56a 100644
--- a/util.c
+++ b/util.c
@@ -302,6 +302,31 @@ void remove_partitions(int fd)
 #endif
 }
 
+int test_partition(int fd)
+{
+	/* Check if fd is a whole-disk or a partition.
+	 * BLKPG will return EINVAL on a partition, and BLKPG_DEL_PARTITION
+	 * will return ENXIO on an invalid partition number.
+	 */
+	struct blkpg_ioctl_arg a;
+	struct blkpg_partition p;
+	a.op = BLKPG_DEL_PARTITION;
+	a.data = (void*)&p;
+	a.datalen = sizeof(p);
+	a.flags = 0;
+	memset(a.data, 0, a.datalen);
+	p.pno = 1<<30;
+	if (ioctl(fd, BLKPG, &a) == 0)
+		/* Very unlikely, but not a partition */
+		return 0;
+	if (errno == ENXIO)
+		/* not a partition */
+		return 0;
+
+	return 1;
+}
+
+
 int enough(int level, int raid_disks, int layout, int clean,
 	   char *avail, int avail_disks)
 {