[kpartx] bug fixes for dos extended partition [2/4]

kpartx usually doesn't create a mapping for extended partition.
However, it does if it's empty.
It's harmless but not consistent.
Attached patch makes it consistent by not creating a mapping
even when the extended partition is empty.

Please consider to apply.

If you have logical partitions in extended partition:
# parted /dev/sdc p
Disk geometry for /dev/sdc: 0.000-34686.000 megabytes
Disk label type: msdos
Minor    Start       End     Type      Filesystem  Flags
1          7.844     31.376  extended
5          7.875     23.532  logical

No mapping is created for extended partition:
# dmsetup table|grep sdc|sort
  sdc5: 0 32067 linear 8:32 16128

However, if the extended partition is empty:
# parted /dev/sdc p
Disk geometry for /dev/sdc: 0.000-34686.000 megabytes
Disk label type: msdos
Minor    Start       End     Type      Filesystem  Flags
1          7.844     31.376  extended

The following mapping is created:
# dmsetup table|grep sdc|sort
  sdc1: 0 48195 linear 8:32 16065

Jun'ichi Nomura, NEC

diff --git a/kpartx/dos.c b/kpartx/dos.c
index 445a7d9..ffa0f84 100644 (file)
--- a/kpartx/dos.c
+++ b/kpartx/dos.c
@@ -98,8 +98,11 @@ read_dos_pt(int fd, struct slice all, struct slice *sp, int ns) {
                                "dos_partition: too many slices\n");
                        break;
                }
-               if (is_extended(p.sys_type))
+               if (is_extended(p.sys_type)) {
                        n += read_extended_partition(fd, &p, sp+n, ns-n);
+                       /* hide the extended partition itself */
+                       sp[i].size = 0;
+               }
        }
        return n;
 }