From 535f60c9ef91cc662d5ccaecb2f7048a3c2241d9 Mon Sep 17 00:00:00 2001

From: Phillip Susi <psusi@ubuntu.com>

Date: Thu, 12 Jan 2012 14:53:56 -0500

Subject: [PATCH] libparted: handle logical partitions starting immediately

 after the EBR

_blkpg_add_partition() set the length of the extended partition

to 2 sectors to allow LILO to be installed there, beacuse the

linux kernel does this.  If a logical partition used that second

sector, adding it would fail beacuse of the overlap.  Now

_blkpg_add_partition() will limit the length to only the first

sector if the second is used by a logical partition.

Previously parted did create the partition table, and after a

reboot, the kernel would recognize the table, and happily create

the extended partition as 2 sectors long, thus overlapping the

logical partition, but when parted tried to recreate the same

table with BLKPG, the kernel rightly rejected it.

(cherry picked from commit f503870153eda7659b09e52e4adeda3bebf06471)

---

 NEWS                                            |  8 ++++++++

 libparted/arch/linux.c                          | 17 +++++++++++++++--

 tests/t2310-dos-extended-2-sector-min-offset.sh | 16 ++++------------

 3 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/NEWS b/NEWS

index 4d30b1b..d1ab2a6 100644

--- a/NEWS

+++ b/NEWS

@@ -11,6 +11,14 @@ GNU parted NEWS                                    -*- outline -*-

 ** Bug Fixes

+  libparted: handle logical partitions starting immediately after

+  the EBR.  Creating a logical partition one sector after the EBR

+  used to cause parted to complain that it could not inform the

+  kernel of the changes, but after a reboot, everything was fine.

+  Parted will now correctly inform the kernel of the changes, but

+  only set the length of the extended partition to 1 sector instead

+  of two, which would cause it to overlap the logical partition.

+

   If a drive was 100 times an even multiple of two, sizes specified as

   a percentage would trigger the exact placement rule and refuse to round

   to the nearest half percent.

diff --git a/libparted/arch/linux.c b/libparted/arch/linux.c

index 4daa881..788cdc3 100644

--- a/libparted/arch/linux.c

+++ b/libparted/arch/linux.c

@@ -2371,8 +2371,21 @@ _blkpg_add_partition (PedDisk* disk, const PedPartition *part)

         memset (&linux_part, 0, sizeof (linux_part));

         linux_part.start = part->geom.start * disk->dev->sector_size;

         /* see fs/partitions/msdos.c:msdos_partition(): "leave room for LILO" */

-        if (part->type & PED_PARTITION_EXTENDED)

-                linux_part.length = part->geom.length == 1 ? 512 : 1024;

+        if (part->type & PED_PARTITION_EXTENDED) {

+                linux_part.length = 1;

+                if (disk->dev->sector_size == 512) {

+                        if (linux_part.length == 1)

+                                linux_part.length = 2;

+                        PedPartition *walk;

+                        /* if the second sector is claimed by a logical partition,

+                           then there's just no room for lilo, so don't try to use it */

+                        for (walk = part->part_list; walk; walk = walk->next) {

+                                if (walk->geom.start == part->geom.start+1)

+                                        linux_part.length = 1;

+                        }

+                }

+                linux_part.length *= disk->dev->sector_size;

+        }

         else

                 linux_part.length = part->geom.length * disk->dev->sector_size;

         linux_part.pno = part->num;

diff --git a/tests/t2310-dos-extended-2-sector-min-offset.sh b/tests/t2310-dos-extended-2-sector-min-offset.sh

index 89453ae..bd7defb 100644

--- a/tests/t2310-dos-extended-2-sector-min-offset.sh

+++ b/tests/t2310-dos-extended-2-sector-min-offset.sh

@@ -1,8 +1,6 @@

 #!/bin/sh

-# Ensure that parted leaves at least 2 sectors between the beginning

+# Ensure that parted allows a single sector between the beginning

 # of an extended partition and the first logical partition.

-# Before parted-2.3, it could be made to leave just one, and that

-# would cause trouble with the Linux kernel.

 # Copyright (C) 2010-2012 Free Software Foundation, Inc.

@@ -35,7 +33,7 @@ cat <<EOF > exp || framework_failure

 BYT;

 $scsi_dev:2048s:scsi:512:512:msdos:Linux scsi_debug:;

 1:64s:128s:65s:::lba;

-5:66s:128s:63s:::;

+5:65s:128s:64s:::;

 EOF

 cat <<EOF > err.exp || framework_failure

@@ -49,15 +47,9 @@ parted --align=min -s $scsi_dev mkpart extended 64s 128s> out 2>&1 || fail=1

 parted -m -s $scsi_dev u s print

 compare /dev/null out || fail=1

-# Provoke a failure by trying to create a partition that starts just

+# Trying to create a partition that starts just

 # one sector after the start of the extended partition.

-parted --align=min -s $scsi_dev mkpart logical 65s 128s > err 2>&1 && fail=1

-compare err.exp err || fail=1

-

-# The above failed, but created the partition nonetheless.  Remove it.

-parted -s $scsi_dev rm 5 || fail=1

-

-parted --align=min -s $scsi_dev mkpart logical 66s 128s > out 2>&1 || fail=1

+parted --align=min -s $scsi_dev mkpart logical 65s 128s > out 2>&1 || fail=1

 compare /dev/null out || fail=1

 parted -m -s $scsi_dev u s print > out 2>&1

-- 

2.1.0