From 6f0880e11d1f83ca239c823cece00fc7d034dddb Mon Sep 17 00:00:00 2001
From: Martin Whitaker <mageia@martin-whitaker.me.uk>
Date: Sat, 21 Jan 2017 20:00:20 +0000
Subject: Don't tell the kernel about partition table changes when it rescans
 them automatically (mga#20074).

When no partitions on a DOS-partitioned disk are mounted, the kernel
automatically rescans the partition table when it is written to disk.
We shouldn't then try to update the kernel's view of the partition
table, as the list of deltas we have recorded is relative to the
previous state of the partition table, not the newly rescanned state.

The behaviour for other partition table types is unchanged.

v2 (tvignaud): just make base class assume the kernel doesn't reread, only mbr
subclass overrides need_to_tell_kernel() in order to be smarter
---
 perl-install/partition_table.pm     | 2 +-
 perl-install/partition_table/dos.pm | 8 ++++++++
 perl-install/partition_table/raw.pm | 6 ++++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/perl-install/partition_table.pm b/perl-install/partition_table.pm
index 049c7bb2e..76da83b81 100644
--- a/perl-install/partition_table.pm
+++ b/perl-install/partition_table.pm
@@ -500,7 +500,7 @@ sub write {
 	    fs::dmraid::call_dmraid('-an');
 	    fs::dmraid::call_dmraid('-ay');
 	} else {
-	    tell_kernel($hd, $tell_kernel);
+	    tell_kernel($hd, $tell_kernel) if $hd->need_to_tell_kernel();
 	}
     }
     # get major/minor again after writing the partition table so that we got them for dynamic devices
diff --git a/perl-install/partition_table/dos.pm b/perl-install/partition_table/dos.pm
index c56cdab31..69566aaa8 100644
--- a/perl-install/partition_table/dos.pm
+++ b/perl-install/partition_table/dos.pm
@@ -278,6 +278,14 @@ sub end_write {
     close $F;
 }
 
+sub need_to_tell_kernel {
+    my ($hd) = @_;
+    # If none of the partitions are mounted, the kernel will automatically rescan
+    # the partition table. If any partitions are mounted, this doesn't happen, so
+    # we need to tell the kernel what has changed.
+    return any { $_->{isMounted} } partition_table::get_normal_parts($hd);
+}
+
 sub empty_raw { { raw => [ ({}) x $nb_primary ] } }
 
 sub initialize { 
diff --git a/perl-install/partition_table/raw.pm b/perl-install/partition_table/raw.pm
index e9b293b90..ebb20b179 100644
--- a/perl-install/partition_table/raw.pm
+++ b/perl-install/partition_table/raw.pm
@@ -238,6 +238,12 @@ sub zero_MBR_and_dirty {
     fsedit::partition_table_clear_and_initialize([], $hd);
 }
 
+#- by default, we assume the kernel doesn't automatically reread partition table:
+sub need_to_tell_kernel {
+    my ($_hd) = @_;
+    1;
+}
+
 sub read_primary {
     my ($hd) = @_;
 
-- 
cgit v1.2.1