tree a5b4f6b4f130ab4093010f378c9ad00a7b9da95b
parent adf91f58dac9f177a061d9b206d853a9db3db70a
author Adriana Kobylak <anoo@us.ibm.com> 1563397740 -0500
committer Adriana Kobylak <anoo@us.ibm.com> 1563900467 -0500

ubi: Rewrite freePriority

freePriority is called by RedundancyPriority::priority() to ensure that
there are no duplicate priority values. Originally, freePriority would
call priority() whenever it updated a priority value, but this would call
freePriority again. This can cause the priorities stored on flash to not
match the D-Bus values. The priorities on flash are used to determine
which version to boot from so that leads to unexpected behavior.

Example is if A has priority 1 and B has priority 2, and the priority of
B is changed to 1, this triggers the new value of 1 to be stored on
flash, then A is bumped to 2, but then B that originally had 2 is bumped
to 3, so that at the end of the operation, B has priority 3 on flash but
the correct 1 in D-Bus.

The solution is to prevent freePriority from calling itself, by sorting
all versions by priority in ascending order, so that if a version is
bumped, then only the remaining versions need to be checked. Then
locally update the priority values on flash and on D-Bus for each
changed one.

Tested: Changed priorities multipled times and verified the mismatch is not
        seen anymore.

Change-Id: I704ee98f356a1a77f431b83e4b9d787b2671aeb2
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>