Bug 477023

Description of problem:
Older versions of multipath-tools would always exit with status 0
(success) when flushing multipath device maps (-f/-F). This was never
guaranteed but happened because the "r" local in multipath/main.c was
used uninitialised in these code paths (by chance, it always lands on a
freshly zeroed stack page, so although undefined the behaviour was
pretty reliable).

This was changed by commit 8497928514aa3df6d46f24d8d9b70b086e9fcfbd:

commit 8497928514aa3df6d46f24d8d9b70b086e9fcfbd
Author: Christophe Varoqui <root xa-s05 (none)>
Date:   Mon Mar 13 14:55:16 2006 +0100

   [build] minor compilation issues

   SuSE checker found some minor issues:

   - refwwid in libmultipath/configure.c:get_refwwid() might be used
   uninitialized. As dev_type is a simple 'int' there is nothing which
   prevents the unsuspecting user to call it with an unhandled value.
   We shoud rather use an enum and set refwwid to NULL to be on the
   safe side.

   - attr in libmultipath/discovery.c:devt2devname() might be used
   uninitialized. Quite unlikely, but might happen in principle.
   So better have it initialized.

   - r in multipath/main.c:main() might be used uninitialized.
   True. So have it initialized.

This causes -f/-F in more recent versions of the tools to always exit
with status 1 (failure) which does not seem correct.

This was discussed on dm-devel and a patch is now in upstream that corrects this behaviour:

https://www.redhat.com/archives/dm-devel/2008-December/msg00046.html
https://www.redhat.com/archives/dm-devel/2008-December/msg00068.html

Version-Release number of selected component (if applicable):
device-mapper-multipath-0.4.7-17

How reproducible:
100%

Steps to Reproduce:
1. run "multipath -f" with some flushable maps present
2. echo $?
3.
  
Actual results:
Always exits with status 1

Expected results:
    multipath -f <map>
    ------------------
    
    -f     flush a multipath device map specified as parameter, if unused
    
    Exit Status
          0 The map existed and was successfully flushed
          1 The map did not exist or could not be flushed
    
    multipath -F
    ------------
    
    -F     flush all unused multipath device maps
    
    Exit status
          0 At least one unused multipath device map was flushed
          1 No unused maps were found or no maps could be flushed
    
Additional info:
Two commits needed for this, one to not treat attempts to flush non-mpath maps as an error and the second to or rather than sum the return of dm_flush_map():

    commit 80cac070fd5389a17ef82deb66f7c56c8c0b21af
    Author: Christophe Varoqui <christophe.varoqui>
    Date:   Thu Dec 18 00:13:30 2008 +0100
    
        [lib] dm_flush_map on a non-multipath devmap do nothing and returns 0
        
        So that "multipath -F" can succeed when non-multipath maps are active
        on the system.
    
    commit 3237295a077327188c65456de180ec3027a8f783
    Author: Christophe Varoqui <christophe.varoqui>
    Date:   Thu Dec 18 00:01:37 2008 +0100
    
        [lib] don't add up errors in dm_flush_maps()
        
        to avoid return code overflow, as pointed by "Bryn M. Reeves",
        Redhat.