[dm-devel] [PATCH 00/10] fixes for kpartx -d

[Benjamin Marzinski]

On Sat, May 06, 2017 at 12:05:49AM +0200, Martin Wilck wrote:
> Working on a bug report about kpartx not properly removing
> partitions for loop devices, I realized a number of glitches
> and improperly handled corner cases in the kpartx code for
> deleting partitions. Some mappings are not deleted although
> they should be, and others are deleted although that is clearly
> wrong.
> 
> This patch series fixes the issues I found. The series starts
> with a test program demonstrating the problems. The program
> succeeds only after all patches of this series are applied.
> 
> Here is my summary of what I think how kpartx should behave:
> 
>   1) kpartx should delete all mappings it created beforehand.
>   2) kpartx should handle partitions on dm devices and other devices
>      (e.g. loop devices) equally well.
>   3) kpartx should only delete "partitions", which are single-target
>      linear mappings into a block device. Other maps should not be touched.
>   4) kpartx should only delete mappings it created itself beforehand.
>      In particular, it shouldn't delete LVM LVs, even if they are fully
>      contained in the block device at hand and thus look like partitions
>      in the first place. (For historical compatibility reasons, allow
>      such mappings to be deleted with the -f/--force flag).
>   5) DM map names may be changed, thus kpartx shouldn't rely on them to
>      check whether a mapping is a partition of a particular device. It is
>      legal for a partition of /dev/loop0 to be named "loop0".
> 
> One patch has an obvious libdevmapper equivalent and is therefore
> included although this series is otherwise focused only on kpartx.

ACK for the set (with the possible exception of "kpartx: avoid ioctl
error for loop devices", if we don't need to keep the dm_no_partitions
code anymore).

-Ben

> 
> Feedback is welcome.
> 
> Martin Wilck (10):
>   kpartx: test-kpartx: new unit test program
>   kpartx: avoid ioctl error for loop devices
>   kpartx: remove is_loop_device
>   kpartx: dm_remove_partmaps: support non-dm devices
>   kpartx: dm_devn: return error for non-existent device
>   kpartx: don't treat multi-linear mappings as partitions
>   libmultipath: don't treat multi-linear mappings as partitions
>   kpartx: use partition UUID for non-DM devices
>   kpartx: use absolute path for regular files
>   kpartx: find_loop_by_file: use sysfs
> 
>  kpartx/devmapper.c       |  39 +++++---
>  kpartx/devmapper.h       |   2 +-
>  kpartx/kpartx.c          |  42 +++++++-
>  kpartx/lopart.c          |  73 ++++++--------
>  kpartx/lopart.h          |   1 -
>  kpartx/test-kpartx       | 253 +++++++++++++++++++++++++++++++++++++++++++++++
>  libmultipath/devmapper.c |  15 +--
>  7 files changed, 356 insertions(+), 69 deletions(-)
>  create mode 100755 kpartx/test-kpartx
> 
> -- 
> 2.12.2