Re: [dm-devel] [mdadm PATCH] Create: tell udev md device is not ready when first created.

[Jes Sorensen <jes.sorensen@gmail.com>]

On 05/03/2017 10:32 AM, Peter Rajnoha wrote:
> On 05/02/2017 03:42 PM, Jes Sorensen wrote:
>> On 04/28/2017 01:05 AM, NeilBrown wrote:
>>>
>>> When an array is created the content is not initialized,
>>> so it could have remnants of an old filesystem or md array
>>> etc on it.
>>> udev will see this and might try to activate it, which is almost
>>> certainly not what is wanted.
>>>
>>> So create a mechanism for mdadm to communicate with udev to tell
>>> it that the device isn't ready.  This mechanism is the existance
>>> of a file /run/mdadm/created-mdXXX where mdXXX is the md device name.
>>>
>>> When creating an array, mdadm will create the file.
>>> A new udev rule file, 01-md-raid-creating.rules, will detect the
>>> precense of thst file and set ENV{SYSTEMD_READY}="0".
>>> This is fairly uniformly used to suppress actions based on the
>>> contents of the device.
>>>
>>> Signed-off-by: NeilBrown <neilb@suse.com>
>>> ---
>>>  Assemble.c                  |  2 +-
>>>  Build.c                     |  2 +-
>>>  Create.c                    |  9 +++++++-
>>>  Incremental.c               |  4 ++--
>>>  Makefile                    |  4 ++--
>>>  lib.c                       | 29 +++++++++++++++++++++++++
>>>  mdadm.h                     |  4 +++-
>>>  mdopen.c                    | 52
>>> ++++++++++++++++++++++++++++-----------------
>>>  udev-md-raid-creating.rules |  7 ++++++
>>>  9 files changed, 86 insertions(+), 27 deletions(-)
>>>  create mode 100644 udev-md-raid-creating.rules
>>
>> Applied!
>>
>
> How is this solving the problem then? The patch is flagging a device as
> not ready, then clearing the flag after some time. Where does the wiping
> happen actually?

There is *NO* wiping happening, there is *NO* wiping going to happen.

Can we stop this nonsense now!

Thank you!
Jes