[PATCH] vfs_shadow_copy2: document ordering requirement

Uri Simchoni uri at samba.org
Wed Apr 26 17:11:11 UTC 2017


On 04/26/2017 07:16 PM, Michael Adam wrote:
> On 2017-02-03 at 16:28 +0100, Ralph Böhme wrote:
>> Hi!
>>
>> Afaict the shadow_copy2 module should be put first in the module stack. Is this
>> correct? If yes, we should document this.
>>
>> Can any of you folks who recently did more work on the module comment? Michael,
>> Jeremy, Uri?
> 
> That seems about right.
> Thinking some more whether anything might need to go before
> shadow_copy2...
> 
So far I didn't encounter a clear case in practice where it would have
to be on top, so it's difficult for me to ack this, but I have many
examples for modules (perhaps not in-tree) which can be either above or
below, and modules which want to be above:

- Modules which are agnostic to paths (e.g. vfs_offline to give one
trivial example) - don't care.
- Modules that forbid certain operations based on path, but do not
modify it - usually prefer to be above (the policy enforcement is of
user actions, user paths, you block the create_file)
- auditing - depends on your perspective. if you audit user actions, you
want user view as much as possible - be as high as you can. If you want
to monitor file system access you want to be at the bottom.

Besides, what's so special about shadow_copy2? AFAICT it translates the
path into something different - aren't there other modules that do so?
What makes it unique?

Thanks,
Uri.


> Cheers - Michael
> 
> 
>> From 52effe6955fecb8cfb728bd416c76fbb929ac311 Mon Sep 17 00:00:00 2001
>> From: Ralph Boehme <slow at samba.org>
>> Date: Fri, 3 Feb 2017 16:19:26 +0100
>> Subject: [PATCH] vfs_shadow_copy2: document ordering requirement
>>
>> For correct functionality this module should come before any other.
>>
>> Signed-off-by: Ralph Boehme <slow at samba.org>
>> ---
>>  docs-xml/manpages/vfs_shadow_copy2.8.xml | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/docs-xml/manpages/vfs_shadow_copy2.8.xml b/docs-xml/manpages/vfs_shadow_copy2.8.xml
>> index ad69cff..9199f35 100644
>> --- a/docs-xml/manpages/vfs_shadow_copy2.8.xml
>> +++ b/docs-xml/manpages/vfs_shadow_copy2.8.xml
>> @@ -39,6 +39,10 @@
>>  	</para>
>>  
>>  	<para>
>> +	This module should be put at first place in the module list.
>> +	</para>
>> +
>> +	<para>
>>  	This is a second implementation of a shadow copy module
>>  	which has the following additional features (compared to the original
>>  	<citerefentry><refentrytitle>shadow_copy</refentrytitle>
>> -- 
>> 2.9.3
>>
> 



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