Re: Will I need to re-format my partition for using the compression plugin?

[Edward Shishkin <edward@namesys.com>]

Fred Schaettgen wrote:

>On Thursday, 22. September 2005 18:41, Edward Shishkin wrote:
>  
>
>>Grzegorz Jaśkiewicz wrote:
>>    
>>
>>>I think there should be file attribute that says whether it is
>>>compressed/whatever/ or not.
>>>      
>>>
>>Right. All the plugins responsible for compression, etc.. will be observed
>>via pseudo-file interface
>>
>>    
>>
>>>This way, it would be possible to
>>>compress already existing files. At least, if filesystem is so
>>>flexible as everyone say, it would be possible.
>>>      
>>>
>>It will be possible to turn on/off compression at any
>>time if a file is powered by cryptcompress plugin id.
>>AFAIK changing file plugin id will be impossible (at least in reiser4)
>>    
>>
>
>I don't quite understand how the file plugin concept scales once we get more 
>of them. For instance if I want to have an additional attribute attached to 
>my files, which contains a checksum that is kept up to date whenever the file 
>is changed. I'd have to use a special file plugin for those files then, is 
>this correct?
>
Yes. It is impossible to implement all features in one file plugin. 
Checksuming means a low
performance: in order to read some bytes of such file you will need 
first to read the whole file
to check a checksum (isnt it?). So it will be suitable for a small 
number of special files.
To write this new file plugin you will want to use already existing 
cipher and compression
transform plugins (dont mix it with cryptcompress file plugin which also 
calls those plugins)
to compress and encrypt your checksumed file.
 

>In that case it's always an exclusive decision if I want my files checksummed, 
>compressed, encrypted, monitored for changes or whatever.
>
>Apparently the encryption and the compression is realized with one single file 
>plugin, so it seems that there is indeed no way to have both features 
>implemented as separate plugins.
>

Why do you need separate ones? Having only a cryptcompress file plugin 
you will be able
to create files which are either only encrypted or only compressed, just 
set the transform
plugins properly.

> Or is there another reason why you packed 
>both things into one plugin?
>

Because sometimes it is useful to compress data before encryption since 
compression
destroys vulnerable regular structure of some special files (like *.html)

>If most new file features have to be implemented 
>as part of one single plugin,
>

Then this plugin will look like a monster ;)
Not necessarily. On the oher hand, creating a separate file plugin for 
each feature
imho is not a good idea.

> then the whole concept of using file plugin
>starts looking a bit less promising in my eyes. 
>I hope I'm just wrong or the plugin interface is not set in stone yet ;)
>
>Fred
>
>
>  
>