Re: The... reiser4 with no ambiguity

[Edward Shishkin <edward.shishkin@gmail.com>]

Ralph Ulrich wrote:
> Edward Shishkin Samstag 13 Dezember 2008 20:30:
>   
>> I don't know such vfs doctrine. Who is the keeper of this doctrine?
>> :-)))
>>     
> Please, do not be too ironicle here, because I am not an insider and english is not my motherlanguage. I meant there was a discussion that in the linux mainline kernel there should not be a filesystem which has files that can have files. A file as directory was introduced to unifiy namespace by namesys. 
>
>   
>> Subfiles mean one more step in the procedure of name resolution.
>> You should return an allocated inode to vfs for every such subfile.
>> So subfiles also can not be hidden. There is a temptation to cheat
>> vfs, so it will think that it deals with usual files, but such
>> cheating doesn't lead to happy end..
>>
>> xattrs is ugly, but working solution,
>> subfiles are nice, but it doesn't work.. ;)
>>     
>
> First of all I have to understand reiser4 with no ambiguity:
>
> Are reiser4 file-plugins _only_ to handle data effective at low-level (like your compression plugin).

Nop.

There can be new features, which
. come from vfs;
. are not related to data storage improvements;
. require a new reiser4 plugin.

A good example - xattrs.

>  I know you stress this quiet often in your mails. Or is it just your focussing for now to get reiser4 mainline?
>
> Is it not possible to introduce new extended features in reiser4 and hide these features vfs? 
>   

Yes, it is possible, but, again, those features should implement
some new (optimal, efficient, safe, reliable, etc.) form of data storage.

> In reiser4 there is no such possibility to introduce a new kind of file which is hidden from vfs?
>   

Yes, it is. For example, there are two regular file plugins in reiser4.
Both are intensively used, but vfs doesn't know about them.

> Semantics of reiser5 are totally out of scope here, but I thought of them as implementable above/on reiser4

Yes, I have pushed some technical concepts of r5 to r4 a year ago..

>  - reiser4 as the technical grounds for reiser5 (as announced by namesys).
>
> Ralph
>
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