Re: silent semantic changes with reiser4

[Erik Hensema]

Jan Dittmer (jdittmer@xxxxxxxx) wrote:
> Zitat von Helge Hafting <helge.hafting@xxxxxxx>:
>> Tom Vier wrote:
>> 
>> >What's wrong with ~/.thumbcache or a daemon that manages system wide
>> cache?
>> >
>> >  
>> >
>> Moving a file doen't move the associated thumbnail, and then you
>> notice something is missing, or don't find the file, or have to wait
>> for regeneration when the app notices a file without a tumb. 
>> That could take some time if you moved a directory full of postscript
>> files, for example.
>
> Use hash + filename in ~/.thumbcache and be smart when trying to find a
> thumbnail. That really can all be done in userspace.

Yes, it can be done. It's slow, ineffecient and dangerous (rename
a file, lose the thumbnail... so you'd have to do some garbage
collection on the thumbnail cache).

Thumbnails are actually an *excelent* example of a multistream
file. Renaming/moving a file leaves the image<->thumbnail link
intact. Removing the image removes the thumbnail. Copying the
file to another multistream-file capable machine also copies the
thumbnail, saving you the time to regenerate the thumbnail.
When the target machine doesn't understand a multistream file,
you simply lose the thumbnail, no harm done.

-- 
Erik Hensema <erik@xxxxxxxxxxx>
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