JPEG thumbnailing latency

[Vitezslav Kotrla <vitko post cz>]

I may have finally solved one of thumbnailing mysteries I've met in
nautilus 2.22:

While working with ufraw I've noticed that exported JPEG files got only
generic 'image' type icon, not proper thumbnail. When I accidentally
renamed one such file, it was instantly re-thumbnailed, this time
correctly.

It looks like ufraw creates empty JPEG file when conversion begins and
it takes some time while data are finally written. In the meantime
nautilus fails to thumbnail an empty file, so generic image filetype
icon is assigned.

Also enfuse works this way - it creates empty JPEG file first and starts
writing output data later (20 seconds during my simple test, but of
course even later depending on the workload).

I wonder what is the proper solution?

(Of course this is rather general issue, not limited to JPEG filetype
mentioned in $SUBJ, I just wanted to provide some real world example. It
may have been discussed or reported before, maybe someone can provide
references?)

Vit