Re: Copying to loop device hangs up everything

[Momchil Velikov]

>>>>> "Marcelo" == Marcelo Tosatti <[e-mail]> writes:

Marcelo> Momchil, 

Marcelo> Your fix does not look right. We _have_ to sync pages at
Marcelo> sync_page_buffers(), we cannot "ignore" them.

>> Sure, we don't ignore them, we just don't _wait_ for them, because
>> maybe _we_ are the one to write them.  

Marcelo> What if we are not ? 

Hmm, looks like we pray to find another immediately usable page, to
finish _this_ request first, and then we will ``loop_get_bh'' the
buffer we just avoided waiting on and sync it.  

Hmm, _maybe_ it is a good idea buffers submitted for IO by the
loopback threads to themselves go _in front_ of the loopback queue ?

Regards,
-velco