BH_Req question

[Rajagopal Ananthanarayanan <ananth@sgi.com>]

Hi,

It seems BH_Req is set on a buffer_head by submit_bh.
What part of the code unsets this flag during normal
operations? One path seems to be block_flushpage->unmap_buffer
->clear_bit(BH_Req), but IIRC block_flushpage is used only
for truncates. There must be another path to unset BH_Req
under normal memory pressure, or (more unambiguously) on IO completion.

So: in what ways can BH_Req be unset?

Thanks for any input, i've been staring at the code for long without avail ...

cheers,

ananth.

PS: In case why the question: I've got a system with tons of
pages with buffers marked BH_Req, so try_to_free_buffers() bails
out thinking that the buffer is busy ...

-- 
--------------------------------------------------------------------------
Rajagopal Ananthanarayanan ("ananth")
Member Technical Staff, SGI.
--------------------------------------------------------------------------