Re: BH_Req question

[Rajagopal Ananthanarayanan]

Andrea Arcangeli wrote:
> 
	[ ... ]
> 
> BH_Req is never unset until the buffer is destroyed (put back on the freelist).
> BH_Req only says if such a buffer ever did any I/O yet or not. It is basically
> only used to deal with I/O errors in sync_buffers().

Interesting. Thanks for the explanation. Since submit_bh was setting BH_Req,
I was misled into thinking that end_io would unset it ...

> 
> > 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 ...
> 
> Either your debugging is wrong or you broke try_to_free_buffers because a
> buffer with BH_Req must still be perfectly freeable.

Okay, I got distracted by BH_Req, which I mistook to be in BUFFER_BUSY_BITS.
There was also BH_Lock set on the buffers, which would qualify for BUFFER_BUSY_BITS ...
so may be it is a buffer_locking problem somewhere.

cheers,

ananth.

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