Re: Linux Buffer Cache Does Not Support Mirroring

Stephen C. Tweedie (sct@redhat.com)
Tue, 2 Nov 1999 14:35:32 +0000 (GMT)


Hi,

On Mon, 01 Nov 1999 15:48:45 -0700, "Jeff V. Merkey"
<jmerkey@timpanogas.com> said:

> ... I could simply pass my own buffer_head elements into ll_rw_block
> or make_request(). I've found that when I do, all the drivers
> malfunction.

This most definitely works if you get the buffer_heads right.
brw_page() manages just fine with its own temporary buffer_heads,
created with create_buffers() and initialised with init_buffer(). All
swap and paging use that method. The ext3/jfs journaling code and the
raw IO code both create temporary buffer_heads for IO bypassing the
buffer cache.

> I want very much to work within a "Linux" framework, but I realize
> that what's there just aint gonna' work without a sledge hammer
> approach.

If you are trying to use temporary buffer_heads for this, then you are
already on the right track.

--Stephen

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