lkml.org 
[lkml]   [2006]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/4] pass b_size to ->get_block()
Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
> Pass amount of disk needs to be mapped to get_block().
> This way one can modify the fs ->get_block() functions
> to map multiple blocks at the same time.

I can't say I terribly like this patch. Initialising b_size all over the
place seems fragile.

We're _already_ setting bh.b_size to the right thing in
alloc_page_buffers(), and for a bh which is attached to
pagecache_page->private, there's no reason why b_size would ever change.

So what I think I'll do is to convert those places where you're needlessly
assigning to b_size into temporary WARN_ON(b_size != blocksize).

The only place where we need to initialise b_size is where we've got a
non-pagecache bh allocated on the stack.

We need to be sure that no ->get_block() implementations write garbage into
bh->b_size if something goes wrong. b_size on a pagecache-based
buffer_head must remain inviolate.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-03-02 02:53    [from the cache]
©2003-2011 Jasper Spaans