Messages in this thread Patch in this message |  | | Date | Fri, 22 Dec 2000 02:49:33 +0100 | From | Jan Niehusmann <> | Subject | Re: [PATCH] Re: fs corruption with invalidate_buffers() |
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On Thu, Dec 21, 2000 at 05:01:00PM -0800, Linus Torvalds wrote: > > > On Fri, 22 Dec 2000, Jan Niehusmann wrote: > > > > The test I did initially was the following: > > > > if(!atomic_read(&bh->b_count) && > > (destroy_dirty_buffers || !buffer_dirty(bh)) > > && ! (bh->b_page && bh->b_page->mapping) > > ) > > > > That is, I was explicitely checking for a mapped page. It worked well, too. > > Is this more reasonable? > > I'd suggest just doing this instead (warning: cut-and-paste in xterm, so > white-space damage):
> which just ignores mapped buffers entirely (and doesn't test for > bh->b_page being non-NULL, because that shouldn't be allowed anyway).
Yes, looks good to me, and passes some tests. Here is a patch that has not been cut and pasted:
--- linux/fs/buffer.c.orig Thu Dec 21 20:30:03 2000 +++ linux/fs/buffer.c Fri Dec 22 02:11:29 2000 @@ -643,7 +643,12 @@ continue; for (i = nr_buffers_type[nlist]; i > 0 ; bh = bh_next, i--) { bh_next = bh->b_next_free; + + /* Another device? */ if (bh->b_dev != dev) + continue; + /* Part of a mapping? */ + if (bh->b_page->mapping) continue; if (buffer_locked(bh)) { atomic_inc(&bh->b_count);
I have one additional question: invalidate_buffers normally gets called if someone wants to make sure that, after the call, read accesses to a device really go to the device and don't get served by a cache. Is there some mechanismn that does the same thing to mapped pages?
Jan
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