Messages in this thread | | | Subject | Re: [patch 1/2] mm: dont clear PG_uptodate in invalidate_complete_page2() | From | Miklos Szeredi <> | Date | Wed, 25 Jun 2008 15:32:55 +0200 |
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> > I haven't done an audit of all code that checks the PG_uptodate flags, > > but I suspect, that this change won't have any harmful effects. Most > > code checks page->mapping to see if the page was truncated or > > invalidated, before using it, and retries the find/read on the page if > > it wasn't. The page_cache_pipe_buf_confirm() code is an exception in > > this regard. > > What about writing path, when page is written after some previous write?
page->mapping should be checked in the write paths as well.
> Like __block_prepare_write()?
That's called with the page locked and page->mapping verified.
> > Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> > > --- > > mm/truncate.c | 1 - > > 1 file changed, 1 deletion(-) > > > > Index: linux-2.6/mm/truncate.c > > =================================================================== > > --- linux-2.6.orig/mm/truncate.c 2008-06-24 20:49:25.000000000 +0200 > > +++ linux-2.6/mm/truncate.c 2008-06-24 23:28:32.000000000 +0200 > > @@ -356,7 +356,6 @@ invalidate_complete_page2(struct address > > BUG_ON(PagePrivate(page)); > > __remove_from_page_cache(page); > > write_unlock_irq(&mapping->tree_lock); > > - ClearPageUptodate(page); > > page_cache_release(page); /* pagecache ref */ > > return 1; > > failed: > > Don't do that, add new function instead which will do exactly that, if > you do need exactly this behaviour.
I don't see any point in doing that.
> Also why isn't invalidate_complete_page() enough, if you want to have > that page to be half invalidated?
I want the page fully invalidated, and I also want splice and nfs exporting to work as for other filesystems.
Miklos
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