Messages in this thread | | | Date | Fri, 11 May 2007 16:14:39 +1000 | From | Nick Piggin <> | Subject | Re: [PATCH 3/3] AFS: Implement basic file write support |
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David Howells wrote: > Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > >>Why do you call SetPageUptodate when the page is not up to date? >>That leaks uninitialised data, AFAIKS. > > > It only seems that way. If afs_prepare_write() is called, but doesn't return > an error, then afs_commit_write() will be called, and it seems that the copy > in of the data will be guaranteed not to fail by the caller.
Not only does it seem that way, it is that way :) PG_uptodate is being set when the page is not uptodate, isn't it?
> Furthermore, afs_prepare_page() will have filled in the missing bits. > > And whilst all that is going on, the page lock will be help by the caller, so > that no-one else can access the partially complete page.
When a page is uptodate in pagecache, the generic read and nopage functions do not take the page lock. So how are you excluding those?
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