Re: [PATCH 3/3] AFS: Implement basic file write support

[Nick Piggin]

David Howells wrote:
> Nick Piggin <nickpiggin@xxxxxxxxxxxx> 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?

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