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    SubjectRe: msync(2) bug(?), returns AOP_WRITEPAGE_ACTIVATE to userland
    Hi,

    On 10/15/07, Erez Zadok <ezk@cs.sunysb.edu> wrote:
    > Pekka, with a small change to your patch (to handle time-based cache
    > coherency), your patch worked well and passed all my tests. Thanks.
    >
    > So now I wonder if we still need the patch to prevent AOP_WRITEPAGE_ACTIVATE
    > from being returned to userland. I guess we still need it, b/c even with
    > your patch, generic_writepages() can return AOP_WRITEPAGE_ACTIVATE back to
    > the VFS and we need to ensure that doesn't "leak" outside the kernel.

    I wonder whether _not setting_ BDI_CAP_NO_WRITEBACK implies that
    ->writepage() will never return AOP_WRITEPAGE_ACTIVATE for
    !wbc->for_reclaim case which would explain why we haven't hit this bug
    before. Hugh, Andrew?

    And btw, I think we need to fix ecryptfs too.

    Pekka
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