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    SubjectRe: [PATCH 1/3] Preserve the dirty bit in init_page_buffers
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    Nick Piggin <nickpiggin@yahoo.com.au> writes:

    > Eric W. Biederman wrote:
    >> Nick Piggin <nickpiggin@yahoo.com.au> writes:
    >
    >>>I would have thought we can fix this simply by removing the
    >>>broken ramdisk_set_page_dirty (as far as the comment goes, we
    >>>set CAP_NO_ACCT_DIRTY anyway, so the normal set_page_dirty
    >>>should handle everything properly, no?).
    >>
    >>
    >> No. I don't know where accounting comes into play. I didn't
    >> trace that path. But if we have a non-dirty ramdisk page with
    >> buffers (basically a hole in the middle or at the end of the ramdisk).
    >> We need to set the buffer dirty bits when we write to it.
    >
    > Accounting is done in set_page_dirty.

    Yes. What I meant was I had not looked at the implications of
    accounting, so I had not looked to see if I could use a generic
    set_dirty_page.

    I only got as far as recognizing that __set_page_dirty_no_writeback as
    not the appropriate function to use because we need to handle buffer
    heads.

    >> So I don't see how it would make sense to reuse the generic
    >> set_page_dirty, and handling all of the logic in set_page_dirty
    >> to dirty the buffer heads seemed to have made the most sense.
    >
    > That's what the generic set_page_dirty does. What I want to know
    > is why *doesn't* it make sense to reuse the generic set_page_dirty?
    > Unless there is a good reason, then reusing is better than writing
    > your own.

    I did not look at that part in detail. I only realized
    ramdisk_set_dirty_page needed to be modified upon a final review of my
    code, as it was not a case I actually hit.

    Just skimming through it again quickly I don't see a reason at this
    point to preserve a separate set_dirty_page for the ramdisk code.

    Eric
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