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    SubjectRe: [RFC][PATCH] ext3: don't read inode block if the buffer has a write error


    On Mon, 23 Jun 2008, Andrew Morton wrote:
    > > I don't know why it was done like this, or if anybody actually tested
    > > any of it, but AFAIKS the best way to fix this is to simply not
    > > clear any uptodate bits upon write errors.
    >
    > There's a plausible-sounding reason for this behaviour which I forgot
    > about three years ago. Maybe Linus remembers?

    We have to drop the data at _some_ point. Maybe some errors are transient,
    but a whole lot aren't. Jank out your USB memory stick, and those writes
    will continue fail. So you can't just keep things dirty - and that also
    implies that the buffer sure as heck isn't up-to-date either.

    Yes, we could haev a "retry once or twice", but quite frankly, that has
    always been left to the low-level driver. By the time the buffer cache or
    page cache sees the error, it should be considered more than "transient",
    and the data in memory is simply not _useful_ any more.

    So clearing the uptodate bit seems to be the logical thing to do. But on
    the other hand, it's probably not helping much either, so I don't
    personally care if we keep it "uptodate" - as long as the dirty bit
    doesn't get set, and as long as there is *some* way to get rid of the bad
    buffer later.

    Linus


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