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    SubjectRe: [PATCH 00/21] vfs: atomic open v6 (part 2)
    On Sun, Jun 10, 2012 at 04:49:21AM +0100, Al Viro wrote:

    > So the only remaining reason for having that thing is this: what if we
    > call ->atomic_open(), but it doesn't call finish_open()? Then we need
    > to free that unused struct file. If finish_open() failed, we wouldn't.
    > Same if it succeeded and something *after* it in ->atomic_open() failed
    > (then we need to fput() that file - your code in ceph leaks it, BTW).
    > Fair enough. So we need to add one more helper that would discard that
    > half-set-up struct file as we want it to be discarded. That's all.

    Actually, I take that back - that code in ceph is unreachable when
    finish_open() succeeds.

    Anyway, see vfs.git#atomic_open; it's a port of your queue + COMPLETELY
    UNTESTED followups massaging it along the following lines:
    * ->atomic_open() takes struct file * instead of struct opendata *
    * it return int instead of struct file * - 0 for succeess, -E...
    for error, 1 for "here's your sodding dentry, do it yourself". Said
    dentry is returned via file->f_path.dentry.
    * the same had been done to atomic_open()/lookup_open()/do_last()
    * finish_open() takes struct file and returns an int
    * it *also* takes int * - used to keep track of whether we'd done
    successful do_dentry_open(), instead of "has opendata->filp been cleared?"
    as in your variant. Said int * is what your bool *created of ->atomic_open()
    and friends has been turned into. So the check in path_openat() is
    if (!(opened & FILE_OPENED)) {
    which is as explicit as it gets, IMO.

    The forest of failure exits in do_last() got cleaned up a bit, BTW. Probably
    can be cleaned up some more...

    WARNING: I haven't even tried to boot it. It builds, but this is all I can
    promise at the moment. I'm about to fall down (it's 7am here already ;-/),
    will give it some beating when I get up. It almost certainly has bugs, so
    consider that as call for review and not much more.

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      Last update: 2012-06-10 13:41    [W:0.024 / U:8.168 seconds]
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