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    Subject[PATCH 002 of 29] md: Don't acknowlege that stripe-expand is complete until it really is.

    We shouldn't acknowledge that a stripe has been expanded (When
    reshaping a raid5 by adding a device) until the moved data has
    actually been written out. However we are currently
    acknowledging (by calling md_done_sync) when the POST_XOR
    is complete and before the write.

    So track in s.locked whether there are pending writes, and don't
    call md_done_sync yet if there are.

    Note: we all set R5_LOCKED on devices which are are about to
    read from. This probably isn't technically necessary, but is
    usually done when writing a block, and justifies the use of
    s.locked here.

    This bug can lead to a crash if an array is stopped while an reshape
    is in progress.

    Cc: <stable@kernel.org>
    Signed-off-by: Neil Brown <neilb@suse.de>



    ### Diffstat output
    ./drivers/md/raid5.c | 3 +++
    1 file changed, 3 insertions(+)

    diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
    --- .prev/drivers/md/raid5.c 2008-06-27 15:30:19.000000000 +1000
    +++ ./drivers/md/raid5.c 2008-06-27 15:22:48.000000000 +1000
    @@ -2898,6 +2898,8 @@ static void handle_stripe5(struct stripe

    for (i = conf->raid_disks; i--; ) {
    set_bit(R5_Wantwrite, &sh->dev[i].flags);
    + set_bit(R5_LOCKED, &dev->flags);
    + s.locked++;
    if (!test_and_set_bit(STRIPE_OP_IO, &sh->ops.pending))
    sh->ops.count++;
    }
    @@ -2911,6 +2913,7 @@ static void handle_stripe5(struct stripe
    conf->raid_disks);
    s.locked += handle_write_operations5(sh, 1, 1);
    } else if (s.expanded &&
    + s.locked == 0 &&
    !test_bit(STRIPE_OP_POSTXOR, &sh->ops.pending)) {
    clear_bit(STRIPE_EXPAND_READY, &sh->state);
    atomic_dec(&conf->reshape_stripes);

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