Actually, Sebastian already sent an equivalent patch in <[email protected]>. And he did test it. Here's his patch with the upstream reference added.
Ben. -- Ben Hutchings Humans are not rational beings; they are rationalising beings.
From: Sebastian Riemer <[email protected]> Date: Thu, 21 Feb 2013 13:28:09 +1100 Subject: md: protect against crash upon fsync on ro array commit bbfa57c0f2243a7c31fd248d22e9861a2802cad5 upstream. If an fsync occurs on a read-only array, we need to send a completion for the IO and may not increment the active IO count. Otherwise, we hit a bug trace and can't stop the MD array anymore. By advice of Christoph Hellwig we return success upon a flush request but we return -EROFS for other writes. We detect flush requests by checking if the bio has zero sectors. Cc: Christoph Hellwig <[email protected]> Cc: Ben Hutchings <[email protected]> Cc: NeilBrown <[email protected]> Signed-off-by: Sebastian Riemer <[email protected]> Reported-by: Ben Hutchings <[email protected]> Acked-by: Paul Menzel <[email protected]> --- drivers/md/md.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 98262e5..4ef75e9 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -299,6 +299,10 @@ static int md_make_request(struct request_queue *q, struct bio *bio) bio_io_error(bio); return 0; } + if (mddev->ro == 1 && unlikely(rw == WRITE)) { + bio_endio(bio, bio_sectors(bio) == 0 ? 0 : -EROFS); + return 0; + } smp_rmb(); /* Ensure implications of 'active' are visible */ rcu_read_lock(); if (mddev->suspended) {
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