Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 16/40] md: protect against crash upon fsync on ro array | Date | Tue, 12 Mar 2013 15:43:37 -0700 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Sebastian Riemer <sebastian.riemer@profitbricks.com>
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.
This patch is suitable to any -stable kernel to which it applies.
Signed-off-by: Sebastian Riemer <sebastian.riemer@profitbricks.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: NeilBrown <neilb@suse.de> Reported-by: Ben Hutchings <ben@decadent.org.uk> Acked-by: Paul Menzel <paulepanter@users.sourceforge.net> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/md.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -344,6 +344,10 @@ static void md_make_request(struct reque bio_io_error(bio); return; } + if (mddev->ro == 1 && unlikely(rw == WRITE)) { + bio_endio(bio, bio_sectors(bio) == 0 ? 0 : -EROFS); + return; + } smp_rmb(); /* Ensure implications of 'active' are visible */ rcu_read_lock(); if (mddev->suspended) {
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