42 lines
1.5 KiB
Diff
42 lines
1.5 KiB
Diff
From: Sebastian Riemer <sebastian.riemer@profitbricks.com>
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Date: Fri, 25 Jan 2013 12:46:59 +0100
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Subject: md: protect against crash upon fsync on ro array
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Bug-Debian: http://bugs.debian.org/696650
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commit 0ecfa11f08c79be05eb00bba537e764e6672774d upstream.
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If an fsync occurs on a read-only array, we need to send a
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completion for the IO and may not increment the active IO count.
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Otherwise, we hit a bug trace and can't stop the MD array anymore.
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By advice of Christoph Hellwig we return success upon a flush
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request but we return -EROFS for other writes.
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We detect flush requests by checking if the bio has zero sectors.
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Cc: Christoph Hellwig <hch@infradead.org>
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Cc: Ben Hutchings <ben@decadent.org.uk>
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Cc: NeilBrown <neilb@suse.de>
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Signed-off-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
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Reported-by: Ben Hutchings <ben@decadent.org.uk>
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Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>
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Signed-off-by: NeilBrown <neilb@suse.de>
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---
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drivers/md/md.c | 4 ++++
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1 file changed, 4 insertions(+)
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diff --git a/drivers/md/md.c b/drivers/md/md.c
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index 3db3d1b..1e634a6 100644
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--- a/drivers/md/md.c
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+++ b/drivers/md/md.c
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@@ -307,6 +307,10 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
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bio_io_error(bio);
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return;
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}
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+ if (mddev->ro == 1 && unlikely(rw == WRITE)) {
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+ bio_endio(bio, bio_sectors(bio) == 0 ? 0 : -EROFS);
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+ return;
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+ }
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smp_rmb(); /* Ensure implications of 'active' are visible */
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rcu_read_lock();
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if (mddev->suspended) {
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