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authorSebastian Riemer <sebastian.riemer@profitbricks.com>2013-02-21 13:28:09 +1100
committerNeilBrown <neilb@suse.de>2013-02-21 13:28:09 +1100
commitbbfa57c0f2243a7c31fd248d22e9861a2802cad5 (patch)
treea762bd442fe3799f3987881eb60526b4d9ea4952
parent19f949f52599ba7c3f67a5897ac6be14bfcb1200 (diff)
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md: protect against crash upon fsync on ro array
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. Cc: Christoph Hellwig <hch@infradead.org> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: NeilBrown <neilb@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Sebastian Riemer <sebastian.riemer@profitbricks.com> Reported-by: Ben Hutchings <ben@decadent.org.uk> Acked-by: Paul Menzel <paulepanter@users.sourceforge.net> Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r--drivers/md/md.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3db3d1b271f7..1e634a68541e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -307,6 +307,10 @@ static void md_make_request(struct request_queue *q, struct bio *bio)
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) {