Am Dienstag, den 29.01.2013, 12:19 +0100 schrieb Sebastian Riemer: […] > Any further objection? Small typo (occurs) in commit message. Thanks, Paul
From adfac4df99edc1a83dced9c732464634d3381a9f Mon Sep 17 00:00:00 2001
From: Sebastian Riemer <sebastian.riemer@xxxxxxxxxxxxxxxx>
Date: Fri, 25 Jan 2013 12:46:59 +0100
Subject: [PATCH v5] 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.
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Sebastian Riemer <sebastian.riemer@xxxxxxxxxxxxxxxx>
Reported-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Acked-by: Paul Menzel <paulepanter@xxxxxxxxxxxxxxxxxxxxx>
---
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 3db3d1b..1e634a6 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) {
--
1.7.1
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