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| author | Sebastian Riemer <sebastian.riemer@profitbricks.com> | 2013-02-21 13:28:09 +1100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-20 15:03:15 +0000 |
| commit | ff891f9e86ca1e125b3d07c78413a4c1dbb6ca8a (patch) | |
| tree | 3ba14784cd4c5056ea72a3251ee548a0b1f3618d | |
| parent | 554995ab65f98584d95e06e4d44f0c4d3293cee7 (diff) | |
| download | lwn-ff891f9e86ca1e125b3d07c78413a4c1dbb6ca8a.tar.gz lwn-ff891f9e86ca1e125b3d07c78413a4c1dbb6ca8a.zip | |
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.
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>
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | 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 145e378edbfa..5cbc496c6de7 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -345,6 +345,10 @@ 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) { |