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authorSebastian Riemer <sebastian.riemer@profitbricks.com>2013-02-21 13:28:09 +1100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-20 12:58:52 -0700
commitf18f43cb20c3236df02472f84f5183e01c457507 (patch)
tree319509956242335755b8e7b91f079c9ad4fa7d74
parent1fc6d3ad342542afb92cca52bc5d8569f29576e0 (diff)
downloadlwn-f18f43cb20c3236df02472f84f5183e01c457507.tar.gz
lwn-f18f43cb20c3236df02472f84f5183e01c457507.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. 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 98262e5336d0..4ef75e9c7c77 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -299,6 +299,10 @@ static int md_make_request(struct request_queue *q, struct bio *bio)
bio_io_error(bio);
return 0;
}
+ if (mddev->ro == 1 && unlikely(rw == WRITE)) {
+ bio_endio(bio, bio_sectors(bio) == 0 ? 0 : -EROFS);
+ return 0;
+ }
smp_rmb(); /* Ensure implications of 'active' are visible */
rcu_read_lock();
if (mddev->suspended) {