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drbd: disconnect, if the wrong UUIDs are attached on a connected peer

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[ Upstream commit b17b59602b6dcf8f97a7dc7bc489a48388d7063a ]

With "on-no-data-accessible suspend-io", DRBD requires the next attach
or connect to be to the very same data generation uuid tag it lost last.

If we first lost connection to the peer,
then later lost connection to our own disk,
we would usually refuse to re-connect to the peer,
because it presents the wrong data set.

However, if the peer first connects without a disk,
and then attached its disk, we accepted that same wrong data set,
which would be "unexpected" by any user of that DRBD
and cause "undefined results" (read: very likely data corruption).

The fix is to forcefully disconnect as soon as we notice that the peer
attached to the "wrong" dataset.

Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Lars Ellenberg 2018-12-20 17:23:32 +01:00 committed by Greg Kroah-Hartman
parent 3b5d41253b
commit 5c857f014b
1 changed files with 1 additions and 1 deletions
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2
drivers/block/drbd/drbd_receiver.c
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@ -3890,7 +3890,7 @@ static int receive_uuids(struct drbd_connection *connection, struct packet_info
kfree(device->p_uuid);
device->p_uuid = p_uuid;
if (device->state.conn < C_CONNECTED &&
if ((device->state.conn < C_CONNECTED || device->state.pdsk == D_DISKLESS) &&
device->state.disk < D_INCONSISTENT &&
device->state.role == R_PRIMARY &&
(device->ed_uuid & ~((u64)1)) != (p_uuid[UI_CURRENT] & ~((u64)1))) {