diff options
| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2012-07-30 09:06:26 +0200 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2012-11-08 16:58:38 +0100 |
| commit | 3b9ef85e05f123f535d4ee1c5041b80f80648e50 (patch) | |
| tree | 48ef1eeef5aa653171f68d7c4f0e57e138d3d74a /drivers/block | |
| parent | 27012382bc221a8cf6ca67ced19df699b0ba8e78 (diff) | |
drbd: fix null pointer dereference with on-congestion policy when diskless
We must not look at mdev->actlog, unless we have a get_ldev() reference.
It also does not make much sense to try to disconnect or pull-ahead of
the peer, if we don't have good local data.
Only even consider congestion policies, if our local disk is D_UP_TO_DATE.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/drbd/drbd_req.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c index c45479aaff8e..891c3d41a277 100644 --- a/drivers/block/drbd/drbd_req.c +++ b/drivers/block/drbd/drbd_req.c @@ -823,7 +823,7 @@ static void complete_conflicting_writes(struct drbd_request *req) } /* called within req_lock and rcu_read_lock() */ -static bool conn_check_congested(struct drbd_conf *mdev) +static void maybe_pull_ahead(struct drbd_conf *mdev) { struct drbd_tconn *tconn = mdev->tconn; struct net_conf *nc; @@ -834,7 +834,14 @@ static bool conn_check_congested(struct drbd_conf *mdev) on_congestion = nc ? nc->on_congestion : OC_BLOCK; if (on_congestion == OC_BLOCK || tconn->agreed_pro_version < 96) - return false; + return; + + /* If I don't even have good local storage, we can not reasonably try + * to pull ahead of the peer. We also need the local reference to make + * sure mdev->act_log is there. + */ + if (!get_ldev_if_state(mdev, D_UP_TO_DATE)) + return; if (nc->cong_fill && atomic_read(&mdev->ap_in_flight) >= nc->cong_fill) { @@ -857,8 +864,7 @@ static bool conn_check_congested(struct drbd_conf *mdev) else /*nc->on_congestion == OC_DISCONNECT */ _drbd_set_state(_NS(mdev, conn, C_DISCONNECTING), 0, NULL); } - - return congested; + put_ldev(mdev); } /* If this returns false, and req->private_bio is still set, @@ -923,7 +929,7 @@ static int drbd_process_write_request(struct drbd_request *req) rcu_read_lock(); remote = drbd_should_do_remote(mdev->state); if (remote) { - conn_check_congested(mdev); + maybe_pull_ahead(mdev); remote = drbd_should_do_remote(mdev->state); } send_oos = drbd_should_send_out_of_sync(mdev->state); |