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drbd: Fix a potential write ordering issue on SyncTarget nodes

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Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg 2012-03-26 15:49:13 +02:00 committed by Philipp Reisner
parent 81f448629a
commit d93f63028f
1 changed files with 30 additions and 0 deletions
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30
drivers/block/drbd/drbd_receiver.c
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@ -1911,6 +1911,33 @@ static void update_peer_seq(struct drbd_conf *mdev, unsigned int peer_seq)
}
}
static inline int overlaps(sector_t s1, int l1, sector_t s2, int l2)
{
return !((s1 + (l1>>9) <= s2) || (s1 >= s2 + (l2>>9)));
}
/* maybe change sync_ee into interval trees as well? */
static bool overlaping_resync_write(struct drbd_conf *mdev, struct drbd_peer_request *peer_req)
{
struct drbd_peer_request *rs_req;
bool rv = 0;
spin_lock_irq(&mdev->tconn->req_lock);
list_for_each_entry(rs_req, &mdev->sync_ee, w.list) {
if (overlaps(peer_req->i.sector, peer_req->i.size,
rs_req->i.sector, rs_req->i.size)) {
rv = 1;
break;
}
}
spin_unlock_irq(&mdev->tconn->req_lock);
if (rv)
dev_warn(DEV, "WARN: Avoiding concurrent data/resync write to single sector.\n");
return rv;
}
/* Called from receive_Data.
* Synchronize packets on sock with packets on msock.
*
@ -2192,6 +2219,9 @@ static int receive_Data(struct drbd_tconn *tconn, struct packet_info *pi)
list_add(&peer_req->w.list, &mdev->active_ee);
spin_unlock_irq(&mdev->tconn->req_lock);
if (mdev->state.conn == C_SYNC_TARGET)
wait_event(mdev->ee_wait, !overlaping_resync_write(mdev, peer_req));
if (mdev->tconn->agreed_pro_version < 100) {
rcu_read_lock();
switch (rcu_dereference(mdev->tconn->net_conf)->wire_protocol) {