diff options
| author | Lars Ellenberg <lars@linbit.com> | 2014-04-28 18:43:26 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-04-30 13:46:55 -0600 |
| commit | 074f4afeb2277bd5ecb9fa7f91eaffa55e262126 (patch) | |
| tree | 3fc09287b0094b8e2fd19c09c9b70e85135a35eb | |
| parent | 20c68fdea1646ed746abf19122d7699493927005 (diff) | |
drbd: fix a race between start_resync and send_and_submit
In the drbd make request function, specifically in
drbd_send_and_submit(), we decide whether we want to send the actual
write request, or only a "set this block out of sync" information.
We do so based on the current connection state, while holding the req_lock.
The connection state is not supposed to change while holding the req_lock.
But in drbd_start_resync, we did change that state anyways,
while only holding the global_state_lock, which is enough to change
sync-after dependencies (paused vs active resync), but
not good enough to change the connection state.
Fix: in drbd_start_resync, first grab the req_lock to serialize with
drbd_send_and_submit(), before grabbing the global_state_lock
to be able to evaluate the sync-after dependencies.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | drivers/block/drbd/drbd_worker.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 26338bedb25b..34dde10fae48 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -1686,11 +1686,15 @@ void drbd_start_resync(struct drbd_device *device, enum drbd_conns side) } clear_bit(B_RS_H_DONE, &device->flags); - write_lock_irq(&global_state_lock); + /* req_lock: serialize with drbd_send_and_submit() and others + * global_state_lock: for stable sync-after dependencies */ + spin_lock_irq(&device->resource->req_lock); + write_lock(&global_state_lock); /* Did some connection breakage or IO error race with us? */ if (device->state.conn < C_CONNECTED || !get_ldev_if_state(device, D_NEGOTIATING)) { - write_unlock_irq(&global_state_lock); + write_unlock(&global_state_lock); + spin_unlock_irq(&device->resource->req_lock); mutex_unlock(device->state_mutex); return; } @@ -1730,7 +1734,8 @@ void drbd_start_resync(struct drbd_device *device, enum drbd_conns side) } _drbd_pause_after(device); } - write_unlock_irq(&global_state_lock); + write_unlock(&global_state_lock); + spin_unlock_irq(&device->resource->req_lock); if (r == SS_SUCCESS) { /* reset rs_last_bcast when a resync or verify is started, |