diff options
| author | Philipp Reisner <philipp.reisner@linbit.com> | 2010-06-23 11:20:05 +0200 |
|---|---|---|
| committer | Philipp Reisner <philipp.reisner@linbit.com> | 2010-10-14 15:04:46 +0200 |
| commit | 84dfb9f564208a0331131d1ab922382c7d61a553 (patch) | |
| tree | 1506d6c318afa4a94b13bab6af983031eac5e3cd | |
| parent | 65d922c33ebd359db25d5846929b2eafc4238fcc (diff) | |
drbd: Fixed a deadlock, probably only affected UP machines
After disconnect (most likely mdev->net_cnt == 0) and we are
still in an unstable state (!drbd_state_is_stable()). When we
get an IO request in drbd_get_max_buffers() (called from
__inc_ap_bio_cond(), called from inc_ap_bio()) we wake up
misc_wait. Misc_wait is also used in inc_ap_bio() to sleep
until the outcome of __inc_ap_bio_cond() changes. => Busy loop!
Solution: Have a dedicated wait queue for get_net_conf() and
put_net_conf().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 3 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_main.c | 1 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_receiver.c | 2 |
3 files changed, 4 insertions, 2 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index e0e08f5e0a76..aa9bb213fe70 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -947,6 +947,7 @@ struct drbd_conf { union drbd_state state; wait_queue_head_t misc_wait; wait_queue_head_t state_wait; /* upon each state change. */ + wait_queue_head_t net_cnt_wait; unsigned int send_cnt; unsigned int recv_cnt; unsigned int read_cnt; @@ -2018,7 +2019,7 @@ static inline void inc_unacked(struct drbd_conf *mdev) static inline void put_net_conf(struct drbd_conf *mdev) { if (atomic_dec_and_test(&mdev->net_cnt)) - wake_up(&mdev->misc_wait); + wake_up(&mdev->net_cnt_wait); } /** diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 440b1d5dcfe2..9fe9bdd9e33d 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2763,6 +2763,7 @@ void drbd_init_set_defaults(struct drbd_conf *mdev) init_waitqueue_head(&mdev->misc_wait); init_waitqueue_head(&mdev->state_wait); + init_waitqueue_head(&mdev->net_cnt_wait); init_waitqueue_head(&mdev->ee_wait); init_waitqueue_head(&mdev->al_wait); init_waitqueue_head(&mdev->seq_wait); diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 224c79ed16e9..22d74d79ba42 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -3775,7 +3775,7 @@ static void drbd_disconnect(struct drbd_conf *mdev) if (os.conn == C_DISCONNECTING) { struct hlist_head *h; - wait_event(mdev->misc_wait, atomic_read(&mdev->net_cnt) == 0); + wait_event(mdev->net_cnt_wait, atomic_read(&mdev->net_cnt) == 0); /* we must not free the tl_hash * while application io is still on the fly */ |