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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
rbd: quiescing lock should wait for image requests
Syncing OSD requests doesn't really work. A single image request may be comprised of multiple object requests, each of which can go through a series of OSD requests (original, copyups, etc). On top of that, the OSD cliest may be shared with other rbd devices. What we want is to ensure that all in-flight image requests complete. Introduce rbd_dev->running_list and block in RBD_LOCK_STATE_RELEASING until that happens. New OSD requests may be started during this time. Note that __rbd_img_handle_request() acquires rbd_dev->lock_rwsem only if need_exclusive_lock() returns true. This avoids a deadlock similar to the one outlined in the previous commit between unlock and I/O that doesn't require lock, such as a read with object-map feature disabled. Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
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parent
a2b1da0979
commit
e1fddc8fdd
1 changed files with 90 additions and 14 deletions
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@ -331,6 +331,7 @@ struct rbd_img_request {
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struct rbd_obj_request *obj_request; /* obj req initiator */
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};
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struct list_head lock_item;
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struct list_head object_extents; /* obj_req.ex structs */
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struct mutex state_mutex;
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@ -410,6 +411,9 @@ struct rbd_device {
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struct work_struct released_lock_work;
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struct delayed_work lock_dwork;
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struct work_struct unlock_work;
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spinlock_t lock_lists_lock;
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struct list_head running_list;
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struct completion releasing_wait;
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wait_queue_head_t lock_waitq;
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struct workqueue_struct *task_wq;
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@ -1726,6 +1730,7 @@ static struct rbd_img_request *rbd_img_request_create(
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if (rbd_dev_parent_get(rbd_dev))
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img_request_layered_set(img_request);
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INIT_LIST_HEAD(&img_request->lock_item);
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INIT_LIST_HEAD(&img_request->object_extents);
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mutex_init(&img_request->state_mutex);
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kref_init(&img_request->kref);
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@ -1745,6 +1750,7 @@ static void rbd_img_request_destroy(struct kref *kref)
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dout("%s: img %p\n", __func__, img_request);
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WARN_ON(!list_empty(&img_request->lock_item));
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for_each_obj_request_safe(img_request, obj_request, next_obj_request)
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rbd_img_obj_request_del(img_request, obj_request);
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@ -2872,6 +2878,50 @@ static void rbd_obj_handle_request(struct rbd_obj_request *obj_req, int result)
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rbd_img_handle_request(obj_req->img_request, result);
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}
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static bool need_exclusive_lock(struct rbd_img_request *img_req)
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{
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struct rbd_device *rbd_dev = img_req->rbd_dev;
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if (!(rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK))
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return false;
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if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
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return false;
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rbd_assert(!test_bit(IMG_REQ_CHILD, &img_req->flags));
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if (rbd_dev->opts->lock_on_read)
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return true;
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return rbd_img_is_write(img_req);
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}
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static void rbd_lock_add_request(struct rbd_img_request *img_req)
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{
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struct rbd_device *rbd_dev = img_req->rbd_dev;
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lockdep_assert_held(&rbd_dev->lock_rwsem);
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spin_lock(&rbd_dev->lock_lists_lock);
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rbd_assert(list_empty(&img_req->lock_item));
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list_add_tail(&img_req->lock_item, &rbd_dev->running_list);
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spin_unlock(&rbd_dev->lock_lists_lock);
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}
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static void rbd_lock_del_request(struct rbd_img_request *img_req)
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{
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struct rbd_device *rbd_dev = img_req->rbd_dev;
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bool need_wakeup;
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lockdep_assert_held(&rbd_dev->lock_rwsem);
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spin_lock(&rbd_dev->lock_lists_lock);
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rbd_assert(!list_empty(&img_req->lock_item));
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list_del_init(&img_req->lock_item);
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need_wakeup = (rbd_dev->lock_state == RBD_LOCK_STATE_RELEASING &&
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list_empty(&rbd_dev->running_list));
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spin_unlock(&rbd_dev->lock_lists_lock);
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if (need_wakeup)
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complete(&rbd_dev->releasing_wait);
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}
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static void rbd_img_object_requests(struct rbd_img_request *img_req)
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{
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struct rbd_obj_request *obj_req;
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@ -2927,9 +2977,19 @@ static bool __rbd_img_handle_request(struct rbd_img_request *img_req,
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struct rbd_device *rbd_dev = img_req->rbd_dev;
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bool done;
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mutex_lock(&img_req->state_mutex);
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done = rbd_img_advance(img_req, result);
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mutex_unlock(&img_req->state_mutex);
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if (need_exclusive_lock(img_req)) {
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down_read(&rbd_dev->lock_rwsem);
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mutex_lock(&img_req->state_mutex);
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done = rbd_img_advance(img_req, result);
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if (done)
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rbd_lock_del_request(img_req);
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mutex_unlock(&img_req->state_mutex);
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up_read(&rbd_dev->lock_rwsem);
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} else {
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mutex_lock(&img_req->state_mutex);
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done = rbd_img_advance(img_req, result);
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mutex_unlock(&img_req->state_mutex);
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}
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if (done && *result) {
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rbd_assert(*result < 0);
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@ -3413,30 +3473,40 @@ static void rbd_acquire_lock(struct work_struct *work)
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static bool rbd_quiesce_lock(struct rbd_device *rbd_dev)
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{
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bool need_wait;
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dout("%s rbd_dev %p\n", __func__, rbd_dev);
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lockdep_assert_held_exclusive(&rbd_dev->lock_rwsem);
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if (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED)
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return false;
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rbd_dev->lock_state = RBD_LOCK_STATE_RELEASING;
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downgrade_write(&rbd_dev->lock_rwsem);
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/*
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* Ensure that all in-flight IO is flushed.
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*
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* FIXME: ceph_osdc_sync() flushes the entire OSD client, which
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* may be shared with other devices.
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*/
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ceph_osdc_sync(&rbd_dev->rbd_client->client->osdc);
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rbd_dev->lock_state = RBD_LOCK_STATE_RELEASING;
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rbd_assert(!completion_done(&rbd_dev->releasing_wait));
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need_wait = !list_empty(&rbd_dev->running_list);
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downgrade_write(&rbd_dev->lock_rwsem);
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if (need_wait)
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wait_for_completion(&rbd_dev->releasing_wait);
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up_read(&rbd_dev->lock_rwsem);
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down_write(&rbd_dev->lock_rwsem);
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if (rbd_dev->lock_state != RBD_LOCK_STATE_RELEASING)
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return false;
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rbd_assert(list_empty(&rbd_dev->running_list));
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return true;
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}
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static void __rbd_release_lock(struct rbd_device *rbd_dev)
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{
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rbd_assert(list_empty(&rbd_dev->running_list));
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rbd_unlock(rbd_dev);
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}
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/*
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* lock_rwsem must be held for write
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*/
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@ -3445,7 +3515,7 @@ static void rbd_release_lock(struct rbd_device *rbd_dev)
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if (!rbd_quiesce_lock(rbd_dev))
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return;
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rbd_unlock(rbd_dev);
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__rbd_release_lock(rbd_dev);
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/*
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* Give others a chance to grab the lock - we would re-acquire
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@ -3819,7 +3889,7 @@ static void rbd_reacquire_lock(struct rbd_device *rbd_dev)
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* Lock cookie cannot be updated on older OSDs, so do
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* a manual release and queue an acquire.
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*/
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rbd_unlock(rbd_dev);
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__rbd_release_lock(rbd_dev);
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queue_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0);
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} else {
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__rbd_lock(rbd_dev, cookie);
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@ -4085,9 +4155,12 @@ static void rbd_queue_workfn(struct work_struct *work)
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if (result)
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goto err_img_request;
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rbd_img_handle_request(img_request, 0);
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if (must_be_locked)
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if (must_be_locked) {
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rbd_lock_add_request(img_request);
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up_read(&rbd_dev->lock_rwsem);
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}
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rbd_img_handle_request(img_request, 0);
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return;
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err_img_request:
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@ -4761,6 +4834,9 @@ static struct rbd_device *__rbd_dev_create(struct rbd_client *rbdc,
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INIT_WORK(&rbd_dev->released_lock_work, rbd_notify_released_lock);
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INIT_DELAYED_WORK(&rbd_dev->lock_dwork, rbd_acquire_lock);
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INIT_WORK(&rbd_dev->unlock_work, rbd_release_lock_work);
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spin_lock_init(&rbd_dev->lock_lists_lock);
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INIT_LIST_HEAD(&rbd_dev->running_list);
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init_completion(&rbd_dev->releasing_wait);
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init_waitqueue_head(&rbd_dev->lock_waitq);
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rbd_dev->dev.bus = &rbd_bus_type;
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@ -5777,7 +5853,7 @@ static void rbd_dev_image_unlock(struct rbd_device *rbd_dev)
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{
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down_write(&rbd_dev->lock_rwsem);
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if (__rbd_is_lock_owner(rbd_dev))
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rbd_unlock(rbd_dev);
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__rbd_release_lock(rbd_dev);
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up_write(&rbd_dev->lock_rwsem);
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}
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