#define MAPPING_POOL_SIZE 1024
#define PRISON_CELLS 1024
#define COMMIT_PERIOD HZ
+#define NO_SPACE_TIMEOUT_SECS 60
+
+static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
"A percentage of time allocated for copy on write");
struct workqueue_struct *wq;
struct work_struct worker;
struct delayed_work waker;
+ struct delayed_work no_space_timeout;
unsigned long last_commit_jiffies;
unsigned ref_count;
struct bio_list deferred_bio_list;
struct bio_list retry_on_resume_list;
struct rb_root sort_bio_list; /* sorted list of deferred bios */
+
+ /*
+ * Ensures the thin is not destroyed until the worker has finished
+ * iterating the active_thins list.
+ */
+ atomic_t refcount;
+ struct completion can_destroy;
};
/*----------------------------------------------------------------*/
{
int r;
- if (get_pool_mode(pool) != PM_WRITE)
+ if (get_pool_mode(pool) >= PM_READ_ONLY)
return -EINVAL;
r = dm_pool_commit_metadata(pool->pmd);
blk_finish_plug(&plug);
}
+static void thin_get(struct thin_c *tc);
+static void thin_put(struct thin_c *tc);
+
+/*
+ * We can't hold rcu_read_lock() around code that can block. So we
+ * find a thin with the rcu lock held; bump a refcount; then drop
+ * the lock.
+ */
+static struct thin_c *get_first_thin(struct pool *pool)
+{
+ struct thin_c *tc = NULL;
+
+ rcu_read_lock();
+ if (!list_empty(&pool->active_thins)) {
+ tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
+ thin_get(tc);
+ }
+ rcu_read_unlock();
+
+ return tc;
+}
+
+static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
+{
+ struct thin_c *old_tc = tc;
+
+ rcu_read_lock();
+ list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
+ thin_get(tc);
+ thin_put(old_tc);
+ rcu_read_unlock();
+ return tc;
+ }
+ thin_put(old_tc);
+ rcu_read_unlock();
+
+ return NULL;
+}
+
static void process_deferred_bios(struct pool *pool)
{
unsigned long flags;
struct bio_list bios;
struct thin_c *tc;
- rcu_read_lock();
- list_for_each_entry_rcu(tc, &pool->active_thins, list)
+ tc = get_first_thin(pool);
+ while (tc) {
process_thin_deferred_bios(tc);
- rcu_read_unlock();
+ tc = get_next_thin(pool, tc);
+ }
/*
* If there are any deferred flush bios, we must commit
queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD);
}
+/*
+ * We're holding onto IO to allow userland time to react. After the
+ * timeout either the pool will have been resized (and thus back in
+ * PM_WRITE mode), or we degrade to PM_READ_ONLY and start erroring IO.
+ */
+static void do_no_space_timeout(struct work_struct *ws)
+{
+ struct pool *pool = container_of(to_delayed_work(ws), struct pool,
+ no_space_timeout);
+
+ if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space)
+ set_pool_mode(pool, PM_READ_ONLY);
+}
+
/*----------------------------------------------------------------*/
struct noflush_work {
{
struct noflush_work w;
- INIT_WORK(&w.worker, fn);
+ INIT_WORK_ONSTACK(&w.worker, fn);
w.tc = tc;
atomic_set(&w.complete, 0);
init_waitqueue_head(&w.wait);
struct pool_c *pt = pool->ti->private;
bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
enum pool_mode old_mode = get_pool_mode(pool);
+ unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
/*
* Never allow the pool to transition to PM_WRITE mode if user
pool->process_discard = process_discard;
pool->process_prepared_mapping = process_prepared_mapping;
pool->process_prepared_discard = process_prepared_discard_passdown;
+
+ if (!pool->pf.error_if_no_space && no_space_timeout)
+ queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
break;
case PM_WRITE:
INIT_WORK(&pool->worker, do_worker);
INIT_DELAYED_WORK(&pool->waker, do_waker);
+ INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
spin_lock_init(&pool->lock);
bio_list_init(&pool->deferred_flush_bios);
INIT_LIST_HEAD(&pool->prepared_mappings);
struct pool *pool = pt->pool;
cancel_delayed_work(&pool->waker);
+ cancel_delayed_work(&pool->no_space_timeout);
flush_workqueue(pool->wq);
(void) commit(pool);
}
/*----------------------------------------------------------------
* Thin target methods
*--------------------------------------------------------------*/
+static void thin_get(struct thin_c *tc)
+{
+ atomic_inc(&tc->refcount);
+}
+
+static void thin_put(struct thin_c *tc)
+{
+ if (atomic_dec_and_test(&tc->refcount))
+ complete(&tc->can_destroy);
+}
+
static void thin_dtr(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
unsigned long flags;
+ thin_put(tc);
+ wait_for_completion(&tc->can_destroy);
+
spin_lock_irqsave(&tc->pool->lock, flags);
list_del_rcu(&tc->list);
spin_unlock_irqrestore(&tc->pool->lock, flags);
struct thin_c *tc;
struct dm_dev *pool_dev, *origin_dev;
struct mapped_device *pool_md;
+ unsigned long flags;
mutex_lock(&dm_thin_pool_table.mutex);
mutex_unlock(&dm_thin_pool_table.mutex);
- spin_lock(&tc->pool->lock);
+ atomic_set(&tc->refcount, 1);
+ init_completion(&tc->can_destroy);
+
+ spin_lock_irqsave(&tc->pool->lock, flags);
list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
- spin_unlock(&tc->pool->lock);
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
/*
* This synchronize_rcu() call is needed here otherwise we risk a
* wake_worker() call finding no bios to process (because the newly
module_init(dm_thin_init);
module_exit(dm_thin_exit);
+module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
+
MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");
projects / karo-tx-linux.git / blobdiff