bcachefs: Fix hang while shutting down

If the allocator thread exited before bch2_dev_allocator_stop() was
called (because of an error), bch2_dev_allocator_quiesce() could hang.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2019-04-16 15:13:16 -04:00 committed by Kent Overstreet
parent 53beb84162
commit f80b4e64a4
3 changed files with 21 additions and 11 deletions

View file

@ -598,6 +598,9 @@ static int wait_buckets_available(struct bch_fs *c, struct bch_dev *ca)
unsigned long gc_count = c->gc_count;
int ret = 0;
ca->allocator_state = ALLOCATOR_BLOCKED;
closure_wake_up(&c->freelist_wait);
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop()) {
@ -620,6 +623,9 @@ static int wait_buckets_available(struct bch_fs *c, struct bch_dev *ca)
}
__set_current_state(TASK_RUNNING);
ca->allocator_state = ALLOCATOR_RUNNING;
closure_wake_up(&c->freelist_wait);
return ret;
}
@ -1119,14 +1125,14 @@ static int push_invalidated_bucket(struct bch_fs *c, struct bch_dev *ca, size_t
fifo_pop(&ca->free_inc, bucket);
closure_wake_up(&c->freelist_wait);
ca->allocator_blocked_full = false;
ca->allocator_state = ALLOCATOR_RUNNING;
spin_unlock(&c->freelist_lock);
goto out;
}
if (!ca->allocator_blocked_full) {
ca->allocator_blocked_full = true;
if (ca->allocator_state != ALLOCATOR_BLOCKED_FULL) {
ca->allocator_state = ALLOCATOR_BLOCKED_FULL;
closure_wake_up(&c->freelist_wait);
}
@ -1184,6 +1190,7 @@ static int bch2_allocator_thread(void *arg)
int ret;
set_freezable();
ca->allocator_state = ALLOCATOR_RUNNING;
while (1) {
cond_resched();
@ -1242,9 +1249,6 @@ static int bch2_allocator_thread(void *arg)
if (!nr ||
(nr < ALLOC_SCAN_BATCH(ca) &&
!fifo_full(&ca->free[RESERVE_MOVINGGC]))) {
ca->allocator_blocked = true;
closure_wake_up(&c->freelist_wait);
ret = wait_buckets_available(c, ca);
if (ret) {
up_read(&c->gc_lock);
@ -1253,7 +1257,6 @@ static int bch2_allocator_thread(void *arg)
}
} while (!nr);
ca->allocator_blocked = false;
up_read(&c->gc_lock);
pr_debug("%zu buckets to invalidate", nr);
@ -1266,6 +1269,8 @@ static int bch2_allocator_thread(void *arg)
stop:
pr_debug("alloc thread stopping (ret %i)", ret);
ca->allocator_state = ALLOCATOR_STOPPED;
closure_wake_up(&c->freelist_wait);
return 0;
}
@ -1457,7 +1462,8 @@ void bch2_dev_allocator_add(struct bch_fs *c, struct bch_dev *ca)
void bch2_dev_allocator_quiesce(struct bch_fs *c, struct bch_dev *ca)
{
if (ca->alloc_thread)
closure_wait_event(&c->freelist_wait, ca->allocator_blocked_full);
closure_wait_event(&c->freelist_wait,
ca->allocator_state != ALLOCATOR_RUNNING);
}
/* stop allocator thread: */

View file

@ -447,8 +447,12 @@ struct bch_dev {
* XXX: this should be an enum for allocator state, so as to include
* error state
*/
bool allocator_blocked;
bool allocator_blocked_full;
enum {
ALLOCATOR_STOPPED,
ALLOCATOR_RUNNING,
ALLOCATOR_BLOCKED,
ALLOCATOR_BLOCKED_FULL,
} allocator_state;
alloc_heap alloc_heap;

View file

@ -116,7 +116,7 @@ static bool have_copygc_reserve(struct bch_dev *ca)
spin_lock(&ca->freelist_lock);
ret = fifo_full(&ca->free[RESERVE_MOVINGGC]) ||
ca->allocator_blocked;
ca->allocator_state != ALLOCATOR_RUNNING;
spin_unlock(&ca->freelist_lock);
return ret;