bcachefs: bucket_lock() is now a sleepable lock

fsck_err() may sleep - it takes a mutex and may allocate memory, so
bucket_lock() needs to be a sleepable lock.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/buckets.c

@@ -367,7 +367,6 @@ static inline int update_replicas(struct bch_fs *c, struct bkey_s_c k,
 	struct printbuf buf = PRINTBUF;
 
 	percpu_down_read(&c->mark_lock);
-	buf.atomic++;
 
 	idx = bch2_replicas_entry_idx(c, r);
 	if (idx < 0 &&
@@ -795,7 +794,6 @@ static int mark_stripe_bucket(struct btree_trans *trans,
 	/* * XXX doesn't handle deletion */
 
 	percpu_down_read(&c->mark_lock);
-	buf.atomic++;
 	g = PTR_GC_BUCKET(ca, ptr);
 
 	if (g->dirty_sectors ||

fs/bcachefs/buckets.h

@@ -70,12 +70,15 @@ union ulong_byte_assert {
 static inline void bucket_unlock(struct bucket *b)
 {
 	BUILD_BUG_ON(!((union ulong_byte_assert) { .ulong = 1UL << BUCKET_LOCK_BITNR }).byte);
-	bit_spin_unlock(BUCKET_LOCK_BITNR, (void *) &b->lock);
+
+	clear_bit_unlock(BUCKET_LOCK_BITNR, (void *) &b->lock);
+	wake_up_bit((void *) &b->lock, BUCKET_LOCK_BITNR);
 }
 
 static inline void bucket_lock(struct bucket *b)
 {
-	bit_spin_lock(BUCKET_LOCK_BITNR, (void *) &b->lock);
+	wait_on_bit_lock((void *) &b->lock, BUCKET_LOCK_BITNR,
+			 TASK_UNINTERRUPTIBLE);
 }
 
 static inline struct bucket_array *gc_bucket_array(struct bch_dev *ca)