bcachefs: bch2_evacuate_bucket() -> bch2_dev_tryget()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/move.c

@@ -690,6 +690,10 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 	struct bpos bp_pos = POS_MIN;
 	int ret = 0;
 
+	struct bch_dev *ca = bch2_dev_tryget(c, bucket.inode);
+	if (!ca)
+		return 0;
+
 	trace_bucket_evacuate(c, &bucket);
 
 	bch2_bkey_buf_init(&sk);
@@ -711,7 +715,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 
 	a = bch2_alloc_to_v4(k, &a_convert);
 	dirty_sectors = bch2_bucket_sectors_dirty(*a);
-	bucket_size = bch2_dev_bkey_exists(c, bucket.inode)->mi.bucket_size;
+	bucket_size = ca->mi.bucket_size;
 	fragmentation = a->fragmentation_lru;
 
 	ret = bch2_btree_write_buffer_tryflush(trans);
@@ -823,6 +827,7 @@ int bch2_evacuate_bucket(struct moving_context *ctxt,
 
 	trace_evacuate_bucket(c, &bucket, dirty_sectors, bucket_size, fragmentation, ret);
 err:
+	bch2_dev_put(ca);
 	bch2_bkey_buf_exit(&sk, c);
 	return ret;
 }