diff options
| -rw-r--r-- | fs/bcachefs/btree_update_interior.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c index e3639008be5c..d2ecb782919b 100644 --- a/fs/bcachefs/btree_update_interior.c +++ b/fs/bcachefs/btree_update_interior.c @@ -684,12 +684,31 @@ static void btree_update_nodes_written(struct btree_update *as) /* * Wait for any in flight writes to finish before we free the old nodes - * on disk: + * on disk. But we haven't pinned those old nodes in the btree cache, + * they might have already been evicted. + * + * The update we're completing deleted references to those nodes from the + * btree, so we know if they've been evicted they can't be pulled back in. + * We just have to check if the nodes we have pointers to are still those + * old nodes, and haven't been reused. + * + * This can't be done locklessly because the data buffer might have been + * vmalloc allocated, and they're not RCU freed. We also need the + * __no_kmsan_checks annotation because even with the btree node read + * lock, nothing tells us that the data buffer has been initialized (if + * the btree node has been reused for a different node, and the data + * buffer swapped for a new data buffer). */ for (i = 0; i < as->nr_old_nodes; i++) { b = as->old_nodes[i]; - if (btree_node_seq_matches(b, as->old_nodes_seq[i])) + bch2_trans_begin(trans); + btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_read); + bool seq_matches = btree_node_seq_matches(b, as->old_nodes_seq[i]); + six_unlock_read(&b->c.lock); + bch2_trans_unlock_long(trans); + + if (seq_matches) wait_on_bit_io(&b->flags, BTREE_NODE_write_in_flight_inner, TASK_UNINTERRUPTIBLE); } |