From 747ded6ddfe88eb9644ee0512c061e46fe2fb09d Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sun, 26 Feb 2023 15:48:39 -0500 Subject: [PATCH] bcachefs: Fix for shared paths in write buffer flush It's possible for bch2_write_buffer_flush_one() to end up with a shared path, if called from a context that already has a btree iterator pointing to a key being flushed. We have to be careful when that happens, since we can't clone a path that holds write locks. Signed-off-by: Kent Overstreet --- fs/bcachefs/btree_write_buffer.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/fs/bcachefs/btree_write_buffer.c b/fs/bcachefs/btree_write_buffer.c index 6285532e77904..026c249a3f441 100644 --- a/fs/bcachefs/btree_write_buffer.c +++ b/fs/bcachefs/btree_write_buffer.c @@ -64,6 +64,15 @@ static int bch2_btree_write_buffer_flush_one(struct btree_trans *trans, bch2_btree_insert_key_leaf(trans, path, &wb->k, wb->journal_seq); (*fast)++; + + if (path->ref > 1) { + /* + * We can't clone a path that has write locks: if the path is + * shared, unlock before set_pos(), traverse(): + */ + bch2_btree_node_unlock_write(trans, path, path->l[0].b); + *write_locked = false; + } return 0; trans_commit: return bch2_trans_update(trans, iter, &wb->k, 0) ?: -- 2.30.2