From 00f04b88791ff49dc64ada18819d40a5b0671709 Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Wed, 14 Sep 2011 12:37:00 +0200 Subject: Btrfs: add sequence numbers to delayed refs Sequence numbers are needed to reconstruct the backrefs of a given extent to a certain point in time. The total set of backrefs consist of the set of backrefs recorded on disk plus the enqueued delayed refs for it that existed at that moment. This patch also adds a list that records all delayed refs which are currently in the process of being added. When walking all refs of an extent in btrfs_find_all_roots(), we freeze the current state of delayed refs, honor anythinh up to this point and prevent processing newer delayed refs to assert consistency. Signed-off-by: Arne Jansen Signed-off-by: Jan Schmidt --- fs/btrfs/transaction.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/btrfs/transaction.c') diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index a2bfedcbcabc..31a7393af64e 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -36,6 +36,8 @@ static noinline void put_transaction(struct btrfs_transaction *transaction) WARN_ON(atomic_read(&transaction->use_count) == 0); if (atomic_dec_and_test(&transaction->use_count)) { BUG_ON(!list_empty(&transaction->list)); + WARN_ON(transaction->delayed_refs.root.rb_node); + WARN_ON(!list_empty(&transaction->delayed_refs.seq_head)); memset(transaction, 0, sizeof(*transaction)); kmem_cache_free(btrfs_transaction_cachep, transaction); } @@ -108,8 +110,10 @@ loop: cur_trans->delayed_refs.num_heads = 0; cur_trans->delayed_refs.flushing = 0; cur_trans->delayed_refs.run_delayed_start = 0; + cur_trans->delayed_refs.seq = 1; spin_lock_init(&cur_trans->commit_lock); spin_lock_init(&cur_trans->delayed_refs.lock); + INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head); INIT_LIST_HEAD(&cur_trans->pending_snapshots); list_add_tail(&cur_trans->list, &root->fs_info->trans_list); -- cgit v1.2.3