From: Nikolay Borisov Date: Thu, 12 Sep 2019 15:31:44 +0000 (+0300) Subject: btrfs: Add assert to catch nested transaction commit X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=35b814f3c53e0635cbb1de3ea5d58776eafe8e20;p=linux.git btrfs: Add assert to catch nested transaction commit A recent patch to btrfs showed that there was at least 1 case where a nested transaction was committed. Nested transaction in this case means a code which has a transaction handle calls some function which in turn obtains a copy of the same transaction handle. In such cases the correct thing to do is for the lower callee to call btrfs_end_transaction which contains appropriate checks so as to not commit the transaction which will result in stale trans handler for the caller. To catch such cases add an assert in btrfs_commit_transaction ensuring btrfs_trans_handle::use_count is always 1. Reviewed-by: Josef Bacik Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 8624bdee8c5b6..8b75426c349e5 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1949,6 +1949,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans) struct btrfs_transaction *prev_trans = NULL; int ret; + ASSERT(refcount_read(&trans->use_count) == 1); + /* Stop the commit early if ->aborted is set */ if (unlikely(READ_ONCE(cur_trans->aborted))) { ret = cur_trans->aborted;