From 91f6a538d625d360400eb03ce4d65297c695302c Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Wed, 26 Jul 2023 16:56:57 +0100 Subject: [PATCH] btrfs: don't start transaction when joining with TRANS_JOIN_NOSTART commit 4490e803e1fe9fab8db5025e44e23b55df54078b upstream. When joining a transaction with TRANS_JOIN_NOSTART, if we don't find a running transaction we end up creating one. This goes against the purpose of TRANS_JOIN_NOSTART which is to join a running transaction if its state is at or below the state TRANS_STATE_COMMIT_START, otherwise return an -ENOENT error and don't start a new transaction. So fix this to not create a new transaction if there's no running transaction at or below that state. CC: stable@vger.kernel.org # 4.14+ Fixes: a6d155d2e363 ("Btrfs: fix deadlock between fiemap and transaction commits") Signed-off-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/transaction.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 7353f33c082c2..a555567594418 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -279,10 +279,11 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info, spin_unlock(&fs_info->trans_lock); /* - * If we are ATTACH, we just want to catch the current transaction, - * and commit it. If there is no transaction, just return ENOENT. + * If we are ATTACH or TRANS_JOIN_NOSTART, we just want to catch the + * current transaction, and commit it. If there is no transaction, just + * return ENOENT. */ - if (type == TRANS_ATTACH) + if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART) return -ENOENT; /*