The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y git checkout FETCH_HEAD git cherry-pick -x 4490e803e1fe9fab8db5025e44e23b55df54078b # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023091642-bonding-pessimism-6fe2@gregkh' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

4490e803e1fe ("btrfs: don't start transaction when joining with TRANS_JOIN_NOSTART")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4490e803e1fe9fab8db5025e44e23b55df54078b Mon Sep 17 00:00:00 2001 From: Filipe Manana fdmanana@suse.com Date: Wed, 26 Jul 2023 16:56:57 +0100 Subject: [PATCH] btrfs: don't start transaction when joining with TRANS_JOIN_NOSTART

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 fdmanana@suse.com Signed-off-by: David Sterba dsterba@suse.com

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 815f61d6b506..6a2a12593183 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -292,10 +292,11 @@ 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;

/*