btrfs: don't start transaction when joining with TRANS_JOIN_NOSTART

commit 4490e803e1 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: a6d155d2e3 ("Btrfs: fix deadlock between fiemap and transaction commits")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Filipe Manana 2023-07-26 16:56:57 +01:00 коммит произвёл Greg Kroah-Hartman
Родитель 7ef0e8b812
Коммит f326073389
1 изменённых файлов: 4 добавлений и 3 удалений

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@ -311,10 +311,11 @@ loop:
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;
/*