While doing cleanup work on an aborted transaction, we've set
the global running transaction pointer to NULL _before_ waiting all
other transaction handles to finish, so others'd hit NULL pointer
crash when referencing the global running transaction pointer.
This first sets a hint to avoid new transaction handle joining, then
waits other existing handles to abort or finish so that we can safely
set the above global pointer to NULL.
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
---
fs/btrfs/transaction.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 5878bb4..4caa1fa 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1387,6 +1387,7 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int err)
{
struct btrfs_transaction *cur_trans = trans->transaction;
+ DEFINE_WAIT(wait);
WARN_ON(trans->use_count > 1);
@@ -1395,8 +1396,13 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans,
spin_lock(&root->fs_info->trans_lock);
list_del_init(&cur_trans->list);
if (cur_trans == root->fs_info->running_transaction) {
+ root->fs_info->trans_no_join = 1;
+ spin_unlock(&root->fs_info->trans_lock);
+ wait_event(cur_trans->writer_wait,
+ atomic_read(&cur_trans->num_writers) == 1);
+
+ spin_lock(&root->fs_info->trans_lock);
root->fs_info->running_transaction = NULL;
- root->fs_info->trans_no_join = 0;
}
spin_unlock(&root->fs_info->trans_lock);
--
1.7.7
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