Btrfs: Add delayed iput

iput() can trigger new transactions if we are dropping the
final reference, so calling it in btrfs_commit_transaction
may end up deadlock. This patch adds delayed iput to avoid
the issue.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 728e8fe5d2cc..75b31caade29 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -333,6 +333,9 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
         memset(trans, 0, sizeof(*trans));
         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 
+        if (throttle)
+                btrfs_run_delayed_iputs(root);
+
         return 0;
 }
 
@@ -991,11 +994,11 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 mutex_unlock(&root->fs_info->trans_mutex);
 
                 if (flush_on_commit) {
-                        btrfs_start_delalloc_inodes(root);
-                        ret = btrfs_wait_ordered_extents(root, 0);
+                        btrfs_start_delalloc_inodes(root, 1);
+                        ret = btrfs_wait_ordered_extents(root, 0, 1);
                         BUG_ON(ret);
                 } else if (snap_pending) {
-                        ret = btrfs_wait_ordered_extents(root, 1);
+                        ret = btrfs_wait_ordered_extents(root, 0, 1);
                         BUG_ON(ret);
                 }
 
@@ -1113,6 +1116,10 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                 current->journal_info = NULL;
 
         kmem_cache_free(btrfs_trans_handle_cachep, trans);
+
+        if (current != root->fs_info->transaction_kthread)
+                btrfs_run_delayed_iputs(root);
+
         return ret;
 }