1 files changed, 18 insertions, 0 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index eb2bd826bb04..667735fb45e6 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -122,6 +122,24 @@ loop:
         cur_trans->delayed_refs.flushing = 0;
         cur_trans->delayed_refs.run_delayed_start = 0;
         cur_trans->delayed_refs.seq = 1;
+
+        /*
+         * although the tree mod log is per file system and not per transaction,
+         * the log must never go across transaction boundaries.
+         */
+        smp_mb();
+        if (!list_empty(&fs_info->tree_mod_seq_list)) {
+                printk(KERN_ERR "btrfs: tree_mod_seq_list not empty when "
+                        "creating a fresh transaction\n");
+                WARN_ON(1);
+        }
+        if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) {
+                printk(KERN_ERR "btrfs: tree_mod_log rb tree not empty when "
+                        "creating a fresh transaction\n");
+                WARN_ON(1);
+        }
+        atomic_set(&fs_info->tree_mod_seq, 0);
+
         init_waitqueue_head(&cur_trans->delayed_refs.seq_wait);
         spin_lock_init(&cur_trans->commit_lock);
         spin_lock_init(&cur_trans->delayed_refs.lock);