1 files changed, 52 insertions, 0 deletions

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 9f40bfc9c45c..1fffbc017bdf 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -279,6 +279,58 @@ static noinline int wait_for_commit(struct btrfs_root *root,
         return 0;
 }
 
+int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
+{
+        struct btrfs_transaction *cur_trans = NULL, *t;
+        int ret;
+
+        mutex_lock(&root->fs_info->trans_mutex);
+
+        ret = 0;
+        if (transid) {
+                if (transid <= root->fs_info->last_trans_committed)
+                        goto out_unlock;
+
+                /* find specified transaction */
+                list_for_each_entry(t, &root->fs_info->trans_list, list) {
+                        if (t->transid == transid) {
+                                cur_trans = t;
+                                break;
+                        }
+                        if (t->transid > transid)
+                                break;
+                }
+                ret = -EINVAL;
+                if (!cur_trans)
+                        goto out_unlock;  /* bad transid */
+        } else {
+                /* find newest transaction that is committing | committed */
+                list_for_each_entry_reverse(t, &root->fs_info->trans_list,
+                                            list) {
+                        if (t->in_commit) {
+                                if (t->commit_done)
+                                        goto out_unlock;
+                                cur_trans = t;
+                                break;
+                        }
+                }
+                if (!cur_trans)
+                        goto out_unlock;  /* nothing committing|committed */
+        }
+
+        cur_trans->use_count++;
+        mutex_unlock(&root->fs_info->trans_mutex);
+
+        wait_for_commit(root, cur_trans);
+
+        mutex_lock(&root->fs_info->trans_mutex);
+        put_transaction(cur_trans);
+        ret = 0;
+out_unlock:
+        mutex_unlock(&root->fs_info->trans_mutex);
+        return ret;
+}
+
 #if 0
 /*
  * rate limit against the drop_snapshot code.  This helps to slow down new