Index: subversion/libsvn_repos/fs-wrap.c
===================================================================
--- subversion/libsvn_repos/fs-wrap.c    (revision 1577313)
+++ subversion/libsvn_repos/fs-wrap.c    (working copy)
@@ -136,6 +136,8 @@
   const char *txn_name;
   svn_string_t *author = svn_hash_gets(revprop_table, SVN_PROP_REVISION_AUTHOR);
   apr_hash_t *hooks_env;
+  svn_error_t *err;
+  svn_fs_txn_t *txn;

   /* Parse the hooks-env file (if any). */
   SVN_ERR(svn_repos__parse_hooks_env(&hooks_env, repos->hooks_env_path,
@@ -143,21 +145,30 @@

   /* Begin the transaction, ask for the fs to do on-the-fly lock checks.
      We fetch its name, too, so the start-commit hook can use it.  */
-  SVN_ERR(svn_fs_begin_txn2(txn_p, repos->fs, rev,
+  SVN_ERR(svn_fs_begin_txn2(&txn, repos->fs, rev,
                             SVN_FS_TXN_CHECK_LOCKS, pool));
-  SVN_ERR(svn_fs_txn_name(&txn_name, *txn_p, pool));
+  err = svn_fs_txn_name(&txn_name, txn, pool);
+  if (err)
+    return svn_error_compose_create(err, svn_fs_abort_txn(txn, pool));

   /* We pass the revision properties to the filesystem by adding them
      as properties on the txn.  Later, when we commit the txn, these
      properties will be copied into the newly created revision. */
   revprops = svn_prop_hash_to_array(revprop_table, pool);
-  SVN_ERR(svn_repos_fs_change_txn_props(*txn_p, revprops, pool));
+  err = svn_repos_fs_change_txn_props(txn, revprops, pool);
+  if (err)
+    return svn_error_compose_create(err, svn_fs_abort_txn(txn, pool));

   /* Run start-commit hooks. */
-  SVN_ERR(svn_repos__hooks_start_commit(repos, hooks_env,
-                                        author ? author->data : NULL,
-                                        repos->client_capabilities, txn_name,
-                                        pool));
+  err = svn_repos__hooks_start_commit(repos, hooks_env,
+                                      author ? author->data : NULL,
+                                      repos->client_capabilities, txn_name,
+                                      pool);
+  if (err)
+    return svn_error_compose_create(err, svn_fs_abort_txn(txn, pool));
+
+  /* We have API promise that *TXN_P is unaffected on faulure. */
+  *txn_p = txn;