ipcns: don't use global fdset for dumping namespace

We are going to replace pid on id in names of image files. The id is
uniq for each namespace, so it's more convient, if image files are
opened per namespace.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/ipc_ns.h

@@ -3,7 +3,7 @@
 
 #include "crtools.h"
 
-extern int dump_ipc_ns(int ns_pid, const struct cr_fdset *fdset);
+extern int dump_ipc_ns(int ns_pid, int ns_id);
 extern int prepare_ipc_ns(int pid);
 
 extern struct ns_desc ipc_ns_desc;

ipc_ns.c

@@ -455,20 +455,28 @@ static int dump_ipc_data(const struct cr_fdset *fdset)
 	return 0;
 }
 
-int dump_ipc_ns(int ns_pid, const struct cr_fdset *fdset)
+int dump_ipc_ns(int ns_pid, int ns_id)
 {
 	int ret;
+	struct cr_fdset *fdset;
+
+	fdset = cr_fdset_open(ns_id, _CR_FD_IPCNS_FROM, _CR_FD_IPCNS_TO, O_DUMP);
+	if (fdset == NULL)
+		return -1;
 
 	ret = switch_ns(ns_pid, &ipc_ns_desc, NULL);
 	if (ret < 0)
-		return ret;
+		goto err;
 
 	ret = dump_ipc_data(fdset);
 	if (ret < 0) {
 		pr_err("Failed to write IPC namespace data\n");
-		return ret;
+		goto err;
 	}
-	return 0;
+
+err:
+	close_cr_fdset(&fdset);
+	return ret < 0 ? -1 : 0;
 }
 
 void ipc_sem_handler(int fd, void *obj)

namespaces.c

@@ -366,7 +366,7 @@ static int do_dump_namespaces(struct pid *ns_pid, unsigned int ns_flags)
 	}
 	if (ns_flags & CLONE_NEWIPC) {
 		pr_info("Dump IPC namespace\n");
-		ret = dump_ipc_ns(ns_pid->real, fdset);
+		ret = dump_ipc_ns(ns_pid->real, ns_id);
 		if (ret < 0)
 			goto err;
 	}