[PATCH] beginning of the shared-subtree proper

[linux-2.6-block.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 4abee9ab009f2c2dd3603b982cdca1152c3dbd8e..3782923d6d4d583091e731f6b02cd6343de82636 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -24,6 +24,7 @@
 #include <linux/mount.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
+#include "pnode.h"
 
 extern int __init init_rootfs(void);
 
@@ -662,6 +663,27 @@ out_unlock:
        return err;
 }
 
+/*
+ * recursively change the type of the mountpoint.
+ */
+static int do_change_type(struct nameidata *nd, int flag)
+{
+       struct vfsmount *m, *mnt = nd->mnt;
+       int recurse = flag & MS_REC;
+       int type = flag & ~MS_REC;
+
+       if (nd->dentry != nd->mnt->mnt_root)
+               return -EINVAL;
+
+       down_write(&namespace_sem);
+       spin_lock(&vfsmount_lock);
+       for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
+               change_mnt_propagation(m, type);
+       spin_unlock(&vfsmount_lock);
+       up_write(&namespace_sem);
+       return 0;
+}
+
 /*
  * do loopback mount.
  */
@@ -1091,6 +1113,8 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
                                    data_page);
        else if (flags & MS_BIND)
                retval = do_loopback(&nd, dev_name, flags & MS_REC);
+       else if (flags & MS_PRIVATE)
+               retval = do_change_type(&nd, flags);
        else if (flags & MS_MOVE)
                retval = do_move_mount(&nd, dev_name);
        else