tree 01e6510de480d3595ccff315d777770490e51f9c
parent 9d412a43c3b26e1e549319e5eec26f0829f9f74d
author Al Viro <viro@zeniv.linux.org.uk> 1300451376 -0400
committer Al Viro <viro@zeniv.linux.org.uk> 1300452899 -0400

fix deadlock in pivot_root()

Don't hold vfsmount_lock over the loop traversing ->mnt_parent;
do check_mnt(new.mnt) under namespace_sem instead; combined with
namespace_sem held over all that code it'll guarantee the stability
of ->mnt_parent chain all the way to the root.

Doing check_mnt() outside of namespace_sem in case of pivot_root()
is wrong anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>