busy vnodes.
* dir_create_entry_ref() used get_vnode() incorrectly (and could therefore
potentially prevent a file system from doing proper locking when called
from the kernel).
* The vnode_store now uses this for its acquire_unreferenced_ref()
implementation (and therefore for the page writer).
* read_into_cache() and write_to_cache() were still marked inline.
* The system will now wait 10 secs for a busy vnode before returning an error.
* It will also no longer panic in that case.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22485 a95241bf-73f2-0310-859d-f6bbb57e9c96