Implement lookup for . and ..

* procfs.c (procfs_lookup): Keep track of the parent directory,
  implement the lookup of the dot-directories.  (procfs_cleanup):
  Release the reference to the parent node, if applicable.
* procfs.h: Add a comment about the parent reference.
* netfs.c (netfs_attempt_lookup): Lock the looked up node after
  the directory has been unlocked, in case they are the same.

1 files changed, 4 insertions, 1 deletions

diff --git a/procfs.h b/procfs.h
index b44db6e3..42eed0e2 100644
--- a/procfs.h
+++ b/procfs.h
@@ -22,7 +22,10 @@ struct procfs_node_ops
 
   /* Lookup NAME in this directory, and store the result in *np.  The
      returned node should be created by lookup() using procfs_make_node() 
-     or a derived function.  */
+     or a derived function.  Note that the parent will be kept alive as
+     long as the child exists, so you can safely reference the parent's
+     data from the child.  You may want to consider locking if there's
+     any mutation going on, though.  */
   error_t (*lookup) (void *hook, const char *name, struct node **np);
 
   /* Destroy this node.  */