Refresh nodes when they're read from the start.

This is necessary for top, for instance, which keeps some files open and
re-reads them regularly. As an extra bonus we can drop the refresh hack.

* procfs.c, procfs.h: Remove the refresh hack.
  (procfs_refresh): New function, invalidates the cached contents.
* netfs.c (netfs_attempt_read, netfs_get_dirents): Call
  procfs_refresh when the read is from offset 0.
* proclist.c (proclist_make_node): Remove the refresh hack.
* dircat.c (dircat_make_node): Likewise.
  (dircat_get_contents): Use procfs_refresh to avoid keeping old data
  from the component nodes.

1 files changed, 5 insertions, 8 deletions

diff --git a/procfs.h b/procfs.h
index e8ef18b3..a9665f97 100644
--- a/procfs.h
+++ b/procfs.h
@@ -32,14 +32,6 @@ struct procfs_node_ops
 
   /* Destroy this node.  */
   void (*cleanup) (void *hook);
-
-  /* FIXME: This is needed because the root node is persistent, and we
-     want the list of processes to be updated. However, this means that
-     readdir() on the root node runs the risk of returning incoherent
-     results if done in multiple runs and processes are added/removed in
-     the meantime.  The right way to fix this is probably to add a
-     getroot() user hook function to libnetfs.  */
-  int enable_refresh_hack_and_break_readdir;
 };
 
 /* These helper functions can be used as procfs_node_ops.cleanup_contents. */
@@ -71,6 +63,11 @@ void procfs_node_chtype (struct node *np, mode_t type);
    corresponding child nodes.  */
 ino64_t procfs_make_ino (struct node *np, const char *filename);
 
+/* Forget the current cached contents for the node.  This is done before reads
+   from offset 0, to ensure that the data are recent even for utilities such as
+   top which keep some nodes open.  */
+void procfs_refresh (struct node *np);
+
 error_t procfs_get_contents (struct node *np, char **data, ssize_t *data_len);
 error_t procfs_lookup (struct node *np, const char *name, struct node **npp);
 void procfs_cleanup (struct node *np);