netfs: Remove global reference count lock.

* libnetfs/drop-node.c: Remove use of netfs_node_refcnt_lock.
* libnetfs/init-init.c: Remove netfs_node_refcnt_lock.
* libnetfs/make-node.c: Initialize refcounts in refcounts_init.
* libnetfs/netfs.h: Use refcounts_t for tracking node references. Remove
netfs_node_refcnt_lock. Add netfs_nref_light, netfs_nrele_light and
handler netfs_try_dropping_softrefs. Adjust comments.
* libnetfs/nput.c: Use refcounts_t. Call netfs_try_dropping_softrefs to
remove any soft reference that the translator might have acquired
during the lifetime of the node. Implement empty
netfs_try_dropping_softrefs.
* libnetfs/nref.c: Implement netfs_nref_light.
* libnetfs/nrele.c: Use refcounts_t and netfs_try_dropping_softrefs.
Implement netfs_nrele_light.
* ftpfs/dir.c: Use netfs_nref without locking the old
netfs_node_refcnt_lock.
* ftpfs/node.c: Likewise.
* usermux/mux.c: Use netfs_nref to increase hard references of the node.
* hostmux/mux.c: Use netfs_nref to increase hard references of the node.
* trans/fakeroot.c (new_node): Use a light reference when storing a node in the
hash table.
* trans/fakeroot.c (netfs_try_dropping_softrefs): Implement
netfs_try_dropping_softrefs to remove the node from the hash table.
* trans/fakeroot.c (netfs_node_norefs): Remove code to remove the node
from the hash table.
* trans/fakeroot.c (netfs_S_dir_lookup): Simplify lookup code since we
don't need to lock netfs_node_refcnt_lock anymore.
* procfs/netfs.c: Remove use of netfs_node_refcnt_lock.
* nfs/cache.c: Add mutex to handle exclusive access to nodehash. This
replaces the use of netfs_node_refcnt_lock.
* nfs/cache.c (lookup_handle): Use nodehash_ihash_lock when accessing
nodehash. Use netfs_nref_light to add one soft reference to the node
just added to nodehash.
* nfs/cache.c (netfs_node_norefs): Use netfs_nref. Don't use
netfs_node_refcnt_lock and don't remove the node from nodehash here.
* nfs/cache.c (netfs_try_dropping_softrefs): Drop the light reference
when the node has no more hard references.
* nfs/cache.c (recache_handle): Use nodehash_ihash_lock instead.
* nfs/ops.c (netds_attempt_unlink): Use refcounts_references.
* console/console.c (netfs_node_norefs): Use a soft reference to store
a node in dir_node, cons_node, disp_node, inp_node.
* console/console.c (netfs_try_dropping_softrefs): When dropping all
soft references remove node pointer from the fields above.

2 files changed, 7 insertions, 28 deletions

diff --git a/ftpfs/dir.c b/ftpfs/dir.c
index 733a2dcf..2ea29b53 100644
--- a/ftpfs/dir.c
+++ b/ftpfs/dir.c
@@ -654,10 +654,8 @@ ftpfs_dir_lookup (struct ftpfs_dir *dir, const char *name,
 	{
 	  /* If there's already a node, add a ref so that it doesn't go
              away.  */
-	  pthread_spin_lock (&netfs_node_refcnt_lock);
-	  if (e->node)
-	    e->node->references++;
-	  pthread_spin_unlock (&netfs_node_refcnt_lock);
+          if (e->node)
+            netfs_nref (e->node);
 
 	  if (! e->node)
 	    /* No node; make one and install it into E.  */
@@ -682,11 +680,7 @@ ftpfs_dir_lookup (struct ftpfs_dir *dir, const char *name,
 		  if (!err && dir->num_live_entries++ == 0)
 		    /* Keep a reference to dir's node corresponding to
 		       children.  */
-		    {
-		      pthread_spin_lock (&netfs_node_refcnt_lock);
-		      dir->node->references++;
-		      pthread_spin_unlock (&netfs_node_refcnt_lock);
-		    }
+                    netfs_nref (dir->node);
 		}
 	    }
 
@@ -737,10 +731,8 @@ ftpfs_dir_null_lookup (struct ftpfs_dir *dir, struct node **node)
     /* We've got a dir entry, get a node for it.  */
     {
       /* If there's already a node, add a ref so that it doesn't go away.  */
-      pthread_spin_lock (&netfs_node_refcnt_lock);
       if (e->node)
-	e->node->references++;
-      pthread_spin_unlock (&netfs_node_refcnt_lock);
+        netfs_nref (e->node);
 
       if (! e->node)
 	/* No node; make one and install it into E.  */
@@ -749,11 +741,7 @@ ftpfs_dir_null_lookup (struct ftpfs_dir *dir, struct node **node)
 
 	  if (!err && dir->num_live_entries++ == 0)
 	    /* Keep a reference to dir's node corresponding to children.  */
-	    {
-	      pthread_spin_lock (&netfs_node_refcnt_lock);
-	      dir->node->references++;
-	      pthread_spin_unlock (&netfs_node_refcnt_lock);
-	    }
+            netfs_nref (dir->node);
 	}
 
       if (! err)
@@ -783,10 +771,7 @@ ftpfs_dir_create (struct ftpfs *fs, struct node *node, const char *rmt_path,
       return ENOMEM;
     }
 
-  /* Hold a reference to the new dir's node.  */
-  pthread_spin_lock (&netfs_node_refcnt_lock);
-  node->references++;
-  pthread_spin_unlock (&netfs_node_refcnt_lock);
+  netfs_nref (node);
 
   hurd_ihash_init (&new->htable, offsetof (struct ftpfs_dir_entry, dir_locp));
   hurd_ihash_set_gki (&new->htable, ihash_hash, ihash_compare);
diff --git a/ftpfs/node.c b/ftpfs/node.c
index 74cd402e..cc9bf433 100644
--- a/ftpfs/node.c
+++ b/ftpfs/node.c
@@ -84,10 +84,7 @@ netfs_node_norefs (struct node *node)
 {
   struct netnode *nn = node->nn;
 
-  /* Ftpfs_detach_node does ref count frobbing (of other nodes), so we have
-     to unlock NETFS_NODE_REFCNT_LOCK during it.  */
-  node->references++;
-  pthread_spin_unlock (&netfs_node_refcnt_lock);
+  netfs_nref (node);
 
   /* Remove NODE from any entry it is attached to.  */
   ftpfs_detach_node (node);
@@ -108,7 +105,4 @@ netfs_node_norefs (struct node *node)
 
   free (nn);
   free (node);
-
-  /* Caller expects us to leave this locked... */
-  pthread_spin_lock (&netfs_node_refcnt_lock);
 }