add patch series

17 files changed, 5325 insertions, 0 deletions

diff --git a/debian/patches/0001-libdiskfs-add-diskfs_make_node_alloc-to-allocate-fat.patch b/debian/patches/0001-libdiskfs-add-diskfs_make_node_alloc-to-allocate-fat.patch
new file mode 100644
index 00000000..93242f3c
--- /dev/null
+++ b/debian/patches/0001-libdiskfs-add-diskfs_make_node_alloc-to-allocate-fat.patch
@@ -0,0 +1,141 @@
+From 433222d0178fa76e315f480321c5396e176b7103 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Fri, 16 May 2014 23:06:33 +0200
+Subject: [PATCH 01/16] libdiskfs: add diskfs_make_node_alloc to allocate fat
+ nodes
+
+libdiskfs has two kind of nodes, struct node and struct netnode.
+struct node is used to store libdiskfs specific data, while struct
+netnode contains user supplied data.  Previously, both objects were
+allocated separatly, and a pointer from the node to the netnode
+provided a mapping from the former to the latter.
+
+Provide a function diskfs_make_node_alloc that allocates both nodes in
+a contiguous region.
+
+This reduces the memory allocation overhead when creating nodes.  It
+also makes the relation between node and netnode a simple offset
+calculation.  Provide two functions to compute the netnode address
+from the node address and vice-versa.
+
+Most notably, this makes implementing a cache on top of libdiskfs
+easier.  Auxiliary data for the cache can be stored in the
+user-defined netnode, and the fat node can be used as the value.
+
+* libdiskfs/node-make.c (init_node): Move initialization here.
+(diskfs_make_node): Use init_node.
+(diskfs_make_node_alloc): New function to allocate fat nodes.
+* libdiskfs/diskfs.h (diskfs_make_node_alloc): New declaration.
+(diskfs_node_netnode): Compute netnode address from node address.
+(diskfs_netnode_node): And vice-versa.
+---
+ libdiskfs/diskfs.h    | 29 +++++++++++++++++++++++++++--
+ libdiskfs/node-make.c | 39 ++++++++++++++++++++++++++++++---------
+ 2 files changed, 57 insertions(+), 11 deletions(-)
+
+diff --git a/libdiskfs/diskfs.h b/libdiskfs/diskfs.h
+index 8151ddc..a3f860d 100644
+--- a/libdiskfs/diskfs.h
++++ b/libdiskfs/diskfs.h
+@@ -116,9 +116,12 @@ struct node
+ 
+   loff_t allocsize;
+ 
+-  ino64_t cache_id;
+-
+   int author_tracks_uid;
++
++  /* This is the last field.  We do this so that if the node is
++     allocated with the disknode in an contiguous block, it sits right
++     next to the user supplied data.  */
++  ino64_t cache_id;
+ };
+ 
+ struct diskfs_control
+@@ -685,6 +688,28 @@ diskfs_notice_filechange (struct node *np, enum file_changed_type type,
+    The new node will have one hard reference and no light references.  */
+ struct node *diskfs_make_node (struct disknode *dn);
+ 
++/* Create a new node structure.  Also allocate SIZE bytes for the
++   disknode.  The address of the disknode can be obtained using
++   diskfs_node_disknode.  The new node will have one hard reference
++   and no light references.  */
++struct node *diskfs_make_node_alloc (size_t size);
++
++/* Return the address of the disknode for NODE.  NODE must have been
++   allocated using diskfs_make_node_alloc.  */
++static inline struct disknode *
++diskfs_node_disknode (struct node *node)
++{
++  return (struct disknode *) ((char *) node + sizeof (struct node));
++}
++
++/* Return the address of the node for DISKNODE.  DISKNODE must have
++   been allocated using diskfs_make_node_alloc.  */
++static inline struct node *
++diskfs_disknode_node (struct disknode *disknode)
++{
++  return (struct node *) ((char *) disknode - sizeof (struct node));
++}
++
+ 
+ /* The library also exports the following functions; they are not generally
+    useful unless you are redefining other functions the library provides. */
+diff --git a/libdiskfs/node-make.c b/libdiskfs/node-make.c
+index 2b6ef2a..ff0cc0d 100644
+--- a/libdiskfs/node-make.c
++++ b/libdiskfs/node-make.c
+@@ -19,16 +19,9 @@
+ #include <fcntl.h>
+ 
+ 
+-/* Create a and return new node structure with DN as its physical disknode.
+-   The node will have one hard reference and no light references.  */
+-struct node *
+-diskfs_make_node (struct disknode *dn)
++static struct node *
++init_node (struct node *np, struct disknode *dn)
+ {
+-  struct node *np = malloc (sizeof (struct node));
+-
+-  if (np == 0)
+-    return 0;
+-
+   np->dn = dn;
+   np->dn_set_ctime = 0;
+   np->dn_set_atime = 0;
+@@ -52,3 +45,31 @@ diskfs_make_node (struct disknode *dn)
+ 
+   return np;
+ }
++
++/* Create a and return new node structure with DN as its physical disknode.
++   The node will have one hard reference and no light references.  */
++struct node *
++diskfs_make_node (struct disknode *dn)
++{
++  struct node *np = malloc (sizeof (struct node));
++
++  if (np == 0)
++    return 0;
++
++  return init_node (np, dn);
++}
++
++/* Create a new node structure.  Also allocate SIZE bytes for the
++   disknode.  The address of the disknode can be obtained using
++   diskfs_node_disknode.  The new node will have one hard reference
++   and no light references.  */
++struct node *
++diskfs_make_node_alloc (size_t size)
++{
++  struct node *np = malloc (sizeof (struct node) + size);
++
++  if (np == NULL)
++    return NULL;
++
++  return init_node (np, diskfs_node_disknode (np));
++}
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0002-libnetfs-add-netfs_make_node_alloc-to-allocate-fat-n.patch b/debian/patches/0002-libnetfs-add-netfs_make_node_alloc-to-allocate-fat-n.patch
new file mode 100644
index 00000000..18a3e13d
--- /dev/null
+++ b/debian/patches/0002-libnetfs-add-netfs_make_node_alloc-to-allocate-fat-n.patch
@@ -0,0 +1,116 @@
+From 208885b037f1ad120f54c081c9c32f991bcbb7be Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sun, 18 May 2014 13:34:12 +0200
+Subject: [PATCH 02/16] libnetfs: add netfs_make_node_alloc to allocate fat
+ nodes
+
+libnetfs has two kind of nodes, struct node and struct netnode.
+struct node is used to store libnetfs specific data, while struct
+netnode contains user supplied data.  Previously, both objects were
+allocated separatly, and a pointer from the node to the netnode
+provided a mapping from the former to the latter.
+
+Provide a function netfs_make_node_alloc that allocates both nodes in
+a contiguous region.
+
+This reduces the memory allocation overhead when creating nodes.  It
+also makes the relation between node and netnode a simple offset
+calculation.  Provide two functions to compute the netnode address
+from the node address and vice-versa.
+
+Most notably, this makes implementing a cache on top of libnetfs
+easier.  Auxiliary data for the cache can be stored in the
+user-defined netnode, and the fat node can be used as the value.
+
+* libnetfs/make-node.c (init_node): Move initialization here.
+(netfs_make_node): Use init_node.
+(netfs_make_node_alloc): New function to allocate fat nodes.
+* libnetfs/netfs.h (netfs_make_node_alloc): New declaration.
+(netfs_node_netnode): Compute netnode address from node address.
+(netfs_netnode_node): And vice-versa.
+---
+ libnetfs/make-node.c | 29 +++++++++++++++++++++++------
+ libnetfs/netfs.h     | 22 ++++++++++++++++++++++
+ 2 files changed, 45 insertions(+), 6 deletions(-)
+
+diff --git a/libnetfs/make-node.c b/libnetfs/make-node.c
+index f20ada1..6bd8109 100644
+--- a/libnetfs/make-node.c
++++ b/libnetfs/make-node.c
+@@ -21,13 +21,9 @@
+ #include "netfs.h"
+ #include <hurd/fshelp.h>
+ 
+-struct node *
+-netfs_make_node (struct netnode *nn)
++static struct node *
++init_node (struct node *np, struct netnode *nn)
+ {
+-  struct node *np = malloc (sizeof (struct node));
+-  if (! np)
+-    return NULL;
+-  
+   np->nn = nn;
+ 
+   pthread_mutex_init (&np->lock, NULL);
+@@ -40,3 +36,24 @@ netfs_make_node (struct netnode *nn)
+   
+   return np;
+ }
++
++struct node *
++netfs_make_node (struct netnode *nn)
++{
++  struct node *np = malloc (sizeof (struct node));
++  if (! np)
++    return NULL;
++
++  return init_node (np, nn);
++}
++
++struct node *
++netfs_make_node_alloc (size_t size)
++{
++  struct node *np = malloc (sizeof (struct node) + size);
++
++  if (np == NULL)
++    return NULL;
++
++  return init_node (np, netfs_node_netnode (np));
++}
+diff --git a/libnetfs/netfs.h b/libnetfs/netfs.h
+index aef4a3d..e3c3b3e 100644
+--- a/libnetfs/netfs.h
++++ b/libnetfs/netfs.h
+@@ -372,6 +372,28 @@ extern int netfs_maxsymlinks;
+    If an error occurs, NULL is returned.  */
+ struct node *netfs_make_node (struct netnode *);
+ 
++/* Create a new node structure.  Also allocate SIZE bytes for the
++   netnode.  The address of the netnode can be obtained using
++   netfs_node_netnode.  The new node will have one hard reference and
++   no light references.  If an error occurs, NULL is returned.  */
++struct node *netfs_make_node_alloc (size_t size);
++
++/* Return the address of the netnode for NODE.  NODE must have been
++   allocated using netfs_make_node_alloc.  */
++static inline struct netnode *
++netfs_node_netnode (struct node *node)
++{
++  return (struct netnode *) ((char *) node + sizeof (struct node));
++}
++
++/* Return the address of the node for NETNODE.  NETNODE must have been
++   allocated using netfs_make_node_alloc.  */
++static inline struct node *
++netfs_netnode_node (struct netnode *netnode)
++{
++  return (struct node *) ((char *) netnode - sizeof (struct node));
++}
++
+ /* Whenever node->references is to be touched, this lock must be
+    held.  Cf. netfs_nrele, netfs_nput, netfs_nref and netfs_drop_node.  */
+ extern pthread_spinlock_t netfs_node_refcnt_lock;
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0003-trans-fakeroot-use-fat-nodes-to-simplify-the-node-ca.patch b/debian/patches/0003-trans-fakeroot-use-fat-nodes-to-simplify-the-node-ca.patch
new file mode 100644
index 00000000..2935ca95
--- /dev/null
+++ b/debian/patches/0003-trans-fakeroot-use-fat-nodes-to-simplify-the-node-ca.patch
@@ -0,0 +1,149 @@
+From 1179323768f5ee7533ec4d5088e462cda7622f44 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sun, 18 May 2014 13:45:14 +0200
+Subject: [PATCH 03/16] trans/fakeroot: use fat nodes to simplify the node
+ cache
+
+Previously, fakeroot stored netnodes in the hash table.  But we are
+not interested in a cache for netnodes, we need a node cache.  So
+fakeroot kept pointers to the associated node object in each netnode
+object.
+
+Use fat netfs nodes, which combine node and netnode objects.
+
+* trans/fakeroot.c (struct netnode): Remove np.
+(idport_ihash): Fix ihash location pointer offset.
+(new_node): Allocate fat nodes, store the node pointer in the hash
+table.
+(netfs_node_norefs): Adjust accordingly.
+(netfs_S_dir_lookup): Likewise.
+---
+ trans/fakeroot.c | 36 ++++++++++++------------------------
+ 1 file changed, 12 insertions(+), 24 deletions(-)
+
+diff --git a/trans/fakeroot.c b/trans/fakeroot.c
+index c4b95de..dd0124a 100644
+--- a/trans/fakeroot.c
++++ b/trans/fakeroot.c
+@@ -47,7 +47,6 @@ static auth_t fakeroot_auth_port;
+ 
+ struct netnode
+ {
+-  struct node *np;		/* our node */
+   hurd_ihash_locp_t idport_locp;/* easy removal pointer in idport ihash */
+   mach_port_t idport;		/* port from io_identity */
+   int openmodes;		/* O_READ | O_WRITE | O_EXEC */
+@@ -64,7 +63,8 @@ struct netnode
+ 
+ pthread_mutex_t idport_ihash_lock = PTHREAD_MUTEX_INITIALIZER;
+ struct hurd_ihash idport_ihash
+-  = HURD_IHASH_INITIALIZER (offsetof (struct netnode, idport_locp));
++= HURD_IHASH_INITIALIZER (sizeof (struct node)
++			  + offsetof (struct netnode, idport_locp));
+ 
+ 
+ /* Make a new virtual node.  Always consumes the ports.  If
+@@ -74,8 +74,9 @@ new_node (file_t file, mach_port_t idport, int locked, int openmodes,
+ 	  struct node **np)
+ {
+   error_t err;
+-  struct netnode *nn = calloc (1, sizeof *nn);
+-  if (nn == 0)
++  struct netnode *nn;
++  *np = netfs_make_node_alloc (sizeof *nn);
++  if (*np == 0)
+     {
+       mach_port_deallocate (mach_task_self (), file);
+       if (idport != MACH_PORT_NULL)
+@@ -84,6 +85,7 @@ new_node (file_t file, mach_port_t idport, int locked, int openmodes,
+ 	pthread_mutex_unlock (&idport_ihash_lock);
+       return ENOMEM;
+     }
++  nn = netfs_node_netnode (*np);
+   nn->file = file;
+   nn->openmodes = openmodes;
+   if (idport != MACH_PORT_NULL)
+@@ -97,35 +99,26 @@ new_node (file_t file, mach_port_t idport, int locked, int openmodes,
+       if (err)
+ 	{
+ 	  mach_port_deallocate (mach_task_self (), file);
+-	  free (nn);
++	  free (*np);
+ 	  return err;
+ 	}
+     }
+ 
+   if (!locked)
+     pthread_mutex_lock (&idport_ihash_lock);
+-  err = hurd_ihash_add (&idport_ihash, nn->idport, nn);
++  err = hurd_ihash_add (&idport_ihash, nn->idport, *np);
+   if (err)
+     goto lose;
+ 
+-  *np = nn->np = netfs_make_node (nn);
+-  if (*np == 0)
+-    {
+-      err = ENOMEM;
+-      goto lose_hash;
+-    }
+-
+   pthread_mutex_lock (&(*np)->lock);
+   pthread_mutex_unlock (&idport_ihash_lock);
+   return 0;
+ 
+- lose_hash:
+-  hurd_ihash_locp_remove (&idport_ihash, nn->idport_locp);
+  lose:
+   pthread_mutex_unlock (&idport_ihash_lock);
+   mach_port_deallocate (mach_task_self (), nn->idport);
+   mach_port_deallocate (mach_task_self (), file);
+-  free (nn);
++  free (*np);
+   return err;
+ }
+ 
+@@ -161,8 +154,6 @@ set_faked_attribute (struct node *np, unsigned int faked)
+ void
+ netfs_node_norefs (struct node *np)
+ {
+-  assert (np->nn->np == np);
+-
+   pthread_mutex_unlock (&np->lock);
+   pthread_spin_unlock (&netfs_node_refcnt_lock);
+ 
+@@ -172,7 +163,6 @@ netfs_node_norefs (struct node *np)
+ 
+   mach_port_deallocate (mach_task_self (), np->nn->file);
+   mach_port_deallocate (mach_task_self (), np->nn->idport);
+-  free (np->nn);
+   free (np);
+ 
+   pthread_spin_lock (&netfs_node_refcnt_lock);
+@@ -358,13 +348,12 @@ netfs_S_dir_lookup (struct protid *diruser,
+      refcount lock so that, if a node is found, its reference counter cannot
+      drop to 0 before we get our own reference.  */
+   pthread_spin_lock (&netfs_node_refcnt_lock);
+-  struct netnode *nn = hurd_ihash_find (&idport_ihash, idport);
+-  if (nn != NULL)
++  np = hurd_ihash_find (&idport_ihash, idport);
++  if (np != NULL)
+     {
+-      assert (nn->np->nn == nn);
+       /* We already know about this node.  */
+ 
+-      if (nn->np->references == 0)
++      if (np->references == 0)
+ 	{
+ 	  /* But it might be in the process of being released.  If so,
+ 	     unlock the hash table to give the node a chance to actually
+@@ -376,7 +365,6 @@ netfs_S_dir_lookup (struct protid *diruser,
+ 	}
+ 
+       /* Otherwise, reference it right away.  */
+-      np = nn->np;
+       np->references++;
+       pthread_spin_unlock (&netfs_node_refcnt_lock);
+ 
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0004-trans-fakeroot-use-netfs_node_netnode-instead-of-np-.patch b/debian/patches/0004-trans-fakeroot-use-netfs_node_netnode-instead-of-np-.patch
new file mode 100644
index 00000000..0b2e54ab
--- /dev/null
+++ b/debian/patches/0004-trans-fakeroot-use-netfs_node_netnode-instead-of-np-.patch
@@ -0,0 +1,386 @@
+From 9c09930aa4461878bf93bb7640f5e877f8f93a93 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sun, 18 May 2014 14:06:30 +0200
+Subject: [PATCH 04/16] trans/fakeroot: use netfs_node_netnode instead of
+ np->nn
+
+When using fat nodes, expressions of the form E->nn can be rewritten
+as netfs_node_netnode (E).  This is much faster as it only involves a
+offset calculation.  For reference, I used the following semantic
+patch to create the patch:
+
+@@
+expression E;
+@@
+
+- E->nn
++ netfs_node_netnode (E)
+
+* trans/fakeroot.c: Use netfs_node_netnode instead of np->nn.
+---
+ trans/fakeroot.c | 99 ++++++++++++++++++++++++++++++--------------------------
+ 1 file changed, 53 insertions(+), 46 deletions(-)
+
+diff --git a/trans/fakeroot.c b/trans/fakeroot.c
+index dd0124a..d3addc1 100644
+--- a/trans/fakeroot.c
++++ b/trans/fakeroot.c
+@@ -125,7 +125,7 @@ new_node (file_t file, mach_port_t idport, int locked, int openmodes,
+ static void
+ set_default_attributes (struct node *np)
+ {
+-  np->nn->faked = FAKE_UID | FAKE_GID | FAKE_DEFAULT;
++  netfs_node_netnode (np)->faked = FAKE_UID | FAKE_GID | FAKE_DEFAULT;
+   np->nn_stat.st_uid = 0;
+   np->nn_stat.st_gid = 0;
+ }
+@@ -133,9 +133,9 @@ set_default_attributes (struct node *np)
+ static void
+ set_faked_attribute (struct node *np, unsigned int faked)
+ {
+-  np->nn->faked |= faked;
++  netfs_node_netnode (np)->faked |= faked;
+ 
+-  if (np->nn->faked & FAKE_DEFAULT)
++  if (netfs_node_netnode (np)->faked & FAKE_DEFAULT)
+     {
+       /* Now that the node has non-default faked attributes, they have to be
+ 	 retained for future accesses.  Account for the hash table reference.
+@@ -146,7 +146,7 @@ set_faked_attribute (struct node *np, unsigned int faked)
+ 	 easy enough if it's ever needed, although scalability could be
+ 	 improved.  */
+       netfs_nref (np);
+-      np->nn->faked &= ~FAKE_DEFAULT;
++      netfs_node_netnode (np)->faked &= ~FAKE_DEFAULT;
+     }
+ }
+ 
+@@ -158,11 +158,11 @@ netfs_node_norefs (struct node *np)
+   pthread_spin_unlock (&netfs_node_refcnt_lock);
+ 
+   pthread_mutex_lock (&idport_ihash_lock);
+-  hurd_ihash_locp_remove (&idport_ihash, np->nn->idport_locp);
++  hurd_ihash_locp_remove (&idport_ihash, netfs_node_netnode (np)->idport_locp);
+   pthread_mutex_unlock (&idport_ihash_lock);
+ 
+-  mach_port_deallocate (mach_task_self (), np->nn->file);
+-  mach_port_deallocate (mach_task_self (), np->nn->idport);
++  mach_port_deallocate (mach_task_self (), netfs_node_netnode (np)->file);
++  mach_port_deallocate (mach_task_self (), netfs_node_netnode (np)->idport);
+   free (np);
+ 
+   pthread_spin_lock (&netfs_node_refcnt_lock);
+@@ -245,7 +245,8 @@ error_t
+ netfs_check_open_permissions (struct iouser *user, struct node *np,
+ 			      int flags, int newnode)
+ {
+-  return check_openmodes (np->nn, flags & (O_RDWR|O_EXEC), MACH_PORT_NULL);
++  return check_openmodes (netfs_node_netnode (np),
++			  flags & (O_RDWR|O_EXEC), MACH_PORT_NULL);
+ }
+ 
+ error_t
+@@ -271,12 +272,12 @@ netfs_S_dir_lookup (struct protid *diruser,
+ 
+   dnp = diruser->po->np;
+ 
+-  mach_port_t dir = dnp->nn->file;
++  mach_port_t dir = netfs_node_netnode (dnp)->file;
+  redo_lookup:
+   err = dir_lookup (dir, filename,
+ 		    flags & (O_NOLINK|O_RDWR|O_EXEC|O_CREAT|O_EXCL|O_NONBLOCK),
+ 		    mode, do_retry, retry_name, &file);
+-  if (dir != dnp->nn->file)
++  if (dir != netfs_node_netnode (dnp)->file)
+     mach_port_deallocate (mach_task_self (), dir);
+   if (err)
+     return err;
+@@ -380,7 +381,8 @@ netfs_S_dir_lookup (struct protid *diruser,
+ 	  pthread_mutex_unlock (&dnp->lock);
+ 	}
+ 
+-      err = check_openmodes (np->nn, (flags & (O_RDWR|O_EXEC)), file);
++      err = check_openmodes (netfs_node_netnode (np),
++			     (flags & (O_RDWR|O_EXEC)), file);
+       pthread_mutex_unlock (&idport_ihash_lock);
+     }
+   else
+@@ -448,17 +450,17 @@ error_t
+ netfs_validate_stat (struct node *np, struct iouser *cred)
+ {
+   struct stat st;
+-  error_t err = io_stat (np->nn->file, &st);
++  error_t err = io_stat (netfs_node_netnode (np)->file, &st);
+   if (err)
+     return err;
+ 
+-  if (np->nn->faked & FAKE_UID)
++  if (netfs_node_netnode (np)->faked & FAKE_UID)
+     st.st_uid = np->nn_stat.st_uid;
+-  if (np->nn->faked & FAKE_GID)
++  if (netfs_node_netnode (np)->faked & FAKE_GID)
+     st.st_gid = np->nn_stat.st_gid;
+-  if (np->nn->faked & FAKE_AUTHOR)
++  if (netfs_node_netnode (np)->faked & FAKE_AUTHOR)
+     st.st_author = np->nn_stat.st_author;
+-  if (np->nn->faked & FAKE_MODE)
++  if (netfs_node_netnode (np)->faked & FAKE_MODE)
+     st.st_mode = np->nn_stat.st_mode;
+ 
+   np->nn_stat = st;
+@@ -518,7 +520,7 @@ netfs_attempt_chmod (struct iouser *cred, struct node *np, mode_t mode)
+ 
+   /* We don't bother with error checking since the fake mode change should
+      always succeed--worst case a later open will get EACCES.  */
+-  (void) file_chmod (np->nn->file, mode);
++  (void) file_chmod (netfs_node_netnode (np)->file, mode);
+   set_faked_attribute (np, FAKE_MODE);
+   np->nn_stat.st_mode = mode;
+   return 0;
+@@ -533,7 +535,7 @@ netfs_attempt_mksymlink (struct iouser *cred, struct node *np, char *name)
+   char trans[sizeof _HURD_SYMLINK + namelen];
+   memcpy (trans, _HURD_SYMLINK, sizeof _HURD_SYMLINK);
+   memcpy (&trans[sizeof _HURD_SYMLINK], name, namelen);
+-  return file_set_translator (np->nn->file,
++  return file_set_translator (netfs_node_netnode (np)->file,
+ 			      FS_TRANS_EXCL|FS_TRANS_SET,
+ 			      FS_TRANS_EXCL|FS_TRANS_SET, 0,
+ 			      trans, sizeof trans,
+@@ -552,7 +554,7 @@ netfs_attempt_mkdev (struct iouser *cred, struct node *np,
+     return ENOMEM;
+   else
+     {
+-      error_t err = file_set_translator (np->nn->file,
++      error_t err = file_set_translator (netfs_node_netnode (np)->file,
+ 					 FS_TRANS_EXCL|FS_TRANS_SET,
+ 					 FS_TRANS_EXCL|FS_TRANS_SET, 0,
+ 					 trans, translen + 1,
+@@ -566,7 +568,7 @@ netfs_attempt_mkdev (struct iouser *cred, struct node *np,
+ error_t
+ netfs_attempt_chflags (struct iouser *cred, struct node *np, int flags)
+ {
+-  return file_chflags (np->nn->file, flags);
++  return file_chflags (netfs_node_netnode (np)->file, flags);
+ }
+ 
+ error_t
+@@ -592,25 +594,25 @@ netfs_attempt_utimes (struct iouser *cred, struct node *np,
+   else
+     m.tv.tv_sec = m.tv.tv_usec = -1;
+ 
+-  return file_utimes (np->nn->file, a.tvt, m.tvt);
++  return file_utimes (netfs_node_netnode (np)->file, a.tvt, m.tvt);
+ }
+ 
+ error_t
+ netfs_attempt_set_size (struct iouser *cred, struct node *np, off_t size)
+ {
+-  return file_set_size (np->nn->file, size);
++  return file_set_size (netfs_node_netnode (np)->file, size);
+ }
+ 
+ error_t
+ netfs_attempt_statfs (struct iouser *cred, struct node *np, struct statfs *st)
+ {
+-  return file_statfs (np->nn->file, st);
++  return file_statfs (netfs_node_netnode (np)->file, st);
+ }
+ 
+ error_t
+ netfs_attempt_sync (struct iouser *cred, struct node *np, int wait)
+ {
+-  return file_sync (np->nn->file, wait, 0);
++  return file_sync (netfs_node_netnode (np)->file, wait, 0);
+ }
+ 
+ error_t
+@@ -623,7 +625,7 @@ error_t
+ netfs_attempt_mkdir (struct iouser *user, struct node *dir,
+ 		     char *name, mode_t mode)
+ {
+-  return dir_mkdir (dir->nn->file, name, mode | S_IRWXU);
++  return dir_mkdir (netfs_node_netnode (dir)->file, name, mode | S_IRWXU);
+ }
+ 
+ 
+@@ -635,7 +637,7 @@ netfs_attempt_mkdir (struct iouser *user, struct node *dir,
+ error_t
+ netfs_attempt_unlink (struct iouser *user, struct node *dir, char *name)
+ {
+-  return dir_unlink (dir->nn->file, name);
++  return dir_unlink (netfs_node_netnode (dir)->file, name);
+ }
+ 
+ error_t
+@@ -643,22 +645,22 @@ netfs_attempt_rename (struct iouser *user, struct node *fromdir,
+ 		      char *fromname, struct node *todir,
+ 		      char *toname, int excl)
+ {
+-  return dir_rename (fromdir->nn->file, fromname,
+-		     todir->nn->file, toname, excl);
++  return dir_rename (netfs_node_netnode (fromdir)->file, fromname,
++		     netfs_node_netnode (todir)->file, toname, excl);
+ }
+ 
+ error_t
+ netfs_attempt_rmdir (struct iouser *user,
+ 		     struct node *dir, char *name)
+ {
+-  return dir_rmdir (dir->nn->file, name);
++  return dir_rmdir (netfs_node_netnode (dir)->file, name);
+ }
+ 
+ error_t
+ netfs_attempt_link (struct iouser *user, struct node *dir,
+ 		    struct node *file, char *name, int excl)
+ {
+-  return dir_link (dir->nn->file, file->nn->file, name, excl);
++  return dir_link (netfs_node_netnode (dir)->file, netfs_node_netnode (file)->file, name, excl);
+ }
+ 
+ error_t
+@@ -666,7 +668,7 @@ netfs_attempt_mkfile (struct iouser *user, struct node *dir,
+ 		      mode_t mode, struct node **np)
+ {
+   file_t newfile;
+-  error_t err = dir_mkfile (dir->nn->file, O_RDWR|O_EXEC,
++  error_t err = dir_mkfile (netfs_node_netnode (dir)->file, O_RDWR|O_EXEC,
+ 			    real_from_fake_mode (mode), &newfile);
+   pthread_mutex_unlock (&dir->lock);
+   if (err == 0)
+@@ -682,7 +684,8 @@ netfs_attempt_readlink (struct iouser *user, struct node *np, char *buf)
+   char transbuf[sizeof _HURD_SYMLINK + np->nn_stat.st_size + 1];
+   char *trans = transbuf;
+   size_t translen = sizeof transbuf;
+-  error_t err = file_get_translator (np->nn->file, &trans, &translen);
++  error_t err = file_get_translator (netfs_node_netnode (np)->file,
++				     &trans, &translen);
+   if (err == 0)
+     {
+       if (translen < sizeof _HURD_SYMLINK
+@@ -705,7 +708,8 @@ netfs_attempt_read (struct iouser *cred, struct node *np,
+ 		    off_t offset, size_t *len, void *data)
+ {
+   char *buf = data;
+-  error_t err = io_read (np->nn->file, &buf, len, offset, *len);
++  error_t err = io_read (netfs_node_netnode (np)->file,
++			 &buf, len, offset, *len);
+   if (err == 0 && buf != data)
+     {
+       memcpy (data, buf, *len);
+@@ -718,7 +722,7 @@ error_t
+ netfs_attempt_write (struct iouser *cred, struct node *np,
+ 		     off_t offset, size_t *len, void *data)
+ {
+-  return io_write (np->nn->file, data, *len, offset, len);
++  return io_write (netfs_node_netnode (np)->file, data, *len, offset, len);
+ }
+ 
+ error_t
+@@ -734,7 +738,7 @@ netfs_get_dirents (struct iouser *cred, struct node *dir,
+ 		   mach_msg_type_number_t *datacnt,
+ 		   vm_size_t bufsize, int *amt)
+ {
+-  return dir_readdir (dir->nn->file, data, datacnt,
++  return dir_readdir (netfs_node_netnode (dir)->file, data, datacnt,
+ 		      entry, nentries, bufsize, amt);
+ }
+ 
+@@ -752,7 +756,7 @@ netfs_file_get_storage_info (struct iouser *cred,
+ 			     mach_msg_type_number_t *data_len)
+ {
+   *ports_type = MACH_MSG_TYPE_MOVE_SEND;
+-  return file_get_storage_info (np->nn->file,
++  return file_get_storage_info (netfs_node_netnode (np)->file,
+ 				ports, num_ports,
+ 				ints, num_ints,
+ 				offsets, num_offsets,
+@@ -785,8 +789,9 @@ netfs_S_file_exec (struct protid *user,
+     return EOPNOTSUPP;
+ 
+   pthread_mutex_lock (&user->po->np->lock);
+-  err = check_openmodes (user->po->np->nn, O_EXEC, MACH_PORT_NULL);
+-  file = user->po->np->nn->file;
++  err = check_openmodes (netfs_node_netnode (user->po->np),
++			 O_EXEC, MACH_PORT_NULL);
++  file = netfs_node_netnode (user->po->np)->file;
+   if (!err)
+     err = mach_port_mod_refs (mach_task_self (),
+ 			      file, MACH_PORT_RIGHT_SEND, 1);
+@@ -796,7 +801,8 @@ netfs_S_file_exec (struct protid *user,
+     {
+       /* We cannot use MACH_MSG_TYPE_MOVE_SEND because we might need to
+ 	 retry an interrupted call that would have consumed the rights.  */
+-      err = file_exec (user->po->np->nn->file, task, flags, argv, argvlen,
++      err = file_exec (netfs_node_netnode (user->po->np)->file,
++		       task, flags, argv, argvlen,
+ 		       envp, envplen, fds, MACH_MSG_TYPE_COPY_SEND, fdslen,
+ 		       portarray, MACH_MSG_TYPE_COPY_SEND, portarraylen,
+ 		       intarray, intarraylen, deallocnames, deallocnameslen,
+@@ -828,7 +834,7 @@ netfs_S_io_map (struct protid *user,
+   *rdobjtype = *wrobjtype = MACH_MSG_TYPE_MOVE_SEND;
+ 
+   pthread_mutex_lock (&user->po->np->lock);
+-  err = io_map (user->po->np->nn->file, rdobj, wrobj);
++  err = io_map (netfs_node_netnode (user->po->np)->file, rdobj, wrobj);
+   pthread_mutex_unlock (&user->po->np->lock);
+   return err;
+ }
+@@ -845,7 +851,7 @@ netfs_S_io_map_cntl (struct protid *user,
+   *objtype = MACH_MSG_TYPE_MOVE_SEND;
+ 
+   pthread_mutex_lock (&user->po->np->lock);
+-  err = io_map_cntl (user->po->np->nn->file, obj);
++  err = io_map_cntl (netfs_node_netnode (user->po->np)->file, obj);
+   pthread_mutex_unlock (&user->po->np->lock);
+   return err;
+ }
+@@ -866,7 +872,8 @@ netfs_S_io_identity (struct protid *user,
+   *idtype = *fsystype = MACH_MSG_TYPE_MOVE_SEND;
+ 
+   pthread_mutex_lock (&user->po->np->lock);
+-  err = io_identity (user->po->np->nn->file, id, fsys, fileno);
++  err = io_identity (netfs_node_netnode (user->po->np)->file,
++		     id, fsys, fileno);
+   pthread_mutex_unlock (&user->po->np->lock);
+   return err;
+ }
+@@ -881,7 +888,7 @@ netfs_S_##name (struct protid *user)		\
+     return EOPNOTSUPP;				\
+ 						\
+   pthread_mutex_lock (&user->po->np->lock);	\
+-  err = name (user->po->np->nn->file);		\
++  err = name (netfs_node_netnode (user->po->np)->file);		\
+   pthread_mutex_unlock (&user->po->np->lock);	\
+   return err;					\
+ }
+@@ -903,7 +910,7 @@ netfs_S_io_prenotify (struct protid *user,
+     return EOPNOTSUPP;
+ 
+   pthread_mutex_lock (&user->po->np->lock);
+-  err = io_prenotify (user->po->np->nn->file, start, stop);
++  err = io_prenotify (netfs_node_netnode (user->po->np)->file, start, stop);
+   pthread_mutex_unlock (&user->po->np->lock);
+   return err;
+ }
+@@ -918,7 +925,7 @@ netfs_S_io_postnotify (struct protid *user,
+     return EOPNOTSUPP;
+ 
+   pthread_mutex_lock (&user->po->np->lock);
+-  err = io_postnotify (user->po->np->nn->file, start, stop);
++  err = io_postnotify (netfs_node_netnode (user->po->np)->file, start, stop);
+   pthread_mutex_unlock (&user->po->np->lock);
+   return err;
+ }
+@@ -961,7 +968,7 @@ netfs_demuxer (mach_msg_header_t *inp,
+ 	    | MACH_MSGH_BITS (MACH_MSG_TYPE_COPY_SEND,
+ 			      MACH_MSGH_BITS_REMOTE (inp->msgh_bits));
+ 	  inp->msgh_local_port = inp->msgh_remote_port;	/* reply port */
+-	  inp->msgh_remote_port = cred->po->np->nn->file;
++	  inp->msgh_remote_port = netfs_node_netnode (cred->po->np)->file;
+ 	  err = mach_msg (inp, MACH_SEND_MSG, inp->msgh_size, 0,
+ 			  MACH_PORT_NULL, MACH_MSG_TIMEOUT_NONE,
+ 			  MACH_PORT_NULL);
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0005-include-add-lock-less-reference-counting-primitives.patch b/debian/patches/0005-include-add-lock-less-reference-counting-primitives.patch
new file mode 100644
index 00000000..acecdf74
--- /dev/null
+++ b/debian/patches/0005-include-add-lock-less-reference-counting-primitives.patch
@@ -0,0 +1,283 @@
+From e83aa1db431019801a055ea0280bc7468e49cbaf Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 6 May 2014 19:52:04 +0200
+Subject: [PATCH 05/16] include: add lock-less reference counting primitives
+
+* include/refcount.h: New file.
+---
+ include/refcount.h | 263 +++++++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 263 insertions(+)
+ create mode 100644 include/refcount.h
+
+diff --git a/include/refcount.h b/include/refcount.h
+new file mode 100644
+index 0000000..5c3302d
+--- /dev/null
++++ b/include/refcount.h
+@@ -0,0 +1,263 @@
++/* Lock-less reference counting primitives
++
++   Copyright (C) 2014 Free Software Foundation, Inc.
++
++   Written by Justus Winter <4winter@informatik.uni-hamburg.de>
++
++   This file is part of the GNU Hurd.
++
++   The GNU Hurd is free software; you can redistribute it and/or
++   modify it under the terms of the GNU General Public License as
++   published by the Free Software Foundation; either version 2, or (at
++   your option) any later version.
++
++   The GNU Hurd is distributed in the hope that it will be useful, but
++   WITHOUT ANY WARRANTY; without even the implied warranty of
++   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++   General Public License for more details.
++
++   You should have received a copy of the GNU General Public License
++   along with the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
++
++#ifndef _HURD_REFCOUNT_H_
++#define _HURD_REFCOUNT_H_
++
++#include <assert.h>
++#include <limits.h>
++#include <stdint.h>
++
++/* Simple reference counting.  */
++
++/* An opaque type.  You must not access these values directly.  */
++typedef unsigned int refcount_t;
++
++/* Initialize REF with REFERENCES.  */
++static inline void
++refcount_init (refcount_t *ref, unsigned int references)
++{
++  *ref = references;
++}
++
++/* Increment REF.  Return the result of the operation.  This function
++   uses atomic operations.  It is not required to serialize calls to
++   this function.  */
++static inline unsigned int
++refcount_ref (refcount_t *ref)
++{
++  unsigned int r;
++  r = __atomic_add_fetch (ref, 1, __ATOMIC_RELAXED);
++  assert (r != UINT_MAX || !"refcount overflowed!");
++  return r;
++}
++
++/* Decrement REF.  Return the result of the operation.  This function
++   uses atomic operations.  It is not required to serialize calls to
++   this function.  */
++static inline unsigned int
++refcount_deref (refcount_t *ref)
++{
++  unsigned int r;
++  r = __atomic_sub_fetch (ref, 1, __ATOMIC_RELAXED);
++  assert (r != UINT_MAX || !"refcount underflowed!");
++  return r;
++}
++
++/* Return REF.  This function uses atomic operations.  It is not
++   required to serialize calls to this function.  */
++static inline unsigned int
++refcount_references (refcount_t *ref)
++{
++  return __atomic_load_n (ref, __ATOMIC_RELAXED);
++}
++
++/* Reference counting with weak references.  */
++
++/* An opaque type.  You must not access these values directly.  */
++typedef union _references refcounts_t;
++
++/* Instead, the functions manipulating refcounts_t values write the
++   results into this kind of objects.  */
++struct references {
++  /* We chose the layout of this struct so that when it is used in the
++     union _references, the hard reference counts occupy the least
++     significant bits.  We rely on this layout for atomic promotion
++     and demotion of references.  See refcounts_promote and
++     refcounts_demote for details.  */
++#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
++  uint32_t hard;
++  uint32_t weak;
++#else
++  uint32_t weak;
++  uint32_t hard;
++#endif
++};
++
++/* We use a union to convert struct reference values to uint64_t which
++   we can manipulate atomically.  While this behavior is not
++   guaranteed by the C standard, it is supported by all major
++   compilers.  */
++union _references {
++  struct references references;
++  uint64_t value;
++};
++
++/* Initialize REF with HARD and WEAK references.  */
++static inline void
++refcounts_init (refcounts_t *ref, uint32_t hard, uint32_t weak)
++{
++  ref->references = (struct references) { .hard = hard, .weak = weak };
++}
++
++/* Increment the hard reference count of REF.  If RESULT is not NULL,
++   the result of the operation is written there.  This function uses
++   atomic operations.  It is not required to serialize calls to this
++   function.  */
++static inline void
++refcounts_ref (refcounts_t *ref, struct references *result)
++{
++  const union _references op = { .references = { .hard = 1 } };
++  union _references r;
++  r.value = __atomic_add_fetch (&ref->value, op.value, __ATOMIC_RELAXED);
++  assert (r.references.hard != UINT32_MAX || !"refcount overflowed!");
++  if (result)
++    *result = r.references;
++}
++
++/* Decrement the hard reference count of REF.  If RESULT is not NULL,
++   the result of the operation is written there.  This function uses
++   atomic operations.  It is not required to serialize calls to this
++   function.  */
++static inline void
++refcounts_deref (refcounts_t *ref, struct references *result)
++{
++  const union _references op = { .references = { .hard = 1 } };
++  union _references r;
++  r.value = __atomic_sub_fetch (&ref->value, op.value, __ATOMIC_RELAXED);
++  assert (r.references.hard != UINT32_MAX || !"refcount underflowed!");
++  if (result)
++    *result = r.references;
++}
++
++/* Promote a weak reference to a hard reference.  If RESULT is not
++   NULL, the result of the operation is written there.  This function
++   uses atomic operations.  It is not required to serialize calls to
++   this function.  */
++static inline void
++refcounts_promote (refcounts_t *ref, struct references *result)
++{
++  /* To promote a weak reference, we need to atomically subtract 1
++     from the weak reference count, and add 1 to the hard reference
++     count.
++
++     We can subtract by 1 by adding the two's complement of 1 = ~0 to
++     a fixed-width value, discarding the overflow.
++
++     We do the same in our uint64_t value, but we have chosen the
++     layout of struct references so that when it is used in the union
++     _references, the weak reference counts occupy the most
++     significant bits.  When we add ~0 to the weak references, the
++     overflow will be discarded as unsigned arithmetic is modulo 2^n.
++     So we just add a hard reference.  In combination, this is the
++     desired operation.  */
++  const union _references op =
++    { .references = { .weak = ~0, .hard = 1} };
++  union _references r;
++  r.value = __atomic_add_fetch (&ref->value, op.value, __ATOMIC_RELAXED);
++  assert (r.references.hard != UINT32_MAX || !"refcount overflowed!");
++  assert (r.references.weak != UINT32_MAX || !"refcount underflowed!");
++  if (result)
++    *result = r.references;
++}
++
++/* Demote a hard reference to a weak reference.  If RESULT is not
++   NULL, the result of the operation is written there.  This function
++   uses atomic operations.  It is not required to serialize calls to
++   this function.  */
++static inline void
++refcounts_demote (refcounts_t *ref, struct references *result)
++{
++  /* To demote a hard reference, we need to atomically subtract 1 from
++     the hard reference count, and add 1 to the weak reference count.
++
++     We can subtract by 1 by adding the two's complement of 1 = ~0 to
++     a fixed-width value, discarding the overflow.
++
++     We do the same in our uint64_t value, but we have chosen the
++     layout of struct references so that when it is used in the union
++     _references, the hard reference counts occupy the least
++     significant bits.  When we add ~0 to the hard references, it will
++     overflow into the weak references.  This is the desired
++     operation.  */
++  const union _references op = { .references = { .hard = ~0 } };
++  union _references r;
++  r.value = __atomic_add_fetch (&ref->value, op.value, __ATOMIC_RELAXED);
++  assert (r.references.hard != UINT32_MAX || !"refcount underflowed!");
++  assert (r.references.weak != UINT32_MAX || !"refcount overflowed!");
++  if (result)
++    *result = r.references;
++}
++
++/* Increment the weak reference count of REF.  If RESULT is not NULL,
++   the result of the operation is written there.  This function uses
++   atomic operations.  It is not required to serialize calls to this
++   function.  */
++static inline void
++refcounts_ref_weak (refcounts_t *ref, struct references *result)
++{
++  const union _references op = { .references = { .weak = 1 } };
++  union _references r;
++  r.value = __atomic_add_fetch (&ref->value, op.value, __ATOMIC_RELAXED);
++  assert (r.references.weak != UINT32_MAX || !"refcount overflowed!");
++  if (result)
++    *result = r.references;
++}
++
++/* Decrement the weak reference count of REF.  If RESULT is not NULL,
++   the result of the operation is written there.  This function uses
++   atomic operations.  It is not required to serialize calls to this
++   function.  */
++static inline void
++refcounts_deref_weak (refcounts_t *ref, struct references *result)
++{
++  const union _references op = { .references = { .weak = 1 } };
++  union _references r;
++  r.value = __atomic_sub_fetch (&ref->value, op.value, __ATOMIC_RELAXED);
++  assert (r.references.weak != UINT32_MAX || !"refcount underflowed!");
++  if (result)
++    *result = r.references;
++}
++
++/* Store the current reference counts of REF in RESULT.  This function
++   uses atomic operations.  It is not required to serialize calls to
++   this function.  */
++static inline void
++refcounts_references (refcounts_t *ref, struct references *result)
++{
++  union _references r;
++  r.value =__atomic_load_n (&ref->value, __ATOMIC_RELAXED);
++  *result = r.references;
++}
++
++/* Return the hard reference count of REF.  This function uses atomic
++   operations.  It is not required to serialize calls to this
++   function.  */
++static inline uint32_t
++refcounts_hard_references (refcounts_t *ref)
++{
++  struct references result;
++  refcounts_references (ref, &result);
++  return result.hard;
++}
++
++/* Return the weak reference count of REF.  This function uses atomic
++   operations.  It is not required to serialize calls to this
++   function.  */
++static inline uint32_t
++refcounts_weak_references (refcounts_t *ref)
++{
++  struct references result;
++  refcounts_references (ref, &result);
++  return result.weak;
++}
++
++#endif /* _HURD_REFCOUNT_H_ */
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0006-libdiskfs-lock-less-reference-counting-for-peropen-o.patch b/debian/patches/0006-libdiskfs-lock-less-reference-counting-for-peropen-o.patch
new file mode 100644
index 00000000..7bf7f64c
--- /dev/null
+++ b/debian/patches/0006-libdiskfs-lock-less-reference-counting-for-peropen-o.patch
@@ -0,0 +1,143 @@
+From d58f0ac175e0506a9e76e4197497be20337e444d Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 6 May 2014 18:58:10 +0200
+Subject: [PATCH 06/16] libdiskfs: lock-less reference counting for peropen
+ objects
+
+* libdiskfs/diskfs.h (struct peropen): Use refcount_t for field refcnt.
+* libdiskfs/peropen-make.c (diskfs_make_peropen): Initialize refcnt.
+* libdiskfs/peropen-rele.c (diskfs_release_peropen): Adjust accordingly.
+* libdiskfs/protid-make.c (diskfs_start_protid): Likewise.  Also, the
+node must no longer be locked, adjust comment accordingly.
+(diskfs_create_protid): Likewise.
+---
+ libdiskfs/diskfs.h       |  7 ++++---
+ libdiskfs/peropen-make.c |  2 +-
+ libdiskfs/peropen-rele.c | 21 ++++++++++-----------
+ libdiskfs/protid-make.c  |  8 ++++----
+ 4 files changed, 19 insertions(+), 19 deletions(-)
+
+diff --git a/libdiskfs/diskfs.h b/libdiskfs/diskfs.h
+index a3f860d..acd1910 100644
+--- a/libdiskfs/diskfs.h
++++ b/libdiskfs/diskfs.h
+@@ -28,6 +28,7 @@
+ #include <hurd/iohelp.h>
+ #include <idvec.h>
+ #include <features.h>
++#include <refcount.h>
+ 
+ #ifdef DISKFS_DEFINE_EXTERN_INLINE
+ #define DISKFS_EXTERN_INLINE
+@@ -57,7 +58,7 @@ struct peropen
+ {
+   int filepointer;
+   int lock_status;
+-  int refcnt;
++  refcount_t refcnt;
+   int openstat;
+ 
+   struct node *np;
+@@ -817,12 +818,12 @@ diskfs_create_node (struct node *dir, const char *name, mode_t mode,
+ 		    struct dirstat *ds);
+ 
+ /* Create and return a protid for an existing peropen PO in CRED,
+-   referring to user USER.  The node PO->np must be locked. */
++   referring to user USER.  */
+ error_t diskfs_create_protid (struct peropen *po, struct iouser *user,
+ 			      struct protid **cred);
+ 
+ /* Build and return in CRED a protid which has no user identification, for
+-   peropen PO.  The node PO->np must be locked.  */
++   peropen PO.  */
+ error_t diskfs_start_protid (struct peropen *po, struct protid **cred);
+ 
+ /* Finish building protid CRED started with diskfs_start_protid;
+diff --git a/libdiskfs/peropen-make.c b/libdiskfs/peropen-make.c
+index eba037f..6d5ca01 100644
+--- a/libdiskfs/peropen-make.c
++++ b/libdiskfs/peropen-make.c
+@@ -31,7 +31,7 @@ diskfs_make_peropen (struct node *np, int flags, struct peropen *context,
+ 
+   po->filepointer = 0;
+   po->lock_status = LOCK_UN;
+-  po->refcnt = 0;
++  refcount_init (&po->refcnt, 0);
+   po->openstat = flags;
+   po->np = np;
+   po->path = NULL;
+diff --git a/libdiskfs/peropen-rele.c b/libdiskfs/peropen-rele.c
+index d3f7492..877137b 100644
+--- a/libdiskfs/peropen-rele.c
++++ b/libdiskfs/peropen-rele.c
+@@ -22,13 +22,8 @@
+ void
+ diskfs_release_peropen (struct peropen *po)
+ {
+-  pthread_mutex_lock (&po->np->lock);
+-
+-  if (--po->refcnt)
+-    {
+-      pthread_mutex_unlock (&po->np->lock);
+-      return;
+-    }
++  if (refcount_deref (&po->refcnt) > 0)
++    return;
+ 
+   if (po->root_parent)
+     mach_port_deallocate (mach_task_self (), po->root_parent);
+@@ -40,10 +35,14 @@ diskfs_release_peropen (struct peropen *po)
+     mach_port_deallocate (mach_task_self (), po->shadow_root_parent);
+ 
+   if (po->lock_status != LOCK_UN)
+-    fshelp_acquire_lock (&po->np->userlock, &po->lock_status,
+-			 &po->np->lock, LOCK_UN);
+-
+-  diskfs_nput (po->np);
++    {
++      pthread_mutex_lock (&po->np->lock);
++      fshelp_acquire_lock (&po->np->userlock, &po->lock_status,
++                           &po->np->lock, LOCK_UN);
++      diskfs_nput (po->np);
++    }
++  else
++    diskfs_nrele (po->np);
+ 
+   free (po->path);
+   free (po);
+diff --git a/libdiskfs/protid-make.c b/libdiskfs/protid-make.c
+index b39b92a..22aaa2e 100644
+--- a/libdiskfs/protid-make.c
++++ b/libdiskfs/protid-make.c
+@@ -20,7 +20,7 @@
+ #include <assert.h>
+ 
+ /* Build and return in CRED a protid which has no user identification, for
+-   peropen PO.  The node PO->np must be locked.  */
++   peropen PO.  */
+ error_t
+ diskfs_start_protid (struct peropen *po, struct protid **cred)
+ {
+@@ -29,7 +29,7 @@ diskfs_start_protid (struct peropen *po, struct protid **cred)
+ 				 sizeof (struct protid), cred);
+   if (! err)
+     {
+-      po->refcnt++;
++      refcount_ref (&po->refcnt);
+       (*cred)->po = po;
+       (*cred)->shared_object = MACH_PORT_NULL;
+       (*cred)->mapped = 0;
+@@ -55,8 +55,8 @@ diskfs_finish_protid (struct protid *cred, struct iouser *user)
+   assert_perror (err);
+ }
+ 
+-/* Create and return a protid for an existing peropen PO in CRED for USER.
+-   The node PO->np must be locked. */
++/* Create and return a protid for an existing peropen PO in CRED for
++   USER.  */
+ error_t
+ diskfs_create_protid (struct peropen *po, struct iouser *user,
+ 		      struct protid **cred)
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0007-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch b/debian/patches/0007-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch
new file mode 100644
index 00000000..38efa96c
--- /dev/null
+++ b/debian/patches/0007-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch
@@ -0,0 +1,172 @@
+From 1e2adfb6aea06217b5db7baecb86205a3942f5fa Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 6 May 2014 19:07:13 +0200
+Subject: [PATCH 07/16] libtrivfs: lock-less reference counting for
+ trivfs_peropen objects
+
+* libtrivfs/trivfs.h (struct trivfs_peropen): Use refcount_t for field
+refcnt.
+(struct trivfs_control): Remove unused field lock.
+* libtrivfs/cntl-create.c (trivfs_create_control): Drop the mutex
+initialization.
+* libtrivfs/io-reauthenticate.c (trivfs_S_io_reauthenticate): Adjust
+accordingly.
+* libtrivfs/io-restrict-auth.c (trivfs_S_io_restrict_auth): Likewise.
+* libtrivfs/open.c (trivfs_open): Initialize refcnt.
+* libtrivfs/protid-clean.c (trivfs_clean_protid): Likewise.
+* libtrivfs/protid-dup.c (trivfs_protid_dup): Likewise.
+---
+ libtrivfs/cntl-create.c       |  1 -
+ libtrivfs/io-reauthenticate.c |  5 +----
+ libtrivfs/io-restrict-auth.c  |  4 +---
+ libtrivfs/open.c              |  2 +-
+ libtrivfs/protid-clean.c      | 26 +++++++++++++++-----------
+ libtrivfs/protid-dup.c        |  5 +----
+ libtrivfs/trivfs.h            |  4 ++--
+ 7 files changed, 21 insertions(+), 26 deletions(-)
+
+diff --git a/libtrivfs/cntl-create.c b/libtrivfs/cntl-create.c
+index 910daf3..eb9a834 100644
+--- a/libtrivfs/cntl-create.c
++++ b/libtrivfs/cntl-create.c
+@@ -85,7 +85,6 @@ trivfs_create_control (mach_port_t underlying,
+ 	}
+ 
+       (*control)->hook = 0;
+-      pthread_mutex_init (&(*control)->lock, NULL);
+     }
+ 
+ out:
+diff --git a/libtrivfs/io-reauthenticate.c b/libtrivfs/io-reauthenticate.c
+index 7677697..df0ed2e 100644
+--- a/libtrivfs/io-reauthenticate.c
++++ b/libtrivfs/io-reauthenticate.c
+@@ -62,11 +62,8 @@ trivfs_S_io_reauthenticate (struct trivfs_protid *cred,
+     newcred->isroot = 1;
+ 
+   newcred->hook = cred->hook;
+-
+-  pthread_mutex_lock (&cred->po->cntl->lock);
+   newcred->po = cred->po;
+-  newcred->po->refcnt++;
+-  pthread_mutex_unlock (&cred->po->cntl->lock);
++  refcount_ref (&newcred->po->refcnt);
+ 
+   do
+     err = io_restrict_auth (newcred->po->cntl->underlying, &newcred->realnode,
+diff --git a/libtrivfs/io-restrict-auth.c b/libtrivfs/io-restrict-auth.c
+index 65b4fd6..39670fe 100644
+--- a/libtrivfs/io-restrict-auth.c
++++ b/libtrivfs/io-restrict-auth.c
+@@ -110,10 +110,8 @@ trivfs_S_io_restrict_auth (struct trivfs_protid *cred,
+     }
+ 
+   newcred->isroot = 0;
+-  pthread_mutex_lock (&cred->po->cntl->lock);
+   newcred->po = cred->po;
+-  newcred->po->refcnt++;
+-  pthread_mutex_unlock (&cred->po->cntl->lock);
++  refcount_ref (&newcred->po->refcnt);
+   if (cred->isroot && idvec_contains (user->uids, 0))
+     newcred->isroot = 1;
+   newcred->user = user;
+diff --git a/libtrivfs/open.c b/libtrivfs/open.c
+index f64d2ff..97e70a1 100644
+--- a/libtrivfs/open.c
++++ b/libtrivfs/open.c
+@@ -40,7 +40,7 @@ trivfs_open (struct trivfs_control *cntl,
+ 
+   ports_port_ref (cntl);
+ 
+-  po->refcnt = 1;
++  refcount_init (&po->refcnt, 1);
+   po->cntl = cntl;
+   po->openmodes = flags;
+   po->hook = 0;
+diff --git a/libtrivfs/protid-clean.c b/libtrivfs/protid-clean.c
+index f98da6a..cce736d 100644
+--- a/libtrivfs/protid-clean.c
++++ b/libtrivfs/protid-clean.c
+@@ -31,19 +31,23 @@ trivfs_clean_protid (void *arg)
+     (*trivfs_protid_destroy_hook) (cred);
+ 
+   /* If we hold the only reference to the peropen, try to get rid of it. */
+-  pthread_mutex_lock (&cntl->lock);
+-  if (cred->po->refcnt == 1 && trivfs_peropen_destroy_hook)
++  if (refcount_deref (&cred->po->refcnt) == 0)
+     {
+-      pthread_mutex_unlock (&cntl->lock);
+-      (*trivfs_peropen_destroy_hook) (cred->po);
+-      pthread_mutex_lock (&cntl->lock);
++      if (trivfs_peropen_destroy_hook)
++        {
++          /* Reaquire a reference while we call the hook.  */
++          refcount_ref (&cred->po->refcnt);
++          (*trivfs_peropen_destroy_hook) (cred->po);
++          if (refcount_deref (&cred->po->refcnt) == 0)
++            goto free_po;
++        }
++      else
++        {
++        free_po:
++          ports_port_deref (cntl);
++          free (cred->po);
++        }
+     }
+-  if (--cred->po->refcnt == 0)
+-    {
+-      ports_port_deref (cntl);
+-      free (cred->po);
+-    }
+-  pthread_mutex_unlock (&cntl->lock);
+ 
+   iohelp_free_iouser (cred->user);
+ 
+diff --git a/libtrivfs/protid-dup.c b/libtrivfs/protid-dup.c
+index 6169603..75f3ca8 100644
+--- a/libtrivfs/protid-dup.c
++++ b/libtrivfs/protid-dup.c
+@@ -35,11 +35,8 @@ trivfs_protid_dup (struct trivfs_protid *cred, struct trivfs_protid **dup)
+ 
+   if (! err)
+     {
+-      pthread_mutex_lock (&cred->po->cntl->lock);
+       new->po = cred->po;
+-      new->po->refcnt++;
+-      pthread_mutex_unlock (&cred->po->cntl->lock);
+-
++      refcount_ref (&new->po->refcnt);
+       new->isroot = cred->isroot;
+ 
+       err = iohelp_dup_iouser (&new->user, cred->user);
+diff --git a/libtrivfs/trivfs.h b/libtrivfs/trivfs.h
+index bb456ff..8902338 100644
+--- a/libtrivfs/trivfs.h
++++ b/libtrivfs/trivfs.h
+@@ -24,6 +24,7 @@
+ #include <mach/mach.h>
+ #include <hurd/ports.h>
+ #include <hurd/iohelp.h>
++#include <refcount.h>
+ 
+ struct trivfs_protid
+ {
+@@ -41,14 +42,13 @@ struct trivfs_peropen
+ {
+   void *hook;			/* for user use */
+   int openmodes;
+-  int refcnt;
++  refcount_t refcnt;
+   struct trivfs_control *cntl;
+ };
+ 
+ struct trivfs_control
+ {
+   struct port_info pi;
+-  pthread_mutex_t lock;
+   struct port_class *protid_class;
+   struct port_bucket *protid_bucket;
+   mach_port_t filesys_id;
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0008-libports-use-a-single-hash-table.patch b/debian/patches/0008-libports-use-a-single-hash-table.patch
new file mode 100644
index 00000000..bbfb0b8b
--- /dev/null
+++ b/debian/patches/0008-libports-use-a-single-hash-table.patch
@@ -0,0 +1,650 @@
+From 1a25b8c0ae213d06e722977ae0a0c470564038b3 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 3 May 2014 03:53:41 +0200
+Subject: [PATCH 08/16] libports: use a single hash table
+
+Previously, libports used a hash table per port bucket.  This makes
+looking up a port difficult if one does not know the port bucket, as
+one has to iterate over all buckets and do a hash table lookup each.
+
+Having to iterate over the buckets makes it necessary to keep a list
+of all buckets, which has to be updated and protected by a lock as
+well.
+
+Also, the current code in _ports_bucket_class_iterate iterates over
+the hash table associated with the bucket given.  When
+ports_class_iterate calls this common function, it obtains a reference
+to the bucket from one of the ports in the given class.  This will not
+work if a class contains ports in different port buckets.  This
+limitation is not documented as far as I can see.  Again, having to
+maintain this list has its cost and requires serialization.
+
+Use a single hash table instead.  Furthermore, serialize access to it
+using a separate lock.  Remove the linked lists of all buckets and all
+ports in a class.
+
+* libports/bucket-iterate.c (ports_bucket_iterate): Acquire
+_ports_htable_lock.  Also, generalize ports_bucket_iterate to treat
+the bucket argument the same way as the class argument.
+* libports/class-iterate.c (ports_class_iterate): Just call the
+generalized _ports_bucket_class_iterate with NULL as class.
+* libports/ports.h (struct port_info): Remove the port class links.
+(struct port_bucket): Remove the hash table, and the all buckets link.
+(_ports_all_buckets): Remove declaration.
+(_ports_htable): New global hash table.
+(_ports_htable_lock): Protected by this lock.
+* libports/claim-right.c: Adjust accordingly.
+* libports/complete-deallocate.c: Likewise.
+* libports/create-bucket.c: Likewise.
+* libports/create-class.c: Likewise.
+* libports/create-internal.c: Likewise.
+* libports/destroy-right.c: Likewise.
+* libports/import-port.c: Likewise.
+* libports/lookup-port.c: Likewise.
+* libports/reallocate-from-external.c: Likewise.
+* libports/reallocate-port.c: Likewise.
+* libports/transfer-right.c: Likewise.
+* libports/inhibit-all-rpcs.c: Iterate over the hash table.
+* libports/inhibit-bucket-rpcs.c: Likewise, but filter using bucket.
+* libports/inhibit-class-rpcs.c: Likewise, but filter using class.
+* libports/init.c (_ports_htable): Initialize.
+(_ports_htable_lock): Likewise.
+---
+ libports/bucket-iterate.c           | 22 +++++++++++++++-------
+ libports/claim-right.c              |  5 ++++-
+ libports/class-iterate.c            | 10 +---------
+ libports/complete-deallocate.c      |  7 +++----
+ libports/create-bucket.c            |  6 ------
+ libports/create-class.c             |  1 -
+ libports/create-internal.c          | 19 +++++++++++++------
+ libports/destroy-right.c            |  5 +++--
+ libports/import-port.c              | 19 +++++++++++++------
+ libports/inhibit-all-rpcs.c         | 27 +++++++++++++--------------
+ libports/inhibit-bucket-rpcs.c      |  3 ++-
+ libports/inhibit-class-rpcs.c       | 27 ++++++++++++++++++---------
+ libports/init.c                     |  7 ++++++-
+ libports/lookup-port.c              | 21 ++++++++-------------
+ libports/ports.h                    | 13 ++++++++-----
+ libports/reallocate-from-external.c | 15 +++++++++++----
+ libports/reallocate-port.c          |  9 ++++++++-
+ libports/transfer-right.c           | 18 ++++++++++++++----
+ 18 files changed, 140 insertions(+), 94 deletions(-)
+
+diff --git a/libports/bucket-iterate.c b/libports/bucket-iterate.c
+index babc204..06d8f7d 100644
+--- a/libports/bucket-iterate.c
++++ b/libports/bucket-iterate.c
+@@ -25,7 +25,7 @@
+ /* Internal entrypoint for both ports_bucket_iterate and ports_class_iterate.
+    If CLASS is non-null, call FUN only for ports in that class.  */
+ error_t
+-_ports_bucket_class_iterate (struct port_bucket *bucket,
++_ports_bucket_class_iterate (struct hurd_ihash *ht,
+ 			     struct port_class *class,
+ 			     error_t (*fun)(void *))
+ {
+@@ -36,23 +36,24 @@ _ports_bucket_class_iterate (struct port_bucket *bucket,
+   error_t err;
+ 
+   pthread_mutex_lock (&_ports_lock);
++  pthread_mutex_lock (&_ports_htable_lock);
+ 
+-  if (bucket->htable.nr_items == 0)
++  if (ht->nr_items == 0)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       return 0;
+     }
+ 
+-  nr_items = bucket->htable.nr_items;
++  nr_items = ht->nr_items;
+   p = malloc (nr_items * sizeof *p);
+   if (p == NULL)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       return ENOMEM;
+     }
+ 
+   n = 0;
+-  HURD_IHASH_ITERATE (&bucket->htable, arg)
++  HURD_IHASH_ITERATE (ht, arg)
+     {
+       struct port_info *const pi = arg;
+ 
+@@ -63,8 +64,15 @@ _ports_bucket_class_iterate (struct port_bucket *bucket,
+ 	  n++;
+ 	}
+     }
++  pthread_mutex_unlock (&_ports_htable_lock);
+   pthread_mutex_unlock (&_ports_lock);
+ 
++  if (n == 0)
++    {
++      free (p);
++      return 0;
++    }
++
+   if (n != nr_items)
+     {
+       /* We allocated too much.  Release unused memory.  */
+@@ -89,5 +97,5 @@ error_t
+ ports_bucket_iterate (struct port_bucket *bucket,
+ 		      error_t (*fun)(void *))
+ {
+-  return _ports_bucket_class_iterate (bucket, 0, fun);
++  return _ports_bucket_class_iterate (&bucket->htable, NULL, fun);
+ }
+diff --git a/libports/claim-right.c b/libports/claim-right.c
+index 4851ea3..11cc3ad 100644
+--- a/libports/claim-right.c
++++ b/libports/claim-right.c
+@@ -34,10 +34,13 @@ ports_claim_right (void *portstruct)
+   if (ret == MACH_PORT_NULL)
+     return ret;
+ 
+-  pthread_mutex_lock (&_ports_lock);
++  pthread_mutex_lock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+   hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++  pthread_mutex_unlock (&_ports_htable_lock);
+   err = mach_port_move_member (mach_task_self (), ret, MACH_PORT_NULL);
+   assert_perror (err);
++  pthread_mutex_lock (&_ports_lock);
+   pi->port_right = MACH_PORT_NULL;
+   if (pi->flags & PORT_HAS_SENDRIGHTS)
+     {
+diff --git a/libports/class-iterate.c b/libports/class-iterate.c
+index 1f8878a..df33818 100644
+--- a/libports/class-iterate.c
++++ b/libports/class-iterate.c
+@@ -23,13 +23,5 @@ error_t
+ ports_class_iterate (struct port_class *class,
+ 		     error_t (*fun)(void *))
+ {
+-  pthread_mutex_lock (&_ports_lock);
+-  if (class->ports != 0)
+-    {
+-      struct port_bucket *bucket = class->ports->bucket;
+-      pthread_mutex_unlock (&_ports_lock);
+-      return _ports_bucket_class_iterate (bucket, class, fun);
+-    }
+-  pthread_mutex_unlock (&_ports_lock);
+-  return 0;
++  return _ports_bucket_class_iterate (&_ports_htable, class, fun);
+ }
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 8ce095b..50548ec 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -29,16 +29,15 @@ _ports_complete_deallocate (struct port_info *pi)
+ 
+   if (pi->port_right)
+     {
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       mach_port_mod_refs (mach_task_self (), pi->port_right,
+ 			  MACH_PORT_RIGHT_RECEIVE, -1);
+       pi->port_right = MACH_PORT_NULL;
+     }
+ 
+-  *pi->prevp = pi->next;
+-  if (pi->next)
+-    pi->next->prevp = pi->prevp;
+-
+   pi->bucket->count--;
+   pi->class->count--;
+ 
+diff --git a/libports/create-bucket.c b/libports/create-bucket.c
+index 52d50c3..2c5f1b6 100644
+--- a/libports/create-bucket.c
++++ b/libports/create-bucket.c
+@@ -48,11 +48,5 @@ ports_create_bucket ()
+ 
+   hurd_ihash_init (&ret->htable, offsetof (struct port_info, hentry));
+   ret->rpcs = ret->flags = ret->count = 0;
+-
+-  pthread_mutex_lock (&_ports_lock);
+-  ret->next = _ports_all_buckets;
+-  _ports_all_buckets = ret;
+-  pthread_mutex_unlock (&_ports_lock);
+-
+   return ret;
+ }
+diff --git a/libports/create-class.c b/libports/create-class.c
+index 12c8add..782f52b 100644
+--- a/libports/create-class.c
++++ b/libports/create-class.c
+@@ -39,7 +39,6 @@ ports_create_class (void (*clean_routine)(void *),
+   cl->dropweak_routine = dropweak_routine;
+   cl->flags = 0;
+   cl->rpcs = 0;
+-  cl->ports = NULL;
+   cl->count = 0;
+   cl->uninhibitable_rpcs = ports_default_uninhibitable_rpcs;
+ 
+diff --git a/libports/create-internal.c b/libports/create-internal.c
+index 8551297..2981e74 100644
+--- a/libports/create-internal.c
++++ b/libports/create-internal.c
+@@ -81,15 +81,22 @@ _ports_create_port_internal (struct port_class *class,
+       goto loop;
+     }
+ 
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, port, pi);
++  if (err)
++    {
++      pthread_mutex_unlock (&_ports_htable_lock);
++      goto lose;
++    }
+   err = hurd_ihash_add (&bucket->htable, port, pi);
+   if (err)
+-    goto lose;
++    {
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
++      pthread_mutex_unlock (&_ports_htable_lock);
++      goto lose;
++    }
++  pthread_mutex_unlock (&_ports_htable_lock);
+ 
+-  pi->next = class->ports;
+-  pi->prevp = &class->ports;
+-  if (class->ports)
+-    class->ports->prevp = &pi->next;
+-  class->ports = pi;
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+diff --git a/libports/destroy-right.c b/libports/destroy-right.c
+index 65e19c7..aff7c02 100644
+--- a/libports/destroy-right.c
++++ b/libports/destroy-right.c
+@@ -30,12 +30,13 @@ ports_destroy_right (void *portstruct)
+ 
+   if (pi->port_right != MACH_PORT_NULL)
+     {
+-      pthread_mutex_lock (&_ports_lock);
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       err = mach_port_mod_refs (mach_task_self (), pi->port_right,
+ 				MACH_PORT_RIGHT_RECEIVE, -1);
+       assert_perror (err);
+-      pthread_mutex_unlock (&_ports_lock);
+ 
+       pi->port_right = MACH_PORT_NULL;
+ 
+diff --git a/libports/import-port.c b/libports/import-port.c
+index 226f47e..91afaa7 100644
+--- a/libports/import-port.c
++++ b/libports/import-port.c
+@@ -75,15 +75,22 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket,
+       goto loop;
+     }
+ 
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, port, pi);
++  if (err)
++    {
++      pthread_mutex_unlock (&_ports_htable_lock);
++      goto lose;
++    }
+   err = hurd_ihash_add (&bucket->htable, port, pi);
+   if (err)
+-    goto lose;
++    {
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
++      pthread_mutex_unlock (&_ports_htable_lock);
++      goto lose;
++    }
++  pthread_mutex_unlock (&_ports_htable_lock);
+ 
+-  pi->next = class->ports;
+-  pi->prevp = &class->ports;
+-  if (class->ports)
+-    class->ports->prevp = &pi->next;
+-  class->ports = pi;
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+diff --git a/libports/inhibit-all-rpcs.c b/libports/inhibit-all-rpcs.c
+index d4a54ba..83c291f 100644
+--- a/libports/inhibit-all-rpcs.c
++++ b/libports/inhibit-all-rpcs.c
+@@ -36,24 +36,23 @@ ports_inhibit_all_rpcs ()
+       struct port_bucket *bucket;
+       int this_one = 0;
+ 
+-      for (bucket = _ports_all_buckets; bucket; bucket = bucket->next)
++      pthread_mutex_lock (&_ports_htable_lock);
++      HURD_IHASH_ITERATE (&_ports_htable, portstruct)
+ 	{
+-	  HURD_IHASH_ITERATE (&bucket->htable, portstruct)
++	  struct rpc_info *rpc;
++	  struct port_info *pi = portstruct;
++
++	  for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
+ 	    {
+-	      struct rpc_info *rpc;
+-	      struct port_info *pi = portstruct;
+-	  
+-	      for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
+-		{
+-		  /* Avoid cancelling the calling thread if it's currently
+-		     handling a RPC.  */
+-		  if (rpc->thread == hurd_thread_self ())
+-		    this_one = 1;
+-		  else
+-		    hurd_thread_cancel (rpc->thread);
+-		}
++	      /* Avoid cancelling the calling thread if it's currently
++		 handling a RPC.  */
++	      if (rpc->thread == hurd_thread_self ())
++		this_one = 1;
++	      else
++		hurd_thread_cancel (rpc->thread);
+ 	    }
+ 	}
++      pthread_mutex_unlock (&_ports_htable_lock);
+ 
+       while (_ports_total_rpcs > this_one)
+ 	{
+diff --git a/libports/inhibit-bucket-rpcs.c b/libports/inhibit-bucket-rpcs.c
+index 965aa03..8c5a486 100644
+--- a/libports/inhibit-bucket-rpcs.c
++++ b/libports/inhibit-bucket-rpcs.c
+@@ -35,6 +35,7 @@ ports_inhibit_bucket_rpcs (struct port_bucket *bucket)
+     {
+       int this_one = 0;
+ 
++      pthread_mutex_lock (&_ports_htable_lock);
+       HURD_IHASH_ITERATE (&bucket->htable, portstruct)
+ 	{
+ 	  struct rpc_info *rpc;
+@@ -49,7 +50,7 @@ ports_inhibit_bucket_rpcs (struct port_bucket *bucket)
+ 		hurd_thread_cancel (rpc->thread);
+ 	    }
+ 	}
+-
++      pthread_mutex_unlock (&_ports_htable_lock);
+ 
+       while (bucket->rpcs > this_one)
+ 	{
+diff --git a/libports/inhibit-class-rpcs.c b/libports/inhibit-class-rpcs.c
+index 7ee8653..1580bdb 100644
+--- a/libports/inhibit-class-rpcs.c
++++ b/libports/inhibit-class-rpcs.c
+@@ -36,15 +36,24 @@ ports_inhibit_class_rpcs (struct port_class *class)
+       struct rpc_info *rpc;
+       int this_one = 0;
+ 
+-      for (pi = class->ports; pi; pi = pi->next)
+-	for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
+-	  {
+-	    /* Avoid cancelling the calling thread.  */
+-	    if (rpc->thread == hurd_thread_self ())
+-	      this_one = 1;
+-	    else
+-	      hurd_thread_cancel (rpc->thread);
+-	  }
++      pthread_mutex_lock (&_ports_htable_lock);
++      HURD_IHASH_ITERATE (&_ports_htable, portstruct)
++	{
++	  struct rpc_info *rpc;
++	  struct port_info *pi = portstruct;
++	  if (pi->class != class)
++	    continue;
++
++	  for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
++	    {
++	      /* Avoid cancelling the calling thread.  */
++	      if (rpc->thread == hurd_thread_self ())
++		this_one = 1;
++	      else
++		hurd_thread_cancel (rpc->thread);
++	    }
++	}
++      pthread_mutex_unlock (&_ports_htable_lock);
+ 
+       while (class->rpcs > this_one)
+ 	{
+diff --git a/libports/init.c b/libports/init.c
+index 3ef5388..d3aa90c 100644
+--- a/libports/init.c
++++ b/libports/init.c
+@@ -19,9 +19,14 @@
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 
+ #include "ports.h"
++#include <stddef.h>
+ 
+ pthread_mutex_t _ports_lock = PTHREAD_MUTEX_INITIALIZER;
+ pthread_cond_t _ports_block = PTHREAD_COND_INITIALIZER;
+-struct port_bucket *_ports_all_buckets;
++
++struct hurd_ihash _ports_htable =
++  HURD_IHASH_INITIALIZER (offsetof (struct port_info, ports_htable_entry));
++pthread_mutex_t _ports_htable_lock = PTHREAD_MUTEX_INITIALIZER;
++
+ int _ports_total_rpcs;
+ int _ports_flags;
+diff --git a/libports/lookup-port.c b/libports/lookup-port.c
+index f79f6f0..fbb13ef 100644
+--- a/libports/lookup-port.c
++++ b/libports/lookup-port.c
+@@ -26,26 +26,21 @@ ports_lookup_port (struct port_bucket *bucket,
+ 		   mach_port_t port,
+ 		   struct port_class *class)
+ {
+-  struct port_info *pi = 0;
+-  
++  struct port_info *pi;
++
+   pthread_mutex_lock (&_ports_lock);
++  pthread_mutex_lock (&_ports_htable_lock);
+ 
+-  if (bucket)
+-    pi = hurd_ihash_find (&bucket->htable, port);
+-  else
+-    for (bucket = _ports_all_buckets; bucket; bucket = bucket->next)
+-      {
+-	pi = hurd_ihash_find (&bucket->htable, port);
+-	if (pi)
+-	  break;
+-      }
+-  
+-  if (pi && class && pi->class != class)
++  pi = hurd_ihash_find (&_ports_htable, port);
++  if (pi
++      && ((class && pi->class != class)
++          || (bucket && pi->bucket != bucket)))
+     pi = 0;
+ 
+   if (pi)
+     pi->refcnt++;
+ 
++  pthread_mutex_unlock (&_ports_htable_lock);
+   pthread_mutex_unlock (&_ports_lock);
+   
+   return pi;
+diff --git a/libports/ports.h b/libports/ports.h
+index 7f13124..c29d78a 100644
+--- a/libports/ports.h
++++ b/libports/ports.h
+@@ -48,7 +48,7 @@ struct port_info
+   struct rpc_info *current_rpcs;
+   struct port_bucket *bucket;
+   hurd_ihash_locp_t hentry;
+-  struct port_info *next, **prevp; /* links on port_class list */
++  hurd_ihash_locp_t ports_htable_entry;
+ };
+ typedef struct port_info *port_info_t;
+ 
+@@ -65,7 +65,6 @@ struct port_bucket
+   int rpcs;
+   int flags;
+   int count;
+-  struct port_bucket *next;
+ };
+ /* FLAGS above are the following: */
+ #define PORT_BUCKET_INHIBITED	PORTS_INHIBITED
+@@ -78,7 +77,6 @@ struct port_class
+ {
+   int flags;
+   int rpcs;
+-  struct port_info *ports;
+   int count;
+   void (*clean_routine) (void *);
+   void (*dropweak_routine) (void *);
+@@ -277,7 +275,7 @@ error_t ports_class_iterate (struct port_class *class,
+ 			     error_t (*fun)(void *port));
+ 
+ /* Internal entrypoint for above two.  */
+-error_t _ports_bucket_class_iterate (struct port_bucket *bucket,
++error_t _ports_bucket_class_iterate (struct hurd_ihash *ht,
+ 				     struct port_class *class,
+ 				     error_t (*fun)(void *port));
+ 
+@@ -402,7 +400,12 @@ extern kern_return_t
+ /* Private data */
+ extern pthread_mutex_t _ports_lock;
+ extern pthread_cond_t _ports_block;
+-extern struct port_bucket *_ports_all_buckets;
++
++/* A hash table mapping port names to port_info objects.  */
++extern struct hurd_ihash _ports_htable;
++/* Access to the hash table is protected by this lock.  */
++extern pthread_mutex_t _ports_htable_lock;
++
+ extern int _ports_total_rpcs;
+ extern int _ports_flags;
+ #define _PORTS_INHIBITED	PORTS_INHIBITED
+diff --git a/libports/reallocate-from-external.c b/libports/reallocate-from-external.c
+index 8cccb2a..678b5d9 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -43,8 +43,11 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+ 			    MACH_PORT_RIGHT_RECEIVE, -1);
+   assert_perror (err);
+ 
++  pthread_mutex_lock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+   hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+-  
++  pthread_mutex_unlock (&_ports_htable_lock);
++
+   if ((pi->flags & PORT_HAS_SENDRIGHTS) && !stat.mps_srights)
+     {
+       dropref = 1;
+@@ -59,11 +62,15 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+   pi->port_right = receive;
+   pi->cancel_threshold = 0;
+   pi->mscount = stat.mps_mscount;
+-  
+-  err = hurd_ihash_add (&pi->bucket->htable, receive, pi);
++
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, receive, pi);
+   assert_perror (err);
++  err = hurd_ihash_add (&pi->bucket->htable, receive, pi);
++  pthread_mutex_unlock (&_ports_htable_lock);
+   pthread_mutex_unlock (&_ports_lock);
+-  
++  assert_perror (err);
++
+   mach_port_move_member (mach_task_self (), receive, pi->bucket->portset);
+   
+   if (stat.mps_srights)
+diff --git a/libports/reallocate-port.c b/libports/reallocate-port.c
+index d2adaeb..4a719e4 100644
+--- a/libports/reallocate-port.c
++++ b/libports/reallocate-port.c
+@@ -36,7 +36,10 @@ ports_reallocate_port (void *portstruct)
+ 			    MACH_PORT_RIGHT_RECEIVE, -1);
+   assert_perror (err);
+ 
++  pthread_mutex_lock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+   hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++  pthread_mutex_unlock (&_ports_htable_lock);
+ 
+   err = mach_port_allocate (mach_task_self (), MACH_PORT_RIGHT_RECEIVE,
+ 			    &pi->port_right);
+@@ -48,9 +51,13 @@ ports_reallocate_port (void *portstruct)
+     }
+   pi->cancel_threshold = 0;
+   pi->mscount = 0;
+-  err = hurd_ihash_add (&pi->bucket->htable, pi->port_right, pi);
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, pi->port_right, pi);
+   assert_perror (err);
++  err = hurd_ihash_add (&pi->bucket->htable, pi->port_right, pi);
++  pthread_mutex_unlock (&_ports_htable_lock);
+   pthread_mutex_unlock (&_ports_lock);
++  assert_perror (err);
+ 
+   err = mach_port_move_member (mach_task_self (), pi->port_right, 
+ 			       pi->bucket->portset);
+diff --git a/libports/transfer-right.c b/libports/transfer-right.c
+index 72488a9..3f23d93 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -41,7 +41,10 @@ ports_transfer_right (void *tostruct,
+   port = frompi->port_right;
+   if (port != MACH_PORT_NULL)
+     {
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, frompi->ports_htable_entry);
+       hurd_ihash_locp_remove (&frompi->bucket->htable, frompi->hentry);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       frompi->port_right = MACH_PORT_NULL;
+       if (frompi->flags & PORT_HAS_SENDRIGHTS)
+ 	{
+@@ -54,7 +57,10 @@ ports_transfer_right (void *tostruct,
+   /* Destroy the existing right in TOPI. */
+   if (topi->port_right != MACH_PORT_NULL)
+     {
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, topi->ports_htable_entry);
+       hurd_ihash_locp_remove (&topi->bucket->htable, topi->hentry);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       err = mach_port_mod_refs (mach_task_self (), topi->port_right,
+ 				MACH_PORT_RIGHT_RECEIVE, -1);
+       assert_perror (err);
+@@ -74,10 +80,16 @@ ports_transfer_right (void *tostruct,
+   topi->port_right = port;
+   topi->cancel_threshold = frompi->cancel_threshold;
+   topi->mscount = frompi->mscount;
+-  
++
++  pthread_mutex_unlock (&_ports_lock);
++
+   if (port)
+     {
++      pthread_mutex_lock (&_ports_htable_lock);
++      err = hurd_ihash_add (&_ports_htable, port, topi);
++      assert_perror (err);
+       err = hurd_ihash_add (&topi->bucket->htable, port, topi);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       assert_perror (err);
+       if (topi->bucket != frompi->bucket)
+         {
+@@ -86,9 +98,7 @@ ports_transfer_right (void *tostruct,
+ 	  assert_perror (err);
+ 	}
+     }
+-  
+-  pthread_mutex_unlock (&_ports_lock);
+-  
++
+   /* Take care of any lowered reference counts. */
+   if (dereffrompi)
+     ports_port_deref (frompi);
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0009-libports-lock-less-reference-counting-for-port_info-.patch b/debian/patches/0009-libports-lock-less-reference-counting-for-port_info-.patch
new file mode 100644
index 00000000..1a2aa202
--- /dev/null
+++ b/debian/patches/0009-libports-lock-less-reference-counting-for-port_info-.patch
@@ -0,0 +1,345 @@
+From c91ba928692076487f328a709928ff718a9364ac Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 3 May 2014 01:02:35 +0200
+Subject: [PATCH 09/16] libports: lock-less reference counting for port_info
+ objects
+
+* libports/ports.h (struct port_info): Use the new type.
+* libports/lookup-port.c: No need to lock _ports_lock anymore.
+* libports/bucket-iterate.c: Likewise.
+* libports/complete-deallocate.c: Check if someone reacquired a
+reference through a hash table lookup.
+* libports/create-internal.c: Use the new reference counting primitives.
+* libports/get-right.c: Likewise.
+* libports/import-port.c: Likewise.
+* libports/port-deref-weak.c: Likewise.
+* libports/port-deref.c: Likewise.
+* libports/port-ref-weak.c: Likewise.
+* libports/port-ref.c: Likewise.
+* libports/reallocate-from-external.c: Likewise.
+* libports/transfer-right.c: Likewise.
+* utils/rpctrace.c: Likewise.
+---
+ libports/bucket-iterate.c           |  4 +---
+ libports/complete-deallocate.c      | 14 ++++++++++++++
+ libports/create-internal.c          |  3 +--
+ libports/get-right.c                |  2 +-
+ libports/import-port.c              |  3 +--
+ libports/lookup-port.c              |  6 ++----
+ libports/port-deref-weak.c          | 10 +++-------
+ libports/port-deref.c               | 34 ++++++++++++++++------------------
+ libports/port-ref-weak.c            |  8 +++-----
+ libports/port-ref.c                 |  8 +++-----
+ libports/ports.h                    |  4 ++--
+ libports/reallocate-from-external.c |  2 +-
+ libports/transfer-right.c           |  2 +-
+ utils/rpctrace.c                    | 10 ++++++++--
+ 14 files changed, 57 insertions(+), 53 deletions(-)
+
+diff --git a/libports/bucket-iterate.c b/libports/bucket-iterate.c
+index 06d8f7d..8a28827 100644
+--- a/libports/bucket-iterate.c
++++ b/libports/bucket-iterate.c
+@@ -35,7 +35,6 @@ _ports_bucket_class_iterate (struct hurd_ihash *ht,
+   size_t i, n, nr_items;
+   error_t err;
+ 
+-  pthread_mutex_lock (&_ports_lock);
+   pthread_mutex_lock (&_ports_htable_lock);
+ 
+   if (ht->nr_items == 0)
+@@ -59,13 +58,12 @@ _ports_bucket_class_iterate (struct hurd_ihash *ht,
+ 
+       if (class == 0 || pi->class == class)
+ 	{
+-	  pi->refcnt++;
++	  refcounts_ref (&pi->refcounts, NULL);
+ 	  p[n] = pi;
+ 	  n++;
+ 	}
+     }
+   pthread_mutex_unlock (&_ports_htable_lock);
+-  pthread_mutex_unlock (&_ports_lock);
+ 
+   if (n == 0)
+     {
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 50548ec..a239957 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -29,15 +29,29 @@ _ports_complete_deallocate (struct port_info *pi)
+ 
+   if (pi->port_right)
+     {
++      struct references result;
++
+       pthread_mutex_lock (&_ports_htable_lock);
++      refcounts_references (&pi->refcounts, &result);
++      if (result.hard > 0 || result.weak > 0)
++        {
++          /* A reference was reacquired through a hash table lookup.
++             It's fine, we didn't touch anything yet. */
++          pthread_mutex_unlock (&_ports_htable_lock);
++          return;
++        }
++
+       hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+       pthread_mutex_unlock (&_ports_htable_lock);
++
+       mach_port_mod_refs (mach_task_self (), pi->port_right,
+ 			  MACH_PORT_RIGHT_RECEIVE, -1);
+       pi->port_right = MACH_PORT_NULL;
+     }
+ 
++  pthread_mutex_lock (&_ports_lock);
++
+   pi->bucket->count--;
+   pi->class->count--;
+ 
+diff --git a/libports/create-internal.c b/libports/create-internal.c
+index 2981e74..4f1e512 100644
+--- a/libports/create-internal.c
++++ b/libports/create-internal.c
+@@ -54,8 +54,7 @@ _ports_create_port_internal (struct port_class *class,
+     }
+ 
+   pi->class = class;
+-  pi->refcnt = 1;
+-  pi->weakrefcnt = 0;
++  refcounts_init (&pi->refcounts, 1, 0);
+   pi->cancel_threshold = 0;
+   pi->mscount = 0;
+   pi->flags = 0;
+diff --git a/libports/get-right.c b/libports/get-right.c
+index 89050c6..8681f46 100644
+--- a/libports/get-right.c
++++ b/libports/get-right.c
+@@ -41,7 +41,7 @@ ports_get_right (void *port)
+   if ((pi->flags & PORT_HAS_SENDRIGHTS) == 0)
+     {
+       pi->flags |= PORT_HAS_SENDRIGHTS;
+-      pi->refcnt++;
++      refcounts_ref (&pi->refcounts, NULL);
+       err = mach_port_request_notification (mach_task_self (),
+ 					    pi->port_right,
+ 					    MACH_NOTIFY_NO_SENDERS,
+diff --git a/libports/import-port.c b/libports/import-port.c
+index 91afaa7..8601d0e 100644
+--- a/libports/import-port.c
++++ b/libports/import-port.c
+@@ -48,8 +48,7 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket,
+     return ENOMEM;
+   
+   pi->class = class;
+-  pi->refcnt = 1 + !!stat.mps_srights;
+-  pi->weakrefcnt = 0;
++  refcounts_init (&pi->refcounts, 1 + !!stat.mps_srights, 0);
+   pi->cancel_threshold = 0;
+   pi->mscount = stat.mps_mscount;
+   pi->flags = stat.mps_srights ? PORT_HAS_SENDRIGHTS : 0;
+diff --git a/libports/lookup-port.c b/libports/lookup-port.c
+index fbb13ef..1bf012f 100644
+--- a/libports/lookup-port.c
++++ b/libports/lookup-port.c
+@@ -28,7 +28,6 @@ ports_lookup_port (struct port_bucket *bucket,
+ {
+   struct port_info *pi;
+ 
+-  pthread_mutex_lock (&_ports_lock);
+   pthread_mutex_lock (&_ports_htable_lock);
+ 
+   pi = hurd_ihash_find (&_ports_htable, port);
+@@ -38,10 +37,9 @@ ports_lookup_port (struct port_bucket *bucket,
+     pi = 0;
+ 
+   if (pi)
+-    pi->refcnt++;
++    ports_port_ref (pi);
+ 
+   pthread_mutex_unlock (&_ports_htable_lock);
+-  pthread_mutex_unlock (&_ports_lock);
+-  
++
+   return pi;
+ }
+diff --git a/libports/port-deref-weak.c b/libports/port-deref-weak.c
+index beb4842..8432660 100644
+--- a/libports/port-deref-weak.c
++++ b/libports/port-deref-weak.c
+@@ -25,12 +25,8 @@ void
+ ports_port_deref_weak (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  assert (pi->weakrefcnt);
+-  pi->weakrefcnt--;
+-  if (pi->refcnt == 0 && pi->weakrefcnt == 0)
++  struct references result;
++  refcounts_deref_weak (&pi->refcounts, &result);
++  if (result.hard == 0 && result.weak == 0)
+     _ports_complete_deallocate (pi);
+-  else
+-    pthread_mutex_unlock (&_ports_lock);
+ }
+diff --git a/libports/port-deref.c b/libports/port-deref.c
+index cf9b238..b97dd13 100644
+--- a/libports/port-deref.c
++++ b/libports/port-deref.c
+@@ -25,26 +25,24 @@ void
+ ports_port_deref (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  int trieddroppingweakrefs = 0;
+-
+- retry:
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  
+-  if (pi->refcnt == 1 && pi->weakrefcnt
+-      && pi->class->dropweak_routine && !trieddroppingweakrefs)
++  struct references result;
++
++  if (pi->class->dropweak_routine)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
+-      (*pi->class->dropweak_routine) (pi);
+-      trieddroppingweakrefs = 1;
+-      goto retry;
++      /* If we need to call the dropweak routine, we need to hold one
++         reference while doing so.  We use a weak reference for this
++         purpose, which we acquire by demoting our hard reference to a
++         weak one.  */
++      refcounts_demote (&pi->refcounts, &result);
++
++      if (result.hard == 0 && result.weak > 1)
++        (*pi->class->dropweak_routine) (pi);
++
++      refcounts_deref_weak (&pi->refcounts, &result);
+     }
+-  
+-  assert (pi->refcnt);
++  else
++    refcounts_deref (&pi->refcounts, &result);
+ 
+-  pi->refcnt--;
+-  if (pi->refcnt == 0 && pi->weakrefcnt == 0)
++  if (result.hard == 0 && result.weak == 0)
+     _ports_complete_deallocate (pi);
+-  else
+-    pthread_mutex_unlock (&_ports_lock);
+ }
+diff --git a/libports/port-ref-weak.c b/libports/port-ref-weak.c
+index c7d3c69..e4b7fc8 100644
+--- a/libports/port-ref-weak.c
++++ b/libports/port-ref-weak.c
+@@ -25,9 +25,7 @@ void
+ ports_port_ref_weak (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  assert (pi->refcnt || pi->weakrefcnt);
+-  pi->weakrefcnt++;
+-  pthread_mutex_unlock (&_ports_lock);
++  struct references result;
++  refcounts_ref_weak (&pi->refcounts, &result);
++  assert (result.hard > 0 || result.weak > 1);
+ }
+diff --git a/libports/port-ref.c b/libports/port-ref.c
+index 92b7118..761c50f 100644
+--- a/libports/port-ref.c
++++ b/libports/port-ref.c
+@@ -25,9 +25,7 @@ void
+ ports_port_ref (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  assert (pi->refcnt || pi->weakrefcnt);
+-  pi->refcnt++;
+-  pthread_mutex_unlock (&_ports_lock);
++  struct references result;
++  refcounts_ref (&pi->refcounts, &result);
++  assert (result.hard > 1 || result.weak > 0);
+ }
+diff --git a/libports/ports.h b/libports/ports.h
+index c29d78a..3439443 100644
+--- a/libports/ports.h
++++ b/libports/ports.h
+@@ -27,6 +27,7 @@
+ #include <hurd/ihash.h>
+ #include <mach/notify.h>
+ #include <pthread.h>
++#include <refcount.h>
+ 
+ /* These are global values for common flags used in the various structures.
+    Not all of these are meaningful in all flag fields.  */
+@@ -39,8 +40,7 @@
+ struct port_info
+ {
+   struct port_class *class;
+-  int refcnt;
+-  int weakrefcnt;
++  refcounts_t refcounts;
+   mach_port_mscount_t mscount;
+   mach_msg_seqno_t cancel_threshold;
+   int flags;
+diff --git a/libports/reallocate-from-external.c b/libports/reallocate-from-external.c
+index 678b5d9..a912725 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -56,7 +56,7 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+   else if (((pi->flags & PORT_HAS_SENDRIGHTS) == 0) && stat.mps_srights)
+     {
+       pi->flags |= PORT_HAS_SENDRIGHTS;
+-      pi->refcnt++;
++      refcounts_ref (&pi->refcounts, NULL);
+     }
+   
+   pi->port_right = receive;
+diff --git a/libports/transfer-right.c b/libports/transfer-right.c
+index 3f23d93..0e898ba 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -72,7 +72,7 @@ ports_transfer_right (void *tostruct,
+       else if (((topi->flags & PORT_HAS_SENDRIGHTS) == 0) && hassendrights)
+ 	{
+ 	  topi->flags |= PORT_HAS_SENDRIGHTS;
+-	  topi->refcnt++;
++	  refcounts_ref (&topi->refcounts, NULL);
+ 	}
+     }
+   
+diff --git a/utils/rpctrace.c b/utils/rpctrace.c
+index fc913e3..b11fea4 100644
+--- a/utils/rpctrace.c
++++ b/utils/rpctrace.c
+@@ -431,7 +431,9 @@ destroy_receiver_info (struct receiver_info *info)
+   while (send_wrapper)
+     {
+       struct sender_info *next = send_wrapper->next;
+-      assert (TRACED_INFO (send_wrapper)->pi.refcnt == 1);
++      assert (
++	refcounts_hard_references (&TRACED_INFO (send_wrapper)->pi.refcounts)
++	== 1);
+       /* Reset the receive_right of the send wrapper in advance to avoid
+        * destroy_receiver_info is called when the port info is destroyed. */
+       send_wrapper->receive_right = NULL;
+@@ -848,7 +850,11 @@ rewrite_right (mach_port_t *right, mach_msg_type_name_t *type,
+ 	    hurd_ihash_locp_remove (&traced_names, receiver_info->locp);
+ 
+ 	    send_wrapper2 = get_send_wrapper (receiver_info, dest, &rr);
+-	    assert (TRACED_INFO (send_wrapper2)->pi.refcnt == 1);
++	    assert (
++	      refcounts_hard_references (
++		&TRACED_INFO (send_wrapper2)->pi.refcounts)
++	      == 1);
++
+ 	    name = TRACED_INFO (send_wrapper2)->name;
+ 	    TRACED_INFO (send_wrapper2)->name = NULL;
+ 	    /* send_wrapper2 isn't destroyed normally, so we need to unlink
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0010-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0010-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
new file mode 100644
index 00000000..0a8adb3f
--- /dev/null
+++ b/debian/patches/0010-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
@@ -0,0 +1,190 @@
+From 57ec68e1f87ffc1d76a9119c04031f919883065f Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 13 May 2014 13:09:15 +0200
+Subject: [PATCH 10/16] ext2fs: use a seperate lock to protect nodehash
+
+Previously, ext2fs used diskfs_node_refcnt_lock to serialize access to
+the nodehash.
+
+Use a separate lock to protect nodehash.  Adjust the reference
+counting accordingly.  Every node in the nodehash carries a light
+reference.  When we are asked to give up that light reference, we
+reacquire our lock momentarily to check whether someone else
+reacquired a reference through the nodehash.
+
+* ext2fs/inode.c (nodehash_lock): New lock.
+(diskfs_cached_lookup): Use a separate lock to protect nodehash.
+Adjust the reference counting accordingly.
+(ifind): Likewise.
+(diskfs_node_iterate): Likewise.
+(diskfs_node_norefs): Move the code removing the node from nodehash...
+(diskfs_try_dropping_softrefs): ... here, where we check whether
+someone reacquired a reference, and if so hold on to our light
+reference.
+---
+ ext2fs/inode.c | 68 ++++++++++++++++++++++++++++++++++++++++++----------------
+ 1 file changed, 50 insertions(+), 18 deletions(-)
+
+diff --git a/ext2fs/inode.c b/ext2fs/inode.c
+index ed78265..aa070a2 100644
+--- a/ext2fs/inode.c
++++ b/ext2fs/inode.c
+@@ -46,8 +46,18 @@
+ #define	INOHASH(ino)	(((unsigned)(ino))%INOHSZ)
+ #endif
+ 
++/* The nodehash is a cache of nodes.
++
++   Access to nodehash and nodehash_nr_items is protected by
++   nodehash_lock.
++
++   Every node in the nodehash carries a light reference.  When we are
++   asked to give up that light reference, we reacquire our lock
++   momentarily to check whether someone else reacquired a reference
++   through the nodehash.  */
+ static struct node *nodehash[INOHSZ];
+ static size_t nodehash_nr_items;
++static pthread_mutex_t nodehash_lock = PTHREAD_MUTEX_INITIALIZER;
+ 
+ static error_t read_node (struct node *np);
+ 
+@@ -71,12 +81,12 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+   struct node *np;
+   struct disknode *dn;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+   for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+     if (np->cache_id == inum)
+       {
+-	np->references++;
+-	pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	diskfs_nref (np);
++	pthread_mutex_unlock (&nodehash_lock);
+ 	pthread_mutex_lock (&np->lock);
+ 	*npp = np;
+ 	return 0;
+@@ -86,7 +96,7 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+   dn = malloc (sizeof (struct disknode));
+   if (! dn)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&nodehash_lock);
+       return ENOMEM;
+     }
+   dn->dirents = 0;
+@@ -107,9 +117,10 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  diskfs_nref_light (np);
+   nodehash_nr_items += 1;
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&nodehash_lock);
+ 
+   /* Get the contents of NP off disk.  */
+   err = read_node (np);
+@@ -140,14 +151,13 @@ ifind (ino_t inum)
+ {
+   struct node *np;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+   for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+     {
+       if (np->cache_id != inum)
+ 	continue;
+ 
+-      assert (np->references);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&nodehash_lock);
+       return np;
+     }
+   assert (0);
+@@ -158,11 +168,6 @@ ifind (ino_t inum)
+ void
+ diskfs_node_norefs (struct node *np)
+ {
+-  *np->dn->hprevp = np->dn->hnext;
+-  if (np->dn->hnext)
+-    np->dn->hnext->dn->hprevp = np->dn->hprevp;
+-  nodehash_nr_items -= 1;
+-
+   if (np->dn->dirents)
+     free (np->dn->dirents);
+   assert (!np->dn->pager);
+@@ -180,6 +185,33 @@ diskfs_node_norefs (struct node *np)
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_mutex_lock (&nodehash_lock);
++  if (np->dn->hnext != NULL)
++    {
++      /* Check if someone reacquired a reference through the
++         nodehash.  */
++      unsigned int references;
++      pthread_spin_lock (&diskfs_node_refcnt_lock);
++      references = np->references;
++      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++      if (references > 0)
++        {
++          /* A reference was reacquired through a hash table lookup.
++             It's fine, we didn't touch anything yet. */
++          pthread_mutex_unlock (&nodehash_lock);
++          return;
++        }
++
++      *np->dn->hprevp = np->dn->hnext;
++      if (np->dn->hnext)
++        np->dn->hnext->dn->hprevp = np->dn->hprevp;
++      np->dn->hnext = NULL;
++      nodehash_nr_items -= 1;
++      diskfs_nrele_light (np);
++    }
++  pthread_mutex_unlock (&nodehash_lock);
++
+   drop_pager_softrefs (np);
+ }
+ 
+@@ -556,12 +588,12 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+   size_t num_nodes;
+   struct node *node, **node_list, **p;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+ 
+   /* We must copy everything from the hash table into another data structure
+      to avoid running into any problems with the hash-table being modified
+      during processing (normally we delegate access to hash-table with
+-     diskfs_node_refcnt_lock, but we can't hold this while locking the
++     nodehash_lock, but we can't hold this while locking the
+      individual node locks).  */
+   num_nodes = nodehash_nr_items;
+ 
+@@ -570,7 +602,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+   node_list = malloc (num_nodes * sizeof (struct node *));
+   if (node_list == NULL)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&nodehash_lock);
+       ext2_debug ("unable to allocate temporary node table");
+       return ENOMEM;
+     }
+@@ -580,10 +612,10 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+     for (node = nodehash[n]; node; node = node->dn->hnext)
+       {
+ 	*p++ = node;
+-	node->references++;
++	diskfs_nref (node);
+       }
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&nodehash_lock);
+ 
+   p = node_list;
+   while (num_nodes-- > 0)
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0011-fatfs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0011-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
new file mode 100644
index 00000000..d9e6800c
--- /dev/null
+++ b/debian/patches/0011-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
@@ -0,0 +1,222 @@
+From 1d458c0ca0e9caceef2828bdfbf7cbe4495b9f3e Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 13 May 2014 15:14:53 +0200
+Subject: [PATCH 11/16] fatfs: use a seperate lock to protect nodehash
+
+Previously, fatfs used diskfs_node_refcnt_lock to serialize access to
+the nodehash.
+
+Use a separate lock to protect nodehash.  Adjust the reference
+counting accordingly.  Every node in the nodehash carries a light
+reference.  When we are asked to give up that light reference, we
+reacquire our lock momentarily to check whether someone else
+reacquired a reference through the nodehash.
+
+* fatfs/inode.c (nodehash_lock): New lock.
+(diskfs_cached_lookup): Use a separate lock to protect nodehash.
+Adjust the reference counting accordingly.
+(ifind): Likewise.
+(diskfs_node_iterate): Likewise.
+(diskfs_node_norefs): Move the code removing the node from nodehash...
+(diskfs_try_dropping_softrefs): ... here, where we check whether
+someone reacquired a reference, and if so hold on to our light
+reference.
+---
+ fatfs/inode.c | 81 +++++++++++++++++++++++++++++++++++++++++------------------
+ 1 file changed, 57 insertions(+), 24 deletions(-)
+
+diff --git a/fatfs/inode.c b/fatfs/inode.c
+index ed6f3f0..8b3385b 100644
+--- a/fatfs/inode.c
++++ b/fatfs/inode.c
+@@ -44,8 +44,18 @@
+ #define INOHASH(ino)    (((unsigned)(ino))%INOHSZ)
+ #endif
+ 
++/* The nodehash is a cache of nodes.
++
++   Access to nodehash and nodehash_nr_items is protected by
++   nodehash_lock.
++
++   Every node in the nodehash carries a light reference.  When we are
++   asked to give up that light reference, we reacquire our lock
++   momentarily to check whether someone else reacquired a reference
++   through the nodehash.  */
+ static struct node *nodehash[INOHSZ];
+ static size_t nodehash_nr_items;
++static pthread_mutex_t nodehash_lock = PTHREAD_MUTEX_INITIALIZER;
+ 
+ static error_t read_node (struct node *np, vm_address_t buf);
+ 
+@@ -67,12 +77,12 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
+   struct node *np;
+   struct disknode *dn;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+   for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+     if (np->cache_id == inum)
+       {
+-        np->references++;
+-        pthread_spin_unlock (&diskfs_node_refcnt_lock);
++        diskfs_nref (np);
++        pthread_mutex_unlock (&nodehash_lock);
+         pthread_mutex_lock (&np->lock);
+         *npp = np;
+         return 0;
+@@ -82,7 +92,7 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
+   dn = malloc (sizeof (struct disknode));
+   if (! dn)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&nodehash_lock);
+       return ENOMEM;
+     }
+   dn->pager = 0;
+@@ -107,10 +117,11 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  diskfs_nref_light (np);
+   nodehash_nr_items += 1;
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-  
++  pthread_mutex_unlock (&nodehash_lock);
++
+   /* Get the contents of NP off disk.  */
+   err = read_node (np, 0);
+ 
+@@ -133,12 +144,12 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
+   struct node *np;
+   struct disknode *dn;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+   for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+     if (np->cache_id == inum)
+       {
+-        np->references++;
+-        pthread_spin_unlock (&diskfs_node_refcnt_lock);
++        diskfs_nref (np);
++        pthread_mutex_unlock (&nodehash_lock);
+         pthread_mutex_lock (&np->lock);
+         *npp = np;
+         return 0;
+@@ -148,7 +159,7 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
+   dn = malloc (sizeof (struct disknode));
+   if (! dn)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&nodehash_lock);
+       return ENOMEM;
+     }
+   dn->pager = 0;
+@@ -173,10 +184,11 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  diskfs_nref_light (np);
+   nodehash_nr_items += 1;
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-  
++  pthread_mutex_unlock (&nodehash_lock);
++
+   /* Get the contents of NP off disk.  */
+   err = read_node (np, buf);
+ 
+@@ -196,14 +208,13 @@ ifind (ino_t inum)
+ {
+   struct node *np;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+   for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+     {
+       if (np->cache_id != inum)
+         continue;
+ 
+-      assert (np->references);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&nodehash_lock);
+       return np;
+     }
+   assert (0);
+@@ -216,11 +227,6 @@ diskfs_node_norefs (struct node *np)
+ {
+   struct cluster_chain *last = np->dn->first;
+ 
+-  *np->dn->hprevp = np->dn->hnext;
+-  if (np->dn->hnext)
+-    np->dn->hnext->dn->hprevp = np->dn->hprevp;
+-  nodehash_nr_items -= 1;
+-
+   while (last)
+     {
+       struct cluster_chain *next = last->next;
+@@ -251,6 +257,33 @@ diskfs_node_norefs (struct node *np)
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_mutex_lock (&nodehash_lock);
++  if (np->dn->hnext != NULL)
++    {
++      /* Check if someone reacquired a reference through the
++         nodehash.  */
++      unsigned int references;
++      pthread_spin_lock (&diskfs_node_refcnt_lock);
++      references = np->references;
++      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++      if (references > 0)
++        {
++          /* A reference was reacquired through a hash table lookup.
++             It's fine, we didn't touch anything yet. */
++          pthread_mutex_unlock (&nodehash_lock);
++          return;
++        }
++
++      *np->dn->hprevp = np->dn->hnext;
++      if (np->dn->hnext)
++        np->dn->hnext->dn->hprevp = np->dn->hprevp;
++      np->dn->hnext = NULL;
++      nodehash_nr_items -= 1;
++      diskfs_nrele_light (np);
++    }
++  pthread_mutex_unlock (&nodehash_lock);
++
+   drop_pager_softrefs (np);
+ }
+ 
+@@ -554,12 +587,12 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+   size_t num_nodes;
+   struct node *node, **node_list, **p;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&nodehash_lock);
+ 
+   /* We must copy everything from the hash table into another data structure
+      to avoid running into any problems with the hash-table being modified
+      during processing (normally we delegate access to hash-table with
+-     diskfs_node_refcnt_lock, but we can't hold this while locking the
++     nodehash_lock, but we can't hold this while locking the
+      individual node locks).  */
+ 
+   num_nodes = nodehash_nr_items;
+@@ -570,10 +603,10 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+     for (node = nodehash[n]; node; node = node->dn->hnext)
+       {
+         *p++ = node;
+-        node->references++;
++        diskfs_nref (node);
+       }
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&nodehash_lock);
+ 
+   p = node_list;
+   while (num_nodes-- > 0)
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0012-isofs-use-a-seperate-lock-to-protect-node_cache.patch b/debian/patches/0012-isofs-use-a-seperate-lock-to-protect-node_cache.patch
new file mode 100644
index 00000000..de1816da
--- /dev/null
+++ b/debian/patches/0012-isofs-use-a-seperate-lock-to-protect-node_cache.patch
@@ -0,0 +1,222 @@
+From a978a9c1692644b033d4b3baaf69d30d0a475364 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 13 May 2014 15:16:31 +0200
+Subject: [PATCH 12/16] isofs: use a seperate lock to protect node_cache
+
+Previously, isofs used diskfs_node_refcnt_lock to serialize access to
+the node_cache.
+
+Use a separate lock to protect node_cache.  Adjust the reference
+counting accordingly.  Every node in the node_cache carries a light
+reference.  When we are asked to give up that light reference, we
+reacquire our lock momentarily to check whether someone else
+reacquired a reference through the node_cache.
+
+* isofs/inode.c (node_cache_lock): New lock.
+(inode_cache_find): Use a separate lock to protect node_cache.
+Adjust the reference counting accordingly.
+(diskfs_cached_lookup): Likewise.
+(load_inode): Likewise.
+(cache_inode): Update comment accordingly.
+(diskfs_node_iterate): Likewise.
+(diskfs_node_norefs): Move the code removing the node from node_cache...
+(diskfs_try_dropping_softrefs): ... here, where we check whether
+someone reacquired a reference, and if so hold on to our light
+reference.
+---
+ isofs/inode.c | 72 +++++++++++++++++++++++++++++++++++++++++++----------------
+ 1 file changed, 53 insertions(+), 19 deletions(-)
+
+diff --git a/isofs/inode.c b/isofs/inode.c
+index cdc05ae..4f22086 100644
+--- a/isofs/inode.c
++++ b/isofs/inode.c
+@@ -48,9 +48,19 @@ struct node_cache
+   struct node *np;		/* if live */
+ };
+ 
++/* The node_cache is a cache of nodes.
++
++   Access to node_cache, node_cache_size, and node_cache_alloced is
++   protected by node_cache_lock.
++
++   Every node in the node_cache carries a light reference.  When we
++   are asked to give up that light reference, we reacquire our lock
++   momentarily to check whether someone else reacquired a reference
++   through the node_cache.  */
+ static int node_cache_size = 0;
+ static int node_cache_alloced = 0;
+ struct node_cache *node_cache = 0;
++static pthread_mutex_t node_cache_lock = PTHREAD_MUTEX_INITIALIZER;
+ 
+ /* Forward */
+ static error_t read_disknode (struct node *,
+@@ -58,7 +68,7 @@ static error_t read_disknode (struct node *,
+ 
+ 
+ /* See if node with identifier ID is in the cache.  If so, return it,
+-   with one additional reference. diskfs_node_refcnt_lock must be held
++   with one additional reference. node_cache_lock must be held
+    on entry to the call, and will be released iff the node was found
+    in the cache. */
+ void
+@@ -71,8 +81,8 @@ inode_cache_find (off_t id, struct node **npp)
+ 	&& node_cache[i].np)
+       {
+ 	*npp = node_cache[i].np;
+-	(*npp)->references++;
+-	pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	diskfs_nref (*npp);
++	pthread_mutex_unlock (&node_cache_lock);
+ 	pthread_mutex_lock (&(*npp)->lock);
+ 	return;
+       }
+@@ -92,7 +102,7 @@ use_file_start_id (struct dirrect *record, struct rrip_lookup *rr)
+ }
+ 
+ /* Enter NP into the cache.  The directory entry we used is DR, the
+-   cached Rock-Ridge info RR. diskfs_node_refcnt_lock must be held. */
++   cached Rock-Ridge info RR. node_cache_lock must be held. */
+ void
+ cache_inode (struct node *np, struct dirrect *record,
+ 	    struct rrip_lookup *rr)
+@@ -155,7 +165,7 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+      to avoid presenting zero cache ID's. */
+   id--;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&node_cache_lock);
+   assert (id < node_cache_size);
+ 
+   np = node_cache[id].np;
+@@ -174,7 +184,7 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+       dn = malloc (sizeof (struct disknode));
+       if (!dn)
+ 	{
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	  pthread_mutex_unlock (&node_cache_lock);
+ 	  release_rrip (&rr);
+ 	  return ENOMEM;
+ 	}
+@@ -185,16 +195,17 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+       if (!np)
+ 	{
+ 	  free (dn);
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	  pthread_mutex_unlock (&node_cache_lock);
+ 	  release_rrip (&rr);
+ 	  return ENOMEM;
+ 	}
+       np->cache_id = id + 1;	/* see above for rationale for increment */
+       pthread_mutex_lock (&np->lock);
+       c->np = np;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      diskfs_nref_light (np);
++      pthread_mutex_unlock (&node_cache_lock);
+ 
+-      err = read_disknode (np, node_cache[id].dr, &rr);
++      err = read_disknode (np, dn->dr, &rr);
+       if (!err)
+ 	*npp = np;
+ 
+@@ -204,8 +215,8 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+     }
+ 
+ 
+-  np->references++;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  diskfs_nref (np);
++  pthread_mutex_unlock (&node_cache_lock);
+   pthread_mutex_lock (&np->lock);
+   *npp = np;
+   return 0;
+@@ -315,7 +326,7 @@ load_inode (struct node **npp, struct dirrect *record,
+   if (rr->valid & VALID_CL)
+     record = rr->realdirent;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&node_cache_lock);
+ 
+   /* First check the cache */
+   if (use_file_start_id (record, rr))
+@@ -325,7 +336,7 @@ load_inode (struct node **npp, struct dirrect *record,
+ 
+   if (*npp)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&node_cache_lock);
+       return 0;
+     }
+ 
+@@ -333,7 +344,7 @@ load_inode (struct node **npp, struct dirrect *record,
+   dn = malloc (sizeof (struct disknode));
+   if (!dn)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&node_cache_lock);
+       return ENOMEM;
+     }
+   dn->fileinfo = 0;
+@@ -344,14 +355,14 @@ load_inode (struct node **npp, struct dirrect *record,
+   if (!np)
+     {
+       free (dn);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&node_cache_lock);
+       return ENOMEM;
+     }
+ 
+   pthread_mutex_lock (&np->lock);
+ 
+   cache_inode (np, record, rr);
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&node_cache_lock);
+ 
+   err = read_disknode (np, record, rr);
+   *npp = np;
+@@ -505,9 +516,6 @@ error_t (*diskfs_read_symlink_hook) (struct node *, char *)
+ void
+ diskfs_node_norefs (struct node *np)
+ {
+-  assert (node_cache[np->cache_id - 1].np == np);
+-  node_cache[np->cache_id - 1].np = 0;
+-
+   if (np->dn->translator)
+     free (np->dn->translator);
+ 
+@@ -521,6 +529,32 @@ diskfs_node_norefs (struct node *np)
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_mutex_lock (&node_cache_lock);
++  if (np->cache_id != 0)
++    {
++      assert (node_cache[np->cache_id - 1].np == np);
++
++      /* Check if someone reacquired a reference through the
++         node_cache.  */
++      unsigned int references;
++      pthread_spin_lock (&diskfs_node_refcnt_lock);
++      references = np->references;
++      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++      if (references > 0)
++        {
++          /* A reference was reacquired through a hash table lookup.
++             It's fine, we didn't touch anything yet. */
++          pthread_mutex_unlock (&node_cache_lock);
++          return;
++        }
++
++      node_cache[np->cache_id - 1].np = 0;
++      np->cache_id = 0;
++      diskfs_nrele_light (np);
++    }
++  pthread_mutex_unlock (&node_cache_lock);
++
+   drop_pager_softrefs (np);
+ }
+ 
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0013-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch b/debian/patches/0013-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
new file mode 100644
index 00000000..0aad79b3
--- /dev/null
+++ b/debian/patches/0013-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
@@ -0,0 +1,263 @@
+From 658f63ccaa0eb3e75f7adc3961a9039d372980fc Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 13 May 2014 15:35:42 +0200
+Subject: [PATCH 13/16] tmpfs: use a seperate lock to protect all_nodes
+
+Previously, tmpfs used diskfs_node_refcnt_lock to serialize access to
+the all_nodes and some other related global state related to memory
+consumption.
+
+Use a separate lock to protect all_nodes, and to the state related to
+memory consumption as this is updated during insertion and removal
+operations. Adjust the reference counting accordingly.  Every node in
+the all_nodes carries a light reference.  When we are asked to give up
+that light reference, we reacquire our lock momentarily to check
+whether someone else reacquired a reference through the all_nodes.
+
+* tmpfs/node.c (all_nodes_lock): New lock.
+(diskfs_alloc_node): Use a separate lock to protect all_nodes.
+Adjust the reference counting accordingly.
+(diskfs_free_node): Likewise.
+(diskfs_cached_lookup):Likewise.
+(diskfs_node_iterate): Likewise.
+(diskfs_node_norefs): Move the code removing the node from all_nodes...
+(diskfs_try_dropping_softrefs): ... here, where we check whether
+someone reacquired a reference, and if so hold on to our light
+reference.
+* tmpfs/tmpfs.c (diskfs_set_statfs): Use all_nodes_lock.
+* tmpfs/tmpfs.h (all_nodes_lock): New declaration.
+(adjust_used): Use all_nodes_lock.
+---
+ tmpfs/node.c  | 76 +++++++++++++++++++++++++++++++++++++++++++----------------
+ tmpfs/tmpfs.c |  4 ++--
+ tmpfs/tmpfs.h |  6 +++--
+ 3 files changed, 62 insertions(+), 24 deletions(-)
+
+diff --git a/tmpfs/node.c b/tmpfs/node.c
+index acc029a..74971ec 100644
+--- a/tmpfs/node.c
++++ b/tmpfs/node.c
+@@ -29,8 +29,18 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+ unsigned int num_files;
+ static unsigned int gen;
+ 
++/* all_nodes is a cache of nodes.
++
++   Access to all_nodes and all_nodes_nr_items is protected by
++   all_nodes_lock.
++
++   Every node in the all_nodes carries a light reference.  When we are
++   asked to give up that light reference, we reacquire our lock
++   momentarily to check whether someone else reacquired a reference
++   through the all_nodes.  */
+ struct node *all_nodes;
+ static size_t all_nodes_nr_items;
++pthread_mutex_t all_nodes_lock = PTHREAD_MUTEX_INITIALIZER;
+ 
+ error_t
+ diskfs_alloc_node (struct node *dp, mode_t mode, struct node **npp)
+@@ -40,18 +50,18 @@ diskfs_alloc_node (struct node *dp, mode_t mode, struct node **npp)
+   dn = calloc (1, sizeof *dn);
+   if (dn == 0)
+     return ENOSPC;
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&all_nodes_lock);
+   if (round_page (tmpfs_space_used + sizeof *dn) / vm_page_size
+       > tmpfs_page_limit)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_mutex_unlock (&all_nodes_lock);
+       free (dn);
+       return ENOSPC;
+     }
+   dn->gen = gen++;
+   ++num_files;
+   tmpfs_space_used += sizeof *dn;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&all_nodes_lock);
+ 
+   dn->type = IFTODT (mode & S_IFMT);
+   return diskfs_cached_lookup ((ino_t) (uintptr_t) dn, npp);
+@@ -75,15 +85,18 @@ diskfs_free_node (struct node *np, mode_t mode)
+       free (np->dn->u.lnk);
+       break;
+     }
++
++  pthread_mutex_lock (&all_nodes_lock);
+   *np->dn->hprevp = np->dn->hnext;
+   if (np->dn->hnext != 0)
+     np->dn->hnext->dn->hprevp = np->dn->hprevp;
+   all_nodes_nr_items -= 1;
+-  free (np->dn);
+-  np->dn = 0;
+-
+   --num_files;
+   tmpfs_space_used -= sizeof *np->dn;
++  pthread_mutex_unlock (&all_nodes_lock);
++
++  free (np->dn);
++  np->dn = 0;
+ }
+ 
+ void
+@@ -117,14 +130,6 @@ diskfs_node_norefs (struct node *np)
+ 	  np->dn->u.chr = np->dn_stat.st_rdev;
+ 	  break;
+ 	}
+-
+-      /* Remove this node from the cache list rooted at `all_nodes'.  */
+-      *np->dn->hprevp = np->dn->hnext;
+-      if (np->dn->hnext != 0)
+-	np->dn->hnext->dn->hprevp = np->dn->hprevp;
+-      all_nodes_nr_items -= 1;
+-      np->dn->hnext = 0;
+-      np->dn->hprevp = 0;
+     }
+ 
+   free (np);
+@@ -167,11 +172,14 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+ 
+   assert (npp);
+ 
++  pthread_mutex_lock (&all_nodes_lock);
++
+   if (dn->hprevp != 0)		/* There is already a node.  */
+     {
+       np = *dn->hprevp;
+       assert (np->dn == dn);
+       assert (*dn->hprevp == np);
++      pthread_mutex_unlock (&all_nodes_lock);
+ 
+       diskfs_nref (np);
+     }
+@@ -183,14 +191,14 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+       np = diskfs_make_node (dn);
+       np->cache_id = (ino_t) (uintptr_t) dn;
+ 
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+       dn->hnext = all_nodes;
+       if (dn->hnext)
+ 	dn->hnext->dn->hprevp = &dn->hnext;
+       dn->hprevp = &all_nodes;
+       all_nodes = np;
+       all_nodes_nr_items += 1;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      diskfs_nref_light (np);
++      pthread_mutex_unlock (&all_nodes_lock);
+ 
+       st = &np->dn_stat;
+       memset (st, 0, sizeof *st);
+@@ -229,12 +237,12 @@ diskfs_node_iterate (error_t (*fun) (struct node *))
+   size_t num_nodes;
+   struct node *node, **node_list, **p;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&all_nodes_lock);
+ 
+   /* We must copy everything from the hash table into another data structure
+      to avoid running into any problems with the hash-table being modified
+      during processing (normally we delegate access to hash-table with
+-     diskfs_node_refcnt_lock, but we can't hold this while locking the
++     all_nodes_lock, but we can't hold this while locking the
+      individual node locks).  */
+ 
+   num_nodes = all_nodes_nr_items;
+@@ -243,10 +251,10 @@ diskfs_node_iterate (error_t (*fun) (struct node *))
+   for (node = all_nodes; node != 0; node = node->dn->hnext)
+     {
+       *p++ = node;
+-      node->references++;
++      diskfs_nref (node);
+     }
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&all_nodes_lock);
+ 
+   p = node_list;
+   while (num_nodes-- > 0)
+@@ -272,6 +280,34 @@ diskfs_node_iterate (error_t (*fun) (struct node *))
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_mutex_lock (&all_nodes_lock);
++  if (np->dn->hnext != NULL)
++    {
++      /* Check if someone reacquired a reference through the
++         all_nodes.  */
++      unsigned int references;
++      pthread_spin_lock (&diskfs_node_refcnt_lock);
++      references = np->references;
++      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++      if (references > 0)
++        {
++          /* A reference was reacquired through a hash table lookup.
++             It's fine, we didn't touch anything yet. */
++          pthread_mutex_unlock (&all_nodes_lock);
++          return;
++        }
++
++      /* Remove this node from the cache list rooted at `all_nodes'.  */
++      *np->dn->hprevp = np->dn->hnext;
++      if (np->dn->hnext != 0)
++	np->dn->hnext->dn->hprevp = np->dn->hprevp;
++      all_nodes_nr_items -= 1;
++      np->dn->hnext = NULL;
++      np->dn->hprevp = NULL;
++      diskfs_nrele_light (np);
++    }
++  pthread_mutex_unlock (&all_nodes_lock);
+ }
+ 
+ /* The user must define this funcction.  Node NP has some light
+diff --git a/tmpfs/tmpfs.c b/tmpfs/tmpfs.c
+index a45d343..024b818 100644
+--- a/tmpfs/tmpfs.c
++++ b/tmpfs/tmpfs.c
+@@ -67,10 +67,10 @@ diskfs_set_statfs (struct statfs *st)
+   st->f_bsize = vm_page_size;
+   st->f_blocks = tmpfs_page_limit;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&all_nodes_lock);
+   st->f_files = num_files;
+   pages = round_page (tmpfs_space_used) / vm_page_size;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&all_nodes_lock);
+ 
+   st->f_bfree = pages < tmpfs_page_limit ? tmpfs_page_limit - pages : 0;
+   st->f_bavail = st->f_bfree;
+diff --git a/tmpfs/tmpfs.h b/tmpfs/tmpfs.h
+index b3c636d..187249e 100644
+--- a/tmpfs/tmpfs.h
++++ b/tmpfs/tmpfs.h
+@@ -24,6 +24,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+ #include <sys/types.h>
+ #include <dirent.h>
+ #include <stdint.h>
++#include <pthread.h>
+ 
+ struct disknode
+ {
+@@ -71,15 +72,16 @@ struct tmpfs_dirent
+ 
+ extern unsigned int num_files;
+ extern off_t tmpfs_page_limit, tmpfs_space_used;
++extern pthread_mutex_t all_nodes_lock;
+ 
+ extern mach_port_t default_pager;
+ 
+ static inline void
+ adjust_used (off_t change)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
++  pthread_mutex_lock (&all_nodes_lock);
+   tmpfs_space_used += change;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_mutex_unlock (&all_nodes_lock);
+ }
+ 
+ #endif
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0014-libdiskfs-lock-less-reference-counting-of-nodes.patch b/debian/patches/0014-libdiskfs-lock-less-reference-counting-of-nodes.patch
new file mode 100644
index 00000000..8be6f86d
--- /dev/null
+++ b/debian/patches/0014-libdiskfs-lock-less-reference-counting-of-nodes.patch
@@ -0,0 +1,531 @@
+From b4b202e088775047117b2fd4dc0eaf4c7e788d52 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Wed, 14 May 2014 11:19:35 +0200
+Subject: [PATCH 14/16] libdiskfs: lock-less reference counting of nodes
+
+* libdiskfs/diskfs.h (struct node): Use refcounts_t for reference counting.
+(diskfs_node_refcnt_lock): Remove.
+(diskfs_node_norefs,diskfs_drop_node): Change comments accordingly.
+* libdiskfs/init-init.c: Likewise.
+* libdiskfs/node-drop.c: Likewise.
+* libdiskfs/node-make.c: Likewise.
+* libdiskfs/node-nput.c: Likewise.
+* libdiskfs/node-nputl.c: Likewise.
+* libdiskfs/node-nref.c: Likewise.
+* libdiskfs/node-nrefl.c: Likewise.
+* libdiskfs/node-nrele.c: Likewise.
+* libdiskfs/node-nrelel.c: Likewise.
+* ext2fs/inode.c: Likewise.
+* fatfs/inode.c: Likewise.
+* isofs/inode.c: Likewise.
+* tmpfs/node.c: Likewise.
+* doc/hurd.texi: Likewise.
+---
+ doc/hurd.texi           | 11 ++--------
+ ext2fs/inode.c          |  9 +++------
+ fatfs/inode.c           | 21 ++++++-------------
+ isofs/inode.c           |  9 +++------
+ libdiskfs/diskfs.h      | 12 ++++-------
+ libdiskfs/init-init.c   |  2 --
+ libdiskfs/node-drop.c   |  9 +++------
+ libdiskfs/node-make.c   |  3 +--
+ libdiskfs/node-nput.c   | 54 +++++++++++++++++++------------------------------
+ libdiskfs/node-nputl.c  | 12 ++++-------
+ libdiskfs/node-nref.c   | 10 ++++-----
+ libdiskfs/node-nrefl.c  |  6 +++---
+ libdiskfs/node-nrele.c  | 48 +++++++++++++++++++++----------------------
+ libdiskfs/node-nrelel.c |  9 +++------
+ tmpfs/node.c            |  9 +++------
+ 15 files changed, 83 insertions(+), 141 deletions(-)
+
+diff --git a/doc/hurd.texi b/doc/hurd.texi
+index 07ddfb4..6cafdb9 100644
+--- a/doc/hurd.texi
++++ b/doc/hurd.texi
+@@ -3780,10 +3780,6 @@ new thread and (eventually) get rid of the old one; the old thread won't
+ do any more syncs, regardless.
+ @end deftypefun
+ 
+-@deftypevar spin_lock_t diskfs_node_refcnt_lock
+-Pager reference count lock.
+-@end deftypevar
+-
+ @deftypevar int diskfs_readonly
+ Set to zero if the filesystem is currently writable.
+ @end deftypevar
+@@ -3818,9 +3814,7 @@ Every file or directory is a diskfs @dfn{node}.  The following functions
+ help your diskfs callbacks manage nodes and their references:
+ 
+ @deftypefun void diskfs_drop_node (@w{struct node *@var{np}})
+-Node @var{np} now has no more references; clean all state.  The
+-@var{diskfs_node_refcnt_lock} must be held, and will be released upon
+-return.  @var{np} must be locked.
++Node @var{np} now has no more references; clean all state.
+ @end deftypefun
+ 
+ @deftypefun void diskfs_node_update (@w{struct node *@var{np}}, @w{int @var{wait}})
+@@ -4236,14 +4230,13 @@ without real users.
+ @deftypefun void diskfs_try_dropping_softrefs (@w{struct node *@var{np}})
+ Node @var{np} has some light references, but has just lost its last hard
+ references.  Take steps so that if any light references can be freed,
+-they are.  Both @var{diskfs_node_refcnt_lock} and @var{np} are locked.
++they are.  @var{np} is locked.
+ This function will be called after @code{diskfs_lost_hardrefs}.
+ @end deftypefun
+ 
+ @deftypefun void diskfs_node_norefs (@w{struct node *@var{np}})
+ Node @var{np} has no more references; free local state, including
+ @code{*@var{np}} if it shouldn't be retained.
+-@var{diskfs_node_refcnt_lock} is held.
+ @end deftypefun
+ 
+ @deftypefun error_t diskfs_set_hypermetadata (@w{int @var{wait}}, @w{int @var{clean}})
+diff --git a/ext2fs/inode.c b/ext2fs/inode.c
+index aa070a2..7ec343f 100644
+--- a/ext2fs/inode.c
++++ b/ext2fs/inode.c
+@@ -190,12 +190,9 @@ diskfs_try_dropping_softrefs (struct node *np)
+     {
+       /* Check if someone reacquired a reference through the
+          nodehash.  */
+-      unsigned int references;
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+-      references = np->references;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+-      if (references > 0)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++      if (result.hard > 0 || result.weak > 1)
+         {
+           /* A reference was reacquired through a hash table lookup.
+              It's fine, we didn't touch anything yet. */
+diff --git a/fatfs/inode.c b/fatfs/inode.c
+index 8b3385b..d5750b4 100644
+--- a/fatfs/inode.c
++++ b/fatfs/inode.c
+@@ -237,14 +237,8 @@ diskfs_node_norefs (struct node *np)
+   if (np->dn->translator)
+     free (np->dn->translator);
+ 
+-  /* It is safe to unlock diskfs_node_refcnt_lock here for a while because
+-     all references to the node have been deleted.  */
+   if (np->dn->dirnode)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      diskfs_nrele (np->dn->dirnode);
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+-    }
++    diskfs_nrele (np->dn->dirnode);
+ 
+   assert (!np->dn->pager);
+ 
+@@ -262,12 +256,9 @@ diskfs_try_dropping_softrefs (struct node *np)
+     {
+       /* Check if someone reacquired a reference through the
+          nodehash.  */
+-      unsigned int references;
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+-      references = np->references;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+-      if (references > 0)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++      if (result.hard > 0 || result.weak > 1)
+         {
+           /* A reference was reacquired through a hash table lookup.
+              It's fine, we didn't touch anything yet. */
+@@ -372,7 +363,7 @@ read_node (struct node *np, vm_address_t buf)
+   /* Files in fatfs depend on the directory that hold the file.  */
+   np->dn->dirnode = dp;
+   if (dp)
+-    dp->references++;
++    refcounts_ref (&dp->refcounts, NULL);
+ 
+   pthread_rwlock_rdlock (&np->dn->dirent_lock);
+ 
+@@ -814,7 +805,7 @@ diskfs_alloc_node (struct node *dir, mode_t mode, struct node **node)
+ 
+   /* FIXME: We know that readnode couldn't put this in.  */
+   np->dn->dirnode = dir;
+-  dir->references++;
++  refcounts_ref (&dir->refcounts, NULL);
+ 
+   *node = np;
+   return 0;
+diff --git a/isofs/inode.c b/isofs/inode.c
+index 4f22086..b36a289 100644
+--- a/isofs/inode.c
++++ b/isofs/inode.c
+@@ -536,12 +536,9 @@ diskfs_try_dropping_softrefs (struct node *np)
+ 
+       /* Check if someone reacquired a reference through the
+          node_cache.  */
+-      unsigned int references;
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+-      references = np->references;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+-      if (references > 0)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++      if (result.hard > 0 || result.weak > 1)
+         {
+           /* A reference was reacquired through a hash table lookup.
+              It's fine, we didn't touch anything yet. */
+diff --git a/libdiskfs/diskfs.h b/libdiskfs/diskfs.h
+index acd1910..e10e75e 100644
+--- a/libdiskfs/diskfs.h
++++ b/libdiskfs/diskfs.h
+@@ -96,8 +96,7 @@ struct node
+ 
+   pthread_mutex_t lock;
+ 
+-  int references;		/* hard references */
+-  int light_references;		/* light references */
++  refcounts_t refcounts;
+ 
+   mach_port_t sockaddr;		/* address for S_IFSOCK shortcut */
+ 
+@@ -201,8 +200,6 @@ extern volatile struct mapped_time_value *diskfs_mtime;
+    be done by format independent code. */
+ extern int diskfs_synchronous;
+ 
+-extern pthread_spinlock_t diskfs_node_refcnt_lock;
+-
+ extern int pager_port_type;
+ 
+ /* Whether the filesystem is currently writable or not. */
+@@ -451,7 +448,7 @@ error_t diskfs_alloc_node (struct node *dp, mode_t mode, struct node **np);
+ void diskfs_free_node (struct node *np, mode_t mode);
+ 
+ /* Node NP has no more references; free local state, including *NP
+-   if it isn't to be retained.  diskfs_node_refcnt_lock is held. */
++   if it isn't to be retained.  */
+ void diskfs_node_norefs (struct node *np);
+ 
+ /* The user must define this function.  Node NP has some light
+@@ -614,9 +611,8 @@ void diskfs_spawn_first_thread (ports_demuxer_type demuxer);
+    diskfs_init_completed once it has a valid proc and auth port. */
+ void diskfs_start_bootstrap ();
+ 
+-/* Node NP now has no more references; clean all state.  The
+-   _diskfs_node_refcnt_lock must be held, and will be released
+-   upon return.  NP must be locked.  */
++/* Node NP now has no more references; clean all state.  NP must be
++   locked.  */
+ void diskfs_drop_node (struct node *np);
+ 
+ /* Set on disk fields from NP->dn_stat; update ctime, atime, and mtime
+diff --git a/libdiskfs/init-init.c b/libdiskfs/init-init.c
+index 35be7ed..976b4e8 100644
+--- a/libdiskfs/init-init.c
++++ b/libdiskfs/init-init.c
+@@ -37,8 +37,6 @@ int _diskfs_noatime;
+ 
+ struct hurd_port _diskfs_exec_portcell;
+ 
+-pthread_spinlock_t diskfs_node_refcnt_lock = PTHREAD_SPINLOCK_INITIALIZER;
+-
+ pthread_spinlock_t _diskfs_control_lock = PTHREAD_SPINLOCK_INITIALIZER;
+ int _diskfs_ncontrol_ports;
+ 
+diff --git a/libdiskfs/node-drop.c b/libdiskfs/node-drop.c
+index 83eb590..fab3cfa 100644
+--- a/libdiskfs/node-drop.c
++++ b/libdiskfs/node-drop.c
+@@ -31,9 +31,8 @@ free_modreqs (struct modreq *mr)
+ }
+ 
+ 
+-/* Node NP now has no more references; clean all state.  The
+-   diskfs_node_refcnt_lock must be held, and will be released
+-   upon return.  NP must be locked.  */
++/* Node NP now has no more references; clean all state.  NP must be
++   locked.  */
+ void
+ diskfs_drop_node (struct node *np)
+ {
+@@ -60,8 +59,7 @@ diskfs_drop_node (struct node *np)
+ 	     and an nput.  The next time through, this routine
+ 	     will notice that the size is zero, and not have to
+ 	     do anything. */
+-	  np->references++;
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	  refcounts_ref (&np->refcounts, NULL);
+ 	  diskfs_truncate (np, 0);
+ 	  
+ 	  /* Force allocsize to zero; if truncate consistently fails this
+@@ -94,5 +92,4 @@ diskfs_drop_node (struct node *np)
+   assert (!np->sockaddr);
+ 
+   diskfs_node_norefs (np);
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+ }
+diff --git a/libdiskfs/node-make.c b/libdiskfs/node-make.c
+index ff0cc0d..c7ca3b0 100644
+--- a/libdiskfs/node-make.c
++++ b/libdiskfs/node-make.c
+@@ -29,8 +29,7 @@ init_node (struct node *np, struct disknode *dn)
+   np->dn_stat_dirty = 0;
+ 
+   pthread_mutex_init (&np->lock, NULL);
+-  np->references = 1;
+-  np->light_references = 0;
++  refcounts_init (&np->refcounts, 1, 0);
+   np->owner = 0;
+   np->sockaddr = MACH_PORT_NULL;
+ 
+diff --git a/libdiskfs/node-nput.c b/libdiskfs/node-nput.c
+index 5043ad1..2935ae2 100644
+--- a/libdiskfs/node-nput.c
++++ b/libdiskfs/node-nput.c
+@@ -26,56 +26,44 @@
+ void
+ diskfs_nput (struct node *np)
+ {
+-  int tried_drop_softrefs = 0;
++  struct references result;
+ 
+- loop:
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->references);
+-  np->references--;
+-  if (np->references + np->light_references == 0)
+-    diskfs_drop_node (np);
+-  else if (np->references == 0 && !tried_drop_softrefs)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  /* While we call the diskfs_try_dropping_softrefs, we need to hold
++     one reference.  We use a weak reference for this purpose, which
++     we acquire by demoting our hard reference to a weak one.  */
++  refcounts_demote (&np->refcounts, &result);
+ 
++  if (result.hard == 0)
++    {
+       /* This is our cue that something akin to "last process closes file"
+ 	 in the POSIX.1 sense happened, so make sure any pending node time
+ 	 updates now happen in a timely fashion.  */
+       diskfs_set_node_times (np);
+-
+       diskfs_lost_hardrefs (np);
+       if (!np->dn_stat.st_nlink)
+ 	{
+-	  /* There are no links.  If there are soft references that
+-	     can be dropped, we can't let them postpone deallocation.
+-	     So attempt to drop them.  But that's a user-supplied
+-	     routine, which might result in further recursive calls to
+-	     the ref-counting system.  So we have to reacquire our
+-	     reference around the call to forestall disaster. */
+-	  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-	  np->references++;
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+ 	  if (np->sockaddr != MACH_PORT_NULL)
+ 	    {
+ 	      mach_port_deallocate (mach_task_self (), np->sockaddr);
+ 	      np->sockaddr = MACH_PORT_NULL;
+ 	    }
+ 
++	  /* There are no links.  If there are soft references that
++	     can be dropped, we can't let them postpone deallocation.
++	     So attempt to drop them.  But that's a user-supplied
++	     routine, which might result in further recursive calls to
++	     the ref-counting system.  This is not a problem, as we
++	     hold a weak reference ourselves. */
+ 	  diskfs_try_dropping_softrefs (np);
+-
+-	  /* But there's no value in looping forever in this
+-	     routine; only try to drop soft refs once. */
+-	  tried_drop_softrefs = 1;
+-
+-	  /* Now we can drop the reference back... */
+-	  goto loop;
+ 	}
+       pthread_mutex_unlock (&np->lock);
+     }
+-  else
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      pthread_mutex_unlock (&np->lock);
+-    }
++
++  /* Finally get rid of our reference.  */
++  refcounts_deref_weak (&np->refcounts, &result);
++
++  if (result.hard == 0 && result.weak == 0)
++    diskfs_drop_node (np);
++
++  pthread_mutex_unlock (&np->lock);
+ }
+diff --git a/libdiskfs/node-nputl.c b/libdiskfs/node-nputl.c
+index 1959665..8dac16e 100644
+--- a/libdiskfs/node-nputl.c
++++ b/libdiskfs/node-nputl.c
+@@ -25,14 +25,10 @@
+ void
+ diskfs_nput_light (struct node *np)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->light_references);
+-  np->light_references--;
+-  if (np->references + np->light_references == 0)
++  struct references result;
++  refcounts_deref_weak (&np->refcounts, &result);
++  if (result.hard == 0 && result.weak == 0)
+     diskfs_drop_node (np);
+   else
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      pthread_mutex_unlock (&np->lock);
+-    }
++    pthread_mutex_unlock (&np->lock);
+ }
+diff --git a/libdiskfs/node-nref.c b/libdiskfs/node-nref.c
+index 13cea05..89ffa4f 100644
+--- a/libdiskfs/node-nref.c
++++ b/libdiskfs/node-nref.c
+@@ -26,12 +26,10 @@
+ void
+ diskfs_nref (struct node *np)
+ {
+-  int new_hardref;
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  np->references++;
+-  new_hardref = (np->references == 1);
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-  if (new_hardref)
++  struct references result;
++  refcounts_ref (&np->refcounts, &result);
++  assert (result.hard > 1 || result.weak > 0);
++  if (result.hard == 1)
+     {
+       pthread_mutex_lock (&np->lock);
+       diskfs_new_hardrefs (np);
+diff --git a/libdiskfs/node-nrefl.c b/libdiskfs/node-nrefl.c
+index 9692247..b7af409 100644
+--- a/libdiskfs/node-nrefl.c
++++ b/libdiskfs/node-nrefl.c
+@@ -24,7 +24,7 @@
+ void
+ diskfs_nref_light (struct node *np)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  np->light_references++;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  struct references result;
++  refcounts_ref_weak (&np->refcounts, &result);
++  assert (result.hard > 0 || result.weak > 1);
+ }
+diff --git a/libdiskfs/node-nrele.c b/libdiskfs/node-nrele.c
+index cc68089..d962846 100644
+--- a/libdiskfs/node-nrele.c
++++ b/libdiskfs/node-nrele.c
+@@ -28,38 +28,36 @@
+ void
+ diskfs_nrele (struct node *np)
+ {
+-  int tried_drop_softrefs = 0;
++  struct references result;
+ 
+- loop:
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->references);
+-  np->references--;
+-  if (np->references + np->light_references == 0)
+-    {
+-      pthread_mutex_lock (&np->lock);
+-      diskfs_drop_node (np);
+-    }
+-  else if (np->references == 0)
++  /* While we call the diskfs_try_dropping_softrefs, we need to hold
++     one reference.  We use a weak reference for this purpose, which
++     we acquire by demoting our hard reference to a weak one.  */
++  refcounts_demote (&np->refcounts, &result);
++
++  if (result.hard == 0)
+     {
+       pthread_mutex_lock (&np->lock);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+       diskfs_lost_hardrefs (np);
+-      if (!np->dn_stat.st_nlink && !tried_drop_softrefs)
++      if (!np->dn_stat.st_nlink)
+ 	{
+-	  /* Same issue here as in nput; see that for explanation */
+-	  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-	  np->references++;
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
++	  /* There are no links.  If there are soft references that
++	     can be dropped, we can't let them postpone deallocation.
++	     So attempt to drop them.  But that's a user-supplied
++	     routine, which might result in further recursive calls to
++	     the ref-counting system.  This is not a problem, as we
++	     hold a weak reference ourselves. */
+ 	  diskfs_try_dropping_softrefs (np);
+-	  tried_drop_softrefs = 1;
+-
+-	  /* Now we can drop the reference back... */
+-	  pthread_mutex_unlock (&np->lock);
+-	  goto loop;
+ 	}
+       pthread_mutex_unlock (&np->lock);
+     }
+-  else
+-    pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++  /* Finally get rid of our reference.  */
++  refcounts_deref_weak (&np->refcounts, &result);
++
++  if (result.hard == 0 && result.weak == 0)
++    {
++      pthread_mutex_lock (&np->lock);
++      diskfs_drop_node (np);
++    }
+ }
+diff --git a/libdiskfs/node-nrelel.c b/libdiskfs/node-nrelel.c
+index ee53b22..dc4f920 100644
+--- a/libdiskfs/node-nrelel.c
++++ b/libdiskfs/node-nrelel.c
+@@ -26,14 +26,11 @@
+ void
+ diskfs_nrele_light (struct node *np)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->light_references);
+-  np->light_references--;
+-  if (np->references + np->light_references == 0)
++  struct references result;
++  refcounts_deref_weak (&np->refcounts, &result);
++  if (result.hard == 0 && result.weak == 0)
+     {
+       pthread_mutex_lock (&np->lock);
+       diskfs_drop_node (np);
+     }
+-  else
+-    pthread_spin_unlock (&diskfs_node_refcnt_lock);
+ }
+diff --git a/tmpfs/node.c b/tmpfs/node.c
+index 74971ec..275bb3c 100644
+--- a/tmpfs/node.c
++++ b/tmpfs/node.c
+@@ -285,12 +285,9 @@ diskfs_try_dropping_softrefs (struct node *np)
+     {
+       /* Check if someone reacquired a reference through the
+          all_nodes.  */
+-      unsigned int references;
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+-      references = np->references;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+-      if (references > 0)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++      if (result.hard > 0 || result.weak > 1)
+         {
+           /* A reference was reacquired through a hash table lookup.
+              It's fine, we didn't touch anything yet. */
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0015-librbtree-add-a-red-black-tree-implementation.patch b/debian/patches/0015-librbtree-add-a-red-black-tree-implementation.patch
new file mode 100644
index 00000000..9206f00a
--- /dev/null
+++ b/debian/patches/0015-librbtree-add-a-red-black-tree-implementation.patch
@@ -0,0 +1,1182 @@
+From 4a90b62d7790c4bf8f9b0b352566f44e00df19ec Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Fri, 16 May 2014 20:21:48 +0200
+Subject: [PATCH 15/16] librbtree: add a red-black tree implementation
+
+Red-black trees offer search, insert, and delete operations with worst
+case runtime in O(log n).  They are also very space efficient.
+
+This is an verbatim copy from git://git.sceen.net/rbraun/librbraun.git
+as of 45fef4ad.  Only macros.h has been slightly amended.  This file
+defines two macros, which are also defined in cthreads.h.  Undefine
+the macros first to work around this problem.
+
+* librbtree/Makefile: New file.
+* librbtree/rbtree.c: Likewise.
+* librbtree/rbtree.h: Likewise.
+* librbtree/rbtree_i.h: Likewise.
+* librbtree/macros.h: Likewise.  Also, undefine MACRO_{BEGIN,END}.
+* Makefile (lib-subdirs): Add librbtree.
+---
+ Makefile             |   4 +-
+ librbtree/Makefile   |  27 +++
+ librbtree/macros.h   |  70 ++++++++
+ librbtree/rbtree.c   | 498 +++++++++++++++++++++++++++++++++++++++++++++++++++
+ librbtree/rbtree.h   | 310 ++++++++++++++++++++++++++++++++
+ librbtree/rbtree_i.h | 196 ++++++++++++++++++++
+ 6 files changed, 1103 insertions(+), 2 deletions(-)
+ create mode 100644 librbtree/Makefile
+ create mode 100644 librbtree/macros.h
+ create mode 100644 librbtree/rbtree.c
+ create mode 100644 librbtree/rbtree.h
+ create mode 100644 librbtree/rbtree_i.h
+
+diff --git a/Makefile b/Makefile
+index 106f2f6..c85a55a 100644
+--- a/Makefile
++++ b/Makefile
+@@ -26,8 +26,8 @@ include ./Makeconf
+ ## Subdirectories of this directory should all be mentioned here
+ 
+ # Hurd libraries
+-lib-subdirs = libshouldbeinlibc libihash libiohelp libports libthreads \
+-	      libpager libfshelp libdiskfs libtrivfs libps \
++lib-subdirs = libshouldbeinlibc libihash librbtree libiohelp libports \
++	      libthreads libpager libfshelp libdiskfs libtrivfs libps \
+ 	      libnetfs libpipe libstore libhurdbugaddr libftpconn libcons
+ 
+ # Hurd programs
+diff --git a/librbtree/Makefile b/librbtree/Makefile
+new file mode 100644
+index 0000000..0f33358
+--- /dev/null
++++ b/librbtree/Makefile
+@@ -0,0 +1,27 @@
++#   Copyright (C) 2014 Free Software Foundation, Inc.
++#
++#   This file is part of the GNU Hurd.
++#
++#   The GNU Hurd is free software; you can redistribute it and/or
++#   modify it under the terms of the GNU General Public License as
++#   published by the Free Software Foundation; either version 2, or (at
++#   your option) any later version.
++#
++#   The GNU Hurd is distributed in the hope that it will be useful, but
++#   WITHOUT ANY WARRANTY; without even the implied warranty of
++#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++#   General Public License for more details.
++#
++#   You should have received a copy of the GNU General Public License
++#   along with the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.
++
++dir := librbtree
++makemode := library
++
++libname := librbtree
++SRCS = rbtree.c
++installhdrs = rbtree.h rbtree_i.h macros.h
++
++OBJS = $(SRCS:.c=.o)
++
++include ../Makeconf
+diff --git a/librbtree/macros.h b/librbtree/macros.h
+new file mode 100644
+index 0000000..f0960a3
+--- /dev/null
++++ b/librbtree/macros.h
+@@ -0,0 +1,70 @@
++/*
++ * Copyright (c) 2009, 2010 Richard Braun.
++ * All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ *
++ *
++ * Helper macros.
++ */
++
++#ifndef _MACROS_H
++#define _MACROS_H
++
++#include <stddef.h>
++
++#undef MACRO_BEGIN
++#undef MACRO_END
++#define MACRO_BEGIN     ({
++#define MACRO_END       })
++
++#define XQUOTE(x)       #x
++#define QUOTE(x)        XQUOTE(x)
++
++#define STRLEN(x)       (sizeof(x) - 1)
++#define ARRAY_SIZE(x)   (sizeof(x) / sizeof((x)[0]))
++
++#define MIN(a, b)       ((a) < (b) ? (a) : (b))
++#define MAX(a, b)       ((a) > (b) ? (a) : (b))
++
++#define P2ALIGNED(x, a) (((x) & ((a) - 1)) == 0)
++#define ISP2(x)         P2ALIGNED(x, x)
++#define P2ALIGN(x, a)   ((x) & -(a))
++#define P2ROUND(x, a)   (-(-(x) & -(a)))
++#define P2END(x, a)     (-(~(x) & -(a)))
++
++#define structof(ptr, type, member) \
++    ((type *)((char *)(ptr) - offsetof(type, member)))
++
++#define alignof(x)      __alignof__(x)
++
++#define likely(expr)    __builtin_expect(!!(expr), 1)
++#define unlikely(expr)  __builtin_expect(!!(expr), 0)
++
++#define barrier()       asm volatile("" : : : "memory")
++
++#define __noreturn      __attribute__((noreturn))
++#define __aligned(x)    __attribute__((aligned(x)))
++
++#define __format_printf(fmt, args) \
++    __attribute__((format(printf, fmt, args)))
++
++#endif /* _MACROS_H */
+diff --git a/librbtree/rbtree.c b/librbtree/rbtree.c
+new file mode 100644
+index 0000000..969a18d
+--- /dev/null
++++ b/librbtree/rbtree.c
+@@ -0,0 +1,498 @@
++/*
++ * Copyright (c) 2010, 2012 Richard Braun.
++ * All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ */
++
++#include <assert.h>
++#include <stddef.h>
++
++#include "macros.h"
++#include "rbtree.h"
++#include "rbtree_i.h"
++
++/*
++ * Return the index of a node in the children array of its parent.
++ *
++ * The parent parameter must not be NULL, and must be the parent of the
++ * given node.
++ */
++static inline int
++rbtree_node_index(const struct rbtree_node *node,
++                  const struct rbtree_node *parent)
++{
++    assert(parent != NULL);
++    assert((node == NULL) || (rbtree_node_parent(node) == parent));
++
++    if (parent->children[RBTREE_LEFT] == node)
++        return RBTREE_LEFT;
++
++    assert(parent->children[RBTREE_RIGHT] == node);
++
++    return RBTREE_RIGHT;
++}
++
++/*
++ * Return the color of a node.
++ */
++static inline int
++rbtree_node_color(const struct rbtree_node *node)
++{
++    return node->parent & RBTREE_COLOR_MASK;
++}
++
++/*
++ * Return true if the node is red.
++ */
++static inline int
++rbtree_node_is_red(const struct rbtree_node *node)
++{
++    return rbtree_node_color(node) == RBTREE_COLOR_RED;
++}
++
++/*
++ * Return true if the node is black.
++ */
++static inline int
++rbtree_node_is_black(const struct rbtree_node *node)
++{
++    return rbtree_node_color(node) == RBTREE_COLOR_BLACK;
++}
++
++/*
++ * Set the parent of a node, retaining its current color.
++ */
++static inline void
++rbtree_node_set_parent(struct rbtree_node *node, struct rbtree_node *parent)
++{
++    assert(rbtree_node_check_alignment(node));
++    assert(rbtree_node_check_alignment(parent));
++
++    node->parent = (unsigned long)parent | (node->parent & RBTREE_COLOR_MASK);
++}
++
++/*
++ * Set the color of a node, retaining its current parent.
++ */
++static inline void
++rbtree_node_set_color(struct rbtree_node *node, int color)
++{
++    assert((color & ~RBTREE_COLOR_MASK) == 0);
++    node->parent = (node->parent & RBTREE_PARENT_MASK) | color;
++}
++
++/*
++ * Set the color of a node to red, retaining its current parent.
++ */
++static inline void
++rbtree_node_set_red(struct rbtree_node *node)
++{
++    rbtree_node_set_color(node, RBTREE_COLOR_RED);
++}
++
++/*
++ * Set the color of a node to black, retaining its current parent.
++ */
++static inline void
++rbtree_node_set_black(struct rbtree_node *node)
++{
++    rbtree_node_set_color(node, RBTREE_COLOR_BLACK);
++}
++
++/*
++ * Return the left-most deepest child node of the given node.
++ */
++static struct rbtree_node *
++rbtree_node_find_deepest(struct rbtree_node *node)
++{
++    struct rbtree_node *parent;
++
++    assert(node != NULL);
++
++    for (;;) {
++        parent = node;
++        node = node->children[RBTREE_LEFT];
++
++        if (node == NULL) {
++            node = parent->children[RBTREE_RIGHT];
++
++            if (node == NULL)
++                return parent;
++        }
++    }
++}
++
++/*
++ * Perform a tree rotation, rooted at the given node.
++ *
++ * The direction parameter defines the rotation direction and is either
++ * RBTREE_LEFT or RBTREE_RIGHT.
++ */
++static void
++rbtree_rotate(struct rbtree *tree, struct rbtree_node *node, int direction)
++{
++    struct rbtree_node *parent, *rnode;
++    int left, right;
++
++    left = direction;
++    right = 1 - left;
++    parent = rbtree_node_parent(node);
++    rnode = node->children[right];
++
++    node->children[right] = rnode->children[left];
++
++    if (rnode->children[left] != NULL)
++        rbtree_node_set_parent(rnode->children[left], node);
++
++    rnode->children[left] = node;
++    rbtree_node_set_parent(rnode, parent);
++
++    if (unlikely(parent == NULL))
++        tree->root = rnode;
++    else
++        parent->children[rbtree_node_index(node, parent)] = rnode;
++
++    rbtree_node_set_parent(node, rnode);
++}
++
++void
++rbtree_insert_rebalance(struct rbtree *tree, struct rbtree_node *parent,
++                        int index, struct rbtree_node *node)
++{
++    struct rbtree_node *grand_parent, *uncle, *tmp;
++    int left, right;
++
++    assert(rbtree_node_check_alignment(parent));
++    assert(rbtree_node_check_alignment(node));
++
++    node->parent = (unsigned long)parent | RBTREE_COLOR_RED;
++    node->children[RBTREE_LEFT] = NULL;
++    node->children[RBTREE_RIGHT] = NULL;
++
++    if (unlikely(parent == NULL))
++        tree->root = node;
++    else
++        parent->children[index] = node;
++
++    for (;;) {
++        if (parent == NULL) {
++            rbtree_node_set_black(node);
++            break;
++        }
++
++        if (rbtree_node_is_black(parent))
++            break;
++
++        grand_parent = rbtree_node_parent(parent);
++        assert(grand_parent != NULL);
++
++        left = rbtree_node_index(parent, grand_parent);
++        right = 1 - left;
++
++        uncle = grand_parent->children[right];
++
++        /*
++         * Uncle is red. Flip colors and repeat at grand parent.
++         */
++        if ((uncle != NULL) && rbtree_node_is_red(uncle)) {
++            rbtree_node_set_black(uncle);
++            rbtree_node_set_black(parent);
++            rbtree_node_set_red(grand_parent);
++            node = grand_parent;
++            parent = rbtree_node_parent(node);
++            continue;
++        }
++
++        /*
++         * Node is the right child of its parent. Rotate left at parent.
++         */
++        if (parent->children[right] == node) {
++            rbtree_rotate(tree, parent, left);
++            tmp = node;
++            node = parent;
++            parent = tmp;
++        }
++
++        /*
++         * Node is the left child of its parent. Handle colors, rotate right
++         * at grand parent, and leave.
++         */
++        rbtree_node_set_black(parent);
++        rbtree_node_set_red(grand_parent);
++        rbtree_rotate(tree, grand_parent, right);
++        break;
++    }
++
++    assert(rbtree_node_is_black(tree->root));
++}
++
++void
++rbtree_remove(struct rbtree *tree, struct rbtree_node *node)
++{
++    struct rbtree_node *child, *parent, *brother;
++    int color, left, right;
++
++    if (node->children[RBTREE_LEFT] == NULL)
++        child = node->children[RBTREE_RIGHT];
++    else if (node->children[RBTREE_RIGHT] == NULL)
++        child = node->children[RBTREE_LEFT];
++    else {
++        struct rbtree_node *successor;
++
++        /*
++         * Two-children case: replace the node with its successor.
++         */
++
++        successor = node->children[RBTREE_RIGHT];
++
++        while (successor->children[RBTREE_LEFT] != NULL)
++            successor = successor->children[RBTREE_LEFT];
++
++        color = rbtree_node_color(successor);
++        child = successor->children[RBTREE_RIGHT];
++        parent = rbtree_node_parent(node);
++
++        if (unlikely(parent == NULL))
++            tree->root = successor;
++        else
++            parent->children[rbtree_node_index(node, parent)] = successor;
++
++        parent = rbtree_node_parent(successor);
++
++        /*
++         * Set parent directly to keep the original color.
++         */
++        successor->parent = node->parent;
++        successor->children[RBTREE_LEFT] = node->children[RBTREE_LEFT];
++        rbtree_node_set_parent(successor->children[RBTREE_LEFT], successor);
++
++        if (node == parent)
++            parent = successor;
++        else {
++            successor->children[RBTREE_RIGHT] = node->children[RBTREE_RIGHT];
++            rbtree_node_set_parent(successor->children[RBTREE_RIGHT],
++                                   successor);
++            parent->children[RBTREE_LEFT] = child;
++
++            if (child != NULL)
++                rbtree_node_set_parent(child, parent);
++        }
++
++        goto update_color;
++    }
++
++    /*
++     * Node has at most one child.
++     */
++
++    color = rbtree_node_color(node);
++    parent = rbtree_node_parent(node);
++
++    if (child != NULL)
++        rbtree_node_set_parent(child, parent);
++
++    if (unlikely(parent == NULL))
++        tree->root = child;
++    else
++        parent->children[rbtree_node_index(node, parent)] = child;
++
++    /*
++     * The node has been removed, update the colors. The child pointer can
++     * be NULL, in which case it is considered a black leaf.
++     */
++update_color:
++    if (color == RBTREE_COLOR_RED)
++        return;
++
++    for (;;) {
++        if ((child != NULL) && rbtree_node_is_red(child)) {
++            rbtree_node_set_black(child);
++            break;
++        }
++
++        if (parent == NULL)
++            break;
++
++        left = rbtree_node_index(child, parent);
++        right = 1 - left;
++
++        brother = parent->children[right];
++
++        /*
++         * Brother is red. Recolor and rotate left at parent so that brother
++         * becomes black.
++         */
++        if (rbtree_node_is_red(brother)) {
++            rbtree_node_set_black(brother);
++            rbtree_node_set_red(parent);
++            rbtree_rotate(tree, parent, left);
++            brother = parent->children[right];
++        }
++
++        /*
++         * Brother has no red child. Recolor and repeat at parent.
++         */
++        if (((brother->children[RBTREE_LEFT] == NULL)
++             || rbtree_node_is_black(brother->children[RBTREE_LEFT]))
++            && ((brother->children[RBTREE_RIGHT] == NULL)
++                || rbtree_node_is_black(brother->children[RBTREE_RIGHT]))) {
++            rbtree_node_set_red(brother);
++            child = parent;
++            parent = rbtree_node_parent(child);
++            continue;
++        }
++
++        /*
++         * Brother's right child is black. Recolor and rotate right at brother.
++         */
++        if ((brother->children[right] == NULL)
++            || rbtree_node_is_black(brother->children[right])) {
++            rbtree_node_set_black(brother->children[left]);
++            rbtree_node_set_red(brother);
++            rbtree_rotate(tree, brother, right);
++            brother = parent->children[right];
++        }
++
++        /*
++         * Brother's left child is black. Exchange parent and brother colors
++         * (we already know brother is black), set brother's right child black,
++         * rotate left at parent and leave.
++         */
++        rbtree_node_set_color(brother, rbtree_node_color(parent));
++        rbtree_node_set_black(parent);
++        rbtree_node_set_black(brother->children[right]);
++        rbtree_rotate(tree, parent, left);
++        break;
++    }
++
++    assert((tree->root == NULL) || rbtree_node_is_black(tree->root));
++}
++
++struct rbtree_node *
++rbtree_nearest(struct rbtree_node *parent, int index, int direction)
++{
++    assert(rbtree_check_index(direction));
++
++    if (parent == NULL)
++        return NULL;
++
++    assert(rbtree_check_index(index));
++
++    if (index != direction)
++        return parent;
++
++    return rbtree_walk(parent, direction);
++}
++
++struct rbtree_node *
++rbtree_firstlast(const struct rbtree *tree, int direction)
++{
++    struct rbtree_node *prev, *cur;
++
++    assert(rbtree_check_index(direction));
++
++    prev = NULL;
++
++    for (cur = tree->root; cur != NULL; cur = cur->children[direction])
++        prev = cur;
++
++    return prev;
++}
++
++struct rbtree_node *
++rbtree_walk(struct rbtree_node *node, int direction)
++{
++    int left, right;
++
++    assert(rbtree_check_index(direction));
++
++    left = direction;
++    right = 1 - left;
++
++    if (node == NULL)
++        return NULL;
++
++    if (node->children[left] != NULL) {
++        node = node->children[left];
++
++        while (node->children[right] != NULL)
++            node = node->children[right];
++    } else {
++        struct rbtree_node *parent;
++        int index;
++
++        for (;;) {
++            parent = rbtree_node_parent(node);
++
++            if (parent == NULL)
++                return NULL;
++
++            index = rbtree_node_index(node, parent);
++            node = parent;
++
++            if (index == right)
++                break;
++        }
++    }
++
++    return node;
++}
++
++struct rbtree_node *
++rbtree_postwalk_deepest(const struct rbtree *tree)
++{
++    struct rbtree_node *node;
++
++    node = tree->root;
++
++    if (node == NULL)
++        return NULL;
++
++    return rbtree_node_find_deepest(node);
++}
++
++struct rbtree_node *
++rbtree_postwalk_unlink(struct rbtree_node *node)
++{
++    struct rbtree_node *parent;
++    int index;
++
++    if (node == NULL)
++        return NULL;
++
++    assert(node->children[RBTREE_LEFT] == NULL);
++    assert(node->children[RBTREE_RIGHT] == NULL);
++
++    parent = rbtree_node_parent(node);
++
++    if (parent == NULL)
++        return NULL;
++
++    index = rbtree_node_index(node, parent);
++    parent->children[index] = NULL;
++    node = parent->children[RBTREE_RIGHT];
++
++    if (node == NULL)
++        return parent;
++
++    return rbtree_node_find_deepest(node);
++}
+diff --git a/librbtree/rbtree.h b/librbtree/rbtree.h
+new file mode 100644
+index 0000000..cbb519e
+--- /dev/null
++++ b/librbtree/rbtree.h
+@@ -0,0 +1,310 @@
++/*
++ * Copyright (c) 2010, 2011, 2012 Richard Braun.
++ * All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ *
++ *
++ * Red-black tree.
++ */
++
++#ifndef _RBTREE_H
++#define _RBTREE_H
++
++#include <assert.h>
++#include <stddef.h>
++
++#include "macros.h"
++
++/*
++ * Indexes of the left and right nodes in the children array of a node.
++ */
++#define RBTREE_LEFT     0
++#define RBTREE_RIGHT    1
++
++/*
++ * Red-black node.
++ */
++struct rbtree_node;
++
++/*
++ * Red-black tree.
++ */
++struct rbtree;
++
++/*
++ * Static tree initializer.
++ */
++#define RBTREE_INITIALIZER { NULL }
++
++#include "rbtree_i.h"
++
++/*
++ * Initialize a tree.
++ */
++static inline void
++rbtree_init(struct rbtree *tree)
++{
++    tree->root = NULL;
++}
++
++/*
++ * Initialize a node.
++ *
++ * A node is in no tree when its parent points to itself.
++ */
++static inline void
++rbtree_node_init(struct rbtree_node *node)
++{
++    assert(rbtree_node_check_alignment(node));
++
++    node->parent = (unsigned long)node | RBTREE_COLOR_RED;
++    node->children[RBTREE_LEFT] = NULL;
++    node->children[RBTREE_RIGHT] = NULL;
++}
++
++/*
++ * Return true if node is in no tree.
++ */
++static inline int
++rbtree_node_unlinked(const struct rbtree_node *node)
++{
++    return rbtree_node_parent(node) == node;
++}
++
++/*
++ * Macro that evaluates to the address of the structure containing the
++ * given node based on the given type and member.
++ */
++#define rbtree_entry(node, type, member) structof(node, type, member)
++
++/*
++ * Return true if tree is empty.
++ */
++static inline int
++rbtree_empty(const struct rbtree *tree)
++{
++    return tree->root == NULL;
++}
++
++/*
++ * Look up a node in a tree.
++ *
++ * Note that implementing the lookup algorithm as a macro gives two benefits:
++ * First, it avoids the overhead of a callback function. Next, the type of the
++ * cmp_fn parameter isn't rigid. The only guarantee offered by this
++ * implementation is that the key parameter is the first parameter given to
++ * cmp_fn. This way, users can pass only the value they need for comparison
++ * instead of e.g. allocating a full structure on the stack.
++ *
++ * See rbtree_insert().
++ */
++#define rbtree_lookup(tree, key, cmp_fn)                \
++MACRO_BEGIN                                             \
++    struct rbtree_node *___cur;                         \
++    int ___diff;                                        \
++                                                        \
++    ___cur = (tree)->root;                              \
++                                                        \
++    while (___cur != NULL) {                            \
++        ___diff = cmp_fn(key, ___cur);                  \
++                                                        \
++        if (___diff == 0)                               \
++            break;                                      \
++                                                        \
++        ___cur = ___cur->children[rbtree_d2i(___diff)]; \
++    }                                                   \
++                                                        \
++    ___cur;                                             \
++MACRO_END
++
++/*
++ * Look up a node or one of its nearest nodes in a tree.
++ *
++ * This macro essentially acts as rbtree_lookup() but if no entry matched
++ * the key, an additional step is performed to obtain the next or previous
++ * node, depending on the direction (left or right).
++ *
++ * The constraints that apply to the key parameter are the same as for
++ * rbtree_lookup().
++ */
++#define rbtree_lookup_nearest(tree, key, cmp_fn, dir)       \
++MACRO_BEGIN                                                 \
++    struct rbtree_node *___cur, *___prev;                   \
++    int ___diff, ___index;                                  \
++                                                            \
++    ___prev = NULL;                                         \
++    ___index = -1;                                          \
++    ___cur = (tree)->root;                                  \
++                                                            \
++    while (___cur != NULL) {                                \
++        ___diff = cmp_fn(key, ___cur);                      \
++                                                            \
++        if (___diff == 0)                                   \
++            break;                                          \
++                                                            \
++        ___prev = ___cur;                                   \
++        ___index = rbtree_d2i(___diff);                     \
++        ___cur = ___cur->children[___index];                \
++    }                                                       \
++                                                            \
++    if (___cur == NULL)                                     \
++        ___cur = rbtree_nearest(___prev, ___index, dir);    \
++                                                            \
++    ___cur;                                                 \
++MACRO_END
++
++/*
++ * Insert a node in a tree.
++ *
++ * This macro performs a standard lookup to obtain the insertion point of
++ * the given node in the tree (it is assumed that the inserted node never
++ * compares equal to any other entry in the tree) and links the node. It
++ * then checks red-black rules violations, and rebalances the tree if
++ * necessary.
++ *
++ * Unlike rbtree_lookup(), the cmp_fn parameter must compare two complete
++ * entries, so it is suggested to use two different comparison inline
++ * functions, such as myobj_cmp_lookup() and myobj_cmp_insert(). There is no
++ * guarantee about the order of the nodes given to the comparison function.
++ *
++ * See rbtree_lookup().
++ */
++#define rbtree_insert(tree, node, cmp_fn)                   \
++MACRO_BEGIN                                                 \
++    struct rbtree_node *___cur, *___prev;                   \
++    int ___diff, ___index;                                  \
++                                                            \
++    ___prev = NULL;                                         \
++    ___index = -1;                                          \
++    ___cur = (tree)->root;                                  \
++                                                            \
++    while (___cur != NULL) {                                \
++        ___diff = cmp_fn(node, ___cur);                     \
++        assert(___diff != 0);                               \
++        ___prev = ___cur;                                   \
++        ___index = rbtree_d2i(___diff);                     \
++        ___cur = ___cur->children[___index];                \
++    }                                                       \
++                                                            \
++    rbtree_insert_rebalance(tree, ___prev, ___index, node); \
++MACRO_END
++
++/*
++ * Look up a node/slot pair in a tree.
++ *
++ * This macro essentially acts as rbtree_lookup() but in addition to a node,
++ * it also returns a slot, which identifies an insertion point in the tree.
++ * If the returned node is NULL, the slot can be used by rbtree_insert_slot()
++ * to insert without the overhead of an additional lookup. The slot is a
++ * simple unsigned long integer.
++ *
++ * The constraints that apply to the key parameter are the same as for
++ * rbtree_lookup().
++ */
++#define rbtree_lookup_slot(tree, key, cmp_fn, slot) \
++MACRO_BEGIN                                         \
++    struct rbtree_node *___cur, *___prev;           \
++    int ___diff, ___index;                          \
++                                                    \
++    ___prev = NULL;                                 \
++    ___index = 0;                                   \
++    ___cur = (tree)->root;                          \
++                                                    \
++    while (___cur != NULL) {                        \
++        ___diff = cmp_fn(key, ___cur);              \
++                                                    \
++        if (___diff == 0)                           \
++            break;                                  \
++                                                    \
++        ___prev = ___cur;                           \
++        ___index = rbtree_d2i(___diff);             \
++        ___cur = ___cur->children[___index];        \
++    }                                               \
++                                                    \
++    (slot) = rbtree_slot(___prev, ___index);        \
++    ___cur;                                         \
++MACRO_END
++
++/*
++ * Insert a node at an insertion point in a tree.
++ *
++ * This macro essentially acts as rbtree_insert() except that it doesn't
++ * obtain the insertion point with a standard lookup. The insertion point
++ * is obtained by calling rbtree_lookup_slot(). In addition, the new node
++ * must not compare equal to an existing node in the tree (i.e. the slot
++ * must denote a NULL node).
++ */
++static inline void
++rbtree_insert_slot(struct rbtree *tree, unsigned long slot,
++                   struct rbtree_node *node)
++{
++    struct rbtree_node *parent;
++    int index;
++
++    parent = rbtree_slot_parent(slot);
++    index = rbtree_slot_index(slot);
++    rbtree_insert_rebalance(tree, parent, index, node);
++}
++
++/*
++ * Remove a node from a tree.
++ *
++ * After completion, the node is stale.
++ */
++void rbtree_remove(struct rbtree *tree, struct rbtree_node *node);
++
++/*
++ * Return the first node of a tree.
++ */
++#define rbtree_first(tree) rbtree_firstlast(tree, RBTREE_LEFT)
++
++/*
++ * Return the last node of a tree.
++ */
++#define rbtree_last(tree) rbtree_firstlast(tree, RBTREE_RIGHT)
++
++/*
++ * Return the node previous to the given node.
++ */
++#define rbtree_prev(node) rbtree_walk(node, RBTREE_LEFT)
++
++/*
++ * Return the node next to the given node.
++ */
++#define rbtree_next(node) rbtree_walk(node, RBTREE_RIGHT)
++
++/*
++ * Forge a loop to process all nodes of a tree, removing them when visited.
++ *
++ * This macro can only be used to destroy a tree, so that the resources used
++ * by the entries can be released by the user. It basically removes all nodes
++ * without doing any color checking.
++ *
++ * After completion, all nodes and the tree root member are stale.
++ */
++#define rbtree_for_each_remove(tree, node, tmp)         \
++for (node = rbtree_postwalk_deepest(tree),              \
++     tmp = rbtree_postwalk_unlink(node);                \
++     node != NULL;                                      \
++     node = tmp, tmp = rbtree_postwalk_unlink(node))    \
++
++#endif /* _RBTREE_H */
+diff --git a/librbtree/rbtree_i.h b/librbtree/rbtree_i.h
+new file mode 100644
+index 0000000..eb1619f
+--- /dev/null
++++ b/librbtree/rbtree_i.h
+@@ -0,0 +1,196 @@
++/*
++ * Copyright (c) 2010, 2011, 2012 Richard Braun.
++ * All rights reserved.
++ *
++ * Redistribution and use in source and binary forms, with or without
++ * modification, are permitted provided that the following conditions
++ * are met:
++ * 1. Redistributions of source code must retain the above copyright
++ *    notice, this list of conditions and the following disclaimer.
++ * 2. Redistributions in binary form must reproduce the above copyright
++ *    notice, this list of conditions and the following disclaimer in the
++ *    documentation and/or other materials provided with the distribution.
++ *
++ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
++ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
++ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
++ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
++ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
++ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
++ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
++ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
++ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
++ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
++ */
++
++#ifndef _RBTREE_I_H
++#define _RBTREE_I_H
++
++#include <assert.h>
++#include <stddef.h>
++
++#include "macros.h"
++
++/*
++ * Red-black node structure.
++ *
++ * To reduce the number of branches and the instruction cache footprint,
++ * the left and right child pointers are stored in an array, and the symmetry
++ * of most tree operations is exploited by using left/right variables when
++ * referring to children.
++ *
++ * In addition, this implementation assumes that all nodes are 4-byte aligned,
++ * so that the least significant bit of the parent member can be used to store
++ * the color of the node. This is true for all modern 32 and 64 bits
++ * architectures, as long as the nodes aren't embedded in structures with
++ * special alignment constraints such as member packing.
++ */
++struct rbtree_node {
++    unsigned long parent;
++    struct rbtree_node *children[2];
++};
++
++/*
++ * Red-black tree structure.
++ */
++struct rbtree {
++    struct rbtree_node *root;
++};
++
++/*
++ * Masks applied on the parent member of a node to obtain either the
++ * color or the parent address.
++ */
++#define RBTREE_COLOR_MASK   0x1UL
++#define RBTREE_PARENT_MASK  (~0x3UL)
++
++/*
++ * Node colors.
++ */
++#define RBTREE_COLOR_RED    0
++#define RBTREE_COLOR_BLACK  1
++
++/*
++ * Masks applied on slots to obtain either the child index or the parent
++ * address.
++ */
++#define RBTREE_SLOT_INDEX_MASK  0x1UL
++#define RBTREE_SLOT_PARENT_MASK (~RBTREE_SLOT_INDEX_MASK)
++
++/*
++ * Return true if the given index is a valid child index.
++ */
++static inline int
++rbtree_check_index(int index)
++{
++    return index == (index & 1);
++}
++
++/*
++ * Convert the result of a comparison into an index in the children array
++ * (0 or 1).
++ *
++ * This function is mostly used when looking up a node.
++ */
++static inline int
++rbtree_d2i(int diff)
++{
++    return !(diff <= 0);
++}
++
++/*
++ * Return true if the given pointer is suitably aligned.
++ */
++static inline int
++rbtree_node_check_alignment(const struct rbtree_node *node)
++{
++    return ((unsigned long)node & (~RBTREE_PARENT_MASK)) == 0;
++}
++
++/*
++ * Return the parent of a node.
++ */
++static inline struct rbtree_node *
++rbtree_node_parent(const struct rbtree_node *node)
++{
++    return (struct rbtree_node *)(node->parent & RBTREE_PARENT_MASK);
++}
++
++/*
++ * Translate an insertion point into a slot.
++ */
++static inline unsigned long
++rbtree_slot(struct rbtree_node *parent, int index)
++{
++    assert(rbtree_node_check_alignment(parent));
++    assert(rbtree_check_index(index));
++    return (unsigned long)parent | index;
++}
++
++/*
++ * Extract the parent address from a slot.
++ */
++static inline struct rbtree_node *
++rbtree_slot_parent(unsigned long slot)
++{
++    return (struct rbtree_node *)(slot & RBTREE_SLOT_PARENT_MASK);
++}
++
++/*
++ * Extract the index from a slot.
++ */
++static inline int
++rbtree_slot_index(unsigned long slot)
++{
++    return slot & RBTREE_SLOT_INDEX_MASK;
++}
++
++/*
++ * Insert a node in a tree, rebalancing it if necessary.
++ *
++ * The index parameter is the index in the children array of the parent where
++ * the new node is to be inserted. It is ignored if the parent is NULL.
++ *
++ * This function is intended to be used by the rbtree_insert() macro only.
++ */
++void rbtree_insert_rebalance(struct rbtree *tree, struct rbtree_node *parent,
++                             int index, struct rbtree_node *node);
++
++/*
++ * Return the previous or next node relative to a location in a tree.
++ *
++ * The parent and index parameters define the location, which can be empty.
++ * The direction parameter is either RBTREE_LEFT (to obtain the previous
++ * node) or RBTREE_RIGHT (to obtain the next one).
++ */
++struct rbtree_node * rbtree_nearest(struct rbtree_node *parent, int index,
++                                    int direction);
++
++/*
++ * Return the first or last node of a tree.
++ *
++ * The direction parameter is either RBTREE_LEFT (to obtain the first node)
++ * or RBTREE_RIGHT (to obtain the last one).
++ */
++struct rbtree_node * rbtree_firstlast(const struct rbtree *tree, int direction);
++
++/*
++ * Return the node next to, or previous to the given node.
++ *
++ * The direction parameter is either RBTREE_LEFT (to obtain the previous node)
++ * or RBTREE_RIGHT (to obtain the next one).
++ */
++struct rbtree_node * rbtree_walk(struct rbtree_node *node, int direction);
++
++/*
++ * Return the left-most deepest node of a tree, which is the starting point of
++ * the postorder traversal performed by rbtree_for_each_remove().
++ */
++struct rbtree_node * rbtree_postwalk_deepest(const struct rbtree *tree);
++
++/*
++ * Unlink a node from its tree and return the next (right) node in postorder.
++ */
++struct rbtree_node * rbtree_postwalk_unlink(struct rbtree_node *node);
++
++#endif /* _RBTREE_I_H */
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/0016-ext2fs-use-librbtree-for-the-nodehash.patch b/debian/patches/0016-ext2fs-use-librbtree-for-the-nodehash.patch
new file mode 100644
index 00000000..0ce43428
--- /dev/null
+++ b/debian/patches/0016-ext2fs-use-librbtree-for-the-nodehash.patch
@@ -0,0 +1,314 @@
+From 8ee1d0fc5e92489a6e50c78f3ac1e1dd66206366 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Wed, 14 May 2014 15:30:19 +0200
+Subject: [PATCH 16/16] ext2fs: use librbtree for the nodehash
+
+Previously, a lookup of a node through nodehash took O(N / INOHSZ).
+With INOHSZ being a constant (512) this is linear in N.  Use a
+red-black tree instead, which guarantees a lookup performance in
+O(log N) time.
+
+* ext2fs/inode.c (INOHSZ, INOHASH): Remove.
+(nodehash): Use a red-black tree.
+(node_cmp_lookup, node_cmp_insert, node_get_np): New functions.
+(inode_init): Remove.
+(diskfs_cached_lookup): Adjust accordingly.
+(ifind, diskfs_try_dropping_softrefs, diskfs_node_iterate): Likewise.
+* ext2fs/ext2fs.h (struct disknode): Remove list pointers, add
+red-black tree node.  Because we store disknode objects in the tree,
+we also need a pointer to the node object, and the cache_id for
+efficient operations on the rb tree.
+* ext2fs/ext2fs.c (main): Drop inode_init.
+---
+ ext2fs/Makefile |   2 +-
+ ext2fs/ext2fs.c |   2 -
+ ext2fs/ext2fs.h |   7 ++--
+ ext2fs/inode.c  | 124 +++++++++++++++++++++++++++++---------------------------
+ 4 files changed, 70 insertions(+), 65 deletions(-)
+
+diff --git a/ext2fs/Makefile b/ext2fs/Makefile
+index 8d2e68c..b075dc0 100644
+--- a/ext2fs/Makefile
++++ b/ext2fs/Makefile
+@@ -23,7 +23,7 @@ target = ext2fs
+ SRCS = balloc.c dir.c ext2fs.c getblk.c hyper.c ialloc.c \
+        inode.c pager.c pokel.c truncate.c storeinfo.c msg.c xinl.c
+ OBJS = $(SRCS:.c=.o)
+-HURDLIBS = diskfs pager iohelp fshelp store ports ihash shouldbeinlibc
++HURDLIBS = diskfs pager iohelp fshelp store ports ihash rbtree shouldbeinlibc
+ OTHERLIBS = -lpthread $(and $(HAVE_LIBBZ2),-lbz2) $(and $(HAVE_LIBZ),-lz)
+ 
+ include ../Makeconf
+diff --git a/ext2fs/ext2fs.c b/ext2fs/ext2fs.c
+index 128b6ed..0409dfb 100644
+--- a/ext2fs/ext2fs.c
++++ b/ext2fs/ext2fs.c
+@@ -185,8 +185,6 @@ main (int argc, char **argv)
+ 
+   map_hypermetadata ();
+ 
+-  inode_init ();
+-
+   /* Set diskfs_root_node to the root inode. */
+   err = diskfs_cached_lookup (EXT2_ROOT_INO, &diskfs_root_node);
+   if (err)
+diff --git a/ext2fs/ext2fs.h b/ext2fs/ext2fs.h
+index 3422af2..3505bb7 100644
+--- a/ext2fs/ext2fs.h
++++ b/ext2fs/ext2fs.h
+@@ -26,6 +26,7 @@
+ #include <hurd/store.h>
+ #include <hurd/diskfs.h>
+ #include <hurd/ihash.h>
++#include <hurd/rbtree.h>
+ #include <assert.h>
+ #include <pthread.h>
+ #include <sys/mman.h>
+@@ -155,13 +156,13 @@ clear_bit (unsigned num, char *bitmap)
+ /* ext2fs specific per-file data.  */
+ struct disknode
+ {
++  /* Red-black-tree node for the node cache.  */
++  struct rbtree_node tree_node;
++
+   /* For a directory, this array holds the number of directory entries in
+      each DIRBLKSIZE piece of the directory. */
+   int *dirents;
+ 
+-  /* Links on hash list. */
+-  struct node *hnext, **hprevp;
+-
+   /* Lock to lock while fiddling with this inode's block allocation info.  */
+   pthread_rwlock_t alloc_lock;
+ 
+diff --git a/ext2fs/inode.c b/ext2fs/inode.c
+index 7ec343f..0142bf6 100644
+--- a/ext2fs/inode.c
++++ b/ext2fs/inode.c
+@@ -20,6 +20,7 @@
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 
+ #include "ext2fs.h"
++#include <stddef.h>
+ #include <string.h>
+ #include <unistd.h>
+ #include <stdio.h>
+@@ -39,13 +40,6 @@
+ #define UF_IMMUTABLE 0
+ #endif
+ 
+-#define	INOHSZ	512
+-#if	((INOHSZ&(INOHSZ-1)) == 0)
+-#define	INOHASH(ino)	((ino)&(INOHSZ-1))
+-#else
+-#define	INOHASH(ino)	(((unsigned)(ino))%INOHSZ)
+-#endif
+-
+ /* The nodehash is a cache of nodes.
+ 
+    Access to nodehash and nodehash_nr_items is protected by
+@@ -55,23 +49,45 @@
+    asked to give up that light reference, we reacquire our lock
+    momentarily to check whether someone else reacquired a reference
+    through the nodehash.  */
+-static struct node *nodehash[INOHSZ];
++static struct rbtree nodehash = RBTREE_INITIALIZER;
+ static size_t nodehash_nr_items;
+ static pthread_mutex_t nodehash_lock = PTHREAD_MUTEX_INITIALIZER;
+ 
+-static error_t read_node (struct node *np);
++static inline struct node *
++node_get_np (const struct rbtree_node *node)
++{
++  struct disknode *dn;
+ 
+-pthread_spinlock_t generation_lock = PTHREAD_SPINLOCK_INITIALIZER;
++  dn = rbtree_entry (node, struct disknode, tree_node);
+ 
+-/* Initialize the inode hash table. */
+-void
+-inode_init ()
++  return diskfs_disknode_node (dn);
++}
++
++static inline int
++node_cmp_lookup (const ino_t inum,
++		 const struct rbtree_node *node)
+ {
+-  int n;
+-  for (n = 0; n < INOHSZ; n++)
+-    nodehash[n] = 0;
++  struct node *np = node_get_np (node);
++
++  if (inum == np->cache_id)
++    return 0;
++  else if (inum < np->cache_id)
++    return -1;
++  else
++    return 1;
+ }
+ 
++static inline int
++node_cmp_insert (const struct rbtree_node *a,
++		 const struct rbtree_node *b)
++{
++  return node_cmp_lookup (node_get_np (a)->cache_id, b);
++}
++
++static error_t read_node (struct node *np);
++
++pthread_spinlock_t generation_lock = PTHREAD_SPINLOCK_INITIALIZER;
++
+ /* Fetch inode INUM, set *NPP to the node structure;
+    gain one user reference and lock the node.  */
+ error_t
+@@ -79,47 +95,42 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+ {
+   error_t err;
+   struct node *np;
++  struct rbtree_node *node;
++  unsigned long slot;
+   struct disknode *dn;
+ 
+   pthread_mutex_lock (&nodehash_lock);
+-  for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+-    if (np->cache_id == inum)
+-      {
+-	diskfs_nref (np);
+-	pthread_mutex_unlock (&nodehash_lock);
+-	pthread_mutex_lock (&np->lock);
+-	*npp = np;
+-	return 0;
+-      }
+-
+-  /* Format specific data for the new node.  */
+-  dn = malloc (sizeof (struct disknode));
+-  if (! dn)
++  node = rbtree_lookup_slot (&nodehash, inum, node_cmp_lookup, slot);
++  if (node != NULL)
++    {
++      np = node_get_np (node);
++      diskfs_nref (np);
++      pthread_mutex_unlock (&nodehash_lock);
++      pthread_mutex_lock (&np->lock);
++      *npp = np;
++      return 0;
++    }
++
++  /* Create the new node.  */
++  np = diskfs_make_node_alloc (sizeof *dn);
++  if (np == NULL)
+     {
+       pthread_mutex_unlock (&nodehash_lock);
+       return ENOMEM;
+     }
++  np->cache_id = inum;
++  dn = diskfs_node_disknode (np);
+   dn->dirents = 0;
+   dn->dir_idx = 0;
+   dn->pager = 0;
+   pthread_rwlock_init (&dn->alloc_lock, NULL);
+   pokel_init (&dn->indir_pokel, diskfs_disk_pager, disk_cache);
+-
+-  /* Create the new node.  */
+-  np = diskfs_make_node (dn);
+-  np->cache_id = inum;
+-
+   pthread_mutex_lock (&np->lock);
+ 
+   /* Put NP in NODEHASH.  */
+-  dn->hnext = nodehash[INOHASH(inum)];
+-  if (dn->hnext)
+-    dn->hnext->dn->hprevp = &dn->hnext;
+-  dn->hprevp = &nodehash[INOHASH(inum)];
+-  nodehash[INOHASH(inum)] = np;
+   diskfs_nref_light (np);
++  rbtree_insert_slot (&nodehash, slot, &dn->tree_node);
+   nodehash_nr_items += 1;
+-
+   pthread_mutex_unlock (&nodehash_lock);
+ 
+   /* Get the contents of NP off disk.  */
+@@ -149,16 +160,14 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+ struct node *
+ ifind (ino_t inum)
+ {
+-  struct node *np;
++  struct rbtree_node *node;
+ 
+   pthread_mutex_lock (&nodehash_lock);
+-  for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
++  node = rbtree_lookup (&nodehash, inum, node_cmp_lookup);
++  if (node != NULL)
+     {
+-      if (np->cache_id != inum)
+-	continue;
+-
+       pthread_mutex_unlock (&nodehash_lock);
+-      return np;
++      return node_get_np (node);
+     }
+   assert (0);
+ }
+@@ -176,7 +185,6 @@ diskfs_node_norefs (struct node *np)
+   pokel_inherit (&global_pokel, &np->dn->indir_pokel);
+   pokel_finalize (&np->dn->indir_pokel);
+ 
+-  free (np->dn);
+   free (np);
+ }
+ 
+@@ -186,7 +194,7 @@ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
+   pthread_mutex_lock (&nodehash_lock);
+-  if (np->dn->hnext != NULL)
++  if (np->cache_id != 0)
+     {
+       /* Check if someone reacquired a reference through the
+          nodehash.  */
+@@ -200,11 +208,9 @@ diskfs_try_dropping_softrefs (struct node *np)
+           return;
+         }
+ 
+-      *np->dn->hprevp = np->dn->hnext;
+-      if (np->dn->hnext)
+-        np->dn->hnext->dn->hprevp = np->dn->hprevp;
+-      np->dn->hnext = NULL;
++      rbtree_remove (&nodehash, &(diskfs_node_disknode (np))->tree_node);
+       nodehash_nr_items -= 1;
++      np->cache_id = 0;
+       diskfs_nrele_light (np);
+     }
+   pthread_mutex_unlock (&nodehash_lock);
+@@ -581,7 +587,7 @@ error_t
+ diskfs_node_iterate (error_t (*fun)(struct node *))
+ {
+   error_t err = 0;
+-  int n;
++  struct rbtree_node *n;
+   size_t num_nodes;
+   struct node *node, **node_list, **p;
+ 
+@@ -605,12 +611,12 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+     }
+ 
+   p = node_list;
+-  for (n = 0; n < INOHSZ; n++)
+-    for (node = nodehash[n]; node; node = node->dn->hnext)
+-      {
+-	*p++ = node;
+-	diskfs_nref (node);
+-      }
++  for (n = rbtree_first (&nodehash); n; n = rbtree_next (n))
++    {
++      node = node_get_np (n);
++      *p++ = node;
++      diskfs_nref (node);
++    }
+ 
+   pthread_mutex_unlock (&nodehash_lock);
+ 
+-- 
+2.0.0.rc2
+
diff --git a/debian/patches/series b/debian/patches/series
index 6f1da5d7..eb7a052a 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -42,3 +42,19 @@ mach-defpager-protected-payload.patch
 
 #0010-libihash-make-the-locp-offset-mechanism-more-flexibl.patch
 #0011-trans-fakeroot-use-the-indirection-mechanism-for-loc.patch
+0001-libdiskfs-add-diskfs_make_node_alloc-to-allocate-fat.patch
+0002-libnetfs-add-netfs_make_node_alloc-to-allocate-fat-n.patch
+0003-trans-fakeroot-use-fat-nodes-to-simplify-the-node-ca.patch
+0004-trans-fakeroot-use-netfs_node_netnode-instead-of-np-.patch
+0005-include-add-lock-less-reference-counting-primitives.patch
+0006-libdiskfs-lock-less-reference-counting-for-peropen-o.patch
+0007-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch
+0008-libports-use-a-single-hash-table.patch
+0009-libports-lock-less-reference-counting-for-port_info-.patch
+0010-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
+0011-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
+0012-isofs-use-a-seperate-lock-to-protect-node_cache.patch
+0013-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
+0014-libdiskfs-lock-less-reference-counting-of-nodes.patch
+0015-librbtree-add-a-red-black-tree-implementation.patch
+0016-ext2fs-use-librbtree-for-the-nodehash.patch