add patch series

14 files changed, 3134 insertions, 0 deletions

diff --git a/debian/patches/0001-include-add-lock-less-reference-counting-primitives.patch b/debian/patches/0001-include-add-lock-less-reference-counting-primitives.patch
new file mode 100644
index 00000000..4a194b54
--- /dev/null
+++ b/debian/patches/0001-include-add-lock-less-reference-counting-primitives.patch
@@ -0,0 +1,213 @@
+From 6d56f1b470b40176e0386012648333ba9b2aa95b 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 01/13] include: add lock-less reference counting primitives
+
+* include/refcount.h: New file.
+---
+ include/refcount.h | 193 +++++++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 193 insertions(+)
+ create mode 100644 include/refcount.h
+
+diff --git a/include/refcount.h b/include/refcount.h
+new file mode 100644
+index 0000000..0816220
+--- /dev/null
++++ b/include/refcount.h
+@@ -0,0 +1,193 @@
++/* 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 <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);
++  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);
++  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 {
++  uint32_t hard;
++  uint32_t weak;
++};
++
++/* 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);
++  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);
++  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);
++  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);
++  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.rc0
+
diff --git a/debian/patches/0002-libdiskfs-lock-less-reference-counting-for-peropen-o.patch b/debian/patches/0002-libdiskfs-lock-less-reference-counting-for-peropen-o.patch
new file mode 100644
index 00000000..3240708d
--- /dev/null
+++ b/debian/patches/0002-libdiskfs-lock-less-reference-counting-for-peropen-o.patch
@@ -0,0 +1,143 @@
+From 3f5e255e1c33f48ec2d8594b26a0c84b9cd09a70 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 02/13] 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 8151ddc..ae1a150 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;
+@@ -792,12 +793,12 @@ 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.rc0
+
diff --git a/debian/patches/0003-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch b/debian/patches/0003-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch
new file mode 100644
index 00000000..df540db5
--- /dev/null
+++ b/debian/patches/0003-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch
@@ -0,0 +1,172 @@
+From 8d6d02e37766e645440d9d5d91d5f48b161482a1 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 03/13] 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.rc0
+
diff --git a/debian/patches/0004-libports-use-a-single-hash-table.patch b/debian/patches/0004-libports-use-a-single-hash-table.patch
new file mode 100644
index 00000000..18f4eadd
--- /dev/null
+++ b/debian/patches/0004-libports-use-a-single-hash-table.patch
@@ -0,0 +1,619 @@
+From 3ee3553bf6d464c1f27e795ffb64153154f6e0fe 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 04/13] 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           | 21 +++++++++++++++------
+ libports/claim-right.c              |  6 ++++--
+ libports/class-iterate.c            | 10 +---------
+ libports/complete-deallocate.c      |  8 +++-----
+ libports/create-bucket.c            |  7 -------
+ libports/create-class.c             |  1 -
+ libports/create-internal.c          |  9 +++------
+ libports/destroy-right.c            |  6 +++---
+ libports/import-port.c              |  9 +++------
+ libports/inhibit-all-rpcs.c         | 27 +++++++++++++--------------
+ libports/inhibit-bucket-rpcs.c      |  7 +++++--
+ libports/inhibit-class-rpcs.c       | 27 ++++++++++++++++++---------
+ libports/init.c                     |  7 ++++++-
+ libports/lookup-port.c              | 21 ++++++++-------------
+ libports/ports.h                    | 11 ++++++-----
+ libports/reallocate-from-external.c | 16 ++++++++++------
+ libports/reallocate-port.c          | 10 +++++++---
+ libports/transfer-right.c           | 20 +++++++++++++-------
+ 18 files changed, 118 insertions(+), 105 deletions(-)
+
+diff --git a/libports/bucket-iterate.c b/libports/bucket-iterate.c
+index babc204..d5f590e 100644
+--- a/libports/bucket-iterate.c
++++ b/libports/bucket-iterate.c
+@@ -36,35 +36,44 @@ _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 (_ports_htable.nr_items == 0)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       return 0;
+     }
+ 
+-  nr_items = bucket->htable.nr_items;
++  nr_items = _ports_htable.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 (&_ports_htable, arg)
+     {
+       struct port_info *const pi = arg;
+ 
+-      if (class == 0 || pi->class == class)
++      if ((bucket == NULL || pi->bucket == bucket)
++          && (class == NULL || pi->class == class))
+ 	{
+ 	  pi->refcnt++;
+ 	  p[n] = pi;
+ 	  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.  */
+diff --git a/libports/claim-right.c b/libports/claim-right.c
+index 4851ea3..f453a82 100644
+--- a/libports/claim-right.c
++++ b/libports/claim-right.c
+@@ -34,10 +34,12 @@ ports_claim_right (void *portstruct)
+   if (ret == MACH_PORT_NULL)
+     return ret;
+ 
+-  pthread_mutex_lock (&_ports_lock);
+-  hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++  pthread_mutex_lock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_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..5cfcfc8 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 (NULL, class, fun);
+ }
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 8ce095b..1371d92 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -29,16 +29,14 @@ _ports_complete_deallocate (struct port_info *pi)
+ 
+   if (pi->port_right)
+     {
+-      hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_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..9f6821d 100644
+--- a/libports/create-bucket.c
++++ b/libports/create-bucket.c
+@@ -46,13 +46,6 @@ ports_create_bucket ()
+       return NULL;
+     }
+ 
+-  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..e773dd6 100644
+--- a/libports/create-internal.c
++++ b/libports/create-internal.c
+@@ -81,15 +81,12 @@ _ports_create_port_internal (struct port_class *class,
+       goto loop;
+     }
+ 
+-  err = hurd_ihash_add (&bucket->htable, port, pi);
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, port, pi);
++  pthread_mutex_unlock (&_ports_htable_lock);
+   if (err)
+     goto lose;
+ 
+-  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..6ba7302 100644
+--- a/libports/destroy-right.c
++++ b/libports/destroy-right.c
+@@ -30,12 +30,12 @@ ports_destroy_right (void *portstruct)
+ 
+   if (pi->port_right != MACH_PORT_NULL)
+     {
+-      pthread_mutex_lock (&_ports_lock);
+-      hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_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..d0b2ea4 100644
+--- a/libports/import-port.c
++++ b/libports/import-port.c
+@@ -75,15 +75,12 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket,
+       goto loop;
+     }
+ 
+-  err = hurd_ihash_add (&bucket->htable, port, pi);
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, port, pi);
++  pthread_mutex_unlock (&_ports_htable_lock);
+   if (err)
+     goto lose;
+ 
+-  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..ed3e29d 100644
+--- a/libports/inhibit-bucket-rpcs.c
++++ b/libports/inhibit-bucket-rpcs.c
+@@ -35,10 +35,13 @@ ports_inhibit_bucket_rpcs (struct port_bucket *bucket)
+     {
+       int this_one = 0;
+ 
+-      HURD_IHASH_ITERATE (&bucket->htable, portstruct)
++      pthread_mutex_lock (&_ports_htable_lock);
++      HURD_IHASH_ITERATE (&_ports_htable, portstruct)
+ 	{
+ 	  struct rpc_info *rpc;
+ 	  struct port_info *pi = portstruct;
++	  if (pi->bucket != bucket)
++	    continue;
+ 
+ 	  for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
+ 	    {
+@@ -49,7 +52,7 @@ 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..8fbc7e8 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, hentry));
++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..9c5f14d 100644
+--- a/libports/ports.h
++++ b/libports/ports.h
+@@ -48,7 +48,6 @@ 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 */
+ };
+ typedef struct port_info *port_info_t;
+ 
+@@ -61,11 +60,9 @@ typedef struct port_info *port_info_t;
+ struct port_bucket
+ {
+   mach_port_t portset;
+-  struct hurd_ihash htable;
+   int rpcs;
+   int flags;
+   int count;
+-  struct port_bucket *next;
+ };
+ /* FLAGS above are the following: */
+ #define PORT_BUCKET_INHIBITED	PORTS_INHIBITED
+@@ -78,7 +75,6 @@ struct port_class
+ {
+   int flags;
+   int rpcs;
+-  struct port_info *ports;
+   int count;
+   void (*clean_routine) (void *);
+   void (*dropweak_routine) (void *);
+@@ -402,7 +398,12 @@ 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..bbcf9ba 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -43,8 +43,10 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+ 			    MACH_PORT_RIGHT_RECEIVE, -1);
+   assert_perror (err);
+ 
+-  hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+-  
++  pthread_mutex_lock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->hentry);
++  pthread_mutex_unlock (&_ports_htable_lock);
++
+   if ((pi->flags & PORT_HAS_SENDRIGHTS) && !stat.mps_srights)
+     {
+       dropref = 1;
+@@ -59,11 +61,13 @@ 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);
+-  assert_perror (err);
++
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_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..99c4041 100644
+--- a/libports/reallocate-port.c
++++ b/libports/reallocate-port.c
+@@ -36,7 +36,9 @@ ports_reallocate_port (void *portstruct)
+ 			    MACH_PORT_RIGHT_RECEIVE, -1);
+   assert_perror (err);
+ 
+-  hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++  pthread_mutex_lock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_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 +50,11 @@ ports_reallocate_port (void *portstruct)
+     }
+   pi->cancel_threshold = 0;
+   pi->mscount = 0;
+-  err = hurd_ihash_add (&pi->bucket->htable, pi->port_right, pi);
+-  assert_perror (err);
++  pthread_mutex_lock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_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..5a7653d 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -41,7 +41,9 @@ ports_transfer_right (void *tostruct,
+   port = frompi->port_right;
+   if (port != MACH_PORT_NULL)
+     {
+-      hurd_ihash_locp_remove (&frompi->bucket->htable, frompi->hentry);
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, frompi->hentry);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       frompi->port_right = MACH_PORT_NULL;
+       if (frompi->flags & PORT_HAS_SENDRIGHTS)
+ 	{
+@@ -54,7 +56,9 @@ ports_transfer_right (void *tostruct,
+   /* Destroy the existing right in TOPI. */
+   if (topi->port_right != MACH_PORT_NULL)
+     {
+-      hurd_ihash_locp_remove (&topi->bucket->htable, topi->hentry);
++      pthread_mutex_lock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_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 +78,14 @@ 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)
+     {
+-      err = hurd_ihash_add (&topi->bucket->htable, port, topi);
++      pthread_mutex_lock (&_ports_htable_lock);
++      err = hurd_ihash_add (&_ports_htable, port, topi);
++      pthread_mutex_unlock (&_ports_htable_lock);
+       assert_perror (err);
+       if (topi->bucket != frompi->bucket)
+         {
+@@ -86,9 +94,7 @@ 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.rc0
+
diff --git a/debian/patches/0005-libports-lock-less-reference-counting-for-port_info-.patch b/debian/patches/0005-libports-lock-less-reference-counting-for-port_info-.patch
new file mode 100644
index 00000000..f8bf63df
--- /dev/null
+++ b/debian/patches/0005-libports-lock-less-reference-counting-for-port_info-.patch
@@ -0,0 +1,345 @@
+From 0806cc87d94e50c05fe883a979155d28a34b8d98 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 05/13] 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      | 15 +++++++++++++++
+ 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, 58 insertions(+), 53 deletions(-)
+
+diff --git a/libports/bucket-iterate.c b/libports/bucket-iterate.c
+index d5f590e..2a2b2b6 100644
+--- a/libports/bucket-iterate.c
++++ b/libports/bucket-iterate.c
+@@ -35,7 +35,6 @@ _ports_bucket_class_iterate (struct port_bucket *bucket,
+   size_t i, n, nr_items;
+   error_t err;
+ 
+-  pthread_mutex_lock (&_ports_lock);
+   pthread_mutex_lock (&_ports_htable_lock);
+ 
+   if (_ports_htable.nr_items == 0)
+@@ -60,13 +59,12 @@ _ports_bucket_class_iterate (struct port_bucket *bucket,
+       if ((bucket == NULL || pi->bucket == bucket)
+           && (class == NULL || 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 1371d92..6c9074a 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -29,14 +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->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 e773dd6..9e3824d 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 d0b2ea4..e250b0e 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..dd38f55 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 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 before we release our hard reference.
++     The order is important here to prevent a race.  */
++  if (pi->class->dropweak_routine)
++    refcounts_ref_weak (&pi->refcounts, NULL);
++
++  refcounts_deref (&pi->refcounts, &result);
++
++  if (pi->class->dropweak_routine)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
+-      (*pi->class->dropweak_routine) (pi);
+-      trieddroppingweakrefs = 1;
+-      goto retry;
++      if (result.hard == 0 && result.weak > 1)
++        (*pi->class->dropweak_routine) (pi);
++      refcounts_deref_weak (&pi->refcounts, &result);
+     }
+-  
+-  assert (pi->refcnt);
+ 
+-  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 9c5f14d..116e920 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 bbcf9ba..5ee579d 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -55,7 +55,7 @@ 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 5a7653d..d3ff0f4 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -70,7 +70,7 @@ 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.rc0
+
diff --git a/debian/patches/0006-include-add-refcounts_demote-that-demotes-a-hard-ref.patch b/debian/patches/0006-include-add-refcounts_demote-that-demotes-a-hard-ref.patch
new file mode 100644
index 00000000..2c1fcd3b
--- /dev/null
+++ b/debian/patches/0006-include-add-refcounts_demote-that-demotes-a-hard-ref.patch
@@ -0,0 +1,115 @@
+From a1f4af1716aa9c00358816ab7f82dac2cabdd961 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Tue, 13 May 2014 23:04:40 +0200
+Subject: [PATCH 06/13] include: add refcounts_demote that demotes a hard
+ reference
+
+refcounts_demote atomically demotes a hard reference to a weak one.
+This reduces the number of required atomic operations from three to
+two when a hard reference is dropped and a dropweak routine is
+installed.
+
+* include/refcount.h (refcounts_demote): New function.
+* libports/port-deref.c (ports_port_deref): Use the new function.
+---
+ include/refcount.h    | 39 +++++++++++++++++++++++++++++++++++++++
+ libports/port-deref.c | 18 +++++++++---------
+ 2 files changed, 48 insertions(+), 9 deletions(-)
+
+diff --git a/include/refcount.h b/include/refcount.h
+index 0816220..2aafb9e 100644
+--- a/include/refcount.h
++++ b/include/refcount.h
+@@ -77,8 +77,18 @@ 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.  This way we can implement atomically demoting
++     a hard reference to a weak reference.  See 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
+@@ -127,6 +137,35 @@ refcounts_deref (refcounts_t *ref, struct references *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
++          && r.references.weak != UINT32_MAX);
++  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
+diff --git a/libports/port-deref.c b/libports/port-deref.c
+index dd38f55..b97dd13 100644
+--- a/libports/port-deref.c
++++ b/libports/port-deref.c
+@@ -27,21 +27,21 @@ ports_port_deref (void *portstruct)
+   struct port_info *pi = portstruct;
+   struct references result;
+ 
+-  /* 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 before we release our hard reference.
+-     The order is important here to prevent a race.  */
+-  if (pi->class->dropweak_routine)
+-    refcounts_ref_weak (&pi->refcounts, NULL);
+-
+-  refcounts_deref (&pi->refcounts, &result);
+-
+   if (pi->class->dropweak_routine)
+     {
++      /* 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);
+     }
++  else
++    refcounts_deref (&pi->refcounts, &result);
+ 
+   if (result.hard == 0 && result.weak == 0)
+     _ports_complete_deallocate (pi);
+-- 
+2.0.0.rc0
+
diff --git a/debian/patches/0007-ext2fs-improve-enable-disable-_caching.patch b/debian/patches/0007-ext2fs-improve-enable-disable-_caching.patch
new file mode 100644
index 00000000..fa8931f5
--- /dev/null
+++ b/debian/patches/0007-ext2fs-improve-enable-disable-_caching.patch
@@ -0,0 +1,38 @@
+From e3b88fd752f6285d7cd07a87891ec83f5152cb5b Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Fri, 9 May 2014 10:07:28 +0200
+Subject: [PATCH 07/13] ext2fs: improve {enable,disable}_caching
+
+* ext2fs/pager.c (enable_caching, disable_caching): Iterate over the
+pager class instead of over both pager buckets.
+---
+ ext2fs/pager.c | 6 ++----
+ 1 file changed, 2 insertions(+), 4 deletions(-)
+
+diff --git a/ext2fs/pager.c b/ext2fs/pager.c
+index 017efcc..6328f3b 100644
+--- a/ext2fs/pager.c
++++ b/ext2fs/pager.c
+@@ -1409,8 +1409,7 @@ disable_caching ()
+ 
+   /* Loop through the pagers and turn off caching one by one,
+      synchronously.  That should cause termination of each pager. */
+-  ports_bucket_iterate (disk_pager_bucket, block_cache);
+-  ports_bucket_iterate (file_pager_bucket, block_cache);
++  ports_class_iterate (_pager_class, block_cache);
+ }
+ 
+ static void
+@@ -1438,8 +1437,7 @@ enable_caching ()
+       return 0;
+     }
+ 
+-  ports_bucket_iterate (disk_pager_bucket, enable_cache);
+-  ports_bucket_iterate (file_pager_bucket, enable_cache);
++  ports_class_iterate (_pager_class, enable_cache);
+ }
+ 
+ /* Tell diskfs if there are pagers exported, and if none, then
+-- 
+2.0.0.rc0
+
diff --git a/debian/patches/0008-fatfs-improve-enable-disable-_caching.patch b/debian/patches/0008-fatfs-improve-enable-disable-_caching.patch
new file mode 100644
index 00000000..5ec457af
--- /dev/null
+++ b/debian/patches/0008-fatfs-improve-enable-disable-_caching.patch
@@ -0,0 +1,48 @@
+From f7c6d4c90f6592340479f38662ba87ccfbee6025 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Fri, 9 May 2014 10:11:45 +0200
+Subject: [PATCH 08/13] fatfs: improve {enable,disable}_caching
+
+* fatfs/pager.c (enable_caching, disable_caching): Iterate over the
+pager class instead of over both pager buckets.
+---
+ fatfs/pager.c | 9 +++++----
+ 1 file changed, 5 insertions(+), 4 deletions(-)
+
+diff --git a/fatfs/pager.c b/fatfs/pager.c
+index f855ecf..7aa5c5e 100644
+--- a/fatfs/pager.c
++++ b/fatfs/pager.c
+@@ -23,6 +23,9 @@
+ #include <hurd/store.h>
+ #include "fatfs.h"
+ 
++/* XXX */
++#include "../libpager/priv.h"
++
+ /* A ports bucket to hold disk pager ports.  */
+ struct port_bucket *disk_pager_bucket;
+ 
+@@ -963,8 +966,7 @@ disable_caching ()
+ 
+   /* Loop through the pagers and turn off caching one by one,
+      synchronously.  That should cause termination of each pager.  */
+-  ports_bucket_iterate (disk_pager_bucket, block_cache);
+-  ports_bucket_iterate (file_pager_bucket, block_cache);
++  ports_class_iterate (_pager_class, block_cache);
+ }
+ 	  
+ static void
+@@ -992,8 +994,7 @@ enable_caching ()
+       return 0;
+     }
+ 
+-  ports_bucket_iterate (disk_pager_bucket, enable_cache);
+-  ports_bucket_iterate (file_pager_bucket, enable_cache);
++  ports_class_iterate (_pager_class, enable_cache);
+ }
+ 	    
+ /* Tell diskfs if there are pagers exported, and if none, then
+-- 
+2.0.0.rc0
+
diff --git a/debian/patches/0009-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0009-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
new file mode 100644
index 00000000..0fdd193c
--- /dev/null
+++ b/debian/patches/0009-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
@@ -0,0 +1,190 @@
+From 157ba3868fa568542cc67e50ca19e8b999651b51 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 09/13] 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.rc0
+
diff --git a/debian/patches/0010-fatfs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0010-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
new file mode 100644
index 00000000..885b35b2
--- /dev/null
+++ b/debian/patches/0010-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
@@ -0,0 +1,222 @@
+From 2acbb716cdea7fdb55c3745502c997adc5d89bd6 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 10/13] 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.rc0
+
diff --git a/debian/patches/0011-isofs-use-a-seperate-lock-to-protect-node_cache.patch b/debian/patches/0011-isofs-use-a-seperate-lock-to-protect-node_cache.patch
new file mode 100644
index 00000000..ca821a91
--- /dev/null
+++ b/debian/patches/0011-isofs-use-a-seperate-lock-to-protect-node_cache.patch
@@ -0,0 +1,222 @@
+From 7febcf4f9387354383d987707f9f236af7bfbb02 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 11/13] 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.rc0
+
diff --git a/debian/patches/0012-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch b/debian/patches/0012-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
new file mode 100644
index 00000000..bafa43af
--- /dev/null
+++ b/debian/patches/0012-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
@@ -0,0 +1,263 @@
+From 3eafe708df9be93503ca396bb0aad804143c0123 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 12/13] 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.rc0
+
diff --git a/debian/patches/0013-libdiskfs-lock-less-reference-counting-of-nodes.patch b/debian/patches/0013-libdiskfs-lock-less-reference-counting-of-nodes.patch
new file mode 100644
index 00000000..88a1add1
--- /dev/null
+++ b/debian/patches/0013-libdiskfs-lock-less-reference-counting-of-nodes.patch
@@ -0,0 +1,531 @@
+From bf8a8acbd5dc4cd737848163e44fd59ece6f9e8b 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 13/13] 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 ae1a150..2f5a76c 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 */
+ 
+@@ -198,8 +197,6 @@ 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. */
+@@ -448,7 +445,7 @@ 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
+@@ -611,9 +608,8 @@ 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 2b6ef2a..fc4f54c 100644
+--- a/libdiskfs/node-make.c
++++ b/libdiskfs/node-make.c
+@@ -36,8 +36,7 @@ diskfs_make_node (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.rc0
+
diff --git a/debian/patches/series b/debian/patches/series
index c08b0f99..179d45da 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -40,3 +40,16 @@ xkb-compat.patch
 
 mach-defpager-protected-payload.patch
 
+0001-include-add-lock-less-reference-counting-primitives.patch
+0002-libdiskfs-lock-less-reference-counting-for-peropen-o.patch
+0003-libtrivfs-lock-less-reference-counting-for-trivfs_pe.patch
+0004-libports-use-a-single-hash-table.patch
+0005-libports-lock-less-reference-counting-for-port_info-.patch
+0006-include-add-refcounts_demote-that-demotes-a-hard-ref.patch
+0007-ext2fs-improve-enable-disable-_caching.patch
+0008-fatfs-improve-enable-disable-_caching.patch
+0009-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
+0010-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
+0011-isofs-use-a-seperate-lock-to-protect-node_cache.patch
+0012-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
+0013-libdiskfs-lock-less-reference-counting-of-nodes.patch