add patch series

9 files changed, 2847 insertions, 0 deletions

diff --git a/debian/patches/0001-ext2fs-use-correct-type-for-disk-offsets.patch b/debian/patches/0001-ext2fs-use-correct-type-for-disk-offsets.patch
new file mode 100644
index 00000000..e24d72d3
--- /dev/null
+++ b/debian/patches/0001-ext2fs-use-correct-type-for-disk-offsets.patch
@@ -0,0 +1,38 @@
+From 70691ef59c67cb9e70bad5ed5c13a4d5408357d1 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Wed, 4 Jun 2014 17:26:06 +0200
+Subject: [PATCH 1/8] ext2fs: use correct type for disk offsets
+
+* ext2fs/dir.c (count_dirents): Use off_t for nb.
+(diskfs_get_directs): Likewise for blkno, nblks.
+---
+ ext2fs/dir.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/ext2fs/dir.c b/ext2fs/dir.c
+index 337314c..470b7e9 100644
+--- a/ext2fs/dir.c
++++ b/ext2fs/dir.c
+@@ -823,7 +823,7 @@ diskfs_drop_dirstat (struct node *dp, struct dirstat *ds)
+    write the answer down in its dirents array.  As a side affect
+    fill BUF with the block.  */
+ static error_t
+-count_dirents (struct node *dp, int nb, char *buf)
++count_dirents (struct node *dp, block_t nb, char *buf)
+ {
+   size_t amt;
+   char *offinblk;
+@@ -868,8 +868,8 @@ diskfs_get_directs (struct node *dp,
+ 		    vm_size_t bufsiz,
+ 		    int *amt)
+ {
+-  int blkno;
+-  int nblks;
++  block_t blkno;
++  block_t nblks;
+   int curentry;
+   char buf[DIRBLKSIZ];
+   char *bufp;
+-- 
+2.0.0
+
diff --git a/debian/patches/0002-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0002-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
new file mode 100644
index 00000000..fab3bcbd
--- /dev/null
+++ b/debian/patches/0002-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
@@ -0,0 +1,259 @@
+From f0cb840a68786c143ff8b994f48c4cb7f12f1aa8 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 2/8] 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 (nodecache_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 | 127 +++++++++++++++++++++++++++++++++++++++++----------------
+ 1 file changed, 91 insertions(+), 36 deletions(-)
+
+diff --git a/ext2fs/inode.c b/ext2fs/inode.c
+index ed78265..67c502a 100644
+--- a/ext2fs/inode.c
++++ b/ext2fs/inode.c
+@@ -46,8 +46,19 @@
+ #define	INOHASH(ino)	(((unsigned)(ino))%INOHSZ)
+ #endif
+ 
++/* The nodehash is a cache of nodes.
++
++   Access to nodehash and nodehash_nr_items is protected by
++   nodecache_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;
++/* nodecache_lock must be acquired before diskfs_node_refcnt_lock.  */
++static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ static error_t read_node (struct node *np);
+ 
+@@ -62,33 +73,37 @@ inode_init ()
+     nodehash[n] = 0;
+ }
+ 
++/* Lookup node with inode number INUM.  Returns NULL if the node is
++   not found in the node cache.  */
++static struct node *
++lookup (ino_t inum)
++{
++  struct node *np;
++  for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
++    if (np->cache_id == inum)
++      return np;
++  return NULL;
++}
++
+ /* Fetch inode INUM, set *NPP to the node structure;
+    gain one user reference and lock the node.  */
+ error_t
+ diskfs_cached_lookup (ino_t inum, struct node **npp)
+ {
+   error_t err;
+-  struct node *np;
++  struct node *np, *tmp;
+   struct disknode *dn;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_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);
+-	pthread_mutex_lock (&np->lock);
+-	*npp = np;
+-	return 0;
+-      }
++  pthread_rwlock_rdlock (&nodecache_lock);
++  np = lookup (inum);
++  if (np)
++    goto gotit;
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   /* Format specific data for the new node.  */
+   dn = malloc (sizeof (struct disknode));
+   if (! dn)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return ENOMEM;
+-    }
++    return ENOMEM;
+   dn->dirents = 0;
+   dn->dir_idx = 0;
+   dn->pager = 0;
+@@ -102,14 +117,24 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+   pthread_mutex_lock (&np->lock);
+ 
+   /* Put NP in NODEHASH.  */
++  pthread_rwlock_wrlock (&nodecache_lock);
++  tmp = lookup (inum);
++  if (tmp)
++    {
++      /* We lost a race.  */
++      diskfs_nput (np);
++      np = tmp;
++      goto gotit;
++    }
++
+   dn->hnext = nodehash[INOHASH(inum)];
+   if (dn->hnext)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  diskfs_nref_light (np);
+   nodehash_nr_items += 1;
+-
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   /* Get the contents of NP off disk.  */
+   err = read_node (np);
+@@ -131,6 +156,13 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+       *npp = np;
+       return 0;
+     }
++
++ gotit:
++  diskfs_nref (np);
++  pthread_rwlock_unlock (&nodecache_lock);
++  pthread_mutex_lock (&np->lock);
++  *npp = np;
++  return 0;
+ }
+ 
+ /* Lookup node INUM (which must have a reference already) and return it
+@@ -140,17 +172,12 @@ ifind (ino_t inum)
+ {
+   struct node *np;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+-    {
+-      if (np->cache_id != inum)
+-	continue;
++  pthread_rwlock_rdlock (&nodecache_lock);
++  np = lookup (inum);
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+-      assert (np->references);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return np;
+-    }
+-  assert (0);
++  assert (np);
++  return np;
+ }
+ 
+ /* The last reference to a node has gone away; drop
+@@ -158,11 +185,6 @@ 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 +202,35 @@ diskfs_node_norefs (struct node *np)
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_rwlock_wrlock (&nodecache_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);
++
++      /* An additional reference is acquired by libdiskfs across calls
++	 to diskfs_try_dropping_softrefs.  */
++      if (references > 1)
++	{
++	  /* A reference was reacquired through a hash table lookup.
++	     It's fine, we didn't touch anything yet. */
++	  pthread_rwlock_unlock (&nodecache_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_rwlock_unlock (&nodecache_lock);
++
+   drop_pager_softrefs (np);
+ }
+ 
+@@ -556,12 +607,12 @@ 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_rwlock_rdlock (&nodecache_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
++     nodecache_lock, but we can't hold this while locking the
+      individual node locks).  */
+   num_nodes = nodehash_nr_items;
+ 
+@@ -570,7 +621,7 @@ 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_rwlock_unlock (&nodecache_lock);
+       ext2_debug ("unable to allocate temporary node table");
+       return ENOMEM;
+     }
+@@ -580,10 +631,14 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+     for (node = nodehash[n]; node; node = node->dn->hnext)
+       {
+ 	*p++ = node;
++
++	/* We acquire a hard reference for node, but without using
++	   diskfs_nref.	 We do this so that diskfs_new_hardrefs will not
++	   get called.	*/
+ 	node->references++;
+       }
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   p = node_list;
+   while (num_nodes-- > 0)
+-- 
+2.0.0
+
diff --git a/debian/patches/0003-fatfs-use-a-seperate-lock-to-protect-nodehash.patch b/debian/patches/0003-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
new file mode 100644
index 00000000..8c8e0772
--- /dev/null
+++ b/debian/patches/0003-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
@@ -0,0 +1,303 @@
+From ee0bd55c8eb038a6a4c910b49ccc0f53440978f1 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 3/8] 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 (nodecache_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 | 146 ++++++++++++++++++++++++++++++++++++++++------------------
+ 1 file changed, 101 insertions(+), 45 deletions(-)
+
+diff --git a/fatfs/inode.c b/fatfs/inode.c
+index ed6f3f0..c3997d0 100644
+--- a/fatfs/inode.c
++++ b/fatfs/inode.c
+@@ -44,8 +44,19 @@
+ #define INOHASH(ino)    (((unsigned)(ino))%INOHSZ)
+ #endif
+ 
++/* The nodehash is a cache of nodes.
++
++   Access to nodehash and nodehash_nr_items is protected by
++   nodecache_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;
++/* nodecache_lock must be acquired before diskfs_node_refcnt_lock.  */
++static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ static error_t read_node (struct node *np, vm_address_t buf);
+ 
+@@ -58,33 +69,38 @@ inode_init ()
+     nodehash[n] = 0;
+ }
+ 
++/* Lookup node with inode number INUM.  Returns NULL if the node is
++   not found in the node cache.  */
++static struct node *
++lookup (ino_t inum)
++{
++  struct node *np;
++  for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
++    if (np->cache_id == inum)
++      return np;
++  return NULL;
++}
++
+ /* Fetch inode INUM, set *NPP to the node structure; gain one user
+    reference and lock the node.  */
+ error_t
+ diskfs_cached_lookup (ino64_t inum, struct node **npp)
+ {
+   error_t err;
+-  struct node *np;
++  struct node *np, *tmp;
+   struct disknode *dn;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_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);
+-        pthread_mutex_lock (&np->lock);
+-        *npp = np;
+-        return 0;
+-      }
++  pthread_rwlock_rdlock (&nodecache_lock);
++  np = lookup (inum);
++  if (np)
++    goto gotit;
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   /* Format specific data for the new node.  */
+   dn = malloc (sizeof (struct disknode));
+   if (! dn)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return ENOMEM;
+-    }
++    return ENOMEM;
++
+   dn->pager = 0;
+   dn->first = 0;
+   dn->last = 0;
+@@ -102,15 +118,25 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
+   pthread_mutex_lock (&np->lock);
+   
+   /* Put NP in NODEHASH.  */
++  pthread_rwlock_wrlock (&nodecache_lock);
++  tmp = lookup (inum);
++  if (tmp)
++    {
++      /* We lost a race.  */
++      diskfs_nput (np);
++      np = tmp;
++      goto gotit;
++    }
++
+   dn->hnext = nodehash[INOHASH(inum)];
+   if (dn->hnext)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  diskfs_nref_light (np);
+   nodehash_nr_items += 1;
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-  
+   /* Get the contents of NP off disk.  */
+   err = read_node (np, 0);
+ 
+@@ -121,6 +147,13 @@ diskfs_cached_lookup (ino64_t inum, struct node **npp)
+       *npp = np;
+       return 0;
+     }
++
++ gotit:
++  diskfs_nref (np);
++  pthread_rwlock_unlock (&nodecache_lock);
++  pthread_mutex_lock (&np->lock);
++  *npp = np;
++  return 0;
+ }
+ 
+ /* Fetch inode INUM, set *NPP to the node structure;
+@@ -133,24 +166,23 @@ 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_rwlock_rdlock (&nodecache_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_rwlock_unlock (&nodecache_lock);
+         pthread_mutex_lock (&np->lock);
+         *npp = np;
+         return 0;
+       }
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   /* Format specific data for the new node.  */
+   dn = malloc (sizeof (struct disknode));
+   if (! dn)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return ENOMEM;
+-    }
++    return ENOMEM;
++
+   dn->pager = 0;
+   dn->first = 0;
+   dn->last = 0;
+@@ -168,15 +200,16 @@ diskfs_cached_lookup_in_dirbuf (int inum, struct node **npp, vm_address_t buf)
+   pthread_mutex_lock (&np->lock);
+   
+   /* Put NP in NODEHASH.  */
++  pthread_rwlock_wrlock (&nodecache_lock);
+   dn->hnext = nodehash[INOHASH(inum)];
+   if (dn->hnext)
+     dn->hnext->dn->hprevp = &dn->hnext;
+   dn->hprevp = &nodehash[INOHASH(inum)];
+   nodehash[INOHASH(inum)] = np;
++  diskfs_nref_light (np);
+   nodehash_nr_items += 1;
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-  
+   /* Get the contents of NP off disk.  */
+   err = read_node (np, buf);
+ 
+@@ -196,17 +229,12 @@ ifind (ino_t inum)
+ {
+   struct node *np;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  for (np = nodehash[INOHASH(inum)]; np; np = np->dn->hnext)
+-    {
+-      if (np->cache_id != inum)
+-        continue;
++  pthread_rwlock_rdlock (&nodecache_lock);
++  np = lookup (inum);
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+-      assert (np->references);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return np;
+-    }
+-  assert (0);
++  assert (np);
++  return np;
+ }
+ 
+ /* The last reference to a node has gone away; drop it from the hash
+@@ -216,11 +244,6 @@ 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 +274,35 @@ diskfs_node_norefs (struct node *np)
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_rwlock_wrlock (&nodecache_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);
++
++      /* An additional reference is acquired by libdiskfs across calls
++	 to diskfs_try_dropping_softrefs.  */
++      if (references > 1)
++	{
++	  /* A reference was reacquired through a hash table lookup.
++	     It's fine, we didn't touch anything yet. */
++	  pthread_rwlock_unlock (&nodecache_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_rwlock_unlock (&nodecache_lock);
++
+   drop_pager_softrefs (np);
+ }
+ 
+@@ -554,12 +606,12 @@ 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_rwlock_rdlock (&nodecache_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
++     nodecache_lock, but we can't hold this while locking the
+      individual node locks).  */
+ 
+   num_nodes = nodehash_nr_items;
+@@ -570,10 +622,14 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+     for (node = nodehash[n]; node; node = node->dn->hnext)
+       {
+         *p++ = node;
+-        node->references++;
++
++	/* We acquire a hard reference for node, but without using
++	   diskfs_nref.	 We do this so that diskfs_new_hardrefs will not
++	   get called.	*/
++	node->references++;
+       }
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   p = node_list;
+   while (num_nodes-- > 0)
+-- 
+2.0.0
+
diff --git a/debian/patches/0004-isofs-use-a-seperate-lock-to-protect-node_cache.patch b/debian/patches/0004-isofs-use-a-seperate-lock-to-protect-node_cache.patch
new file mode 100644
index 00000000..bf40bdc1
--- /dev/null
+++ b/debian/patches/0004-isofs-use-a-seperate-lock-to-protect-node_cache.patch
@@ -0,0 +1,310 @@
+From 26ecd598cfb0713f85d7c87ab4c9ef9e758e58a4 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 4/8] 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 (nodecache_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 | 146 +++++++++++++++++++++++++++++++++++++++++-----------------
+ 1 file changed, 105 insertions(+), 41 deletions(-)
+
+diff --git a/isofs/inode.c b/isofs/inode.c
+index cdc05ae..3941580 100644
+--- a/isofs/inode.c
++++ b/isofs/inode.c
+@@ -48,35 +48,53 @@ 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 nodecache_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;
++/* nodecache_lock must be acquired before diskfs_node_refcnt_lock.  */
++static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ /* Forward */
+ static error_t read_disknode (struct node *,
+ 			      struct dirrect *, struct rrip_lookup *);
+ 
+ 
++/* Lookup node with id ID.  Returns NULL if the node is not found in
++   the node cache.  */
++static struct node *
++lookup (off_t id)
++{
++  int i;
++  for (i = 0; i < node_cache_size; i++)
++    if (node_cache[i].id == id
++	&& node_cache[i].np)
++      return node_cache[i].np;
++  return NULL;
++}
++
+ /* 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. nodecache_lock must be held
+    on entry to the call, and will be released iff the node was found
+    in the cache. */
+ void
+ inode_cache_find (off_t id, struct node **npp)
+ {
+-  int i;
+-
+-  for (i = 0; i < node_cache_size; i++)
+-    if (node_cache[i].id == id
+-	&& node_cache[i].np)
+-      {
+-	*npp = node_cache[i].np;
+-	(*npp)->references++;
+-	pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-	pthread_mutex_lock (&(*npp)->lock);
+-	return;
+-      }
+-  *npp = 0;
++  *npp = lookup (id);
++  if (*npp)
++    {
++      diskfs_nref (*npp);
++      pthread_rwlock_unlock (&nodecache_lock);
++      pthread_mutex_lock (&(*npp)->lock);
++    }
+ }
+ 
+ 
+@@ -92,7 +110,7 @@ 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. nodecache_lock must be held. */
+ void
+ cache_inode (struct node *np, struct dirrect *record,
+ 	    struct rrip_lookup *rr)
+@@ -137,6 +155,7 @@ cache_inode (struct node *np, struct dirrect *record,
+   c->id = id;
+   c->dr = record;
+   c->file_start = np->dn->file_start;
++  diskfs_nref_light (np);
+   c->np = np;
+ 
+   /* PLUS 1 so that we don't store zero cache ID's (not allowed by diskfs) */
+@@ -155,7 +174,7 @@ 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_rwlock_rdlock (&nodecache_lock);
+   assert (id < node_cache_size);
+ 
+   np = node_cache[id].np;
+@@ -166,6 +185,8 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+       struct rrip_lookup rr;
+       struct disknode *dn;
+ 
++      pthread_rwlock_unlock (&nodecache_lock);
++
+       rrip_lookup (node_cache[id].dr, &rr, 1);
+ 
+       /* We should never cache the wrong directory entry */
+@@ -174,7 +195,7 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+       dn = malloc (sizeof (struct disknode));
+       if (!dn)
+ 	{
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	  pthread_rwlock_unlock (&nodecache_lock);
+ 	  release_rrip (&rr);
+ 	  return ENOMEM;
+ 	}
+@@ -185,16 +206,26 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+       if (!np)
+ 	{
+ 	  free (dn);
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	  pthread_rwlock_unlock (&nodecache_lock);
+ 	  release_rrip (&rr);
+ 	  return ENOMEM;
+ 	}
+       np->cache_id = id + 1;	/* see above for rationale for increment */
+       pthread_mutex_lock (&np->lock);
++
++      pthread_rwlock_wrlock (&nodecache_lock);
++      if (c->np != NULL)
++        {
++          /* We lost a race.  */
++          diskfs_nput (np);
++          np = c->np;
++          goto gotit;
++        }
+       c->np = np;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      diskfs_nref_light (np);
++      pthread_rwlock_unlock (&nodecache_lock);
+ 
+-      err = read_disknode (np, node_cache[id].dr, &rr);
++      err = read_disknode (np, dn->dr, &rr);
+       if (!err)
+ 	*npp = np;
+ 
+@@ -203,9 +234,9 @@ diskfs_cached_lookup (ino_t id, struct node **npp)
+       return err;
+     }
+ 
+-
+-  np->references++;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++ gotit:
++  diskfs_nref (np);
++  pthread_rwlock_unlock (&nodecache_lock);
+   pthread_mutex_lock (&np->lock);
+   *npp = np;
+   return 0;
+@@ -307,7 +338,8 @@ load_inode (struct node **npp, struct dirrect *record,
+   error_t err;
+   off_t file_start;
+   struct disknode *dn;
+-  struct node *np;
++  struct node *np, *tmp;
++  off_t id;
+ 
+   err = calculate_file_start (record, &file_start, rr);
+   if (err)
+@@ -315,27 +347,23 @@ load_inode (struct node **npp, struct dirrect *record,
+   if (rr->valid & VALID_CL)
+     record = rr->realdirent;
+ 
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-
+   /* First check the cache */
+   if (use_file_start_id (record, rr))
+-    inode_cache_find (file_start << store->log2_block_size, npp);
++    id = file_start << store->log2_block_size;
+   else
+-    inode_cache_find ((off_t) ((void *) record - (void *) disk_image), npp);
++    id = (off_t) ((void *) record - (void *) disk_image);
+ 
++  pthread_rwlock_rdlock (&nodecache_lock);
++  inode_cache_find (id, npp);
+   if (*npp)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return 0;
+-    }
++    return 0;
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   /* Create a new node */
+   dn = malloc (sizeof (struct disknode));
+   if (!dn)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      return ENOMEM;
+-    }
++    return ENOMEM;
++
+   dn->fileinfo = 0;
+   dn->dr = record;
+   dn->file_start = file_start;
+@@ -344,14 +372,25 @@ load_inode (struct node **npp, struct dirrect *record,
+   if (!np)
+     {
+       free (dn);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+       return ENOMEM;
+     }
+ 
+   pthread_mutex_lock (&np->lock);
+ 
++  pthread_rwlock_wrlock (&nodecache_lock);
++  tmp = lookup (id);
++  if (tmp)
++    {
++      /* We lost a race.  */
++      diskfs_nput (np);
++      diskfs_nref (tmp);
++      *npp = tmp;
++      pthread_rwlock_unlock (&nodecache_lock);
++      return 0;
++    }
++
+   cache_inode (np, record, rr);
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_rwlock_unlock (&nodecache_lock);
+ 
+   err = read_disknode (np, record, rr);
+   *npp = np;
+@@ -505,9 +544,6 @@ 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 +557,34 @@ diskfs_node_norefs (struct node *np)
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_rwlock_wrlock (&nodecache_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);
++
++      /* An additional reference is acquired by libdiskfs across calls
++	 to diskfs_try_dropping_softrefs.  */
++      if (references > 1)
++	{
++	  /* A reference was reacquired through a hash table lookup.
++	     It's fine, we didn't touch anything yet. */
++	  pthread_rwlock_unlock (&nodecache_lock);
++	  return;
++	}
++
++      node_cache[np->cache_id - 1].np = 0;
++      np->cache_id = 0;
++      diskfs_nrele_light (np);
++    }
++  pthread_rwlock_unlock (&nodecache_lock);
++
+   drop_pager_softrefs (np);
+ }
+ 
+-- 
+2.0.0
+
diff --git a/debian/patches/0005-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch b/debian/patches/0005-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
new file mode 100644
index 00000000..da092aaa
--- /dev/null
+++ b/debian/patches/0005-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
@@ -0,0 +1,314 @@
+From 2dd7733297eeb6d0e941d3cb8303c3f91c1dc9f6 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 5/8] 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 atomic operations to
+access the state related to memory consumption. 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/tmpfs.h (num_files, tmpfs_space_used): Use atomic operations
+for these variables.
+(adjust_used): Use atomic operations.
+(get_used): New convenience function to atomically retrieve
+tmpfs_space_used.
+* 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): Do not remove the node from all_nodes.  This
+actually looks like a mistake, I do not know why they did that here as
+well as in diskfs_free_node.
+(diskfs_try_dropping_softrefs): Check whether someone reacquired a
+reference, and if so hold on to our light reference.
+(diskfs_grow): Use atomic operations.
+* tmpfs/tmpfs.c (diskfs_set_statfs): Likewise.
+---
+ tmpfs/node.c  | 107 ++++++++++++++++++++++++++++++++++++++++++----------------
+ tmpfs/tmpfs.c |   6 ++--
+ tmpfs/tmpfs.h |  20 +++++++----
+ 3 files changed, 94 insertions(+), 39 deletions(-)
+
+diff --git a/tmpfs/node.c b/tmpfs/node.c
+index acc029a..24ad0bd 100644
+--- a/tmpfs/node.c
++++ b/tmpfs/node.c
+@@ -29,8 +29,19 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+ unsigned int num_files;
+ static unsigned int gen;
+ 
++/* all_nodes is a list of all nodes.
++
++   Access to all_nodes and all_nodes_nr_items is protected by
++   all_nodes_lock.
++
++   Every node in 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.  */
+ struct node *all_nodes;
+ static size_t all_nodes_nr_items;
++/* all_nodes_lock must be acquired before diskfs_node_refcnt_lock.  */
++pthread_rwlock_t all_nodes_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ error_t
+ diskfs_alloc_node (struct node *dp, mode_t mode, struct node **npp)
+@@ -40,18 +51,17 @@ 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);
+-  if (round_page (tmpfs_space_used + sizeof *dn) / vm_page_size
++
++  if (round_page (get_used () + sizeof *dn) / vm_page_size
+       > tmpfs_page_limit)
+     {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++      pthread_rwlock_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);
++  __atomic_add_fetch (&num_files, 1, __ATOMIC_RELAXED);
++  adjust_used (sizeof *dn);
+ 
+   dn->type = IFTODT (mode & S_IFMT);
+   return diskfs_cached_lookup ((ino_t) (uintptr_t) dn, npp);
+@@ -75,15 +85,19 @@ diskfs_free_node (struct node *np, mode_t mode)
+       free (np->dn->u.lnk);
+       break;
+     }
++
++  pthread_rwlock_wrlock (&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;
++  pthread_rwlock_unlock (&all_nodes_lock);
++
+   free (np->dn);
+   np->dn = 0;
+ 
+-  --num_files;
+-  tmpfs_space_used -= sizeof *np->dn;
++  __atomic_sub_fetch (&num_files, 1, __ATOMIC_RELAXED);
++  adjust_used (-sizeof *np->dn);
+ }
+ 
+ void
+@@ -117,14 +131,6 @@ 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);
+@@ -167,30 +173,34 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+ 
+   assert (npp);
+ 
++  pthread_rwlock_rdlock (&all_nodes_lock);
+   if (dn->hprevp != 0)		/* There is already a node.  */
+-    {
+-      np = *dn->hprevp;
+-      assert (np->dn == dn);
+-      assert (*dn->hprevp == np);
+-
+-      diskfs_nref (np);
+-    }
++    goto gotit;
+   else
+     /* Create the new node.  */
+     {
+       struct stat *st;
++      pthread_rwlock_unlock (&all_nodes_lock);
+ 
+       np = diskfs_make_node (dn);
+       np->cache_id = (ino_t) (uintptr_t) dn;
+ 
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
++      pthread_rwlock_wrlock (&all_nodes_lock);
++      if (dn->hprevp != NULL)
++        {
++          /* We lost a race.  */
++          diskfs_nrele (np);
++          goto gotit;
++        }
++
+       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_rwlock_unlock (&all_nodes_lock);
+ 
+       st = &np->dn_stat;
+       memset (st, 0, sizeof *st);
+@@ -220,6 +230,16 @@ diskfs_cached_lookup (ino_t inum, struct node **npp)
+   pthread_mutex_lock (&np->lock);
+   *npp = np;
+   return 0;
++
++ gotit:
++  np = *dn->hprevp;
++  assert (np->dn == dn);
++  assert (*dn->hprevp == np);
++  diskfs_nref (np);
++  pthread_rwlock_unlock (&all_nodes_lock);
++  pthread_mutex_lock (&np->lock);
++  *npp = np;
++  return 0;
+ }
+ 
+ error_t
+@@ -229,12 +249,12 @@ 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_rwlock_rdlock (&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 +263,14 @@ diskfs_node_iterate (error_t (*fun) (struct node *))
+   for (node = all_nodes; node != 0; node = node->dn->hnext)
+     {
+       *p++ = node;
++
++      /* We acquire a hard reference for node, but without using
++	 diskfs_nref.  We do this so that diskfs_new_hardrefs will not
++	 get called.  */
+       node->references++;
+     }
+ 
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  pthread_rwlock_unlock (&all_nodes_lock);
+ 
+   p = node_list;
+   while (num_nodes-- > 0)
+@@ -272,6 +296,31 @@ diskfs_node_iterate (error_t (*fun) (struct node *))
+ void
+ diskfs_try_dropping_softrefs (struct node *np)
+ {
++  pthread_rwlock_wrlock (&all_nodes_lock);
++  if (np->cache_id != 0)
++    {
++      /* Check if someone reacquired a reference.  */
++      unsigned int references;
++      pthread_spin_lock (&diskfs_node_refcnt_lock);
++      references = np->references;
++      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++      /* An additional reference is acquired by libdiskfs across calls
++	 to diskfs_try_dropping_softrefs.  */
++      if (references > 1)
++	{
++	  /* A reference was reacquired.  It's fine, we didn't touch
++	     anything yet. */
++	  pthread_rwlock_unlock (&all_nodes_lock);
++	  return;
++	}
++
++      /* Just let go of the weak reference.  The node will be removed
++	 from all_nodes in diskfs_free_node.  */
++      np->cache_id = 0;
++      diskfs_nrele_light (np);
++    }
++  pthread_rwlock_unlock (&all_nodes_lock);
+ }
+ 
+ /* The user must define this funcction.  Node NP has some light
+@@ -447,7 +496,7 @@ diskfs_grow (struct node *np, off_t size, struct protid *cred)
+ 
+   off_t set_size = size;
+   size = round_page (size);
+-  if (round_page (tmpfs_space_used + size - np->allocsize)
++  if (round_page (get_used () + size - np->allocsize)
+       / vm_page_size > tmpfs_page_limit)
+     return ENOSPC;
+ 
+diff --git a/tmpfs/tmpfs.c b/tmpfs/tmpfs.c
+index 718c6d8..0aace25 100644
+--- a/tmpfs/tmpfs.c
++++ b/tmpfs/tmpfs.c
+@@ -67,10 +67,8 @@ 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);
+-  st->f_files = num_files;
+-  pages = round_page (tmpfs_space_used) / vm_page_size;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  st->f_files = __atomic_load_n (&num_files, __ATOMIC_RELAXED);
++  pages = round_page (get_used ()) / vm_page_size;
+ 
+   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..ad47200 100644
+--- a/tmpfs/tmpfs.h
++++ b/tmpfs/tmpfs.h
+@@ -69,17 +69,25 @@ struct tmpfs_dirent
+   char name[0];
+ };
+ 
+-extern unsigned int num_files;
+-extern off_t tmpfs_page_limit, tmpfs_space_used;
+-
++extern off_t tmpfs_page_limit;
+ extern mach_port_t default_pager;
+ 
++/* These two must be accessed using atomic operations.  */
++extern unsigned int num_files;
++extern off_t tmpfs_space_used;
++
++/* Convenience function to adjust tmpfs_space_used.  */
+ static inline void
+ adjust_used (off_t change)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  tmpfs_space_used += change;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  __atomic_add_fetch (&num_files, change, __ATOMIC_RELAXED);
++}
++
++/* Convenience function to get tmpfs_space_used.  */
++static inline off_t
++get_used (void)
++{
++  return __atomic_load_n (&num_files, __ATOMIC_RELAXED);
+ }
+ 
+ #endif
+-- 
+2.0.0
+
diff --git a/debian/patches/0006-libdiskfs-lock-less-reference-counting-of-nodes.patch b/debian/patches/0006-libdiskfs-lock-less-reference-counting-of-nodes.patch
new file mode 100644
index 00000000..8a442b42
--- /dev/null
+++ b/debian/patches/0006-libdiskfs-lock-less-reference-counting-of-nodes.patch
@@ -0,0 +1,611 @@
+From 52da6186728c8557b885d1eced550c18227dcb84 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 6/8] 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          | 15 +++++---------
+ fatfs/inode.c           | 27 ++++++++-----------------
+ isofs/inode.c           | 13 ++++--------
+ libdiskfs/diskfs.h      | 15 ++++++--------
+ 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            | 15 +++++---------
+ 15 files changed, 92 insertions(+), 157 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 67c502a..714d1a2 100644
+--- a/ext2fs/inode.c
++++ b/ext2fs/inode.c
+@@ -57,7 +57,6 @@
+    through the nodehash.  */
+ static struct node *nodehash[INOHSZ];
+ static size_t nodehash_nr_items;
+-/* nodecache_lock must be acquired before diskfs_node_refcnt_lock.  */
+ static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ static error_t read_node (struct node *np);
+@@ -207,14 +206,10 @@ 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);
+-
+-      /* An additional reference is acquired by libdiskfs across calls
+-	 to diskfs_try_dropping_softrefs.  */
+-      if (references > 1)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++
++      if (result.hard > 0)
+ 	{
+ 	  /* A reference was reacquired through a hash table lookup.
+ 	     It's fine, we didn't touch anything yet. */
+@@ -635,7 +630,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+ 	/* We acquire a hard reference for node, but without using
+ 	   diskfs_nref.	 We do this so that diskfs_new_hardrefs will not
+ 	   get called.	*/
+-	node->references++;
++	refcounts_ref (&node->refcounts, NULL);
+       }
+ 
+   pthread_rwlock_unlock (&nodecache_lock);
+diff --git a/fatfs/inode.c b/fatfs/inode.c
+index c3997d0..0cdca5e 100644
+--- a/fatfs/inode.c
++++ b/fatfs/inode.c
+@@ -55,7 +55,6 @@
+    through the nodehash.  */
+ static struct node *nodehash[INOHSZ];
+ static size_t nodehash_nr_items;
+-/* nodecache_lock must be acquired before diskfs_node_refcnt_lock.  */
+ static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ static error_t read_node (struct node *np, vm_address_t buf);
+@@ -254,14 +253,8 @@ 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);
+ 
+@@ -279,14 +272,10 @@ 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);
+-
+-      /* An additional reference is acquired by libdiskfs across calls
+-	 to diskfs_try_dropping_softrefs.  */
+-      if (references > 1)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++
++      if (result.hard > 0)
+ 	{
+ 	  /* A reference was reacquired through a hash table lookup.
+ 	     It's fine, we didn't touch anything yet. */
+@@ -391,7 +380,7 @@ 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);
+ 
+@@ -626,7 +615,7 @@ diskfs_node_iterate (error_t (*fun)(struct node *))
+ 	/* We acquire a hard reference for node, but without using
+ 	   diskfs_nref.	 We do this so that diskfs_new_hardrefs will not
+ 	   get called.	*/
+-	node->references++;
++	refcounts_ref (&node->refcounts, NULL);
+       }
+ 
+   pthread_rwlock_unlock (&nodecache_lock);
+@@ -837,7 +826,7 @@ 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 3941580..4c75510 100644
+--- a/isofs/inode.c
++++ b/isofs/inode.c
+@@ -60,7 +60,6 @@ struct node_cache
+ static int node_cache_size = 0;
+ static int node_cache_alloced = 0;
+ struct node_cache *node_cache = 0;
+-/* nodecache_lock must be acquired before diskfs_node_refcnt_lock.  */
+ static pthread_rwlock_t nodecache_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ /* Forward */
+@@ -564,14 +563,10 @@ 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);
+-
+-      /* An additional reference is acquired by libdiskfs across calls
+-	 to diskfs_try_dropping_softrefs.  */
+-      if (references > 1)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++
++      if (result.hard > 0)
+ 	{
+ 	  /* 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 e328527..a030389 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. */
+@@ -448,14 +445,15 @@ 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
+    references, but has just lost its last hard references.  Take steps
+    so that if any light references can be freed, they are.  NP is locked
+    as is the pager refcount lock.  This function will be called after
+-   diskfs_lost_hardrefs.  */
++   diskfs_lost_hardrefs.  An additional light reference is acquired by
++   libdiskfs across calls to this function.  */
+ void diskfs_try_dropping_softrefs (struct node *np);
+ 
+ /* The user must define this funcction.  Node NP has some light
+@@ -611,9 +609,8 @@ 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 7a7f248..6c94faa 100644
+--- a/libdiskfs/init-init.c
++++ b/libdiskfs/init-init.c
+@@ -41,8 +41,6 @@ int _diskfs_noatime;
+ 
+ struct hurd_port _diskfs_exec_portcell;
+ 
+-pthread_spinlock_t diskfs_node_refcnt_lock = PTHREAD_SPINLOCK_INITIALIZER;
+-
+ pthread_spinlock_t _diskfs_control_lock = PTHREAD_SPINLOCK_INITIALIZER;
+ int _diskfs_ncontrol_ports;
+ 
+diff --git a/libdiskfs/node-drop.c b/libdiskfs/node-drop.c
+index 83eb590..fab3cfa 100644
+--- a/libdiskfs/node-drop.c
++++ b/libdiskfs/node-drop.c
+@@ -31,9 +31,8 @@ free_modreqs (struct modreq *mr)
+ }
+ 
+ 
+-/* Node NP now has no more references; clean all state.  The
+-   diskfs_node_refcnt_lock must be held, and will be released
+-   upon return.  NP must be locked.  */
++/* Node NP now has no more references; clean all state.  NP must be
++   locked.  */
+ void
+ diskfs_drop_node (struct node *np)
+ {
+@@ -60,8 +59,7 @@ diskfs_drop_node (struct node *np)
+ 	     and an nput.  The next time through, this routine
+ 	     will notice that the size is zero, and not have to
+ 	     do anything. */
+-	  np->references++;
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++	  refcounts_ref (&np->refcounts, NULL);
+ 	  diskfs_truncate (np, 0);
+ 	  
+ 	  /* Force allocsize to zero; if truncate consistently fails this
+@@ -94,5 +92,4 @@ diskfs_drop_node (struct node *np)
+   assert (!np->sockaddr);
+ 
+   diskfs_node_norefs (np);
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+ }
+diff --git a/libdiskfs/node-make.c b/libdiskfs/node-make.c
+index ff0cc0d..c7ca3b0 100644
+--- a/libdiskfs/node-make.c
++++ b/libdiskfs/node-make.c
+@@ -29,8 +29,7 @@ init_node (struct node *np, struct disknode *dn)
+   np->dn_stat_dirty = 0;
+ 
+   pthread_mutex_init (&np->lock, NULL);
+-  np->references = 1;
+-  np->light_references = 0;
++  refcounts_init (&np->refcounts, 1, 0);
+   np->owner = 0;
+   np->sockaddr = MACH_PORT_NULL;
+ 
+diff --git a/libdiskfs/node-nput.c b/libdiskfs/node-nput.c
+index 5043ad1..2935ae2 100644
+--- a/libdiskfs/node-nput.c
++++ b/libdiskfs/node-nput.c
+@@ -26,56 +26,44 @@
+ void
+ diskfs_nput (struct node *np)
+ {
+-  int tried_drop_softrefs = 0;
++  struct references result;
+ 
+- loop:
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->references);
+-  np->references--;
+-  if (np->references + np->light_references == 0)
+-    diskfs_drop_node (np);
+-  else if (np->references == 0 && !tried_drop_softrefs)
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  /* While we call the diskfs_try_dropping_softrefs, we need to hold
++     one reference.  We use a weak reference for this purpose, which
++     we acquire by demoting our hard reference to a weak one.  */
++  refcounts_demote (&np->refcounts, &result);
+ 
++  if (result.hard == 0)
++    {
+       /* This is our cue that something akin to "last process closes file"
+ 	 in the POSIX.1 sense happened, so make sure any pending node time
+ 	 updates now happen in a timely fashion.  */
+       diskfs_set_node_times (np);
+-
+       diskfs_lost_hardrefs (np);
+       if (!np->dn_stat.st_nlink)
+ 	{
+-	  /* There are no links.  If there are soft references that
+-	     can be dropped, we can't let them postpone deallocation.
+-	     So attempt to drop them.  But that's a user-supplied
+-	     routine, which might result in further recursive calls to
+-	     the ref-counting system.  So we have to reacquire our
+-	     reference around the call to forestall disaster. */
+-	  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-	  np->references++;
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+ 	  if (np->sockaddr != MACH_PORT_NULL)
+ 	    {
+ 	      mach_port_deallocate (mach_task_self (), np->sockaddr);
+ 	      np->sockaddr = MACH_PORT_NULL;
+ 	    }
+ 
++	  /* There are no links.  If there are soft references that
++	     can be dropped, we can't let them postpone deallocation.
++	     So attempt to drop them.  But that's a user-supplied
++	     routine, which might result in further recursive calls to
++	     the ref-counting system.  This is not a problem, as we
++	     hold a weak reference ourselves. */
+ 	  diskfs_try_dropping_softrefs (np);
+-
+-	  /* But there's no value in looping forever in this
+-	     routine; only try to drop soft refs once. */
+-	  tried_drop_softrefs = 1;
+-
+-	  /* Now we can drop the reference back... */
+-	  goto loop;
+ 	}
+       pthread_mutex_unlock (&np->lock);
+     }
+-  else
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      pthread_mutex_unlock (&np->lock);
+-    }
++
++  /* Finally get rid of our reference.  */
++  refcounts_deref_weak (&np->refcounts, &result);
++
++  if (result.hard == 0 && result.weak == 0)
++    diskfs_drop_node (np);
++
++  pthread_mutex_unlock (&np->lock);
+ }
+diff --git a/libdiskfs/node-nputl.c b/libdiskfs/node-nputl.c
+index 1959665..8dac16e 100644
+--- a/libdiskfs/node-nputl.c
++++ b/libdiskfs/node-nputl.c
+@@ -25,14 +25,10 @@
+ void
+ diskfs_nput_light (struct node *np)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->light_references);
+-  np->light_references--;
+-  if (np->references + np->light_references == 0)
++  struct references result;
++  refcounts_deref_weak (&np->refcounts, &result);
++  if (result.hard == 0 && result.weak == 0)
+     diskfs_drop_node (np);
+   else
+-    {
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-      pthread_mutex_unlock (&np->lock);
+-    }
++    pthread_mutex_unlock (&np->lock);
+ }
+diff --git a/libdiskfs/node-nref.c b/libdiskfs/node-nref.c
+index 13cea05..89ffa4f 100644
+--- a/libdiskfs/node-nref.c
++++ b/libdiskfs/node-nref.c
+@@ -26,12 +26,10 @@
+ void
+ diskfs_nref (struct node *np)
+ {
+-  int new_hardref;
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  np->references++;
+-  new_hardref = (np->references == 1);
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-  if (new_hardref)
++  struct references result;
++  refcounts_ref (&np->refcounts, &result);
++  assert (result.hard > 1 || result.weak > 0);
++  if (result.hard == 1)
+     {
+       pthread_mutex_lock (&np->lock);
+       diskfs_new_hardrefs (np);
+diff --git a/libdiskfs/node-nrefl.c b/libdiskfs/node-nrefl.c
+index 9692247..b7af409 100644
+--- a/libdiskfs/node-nrefl.c
++++ b/libdiskfs/node-nrefl.c
+@@ -24,7 +24,7 @@
+ void
+ diskfs_nref_light (struct node *np)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  np->light_references++;
+-  pthread_spin_unlock (&diskfs_node_refcnt_lock);
++  struct references result;
++  refcounts_ref_weak (&np->refcounts, &result);
++  assert (result.hard > 0 || result.weak > 1);
+ }
+diff --git a/libdiskfs/node-nrele.c b/libdiskfs/node-nrele.c
+index cc68089..d962846 100644
+--- a/libdiskfs/node-nrele.c
++++ b/libdiskfs/node-nrele.c
+@@ -28,38 +28,36 @@
+ void
+ diskfs_nrele (struct node *np)
+ {
+-  int tried_drop_softrefs = 0;
++  struct references result;
+ 
+- loop:
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->references);
+-  np->references--;
+-  if (np->references + np->light_references == 0)
+-    {
+-      pthread_mutex_lock (&np->lock);
+-      diskfs_drop_node (np);
+-    }
+-  else if (np->references == 0)
++  /* While we call the diskfs_try_dropping_softrefs, we need to hold
++     one reference.  We use a weak reference for this purpose, which
++     we acquire by demoting our hard reference to a weak one.  */
++  refcounts_demote (&np->refcounts, &result);
++
++  if (result.hard == 0)
+     {
+       pthread_mutex_lock (&np->lock);
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+       diskfs_lost_hardrefs (np);
+-      if (!np->dn_stat.st_nlink && !tried_drop_softrefs)
++      if (!np->dn_stat.st_nlink)
+ 	{
+-	  /* Same issue here as in nput; see that for explanation */
+-	  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-	  np->references++;
+-	  pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
++	  /* There are no links.  If there are soft references that
++	     can be dropped, we can't let them postpone deallocation.
++	     So attempt to drop them.  But that's a user-supplied
++	     routine, which might result in further recursive calls to
++	     the ref-counting system.  This is not a problem, as we
++	     hold a weak reference ourselves. */
+ 	  diskfs_try_dropping_softrefs (np);
+-	  tried_drop_softrefs = 1;
+-
+-	  /* Now we can drop the reference back... */
+-	  pthread_mutex_unlock (&np->lock);
+-	  goto loop;
+ 	}
+       pthread_mutex_unlock (&np->lock);
+     }
+-  else
+-    pthread_spin_unlock (&diskfs_node_refcnt_lock);
++
++  /* Finally get rid of our reference.  */
++  refcounts_deref_weak (&np->refcounts, &result);
++
++  if (result.hard == 0 && result.weak == 0)
++    {
++      pthread_mutex_lock (&np->lock);
++      diskfs_drop_node (np);
++    }
+ }
+diff --git a/libdiskfs/node-nrelel.c b/libdiskfs/node-nrelel.c
+index ee53b22..dc4f920 100644
+--- a/libdiskfs/node-nrelel.c
++++ b/libdiskfs/node-nrelel.c
+@@ -26,14 +26,11 @@
+ void
+ diskfs_nrele_light (struct node *np)
+ {
+-  pthread_spin_lock (&diskfs_node_refcnt_lock);
+-  assert (np->light_references);
+-  np->light_references--;
+-  if (np->references + np->light_references == 0)
++  struct references result;
++  refcounts_deref_weak (&np->refcounts, &result);
++  if (result.hard == 0 && result.weak == 0)
+     {
+       pthread_mutex_lock (&np->lock);
+       diskfs_drop_node (np);
+     }
+-  else
+-    pthread_spin_unlock (&diskfs_node_refcnt_lock);
+ }
+diff --git a/tmpfs/node.c b/tmpfs/node.c
+index 24ad0bd..bbc5ba8 100644
+--- a/tmpfs/node.c
++++ b/tmpfs/node.c
+@@ -40,7 +40,6 @@ static unsigned int gen;
+    reference.  */
+ struct node *all_nodes;
+ static size_t all_nodes_nr_items;
+-/* all_nodes_lock must be acquired before diskfs_node_refcnt_lock.  */
+ pthread_rwlock_t all_nodes_lock = PTHREAD_RWLOCK_INITIALIZER;
+ 
+ error_t
+@@ -267,7 +266,7 @@ diskfs_node_iterate (error_t (*fun) (struct node *))
+       /* We acquire a hard reference for node, but without using
+ 	 diskfs_nref.  We do this so that diskfs_new_hardrefs will not
+ 	 get called.  */
+-      node->references++;
++      refcounts_ref (&node->refcounts, NULL);
+     }
+ 
+   pthread_rwlock_unlock (&all_nodes_lock);
+@@ -300,14 +299,10 @@ diskfs_try_dropping_softrefs (struct node *np)
+   if (np->cache_id != 0)
+     {
+       /* Check if someone reacquired a reference.  */
+-      unsigned int references;
+-      pthread_spin_lock (&diskfs_node_refcnt_lock);
+-      references = np->references;
+-      pthread_spin_unlock (&diskfs_node_refcnt_lock);
+-
+-      /* An additional reference is acquired by libdiskfs across calls
+-	 to diskfs_try_dropping_softrefs.  */
+-      if (references > 1)
++      struct references result;
++      refcounts_references (&np->refcounts, &result);
++
++      if (result.hard > 0)
+ 	{
+ 	  /* A reference was reacquired.  It's fine, we didn't touch
+ 	     anything yet. */
+-- 
+2.0.0
+
diff --git a/debian/patches/0007-libports-use-a-global-hash-table-for-the-lookups.patch b/debian/patches/0007-libports-use-a-global-hash-table-for-the-lookups.patch
new file mode 100644
index 00000000..5219875d
--- /dev/null
+++ b/debian/patches/0007-libports-use-a-global-hash-table-for-the-lookups.patch
@@ -0,0 +1,660 @@
+From a4b491c53016ae4f0aeb3aff9321ec1274f0a61c 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 7/8] libports: use a global hash table for the lookups
+
+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 global hash table for lookups instead.  Keep the per-bucket hash
+tables for efficient iteration over buckets.  Furthermore, serialize
+access to all hash tables 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 so that it
+takes a pointer to a hash table as first argument.
+(ports_bucket_iterate): Ajust call to former function accordingly.
+* libports/class-iterate.c (ports_class_iterate): Just call the
+generalized _ports_bucket_class_iterate with the global hash table as
+argument.
+* 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           | 16 +++++++++-------
+ libports/claim-right.c              |  5 ++++-
+ libports/class-iterate.c            | 10 +---------
+ libports/complete-deallocate.c      |  7 +++----
+ libports/create-bucket.c            |  6 ------
+ libports/create-class.c             |  1 -
+ libports/create-internal.c          | 19 +++++++++++++------
+ libports/destroy-right.c            |  5 +++--
+ libports/import-port.c              | 19 +++++++++++++------
+ libports/inhibit-all-rpcs.c         | 27 +++++++++++++--------------
+ libports/inhibit-bucket-rpcs.c      |  3 ++-
+ libports/inhibit-class-rpcs.c       | 27 ++++++++++++++++++---------
+ libports/init.c                     |  7 ++++++-
+ libports/lookup-port.c              | 23 +++++++++--------------
+ libports/ports.h                    | 22 +++++++++++++++++-----
+ libports/reallocate-from-external.c | 15 +++++++++++----
+ libports/reallocate-port.c          |  9 ++++++++-
+ libports/transfer-right.c           | 18 ++++++++++++++----
+ 18 files changed, 144 insertions(+), 95 deletions(-)
+
+diff --git a/libports/bucket-iterate.c b/libports/bucket-iterate.c
+index 2d1b00d..79b6d72 100644
+--- a/libports/bucket-iterate.c
++++ b/libports/bucket-iterate.c
+@@ -25,7 +25,7 @@
+ /* Internal entrypoint for both ports_bucket_iterate and ports_class_iterate.
+    If CLASS is non-null, call FUN only for ports in that class.  */
+ error_t
+-_ports_bucket_class_iterate (struct port_bucket *bucket,
++_ports_bucket_class_iterate (struct hurd_ihash *ht,
+ 			     struct port_class *class,
+ 			     error_t (*fun)(void *))
+ {
+@@ -36,23 +36,24 @@ _ports_bucket_class_iterate (struct port_bucket *bucket,
+   error_t err;
+ 
+   pthread_mutex_lock (&_ports_lock);
++  pthread_rwlock_rdlock (&_ports_htable_lock);
+ 
+-  if (bucket->htable.nr_items == 0)
++  if (ht->nr_items == 0)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
++      pthread_rwlock_unlock (&_ports_htable_lock);
+       return 0;
+     }
+ 
+-  nr_items = bucket->htable.nr_items;
++  nr_items = ht->nr_items;
+   p = malloc (nr_items * sizeof *p);
+   if (p == NULL)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
++      pthread_rwlock_unlock (&_ports_htable_lock);
+       return ENOMEM;
+     }
+ 
+   n = 0;
+-  HURD_IHASH_ITERATE (&bucket->htable, arg)
++  HURD_IHASH_ITERATE (ht, arg)
+     {
+       struct port_info *const pi = arg;
+ 
+@@ -63,6 +64,7 @@ _ports_bucket_class_iterate (struct port_bucket *bucket,
+ 	  n++;
+ 	}
+     }
++  pthread_rwlock_unlock (&_ports_htable_lock);
+   pthread_mutex_unlock (&_ports_lock);
+ 
+   if (n != 0 && n != nr_items)
+@@ -89,5 +91,5 @@ error_t
+ ports_bucket_iterate (struct port_bucket *bucket,
+ 		      error_t (*fun)(void *))
+ {
+-  return _ports_bucket_class_iterate (bucket, 0, fun);
++  return _ports_bucket_class_iterate (&bucket->htable, NULL, fun);
+ }
+diff --git a/libports/claim-right.c b/libports/claim-right.c
+index 4851ea3..85592ff 100644
+--- a/libports/claim-right.c
++++ b/libports/claim-right.c
+@@ -34,10 +34,13 @@ ports_claim_right (void *portstruct)
+   if (ret == MACH_PORT_NULL)
+     return ret;
+ 
+-  pthread_mutex_lock (&_ports_lock);
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+   hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++  pthread_rwlock_unlock (&_ports_htable_lock);
+   err = mach_port_move_member (mach_task_self (), ret, MACH_PORT_NULL);
+   assert_perror (err);
++  pthread_mutex_lock (&_ports_lock);
+   pi->port_right = MACH_PORT_NULL;
+   if (pi->flags & PORT_HAS_SENDRIGHTS)
+     {
+diff --git a/libports/class-iterate.c b/libports/class-iterate.c
+index 1f8878a..df33818 100644
+--- a/libports/class-iterate.c
++++ b/libports/class-iterate.c
+@@ -23,13 +23,5 @@ error_t
+ ports_class_iterate (struct port_class *class,
+ 		     error_t (*fun)(void *))
+ {
+-  pthread_mutex_lock (&_ports_lock);
+-  if (class->ports != 0)
+-    {
+-      struct port_bucket *bucket = class->ports->bucket;
+-      pthread_mutex_unlock (&_ports_lock);
+-      return _ports_bucket_class_iterate (bucket, class, fun);
+-    }
+-  pthread_mutex_unlock (&_ports_lock);
+-  return 0;
++  return _ports_bucket_class_iterate (&_ports_htable, class, fun);
+ }
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 8ce095b..4768dab 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -29,16 +29,15 @@ _ports_complete_deallocate (struct port_info *pi)
+ 
+   if (pi->port_right)
+     {
++      pthread_rwlock_wrlock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++      pthread_rwlock_unlock (&_ports_htable_lock);
+       mach_port_mod_refs (mach_task_self (), pi->port_right,
+ 			  MACH_PORT_RIGHT_RECEIVE, -1);
+       pi->port_right = MACH_PORT_NULL;
+     }
+ 
+-  *pi->prevp = pi->next;
+-  if (pi->next)
+-    pi->next->prevp = pi->prevp;
+-
+   pi->bucket->count--;
+   pi->class->count--;
+ 
+diff --git a/libports/create-bucket.c b/libports/create-bucket.c
+index 52d50c3..2c5f1b6 100644
+--- a/libports/create-bucket.c
++++ b/libports/create-bucket.c
+@@ -48,11 +48,5 @@ ports_create_bucket ()
+ 
+   hurd_ihash_init (&ret->htable, offsetof (struct port_info, hentry));
+   ret->rpcs = ret->flags = ret->count = 0;
+-
+-  pthread_mutex_lock (&_ports_lock);
+-  ret->next = _ports_all_buckets;
+-  _ports_all_buckets = ret;
+-  pthread_mutex_unlock (&_ports_lock);
+-
+   return ret;
+ }
+diff --git a/libports/create-class.c b/libports/create-class.c
+index 12c8add..782f52b 100644
+--- a/libports/create-class.c
++++ b/libports/create-class.c
+@@ -39,7 +39,6 @@ ports_create_class (void (*clean_routine)(void *),
+   cl->dropweak_routine = dropweak_routine;
+   cl->flags = 0;
+   cl->rpcs = 0;
+-  cl->ports = NULL;
+   cl->count = 0;
+   cl->uninhibitable_rpcs = ports_default_uninhibitable_rpcs;
+ 
+diff --git a/libports/create-internal.c b/libports/create-internal.c
+index 8551297..8543986 100644
+--- a/libports/create-internal.c
++++ b/libports/create-internal.c
+@@ -81,15 +81,22 @@ _ports_create_port_internal (struct port_class *class,
+       goto loop;
+     }
+ 
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, port, pi);
++  if (err)
++    {
++      pthread_rwlock_unlock (&_ports_htable_lock);
++      goto lose;
++    }
+   err = hurd_ihash_add (&bucket->htable, port, pi);
+   if (err)
+-    goto lose;
++    {
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
++      pthread_rwlock_unlock (&_ports_htable_lock);
++      goto lose;
++    }
++  pthread_rwlock_unlock (&_ports_htable_lock);
+ 
+-  pi->next = class->ports;
+-  pi->prevp = &class->ports;
+-  if (class->ports)
+-    class->ports->prevp = &pi->next;
+-  class->ports = pi;
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+diff --git a/libports/destroy-right.c b/libports/destroy-right.c
+index 65e19c7..448b379 100644
+--- a/libports/destroy-right.c
++++ b/libports/destroy-right.c
+@@ -30,12 +30,13 @@ ports_destroy_right (void *portstruct)
+ 
+   if (pi->port_right != MACH_PORT_NULL)
+     {
+-      pthread_mutex_lock (&_ports_lock);
++      pthread_rwlock_wrlock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++      pthread_rwlock_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..2660672 100644
+--- a/libports/import-port.c
++++ b/libports/import-port.c
+@@ -75,15 +75,22 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket,
+       goto loop;
+     }
+ 
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, port, pi);
++  if (err)
++    {
++      pthread_rwlock_unlock (&_ports_htable_lock);
++      goto lose;
++    }
+   err = hurd_ihash_add (&bucket->htable, port, pi);
+   if (err)
+-    goto lose;
++    {
++      hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
++      pthread_rwlock_unlock (&_ports_htable_lock);
++      goto lose;
++    }
++  pthread_rwlock_unlock (&_ports_htable_lock);
+ 
+-  pi->next = class->ports;
+-  pi->prevp = &class->ports;
+-  if (class->ports)
+-    class->ports->prevp = &pi->next;
+-  class->ports = pi;
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+diff --git a/libports/inhibit-all-rpcs.c b/libports/inhibit-all-rpcs.c
+index d4a54ba..27e2ec5 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_rwlock_rdlock (&_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_rwlock_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..82efdf5 100644
+--- a/libports/inhibit-bucket-rpcs.c
++++ b/libports/inhibit-bucket-rpcs.c
+@@ -35,6 +35,7 @@ ports_inhibit_bucket_rpcs (struct port_bucket *bucket)
+     {
+       int this_one = 0;
+ 
++      pthread_rwlock_rdlock (&_ports_htable_lock);
+       HURD_IHASH_ITERATE (&bucket->htable, portstruct)
+ 	{
+ 	  struct rpc_info *rpc;
+@@ -49,7 +50,7 @@ ports_inhibit_bucket_rpcs (struct port_bucket *bucket)
+ 		hurd_thread_cancel (rpc->thread);
+ 	    }
+ 	}
+-
++      pthread_rwlock_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..9a87a5f 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_rwlock_rdlock (&_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_rwlock_unlock (&_ports_htable_lock);
+ 
+       while (class->rpcs > this_one)
+ 	{
+diff --git a/libports/init.c b/libports/init.c
+index 3ef5388..4a68cb8 100644
+--- a/libports/init.c
++++ b/libports/init.c
+@@ -19,9 +19,14 @@
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+ 
+ #include "ports.h"
++#include <stddef.h>
+ 
+ pthread_mutex_t _ports_lock = PTHREAD_MUTEX_INITIALIZER;
+ pthread_cond_t _ports_block = PTHREAD_COND_INITIALIZER;
+-struct port_bucket *_ports_all_buckets;
++
++struct hurd_ihash _ports_htable =
++  HURD_IHASH_INITIALIZER (offsetof (struct port_info, ports_htable_entry));
++pthread_rwlock_t _ports_htable_lock = PTHREAD_RWLOCK_INITIALIZER;
++
+ int _ports_total_rpcs;
+ int _ports_flags;
+diff --git a/libports/lookup-port.c b/libports/lookup-port.c
+index f79f6f0..858ee11 100644
+--- a/libports/lookup-port.c
++++ b/libports/lookup-port.c
+@@ -26,27 +26,22 @@ 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_rwlock_rdlock (&_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_rwlock_unlock (&_ports_htable_lock);
+   pthread_mutex_unlock (&_ports_lock);
+-  
++
+   return pi;
+ }
+diff --git a/libports/ports.h b/libports/ports.h
+index 7f13124..6922162 100644
+--- a/libports/ports.h
++++ b/libports/ports.h
+@@ -48,7 +48,7 @@ struct port_info
+   struct rpc_info *current_rpcs;
+   struct port_bucket *bucket;
+   hurd_ihash_locp_t hentry;
+-  struct port_info *next, **prevp; /* links on port_class list */
++  hurd_ihash_locp_t ports_htable_entry;
+ };
+ typedef struct port_info *port_info_t;
+ 
+@@ -61,11 +61,12 @@ typedef struct port_info *port_info_t;
+ struct port_bucket
+ {
+   mach_port_t portset;
++  /* Per-bucket hash table used for fast iteration.  Access must be
++     serialized using _ports_htable_lock.  */
+   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 +79,6 @@ struct port_class
+ {
+   int flags;
+   int rpcs;
+-  struct port_info *ports;
+   int count;
+   void (*clean_routine) (void *);
+   void (*dropweak_routine) (void *);
+@@ -277,7 +277,7 @@ error_t ports_class_iterate (struct port_class *class,
+ 			     error_t (*fun)(void *port));
+ 
+ /* Internal entrypoint for above two.  */
+-error_t _ports_bucket_class_iterate (struct port_bucket *bucket,
++error_t _ports_bucket_class_iterate (struct hurd_ihash *ht,
+ 				     struct port_class *class,
+ 				     error_t (*fun)(void *port));
+ 
+@@ -402,7 +402,19 @@ 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 global hash table mapping port names to port_info objects.  This
++   table is used for port lookups and to iterate over classes.
++
++   A port in this hash table carries an implicit light reference.
++   When the reference counts reach zero, we call
++   _ports_complete_deallocate.  There we reacquire our lock
++   momentarily to check whether someone else reacquired a reference
++   through the hash table.  */
++extern struct hurd_ihash _ports_htable;
++/* Access to the hash table is protected by this lock.  */
++extern pthread_rwlock_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..9944b39 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -43,8 +43,11 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+ 			    MACH_PORT_RIGHT_RECEIVE, -1);
+   assert_perror (err);
+ 
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+   hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+-  
++  pthread_rwlock_unlock (&_ports_htable_lock);
++
+   if ((pi->flags & PORT_HAS_SENDRIGHTS) && !stat.mps_srights)
+     {
+       dropref = 1;
+@@ -59,11 +62,15 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+   pi->port_right = receive;
+   pi->cancel_threshold = 0;
+   pi->mscount = stat.mps_mscount;
+-  
+-  err = hurd_ihash_add (&pi->bucket->htable, receive, pi);
++
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, receive, pi);
+   assert_perror (err);
++  err = hurd_ihash_add (&pi->bucket->htable, receive, pi);
++  pthread_rwlock_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..cc534eb 100644
+--- a/libports/reallocate-port.c
++++ b/libports/reallocate-port.c
+@@ -36,7 +36,10 @@ ports_reallocate_port (void *portstruct)
+ 			    MACH_PORT_RIGHT_RECEIVE, -1);
+   assert_perror (err);
+ 
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+   hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
++  pthread_rwlock_unlock (&_ports_htable_lock);
+ 
+   err = mach_port_allocate (mach_task_self (), MACH_PORT_RIGHT_RECEIVE,
+ 			    &pi->port_right);
+@@ -48,9 +51,13 @@ ports_reallocate_port (void *portstruct)
+     }
+   pi->cancel_threshold = 0;
+   pi->mscount = 0;
+-  err = hurd_ihash_add (&pi->bucket->htable, pi->port_right, pi);
++  pthread_rwlock_wrlock (&_ports_htable_lock);
++  err = hurd_ihash_add (&_ports_htable, pi->port_right, pi);
+   assert_perror (err);
++  err = hurd_ihash_add (&pi->bucket->htable, pi->port_right, pi);
++  pthread_rwlock_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..3f48290 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -41,7 +41,10 @@ ports_transfer_right (void *tostruct,
+   port = frompi->port_right;
+   if (port != MACH_PORT_NULL)
+     {
++      pthread_rwlock_wrlock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, frompi->ports_htable_entry);
+       hurd_ihash_locp_remove (&frompi->bucket->htable, frompi->hentry);
++      pthread_rwlock_unlock (&_ports_htable_lock);
+       frompi->port_right = MACH_PORT_NULL;
+       if (frompi->flags & PORT_HAS_SENDRIGHTS)
+ 	{
+@@ -54,7 +57,10 @@ ports_transfer_right (void *tostruct,
+   /* Destroy the existing right in TOPI. */
+   if (topi->port_right != MACH_PORT_NULL)
+     {
++      pthread_rwlock_wrlock (&_ports_htable_lock);
++      hurd_ihash_locp_remove (&_ports_htable, topi->ports_htable_entry);
+       hurd_ihash_locp_remove (&topi->bucket->htable, topi->hentry);
++      pthread_rwlock_unlock (&_ports_htable_lock);
+       err = mach_port_mod_refs (mach_task_self (), topi->port_right,
+ 				MACH_PORT_RIGHT_RECEIVE, -1);
+       assert_perror (err);
+@@ -74,10 +80,16 @@ ports_transfer_right (void *tostruct,
+   topi->port_right = port;
+   topi->cancel_threshold = frompi->cancel_threshold;
+   topi->mscount = frompi->mscount;
+-  
++
++  pthread_mutex_unlock (&_ports_lock);
++
+   if (port)
+     {
++      pthread_rwlock_wrlock (&_ports_htable_lock);
++      err = hurd_ihash_add (&_ports_htable, port, topi);
++      assert_perror (err);
+       err = hurd_ihash_add (&topi->bucket->htable, port, topi);
++      pthread_rwlock_unlock (&_ports_htable_lock);
+       assert_perror (err);
+       if (topi->bucket != frompi->bucket)
+         {
+@@ -86,9 +98,7 @@ ports_transfer_right (void *tostruct,
+ 	  assert_perror (err);
+ 	}
+     }
+-  
+-  pthread_mutex_unlock (&_ports_lock);
+-  
++
+   /* Take care of any lowered reference counts. */
+   if (dereffrompi)
+     ports_port_deref (frompi);
+-- 
+2.0.0
+
diff --git a/debian/patches/0008-libports-lock-less-reference-counting-for-port_info-.patch b/debian/patches/0008-libports-lock-less-reference-counting-for-port_info-.patch
new file mode 100644
index 00000000..e1864e42
--- /dev/null
+++ b/debian/patches/0008-libports-lock-less-reference-counting-for-port_info-.patch
@@ -0,0 +1,344 @@
+From bd48fb2fa898b97fd0a9581b4e549edf7488b26b 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 8/8] libports: lock-less reference counting for port_info
+ objects
+
+* libports/ports.h (struct port_info): Use the new type.
+* libports/lookup-port.c: No need to lock _ports_lock anymore.
+* libports/bucket-iterate.c: Likewise.
+* libports/complete-deallocate.c: Check if someone reacquired a
+reference through a hash table lookup.
+* libports/create-internal.c: Use the new reference counting primitives.
+* libports/get-right.c: Likewise.
+* libports/import-port.c: Likewise.
+* libports/port-deref-weak.c: Likewise.
+* libports/port-deref.c: Likewise.
+* libports/port-ref-weak.c: Likewise.
+* libports/port-ref.c: Likewise.
+* libports/reallocate-from-external.c: Likewise.
+* libports/transfer-right.c: Likewise.
+* utils/rpctrace.c: Likewise.
+---
+ libports/bucket-iterate.c           |  4 +---
+ libports/complete-deallocate.c      | 14 ++++++++++++++
+ libports/create-internal.c          |  3 +--
+ libports/get-right.c                |  2 +-
+ libports/import-port.c              |  3 +--
+ libports/lookup-port.c              |  4 +---
+ 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, 56 insertions(+), 52 deletions(-)
+
+diff --git a/libports/bucket-iterate.c b/libports/bucket-iterate.c
+index 79b6d72..b021b99 100644
+--- a/libports/bucket-iterate.c
++++ b/libports/bucket-iterate.c
+@@ -35,7 +35,6 @@ _ports_bucket_class_iterate (struct hurd_ihash *ht,
+   size_t i, n, nr_items;
+   error_t err;
+ 
+-  pthread_mutex_lock (&_ports_lock);
+   pthread_rwlock_rdlock (&_ports_htable_lock);
+ 
+   if (ht->nr_items == 0)
+@@ -59,13 +58,12 @@ _ports_bucket_class_iterate (struct hurd_ihash *ht,
+ 
+       if (class == 0 || pi->class == class)
+ 	{
+-	  pi->refcnt++;
++	  refcounts_ref (&pi->refcounts, NULL);
+ 	  p[n] = pi;
+ 	  n++;
+ 	}
+     }
+   pthread_rwlock_unlock (&_ports_htable_lock);
+-  pthread_mutex_unlock (&_ports_lock);
+ 
+   if (n != 0 && n != nr_items)
+     {
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 4768dab..0d852f5 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -29,15 +29,29 @@ _ports_complete_deallocate (struct port_info *pi)
+ 
+   if (pi->port_right)
+     {
++      struct references result;
++
+       pthread_rwlock_wrlock (&_ports_htable_lock);
++      refcounts_references (&pi->refcounts, &result);
++      if (result.hard > 0 || result.weak > 0)
++        {
++          /* A reference was reacquired through a hash table lookup.
++             It's fine, we didn't touch anything yet. */
++          pthread_mutex_unlock (&_ports_htable_lock);
++          return;
++        }
++
+       hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+       pthread_rwlock_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 8543986..2d85931 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 2660672..c337c85 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 858ee11..cff0546 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_rwlock_rdlock (&_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_rwlock_unlock (&_ports_htable_lock);
+-  pthread_mutex_unlock (&_ports_lock);
+ 
+   return pi;
+ }
+diff --git a/libports/port-deref-weak.c b/libports/port-deref-weak.c
+index beb4842..8432660 100644
+--- a/libports/port-deref-weak.c
++++ b/libports/port-deref-weak.c
+@@ -25,12 +25,8 @@ void
+ ports_port_deref_weak (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  assert (pi->weakrefcnt);
+-  pi->weakrefcnt--;
+-  if (pi->refcnt == 0 && pi->weakrefcnt == 0)
++  struct references result;
++  refcounts_deref_weak (&pi->refcounts, &result);
++  if (result.hard == 0 && result.weak == 0)
+     _ports_complete_deallocate (pi);
+-  else
+-    pthread_mutex_unlock (&_ports_lock);
+ }
+diff --git a/libports/port-deref.c b/libports/port-deref.c
+index cf9b238..b97dd13 100644
+--- a/libports/port-deref.c
++++ b/libports/port-deref.c
+@@ -25,26 +25,24 @@ void
+ ports_port_deref (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  int trieddroppingweakrefs = 0;
+-
+- retry:
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  
+-  if (pi->refcnt == 1 && pi->weakrefcnt
+-      && pi->class->dropweak_routine && !trieddroppingweakrefs)
++  struct references result;
++
++  if (pi->class->dropweak_routine)
+     {
+-      pthread_mutex_unlock (&_ports_lock);
+-      (*pi->class->dropweak_routine) (pi);
+-      trieddroppingweakrefs = 1;
+-      goto retry;
++      /* If we need to call the dropweak routine, we need to hold one
++         reference while doing so.  We use a weak reference for this
++         purpose, which we acquire by demoting our hard reference to a
++         weak one.  */
++      refcounts_demote (&pi->refcounts, &result);
++
++      if (result.hard == 0 && result.weak > 1)
++        (*pi->class->dropweak_routine) (pi);
++
++      refcounts_deref_weak (&pi->refcounts, &result);
+     }
+-  
+-  assert (pi->refcnt);
++  else
++    refcounts_deref (&pi->refcounts, &result);
+ 
+-  pi->refcnt--;
+-  if (pi->refcnt == 0 && pi->weakrefcnt == 0)
++  if (result.hard == 0 && result.weak == 0)
+     _ports_complete_deallocate (pi);
+-  else
+-    pthread_mutex_unlock (&_ports_lock);
+ }
+diff --git a/libports/port-ref-weak.c b/libports/port-ref-weak.c
+index c7d3c69..e4b7fc8 100644
+--- a/libports/port-ref-weak.c
++++ b/libports/port-ref-weak.c
+@@ -25,9 +25,7 @@ void
+ ports_port_ref_weak (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  assert (pi->refcnt || pi->weakrefcnt);
+-  pi->weakrefcnt++;
+-  pthread_mutex_unlock (&_ports_lock);
++  struct references result;
++  refcounts_ref_weak (&pi->refcounts, &result);
++  assert (result.hard > 0 || result.weak > 1);
+ }
+diff --git a/libports/port-ref.c b/libports/port-ref.c
+index 92b7118..761c50f 100644
+--- a/libports/port-ref.c
++++ b/libports/port-ref.c
+@@ -25,9 +25,7 @@ void
+ ports_port_ref (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+-  
+-  pthread_mutex_lock (&_ports_lock);
+-  assert (pi->refcnt || pi->weakrefcnt);
+-  pi->refcnt++;
+-  pthread_mutex_unlock (&_ports_lock);
++  struct references result;
++  refcounts_ref (&pi->refcounts, &result);
++  assert (result.hard > 1 || result.weak > 0);
+ }
+diff --git a/libports/ports.h b/libports/ports.h
+index 6922162..40d3b43 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 9944b39..7205bd9 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -56,7 +56,7 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+   else if (((pi->flags & PORT_HAS_SENDRIGHTS) == 0) && stat.mps_srights)
+     {
+       pi->flags |= PORT_HAS_SENDRIGHTS;
+-      pi->refcnt++;
++      refcounts_ref (&pi->refcounts, NULL);
+     }
+   
+   pi->port_right = receive;
+diff --git a/libports/transfer-right.c b/libports/transfer-right.c
+index 3f48290..776a8d2 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -72,7 +72,7 @@ ports_transfer_right (void *tostruct,
+       else if (((topi->flags & PORT_HAS_SENDRIGHTS) == 0) && hassendrights)
+ 	{
+ 	  topi->flags |= PORT_HAS_SENDRIGHTS;
+-	  topi->refcnt++;
++	  refcounts_ref (&topi->refcounts, NULL);
+ 	}
+     }
+   
+diff --git a/utils/rpctrace.c b/utils/rpctrace.c
+index fc913e3..b11fea4 100644
+--- a/utils/rpctrace.c
++++ b/utils/rpctrace.c
+@@ -431,7 +431,9 @@ destroy_receiver_info (struct receiver_info *info)
+   while (send_wrapper)
+     {
+       struct sender_info *next = send_wrapper->next;
+-      assert (TRACED_INFO (send_wrapper)->pi.refcnt == 1);
++      assert (
++	refcounts_hard_references (&TRACED_INFO (send_wrapper)->pi.refcounts)
++	== 1);
+       /* Reset the receive_right of the send wrapper in advance to avoid
+        * destroy_receiver_info is called when the port info is destroyed. */
+       send_wrapper->receive_right = NULL;
+@@ -848,7 +850,11 @@ rewrite_right (mach_port_t *right, mach_msg_type_name_t *type,
+ 	    hurd_ihash_locp_remove (&traced_names, receiver_info->locp);
+ 
+ 	    send_wrapper2 = get_send_wrapper (receiver_info, dest, &rr);
+-	    assert (TRACED_INFO (send_wrapper2)->pi.refcnt == 1);
++	    assert (
++	      refcounts_hard_references (
++		&TRACED_INFO (send_wrapper2)->pi.refcounts)
++	      == 1);
++
+ 	    name = TRACED_INFO (send_wrapper2)->name;
+ 	    TRACED_INFO (send_wrapper2)->name = NULL;
+ 	    /* send_wrapper2 isn't destroyed normally, so we need to unlink
+-- 
+2.0.0
+
diff --git a/debian/patches/series b/debian/patches/series
index 91cedd09..4befb5dc 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -51,3 +51,11 @@ fix-net_rcv_msg.patch
 #pp.patch
 #pp-dde.patch
 #pp-random.patch
+0001-ext2fs-use-correct-type-for-disk-offsets.patch
+0002-ext2fs-use-a-seperate-lock-to-protect-nodehash.patch
+0003-fatfs-use-a-seperate-lock-to-protect-nodehash.patch
+0004-isofs-use-a-seperate-lock-to-protect-node_cache.patch
+0005-tmpfs-use-a-seperate-lock-to-protect-all_nodes.patch
+0006-libdiskfs-lock-less-reference-counting-of-nodes.patch
+0007-libports-use-a-global-hash-table-for-the-lookups.patch
+0008-libports-lock-less-reference-counting-for-port_info-.patch