Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2: (32 commits)
  [PATCH] ocfs2: zero_user_page conversion
  ocfs2: Support xfs style space reservation ioctls
  ocfs2: support for removing file regions
  ocfs2: update truncate handling of partial clusters
  ocfs2: btree support for removal of arbirtrary extents
  ocfs2: Support creation of unwritten extents
  ocfs2: support writing of unwritten extents
  ocfs2: small cleanup of ocfs2_write_begin_nolock()
  ocfs2: btree changes for unwritten extents
  ocfs2: abstract btree growing calls
  ocfs2: use all extent block suballocators
  ocfs2: plug truncate into cached dealloc routines
  ocfs2: simplify deallocation locking
  ocfs2: harden buffer check during mapping of page blocks
  ocfs2: shared writeable mmap
  ocfs2: factor out write aops into nolock variants
  ocfs2: rework ocfs2_buffered_write_cluster()
  ocfs2: take ip_alloc_sem during entire truncate
  ocfs2: Add "preferred slot" mount option
  [KJ PATCH] Replacing memset(<addr>,0,PAGE_SIZE) with clear_page() in fs/ocfs2/dlm/dlmrecovery.c
  ...

36 files changed, 4548 insertions, 1036 deletions

diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index 7b48c034b31..3b0185fdf9a 100644
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -29,10 +29,11 @@
 
 struct configfs_dirent {
 	atomic_t		s_count;
+	int			s_dependent_count;
 	struct list_head	s_sibling;
 	struct list_head	s_children;
 	struct list_head	s_links;
-	void 			* s_element;
+	void			* s_element;
 	int			s_type;
 	umode_t			s_mode;
 	struct dentry		* s_dentry;
@@ -41,8 +42,8 @@ struct configfs_dirent {
 
 #define CONFIGFS_ROOT		0x0001
 #define CONFIGFS_DIR		0x0002
-#define CONFIGFS_ITEM_ATTR 	0x0004
-#define CONFIGFS_ITEM_LINK 	0x0020
+#define CONFIGFS_ITEM_ATTR	0x0004
+#define CONFIGFS_ITEM_LINK	0x0020
 #define CONFIGFS_USET_DIR	0x0040
 #define CONFIGFS_USET_DEFAULT	0x0080
 #define CONFIGFS_USET_DROPPING	0x0100
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 5e6e37e58f3..2f436d4f1d6 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -355,6 +355,10 @@ static int configfs_detach_prep(struct dentry *dentry)
 			/* Mark that we've taken i_mutex */
 			sd->s_type |= CONFIGFS_USET_DROPPING;
 
+			/*
+			 * Yup, recursive.  If there's a problem, blame
+			 * deep nesting of default_groups
+			 */
 			ret = configfs_detach_prep(sd->s_dentry);
 			if (!ret)
 				continue;
@@ -562,7 +566,7 @@ static int populate_groups(struct config_group *group)
 
 /*
  * All of link_obj/unlink_obj/link_group/unlink_group require that
- * subsys->su_sem is held.
+ * subsys->su_mutex is held.
  */
 
 static void unlink_obj(struct config_item *item)
@@ -714,6 +718,28 @@ static void configfs_detach_group(struct config_item *item)
 }
 
 /*
+ * After the item has been detached from the filesystem view, we are
+ * ready to tear it out of the hierarchy.  Notify the client before
+ * we do that so they can perform any cleanup that requires
+ * navigating the hierarchy.  A client does not need to provide this
+ * callback.  The subsystem semaphore MUST be held by the caller, and
+ * references must be valid for both items.  It also assumes the
+ * caller has validated ci_type.
+ */
+static void client_disconnect_notify(struct config_item *parent_item,
+				     struct config_item *item)
+{
+	struct config_item_type *type;
+
+	type = parent_item->ci_type;
+	BUG_ON(!type);
+
+	if (type->ct_group_ops && type->ct_group_ops->disconnect_notify)
+		type->ct_group_ops->disconnect_notify(to_config_group(parent_item),
+						      item);
+}
+
+/*
  * Drop the initial reference from make_item()/make_group()
  * This function assumes that reference is held on item
  * and that item holds a valid reference to the parent.  Also, it
@@ -733,11 +759,244 @@ static void client_drop_item(struct config_item *parent_item,
 	 */
 	if (type->ct_group_ops && type->ct_group_ops->drop_item)
 		type->ct_group_ops->drop_item(to_config_group(parent_item),
-						item);
+					      item);
 	else
 		config_item_put(item);
 }
 
+#ifdef DEBUG
+static void configfs_dump_one(struct configfs_dirent *sd, int level)
+{
+	printk(KERN_INFO "%*s\"%s\":\n", level, " ", configfs_get_name(sd));
+
+#define type_print(_type) if (sd->s_type & _type) printk(KERN_INFO "%*s %s\n", level, " ", #_type);
+	type_print(CONFIGFS_ROOT);
+	type_print(CONFIGFS_DIR);
+	type_print(CONFIGFS_ITEM_ATTR);
+	type_print(CONFIGFS_ITEM_LINK);
+	type_print(CONFIGFS_USET_DIR);
+	type_print(CONFIGFS_USET_DEFAULT);
+	type_print(CONFIGFS_USET_DROPPING);
+#undef type_print
+}
+
+static int configfs_dump(struct configfs_dirent *sd, int level)
+{
+	struct configfs_dirent *child_sd;
+	int ret = 0;
+
+	configfs_dump_one(sd, level);
+
+	if (!(sd->s_type & (CONFIGFS_DIR|CONFIGFS_ROOT)))
+		return 0;
+
+	list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
+		ret = configfs_dump(child_sd, level + 2);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+#endif
+
+
+/*
+ * configfs_depend_item() and configfs_undepend_item()
+ *
+ * WARNING: Do not call these from a configfs callback!
+ *
+ * This describes these functions and their helpers.
+ *
+ * Allow another kernel system to depend on a config_item.  If this
+ * happens, the item cannot go away until the dependant can live without
+ * it.  The idea is to give client modules as simple an interface as
+ * possible.  When a system asks them to depend on an item, they just
+ * call configfs_depend_item().  If the item is live and the client
+ * driver is in good shape, we'll happily do the work for them.
+ *
+ * Why is the locking complex?  Because configfs uses the VFS to handle
+ * all locking, but this function is called outside the normal
+ * VFS->configfs path.  So it must take VFS locks to prevent the
+ * VFS->configfs stuff (configfs_mkdir(), configfs_rmdir(), etc).  This is
+ * why you can't call these functions underneath configfs callbacks.
+ *
+ * Note, btw, that this can be called at *any* time, even when a configfs
+ * subsystem isn't registered, or when configfs is loading or unloading.
+ * Just like configfs_register_subsystem().  So we take the same
+ * precautions.  We pin the filesystem.  We lock each i_mutex _in_order_
+ * on our way down the tree.  If we can find the target item in the
+ * configfs tree, it must be part of the subsystem tree as well, so we
+ * do not need the subsystem semaphore.  Holding the i_mutex chain locks
+ * out mkdir() and rmdir(), who might be racing us.
+ */
+
+/*
+ * configfs_depend_prep()
+ *
+ * Only subdirectories count here.  Files (CONFIGFS_NOT_PINNED) are
+ * attributes.  This is similar but not the same to configfs_detach_prep().
+ * Note that configfs_detach_prep() expects the parent to be locked when it
+ * is called, but we lock the parent *inside* configfs_depend_prep().  We
+ * do that so we can unlock it if we find nothing.
+ *
+ * Here we do a depth-first search of the dentry hierarchy looking for
+ * our object.  We take i_mutex on each step of the way down.  IT IS
+ * ESSENTIAL THAT i_mutex LOCKING IS ORDERED.  If we come back up a branch,
+ * we'll drop the i_mutex.
+ *
+ * If the target is not found, -ENOENT is bubbled up and we have released
+ * all locks.  If the target was found, the locks will be cleared by
+ * configfs_depend_rollback().
+ *
+ * This adds a requirement that all config_items be unique!
+ *
+ * This is recursive because the locking traversal is tricky.  There isn't
+ * much on the stack, though, so folks that need this function - be careful
+ * about your stack!  Patches will be accepted to make it iterative.
+ */
+static int configfs_depend_prep(struct dentry *origin,
+				struct config_item *target)
+{
+	struct configfs_dirent *child_sd, *sd = origin->d_fsdata;
+	int ret = 0;
+
+	BUG_ON(!origin || !sd);
+
+	/* Lock this guy on the way down */
+	mutex_lock(&sd->s_dentry->d_inode->i_mutex);
+	if (sd->s_element == target)  /* Boo-yah */
+		goto out;
+
+	list_for_each_entry(child_sd, &sd->s_children, s_sibling) {
+		if (child_sd->s_type & CONFIGFS_DIR) {
+			ret = configfs_depend_prep(child_sd->s_dentry,
+						   target);
+			if (!ret)
+				goto out;  /* Child path boo-yah */
+		}
+	}
+
+	/* We looped all our children and didn't find target */
+	mutex_unlock(&sd->s_dentry->d_inode->i_mutex);
+	ret = -ENOENT;
+
+out:
+	return ret;
+}
+
+/*
+ * This is ONLY called if configfs_depend_prep() did its job.  So we can
+ * trust the entire path from item back up to origin.
+ *
+ * We walk backwards from item, unlocking each i_mutex.  We finish by
+ * unlocking origin.
+ */
+static void configfs_depend_rollback(struct dentry *origin,
+				     struct config_item *item)
+{
+	struct dentry *dentry = item->ci_dentry;
+
+	while (dentry != origin) {
+		mutex_unlock(&dentry->d_inode->i_mutex);
+		dentry = dentry->d_parent;
+	}
+
+	mutex_unlock(&origin->d_inode->i_mutex);
+}
+
+int configfs_depend_item(struct configfs_subsystem *subsys,
+			 struct config_item *target)
+{
+	int ret;
+	struct configfs_dirent *p, *root_sd, *subsys_sd = NULL;
+	struct config_item *s_item = &subsys->su_group.cg_item;
+
+	/*
+	 * Pin the configfs filesystem.  This means we can safely access
+	 * the root of the configfs filesystem.
+	 */
+	ret = configfs_pin_fs();
+	if (ret)
+		return ret;
+
+	/*
+	 * Next, lock the root directory.  We're going to check that the
+	 * subsystem is really registered, and so we need to lock out
+	 * configfs_[un]register_subsystem().
+	 */
+	mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
+
+	root_sd = configfs_sb->s_root->d_fsdata;
+
+	list_for_each_entry(p, &root_sd->s_children, s_sibling) {
+		if (p->s_type & CONFIGFS_DIR) {
+			if (p->s_element == s_item) {
+				subsys_sd = p;
+				break;
+			}
+		}
+	}
+
+	if (!subsys_sd) {
+		ret = -ENOENT;
+		goto out_unlock_fs;
+	}
+
+	/* Ok, now we can trust subsys/s_item */
+
+	/* Scan the tree, locking i_mutex recursively, return 0 if found */
+	ret = configfs_depend_prep(subsys_sd->s_dentry, target);
+	if (ret)
+		goto out_unlock_fs;
+
+	/* We hold all i_mutexes from the subsystem down to the target */
+	p = target->ci_dentry->d_fsdata;
+	p->s_dependent_count += 1;
+
+	configfs_depend_rollback(subsys_sd->s_dentry, target);
+
+out_unlock_fs:
+	mutex_unlock(&configfs_sb->s_root->d_inode->i_mutex);
+
+	/*
+	 * If we succeeded, the fs is pinned via other methods.  If not,
+	 * we're done with it anyway.  So release_fs() is always right.
+	 */
+	configfs_release_fs();
+
+	return ret;
+}
+EXPORT_SYMBOL(configfs_depend_item);
+
+/*
+ * Release the dependent linkage.  This is much simpler than
+ * configfs_depend_item() because we know that that the client driver is
+ * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
+ */
+void configfs_undepend_item(struct configfs_subsystem *subsys,
+			    struct config_item *target)
+{
+	struct configfs_dirent *sd;
+
+	/*
+	 * Since we can trust everything is pinned, we just need i_mutex
+	 * on the item.
+	 */
+	mutex_lock(&target->ci_dentry->d_inode->i_mutex);
+
+	sd = target->ci_dentry->d_fsdata;
+	BUG_ON(sd->s_dependent_count < 1);
+
+	sd->s_dependent_count -= 1;
+
+	/*
+	 * After this unlock, we cannot trust the item to stay alive!
+	 * DO NOT REFERENCE item after this unlock.
+	 */
+	mutex_unlock(&target->ci_dentry->d_inode->i_mutex);
+}
+EXPORT_SYMBOL(configfs_undepend_item);
 
 static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
@@ -783,7 +1042,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
 	snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
 
-	down(&subsys->su_sem);
+	mutex_lock(&subsys->su_mutex);
 	group = NULL;
 	item = NULL;
 	if (type->ct_group_ops->make_group) {
@@ -797,7 +1056,7 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 		if (item)
 			link_obj(parent_item, item);
 	}
-	up(&subsys->su_sem);
+	mutex_unlock(&subsys->su_mutex);
 
 	kfree(name);
 	if (!item) {
@@ -841,13 +1100,16 @@ static int configfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 out_unlink:
 	if (ret) {
 		/* Tear down everything we built up */
-		down(&subsys->su_sem);
+		mutex_lock(&subsys->su_mutex);
+
+		client_disconnect_notify(parent_item, item);
 		if (group)
 			unlink_group(group);
 		else
 			unlink_obj(item);
 		client_drop_item(parent_item, item);
-		up(&subsys->su_sem);
+
+		mutex_unlock(&subsys->su_mutex);
 
 		if (module_got)
 			module_put(owner);
@@ -881,6 +1143,13 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
 	if (sd->s_type & CONFIGFS_USET_DEFAULT)
 		return -EPERM;
 
+	/*
+	 * Here's where we check for dependents.  We're protected by
+	 * i_mutex.
+	 */
+	if (sd->s_dependent_count)
+		return -EBUSY;
+
 	/* Get a working ref until we have the child */
 	parent_item = configfs_get_config_item(dentry->d_parent);
 	subsys = to_config_group(parent_item)->cg_subsys;
@@ -910,17 +1179,19 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry)
 	if (sd->s_type & CONFIGFS_USET_DIR) {
 		configfs_detach_group(item);
 
-		down(&subsys->su_sem);
+		mutex_lock(&subsys->su_mutex);
+		client_disconnect_notify(parent_item, item);
 		unlink_group(to_config_group(item));
 	} else {
 		configfs_detach_item(item);
 
-		down(&subsys->su_sem);
+		mutex_lock(&subsys->su_mutex);
+		client_disconnect_notify(parent_item, item);
 		unlink_obj(item);
 	}
 
 	client_drop_item(parent_item, item);
-	up(&subsys->su_sem);
+	mutex_unlock(&subsys->su_mutex);
 
 	/* Drop our reference from above */
 	config_item_put(item);
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index 3527c7c6def..a3658f9a082 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -27,19 +27,26 @@
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
-#include <asm/semaphore.h>
 
 #include <linux/configfs.h>
 #include "configfs_internal.h"
 
+/*
+ * A simple attribute can only be 4096 characters.  Why 4k?  Because the
+ * original code limited it to PAGE_SIZE.  That's a bad idea, though,
+ * because an attribute of 16k on ia64 won't work on x86.  So we limit to
+ * 4k, our minimum common page size.
+ */
+#define SIMPLE_ATTR_SIZE 4096
 
 struct configfs_buffer {
 	size_t			count;
 	loff_t			pos;
 	char			* page;
 	struct configfs_item_operations	* ops;
-	struct semaphore	sem;
+	struct mutex		mutex;
 	int			needs_read_fill;
 };
 
@@ -69,7 +76,7 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
 
 	count = ops->show_attribute(item,attr,buffer->page);
 	buffer->needs_read_fill = 0;
-	BUG_ON(count > (ssize_t)PAGE_SIZE);
+	BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
 	if (count >= 0)
 		buffer->count = count;
 	else
@@ -102,7 +109,7 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp
 	struct configfs_buffer * buffer = file->private_data;
 	ssize_t retval = 0;
 
-	down(&buffer->sem);
+	mutex_lock(&buffer->mutex);
 	if (buffer->needs_read_fill) {
 		if ((retval = fill_read_buffer(file->f_path.dentry,buffer)))
 			goto out;
@@ -112,7 +119,7 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp
 	retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
 					 buffer->count);
 out:
-	up(&buffer->sem);
+	mutex_unlock(&buffer->mutex);
 	return retval;
 }
 
@@ -137,8 +144,8 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size
 	if (!buffer->page)
 		return -ENOMEM;
 
-	if (count >= PAGE_SIZE)
-		count = PAGE_SIZE - 1;
+	if (count >= SIMPLE_ATTR_SIZE)
+		count = SIMPLE_ATTR_SIZE - 1;
 	error = copy_from_user(buffer->page,buf,count);
 	buffer->needs_read_fill = 1;
 	/* if buf is assumed to contain a string, terminate it by \0,
@@ -193,13 +200,13 @@ configfs_write_file(struct file *file, const char __user *buf, size_t count, lof
 	struct configfs_buffer * buffer = file->private_data;
 	ssize_t len;
 
-	down(&buffer->sem);
+	mutex_lock(&buffer->mutex);
 	len = fill_write_buffer(buffer, buf, count);
 	if (len > 0)
 		len = flush_write_buffer(file->f_path.dentry, buffer, count);
 	if (len > 0)
 		*ppos += len;
-	up(&buffer->sem);
+	mutex_unlock(&buffer->mutex);
 	return len;
 }
 
@@ -253,7 +260,7 @@ static int check_perm(struct inode * inode, struct file * file)
 		error = -ENOMEM;
 		goto Enomem;
 	}
-	init_MUTEX(&buffer->sem);
+	mutex_init(&buffer->mutex);
 	buffer->needs_read_fill = 1;
 	buffer->ops = ops;
 	file->private_data = buffer;
@@ -292,6 +299,7 @@ static int configfs_release(struct inode * inode, struct file * filp)
 	if (buffer) {
 		if (buffer->page)
 			free_page((unsigned long)buffer->page);
+		mutex_destroy(&buffer->mutex);
 		kfree(buffer);
 	}
 	return 0;
diff --git a/fs/configfs/item.c b/fs/configfs/item.c
index 24421209f85..76dc4c3e5d5 100644
--- a/fs/configfs/item.c
+++ b/fs/configfs/item.c
@@ -62,7 +62,6 @@ void config_item_init(struct config_item * item)
  *	dynamically allocated string that @item->ci_name points to.
  *	Otherwise, use the static @item->ci_namebuf array.
  */
-
 int config_item_set_name(struct config_item * item, const char * fmt, ...)
 {
 	int error = 0;
@@ -139,12 +138,7 @@ struct config_item * config_item_get(struct config_item * item)
 	return item;
 }
 
-/**
- *	config_item_cleanup - free config_item resources.
- *	@item:	item.
- */
-
-void config_item_cleanup(struct config_item * item)
+static void config_item_cleanup(struct config_item * item)
 {
 	struct config_item_type * t = item->ci_type;
 	struct config_group * s = item->ci_group;
@@ -179,39 +173,35 @@ void config_item_put(struct config_item * item)
 		kref_put(&item->ci_kref, config_item_release);
 }
 
-
 /**
  *	config_group_init - initialize a group for use
  *	@k:	group
  */
-
 void config_group_init(struct config_group *group)
 {
 	config_item_init(&group->cg_item);
 	INIT_LIST_HEAD(&group->cg_children);
 }
 
-
 /**
- *	config_group_find_obj - search for item in group.
+ *	config_group_find_item - search for item in group.
  *	@group:	group we're looking in.
  *	@name:	item's name.
  *
- *	Lock group via @group->cg_subsys, and iterate over @group->cg_list,
- *	looking for a matching config_item. If matching item is found
- *	take a reference and return the item.
+ *	Iterate over @group->cg_list, looking for a matching config_item.
+ *	If matching item is found take a reference and return the item.
+ *	Caller must have locked group via @group->cg_subsys->su_mtx.
  */
-
-struct config_item * config_group_find_obj(struct config_group * group, const char * name)
+struct config_item *config_group_find_item(struct config_group *group,
+					   const char *name)
 {
 	struct list_head * entry;
 	struct config_item * ret = NULL;
 
-        /* XXX LOCKING! */
 	list_for_each(entry,&group->cg_children) {
 		struct config_item * item = to_item(entry);
 		if (config_item_name(item) &&
-                    !strcmp(config_item_name(item), name)) {
+		    !strcmp(config_item_name(item), name)) {
 			ret = config_item_get(item);
 			break;
 		}
@@ -219,9 +209,8 @@ struct config_item * config_group_find_obj(struct config_group * group, const ch
 	return ret;
 }
 
-
 EXPORT_SYMBOL(config_item_init);
 EXPORT_SYMBOL(config_group_init);
 EXPORT_SYMBOL(config_item_get);
 EXPORT_SYMBOL(config_item_put);
-EXPORT_SYMBOL(config_group_find_obj);
+EXPORT_SYMBOL(config_group_find_item);
diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index 5069b2cb5a1..2f8e3c81bc1 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -133,14 +133,6 @@ static ssize_t cluster_set(struct cluster *cl, unsigned int *cl_field,
 	return len;
 }
 
-#define __CONFIGFS_ATTR(_name,_mode,_read,_write) {                           \
-	.attr   = { .ca_name = __stringify(_name),                            \
-		    .ca_mode = _mode,                                         \
-		    .ca_owner = THIS_MODULE },                                \
-	.show   = _read,                                                      \
-	.store  = _write,                                                     \
-}
-
 #define CLUSTER_ATTR(name, check_zero)                                        \
 static ssize_t name##_write(struct cluster *cl, const char *buf, size_t len)  \
 {                                                                             \
@@ -615,7 +607,7 @@ static struct clusters clusters_root = {
 int dlm_config_init(void)
 {
 	config_group_init(&clusters_root.subsys.su_group);
-	init_MUTEX(&clusters_root.subsys.su_sem);
+	mutex_init(&clusters_root.subsys.su_mutex);
 	return configfs_register_subsystem(&clusters_root.subsys);
 }
 
@@ -759,9 +751,9 @@ static struct space *get_space(char *name)
 	if (!space_list)
 		return NULL;
 
-	down(&space_list->cg_subsys->su_sem);
-	i = config_group_find_obj(space_list, name);
-	up(&space_list->cg_subsys->su_sem);
+	mutex_lock(&space_list->cg_subsys->su_mutex);
+	i = config_group_find_item(space_list, name);
+	mutex_unlock(&space_list->cg_subsys->su_mutex);
 
 	return to_space(i);
 }
@@ -780,7 +772,7 @@ static struct comm *get_comm(int nodeid, struct sockaddr_storage *addr)
 	if (!comm_list)
 		return NULL;
 
-	down(&clusters_root.subsys.su_sem);
+	mutex_lock(&clusters_root.subsys.su_mutex);
 
 	list_for_each_entry(i, &comm_list->cg_children, ci_entry) {
 		cm = to_comm(i);
@@ -800,7 +792,7 @@ static struct comm *get_comm(int nodeid, struct sockaddr_storage *addr)
 			break;
 		}
 	}
-	up(&clusters_root.subsys.su_sem);
+	mutex_unlock(&clusters_root.subsys.su_mutex);
 
 	if (!found)
 		cm = NULL;
diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index 19712a7d145..f5e11f4fa95 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -50,6 +50,8 @@
 #include "buffer_head_io.h"
 
 static void ocfs2_free_truncate_context(struct ocfs2_truncate_context *tc);
+static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
+					 struct ocfs2_extent_block *eb);
 
 /*
  * Structures which describe a path through a btree, and functions to
@@ -117,6 +119,31 @@ static void ocfs2_free_path(struct ocfs2_path *path)
 }
 
 /*
+ * All the elements of src into dest. After this call, src could be freed
+ * without affecting dest.
+ *
+ * Both paths should have the same root. Any non-root elements of dest
+ * will be freed.
+ */
+static void ocfs2_cp_path(struct ocfs2_path *dest, struct ocfs2_path *src)
+{
+	int i;
+
+	BUG_ON(path_root_bh(dest) != path_root_bh(src));
+	BUG_ON(path_root_el(dest) != path_root_el(src));
+
+	ocfs2_reinit_path(dest, 1);
+
+	for(i = 1; i < OCFS2_MAX_PATH_DEPTH; i++) {
+		dest->p_node[i].bh = src->p_node[i].bh;
+		dest->p_node[i].el = src->p_node[i].el;
+
+		if (dest->p_node[i].bh)
+			get_bh(dest->p_node[i].bh);
+	}
+}
+
+/*
  * Make the *dest path the same as src and re-initialize src path to
  * have a root only.
  */
@@ -212,10 +239,41 @@ out:
 	return ret;
 }
 
+/*
+ * Return the index of the extent record which contains cluster #v_cluster.
+ * -1 is returned if it was not found.
+ *
+ * Should work fine on interior and exterior nodes.
+ */
+int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster)
+{
+	int ret = -1;
+	int i;
+	struct ocfs2_extent_rec *rec;
+	u32 rec_end, rec_start, clusters;
+
+	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+		rec = &el->l_recs[i];
+
+		rec_start = le32_to_cpu(rec->e_cpos);
+		clusters = ocfs2_rec_clusters(el, rec);
+
+		rec_end = rec_start + clusters;
+
+		if (v_cluster >= rec_start && v_cluster < rec_end) {
+			ret = i;
+			break;
+		}
+	}
+
+	return ret;
+}
+
 enum ocfs2_contig_type {
 	CONTIG_NONE = 0,
 	CONTIG_LEFT,
-	CONTIG_RIGHT
+	CONTIG_RIGHT,
+	CONTIG_LEFTRIGHT,
 };
 
 
@@ -253,6 +311,14 @@ static enum ocfs2_contig_type
 {
 	u64 blkno = le64_to_cpu(insert_rec->e_blkno);
 
+	/*
+	 * Refuse to coalesce extent records with different flag
+	 * fields - we don't want to mix unwritten extents with user
+	 * data.
+	 */
+	if (ext->e_flags != insert_rec->e_flags)
+		return CONTIG_NONE;
+
 	if (ocfs2_extents_adjacent(ext, insert_rec) &&
 	    ocfs2_block_extent_contig(inode->i_sb, ext, blkno))
 			return CONTIG_RIGHT;
@@ -277,7 +343,14 @@ enum ocfs2_append_type {
 	APPEND_TAIL,
 };
 
+enum ocfs2_split_type {
+	SPLIT_NONE = 0,
+	SPLIT_LEFT,
+	SPLIT_RIGHT,
+};
+
 struct ocfs2_insert_type {
+	enum ocfs2_split_type	ins_split;
 	enum ocfs2_append_type	ins_appending;
 	enum ocfs2_contig_type	ins_contig;
 	int			ins_contig_index;
@@ -285,6 +358,13 @@ struct ocfs2_insert_type {
 	int			ins_tree_depth;
 };
 
+struct ocfs2_merge_ctxt {
+	enum ocfs2_contig_type	c_contig_type;
+	int			c_has_empty_extent;
+	int			c_split_covers_rec;
+	int			c_used_tail_recs;
+};
+
 /*
  * How many free extents have we got before we need more meta data?
  */
@@ -384,13 +464,7 @@ static int ocfs2_create_new_meta_bhs(struct ocfs2_super *osb,
 			strcpy(eb->h_signature, OCFS2_EXTENT_BLOCK_SIGNATURE);
 			eb->h_blkno = cpu_to_le64(first_blkno);
 			eb->h_fs_generation = cpu_to_le32(osb->fs_generation);
-
-#ifndef OCFS2_USE_ALL_METADATA_SUBALLOCATORS
-			/* we always use slot zero's suballocator */
-			eb->h_suballoc_slot = 0;
-#else
 			eb->h_suballoc_slot = cpu_to_le16(osb->slot_num);
-#endif
 			eb->h_suballoc_bit = cpu_to_le16(suballoc_bit_start);
 			eb->h_list.l_count =
 				cpu_to_le16(ocfs2_extent_recs_per_eb(osb->sb));
@@ -461,7 +535,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 			    struct inode *inode,
 			    struct buffer_head *fe_bh,
 			    struct buffer_head *eb_bh,
-			    struct buffer_head *last_eb_bh,
+			    struct buffer_head **last_eb_bh,
 			    struct ocfs2_alloc_context *meta_ac)
 {
 	int status, new_blocks, i;
@@ -476,7 +550,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 
 	mlog_entry_void();
 
-	BUG_ON(!last_eb_bh);
+	BUG_ON(!last_eb_bh || !*last_eb_bh);
 
 	fe = (struct ocfs2_dinode *) fe_bh->b_data;
 
@@ -507,7 +581,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 		goto bail;
 	}
 
-	eb = (struct ocfs2_extent_block *)last_eb_bh->b_data;
+	eb = (struct ocfs2_extent_block *)(*last_eb_bh)->b_data;
 	new_cpos = ocfs2_sum_rightmost_rec(&eb->h_list);
 
 	/* Note: new_eb_bhs[new_blocks - 1] is the guy which will be
@@ -568,7 +642,7 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 	 * journal_dirty erroring as it won't unless we've aborted the
 	 * handle (in which case we would never be here) so reserving
 	 * the write with journal_access is all we need to do. */
-	status = ocfs2_journal_access(handle, inode, last_eb_bh,
+	status = ocfs2_journal_access(handle, inode, *last_eb_bh,
 				      OCFS2_JOURNAL_ACCESS_WRITE);
 	if (status < 0) {
 		mlog_errno(status);
@@ -601,10 +675,10 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 	 * next_leaf on the previously last-extent-block. */
 	fe->i_last_eb_blk = cpu_to_le64(new_last_eb_blk);
 
-	eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+	eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
 	eb->h_next_leaf_blk = cpu_to_le64(new_last_eb_blk);
 
-	status = ocfs2_journal_dirty(handle, last_eb_bh);
+	status = ocfs2_journal_dirty(handle, *last_eb_bh);
 	if (status < 0)
 		mlog_errno(status);
 	status = ocfs2_journal_dirty(handle, fe_bh);
@@ -616,6 +690,14 @@ static int ocfs2_add_branch(struct ocfs2_super *osb,
 			mlog_errno(status);
 	}
 
+	/*
+	 * Some callers want to track the rightmost leaf so pass it
+	 * back here.
+	 */
+	brelse(*last_eb_bh);
+	get_bh(new_eb_bhs[0]);
+	*last_eb_bh = new_eb_bhs[0];
+
 	status = 0;
 bail:
 	if (new_eb_bhs) {
@@ -829,6 +911,87 @@ bail:
 }
 
 /*
+ * Grow a b-tree so that it has more records.
+ *
+ * We might shift the tree depth in which case existing paths should
+ * be considered invalid.
+ *
+ * Tree depth after the grow is returned via *final_depth.
+ *
+ * *last_eb_bh will be updated by ocfs2_add_branch().
+ */
+static int ocfs2_grow_tree(struct inode *inode, handle_t *handle,
+			   struct buffer_head *di_bh, int *final_depth,
+			   struct buffer_head **last_eb_bh,
+			   struct ocfs2_alloc_context *meta_ac)
+{
+	int ret, shift;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	int depth = le16_to_cpu(di->id2.i_list.l_tree_depth);
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct buffer_head *bh = NULL;
+
+	BUG_ON(meta_ac == NULL);
+
+	shift = ocfs2_find_branch_target(osb, inode, di_bh, &bh);
+	if (shift < 0) {
+		ret = shift;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/* We traveled all the way to the bottom of the allocation tree
+	 * and didn't find room for any more extents - we need to add
+	 * another tree level */
+	if (shift) {
+		BUG_ON(bh);
+		mlog(0, "need to shift tree depth (current = %d)\n", depth);
+
+		/* ocfs2_shift_tree_depth will return us a buffer with
+		 * the new extent block (so we can pass that to
+		 * ocfs2_add_branch). */
+		ret = ocfs2_shift_tree_depth(osb, handle, inode, di_bh,
+					     meta_ac, &bh);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+		depth++;
+		if (depth == 1) {
+			/*
+			 * Special case: we have room now if we shifted from
+			 * tree_depth 0, so no more work needs to be done.
+			 *
+			 * We won't be calling add_branch, so pass
+			 * back *last_eb_bh as the new leaf. At depth
+			 * zero, it should always be null so there's
+			 * no reason to brelse.
+			 */
+			BUG_ON(*last_eb_bh);
+			get_bh(bh);
+			*last_eb_bh = bh;
+			goto out;
+		}
+	}
+
+	/* call ocfs2_add_branch to add the final part of the tree with
+	 * the new data. */
+	mlog(0, "add branch. bh = %p\n", bh);
+	ret = ocfs2_add_branch(osb, handle, inode, di_bh, bh, last_eb_bh,
+			       meta_ac);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+out:
+	if (final_depth)
+		*final_depth = depth;
+	brelse(bh);
+	return ret;
+}
+
+/*
  * This is only valid for leaf nodes, which are the only ones that can
  * have empty extents anyway.
  */
@@ -934,6 +1097,22 @@ static void ocfs2_rotate_leaf(struct ocfs2_extent_list *el,
 
 }
 
+static void ocfs2_remove_empty_extent(struct ocfs2_extent_list *el)
+{
+	int size, num_recs = le16_to_cpu(el->l_next_free_rec);
+
+	BUG_ON(num_recs == 0);
+
+	if (ocfs2_is_empty_extent(&el->l_recs[0])) {
+		num_recs--;
+		size = num_recs * sizeof(struct ocfs2_extent_rec);
+		memmove(&el->l_recs[0], &el->l_recs[1], size);
+		memset(&el->l_recs[num_recs], 0,
+		       sizeof(struct ocfs2_extent_rec));
+		el->l_next_free_rec = cpu_to_le16(num_recs);
+	}
+}
+
 /*
  * Create an empty extent record .
  *
@@ -1211,6 +1390,10 @@ static void ocfs2_adjust_adjacent_records(struct ocfs2_extent_rec *left_rec,
 	 * immediately to their right.
 	 */
 	left_clusters = le32_to_cpu(right_child_el->l_recs[0].e_cpos);
+	if (ocfs2_is_empty_extent(&right_child_el->l_recs[0])) {
+		BUG_ON(le16_to_cpu(right_child_el->l_next_free_rec) <= 1);
+		left_clusters = le32_to_cpu(right_child_el->l_recs[1].e_cpos);
+	}
 	left_clusters -= le32_to_cpu(left_rec->e_cpos);
 	left_rec->e_int_clusters = cpu_to_le32(left_clusters);
 
@@ -1531,10 +1714,16 @@ out:
 	return ret;
 }
 
+/*
+ * Extend the transaction by enough credits to complete the rotation,
+ * and still leave at least the original number of credits allocated
+ * to this transaction.
+ */
 static int ocfs2_extend_rotate_transaction(handle_t *handle, int subtree_depth,
+					   int op_credits,
 					   struct ocfs2_path *path)
 {
-	int credits = (path->p_tree_depth - subtree_depth) * 2 + 1;
+	int credits = (path->p_tree_depth - subtree_depth) * 2 + 1 + op_credits;
 
 	if (handle->h_buffer_credits < credits)
 		return ocfs2_extend_trans(handle, credits);
@@ -1568,6 +1757,29 @@ static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
 	return 0;
 }
 
+static int ocfs2_leftmost_rec_contains(struct ocfs2_extent_list *el, u32 cpos)
+{
+	int next_free = le16_to_cpu(el->l_next_free_rec);
+	unsigned int range;
+	struct ocfs2_extent_rec *rec;
+
+	if (next_free == 0)
+		return 0;
+
+	rec = &el->l_recs[0];
+	if (ocfs2_is_empty_extent(rec)) {
+		/* Empty list. */
+		if (next_free == 1)
+			return 0;
+		rec = &el->l_recs[1];
+	}
+
+	range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+	if (cpos >= le32_to_cpu(rec->e_cpos) && cpos < range)
+		return 1;
+	return 0;
+}
+
 /*
  * Rotate all the records in a btree right one record, starting at insert_cpos.
  *
@@ -1586,11 +1798,12 @@ static int ocfs2_rotate_requires_path_adjustment(struct ocfs2_path *left_path,
  */
 static int ocfs2_rotate_tree_right(struct inode *inode,
 				   handle_t *handle,
+				   enum ocfs2_split_type split,
 				   u32 insert_cpos,
 				   struct ocfs2_path *right_path,
 				   struct ocfs2_path **ret_left_path)
 {
-	int ret, start;
+	int ret, start, orig_credits = handle->h_buffer_credits;
 	u32 cpos;
 	struct ocfs2_path *left_path = NULL;
 
@@ -1657,9 +1870,9 @@ static int ocfs2_rotate_tree_right(struct inode *inode,
 				(unsigned long long)
 				path_leaf_bh(left_path)->b_blocknr);
 
-		if (ocfs2_rotate_requires_path_adjustment(left_path,
+		if (split == SPLIT_NONE &&
+		    ocfs2_rotate_requires_path_adjustment(left_path,
 							  insert_cpos)) {
-			mlog(0, "Path adjustment required\n");
 
 			/*
 			 * We've rotated the tree as much as we
@@ -1687,7 +1900,7 @@ static int ocfs2_rotate_tree_right(struct inode *inode,
 		     right_path->p_tree_depth);
 
 		ret = ocfs2_extend_rotate_transaction(handle, start,
-						      right_path);
+						      orig_credits, right_path);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;
@@ -1700,6 +1913,24 @@ static int ocfs2_rotate_tree_right(struct inode *inode,
 			goto out;
 		}
 
+		if (split != SPLIT_NONE &&
+		    ocfs2_leftmost_rec_contains(path_leaf_el(right_path),
+						insert_cpos)) {
+			/*
+			 * A rotate moves the rightmost left leaf
+			 * record over to the leftmost right leaf
+			 * slot. If we're doing an extent split
+			 * instead of a real insert, then we have to
+			 * check that the extent to be split wasn't
+			 * just moved over. If it was, then we can
+			 * exit here, passing left_path back -
+			 * ocfs2_split_extent() is smart enough to
+			 * search both leaves.
+			 */
+			*ret_left_path = left_path;
+			goto out_ret_path;
+		}
+
 		/*
 		 * There is no need to re-read the next right path
 		 * as we know that it'll be our current left
@@ -1722,6 +1953,1031 @@ out_ret_path:
 	return ret;
 }
 
+static void ocfs2_update_edge_lengths(struct inode *inode, handle_t *handle,
+				      struct ocfs2_path *path)
+{
+	int i, idx;
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_block *eb;
+	u32 range;
+
+	/* Path should always be rightmost. */
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+	BUG_ON(eb->h_next_leaf_blk != 0ULL);
+
+	el = &eb->h_list;
+	BUG_ON(le16_to_cpu(el->l_next_free_rec) == 0);
+	idx = le16_to_cpu(el->l_next_free_rec) - 1;
+	rec = &el->l_recs[idx];
+	range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+
+	for (i = 0; i < path->p_tree_depth; i++) {
+		el = path->p_node[i].el;
+		idx = le16_to_cpu(el->l_next_free_rec) - 1;
+		rec = &el->l_recs[idx];
+
+		rec->e_int_clusters = cpu_to_le32(range);
+		le32_add_cpu(&rec->e_int_clusters, -le32_to_cpu(rec->e_cpos));
+
+		ocfs2_journal_dirty(handle, path->p_node[i].bh);
+	}
+}
+
+static void ocfs2_unlink_path(struct inode *inode, handle_t *handle,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc,
+			      struct ocfs2_path *path, int unlink_start)
+{
+	int ret, i;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+	struct buffer_head *bh;
+
+	for(i = unlink_start; i < path_num_items(path); i++) {
+		bh = path->p_node[i].bh;
+
+		eb = (struct ocfs2_extent_block *)bh->b_data;
+		/*
+		 * Not all nodes might have had their final count
+		 * decremented by the caller - handle this here.
+		 */
+		el = &eb->h_list;
+		if (le16_to_cpu(el->l_next_free_rec) > 1) {
+			mlog(ML_ERROR,
+			     "Inode %llu, attempted to remove extent block "
+			     "%llu with %u records\n",
+			     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+			     (unsigned long long)le64_to_cpu(eb->h_blkno),
+			     le16_to_cpu(el->l_next_free_rec));
+
+			ocfs2_journal_dirty(handle, bh);
+			ocfs2_remove_from_cache(inode, bh);
+			continue;
+		}
+
+		el->l_next_free_rec = 0;
+		memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+
+		ocfs2_journal_dirty(handle, bh);
+
+		ret = ocfs2_cache_extent_block_free(dealloc, eb);
+		if (ret)
+			mlog_errno(ret);
+
+		ocfs2_remove_from_cache(inode, bh);
+	}
+}
+
+static void ocfs2_unlink_subtree(struct inode *inode, handle_t *handle,
+				 struct ocfs2_path *left_path,
+				 struct ocfs2_path *right_path,
+				 int subtree_index,
+				 struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int i;
+	struct buffer_head *root_bh = left_path->p_node[subtree_index].bh;
+	struct ocfs2_extent_list *root_el = left_path->p_node[subtree_index].el;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_block *eb;
+
+	el = path_leaf_el(left_path);
+
+	eb = (struct ocfs2_extent_block *)right_path->p_node[subtree_index + 1].bh->b_data;
+
+	for(i = 1; i < le16_to_cpu(root_el->l_next_free_rec); i++)
+		if (root_el->l_recs[i].e_blkno == eb->h_blkno)
+			break;
+
+	BUG_ON(i >= le16_to_cpu(root_el->l_next_free_rec));
+
+	memset(&root_el->l_recs[i], 0, sizeof(struct ocfs2_extent_rec));
+	le16_add_cpu(&root_el->l_next_free_rec, -1);
+
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+	eb->h_next_leaf_blk = 0;
+
+	ocfs2_journal_dirty(handle, root_bh);
+	ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+
+	ocfs2_unlink_path(inode, handle, dealloc, right_path,
+			  subtree_index + 1);
+}
+
+static int ocfs2_rotate_subtree_left(struct inode *inode, handle_t *handle,
+				     struct ocfs2_path *left_path,
+				     struct ocfs2_path *right_path,
+				     int subtree_index,
+				     struct ocfs2_cached_dealloc_ctxt *dealloc,
+				     int *deleted)
+{
+	int ret, i, del_right_subtree = 0, right_has_empty = 0;
+	struct buffer_head *root_bh, *di_bh = path_root_bh(right_path);
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct ocfs2_extent_list *right_leaf_el, *left_leaf_el;
+	struct ocfs2_extent_block *eb;
+
+	*deleted = 0;
+
+	right_leaf_el = path_leaf_el(right_path);
+	left_leaf_el = path_leaf_el(left_path);
+	root_bh = left_path->p_node[subtree_index].bh;
+	BUG_ON(root_bh != right_path->p_node[subtree_index].bh);
+
+	if (!ocfs2_is_empty_extent(&left_leaf_el->l_recs[0]))
+		return 0;
+
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(right_path)->b_data;
+	if (ocfs2_is_empty_extent(&right_leaf_el->l_recs[0])) {
+		/*
+		 * It's legal for us to proceed if the right leaf is
+		 * the rightmost one and it has an empty extent. There
+		 * are two cases to handle - whether the leaf will be
+		 * empty after removal or not. If the leaf isn't empty
+		 * then just remove the empty extent up front. The
+		 * next block will handle empty leaves by flagging
+		 * them for unlink.
+		 *
+		 * Non rightmost leaves will throw -EAGAIN and the
+		 * caller can manually move the subtree and retry.
+		 */
+
+		if (eb->h_next_leaf_blk != 0ULL)
+			return -EAGAIN;
+
+		if (le16_to_cpu(right_leaf_el->l_next_free_rec) > 1) {
+			ret = ocfs2_journal_access(handle, inode,
+						   path_leaf_bh(right_path),
+						   OCFS2_JOURNAL_ACCESS_WRITE);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ocfs2_remove_empty_extent(right_leaf_el);
+		} else
+			right_has_empty = 1;
+	}
+
+	if (eb->h_next_leaf_blk == 0ULL &&
+	    le16_to_cpu(right_leaf_el->l_next_free_rec) == 1) {
+		/*
+		 * We have to update i_last_eb_blk during the meta
+		 * data delete.
+		 */
+		ret = ocfs2_journal_access(handle, inode, di_bh,
+					   OCFS2_JOURNAL_ACCESS_WRITE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		del_right_subtree = 1;
+	}
+
+	/*
+	 * Getting here with an empty extent in the right path implies
+	 * that it's the rightmost path and will be deleted.
+	 */
+	BUG_ON(right_has_empty && !del_right_subtree);
+
+	ret = ocfs2_journal_access(handle, inode, root_bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	for(i = subtree_index + 1; i < path_num_items(right_path); i++) {
+		ret = ocfs2_journal_access(handle, inode,
+					   right_path->p_node[i].bh,
+					   OCFS2_JOURNAL_ACCESS_WRITE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_journal_access(handle, inode,
+					   left_path->p_node[i].bh,
+					   OCFS2_JOURNAL_ACCESS_WRITE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	if (!right_has_empty) {
+		/*
+		 * Only do this if we're moving a real
+		 * record. Otherwise, the action is delayed until
+		 * after removal of the right path in which case we
+		 * can do a simple shift to remove the empty extent.
+		 */
+		ocfs2_rotate_leaf(left_leaf_el, &right_leaf_el->l_recs[0]);
+		memset(&right_leaf_el->l_recs[0], 0,
+		       sizeof(struct ocfs2_extent_rec));
+	}
+	if (eb->h_next_leaf_blk == 0ULL) {
+		/*
+		 * Move recs over to get rid of empty extent, decrease
+		 * next_free. This is allowed to remove the last
+		 * extent in our leaf (setting l_next_free_rec to
+		 * zero) - the delete code below won't care.
+		 */
+		ocfs2_remove_empty_extent(right_leaf_el);
+	}
+
+	ret = ocfs2_journal_dirty(handle, path_leaf_bh(left_path));
+	if (ret)
+		mlog_errno(ret);
+	ret = ocfs2_journal_dirty(handle, path_leaf_bh(right_path));
+	if (ret)
+		mlog_errno(ret);
+
+	if (del_right_subtree) {
+		ocfs2_unlink_subtree(inode, handle, left_path, right_path,
+				     subtree_index, dealloc);
+		ocfs2_update_edge_lengths(inode, handle, left_path);
+
+		eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+		di->i_last_eb_blk = eb->h_blkno;
+
+		/*
+		 * Removal of the extent in the left leaf was skipped
+		 * above so we could delete the right path
+		 * 1st.
+		 */
+		if (right_has_empty)
+			ocfs2_remove_empty_extent(left_leaf_el);
+
+		ret = ocfs2_journal_dirty(handle, di_bh);
+		if (ret)
+			mlog_errno(ret);
+
+		*deleted = 1;
+	} else
+		ocfs2_complete_edge_insert(inode, handle, left_path, right_path,
+					   subtree_index);
+
+out:
+	return ret;
+}
+
+/*
+ * Given a full path, determine what cpos value would return us a path
+ * containing the leaf immediately to the right of the current one.
+ *
+ * Will return zero if the path passed in is already the rightmost path.
+ *
+ * This looks similar, but is subtly different to
+ * ocfs2_find_cpos_for_left_leaf().
+ */
+static int ocfs2_find_cpos_for_right_leaf(struct super_block *sb,
+					  struct ocfs2_path *path, u32 *cpos)
+{
+	int i, j, ret = 0;
+	u64 blkno;
+	struct ocfs2_extent_list *el;
+
+	*cpos = 0;
+
+	if (path->p_tree_depth == 0)
+		return 0;
+
+	blkno = path_leaf_bh(path)->b_blocknr;
+
+	/* Start at the tree node just above the leaf and work our way up. */
+	i = path->p_tree_depth - 1;
+	while (i >= 0) {
+		int next_free;
+
+		el = path->p_node[i].el;
+
+		/*
+		 * Find the extent record just after the one in our
+		 * path.
+		 */
+		next_free = le16_to_cpu(el->l_next_free_rec);
+		for(j = 0; j < le16_to_cpu(el->l_next_free_rec); j++) {
+			if (le64_to_cpu(el->l_recs[j].e_blkno) == blkno) {
+				if (j == (next_free - 1)) {
+					if (i == 0) {
+						/*
+						 * We've determined that the
+						 * path specified is already
+						 * the rightmost one - return a
+						 * cpos of zero.
+						 */
+						goto out;
+					}
+					/*
+					 * The rightmost record points to our
+					 * leaf - we need to travel up the
+					 * tree one level.
+					 */
+					goto next_node;
+				}
+
+				*cpos = le32_to_cpu(el->l_recs[j + 1].e_cpos);
+				goto out;
+			}
+		}
+
+		/*
+		 * If we got here, we never found a valid node where
+		 * the tree indicated one should be.
+		 */
+		ocfs2_error(sb,
+			    "Invalid extent tree at extent block %llu\n",
+			    (unsigned long long)blkno);
+		ret = -EROFS;
+		goto out;
+
+next_node:
+		blkno = path->p_node[i].bh->b_blocknr;
+		i--;
+	}
+
+out:
+	return ret;
+}
+
+static int ocfs2_rotate_rightmost_leaf_left(struct inode *inode,
+					    handle_t *handle,
+					    struct buffer_head *bh,
+					    struct ocfs2_extent_list *el)
+{
+	int ret;
+
+	if (!ocfs2_is_empty_extent(&el->l_recs[0]))
+		return 0;
+
+	ret = ocfs2_journal_access(handle, inode, bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_remove_empty_extent(el);
+
+	ret = ocfs2_journal_dirty(handle, bh);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	return ret;
+}
+
+static int __ocfs2_rotate_tree_left(struct inode *inode,
+				    handle_t *handle, int orig_credits,
+				    struct ocfs2_path *path,
+				    struct ocfs2_cached_dealloc_ctxt *dealloc,
+				    struct ocfs2_path **empty_extent_path)
+{
+	int ret, subtree_root, deleted;
+	u32 right_cpos;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_path *right_path = NULL;
+
+	BUG_ON(!ocfs2_is_empty_extent(&(path_leaf_el(path)->l_recs[0])));
+
+	*empty_extent_path = NULL;
+
+	ret = ocfs2_find_cpos_for_right_leaf(inode->i_sb, path,
+					     &right_cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	left_path = ocfs2_new_path(path_root_bh(path),
+				   path_root_el(path));
+	if (!left_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ocfs2_cp_path(left_path, path);
+
+	right_path = ocfs2_new_path(path_root_bh(path),
+				    path_root_el(path));
+	if (!right_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	while (right_cpos) {
+		ret = ocfs2_find_path(inode, right_path, right_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		subtree_root = ocfs2_find_subtree_root(inode, left_path,
+						       right_path);
+
+		mlog(0, "Subtree root at index %d (blk %llu, depth %d)\n",
+		     subtree_root,
+		     (unsigned long long)
+		     right_path->p_node[subtree_root].bh->b_blocknr,
+		     right_path->p_tree_depth);
+
+		ret = ocfs2_extend_rotate_transaction(handle, subtree_root,
+						      orig_credits, left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_rotate_subtree_left(inode, handle, left_path,
+						right_path, subtree_root,
+						dealloc, &deleted);
+		if (ret == -EAGAIN) {
+			/*
+			 * The rotation has to temporarily stop due to
+			 * the right subtree having an empty
+			 * extent. Pass it back to the caller for a
+			 * fixup.
+			 */
+			*empty_extent_path = right_path;
+			right_path = NULL;
+			goto out;
+		}
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * The subtree rotate might have removed records on
+		 * the rightmost edge. If so, then rotation is
+		 * complete.
+		 */
+		if (deleted)
+			break;
+
+		ocfs2_mv_path(left_path, right_path);
+
+		ret = ocfs2_find_cpos_for_right_leaf(inode->i_sb, left_path,
+						     &right_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+out:
+	ocfs2_free_path(right_path);
+	ocfs2_free_path(left_path);
+
+	return ret;
+}
+
+static int ocfs2_remove_rightmost_path(struct inode *inode, handle_t *handle,
+				       struct ocfs2_path *path,
+				       struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret, subtree_index;
+	u32 cpos;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_dinode *di;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+
+	/*
+	 * XXX: This code assumes that the root is an inode, which is
+	 * true for now but may change as tree code gets generic.
+	 */
+	di = (struct ocfs2_dinode *)path_root_bh(path)->b_data;
+	if (!OCFS2_IS_VALID_DINODE(di)) {
+		ret = -EIO;
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has invalid path root",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno);
+		goto out;
+	}
+
+	/*
+	 * There's two ways we handle this depending on
+	 * whether path is the only existing one.
+	 */
+	ret = ocfs2_extend_rotate_transaction(handle, 0,
+					      handle->h_buffer_credits,
+					      path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_path(inode, handle, path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb, path, &cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (cpos) {
+		/*
+		 * We have a path to the left of this one - it needs
+		 * an update too.
+		 */
+		left_path = ocfs2_new_path(path_root_bh(path),
+					   path_root_el(path));
+		if (!left_path) {
+			ret = -ENOMEM;
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_find_path(inode, left_path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ret = ocfs2_journal_access_path(inode, handle, left_path);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		subtree_index = ocfs2_find_subtree_root(inode, left_path, path);
+
+		ocfs2_unlink_subtree(inode, handle, left_path, path,
+				     subtree_index, dealloc);
+		ocfs2_update_edge_lengths(inode, handle, left_path);
+
+		eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
+		di->i_last_eb_blk = eb->h_blkno;
+	} else {
+		/*
+		 * 'path' is also the leftmost path which
+		 * means it must be the only one. This gets
+		 * handled differently because we want to
+		 * revert the inode back to having extents
+		 * in-line.
+		 */
+		ocfs2_unlink_path(inode, handle, dealloc, path, 1);
+
+		el = &di->id2.i_list;
+		el->l_tree_depth = 0;
+		el->l_next_free_rec = 0;
+		memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+
+		di->i_last_eb_blk = 0;
+	}
+
+	ocfs2_journal_dirty(handle, path_root_bh(path));
+
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+}
+
+/*
+ * Left rotation of btree records.
+ *
+ * In many ways, this is (unsurprisingly) the opposite of right
+ * rotation. We start at some non-rightmost path containing an empty
+ * extent in the leaf block. The code works its way to the rightmost
+ * path by rotating records to the left in every subtree.
+ *
+ * This is used by any code which reduces the number of extent records
+ * in a leaf. After removal, an empty record should be placed in the
+ * leftmost list position.
+ *
+ * This won't handle a length update of the rightmost path records if
+ * the rightmost tree leaf record is removed so the caller is
+ * responsible for detecting and correcting that.
+ */
+static int ocfs2_rotate_tree_left(struct inode *inode, handle_t *handle,
+				  struct ocfs2_path *path,
+				  struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret, orig_credits = handle->h_buffer_credits;
+	struct ocfs2_path *tmp_path = NULL, *restart_path = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+
+	el = path_leaf_el(path);
+	if (!ocfs2_is_empty_extent(&el->l_recs[0]))
+		return 0;
+
+	if (path->p_tree_depth == 0) {
+rightmost_no_delete:
+		/*
+		 * In-inode extents. This is trivially handled, so do
+		 * it up front.
+		 */
+		ret = ocfs2_rotate_rightmost_leaf_left(inode, handle,
+						       path_leaf_bh(path),
+						       path_leaf_el(path));
+		if (ret)
+			mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Handle rightmost branch now. There's several cases:
+	 *  1) simple rotation leaving records in there. That's trivial.
+	 *  2) rotation requiring a branch delete - there's no more
+	 *     records left. Two cases of this:
+	 *     a) There are branches to the left.
+	 *     b) This is also the leftmost (the only) branch.
+	 *
+	 *  1) is handled via ocfs2_rotate_rightmost_leaf_left()
+	 *  2a) we need the left branch so that we can update it with the unlink
+	 *  2b) we need to bring the inode back to inline extents.
+	 */
+
+	eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+	el = &eb->h_list;
+	if (eb->h_next_leaf_blk == 0) {
+		/*
+		 * This gets a bit tricky if we're going to delete the
+		 * rightmost path. Get the other cases out of the way
+		 * 1st.
+		 */
+		if (le16_to_cpu(el->l_next_free_rec) > 1)
+			goto rightmost_no_delete;
+
+		if (le16_to_cpu(el->l_next_free_rec) == 0) {
+			ret = -EIO;
+			ocfs2_error(inode->i_sb,
+				    "Inode %llu has empty extent block at %llu",
+				    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+				    (unsigned long long)le64_to_cpu(eb->h_blkno));
+			goto out;
+		}
+
+		/*
+		 * XXX: The caller can not trust "path" any more after
+		 * this as it will have been deleted. What do we do?
+		 *
+		 * In theory the rotate-for-merge code will never get
+		 * here because it'll always ask for a rotate in a
+		 * nonempty list.
+		 */
+
+		ret = ocfs2_remove_rightmost_path(inode, handle, path,
+						  dealloc);
+		if (ret)
+			mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * Now we can loop, remembering the path we get from -EAGAIN
+	 * and restarting from there.
+	 */
+try_rotate:
+	ret = __ocfs2_rotate_tree_left(inode, handle, orig_credits, path,
+				       dealloc, &restart_path);
+	if (ret && ret != -EAGAIN) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	while (ret == -EAGAIN) {
+		tmp_path = restart_path;
+		restart_path = NULL;
+
+		ret = __ocfs2_rotate_tree_left(inode, handle, orig_credits,
+					       tmp_path, dealloc,
+					       &restart_path);
+		if (ret && ret != -EAGAIN) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		ocfs2_free_path(tmp_path);
+		tmp_path = NULL;
+
+		if (ret == 0)
+			goto try_rotate;
+	}
+
+out:
+	ocfs2_free_path(tmp_path);
+	ocfs2_free_path(restart_path);
+	return ret;
+}
+
+static void ocfs2_cleanup_merge(struct ocfs2_extent_list *el,
+				int index)
+{
+	struct ocfs2_extent_rec *rec = &el->l_recs[index];
+	unsigned int size;
+
+	if (rec->e_leaf_clusters == 0) {
+		/*
+		 * We consumed all of the merged-from record. An empty
+		 * extent cannot exist anywhere but the 1st array
+		 * position, so move things over if the merged-from
+		 * record doesn't occupy that position.
+		 *
+		 * This creates a new empty extent so the caller
+		 * should be smart enough to have removed any existing
+		 * ones.
+		 */
+		if (index > 0) {
+			BUG_ON(ocfs2_is_empty_extent(&el->l_recs[0]));
+			size = index * sizeof(struct ocfs2_extent_rec);
+			memmove(&el->l_recs[1], &el->l_recs[0], size);
+		}
+
+		/*
+		 * Always memset - the caller doesn't check whether it
+		 * created an empty extent, so there could be junk in
+		 * the other fields.
+		 */
+		memset(&el->l_recs[0], 0, sizeof(struct ocfs2_extent_rec));
+	}
+}
+
+/*
+ * Remove split_rec clusters from the record at index and merge them
+ * onto the beginning of the record at index + 1.
+ */
+static int ocfs2_merge_rec_right(struct inode *inode, struct buffer_head *bh,
+				handle_t *handle,
+				struct ocfs2_extent_rec *split_rec,
+				struct ocfs2_extent_list *el, int index)
+{
+	int ret;
+	unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
+	struct ocfs2_extent_rec *left_rec;
+	struct ocfs2_extent_rec *right_rec;
+
+	BUG_ON(index >= le16_to_cpu(el->l_next_free_rec));
+
+	left_rec = &el->l_recs[index];
+	right_rec = &el->l_recs[index + 1];
+
+	ret = ocfs2_journal_access(handle, inode, bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	le16_add_cpu(&left_rec->e_leaf_clusters, -split_clusters);
+
+	le32_add_cpu(&right_rec->e_cpos, -split_clusters);
+	le64_add_cpu(&right_rec->e_blkno,
+		     -ocfs2_clusters_to_blocks(inode->i_sb, split_clusters));
+	le16_add_cpu(&right_rec->e_leaf_clusters, split_clusters);
+
+	ocfs2_cleanup_merge(el, index);
+
+	ret = ocfs2_journal_dirty(handle, bh);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	return ret;
+}
+
+/*
+ * Remove split_rec clusters from the record at index and merge them
+ * onto the tail of the record at index - 1.
+ */
+static int ocfs2_merge_rec_left(struct inode *inode, struct buffer_head *bh,
+				handle_t *handle,
+				struct ocfs2_extent_rec *split_rec,
+				struct ocfs2_extent_list *el, int index)
+{
+	int ret, has_empty_extent = 0;
+	unsigned int split_clusters = le16_to_cpu(split_rec->e_leaf_clusters);
+	struct ocfs2_extent_rec *left_rec;
+	struct ocfs2_extent_rec *right_rec;
+
+	BUG_ON(index <= 0);
+
+	left_rec = &el->l_recs[index - 1];
+	right_rec = &el->l_recs[index];
+	if (ocfs2_is_empty_extent(&el->l_recs[0]))
+		has_empty_extent = 1;
+
+	ret = ocfs2_journal_access(handle, inode, bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (has_empty_extent && index == 1) {
+		/*
+		 * The easy case - we can just plop the record right in.
+		 */
+		*left_rec = *split_rec;
+
+		has_empty_extent = 0;
+	} else {
+		le16_add_cpu(&left_rec->e_leaf_clusters, split_clusters);
+	}
+
+	le32_add_cpu(&right_rec->e_cpos, split_clusters);
+	le64_add_cpu(&right_rec->e_blkno,
+		     ocfs2_clusters_to_blocks(inode->i_sb, split_clusters));
+	le16_add_cpu(&right_rec->e_leaf_clusters, -split_clusters);
+
+	ocfs2_cleanup_merge(el, index);
+
+	ret = ocfs2_journal_dirty(handle, bh);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	return ret;
+}
+
+static int ocfs2_try_to_merge_extent(struct inode *inode,
+				     handle_t *handle,
+				     struct ocfs2_path *left_path,
+				     int split_index,
+				     struct ocfs2_extent_rec *split_rec,
+				     struct ocfs2_cached_dealloc_ctxt *dealloc,
+				     struct ocfs2_merge_ctxt *ctxt)
+
+{
+	int ret = 0, delete_tail_recs = 0;
+	struct ocfs2_extent_list *el = path_leaf_el(left_path);
+	struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
+
+	BUG_ON(ctxt->c_contig_type == CONTIG_NONE);
+
+	if (ctxt->c_split_covers_rec) {
+		delete_tail_recs++;
+
+		if (ctxt->c_contig_type == CONTIG_LEFTRIGHT ||
+		    ctxt->c_has_empty_extent)
+			delete_tail_recs++;
+
+		if (ctxt->c_has_empty_extent) {
+			/*
+			 * The merge code will need to create an empty
+			 * extent to take the place of the newly
+			 * emptied slot. Remove any pre-existing empty
+			 * extents - having more than one in a leaf is
+			 * illegal.
+			 */
+			ret = ocfs2_rotate_tree_left(inode, handle, left_path,
+						     dealloc);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+			split_index--;
+			rec = &el->l_recs[split_index];
+		}
+	}
+
+	if (ctxt->c_contig_type == CONTIG_LEFTRIGHT) {
+		/*
+		 * Left-right contig implies this.
+		 */
+		BUG_ON(!ctxt->c_split_covers_rec);
+		BUG_ON(split_index == 0);
+
+		/*
+		 * Since the leftright insert always covers the entire
+		 * extent, this call will delete the insert record
+		 * entirely, resulting in an empty extent record added to
+		 * the extent block.
+		 *
+		 * Since the adding of an empty extent shifts
+		 * everything back to the right, there's no need to
+		 * update split_index here.
+		 */
+		ret = ocfs2_merge_rec_left(inode, path_leaf_bh(left_path),
+					   handle, split_rec, el, split_index);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * We can only get this from logic error above.
+		 */
+		BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
+
+		/*
+		 * The left merge left us with an empty extent, remove
+		 * it.
+		 */
+		ret = ocfs2_rotate_tree_left(inode, handle, left_path, dealloc);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+		split_index--;
+		rec = &el->l_recs[split_index];
+
+		/*
+		 * Note that we don't pass split_rec here on purpose -
+		 * we've merged it into the left side.
+		 */
+		ret = ocfs2_merge_rec_right(inode, path_leaf_bh(left_path),
+					    handle, rec, el, split_index);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		BUG_ON(!ocfs2_is_empty_extent(&el->l_recs[0]));
+
+		ret = ocfs2_rotate_tree_left(inode, handle, left_path,
+					     dealloc);
+		/*
+		 * Error from this last rotate is not critical, so
+		 * print but don't bubble it up.
+		 */
+		if (ret)
+			mlog_errno(ret);
+		ret = 0;
+	} else {
+		/*
+		 * Merge a record to the left or right.
+		 *
+		 * 'contig_type' is relative to the existing record,
+		 * so for example, if we're "right contig", it's to
+		 * the record on the left (hence the left merge).
+		 */
+		if (ctxt->c_contig_type == CONTIG_RIGHT) {
+			ret = ocfs2_merge_rec_left(inode,
+						   path_leaf_bh(left_path),
+						   handle, split_rec, el,
+						   split_index);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		} else {
+			ret = ocfs2_merge_rec_right(inode,
+						    path_leaf_bh(left_path),
+						    handle, split_rec, el,
+						    split_index);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+
+		if (ctxt->c_split_covers_rec) {
+			/*
+			 * The merge may have left an empty extent in
+			 * our leaf. Try to rotate it away.
+			 */
+			ret = ocfs2_rotate_tree_left(inode, handle, left_path,
+						     dealloc);
+			if (ret)
+				mlog_errno(ret);
+			ret = 0;
+		}
+	}
+
+out:
+	return ret;
+}
+
+static void ocfs2_subtract_from_rec(struct super_block *sb,
+				    enum ocfs2_split_type split,
+				    struct ocfs2_extent_rec *rec,
+				    struct ocfs2_extent_rec *split_rec)
+{
+	u64 len_blocks;
+
+	len_blocks = ocfs2_clusters_to_blocks(sb,
+				le16_to_cpu(split_rec->e_leaf_clusters));
+
+	if (split == SPLIT_LEFT) {
+		/*
+		 * Region is on the left edge of the existing
+		 * record.
+		 */
+		le32_add_cpu(&rec->e_cpos,
+			     le16_to_cpu(split_rec->e_leaf_clusters));
+		le64_add_cpu(&rec->e_blkno, len_blocks);
+		le16_add_cpu(&rec->e_leaf_clusters,
+			     -le16_to_cpu(split_rec->e_leaf_clusters));
+	} else {
+		/*
+		 * Region is on the right edge of the existing
+		 * record.
+		 */
+		le16_add_cpu(&rec->e_leaf_clusters,
+			     -le16_to_cpu(split_rec->e_leaf_clusters));
+	}
+}
+
 /*
  * Do the final bits of extent record insertion at the target leaf
  * list. If this leaf is part of an allocation tree, it is assumed
@@ -1738,6 +2994,15 @@ static void ocfs2_insert_at_leaf(struct ocfs2_extent_rec *insert_rec,
 
 	BUG_ON(le16_to_cpu(el->l_tree_depth) != 0);
 
+	if (insert->ins_split != SPLIT_NONE) {
+		i = ocfs2_search_extent_list(el, le32_to_cpu(insert_rec->e_cpos));
+		BUG_ON(i == -1);
+		rec = &el->l_recs[i];
+		ocfs2_subtract_from_rec(inode->i_sb, insert->ins_split, rec,
+					insert_rec);
+		goto rotate;
+	}
+
 	/*
 	 * Contiguous insert - either left or right.
 	 */
@@ -1792,6 +3057,7 @@ static void ocfs2_insert_at_leaf(struct ocfs2_extent_rec *insert_rec,
 		return;
 	}
 
+rotate:
 	/*
 	 * Ok, we have to rotate.
 	 *
@@ -1815,13 +3081,53 @@ static inline void ocfs2_update_dinode_clusters(struct inode *inode,
 	spin_unlock(&OCFS2_I(inode)->ip_lock);
 }
 
+static void ocfs2_adjust_rightmost_records(struct inode *inode,
+					   handle_t *handle,
+					   struct ocfs2_path *path,
+					   struct ocfs2_extent_rec *insert_rec)
+{
+	int ret, i, next_free;
+	struct buffer_head *bh;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+
+	/*
+	 * Update everything except the leaf block.
+	 */
+	for (i = 0; i < path->p_tree_depth; i++) {
+		bh = path->p_node[i].bh;
+		el = path->p_node[i].el;
+
+		next_free = le16_to_cpu(el->l_next_free_rec);
+		if (next_free == 0) {
+			ocfs2_error(inode->i_sb,
+				    "Dinode %llu has a bad extent list",
+				    (unsigned long long)OCFS2_I(inode)->ip_blkno);
+			ret = -EIO;
+			return;
+		}
+
+		rec = &el->l_recs[next_free - 1];
+
+		rec->e_int_clusters = insert_rec->e_cpos;
+		le32_add_cpu(&rec->e_int_clusters,
+			     le16_to_cpu(insert_rec->e_leaf_clusters));
+		le32_add_cpu(&rec->e_int_clusters,
+			     -le32_to_cpu(rec->e_cpos));
+
+		ret = ocfs2_journal_dirty(handle, bh);
+		if (ret)
+			mlog_errno(ret);
+
+	}
+}
+
 static int ocfs2_append_rec_to_path(struct inode *inode, handle_t *handle,
 				    struct ocfs2_extent_rec *insert_rec,
 				    struct ocfs2_path *right_path,
 				    struct ocfs2_path **ret_left_path)
 {
-	int ret, i, next_free;
-	struct buffer_head *bh;
+	int ret, next_free;
 	struct ocfs2_extent_list *el;
 	struct ocfs2_path *left_path = NULL;
 
@@ -1887,40 +3193,7 @@ static int ocfs2_append_rec_to_path(struct inode *inode, handle_t *handle,
 		goto out;
 	}
 
-	el = path_root_el(right_path);
-	bh = path_root_bh(right_path);
-	i = 0;
-	while (1) {
-		struct ocfs2_extent_rec *rec;
-
-		next_free = le16_to_cpu(el->l_next_free_rec);
-		if (next_free == 0) {
-			ocfs2_error(inode->i_sb,
-				    "Dinode %llu has a bad extent list",
-				    (unsigned long long)OCFS2_I(inode)->ip_blkno);
-			ret = -EIO;
-			goto out;
-		}
-
-		rec = &el->l_recs[next_free - 1];
-
-		rec->e_int_clusters = insert_rec->e_cpos;
-		le32_add_cpu(&rec->e_int_clusters,
-			     le16_to_cpu(insert_rec->e_leaf_clusters));
-		le32_add_cpu(&rec->e_int_clusters,
-			     -le32_to_cpu(rec->e_cpos));
-
-		ret = ocfs2_journal_dirty(handle, bh);
-		if (ret)
-			mlog_errno(ret);
-
-		/* Don't touch the leaf node */
-		if (++i >= right_path->p_tree_depth)
-			break;
-
-		bh = right_path->p_node[i].bh;
-		el = right_path->p_node[i].el;
-	}
+	ocfs2_adjust_rightmost_records(inode, handle, right_path, insert_rec);
 
 	*ret_left_path = left_path;
 	ret = 0;
@@ -1931,6 +3204,83 @@ out:
 	return ret;
 }
 
+static void ocfs2_split_record(struct inode *inode,
+			       struct ocfs2_path *left_path,
+			       struct ocfs2_path *right_path,
+			       struct ocfs2_extent_rec *split_rec,
+			       enum ocfs2_split_type split)
+{
+	int index;
+	u32 cpos = le32_to_cpu(split_rec->e_cpos);
+	struct ocfs2_extent_list *left_el = NULL, *right_el, *insert_el, *el;
+	struct ocfs2_extent_rec *rec, *tmprec;
+
+	right_el = path_leaf_el(right_path);;
+	if (left_path)
+		left_el = path_leaf_el(left_path);
+
+	el = right_el;
+	insert_el = right_el;
+	index = ocfs2_search_extent_list(el, cpos);
+	if (index != -1) {
+		if (index == 0 && left_path) {
+			BUG_ON(ocfs2_is_empty_extent(&el->l_recs[0]));
+
+			/*
+			 * This typically means that the record
+			 * started in the left path but moved to the
+			 * right as a result of rotation. We either
+			 * move the existing record to the left, or we
+			 * do the later insert there.
+			 *
+			 * In this case, the left path should always
+			 * exist as the rotate code will have passed
+			 * it back for a post-insert update.
+			 */
+
+			if (split == SPLIT_LEFT) {
+				/*
+				 * It's a left split. Since we know
+				 * that the rotate code gave us an
+				 * empty extent in the left path, we
+				 * can just do the insert there.
+				 */
+				insert_el = left_el;
+			} else {
+				/*
+				 * Right split - we have to move the
+				 * existing record over to the left
+				 * leaf. The insert will be into the
+				 * newly created empty extent in the
+				 * right leaf.
+				 */
+				tmprec = &right_el->l_recs[index];
+				ocfs2_rotate_leaf(left_el, tmprec);
+				el = left_el;
+
+				memset(tmprec, 0, sizeof(*tmprec));
+				index = ocfs2_search_extent_list(left_el, cpos);
+				BUG_ON(index == -1);
+			}
+		}
+	} else {
+		BUG_ON(!left_path);
+		BUG_ON(!ocfs2_is_empty_extent(&left_el->l_recs[0]));
+		/*
+		 * Left path is easy - we can just allow the insert to
+		 * happen.
+		 */
+		el = left_el;
+		insert_el = left_el;
+		index = ocfs2_search_extent_list(el, cpos);
+		BUG_ON(index == -1);
+	}
+
+	rec = &el->l_recs[index];
+	ocfs2_subtract_from_rec(inode->i_sb, split, rec, split_rec);
+	ocfs2_rotate_leaf(insert_el, split_rec);
+}
+
 /*
  * This function only does inserts on an allocation b-tree. For dinode
  * lists, ocfs2_insert_at_leaf() is called directly.
@@ -1948,7 +3298,6 @@ static int ocfs2_insert_path(struct inode *inode,
 {
 	int ret, subtree_index;
 	struct buffer_head *leaf_bh = path_leaf_bh(right_path);
-	struct ocfs2_extent_list *el;
 
 	/*
 	 * Pass both paths to the journal. The majority of inserts
@@ -1984,9 +3333,18 @@ static int ocfs2_insert_path(struct inode *inode,
 		}
 	}
 
-	el = path_leaf_el(right_path);
+	if (insert->ins_split != SPLIT_NONE) {
+		/*
+		 * We could call ocfs2_insert_at_leaf() for some types
+		 * of splits, but it's easier to just let one seperate
+		 * function sort it all out.
+		 */
+		ocfs2_split_record(inode, left_path, right_path,
+				   insert_rec, insert->ins_split);
+	} else
+		ocfs2_insert_at_leaf(insert_rec, path_leaf_el(right_path),
+				     insert, inode);
 
-	ocfs2_insert_at_leaf(insert_rec, el, insert, inode);
 	ret = ocfs2_journal_dirty(handle, leaf_bh);
 	if (ret)
 		mlog_errno(ret);
@@ -2075,7 +3433,7 @@ static int ocfs2_do_insert_extent(struct inode *inode,
 	 * can wind up skipping both of these two special cases...
 	 */
 	if (rotate) {
-		ret = ocfs2_rotate_tree_right(inode, handle,
+		ret = ocfs2_rotate_tree_right(inode, handle, type->ins_split,
 					      le32_to_cpu(insert_rec->e_cpos),
 					      right_path, &left_path);
 		if (ret) {
@@ -2100,8 +3458,9 @@ static int ocfs2_do_insert_extent(struct inode *inode,
 	}
 
 out_update_clusters:
-	ocfs2_update_dinode_clusters(inode, di,
-				     le16_to_cpu(insert_rec->e_leaf_clusters));
+	if (type->ins_split == SPLIT_NONE)
+		ocfs2_update_dinode_clusters(inode, di,
+					     le16_to_cpu(insert_rec->e_leaf_clusters));
 
 	ret = ocfs2_journal_dirty(handle, di_bh);
 	if (ret)
@@ -2114,6 +3473,44 @@ out:
 	return ret;
 }
 
+static enum ocfs2_contig_type
+ocfs2_figure_merge_contig_type(struct inode *inode,
+			       struct ocfs2_extent_list *el, int index,
+			       struct ocfs2_extent_rec *split_rec)
+{
+	struct ocfs2_extent_rec *rec;
+	enum ocfs2_contig_type ret = CONTIG_NONE;
+
+	/*
+	 * We're careful to check for an empty extent record here -
+	 * the merge code will know what to do if it sees one.
+	 */
+
+	if (index > 0) {
+		rec = &el->l_recs[index - 1];
+		if (index == 1 && ocfs2_is_empty_extent(rec)) {
+			if (split_rec->e_cpos == el->l_recs[index].e_cpos)
+				ret = CONTIG_RIGHT;
+		} else {
+			ret = ocfs2_extent_contig(inode, rec, split_rec);
+		}
+	}
+
+	if (index < (le16_to_cpu(el->l_next_free_rec) - 1)) {
+		enum ocfs2_contig_type contig_type;
+
+		rec = &el->l_recs[index + 1];
+		contig_type = ocfs2_extent_contig(inode, rec, split_rec);
+
+		if (contig_type == CONTIG_LEFT && ret == CONTIG_RIGHT)
+			ret = CONTIG_LEFTRIGHT;
+		else if (ret == CONTIG_NONE)
+			ret = contig_type;
+	}
+
+	return ret;
+}
+
 static void ocfs2_figure_contig_type(struct inode *inode,
 				     struct ocfs2_insert_type *insert,
 				     struct ocfs2_extent_list *el,
@@ -2205,6 +3602,8 @@ static int ocfs2_figure_insert_type(struct inode *inode,
 	struct ocfs2_path *path = NULL;
 	struct buffer_head *bh = NULL;
 
+	insert->ins_split = SPLIT_NONE;
+
 	el = &di->id2.i_list;
 	insert->ins_tree_depth = le16_to_cpu(el->l_tree_depth);
 
@@ -2327,9 +3726,10 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
 			u32 cpos,
 			u64 start_blk,
 			u32 new_clusters,
+			u8 flags,
 			struct ocfs2_alloc_context *meta_ac)
 {
-	int status, shift;
+	int status;
 	struct buffer_head *last_eb_bh = NULL;
 	struct buffer_head *bh = NULL;
 	struct ocfs2_insert_type insert = {0, };
@@ -2350,6 +3750,7 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
 	rec.e_cpos = cpu_to_le32(cpos);
 	rec.e_blkno = cpu_to_le64(start_blk);
 	rec.e_leaf_clusters = cpu_to_le16(new_clusters);
+	rec.e_flags = flags;
 
 	status = ocfs2_figure_insert_type(inode, fe_bh, &last_eb_bh, &rec,
 					  &insert);
@@ -2364,55 +3765,16 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
 	     insert.ins_appending, insert.ins_contig, insert.ins_contig_index,
 	     insert.ins_free_records, insert.ins_tree_depth);
 
-	/*
-	 * Avoid growing the tree unless we're out of records and the
-	 * insert type requres one.
-	 */
-	if (insert.ins_contig != CONTIG_NONE || insert.ins_free_records)
-		goto out_add;
-
-	shift = ocfs2_find_branch_target(osb, inode, fe_bh, &bh);
-	if (shift < 0) {
-		status = shift;
-		mlog_errno(status);
-		goto bail;
-	}
-
-	/* We traveled all the way to the bottom of the allocation tree
-	 * and didn't find room for any more extents - we need to add
-	 * another tree level */
-	if (shift) {
-		BUG_ON(bh);
-		mlog(0, "need to shift tree depth "
-		     "(current = %d)\n", insert.ins_tree_depth);
-
-		/* ocfs2_shift_tree_depth will return us a buffer with
-		 * the new extent block (so we can pass that to
-		 * ocfs2_add_branch). */
-		status = ocfs2_shift_tree_depth(osb, handle, inode, fe_bh,
-						meta_ac, &bh);
-		if (status < 0) {
+	if (insert.ins_contig == CONTIG_NONE && insert.ins_free_records == 0) {
+		status = ocfs2_grow_tree(inode, handle, fe_bh,
+					 &insert.ins_tree_depth, &last_eb_bh,
+					 meta_ac);
+		if (status) {
 			mlog_errno(status);
 			goto bail;
 		}
-		insert.ins_tree_depth++;
-		/* Special case: we have room now if we shifted from
-		 * tree_depth 0 */
-		if (insert.ins_tree_depth == 1)
-			goto out_add;
-	}
-
-	/* call ocfs2_add_branch to add the final part of the tree with
-	 * the new data. */
-	mlog(0, "add branch. bh = %p\n", bh);
-	status = ocfs2_add_branch(osb, handle, inode, fe_bh, bh, last_eb_bh,
-				  meta_ac);
-	if (status < 0) {
-		mlog_errno(status);
-		goto bail;
 	}
 
-out_add:
 	/* Finally, we can add clusters. This might rotate the tree for us. */
 	status = ocfs2_do_insert_extent(inode, handle, fe_bh, &rec, &insert);
 	if (status < 0)
@@ -2431,7 +3793,720 @@ bail:
 	return status;
 }
 
-static inline int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
+static void ocfs2_make_right_split_rec(struct super_block *sb,
+				       struct ocfs2_extent_rec *split_rec,
+				       u32 cpos,
+				       struct ocfs2_extent_rec *rec)
+{
+	u32 rec_cpos = le32_to_cpu(rec->e_cpos);
+	u32 rec_range = rec_cpos + le16_to_cpu(rec->e_leaf_clusters);
+
+	memset(split_rec, 0, sizeof(struct ocfs2_extent_rec));
+
+	split_rec->e_cpos = cpu_to_le32(cpos);
+	split_rec->e_leaf_clusters = cpu_to_le16(rec_range - cpos);
+
+	split_rec->e_blkno = rec->e_blkno;
+	le64_add_cpu(&split_rec->e_blkno,
+		     ocfs2_clusters_to_blocks(sb, cpos - rec_cpos));
+
+	split_rec->e_flags = rec->e_flags;
+}
+
+static int ocfs2_split_and_insert(struct inode *inode,
+				  handle_t *handle,
+				  struct ocfs2_path *path,
+				  struct buffer_head *di_bh,
+				  struct buffer_head **last_eb_bh,
+				  int split_index,
+				  struct ocfs2_extent_rec *orig_split_rec,
+				  struct ocfs2_alloc_context *meta_ac)
+{
+	int ret = 0, depth;
+	unsigned int insert_range, rec_range, do_leftright = 0;
+	struct ocfs2_extent_rec tmprec;
+	struct ocfs2_extent_list *rightmost_el;
+	struct ocfs2_extent_rec rec;
+	struct ocfs2_extent_rec split_rec = *orig_split_rec;
+	struct ocfs2_insert_type insert;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_dinode *di;
+
+leftright:
+	/*
+	 * Store a copy of the record on the stack - it might move
+	 * around as the tree is manipulated below.
+	 */
+	rec = path_leaf_el(path)->l_recs[split_index];
+
+	di = (struct ocfs2_dinode *)di_bh->b_data;
+	rightmost_el = &di->id2.i_list;
+
+	depth = le16_to_cpu(rightmost_el->l_tree_depth);
+	if (depth) {
+		BUG_ON(!(*last_eb_bh));
+		eb = (struct ocfs2_extent_block *) (*last_eb_bh)->b_data;
+		rightmost_el = &eb->h_list;
+	}
+
+	if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
+	    le16_to_cpu(rightmost_el->l_count)) {
+		int old_depth = depth;
+
+		ret = ocfs2_grow_tree(inode, handle, di_bh, &depth, last_eb_bh,
+				      meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (old_depth != depth) {
+			eb = (struct ocfs2_extent_block *)(*last_eb_bh)->b_data;
+			rightmost_el = &eb->h_list;
+		}
+	}
+
+	memset(&insert, 0, sizeof(struct ocfs2_insert_type));
+	insert.ins_appending = APPEND_NONE;
+	insert.ins_contig = CONTIG_NONE;
+	insert.ins_free_records = le16_to_cpu(rightmost_el->l_count)
+		- le16_to_cpu(rightmost_el->l_next_free_rec);
+	insert.ins_tree_depth = depth;
+
+	insert_range = le32_to_cpu(split_rec.e_cpos) +
+		le16_to_cpu(split_rec.e_leaf_clusters);
+	rec_range = le32_to_cpu(rec.e_cpos) +
+		le16_to_cpu(rec.e_leaf_clusters);
+
+	if (split_rec.e_cpos == rec.e_cpos) {
+		insert.ins_split = SPLIT_LEFT;
+	} else if (insert_range == rec_range) {
+		insert.ins_split = SPLIT_RIGHT;
+	} else {
+		/*
+		 * Left/right split. We fake this as a right split
+		 * first and then make a second pass as a left split.
+		 */
+		insert.ins_split = SPLIT_RIGHT;
+
+		ocfs2_make_right_split_rec(inode->i_sb, &tmprec, insert_range,
+					   &rec);
+
+		split_rec = tmprec;
+
+		BUG_ON(do_leftright);
+		do_leftright = 1;
+	}
+
+	ret = ocfs2_do_insert_extent(inode, handle, di_bh, &split_rec,
+				     &insert);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (do_leftright == 1) {
+		u32 cpos;
+		struct ocfs2_extent_list *el;
+
+		do_leftright++;
+		split_rec = *orig_split_rec;
+
+		ocfs2_reinit_path(path, 1);
+
+		cpos = le32_to_cpu(split_rec.e_cpos);
+		ret = ocfs2_find_path(inode, path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		el = path_leaf_el(path);
+		split_index = ocfs2_search_extent_list(el, cpos);
+		goto leftright;
+	}
+out:
+
+	return ret;
+}
+
+/*
+ * Mark part or all of the extent record at split_index in the leaf
+ * pointed to by path as written. This removes the unwritten
+ * extent flag.
+ *
+ * Care is taken to handle contiguousness so as to not grow the tree.
+ *
+ * meta_ac is not strictly necessary - we only truly need it if growth
+ * of the tree is required. All other cases will degrade into a less
+ * optimal tree layout.
+ *
+ * last_eb_bh should be the rightmost leaf block for any inode with a
+ * btree. Since a split may grow the tree or a merge might shrink it, the caller cannot trust the contents of that buffer after this call.
+ *
+ * This code is optimized for readability - several passes might be
+ * made over certain portions of the tree. All of those blocks will
+ * have been brought into cache (and pinned via the journal), so the
+ * extra overhead is not expressed in terms of disk reads.
+ */
+static int __ocfs2_mark_extent_written(struct inode *inode,
+				       struct buffer_head *di_bh,
+				       handle_t *handle,
+				       struct ocfs2_path *path,
+				       int split_index,
+				       struct ocfs2_extent_rec *split_rec,
+				       struct ocfs2_alloc_context *meta_ac,
+				       struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret = 0;
+	struct ocfs2_extent_list *el = path_leaf_el(path);
+	struct buffer_head *eb_bh, *last_eb_bh = NULL;
+	struct ocfs2_extent_rec *rec = &el->l_recs[split_index];
+	struct ocfs2_merge_ctxt ctxt;
+	struct ocfs2_extent_list *rightmost_el;
+
+	if (!rec->e_flags & OCFS2_EXT_UNWRITTEN) {
+		ret = -EIO;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (le32_to_cpu(rec->e_cpos) > le32_to_cpu(split_rec->e_cpos) ||
+	    ((le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)) <
+	     (le32_to_cpu(split_rec->e_cpos) + le16_to_cpu(split_rec->e_leaf_clusters)))) {
+		ret = -EIO;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	eb_bh = path_leaf_bh(path);
+	ret = ocfs2_journal_access(handle, inode, eb_bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ctxt.c_contig_type = ocfs2_figure_merge_contig_type(inode, el,
+							    split_index,
+							    split_rec);
+
+	/*
+	 * The core merge / split code wants to know how much room is
+	 * left in this inodes allocation tree, so we pass the
+	 * rightmost extent list.
+	 */
+	if (path->p_tree_depth) {
+		struct ocfs2_extent_block *eb;
+		struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+
+		ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+				       le64_to_cpu(di->i_last_eb_blk),
+				       &last_eb_bh, OCFS2_BH_CACHED, inode);
+		if (ret) {
+			mlog_exit(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+		if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
+			OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
+			ret = -EROFS;
+			goto out;
+		}
+
+		rightmost_el = &eb->h_list;
+	} else
+		rightmost_el = path_root_el(path);
+
+	ctxt.c_used_tail_recs = le16_to_cpu(rightmost_el->l_next_free_rec);
+	if (ctxt.c_used_tail_recs > 0 &&
+	    ocfs2_is_empty_extent(&rightmost_el->l_recs[0]))
+		ctxt.c_used_tail_recs--;
+
+	if (rec->e_cpos == split_rec->e_cpos &&
+	    rec->e_leaf_clusters == split_rec->e_leaf_clusters)
+		ctxt.c_split_covers_rec = 1;
+	else
+		ctxt.c_split_covers_rec = 0;
+
+	ctxt.c_has_empty_extent = ocfs2_is_empty_extent(&el->l_recs[0]);
+
+	mlog(0, "index: %d, contig: %u, used_tail_recs: %u, "
+	     "has_empty: %u, split_covers: %u\n", split_index,
+	     ctxt.c_contig_type, ctxt.c_used_tail_recs,
+	     ctxt.c_has_empty_extent, ctxt.c_split_covers_rec);
+
+	if (ctxt.c_contig_type == CONTIG_NONE) {
+		if (ctxt.c_split_covers_rec)
+			el->l_recs[split_index] = *split_rec;
+		else
+			ret = ocfs2_split_and_insert(inode, handle, path, di_bh,
+						     &last_eb_bh, split_index,
+						     split_rec, meta_ac);
+		if (ret)
+			mlog_errno(ret);
+	} else {
+		ret = ocfs2_try_to_merge_extent(inode, handle, path,
+						split_index, split_rec,
+						dealloc, &ctxt);
+		if (ret)
+			mlog_errno(ret);
+	}
+
+	ocfs2_journal_dirty(handle, eb_bh);
+
+out:
+	brelse(last_eb_bh);
+	return ret;
+}
+
+/*
+ * Mark the already-existing extent at cpos as written for len clusters.
+ *
+ * If the existing extent is larger than the request, initiate a
+ * split. An attempt will be made at merging with adjacent extents.
+ *
+ * The caller is responsible for passing down meta_ac if we'll need it.
+ */
+int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
+			      handle_t *handle, u32 cpos, u32 len, u32 phys,
+			      struct ocfs2_alloc_context *meta_ac,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret, index;
+	u64 start_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys);
+	struct ocfs2_extent_rec split_rec;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_list *el;
+
+	mlog(0, "Inode %lu cpos %u, len %u, phys %u (%llu)\n",
+	     inode->i_ino, cpos, len, phys, (unsigned long long)start_blkno);
+
+	if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {
+		ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "
+			    "that are being written to, but the feature bit "
+			    "is not set in the super block.",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno);
+		ret = -EROFS;
+		goto out;
+	}
+
+	/*
+	 * XXX: This should be fixed up so that we just re-insert the
+	 * next extent records.
+	 */
+	ocfs2_extent_map_trunc(inode, 0);
+
+	left_path = ocfs2_new_inode_path(di_bh);
+	if (!left_path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_path(inode, left_path, cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+	el = path_leaf_el(left_path);
+
+	index = ocfs2_search_extent_list(el, cpos);
+	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has an extent at cpos %u which can no "
+			    "longer be found.\n",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
+		ret = -EROFS;
+		goto out;
+	}
+
+	memset(&split_rec, 0, sizeof(struct ocfs2_extent_rec));
+	split_rec.e_cpos = cpu_to_le32(cpos);
+	split_rec.e_leaf_clusters = cpu_to_le16(len);
+	split_rec.e_blkno = cpu_to_le64(start_blkno);
+	split_rec.e_flags = path_leaf_el(left_path)->l_recs[index].e_flags;
+	split_rec.e_flags &= ~OCFS2_EXT_UNWRITTEN;
+
+	ret = __ocfs2_mark_extent_written(inode, di_bh, handle, left_path,
+					  index, &split_rec, meta_ac, dealloc);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+}
+
+static int ocfs2_split_tree(struct inode *inode, struct buffer_head *di_bh,
+			    handle_t *handle, struct ocfs2_path *path,
+			    int index, u32 new_range,
+			    struct ocfs2_alloc_context *meta_ac)
+{
+	int ret, depth, credits = handle->h_buffer_credits;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+	struct buffer_head *last_eb_bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *rightmost_el, *el;
+	struct ocfs2_extent_rec split_rec;
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_insert_type insert;
+
+	/*
+	 * Setup the record to split before we grow the tree.
+	 */
+	el = path_leaf_el(path);
+	rec = &el->l_recs[index];
+	ocfs2_make_right_split_rec(inode->i_sb, &split_rec, new_range, rec);
+
+	depth = path->p_tree_depth;
+	if (depth > 0) {
+		ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+				       le64_to_cpu(di->i_last_eb_blk),
+				       &last_eb_bh, OCFS2_BH_CACHED, inode);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) last_eb_bh->b_data;
+		rightmost_el = &eb->h_list;
+	} else
+		rightmost_el = path_leaf_el(path);
+
+	credits += path->p_tree_depth + ocfs2_extend_meta_needed(di);
+	ret = ocfs2_extend_trans(handle, credits);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (le16_to_cpu(rightmost_el->l_next_free_rec) ==
+	    le16_to_cpu(rightmost_el->l_count)) {
+		int old_depth = depth;
+
+		ret = ocfs2_grow_tree(inode, handle, di_bh, &depth, &last_eb_bh,
+				      meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (old_depth != depth) {
+			eb = (struct ocfs2_extent_block *)last_eb_bh->b_data;
+			rightmost_el = &eb->h_list;
+		}
+	}
+
+	memset(&insert, 0, sizeof(struct ocfs2_insert_type));
+	insert.ins_appending = APPEND_NONE;
+	insert.ins_contig = CONTIG_NONE;
+	insert.ins_split = SPLIT_RIGHT;
+	insert.ins_free_records = le16_to_cpu(rightmost_el->l_count)
+		- le16_to_cpu(rightmost_el->l_next_free_rec);
+	insert.ins_tree_depth = depth;
+
+	ret = ocfs2_do_insert_extent(inode, handle, di_bh, &split_rec, &insert);
+	if (ret)
+		mlog_errno(ret);
+
+out:
+	brelse(last_eb_bh);
+	return ret;
+}
+
+static int ocfs2_truncate_rec(struct inode *inode, handle_t *handle,
+			      struct ocfs2_path *path, int index,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc,
+			      u32 cpos, u32 len)
+{
+	int ret;
+	u32 left_cpos, rec_range, trunc_range;
+	int wants_rotate = 0, is_rightmost_tree_rec = 0;
+	struct super_block *sb = inode->i_sb;
+	struct ocfs2_path *left_path = NULL;
+	struct ocfs2_extent_list *el = path_leaf_el(path);
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_extent_block *eb;
+
+	if (ocfs2_is_empty_extent(&el->l_recs[0]) && index > 0) {
+		ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		index--;
+	}
+
+	if (index == (le16_to_cpu(el->l_next_free_rec) - 1) &&
+	    path->p_tree_depth) {
+		/*
+		 * Check whether this is the rightmost tree record. If
+		 * we remove all of this record or part of its right
+		 * edge then an update of the record lengths above it
+		 * will be required.
+		 */
+		eb = (struct ocfs2_extent_block *)path_leaf_bh(path)->b_data;
+		if (eb->h_next_leaf_blk == 0)
+			is_rightmost_tree_rec = 1;
+	}
+
+	rec = &el->l_recs[index];
+	if (index == 0 && path->p_tree_depth &&
+	    le32_to_cpu(rec->e_cpos) == cpos) {
+		/*
+		 * Changing the leftmost offset (via partial or whole
+		 * record truncate) of an interior (or rightmost) path
+		 * means we have to update the subtree that is formed
+		 * by this leaf and the one to it's left.
+		 *
+		 * There are two cases we can skip:
+		 *   1) Path is the leftmost one in our inode tree.
+		 *   2) The leaf is rightmost and will be empty after
+		 *      we remove the extent record - the rotate code
+		 *      knows how to update the newly formed edge.
+		 */
+
+		ret = ocfs2_find_cpos_for_left_leaf(inode->i_sb, path,
+						    &left_cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (left_cpos && le16_to_cpu(el->l_next_free_rec) > 1) {
+			left_path = ocfs2_new_path(path_root_bh(path),
+						   path_root_el(path));
+			if (!left_path) {
+				ret = -ENOMEM;
+				mlog_errno(ret);
+				goto out;
+			}
+
+			ret = ocfs2_find_path(inode, left_path, left_cpos);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+	}
+
+	ret = ocfs2_extend_rotate_transaction(handle, 0,
+					      handle->h_buffer_credits,
+					      path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_path(inode, handle, path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access_path(inode, handle, left_path);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+	trunc_range = cpos + len;
+
+	if (le32_to_cpu(rec->e_cpos) == cpos && rec_range == trunc_range) {
+		int next_free;
+
+		memset(rec, 0, sizeof(*rec));
+		ocfs2_cleanup_merge(el, index);
+		wants_rotate = 1;
+
+		next_free = le16_to_cpu(el->l_next_free_rec);
+		if (is_rightmost_tree_rec && next_free > 1) {
+			/*
+			 * We skip the edge update if this path will
+			 * be deleted by the rotate code.
+			 */
+			rec = &el->l_recs[next_free - 1];
+			ocfs2_adjust_rightmost_records(inode, handle, path,
+						       rec);
+		}
+	} else if (le32_to_cpu(rec->e_cpos) == cpos) {
+		/* Remove leftmost portion of the record. */
+		le32_add_cpu(&rec->e_cpos, len);
+		le64_add_cpu(&rec->e_blkno, ocfs2_clusters_to_blocks(sb, len));
+		le16_add_cpu(&rec->e_leaf_clusters, -len);
+	} else if (rec_range == trunc_range) {
+		/* Remove rightmost portion of the record */
+		le16_add_cpu(&rec->e_leaf_clusters, -len);
+		if (is_rightmost_tree_rec)
+			ocfs2_adjust_rightmost_records(inode, handle, path, rec);
+	} else {
+		/* Caller should have trapped this. */
+		mlog(ML_ERROR, "Inode %llu: Invalid record truncate: (%u, %u) "
+		     "(%u, %u)\n", (unsigned long long)OCFS2_I(inode)->ip_blkno,
+		     le32_to_cpu(rec->e_cpos),
+		     le16_to_cpu(rec->e_leaf_clusters), cpos, len);
+		BUG();
+	}
+
+	if (left_path) {
+		int subtree_index;
+
+		subtree_index = ocfs2_find_subtree_root(inode, left_path, path);
+		ocfs2_complete_edge_insert(inode, handle, left_path, path,
+					   subtree_index);
+	}
+
+	ocfs2_journal_dirty(handle, path_leaf_bh(path));
+
+	ret = ocfs2_rotate_tree_left(inode, handle, path, dealloc);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+out:
+	ocfs2_free_path(left_path);
+	return ret;
+}
+
+int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
+			u32 cpos, u32 len, handle_t *handle,
+			struct ocfs2_alloc_context *meta_ac,
+			struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret, index;
+	u32 rec_range, trunc_range;
+	struct ocfs2_extent_rec *rec;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_path *path;
+
+	ocfs2_extent_map_trunc(inode, 0);
+
+	path = ocfs2_new_inode_path(di_bh);
+	if (!path) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_find_path(inode, path, cpos);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	el = path_leaf_el(path);
+	index = ocfs2_search_extent_list(el, cpos);
+	if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has an extent at cpos %u which can no "
+			    "longer be found.\n",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
+		ret = -EROFS;
+		goto out;
+	}
+
+	/*
+	 * We have 3 cases of extent removal:
+	 *   1) Range covers the entire extent rec
+	 *   2) Range begins or ends on one edge of the extent rec
+	 *   3) Range is in the middle of the extent rec (no shared edges)
+	 *
+	 * For case 1 we remove the extent rec and left rotate to
+	 * fill the hole.
+	 *
+	 * For case 2 we just shrink the existing extent rec, with a
+	 * tree update if the shrinking edge is also the edge of an
+	 * extent block.
+	 *
+	 * For case 3 we do a right split to turn the extent rec into
+	 * something case 2 can handle.
+	 */
+	rec = &el->l_recs[index];
+	rec_range = le32_to_cpu(rec->e_cpos) + ocfs2_rec_clusters(el, rec);
+	trunc_range = cpos + len;
+
+	BUG_ON(cpos < le32_to_cpu(rec->e_cpos) || trunc_range > rec_range);
+
+	mlog(0, "Inode %llu, remove (cpos %u, len %u). Existing index %d "
+	     "(cpos %u, len %u)\n",
+	     (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos, len, index,
+	     le32_to_cpu(rec->e_cpos), ocfs2_rec_clusters(el, rec));
+
+	if (le32_to_cpu(rec->e_cpos) == cpos || rec_range == trunc_range) {
+		ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
+					 cpos, len);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	} else {
+		ret = ocfs2_split_tree(inode, di_bh, handle, path, index,
+				       trunc_range, meta_ac);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * The split could have manipulated the tree enough to
+		 * move the record location, so we have to look for it again.
+		 */
+		ocfs2_reinit_path(path, 1);
+
+		ret = ocfs2_find_path(inode, path, cpos);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		el = path_leaf_el(path);
+		index = ocfs2_search_extent_list(el, cpos);
+		if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
+			ocfs2_error(inode->i_sb,
+				    "Inode %llu: split at cpos %u lost record.",
+				    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+				    cpos);
+			ret = -EROFS;
+			goto out;
+		}
+
+		/*
+		 * Double check our values here. If anything is fishy,
+		 * it's easier to catch it at the top level.
+		 */
+		rec = &el->l_recs[index];
+		rec_range = le32_to_cpu(rec->e_cpos) +
+			ocfs2_rec_clusters(el, rec);
+		if (rec_range != trunc_range) {
+			ocfs2_error(inode->i_sb,
+				    "Inode %llu: error after split at cpos %u"
+				    "trunc len %u, existing record is (%u,%u)",
+				    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+				    cpos, len, le32_to_cpu(rec->e_cpos),
+				    ocfs2_rec_clusters(el, rec));
+			ret = -EROFS;
+			goto out;
+		}
+
+		ret = ocfs2_truncate_rec(inode, handle, path, index, dealloc,
+					 cpos, len);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+out:
+	ocfs2_free_path(path);
+	return ret;
+}
+
+int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb)
 {
 	struct buffer_head *tl_bh = osb->osb_tl_bh;
 	struct ocfs2_dinode *di;
@@ -2464,10 +4539,10 @@ static int ocfs2_truncate_log_can_coalesce(struct ocfs2_truncate_log *tl,
 	return current_tail == new_start;
 }
 
-static int ocfs2_truncate_log_append(struct ocfs2_super *osb,
-				     handle_t *handle,
-				     u64 start_blk,
-				     unsigned int num_clusters)
+int ocfs2_truncate_log_append(struct ocfs2_super *osb,
+			      handle_t *handle,
+			      u64 start_blk,
+			      unsigned int num_clusters)
 {
 	int status, index;
 	unsigned int start_cluster, tl_count;
@@ -2623,7 +4698,7 @@ bail:
 }
 
 /* Expects you to already be holding tl_inode->i_mutex */
-static int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
+int __ocfs2_flush_truncate_log(struct ocfs2_super *osb)
 {
 	int status;
 	unsigned int num_to_flush;
@@ -2957,6 +5032,219 @@ int ocfs2_truncate_log_init(struct ocfs2_super *osb)
 	return status;
 }
 
+/*
+ * Delayed de-allocation of suballocator blocks.
+ *
+ * Some sets of block de-allocations might involve multiple suballocator inodes.
+ *
+ * The locking for this can get extremely complicated, especially when
+ * the suballocator inodes to delete from aren't known until deep
+ * within an unrelated codepath.
+ *
+ * ocfs2_extent_block structures are a good example of this - an inode
+ * btree could have been grown by any number of nodes each allocating
+ * out of their own suballoc inode.
+ *
+ * These structures allow the delay of block de-allocation until a
+ * later time, when locking of multiple cluster inodes won't cause
+ * deadlock.
+ */
+
+/*
+ * Describes a single block free from a suballocator
+ */
+struct ocfs2_cached_block_free {
+	struct ocfs2_cached_block_free		*free_next;
+	u64					free_blk;
+	unsigned int				free_bit;
+};
+
+struct ocfs2_per_slot_free_list {
+	struct ocfs2_per_slot_free_list		*f_next_suballocator;
+	int					f_inode_type;
+	int					f_slot;
+	struct ocfs2_cached_block_free		*f_first;
+};
+
+static int ocfs2_free_cached_items(struct ocfs2_super *osb,
+				   int sysfile_type,
+				   int slot,
+				   struct ocfs2_cached_block_free *head)
+{
+	int ret;
+	u64 bg_blkno;
+	handle_t *handle;
+	struct inode *inode;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_cached_block_free *tmp;
+
+	inode = ocfs2_get_system_file_inode(osb, sysfile_type, slot);
+	if (!inode) {
+		ret = -EINVAL;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	mutex_lock(&inode->i_mutex);
+
+	ret = ocfs2_meta_lock(inode, &di_bh, 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_mutex;
+	}
+
+	handle = ocfs2_start_trans(osb, OCFS2_SUBALLOC_FREE);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		goto out_unlock;
+	}
+
+	while (head) {
+		bg_blkno = ocfs2_which_suballoc_group(head->free_blk,
+						      head->free_bit);
+		mlog(0, "Free bit: (bit %u, blkno %llu)\n",
+		     head->free_bit, (unsigned long long)head->free_blk);
+
+		ret = ocfs2_free_suballoc_bits(handle, inode, di_bh,
+					       head->free_bit, bg_blkno, 1);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_journal;
+		}
+
+		ret = ocfs2_extend_trans(handle, OCFS2_SUBALLOC_FREE);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_journal;
+		}
+
+		tmp = head;
+		head = head->free_next;
+		kfree(tmp);
+	}
+
+out_journal:
+	ocfs2_commit_trans(osb, handle);
+
+out_unlock:
+	ocfs2_meta_unlock(inode, 1);
+	brelse(di_bh);
+out_mutex:
+	mutex_unlock(&inode->i_mutex);
+	iput(inode);
+out:
+	while(head) {
+		/* Premature exit may have left some dangling items. */
+		tmp = head;
+		head = head->free_next;
+		kfree(tmp);
+	}
+
+	return ret;
+}
+
+int ocfs2_run_deallocs(struct ocfs2_super *osb,
+		       struct ocfs2_cached_dealloc_ctxt *ctxt)
+{
+	int ret = 0, ret2;
+	struct ocfs2_per_slot_free_list *fl;
+
+	if (!ctxt)
+		return 0;
+
+	while (ctxt->c_first_suballocator) {
+		fl = ctxt->c_first_suballocator;
+
+		if (fl->f_first) {
+			mlog(0, "Free items: (type %u, slot %d)\n",
+			     fl->f_inode_type, fl->f_slot);
+			ret2 = ocfs2_free_cached_items(osb, fl->f_inode_type,
+						       fl->f_slot, fl->f_first);
+			if (ret2)
+				mlog_errno(ret2);
+			if (!ret)
+				ret = ret2;
+		}
+
+		ctxt->c_first_suballocator = fl->f_next_suballocator;
+		kfree(fl);
+	}
+
+	return ret;
+}
+
+static struct ocfs2_per_slot_free_list *
+ocfs2_find_per_slot_free_list(int type,
+			      int slot,
+			      struct ocfs2_cached_dealloc_ctxt *ctxt)
+{
+	struct ocfs2_per_slot_free_list *fl = ctxt->c_first_suballocator;
+
+	while (fl) {
+		if (fl->f_inode_type == type && fl->f_slot == slot)
+			return fl;
+
+		fl = fl->f_next_suballocator;
+	}
+
+	fl = kmalloc(sizeof(*fl), GFP_NOFS);
+	if (fl) {
+		fl->f_inode_type = type;
+		fl->f_slot = slot;
+		fl->f_first = NULL;
+		fl->f_next_suballocator = ctxt->c_first_suballocator;
+
+		ctxt->c_first_suballocator = fl;
+	}
+	return fl;
+}
+
+static int ocfs2_cache_block_dealloc(struct ocfs2_cached_dealloc_ctxt *ctxt,
+				     int type, int slot, u64 blkno,
+				     unsigned int bit)
+{
+	int ret;
+	struct ocfs2_per_slot_free_list *fl;
+	struct ocfs2_cached_block_free *item;
+
+	fl = ocfs2_find_per_slot_free_list(type, slot, ctxt);
+	if (fl == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	item = kmalloc(sizeof(*item), GFP_NOFS);
+	if (item == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	mlog(0, "Insert: (type %d, slot %u, bit %u, blk %llu)\n",
+	     type, slot, bit, (unsigned long long)blkno);
+
+	item->free_blk = blkno;
+	item->free_bit = bit;
+	item->free_next = fl->f_first;
+
+	fl->f_first = item;
+
+	ret = 0;
+out:
+	return ret;
+}
+
+static int ocfs2_cache_extent_block_free(struct ocfs2_cached_dealloc_ctxt *ctxt,
+					 struct ocfs2_extent_block *eb)
+{
+	return ocfs2_cache_block_dealloc(ctxt, EXTENT_ALLOC_SYSTEM_INODE,
+					 le16_to_cpu(eb->h_suballoc_slot),
+					 le64_to_cpu(eb->h_blkno),
+					 le16_to_cpu(eb->h_suballoc_bit));
+}
+
 /* This function will figure out whether the currently last extent
  * block will be deleted, and if it will, what the new last extent
  * block will be so we can update his h_next_leaf_blk field, as well
@@ -3238,27 +5526,10 @@ delete:
 			BUG_ON(le32_to_cpu(el->l_recs[0].e_cpos));
 			BUG_ON(le64_to_cpu(el->l_recs[0].e_blkno));
 
-			if (le16_to_cpu(eb->h_suballoc_slot) == 0) {
-				/*
-				 * This code only understands how to
-				 * lock the suballocator in slot 0,
-				 * which is fine because allocation is
-				 * only ever done out of that
-				 * suballocator too. A future version
-				 * might change that however, so avoid
-				 * a free if we don't know how to
-				 * handle it. This way an fs incompat
-				 * bit will not be necessary.
-				 */
-				ret = ocfs2_free_extent_block(handle,
-							      tc->tc_ext_alloc_inode,
-							      tc->tc_ext_alloc_bh,
-							      eb);
-
-				/* An error here is not fatal. */
-				if (ret < 0)
-					mlog_errno(ret);
-			}
+			ret = ocfs2_cache_extent_block_free(&tc->tc_dealloc, eb);
+			/* An error here is not fatal. */
+			if (ret < 0)
+				mlog_errno(ret);
 		} else {
 			deleted_eb = 0;
 		}
@@ -3397,9 +5668,9 @@ static int ocfs2_ordered_zero_func(handle_t *handle, struct buffer_head *bh)
 	return ocfs2_journal_dirty_data(handle, bh);
 }
 
-static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t isize,
-				     struct page **pages, int numpages,
-				     u64 phys, handle_t *handle)
+static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t start,
+				     loff_t end, struct page **pages,
+				     int numpages, u64 phys, handle_t *handle)
 {
 	int i, ret, partial = 0;
 	void *kaddr;
@@ -3412,26 +5683,14 @@ static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t isize,
 	if (numpages == 0)
 		goto out;
 
-	from = isize & (PAGE_CACHE_SIZE - 1); /* 1st page offset */
-	if (PAGE_CACHE_SHIFT > OCFS2_SB(sb)->s_clustersize_bits) {
-		/*
-		 * Since 'from' has been capped to a value below page
-		 * size, this calculation won't be able to overflow
-		 * 'to'
-		 */
-		to = ocfs2_align_bytes_to_clusters(sb, from);
-
-		/*
-		 * The truncate tail in this case should never contain
-		 * more than one page at maximum. The loop below also
-		 * assumes this.
-		 */
-		BUG_ON(numpages != 1);
-	}
-
+	to = PAGE_CACHE_SIZE;
 	for(i = 0; i < numpages; i++) {
 		page = pages[i];
 
+		from = start & (PAGE_CACHE_SIZE - 1);
+		if ((end >> PAGE_CACHE_SHIFT) == page->index)
+			to = end & (PAGE_CACHE_SIZE - 1);
+
 		BUG_ON(from > PAGE_CACHE_SIZE);
 		BUG_ON(to > PAGE_CACHE_SIZE);
 
@@ -3468,10 +5727,7 @@ static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t isize,
 
 		flush_dcache_page(page);
 
-		/*
-		 * Every page after the 1st one should be completely zero'd.
-		 */
-		from = 0;
+		start = (page->index + 1) << PAGE_CACHE_SHIFT;
 	}
 out:
 	if (pages) {
@@ -3484,24 +5740,26 @@ out:
 	}
 }
 
-static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page **pages,
-				int *num, u64 *phys)
+static int ocfs2_grab_eof_pages(struct inode *inode, loff_t start, loff_t end,
+				struct page **pages, int *num, u64 *phys)
 {
 	int i, numpages = 0, ret = 0;
-	unsigned int csize = OCFS2_SB(inode->i_sb)->s_clustersize;
 	unsigned int ext_flags;
 	struct super_block *sb = inode->i_sb;
 	struct address_space *mapping = inode->i_mapping;
 	unsigned long index;
-	u64 next_cluster_bytes;
+	loff_t last_page_bytes;
 
 	BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
+	BUG_ON(start > end);
 
-	/* Cluster boundary, so we don't need to grab any pages. */
-	if ((isize & (csize - 1)) == 0)
+	if (start == end)
 		goto out;
 
-	ret = ocfs2_extent_map_get_blocks(inode, isize >> sb->s_blocksize_bits,
+	BUG_ON(start >> OCFS2_SB(sb)->s_clustersize_bits !=
+	       (end - 1) >> OCFS2_SB(sb)->s_clustersize_bits);
+
+	ret = ocfs2_extent_map_get_blocks(inode, start >> sb->s_blocksize_bits,
 					  phys, NULL, &ext_flags);
 	if (ret) {
 		mlog_errno(ret);
@@ -3517,8 +5775,8 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
 	if (ext_flags & OCFS2_EXT_UNWRITTEN)
 		goto out;
 
-	next_cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, isize);
-	index = isize >> PAGE_CACHE_SHIFT;
+	last_page_bytes = PAGE_ALIGN(end);
+	index = start >> PAGE_CACHE_SHIFT;
 	do {
 		pages[numpages] = grab_cache_page(mapping, index);
 		if (!pages[numpages]) {
@@ -3529,7 +5787,7 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t isize, struct page *
 
 		numpages++;
 		index++;
-	} while (index < (next_cluster_bytes >> PAGE_CACHE_SHIFT));
+	} while (index < (last_page_bytes >> PAGE_CACHE_SHIFT));
 
 out:
 	if (ret != 0) {
@@ -3558,11 +5816,10 @@ out:
  * otherwise block_write_full_page() will skip writeout of pages past
  * i_size. The new_i_size parameter is passed for this reason.
  */
-int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
-				 u64 new_i_size)
+int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
+				  u64 range_start, u64 range_end)
 {
 	int ret, numpages;
-	loff_t endbyte;
 	struct page **pages = NULL;
 	u64 phys;
 
@@ -3581,7 +5838,8 @@ int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
 		goto out;
 	}
 
-	ret = ocfs2_grab_eof_pages(inode, new_i_size, pages, &numpages, &phys);
+	ret = ocfs2_grab_eof_pages(inode, range_start, range_end, pages,
+				   &numpages, &phys);
 	if (ret) {
 		mlog_errno(ret);
 		goto out;
@@ -3590,17 +5848,16 @@ int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
 	if (numpages == 0)
 		goto out;
 
-	ocfs2_zero_cluster_pages(inode, new_i_size, pages, numpages, phys,
-				 handle);
+	ocfs2_zero_cluster_pages(inode, range_start, range_end, pages,
+				 numpages, phys, handle);
 
 	/*
 	 * Initiate writeout of the pages we zero'd here. We don't
 	 * wait on them - the truncate_inode_pages() call later will
 	 * do that for us.
 	 */
-	endbyte = ocfs2_align_bytes_to_clusters(inode->i_sb, new_i_size);
-	ret = do_sync_mapping_range(inode->i_mapping, new_i_size,
-				    endbyte - 1, SYNC_FILE_RANGE_WRITE);
+	ret = do_sync_mapping_range(inode->i_mapping, range_start,
+				    range_end - 1, SYNC_FILE_RANGE_WRITE);
 	if (ret)
 		mlog_errno(ret);
 
@@ -3631,8 +5888,6 @@ int ocfs2_commit_truncate(struct ocfs2_super *osb,
 
 	mlog_entry_void();
 
-	down_write(&OCFS2_I(inode)->ip_alloc_sem);
-
 	new_highest_cpos = ocfs2_clusters_for_bytes(osb->sb,
 						     i_size_read(inode));
 
@@ -3754,7 +6009,6 @@ start:
 	goto start;
 
 bail:
-	up_write(&OCFS2_I(inode)->ip_alloc_sem);
 
 	ocfs2_schedule_truncate_log_flush(osb, 1);
 
@@ -3764,6 +6018,8 @@ bail:
 	if (handle)
 		ocfs2_commit_trans(osb, handle);
 
+	ocfs2_run_deallocs(osb, &tc->tc_dealloc);
+
 	ocfs2_free_path(path);
 
 	/* This will drop the ext_alloc cluster lock for us */
@@ -3774,23 +6030,18 @@ bail:
 }
 
 /*
- * Expects the inode to already be locked. This will figure out which
- * inodes need to be locked and will put them on the returned truncate
- * context.
+ * Expects the inode to already be locked.
  */
 int ocfs2_prepare_truncate(struct ocfs2_super *osb,
 			   struct inode *inode,
 			   struct buffer_head *fe_bh,
 			   struct ocfs2_truncate_context **tc)
 {
-	int status, metadata_delete, i;
+	int status;
 	unsigned int new_i_clusters;
 	struct ocfs2_dinode *fe;
 	struct ocfs2_extent_block *eb;
-	struct ocfs2_extent_list *el;
 	struct buffer_head *last_eb_bh = NULL;
-	struct inode *ext_alloc_inode = NULL;
-	struct buffer_head *ext_alloc_bh = NULL;
 
 	mlog_entry_void();
 
@@ -3810,12 +6061,9 @@ int ocfs2_prepare_truncate(struct ocfs2_super *osb,
 		mlog_errno(status);
 		goto bail;
 	}
+	ocfs2_init_dealloc_ctxt(&(*tc)->tc_dealloc);
 
-	metadata_delete = 0;
 	if (fe->id2.i_list.l_tree_depth) {
-		/* If we have a tree, then the truncate may result in
-		 * metadata deletes. Figure this out from the
-		 * rightmost leaf block.*/
 		status = ocfs2_read_block(osb, le64_to_cpu(fe->i_last_eb_blk),
 					  &last_eb_bh, OCFS2_BH_CACHED, inode);
 		if (status < 0) {
@@ -3830,43 +6078,10 @@ int ocfs2_prepare_truncate(struct ocfs2_super *osb,
 			status = -EIO;
 			goto bail;
 		}
-		el = &(eb->h_list);
-
-		i = 0;
-		if (ocfs2_is_empty_extent(&el->l_recs[0]))
-			i = 1;
-		/*
-		 * XXX: Should we check that next_free_rec contains
-		 * the extent?
-		 */
-		if (le32_to_cpu(el->l_recs[i].e_cpos) >= new_i_clusters)
-			metadata_delete = 1;
 	}
 
 	(*tc)->tc_last_eb_bh = last_eb_bh;
 
-	if (metadata_delete) {
-		mlog(0, "Will have to delete metadata for this trunc. "
-		     "locking allocator.\n");
-		ext_alloc_inode = ocfs2_get_system_file_inode(osb, EXTENT_ALLOC_SYSTEM_INODE, 0);
-		if (!ext_alloc_inode) {
-			status = -ENOMEM;
-			mlog_errno(status);
-			goto bail;
-		}
-
-		mutex_lock(&ext_alloc_inode->i_mutex);
-		(*tc)->tc_ext_alloc_inode = ext_alloc_inode;
-
-		status = ocfs2_meta_lock(ext_alloc_inode, &ext_alloc_bh, 1);
-		if (status < 0) {
-			mlog_errno(status);
-			goto bail;
-		}
-		(*tc)->tc_ext_alloc_bh = ext_alloc_bh;
-		(*tc)->tc_ext_alloc_locked = 1;
-	}
-
 	status = 0;
 bail:
 	if (status < 0) {
@@ -3880,16 +6095,13 @@ bail:
 
 static void ocfs2_free_truncate_context(struct ocfs2_truncate_context *tc)
 {
-	if (tc->tc_ext_alloc_inode) {
-		if (tc->tc_ext_alloc_locked)
-			ocfs2_meta_unlock(tc->tc_ext_alloc_inode, 1);
-
-		mutex_unlock(&tc->tc_ext_alloc_inode->i_mutex);
-		iput(tc->tc_ext_alloc_inode);
-	}
-
-	if (tc->tc_ext_alloc_bh)
-		brelse(tc->tc_ext_alloc_bh);
+	/*
+	 * The caller is responsible for completing deallocation
+	 * before freeing the context.
+	 */
+	if (tc->tc_dealloc.c_first_suballocator != NULL)
+		mlog(ML_NOTICE,
+		     "Truncate completion has non-empty dealloc context\n");
 
 	if (tc->tc_last_eb_bh)
 		brelse(tc->tc_last_eb_bh);
diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
index fbcb5934a08..990df48ae8d 100644
--- a/fs/ocfs2/alloc.h
+++ b/fs/ocfs2/alloc.h
@@ -34,7 +34,17 @@ int ocfs2_insert_extent(struct ocfs2_super *osb,
 			u32 cpos,
 			u64 start_blk,
 			u32 new_clusters,
+			u8 flags,
 			struct ocfs2_alloc_context *meta_ac);
+struct ocfs2_cached_dealloc_ctxt;
+int ocfs2_mark_extent_written(struct inode *inode, struct buffer_head *di_bh,
+			      handle_t *handle, u32 cpos, u32 len, u32 phys,
+			      struct ocfs2_alloc_context *meta_ac,
+			      struct ocfs2_cached_dealloc_ctxt *dealloc);
+int ocfs2_remove_extent(struct inode *inode, struct buffer_head *di_bh,
+			u32 cpos, u32 len, handle_t *handle,
+			struct ocfs2_alloc_context *meta_ac,
+			struct ocfs2_cached_dealloc_ctxt *dealloc);
 int ocfs2_num_free_extents(struct ocfs2_super *osb,
 			   struct inode *inode,
 			   struct ocfs2_dinode *fe);
@@ -62,17 +72,41 @@ int ocfs2_begin_truncate_log_recovery(struct ocfs2_super *osb,
 				      struct ocfs2_dinode **tl_copy);
 int ocfs2_complete_truncate_log_recovery(struct ocfs2_super *osb,
 					 struct ocfs2_dinode *tl_copy);
+int ocfs2_truncate_log_needs_flush(struct ocfs2_super *osb);
+int ocfs2_truncate_log_append(struct ocfs2_super *osb,
+			      handle_t *handle,
+			      u64 start_blk,
+			      unsigned int num_clusters);
+int __ocfs2_flush_truncate_log(struct ocfs2_super *osb);
+
+/*
+ * Process local structure which describes the block unlinks done
+ * during an operation. This is populated via
+ * ocfs2_cache_block_dealloc().
+ *
+ * ocfs2_run_deallocs() should be called after the potentially
+ * de-allocating routines. No journal handles should be open, and most
+ * locks should have been dropped.
+ */
+struct ocfs2_cached_dealloc_ctxt {
+	struct ocfs2_per_slot_free_list		*c_first_suballocator;
+};
+static inline void ocfs2_init_dealloc_ctxt(struct ocfs2_cached_dealloc_ctxt *c)
+{
+	c->c_first_suballocator = NULL;
+}
+int ocfs2_run_deallocs(struct ocfs2_super *osb,
+		       struct ocfs2_cached_dealloc_ctxt *ctxt);
 
 struct ocfs2_truncate_context {
-	struct inode *tc_ext_alloc_inode;
-	struct buffer_head *tc_ext_alloc_bh;
+	struct ocfs2_cached_dealloc_ctxt tc_dealloc;
 	int tc_ext_alloc_locked; /* is it cluster locked? */
 	/* these get destroyed once it's passed to ocfs2_commit_truncate. */
 	struct buffer_head *tc_last_eb_bh;
 };
 
-int ocfs2_zero_tail_for_truncate(struct inode *inode, handle_t *handle,
-				 u64 new_i_size);
+int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
+				  u64 range_start, u64 range_end);
 int ocfs2_prepare_truncate(struct ocfs2_super *osb,
 			   struct inode *inode,
 			   struct buffer_head *fe_bh,
@@ -84,6 +118,7 @@ int ocfs2_commit_truncate(struct ocfs2_super *osb,
 
 int ocfs2_find_leaf(struct inode *inode, struct ocfs2_extent_list *root_el,
 		    u32 cpos, struct buffer_head **leaf_bh);
+int ocfs2_search_extent_list(struct ocfs2_extent_list *el, u32 v_cluster);
 
 /*
  * Helper function to look at the # of clusters in an extent record.
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index a480b09c79b..84bf6e79de2 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -684,6 +684,8 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
 	     bh = bh->b_this_page, block_start += bsize) {
 		block_end = block_start + bsize;
 
+		clear_buffer_new(bh);
+
 		/*
 		 * Ignore blocks outside of our i/o range -
 		 * they may belong to unallocated clusters.
@@ -698,9 +700,8 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
 		 * For an allocating write with cluster size >= page
 		 * size, we always write the entire page.
 		 */
-
-		if (buffer_new(bh))
-			clear_buffer_new(bh);
+		if (new)
+			set_buffer_new(bh);
 
 		if (!buffer_mapped(bh)) {
 			map_bh(bh, inode->i_sb, *p_blkno);
@@ -711,7 +712,8 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
 			if (!buffer_uptodate(bh))
 				set_buffer_uptodate(bh);
 		} else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
-		     (block_start < from || block_end > to)) {
+			   !buffer_new(bh) &&
+			   (block_start < from || block_end > to)) {
 			ll_rw_block(READ, 1, &bh);
 			*wait_bh++=bh;
 		}
@@ -738,18 +740,13 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
 	bh = head;
 	block_start = 0;
 	do {
-		void *kaddr;
-
 		block_end = block_start + bsize;
 		if (block_end <= from)
 			goto next_bh;
 		if (block_start >= to)
 			break;
 
-		kaddr = kmap_atomic(page, KM_USER0);
-		memset(kaddr+block_start, 0, bh->b_size);
-		flush_dcache_page(page);
-		kunmap_atomic(kaddr, KM_USER0);
+		zero_user_page(page, block_start, bh->b_size, KM_USER0);
 		set_buffer_uptodate(bh);
 		mark_buffer_dirty(bh);
 
@@ -761,217 +758,240 @@ next_bh:
 	return ret;
 }
 
+#if (PAGE_CACHE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
+#define OCFS2_MAX_CTXT_PAGES	1
+#else
+#define OCFS2_MAX_CTXT_PAGES	(OCFS2_MAX_CLUSTERSIZE / PAGE_CACHE_SIZE)
+#endif
+
+#define OCFS2_MAX_CLUSTERS_PER_PAGE	(PAGE_CACHE_SIZE / OCFS2_MIN_CLUSTERSIZE)
+
 /*
- * This will copy user data from the buffer page in the splice
- * context.
- *
- * For now, we ignore SPLICE_F_MOVE as that would require some extra
- * communication out all the way to ocfs2_write().
+ * Describe the state of a single cluster to be written to.
  */
-int ocfs2_map_and_write_splice_data(struct inode *inode,
-				  struct ocfs2_write_ctxt *wc, u64 *p_blkno,
-				  unsigned int *ret_from, unsigned int *ret_to)
+struct ocfs2_write_cluster_desc {
+	u32		c_cpos;
+	u32		c_phys;
+	/*
+	 * Give this a unique field because c_phys eventually gets
+	 * filled.
+	 */
+	unsigned	c_new;
+	unsigned	c_unwritten;
+};
+
+static inline int ocfs2_should_zero_cluster(struct ocfs2_write_cluster_desc *d)
 {
-	int ret;
-	unsigned int to, from, cluster_start, cluster_end;
-	char *src, *dst;
-	struct ocfs2_splice_write_priv *sp = wc->w_private;
-	struct pipe_buffer *buf = sp->s_buf;
-	unsigned long bytes, src_from;
-	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	return d->c_new || d->c_unwritten;
+}
 
-	ocfs2_figure_cluster_boundaries(osb, wc->w_cpos, &cluster_start,
-					&cluster_end);
+struct ocfs2_write_ctxt {
+	/* Logical cluster position / len of write */
+	u32				w_cpos;
+	u32				w_clen;
 
-	from = sp->s_offset;
-	src_from = sp->s_buf_offset;
-	bytes = wc->w_count;
+	struct ocfs2_write_cluster_desc	w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
 
-	if (wc->w_large_pages) {
-		/*
-		 * For cluster size < page size, we have to
-		 * calculate pos within the cluster and obey
-		 * the rightmost boundary.
-		 */
-		bytes = min(bytes, (unsigned long)(osb->s_clustersize
-				   - (wc->w_pos & (osb->s_clustersize - 1))));
-	}
-	to = from + bytes;
+	/*
+	 * This is true if page_size > cluster_size.
+	 *
+	 * It triggers a set of special cases during write which might
+	 * have to deal with allocating writes to partial pages.
+	 */
+	unsigned int			w_large_pages;
+
+	/*
+	 * Pages involved in this write.
+	 *
+	 * w_target_page is the page being written to by the user.
+	 *
+	 * w_pages is an array of pages which always contains
+	 * w_target_page, and in the case of an allocating write with
+	 * page_size < cluster size, it will contain zero'd and mapped
+	 * pages adjacent to w_target_page which need to be written
+	 * out in so that future reads from that region will get
+	 * zero's.
+	 */
+	struct page			*w_pages[OCFS2_MAX_CTXT_PAGES];
+	unsigned int			w_num_pages;
+	struct page			*w_target_page;
 
-	BUG_ON(from > PAGE_CACHE_SIZE);
-	BUG_ON(to > PAGE_CACHE_SIZE);
-	BUG_ON(from < cluster_start);
-	BUG_ON(to > cluster_end);
+	/*
+	 * ocfs2_write_end() uses this to know what the real range to
+	 * write in the target should be.
+	 */
+	unsigned int			w_target_from;
+	unsigned int			w_target_to;
 
-	if (wc->w_this_page_new)
-		ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
-					    cluster_start, cluster_end, 1);
-	else
-		ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
-					    from, to, 0);
-	if (ret) {
-		mlog_errno(ret);
-		goto out;
+	/*
+	 * We could use journal_current_handle() but this is cleaner,
+	 * IMHO -Mark
+	 */
+	handle_t			*w_handle;
+
+	struct buffer_head		*w_di_bh;
+
+	struct ocfs2_cached_dealloc_ctxt w_dealloc;
+};
+
+static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
+{
+	int i;
+
+	for(i = 0; i < wc->w_num_pages; i++) {
+		if (wc->w_pages[i] == NULL)
+			continue;
+
+		unlock_page(wc->w_pages[i]);
+		mark_page_accessed(wc->w_pages[i]);
+		page_cache_release(wc->w_pages[i]);
 	}
 
-	src = buf->ops->map(sp->s_pipe, buf, 1);
-	dst = kmap_atomic(wc->w_this_page, KM_USER1);
-	memcpy(dst + from, src + src_from, bytes);
-	kunmap_atomic(wc->w_this_page, KM_USER1);
-	buf->ops->unmap(sp->s_pipe, buf, src);
+	brelse(wc->w_di_bh);
+	kfree(wc);
+}
+
+static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
+				  struct ocfs2_super *osb, loff_t pos,
+				  unsigned len, struct buffer_head *di_bh)
+{
+	struct ocfs2_write_ctxt *wc;
+
+	wc = kzalloc(sizeof(struct ocfs2_write_ctxt), GFP_NOFS);
+	if (!wc)
+		return -ENOMEM;
 
-	wc->w_finished_copy = 1;
+	wc->w_cpos = pos >> osb->s_clustersize_bits;
+	wc->w_clen = ocfs2_clusters_for_bytes(osb->sb, len);
+	get_bh(di_bh);
+	wc->w_di_bh = di_bh;
 
-	*ret_from = from;
-	*ret_to = to;
-out:
+	if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
+		wc->w_large_pages = 1;
+	else
+		wc->w_large_pages = 0;
+
+	ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
+
+	*wcp = wc;
 
-	return bytes ? (unsigned int)bytes : ret;
+	return 0;
 }
 
 /*
- * This will copy user data from the iovec in the buffered write
- * context.
+ * If a page has any new buffers, zero them out here, and mark them uptodate
+ * and dirty so they'll be written out (in order to prevent uninitialised
+ * block data from leaking). And clear the new bit.
  */
-int ocfs2_map_and_write_user_data(struct inode *inode,
-				  struct ocfs2_write_ctxt *wc, u64 *p_blkno,
-				  unsigned int *ret_from, unsigned int *ret_to)
+static void ocfs2_zero_new_buffers(struct page *page, unsigned from, unsigned to)
 {
-	int ret;
-	unsigned int to, from, cluster_start, cluster_end;
-	unsigned long bytes, src_from;
-	char *dst;
-	struct ocfs2_buffered_write_priv *bp = wc->w_private;
-	const struct iovec *cur_iov = bp->b_cur_iov;
-	char __user *buf;
-	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	unsigned int block_start, block_end;
+	struct buffer_head *head, *bh;
 
-	ocfs2_figure_cluster_boundaries(osb, wc->w_cpos, &cluster_start,
-					&cluster_end);
+	BUG_ON(!PageLocked(page));
+	if (!page_has_buffers(page))
+		return;
 
-	buf = cur_iov->iov_base + bp->b_cur_off;
-	src_from = (unsigned long)buf & ~PAGE_CACHE_MASK;
+	bh = head = page_buffers(page);
+	block_start = 0;
+	do {
+		block_end = block_start + bh->b_size;
 
-	from = wc->w_pos & (PAGE_CACHE_SIZE - 1);
+		if (buffer_new(bh)) {
+			if (block_end > from && block_start < to) {
+				if (!PageUptodate(page)) {
+					unsigned start, end;
 
-	/*
-	 * This is a lot of comparisons, but it reads quite
-	 * easily, which is important here.
-	 */
-	/* Stay within the src page */
-	bytes = PAGE_SIZE - src_from;
-	/* Stay within the vector */
-	bytes = min(bytes,
-		    (unsigned long)(cur_iov->iov_len - bp->b_cur_off));
-	/* Stay within count */
-	bytes = min(bytes, (unsigned long)wc->w_count);
-	/*
-	 * For clustersize > page size, just stay within
-	 * target page, otherwise we have to calculate pos
-	 * within the cluster and obey the rightmost
-	 * boundary.
-	 */
-	if (wc->w_large_pages) {
-		/*
-		 * For cluster size < page size, we have to
-		 * calculate pos within the cluster and obey
-		 * the rightmost boundary.
-		 */
-		bytes = min(bytes, (unsigned long)(osb->s_clustersize
-				   - (wc->w_pos & (osb->s_clustersize - 1))));
-	} else {
-		/*
-		 * cluster size > page size is the most common
-		 * case - we just stay within the target page
-		 * boundary.
-		 */
-		bytes = min(bytes, PAGE_CACHE_SIZE - from);
-	}
+					start = max(from, block_start);
+					end = min(to, block_end);
 
-	to = from + bytes;
+					zero_user_page(page, start, end - start, KM_USER0);
+					set_buffer_uptodate(bh);
+				}
 
-	BUG_ON(from > PAGE_CACHE_SIZE);
-	BUG_ON(to > PAGE_CACHE_SIZE);
-	BUG_ON(from < cluster_start);
-	BUG_ON(to > cluster_end);
+				clear_buffer_new(bh);
+				mark_buffer_dirty(bh);
+			}
+		}
 
-	if (wc->w_this_page_new)
-		ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
-					    cluster_start, cluster_end, 1);
-	else
-		ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
-					    from, to, 0);
-	if (ret) {
-		mlog_errno(ret);
-		goto out;
-	}
+		block_start = block_end;
+		bh = bh->b_this_page;
+	} while (bh != head);
+}
 
-	dst = kmap(wc->w_this_page);
-	memcpy(dst + from, bp->b_src_buf + src_from, bytes);
-	kunmap(wc->w_this_page);
+/*
+ * Only called when we have a failure during allocating write to write
+ * zero's to the newly allocated region.
+ */
+static void ocfs2_write_failure(struct inode *inode,
+				struct ocfs2_write_ctxt *wc,
+				loff_t user_pos, unsigned user_len)
+{
+	int i;
+	unsigned from, to;
+	struct page *tmppage;
 
-	/*
-	 * XXX: This is slow, but simple. The caller of
-	 * ocfs2_buffered_write_cluster() is responsible for
-	 * passing through the iovecs, so it's difficult to
-	 * predict what our next step is in here after our
-	 * initial write. A future version should be pushing
-	 * that iovec manipulation further down.
-	 *
-	 * By setting this, we indicate that a copy from user
-	 * data was done, and subsequent calls for this
-	 * cluster will skip copying more data.
-	 */
-	wc->w_finished_copy = 1;
+	ocfs2_zero_new_buffers(wc->w_target_page, user_pos, user_len);
 
-	*ret_from = from;
-	*ret_to = to;
-out:
+	if (wc->w_large_pages) {
+		from = wc->w_target_from;
+		to = wc->w_target_to;
+	} else {
+		from = 0;
+		to = PAGE_CACHE_SIZE;
+	}
+
+	for(i = 0; i < wc->w_num_pages; i++) {
+		tmppage = wc->w_pages[i];
 
-	return bytes ? (unsigned int)bytes : ret;
+		if (ocfs2_should_order_data(inode))
+			walk_page_buffers(wc->w_handle, page_buffers(tmppage),
+					  from, to, NULL,
+					  ocfs2_journal_dirty_data);
+
+		block_commit_write(tmppage, from, to);
+	}
 }
 
-/*
- * Map, fill and write a page to disk.
- *
- * The work of copying data is done via callback.  Newly allocated
- * pages which don't take user data will be zero'd (set 'new' to
- * indicate an allocating write)
- *
- * Returns a negative error code or the number of bytes copied into
- * the page.
- */
-static int ocfs2_write_data_page(struct inode *inode, handle_t *handle,
-				 u64 *p_blkno, struct page *page,
-				 struct ocfs2_write_ctxt *wc, int new)
+static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
+					struct ocfs2_write_ctxt *wc,
+					struct page *page, u32 cpos,
+					loff_t user_pos, unsigned user_len,
+					int new)
 {
-	int ret, copied = 0;
-	unsigned int from = 0, to = 0;
+	int ret;
+	unsigned int map_from = 0, map_to = 0;
 	unsigned int cluster_start, cluster_end;
-	unsigned int zero_from = 0, zero_to = 0;
+	unsigned int user_data_from = 0, user_data_to = 0;
 
-	ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), wc->w_cpos,
+	ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
 					&cluster_start, &cluster_end);
 
-	if ((wc->w_pos >> PAGE_CACHE_SHIFT) == page->index
-	    && !wc->w_finished_copy) {
-
-		wc->w_this_page = page;
-		wc->w_this_page_new = new;
-		ret = wc->w_write_data_page(inode, wc, p_blkno, &from, &to);
-		if (ret < 0) {
+	if (page == wc->w_target_page) {
+		map_from = user_pos & (PAGE_CACHE_SIZE - 1);
+		map_to = map_from + user_len;
+
+		if (new)
+			ret = ocfs2_map_page_blocks(page, p_blkno, inode,
+						    cluster_start, cluster_end,
+						    new);
+		else
+			ret = ocfs2_map_page_blocks(page, p_blkno, inode,
+						    map_from, map_to, new);
+		if (ret) {
 			mlog_errno(ret);
 			goto out;
 		}
 
-		copied = ret;
-
-		zero_from = from;
-		zero_to = to;
+		user_data_from = map_from;
+		user_data_to = map_to;
 		if (new) {
-			from = cluster_start;
-			to = cluster_end;
+			map_from = cluster_start;
+			map_to = cluster_end;
 		}
+
+		wc->w_target_from = map_from;
+		wc->w_target_to = map_to;
 	} else {
 		/*
 		 * If we haven't allocated the new page yet, we
@@ -980,11 +1000,11 @@ static int ocfs2_write_data_page(struct inode *inode, handle_t *handle,
 		 */
 		BUG_ON(!new);
 
-		from = cluster_start;
-		to = cluster_end;
+		map_from = cluster_start;
+		map_to = cluster_end;
 
 		ret = ocfs2_map_page_blocks(page, p_blkno, inode,
-					    cluster_start, cluster_end, 1);
+					    cluster_start, cluster_end, new);
 		if (ret) {
 			mlog_errno(ret);
 			goto out;
@@ -1003,108 +1023,113 @@ static int ocfs2_write_data_page(struct inode *inode, handle_t *handle,
 	 */
 	if (new && !PageUptodate(page))
 		ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
-					 wc->w_cpos, zero_from, zero_to);
+					 cpos, user_data_from, user_data_to);
 
 	flush_dcache_page(page);
 
-	if (ocfs2_should_order_data(inode)) {
-		ret = walk_page_buffers(handle,
-					page_buffers(page),
-					from, to, NULL,
-					ocfs2_journal_dirty_data);
-		if (ret < 0)
-			mlog_errno(ret);
-	}
-
-	/*
-	 * We don't use generic_commit_write() because we need to
-	 * handle our own i_size update.
-	 */
-	ret = block_commit_write(page, from, to);
-	if (ret)
-		mlog_errno(ret);
 out:
-
-	return copied ? copied : ret;
+	return ret;
 }
 
 /*
- * Do the actual write of some data into an inode. Optionally allocate
- * in order to fulfill the write.
- *
- * cpos is the logical cluster offset within the file to write at
- *
- * 'phys' is the physical mapping of that offset. a 'phys' value of
- * zero indicates that allocation is required. In this case, data_ac
- * and meta_ac should be valid (meta_ac can be null if metadata
- * allocation isn't required).
+ * This function will only grab one clusters worth of pages.
  */
-static ssize_t ocfs2_write(struct file *file, u32 phys, handle_t *handle,
-			   struct buffer_head *di_bh,
-			   struct ocfs2_alloc_context *data_ac,
-			   struct ocfs2_alloc_context *meta_ac,
-			   struct ocfs2_write_ctxt *wc)
+static int ocfs2_grab_pages_for_write(struct address_space *mapping,
+				      struct ocfs2_write_ctxt *wc,
+				      u32 cpos, loff_t user_pos, int new,
+				      struct page *mmap_page)
 {
-	int ret, i, numpages = 1, new;
-	unsigned int copied = 0;
-	u32 tmp_pos;
-	u64 v_blkno, p_blkno;
-	struct address_space *mapping = file->f_mapping;
+	int ret = 0, i;
+	unsigned long start, target_index, index;
 	struct inode *inode = mapping->host;
-	unsigned long index, start;
-	struct page **cpages;
 
-	new = phys == 0 ? 1 : 0;
+	target_index = user_pos >> PAGE_CACHE_SHIFT;
 
 	/*
 	 * Figure out how many pages we'll be manipulating here. For
 	 * non allocating write, we just change the one
 	 * page. Otherwise, we'll need a whole clusters worth.
 	 */
-	if (new)
-		numpages = ocfs2_pages_per_cluster(inode->i_sb);
-
-	cpages = kzalloc(sizeof(*cpages) * numpages, GFP_NOFS);
-	if (!cpages) {
-		ret = -ENOMEM;
-		mlog_errno(ret);
-		return ret;
-	}
-
-	/*
-	 * Fill our page array first. That way we've grabbed enough so
-	 * that we can zero and flush if we error after adding the
-	 * extent.
-	 */
 	if (new) {
-		start = ocfs2_align_clusters_to_page_index(inode->i_sb,
-							   wc->w_cpos);
-		v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, wc->w_cpos);
+		wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
+		start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
 	} else {
-		start = wc->w_pos >> PAGE_CACHE_SHIFT;
-		v_blkno = wc->w_pos >> inode->i_sb->s_blocksize_bits;
+		wc->w_num_pages = 1;
+		start = target_index;
 	}
 
-	for(i = 0; i < numpages; i++) {
+	for(i = 0; i < wc->w_num_pages; i++) {
 		index = start + i;
 
-		cpages[i] = find_or_create_page(mapping, index, GFP_NOFS);
-		if (!cpages[i]) {
-			ret = -ENOMEM;
-			mlog_errno(ret);
-			goto out;
+		if (index == target_index && mmap_page) {
+			/*
+			 * ocfs2_pagemkwrite() is a little different
+			 * and wants us to directly use the page
+			 * passed in.
+			 */
+			lock_page(mmap_page);
+
+			if (mmap_page->mapping != mapping) {
+				unlock_page(mmap_page);
+				/*
+				 * Sanity check - the locking in
+				 * ocfs2_pagemkwrite() should ensure
+				 * that this code doesn't trigger.
+				 */
+				ret = -EINVAL;
+				mlog_errno(ret);
+				goto out;
+			}
+
+			page_cache_get(mmap_page);
+			wc->w_pages[i] = mmap_page;
+		} else {
+			wc->w_pages[i] = find_or_create_page(mapping, index,
+							     GFP_NOFS);
+			if (!wc->w_pages[i]) {
+				ret = -ENOMEM;
+				mlog_errno(ret);
+				goto out;
+			}
 		}
+
+		if (index == target_index)
+			wc->w_target_page = wc->w_pages[i];
 	}
+out:
+	return ret;
+}
+
+/*
+ * Prepare a single cluster for write one cluster into the file.
+ */
+static int ocfs2_write_cluster(struct address_space *mapping,
+			       u32 phys, unsigned int unwritten,
+			       struct ocfs2_alloc_context *data_ac,
+			       struct ocfs2_alloc_context *meta_ac,
+			       struct ocfs2_write_ctxt *wc, u32 cpos,
+			       loff_t user_pos, unsigned user_len)
+{
+	int ret, i, new, should_zero = 0;
+	u64 v_blkno, p_blkno;
+	struct inode *inode = mapping->host;
+
+	new = phys == 0 ? 1 : 0;
+	if (new || unwritten)
+		should_zero = 1;
 
 	if (new) {
+		u32 tmp_pos;
+
 		/*
 		 * This is safe to call with the page locks - it won't take
 		 * any additional semaphores or cluster locks.
 		 */
-		tmp_pos = wc->w_cpos;
+		tmp_pos = cpos;
 		ret = ocfs2_do_extend_allocation(OCFS2_SB(inode->i_sb), inode,
-						 &tmp_pos, 1, di_bh, handle,
-						 data_ac, meta_ac, NULL);
+						 &tmp_pos, 1, 0, wc->w_di_bh,
+						 wc->w_handle, data_ac,
+						 meta_ac, NULL);
 		/*
 		 * This shouldn't happen because we must have already
 		 * calculated the correct meta data allocation required. The
@@ -1121,159 +1146,433 @@ static ssize_t ocfs2_write(struct file *file, u32 phys, handle_t *handle,
 			mlog_errno(ret);
 			goto out;
 		}
+	} else if (unwritten) {
+		ret = ocfs2_mark_extent_written(inode, wc->w_di_bh,
+						wc->w_handle, cpos, 1, phys,
+						meta_ac, &wc->w_dealloc);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
 	}
 
+	if (should_zero)
+		v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, cpos);
+	else
+		v_blkno = user_pos >> inode->i_sb->s_blocksize_bits;
+
+	/*
+	 * The only reason this should fail is due to an inability to
+	 * find the extent added.
+	 */
 	ret = ocfs2_extent_map_get_blocks(inode, v_blkno, &p_blkno, NULL,
 					  NULL);
 	if (ret < 0) {
-
-		/*
-		 * XXX: Should we go readonly here?
-		 */
-
-		mlog_errno(ret);
+		ocfs2_error(inode->i_sb, "Corrupting extend for inode %llu, "
+			    "at logical block %llu",
+			    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+			    (unsigned long long)v_blkno);
 		goto out;
 	}
 
 	BUG_ON(p_blkno == 0);
 
-	for(i = 0; i < numpages; i++) {
-		ret = ocfs2_write_data_page(inode, handle, &p_blkno, cpages[i],
-					    wc, new);
-		if (ret < 0) {
-			mlog_errno(ret);
-			goto out;
+	for(i = 0; i < wc->w_num_pages; i++) {
+		int tmpret;
+
+		tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
+						      wc->w_pages[i], cpos,
+						      user_pos, user_len,
+						      should_zero);
+		if (tmpret) {
+			mlog_errno(tmpret);
+			if (ret == 0)
+				tmpret = ret;
 		}
-
-		copied += ret;
 	}
 
+	/*
+	 * We only have cleanup to do in case of allocating write.
+	 */
+	if (ret && new)
+		ocfs2_write_failure(inode, wc, user_pos, user_len);
+
 out:
-	for(i = 0; i < numpages; i++) {
-		unlock_page(cpages[i]);
-		mark_page_accessed(cpages[i]);
-		page_cache_release(cpages[i]);
+
+	return ret;
+}
+
+static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
+				       struct ocfs2_alloc_context *data_ac,
+				       struct ocfs2_alloc_context *meta_ac,
+				       struct ocfs2_write_ctxt *wc,
+				       loff_t pos, unsigned len)
+{
+	int ret, i;
+	struct ocfs2_write_cluster_desc *desc;
+
+	for (i = 0; i < wc->w_clen; i++) {
+		desc = &wc->w_desc[i];
+
+		ret = ocfs2_write_cluster(mapping, desc->c_phys,
+					  desc->c_unwritten, data_ac, meta_ac,
+					  wc, desc->c_cpos, pos, len);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
 	}
-	kfree(cpages);
 
-	return copied ? copied : ret;
+	ret = 0;
+out:
+	return ret;
 }
 
-static void ocfs2_write_ctxt_init(struct ocfs2_write_ctxt *wc,
-				  struct ocfs2_super *osb, loff_t pos,
-				  size_t count, ocfs2_page_writer *cb,
-				  void *cb_priv)
+/*
+ * ocfs2_write_end() wants to know which parts of the target page it
+ * should complete the write on. It's easiest to compute them ahead of
+ * time when a more complete view of the write is available.
+ */
+static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
+					struct ocfs2_write_ctxt *wc,
+					loff_t pos, unsigned len, int alloc)
 {
-	wc->w_count = count;
-	wc->w_pos = pos;
-	wc->w_cpos = wc->w_pos >> osb->s_clustersize_bits;
-	wc->w_finished_copy = 0;
+	struct ocfs2_write_cluster_desc *desc;
 
-	if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
-		wc->w_large_pages = 1;
-	else
-		wc->w_large_pages = 0;
+	wc->w_target_from = pos & (PAGE_CACHE_SIZE - 1);
+	wc->w_target_to = wc->w_target_from + len;
 
-	wc->w_write_data_page = cb;
-	wc->w_private = cb_priv;
+	if (alloc == 0)
+		return;
+
+	/*
+	 * Allocating write - we may have different boundaries based
+	 * on page size and cluster size.
+	 *
+	 * NOTE: We can no longer compute one value from the other as
+	 * the actual write length and user provided length may be
+	 * different.
+	 */
+
+	if (wc->w_large_pages) {
+		/*
+		 * We only care about the 1st and last cluster within
+		 * our range and whether they should be zero'd or not. Either
+		 * value may be extended out to the start/end of a
+		 * newly allocated cluster.
+		 */
+		desc = &wc->w_desc[0];
+		if (ocfs2_should_zero_cluster(desc))
+			ocfs2_figure_cluster_boundaries(osb,
+							desc->c_cpos,
+							&wc->w_target_from,
+							NULL);
+
+		desc = &wc->w_desc[wc->w_clen - 1];
+		if (ocfs2_should_zero_cluster(desc))
+			ocfs2_figure_cluster_boundaries(osb,
+							desc->c_cpos,
+							NULL,
+							&wc->w_target_to);
+	} else {
+		wc->w_target_from = 0;
+		wc->w_target_to = PAGE_CACHE_SIZE;
+	}
 }
 
 /*
- * Write a cluster to an inode. The cluster may not be allocated yet,
- * in which case it will be. This only exists for buffered writes -
- * O_DIRECT takes a more "traditional" path through the kernel.
- *
- * The caller is responsible for incrementing pos, written counts, etc
+ * Populate each single-cluster write descriptor in the write context
+ * with information about the i/o to be done.
  *
- * For file systems that don't support sparse files, pre-allocation
- * and page zeroing up until cpos should be done prior to this
- * function call.
- *
- * Callers should be holding i_sem, and the rw cluster lock.
- *
- * Returns the number of user bytes written, or less than zero for
- * error.
+ * Returns the number of clusters that will have to be allocated, as
+ * well as a worst case estimate of the number of extent records that
+ * would have to be created during a write to an unwritten region.
  */
-ssize_t ocfs2_buffered_write_cluster(struct file *file, loff_t pos,
-				     size_t count, ocfs2_page_writer *actor,
-				     void *priv)
+static int ocfs2_populate_write_desc(struct inode *inode,
+				     struct ocfs2_write_ctxt *wc,
+				     unsigned int *clusters_to_alloc,
+				     unsigned int *extents_to_split)
+{
+	int ret;
+	struct ocfs2_write_cluster_desc *desc;
+	unsigned int num_clusters = 0;
+	unsigned int ext_flags = 0;
+	u32 phys = 0;
+	int i;
+
+	*clusters_to_alloc = 0;
+	*extents_to_split = 0;
+
+	for (i = 0; i < wc->w_clen; i++) {
+		desc = &wc->w_desc[i];
+		desc->c_cpos = wc->w_cpos + i;
+
+		if (num_clusters == 0) {
+			/*
+			 * Need to look up the next extent record.
+			 */
+			ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
+						 &num_clusters, &ext_flags);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			/*
+			 * Assume worst case - that we're writing in
+			 * the middle of the extent.
+			 *
+			 * We can assume that the write proceeds from
+			 * left to right, in which case the extent
+			 * insert code is smart enough to coalesce the
+			 * next splits into the previous records created.
+			 */
+			if (ext_flags & OCFS2_EXT_UNWRITTEN)
+				*extents_to_split = *extents_to_split + 2;
+		} else if (phys) {
+			/*
+			 * Only increment phys if it doesn't describe
+			 * a hole.
+			 */
+			phys++;
+		}
+
+		desc->c_phys = phys;
+		if (phys == 0) {
+			desc->c_new = 1;
+			*clusters_to_alloc = *clusters_to_alloc + 1;
+		}
+		if (ext_flags & OCFS2_EXT_UNWRITTEN)
+			desc->c_unwritten = 1;
+
+		num_clusters--;
+	}
+
+	ret = 0;
+out:
+	return ret;
+}
+
+int ocfs2_write_begin_nolock(struct address_space *mapping,
+			     loff_t pos, unsigned len, unsigned flags,
+			     struct page **pagep, void **fsdata,
+			     struct buffer_head *di_bh, struct page *mmap_page)
 {
 	int ret, credits = OCFS2_INODE_UPDATE_CREDITS;
-	ssize_t written = 0;
-	u32 phys;
-	struct inode *inode = file->f_mapping->host;
+	unsigned int clusters_to_alloc, extents_to_split;
+	struct ocfs2_write_ctxt *wc;
+	struct inode *inode = mapping->host;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-	struct buffer_head *di_bh = NULL;
 	struct ocfs2_dinode *di;
 	struct ocfs2_alloc_context *data_ac = NULL;
 	struct ocfs2_alloc_context *meta_ac = NULL;
 	handle_t *handle;
-	struct ocfs2_write_ctxt wc;
-
-	ocfs2_write_ctxt_init(&wc, osb, pos, count, actor, priv);
 
-	ret = ocfs2_meta_lock(inode, &di_bh, 1);
+	ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, di_bh);
 	if (ret) {
 		mlog_errno(ret);
-		goto out;
+		return ret;
 	}
-	di = (struct ocfs2_dinode *)di_bh->b_data;
-
-	/*
-	 * Take alloc sem here to prevent concurrent lookups. That way
-	 * the mapping, zeroing and tree manipulation within
-	 * ocfs2_write() will be safe against ->readpage(). This
-	 * should also serve to lock out allocation from a shared
-	 * writeable region.
-	 */
-	down_write(&OCFS2_I(inode)->ip_alloc_sem);
 
-	ret = ocfs2_get_clusters(inode, wc.w_cpos, &phys, NULL, NULL);
+	ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
+					&extents_to_split);
 	if (ret) {
 		mlog_errno(ret);
-		goto out_meta;
+		goto out;
 	}
 
-	/* phys == 0 means that allocation is required. */
-	if (phys == 0) {
-		ret = ocfs2_lock_allocators(inode, di, 1, &data_ac, &meta_ac);
+	di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
+
+	/*
+	 * We set w_target_from, w_target_to here so that
+	 * ocfs2_write_end() knows which range in the target page to
+	 * write out. An allocation requires that we write the entire
+	 * cluster range.
+	 */
+	if (clusters_to_alloc || extents_to_split) {
+		/*
+		 * XXX: We are stretching the limits of
+		 * ocfs2_lock_allocators(). It greatly over-estimates
+		 * the work to be done.
+		 */
+		ret = ocfs2_lock_allocators(inode, di, clusters_to_alloc,
+					    extents_to_split, &data_ac, &meta_ac);
 		if (ret) {
 			mlog_errno(ret);
-			goto out_meta;
+			goto out;
 		}
 
-		credits = ocfs2_calc_extend_credits(inode->i_sb, di, 1);
-	}
+		credits = ocfs2_calc_extend_credits(inode->i_sb, di,
+						    clusters_to_alloc);
 
-	ret = ocfs2_data_lock(inode, 1);
-	if (ret) {
-		mlog_errno(ret);
-		goto out_meta;
 	}
 
+	ocfs2_set_target_boundaries(osb, wc, pos, len,
+				    clusters_to_alloc + extents_to_split);
+
 	handle = ocfs2_start_trans(osb, credits);
 	if (IS_ERR(handle)) {
 		ret = PTR_ERR(handle);
 		mlog_errno(ret);
-		goto out_data;
+		goto out;
 	}
 
-	written = ocfs2_write(file, phys, handle, di_bh, data_ac,
-			      meta_ac, &wc);
-	if (written < 0) {
-		ret = written;
+	wc->w_handle = handle;
+
+	/*
+	 * We don't want this to fail in ocfs2_write_end(), so do it
+	 * here.
+	 */
+	ret = ocfs2_journal_access(handle, inode, wc->w_di_bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
 	}
 
-	ret = ocfs2_journal_access(handle, inode, di_bh,
-				   OCFS2_JOURNAL_ACCESS_WRITE);
+	/*
+	 * Fill our page array first. That way we've grabbed enough so
+	 * that we can zero and flush if we error after adding the
+	 * extent.
+	 */
+	ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos,
+					 clusters_to_alloc + extents_to_split,
+					 mmap_page);
 	if (ret) {
 		mlog_errno(ret);
 		goto out_commit;
 	}
 
-	pos += written;
+	ret = ocfs2_write_cluster_by_desc(mapping, data_ac, meta_ac, wc, pos,
+					  len);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	if (data_ac)
+		ocfs2_free_alloc_context(data_ac);
+	if (meta_ac)
+		ocfs2_free_alloc_context(meta_ac);
+
+	*pagep = wc->w_target_page;
+	*fsdata = wc;
+	return 0;
+out_commit:
+	ocfs2_commit_trans(osb, handle);
+
+out:
+	ocfs2_free_write_ctxt(wc);
+
+	if (data_ac)
+		ocfs2_free_alloc_context(data_ac);
+	if (meta_ac)
+		ocfs2_free_alloc_context(meta_ac);
+	return ret;
+}
+
+int ocfs2_write_begin(struct file *file, struct address_space *mapping,
+		      loff_t pos, unsigned len, unsigned flags,
+		      struct page **pagep, void **fsdata)
+{
+	int ret;
+	struct buffer_head *di_bh = NULL;
+	struct inode *inode = mapping->host;
+
+	ret = ocfs2_meta_lock(inode, &di_bh, 1);
+	if (ret) {
+		mlog_errno(ret);
+		return ret;
+	}
+
+	/*
+	 * Take alloc sem here to prevent concurrent lookups. That way
+	 * the mapping, zeroing and tree manipulation within
+	 * ocfs2_write() will be safe against ->readpage(). This
+	 * should also serve to lock out allocation from a shared
+	 * writeable region.
+	 */
+	down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+	ret = ocfs2_data_lock(inode, 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_fail;
+	}
+
+	ret = ocfs2_write_begin_nolock(mapping, pos, len, flags, pagep,
+				       fsdata, di_bh, NULL);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_fail_data;
+	}
+
+	brelse(di_bh);
+
+	return 0;
+
+out_fail_data:
+	ocfs2_data_unlock(inode, 1);
+out_fail:
+	up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+	brelse(di_bh);
+	ocfs2_meta_unlock(inode, 1);
+
+	return ret;
+}
+
+int ocfs2_write_end_nolock(struct address_space *mapping,
+			   loff_t pos, unsigned len, unsigned copied,
+			   struct page *page, void *fsdata)
+{
+	int i;
+	unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
+	struct inode *inode = mapping->host;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_write_ctxt *wc = fsdata;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
+	handle_t *handle = wc->w_handle;
+	struct page *tmppage;
+
+	if (unlikely(copied < len)) {
+		if (!PageUptodate(wc->w_target_page))
+			copied = 0;
+
+		ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
+				       start+len);
+	}
+	flush_dcache_page(wc->w_target_page);
+
+	for(i = 0; i < wc->w_num_pages; i++) {
+		tmppage = wc->w_pages[i];
+
+		if (tmppage == wc->w_target_page) {
+			from = wc->w_target_from;
+			to = wc->w_target_to;
+
+			BUG_ON(from > PAGE_CACHE_SIZE ||
+			       to > PAGE_CACHE_SIZE ||
+			       to < from);
+		} else {
+			/*
+			 * Pages adjacent to the target (if any) imply
+			 * a hole-filling write in which case we want
+			 * to flush their entire range.
+			 */
+			from = 0;
+			to = PAGE_CACHE_SIZE;
+		}
+
+		if (ocfs2_should_order_data(inode))
+			walk_page_buffers(wc->w_handle, page_buffers(tmppage),
+					  from, to, NULL,
+					  ocfs2_journal_dirty_data);
+
+		block_commit_write(tmppage, from, to);
+	}
+
+	pos += copied;
 	if (pos > inode->i_size) {
 		i_size_write(inode, pos);
 		mark_inode_dirty(inode);
@@ -1283,29 +1582,31 @@ ssize_t ocfs2_buffered_write_cluster(struct file *file, loff_t pos,
 	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 	di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
 	di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
+	ocfs2_journal_dirty(handle, wc->w_di_bh);
 
-	ret = ocfs2_journal_dirty(handle, di_bh);
-	if (ret)
-		mlog_errno(ret);
-
-out_commit:
 	ocfs2_commit_trans(osb, handle);
 
-out_data:
-	ocfs2_data_unlock(inode, 1);
+	ocfs2_run_deallocs(osb, &wc->w_dealloc);
+
+	ocfs2_free_write_ctxt(wc);
+
+	return copied;
+}
+
+int ocfs2_write_end(struct file *file, struct address_space *mapping,
+		    loff_t pos, unsigned len, unsigned copied,
+		    struct page *page, void *fsdata)
+{
+	int ret;
+	struct inode *inode = mapping->host;
 
-out_meta:
+	ret = ocfs2_write_end_nolock(mapping, pos, len, copied, page, fsdata);
+
+	ocfs2_data_unlock(inode, 1);
 	up_write(&OCFS2_I(inode)->ip_alloc_sem);
 	ocfs2_meta_unlock(inode, 1);
 
-out:
-	brelse(di_bh);
-	if (data_ac)
-		ocfs2_free_alloc_context(data_ac);
-	if (meta_ac)
-		ocfs2_free_alloc_context(meta_ac);
-
-	return written ? written : ret;
+	return ret;
 }
 
 const struct address_space_operations ocfs2_aops = {
diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h
index 45821d479b5..389579bd64e 100644
--- a/fs/ocfs2/aops.h
+++ b/fs/ocfs2/aops.h
@@ -42,57 +42,22 @@ int walk_page_buffers(	handle_t *handle,
 			int (*fn)(	handle_t *handle,
 					struct buffer_head *bh));
 
-struct ocfs2_write_ctxt;
-typedef int (ocfs2_page_writer)(struct inode *, struct ocfs2_write_ctxt *,
-				u64 *, unsigned int *, unsigned int *);
+int ocfs2_write_begin(struct file *file, struct address_space *mapping,
+		      loff_t pos, unsigned len, unsigned flags,
+		      struct page **pagep, void **fsdata);
 
-ssize_t ocfs2_buffered_write_cluster(struct file *file, loff_t pos,
-				     size_t count, ocfs2_page_writer *actor,
-				     void *priv);
+int ocfs2_write_end(struct file *file, struct address_space *mapping,
+		    loff_t pos, unsigned len, unsigned copied,
+		    struct page *page, void *fsdata);
 
-struct ocfs2_write_ctxt {
-	size_t				w_count;
-	loff_t				w_pos;
-	u32				w_cpos;
-	unsigned int			w_finished_copy;
+int ocfs2_write_end_nolock(struct address_space *mapping,
+			   loff_t pos, unsigned len, unsigned copied,
+			   struct page *page, void *fsdata);
 
-	/* This is true if page_size > cluster_size */
-	unsigned int			w_large_pages;
-
-	/* Filler callback and private data */
-	ocfs2_page_writer		*w_write_data_page;
-	void				*w_private;
-
-	/* Only valid for the filler callback */
-	struct page			*w_this_page;
-	unsigned int			w_this_page_new;
-};
-
-struct ocfs2_buffered_write_priv {
-	char				*b_src_buf;
-	const struct iovec		*b_cur_iov; /* Current iovec */
-	size_t				b_cur_off; /* Offset in the
-						    * current iovec */
-};
-int ocfs2_map_and_write_user_data(struct inode *inode,
-				  struct ocfs2_write_ctxt *wc,
-				  u64 *p_blkno,
-				  unsigned int *ret_from,
-				  unsigned int *ret_to);
-
-struct ocfs2_splice_write_priv {
-	struct splice_desc		*s_sd;
-	struct pipe_buffer		*s_buf;
-	struct pipe_inode_info		*s_pipe;
-	/* Neither offset value is ever larger than one page */
-	unsigned int			s_offset;
-	unsigned int			s_buf_offset;
-};
-int ocfs2_map_and_write_splice_data(struct inode *inode,
-				    struct ocfs2_write_ctxt *wc,
-				    u64 *p_blkno,
-				    unsigned int *ret_from,
-				    unsigned int *ret_to);
+int ocfs2_write_begin_nolock(struct address_space *mapping,
+			     loff_t pos, unsigned len, unsigned flags,
+			     struct page **pagep, void **fsdata,
+			     struct buffer_head *di_bh, struct page *mmap_page);
 
 /* all ocfs2_dio_end_io()'s fault */
 #define ocfs2_iocb_is_rw_locked(iocb) \
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 979113479c6..2bd7f788cf3 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1335,6 +1335,7 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
 	ret = wait_event_interruptible(o2hb_steady_queue,
 				atomic_read(&reg->hr_steady_iterations) == 0);
 	if (ret) {
+		/* We got interrupted (hello ptrace!).  Clean up */
 		spin_lock(&o2hb_live_lock);
 		hb_task = reg->hr_task;
 		reg->hr_task = NULL;
@@ -1345,7 +1346,16 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
 		goto out;
 	}
 
-	ret = count;
+	/* Ok, we were woken.  Make sure it wasn't by drop_item() */
+	spin_lock(&o2hb_live_lock);
+	hb_task = reg->hr_task;
+	spin_unlock(&o2hb_live_lock);
+
+	if (hb_task)
+		ret = count;
+	else
+		ret = -EIO;
+
 out:
 	if (filp)
 		fput(filp);
@@ -1523,6 +1533,15 @@ static void o2hb_heartbeat_group_drop_item(struct config_group *group,
 	if (hb_task)
 		kthread_stop(hb_task);
 
+	/*
+	 * If we're racing a dev_write(), we need to wake them.  They will
+	 * check reg->hr_task
+	 */
+	if (atomic_read(&reg->hr_steady_iterations) != 0) {
+		atomic_set(&reg->hr_steady_iterations, 0);
+		wake_up(&o2hb_steady_queue);
+	}
+
 	config_item_put(item);
 }
 
@@ -1665,7 +1684,67 @@ void o2hb_setup_callback(struct o2hb_callback_func *hc,
 }
 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
 
-int o2hb_register_callback(struct o2hb_callback_func *hc)
+static struct o2hb_region *o2hb_find_region(const char *region_uuid)
+{
+	struct o2hb_region *p, *reg = NULL;
+
+	assert_spin_locked(&o2hb_live_lock);
+
+	list_for_each_entry(p, &o2hb_all_regions, hr_all_item) {
+		if (!strcmp(region_uuid, config_item_name(&p->hr_item))) {
+			reg = p;
+			break;
+		}
+	}
+
+	return reg;
+}
+
+static int o2hb_region_get(const char *region_uuid)
+{
+	int ret = 0;
+	struct o2hb_region *reg;
+
+	spin_lock(&o2hb_live_lock);
+
+	reg = o2hb_find_region(region_uuid);
+	if (!reg)
+		ret = -ENOENT;
+	spin_unlock(&o2hb_live_lock);
+
+	if (ret)
+		goto out;
+
+	ret = o2nm_depend_this_node();
+	if (ret)
+		goto out;
+
+	ret = o2nm_depend_item(&reg->hr_item);
+	if (ret)
+		o2nm_undepend_this_node();
+
+out:
+	return ret;
+}
+
+static void o2hb_region_put(const char *region_uuid)
+{
+	struct o2hb_region *reg;
+
+	spin_lock(&o2hb_live_lock);
+
+	reg = o2hb_find_region(region_uuid);
+
+	spin_unlock(&o2hb_live_lock);
+
+	if (reg) {
+		o2nm_undepend_item(&reg->hr_item);
+		o2nm_undepend_this_node();
+	}
+}
+
+int o2hb_register_callback(const char *region_uuid,
+			   struct o2hb_callback_func *hc)
 {
 	struct o2hb_callback_func *tmp;
 	struct list_head *iter;
@@ -1681,6 +1760,12 @@ int o2hb_register_callback(struct o2hb_callback_func *hc)
 		goto out;
 	}
 
+	if (region_uuid) {
+		ret = o2hb_region_get(region_uuid);
+		if (ret)
+			goto out;
+	}
+
 	down_write(&o2hb_callback_sem);
 
 	list_for_each(iter, &hbcall->list) {
@@ -1702,16 +1787,21 @@ out:
 }
 EXPORT_SYMBOL_GPL(o2hb_register_callback);
 
-void o2hb_unregister_callback(struct o2hb_callback_func *hc)
+void o2hb_unregister_callback(const char *region_uuid,
+			      struct o2hb_callback_func *hc)
 {
 	BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
 
 	mlog(ML_HEARTBEAT, "on behalf of %p for funcs %p\n",
 	     __builtin_return_address(0), hc);
 
+	/* XXX Can this happen _with_ a region reference? */
 	if (list_empty(&hc->hc_item))
 		return;
 
+	if (region_uuid)
+		o2hb_region_put(region_uuid);
+
 	down_write(&o2hb_callback_sem);
 
 	list_del_init(&hc->hc_item);
diff --git a/fs/ocfs2/cluster/heartbeat.h b/fs/ocfs2/cluster/heartbeat.h
index cc6d40b3977..35397dd5ecd 100644
--- a/fs/ocfs2/cluster/heartbeat.h
+++ b/fs/ocfs2/cluster/heartbeat.h
@@ -69,8 +69,10 @@ void o2hb_setup_callback(struct o2hb_callback_func *hc,
 			 o2hb_cb_func *func,
 			 void *data,
 			 int priority);
-int o2hb_register_callback(struct o2hb_callback_func *hc);
-void o2hb_unregister_callback(struct o2hb_callback_func *hc);
+int o2hb_register_callback(const char *region_uuid,
+			   struct o2hb_callback_func *hc);
+void o2hb_unregister_callback(const char *region_uuid,
+			      struct o2hb_callback_func *hc);
 void o2hb_fill_node_map(unsigned long *map,
 			unsigned bytes);
 void o2hb_init(void);
diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c
index 9f5ad0f01ce..af2070da308 100644
--- a/fs/ocfs2/cluster/nodemanager.c
+++ b/fs/ocfs2/cluster/nodemanager.c
@@ -900,6 +900,46 @@ static struct o2nm_cluster_group o2nm_cluster_group = {
 	},
 };
 
+int o2nm_depend_item(struct config_item *item)
+{
+	return configfs_depend_item(&o2nm_cluster_group.cs_subsys, item);
+}
+
+void o2nm_undepend_item(struct config_item *item)
+{
+	configfs_undepend_item(&o2nm_cluster_group.cs_subsys, item);
+}
+
+int o2nm_depend_this_node(void)
+{
+	int ret = 0;
+	struct o2nm_node *local_node;
+
+	local_node = o2nm_get_node_by_num(o2nm_this_node());
+	if (!local_node) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = o2nm_depend_item(&local_node->nd_item);
+	o2nm_node_put(local_node);
+
+out:
+	return ret;
+}
+
+void o2nm_undepend_this_node(void)
+{
+	struct o2nm_node *local_node;
+
+	local_node = o2nm_get_node_by_num(o2nm_this_node());
+	BUG_ON(!local_node);
+
+	o2nm_undepend_item(&local_node->nd_item);
+	o2nm_node_put(local_node);
+}
+
+
 static void __exit exit_o2nm(void)
 {
 	if (ocfs2_table_header)
@@ -934,7 +974,7 @@ static int __init init_o2nm(void)
 		goto out_sysctl;
 
 	config_group_init(&o2nm_cluster_group.cs_subsys.su_group);
-	init_MUTEX(&o2nm_cluster_group.cs_subsys.su_sem);
+	mutex_init(&o2nm_cluster_group.cs_subsys.su_mutex);
 	ret = configfs_register_subsystem(&o2nm_cluster_group.cs_subsys);
 	if (ret) {
 		printk(KERN_ERR "nodemanager: Registration returned %d\n", ret);
diff --git a/fs/ocfs2/cluster/nodemanager.h b/fs/ocfs2/cluster/nodemanager.h
index 070522138ae..7c860361b8d 100644
--- a/fs/ocfs2/cluster/nodemanager.h
+++ b/fs/ocfs2/cluster/nodemanager.h
@@ -77,4 +77,9 @@ struct o2nm_node *o2nm_get_node_by_ip(__be32 addr);
 void o2nm_node_get(struct o2nm_node *node);
 void o2nm_node_put(struct o2nm_node *node);
 
+int o2nm_depend_item(struct config_item *item);
+void o2nm_undepend_item(struct config_item *item);
+int o2nm_depend_this_node(void);
+void o2nm_undepend_this_node(void);
+
 #endif /* O2CLUSTER_NODEMANAGER_H */
diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index 0b229a9c795..f0bdfd944c4 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -261,14 +261,12 @@ out:
 
 static void o2net_complete_nodes_nsw(struct o2net_node *nn)
 {
-	struct list_head *iter, *tmp;
+	struct o2net_status_wait *nsw, *tmp;
 	unsigned int num_kills = 0;
-	struct o2net_status_wait *nsw;
 
 	assert_spin_locked(&nn->nn_lock);
 
-	list_for_each_safe(iter, tmp, &nn->nn_status_list) {
-		nsw = list_entry(iter, struct o2net_status_wait, ns_node_item);
+	list_for_each_entry_safe(nsw, tmp, &nn->nn_status_list, ns_node_item) {
 		o2net_complete_nsw_locked(nn, nsw, O2NET_ERR_DIED, 0);
 		num_kills++;
 	}
@@ -764,13 +762,10 @@ EXPORT_SYMBOL_GPL(o2net_register_handler);
 
 void o2net_unregister_handler_list(struct list_head *list)
 {
-	struct list_head *pos, *n;
-	struct o2net_msg_handler *nmh;
+	struct o2net_msg_handler *nmh, *n;
 
 	write_lock(&o2net_handler_lock);
-	list_for_each_safe(pos, n, list) {
-		nmh = list_entry(pos, struct o2net_msg_handler,
-				 nh_unregister_item);
+	list_for_each_entry_safe(nmh, n, list, nh_unregister_item) {
 		mlog(ML_TCP, "unregistering handler func %p type %u key %08x\n",
 		     nmh->nh_func, nmh->nh_msg_type, nmh->nh_key);
 		rb_erase(&nmh->nh_node, &o2net_handler_tree);
@@ -1638,8 +1633,8 @@ static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
 
 void o2net_unregister_hb_callbacks(void)
 {
-	o2hb_unregister_callback(&o2net_hb_up);
-	o2hb_unregister_callback(&o2net_hb_down);
+	o2hb_unregister_callback(NULL, &o2net_hb_up);
+	o2hb_unregister_callback(NULL, &o2net_hb_down);
 }
 
 int o2net_register_hb_callbacks(void)
@@ -1651,9 +1646,9 @@ int o2net_register_hb_callbacks(void)
 	o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
 			    o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
 
-	ret = o2hb_register_callback(&o2net_hb_up);
+	ret = o2hb_register_callback(NULL, &o2net_hb_up);
 	if (ret == 0)
-		ret = o2hb_register_callback(&o2net_hb_down);
+		ret = o2hb_register_callback(NULL, &o2net_hb_down);
 
 	if (ret)
 		o2net_unregister_hb_callbacks();
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index c441ef1f2ba..0d5fdde959c 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -368,7 +368,7 @@ int ocfs2_do_extend_dir(struct super_block *sb,
 		u32 offset = OCFS2_I(dir)->ip_clusters;
 
 		status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, &offset,
-						    1, parent_fe_bh, handle,
+						    1, 0, parent_fe_bh, handle,
 						    data_ac, meta_ac, NULL);
 		BUG_ON(status == -EAGAIN);
 		if (status < 0) {
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index d836b98dd99..6954565b8cc 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -1128,8 +1128,8 @@ bail:
 
 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
 {
-	o2hb_unregister_callback(&dlm->dlm_hb_up);
-	o2hb_unregister_callback(&dlm->dlm_hb_down);
+	o2hb_unregister_callback(NULL, &dlm->dlm_hb_up);
+	o2hb_unregister_callback(NULL, &dlm->dlm_hb_down);
 	o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
 }
 
@@ -1141,13 +1141,13 @@ static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
 
 	o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
 			    dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
-	status = o2hb_register_callback(&dlm->dlm_hb_down);
+	status = o2hb_register_callback(NULL, &dlm->dlm_hb_down);
 	if (status)
 		goto bail;
 
 	o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
 			    dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
-	status = o2hb_register_callback(&dlm->dlm_hb_up);
+	status = o2hb_register_callback(NULL, &dlm->dlm_hb_up);
 	if (status)
 		goto bail;
 
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 6edffca99d9..65b2b9b9268 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -192,25 +192,20 @@ static void dlm_print_one_mle(struct dlm_master_list_entry *mle)
 static void dlm_dump_mles(struct dlm_ctxt *dlm)
 {
 	struct dlm_master_list_entry *mle;
-	struct list_head *iter;
 	
 	mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
 	spin_lock(&dlm->master_lock);
-	list_for_each(iter, &dlm->master_list) {
-		mle = list_entry(iter, struct dlm_master_list_entry, list);
+	list_for_each_entry(mle, &dlm->master_list, list)
 		dlm_print_one_mle(mle);
-	}
 	spin_unlock(&dlm->master_lock);
 }
 
 int dlm_dump_all_mles(const char __user *data, unsigned int len)
 {
-	struct list_head *iter;
 	struct dlm_ctxt *dlm;
 
 	spin_lock(&dlm_domain_lock);
-	list_for_each(iter, &dlm_domains) {
-		dlm = list_entry (iter, struct dlm_ctxt, list);
+	list_for_each_entry(dlm, &dlm_domains, list) {
 		mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
 		dlm_dump_mles(dlm);
 	}
@@ -454,12 +449,10 @@ static int dlm_find_mle(struct dlm_ctxt *dlm,
 			char *name, unsigned int namelen)
 {
 	struct dlm_master_list_entry *tmpmle;
-	struct list_head *iter;
 
 	assert_spin_locked(&dlm->master_lock);
 
-	list_for_each(iter, &dlm->master_list) {
-		tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
+	list_for_each_entry(tmpmle, &dlm->master_list, list) {
 		if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
 			continue;
 		dlm_get_mle(tmpmle);
@@ -472,13 +465,10 @@ static int dlm_find_mle(struct dlm_ctxt *dlm,
 void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
 {
 	struct dlm_master_list_entry *mle;
-	struct list_head *iter;
 
 	assert_spin_locked(&dlm->spinlock);
 	
-	list_for_each(iter, &dlm->mle_hb_events) {
-		mle = list_entry(iter, struct dlm_master_list_entry, 
-				 hb_events);
+	list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
 		if (node_up)
 			dlm_mle_node_up(dlm, mle, NULL, idx);
 		else
@@ -2434,7 +2424,7 @@ static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
 	int ret;
 	int i;
 	int count = 0;
-	struct list_head *queue, *iter;
+	struct list_head *queue;
 	struct dlm_lock *lock;
 
 	assert_spin_locked(&res->spinlock);
@@ -2453,8 +2443,7 @@ static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
 	ret = 0;
 	queue = &res->granted;
 	for (i = 0; i < 3; i++) {
-		list_for_each(iter, queue) {
-			lock = list_entry(iter, struct dlm_lock, list);
+		list_for_each_entry(lock, queue, list) {
 			++count;
 			if (lock->ml.node == dlm->node_num) {
 				mlog(0, "found a lock owned by this node still "
@@ -2923,18 +2912,16 @@ again:
 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
 				      struct dlm_lock_resource *res)
 {
-	struct list_head *iter, *iter2;
 	struct list_head *queue = &res->granted;
 	int i, bit;
-	struct dlm_lock *lock;
+	struct dlm_lock *lock, *next;
 
 	assert_spin_locked(&res->spinlock);
 
 	BUG_ON(res->owner == dlm->node_num);
 
 	for (i=0; i<3; i++) {
-		list_for_each_safe(iter, iter2, queue) {
-			lock = list_entry (iter, struct dlm_lock, list);
+		list_for_each_entry_safe(lock, next, queue, list) {
 			if (lock->ml.node != dlm->node_num) {
 				mlog(0, "putting lock for node %u\n",
 				     lock->ml.node);
@@ -2976,7 +2963,6 @@ static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
 {
 	int i;
 	struct list_head *queue = &res->granted;
-	struct list_head *iter;
 	struct dlm_lock *lock;
 	int nodenum;
 
@@ -2984,10 +2970,9 @@ static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
 
 	spin_lock(&res->spinlock);
 	for (i=0; i<3; i++) {
-		list_for_each(iter, queue) {
+		list_for_each_entry(lock, queue, list) {
 			/* up to the caller to make sure this node
 			 * is alive */
-			lock = list_entry (iter, struct dlm_lock, list);
 			if (lock->ml.node != dlm->node_num) {
 				spin_unlock(&res->spinlock);
 				return lock->ml.node;
@@ -3234,8 +3219,7 @@ static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
 
 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
 {
-	struct list_head *iter, *iter2;
-	struct dlm_master_list_entry *mle;
+	struct dlm_master_list_entry *mle, *next;
 	struct dlm_lock_resource *res;
 	unsigned int hash;
 
@@ -3245,9 +3229,7 @@ top:
 
 	/* clean the master list */
 	spin_lock(&dlm->master_lock);
-	list_for_each_safe(iter, iter2, &dlm->master_list) {
-		mle = list_entry(iter, struct dlm_master_list_entry, list);
-
+	list_for_each_entry_safe(mle, next, &dlm->master_list, list) {
 		BUG_ON(mle->type != DLM_MLE_BLOCK &&
 		       mle->type != DLM_MLE_MASTER &&
 		       mle->type != DLM_MLE_MIGRATION);
diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
index 671c4ed58ee..a2c33160bfd 100644
--- a/fs/ocfs2/dlm/dlmrecovery.c
+++ b/fs/ocfs2/dlm/dlmrecovery.c
@@ -158,8 +158,7 @@ void dlm_dispatch_work(struct work_struct *work)
 	struct dlm_ctxt *dlm =
 		container_of(work, struct dlm_ctxt, dispatched_work);
 	LIST_HEAD(tmp_list);
-	struct list_head *iter, *iter2;
-	struct dlm_work_item *item;
+	struct dlm_work_item *item, *next;
 	dlm_workfunc_t *workfunc;
 	int tot=0;
 
@@ -167,13 +166,12 @@ void dlm_dispatch_work(struct work_struct *work)
 	list_splice_init(&dlm->work_list, &tmp_list);
 	spin_unlock(&dlm->work_lock);
 
-	list_for_each_safe(iter, iter2, &tmp_list) {
+	list_for_each_entry(item, &tmp_list, list) {
 		tot++;
 	}
 	mlog(0, "%s: work thread has %d work items\n", dlm->name, tot);
 
-	list_for_each_safe(iter, iter2, &tmp_list) {
-		item = list_entry(iter, struct dlm_work_item, list);
+	list_for_each_entry_safe(item, next, &tmp_list, list) {
 		workfunc = item->func;
 		list_del_init(&item->list);
 
@@ -549,7 +547,6 @@ static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node)
 {
 	int status = 0;
 	struct dlm_reco_node_data *ndata;
-	struct list_head *iter;
 	int all_nodes_done;
 	int destroy = 0;
 	int pass = 0;
@@ -567,8 +564,7 @@ static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node)
 
 	/* safe to access the node data list without a lock, since this
 	 * process is the only one to change the list */
-	list_for_each(iter, &dlm->reco.node_data) {
-		ndata = list_entry (iter, struct dlm_reco_node_data, list);
+	list_for_each_entry(ndata, &dlm->reco.node_data, list) {
 		BUG_ON(ndata->state != DLM_RECO_NODE_DATA_INIT);
 		ndata->state = DLM_RECO_NODE_DATA_REQUESTING;
 
@@ -655,9 +651,7 @@ static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node)
 		 * done, or if anyone died */
 		all_nodes_done = 1;
 		spin_lock(&dlm_reco_state_lock);
-		list_for_each(iter, &dlm->reco.node_data) {
-			ndata = list_entry (iter, struct dlm_reco_node_data, list);
-
+		list_for_each_entry(ndata, &dlm->reco.node_data, list) {
 			mlog(0, "checking recovery state of node %u\n",
 			     ndata->node_num);
 			switch (ndata->state) {
@@ -774,16 +768,14 @@ static int dlm_init_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
 
 static void dlm_destroy_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
 {
-	struct list_head *iter, *iter2;
-	struct dlm_reco_node_data *ndata;
+	struct dlm_reco_node_data *ndata, *next;
 	LIST_HEAD(tmplist);
 
 	spin_lock(&dlm_reco_state_lock);
 	list_splice_init(&dlm->reco.node_data, &tmplist);
 	spin_unlock(&dlm_reco_state_lock);
 
-	list_for_each_safe(iter, iter2, &tmplist) {
-		ndata = list_entry (iter, struct dlm_reco_node_data, list);
+	list_for_each_entry_safe(ndata, next, &tmplist, list) {
 		list_del_init(&ndata->list);
 		kfree(ndata);
 	}
@@ -876,7 +868,6 @@ static void dlm_request_all_locks_worker(struct dlm_work_item *item, void *data)
 	struct dlm_lock_resource *res;
 	struct dlm_ctxt *dlm;
 	LIST_HEAD(resources);
-	struct list_head *iter;
 	int ret;
 	u8 dead_node, reco_master;
 	int skip_all_done = 0;
@@ -920,8 +911,7 @@ static void dlm_request_all_locks_worker(struct dlm_work_item *item, void *data)
 
 	/* any errors returned will be due to the new_master dying,
 	 * the dlm_reco_thread should detect this */
-	list_for_each(iter, &resources) {
-		res = list_entry (iter, struct dlm_lock_resource, recovering);
+	list_for_each_entry(res, &resources, recovering) {
 		ret = dlm_send_one_lockres(dlm, res, mres, reco_master,
 				   	DLM_MRES_RECOVERY);
 		if (ret < 0) {
@@ -983,7 +973,6 @@ int dlm_reco_data_done_handler(struct o2net_msg *msg, u32 len, void *data,
 {
 	struct dlm_ctxt *dlm = data;
 	struct dlm_reco_data_done *done = (struct dlm_reco_data_done *)msg->buf;
-	struct list_head *iter;
 	struct dlm_reco_node_data *ndata = NULL;
 	int ret = -EINVAL;
 
@@ -1000,8 +989,7 @@ int dlm_reco_data_done_handler(struct o2net_msg *msg, u32 len, void *data,
 			dlm->reco.dead_node, done->node_idx, dlm->node_num);
 
 	spin_lock(&dlm_reco_state_lock);
-	list_for_each(iter, &dlm->reco.node_data) {
-		ndata = list_entry (iter, struct dlm_reco_node_data, list);
+	list_for_each_entry(ndata, &dlm->reco.node_data, list) {
 		if (ndata->node_num != done->node_idx)
 			continue;
 
@@ -1049,13 +1037,11 @@ static void dlm_move_reco_locks_to_list(struct dlm_ctxt *dlm,
 					struct list_head *list,
 				       	u8 dead_node)
 {
-	struct dlm_lock_resource *res;
-	struct list_head *iter, *iter2;
+	struct dlm_lock_resource *res, *next;
 	struct dlm_lock *lock;
 
 	spin_lock(&dlm->spinlock);
-	list_for_each_safe(iter, iter2, &dlm->reco.resources) {
-		res = list_entry (iter, struct dlm_lock_resource, recovering);
+	list_for_each_entry_safe(res, next, &dlm->reco.resources, recovering) {
 		/* always prune any $RECOVERY entries for dead nodes,
 		 * otherwise hangs can occur during later recovery */
 		if (dlm_is_recovery_lock(res->lockname.name,
@@ -1169,7 +1155,7 @@ static void dlm_init_migratable_lockres(struct dlm_migratable_lockres *mres,
 					u8 flags, u8 master)
 {
 	/* mres here is one full page */
-	memset(mres, 0, PAGE_SIZE);
+	clear_page(mres);
 	mres->lockname_len = namelen;
 	memcpy(mres->lockname, lockname, namelen);
 	mres->num_locks = 0;
@@ -1252,7 +1238,7 @@ int dlm_send_one_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 			 struct dlm_migratable_lockres *mres,
 			 u8 send_to, u8 flags)
 {
-	struct list_head *queue, *iter;
+	struct list_head *queue;
 	int total_locks, i;
 	u64 mig_cookie = 0;
 	struct dlm_lock *lock;
@@ -1278,9 +1264,7 @@ int dlm_send_one_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 	total_locks = 0;
 	for (i=DLM_GRANTED_LIST; i<=DLM_BLOCKED_LIST; i++) {
 		queue = dlm_list_idx_to_ptr(res, i);
-		list_for_each(iter, queue) {
-			lock = list_entry (iter, struct dlm_lock, list);
-
+		list_for_each_entry(lock, queue, list) {
 			/* add another lock. */
 			total_locks++;
 			if (!dlm_add_lock_to_array(lock, mres, i))
@@ -1717,7 +1701,6 @@ static int dlm_process_recovery_data(struct dlm_ctxt *dlm,
 	struct dlm_lockstatus *lksb = NULL;
 	int ret = 0;
 	int i, j, bad;
-	struct list_head *iter;
 	struct dlm_lock *lock = NULL;
 	u8 from = O2NM_MAX_NODES;
 	unsigned int added = 0;
@@ -1755,8 +1738,7 @@ static int dlm_process_recovery_data(struct dlm_ctxt *dlm,
 			spin_lock(&res->spinlock);
 			for (j = DLM_GRANTED_LIST; j <= DLM_BLOCKED_LIST; j++) {
 				tmpq = dlm_list_idx_to_ptr(res, j);
-				list_for_each(iter, tmpq) {
-					lock = list_entry (iter, struct dlm_lock, list);
+				list_for_each_entry(lock, tmpq, list) {
 					if (lock->ml.cookie != ml->cookie)
 						lock = NULL;
 					else
@@ -1930,8 +1912,8 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
 				       struct dlm_lock_resource *res)
 {
 	int i;
-	struct list_head *queue, *iter, *iter2;
-	struct dlm_lock *lock;
+	struct list_head *queue;
+	struct dlm_lock *lock, *next;
 
 	res->state |= DLM_LOCK_RES_RECOVERING;
 	if (!list_empty(&res->recovering)) {
@@ -1947,8 +1929,7 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
 	/* find any pending locks and put them back on proper list */
 	for (i=DLM_BLOCKED_LIST; i>=DLM_GRANTED_LIST; i--) {
 		queue = dlm_list_idx_to_ptr(res, i);
-		list_for_each_safe(iter, iter2, queue) {
-			lock = list_entry (iter, struct dlm_lock, list);
+		list_for_each_entry_safe(lock, next, queue, list) {
 			dlm_lock_get(lock);
 			if (lock->convert_pending) {
 				/* move converting lock back to granted */
@@ -2013,18 +1994,15 @@ static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm,
 					      u8 dead_node, u8 new_master)
 {
 	int i;
-	struct list_head *iter, *iter2;
 	struct hlist_node *hash_iter;
 	struct hlist_head *bucket;
-
-	struct dlm_lock_resource *res;
+	struct dlm_lock_resource *res, *next;
 
 	mlog_entry_void();
 
 	assert_spin_locked(&dlm->spinlock);
 
-	list_for_each_safe(iter, iter2, &dlm->reco.resources) {
-		res = list_entry (iter, struct dlm_lock_resource, recovering);
+	list_for_each_entry_safe(res, next, &dlm->reco.resources, recovering) {
 		if (res->owner == dead_node) {
 			list_del_init(&res->recovering);
 			spin_lock(&res->spinlock);
@@ -2099,7 +2077,7 @@ static inline int dlm_lvb_needs_invalidation(struct dlm_lock *lock, int local)
 static void dlm_revalidate_lvb(struct dlm_ctxt *dlm,
 			       struct dlm_lock_resource *res, u8 dead_node)
 {
-	struct list_head *iter, *queue;
+	struct list_head *queue;
 	struct dlm_lock *lock;
 	int blank_lvb = 0, local = 0;
 	int i;
@@ -2121,8 +2099,7 @@ static void dlm_revalidate_lvb(struct dlm_ctxt *dlm,
 
 	for (i=DLM_GRANTED_LIST; i<=DLM_CONVERTING_LIST; i++) {
 		queue = dlm_list_idx_to_ptr(res, i);
-		list_for_each(iter, queue) {
-			lock = list_entry (iter, struct dlm_lock, list);
+		list_for_each_entry(lock, queue, list) {
 			if (lock->ml.node == search_node) {
 				if (dlm_lvb_needs_invalidation(lock, local)) {
 					/* zero the lksb lvb and lockres lvb */
@@ -2143,8 +2120,7 @@ static void dlm_revalidate_lvb(struct dlm_ctxt *dlm,
 static void dlm_free_dead_locks(struct dlm_ctxt *dlm,
 				struct dlm_lock_resource *res, u8 dead_node)
 {
-	struct list_head *iter, *tmpiter;
-	struct dlm_lock *lock;
+	struct dlm_lock *lock, *next;
 	unsigned int freed = 0;
 
 	/* this node is the lockres master:
@@ -2155,24 +2131,21 @@ static void dlm_free_dead_locks(struct dlm_ctxt *dlm,
 	assert_spin_locked(&res->spinlock);
 
 	/* TODO: check pending_asts, pending_basts here */
-	list_for_each_safe(iter, tmpiter, &res->granted) {
-		lock = list_entry (iter, struct dlm_lock, list);
+	list_for_each_entry_safe(lock, next, &res->granted, list) {
 		if (lock->ml.node == dead_node) {
 			list_del_init(&lock->list);
 			dlm_lock_put(lock);
 			freed++;
 		}
 	}
-	list_for_each_safe(iter, tmpiter, &res->converting) {
-		lock = list_entry (iter, struct dlm_lock, list);
+	list_for_each_entry_safe(lock, next, &res->converting, list) {
 		if (lock->ml.node == dead_node) {
 			list_del_init(&lock->list);
 			dlm_lock_put(lock);
 			freed++;
 		}
 	}
-	list_for_each_safe(iter, tmpiter, &res->blocked) {
-		lock = list_entry (iter, struct dlm_lock, list);
+	list_for_each_entry_safe(lock, next, &res->blocked, list) {
 		if (lock->ml.node == dead_node) {
 			list_del_init(&lock->list);
 			dlm_lock_put(lock);
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index d1bd305ef0d..f71250ed166 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -600,15 +600,13 @@ static inline int ocfs2_highest_compat_lock_level(int level)
 static void lockres_set_flags(struct ocfs2_lock_res *lockres,
 			      unsigned long newflags)
 {
-	struct list_head *pos, *tmp;
-	struct ocfs2_mask_waiter *mw;
+	struct ocfs2_mask_waiter *mw, *tmp;
 
  	assert_spin_locked(&lockres->l_lock);
 
 	lockres->l_flags = newflags;
 
-	list_for_each_safe(pos, tmp, &lockres->l_mask_waiters) {
-		mw = list_entry(pos, struct ocfs2_mask_waiter, mw_item);
+	list_for_each_entry_safe(mw, tmp, &lockres->l_mask_waiters, mw_item) {
 		if ((lockres->l_flags & mw->mw_mask) != mw->mw_goal)
 			continue;
 
diff --git a/fs/ocfs2/endian.h b/fs/ocfs2/endian.h
index f226b220762..ff257628af1 100644
--- a/fs/ocfs2/endian.h
+++ b/fs/ocfs2/endian.h
@@ -32,6 +32,11 @@ static inline void le32_add_cpu(__le32 *var, u32 val)
 	*var = cpu_to_le32(le32_to_cpu(*var) + val);
 }
 
+static inline void le64_add_cpu(__le64 *var, u64 val)
+{
+	*var = cpu_to_le64(le64_to_cpu(*var) + val);
+}
+
 static inline void le32_and_cpu(__le32 *var, u32 val)
 {
 	*var = cpu_to_le32(le32_to_cpu(*var) & val);
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index ba2b2ab1c6e..03c1d365c78 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -109,17 +109,14 @@ static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
  */
 void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 {
-	struct list_head *p, *n;
-	struct ocfs2_extent_map_item *emi;
+	struct ocfs2_extent_map_item *emi, *n;
 	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 	struct ocfs2_extent_map *em = &oi->ip_extent_map;
 	LIST_HEAD(tmp_list);
 	unsigned int range;
 
 	spin_lock(&oi->ip_lock);
-	list_for_each_safe(p, n, &em->em_list) {
-		emi = list_entry(p, struct ocfs2_extent_map_item, ei_list);
-
+	list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
 		if (emi->ei_cpos >= cpos) {
 			/* Full truncate of this record. */
 			list_move(&emi->ei_list, &tmp_list);
@@ -136,8 +133,7 @@ void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 	}
 	spin_unlock(&oi->ip_lock);
 
-	list_for_each_safe(p, n, &tmp_list) {
-		emi = list_entry(p, struct ocfs2_extent_map_item, ei_list);
+	list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
 		list_del(&emi->ei_list);
 		kfree(emi);
 	}
@@ -377,37 +373,6 @@ out:
 	return ret;
 }
 
-/*
- * Return the index of the extent record which contains cluster #v_cluster.
- * -1 is returned if it was not found.
- *
- * Should work fine on interior and exterior nodes.
- */
-static int ocfs2_search_extent_list(struct ocfs2_extent_list *el,
-				    u32 v_cluster)
-{
-	int ret = -1;
-	int i;
-	struct ocfs2_extent_rec *rec;
-	u32 rec_end, rec_start, clusters;
-
-	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
-		rec = &el->l_recs[i];
-
-		rec_start = le32_to_cpu(rec->e_cpos);
-		clusters = ocfs2_rec_clusters(el, rec);
-
-		rec_end = rec_start + clusters;
-
-		if (v_cluster >= rec_start && v_cluster < rec_end) {
-			ret = i;
-			break;
-		}
-	}
-
-	return ret;
-}
-
 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
 		       u32 *p_cluster, u32 *num_clusters,
 		       unsigned int *extent_flags)
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 4979b667571..f04c7aa834c 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -263,6 +263,7 @@ static int ocfs2_orphan_for_truncate(struct ocfs2_super *osb,
 	int status;
 	handle_t *handle;
 	struct ocfs2_dinode *di;
+	u64 cluster_bytes;
 
 	mlog_entry_void();
 
@@ -286,7 +287,9 @@ static int ocfs2_orphan_for_truncate(struct ocfs2_super *osb,
 	/*
 	 * Do this before setting i_size.
 	 */
-	status = ocfs2_zero_tail_for_truncate(inode, handle, new_i_size);
+	cluster_bytes = ocfs2_align_bytes_to_clusters(inode->i_sb, new_i_size);
+	status = ocfs2_zero_range_for_truncate(inode, handle, new_i_size,
+					       cluster_bytes);
 	if (status) {
 		mlog_errno(status);
 		goto out_commit;
@@ -326,9 +329,6 @@ static int ocfs2_truncate_file(struct inode *inode,
 		   (unsigned long long)OCFS2_I(inode)->ip_blkno,
 		   (unsigned long long)new_i_size);
 
-	unmap_mapping_range(inode->i_mapping, new_i_size + PAGE_SIZE - 1, 0, 1);
-	truncate_inode_pages(inode->i_mapping, new_i_size);
-
 	fe = (struct ocfs2_dinode *) di_bh->b_data;
 	if (!OCFS2_IS_VALID_DINODE(fe)) {
 		OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, fe);
@@ -363,16 +363,23 @@ static int ocfs2_truncate_file(struct inode *inode,
 	if (new_i_size == le64_to_cpu(fe->i_size))
 		goto bail;
 
+	down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
 	/* This forces other nodes to sync and drop their pages. Do
 	 * this even if we have a truncate without allocation change -
 	 * ocfs2 cluster sizes can be much greater than page size, so
 	 * we have to truncate them anyway.  */
 	status = ocfs2_data_lock(inode, 1);
 	if (status < 0) {
+		up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
 		mlog_errno(status);
 		goto bail;
 	}
 
+	unmap_mapping_range(inode->i_mapping, new_i_size + PAGE_SIZE - 1, 0, 1);
+	truncate_inode_pages(inode->i_mapping, new_i_size);
+
 	/* alright, we're going to need to do a full blown alloc size
 	 * change. Orphan the inode so that recovery can complete the
 	 * truncate if necessary. This does the task of marking
@@ -399,6 +406,8 @@ static int ocfs2_truncate_file(struct inode *inode,
 bail_unlock_data:
 	ocfs2_data_unlock(inode, 1);
 
+	up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
 bail:
 
 	mlog_exit(status);
@@ -419,6 +428,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
 			       struct inode *inode,
 			       u32 *logical_offset,
 			       u32 clusters_to_add,
+			       int mark_unwritten,
 			       struct buffer_head *fe_bh,
 			       handle_t *handle,
 			       struct ocfs2_alloc_context *data_ac,
@@ -431,9 +441,13 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
 	enum ocfs2_alloc_restarted reason = RESTART_NONE;
 	u32 bit_off, num_bits;
 	u64 block;
+	u8 flags = 0;
 
 	BUG_ON(!clusters_to_add);
 
+	if (mark_unwritten)
+		flags = OCFS2_EXT_UNWRITTEN;
+
 	free_extents = ocfs2_num_free_extents(osb, inode, fe);
 	if (free_extents < 0) {
 		status = free_extents;
@@ -483,7 +497,7 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
 	     num_bits, bit_off, (unsigned long long)OCFS2_I(inode)->ip_blkno);
 	status = ocfs2_insert_extent(osb, handle, inode, fe_bh,
 				     *logical_offset, block, num_bits,
-				     meta_ac);
+				     flags, meta_ac);
 	if (status < 0) {
 		mlog_errno(status);
 		goto leave;
@@ -516,25 +530,31 @@ leave:
  * For a given allocation, determine which allocators will need to be
  * accessed, and lock them, reserving the appropriate number of bits.
  *
- * Called from ocfs2_extend_allocation() for file systems which don't
- * support holes, and from ocfs2_write() for file systems which
- * understand sparse inodes.
+ * Sparse file systems call this from ocfs2_write_begin_nolock()
+ * and ocfs2_allocate_unwritten_extents().
+ *
+ * File systems which don't support holes call this from
+ * ocfs2_extend_allocation().
  */
 int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
-			  u32 clusters_to_add,
+			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,
 			  struct ocfs2_alloc_context **meta_ac)
 {
-	int ret, num_free_extents;
+	int ret = 0, num_free_extents;
+	unsigned int max_recs_needed = clusters_to_add + 2 * extents_to_split;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 
 	*meta_ac = NULL;
-	*data_ac = NULL;
+	if (data_ac)
+		*data_ac = NULL;
+
+	BUG_ON(clusters_to_add != 0 && data_ac == NULL);
 
 	mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u, "
-	     "clusters_to_add = %u\n",
+	     "clusters_to_add = %u, extents_to_split = %u\n",
 	     (unsigned long long)OCFS2_I(inode)->ip_blkno, i_size_read(inode),
-	     le32_to_cpu(di->i_clusters), clusters_to_add);
+	     le32_to_cpu(di->i_clusters), clusters_to_add, extents_to_split);
 
 	num_free_extents = ocfs2_num_free_extents(osb, inode, di);
 	if (num_free_extents < 0) {
@@ -552,9 +572,12 @@ int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
 	 *
 	 * Most of the time we'll only be seeing this 1 cluster at a time
 	 * anyway.
+	 *
+	 * Always lock for any unwritten extents - we might want to
+	 * add blocks during a split.
 	 */
 	if (!num_free_extents ||
-	    (ocfs2_sparse_alloc(osb) && num_free_extents < clusters_to_add)) {
+	    (ocfs2_sparse_alloc(osb) && num_free_extents < max_recs_needed)) {
 		ret = ocfs2_reserve_new_metadata(osb, di, meta_ac);
 		if (ret < 0) {
 			if (ret != -ENOSPC)
@@ -563,6 +586,9 @@ int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
 		}
 	}
 
+	if (clusters_to_add == 0)
+		goto out;
+
 	ret = ocfs2_reserve_clusters(osb, clusters_to_add, data_ac);
 	if (ret < 0) {
 		if (ret != -ENOSPC)
@@ -585,14 +611,13 @@ out:
 	return ret;
 }
 
-static int ocfs2_extend_allocation(struct inode *inode,
-				   u32 clusters_to_add)
+static int __ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
+				     u32 clusters_to_add, int mark_unwritten)
 {
 	int status = 0;
 	int restart_func = 0;
-	int drop_alloc_sem = 0;
 	int credits;
-	u32 prev_clusters, logical_start;
+	u32 prev_clusters;
 	struct buffer_head *bh = NULL;
 	struct ocfs2_dinode *fe = NULL;
 	handle_t *handle = NULL;
@@ -607,7 +632,7 @@ static int ocfs2_extend_allocation(struct inode *inode,
 	 * This function only exists for file systems which don't
 	 * support holes.
 	 */
-	BUG_ON(ocfs2_sparse_alloc(osb));
+	BUG_ON(mark_unwritten && !ocfs2_sparse_alloc(osb));
 
 	status = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &bh,
 				  OCFS2_BH_CACHED, inode);
@@ -623,19 +648,10 @@ static int ocfs2_extend_allocation(struct inode *inode,
 		goto leave;
 	}
 
-	logical_start = OCFS2_I(inode)->ip_clusters;
-
 restart_all:
 	BUG_ON(le32_to_cpu(fe->i_clusters) != OCFS2_I(inode)->ip_clusters);
 
-	/* blocks peope in read/write from reading our allocation
-	 * until we're done changing it. We depend on i_mutex to block
-	 * other extend/truncate calls while we're here. Ordering wrt
-	 * start_trans is important here -- always do it before! */
-	down_write(&OCFS2_I(inode)->ip_alloc_sem);
-	drop_alloc_sem = 1;
-
-	status = ocfs2_lock_allocators(inode, fe, clusters_to_add, &data_ac,
+	status = ocfs2_lock_allocators(inode, fe, clusters_to_add, 0, &data_ac,
 				       &meta_ac);
 	if (status) {
 		mlog_errno(status);
@@ -668,6 +684,7 @@ restarted_transaction:
 					    inode,
 					    &logical_start,
 					    clusters_to_add,
+					    mark_unwritten,
 					    bh,
 					    handle,
 					    data_ac,
@@ -720,10 +737,6 @@ restarted_transaction:
 	     OCFS2_I(inode)->ip_clusters, i_size_read(inode));
 
 leave:
-	if (drop_alloc_sem) {
-		up_write(&OCFS2_I(inode)->ip_alloc_sem);
-		drop_alloc_sem = 0;
-	}
 	if (handle) {
 		ocfs2_commit_trans(osb, handle);
 		handle = NULL;
@@ -749,6 +762,25 @@ leave:
 	return status;
 }
 
+static int ocfs2_extend_allocation(struct inode *inode, u32 logical_start,
+				   u32 clusters_to_add, int mark_unwritten)
+{
+	int ret;
+
+	/*
+	 * The alloc sem blocks peope in read/write from reading our
+	 * allocation until we're done changing it. We depend on
+	 * i_mutex to block other extend/truncate calls while we're
+	 * here.
+	 */
+	down_write(&OCFS2_I(inode)->ip_alloc_sem);
+	ret = __ocfs2_extend_allocation(inode, logical_start, clusters_to_add,
+					mark_unwritten);
+	up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+	return ret;
+}
+
 /* Some parts of this taken from generic_cont_expand, which turned out
  * to be too fragile to do exactly what we need without us having to
  * worry about recursive locking in ->prepare_write() and
@@ -890,7 +922,9 @@ static int ocfs2_extend_file(struct inode *inode,
 	}
 
 	if (clusters_to_add) {
-		ret = ocfs2_extend_allocation(inode, clusters_to_add);
+		ret = ocfs2_extend_allocation(inode,
+					      OCFS2_I(inode)->ip_clusters,
+					      clusters_to_add, 0);
 		if (ret < 0) {
 			mlog_errno(ret);
 			goto out_unlock;
@@ -995,6 +1029,13 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
 		goto bail_unlock;
 	}
 
+	/*
+	 * This will intentionally not wind up calling vmtruncate(),
+	 * since all the work for a size change has been done above.
+	 * Otherwise, we could get into problems with truncate as
+	 * ip_alloc_sem is used there to protect against i_size
+	 * changes.
+	 */
 	status = inode_setattr(inode, attr);
 	if (status < 0) {
 		mlog_errno(status);
@@ -1070,17 +1111,16 @@ out:
 	return ret;
 }
 
-static int ocfs2_write_remove_suid(struct inode *inode)
+static int __ocfs2_write_remove_suid(struct inode *inode,
+				     struct buffer_head *bh)
 {
 	int ret;
-	struct buffer_head *bh = NULL;
-	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 	handle_t *handle;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	struct ocfs2_dinode *di;
 
 	mlog_entry("(Inode %llu, mode 0%o)\n",
-		   (unsigned long long)oi->ip_blkno, inode->i_mode);
+		   (unsigned long long)OCFS2_I(inode)->ip_blkno, inode->i_mode);
 
 	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
 	if (handle == NULL) {
@@ -1089,17 +1129,11 @@ static int ocfs2_write_remove_suid(struct inode *inode)
 		goto out;
 	}
 
-	ret = ocfs2_read_block(osb, oi->ip_blkno, &bh, OCFS2_BH_CACHED, inode);
-	if (ret < 0) {
-		mlog_errno(ret);
-		goto out_trans;
-	}
-
 	ret = ocfs2_journal_access(handle, inode, bh,
 				   OCFS2_JOURNAL_ACCESS_WRITE);
 	if (ret < 0) {
 		mlog_errno(ret);
-		goto out_bh;
+		goto out_trans;
 	}
 
 	inode->i_mode &= ~S_ISUID;
@@ -1112,8 +1146,7 @@ static int ocfs2_write_remove_suid(struct inode *inode)
 	ret = ocfs2_journal_dirty(handle, bh);
 	if (ret < 0)
 		mlog_errno(ret);
-out_bh:
-	brelse(bh);
+
 out_trans:
 	ocfs2_commit_trans(osb, handle);
 out:
@@ -1159,6 +1192,460 @@ out:
 	return ret;
 }
 
+static int ocfs2_write_remove_suid(struct inode *inode)
+{
+	int ret;
+	struct buffer_head *bh = NULL;
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+	ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
+			       oi->ip_blkno, &bh, OCFS2_BH_CACHED, inode);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret =  __ocfs2_write_remove_suid(inode, bh);
+out:
+	brelse(bh);
+	return ret;
+}
+
+/*
+ * Allocate enough extents to cover the region starting at byte offset
+ * start for len bytes. Existing extents are skipped, any extents
+ * added are marked as "unwritten".
+ */
+static int ocfs2_allocate_unwritten_extents(struct inode *inode,
+					    u64 start, u64 len)
+{
+	int ret;
+	u32 cpos, phys_cpos, clusters, alloc_size;
+
+	/*
+	 * We consider both start and len to be inclusive.
+	 */
+	cpos = start >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+	clusters = ocfs2_clusters_for_bytes(inode->i_sb, start + len);
+	clusters -= cpos;
+
+	while (clusters) {
+		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
+					 &alloc_size, NULL);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		/*
+		 * Hole or existing extent len can be arbitrary, so
+		 * cap it to our own allocation request.
+		 */
+		if (alloc_size > clusters)
+			alloc_size = clusters;
+
+		if (phys_cpos) {
+			/*
+			 * We already have an allocation at this
+			 * region so we can safely skip it.
+			 */
+			goto next;
+		}
+
+		ret = __ocfs2_extend_allocation(inode, cpos, alloc_size, 1);
+		if (ret) {
+			if (ret != -ENOSPC)
+				mlog_errno(ret);
+			goto out;
+		}
+
+next:
+		cpos += alloc_size;
+		clusters -= alloc_size;
+	}
+
+	ret = 0;
+out:
+	return ret;
+}
+
+static int __ocfs2_remove_inode_range(struct inode *inode,
+				      struct buffer_head *di_bh,
+				      u32 cpos, u32 phys_cpos, u32 len,
+				      struct ocfs2_cached_dealloc_ctxt *dealloc)
+{
+	int ret;
+	u64 phys_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys_cpos);
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct inode *tl_inode = osb->osb_tl_inode;
+	handle_t *handle;
+	struct ocfs2_alloc_context *meta_ac = NULL;
+	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+
+	ret = ocfs2_lock_allocators(inode, di, 0, 1, NULL, &meta_ac);
+	if (ret) {
+		mlog_errno(ret);
+		return ret;
+	}
+
+	mutex_lock(&tl_inode->i_mutex);
+
+	if (ocfs2_truncate_log_needs_flush(osb)) {
+		ret = __ocfs2_flush_truncate_log(osb);
+		if (ret < 0) {
+			mlog_errno(ret);
+			goto out;
+		}
+	}
+
+	handle = ocfs2_start_trans(osb, OCFS2_REMOVE_EXTENT_CREDITS);
+	if (handle == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_journal_access(handle, inode, di_bh,
+				   OCFS2_JOURNAL_ACCESS_WRITE);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_remove_extent(inode, di_bh, cpos, len, handle, meta_ac,
+				  dealloc);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	OCFS2_I(inode)->ip_clusters -= len;
+	di->i_clusters = cpu_to_le32(OCFS2_I(inode)->ip_clusters);
+
+	ret = ocfs2_journal_dirty(handle, di_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_commit;
+	}
+
+	ret = ocfs2_truncate_log_append(osb, handle, phys_blkno, len);
+	if (ret)
+		mlog_errno(ret);
+
+out_commit:
+	ocfs2_commit_trans(osb, handle);
+out:
+	mutex_unlock(&tl_inode->i_mutex);
+
+	if (meta_ac)
+		ocfs2_free_alloc_context(meta_ac);
+
+	return ret;
+}
+
+/*
+ * Truncate a byte range, avoiding pages within partial clusters. This
+ * preserves those pages for the zeroing code to write to.
+ */
+static void ocfs2_truncate_cluster_pages(struct inode *inode, u64 byte_start,
+					 u64 byte_len)
+{
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	loff_t start, end;
+	struct address_space *mapping = inode->i_mapping;
+
+	start = (loff_t)ocfs2_align_bytes_to_clusters(inode->i_sb, byte_start);
+	end = byte_start + byte_len;
+	end = end & ~(osb->s_clustersize - 1);
+
+	if (start < end) {
+		unmap_mapping_range(mapping, start, end - start, 0);
+		truncate_inode_pages_range(mapping, start, end - 1);
+	}
+}
+
+static int ocfs2_zero_partial_clusters(struct inode *inode,
+				       u64 start, u64 len)
+{
+	int ret = 0;
+	u64 tmpend, end = start + len;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	unsigned int csize = osb->s_clustersize;
+	handle_t *handle;
+
+	/*
+	 * The "start" and "end" values are NOT necessarily part of
+	 * the range whose allocation is being deleted. Rather, this
+	 * is what the user passed in with the request. We must zero
+	 * partial clusters here. There's no need to worry about
+	 * physical allocation - the zeroing code knows to skip holes.
+	 */
+	mlog(0, "byte start: %llu, end: %llu\n",
+	     (unsigned long long)start, (unsigned long long)end);
+
+	/*
+	 * If both edges are on a cluster boundary then there's no
+	 * zeroing required as the region is part of the allocation to
+	 * be truncated.
+	 */
+	if ((start & (csize - 1)) == 0 && (end & (csize - 1)) == 0)
+		goto out;
+
+	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+	if (handle == NULL) {
+		ret = -ENOMEM;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * We want to get the byte offset of the end of the 1st cluster.
+	 */
+	tmpend = (u64)osb->s_clustersize + (start & ~(osb->s_clustersize - 1));
+	if (tmpend > end)
+		tmpend = end;
+
+	mlog(0, "1st range: start: %llu, tmpend: %llu\n",
+	     (unsigned long long)start, (unsigned long long)tmpend);
+
+	ret = ocfs2_zero_range_for_truncate(inode, handle, start, tmpend);
+	if (ret)
+		mlog_errno(ret);
+
+	if (tmpend < end) {
+		/*
+		 * This may make start and end equal, but the zeroing
+		 * code will skip any work in that case so there's no
+		 * need to catch it up here.
+		 */
+		start = end & ~(osb->s_clustersize - 1);
+
+		mlog(0, "2nd range: start: %llu, end: %llu\n",
+		     (unsigned long long)start, (unsigned long long)end);
+
+		ret = ocfs2_zero_range_for_truncate(inode, handle, start, end);
+		if (ret)
+			mlog_errno(ret);
+	}
+
+	ocfs2_commit_trans(osb, handle);
+out:
+	return ret;
+}
+
+static int ocfs2_remove_inode_range(struct inode *inode,
+				    struct buffer_head *di_bh, u64 byte_start,
+				    u64 byte_len)
+{
+	int ret = 0;
+	u32 trunc_start, trunc_len, cpos, phys_cpos, alloc_size;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_cached_dealloc_ctxt dealloc;
+
+	ocfs2_init_dealloc_ctxt(&dealloc);
+
+	if (byte_len == 0)
+		return 0;
+
+	trunc_start = ocfs2_clusters_for_bytes(osb->sb, byte_start);
+	trunc_len = (byte_start + byte_len) >> osb->s_clustersize_bits;
+	if (trunc_len >= trunc_start)
+		trunc_len -= trunc_start;
+	else
+		trunc_len = 0;
+
+	mlog(0, "Inode: %llu, start: %llu, len: %llu, cstart: %u, clen: %u\n",
+	     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+	     (unsigned long long)byte_start,
+	     (unsigned long long)byte_len, trunc_start, trunc_len);
+
+	ret = ocfs2_zero_partial_clusters(inode, byte_start, byte_len);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	cpos = trunc_start;
+	while (trunc_len) {
+		ret = ocfs2_get_clusters(inode, cpos, &phys_cpos,
+					 &alloc_size, NULL);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (alloc_size > trunc_len)
+			alloc_size = trunc_len;
+
+		/* Only do work for non-holes */
+		if (phys_cpos != 0) {
+			ret = __ocfs2_remove_inode_range(inode, di_bh, cpos,
+							 phys_cpos, alloc_size,
+							 &dealloc);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+		}
+
+		cpos += alloc_size;
+		trunc_len -= alloc_size;
+	}
+
+	ocfs2_truncate_cluster_pages(inode, byte_start, byte_len);
+
+out:
+	ocfs2_schedule_truncate_log_flush(osb, 1);
+	ocfs2_run_deallocs(osb, &dealloc);
+
+	return ret;
+}
+
+/*
+ * Parts of this function taken from xfs_change_file_space()
+ */
+int ocfs2_change_file_space(struct file *file, unsigned int cmd,
+			    struct ocfs2_space_resv *sr)
+{
+	int ret;
+	s64 llen;
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct buffer_head *di_bh = NULL;
+	handle_t *handle;
+	unsigned long long max_off = ocfs2_max_file_offset(inode->i_sb->s_blocksize_bits);
+
+	if ((cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) &&
+	    !ocfs2_writes_unwritten_extents(osb))
+		return -ENOTTY;
+	else if ((cmd == OCFS2_IOC_UNRESVSP || cmd == OCFS2_IOC_UNRESVSP64) &&
+		 !ocfs2_sparse_alloc(osb))
+		return -ENOTTY;
+
+	if (!S_ISREG(inode->i_mode))
+		return -EINVAL;
+
+	if (!(file->f_mode & FMODE_WRITE))
+		return -EBADF;
+
+	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
+		return -EROFS;
+
+	mutex_lock(&inode->i_mutex);
+
+	/*
+	 * This prevents concurrent writes on other nodes
+	 */
+	ret = ocfs2_rw_lock(inode, 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_meta_lock(inode, &di_bh, 1);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_rw_unlock;
+	}
+
+	if (inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
+		ret = -EPERM;
+		goto out_meta_unlock;
+	}
+
+	switch (sr->l_whence) {
+	case 0: /*SEEK_SET*/
+		break;
+	case 1: /*SEEK_CUR*/
+		sr->l_start += file->f_pos;
+		break;
+	case 2: /*SEEK_END*/
+		sr->l_start += i_size_read(inode);
+		break;
+	default:
+		ret = -EINVAL;
+		goto out_meta_unlock;
+	}
+	sr->l_whence = 0;
+
+	llen = sr->l_len > 0 ? sr->l_len - 1 : sr->l_len;
+
+	if (sr->l_start < 0
+	    || sr->l_start > max_off
+	    || (sr->l_start + llen) < 0
+	    || (sr->l_start + llen) > max_off) {
+		ret = -EINVAL;
+		goto out_meta_unlock;
+	}
+
+	if (cmd == OCFS2_IOC_RESVSP || cmd == OCFS2_IOC_RESVSP64) {
+		if (sr->l_len <= 0) {
+			ret = -EINVAL;
+			goto out_meta_unlock;
+		}
+	}
+
+	if (should_remove_suid(file->f_path.dentry)) {
+		ret = __ocfs2_write_remove_suid(inode, di_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_meta_unlock;
+		}
+	}
+
+	down_write(&OCFS2_I(inode)->ip_alloc_sem);
+	switch (cmd) {
+	case OCFS2_IOC_RESVSP:
+	case OCFS2_IOC_RESVSP64:
+		/*
+		 * This takes unsigned offsets, but the signed ones we
+		 * pass have been checked against overflow above.
+		 */
+		ret = ocfs2_allocate_unwritten_extents(inode, sr->l_start,
+						       sr->l_len);
+		break;
+	case OCFS2_IOC_UNRESVSP:
+	case OCFS2_IOC_UNRESVSP64:
+		ret = ocfs2_remove_inode_range(inode, di_bh, sr->l_start,
+					       sr->l_len);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+	up_write(&OCFS2_I(inode)->ip_alloc_sem);
+	if (ret) {
+		mlog_errno(ret);
+		goto out_meta_unlock;
+	}
+
+	/*
+	 * We update c/mtime for these changes
+	 */
+	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		mlog_errno(ret);
+		goto out_meta_unlock;
+	}
+
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+	ret = ocfs2_mark_inode_dirty(handle, inode, di_bh);
+	if (ret < 0)
+		mlog_errno(ret);
+
+	ocfs2_commit_trans(osb, handle);
+
+out_meta_unlock:
+	brelse(di_bh);
+	ocfs2_meta_unlock(inode, 1);
+out_rw_unlock:
+	ocfs2_rw_unlock(inode, 1);
+
+	mutex_unlock(&inode->i_mutex);
+out:
+	return ret;
+}
+
 static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
 					 loff_t *ppos,
 					 size_t count,
@@ -1329,15 +1816,16 @@ ocfs2_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes)
 	*basep = base;
 }
 
-static struct page * ocfs2_get_write_source(struct ocfs2_buffered_write_priv *bp,
+static struct page * ocfs2_get_write_source(char **ret_src_buf,
 					    const struct iovec *cur_iov,
 					    size_t iov_offset)
 {
 	int ret;
-	char *buf;
+	char *buf = cur_iov->iov_base + iov_offset;
 	struct page *src_page = NULL;
+	unsigned long off;
 
-	buf = cur_iov->iov_base + iov_offset;
+	off = (unsigned long)(buf) & ~PAGE_CACHE_MASK;
 
 	if (!segment_eq(get_fs(), KERNEL_DS)) {
 		/*
@@ -1349,18 +1837,17 @@ static struct page * ocfs2_get_write_source(struct ocfs2_buffered_write_priv *bp
 				     (unsigned long)buf & PAGE_CACHE_MASK, 1,
 				     0, 0, &src_page, NULL);
 		if (ret == 1)
-			bp->b_src_buf = kmap(src_page);
+			*ret_src_buf = kmap(src_page) + off;
 		else
 			src_page = ERR_PTR(-EFAULT);
 	} else {
-		bp->b_src_buf = buf;
+		*ret_src_buf = buf;
 	}
 
 	return src_page;
 }
 
-static void ocfs2_put_write_source(struct ocfs2_buffered_write_priv *bp,
-				   struct page *page)
+static void ocfs2_put_write_source(struct page *page)
 {
 	if (page) {
 		kunmap(page);
@@ -1376,10 +1863,12 @@ static ssize_t ocfs2_file_buffered_write(struct file *file, loff_t *ppos,
 {
 	int ret = 0;
 	ssize_t copied, total = 0;
-	size_t iov_offset = 0;
+	size_t iov_offset = 0, bytes;
+	loff_t pos;
 	const struct iovec *cur_iov = iov;
-	struct ocfs2_buffered_write_priv bp;
-	struct page *page;
+	struct page *user_page, *page;
+	char *buf, *dst;
+	void *fsdata;
 
 	/*
 	 * handle partial DIO write.  Adjust cur_iov if needed.
@@ -1387,21 +1876,38 @@ static ssize_t ocfs2_file_buffered_write(struct file *file, loff_t *ppos,
 	ocfs2_set_next_iovec(&cur_iov, &iov_offset, o_direct_written);
 
 	do {
-		bp.b_cur_off = iov_offset;
-		bp.b_cur_iov = cur_iov;
+		pos = *ppos;
 
-		page = ocfs2_get_write_source(&bp, cur_iov, iov_offset);
-		if (IS_ERR(page)) {
-			ret = PTR_ERR(page);
+		user_page = ocfs2_get_write_source(&buf, cur_iov, iov_offset);
+		if (IS_ERR(user_page)) {
+			ret = PTR_ERR(user_page);
 			goto out;
 		}
 
-		copied = ocfs2_buffered_write_cluster(file, *ppos, count,
-						      ocfs2_map_and_write_user_data,
-						      &bp);
+		/* Stay within our page boundaries */
+		bytes = min((PAGE_CACHE_SIZE - ((unsigned long)pos & ~PAGE_CACHE_MASK)),
+			    (PAGE_CACHE_SIZE - ((unsigned long)buf & ~PAGE_CACHE_MASK)));
+		/* Stay within the vector boundary */
+		bytes = min_t(size_t, bytes, cur_iov->iov_len - iov_offset);
+		/* Stay within count */
+		bytes = min(bytes, count);
+
+		page = NULL;
+		ret = ocfs2_write_begin(file, file->f_mapping, pos, bytes, 0,
+					&page, &fsdata);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
 
-		ocfs2_put_write_source(&bp, page);
+		dst = kmap_atomic(page, KM_USER0);
+		memcpy(dst + (pos & (PAGE_CACHE_SIZE - 1)), buf, bytes);
+		kunmap_atomic(dst, KM_USER0);
+		flush_dcache_page(page);
+		ocfs2_put_write_source(user_page);
 
+		copied = ocfs2_write_end(file, file->f_mapping, pos, bytes,
+					 bytes, page, fsdata);
 		if (copied < 0) {
 			mlog_errno(copied);
 			ret = copied;
@@ -1409,7 +1915,7 @@ static ssize_t ocfs2_file_buffered_write(struct file *file, loff_t *ppos,
 		}
 
 		total += copied;
-		*ppos = *ppos + copied;
+		*ppos = pos + copied;
 		count -= copied;
 
 		ocfs2_set_next_iovec(&cur_iov, &iov_offset, copied);
@@ -1579,52 +2085,46 @@ static int ocfs2_splice_write_actor(struct pipe_inode_info *pipe,
 				    struct pipe_buffer *buf,
 				    struct splice_desc *sd)
 {
-	int ret, count, total = 0;
+	int ret, count;
 	ssize_t copied = 0;
-	struct ocfs2_splice_write_priv sp;
+	struct file *file = sd->u.file;
+	unsigned int offset;
+	struct page *page = NULL;
+	void *fsdata;
+	char *src, *dst;
 
 	ret = buf->ops->confirm(pipe, buf);
 	if (ret)
 		goto out;
 
-	sp.s_sd = sd;
-	sp.s_buf = buf;
-	sp.s_pipe = pipe;
-	sp.s_offset = sd->pos & ~PAGE_CACHE_MASK;
-	sp.s_buf_offset = buf->offset;
-
+	offset = sd->pos & ~PAGE_CACHE_MASK;
 	count = sd->len;
-	if (count + sp.s_offset > PAGE_CACHE_SIZE)
-		count = PAGE_CACHE_SIZE - sp.s_offset;
+	if (count + offset > PAGE_CACHE_SIZE)
+		count = PAGE_CACHE_SIZE - offset;
 
-	do {
-		/*
-		 * splice wants us to copy up to one page at a
-		 * time. For pagesize > cluster size, this means we
-		 * might enter ocfs2_buffered_write_cluster() more
-		 * than once, so keep track of our progress here.
-		 */
-		copied = ocfs2_buffered_write_cluster(sd->u.file,
-						      (loff_t)sd->pos + total,
-						      count,
-						      ocfs2_map_and_write_splice_data,
-						      &sp);
-		if (copied < 0) {
-			mlog_errno(copied);
-			ret = copied;
-			goto out;
-		}
+	ret = ocfs2_write_begin(file, file->f_mapping, sd->pos, count, 0,
+				&page, &fsdata);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
 
-		count -= copied;
-		sp.s_offset += copied;
-		sp.s_buf_offset += copied;
-		total += copied;
-	} while (count);
+	src = buf->ops->map(pipe, buf, 1);
+	dst = kmap_atomic(page, KM_USER1);
+	memcpy(dst + offset, src + buf->offset, count);
+	kunmap_atomic(page, KM_USER1);
+	buf->ops->unmap(pipe, buf, src);
 
-	ret = 0;
+	copied = ocfs2_write_end(file, file->f_mapping, sd->pos, count, count,
+				 page, fsdata);
+	if (copied < 0) {
+		mlog_errno(copied);
+		ret = copied;
+		goto out;
+	}
 out:
 
-	return total ? total : ret;
+	return copied ? copied : ret;
 }
 
 static ssize_t __ocfs2_file_splice_write(struct pipe_inode_info *pipe,
diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index a4dd1fa1822..36fe27f268e 100644
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -39,15 +39,16 @@ enum ocfs2_alloc_restarted {
 };
 int ocfs2_do_extend_allocation(struct ocfs2_super *osb,
 			       struct inode *inode,
-			       u32 *cluster_start,
+			       u32 *logical_offset,
 			       u32 clusters_to_add,
+			       int mark_unwritten,
 			       struct buffer_head *fe_bh,
 			       handle_t *handle,
 			       struct ocfs2_alloc_context *data_ac,
 			       struct ocfs2_alloc_context *meta_ac,
-			       enum ocfs2_alloc_restarted *reason);
+			       enum ocfs2_alloc_restarted *reason_ret);
 int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di,
-			  u32 clusters_to_add,
+			  u32 clusters_to_add, u32 extents_to_split,
 			  struct ocfs2_alloc_context **data_ac,
 			  struct ocfs2_alloc_context **meta_ac);
 int ocfs2_setattr(struct dentry *dentry, struct iattr *attr);
@@ -61,4 +62,7 @@ int ocfs2_should_update_atime(struct inode *inode,
 int ocfs2_update_inode_atime(struct inode *inode,
 			     struct buffer_head *bh);
 
+int ocfs2_change_file_space(struct file *file, unsigned int cmd,
+			    struct ocfs2_space_resv *sr);
+
 #endif /* OCFS2_FILE_H */
diff --git a/fs/ocfs2/heartbeat.c b/fs/ocfs2/heartbeat.c
index b25ef63781b..352eb4a13f9 100644
--- a/fs/ocfs2/heartbeat.c
+++ b/fs/ocfs2/heartbeat.c
@@ -157,16 +157,16 @@ int ocfs2_register_hb_callbacks(struct ocfs2_super *osb)
 	if (ocfs2_mount_local(osb))
 		return 0;
 
-	status = o2hb_register_callback(&osb->osb_hb_down);
+	status = o2hb_register_callback(osb->uuid_str, &osb->osb_hb_down);
 	if (status < 0) {
 		mlog_errno(status);
 		goto bail;
 	}
 
-	status = o2hb_register_callback(&osb->osb_hb_up);
+	status = o2hb_register_callback(osb->uuid_str, &osb->osb_hb_up);
 	if (status < 0) {
 		mlog_errno(status);
-		o2hb_unregister_callback(&osb->osb_hb_down);
+		o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_down);
 	}
 
 bail:
@@ -178,8 +178,8 @@ void ocfs2_clear_hb_callbacks(struct ocfs2_super *osb)
 	if (ocfs2_mount_local(osb))
 		return;
 
-	o2hb_unregister_callback(&osb->osb_hb_down);
-	o2hb_unregister_callback(&osb->osb_hb_up);
+	o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_down);
+	o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_up);
 }
 
 void ocfs2_stop_heartbeat(struct ocfs2_super *osb)
diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index f3ad21ad9ae..bd68c3f2afb 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -14,6 +14,7 @@
 #include "ocfs2.h"
 #include "alloc.h"
 #include "dlmglue.h"
+#include "file.h"
 #include "inode.h"
 #include "journal.h"
 
@@ -115,6 +116,7 @@ int ocfs2_ioctl(struct inode * inode, struct file * filp,
 {
 	unsigned int flags;
 	int status;
+	struct ocfs2_space_resv sr;
 
 	switch (cmd) {
 	case OCFS2_IOC_GETFLAGS:
@@ -130,6 +132,14 @@ int ocfs2_ioctl(struct inode * inode, struct file * filp,
 
 		return ocfs2_set_inode_attr(inode, flags,
 			OCFS2_FL_MODIFIABLE);
+	case OCFS2_IOC_RESVSP:
+	case OCFS2_IOC_RESVSP64:
+	case OCFS2_IOC_UNRESVSP:
+	case OCFS2_IOC_UNRESVSP64:
+		if (copy_from_user(&sr, (int __user *) arg, sizeof(sr)))
+			return -EFAULT;
+
+		return ocfs2_change_file_space(filp, cmd, &sr);
 	default:
 		return -ENOTTY;
 	}
@@ -148,6 +158,11 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 	case OCFS2_IOC32_SETFLAGS:
 		cmd = OCFS2_IOC_SETFLAGS;
 		break;
+	case OCFS2_IOC_RESVSP:
+	case OCFS2_IOC_RESVSP64:
+	case OCFS2_IOC_UNRESVSP:
+	case OCFS2_IOC_UNRESVSP64:
+		break;
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index dc118808172..dbfb20bb27e 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -722,8 +722,7 @@ void ocfs2_complete_recovery(struct work_struct *work)
 		container_of(work, struct ocfs2_journal, j_recovery_work);
 	struct ocfs2_super *osb = journal->j_osb;
 	struct ocfs2_dinode *la_dinode, *tl_dinode;
-	struct ocfs2_la_recovery_item *item;
-	struct list_head *p, *n;
+	struct ocfs2_la_recovery_item *item, *n;
 	LIST_HEAD(tmp_la_list);
 
 	mlog_entry_void();
@@ -734,8 +733,7 @@ void ocfs2_complete_recovery(struct work_struct *work)
 	list_splice_init(&journal->j_la_cleanups, &tmp_la_list);
 	spin_unlock(&journal->j_lock);
 
-	list_for_each_safe(p, n, &tmp_la_list) {
-		item = list_entry(p, struct ocfs2_la_recovery_item, lri_list);
+	list_for_each_entry_safe(item, n, &tmp_la_list, lri_list) {
 		list_del_init(&item->lri_list);
 
 		mlog(0, "Complete recovery for slot %d\n", item->lri_slot);
diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
index 3db5de4506d..ce60aab013a 100644
--- a/fs/ocfs2/journal.h
+++ b/fs/ocfs2/journal.h
@@ -289,6 +289,8 @@ int                  ocfs2_journal_dirty_data(handle_t *handle,
 #define OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC (OCFS2_SUBALLOC_FREE 		      \
 					 + OCFS2_TRUNCATE_LOG_UPDATE)
 
+#define OCFS2_REMOVE_EXTENT_CREDITS (OCFS2_TRUNCATE_LOG_UPDATE + OCFS2_INODE_UPDATE_CREDITS)
+
 /* data block for new dir/symlink, 2 for bitmap updates (bitmap fe +
  * bitmap block for the new bit) */
 #define OCFS2_DIR_LINK_ADDITIONAL_CREDITS (1 + 2)
diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index af01158b39f..d79aa12137d 100644
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -37,11 +37,29 @@
 
 #include "ocfs2.h"
 
+#include "aops.h"
 #include "dlmglue.h"
 #include "file.h"
 #include "inode.h"
 #include "mmap.h"
 
+static inline int ocfs2_vm_op_block_sigs(sigset_t *blocked, sigset_t *oldset)
+{
+	/* The best way to deal with signals in the vm path is
+	 * to block them upfront, rather than allowing the
+	 * locking paths to return -ERESTARTSYS. */
+	sigfillset(blocked);
+
+	/* We should technically never get a bad return value
+	 * from sigprocmask */
+	return sigprocmask(SIG_BLOCK, blocked, oldset);
+}
+
+static inline int ocfs2_vm_op_unblock_sigs(sigset_t *oldset)
+{
+	return sigprocmask(SIG_SETMASK, oldset, NULL);
+}
+
 static struct page *ocfs2_nopage(struct vm_area_struct * area,
 				 unsigned long address,
 				 int *type)
@@ -53,14 +71,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area,
 	mlog_entry("(area=%p, address=%lu, type=%p)\n", area, address,
 		   type);
 
-	/* The best way to deal with signals in this path is
-	 * to block them upfront, rather than allowing the
-	 * locking paths to return -ERESTARTSYS. */
-	sigfillset(&blocked);
-
-	/* We should technically never get a bad ret return
-	 * from sigprocmask */
-	ret = sigprocmask(SIG_BLOCK, &blocked, &oldset);
+	ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
 	if (ret < 0) {
 		mlog_errno(ret);
 		goto out;
@@ -68,7 +79,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area,
 
 	page = filemap_nopage(area, address, type);
 
-	ret = sigprocmask(SIG_SETMASK, &oldset, NULL);
+	ret = ocfs2_vm_op_unblock_sigs(&oldset);
 	if (ret < 0)
 		mlog_errno(ret);
 out:
@@ -76,28 +87,136 @@ out:
 	return page;
 }
 
-static struct vm_operations_struct ocfs2_file_vm_ops = {
-	.nopage = ocfs2_nopage,
-};
+static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
+				struct page *page)
+{
+	int ret;
+	struct address_space *mapping = inode->i_mapping;
+	loff_t pos = page->index << PAGE_CACHE_SHIFT;
+	unsigned int len = PAGE_CACHE_SIZE;
+	pgoff_t last_index;
+	struct page *locked_page = NULL;
+	void *fsdata;
+	loff_t size = i_size_read(inode);
 
-int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
+	/*
+	 * Another node might have truncated while we were waiting on
+	 * cluster locks.
+	 */
+	last_index = size >> PAGE_CACHE_SHIFT;
+	if (page->index > last_index) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * The i_size check above doesn't catch the case where nodes
+	 * truncated and then re-extended the file. We'll re-check the
+	 * page mapping after taking the page lock inside of
+	 * ocfs2_write_begin_nolock().
+	 */
+	if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Call ocfs2_write_begin() and ocfs2_write_end() to take
+	 * advantage of the allocation code there. We pass a write
+	 * length of the whole page (chopped to i_size) to make sure
+	 * the whole thing is allocated.
+	 *
+	 * Since we know the page is up to date, we don't have to
+	 * worry about ocfs2_write_begin() skipping some buffer reads
+	 * because the "write" would invalidate their data.
+	 */
+	if (page->index == last_index)
+		len = size & ~PAGE_CACHE_MASK;
+
+	ret = ocfs2_write_begin_nolock(mapping, pos, len, 0, &locked_page,
+				       &fsdata, di_bh, page);
+	if (ret) {
+		if (ret != -ENOSPC)
+			mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
+				     fsdata);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
+	BUG_ON(ret != len);
+	ret = 0;
+out:
+	return ret;
+}
+
+static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct page *page)
 {
-	int ret = 0, lock_level = 0;
-	struct ocfs2_super *osb = OCFS2_SB(file->f_dentry->d_inode->i_sb);
+	struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+	struct buffer_head *di_bh = NULL;
+	sigset_t blocked, oldset;
+	int ret, ret2;
+
+	ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
+	if (ret < 0) {
+		mlog_errno(ret);
+		return ret;
+	}
+
+	/*
+	 * The cluster locks taken will block a truncate from another
+	 * node. Taking the data lock will also ensure that we don't
+	 * attempt page truncation as part of a downconvert.
+	 */
+	ret = ocfs2_meta_lock(inode, &di_bh, 1);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
 
 	/*
-	 * Only support shared writeable mmap for local mounts which
-	 * don't know about holes.
+	 * The alloc sem should be enough to serialize with
+	 * ocfs2_truncate_file() changing i_size as well as any thread
+	 * modifying the inode btree.
 	 */
-	if ((!ocfs2_mount_local(osb) || ocfs2_sparse_alloc(osb)) &&
-	    ((vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_MAYSHARE)) &&
-	    ((vma->vm_flags & VM_WRITE) || (vma->vm_flags & VM_MAYWRITE))) {
-		mlog(0, "disallow shared writable mmaps %lx\n", vma->vm_flags);
-		/* This is -EINVAL because generic_file_readonly_mmap
-		 * returns it in a similar situation. */
-		return -EINVAL;
+	down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+	ret = ocfs2_data_lock(inode, 1);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out_meta_unlock;
 	}
 
+	ret = __ocfs2_page_mkwrite(inode, di_bh, page);
+
+	ocfs2_data_unlock(inode, 1);
+
+out_meta_unlock:
+	up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+	brelse(di_bh);
+	ocfs2_meta_unlock(inode, 1);
+
+out:
+	ret2 = ocfs2_vm_op_unblock_sigs(&oldset);
+	if (ret2 < 0)
+		mlog_errno(ret2);
+
+	return ret;
+}
+
+static struct vm_operations_struct ocfs2_file_vm_ops = {
+	.nopage		= ocfs2_nopage,
+	.page_mkwrite	= ocfs2_page_mkwrite,
+};
+
+int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	int ret = 0, lock_level = 0;
+
 	ret = ocfs2_meta_lock_atime(file->f_dentry->d_inode,
 				    file->f_vfsmnt, &lock_level);
 	if (ret < 0) {
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 36289e6295c..d430fdab16e 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -1674,7 +1674,7 @@ static int ocfs2_symlink(struct inode *dir,
 		u32 offset = 0;
 
 		inode->i_op = &ocfs2_symlink_inode_operations;
-		status = ocfs2_do_extend_allocation(osb, inode, &offset, 1,
+		status = ocfs2_do_extend_allocation(osb, inode, &offset, 1, 0,
 						    new_fe_bh,
 						    handle, data_ac, NULL,
 						    NULL);
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index a860633e833..5cc90a40b3c 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -219,6 +219,7 @@ struct ocfs2_super
 	u16 max_slots;
 	s16 node_num;
 	s16 slot_num;
+	s16 preferred_slot;
 	int s_sectsize_bits;
 	int s_clustersize;
 	int s_clustersize_bits;
@@ -305,6 +306,19 @@ static inline int ocfs2_sparse_alloc(struct ocfs2_super *osb)
 	return 0;
 }
 
+static inline int ocfs2_writes_unwritten_extents(struct ocfs2_super *osb)
+{
+	/*
+	 * Support for sparse files is a pre-requisite
+	 */
+	if (!ocfs2_sparse_alloc(osb))
+		return 0;
+
+	if (osb->s_feature_ro_compat & OCFS2_FEATURE_RO_COMPAT_UNWRITTEN)
+		return 1;
+	return 0;
+}
+
 /* set / clear functions because cluster events can make these happen
  * in parallel so we want the transitions to be atomic. this also
  * means that any future flags osb_flags must be protected by spinlock
diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h
index f0d9eb08547..82f8a75b207 100644
--- a/fs/ocfs2/ocfs2_fs.h
+++ b/fs/ocfs2/ocfs2_fs.h
@@ -88,7 +88,7 @@
 #define OCFS2_FEATURE_COMPAT_SUPP	OCFS2_FEATURE_COMPAT_BACKUP_SB
 #define OCFS2_FEATURE_INCOMPAT_SUPP	(OCFS2_FEATURE_INCOMPAT_LOCAL_MOUNT \
 					 | OCFS2_FEATURE_INCOMPAT_SPARSE_ALLOC)
-#define OCFS2_FEATURE_RO_COMPAT_SUPP	0
+#define OCFS2_FEATURE_RO_COMPAT_SUPP	OCFS2_FEATURE_RO_COMPAT_UNWRITTEN
 
 /*
  * Heartbeat-only devices are missing journals and other files.  The
@@ -116,6 +116,11 @@
  */
 #define OCFS2_FEATURE_COMPAT_BACKUP_SB		0x0001
 
+/*
+ * Unwritten extents support.
+ */
+#define OCFS2_FEATURE_RO_COMPAT_UNWRITTEN	0x0001
+
 /* The byte offset of the first backup block will be 1G.
  * The following will be 4G, 16G, 64G, 256G and 1T.
  */
@@ -170,6 +175,32 @@
 #define OCFS2_IOC32_SETFLAGS	_IOW('f', 2, int)
 
 /*
+ * Space reservation / allocation / free ioctls and argument structure
+ * are designed to be compatible with XFS.
+ *
+ * ALLOCSP* and FREESP* are not and will never be supported, but are
+ * included here for completeness.
+ */
+struct ocfs2_space_resv {
+	__s16		l_type;
+	__s16		l_whence;
+	__s64		l_start;
+	__s64		l_len;		/* len == 0 means until end of file */
+	__s32		l_sysid;
+	__u32		l_pid;
+	__s32		l_pad[4];	/* reserve area			    */
+};
+
+#define OCFS2_IOC_ALLOCSP		_IOW ('X', 10, struct ocfs2_space_resv)
+#define OCFS2_IOC_FREESP		_IOW ('X', 11, struct ocfs2_space_resv)
+#define OCFS2_IOC_RESVSP		_IOW ('X', 40, struct ocfs2_space_resv)
+#define OCFS2_IOC_UNRESVSP	_IOW ('X', 41, struct ocfs2_space_resv)
+#define OCFS2_IOC_ALLOCSP64	_IOW ('X', 36, struct ocfs2_space_resv)
+#define OCFS2_IOC_FREESP64	_IOW ('X', 37, struct ocfs2_space_resv)
+#define OCFS2_IOC_RESVSP64	_IOW ('X', 42, struct ocfs2_space_resv)
+#define OCFS2_IOC_UNRESVSP64	_IOW ('X', 43, struct ocfs2_space_resv)
+
+/*
  * Journal Flags (ocfs2_dinode.id1.journal1.i_flags)
  */
 #define OCFS2_JOURNAL_DIRTY_FL	(0x00000001)	/* Journal needs recovery */
diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index d8b79067dc1..af4882b62cf 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -121,17 +121,25 @@ static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
 	return ret;
 }
 
-static s16 __ocfs2_find_empty_slot(struct ocfs2_slot_info *si)
+static s16 __ocfs2_find_empty_slot(struct ocfs2_slot_info *si, s16 preferred)
 {
 	int i;
 	s16 ret = OCFS2_INVALID_SLOT;
 
+	if (preferred >= 0 && preferred < si->si_num_slots) {
+		if (OCFS2_INVALID_SLOT == si->si_global_node_nums[preferred]) {
+			ret = preferred;
+			goto out;
+		}
+	}
+
 	for(i = 0; i < si->si_num_slots; i++) {
 		if (OCFS2_INVALID_SLOT == si->si_global_node_nums[i]) {
 			ret = (s16) i;
 			break;
 		}
 	}
+out:
 	return ret;
 }
 
@@ -248,7 +256,7 @@ int ocfs2_find_slot(struct ocfs2_super *osb)
 	if (slot == OCFS2_INVALID_SLOT) {
 		/* if no slot yet, then just take 1st available
 		 * one. */
-		slot = __ocfs2_find_empty_slot(si);
+		slot = __ocfs2_find_empty_slot(si, osb->preferred_slot);
 		if (slot == OCFS2_INVALID_SLOT) {
 			spin_unlock(&si->si_lock);
 			mlog(ML_ERROR, "no free slots available!\n");
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index e3437626d18..d9c5c9fcb30 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -98,14 +98,6 @@ static int ocfs2_relink_block_group(handle_t *handle,
 				    u16 chain);
 static inline int ocfs2_block_group_reasonably_empty(struct ocfs2_group_desc *bg,
 						     u32 wanted);
-static int ocfs2_free_suballoc_bits(handle_t *handle,
-				    struct inode *alloc_inode,
-				    struct buffer_head *alloc_bh,
-				    unsigned int start_bit,
-				    u64 bg_blkno,
-				    unsigned int count);
-static inline u64 ocfs2_which_suballoc_group(u64 block,
-					     unsigned int bit);
 static inline u32 ocfs2_desc_bitmap_to_cluster_off(struct inode *inode,
 						   u64 bg_blkno,
 						   u16 bg_bit_off);
@@ -496,13 +488,7 @@ int ocfs2_reserve_new_metadata(struct ocfs2_super *osb,
 
 	(*ac)->ac_bits_wanted = ocfs2_extend_meta_needed(fe);
 	(*ac)->ac_which = OCFS2_AC_USE_META;
-
-#ifndef OCFS2_USE_ALL_METADATA_SUBALLOCATORS
-	slot = 0;
-#else
 	slot = osb->slot_num;
-#endif
-
 	(*ac)->ac_group_search = ocfs2_block_group_search;
 
 	status = ocfs2_reserve_suballoc_bits(osb, (*ac),
@@ -1626,12 +1612,12 @@ bail:
 /*
  * expects the suballoc inode to already be locked.
  */
-static int ocfs2_free_suballoc_bits(handle_t *handle,
-				    struct inode *alloc_inode,
-				    struct buffer_head *alloc_bh,
-				    unsigned int start_bit,
-				    u64 bg_blkno,
-				    unsigned int count)
+int ocfs2_free_suballoc_bits(handle_t *handle,
+			     struct inode *alloc_inode,
+			     struct buffer_head *alloc_bh,
+			     unsigned int start_bit,
+			     u64 bg_blkno,
+			     unsigned int count)
 {
 	int status = 0;
 	u32 tmp_used;
@@ -1703,13 +1689,6 @@ bail:
 	return status;
 }
 
-static inline u64 ocfs2_which_suballoc_group(u64 block, unsigned int bit)
-{
-	u64 group = block - (u64) bit;
-
-	return group;
-}
-
 int ocfs2_free_dinode(handle_t *handle,
 		      struct inode *inode_alloc_inode,
 		      struct buffer_head *inode_alloc_bh,
@@ -1723,19 +1702,6 @@ int ocfs2_free_dinode(handle_t *handle,
 					inode_alloc_bh, bit, bg_blkno, 1);
 }
 
-int ocfs2_free_extent_block(handle_t *handle,
-			    struct inode *eb_alloc_inode,
-			    struct buffer_head *eb_alloc_bh,
-			    struct ocfs2_extent_block *eb)
-{
-	u64 blk = le64_to_cpu(eb->h_blkno);
-	u16 bit = le16_to_cpu(eb->h_suballoc_bit);
-	u64 bg_blkno = ocfs2_which_suballoc_group(blk, bit);
-
-	return ocfs2_free_suballoc_bits(handle, eb_alloc_inode, eb_alloc_bh,
-					bit, bg_blkno, 1);
-}
-
 int ocfs2_free_clusters(handle_t *handle,
 		       struct inode *bitmap_inode,
 		       struct buffer_head *bitmap_bh,
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 1a3c94cb925..f212dc01a84 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -86,20 +86,29 @@ int ocfs2_claim_clusters(struct ocfs2_super *osb,
 			 u32 *cluster_start,
 			 u32 *num_clusters);
 
+int ocfs2_free_suballoc_bits(handle_t *handle,
+			     struct inode *alloc_inode,
+			     struct buffer_head *alloc_bh,
+			     unsigned int start_bit,
+			     u64 bg_blkno,
+			     unsigned int count);
 int ocfs2_free_dinode(handle_t *handle,
 		      struct inode *inode_alloc_inode,
 		      struct buffer_head *inode_alloc_bh,
 		      struct ocfs2_dinode *di);
-int ocfs2_free_extent_block(handle_t *handle,
-			    struct inode *eb_alloc_inode,
-			    struct buffer_head *eb_alloc_bh,
-			    struct ocfs2_extent_block *eb);
 int ocfs2_free_clusters(handle_t *handle,
 			struct inode *bitmap_inode,
 			struct buffer_head *bitmap_bh,
 			u64 start_blk,
 			unsigned int num_clusters);
 
+static inline u64 ocfs2_which_suballoc_group(u64 block, unsigned int bit)
+{
+	u64 group = block - (u64) bit;
+
+	return group;
+}
+
 static inline u32 ocfs2_cluster_from_desc(struct ocfs2_super *osb,
 					  u64 bg_blkno)
 {
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 86b559c7dce..3a5a1ed09ac 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -82,7 +82,8 @@ MODULE_AUTHOR("Oracle");
 MODULE_LICENSE("GPL");
 
 static int ocfs2_parse_options(struct super_block *sb, char *options,
-			       unsigned long *mount_opt, int is_remount);
+			       unsigned long *mount_opt, s16 *slot,
+			       int is_remount);
 static void ocfs2_put_super(struct super_block *sb);
 static int ocfs2_mount_volume(struct super_block *sb);
 static int ocfs2_remount(struct super_block *sb, int *flags, char *data);
@@ -114,8 +115,6 @@ static void ocfs2_write_super(struct super_block *sb);
 static struct inode *ocfs2_alloc_inode(struct super_block *sb);
 static void ocfs2_destroy_inode(struct inode *inode);
 
-static unsigned long long ocfs2_max_file_offset(unsigned int blockshift);
-
 static const struct super_operations ocfs2_sops = {
 	.statfs		= ocfs2_statfs,
 	.alloc_inode	= ocfs2_alloc_inode,
@@ -140,6 +139,7 @@ enum {
 	Opt_data_ordered,
 	Opt_data_writeback,
 	Opt_atime_quantum,
+	Opt_slot,
 	Opt_err,
 };
 
@@ -154,6 +154,7 @@ static match_table_t tokens = {
 	{Opt_data_ordered, "data=ordered"},
 	{Opt_data_writeback, "data=writeback"},
 	{Opt_atime_quantum, "atime_quantum=%u"},
+	{Opt_slot, "preferred_slot=%u"},
 	{Opt_err, NULL}
 };
 
@@ -318,7 +319,7 @@ static void ocfs2_destroy_inode(struct inode *inode)
 /* From xfs_super.c:xfs_max_file_offset
  * Copyright (c) 2000-2004 Silicon Graphics, Inc.
  */
-static unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
+unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
 {
 	unsigned int pagefactor = 1;
 	unsigned int bitshift = BITS_PER_LONG - 1;
@@ -355,9 +356,10 @@ static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
 	int incompat_features;
 	int ret = 0;
 	unsigned long parsed_options;
+	s16 slot;
 	struct ocfs2_super *osb = OCFS2_SB(sb);
 
-	if (!ocfs2_parse_options(sb, data, &parsed_options, 1)) {
+	if (!ocfs2_parse_options(sb, data, &parsed_options, &slot, 1)) {
 		ret = -EINVAL;
 		goto out;
 	}
@@ -534,6 +536,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	struct dentry *root;
 	int status, sector_size;
 	unsigned long parsed_opt;
+	s16 slot;
 	struct inode *inode = NULL;
 	struct ocfs2_super *osb = NULL;
 	struct buffer_head *bh = NULL;
@@ -541,7 +544,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 
 	mlog_entry("%p, %p, %i", sb, data, silent);
 
-	if (!ocfs2_parse_options(sb, data, &parsed_opt, 0)) {
+	if (!ocfs2_parse_options(sb, data, &parsed_opt, &slot, 0)) {
 		status = -EINVAL;
 		goto read_super_error;
 	}
@@ -571,6 +574,7 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
 	brelse(bh);
 	bh = NULL;
 	osb->s_mount_opt = parsed_opt;
+	osb->preferred_slot = slot;
 
 	sb->s_magic = OCFS2_SUPER_MAGIC;
 
@@ -713,6 +717,7 @@ static struct file_system_type ocfs2_fs_type = {
 static int ocfs2_parse_options(struct super_block *sb,
 			       char *options,
 			       unsigned long *mount_opt,
+			       s16 *slot,
 			       int is_remount)
 {
 	int status;
@@ -722,6 +727,7 @@ static int ocfs2_parse_options(struct super_block *sb,
 		   options ? options : "(none)");
 
 	*mount_opt = 0;
+	*slot = OCFS2_INVALID_SLOT;
 
 	if (!options) {
 		status = 1;
@@ -782,6 +788,15 @@ static int ocfs2_parse_options(struct super_block *sb,
 			else
 				osb->s_atime_quantum = OCFS2_DEFAULT_ATIME_QUANTUM;
 			break;
+		case Opt_slot:
+			option = 0;
+			if (match_int(&args[0], &option)) {
+				status = 0;
+				goto bail;
+			}
+			if (option)
+				*slot = (s16)option;
+			break;
 		default:
 			mlog(ML_ERROR,
 			     "Unrecognized mount option \"%s\" "
diff --git a/fs/ocfs2/super.h b/fs/ocfs2/super.h
index 783f5270f2a..3b9cb3d0b00 100644
--- a/fs/ocfs2/super.h
+++ b/fs/ocfs2/super.h
@@ -45,4 +45,6 @@ void __ocfs2_abort(struct super_block *sb,
 
 #define ocfs2_abort(sb, fmt, args...) __ocfs2_abort(sb, __PRETTY_FUNCTION__, fmt, ##args)
 
+unsigned long long ocfs2_max_file_offset(unsigned int blockshift);
+
 #endif /* OCFS2_SUPER_H */