Added all files

4 files changed, 5824 insertions, 0 deletions

diff --git a/xlators/cluster/unify/src/Makefile.am b/xlators/cluster/unify/src/Makefile.am
new file mode 100644
index 00000000000..b9e6f63e9d7
--- /dev/null
+++ b/xlators/cluster/unify/src/Makefile.am
@@ -0,0 +1,16 @@
+
+xlator_LTLIBRARIES = unify.la
+xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/cluster
+
+unify_la_LDFLAGS = -module -avoidversion
+
+unify_la_SOURCES = unify.c unify-self-heal.c
+unify_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+
+noinst_HEADERS = unify.h
+
+AM_CFLAGS = -fPIC -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -Wall -D$(GF_HOST_OS) \
+	-I$(top_srcdir)/libglusterfs/src -shared -nostartfiles $(GF_CFLAGS)
+
+CLEANFILES = 
+
diff --git a/xlators/cluster/unify/src/unify-self-heal.c b/xlators/cluster/unify/src/unify-self-heal.c
new file mode 100644
index 00000000000..4885dd91a35
--- /dev/null
+++ b/xlators/cluster/unify/src/unify-self-heal.c
@@ -0,0 +1,1225 @@
+/*
+  Copyright (c) 2007, 2008 Z RESEARCH, Inc. <http://www.zresearch.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * unify-self-heal.c : 
+ *   This file implements few functions which enables 'unify' translator 
+ *  to be consistent in its behaviour when 
+ *     > a node fails, 
+ *     > a node gets added, 
+ *     > a failed node comes back
+ *     > a new namespace server is added (ie, an fresh namespace server).
+ * 
+ *  This functionality of 'unify' will enable glusterfs to support storage
+ *  system failure, and maintain consistancy. This works both ways, ie, when
+ *  an entry (either file or directory) is found on namespace server, and not
+ *  on storage nodes, its created in storage nodes and vica-versa.
+ * 
+ *  The two fops, where it can be implemented are 'getdents ()' and 'lookup ()'
+ *
+ */
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glusterfs.h"
+#include "unify.h"
+#include "dict.h"
+#include "xlator.h"
+#include "hashfn.h"
+#include "logging.h"
+#include "stack.h"
+#include "common-utils.h"
+
+int32_t
+unify_sh_getdents_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno,
+		       dir_entry_t *entry,
+		       int32_t count);
+
+int32_t
+unify_sh_ns_getdents_cbk (call_frame_t *frame,
+			  void *cookie,
+			  xlator_t *this,
+			  int32_t op_ret,
+			  int32_t op_errno,
+			  dir_entry_t *entry,
+			  int32_t count);
+
+int32_t
+unify_bgsh_getdents_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno,
+			 dir_entry_t *entry,
+			 int32_t count);
+
+int32_t
+unify_bgsh_ns_getdents_cbk (call_frame_t *frame,
+			    void *cookie,
+			    xlator_t *this,
+			    int32_t op_ret,
+			    int32_t op_errno,
+			    dir_entry_t *entry,
+			    int32_t count);
+
+/**
+ * unify_local_wipe - free all the extra allocation of local->* here.
+ */
+static void 
+unify_local_wipe (unify_local_t *local)
+{
+	/* Free the strdup'd variables in the local structure */
+	if (local->name) {
+		FREE (local->name);
+	}
+
+	if (local->sh_struct) {
+		if (local->sh_struct->offset_list)
+			FREE (local->sh_struct->offset_list);
+
+		if (local->sh_struct->entry_list)
+			FREE (local->sh_struct->entry_list);
+
+		if (local->sh_struct->count_list)
+			FREE (local->sh_struct->count_list);
+
+		FREE (local->sh_struct);
+	}
+
+	loc_wipe (&local->loc1);
+	loc_wipe (&local->loc2);
+}
+
+int32_t 
+unify_sh_setdents_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno)
+{
+	int32_t callcnt = -1;
+	unify_local_t *local = frame->local;
+	inode_t *inode = NULL;
+	dict_t *tmp_dict = NULL;
+	dir_entry_t *prev, *entry, *trav;
+
+	LOCK (&frame->lock);
+	{
+		/* if local->call_count == 0, that means, setdents on 
+		 * storagenodes is still pending.
+		 */
+		if (local->call_count)
+			callcnt = --local->call_count;
+	}
+	UNLOCK (&frame->lock);
+
+	if (callcnt == 0) {
+		if (local->sh_struct->entry_list[0]) {
+			prev = entry = local->sh_struct->entry_list[0];
+			if (!entry)
+				return 0;
+			trav = entry->next;
+			while (trav) {
+				prev->next = trav->next;
+				FREE (trav->name);
+				if (S_ISLNK (trav->buf.st_mode))
+					FREE (trav->link);
+				FREE (trav);
+				trav = prev->next;
+			}
+			FREE (entry);
+		}
+
+		if (!local->flags) {
+			if (local->sh_struct->count_list[0] >= 
+			    UNIFY_SELF_HEAL_GETDENTS_COUNT) {
+				/* count == size, that means, there are more entries
+				   to read from */
+				//local->call_count = 0;
+				local->sh_struct->offset_list[0] += 
+					UNIFY_SELF_HEAL_GETDENTS_COUNT;
+				STACK_WIND (frame,
+					    unify_sh_ns_getdents_cbk,
+					    NS(this),
+					    NS(this)->fops->getdents,
+					    local->fd,
+					    UNIFY_SELF_HEAL_GETDENTS_COUNT,
+					    local->sh_struct->offset_list[0],
+					    GF_GET_DIR_ONLY);
+			}		
+		} else {
+			inode = local->loc1.inode;
+			fd_unref (local->fd);
+			tmp_dict = local->dict;
+
+			unify_local_wipe (local);
+			
+			STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+				      inode, &local->stbuf, local->dict);
+			if (tmp_dict)
+				dict_unref (local->dict);
+		}
+	}
+  
+	return 0;
+}
+
+
+int32_t
+unify_sh_ns_getdents_cbk (call_frame_t *frame,
+			  void *cookie,
+			  xlator_t *this,
+			  int32_t op_ret,
+			  int32_t op_errno,
+			  dir_entry_t *entry,
+			  int32_t count)
+{
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	long index = 0;
+	unsigned long final = 0;
+	dir_entry_t *tmp = CALLOC (1, sizeof (dir_entry_t));
+	
+	local->sh_struct->entry_list[0] = tmp;
+	local->sh_struct->count_list[0] = count;
+	if (entry) {
+		tmp->next = entry->next;
+		entry->next = NULL;
+	}
+
+	if ((count < UNIFY_SELF_HEAL_GETDENTS_COUNT) || !entry) {
+		final = 1;
+	}
+
+	LOCK (&frame->lock);
+	{
+		/* local->call_count will be '0' till now. make it 1 so, it 
+		   can be UNWIND'ed for the last call. */
+		local->call_count = priv->child_count;
+		if (final)
+			local->flags = 1;
+	}
+	UNLOCK (&frame->lock);
+
+	for (index = 0; index < priv->child_count; index++) 
+	{
+		STACK_WIND_COOKIE (frame,
+				   unify_sh_setdents_cbk, 
+				   (void *)index,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->setdents,
+				   local->fd, GF_SET_DIR_ONLY,
+				   local->sh_struct->entry_list[0], count);
+	}
+
+	return 0;
+}
+
+int32_t 
+unify_sh_ns_setdents_cbk (call_frame_t *frame,
+			  void *cookie,
+			  xlator_t *this,
+			  int32_t op_ret,
+			  int32_t op_errno)
+{
+	int32_t callcnt = -1;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	long index = (long)cookie;
+	dir_entry_t *prev, *entry, *trav;
+
+	LOCK (&frame->lock);
+	{
+		if (local->sh_struct->entry_list[index]) {
+			prev = entry = local->sh_struct->entry_list[index];
+			trav = entry->next;
+			while (trav) {
+				prev->next = trav->next;
+				FREE (trav->name);
+				if (S_ISLNK (trav->buf.st_mode))
+					FREE (trav->link);
+				FREE (trav);
+				trav = prev->next;
+			}
+			FREE (entry);
+		}
+	}
+	UNLOCK (&frame->lock);
+
+	if (local->sh_struct->count_list[index] < 
+	    UNIFY_SELF_HEAL_GETDENTS_COUNT) {
+		LOCK (&frame->lock);
+		{
+			callcnt = --local->call_count;
+		}
+		UNLOCK (&frame->lock);
+	} else {
+		/* count == size, that means, there are more entries 
+		   to read from */
+		local->sh_struct->offset_list[index] += 
+			UNIFY_SELF_HEAL_GETDENTS_COUNT;
+		STACK_WIND_COOKIE (frame,
+				   unify_sh_getdents_cbk,
+				   cookie,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->getdents,
+				   local->fd,
+				   UNIFY_SELF_HEAL_GETDENTS_COUNT,
+				   local->sh_struct->offset_list[index],
+				   GF_GET_ALL);
+    
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"readdir on (%s) with offset %"PRId64"", 
+			priv->xl_array[index]->name, 
+			local->sh_struct->offset_list[index]);
+	}
+
+	if (!callcnt) {
+		/* All storage nodes have done unified setdents on NS node.
+		 * Now, do getdents from NS and do setdents on storage nodes.
+		 */
+    
+		/* sh_struct->offset_list is no longer required for
+		   storage nodes now */
+		local->sh_struct->offset_list[0] = 0; /* reset */
+
+		STACK_WIND (frame,
+			    unify_sh_ns_getdents_cbk,
+			    NS(this),
+			    NS(this)->fops->getdents,
+			    local->fd,
+			    UNIFY_SELF_HEAL_GETDENTS_COUNT,
+			    0, /* In this call, do send '0' as offset */
+			    GF_GET_DIR_ONLY);
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_sh_getdents_cbk -
+ */
+int32_t
+unify_sh_getdents_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno,
+		       dir_entry_t *entry,
+		       int32_t count)
+{
+	int32_t callcnt = -1;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	long index = (long)cookie;
+	dir_entry_t *tmp = NULL; 
+
+	if (op_ret >= 0 && count > 0) {
+		/* There is some dentry found, just send the dentry to NS */
+		tmp = CALLOC (1, sizeof (dir_entry_t));
+		local->sh_struct->entry_list[index] = tmp;
+		local->sh_struct->count_list[index] = count;
+		if (entry) {
+			tmp->next = entry->next;
+			entry->next = NULL;
+		}
+		STACK_WIND_COOKIE (frame,
+				   unify_sh_ns_setdents_cbk,
+				   cookie,
+				   NS(this),
+				   NS(this)->fops->setdents,
+				   local->fd,
+				   GF_SET_IF_NOT_PRESENT,
+				   local->sh_struct->entry_list[index],
+				   count);
+		return 0;
+	}
+  
+	if (count < UNIFY_SELF_HEAL_GETDENTS_COUNT) {
+		LOCK (&frame->lock);
+		{
+			callcnt = --local->call_count;
+		}
+		UNLOCK (&frame->lock);
+	} else {
+		/* count == size, that means, there are more entries 
+		   to read from */
+		local->sh_struct->offset_list[index] += 
+			UNIFY_SELF_HEAL_GETDENTS_COUNT;
+		STACK_WIND_COOKIE (frame,
+				   unify_sh_getdents_cbk,
+				   cookie,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->getdents,
+				   local->fd,
+				   UNIFY_SELF_HEAL_GETDENTS_COUNT,
+				   local->sh_struct->offset_list[index],
+				   GF_GET_ALL);
+    
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"readdir on (%s) with offset %"PRId64"", 
+			priv->xl_array[index]->name, 
+			local->sh_struct->offset_list[index]);
+	}
+
+	if (!callcnt) {
+		/* All storage nodes have done unified setdents on NS node.
+		 * Now, do getdents from NS and do setdents on storage nodes.
+		 */
+    
+		/* sh_struct->offset_list is no longer required for
+		   storage nodes now */
+		local->sh_struct->offset_list[0] = 0; /* reset */
+
+		STACK_WIND (frame,
+			    unify_sh_ns_getdents_cbk,
+			    NS(this),
+			    NS(this)->fops->getdents,
+			    local->fd,
+			    UNIFY_SELF_HEAL_GETDENTS_COUNT,
+			    0, /* In this call, do send '0' as offset */
+			    GF_GET_DIR_ONLY);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_sh_opendir_cbk -
+ *
+ * @cookie: 
+ */
+int32_t 
+unify_sh_opendir_cbk (call_frame_t *frame,
+		      void *cookie,
+		      xlator_t *this,
+		      int32_t op_ret,
+		      int32_t op_errno,
+		      fd_t *fd)
+{
+	int32_t callcnt = 0;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int16_t index = 0;
+	inode_t *inode = NULL;
+	dict_t *tmp_dict = NULL;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+    
+		if (op_ret >= 0) {
+			local->op_ret = op_ret;
+		} else {
+			gf_log (this->name, GF_LOG_WARNING, "failed");
+			local->failed = 1;
+		}
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		local->call_count = priv->child_count + 1;
+    
+		if (!local->failed) {
+			/* send getdents() namespace after finishing
+			   storage nodes */
+			local->call_count--; 
+      
+			fd_bind (fd);
+
+			if (local->call_count) {
+				/* Used as the offset index. This list keeps
+				 * track of offset sent to each node during
+				 * STACK_WIND.
+				 */
+				local->sh_struct->offset_list = 
+					calloc (priv->child_count, 
+						sizeof (off_t));
+				ERR_ABORT (local->sh_struct->offset_list);
+	
+				local->sh_struct->entry_list = 
+					calloc (priv->child_count, 
+						sizeof (dir_entry_t *));
+				ERR_ABORT (local->sh_struct->entry_list);
+
+				local->sh_struct->count_list = 
+					calloc (priv->child_count, 
+						sizeof (int));
+				ERR_ABORT (local->sh_struct->count_list);
+
+				/* Send getdents on all the fds */
+				for (index = 0; 
+				     index < priv->child_count; index++) {
+					STACK_WIND_COOKIE (frame,
+							   unify_sh_getdents_cbk,
+							   (void *)(long)index,
+							   priv->xl_array[index],
+							   priv->xl_array[index]->fops->getdents,
+							   local->fd,
+							   UNIFY_SELF_HEAL_GETDENTS_COUNT,
+							   0, /* In this call, do send '0' as offset */
+							   GF_GET_ALL);
+				}
+
+				/* did stack wind, so no need to unwind here */
+				return 0;
+			} /* (local->call_count) */
+		} /* (!local->failed) */
+
+		/* Opendir failed on one node. */ 
+		inode = local->loc1.inode;
+		fd_unref (local->fd);
+		tmp_dict = local->dict;
+
+		unify_local_wipe (local);
+		/* Only 'self-heal' failed, lookup() was successful. */
+		local->op_ret = 0;
+
+		/* This is lookup_cbk ()'s UNWIND. */
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, inode,
+			      &local->stbuf, local->dict);
+		if (tmp_dict)
+			dict_unref (tmp_dict);
+	}
+
+	return 0;
+}
+
+/**
+ * gf_sh_checksum_cbk - 
+ * 
+ * @frame: frame used in lookup. get a copy of it, and use that copy.
+ * @this: pointer to unify xlator.
+ * @inode: pointer to inode, for which the consistency check is required.
+ *
+ */
+int32_t 
+unify_sh_checksum_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno,
+		       uint8_t *file_checksum,
+		       uint8_t *dir_checksum)
+{
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int16_t index = 0;
+	int32_t callcnt = 0;
+	inode_t *inode = NULL;
+	dict_t *tmp_dict = NULL;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if (op_ret >= 0) {
+			if (NS(this) == (xlator_t *)cookie) {
+				memcpy (local->sh_struct->ns_file_checksum, 
+					file_checksum, ZR_FILENAME_MAX);
+				memcpy (local->sh_struct->ns_dir_checksum, 
+					dir_checksum, ZR_FILENAME_MAX);
+			} else {
+				if (local->entry_count == 0) {
+					/* Initialize the dir_checksum to be 
+					 * used for comparision with other
+					 * storage nodes. Should be done for
+					 * the first successful call *only*. 
+					 */
+                                        /* Using 'entry_count' as a flag */
+					local->entry_count = 1;
+					memcpy (local->sh_struct->dir_checksum,
+						dir_checksum, ZR_FILENAME_MAX);
+				}
+
+				/* Reply from the storage nodes */
+				for (index = 0; 
+				     index < ZR_FILENAME_MAX; index++) {
+					/* Files should be present in
+					   only one node */
+					local->sh_struct->file_checksum[index] ^= file_checksum[index];
+	  
+					/* directory structure should be
+					   same accross */
+					if (local->sh_struct->dir_checksum[index] != dir_checksum[index])
+						local->failed = 1;
+				}
+			}
+		} 
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		for (index = 0; index < ZR_FILENAME_MAX ; index++) {
+			if (local->sh_struct->file_checksum[index] != 
+			    local->sh_struct->ns_file_checksum[index]) {
+				local->failed = 1;
+				break;
+			}
+			if (local->sh_struct->dir_checksum[index] != 
+			    local->sh_struct->ns_dir_checksum[index]) {
+				local->failed = 1;
+				break;
+			}
+		}
+	
+		if (local->failed) {
+			/* Log it, it should be a rare event */
+			gf_log (this->name, GF_LOG_WARNING, 
+				"Self-heal triggered on directory %s", 
+				local->loc1.path);
+
+			/* Any self heal will be done at directory level */
+			local->call_count = 0;
+			local->op_ret = -1;
+			local->failed = 0;
+      
+			local->fd = fd_create (local->loc1.inode, 
+					       frame->root->pid);
+
+			local->call_count = priv->child_count + 1;
+	
+			for (index = 0; 
+			     index < (priv->child_count + 1); index++) {
+				STACK_WIND_COOKIE (frame,
+						   unify_sh_opendir_cbk,
+						   priv->xl_array[index]->name,
+						   priv->xl_array[index],
+						   priv->xl_array[index]->fops->opendir,
+						   &local->loc1,
+						   local->fd);
+			}
+			/* opendir can be done on the directory */
+			return 0;
+		}
+
+		/* no mismatch */
+		inode = local->loc1.inode;
+		tmp_dict = local->dict;
+
+		unify_local_wipe (local);
+
+		/* This is lookup_cbk ()'s UNWIND. */
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      inode,
+			      &local->stbuf,
+			      local->dict);
+		if (tmp_dict)
+			dict_unref (tmp_dict);
+	}
+
+	return 0;
+}
+
+/* Foreground self-heal part over */
+
+/* Background self-heal part */
+
+int32_t 
+unify_bgsh_setdents_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno)
+{
+	int32_t callcnt = -1;
+	unify_local_t *local = frame->local;
+	dir_entry_t *prev, *entry, *trav;
+
+	LOCK (&frame->lock);
+	{
+		/* if local->call_count == 0, that means, setdents 
+		   on storagenodes is still pending. */
+		if (local->call_count)
+			callcnt = --local->call_count;
+	}
+	UNLOCK (&frame->lock);
+
+
+	if (callcnt == 0) {
+		if (local->sh_struct->entry_list[0]) {
+			prev = entry = local->sh_struct->entry_list[0];
+			trav = entry->next;
+			while (trav) {
+				prev->next = trav->next;
+				FREE (trav->name);
+				if (S_ISLNK (trav->buf.st_mode))
+					FREE (trav->link);
+				FREE (trav);
+				trav = prev->next;
+			}
+			FREE (entry);
+		}
+
+		if (!local->flags) {
+			if (local->sh_struct->count_list[0] >= 
+			    UNIFY_SELF_HEAL_GETDENTS_COUNT) {
+				/* count == size, that means, there are more
+				   entries to read from */
+				//local->call_count = 0;
+				local->sh_struct->offset_list[0] += 
+					UNIFY_SELF_HEAL_GETDENTS_COUNT;
+				STACK_WIND (frame,
+					    unify_bgsh_ns_getdents_cbk,
+					    NS(this),
+					    NS(this)->fops->getdents,
+					    local->fd,
+					    UNIFY_SELF_HEAL_GETDENTS_COUNT,
+					    local->sh_struct->offset_list[0],
+					    GF_GET_DIR_ONLY);
+			}		
+		} else {
+			fd_unref (local->fd);
+			unify_local_wipe (local);
+			STACK_DESTROY (frame->root);
+		}
+	}
+
+	return 0;
+}
+
+
+int32_t
+unify_bgsh_ns_getdents_cbk (call_frame_t *frame,
+			    void *cookie,
+			    xlator_t *this,
+			    int32_t op_ret,
+			    int32_t op_errno,
+			    dir_entry_t *entry,
+			    int32_t count)
+{
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	long index = 0;
+	unsigned long final = 0;
+	dir_entry_t *tmp = CALLOC (1, sizeof (dir_entry_t));
+
+	local->sh_struct->entry_list[0] = tmp;
+	local->sh_struct->count_list[0] = count;
+	if (entry) {
+		tmp->next = entry->next;
+		entry->next = NULL;
+	}
+
+	if ((count < UNIFY_SELF_HEAL_GETDENTS_COUNT) || !entry) {
+		final = 1;
+	}
+
+	LOCK (&frame->lock);
+	{
+		/* local->call_count will be '0' till now. make it 1 so, 
+		   it can be UNWIND'ed for the last call. */
+		local->call_count = priv->child_count;
+		if (final)
+			local->flags = 1;
+	}
+	UNLOCK (&frame->lock);
+
+	for (index = 0; index < priv->child_count; index++) 
+	{
+		STACK_WIND_COOKIE (frame,
+				   unify_bgsh_setdents_cbk, 
+				   (void *)index,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->setdents,
+				   local->fd, GF_SET_DIR_ONLY,
+				   local->sh_struct->entry_list[0], count);
+	}
+
+	return 0;
+}
+
+int32_t 
+unify_bgsh_ns_setdents_cbk (call_frame_t *frame,
+			    void *cookie,
+			    xlator_t *this,
+			    int32_t op_ret,
+			    int32_t op_errno)
+{
+	int32_t callcnt = -1;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	long index = (long)cookie;
+	dir_entry_t *prev, *entry, *trav;
+
+	if (local->sh_struct->entry_list[index]) {
+		prev = entry = local->sh_struct->entry_list[index];
+		if (!entry)
+			return 0;
+		trav = entry->next;
+		while (trav) {
+			prev->next = trav->next;
+			FREE (trav->name);
+			if (S_ISLNK (trav->buf.st_mode))
+				FREE (trav->link);
+			FREE (trav);
+			trav = prev->next;
+		}
+		FREE (entry);
+	}
+
+	if (local->sh_struct->count_list[index] < 
+	    UNIFY_SELF_HEAL_GETDENTS_COUNT) {
+		LOCK (&frame->lock);
+		{
+			callcnt = --local->call_count;
+		}
+		UNLOCK (&frame->lock);
+	} else {
+		/* count == size, that means, there are more entries 
+		   to read from */
+		local->sh_struct->offset_list[index] += 
+			UNIFY_SELF_HEAL_GETDENTS_COUNT;
+		STACK_WIND_COOKIE (frame,
+				   unify_bgsh_getdents_cbk,
+				   cookie,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->getdents,
+				   local->fd,
+				   UNIFY_SELF_HEAL_GETDENTS_COUNT,
+				   local->sh_struct->offset_list[index],
+				   GF_GET_ALL);
+    
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"readdir on (%s) with offset %"PRId64"", 
+			priv->xl_array[index]->name, 
+			local->sh_struct->offset_list[index]);
+	}
+
+	if (!callcnt) {
+		/* All storage nodes have done unified setdents on NS node.
+		 * Now, do getdents from NS and do setdents on storage nodes.
+		 */
+    
+		/* sh_struct->offset_list is no longer required for
+		   storage nodes now */
+		local->sh_struct->offset_list[0] = 0; /* reset */
+
+		STACK_WIND (frame,
+			    unify_bgsh_ns_getdents_cbk,
+			    NS(this),
+			    NS(this)->fops->getdents,
+			    local->fd,
+			    UNIFY_SELF_HEAL_GETDENTS_COUNT,
+			    0, /* In this call, do send '0' as offset */
+			    GF_GET_DIR_ONLY);
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_bgsh_getdents_cbk -
+ */
+int32_t
+unify_bgsh_getdents_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno,
+			 dir_entry_t *entry,
+			 int32_t count)
+{
+	int32_t callcnt = -1;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	long index = (long)cookie;
+	dir_entry_t *tmp = NULL; 
+
+	if (op_ret >= 0 && count > 0) {
+		/* There is some dentry found, just send the dentry to NS */
+		tmp = CALLOC (1, sizeof (dir_entry_t));
+		local->sh_struct->entry_list[index] = tmp;
+		local->sh_struct->count_list[index] = count;
+		if (entry) {
+			tmp->next = entry->next;
+			entry->next = NULL;
+		}
+		STACK_WIND_COOKIE (frame,
+				   unify_bgsh_ns_setdents_cbk,
+				   cookie,
+				   NS(this),
+				   NS(this)->fops->setdents,
+				   local->fd,
+				   GF_SET_IF_NOT_PRESENT,
+				   local->sh_struct->entry_list[index],
+				   count);
+		return 0;
+	}
+  
+	if (count < UNIFY_SELF_HEAL_GETDENTS_COUNT) {
+		LOCK (&frame->lock);
+		{
+			callcnt = --local->call_count;
+		}
+		UNLOCK (&frame->lock);
+	} else {
+		/* count == size, that means, there are more entries to read from */
+		local->sh_struct->offset_list[index] += 
+			UNIFY_SELF_HEAL_GETDENTS_COUNT;
+
+		STACK_WIND_COOKIE (frame,
+				   unify_bgsh_getdents_cbk,
+				   cookie,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->getdents,
+				   local->fd,
+				   UNIFY_SELF_HEAL_GETDENTS_COUNT,
+				   local->sh_struct->offset_list[index],
+				   GF_GET_ALL);
+    
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"readdir on (%s) with offset %"PRId64"", 
+			priv->xl_array[index]->name, 
+			local->sh_struct->offset_list[index]);
+	}
+
+	if (!callcnt) {
+		/* All storage nodes have done unified setdents on NS node.
+		 * Now, do getdents from NS and do setdents on storage nodes.
+		 */
+    
+		/* sh_struct->offset_list is no longer required for 
+		   storage nodes now */
+		local->sh_struct->offset_list[0] = 0; /* reset */
+
+		STACK_WIND (frame,
+			    unify_bgsh_ns_getdents_cbk,
+			    NS(this),
+			    NS(this)->fops->getdents,
+			    local->fd,
+			    UNIFY_SELF_HEAL_GETDENTS_COUNT,
+			    0, /* In this call, do send '0' as offset */
+			    GF_GET_DIR_ONLY);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_bgsh_opendir_cbk -
+ *
+ * @cookie: 
+ */
+int32_t 
+unify_bgsh_opendir_cbk (call_frame_t *frame,
+			void *cookie,
+			xlator_t *this,
+			int32_t op_ret,
+			int32_t op_errno,
+			fd_t *fd)
+{
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int32_t callcnt = 0;
+	int16_t index = 0;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+    
+		if (op_ret >= 0) {
+			local->op_ret = op_ret;
+		} else {
+			local->failed = 1;
+		}
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		local->call_count = priv->child_count + 1;
+    
+		if (!local->failed) {
+			/* send getdents() namespace after finishing 
+			   storage nodes */
+			local->call_count--; 
+			callcnt = local->call_count;
+      
+			fd_bind (fd);
+
+			if (local->call_count) {
+				/* Used as the offset index. This list keeps 
+				   track of offset sent to each node during 
+				   STACK_WIND. */
+				local->sh_struct->offset_list = 
+					calloc (priv->child_count, 
+						sizeof (off_t));
+				ERR_ABORT (local->sh_struct->offset_list);
+	
+				local->sh_struct->entry_list = 
+					calloc (priv->child_count, 
+						sizeof (dir_entry_t *));
+				ERR_ABORT (local->sh_struct->entry_list);
+
+				local->sh_struct->count_list = 
+					calloc (priv->child_count, 
+						sizeof (int));
+				ERR_ABORT (local->sh_struct->count_list);
+
+				/* Send getdents on all the fds */
+				for (index = 0; 
+				     index < priv->child_count; index++) {
+					STACK_WIND_COOKIE (frame,
+							   unify_bgsh_getdents_cbk,
+							   (void *)(long)index,
+							   priv->xl_array[index],
+							   priv->xl_array[index]->fops->getdents,
+							   local->fd,
+							   UNIFY_SELF_HEAL_GETDENTS_COUNT,
+							   0, /* In this call, do send '0' as offset */
+							   GF_GET_ALL);
+				}
+				/* did a stack wind, so no need to unwind here */
+				return 0;
+			} /* (local->call_count) */
+		} /* (!local->failed) */
+
+		/* Opendir failed on one node. 	 */
+		fd_unref (local->fd);
+		
+		unify_local_wipe (local);
+		STACK_DESTROY (frame->root);
+	}
+
+	return 0;
+}
+
+/**
+ * gf_bgsh_checksum_cbk - 
+ * 
+ * @frame: frame used in lookup. get a copy of it, and use that copy.
+ * @this: pointer to unify xlator.
+ * @inode: pointer to inode, for which the consistency check is required.
+ *
+ */
+int32_t 
+unify_bgsh_checksum_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno,
+			 uint8_t *file_checksum,
+			 uint8_t *dir_checksum)
+{
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int16_t index = 0;
+	int32_t callcnt = 0;
+  
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if (op_ret >= 0) {
+			if (NS(this) == (xlator_t *)cookie) {
+				memcpy (local->sh_struct->ns_file_checksum, 
+					file_checksum, ZR_FILENAME_MAX);
+				memcpy (local->sh_struct->ns_dir_checksum, 
+					dir_checksum, ZR_FILENAME_MAX);
+			} else {
+				if (local->entry_count == 0) {
+					/* Initialize the dir_checksum to be 
+					 * used for comparision with other 
+					 * storage nodes. Should be done for
+					 * the first successful call *only*. 
+					 */
+					/* Using 'entry_count' as a flag */
+					local->entry_count = 1; 
+					memcpy (local->sh_struct->dir_checksum,
+						dir_checksum, ZR_FILENAME_MAX);
+				}
+
+				/* Reply from the storage nodes */
+				for (index = 0; 
+				     index < ZR_FILENAME_MAX; index++) {
+					/* Files should be present in only 
+					   one node */
+					local->sh_struct->file_checksum[index] ^= file_checksum[index];
+	  
+					/* directory structure should be same 
+					   accross */
+					if (local->sh_struct->dir_checksum[index] != dir_checksum[index])
+						local->failed = 1;
+				}
+			}
+		} 
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		for (index = 0; index < ZR_FILENAME_MAX ; index++) {
+			if (local->sh_struct->file_checksum[index] != 
+			    local->sh_struct->ns_file_checksum[index]) {
+				local->failed = 1;
+				break;
+			}
+			if (local->sh_struct->dir_checksum[index] != 
+			    local->sh_struct->ns_dir_checksum[index]) {
+				local->failed = 1;
+				break;
+			}
+		}
+	
+		if (local->failed) {
+			/* Log it, it should be a rare event */
+			gf_log (this->name, GF_LOG_WARNING, 
+				"Self-heal triggered on directory %s", 
+				local->loc1.path);
+
+			/* Any self heal will be done at the directory level */
+			local->op_ret = -1;
+			local->failed = 0;
+      
+			local->fd = fd_create (local->loc1.inode, 
+					       frame->root->pid);
+			local->call_count = priv->child_count + 1;
+	
+			for (index = 0; 
+			     index < (priv->child_count + 1); index++) {
+				STACK_WIND_COOKIE (frame,
+						   unify_bgsh_opendir_cbk,
+						   priv->xl_array[index]->name,
+						   priv->xl_array[index],
+						   priv->xl_array[index]->fops->opendir,
+						   &local->loc1,
+						   local->fd);
+			}
+      
+			/* opendir can be done on the directory */
+			return 0;
+		}
+
+		/* no mismatch */
+		unify_local_wipe (local);
+		STACK_DESTROY (frame->root);
+	}
+
+	return 0;
+}
+
+/* Background self-heal part over */
+
+
+
+
+/**
+ * zr_unify_self_heal - 
+ * 
+ * @frame: frame used in lookup. get a copy of it, and use that copy.
+ * @this: pointer to unify xlator.
+ * @inode: pointer to inode, for which the consistency check is required.
+ *
+ */
+int32_t 
+zr_unify_self_heal (call_frame_t *frame,
+		    xlator_t *this,
+		    unify_local_t *local)
+{
+	unify_private_t *priv = this->private;
+	call_frame_t *bg_frame = NULL;
+	unify_local_t *bg_local = NULL;
+	inode_t *tmp_inode = NULL;
+	dict_t *tmp_dict = NULL;
+	int16_t index = 0;
+  
+	if (local->inode_generation < priv->inode_generation) {
+		/* Any self heal will be done at the directory level */
+		/* Update the inode's generation to the current generation
+		   value. */
+		local->inode_generation = priv->inode_generation;
+		inode_ctx_put (local->loc1.inode, this, 
+			  (uint64_t)(long)local->inode_generation);
+
+		if (priv->self_heal == ZR_UNIFY_FG_SELF_HEAL) {
+			local->op_ret = 0;
+			local->failed = 0;
+			local->call_count = priv->child_count + 1;
+			local->sh_struct = 
+				calloc (1, sizeof (struct unify_self_heal_struct));
+      
+			/* +1 is for NS */
+			for (index = 0; 
+			     index < (priv->child_count + 1); index++) {
+				STACK_WIND_COOKIE (frame,
+						   unify_sh_checksum_cbk,
+						   priv->xl_array[index],
+						   priv->xl_array[index],
+						   priv->xl_array[index]->fops->checksum,
+						   &local->loc1,
+						   0);
+			}
+
+			/* Self-heal in foreground, hence no need 
+			   to UNWIND here */
+			return 0;
+		}
+
+		/* Self Heal done in background */
+		bg_frame = copy_frame (frame);
+		INIT_LOCAL (bg_frame, bg_local);
+		loc_copy (&bg_local->loc1, &local->loc1);
+		bg_local->op_ret = 0;
+		bg_local->failed = 0;
+		bg_local->call_count = priv->child_count + 1;
+		bg_local->sh_struct = 
+			calloc (1, sizeof (struct unify_self_heal_struct));
+    
+		/* +1 is for NS */
+		for (index = 0; index < (priv->child_count + 1); index++) {
+			STACK_WIND_COOKIE (bg_frame,
+					   unify_bgsh_checksum_cbk,
+					   priv->xl_array[index],
+					   priv->xl_array[index],
+					   priv->xl_array[index]->fops->checksum,
+					   &bg_local->loc1,
+					   0);
+		}
+	}
+
+	/* generation number matches, self heal already done or
+	 * self heal done in background: just do STACK_UNWIND 
+	 */
+	tmp_inode = local->loc1.inode;
+	tmp_dict = local->dict;
+
+	unify_local_wipe (local);
+
+	/* This is lookup_cbk ()'s UNWIND. */
+	STACK_UNWIND (frame,
+		      local->op_ret,
+		      local->op_errno,
+		      tmp_inode,
+		      &local->stbuf,
+		      local->dict);
+
+	if (tmp_dict)
+		dict_unref (tmp_dict);
+
+	return 0;
+}
+
diff --git a/xlators/cluster/unify/src/unify.c b/xlators/cluster/unify/src/unify.c
new file mode 100644
index 00000000000..e2a5e14b191
--- /dev/null
+++ b/xlators/cluster/unify/src/unify.c
@@ -0,0 +1,4451 @@
+/*
+  Copyright (c) 2006, 2007, 2008, 2009 Z RESEARCH, Inc. <http://www.zresearch.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * xlators/cluster/unify:
+ *     - This xlator is one of the main translator in GlusterFS, which
+ *   actually does the clustering work of the file system. One need to 
+ *   understand that, unify assumes file to be existing in only one of 
+ *   the child node, and directories to be present on all the nodes. 
+ *
+ * NOTE:
+ *   Now, unify has support for global namespace, which is used to keep a 
+ * global view of fs's namespace tree. The stat for directories are taken
+ * just from the namespace, where as for files, just 'st_ino' is taken from
+ * Namespace node, and other stat info is taken from the actual storage node.
+ * Also Namespace node helps to keep consistant inode for files across 
+ * glusterfs (re-)mounts.
+ */
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "glusterfs.h"
+#include "unify.h"
+#include "dict.h"
+#include "xlator.h"
+#include "hashfn.h"
+#include "logging.h"
+#include "stack.h"
+#include "defaults.h"
+#include "common-utils.h"
+#include <signal.h>
+#include <libgen.h>
+#include "compat-errno.h"
+#include "compat.h"
+
+#define UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR(_loc) do { \
+  if (!(_loc && _loc->inode)) {                            \
+    STACK_UNWIND (frame, -1, EINVAL, NULL, NULL, NULL);    \
+    return 0;                                              \
+  }                                                        \
+} while(0)
+
+
+#define UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR(_fd) do { \
+  if (!(_fd && !fd_ctx_get (_fd, this, NULL))) {       \
+    STACK_UNWIND (frame, -1, EBADFD, NULL, NULL);      \
+    return 0;                                          \
+  }                                                    \
+} while(0)
+
+#define UNIFY_CHECK_FD_AND_UNWIND_ON_ERR(_fd) do { \
+  if (!_fd) {                                      \
+    STACK_UNWIND (frame, -1, EBADFD, NULL, NULL);  \
+    return 0;                                      \
+  }                                                \
+} while(0)
+
+/**
+ * unify_local_wipe - free all the extra allocation of local->* here.
+ */
+static void 
+unify_local_wipe (unify_local_t *local)
+{
+	/* Free the strdup'd variables in the local structure */
+	if (local->name) {
+		FREE (local->name);
+	}
+	loc_wipe (&local->loc1);
+	loc_wipe (&local->loc2);
+}
+
+
+
+/*
+ * unify_normalize_stats -
+ */
+void
+unify_normalize_stats (struct statvfs *buf,
+		       unsigned long bsize,
+		       unsigned long frsize)
+{
+	double factor;
+
+	if (buf->f_bsize != bsize) {
+		factor = ((double) buf->f_bsize) / bsize;
+		buf->f_bsize  = bsize;
+		buf->f_bfree  = (fsblkcnt_t) (factor * buf->f_bfree);
+		buf->f_bavail = (fsblkcnt_t) (factor * buf->f_bavail);
+	}
+  
+	if (buf->f_frsize != frsize) {
+		factor = ((double) buf->f_frsize) / frsize;
+		buf->f_frsize = frsize;
+		buf->f_blocks = (fsblkcnt_t) (factor * buf->f_blocks);
+	}
+}
+
+
+xlator_t *
+unify_loc_subvol (loc_t *loc, xlator_t *this)
+{
+	unify_private_t *priv = NULL;
+	xlator_t        *subvol = NULL;
+	int16_t         *list = NULL;
+	long             index = 0;
+	xlator_t        *subvol_i = NULL;
+	int              ret = 0;
+	uint64_t         tmp_list = 0;
+
+	priv   = this->private;
+	subvol = NS (this);
+
+	if (!S_ISDIR (loc->inode->st_mode)) {
+		ret = inode_ctx_get (loc->inode, this, &tmp_list);
+		list = (int16_t *)(long)tmp_list;
+		if (!list)
+			goto out;
+
+		for (index = 0; list[index] != -1; index++) {
+			subvol_i = priv->xl_array[list[index]];
+			if (subvol_i != NS (this)) {
+				subvol = subvol_i;
+				break;
+			}
+		}
+	}
+out:
+	return subvol;
+}
+
+
+
+/**
+ * unify_statfs_cbk -
+ */
+int32_t
+unify_statfs_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno,
+		  struct statvfs *stbuf)
+{
+	int32_t callcnt = 0;
+	struct statvfs *dict_buf = NULL;
+	unsigned long bsize;
+	unsigned long frsize;
+	unify_local_t *local = (unify_local_t *)frame->local;
+	call_frame_t *prev_frame = cookie;
+
+	LOCK (&frame->lock);
+	{
+		if (op_ret >= 0) {
+			/* when a call is successfull, add it to local->dict */
+			dict_buf = &local->statvfs_buf;
+
+			if (dict_buf->f_bsize != 0) {
+				bsize  = max (dict_buf->f_bsize, 
+					      stbuf->f_bsize);
+
+				frsize = max (dict_buf->f_frsize, 
+					      stbuf->f_frsize);
+				unify_normalize_stats(dict_buf, bsize, frsize);
+				unify_normalize_stats(stbuf, bsize, frsize);
+			} else {
+				dict_buf->f_bsize   = stbuf->f_bsize;
+				dict_buf->f_frsize  = stbuf->f_frsize;
+			}
+      
+			dict_buf->f_blocks += stbuf->f_blocks;
+			dict_buf->f_bfree  += stbuf->f_bfree;
+			dict_buf->f_bavail += stbuf->f_bavail;
+			dict_buf->f_files  += stbuf->f_files;
+			dict_buf->f_ffree  += stbuf->f_ffree;
+			dict_buf->f_favail += stbuf->f_favail;
+			dict_buf->f_fsid    = stbuf->f_fsid;
+			dict_buf->f_flag    = stbuf->f_flag;
+			dict_buf->f_namemax = stbuf->f_namemax;
+			local->op_ret = op_ret;
+		} else {
+			/* fop on storage node has failed due to some error */
+			if (op_errno != ENOTCONN) {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"child(%s): %s", 
+					prev_frame->this->name, 
+					strerror (op_errno));
+			}
+			local->op_errno = op_errno;
+		}
+		callcnt = --local->call_count;
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      &local->statvfs_buf);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_statfs -
+ */
+int32_t
+unify_statfs (call_frame_t *frame,
+	      xlator_t *this,
+	      loc_t *loc)
+{
+	unify_local_t *local = NULL;
+	xlator_list_t *trav = this->children;
+
+	INIT_LOCAL (frame, local);
+	local->call_count = ((unify_private_t *)this->private)->child_count;
+
+	while(trav) {
+		STACK_WIND (frame,
+			    unify_statfs_cbk,
+			    trav->xlator,
+			    trav->xlator->fops->statfs,
+			    loc);
+		trav = trav->next;
+	}
+
+	return 0;
+}
+
+/**
+ * unify_buf_cbk - 
+ */
+int32_t
+unify_buf_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno,
+	       struct stat *buf)
+{
+	int32_t callcnt = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+    
+		if (op_ret == -1) {
+			gf_log (this->name, GF_LOG_ERROR,
+				"%s(): child(%s): path(%s): %s", 
+				gf_fop_list[frame->root->op],
+				prev_frame->this->name, 
+				(local->loc1.path)?local->loc1.path:"", 
+				strerror (op_errno));
+
+			local->op_errno = op_errno;
+			if ((op_errno == ENOENT) && priv->optimist) 
+				local->op_ret = 0;
+		}
+
+		if (op_ret >= 0) {
+			local->op_ret = 0;
+
+			if (NS (this) == prev_frame->this) {
+				local->st_ino = buf->st_ino;
+				/* If the entry is directory, get the stat
+				   from NS node */
+				if (S_ISDIR (buf->st_mode) || 
+				    !local->stbuf.st_blksize) {
+					local->stbuf = *buf;
+				}
+			}
+
+			if ((!S_ISDIR (buf->st_mode)) && 
+			    (NS (this) != prev_frame->this)) {
+				/* If file, take the stat info from Storage 
+				   node. */
+				local->stbuf = *buf;
+			}
+		}
+	}
+	UNLOCK (&frame->lock);
+    
+	if (!callcnt) {
+		/* If the inode number is not filled, operation should
+		   fail */
+		if (!local->st_ino)
+			local->op_ret = -1;
+
+		local->stbuf.st_ino = local->st_ino;
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      &local->stbuf);
+	}
+
+	return 0;
+}
+
+#define check_if_dht_linkfile(s) ((s->st_mode & ~S_IFMT) == S_ISVTX)
+
+/**
+ * unify_lookup_cbk - 
+ */
+int32_t 
+unify_lookup_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno,
+		  inode_t *inode,
+		  struct stat *buf,
+		  dict_t *dict)
+{
+	int32_t callcnt = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	inode_t *tmp_inode = NULL;
+	dict_t *local_dict = NULL;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+ 
+		if (op_ret == -1) {
+			if ((op_errno != ENOTCONN) && (op_errno != ENOENT)) {
+				gf_log (this->name, GF_LOG_ERROR,
+					"child(%s): path(%s): %s", 
+					priv->xl_array[(long)cookie]->name, 
+					local->loc1.path, strerror (op_errno));
+				local->op_errno = op_errno;
+				local->failed = 1;
+
+			} else if (local->revalidate && 
+				   !(priv->optimist && (op_errno == ENOENT))) {
+
+				gf_log (this->name, 
+					(op_errno == ENOTCONN) ? 
+					GF_LOG_DEBUG:GF_LOG_ERROR,
+					"child(%s): path(%s): %s", 
+					priv->xl_array[(long)cookie]->name, 
+					local->loc1.path, strerror (op_errno));
+				local->op_errno = op_errno;
+				local->failed = 1;
+			}
+		}
+
+		if (op_ret == 0) {
+			local->op_ret = 0; 
+			
+			if (check_if_dht_linkfile(buf)) {
+				gf_log (this->name, GF_LOG_CRITICAL,
+					"file %s may be DHT link file on %s, "
+					"make sure the backend is not shared "
+					"between unify and DHT", 
+					local->loc1.path, 
+					priv->xl_array[(long)cookie]->name);
+			}
+
+			if (local->stbuf.st_mode && local->stbuf.st_blksize) {
+				/* make sure we already have a stbuf
+				   stored in local->stbuf */
+				if (S_ISDIR (local->stbuf.st_mode) && 
+				    !S_ISDIR (buf->st_mode)) {
+					gf_log (this->name, GF_LOG_CRITICAL, 
+						"[CRITICAL] '%s' is directory "
+						"on namespace, non-directory "
+						"on node '%s', returning EIO",
+						local->loc1.path, 
+						priv->xl_array[(long)cookie]->name);
+					local->return_eio = 1;
+				}
+				if (!S_ISDIR (local->stbuf.st_mode) && 
+				    S_ISDIR (buf->st_mode)) {
+					gf_log (this->name, GF_LOG_CRITICAL, 
+						"[CRITICAL] '%s' is directory "
+						"on node '%s', non-directory "
+						"on namespace, returning EIO",
+						local->loc1.path, 
+						priv->xl_array[(long)cookie]->name);
+					local->return_eio = 1;
+				}
+			}
+	
+			if (!local->revalidate && !S_ISDIR (buf->st_mode)) {
+				/* This is the first time lookup on file*/
+				if (!local->list) {
+					/* list is not allocated, allocate 
+					   the max possible range */
+					local->list = CALLOC (1, 2 * (priv->child_count + 2));
+					if (!local->list) {
+						gf_log (this->name, 
+							GF_LOG_CRITICAL, 
+							"Not enough memory");
+						STACK_UNWIND (frame, -1, 
+							      ENOMEM, inode, 
+							      NULL, NULL);
+						return 0;
+					}
+				}
+				/* update the index of the list */
+				local->list [local->index++] = 
+					(int16_t)(long)cookie;
+			}
+      
+			if ((!local->dict) && dict &&
+			    (priv->xl_array[(long)cookie] != NS(this)))	{
+				local->dict = dict_ref (dict);
+			}
+
+			/* index of NS node is == total child count */
+			if (priv->child_count == (int16_t)(long)cookie) {
+				/* Take the inode number from namespace */
+				local->st_ino = buf->st_ino;
+				if (S_ISDIR (buf->st_mode) || 
+				    !(local->stbuf.st_blksize)) {
+					local->stbuf = *buf;
+				}
+			} else if (!S_ISDIR (buf->st_mode)) {
+				/* If file, then get the stat from 
+				   storage node */
+				local->stbuf = *buf;
+			}
+
+			if (local->st_nlink < buf->st_nlink) {
+				local->st_nlink = buf->st_nlink;
+			}
+		}
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		local_dict = local->dict;
+		if (local->return_eio) {
+			gf_log (this->name, GF_LOG_CRITICAL, 
+				"[CRITICAL] Unable to fix the path (%s) with "
+				"self-heal, try manual verification. "
+				"returning EIO.", local->loc1.path);
+			unify_local_wipe (local);
+			STACK_UNWIND (frame, -1, EIO, inode, NULL, NULL);
+			if (local_dict)	{
+				dict_unref (local_dict);
+			}
+			return 0;
+		}
+
+		if (!local->stbuf.st_blksize) {
+			/* Inode not present */
+			local->op_ret = -1;
+		} else {
+			if (!local->revalidate && 
+			    !S_ISDIR (local->stbuf.st_mode)) { 
+				/* If its a file, big array is useless, 
+				   allocate the smaller one */
+				int16_t *list = NULL;
+				list = CALLOC (1, 2 * (local->index + 1));
+				ERR_ABORT (list);
+				memcpy (list, local->list, 2 * local->index);
+				/* Make the end of the list as -1 */
+				FREE (local->list);
+				local->list = list;
+				local->list [local->index] = -1;
+				/* Update the inode's ctx with proper array */
+				/* TODO: log on failure */
+				inode_ctx_put (local->loc1.inode, this, 
+					       (uint64_t)(long)local->list);
+			}
+
+			if (S_ISDIR(local->loc1.inode->st_mode)) {
+				/* lookup is done for directory */
+				if (local->failed && priv->self_heal) {
+					/* Triggering self-heal */
+                                        /* means, self-heal required for this 
+					   inode */
+					local->inode_generation = 0; 
+					priv->inode_generation++;
+				}
+			} else {
+				local->stbuf.st_ino = local->st_ino;
+			}
+	  
+			local->stbuf.st_nlink = local->st_nlink;
+		}
+		if (local->op_ret == -1) {
+			if (!local->revalidate && local->list)
+				FREE (local->list);
+		}
+
+		if ((local->op_ret >= 0) && local->failed && 
+		    local->revalidate) {
+			/* Done revalidate, but it failed */
+			if (op_errno != ENOTCONN) {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"Revalidate failed for path(%s): %s", 
+					local->loc1.path, strerror (op_errno));
+			}
+			local->op_ret = -1;
+		}
+
+		if ((priv->self_heal && !priv->optimist) && 
+		    (!local->revalidate && (local->op_ret == 0) && 
+		     S_ISDIR(local->stbuf.st_mode))) {
+			/* Let the self heal be done here */
+			zr_unify_self_heal (frame, this, local);
+			local_dict = NULL;
+		} else {
+			/* either no self heal, or op_ret == -1 (failure) */
+			tmp_inode = local->loc1.inode;
+			unify_local_wipe (local);
+			STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+				      tmp_inode, &local->stbuf, local->dict);
+		}
+		if (local_dict) {
+			dict_unref (local_dict);
+		}
+	}
+  
+	return 0;
+}
+
+/**
+ * unify_lookup - 
+ */
+int32_t 
+unify_lookup (call_frame_t *frame,
+	      xlator_t *this,
+	      loc_t *loc,
+	      dict_t *xattr_req)
+{
+	unify_local_t *local = NULL;
+	unify_private_t *priv = this->private;
+	int16_t *list = NULL;
+	long index = 0;
+
+	if (!(loc && loc->inode)) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"%s: Argument not right", loc?loc->path:"(null)");
+		STACK_UNWIND (frame, -1, EINVAL, NULL, NULL, NULL);
+		return 0;
+	}
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	if (local->loc1.path == NULL) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, loc->inode, NULL, NULL);
+		return 0;
+	}
+
+	if (!inode_ctx_get (loc->inode, this, NULL) && 
+	    loc->inode->st_mode && 
+	    !S_ISDIR (loc->inode->st_mode)) {
+		uint64_t tmp_list = 0;
+		/* check if revalidate or fresh lookup */
+		inode_ctx_get (loc->inode, this, &tmp_list);
+		local->list = (int16_t *)(long)tmp_list;
+	}
+
+	if (local->list) {
+		list = local->list;
+		for (index = 0; list[index] != -1; index++);
+		if (index != 2) {
+			if (index < 2) {
+				gf_log (this->name, GF_LOG_ERROR,
+					"returning ESTALE for %s: file "
+					"count is %ld", loc->path, index);
+				/* Print where all the file is present */
+				for (index = 0; 
+				     local->list[index] != -1; index++) {
+					gf_log (this->name, GF_LOG_ERROR, 
+						"%s: found on %s", loc->path, 
+						priv->xl_array[list[index]]->name);
+				}
+				unify_local_wipe (local);
+				STACK_UNWIND (frame, -1, ESTALE, 
+					      NULL, NULL, NULL);
+				return 0;  
+			} else {
+				/* There are more than 2 presences */
+				/* Just log and continue */
+				gf_log (this->name, GF_LOG_ERROR,
+					"%s: file count is %ld", 
+					loc->path, index);
+				/* Print where all the file is present */
+				for (index = 0; 
+				     local->list[index] != -1; index++) {
+					gf_log (this->name, GF_LOG_ERROR, 
+						"%s: found on %s", loc->path, 
+						priv->xl_array[list[index]]->name);
+				}
+			}
+		}
+      
+		/* is revalidate */
+		local->revalidate = 1;
+      
+		for (index = 0; list[index] != -1; index++)
+			local->call_count++;
+      
+		for (index = 0; list[index] != -1; index++) {
+			char need_break = (list[index+1] == -1);
+			STACK_WIND_COOKIE (frame,
+					   unify_lookup_cbk,
+					   (void *)(long)list[index], //cookie
+					   priv->xl_array [list[index]],
+					   priv->xl_array [list[index]]->fops->lookup,
+					   loc,
+					   xattr_req);
+			if (need_break)
+				break;
+		}
+	} else {
+		if (loc->inode->st_mode) {
+			if (inode_ctx_get (loc->inode, this, NULL)) {
+				inode_ctx_get (loc->inode, this, 
+					       &local->inode_generation);
+			}
+		}
+		/* This is first call, there is no list */
+		/* call count should be all child + 1 namespace */
+		local->call_count = priv->child_count + 1;
+      
+		for (index = 0; index <= priv->child_count; index++) {
+			STACK_WIND_COOKIE (frame,
+					   unify_lookup_cbk,
+					   (void *)index, //cookie
+					   priv->xl_array[index],
+					   priv->xl_array[index]->fops->lookup,
+					   loc,
+					   xattr_req);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * unify_stat - if directory, get the stat directly from NameSpace child.
+ *     if file, check for a hint and send it only there (also to NS).
+ *     if its a fresh stat, then do it on all the nodes.
+ *
+ * NOTE: for all the call, sending cookie as xlator pointer, which will be 
+ *       used in cbk.
+ */
+int32_t
+unify_stat (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc)
+{
+	unify_local_t *local = NULL;
+	unify_private_t *priv = this->private;
+	int16_t index = 0;
+	int16_t *list = NULL;
+	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	if (local->loc1.path == NULL) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, NULL);
+		return 0;
+	}
+	local->st_ino = loc->inode->ino;
+	if (S_ISDIR (loc->inode->st_mode)) {
+		/* Directory */
+		local->call_count = 1;
+		STACK_WIND (frame, unify_buf_cbk, NS(this),
+			    NS(this)->fops->stat, loc);
+	} else {
+		/* File */
+		inode_ctx_get (loc->inode, this, &tmp_list);
+    		list = (int16_t *)(long)tmp_list;
+
+		for (index = 0; list[index] != -1; index++)
+			local->call_count++;
+    
+		for (index = 0; list[index] != -1; index++) {
+			char need_break = (list[index+1] == -1);
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[list[index]],
+				    priv->xl_array[list[index]]->fops->stat,
+				    loc);
+			if (need_break)
+				break;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * unify_access_cbk -
+ */
+int32_t
+unify_access_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+
+/**
+ * unify_access - Send request to only namespace, which has all the 
+ *      attributes set for the file.
+ */
+int32_t
+unify_access (call_frame_t *frame,
+	      xlator_t *this,
+	      loc_t *loc,
+	      int32_t mask)
+{
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	STACK_WIND (frame,
+		    unify_access_cbk,
+		    NS(this),
+		    NS(this)->fops->access,
+		    loc,
+		    mask);
+
+	return 0;
+}
+
+int32_t
+unify_mkdir_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 inode_t *inode,
+		 struct stat *buf)
+{
+	int32_t callcnt = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	inode_t *tmp_inode = NULL;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+  
+		if ((op_ret == -1) && !(priv->optimist && 
+					(op_errno == ENOENT || 
+					 op_errno == EEXIST))) {
+			/* TODO: Decrement the inode_generation of 
+			 * this->inode's parent inode, hence the missing 
+			 * directory is created properly by self-heal. 
+			 * Currently, there is no way to get the parent 
+			 * inode directly.
+			 */
+			gf_log (this->name, GF_LOG_ERROR,
+				"child(%s): path(%s): %s", 
+				priv->xl_array[(long)cookie]->name, 
+				local->loc1.path, strerror (op_errno));
+			if (op_errno != EEXIST)
+				local->failed = 1;
+			local->op_errno = op_errno;
+		}
+  
+		if (op_ret >= 0)
+			local->op_ret = 0;
+
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		if (!local->failed) {
+			inode_ctx_put (local->loc1.inode, this, 
+				       priv->inode_generation);
+		}
+		
+		tmp_inode = local->loc1.inode;
+		unify_local_wipe (local);
+
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      tmp_inode, &local->stbuf);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_ns_mkdir_cbk -
+ */
+int32_t
+unify_ns_mkdir_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    inode_t *inode,
+		    struct stat *buf)
+{
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	long index = 0;
+
+	if (op_ret == -1) {
+		/* No need to send mkdir request to other servers, 
+		 * as namespace action failed 
+		 */
+		gf_log (this->name, GF_LOG_ERROR,
+			"namespace: path(%s): %s", 
+			local->name, strerror (op_errno));
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno, inode, NULL);
+		return 0;
+	}
+  
+	/* Create one inode for this entry */
+	local->op_ret = 0;
+	local->stbuf = *buf;
+
+	local->call_count = priv->child_count;
+
+	/* Send mkdir request to all the nodes now */
+	for (index = 0; index < priv->child_count; index++) {
+		STACK_WIND_COOKIE (frame,
+				   unify_mkdir_cbk,
+				   (void *)index, //cookie
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->mkdir,
+				   &local->loc1,
+				   local->mode);
+	}
+  
+	return 0;
+}
+
+
+/**
+ * unify_mkdir -
+ */
+int32_t
+unify_mkdir (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     mode_t mode)
+{
+	unify_local_t *local = NULL;
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->mode = mode;
+
+	loc_copy (&local->loc1, loc);
+
+	if (local->loc1.path == NULL) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, NULL, NULL);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    unify_ns_mkdir_cbk,
+		    NS(this),
+		    NS(this)->fops->mkdir,
+		    loc,
+		    mode);
+	return 0;
+}
+
+/**
+ * unify_rmdir_cbk -
+ */
+int32_t
+unify_rmdir_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno)
+{
+	int32_t callcnt = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if (op_ret == 0 || (priv->optimist && (op_errno == ENOENT)))
+			local->op_ret = 0;
+		if (op_ret == -1)
+			local->op_errno = op_errno;
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_ns_rmdir_cbk -
+ */
+int32_t
+unify_ns_rmdir_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno)
+{
+	int16_t index = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+  
+	if (op_ret == -1) {
+		/* No need to send rmdir request to other servers, 
+		 * as namespace action failed 
+		 */
+		gf_log (this->name, 
+			((op_errno != ENOTEMPTY) ? 
+			 GF_LOG_ERROR : GF_LOG_DEBUG),
+			"namespace: path(%s): %s", 
+			local->loc1.path, strerror (op_errno));
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno);
+		return 0;
+	}
+
+	local->call_count = priv->child_count;
+
+	for (index = 0; index < priv->child_count; index++) {
+		STACK_WIND (frame,
+			    unify_rmdir_cbk,
+			    priv->xl_array[index],
+			    priv->xl_array[index]->fops->rmdir,
+			    &local->loc1);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_rmdir -
+ */
+int32_t
+unify_rmdir (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc)
+{
+	unify_local_t *local = NULL;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+
+	loc_copy (&local->loc1, loc);
+	if (local->loc1.path == NULL) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    unify_ns_rmdir_cbk,
+		    NS(this),
+		    NS(this)->fops->rmdir,
+		    loc);
+
+	return 0;
+}
+
+/**
+ * unify_open_cbk -
+ */
+int32_t
+unify_open_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		fd_t *fd)
+{
+	int32_t callcnt = 0;
+	unify_local_t *local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		if (op_ret >= 0) {
+			local->op_ret = op_ret;
+			if (NS(this) != (xlator_t *)cookie) {
+				/* Store child node's ptr, used in 
+				   all the f*** / FileIO calls */
+				fd_ctx_set (fd, this, (uint64_t)(long)cookie);
+			}
+		}
+		if (op_ret == -1) {
+			local->op_errno = op_errno;
+			local->failed = 1;
+		}
+		callcnt = --local->call_count;
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		if ((local->failed == 1) && (local->op_ret >= 0)) {
+			local->call_count = 1;
+			/* return -1 to user */
+			local->op_ret = -1;
+			//local->op_errno = EIO; 
+      
+			if (!fd_ctx_get (local->fd, this, NULL)) {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"Open success on child node, "
+					"failed on namespace");
+			} else {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"Open success on namespace, "
+					"failed on child node");
+			}
+		}
+
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, 
+			      local->op_errno, local->fd);
+	}
+
+	return 0;
+}
+
+#ifdef GF_DARWIN_HOST_OS
+/**
+ * unify_create_lookup_cbk - 
+ */
+int32_t 
+unify_open_lookup_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno,
+		       inode_t *inode,
+		       struct stat *buf,
+		       dict_t *dict)
+{
+	int32_t callcnt = 0;
+	int16_t index = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if ((op_ret == -1) && (op_errno != ENOENT)) {
+			gf_log (this->name, GF_LOG_ERROR,
+				"child(%s): path(%s): %s", 
+				priv->xl_array[(long)cookie]->name, 
+				local->loc1.path, strerror (op_errno));
+			local->op_errno = op_errno;
+		}
+    
+		if (op_ret >= 0) {
+			local->op_ret = op_ret; 
+			local->index++;
+			if (NS(this) == priv->xl_array[(long)cookie]) {
+				local->list[0] = (int16_t)(long)cookie;
+			} else {
+				local->list[1] = (int16_t)(long)cookie;
+			}
+			if (S_ISDIR (buf->st_mode))
+				local->failed = 1;
+		}
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		int16_t file_list[3] = {0,};
+		local->op_ret = -1;
+
+		file_list[0] = local->list[0];
+		file_list[1] = local->list[1];
+		file_list[2] = -1;
+
+		if (local->index != 2) {
+			/* Lookup failed, can't do open */
+			gf_log (this->name, GF_LOG_ERROR,
+				"%s: present on %d nodes", 
+				local->name, local->index);
+
+			if (local->index < 2) {
+				unify_local_wipe (local);
+				gf_log (this->name, GF_LOG_ERROR,
+					"returning as file found on less "
+					"than 2 nodes");
+				STACK_UNWIND (frame, local->op_ret, 
+					      local->op_errno, local->fd);
+				return 0;
+			}
+		}
+
+		if (local->failed) {
+			/* Open on directory, return EISDIR */
+			unify_local_wipe (local);
+			STACK_UNWIND (frame, -1, EISDIR, local->fd);
+			return 0;
+		}
+
+		/* Everything is perfect :) */    
+		local->call_count = 2;
+    
+		for (index = 0; file_list[index] != -1; index++) {
+			char need_break = (file_list[index+1] == -1);
+			STACK_WIND_COOKIE (frame,
+					   unify_open_cbk,
+					   priv->xl_array[file_list[index]],
+					   priv->xl_array[file_list[index]],
+					   priv->xl_array[file_list[index]]->fops->open,
+					   &local->loc1,
+					   local->flags,
+					   local->fd);
+			if (need_break)
+				break;
+		}
+	}
+
+	return 0;
+}
+
+
+int32_t
+unify_open_readlink_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno,
+			 const char *path)
+{
+	int16_t index = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+
+	if (op_ret == -1) {
+		STACK_UNWIND (frame, -1, ENOENT);
+		return 0;
+	}
+
+	if (path[0] == '/') {
+		local->name = strdup (path);
+		ERR_ABORT (local->name);
+	} else {
+		char *tmp_str = strdup (local->loc1.path);
+		char *tmp_base = dirname (tmp_str);
+		local->name = CALLOC (1, ZR_PATH_MAX);
+		strcpy (local->name, tmp_base);
+		strncat (local->name, "/", 1);
+		strcat (local->name, path);
+		FREE (tmp_str);
+	}
+  
+	local->list = CALLOC (1, sizeof (int16_t) * 3);
+	ERR_ABORT (local->list);
+	local->call_count = priv->child_count + 1;
+	local->op_ret = -1;
+	for (index = 0; index <= priv->child_count; index++) {
+		/* Send the lookup to all the nodes including namespace */
+		STACK_WIND_COOKIE (frame,
+				   unify_open_lookup_cbk,
+				   (void *)(long)index,
+				   priv->xl_array[index],
+				   priv->xl_array[index]->fops->lookup,
+				   &local->loc1,
+				   NULL);
+	}
+
+	return 0;
+}
+#endif /* GF_DARWIN_HOST_OS */
+
+/**
+ * unify_open - 
+ */
+int32_t
+unify_open (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc,
+	    int32_t flags,
+	    fd_t *fd)
+{
+	unify_private_t *priv = this->private;
+	unify_local_t *local = NULL;
+	int16_t *list = NULL;
+	int16_t index = 0;
+	int16_t file_list[3] = {0,};
+	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Init */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	local->fd    = fd;
+	local->flags = flags;
+	inode_ctx_get (loc->inode, this, &tmp_list);
+	list = (int16_t *)(long)tmp_list;
+
+	local->list = list;
+	file_list[0] = priv->child_count; /* Thats namespace */
+	file_list[2] = -1;
+	for (index = 0; list[index] != -1; index++) {
+		local->call_count++;
+		if (list[index] != priv->child_count)
+			file_list[1] = list[index];
+	}
+
+	if (local->call_count != 2) {
+		/* If the lookup was done for file */
+		gf_log (this->name, GF_LOG_ERROR,
+			"%s: entry_count is %d",
+			loc->path, local->call_count);
+		for (index = 0; local->list[index] != -1; index++)
+			gf_log (this->name, GF_LOG_ERROR, "%s: found on %s",
+				loc->path, priv->xl_array[list[index]]->name);
+
+		if (local->call_count < 2) {
+			gf_log (this->name, GF_LOG_ERROR,
+				"returning EIO as file found on onlyone node");
+			STACK_UNWIND (frame, -1, EIO, fd);
+			return 0;
+		}
+	}
+
+#ifdef GF_DARWIN_HOST_OS
+	/* Handle symlink here */
+	if (S_ISLNK (loc->inode->st_mode)) {
+		/* Callcount doesn't matter here */
+		STACK_WIND (frame,
+			    unify_open_readlink_cbk,
+			    NS(this),
+			    NS(this)->fops->readlink,
+			    loc, ZR_PATH_MAX);
+		return 0;
+	}
+#endif /* GF_DARWIN_HOST_OS */
+
+	local->call_count = 2;
+	for (index = 0; file_list[index] != -1; index++) {
+		char need_break = (file_list[index+1] == -1);
+		STACK_WIND_COOKIE (frame,
+				   unify_open_cbk,
+				   priv->xl_array[file_list[index]], //cookie
+				   priv->xl_array[file_list[index]],
+				   priv->xl_array[file_list[index]]->fops->open,
+				   loc,
+				   flags,
+				   fd);
+		if (need_break)
+			break;
+	}
+
+	return 0;
+}
+
+
+int32_t 
+unify_create_unlink_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno)
+{
+	unify_local_t *local = frame->local;
+	inode_t *inode = local->loc1.inode;
+
+	unify_local_wipe (local);
+
+	STACK_UNWIND (frame, local->op_ret, local->op_errno, local->fd, 
+		      inode, &local->stbuf);
+  
+	return 0;
+}
+
+/**
+ * unify_create_open_cbk -
+ */
+int32_t
+unify_create_open_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno,
+		       fd_t *fd)
+{
+	int ret = 0;
+	int32_t callcnt = 0;
+	unify_local_t *local = frame->local;
+	inode_t *inode = NULL;
+	xlator_t *child = NULL;
+	uint64_t tmp_value = 0;
+
+	LOCK (&frame->lock);
+	{
+		if (op_ret >= 0) {
+			local->op_ret = op_ret;
+			if (NS(this) != (xlator_t *)cookie) {
+				/* Store child node's ptr, used in all 
+				   the f*** / FileIO calls */
+				/* TODO: log on failure */
+				ret = fd_ctx_get (fd, this, &tmp_value);
+				cookie = (void *)(long)tmp_value;
+			} else {
+				/* NOTE: open successful on namespace.
+				 *       fd's ctx can be used to identify open 
+				 *       failure on storage subvolume. cool 
+				 *       ide ;) */
+				local->failed = 0;
+			}
+		} else {
+			gf_log (this->name, GF_LOG_ERROR,
+				"child(%s): path(%s): %s", 
+				((xlator_t *)cookie)->name,
+				local->loc1.path, strerror (op_errno));
+			local->op_errno = op_errno;
+			local->failed = 1;
+		}
+		callcnt = --local->call_count;
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		if (local->failed == 1 && (local->op_ret >= 0)) {
+			local->call_count = 1;
+			/* return -1 to user */
+			local->op_ret = -1;
+			local->op_errno = EIO;
+			local->fd = fd;
+			local->call_count = 1;
+
+			if (!fd_ctx_get (local->fd, this, &tmp_value)) {
+				child = (xlator_t *)(long)tmp_value;
+
+				gf_log (this->name, GF_LOG_ERROR, 
+					"Create success on child node, "
+					"failed on namespace");
+
+				STACK_WIND (frame,
+					    unify_create_unlink_cbk,
+					    child,
+					    child->fops->unlink,
+					    &local->loc1);
+			} else {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"Create success on namespace, "
+					"failed on child node");
+
+				STACK_WIND (frame,
+					    unify_create_unlink_cbk,
+					    NS(this),
+					    NS(this)->fops->unlink,
+					    &local->loc1);
+			}
+			return 0;
+		}
+		inode = local->loc1.inode;
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, fd,
+			      inode, &local->stbuf);
+	}
+	return 0;
+}
+
+/**
+ * unify_create_lookup_cbk - 
+ */
+int32_t 
+unify_create_lookup_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno,
+			 inode_t *inode,
+			 struct stat *buf,
+			 dict_t *dict)
+{
+	int32_t callcnt = 0;
+	int16_t index = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if (op_ret == -1) {
+			gf_log (this->name, GF_LOG_ERROR,
+				"child(%s): path(%s): %s", 
+				priv->xl_array[(long)cookie]->name, 
+				local->loc1.path, strerror (op_errno));
+			local->op_errno = op_errno;
+			local->failed = 1;
+		}
+
+		if (op_ret >= 0) {
+			local->op_ret = op_ret; 
+			local->list[local->index++] = (int16_t)(long)cookie;
+			if (NS(this) == priv->xl_array[(long)cookie]) {
+				local->st_ino = buf->st_ino;
+			} else {
+				local->stbuf = *buf;
+			}
+		}
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		int16_t *list = local->list;
+		int16_t file_list[3] = {0,};
+		local->op_ret = -1;
+
+		local->list [local->index] = -1;
+		file_list[0] = list[0];
+		file_list[1] = list[1];
+		file_list[2] = -1;
+
+		local->stbuf.st_ino = local->st_ino;
+		/* TODO: log on failure */
+		inode_ctx_put (local->loc1.inode, this, 
+			       (uint64_t)(long)local->list);
+
+		if (local->index != 2) {
+			/* Lookup failed, can't do open */
+			gf_log (this->name, GF_LOG_ERROR,
+				"%s: present on %d nodes", 
+				local->loc1.path, local->index);
+			file_list[0] = priv->child_count;
+			for (index = 0; list[index] != -1; index++) {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"%s: found on %s", local->loc1.path, 
+					priv->xl_array[list[index]]->name);
+				if (list[index] != priv->child_count)
+					file_list[1] = list[index];
+			}
+
+			if (local->index < 2) {
+				unify_local_wipe (local);
+				gf_log (this->name, GF_LOG_ERROR,
+					"returning EIO as file found on "
+					"only one node");
+				STACK_UNWIND (frame, -1, EIO, 
+					      local->fd, inode, NULL);
+				return 0;
+			}
+		}
+		/* Everything is perfect :) */    
+		local->call_count = 2;
+    
+		for (index = 0; file_list[index] != -1; index++) {
+			char need_break = (file_list[index+1] == -1);
+			STACK_WIND_COOKIE (frame,
+					   unify_create_open_cbk,
+					   priv->xl_array[file_list[index]],
+					   priv->xl_array[file_list[index]],
+					   priv->xl_array[file_list[index]]->fops->open,
+					   &local->loc1,
+					   local->flags,
+					   local->fd);
+			if (need_break)
+				break;
+		}
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_create_cbk -
+ */
+int32_t
+unify_create_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno,
+		  fd_t *fd,
+		  inode_t *inode,
+		  struct stat *buf)
+{
+	int ret = 0;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+	inode_t *tmp_inode = NULL;
+
+	if (op_ret == -1) {
+		/* send unlink () on Namespace */
+		local->op_errno = op_errno;
+		local->op_ret = -1;
+		local->call_count = 1;
+		gf_log (this->name, GF_LOG_ERROR,
+			"create failed on %s (file %s, error %s), "
+			"sending unlink to namespace", 
+			prev_frame->this->name, 
+			local->loc1.path, strerror (op_errno));
+
+		STACK_WIND (frame,
+			    unify_create_unlink_cbk,
+			    NS(this),
+			    NS(this)->fops->unlink,
+			    &local->loc1);
+
+		return 0;
+	}
+
+	if (op_ret >= 0) {
+		local->op_ret = op_ret;
+		local->stbuf = *buf;
+		/* Just inode number should be from NS node */
+		local->stbuf.st_ino = local->st_ino;
+
+		/* TODO: log on failure */
+		ret = fd_ctx_set (fd, this, (uint64_t)(long)prev_frame->this);
+	}
+  
+	tmp_inode = local->loc1.inode;
+	unify_local_wipe (local);
+	STACK_UNWIND (frame, local->op_ret, local->op_errno, local->fd, 
+		      tmp_inode, &local->stbuf);
+
+	return 0;
+}
+
+/**
+ * unify_ns_create_cbk -
+ * 
+ */
+int32_t
+unify_ns_create_cbk (call_frame_t *frame,
+		     void *cookie,
+		     xlator_t *this,
+		     int32_t op_ret,
+		     int32_t op_errno,
+		     fd_t *fd,
+		     inode_t *inode,
+		     struct stat *buf)
+{
+	struct sched_ops *sched_ops = NULL;
+	xlator_t *sched_xl = NULL;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int16_t *list = NULL;
+	int16_t index = 0;
+
+	if (op_ret == -1) {
+		/* No need to send create request to other servers, as 
+		   namespace action failed. Handle exclusive create here. */
+		if ((op_errno != EEXIST) || 
+		    ((op_errno == EEXIST) && 
+		     ((local->flags & O_EXCL) == O_EXCL))) {
+			/* If its just a create call without O_EXCL, 
+			   don't do this */
+			gf_log (this->name, GF_LOG_ERROR,
+				"namespace: path(%s): %s", 
+				local->loc1.path, strerror (op_errno));
+			unify_local_wipe (local);
+			STACK_UNWIND (frame, op_ret, op_errno, fd, inode, buf);
+			return 0;
+		}
+	}
+  
+	if (op_ret >= 0) {
+		/* Get the inode number from the NS node */
+		local->st_ino = buf->st_ino;
+  
+		local->op_ret = -1;
+
+		/* Start the mapping list */
+		list = CALLOC (1, sizeof (int16_t) * 3);
+		ERR_ABORT (list);
+		inode_ctx_put (inode, this, (uint64_t)(long)list);
+		list[0] = priv->child_count;
+		list[2] = -1;
+
+		/* This means, file doesn't exist anywhere in the Filesystem */
+		sched_ops = priv->sched_ops;
+
+		/* Send create request to the scheduled node now */
+		sched_xl = sched_ops->schedule (this, local->loc1.path);
+		if (sched_xl == NULL)
+		{
+			/* send unlink () on Namespace */
+			local->op_errno = ENOTCONN;
+			local->op_ret = -1;
+			local->call_count = 1;
+			gf_log (this->name, GF_LOG_ERROR,
+				"no node online to schedule create:(file %s) "
+				"sending unlink to namespace", 
+				(local->loc1.path)?local->loc1.path:"");
+
+			STACK_WIND (frame,
+				    unify_create_unlink_cbk,
+				    NS(this),
+				    NS(this)->fops->unlink,
+				    &local->loc1);
+	
+			return 0;
+		}
+
+		for (index = 0; index < priv->child_count; index++)
+			if (sched_xl == priv->xl_array[index])
+				break;
+		list[1] = index;
+
+		STACK_WIND (frame, unify_create_cbk,
+			    sched_xl, sched_xl->fops->create,
+			    &local->loc1, local->flags, local->mode, fd);
+	} else {
+		/* File already exists, and there is no O_EXCL flag */
+
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"File(%s) already exists on namespace, sending "
+			"open instead", local->loc1.path);
+
+		local->list = CALLOC (1, sizeof (int16_t) * 3);
+		ERR_ABORT (local->list);
+		local->call_count = priv->child_count + 1;
+		local->op_ret = -1;
+		for (index = 0; index <= priv->child_count; index++) {
+			/* Send lookup() to all nodes including namespace */
+			STACK_WIND_COOKIE (frame,
+					   unify_create_lookup_cbk,
+					   (void *)(long)index,
+					   priv->xl_array[index],
+					   priv->xl_array[index]->fops->lookup,
+					   &local->loc1,
+					   NULL);
+		}
+	}
+	return 0;
+}
+
+/**
+ * unify_create - create a file in global namespace first, so other 
+ *    clients can see them. Create the file in storage nodes in background.
+ */
+int32_t
+unify_create (call_frame_t *frame,
+	      xlator_t *this,
+	      loc_t *loc,
+	      int32_t flags,
+	      mode_t mode,
+	      fd_t *fd)
+{
+	unify_local_t *local = NULL;
+  
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->mode = mode;
+	local->flags = flags;
+	local->fd = fd;
+
+	loc_copy (&local->loc1, loc);
+	if (local->loc1.path == NULL) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, fd, loc->inode, NULL);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    unify_ns_create_cbk,
+		    NS(this),
+		    NS(this)->fops->create,
+		    loc,
+		    flags | O_EXCL,
+		    mode,
+		    fd);
+  
+	return 0;
+}
+
+
+/**
+ * unify_opendir_cbk - 
+ */
+int32_t
+unify_opendir_cbk (call_frame_t *frame,
+		   void *cookie,
+		   xlator_t *this,
+		   int32_t op_ret,
+		   int32_t op_errno,
+		   fd_t *fd)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, fd);
+
+	return 0;
+}
+
+/** 
+ * unify_opendir -
+ */
+int32_t
+unify_opendir (call_frame_t *frame,
+	       xlator_t *this,
+	       loc_t *loc,
+	       fd_t *fd)
+{
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	STACK_WIND (frame, unify_opendir_cbk,
+		    NS(this), NS(this)->fops->opendir, loc, fd);
+
+	return 0;
+}
+
+
+/**
+ * unify_chmod - 
+ */
+int32_t
+unify_chmod (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     mode_t mode)
+{
+	unify_local_t *local = NULL;
+	unify_private_t *priv = this->private;
+	int32_t index = 0;
+	int32_t callcnt = 0;
+	uint64_t tmp_list = 0;
+		
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+
+	loc_copy (&local->loc1, loc);
+	local->st_ino = loc->inode->ino;
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+		local->call_count = priv->child_count + 1;
+      
+		for (index = 0; index < (priv->child_count + 1); index++) {
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->chmod,
+				    loc, mode);
+		}    
+	} else {
+		inode_ctx_get (loc->inode, this, &tmp_list);
+		local->list = (int16_t *)(long)tmp_list;
+
+		for (index = 0; local->list[index] != -1; index++) {
+			local->call_count++;
+			callcnt++;
+		}
+      
+		for (index = 0; local->list[index] != -1; index++) {
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[local->list[index]],
+				    priv->xl_array[local->list[index]]->fops->chmod,
+				    loc,
+				    mode);
+			if (!--callcnt)
+				break;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * unify_chown - 
+ */
+int32_t
+unify_chown (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     uid_t uid,
+	     gid_t gid)
+{
+	unify_local_t *local = NULL;
+	unify_private_t *priv = this->private;
+	int32_t index = 0;
+	int32_t callcnt = 0;
+  	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	local->st_ino = loc->inode->ino;
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+		local->call_count = priv->child_count + 1;
+      
+		for (index = 0; index < (priv->child_count + 1); index++) {
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->chown,
+				    loc, uid, gid);
+		}    
+	} else {
+		inode_ctx_get (loc->inode, this, &tmp_list);
+		local->list = (int16_t *)(long)tmp_list;
+
+		for (index = 0; local->list[index] != -1; index++) {
+			local->call_count++;
+			callcnt++;
+		}
+      
+		for (index = 0; local->list[index] != -1; index++) {
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[local->list[index]],
+				    priv->xl_array[local->list[index]]->fops->chown,
+				    loc, uid, gid);
+			if (!--callcnt)
+				break;
+		}
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_truncate_cbk - 
+ */
+int32_t
+unify_truncate_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    struct stat *buf)
+{
+	int32_t callcnt = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+    
+		if (op_ret == -1) {
+			gf_log (this->name, GF_LOG_ERROR,
+				"child(%s): path(%s): %s", 
+				prev_frame->this->name, 
+				(local->loc1.path)?local->loc1.path:"", 
+				strerror (op_errno));
+			local->op_errno = op_errno;
+			if (!((op_errno == ENOENT) && priv->optimist))
+				local->op_ret = -1;
+		}
+
+		if (op_ret >= 0) {
+			if (NS (this) == prev_frame->this) {
+				local->st_ino = buf->st_ino;
+				/* If the entry is directory, get the 
+				   stat from NS node */
+				if (S_ISDIR (buf->st_mode) || 
+				    !local->stbuf.st_blksize) {
+					local->stbuf = *buf;
+				}
+			}
+
+			if ((!S_ISDIR (buf->st_mode)) && 
+			    (NS (this) != prev_frame->this)) {
+				/* If file, take the stat info from 
+				   Storage node. */
+				local->stbuf = *buf;
+			}
+		}
+	}
+	UNLOCK (&frame->lock);
+    
+	if (!callcnt) {
+		if (local->st_ino)
+			local->stbuf.st_ino = local->st_ino;
+		else
+			local->op_ret = -1;
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      &local->stbuf);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_truncate - 
+ */
+int32_t
+unify_truncate (call_frame_t *frame,
+		xlator_t *this,
+		loc_t *loc,
+		off_t offset)
+{
+	unify_local_t *local = NULL;
+	unify_private_t *priv = this->private;
+	int32_t index = 0;
+	int32_t callcnt = 0;
+  	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	local->st_ino = loc->inode->ino;
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+		local->call_count = 1;
+      
+		STACK_WIND (frame,
+			    unify_buf_cbk,
+			    NS(this),
+			    NS(this)->fops->stat,
+			    loc);
+	} else {
+		local->op_ret = 0;
+		inode_ctx_get (loc->inode, this, &tmp_list);
+		local->list = (int16_t *)(long)tmp_list;
+
+		for (index = 0; local->list[index] != -1; index++) {
+			local->call_count++;
+			callcnt++;
+		}
+      
+		/* Don't send truncate to NS node */
+		STACK_WIND (frame, unify_truncate_cbk, NS(this),
+			    NS(this)->fops->stat, loc);
+		callcnt--;
+
+		for (index = 0; local->list[index] != -1; index++) {
+			if (NS(this) != priv->xl_array[local->list[index]]) {
+				STACK_WIND (frame,
+					    unify_truncate_cbk,
+					    priv->xl_array[local->list[index]],
+					    priv->xl_array[local->list[index]]->fops->truncate,
+					    loc,
+					    offset);
+				if (!--callcnt)
+					break;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * unify_utimens - 
+ */
+int32_t 
+unify_utimens (call_frame_t *frame,
+	       xlator_t *this,
+	       loc_t *loc,
+	       struct timespec tv[2])
+{
+	unify_local_t *local = NULL;
+	unify_private_t *priv = this->private;
+	int32_t index = 0;
+	int32_t callcnt = 0;
+  	uint64_t tmp_list = 0;
+  
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	local->st_ino = loc->inode->ino;
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+		local->call_count = priv->child_count + 1;
+      
+		for (index = 0; index < (priv->child_count + 1); index++) {
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->utimens,
+				    loc, tv);
+		}
+	} else {
+		inode_ctx_get (loc->inode, this, &tmp_list);
+		local->list = (int16_t *)(long)tmp_list;
+
+		for (index = 0; local->list[index] != -1; index++) {
+			local->call_count++;
+			callcnt++;
+		}
+      
+		for (index = 0; local->list[index] != -1; index++) {
+			STACK_WIND (frame,
+				    unify_buf_cbk,
+				    priv->xl_array[local->list[index]],
+				    priv->xl_array[local->list[index]]->fops->utimens,
+				    loc,
+				    tv);
+			if (!--callcnt)
+				break;
+		}
+	}
+  
+	return 0;
+}
+
+/**
+ * unify_readlink_cbk - 
+ */
+int32_t
+unify_readlink_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    const char *path)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, path);
+	return 0;
+}
+
+/**
+ * unify_readlink - Read the link only from the storage node.
+ */
+int32_t
+unify_readlink (call_frame_t *frame,
+		xlator_t *this,
+		loc_t *loc,
+		size_t size)
+{
+	unify_private_t *priv = this->private;
+	int32_t entry_count = 0;
+	int16_t *list = NULL;
+	int16_t index = 0;
+  	uint64_t tmp_list = 0;
+  
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+	
+	inode_ctx_get (loc->inode, this, &tmp_list);
+	list = (int16_t *)(long)tmp_list;
+
+	for (index = 0; list[index] != -1; index++)
+		entry_count++;
+
+	if (entry_count >= 2) {
+		for (index = 0; list[index] != -1; index++) {
+			if (priv->xl_array[list[index]] != NS(this)) {
+				STACK_WIND (frame,
+					    unify_readlink_cbk,
+					    priv->xl_array[list[index]],
+					    priv->xl_array[list[index]]->fops->readlink,
+					    loc,
+					    size);
+				break;
+			}
+		}
+	} else {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"returning ENOENT, no softlink files found "
+			"on storage node");
+		STACK_UNWIND (frame, -1, ENOENT, NULL);
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_unlink_cbk - 
+ */
+int32_t
+unify_unlink_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno)
+{
+	int32_t callcnt = 0;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if (op_ret == 0  || ((op_errno == ENOENT) && priv->optimist))
+			local->op_ret = 0;
+		if (op_ret == -1)
+			local->op_errno = op_errno;
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno);
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_unlink - 
+ */
+int32_t
+unify_unlink (call_frame_t *frame,
+	      xlator_t *this,
+	      loc_t *loc)
+{
+	unify_private_t *priv = this->private;
+	unify_local_t *local = NULL;
+	int16_t *list = NULL;
+	int16_t index = 0;
+  	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+
+	inode_ctx_get (loc->inode, this, &tmp_list);
+	list = (int16_t *)(long)tmp_list;
+
+	for (index = 0; list[index] != -1; index++)
+		local->call_count++;
+
+	if (local->call_count) {
+		for (index = 0; list[index] != -1; index++) {
+			char need_break = (list[index+1] == -1);
+			STACK_WIND (frame,
+				    unify_unlink_cbk,
+				    priv->xl_array[list[index]],
+				    priv->xl_array[list[index]]->fops->unlink,
+				    loc);
+			if (need_break)
+				break;
+		}
+	} else {
+		gf_log (this->name, GF_LOG_ERROR,
+			"%s: returning ENOENT", loc->path);
+		STACK_UNWIND (frame, -1, ENOENT);
+	}
+
+	return 0;
+}
+
+
+/**
+ * unify_readv_cbk - 
+ */
+int32_t
+unify_readv_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 struct iovec *vector,
+		 int32_t count,
+		 struct stat *stbuf)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, vector, count, stbuf);
+	return 0;
+}
+
+/**
+ * unify_readv - 
+ */
+int32_t
+unify_readv (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd,
+	     size_t size,
+	     off_t offset)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame,
+		    unify_readv_cbk,
+		    child,
+		    child->fops->readv,
+		    fd,
+		    size,
+		    offset);
+
+
+	return 0;
+}
+
+/**
+ * unify_writev_cbk - 
+ */
+int32_t
+unify_writev_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno,
+		  struct stat *stbuf)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, stbuf);
+	return 0;
+}
+
+/**
+ * unify_writev - 
+ */
+int32_t
+unify_writev (call_frame_t *frame,
+	      xlator_t *this,
+	      fd_t *fd,
+	      struct iovec *vector,
+	      int32_t count,
+	      off_t off)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame,
+		    unify_writev_cbk,
+		    child,
+		    child->fops->writev,
+		    fd,
+		    vector,
+		    count,
+		    off);
+
+	return 0;
+}
+
+/**
+ * unify_ftruncate -
+ */
+int32_t
+unify_ftruncate (call_frame_t *frame,
+		 xlator_t *this,
+		 fd_t *fd,
+		 off_t offset)
+{
+	xlator_t *child = NULL;
+	unify_local_t *local = NULL;
+	uint64_t tmp_child = 0;
+
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR(fd);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->op_ret = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	local->call_count = 2;
+  
+	STACK_WIND (frame, unify_truncate_cbk, 
+		    child, child->fops->ftruncate,
+		    fd, offset);
+  
+	STACK_WIND (frame, unify_truncate_cbk, 
+		    NS(this), NS(this)->fops->fstat,
+		    fd);
+  
+	return 0;
+}
+
+
+/**
+ * unify_fchmod - 
+ */
+int32_t 
+unify_fchmod (call_frame_t *frame,
+	      xlator_t *this,
+	      fd_t *fd,
+	      mode_t mode)
+{
+	unify_local_t *local = NULL;
+	xlator_t *child = NULL;	
+	uint64_t tmp_child = 0;
+
+	UNIFY_CHECK_FD_AND_UNWIND_ON_ERR(fd);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->st_ino = fd->inode->ino;
+
+	if (!fd_ctx_get (fd, this, &tmp_child)) {
+		/* If its set, then its file */
+		child = (xlator_t *)(long)tmp_child;		     
+
+		local->call_count = 2;
+
+		STACK_WIND (frame, unify_buf_cbk, child, 
+			    child->fops->fchmod, fd, mode);
+
+		STACK_WIND (frame, unify_buf_cbk, NS(this),	
+			    NS(this)->fops->fchmod, fd, mode);
+
+	} else {
+		/* this is an directory */
+		local->call_count = 1;
+    
+		STACK_WIND (frame, unify_buf_cbk,
+			    NS(this), NS(this)->fops->fchmod, fd, mode);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_fchown - 
+ */
+int32_t 
+unify_fchown (call_frame_t *frame,
+	      xlator_t *this,
+	      fd_t *fd,
+	      uid_t uid,
+	      gid_t gid)
+{
+	unify_local_t *local = NULL;
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	UNIFY_CHECK_FD_AND_UNWIND_ON_ERR(fd);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->st_ino = fd->inode->ino;
+
+	if (!fd_ctx_get (fd, this, &tmp_child)) {
+		/* If its set, then its file */
+		child = (xlator_t *)(long)tmp_child;		     
+
+		local->call_count = 2;
+
+		STACK_WIND (frame, unify_buf_cbk, child,
+			    child->fops->fchown, fd, uid, gid);
+
+		STACK_WIND (frame, unify_buf_cbk, NS(this),
+			    NS(this)->fops->fchown,	fd, uid, gid);
+	} else {
+		local->call_count = 1;
+    
+		STACK_WIND (frame, unify_buf_cbk,
+			    NS(this), NS(this)->fops->fchown,
+			    fd, uid, gid);
+	}
+  
+	return 0;
+}
+
+/**
+ * unify_flush_cbk - 
+ */
+int32_t
+unify_flush_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+/**
+ * unify_flush -
+ */
+int32_t
+unify_flush (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame, unify_flush_cbk, child, 
+		    child->fops->flush, fd);
+
+	return 0;
+}
+
+
+/**
+ * unify_fsync_cbk - 
+ */
+int32_t
+unify_fsync_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+/**
+ * unify_fsync - 
+ */
+int32_t
+unify_fsync (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd,
+	     int32_t flags)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame, unify_fsync_cbk, child,
+		    child->fops->fsync, fd, flags);
+
+	return 0;
+}
+
+/**
+ * unify_fstat - Send fstat FOP to Namespace only if its directory, and to 
+ *     both namespace and the storage node if its a file.
+ */
+int32_t
+unify_fstat (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd)
+{
+	unify_local_t *local = NULL;
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	UNIFY_CHECK_FD_AND_UNWIND_ON_ERR(fd);
+
+	INIT_LOCAL (frame, local);
+	local->st_ino = fd->inode->ino;
+
+	if (!fd_ctx_get (fd, this, &tmp_child)) {
+		/* If its set, then its file */
+		child = (xlator_t *)(long)tmp_child;		     
+		local->call_count = 2;
+
+		STACK_WIND (frame, unify_buf_cbk, child,
+			    child->fops->fstat, fd);
+
+		STACK_WIND (frame, unify_buf_cbk, NS(this),
+			    NS(this)->fops->fstat, fd);
+
+	} else {
+		/* this is an directory */
+		local->call_count = 1;
+		STACK_WIND (frame, unify_buf_cbk, NS(this),
+			    NS(this)->fops->fstat, fd);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_getdents_cbk - 
+ */
+int32_t
+unify_getdents_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    dir_entry_t *entry,
+		    int32_t count)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, entry, count);
+	return 0;
+}
+
+/**
+ * unify_getdents - send the FOP request to all the nodes.
+ */
+int32_t
+unify_getdents (call_frame_t *frame,
+		xlator_t *this,
+		fd_t *fd,
+		size_t size,
+		off_t offset,
+		int32_t flag)
+{
+	UNIFY_CHECK_FD_AND_UNWIND_ON_ERR (fd);
+
+	STACK_WIND (frame, unify_getdents_cbk, NS(this),
+		    NS(this)->fops->getdents, fd, size, offset, flag);
+
+	return 0;
+}
+
+
+/**
+ * unify_readdir_cbk - 
+ */
+int32_t
+unify_readdir_cbk (call_frame_t *frame,
+		   void *cookie,
+		   xlator_t *this,
+		   int32_t op_ret,
+		   int32_t op_errno,
+		   gf_dirent_t *buf)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, buf);
+
+	return 0;
+}
+
+/**
+ * unify_readdir - send the FOP request to all the nodes.
+ */
+int32_t
+unify_readdir (call_frame_t *frame,
+	       xlator_t *this,
+	       fd_t *fd,
+	       size_t size,
+	       off_t offset)
+{
+	UNIFY_CHECK_FD_AND_UNWIND_ON_ERR (fd);
+
+	STACK_WIND (frame, unify_readdir_cbk, NS(this),
+		    NS(this)->fops->readdir, fd, size, offset);
+
+	return 0;
+}
+
+
+/**
+ * unify_fsyncdir_cbk - 
+ */
+int32_t
+unify_fsyncdir_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+
+	return 0;
+}
+
+/**
+ * unify_fsyncdir -
+ */
+int32_t
+unify_fsyncdir (call_frame_t *frame,
+		xlator_t *this,
+		fd_t *fd,
+		int32_t flags)
+{
+	UNIFY_CHECK_FD_AND_UNWIND_ON_ERR (fd);
+
+	STACK_WIND (frame, unify_fsyncdir_cbk,
+		    NS(this), NS(this)->fops->fsyncdir, fd, flags);
+
+	return 0;
+}
+
+/**
+ * unify_lk_cbk - UNWIND frame with the proper return arguments.
+ */
+int32_t
+unify_lk_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno,
+	      struct flock *lock)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, lock);
+	return 0;
+}
+
+/**
+ * unify_lk - Send it to all the storage nodes, (should be 1) which has file.
+ */
+int32_t
+unify_lk (call_frame_t *frame,
+	  xlator_t *this,
+	  fd_t *fd,
+	  int32_t cmd,
+	  struct flock *lock)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame, unify_lk_cbk, child,
+		    child->fops->lk, fd, cmd, lock);
+
+	return 0;
+}
+
+
+int32_t
+unify_setxattr_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno);
+
+static int32_t
+unify_setxattr_file_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno)
+{
+	unify_private_t *private = this->private;
+	unify_local_t *local = frame->local;
+	xlator_t *sched_xl = NULL;
+	struct sched_ops *sched_ops = NULL;
+
+	if (op_ret == -1) {
+		if (!ENOTSUP)
+			gf_log (this->name, GF_LOG_ERROR,
+				"setxattr with XATTR_CREATE on ns: "
+				"path(%s) key(%s): %s",
+				local->loc1.path, local->name, 
+				strerror (op_errno));
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno);
+		return 0;
+	} 
+
+	LOCK (&frame->lock);
+	{
+		local->failed = 0;
+		local->op_ret = 0;
+		local->op_errno = 0;
+		local->call_count = 1;
+	}
+	UNLOCK (&frame->lock);
+
+	/* schedule XATTR_CREATE on one of the child node */
+	sched_ops = private->sched_ops;
+    
+	/* Send create request to the scheduled node now */
+	sched_xl = sched_ops->schedule (this, local->name); 
+	if (!sched_xl) {
+		STACK_UNWIND (frame, -1, ENOTCONN);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    unify_setxattr_cbk,
+		    sched_xl,
+		    sched_xl->fops->setxattr,
+		    &local->loc1,
+		    local->dict,
+		    local->flags);
+	return 0;
+}
+
+/**
+ * unify_setxattr_cbk - When all the child nodes return, UNWIND frame.
+ */
+int32_t
+unify_setxattr_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno)
+{
+	int32_t callcnt = 0;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+	dict_t *dict = NULL;
+
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+    
+		if (op_ret == -1) {
+			gf_log (this->name, (((op_errno == ENOENT) || 
+					      (op_errno == ENOTSUP))? 
+					     GF_LOG_DEBUG : GF_LOG_ERROR), 
+				"child(%s): path(%s): %s", 
+				prev_frame->this->name, 
+				(local->loc1.path)?local->loc1.path:"", 
+				strerror (op_errno));
+			if (local->failed == -1) {
+				local->failed = 1;
+			}
+			local->op_errno = op_errno;
+		} else {
+			local->failed = 0;
+			local->op_ret = op_ret;
+		}
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		if (local->failed && local->name && 
+		    ZR_FILE_CONTENT_REQUEST(local->name)) {      
+			dict = get_new_dict ();
+			dict_set (dict, local->dict->members_list->key, 
+				  data_from_dynptr(NULL, 0));
+			dict_ref (dict);
+
+			local->call_count = 1;
+
+			STACK_WIND (frame,
+				    unify_setxattr_file_cbk,
+				    NS(this),
+				    NS(this)->fops->setxattr,
+				    &local->loc1,
+				    dict,
+				    XATTR_CREATE);
+
+			dict_unref (dict);
+			return 0;
+		}
+    
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_sexattr - This function should be sent to all the storage nodes, 
+ *       which contains the file, (excluding namespace).
+ */
+int32_t
+unify_setxattr (call_frame_t *frame,
+		xlator_t *this,
+		loc_t *loc,
+		dict_t *dict,
+		int32_t flags)
+{
+	unify_private_t *priv = this->private;
+	unify_local_t *local = NULL;
+	int16_t *list = NULL;
+	int16_t index = 0;
+	int32_t call_count = 0;
+  	uint64_t tmp_list = 0;
+	data_pair_t *trav = dict->members_list;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->failed = -1;
+	loc_copy (&local->loc1, loc);
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+
+		if (trav && trav->key && ZR_FILE_CONTENT_REQUEST(trav->key)) {
+			/* direct the storage xlators to change file 
+			   content only if file exists */
+			local->flags = flags;
+			local->dict = dict;
+			local->name = strdup (trav->key);
+			flags |= XATTR_REPLACE;
+		}
+
+		local->call_count = priv->child_count;
+		for (index = 0; index < priv->child_count; index++) {
+			STACK_WIND (frame,
+				    unify_setxattr_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->setxattr,
+				    loc, dict, flags);
+		}
+		return 0;
+	}
+
+	inode_ctx_get (loc->inode, this, &tmp_list);
+	list = (int16_t *)(long)tmp_list;
+
+	for (index = 0; list[index] != -1; index++) {
+		if (NS(this) != priv->xl_array[list[index]]) {
+			local->call_count++;
+			call_count++;
+		}
+	}
+  
+	if (local->call_count) {
+		for (index = 0; list[index] != -1; index++) {
+			if (priv->xl_array[list[index]] != NS(this)) {
+				STACK_WIND (frame,
+					    unify_setxattr_cbk,
+					    priv->xl_array[list[index]],
+					    priv->xl_array[list[index]]->fops->setxattr,
+					    loc,
+					    dict,
+					    flags);
+				if (!--call_count)
+					break;
+			}
+		}
+		return 0;
+	}
+
+	/* No entry in storage nodes */
+	gf_log (this->name, GF_LOG_DEBUG, 
+		"returning ENOENT, file not found on storage node.");
+	STACK_UNWIND (frame, -1, ENOENT);
+
+	return 0;
+}
+
+
+/**
+ * unify_getxattr_cbk - This function is called from only one child, so, no
+ *     need of any lock or anything else, just send it to above layer 
+ */
+int32_t
+unify_getxattr_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    dict_t *value)
+{
+	int32_t callcnt = 0;
+	dict_t *local_value = NULL;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+  
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+    
+		if (op_ret == -1) {
+			local->op_errno = op_errno;
+			gf_log (this->name, 
+				(((op_errno == ENOENT) || 
+				  (op_errno == ENODATA) || 
+				  (op_errno == ENOTSUP)) ? 
+				 GF_LOG_DEBUG : GF_LOG_ERROR), 
+				"child(%s): path(%s): %s", 
+				prev_frame->this->name, 
+				(local->loc1.path)?local->loc1.path:"", 
+				strerror (op_errno));
+		} else {
+			if (!local->dict)
+				local->dict = dict_ref (value);
+			local->op_ret = op_ret;
+		}
+	}
+	UNLOCK (&frame->lock);
+  
+	if (!callcnt) {
+		local_value = local->dict;
+		local->dict = NULL;
+      
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      local_value);
+      
+		if (local_value)
+			dict_unref (local_value);
+	} 
+
+	return 0;
+}
+
+
+/** 
+ * unify_getxattr - This FOP is sent to only the storage node.
+ */
+int32_t
+unify_getxattr (call_frame_t *frame,
+		xlator_t *this,
+		loc_t *loc,
+		const char *name)
+{
+	unify_private_t *priv = this->private;
+	int16_t *list = NULL;
+	int16_t index = 0;
+	int16_t count = 0;
+	unify_local_t *local = NULL;
+  	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+	INIT_LOCAL (frame, local);
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+		local->call_count = priv->child_count;
+		for (index = 0; index < priv->child_count; index++)
+			STACK_WIND (frame,
+				    unify_getxattr_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->getxattr,
+				    loc,
+				    name);
+		return 0;
+	}
+
+	inode_ctx_get (loc->inode, this, &tmp_list);
+	list = (int16_t *)(long)tmp_list;
+
+	for (index = 0; list[index] != -1; index++) {
+		if (NS(this) != priv->xl_array[list[index]]) {
+			local->call_count++;
+			count++;
+		}
+	}
+
+	if (count) {
+		for (index = 0; list[index] != -1; index++) {
+			if (priv->xl_array[list[index]] != NS(this)) {
+				STACK_WIND (frame,
+					    unify_getxattr_cbk,
+					    priv->xl_array[list[index]],
+					    priv->xl_array[list[index]]->fops->getxattr,
+					    loc,
+					    name);
+				if (!--count)
+					break;
+			}
+		}
+	} else {
+		dict_t *tmp_dict = get_new_dict ();
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"%s: returning ENODATA, no file found on storage node",
+			loc->path);
+		STACK_UNWIND (frame, -1, ENODATA, tmp_dict);
+		dict_destroy (tmp_dict);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_removexattr_cbk - Wait till all the child node returns the call
+ *      and then UNWIND to above layer.
+ */
+int32_t
+unify_removexattr_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno)
+{
+	int32_t callcnt = 0;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+
+	LOCK (&frame->lock);
+	{ 
+		callcnt = --local->call_count;
+		if (op_ret == -1) {
+			local->op_errno = op_errno;
+			if (op_errno != ENOTSUP)
+				gf_log (this->name, GF_LOG_ERROR, 
+					"child(%s): path(%s): %s", 
+					prev_frame->this->name, 
+					local->loc1.path, strerror (op_errno));
+		} else {
+			local->op_ret = op_ret;
+		}
+	}
+	UNLOCK (&frame->lock);  
+
+	if (!callcnt) {
+		STACK_UNWIND (frame, local->op_ret, local->op_errno);
+	}
+
+	return 0;
+}
+
+/**
+ * unify_removexattr - Send it to all the child nodes which has the files.
+ */
+int32_t
+unify_removexattr (call_frame_t *frame,
+		   xlator_t *this,
+		   loc_t *loc,
+		   const char *name)
+{
+	unify_private_t *priv = this->private;
+	unify_local_t *local = NULL;
+	int16_t *list = NULL;
+	int16_t index = 0;
+	int32_t call_count = 0;
+  	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (loc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+
+	if (S_ISDIR (loc->inode->st_mode)) {
+		local->call_count = priv->child_count;
+		for (index = 0; index < priv->child_count; index++)
+			STACK_WIND (frame, 		    
+				    unify_removexattr_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->removexattr,
+				    loc,
+				    name);
+
+		return 0;
+	}
+
+	inode_ctx_get (loc->inode, this, &tmp_list);
+	list = (int16_t *)(long)tmp_list;
+
+	for (index = 0; list[index] != -1; index++) {
+		if (NS(this) != priv->xl_array[list[index]]) {
+			local->call_count++;
+			call_count++;
+		}
+	}
+
+	if (local->call_count) {
+		for (index = 0; list[index] != -1; index++) {
+			if (priv->xl_array[list[index]] != NS(this)) {
+				STACK_WIND (frame,
+					    unify_removexattr_cbk,
+					    priv->xl_array[list[index]],
+					    priv->xl_array[list[index]]->fops->removexattr,
+					    loc,
+					    name);
+				if (!--call_count)
+					break;
+			}
+		}
+		return 0;
+	} 
+
+	gf_log (this->name, GF_LOG_DEBUG, 
+		"%s: returning ENOENT, not found on storage node.", loc->path);
+	STACK_UNWIND (frame, -1, ENOENT);
+
+	return 0;
+}
+
+
+int32_t 
+unify_mknod_unlink_cbk (call_frame_t *frame,
+			void *cookie,
+			xlator_t *this,
+			int32_t op_ret,
+			int32_t op_errno)
+{
+	unify_local_t *local = frame->local;
+
+	if (op_ret == -1)
+		gf_log (this->name, GF_LOG_ERROR, 
+			"%s: %s", local->loc1.path, strerror (op_errno));
+  
+	unify_local_wipe (local);
+	/* No log required here as this -1 is for mknod call */
+	STACK_UNWIND (frame, -1, local->op_errno, NULL, NULL);
+	return 0;
+}
+
+/**
+ * unify_mknod_cbk - 
+ */
+int32_t
+unify_mknod_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 inode_t *inode,
+		 struct stat *buf)
+{
+	unify_local_t *local = frame->local;
+
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"mknod failed on storage node, sending unlink to "
+			"namespace");
+		local->op_errno = op_errno;
+		STACK_WIND (frame,
+			    unify_mknod_unlink_cbk,
+			    NS(this),
+			    NS(this)->fops->unlink,
+			    &local->loc1);
+		return 0;
+	}
+  
+	local->stbuf = *buf;
+	local->stbuf.st_ino = local->st_ino;
+	unify_local_wipe (local);
+	STACK_UNWIND (frame, op_ret, op_errno, inode, &local->stbuf);
+	return 0;
+}
+
+/**
+ * unify_ns_mknod_cbk - 
+ */
+int32_t
+unify_ns_mknod_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    inode_t *inode,
+		    struct stat *buf)
+{
+	struct sched_ops *sched_ops = NULL;
+	xlator_t *sched_xl = NULL;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int16_t *list = NULL;
+	int16_t index = 0;
+	call_frame_t *prev_frame = cookie;
+
+	if (op_ret == -1) {
+		/* No need to send mknod request to other servers, 
+		 * as namespace action failed 
+		 */
+		gf_log (this->name, GF_LOG_ERROR, 
+			"child(%s): path(%s): %s", 
+			prev_frame->this->name, local->loc1.path, 
+			strerror (op_errno));
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno, inode, buf);
+		return 0;
+	}
+  
+	/* Create one inode for this entry */
+	local->op_ret = 0;
+	local->stbuf = *buf;
+	local->st_ino = buf->st_ino;
+
+	list = CALLOC (1, sizeof (int16_t) * 3);
+	ERR_ABORT (list);
+	list[0] = priv->child_count;
+	list[2] = -1;
+	inode_ctx_put (inode, this, (uint64_t)(long)list);
+
+	sched_ops = priv->sched_ops;
+
+	/* Send mknod request to scheduled node now */
+	sched_xl = sched_ops->schedule (this, local->loc1.path); 
+	if (!sched_xl) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"mknod failed on storage node, no node online "
+			"at the moment, sending unlink to NS");
+		local->op_errno = ENOTCONN;
+		STACK_WIND (frame,
+			    unify_mknod_unlink_cbk,
+			    NS(this),
+			    NS(this)->fops->unlink,
+			    &local->loc1);
+      
+		return 0;
+	}
+
+	for (index = 0; index < priv->child_count; index++)
+		if (sched_xl == priv->xl_array[index])
+			break;
+	list[1] = index;
+  
+	STACK_WIND (frame,  unify_mknod_cbk,
+		    sched_xl,  sched_xl->fops->mknod,
+		    &local->loc1, local->mode, local->dev);
+
+	return 0;
+}
+
+/**
+ * unify_mknod - Create a device on namespace first, and later create on 
+ *       the storage node.
+ */
+int32_t
+unify_mknod (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     mode_t mode,
+	     dev_t rdev)
+{
+	unify_local_t *local = NULL;
+  
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	local->mode = mode;
+	local->dev = rdev;
+	loc_copy (&local->loc1, loc);
+	if (local->loc1.path == NULL) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, loc->inode, NULL);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    unify_ns_mknod_cbk,
+		    NS(this),
+		    NS(this)->fops->mknod,
+		    loc,
+		    mode,
+		    rdev);
+
+	return 0;
+}
+
+int32_t 
+unify_symlink_unlink_cbk (call_frame_t *frame,
+			  void *cookie,
+			  xlator_t *this,
+			  int32_t op_ret,
+			  int32_t op_errno)
+{
+	unify_local_t *local = frame->local;
+	if (op_ret == -1)
+		gf_log (this->name, GF_LOG_ERROR, 
+			"%s: %s", local->loc1.path, strerror (op_errno));
+
+	unify_local_wipe (local);
+	STACK_UNWIND (frame, -1, local->op_errno, NULL, NULL);
+	return 0;
+}
+
+/**
+ * unify_symlink_cbk - 
+ */
+int32_t
+unify_symlink_cbk (call_frame_t *frame,
+		   void *cookie,
+		   xlator_t *this,
+		   int32_t op_ret,
+		   int32_t op_errno,
+		   inode_t *inode,
+		   struct stat *buf)
+{
+	unify_local_t *local = frame->local;
+
+	if (op_ret == -1) {
+		/* Symlink on storage node failed, hence send unlink 
+		   to the NS node */
+		local->op_errno = op_errno;
+		gf_log (this->name, GF_LOG_ERROR, 
+			"symlink on storage node failed, sending unlink "
+			"to namespace");
+
+		STACK_WIND (frame,
+			    unify_symlink_unlink_cbk,
+			    NS(this),
+			    NS(this)->fops->unlink,
+			    &local->loc1);
+    
+		return 0;
+	}
+  
+	local->stbuf = *buf;
+	local->stbuf.st_ino = local->st_ino;
+	unify_local_wipe (local);
+	STACK_UNWIND (frame, op_ret, op_errno, inode, &local->stbuf);
+
+	return 0;
+}
+
+/**
+ * unify_ns_symlink_cbk - 
+ */
+int32_t
+unify_ns_symlink_cbk (call_frame_t *frame,
+		      void *cookie,
+		      xlator_t *this,
+		      int32_t op_ret,
+		      int32_t op_errno,
+		      inode_t *inode,
+		      struct stat *buf)
+{
+
+	struct sched_ops *sched_ops = NULL;
+	xlator_t *sched_xl = NULL;
+	int16_t *list = NULL;
+	unify_local_t *local = frame->local;
+	unify_private_t *priv = this->private;
+	int16_t index = 0;
+
+	if (op_ret == -1) {
+		/* No need to send symlink request to other servers, 
+		 * as namespace action failed 
+		 */
+		gf_log (this->name, GF_LOG_ERROR, 
+			"namespace: path(%s): %s", 
+			local->loc1.path, strerror (op_errno));
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno, NULL, buf);
+		return 0;
+	}
+  
+	/* Create one inode for this entry */
+	local->op_ret = 0;
+	local->st_ino = buf->st_ino;
+  
+	/* Start the mapping list */
+
+	list = CALLOC (1, sizeof (int16_t) * 3);
+	ERR_ABORT (list);
+	list[0] = priv->child_count; //namespace's index
+	list[2] = -1;
+	inode_ctx_put (inode, this, (uint64_t)(long)list);
+
+	sched_ops = priv->sched_ops;
+
+	/* Send symlink request to all the nodes now */
+	sched_xl = sched_ops->schedule (this, local->loc1.path); 
+	if (!sched_xl) {
+		/* Symlink on storage node failed, hence send unlink 
+		   to the NS node */
+		local->op_errno = ENOTCONN;
+		gf_log (this->name, GF_LOG_ERROR, 
+			"symlink on storage node failed, no node online, "
+			"sending unlink to namespace");
+      
+		STACK_WIND (frame,
+			    unify_symlink_unlink_cbk,
+			    NS(this),
+			    NS(this)->fops->unlink,
+			    &local->loc1);
+      
+		return 0;
+	}
+
+	for (index = 0; index < priv->child_count; index++)
+		if (sched_xl == priv->xl_array[index])
+			break;
+	list[1] = index;
+	
+	STACK_WIND (frame,
+		    unify_symlink_cbk,
+		    sched_xl,
+		    sched_xl->fops->symlink,
+		    local->name,
+		    &local->loc1);
+
+	return 0;
+}
+
+/**
+ * unify_symlink - 
+ */
+int32_t
+unify_symlink (call_frame_t *frame,
+	       xlator_t *this,
+	       const char *linkpath,
+	       loc_t *loc)
+{
+	unify_local_t *local = NULL;
+  
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, loc);
+	local->name = strdup (linkpath);
+
+	if ((local->name == NULL) || 
+	    (local->loc1.path == NULL)) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, loc->inode, NULL);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    unify_ns_symlink_cbk,
+		    NS(this),
+		    NS(this)->fops->symlink,
+		    linkpath,
+		    loc);
+
+	return 0;
+}
+
+
+int32_t 
+unify_rename_unlink_cbk (call_frame_t *frame,
+			 void *cookie,
+			 xlator_t *this,
+			 int32_t op_ret,
+			 int32_t op_errno)
+{
+	int32_t callcnt = 0;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+  
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"child(%s): path(%s -> %s): %s", 
+			prev_frame->this->name, 
+			local->loc1.path, local->loc2.path, 
+			strerror (op_errno));
+      
+	}
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		local->stbuf.st_ino = local->st_ino;
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      &local->stbuf);
+	}
+	return 0;
+}
+
+int32_t 
+unify_ns_rename_undo_cbk (call_frame_t *frame,
+			  void *cookie,
+			  xlator_t *this,
+			  int32_t op_ret,
+			  int32_t op_errno,
+			  struct stat *buf)
+{
+	unify_local_t *local = frame->local;
+
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"namespace: path(%s -> %s): %s", 
+			local->loc1.path, local->loc2.path, 
+			strerror (op_errno));
+	}
+
+	local->stbuf.st_ino = local->st_ino;
+	unify_local_wipe (local);
+	STACK_UNWIND (frame, local->op_ret, local->op_errno, &local->stbuf);
+	return 0;
+}
+
+int32_t 
+unify_rename_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno,
+		  struct stat *buf)
+{
+	int32_t index = 0;
+	int32_t callcnt = 0;
+	int16_t *list = NULL;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	call_frame_t *prev_frame = cookie;
+  
+	LOCK (&frame->lock);
+	{
+		callcnt = --local->call_count;
+		if (op_ret >= 0) {
+			if (!S_ISDIR (buf->st_mode))
+				local->stbuf = *buf;
+			local->op_ret = op_ret;
+		} else {
+			gf_log (this->name, GF_LOG_ERROR, 
+				"child(%s): path(%s -> %s): %s", 
+				prev_frame->this->name, 
+				local->loc1.path, local->loc2.path, 
+				strerror (op_errno));
+			local->op_errno = op_errno;
+		}
+	}
+	UNLOCK (&frame->lock);
+
+	if (!callcnt) {
+		local->stbuf.st_ino = local->st_ino;
+		if (S_ISDIR (local->loc1.inode->st_mode)) {
+			unify_local_wipe (local);
+			STACK_UNWIND (frame, local->op_ret, local->op_errno, &local->stbuf);
+			return 0;
+		}
+
+		if (local->op_ret == -1) {
+			/* TODO: check this logic */
+
+			/* Rename failed in storage node, successful on NS, 
+			 * hence, rename back the entries in NS */
+			/* NOTE: this will be done only if the destination 
+			 * doesn't exists, if  the destination exists, the 
+			 * job of correcting NS is left to self-heal
+			 */
+			if (!local->index) {
+				loc_t tmp_oldloc = {
+                                        /* its actual 'newloc->path' */
+					.path = local->loc2.path, 
+					.inode = local->loc1.inode,
+					.parent = local->loc2.parent
+				};
+	
+				loc_t tmp_newloc = {
+					/* Actual 'oldloc->path' */
+					.path = local->loc1.path,
+					.parent = local->loc1.parent
+				};
+
+				gf_log (this->name, GF_LOG_ERROR, 
+					"rename succussful on namespace, on "
+					"stroage node failed, reverting back");
+
+				STACK_WIND (frame,
+					    unify_ns_rename_undo_cbk,
+					    NS(this),
+					    NS(this)->fops->rename,
+					    &tmp_oldloc,
+					    &tmp_newloc);
+				return 0;
+			}
+		} else {
+			/* Rename successful on storage nodes */
+
+			int32_t idx = 0;
+			int16_t *tmp_list = NULL;
+			uint64_t tmp_list_int64 = 0;
+			if (local->loc2.inode) {
+				inode_ctx_get (local->loc2.inode, 
+					       this, &tmp_list_int64);
+				list = (int16_t *)(long)tmp_list_int64;
+
+			}
+
+			if (list) {				
+				for (index = 0; list[index] != -1; index++);
+				tmp_list = CALLOC (1, index * 2);
+				memcpy (tmp_list, list, index * 2);
+
+				for (index = 0; list[index] != -1; index++) {
+					/* TODO: Check this logic. */
+					/* If the destination file exists in 
+					 * the same storage node where we sent
+					 * 'rename' call, no need to send 
+					 * unlink 
+					 */
+					for (idx = 0; 
+					     local->list[idx] != -1; idx++) {
+						if (tmp_list[index] == local->list[idx]) {
+							tmp_list[index] = priv->child_count;
+							continue;
+						}
+					}
+	  
+					if (NS(this) != priv->xl_array[tmp_list[index]]) {
+						local->call_count++;
+						callcnt++;
+					}
+				}
+
+				if (local->call_count) {
+					if (callcnt > 1)
+						gf_log (this->name, 
+							GF_LOG_ERROR, 
+							"%s->%s: more (%d) "
+							"subvolumes have the "
+							"newloc entry", 
+							local->loc1.path, 
+							local->loc2.path, 
+							callcnt);
+
+					for (index=0; 
+					     tmp_list[index] != -1; index++) {
+						if (NS(this) != priv->xl_array[tmp_list[index]]) {		    
+							STACK_WIND (frame,
+								    unify_rename_unlink_cbk,
+								    priv->xl_array[tmp_list[index]],
+								    priv->xl_array[tmp_list[index]]->fops->unlink,
+								    &local->loc2);
+							if (!--callcnt)
+								break;
+						}
+					}
+
+					FREE (tmp_list);
+					return 0;
+				}
+				if (tmp_list)
+					FREE (tmp_list);
+			}
+		}
+    
+		/* Need not send 'unlink' to storage node */
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, local->op_ret, 
+			      local->op_errno, &local->stbuf);
+	}
+
+	return 0;
+}
+
+int32_t 
+unify_ns_rename_cbk (call_frame_t *frame,
+		     void *cookie,
+		     xlator_t *this,
+		     int32_t op_ret,
+		     int32_t op_errno,
+		     struct stat *buf)
+{
+	int32_t index = 0;
+	int32_t callcnt = 0;
+	int16_t *list = NULL;
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+
+	if (op_ret == -1) {
+		/* Free local->new_inode */
+		gf_log (this->name, GF_LOG_ERROR, 
+			"namespace: path(%s -> %s): %s", 
+			local->loc1.path, local->loc2.path, 
+			strerror (op_errno));
+
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno, buf);
+		return 0;
+	}
+
+	local->stbuf = *buf;
+	local->st_ino = buf->st_ino;
+
+	/* Everything is fine. */
+	if (S_ISDIR (buf->st_mode)) {
+		local->call_count = priv->child_count;
+		for (index=0; index < priv->child_count; index++) {
+			STACK_WIND (frame,
+				    unify_rename_cbk,
+				    priv->xl_array[index],
+				    priv->xl_array[index]->fops->rename,
+				    &local->loc1,
+				    &local->loc2);
+		}
+
+		return 0;
+	}
+
+	local->call_count = 0;  
+	/* send rename */
+	list = local->list;
+	for (index=0; list[index] != -1; index++) {
+		if (NS(this) != priv->xl_array[list[index]]) {
+			local->call_count++;
+			callcnt++;
+		}
+	}
+
+	if (local->call_count) {
+		for (index=0; list[index] != -1; index++) {
+			if (NS(this) != priv->xl_array[list[index]]) {
+				STACK_WIND (frame,
+					    unify_rename_cbk,
+					    priv->xl_array[list[index]],
+					    priv->xl_array[list[index]]->fops->rename,
+					    &local->loc1,
+					    &local->loc2);
+				if (!--callcnt)
+					break;
+			}
+		}
+	} else {
+		/* file doesn't seem to be present in storage nodes */
+		gf_log (this->name, GF_LOG_CRITICAL,
+			"CRITICAL: source file not in storage node, "
+			"rename successful on namespace :O");
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, -1, EIO, NULL);
+	}
+	return 0;
+}
+
+
+/**
+ * unify_rename - One of the tricky function. The deadliest of all :O
+ */
+int32_t
+unify_rename (call_frame_t *frame,
+	      xlator_t *this,
+	      loc_t *oldloc,
+	      loc_t *newloc)
+{
+	unify_local_t *local = NULL;
+  	uint64_t tmp_list = 0;
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+	loc_copy (&local->loc1, oldloc);
+	loc_copy (&local->loc2, newloc);
+
+	if ((local->loc1.path == NULL) || 
+	    (local->loc2.path == NULL)) {
+		gf_log (this->name, GF_LOG_CRITICAL, "Not enough memory :O");
+		STACK_UNWIND (frame, -1, ENOMEM, NULL);
+		return 0;
+	}
+  
+	inode_ctx_get (oldloc->inode, this, &tmp_list);
+	local->list = (int16_t *)(long)tmp_list;
+
+	STACK_WIND (frame,
+		    unify_ns_rename_cbk,
+		    NS(this),
+		    NS(this)->fops->rename,
+		    oldloc,
+		    newloc);
+	return 0;
+}
+
+/**
+ * unify_link_cbk -
+ */
+int32_t
+unify_link_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		inode_t *inode,
+		struct stat *buf)
+{
+	unify_local_t *local = frame->local;
+
+	if (op_ret >= 0) 
+		local->stbuf = *buf;
+	local->stbuf.st_ino = local->st_ino;
+
+	unify_local_wipe (local);
+	STACK_UNWIND (frame, op_ret, op_errno, inode, &local->stbuf);
+
+	return 0;
+}
+
+/**
+ * unify_ns_link_cbk - 
+ */
+int32_t
+unify_ns_link_cbk (call_frame_t *frame,
+		   void *cookie,
+		   xlator_t *this,
+		   int32_t op_ret,
+		   int32_t op_errno,
+		   inode_t *inode,
+		   struct stat *buf)
+{
+	unify_private_t *priv = this->private;
+	unify_local_t *local = frame->local;
+	int16_t *list = local->list;
+	int16_t index = 0;
+
+	if (op_ret == -1) {
+		/* No need to send link request to other servers, 
+		 * as namespace action failed 
+		 */
+		gf_log (this->name, GF_LOG_ERROR, 
+			"namespace: path(%s -> %s): %s", 
+			local->loc1.path, local->loc2.path, 
+			strerror (op_errno));
+		unify_local_wipe (local);
+		STACK_UNWIND (frame, op_ret, op_errno, inode, buf);
+		return 0;
+	}
+
+	/* Update inode for this entry */
+	local->op_ret = 0;
+	local->st_ino = buf->st_ino;
+
+	/* Send link request to the node now */
+	for (index = 0; list[index] != -1; index++) {
+		char need_break = (list[index+1] == -1);
+		if (priv->xl_array[list[index]] != NS (this)) {
+			STACK_WIND (frame,
+				    unify_link_cbk,
+				    priv->xl_array[list[index]],
+				    priv->xl_array[list[index]]->fops->link,
+				    &local->loc1,
+				    &local->loc2);
+		}
+		if (need_break)
+			break;
+	}
+
+	return 0;
+}
+
+/**
+ * unify_link - 
+ */
+int32_t
+unify_link (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *oldloc,
+	    loc_t *newloc)
+{
+	unify_local_t *local = NULL;
+  	uint64_t tmp_list = 0;
+
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (oldloc);
+	UNIFY_CHECK_INODE_CTX_AND_UNWIND_ON_ERR (newloc);
+
+	/* Initialization */
+	INIT_LOCAL (frame, local);
+
+	loc_copy (&local->loc1, oldloc);
+	loc_copy (&local->loc2, newloc);
+
+	inode_ctx_get (oldloc->inode, this, &tmp_list);
+	local->list = (int16_t *)(long)tmp_list;
+
+	STACK_WIND (frame,
+		    unify_ns_link_cbk,
+		    NS(this),
+		    NS(this)->fops->link,
+		    oldloc,
+		    newloc);
+
+	return 0;
+}
+
+
+/**
+ * unify_checksum_cbk - 
+ */
+int32_t
+unify_checksum_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno,
+		    uint8_t *fchecksum,
+		    uint8_t *dchecksum)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, fchecksum, dchecksum);
+
+	return 0;
+}
+
+/**
+ * unify_checksum - 
+ */
+int32_t
+unify_checksum (call_frame_t *frame,
+		xlator_t *this,
+		loc_t *loc,
+		int32_t flag)
+{
+	STACK_WIND (frame,
+		    unify_checksum_cbk,
+		    NS(this),
+		    NS(this)->fops->checksum,
+		    loc,
+		    flag);
+
+	return 0;
+}
+
+
+/**
+ * unify_finodelk_cbk - 
+ */
+int
+unify_finodelk_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+		    int32_t op_ret, int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+/**
+ * unify_finodelk
+ */
+int
+unify_finodelk (call_frame_t *frame, xlator_t *this,
+		fd_t *fd, int cmd, struct flock *flock)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame, unify_finodelk_cbk,
+		    child, child->fops->finodelk,
+		    fd, cmd, flock);
+
+	return 0;
+}
+
+
+
+/**
+ * unify_fentrylk_cbk - 
+ */
+int
+unify_fentrylk_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+		    int32_t op_ret, int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+/**
+ * unify_fentrylk
+ */
+int
+unify_fentrylk (call_frame_t *frame, xlator_t *this,
+		fd_t *fd, const char *basename,
+		entrylk_cmd cmd, entrylk_type type)
+		
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame, unify_fentrylk_cbk,
+		    child, child->fops->fentrylk,
+		    fd, basename, cmd, type);
+
+	return 0;
+}
+
+
+
+/**
+ * unify_fxattrop_cbk - 
+ */
+int
+unify_fxattrop_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+		    int32_t op_ret, int32_t op_errno, dict_t *xattr)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, xattr);
+	return 0;
+}
+
+/**
+ * unify_fxattrop
+ */
+int
+unify_fxattrop (call_frame_t *frame, xlator_t *this,
+		fd_t *fd, gf_xattrop_flags_t optype, dict_t *xattr)
+{
+	UNIFY_CHECK_FD_CTX_AND_UNWIND_ON_ERR (fd);
+	xlator_t *child = NULL;
+	uint64_t tmp_child = 0;
+
+	fd_ctx_get (fd, this, &tmp_child);
+	child = (xlator_t *)(long)tmp_child;		     
+
+	STACK_WIND (frame, unify_fxattrop_cbk,
+		    child, child->fops->fxattrop,
+		    fd, optype, xattr);
+
+	return 0;
+}
+
+
+/**
+ * unify_inodelk_cbk - 
+ */
+int
+unify_inodelk_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+		   int32_t op_ret, int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+
+/**
+ * unify_inodelk
+ */
+int
+unify_inodelk (call_frame_t *frame, xlator_t *this,
+	       loc_t *loc, int cmd, struct flock *flock)
+{
+	xlator_t *child = NULL;
+
+	child = unify_loc_subvol (loc, this);
+
+	STACK_WIND (frame, unify_inodelk_cbk,
+		    child, child->fops->inodelk,
+		    loc, cmd, flock);
+
+	return 0;
+}
+
+
+
+/**
+ * unify_entrylk_cbk - 
+ */
+int
+unify_entrylk_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+		   int32_t op_ret, int32_t op_errno)
+{
+	STACK_UNWIND (frame, op_ret, op_errno);
+	return 0;
+}
+
+/**
+ * unify_entrylk
+ */
+int
+unify_entrylk (call_frame_t *frame, xlator_t *this,
+	       loc_t *loc, const char *basename,
+	       entrylk_cmd cmd, entrylk_type type)
+		
+{
+	xlator_t *child = NULL;
+
+	child = unify_loc_subvol (loc, this);
+
+	STACK_WIND (frame, unify_entrylk_cbk,
+		    child, child->fops->entrylk,
+		    loc, basename, cmd, type);
+
+	return 0;
+}
+
+
+
+/**
+ * unify_xattrop_cbk - 
+ */
+int
+unify_xattrop_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+		   int32_t op_ret, int32_t op_errno, dict_t *xattr)
+{
+	STACK_UNWIND (frame, op_ret, op_errno, xattr);
+	return 0;
+}
+
+/**
+ * unify_xattrop
+ */
+int
+unify_xattrop (call_frame_t *frame, xlator_t *this,
+		loc_t *loc, gf_xattrop_flags_t optype, dict_t *xattr)
+{
+	xlator_t *child = NULL;
+
+	child = unify_loc_subvol (loc, this);
+
+	STACK_WIND (frame, unify_xattrop_cbk,
+		    child, child->fops->xattrop,
+		    loc, optype, xattr);
+
+	return 0;
+}
+
+
+/**
+ * notify
+ */
+int32_t
+notify (xlator_t *this,
+        int32_t event,
+        void *data,
+        ...)
+{
+	unify_private_t *priv = this->private;
+	struct sched_ops *sched = NULL;
+
+	if (!priv) {
+		return 0;
+	}
+
+	sched = priv->sched_ops;    
+	if (!sched) {
+		gf_log (this->name, GF_LOG_CRITICAL, "No scheduler :O");
+		raise (SIGTERM);
+		return 0;
+	}
+	if (priv->namespace == data) {
+		if (event == GF_EVENT_CHILD_UP) {
+			sched->notify (this, event, data);
+		}
+		return 0;
+	}
+
+	switch (event)
+	{
+	case GF_EVENT_CHILD_UP:
+	{
+		/* Call scheduler's update () to enable it for scheduling */
+		sched->notify (this, event, data);
+	
+		LOCK (&priv->lock);
+		{
+			/* Increment the inode's generation, which is 
+			   used for self_heal */
+			++priv->inode_generation;
+			++priv->num_child_up;
+		}
+		UNLOCK (&priv->lock);
+
+		if (!priv->is_up) {
+			default_notify (this, event, data);
+			priv->is_up = 1;
+		}
+	}
+	break;
+	case GF_EVENT_CHILD_DOWN:
+	{
+		/* Call scheduler's update () to disable the child node 
+		 * for scheduling
+		 */
+		sched->notify (this, event, data);
+		LOCK (&priv->lock);
+		{
+			--priv->num_child_up;
+		}
+		UNLOCK (&priv->lock);
+
+		if (priv->num_child_up == 0) {
+			/* Send CHILD_DOWN to upper layer */
+			default_notify (this, event, data);
+			priv->is_up = 0;
+		}
+	}
+	break;
+
+	default:
+	{
+		default_notify (this, event, data);
+	}
+	break;
+	}
+
+	return 0;
+}
+
+/** 
+ * init - This function is called first in the xlator, while initializing.
+ *   All the config file options are checked and appropriate flags are set.
+ *
+ * @this - 
+ */
+int32_t 
+init (xlator_t *this)
+{
+	int32_t          ret       = 0;
+	int32_t          count     = 0;
+	data_t          *scheduler = NULL;
+	data_t          *data      = NULL;
+	xlator_t        *ns_xl     = NULL;
+	xlator_list_t   *trav      = NULL;
+	xlator_list_t   *xlparent  = NULL;
+	xlator_list_t   *parent    = NULL;
+	unify_private_t *_private  = NULL; 
+
+	/* Check for number of child nodes, if there is no child nodes, exit */
+	if (!this->children) {
+		gf_log (this->name, GF_LOG_ERROR,
+			"No child nodes specified. check \"subvolumes \" "
+			"option in volfile");
+		return -1;
+	}
+
+  	if (!this->parents) {
+		gf_log (this->name, GF_LOG_WARNING,
+			"dangling volume. check volfile ");
+	}
+  
+	/* Check for 'scheduler' in volume */
+	scheduler = dict_get (this->options, "scheduler");
+	if (!scheduler) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"\"option scheduler <x>\" is missing in volfile");
+		return -1;
+	}
+
+	/* Setting "option namespace <node>" */
+	data = dict_get (this->options, "namespace");
+	if(!data) {
+		gf_log (this->name, GF_LOG_CRITICAL, 
+			"namespace option not specified, Exiting");
+		return -1;
+	}
+	/* Search namespace in the child node, if found, exit */
+	trav = this->children;
+	while (trav) {
+		if (strcmp (trav->xlator->name, data->data) == 0)
+			break;
+		trav = trav->next;
+	}
+	if (trav) {
+		gf_log (this->name, GF_LOG_CRITICAL, 
+			"namespace node used as a subvolume, Exiting");
+		return -1;
+	}
+	
+	/* Search for the namespace node, if found, continue */
+	ns_xl = this->next;
+	while (ns_xl) {
+		if (strcmp (ns_xl->name, data->data) == 0)
+			break;
+		ns_xl = ns_xl->next;
+	}
+	if (!ns_xl) {
+		gf_log (this->name, GF_LOG_CRITICAL, 
+			"namespace node not found in volfile, Exiting");
+		return -1;
+	}
+	
+	gf_log (this->name, GF_LOG_DEBUG, 
+		"namespace node specified as %s", data->data);
+	
+	_private = CALLOC (1, sizeof (*_private));
+	ERR_ABORT (_private);
+	_private->sched_ops = get_scheduler (this, scheduler->data);
+	if (!_private->sched_ops) {
+		gf_log (this->name, GF_LOG_CRITICAL, 
+			"Error while loading scheduler. Exiting");
+		FREE (_private);
+		return -1;
+	}
+	
+	if (ns_xl->parents) {
+		gf_log (this->name, GF_LOG_CRITICAL,
+			"Namespace node should not be a child of any other node. Exiting");
+		FREE (_private);
+		return -1;
+	}
+
+	_private->namespace = ns_xl;
+	
+	/* update _private structure */
+	{
+		count = 0;
+		trav = this->children;
+		/* Get the number of child count */
+		while (trav) {
+			count++;
+			trav = trav->next;
+		}
+		
+		gf_log (this->name, GF_LOG_DEBUG, 
+			"Child node count is %d", count);    
+
+		_private->child_count = count;
+		if (count == 1) {
+			/* TODO: Should I error out here? */
+			gf_log (this->name, GF_LOG_CRITICAL, 
+				"WARNING: You have defined only one "
+				"\"subvolumes\" for unify volume. It may not "
+				"be the desired config, review your volume "
+				"volfile. If this is how you are testing it,"
+				" you may hit some performance penalty");
+		}
+		
+		_private->xl_array = CALLOC (1, 
+					     sizeof (xlator_t) * (count + 1));
+		ERR_ABORT (_private->xl_array);
+		
+		count = 0;
+		trav = this->children;
+		while (trav) {
+			_private->xl_array[count++] = trav->xlator;
+			trav = trav->next;
+		}
+		_private->xl_array[count] = _private->namespace;
+		
+		/* self-heal part, start with generation '1' */
+		_private->inode_generation = 1; 
+                /* Because, Foreground part is tested well */
+		_private->self_heal = ZR_UNIFY_FG_SELF_HEAL; 
+		data = dict_get (this->options, "self-heal");
+		if (data) {
+			if (strcasecmp (data->data, "off") == 0) 
+				_private->self_heal = ZR_UNIFY_SELF_HEAL_OFF;
+
+			if (strcasecmp (data->data, "foreground") == 0)
+				_private->self_heal = ZR_UNIFY_FG_SELF_HEAL;
+
+			if (strcasecmp (data->data, "background") == 0)
+				_private->self_heal = ZR_UNIFY_BG_SELF_HEAL;
+		}
+    
+		/* optimist - ask bulde for more about it */
+		data = dict_get (this->options, "optimist");
+		if (data) {
+			if (gf_string2boolean (data->data, 
+					       &_private->optimist) == -1) {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"optimist excepts only boolean "
+					"options");
+			}
+		}
+
+		LOCK_INIT (&_private->lock);
+	}
+
+	/* Now that everything is fine. */
+	this->private = (void *)_private;
+	{
+		/* Initialize scheduler, if everything else is successful */
+		ret = _private->sched_ops->init (this); 
+		if (ret == -1) {
+			gf_log (this->name, GF_LOG_CRITICAL,
+				"Initializing scheduler failed, Exiting");
+			FREE (_private);
+			return -1;
+		}
+
+		ret = 0;
+
+		/* This section is required because some fops may look 
+		 * for 'xl->parent' variable 
+		 */
+		xlparent = CALLOC (1, sizeof (*xlparent));
+		xlparent->xlator = this;
+		if (!ns_xl->parents) {
+			ns_xl->parents = xlparent;
+		} else {
+			parent = ns_xl->parents;
+			while (parent->next)
+				parent = parent->next;
+			parent->next = xlparent;
+		}
+		/* Initialize the namespace volume */
+		if (!ns_xl->ready) {
+			ret = xlator_tree_init (ns_xl);
+			if (ret) {
+				gf_log (this->name, GF_LOG_ERROR, 
+					"initializing namespace node failed, "
+					"Exiting");
+			FREE (_private);
+			return -1;
+			}
+		}
+	}
+
+	/* Tell namespace node that init is done */
+	ns_xl->notify (ns_xl, GF_EVENT_PARENT_UP, this);
+
+	return 0;
+}
+
+/** 
+ * fini  - Free all the allocated memory 
+ */
+void
+fini (xlator_t *this)
+{
+	unify_private_t *priv = this->private;
+	priv->sched_ops->fini (this);
+	this->private = NULL;
+	LOCK_DESTROY (&priv->lock);
+	FREE (priv->xl_array);
+	FREE (priv);
+	return;
+}
+
+
+struct xlator_fops fops = {
+	.stat        = unify_stat,
+	.chmod       = unify_chmod,
+	.readlink    = unify_readlink,
+	.mknod       = unify_mknod,
+	.mkdir       = unify_mkdir,
+	.unlink      = unify_unlink,
+	.rmdir       = unify_rmdir,
+	.symlink     = unify_symlink,
+	.rename      = unify_rename,
+	.link        = unify_link,
+	.chown       = unify_chown,
+	.truncate    = unify_truncate,
+	.create      = unify_create,
+	.open        = unify_open,
+	.readv       = unify_readv,
+	.writev      = unify_writev,
+	.statfs      = unify_statfs,
+	.flush       = unify_flush,
+	.fsync       = unify_fsync,
+	.setxattr    = unify_setxattr,
+	.getxattr    = unify_getxattr,
+	.removexattr = unify_removexattr,
+	.opendir     = unify_opendir,
+	.readdir     = unify_readdir,
+	.fsyncdir    = unify_fsyncdir,
+	.access      = unify_access,
+	.ftruncate   = unify_ftruncate,
+	.fstat       = unify_fstat,
+	.lk          = unify_lk,
+	.fchown      = unify_fchown,
+	.fchmod      = unify_fchmod,
+	.utimens     = unify_utimens,
+	.lookup      = unify_lookup,
+	.getdents    = unify_getdents,
+	.checksum    = unify_checksum,
+	.inodelk     = unify_inodelk,
+	.finodelk    = unify_finodelk,
+	.entrylk     = unify_entrylk,
+	.fentrylk    = unify_fentrylk,
+	.xattrop     = unify_xattrop,
+	.fxattrop    = unify_fxattrop
+};
+
+struct xlator_mops mops = {
+};
+
+struct xlator_cbks cbks = {
+};
+
+struct volume_options options[] = {
+	{ .key   = { "namespace" },  
+	  .type  = GF_OPTION_TYPE_XLATOR 
+	},
+	{ .key   = { "scheduler" },  
+	  .value = { "alu", "rr", "random", "nufa", "switch" },
+	  .type  = GF_OPTION_TYPE_STR
+	},
+	{ .key   = {"self-heal"},  
+	  .value = { "foreground", "background", "off" },
+	  .type  = GF_OPTION_TYPE_STR
+	},
+	/* TODO: remove it some time later */
+	{ .key   = {"optimist"},  
+	  .type  = GF_OPTION_TYPE_BOOL 
+	},
+
+	{ .key   = {NULL} },
+};
diff --git a/xlators/cluster/unify/src/unify.h b/xlators/cluster/unify/src/unify.h
new file mode 100644
index 00000000000..bc18dc53f52
--- /dev/null
+++ b/xlators/cluster/unify/src/unify.h
@@ -0,0 +1,132 @@
+/*
+  Copyright (c) 2006, 2007, 2008 Z RESEARCH, Inc. <http://www.zresearch.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#ifndef _UNIFY_H
+#define _UNIFY_H
+
+#include "scheduler.h"
+#include "list.h"
+
+#define MAX_DIR_ENTRY_STRING     (32 * 1024)
+
+#define ZR_UNIFY_SELF_HEAL_OFF 0
+#define ZR_UNIFY_FG_SELF_HEAL  1
+#define ZR_UNIFY_BG_SELF_HEAL  2
+
+/* Sometimes one should use completely random numbers.. its good :p */
+#define UNIFY_SELF_HEAL_GETDENTS_COUNT 1024
+
+#define NS(xl)          (((unify_private_t *)xl->private)->namespace)
+
+/* This is used to allocate memory for local structure */
+#define INIT_LOCAL(fr, loc)                   \
+do {                                          \
+  loc = CALLOC (1, sizeof (unify_local_t));   \
+  ERR_ABORT (loc);			      \
+  if (!loc) {                                 \
+    STACK_UNWIND (fr, -1, ENOMEM);            \
+    return 0;                                 \
+  }                                           \
+  fr->local = loc;                            \
+  loc->op_ret = -1;                           \
+  loc->op_errno = ENOENT;                     \
+} while (0)
+
+
+
+struct unify_private {
+	/* Update this structure depending on requirement */
+	void *scheduler;               /* THIS SHOULD BE THE FIRST VARIABLE, 
+					  if xlator is using scheduler */
+	struct sched_ops *sched_ops;   /* Scheduler options  */
+	xlator_t *namespace;           /* ptr to namespace xlator */
+	xlator_t **xl_array;
+	gf_boolean_t optimist;
+	int16_t child_count;
+	int16_t num_child_up;
+	uint8_t self_heal;
+	uint8_t is_up;
+	uint64_t inode_generation;
+	gf_lock_t lock;
+};
+typedef struct unify_private unify_private_t;
+
+struct unify_self_heal_struct {
+	uint8_t dir_checksum[ZR_FILENAME_MAX];
+	uint8_t ns_dir_checksum[ZR_FILENAME_MAX];
+	uint8_t file_checksum[ZR_FILENAME_MAX];
+	uint8_t ns_file_checksum[ZR_FILENAME_MAX];
+	off_t *offset_list;
+	int   *count_list;
+	dir_entry_t **entry_list;
+};
+
+
+struct _unify_local_t {
+	int32_t call_count;
+	int32_t op_ret;
+	int32_t op_errno;
+	mode_t mode;
+	off_t offset;
+	dev_t dev;
+	uid_t uid;
+	gid_t gid;
+	int32_t flags;
+	int32_t entry_count;
+	int32_t count;    // dir_entry_t count;
+	fd_t *fd;
+	struct stat stbuf;
+	struct statvfs statvfs_buf;
+	struct timespec tv[2];
+	char *name;
+	int32_t revalidate;
+
+	ino_t st_ino;
+	nlink_t st_nlink;
+  
+	dict_t *dict;
+
+	int16_t *list;
+	int16_t *new_list; /* Used only in case of rename */
+	int16_t index;
+
+	int32_t failed;
+	int32_t return_eio;  /* Used in case of different st-mode 
+				present for a given path */
+
+	uint64_t inode_generation; /* used to store the per directory 
+				    * inode_generation. Got from inode's ctx 
+				    * of directory inodes
+				    */
+
+	struct unify_self_heal_struct *sh_struct;
+	loc_t loc1, loc2;
+};
+typedef struct _unify_local_t unify_local_t;
+
+int32_t zr_unify_self_heal (call_frame_t *frame,
+			    xlator_t *this,
+			    unify_local_t *local);
+
+#endif /* _UNIFY_H */