Added all files

5 files changed, 3747 insertions, 0 deletions

diff --git a/xlators/cluster/ha/Makefile.am b/xlators/cluster/ha/Makefile.am
new file mode 100644
index 000000000..d471a3f92
--- /dev/null
+++ b/xlators/cluster/ha/Makefile.am
@@ -0,0 +1,3 @@
+SUBDIRS = src
+
+CLEANFILES = 
diff --git a/xlators/cluster/ha/src/Makefile.am b/xlators/cluster/ha/src/Makefile.am
new file mode 100644
index 000000000..069a0dcde
--- /dev/null
+++ b/xlators/cluster/ha/src/Makefile.am
@@ -0,0 +1,15 @@
+xlator_LTLIBRARIES = ha.la
+xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/cluster
+
+ha_la_LDFLAGS = -module -avoidversion 
+
+ha_la_SOURCES = ha-helpers.c ha.c
+ha_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+
+noinst_HEADERS = ha.h
+
+AM_CFLAGS = -fPIC -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -Wall -D$(GF_HOST_OS) \
+	    -I$(top_srcdir)/libglusterfs/src -shared -nostartfiles $(GF_CFLAGS)
+
+CLEANFILES = 
+
diff --git a/xlators/cluster/ha/src/ha-helpers.c b/xlators/cluster/ha/src/ha-helpers.c
new file mode 100644
index 000000000..8193caf27
--- /dev/null
+++ b/xlators/cluster/ha/src/ha-helpers.c
@@ -0,0 +1,191 @@
+/*
+  Copyright (c) 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/>.
+*/
+
+#include "xlator.h"
+#include "call-stub.h"
+#include "defaults.h"
+#include "dict.h"
+#include "compat-errno.h"
+#include "ha.h"
+
+int ha_alloc_init_fd (call_frame_t *frame, fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	int i = -1;
+	ha_private_t *pvt = NULL;
+	int child_count = 0;
+	int ret = -1;
+	hafd_t *hafdp = NULL;
+	xlator_t *this = NULL;
+	uint64_t tmp_hafdp = 0;
+
+	this = frame->this;
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+
+	if (local == NULL) {
+		ret = fd_ctx_get (fd, this, &tmp_hafdp);
+		if (ret < 0) {
+			goto out;
+		}
+		hafdp = (hafd_t *)(long)tmp_hafdp;
+		local = frame->local = CALLOC (1, sizeof (*local));
+		if (local == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		local->state = CALLOC (1, child_count);
+		if (local->state == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		/* take care of the preferred subvolume */
+		if (pvt->pref_subvol == -1)
+			local->active = hafdp->active;
+		else
+			local->active = pvt->pref_subvol;
+
+		LOCK (&hafdp->lock);
+		memcpy (local->state, hafdp->fdstate, child_count);
+		UNLOCK (&hafdp->lock);
+
+		/* in case the preferred subvolume is down */
+		if ((local->active != -1) && (local->state[local->active] == 0))
+			local->active = -1;
+
+		for (i = 0; i < child_count; i++) {
+			if (local->state[i]) {
+				if (local->active == -1)
+					local->active = i;
+				local->tries++;
+			}
+		}
+		if (local->active == -1) {
+			ret = -ENOTCONN;
+			goto out;
+		}
+		local->fd = fd_ref (fd);
+	}
+	ret = 0;
+out:
+	return ret;
+}
+
+int ha_handle_cbk (call_frame_t *frame, void *cookie, int op_ret, int op_errno) 
+{
+	xlator_t *xl = NULL;
+	ha_private_t *pvt = NULL;
+	xlator_t **children = NULL;
+	int prev_child = -1;
+	hafd_t *hafdp = NULL;
+	int ret = -1;
+	call_stub_t *stub = NULL;
+	ha_local_t *local = NULL;
+	uint64_t tmp_hafdp = 0;
+
+	xl = frame->this;
+	pvt = xl->private;
+	children = pvt->children;
+	prev_child = (long) cookie;
+	local = frame->local;
+
+	if (op_ret == -1) {
+		gf_log (xl->name, GF_LOG_ERROR ,"(child=%s) (op_ret=%d op_errno=%s)",
+			children[prev_child]->name, op_ret, strerror (op_errno));
+	}
+	if (op_ret == -1 && (op_errno == ENOTCONN)) {
+		ret = 0;
+		if (local->fd) {
+			ret = fd_ctx_get (local->fd, xl, &tmp_hafdp);
+		}
+		hafdp = (hafd_t *)(long)tmp_hafdp;		
+		if (ret == 0) {
+			if (local->fd) {
+				LOCK(&hafdp->lock);
+				hafdp->fdstate[prev_child] = 0;
+				UNLOCK(&hafdp->lock);
+			}
+			local->tries--;
+			if (local->tries != 0) {
+				while (1) {
+					local->active = (local->active + 1) % pvt->child_count;
+					if (local->state[local->active])
+						break;
+				}
+				stub = local->stub;
+				local->stub = NULL;
+				call_resume (stub);
+				return -1;
+			}
+		}
+	}
+	if (local->stub)
+		call_stub_destroy (local->stub);
+	if (local->fd) {
+		FREE (local->state);
+		fd_unref (local->fd);
+	}
+	return 0;
+}
+
+int ha_alloc_init_inode (call_frame_t *frame, inode_t *inode)
+{
+	int i = -1;
+	ha_private_t *pvt = NULL;
+	xlator_t *xl = NULL;
+	int ret = -1;
+	ha_local_t *local = NULL;
+	uint64_t tmp_state = 0;
+
+	xl = frame->this;
+	pvt = xl->private;
+	local = frame->local;
+
+	if (local == NULL) {
+		local = frame->local = CALLOC (1, sizeof (*local));
+		if (local == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		local->active = pvt->pref_subvol;
+		ret = inode_ctx_get (inode, xl, &tmp_state);
+		if (ret < 0) {
+			goto out;
+		}
+		local->state = (char *)(long)tmp_state;
+		if (local->active != -1 && local->state[local->active] == 0)
+			local->active = -1;
+		for (i = 0; i < pvt->child_count; i++) {
+			if (local->state[i]) {
+				if (local->active == -1)
+					local->active = i;
+				local->tries++;
+			}
+		}
+		if (local->active == -1) {
+			ret = -ENOTCONN;
+			goto out;
+		}
+	}
+	ret = 0;
+out:
+	return ret;
+}
diff --git a/xlators/cluster/ha/src/ha.c b/xlators/cluster/ha/src/ha.c
new file mode 100644
index 000000000..4542bdc7e
--- /dev/null
+++ b/xlators/cluster/ha/src/ha.c
@@ -0,0 +1,3479 @@
+/*
+  Copyright (c) 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/>.
+*/
+
+/* generate errors randomly, code is simple now, better alogorithm
+ * can be written to decide what error to be returned and when
+ */
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "xlator.h"
+#include "call-stub.h"
+#include "defaults.h"
+#include "dict.h"
+#include "compat-errno.h"
+#include "ha.h"
+
+/*
+ * TODO:
+ * - dbench fails if ha over server side afr
+ * - lock calls - lock on all subvols.
+ * - support preferred-subvolume option. code already there.
+ * - do not alloc the call-stub in case only one subvol is up.
+ */
+
+int
+ha_forget (xlator_t *this,
+	   inode_t *inode)
+{
+	uint64_t stateino = 0;
+	char *state = NULL;
+	if (!inode_ctx_del (inode, this, &stateino)) {
+		state =  ((char *)(long)stateino);
+		FREE (state);
+	}
+
+	return 0;
+
+}
+
+int32_t 
+ha_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int child_count = 0, i = 0, callcnt = 0;
+	char *state = NULL;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_state = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++) {
+		if (pvt->children[i] == prev_frame->this)
+			break;
+	}
+	if ((op_ret == -1) && (op_errno != ENOENT)) {
+		gf_log (this->name, GF_LOG_ERROR, "(child=%s) (op_ret=%d op_errno=%s)", 
+			  children[i]->name, op_ret, strerror (op_errno));
+	}
+	inode_ctx_get (local->inode, this, &tmp_state);
+	state = (char *)(long)tmp_state;
+
+	LOCK (&frame->lock);
+	if (local->revalidate == 1) {
+		if ((!op_ret) != state[i]) {
+			local->revalidate_error = 1;
+			gf_log (this->name, GF_LOG_DEBUG, "revalidate error on %s", 
+				pvt->children[i]->name);
+		}
+	} else {
+		if (op_ret == 0) {
+			state[i] = 1;
+		}
+	}
+	if (local->op_ret == -1 && op_ret == 0) {
+		local->op_ret = 0;
+		local->buf = *buf;
+		if (dict)
+			local->dict = dict_ref (dict);
+	}
+	if (op_ret == -1 && op_ret != ENOTCONN)
+		local->op_errno = op_errno;
+	callcnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (callcnt == 0) {
+		dict_t *ctx = local->dict;
+		inode_t *inode = local->inode;
+		if (local->revalidate_error == 1) {
+			local->op_ret = -1;
+			local->op_errno = EIO;
+			gf_log (this->name, GF_LOG_DEBUG, "revalidate error, returning EIO");
+		}
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      inode,
+			      &local->buf,
+			      ctx);
+		if (inode)
+			inode_unref (inode);
+		if (ctx)
+			dict_unref (ctx);
+	}
+	return 0;
+}
+
+int32_t
+ha_lookup (call_frame_t *frame,
+	   xlator_t *this,
+	   loc_t *loc,
+	   dict_t *xattr_req)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int child_count = 0, i = 0;
+	char *state = NULL;
+	xlator_t **children = NULL;
+	int ret = -1;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	children = pvt->children;
+
+	frame->local = local = CALLOC (1, sizeof (*local));
+	child_count = pvt->child_count;
+	local->inode = inode_ref (loc->inode);
+
+	ret = inode_ctx_get (loc->inode, this, NULL);
+	if (ret) {
+		state = CALLOC (1, child_count);
+		inode_ctx_put (loc->inode, this, (uint64_t)(long)state);
+	} else
+		local->revalidate = 1;
+
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->call_count = child_count;
+
+	for (i = 0; i < child_count; i++) {
+		STACK_WIND (frame,
+			    ha_lookup_cbk,
+			    children[i],
+			    children[i]->fops->lookup,
+			    loc,
+			    xattr_req);
+	}
+	return 0;
+}
+
+ int32_t
+ha_stat_cbk (call_frame_t *frame,
+	     void *cookie,
+	     xlator_t *this,
+	     int32_t op_ret,
+	     int32_t op_errno,
+	     struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_stat (call_frame_t *frame,
+	 xlator_t *this,
+	 loc_t *loc)
+{
+	ha_local_t *local = NULL;
+	int op_errno = ENOTCONN;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_stat_stub (frame, ha_stat, loc);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_stat_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->stat,
+			   loc);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;	
+}
+
+ int32_t
+ha_chmod_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno,
+	      struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_chmod (call_frame_t *frame,
+	  xlator_t *this,
+	  loc_t *loc,
+	  mode_t mode)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_chmod_stub (frame, ha_chmod, loc, mode);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_chmod_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->chmod,
+			   loc,
+			   mode);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+ int32_t
+ha_fchmod_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno,
+	       struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t 
+ha_fchmod (call_frame_t *frame,
+	   xlator_t *this,
+	   fd_t *fd,
+	   mode_t mode)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_fchmod_stub (frame, ha_fchmod, fd, mode);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_fchmod_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->fchmod,
+			   fd,
+			   mode);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+ int32_t
+ha_chown_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno,
+	      struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_chown (call_frame_t *frame,
+	  xlator_t *this,
+	  loc_t *loc,
+	  uid_t uid,
+	  gid_t gid)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_chown_stub (frame, ha_chown, loc, uid, gid);
+
+	STACK_WIND_COOKIE (frame,	      
+			   ha_chown_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->chown,
+			   loc,
+			   uid,
+			   gid);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+	return 0;
+}
+
+ int32_t
+ha_fchown_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno,
+	       struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t 
+ha_fchown (call_frame_t *frame,
+	   xlator_t *this,
+	   fd_t *fd,
+	   uid_t uid,
+	   gid_t gid)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_fchown_stub (frame, ha_fchown, fd, uid, gid);
+
+	STACK_WIND_COOKIE (frame,	      
+			   ha_fchown_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->fchown,
+			   fd,
+			   uid,
+			   gid);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+ int32_t
+ha_truncate_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_truncate (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     off_t offset)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_truncate_stub (frame, ha_truncate, loc, offset);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_truncate_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->truncate,
+			   loc,
+			   offset);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+ int32_t
+ha_ftruncate_cbk (call_frame_t *frame,
+		  void *cookie,
+		  xlator_t *this,
+		  int32_t op_ret,
+		  int32_t op_errno,
+		  struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_ftruncate (call_frame_t *frame,
+	      xlator_t *this,
+	      fd_t *fd,
+	      off_t offset)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_ftruncate_stub (frame, ha_ftruncate, fd, offset);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_ftruncate_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->ftruncate,
+			   fd,
+			   offset);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+int32_t 
+ha_utimens_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t 
+ha_utimens (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc,
+	    struct timespec tv[2])
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_utimens_stub (frame, ha_utimens, loc, tv);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_utimens_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->utimens,
+			   loc,
+			   tv);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+int32_t
+ha_access_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_access (call_frame_t *frame,
+	   xlator_t *this,
+	   loc_t *loc,
+	   int32_t mask)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_access_stub (frame, ha_access, loc, mask);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_access_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->access,
+			   loc,
+			   mask);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+
+ int32_t
+ha_readlink_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 const char *path)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      path);
+	}
+	return 0;
+}
+
+int32_t
+ha_readlink (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     size_t size)
+{
+	ha_local_t *local = frame->local;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_readlink_stub (frame, ha_readlink, loc, size);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_readlink_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->readlink,
+			   loc,
+			   size);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+int
+ha_mknod_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0, ret = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"(path=%s) (op_ret=%d op_errno=%d)", 
+			local->stub->args.mknod.loc.path, op_ret, op_errno);
+	}
+	ret = inode_ctx_get (local->stub->args.mknod.loc.inode, 
+			     this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"unwind(-1), inode_ctx_get() error");
+		/* It is difficult to handle this error at this stage
+		 * as we still expect more cbks, we can't return as
+		 * of now
+		 */
+	} else if (op_ret == 0) {
+		stateino[i] = 1;
+	}
+	LOCK (&frame->lock);
+	cnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (cnt == 0) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      local->stub->args.mknod.loc.inode,
+			      &local->buf);
+		call_stub_destroy (stub);
+	}
+	return 0;
+}
+
+int32_t
+ha_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0, ret = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		local->op_errno = op_errno;
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.mknod.loc.path, op_ret, op_errno);
+	}
+
+	ret = inode_ctx_get (local->stub->args.mknod.loc.inode, 
+			     this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "inode_ctx_get() error");
+		/* FIXME: handle the case */
+	}
+	if (op_ret == 0) {
+		stateino[i] = 1;
+		local->op_ret = 0;
+		local->first_success = 1;
+		local->buf = *buf;
+	}
+	cnt = --local->call_count;
+	for (i = local->active + 1; i < child_count; i++) {
+		if (local->state[i])
+			break;
+	}
+
+	if (cnt == 0 || i == child_count) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		stub = local->stub;
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, local->stub->args.mknod.loc.inode, &local->buf);
+		call_stub_destroy (stub);
+		return 0;
+	}
+
+	local->active = i;
+
+	if (local->first_success == 0) {
+		STACK_WIND (frame,
+			    ha_mknod_cbk,
+			    children[i],
+			    children[i]->fops->mknod,
+			    &local->stub->args.mknod.loc,
+			    local->stub->args.mknod.mode,
+			    local->stub->args.mknod.rdev);
+		return 0;
+	}
+	cnt = local->call_count;
+
+	for (; i < child_count; i++) {
+		if (local->state[i]) {
+			STACK_WIND (frame,
+				    ha_mknod_lookup_cbk,
+				    children[i],
+				    children[i]->fops->lookup,
+				    &local->stub->args.mknod.loc,
+				    0);
+			if (--cnt == 0)
+				break;
+		}
+	}
+	return 0;
+}
+
+int32_t
+ha_mknod (call_frame_t *frame,
+	  xlator_t *this,
+	  loc_t *loc,
+	  mode_t mode,
+	  dev_t rdev)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int child_count = 0, i = 0;
+	char *stateino = NULL;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+
+	frame->local = local = CALLOC (1, sizeof (*local));
+	local->stub = fop_mknod_stub (frame, ha_mknod, loc, mode, rdev);
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->state = CALLOC (1, child_count);
+	memcpy (local->state, pvt->state, child_count);
+	local->active = -1;
+
+	stateino = CALLOC (1, child_count);
+	inode_ctx_put (loc->inode, this, (uint64_t)(long)stateino);
+
+	for (i = 0; i < child_count; i++) {
+		if (local->state[i]) {
+			local->call_count++;
+			if (local->active == -1) 
+				local->active = i;
+		}
+	}
+
+	STACK_WIND (frame,
+		    ha_mknod_cbk,
+		    HA_ACTIVE_CHILD(this, local),
+		    HA_ACTIVE_CHILD(this, local)->fops->mknod,
+		    loc, mode, rdev);
+	return 0;
+}
+
+
+int
+ha_mkdir_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.mkdir.loc.path, op_ret, op_errno);
+	}
+	inode_ctx_get (local->stub->args.mkdir.loc.inode, 
+		       this, &tmp_stateino);  
+	stateino = (char *)(long)tmp_stateino;
+
+	if (op_ret == 0)
+		stateino[i] = 1;
+
+	LOCK (&frame->lock);
+	cnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (cnt == 0) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      local->stub->args.mkdir.loc.inode,
+			      &local->buf);
+		call_stub_destroy (stub);
+	}
+	return 0;
+}
+
+int32_t
+ha_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+	
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		local->op_errno = op_errno;
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.mkdir.loc.path, op_ret, op_errno);
+	}
+
+	inode_ctx_get (local->stub->args.mkdir.loc.inode, 
+		       this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+
+	if (op_ret == 0) {
+		stateino[i] = 1;
+		local->op_ret = 0;
+		local->first_success = 1;
+		local->buf = *buf;
+	}
+	cnt = --local->call_count;
+	for (i = local->active + 1; i < child_count; i++) {
+		if (local->state[i])
+			break;
+	}
+
+	if (cnt == 0 || i == child_count) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		stub = local->stub;
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, local->stub->args.mkdir.loc.inode, &local->buf);
+		call_stub_destroy (stub);
+		return 0;
+	}
+
+	local->active = i;
+
+	if (local->first_success == 0) {
+		STACK_WIND (frame,
+			    ha_mkdir_cbk,
+			    children[i],
+			    children[i]->fops->mkdir,
+			    &local->stub->args.mkdir.loc,
+			    local->stub->args.mkdir.mode);
+		return 0;
+	}
+	cnt = local->call_count;
+
+	for (; i < child_count; i++) {
+		if (local->state[i]) {
+			STACK_WIND (frame,
+				    ha_mkdir_lookup_cbk,
+				    children[i],
+				    children[i]->fops->lookup,
+				    &local->stub->args.mkdir.loc,
+				    0);
+			if (--cnt == 0)
+				break;
+		}
+	}
+	return 0;
+}
+
+int32_t
+ha_mkdir (call_frame_t *frame,
+	  xlator_t *this,
+	  loc_t *loc,
+	  mode_t mode)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int child_count = 0, i = 0;
+	char *stateino = NULL;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+
+	frame->local = local = CALLOC (1, sizeof (*local));
+	local->stub = fop_mkdir_stub (frame, ha_mkdir, loc, mode);
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->state = CALLOC (1, child_count);
+	memcpy (local->state, pvt->state, child_count);
+	local->active = -1;
+
+	stateino = CALLOC (1, child_count);
+	inode_ctx_put (loc->inode, this, (uint64_t)(long)stateino);
+	for (i = 0; i < child_count; i++) {
+		if (local->state[i]) {
+			local->call_count++;
+			if (local->active == -1)
+				local->active = i;
+		}
+	}
+
+	STACK_WIND (frame,
+		    ha_mkdir_cbk,
+		    HA_ACTIVE_CHILD(this, local),
+		    HA_ACTIVE_CHILD(this, local)->fops->mkdir,
+		    loc, mode);
+	return 0;
+}
+
+ int32_t
+ha_unlink_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame, op_ret, op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_unlink (call_frame_t *frame,
+	   xlator_t *this,
+	   loc_t *loc)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_unlink_stub (frame, ha_unlink, loc);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_unlink_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->unlink,
+			   loc);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+ int32_t
+ha_rmdir_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_rmdir (call_frame_t *frame,
+	  xlator_t *this,
+	  loc_t *loc)
+{
+	ha_local_t *local = frame->local;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_rmdir_stub (frame, ha_rmdir, loc);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_rmdir_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->rmdir,
+			   loc);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+
+int
+ha_symlink_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.symlink.loc.path, op_ret, op_errno);
+	}
+	inode_ctx_get (local->stub->args.symlink.loc.inode,
+		       this, &tmp_stateino);  
+	stateino = (char *)(long)tmp_stateino;
+
+	if (op_ret == 0)
+		stateino[i] = 1;
+
+	LOCK (&frame->lock);
+	cnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (cnt == 0) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      local->stub->args.symlink.loc.inode,
+			      &local->buf);
+		call_stub_destroy (stub);
+	}
+	return 0;
+}
+
+int32_t
+ha_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		local->op_errno = op_errno;
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.symlink.loc.path, op_ret, op_errno);
+	}
+	inode_ctx_get (local->stub->args.symlink.loc.inode, 
+		       this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+
+	if (op_ret == 0) {
+		stateino[i] = 1;
+		local->op_ret = 0;
+		local->first_success = 1;
+		local->buf = *buf;
+	}
+	cnt = --local->call_count;
+	for (i = local->active + 1; i < child_count; i++) {
+		if (local->state[i])
+			break;
+	}
+
+	if (cnt == 0 || i == child_count) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		stub = local->stub;
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, 
+			      local->stub->args.symlink.loc.inode, &local->buf);
+		call_stub_destroy (stub);
+		return 0;
+	}
+
+	local->active = i;
+
+	if (local->first_success == 0) {
+		STACK_WIND (frame,
+			    ha_symlink_cbk,
+			    children[i],
+			    children[i]->fops->symlink,
+			    local->stub->args.symlink.linkname,
+			    &local->stub->args.symlink.loc);
+		return 0;
+	}
+	cnt = local->call_count;
+
+	for (; i < child_count; i++) {
+		if (local->state[i]) {
+			STACK_WIND (frame,
+				    ha_symlink_lookup_cbk,
+				    children[i],
+				    children[i]->fops->lookup,
+				    &local->stub->args.symlink.loc,
+				    0);
+			if (--cnt == 0)
+				break;
+		}
+	}
+	return 0;
+}
+
+int32_t
+ha_symlink (call_frame_t *frame,
+	    xlator_t *this,
+	    const char *linkname,
+	    loc_t *loc)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int child_count = 0, i = 0;
+	char *stateino = NULL;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+
+	frame->local = local = CALLOC (1, sizeof (*local));
+	local->stub = fop_symlink_stub (frame, ha_symlink, linkname, loc);
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->state = CALLOC (1, child_count);
+	memcpy (local->state, pvt->state, child_count);
+	local->active = -1;
+
+	stateino = CALLOC (1, child_count);
+	inode_ctx_put (loc->inode, this, (uint64_t)(long)stateino);
+
+	for (i = 0; i < child_count; i++) {
+		if (local->state[i]) {
+			local->call_count++;
+			if (local->active == -1) {
+				local->active = i;
+			}
+		}
+	}
+
+	STACK_WIND (frame,
+		    ha_symlink_cbk,
+		    HA_ACTIVE_CHILD(this, local),
+		    HA_ACTIVE_CHILD(this, local)->fops->symlink,
+		    linkname, loc);
+	return 0;
+}
+
+ int32_t
+ha_rename_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno,
+	       struct stat *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame, op_ret, op_errno, buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_rename (call_frame_t *frame,
+	   xlator_t *this,
+	   loc_t *oldloc,
+	   loc_t *newloc)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, oldloc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_rename_stub (frame, ha_rename, oldloc, newloc);
+	STACK_WIND_COOKIE (frame,
+			   ha_rename_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->rename,
+			   oldloc, newloc);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+int
+ha_link_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.link.newloc.path, op_ret, op_errno);
+	}
+	inode_ctx_get (local->stub->args.link.newloc.inode, 
+		       this, &tmp_stateino);  
+	stateino = (char *)(long)tmp_stateino;
+
+	if (op_ret == 0)
+		stateino[i] = 1;
+
+	LOCK (&frame->lock);
+	cnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (cnt == 0) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      local->stub->args.link.oldloc.inode,
+			      &local->buf);
+		call_stub_destroy (stub);
+	}
+	return 0;
+}
+
+int32_t
+ha_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	int child_count = 0, i = 0, cnt = 0;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	for (i = 0; i < child_count; i++)
+		if (prev_frame->this == children[i])
+			break;
+
+	if (op_ret == -1) {
+		local->op_errno = op_errno;
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.link.newloc.path, op_ret, op_errno);
+	}
+	inode_ctx_get (local->stub->args.link.newloc.inode, 
+		       this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+
+	if (op_ret == 0) {
+		stateino[i] = 1;
+		local->op_ret = 0;
+		local->first_success = 1;
+		local->buf = *buf;
+	}
+	cnt = --local->call_count;
+	for (i = local->active + 1; i < child_count; i++) {
+		if (local->state[i])
+			break;
+	}
+
+	if (cnt == 0 || i == child_count) {
+		call_stub_t *stub = local->stub;
+		FREE (local->state);
+		stub = local->stub;
+		STACK_UNWIND (frame, local->op_ret, local->op_errno, local->stub->args.link.oldloc.inode, &local->buf);
+		call_stub_destroy (stub);
+		return 0;
+	}
+
+	local->active = i;
+
+	if (local->first_success == 0) {
+		STACK_WIND (frame,
+			    ha_link_cbk,
+			    children[i],
+			    children[i]->fops->link,
+			    &local->stub->args.link.oldloc,
+			    &local->stub->args.link.newloc);
+		return 0;
+	}
+	cnt = local->call_count;
+
+	for (; i < child_count; i++) {
+		if (local->state[i]) {
+			STACK_WIND (frame,
+				    ha_link_lookup_cbk,
+				    children[i],
+				    children[i]->fops->lookup,
+				    &local->stub->args.link.newloc,
+				    0);
+			if (--cnt == 0)
+				break;
+		}
+	}
+	return 0;
+}
+
+int32_t
+ha_link (call_frame_t *frame,
+	 xlator_t *this,
+	 loc_t *oldloc,
+	 loc_t *newloc)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int child_count = 0, i = 0;
+	char *stateino = NULL;
+	int32_t ret = 0;
+	uint64_t tmp_stateino = 0;
+
+	ret = inode_ctx_get (newloc->inode, this, &tmp_stateino);
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "dict_ptr_error()");
+	}
+	stateino = (char *)(long)tmp_stateino;
+
+	if (stateino == NULL) {
+		gf_log (this->name, GF_LOG_ERROR, 
+			"newloc->inode's ctx is NULL, returning EINVAL");
+		STACK_UNWIND (frame, -1, EINVAL, oldloc->inode, NULL);
+		return 0;
+	}
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+
+	frame->local = local = CALLOC (1, sizeof (*local));
+	local->stub = fop_link_stub (frame, ha_link, oldloc, newloc);
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->state = CALLOC (1, child_count);
+	memcpy (local->state, pvt->state, child_count);
+	local->active = -1;
+
+	for (i = 0; i < child_count; i++) {
+		if (local->state[i]) {
+			local->call_count++;
+			if (local->active == -1)
+				local->active = i;
+		}
+	}
+
+	STACK_WIND (frame,
+		    ha_link_cbk,
+		    HA_ACTIVE_CHILD(this, local),
+		    HA_ACTIVE_CHILD(this, local)->fops->link,
+		    oldloc,
+		    newloc);
+	return 0;
+}
+
+int32_t
+ha_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)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int i, child_count = 0, cnt = 0, ret = 0;
+	char *stateino = NULL;
+	hafd_t *hafdp = NULL;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	uint64_t tmp_stateino = 0;
+	uint64_t tmp_hafdp = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	ret = inode_ctx_get (local->stub->args.create.loc.inode, 
+			     this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "dict_to_ptr() error");
+		/* FIXME: handle */
+	}
+	ret = fd_ctx_get (local->stub->args.create.fd, this, &tmp_hafdp);
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "dict_to_ptr() error");
+		/* FIXME: handle */
+	}
+	hafdp = (hafd_t *)(long)tmp_hafdp;
+
+	for (i = 0; i < child_count; i++) {
+		if (prev_frame->this == children[i])
+			break;
+	}
+
+	if (op_ret == -1) {
+		local->op_errno = op_errno;
+		gf_log (this->name, GF_LOG_ERROR, "(path=%s) (op_ret=%d op_errno=%d)", local->stub->args.create.loc.path, op_ret, op_errno);
+	}
+	if (op_ret != -1) {
+		stateino[i] = 1;
+		hafdp->fdstate[i] = 1;
+		if (local->op_ret == -1) {
+			local->op_ret = 0;
+			local->buf = *buf;
+			local->first_success = 1;
+		}
+		local->stub->args.create.flags &= (~O_EXCL);
+	}
+	LOCK (&frame->lock);
+	cnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	for (i = local->active + 1; i < child_count; i++) {
+		if (local->state[i])
+			break;
+	}
+
+	if (cnt == 0 || i == child_count) {
+		char *state = local->state;
+		call_stub_t *stub = local->stub;
+		STACK_UNWIND (frame, local->op_ret, local->op_errno,
+			      stub->args.create.fd,
+			      stub->args.create.loc.inode, &local->buf);
+		FREE (state);
+		call_stub_destroy (stub);
+		return 0;
+	}
+	local->active = i;
+	cnt = local->call_count;
+	for (; i < child_count; i++) {
+		if (local->state[i]) {
+			STACK_WIND (frame,
+				    ha_create_cbk,
+				    children[i],
+				    children[i]->fops->create,
+				    &local->stub->args.create.loc,
+				    local->stub->args.create.flags,
+				    local->stub->args.create.mode,
+				    local->stub->args.create.fd);
+			if ((local->first_success == 0) || (cnt == 0))
+				break;
+		}
+	}
+	return 0;
+}
+
+int32_t
+ha_create (call_frame_t *frame,
+	   xlator_t *this,
+	   loc_t *loc,
+	   int32_t flags,
+	   mode_t mode, fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	int i, child_count = 0;
+	char *stateino = NULL;
+	xlator_t **children = NULL;
+	hafd_t *hafdp = NULL;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	children = pvt->children;
+
+	if (local == NULL) {
+		local = frame->local = CALLOC (1, sizeof (*local));
+		local->stub = fop_create_stub (frame, ha_create, loc, flags, mode, fd);
+		local->state = CALLOC (1, child_count);
+		local->active = -1;
+		local->op_ret = -1;
+		local->op_errno = ENOTCONN;
+		memcpy (local->state, pvt->state, child_count);
+
+		for (i = 0; i < pvt->child_count; i++) {
+			if (local->state[i]) {
+				local->call_count++;
+				if (local->active == -1)
+					local->active = i;
+			}
+		}
+		/* FIXME handle active -1 */
+		stateino = CALLOC (1, child_count);
+		hafdp = CALLOC (1, sizeof (*hafdp));
+		hafdp->fdstate = CALLOC (1, child_count);
+		hafdp->path = strdup(loc->path);
+		LOCK_INIT (&hafdp->lock);
+		fd_ctx_set (fd, this, (uint64_t)(long)hafdp);
+		inode_ctx_put (loc->inode, this, (uint64_t)(long)stateino);
+	}
+
+	STACK_WIND (frame,
+		    ha_create_cbk,
+		    children[local->active],
+		    children[local->active]->fops->create,
+		    loc, flags, mode, fd);
+	return 0;
+}
+
+ int32_t
+ha_open_cbk (call_frame_t *frame,
+	     void *cookie,
+	     xlator_t *this,
+	     int32_t op_ret,
+	     int32_t op_errno,
+	     fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	xlator_t **children = NULL;
+	int i = 0, child_count = 0, callcnt = 0, ret = 0;
+	call_frame_t *prev_frame = NULL;
+	hafd_t *hafdp = NULL;
+	uint64_t tmp_hafdp = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	children = pvt->children;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+
+	ret = fd_ctx_get (local->fd, this, &tmp_hafdp);
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "dict_ptr_error()");
+	}
+	hafdp = (hafd_t *)(long)tmp_hafdp;
+
+	for (i = 0; i < child_count; i++)
+		if (children[i] == prev_frame->this)
+			break;
+	LOCK (&frame->lock);
+	if (op_ret != -1) {
+		hafdp->fdstate[i] = 1;
+		local->op_ret = 0;
+	}
+	if (op_ret == -1 && op_errno != ENOTCONN)
+		local->op_errno = op_errno;
+	callcnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (callcnt == 0) {
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      local->fd);
+	}
+	return 0;
+}
+
+int32_t
+ha_open (call_frame_t *frame,
+	 xlator_t *this,
+	 loc_t *loc,
+	 int32_t flags, fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	xlator_t **children = NULL;
+	int cnt = 0, i, child_count = 0, ret = 0;
+	hafd_t *hafdp = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	children = pvt->children;
+	child_count = pvt->child_count;
+
+
+	local = frame->local = CALLOC (1, sizeof (*local));
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->fd = fd;
+
+	hafdp = CALLOC (1, sizeof (*hafdp));
+	hafdp->fdstate = CALLOC (1, child_count);
+	hafdp->path = strdup (loc->path);
+	hafdp->active = -1;
+	if (pvt->pref_subvol == -1) {
+		hafdp->active = fd->inode->ino % child_count;
+	}
+
+	LOCK_INIT (&hafdp->lock);
+	fd_ctx_set (fd, this, (uint64_t)(long)hafdp);
+	ret = inode_ctx_get (loc->inode, this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+
+	for (i = 0; i < child_count; i++)
+		if (stateino[i])
+			cnt++;
+	local->call_count = cnt;
+	for (i = 0; i < child_count; i++) {
+		if (stateino[i]) {
+			STACK_WIND (frame,
+				    ha_open_cbk,
+				    children[i],
+				    children[i]->fops->open,
+				    loc, flags, fd);
+			if (--cnt == 0)
+				break;
+		}
+	}
+	return 0;
+}
+
+ int32_t
+ha_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)
+{
+	int ret = 0;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      vector,
+			      count,
+			      stbuf);
+	}
+	return 0;
+}
+
+int32_t
+ha_readv (call_frame_t *frame,
+	  xlator_t *this,
+	  fd_t *fd,
+	  size_t size,
+	  off_t offset)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_readv_stub (frame, ha_readv, fd, size, offset);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_readv_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->readv,
+			   fd,
+			   size,
+			   offset);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+ int32_t
+ha_writev_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno,
+	       struct stat *stbuf)
+{
+	int ret = 0;
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      stbuf);
+	}
+	return 0;
+}
+
+int32_t
+ha_writev (call_frame_t *frame,
+	   xlator_t *this,
+	   fd_t *fd,
+	   struct iovec *vector,
+	   int32_t count,
+	   off_t off)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_writev_stub (frame, ha_writev, fd, vector, count, off);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_writev_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->writev,
+			   fd,
+			   vector,
+			   count,
+			   off);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;	
+}
+
+ int32_t
+ha_flush_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno)
+{
+	int ret = 0;
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_flush (call_frame_t *frame,
+	  xlator_t *this,
+	  fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_flush_stub (frame, ha_flush, fd);
+	STACK_WIND_COOKIE (frame,
+			   ha_flush_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->flush,
+			   fd);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+
+ int32_t
+ha_fsync_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno)
+{
+	int ret = 0;
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_fsync (call_frame_t *frame,
+	  xlator_t *this,
+	  fd_t *fd,
+	  int32_t flags)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_fsync_stub (frame, ha_fsync, fd, flags);
+	STACK_WIND_COOKIE (frame,
+			   ha_fsync_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->fsync,
+			   fd,
+			   flags);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+ int32_t
+ha_fstat_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno,
+	      struct stat *buf)
+{
+	int ret = 0;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_fstat (call_frame_t *frame,
+	  xlator_t *this,
+	  fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_fstat_stub (frame, ha_fstat, fd);
+	STACK_WIND_COOKIE (frame,
+			   ha_fstat_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->fstat,
+			   fd);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+int32_t
+ha_opendir_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	xlator_t **children = NULL;
+	int i = 0, child_count = 0, callcnt = 0, ret = 0;
+	call_frame_t *prev_frame = NULL;
+	hafd_t *hafdp = NULL;
+	uint64_t tmp_hafdp = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	children = pvt->children;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+
+	ret = fd_ctx_get (local->fd, this, &tmp_hafdp);
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "dict_ptr_error()");
+	}
+	hafdp = (hafd_t *)(long)tmp_hafdp;
+
+	for (i = 0; i < child_count; i++)
+		if (children[i] == prev_frame->this)
+			break;
+	LOCK (&frame->lock);
+	if (op_ret != -1) {
+		hafdp->fdstate[i] = 1;
+		local->op_ret = 0;
+	}
+	if (op_ret == -1 && op_errno != ENOTCONN)
+		local->op_errno = op_errno;
+	callcnt = --local->call_count;
+	UNLOCK (&frame->lock);
+
+	if (callcnt == 0) {
+		STACK_UNWIND (frame,
+			      local->op_ret,
+			      local->op_errno,
+			      local->fd);
+	}
+	return 0;
+}
+
+int32_t
+ha_opendir (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc, fd_t *fd)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	char *stateino = NULL;
+	xlator_t **children = NULL;
+	int cnt = 0, i, child_count = 0, ret = 0;
+	hafd_t *hafdp = NULL;
+	uint64_t tmp_stateino = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	children = pvt->children;
+	child_count = pvt->child_count;
+
+	local = frame->local = CALLOC (1, sizeof (*local));
+	local->op_ret = -1;
+	local->op_errno = ENOTCONN;
+	local->fd = fd;
+
+	hafdp = CALLOC (1, sizeof (*hafdp));
+	hafdp->fdstate = CALLOC (1, child_count);
+	hafdp->path = strdup (loc->path);
+	LOCK_INIT (&hafdp->lock);
+	fd_ctx_set (fd, this, (uint64_t)(long)hafdp);
+	ret = inode_ctx_get (loc->inode, this, &tmp_stateino);
+	stateino = (char *)(long)tmp_stateino;
+	
+	if (ret != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "inode_ctx_get() error");
+	}
+	for (i = 0; i < child_count; i++)
+		if (stateino[i])
+			cnt++;
+	local->call_count = cnt;
+	for (i = 0; i < child_count; i++) {
+		if (stateino[i]) {
+			STACK_WIND (frame,
+				    ha_opendir_cbk,
+				    children[i],
+				    children[i]->fops->opendir,
+				    loc, fd);
+			if (--cnt == 0)
+				break;
+		}
+	}
+	return 0;
+}
+
+ int32_t
+ha_getdents_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 dir_entry_t *entries,
+		 int32_t count)
+{
+	int ret = 0;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      entries,
+			      count);
+	}
+	return 0;
+}
+
+int32_t
+ha_getdents (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd,
+	     size_t size,
+	     off_t offset,
+	     int32_t flag)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_getdents_stub (frame, ha_getdents, fd, size, offset, flag);
+	STACK_WIND_COOKIE (frame,
+			   ha_getdents_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->getdents,
+			   fd,
+			   size,
+			   offset,
+			   flag);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL, 0);
+	return 0;
+}
+
+ int32_t
+ha_setdents_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno)
+{
+	int ret = 0;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_setdents (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd,
+	     int32_t flags,
+	     dir_entry_t *entries,
+	     int32_t count)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+
+	local->stub = fop_setdents_stub (frame, ha_setdents, fd, flags, entries, count);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_setdents_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->setdents,
+			   fd,
+			   flags,
+			   entries,
+			   count);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+ int32_t
+ha_fsyncdir_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno)
+{
+	int ret = 0;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_fsyncdir (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd,
+	     int32_t flags)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_fsyncdir_stub (frame, ha_fsyncdir, fd, flags);
+	STACK_WIND_COOKIE (frame,
+			   ha_fsyncdir_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->fsyncdir,
+			   fd,
+			   flags);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+
+ int32_t
+ha_statfs_cbk (call_frame_t *frame,
+	       void *cookie,
+	       xlator_t *this,
+	       int32_t op_ret,
+	       int32_t op_errno,
+	       struct statvfs *buf)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      buf);
+	}
+	return 0;
+}
+
+int32_t
+ha_statfs (call_frame_t *frame,
+	   xlator_t *this,
+	   loc_t *loc)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+
+	local->stub = fop_statfs_stub (frame, ha_statfs, loc);
+	STACK_WIND_COOKIE (frame,
+			   ha_statfs_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->statfs,
+			   loc);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+ int32_t
+ha_setxattr_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_setxattr (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     dict_t *dict,
+	     int32_t flags)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_setxattr_stub (frame, ha_setxattr, loc, dict, flags);
+	STACK_WIND_COOKIE (frame,
+			   ha_setxattr_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->setxattr,
+			   loc,
+			   dict,
+			   flags);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+ int32_t
+ha_getxattr_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 dict_t *dict)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      dict);
+	}
+	return 0;
+}
+
+int32_t
+ha_getxattr (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     const char *name)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_getxattr_stub (frame, ha_getxattr, loc, name);
+	STACK_WIND_COOKIE (frame,
+			   ha_getxattr_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->getxattr,
+			   loc,
+			   name);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL);
+	return 0;
+}
+
+int32_t
+ha_xattrop_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		dict_t *dict)
+{
+	int ret = -1;
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame, op_ret, op_errno, dict);
+	}
+	return 0;
+}
+
+
+int32_t
+ha_xattrop (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc,
+	    gf_xattrop_flags_t flags,
+	    dict_t *dict)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+
+	local->stub = fop_xattrop_stub (frame, ha_xattrop, loc, flags, dict);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_xattrop_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->xattrop,
+			   loc,
+			   flags,
+			   dict);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, dict);
+	return 0;
+}
+
+int32_t
+ha_fxattrop_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 dict_t *dict)
+{
+	int ret = -1;
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0)
+		STACK_UNWIND (frame, op_ret, op_errno, dict);
+	return 0;
+}
+
+int32_t
+ha_fxattrop (call_frame_t *frame,
+	     xlator_t *this,
+	     fd_t *fd,
+	     gf_xattrop_flags_t flags,
+	     dict_t *dict)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_fxattrop_stub (frame, ha_fxattrop, fd, flags, dict);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_fxattrop_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->fxattrop,
+			   fd,
+			   flags,
+			   dict);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, dict);
+	return 0;
+}
+
+ int32_t
+ha_removexattr_cbk (call_frame_t *frame,
+		    void *cookie,
+		    xlator_t *this,
+		    int32_t op_ret,
+		    int32_t op_errno)
+{
+	int ret = -1;
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_removexattr (call_frame_t *frame,
+		xlator_t *this,
+		loc_t *loc,
+		const char *name)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	
+	local->stub = fop_removexattr_stub (frame, ha_removexattr, loc, name);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_removexattr_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->removexattr,
+			   loc,
+			   name);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+int32_t
+ha_lk_setlk_unlck_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno,
+		       struct flock *lock)
+{
+	ha_local_t *local = NULL;
+	int cnt = 0;
+	call_stub_t *stub = NULL;
+
+	local = frame->local;
+
+	LOCK (&frame->lock);
+	cnt = --local->call_count;
+	if (op_ret == 0)
+		local->op_ret = 0;
+	UNLOCK (&frame->lock);
+
+	if (cnt == 0) {
+		stub = local->stub;
+		FREE (local->state);
+		if (stub->args.lk.lock.l_type == F_UNLCK) {
+			STACK_UNWIND (frame, local->op_ret, local->op_errno, &stub->args.lk.lock);
+		} else {
+			STACK_UNWIND (frame, -1, EIO, NULL);
+		}
+		call_stub_destroy (stub);
+	}
+	return 0;
+}
+
+int32_t
+ha_lk_setlk_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 struct flock *lock)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	xlator_t **children = NULL;
+	int i = 0, cnt = 0, j = 0;
+	int child_count = 0;
+	call_frame_t *prev_frame = NULL;
+	char *state = NULL;
+
+	local = frame->local;
+	pvt = this->private;
+	children = pvt->children;
+	child_count = pvt->child_count;
+	prev_frame = cookie;
+	state = local->state;
+
+	if (op_ret == 0)
+		local->op_ret = 0;
+
+	if ((op_ret == 0) || (op_ret == -1 && op_errno == ENOTCONN)) {
+		for (i = 0; i < child_count; i++) {
+			if (prev_frame->this == cookie)
+				break;
+		}
+		i++;
+		for (; i < child_count; i++) {
+			if (local->state[i])
+				break;
+		}
+		if (i == child_count) {
+			call_stub_t *stub = local->stub;
+			FREE (local->state);
+			STACK_UNWIND (frame, 0, op_errno, &stub->args.lk.lock);
+			call_stub_destroy (stub);
+			return 0;
+		}
+		STACK_WIND (frame,
+			    ha_lk_setlk_cbk,
+			    children[i],
+			    children[i]->fops->lk,
+			    local->stub->args.lk.fd,
+			    local->stub->args.lk.cmd,
+			    &local->stub->args.lk.lock);
+		return 0;
+	} else {
+		for (i = 0; i < child_count; i++) {
+			if (prev_frame->this == cookie)
+				break;
+		}
+		cnt = 0;
+		for (j = 0; j < i; j++) {
+			if (state[i])
+				cnt++;
+		}
+		if (cnt) {
+			struct flock lock;
+			lock = local->stub->args.lk.lock;
+			for (i = 0; i < child_count; i++) {
+				if (state[i]) {
+					STACK_WIND (frame,
+						    ha_lk_setlk_unlck_cbk,
+						    children[i],
+						    children[i]->fops->lk,
+						    local->stub->args.lk.fd,
+						    local->stub->args.lk.cmd,
+						    &lock);
+					if (--cnt == 0)
+						break;
+				}
+			}
+			return 0;
+		} else {
+			FREE (local->state);
+			call_stub_destroy (local->stub);
+			STACK_UNWIND (frame,
+				      op_ret,
+				      op_errno,
+				      lock);
+			return 0;
+		}
+	}
+}
+
+int32_t
+ha_lk_getlk_cbk (call_frame_t *frame,
+		 void *cookie,
+		 xlator_t *this,
+		 int32_t op_ret,
+		 int32_t op_errno,
+		 struct flock *lock)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	fd_t *fd = NULL;
+	int child_count = 0, i = 0;
+	xlator_t **children = NULL;
+	call_frame_t *prev_frame = NULL;
+
+	local = frame->local;
+	pvt = this->private;
+	fd = local->stub->args.lk.fd;
+	child_count = pvt->child_count;
+	children = pvt->children;
+	prev_frame = cookie;
+
+	if (op_ret == 0) {
+		FREE (local->state);
+		call_stub_destroy (local->stub);
+		STACK_UNWIND (frame, 0, 0, lock);
+		return 0;
+	}
+
+	for (i = 0; i < child_count; i++) {
+		if (prev_frame->this == children[i])
+			break;
+	}
+
+	for (; i < child_count; i++) {
+		if (local->state[i])
+			break;
+	}
+
+	if (i == child_count) {
+		FREE (local->state);
+		call_stub_destroy (local->stub);
+		STACK_UNWIND (frame, op_ret, op_errno, lock);
+		return 0;
+	}
+
+	STACK_WIND (frame,
+		    ha_lk_getlk_cbk,
+		    children[i],
+		    children[i]->fops->lk,
+		    fd,
+		    local->stub->args.lk.cmd,
+		    &local->stub->args.lk.lock);
+	return 0;
+}
+
+int32_t
+ha_lk (call_frame_t *frame,
+       xlator_t *this,
+       fd_t *fd,
+       int32_t cmd,
+       struct flock *lock)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	hafd_t *hafdp = NULL;
+	char *state = NULL;
+	int child_count = 0, i = 0, cnt = 0, ret = 0;
+	xlator_t **children = NULL;
+	uint64_t tmp_hafdp = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	child_count = pvt->child_count;
+	children = pvt->children;
+	ret = fd_ctx_get (fd, this, &tmp_hafdp);
+	if (ret < 0)
+		gf_log (this->name, GF_LOG_ERROR, "fd_ctx_get failed");
+
+	if (local == NULL) {
+		local = frame->local = CALLOC (1, sizeof (*local));
+		local->active = -1;
+		local->op_ret = -1;
+		local->op_errno = ENOTCONN;
+	}
+	hafdp = (hafd_t *)(long)tmp_hafdp;
+
+	if (local->active == -1) {
+		STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+		return 0;
+	}
+
+	local->stub = fop_lk_stub (frame, ha_lk, fd, cmd, lock);
+	local->state = CALLOC (1, child_count);
+	state = hafdp->fdstate;
+	LOCK (&hafdp->lock);
+	memcpy (local->state, state, child_count);
+	UNLOCK (&hafdp->lock);
+	if (cmd == F_GETLK) {
+		for (i = 0; i < child_count; i++) {
+			if (local->state[i])
+				break;
+		}
+		STACK_WIND (frame,
+			    ha_lk_getlk_cbk,
+			    children[i],
+			    children[i]->fops->lk,
+			    fd,
+			    cmd,
+			    lock);
+	} else if (cmd == F_SETLK && lock->l_type == F_UNLCK) {
+		for (i = 0; i < child_count; i++) {
+			if (local->state[i])
+				local->call_count++;
+		}
+		cnt = local->call_count;
+		for (i = 0; i < child_count; i++) {
+			if (local->state[i]) {
+				STACK_WIND (frame,
+					    ha_lk_setlk_unlck_cbk,
+					    children[i],
+					    children[i]->fops->lk,
+					    fd, cmd, lock);
+				if (--cnt == 0)
+					break;
+			}
+		}
+	} else {
+		for (i = 0; i < child_count; i++) {
+			if (local->state[i])
+				break;
+		}
+		STACK_WIND (frame,
+			    ha_lk_setlk_cbk,
+			    children[i],
+			    children[i]->fops->lk,
+			    fd,
+			    cmd,
+			    lock);
+	}
+	return 0;
+}
+
+ int32_t
+ha_inode_entry_lk_cbk (call_frame_t *frame,
+		       void *cookie,
+		       xlator_t *this,
+		       int32_t op_ret,
+		       int32_t op_errno)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno);
+	}
+	return 0;
+}
+
+int32_t
+ha_inodelk (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc,
+	    int32_t cmd,
+	    struct flock *lock)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_inodelk_stub (frame, ha_inodelk, loc, cmd, lock);
+	STACK_WIND_COOKIE (frame,
+			   ha_inode_entry_lk_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->inodelk,
+			   loc,
+			   cmd,
+			   lock);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+int32_t
+ha_entrylk (call_frame_t *frame,
+	    xlator_t *this,
+	    loc_t *loc,
+	    const char *basename,
+	    entrylk_cmd cmd,
+	    entrylk_type type)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_entrylk_stub (frame, ha_entrylk, loc, basename, cmd, type);
+	STACK_WIND_COOKIE (frame,
+			   ha_inode_entry_lk_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->entrylk,
+			   loc, basename, cmd, type);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno);
+	return 0;
+}
+
+ int32_t
+ha_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)
+{
+	int ret = -1;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0) {
+		STACK_UNWIND (frame,
+			      op_ret,
+			      op_errno,
+			      file_checksum,
+			      dir_checksum);
+	}
+	return 0;
+}
+
+int32_t
+ha_checksum (call_frame_t *frame,
+	     xlator_t *this,
+	     loc_t *loc,
+	     int32_t flag)
+{
+	int op_errno = 0;
+	ha_local_t *local = NULL;
+
+	op_errno = ha_alloc_init_inode (frame, loc->inode);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_checksum_stub (frame, ha_checksum, loc, flag);
+
+	STACK_WIND_COOKIE (frame,
+			   ha_checksum_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->checksum,
+			   loc,
+			   flag);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, op_errno, NULL, NULL);
+	return 0;
+}
+
+int32_t
+ha_readdir_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		gf_dirent_t *entries)
+{
+	int ret = 0;
+
+	ret = ha_handle_cbk (frame, cookie, op_ret, op_errno);
+	if (ret == 0)
+		STACK_UNWIND (frame, op_ret, op_errno, entries);
+	return 0;
+}
+
+int32_t
+ha_readdir (call_frame_t *frame,
+	    xlator_t *this,
+	    fd_t *fd,
+	    size_t size,
+	    off_t off)
+{
+	ha_local_t *local = NULL;
+	int op_errno = 0;
+
+	op_errno = ha_alloc_init_fd (frame, fd);
+	if (op_errno < 0) {
+		op_errno = -op_errno;
+		goto err;
+	}
+	local = frame->local;
+	local->stub = fop_readdir_stub (frame, ha_readdir, fd, size, off);
+	STACK_WIND_COOKIE (frame,
+			   ha_readdir_cbk,
+			   (void *)(long)local->active,
+			   HA_ACTIVE_CHILD(this, local),
+			   HA_ACTIVE_CHILD(this, local)->fops->readdir,
+			   fd, size, off);
+	return 0;
+err:
+	STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+	return 0;
+}
+
+/* Management operations */
+
+ int32_t
+ha_stats_cbk (call_frame_t *frame,
+	      void *cookie,
+	      xlator_t *this,
+	      int32_t op_ret,
+	      int32_t op_errno,
+	      struct xlator_stats *stats)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	int i = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	if (op_ret == -1 && op_errno == ENOTCONN) {
+		for (i = 0; i < pvt->child_count; i++) {
+			if (prev_frame->this == children[i])
+				break;
+		}
+		i++;
+		for (; i < pvt->child_count; i++) {
+			if (pvt->state[i])
+				break;
+		}
+
+		if (i == pvt->child_count) {
+			STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+			return 0;
+		}
+		STACK_WIND (frame,
+			    ha_stats_cbk,
+			    children[i],
+			    children[i]->mops->stats,
+			    local->flags);
+		return 0;
+	}
+
+	STACK_UNWIND (frame,
+		      op_ret,
+		      op_errno,
+		      stats);
+	return 0;
+}
+
+int32_t
+ha_stats (call_frame_t *frame,
+	  xlator_t *this,
+	  int32_t flags)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	xlator_t **children = NULL;
+	int i = 0;
+
+	local = frame->local = CALLOC (1, sizeof (*local));
+	pvt = this->private;
+	children = pvt->children;
+	for (i = 0; i < pvt->child_count; i++) {
+		if (pvt->state[i])
+			break;
+	}
+
+	if (i == pvt->child_count) {
+		STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+		return 0;
+	}
+	local->flags = flags;
+
+	STACK_WIND (frame,
+		    ha_stats_cbk,
+		    children[i],
+		    children[i]->mops->stats,
+		    flags);
+	return 0;
+}
+
+
+int32_t
+ha_getspec_cbk (call_frame_t *frame,
+		void *cookie,
+		xlator_t *this,
+		int32_t op_ret,
+		int32_t op_errno,
+		char *spec_data)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	call_frame_t *prev_frame = NULL;
+	xlator_t **children = NULL;
+	int i = 0;
+
+	local = frame->local;
+	pvt = this->private;
+	prev_frame = cookie;
+	children = pvt->children;
+
+	if (op_ret == -1 && op_errno == ENOTCONN) {
+		for (i = 0; i < pvt->child_count; i++) {
+			if (prev_frame->this == children[i])
+				break;
+		}
+		i++;
+		for (; i < pvt->child_count; i++) {
+			if (pvt->state[i])
+				break;
+		}
+
+		if (i == pvt->child_count) {
+			STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+			return 0;
+		}
+		STACK_WIND (frame,
+			    ha_getspec_cbk,
+			    children[i],
+			    children[i]->mops->getspec,
+			    local->pattern,
+			    local->flags);
+		return 0;
+	}
+
+	STACK_UNWIND (frame,
+		      op_ret,
+		      op_errno,
+		      spec_data);
+	return 0;
+}
+
+int32_t
+ha_getspec (call_frame_t *frame,
+	    xlator_t *this,
+	    const char *key,
+	    int32_t flags)
+{
+	ha_local_t *local = NULL;
+	ha_private_t *pvt = NULL;
+	xlator_t **children = NULL;
+	int i = 0;
+
+	local = frame->local = CALLOC (1, sizeof (*local));
+	pvt = this->private;
+	children = pvt->children;
+
+	local = frame->local = CALLOC (1, sizeof (*local));
+	for (i = 0; i < pvt->child_count; i++) {
+		if (pvt->state[i])
+			break;
+	}
+
+	if (i == pvt->child_count) {
+		STACK_UNWIND (frame, -1, ENOTCONN, NULL);
+		return 0;
+	}
+	local->flags = flags;
+	local->pattern = (char *)key;
+
+	STACK_WIND (frame,
+		    ha_getspec_cbk,
+		    children[i],
+		    children[i]->mops->getspec,
+		    key, flags);
+	return 0;
+}
+
+int32_t
+ha_closedir (xlator_t *this,
+	     fd_t *fd)
+{
+	hafd_t *hafdp = NULL;
+	int op_errno = 0;
+	uint64_t tmp_hafdp = 0;
+
+	op_errno = fd_ctx_del (fd, this, &tmp_hafdp);
+	if (op_errno != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "fd_ctx_del() error");
+		return 0;
+	}
+	hafdp = (hafd_t *)(long)tmp_hafdp;
+
+	FREE (hafdp->fdstate);
+	FREE (hafdp->path);
+	LOCK_DESTROY (&hafdp->lock);
+	return 0;
+}
+
+int32_t
+ha_close (xlator_t *this,
+	  fd_t *fd)
+{
+	hafd_t *hafdp = NULL;
+	int op_errno = 0;
+	uint64_t tmp_hafdp = 0;
+
+	op_errno = fd_ctx_del (fd, this, &tmp_hafdp);
+	if (op_errno != 0) {
+		gf_log (this->name, GF_LOG_ERROR, "fd_ctx_del() error");
+		return 0;
+	}
+	hafdp = (hafd_t *)(long)tmp_hafdp;
+
+	FREE (hafdp->fdstate);
+	FREE (hafdp->path);
+	LOCK_DESTROY (&hafdp->lock);
+	return 0;
+}
+
+/* notify */
+int32_t
+notify (xlator_t *this,
+	int32_t event,
+	void *data,
+	...)
+{
+	ha_private_t *pvt = NULL;
+	int32_t i = 0, upcnt = 0;
+
+	pvt = this->private;
+	if (pvt == NULL) {
+		gf_log (this->name, GF_LOG_DEBUG, "got notify before init()");
+		return 0;
+	}
+
+	switch (event)
+	{
+	case GF_EVENT_CHILD_DOWN:
+	{
+		for (i = 0; i < pvt->child_count; i++) {
+			if (data == pvt->children[i])
+				break;
+		}
+	        gf_log (this->name, GF_LOG_DEBUG, "GF_EVENT_CHILD_DOWN from %s", pvt->children[i]->name);
+		pvt->state[i] = 0;
+		for (i = 0; i < pvt->child_count; i++) {
+			if (pvt->state[i])
+				break;
+		}
+		if (i == pvt->child_count) {
+			default_notify (this, event, data);
+		}
+	}
+	break;
+	case GF_EVENT_CHILD_UP:
+	{
+		for (i = 0; i < pvt->child_count; i++) {
+			if (data == pvt->children[i])
+				break;
+		}
+
+		gf_log (this->name, GF_LOG_DEBUG, "GF_EVENT_CHILD_UP from %s", pvt->children[i]->name);
+
+		pvt->state[i] = 1;
+
+		for (i = 0; i < pvt->child_count; i++) {
+			if (pvt->state[i])
+				upcnt++;
+		}
+
+		if (upcnt == 1) {
+			default_notify (this, event, data);
+		}
+	}
+	break;
+
+	default:
+	{
+		default_notify (this, event, data);
+	}
+	}
+
+	return 0;
+}
+
+int
+init (xlator_t *this)
+{
+	ha_private_t *pvt = NULL;
+	xlator_list_t *trav = NULL;
+	int count = 0, ret = 0;
+
+	if (!this->children) {
+		gf_log (this->name,GF_LOG_ERROR, 
+			"FATAL: ha should have one or more child defined");
+		return -1;
+	}
+
+	if (!this->parents) {
+		gf_log (this->name, GF_LOG_WARNING,
+			"dangling volume. check volfile ");
+	}
+  
+	trav = this->children;
+	pvt = CALLOC (1, sizeof (ha_private_t));
+
+	ret = dict_get_int32 (this->options, "preferred-subvolume", 
+			      &pvt->pref_subvol);
+	if (ret < 0) {
+		pvt->pref_subvol = -1;
+	}
+
+	trav = this->children;
+	while (trav) {
+		count++;
+		trav = trav->next;
+	}
+
+	pvt->child_count = count;
+	pvt->children = CALLOC (count, sizeof (xlator_t*));
+
+	trav = this->children;
+	count = 0;
+	while (trav) {
+		pvt->children[count] = trav->xlator;
+		count++;
+		trav = trav->next;
+	}
+
+	pvt->state = CALLOC (1, count);
+	this->private = pvt;
+	return 0;
+}
+
+void
+fini (xlator_t *this)
+{
+	ha_private_t *priv = NULL;
+	priv = this->private;
+	FREE (priv);
+	return;
+}
+
+
+struct xlator_fops fops = {
+	.lookup      = ha_lookup,
+	.stat        = ha_stat,
+	.readlink    = ha_readlink,
+	.mknod       = ha_mknod,
+	.mkdir       = ha_mkdir,
+	.unlink      = ha_unlink,
+	.rmdir       = ha_rmdir,
+	.symlink     = ha_symlink,
+	.rename      = ha_rename,
+	.link        = ha_link,
+	.chmod       = ha_chmod,
+	.chown       = ha_chown,
+	.truncate    = ha_truncate,
+	.utimens     = ha_utimens,
+	.create      = ha_create,
+	.open        = ha_open,
+	.readv       = ha_readv,
+	.writev      = ha_writev,
+	.statfs      = ha_statfs,
+	.flush       = ha_flush,
+	.fsync       = ha_fsync,
+	.setxattr    = ha_setxattr,
+	.getxattr    = ha_getxattr,
+	.removexattr = ha_removexattr,
+	.opendir     = ha_opendir,
+	.readdir     = ha_readdir,
+	.getdents    = ha_getdents,
+	.fsyncdir    = ha_fsyncdir,
+	.access      = ha_access,
+	.ftruncate   = ha_ftruncate,
+	.fstat       = ha_fstat,
+	.lk          = ha_lk,
+	.fchmod      = ha_fchmod,
+	.fchown      = ha_fchown,
+	.setdents    = ha_setdents,
+	.lookup_cbk  = ha_lookup_cbk,
+	.checksum    = ha_checksum,
+	.xattrop     = ha_xattrop,
+	.fxattrop    = ha_fxattrop
+};
+
+struct xlator_mops mops = {
+	.stats   = ha_stats,
+	.getspec = ha_getspec,
+};
+
+struct xlator_cbks cbks = {
+	.release    = ha_close,
+	.releasedir = ha_closedir,
+	.forget     = ha_forget,
+};
diff --git a/xlators/cluster/ha/src/ha.h b/xlators/cluster/ha/src/ha.h
new file mode 100644
index 000000000..77a04f165
--- /dev/null
+++ b/xlators/cluster/ha/src/ha.h
@@ -0,0 +1,59 @@
+/*
+  Copyright (c) 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 __HA_H_
+#define __HA_H_
+
+typedef struct {
+	call_stub_t *stub;
+	int32_t op_ret, op_errno;
+	int32_t active, tries, revalidate, revalidate_error;
+	int32_t call_count;
+	char *state, *pattern;
+	dict_t *dict;
+	loc_t *loc;
+	struct stat buf;
+	fd_t *fd;
+	inode_t *inode;
+	int32_t flags;
+	int32_t first_success;
+} ha_local_t;
+
+typedef struct {
+	char *state;
+	xlator_t **children;
+	int child_count, pref_subvol;
+} ha_private_t;
+
+typedef struct {
+	char *fdstate;
+	char *path;
+	gf_lock_t lock;
+	int active;
+} hafd_t;
+
+#define HA_ACTIVE_CHILD(this, local) (((ha_private_t *)this->private)->children[local->active])
+
+extern int ha_alloc_init_fd (call_frame_t *frame, fd_t *fd);
+
+extern int ha_handle_cbk (call_frame_t *frame, void *cookie, int op_ret, int op_errno) ;
+
+extern int ha_alloc_init_inode (call_frame_t *frame, inode_t *inode);
+
+#endif