drivers/staging/lustre/lustre/fld/fld_request.c - arm/linux - Git at Google

 /*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 only,
  * as published by the Free Software Foundation.
  *
  * This program 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 version 2 for more details (a copy is included
  * in the LICENSE file that accompanied this code).
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
  * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
 /*
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
  * Copyright (c) 2011, 2015, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
  * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * lustre/fld/fld_request.c
  *
  * FLD (Fids Location Database)
  *
  * Author: Yury Umanets <umka@clusterfs.com>
  */

 #define DEBUG_SUBSYSTEM S_FLD

 #include <linux/libcfs/libcfs.h>
 #include <linux/module.h>
 #include <asm/div64.h>

 #include <obd.h>
 #include <obd_class.h>
 #include <uapi/linux/lustre/lustre_ver.h>
 #include <obd_support.h>
 #include <lprocfs_status.h>

 #include <lustre_req_layout.h>
 #include <lustre_fld.h>
 #include <lustre_mdc.h>
 #include "fld_internal.h"

 static int fld_rrb_hash(struct lu_client_fld *fld, u64 seq)
 {
 	LASSERT(fld->lcf_count > 0);
 	return do_div(seq, fld->lcf_count);
 }

 static struct lu_fld_target *
 fld_rrb_scan(struct lu_client_fld *fld, u64 seq)
 {
 	struct lu_fld_target *target;
 	int hash;

 	/* Because almost all of special sequence located in MDT0,
 	 * it should go to index 0 directly, instead of calculating
 	 * hash again, and also if other MDTs is not being connected,
 	 * the fld lookup requests(for seq on MDT0) should not be
 	 * blocked because of other MDTs
 	 */
 	if (fid_seq_is_norm(seq))
 		hash = fld_rrb_hash(fld, seq);
 	else
 		hash = 0;

 again:
 	list_for_each_entry(target, &fld->lcf_targets, ft_chain) {
 		if (target->ft_idx == hash)
 			return target;
 	}

 	if (hash != 0) {
 		/* It is possible the remote target(MDT) are not connected to
 		 * with client yet, so we will refer this to MDT0, which should
 		 * be connected during mount
 		 */
 		hash = 0;
 		goto again;
 	}

 	CERROR("%s: Can't find target by hash %d (seq %#llx). Targets (%d):\n",
 	       fld->lcf_name, hash, seq, fld->lcf_count);

 	list_for_each_entry(target, &fld->lcf_targets, ft_chain) {
 		const char *srv_name = target->ft_srv ?
 			target->ft_srv->lsf_name : "<null>";
 		const char *exp_name = target->ft_exp ?
 			(char *)target->ft_exp->exp_obd->obd_uuid.uuid :
 			"<null>";

 		CERROR("  exp: 0x%p (%s), srv: 0x%p (%s), idx: %llu\n",
 		       target->ft_exp, exp_name, target->ft_srv,
 		       srv_name, target->ft_idx);
 	}

 	/*
 	 * If target is not found, there is logical error anyway, so here is
 	 * LBUG() to catch this situation.
 	 */
 	LBUG();
 	return NULL;
 }

 struct lu_fld_hash fld_hash[] = {
 	{
 		.fh_name = "RRB",
 		.fh_hash_func = fld_rrb_hash,
 		.fh_scan_func = fld_rrb_scan
 	},
 	{
 		NULL,
 	}
 };

 static struct lu_fld_target *
 fld_client_get_target(struct lu_client_fld *fld, u64 seq)
 {
 	struct lu_fld_target *target;

 	LASSERT(fld->lcf_hash);

 	spin_lock(&fld->lcf_lock);
 	target = fld->lcf_hash->fh_scan_func(fld, seq);
 	spin_unlock(&fld->lcf_lock);

 	if (target) {
 		CDEBUG(D_INFO, "%s: Found target (idx %llu) by seq %#llx\n",
 		       fld->lcf_name, target->ft_idx, seq);
 	}

 	return target;
 }

 /*
  * Add export to FLD. This is usually done by CMM and LMV as they are main users
  * of FLD module.
  */
 int fld_client_add_target(struct lu_client_fld *fld,
 			  struct lu_fld_target *tar)
 {
 	const char *name;
 	struct lu_fld_target *target, *tmp;

 	LASSERT(tar);
 	name = fld_target_name(tar);
 	LASSERT(name);
 	LASSERT(tar->ft_srv || tar->ft_exp);

 	CDEBUG(D_INFO, "%s: Adding target %s (idx %llu)\n",
 	       fld->lcf_name, name, tar->ft_idx);

 	target = kzalloc(sizeof(*target), GFP_NOFS);
 	if (!target)
 		return -ENOMEM;

 	spin_lock(&fld->lcf_lock);
 	list_for_each_entry(tmp, &fld->lcf_targets, ft_chain) {
 		if (tmp->ft_idx == tar->ft_idx) {
 			spin_unlock(&fld->lcf_lock);
 			kfree(target);
 			CERROR("Target %s exists in FLD and known as %s:#%llu\n",
 			       name, fld_target_name(tmp), tmp->ft_idx);
 			return -EEXIST;
 		}
 	}

 	target->ft_exp = tar->ft_exp;
 	if (target->ft_exp)
 		class_export_get(target->ft_exp);
 	target->ft_srv = tar->ft_srv;
 	target->ft_idx = tar->ft_idx;

 	list_add_tail(&target->ft_chain, &fld->lcf_targets);

 	fld->lcf_count++;
 	spin_unlock(&fld->lcf_lock);

 	return 0;
 }
 EXPORT_SYMBOL(fld_client_add_target);

 /* Remove export from FLD */
 int fld_client_del_target(struct lu_client_fld *fld, __u64 idx)
 {
 	struct lu_fld_target *target, *tmp;

 	spin_lock(&fld->lcf_lock);
 	list_for_each_entry_safe(target, tmp, &fld->lcf_targets, ft_chain) {
 		if (target->ft_idx == idx) {
 			fld->lcf_count--;
 			list_del(&target->ft_chain);
 			spin_unlock(&fld->lcf_lock);

 			if (target->ft_exp)
 				class_export_put(target->ft_exp);

 			kfree(target);
 			return 0;
 		}
 	}
 	spin_unlock(&fld->lcf_lock);
 	return -ENOENT;
 }

 static struct dentry *fld_debugfs_dir;

 static int fld_client_debugfs_init(struct lu_client_fld *fld)
 {
 	int rc;

 	fld->lcf_debugfs_entry = ldebugfs_register(fld->lcf_name,
 						   fld_debugfs_dir,
 						   NULL, NULL);

 	if (IS_ERR_OR_NULL(fld->lcf_debugfs_entry)) {
 		CERROR("%s: LdebugFS failed in fld-init\n", fld->lcf_name);
 		rc = fld->lcf_debugfs_entry ? PTR_ERR(fld->lcf_debugfs_entry)
 					    : -ENOMEM;
 		fld->lcf_debugfs_entry = NULL;
 		return rc;
 	}

 	rc = ldebugfs_add_vars(fld->lcf_debugfs_entry,
 			       fld_client_debugfs_list, fld);
 	if (rc) {
 		CERROR("%s: Can't init FLD debufs, rc %d\n", fld->lcf_name, rc);
 		goto out_cleanup;
 	}

 	return 0;

 out_cleanup:
 	fld_client_debugfs_fini(fld);
 	return rc;
 }

 void fld_client_debugfs_fini(struct lu_client_fld *fld)
 {
 	if (!IS_ERR_OR_NULL(fld->lcf_debugfs_entry))
 		ldebugfs_remove(&fld->lcf_debugfs_entry);
 }
 EXPORT_SYMBOL(fld_client_debugfs_fini);

 static inline int hash_is_sane(int hash)
 {
 	return (hash >= 0 && hash < ARRAY_SIZE(fld_hash));
 }

 int fld_client_init(struct lu_client_fld *fld,
 		    const char *prefix, int hash)
 {
 	int cache_size, cache_threshold;
 	int rc;

 	snprintf(fld->lcf_name, sizeof(fld->lcf_name),
 		 "cli-%s", prefix);

 	if (!hash_is_sane(hash)) {
 		CERROR("%s: Wrong hash function %#x\n",
 		       fld->lcf_name, hash);
 		return -EINVAL;
 	}

 	fld->lcf_count = 0;
 	spin_lock_init(&fld->lcf_lock);
 	fld->lcf_hash = &fld_hash[hash];
 	INIT_LIST_HEAD(&fld->lcf_targets);

 	cache_size = FLD_CLIENT_CACHE_SIZE /
 		sizeof(struct fld_cache_entry);

 	cache_threshold = cache_size *
 		FLD_CLIENT_CACHE_THRESHOLD / 100;

 	fld->lcf_cache = fld_cache_init(fld->lcf_name,
 					cache_size, cache_threshold);
 	if (IS_ERR(fld->lcf_cache)) {
 		rc = PTR_ERR(fld->lcf_cache);
 		fld->lcf_cache = NULL;
 		goto out;
 	}

 	rc = fld_client_debugfs_init(fld);
 	if (rc)
 		goto out;
 out:
 	if (rc)
 		fld_client_fini(fld);
 	else
 		CDEBUG(D_INFO, "%s: Using \"%s\" hash\n",
 		       fld->lcf_name, fld->lcf_hash->fh_name);
 	return rc;
 }
 EXPORT_SYMBOL(fld_client_init);

 void fld_client_fini(struct lu_client_fld *fld)
 {
 	struct lu_fld_target *target, *tmp;

 	spin_lock(&fld->lcf_lock);
 	list_for_each_entry_safe(target, tmp, &fld->lcf_targets, ft_chain) {
 		fld->lcf_count--;
 		list_del(&target->ft_chain);
 		if (target->ft_exp)
 			class_export_put(target->ft_exp);
 		kfree(target);
 	}
 	spin_unlock(&fld->lcf_lock);

 	if (fld->lcf_cache) {
 		if (!IS_ERR(fld->lcf_cache))
 			fld_cache_fini(fld->lcf_cache);
 		fld->lcf_cache = NULL;
 	}
 }
 EXPORT_SYMBOL(fld_client_fini);

 int fld_client_rpc(struct obd_export *exp,
 		   struct lu_seq_range *range, __u32 fld_op,
 		   struct ptlrpc_request **reqp)
 {
 	struct ptlrpc_request *req = NULL;
 	struct lu_seq_range   *prange;
 	__u32		 *op;
 	int		    rc = 0;
 	struct obd_import     *imp;

 	LASSERT(exp);

 	imp = class_exp2cliimp(exp);
 	switch (fld_op) {
 	case FLD_QUERY:
 		req = ptlrpc_request_alloc_pack(imp, &RQF_FLD_QUERY,
 						LUSTRE_MDS_VERSION, FLD_QUERY);
 		if (!req)
 			return -ENOMEM;

 		/*
 		 * XXX: only needed when talking to old server(< 2.6), it should
 		 * be removed when < 2.6 server is not supported
 		 */
 		op = req_capsule_client_get(&req->rq_pill, &RMF_FLD_OPC);
 		*op = FLD_LOOKUP;

 		if (imp->imp_connect_flags_orig & OBD_CONNECT_MDS_MDS)
 			req->rq_allow_replay = 1;
 		break;
 	case FLD_READ:
 		req = ptlrpc_request_alloc_pack(imp, &RQF_FLD_READ,
 						LUSTRE_MDS_VERSION, FLD_READ);
 		if (!req)
 			return -ENOMEM;

 		req_capsule_set_size(&req->rq_pill, &RMF_GENERIC_DATA,
 				     RCL_SERVER, PAGE_SIZE);
 		break;
 	default:
 		rc = -EINVAL;
 		break;
 	}
 	if (rc)
 		return rc;

 	prange = req_capsule_client_get(&req->rq_pill, &RMF_FLD_MDFLD);
 	*prange = *range;
 	ptlrpc_request_set_replen(req);
 	req->rq_request_portal = FLD_REQUEST_PORTAL;
 	req->rq_reply_portal = MDC_REPLY_PORTAL;
 	ptlrpc_at_set_req_timeout(req);

 	obd_get_request_slot(&exp->exp_obd->u.cli);
 	rc = ptlrpc_queue_wait(req);
 	obd_put_request_slot(&exp->exp_obd->u.cli);
 	if (rc)
 		goto out_req;

 	if (fld_op == FLD_QUERY) {
 		prange = req_capsule_server_get(&req->rq_pill, &RMF_FLD_MDFLD);
 		if (!prange) {
 			rc = -EFAULT;
 			goto out_req;
 		}
 		*range = *prange;
 	}

 out_req:
 	if (rc || !reqp) {
 		ptlrpc_req_finished(req);
 		req = NULL;
 	}

 	if (reqp)
 		*reqp = req;

 	return rc;
 }

 int fld_client_lookup(struct lu_client_fld *fld, u64 seq, u32 *mds,
 		      __u32 flags, const struct lu_env *env)
 {
 	struct lu_seq_range res = { 0 };
 	struct lu_fld_target *target;
 	int rc;

 	rc = fld_cache_lookup(fld->lcf_cache, seq, &res);
 	if (rc == 0) {
 		*mds = res.lsr_index;
 		return 0;
 	}

 	/* Can not find it in the cache */
 	target = fld_client_get_target(fld, seq);
 	LASSERT(target);

 	CDEBUG(D_INFO, "%s: Lookup fld entry (seq: %#llx) on target %s (idx %llu)\n",
 	       fld->lcf_name, seq, fld_target_name(target), target->ft_idx);

 	res.lsr_start = seq;
 	fld_range_set_type(&res, flags);
 	rc = fld_client_rpc(target->ft_exp, &res, FLD_QUERY, NULL);

 	if (rc == 0) {
 		*mds = res.lsr_index;

 		fld_cache_insert(fld->lcf_cache, &res);
 	}
 	return rc;
 }
 EXPORT_SYMBOL(fld_client_lookup);

 void fld_client_flush(struct lu_client_fld *fld)
 {
 	fld_cache_flush(fld->lcf_cache);
 }

 static int __init fld_init(void)
 {
 	fld_debugfs_dir = ldebugfs_register(LUSTRE_FLD_NAME,
 					    debugfs_lustre_root,
 					    NULL, NULL);
 	return PTR_ERR_OR_ZERO(fld_debugfs_dir);
 }

 static void __exit fld_exit(void)
 {
 	if (!IS_ERR_OR_NULL(fld_debugfs_dir))
 		ldebugfs_remove(&fld_debugfs_dir);
 }

 MODULE_AUTHOR("OpenSFS, Inc. <http://www.lustre.org/>");
 MODULE_DESCRIPTION("Lustre FID Location Database");
 MODULE_VERSION(LUSTRE_VERSION_STRING);
 MODULE_LICENSE("GPL");

 module_init(fld_init)
 module_exit(fld_exit)
	/*
	* GPL HEADER START
	*
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 only,
	* as published by the Free Software Foundation.
	*
	* This program 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 version 2 for more details (a copy is included
	* in the LICENSE file that accompanied this code).
	*
	* You should have received a copy of the GNU General Public License
	* version 2 along with this program; If not, see
	* http://www.gnu.org/licenses/gpl-2.0.html
	*
	* GPL HEADER END
	*/
	/*
	* Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
	* Use is subject to license terms.
	*
	* Copyright (c) 2011, 2015, Intel Corporation.
	*/
	/*
	* This file is part of Lustre, http://www.lustre.org/
	* Lustre is a trademark of Sun Microsystems, Inc.
	*
	* lustre/fld/fld_request.c
	*
	* FLD (Fids Location Database)
	*
	* Author: Yury Umanets <umka@clusterfs.com>
	*/

	#define DEBUG_SUBSYSTEM S_FLD

	#include <linux/libcfs/libcfs.h>
	#include <linux/module.h>
	#include <asm/div64.h>

	#include <obd.h>
	#include <obd_class.h>
	#include <uapi/linux/lustre/lustre_ver.h>
	#include <obd_support.h>
	#include <lprocfs_status.h>

	#include <lustre_req_layout.h>
	#include <lustre_fld.h>
	#include <lustre_mdc.h>
	#include "fld_internal.h"

	static int fld_rrb_hash(struct lu_client_fld *fld, u64 seq)
	{
	LASSERT(fld->lcf_count > 0);
	return do_div(seq, fld->lcf_count);
	}

	static struct lu_fld_target *
	fld_rrb_scan(struct lu_client_fld *fld, u64 seq)
	{
	struct lu_fld_target *target;
	int hash;

	/* Because almost all of special sequence located in MDT0,
	* it should go to index 0 directly, instead of calculating
	* hash again, and also if other MDTs is not being connected,
	* the fld lookup requests(for seq on MDT0) should not be
	* blocked because of other MDTs
	*/
	if (fid_seq_is_norm(seq))
	hash = fld_rrb_hash(fld, seq);
	else
	hash = 0;

	again:
	list_for_each_entry(target, &fld->lcf_targets, ft_chain) {
	if (target->ft_idx == hash)
	return target;
	}

	if (hash != 0) {
	/* It is possible the remote target(MDT) are not connected to
	* with client yet, so we will refer this to MDT0, which should
	* be connected during mount
	*/
	hash = 0;
	goto again;
	}

	CERROR("%s: Can't find target by hash %d (seq %#llx). Targets (%d):\n",
	fld->lcf_name, hash, seq, fld->lcf_count);

	list_for_each_entry(target, &fld->lcf_targets, ft_chain) {
	const char *srv_name = target->ft_srv ?
	target->ft_srv->lsf_name : "<null>";
	const char *exp_name = target->ft_exp ?
	(char *)target->ft_exp->exp_obd->obd_uuid.uuid :
	"<null>";

	CERROR(" exp: 0x%p (%s), srv: 0x%p (%s), idx: %llu\n",
	target->ft_exp, exp_name, target->ft_srv,
	srv_name, target->ft_idx);
	}

	/*
	* If target is not found, there is logical error anyway, so here is
	* LBUG() to catch this situation.
	*/
	LBUG();
	return NULL;
	}

	struct lu_fld_hash fld_hash[] = {
	{
	.fh_name = "RRB",
	.fh_hash_func = fld_rrb_hash,
	.fh_scan_func = fld_rrb_scan
	},
	{
	NULL,
	}
	};

	static struct lu_fld_target *
	fld_client_get_target(struct lu_client_fld *fld, u64 seq)
	{
	struct lu_fld_target *target;

	LASSERT(fld->lcf_hash);

	spin_lock(&fld->lcf_lock);
	target = fld->lcf_hash->fh_scan_func(fld, seq);
	spin_unlock(&fld->lcf_lock);

	if (target) {
	CDEBUG(D_INFO, "%s: Found target (idx %llu) by seq %#llx\n",
	fld->lcf_name, target->ft_idx, seq);
	}

	return target;
	}

	/*
	* Add export to FLD. This is usually done by CMM and LMV as they are main users
	* of FLD module.
	*/
	int fld_client_add_target(struct lu_client_fld *fld,
	struct lu_fld_target *tar)
	{
	const char *name;
	struct lu_fld_target target, tmp;

	LASSERT(tar);
	name = fld_target_name(tar);
	LASSERT(name);
	LASSERT(tar->ft_srv \|\| tar->ft_exp);

	CDEBUG(D_INFO, "%s: Adding target %s (idx %llu)\n",
	fld->lcf_name, name, tar->ft_idx);

	target = kzalloc(sizeof(*target), GFP_NOFS);
	if (!target)
	return -ENOMEM;

	spin_lock(&fld->lcf_lock);
	list_for_each_entry(tmp, &fld->lcf_targets, ft_chain) {
	if (tmp->ft_idx == tar->ft_idx) {
	spin_unlock(&fld->lcf_lock);
	kfree(target);
	CERROR("Target %s exists in FLD and known as %s:#%llu\n",
	name, fld_target_name(tmp), tmp->ft_idx);
	return -EEXIST;
	}
	}

	target->ft_exp = tar->ft_exp;
	if (target->ft_exp)
	class_export_get(target->ft_exp);
	target->ft_srv = tar->ft_srv;
	target->ft_idx = tar->ft_idx;

	list_add_tail(&target->ft_chain, &fld->lcf_targets);

	fld->lcf_count++;
	spin_unlock(&fld->lcf_lock);

	return 0;
	}
	EXPORT_SYMBOL(fld_client_add_target);

	/* Remove export from FLD */
	int fld_client_del_target(struct lu_client_fld *fld, __u64 idx)
	{
	struct lu_fld_target target, tmp;

	spin_lock(&fld->lcf_lock);
	list_for_each_entry_safe(target, tmp, &fld->lcf_targets, ft_chain) {
	if (target->ft_idx == idx) {
	fld->lcf_count--;
	list_del(&target->ft_chain);
	spin_unlock(&fld->lcf_lock);

	if (target->ft_exp)
	class_export_put(target->ft_exp);

	kfree(target);
	return 0;
	}
	}
	spin_unlock(&fld->lcf_lock);
	return -ENOENT;
	}

	static struct dentry *fld_debugfs_dir;

	static int fld_client_debugfs_init(struct lu_client_fld *fld)
	{
	int rc;

	fld->lcf_debugfs_entry = ldebugfs_register(fld->lcf_name,
	fld_debugfs_dir,
	NULL, NULL);

	if (IS_ERR_OR_NULL(fld->lcf_debugfs_entry)) {
	CERROR("%s: LdebugFS failed in fld-init\n", fld->lcf_name);
	rc = fld->lcf_debugfs_entry ? PTR_ERR(fld->lcf_debugfs_entry)
	: -ENOMEM;
	fld->lcf_debugfs_entry = NULL;
	return rc;
	}

	rc = ldebugfs_add_vars(fld->lcf_debugfs_entry,
	fld_client_debugfs_list, fld);
	if (rc) {
	CERROR("%s: Can't init FLD debufs, rc %d\n", fld->lcf_name, rc);
	goto out_cleanup;
	}

	return 0;

	out_cleanup:
	fld_client_debugfs_fini(fld);
	return rc;
	}

	void fld_client_debugfs_fini(struct lu_client_fld *fld)
	{
	if (!IS_ERR_OR_NULL(fld->lcf_debugfs_entry))
	ldebugfs_remove(&fld->lcf_debugfs_entry);
	}
	EXPORT_SYMBOL(fld_client_debugfs_fini);

	static inline int hash_is_sane(int hash)
	{
	return (hash >= 0 && hash < ARRAY_SIZE(fld_hash));
	}

	int fld_client_init(struct lu_client_fld *fld,
	const char *prefix, int hash)
	{
	int cache_size, cache_threshold;
	int rc;

	snprintf(fld->lcf_name, sizeof(fld->lcf_name),
	"cli-%s", prefix);

	if (!hash_is_sane(hash)) {
	CERROR("%s: Wrong hash function %#x\n",
	fld->lcf_name, hash);
	return -EINVAL;
	}

	fld->lcf_count = 0;
	spin_lock_init(&fld->lcf_lock);
	fld->lcf_hash = &fld_hash[hash];
	INIT_LIST_HEAD(&fld->lcf_targets);

	cache_size = FLD_CLIENT_CACHE_SIZE /
	sizeof(struct fld_cache_entry);

	cache_threshold = cache_size *
	FLD_CLIENT_CACHE_THRESHOLD / 100;

	fld->lcf_cache = fld_cache_init(fld->lcf_name,
	cache_size, cache_threshold);
	if (IS_ERR(fld->lcf_cache)) {
	rc = PTR_ERR(fld->lcf_cache);
	fld->lcf_cache = NULL;
	goto out;
	}

	rc = fld_client_debugfs_init(fld);
	if (rc)
	goto out;
	out:
	if (rc)
	fld_client_fini(fld);
	else
	CDEBUG(D_INFO, "%s: Using \"%s\" hash\n",
	fld->lcf_name, fld->lcf_hash->fh_name);
	return rc;
	}
	EXPORT_SYMBOL(fld_client_init);

	void fld_client_fini(struct lu_client_fld *fld)
	{
	struct lu_fld_target target, tmp;

	spin_lock(&fld->lcf_lock);
	list_for_each_entry_safe(target, tmp, &fld->lcf_targets, ft_chain) {
	fld->lcf_count--;
	list_del(&target->ft_chain);
	if (target->ft_exp)
	class_export_put(target->ft_exp);
	kfree(target);
	}
	spin_unlock(&fld->lcf_lock);

	if (fld->lcf_cache) {
	if (!IS_ERR(fld->lcf_cache))
	fld_cache_fini(fld->lcf_cache);
	fld->lcf_cache = NULL;
	}
	}
	EXPORT_SYMBOL(fld_client_fini);

	int fld_client_rpc(struct obd_export *exp,
	struct lu_seq_range *range, __u32 fld_op,
	struct ptlrpc_request **reqp)
	{
	struct ptlrpc_request *req = NULL;
	struct lu_seq_range *prange;
	__u32 *op;
	int rc = 0;
	struct obd_import *imp;

	LASSERT(exp);

	imp = class_exp2cliimp(exp);
	switch (fld_op) {
	case FLD_QUERY:
	req = ptlrpc_request_alloc_pack(imp, &RQF_FLD_QUERY,
	LUSTRE_MDS_VERSION, FLD_QUERY);
	if (!req)
	return -ENOMEM;

	/*
	* XXX: only needed when talking to old server(< 2.6), it should
	* be removed when < 2.6 server is not supported
	*/
	op = req_capsule_client_get(&req->rq_pill, &RMF_FLD_OPC);
	*op = FLD_LOOKUP;

	if (imp->imp_connect_flags_orig & OBD_CONNECT_MDS_MDS)
	req->rq_allow_replay = 1;
	break;
	case FLD_READ:
	req = ptlrpc_request_alloc_pack(imp, &RQF_FLD_READ,
	LUSTRE_MDS_VERSION, FLD_READ);
	if (!req)
	return -ENOMEM;

	req_capsule_set_size(&req->rq_pill, &RMF_GENERIC_DATA,
	RCL_SERVER, PAGE_SIZE);
	break;
	default:
	rc = -EINVAL;
	break;
	}
	if (rc)
	return rc;

	prange = req_capsule_client_get(&req->rq_pill, &RMF_FLD_MDFLD);
	prange = range;
	ptlrpc_request_set_replen(req);
	req->rq_request_portal = FLD_REQUEST_PORTAL;
	req->rq_reply_portal = MDC_REPLY_PORTAL;
	ptlrpc_at_set_req_timeout(req);

	obd_get_request_slot(&exp->exp_obd->u.cli);
	rc = ptlrpc_queue_wait(req);
	obd_put_request_slot(&exp->exp_obd->u.cli);
	if (rc)
	goto out_req;

	if (fld_op == FLD_QUERY) {
	prange = req_capsule_server_get(&req->rq_pill, &RMF_FLD_MDFLD);
	if (!prange) {
	rc = -EFAULT;
	goto out_req;
	}
	range = prange;
	}

	out_req:
	if (rc \|\| !reqp) {
	ptlrpc_req_finished(req);
	req = NULL;
	}

	if (reqp)
	*reqp = req;

	return rc;
	}

	int fld_client_lookup(struct lu_client_fld fld, u64 seq, u32 mds,
	__u32 flags, const struct lu_env *env)
	{
	struct lu_seq_range res = { 0 };
	struct lu_fld_target *target;
	int rc;

	rc = fld_cache_lookup(fld->lcf_cache, seq, &res);
	if (rc == 0) {
	*mds = res.lsr_index;
	return 0;
	}

	/* Can not find it in the cache */
	target = fld_client_get_target(fld, seq);
	LASSERT(target);

	CDEBUG(D_INFO, "%s: Lookup fld entry (seq: %#llx) on target %s (idx %llu)\n",
	fld->lcf_name, seq, fld_target_name(target), target->ft_idx);

	res.lsr_start = seq;
	fld_range_set_type(&res, flags);
	rc = fld_client_rpc(target->ft_exp, &res, FLD_QUERY, NULL);

	if (rc == 0) {
	*mds = res.lsr_index;

	fld_cache_insert(fld->lcf_cache, &res);
	}
	return rc;
	}
	EXPORT_SYMBOL(fld_client_lookup);

	void fld_client_flush(struct lu_client_fld *fld)
	{
	fld_cache_flush(fld->lcf_cache);
	}

	static int __init fld_init(void)
	{
	fld_debugfs_dir = ldebugfs_register(LUSTRE_FLD_NAME,
	debugfs_lustre_root,
	NULL, NULL);
	return PTR_ERR_OR_ZERO(fld_debugfs_dir);
	}

	static void __exit fld_exit(void)
	{
	if (!IS_ERR_OR_NULL(fld_debugfs_dir))
	ldebugfs_remove(&fld_debugfs_dir);
	}

	MODULE_AUTHOR("OpenSFS, Inc. <http://www.lustre.org/>");
	MODULE_DESCRIPTION("Lustre FID Location Database");
	MODULE_VERSION(LUSTRE_VERSION_STRING);
	MODULE_LICENSE("GPL");

	module_init(fld_init)
	module_exit(fld_exit)