/*
 * 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) 2001, 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.
 */

#define DEBUG_SUBSYSTEM S_MDC

# include <linux/module.h>
# include <linux/pagemap.h>
# include <linux/miscdevice.h>
# include <linux/init.h>
# include <linux/utsname.h>

#include "../include/lustre_acl.h"
#include "../include/lustre/lustre_ioctl.h"
#include "../include/obd_class.h"
#include "../include/lustre_lmv.h"
#include "../include/lustre_fid.h"
#include "../include/lprocfs_status.h"
#include "../include/lustre_param.h"
#include "../include/lustre_log.h"
#include "../include/lustre_kernelcomm.h"

#include "mdc_internal.h"

#define REQUEST_MINOR 244

static int mdc_cleanup(struct obd_device *obd);

static inline int mdc_queue_wait(struct ptlrpc_request *req)
{
	struct client_obd *cli = &req->rq_import->imp_obd->u.cli;
	int rc;

	/* obd_get_request_slot() ensures that this client has no more
	 * than cl_max_rpcs_in_flight RPCs simultaneously inf light
	 * against an MDT.
	 */
	rc = obd_get_request_slot(cli);
	if (rc != 0)
		return rc;

	rc = ptlrpc_queue_wait(req);
	obd_put_request_slot(cli);

	return rc;
}

static int mdc_getstatus(struct obd_export *exp, struct lu_fid *rootfid)
{
	struct ptlrpc_request *req;
	struct mdt_body       *body;
	int		    rc;

	req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
					&RQF_MDS_GETSTATUS,
					LUSTRE_MDS_VERSION, MDS_GETSTATUS);
	if (!req)
		return -ENOMEM;

	mdc_pack_body(req, NULL, 0, 0, -1, 0);
	req->rq_send_state = LUSTRE_IMP_FULL;

	ptlrpc_request_set_replen(req);

	rc = ptlrpc_queue_wait(req);
	if (rc)
		goto out;

	body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
	if (!body) {
		rc = -EPROTO;
		goto out;
	}

	*rootfid = body->mbo_fid1;
	CDEBUG(D_NET,
	       "root fid="DFID", last_committed=%llu\n",
	       PFID(rootfid),
	       lustre_msg_get_last_committed(req->rq_repmsg));
out:
	ptlrpc_req_finished(req);
	return rc;
}

/*
 * This function now is known to always saying that it will receive 4 buffers
 * from server. Even for cases when acl_size and md_size is zero, RPC header
 * will contain 4 fields and RPC itself will contain zero size fields. This is
 * because mdt_getattr*() _always_ returns 4 fields, but if acl is not needed
 * and thus zero, it shrinks it, making zero size. The same story about
 * md_size. And this is course of problem when client waits for smaller number
 * of fields. This issue will be fixed later when client gets aware of RPC
 * layouts.  --umka
 */
static int mdc_getattr_common(struct obd_export *exp,
			      struct ptlrpc_request *req)
{
	struct req_capsule *pill = &req->rq_pill;
	struct mdt_body    *body;
	void	       *eadata;
	int		 rc;

	/* Request message already built. */
	rc = ptlrpc_queue_wait(req);
	if (rc != 0)
		return rc;

	/* sanity check for the reply */
	body = req_capsule_server_get(pill, &RMF_MDT_BODY);
	if (!body)
		return -EPROTO;

	CDEBUG(D_NET, "mode: %o\n", body->mbo_mode);

	mdc_update_max_ea_from_body(exp, body);
	if (body->mbo_eadatasize != 0) {
		eadata = req_capsule_server_sized_get(pill, &RMF_MDT_MD,
						      body->mbo_eadatasize);
		if (!eadata)
			return -EPROTO;
	}

	return 0;
}

static int mdc_getattr(struct obd_export *exp, struct md_op_data *op_data,
		       struct ptlrpc_request **request)
{
	struct ptlrpc_request *req;
	int		    rc;

	/* Single MDS without an LMV case */
	if (op_data->op_flags & MF_GET_MDT_IDX) {
		op_data->op_mds = 0;
		return 0;
	}
	*request = NULL;
	req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_MDS_GETATTR);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_GETATTR);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, &op_data->op_fid1, op_data->op_valid,
		      op_data->op_mode, -1, 0);

	req_capsule_set_size(&req->rq_pill, &RMF_MDT_MD, RCL_SERVER,
			     op_data->op_mode);
	ptlrpc_request_set_replen(req);

	rc = mdc_getattr_common(exp, req);
	if (rc)
		ptlrpc_req_finished(req);
	else
		*request = req;
	return rc;
}

static int mdc_getattr_name(struct obd_export *exp, struct md_op_data *op_data,
			    struct ptlrpc_request **request)
{
	struct ptlrpc_request *req;
	int		    rc;

	*request = NULL;
	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
				   &RQF_MDS_GETATTR_NAME);
	if (!req)
		return -ENOMEM;

	req_capsule_set_size(&req->rq_pill, &RMF_NAME, RCL_CLIENT,
			     op_data->op_namelen + 1);

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_GETATTR_NAME);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, &op_data->op_fid1, op_data->op_valid,
		      op_data->op_mode, op_data->op_suppgids[0], 0);

	if (op_data->op_name) {
		char *name = req_capsule_client_get(&req->rq_pill, &RMF_NAME);

		LASSERT(strnlen(op_data->op_name, op_data->op_namelen) ==
				op_data->op_namelen);
		memcpy(name, op_data->op_name, op_data->op_namelen);
	}

	req_capsule_set_size(&req->rq_pill, &RMF_MDT_MD, RCL_SERVER,
			     op_data->op_mode);
	ptlrpc_request_set_replen(req);

	rc = mdc_getattr_common(exp, req);
	if (rc)
		ptlrpc_req_finished(req);
	else
		*request = req;
	return rc;
}

static int mdc_xattr_common(struct obd_export *exp,
			    const struct req_format *fmt,
			    const struct lu_fid *fid,
			    int opcode, u64 valid,
			    const char *xattr_name, const char *input,
			    int input_size, int output_size, int flags,
			    __u32 suppgid, struct ptlrpc_request **request)
{
	struct ptlrpc_request *req;
	int   xattr_namelen = 0;
	char *tmp;
	int   rc;

	*request = NULL;
	req = ptlrpc_request_alloc(class_exp2cliimp(exp), fmt);
	if (!req)
		return -ENOMEM;

	if (xattr_name) {
		xattr_namelen = strlen(xattr_name) + 1;
		req_capsule_set_size(&req->rq_pill, &RMF_NAME, RCL_CLIENT,
				     xattr_namelen);
	}
	if (input_size) {
		LASSERT(input);
		req_capsule_set_size(&req->rq_pill, &RMF_EADATA, RCL_CLIENT,
				     input_size);
	}

	/* Flush local XATTR locks to get rid of a possible cancel RPC */
	if (opcode == MDS_REINT && fid_is_sane(fid) &&
	    exp->exp_connect_data.ocd_ibits_known & MDS_INODELOCK_XATTR) {
		LIST_HEAD(cancels);
		int count;

		/* Without that packing would fail */
		if (input_size == 0)
			req_capsule_set_size(&req->rq_pill, &RMF_EADATA,
					     RCL_CLIENT, 0);

		count = mdc_resource_get_unused(exp, fid,
						&cancels, LCK_EX,
						MDS_INODELOCK_XATTR);

		rc = mdc_prep_elc_req(exp, req, MDS_REINT, &cancels, count);
		if (rc) {
			ptlrpc_request_free(req);
			return rc;
		}
	} else {
		rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, opcode);
		if (rc) {
			ptlrpc_request_free(req);
			return rc;
		}
	}

	if (opcode == MDS_REINT) {
		struct mdt_rec_setxattr *rec;

		CLASSERT(sizeof(struct mdt_rec_setxattr) ==
			 sizeof(struct mdt_rec_reint));
		rec = req_capsule_client_get(&req->rq_pill, &RMF_REC_REINT);
		rec->sx_opcode = REINT_SETXATTR;
		rec->sx_fsuid  = from_kuid(&init_user_ns, current_fsuid());
		rec->sx_fsgid  = from_kgid(&init_user_ns, current_fsgid());
		rec->sx_cap    = cfs_curproc_cap_pack();
		rec->sx_suppgid1 = suppgid;
		rec->sx_suppgid2 = -1;
		rec->sx_fid    = *fid;
		rec->sx_valid  = valid | OBD_MD_FLCTIME;
		rec->sx_time   = ktime_get_real_seconds();
		rec->sx_size   = output_size;
		rec->sx_flags  = flags;

	} else {
		mdc_pack_body(req, fid, valid, output_size, suppgid, flags);
	}

	if (xattr_name) {
		tmp = req_capsule_client_get(&req->rq_pill, &RMF_NAME);
		memcpy(tmp, xattr_name, xattr_namelen);
	}
	if (input_size) {
		tmp = req_capsule_client_get(&req->rq_pill, &RMF_EADATA);
		memcpy(tmp, input, input_size);
	}

	if (req_capsule_has_field(&req->rq_pill, &RMF_EADATA, RCL_SERVER))
		req_capsule_set_size(&req->rq_pill, &RMF_EADATA,
				     RCL_SERVER, output_size);
	ptlrpc_request_set_replen(req);

	/* make rpc */
	if (opcode == MDS_REINT)
		mdc_get_rpc_lock(exp->exp_obd->u.cli.cl_rpc_lock, NULL);

	rc = ptlrpc_queue_wait(req);

	if (opcode == MDS_REINT)
		mdc_put_rpc_lock(exp->exp_obd->u.cli.cl_rpc_lock, NULL);

	if (rc)
		ptlrpc_req_finished(req);
	else
		*request = req;
	return rc;
}

static int mdc_setxattr(struct obd_export *exp, const struct lu_fid *fid,
			u64 valid, const char *xattr_name,
			const char *input, int input_size, int output_size,
			int flags, __u32 suppgid,
			struct ptlrpc_request **request)
{
	return mdc_xattr_common(exp, &RQF_MDS_REINT_SETXATTR,
				fid, MDS_REINT, valid, xattr_name,
				input, input_size, output_size, flags,
				suppgid, request);
}

static int mdc_getxattr(struct obd_export *exp, const struct lu_fid *fid,
			u64 valid, const char *xattr_name,
			const char *input, int input_size, int output_size,
			int flags, struct ptlrpc_request **request)
{
	return mdc_xattr_common(exp, &RQF_MDS_GETXATTR,
				fid, MDS_GETXATTR, valid, xattr_name,
				input, input_size, output_size, flags,
				-1, request);
}

#ifdef CONFIG_FS_POSIX_ACL
static int mdc_unpack_acl(struct ptlrpc_request *req, struct lustre_md *md)
{
	struct req_capsule     *pill = &req->rq_pill;
	struct mdt_body	*body = md->body;
	struct posix_acl       *acl;
	void		   *buf;
	int		     rc;

	if (!body->mbo_aclsize)
		return 0;

	buf = req_capsule_server_sized_get(pill, &RMF_ACL, body->mbo_aclsize);

	if (!buf)
		return -EPROTO;

	acl = posix_acl_from_xattr(&init_user_ns, buf, body->mbo_aclsize);
	if (!acl)
		return 0;

	if (IS_ERR(acl)) {
		rc = PTR_ERR(acl);
		CERROR("convert xattr to acl: %d\n", rc);
		return rc;
	}

	rc = posix_acl_valid(&init_user_ns, acl);
	if (rc) {
		CERROR("validate acl: %d\n", rc);
		posix_acl_release(acl);
		return rc;
	}

	md->posix_acl = acl;
	return 0;
}
#else
#define mdc_unpack_acl(req, md) 0
#endif

static int mdc_get_lustre_md(struct obd_export *exp,
			     struct ptlrpc_request *req,
			     struct obd_export *dt_exp,
			     struct obd_export *md_exp,
			     struct lustre_md *md)
{
	struct req_capsule *pill = &req->rq_pill;
	int rc;

	LASSERT(md);
	memset(md, 0, sizeof(*md));

	md->body = req_capsule_server_get(pill, &RMF_MDT_BODY);

	if (md->body->mbo_valid & OBD_MD_FLEASIZE) {
		int lmmsize;
		struct lov_mds_md *lmm;

		if (!S_ISREG(md->body->mbo_mode)) {
			CDEBUG(D_INFO,
			       "OBD_MD_FLEASIZE set, should be a regular file, but is not\n");
			rc = -EPROTO;
			goto out;
		}

		if (md->body->mbo_eadatasize == 0) {
			CDEBUG(D_INFO,
			       "OBD_MD_FLEASIZE set, but eadatasize 0\n");
			rc = -EPROTO;
			goto out;
		}
		lmmsize = md->body->mbo_eadatasize;
		lmm = req_capsule_server_sized_get(pill, &RMF_MDT_MD, lmmsize);
		if (!lmm) {
			rc = -EPROTO;
			goto out;
		}

		rc = obd_unpackmd(dt_exp, &md->lsm, lmm, lmmsize);
		if (rc < 0)
			goto out;

		if (rc < (typeof(rc))sizeof(*md->lsm)) {
			CDEBUG(D_INFO,
			       "lsm size too small: rc < sizeof (*md->lsm) (%d < %d)\n",
			       rc, (int)sizeof(*md->lsm));
			rc = -EPROTO;
			goto out;
		}

	} else if (md->body->mbo_valid & OBD_MD_FLDIREA) {
		int lmvsize;
		struct lov_mds_md *lmv;

		if (!S_ISDIR(md->body->mbo_mode)) {
			CDEBUG(D_INFO,
			       "OBD_MD_FLDIREA set, should be a directory, but is not\n");
			rc = -EPROTO;
			goto out;
		}

		if (md->body->mbo_eadatasize == 0) {
			CDEBUG(D_INFO,
			       "OBD_MD_FLDIREA is set, but eadatasize 0\n");
			return -EPROTO;
		}
		if (md->body->mbo_valid & OBD_MD_MEA) {
			lmvsize = md->body->mbo_eadatasize;
			lmv = req_capsule_server_sized_get(pill, &RMF_MDT_MD,
							   lmvsize);
			if (!lmv) {
				rc = -EPROTO;
				goto out;
			}

			rc = obd_unpackmd(md_exp, (void *)&md->lmv, lmv,
					  lmvsize);
			if (rc < 0)
				goto out;

			if (rc < (typeof(rc))sizeof(*md->lmv)) {
				CDEBUG(D_INFO,
				       "size too small: rc < sizeof(*md->lmv) (%d < %d)\n",
					rc, (int)sizeof(*md->lmv));
				rc = -EPROTO;
				goto out;
			}
		}
	}
	rc = 0;

	if (md->body->mbo_valid & OBD_MD_FLACL) {
		/* for ACL, it's possible that FLACL is set but aclsize is zero.
		 * only when aclsize != 0 there's an actual segment for ACL
		 * in reply buffer.
		 */
		if (md->body->mbo_aclsize) {
			rc = mdc_unpack_acl(req, md);
			if (rc)
				goto out;
#ifdef CONFIG_FS_POSIX_ACL
		} else {
			md->posix_acl = NULL;
#endif
		}
	}

out:
	if (rc) {
#ifdef CONFIG_FS_POSIX_ACL
		posix_acl_release(md->posix_acl);
#endif
		if (md->lsm)
			obd_free_memmd(dt_exp, &md->lsm);
	}
	return rc;
}

static int mdc_free_lustre_md(struct obd_export *exp, struct lustre_md *md)
{
	return 0;
}

/**
 * Handles both OPEN and SETATTR RPCs for OPEN-CLOSE and SETATTR-DONE_WRITING
 * RPC chains.
 */
void mdc_replay_open(struct ptlrpc_request *req)
{
	struct md_open_data *mod = req->rq_cb_data;
	struct ptlrpc_request *close_req;
	struct obd_client_handle *och;
	struct lustre_handle old;
	struct mdt_body *body;

	if (!mod) {
		DEBUG_REQ(D_ERROR, req,
			  "Can't properly replay without open data.");
		return;
	}

	body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);

	och = mod->mod_och;
	if (och) {
		struct lustre_handle *file_fh;

		LASSERT(och->och_magic == OBD_CLIENT_HANDLE_MAGIC);

		file_fh = &och->och_fh;
		CDEBUG(D_HA, "updating handle from %#llx to %#llx\n",
		       file_fh->cookie, body->mbo_handle.cookie);
		old = *file_fh;
		*file_fh = body->mbo_handle;
	}
	close_req = mod->mod_close_req;
	if (close_req) {
		__u32 opc = lustre_msg_get_opc(close_req->rq_reqmsg);
		struct mdt_ioepoch *epoch;

		LASSERT(opc == MDS_CLOSE || opc == MDS_DONE_WRITING);
		epoch = req_capsule_client_get(&close_req->rq_pill,
					       &RMF_MDT_EPOCH);
		LASSERT(epoch);

		if (och)
			LASSERT(!memcmp(&old, &epoch->handle, sizeof(old)));
		DEBUG_REQ(D_HA, close_req, "updating close body with new fh");
		epoch->handle = body->mbo_handle;
	}
}

void mdc_commit_open(struct ptlrpc_request *req)
{
	struct md_open_data *mod = req->rq_cb_data;

	if (!mod)
		return;

	/**
	 * No need to touch md_open_data::mod_och, it holds a reference on
	 * \var mod and will zero references to each other, \var mod will be
	 * freed after that when md_open_data::mod_och will put the reference.
	 */

	/**
	 * Do not let open request to disappear as it still may be needed
	 * for close rpc to happen (it may happen on evict only, otherwise
	 * ptlrpc_request::rq_replay does not let mdc_commit_open() to be
	 * called), just mark this rpc as committed to distinguish these 2
	 * cases, see mdc_close() for details. The open request reference will
	 * be put along with freeing \var mod.
	 */
	ptlrpc_request_addref(req);
	spin_lock(&req->rq_lock);
	req->rq_committed = 1;
	spin_unlock(&req->rq_lock);
	req->rq_cb_data = NULL;
	obd_mod_put(mod);
}

int mdc_set_open_replay_data(struct obd_export *exp,
			     struct obd_client_handle *och,
			     struct lookup_intent *it)
{
	struct md_open_data   *mod;
	struct mdt_rec_create *rec;
	struct mdt_body       *body;
	struct ptlrpc_request *open_req = it->it_request;
	struct obd_import     *imp = open_req->rq_import;

	if (!open_req->rq_replay)
		return 0;

	rec = req_capsule_client_get(&open_req->rq_pill, &RMF_REC_REINT);
	body = req_capsule_server_get(&open_req->rq_pill, &RMF_MDT_BODY);
	LASSERT(rec);
	/* Incoming message in my byte order (it's been swabbed). */
	/* Outgoing messages always in my byte order. */
	LASSERT(body);

	/* Only if the import is replayable, we set replay_open data */
	if (och && imp->imp_replayable) {
		mod = obd_mod_alloc();
		if (!mod) {
			DEBUG_REQ(D_ERROR, open_req,
				  "Can't allocate md_open_data");
			return 0;
		}

		/**
		 * Take a reference on \var mod, to be freed on mdc_close().
		 * It protects \var mod from being freed on eviction (commit
		 * callback is called despite rq_replay flag).
		 * Another reference for \var och.
		 */
		obd_mod_get(mod);
		obd_mod_get(mod);

		spin_lock(&open_req->rq_lock);
		och->och_mod = mod;
		mod->mod_och = och;
		mod->mod_is_create = it_disposition(it, DISP_OPEN_CREATE) ||
				     it_disposition(it, DISP_OPEN_STRIPE);
		mod->mod_open_req = open_req;
		open_req->rq_cb_data = mod;
		open_req->rq_commit_cb = mdc_commit_open;
		spin_unlock(&open_req->rq_lock);
	}

	rec->cr_fid2 = body->mbo_fid1;
	rec->cr_ioepoch = body->mbo_ioepoch;
	rec->cr_old_handle.cookie = body->mbo_handle.cookie;
	open_req->rq_replay_cb = mdc_replay_open;
	if (!fid_is_sane(&body->mbo_fid1)) {
		DEBUG_REQ(D_ERROR, open_req,
			  "Saving replay request with insane fid");
		LBUG();
	}

	DEBUG_REQ(D_RPCTRACE, open_req, "Set up open replay data");
	return 0;
}

static void mdc_free_open(struct md_open_data *mod)
{
	int committed = 0;

	if (mod->mod_is_create == 0 &&
	    imp_connect_disp_stripe(mod->mod_open_req->rq_import))
		committed = 1;

	/*
	 * No reason to asssert here if the open request has
	 * rq_replay == 1. It means that mdc_close failed, and
	 * close request wasn`t sent. It is not fatal to client.
	 * The worst thing is eviction if the client gets open lock
	 */
	DEBUG_REQ(D_RPCTRACE, mod->mod_open_req,
		  "free open request rq_replay = %d\n",
		   mod->mod_open_req->rq_replay);

	ptlrpc_request_committed(mod->mod_open_req, committed);
	if (mod->mod_close_req)
		ptlrpc_request_committed(mod->mod_close_req, committed);
}

static int mdc_clear_open_replay_data(struct obd_export *exp,
				      struct obd_client_handle *och)
{
	struct md_open_data *mod = och->och_mod;

	/**
	 * It is possible to not have \var mod in a case of eviction between
	 * lookup and ll_file_open().
	 **/
	if (!mod)
		return 0;

	LASSERT(mod != LP_POISON);
	LASSERT(mod->mod_open_req);
	mdc_free_open(mod);

	mod->mod_och = NULL;
	och->och_mod = NULL;
	obd_mod_put(mod);

	return 0;
}

/* Prepares the request for the replay by the given reply */
static void mdc_close_handle_reply(struct ptlrpc_request *req,
				   struct md_op_data *op_data, int rc) {
	struct mdt_body  *repbody;
	struct mdt_ioepoch *epoch;

	if (req && rc == -EAGAIN) {
		repbody = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
		epoch = req_capsule_client_get(&req->rq_pill, &RMF_MDT_EPOCH);

		epoch->flags |= MF_SOM_AU;
		if (repbody->mbo_valid & OBD_MD_FLGETATTRLOCK)
			op_data->op_flags |= MF_GETATTR_LOCK;
	}
}

static int mdc_close(struct obd_export *exp, struct md_op_data *op_data,
		     struct md_open_data *mod, struct ptlrpc_request **request)
{
	struct obd_device     *obd = class_exp2obd(exp);
	struct ptlrpc_request *req;
	struct req_format     *req_fmt;
	int                    rc;
	int		       saved_rc = 0;

	req_fmt = &RQF_MDS_CLOSE;
	if (op_data->op_bias & MDS_HSM_RELEASE) {
		req_fmt = &RQF_MDS_RELEASE_CLOSE;

		/* allocate a FID for volatile file */
		rc = mdc_fid_alloc(NULL, exp, &op_data->op_fid2, op_data);
		if (rc < 0) {
			CERROR("%s: "DFID" failed to allocate FID: %d\n",
			       obd->obd_name, PFID(&op_data->op_fid1), rc);
			/* save the errcode and proceed to close */
			saved_rc = rc;
		}
	}

	*request = NULL;
	if (OBD_FAIL_CHECK(OBD_FAIL_MDC_CLOSE))
		req = NULL;
	else
		req = ptlrpc_request_alloc(class_exp2cliimp(exp), req_fmt);

	/* Ensure that this close's handle is fixed up during replay. */
	if (likely(mod)) {
		LASSERTF(mod->mod_open_req &&
			 mod->mod_open_req->rq_type != LI_POISON,
			 "POISONED open %p!\n", mod->mod_open_req);

		mod->mod_close_req = req;

		DEBUG_REQ(D_HA, mod->mod_open_req, "matched open");
		/* We no longer want to preserve this open for replay even
		 * though the open was committed. b=3632, b=3633
		 */
		spin_lock(&mod->mod_open_req->rq_lock);
		mod->mod_open_req->rq_replay = 0;
		spin_unlock(&mod->mod_open_req->rq_lock);
	} else {
		 CDEBUG(D_HA,
			"couldn't find open req; expecting close error\n");
	}
	if (!req) {
		/*
		 * TODO: repeat close after errors
		 */
		CWARN("%s: close of FID "DFID" failed, file reference will be dropped when this client unmounts or is evicted\n",
		      obd->obd_name, PFID(&op_data->op_fid1));
		rc = -ENOMEM;
		goto out;
	}

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_CLOSE);
	if (rc) {
		ptlrpc_request_free(req);
		goto out;
	}

	/*
	 * To avoid a livelock (bug 7034), we need to send CLOSE RPCs to a
	 * portal whose threads are not taking any DLM locks and are therefore
	 * always progressing
	 */
	req->rq_request_portal = MDS_READPAGE_PORTAL;
	ptlrpc_at_set_req_timeout(req);

	mdc_close_pack(req, op_data);

	req_capsule_set_size(&req->rq_pill, &RMF_MDT_MD, RCL_SERVER,
			     obd->u.cli.cl_default_mds_easize);
	req_capsule_set_size(&req->rq_pill, &RMF_LOGCOOKIES, RCL_SERVER,
			     obd->u.cli.cl_default_mds_cookiesize);

	ptlrpc_request_set_replen(req);

	mdc_get_rpc_lock(obd->u.cli.cl_close_lock, NULL);
	rc = ptlrpc_queue_wait(req);
	mdc_put_rpc_lock(obd->u.cli.cl_close_lock, NULL);

	if (!req->rq_repmsg) {
		CDEBUG(D_RPCTRACE, "request failed to send: %p, %d\n", req,
		       req->rq_status);
		if (rc == 0)
			rc = req->rq_status ?: -EIO;
	} else if (rc == 0 || rc == -EAGAIN) {
		struct mdt_body *body;

		rc = lustre_msg_get_status(req->rq_repmsg);
		if (lustre_msg_get_type(req->rq_repmsg) == PTL_RPC_MSG_ERR) {
			DEBUG_REQ(D_ERROR, req,
				  "type == PTL_RPC_MSG_ERR, err = %d", rc);
			if (rc > 0)
				rc = -rc;
		}
		body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
		if (!body)
			rc = -EPROTO;
	} else if (rc == -ESTALE) {
		/**
		 * it can be allowed error after 3633 if open was committed and
		 * server failed before close was sent. Let's check if mod
		 * exists and return no error in that case
		 */
		if (mod) {
			DEBUG_REQ(D_HA, req, "Reset ESTALE = %d", rc);
			if (mod->mod_open_req->rq_committed)
				rc = 0;
		}
	}

out:
	if (mod) {
		if (rc != 0)
			mod->mod_close_req = NULL;
		/* Since now, mod is accessed through open_req only,
		 * thus close req does not keep a reference on mod anymore.
		 */
		obd_mod_put(mod);
	}
	*request = req;
	mdc_close_handle_reply(req, op_data, rc);
	return rc < 0 ? rc : saved_rc;
}

static int mdc_done_writing(struct obd_export *exp, struct md_op_data *op_data,
			    struct md_open_data *mod)
{
	struct obd_device     *obd = class_exp2obd(exp);
	struct ptlrpc_request *req;
	int		    rc;

	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
				   &RQF_MDS_DONE_WRITING);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_DONE_WRITING);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	if (mod) {
		LASSERTF(mod->mod_open_req &&
			 mod->mod_open_req->rq_type != LI_POISON,
			 "POISONED setattr %p!\n", mod->mod_open_req);

		mod->mod_close_req = req;
		DEBUG_REQ(D_HA, mod->mod_open_req, "matched setattr");
		/* We no longer want to preserve this setattr for replay even
		 * though the open was committed. b=3632, b=3633
		 */
		spin_lock(&mod->mod_open_req->rq_lock);
		mod->mod_open_req->rq_replay = 0;
		spin_unlock(&mod->mod_open_req->rq_lock);
	}

	mdc_close_pack(req, op_data);
	ptlrpc_request_set_replen(req);

	mdc_get_rpc_lock(obd->u.cli.cl_close_lock, NULL);
	rc = ptlrpc_queue_wait(req);
	mdc_put_rpc_lock(obd->u.cli.cl_close_lock, NULL);

	if (rc == -ESTALE) {
		/**
		 * it can be allowed error after 3633 if open or setattr were
		 * committed and server failed before close was sent.
		 * Let's check if mod exists and return no error in that case
		 */
		if (mod) {
			if (mod->mod_open_req->rq_committed)
				rc = 0;
		}
	}

	if (mod) {
		if (rc != 0)
			mod->mod_close_req = NULL;
		LASSERT(mod->mod_open_req);
		mdc_free_open(mod);

		/* Since now, mod is accessed through setattr req only,
		 * thus DW req does not keep a reference on mod anymore.
		 */
		obd_mod_put(mod);
	}

	mdc_close_handle_reply(req, op_data, rc);
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_getpage(struct obd_export *exp, const struct lu_fid *fid,
		       u64 offset, struct page **pages, int npages,
		       struct ptlrpc_request **request)
{
	struct ptlrpc_bulk_desc *desc;
	struct ptlrpc_request *req;
	wait_queue_head_t waitq;
	struct l_wait_info lwi;
	int resends = 0;
	int rc;
	int i;

	*request = NULL;
	init_waitqueue_head(&waitq);

restart_bulk:
	req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_MDS_READPAGE);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_READPAGE);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	req->rq_request_portal = MDS_READPAGE_PORTAL;
	ptlrpc_at_set_req_timeout(req);

	desc = ptlrpc_prep_bulk_imp(req, npages, 1, BULK_PUT_SINK,
				    MDS_BULK_PORTAL);
	if (!desc) {
		ptlrpc_request_free(req);
		return -ENOMEM;
	}

	/* NB req now owns desc and will free it when it gets freed */
	for (i = 0; i < npages; i++)
		ptlrpc_prep_bulk_page_pin(desc, pages[i], 0, PAGE_SIZE);

	mdc_readdir_pack(req, offset, PAGE_SIZE * npages, fid);

	ptlrpc_request_set_replen(req);
	rc = ptlrpc_queue_wait(req);
	if (rc) {
		ptlrpc_req_finished(req);
		if (rc != -ETIMEDOUT)
			return rc;

		resends++;
		if (!client_should_resend(resends, &exp->exp_obd->u.cli)) {
			CERROR("%s: too many resend retries: rc = %d\n",
			       exp->exp_obd->obd_name, -EIO);
			return -EIO;
		}
		lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(resends), NULL, NULL,
				       NULL);
		l_wait_event(waitq, 0, &lwi);

		goto restart_bulk;
	}

	rc = sptlrpc_cli_unwrap_bulk_read(req, req->rq_bulk,
					  req->rq_bulk->bd_nob_transferred);
	if (rc < 0) {
		ptlrpc_req_finished(req);
		return rc;
	}

	if (req->rq_bulk->bd_nob_transferred & ~LU_PAGE_MASK) {
		CERROR("%s: unexpected bytes transferred: %d (%ld expected)\n",
		       exp->exp_obd->obd_name, req->rq_bulk->bd_nob_transferred,
		       PAGE_SIZE * npages);
		ptlrpc_req_finished(req);
		return -EPROTO;
	}

	*request = req;
	return 0;
}

static void mdc_release_page(struct page *page, int remove)
{
	if (remove) {
		lock_page(page);
		if (likely(page->mapping))
			truncate_complete_page(page->mapping, page);
		unlock_page(page);
	}
	put_page(page);
}

static struct page *mdc_page_locate(struct address_space *mapping, __u64 *hash,
				    __u64 *start, __u64 *end, int hash64)
{
	/*
	 * Complement of hash is used as an index so that
	 * radix_tree_gang_lookup() can be used to find a page with starting
	 * hash _smaller_ than one we are looking for.
	 */
	unsigned long offset = hash_x_index(*hash, hash64);
	struct page *page;
	int found;

	spin_lock_irq(&mapping->tree_lock);
	found = radix_tree_gang_lookup(&mapping->page_tree,
				       (void **)&page, offset, 1);
	if (found > 0 && !radix_tree_exceptional_entry(page)) {
		struct lu_dirpage *dp;

		get_page(page);
		spin_unlock_irq(&mapping->tree_lock);
		/*
		 * In contrast to find_lock_page() we are sure that directory
		 * page cannot be truncated (while DLM lock is held) and,
		 * hence, can avoid restart.
		 *
		 * In fact, page cannot be locked here at all, because
		 * mdc_read_page_remote does synchronous io.
		 */
		wait_on_page_locked(page);
		if (PageUptodate(page)) {
			dp = kmap(page);
			if (BITS_PER_LONG == 32 && hash64) {
				*start = le64_to_cpu(dp->ldp_hash_start) >> 32;
				*end   = le64_to_cpu(dp->ldp_hash_end) >> 32;
				*hash  = *hash >> 32;
			} else {
				*start = le64_to_cpu(dp->ldp_hash_start);
				*end   = le64_to_cpu(dp->ldp_hash_end);
			}
			if (unlikely(*start == 1 && *hash == 0))
				*hash = *start;
			else
				LASSERTF(*start <= *hash, "start = %#llx,end = %#llx,hash = %#llx\n",
					 *start, *end, *hash);
			CDEBUG(D_VFSTRACE, "offset %lx [%#llx %#llx], hash %#llx\n",
			       offset, *start, *end, *hash);
			if (*hash > *end) {
				kunmap(page);
				mdc_release_page(page, 0);
				page = NULL;
			} else if (*end != *start && *hash == *end) {
				/*
				 * upon hash collision, remove this page,
				 * otherwise put page reference, and
				 * mdc_read_page_remote() will issue RPC to
				 * fetch the page we want.
				 */
				kunmap(page);
				mdc_release_page(page,
						 le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
				page = NULL;
			}
		} else {
			put_page(page);
			page = ERR_PTR(-EIO);
		}
	} else {
		spin_unlock_irq(&mapping->tree_lock);
		page = NULL;
	}
	return page;
}

/*
 * Adjust a set of pages, each page containing an array of lu_dirpages,
 * so that each page can be used as a single logical lu_dirpage.
 *
 * A lu_dirpage is laid out as follows, where s = ldp_hash_start,
 * e = ldp_hash_end, f = ldp_flags, p = padding, and each "ent" is a
 * struct lu_dirent.  It has size up to LU_PAGE_SIZE. The ldp_hash_end
 * value is used as a cookie to request the next lu_dirpage in a
 * directory listing that spans multiple pages (two in this example):
 *   ________
 *  |        |
 * .|--------v-------   -----.
 * |s|e|f|p|ent|ent| ... |ent|
 * '--|--------------   -----'   Each PAGE contains a single
 *    '------.                   lu_dirpage.
 * .---------v-------   -----.
 * |s|e|f|p|ent| 0 | ... | 0 |
 * '-----------------   -----'
 *
 * However, on hosts where the native VM page size (PAGE_SIZE) is
 * larger than LU_PAGE_SIZE, a single host page may contain multiple
 * lu_dirpages. After reading the lu_dirpages from the MDS, the
 * ldp_hash_end of the first lu_dirpage refers to the one immediately
 * after it in the same PAGE (arrows simplified for brevity, but
 * in general e0==s1, e1==s2, etc.):
 *
 * .--------------------   -----.
 * |s0|e0|f0|p|ent|ent| ... |ent|
 * |---v----------------   -----|
 * |s1|e1|f1|p|ent|ent| ... |ent|
 * |---v----------------   -----|  Here, each PAGE contains
 *             ...                 multiple lu_dirpages.
 * |---v----------------   -----|
 * |s'|e'|f'|p|ent|ent| ... |ent|
 * '---|----------------   -----'
 *     v
 * .----------------------------.
 * |        next PAGE           |
 *
 * This structure is transformed into a single logical lu_dirpage as follows:
 *
 * - Replace e0 with e' so the request for the next lu_dirpage gets the page
 *   labeled 'next PAGE'.
 *
 * - Copy the LDF_COLLIDE flag from f' to f0 to correctly reflect whether
 *   a hash collision with the next page exists.
 *
 * - Adjust the lde_reclen of the ending entry of each lu_dirpage to span
 *   to the first entry of the next lu_dirpage.
 */
#if PAGE_SIZE > LU_PAGE_SIZE
static void mdc_adjust_dirpages(struct page **pages, int cfs_pgs, int lu_pgs)
{
	int i;

	for (i = 0; i < cfs_pgs; i++) {
		struct lu_dirpage *dp = kmap(pages[i]);
		__u64 hash_end = le64_to_cpu(dp->ldp_hash_end);
		__u32 flags = le32_to_cpu(dp->ldp_flags);
		struct lu_dirpage *first = dp;
		struct lu_dirent *end_dirent = NULL;
		struct lu_dirent *ent;

		while (--lu_pgs > 0) {
			ent = lu_dirent_start(dp);
			for (end_dirent = ent; ent;
			     end_dirent = ent, ent = lu_dirent_next(ent));

			/* Advance dp to next lu_dirpage. */
			dp = (struct lu_dirpage *)((char *)dp + LU_PAGE_SIZE);

			/* Check if we've reached the end of the CFS_PAGE. */
			if (!((unsigned long)dp & ~PAGE_MASK))
				break;

			/* Save the hash and flags of this lu_dirpage. */
			hash_end = le64_to_cpu(dp->ldp_hash_end);
			flags = le32_to_cpu(dp->ldp_flags);

			/* Check if lu_dirpage contains no entries. */
			if (!end_dirent)
				break;

			/*
			 * Enlarge the end entry lde_reclen from 0 to
			 * first entry of next lu_dirpage.
			 */
			LASSERT(!le16_to_cpu(end_dirent->lde_reclen));
			end_dirent->lde_reclen =
				cpu_to_le16((char *)(dp->ldp_entries) -
					    (char *)end_dirent);
		}

		first->ldp_hash_end = hash_end;
		first->ldp_flags &= ~cpu_to_le32(LDF_COLLIDE);
		first->ldp_flags |= flags & cpu_to_le32(LDF_COLLIDE);

		kunmap(pages[i]);
	}
	LASSERTF(lu_pgs == 0, "left = %d", lu_pgs);
}
#else
#define mdc_adjust_dirpages(pages, cfs_pgs, lu_pgs) do {} while (0)
#endif  /* PAGE_SIZE > LU_PAGE_SIZE */

/* parameters for readdir page */
struct readpage_param {
	struct md_op_data	*rp_mod;
	__u64			rp_off;
	int			rp_hash64;
	struct obd_export	*rp_exp;
	struct md_callback	*rp_cb;
};

/**
 * Read pages from server.
 *
 * Page in MDS_READPAGE RPC is packed in LU_PAGE_SIZE, and each page contains
 * a header lu_dirpage which describes the start/end hash, and whether this
 * page is empty (contains no dir entry) or hash collide with next page.
 * After client receives reply, several pages will be integrated into dir page
 * in PAGE_SIZE (if PAGE_SIZE greater than LU_PAGE_SIZE), and the
 * lu_dirpage for this integrated page will be adjusted.
 **/
static int mdc_read_page_remote(void *data, struct page *page0)
{
	struct readpage_param *rp = data;
	struct page **page_pool;
	struct page *page;
	struct lu_dirpage *dp;
	int rd_pgs = 0; /* number of pages read actually */
	int npages;
	struct md_op_data *op_data = rp->rp_mod;
	struct ptlrpc_request *req;
	int max_pages = op_data->op_max_pages;
	struct inode *inode;
	struct lu_fid *fid;
	int i;
	int rc;

	LASSERT(max_pages > 0 && max_pages <= PTLRPC_MAX_BRW_PAGES);
	inode = op_data->op_data;
	fid = &op_data->op_fid1;
	LASSERT(inode);

	page_pool = kcalloc(max_pages, sizeof(page), GFP_NOFS);
	if (page_pool) {
		page_pool[0] = page0;
	} else {
		page_pool = &page0;
		max_pages = 1;
	}

	for (npages = 1; npages < max_pages; npages++) {
		page = page_cache_alloc_cold(inode->i_mapping);
		if (!page)
			break;
		page_pool[npages] = page;
	}

	rc = mdc_getpage(rp->rp_exp, fid, rp->rp_off, page_pool, npages, &req);
	if (!rc) {
		int lu_pgs = req->rq_bulk->bd_nob_transferred;

		rd_pgs = (req->rq_bulk->bd_nob_transferred +
			  PAGE_SIZE - 1) >> PAGE_SHIFT;
		lu_pgs >>= LU_PAGE_SHIFT;
		LASSERT(!(req->rq_bulk->bd_nob_transferred & ~LU_PAGE_MASK));

		CDEBUG(D_INODE, "read %d(%d) pages\n", rd_pgs, lu_pgs);

		mdc_adjust_dirpages(page_pool, rd_pgs, lu_pgs);

		SetPageUptodate(page0);
	}

	unlock_page(page0);
	ptlrpc_req_finished(req);
	CDEBUG(D_CACHE, "read %d/%d pages\n", rd_pgs, npages);
	for (i = 1; i < npages; i++) {
		unsigned long offset;
		__u64 hash;
		int ret;

		page = page_pool[i];

		if (rc < 0 || i >= rd_pgs) {
			put_page(page);
			continue;
		}

		SetPageUptodate(page);

		dp = kmap(page);
		hash = le64_to_cpu(dp->ldp_hash_start);
		kunmap(page);

		offset = hash_x_index(hash, rp->rp_hash64);

		prefetchw(&page->flags);
		ret = add_to_page_cache_lru(page, inode->i_mapping, offset,
					    GFP_KERNEL);
		if (!ret)
			unlock_page(page);
		else
			CDEBUG(D_VFSTRACE, "page %lu add to page cache failed: rc = %d\n",
			       offset, ret);
		put_page(page);
	}

	if (page_pool != &page0)
		kfree(page_pool);

	return rc;
}

/**
 * Read dir page from cache first, if it can not find it, read it from
 * server and add into the cache.
 *
 * \param[in] exp	MDC export
 * \param[in] op_data	client MD stack parameters, transferring parameters
 *			between different layers on client MD stack.
 * \param[in] cb_op	callback required for ldlm lock enqueue during
 *			read page
 * \param[in] hash_offset the hash offset of the page to be read
 * \param[in] ppage	the page to be read
 *
 * retval		= 0 get the page successfully
 *			errno(<0) get the page failed
 */
static int mdc_read_page(struct obd_export *exp, struct md_op_data *op_data,
			 struct md_callback *cb_op, __u64 hash_offset,
			 struct page **ppage)
{
	struct lookup_intent it = { .it_op = IT_READDIR };
	struct page *page;
	struct inode *dir = op_data->op_data;
	struct address_space *mapping;
	struct lu_dirpage *dp;
	__u64 start = 0;
	__u64 end = 0;
	struct lustre_handle lockh;
	struct ptlrpc_request *enq_req = NULL;
	struct readpage_param rp_param;
	int rc;

	*ppage = NULL;

	LASSERT(dir);
	mapping = dir->i_mapping;

	rc = mdc_intent_lock(exp, op_data, &it, &enq_req,
			     cb_op->md_blocking_ast, 0);
	if (enq_req)
		ptlrpc_req_finished(enq_req);

	if (rc < 0) {
		CERROR("%s: "DFID" lock enqueue fails: rc = %d\n",
		       exp->exp_obd->obd_name, PFID(&op_data->op_fid1), rc);
		return rc;
	}

	rc = 0;
	lockh.cookie = it.it_lock_handle;
	mdc_set_lock_data(exp, &lockh, dir, NULL);

	rp_param.rp_off = hash_offset;
	rp_param.rp_hash64 = op_data->op_cli_flags & CLI_HASH64;
	page = mdc_page_locate(mapping, &rp_param.rp_off, &start, &end,
			       rp_param.rp_hash64);
	if (IS_ERR(page)) {
		CDEBUG(D_INFO, "%s: dir page locate: " DFID " at %llu: rc %ld\n",
		       exp->exp_obd->obd_name, PFID(&op_data->op_fid1),
		       rp_param.rp_off, PTR_ERR(page));
		rc = PTR_ERR(page);
		goto out_unlock;
	} else if (page) {
		/*
		 * XXX nikita: not entirely correct handling of a corner case:
		 * suppose hash chain of entries with hash value HASH crosses
		 * border between pages P0 and P1. First both P0 and P1 are
		 * cached, seekdir() is called for some entry from the P0 part
		 * of the chain. Later P0 goes out of cache. telldir(HASH)
		 * happens and finds P1, as it starts with matching hash
		 * value. Remaining entries from P0 part of the chain are
		 * skipped. (Is that really a bug?)
		 *
		 * Possible solutions: 0. don't cache P1 is such case, handle
		 * it as an "overflow" page. 1. invalidate all pages at
		 * once. 2. use HASH|1 as an index for P1.
		 */
		goto hash_collision;
	}

	rp_param.rp_exp = exp;
	rp_param.rp_mod = op_data;
	page = read_cache_page(mapping,
			       hash_x_index(rp_param.rp_off,
					    rp_param.rp_hash64),
			       mdc_read_page_remote, &rp_param);
	if (IS_ERR(page)) {
		CERROR("%s: read cache page: "DFID" at %llu: rc %ld\n",
		       exp->exp_obd->obd_name, PFID(&op_data->op_fid1),
		       rp_param.rp_off, PTR_ERR(page));
		rc = PTR_ERR(page);
		goto out_unlock;
	}

	wait_on_page_locked(page);
	(void)kmap(page);
	if (!PageUptodate(page)) {
		CERROR("%s: page not updated: "DFID" at %llu: rc %d\n",
		       exp->exp_obd->obd_name, PFID(&op_data->op_fid1),
		       rp_param.rp_off, -5);
		goto fail;
	}
	if (!PageChecked(page))
		SetPageChecked(page);
	if (PageError(page)) {
		CERROR("%s: page error: "DFID" at %llu: rc %d\n",
		       exp->exp_obd->obd_name, PFID(&op_data->op_fid1),
		       rp_param.rp_off, -5);
		goto fail;
	}

hash_collision:
	dp = page_address(page);
	if (BITS_PER_LONG == 32 && rp_param.rp_hash64) {
		start = le64_to_cpu(dp->ldp_hash_start) >> 32;
		end = le64_to_cpu(dp->ldp_hash_end) >> 32;
		rp_param.rp_off = hash_offset >> 32;
	} else {
		start = le64_to_cpu(dp->ldp_hash_start);
		end = le64_to_cpu(dp->ldp_hash_end);
		rp_param.rp_off = hash_offset;
	}
	if (end == start) {
		LASSERT(start == rp_param.rp_off);
		CWARN("Page-wide hash collision: %#lx\n", (unsigned long)end);
#if BITS_PER_LONG == 32
		CWARN("Real page-wide hash collision at [%llu %llu] with hash %llu\n",
		      le64_to_cpu(dp->ldp_hash_start),
		      le64_to_cpu(dp->ldp_hash_end), hash_offset);
#endif
		/*
		 * Fetch whole overflow chain...
		 *
		 * XXX not yet.
		 */
		goto fail;
	}
	*ppage = page;
out_unlock:
	ldlm_lock_decref(&lockh, it.it_lock_mode);
	return rc;
fail:
	kunmap(page);
	mdc_release_page(page, 1);
	rc = -EIO;
	goto out_unlock;
}

static int mdc_statfs(const struct lu_env *env,
		      struct obd_export *exp, struct obd_statfs *osfs,
		      __u64 max_age, __u32 flags)
{
	struct obd_device     *obd = class_exp2obd(exp);
	struct ptlrpc_request *req;
	struct obd_statfs     *msfs;
	struct obd_import     *imp = NULL;
	int		    rc;

	/*
	 * Since the request might also come from lprocfs, so we need
	 * sync this with client_disconnect_export Bug15684
	 */
	down_read(&obd->u.cli.cl_sem);
	if (obd->u.cli.cl_import)
		imp = class_import_get(obd->u.cli.cl_import);
	up_read(&obd->u.cli.cl_sem);
	if (!imp)
		return -ENODEV;

	req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_STATFS,
					LUSTRE_MDS_VERSION, MDS_STATFS);
	if (!req) {
		rc = -ENOMEM;
		goto output;
	}

	ptlrpc_request_set_replen(req);

	if (flags & OBD_STATFS_NODELAY) {
		/* procfs requests not want stay in wait for avoid deadlock */
		req->rq_no_resend = 1;
		req->rq_no_delay = 1;
	}

	rc = ptlrpc_queue_wait(req);
	if (rc) {
		/* check connection error first */
		if (imp->imp_connect_error)
			rc = imp->imp_connect_error;
		goto out;
	}

	msfs = req_capsule_server_get(&req->rq_pill, &RMF_OBD_STATFS);
	if (!msfs) {
		rc = -EPROTO;
		goto out;
	}

	*osfs = *msfs;
out:
	ptlrpc_req_finished(req);
output:
	class_import_put(imp);
	return rc;
}

static int mdc_ioc_fid2path(struct obd_export *exp, struct getinfo_fid2path *gf)
{
	__u32 keylen, vallen;
	void *key;
	int rc;

	if (gf->gf_pathlen > PATH_MAX)
		return -ENAMETOOLONG;
	if (gf->gf_pathlen < 2)
		return -EOVERFLOW;

	/* Key is KEY_FID2PATH + getinfo_fid2path description */
	keylen = cfs_size_round(sizeof(KEY_FID2PATH)) + sizeof(*gf);
	key = kzalloc(keylen, GFP_NOFS);
	if (!key)
		return -ENOMEM;
	memcpy(key, KEY_FID2PATH, sizeof(KEY_FID2PATH));
	memcpy(key + cfs_size_round(sizeof(KEY_FID2PATH)), gf, sizeof(*gf));

	CDEBUG(D_IOCTL, "path get "DFID" from %llu #%d\n",
	       PFID(&gf->gf_fid), gf->gf_recno, gf->gf_linkno);

	if (!fid_is_sane(&gf->gf_fid)) {
		rc = -EINVAL;
		goto out;
	}

	/* Val is struct getinfo_fid2path result plus path */
	vallen = sizeof(*gf) + gf->gf_pathlen;

	rc = obd_get_info(NULL, exp, keylen, key, &vallen, gf, NULL);
	if (rc != 0 && rc != -EREMOTE)
		goto out;

	if (vallen <= sizeof(*gf)) {
		rc = -EPROTO;
		goto out;
	} else if (vallen > sizeof(*gf) + gf->gf_pathlen) {
		rc = -EOVERFLOW;
		goto out;
	}

	CDEBUG(D_IOCTL, "path get "DFID" from %llu #%d\n%s\n",
	       PFID(&gf->gf_fid), gf->gf_recno, gf->gf_linkno, gf->gf_path);

out:
	kfree(key);
	return rc;
}

static int mdc_ioc_hsm_progress(struct obd_export *exp,
				struct hsm_progress_kernel *hpk)
{
	struct obd_import		*imp = class_exp2cliimp(exp);
	struct hsm_progress_kernel	*req_hpk;
	struct ptlrpc_request		*req;
	int				 rc;

	req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_HSM_PROGRESS,
					LUSTRE_MDS_VERSION, MDS_HSM_PROGRESS);
	if (!req) {
		rc = -ENOMEM;
		goto out;
	}

	mdc_pack_body(req, NULL, 0, 0, -1, 0);

	/* Copy hsm_progress struct */
	req_hpk = req_capsule_client_get(&req->rq_pill, &RMF_MDS_HSM_PROGRESS);
	if (!req_hpk) {
		rc = -EPROTO;
		goto out;
	}

	*req_hpk = *hpk;
	req_hpk->hpk_errval = lustre_errno_hton(hpk->hpk_errval);

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
out:
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_ioc_hsm_ct_register(struct obd_import *imp, __u32 archives)
{
	__u32			*archive_mask;
	struct ptlrpc_request	*req;
	int			 rc;

	req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_HSM_CT_REGISTER,
					LUSTRE_MDS_VERSION,
					MDS_HSM_CT_REGISTER);
	if (!req) {
		rc = -ENOMEM;
		goto out;
	}

	mdc_pack_body(req, NULL, 0, 0, -1, 0);

	/* Copy hsm_progress struct */
	archive_mask = req_capsule_client_get(&req->rq_pill,
					      &RMF_MDS_HSM_ARCHIVE);
	if (!archive_mask) {
		rc = -EPROTO;
		goto out;
	}

	*archive_mask = archives;

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
out:
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_ioc_hsm_current_action(struct obd_export *exp,
				      struct md_op_data *op_data)
{
	struct hsm_current_action	*hca = op_data->op_data;
	struct hsm_current_action	*req_hca;
	struct ptlrpc_request		*req;
	int				 rc;

	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
				   &RQF_MDS_HSM_ACTION);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_HSM_ACTION);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, &op_data->op_fid1, 0, 0,
		      op_data->op_suppgids[0], 0);

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
	if (rc)
		goto out;

	req_hca = req_capsule_server_get(&req->rq_pill,
					 &RMF_MDS_HSM_CURRENT_ACTION);
	if (!req_hca) {
		rc = -EPROTO;
		goto out;
	}

	*hca = *req_hca;

out:
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_ioc_hsm_ct_unregister(struct obd_import *imp)
{
	struct ptlrpc_request	*req;
	int			 rc;

	req = ptlrpc_request_alloc_pack(imp, &RQF_MDS_HSM_CT_UNREGISTER,
					LUSTRE_MDS_VERSION,
					MDS_HSM_CT_UNREGISTER);
	if (!req) {
		rc = -ENOMEM;
		goto out;
	}

	mdc_pack_body(req, NULL, 0, 0, -1, 0);

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
out:
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_ioc_hsm_state_get(struct obd_export *exp,
				 struct md_op_data *op_data)
{
	struct hsm_user_state	*hus = op_data->op_data;
	struct hsm_user_state	*req_hus;
	struct ptlrpc_request	*req;
	int			 rc;

	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
				   &RQF_MDS_HSM_STATE_GET);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_HSM_STATE_GET);
	if (rc != 0) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, &op_data->op_fid1, 0, 0,
		      op_data->op_suppgids[0], 0);

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
	if (rc)
		goto out;

	req_hus = req_capsule_server_get(&req->rq_pill, &RMF_HSM_USER_STATE);
	if (!req_hus) {
		rc = -EPROTO;
		goto out;
	}

	*hus = *req_hus;

out:
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_ioc_hsm_state_set(struct obd_export *exp,
				 struct md_op_data *op_data)
{
	struct hsm_state_set	*hss = op_data->op_data;
	struct hsm_state_set	*req_hss;
	struct ptlrpc_request	*req;
	int			 rc;

	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
				   &RQF_MDS_HSM_STATE_SET);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_HSM_STATE_SET);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, &op_data->op_fid1, 0, 0,
		      op_data->op_suppgids[0], 0);

	/* Copy states */
	req_hss = req_capsule_client_get(&req->rq_pill, &RMF_HSM_STATE_SET);
	if (!req_hss) {
		rc = -EPROTO;
		goto out;
	}
	*req_hss = *hss;

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
out:
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_ioc_hsm_request(struct obd_export *exp,
			       struct hsm_user_request *hur)
{
	struct obd_import	*imp = class_exp2cliimp(exp);
	struct ptlrpc_request	*req;
	struct hsm_request	*req_hr;
	struct hsm_user_item	*req_hui;
	char			*req_opaque;
	int			 rc;

	req = ptlrpc_request_alloc(imp, &RQF_MDS_HSM_REQUEST);
	if (!req) {
		rc = -ENOMEM;
		goto out;
	}

	req_capsule_set_size(&req->rq_pill, &RMF_MDS_HSM_USER_ITEM, RCL_CLIENT,
			     hur->hur_request.hr_itemcount
			     * sizeof(struct hsm_user_item));
	req_capsule_set_size(&req->rq_pill, &RMF_GENERIC_DATA, RCL_CLIENT,
			     hur->hur_request.hr_data_len);

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_HSM_REQUEST);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, NULL, 0, 0, -1, 0);

	/* Copy hsm_request struct */
	req_hr = req_capsule_client_get(&req->rq_pill, &RMF_MDS_HSM_REQUEST);
	if (!req_hr) {
		rc = -EPROTO;
		goto out;
	}
	*req_hr = hur->hur_request;

	/* Copy hsm_user_item structs */
	req_hui = req_capsule_client_get(&req->rq_pill, &RMF_MDS_HSM_USER_ITEM);
	if (!req_hui) {
		rc = -EPROTO;
		goto out;
	}
	memcpy(req_hui, hur->hur_user_item,
	       hur->hur_request.hr_itemcount * sizeof(struct hsm_user_item));

	/* Copy opaque field */
	req_opaque = req_capsule_client_get(&req->rq_pill, &RMF_GENERIC_DATA);
	if (!req_opaque) {
		rc = -EPROTO;
		goto out;
	}
	memcpy(req_opaque, hur_data(hur), hur->hur_request.hr_data_len);

	ptlrpc_request_set_replen(req);

	rc = mdc_queue_wait(req);
out:
	ptlrpc_req_finished(req);
	return rc;
}

static struct kuc_hdr *changelog_kuc_hdr(char *buf, size_t len, u32 flags)
{
	struct kuc_hdr *lh = (struct kuc_hdr *)buf;

	LASSERT(len <= KUC_CHANGELOG_MSG_MAXSIZE);

	lh->kuc_magic = KUC_MAGIC;
	lh->kuc_transport = KUC_TRANSPORT_CHANGELOG;
	lh->kuc_flags = flags;
	lh->kuc_msgtype = CL_RECORD;
	lh->kuc_msglen = len;
	return lh;
}

struct changelog_show {
	__u64		cs_startrec;
	enum changelog_send_flag	cs_flags;
	struct file	*cs_fp;
	char		*cs_buf;
	struct obd_device *cs_obd;
};

static inline char *cs_obd_name(struct changelog_show *cs)
{
	return cs->cs_obd->obd_name;
}

static int changelog_kkuc_cb(const struct lu_env *env, struct llog_handle *llh,
			     struct llog_rec_hdr *hdr, void *data)
{
	struct changelog_show *cs = data;
	struct llog_changelog_rec *rec = (struct llog_changelog_rec *)hdr;
	struct kuc_hdr *lh;
	size_t len;
	int rc;

	if (rec->cr_hdr.lrh_type != CHANGELOG_REC) {
		rc = -EINVAL;
		CERROR("%s: not a changelog rec %x/%d: rc = %d\n",
		       cs_obd_name(cs), rec->cr_hdr.lrh_type,
		       rec->cr.cr_type, rc);
		return rc;
	}

	if (rec->cr.cr_index < cs->cs_startrec) {
		/* Skip entries earlier than what we are interested in */
		CDEBUG(D_HSM, "rec=%llu start=%llu\n",
		       rec->cr.cr_index, cs->cs_startrec);
		return 0;
	}

	CDEBUG(D_HSM, "%llu %02d%-5s %llu 0x%x t=" DFID " p=" DFID
		" %.*s\n", rec->cr.cr_index, rec->cr.cr_type,
		changelog_type2str(rec->cr.cr_type), rec->cr.cr_time,
		rec->cr.cr_flags & CLF_FLAGMASK,
		PFID(&rec->cr.cr_tfid), PFID(&rec->cr.cr_pfid),
		rec->cr.cr_namelen, changelog_rec_name(&rec->cr));

	len = sizeof(*lh) + changelog_rec_size(&rec->cr) + rec->cr.cr_namelen;

	/* Set up the message */
	lh = changelog_kuc_hdr(cs->cs_buf, len, cs->cs_flags);
	memcpy(lh + 1, &rec->cr, len - sizeof(*lh));

	rc = libcfs_kkuc_msg_put(cs->cs_fp, lh);
	CDEBUG(D_HSM, "kucmsg fp %p len %zu rc %d\n", cs->cs_fp, len, rc);

	return rc;
}

static int mdc_changelog_send_thread(void *csdata)
{
	enum llog_flag flags = LLOG_F_IS_CAT;
	struct changelog_show *cs = csdata;
	struct llog_ctxt *ctxt = NULL;
	struct llog_handle *llh = NULL;
	struct kuc_hdr *kuch;
	int rc;

	CDEBUG(D_HSM, "changelog to fp=%p start %llu\n",
	       cs->cs_fp, cs->cs_startrec);

	cs->cs_buf = kzalloc(KUC_CHANGELOG_MSG_MAXSIZE, GFP_NOFS);
	if (!cs->cs_buf) {
		rc = -ENOMEM;
		goto out;
	}

	/* Set up the remote catalog handle */
	ctxt = llog_get_context(cs->cs_obd, LLOG_CHANGELOG_REPL_CTXT);
	if (!ctxt) {
		rc = -ENOENT;
		goto out;
	}
	rc = llog_open(NULL, ctxt, &llh, NULL, CHANGELOG_CATALOG,
		       LLOG_OPEN_EXISTS);
	if (rc) {
		CERROR("%s: fail to open changelog catalog: rc = %d\n",
		       cs_obd_name(cs), rc);
		goto out;
	}

	if (cs->cs_flags & CHANGELOG_FLAG_JOBID)
		flags |= LLOG_F_EXT_JOBID;

	rc = llog_init_handle(NULL, llh, flags, NULL);
	if (rc) {
		CERROR("llog_init_handle failed %d\n", rc);
		goto out;
	}

	rc = llog_cat_process(NULL, llh, changelog_kkuc_cb, cs, 0, 0);

	/* Send EOF no matter what our result */
	kuch = changelog_kuc_hdr(cs->cs_buf, sizeof(*kuch), cs->cs_flags);
	if (kuch) {
		kuch->kuc_msgtype = CL_EOF;
		libcfs_kkuc_msg_put(cs->cs_fp, kuch);
	}

out:
	fput(cs->cs_fp);
	if (llh)
		llog_cat_close(NULL, llh);
	if (ctxt)
		llog_ctxt_put(ctxt);
	kfree(cs->cs_buf);
	kfree(cs);
	return rc;
}

static int mdc_ioc_changelog_send(struct obd_device *obd,
				  struct ioc_changelog *icc)
{
	struct changelog_show *cs;
	struct task_struct *task;
	int rc;

	/* Freed in mdc_changelog_send_thread */
	cs = kzalloc(sizeof(*cs), GFP_NOFS);
	if (!cs)
		return -ENOMEM;

	cs->cs_obd = obd;
	cs->cs_startrec = icc->icc_recno;
	/* matching fput in mdc_changelog_send_thread */
	cs->cs_fp = fget(icc->icc_id);
	cs->cs_flags = icc->icc_flags;

	/*
	 * New thread because we should return to user app before
	 * writing into our pipe
	 */
	task = kthread_run(mdc_changelog_send_thread, cs,
			   "mdc_clg_send_thread");
	if (IS_ERR(task)) {
		rc = PTR_ERR(task);
		CERROR("%s: can't start changelog thread: rc = %d\n",
		       cs_obd_name(cs), rc);
		kfree(cs);
	} else {
		rc = 0;
		CDEBUG(D_HSM, "%s: started changelog thread\n",
		       cs_obd_name(cs));
	}

	CERROR("Failed to start changelog thread: %d\n", rc);
	return rc;
}

static int mdc_ioc_hsm_ct_start(struct obd_export *exp,
				struct lustre_kernelcomm *lk);

static int mdc_quotacheck(struct obd_device *unused, struct obd_export *exp,
			  struct obd_quotactl *oqctl)
{
	struct client_obd       *cli = &exp->exp_obd->u.cli;
	struct ptlrpc_request   *req;
	struct obd_quotactl     *body;
	int		      rc;

	req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
					&RQF_MDS_QUOTACHECK, LUSTRE_MDS_VERSION,
					MDS_QUOTACHECK);
	if (!req)
		return -ENOMEM;

	body = req_capsule_client_get(&req->rq_pill, &RMF_OBD_QUOTACTL);
	*body = *oqctl;

	ptlrpc_request_set_replen(req);

	/* the next poll will find -ENODATA, that means quotacheck is
	 * going on
	 */
	cli->cl_qchk_stat = -ENODATA;
	rc = ptlrpc_queue_wait(req);
	if (rc)
		cli->cl_qchk_stat = rc;
	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_quota_poll_check(struct obd_export *exp,
				struct if_quotacheck *qchk)
{
	struct client_obd *cli = &exp->exp_obd->u.cli;
	int rc;

	qchk->obd_uuid = cli->cl_target_uuid;
	memcpy(qchk->obd_type, LUSTRE_MDS_NAME, strlen(LUSTRE_MDS_NAME));

	rc = cli->cl_qchk_stat;
	/* the client is not the previous one */
	if (rc == CL_NOT_QUOTACHECKED)
		rc = -EINTR;
	return rc;
}

static int mdc_quotactl(struct obd_device *unused, struct obd_export *exp,
			struct obd_quotactl *oqctl)
{
	struct ptlrpc_request   *req;
	struct obd_quotactl     *oqc;
	int		      rc;

	req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
					&RQF_MDS_QUOTACTL, LUSTRE_MDS_VERSION,
					MDS_QUOTACTL);
	if (!req)
		return -ENOMEM;

	oqc = req_capsule_client_get(&req->rq_pill, &RMF_OBD_QUOTACTL);
	*oqc = *oqctl;

	ptlrpc_request_set_replen(req);
	ptlrpc_at_set_req_timeout(req);
	req->rq_no_resend = 1;

	rc = ptlrpc_queue_wait(req);
	if (rc)
		CERROR("ptlrpc_queue_wait failed, rc: %d\n", rc);

	if (req->rq_repmsg) {
		oqc = req_capsule_server_get(&req->rq_pill, &RMF_OBD_QUOTACTL);
		if (oqc) {
			*oqctl = *oqc;
		} else if (!rc) {
			CERROR("Can't unpack obd_quotactl\n");
			rc = -EPROTO;
		}
	} else if (!rc) {
		CERROR("Can't unpack obd_quotactl\n");
		rc = -EPROTO;
	}
	ptlrpc_req_finished(req);

	return rc;
}

static int mdc_ioc_swap_layouts(struct obd_export *exp,
				struct md_op_data *op_data)
{
	LIST_HEAD(cancels);
	struct ptlrpc_request	*req;
	int			 rc, count;
	struct mdc_swap_layouts *msl, *payload;

	msl = op_data->op_data;

	/* When the MDT will get the MDS_SWAP_LAYOUTS RPC the
	 * first thing it will do is to cancel the 2 layout
	 * locks hold by this client.
	 * So the client must cancel its layout locks on the 2 fids
	 * with the request RPC to avoid extra RPC round trips
	 */
	count = mdc_resource_get_unused(exp, &op_data->op_fid1, &cancels,
					LCK_CR, MDS_INODELOCK_LAYOUT |
					MDS_INODELOCK_XATTR);
	count += mdc_resource_get_unused(exp, &op_data->op_fid2, &cancels,
					 LCK_CR, MDS_INODELOCK_LAYOUT |
					 MDS_INODELOCK_XATTR);

	req = ptlrpc_request_alloc(class_exp2cliimp(exp),
				   &RQF_MDS_SWAP_LAYOUTS);
	if (!req) {
		ldlm_lock_list_put(&cancels, l_bl_ast, count);
		return -ENOMEM;
	}

	rc = mdc_prep_elc_req(exp, req, MDS_SWAP_LAYOUTS, &cancels, count);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_swap_layouts_pack(req, op_data);

	payload = req_capsule_client_get(&req->rq_pill, &RMF_SWAP_LAYOUTS);
	LASSERT(payload);

	*payload = *msl;

	ptlrpc_request_set_replen(req);

	rc = ptlrpc_queue_wait(req);

	ptlrpc_req_finished(req);
	return rc;
}

static int mdc_iocontrol(unsigned int cmd, struct obd_export *exp, int len,
			 void *karg, void __user *uarg)
{
	struct obd_device *obd = exp->exp_obd;
	struct obd_ioctl_data *data = karg;
	struct obd_import *imp = obd->u.cli.cl_import;
	int rc;

	if (!try_module_get(THIS_MODULE)) {
		CERROR("%s: cannot get module '%s'\n", obd->obd_name,
		       module_name(THIS_MODULE));
		return -EINVAL;
	}
	switch (cmd) {
	case OBD_IOC_CHANGELOG_SEND:
		rc = mdc_ioc_changelog_send(obd, karg);
		goto out;
	case OBD_IOC_CHANGELOG_CLEAR: {
		struct ioc_changelog *icc = karg;
		struct changelog_setinfo cs = {
			.cs_recno = icc->icc_recno,
			.cs_id = icc->icc_id
		};

		rc = obd_set_info_async(NULL, exp, strlen(KEY_CHANGELOG_CLEAR),
					KEY_CHANGELOG_CLEAR, sizeof(cs), &cs,
					NULL);
		goto out;
	}
	case OBD_IOC_FID2PATH:
		rc = mdc_ioc_fid2path(exp, karg);
		goto out;
	case LL_IOC_HSM_CT_START:
		rc = mdc_ioc_hsm_ct_start(exp, karg);
		/* ignore if it was already registered on this MDS. */
		if (rc == -EEXIST)
			rc = 0;
		goto out;
	case LL_IOC_HSM_PROGRESS:
		rc = mdc_ioc_hsm_progress(exp, karg);
		goto out;
	case LL_IOC_HSM_STATE_GET:
		rc = mdc_ioc_hsm_state_get(exp, karg);
		goto out;
	case LL_IOC_HSM_STATE_SET:
		rc = mdc_ioc_hsm_state_set(exp, karg);
		goto out;
	case LL_IOC_HSM_ACTION:
		rc = mdc_ioc_hsm_current_action(exp, karg);
		goto out;
	case LL_IOC_HSM_REQUEST:
		rc = mdc_ioc_hsm_request(exp, karg);
		goto out;
	case OBD_IOC_CLIENT_RECOVER:
		rc = ptlrpc_recover_import(imp, data->ioc_inlbuf1, 0);
		if (rc < 0)
			goto out;
		rc = 0;
		goto out;
	case IOC_OSC_SET_ACTIVE:
		rc = ptlrpc_set_import_active(imp, data->ioc_offset);
		goto out;
	case OBD_IOC_POLL_QUOTACHECK:
		rc = mdc_quota_poll_check(exp, (struct if_quotacheck *)karg);
		goto out;
	case OBD_IOC_PING_TARGET:
		rc = ptlrpc_obd_ping(obd);
		goto out;
	/*
	 * Normally IOC_OBD_STATFS, OBD_IOC_QUOTACTL iocontrol are handled by
	 * LMV instead of MDC. But when the cluster is upgraded from 1.8,
	 * there'd be no LMV layer thus we might be called here. Eventually
	 * this code should be removed.
	 * bz20731, LU-592.
	 */
	case IOC_OBD_STATFS: {
		struct obd_statfs stat_buf = {0};

		if (*((__u32 *)data->ioc_inlbuf2) != 0) {
			rc = -ENODEV;
			goto out;
		}

		/* copy UUID */
		if (copy_to_user(data->ioc_pbuf2, obd2cli_tgt(obd),
				 min_t(size_t, data->ioc_plen2,
				       sizeof(struct obd_uuid)))) {
			rc = -EFAULT;
			goto out;
		}

		rc = mdc_statfs(NULL, obd->obd_self_export, &stat_buf,
				cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS),
				0);
		if (rc != 0)
			goto out;

		if (copy_to_user(data->ioc_pbuf1, &stat_buf,
				 min_t(size_t, data->ioc_plen1,
				       sizeof(stat_buf)))) {
			rc = -EFAULT;
			goto out;
		}

		rc = 0;
		goto out;
	}
	case OBD_IOC_QUOTACTL: {
		struct if_quotactl *qctl = karg;
		struct obd_quotactl *oqctl;

		oqctl = kzalloc(sizeof(*oqctl), GFP_NOFS);
		if (!oqctl) {
			rc = -ENOMEM;
			goto out;
		}

		QCTL_COPY(oqctl, qctl);
		rc = obd_quotactl(exp, oqctl);
		if (rc == 0) {
			QCTL_COPY(qctl, oqctl);
			qctl->qc_valid = QC_MDTIDX;
			qctl->obd_uuid = obd->u.cli.cl_target_uuid;
		}

		kfree(oqctl);
		goto out;
	}
	case LL_IOC_GET_CONNECT_FLAGS:
		if (copy_to_user(uarg, exp_connect_flags_ptr(exp),
				 sizeof(*exp_connect_flags_ptr(exp)))) {
			rc = -EFAULT;
			goto out;
		}

		rc = 0;
		goto out;
	case LL_IOC_LOV_SWAP_LAYOUTS:
		rc = mdc_ioc_swap_layouts(exp, karg);
		goto out;
	default:
		CERROR("unrecognised ioctl: cmd = %#x\n", cmd);
		rc = -ENOTTY;
		goto out;
	}
out:
	module_put(THIS_MODULE);

	return rc;
}

static int mdc_get_info_rpc(struct obd_export *exp,
			    u32 keylen, void *key,
			    int vallen, void *val)
{
	struct obd_import      *imp = class_exp2cliimp(exp);
	struct ptlrpc_request  *req;
	char		   *tmp;
	int		     rc = -EINVAL;

	req = ptlrpc_request_alloc(imp, &RQF_MDS_GET_INFO);
	if (!req)
		return -ENOMEM;

	req_capsule_set_size(&req->rq_pill, &RMF_GETINFO_KEY,
			     RCL_CLIENT, keylen);
	req_capsule_set_size(&req->rq_pill, &RMF_GETINFO_VALLEN,
			     RCL_CLIENT, sizeof(__u32));

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_GET_INFO);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	tmp = req_capsule_client_get(&req->rq_pill, &RMF_GETINFO_KEY);
	memcpy(tmp, key, keylen);
	tmp = req_capsule_client_get(&req->rq_pill, &RMF_GETINFO_VALLEN);
	memcpy(tmp, &vallen, sizeof(__u32));

	req_capsule_set_size(&req->rq_pill, &RMF_GETINFO_VAL,
			     RCL_SERVER, vallen);
	ptlrpc_request_set_replen(req);

	rc = ptlrpc_queue_wait(req);
	/* -EREMOTE means the get_info result is partial, and it needs to
	 * continue on another MDT, see fid2path part in lmv_iocontrol
	 */
	if (rc == 0 || rc == -EREMOTE) {
		tmp = req_capsule_server_get(&req->rq_pill, &RMF_GETINFO_VAL);
		memcpy(val, tmp, vallen);
		if (ptlrpc_rep_need_swab(req)) {
			if (KEY_IS(KEY_FID2PATH))
				lustre_swab_fid2path(val);
		}
	}
	ptlrpc_req_finished(req);

	return rc;
}

static void lustre_swab_hai(struct hsm_action_item *h)
{
	__swab32s(&h->hai_len);
	__swab32s(&h->hai_action);
	lustre_swab_lu_fid(&h->hai_fid);
	lustre_swab_lu_fid(&h->hai_dfid);
	__swab64s(&h->hai_cookie);
	__swab64s(&h->hai_extent.offset);
	__swab64s(&h->hai_extent.length);
	__swab64s(&h->hai_gid);
}

static void lustre_swab_hal(struct hsm_action_list *h)
{
	struct hsm_action_item	*hai;
	u32 i;

	__swab32s(&h->hal_version);
	__swab32s(&h->hal_count);
	__swab32s(&h->hal_archive_id);
	__swab64s(&h->hal_flags);
	hai = hai_first(h);
	for (i = 0; i < h->hal_count; i++, hai = hai_next(hai))
		lustre_swab_hai(hai);
}

static void lustre_swab_kuch(struct kuc_hdr *l)
{
	__swab16s(&l->kuc_magic);
	/* __u8 l->kuc_transport */
	__swab16s(&l->kuc_msgtype);
	__swab16s(&l->kuc_msglen);
}

static int mdc_ioc_hsm_ct_start(struct obd_export *exp,
				struct lustre_kernelcomm *lk)
{
	struct obd_import  *imp = class_exp2cliimp(exp);
	__u32		    archive = lk->lk_data;
	int		    rc = 0;

	if (lk->lk_group != KUC_GRP_HSM) {
		CERROR("Bad copytool group %d\n", lk->lk_group);
		return -EINVAL;
	}

	CDEBUG(D_HSM, "CT start r%d w%d u%d g%d f%#x\n", lk->lk_rfd, lk->lk_wfd,
	       lk->lk_uid, lk->lk_group, lk->lk_flags);

	if (lk->lk_flags & LK_FLG_STOP) {
		/* Unregister with the coordinator */
		rc = mdc_ioc_hsm_ct_unregister(imp);
	} else {
		rc = mdc_ioc_hsm_ct_register(imp, archive);
	}

	return rc;
}

/**
 * Send a message to any listening copytools
 * @param val KUC message (kuc_hdr + hsm_action_list)
 * @param len total length of message
 */
static int mdc_hsm_copytool_send(size_t len, void *val)
{
	struct kuc_hdr		*lh = (struct kuc_hdr *)val;
	struct hsm_action_list	*hal = (struct hsm_action_list *)(lh + 1);

	if (len < sizeof(*lh) + sizeof(*hal)) {
		CERROR("Short HSM message %zu < %zu\n", len,
		       sizeof(*lh) + sizeof(*hal));
		return -EPROTO;
	}
	if (lh->kuc_magic == __swab16(KUC_MAGIC)) {
		lustre_swab_kuch(lh);
		lustre_swab_hal(hal);
	} else if (lh->kuc_magic != KUC_MAGIC) {
		CERROR("Bad magic %x!=%x\n", lh->kuc_magic, KUC_MAGIC);
		return -EPROTO;
	}

	CDEBUG(D_HSM,
	       "Received message mg=%x t=%d m=%d l=%d actions=%d on %s\n",
	       lh->kuc_magic, lh->kuc_transport, lh->kuc_msgtype,
	       lh->kuc_msglen, hal->hal_count, hal->hal_fsname);

	/* Broadcast to HSM listeners */
	return libcfs_kkuc_group_put(KUC_GRP_HSM, lh);
}

/**
 * callback function passed to kuc for re-registering each HSM copytool
 * running on MDC, after MDT shutdown/recovery.
 * @param data copytool registration data
 * @param cb_arg callback argument (obd_import)
 */
static int mdc_hsm_ct_reregister(void *data, void *cb_arg)
{
	struct kkuc_ct_data	*kcd = data;
	struct obd_import	*imp = (struct obd_import *)cb_arg;
	int			 rc;

	if (!kcd || kcd->kcd_magic != KKUC_CT_DATA_MAGIC)
		return -EPROTO;

	if (!obd_uuid_equals(&kcd->kcd_uuid, &imp->imp_obd->obd_uuid))
		return 0;

	CDEBUG(D_HA, "%s: recover copytool registration to MDT (archive=%#x)\n",
	       imp->imp_obd->obd_name, kcd->kcd_archive);
	rc = mdc_ioc_hsm_ct_register(imp, kcd->kcd_archive);

	/* ignore error if the copytool is already registered */
	return (rc == -EEXIST) ? 0 : rc;
}

static int mdc_set_info_async(const struct lu_env *env,
			      struct obd_export *exp,
			      u32 keylen, void *key,
			      u32 vallen, void *val,
			      struct ptlrpc_request_set *set)
{
	struct obd_import	*imp = class_exp2cliimp(exp);
	int			 rc;

	if (KEY_IS(KEY_READ_ONLY)) {
		if (vallen != sizeof(int))
			return -EINVAL;

		spin_lock(&imp->imp_lock);
		if (*((int *)val)) {
			imp->imp_connect_flags_orig |= OBD_CONNECT_RDONLY;
			imp->imp_connect_data.ocd_connect_flags |=
							OBD_CONNECT_RDONLY;
		} else {
			imp->imp_connect_flags_orig &= ~OBD_CONNECT_RDONLY;
			imp->imp_connect_data.ocd_connect_flags &=
							~OBD_CONNECT_RDONLY;
		}
		spin_unlock(&imp->imp_lock);

		return do_set_info_async(imp, MDS_SET_INFO, LUSTRE_MDS_VERSION,
					 keylen, key, vallen, val, set);
	}
	if (KEY_IS(KEY_SPTLRPC_CONF)) {
		sptlrpc_conf_client_adapt(exp->exp_obd);
		return 0;
	}
	if (KEY_IS(KEY_FLUSH_CTX)) {
		sptlrpc_import_flush_my_ctx(imp);
		return 0;
	}
	if (KEY_IS(KEY_CHANGELOG_CLEAR)) {
		rc = do_set_info_async(imp, MDS_SET_INFO, LUSTRE_MDS_VERSION,
				       keylen, key, vallen, val, set);
		return rc;
	}
	if (KEY_IS(KEY_HSM_COPYTOOL_SEND)) {
		rc = mdc_hsm_copytool_send(vallen, val);
		return rc;
	}
	if (KEY_IS(KEY_DEFAULT_EASIZE)) {
		u32 *default_easize = val;

		exp->exp_obd->u.cli.cl_default_mds_easize = *default_easize;
		return 0;
	}

	CERROR("Unknown key %s\n", (char *)key);
	return -EINVAL;
}

static int mdc_get_info(const struct lu_env *env, struct obd_export *exp,
			__u32 keylen, void *key, __u32 *vallen, void *val,
			struct lov_stripe_md *lsm)
{
	int rc = -EINVAL;

	if (KEY_IS(KEY_MAX_EASIZE)) {
		u32 mdsize, *max_easize;

		if (*vallen != sizeof(int))
			return -EINVAL;
		mdsize = *(u32 *)val;
		if (mdsize > exp->exp_obd->u.cli.cl_max_mds_easize)
			exp->exp_obd->u.cli.cl_max_mds_easize = mdsize;
		max_easize = val;
		*max_easize = exp->exp_obd->u.cli.cl_max_mds_easize;
		return 0;
	} else if (KEY_IS(KEY_DEFAULT_EASIZE)) {
		u32 *default_easize;

		if (*vallen != sizeof(int))
			return -EINVAL;
		default_easize = val;
		*default_easize = exp->exp_obd->u.cli.cl_default_mds_easize;
		return 0;
	} else if (KEY_IS(KEY_CONN_DATA)) {
		struct obd_import *imp = class_exp2cliimp(exp);
		struct obd_connect_data *data = val;

		if (*vallen != sizeof(*data))
			return -EINVAL;

		*data = imp->imp_connect_data;
		return 0;
	} else if (KEY_IS(KEY_TGT_COUNT)) {
		*((u32 *)val) = 1;
		return 0;
	}

	rc = mdc_get_info_rpc(exp, keylen, key, *vallen, val);

	return rc;
}

static int mdc_sync(struct obd_export *exp, const struct lu_fid *fid,
		    struct ptlrpc_request **request)
{
	struct ptlrpc_request *req;
	int		    rc;

	*request = NULL;
	req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_MDS_SYNC);
	if (!req)
		return -ENOMEM;

	rc = ptlrpc_request_pack(req, LUSTRE_MDS_VERSION, MDS_SYNC);
	if (rc) {
		ptlrpc_request_free(req);
		return rc;
	}

	mdc_pack_body(req, fid, 0, 0, -1, 0);

	ptlrpc_request_set_replen(req);

	rc = ptlrpc_queue_wait(req);
	if (rc)
		ptlrpc_req_finished(req);
	else
		*request = req;
	return rc;
}

static int mdc_import_event(struct obd_device *obd, struct obd_import *imp,
			    enum obd_import_event event)
{
	int rc = 0;

	LASSERT(imp->imp_obd == obd);

	switch (event) {
	case IMP_EVENT_DISCON: {
#if 0
		/* XXX Pass event up to OBDs stack. used only for FLD now */
		rc = obd_notify_observer(obd, obd, OBD_NOTIFY_DISCON, NULL);
#endif
		break;
	}
	case IMP_EVENT_INACTIVE: {
		struct client_obd *cli = &obd->u.cli;
		/*
		 * Flush current sequence to make client obtain new one
		 * from server in case of disconnect/reconnect.
		 */
		if (cli->cl_seq)
			seq_client_flush(cli->cl_seq);

		rc = obd_notify_observer(obd, obd, OBD_NOTIFY_INACTIVE, NULL);
		break;
	}
	case IMP_EVENT_INVALIDATE: {
		struct ldlm_namespace *ns = obd->obd_namespace;

		ldlm_namespace_cleanup(ns, LDLM_FL_LOCAL_ONLY);

		break;
	}
	case IMP_EVENT_ACTIVE:
		rc = obd_notify_observer(obd, obd, OBD_NOTIFY_ACTIVE, NULL);
		/* redo the kuc registration after reconnecting */
		if (rc == 0)
			/* re-register HSM agents */
			rc = libcfs_kkuc_group_foreach(KUC_GRP_HSM,
						       mdc_hsm_ct_reregister,
						       (void *)imp);
		break;
	case IMP_EVENT_OCD:
		rc = obd_notify_observer(obd, obd, OBD_NOTIFY_OCD, NULL);
		break;
	case IMP_EVENT_DEACTIVATE:
	case IMP_EVENT_ACTIVATE:
		break;
	default:
		CERROR("Unknown import event %x\n", event);
		LBUG();
	}
	return rc;
}

int mdc_fid_alloc(const struct lu_env *env, struct obd_export *exp,
		  struct lu_fid *fid, struct md_op_data *op_data)
{
	struct client_obd *cli = &exp->exp_obd->u.cli;
	struct lu_client_seq *seq = cli->cl_seq;

	return seq_client_alloc_fid(env, seq, fid);
}

static struct obd_uuid *mdc_get_uuid(struct obd_export *exp)
{
	struct client_obd *cli = &exp->exp_obd->u.cli;

	return &cli->cl_target_uuid;
}

/**
 * Determine whether the lock can be canceled before replaying it during
 * recovery, non zero value will be return if the lock can be canceled,
 * or zero returned for not
 */
static int mdc_cancel_weight(struct ldlm_lock *lock)
{
	if (lock->l_resource->lr_type != LDLM_IBITS)
		return 0;

	/* FIXME: if we ever get into a situation where there are too many
	 * opened files with open locks on a single node, then we really
	 * should replay these open locks to reget it
	 */
	if (lock->l_policy_data.l_inodebits.bits & MDS_INODELOCK_OPEN)
		return 0;

	return 1;
}

static int mdc_resource_inode_free(struct ldlm_resource *res)
{
	if (res->lr_lvb_inode)
		res->lr_lvb_inode = NULL;

	return 0;
}

static struct ldlm_valblock_ops inode_lvbo = {
	.lvbo_free = mdc_resource_inode_free,
};

static int mdc_llog_init(struct obd_device *obd)
{
	struct obd_llog_group	*olg = &obd->obd_olg;
	struct llog_ctxt	*ctxt;
	int			 rc;

	rc = llog_setup(NULL, obd, olg, LLOG_CHANGELOG_REPL_CTXT, obd,
			&llog_client_ops);
	if (rc)
		return rc;

	ctxt = llog_group_get_ctxt(olg, LLOG_CHANGELOG_REPL_CTXT);
	llog_initiator_connect(ctxt);
	llog_ctxt_put(ctxt);

	return 0;
}

static void mdc_llog_finish(struct obd_device *obd)
{
	struct llog_ctxt *ctxt;

	ctxt = llog_get_context(obd, LLOG_CHANGELOG_REPL_CTXT);
	if (ctxt)
		llog_cleanup(NULL, ctxt);
}

static int mdc_setup(struct obd_device *obd, struct lustre_cfg *cfg)
{
	struct client_obd *cli = &obd->u.cli;
	struct lprocfs_static_vars lvars = { NULL };
	int rc;

	cli->cl_rpc_lock = kzalloc(sizeof(*cli->cl_rpc_lock), GFP_NOFS);
	if (!cli->cl_rpc_lock)
		return -ENOMEM;
	mdc_init_rpc_lock(cli->cl_rpc_lock);

	rc = ptlrpcd_addref();
	if (rc < 0)
		goto err_rpc_lock;

	cli->cl_close_lock = kzalloc(sizeof(*cli->cl_close_lock), GFP_NOFS);
	if (!cli->cl_close_lock) {
		rc = -ENOMEM;
		goto err_ptlrpcd_decref;
	}
	mdc_init_rpc_lock(cli->cl_close_lock);

	rc = client_obd_setup(obd, cfg);
	if (rc)
		goto err_close_lock;
	lprocfs_mdc_init_vars(&lvars);
	lprocfs_obd_setup(obd, lvars.obd_vars, lvars.sysfs_vars);
	sptlrpc_lprocfs_cliobd_attach(obd);
	ptlrpc_lprocfs_register_obd(obd);

	ns_register_cancel(obd->obd_namespace, mdc_cancel_weight);

	obd->obd_namespace->ns_lvbo = &inode_lvbo;

	rc = mdc_llog_init(obd);
	if (rc) {
		mdc_cleanup(obd);
		CERROR("failed to setup llogging subsystems\n");
	}

	return rc;

err_close_lock:
	kfree(cli->cl_close_lock);
err_ptlrpcd_decref:
	ptlrpcd_decref();
err_rpc_lock:
	kfree(cli->cl_rpc_lock);
	return rc;
}

/* Initialize the default and maximum LOV EA and cookie sizes.  This allows
 * us to make MDS RPCs with large enough reply buffers to hold a default
 * sized EA and cookie without having to calculate this (via a call into the
 * LOV + OSCs) each time we make an RPC.  The maximum size is also tracked
 * but not used to avoid wastefully vmalloc()'ing large reply buffers when
 * a large number of stripes is possible.  If a larger reply buffer is
 * required it will be reallocated in the ptlrpc layer due to overflow.
 */
static int mdc_init_ea_size(struct obd_export *exp, u32 easize, u32 def_easize,
			    u32 cookiesize, u32 def_cookiesize)
{
	struct obd_device *obd = exp->exp_obd;
	struct client_obd *cli = &obd->u.cli;

	if (cli->cl_max_mds_easize < easize)
		cli->cl_max_mds_easize = easize;

	if (cli->cl_default_mds_easize < def_easize)
		cli->cl_default_mds_easize = def_easize;

	if (cli->cl_max_mds_cookiesize < cookiesize)
		cli->cl_max_mds_cookiesize = cookiesize;

	if (cli->cl_default_mds_cookiesize < def_cookiesize)
		cli->cl_default_mds_cookiesize = def_cookiesize;

	return 0;
}

static int mdc_precleanup(struct obd_device *obd, enum obd_cleanup_stage stage)
{
	switch (stage) {
	case OBD_CLEANUP_EARLY:
		break;
	case OBD_CLEANUP_EXPORTS:
		/* Failsafe, ok if racy */
		if (obd->obd_type->typ_refcnt <= 1)
			libcfs_kkuc_group_rem(0, KUC_GRP_HSM);

		obd_cleanup_client_import(obd);
		ptlrpc_lprocfs_unregister_obd(obd);
		lprocfs_obd_cleanup(obd);

		mdc_llog_finish(obd);
		break;
	}
	return 0;
}

static int mdc_cleanup(struct obd_device *obd)
{
	struct client_obd *cli = &obd->u.cli;

	kfree(cli->cl_rpc_lock);
	kfree(cli->cl_close_lock);

	ptlrpcd_decref();

	return client_obd_cleanup(obd);
}

static int mdc_process_config(struct obd_device *obd, u32 len, void *buf)
{
	struct lustre_cfg *lcfg = buf;
	struct lprocfs_static_vars lvars = { NULL };
	int rc = 0;

	lprocfs_mdc_init_vars(&lvars);
	switch (lcfg->lcfg_command) {
	default:
		rc = class_process_proc_param(PARAM_MDC, lvars.obd_vars,
					      lcfg, obd);
		if (rc > 0)
			rc = 0;
		break;
	}
	return rc;
}

static struct obd_ops mdc_obd_ops = {
	.owner          = THIS_MODULE,
	.setup          = mdc_setup,
	.precleanup     = mdc_precleanup,
	.cleanup        = mdc_cleanup,
	.add_conn       = client_import_add_conn,
	.del_conn       = client_import_del_conn,
	.connect        = client_connect_import,
	.disconnect     = client_disconnect_export,
	.iocontrol      = mdc_iocontrol,
	.set_info_async = mdc_set_info_async,
	.statfs         = mdc_statfs,
	.fid_init       = client_fid_init,
	.fid_fini       = client_fid_fini,
	.fid_alloc      = mdc_fid_alloc,
	.import_event   = mdc_import_event,
	.get_info       = mdc_get_info,
	.process_config = mdc_process_config,
	.get_uuid       = mdc_get_uuid,
	.quotactl       = mdc_quotactl,
	.quotacheck     = mdc_quotacheck
};

static struct md_ops mdc_md_ops = {
	.getstatus		= mdc_getstatus,
	.null_inode		= mdc_null_inode,
	.close			= mdc_close,
	.create			= mdc_create,
	.done_writing		= mdc_done_writing,
	.enqueue		= mdc_enqueue,
	.getattr		= mdc_getattr,
	.getattr_name		= mdc_getattr_name,
	.intent_lock		= mdc_intent_lock,
	.link			= mdc_link,
	.rename			= mdc_rename,
	.setattr		= mdc_setattr,
	.setxattr		= mdc_setxattr,
	.getxattr		= mdc_getxattr,
	.sync			= mdc_sync,
	.read_page		= mdc_read_page,
	.unlink			= mdc_unlink,
	.cancel_unused		= mdc_cancel_unused,
	.init_ea_size		= mdc_init_ea_size,
	.set_lock_data		= mdc_set_lock_data,
	.lock_match		= mdc_lock_match,
	.get_lustre_md		= mdc_get_lustre_md,
	.free_lustre_md		= mdc_free_lustre_md,
	.set_open_replay_data	= mdc_set_open_replay_data,
	.clear_open_replay_data	= mdc_clear_open_replay_data,
	.intent_getattr_async	= mdc_intent_getattr_async,
	.revalidate_lock	= mdc_revalidate_lock
};

static int __init mdc_init(void)
{
	struct lprocfs_static_vars lvars = { NULL };

	lprocfs_mdc_init_vars(&lvars);

	return class_register_type(&mdc_obd_ops, &mdc_md_ops,
				 LUSTRE_MDC_NAME, NULL);
}

static void /*__exit*/ mdc_exit(void)
{
	class_unregister_type(LUSTRE_MDC_NAME);
}

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

module_init(mdc_init);
module_exit(mdc_exit);