[fs/lustre-release.git] / lustre / mdt / mdt_handler.c

/*
 * 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.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2010, 2013, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lustre/mdt/mdt_handler.c
 *
 * Lustre Metadata Target (mdt) request handler
 *
 * Author: Peter Braam <braam@clusterfs.com>
 * Author: Andreas Dilger <adilger@clusterfs.com>
 * Author: Phil Schwan <phil@clusterfs.com>
 * Author: Mike Shaver <shaver@clusterfs.com>
 * Author: Nikita Danilov <nikita@clusterfs.com>
 * Author: Huang Hua <huanghua@clusterfs.com>
 * Author: Yury Umanets <umka@clusterfs.com>
 */

#define DEBUG_SUBSYSTEM S_MDS

#include <linux/module.h>
/*
 * struct OBD_{ALLOC,FREE}*()
 */
#include <obd_support.h>
#include <lustre_ioctl.h>
/* struct ptlrpc_request */
#include <lustre_net.h>
/* struct obd_export */
#include <lustre_export.h>
/* struct obd_device */
#include <obd.h>
/* lu2dt_dev() */
#include <dt_object.h>
#include <lustre_mds.h>
#include <lustre_log.h>
#include "mdt_internal.h"
#include <lustre_acl.h>
#include <lustre_param.h>
#include <lustre_quota.h>
#include <lustre_lfsck.h>

mdl_mode_t mdt_mdl_lock_modes[] = {
        [LCK_MINMODE] = MDL_MINMODE,
        [LCK_EX]      = MDL_EX,
        [LCK_PW]      = MDL_PW,
        [LCK_PR]      = MDL_PR,
        [LCK_CW]      = MDL_CW,
        [LCK_CR]      = MDL_CR,
        [LCK_NL]      = MDL_NL,
        [LCK_GROUP]   = MDL_GROUP
};

ldlm_mode_t mdt_dlm_lock_modes[] = {
        [MDL_MINMODE] = LCK_MINMODE,
        [MDL_EX]      = LCK_EX,
        [MDL_PW]      = LCK_PW,
        [MDL_PR]      = LCK_PR,
        [MDL_CW]      = LCK_CW,
        [MDL_CR]      = LCK_CR,
        [MDL_NL]      = LCK_NL,
        [MDL_GROUP]   = LCK_GROUP
};

static struct mdt_device *mdt_dev(struct lu_device *d);
static int mdt_unpack_req_pack_rep(struct mdt_thread_info *info, __u32 flags);

static const struct lu_object_operations mdt_obj_ops;

/* Slab for MDT object allocation */
static struct kmem_cache *mdt_object_kmem;

/* For HSM restore handles */
struct kmem_cache *mdt_hsm_cdt_kmem;

/* For HSM request handles */
struct kmem_cache *mdt_hsm_car_kmem;

static struct lu_kmem_descr mdt_caches[] = {
        {
                .ckd_cache = &mdt_object_kmem,
                .ckd_name  = "mdt_obj",
                .ckd_size  = sizeof(struct mdt_object)
        },
        {
                .ckd_cache      = &mdt_hsm_cdt_kmem,
                .ckd_name       = "mdt_cdt_restore_handle",
                .ckd_size       = sizeof(struct cdt_restore_handle)
        },
        {
                .ckd_cache      = &mdt_hsm_car_kmem,
                .ckd_name       = "mdt_cdt_agent_req",
                .ckd_size       = sizeof(struct cdt_agent_req)
        },
        {
                .ckd_cache = NULL
        }
};

int mdt_get_disposition(struct ldlm_reply *rep, int flag)
{
        if (!rep)
                return 0;
        return (rep->lock_policy_res1 & flag);
}

void mdt_clear_disposition(struct mdt_thread_info *info,
                           struct ldlm_reply *rep, int flag)
{
        if (info) {
                info->mti_opdata &= ~flag;
                tgt_opdata_clear(info->mti_env, flag);
        }
        if (rep)
                rep->lock_policy_res1 &= ~flag;
}

void mdt_set_disposition(struct mdt_thread_info *info,
                         struct ldlm_reply *rep, int flag)
{
        if (info) {
                info->mti_opdata |= flag;
                tgt_opdata_set(info->mti_env, flag);
        }
        if (rep)
                rep->lock_policy_res1 |= flag;
}

void mdt_lock_reg_init(struct mdt_lock_handle *lh, ldlm_mode_t lm)
{
        lh->mlh_pdo_hash = 0;
        lh->mlh_reg_mode = lm;
        lh->mlh_rreg_mode = lm;
        lh->mlh_type = MDT_REG_LOCK;
}

void mdt_lock_pdo_init(struct mdt_lock_handle *lh, ldlm_mode_t lock_mode,
                       const struct lu_name *lname)
{
        lh->mlh_reg_mode = lock_mode;
        lh->mlh_rreg_mode = lock_mode;
        lh->mlh_type = MDT_PDO_LOCK;

        if (lu_name_is_valid(lname)) {
                lh->mlh_pdo_hash = full_name_hash(lname->ln_name,
                                                  lname->ln_namelen);
                /* XXX Workaround for LU-2856
                 *
                 * Zero is a valid return value of full_name_hash, but
                 * several users of mlh_pdo_hash assume a non-zero
                 * hash value. We therefore map zero onto an
                 * arbitrary, but consistent value (1) to avoid
                 * problems further down the road. */
                if (unlikely(lh->mlh_pdo_hash == 0))
                        lh->mlh_pdo_hash = 1;
        } else {
                lh->mlh_pdo_hash = 0;
        }
}

static void mdt_lock_pdo_mode(struct mdt_thread_info *info, struct mdt_object *o,
                              struct mdt_lock_handle *lh)
{
        mdl_mode_t mode;
        ENTRY;

        /*
         * Any dir access needs couple of locks:
         *
         * 1) on part of dir we gonna take lookup/modify;
         *
         * 2) on whole dir to protect it from concurrent splitting and/or to
         * flush client's cache for readdir().
         *
         * so, for a given mode and object this routine decides what lock mode
         * to use for lock #2:
         *
         * 1) if caller's gonna lookup in dir then we need to protect dir from
         * being splitted only - LCK_CR
         *
         * 2) if caller's gonna modify dir then we need to protect dir from
         * being splitted and to flush cache - LCK_CW
         *
         * 3) if caller's gonna modify dir and that dir seems ready for
         * splitting then we need to protect it from any type of access
         * (lookup/modify/split) - LCK_EX --bzzz
         */

        LASSERT(lh->mlh_reg_mode != LCK_MINMODE);
        LASSERT(lh->mlh_pdo_mode == LCK_MINMODE);

        /*
         * Ask underlaying level its opinion about preferable PDO lock mode
         * having access type passed as regular lock mode:
         *
         * - MDL_MINMODE means that lower layer does not want to specify lock
         * mode;
         *
         * - MDL_NL means that no PDO lock should be taken. This is used in some
         * cases. Say, for non-splittable directories no need to use PDO locks
         * at all.
         */
        mode = mdo_lock_mode(info->mti_env, mdt_object_child(o),
                             mdt_dlm_mode2mdl_mode(lh->mlh_reg_mode));

        if (mode != MDL_MINMODE) {
                lh->mlh_pdo_mode = mdt_mdl_mode2dlm_mode(mode);
        } else {
                /*
                 * Lower layer does not want to specify locking mode. We do it
                 * our selves. No special protection is needed, just flush
                 * client's cache on modification and allow concurrent
                 * mondification.
                 */
                switch (lh->mlh_reg_mode) {
                case LCK_EX:
                        lh->mlh_pdo_mode = LCK_EX;
                        break;
                case LCK_PR:
                        lh->mlh_pdo_mode = LCK_CR;
                        break;
                case LCK_PW:
                        lh->mlh_pdo_mode = LCK_CW;
                        break;
                default:
                        CERROR("Not expected lock type (0x%x)\n",
                               (int)lh->mlh_reg_mode);
                        LBUG();
                }
        }

        LASSERT(lh->mlh_pdo_mode != LCK_MINMODE);
        EXIT;
}

static int mdt_getstatus(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info = tsi2mdt_info(tsi);
        struct mdt_device       *mdt = info->mti_mdt;
        struct mdt_body         *repbody;
        int                      rc;

        ENTRY;

        rc = mdt_check_ucred(info);
        if (rc)
                GOTO(out, rc = err_serious(rc));

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_GETSTATUS_PACK))
                GOTO(out, rc = err_serious(-ENOMEM));

        repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
        repbody->fid1 = mdt->mdt_md_root_fid;
        repbody->valid |= OBD_MD_FLID;

        if (tsi->tsi_tgt->lut_mds_capa &&
            exp_connect_flags(info->mti_exp) & OBD_CONNECT_MDS_CAPA) {
                struct mdt_object       *root;
                struct lustre_capa      *capa;

                root = mdt_object_find(info->mti_env, mdt, &repbody->fid1);
                if (IS_ERR(root))
                        GOTO(out, rc = PTR_ERR(root));

                capa = req_capsule_server_get(info->mti_pill, &RMF_CAPA1);
                LASSERT(capa);
                capa->lc_opc = CAPA_OPC_MDS_DEFAULT;
                rc = mo_capa_get(info->mti_env, mdt_object_child(root), capa,
                                 0);
                mdt_object_put(info->mti_env, root);
                if (rc == 0)
                        repbody->valid |= OBD_MD_FLMDSCAPA;
        }
        EXIT;
out:
        mdt_thread_info_fini(info);
        return rc;
}

static int mdt_statfs(struct tgt_session_info *tsi)
{
        struct ptlrpc_request           *req = tgt_ses_req(tsi);
        struct mdt_thread_info          *info = tsi2mdt_info(tsi);
        struct md_device                *next = info->mti_mdt->mdt_child;
        struct ptlrpc_service_part      *svcpt;
        struct obd_statfs               *osfs;
        int                             rc;

        ENTRY;

        svcpt = req->rq_rqbd->rqbd_svcpt;

        /* This will trigger a watchdog timeout */
        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_STATFS_LCW_SLEEP,
                         (MDT_SERVICE_WATCHDOG_FACTOR *
                          at_get(&svcpt->scp_at_estimate)) + 1);

        rc = mdt_check_ucred(info);
        if (rc)
                GOTO(out, rc = err_serious(rc));

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_STATFS_PACK))
                GOTO(out, rc = err_serious(-ENOMEM));

        osfs = req_capsule_server_get(info->mti_pill, &RMF_OBD_STATFS);
        if (!osfs)
                GOTO(out, rc = -EPROTO);

        /** statfs information are cached in the mdt_device */
        if (cfs_time_before_64(info->mti_mdt->mdt_osfs_age,
                               cfs_time_shift_64(-OBD_STATFS_CACHE_SECONDS))) {
                /** statfs data is too old, get up-to-date one */
                rc = next->md_ops->mdo_statfs(info->mti_env, next, osfs);
                if (rc)
                        GOTO(out, rc);
                spin_lock(&info->mti_mdt->mdt_osfs_lock);
                info->mti_mdt->mdt_osfs = *osfs;
                info->mti_mdt->mdt_osfs_age = cfs_time_current_64();
                spin_unlock(&info->mti_mdt->mdt_osfs_lock);
        } else {
                /** use cached statfs data */
                spin_lock(&info->mti_mdt->mdt_osfs_lock);
                *osfs = info->mti_mdt->mdt_osfs;
                spin_unlock(&info->mti_mdt->mdt_osfs_lock);
        }

        if (rc == 0)
                mdt_counter_incr(req, LPROC_MDT_STATFS);
out:
        mdt_thread_info_fini(info);
        RETURN(rc);
}

/**
 * Pack SOM attributes into the reply.
 * Call under a DLM UPDATE lock.
 */
static void mdt_pack_size2body(struct mdt_thread_info *info,
                               struct mdt_object *mo)
{
        struct mdt_body *b;
        struct md_attr *ma = &info->mti_attr;

        LASSERT(ma->ma_attr.la_valid & LA_MODE);
        b = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);

        /* Check if Size-on-MDS is supported, if this is a regular file,
         * if SOM is enabled on the object and if SOM cache exists and valid.
         * Otherwise do not pack Size-on-MDS attributes to the reply. */
        if (!(mdt_conn_flags(info) & OBD_CONNECT_SOM) ||
            !S_ISREG(ma->ma_attr.la_mode) ||
            !mdt_object_is_som_enabled(mo) ||
            !(ma->ma_valid & MA_SOM))
                return;

        b->valid |= OBD_MD_FLSIZE | OBD_MD_FLBLOCKS;
        b->size = ma->ma_som->msd_size;
        b->blocks = ma->ma_som->msd_blocks;
}

void mdt_pack_attr2body(struct mdt_thread_info *info, struct mdt_body *b,
                        const struct lu_attr *attr, const struct lu_fid *fid)
{
        struct md_attr *ma = &info->mti_attr;

        LASSERT(ma->ma_valid & MA_INODE);

        b->atime      = attr->la_atime;
        b->mtime      = attr->la_mtime;
        b->ctime      = attr->la_ctime;
        b->mode       = attr->la_mode;
        b->size       = attr->la_size;
        b->blocks     = attr->la_blocks;
        b->uid        = attr->la_uid;
        b->gid        = attr->la_gid;
        b->flags      = attr->la_flags;
        b->nlink      = attr->la_nlink;
        b->rdev       = attr->la_rdev;

        /*XXX should pack the reply body according to lu_valid*/
        b->valid |= OBD_MD_FLCTIME | OBD_MD_FLUID   |
                    OBD_MD_FLGID   | OBD_MD_FLTYPE  |
                    OBD_MD_FLMODE  | OBD_MD_FLNLINK | OBD_MD_FLFLAGS |
                    OBD_MD_FLATIME | OBD_MD_FLMTIME ;

        if (!S_ISREG(attr->la_mode)) {
                b->valid |= OBD_MD_FLSIZE | OBD_MD_FLBLOCKS | OBD_MD_FLRDEV;
        } else if (ma->ma_need & MA_LOV && !(ma->ma_valid & MA_LOV)) {
                /* means no objects are allocated on osts. */
                LASSERT(!(ma->ma_valid & MA_LOV));
                /* just ignore blocks occupied by extend attributes on MDS */
                b->blocks = 0;
                /* if no object is allocated on osts, the size on mds is valid. b=22272 */
                b->valid |= OBD_MD_FLSIZE | OBD_MD_FLBLOCKS;
        } else if ((ma->ma_valid & MA_LOV) && ma->ma_lmm != NULL &&
                   ma->ma_lmm->lmm_pattern & LOV_PATTERN_F_RELEASED) {
                /* A released file stores its size on MDS. */
                /* But return 1 block for released file, unless tools like tar
                 * will consider it fully sparse. (LU-3864)
                 */
                if (unlikely(b->size == 0))
                        b->blocks = 0;
                else
                        b->blocks = 1;
                b->valid |= OBD_MD_FLSIZE | OBD_MD_FLBLOCKS;
        }

        if (fid) {
                b->fid1 = *fid;
                b->valid |= OBD_MD_FLID;
                CDEBUG(D_INODE, DFID": nlink=%d, mode=%o, size="LPU64"\n",
                                PFID(fid), b->nlink, b->mode, b->size);
        }

        if (info)
                mdt_body_reverse_idmap(info, b);

        if (fid != NULL && (b->valid & OBD_MD_FLSIZE))
                CDEBUG(D_VFSTRACE, DFID": returning size %llu\n",
                       PFID(fid), (unsigned long long)b->size);
}

static inline int mdt_body_has_lov(const struct lu_attr *la,
                                   const struct mdt_body *body)
{
        return ((S_ISREG(la->la_mode) && (body->valid & OBD_MD_FLEASIZE)) ||
                (S_ISDIR(la->la_mode) && (body->valid & OBD_MD_FLDIREA )) );
}

void mdt_client_compatibility(struct mdt_thread_info *info)
{
        struct mdt_body       *body;
        struct ptlrpc_request *req = mdt_info_req(info);
        struct obd_export     *exp = req->rq_export;
        struct md_attr        *ma = &info->mti_attr;
        struct lu_attr        *la = &ma->ma_attr;
        ENTRY;

        if (exp_connect_layout(exp))
                /* the client can deal with 16-bit lmm_stripe_count */
                RETURN_EXIT;

        body = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);

        if (!mdt_body_has_lov(la, body))
                RETURN_EXIT;

        /* now we have a reply with a lov for a client not compatible with the
         * layout lock so we have to clean the layout generation number */
        if (S_ISREG(la->la_mode))
                ma->ma_lmm->lmm_layout_gen = 0;
        EXIT;
}

int mdt_attr_get_eabuf_size(struct mdt_thread_info *info, struct mdt_object *o)
{
        const struct lu_env *env = info->mti_env;
        int rc, rc2;

        rc = mo_xattr_get(env, mdt_object_child(o), &LU_BUF_NULL,
                          XATTR_NAME_LOV);

        if (rc == -ENODATA)
                rc = 0;

        if (rc < 0)
                goto out;

        /* Is it a directory? Let's check for the LMV as well */
        if (S_ISDIR(lu_object_attr(&mdt_object_child(o)->mo_lu))) {
                rc2 = mo_xattr_get(env, mdt_object_child(o), &LU_BUF_NULL,
                                   XATTR_NAME_LMV);
                if ((rc2 < 0 && rc2 != -ENODATA) || (rc2 > rc))
                        rc = rc2;
        }

out:
        return rc;
}

int mdt_big_xattr_get(struct mdt_thread_info *info, struct mdt_object *o,
                      const char *name)
{
        const struct lu_env *env = info->mti_env;
        int rc;
        ENTRY;

        LASSERT(info->mti_big_lmm_used == 0);
        rc = mo_xattr_get(env, mdt_object_child(o), &LU_BUF_NULL, name);
        if (rc < 0)
                RETURN(rc);

        /* big_lmm may need to be grown */
        if (info->mti_big_lmmsize < rc) {
                int size = size_roundup_power2(rc);

                if (info->mti_big_lmmsize > 0) {
                        /* free old buffer */
                        LASSERT(info->mti_big_lmm);
                        OBD_FREE_LARGE(info->mti_big_lmm,
                                       info->mti_big_lmmsize);
                        info->mti_big_lmm = NULL;
                        info->mti_big_lmmsize = 0;
                }

                OBD_ALLOC_LARGE(info->mti_big_lmm, size);
                if (info->mti_big_lmm == NULL)
                        RETURN(-ENOMEM);
                info->mti_big_lmmsize = size;
        }
        LASSERT(info->mti_big_lmmsize >= rc);

        info->mti_buf.lb_buf = info->mti_big_lmm;
        info->mti_buf.lb_len = info->mti_big_lmmsize;
        rc = mo_xattr_get(env, mdt_object_child(o), &info->mti_buf, name);
        if (rc > 0)
                info->mti_big_lmm_used = 1;

        RETURN(rc);
}

int mdt_stripe_get(struct mdt_thread_info *info, struct mdt_object *o,
                   struct md_attr *ma, const char *name)
{
        struct md_object *next = mdt_object_child(o);
        struct lu_buf    *buf = &info->mti_buf;
        int rc;

        if (strcmp(name, XATTR_NAME_LOV) == 0) {
                buf->lb_buf = ma->ma_lmm;
                buf->lb_len = ma->ma_lmm_size;
                LASSERT(!(ma->ma_valid & MA_LOV));
        } else if (strcmp(name, XATTR_NAME_LMV) == 0) {
                buf->lb_buf = ma->ma_lmv;
                buf->lb_len = ma->ma_lmv_size;
                LASSERT(!(ma->ma_valid & MA_LMV));
        } else if (strcmp(name, XATTR_NAME_DEFAULT_LMV) == 0) {
                buf->lb_buf = ma->ma_lmv;
                buf->lb_len = ma->ma_lmv_size;
                LASSERT(!(ma->ma_valid & MA_LMV_DEF));
        } else {
                return -EINVAL;
        }

        rc = mo_xattr_get(info->mti_env, next, buf, name);
        if (rc > 0) {
                if (strcmp(name, XATTR_NAME_LOV) == 0) {
                        ma->ma_lmm_size = rc;
                        ma->ma_valid |= MA_LOV;
                } else if (strcmp(name, XATTR_NAME_LMV) == 0) {
                        ma->ma_lmv_size = rc;
                        ma->ma_valid |= MA_LMV;
                } else if (strcmp(name, XATTR_NAME_DEFAULT_LMV) == 0) {
                        ma->ma_lmv_size = rc;
                        ma->ma_valid |= MA_LMV_DEF;
                }

                rc = 0;
        } else if (rc == -ENODATA) {
                /* no LOV EA */
                rc = 0;
        } else if (rc == -ERANGE) {
                /* Default LMV has fixed size, so it must be able to fit
                 * in the original buffer */
                if (strcmp(name, XATTR_NAME_DEFAULT_LMV) == 0)
                        return rc;
                rc = mdt_big_xattr_get(info, o, name);
                if (rc > 0) {
                        if (!strcmp(name, XATTR_NAME_LOV)) {
                                ma->ma_valid |= MA_LOV;
                                ma->ma_lmm = info->mti_big_lmm;
                                ma->ma_lmm_size = rc;
                        } else if (!strcmp(name, XATTR_NAME_LMV)) {
                                ma->ma_valid |= MA_LMV;
                                ma->ma_lmv = info->mti_big_lmm;
                                ma->ma_lmv_size = rc;
                        } else {
                                return -EINVAL;
                        }

                        /* update mdt_max_mdsize so all clients
                         * will be aware about that */
                        if (info->mti_mdt->mdt_max_mdsize < rc)
                                info->mti_mdt->mdt_max_mdsize = rc;
                        rc = 0;
                }
        }

        return rc;
}

static int mdt_attr_get_pfid(struct mdt_thread_info *info,
                             struct mdt_object *o, struct lu_fid *pfid)
{
        struct lu_buf           *buf = &info->mti_buf;
        struct link_ea_header   *leh;
        struct link_ea_entry    *lee;
        int                      rc;
        ENTRY;

        buf->lb_buf = info->mti_big_lmm;
        buf->lb_len = info->mti_big_lmmsize;
        rc = mo_xattr_get(info->mti_env, mdt_object_child(o),
                          buf, XATTR_NAME_LINK);
        /* ignore errors, MA_PFID won't be set and it is
         * up to the caller to treat this as an error */
        if (rc == -ERANGE || buf->lb_len == 0) {
                rc = mdt_big_xattr_get(info, o, XATTR_NAME_LINK);
                buf->lb_buf = info->mti_big_lmm;
                buf->lb_len = info->mti_big_lmmsize;
        }

        if (rc < 0)
                RETURN(rc);
        if (rc < sizeof(*leh)) {
                CERROR("short LinkEA on "DFID": rc = %d\n",
                       PFID(mdt_object_fid(o)), rc);
                RETURN(-ENODATA);
        }

        leh = (struct link_ea_header *) buf->lb_buf;
        lee = (struct link_ea_entry *)(leh + 1);
        if (leh->leh_magic == __swab32(LINK_EA_MAGIC)) {
                leh->leh_magic = LINK_EA_MAGIC;
                leh->leh_reccount = __swab32(leh->leh_reccount);
                leh->leh_len = __swab64(leh->leh_len);
        }
        if (leh->leh_magic != LINK_EA_MAGIC)
                RETURN(-EINVAL);
        if (leh->leh_reccount == 0)
                RETURN(-ENODATA);

        memcpy(pfid, &lee->lee_parent_fid, sizeof(*pfid));
        fid_be_to_cpu(pfid, pfid);

        RETURN(0);
}

int mdt_attr_get_complex(struct mdt_thread_info *info,
                         struct mdt_object *o, struct md_attr *ma)
{
        const struct lu_env *env = info->mti_env;
        struct md_object    *next = mdt_object_child(o);
        struct lu_buf       *buf = &info->mti_buf;
        u32                  mode = lu_object_attr(&next->mo_lu);
        int                  need = ma->ma_need;
        int                  rc = 0, rc2;
        ENTRY;

        ma->ma_valid = 0;

        if (need & MA_INODE) {
                ma->ma_need = MA_INODE;
                rc = mo_attr_get(env, next, ma);
                if (rc)
                        GOTO(out, rc);
                ma->ma_valid |= MA_INODE;
        }

        if (need & MA_PFID) {
                rc = mdt_attr_get_pfid(info, o, &ma->ma_pfid);
                if (rc == 0)
                        ma->ma_valid |= MA_PFID;
                /* ignore this error, parent fid is not mandatory */
                rc = 0;
        }

        if (need & MA_LOV && (S_ISREG(mode) || S_ISDIR(mode))) {
                rc = mdt_stripe_get(info, o, ma, XATTR_NAME_LOV);
                if (rc)
                        GOTO(out, rc);
        }

        if (need & MA_LMV && S_ISDIR(mode)) {
                rc = mdt_stripe_get(info, o, ma, XATTR_NAME_LMV);
                if (rc != 0)
                        GOTO(out, rc);
        }

        if (need & MA_LMV_DEF && S_ISDIR(mode)) {
                rc = mdt_stripe_get(info, o, ma, XATTR_NAME_DEFAULT_LMV);
                if (rc != 0)
                        GOTO(out, rc);
        }

        if (need & MA_SOM && S_ISREG(mode)) {
                buf->lb_buf = info->mti_xattr_buf;
                buf->lb_len = sizeof(info->mti_xattr_buf);
                CLASSERT(sizeof(struct som_attrs) <=
                         sizeof(info->mti_xattr_buf));
                rc2 = mo_xattr_get(info->mti_env, next, buf, XATTR_NAME_SOM);
                rc2 = lustre_buf2som(info->mti_xattr_buf, rc2, ma->ma_som);
                if (rc2 == 0)
                        ma->ma_valid |= MA_SOM;
                else if (rc2 < 0 && rc2 != -ENODATA)
                        GOTO(out, rc = rc2);
        }

        if (need & MA_HSM && S_ISREG(mode)) {
                buf->lb_buf = info->mti_xattr_buf;
                buf->lb_len = sizeof(info->mti_xattr_buf);
                CLASSERT(sizeof(struct hsm_attrs) <=
                         sizeof(info->mti_xattr_buf));
                rc2 = mo_xattr_get(info->mti_env, next, buf, XATTR_NAME_HSM);
                rc2 = lustre_buf2hsm(info->mti_xattr_buf, rc2, &ma->ma_hsm);
                if (rc2 == 0)
                        ma->ma_valid |= MA_HSM;
                else if (rc2 < 0 && rc2 != -ENODATA)
                        GOTO(out, rc = rc2);
        }

#ifdef CONFIG_FS_POSIX_ACL
        if (need & MA_ACL_DEF && S_ISDIR(mode)) {
                buf->lb_buf = ma->ma_acl;
                buf->lb_len = ma->ma_acl_size;
                rc2 = mo_xattr_get(env, next, buf, XATTR_NAME_ACL_DEFAULT);
                if (rc2 > 0) {
                        ma->ma_acl_size = rc2;
                        ma->ma_valid |= MA_ACL_DEF;
                } else if (rc2 == -ENODATA) {
                        /* no ACLs */
                        ma->ma_acl_size = 0;
                } else
                        GOTO(out, rc = rc2);
        }
#endif
out:
        ma->ma_need = need;
        CDEBUG(D_INODE, "after getattr rc = %d, ma_valid = "LPX64" ma_lmm=%p\n",
               rc, ma->ma_valid, ma->ma_lmm);
        RETURN(rc);
}

static int mdt_getattr_internal(struct mdt_thread_info *info,
                                struct mdt_object *o, int ma_need)
{
        struct md_object        *next = mdt_object_child(o);
        const struct mdt_body   *reqbody = info->mti_body;
        struct ptlrpc_request   *req = mdt_info_req(info);
        struct md_attr          *ma = &info->mti_attr;
        struct lu_attr          *la = &ma->ma_attr;
        struct req_capsule      *pill = info->mti_pill;
        const struct lu_env     *env = info->mti_env;
        struct mdt_body         *repbody;
        struct lu_buf           *buffer = &info->mti_buf;
        int                     rc;
        int                     is_root;
        ENTRY;

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_GETATTR_PACK))
                RETURN(err_serious(-ENOMEM));

        repbody = req_capsule_server_get(pill, &RMF_MDT_BODY);

        ma->ma_valid = 0;

        if (mdt_object_remote(o)) {
                /* This object is located on remote node.*/
                /* Return -EIO for old client */
                if (!mdt_is_dne_client(req->rq_export))
                        GOTO(out, rc = -EIO);

                repbody->fid1 = *mdt_object_fid(o);
                repbody->valid = OBD_MD_FLID | OBD_MD_MDS;
                GOTO(out, rc = 0);
        }

        if (reqbody->eadatasize > 0) {
                buffer->lb_buf = req_capsule_server_get(pill, &RMF_MDT_MD);
                if (buffer->lb_buf == NULL)
                        GOTO(out, rc = -EPROTO);
                buffer->lb_len = req_capsule_get_size(pill, &RMF_MDT_MD,
                                                      RCL_SERVER);
        } else {
                buffer->lb_buf = NULL;
                buffer->lb_len = 0;
                ma_need &= ~(MA_LOV | MA_LMV);
                CDEBUG(D_INFO, "%s: RPC from %s: does not need LOVEA.\n",
                       mdt_obd_name(info->mti_mdt),
                       req->rq_export->exp_client_uuid.uuid);
        }

        /* If it is dir object and client require MEA, then we got MEA */
        if (S_ISDIR(lu_object_attr(&next->mo_lu)) &&
            (reqbody->valid & (OBD_MD_MEA | OBD_MD_DEFAULT_MEA))) {
                /* Assumption: MDT_MD size is enough for lmv size. */
                ma->ma_lmv = buffer->lb_buf;
                ma->ma_lmv_size = buffer->lb_len;
                ma->ma_need = MA_INODE;
                if (ma->ma_lmv_size > 0) {
                        if (reqbody->valid & OBD_MD_MEA)
                                ma->ma_need |= MA_LMV;
                        else if (reqbody->valid & OBD_MD_DEFAULT_MEA)
                                ma->ma_need |= MA_LMV_DEF;
                }
        } else {
                ma->ma_lmm = buffer->lb_buf;
                ma->ma_lmm_size = buffer->lb_len;
                ma->ma_need = MA_INODE | MA_HSM;
                if (ma->ma_lmm_size > 0)
                        ma->ma_need |= MA_LOV;
        }

        if (S_ISDIR(lu_object_attr(&next->mo_lu)) &&
            reqbody->valid & OBD_MD_FLDIREA  &&
            lustre_msg_get_opc(req->rq_reqmsg) == MDS_GETATTR) {
                /* get default stripe info for this dir. */
                ma->ma_need |= MA_LOV_DEF;
        }
        ma->ma_need |= ma_need;
        if (ma->ma_need & MA_SOM)
                ma->ma_som = &info->mti_u.som.data;

        rc = mdt_attr_get_complex(info, o, ma);
        if (unlikely(rc)) {
                CERROR("%s: getattr error for "DFID": rc = %d\n",
                       mdt_obd_name(info->mti_mdt),
                       PFID(mdt_object_fid(o)), rc);
                RETURN(rc);
        }

        /* if file is released, check if a restore is running */
        if ((ma->ma_valid & MA_HSM) && (ma->ma_hsm.mh_flags & HS_RELEASED) &&
            mdt_hsm_restore_is_running(info, mdt_object_fid(o))) {
                repbody->t_state = MS_RESTORE;
                repbody->valid |= OBD_MD_TSTATE;
        }

        is_root = lu_fid_eq(mdt_object_fid(o), &info->mti_mdt->mdt_md_root_fid);

        /* the Lustre protocol supposes to return default striping
         * on the user-visible root if explicitly requested */
        if ((ma->ma_valid & MA_LOV) == 0 && S_ISDIR(la->la_mode) &&
            (ma->ma_need & MA_LOV_DEF && is_root) && ma->ma_need & MA_LOV) {
                struct lu_fid      rootfid;
                struct mdt_object *root;
                struct mdt_device *mdt = info->mti_mdt;

                rc = dt_root_get(env, mdt->mdt_bottom, &rootfid);
                if (rc)
                        RETURN(rc);
                root = mdt_object_find(env, mdt, &rootfid);
                if (IS_ERR(root))
                        RETURN(PTR_ERR(root));
                rc = mdt_stripe_get(info, root, ma, XATTR_NAME_LOV);
                mdt_object_put(info->mti_env, root);
                if (unlikely(rc)) {
                        CERROR("%s: getattr error for "DFID": rc = %d\n",
                               mdt_obd_name(info->mti_mdt),
                               PFID(mdt_object_fid(o)), rc);
                        RETURN(rc);
                }
        }

        if (likely(ma->ma_valid & MA_INODE))
                mdt_pack_attr2body(info, repbody, la, mdt_object_fid(o));
        else
                RETURN(-EFAULT);

        if (mdt_body_has_lov(la, reqbody)) {
                if (ma->ma_valid & MA_LOV) {
                        LASSERT(ma->ma_lmm_size);
                        repbody->eadatasize = ma->ma_lmm_size;
                        if (S_ISDIR(la->la_mode))
                                repbody->valid |= OBD_MD_FLDIREA;
                        else
                                repbody->valid |= OBD_MD_FLEASIZE;
                        mdt_dump_lmm(D_INFO, ma->ma_lmm, repbody->valid);
                }
                if (ma->ma_valid & MA_LMV) {
                        LASSERT(S_ISDIR(la->la_mode));
                        mdt_dump_lmv(D_INFO, ma->ma_lmv);
                        repbody->eadatasize = ma->ma_lmv_size;
                        repbody->valid |= (OBD_MD_FLDIREA|OBD_MD_MEA);
                }
                if (ma->ma_valid & MA_LMV_DEF) {
                        LASSERT(S_ISDIR(la->la_mode));
                        repbody->eadatasize = ma->ma_lmv_size;
                        repbody->valid |= (OBD_MD_FLDIREA|OBD_MD_DEFAULT_MEA);
                }
        } else if (S_ISLNK(la->la_mode) &&
                   reqbody->valid & OBD_MD_LINKNAME) {
                buffer->lb_buf = ma->ma_lmm;
                /* eadatasize from client includes NULL-terminator, so
                 * there is no need to read it */
                buffer->lb_len = reqbody->eadatasize - 1;
                rc = mo_readlink(env, next, buffer);
                if (unlikely(rc <= 0)) {
                        CERROR("%s: readlink failed for "DFID": rc = %d\n",
                               mdt_obd_name(info->mti_mdt),
                               PFID(mdt_object_fid(o)), rc);
                        rc = -EFAULT;
                } else {
                        int print_limit = min_t(int, PAGE_CACHE_SIZE - 128, rc);

                        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_READLINK_EPROTO))
                                rc -= 2;
                        repbody->valid |= OBD_MD_LINKNAME;
                        /* we need to report back size with NULL-terminator
                         * because client expects that */
                        repbody->eadatasize = rc + 1;
                        if (repbody->eadatasize != reqbody->eadatasize)
                                CDEBUG(D_INODE, "%s: Read shorter symlink %d "
                                       "on "DFID ", expected %d\n",
                                       mdt_obd_name(info->mti_mdt),
                                       rc, PFID(mdt_object_fid(o)),
                                       reqbody->eadatasize - 1);
                        /* NULL terminate */
                        ((char *)ma->ma_lmm)[rc] = 0;

                        /* If the total CDEBUG() size is larger than a page, it
                         * will print a warning to the console, avoid this by
                         * printing just the last part of the symlink. */
                        CDEBUG(D_INODE, "symlink dest %s%.*s, len = %d\n",
                               print_limit < rc ? "..." : "", print_limit,
                               (char *)ma->ma_lmm + rc - print_limit, rc);
                        rc = 0;
                }
        }

        if (reqbody->valid & OBD_MD_FLMODEASIZE) {
                repbody->max_cookiesize = 0;
                repbody->max_mdsize = info->mti_mdt->mdt_max_mdsize;
                repbody->valid |= OBD_MD_FLMODEASIZE;
                CDEBUG(D_INODE, "I am going to change the MAX_MD_SIZE & "
                       "MAX_COOKIE to : %d:%d\n", repbody->max_mdsize,
                       repbody->max_cookiesize);
        }

        if (exp_connect_rmtclient(info->mti_exp) &&
            reqbody->valid & OBD_MD_FLRMTPERM) {
                void *buf = req_capsule_server_get(pill, &RMF_ACL);

                /* mdt_getattr_lock only */
                rc = mdt_pack_remote_perm(info, o, buf);
                if (rc) {
                        repbody->valid &= ~OBD_MD_FLRMTPERM;
                        repbody->aclsize = 0;
                        RETURN(rc);
                } else {
                        repbody->valid |= OBD_MD_FLRMTPERM;
                        repbody->aclsize = sizeof(struct mdt_remote_perm);
                }
        }
#ifdef CONFIG_FS_POSIX_ACL
        else if ((exp_connect_flags(req->rq_export) & OBD_CONNECT_ACL) &&
                 (reqbody->valid & OBD_MD_FLACL)) {
                buffer->lb_buf = req_capsule_server_get(pill, &RMF_ACL);
                buffer->lb_len = req_capsule_get_size(pill,
                                                      &RMF_ACL, RCL_SERVER);
                if (buffer->lb_len > 0) {
                        rc = mo_xattr_get(env, next, buffer,
                                          XATTR_NAME_ACL_ACCESS);
                        if (rc < 0) {
                                if (rc == -ENODATA) {
                                        repbody->aclsize = 0;
                                        repbody->valid |= OBD_MD_FLACL;
                                        rc = 0;
                                } else if (rc == -EOPNOTSUPP) {
                                        rc = 0;
                                } else {
                                        CERROR("%s: unable to read "DFID
                                               " ACL: rc = %d\n",
                                               mdt_obd_name(info->mti_mdt),
                                               PFID(mdt_object_fid(o)), rc);
                                }
                        } else {
                                repbody->aclsize = rc;
                                repbody->valid |= OBD_MD_FLACL;
                                rc = 0;
                        }
                }
        }
#endif

        if (reqbody->valid & OBD_MD_FLMDSCAPA &&
            info->mti_mdt->mdt_lut.lut_mds_capa &&
            exp_connect_flags(info->mti_exp) & OBD_CONNECT_MDS_CAPA) {
                struct lustre_capa *capa;

                capa = req_capsule_server_get(pill, &RMF_CAPA1);
                LASSERT(capa);
                capa->lc_opc = CAPA_OPC_MDS_DEFAULT;
                rc = mo_capa_get(env, next, capa, 0);
                if (rc)
                        RETURN(rc);
                repbody->valid |= OBD_MD_FLMDSCAPA;
        }

out:
        if (rc == 0)
                mdt_counter_incr(req, LPROC_MDT_GETATTR);

        RETURN(rc);
}

static int mdt_renew_capa(struct mdt_thread_info *info)
{
        struct mdt_object  *obj = info->mti_object;
        struct mdt_body    *body;
        struct lustre_capa *capa, *c;
        int rc;
        ENTRY;

        /* if object doesn't exist, or server has disabled capability,
         * return directly, client will find body->valid OBD_MD_FLOSSCAPA
         * flag not set.
         */
        if (!obj || !info->mti_mdt->mdt_lut.lut_oss_capa ||
            !(exp_connect_flags(info->mti_exp) & OBD_CONNECT_OSS_CAPA))
                RETURN(0);

        body = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
        LASSERT(body != NULL);

        c = req_capsule_client_get(info->mti_pill, &RMF_CAPA1);
        LASSERT(c);

        capa = req_capsule_server_get(info->mti_pill, &RMF_CAPA2);
        LASSERT(capa);

        *capa = *c;
        rc = mo_capa_get(info->mti_env, mdt_object_child(obj), capa, 1);
        if (rc == 0)
                body->valid |= OBD_MD_FLOSSCAPA;
        RETURN(rc);
}

static int mdt_getattr(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info = tsi2mdt_info(tsi);
        struct mdt_object       *obj = info->mti_object;
        struct req_capsule      *pill = info->mti_pill;
        struct mdt_body         *reqbody;
        struct mdt_body         *repbody;
        int rc, rc2;
        ENTRY;

        reqbody = req_capsule_client_get(pill, &RMF_MDT_BODY);
        LASSERT(reqbody);

        if (reqbody->valid & OBD_MD_FLOSSCAPA) {
                rc = req_capsule_server_pack(pill);
                if (unlikely(rc))
                        RETURN(err_serious(rc));
                rc = mdt_renew_capa(info);
                GOTO(out_shrink, rc);
        }

        LASSERT(obj != NULL);
        LASSERT(lu_object_assert_exists(&obj->mot_obj));

        /* Unlike intent case where we need to pre-fill out buffers early on
         * in intent policy for ldlm reasons, here we can have a much better
         * guess at EA size by just reading it from disk.
         * Exceptions are readdir and (missing) directory striping */
        /* Readlink */
        if (reqbody->valid & OBD_MD_LINKNAME) {
                /* No easy way to know how long is the symlink, but it cannot
                 * be more than PATH_MAX, so we allocate +1 */
                rc = PATH_MAX + 1;

        /* A special case for fs ROOT: getattr there might fetch
         * default EA for entire fs, not just for this dir!
         */
        } else if (lu_fid_eq(mdt_object_fid(obj),
                             &info->mti_mdt->mdt_md_root_fid) &&
                   (reqbody->valid & OBD_MD_FLDIREA) &&
                   (lustre_msg_get_opc(mdt_info_req(info)->rq_reqmsg) ==
                                                                 MDS_GETATTR)) {
                /* Should the default strping be bigger, mdt_fix_reply
                 * will reallocate */
                rc = DEF_REP_MD_SIZE;
        } else {
                /* Read the actual EA size from disk */
                rc = mdt_attr_get_eabuf_size(info, obj);
        }

        if (rc < 0)
                GOTO(out_shrink, rc);

        req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER, rc);

        rc = req_capsule_server_pack(pill);
        if (unlikely(rc != 0))
                GOTO(out, rc = err_serious(rc));

        repbody = req_capsule_server_get(pill, &RMF_MDT_BODY);
        LASSERT(repbody != NULL);
        repbody->eadatasize = 0;
        repbody->aclsize = 0;

        if (reqbody->valid & OBD_MD_FLRMTPERM)
                rc = mdt_init_ucred(info, reqbody);
        else
                rc = mdt_check_ucred(info);
        if (unlikely(rc))
                GOTO(out_shrink, rc);

        info->mti_cross_ref = !!(reqbody->valid & OBD_MD_FLCROSSREF);

        /*
         * Don't check capability at all, because rename might getattr for
         * remote obj, and at that time no capability is available.
         */
        mdt_set_capainfo(info, 1, &reqbody->fid1, BYPASS_CAPA);
        rc = mdt_getattr_internal(info, obj, 0);
        if (reqbody->valid & OBD_MD_FLRMTPERM)
                mdt_exit_ucred(info);
        EXIT;
out_shrink:
        mdt_client_compatibility(info);
        rc2 = mdt_fix_reply(info);
        if (rc == 0)
                rc = rc2;
out:
        mdt_thread_info_fini(info);
        return rc;
}

static int mdt_is_subdir(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info = tsi2mdt_info(tsi);
        struct mdt_object     *o = info->mti_object;
        struct req_capsule    *pill = info->mti_pill;
        const struct mdt_body *body = info->mti_body;
        struct mdt_body       *repbody;
        int                    rc;
        ENTRY;

        LASSERT(o != NULL);

        repbody = req_capsule_server_get(pill, &RMF_MDT_BODY);

        /*
         * We save last checked parent fid to @repbody->fid1 for remote
         * directory case.
         */
        LASSERT(fid_is_sane(&body->fid2));
        LASSERT(mdt_object_exists(o) && !mdt_object_remote(o));
        rc = mdo_is_subdir(info->mti_env, mdt_object_child(o),
                           &body->fid2, &repbody->fid1);
        if (rc == 0 || rc == -EREMOTE)
                repbody->valid |= OBD_MD_FLID;

        mdt_thread_info_fini(info);
        RETURN(rc);
}

static int mdt_swap_layouts(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info;
        struct ptlrpc_request   *req = tgt_ses_req(tsi);
        struct obd_export       *exp = req->rq_export;
        struct mdt_object       *o1, *o2, *o;
        struct mdt_lock_handle  *lh1, *lh2;
        struct mdc_swap_layouts *msl;
        int                      rc;
        ENTRY;

        /* client does not support layout lock, so layout swaping
         * is disabled.
         * FIXME: there is a problem for old clients which don't support
         * layout lock yet. If those clients have already opened the file
         * they won't be notified at all so that old layout may still be
         * used to do IO. This can be fixed after file release is landed by
         * doing exclusive open and taking full EX ibits lock. - Jinshan */
        if (!exp_connect_layout(exp))
                RETURN(-EOPNOTSUPP);

        info = tsi2mdt_info(tsi);

        if (info->mti_dlm_req != NULL)
                ldlm_request_cancel(req, info->mti_dlm_req, 0);

        if (req_capsule_get_size(info->mti_pill, &RMF_CAPA1, RCL_CLIENT))
                mdt_set_capainfo(info, 0, &info->mti_body->fid1,
                                 req_capsule_client_get(info->mti_pill,
                                                        &RMF_CAPA1));

        if (req_capsule_get_size(info->mti_pill, &RMF_CAPA2, RCL_CLIENT))
                mdt_set_capainfo(info, 1, &info->mti_body->fid2,
                                 req_capsule_client_get(info->mti_pill,
                                                        &RMF_CAPA2));

        o1 = info->mti_object;
        o = o2 = mdt_object_find(info->mti_env, info->mti_mdt,
                                &info->mti_body->fid2);
        if (IS_ERR(o))
                GOTO(out, rc = PTR_ERR(o));

        if (mdt_object_remote(o) || !mdt_object_exists(o)) /* remote object */
                GOTO(put, rc = -ENOENT);

        rc = lu_fid_cmp(&info->mti_body->fid1, &info->mti_body->fid2);
        if (unlikely(rc == 0)) /* same file, you kidding me? no-op. */
                GOTO(put, rc);

        if (rc < 0)
                swap(o1, o2);

        /* permission check. Make sure the calling process having permission
         * to write both files. */
        rc = mo_permission(info->mti_env, NULL, mdt_object_child(o1), NULL,
                                MAY_WRITE);
        if (rc < 0)
                GOTO(put, rc);

        rc = mo_permission(info->mti_env, NULL, mdt_object_child(o2), NULL,
                                MAY_WRITE);
        if (rc < 0)
                GOTO(put, rc);

        msl = req_capsule_client_get(info->mti_pill, &RMF_SWAP_LAYOUTS);
        if (msl == NULL)
                GOTO(put, rc = -EPROTO);

        lh1 = &info->mti_lh[MDT_LH_NEW];
        mdt_lock_reg_init(lh1, LCK_EX);
        lh2 = &info->mti_lh[MDT_LH_OLD];
        mdt_lock_reg_init(lh2, LCK_EX);

        rc = mdt_object_lock(info, o1, lh1, MDS_INODELOCK_LAYOUT |
                             MDS_INODELOCK_XATTR, MDT_LOCAL_LOCK);
        if (rc < 0)
                GOTO(put, rc);

        rc = mdt_object_lock(info, o2, lh2, MDS_INODELOCK_LAYOUT |
                             MDS_INODELOCK_XATTR, MDT_LOCAL_LOCK);
        if (rc < 0)
                GOTO(unlock1, rc);

        rc = mo_swap_layouts(info->mti_env, mdt_object_child(o1),
                             mdt_object_child(o2), msl->msl_flags);
        GOTO(unlock2, rc);
unlock2:
        mdt_object_unlock(info, o2, lh2, rc);
unlock1:
        mdt_object_unlock(info, o1, lh1, rc);
put:
        mdt_object_put(info->mti_env, o);
out:
        mdt_thread_info_fini(info);
        RETURN(rc);
}

static int mdt_raw_lookup(struct mdt_thread_info *info,
                          struct mdt_object *parent,
                          const struct lu_name *lname,
                          struct ldlm_reply *ldlm_rep)
{
        struct md_object *next = mdt_object_child(info->mti_object);
        const struct mdt_body *reqbody = info->mti_body;
        struct lu_fid *child_fid = &info->mti_tmp_fid1;
        struct mdt_body *repbody;
        int rc;
        ENTRY;

        if (reqbody->valid != OBD_MD_FLID)
                RETURN(0);

        LASSERT(!info->mti_cross_ref);

        /* Only got the fid of this obj by name */
        fid_zero(child_fid);
        rc = mdo_lookup(info->mti_env, next, lname, child_fid,
                        &info->mti_spec);
#if 0
        /* XXX is raw_lookup possible as intent operation? */
        if (rc != 0) {
                if (rc == -ENOENT)
                        mdt_set_disposition(info, ldlm_rep, DISP_LOOKUP_NEG);
                RETURN(rc);
        } else
                mdt_set_disposition(info, ldlm_rep, DISP_LOOKUP_POS);

        repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
#endif
        if (rc == 0) {
                repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
                repbody->fid1 = *child_fid;
                repbody->valid = OBD_MD_FLID;
        }
        RETURN(1);
}

/*
 * UPDATE lock should be taken against parent, and be release before exit;
 * child_bits lock should be taken against child, and be returned back:
 *            (1)normal request should release the child lock;
 *            (2)intent request will grant the lock to client.
 */
static int mdt_getattr_name_lock(struct mdt_thread_info *info,
                                 struct mdt_lock_handle *lhc,
                                 __u64 child_bits,
                                 struct ldlm_reply *ldlm_rep)
{
        struct ptlrpc_request  *req       = mdt_info_req(info);
        struct mdt_body        *reqbody   = NULL;
        struct mdt_object      *parent    = info->mti_object;
        struct mdt_object      *child;
        struct md_object       *next      = mdt_object_child(parent);
        struct lu_fid          *child_fid = &info->mti_tmp_fid1;
        struct lu_name         *lname     = NULL;
        struct mdt_lock_handle *lhp       = NULL;
        struct ldlm_lock       *lock;
        bool                    is_resent;
        bool                    try_layout;
        int                     ma_need = 0;
        int                     rc;
        ENTRY;

        is_resent = lustre_handle_is_used(&lhc->mlh_reg_lh);
        LASSERT(ergo(is_resent,
                     lustre_msg_get_flags(req->rq_reqmsg) & MSG_RESENT));

        LASSERT(parent != NULL);

        if (info->mti_cross_ref) {
                /* Only getattr on the child. Parent is on another node. */
                mdt_set_disposition(info, ldlm_rep,
                                    DISP_LOOKUP_EXECD | DISP_LOOKUP_POS);
                child = parent;
                CDEBUG(D_INODE, "partial getattr_name child_fid = "DFID", "
                       "ldlm_rep = %p\n",
                       PFID(mdt_object_fid(child)), ldlm_rep);

                if (is_resent) {
                        /* Do not take lock for resent case. */
                        lock = ldlm_handle2lock(&lhc->mlh_reg_lh);
                        LASSERTF(lock != NULL, "Invalid lock handle "LPX64"\n",
                                 lhc->mlh_reg_lh.cookie);
                        LASSERT(fid_res_name_eq(mdt_object_fid(child),
                                                &lock->l_resource->lr_name));
                        LDLM_LOCK_PUT(lock);
                } else {
                        mdt_lock_handle_init(lhc);
                        mdt_lock_reg_init(lhc, LCK_PR);

                        /*
                         * Object's name is on another MDS, no lookup or layout
                         * lock is needed here but update lock is.
                         */
                        child_bits &= ~(MDS_INODELOCK_LOOKUP |
                                        MDS_INODELOCK_LAYOUT);
                        child_bits |= MDS_INODELOCK_PERM | MDS_INODELOCK_UPDATE;

                        rc = mdt_object_lock(info, child, lhc, child_bits,
                                             MDT_LOCAL_LOCK);
                        if (rc < 0)
                                RETURN(rc);
                }

                /* Finally, we can get attr for child. */
                if (!mdt_object_exists(child)) {
                        LU_OBJECT_DEBUG(D_INFO, info->mti_env,
                                        &child->mot_obj,
                                        "remote object doesn't exist.\n");
                        mdt_object_unlock(info, child, lhc, 1);
                        RETURN(-ENOENT);
                }

                mdt_set_capainfo(info, 0, mdt_object_fid(child), BYPASS_CAPA);
                rc = mdt_getattr_internal(info, child, 0);
                if (unlikely(rc != 0))
                        mdt_object_unlock(info, child, lhc, 1);

                RETURN(rc);
        }

        lname = &info->mti_name;
        mdt_name_unpack(info->mti_pill, &RMF_NAME, lname, MNF_FIX_ANON);

        if (lu_name_is_valid(lname)) {
                CDEBUG(D_INODE, "getattr with lock for "DFID"/"DNAME", "
                       "ldlm_rep = %p\n", PFID(mdt_object_fid(parent)),
                       PNAME(lname), ldlm_rep);
        } else {
                reqbody = req_capsule_client_get(info->mti_pill, &RMF_MDT_BODY);
                if (unlikely(reqbody == NULL))
                        RETURN(err_serious(-EPROTO));

                *child_fid = reqbody->fid2;

                if (unlikely(!fid_is_sane(child_fid)))
                        RETURN(err_serious(-EINVAL));

                CDEBUG(D_INODE, "getattr with lock for "DFID"/"DFID", "
                       "ldlm_rep = %p\n",
                       PFID(mdt_object_fid(parent)),
                       PFID(&reqbody->fid2), ldlm_rep);
        }

        mdt_set_disposition(info, ldlm_rep, DISP_LOOKUP_EXECD);

        if (unlikely(!mdt_object_exists(parent)) && lu_name_is_valid(lname)) {
                LU_OBJECT_DEBUG(D_INODE, info->mti_env,
                                &parent->mot_obj,
                                "Parent doesn't exist!\n");
                RETURN(-ESTALE);
        }

        if (mdt_object_remote(parent)) {
                CERROR("%s: parent "DFID" is on remote target\n",
                       mdt_obd_name(info->mti_mdt),
                       PFID(mdt_object_fid(parent)));
                RETURN(-EIO);
        }

        if (lu_name_is_valid(lname)) {
                rc = mdt_raw_lookup(info, parent, lname, ldlm_rep);
                if (rc != 0) {
                        if (rc > 0)
                                rc = 0;
                        RETURN(rc);
                }

                /* step 1: lock parent only if parent is a directory */
                if (S_ISDIR(lu_object_attr(&parent->mot_obj))) {
                        lhp = &info->mti_lh[MDT_LH_PARENT];
                        mdt_lock_pdo_init(lhp, LCK_PR, lname);
                        rc = mdt_object_lock(info, parent, lhp,
                                             MDS_INODELOCK_UPDATE,
                                             MDT_LOCAL_LOCK);
                        if (unlikely(rc != 0))
                                RETURN(rc);
                }

                /* step 2: lookup child's fid by name */
                fid_zero(child_fid);
                rc = mdo_lookup(info->mti_env, next, lname, child_fid,
                                &info->mti_spec);
                if (rc == -ENOENT)
                        mdt_set_disposition(info, ldlm_rep, DISP_LOOKUP_NEG);

                if (rc != 0)
                        GOTO(out_parent, rc);
        }

        mdt_set_disposition(info, ldlm_rep, DISP_LOOKUP_POS);

        /*
         *step 3: find the child object by fid & lock it.
         *        regardless if it is local or remote.
         *
         *Note: LU-3240 (commit 762f2114d282a98ebfa4dbbeea9298a8088ad24e)
         *      set parent dir fid the same as child fid in getattr by fid case
         *      we should not lu_object_find() the object again, could lead
         *      to hung if there is a concurrent unlink destroyed the object.
         */
        if (lu_fid_eq(mdt_object_fid(parent), child_fid)) {
                mdt_object_get(info->mti_env, parent);
                child = parent;
        } else {
                child = mdt_object_find(info->mti_env, info->mti_mdt,
                                        child_fid);
        }

        if (unlikely(IS_ERR(child)))
                GOTO(out_parent, rc = PTR_ERR(child));
        if (is_resent) {
                /* Do not take lock for resent case. */
                lock = ldlm_handle2lock(&lhc->mlh_reg_lh);
                LASSERTF(lock != NULL, "Invalid lock handle "LPX64"\n",
                         lhc->mlh_reg_lh.cookie);

                if (!fid_res_name_eq(mdt_object_fid(child),
                                     &lock->l_resource->lr_name)) {
                        LASSERTF(fid_res_name_eq(mdt_object_fid(parent),
                                                 &lock->l_resource->lr_name),
                                 "Lock res_id: "DLDLMRES", fid: "DFID"\n",
                                 PLDLMRES(lock->l_resource),
                                 PFID(mdt_object_fid(parent)));
                        CWARN("Although resent, but still not get child lock"
                              "parent:"DFID" child:"DFID"\n",
                              PFID(mdt_object_fid(parent)),
                              PFID(mdt_object_fid(child)));
                        lustre_msg_clear_flags(req->rq_reqmsg, MSG_RESENT);
                        LDLM_LOCK_PUT(lock);
                        GOTO(relock, 0);
                }
                LDLM_LOCK_PUT(lock);
        } else {
relock:
                OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RESEND, obd_timeout*2);
                mdt_lock_handle_init(lhc);
                mdt_lock_reg_init(lhc, LCK_PR);
                try_layout = false;

                if (!mdt_object_exists(child)) {
                        LU_OBJECT_DEBUG(D_INODE, info->mti_env,
                                        &child->mot_obj,
                                        "Object doesn't exist!\n");
                        GOTO(out_child, rc = -ENOENT);
                }

                if (!(child_bits & MDS_INODELOCK_UPDATE) &&
                      mdt_object_exists(child) && !mdt_object_remote(child)) {
                        struct md_attr *ma = &info->mti_attr;

                        ma->ma_valid = 0;
                        ma->ma_need = MA_INODE;
                        rc = mdt_attr_get_complex(info, child, ma);
                        if (unlikely(rc != 0))
                                GOTO(out_child, rc);

                        /* If the file has not been changed for some time, we
                         * return not only a LOOKUP lock, but also an UPDATE
                         * lock and this might save us RPC on later STAT. For
                         * directories, it also let negative dentry cache start
                         * working for this dir. */
                        if (ma->ma_valid & MA_INODE &&
                            ma->ma_attr.la_valid & LA_CTIME &&
                            info->mti_mdt->mdt_namespace->ns_ctime_age_limit +
                                ma->ma_attr.la_ctime < cfs_time_current_sec())
                                child_bits |= MDS_INODELOCK_UPDATE;
                }

                /* layout lock must be granted in a best-effort way
                 * for IT operations */
                LASSERT(!(child_bits & MDS_INODELOCK_LAYOUT));
                if (!OBD_FAIL_CHECK(OBD_FAIL_MDS_NO_LL_GETATTR) &&
                    exp_connect_layout(info->mti_exp) &&
                    S_ISREG(lu_object_attr(&child->mot_obj)) &&
                    !mdt_object_remote(child) && ldlm_rep != NULL) {
                        /* try to grant layout lock for regular file. */
                        try_layout = true;
                }

                rc = 0;
                if (try_layout) {
                        child_bits |= MDS_INODELOCK_LAYOUT;
                        /* try layout lock, it may fail to be granted due to
                         * contention at LOOKUP or UPDATE */
                        if (!mdt_object_lock_try(info, child, lhc, child_bits,
                                                 MDT_CROSS_LOCK)) {
                                child_bits &= ~MDS_INODELOCK_LAYOUT;
                                LASSERT(child_bits != 0);
                                rc = mdt_object_lock(info, child, lhc,
                                                child_bits, MDT_CROSS_LOCK);
                        } else {
                                ma_need |= MA_LOV;
                        }
                } else {
                        /* Do not enqueue the UPDATE lock from MDT(cross-MDT),
                         * client will enqueue the lock to the remote MDT */
                        if (mdt_object_remote(child))
                                child_bits &= ~MDS_INODELOCK_UPDATE;
                        rc = mdt_object_lock(info, child, lhc, child_bits,
                                                MDT_CROSS_LOCK);
                }
                if (unlikely(rc != 0))
                        GOTO(out_child, rc);
        }

        lock = ldlm_handle2lock(&lhc->mlh_reg_lh);
        /* Get MA_SOM attributes if update lock is given. */
        if (lock &&
            lock->l_policy_data.l_inodebits.bits & MDS_INODELOCK_UPDATE &&
            S_ISREG(lu_object_attr(&mdt_object_child(child)->mo_lu)))
                ma_need |= MA_SOM;

        /* finally, we can get attr for child. */
        mdt_set_capainfo(info, 1, child_fid, BYPASS_CAPA);
        rc = mdt_getattr_internal(info, child, ma_need);
        if (unlikely(rc != 0)) {
                mdt_object_unlock(info, child, lhc, 1);
        } else if (lock) {
                /* Debugging code. */
                LDLM_DEBUG(lock, "Returning lock to client");
                LASSERTF(fid_res_name_eq(mdt_object_fid(child),
                                         &lock->l_resource->lr_name),
                         "Lock res_id: "DLDLMRES", fid: "DFID"\n",
                         PLDLMRES(lock->l_resource),
                         PFID(mdt_object_fid(child)));
                if (mdt_object_exists(child) && !mdt_object_remote(child))
                        mdt_pack_size2body(info, child);
        }
        if (lock)
                LDLM_LOCK_PUT(lock);

        EXIT;
out_child:
        mdt_object_put(info->mti_env, child);
out_parent:
        if (lhp)
                mdt_object_unlock(info, parent, lhp, 1);
        return rc;
}

/* normal handler: should release the child lock */
static int mdt_getattr_name(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info = tsi2mdt_info(tsi);
        struct mdt_lock_handle *lhc = &info->mti_lh[MDT_LH_CHILD];
        struct mdt_body        *reqbody;
        struct mdt_body        *repbody;
        int rc, rc2;
        ENTRY;

        reqbody = req_capsule_client_get(info->mti_pill, &RMF_MDT_BODY);
        LASSERT(reqbody != NULL);
        repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
        LASSERT(repbody != NULL);

        info->mti_cross_ref = !!(reqbody->valid & OBD_MD_FLCROSSREF);
        repbody->eadatasize = 0;
        repbody->aclsize = 0;

        rc = mdt_init_ucred(info, reqbody);
        if (unlikely(rc))
                GOTO(out_shrink, rc);

        rc = mdt_getattr_name_lock(info, lhc, MDS_INODELOCK_UPDATE, NULL);
        if (lustre_handle_is_used(&lhc->mlh_reg_lh)) {
                ldlm_lock_decref(&lhc->mlh_reg_lh, lhc->mlh_reg_mode);
                lhc->mlh_reg_lh.cookie = 0;
        }
        mdt_exit_ucred(info);
        EXIT;
out_shrink:
        mdt_client_compatibility(info);
        rc2 = mdt_fix_reply(info);
        if (rc == 0)
                rc = rc2;
        mdt_thread_info_fini(info);
        return rc;
}

static int mdt_iocontrol(unsigned int cmd, struct obd_export *exp, int len,
                         void *karg, void *uarg);

static int mdt_set_info(struct tgt_session_info *tsi)
{
        struct ptlrpc_request   *req = tgt_ses_req(tsi);
        char                    *key;
        void                    *val;
        int                      keylen, vallen, rc = 0;

        ENTRY;

        key = req_capsule_client_get(tsi->tsi_pill, &RMF_SETINFO_KEY);
        if (key == NULL) {
                DEBUG_REQ(D_HA, req, "no set_info key");
                RETURN(err_serious(-EFAULT));
        }

        keylen = req_capsule_get_size(tsi->tsi_pill, &RMF_SETINFO_KEY,
                                      RCL_CLIENT);

        val = req_capsule_client_get(tsi->tsi_pill, &RMF_SETINFO_VAL);
        if (val == NULL) {
                DEBUG_REQ(D_HA, req, "no set_info val");
                RETURN(err_serious(-EFAULT));
        }

        vallen = req_capsule_get_size(tsi->tsi_pill, &RMF_SETINFO_VAL,
                                      RCL_CLIENT);

        /* Swab any part of val you need to here */
        if (KEY_IS(KEY_READ_ONLY)) {
                spin_lock(&req->rq_export->exp_lock);
                if (*(__u32 *)val)
                        *exp_connect_flags_ptr(req->rq_export) |=
                                OBD_CONNECT_RDONLY;
                else
                        *exp_connect_flags_ptr(req->rq_export) &=
                                ~OBD_CONNECT_RDONLY;
                spin_unlock(&req->rq_export->exp_lock);
        } else if (KEY_IS(KEY_CHANGELOG_CLEAR)) {
                struct changelog_setinfo *cs = val;

                if (vallen != sizeof(*cs)) {
                        CERROR("%s: bad changelog_clear setinfo size %d\n",
                               tgt_name(tsi->tsi_tgt), vallen);
                        RETURN(-EINVAL);
                }
                if (ptlrpc_req_need_swab(req)) {
                        __swab64s(&cs->cs_recno);
                        __swab32s(&cs->cs_id);
                }

                rc = mdt_iocontrol(OBD_IOC_CHANGELOG_CLEAR, req->rq_export,
                                   vallen, val, NULL);
        } else {
                RETURN(-EINVAL);
        }
        RETURN(rc);
}

static int mdt_readpage(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info = mdt_th_info(tsi->tsi_env);
        struct mdt_object       *object = mdt_obj(tsi->tsi_corpus);
        struct lu_rdpg          *rdpg = &info->mti_u.rdpg.mti_rdpg;
        const struct mdt_body   *reqbody = tsi->tsi_mdt_body;
        struct mdt_body         *repbody;
        int                      rc;
        int                      i;

        ENTRY;

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_READPAGE_PACK))
                RETURN(err_serious(-ENOMEM));

        repbody = req_capsule_server_get(tsi->tsi_pill, &RMF_MDT_BODY);
        if (repbody == NULL || reqbody == NULL)
                RETURN(err_serious(-EFAULT));

        /*
         * prepare @rdpg before calling lower layers and transfer itself. Here
         * reqbody->size contains offset of where to start to read and
         * reqbody->nlink contains number bytes to read.
         */
        rdpg->rp_hash = reqbody->size;
        if (rdpg->rp_hash != reqbody->size) {
                CERROR("Invalid hash: "LPX64" != "LPX64"\n",
                       rdpg->rp_hash, reqbody->size);
                RETURN(-EFAULT);
        }

        rdpg->rp_attrs = reqbody->mode;
        if (exp_connect_flags(tsi->tsi_exp) & OBD_CONNECT_64BITHASH)
                rdpg->rp_attrs |= LUDA_64BITHASH;
        rdpg->rp_count  = min_t(unsigned int, reqbody->nlink,
                                exp_max_brw_size(tsi->tsi_exp));
        rdpg->rp_npages = (rdpg->rp_count + PAGE_CACHE_SIZE - 1) >>
                          PAGE_CACHE_SHIFT;
        OBD_ALLOC(rdpg->rp_pages, rdpg->rp_npages * sizeof rdpg->rp_pages[0]);
        if (rdpg->rp_pages == NULL)
                RETURN(-ENOMEM);

        for (i = 0; i < rdpg->rp_npages; ++i) {
                rdpg->rp_pages[i] = alloc_page(GFP_IOFS);
                if (rdpg->rp_pages[i] == NULL)
                        GOTO(free_rdpg, rc = -ENOMEM);
        }

        /* call lower layers to fill allocated pages with directory data */
        rc = mo_readpage(tsi->tsi_env, mdt_object_child(object), rdpg);
        if (rc < 0)
                GOTO(free_rdpg, rc);

        /* send pages to client */
        rc = tgt_sendpage(tsi, rdpg, rc);

        EXIT;
free_rdpg:

        for (i = 0; i < rdpg->rp_npages; i++)
                if (rdpg->rp_pages[i] != NULL)
                        __free_page(rdpg->rp_pages[i]);
        OBD_FREE(rdpg->rp_pages, rdpg->rp_npages * sizeof rdpg->rp_pages[0]);

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_SENDPAGE))
                RETURN(0);

        return rc;
}

static int mdt_reint_internal(struct mdt_thread_info *info,
                              struct mdt_lock_handle *lhc,
                              __u32 op)
{
        struct req_capsule      *pill = info->mti_pill;
        struct mdt_body         *repbody;
        int                      rc = 0, rc2;

        ENTRY;

        rc = mdt_reint_unpack(info, op);
        if (rc != 0) {
                CERROR("Can't unpack reint, rc %d\n", rc);
                RETURN(err_serious(rc));
        }

        /* for replay (no_create) lmm is not needed, client has it already */
        if (req_capsule_has_field(pill, &RMF_MDT_MD, RCL_SERVER))
                req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER,
                                     DEF_REP_MD_SIZE);

        /* llog cookies are always 0, the field is kept for compatibility */
        if (req_capsule_has_field(pill, &RMF_LOGCOOKIES, RCL_SERVER))
                req_capsule_set_size(pill, &RMF_LOGCOOKIES, RCL_SERVER, 0);

        rc = req_capsule_server_pack(pill);
        if (rc != 0) {
                CERROR("Can't pack response, rc %d\n", rc);
                RETURN(err_serious(rc));
        }

        if (req_capsule_has_field(pill, &RMF_MDT_BODY, RCL_SERVER)) {
                repbody = req_capsule_server_get(pill, &RMF_MDT_BODY);
                LASSERT(repbody);
                repbody->eadatasize = 0;
                repbody->aclsize = 0;
        }

        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_REINT_DELAY, 10);

        /* for replay no cookkie / lmm need, because client have this already */
        if (info->mti_spec.no_create)
                if (req_capsule_has_field(pill, &RMF_MDT_MD, RCL_SERVER))
                        req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER, 0);

        rc = mdt_init_ucred_reint(info);
        if (rc)
                GOTO(out_shrink, rc);

        rc = mdt_fix_attr_ucred(info, op);
        if (rc != 0)
                GOTO(out_ucred, rc = err_serious(rc));

        if (mdt_check_resent(info, mdt_reconstruct, lhc)) {
                DEBUG_REQ(D_INODE, mdt_info_req(info), "resent opt.");
                rc = lustre_msg_get_status(mdt_info_req(info)->rq_repmsg);
                GOTO(out_ucred, rc);
        }
        rc = mdt_reint_rec(info, lhc);
        EXIT;
out_ucred:
        mdt_exit_ucred(info);
out_shrink:
        mdt_client_compatibility(info);
        rc2 = mdt_fix_reply(info);
        if (rc == 0)
                rc = rc2;
        return rc;
}

static long mdt_reint_opcode(struct ptlrpc_request *req,
                             const struct req_format **fmt)
{
        struct mdt_device       *mdt;
        struct mdt_rec_reint    *rec;
        long                     opc;

        rec = req_capsule_client_get(&req->rq_pill, &RMF_REC_REINT);
        if (rec != NULL) {
                opc = rec->rr_opcode;
                DEBUG_REQ(D_INODE, req, "reint opt = %ld", opc);
                if (opc < REINT_MAX && fmt[opc] != NULL)
                        req_capsule_extend(&req->rq_pill, fmt[opc]);
                else {
                        mdt = mdt_exp2dev(req->rq_export);
                        CERROR("%s: Unsupported opcode '%ld' from client '%s':"
                               " rc = %d\n", req->rq_export->exp_obd->obd_name,
                               opc, mdt->mdt_ldlm_client->cli_name, -EFAULT);
                        opc = err_serious(-EFAULT);
                }
        } else {
                opc = err_serious(-EFAULT);
        }
        return opc;
}

static int mdt_reint(struct tgt_session_info *tsi)
{
        long opc;
        int  rc;
        static const struct req_format *reint_fmts[REINT_MAX] = {
                [REINT_SETATTR]  = &RQF_MDS_REINT_SETATTR,
                [REINT_CREATE]   = &RQF_MDS_REINT_CREATE,
                [REINT_LINK]     = &RQF_MDS_REINT_LINK,
                [REINT_UNLINK]   = &RQF_MDS_REINT_UNLINK,
                [REINT_RENAME]   = &RQF_MDS_REINT_RENAME,
                [REINT_OPEN]     = &RQF_MDS_REINT_OPEN,
                [REINT_SETXATTR] = &RQF_MDS_REINT_SETXATTR,
                [REINT_RMENTRY]  = &RQF_MDS_REINT_UNLINK,
                [REINT_MIGRATE]  = &RQF_MDS_REINT_RENAME
        };

        ENTRY;

        opc = mdt_reint_opcode(tgt_ses_req(tsi), reint_fmts);
        if (opc >= 0) {
                struct mdt_thread_info *info = tsi2mdt_info(tsi);
                /*
                 * No lock possible here from client to pass it to reint code
                 * path.
                 */
                rc = mdt_reint_internal(info, NULL, opc);
                mdt_thread_info_fini(info);
        } else {
                rc = opc;
        }

        tsi->tsi_reply_fail_id = OBD_FAIL_MDS_REINT_NET_REP;
        RETURN(rc);
}

/* this should sync the whole device */
static int mdt_device_sync(const struct lu_env *env, struct mdt_device *mdt)
{
        struct dt_device *dt = mdt->mdt_bottom;
        int rc;
        ENTRY;

        rc = dt->dd_ops->dt_sync(env, dt);
        RETURN(rc);
}

/* this should sync this object */
static int mdt_object_sync(struct mdt_thread_info *info)
{
        struct md_object *next;
        int rc;
        ENTRY;

        if (!mdt_object_exists(info->mti_object)) {
                CWARN("Non existing object  "DFID"!\n",
                      PFID(mdt_object_fid(info->mti_object)));
                RETURN(-ESTALE);
        }
        next = mdt_object_child(info->mti_object);
        rc = mo_object_sync(info->mti_env, next);

        RETURN(rc);
}

static int mdt_sync(struct tgt_session_info *tsi)
{
        struct ptlrpc_request   *req = tgt_ses_req(tsi);
        struct req_capsule      *pill = tsi->tsi_pill;
        struct mdt_body         *body;
        int                      rc;

        ENTRY;

        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_SYNC_PACK))
                RETURN(err_serious(-ENOMEM));

        if (fid_seq(&tsi->tsi_mdt_body->fid1) == 0) {
                rc = mdt_device_sync(tsi->tsi_env, mdt_exp2dev(tsi->tsi_exp));
        } else {
                struct mdt_thread_info *info = tsi2mdt_info(tsi);

                /* sync an object */
                rc = mdt_object_sync(info);
                if (rc == 0) {
                        const struct lu_fid *fid;
                        struct lu_attr *la = &info->mti_attr.ma_attr;

                        info->mti_attr.ma_need = MA_INODE;
                        info->mti_attr.ma_valid = 0;
                        rc = mdt_attr_get_complex(info, info->mti_object,
                                                  &info->mti_attr);
                        if (rc == 0) {
                                body = req_capsule_server_get(pill,
                                                              &RMF_MDT_BODY);
                                fid = mdt_object_fid(info->mti_object);
                                mdt_pack_attr2body(info, body, la, fid);
                        }
                }
                mdt_thread_info_fini(info);
        }
        if (rc == 0)
                mdt_counter_incr(req, LPROC_MDT_SYNC);

        RETURN(rc);
}

/*
 * Handle quota control requests to consult current usage/limit, but also
 * to configure quota enforcement
 */
static int mdt_quotactl(struct tgt_session_info *tsi)
{
        struct obd_export       *exp  = tsi->tsi_exp;
        struct req_capsule      *pill = tsi->tsi_pill;
        struct obd_quotactl     *oqctl, *repoqc;
        int                      id, rc;
        struct mdt_device       *mdt = mdt_exp2dev(exp);
        struct lu_device        *qmt = mdt->mdt_qmt_dev;
        ENTRY;

        oqctl = req_capsule_client_get(pill, &RMF_OBD_QUOTACTL);
        if (oqctl == NULL)
                RETURN(err_serious(-EPROTO));

        rc = req_capsule_server_pack(pill);
        if (rc)
                RETURN(err_serious(rc));

        switch (oqctl->qc_cmd) {
        case Q_QUOTACHECK:
        case LUSTRE_Q_INVALIDATE:
        case LUSTRE_Q_FINVALIDATE:
        case Q_QUOTAON:
        case Q_QUOTAOFF:
        case Q_INITQUOTA:
                /* deprecated, not used any more */
                RETURN(-EOPNOTSUPP);
                /* master quotactl */
        case Q_GETINFO:
        case Q_SETINFO:
        case Q_SETQUOTA:
        case Q_GETQUOTA:
                if (qmt == NULL)
                        RETURN(-EOPNOTSUPP);
                /* slave quotactl */
        case Q_GETOINFO:
        case Q_GETOQUOTA:
                break;
        default:
                CERROR("Unsupported quotactl command: %d\n", oqctl->qc_cmd);
                RETURN(-EFAULT);
        }

        /* map uid/gid for remote client */
        id = oqctl->qc_id;
        if (exp_connect_rmtclient(exp)) {
                struct lustre_idmap_table *idmap;

                idmap = exp->exp_mdt_data.med_idmap;

                if (unlikely(oqctl->qc_cmd != Q_GETQUOTA &&
                             oqctl->qc_cmd != Q_GETINFO))
                        RETURN(-EPERM);

                if (oqctl->qc_type == USRQUOTA)
                        id = lustre_idmap_lookup_uid(NULL, idmap, 0,
                                                     oqctl->qc_id);
                else if (oqctl->qc_type == GRPQUOTA)
                        id = lustre_idmap_lookup_gid(NULL, idmap, 0,
                                                     oqctl->qc_id);
                else
                        RETURN(-EINVAL);

                if (id == CFS_IDMAP_NOTFOUND) {
                        CDEBUG(D_QUOTA, "no mapping for id %u\n", oqctl->qc_id);
                        RETURN(-EACCES);
                }
        }

        repoqc = req_capsule_server_get(pill, &RMF_OBD_QUOTACTL);
        if (repoqc == NULL)
                RETURN(err_serious(-EFAULT));

        if (oqctl->qc_id != id)
                swap(oqctl->qc_id, id);

        switch (oqctl->qc_cmd) {

        case Q_GETINFO:
        case Q_SETINFO:
        case Q_SETQUOTA:
        case Q_GETQUOTA:
                /* forward quotactl request to QMT */
                rc = qmt_hdls.qmth_quotactl(tsi->tsi_env, qmt, oqctl);
                break;

        case Q_GETOINFO:
        case Q_GETOQUOTA:
                /* slave quotactl */
                rc = lquotactl_slv(tsi->tsi_env, tsi->tsi_tgt->lut_bottom,
                                   oqctl);
                break;

        default:
                CERROR("Unsupported quotactl command: %d\n", oqctl->qc_cmd);
                RETURN(-EFAULT);
        }

        if (oqctl->qc_id != id)
                swap(oqctl->qc_id, id);

        *repoqc = *oqctl;
        RETURN(rc);
}

/** clone llog ctxt from child (mdd)
 * This allows remote llog (replicator) access.
 * We can either pass all llog RPCs (eg mdt_llog_create) on to child where the
 * context was originally set up, or we can handle them directly.
 * I choose the latter, but that means I need any llog
 * contexts set up by child to be accessable by the mdt.  So we clone the
 * context into our context list here.
 */
static int mdt_llog_ctxt_clone(const struct lu_env *env, struct mdt_device *mdt,
                               int idx)
{
        struct md_device  *next = mdt->mdt_child;
        struct llog_ctxt *ctxt;
        int rc;

        if (!llog_ctxt_null(mdt2obd_dev(mdt), idx))
                return 0;

        rc = next->md_ops->mdo_llog_ctxt_get(env, next, idx, (void **)&ctxt);
        if (rc || ctxt == NULL) {
                return 0;
        }

        rc = llog_group_set_ctxt(&mdt2obd_dev(mdt)->obd_olg, ctxt, idx);
        if (rc)
                CERROR("Can't set mdt ctxt %d\n", rc);

        return rc;
}

static int mdt_llog_ctxt_unclone(const struct lu_env *env,
                                 struct mdt_device *mdt, int idx)
{
        struct llog_ctxt *ctxt;

        ctxt = llog_get_context(mdt2obd_dev(mdt), idx);
        if (ctxt == NULL)
                return 0;
        /* Put once for the get we just did, and once for the clone */
        llog_ctxt_put(ctxt);
        llog_ctxt_put(ctxt);
        return 0;
}

/*
 * sec context handlers
 */
static int mdt_sec_ctx_handle(struct tgt_session_info *tsi)
{
        int rc;

        rc = mdt_handle_idmap(tsi);
        if (unlikely(rc)) {
                struct ptlrpc_request   *req = tgt_ses_req(tsi);
                __u32                    opc;

                opc = lustre_msg_get_opc(req->rq_reqmsg);
                if (opc == SEC_CTX_INIT || opc == SEC_CTX_INIT_CONT)
                        sptlrpc_svc_ctx_invalidate(req);
        }

        CFS_FAIL_TIMEOUT(OBD_FAIL_SEC_CTX_HDL_PAUSE, cfs_fail_val);

        return rc;
}

/*
 * quota request handlers
 */
static int mdt_quota_dqacq(struct tgt_session_info *tsi)
{
        struct mdt_device       *mdt = mdt_exp2dev(tsi->tsi_exp);
        struct lu_device        *qmt = mdt->mdt_qmt_dev;
        int                      rc;
        ENTRY;

        if (qmt == NULL)
                RETURN(err_serious(-EOPNOTSUPP));

        rc = qmt_hdls.qmth_dqacq(tsi->tsi_env, qmt, tgt_ses_req(tsi));
        RETURN(rc);
}

struct mdt_object *mdt_object_new(const struct lu_env *env,
                                  struct mdt_device *d,
                                  const struct lu_fid *f)
{
        struct lu_object_conf conf = { .loc_flags = LOC_F_NEW };
        struct lu_object *o;
        struct mdt_object *m;
        ENTRY;

        CDEBUG(D_INFO, "Allocate object for "DFID"\n", PFID(f));
        o = lu_object_find(env, &d->mdt_lu_dev, f, &conf);
        if (unlikely(IS_ERR(o)))
                m = (struct mdt_object *)o;
        else
                m = mdt_obj(o);
        RETURN(m);
}

struct mdt_object *mdt_object_find(const struct lu_env *env,
                                   struct mdt_device *d,
                                   const struct lu_fid *f)
{
        struct lu_object *o;
        struct mdt_object *m;
        ENTRY;

        CDEBUG(D_INFO, "Find object for "DFID"\n", PFID(f));
        o = lu_object_find(env, &d->mdt_lu_dev, f, NULL);
        if (unlikely(IS_ERR(o)))
                m = (struct mdt_object *)o;
        else
                m = mdt_obj(o);

        RETURN(m);
}

/**
 * Asyncronous commit for mdt device.
 *
 * Pass asynchonous commit call down the MDS stack.
 *
 * \param env environment
 * \param mdt the mdt device
 */
static void mdt_device_commit_async(const struct lu_env *env,
                                    struct mdt_device *mdt)
{
        struct dt_device *dt = mdt->mdt_bottom;
        int rc;

        rc = dt->dd_ops->dt_commit_async(env, dt);
        if (unlikely(rc != 0))
                CWARN("async commit start failed with rc = %d", rc);
}

/**
 * Mark the lock as "synchonous".
 *
 * Mark the lock to deffer transaction commit to the unlock time.
 *
 * \param lock the lock to mark as "synchonous"
 *
 * \see mdt_is_lock_sync
 * \see mdt_save_lock
 */
static inline void mdt_set_lock_sync(struct ldlm_lock *lock)
{
        lock->l_ast_data = (void*)1;
}

/**
 * Check whehter the lock "synchonous" or not.
 *
 * \param lock the lock to check
 * \retval 1 the lock is "synchonous"
 * \retval 0 the lock isn't "synchronous"
 *
 * \see mdt_set_lock_sync
 * \see mdt_save_lock
 */
static inline int mdt_is_lock_sync(struct ldlm_lock *lock)
{
        return lock->l_ast_data != NULL;
}

/**
 * Blocking AST for mdt locks.
 *
 * Starts transaction commit if in case of COS lock conflict or
 * deffers such a commit to the mdt_save_lock.
 *
 * \param lock the lock which blocks a request or cancelling lock
 * \param desc unused
 * \param data unused
 * \param flag indicates whether this cancelling or blocking callback
 * \retval 0
 * \see ldlm_blocking_ast_nocheck
 */
int mdt_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
                     void *data, int flag)
{
        struct obd_device *obd = ldlm_lock_to_ns(lock)->ns_obd;
        struct mdt_device *mdt = mdt_dev(obd->obd_lu_dev);
        int rc;
        ENTRY;

        if (flag == LDLM_CB_CANCELING)
                RETURN(0);
        lock_res_and_lock(lock);
        if (lock->l_blocking_ast != mdt_blocking_ast) {
                unlock_res_and_lock(lock);
                RETURN(0);
        }
        if (mdt_cos_is_enabled(mdt) &&
            lock->l_req_mode & (LCK_PW | LCK_EX) &&
            lock->l_blocking_lock != NULL &&
            lock->l_client_cookie != lock->l_blocking_lock->l_client_cookie) {
                mdt_set_lock_sync(lock);
        }
        rc = ldlm_blocking_ast_nocheck(lock);

        /* There is no lock conflict if l_blocking_lock == NULL,
         * it indicates a blocking ast sent from ldlm_lock_decref_internal
         * when the last reference to a local lock was released */
        if (lock->l_req_mode == LCK_COS && lock->l_blocking_lock != NULL) {
                struct lu_env env;

                rc = lu_env_init(&env, LCT_LOCAL);
                if (unlikely(rc != 0))
                        CWARN("lu_env initialization failed with rc = %d,"
                              "cannot start asynchronous commit\n", rc);
                else
                        mdt_device_commit_async(&env, mdt);
                lu_env_fini(&env);
        }
        RETURN(rc);
}

/* Used for cross-MDT lock */
int mdt_remote_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
                            void *data, int flag)
{
        struct lustre_handle lockh;
        int               rc;

        switch (flag) {
        case LDLM_CB_BLOCKING:
                ldlm_lock2handle(lock, &lockh);
                rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
                if (rc < 0) {
                        CDEBUG(D_INODE, "ldlm_cli_cancel: %d\n", rc);
                        RETURN(rc);
                }
                break;
        case LDLM_CB_CANCELING:
                LDLM_DEBUG(lock, "Revoke remote lock\n");
                break;
        default:
                LBUG();
        }
        RETURN(0);
}

int mdt_remote_object_lock(struct mdt_thread_info *mti,
                           struct mdt_object *o, const struct lu_fid *fid,
                           struct lustre_handle *lh, ldlm_mode_t mode,
                           __u64 ibits)
{
        struct ldlm_enqueue_info *einfo = &mti->mti_einfo;
        ldlm_policy_data_t *policy = &mti->mti_policy;
        struct ldlm_res_id *res_id = &mti->mti_res_id;
        int rc = 0;
        ENTRY;

        LASSERT(mdt_object_remote(o));

        LASSERT(ibits == MDS_INODELOCK_UPDATE);

        fid_build_reg_res_name(fid, res_id);

        memset(einfo, 0, sizeof(*einfo));
        einfo->ei_type = LDLM_IBITS;
        einfo->ei_mode = mode;
        einfo->ei_cb_bl = mdt_remote_blocking_ast;
        einfo->ei_cb_cp = ldlm_completion_ast;
        einfo->ei_enq_slave = 0;
        einfo->ei_res_id = res_id;

        memset(policy, 0, sizeof(*policy));
        policy->l_inodebits.bits = ibits;

        rc = mo_object_lock(mti->mti_env, mdt_object_child(o), lh, einfo,
                            policy);
        RETURN(rc);
}

static int mdt_object_local_lock(struct mdt_thread_info *info,
                                 struct mdt_object *o,
                                 struct mdt_lock_handle *lh, __u64 ibits,
                                 bool nonblock, int locality)
{
        struct ldlm_namespace *ns = info->mti_mdt->mdt_namespace;
        ldlm_policy_data_t *policy = &info->mti_policy;
        struct ldlm_res_id *res_id = &info->mti_res_id;
        __u64 dlmflags;
        int rc;
        ENTRY;

        LASSERT(!lustre_handle_is_used(&lh->mlh_reg_lh));
        LASSERT(!lustre_handle_is_used(&lh->mlh_pdo_lh));
        LASSERT(lh->mlh_reg_mode != LCK_MINMODE);
        LASSERT(lh->mlh_type != MDT_NUL_LOCK);

        /* Only enqueue LOOKUP lock for remote object */
        if (mdt_object_remote(o))
                LASSERT(ibits == MDS_INODELOCK_LOOKUP);

        if (lh->mlh_type == MDT_PDO_LOCK) {
                /* check for exists after object is locked */
                if (mdt_object_exists(o) == 0) {
                        /* Non-existent object shouldn't have PDO lock */
                        RETURN(-ESTALE);
                } else {
                        /* Non-dir object shouldn't have PDO lock */
                        if (!S_ISDIR(lu_object_attr(&o->mot_obj)))
                                RETURN(-ENOTDIR);
                }
        }

        memset(policy, 0, sizeof(*policy));
        fid_build_reg_res_name(mdt_object_fid(o), res_id);

        dlmflags = LDLM_FL_ATOMIC_CB;
        if (nonblock)
                dlmflags |= LDLM_FL_BLOCK_NOWAIT;

        /*
         * Take PDO lock on whole directory and build correct @res_id for lock
         * on part of directory.
         */
        if (lh->mlh_pdo_hash != 0) {
                LASSERT(lh->mlh_type == MDT_PDO_LOCK);
                mdt_lock_pdo_mode(info, o, lh);
                if (lh->mlh_pdo_mode != LCK_NL) {
                        /*
                         * Do not use LDLM_FL_LOCAL_ONLY for parallel lock, it
                         * is never going to be sent to client and we do not
                         * want it slowed down due to possible cancels.
                         */
                        policy->l_inodebits.bits = MDS_INODELOCK_UPDATE;
                        rc = mdt_fid_lock(ns, &lh->mlh_pdo_lh, lh->mlh_pdo_mode,
                                          policy, res_id, dlmflags,
                                          info->mti_exp == NULL ? NULL :
                                          &info->mti_exp->exp_handle.h_cookie);
                        if (unlikely(rc))
                                RETURN(rc);
                }

                /*
                 * Finish res_id initializing by name hash marking part of
                 * directory which is taking modification.
                 */
                res_id->name[LUSTRE_RES_ID_HSH_OFF] = lh->mlh_pdo_hash;
        }

        policy->l_inodebits.bits = ibits;

        /*
         * Use LDLM_FL_LOCAL_ONLY for this lock. We do not know yet if it is
         * going to be sent to client. If it is - mdt_intent_policy() path will
         * fix it up and turn FL_LOCAL flag off.
         */
        rc = mdt_fid_lock(ns, &lh->mlh_reg_lh, lh->mlh_reg_mode, policy,
                          res_id, LDLM_FL_LOCAL_ONLY | dlmflags,
                          info->mti_exp == NULL ? NULL :
                          &info->mti_exp->exp_handle.h_cookie);
        if (rc)
                mdt_object_unlock(info, o, lh, 1);
        else if (unlikely(OBD_FAIL_PRECHECK(OBD_FAIL_MDS_PDO_LOCK)) &&
                 lh->mlh_pdo_hash != 0 &&
                 (lh->mlh_reg_mode == LCK_PW || lh->mlh_reg_mode == LCK_EX)) {
                OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_PDO_LOCK, 15);
        }

        RETURN(rc);
}

static int
mdt_object_lock_internal(struct mdt_thread_info *info, struct mdt_object *o,
                         struct mdt_lock_handle *lh, __u64 ibits,
                         bool nonblock, int locality)
{
        int rc;
        ENTRY;

        if (!mdt_object_remote(o))
                return mdt_object_local_lock(info, o, lh, ibits, nonblock,
                                             locality);

        if (locality == MDT_LOCAL_LOCK) {
                CERROR("%s: try to get local lock for remote object"
                       DFID".\n", mdt_obd_name(info->mti_mdt),
                       PFID(mdt_object_fid(o)));
                RETURN(-EPROTO);
        }

        /* XXX do not support PERM/LAYOUT/XATTR lock for remote object yet */
        ibits &= ~(MDS_INODELOCK_PERM | MDS_INODELOCK_LAYOUT |
                   MDS_INODELOCK_XATTR);
        if (ibits & MDS_INODELOCK_UPDATE) {
                /* Sigh, PDO needs to enqueue 2 locks right now, but
                 * enqueue RPC can only request 1 lock, to avoid extra
                 * RPC, so it will instead enqueue EX lock for remote
                 * object anyway XXX*/
                if (lh->mlh_type == MDT_PDO_LOCK &&
                    lh->mlh_pdo_hash != 0) {
                        CDEBUG(D_INFO, "%s: "DFID" convert PDO lock to"
                               "EX lock.\n", mdt_obd_name(info->mti_mdt),
                               PFID(mdt_object_fid(o)));
                        lh->mlh_pdo_hash = 0;
                        lh->mlh_rreg_mode = LCK_EX;
                        lh->mlh_type = MDT_REG_LOCK;
                }
                rc = mdt_remote_object_lock(info, o, mdt_object_fid(o),
                                            &lh->mlh_rreg_lh,
                                            lh->mlh_rreg_mode,
                                            MDS_INODELOCK_UPDATE);
                if (rc != ELDLM_OK)
                        RETURN(rc);
        }

        /* Only enqueue LOOKUP lock for remote object */
        if (ibits & MDS_INODELOCK_LOOKUP) {
                rc = mdt_object_local_lock(info, o, lh,
                                           MDS_INODELOCK_LOOKUP,
                                           nonblock, locality);
                if (rc != ELDLM_OK)
                        RETURN(rc);
        }

        RETURN(0);
}

int mdt_object_lock(struct mdt_thread_info *info, struct mdt_object *o,
                    struct mdt_lock_handle *lh, __u64 ibits, int locality)
{
        return mdt_object_lock_internal(info, o, lh, ibits, false, locality);
}

int mdt_object_lock_try(struct mdt_thread_info *info, struct mdt_object *o,
                        struct mdt_lock_handle *lh, __u64 ibits, int locality)
{
        struct mdt_lock_handle tmp = *lh;
        int rc;

        rc = mdt_object_lock_internal(info, o, &tmp, ibits, true, locality);
        if (rc == 0)
                *lh = tmp;

        return rc == 0;
}

/**
 * Save a lock within request object.
 *
 * Keep the lock referenced until whether client ACK or transaction
 * commit happens or release the lock immediately depending on input
 * parameters. If COS is ON, a write lock is converted to COS lock
 * before saving.
 *
 * \param info thead info object
 * \param h lock handle
 * \param mode lock mode
 * \param decref force immediate lock releasing
 */
static
void mdt_save_lock(struct mdt_thread_info *info, struct lustre_handle *h,
                   ldlm_mode_t mode, int decref)
{
        ENTRY;

        if (lustre_handle_is_used(h)) {
                if (decref || !info->mti_has_trans ||
                    !(mode & (LCK_PW | LCK_EX))){
                        mdt_fid_unlock(h, mode);
                } else {
                        struct mdt_device *mdt = info->mti_mdt;
                        struct ldlm_lock *lock = ldlm_handle2lock(h);
                        struct ptlrpc_request *req = mdt_info_req(info);
                        int no_ack = 0;

                        LASSERTF(lock != NULL, "no lock for cookie "LPX64"\n",
                                 h->cookie);
                        /* there is no request if mdt_object_unlock() is called
                         * from mdt_export_cleanup()->mdt_add_dirty_flag() */
                        if (likely(req != NULL)) {
                                CDEBUG(D_HA, "request = %p reply state = %p"
                                       " transno = "LPD64"\n", req,
                                       req->rq_reply_state, req->rq_transno);
                                if (mdt_cos_is_enabled(mdt)) {
                                        no_ack = 1;
                                        ldlm_lock_downgrade(lock, LCK_COS);
                                        mode = LCK_COS;
                                }
                                ptlrpc_save_lock(req, h, mode, no_ack);
                        } else {
                                ldlm_lock_decref(h, mode);
                        }
                        if (mdt_is_lock_sync(lock)) {
                                CDEBUG(D_HA, "found sync-lock,"
                                       " async commit started\n");
                                mdt_device_commit_async(info->mti_env,
                                                        mdt);
                        }
                        LDLM_LOCK_PUT(lock);
                }
                h->cookie = 0ull;
        }

        EXIT;
}

/**
 * Unlock mdt object.
 *
 * Immeditely release the regular lock and the PDO lock or save the
 * lock in reqeuest and keep them referenced until client ACK or
 * transaction commit.
 *
 * \param info thread info object
 * \param o mdt object
 * \param lh mdt lock handle referencing regular and PDO locks
 * \param decref force immediate lock releasing
 */
void mdt_object_unlock(struct mdt_thread_info *info, struct mdt_object *o,
                       struct mdt_lock_handle *lh, int decref)
{
        ENTRY;

        mdt_save_lock(info, &lh->mlh_pdo_lh, lh->mlh_pdo_mode, decref);
        mdt_save_lock(info, &lh->mlh_reg_lh, lh->mlh_reg_mode, decref);

        if (lustre_handle_is_used(&lh->mlh_rreg_lh))
                ldlm_lock_decref(&lh->mlh_rreg_lh, lh->mlh_rreg_mode);

        EXIT;
}

struct mdt_object *mdt_object_find_lock(struct mdt_thread_info *info,
                                        const struct lu_fid *f,
                                        struct mdt_lock_handle *lh,
                                        __u64 ibits)
{
        struct mdt_object *o;

        o = mdt_object_find(info->mti_env, info->mti_mdt, f);
        if (!IS_ERR(o)) {
                int rc;

                rc = mdt_object_lock(info, o, lh, ibits,
                                     MDT_LOCAL_LOCK);
                if (rc != 0) {
                        mdt_object_put(info->mti_env, o);
                        o = ERR_PTR(rc);
                }
        }
        return o;
}

void mdt_object_unlock_put(struct mdt_thread_info * info,
                           struct mdt_object * o,
                           struct mdt_lock_handle *lh,
                           int decref)
{
        mdt_object_unlock(info, o, lh, decref);
        mdt_object_put(info->mti_env, o);
}

/*
 * Generic code handling requests that have struct mdt_body passed in:
 *
 *  - extract mdt_body from request and save it in @info, if present;
 *
 *  - create lu_object, corresponding to the fid in mdt_body, and save it in
 *  @info;
 *
 *  - if HABEO_CORPUS flag is set for this request type check whether object
 *  actually exists on storage (lu_object_exists()).
 *
 */
static int mdt_body_unpack(struct mdt_thread_info *info, __u32 flags)
{
        const struct mdt_body    *body;
        struct mdt_object        *obj;
        const struct lu_env      *env;
        struct req_capsule       *pill;
        int                       rc;
        ENTRY;

        env = info->mti_env;
        pill = info->mti_pill;

        body = info->mti_body = req_capsule_client_get(pill, &RMF_MDT_BODY);
        if (body == NULL)
                RETURN(-EFAULT);

        if (!(body->valid & OBD_MD_FLID))
                RETURN(0);

        if (!fid_is_sane(&body->fid1)) {
                CERROR("Invalid fid: "DFID"\n", PFID(&body->fid1));
                RETURN(-EINVAL);
        }

        /*
         * Do not get size or any capa fields before we check that request
         * contains capa actually. There are some requests which do not, for
         * instance MDS_IS_SUBDIR.
         */
        if (req_capsule_has_field(pill, &RMF_CAPA1, RCL_CLIENT) &&
            req_capsule_get_size(pill, &RMF_CAPA1, RCL_CLIENT))
                mdt_set_capainfo(info, 0, &body->fid1,
                                 req_capsule_client_get(pill, &RMF_CAPA1));

        obj = mdt_object_find(env, info->mti_mdt, &body->fid1);
        if (!IS_ERR(obj)) {
                if ((flags & HABEO_CORPUS) &&
                    !mdt_object_exists(obj)) {
                        mdt_object_put(env, obj);
                        /* for capability renew ENOENT will be handled in
                         * mdt_renew_capa */
                        if (body->valid & OBD_MD_FLOSSCAPA)
                                rc = 0;
                        else
                                rc = -ENOENT;
                } else {
                        info->mti_object = obj;
                        rc = 0;
                }
        } else
                rc = PTR_ERR(obj);

        RETURN(rc);
}

static int mdt_unpack_req_pack_rep(struct mdt_thread_info *info, __u32 flags)
{
        struct req_capsule *pill = info->mti_pill;
        int rc;
        ENTRY;

        if (req_capsule_has_field(pill, &RMF_MDT_BODY, RCL_CLIENT))
                rc = mdt_body_unpack(info, flags);
        else
                rc = 0;

        if (rc == 0 && (flags & HABEO_REFERO)) {
                /* Pack reply. */
                if (req_capsule_has_field(pill, &RMF_MDT_MD, RCL_SERVER))
                        req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER,
                                             DEF_REP_MD_SIZE);
                if (req_capsule_has_field(pill, &RMF_LOGCOOKIES, RCL_SERVER))
                        req_capsule_set_size(pill, &RMF_LOGCOOKIES,
                                             RCL_SERVER, 0);

                rc = req_capsule_server_pack(pill);
        }
        RETURN(rc);
}

static int mdt_init_capa_ctxt(const struct lu_env *env, struct mdt_device *m)
{
        struct md_device *next = m->mdt_child;

        return next->md_ops->mdo_init_capa_ctxt(env, next,
                                                m->mdt_lut.lut_mds_capa,
                                                m->mdt_capa_timeout,
                                                m->mdt_capa_alg,
                                                m->mdt_capa_keys);
}

void mdt_lock_handle_init(struct mdt_lock_handle *lh)
{
        lh->mlh_type = MDT_NUL_LOCK;
        lh->mlh_reg_lh.cookie = 0ull;
        lh->mlh_reg_mode = LCK_MINMODE;
        lh->mlh_pdo_lh.cookie = 0ull;
        lh->mlh_pdo_mode = LCK_MINMODE;
        lh->mlh_rreg_lh.cookie = 0ull;
        lh->mlh_rreg_mode = LCK_MINMODE;
}

void mdt_lock_handle_fini(struct mdt_lock_handle *lh)
{
        LASSERT(!lustre_handle_is_used(&lh->mlh_reg_lh));
        LASSERT(!lustre_handle_is_used(&lh->mlh_pdo_lh));
}

/*
 * Initialize fields of struct mdt_thread_info. Other fields are left in
 * uninitialized state, because it's too expensive to zero out whole
 * mdt_thread_info (> 1K) on each request arrival.
 */
void mdt_thread_info_init(struct ptlrpc_request *req,
                          struct mdt_thread_info *info)
{
        int i;

        info->mti_pill = &req->rq_pill;

        /* lock handle */
        for (i = 0; i < ARRAY_SIZE(info->mti_lh); i++)
                mdt_lock_handle_init(&info->mti_lh[i]);

        /* mdt device: it can be NULL while CONNECT */
        if (req->rq_export) {
                info->mti_mdt = mdt_dev(req->rq_export->exp_obd->obd_lu_dev);
                info->mti_exp = req->rq_export;
        } else
                info->mti_mdt = NULL;
        info->mti_env = req->rq_svc_thread->t_env;
        info->mti_transno = lustre_msg_get_transno(req->rq_reqmsg);

        memset(&info->mti_attr, 0, sizeof(info->mti_attr));
        info->mti_big_buf = LU_BUF_NULL;
        info->mti_body = NULL;
        info->mti_object = NULL;
        info->mti_dlm_req = NULL;
        info->mti_has_trans = 0;
        info->mti_cross_ref = 0;
        info->mti_opdata = 0;
        info->mti_big_lmm_used = 0;

        info->mti_spec.no_create = 0;
        info->mti_spec.sp_rm_entry = 0;

        info->mti_spec.u.sp_ea.eadata = NULL;
        info->mti_spec.u.sp_ea.eadatalen = 0;
}

void mdt_thread_info_fini(struct mdt_thread_info *info)
{
        int i;

        if (info->mti_object != NULL) {
                mdt_object_put(info->mti_env, info->mti_object);
                info->mti_object = NULL;
        }

        for (i = 0; i < ARRAY_SIZE(info->mti_lh); i++)
                mdt_lock_handle_fini(&info->mti_lh[i]);
        info->mti_env = NULL;
        info->mti_pill = NULL;
        info->mti_exp = NULL;

        if (unlikely(info->mti_big_buf.lb_buf != NULL))
                lu_buf_free(&info->mti_big_buf);
}

struct mdt_thread_info *tsi2mdt_info(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *mti;
        struct lustre_capa      *lc;

        mti = mdt_th_info(tsi->tsi_env);
        LASSERT(mti != NULL);

        mdt_thread_info_init(tgt_ses_req(tsi), mti);
        if (tsi->tsi_corpus != NULL) {
                struct req_capsule *pill = tsi->tsi_pill;

                mti->mti_object = mdt_obj(tsi->tsi_corpus);
                lu_object_get(tsi->tsi_corpus);

                /*
                 * XXX: must be part of tgt_mdt_body_unpack but moved here
                 * due to mdt_set_capainfo().
                 */
                if (req_capsule_has_field(pill, &RMF_CAPA1, RCL_CLIENT) &&
                    req_capsule_get_size(pill, &RMF_CAPA1, RCL_CLIENT) > 0) {
                        lc = req_capsule_client_get(pill, &RMF_CAPA1);
                        mdt_set_capainfo(mti, 0, &tsi->tsi_mdt_body->fid1, lc);
                }
        }
        mti->mti_body = tsi->tsi_mdt_body;
        mti->mti_dlm_req = tsi->tsi_dlm_req;

        return mti;
}

static int mdt_tgt_connect(struct tgt_session_info *tsi)
{
        struct ptlrpc_request   *req = tgt_ses_req(tsi);
        int                      rc;

        ENTRY;

        rc = tgt_connect(tsi);
        if (rc != 0)
                RETURN(rc);

        rc = mdt_init_idmap(tsi);
        if (rc != 0)
                GOTO(err, rc);
        RETURN(0);
err:
        obd_disconnect(class_export_get(req->rq_export));
        return rc;
}

enum mdt_it_code {
        MDT_IT_OPEN,
        MDT_IT_OCREAT,
        MDT_IT_CREATE,
        MDT_IT_GETATTR,
        MDT_IT_READDIR,
        MDT_IT_LOOKUP,
        MDT_IT_UNLINK,
        MDT_IT_TRUNC,
        MDT_IT_GETXATTR,
        MDT_IT_LAYOUT,
        MDT_IT_QUOTA,
        MDT_IT_NR
};

static int mdt_intent_getattr(enum mdt_it_code opcode,
                              struct mdt_thread_info *info,
                              struct ldlm_lock **,
                              __u64);

static int mdt_intent_getxattr(enum mdt_it_code opcode,
                                struct mdt_thread_info *info,
                                struct ldlm_lock **lockp,
                                __u64 flags);

static int mdt_intent_layout(enum mdt_it_code opcode,
                             struct mdt_thread_info *info,
                             struct ldlm_lock **,
                             __u64);
static int mdt_intent_reint(enum mdt_it_code opcode,
                            struct mdt_thread_info *info,
                            struct ldlm_lock **,
                            __u64);

static struct mdt_it_flavor {
        const struct req_format *it_fmt;
        __u32                    it_flags;
        int                    (*it_act)(enum mdt_it_code ,
                                         struct mdt_thread_info *,
                                         struct ldlm_lock **,
                                         __u64);
        long                     it_reint;
} mdt_it_flavor[] = {
        [MDT_IT_OPEN]     = {
                .it_fmt   = &RQF_LDLM_INTENT,
                /*.it_flags = HABEO_REFERO,*/
                .it_flags = 0,
                .it_act   = mdt_intent_reint,
                .it_reint = REINT_OPEN
        },
        [MDT_IT_OCREAT]   = {
                .it_fmt   = &RQF_LDLM_INTENT,
                /*
                 * OCREAT is not a MUTABOR request as if the file
                 * already exists.
                 * We do the extra check of OBD_CONNECT_RDONLY in
                 * mdt_reint_open() when we really need to create
                 * the object.
                 */
                .it_flags = 0,
                .it_act   = mdt_intent_reint,
                .it_reint = REINT_OPEN
        },
        [MDT_IT_CREATE]   = {
                .it_fmt   = &RQF_LDLM_INTENT,
                .it_flags = MUTABOR,
                .it_act   = mdt_intent_reint,
                .it_reint = REINT_CREATE
        },
        [MDT_IT_GETATTR]  = {
                .it_fmt   = &RQF_LDLM_INTENT_GETATTR,
                .it_flags = HABEO_REFERO,
                .it_act   = mdt_intent_getattr
        },
        [MDT_IT_READDIR]  = {
                .it_fmt   = NULL,
                .it_flags = 0,
                .it_act   = NULL
        },
        [MDT_IT_LOOKUP]   = {
                .it_fmt   = &RQF_LDLM_INTENT_GETATTR,
                .it_flags = HABEO_REFERO,
                .it_act   = mdt_intent_getattr
        },
        [MDT_IT_UNLINK]   = {
                .it_fmt   = &RQF_LDLM_INTENT_UNLINK,
                .it_flags = MUTABOR,
                .it_act   = NULL,
                .it_reint = REINT_UNLINK
        },
        [MDT_IT_TRUNC]    = {
                .it_fmt   = NULL,
                .it_flags = MUTABOR,
                .it_act   = NULL
        },
        [MDT_IT_GETXATTR] = {
                .it_fmt   = &RQF_LDLM_INTENT_GETXATTR,
                .it_flags = HABEO_CORPUS,
                .it_act   = mdt_intent_getxattr
        },
        [MDT_IT_LAYOUT] = {
                .it_fmt   = &RQF_LDLM_INTENT_LAYOUT,
                .it_flags = 0,
                .it_act   = mdt_intent_layout
        }
};

static int
mdt_intent_lock_replace(struct mdt_thread_info *info, struct ldlm_lock **lockp,
                        struct ldlm_lock *new_lock, struct mdt_lock_handle *lh,
                        __u64 flags)
{
        struct ptlrpc_request  *req = mdt_info_req(info);
        struct ldlm_lock       *lock = *lockp;

        /*
         * Get new lock only for cases when possible resent did not find any
         * lock.
         */
        if (new_lock == NULL)
                new_lock = ldlm_handle2lock_long(&lh->mlh_reg_lh, 0);

        if (new_lock == NULL && (flags & LDLM_FL_INTENT_ONLY)) {
                lh->mlh_reg_lh.cookie = 0;
                RETURN(0);
        }

        LASSERTF(new_lock != NULL,
                 "lockh "LPX64"\n", lh->mlh_reg_lh.cookie);

        /*
         * If we've already given this lock to a client once, then we should
         * have no readers or writers.  Otherwise, we should have one reader
         * _or_ writer ref (which will be zeroed below) before returning the
         * lock to a client.
         */
        if (new_lock->l_export == req->rq_export) {
                LASSERT(new_lock->l_readers + new_lock->l_writers == 0);
        } else {
                LASSERT(new_lock->l_export == NULL);
                LASSERT(new_lock->l_readers + new_lock->l_writers == 1);
        }

        *lockp = new_lock;

        if (new_lock->l_export == req->rq_export) {
                /*
                 * Already gave this to the client, which means that we
                 * reconstructed a reply.
                 */
                LASSERT(lustre_msg_get_flags(req->rq_reqmsg) &
                        MSG_RESENT);
                lh->mlh_reg_lh.cookie = 0;
                RETURN(ELDLM_LOCK_REPLACED);
        }

        /*
         * Fixup the lock to be given to the client.
         */
        lock_res_and_lock(new_lock);
        /* Zero new_lock->l_readers and new_lock->l_writers without triggering
         * possible blocking AST. */
        while (new_lock->l_readers > 0) {
                lu_ref_del(&new_lock->l_reference, "reader", new_lock);
                lu_ref_del(&new_lock->l_reference, "user", new_lock);
                new_lock->l_readers--;
        }
        while (new_lock->l_writers > 0) {
                lu_ref_del(&new_lock->l_reference, "writer", new_lock);
                lu_ref_del(&new_lock->l_reference, "user", new_lock);
                new_lock->l_writers--;
        }

        new_lock->l_export = class_export_lock_get(req->rq_export, new_lock);
        new_lock->l_blocking_ast = lock->l_blocking_ast;
        new_lock->l_completion_ast = lock->l_completion_ast;
        new_lock->l_remote_handle = lock->l_remote_handle;
        new_lock->l_flags &= ~LDLM_FL_LOCAL;

        unlock_res_and_lock(new_lock);

        cfs_hash_add(new_lock->l_export->exp_lock_hash,
                     &new_lock->l_remote_handle,
                     &new_lock->l_exp_hash);

        LDLM_LOCK_RELEASE(new_lock);
        lh->mlh_reg_lh.cookie = 0;

        RETURN(ELDLM_LOCK_REPLACED);
}

static void mdt_intent_fixup_resent(struct mdt_thread_info *info,
                                    struct ldlm_lock *new_lock,
                                    struct ldlm_lock **old_lock,
                                    struct mdt_lock_handle *lh,
                                    enum mdt_it_code opcode)
{
        struct ptlrpc_request  *req = mdt_info_req(info);
        struct obd_export      *exp = req->rq_export;
        struct lustre_handle    remote_hdl;
        struct ldlm_request    *dlmreq;
        struct ldlm_lock       *lock;

        if (!(lustre_msg_get_flags(req->rq_reqmsg) & MSG_RESENT))
                return;

        dlmreq = req_capsule_client_get(info->mti_pill, &RMF_DLM_REQ);
        remote_hdl = dlmreq->lock_handle[0];
        /* If the client does not require open lock, it does not need to
         * search lock in exp_lock_hash, since the server thread will
         * make sure the lock will be released, and the resend request
         * can always re-enqueue the lock */
        if ((opcode != MDT_IT_OPEN) || (opcode == MDT_IT_OPEN &&
            info->mti_spec.sp_cr_flags & MDS_OPEN_LOCK)) {
                /* In the function below, .hs_keycmp resolves to
                 * ldlm_export_lock_keycmp() */
                /* coverity[overrun-buffer-val] */
                lock = cfs_hash_lookup(exp->exp_lock_hash, &remote_hdl);
                if (lock) {
                        lock_res_and_lock(lock);
                        if (lock != new_lock) {
                                lh->mlh_reg_lh.cookie = lock->l_handle.h_cookie;
                                lh->mlh_reg_mode = lock->l_granted_mode;

                                LDLM_DEBUG(lock, "Restoring lock cookie");
                                DEBUG_REQ(D_DLMTRACE, req,
                                          "restoring lock cookie "LPX64,
                                          lh->mlh_reg_lh.cookie);
                                if (old_lock)
                                        *old_lock = LDLM_LOCK_GET(lock);
                                cfs_hash_put(exp->exp_lock_hash,
                                             &lock->l_exp_hash);
                                unlock_res_and_lock(lock);
                                return;
                        }
                        cfs_hash_put(exp->exp_lock_hash, &lock->l_exp_hash);
                        unlock_res_and_lock(lock);
                }
        }
        /*
         * If the xid matches, then we know this is a resent request, and allow
         * it. (It's probably an OPEN, for which we don't send a lock.
         */
        if (req_xid_is_last(req))
                return;

        /*
         * This remote handle isn't enqueued, so we never received or processed
         * this request.  Clear MSG_RESENT, because it can be handled like any
         * normal request now.
         */
        lustre_msg_clear_flags(req->rq_reqmsg, MSG_RESENT);

        DEBUG_REQ(D_DLMTRACE, req, "no existing lock with rhandle "LPX64,
                  remote_hdl.cookie);
}

static int mdt_intent_getxattr(enum mdt_it_code opcode,
                                struct mdt_thread_info *info,
                                struct ldlm_lock **lockp,
                                __u64 flags)
{
        struct mdt_lock_handle *lhc = &info->mti_lh[MDT_LH_RMT];
        struct ldlm_reply      *ldlm_rep = NULL;
        int rc, grc;

        /*
         * Initialize lhc->mlh_reg_lh either from a previously granted lock
         * (for the resend case) or a new lock. Below we will use it to
         * replace the original lock.
         */
        mdt_intent_fixup_resent(info, *lockp, NULL, lhc, opcode);
        if (!lustre_handle_is_used(&lhc->mlh_reg_lh)) {
                mdt_lock_reg_init(lhc, (*lockp)->l_req_mode);
                rc = mdt_object_lock(info, info->mti_object, lhc,
                                        MDS_INODELOCK_XATTR,
                                        MDT_LOCAL_LOCK);
                if (rc)
                        return rc;
        }

        grc = mdt_getxattr(info);

        rc = mdt_intent_lock_replace(info, lockp, NULL, lhc, flags);

        if (mdt_info_req(info)->rq_repmsg != NULL)
                ldlm_rep = req_capsule_server_get(info->mti_pill, &RMF_DLM_REP);
        if (ldlm_rep == NULL)
                RETURN(err_serious(-EFAULT));

        ldlm_rep->lock_policy_res2 = grc;

        return rc;
}

static int mdt_intent_getattr(enum mdt_it_code opcode,
                              struct mdt_thread_info *info,
                              struct ldlm_lock **lockp,
                              __u64 flags)
{
        struct mdt_lock_handle *lhc = &info->mti_lh[MDT_LH_RMT];
        struct ldlm_lock       *new_lock = NULL;
        __u64                   child_bits;
        struct ldlm_reply      *ldlm_rep;
        struct mdt_body        *reqbody;
        struct mdt_body        *repbody;
        int                     rc, rc2;
        ENTRY;

        reqbody = req_capsule_client_get(info->mti_pill, &RMF_MDT_BODY);
        LASSERT(reqbody);

        repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
        LASSERT(repbody);

        info->mti_cross_ref = !!(reqbody->valid & OBD_MD_FLCROSSREF);
        repbody->eadatasize = 0;
        repbody->aclsize = 0;

        switch (opcode) {
        case MDT_IT_LOOKUP:
                child_bits = MDS_INODELOCK_LOOKUP | MDS_INODELOCK_PERM;
                break;
        case MDT_IT_GETATTR:
                child_bits = MDS_INODELOCK_LOOKUP | MDS_INODELOCK_UPDATE |
                             MDS_INODELOCK_PERM;
                break;
        default:
                CERROR("Unsupported intent (%d)\n", opcode);
                GOTO(out_shrink, rc = -EINVAL);
        }

        rc = mdt_init_ucred(info, reqbody);
        if (rc)
                GOTO(out_shrink, rc);

        ldlm_rep = req_capsule_server_get(info->mti_pill, &RMF_DLM_REP);
        mdt_set_disposition(info, ldlm_rep, DISP_IT_EXECD);

        /* Get lock from request for possible resent case. */
        mdt_intent_fixup_resent(info, *lockp, &new_lock, lhc, opcode);

        rc = mdt_getattr_name_lock(info, lhc, child_bits, ldlm_rep);
        ldlm_rep->lock_policy_res2 = clear_serious(rc);

        if (mdt_get_disposition(ldlm_rep, DISP_LOOKUP_NEG))
                ldlm_rep->lock_policy_res2 = 0;
        if (!mdt_get_disposition(ldlm_rep, DISP_LOOKUP_POS) ||
            ldlm_rep->lock_policy_res2) {
                lhc->mlh_reg_lh.cookie = 0ull;
                GOTO(out_ucred, rc = ELDLM_LOCK_ABORTED);
        }

        rc = mdt_intent_lock_replace(info, lockp, new_lock, lhc, flags);
        EXIT;
out_ucred:
        mdt_exit_ucred(info);
out_shrink:
        mdt_client_compatibility(info);
        rc2 = mdt_fix_reply(info);
        if (rc == 0)
                rc = rc2;
        return rc;
}

static int mdt_intent_layout(enum mdt_it_code opcode,
                             struct mdt_thread_info *info,
                             struct ldlm_lock **lockp,
                             __u64 flags)
{
        struct layout_intent *layout;
        struct lu_fid *fid;
        struct mdt_object *obj = NULL;
        int rc = 0;
        ENTRY;

        if (opcode != MDT_IT_LAYOUT) {
                CERROR("%s: Unknown intent (%d)\n", mdt_obd_name(info->mti_mdt),
                        opcode);
                RETURN(-EINVAL);
        }

        fid = &info->mti_tmp_fid2;
        fid_extract_from_res_name(fid, &(*lockp)->l_resource->lr_name);

        obj = mdt_object_find(info->mti_env, info->mti_mdt, fid);
        if (IS_ERR(obj))
                RETURN(PTR_ERR(obj));

        if (mdt_object_exists(obj) && !mdt_object_remote(obj)) {
                /* get the length of lsm */
                rc = mdt_attr_get_eabuf_size(info, obj);
                if (rc < 0)
                        RETURN(rc);

                if (rc > info->mti_mdt->mdt_max_mdsize)
                        info->mti_mdt->mdt_max_mdsize = rc;
        }

        mdt_object_put(info->mti_env, obj);

        (*lockp)->l_lvb_type = LVB_T_LAYOUT;
        req_capsule_set_size(info->mti_pill, &RMF_DLM_LVB, RCL_SERVER, rc);
        rc = req_capsule_server_pack(info->mti_pill);
        if (rc != 0)
                RETURN(-EINVAL);

        layout = req_capsule_client_get(info->mti_pill, &RMF_LAYOUT_INTENT);
        LASSERT(layout != NULL);
        if (layout->li_opc == LAYOUT_INTENT_ACCESS)
                /* return to normal ldlm handling */
                RETURN(0);

        CERROR("%s: Unsupported layout intent (%d)\n",
                mdt_obd_name(info->mti_mdt), layout->li_opc);
        RETURN(-EINVAL);
}

static int mdt_intent_reint(enum mdt_it_code opcode,
                            struct mdt_thread_info *info,
                            struct ldlm_lock **lockp,
                            __u64 flags)
{
        struct mdt_lock_handle *lhc = &info->mti_lh[MDT_LH_RMT];
        struct ldlm_reply      *rep = NULL;
        long                    opc;
        int                     rc;

        static const struct req_format *intent_fmts[REINT_MAX] = {
                [REINT_CREATE]  = &RQF_LDLM_INTENT_CREATE,
                [REINT_OPEN]    = &RQF_LDLM_INTENT_OPEN
        };

        ENTRY;

        opc = mdt_reint_opcode(mdt_info_req(info), intent_fmts);
        if (opc < 0)
                RETURN(opc);

        if (mdt_it_flavor[opcode].it_reint != opc) {
                CERROR("Reint code %ld doesn't match intent: %d\n",
                       opc, opcode);
                RETURN(err_serious(-EPROTO));
        }

        /* Get lock from request for possible resent case. */
        mdt_intent_fixup_resent(info, *lockp, NULL, lhc, opcode);

        rc = mdt_reint_internal(info, lhc, opc);

        /* Check whether the reply has been packed successfully. */
        if (mdt_info_req(info)->rq_repmsg != NULL)
                rep = req_capsule_server_get(info->mti_pill, &RMF_DLM_REP);
        if (rep == NULL)
                RETURN(err_serious(-EFAULT));

        /* MDC expects this in any case */
        if (rc != 0)
                mdt_set_disposition(info, rep, DISP_LOOKUP_EXECD);

        /* the open lock or the lock for cross-ref object should be
         * returned to the client */
        if (rc == -EREMOTE || mdt_get_disposition(rep, DISP_OPEN_LOCK)) {
                LASSERT(lustre_handle_is_used(&lhc->mlh_reg_lh));
                rep->lock_policy_res2 = 0;
                rc = mdt_intent_lock_replace(info, lockp, NULL, lhc, flags);
                RETURN(rc);
        }

        rep->lock_policy_res2 = clear_serious(rc);

        if (rep->lock_policy_res2 == -ENOENT &&
            mdt_get_disposition(rep, DISP_LOOKUP_NEG))
                rep->lock_policy_res2 = 0;

        if (rc == -ENOTCONN || rc == -ENODEV ||
            rc == -EOVERFLOW) { /**< if VBR failure then return error */
                /*
                 * If it is the disconnect error (ENODEV & ENOCONN), the error
                 * will be returned by rq_status, and client at ptlrpc layer
                 * will detect this, then disconnect, reconnect the import
                 * immediately, instead of impacting the following the rpc.
                 */
                lhc->mlh_reg_lh.cookie = 0ull;
                RETURN(rc);
        } else {
                /*
                 * For other cases, the error will be returned by intent.
                 * and client will retrieve the result from intent.
                 */
                 /*
                  * FIXME: when open lock is finished, that should be
                  * checked here.
                  */
                if (lustre_handle_is_used(&lhc->mlh_reg_lh)) {
                        LASSERTF(rc == 0, "Error occurred but lock handle "
                                 "is still in use, rc = %d\n", rc);
                        rep->lock_policy_res2 = 0;
                        rc = mdt_intent_lock_replace(info, lockp, NULL, lhc, flags);
                        RETURN(rc);
                } else {
                        lhc->mlh_reg_lh.cookie = 0ull;
                        RETURN(ELDLM_LOCK_ABORTED);
                }
        }
}

static int mdt_intent_code(long itcode)
{
        int rc;

        switch(itcode) {
        case IT_OPEN:
                rc = MDT_IT_OPEN;
                break;
        case IT_OPEN|IT_CREAT:
                rc = MDT_IT_OCREAT;
                break;
        case IT_CREAT:
                rc = MDT_IT_CREATE;
                break;
        case IT_READDIR:
                rc = MDT_IT_READDIR;
                break;
        case IT_GETATTR:
                rc = MDT_IT_GETATTR;
                break;
        case IT_LOOKUP:
                rc = MDT_IT_LOOKUP;
                break;
        case IT_UNLINK:
                rc = MDT_IT_UNLINK;
                break;
        case IT_TRUNC:
                rc = MDT_IT_TRUNC;
                break;
        case IT_GETXATTR:
                rc = MDT_IT_GETXATTR;
                break;
        case IT_LAYOUT:
                rc = MDT_IT_LAYOUT;
                break;
        case IT_QUOTA_DQACQ:
        case IT_QUOTA_CONN:
                rc = MDT_IT_QUOTA;
                break;
        default:
                CERROR("Unknown intent opcode: %ld\n", itcode);
                rc = -EINVAL;
                break;
        }
        return rc;
}

static int mdt_intent_opc(long itopc, struct mdt_thread_info *info,
                          struct ldlm_lock **lockp, __u64 flags)
{
        struct req_capsule   *pill;
        struct mdt_it_flavor *flv;
        int opc;
        int rc;
        ENTRY;

        opc = mdt_intent_code(itopc);
        if (opc < 0)
                RETURN(-EINVAL);

        pill = info->mti_pill;

        if (opc == MDT_IT_QUOTA) {
                struct lu_device *qmt = info->mti_mdt->mdt_qmt_dev;

                if (qmt == NULL)
                        RETURN(-EOPNOTSUPP);

                (*lockp)->l_lvb_type = LVB_T_LQUOTA;
                /* pass the request to quota master */
                rc = qmt_hdls.qmth_intent_policy(info->mti_env, qmt,
                                                 mdt_info_req(info), lockp,
                                                 flags);
                RETURN(rc);
        }

        flv  = &mdt_it_flavor[opc];
        if (flv->it_fmt != NULL)
                req_capsule_extend(pill, flv->it_fmt);

        rc = mdt_unpack_req_pack_rep(info, flv->it_flags);
        if (rc == 0) {
                struct ptlrpc_request *req = mdt_info_req(info);
                if (flv->it_flags & MUTABOR &&
                    exp_connect_flags(req->rq_export) & OBD_CONNECT_RDONLY)
                        RETURN(-EROFS);
        }
        if (rc == 0 && flv->it_act != NULL) {
                struct ldlm_reply *rep;

                /* execute policy */
                rc = flv->it_act(opc, info, lockp, flags);

                /* Check whether the reply has been packed successfully. */
                if (mdt_info_req(info)->rq_repmsg != NULL) {
                        rep = req_capsule_server_get(info->mti_pill,
                                                     &RMF_DLM_REP);
                        rep->lock_policy_res2 =
                                ptlrpc_status_hton(rep->lock_policy_res2);
                }
        } else {
                rc = -EPROTO;
        }
        RETURN(rc);
}

static int mdt_intent_policy(struct ldlm_namespace *ns,
                             struct ldlm_lock **lockp, void *req_cookie,
                             ldlm_mode_t mode, __u64 flags, void *data)
{
        struct tgt_session_info *tsi;
        struct mdt_thread_info  *info;
        struct ptlrpc_request   *req  =  req_cookie;
        struct ldlm_intent      *it;
        struct req_capsule      *pill;
        int rc;

        ENTRY;

        LASSERT(req != NULL);

        tsi = tgt_ses_info(req->rq_svc_thread->t_env);

        info = tsi2mdt_info(tsi);
        LASSERT(info != NULL);
        pill = info->mti_pill;
        LASSERT(pill->rc_req == req);

        if (req->rq_reqmsg->lm_bufcount > DLM_INTENT_IT_OFF) {
                req_capsule_extend(pill, &RQF_LDLM_INTENT_BASIC);
                it = req_capsule_client_get(pill, &RMF_LDLM_INTENT);
                if (it != NULL) {
                        rc = mdt_intent_opc(it->opc, info, lockp, flags);
                        if (rc == 0)
                                rc = ELDLM_OK;

                        /* Lock without inodebits makes no sense and will oops
                         * later in ldlm. Let's check it now to see if we have
                         * ibits corrupted somewhere in mdt_intent_opc().
                         * The case for client miss to set ibits has been
                         * processed by others. */
                        LASSERT(ergo(info->mti_dlm_req->lock_desc.l_resource.\
                                        lr_type == LDLM_IBITS,
                                     info->mti_dlm_req->lock_desc.\
                                        l_policy_data.l_inodebits.bits != 0));
                } else
                        rc = err_serious(-EFAULT);
        } else {
                /* No intent was provided */
                LASSERT(pill->rc_fmt == &RQF_LDLM_ENQUEUE);
                req_capsule_set_size(pill, &RMF_DLM_LVB, RCL_SERVER, 0);
                rc = req_capsule_server_pack(pill);
                if (rc)
                        rc = err_serious(rc);
        }
        mdt_thread_info_fini(info);
        RETURN(rc);
}

static void mdt_deregister_seq_exp(struct mdt_device *mdt)
{
        struct seq_server_site  *ss = mdt_seq_site(mdt);

        if (ss->ss_node_id == 0)
                return;

        if (ss->ss_client_seq != NULL) {
                lustre_deregister_lwp_item(&ss->ss_client_seq->lcs_exp);
                ss->ss_client_seq->lcs_exp = NULL;
        }

        if (ss->ss_server_fld != NULL) {
                lustre_deregister_lwp_item(&ss->ss_server_fld->lsf_control_exp);
                ss->ss_server_fld->lsf_control_exp = NULL;
        }
}

static void mdt_seq_fini_cli(struct mdt_device *mdt)
{
        struct seq_server_site *ss = mdt_seq_site(mdt);

        if (ss == NULL)
                return;

        if (ss->ss_server_seq != NULL)
                seq_server_set_cli(NULL, ss->ss_server_seq, NULL);
}

static int mdt_seq_fini(const struct lu_env *env, struct mdt_device *mdt)
{
        mdt_seq_fini_cli(mdt);
        mdt_deregister_seq_exp(mdt);

        return seq_site_fini(env, mdt_seq_site(mdt));
}

/**
 * It will retrieve its FLDB entries from MDT0, and it only happens
 * when upgrading existent FS to 2.6 or when local FLDB is corrupted,
 * and it needs to refresh FLDB from the MDT0.
 **/
static int mdt_register_lwp_callback(void *data)
{
        struct lu_env           env;
        struct mdt_device       *mdt = data;
        struct lu_server_fld    *fld = mdt_seq_site(mdt)->ss_server_fld;
        int                     rc;
        ENTRY;

        LASSERT(mdt_seq_site(mdt)->ss_node_id != 0);

        if (!likely(fld->lsf_new))
                RETURN(0);

        rc = lu_env_init(&env, LCT_MD_THREAD);
        if (rc) {
                CERROR("%s: cannot init env: rc = %d\n", mdt_obd_name(mdt), rc);
                RETURN(rc);
        }

        rc = fld_update_from_controller(&env, fld);
        if (rc != 0) {
                CERROR("%s: cannot update controller: rc = %d\n",
                       mdt_obd_name(mdt), rc);
                GOTO(out, rc);
        }
out:
        lu_env_fini(&env);
        RETURN(rc);
}

static int mdt_register_seq_exp(struct mdt_device *mdt)
{
        struct seq_server_site  *ss = mdt_seq_site(mdt);
        char                    *lwp_name = NULL;
        int                     rc;

        if (ss->ss_node_id == 0)
                return 0;

        OBD_ALLOC(lwp_name, MAX_OBD_NAME);
        if (lwp_name == NULL)
                GOTO(out_free, rc = -ENOMEM);

        rc = tgt_name2lwp_name(mdt_obd_name(mdt), lwp_name, MAX_OBD_NAME, 0);
        if (rc != 0)
                GOTO(out_free, rc);

        rc = lustre_register_lwp_item(lwp_name, &ss->ss_client_seq->lcs_exp,
                                      NULL, NULL);
        if (rc != 0)
                GOTO(out_free, rc);

        rc = lustre_register_lwp_item(lwp_name,
                                      &ss->ss_server_fld->lsf_control_exp,
                                      mdt_register_lwp_callback, mdt);
        if (rc != 0) {
                lustre_deregister_lwp_item(&ss->ss_client_seq->lcs_exp);
                ss->ss_client_seq->lcs_exp = NULL;
                GOTO(out_free, rc);
        }
out_free:
        if (lwp_name != NULL)
                OBD_FREE(lwp_name, MAX_OBD_NAME);

        return rc;
}

/*
 * Init client sequence manager which is used by local MDS to talk to sequence
 * controller on remote node.
 */
static int mdt_seq_init_cli(const struct lu_env *env, struct mdt_device *mdt)
{
        struct seq_server_site  *ss = mdt_seq_site(mdt);
        int                     rc;
        char                    *prefix;
        ENTRY;

        /* check if this is adding the first MDC and controller is not yet
         * initialized. */
        OBD_ALLOC_PTR(ss->ss_client_seq);
        if (ss->ss_client_seq == NULL)
                RETURN(-ENOMEM);

        OBD_ALLOC(prefix, MAX_OBD_NAME + 5);
        if (prefix == NULL) {
                OBD_FREE_PTR(ss->ss_client_seq);
                ss->ss_client_seq = NULL;
                RETURN(-ENOMEM);
        }

        /* Note: seq_client_fini will be called in seq_site_fini */
        snprintf(prefix, MAX_OBD_NAME + 5, "ctl-%s", mdt_obd_name(mdt));
        rc = seq_client_init(ss->ss_client_seq, NULL, LUSTRE_SEQ_METADATA,
                             prefix, ss->ss_node_id == 0 ?  ss->ss_control_seq :
                                                            NULL);
        OBD_FREE(prefix, MAX_OBD_NAME + 5);
        if (rc != 0) {
                OBD_FREE_PTR(ss->ss_client_seq);
                ss->ss_client_seq = NULL;
                RETURN(rc);
        }

        rc = seq_server_set_cli(env, ss->ss_server_seq, ss->ss_client_seq);

        RETURN(rc);
}

static int mdt_seq_init(const struct lu_env *env, struct mdt_device *mdt)
{
        struct seq_server_site  *ss;
        int                     rc;
        ENTRY;

        ss = mdt_seq_site(mdt);
        /* init sequence controller server(MDT0) */
        if (ss->ss_node_id == 0) {
                OBD_ALLOC_PTR(ss->ss_control_seq);
                if (ss->ss_control_seq == NULL)
                        RETURN(-ENOMEM);

                rc = seq_server_init(env, ss->ss_control_seq, mdt->mdt_bottom,
                                     mdt_obd_name(mdt), LUSTRE_SEQ_CONTROLLER,
                                     ss);
                if (rc)
                        GOTO(out_seq_fini, rc);
        }

        /* Init normal sequence server */
        OBD_ALLOC_PTR(ss->ss_server_seq);
        if (ss->ss_server_seq == NULL)
                GOTO(out_seq_fini, rc = -ENOMEM);

        rc = seq_server_init(env, ss->ss_server_seq, mdt->mdt_bottom,
                             mdt_obd_name(mdt), LUSTRE_SEQ_SERVER, ss);
        if (rc)
                GOTO(out_seq_fini, rc);

        /* init seq client for seq server to talk to seq controller(MDT0) */
        rc = mdt_seq_init_cli(env, mdt);
        if (rc != 0)
                GOTO(out_seq_fini, rc);

        if (ss->ss_node_id != 0)
                /* register controler export through lwp */
                rc = mdt_register_seq_exp(mdt);

        EXIT;
out_seq_fini:
        if (rc)
                mdt_seq_fini(env, mdt);

        return rc;
}

/*
 * FLD wrappers
 */
static int mdt_fld_fini(const struct lu_env *env,
                        struct mdt_device *m)
{
        struct seq_server_site *ss = mdt_seq_site(m);
        ENTRY;

        if (ss && ss->ss_server_fld) {
                fld_server_fini(env, ss->ss_server_fld);
                OBD_FREE_PTR(ss->ss_server_fld);
                ss->ss_server_fld = NULL;
        }

        RETURN(0);
}

static int mdt_fld_init(const struct lu_env *env,
                        const char *uuid,
                        struct mdt_device *m)
{
        struct seq_server_site *ss;
        int rc;
        ENTRY;

        ss = mdt_seq_site(m);

        OBD_ALLOC_PTR(ss->ss_server_fld);
        if (ss->ss_server_fld == NULL)
                RETURN(rc = -ENOMEM);

        rc = fld_server_init(env, ss->ss_server_fld, m->mdt_bottom, uuid,
                             LU_SEQ_RANGE_MDT);
        if (rc) {
                OBD_FREE_PTR(ss->ss_server_fld);
                ss->ss_server_fld = NULL;
                RETURN(rc);
        }

        RETURN(0);
}

static void mdt_stack_pre_fini(const struct lu_env *env,
                           struct mdt_device *m, struct lu_device *top)
{
        struct lustre_cfg_bufs  *bufs;
        struct lustre_cfg       *lcfg;
        struct mdt_thread_info  *info;
        ENTRY;

        LASSERT(top);

        info = lu_context_key_get(&env->le_ctx, &mdt_thread_key);
        LASSERT(info != NULL);

        bufs = &info->mti_u.bufs;

        LASSERT(m->mdt_child_exp);
        LASSERT(m->mdt_child_exp->exp_obd);

        /* process cleanup, pass mdt obd name to get obd umount flags */
        /* XXX: this is needed because all layers are referenced by
         * objects (some of them are pinned by osd, for example *
         * the proper solution should be a model where object used
         * by osd only doesn't have mdt/mdd slices -bzzz */
        lustre_cfg_bufs_reset(bufs, mdt_obd_name(m));
        lustre_cfg_bufs_set_string(bufs, 1, NULL);
        lcfg = lustre_cfg_new(LCFG_PRE_CLEANUP, bufs);
        if (!lcfg) {
                CERROR("%s:Cannot alloc lcfg!\n", mdt_obd_name(m));
                return;
        }
        top->ld_ops->ldo_process_config(env, top, lcfg);
        lustre_cfg_free(lcfg);
        EXIT;
}

static void mdt_stack_fini(const struct lu_env *env,
                           struct mdt_device *m, struct lu_device *top)
{
        struct obd_device       *obd = mdt2obd_dev(m);
        struct lustre_cfg_bufs  *bufs;
        struct lustre_cfg       *lcfg;
        struct mdt_thread_info  *info;
        char                     flags[3] = "";
        ENTRY;

        info = lu_context_key_get(&env->le_ctx, &mdt_thread_key);
        LASSERT(info != NULL);

        lu_dev_del_linkage(top->ld_site, top);

        lu_site_purge(env, top->ld_site, -1);

        bufs = &info->mti_u.bufs;
        /* process cleanup, pass mdt obd name to get obd umount flags */
        /* another purpose is to let all layers to release their objects */
        lustre_cfg_bufs_reset(bufs, mdt_obd_name(m));
        if (obd->obd_force)
                strcat(flags, "F");
        if (obd->obd_fail)
                strcat(flags, "A");
        lustre_cfg_bufs_set_string(bufs, 1, flags);
        lcfg = lustre_cfg_new(LCFG_CLEANUP, bufs);
        if (!lcfg) {
                CERROR("Cannot alloc lcfg!\n");
                return;
        }
        LASSERT(top);
        top->ld_ops->ldo_process_config(env, top, lcfg);
        lustre_cfg_free(lcfg);

        lu_site_purge(env, top->ld_site, -1);

        m->mdt_child = NULL;
        m->mdt_bottom = NULL;

        obd_disconnect(m->mdt_child_exp);
        m->mdt_child_exp = NULL;

        obd_disconnect(m->mdt_bottom_exp);
        m->mdt_child_exp = NULL;
}

static int mdt_connect_to_next(const struct lu_env *env, struct mdt_device *m,
                               const char *next, struct obd_export **exp)
{
        struct obd_connect_data *data = NULL;
        struct obd_device       *obd;
        int                      rc;
        ENTRY;

        OBD_ALLOC_PTR(data);
        if (data == NULL)
                GOTO(out, rc = -ENOMEM);

        obd = class_name2obd(next);
        if (obd == NULL) {
                CERROR("%s: can't locate next device: %s\n",
                       mdt_obd_name(m), next);
                GOTO(out, rc = -ENOTCONN);
        }

        data->ocd_connect_flags = OBD_CONNECT_VERSION;
        data->ocd_version = LUSTRE_VERSION_CODE;

        rc = obd_connect(NULL, exp, obd, &obd->obd_uuid, data, NULL);
        if (rc) {
                CERROR("%s: cannot connect to next dev %s (%d)\n",
                       mdt_obd_name(m), next, rc);
                GOTO(out, rc);
        }

out:
        if (data)
                OBD_FREE_PTR(data);
        RETURN(rc);
}

static int mdt_stack_init(const struct lu_env *env, struct mdt_device *mdt,
                          struct lustre_cfg *cfg)
{
        char                   *dev = lustre_cfg_string(cfg, 0);
        int                     rc, name_size, uuid_size;
        char                   *name, *uuid, *p;
        struct lustre_cfg_bufs *bufs;
        struct lustre_cfg      *lcfg;
        struct obd_device      *obd;
        struct lustre_profile  *lprof;
        struct lu_site         *site;
        ENTRY;

        /* in 1.8 we had the only device in the stack - MDS.
         * 2.0 introduces MDT, MDD, OSD; MDT starts others internally.
         * in 2.3 OSD is instantiated by obd_mount.c, so we need
         * to generate names and setup MDT, MDD. MDT will be using
         * generated name to connect to MDD. for MDD the next device
         * will be LOD with name taken from so called "profile" which
         * is generated by mount_option line
         *
         * 1.8 MGS generates config. commands like this:
         *   #06 (104)mount_option 0:  1:lustre-MDT0000  2:lustre-mdtlov
         *   #08 (120)setup   0:lustre-MDT0000  1:dev 2:type 3:lustre-MDT0000
         * 2.0 MGS generates config. commands like this:
         *   #07 (112)mount_option 0:  1:lustre-MDT0000  2:lustre-MDT0000-mdtlov
         *   #08 (160)setup   0:lustre-MDT0000  1:lustre-MDT0000_UUID  2:0
         *                    3:lustre-MDT0000-mdtlov  4:f
         *
         * we generate MDD name from MDT one, just replacing T with D
         *
         * after all the preparations, the logical equivalent will be
         *   #01 (160)setup   0:lustre-MDD0000  1:lustre-MDD0000_UUID  2:0
         *                    3:lustre-MDT0000-mdtlov  4:f
         *   #02 (160)setup   0:lustre-MDT0000  1:lustre-MDT0000_UUID  2:0
         *                    3:lustre-MDD0000  4:f
         *
         *  notice we build the stack from down to top: MDD first, then MDT */

        name_size = MAX_OBD_NAME;
        uuid_size = MAX_OBD_NAME;

        OBD_ALLOC(name, name_size);
        OBD_ALLOC(uuid, uuid_size);
        if (name == NULL || uuid == NULL)
                GOTO(cleanup_mem, rc = -ENOMEM);

        OBD_ALLOC_PTR(bufs);
        if (!bufs)
                GOTO(cleanup_mem, rc = -ENOMEM);

        strcpy(name, dev);
        p = strstr(name, "-MDT");
        if (p == NULL)
                GOTO(free_bufs, rc = -ENOMEM);
        p[3] = 'D';

        snprintf(uuid, MAX_OBD_NAME, "%s_UUID", name);

        lprof = class_get_profile(lustre_cfg_string(cfg, 0));
        if (lprof == NULL || lprof->lp_dt == NULL) {
                CERROR("can't find the profile: %s\n",
                       lustre_cfg_string(cfg, 0));
                GOTO(free_bufs, rc = -EINVAL);
        }

        lustre_cfg_bufs_reset(bufs, name);
        lustre_cfg_bufs_set_string(bufs, 1, LUSTRE_MDD_NAME);
        lustre_cfg_bufs_set_string(bufs, 2, uuid);
        lustre_cfg_bufs_set_string(bufs, 3, lprof->lp_dt);

        lcfg = lustre_cfg_new(LCFG_ATTACH, bufs);
        if (!lcfg)
                GOTO(free_bufs, rc = -ENOMEM);

        rc = class_attach(lcfg);
        if (rc)
                GOTO(lcfg_cleanup, rc);

        obd = class_name2obd(name);
        if (!obd) {
                CERROR("Can not find obd %s (%s in config)\n",
                       MDD_OBD_NAME, lustre_cfg_string(cfg, 0));
                GOTO(class_detach, rc = -EINVAL);
        }

        lustre_cfg_free(lcfg);

        lustre_cfg_bufs_reset(bufs, name);
        lustre_cfg_bufs_set_string(bufs, 1, uuid);
        lustre_cfg_bufs_set_string(bufs, 2, dev);
        lustre_cfg_bufs_set_string(bufs, 3, lprof->lp_dt);

        lcfg = lustre_cfg_new(LCFG_SETUP, bufs);

        rc = class_setup(obd, lcfg);
        if (rc)
                GOTO(class_detach, rc);

        /* connect to MDD we just setup */
        rc = mdt_connect_to_next(env, mdt, name, &mdt->mdt_child_exp);
        if (rc)
                GOTO(class_detach, rc);

        site = mdt->mdt_child_exp->exp_obd->obd_lu_dev->ld_site;
        LASSERT(site);
        LASSERT(mdt_lu_site(mdt) == NULL);
        mdt->mdt_lu_dev.ld_site = site;
        site->ls_top_dev = &mdt->mdt_lu_dev;
        mdt->mdt_child = lu2md_dev(mdt->mdt_child_exp->exp_obd->obd_lu_dev);

        /* now connect to bottom OSD */
        snprintf(name, MAX_OBD_NAME, "%s-osd", dev);
        rc = mdt_connect_to_next(env, mdt, name, &mdt->mdt_bottom_exp);
        if (rc)
                GOTO(class_detach, rc);
        mdt->mdt_bottom =
                lu2dt_dev(mdt->mdt_bottom_exp->exp_obd->obd_lu_dev);

        rc = lu_env_refill((struct lu_env *)env);
        if (rc != 0)
                CERROR("Failure to refill session: '%d'\n", rc);

        lu_dev_add_linkage(site, &mdt->mdt_lu_dev);

        EXIT;
class_detach:
        if (rc)
                class_detach(obd, lcfg);
lcfg_cleanup:
        lustre_cfg_free(lcfg);
free_bufs:
        OBD_FREE_PTR(bufs);
cleanup_mem:
        if (name)
                OBD_FREE(name, name_size);
        if (uuid)
                OBD_FREE(uuid, uuid_size);
        RETURN(rc);
}

/* setup quota master target on MDT0 */
static int mdt_quota_init(const struct lu_env *env, struct mdt_device *mdt,
                          struct lustre_cfg *cfg)
{
        struct obd_device       *obd;
        char                    *dev = lustre_cfg_string(cfg, 0);
        char                    *qmtname, *uuid, *p;
        struct lustre_cfg_bufs  *bufs;
        struct lustre_cfg       *lcfg;
        struct lustre_profile   *lprof;
        struct obd_connect_data *data;
        int                      rc;
        ENTRY;

        LASSERT(mdt->mdt_qmt_exp == NULL);
        LASSERT(mdt->mdt_qmt_dev == NULL);

        /* quota master is on MDT0 only for now */
        if (mdt->mdt_seq_site.ss_node_id != 0)
                RETURN(0);

        /* MGS generates config commands which look as follows:
         *   #01 (160)setup   0:lustre-MDT0000  1:lustre-MDT0000_UUID  2:0
         *                    3:lustre-MDT0000-mdtlov  4:f
         *
         * We generate the QMT name from the MDT one, just replacing MD with QM
         * after all the preparations, the logical equivalent will be:
         *   #01 (160)setup   0:lustre-QMT0000  1:lustre-QMT0000_UUID  2:0
         *                    3:lustre-MDT0000-osd  4:f */
        OBD_ALLOC(qmtname, MAX_OBD_NAME);
        OBD_ALLOC(uuid, UUID_MAX);
        OBD_ALLOC_PTR(bufs);
        OBD_ALLOC_PTR(data);
        if (qmtname == NULL || uuid == NULL || bufs == NULL || data == NULL)
                GOTO(cleanup_mem, rc = -ENOMEM);

        strcpy(qmtname, dev);
        p = strstr(qmtname, "-MDT");
        if (p == NULL)
                GOTO(cleanup_mem, rc = -ENOMEM);
        /* replace MD with QM */
        p[1] = 'Q';
        p[2] = 'M';

        snprintf(uuid, UUID_MAX, "%s_UUID", qmtname);

        lprof = class_get_profile(lustre_cfg_string(cfg, 0));
        if (lprof == NULL || lprof->lp_dt == NULL) {
                CERROR("can't find profile for %s\n",
                       lustre_cfg_string(cfg, 0));
                GOTO(cleanup_mem, rc = -EINVAL);
        }

        lustre_cfg_bufs_reset(bufs, qmtname);
        lustre_cfg_bufs_set_string(bufs, 1, LUSTRE_QMT_NAME);
        lustre_cfg_bufs_set_string(bufs, 2, uuid);
        lustre_cfg_bufs_set_string(bufs, 3, lprof->lp_dt);

        lcfg = lustre_cfg_new(LCFG_ATTACH, bufs);
        if (!lcfg)
                GOTO(cleanup_mem, rc = -ENOMEM);

        rc = class_attach(lcfg);
        if (rc)
                GOTO(lcfg_cleanup, rc);

        obd = class_name2obd(qmtname);
        if (!obd) {
                CERROR("Can not find obd %s (%s in config)\n", qmtname,
                       lustre_cfg_string(cfg, 0));
                GOTO(class_detach, rc = -EINVAL);
        }

        lustre_cfg_free(lcfg);

        lustre_cfg_bufs_reset(bufs, qmtname);
        lustre_cfg_bufs_set_string(bufs, 1, uuid);
        lustre_cfg_bufs_set_string(bufs, 2, dev);

        /* for quota, the next device should be the OSD device */
        lustre_cfg_bufs_set_string(bufs, 3,
                                   mdt->mdt_bottom->dd_lu_dev.ld_obd->obd_name);

        lcfg = lustre_cfg_new(LCFG_SETUP, bufs);

        rc = class_setup(obd, lcfg);
        if (rc)
                GOTO(class_detach, rc);

        mdt->mdt_qmt_dev = obd->obd_lu_dev;

        /* configure local quota objects */
        rc = mdt->mdt_qmt_dev->ld_ops->ldo_prepare(env,
                                                   &mdt->mdt_lu_dev,
                                                   mdt->mdt_qmt_dev);
        if (rc)
                GOTO(class_cleanup, rc);

        /* connect to quota master target */
        data->ocd_connect_flags = OBD_CONNECT_VERSION;
        data->ocd_version = LUSTRE_VERSION_CODE;
        rc = obd_connect(NULL, &mdt->mdt_qmt_exp, obd, &obd->obd_uuid,
                         data, NULL);
        if (rc) {
                CERROR("cannot connect to quota master device %s (%d)\n",
                       qmtname, rc);
                GOTO(class_cleanup, rc);
        }

        EXIT;
class_cleanup:
        if (rc) {
                class_manual_cleanup(obd);
                mdt->mdt_qmt_dev = NULL;
        }
class_detach:
        if (rc)
                class_detach(obd, lcfg);
lcfg_cleanup:
        lustre_cfg_free(lcfg);
cleanup_mem:
        if (bufs)
                OBD_FREE_PTR(bufs);
        if (qmtname)
                OBD_FREE(qmtname, MAX_OBD_NAME);
        if (uuid)
                OBD_FREE(uuid, UUID_MAX);
        if (data)
                OBD_FREE_PTR(data);
        return rc;
}

/* Shutdown quota master target associated with mdt */
static void mdt_quota_fini(const struct lu_env *env, struct mdt_device *mdt)
{
        ENTRY;

        if (mdt->mdt_qmt_exp == NULL)
                RETURN_EXIT;
        LASSERT(mdt->mdt_qmt_dev != NULL);

        /* the qmt automatically shuts down when the mdt disconnects */
        obd_disconnect(mdt->mdt_qmt_exp);
        mdt->mdt_qmt_exp = NULL;
        mdt->mdt_qmt_dev = NULL;
        EXIT;
}

/* mdt_getxattr() is used from mdt_intent_getxattr(), use this wrapper
 * for now. This will be removed along with converting rest of MDT code
 * to use tgt_session_info */
int mdt_tgt_getxattr(struct tgt_session_info *tsi)
{
        struct mdt_thread_info  *info = tsi2mdt_info(tsi);
        int                      rc;

        rc = mdt_getxattr(info);

        mdt_thread_info_fini(info);
        return rc;
}

static struct tgt_handler mdt_tgt_handlers[] = {
TGT_RPC_HANDLER(MDS_FIRST_OPC,
                0,                      MDS_CONNECT,    mdt_tgt_connect,
                &RQF_CONNECT, LUSTRE_OBD_VERSION),
TGT_RPC_HANDLER(MDS_FIRST_OPC,
                0,                      MDS_DISCONNECT, tgt_disconnect,
                &RQF_MDS_DISCONNECT, LUSTRE_OBD_VERSION),
TGT_RPC_HANDLER(MDS_FIRST_OPC,
                HABEO_REFERO,           MDS_SET_INFO,   mdt_set_info,
                &RQF_OBD_SET_INFO, LUSTRE_MDS_VERSION),
TGT_MDT_HDL(0,                          MDS_GET_INFO,   mdt_get_info),
TGT_MDT_HDL(0           | HABEO_REFERO, MDS_GETSTATUS,  mdt_getstatus),
TGT_MDT_HDL(HABEO_CORPUS,               MDS_GETATTR,    mdt_getattr),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_GETATTR_NAME,
                                                        mdt_getattr_name),
TGT_MDT_HDL(HABEO_CORPUS,               MDS_GETXATTR,   mdt_tgt_getxattr),
TGT_MDT_HDL(0           | HABEO_REFERO, MDS_STATFS,     mdt_statfs),
TGT_MDT_HDL(0           | MUTABOR,      MDS_REINT,      mdt_reint),
TGT_MDT_HDL(HABEO_CORPUS,               MDS_CLOSE,      mdt_close),
TGT_MDT_HDL(HABEO_CORPUS,               MDS_DONE_WRITING,
                                                        mdt_done_writing),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_READPAGE,   mdt_readpage),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_SYNC,       mdt_sync),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_IS_SUBDIR,  mdt_is_subdir),
TGT_MDT_HDL(0,                          MDS_QUOTACTL,   mdt_quotactl),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO | MUTABOR, MDS_HSM_PROGRESS,
                                                        mdt_hsm_progress),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO | MUTABOR, MDS_HSM_CT_REGISTER,
                                                        mdt_hsm_ct_register),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO | MUTABOR, MDS_HSM_CT_UNREGISTER,
                                                        mdt_hsm_ct_unregister),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_HSM_STATE_GET,
                                                        mdt_hsm_state_get),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO | MUTABOR, MDS_HSM_STATE_SET,
                                                        mdt_hsm_state_set),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_HSM_ACTION, mdt_hsm_action),
TGT_MDT_HDL(HABEO_CORPUS| HABEO_REFERO, MDS_HSM_REQUEST,
                                                        mdt_hsm_request),
TGT_MDT_HDL(HABEO_CLAVIS | HABEO_CORPUS | HABEO_REFERO | MUTABOR,
            MDS_SWAP_LAYOUTS,
            mdt_swap_layouts),
};

static struct tgt_handler mdt_sec_ctx_ops[] = {
TGT_SEC_HDL_VAR(0,                      SEC_CTX_INIT,     mdt_sec_ctx_handle),
TGT_SEC_HDL_VAR(0,                      SEC_CTX_INIT_CONT,mdt_sec_ctx_handle),
TGT_SEC_HDL_VAR(0,                      SEC_CTX_FINI,     mdt_sec_ctx_handle)
};

static struct tgt_handler mdt_quota_ops[] = {
TGT_QUOTA_HDL(HABEO_REFERO,             QUOTA_DQACQ,      mdt_quota_dqacq),
};

static struct tgt_opc_slice mdt_common_slice[] = {
        {
                .tos_opc_start  = MDS_FIRST_OPC,
                .tos_opc_end    = MDS_LAST_OPC,
                .tos_hs         = mdt_tgt_handlers
        },
        {
                .tos_opc_start  = OBD_FIRST_OPC,
                .tos_opc_end    = OBD_LAST_OPC,
                .tos_hs         = tgt_obd_handlers
        },
        {
                .tos_opc_start  = LDLM_FIRST_OPC,
                .tos_opc_end    = LDLM_LAST_OPC,
                .tos_hs         = tgt_dlm_handlers
        },
        {
                .tos_opc_start  = SEC_FIRST_OPC,
                .tos_opc_end    = SEC_LAST_OPC,
                .tos_hs         = mdt_sec_ctx_ops
        },
        {
                .tos_opc_start  = OUT_UPDATE_FIRST_OPC,
                .tos_opc_end    = OUT_UPDATE_LAST_OPC,
                .tos_hs         = tgt_out_handlers
        },
        {
                .tos_opc_start  = FLD_FIRST_OPC,
                .tos_opc_end    = FLD_LAST_OPC,
                .tos_hs         = fld_handlers
        },
        {
                .tos_opc_start  = SEQ_FIRST_OPC,
                .tos_opc_end    = SEQ_LAST_OPC,
                .tos_hs         = seq_handlers
        },
        {
                .tos_opc_start  = QUOTA_DQACQ,
                .tos_opc_end    = QUOTA_LAST_OPC,
                .tos_hs         = mdt_quota_ops
        },
        {
                .tos_opc_start  = LLOG_FIRST_OPC,
                .tos_opc_end    = LLOG_LAST_OPC,
                .tos_hs         = tgt_llog_handlers
        },
        {
                .tos_opc_start  = LFSCK_FIRST_OPC,
                .tos_opc_end    = LFSCK_LAST_OPC,
                .tos_hs         = tgt_lfsck_handlers
        },

        {
                .tos_hs         = NULL
        }
};

static void mdt_fini(const struct lu_env *env, struct mdt_device *m)
{
        struct md_device        *next = m->mdt_child;
        struct lu_device        *d    = &m->mdt_lu_dev;
        struct obd_device       *obd  = mdt2obd_dev(m);
        struct lfsck_stop        stop;
        ENTRY;

        stop.ls_status = LS_PAUSED;
        stop.ls_flags = 0;
        next->md_ops->mdo_iocontrol(env, next, OBD_IOC_STOP_LFSCK, 0, &stop);

        target_recovery_fini(obd);
        ping_evictor_stop();
        mdt_stack_pre_fini(env, m, md2lu_dev(m->mdt_child));

        if (m->mdt_opts.mo_coordinator)
                mdt_hsm_cdt_stop(m);

        mdt_hsm_cdt_fini(m);

        mdt_llog_ctxt_unclone(env, m, LLOG_AGENT_ORIG_CTXT);
        mdt_llog_ctxt_unclone(env, m, LLOG_CHANGELOG_ORIG_CTXT);
        obd_exports_barrier(obd);
        obd_zombie_barrier();

        mdt_procfs_fini(m);

        tgt_fini(env, &m->mdt_lut);
        mdt_fs_cleanup(env, m);
        upcall_cache_cleanup(m->mdt_identity_cache);
        m->mdt_identity_cache = NULL;

        if (m->mdt_namespace != NULL) {
                ldlm_namespace_free(m->mdt_namespace, NULL,
                                    d->ld_obd->obd_force);
                d->ld_obd->obd_namespace = m->mdt_namespace = NULL;
        }

        mdt_quota_fini(env, m);

        cfs_free_nidlist(&m->mdt_nosquash_nids);
        if (m->mdt_nosquash_str) {
                OBD_FREE(m->mdt_nosquash_str, m->mdt_nosquash_strlen);
                m->mdt_nosquash_str = NULL;
                m->mdt_nosquash_strlen = 0;
        }

        mdt_seq_fini(env, m);
        mdt_fld_fini(env, m);

        next->md_ops->mdo_init_capa_ctxt(env, next, 0, 0, 0, NULL);
        cfs_timer_disarm(&m->mdt_ck_timer);
        mdt_ck_thread_stop(m);

        /*
         * Finish the stack
         */
        mdt_stack_fini(env, m, md2lu_dev(m->mdt_child));

        LASSERT(atomic_read(&d->ld_ref) == 0);

        server_put_mount(mdt_obd_name(m), true);

        EXIT;
}

static int mdt_postrecov(const struct lu_env *, struct mdt_device *);

static int mdt_init0(const struct lu_env *env, struct mdt_device *m,
                     struct lu_device_type *ldt, struct lustre_cfg *cfg)
{
        struct mdt_thread_info    *info;
        struct obd_device         *obd;
        const char                *dev = lustre_cfg_string(cfg, 0);
        const char                *num = lustre_cfg_string(cfg, 2);
        struct lustre_mount_info  *lmi = NULL;
        struct lustre_sb_info     *lsi;
        struct lu_site            *s;
        struct seq_server_site    *ss_site;
        const char                *identity_upcall = "NONE";
        struct md_device          *next;
        int                        rc;
        long                       node_id;
        mntopt_t                   mntopts;
        ENTRY;

        lu_device_init(&m->mdt_lu_dev, ldt);
        /*
         * Environment (env) might be missing mdt_thread_key values at that
         * point, if device is allocated when mdt_thread_key is in QUIESCENT
         * mode.
         *
         * Usually device allocation path doesn't use module key values, but
         * mdt has to do a lot of work here, so allocate key value.
         */
        rc = lu_env_refill((struct lu_env *)env);
        if (rc != 0)
                RETURN(rc);

        info = lu_context_key_get(&env->le_ctx, &mdt_thread_key);
        LASSERT(info != NULL);

        obd = class_name2obd(dev);
        LASSERT(obd != NULL);

        m->mdt_max_mdsize = MAX_MD_SIZE; /* 4 stripes */

        m->mdt_som_conf = 0;

        m->mdt_opts.mo_cos = MDT_COS_DEFAULT;

        /* default is coordinator off, it is started through conf_param
         * or /proc */
        m->mdt_opts.mo_coordinator = 0;

        lmi = server_get_mount(dev);
        if (lmi == NULL) {
                CERROR("Cannot get mount info for %s!\n", dev);
                RETURN(-EFAULT);
        } else {
                lsi = s2lsi(lmi->lmi_sb);
                /* CMD is supported only in IAM mode */
                LASSERT(num);
                node_id = simple_strtol(num, NULL, 10);
                obd->u.obt.obt_magic = OBT_MAGIC;
        }

        spin_lock_init(&m->mdt_ioepoch_lock);
        m->mdt_capa_timeout = CAPA_TIMEOUT;
        m->mdt_capa_alg = CAPA_HMAC_ALG_SHA1;
        m->mdt_ck_timeout = CAPA_KEY_TIMEOUT;
        m->mdt_squash_uid = 0;
        m->mdt_squash_gid = 0;
        CFS_INIT_LIST_HEAD(&m->mdt_nosquash_nids);
        m->mdt_nosquash_str = NULL;
        m->mdt_nosquash_strlen = 0;
        init_rwsem(&m->mdt_squash_sem);
        spin_lock_init(&m->mdt_osfs_lock);
        m->mdt_osfs_age = cfs_time_shift_64(-1000);
        m->mdt_enable_remote_dir = 0;
        m->mdt_enable_remote_dir_gid = 0;

        m->mdt_lu_dev.ld_ops = &mdt_lu_ops;
        m->mdt_lu_dev.ld_obd = obd;
        /* Set this lu_device to obd for error handling purposes. */
        obd->obd_lu_dev = &m->mdt_lu_dev;

        /* init the stack */
        rc = mdt_stack_init((struct lu_env *)env, m, cfg);
        if (rc) {
                CERROR("%s: Can't init device stack, rc %d\n",
                       mdt_obd_name(m), rc);
                GOTO(err_lmi, rc);
        }

        s = mdt_lu_site(m);
        ss_site = mdt_seq_site(m);
        s->ld_seq_site = ss_site;
        ss_site->ss_lu = s;

        /* set server index */
        ss_site->ss_node_id = node_id;

        /* failover is the default
         * FIXME: we do not failout mds0/mgs, which may cause some problems.
         * assumed whose ss_node_id == 0 XXX
         * */
        obd->obd_replayable = 1;
        /* No connection accepted until configurations will finish */
        obd->obd_no_conn = 1;

        if (cfg->lcfg_bufcount > 4 && LUSTRE_CFG_BUFLEN(cfg, 4) > 0) {
                char *str = lustre_cfg_string(cfg, 4);
                if (strchr(str, 'n')) {
                        CWARN("%s: recovery disabled\n", mdt_obd_name(m));
                        obd->obd_replayable = 0;
                }
        }

        rc = mdt_fld_init(env, mdt_obd_name(m), m);
        if (rc)
                GOTO(err_fini_stack, rc);

        rc = mdt_seq_init(env, m);
        if (rc)
                GOTO(err_fini_fld, rc);

        snprintf(info->mti_u.ns_name, sizeof(info->mti_u.ns_name), "%s-%s",
                 LUSTRE_MDT_NAME, obd->obd_uuid.uuid);
        m->mdt_namespace = ldlm_namespace_new(obd, info->mti_u.ns_name,
                                              LDLM_NAMESPACE_SERVER,
                                              LDLM_NAMESPACE_GREEDY,
                                              LDLM_NS_TYPE_MDT);
        if (m->mdt_namespace == NULL)
                GOTO(err_fini_seq, rc = -ENOMEM);

        m->mdt_namespace->ns_lvbp = m;
        m->mdt_namespace->ns_lvbo = &mdt_lvbo;

        ldlm_register_intent(m->mdt_namespace, mdt_intent_policy);
        /* set obd_namespace for compatibility with old code */
        obd->obd_namespace = m->mdt_namespace;

        cfs_timer_init(&m->mdt_ck_timer, mdt_ck_timer_callback, m);

        rc = mdt_hsm_cdt_init(m);
        if (rc != 0) {
                CERROR("%s: error initializing coordinator, rc %d\n",
                       mdt_obd_name(m), rc);
                GOTO(err_free_ns, rc);
        }

        rc = mdt_ck_thread_start(m);
        if (rc)
                GOTO(err_free_hsm, rc);

        rc = tgt_init(env, &m->mdt_lut, obd, m->mdt_bottom, mdt_common_slice,
                      OBD_FAIL_MDS_ALL_REQUEST_NET,
                      OBD_FAIL_MDS_ALL_REPLY_NET);
        if (rc)
                GOTO(err_capa, rc);

        rc = mdt_fs_setup(env, m, obd, lsi);
        if (rc)
                GOTO(err_tgt, rc);

        tgt_adapt_sptlrpc_conf(&m->mdt_lut, 1);

        next = m->mdt_child;
        rc = next->md_ops->mdo_iocontrol(env, next, OBD_IOC_GET_MNTOPT, 0,
                                         &mntopts);
        if (rc)
                GOTO(err_fs_cleanup, rc);

        if (mntopts & MNTOPT_USERXATTR)
                m->mdt_opts.mo_user_xattr = 1;
        else
                m->mdt_opts.mo_user_xattr = 0;

        rc = next->md_ops->mdo_maxeasize_get(env, next, &m->mdt_max_ea_size);
        if (rc)
                GOTO(err_fs_cleanup, rc);

        if (mntopts & MNTOPT_ACL)
                m->mdt_opts.mo_acl = 1;
        else
                m->mdt_opts.mo_acl = 0;

        /* XXX: to support suppgid for ACL, we enable identity_upcall
         * by default, otherwise, maybe got unexpected -EACCESS. */
        if (m->mdt_opts.mo_acl)
                identity_upcall = MDT_IDENTITY_UPCALL_PATH;

        m->mdt_identity_cache = upcall_cache_init(mdt_obd_name(m),
                                                identity_upcall,
                                                &mdt_identity_upcall_cache_ops);
        if (IS_ERR(m->mdt_identity_cache)) {
                rc = PTR_ERR(m->mdt_identity_cache);
                m->mdt_identity_cache = NULL;
                GOTO(err_fs_cleanup, rc);
        }

        rc = mdt_procfs_init(m, dev);
        if (rc) {
                CERROR("Can't init MDT lprocfs, rc %d\n", rc);
                GOTO(err_recovery, rc);
        }

        rc = mdt_quota_init(env, m, cfg);
        if (rc)
                GOTO(err_procfs, rc);

        m->mdt_ldlm_client = &mdt2obd_dev(m)->obd_ldlm_client;
        ptlrpc_init_client(LDLM_CB_REQUEST_PORTAL, LDLM_CB_REPLY_PORTAL,
                           "mdt_ldlm_client", m->mdt_ldlm_client);

        ping_evictor_start();

        /* recovery will be started upon mdt_prepare()
         * when the whole stack is complete and ready
         * to serve the requests */

        mdt_init_capa_ctxt(env, m);

        /* Reduce the initial timeout on an MDS because it doesn't need such
         * a long timeout as an OST does. Adaptive timeouts will adjust this
         * value appropriately. */
        if (ldlm_timeout == LDLM_TIMEOUT_DEFAULT)
                ldlm_timeout = MDS_LDLM_TIMEOUT_DEFAULT;

        RETURN(0);
err_procfs:
        mdt_procfs_fini(m);
err_recovery:
        target_recovery_fini(obd);
        upcall_cache_cleanup(m->mdt_identity_cache);
        m->mdt_identity_cache = NULL;
err_fs_cleanup:
        mdt_fs_cleanup(env, m);
err_tgt:
        tgt_fini(env, &m->mdt_lut);
err_capa:
        cfs_timer_disarm(&m->mdt_ck_timer);
        mdt_ck_thread_stop(m);
err_free_hsm:
        mdt_hsm_cdt_fini(m);
err_free_ns:
        ldlm_namespace_free(m->mdt_namespace, NULL, 0);
        obd->obd_namespace = m->mdt_namespace = NULL;
err_fini_seq:
        mdt_seq_fini(env, m);
err_fini_fld:
        mdt_fld_fini(env, m);
err_fini_stack:
        mdt_stack_fini(env, m, md2lu_dev(m->mdt_child));
err_lmi:
        if (lmi)
                server_put_mount(dev, true);
        return(rc);
}

/* For interoperability, the left element is old parameter, the right one
 * is the new version of the parameter, if some parameter is deprecated,
 * the new version should be set as NULL. */
static struct cfg_interop_param mdt_interop_param[] = {
        { "mdt.group_upcall",   NULL },
        { "mdt.quota_type",     NULL },
        { "mdd.quota_type",     NULL },
        { "mdt.rootsquash",     "mdt.root_squash" },
        { "mdt.nosquash_nid",   "mdt.nosquash_nids" },
        { NULL }
};

/* used by MGS to process specific configurations */
static int mdt_process_config(const struct lu_env *env,
                              struct lu_device *d, struct lustre_cfg *cfg)
{
        struct mdt_device *m = mdt_dev(d);
        struct md_device *md_next = m->mdt_child;
        struct lu_device *next = md2lu_dev(md_next);
        int rc;
        ENTRY;

        switch (cfg->lcfg_command) {
        case LCFG_PARAM: {
                struct lprocfs_static_vars  lvars;
                struct obd_device          *obd = d->ld_obd;

                /* For interoperability */
                struct cfg_interop_param   *ptr = NULL;
                struct lustre_cfg          *old_cfg = NULL;
                char                       *param = NULL;

                param = lustre_cfg_string(cfg, 1);
                if (param == NULL) {
                        CERROR("param is empty\n");
                        rc = -EINVAL;
                        break;
                }

                ptr = class_find_old_param(param, mdt_interop_param);
                if (ptr != NULL) {
                        if (ptr->new_param == NULL) {
                                rc = 0;
                                CWARN("For interoperability, skip this %s."
                                      " It is obsolete.\n", ptr->old_param);
                                break;
                        }

                        CWARN("Found old param %s, changed it to %s.\n",
                              ptr->old_param, ptr->new_param);

                        old_cfg = cfg;
                        cfg = lustre_cfg_rename(old_cfg, ptr->new_param);
                        if (IS_ERR(cfg)) {
                                rc = PTR_ERR(cfg);
                                break;
                        }
                }

                lprocfs_mdt_init_vars(&lvars);
                rc = class_process_proc_param(PARAM_MDT, lvars.obd_vars,
                                              cfg, obd);
                if (rc > 0 || rc == -ENOSYS) {
                        /* is it an HSM var ? */
                        rc = class_process_proc_param(PARAM_HSM,
                                                      hsm_cdt_get_proc_vars(),
                                                      cfg, obd);
                        if (rc > 0 || rc == -ENOSYS)
                                /* we don't understand; pass it on */
                                rc = next->ld_ops->ldo_process_config(env, next,
                                                                      cfg);
                }

                if (old_cfg != NULL)
                        lustre_cfg_free(cfg);

                break;
        }
        default:
                /* others are passed further */
                rc = next->ld_ops->ldo_process_config(env, next, cfg);
                break;
        }
        RETURN(rc);
}

static struct lu_object *mdt_object_alloc(const struct lu_env *env,
                                          const struct lu_object_header *hdr,
                                          struct lu_device *d)
{
        struct mdt_object *mo;

        ENTRY;

        OBD_SLAB_ALLOC_PTR_GFP(mo, mdt_object_kmem, GFP_NOFS);
        if (mo != NULL) {
                struct lu_object *o;
                struct lu_object_header *h;

                o = &mo->mot_obj;
                h = &mo->mot_header;
                lu_object_header_init(h);
                lu_object_init(o, h, d);
                lu_object_add_top(h, o);
                o->lo_ops = &mdt_obj_ops;
                mutex_init(&mo->mot_ioepoch_mutex);
                mutex_init(&mo->mot_lov_mutex);
                init_rwsem(&mo->mot_open_sem);
                RETURN(o);
        }
        RETURN(NULL);
}

static int mdt_object_init(const struct lu_env *env, struct lu_object *o,
                           const struct lu_object_conf *unused)
{
        struct mdt_device *d = mdt_dev(o->lo_dev);
        struct lu_device  *under;
        struct lu_object  *below;
        int                rc = 0;
        ENTRY;

        CDEBUG(D_INFO, "object init, fid = "DFID"\n",
               PFID(lu_object_fid(o)));

        under = &d->mdt_child->md_lu_dev;
        below = under->ld_ops->ldo_object_alloc(env, o->lo_header, under);
        if (below != NULL) {
                lu_object_add(o, below);
        } else
                rc = -ENOMEM;

        RETURN(rc);
}

static void mdt_object_free(const struct lu_env *env, struct lu_object *o)
{
        struct mdt_object *mo = mdt_obj(o);
        struct lu_object_header *h;
        ENTRY;

        h = o->lo_header;
        CDEBUG(D_INFO, "object free, fid = "DFID"\n",
               PFID(lu_object_fid(o)));

        LASSERT(atomic_read(&mo->mot_open_count) == 0);
        LASSERT(atomic_read(&mo->mot_lease_count) == 0);

        lu_object_fini(o);
        lu_object_header_fini(h);
        OBD_SLAB_FREE_PTR(mo, mdt_object_kmem);

        EXIT;
}

static int mdt_object_print(const struct lu_env *env, void *cookie,
                            lu_printer_t p, const struct lu_object *o)
{
        struct mdt_object *mdto = mdt_obj((struct lu_object *)o);
        return (*p)(env, cookie, LUSTRE_MDT_NAME"-object@%p(ioepoch="LPU64" "
                    "flags="LPX64", epochcount=%d, writecount=%d)",
                    mdto, mdto->mot_ioepoch, mdto->mot_flags,
                    mdto->mot_ioepoch_count, mdto->mot_writecount);
}

static int mdt_prepare(const struct lu_env *env,
                struct lu_device *pdev,
                struct lu_device *cdev)
{
        struct mdt_device *mdt = mdt_dev(cdev);
        struct lu_device *next = &mdt->mdt_child->md_lu_dev;
        struct obd_device *obd = cdev->ld_obd;
        int rc;

        ENTRY;

        LASSERT(obd);

        rc = next->ld_ops->ldo_prepare(env, cdev, next);
        if (rc)
                RETURN(rc);

        rc = mdt_llog_ctxt_clone(env, mdt, LLOG_CHANGELOG_ORIG_CTXT);
        if (rc)
                RETURN(rc);

        rc = mdt_llog_ctxt_clone(env, mdt, LLOG_AGENT_ORIG_CTXT);
        if (rc)
                RETURN(rc);

        rc = lfsck_register_namespace(env, mdt->mdt_bottom, mdt->mdt_namespace);
        /* The LFSCK instance is registered just now, so it must be there when
         * register the namespace to such instance. */
        LASSERTF(rc == 0, "register namespace failed: rc = %d\n", rc);

        if (mdt->mdt_seq_site.ss_node_id == 0) {
                rc = mdt->mdt_child->md_ops->mdo_root_get(env, mdt->mdt_child,
                                                         &mdt->mdt_md_root_fid);
                if (rc)
                        RETURN(rc);
        }

        LASSERT(!test_bit(MDT_FL_CFGLOG, &mdt->mdt_state));
        target_recovery_init(&mdt->mdt_lut, tgt_request_handle);
        set_bit(MDT_FL_CFGLOG, &mdt->mdt_state);
        LASSERT(obd->obd_no_conn);
        spin_lock(&obd->obd_dev_lock);
        obd->obd_no_conn = 0;
        spin_unlock(&obd->obd_dev_lock);

        if (obd->obd_recovering == 0)
                mdt_postrecov(env, mdt);

        RETURN(rc);
}

const struct lu_device_operations mdt_lu_ops = {
        .ldo_object_alloc   = mdt_object_alloc,
        .ldo_process_config = mdt_process_config,
        .ldo_prepare        = mdt_prepare,
};

static const struct lu_object_operations mdt_obj_ops = {
        .loo_object_init    = mdt_object_init,
        .loo_object_free    = mdt_object_free,
        .loo_object_print   = mdt_object_print
};

static int mdt_obd_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)
{
        int rc;

        ENTRY;

        if (KEY_IS(KEY_SPTLRPC_CONF)) {
                rc = tgt_adapt_sptlrpc_conf(class_exp2tgt(exp), 0);
                RETURN(rc);
        }

        RETURN(0);
}

/**
 * Match client and server connection feature flags.
 *
 * Compute the compatibility flags for a connection request based on
 * features mutually supported by client and server.
 *
 * The obd_export::exp_connect_data.ocd_connect_flags field in \a exp
 * must not be updated here, otherwise a partially initialized value may
 * be exposed. After the connection request is successfully processed,
 * the top-level MDT connect request handler atomically updates the export
 * connect flags from the obd_connect_data::ocd_connect_flags field of the
 * reply. \see mdt_connect().
 *
 * \param exp   the obd_export associated with this client/target pair
 * \param mdt   the target device for the connection
 * \param data  stores data for this connect request
 *
 * \retval 0       success
 * \retval -EPROTO \a data unexpectedly has zero obd_connect_data::ocd_brw_size
 * \retval -EBADE  client and server feature requirements are incompatible
 */
static int mdt_connect_internal(struct obd_export *exp,
                                struct mdt_device *mdt,
                                struct obd_connect_data *data)
{
        LASSERT(data != NULL);

        data->ocd_connect_flags &= MDT_CONNECT_SUPPORTED;
        data->ocd_ibits_known &= MDS_INODELOCK_FULL;

        /* If no known bits (which should not happen, probably,
           as everybody should support LOOKUP and UPDATE bits at least)
           revert to compat mode with plain locks. */
        if (!data->ocd_ibits_known &&
            data->ocd_connect_flags & OBD_CONNECT_IBITS)
                data->ocd_connect_flags &= ~OBD_CONNECT_IBITS;

        if (!mdt->mdt_opts.mo_acl)
                data->ocd_connect_flags &= ~OBD_CONNECT_ACL;

        if (!mdt->mdt_opts.mo_user_xattr)
                data->ocd_connect_flags &= ~OBD_CONNECT_XATTR;

        if (!mdt->mdt_som_conf)
                data->ocd_connect_flags &= ~OBD_CONNECT_SOM;

        if (data->ocd_connect_flags & OBD_CONNECT_BRW_SIZE) {
                data->ocd_brw_size = min(data->ocd_brw_size,
                                         (__u32)MD_MAX_BRW_SIZE);
                if (data->ocd_brw_size == 0) {
                        CERROR("%s: cli %s/%p ocd_connect_flags: "LPX64
                               " ocd_version: %x ocd_grant: %d "
                               "ocd_index: %u ocd_brw_size is "
                               "unexpectedly zero, network data "
                               "corruption? Refusing connection of this"
                               " client\n",
                               mdt_obd_name(mdt),
                               exp->exp_client_uuid.uuid,
                               exp, data->ocd_connect_flags, data->ocd_version,
                               data->ocd_grant, data->ocd_index);
                        return -EPROTO;
                }
        }

        /* NB: Disregard the rule against updating
         * exp_connect_data.ocd_connect_flags in this case, since
         * tgt_client_new() needs to know if this is a lightweight
         * connection, and it is safe to expose this flag before
         * connection processing completes. */
        if (data->ocd_connect_flags & OBD_CONNECT_LIGHTWEIGHT) {
                spin_lock(&exp->exp_lock);
                *exp_connect_flags_ptr(exp) |= OBD_CONNECT_LIGHTWEIGHT;
                spin_unlock(&exp->exp_lock);
        }

        data->ocd_version = LUSTRE_VERSION_CODE;

        if ((data->ocd_connect_flags & OBD_CONNECT_FID) == 0) {
                CWARN("%s: MDS requires FID support, but client not\n",
                      mdt_obd_name(mdt));
                return -EBADE;
        }

        if (mdt->mdt_som_conf &&
            !(data->ocd_connect_flags & (OBD_CONNECT_LIGHTWEIGHT |
                                         OBD_CONNECT_MDS_MDS |
                                         OBD_CONNECT_SOM))) {
                CWARN("%s: MDS has SOM enabled, but client does not support "
                      "it\n", mdt_obd_name(mdt));
                return -EBADE;
        }

        if (OCD_HAS_FLAG(data, PINGLESS)) {
                if (ptlrpc_pinger_suppress_pings()) {
                        spin_lock(&exp->exp_obd->obd_dev_lock);
                        list_del_init(&exp->exp_obd_chain_timed);
                        spin_unlock(&exp->exp_obd->obd_dev_lock);
                } else {
                        data->ocd_connect_flags &= ~OBD_CONNECT_PINGLESS;
                }
        }

        data->ocd_max_easize = mdt->mdt_max_ea_size;

        return 0;
}

/* mds_connect copy */
static int mdt_obd_connect(const struct lu_env *env,
                           struct obd_export **exp, struct obd_device *obd,
                           struct obd_uuid *cluuid,
                           struct obd_connect_data *data,
                           void *localdata)
{
        struct obd_export      *lexp;
        struct lustre_handle    conn = { 0 };
        struct mdt_device      *mdt;
        int                     rc;
        ENTRY;

        LASSERT(env != NULL);
        if (!exp || !obd || !cluuid)
                RETURN(-EINVAL);

        mdt = mdt_dev(obd->obd_lu_dev);

        /*
         * first, check whether the stack is ready to handle requests
         * XXX: probably not very appropriate method is used now
         *      at some point we should find a better one
         */
        if (!test_bit(MDT_FL_SYNCED, &mdt->mdt_state) && data != NULL &&
            !(data->ocd_connect_flags & OBD_CONNECT_LIGHTWEIGHT)) {
                rc = obd_get_info(env, mdt->mdt_child_exp,
                                  sizeof(KEY_OSP_CONNECTED),
                                  KEY_OSP_CONNECTED, NULL, NULL, NULL);
                if (rc)
                        RETURN(-EAGAIN);
                set_bit(MDT_FL_SYNCED, &mdt->mdt_state);
        }

        rc = class_connect(&conn, obd, cluuid);
        if (rc)
                RETURN(rc);

        lexp = class_conn2export(&conn);
        LASSERT(lexp != NULL);

        rc = mdt_connect_internal(lexp, mdt, data);
        if (rc == 0) {
                struct lsd_client_data *lcd = lexp->exp_target_data.ted_lcd;

                LASSERT(lcd);
                memcpy(lcd->lcd_uuid, cluuid, sizeof lcd->lcd_uuid);
                rc = tgt_client_new(env, lexp);
                if (rc == 0)
                        mdt_export_stats_init(obd, lexp, localdata);

                /* For phase I, sync for cross-ref operation. */
                lexp->exp_keep_sync = 1;
        }

        if (rc != 0) {
                class_disconnect(lexp);
                *exp = NULL;
        } else {
                *exp = lexp;
        }

        RETURN(rc);
}

static int mdt_obd_reconnect(const struct lu_env *env,
                             struct obd_export *exp, struct obd_device *obd,
                             struct obd_uuid *cluuid,
                             struct obd_connect_data *data,
                             void *localdata)
{
        int                     rc;
        ENTRY;

        if (exp == NULL || obd == NULL || cluuid == NULL)
                RETURN(-EINVAL);

        rc = mdt_connect_internal(exp, mdt_dev(obd->obd_lu_dev), data);
        if (rc == 0)
                mdt_export_stats_init(obd, exp, localdata);

        RETURN(rc);
}

static int mdt_ctxt_add_dirty_flag(struct lu_env *env,
                                   struct mdt_thread_info *info,
                                   struct mdt_file_data *mfd)
{
        struct lu_context ses;
        int rc;
        ENTRY;

        rc = lu_context_init(&ses, LCT_SERVER_SESSION);
        if (rc)
                RETURN(rc);

        env->le_ses = &ses;
        lu_context_enter(&ses);

        mdt_ucred(info)->uc_valid = UCRED_OLD;
        rc = mdt_add_dirty_flag(info, mfd->mfd_object, &info->mti_attr);

        lu_context_exit(&ses);
        lu_context_fini(&ses);
        env->le_ses = NULL;

        RETURN(rc);
}

static int mdt_export_cleanup(struct obd_export *exp)
{
        struct mdt_export_data *med = &exp->exp_mdt_data;
        struct obd_device      *obd = exp->exp_obd;
        struct mdt_device      *mdt;
        struct mdt_thread_info *info;
        struct lu_env           env;
        CFS_LIST_HEAD(closing_list);
        struct mdt_file_data *mfd, *n;
        int rc = 0;
        ENTRY;

        spin_lock(&med->med_open_lock);
        while (!cfs_list_empty(&med->med_open_head)) {
                cfs_list_t *tmp = med->med_open_head.next;
                mfd = cfs_list_entry(tmp, struct mdt_file_data, mfd_list);

                /* Remove mfd handle so it can't be found again.
                 * We are consuming the mfd_list reference here. */
                class_handle_unhash(&mfd->mfd_handle);
                cfs_list_move_tail(&mfd->mfd_list, &closing_list);
        }
        spin_unlock(&med->med_open_lock);
        mdt = mdt_dev(obd->obd_lu_dev);
        LASSERT(mdt != NULL);

        rc = lu_env_init(&env, LCT_MD_THREAD);
        if (rc)
                RETURN(rc);

        info = lu_context_key_get(&env.le_ctx, &mdt_thread_key);
        LASSERT(info != NULL);
        memset(info, 0, sizeof *info);
        info->mti_env = &env;
        info->mti_mdt = mdt;
        info->mti_exp = exp;

        if (!cfs_list_empty(&closing_list)) {
                struct md_attr *ma = &info->mti_attr;

                /* Close any open files (which may also cause orphan unlinking). */
                cfs_list_for_each_entry_safe(mfd, n, &closing_list, mfd_list) {
                        cfs_list_del_init(&mfd->mfd_list);
                        ma->ma_need = ma->ma_valid = 0;

                        /* This file is being closed due to an eviction, it
                         * could have been modified and now dirty regarding to
                         * HSM archive, check this!
                         * The logic here is to mark a file dirty if there's a
                         * chance it was dirtied before the client was evicted,
                         * so that we don't have to wait for a release attempt
                         * before finding out the file was actually dirty and
                         * fail the release. Aggressively marking it dirty here
                         * will cause the policy engine to attempt to
                         * re-archive it; when rearchiving, we can compare the
                         * current version to the HSM data_version and make the
                         * archive request into a noop if it's not actually
                         * dirty.
                         */
                        if (mfd->mfd_mode & (FMODE_WRITE|MDS_FMODE_TRUNC))
                                rc = mdt_ctxt_add_dirty_flag(&env, info, mfd);

                        /* Don't unlink orphan on failover umount, LU-184 */
                        if (exp->exp_flags & OBD_OPT_FAILOVER) {
                                ma->ma_valid = MA_FLAGS;
                                ma->ma_attr_flags |= MDS_KEEP_ORPHAN;
                        }
                        mdt_mfd_close(info, mfd);
                }
        }
        info->mti_mdt = NULL;
        /* cleanup client slot early */
        /* Do not erase record for recoverable client. */
        if (!(exp->exp_flags & OBD_OPT_FAILOVER) || exp->exp_failed)
                tgt_client_del(&env, exp);
        lu_env_fini(&env);

        RETURN(rc);
}

static int mdt_obd_disconnect(struct obd_export *exp)
{
        int rc;
        ENTRY;

        LASSERT(exp);
        class_export_get(exp);

        rc = server_disconnect_export(exp);
        if (rc != 0)
                CDEBUG(D_IOCTL, "server disconnect error: %d\n", rc);

        rc = mdt_export_cleanup(exp);
        class_export_put(exp);
        RETURN(rc);
}

/* FIXME: Can we avoid using these two interfaces? */
static int mdt_init_export(struct obd_export *exp)
{
        struct mdt_export_data *med = &exp->exp_mdt_data;
        int                     rc;
        ENTRY;

        CFS_INIT_LIST_HEAD(&med->med_open_head);
        spin_lock_init(&med->med_open_lock);
        mutex_init(&med->med_idmap_mutex);
        med->med_idmap = NULL;
        spin_lock(&exp->exp_lock);
        exp->exp_connecting = 1;
        spin_unlock(&exp->exp_lock);

        /* self-export doesn't need client data and ldlm initialization */
        if (unlikely(obd_uuid_equals(&exp->exp_obd->obd_uuid,
                                     &exp->exp_client_uuid)))
                RETURN(0);

        rc = tgt_client_alloc(exp);
        if (rc)
                GOTO(err, rc);

        rc = ldlm_init_export(exp);
        if (rc)
                GOTO(err_free, rc);

        RETURN(rc);

err_free:
        tgt_client_free(exp);
err:
        CERROR("%s: Failed to initialize export: rc = %d\n",
               exp->exp_obd->obd_name, rc);
        return rc;
}

static int mdt_destroy_export(struct obd_export *exp)
{
        ENTRY;

        if (exp_connect_rmtclient(exp))
                mdt_cleanup_idmap(&exp->exp_mdt_data);

        target_destroy_export(exp);
        /* destroy can be called from failed obd_setup, so
         * checking uuid is safer than obd_self_export */
        if (unlikely(obd_uuid_equals(&exp->exp_obd->obd_uuid,
                                     &exp->exp_client_uuid)))
                RETURN(0);

        ldlm_destroy_export(exp);
        tgt_client_free(exp);

        LASSERT(cfs_list_empty(&exp->exp_outstanding_replies));
        LASSERT(cfs_list_empty(&exp->exp_mdt_data.med_open_head));

        RETURN(0);
}

/** The maximum depth that fid2path() will search.
 * This is limited only because we want to store the fids for
 * historical path lookup purposes.
 */
#define MAX_PATH_DEPTH 100

/** mdt_path() lookup structure. */
struct path_lookup_info {
        __u64                   pli_recno;      /**< history point */
        __u64                   pli_currec;     /**< current record */
        struct lu_fid           pli_fid;
        struct lu_fid           pli_fids[MAX_PATH_DEPTH]; /**< path, in fids */
        struct mdt_object       *pli_mdt_obj;
        char                    *pli_path;      /**< full path */
        int                     pli_pathlen;
        int                     pli_linkno;     /**< which hardlink to follow */
        int                     pli_fidcount;   /**< number of \a pli_fids */
};

int mdt_links_read(struct mdt_thread_info *info, struct mdt_object *mdt_obj,
                   struct linkea_data *ldata)
{
        int rc;

        LASSERT(ldata->ld_buf->lb_buf != NULL);

        if (!mdt_object_exists(mdt_obj))
                return -ENODATA;

        rc = mo_xattr_get(info->mti_env, mdt_object_child(mdt_obj),
                          ldata->ld_buf, XATTR_NAME_LINK);
        if (rc == -ERANGE) {
                /* Buf was too small, figure out what we need. */
                lu_buf_free(ldata->ld_buf);
                rc = mo_xattr_get(info->mti_env, mdt_object_child(mdt_obj),
                                  ldata->ld_buf, XATTR_NAME_LINK);
                if (rc < 0)
                        return rc;
                ldata->ld_buf = lu_buf_check_and_alloc(ldata->ld_buf, rc);
                if (ldata->ld_buf->lb_buf == NULL)
                        return -ENOMEM;
                rc = mo_xattr_get(info->mti_env, mdt_object_child(mdt_obj),
                                  ldata->ld_buf, XATTR_NAME_LINK);
        }
        if (rc < 0)
                return rc;

        return linkea_init(ldata);
}

static int mdt_path_current(struct mdt_thread_info *info,
                            struct path_lookup_info *pli)
{
        struct mdt_device       *mdt = info->mti_mdt;
        struct mdt_object       *mdt_obj;
        struct link_ea_header   *leh;
        struct link_ea_entry    *lee;
        struct lu_name          *tmpname = &info->mti_name;
        struct lu_fid           *tmpfid = &info->mti_tmp_fid1;
        struct lu_buf           *buf = &info->mti_big_buf;
        char                    *ptr;
        int                     reclen;
        struct linkea_data      ldata = { 0 };
        int                     rc = 0;
        ENTRY;

        /* temp buffer for path element, the buffer will be finally freed
         * in mdt_thread_info_fini */
        buf = lu_buf_check_and_alloc(buf, PATH_MAX);
        if (buf->lb_buf == NULL)
                RETURN(-ENOMEM);

        ldata.ld_buf = buf;
        ptr = pli->pli_path + pli->pli_pathlen - 1;
        *ptr = 0;
        --ptr;
        pli->pli_fidcount = 0;
        pli->pli_fids[0] = *(struct lu_fid *)mdt_object_fid(pli->pli_mdt_obj);

        /* root FID only exists on MDT0, and fid2path should also ends at MDT0,
         * so checking root_fid can only happen on MDT0. */
        while (!lu_fid_eq(&mdt->mdt_md_root_fid,
                          &pli->pli_fids[pli->pli_fidcount])) {
                mdt_obj = mdt_object_find(info->mti_env, mdt,
                                          &pli->pli_fids[pli->pli_fidcount]);
                if (IS_ERR(mdt_obj))
                        GOTO(out, rc = PTR_ERR(mdt_obj));
                if (mdt_object_remote(mdt_obj)) {
                        mdt_object_put(info->mti_env, mdt_obj);
                        GOTO(remote_out, rc = -EREMOTE);
                }
                if (!mdt_object_exists(mdt_obj)) {
                        mdt_object_put(info->mti_env, mdt_obj);
                        GOTO(out, rc = -ENOENT);
                }

                rc = mdt_links_read(info, mdt_obj, &ldata);
                mdt_object_put(info->mti_env, mdt_obj);
                if (rc != 0)
                        GOTO(out, rc);

                leh = buf->lb_buf;
                lee = (struct link_ea_entry *)(leh + 1); /* link #0 */
                linkea_entry_unpack(lee, &reclen, tmpname, tmpfid);
                /* If set, use link #linkno for path lookup, otherwise use
                   link #0.  Only do this for the final path element. */
                if (pli->pli_fidcount == 0 &&
                    pli->pli_linkno < leh->leh_reccount) {
                        int count;
                        for (count = 0; count < pli->pli_linkno; count++) {
                                lee = (struct link_ea_entry *)
                                     ((char *)lee + reclen);
                                linkea_entry_unpack(lee, &reclen, tmpname,
                                                    tmpfid);
                        }
                        if (pli->pli_linkno < leh->leh_reccount - 1)
                                /* indicate to user there are more links */
                                pli->pli_linkno++;
                }

                /* Pack the name in the end of the buffer */
                ptr -= tmpname->ln_namelen;
                if (ptr - 1 <= pli->pli_path)
                        GOTO(out, rc = -EOVERFLOW);
                strncpy(ptr, tmpname->ln_name, tmpname->ln_namelen);
                *(--ptr) = '/';

                /* Store the parent fid for historic lookup */
                if (++pli->pli_fidcount >= MAX_PATH_DEPTH)
                        GOTO(out, rc = -EOVERFLOW);
                pli->pli_fids[pli->pli_fidcount] = *tmpfid;
        }

remote_out:
        ptr++; /* skip leading / */
        memmove(pli->pli_path, ptr, pli->pli_path + pli->pli_pathlen - ptr);

        EXIT;
out:
        return rc;
}

/* Returns the full path to this fid, as of changelog record recno. */
static int mdt_path(struct mdt_thread_info *info, struct mdt_object *obj,
                    char *path, int pathlen, __u64 *recno, int *linkno,
                    struct lu_fid *fid)
{
        struct mdt_device       *mdt = info->mti_mdt;
        struct path_lookup_info *pli;
        int                     tries = 3;
        int                     rc = -EAGAIN;
        ENTRY;

        if (pathlen < 3)
                RETURN(-EOVERFLOW);

        if (lu_fid_eq(&mdt->mdt_md_root_fid, mdt_object_fid(obj))) {
                path[0] = '\0';
                RETURN(0);
        }

        OBD_ALLOC_PTR(pli);
        if (pli == NULL)
                RETURN(-ENOMEM);

        pli->pli_mdt_obj = obj;
        pli->pli_recno = *recno;
        pli->pli_path = path;
        pli->pli_pathlen = pathlen;
        pli->pli_linkno = *linkno;

        /* Retry multiple times in case file is being moved */
        while (tries-- && rc == -EAGAIN)
                rc = mdt_path_current(info, pli);

        /* return the last resolved fids to the client, so the client will
         * build the left path on another MDT for remote object */
        *fid = pli->pli_fids[pli->pli_fidcount];

        *recno = pli->pli_currec;
        /* Return next link index to caller */
        *linkno = pli->pli_linkno;

        OBD_FREE_PTR(pli);

        RETURN(rc);
}

static int mdt_fid2path(struct mdt_thread_info *info,
                        struct getinfo_fid2path *fp)
{
        struct mdt_device *mdt = info->mti_mdt;
        struct mdt_object *obj;
        int    rc;
        ENTRY;

        CDEBUG(D_IOCTL, "path get "DFID" from "LPU64" #%d\n",
                PFID(&fp->gf_fid), fp->gf_recno, fp->gf_linkno);

        if (!fid_is_sane(&fp->gf_fid))
                RETURN(-EINVAL);

        if (!fid_is_namespace_visible(&fp->gf_fid)) {
                CWARN("%s: "DFID" is invalid, sequence should be "
                      ">= "LPX64"\n", mdt_obd_name(mdt),
                      PFID(&fp->gf_fid), (__u64)FID_SEQ_NORMAL);
                RETURN(-EINVAL);
        }

        obj = mdt_object_find(info->mti_env, mdt, &fp->gf_fid);
        if (obj == NULL || IS_ERR(obj)) {
                CDEBUG(D_IOCTL, "no object "DFID": %ld\n", PFID(&fp->gf_fid),
                       PTR_ERR(obj));
                RETURN(-EINVAL);
        }

        if (mdt_object_remote(obj))
                rc = -EREMOTE;
        else if (!mdt_object_exists(obj))
                rc = -ENOENT;
        else
                rc = 0;

        if (rc < 0) {
                mdt_object_put(info->mti_env, obj);
                CDEBUG(D_IOCTL, "nonlocal object "DFID": %d\n",
                       PFID(&fp->gf_fid), rc);
                RETURN(rc);
        }

        rc = mdt_path(info, obj, fp->gf_path, fp->gf_pathlen, &fp->gf_recno,
                      &fp->gf_linkno, &fp->gf_fid);

        CDEBUG(D_INFO, "fid "DFID", path %s recno "LPX64" linkno %u\n",
               PFID(&fp->gf_fid), fp->gf_path, fp->gf_recno, fp->gf_linkno);

        mdt_object_put(info->mti_env, obj);

        RETURN(rc);
}

static int mdt_rpc_fid2path(struct mdt_thread_info *info, void *key,
                            void *val, int vallen)
{
        struct getinfo_fid2path *fpout, *fpin;
        int rc = 0;

        fpin = key + cfs_size_round(sizeof(KEY_FID2PATH));
        fpout = val;

        if (ptlrpc_req_need_swab(info->mti_pill->rc_req))
                lustre_swab_fid2path(fpin);

        memcpy(fpout, fpin, sizeof(*fpin));
        if (fpout->gf_pathlen != vallen - sizeof(*fpin))
                RETURN(-EINVAL);

        rc = mdt_fid2path(info, fpout);
        RETURN(rc);
}

int mdt_get_info(struct tgt_session_info *tsi)
{
        char    *key;
        int      keylen;
        __u32   *vallen;
        void    *valout;
        int      rc;

        ENTRY;

        key = req_capsule_client_get(tsi->tsi_pill, &RMF_GETINFO_KEY);
        if (key == NULL) {
                CDEBUG(D_IOCTL, "No GETINFO key");
                RETURN(err_serious(-EFAULT));
        }
        keylen = req_capsule_get_size(tsi->tsi_pill, &RMF_GETINFO_KEY,
                                      RCL_CLIENT);

        vallen = req_capsule_client_get(tsi->tsi_pill, &RMF_GETINFO_VALLEN);
        if (vallen == NULL) {
                CDEBUG(D_IOCTL, "Unable to get RMF_GETINFO_VALLEN buffer");
                RETURN(err_serious(-EFAULT));
        }

        req_capsule_set_size(tsi->tsi_pill, &RMF_GETINFO_VAL, RCL_SERVER,
                             *vallen);
        rc = req_capsule_server_pack(tsi->tsi_pill);
        if (rc)
                RETURN(err_serious(rc));

        valout = req_capsule_server_get(tsi->tsi_pill, &RMF_GETINFO_VAL);
        if (valout == NULL) {
                CDEBUG(D_IOCTL, "Unable to get get-info RPC out buffer");
                RETURN(err_serious(-EFAULT));
        }

        if (KEY_IS(KEY_FID2PATH)) {
                struct mdt_thread_info  *info = tsi2mdt_info(tsi);

                rc = mdt_rpc_fid2path(info, key, valout, *vallen);
                mdt_thread_info_fini(info);
        } else {
                rc = -EINVAL;
        }
        RETURN(rc);
}

/* Pass the ioc down */
static int mdt_ioc_child(struct lu_env *env, struct mdt_device *mdt,
                         unsigned int cmd, int len, void *data)
{
        struct lu_context ioctl_session;
        struct md_device *next = mdt->mdt_child;
        int rc;
        ENTRY;

        rc = lu_context_init(&ioctl_session, LCT_SERVER_SESSION);
        if (rc)
                RETURN(rc);
        ioctl_session.lc_thread = (struct ptlrpc_thread *)current;
        lu_context_enter(&ioctl_session);
        env->le_ses = &ioctl_session;

        LASSERT(next->md_ops->mdo_iocontrol);
        rc = next->md_ops->mdo_iocontrol(env, next, cmd, len, data);

        lu_context_exit(&ioctl_session);
        lu_context_fini(&ioctl_session);
        RETURN(rc);
}

static int mdt_ioc_version_get(struct mdt_thread_info *mti, void *karg)
{
        struct obd_ioctl_data *data = karg;
        struct lu_fid *fid;
        __u64 version;
        struct mdt_object *obj;
        struct mdt_lock_handle  *lh;
        int rc;
        ENTRY;

        if (data->ioc_inlbuf1 == NULL || data->ioc_inllen1 != sizeof(*fid) ||
            data->ioc_inlbuf2 == NULL || data->ioc_inllen2 != sizeof(version))
                RETURN(-EINVAL);

        fid = (struct lu_fid *)data->ioc_inlbuf1;

        if (!fid_is_sane(fid))
                RETURN(-EINVAL);

        CDEBUG(D_IOCTL, "getting version for "DFID"\n", PFID(fid));

        lh = &mti->mti_lh[MDT_LH_PARENT];
        mdt_lock_reg_init(lh, LCK_CR);

        obj = mdt_object_find_lock(mti, fid, lh, MDS_INODELOCK_UPDATE);
        if (IS_ERR(obj))
                RETURN(PTR_ERR(obj));

        if (mdt_object_remote(obj)) {
                rc = -EREMOTE;
                /**
                 * before calling version get the correct MDS should be
                 * fid, this is error to find remote object here
                 */
                CERROR("nonlocal object "DFID"\n", PFID(fid));
        } else if (!mdt_object_exists(obj)) {
                *(__u64 *)data->ioc_inlbuf2 = ENOENT_VERSION;
                rc = -ENOENT;
        } else {
                version = dt_version_get(mti->mti_env, mdt_obj2dt(obj));
               *(__u64 *)data->ioc_inlbuf2 = version;
                rc = 0;
        }
        mdt_object_unlock_put(mti, obj, lh, 1);
        RETURN(rc);
}

/* ioctls on obd dev */
static int mdt_iocontrol(unsigned int cmd, struct obd_export *exp, int len,
                         void *karg, void *uarg)
{
        struct lu_env      env;
        struct obd_device *obd = exp->exp_obd;
        struct mdt_device *mdt = mdt_dev(obd->obd_lu_dev);
        struct dt_device  *dt = mdt->mdt_bottom;
        int rc;

        ENTRY;
        CDEBUG(D_IOCTL, "handling ioctl cmd %#x\n", cmd);
        rc = lu_env_init(&env, LCT_MD_THREAD);
        if (rc)
                RETURN(rc);

        switch (cmd) {
        case OBD_IOC_SYNC:
                rc = mdt_device_sync(&env, mdt);
                break;
        case OBD_IOC_SET_READONLY:
                rc = dt->dd_ops->dt_ro(&env, dt);
                break;
        case OBD_IOC_ABORT_RECOVERY:
                CERROR("%s: Aborting recovery for device\n", mdt_obd_name(mdt));
                target_stop_recovery_thread(obd);
                rc = 0;
                break;
        case OBD_IOC_CHANGELOG_REG:
        case OBD_IOC_CHANGELOG_DEREG:
        case OBD_IOC_CHANGELOG_CLEAR:
                rc = mdt_ioc_child(&env, mdt, cmd, len, karg);
                break;
        case OBD_IOC_START_LFSCK: {
                struct md_device *next = mdt->mdt_child;
                struct obd_ioctl_data *data = karg;
                struct lfsck_start_param lsp;

                if (unlikely(data == NULL)) {
                        rc = -EINVAL;
                        break;
                }

                lsp.lsp_start = (struct lfsck_start *)(data->ioc_inlbuf1);
                lsp.lsp_index_valid = 0;
                rc = next->md_ops->mdo_iocontrol(&env, next, cmd, 0, &lsp);
                break;
        }
        case OBD_IOC_STOP_LFSCK: {
                struct md_device        *next = mdt->mdt_child;
                struct obd_ioctl_data   *data = karg;
                struct lfsck_stop        stop;

                stop.ls_status = LS_STOPPED;
                /* Old lfsck utils may pass NULL @stop. */
                if (data->ioc_inlbuf1 == NULL)
                        stop.ls_flags = 0;
                else
                        stop.ls_flags =
                        ((struct lfsck_stop *)(data->ioc_inlbuf1))->ls_flags;

                rc = next->md_ops->mdo_iocontrol(&env, next, cmd, 0, &stop);
                break;
        }
        case OBD_IOC_GET_OBJ_VERSION: {
                struct mdt_thread_info *mti;
                mti = lu_context_key_get(&env.le_ctx, &mdt_thread_key);
                memset(mti, 0, sizeof *mti);
                mti->mti_env = &env;
                mti->mti_mdt = mdt;
                mti->mti_exp = exp;

                rc = mdt_ioc_version_get(mti, karg);
                break;
        }
        case OBD_IOC_CATLOGLIST: {
                struct mdt_thread_info *mti;

                mti = lu_context_key_get(&env.le_ctx, &mdt_thread_key);
                lu_local_obj_fid(&mti->mti_tmp_fid1, LLOG_CATALOGS_OID);
                rc = llog_catalog_list(&env, mdt->mdt_bottom, 0, karg,
                                       &mti->mti_tmp_fid1);
                break;
         }
        default:
                rc = -EOPNOTSUPP;
                CERROR("%s: Not supported cmd = %d, rc = %d\n",
                        mdt_obd_name(mdt), cmd, rc);
        }

        lu_env_fini(&env);
        RETURN(rc);
}

static int mdt_postrecov(const struct lu_env *env, struct mdt_device *mdt)
{
        struct lu_device *ld = md2lu_dev(mdt->mdt_child);
        struct lfsck_start_param lsp;
        int rc;
        ENTRY;

        lsp.lsp_start = NULL;
        lsp.lsp_index_valid = 0;
        rc = mdt->mdt_child->md_ops->mdo_iocontrol(env, mdt->mdt_child,
                                                   OBD_IOC_START_LFSCK,
                                                   0, &lsp);
        if (rc != 0 && rc != -EALREADY)
                CWARN("%s: auto trigger paused LFSCK failed: rc = %d\n",
                      mdt_obd_name(mdt), rc);

        rc = ld->ld_ops->ldo_recovery_complete(env, ld);
        RETURN(rc);
}

static int mdt_obd_postrecov(struct obd_device *obd)
{
        struct lu_env env;
        int rc;

        rc = lu_env_init(&env, LCT_MD_THREAD);
        if (rc)
                RETURN(rc);
        rc = mdt_postrecov(&env, mdt_dev(obd->obd_lu_dev));
        lu_env_fini(&env);
        return rc;
}

static struct obd_ops mdt_obd_device_ops = {
        .o_owner          = THIS_MODULE,
        .o_set_info_async = mdt_obd_set_info_async,
        .o_connect        = mdt_obd_connect,
        .o_reconnect      = mdt_obd_reconnect,
        .o_disconnect     = mdt_obd_disconnect,
        .o_init_export    = mdt_init_export,
        .o_destroy_export = mdt_destroy_export,
        .o_iocontrol      = mdt_iocontrol,
        .o_postrecov      = mdt_obd_postrecov,
};

static struct lu_device* mdt_device_fini(const struct lu_env *env,
                                         struct lu_device *d)
{
        struct mdt_device *m = mdt_dev(d);
        ENTRY;

        mdt_fini(env, m);
        RETURN(NULL);
}

static struct lu_device *mdt_device_free(const struct lu_env *env,
                                         struct lu_device *d)
{
        struct mdt_device *m = mdt_dev(d);
        ENTRY;

        lu_device_fini(&m->mdt_lu_dev);
        OBD_FREE_PTR(m);

        RETURN(NULL);
}

static struct lu_device *mdt_device_alloc(const struct lu_env *env,
                                          struct lu_device_type *t,
                                          struct lustre_cfg *cfg)
{
        struct lu_device  *l;
        struct mdt_device *m;

        OBD_ALLOC_PTR(m);
        if (m != NULL) {
                int rc;

                l = &m->mdt_lu_dev;
                rc = mdt_init0(env, m, t, cfg);
                if (rc != 0) {
                        mdt_device_free(env, l);
                        l = ERR_PTR(rc);
                        return l;
                }
        } else
                l = ERR_PTR(-ENOMEM);
        return l;
}

/* context key constructor/destructor: mdt_key_init, mdt_key_fini */
LU_KEY_INIT(mdt, struct mdt_thread_info);

static void mdt_key_fini(const struct lu_context *ctx,
                         struct lu_context_key *key, void* data)
{
        struct mdt_thread_info *info = data;

        if (info->mti_big_lmm) {
                OBD_FREE_LARGE(info->mti_big_lmm, info->mti_big_lmmsize);
                info->mti_big_lmm = NULL;
                info->mti_big_lmmsize = 0;
        }
        OBD_FREE_PTR(info);
}

/* context key: mdt_thread_key */
LU_CONTEXT_KEY_DEFINE(mdt, LCT_MD_THREAD);

struct lu_ucred *mdt_ucred(const struct mdt_thread_info *info)
{
        return lu_ucred(info->mti_env);
}

struct lu_ucred *mdt_ucred_check(const struct mdt_thread_info *info)
{
        return lu_ucred_check(info->mti_env);
}

/**
 * Enable/disable COS (Commit On Sharing).
 *
 * Set/Clear the COS flag in mdt options.
 *
 * \param mdt mdt device
 * \param val 0 disables COS, other values enable COS
 */
void mdt_enable_cos(struct mdt_device *mdt, int val)
{
        struct lu_env env;
        int rc;

        mdt->mdt_opts.mo_cos = !!val;
        rc = lu_env_init(&env, LCT_LOCAL);
        if (unlikely(rc != 0)) {
                CWARN("lu_env initialization failed with rc = %d,"
                      "cannot sync\n", rc);
                return;
        }
        mdt_device_sync(&env, mdt);
        lu_env_fini(&env);
}

/**
 * Check COS (Commit On Sharing) status.
 *
 * Return COS flag status.
 *
 * \param mdt mdt device
 */
int mdt_cos_is_enabled(struct mdt_device *mdt)
{
        return mdt->mdt_opts.mo_cos != 0;
}

static struct lu_device_type_operations mdt_device_type_ops = {
        .ldto_device_alloc = mdt_device_alloc,
        .ldto_device_free  = mdt_device_free,
        .ldto_device_fini  = mdt_device_fini
};

static struct lu_device_type mdt_device_type = {
        .ldt_tags     = LU_DEVICE_MD,
        .ldt_name     = LUSTRE_MDT_NAME,
        .ldt_ops      = &mdt_device_type_ops,
        .ldt_ctx_tags = LCT_MD_THREAD
};

static int __init mdt_mod_init(void)
{
        struct lprocfs_static_vars lvars;
        int rc;

        CLASSERT(sizeof("0x0123456789ABCDEF:0x01234567:0x01234567") ==
                 FID_NOBRACE_LEN + 1);
        CLASSERT(sizeof("[0x0123456789ABCDEF:0x01234567:0x01234567]") ==
                 FID_LEN + 1);
        rc = lu_kmem_init(mdt_caches);
        if (rc)
                return rc;

        rc = mds_mod_init();
        if (rc)
                GOTO(lu_fini, rc);

        lprocfs_mdt_init_vars(&lvars);
        rc = class_register_type(&mdt_obd_device_ops, NULL, true, NULL,
#ifndef HAVE_ONLY_PROCFS_SEQ
                                 lvars.module_vars,
#endif
                                 LUSTRE_MDT_NAME, &mdt_device_type);
        if (rc)
                GOTO(mds_fini, rc);
lu_fini:
        if (rc)
                lu_kmem_fini(mdt_caches);
mds_fini:
        if (rc)
                mds_mod_exit();
        return rc;
}

static void __exit mdt_mod_exit(void)
{
        class_unregister_type(LUSTRE_MDT_NAME);
        mds_mod_exit();
        lu_kmem_fini(mdt_caches);
}

MODULE_AUTHOR("Sun Microsystems, Inc. <http://www.lustre.org/>");
MODULE_DESCRIPTION("Lustre Metadata Target ("LUSTRE_MDT_NAME")");
MODULE_LICENSE("GPL");

cfs_module(mdt, LUSTRE_VERSION_STRING, mdt_mod_init, mdt_mod_exit);