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LU-3538 dne: Commit-on-Sharing for DNE
[fs/lustre-release.git] / lustre / mdt / mdt_reint.c
index d18019b..5aac290 100644 (file)
@@ -292,131 +292,16 @@ static int mdt_remote_permission(struct mdt_thread_info *info)
        return 0;
 }
 
-/*
- * VBR: we save three versions in reply:
- * 0 - parent. Check that parent version is the same during replay.
- * 1 - name. Version of 'name' if file exists with the same name or
- * ENOENT_VERSION, it is needed because file may appear due to missed replays.
- * 2 - child. Version of child by FID. Must be ENOENT. It is mostly sanity
- * check.
- */
-static int mdt_md_create(struct mdt_thread_info *info)
-{
-        struct mdt_device       *mdt = info->mti_mdt;
-        struct mdt_object       *parent;
-        struct mdt_object       *child;
-        struct mdt_lock_handle  *lh;
-        struct mdt_body         *repbody;
-        struct md_attr          *ma = &info->mti_attr;
-        struct mdt_reint_record *rr = &info->mti_rr;
-        int rc;
-        ENTRY;
-
-       DEBUG_REQ(D_INODE, mdt_info_req(info), "Create  ("DNAME"->"DFID") "
-                 "in "DFID,
-                 PNAME(&rr->rr_name), PFID(rr->rr_fid2), PFID(rr->rr_fid1));
-
-       if (!fid_is_md_operative(rr->rr_fid1))
-               RETURN(-EPERM);
-
-       repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
-
-       parent = mdt_object_find(info->mti_env, info->mti_mdt, rr->rr_fid1);
-       if (IS_ERR(parent))
-               RETURN(PTR_ERR(parent));
-
-       if (!mdt_object_exists(parent))
-               GOTO(put_parent, rc = -ENOENT);
-
-       lh = &info->mti_lh[MDT_LH_PARENT];
-       mdt_lock_pdo_init(lh, LCK_PW, &rr->rr_name);
-       rc = mdt_object_lock(info, parent, lh, MDS_INODELOCK_UPDATE);
-       if (rc)
-               GOTO(put_parent, rc);
-
-       if (!mdt_object_remote(parent)) {
-               rc = mdt_version_get_check_save(info, parent, 0);
-               if (rc)
-                       GOTO(unlock_parent, rc);
-       }
-
-       /*
-        * Check child name version during replay.
-        * During create replay a file may exist with same name.
-        */
-       rc = mdt_lookup_version_check(info, parent, &rr->rr_name,
-                                     &info->mti_tmp_fid1, 1);
-       if (rc == 0)
-               GOTO(unlock_parent, rc = -EEXIST);
-
-       /* -ENOENT is expected here */
-       if (rc != -ENOENT)
-               GOTO(unlock_parent, rc);
-
-       /* save version of file name for replay, it must be ENOENT here */
-       mdt_enoent_version_save(info, 1);
-
-       child = mdt_object_new(info->mti_env, mdt, rr->rr_fid2);
-        if (likely(!IS_ERR(child))) {
-                struct md_object *next = mdt_object_child(parent);
-
-               rc = mdt_remote_permission(info);
-               if (rc != 0)
-                       GOTO(out_put_child, rc);
-
-               ma->ma_need = MA_INODE;
-                ma->ma_valid = 0;
-
-                mdt_fail_write(info->mti_env, info->mti_mdt->mdt_bottom,
-                               OBD_FAIL_MDS_REINT_CREATE_WRITE);
-
-                /* Version of child will be updated on disk. */
-               tgt_vbr_obj_set(info->mti_env, mdt_obj2dt(child));
-                rc = mdt_version_get_check_save(info, child, 2);
-                if (rc)
-                        GOTO(out_put_child, rc);
-
-                /* Let lower layer know current lock mode. */
-                info->mti_spec.sp_cr_mode =
-                        mdt_dlm_mode2mdl_mode(lh->mlh_pdo_mode);
-
-               /*
-                * Do not perform lookup sanity check. We know that name does
-                * not exist.
-                */
-               info->mti_spec.sp_cr_lookup = 0;
-                info->mti_spec.sp_feat = &dt_directory_features;
-
-               rc = mdo_create(info->mti_env, next, &rr->rr_name,
-                               mdt_object_child(child), &info->mti_spec, ma);
-               if (rc == 0)
-                       rc = mdt_attr_get_complex(info, child, ma);
-
-               if (rc == 0) {
-                       /* Return fid & attr to client. */
-                       if (ma->ma_valid & MA_INODE)
-                               mdt_pack_attr2body(info, repbody, &ma->ma_attr,
-                                                  mdt_object_fid(child));
-               }
-out_put_child:
-               mdt_object_put(info->mti_env, child);
-       } else {
-               rc = PTR_ERR(child);
-       }
-unlock_parent:
-       mdt_object_unlock(info, parent, lh, rc);
-put_parent:
-       mdt_object_put(info->mti_env, parent);
-       RETURN(rc);
-}
-
 static int mdt_unlock_slaves(struct mdt_thread_info *mti,
                             struct mdt_object *obj, __u64 ibits,
                             struct mdt_lock_handle *s0_lh,
                             struct mdt_object *s0_obj,
-                            struct ldlm_enqueue_info *einfo)
+                            struct ldlm_enqueue_info *einfo,
+                            int decref)
 {
        union ldlm_policy_data *policy = &mti->mti_policy;
+       struct lustre_handle_array *slave_locks = einfo->ei_cbdata;
+       int i;
        int rc;
        ENTRY;
 
@@ -426,31 +311,33 @@ static int mdt_unlock_slaves(struct mdt_thread_info *mti,
        /* Unlock stripe 0 */
        if (s0_lh != NULL && lustre_handle_is_used(&s0_lh->mlh_reg_lh)) {
                LASSERT(s0_obj != NULL);
-               mdt_object_unlock_put(mti, s0_obj, s0_lh, 1);
+               mdt_object_unlock_put(mti, s0_obj, s0_lh, decref);
        }
 
        memset(policy, 0, sizeof(*policy));
        policy->l_inodebits.bits = ibits;
 
+       if (slave_locks != NULL) {
+               LASSERT(s0_lh != NULL);
+               for (i = 1; i < slave_locks->count; i++) {
+                       /* borrow s0_lh temporarily to do mdt unlock */
+                       mdt_lock_reg_init(s0_lh, einfo->ei_mode);
+                       s0_lh->mlh_rreg_lh = slave_locks->handles[i];
+                       mdt_object_unlock(mti, obj, s0_lh, decref);
+                       slave_locks->handles[i].cookie = 0ull;
+               }
+       }
+
        rc = mo_object_unlock(mti->mti_env, mdt_object_child(obj), einfo,
                              policy);
        RETURN(rc);
 }
 
-/**
- * Lock slave stripes if necessary, the lock handles of slave stripes
- * will be stored in einfo->ei_cbdata.
- **/
-static int mdt_lock_slaves(struct mdt_thread_info *mti, struct mdt_object *obj,
-                          enum ldlm_mode mode, __u64 ibits,
-                          struct mdt_lock_handle *s0_lh,
-                          struct mdt_object **s0_objp,
-                          struct ldlm_enqueue_info *einfo)
+static int mdt_init_slaves(struct mdt_thread_info *mti, struct mdt_object *obj,
+                          struct lu_fid *fid)
 {
-       union ldlm_policy_data *policy = &mti->mti_policy;
        struct lu_buf *buf = &mti->mti_buf;
        struct lmv_mds_md_v1 *lmv;
-       struct lu_fid *fid = &mti->mti_tmp_fid1;
        int rc;
        ENTRY;
 
@@ -480,15 +367,46 @@ static int mdt_lock_slaves(struct mdt_thread_info *mti, struct mdt_object *obj,
                RETURN(-EINVAL);
 
        fid_le_to_cpu(fid, &lmv->lmv_stripe_fids[0]);
-       if (!lu_fid_eq(fid, mdt_object_fid(obj))) {
+
+       RETURN(rc);
+}
+
+/**
+ * Lock slave stripes if necessary, the lock handles of slave stripes
+ * will be stored in einfo->ei_cbdata.
+ **/
+static int mdt_lock_slaves(struct mdt_thread_info *mti, struct mdt_object *obj,
+                          enum ldlm_mode mode, __u64 ibits,
+                          struct lu_fid *s0_fid,
+                          struct mdt_lock_handle *s0_lh,
+                          struct mdt_object **s0_objp,
+                          struct ldlm_enqueue_info *einfo)
+{
+       union ldlm_policy_data *policy = &mti->mti_policy;
+       int rc;
+       ENTRY;
+
+       rc = mdt_init_slaves(mti, obj, s0_fid);
+       if (rc <= 0)
+               RETURN(rc);
+
+       LASSERT(S_ISDIR(obj->mot_header.loh_attr));
+
+       if (!lu_fid_eq(s0_fid, mdt_object_fid(obj))) {
                /* Except migrating object, whose 0_stripe and master
                 * object are the same object, 0_stripe and master
                 * object are different, though they are in the same
                 * MDT, to avoid adding osd_object_lock here, so we
                 * will enqueue the stripe0 lock in MDT0 for now */
-               *s0_objp = mdt_object_find_lock(mti, fid, s0_lh, ibits);
+               *s0_objp = mdt_object_find(mti->mti_env, mti->mti_mdt, s0_fid);
                if (IS_ERR(*s0_objp))
                        RETURN(PTR_ERR(*s0_objp));
+
+               rc = mdt_reint_object_lock(mti, *s0_objp, s0_lh, ibits, true);
+               if (rc < 0) {
+                       mdt_object_put(mti->mti_env, *s0_objp);
+                       RETURN(rc);
+               }
        }
 
        memset(einfo, 0, sizeof(*einfo));
@@ -507,6 +425,174 @@ static int mdt_lock_slaves(struct mdt_thread_info *mti, struct mdt_object *obj,
        RETURN(rc);
 }
 
+/*
+ * VBR: we save three versions in reply:
+ * 0 - parent. Check that parent version is the same during replay.
+ * 1 - name. Version of 'name' if file exists with the same name or
+ * ENOENT_VERSION, it is needed because file may appear due to missed replays.
+ * 2 - child. Version of child by FID. Must be ENOENT. It is mostly sanity
+ * check.
+ */
+static int mdt_md_create(struct mdt_thread_info *info)
+{
+       struct mdt_device       *mdt = info->mti_mdt;
+       struct mdt_object       *parent;
+       struct mdt_object       *child;
+       struct mdt_lock_handle  *lh;
+       struct mdt_body         *repbody;
+       struct md_attr          *ma = &info->mti_attr;
+       struct mdt_reint_record *rr = &info->mti_rr;
+       int rc;
+       ENTRY;
+
+       DEBUG_REQ(D_INODE, mdt_info_req(info), "Create  ("DNAME"->"DFID") "
+                 "in "DFID,
+                 PNAME(&rr->rr_name), PFID(rr->rr_fid2), PFID(rr->rr_fid1));
+
+       if (!fid_is_md_operative(rr->rr_fid1))
+               RETURN(-EPERM);
+
+       repbody = req_capsule_server_get(info->mti_pill, &RMF_MDT_BODY);
+
+       parent = mdt_object_find(info->mti_env, info->mti_mdt, rr->rr_fid1);
+       if (IS_ERR(parent))
+               RETURN(PTR_ERR(parent));
+
+       if (!mdt_object_exists(parent))
+               GOTO(put_parent, rc = -ENOENT);
+
+       lh = &info->mti_lh[MDT_LH_PARENT];
+       mdt_lock_pdo_init(lh, LCK_PW, &rr->rr_name);
+       rc = mdt_object_lock(info, parent, lh, MDS_INODELOCK_UPDATE);
+       if (rc)
+               GOTO(put_parent, rc);
+
+       if (!mdt_object_remote(parent)) {
+               rc = mdt_version_get_check_save(info, parent, 0);
+               if (rc)
+                       GOTO(unlock_parent, rc);
+       }
+
+       /*
+        * Check child name version during replay.
+        * During create replay a file may exist with same name.
+        */
+       rc = mdt_lookup_version_check(info, parent, &rr->rr_name,
+                                     &info->mti_tmp_fid1, 1);
+       if (rc == 0)
+               GOTO(unlock_parent, rc = -EEXIST);
+
+       /* -ENOENT is expected here */
+       if (rc != -ENOENT)
+               GOTO(unlock_parent, rc);
+
+       /* save version of file name for replay, it must be ENOENT here */
+       mdt_enoent_version_save(info, 1);
+
+       child = mdt_object_new(info->mti_env, mdt, rr->rr_fid2);
+       if (unlikely(IS_ERR(child)))
+               GOTO(unlock_parent, rc = PTR_ERR(child));
+
+       rc = mdt_remote_permission(info);
+       if (rc != 0)
+               GOTO(put_child, rc);
+
+       ma->ma_need = MA_INODE;
+       ma->ma_valid = 0;
+
+       mdt_fail_write(info->mti_env, info->mti_mdt->mdt_bottom,
+                       OBD_FAIL_MDS_REINT_CREATE_WRITE);
+
+       /* Version of child will be updated on disk. */
+       tgt_vbr_obj_set(info->mti_env, mdt_obj2dt(child));
+       rc = mdt_version_get_check_save(info, child, 2);
+       if (rc)
+               GOTO(put_child, rc);
+
+       /* Let lower layer know current lock mode. */
+       info->mti_spec.sp_cr_mode = mdt_dlm_mode2mdl_mode(lh->mlh_pdo_mode);
+
+       /*
+        * Do not perform lookup sanity check. We know that name does
+        * not exist.
+        */
+       info->mti_spec.sp_cr_lookup = 0;
+       info->mti_spec.sp_feat = &dt_directory_features;
+
+       rc = mdo_create(info->mti_env, mdt_object_child(parent), &rr->rr_name,
+                       mdt_object_child(child), &info->mti_spec, ma);
+       if (rc == 0)
+               rc = mdt_attr_get_complex(info, child, ma);
+
+       if (rc < 0)
+               GOTO(put_child, rc);
+
+       /*
+        * On DNE, we need to eliminate dependey between 'mkdir a' and
+        * 'mkdir a/b' if b is a striped directory, to achieve this, two
+        * things are done below:
+        * 1. save child and slaves lock.
+        * 2. if the child is a striped directory, relock parent so to
+        *    compare against with COS locks to ensure parent was
+        *    committed to disk.
+        */
+       if (mdt_slc_is_enabled(mdt) && S_ISDIR(ma->ma_attr.la_mode)) {
+               struct mdt_lock_handle *lhc;
+               struct mdt_lock_handle *s0_lh;
+               struct mdt_object *s0_obj = NULL;
+               struct ldlm_enqueue_info *einfo;
+               struct lu_fid *s0_fid = &info->mti_tmp_fid1;
+               bool cos_incompat = false;
+
+               rc = mdt_init_slaves(info, child, s0_fid);
+               if (rc > 0) {
+                       cos_incompat = true;
+                       if (!mdt_object_remote(parent)) {
+                               mdt_object_unlock(info, parent, lh, 1);
+                               mdt_lock_pdo_init(lh, LCK_PW, &rr->rr_name);
+                               rc = mdt_reint_object_lock(info, parent, lh,
+                                                          MDS_INODELOCK_UPDATE,
+                                                          true);
+                               if (rc)
+                                       GOTO(put_child, rc);
+                       }
+               }
+
+               einfo = &info->mti_einfo;
+               lhc = &info->mti_lh[MDT_LH_CHILD];
+               mdt_lock_handle_init(lhc);
+               mdt_lock_reg_init(lhc, LCK_PW);
+               rc = mdt_reint_object_lock(info, child, lhc,
+                                          MDS_INODELOCK_UPDATE,
+                                          cos_incompat);
+               if (rc)
+                       GOTO(put_child, rc);
+               mdt_object_unlock(info, child, lhc, rc);
+
+               s0_lh = &info->mti_lh[MDT_LH_LOCAL];
+               mdt_lock_handle_init(s0_lh);
+               mdt_lock_reg_init(s0_lh, LCK_PW);
+               rc = mdt_lock_slaves(info, child, LCK_PW, MDS_INODELOCK_UPDATE,
+                                    s0_fid, s0_lh, &s0_obj, einfo);
+               mdt_unlock_slaves(info, child, MDS_INODELOCK_UPDATE, s0_lh,
+                                 s0_obj, einfo, rc);
+               if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_SLAVE_NAME) && rc == -EIO)
+                       rc = 0;
+       }
+
+       /* Return fid & attr to client. */
+       if (ma->ma_valid & MA_INODE)
+               mdt_pack_attr2body(info, repbody, &ma->ma_attr,
+                                  mdt_object_fid(child));
+put_child:
+       mdt_object_put(info->mti_env, child);
+unlock_parent:
+       mdt_object_unlock(info, parent, lh, rc);
+put_parent:
+       mdt_object_put(info->mti_env, parent);
+       RETURN(rc);
+}
+
 static int mdt_attr_set(struct mdt_thread_info *info, struct mdt_object *mo,
                        struct md_attr *ma)
 {
@@ -514,11 +600,17 @@ static int mdt_attr_set(struct mdt_thread_info *info, struct mdt_object *mo,
        int do_vbr = ma->ma_attr.la_valid & (LA_MODE|LA_UID|LA_GID|LA_FLAGS);
        __u64 lockpart = MDS_INODELOCK_UPDATE;
        struct ldlm_enqueue_info *einfo = &info->mti_einfo;
-       struct mdt_lock_handle  *s0_lh;
-       struct mdt_object       *s0_obj = NULL;
+       struct lu_fid *s0_fid = &info->mti_tmp_fid1;
+       struct mdt_lock_handle *s0_lh = NULL;
+       struct mdt_object *s0_obj = NULL;
+       bool cos_incompat = false;
        int rc;
        ENTRY;
 
+       rc = mdt_init_slaves(info, mo, s0_fid);
+       if (rc > 0)
+               cos_incompat = true;
+
         lh = &info->mti_lh[MDT_LH_PARENT];
         mdt_lock_reg_init(lh, LCK_PW);
 
@@ -529,13 +621,14 @@ static int mdt_attr_set(struct mdt_thread_info *info, struct mdt_object *mo,
        if (ma->ma_attr.la_valid & (LA_MODE|LA_UID|LA_GID))
                lockpart |= MDS_INODELOCK_LOOKUP | MDS_INODELOCK_PERM;
 
-       rc = mdt_object_lock(info, mo, lh, lockpart);
+       rc = mdt_reint_object_lock(info, mo, lh, lockpart, cos_incompat);
        if (rc != 0)
                RETURN(rc);
 
        s0_lh = &info->mti_lh[MDT_LH_LOCAL];
        mdt_lock_reg_init(s0_lh, LCK_PW);
-       rc = mdt_lock_slaves(info, mo, LCK_PW, lockpart, s0_lh, &s0_obj, einfo);
+       rc = mdt_lock_slaves(info, mo, LCK_PW, lockpart, s0_fid, s0_lh, &s0_obj,
+                            einfo);
        if (rc != 0)
                GOTO(out_unlock, rc);
 
@@ -571,7 +664,7 @@ static int mdt_attr_set(struct mdt_thread_info *info, struct mdt_object *mo,
 
         EXIT;
 out_unlock:
-       mdt_unlock_slaves(info, mo, lockpart, s0_lh, s0_obj, einfo);
+       mdt_unlock_slaves(info, mo, lockpart, s0_lh, s0_obj, einfo, rc);
         mdt_object_unlock(info, mo, lh, rc);
         return rc;
 }
@@ -776,22 +869,24 @@ static int mdt_reint_create(struct mdt_thread_info *info,
  * Version of child is getting and checking during its lookup. If
  */
 static int mdt_reint_unlink(struct mdt_thread_info *info,
-                            struct mdt_lock_handle *lhc)
+                           struct mdt_lock_handle *lhc)
 {
-        struct mdt_reint_record *rr = &info->mti_rr;
-        struct ptlrpc_request   *req = mdt_info_req(info);
-        struct md_attr          *ma = &info->mti_attr;
-        struct lu_fid           *child_fid = &info->mti_tmp_fid1;
-        struct mdt_object       *mp;
-        struct mdt_object       *mc;
-        struct mdt_lock_handle  *parent_lh;
-        struct mdt_lock_handle  *child_lh;
+       struct mdt_reint_record *rr = &info->mti_rr;
+       struct ptlrpc_request *req = mdt_info_req(info);
+       struct md_attr *ma = &info->mti_attr;
+       struct lu_fid *child_fid = &info->mti_tmp_fid1;
+       struct mdt_object *mp;
+       struct mdt_object *mc;
+       struct mdt_lock_handle *parent_lh;
+       struct mdt_lock_handle *child_lh;
        struct ldlm_enqueue_info *einfo = &info->mti_einfo;
-       struct mdt_lock_handle  *s0_lh = NULL;
-       struct mdt_object       *s0_obj = NULL;
-       __u64                   lock_ibits;
-       int                     rc;
-       int                     no_name = 0;
+       struct lu_fid *s0_fid = &info->mti_tmp_fid2;
+       struct mdt_lock_handle *s0_lh = NULL;
+       struct mdt_object *s0_obj = NULL;
+       __u64 lock_ibits;
+       bool cos_incompat = false;
+       int no_name = 0;
+       int rc;
        ENTRY;
 
        DEBUG_REQ(D_INODE, req, "unlink "DFID"/"DNAME"", PFID(rr->rr_fid1),
@@ -800,34 +895,22 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
        if (info->mti_dlm_req)
                ldlm_request_cancel(req, info->mti_dlm_req, 0, LATF_SKIP);
 
-        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_REINT_UNLINK))
-                RETURN(err_serious(-ENOENT));
+       if (OBD_FAIL_CHECK(OBD_FAIL_MDS_REINT_UNLINK))
+               RETURN(err_serious(-ENOENT));
 
        if (!fid_is_md_operative(rr->rr_fid1))
                RETURN(-EPERM);
 
-        /*
-        * step 1: Found the parent.
-         */
        mp = mdt_object_find(info->mti_env, info->mti_mdt, rr->rr_fid1);
-       if (IS_ERR(mp)) {
-               rc = PTR_ERR(mp);
-               GOTO(out, rc);
-       }
-
-       parent_lh = &info->mti_lh[MDT_LH_PARENT];
-       mdt_lock_pdo_init(parent_lh, LCK_PW, &rr->rr_name);
-       rc = mdt_object_lock(info, mp, parent_lh, MDS_INODELOCK_UPDATE);
-       if (rc != 0)
-               GOTO(put_parent, rc);
+       if (IS_ERR(mp))
+               RETURN(PTR_ERR(mp));
 
        if (!mdt_object_remote(mp)) {
                rc = mdt_version_get_check_save(info, mp, 0);
                if (rc)
-                       GOTO(unlock_parent, rc);
+                       GOTO(put_parent, rc);
        }
 
-       /* step 2: find & lock the child */
        /* lookup child object along with version checking */
        fid_zero(child_fid);
        rc = mdt_lookup_version_check(info, mp, &rr->rr_name, child_fid, 1);
@@ -852,35 +935,45 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
                        no_name = 1;
                        *child_fid = *rr->rr_fid2;
                 } else {
-                       GOTO(unlock_parent, rc);
+                       GOTO(put_parent, rc);
                 }
        }
 
        if (!fid_is_md_operative(child_fid))
-               GOTO(unlock_parent, rc = -EPERM);
+               GOTO(put_parent, rc = -EPERM);
 
        /* We will lock the child regardless it is local or remote. No harm. */
        mc = mdt_object_find(info->mti_env, info->mti_mdt, child_fid);
        if (IS_ERR(mc))
-               GOTO(unlock_parent, rc = PTR_ERR(mc));
+               GOTO(put_parent, rc = PTR_ERR(mc));
+
+       rc = mdt_init_slaves(info, mc, s0_fid);
+       cos_incompat = (mdt_object_remote(mp) || (rc > 0));
+
+       parent_lh = &info->mti_lh[MDT_LH_PARENT];
+       mdt_lock_pdo_init(parent_lh, LCK_PW, &rr->rr_name);
+       rc = mdt_reint_object_lock(info, mp, parent_lh, MDS_INODELOCK_UPDATE,
+                                  cos_incompat);
+       if (rc != 0)
+               GOTO(put_child, rc);
 
-        child_lh = &info->mti_lh[MDT_LH_CHILD];
-        mdt_lock_reg_init(child_lh, LCK_EX);
+       child_lh = &info->mti_lh[MDT_LH_CHILD];
+       mdt_lock_reg_init(child_lh, LCK_EX);
        if (info->mti_spec.sp_rm_entry) {
                struct lu_ucred *uc  = mdt_ucred(info);
 
                if (!mdt_is_dne_client(req->rq_export))
                        /* Return -ENOTSUPP for old client */
-                       GOTO(put_child, rc = -ENOTSUPP);
+                       GOTO(unlock_parent, rc = -ENOTSUPP);
 
                if (!md_capable(uc, CFS_CAP_SYS_ADMIN))
-                       GOTO(put_child, rc = -EPERM);
+                       GOTO(unlock_parent, rc = -EPERM);
 
                ma->ma_need = MA_INODE;
                ma->ma_valid = 0;
                rc = mdo_unlink(info->mti_env, mdt_object_child(mp),
                                NULL, &rr->rr_name, ma, no_name);
-               GOTO(put_child, rc);
+               GOTO(unlock_parent, rc);
        }
 
        if (mdt_object_remote(mc)) {
@@ -890,7 +983,7 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
                        CDEBUG(D_INFO, "%s: name "DNAME" cannot find "DFID"\n",
                               mdt_obd_name(info->mti_mdt),
                               PNAME(&rr->rr_name), PFID(mdt_object_fid(mc)));
-                       GOTO(put_child, rc = -ENOENT);
+                       GOTO(unlock_parent, rc = -ENOENT);
                }
                CDEBUG(D_INFO, "%s: name "DNAME": "DFID" is on another MDT\n",
                       mdt_obd_name(info->mti_mdt),
@@ -898,7 +991,7 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
 
                if (!mdt_is_dne_client(req->rq_export))
                        /* Return -ENOTSUPP for old client */
-                       GOTO(put_child, rc = -ENOTSUPP);
+                       GOTO(unlock_parent, rc = -ENOTSUPP);
 
                /* Revoke the LOOKUP lock of the remote object granted by
                 * this MDT. Since the unlink will happen on another MDT,
@@ -923,14 +1016,16 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
                                            child_lh->mlh_rreg_mode,
                                            MDS_INODELOCK_LOOKUP, false);
                if (rc != ELDLM_OK)
-                       GOTO(put_child, rc);
+                       GOTO(unlock_parent, rc);
 
                lock_ibits &= ~MDS_INODELOCK_LOOKUP;
        }
 
-       rc = mdt_object_lock(info, mc, child_lh, lock_ibits);
+       rc = mdt_reint_object_lock(info, mc, child_lh, lock_ibits,
+                                  cos_incompat);
        if (rc != 0)
-               GOTO(put_child, rc);
+               GOTO(unlock_child, rc);
+
        /*
         * Now we can only make sure we need MA_INODE, in mdd layer, will check
         * whether need MA_LOV and MA_COOKIE.
@@ -940,8 +1035,8 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
 
        s0_lh = &info->mti_lh[MDT_LH_LOCAL];
        mdt_lock_reg_init(s0_lh, LCK_EX);
-       rc = mdt_lock_slaves(info, mc, LCK_EX, MDS_INODELOCK_UPDATE, s0_lh,
-                            &s0_obj, einfo);
+       rc = mdt_lock_slaves(info, mc, LCK_EX, MDS_INODELOCK_UPDATE, s0_fid,
+                            s0_lh, &s0_obj, einfo);
        if (rc != 0)
                GOTO(unlock_child, rc);
 
@@ -984,15 +1079,15 @@ static int mdt_reint_unlink(struct mdt_thread_info *info,
         EXIT;
 
 unlock_child:
-       mdt_unlock_slaves(info, mc, MDS_INODELOCK_UPDATE, s0_lh, s0_obj, einfo);
+       mdt_unlock_slaves(info, mc, MDS_INODELOCK_UPDATE, s0_lh, s0_obj, einfo,
+                         rc);
        mdt_object_unlock(info, mc, child_lh, rc);
-put_child:
-       mdt_object_put(info->mti_env, mc);
 unlock_parent:
        mdt_object_unlock(info, mp, parent_lh, rc);
+put_child:
+       mdt_object_put(info->mti_env, mc);
 put_parent:
        mdt_object_put(info->mti_env, mp);
-out:
         return rc;
 }
 
@@ -1001,109 +1096,117 @@ out:
  * name.
  */
 static int mdt_reint_link(struct mdt_thread_info *info,
-                          struct mdt_lock_handle *lhc)
+                         struct mdt_lock_handle *lhc)
 {
-        struct mdt_reint_record *rr = &info->mti_rr;
-        struct ptlrpc_request   *req = mdt_info_req(info);
-        struct md_attr          *ma = &info->mti_attr;
-        struct mdt_object       *ms;
-        struct mdt_object       *mp;
-        struct mdt_lock_handle  *lhs;
-        struct mdt_lock_handle  *lhp;
-        int rc;
-        ENTRY;
+       struct mdt_reint_record *rr = &info->mti_rr;
+       struct ptlrpc_request   *req = mdt_info_req(info);
+       struct md_attr          *ma = &info->mti_attr;
+       struct mdt_object       *ms;
+       struct mdt_object       *mp;
+       struct mdt_lock_handle  *lhs;
+       struct mdt_lock_handle  *lhp;
+       bool cos_incompat;
+       int rc;
+       ENTRY;
 
        DEBUG_REQ(D_INODE, req, "link "DFID" to "DFID"/"DNAME,
                  PFID(rr->rr_fid1), PFID(rr->rr_fid2), PNAME(&rr->rr_name));
 
-        if (OBD_FAIL_CHECK(OBD_FAIL_MDS_REINT_LINK))
-                RETURN(err_serious(-ENOENT));
+       if (OBD_FAIL_CHECK(OBD_FAIL_MDS_REINT_LINK))
+               RETURN(err_serious(-ENOENT));
 
        if (info->mti_dlm_req)
                ldlm_request_cancel(req, info->mti_dlm_req, 0, LATF_SKIP);
 
-        /* Invalid case so return error immediately instead of
-         * processing it */
-        if (lu_fid_eq(rr->rr_fid1, rr->rr_fid2))
-                RETURN(-EPERM);
+       /* Invalid case so return error immediately instead of
+        * processing it */
+       if (lu_fid_eq(rr->rr_fid1, rr->rr_fid2))
+               RETURN(-EPERM);
 
        if (!fid_is_md_operative(rr->rr_fid1) ||
            !fid_is_md_operative(rr->rr_fid2))
                RETURN(-EPERM);
 
-        /* step 1: find & lock the target parent dir */
-        lhp = &info->mti_lh[MDT_LH_PARENT];
-       mdt_lock_pdo_init(lhp, LCK_PW, &rr->rr_name);
-        mp = mdt_object_find_lock(info, rr->rr_fid2, lhp,
-                                  MDS_INODELOCK_UPDATE);
-        if (IS_ERR(mp))
-                RETURN(PTR_ERR(mp));
-
-        rc = mdt_version_get_check_save(info, mp, 0);
-        if (rc)
-                GOTO(out_unlock_parent, rc);
-
-       OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME3, 5);
+       /* step 1: find target parent dir */
+       mp = mdt_object_find(info->mti_env, info->mti_mdt, rr->rr_fid2);
+       if (IS_ERR(mp))
+               RETURN(PTR_ERR(mp));
 
-        /* step 2: find & lock the source */
-        lhs = &info->mti_lh[MDT_LH_CHILD];
-        mdt_lock_reg_init(lhs, LCK_EX);
+       rc = mdt_version_get_check_save(info, mp, 0);
+       if (rc)
+               GOTO(put_parent, rc);
 
-        ms = mdt_object_find(info->mti_env, info->mti_mdt, rr->rr_fid1);
-        if (IS_ERR(ms))
-                GOTO(out_unlock_parent, rc = PTR_ERR(ms));
+       /* step 2: find source */
+       ms = mdt_object_find(info->mti_env, info->mti_mdt, rr->rr_fid1);
+       if (IS_ERR(ms))
+               GOTO(put_parent, rc = PTR_ERR(ms));
 
        if (!mdt_object_exists(ms)) {
-               mdt_object_put(info->mti_env, ms);
                CDEBUG(D_INFO, "%s: "DFID" does not exist.\n",
                       mdt_obd_name(info->mti_mdt), PFID(rr->rr_fid1));
-               GOTO(out_unlock_parent, rc = -ENOENT);
+               GOTO(put_source, rc = -ENOENT);
        }
 
-       rc = mdt_object_lock(info, ms, lhs, MDS_INODELOCK_UPDATE |
-                            MDS_INODELOCK_XATTR);
-        if (rc != 0) {
-                mdt_object_put(info->mti_env, ms);
-                GOTO(out_unlock_parent, rc);
-        }
+       cos_incompat = (mdt_object_remote(mp) || mdt_object_remote(ms));
 
-        /* step 3: link it */
-        mdt_fail_write(info->mti_env, info->mti_mdt->mdt_bottom,
-                       OBD_FAIL_MDS_REINT_LINK_WRITE);
+       lhp = &info->mti_lh[MDT_LH_PARENT];
+       mdt_lock_pdo_init(lhp, LCK_PW, &rr->rr_name);
+       rc = mdt_reint_object_lock(info, mp, lhp, MDS_INODELOCK_UPDATE,
+                                  cos_incompat);
+       if (rc != 0)
+               GOTO(put_source, rc);
+
+       OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME3, 5);
+
+       lhs = &info->mti_lh[MDT_LH_CHILD];
+       mdt_lock_reg_init(lhs, LCK_EX);
+       rc = mdt_reint_object_lock(info, ms, lhs,
+                                  MDS_INODELOCK_UPDATE | MDS_INODELOCK_XATTR,
+                                  cos_incompat);
+       if (rc != 0)
+               GOTO(unlock_parent, rc);
+
+       /* step 3: link it */
+       mdt_fail_write(info->mti_env, info->mti_mdt->mdt_bottom,
+                       OBD_FAIL_MDS_REINT_LINK_WRITE);
 
        tgt_vbr_obj_set(info->mti_env, mdt_obj2dt(ms));
-        rc = mdt_version_get_check_save(info, ms, 1);
-        if (rc)
-                GOTO(out_unlock_child, rc);
+       rc = mdt_version_get_check_save(info, ms, 1);
+       if (rc)
+               GOTO(unlock_source, rc);
 
-        /** check target version by name during replay */
+       /** check target version by name during replay */
        rc = mdt_lookup_version_check(info, mp, &rr->rr_name,
                                      &info->mti_tmp_fid1, 2);
-        if (rc != 0 && rc != -ENOENT)
-                GOTO(out_unlock_child, rc);
-        /* save version of file name for replay, it must be ENOENT here */
-        if (!req_is_replay(mdt_info_req(info))) {
+       if (rc != 0 && rc != -ENOENT)
+               GOTO(unlock_source, rc);
+       /* save version of file name for replay, it must be ENOENT here */
+       if (!req_is_replay(mdt_info_req(info))) {
                if (rc != -ENOENT) {
                        CDEBUG(D_INFO, "link target "DNAME" existed!\n",
                               PNAME(&rr->rr_name));
-                       GOTO(out_unlock_child, rc = -EEXIST);
+                       GOTO(unlock_source, rc = -EEXIST);
                }
-                info->mti_ver[2] = ENOENT_VERSION;
-                mdt_version_save(mdt_info_req(info), info->mti_ver[2], 2);
-        }
+               info->mti_ver[2] = ENOENT_VERSION;
+               mdt_version_save(mdt_info_req(info), info->mti_ver[2], 2);
+       }
 
        rc = mdo_link(info->mti_env, mdt_object_child(mp),
-             mdt_object_child(ms), &rr->rr_name, ma);
+                     mdt_object_child(ms), &rr->rr_name, ma);
 
-        if (rc == 0)
+       if (rc == 0)
                mdt_counter_incr(req, LPROC_MDT_LINK);
 
-        EXIT;
-out_unlock_child:
-        mdt_object_unlock_put(info, ms, lhs, rc);
-out_unlock_parent:
-        mdt_object_unlock_put(info, mp, lhp, rc);
-        return rc;
+       EXIT;
+unlock_source:
+       mdt_object_unlock(info, ms, lhs, rc);
+unlock_parent:
+       mdt_object_unlock(info, mp, lhp, rc);
+put_source:
+       mdt_object_put(info->mti_env, ms);
+put_parent:
+       mdt_object_put(info->mti_env, mp);
+       return rc;
 }
 /**
  * lock the part of the directory according to the hash of the name
@@ -1111,11 +1214,13 @@ out_unlock_parent:
  */
 static int mdt_pdir_hash_lock(struct mdt_thread_info *info,
                              struct mdt_lock_handle *lh,
-                             struct mdt_object *obj, __u64 ibits)
+                             struct mdt_object *obj, __u64 ibits,
+                             bool cos_incompat)
 {
        struct ldlm_res_id *res = &info->mti_res_id;
        struct ldlm_namespace *ns = info->mti_mdt->mdt_namespace;
        union ldlm_policy_data *policy = &info->mti_policy;
+       __u64 dlmflags = LDLM_FL_LOCAL_ONLY | LDLM_FL_ATOMIC_CB;
        int rc;
 
        /*
@@ -1126,14 +1231,16 @@ static int mdt_pdir_hash_lock(struct mdt_thread_info *info,
        fid_build_pdo_res_name(mdt_object_fid(obj), lh->mlh_pdo_hash, res);
        memset(policy, 0, sizeof(*policy));
        policy->l_inodebits.bits = ibits;
+       if (cos_incompat &&
+           (lh->mlh_reg_mode == LCK_PW || lh->mlh_reg_mode == LCK_EX))
+               dlmflags |= LDLM_FL_COS_INCOMPAT;
        /*
         * 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, LDLM_FL_LOCAL_ONLY | LDLM_FL_ATOMIC_CB,
-                         &info->mti_exp->exp_handle.h_cookie);
+                         res, dlmflags, &info->mti_exp->exp_handle.h_cookie);
        return rc;
 }
 
@@ -1335,8 +1442,8 @@ again:
                 * cannot be gotten because of conflicting locks, then drop all
                 * current locks, send an AST to the client, and start again. */
                mdt_lock_pdo_init(&mll->mll_lh, LCK_PW, &name);
-               rc = mdt_object_lock_try(info, mdt_pobj, &mll->mll_lh,
-                                        MDS_INODELOCK_UPDATE);
+               rc = mdt_reint_object_lock_try(info, mdt_pobj, &mll->mll_lh,
+                                               MDS_INODELOCK_UPDATE, true);
                if (rc == 0) {
                        mdt_unlock_list(info, lock_list, rc);
 
@@ -1426,8 +1533,8 @@ static int mdt_reint_migrate_internal(struct mdt_thread_info *info,
 
        lh_dirp = &info->mti_lh[MDT_LH_PARENT];
        mdt_lock_pdo_init(lh_dirp, LCK_PW, &rr->rr_name);
-       rc = mdt_object_lock(info, msrcdir, lh_dirp,
-                            MDS_INODELOCK_UPDATE);
+       rc = mdt_reint_object_lock(info, msrcdir, lh_dirp, MDS_INODELOCK_UPDATE,
+                                  true);
        if (rc)
                GOTO(out_put_parent, rc);
 
@@ -1547,7 +1654,7 @@ out_lease:
                lock_ibits &= ~MDS_INODELOCK_LOOKUP;
        }
 
-       rc = mdt_object_lock(info, mold, lh_childp, lock_ibits);
+       rc = mdt_reint_object_lock(info, mold, lh_childp, lock_ibits, true);
        if (rc != 0)
                GOTO(out_unlock_child, rc);
 
@@ -1645,7 +1752,10 @@ out_put_new:
 out_unlock_child:
        mdt_object_unlock(info, mold, lh_childp, rc);
 out_unlock_list:
-       mdt_unlock_list(info, &lock_list, rc);
+       /* we don't really modify linkea objects, so we can safely decref these
+        * locks, and this can avoid saving them as COS locks, which may prevent
+        * subsequent migrate. */
+       mdt_unlock_list(info, &lock_list, 1);
        if (lease != NULL) {
                ldlm_reprocess_all(lease->l_resource);
                LDLM_LOCK_PUT(lease);
@@ -1689,12 +1799,13 @@ out_put:
 static int mdt_object_lock_save(struct mdt_thread_info *info,
                                struct mdt_object *dir,
                                struct mdt_lock_handle *lh,
-                               int idx)
+                               int idx, bool cos_incompat)
 {
        int rc;
 
        /* we lock the target dir if it is local */
-       rc = mdt_object_lock(info, dir, lh, MDS_INODELOCK_UPDATE);
+       rc = mdt_reint_object_lock(info, dir, lh, MDS_INODELOCK_UPDATE,
+                                  cos_incompat);
        if (rc != 0)
                return rc;
 
@@ -1703,146 +1814,125 @@ static int mdt_object_lock_save(struct mdt_thread_info *info,
        return 0;
 }
 
-
-static int mdt_rename_parents_lock(struct mdt_thread_info *info,
-                                  struct mdt_object **srcp,
-                                  struct mdt_object **tgtp)
+/*
+ * VBR: rename versions in reply: 0 - srcdir parent; 1 - tgtdir parent;
+ * 2 - srcdir child; 3 - tgtdir child.
+ * Update on disk version of srcdir child.
+ */
+/**
+ * For DNE phase I, only these renames are allowed
+ *     mv src_p/src_c tgt_p/tgt_c
+ * 1. src_p/src_c/tgt_p/tgt_c are in the same MDT.
+ * 2. src_p and tgt_p are same directory, and tgt_c does not
+ *    exists. In this case, all of modification will happen
+ *    in the MDT where ithesource parent is, only one remote
+ *    update is needed, i.e. set c_time/m_time on the child.
+ *    And tgt_c will be still in the same MDT as the original
+ *    src_c.
+ */
+static int mdt_reint_rename_internal(struct mdt_thread_info *info,
+                                    struct mdt_lock_handle *lhc)
 {
        struct mdt_reint_record *rr = &info->mti_rr;
-       const struct lu_fid     *fid_src = rr->rr_fid1;
-       const struct lu_fid     *fid_tgt = rr->rr_fid2;
-       struct mdt_lock_handle  *lh_src = &info->mti_lh[MDT_LH_PARENT];
-       struct mdt_lock_handle  *lh_tgt = &info->mti_lh[MDT_LH_CHILD];
-       struct mdt_object       *src;
-       struct mdt_object       *tgt;
-       int                      reverse = 0;
-       int                      rc;
+       struct md_attr *ma = &info->mti_attr;
+       struct ptlrpc_request *req = mdt_info_req(info);
+       struct mdt_object *msrcdir = NULL;
+       struct mdt_object *mtgtdir = NULL;
+       struct mdt_object *mold;
+       struct mdt_object *mnew = NULL;
+       struct mdt_lock_handle *lh_srcdirp;
+       struct mdt_lock_handle *lh_tgtdirp;
+       struct mdt_lock_handle *lh_oldp = NULL;
+       struct mdt_lock_handle *lh_newp = NULL;
+       struct lu_fid *old_fid = &info->mti_tmp_fid1;
+       struct lu_fid *new_fid = &info->mti_tmp_fid2;
+       __u64 lock_ibits;
+       bool reverse = false;
+       bool cos_incompat;
+       int rc;
        ENTRY;
 
+       DEBUG_REQ(D_INODE, req, "rename "DFID"/"DNAME" to "DFID"/"DNAME,
+                 PFID(rr->rr_fid1), PNAME(&rr->rr_name),
+                 PFID(rr->rr_fid2), PNAME(&rr->rr_tgt_name));
+
        /* find both parents. */
-       src = mdt_object_find_check(info, fid_src, 0);
-       if (IS_ERR(src))
-               RETURN(PTR_ERR(src));
+       msrcdir = mdt_object_find_check(info, rr->rr_fid1, 0);
+       if (IS_ERR(msrcdir))
+               RETURN(PTR_ERR(msrcdir));
 
        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME3, 5);
 
-       if (lu_fid_eq(fid_src, fid_tgt)) {
-               tgt = src;
-               mdt_object_get(info->mti_env, tgt);
+       if (lu_fid_eq(rr->rr_fid1, rr->rr_fid2)) {
+               mtgtdir = msrcdir;
+               mdt_object_get(info->mti_env, mtgtdir);
        } else {
-               /* Check if the @src is not a child of the @tgt, otherwise a
-                * reverse locking must take place. */
-               rc = mdt_is_subdir(info, src, fid_tgt);
+               /* Check if the @msrcdir is not a child of the @mtgtdir,
+                * otherwise a reverse locking must take place. */
+               rc = mdt_is_subdir(info, msrcdir, rr->rr_fid2);
                if (rc == -EINVAL)
-                       reverse = 1;
+                       reverse = true;
                else if (rc)
-                       GOTO(err_src_put, rc);
+                       GOTO(out_put_srcdir, rc);
 
-               tgt = mdt_object_find_check(info, fid_tgt, 1);
-               if (IS_ERR(tgt))
-                       GOTO(err_src_put, rc = PTR_ERR(tgt));
+               mtgtdir = mdt_object_find_check(info, rr->rr_fid2, 1);
+               if (IS_ERR(mtgtdir))
+                       GOTO(out_put_srcdir, rc = PTR_ERR(mtgtdir));
        }
 
+       /* source needs to be looked up after locking source parent, otherwise
+        * this rename may race with unlink source, and cause rename hang, see
+        * sanityn.sh 55b, so check parents first, if later we found source is
+        * remote, relock parents. */
+       cos_incompat = (mdt_object_remote(msrcdir) ||
+                       mdt_object_remote(mtgtdir));
+
        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME4, 5);
 
        /* lock parents in the proper order. */
+       lh_srcdirp = &info->mti_lh[MDT_LH_PARENT];
+       lh_tgtdirp = &info->mti_lh[MDT_LH_CHILD];
+
+relock:
+       mdt_lock_pdo_init(lh_srcdirp, LCK_PW, &rr->rr_name);
+       mdt_lock_pdo_init(lh_tgtdirp, LCK_PW, &rr->rr_tgt_name);
+
        if (reverse) {
-               rc = mdt_object_lock_save(info, tgt, lh_tgt, 1);
+               rc = mdt_object_lock_save(info, mtgtdir, lh_tgtdirp, 1,
+                                         cos_incompat);
                if (rc)
-                       GOTO(err_tgt_put, rc);
+                       GOTO(out_put_tgtdir, rc);
 
                OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME, 5);
 
-               rc = mdt_object_lock_save(info, src, lh_src, 0);
+               rc = mdt_object_lock_save(info, msrcdir, lh_srcdirp, 0,
+                                         cos_incompat);
        } else {
-               rc = mdt_object_lock_save(info, src, lh_src, 0);
+               rc = mdt_object_lock_save(info, msrcdir, lh_srcdirp, 0,
+                                         cos_incompat);
                if (rc)
-                       GOTO(err_tgt_put, rc);
+                       GOTO(out_put_tgtdir, rc);
 
                OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME, 5);
 
-               if (tgt != src)
-                       rc = mdt_object_lock_save(info, tgt, lh_tgt, 1);
-               else if (lh_src->mlh_pdo_hash != lh_tgt->mlh_pdo_hash) {
-                       rc = mdt_pdir_hash_lock(info, lh_tgt, tgt,
-                                               MDS_INODELOCK_UPDATE);
+               if (mtgtdir != msrcdir) {
+                       rc = mdt_object_lock_save(info, mtgtdir, lh_tgtdirp, 1,
+                                                 cos_incompat);
+               } else if (lh_srcdirp->mlh_pdo_hash !=
+                          lh_tgtdirp->mlh_pdo_hash) {
+                       rc = mdt_pdir_hash_lock(info, lh_tgtdirp, mtgtdir,
+                                               MDS_INODELOCK_UPDATE,
+                                               cos_incompat);
                        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_PDO_LOCK2, 10);
                }
        }
        if (rc)
-               GOTO(err_unlock, rc);
+               GOTO(out_unlock_parents, rc);
 
        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME4, 5);
-
-       *srcp = src;
-       *tgtp = tgt;
-       RETURN(0);
-
-err_unlock:
-       /* The order does not matter as the handle is checked inside,
-        * as well as not used handle. */
-       mdt_object_unlock(info, src, lh_src, rc);
-       mdt_object_unlock(info, tgt, lh_tgt, rc);
-err_tgt_put:
-       mdt_object_put(info->mti_env, tgt);
-err_src_put:
-       mdt_object_put(info->mti_env, src);
-       RETURN(rc);
-}
-
-/*
- * VBR: rename versions in reply: 0 - src parent; 1 - tgt parent;
- * 2 - src child; 3 - tgt child.
- * Update on disk version of src child.
- */
-/**
- * For DNE phase I, only these renames are allowed
- *     mv src_p/src_c tgt_p/tgt_c
- * 1. src_p/src_c/tgt_p/tgt_c are in the same MDT.
- * 2. src_p and tgt_p are same directory, and tgt_c does not
- *    exists. In this case, all of modification will happen
- *    in the MDT where ithesource parent is, only one remote
- *    update is needed, i.e. set c_time/m_time on the child.
- *    And tgt_c will be still in the same MDT as the original
- *    src_c.
- */
-static int mdt_reint_rename_internal(struct mdt_thread_info *info,
-                                    struct mdt_lock_handle *lhc)
-{
-       struct mdt_reint_record *rr = &info->mti_rr;
-       struct md_attr          *ma = &info->mti_attr;
-       struct ptlrpc_request   *req = mdt_info_req(info);
-       struct mdt_object       *msrcdir = NULL;
-       struct mdt_object       *mtgtdir = NULL;
-       struct mdt_object       *mold;
-       struct mdt_object       *mnew = NULL;
-       struct mdt_lock_handle  *lh_srcdirp;
-       struct mdt_lock_handle  *lh_tgtdirp;
-       struct mdt_lock_handle  *lh_oldp = NULL;
-       struct mdt_lock_handle  *lh_newp = NULL;
-       struct lu_fid           *old_fid = &info->mti_tmp_fid1;
-       struct lu_fid           *new_fid = &info->mti_tmp_fid2;
-       __u64                   lock_ibits;
-       int                      rc;
-       ENTRY;
-
-       DEBUG_REQ(D_INODE, req, "rename "DFID"/"DNAME" to "DFID"/"DNAME,
-                 PFID(rr->rr_fid1), PNAME(&rr->rr_name),
-                 PFID(rr->rr_fid2), PNAME(&rr->rr_tgt_name));
-
-       lh_srcdirp = &info->mti_lh[MDT_LH_PARENT];
-       mdt_lock_pdo_init(lh_srcdirp, LCK_PW, &rr->rr_name);
-       lh_tgtdirp = &info->mti_lh[MDT_LH_CHILD];
-       mdt_lock_pdo_init(lh_tgtdirp, LCK_PW, &rr->rr_tgt_name);
-
-       /* step 1&2: lock the source and target dirs. */
-       rc = mdt_rename_parents_lock(info, &msrcdir, &mtgtdir);
-       if (rc)
-               RETURN(rc);
-
        OBD_FAIL_TIMEOUT(OBD_FAIL_MDS_RENAME2, 5);
 
-       /* step 3: find & lock the old object. */
+       /* find mold object. */
        fid_zero(old_fid);
        rc = mdt_lookup_version_check(info, msrcdir, &rr->rr_name, old_fid, 2);
        if (rc != 0)
@@ -1868,9 +1958,17 @@ static int mdt_reint_rename_internal(struct mdt_thread_info *info,
        /* save version after locking */
        mdt_version_get_save(info, mold, 2);
 
-       /* step 4: find & lock the new object. */
-       /* new target object may not exist now */
-       /* lookup with version checking */
+       if (!cos_incompat && mdt_object_remote(mold)) {
+               cos_incompat = true;
+               mdt_object_put(info->mti_env, mold);
+               mdt_object_unlock(info, mtgtdir, lh_tgtdirp, -EAGAIN);
+               mdt_object_unlock(info, msrcdir, lh_srcdirp, -EAGAIN);
+               goto relock;
+       }
+
+       /* find mnew object:
+        * mnew target object may not exist now
+        * lookup with version checking */
        fid_zero(new_fid);
        rc = mdt_lookup_version_check(info, mtgtdir, &rr->rr_tgt_name, new_fid,
                                      3);
@@ -1911,7 +2009,6 @@ static int mdt_reint_rename_internal(struct mdt_thread_info *info,
 
                lh_oldp = &info->mti_lh[MDT_LH_OLD];
                mdt_lock_reg_init(lh_oldp, LCK_EX);
-
                lock_ibits = MDS_INODELOCK_LOOKUP | MDS_INODELOCK_XATTR;
                if (mdt_object_remote(msrcdir)) {
                        /* Enqueue lookup lock from the parent MDT */
@@ -1927,7 +2024,8 @@ static int mdt_reint_rename_internal(struct mdt_thread_info *info,
                        lock_ibits &= ~MDS_INODELOCK_LOOKUP;
                }
 
-               rc = mdt_object_lock(info, mold, lh_oldp, lock_ibits);
+               rc = mdt_reint_object_lock(info, mold, lh_oldp, lock_ibits,
+                                          cos_incompat);
                if (rc != 0)
                        GOTO(out_unlock_old, rc);
 
@@ -1944,9 +2042,10 @@ static int mdt_reint_rename_internal(struct mdt_thread_info *info,
 
                lh_newp = &info->mti_lh[MDT_LH_NEW];
                mdt_lock_reg_init(lh_newp, LCK_EX);
-               rc = mdt_object_lock(info, mnew, lh_newp,
-                                    MDS_INODELOCK_LOOKUP |
-                                    MDS_INODELOCK_UPDATE);
+               rc = mdt_reint_object_lock(info, mnew, lh_newp,
+                                          MDS_INODELOCK_LOOKUP |
+                                          MDS_INODELOCK_UPDATE,
+                                          cos_incompat);
                if (rc != 0)
                        GOTO(out_unlock_old, rc);
 
@@ -1957,7 +2056,6 @@ static int mdt_reint_rename_internal(struct mdt_thread_info *info,
        } else {
                lh_oldp = &info->mti_lh[MDT_LH_OLD];
                mdt_lock_reg_init(lh_oldp, LCK_EX);
-
                lock_ibits = MDS_INODELOCK_LOOKUP | MDS_INODELOCK_XATTR;
                if (mdt_object_remote(msrcdir)) {
                        /* Enqueue lookup lock from the parent MDT */
@@ -1968,14 +2066,15 @@ static int mdt_reint_rename_internal(struct mdt_thread_info *info,
                                                    MDS_INODELOCK_LOOKUP,
                                                    false);
                        if (rc != ELDLM_OK)
-                               GOTO(out_put_new, rc);
+                               GOTO(out_put_old, rc);
 
                        lock_ibits &= ~MDS_INODELOCK_LOOKUP;
                }
 
-               rc = mdt_object_lock(info, mold, lh_oldp, lock_ibits);
+               rc = mdt_reint_object_lock(info, mold, lh_oldp, lock_ibits,
+                                          cos_incompat);
                if (rc != 0)
-                       GOTO(out_put_old, rc);
+                       GOTO(out_unlock_old, rc);
 
                mdt_enoent_version_save(info, 3);
        }
@@ -2018,8 +2117,12 @@ out_put_new:
 out_put_old:
        mdt_object_put(info->mti_env, mold);
 out_unlock_parents:
-       mdt_object_unlock_put(info, mtgtdir, lh_tgtdirp, rc);
-       mdt_object_unlock_put(info, msrcdir, lh_srcdirp, rc);
+       mdt_object_unlock(info, mtgtdir, lh_tgtdirp, rc);
+       mdt_object_unlock(info, msrcdir, lh_srcdirp, rc);
+out_put_tgtdir:
+       mdt_object_put(info->mti_env, mtgtdir);
+out_put_srcdir:
+       mdt_object_put(info->mti_env, msrcdir);
        return rc;
 }