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LU-4704 test: enable acl 974 and 2561 series test
[fs/lustre-release.git] / lustre / lfsck / lfsck_layout.c
index f77ee87..45247f2 100644 (file)
@@ -652,6 +652,15 @@ out:
        }
 }
 
+static inline bool is_dummy_lov_ost_data(struct lov_ost_data_v1 *obj)
+{
+       if (fid_is_zero(&obj->l_ost_oi.oi_fid) &&
+           obj->l_ost_gen == 0 && obj->l_ost_idx == 0)
+               return true;
+
+       return false;
+}
+
 static void lfsck_layout_le_to_cpu(struct lfsck_layout *des,
                                   const struct lfsck_layout *src)
 {
@@ -771,7 +780,8 @@ static int lfsck_layout_store(const struct lu_env *env,
                RETURN(rc);
        }
 
-       rc = dt_declare_record_write(env, obj, size, pos, handle);
+       rc = dt_declare_record_write(env, obj, lfsck_buf_get(env, lo, size),
+                                    pos, handle);
        if (rc != 0) {
                CERROR("%s: fail to declare trans for storing lfsck_layout(1): "
                       "rc = %d\n", lfsck_lfsck2name(lfsck), rc);
@@ -913,7 +923,10 @@ lfsck_layout_lastid_create(const struct lu_env *env,
        if (rc != 0)
                GOTO(stop, rc);
 
-       rc = dt_declare_record_write(env, obj, sizeof(lastid), pos, th);
+       rc = dt_declare_record_write(env, obj,
+                                    lfsck_buf_get(env, &lastid,
+                                                  sizeof(lastid)),
+                                    pos, th);
        if (rc != 0)
                GOTO(stop, rc);
 
@@ -1033,8 +1046,11 @@ lfsck_layout_lastid_store(const struct lu_env *env,
                        continue;
                }
 
+               lastid = cpu_to_le64(lls->lls_lastid);
                rc = dt_declare_record_write(env, lls->lls_lastid_obj,
-                                            sizeof(lastid), pos, th);
+                                            lfsck_buf_get(env, &lastid,
+                                                          sizeof(lastid)),
+                                            pos, th);
                if (rc != 0)
                        goto stop;
 
@@ -1042,7 +1058,6 @@ lfsck_layout_lastid_store(const struct lu_env *env,
                if (rc != 0)
                        goto stop;
 
-               lastid = cpu_to_le64(lls->lls_lastid);
                dt_write_lock(env, lls->lls_lastid_obj, 0);
                rc = dt_record_write(env, lls->lls_lastid_obj,
                                     lfsck_buf_get(env, &lastid,
@@ -1593,64 +1608,922 @@ static int lfsck_layout_double_scan_result(const struct lu_env *env,
                spin_unlock(&lfsck->li_lock);
        }
 
-       rc = lfsck_layout_store(env, com);
+       rc = lfsck_layout_store(env, com);
+
+       up_write(&com->lc_sem);
+
+       return rc;
+}
+
+static int lfsck_layout_lock(const struct lu_env *env,
+                            struct lfsck_component *com,
+                            struct dt_object *obj,
+                            struct lustre_handle *lh, __u64 bits)
+{
+       struct lfsck_thread_info        *info   = lfsck_env_info(env);
+       ldlm_policy_data_t              *policy = &info->lti_policy;
+       struct ldlm_res_id              *resid  = &info->lti_resid;
+       struct lfsck_instance           *lfsck  = com->lc_lfsck;
+       __u64                            flags  = LDLM_FL_ATOMIC_CB;
+       int                              rc;
+
+       LASSERT(lfsck->li_namespace != NULL);
+
+       memset(policy, 0, sizeof(*policy));
+       policy->l_inodebits.bits = bits;
+       fid_build_reg_res_name(lfsck_dto2fid(obj), resid);
+       rc = ldlm_cli_enqueue_local(lfsck->li_namespace, resid, LDLM_IBITS,
+                                   policy, LCK_EX, &flags, ldlm_blocking_ast,
+                                   ldlm_completion_ast, NULL, NULL, 0,
+                                   LVB_T_NONE, NULL, lh);
+       if (rc == ELDLM_OK) {
+               rc = 0;
+       } else {
+               memset(lh, 0, sizeof(*lh));
+               rc = -EIO;
+       }
+
+       return rc;
+}
+
+static void lfsck_layout_unlock(struct lustre_handle *lh)
+{
+       if (lustre_handle_is_used(lh)) {
+               ldlm_lock_decref(lh, LCK_EX);
+               memset(lh, 0, sizeof(*lh));
+       }
+}
+
+static int lfsck_layout_trans_stop(const struct lu_env *env,
+                                  struct dt_device *dev,
+                                  struct thandle *handle, int result)
+{
+       int rc;
+
+       handle->th_result = result;
+       rc = dt_trans_stop(env, dev, handle);
+       if (rc > 0)
+               rc = 0;
+       else if (rc == 0)
+               rc = 1;
+
+       return rc;
+}
+
+/**
+ * \retval      +1: repaired
+ * \retval       0: did nothing
+ * \retval     -ve: on error
+ */
+static int lfsck_layout_refill_lovea(const struct lu_env *env,
+                                    struct thandle *handle,
+                                    struct dt_object *parent,
+                                    struct lu_fid *cfid,
+                                    struct lu_buf *buf,
+                                    struct lov_ost_data_v1 *slot,
+                                    int fl, __u32 ost_idx)
+{
+       struct ost_id   *oi     = &lfsck_env_info(env)->lti_oi;
+       int              rc;
+
+       fid_to_ostid(cfid, oi);
+       ostid_cpu_to_le(oi, &slot->l_ost_oi);
+       slot->l_ost_gen = cpu_to_le32(0);
+       slot->l_ost_idx = cpu_to_le32(ost_idx);
+       rc = dt_xattr_set(env, parent, buf, XATTR_NAME_LOV, fl, handle,
+                         BYPASS_CAPA);
+       if (rc == 0)
+               rc = 1;
+
+       return rc;
+}
+
+/**
+ * \retval      +1: repaired
+ * \retval       0: did nothing
+ * \retval     -ve: on error
+ */
+static int lfsck_layout_extend_lovea(const struct lu_env *env,
+                                    struct thandle *handle,
+                                    struct dt_object *parent,
+                                    struct lu_fid *cfid,
+                                    struct lu_buf *buf, int fl,
+                                    __u32 ost_idx, __u32 ea_off)
+{
+       struct lov_mds_md_v1    *lmm    = buf->lb_buf;
+       struct lov_ost_data_v1  *objs;
+       int                      rc;
+       ENTRY;
+
+       if (fl == LU_XATTR_CREATE) {
+               LASSERT(buf->lb_len == lov_mds_md_size(ea_off + 1,
+                                                      LOV_MAGIC_V1));
+
+               memset(lmm, 0, buf->lb_len);
+               lmm->lmm_magic = cpu_to_le32(LOV_MAGIC_V1);
+               /* XXX: currently, we only support LOV_PATTERN_RAID0. */
+               lmm->lmm_pattern = cpu_to_le32(LOV_PATTERN_RAID0);
+               fid_to_lmm_oi(lfsck_dto2fid(parent), &lmm->lmm_oi);
+               lmm_oi_cpu_to_le(&lmm->lmm_oi, &lmm->lmm_oi);
+               /* XXX: We cannot know the stripe size,
+                *      then use the default value (1 MB). */
+               lmm->lmm_stripe_size =
+                       cpu_to_le32(LOV_DESC_STRIPE_SIZE_DEFAULT);
+               objs = &(lmm->lmm_objects[ea_off]);
+       } else {
+               __u16   count = le16_to_cpu(lmm->lmm_stripe_count);
+               int     gap   = ea_off - count;
+               __u32   magic = le32_to_cpu(lmm->lmm_magic);
+
+               /* Currently, we only support LOV_MAGIC_V1/LOV_MAGIC_V3
+                * which has been verified in lfsck_layout_verify_header()
+                * already. If some new magic introduced in the future,
+                * then layout LFSCK needs to be updated also. */
+               if (magic == LOV_MAGIC_V1) {
+                       objs = &(lmm->lmm_objects[count]);
+               } else {
+                       LASSERT(magic == LOV_MAGIC_V3);
+                       objs = &((struct lov_mds_md_v3 *)lmm)->
+                                                       lmm_objects[count];
+               }
+
+               if (gap > 0)
+                       memset(objs, 0, gap * sizeof(*objs));
+               lmm->lmm_layout_gen =
+                           cpu_to_le16(le16_to_cpu(lmm->lmm_layout_gen) + 1);
+               objs += gap;
+
+               LASSERT(buf->lb_len == lov_mds_md_size(ea_off + 1, magic));
+       }
+
+       lmm->lmm_stripe_count = cpu_to_le16(ea_off + 1);
+       rc = lfsck_layout_refill_lovea(env, handle, parent, cfid, buf, objs,
+                                      fl, ost_idx);
+
+       RETURN(rc);
+}
+
+/**
+ * \retval      +1: repaired
+ * \retval       0: did nothing
+ * \retval     -ve: on error
+ */
+static int lfsck_layout_update_pfid(const struct lu_env *env,
+                                   struct lfsck_component *com,
+                                   struct dt_object *parent,
+                                   struct lu_fid *cfid,
+                                   struct dt_device *cdev, __u32 ea_off)
+{
+       struct filter_fid       *pfid   = &lfsck_env_info(env)->lti_new_pfid;
+       struct dt_object        *child;
+       struct thandle          *handle;
+       const struct lu_fid     *tfid   = lu_object_fid(&parent->do_lu);
+       struct lu_buf           *buf;
+       int                      rc     = 0;
+       ENTRY;
+
+       child = lfsck_object_find_by_dev(env, cdev, cfid);
+       if (IS_ERR(child))
+               RETURN(PTR_ERR(child));
+
+       handle = dt_trans_create(env, cdev);
+       if (IS_ERR(handle))
+               GOTO(out, rc = PTR_ERR(handle));
+
+       pfid->ff_parent.f_seq = cpu_to_le64(tfid->f_seq);
+       pfid->ff_parent.f_oid = cpu_to_le32(tfid->f_oid);
+       /* Currently, the filter_fid::ff_parent::f_ver is not the real parent
+        * MDT-object's FID::f_ver, instead it is the OST-object index in its
+        * parent MDT-object's layout EA. */
+       pfid->ff_parent.f_stripe_idx = cpu_to_le32(ea_off);
+       buf = lfsck_buf_get(env, pfid, sizeof(struct filter_fid));
+
+       rc = dt_declare_xattr_set(env, child, buf, XATTR_NAME_FID, 0, handle);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_trans_start(env, cdev, handle);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_xattr_set(env, child, buf, XATTR_NAME_FID, 0, handle,
+                         BYPASS_CAPA);
+
+       GOTO(stop, rc = (rc == 0 ? 1 : rc));
+
+stop:
+       dt_trans_stop(env, cdev, handle);
+
+out:
+       lu_object_put(env, &child->do_lu);
+
+       return rc;
+}
+
+/**
+ * \retval      +1: repaired
+ * \retval       0: did nothing
+ * \retval     -ve: on error
+ */
+static int lfsck_layout_recreate_parent(const struct lu_env *env,
+                                       struct lfsck_component *com,
+                                       struct lfsck_tgt_desc *ltd,
+                                       struct lu_orphan_rec *rec,
+                                       struct lu_fid *cfid,
+                                       const char *prefix,
+                                       const char *postfix,
+                                       __u32 ea_off)
+{
+       struct lfsck_thread_info        *info   = lfsck_env_info(env);
+       char                            *name   = info->lti_key;
+       struct lu_attr                  *la     = &info->lti_la;
+       struct dt_object_format         *dof    = &info->lti_dof;
+       struct lfsck_instance           *lfsck  = com->lc_lfsck;
+       struct lu_fid                   *pfid   = &rec->lor_fid;
+       struct lu_fid                   *tfid   = &info->lti_fid3;
+       struct dt_device                *next   = lfsck->li_next;
+       struct dt_object                *pobj   = NULL;
+       struct dt_object                *cobj   = NULL;
+       struct thandle                  *th     = NULL;
+       struct lu_buf                   *pbuf   = NULL;
+       struct lu_buf                   *ea_buf = &info->lti_big_buf;
+       struct lustre_handle             lh     = { 0 };
+       int                              buflen = ea_buf->lb_len;
+       int                              idx    = 0;
+       int                              rc     = 0;
+       ENTRY;
+
+       /* Create .lustre/lost+found/MDTxxxx when needed. */
+       if (unlikely(lfsck->li_lpf_obj == NULL)) {
+               rc = lfsck_create_lpf(env, lfsck);
+               if (rc != 0)
+                       RETURN(rc);
+       }
+
+       if (fid_is_zero(pfid)) {
+               struct filter_fid *ff = &info->lti_new_pfid;
+
+               rc = lfsck_fid_alloc(env, lfsck, pfid, false);
+               if (rc != 0)
+                       RETURN(rc);
+
+               ff->ff_parent.f_seq = cpu_to_le64(pfid->f_seq);
+               ff->ff_parent.f_oid = cpu_to_le32(pfid->f_oid);
+               /* Currently, the filter_fid::ff_parent::f_ver is not the
+                * real parent MDT-object's FID::f_ver, instead it is the
+                * OST-object index in its parent MDT-object's layout EA. */
+               ff->ff_parent.f_stripe_idx = cpu_to_le32(ea_off);
+               pbuf = lfsck_buf_get(env, ff, sizeof(struct filter_fid));
+               cobj = lfsck_object_find_by_dev(env, ltd->ltd_tgt, cfid);
+               if (IS_ERR(cobj))
+                       RETURN(PTR_ERR(cobj));
+       }
+
+       CDEBUG(D_LFSCK, "Re-create the lost MDT-object: parent "
+              DFID", child "DFID", OST-index %u, stripe-index %u, "
+              "prefix %s, postfix %s\n",
+              PFID(pfid), PFID(cfid), ltd->ltd_index, ea_off, prefix, postfix);
+
+       pobj = lfsck_object_find_by_dev(env, lfsck->li_bottom, pfid);
+       if (IS_ERR(pobj))
+               GOTO(put, rc = PTR_ERR(pobj));
+
+       LASSERT(prefix != NULL);
+       LASSERT(postfix != NULL);
+
+       /** name rules:
+        *
+        *  1. Use the MDT-object's FID as the name with prefix and postfix.
+        *
+        *  1.1 prefix "C-":    More than one OST-objects claim the same
+        *                      MDT-object and the same slot in the layout EA.
+        *                      It may be created for dangling referenced MDT
+        *                      object or may be not.
+        *  1.2 prefix "N-":    The orphan OST-object does not know which one
+        *                      is the real parent, so the LFSCK assign a new
+        *                      FID as its parent.
+        *  1.3 prefix "R-":    The orphan OST-object know its parent FID but
+        *                      does not know the position in the namespace.
+        *
+        *  2. If there is name conflict, append more index for new name. */
+       sprintf(name, "%s"DFID"%s", prefix, PFID(pfid), postfix);
+       do {
+               rc = dt_lookup(env, lfsck->li_lpf_obj, (struct dt_rec *)tfid,
+                              (const struct dt_key *)name, BYPASS_CAPA);
+               if (rc != 0 && rc != -ENOENT)
+                       GOTO(put, rc);
+
+               if (unlikely(rc == 0)) {
+                       CWARN("%s: The name %s under lost+found has been used "
+                             "by the "DFID". Try to increase the FID version "
+                             "for the new file name.\n",
+                             lfsck_lfsck2name(lfsck), name, PFID(tfid));
+                       sprintf(name, "%s"DFID"%s-%d", prefix, PFID(pfid),
+                               postfix, ++idx);
+               }
+       } while (rc == 0);
+
+       memset(la, 0, sizeof(*la));
+       la->la_uid = rec->lor_uid;
+       la->la_gid = rec->lor_gid;
+       la->la_mode = S_IFREG | S_IRUSR | S_IWUSR;
+       la->la_valid = LA_MODE | LA_UID | LA_GID;
+
+       memset(dof, 0, sizeof(*dof));
+       dof->dof_type = dt_mode_to_dft(S_IFREG);
+
+       rc = lov_mds_md_size(ea_off + 1, LOV_MAGIC_V1);
+       if (buflen < rc) {
+               lu_buf_realloc(ea_buf, rc);
+               buflen = ea_buf->lb_len;
+               if (ea_buf->lb_buf == NULL)
+                       GOTO(put, rc = -ENOMEM);
+       } else {
+               ea_buf->lb_len = rc;
+       }
+
+       /* Hold update lock on the .lustre/lost+found/MDTxxxx/.
+        *
+        * XXX: Currently, we do not grab the PDO lock as normal create cases,
+        *      because creating MDT-object for orphan OST-object is rare, we
+        *      do not much care about the performance. It can be improved in
+        *      the future when needed. */
+       rc = lfsck_layout_lock(env, com, lfsck->li_lpf_obj, &lh,
+                              MDS_INODELOCK_UPDATE);
+       if (rc != 0)
+               GOTO(put, rc);
+
+       th = dt_trans_create(env, next);
+       if (IS_ERR(th))
+               GOTO(unlock, rc = PTR_ERR(th));
+
+       /* 1a. Update OST-object's parent information remotely.
+        *
+        * If other subsequent modifications failed, then next LFSCK scanning
+        * will process the OST-object as orphan again with known parent FID. */
+       if (cobj != NULL) {
+               rc = dt_declare_xattr_set(env, cobj, pbuf, XATTR_NAME_FID, 0, th);
+               if (rc != 0)
+                       GOTO(stop, rc);
+       }
+
+       /* 2a. Create the MDT-object locally. */
+       rc = dt_declare_create(env, pobj, la, NULL, dof, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       /* 3a. Add layout EA for the MDT-object. */
+       rc = dt_declare_xattr_set(env, pobj, ea_buf, XATTR_NAME_LOV,
+                                 LU_XATTR_CREATE, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       /* 4a. Insert the MDT-object to .lustre/lost+found/MDTxxxx/ */
+       rc = dt_declare_insert(env, lfsck->li_lpf_obj,
+                              (const struct dt_rec *)pfid,
+                              (const struct dt_key *)name, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_trans_start(env, next, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       /* 1b. Update OST-object's parent information remotely. */
+       if (cobj != NULL) {
+               rc = dt_xattr_set(env, cobj, pbuf, XATTR_NAME_FID, 0, th,
+                                 BYPASS_CAPA);
+               if (rc != 0)
+                       GOTO(stop, rc);
+       }
+
+       dt_write_lock(env, pobj, 0);
+       /* 2b. Create the MDT-object locally. */
+       rc = dt_create(env, pobj, la, NULL, dof, th);
+       if (rc == 0)
+               /* 3b. Add layout EA for the MDT-object. */
+               rc = lfsck_layout_extend_lovea(env, th, pobj, cfid, ea_buf,
+                                              LU_XATTR_CREATE, ltd->ltd_index,
+                                              ea_off);
+       dt_write_unlock(env, pobj);
+       if (rc < 0)
+               GOTO(stop, rc);
+
+       /* 4b. Insert the MDT-object to .lustre/lost+found/MDTxxxx/ */
+       rc = dt_insert(env, lfsck->li_lpf_obj,
+                      (const struct dt_rec *)pfid,
+                      (const struct dt_key *)name, th, BYPASS_CAPA, 1);
+
+       GOTO(stop, rc);
+
+stop:
+       dt_trans_stop(env, next, th);
+
+unlock:
+       lfsck_layout_unlock(&lh);
+
+put:
+       if (cobj != NULL && !IS_ERR(cobj))
+               lu_object_put(env, &cobj->do_lu);
+       if (pobj != NULL && !IS_ERR(pobj))
+               lu_object_put(env, &pobj->do_lu);
+       ea_buf->lb_len = buflen;
+
+       return rc >= 0 ? 1 : rc;
+}
+
+static int lfsck_layout_master_conditional_destroy(const struct lu_env *env,
+                                                  struct lfsck_component *com,
+                                                  const struct lu_fid *fid,
+                                                  __u32 index)
+{
+       struct lfsck_thread_info *info  = lfsck_env_info(env);
+       struct lfsck_request     *lr    = &info->lti_lr;
+       struct lfsck_instance    *lfsck = com->lc_lfsck;
+       struct lfsck_tgt_desc    *ltd;
+       struct ptlrpc_request    *req;
+       struct lfsck_request     *tmp;
+       struct obd_export        *exp;
+       int                       rc    = 0;
+       ENTRY;
+
+       ltd = lfsck_tgt_get(&lfsck->li_ost_descs, index);
+       if (unlikely(ltd == NULL))
+               RETURN(-ENODEV);
+
+       exp = ltd->ltd_exp;
+       if (!(exp_connect_flags(exp) & OBD_CONNECT_LFSCK))
+               GOTO(put, rc = -EOPNOTSUPP);
+
+       req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_LFSCK_NOTIFY);
+       if (req == NULL)
+               GOTO(put, rc = -ENOMEM);
+
+       rc = ptlrpc_request_pack(req, LUSTRE_OBD_VERSION, LFSCK_NOTIFY);
+       if (rc != 0) {
+               ptlrpc_request_free(req);
+
+               GOTO(put, rc);
+       }
+
+       memset(lr, 0, sizeof(*lr));
+       lr->lr_event = LE_CONDITIONAL_DESTROY;
+       lr->lr_active = LT_LAYOUT;
+       lr->lr_fid = *fid;
+
+       tmp = req_capsule_client_get(&req->rq_pill, &RMF_LFSCK_REQUEST);
+       *tmp = *lr;
+       ptlrpc_request_set_replen(req);
+
+       rc = ptlrpc_queue_wait(req);
+       ptlrpc_req_finished(req);
+
+       GOTO(put, rc);
+
+put:
+       lfsck_tgt_put(ltd);
+
+       return rc;
+}
+
+static int lfsck_layout_slave_conditional_destroy(const struct lu_env *env,
+                                                 struct lfsck_component *com,
+                                                 struct lfsck_request *lr)
+{
+       struct lfsck_thread_info        *info   = lfsck_env_info(env);
+       struct lu_attr                  *la     = &info->lti_la;
+       ldlm_policy_data_t              *policy = &info->lti_policy;
+       struct ldlm_res_id              *resid  = &info->lti_resid;
+       struct lfsck_instance           *lfsck  = com->lc_lfsck;
+       struct dt_device                *dev    = lfsck->li_bottom;
+       struct lu_fid                   *fid    = &lr->lr_fid;
+       struct dt_object                *obj;
+       struct thandle                  *th     = NULL;
+       struct lustre_handle             lh     = { 0 };
+       __u64                            flags  = 0;
+       int                              rc     = 0;
+       ENTRY;
+
+       obj = lfsck_object_find_by_dev(env, dev, fid);
+       if (IS_ERR(obj))
+               RETURN(PTR_ERR(obj));
+
+       dt_read_lock(env, obj, 0);
+       if (dt_object_exists(obj) == 0) {
+               dt_read_unlock(env, obj);
+
+               GOTO(put, rc = -ENOENT);
+       }
+
+       /* Get obj's attr without lock firstly. */
+       rc = dt_attr_get(env, obj, la, BYPASS_CAPA);
+       dt_read_unlock(env, obj);
+       if (rc != 0)
+               GOTO(put, rc);
+
+       if (likely(la->la_ctime != 0 || la->la_mode & S_ISUID))
+               GOTO(put, rc = -ETXTBSY);
+
+       /* Acquire extent lock on [0, EOF] to sync with all possible written. */
+       LASSERT(lfsck->li_namespace != NULL);
+
+       memset(policy, 0, sizeof(*policy));
+       policy->l_extent.end = OBD_OBJECT_EOF;
+       ost_fid_build_resid(fid, resid);
+       rc = ldlm_cli_enqueue_local(lfsck->li_namespace, resid, LDLM_EXTENT,
+                                   policy, LCK_EX, &flags, ldlm_blocking_ast,
+                                   ldlm_completion_ast, NULL, NULL, 0,
+                                   LVB_T_NONE, NULL, &lh);
+       if (rc != ELDLM_OK)
+               GOTO(put, rc = -EIO);
+
+       dt_write_lock(env, obj, 0);
+       /* Get obj's attr within lock again. */
+       rc = dt_attr_get(env, obj, la, BYPASS_CAPA);
+       if (rc != 0)
+               GOTO(unlock, rc);
+
+       if (la->la_ctime != 0)
+               GOTO(unlock, rc = -ETXTBSY);
+
+       th = dt_trans_create(env, dev);
+       if (IS_ERR(th))
+               GOTO(unlock, rc = PTR_ERR(th));
+
+       rc = dt_declare_ref_del(env, obj, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_declare_destroy(env, obj, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_trans_start_local(env, dev, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_ref_del(env, obj, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_destroy(env, obj, th);
+       if (rc == 0)
+               CDEBUG(D_LFSCK, "Destroy the empty OST-object "DFID" which "
+                      "was created for reparing dangling referenced case. "
+                      "But the original missed OST-object is found now.\n",
+                      PFID(fid));
+
+       GOTO(stop, rc);
+
+stop:
+       dt_trans_stop(env, dev, th);
+
+unlock:
+       dt_write_unlock(env, obj);
+       ldlm_lock_decref(&lh, LCK_EX);
+
+put:
+       lu_object_put(env, &obj->do_lu);
+
+       return rc;
+}
+
+/**
+ * Some OST-object has occupied the specified layout EA slot.
+ * Such OST-object may be generated by the LFSCK when repair
+ * dangling referenced MDT-object, which can be indicated by
+ * attr::la_ctime == 0 but without S_ISUID in la_mode. If it
+ * is true and such OST-object has not been modified yet, we
+ * will replace it with the orphan OST-object; otherwise the
+ * LFSCK will create new MDT-object to reference the orphan.
+ *
+ * \retval      +1: repaired
+ * \retval       0: did nothing
+ * \retval     -ve: on error
+ */
+static int lfsck_layout_conflict_create(const struct lu_env *env,
+                                       struct lfsck_component *com,
+                                       struct lfsck_tgt_desc *ltd,
+                                       struct lu_orphan_rec *rec,
+                                       struct dt_object *parent,
+                                       struct lu_fid *cfid,
+                                       struct lu_buf *ea_buf,
+                                       struct lov_ost_data_v1 *slot,
+                                       __u32 ea_off, __u32 ori_len)
+{
+       struct lfsck_thread_info *info          = lfsck_env_info(env);
+       struct lu_fid            *cfid2         = &info->lti_fid2;
+       struct ost_id            *oi            = &info->lti_oi;
+       char                     *postfix       = info->lti_tmpbuf;
+       struct lov_mds_md_v1     *lmm           = ea_buf->lb_buf;
+       struct dt_device         *dev           = com->lc_lfsck->li_bottom;
+       struct thandle           *th            = NULL;
+       struct lustre_handle      lh            = { 0 };
+       __u32                     ost_idx2      = le32_to_cpu(slot->l_ost_idx);
+       int                       rc            = 0;
+       ENTRY;
+
+       ostid_le_to_cpu(&slot->l_ost_oi, oi);
+       ostid_to_fid(cfid2, oi, ost_idx2);
+
+       CDEBUG(D_LFSCK, "Handle layout EA conflict: parent "DFID
+              ", cur-child "DFID" on the OST %u, orphan-child "
+              DFID" on the OST %u, stripe-index %u\n",
+              PFID(lfsck_dto2fid(parent)), PFID(cfid2), ost_idx2,
+              PFID(cfid), ltd->ltd_index, ea_off);
+
+       /* Hold layout lock on the parent to prevent others to access. */
+       rc = lfsck_layout_lock(env, com, parent, &lh,
+                              MDS_INODELOCK_LAYOUT | MDS_INODELOCK_XATTR);
+       if (rc != 0)
+               GOTO(out, rc);
+
+       rc = lfsck_layout_master_conditional_destroy(env, com, cfid2, ost_idx2);
+
+       /* If the conflict OST-obejct is not created for fixing dangling
+        * referenced MDT-object in former LFSCK check/repair, or it has
+        * been modified by others, then we cannot destroy it. Re-create
+        * a new MDT-object for the orphan OST-object. */
+       if (rc == -ETXTBSY) {
+               /* No need the layout lock on the original parent. */
+               lfsck_layout_unlock(&lh);
+               ea_buf->lb_len = ori_len;
+
+               fid_zero(&rec->lor_fid);
+               snprintf(postfix, LFSCK_TMPBUF_LEN, "-"DFID"-%x",
+                        PFID(lu_object_fid(&parent->do_lu)), ea_off);
+               rc = lfsck_layout_recreate_parent(env, com, ltd, rec, cfid,
+                                                 "C-", postfix, ea_off);
+
+               RETURN(rc);
+       }
+
+       if (rc != 0 && rc != -ENOENT)
+               GOTO(unlock, rc);
+
+       th = dt_trans_create(env, dev);
+       if (IS_ERR(th))
+               GOTO(unlock, rc = PTR_ERR(th));
+
+       rc = dt_declare_xattr_set(env, parent, ea_buf, XATTR_NAME_LOV,
+                                 LU_XATTR_REPLACE, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_trans_start_local(env, dev, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       dt_write_lock(env, parent, 0);
+       lmm->lmm_layout_gen = cpu_to_le16(le16_to_cpu(lmm->lmm_layout_gen) + 1);
+       rc = lfsck_layout_refill_lovea(env, th, parent, cfid, ea_buf, slot,
+                                      LU_XATTR_REPLACE, ltd->ltd_index);
+       dt_write_unlock(env, parent);
+
+       GOTO(stop, rc);
+
+stop:
+       dt_trans_stop(env, dev, th);
+
+unlock:
+       lfsck_layout_unlock(&lh);
+
+out:
+       ea_buf->lb_len = ori_len;
+
+       return rc >= 0 ? 1 : rc;
+}
+
+/**
+ * \retval      +1: repaired
+ * \retval       0: did nothing
+ * \retval     -ve: on error
+ */
+static int lfsck_layout_recreate_lovea(const struct lu_env *env,
+                                      struct lfsck_component *com,
+                                      struct lfsck_tgt_desc *ltd,
+                                      struct lu_orphan_rec *rec,
+                                      struct dt_object *parent,
+                                      struct lu_fid *cfid,
+                                      __u32 ost_idx, __u32 ea_off)
+{
+       struct lfsck_thread_info *info          = lfsck_env_info(env);
+       struct lu_buf            *buf           = &info->lti_big_buf;
+       struct lu_fid            *fid           = &info->lti_fid2;
+       struct ost_id            *oi            = &info->lti_oi;
+       struct lfsck_instance    *lfsck         = com->lc_lfsck;
+       struct dt_device         *dt            = lfsck->li_bottom;
+       struct lfsck_bookmark    *bk            = &lfsck->li_bookmark_ram;
+       struct thandle            *handle       = NULL;
+       size_t                    buflen        = buf->lb_len;
+       struct lov_mds_md_v1     *lmm;
+       struct lov_ost_data_v1   *objs;
+       struct lustre_handle      lh            = { 0 };
+       __u32                     magic;
+       int                       fl            = 0;
+       int                       rc            = 0;
+       int                       rc1;
+       int                       i;
+       __u16                     count;
+       bool                      locked        = false;
+       ENTRY;
+
+       CDEBUG(D_LFSCK, "Re-create the crashed layout EA: parent "
+              DFID", child "DFID", OST-index %u, stripe-index %u\n",
+              PFID(lfsck_dto2fid(parent)), PFID(cfid), ost_idx, ea_off);
+
+       rc = lfsck_layout_lock(env, com, parent, &lh,
+                              MDS_INODELOCK_LAYOUT | MDS_INODELOCK_XATTR);
+       if (rc != 0)
+               RETURN(rc);
+
+again:
+       if (locked) {
+               dt_write_unlock(env, parent);
+               locked = false;
+       }
+
+       if (handle != NULL) {
+               dt_trans_stop(env, dt, handle);
+               handle = NULL;
+       }
+
+       if (rc < 0)
+               GOTO(unlock_layout, rc);
+
+       if (buf->lb_len < rc) {
+               lu_buf_realloc(buf, rc);
+               buflen = buf->lb_len;
+               if (buf->lb_buf == NULL)
+                       GOTO(unlock_layout, rc = -ENOMEM);
+       }
+
+       if (!(bk->lb_param & LPF_DRYRUN)) {
+               handle = dt_trans_create(env, dt);
+               if (IS_ERR(handle))
+                       GOTO(unlock_layout, rc = PTR_ERR(handle));
+
+               rc = dt_declare_xattr_set(env, parent, buf, XATTR_NAME_LOV,
+                                         fl, handle);
+               if (rc != 0)
+                       GOTO(stop, rc);
+
+               rc = dt_trans_start_local(env, dt, handle);
+               if (rc != 0)
+                       GOTO(stop, rc);
+       }
+
+       dt_write_lock(env, parent, 0);
+       locked = true;
+       rc = dt_xattr_get(env, parent, buf, XATTR_NAME_LOV, BYPASS_CAPA);
+       if (rc == -ERANGE) {
+               rc = dt_xattr_get(env, parent, &LU_BUF_NULL, XATTR_NAME_LOV,
+                                 BYPASS_CAPA);
+               LASSERT(rc != 0);
+               goto again;
+       } else if (rc == -ENODATA || rc == 0) {
+               rc = lov_mds_md_size(ea_off + 1, LOV_MAGIC_V1);
+               /* If the declared is not big enough, re-try. */
+               if (buf->lb_len < rc)
+                       goto again;
+
+               fl = LU_XATTR_CREATE;
+       } else if (rc < 0) {
+               GOTO(unlock_parent, rc);
+       } else if (unlikely(buf->lb_len == 0)) {
+               goto again;
+       } else {
+               fl = LU_XATTR_REPLACE;
+       }
+
+       if (fl == LU_XATTR_CREATE) {
+               if (bk->lb_param & LPF_DRYRUN)
+                       GOTO(unlock_parent, rc = 1);
+
+               LASSERT(buf->lb_len >= rc);
+
+               buf->lb_len = rc;
+               rc = lfsck_layout_extend_lovea(env, handle, parent, cfid, buf,
+                                              fl, ost_idx, ea_off);
+
+               GOTO(unlock_parent, rc);
+       }
+
+       lmm = buf->lb_buf;
+       rc1 = lfsck_layout_verify_header(lmm);
+       if (rc1 != 0)
+               GOTO(unlock_parent, rc = rc1);
+
+       /* Currently, we only support LOV_MAGIC_V1/LOV_MAGIC_V3 which has
+        * been verified in lfsck_layout_verify_header() already. If some
+        * new magic introduced in the future, then layout LFSCK needs to
+        * be updated also. */
+       magic = le32_to_cpu(lmm->lmm_magic);
+       if (magic == LOV_MAGIC_V1) {
+               objs = &(lmm->lmm_objects[0]);
+       } else {
+               LASSERT(magic == LOV_MAGIC_V3);
+               objs = &((struct lov_mds_md_v3 *)lmm)->lmm_objects[0];
+       }
+
+       count = le16_to_cpu(lmm->lmm_stripe_count);
+       if (count == 0)
+               GOTO(unlock_parent, rc = -EINVAL);
+       LASSERT(count > 0);
+
+       /* Exceed the current end of MDT-object layout EA. Then extend it. */
+       if (count <= ea_off) {
+               if (bk->lb_param & LPF_DRYRUN)
+                       GOTO(unlock_parent, rc = 1);
+
+               rc = lov_mds_md_size(ea_off + 1, magic);
+               /* If the declared is not big enough, re-try. */
+               if (buf->lb_len < rc)
+                       goto again;
+
+               buf->lb_len = rc;
+               rc = lfsck_layout_extend_lovea(env, handle, parent, cfid, buf,
+                                              fl, ost_idx, ea_off);
+               GOTO(unlock_parent, rc);
+       }
 
-       up_write(&com->lc_sem);
+       LASSERTF(rc > 0, "invalid rc = %d\n", rc);
 
-       return rc;
-}
+       buf->lb_len = rc;
+       for (i = 0; i < count; i++, objs++) {
+               /* The MDT-object was created via lfsck_layout_recover_create()
+                * by others before, and we fill the dummy layout EA. */
+               if (is_dummy_lov_ost_data(objs)) {
+                       if (i != ea_off)
+                               continue;
 
-static int lfsck_layout_lock(const struct lu_env *env,
-                            struct lfsck_component *com,
-                            struct dt_object *obj,
-                            struct lustre_handle *lh, __u64 bits)
-{
-       struct lfsck_thread_info        *info   = lfsck_env_info(env);
-       ldlm_policy_data_t              *policy = &info->lti_policy;
-       struct ldlm_res_id              *resid  = &info->lti_resid;
-       struct lfsck_instance           *lfsck  = com->lc_lfsck;
-       __u64                            flags  = LDLM_FL_ATOMIC_CB;
-       int                              rc;
+                       if (bk->lb_param & LPF_DRYRUN)
+                               GOTO(unlock_parent, rc = 1);
 
-       LASSERT(lfsck->li_namespace != NULL);
+                       lmm->lmm_layout_gen =
+                           cpu_to_le16(le16_to_cpu(lmm->lmm_layout_gen) + 1);
+                       rc = lfsck_layout_refill_lovea(env, handle, parent,
+                                                      cfid, buf, objs, fl,
+                                                      ost_idx);
+                       GOTO(unlock_parent, rc);
+               }
 
-       memset(policy, 0, sizeof(*policy));
-       policy->l_inodebits.bits = bits;
-       fid_build_reg_res_name(lfsck_dto2fid(obj), resid);
-       rc = ldlm_cli_enqueue_local(lfsck->li_namespace, resid, LDLM_IBITS,
-                                   policy, LCK_EX, &flags, ldlm_blocking_ast,
-                                   ldlm_completion_ast, NULL, NULL, 0,
-                                   LVB_T_NONE, NULL, lh);
-       if (rc == ELDLM_OK) {
-               rc = 0;
-       } else {
-               memset(lh, 0, sizeof(*lh));
-               rc = -EIO;
+               ostid_le_to_cpu(&objs->l_ost_oi, oi);
+               ostid_to_fid(fid, oi, le32_to_cpu(objs->l_ost_idx));
+               /* It should be rare case, the slot is there, but the LFSCK
+                * does not handle it during the first-phase cycle scanning. */
+               if (unlikely(lu_fid_eq(fid, cfid))) {
+                       if (i == ea_off) {
+                               GOTO(unlock_parent, rc = 0);
+                       } else {
+                               /* Rare case that the OST-object index
+                                * does not match the parent MDT-object
+                                * layout EA. We trust the later one. */
+                               if (bk->lb_param & LPF_DRYRUN)
+                                       GOTO(unlock_parent, rc = 1);
+
+                               dt_write_unlock(env, parent);
+                               if (handle != NULL)
+                                       dt_trans_stop(env, dt, handle);
+                               lfsck_layout_unlock(&lh);
+                               buf->lb_len = buflen;
+                               rc = lfsck_layout_update_pfid(env, com, parent,
+                                                       cfid, ltd->ltd_tgt, i);
+
+                               RETURN(rc);
+                       }
+               }
        }
 
-       return rc;
-}
+       /* The MDT-object exists, but related layout EA slot is occupied
+        * by others. */
+       if (bk->lb_param & LPF_DRYRUN)
+               GOTO(unlock_parent, rc = 1);
 
-static void lfsck_layout_unlock(struct lustre_handle *lh)
-{
-       if (lustre_handle_is_used(lh)) {
-               ldlm_lock_decref(lh, LCK_EX);
-               memset(lh, 0, sizeof(*lh));
-       }
-}
+       dt_write_unlock(env, parent);
+       if (handle != NULL)
+               dt_trans_stop(env, dt, handle);
+       lfsck_layout_unlock(&lh);
+       if (le32_to_cpu(lmm->lmm_magic) == LOV_MAGIC_V1)
+               objs = &(lmm->lmm_objects[ea_off]);
+       else
+               objs = &((struct lov_mds_md_v3 *)lmm)->lmm_objects[ea_off];
+       rc = lfsck_layout_conflict_create(env, com, ltd, rec, parent, cfid,
+                                         buf, objs, ea_off, buflen);
 
-static int lfsck_layout_trans_stop(const struct lu_env *env,
-                                  struct dt_device *dev,
-                                  struct thandle *handle, int result)
-{
-       int rc;
+       RETURN(rc);
 
-       handle->th_result = result;
-       rc = dt_trans_stop(env, dev, handle);
-       if (rc > 0)
-               rc = 0;
-       else if (rc == 0)
-               rc = 1;
+unlock_parent:
+       if (locked)
+               dt_write_unlock(env, parent);
+
+stop:
+       if (handle != NULL)
+               dt_trans_stop(env, dt, handle);
+
+unlock_layout:
+       lfsck_layout_unlock(&lh);
+       buf->lb_len = buflen;
 
        return rc;
 }
@@ -1661,11 +2534,56 @@ static int lfsck_layout_scan_orphan_one(const struct lu_env *env,
                                        struct lu_orphan_rec *rec,
                                        struct lu_fid *cfid)
 {
-       struct lfsck_layout             *lo     = com->lc_file_ram;
-       int                              rc     = 0;
+       struct lfsck_layout     *lo     = com->lc_file_ram;
+       struct lu_fid           *pfid   = &rec->lor_fid;
+       struct dt_object        *parent = NULL;
+       __u32                    ea_off = pfid->f_stripe_idx;
+       int                      rc     = 0;
+       ENTRY;
+
+       if (!fid_is_sane(cfid))
+               GOTO(out, rc = -EINVAL);
+
+       if (fid_is_zero(pfid)) {
+               rc = lfsck_layout_recreate_parent(env, com, ltd, rec, cfid,
+                                                 "N-", "", ea_off);
+               GOTO(out, rc);
+       }
+
+       pfid->f_ver = 0;
+       if (!fid_is_sane(pfid))
+               GOTO(out, rc = -EINVAL);
+
+       parent = lfsck_object_find_by_dev(env, com->lc_lfsck->li_bottom, pfid);
+       if (IS_ERR(parent))
+               GOTO(out, rc = PTR_ERR(parent));
 
-       /* XXX: To be extended in other patch. */
+       if (unlikely(dt_object_remote(parent) != 0))
+               GOTO(put, rc = -EXDEV);
 
+       if (dt_object_exists(parent) == 0) {
+               lu_object_put(env, &parent->do_lu);
+               rc = lfsck_layout_recreate_parent(env, com, ltd, rec, cfid,
+                                                 "R-", "", ea_off);
+               GOTO(out, rc);
+       }
+
+       if (!S_ISREG(lu_object_attr(&parent->do_lu)))
+               GOTO(put, rc = -EISDIR);
+
+       rc = lfsck_layout_recreate_lovea(env, com, ltd, rec, parent, cfid,
+                                        ltd->ltd_index, ea_off);
+
+       GOTO(put, rc);
+
+put:
+       if (rc <= 0)
+               lu_object_put(env, &parent->do_lu);
+       else
+               /* The layout EA is changed, need to be reloaded next time. */
+               lu_object_put_nocache(env, &parent->do_lu);
+
+out:
        down_write(&com->lc_sem);
        com->lc_new_scanned++;
        com->lc_new_checked++;
@@ -1738,6 +2656,18 @@ static int lfsck_layout_scan_orphan(const struct lu_env *env,
                struct dt_key           *key;
                struct lu_orphan_rec    *rec = &info->lti_rec;
 
+               if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_DELAY3) &&
+                   cfs_fail_val > 0) {
+                       struct ptlrpc_thread    *thread = &lfsck->li_thread;
+                       struct l_wait_info       lwi;
+
+                       lwi = LWI_TIMEOUT(cfs_time_seconds(cfs_fail_val),
+                                         NULL, NULL);
+                       l_wait_event(thread->t_ctl_waitq,
+                                    !thread_is_running(thread),
+                                    &lwi);
+               }
+
                key = iops->key(env, di);
                com->lc_fid_latest_scanned_phase2 = *(struct lu_fid *)key;
                rc = iops->rec(env, di, (struct dt_rec *)rec, 0);
@@ -1805,7 +2735,10 @@ static int lfsck_layout_recreate_ostobj(const struct lu_env *env,
        hint->dah_mode = 0;
        pfid->ff_parent.f_seq = cpu_to_le64(tfid->f_seq);
        pfid->ff_parent.f_oid = cpu_to_le32(tfid->f_oid);
-       pfid->ff_parent.f_ver = cpu_to_le32(llr->llr_lov_idx);
+       /* Currently, the filter_fid::ff_parent::f_ver is not the real parent
+        * MDT-object's FID::f_ver, instead it is the OST-object index in its
+        * parent MDT-object's layout EA. */
+       pfid->ff_parent.f_stripe_idx = cpu_to_le32(llr->llr_lov_idx);
        buf = lfsck_buf_get(env, pfid, sizeof(struct filter_fid));
 
        rc = dt_declare_create(env, child, la, hint, NULL, handle);
@@ -1883,9 +2816,10 @@ static int lfsck_layout_repair_unmatched_pair(const struct lu_env *env,
 
        pfid->ff_parent.f_seq = cpu_to_le64(tfid->f_seq);
        pfid->ff_parent.f_oid = cpu_to_le32(tfid->f_oid);
-       /* The ff_parent->f_ver is not the real parent fid->f_ver. Instead,
-        * it is the OST-object index in the parent MDT-object layout. */
-       pfid->ff_parent.f_ver = cpu_to_le32(llr->llr_lov_idx);
+       /* Currently, the filter_fid::ff_parent::f_ver is not the real parent
+        * MDT-object's FID::f_ver, instead it is the OST-object index in its
+        * parent MDT-object's layout EA. */
+       pfid->ff_parent.f_stripe_idx = cpu_to_le32(llr->llr_lov_idx);
        buf = lfsck_buf_get(env, pfid, sizeof(struct filter_fid));
 
        rc = dt_declare_xattr_set(env, child, buf, XATTR_NAME_FID, 0, handle);
@@ -2222,6 +3156,9 @@ static int lfsck_layout_check_parent(const struct lu_env *env,
                struct lu_fid           *tfid   = &info->lti_fid2;
                struct ost_id           *oi     = &info->lti_oi;
 
+               if (is_dummy_lov_ost_data(objs))
+                       continue;
+
                ostid_le_to_cpu(&objs->l_ost_oi, oi);
                ostid_to_fid(tfid, oi, le32_to_cpu(objs->l_ost_idx));
                if (lu_fid_eq(cfid, tfid)) {
@@ -2294,10 +3231,10 @@ static int lfsck_layout_assistant_handle_one(const struct lu_env *env,
                fid_zero(pfid);
        } else {
                fid_le_to_cpu(pfid, &pea->ff_parent);
-               /* OST-object does not save parent FID::f_ver, instead,
-                * the OST-object index in the parent MDT-object layout
-                * EA reuses the pfid->f_ver. */
-               idx = pfid->f_ver;
+               /* Currently, the filter_fid::ff_parent::f_ver is not the
+                * real parent MDT-object's FID::f_ver, instead it is the
+                * OST-object index in its parent MDT-object's layout EA. */
+               idx = pfid->f_stripe_idx;
                pfid->f_ver = 0;
        }
 
@@ -2440,11 +3377,15 @@ static int lfsck_layout_assistant(void *args)
                        rc = lfsck_layout_assistant_handle_one(env, com, llr);
                        spin_lock(&llmd->llmd_lock);
                        list_del_init(&llr->llr_list);
-                       if (bk->lb_async_windows != 0 &&
-                           llmd->llmd_prefetched >= bk->lb_async_windows)
-                               wakeup = true;
-
                        llmd->llmd_prefetched--;
+                       /* Wake up the main engine thread only when the list
+                        * is empty or half of the prefetched items have been
+                        * handled to avoid too frequent thread schedule. */
+                       if (llmd->llmd_prefetched == 0 ||
+                           (bk->lb_async_windows != 0 &&
+                            bk->lb_async_windows / 2 ==
+                            llmd->llmd_prefetched))
+                               wakeup = true;
                        spin_unlock(&llmd->llmd_lock);
                        if (wakeup)
                                wake_up_all(&mthread->t_ctl_waitq);
@@ -2454,9 +3395,6 @@ static int lfsck_layout_assistant(void *args)
                                GOTO(cleanup1, rc);
                }
 
-               /* Wakeup the master engine if it is waiting in checkpoint. */
-               wake_up_all(&mthread->t_ctl_waitq);
-
                l_wait_event(athread->t_ctl_waitq,
                             !lfsck_layout_req_empty(llmd) ||
                             llmd->llmd_exit ||
@@ -2887,6 +3825,209 @@ lfsck_layout_slave_notify_master(const struct lu_env *env,
        RETURN_EXIT;
 }
 
+/*
+ * \ret -ENODATA: unrecognized stripe
+ * \ret = 0     : recognized stripe
+ * \ret < 0     : other failures
+ */
+static int lfsck_layout_master_check_pairs(const struct lu_env *env,
+                                          struct lfsck_component *com,
+                                          struct lu_fid *cfid,
+                                          struct lu_fid *pfid)
+{
+       struct lfsck_thread_info        *info   = lfsck_env_info(env);
+       struct lu_buf                   *buf    = &info->lti_big_buf;
+       struct ost_id                   *oi     = &info->lti_oi;
+       struct dt_object                *obj;
+       struct lov_mds_md_v1            *lmm;
+       struct lov_ost_data_v1          *objs;
+       __u32                            idx    = pfid->f_stripe_idx;
+       __u32                            magic;
+       int                              rc     = 0;
+       int                              i;
+       __u16                            count;
+       ENTRY;
+
+       pfid->f_ver = 0;
+       obj = lfsck_object_find_by_dev(env, com->lc_lfsck->li_bottom, pfid);
+       if (IS_ERR(obj))
+               RETURN(PTR_ERR(obj));
+
+       dt_read_lock(env, obj, 0);
+       if (unlikely(!dt_object_exists(obj)))
+               GOTO(unlock, rc = -ENOENT);
+
+       rc = lfsck_layout_get_lovea(env, obj, buf, NULL);
+       if (rc < 0)
+               GOTO(unlock, rc);
+
+       if (rc == 0)
+               GOTO(unlock, rc = -ENODATA);
+
+       lmm = buf->lb_buf;
+       rc = lfsck_layout_verify_header(lmm);
+       if (rc != 0)
+               GOTO(unlock, rc);
+
+       /* Currently, we only support LOV_MAGIC_V1/LOV_MAGIC_V3 which has
+        * been verified in lfsck_layout_verify_header() already. If some
+        * new magic introduced in the future, then layout LFSCK needs to
+        * be updated also. */
+       magic = le32_to_cpu(lmm->lmm_magic);
+       if (magic == LOV_MAGIC_V1) {
+               objs = &(lmm->lmm_objects[0]);
+       } else {
+               LASSERT(magic == LOV_MAGIC_V3);
+               objs = &((struct lov_mds_md_v3 *)lmm)->lmm_objects[0];
+       }
+
+       fid_to_ostid(cfid, oi);
+       count = le16_to_cpu(lmm->lmm_stripe_count);
+       for (i = 0; i < count; i++, objs++) {
+               struct ost_id oi2;
+
+               ostid_le_to_cpu(&objs->l_ost_oi, &oi2);
+               if (memcmp(oi, &oi2, sizeof(*oi)) == 0)
+                       GOTO(unlock, rc = (i != idx ? -ENODATA : 0));
+       }
+
+       GOTO(unlock, rc = -ENODATA);
+
+unlock:
+       dt_read_unlock(env, obj);
+       lu_object_put(env, &obj->do_lu);
+
+       return rc;
+}
+
+/*
+ * The LFSCK-on-OST will ask the LFSCK-on-MDT to check whether the given
+ * MDT-object/OST-object pairs match or not to aviod transfer MDT-object
+ * layout EA from MDT to OST. On one hand, the OST no need to understand
+ * the layout EA structure; on the other hand, it may cause trouble when
+ * transfer large layout EA from MDT to OST via normal OUT RPC.
+ *
+ * \ret > 0: unrecognized stripe
+ * \ret = 0: recognized stripe
+ * \ret < 0: other failures
+ */
+static int lfsck_layout_slave_check_pairs(const struct lu_env *env,
+                                         struct lfsck_component *com,
+                                         struct lu_fid *cfid,
+                                         struct lu_fid *pfid)
+{
+       struct lfsck_instance    *lfsck  = com->lc_lfsck;
+       struct obd_device        *obd    = lfsck->li_obd;
+       struct seq_server_site   *ss     =
+                       lu_site2seq(lfsck->li_bottom->dd_lu_dev.ld_site);
+       struct obd_export        *exp    = NULL;
+       struct ptlrpc_request    *req    = NULL;
+       struct lfsck_request     *lr;
+       struct lu_seq_range       range  = { 0 };
+       int                       rc     = 0;
+       ENTRY;
+
+       if (unlikely(fid_is_idif(pfid)))
+               RETURN(1);
+
+       fld_range_set_any(&range);
+       rc = fld_server_lookup(env, ss->ss_server_fld, fid_seq(pfid), &range);
+       if (rc != 0)
+               RETURN(rc == -ENOENT ? 1 : rc);
+
+       if (unlikely(!fld_range_is_mdt(&range)))
+               RETURN(1);
+
+       exp = lustre_find_lwp_by_index(obd->obd_name, range.lsr_index);
+       if (unlikely(exp == NULL))
+               RETURN(1);
+
+       if (!(exp_connect_flags(exp) & OBD_CONNECT_LFSCK))
+               GOTO(out, rc = -EOPNOTSUPP);
+
+       req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_LFSCK_NOTIFY);
+       if (req == NULL)
+               GOTO(out, rc = -ENOMEM);
+
+       rc = ptlrpc_request_pack(req, LUSTRE_OBD_VERSION, LFSCK_NOTIFY);
+       if (rc != 0) {
+               ptlrpc_request_free(req);
+
+               GOTO(out, rc);
+       }
+
+       lr = req_capsule_client_get(&req->rq_pill, &RMF_LFSCK_REQUEST);
+       memset(lr, 0, sizeof(*lr));
+       lr->lr_event = LE_PAIRS_VERIFY;
+       lr->lr_active = LT_LAYOUT;
+       lr->lr_fid = *cfid; /* OST-object itself FID. */
+       lr->lr_fid2 = *pfid; /* The claimed parent FID. */
+
+       ptlrpc_request_set_replen(req);
+       rc = ptlrpc_queue_wait(req);
+       ptlrpc_req_finished(req);
+
+       if (rc == -ENOENT || rc == -ENODATA)
+               rc = 1;
+
+       GOTO(out, rc);
+
+out:
+       if (exp != NULL)
+               class_export_put(exp);
+
+       return rc;
+}
+
+static int lfsck_layout_slave_repair_pfid(const struct lu_env *env,
+                                         struct lfsck_component *com,
+                                         struct lfsck_request *lr)
+{
+       struct lfsck_thread_info        *info   = lfsck_env_info(env);
+       struct filter_fid               *ff     = &info->lti_new_pfid;
+       struct lu_buf                   *buf;
+       struct dt_device                *dev    = com->lc_lfsck->li_bottom;
+       struct dt_object                *obj;
+       struct thandle                  *th     = NULL;
+       int                              rc     = 0;
+       ENTRY;
+
+       obj = lfsck_object_find_by_dev(env, dev, &lr->lr_fid);
+       if (IS_ERR(obj))
+               RETURN(PTR_ERR(obj));
+
+       fid_cpu_to_le(&ff->ff_parent, &lr->lr_fid2);
+       buf = lfsck_buf_get(env, ff, sizeof(*ff));
+       dt_write_lock(env, obj, 0);
+       if (unlikely(!dt_object_exists(obj)))
+               GOTO(unlock, rc = 0);
+
+       th = dt_trans_create(env, dev);
+       if (IS_ERR(th))
+               GOTO(unlock, rc = PTR_ERR(th));
+
+       rc = dt_declare_xattr_set(env, obj, buf, XATTR_NAME_FID, 0, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_trans_start_local(env, dev, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_xattr_set(env, obj, buf, XATTR_NAME_FID, 0, th, BYPASS_CAPA);
+
+       GOTO(stop, rc);
+
+stop:
+       dt_trans_stop(env, dev, th);
+
+unlock:
+       dt_write_unlock(env, obj);
+       lu_object_put(env, &obj->do_lu);
+
+       return rc;
+}
+
 /* layout APIs */
 
 static int lfsck_layout_reset(const struct lu_env *env,
@@ -3194,6 +4335,9 @@ static int lfsck_layout_scan_stripes(const struct lu_env *env,
                                        le32_to_cpu(objs->l_ost_idx);
                bool                     wakeup = false;
 
+               if (is_dummy_lov_ost_data(objs))
+                       continue;
+
                l_wait_event(mthread->t_ctl_waitq,
                             bk->lb_async_windows == 0 ||
                             llmd->llmd_prefetched < bk->lb_async_windows ||
@@ -4070,6 +5214,15 @@ static int lfsck_layout_master_in_notify(const struct lu_env *env,
        bool                             fail  = false;
        ENTRY;
 
+       if (lr->lr_event == LE_PAIRS_VERIFY) {
+               int rc;
+
+               rc = lfsck_layout_master_check_pairs(env, com, &lr->lr_fid,
+                                                    &lr->lr_fid2);
+
+               RETURN(rc);
+       }
+
        if (lr->lr_event != LE_PHASE1_DONE &&
            lr->lr_event != LE_PHASE2_DONE &&
            lr->lr_event != LE_PEER_EXIT)
@@ -4158,16 +5311,55 @@ static int lfsck_layout_slave_in_notify(const struct lu_env *env,
        struct lfsck_instance            *lfsck = com->lc_lfsck;
        struct lfsck_layout_slave_data   *llsd  = com->lc_data;
        struct lfsck_layout_slave_target *llst;
+       int                               rc;
        ENTRY;
 
-       if (lr->lr_event == LE_FID_ACCESSED) {
+       switch (lr->lr_event) {
+       case LE_FID_ACCESSED:
                lfsck_rbtree_update_bitmap(env, com, &lr->lr_fid, true);
-
                RETURN(0);
-       }
+       case LE_CONDITIONAL_DESTROY:
+               rc = lfsck_layout_slave_conditional_destroy(env, com, lr);
+               RETURN(rc);
+       case LE_PAIRS_VERIFY: {
+               lr->lr_status = LPVS_INIT;
+               /* Firstly, if the MDT-object which is claimed via OST-object
+                * local stored PFID xattr recognizes the OST-object, then it
+                * must be that the client given PFID is wrong. */
+               rc = lfsck_layout_slave_check_pairs(env, com, &lr->lr_fid,
+                                                   &lr->lr_fid3);
+               if (rc <= 0)
+                       RETURN(0);
+
+               lr->lr_status = LPVS_INCONSISTENT;
+               /* The OST-object local stored PFID xattr is stale. We need to
+                * check whether the MDT-object that is claimed via the client
+                * given PFID information recognizes the OST-object or not. If
+                * matches, then need to update the OST-object's PFID xattr. */
+               rc = lfsck_layout_slave_check_pairs(env, com, &lr->lr_fid,
+                                                   &lr->lr_fid2);
+               /* For rc < 0 case:
+                * We are not sure whether the client given PFID information
+                * is correct or not, do nothing to avoid improper fixing.
+                *
+                * For rc > 0 case:
+                * The client given PFID information is also invalid, we can
+                * NOT fix the OST-object inconsistency.
+                */
+               if (rc != 0)
+                       RETURN(rc);
 
-       if (lr->lr_event != LE_PHASE2_DONE && lr->lr_event != LE_PEER_EXIT)
+               lr->lr_status = LPVS_INCONSISTENT_TOFIX;
+               rc = lfsck_layout_slave_repair_pfid(env, com, lr);
+
+               RETURN(rc);
+       }
+       case LE_PHASE2_DONE:
+       case LE_PEER_EXIT:
+               break;
+       default:
                RETURN(-EINVAL);
+       }
 
        llst = lfsck_layout_llst_find_and_del(llsd, lr->lr_index, true);
        if (llst == NULL)
@@ -4622,7 +5814,7 @@ static struct dt_it *lfsck_orphan_it_init(const struct lu_env *env,
                GOTO(out, rc = -ENODEV);
 
        if (dev->dd_record_fid_accessed) {
-               /* The first iteratino against the rbtree, scan the whole rbtree
+               /* The first iteration against the rbtree, scan the whole rbtree
                 * to remove the nodes which do NOT need to be handled. */
                write_lock(&llsd->llsd_rb_lock);
                if (dev->dd_record_fid_accessed) {
@@ -4863,10 +6055,10 @@ again1:
                GOTO(out, rc = -EINVAL);
 
        fid_le_to_cpu(&rec->lor_fid, &pfid->ff_parent);
-       /* In fact, the ff_parent::f_ver is not the real parent FID::f_ver,
-        * instead, it is the OST-object index in its parent MDT-object
-        * layout EA. */
-       save = rec->lor_fid.f_ver;
+       /* Currently, the filter_fid::ff_parent::f_ver is not the real parent
+        * MDT-object's FID::f_ver, instead it is the OST-object index in its
+        * parent MDT-object's layout EA. */
+       save = rec->lor_fid.f_stripe_idx;
        rec->lor_fid.f_ver = 0;
        rc = lfsck_fid_match_idx(env, lfsck, &rec->lor_fid, idx);
        /* If the orphan OST-object does not claim the MDT, then next.
@@ -4880,7 +6072,7 @@ again1:
                goto again1;
        }
 
-       rec->lor_fid.f_ver = save;
+       rec->lor_fid.f_stripe_idx = save;
        rec->lor_uid = la->la_uid;
        rec->lor_gid = la->la_gid;