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LU-1267 lfsck: framework (3) for MDT-OST consistency
[fs/lustre-release.git] / lustre / lfsck / lfsck_layout.c
index 402cca7..39cffe3 100644 (file)
@@ -43,6 +43,8 @@
 #include <lustre_lib.h>
 #include <lustre_net.h>
 #include <lustre/lustre_user.h>
+#include <md_object.h>
+#include <obd_class.h>
 
 #include "lfsck_internal.h"
 
 
 static const char lfsck_layout_name[] = "lfsck_layout";
 
+struct lfsck_layout_seq {
+       struct list_head         lls_list;
+       __u64                    lls_seq;
+       __u64                    lls_lastid;
+       __u64                    lls_lastid_known;
+       struct dt_object        *lls_lastid_obj;
+       unsigned int             lls_dirty:1;
+};
+
+struct lfsck_layout_slave_data {
+       /* list for lfsck_layout_seq */
+       struct list_head         llsd_seq_list;
+};
+
+struct lfsck_layout_object {
+       struct dt_object        *llo_obj;
+       struct lu_attr           llo_attr;
+       atomic_t                 llo_ref;
+       __u16                    llo_gen;
+};
+
+struct lfsck_layout_req {
+       struct list_head                 llr_list;
+       struct lfsck_layout_object      *llr_parent;
+       struct dt_object                *llr_child;
+       __u32                            llr_ost_idx;
+       __u32                            llr_lov_idx; /* offset in LOV EA */
+};
+
+struct lfsck_layout_master_data {
+       struct list_head        llmd_req_list;
+       spinlock_t              llmd_lock;
+       struct ptlrpc_thread    llmd_thread;
+       atomic_t                llmd_rpcs_in_flight;
+       int                     llmd_prefetched;
+       int                     llmd_assistant_status;
+       int                     llmd_post_result;
+       unsigned int            llmd_to_post:1,
+                               llmd_to_double_scan:1,
+                               llmd_in_double_scan:1,
+                               llmd_exit:1;
+};
+
+static inline void lfsck_layout_object_put(const struct lu_env *env,
+                                          struct lfsck_layout_object *llo)
+{
+       if (atomic_dec_and_test(&llo->llo_ref)) {
+               lfsck_object_put(env, llo->llo_obj);
+               OBD_FREE_PTR(llo);
+       }
+}
+
+static inline void lfsck_layout_req_fini(const struct lu_env *env,
+                                        struct lfsck_layout_req *llr)
+{
+       lu_object_put(env, &llr->llr_child->do_lu);
+       lfsck_layout_object_put(env, llr->llr_parent);
+       OBD_FREE_PTR(llr);
+}
+
+static inline bool lfsck_layout_req_empty(struct lfsck_layout_master_data *llmd)
+{
+       bool empty = false;
+
+       spin_lock(&llmd->llmd_lock);
+       if (list_empty(&llmd->llmd_req_list))
+               empty = true;
+       spin_unlock(&llmd->llmd_lock);
+
+       return empty;
+}
+
 static void lfsck_layout_le_to_cpu(struct lfsck_layout *des,
                                   const struct lfsck_layout *src)
 {
@@ -213,8 +287,635 @@ static int lfsck_layout_init(const struct lu_env *env,
        return rc;
 }
 
+static int fid_is_for_ostobj(const struct lu_env *env, struct dt_device *dt,
+                            struct dt_object *obj, const struct lu_fid *fid)
+{
+       struct seq_server_site  *ss     = lu_site2seq(dt->dd_lu_dev.ld_site);
+       struct lu_seq_range      range  = { 0 };
+       struct lustre_mdt_attrs *lma;
+       int                      rc;
+
+       fld_range_set_any(&range);
+       rc = fld_server_lookup(env, ss->ss_server_fld, fid_seq(fid), &range);
+       if (rc == 0) {
+               if (fld_range_is_ost(&range))
+                       return 1;
+
+               return 0;
+       }
+
+       lma = &lfsck_env_info(env)->lti_lma;
+       rc = dt_xattr_get(env, obj, lfsck_buf_get(env, lma, sizeof(*lma)),
+                         XATTR_NAME_LMA, BYPASS_CAPA);
+       if (rc == sizeof(*lma)) {
+               lustre_lma_swab(lma);
+
+               /* Generally, the low layer OSD create handler or OI scrub
+                * will set the LMAC_FID_ON_OST for all external visible
+                * OST-objects. But to make the otable-based iteration to
+                * be independent from OI scrub in spite of it got failure
+                * or not, we check the LMAC_FID_ON_OST here to guarantee
+                * that the LFSCK will not repair something by wrong. */
+               return lma->lma_compat & LMAC_FID_ON_OST ? 1 : 0;
+       }
+
+       rc = dt_xattr_get(env, obj, &LU_BUF_NULL, XATTR_NAME_FID, BYPASS_CAPA);
+
+       return rc > 0;
+}
+
+static struct lfsck_layout_seq *
+lfsck_layout_seq_lookup(struct lfsck_layout_slave_data *llsd, __u64 seq)
+{
+       struct lfsck_layout_seq *lls;
+
+       list_for_each_entry(lls, &llsd->llsd_seq_list, lls_list) {
+               if (lls->lls_seq == seq)
+                       return lls;
+
+               if (lls->lls_seq > seq)
+                       return NULL;
+       }
+
+       return NULL;
+}
+
+static void
+lfsck_layout_seq_insert(struct lfsck_layout_slave_data *llsd,
+                       struct lfsck_layout_seq *lls)
+{
+       struct lfsck_layout_seq *tmp;
+       struct list_head        *pos = &llsd->llsd_seq_list;
+
+       list_for_each_entry(tmp, &llsd->llsd_seq_list, lls_list) {
+               if (lls->lls_seq < tmp->lls_seq) {
+                       pos = &tmp->lls_list;
+                       break;
+               }
+       }
+       list_add_tail(&lls->lls_list, pos);
+}
+
+static int
+lfsck_layout_lastid_create(const struct lu_env *env,
+                          struct lfsck_instance *lfsck,
+                          struct dt_object *obj)
+{
+       struct lfsck_thread_info *info   = lfsck_env_info(env);
+       struct lu_attr           *la     = &info->lti_la;
+       struct dt_object_format  *dof    = &info->lti_dof;
+       struct lfsck_bookmark    *bk     = &lfsck->li_bookmark_ram;
+       struct dt_device         *dt     = lfsck->li_bottom;
+       struct thandle           *th;
+       __u64                     lastid = 0;
+       loff_t                    pos    = 0;
+       int                       rc;
+       ENTRY;
+
+       CDEBUG(D_LFSCK, "To create LAST_ID for <seq> "LPX64"\n",
+              fid_seq(lfsck_dto2fid(obj)));
+
+       if (bk->lb_param & LPF_DRYRUN)
+               return 0;
+
+       memset(la, 0, sizeof(*la));
+       la->la_mode = S_IFREG |  S_IRUGO | S_IWUSR;
+       la->la_valid = LA_MODE | LA_UID | LA_GID;
+       dof->dof_type = dt_mode_to_dft(S_IFREG);
+
+       th = dt_trans_create(env, dt);
+       if (IS_ERR(th))
+               RETURN(rc = PTR_ERR(th));
+
+       rc = dt_declare_create(env, obj, la, NULL, dof, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_declare_record_write(env, obj, sizeof(lastid), pos, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       rc = dt_trans_start_local(env, dt, th);
+       if (rc != 0)
+               GOTO(stop, rc);
+
+       dt_write_lock(env, obj, 0);
+       if (likely(!dt_object_exists(obj))) {
+               rc = dt_create(env, obj, la, NULL, dof, th);
+               if (rc == 0)
+                       rc = dt_record_write(env, obj,
+                               lfsck_buf_get(env, &lastid, sizeof(lastid)),
+                               &pos, th);
+       }
+       dt_write_unlock(env, obj);
+
+       GOTO(stop, rc);
+
+stop:
+       dt_trans_stop(env, dt, th);
+
+       return rc;
+}
+
+static int
+lfsck_layout_lastid_reload(const struct lu_env *env,
+                          struct lfsck_component *com,
+                          struct lfsck_layout_seq *lls)
+{
+       __u64   lastid;
+       loff_t  pos     = 0;
+       int     rc;
+
+       dt_read_lock(env, lls->lls_lastid_obj, 0);
+       rc = dt_record_read(env, lls->lls_lastid_obj,
+                           lfsck_buf_get(env, &lastid, sizeof(lastid)), &pos);
+       dt_read_unlock(env, lls->lls_lastid_obj);
+       if (unlikely(rc != 0))
+               return rc;
+
+       lastid = le64_to_cpu(lastid);
+       if (lastid < lls->lls_lastid_known) {
+               struct lfsck_instance   *lfsck  = com->lc_lfsck;
+               struct lfsck_layout     *lo     = com->lc_file_ram;
+
+               lls->lls_lastid = lls->lls_lastid_known;
+               lls->lls_dirty = 1;
+               if (!(lo->ll_flags & LF_CRASHED_LASTID)) {
+                       LASSERT(lfsck->li_out_notify != NULL);
+
+                       lfsck->li_out_notify(env, lfsck->li_out_notify_data,
+                                            LE_LASTID_REBUILDING);
+                       lo->ll_flags |= LF_CRASHED_LASTID;
+               }
+       } else if (lastid >= lls->lls_lastid) {
+               lls->lls_lastid = lastid;
+               lls->lls_dirty = 0;
+       }
+
+       return 0;
+}
+
+static int
+lfsck_layout_lastid_store(const struct lu_env *env,
+                         struct lfsck_component *com)
+{
+       struct lfsck_instance           *lfsck  = com->lc_lfsck;
+       struct lfsck_bookmark           *bk     = &lfsck->li_bookmark_ram;
+       struct dt_device                *dt     = lfsck->li_bottom;
+       struct lfsck_layout_slave_data  *llsd   = com->lc_data;
+       struct lfsck_layout_seq         *lls;
+       struct thandle                  *th;
+       __u64                            lastid;
+       int                              rc     = 0;
+       int                              rc1    = 0;
+
+       list_for_each_entry(lls, &llsd->llsd_seq_list, lls_list) {
+               loff_t pos = 0;
+
+               /* XXX: Add the code back if we really found related
+                *      inconsistent cases in the future. */
+#if 0
+               if (!lls->lls_dirty) {
+                       /* In OFD, before the pre-creation, the LAST_ID
+                        * file will be updated firstly, which may hide
+                        * some potential crashed cases. For example:
+                        *
+                        * The old obj1's ID is higher than old LAST_ID
+                        * but lower than the new LAST_ID, but the LFSCK
+                        * have not touch the obj1 until the OFD updated
+                        * the LAST_ID. So the LFSCK does not regard it
+                        * as crashed case. But when OFD does not create
+                        * successfully, it will set the LAST_ID as the
+                        * real created objects' ID, then LFSCK needs to
+                        * found related inconsistency. */
+                       rc = lfsck_layout_lastid_reload(env, com, lls);
+                       if (likely(!lls->lls_dirty))
+                               continue;
+               }
+#endif
+
+               CDEBUG(D_LFSCK, "To sync the LAST_ID for <seq> "LPX64
+                      " as <oid> "LPU64"\n", lls->lls_seq, lls->lls_lastid);
+
+               if (bk->lb_param & LPF_DRYRUN) {
+                       lls->lls_dirty = 0;
+                       continue;
+               }
+
+               th = dt_trans_create(env, dt);
+               if (IS_ERR(th)) {
+                       rc1 = PTR_ERR(th);
+                       CERROR("%s: (1) failed to store "LPX64": rc = %d\n",
+                              lfsck_lfsck2name(com->lc_lfsck),
+                              lls->lls_seq, rc1);
+                       continue;
+               }
+
+               rc = dt_declare_record_write(env, lls->lls_lastid_obj,
+                                            sizeof(lastid), pos, th);
+               if (rc != 0)
+                       goto stop;
+
+               rc = dt_trans_start_local(env, dt, th);
+               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,
+                                    sizeof(lastid)), &pos, th);
+               dt_write_unlock(env, lls->lls_lastid_obj);
+               if (rc == 0)
+                       lls->lls_dirty = 0;
+
+stop:
+               dt_trans_stop(env, dt, th);
+               if (rc != 0) {
+                       rc1 = rc;
+                       CERROR("%s: (2) failed to store "LPX64": rc = %d\n",
+                              lfsck_lfsck2name(com->lc_lfsck),
+                              lls->lls_seq, rc1);
+               }
+       }
+
+       return rc1;
+}
+
+static int
+lfsck_layout_lastid_load(const struct lu_env *env,
+                        struct lfsck_component *com,
+                        struct lfsck_layout_seq *lls)
+{
+       struct lfsck_instance   *lfsck  = com->lc_lfsck;
+       struct lfsck_layout     *lo     = com->lc_file_ram;
+       struct lu_fid           *fid    = &lfsck_env_info(env)->lti_fid;
+       struct dt_object        *obj;
+       loff_t                   pos    = 0;
+       int                      rc;
+       ENTRY;
+
+       lu_last_id_fid(fid, lls->lls_seq, lfsck_dev_idx(lfsck->li_bottom));
+       obj = dt_locate(env, lfsck->li_bottom, fid);
+       if (IS_ERR(obj))
+               RETURN(PTR_ERR(obj));
+
+       /* LAST_ID crashed, to be rebuilt */
+       if (!dt_object_exists(obj)) {
+               if (!(lo->ll_flags & LF_CRASHED_LASTID)) {
+                       LASSERT(lfsck->li_out_notify != NULL);
+
+                       lfsck->li_out_notify(env, lfsck->li_out_notify_data,
+                                            LE_LASTID_REBUILDING);
+                       lo->ll_flags |= LF_CRASHED_LASTID;
+
+                       if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_DELAY4) &&
+                           cfs_fail_val > 0) {
+                               struct l_wait_info lwi = LWI_TIMEOUT(
+                                               cfs_time_seconds(cfs_fail_val),
+                                               NULL, NULL);
+
+                               up_write(&com->lc_sem);
+                               l_wait_event(lfsck->li_thread.t_ctl_waitq,
+                                            !thread_is_running(&lfsck->li_thread),
+                                            &lwi);
+                               down_write(&com->lc_sem);
+                       }
+               }
+
+               rc = lfsck_layout_lastid_create(env, lfsck, obj);
+       } else {
+               dt_read_lock(env, obj, 0);
+               rc = dt_read(env, obj,
+                       lfsck_buf_get(env, &lls->lls_lastid, sizeof(__u64)),
+                       &pos);
+               dt_read_unlock(env, obj);
+               if (rc != 0 && rc != sizeof(__u64))
+                       GOTO(out, rc = (rc > 0 ? -EFAULT : rc));
+
+               if (rc == 0 && !(lo->ll_flags & LF_CRASHED_LASTID)) {
+                       LASSERT(lfsck->li_out_notify != NULL);
+
+                       lfsck->li_out_notify(env, lfsck->li_out_notify_data,
+                                            LE_LASTID_REBUILDING);
+                       lo->ll_flags |= LF_CRASHED_LASTID;
+               }
+
+               lls->lls_lastid = le64_to_cpu(lls->lls_lastid);
+               rc = 0;
+       }
+
+       GOTO(out, rc);
+
+out:
+       if (rc != 0)
+               lfsck_object_put(env, obj);
+       else
+               lls->lls_lastid_obj = obj;
+
+       return rc;
+}
+
+static int lfsck_layout_master_query_others(const struct lu_env *env,
+                                           struct lfsck_component *com)
+{
+       /* XXX: to be implemented. */
+
+       return 0;
+}
+
+static inline bool
+lfsck_layout_master_to_orphan(struct lfsck_layout_master_data *llmd)
+{
+       /* XXX: to be implemented. */
+
+       return 1;
+}
+
+static int lfsck_layout_master_notify_others(const struct lu_env *env,
+                                            struct lfsck_component *com,
+                                            struct lfsck_request *lr)
+{
+       /* XXX: to be implemented. */
+
+       return 0;
+}
+
+static int lfsck_layout_double_scan_result(const struct lu_env *env,
+                                          struct lfsck_component *com,
+                                          int rc)
+{
+       struct lfsck_instance   *lfsck = com->lc_lfsck;
+       struct lfsck_layout     *lo    = com->lc_file_ram;
+       struct lfsck_bookmark   *bk    = &lfsck->li_bookmark_ram;
+
+       down_write(&com->lc_sem);
+
+       lo->ll_run_time_phase2 += cfs_duration_sec(cfs_time_current() +
+                               HALF_SEC - lfsck->li_time_last_checkpoint);
+       lo->ll_time_last_checkpoint = cfs_time_current_sec();
+       lo->ll_objs_checked_phase2 += com->lc_new_checked;
+
+       if (rc > 0) {
+               com->lc_journal = 0;
+               if (lo->ll_flags & LF_INCOMPLETE)
+                       lo->ll_status = LS_PARTIAL;
+               else
+                       lo->ll_status = LS_COMPLETED;
+               if (!(bk->lb_param & LPF_DRYRUN))
+                       lo->ll_flags &= ~(LF_SCANNED_ONCE | LF_INCONSISTENT);
+               lo->ll_time_last_complete = lo->ll_time_last_checkpoint;
+               lo->ll_success_count++;
+       } else if (rc == 0) {
+               if (lfsck->li_paused)
+                       lo->ll_status = LS_PAUSED;
+               else
+                       lo->ll_status = LS_STOPPED;
+       } else {
+               lo->ll_status = LS_FAILED;
+       }
+
+       if (lo->ll_status != LS_PAUSED) {
+               spin_lock(&lfsck->li_lock);
+               list_del_init(&com->lc_link);
+               list_add_tail(&com->lc_link, &lfsck->li_list_idle);
+               spin_unlock(&lfsck->li_lock);
+       }
+
+       rc = lfsck_layout_store(env, com);
+
+       up_write(&com->lc_sem);
+
+       return rc;
+}
+
+static int lfsck_layout_assistant(void *args)
+{
+       struct lfsck_thread_args        *lta     = args;
+       struct lu_env                   *env     = &lta->lta_env;
+       struct lfsck_component          *com     = lta->lta_com;
+       struct lfsck_instance           *lfsck   = lta->lta_lfsck;
+       struct lfsck_bookmark           *bk      = &lfsck->li_bookmark_ram;
+       struct lfsck_position           *pos     = &com->lc_pos_start;
+       struct lfsck_thread_info        *info    = lfsck_env_info(env);
+       struct lfsck_request            *lr      = &info->lti_lr;
+       struct lfsck_layout_master_data *llmd    = com->lc_data;
+       struct ptlrpc_thread            *mthread = &lfsck->li_thread;
+       struct ptlrpc_thread            *athread = &llmd->llmd_thread;
+       struct lfsck_layout_req         *llr;
+       struct l_wait_info               lwi     = { 0 };
+       int                              rc      = 0;
+       int                              rc1     = 0;
+       ENTRY;
+
+       memset(lr, 0, sizeof(*lr));
+       lr->lr_event = LE_START;
+       lr->lr_index = lfsck_dev_idx(lfsck->li_bottom);
+       lr->lr_valid = LSV_SPEED_LIMIT | LSV_ERROR_HANDLE | LSV_DRYRUN |
+                      LSV_ASYNC_WINDOWS;
+       lr->lr_speed = bk->lb_speed_limit;
+       lr->lr_version = bk->lb_version;
+       lr->lr_active = LT_LAYOUT;
+       lr->lr_param = bk->lb_param;
+       lr->lr_async_windows = bk->lb_async_windows;
+       if (pos->lp_oit_cookie <= 1)
+               lr->lr_param |= LPF_RESET;
+
+       rc = lfsck_layout_master_notify_others(env, com, lr);
+       if (rc != 0) {
+               CERROR("%s: fail to notify others for layout start: rc = %d\n",
+                      lfsck_lfsck2name(lfsck), rc);
+               GOTO(fini, rc);
+       }
+
+       spin_lock(&llmd->llmd_lock);
+       thread_set_flags(athread, SVC_RUNNING);
+       spin_unlock(&llmd->llmd_lock);
+       wake_up_all(&mthread->t_ctl_waitq);
+
+       while (1) {
+               while (!list_empty(&llmd->llmd_req_list)) {
+                       bool wakeup = false;
+
+                       l_wait_event(athread->t_ctl_waitq,
+                                    bk->lb_async_windows == 0 ||
+                                    atomic_read(&llmd->llmd_rpcs_in_flight) <
+                                               bk->lb_async_windows ||
+                                    llmd->llmd_exit,
+                                    &lwi);
+
+                       if (unlikely(llmd->llmd_exit))
+                               GOTO(cleanup1, rc = llmd->llmd_post_result);
+
+                       /* XXX: To be extended in other patch.
+                        *
+                        * Compare the OST side attribute with local attribute,
+                        * and fix it if found inconsistency. */
+
+                       spin_lock(&llmd->llmd_lock);
+                       llr = list_entry(llmd->llmd_req_list.next,
+                                        struct lfsck_layout_req,
+                                        llr_list);
+                       list_del_init(&llr->llr_list);
+                       if (bk->lb_async_windows != 0 &&
+                           llmd->llmd_prefetched >= bk->lb_async_windows)
+                               wakeup = true;
+
+                       llmd->llmd_prefetched--;
+                       spin_unlock(&llmd->llmd_lock);
+                       if (wakeup)
+                               wake_up_all(&mthread->t_ctl_waitq);
+
+                       lfsck_layout_req_fini(env, llr);
+               }
+
+               /* Wakeup the master engine if it is waiting in checkpoint. */
+               if (atomic_read(&llmd->llmd_rpcs_in_flight) == 0)
+                       wake_up_all(&mthread->t_ctl_waitq);
+
+               l_wait_event(athread->t_ctl_waitq,
+                            !lfsck_layout_req_empty(llmd) ||
+                            llmd->llmd_exit ||
+                            llmd->llmd_to_post ||
+                            llmd->llmd_to_double_scan,
+                            &lwi);
+
+               if (unlikely(llmd->llmd_exit))
+                       GOTO(cleanup1, rc = llmd->llmd_post_result);
+
+               if (!list_empty(&llmd->llmd_req_list))
+                       continue;
+
+               if (llmd->llmd_to_post) {
+                       llmd->llmd_to_post = 0;
+                       LASSERT(llmd->llmd_post_result > 0);
+
+                       memset(lr, 0, sizeof(*lr));
+                       lr->lr_index = lfsck_dev_idx(lfsck->li_bottom);
+                       lr->lr_active = LT_LAYOUT;
+                       lr->lr_event = LE_PHASE1_DONE;
+                       lr->lr_status = llmd->llmd_post_result;
+                       rc = lfsck_layout_master_notify_others(env, com, lr);
+                       if (rc != 0)
+                               CERROR("%s: failed to notify others "
+                                      "for layout post: rc = %d\n",
+                                      lfsck_lfsck2name(lfsck), rc);
+
+                       /* Wakeup the master engine to go ahead. */
+                       wake_up_all(&mthread->t_ctl_waitq);
+               }
+
+               if (llmd->llmd_to_double_scan) {
+                       llmd->llmd_to_double_scan = 0;
+                       atomic_inc(&lfsck->li_double_scan_count);
+                       llmd->llmd_in_double_scan = 1;
+                       wake_up_all(&mthread->t_ctl_waitq);
+
+                       while (llmd->llmd_in_double_scan) {
+                               rc = lfsck_layout_master_query_others(env, com);
+                               if (lfsck_layout_master_to_orphan(llmd))
+                                       goto orphan;
+
+                               if (rc < 0)
+                                       GOTO(cleanup2, rc);
+
+                               /* Pull LFSCK status on related targets once
+                                * per 30 seconds if we are not notified. */
+                               lwi = LWI_TIMEOUT_INTERVAL(cfs_time_seconds(30),
+                                                          cfs_time_seconds(1),
+                                                          NULL, NULL);
+                               rc = l_wait_event(athread->t_ctl_waitq,
+                                       lfsck_layout_master_to_orphan(llmd) ||
+                                       llmd->llmd_exit ||
+                                       !thread_is_running(mthread),
+                                       &lwi);
+
+                               if (unlikely(llmd->llmd_exit ||
+                                            !thread_is_running(mthread)))
+                                       GOTO(cleanup2, rc = 0);
+
+                               if (rc == -ETIMEDOUT)
+                                       continue;
+
+                               if (rc < 0)
+                                       GOTO(cleanup2, rc);
+
+orphan:
+                               /* XXX: real double scan for ost orphans. */
+
+                               GOTO(cleanup2, rc = 1);
+                       }
+               }
+       }
+
+cleanup1:
+       /* Cleanup the unfinished requests. */
+       spin_lock(&llmd->llmd_lock);
+       while (!list_empty(&llmd->llmd_req_list)) {
+               llr = list_entry(llmd->llmd_req_list.next,
+                                struct lfsck_layout_req,
+                                llr_list);
+               list_del_init(&llr->llr_list);
+               llmd->llmd_prefetched--;
+               spin_unlock(&llmd->llmd_lock);
+               lfsck_layout_req_fini(env, llr);
+               spin_lock(&llmd->llmd_lock);
+       }
+       spin_unlock(&llmd->llmd_lock);
+
+       LASSERTF(llmd->llmd_prefetched == 0, "unmatched prefeteched objs %d\n",
+                llmd->llmd_prefetched);
+
+       l_wait_event(athread->t_ctl_waitq,
+                    atomic_read(&llmd->llmd_rpcs_in_flight) == 0,
+                    &lwi);
+
+cleanup2:
+       memset(lr, 0, sizeof(*lr));
+       lr->lr_index = lfsck_dev_idx(lfsck->li_bottom);
+       lr->lr_active = LT_LAYOUT;
+       if (rc > 0) {
+               lr->lr_event = LE_PHASE2_DONE;
+               lr->lr_status = rc;
+       } else if (rc == 0) {
+               lr->lr_event = LE_STOP;
+               if (lfsck->li_paused)
+                       lr->lr_status = LS_CO_PAUSED;
+               else
+                       lr->lr_status = LS_CO_STOPPED;
+       } else {
+               lr->lr_event = LE_STOP;
+               lr->lr_status = LS_CO_FAILED;
+       }
+
+       rc1 = lfsck_layout_master_notify_others(env, com, lr);
+       if (rc1 != 0) {
+               CERROR("%s: failed to notify others for layout quit: rc = %d\n",
+                      lfsck_lfsck2name(lfsck), rc1);
+               rc = rc1;
+       }
+
+       /* Under force exit case, some requests may be just freed without
+        * verification, those objects should be re-handled when next run.
+        * So not update the on-disk tracing file under such case. */
+       if (!llmd->llmd_exit)
+               rc1 = lfsck_layout_double_scan_result(env, com, rc);
+
+fini:
+       if (llmd->llmd_in_double_scan)
+               atomic_dec(&lfsck->li_double_scan_count);
+
+       spin_lock(&llmd->llmd_lock);
+       llmd->llmd_assistant_status = (rc1 != 0 ? rc1 : rc);
+       thread_set_flags(athread, SVC_STOPPED);
+       wake_up_all(&mthread->t_ctl_waitq);
+       spin_unlock(&llmd->llmd_lock);
+       lfsck_thread_args_fini(lta);
+
+       return rc;
+}
+
 /* layout APIs */
-/* XXX: Some to be implemented in other patch(es). */
 
 static int lfsck_layout_reset(const struct lu_env *env,
                              struct lfsck_component *com, bool init)
@@ -246,30 +947,224 @@ static int lfsck_layout_reset(const struct lu_env *env,
 static void lfsck_layout_fail(const struct lu_env *env,
                              struct lfsck_component *com, bool new_checked)
 {
+       struct lfsck_layout *lo = com->lc_file_ram;
+
+       down_write(&com->lc_sem);
+       if (new_checked)
+               com->lc_new_checked++;
+       lo->ll_objs_failed_phase1++;
+       if (lo->ll_pos_first_inconsistent == 0) {
+               struct lfsck_instance *lfsck = com->lc_lfsck;
+
+               lo->ll_pos_first_inconsistent =
+                       lfsck->li_obj_oit->do_index_ops->dio_it.store(env,
+                                                       lfsck->li_di_oit);
+       }
+       up_write(&com->lc_sem);
 }
 
-static int lfsck_layout_checkpoint(const struct lu_env *env,
-                                  struct lfsck_component *com, bool init)
+static int lfsck_layout_master_checkpoint(const struct lu_env *env,
+                                         struct lfsck_component *com, bool init)
 {
-       return 0;
+       struct lfsck_instance           *lfsck   = com->lc_lfsck;
+       struct lfsck_layout             *lo      = com->lc_file_ram;
+       struct lfsck_layout_master_data *llmd    = com->lc_data;
+       struct ptlrpc_thread            *mthread = &lfsck->li_thread;
+       struct ptlrpc_thread            *athread = &llmd->llmd_thread;
+       struct l_wait_info               lwi     = { 0 };
+       int                              rc;
+
+       if (com->lc_new_checked == 0 && !init)
+               return 0;
+
+       l_wait_event(mthread->t_ctl_waitq,
+                    (list_empty(&llmd->llmd_req_list) &&
+                     atomic_read(&llmd->llmd_rpcs_in_flight) == 0) ||
+                    !thread_is_running(mthread) ||
+                    thread_is_stopped(athread),
+                    &lwi);
+
+       if (!thread_is_running(mthread) || thread_is_stopped(athread))
+               return 0;
+
+       down_write(&com->lc_sem);
+       if (init) {
+               lo->ll_pos_latest_start = lfsck->li_pos_current.lp_oit_cookie;
+       } else {
+               lo->ll_pos_last_checkpoint =
+                                       lfsck->li_pos_current.lp_oit_cookie;
+               lo->ll_run_time_phase1 += cfs_duration_sec(cfs_time_current() +
+                               HALF_SEC - lfsck->li_time_last_checkpoint);
+               lo->ll_time_last_checkpoint = cfs_time_current_sec();
+               lo->ll_objs_checked_phase1 += com->lc_new_checked;
+               com->lc_new_checked = 0;
+       }
+
+       rc = lfsck_layout_store(env, com);
+       up_write(&com->lc_sem);
+
+       return rc;
 }
 
-static int lfsck_layout_master_prep(const struct lu_env *env,
-                                   struct lfsck_component *com)
+static int lfsck_layout_slave_checkpoint(const struct lu_env *env,
+                                        struct lfsck_component *com, bool init)
 {
-       return 0;
+       struct lfsck_instance   *lfsck = com->lc_lfsck;
+       struct lfsck_layout     *lo    = com->lc_file_ram;
+       int                      rc;
+
+       if (com->lc_new_checked == 0 && !init)
+               return 0;
+
+       down_write(&com->lc_sem);
+
+       if (init) {
+               lo->ll_pos_latest_start = lfsck->li_pos_current.lp_oit_cookie;
+       } else {
+               lo->ll_pos_last_checkpoint =
+                                       lfsck->li_pos_current.lp_oit_cookie;
+               lo->ll_run_time_phase1 += cfs_duration_sec(cfs_time_current() +
+                               HALF_SEC - lfsck->li_time_last_checkpoint);
+               lo->ll_time_last_checkpoint = cfs_time_current_sec();
+               lo->ll_objs_checked_phase1 += com->lc_new_checked;
+               com->lc_new_checked = 0;
+       }
+
+       rc = lfsck_layout_store(env, com);
+
+       up_write(&com->lc_sem);
+
+       return rc;
 }
 
 static int lfsck_layout_slave_prep(const struct lu_env *env,
                                   struct lfsck_component *com)
 {
+       struct lfsck_instance   *lfsck  = com->lc_lfsck;
+       struct lfsck_layout     *lo     = com->lc_file_ram;
+       struct lfsck_position   *pos    = &com->lc_pos_start;
+
+       /* XXX: For a new scanning, generate OST-objects
+        *      bitmap for orphan detection. */
+
+       fid_zero(&pos->lp_dir_parent);
+       pos->lp_dir_cookie = 0;
+       if (lo->ll_status == LS_COMPLETED ||
+           lo->ll_status == LS_PARTIAL) {
+               int rc;
+
+               rc = lfsck_layout_reset(env, com, false);
+               if (rc != 0)
+                       return rc;
+       }
+
+       down_write(&com->lc_sem);
+
+       lo->ll_time_latest_start = cfs_time_current_sec();
+
+       spin_lock(&lfsck->li_lock);
+       if (lo->ll_flags & LF_SCANNED_ONCE) {
+               if (!lfsck->li_drop_dryrun ||
+                   lo->ll_pos_first_inconsistent == 0) {
+                       lo->ll_status = LS_SCANNING_PHASE2;
+                       list_del_init(&com->lc_link);
+                       list_add_tail(&com->lc_link,
+                                     &lfsck->li_list_double_scan);
+                       pos->lp_oit_cookie = 0;
+               } else {
+                       int i;
+
+                       lo->ll_status = LS_SCANNING_PHASE1;
+                       lo->ll_run_time_phase1 = 0;
+                       lo->ll_run_time_phase2 = 0;
+                       lo->ll_objs_checked_phase1 = 0;
+                       lo->ll_objs_checked_phase2 = 0;
+                       lo->ll_objs_failed_phase1 = 0;
+                       lo->ll_objs_failed_phase2 = 0;
+                       for (i = 0; i < LLIT_MAX; i++)
+                               lo->ll_objs_repaired[i] = 0;
+
+                       pos->lp_oit_cookie = lo->ll_pos_first_inconsistent;
+               }
+       } else {
+               lo->ll_status = LS_SCANNING_PHASE1;
+               if (!lfsck->li_drop_dryrun ||
+                   lo->ll_pos_first_inconsistent == 0)
+                       pos->lp_oit_cookie = lo->ll_pos_last_checkpoint + 1;
+               else
+                       pos->lp_oit_cookie = lo->ll_pos_first_inconsistent;
+       }
+       spin_unlock(&lfsck->li_lock);
+
+       up_write(&com->lc_sem);
+
        return 0;
 }
 
+static int lfsck_layout_master_prep(const struct lu_env *env,
+                                   struct lfsck_component *com)
+{
+       struct lfsck_instance           *lfsck   = com->lc_lfsck;
+       struct lfsck_layout_master_data *llmd    = com->lc_data;
+       struct ptlrpc_thread            *mthread = &lfsck->li_thread;
+       struct ptlrpc_thread            *athread = &llmd->llmd_thread;
+       struct lfsck_thread_args        *lta;
+       long                             rc;
+       ENTRY;
+
+       rc = lfsck_layout_slave_prep(env, com);
+       if (rc != 0)
+               RETURN(rc);
+
+       llmd->llmd_assistant_status = 0;
+       llmd->llmd_post_result = 0;
+       llmd->llmd_to_post = 0;
+       llmd->llmd_to_double_scan = 0;
+       llmd->llmd_in_double_scan = 0;
+       llmd->llmd_exit = 0;
+       thread_set_flags(athread, 0);
+
+       lta = lfsck_thread_args_init(lfsck, com);
+       if (IS_ERR(lta))
+               RETURN(PTR_ERR(lta));
+
+       rc = PTR_ERR(kthread_run(lfsck_layout_assistant, lta, "lfsck_layout"));
+       if (IS_ERR_VALUE(rc)) {
+               CERROR("%s: Cannot start LFSCK layout assistant thread: "
+                      "rc = %ld\n", lfsck_lfsck2name(lfsck), rc);
+               lfsck_thread_args_fini(lta);
+       } else {
+               struct l_wait_info lwi = { 0 };
+
+               l_wait_event(mthread->t_ctl_waitq,
+                            thread_is_running(athread) ||
+                            thread_is_stopped(athread),
+                            &lwi);
+               if (unlikely(!thread_is_running(athread)))
+                       rc = llmd->llmd_assistant_status;
+               else
+                       rc = 0;
+       }
+
+       RETURN(rc);
+}
+
 static int lfsck_layout_master_exec_oit(const struct lu_env *env,
                                        struct lfsck_component *com,
                                        struct dt_object *obj)
 {
+       /* XXX: To be implemented in other patches.
+        *
+        * For the given object, read its layout EA locally. For each stripe,
+        * pre-fetch the OST-object's attribute and generate an structure
+        * lfsck_layout_req on the list ::llmd_req_list.
+        *
+        * For each request on the ::llmd_req_list, the lfsck_layout_assistant
+        * thread will compare the OST side attribute with local attribute,
+        * if inconsistent, then repair it.
+        *
+        * All above processing is async mode with pipeline. */
+
        return 0;
 }
 
@@ -277,7 +1172,84 @@ static int lfsck_layout_slave_exec_oit(const struct lu_env *env,
                                       struct lfsck_component *com,
                                       struct dt_object *obj)
 {
-       return 0;
+       struct lfsck_instance           *lfsck  = com->lc_lfsck;
+       struct lfsck_layout             *lo     = com->lc_file_ram;
+       const struct lu_fid             *fid    = lfsck_dto2fid(obj);
+       struct lfsck_layout_slave_data  *llsd   = com->lc_data;
+       struct lfsck_layout_seq         *lls;
+       __u64                            seq;
+       __u64                            oid;
+       int                              rc;
+       ENTRY;
+
+       /* XXX: Update OST-objects bitmap for orphan detection. */
+
+       LASSERT(llsd != NULL);
+
+       down_write(&com->lc_sem);
+       if (fid_is_idif(fid))
+               seq = 0;
+       else if (!fid_is_norm(fid) ||
+                !fid_is_for_ostobj(env, lfsck->li_next, obj, fid))
+               GOTO(unlock, rc = 0);
+       else
+               seq = fid_seq(fid);
+       com->lc_new_checked++;
+
+       lls = lfsck_layout_seq_lookup(llsd, seq);
+       if (lls == NULL) {
+               OBD_ALLOC_PTR(lls);
+               if (unlikely(lls == NULL))
+                       GOTO(unlock, rc = -ENOMEM);
+
+               INIT_LIST_HEAD(&lls->lls_list);
+               lls->lls_seq = seq;
+               rc = lfsck_layout_lastid_load(env, com, lls);
+               if (rc != 0) {
+                       lo->ll_objs_failed_phase1++;
+                       OBD_FREE_PTR(lls);
+                       GOTO(unlock, rc);
+               }
+
+               lfsck_layout_seq_insert(llsd, lls);
+       }
+
+       if (unlikely(fid_is_last_id(fid)))
+               GOTO(unlock, rc = 0);
+
+       oid = fid_oid(fid);
+       if (oid > lls->lls_lastid_known)
+               lls->lls_lastid_known = oid;
+
+       if (oid > lls->lls_lastid) {
+               if (!(lo->ll_flags & LF_CRASHED_LASTID)) {
+                       /* OFD may create new objects during LFSCK scanning. */
+                       rc = lfsck_layout_lastid_reload(env, com, lls);
+                       if (unlikely(rc != 0))
+                               CWARN("%s: failed to reload LAST_ID for "LPX64
+                                     ": rc = %d\n",
+                                     lfsck_lfsck2name(com->lc_lfsck),
+                                     lls->lls_seq, rc);
+                       if (oid <= lls->lls_lastid)
+                               GOTO(unlock, rc = 0);
+
+                       LASSERT(lfsck->li_out_notify != NULL);
+
+                       lfsck->li_out_notify(env, lfsck->li_out_notify_data,
+                                            LE_LASTID_REBUILDING);
+                       lo->ll_flags |= LF_CRASHED_LASTID;
+               }
+
+               lls->lls_lastid = oid;
+               lls->lls_dirty = 1;
+       }
+
+       GOTO(unlock, rc = 0);
+
+unlock:
+       up_write(&com->lc_sem);
+
+       return rc;
 }
 
 static int lfsck_layout_exec_dir(const struct lu_env *env,
@@ -292,56 +1264,448 @@ static int lfsck_layout_master_post(const struct lu_env *env,
                                    struct lfsck_component *com,
                                    int result, bool init)
 {
-       return 0;
+       struct lfsck_instance           *lfsck   = com->lc_lfsck;
+       struct lfsck_layout             *lo      = com->lc_file_ram;
+       struct lfsck_layout_master_data *llmd    = com->lc_data;
+       struct ptlrpc_thread            *mthread = &lfsck->li_thread;
+       struct ptlrpc_thread            *athread = &llmd->llmd_thread;
+       struct l_wait_info               lwi     = { 0 };
+       int                              rc;
+       ENTRY;
+
+
+       llmd->llmd_post_result = result;
+       llmd->llmd_to_post = 1;
+       if (llmd->llmd_post_result <= 0)
+               llmd->llmd_exit = 1;
+
+       wake_up_all(&athread->t_ctl_waitq);
+       l_wait_event(mthread->t_ctl_waitq,
+                    (result > 0 && list_empty(&llmd->llmd_req_list) &&
+                     atomic_read(&llmd->llmd_rpcs_in_flight) == 0) ||
+                    thread_is_stopped(athread),
+                    &lwi);
+
+       if (llmd->llmd_assistant_status < 0)
+               result = llmd->llmd_assistant_status;
+
+       down_write(&com->lc_sem);
+       spin_lock(&lfsck->li_lock);
+       /* When LFSCK failed, there may be some prefetched objects those are
+        * not been processed yet, we do not know the exactly position, then
+        * just restart from last check-point next time. */
+       if (!init && !llmd->llmd_exit)
+               lo->ll_pos_last_checkpoint =
+                                       lfsck->li_pos_current.lp_oit_cookie;
+
+       if (result > 0) {
+               lo->ll_status = LS_SCANNING_PHASE2;
+               lo->ll_flags |= LF_SCANNED_ONCE;
+               lo->ll_flags &= ~LF_UPGRADE;
+               list_del_init(&com->lc_link);
+               list_add_tail(&com->lc_link, &lfsck->li_list_double_scan);
+       } else if (result == 0) {
+               if (lfsck->li_paused) {
+                       lo->ll_status = LS_PAUSED;
+               } else {
+                       lo->ll_status = LS_STOPPED;
+                       list_del_init(&com->lc_link);
+                       list_add_tail(&com->lc_link, &lfsck->li_list_idle);
+               }
+       } else {
+               lo->ll_status = LS_FAILED;
+               list_del_init(&com->lc_link);
+               list_add_tail(&com->lc_link, &lfsck->li_list_idle);
+       }
+       spin_unlock(&lfsck->li_lock);
+
+       if (!init) {
+               lo->ll_run_time_phase1 += cfs_duration_sec(cfs_time_current() +
+                               HALF_SEC - lfsck->li_time_last_checkpoint);
+               lo->ll_time_last_checkpoint = cfs_time_current_sec();
+               lo->ll_objs_checked_phase1 += com->lc_new_checked;
+               com->lc_new_checked = 0;
+       }
+
+       rc = lfsck_layout_store(env, com);
+       up_write(&com->lc_sem);
+
+       RETURN(rc);
 }
 
 static int lfsck_layout_slave_post(const struct lu_env *env,
                                   struct lfsck_component *com,
                                   int result, bool init)
 {
-       return 0;
+       struct lfsck_instance   *lfsck = com->lc_lfsck;
+       struct lfsck_layout     *lo    = com->lc_file_ram;
+       int                      rc;
+       bool                     done  = false;
+
+       rc = lfsck_layout_lastid_store(env, com);
+       if (rc != 0)
+               result = rc;
+
+       LASSERT(lfsck->li_out_notify != NULL);
+
+       down_write(&com->lc_sem);
+
+       spin_lock(&lfsck->li_lock);
+       if (!init)
+               lo->ll_pos_last_checkpoint =
+                                       lfsck->li_pos_current.lp_oit_cookie;
+       if (result > 0) {
+               lo->ll_status = LS_SCANNING_PHASE2;
+               lo->ll_flags |= LF_SCANNED_ONCE;
+               if (lo->ll_flags & LF_CRASHED_LASTID) {
+                       done = true;
+                       lo->ll_flags &= ~LF_CRASHED_LASTID;
+               }
+               lo->ll_flags &= ~LF_UPGRADE;
+               list_del_init(&com->lc_link);
+               list_add_tail(&com->lc_link, &lfsck->li_list_double_scan);
+       } else if (result == 0) {
+               if (lfsck->li_paused) {
+                       lo->ll_status = LS_PAUSED;
+               } else {
+                       lo->ll_status = LS_STOPPED;
+                       list_del_init(&com->lc_link);
+                       list_add_tail(&com->lc_link, &lfsck->li_list_idle);
+               }
+       } else {
+               lo->ll_status = LS_FAILED;
+               list_del_init(&com->lc_link);
+               list_add_tail(&com->lc_link, &lfsck->li_list_idle);
+       }
+       spin_unlock(&lfsck->li_lock);
+
+       if (done)
+               lfsck->li_out_notify(env, lfsck->li_out_notify_data,
+                                    LE_LASTID_REBUILT);
+
+       if (!init) {
+               lo->ll_run_time_phase1 += cfs_duration_sec(cfs_time_current() +
+                               HALF_SEC - lfsck->li_time_last_checkpoint);
+               lo->ll_time_last_checkpoint = cfs_time_current_sec();
+               lo->ll_objs_checked_phase1 += com->lc_new_checked;
+               com->lc_new_checked = 0;
+       }
+
+       rc = lfsck_layout_store(env, com);
+
+       up_write(&com->lc_sem);
+
+       return rc;
 }
 
 static int lfsck_layout_dump(const struct lu_env *env,
                             struct lfsck_component *com, char *buf, int len)
 {
-       return 0;
+       struct lfsck_instance   *lfsck = com->lc_lfsck;
+       struct lfsck_bookmark   *bk    = &lfsck->li_bookmark_ram;
+       struct lfsck_layout     *lo    = com->lc_file_ram;
+       int                      save  = len;
+       int                      ret   = -ENOSPC;
+       int                      rc;
+
+       down_read(&com->lc_sem);
+       rc = snprintf(buf, len,
+                     "name: lfsck_layout\n"
+                     "magic: %#x\n"
+                     "version: %d\n"
+                     "status: %s\n",
+                     lo->ll_magic,
+                     bk->lb_version,
+                     lfsck_status2names(lo->ll_status));
+       if (rc <= 0)
+               goto out;
+
+       buf += rc;
+       len -= rc;
+       rc = lfsck_bits_dump(&buf, &len, lo->ll_flags, lfsck_flags_names,
+                            "flags");
+       if (rc < 0)
+               goto out;
+
+       rc = lfsck_bits_dump(&buf, &len, bk->lb_param, lfsck_param_names,
+                            "param");
+       if (rc < 0)
+               goto out;
+
+       rc = lfsck_time_dump(&buf, &len, lo->ll_time_last_complete,
+                            "time_since_last_completed");
+       if (rc < 0)
+               goto out;
+
+       rc = lfsck_time_dump(&buf, &len, lo->ll_time_latest_start,
+                            "time_since_latest_start");
+       if (rc < 0)
+               goto out;
+
+       rc = lfsck_time_dump(&buf, &len, lo->ll_time_last_checkpoint,
+                            "time_since_last_checkpoint");
+       if (rc < 0)
+               goto out;
+
+       rc = snprintf(buf, len,
+                     "latest_start_position: "LPU64"\n"
+                     "last_checkpoint_position: "LPU64"\n"
+                     "first_failure_position: "LPU64"\n",
+                     lo->ll_pos_latest_start,
+                     lo->ll_pos_last_checkpoint,
+                     lo->ll_pos_first_inconsistent);
+       if (rc <= 0)
+               goto out;
+
+       buf += rc;
+       len -= rc;
+
+       rc = snprintf(buf, len,
+                     "success_count: %u\n"
+                     "repaired_dangling: "LPU64"\n"
+                     "repaired_unmatched_pair: "LPU64"\n"
+                     "repaired_multiple_referenced: "LPU64"\n"
+                     "repaired_orphan: "LPU64"\n"
+                     "repaired_inconsistent_owner: "LPU64"\n"
+                     "repaired_others: "LPU64"\n"
+                     "skipped: "LPU64"\n"
+                     "failed_phase1: "LPU64"\n"
+                     "failed_phase2: "LPU64"\n",
+                     lo->ll_success_count,
+                     lo->ll_objs_repaired[LLIT_DANGLING - 1],
+                     lo->ll_objs_repaired[LLIT_UNMATCHED_PAIR - 1],
+                     lo->ll_objs_repaired[LLIT_MULTIPLE_REFERENCED - 1],
+                     lo->ll_objs_repaired[LLIT_ORPHAN - 1],
+                     lo->ll_objs_repaired[LLIT_INCONSISTENT_OWNER - 1],
+                     lo->ll_objs_repaired[LLIT_OTHERS - 1],
+                     lo->ll_objs_skipped,
+                     lo->ll_objs_failed_phase1,
+                     lo->ll_objs_failed_phase2);
+       if (rc <= 0)
+               goto out;
+
+       buf += rc;
+       len -= rc;
+
+       if (lo->ll_status == LS_SCANNING_PHASE1) {
+               __u64 pos;
+               const struct dt_it_ops *iops;
+               cfs_duration_t duration = cfs_time_current() -
+                                         lfsck->li_time_last_checkpoint;
+               __u64 checked = lo->ll_objs_checked_phase1 + com->lc_new_checked;
+               __u64 speed = checked;
+               __u64 new_checked = com->lc_new_checked * HZ;
+               __u32 rtime = lo->ll_run_time_phase1 +
+                             cfs_duration_sec(duration + HALF_SEC);
+
+               if (duration != 0)
+                       do_div(new_checked, duration);
+               if (rtime != 0)
+                       do_div(speed, rtime);
+               rc = snprintf(buf, len,
+                             "checked_phase1: "LPU64"\n"
+                             "checked_phase2: "LPU64"\n"
+                             "run_time_phase1: %u seconds\n"
+                             "run_time_phase2: %u seconds\n"
+                             "average_speed_phase1: "LPU64" items/sec\n"
+                             "average_speed_phase2: N/A\n"
+                             "real-time_speed_phase1: "LPU64" items/sec\n"
+                             "real-time_speed_phase2: N/A\n",
+                             checked,
+                             lo->ll_objs_checked_phase2,
+                             rtime,
+                             lo->ll_run_time_phase2,
+                             speed,
+                             new_checked);
+               if (rc <= 0)
+                       goto out;
+
+               buf += rc;
+               len -= rc;
+
+               LASSERT(lfsck->li_di_oit != NULL);
+
+               iops = &lfsck->li_obj_oit->do_index_ops->dio_it;
+
+               /* The low layer otable-based iteration position may NOT
+                * exactly match the layout-based directory traversal
+                * cookie. Generally, it is not a serious issue. But the
+                * caller should NOT make assumption on that. */
+               pos = iops->store(env, lfsck->li_di_oit);
+               if (!lfsck->li_current_oit_processed)
+                       pos--;
+               rc = snprintf(buf, len, "current_position: "LPU64"\n", pos);
+               if (rc <= 0)
+                       goto out;
+
+               buf += rc;
+               len -= rc;
+       } else {
+               /* XXX: LS_SCANNING_PHASE2 will be handled in the future. */
+               __u64 speed1 = lo->ll_objs_checked_phase1;
+               __u64 speed2 = lo->ll_objs_checked_phase2;
+
+               if (lo->ll_run_time_phase1 != 0)
+                       do_div(speed1, lo->ll_run_time_phase1);
+               if (lo->ll_run_time_phase2 != 0)
+                       do_div(speed2, lo->ll_run_time_phase2);
+               rc = snprintf(buf, len,
+                             "checked_phase1: "LPU64"\n"
+                             "checked_phase2: "LPU64"\n"
+                             "run_time_phase1: %u seconds\n"
+                             "run_time_phase2: %u seconds\n"
+                             "average_speed_phase1: "LPU64" items/sec\n"
+                             "average_speed_phase2: "LPU64" objs/sec\n"
+                             "real-time_speed_phase1: N/A\n"
+                             "real-time_speed_phase2: N/A\n"
+                             "current_position: N/A\n",
+                             lo->ll_objs_checked_phase1,
+                             lo->ll_objs_checked_phase2,
+                             lo->ll_run_time_phase1,
+                             lo->ll_run_time_phase2,
+                             speed1,
+                             speed2);
+               if (rc <= 0)
+                       goto out;
+
+               buf += rc;
+               len -= rc;
+       }
+       ret = save - len;
+
+out:
+       up_read(&com->lc_sem);
+
+       return ret;
 }
 
 static int lfsck_layout_master_double_scan(const struct lu_env *env,
                                           struct lfsck_component *com)
 {
+       struct lfsck_layout_master_data *llmd    = com->lc_data;
+       struct ptlrpc_thread            *mthread = &com->lc_lfsck->li_thread;
+       struct ptlrpc_thread            *athread = &llmd->llmd_thread;
+       struct lfsck_layout             *lo      = com->lc_file_ram;
+       struct l_wait_info               lwi     = { 0 };
+
+       if (unlikely(lo->ll_status != LS_SCANNING_PHASE2))
+               return 0;
+
+       llmd->llmd_to_double_scan = 1;
+       wake_up_all(&athread->t_ctl_waitq);
+       l_wait_event(mthread->t_ctl_waitq,
+                    llmd->llmd_in_double_scan ||
+                    thread_is_stopped(athread),
+                    &lwi);
+       if (llmd->llmd_assistant_status < 0)
+               return llmd->llmd_assistant_status;
+
        return 0;
 }
 
 static int lfsck_layout_slave_double_scan(const struct lu_env *env,
                                          struct lfsck_component *com)
 {
-       return 0;
+       struct lfsck_instance   *lfsck = com->lc_lfsck;
+       struct lfsck_layout     *lo    = com->lc_file_ram;
+       int                      rc    = 1;
+
+       if (unlikely(lo->ll_status != LS_SCANNING_PHASE2))
+               return 0;
+
+       atomic_inc(&lfsck->li_double_scan_count);
+
+       com->lc_new_checked = 0;
+       com->lc_new_scanned = 0;
+       com->lc_time_last_checkpoint = cfs_time_current();
+       com->lc_time_next_checkpoint = com->lc_time_last_checkpoint +
+                               cfs_time_seconds(LFSCK_CHECKPOINT_INTERVAL);
+
+       rc = lfsck_layout_double_scan_result(env, com, rc);
+
+       if (atomic_dec_and_test(&lfsck->li_double_scan_count))
+               wake_up_all(&lfsck->li_thread.t_ctl_waitq);
+
+       return rc;
+}
+
+static void lfsck_layout_master_data_release(const struct lu_env *env,
+                                            struct lfsck_component *com)
+{
+       struct lfsck_layout_master_data *llmd = com->lc_data;
+
+       LASSERT(llmd != NULL);
+       LASSERT(thread_is_init(&llmd->llmd_thread) ||
+               thread_is_stopped(&llmd->llmd_thread));
+       LASSERT(list_empty(&llmd->llmd_req_list));
+       LASSERT(atomic_read(&llmd->llmd_rpcs_in_flight) == 0);
+
+       com->lc_data = NULL;
+       OBD_FREE_PTR(llmd);
+}
+
+static void lfsck_layout_slave_data_release(const struct lu_env *env,
+                                           struct lfsck_component *com)
+{
+       struct lfsck_layout_slave_data  *llsd   = com->lc_data;
+       struct lfsck_layout_seq         *lls;
+       struct lfsck_layout_seq         *next;
+
+       LASSERT(llsd != NULL);
+
+       com->lc_data = NULL;
+
+       list_for_each_entry_safe(lls, next, &llsd->llsd_seq_list,
+                                    lls_list) {
+               list_del_init(&lls->lls_list);
+               lfsck_object_put(env, lls->lls_lastid_obj);
+               OBD_FREE_PTR(lls);
+       }
+
+       OBD_FREE_PTR(llsd);
+}
+
+static void lfsck_layout_master_quit(const struct lu_env *env,
+                                    struct lfsck_component *com)
+{
+       struct lfsck_layout_master_data *llmd    = com->lc_data;
+       struct ptlrpc_thread            *mthread = &com->lc_lfsck->li_thread;
+       struct ptlrpc_thread            *athread = &llmd->llmd_thread;
+       struct l_wait_info               lwi     = { 0 };
+
+       llmd->llmd_exit = 1;
+       wake_up_all(&athread->t_ctl_waitq);
+       l_wait_event(mthread->t_ctl_waitq,
+                    thread_is_init(athread) ||
+                    thread_is_stopped(athread),
+                    &lwi);
 }
 
 static struct lfsck_operations lfsck_layout_master_ops = {
        .lfsck_reset            = lfsck_layout_reset,
        .lfsck_fail             = lfsck_layout_fail,
-       .lfsck_checkpoint       = lfsck_layout_checkpoint,
+       .lfsck_checkpoint       = lfsck_layout_master_checkpoint,
        .lfsck_prep             = lfsck_layout_master_prep,
        .lfsck_exec_oit         = lfsck_layout_master_exec_oit,
        .lfsck_exec_dir         = lfsck_layout_exec_dir,
        .lfsck_post             = lfsck_layout_master_post,
        .lfsck_dump             = lfsck_layout_dump,
        .lfsck_double_scan      = lfsck_layout_master_double_scan,
+       .lfsck_data_release     = lfsck_layout_master_data_release,
+       .lfsck_quit             = lfsck_layout_master_quit,
 };
 
 static struct lfsck_operations lfsck_layout_slave_ops = {
        .lfsck_reset            = lfsck_layout_reset,
        .lfsck_fail             = lfsck_layout_fail,
-       .lfsck_checkpoint       = lfsck_layout_checkpoint,
+       .lfsck_checkpoint       = lfsck_layout_slave_checkpoint,
        .lfsck_prep             = lfsck_layout_slave_prep,
        .lfsck_exec_oit         = lfsck_layout_slave_exec_oit,
        .lfsck_exec_dir         = lfsck_layout_exec_dir,
        .lfsck_post             = lfsck_layout_slave_post,
        .lfsck_dump             = lfsck_layout_dump,
        .lfsck_double_scan      = lfsck_layout_slave_double_scan,
+       .lfsck_data_release     = lfsck_layout_slave_data_release,
 };
 
 int lfsck_layout_setup(const struct lu_env *env, struct lfsck_instance *lfsck)
@@ -363,10 +1727,30 @@ int lfsck_layout_setup(const struct lu_env *env, struct lfsck_instance *lfsck)
        atomic_set(&com->lc_ref, 1);
        com->lc_lfsck = lfsck;
        com->lc_type = LT_LAYOUT;
-       if (lfsck->li_master)
+       if (lfsck->li_master) {
+               struct lfsck_layout_master_data *llmd;
+
                com->lc_ops = &lfsck_layout_master_ops;
-       else
+               OBD_ALLOC_PTR(llmd);
+               if (llmd == NULL)
+                       GOTO(out, rc = -ENOMEM);
+
+               INIT_LIST_HEAD(&llmd->llmd_req_list);
+               spin_lock_init(&llmd->llmd_lock);
+               init_waitqueue_head(&llmd->llmd_thread.t_ctl_waitq);
+               atomic_set(&llmd->llmd_rpcs_in_flight, 0);
+               com->lc_data = llmd;
+       } else {
+               struct lfsck_layout_slave_data *llsd;
+
                com->lc_ops = &lfsck_layout_slave_ops;
+               OBD_ALLOC_PTR(llsd);
+               if (llsd == NULL)
+                       GOTO(out, rc = -ENOMEM);
+
+               INIT_LIST_HEAD(&llsd->llsd_seq_list);
+               com->lc_data = llsd;
+       }
        com->lc_file_size = sizeof(*lo);
        OBD_ALLOC(com->lc_file_ram, com->lc_file_size);
        if (com->lc_file_ram == NULL)
@@ -424,12 +1808,22 @@ int lfsck_layout_setup(const struct lu_env *env, struct lfsck_instance *lfsck)
                /* fall through */
        case LS_PAUSED:
        case LS_CRASHED:
+       case LS_CO_FAILED:
+       case LS_CO_STOPPED:
+       case LS_CO_PAUSED:
                spin_lock(&lfsck->li_lock);
                list_add_tail(&com->lc_link, &lfsck->li_list_scan);
                spin_unlock(&lfsck->li_lock);
                break;
        }
 
+       if (lo->ll_flags & LF_CRASHED_LASTID) {
+               LASSERT(lfsck->li_out_notify != NULL);
+
+               lfsck->li_out_notify(env, lfsck->li_out_notify_data,
+                                    LE_LASTID_REBUILDING);
+       }
+
        GOTO(out, rc = 0);
 
 out: