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LU-11757 lod: use calculated stripe count
[fs/lustre-release.git] / lustre / lod / lod_object.c
index cedac80..d7fdad2 100644 (file)
@@ -23,7 +23,7 @@
  * Copyright  2009 Sun Microsystems, Inc. All rights reserved
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, 2016, Intel Corporation.
+ * Copyright (c) 2012, 2017, Intel Corporation.
  */
 /*
  * lustre/lod/lod_object.c
@@ -40,6 +40,8 @@
 
 #define DEBUG_SUBSYSTEM S_MDS
 
+#include <linux/random.h>
+
 #include <obd.h>
 #include <obd_class.h>
 #include <obd_support.h>
@@ -96,9 +98,9 @@ static int lod_declare_insert(const struct lu_env *env, struct dt_object *dt,
  */
 static int lod_insert(const struct lu_env *env, struct dt_object *dt,
                      const struct dt_rec *rec, const struct dt_key *key,
-                     struct thandle *th, int ign)
+                     struct thandle *th)
 {
-       return lod_sub_insert(env, dt_object_child(dt), rec, key, th, ign);
+       return lod_sub_insert(env, dt_object_child(dt), rec, key, th);
 }
 
 /**
@@ -774,14 +776,9 @@ int lod_load_lmv_shards(const struct lu_env *env, struct lod_object *lo,
        int                      rc;
        ENTRY;
 
-       /* If it is not a striped directory, then load nothing. */
        if (magic != LMV_MAGIC_V1)
                RETURN(0);
 
-       /* If it is in migration (or failure), then load nothing. */
-       if (le32_to_cpu(lmv1->lmv_hash_type) & LMV_HASH_FLAG_MIGRATION)
-               RETURN(0);
-
        stripes = le32_to_cpu(lmv1->lmv_stripe_count);
        if (stripes < 1)
                RETURN(0);
@@ -947,7 +944,7 @@ static int lod_index_try(const struct lu_env *env, struct dt_object *dt,
        LASSERT(next->do_ops);
        LASSERT(next->do_ops->do_index_try);
 
-       rc = lod_load_striping_locked(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc != 0)
                RETURN(rc);
 
@@ -1046,8 +1043,20 @@ static int lod_attr_get(const struct lu_env *env,
        return dt_attr_get(env, dt_object_child(dt), attr);
 }
 
+static inline void lod_adjust_stripe_info(struct lod_layout_component *comp,
+                                         struct lov_desc *desc)
+{
+       if (comp->llc_pattern != LOV_PATTERN_MDT) {
+               if (!comp->llc_stripe_count)
+                       comp->llc_stripe_count =
+                               desc->ld_default_stripe_count;
+       }
+       if (comp->llc_stripe_size <= 0)
+               comp->llc_stripe_size = desc->ld_default_stripe_size;
+}
+
 int lod_obj_for_each_stripe(const struct lu_env *env, struct lod_object *lo,
-                           struct thandle *th, lod_obj_stripe_cb_t cb,
+                           struct thandle *th,
                            struct lod_obj_stripe_cb_data *data)
 {
        struct lod_layout_component *lod_comp;
@@ -1061,13 +1070,35 @@ int lod_obj_for_each_stripe(const struct lu_env *env, struct lod_object *lo,
                if (lod_comp->llc_stripe == NULL)
                        continue;
 
+               /* has stripe but not inited yet, this component has been
+                * declared to be created, but hasn't created yet.
+                */
+               if (!lod_comp_inited(lod_comp))
+                       continue;
+
+               if (data->locd_comp_skip_cb &&
+                   data->locd_comp_skip_cb(env, lo, i, data))
+                       continue;
+
+               if (data->locd_comp_cb) {
+                       rc = data->locd_comp_cb(env, lo, i, data);
+                       if (rc)
+                               RETURN(rc);
+               }
+
+               /* could used just to do sth about component, not each
+                * stripes
+                */
+               if (!data->locd_stripe_cb)
+                       continue;
+
                LASSERT(lod_comp->llc_stripe_count > 0);
                for (j = 0; j < lod_comp->llc_stripe_count; j++) {
                        struct dt_object *dt = lod_comp->llc_stripe[j];
 
                        if (dt == NULL)
                                continue;
-                       rc = cb(env, lo, dt, th, j, data);
+                       rc = data->locd_stripe_cb(env, lo, dt, th, i, j, data);
                        if (rc != 0)
                                RETURN(rc);
                }
@@ -1075,14 +1106,73 @@ int lod_obj_for_each_stripe(const struct lu_env *env, struct lod_object *lo,
        RETURN(0);
 }
 
+static bool lod_obj_attr_set_comp_skip_cb(const struct lu_env *env,
+               struct lod_object *lo, int comp_idx,
+               struct lod_obj_stripe_cb_data *data)
+{
+       struct lod_layout_component *lod_comp = &lo->ldo_comp_entries[comp_idx];
+       bool skipped = false;
+
+       if (!(data->locd_attr->la_valid & LA_LAYOUT_VERSION))
+               return skipped;
+
+       switch (lo->ldo_flr_state) {
+       case LCM_FL_WRITE_PENDING: {
+               int i;
+
+               /* skip stale components */
+               if (lod_comp->llc_flags & LCME_FL_STALE) {
+                       skipped = true;
+                       break;
+               }
+
+               /* skip valid and overlapping components, therefore any
+                * attempts to write overlapped components will never succeed
+                * because client will get EINPROGRESS. */
+               for (i = 0; i < lo->ldo_comp_cnt; i++) {
+                       if (i == comp_idx)
+                               continue;
+
+                       if (lo->ldo_comp_entries[i].llc_flags & LCME_FL_STALE)
+                               continue;
+
+                       if (lu_extent_is_overlapped(&lod_comp->llc_extent,
+                                       &lo->ldo_comp_entries[i].llc_extent)) {
+                               skipped = true;
+                               break;
+                       }
+               }
+               break;
+       }
+       default:
+               LASSERTF(0, "impossible: %d\n", lo->ldo_flr_state);
+       case LCM_FL_SYNC_PENDING:
+               break;
+       }
+
+       CDEBUG(D_LAYOUT, DFID": %s to set component %x to version: %u\n",
+              PFID(lu_object_fid(&lo->ldo_obj.do_lu)),
+              skipped ? "skipped" : "chose", lod_comp->llc_id,
+              data->locd_attr->la_layout_version);
+
+       return skipped;
+}
+
 static inline int
 lod_obj_stripe_attr_set_cb(const struct lu_env *env, struct lod_object *lo,
                           struct dt_object *dt, struct thandle *th,
-                          int stripe_idx, struct lod_obj_stripe_cb_data *data)
+                          int comp_idx, int stripe_idx,
+                          struct lod_obj_stripe_cb_data *data)
 {
        if (data->locd_declare)
                return lod_sub_declare_attr_set(env, dt, data->locd_attr, th);
 
+       if (data->locd_attr->la_valid & LA_LAYOUT_VERSION) {
+               CDEBUG(D_LAYOUT, DFID": set layout version: %u, comp_idx: %d\n",
+                      PFID(lu_object_fid(&dt->do_lu)),
+                      data->locd_attr->la_layout_version, comp_idx);
+       }
+
        return lod_sub_attr_set(env, dt, data->locd_attr, th);
 }
 
@@ -1120,7 +1210,7 @@ static int lod_declare_attr_set(const struct lu_env *env,
         * speed up rename().
         */
        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr)) {
-               if (!(attr->la_valid & (LA_UID | LA_GID | LA_PROJID)))
+               if (!(attr->la_valid & LA_REMOTE_ATTR_SET))
                        RETURN(rc);
 
                if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_OWNER))
@@ -1136,7 +1226,7 @@ static int lod_declare_attr_set(const struct lu_env *env,
         * is being initialized as we don't need this information till
         * few specific cases like destroy, chown
         */
-       rc = lod_load_striping(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc)
                RETURN(rc);
 
@@ -1157,12 +1247,12 @@ static int lod_declare_attr_set(const struct lu_env *env,
                                RETURN(rc);
                }
        } else {
-               struct lod_obj_stripe_cb_data data;
+               struct lod_obj_stripe_cb_data data = { { 0 } };
 
                data.locd_attr = attr;
                data.locd_declare = true;
-               rc = lod_obj_for_each_stripe(env, lo, th,
-                               lod_obj_stripe_attr_set_cb, &data);
+               data.locd_stripe_cb = lod_obj_stripe_attr_set_cb;
+               rc = lod_obj_for_each_stripe(env, lo, th, &data);
        }
 
        if (rc)
@@ -1217,7 +1307,7 @@ static int lod_attr_set(const struct lu_env *env,
                RETURN(rc);
 
        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr)) {
-               if (!(attr->la_valid & (LA_UID | LA_GID | LA_PROJID)))
+               if (!(attr->la_valid & LA_REMOTE_ATTR_SET))
                        RETURN(rc);
 
                if (OBD_FAIL_CHECK(OBD_FAIL_LFSCK_BAD_OWNER))
@@ -1229,6 +1319,14 @@ static int lod_attr_set(const struct lu_env *env,
                        RETURN(rc);
        }
 
+       /* FIXME: a tricky case in the code path of mdd_layout_change():
+        * the in-memory striping information has been freed in lod_xattr_set()
+        * due to layout change. It has to load stripe here again. It only
+        * changes flags of layout so declare_attr_set() is still accurate */
+       rc = lod_striping_load(env, lo);
+       if (rc)
+               RETURN(rc);
+
        if (!lod_obj_is_striped(dt))
                RETURN(0);
 
@@ -1249,12 +1347,13 @@ static int lod_attr_set(const struct lu_env *env,
                                break;
                }
        } else {
-               struct lod_obj_stripe_cb_data data;
+               struct lod_obj_stripe_cb_data data = { { 0 } };
 
                data.locd_attr = attr;
                data.locd_declare = false;
-               rc = lod_obj_for_each_stripe(env, lo, th,
-                               lod_obj_stripe_attr_set_cb, &data);
+               data.locd_comp_skip_cb = lod_obj_attr_set_comp_skip_cb;
+               data.locd_stripe_cb = lod_obj_stripe_attr_set_cb;
+               rc = lod_obj_for_each_stripe(env, lo, th, &data);
        }
 
        if (rc)
@@ -1511,9 +1610,15 @@ static int lod_prep_lmv_md(const struct lu_env *env, struct dt_object *dt,
        }
 
        lmm1 = (struct lmv_mds_md_v1 *)info->lti_ea_store;
+       memset(lmm1, 0, sizeof(*lmm1));
        lmm1->lmv_magic = cpu_to_le32(LMV_MAGIC);
        lmm1->lmv_stripe_count = cpu_to_le32(stripe_count);
        lmm1->lmv_hash_type = cpu_to_le32(lo->ldo_dir_hash_type);
+       if (lo->ldo_dir_hash_type & LMV_HASH_FLAG_MIGRATION) {
+               lmm1->lmv_migrate_hash = cpu_to_le32(lo->ldo_dir_migrate_hash);
+               lmm1->lmv_migrate_offset =
+                       cpu_to_le32(lo->ldo_dir_migrate_offset);
+       }
        rc = lod_fld_lookup(env, lod, lu_object_fid(&dt->do_lu),
                            &mdtidx, &type);
        if (rc != 0)
@@ -1555,8 +1660,7 @@ int lod_parse_dir_striping(const struct lu_env *env, struct lod_object *lo,
        int                     rc = 0;
        ENTRY;
 
-       if (le32_to_cpu(lmv1->lmv_hash_type) & LMV_HASH_FLAG_MIGRATION)
-               RETURN(0);
+       LASSERT(mutex_is_locked(&lo->ldo_layout_mutex));
 
        if (le32_to_cpu(lmv1->lmv_magic) == LMV_MAGIC_STRIPE) {
                lo->ldo_dir_slave_stripe = 1;
@@ -1613,7 +1717,7 @@ out:
        lo->ldo_dir_stripe_count = le32_to_cpu(lmv1->lmv_stripe_count);
        lo->ldo_dir_stripes_allocated = le32_to_cpu(lmv1->lmv_stripe_count);
        if (rc != 0)
-               lod_object_free_striping(env, lo);
+               lod_striping_free_nolock(env, lo);
 
        RETURN(rc);
 }
@@ -1771,6 +1875,7 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
                                      struct dt_object_format *dof,
                                      struct thandle *th)
 {
+       struct lod_thread_info  *info = lod_env_info(env);
        struct lod_device       *lod = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_tgt_descs    *ltd = &lod->lod_mdt_descs;
        struct lod_object       *lo = lod_dt_obj(dt);
@@ -1781,13 +1886,14 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
        int                     rc = 0;
        __u32                   i;
        __u32                   j;
+       bool                    is_specific = false;
        ENTRY;
 
        /* The lum has been verifed in lod_verify_md_striping */
-       LASSERT(le32_to_cpu(lum->lum_magic) == LMV_USER_MAGIC);
-       LASSERT(le32_to_cpu(lum->lum_stripe_count) > 0);
+       LASSERT(le32_to_cpu(lum->lum_magic) == LMV_USER_MAGIC ||
+               le32_to_cpu(lum->lum_magic) == LMV_USER_MAGIC_SPECIFIC);
 
-       stripe_count = le32_to_cpu(lum->lum_stripe_count);
+       stripe_count = lo->ldo_dir_stripe_count;
 
        OBD_ALLOC(idx_array, sizeof(idx_array[0]) * stripe_count);
        if (idx_array == NULL)
@@ -1800,6 +1906,12 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
        /* Start index must be the master MDT */
        master_index = lu_site2seq(lod2lu_dev(lod)->ld_site)->ss_node_id;
        idx_array[0] = master_index;
+       if (le32_to_cpu(lum->lum_magic) == LMV_USER_MAGIC_SPECIFIC) {
+               is_specific = true;
+               for (i = 1; i < stripe_count; i++)
+                       idx_array[i] = le32_to_cpu(lum->lum_objects[i].lum_mds);
+       }
+
        for (i = 0; i < stripe_count; i++) {
                struct lod_tgt_desc     *tgt = NULL;
                struct dt_object        *dto;
@@ -1818,7 +1930,8 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
                        CDEBUG(D_INFO, "try idx %d, mdt cnt %u, allocated %u\n",
                               idx, lod->lod_remote_mdt_count + 1, i);
 
-                       if (likely(!OBD_FAIL_CHECK(OBD_FAIL_LARGE_STRIPE))) {
+                       if (likely(!is_specific &&
+                                  !OBD_FAIL_CHECK(OBD_FAIL_LARGE_STRIPE))) {
                                /* check whether the idx already exists
                                 * in current allocated array */
                                for (k = 0; k < i; k++) {
@@ -1854,7 +1967,7 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
                                continue;
 
                        tgt_dt = tgt->ltd_tgt;
-                       rc = dt_statfs(env, tgt_dt, NULL);
+                       rc = dt_statfs(env, tgt_dt, &info->lti_osfs);
                        if (rc) {
                                /* this OSP doesn't feel well */
                                rc = 0;
@@ -1881,9 +1994,17 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
                       idx, i, PFID(&fid));
                idx_array[i] = idx;
                /* Set the start index for next stripe allocation */
-               if (i < stripe_count - 1)
+               if (!is_specific && i < stripe_count - 1) {
+                       /*
+                        * for large dir test, put all other slaves on one
+                        * remote MDT, otherwise we may save too many local
+                        * slave locks which will exceed RS_MAX_LOCKS.
+                        */
+                       if (unlikely(OBD_FAIL_CHECK(OBD_FAIL_LARGE_STRIPE)))
+                               idx = master_index;
                        idx_array[i + 1] = (idx + 1) %
                                           (lod->lod_remote_mdt_count + 1);
+               }
                /* tgt_dt and fid must be ready after search avaible OSP
                 * in the above loop */
                LASSERT(tgt_dt != NULL);
@@ -1901,6 +2022,8 @@ static int lod_prep_md_striped_create(const struct lu_env *env,
        lo->ldo_stripe = stripe;
        lo->ldo_dir_stripe_count = i;
        lo->ldo_dir_stripes_allocated = stripe_count;
+       smp_mb();
+       lo->ldo_dir_stripe_loaded = 1;
 
        if (lo->ldo_dir_stripe_count == 0)
                GOTO(out_put, rc = -ENOSPC);
@@ -1953,31 +2076,25 @@ static int lod_declare_xattr_set_lmv(const struct lu_env *env,
                                     struct thandle *th)
 {
        struct lod_object       *lo = lod_dt_obj(dt);
-       struct lod_device       *lod = lu2lod_dev(dt->do_lu.lo_dev);
-       struct lmv_user_md_v1   *lum;
+       struct lmv_user_md_v1   *lum = lum_buf->lb_buf;
        int                     rc;
        ENTRY;
 
-       lum = lum_buf->lb_buf;
        LASSERT(lum != NULL);
 
        CDEBUG(D_INFO, "lum magic = %x count = %u offset = %d\n",
               le32_to_cpu(lum->lum_magic), le32_to_cpu(lum->lum_stripe_count),
               (int)le32_to_cpu(lum->lum_stripe_offset));
 
-       if (le32_to_cpu(lum->lum_stripe_count) == 0)
+       if (lo->ldo_dir_stripe_count == 0)
                GOTO(out, rc = 0);
 
-       rc = lod_verify_md_striping(lod, lum);
-       if (rc != 0)
-               GOTO(out, rc);
-
        /* prepare dir striped objects */
        rc = lod_prep_md_striped_create(env, dt, attr, lum, dof, th);
        if (rc != 0) {
                /* failed to create striping, let's reset
                 * config so that others don't get confused */
-               lod_object_free_striping(env, lo);
+               lod_striping_free(env, lo);
                GOTO(out, rc);
        }
 out:
@@ -1985,6 +2102,284 @@ out:
 }
 
 /**
+ * Append source stripes after target stripes for migrating directory. NB, we
+ * only need to declare this, the append is done inside lod_xattr_set_lmv().
+ *
+ * \param[in] env      execution environment
+ * \param[in] dt       target object
+ * \param[in] buf      LMV buf which contains source stripe fids
+ * \param[in] th       transaction handle
+ *
+ * \retval             0 on success
+ * \retval             negative if failed
+ */
+static int lod_dir_declare_layout_add(const struct lu_env *env,
+                                     struct dt_object *dt,
+                                     const struct lu_buf *buf,
+                                     struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lod_device *lod = lu2lod_dev(dt->do_lu.lo_dev);
+       struct lod_tgt_descs *ltd = &lod->lod_mdt_descs;
+       struct lod_object *lo = lod_dt_obj(dt);
+       struct dt_object *next = dt_object_child(dt);
+       struct dt_object_format *dof = &info->lti_format;
+       struct lmv_mds_md_v1 *lmv = buf->lb_buf;
+       struct dt_object **stripe;
+       __u32 stripe_count = le32_to_cpu(lmv->lmv_stripe_count);
+       struct lu_fid *fid = &info->lti_fid;
+       struct lod_tgt_desc *tgt;
+       struct dt_object *dto;
+       struct dt_device *tgt_dt;
+       int type = LU_SEQ_RANGE_ANY;
+       struct dt_insert_rec *rec = &info->lti_dt_rec;
+       char *stripe_name = info->lti_key;
+       struct lu_name *sname;
+       struct linkea_data ldata = { NULL };
+       struct lu_buf linkea_buf;
+       __u32 idx;
+       int i;
+       int rc;
+
+       ENTRY;
+
+       if (le32_to_cpu(lmv->lmv_magic) != LMV_MAGIC_V1)
+               RETURN(-EINVAL);
+
+       if (stripe_count == 0)
+               RETURN(-EINVAL);
+
+       dof->dof_type = DFT_DIR;
+
+       OBD_ALLOC(stripe,
+                 sizeof(*stripe) * (lo->ldo_dir_stripe_count + stripe_count));
+       if (stripe == NULL)
+               RETURN(-ENOMEM);
+
+       for (i = 0; i < lo->ldo_dir_stripe_count; i++)
+               stripe[i] = lo->ldo_stripe[i];
+
+       for (i = 0; i < stripe_count; i++) {
+               fid_le_to_cpu(fid,
+                       &lmv->lmv_stripe_fids[i]);
+               if (!fid_is_sane(fid))
+                       GOTO(out, rc = -ESTALE);
+
+               rc = lod_fld_lookup(env, lod, fid, &idx, &type);
+               if (rc)
+                       GOTO(out, rc);
+
+               if (idx == lod2lu_dev(lod)->ld_site->ld_seq_site->ss_node_id) {
+                       tgt_dt = lod->lod_child;
+               } else {
+                       tgt = LTD_TGT(ltd, idx);
+                       if (tgt == NULL)
+                               GOTO(out, rc = -ESTALE);
+                       tgt_dt = tgt->ltd_tgt;
+               }
+
+               dto = dt_locate_at(env, tgt_dt, fid,
+                                 lo->ldo_obj.do_lu.lo_dev->ld_site->ls_top_dev,
+                                 NULL);
+               if (IS_ERR(dto))
+                       GOTO(out, rc = PTR_ERR(dto));
+
+               stripe[i + lo->ldo_dir_stripe_count] = dto;
+
+               if (!dt_try_as_dir(env, dto))
+                       GOTO(out, rc = -ENOTDIR);
+
+               rc = lod_sub_declare_ref_add(env, dto, th);
+               if (rc)
+                       GOTO(out, rc);
+
+               rc = lod_sub_declare_insert(env, dto,
+                                           (const struct dt_rec *)rec,
+                                           (const struct dt_key *)dot, th);
+               if (rc)
+                       GOTO(out, rc);
+
+               rc = lod_sub_declare_insert(env, dto,
+                                           (const struct dt_rec *)rec,
+                                           (const struct dt_key *)dotdot, th);
+               if (rc)
+                       GOTO(out, rc);
+
+               rc = lod_sub_declare_xattr_set(env, dto, buf,
+                                               XATTR_NAME_LMV, 0, th);
+               if (rc)
+                       GOTO(out, rc);
+
+               snprintf(stripe_name, sizeof(info->lti_key), DFID":%u",
+                        PFID(lu_object_fid(&dto->do_lu)),
+                        i + lo->ldo_dir_stripe_count);
+
+               sname = lod_name_get(env, stripe_name, strlen(stripe_name));
+               rc = linkea_links_new(&ldata, &info->lti_linkea_buf,
+                                     sname, lu_object_fid(&dt->do_lu));
+               if (rc)
+                       GOTO(out, rc);
+
+               linkea_buf.lb_buf = ldata.ld_buf->lb_buf;
+               linkea_buf.lb_len = ldata.ld_leh->leh_len;
+               rc = lod_sub_declare_xattr_set(env, dto, &linkea_buf,
+                                              XATTR_NAME_LINK, 0, th);
+               if (rc)
+                       GOTO(out, rc);
+
+               rc = lod_sub_declare_insert(env, next,
+                                           (const struct dt_rec *)rec,
+                                           (const struct dt_key *)stripe_name,
+                                           th);
+               if (rc)
+                       GOTO(out, rc);
+
+               rc = lod_sub_declare_ref_add(env, next, th);
+               if (rc)
+                       GOTO(out, rc);
+       }
+
+       if (lo->ldo_stripe)
+               OBD_FREE(lo->ldo_stripe,
+                        sizeof(*stripe) * lo->ldo_dir_stripes_allocated);
+       lo->ldo_stripe = stripe;
+       lo->ldo_dir_migrate_offset = lo->ldo_dir_stripe_count;
+       lo->ldo_dir_migrate_hash = le32_to_cpu(lmv->lmv_hash_type);
+       lo->ldo_dir_stripe_count += stripe_count;
+       lo->ldo_dir_stripes_allocated += stripe_count;
+       lo->ldo_dir_hash_type |= LMV_HASH_FLAG_MIGRATION;
+
+       RETURN(0);
+out:
+       i = lo->ldo_dir_stripe_count;
+       while (i < lo->ldo_dir_stripe_count + stripe_count && stripe[i])
+               dt_object_put(env, stripe[i++]);
+
+       OBD_FREE(stripe,
+                sizeof(*stripe) * (stripe_count + lo->ldo_dir_stripe_count));
+       RETURN(rc);
+}
+
+static int lod_dir_declare_layout_delete(const struct lu_env *env,
+                                        struct dt_object *dt,
+                                        const struct lu_buf *buf,
+                                        struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lod_object *lo = lod_dt_obj(dt);
+       struct dt_object *next = dt_object_child(dt);
+       struct lmv_user_md *lmu = buf->lb_buf;
+       __u32 final_stripe_count;
+       char *stripe_name = info->lti_key;
+       struct dt_object *dto;
+       int i;
+       int rc = 0;
+
+       if (!lmu)
+               return -EINVAL;
+
+       final_stripe_count = le32_to_cpu(lmu->lum_stripe_count);
+       if (final_stripe_count >= lo->ldo_dir_stripe_count)
+               return -EINVAL;
+
+       for (i = final_stripe_count; i < lo->ldo_dir_stripe_count; i++) {
+               dto = lo->ldo_stripe[i];
+               LASSERT(dto);
+
+               if (!dt_try_as_dir(env, dto))
+                       return -ENOTDIR;
+
+               rc = lod_sub_declare_delete(env, dto,
+                                           (const struct dt_key *)dot, th);
+               if (rc)
+                       return rc;
+
+               rc = lod_sub_declare_ref_del(env, dto, th);
+               if (rc)
+                       return rc;
+
+               rc = lod_sub_declare_delete(env, dto,
+                                       (const struct dt_key *)dotdot, th);
+               if (rc)
+                       return rc;
+
+               snprintf(stripe_name, sizeof(info->lti_key), DFID":%d",
+                        PFID(lu_object_fid(&dto->do_lu)), i);
+
+               rc = lod_sub_declare_delete(env, next,
+                                       (const struct dt_key *)stripe_name, th);
+               if (rc)
+                       return rc;
+
+               rc = lod_sub_declare_ref_del(env, next, th);
+               if (rc)
+                       return rc;
+       }
+
+       return 0;
+}
+
+/*
+ * delete stripes from dir master object, the lum_stripe_count in argument is
+ * the final stripe count, the stripes after that will be deleted, NB, they
+ * are not destroyed, but deleted from it's parent namespace, this function
+ * will be called in two places:
+ * 1. mdd_migrate_create() delete stripes from source, and append them to
+ *    target.
+ * 2. mdd_dir_layout_shrink() delete stripes from source, and destroy them.
+ */
+static int lod_dir_layout_delete(const struct lu_env *env,
+                                struct dt_object *dt,
+                                const struct lu_buf *buf,
+                                struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lod_object *lo = lod_dt_obj(dt);
+       struct dt_object *next = dt_object_child(dt);
+       struct lmv_user_md *lmu = buf->lb_buf;
+       __u32 final_stripe_count;
+       char *stripe_name = info->lti_key;
+       struct dt_object *dto;
+       int i;
+       int rc = 0;
+
+       ENTRY;
+
+       if (!lmu)
+               RETURN(-EINVAL);
+
+       final_stripe_count = le32_to_cpu(lmu->lum_stripe_count);
+       if (final_stripe_count >= lo->ldo_dir_stripe_count)
+               RETURN(-EINVAL);
+
+       for (i = final_stripe_count; i < lo->ldo_dir_stripe_count; i++) {
+               dto = lo->ldo_stripe[i];
+               LASSERT(dto);
+
+               rc = lod_sub_delete(env, dto,
+                                   (const struct dt_key *)dotdot, th);
+               if (rc)
+                       break;
+
+               snprintf(stripe_name, sizeof(info->lti_key), DFID":%d",
+                        PFID(lu_object_fid(&dto->do_lu)), i);
+
+               rc = lod_sub_delete(env, next,
+                                   (const struct dt_key *)stripe_name, th);
+               if (rc)
+                       break;
+
+               rc = lod_sub_ref_del(env, next, th);
+               if (rc)
+                       break;
+       }
+
+       lod_striping_free(env, lod_dt_obj(dt));
+
+       RETURN(rc);
+}
+
+/**
  * Implementation of dt_object_operations::do_declare_xattr_set.
  *
  * Used with regular (non-striped) objects. Basically it
@@ -2016,7 +2411,7 @@ static int lod_dir_declare_xattr_set(const struct lu_env *env,
                if (rc != 0)
                        RETURN(rc);
        } else if (strcmp(name, XATTR_NAME_LOV) == 0) {
-               rc = lod_verify_striping(d, buf, false, 0);
+               rc = lod_verify_striping(d, lo, buf, false);
                if (rc != 0)
                        RETURN(rc);
        }
@@ -2033,7 +2428,7 @@ static int lod_dir_declare_xattr_set(const struct lu_env *env,
                RETURN(0);
 
        /* set xattr to each stripes, if needed */
-       rc = lod_load_striping(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc != 0)
                RETURN(rc);
 
@@ -2056,10 +2451,11 @@ static int
 lod_obj_stripe_replace_parent_fid_cb(const struct lu_env *env,
                                     struct lod_object *lo,
                                     struct dt_object *dt, struct thandle *th,
-                                    int stripe_idx,
+                                    int comp_idx, int stripe_idx,
                                     struct lod_obj_stripe_cb_data *data)
 {
        struct lod_thread_info *info = lod_env_info(env);
+       struct lod_layout_component *comp = &lo->ldo_comp_entries[comp_idx];
        struct filter_fid *ff = &info->lti_ff;
        struct lu_buf *buf = &info->lti_buf;
        int rc;
@@ -2067,15 +2463,39 @@ lod_obj_stripe_replace_parent_fid_cb(const struct lu_env *env,
        buf->lb_buf = ff;
        buf->lb_len = sizeof(*ff);
        rc = dt_xattr_get(env, dt, buf, XATTR_NAME_FID);
-       if (rc == -ENODATA)
-               return 0;
-
-       if (rc < 0)
+       if (rc < 0) {
+               if (rc == -ENODATA)
+                       return 0;
                return rc;
+       }
+
+       /*
+        * locd_buf is set if it's called by dir migration, which doesn't check
+        * pfid and comp id.
+        */
+       if (data->locd_buf) {
+               memset(ff, 0, sizeof(*ff));
+               ff->ff_parent = *(struct lu_fid *)data->locd_buf->lb_buf;
+       } else {
+               filter_fid_le_to_cpu(ff, ff, sizeof(*ff));
+
+               if (lu_fid_eq(lod_object_fid(lo), &ff->ff_parent) &&
+                   ff->ff_layout.ol_comp_id == comp->llc_id)
+                       return 0;
 
-       ff->ff_parent = *lu_object_fid(&lo->ldo_obj.do_lu);
+               memset(ff, 0, sizeof(*ff));
+               ff->ff_parent = *lu_object_fid(&lo->ldo_obj.do_lu);
+       }
+
+       /* rewrite filter_fid */
        ff->ff_parent.f_ver = stripe_idx;
-       fid_cpu_to_le(&ff->ff_parent, &ff->ff_parent);
+       ff->ff_layout.ol_stripe_size = comp->llc_stripe_size;
+       ff->ff_layout.ol_stripe_count = comp->llc_stripe_count;
+       ff->ff_layout.ol_comp_id = comp->llc_id;
+       ff->ff_layout.ol_comp_start = comp->llc_extent.e_start;
+       ff->ff_layout.ol_comp_end = comp->llc_extent.e_end;
+       filter_fid_cpu_to_le(ff, ff, sizeof(*ff));
+
        if (data->locd_declare)
                rc = lod_sub_declare_xattr_set(env, dt, buf, XATTR_NAME_FID,
                                               LU_XATTR_REPLACE, th);
@@ -2103,20 +2523,20 @@ lod_obj_stripe_replace_parent_fid_cb(const struct lu_env *env,
  */
 static int lod_replace_parent_fid(const struct lu_env *env,
                                  struct dt_object *dt,
+                                 const struct lu_buf *buf,
                                  struct thandle *th, bool declare)
 {
        struct lod_object *lo = lod_dt_obj(dt);
        struct lod_thread_info  *info = lod_env_info(env);
-       struct lu_buf *buf = &info->lti_buf;
        struct filter_fid *ff;
-       struct lod_obj_stripe_cb_data data;
+       struct lod_obj_stripe_cb_data data = { { 0 } };
        int rc;
        ENTRY;
 
        LASSERT(S_ISREG(dt->do_lu.lo_header->loh_attr));
 
        /* set xattr to each stripes, if needed */
-       rc = lod_load_striping(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc != 0)
                RETURN(rc);
 
@@ -2129,13 +2549,10 @@ static int lod_replace_parent_fid(const struct lu_env *env,
                        RETURN(rc);
        }
 
-       buf->lb_buf = info->lti_ea_store;
-       buf->lb_len = info->lti_ea_store_size;
-
        data.locd_declare = declare;
-       rc = lod_obj_for_each_stripe(env, lo, th,
-                                    lod_obj_stripe_replace_parent_fid_cb,
-                                    &data);
+       data.locd_stripe_cb = lod_obj_stripe_replace_parent_fid_cb;
+       data.locd_buf = buf;
+       rc = lod_obj_for_each_stripe(env, lo, th, &data);
 
        RETURN(rc);
 }
@@ -2217,7 +2634,7 @@ static int lod_declare_layout_add(const struct lu_env *env,
                                  struct thandle *th)
 {
        struct lod_thread_info  *info = lod_env_info(env);
-       struct lod_layout_component *comp_array, *lod_comp;
+       struct lod_layout_component *comp_array, *lod_comp, *old_array;
        struct lod_device       *d = lu2lod_dev(dt->do_lu.lo_dev);
        struct dt_object *next = dt_object_child(dt);
        struct lov_desc         *desc = &d->lod_desc;
@@ -2225,14 +2642,15 @@ static int lod_declare_layout_add(const struct lu_env *env,
        struct lov_user_md_v3   *v3;
        struct lov_comp_md_v1   *comp_v1 = buf->lb_buf;
        __u32   magic;
-       __u64   prev_end;
-       int     i, rc, array_cnt;
+       int     i, rc, array_cnt, old_array_cnt;
        ENTRY;
 
        LASSERT(lo->ldo_is_composite);
 
-       prev_end = lo->ldo_comp_entries[lo->ldo_comp_cnt - 1].llc_extent.e_end;
-       rc = lod_verify_striping(d, buf, false, prev_end);
+       if (lo->ldo_flr_state != LCM_FL_NONE)
+               RETURN(-EBUSY);
+
+       rc = lod_verify_striping(d, lo, buf, false);
        if (rc != 0)
                RETURN(rc);
 
@@ -2265,16 +2683,11 @@ static int lod_declare_layout_add(const struct lu_env *env,
                lod_comp->llc_extent.e_start = ext->e_start;
                lod_comp->llc_extent.e_end = ext->e_end;
                lod_comp->llc_stripe_offset = v1->lmm_stripe_offset;
+               lod_comp->llc_flags = comp_v1->lcm_entries[i].lcme_flags;
 
                lod_comp->llc_stripe_count = v1->lmm_stripe_count;
-               if (!lod_comp->llc_stripe_count ||
-                   lod_comp->llc_stripe_count == (__u16)-1)
-                       lod_comp->llc_stripe_count =
-                               desc->ld_default_stripe_count;
                lod_comp->llc_stripe_size = v1->lmm_stripe_size;
-               if (!lod_comp->llc_stripe_size)
-                       lod_comp->llc_stripe_size =
-                               desc->ld_default_stripe_size;
+               lod_adjust_stripe_info(lod_comp, desc);
 
                if (v1->lmm_magic == LOV_USER_MAGIC_V3) {
                        v3 = (struct lov_user_md_v3 *) v1;
@@ -2287,17 +2700,28 @@ static int lod_declare_layout_add(const struct lu_env *env,
                }
        }
 
-       OBD_FREE(lo->ldo_comp_entries, sizeof(*lod_comp) * lo->ldo_comp_cnt);
+       old_array = lo->ldo_comp_entries;
+       old_array_cnt = lo->ldo_comp_cnt;
+
        lo->ldo_comp_entries = comp_array;
        lo->ldo_comp_cnt = array_cnt;
+
        /* No need to increase layout generation here, it will be increased
         * later when generating component ID for the new components */
 
        info->lti_buf.lb_len = lod_comp_md_size(lo, false);
        rc = lod_sub_declare_xattr_set(env, next, &info->lti_buf,
                                              XATTR_NAME_LOV, 0, th);
-       if (rc)
+       if (rc) {
+               lo->ldo_comp_entries = old_array;
+               lo->ldo_comp_cnt = old_array_cnt;
                GOTO(error, rc);
+       }
+
+       OBD_FREE(old_array, sizeof(*lod_comp) * old_array_cnt);
+
+       LASSERT(lo->ldo_mirror_count == 1);
+       lo->ldo_mirrors[0].lme_end = array_cnt - 1;
 
        RETURN(0);
 
@@ -2339,7 +2763,7 @@ static int lod_declare_layout_set(const struct lu_env *env,
        struct lod_device       *d = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_object       *lo = lod_dt_obj(dt);
        struct lov_comp_md_v1   *comp_v1 = buf->lb_buf;
-       __u32   magic, id;
+       __u32   magic;
        int     i, j, rc;
        bool    changed = false;
        ENTRY;
@@ -2366,15 +2790,43 @@ static int lod_declare_layout_set(const struct lu_env *env,
        }
 
        for (i = 0; i < comp_v1->lcm_entry_count; i++) {
-               id = comp_v1->lcm_entries[i].lcme_id;
+               __u32 id = comp_v1->lcm_entries[i].lcme_id;
+               __u32 flags = comp_v1->lcm_entries[i].lcme_flags;
+               __u32 mirror_flag = flags & LCME_MIRROR_FLAGS;
+               bool neg = flags & LCME_FL_NEG;
+
+               if (flags & LCME_FL_INIT) {
+                       if (changed)
+                               lod_striping_free(env, lo);
+                       RETURN(-EINVAL);
+               }
 
+               flags &= ~(LCME_MIRROR_FLAGS | LCME_FL_NEG);
                for (j = 0; j < lo->ldo_comp_cnt; j++) {
                        lod_comp = &lo->ldo_comp_entries[j];
-                       if (id == lod_comp->llc_id || id == LCME_ID_ALL) {
-                               lod_comp->llc_flags =
-                                       comp_v1->lcm_entries[i].lcme_flags;
-                               changed = true;
+
+                       /* lfs only put one flag in each entry */
+                       if ((flags && id != lod_comp->llc_id) ||
+                           (mirror_flag && mirror_id_of(id) !=
+                                           mirror_id_of(lod_comp->llc_id)))
+                               continue;
+
+                       if (neg) {
+                               if (flags)
+                                       lod_comp->llc_flags &= ~flags;
+                               if (mirror_flag)
+                                       lod_comp->llc_flags &= ~mirror_flag;
+                       } else {
+                               if (flags)
+                                       lod_comp->llc_flags |= flags;
+                               if (mirror_flag) {
+                                       lod_comp->llc_flags |= mirror_flag;
+                                       if (mirror_flag & LCME_FL_NOSYNC)
+                                               lod_comp->llc_timestamp =
+                                                      ktime_get_real_seconds();
+                               }
                        }
+                       changed = true;
                }
        }
 
@@ -2387,8 +2839,8 @@ static int lod_declare_layout_set(const struct lu_env *env,
        lod_obj_inc_layout_gen(lo);
 
        info->lti_buf.lb_len = lod_comp_md_size(lo, false);
-       rc = lod_sub_declare_xattr_set(env, dt, &info->lti_buf,
-                                      XATTR_NAME_LOV, 0, th);
+       rc = lod_sub_declare_xattr_set(env, dt_object_child(dt), &info->lti_buf,
+                                      XATTR_NAME_LOV, LU_XATTR_REPLACE, th);
        RETURN(rc);
 }
 
@@ -2421,9 +2873,8 @@ static int lod_declare_layout_del(const struct lu_env *env,
 
        LASSERT(lo->ldo_is_composite);
 
-       rc = lod_verify_striping(d, buf, false, 0);
-       if (rc != 0)
-               RETURN(rc);
+       if (lo->ldo_flr_state != LCM_FL_NONE)
+               RETURN(-EBUSY);
 
        magic = comp_v1->lcm_magic;
        if (magic == __swab32(LOV_USER_MAGIC_COMP_V1)) {
@@ -2449,6 +2900,12 @@ static int lod_declare_layout_del(const struct lu_env *env,
                RETURN(-EINVAL);
        }
 
+       if (id == LCME_ID_INVAL && !flags) {
+               CDEBUG(D_LAYOUT, "%s: no id or flags specified.\n",
+                      lod2obd(d)->obd_name);
+               RETURN(-EINVAL);
+       }
+
        if (flags & LCME_FL_NEG) {
                neg_flags = flags & ~LCME_FL_NEG;
                flags = 0;
@@ -2544,7 +3001,6 @@ static int lod_declare_modify_layout(const struct lu_env *env,
 {
        struct lod_device *d = lu2lod_dev(dt->do_lu.lo_dev);
        struct lod_object *lo = lod_dt_obj(dt);
-       struct dt_object *next = dt_object_child(&lo->ldo_obj);
        char *op;
        int rc, len = strlen(XATTR_LUSTRE_LOV);
        ENTRY;
@@ -2558,8 +3014,7 @@ static int lod_declare_modify_layout(const struct lu_env *env,
        }
        len++;
 
-       dt_write_lock(env, next, 0);
-       rc = lod_load_striping_locked(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc)
                GOTO(unlock, rc);
 
@@ -2584,9 +3039,241 @@ static int lod_declare_modify_layout(const struct lu_env *env,
        }
 unlock:
        if (rc)
-               lod_object_free_striping(env, lo);
-       dt_write_unlock(env, next);
+               lod_striping_free(env, lo);
+
+       RETURN(rc);
+}
+
+/**
+ * Convert a plain file lov_mds_md to a composite layout.
+ *
+ * \param[in,out] info the thread info::lti_ea_store buffer contains little
+ *                     endian plain file layout
+ *
+ * \retval             0 on success, <0 on failure
+ */
+static int lod_layout_convert(struct lod_thread_info *info)
+{
+       struct lov_mds_md *lmm = info->lti_ea_store;
+       struct lov_mds_md *lmm_save;
+       struct lov_comp_md_v1 *lcm;
+       struct lov_comp_md_entry_v1 *lcme;
+       size_t size;
+       __u32 blob_size;
+       int rc = 0;
+       ENTRY;
+
+       /* realloc buffer to a composite layout which contains one component */
+       blob_size = lov_mds_md_size(le16_to_cpu(lmm->lmm_stripe_count),
+                                   le32_to_cpu(lmm->lmm_magic));
+       size = sizeof(*lcm) + sizeof(*lcme) + blob_size;
+
+       OBD_ALLOC_LARGE(lmm_save, blob_size);
+       if (!lmm_save)
+               GOTO(out, rc = -ENOMEM);
+
+       memcpy(lmm_save, lmm, blob_size);
+
+       if (info->lti_ea_store_size < size) {
+               rc = lod_ea_store_resize(info, size);
+               if (rc)
+                       GOTO(out, rc);
+       }
+
+       lcm = info->lti_ea_store;
+       lcm->lcm_magic = cpu_to_le32(LOV_MAGIC_COMP_V1);
+       lcm->lcm_size = cpu_to_le32(size);
+       lcm->lcm_layout_gen = cpu_to_le32(le16_to_cpu(
+                                               lmm_save->lmm_layout_gen));
+       lcm->lcm_flags = cpu_to_le16(LCM_FL_NONE);
+       lcm->lcm_entry_count = cpu_to_le16(1);
+       lcm->lcm_mirror_count = 0;
+
+       lcme = &lcm->lcm_entries[0];
+       lcme->lcme_flags = cpu_to_le32(LCME_FL_INIT);
+       lcme->lcme_extent.e_start = 0;
+       lcme->lcme_extent.e_end = cpu_to_le64(OBD_OBJECT_EOF);
+       lcme->lcme_offset = cpu_to_le32(sizeof(*lcm) + sizeof(*lcme));
+       lcme->lcme_size = cpu_to_le32(blob_size);
+
+       memcpy((char *)lcm + lcme->lcme_offset, (char *)lmm_save, blob_size);
+
+       EXIT;
+out:
+       if (lmm_save)
+               OBD_FREE_LARGE(lmm_save, blob_size);
+       return rc;
+}
+
+/**
+ * Merge layouts to form a mirrored file.
+ */
+static int lod_declare_layout_merge(const struct lu_env *env,
+               struct dt_object *dt, const struct lu_buf *mbuf,
+               struct thandle *th)
+{
+       struct lod_thread_info  *info = lod_env_info(env);
+       struct lu_buf           *buf = &info->lti_buf;
+       struct lod_object       *lo = lod_dt_obj(dt);
+       struct lov_comp_md_v1   *lcm;
+       struct lov_comp_md_v1   *cur_lcm;
+       struct lov_comp_md_v1   *merge_lcm;
+       struct lov_comp_md_entry_v1     *lcme;
+       size_t size = 0;
+       size_t offset;
+       __u16 cur_entry_count;
+       __u16 merge_entry_count;
+       __u32 id = 0;
+       __u16 mirror_id = 0;
+       __u32 mirror_count;
+       int     rc, i;
+       ENTRY;
+
+       merge_lcm = mbuf->lb_buf;
+       if (mbuf->lb_len < sizeof(*merge_lcm))
+               RETURN(-EINVAL);
+
+       /* must be an existing layout from disk */
+       if (le32_to_cpu(merge_lcm->lcm_magic) != LOV_MAGIC_COMP_V1)
+               RETURN(-EINVAL);
+
+       merge_entry_count = le16_to_cpu(merge_lcm->lcm_entry_count);
+
+       /* do not allow to merge two mirrored files */
+       if (le16_to_cpu(merge_lcm->lcm_mirror_count))
+               RETURN(-EBUSY);
+
+       /* verify the target buffer */
+       rc = lod_get_lov_ea(env, lo);
+       if (rc <= 0)
+               RETURN(rc ? : -ENODATA);
+
+       cur_lcm = info->lti_ea_store;
+       switch (le32_to_cpu(cur_lcm->lcm_magic)) {
+       case LOV_MAGIC_V1:
+       case LOV_MAGIC_V3:
+               rc = lod_layout_convert(info);
+               break;
+       case LOV_MAGIC_COMP_V1:
+               rc = 0;
+               break;
+       default:
+               rc = -EINVAL;
+       }
+       if (rc)
+               RETURN(rc);
+
+       /* info->lti_ea_store could be reallocated in lod_layout_convert() */
+       cur_lcm = info->lti_ea_store;
+       cur_entry_count = le16_to_cpu(cur_lcm->lcm_entry_count);
+
+       /* 'lcm_mirror_count + 1' is the current # of mirrors the file has */
+       mirror_count = le16_to_cpu(cur_lcm->lcm_mirror_count) + 1;
+       if (mirror_count + 1 > LUSTRE_MIRROR_COUNT_MAX)
+               RETURN(-ERANGE);
+
+       /* size of new layout */
+       size = le32_to_cpu(cur_lcm->lcm_size) +
+              le32_to_cpu(merge_lcm->lcm_size) - sizeof(*cur_lcm);
+
+       memset(buf, 0, sizeof(*buf));
+       lu_buf_alloc(buf, size);
+       if (buf->lb_buf == NULL)
+               RETURN(-ENOMEM);
+
+       lcm = buf->lb_buf;
+       memcpy(lcm, cur_lcm, sizeof(*lcm) + cur_entry_count * sizeof(*lcme));
+
+       offset = sizeof(*lcm) +
+                sizeof(*lcme) * (cur_entry_count + merge_entry_count);
+       for (i = 0; i < cur_entry_count; i++) {
+               struct lov_comp_md_entry_v1 *cur_lcme;
+
+               lcme = &lcm->lcm_entries[i];
+               cur_lcme = &cur_lcm->lcm_entries[i];
+
+               lcme->lcme_offset = cpu_to_le32(offset);
+               memcpy((char *)lcm + offset,
+                      (char *)cur_lcm + le32_to_cpu(cur_lcme->lcme_offset),
+                      le32_to_cpu(lcme->lcme_size));
+
+               offset += le32_to_cpu(lcme->lcme_size);
+
+               if (mirror_count == 1 &&
+                   mirror_id_of(le32_to_cpu(lcme->lcme_id)) == 0) {
+                       /* Add mirror from a non-flr file, create new mirror ID.
+                        * Otherwise, keep existing mirror's component ID, used
+                        * for mirror extension.
+                        */
+                       id = pflr_id(1, i + 1);
+                       lcme->lcme_id = cpu_to_le32(id);
+               }
+
+               id = MAX(le32_to_cpu(lcme->lcme_id), id);
+       }
+
+       mirror_id = mirror_id_of(id) + 1;
+       for (i = 0; i < merge_entry_count; i++) {
+               struct lov_comp_md_entry_v1 *merge_lcme;
+
+               merge_lcme = &merge_lcm->lcm_entries[i];
+               lcme = &lcm->lcm_entries[cur_entry_count + i];
+
+               *lcme = *merge_lcme;
+               lcme->lcme_offset = cpu_to_le32(offset);
+
+               id = pflr_id(mirror_id, i + 1);
+               lcme->lcme_id = cpu_to_le32(id);
+
+               memcpy((char *)lcm + offset,
+                      (char *)merge_lcm + le32_to_cpu(merge_lcme->lcme_offset),
+                      le32_to_cpu(lcme->lcme_size));
+
+               offset += le32_to_cpu(lcme->lcme_size);
+       }
+
+       /* fixup layout information */
+       lod_obj_inc_layout_gen(lo);
+       lcm->lcm_layout_gen = cpu_to_le32(lo->ldo_layout_gen);
+       lcm->lcm_size = cpu_to_le32(size);
+       lcm->lcm_entry_count = cpu_to_le16(cur_entry_count + merge_entry_count);
+       lcm->lcm_mirror_count = cpu_to_le16(mirror_count);
+       if ((le16_to_cpu(lcm->lcm_flags) & LCM_FL_FLR_MASK) == LCM_FL_NONE)
+               lcm->lcm_flags = cpu_to_le32(LCM_FL_RDONLY);
+
+       rc = lod_striping_reload(env, lo, buf);
+       if (rc)
+               GOTO(out, rc);
+
+       rc = lod_sub_declare_xattr_set(env, dt_object_child(dt), buf,
+                                       XATTR_NAME_LOV, LU_XATTR_REPLACE, th);
+
+out:
+       lu_buf_free(buf);
+       RETURN(rc);
+}
+
+/**
+ * Split layouts, just set the LOVEA with the layout from mbuf.
+ */
+static int lod_declare_layout_split(const struct lu_env *env,
+               struct dt_object *dt, const struct lu_buf *mbuf,
+               struct thandle *th)
+{
+       struct lod_object *lo = lod_dt_obj(dt);
+       struct lov_comp_md_v1 *lcm = mbuf->lb_buf;
+       int rc;
+       ENTRY;
+
+       lod_obj_inc_layout_gen(lo);
+       lcm->lcm_layout_gen = cpu_to_le32(lo->ldo_layout_gen);
+
+       rc = lod_striping_reload(env, lo, mbuf);
+       if (rc)
+               RETURN(rc);
 
+       rc = lod_sub_declare_xattr_set(env, dt_object_child(dt), mbuf,
+                                      XATTR_NAME_LOV, LU_XATTR_REPLACE, th);
        RETURN(rc);
 }
 
@@ -2613,7 +3300,8 @@ static int lod_declare_xattr_set(const struct lu_env *env,
        ENTRY;
 
        mode = dt->do_lu.lo_header->loh_attr & S_IFMT;
-       if ((S_ISREG(mode) || mode == 0) && !(fl & LU_XATTR_REPLACE) &&
+       if ((S_ISREG(mode) || mode == 0) &&
+           !(fl & (LU_XATTR_REPLACE | LU_XATTR_MERGE | LU_XATTR_SPLIT)) &&
            (strcmp(name, XATTR_NAME_LOV) == 0 ||
             strcmp(name, XATTR_LUSTRE_LOV) == 0)) {
                /*
@@ -2635,6 +3323,14 @@ static int lod_declare_xattr_set(const struct lu_env *env,
                        attr->la_mode = S_IFREG;
                }
                rc = lod_declare_striped_create(env, dt, attr, buf, th);
+       } else if (fl & LU_XATTR_MERGE) {
+               LASSERT(strcmp(name, XATTR_NAME_LOV) == 0 ||
+                       strcmp(name, XATTR_LUSTRE_LOV) == 0);
+               rc = lod_declare_layout_merge(env, dt, buf, th);
+       } else if (fl & LU_XATTR_SPLIT) {
+               LASSERT(strcmp(name, XATTR_NAME_LOV) == 0 ||
+                       strcmp(name, XATTR_LUSTRE_LOV) == 0);
+               rc = lod_declare_layout_split(env, dt, buf, th);
        } else if (S_ISREG(mode) &&
                   strlen(name) > strlen(XATTR_LUSTRE_LOV) + 1 &&
                   strncmp(name, XATTR_LUSTRE_LOV,
@@ -2647,10 +3343,24 @@ static int lod_declare_xattr_set(const struct lu_env *env,
                        RETURN(-ENOENT);
 
                rc = lod_declare_modify_layout(env, dt, name, buf, th);
+       } else if (strncmp(name, XATTR_NAME_LMV, strlen(XATTR_NAME_LMV)) == 0 &&
+                  strlen(name) > strlen(XATTR_NAME_LMV) + 1) {
+               const char *op = name + strlen(XATTR_NAME_LMV) + 1;
+
+               rc = -ENOTSUPP;
+               if (strcmp(op, "add") == 0)
+                       rc = lod_dir_declare_layout_add(env, dt, buf, th);
+               else if (strcmp(op, "del") == 0)
+                       rc = lod_dir_declare_layout_delete(env, dt, buf, th);
+               else if (strcmp(op, "set") == 0)
+                       rc = lod_sub_declare_xattr_set(env, next, buf,
+                                                      XATTR_NAME_LMV, fl, th);
+
+               RETURN(rc);
        } else if (S_ISDIR(mode)) {
                rc = lod_dir_declare_xattr_set(env, dt, buf, name, fl, th);
        } else if (strcmp(name, XATTR_NAME_FID) == 0) {
-               rc = lod_replace_parent_fid(env, dt, th, true);
+               rc = lod_replace_parent_fid(env, dt, buf, th, true);
        } else {
                rc = lod_sub_declare_xattr_set(env, next, buf, name, fl, th);
        }
@@ -2784,6 +3494,7 @@ static int lod_xattr_set_lov_on_dir(const struct lu_env *env,
        lum = buf->lb_buf;
 
        switch (lum->lmm_magic) {
+       case LOV_USER_MAGIC_SPECIFIC:
        case LOV_USER_MAGIC_V3:
                v3 = buf->lb_buf;
                if (v3->lmm_pool_name[0] != '\0')
@@ -2941,35 +3652,38 @@ static int lod_xattr_set_lmv(const struct lu_env *env, struct dt_object *dt,
 
        rec->rec_type = S_IFDIR;
        for (i = 0; i < lo->ldo_dir_stripe_count; i++) {
-               struct dt_object *dto;
-               char             *stripe_name = info->lti_key;
-               struct lu_name          *sname;
-               struct linkea_data       ldata          = { NULL };
-               struct lu_buf            linkea_buf;
-
-               dto = lo->ldo_stripe[i];
+               struct dt_object *dto = lo->ldo_stripe[i];
+               char *stripe_name = info->lti_key;
+               struct lu_name *sname;
+               struct linkea_data ldata = { NULL };
+               struct lu_buf linkea_buf;
+
+               /* if it's source stripe of migrating directory, don't create */
+               if (!((lo->ldo_dir_hash_type & LMV_HASH_FLAG_MIGRATION) &&
+                     i >= lo->ldo_dir_migrate_offset)) {
+                       dt_write_lock(env, dto, MOR_TGT_CHILD);
+                       rc = lod_sub_create(env, dto, attr, NULL, dof, th);
+                       if (rc != 0) {
+                               dt_write_unlock(env, dto);
+                               GOTO(out, rc);
+                       }
 
-               dt_write_lock(env, dto, MOR_TGT_CHILD);
-               rc = lod_sub_create(env, dto, attr, NULL, dof, th);
-               if (rc != 0) {
+                       rc = lod_sub_ref_add(env, dto, th);
                        dt_write_unlock(env, dto);
-                       GOTO(out, rc);
-               }
-
-               rc = lod_sub_ref_add(env, dto, th);
-               dt_write_unlock(env, dto);
-               if (rc != 0)
-                       GOTO(out, rc);
+                       if (rc != 0)
+                               GOTO(out, rc);
 
-               rec->rec_fid = lu_object_fid(&dto->do_lu);
-               rc = lod_sub_insert(env, dto, (const struct dt_rec *)rec,
-                                   (const struct dt_key *)dot, th, 0);
-               if (rc != 0)
-                       GOTO(out, rc);
+                       rec->rec_fid = lu_object_fid(&dto->do_lu);
+                       rc = lod_sub_insert(env, dto,
+                                           (const struct dt_rec *)rec,
+                                           (const struct dt_key *)dot, th);
+                       if (rc != 0)
+                               GOTO(out, rc);
+               }
 
                rec->rec_fid = lu_object_fid(&dt->do_lu);
                rc = lod_sub_insert(env, dto, (struct dt_rec *)rec,
-                                   (const struct dt_key *)dotdot, th, 0);
+                                   (const struct dt_key *)dotdot, th);
                if (rc != 0)
                        GOTO(out, rc);
 
@@ -3013,7 +3727,7 @@ static int lod_xattr_set_lmv(const struct lu_env *env, struct dt_object *dt,
                rec->rec_fid = lu_object_fid(&dto->do_lu);
                rc = lod_sub_insert(env, dt_object_child(dt),
                                    (const struct dt_rec *)rec,
-                                   (const struct dt_key *)stripe_name, th, 0);
+                                   (const struct dt_key *)stripe_name, th);
                if (rc != 0)
                        GOTO(out, rc);
 
@@ -3047,6 +3761,7 @@ out:
  * \param[in] env      execution environment
  * \param[in] dt       object
  * \param[in] attr     attributes the stripes will be created with
+ * \param[in] lmu      lmv_user_md if MDT indices are specified
  * \param[in] dof      format of stripes (see OSD API description)
  * \param[in] th       transaction handle
  * \param[in] declare  where to call "declare" or "execute" methods
@@ -3057,6 +3772,7 @@ out:
 static int lod_dir_striping_create_internal(const struct lu_env *env,
                                            struct dt_object *dt,
                                            struct lu_attr *attr,
+                                           const struct lu_buf *lmu,
                                            struct dt_object_format *dof,
                                            struct thandle *th,
                                            bool declare)
@@ -3073,31 +3789,34 @@ static int lod_dir_striping_create_internal(const struct lu_env *env,
 
        if (!LMVEA_DELETE_VALUES(lo->ldo_dir_stripe_count,
                                 lo->ldo_dir_stripe_offset)) {
-               struct lmv_user_md_v1 *v1 = info->lti_ea_store;
-               int stripe_count = lo->ldo_dir_stripe_count;
+               if (!lmu) {
+                       struct lmv_user_md_v1 *v1 = info->lti_ea_store;
+                       int stripe_count = lo->ldo_dir_stripe_count;
 
-               if (info->lti_ea_store_size < sizeof(*v1)) {
-                       rc = lod_ea_store_resize(info, sizeof(*v1));
-                       if (rc != 0)
-                               RETURN(rc);
-                       v1 = info->lti_ea_store;
-               }
+                       if (info->lti_ea_store_size < sizeof(*v1)) {
+                               rc = lod_ea_store_resize(info, sizeof(*v1));
+                               if (rc != 0)
+                                       RETURN(rc);
+                               v1 = info->lti_ea_store;
+                       }
 
-               memset(v1, 0, sizeof(*v1));
-               v1->lum_magic = cpu_to_le32(LMV_USER_MAGIC);
-               v1->lum_stripe_count = cpu_to_le32(stripe_count);
-               v1->lum_stripe_offset =
-                               cpu_to_le32(lo->ldo_dir_stripe_offset);
+                       memset(v1, 0, sizeof(*v1));
+                       v1->lum_magic = cpu_to_le32(LMV_USER_MAGIC);
+                       v1->lum_stripe_count = cpu_to_le32(stripe_count);
+                       v1->lum_stripe_offset =
+                                       cpu_to_le32(lo->ldo_dir_stripe_offset);
 
-               info->lti_buf.lb_buf = v1;
-               info->lti_buf.lb_len = sizeof(*v1);
+                       info->lti_buf.lb_buf = v1;
+                       info->lti_buf.lb_len = sizeof(*v1);
+                       lmu = &info->lti_buf;
+               }
 
                if (declare)
-                       rc = lod_declare_xattr_set_lmv(env, dt, attr,
-                                                      &info->lti_buf, dof, th);
+                       rc = lod_declare_xattr_set_lmv(env, dt, attr, lmu, dof,
+                                                      th);
                else
-                       rc = lod_xattr_set_lmv(env, dt, &info->lti_buf,
-                                              XATTR_NAME_LMV, 0, th);
+                       rc = lod_xattr_set_lmv(env, dt, lmu, XATTR_NAME_LMV, 0,
+                                              th);
                if (rc != 0)
                        RETURN(rc);
        }
@@ -3175,10 +3894,12 @@ static int lod_dir_striping_create_internal(const struct lu_env *env,
 static int lod_declare_dir_striping_create(const struct lu_env *env,
                                           struct dt_object *dt,
                                           struct lu_attr *attr,
+                                          struct lu_buf *lmu,
                                           struct dt_object_format *dof,
                                           struct thandle *th)
 {
-       return lod_dir_striping_create_internal(env, dt, attr, dof, th, true);
+       return lod_dir_striping_create_internal(env, dt, attr, lmu, dof, th,
+                                               true);
 }
 
 static int lod_dir_striping_create(const struct lu_env *env,
@@ -3187,7 +3908,8 @@ static int lod_dir_striping_create(const struct lu_env *env,
                                   struct dt_object_format *dof,
                                   struct thandle *th)
 {
-       return lod_dir_striping_create_internal(env, dt, attr, dof, th, false);
+       return lod_dir_striping_create_internal(env, dt, attr, NULL, dof, th,
+                                               false);
 }
 
 /**
@@ -3219,7 +3941,7 @@ static int lod_generate_and_set_lovea(const struct lu_env *env,
        LASSERT(lo);
 
        if (lo->ldo_comp_cnt == 0) {
-               lod_object_free_striping(env, lo);
+               lod_striping_free(env, lo);
                rc = lod_sub_xattr_del(env, next, XATTR_NAME_LOV, th);
                RETURN(rc);
        }
@@ -3293,6 +4015,9 @@ static int lod_layout_del(const struct lu_env *env, struct dt_object *dt,
                OBD_FREE(lod_comp->llc_stripe, sizeof(struct dt_object *) *
                                        lod_comp->llc_stripes_allocated);
                lod_comp->llc_stripe = NULL;
+               OBD_FREE(lod_comp->llc_ost_indices,
+                        sizeof(__u32) * lod_comp->llc_stripes_allocated);
+               lod_comp->llc_ost_indices = NULL;
                lod_comp->llc_stripes_allocated = 0;
                lod_obj_set_pool(lo, i, NULL);
                if (lod_comp->llc_ostlist.op_array) {
@@ -3318,6 +4043,9 @@ static int lod_layout_del(const struct lu_env *env, struct dt_object *dt,
                         sizeof(*comp_array) * lo->ldo_comp_cnt);
                lo->ldo_comp_entries = comp_array;
                lo->ldo_comp_cnt = left;
+
+               LASSERT(lo->ldo_mirror_count == 1);
+               lo->ldo_mirrors[0].lme_end = left - 1;
                lod_obj_inc_layout_gen(lo);
        } else {
                lod_free_comp_entries(lo);
@@ -3340,10 +4068,14 @@ static int lod_layout_del(const struct lu_env *env, struct dt_object *dt,
        EXIT;
 out:
        if (rc)
-               lod_object_free_striping(env, lo);
+               lod_striping_free(env, lo);
        return rc;
 }
 
+
+static int lod_get_default_lov_striping(const struct lu_env *env,
+                                       struct lod_object *lo,
+                                       struct lod_default_striping *lds);
 /**
  * Implementation of dt_object_operations::do_xattr_set.
  *
@@ -3372,21 +4104,80 @@ static int lod_xattr_set(const struct lu_env *env,
 
        if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
            strcmp(name, XATTR_NAME_LMV) == 0) {
-               struct lmv_mds_md_v1 *lmm = buf->lb_buf;
+               rc = lod_dir_striping_create(env, dt, NULL, NULL, th);
+               RETURN(rc);
+       } else if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
+                  strncmp(name, XATTR_NAME_LMV, strlen(XATTR_NAME_LMV)) == 0 &&
+                  strlen(name) > strlen(XATTR_NAME_LMV) + 1) {
+               const char *op = name + strlen(XATTR_NAME_LMV) + 1;
 
-               if (lmm != NULL && le32_to_cpu(lmm->lmv_hash_type) &
-                                               LMV_HASH_FLAG_MIGRATION)
-                       rc = lod_sub_xattr_set(env, next, buf, name, fl, th);
-               else
-                       rc = lod_dir_striping_create(env, dt, NULL, NULL, th);
+               rc = -ENOTSUPP;
+               /*
+                * XATTR_NAME_LMV".add" is never called, but only declared,
+                * because lod_xattr_set_lmv() will do the addition.
+                */
+               if (strcmp(op, "del") == 0)
+                       rc = lod_dir_layout_delete(env, dt, buf, th);
+               else if (strcmp(op, "set") == 0)
+                       rc = lod_sub_xattr_set(env, next, buf, XATTR_NAME_LMV,
+                                              fl, th);
 
                RETURN(rc);
-       }
-
-       if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
+       } else if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
            strcmp(name, XATTR_NAME_LOV) == 0) {
-               /* default LOVEA */
-               rc = lod_xattr_set_lov_on_dir(env, dt, buf, name, fl, th);
+               struct lod_thread_info *info = lod_env_info(env);
+               struct lod_default_striping *lds = &info->lti_def_striping;
+               struct lov_user_md_v1 *v1 = buf->lb_buf;
+               char pool[LOV_MAXPOOLNAME + 1];
+               bool is_del;
+
+               /* get existing striping config */
+               rc = lod_get_default_lov_striping(env, lod_dt_obj(dt), lds);
+               if (rc)
+                       RETURN(rc);
+
+               memset(pool, 0, sizeof(pool));
+               if (lds->lds_def_striping_set == 1)
+                       lod_layout_get_pool(lds->lds_def_comp_entries,
+                                           lds->lds_def_comp_cnt, pool,
+                                           sizeof(pool));
+
+               is_del = LOVEA_DELETE_VALUES(v1->lmm_stripe_size,
+                                            v1->lmm_stripe_count,
+                                            v1->lmm_stripe_offset,
+                                            NULL);
+
+               /* Retain the pool name if it is not given */
+               if (v1->lmm_magic == LOV_USER_MAGIC_V1 && pool[0] != '\0' &&
+                       !is_del) {
+                       struct lod_thread_info *info = lod_env_info(env);
+                       struct lov_user_md_v3 *v3  = info->lti_ea_store;
+
+                       memset(v3, 0, sizeof(*v3));
+                       v3->lmm_magic = cpu_to_le32(LOV_USER_MAGIC_V3);
+                       v3->lmm_pattern = cpu_to_le32(v1->lmm_pattern);
+                       v3->lmm_stripe_count =
+                                       cpu_to_le32(v1->lmm_stripe_count);
+                       v3->lmm_stripe_offset =
+                                       cpu_to_le32(v1->lmm_stripe_offset);
+                       v3->lmm_stripe_size = cpu_to_le32(v1->lmm_stripe_size);
+
+                       strlcpy(v3->lmm_pool_name, pool,
+                               sizeof(v3->lmm_pool_name));
+
+                       info->lti_buf.lb_buf = v3;
+                       info->lti_buf.lb_len = sizeof(*v3);
+                       rc = lod_xattr_set_lov_on_dir(env, dt, &info->lti_buf,
+                                                     name, fl, th);
+               } else {
+                       rc = lod_xattr_set_lov_on_dir(env, dt, buf, name,
+                                                     fl, th);
+               }
+
+               if (lds->lds_def_striping_set == 1 &&
+                   lds->lds_def_comp_entries != NULL)
+                       lod_free_def_comp_entries(lds);
+
                RETURN(rc);
        } else if (S_ISDIR(dt->do_lu.lo_header->loh_attr) &&
                   strcmp(name, XATTR_NAME_DEFAULT_LMV) == 0) {
@@ -3404,7 +4195,7 @@ static int lod_xattr_set(const struct lu_env *env,
                 * defines striping, then create() does the work */
                if (fl & LU_XATTR_REPLACE) {
                        /* free stripes, then update disk */
-                       lod_object_free_striping(env, lod_dt_obj(dt));
+                       lod_striping_free(env, lod_dt_obj(dt));
 
                        rc = lod_sub_xattr_set(env, next, buf, name, fl, th);
                } else if (dt_object_remote(dt)) {
@@ -3438,7 +4229,7 @@ static int lod_xattr_set(const struct lu_env *env,
                }
                RETURN(rc);
        } else if (strcmp(name, XATTR_NAME_FID) == 0) {
-               rc = lod_replace_parent_fid(env, dt, th, false);
+               rc = lod_replace_parent_fid(env, dt, buf, th, false);
 
                RETURN(rc);
        }
@@ -3459,12 +4250,13 @@ static int lod_declare_xattr_del(const struct lu_env *env,
                                 struct dt_object *dt, const char *name,
                                 struct thandle *th)
 {
-       struct lod_object       *lo = lod_dt_obj(dt);
-       int                     rc;
-       int                     i;
+       struct lod_object *lo = lod_dt_obj(dt);
+       struct dt_object *next = dt_object_child(dt);
+       int i;
+       int rc;
        ENTRY;
 
-       rc = lod_sub_declare_xattr_del(env, dt_object_child(dt), name, th);
+       rc = lod_sub_declare_xattr_del(env, next, name, th);
        if (rc != 0)
                RETURN(rc);
 
@@ -3472,7 +4264,7 @@ static int lod_declare_xattr_del(const struct lu_env *env,
                RETURN(0);
 
        /* set xattr to each stripes, if needed */
-       rc = lod_load_striping(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc != 0)
                RETURN(rc);
 
@@ -3480,9 +4272,10 @@ static int lod_declare_xattr_del(const struct lu_env *env,
                RETURN(0);
 
        for (i = 0; i < lo->ldo_dir_stripe_count; i++) {
-               LASSERT(lo->ldo_stripe[i]);
-               rc = lod_sub_declare_xattr_del(env, lo->ldo_stripe[i],
-                                              name, th);
+               struct dt_object *dto = lo->ldo_stripe[i];
+
+               LASSERT(dto);
+               rc = lod_sub_declare_xattr_del(env, dto, name, th);
                if (rc != 0)
                        break;
        }
@@ -3507,8 +4300,8 @@ static int lod_xattr_del(const struct lu_env *env, struct dt_object *dt,
        int                     i;
        ENTRY;
 
-       if (!strcmp(name, XATTR_NAME_LOV))
-               lod_object_free_striping(env, lod_dt_obj(dt));
+       if (!strcmp(name, XATTR_NAME_LOV) || !strcmp(name, XATTR_NAME_LMV))
+               lod_striping_free(env, lod_dt_obj(dt));
 
        rc = lod_sub_xattr_del(env, next, name, th);
        if (rc != 0 || !S_ISDIR(dt->do_lu.lo_header->loh_attr))
@@ -3518,9 +4311,11 @@ static int lod_xattr_del(const struct lu_env *env, struct dt_object *dt,
                RETURN(0);
 
        for (i = 0; i < lo->ldo_dir_stripe_count; i++) {
-               LASSERT(lo->ldo_stripe[i]);
+               struct dt_object *dto = lo->ldo_stripe[i];
 
-               rc = lod_sub_xattr_del(env, lo->ldo_stripe[i], name, th);
+               LASSERT(dto);
+
+               rc = lod_sub_xattr_del(env, dto, name, th);
                if (rc != 0)
                        break;
        }
@@ -3545,6 +4340,52 @@ static inline int lod_object_will_be_striped(int is_reg, const struct lu_fid *fi
        return (is_reg && fid_seq(fid) != FID_SEQ_LOCAL_FILE);
 }
 
+/**
+ * Copy OST list from layout provided by user.
+ *
+ * \param[in] lod_comp         layout_component to be filled
+ * \param[in] v3               LOV EA V3 user data
+ *
+ * \retval             0 on success
+ * \retval             negative if failed
+ */
+int lod_comp_copy_ost_lists(struct lod_layout_component *lod_comp,
+                           struct lov_user_md_v3 *v3)
+{
+       int j;
+
+       ENTRY;
+
+       if (v3->lmm_stripe_offset == LOV_OFFSET_DEFAULT)
+               v3->lmm_stripe_offset = v3->lmm_objects[0].l_ost_idx;
+
+       if (lod_comp->llc_ostlist.op_array) {
+               if (lod_comp->llc_ostlist.op_size >=
+                   v3->lmm_stripe_count * sizeof(__u32))  {
+                       lod_comp->llc_ostlist.op_count =
+                                       v3->lmm_stripe_count;
+                       goto skip;
+               }
+               OBD_FREE(lod_comp->llc_ostlist.op_array,
+                        lod_comp->llc_ostlist.op_size);
+       }
+
+       /* copy ost list from lmm */
+       lod_comp->llc_ostlist.op_count = v3->lmm_stripe_count;
+       lod_comp->llc_ostlist.op_size = v3->lmm_stripe_count * sizeof(__u32);
+       OBD_ALLOC(lod_comp->llc_ostlist.op_array,
+                 lod_comp->llc_ostlist.op_size);
+       if (!lod_comp->llc_ostlist.op_array)
+               RETURN(-ENOMEM);
+skip:
+       for (j = 0; j < v3->lmm_stripe_count; j++) {
+               lod_comp->llc_ostlist.op_array[j] =
+                       v3->lmm_objects[j].l_ost_idx;
+       }
+
+       RETURN(0);
+}
+
 
 /**
  * Get default striping.
@@ -3565,8 +4406,9 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
        struct lov_user_md_v3 *v3 = NULL;
        struct lov_comp_md_v1 *comp_v1 = NULL;
        __u16   comp_cnt;
+       __u16   mirror_cnt;
        bool    composite;
-       int     rc, i;
+       int     rc, i, j;
        ENTRY;
 
        lds->lds_def_striping_set = 0;
@@ -3584,13 +4426,19 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
        } else if (v1->lmm_magic == __swab32(LOV_USER_MAGIC_V3)) {
                v3 = (struct lov_user_md_v3 *)v1;
                lustre_swab_lov_user_md_v3(v3);
+       } else if (v1->lmm_magic == __swab32(LOV_USER_MAGIC_SPECIFIC)) {
+               v3 = (struct lov_user_md_v3 *)v1;
+               lustre_swab_lov_user_md_v3(v3);
+               lustre_swab_lov_user_md_objects(v3->lmm_objects,
+                                               v3->lmm_stripe_count);
        } else if (v1->lmm_magic == __swab32(LOV_USER_MAGIC_COMP_V1)) {
                comp_v1 = (struct lov_comp_md_v1 *)v1;
                lustre_swab_lov_comp_md_v1(comp_v1);
        }
 
        if (v1->lmm_magic != LOV_MAGIC_V3 && v1->lmm_magic != LOV_MAGIC_V1 &&
-           v1->lmm_magic != LOV_MAGIC_COMP_V1)
+           v1->lmm_magic != LOV_MAGIC_COMP_V1 &&
+           v1->lmm_magic != LOV_USER_MAGIC_SPECIFIC)
                RETURN(-ENOTSUPP);
 
        if (v1->lmm_magic == LOV_MAGIC_COMP_V1) {
@@ -3598,9 +4446,11 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
                comp_cnt = comp_v1->lcm_entry_count;
                if (comp_cnt == 0)
                        RETURN(-EINVAL);
+               mirror_cnt = comp_v1->lcm_mirror_count + 1;
                composite = true;
        } else {
                comp_cnt = 1;
+               mirror_cnt = 0;
                composite = false;
        }
 
@@ -3610,11 +4460,11 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
                RETURN(rc);
 
        lds->lds_def_comp_cnt = comp_cnt;
-       lds->lds_def_striping_is_composite = composite ? 1 : 0;
+       lds->lds_def_striping_is_composite = composite;
+       lds->lds_def_mirror_cnt = mirror_cnt;
 
        for (i = 0; i < comp_cnt; i++) {
                struct lod_layout_component *lod_comp;
-               struct lu_extent *ext;
                char *pool;
 
                lod_comp = &lds->lds_def_comp_entries[i];
@@ -3628,11 +4478,16 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
                if (composite) {
                        v1 = (struct lov_user_md *)((char *)comp_v1 +
                                        comp_v1->lcm_entries[i].lcme_offset);
-                       ext = &comp_v1->lcm_entries[i].lcme_extent;
-                       lod_comp->llc_extent = *ext;
+                       lod_comp->llc_extent =
+                                       comp_v1->lcm_entries[i].lcme_extent;
+                       /* We only inherit certain flags from the layout */
+                       lod_comp->llc_flags =
+                                       comp_v1->lcm_entries[i].lcme_flags &
+                                       LCME_TEMPLATE_FLAGS;
                }
 
                if (v1->lmm_pattern != LOV_PATTERN_RAID0 &&
+                   v1->lmm_pattern != LOV_PATTERN_MDT &&
                    v1->lmm_pattern != 0) {
                        lod_free_def_comp_entries(lds);
                        RETURN(-EINVAL);
@@ -3647,6 +4502,7 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
                lod_comp->llc_stripe_count = v1->lmm_stripe_count;
                lod_comp->llc_stripe_size = v1->lmm_stripe_size;
                lod_comp->llc_stripe_offset = v1->lmm_stripe_offset;
+               lod_comp->llc_pattern = v1->lmm_pattern;
 
                pool = NULL;
                if (v1->lmm_magic == LOV_USER_MAGIC_V3) {
@@ -3656,6 +4512,17 @@ static int lod_get_default_lov_striping(const struct lu_env *env,
                                pool = v3->lmm_pool_name;
                }
                lod_set_def_pool(lds, i, pool);
+               if (v1->lmm_magic == LOV_USER_MAGIC_SPECIFIC) {
+                       v3 = (struct lov_user_md_v3 *)v1;
+                       rc = lod_comp_copy_ost_lists(lod_comp, v3);
+                       if (rc)
+                               RETURN(rc);
+               } else if (lod_comp->llc_ostlist.op_array &&
+                          lod_comp->llc_ostlist.op_count) {
+                       for (j = 0; j < lod_comp->llc_ostlist.op_count; j++)
+                               lod_comp->llc_ostlist.op_array[j] = -1;
+                       lod_comp->llc_ostlist.op_count = 0;
+               }
        }
 
        lds->lds_def_striping_set = 1;
@@ -3744,11 +4611,14 @@ static void lod_striping_from_default(struct lod_object *lo,
        int i, rc;
 
        if (lds->lds_def_striping_set && S_ISREG(mode)) {
-               rc = lod_alloc_comp_entries(lo, lds->lds_def_comp_cnt);
+               rc = lod_alloc_comp_entries(lo, lds->lds_def_mirror_cnt,
+                                           lds->lds_def_comp_cnt);
                if (rc != 0)
                        return;
 
                lo->ldo_is_composite = lds->lds_def_striping_is_composite;
+               if (lds->lds_def_mirror_cnt > 1)
+                       lo->ldo_flr_state = LCM_FL_RDONLY;
 
                for (i = 0; i < lo->ldo_comp_cnt; i++) {
                        struct lod_layout_component *obj_comp =
@@ -3756,11 +4626,13 @@ static void lod_striping_from_default(struct lod_object *lo,
                        struct lod_layout_component *def_comp =
                                                &lds->lds_def_comp_entries[i];
 
-                       CDEBUG(D_LAYOUT, "Inherite from default: size:%hu "
-                              "nr:%u offset:%u %s\n",
+                       CDEBUG(D_LAYOUT, "Inherit from default: flags=%#x "
+                              "size=%hu nr=%u offset=%u pattern=%#x pool=%s\n",
+                              def_comp->llc_flags,
                               def_comp->llc_stripe_size,
                               def_comp->llc_stripe_count,
                               def_comp->llc_stripe_offset,
+                              def_comp->llc_pattern,
                               def_comp->llc_pool ?: "");
 
                        *obj_comp = *def_comp;
@@ -3770,6 +4642,20 @@ static void lod_striping_from_default(struct lod_object *lo,
                                lod_obj_set_pool(lo, i, def_comp->llc_pool);
                        }
 
+                       /* copy ost list */
+                       if (def_comp->llc_ostlist.op_array &&
+                           def_comp->llc_ostlist.op_count) {
+                               OBD_ALLOC(obj_comp->llc_ostlist.op_array,
+                                         obj_comp->llc_ostlist.op_size);
+                               if (!obj_comp->llc_ostlist.op_array)
+                                       return;
+                               memcpy(obj_comp->llc_ostlist.op_array,
+                                      def_comp->llc_ostlist.op_array,
+                                      obj_comp->llc_ostlist.op_size);
+                       } else if (def_comp->llc_ostlist.op_array) {
+                               obj_comp->llc_ostlist.op_array = NULL;
+                       }
+
                        /*
                         * Don't initialize these fields for plain layout
                         * (v1/v3) here, they are inherited in the order of
@@ -3781,12 +4667,7 @@ static void lod_striping_from_default(struct lod_object *lo,
                        if (!lo->ldo_is_composite)
                                continue;
 
-                       if (obj_comp->llc_stripe_count <= 0)
-                               obj_comp->llc_stripe_count =
-                                       desc->ld_default_stripe_count;
-                       if (obj_comp->llc_stripe_size <= 0)
-                               obj_comp->llc_stripe_size =
-                                       desc->ld_default_stripe_size;
+                       lod_adjust_stripe_info(obj_comp, desc);
                }
        } else if (lds->lds_dir_def_striping_set && S_ISDIR(mode)) {
                if (lo->ldo_dir_stripe_count == 0)
@@ -3877,6 +4758,8 @@ static void lod_ah_init(const struct lu_env *env,
                nextc->do_ops->do_ah_init(env, ah, nextp, nextc, child_mode);
 
        if (S_ISDIR(child_mode)) {
+               const struct lmv_user_md_v1 *lum1 = ah->dah_eadata;
+
                /* other default values are 0 */
                lc->ldo_dir_stripe_offset = -1;
 
@@ -3889,10 +4772,13 @@ static void lod_ah_init(const struct lu_env *env,
                        lc->ldo_def_striping = lds;
 
                /* It should always honour the specified stripes */
+               /* Note: old client (< 2.7)might also do lfs mkdir, whose EA
+                * will have old magic. In this case, we should ignore the
+                * stripe count and try to create dir by default stripe.
+                */
                if (ah->dah_eadata != NULL && ah->dah_eadata_len != 0 &&
-                   lod_verify_md_striping(d, ah->dah_eadata) == 0) {
-                       const struct lmv_user_md_v1 *lum1 = ah->dah_eadata;
-
+                   (le32_to_cpu(lum1->lum_magic) == LMV_USER_MAGIC ||
+                    le32_to_cpu(lum1->lum_magic) == LMV_USER_MAGIC_SPECIFIC)) {
                        lc->ldo_dir_stripe_count =
                                le32_to_cpu(lum1->lum_stripe_count);
                        lc->ldo_dir_stripe_offset =
@@ -3907,19 +4793,19 @@ static void lod_ah_init(const struct lu_env *env,
                } else {
                        /* transfer defaults LMV to new directory */
                        lod_striping_from_default(lc, lds, child_mode);
+
+                       /* set count 0 to create normal directory */
+                       if (lc->ldo_dir_stripe_count == 1)
+                               lc->ldo_dir_stripe_count = 0;
                }
 
                /* shrink the stripe_count to the avaible MDT count */
                if (lc->ldo_dir_stripe_count > d->lod_remote_mdt_count + 1 &&
-                   !OBD_FAIL_CHECK(OBD_FAIL_LARGE_STRIPE))
+                   !OBD_FAIL_CHECK(OBD_FAIL_LARGE_STRIPE)) {
                        lc->ldo_dir_stripe_count = d->lod_remote_mdt_count + 1;
-
-               /* Directory will be striped only if stripe_count > 1, if
-                * stripe_count == 1, let's reset stripe_count = 0 to avoid
-                * create single master stripe and also help to unify the
-                * stripe handling of directories and files */
-               if (lc->ldo_dir_stripe_count == 1)
-                       lc->ldo_dir_stripe_count = 0;
+                       if (lc->ldo_dir_stripe_count == 1)
+                               lc->ldo_dir_stripe_count = 0;
+               }
 
                CDEBUG(D_INFO, "final dir stripe [%hu %d %u]\n",
                       lc->ldo_dir_stripe_count,
@@ -4001,9 +4887,8 @@ out:
         * in config log, use them.
         */
        if (lod_need_inherit_more(lc, false)) {
-
                if (lc->ldo_comp_cnt == 0) {
-                       rc = lod_alloc_comp_entries(lc, 1);
+                       rc = lod_alloc_comp_entries(lc, 0, 1);
                        if (rc)
                                /* fail to allocate memory, will create a
                                 * non-striped file. */
@@ -4015,12 +4900,7 @@ out:
                LASSERT(!lc->ldo_is_composite);
                lod_comp = &lc->ldo_comp_entries[0];
                desc = &d->lod_desc;
-               if (lod_comp->llc_stripe_count <= 0)
-                       lod_comp->llc_stripe_count =
-                               desc->ld_default_stripe_count;
-               if (lod_comp->llc_stripe_size <= 0)
-                       lod_comp->llc_stripe_size =
-                               desc->ld_default_stripe_size;
+               lod_adjust_stripe_info(lod_comp, desc);
        }
 
        EXIT;
@@ -4052,6 +4932,7 @@ static int lod_declare_init_size(const struct lu_env *env,
        struct lu_attr  *attr = &lod_env_info(env)->lti_attr;
        uint64_t        size, offs;
        int     i, rc, stripe, stripe_count = 0, stripe_size = 0;
+       struct lu_extent size_ext;
        ENTRY;
 
        if (!lod_obj_is_striped(dt))
@@ -4066,6 +4947,7 @@ static int lod_declare_init_size(const struct lu_env *env,
        if (size == 0)
                RETURN(0);
 
+       size_ext = (typeof(size_ext)){ .e_start = size - 1, .e_end = size };
        for (i = 0; i < lo->ldo_comp_cnt; i++) {
                struct lod_layout_component *lod_comp;
                struct lu_extent *extent;
@@ -4076,35 +4958,34 @@ static int lod_declare_init_size(const struct lu_env *env,
                        continue;
 
                extent = &lod_comp->llc_extent;
-               CDEBUG(D_INFO, "%lld [%lld, %lld)\n",
-                      size, extent->e_start, extent->e_end);
+               CDEBUG(D_INFO, "%lld "DEXT"\n", size, PEXT(extent));
                if (!lo->ldo_is_composite ||
-                   (size >= extent->e_start && size < extent->e_end)) {
+                   lu_extent_is_overlapped(extent, &size_ext)) {
                        objects = lod_comp->llc_stripe;
                        stripe_count = lod_comp->llc_stripe_count;
                        stripe_size = lod_comp->llc_stripe_size;
-                       break;
-               }
-       }
-
-       if (stripe_count == 0)
-               RETURN(0);
 
-       LASSERT(objects != NULL && stripe_size != 0);
+                       /* next mirror */
+                       if (stripe_count == 0)
+                               continue;
 
-       /* ll_do_div64(a, b) returns a % b, and a = a / b */
-       ll_do_div64(size, (__u64)stripe_size);
-       stripe = ll_do_div64(size, (__u64)stripe_count);
-       LASSERT(objects[stripe] != NULL);
+                       LASSERT(objects != NULL && stripe_size != 0);
+                       /* ll_do_div64(a, b) returns a % b, and a = a / b */
+                       ll_do_div64(size, (__u64)stripe_size);
+                       stripe = ll_do_div64(size, (__u64)stripe_count);
+                       LASSERT(objects[stripe] != NULL);
 
-       size = size * stripe_size;
-       offs = attr->la_size;
-       size += ll_do_div64(offs, stripe_size);
+                       size = size * stripe_size;
+                       offs = attr->la_size;
+                       size += ll_do_div64(offs, stripe_size);
 
-       attr->la_valid = LA_SIZE;
-       attr->la_size = size;
+                       attr->la_valid = LA_SIZE;
+                       attr->la_size = size;
 
-       rc = lod_sub_declare_attr_set(env, objects[stripe], attr, th);
+                       rc = lod_sub_declare_attr_set(env, objects[stripe],
+                                                     attr, th);
+               }
+       }
 
        RETURN(rc);
 }
@@ -4178,7 +5059,7 @@ out:
        /* failed to create striping or to set initial size, let's reset
         * config so that others don't get confused */
        if (rc)
-               lod_object_free_striping(env, lo);
+               lod_striping_free(env, lo);
 
        RETURN(rc);
 }
@@ -4228,6 +5109,8 @@ static int lod_declare_create(const struct lu_env *env, struct dt_object *dt,
                                                        NULL, th);
        } else if (dof->dof_type == DFT_DIR) {
                struct seq_server_site *ss;
+               struct lu_buf buf = { NULL };
+               struct lu_buf *lmu = NULL;
 
                ss = lu_site2seq(dt->do_lu.lo_dev->ld_site);
 
@@ -4277,58 +5160,138 @@ static int lod_declare_create(const struct lu_env *env, struct dt_object *dt,
                                else
                                        GOTO(out, rc = -EINVAL);
                        }
+               } else if (hint && hint->dah_eadata) {
+                       lmu = &buf;
+                       lmu->lb_buf = (void *)hint->dah_eadata;
+                       lmu->lb_len = hint->dah_eadata_len;
                }
 
-               rc = lod_declare_dir_striping_create(env, dt, attr, dof, th);
+               rc = lod_declare_dir_striping_create(env, dt, attr, lmu, dof,
+                                                    th);
        }
 out:
        /* failed to create striping or to set initial size, let's reset
         * config so that others don't get confused */
        if (rc)
-               lod_object_free_striping(env, lo);
+               lod_striping_free(env, lo);
        RETURN(rc);
 }
 
 /**
- * Creation of a striped regular object.
- *
- * The function is called to create the stripe objects for a regular
- * striped file. This can happen at the initial object creation or
- * when the caller asks LOD to do so using ->do_xattr_set() method
- * (so called late striping). Notice all the information are already
- * prepared in the form of the list of objects (ldo_stripe field).
- * This is done during declare phase.
+ * Generate component ID for new created component.
  *
- * \param[in] env      execution environment
- * \param[in] dt       object
- * \param[in] attr     attributes the stripes will be created with
- * \param[in] dof      format of stripes (see OSD API description)
- * \param[in] th       transaction handle
+ * \param[in] lo               LOD object
+ * \param[in] comp_idx         index of ldo_comp_entries
  *
- * \retval             0 on success
- * \retval             negative if failed
+ * \retval                     component ID on success
+ * \retval                     LCME_ID_INVAL on failure
  */
-int lod_striped_create(const struct lu_env *env, struct dt_object *dt,
-                      struct lu_attr *attr, struct dt_object_format *dof,
+static __u32 lod_gen_component_id(struct lod_object *lo,
+                                 int mirror_id, int comp_idx)
+{
+       struct lod_layout_component *lod_comp;
+       __u32   id, start, end;
+       int     i;
+
+       LASSERT(lo->ldo_comp_entries[comp_idx].llc_id == LCME_ID_INVAL);
+
+       lod_obj_inc_layout_gen(lo);
+       id = lo->ldo_layout_gen;
+       if (likely(id <= SEQ_ID_MAX))
+               RETURN(pflr_id(mirror_id, id & SEQ_ID_MASK));
+
+       /* Layout generation wraps, need to check collisions. */
+       start = id & SEQ_ID_MASK;
+       end = SEQ_ID_MAX;
+again:
+       for (id = start; id <= end; id++) {
+               for (i = 0; i < lo->ldo_comp_cnt; i++) {
+                       lod_comp = &lo->ldo_comp_entries[i];
+                       if (pflr_id(mirror_id, id) == lod_comp->llc_id)
+                               break;
+               }
+               /* Found the ununsed ID */
+               if (i == lo->ldo_comp_cnt)
+                       RETURN(pflr_id(mirror_id, id));
+       }
+       if (end == LCME_ID_MAX) {
+               start = 1;
+               end = min(lo->ldo_layout_gen & LCME_ID_MASK,
+                         (__u32)(LCME_ID_MAX - 1));
+               goto again;
+       }
+
+       RETURN(LCME_ID_INVAL);
+}
+
+/**
+ * Creation of a striped regular object.
+ *
+ * The function is called to create the stripe objects for a regular
+ * striped file. This can happen at the initial object creation or
+ * when the caller asks LOD to do so using ->do_xattr_set() method
+ * (so called late striping). Notice all the information are already
+ * prepared in the form of the list of objects (ldo_stripe field).
+ * This is done during declare phase.
+ *
+ * \param[in] env      execution environment
+ * \param[in] dt       object
+ * \param[in] attr     attributes the stripes will be created with
+ * \param[in] dof      format of stripes (see OSD API description)
+ * \param[in] th       transaction handle
+ *
+ * \retval             0 on success
+ * \retval             negative if failed
+ */
+int lod_striped_create(const struct lu_env *env, struct dt_object *dt,
+                      struct lu_attr *attr, struct dt_object_format *dof,
                       struct thandle *th)
 {
        struct lod_layout_component     *lod_comp;
        struct lod_object       *lo = lod_dt_obj(dt);
+       __u16   mirror_id;
        int     rc = 0, i, j;
        ENTRY;
 
        LASSERT(lo->ldo_comp_cnt != 0 && lo->ldo_comp_entries != NULL);
 
+       mirror_id = 0; /* non-flr file's mirror_id is 0 */
+       if (lo->ldo_mirror_count > 1) {
+               for (i = 0; i < lo->ldo_comp_cnt; i++) {
+                       lod_comp = &lo->ldo_comp_entries[i];
+                       if (lod_comp->llc_id != LCME_ID_INVAL &&
+                           mirror_id_of(lod_comp->llc_id) > mirror_id)
+                               mirror_id = mirror_id_of(lod_comp->llc_id);
+               }
+       }
+
        /* create all underlying objects */
        for (i = 0; i < lo->ldo_comp_cnt; i++) {
                lod_comp = &lo->ldo_comp_entries[i];
 
+               if (lod_comp->llc_id == LCME_ID_INVAL) {
+                       /* only the component of FLR layout with more than 1
+                        * mirror has mirror ID in its component ID.
+                        */
+                       if (lod_comp->llc_extent.e_start == 0 &&
+                           lo->ldo_mirror_count > 1)
+                               ++mirror_id;
+
+                       lod_comp->llc_id = lod_gen_component_id(lo,
+                                                               mirror_id, i);
+                       if (lod_comp->llc_id == LCME_ID_INVAL)
+                               GOTO(out, rc = -ERANGE);
+               }
+
                if (lod_comp_inited(lod_comp))
                        continue;
 
                if (lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED)
                        lod_comp_set_init(lod_comp);
 
+               if (lov_pattern(lod_comp->llc_pattern) == LOV_PATTERN_MDT)
+                       lod_comp_set_init(lod_comp);
+
                if (lod_comp->llc_stripe == NULL)
                        continue;
 
@@ -4338,22 +5301,44 @@ int lod_striped_create(const struct lu_env *env, struct dt_object *dt,
                        LASSERT(object != NULL);
                        rc = lod_sub_create(env, object, attr, NULL, dof, th);
                        if (rc)
-                               break;
+                               GOTO(out, rc);
                }
                lod_comp_set_init(lod_comp);
        }
 
-       if (rc == 0)
-               rc = lod_generate_and_set_lovea(env, lo, th);
+       rc = lod_fill_mirrors(lo);
+       if (rc)
+               GOTO(out, rc);
 
-       if (rc == 0)
-               lo->ldo_comp_cached = 1;
-       else
-               lod_object_free_striping(env, lo);
+       rc = lod_generate_and_set_lovea(env, lo, th);
+       if (rc)
+               GOTO(out, rc);
 
+       lo->ldo_comp_cached = 1;
+       RETURN(0);
+
+out:
+       lod_striping_free(env, lo);
        RETURN(rc);
 }
 
+static inline bool lod_obj_is_dom(struct dt_object *dt)
+{
+       struct lod_object *lo = lod_dt_obj(dt);
+
+       if (!dt_object_exists(dt_object_child(dt)))
+               return false;
+
+       if (S_ISDIR(dt->do_lu.lo_header->loh_attr))
+               return false;
+
+       if (!lo->ldo_comp_cnt)
+               return false;
+
+       return (lov_pattern(lo->ldo_comp_entries[0].llc_pattern) ==
+               LOV_PATTERN_MDT);
+}
+
 /**
  * Implementation of dt_object_operations::do_create.
  *
@@ -4376,7 +5361,8 @@ static int lod_create(const struct lu_env *env, struct dt_object *dt,
                RETURN(rc);
 
        if (S_ISREG(dt->do_lu.lo_header->loh_attr) &&
-           lod_obj_is_striped(dt) && dof->u.dof_reg.striped != 0) {
+           (lod_obj_is_striped(dt) || lod_obj_is_dom(dt)) &&
+           dof->u.dof_reg.striped != 0) {
                LASSERT(lod_dt_obj(dt)->ldo_comp_cached == 0);
                rc = lod_striped_create(env, dt, attr, dof, th);
        }
@@ -4387,7 +5373,8 @@ static int lod_create(const struct lu_env *env, struct dt_object *dt,
 static inline int
 lod_obj_stripe_destroy_cb(const struct lu_env *env, struct lod_object *lo,
                          struct dt_object *dt, struct thandle *th,
-                         int stripe_idx, struct lod_obj_stripe_cb_data *data)
+                         int comp_idx, int stripe_idx,
+                         struct lod_obj_stripe_cb_data *data)
 {
        if (data->locd_declare)
                return lod_sub_declare_destroy(env, dt, th);
@@ -4424,7 +5411,7 @@ static int lod_declare_destroy(const struct lu_env *env, struct dt_object *dt,
         * is being initialized as we don't need this information till
         * few specific cases like destroy, chown
         */
-       rc = lod_load_striping(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc)
                RETURN(rc);
 
@@ -4479,11 +5466,11 @@ static int lod_declare_destroy(const struct lu_env *env, struct dt_object *dt,
                                break;
                }
        } else {
-               struct lod_obj_stripe_cb_data data;
+               struct lod_obj_stripe_cb_data data = { { 0 } };
 
                data.locd_declare = true;
-               rc = lod_obj_for_each_stripe(env, lo, th,
-                               lod_obj_stripe_destroy_cb, &data);
+               data.locd_stripe_cb = lod_obj_stripe_destroy_cb;
+               rc = lod_obj_for_each_stripe(env, lo, th, &data);
        }
 
        RETURN(rc);
@@ -4569,11 +5556,11 @@ static int lod_destroy(const struct lu_env *env, struct dt_object *dt,
                        }
                }
        } else {
-               struct lod_obj_stripe_cb_data data;
+               struct lod_obj_stripe_cb_data data = { { 0 } };
 
                data.locd_declare = false;
-               rc = lod_obj_for_each_stripe(env, lo, th,
-                               lod_obj_stripe_destroy_cb, &data);
+               data.locd_stripe_cb = lod_obj_stripe_destroy_cb;
+               rc = lod_obj_for_each_stripe(env, lo, th, &data);
        }
 
        RETURN(rc);
@@ -4638,42 +5625,6 @@ static int lod_object_sync(const struct lu_env *env, struct dt_object *dt,
 }
 
 /**
- * Release LDLM locks on the stripes of a striped directory.
- *
- * Iterates over all the locks taken on the stripe objects and
- * cancel them.
- *
- * \param[in] env      execution environment
- * \param[in] dt       striped object
- * \param[in] einfo    lock description
- * \param[in] policy   data describing requested lock
- *
- * \retval             0 on success
- * \retval             negative if failed
- */
-static int lod_object_unlock_internal(const struct lu_env *env,
-                                     struct dt_object *dt,
-                                     struct ldlm_enqueue_info *einfo,
-                                     union ldlm_policy_data *policy)
-{
-       struct lustre_handle_array *slave_locks = einfo->ei_cbdata;
-       int                     rc = 0;
-       int                     i;
-       ENTRY;
-
-       if (slave_locks == NULL)
-               RETURN(0);
-
-       for (i = 1; i < slave_locks->count; i++) {
-               if (lustre_handle_is_used(&slave_locks->handles[i]))
-                       ldlm_lock_decref_and_cancel(&slave_locks->handles[i],
-                                                   einfo->ei_mode);
-       }
-
-       RETURN(rc);
-}
-
-/**
  * Implementation of dt_object_operations::do_object_unlock.
  *
  * Used to release LDLM lock(s).
@@ -4695,19 +5646,23 @@ static int lod_object_unlock(const struct lu_env *env, struct dt_object *dt,
                RETURN(0);
 
        LASSERT(S_ISDIR(dt->do_lu.lo_header->loh_attr));
-       LASSERT(lo->ldo_dir_stripe_count > 1);
        /* Note: for remote lock for single stripe dir, MDT will cancel
         * the lock by lockh directly */
        LASSERT(!dt_object_remote(dt_object_child(dt)));
 
        /* locks were unlocked in MDT layer */
-       for (i = 1; i < slave_locks->count; i++) {
-               LASSERT(!lustre_handle_is_used(&slave_locks->handles[i]));
+       for (i = 0; i < slave_locks->ha_count; i++)
+               LASSERT(!lustre_handle_is_used(&slave_locks->ha_handles[i]));
+
+       /*
+        * NB, ha_count may not equal to ldo_dir_stripe_count, because dir
+        * layout may change, e.g., shrink dir layout after migration.
+        */
+       for (i = 0; i < lo->ldo_dir_stripe_count; i++)
                dt_invalidate(env, lo->ldo_stripe[i]);
-       }
 
-       slave_locks_size = sizeof(*slave_locks) + slave_locks->count *
-                          sizeof(slave_locks->handles[0]);
+       slave_locks_size = offsetof(typeof(*slave_locks),
+                                   ha_handles[slave_locks->ha_count]);
        OBD_FREE(slave_locks, slave_locks_size);
        einfo->ei_cbdata = NULL;
 
@@ -4728,11 +5683,11 @@ static int lod_object_lock(const struct lu_env *env,
                           struct ldlm_enqueue_info *einfo,
                           union ldlm_policy_data *policy)
 {
-       struct lod_object       *lo = lod_dt_obj(dt);
-       int                     rc = 0;
-       int                     i;
-       int                     slave_locks_size;
+       struct lod_object *lo = lod_dt_obj(dt);
+       int slave_locks_size;
        struct lustre_handle_array *slave_locks = NULL;
+       int i;
+       int rc;
        ENTRY;
 
        /* remote object lock */
@@ -4743,35 +5698,28 @@ static int lod_object_lock(const struct lu_env *env,
        }
 
        if (!S_ISDIR(dt->do_lu.lo_header->loh_attr))
-               GOTO(out, rc = -ENOTDIR);
+               RETURN(-ENOTDIR);
 
-       rc = lod_load_striping(env, lo);
+       rc = lod_striping_load(env, lo);
        if (rc != 0)
-               GOTO(out, rc);
+               RETURN(rc);
 
        /* No stripes */
-       if (lo->ldo_dir_stripe_count <= 1) {
-               /*
-                * NB, ei_cbdata stores pointer to slave locks, if no locks
-                * taken, make sure it's set to NULL, otherwise MDT will try to
-                * unlock them.
-                */
-               einfo->ei_cbdata = NULL;
-               GOTO(out, rc = 0);
-       }
+       if (lo->ldo_dir_stripe_count <= 1)
+               RETURN(0);
 
-       slave_locks_size = sizeof(*slave_locks) + lo->ldo_dir_stripe_count *
-                          sizeof(slave_locks->handles[0]);
+       slave_locks_size = offsetof(typeof(*slave_locks),
+                                   ha_handles[lo->ldo_dir_stripe_count]);
        /* Freed in lod_object_unlock */
        OBD_ALLOC(slave_locks, slave_locks_size);
-       if (slave_locks == NULL)
-               GOTO(out, rc = -ENOMEM);
-       slave_locks->count = lo->ldo_dir_stripe_count;
+       if (!slave_locks)
+               RETURN(-ENOMEM);
+       slave_locks->ha_count = lo->ldo_dir_stripe_count;
 
        /* striped directory lock */
-       for (i = 1; i < lo->ldo_dir_stripe_count; i++) {
-               struct lustre_handle    lockh;
-               struct ldlm_res_id      *res_id;
+       for (i = 0; i < lo->ldo_dir_stripe_count; i++) {
+               struct lustre_handle lockh;
+               struct ldlm_res_id *res_id;
 
                res_id = &lod_env_info(env)->lti_res_id;
                fid_build_reg_res_name(lu_object_fid(&lo->ldo_stripe[i]->do_lu),
@@ -4779,46 +5727,41 @@ static int lod_object_lock(const struct lu_env *env,
                einfo->ei_res_id = res_id;
 
                LASSERT(lo->ldo_stripe[i] != NULL);
-               if (likely(dt_object_remote(lo->ldo_stripe[i]))) {
+               if (dt_object_remote(lo->ldo_stripe[i])) {
+                       set_bit(i, (void *)slave_locks->ha_map);
                        rc = dt_object_lock(env, lo->ldo_stripe[i], &lockh,
                                            einfo, policy);
                } else {
                        struct ldlm_namespace *ns = einfo->ei_namespace;
                        ldlm_blocking_callback blocking = einfo->ei_cb_local_bl;
                        ldlm_completion_callback completion = einfo->ei_cb_cp;
-                       __u64   dlmflags = LDLM_FL_ATOMIC_CB;
+                       __u64 dlmflags = LDLM_FL_ATOMIC_CB;
 
                        if (einfo->ei_mode == LCK_PW ||
                            einfo->ei_mode == LCK_EX)
                                dlmflags |= LDLM_FL_COS_INCOMPAT;
 
-                       /* This only happens if there are mulitple stripes
-                        * on the master MDT, i.e. except stripe0, there are
-                        * other stripes on the Master MDT as well, Only
-                        * happens in the test case right now. */
                        LASSERT(ns != NULL);
-                       rc = ldlm_cli_enqueue_local(ns, res_id, LDLM_IBITS,
+                       rc = ldlm_cli_enqueue_local(env, ns, res_id, LDLM_IBITS,
                                                    policy, einfo->ei_mode,
                                                    &dlmflags, blocking,
                                                    completion, NULL,
                                                    NULL, 0, LVB_T_NONE,
                                                    NULL, &lockh);
                }
-               if (rc != 0)
-                       break;
-               slave_locks->handles[i] = lockh;
+               if (rc) {
+                       while (i--)
+                               ldlm_lock_decref_and_cancel(
+                                               &slave_locks->ha_handles[i],
+                                               einfo->ei_mode);
+                       OBD_FREE(slave_locks, slave_locks_size);
+                       RETURN(rc);
+               }
+               slave_locks->ha_handles[i] = lockh;
        }
        einfo->ei_cbdata = slave_locks;
 
-       if (rc != 0 && slave_locks != NULL) {
-               lod_object_unlock_internal(env, dt, einfo, policy);
-               OBD_FREE(slave_locks, slave_locks_size);
-       }
-       EXIT;
-out:
-       if (rc != 0)
-               einfo->ei_cbdata = NULL;
-       RETURN(rc);
+       RETURN(0);
 }
 
 /**
@@ -4831,29 +5774,71 @@ static int lod_invalidate(const struct lu_env *env, struct dt_object *dt)
        return dt_invalidate(env, dt_object_child(dt));
 }
 
-static int lod_declare_layout_change(const struct lu_env *env,
-                                    struct dt_object *dt,
-                                    struct layout_intent *layout,
-                                    const struct lu_buf *buf,
-                                    struct thandle *th)
+static int lod_layout_data_init(struct lod_thread_info *info, __u32 comp_cnt)
 {
-       struct lod_thread_info  *info = lod_env_info(env);
-       struct lod_object *lo = lod_dt_obj(dt);
-       struct lod_device *d = lu2lod_dev(dt->do_lu.lo_dev);
-       struct dt_object *next = dt_object_child(dt);
-       struct ost_pool *inuse = &info->lti_inuse_osts;
+       ENTRY;
+
+       /* clear memory region that will be used for layout change */
+       memset(&info->lti_layout_attr, 0, sizeof(struct lu_attr));
+       info->lti_count = 0;
+
+       if (info->lti_comp_size >= comp_cnt)
+               RETURN(0);
+
+       if (info->lti_comp_size > 0) {
+               OBD_FREE(info->lti_comp_idx,
+                        info->lti_comp_size * sizeof(__u32));
+               info->lti_comp_size = 0;
+       }
+
+       OBD_ALLOC(info->lti_comp_idx, comp_cnt * sizeof(__u32));
+       if (!info->lti_comp_idx)
+               RETURN(-ENOMEM);
+
+       info->lti_comp_size = comp_cnt;
+       RETURN(0);
+}
+
+static int lod_declare_instantiate_components(const struct lu_env *env,
+               struct lod_object *lo, struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       int i;
+       int rc = 0;
+       ENTRY;
+
+       LASSERT(info->lti_count < lo->ldo_comp_cnt);
+
+       for (i = 0; i < info->lti_count; i++) {
+               rc = lod_qos_prep_create(env, lo, NULL, th,
+                                        info->lti_comp_idx[i]);
+               if (rc)
+                       break;
+       }
+
+       if (!rc) {
+               info->lti_buf.lb_len = lod_comp_md_size(lo, false);
+               rc = lod_sub_declare_xattr_set(env, lod_object_child(lo),
+                               &info->lti_buf, XATTR_NAME_LOV, 0, th);
+       }
+
+       RETURN(rc);
+}
+
+static int lod_declare_update_plain(const struct lu_env *env,
+               struct lod_object *lo, struct layout_intent *layout,
+               const struct lu_buf *buf, struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lod_device *d = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
        struct lod_layout_component *lod_comp;
        struct lov_comp_md_v1 *comp_v1 = NULL;
        bool replay = false;
-       bool need_create = false;
        int i, rc;
        ENTRY;
 
-       if (!S_ISREG(dt->do_lu.lo_header->loh_attr) || !dt_object_exists(dt) ||
-           dt_object_remote(next))
-               RETURN(-EINVAL);
+       LASSERT(lo->ldo_flr_state == LCM_FL_NONE);
 
-       dt_write_lock(env, next, 0);
        /*
         * In case the client is passing lovea, which only happens during
         * the replay of layout intent write RPC for now, we may need to
@@ -4862,9 +5847,9 @@ static int lod_declare_layout_change(const struct lu_env *env,
        if (buf && buf->lb_len)  {
                struct lov_user_md_v1 *v1 = buf->lb_buf;
 
-               if (v1->lmm_magic != (LOV_MAGIC_DEF | LOV_MAGIC_COMP_V1) &&
-                   v1->lmm_magic !=
-                               __swab32(LOV_MAGIC_DEF | LOV_MAGIC_COMP_V1)) {
+               if (v1->lmm_magic != (LOV_MAGIC_DEFINED | LOV_MAGIC_COMP_V1) &&
+                   v1->lmm_magic != __swab32(LOV_MAGIC_DEFINED |
+                                             LOV_MAGIC_COMP_V1)) {
                        CERROR("%s: the replay buffer of layout extend "
                               "(magic %#x) does not contain expected "
                               "composite layout.\n",
@@ -4872,25 +5857,20 @@ static int lod_declare_layout_change(const struct lu_env *env,
                        GOTO(out, rc = -EINVAL);
                }
 
-               lod_object_free_striping(env, lo);
                rc = lod_use_defined_striping(env, lo, buf);
                if (rc)
                        GOTO(out, rc);
+               lo->ldo_comp_cached = 1;
 
                rc = lod_get_lov_ea(env, lo);
                if (rc <= 0)
                        GOTO(out, rc);
                /* old on-disk EA is stored in info->lti_buf */
-               comp_v1 = (struct lov_comp_md_v1 *)&info->lti_buf.lb_buf;
+               comp_v1 = (struct lov_comp_md_v1 *)info->lti_buf.lb_buf;
                replay = true;
        } else {
                /* non replay path */
-               rc = lod_load_striping_locked(env, lo);
-               if (rc)
-                       GOTO(out, rc);
-
-               /* Prepare inuse array for composite file */
-               rc = lod_prepare_inuse(env, lo);
+               rc = lod_striping_load(env, lo);
                if (rc)
                        GOTO(out, rc);
        }
@@ -4899,15 +5879,19 @@ static int lod_declare_layout_change(const struct lu_env *env,
        lod_comp = &lo->ldo_comp_entries[lo->ldo_comp_cnt - 1];
        if (lo->ldo_comp_cnt > 1 &&
            lod_comp->llc_extent.e_end != OBD_OBJECT_EOF &&
-           lod_comp->llc_extent.e_end < layout->li_end) {
+           lod_comp->llc_extent.e_end < layout->li_extent.e_end) {
                CDEBUG(replay ? D_ERROR : D_LAYOUT,
                       "%s: the defined layout [0, %#llx) does not covers "
-                      "the write range [%#llx, %#llx).\n",
+                      "the write range "DEXT"\n",
                       lod2obd(d)->obd_name, lod_comp->llc_extent.e_end,
-                      layout->li_start, layout->li_end);
+                      PEXT(&layout->li_extent));
                GOTO(out, rc = -EINVAL);
        }
 
+       CDEBUG(D_LAYOUT, "%s: "DFID": instantiate components "DEXT"\n",
+              lod2obd(d)->obd_name, PFID(lod_object_fid(lo)),
+              PEXT(&layout->li_extent));
+
        /*
         * Iterate ld->ldo_comp_entries, find the component whose extent under
         * the write range and not instantianted.
@@ -4915,7 +5899,7 @@ static int lod_declare_layout_change(const struct lu_env *env,
        for (i = 0; i < lo->ldo_comp_cnt; i++) {
                lod_comp = &lo->ldo_comp_entries[i];
 
-               if (lod_comp->llc_extent.e_start >= layout->li_end)
+               if (lod_comp->llc_extent.e_start >= layout->li_extent.e_end)
                        break;
 
                if (!replay) {
@@ -4941,30 +5925,683 @@ static int lod_declare_layout_change(const struct lu_env *env,
                if (lod_comp->llc_pattern & LOV_PATTERN_F_RELEASED)
                        GOTO(out, rc = -EINVAL);
 
-               need_create = true;
+               LASSERT(info->lti_comp_idx != NULL);
+               info->lti_comp_idx[info->lti_count++] = i;
+       }
+
+       if (info->lti_count == 0)
+               RETURN(-EALREADY);
 
-               rc = lod_qos_prep_create(env, lo, NULL, th, i, inuse);
-               if (rc)
+       lod_obj_inc_layout_gen(lo);
+       rc = lod_declare_instantiate_components(env, lo, th);
+out:
+       if (rc)
+               lod_striping_free(env, lo);
+       RETURN(rc);
+}
+
+static inline int lod_comp_index(struct lod_object *lo,
+                                struct lod_layout_component *lod_comp)
+{
+       LASSERT(lod_comp >= lo->ldo_comp_entries &&
+               lod_comp <= &lo->ldo_comp_entries[lo->ldo_comp_cnt - 1]);
+
+       return lod_comp - lo->ldo_comp_entries;
+}
+
+/**
+ * Stale other mirrors by writing extent.
+ */
+static void lod_stale_components(struct lod_object *lo, int primary,
+                                struct lu_extent *extent)
+{
+       struct lod_layout_component *pri_comp, *lod_comp;
+       int i;
+
+       /* The writing extent decides which components in the primary
+        * are affected... */
+       CDEBUG(D_LAYOUT, "primary mirror %d, "DEXT"\n", primary, PEXT(extent));
+       lod_foreach_mirror_comp(pri_comp, lo, primary) {
+               if (!lu_extent_is_overlapped(extent, &pri_comp->llc_extent))
+                       continue;
+
+               CDEBUG(D_LAYOUT, "primary comp %u "DEXT"\n",
+                      lod_comp_index(lo, pri_comp),
+                      PEXT(&pri_comp->llc_extent));
+
+               for (i = 0; i < lo->ldo_mirror_count; i++) {
+                       if (i == primary)
+                               continue;
+
+                       /* ... and then stale other components that are
+                        * overlapping with primary components */
+                       lod_foreach_mirror_comp(lod_comp, lo, i) {
+                               if (!lu_extent_is_overlapped(
+                                                       &pri_comp->llc_extent,
+                                                       &lod_comp->llc_extent))
+                                       continue;
+
+                               CDEBUG(D_LAYOUT, "stale: %u / %u\n",
+                                     i, lod_comp_index(lo, lod_comp));
+
+                               lod_comp->llc_flags |= LCME_FL_STALE;
+                               lo->ldo_mirrors[i].lme_stale = 1;
+                       }
+               }
+       }
+}
+
+/**
+ * check an OST's availability
+ * \param[in] env      execution environment
+ * \param[in] lo       lod object
+ * \param[in] dt       dt object
+ * \param[in] index    mirror index
+ *
+ * \retval     negative if failed
+ * \retval     1 if \a dt is available
+ * \retval     0 if \a dt is not available
+ */
+static inline int lod_check_ost_avail(const struct lu_env *env,
+                                     struct lod_object *lo,
+                                     struct dt_object *dt, int index)
+{
+       struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
+       struct lod_tgt_desc *ost;
+       __u32 idx;
+       int type = LU_SEQ_RANGE_OST;
+       int rc;
+
+       rc = lod_fld_lookup(env, lod, lu_object_fid(&dt->do_lu), &idx, &type);
+       if (rc < 0) {
+               CERROR("%s: can't locate "DFID":rc = %d\n",
+                      lod2obd(lod)->obd_name, PFID(lu_object_fid(&dt->do_lu)),
+                      rc);
+               return rc;
+       }
+
+       ost = OST_TGT(lod, idx);
+       if (ost->ltd_statfs.os_state &
+               (OS_STATE_READONLY | OS_STATE_ENOSPC | OS_STATE_ENOINO |
+                OS_STATE_NOPRECREATE) ||
+           ost->ltd_active == 0) {
+               CDEBUG(D_LAYOUT, DFID ": mirror %d OST%d unavail, rc = %d\n",
+                      PFID(lod_object_fid(lo)), index, idx, rc);
+               return 0;
+       }
+
+       return 1;
+}
+
+/**
+ * Pick primary mirror for write
+ * \param[in] env      execution environment
+ * \param[in] lo       object
+ * \param[in] extent   write range
+ */
+static int lod_primary_pick(const struct lu_env *env, struct lod_object *lo,
+                           struct lu_extent *extent)
+{
+       struct lod_device *lod = lu2lod_dev(lo->ldo_obj.do_lu.lo_dev);
+       unsigned int seq = 0;
+       struct lod_layout_component *lod_comp;
+       int i, j, rc;
+       int picked = -1, second_pick = -1, third_pick = -1;
+       ENTRY;
+
+       if (OBD_FAIL_CHECK(OBD_FAIL_FLR_RANDOM_PICK_MIRROR)) {
+               get_random_bytes(&seq, sizeof(seq));
+               seq %= lo->ldo_mirror_count;
+       }
+
+       /**
+        * Pick a mirror as the primary, and check the availability of OSTs.
+        *
+        * This algo can be revised later after knowing the topology of
+        * cluster.
+        */
+       lod_qos_statfs_update(env, lod);
+       for (i = 0; i < lo->ldo_mirror_count; i++) {
+               bool ost_avail = true;
+               int index = (i + seq) % lo->ldo_mirror_count;
+
+               if (lo->ldo_mirrors[index].lme_stale) {
+                       CDEBUG(D_LAYOUT, DFID": mirror %d stale\n",
+                              PFID(lod_object_fid(lo)), index);
+                       continue;
+               }
+
+               /* 2nd pick is for the primary mirror containing unavail OST */
+               if (lo->ldo_mirrors[index].lme_primary && second_pick < 0)
+                       second_pick = index;
+
+               /* 3rd pick is for non-primary mirror containing unavail OST */
+               if (second_pick < 0 && third_pick < 0)
+                       third_pick = index;
+
+               /**
+                * we found a non-primary 1st pick, we'd like to find a
+                * potential pirmary mirror.
+                */
+               if (picked >= 0 && !lo->ldo_mirrors[index].lme_primary)
+                       continue;
+
+               /* check the availability of OSTs */
+               lod_foreach_mirror_comp(lod_comp, lo, index) {
+                       if (!lod_comp_inited(lod_comp) || !lod_comp->llc_stripe)
+                               continue;
+
+                       for (j = 0; j < lod_comp->llc_stripe_count; j++) {
+                               struct dt_object *dt = lod_comp->llc_stripe[j];
+
+                               rc = lod_check_ost_avail(env, lo, dt, index);
+                               if (rc < 0)
+                                       RETURN(rc);
+
+                               ost_avail = !!rc;
+                               if (!ost_avail)
+                                       break;
+                       } /* for all dt object in one component */
+                       if (!ost_avail)
+                               break;
+               } /* for all components in a mirror */
+
+               /**
+                * the OSTs where allocated objects locates in the components
+                * of the mirror are available.
+                */
+               if (!ost_avail)
+                       continue;
+
+               /* this mirror has all OSTs available */
+               picked = index;
+
+               /**
+                * primary with all OSTs are available, this is the perfect
+                * 1st pick.
+                */
+               if (lo->ldo_mirrors[index].lme_primary)
                        break;
+       } /* for all mirrors */
+
+       /* failed to pick a sound mirror, lower our expectation */
+       if (picked < 0)
+               picked = second_pick;
+       if (picked < 0)
+               picked = third_pick;
+       if (picked < 0)
+               RETURN(-ENODATA);
+
+       RETURN(picked);
+}
+
+static int lod_prepare_resync_mirror(const struct lu_env *env,
+                                    struct lod_object *lo,
+                                    __u16 mirror_id)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lod_layout_component *lod_comp;
+       int i;
+
+       for (i = 0; i < lo->ldo_mirror_count; i++) {
+               if (lo->ldo_mirrors[i].lme_id != mirror_id)
+                       continue;
+
+               lod_foreach_mirror_comp(lod_comp, lo, i) {
+                       if (lod_comp_inited(lod_comp))
+                               continue;
+
+                       info->lti_comp_idx[info->lti_count++] =
+                               lod_comp_index(lo, lod_comp);
+               }
        }
 
-       if (need_create)
-               lod_obj_inc_layout_gen(lo);
-       else
-               GOTO(unlock, rc = -EALREADY);
+       return 0;
+}
 
-       if (!rc) {
-               info->lti_buf.lb_len = lod_comp_md_size(lo, false);
-               rc = lod_sub_declare_xattr_set(env, next, &info->lti_buf,
-                                              XATTR_NAME_LOV, 0, th);
+/**
+ * figure out the components should be instantiated for resync.
+ */
+static int lod_prepare_resync(const struct lu_env *env, struct lod_object *lo,
+                             struct lu_extent *extent)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lod_layout_component *lod_comp;
+       unsigned int need_sync = 0;
+       int i;
+
+       CDEBUG(D_LAYOUT,
+              DFID": instantiate all stale components in "DEXT"\n",
+              PFID(lod_object_fid(lo)), PEXT(extent));
+
+       /**
+        * instantiate all components within this extent, even non-stale
+        * components.
+        */
+       for (i = 0; i < lo->ldo_mirror_count; i++) {
+               if (!lo->ldo_mirrors[i].lme_stale)
+                       continue;
+
+               lod_foreach_mirror_comp(lod_comp, lo, i) {
+                       if (!lu_extent_is_overlapped(extent,
+                                               &lod_comp->llc_extent))
+                               break;
+
+                       need_sync++;
+
+                       if (lod_comp_inited(lod_comp))
+                               continue;
+
+                       CDEBUG(D_LAYOUT, "resync instantiate %d / %d\n",
+                              i, lod_comp_index(lo, lod_comp));
+                       info->lti_comp_idx[info->lti_count++] =
+                                       lod_comp_index(lo, lod_comp);
+               }
+       }
+
+       return need_sync ? 0 : -EALREADY;
+}
+
+static int lod_declare_update_rdonly(const struct lu_env *env,
+               struct lod_object *lo, struct md_layout_change *mlc,
+               struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lu_attr *layout_attr = &info->lti_layout_attr;
+       struct lod_layout_component *lod_comp;
+       struct lu_extent extent = { 0 };
+       int rc;
+       ENTRY;
+
+       LASSERT(lo->ldo_flr_state == LCM_FL_RDONLY);
+       LASSERT(mlc->mlc_opc == MD_LAYOUT_WRITE ||
+               mlc->mlc_opc == MD_LAYOUT_RESYNC);
+       LASSERT(lo->ldo_mirror_count > 0);
+
+       if (mlc->mlc_opc == MD_LAYOUT_WRITE) {
+               struct layout_intent *layout = mlc->mlc_intent;
+               int picked;
+
+               extent = layout->li_extent;
+               CDEBUG(D_LAYOUT, DFID": trying to write :"DEXT"\n",
+                      PFID(lod_object_fid(lo)), PEXT(&extent));
+
+               picked = lod_primary_pick(env, lo, &extent);
+               if (picked < 0)
+                       RETURN(picked);
+
+               CDEBUG(D_LAYOUT, DFID": picked mirror id %u as primary\n",
+                      PFID(lod_object_fid(lo)),
+                      lo->ldo_mirrors[picked].lme_id);
+
+               if (layout->li_opc == LAYOUT_INTENT_TRUNC) {
+                       /**
+                        * trunc transfers [0, size) in the intent extent, we'd
+                        * stale components overlapping [size, eof).
+                        */
+                       extent.e_start = extent.e_end;
+                       extent.e_end = OBD_OBJECT_EOF;
+               }
+
+               /* stale overlapping components from other mirrors */
+               lod_stale_components(lo, picked, &extent);
+
+               /* restore truncate intent extent */
+               if (layout->li_opc == LAYOUT_INTENT_TRUNC)
+                       extent.e_end = extent.e_start;
+
+               /* instantiate components for the picked mirror, start from 0 */
+               extent.e_start = 0;
+
+               lod_foreach_mirror_comp(lod_comp, lo, picked) {
+                       if (!lu_extent_is_overlapped(&extent,
+                                                    &lod_comp->llc_extent))
+                               break;
+
+                       if (lod_comp_inited(lod_comp))
+                               continue;
+
+                       info->lti_comp_idx[info->lti_count++] =
+                                               lod_comp_index(lo, lod_comp);
+               }
+
+               lo->ldo_flr_state = LCM_FL_WRITE_PENDING;
+       } else { /* MD_LAYOUT_RESYNC */
+               int i;
+
+               /**
+                * could contain multiple non-stale mirrors, so we need to
+                * prep uninited all components assuming any non-stale mirror
+                * could be picked as the primary mirror.
+                */
+               if (mlc->mlc_mirror_id == 0) {
+                       /* normal resync */
+                       for (i = 0; i < lo->ldo_mirror_count; i++) {
+                               if (lo->ldo_mirrors[i].lme_stale)
+                                       continue;
+
+                               lod_foreach_mirror_comp(lod_comp, lo, i) {
+                                       if (!lod_comp_inited(lod_comp))
+                                               break;
+
+                                       if (extent.e_end <
+                                               lod_comp->llc_extent.e_end)
+                                               extent.e_end =
+                                                    lod_comp->llc_extent.e_end;
+                               }
+                       }
+                       rc = lod_prepare_resync(env, lo, &extent);
+                       if (rc)
+                               GOTO(out, rc);
+               } else {
+                       /* mirror write, try to init its all components */
+                       rc = lod_prepare_resync_mirror(env, lo,
+                                                      mlc->mlc_mirror_id);
+                       if (rc)
+                               GOTO(out, rc);
+               }
+
+               /* change the file state to SYNC_PENDING */
+               lo->ldo_flr_state = LCM_FL_SYNC_PENDING;
+       }
+
+       /* Reset the layout version once it's becoming too large.
+        * This way it can make sure that the layout version is
+        * monotonously increased in this writing era. */
+       lod_obj_inc_layout_gen(lo);
+       if (lo->ldo_layout_gen > (LCME_ID_MAX >> 1)) {
+               __u32 layout_version;
+
+               cfs_get_random_bytes(&layout_version, sizeof(layout_version));
+               lo->ldo_layout_gen = layout_version & 0xffff;
        }
+
+       rc = lod_declare_instantiate_components(env, lo, th);
+       if (rc)
+               GOTO(out, rc);
+
+       layout_attr->la_valid = LA_LAYOUT_VERSION;
+       layout_attr->la_layout_version = 0; /* set current version */
+       if (mlc->mlc_opc == MD_LAYOUT_RESYNC)
+               layout_attr->la_layout_version = LU_LAYOUT_RESYNC;
+       rc = lod_declare_attr_set(env, &lo->ldo_obj, layout_attr, th);
+       if (rc)
+               GOTO(out, rc);
+
 out:
        if (rc)
-               lod_object_free_striping(env, lo);
+               lod_striping_free(env, lo);
+       RETURN(rc);
+}
 
-unlock:
-       dt_write_unlock(env, next);
+static int lod_declare_update_write_pending(const struct lu_env *env,
+               struct lod_object *lo, struct md_layout_change *mlc,
+               struct thandle *th)
+{
+       struct lod_thread_info *info = lod_env_info(env);
+       struct lu_attr *layout_attr = &info->lti_layout_attr;
+       struct lod_layout_component *lod_comp;
+       struct lu_extent extent = { 0 };
+       int primary = -1;
+       int i;
+       int rc;
+       ENTRY;
+
+       LASSERT(lo->ldo_flr_state == LCM_FL_WRITE_PENDING);
+       LASSERT(mlc->mlc_opc == MD_LAYOUT_WRITE ||
+               mlc->mlc_opc == MD_LAYOUT_RESYNC);
+
+       /* look for the primary mirror */
+       for (i = 0; i < lo->ldo_mirror_count; i++) {
+               if (lo->ldo_mirrors[i].lme_stale)
+                       continue;
+
+               LASSERTF(primary < 0, DFID " has multiple primary: %u / %u",
+                        PFID(lod_object_fid(lo)),
+                        lo->ldo_mirrors[i].lme_id,
+                        lo->ldo_mirrors[primary].lme_id);
+
+               primary = i;
+       }
+       if (primary < 0) {
+               CERROR(DFID ": doesn't have a primary mirror\n",
+                      PFID(lod_object_fid(lo)));
+               GOTO(out, rc = -ENODATA);
+       }
+
+       CDEBUG(D_LAYOUT, DFID": found primary %u\n",
+              PFID(lod_object_fid(lo)), lo->ldo_mirrors[primary].lme_id);
+
+       LASSERT(!lo->ldo_mirrors[primary].lme_stale);
+
+       /* for LAYOUT_WRITE opc, it has to do the following operations:
+        * 1. stale overlapping componets from stale mirrors;
+        * 2. instantiate components of the primary mirror;
+        * 3. transfter layout version to all objects of the primary;
+        *
+        * for LAYOUT_RESYNC opc, it will do:
+        * 1. instantiate components of all stale mirrors;
+        * 2. transfer layout version to all objects to close write era. */
+
+       if (mlc->mlc_opc == MD_LAYOUT_WRITE) {
+               LASSERT(mlc->mlc_intent != NULL);
+
+               extent = mlc->mlc_intent->li_extent;
+
+               CDEBUG(D_LAYOUT, DFID": intent to write: "DEXT"\n",
+                      PFID(lod_object_fid(lo)), PEXT(&extent));
+
+               if (mlc->mlc_intent->li_opc == LAYOUT_INTENT_TRUNC) {
+                       /**
+                        * trunc transfers [0, size) in the intent extent, we'd
+                        * stale components overlapping [size, eof).
+                        */
+                       extent.e_start = extent.e_end;
+                       extent.e_end = OBD_OBJECT_EOF;
+               }
+               /* 1. stale overlapping components */
+               lod_stale_components(lo, primary, &extent);
+
+               /* 2. find out the components need instantiating.
+                * instantiate [0, mlc->mlc_intent->e_end) */
+
+               /* restore truncate intent extent */
+               if (mlc->mlc_intent->li_opc == LAYOUT_INTENT_TRUNC)
+                       extent.e_end = extent.e_start;
+               extent.e_start = 0;
+
+               lod_foreach_mirror_comp(lod_comp, lo, primary) {
+                       if (!lu_extent_is_overlapped(&extent,
+                                                    &lod_comp->llc_extent))
+                               break;
+
+                       if (lod_comp_inited(lod_comp))
+                               continue;
+
+                       CDEBUG(D_LAYOUT, "write instantiate %d / %d\n",
+                              primary, lod_comp_index(lo, lod_comp));
+                       info->lti_comp_idx[info->lti_count++] =
+                                               lod_comp_index(lo, lod_comp);
+               }
+       } else { /* MD_LAYOUT_RESYNC */
+               if (mlc->mlc_mirror_id == 0) {
+                       /* normal resync */
+                       lod_foreach_mirror_comp(lod_comp, lo, primary) {
+                               if (!lod_comp_inited(lod_comp))
+                                       break;
+
+                               extent.e_end = lod_comp->llc_extent.e_end;
+                       }
+
+                       rc = lod_prepare_resync(env, lo, &extent);
+                       if (rc)
+                               GOTO(out, rc);
+               } else {
+                       /* mirror write, try to init its all components */
+                       rc = lod_prepare_resync_mirror(env, lo,
+                                                      mlc->mlc_mirror_id);
+                       if (rc)
+                               GOTO(out, rc);
+               }
+
+               /* change the file state to SYNC_PENDING */
+               lo->ldo_flr_state = LCM_FL_SYNC_PENDING;
+       }
+
+       rc = lod_declare_instantiate_components(env, lo, th);
+       if (rc)
+               GOTO(out, rc);
+
+       /* 3. transfer layout version to OST objects.
+        * transfer new layout version to OST objects so that stale writes
+        * can be denied. It also ends an era of writing by setting
+        * LU_LAYOUT_RESYNC. Normal client can never use this bit to
+        * send write RPC; only resync RPCs could do it. */
+       layout_attr->la_valid = LA_LAYOUT_VERSION;
+       layout_attr->la_layout_version = 0; /* set current version */
+       if (mlc->mlc_opc == MD_LAYOUT_RESYNC)
+               layout_attr->la_layout_version = LU_LAYOUT_RESYNC;
+       rc = lod_declare_attr_set(env, &lo->ldo_obj, layout_attr, th);
+       if (rc)
+               GOTO(out, rc);
+
+       lod_obj_inc_layout_gen(lo);
+out:
+       if (rc)
+               lod_striping_free(env, lo);
+       RETURN(rc);
+}
+
+static int lod_declare_update_sync_pending(const struct lu_env *env,
+               struct lod_object *lo, struct md_layout_change *mlc,
+               struct thandle *th)
+{
+       struct lod_thread_info  *info = lod_env_info(env);
+       unsigned sync_components = 0;
+       unsigned resync_components = 0;
+       int i;
+       int rc;
+       ENTRY;
+
+       LASSERT(lo->ldo_flr_state == LCM_FL_SYNC_PENDING);
+       LASSERT(mlc->mlc_opc == MD_LAYOUT_RESYNC_DONE ||
+               mlc->mlc_opc == MD_LAYOUT_WRITE);
+
+       CDEBUG(D_LAYOUT, DFID ": received op %d in sync pending\n",
+              PFID(lod_object_fid(lo)), mlc->mlc_opc);
+
+       if (mlc->mlc_opc == MD_LAYOUT_WRITE) {
+               CDEBUG(D_LAYOUT, DFID": cocurrent write to sync pending\n",
+                      PFID(lod_object_fid(lo)));
+
+               lo->ldo_flr_state = LCM_FL_WRITE_PENDING;
+               return lod_declare_update_write_pending(env, lo, mlc, th);
+       }
+
+       /* MD_LAYOUT_RESYNC_DONE */
+
+       for (i = 0; i < lo->ldo_comp_cnt; i++) {
+               struct lod_layout_component *lod_comp;
+               int j;
+
+               lod_comp = &lo->ldo_comp_entries[i];
+
+               if (!(lod_comp->llc_flags & LCME_FL_STALE)) {
+                       sync_components++;
+                       continue;
+               }
+
+               for (j = 0; j < mlc->mlc_resync_count; j++) {
+                       if (lod_comp->llc_id != mlc->mlc_resync_ids[j])
+                               continue;
+
+                       mlc->mlc_resync_ids[j] = LCME_ID_INVAL;
+                       lod_comp->llc_flags &= ~LCME_FL_STALE;
+                       resync_components++;
+                       break;
+               }
+       }
+
+       /* valid check */
+       for (i = 0; i < mlc->mlc_resync_count; i++) {
+               if (mlc->mlc_resync_ids[i] == LCME_ID_INVAL)
+                       continue;
+
+               CDEBUG(D_LAYOUT, DFID": lcme id %u (%d / %zd) not exist "
+                      "or already synced\n", PFID(lod_object_fid(lo)),
+                      mlc->mlc_resync_ids[i], i, mlc->mlc_resync_count);
+               GOTO(out, rc = -EINVAL);
+       }
+
+       if (!sync_components || (mlc->mlc_resync_count && !resync_components)) {
+               CDEBUG(D_LAYOUT, DFID": no mirror in sync\n",
+                      PFID(lod_object_fid(lo)));
+
+               /* tend to return an error code here to prevent
+                * the MDT from setting SoM attribute */
+               GOTO(out, rc = -EINVAL);
+       }
+
+       CDEBUG(D_LAYOUT, DFID": resynced %u/%zu components\n",
+              PFID(lod_object_fid(lo)),
+              resync_components, mlc->mlc_resync_count);
+
+       lo->ldo_flr_state = LCM_FL_RDONLY;
+       lod_obj_inc_layout_gen(lo);
+
+       info->lti_buf.lb_len = lod_comp_md_size(lo, false);
+       rc = lod_sub_declare_xattr_set(env, lod_object_child(lo),
+                                      &info->lti_buf, XATTR_NAME_LOV, 0, th);
+       EXIT;
+
+out:
+       if (rc)
+               lod_striping_free(env, lo);
+       RETURN(rc);
+}
+
+static int lod_declare_layout_change(const struct lu_env *env,
+               struct dt_object *dt, struct md_layout_change *mlc,
+               struct thandle *th)
+{
+       struct lod_thread_info  *info = lod_env_info(env);
+       struct lod_object *lo = lod_dt_obj(dt);
+       int rc;
+       ENTRY;
+
+       if (!S_ISREG(dt->do_lu.lo_header->loh_attr) || !dt_object_exists(dt) ||
+           dt_object_remote(dt_object_child(dt)))
+               RETURN(-EINVAL);
+
+       rc = lod_striping_load(env, lo);
+       if (rc)
+               GOTO(out, rc);
+
+       LASSERT(lo->ldo_comp_cnt > 0);
+
+       rc = lod_layout_data_init(info, lo->ldo_comp_cnt);
+       if (rc)
+               GOTO(out, rc);
 
+       switch (lo->ldo_flr_state) {
+       case LCM_FL_NONE:
+               rc = lod_declare_update_plain(env, lo, mlc->mlc_intent,
+                                             &mlc->mlc_buf, th);
+               break;
+       case LCM_FL_RDONLY:
+               rc = lod_declare_update_rdonly(env, lo, mlc, th);
+               break;
+       case LCM_FL_WRITE_PENDING:
+               rc = lod_declare_update_write_pending(env, lo, mlc, th);
+               break;
+       case LCM_FL_SYNC_PENDING:
+               rc = lod_declare_update_sync_pending(env, lo, mlc, th);
+               break;
+       default:
+               rc = -ENOTSUPP;
+               break;
+       }
+out:
        RETURN(rc);
 }
 
@@ -4972,12 +6609,20 @@ unlock:
  * Instantiate layout component objects which covers the intent write offset.
  */
 static int lod_layout_change(const struct lu_env *env, struct dt_object *dt,
-                            struct layout_intent *layout,
-                            const struct lu_buf *buf, struct thandle *th)
+                            struct md_layout_change *mlc, struct thandle *th)
 {
        struct lu_attr *attr = &lod_env_info(env)->lti_attr;
+       struct lu_attr *layout_attr = &lod_env_info(env)->lti_layout_attr;
+       struct lod_object *lo = lod_dt_obj(dt);
+       int rc;
 
-       RETURN(lod_striped_create(env, dt, attr, NULL, th));
+       rc = lod_striped_create(env, dt, attr, NULL, th);
+       if (!rc && layout_attr->la_valid & LA_LAYOUT_VERSION) {
+               layout_attr->la_layout_version |= lo->ldo_layout_gen;
+               rc = lod_attr_set(env, dt, layout_attr, th);
+       }
+
+       return rc;
 }
 
 struct dt_object_operations lod_obj_ops = {
@@ -5049,11 +6694,11 @@ static ssize_t lod_declare_write(const struct lu_env *env,
  */
 static ssize_t lod_write(const struct lu_env *env, struct dt_object *dt,
                         const struct lu_buf *buf, loff_t *pos,
-                        struct thandle *th, int iq)
+                        struct thandle *th)
 {
        LASSERT(S_ISREG(dt->do_lu.lo_header->loh_attr) ||
                S_ISLNK(dt->do_lu.lo_header->loh_attr));
-       return lod_sub_write(env, dt_object_child(dt), buf, pos, th, iq);
+       return lod_sub_write(env, dt_object_child(dt), buf, pos, th);
 }
 
 static int lod_declare_punch(const struct lu_env *env, struct dt_object *dt,
@@ -5175,7 +6820,7 @@ static int lod_object_init(const struct lu_env *env, struct lu_object *lo,
  * \param[in] env      execution environment
  * \param[in] lo       object
  */
-void lod_object_free_striping(const struct lu_env *env, struct lod_object *lo)
+void lod_striping_free_nolock(const struct lu_env *env, struct lod_object *lo)
 {
        struct lod_layout_component *lod_comp;
        int i, j;
@@ -5193,6 +6838,7 @@ void lod_object_free_striping(const struct lu_env *env, struct lod_object *lo)
                OBD_FREE(lo->ldo_stripe, j);
                lo->ldo_stripe = NULL;
                lo->ldo_dir_stripes_allocated = 0;
+               lo->ldo_dir_stripe_loaded = 0;
                lo->ldo_dir_stripe_count = 0;
        } else if (lo->ldo_comp_entries != NULL) {
                for (i = 0; i < lo->ldo_comp_cnt; i++) {
@@ -5211,6 +6857,10 @@ void lod_object_free_striping(const struct lu_env *env, struct lod_object *lo)
                                 sizeof(struct dt_object *) *
                                 lod_comp->llc_stripes_allocated);
                        lod_comp->llc_stripe = NULL;
+                       OBD_FREE(lod_comp->llc_ost_indices,
+                                sizeof(__u32) *
+                                lod_comp->llc_stripes_allocated);
+                       lod_comp->llc_ost_indices = NULL;
                        lod_comp->llc_stripes_allocated = 0;
                }
                lod_free_comp_entries(lo);
@@ -5218,6 +6868,13 @@ void lod_object_free_striping(const struct lu_env *env, struct lod_object *lo)
        }
 }
 
+void lod_striping_free(const struct lu_env *env, struct lod_object *lo)
+{
+       mutex_lock(&lo->ldo_layout_mutex);
+       lod_striping_free_nolock(env, lo);
+       mutex_unlock(&lo->ldo_layout_mutex);
+}
+
 /**
  * Implementation of lu_object_operations::loo_object_free.
  *
@@ -5229,7 +6886,7 @@ static void lod_object_free(const struct lu_env *env, struct lu_object *o)
        struct lod_object *lo = lu2lod_obj(o);
 
        /* release all underlying object pinned */
-       lod_object_free_striping(env, lo);
+       lod_striping_free(env, lo);
        lu_object_fini(o);
        OBD_SLAB_FREE_PTR(lo, lod_object_kmem);
 }