X-Git-Url: https://git.whamcloud.com/?a=blobdiff_plain;f=lustre%2Fosd-zfs%2Fosd_oi.c;h=e350ba82b515bd133b307523ffd266f203b299d7;hb=5277d9452ae990d53ca84a8cfb2150bda06772fb;hp=371c442e5468efa878622bb7eb4f0eaea2d87976;hpb=745c19c70319915a55b71b81b4e89d68e3a4e272;p=fs%2Flustre-release.git

diff --git a/lustre/osd-zfs/osd_oi.c b/lustre/osd-zfs/osd_oi.c
index 371c442..e350ba8 100644
--- a/lustre/osd-zfs/osd_oi.c
+++ b/lustre/osd-zfs/osd_oi.c
@@ -15,21 +15,15 @@
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
 /*
  * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
- */
-/*
- * Copyright (c) 2012, 2013, Intel Corporation.
- * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, 2016, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -45,7 +39,6 @@
 
 #define DEBUG_SUBSYSTEM S_OSD
 
-#include <lustre_ver.h>
 #include <libcfs/libcfs.h>
 #include <obd_support.h>
 #include <lustre_net.h>
@@ -85,18 +78,17 @@ struct named_oid {
 };
 
 static const struct named_oid oids[] = {
-	{ LAST_RECV_OID,		LAST_RCVD },
-	{ OFD_LAST_GROUP_OID,		"LAST_GROUP" },
-	{ LLOG_CATALOGS_OID,		"CATALOGS" },
-	{ MGS_CONFIGS_OID,              NULL /*MOUNT_CONFIGS_DIR*/ },
-	{ FID_SEQ_SRV_OID,              "seq_srv" },
-	{ FID_SEQ_CTL_OID,              "seq_ctl" },
-	{ FLD_INDEX_OID,                "fld" },
-	{ MDD_LOV_OBJ_OID,		LOV_OBJID },
-	{ OFD_HEALTH_CHECK_OID,		HEALTH_CHECK },
-	{ ACCT_USER_OID,		"acct_usr_inode" },
-	{ ACCT_GROUP_OID,		"acct_grp_inode" },
-	{ 0,				NULL }
+	{ .oid = LAST_RECV_OID,	       .name = LAST_RCVD },
+	{ .oid = OFD_LAST_GROUP_OID,   .name = "LAST_GROUP" },
+	{ .oid = LLOG_CATALOGS_OID,    .name = "CATALOGS" },
+	{ .oid = MGS_CONFIGS_OID,      /*MOUNT_CONFIGS_DIR*/ },
+	{ .oid = FID_SEQ_SRV_OID,      .name = "seq_srv" },
+	{ .oid = FID_SEQ_CTL_OID,      .name = "seq_ctl" },
+	{ .oid = FLD_INDEX_OID,	       .name = "fld" },
+	{ .oid = MDD_LOV_OBJ_OID,      .name = LOV_OBJID },
+	{ .oid = OFD_HEALTH_CHECK_OID, .name = HEALTH_CHECK },
+	{ .oid = REPLY_DATA_OID,       .name = REPLY_DATA },
+	{ .oid = 0 }
 };
 
 static char *oid2name(const unsigned long oid)
@@ -129,10 +121,9 @@ osd_oi_lookup(const struct lu_env *env, struct osd_device *o,
 	if (rc >= sizeof(oi->oi_name))
 		return -E2BIG;
 
-	rc = 0;
 	oi->oi_zapid = zde->zde_dnode;
 
-	return rc;
+	return 0;
 }
 
 /**
@@ -144,8 +135,9 @@ osd_oi_create(const struct lu_env *env, struct osd_device *o,
 {
 	struct zpl_direntry	*zde = &osd_oti_get(env)->oti_zde.lzd_reg;
 	struct lu_attr		*la = &osd_oti_get(env)->oti_la;
-	dmu_buf_t		*db;
+	sa_handle_t		*sa_hdl = NULL;
 	dmu_tx_t		*tx;
+	uint64_t		 oid;
 	int			 rc;
 
 	/* verify it doesn't already exist */
@@ -153,6 +145,9 @@ osd_oi_create(const struct lu_env *env, struct osd_device *o,
 	if (rc == 0)
 		return -EEXIST;
 
+	if (o->od_dt_dev.dd_rdonly)
+		return -EROFS;
+
 	/* create fid-to-dnode index */
 	tx = dmu_tx_create(o->od_os);
 	if (tx == NULL)
@@ -161,7 +156,6 @@ osd_oi_create(const struct lu_env *env, struct osd_device *o,
 	dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, 1, NULL);
 	dmu_tx_hold_bonus(tx, parent);
 	dmu_tx_hold_zap(tx, parent, TRUE, name);
-	LASSERT(tx->tx_objset->os_sa);
 	dmu_tx_hold_sa_create(tx, ZFS_SA_BASE_ATTR_SIZE);
 
 	rc = -dmu_tx_assign(tx, TXG_WAIT);
@@ -170,21 +164,36 @@ osd_oi_create(const struct lu_env *env, struct osd_device *o,
 		return rc;
 	}
 
+	oid = osd_zap_create_flags(o->od_os, 0, ZAP_FLAG_HASH64,
+				   DMU_OT_DIRECTORY_CONTENTS,
+				   14, /* == ZFS fzap_default_block_shift */
+				   DN_MAX_INDBLKSHIFT,
+				   0, tx);
+
+	rc = -sa_handle_get(o->od_os, oid, NULL, SA_HDL_PRIVATE, &sa_hdl);
+	if (rc)
+		goto commit;
 	la->la_valid = LA_MODE | LA_UID | LA_GID;
 	la->la_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
 	la->la_uid = la->la_gid = 0;
-	__osd_zap_create(env, o, &db, tx, la, parent, 0);
+	rc = __osd_attr_init(env, o, sa_hdl, tx, la, parent, NULL);
+	sa_handle_destroy(sa_hdl);
+	if (rc)
+		goto commit;
 
-	zde->zde_dnode = db->db_object;
+	zde->zde_dnode = oid;
 	zde->zde_pad = 0;
 	zde->zde_type = IFTODT(S_IFDIR);
 
 	rc = -zap_add(o->od_os, parent, name, 8, 1, (void *)zde, tx);
 
+commit:
+	if (rc)
+		dmu_object_free(o->od_os, oid, tx);
 	dmu_tx_commit(tx);
 
-	*child = db->db_object;
-	sa_buf_rele(db, osd_obj_tag);
+	if (rc == 0)
+		*child = oid;
 
 	return rc;
 }
@@ -210,7 +219,7 @@ osd_oi_find_or_create(const struct lu_env *env, struct osd_device *o,
  * the object is located (tgt index) and it is MDT or OST object.
  */
 int osd_fld_lookup(const struct lu_env *env, struct osd_device *osd,
-		   obd_seq seq, struct lu_seq_range *range)
+		   u64 seq, struct lu_seq_range *range)
 {
 	struct seq_server_site	*ss = osd_seq_site(osd);
 
@@ -251,6 +260,14 @@ int fid_is_on_ost(const struct lu_env *env, struct osd_device *osd,
 
 	rc = osd_fld_lookup(env, osd, fid_seq(fid), range);
 	if (rc != 0) {
+		/* During upgrade, OST FLDB might not be loaded because
+		 * OST FLDB is not created until 2.6, so if some DNE
+		 * filesystem upgrade from 2.5 to 2.7/2.8, they will
+		 * not be able to find the sequence from local FLDB
+		 * cache see fld_index_init(). */
+		if (rc == -ENOENT && osd->od_is_ost)
+			RETURN(1);
+
 		if (rc != -ENOENT)
 			CERROR("%s: "DFID" lookup failed: rc = %d\n",
 			       osd_name(osd), PFID(fid), rc);
@@ -264,7 +281,7 @@ int fid_is_on_ost(const struct lu_env *env, struct osd_device *osd,
 }
 
 static struct osd_seq *osd_seq_find_locked(struct osd_seq_list *seq_list,
-					   obd_seq seq)
+					   u64 seq)
 {
 	struct osd_seq *osd_seq;
 
@@ -275,8 +292,7 @@ static struct osd_seq *osd_seq_find_locked(struct osd_seq_list *seq_list,
 	return NULL;
 }
 
-static struct osd_seq *osd_seq_find(struct osd_seq_list *seq_list,
-				    obd_seq seq)
+static struct osd_seq *osd_seq_find(struct osd_seq_list *seq_list, u64 seq)
 {
 	struct osd_seq *osd_seq;
 
@@ -288,7 +304,7 @@ static struct osd_seq *osd_seq_find(struct osd_seq_list *seq_list,
 }
 
 static struct osd_seq *osd_find_or_add_seq(const struct lu_env *env,
-					   struct osd_device *osd, obd_seq seq)
+					   struct osd_device *osd, u64 seq)
 {
 	struct osd_seq_list	*seq_list = &osd->od_seq_list;
 	struct osd_seq		*osd_seq;
@@ -328,7 +344,7 @@ static struct osd_seq *osd_find_or_add_seq(const struct lu_env *env,
 
 	oi.oi_zapid = osd->od_O_id;
 	sprintf(seq_name, (fid_seq_is_rsvd(seq) ||
-		fid_seq_is_mdt0(seq)) ?  LPU64 : LPX64i,
+		fid_seq_is_mdt0(seq)) ?  "%llu" : "%llx",
 		fid_seq_is_idif(seq) ? 0 : seq);
 
 	rc = osd_oi_find_or_create(env, osd, oi.oi_zapid, seq_name, &odb);
@@ -369,11 +385,11 @@ out:
  */
 static uint64_t
 osd_get_idx_for_ost_obj(const struct lu_env *env, struct osd_device *osd,
-			const struct lu_fid *fid, char *buf)
+			const struct lu_fid *fid, char *buf, int bufsize)
 {
 	struct osd_seq	*osd_seq;
 	unsigned long	b;
-	obd_id		id;
+	u64		id;
 	int		rc;
 
 	osd_seq = osd_find_or_add_seq(env, osd, fid_seq(fid));
@@ -394,7 +410,8 @@ osd_get_idx_for_ost_obj(const struct lu_env *env, struct osd_device *osd,
 	b = id % OSD_OST_MAP_SIZE;
 	LASSERT(osd_seq->os_compat_dirs[b]);
 
-	sprintf(buf, LPU64, id);
+	if (buf)
+		snprintf(buf, bufsize, "%llu", id);
 
 	return osd_seq->os_compat_dirs[b];
 }
@@ -413,41 +430,47 @@ static void osd_fid2str(char *buf, const struct lu_fid *fid)
  */
 static uint64_t
 osd_get_idx_for_fid(struct osd_device *osd, const struct lu_fid *fid,
-		    char *buf)
+		    char *buf, dnode_t **zdn)
 {
 	struct osd_oi *oi;
 
 	LASSERT(osd->od_oi_table != NULL);
 	oi = osd->od_oi_table[fid_seq(fid) & (osd->od_oi_count - 1)];
-	osd_fid2str(buf, fid);
+	if (buf)
+		osd_fid2str(buf, fid);
+	if (zdn)
+		*zdn = oi->oi_dn;
 
 	return oi->oi_zapid;
 }
 
 uint64_t osd_get_name_n_idx(const struct lu_env *env, struct osd_device *osd,
-			    const struct lu_fid *fid, char *buf)
+			    const struct lu_fid *fid, char *buf, int bufsize,
+			    dnode_t **zdn)
 {
 	uint64_t zapid;
 
 	LASSERT(fid);
-	LASSERT(buf);
+	LASSERT(!fid_is_acct(fid));
+
+	if (zdn != NULL)
+		*zdn = NULL;
 
 	if (fid_is_on_ost(env, osd, fid) == 1 || fid_seq(fid) == FID_SEQ_ECHO) {
-		zapid = osd_get_idx_for_ost_obj(env, osd, fid, buf);
+		zapid = osd_get_idx_for_ost_obj(env, osd, fid, buf, bufsize);
 	} else if (unlikely(fid_seq(fid) == FID_SEQ_LOCAL_FILE)) {
 		/* special objects with fixed known fids get their name */
 		char *name = oid2name(fid_oid(fid));
 
 		if (name) {
 			zapid = osd->od_root;
-			strcpy(buf, name);
-			if (fid_is_acct(fid))
-				zapid = MASTER_NODE_OBJ;
+			if (buf)
+				strncpy(buf, name, bufsize);
 		} else {
-			zapid = osd_get_idx_for_fid(osd, fid, buf);
+			zapid = osd_get_idx_for_fid(osd, fid, buf, NULL);
 		}
 	} else {
-		zapid = osd_get_idx_for_fid(osd, fid, buf);
+		zapid = osd_get_idx_for_fid(osd, fid, buf, zdn);
 	}
 
 	return zapid;
@@ -465,32 +488,31 @@ int osd_fid_lookup(const struct lu_env *env, struct osd_device *dev,
 {
 	struct osd_thread_info	*info = osd_oti_get(env);
 	char			*buf = info->oti_buf;
-	uint64_t		zapid;
+	dnode_t *zdn;
+	uint64_t zapid;
 	int			rc = 0;
 	ENTRY;
 
-	if (OBD_FAIL_CHECK(OBD_FAIL_OST_ENOENT))
+	if (OBD_FAIL_CHECK(OBD_FAIL_SRV_ENOENT))
 		RETURN(-ENOENT);
 
-	if (unlikely(fid_is_acct(fid))) {
-		if (fid_oid(fid) == ACCT_USER_OID)
-			*oid = dev->od_iusr_oid;
-		else
-			*oid = dev->od_igrp_oid;
-	} else if (unlikely(fid_is_fs_root(fid))) {
+	LASSERT(!fid_is_acct(fid));
+
+	if (unlikely(fid_is_fs_root(fid))) {
 		*oid = dev->od_root;
 	} else {
-		zapid = osd_get_name_n_idx(env, dev, fid, buf);
-
-		rc = -zap_lookup(dev->od_os, zapid, buf,
-				8, 1, &info->oti_zde);
+		zapid = osd_get_name_n_idx(env, dev, fid, buf,
+					   sizeof(info->oti_buf), &zdn);
+		rc = osd_zap_lookup(dev, zapid, zdn, buf,
+				    8, 1, &info->oti_zde);
 		if (rc)
 			RETURN(rc);
 		*oid = info->oti_zde.lzd_reg.zde_dnode;
 	}
 
 	if (rc == 0)
-		dmu_prefetch(dev->od_os, *oid, 0, 0);
+		osd_dmu_prefetch(dev->od_os, *oid, 0, 0, 0,
+				 ZIO_PRIORITY_ASYNC_READ);
 
 	RETURN(rc);
 }
@@ -507,6 +529,8 @@ osd_oi_remove_table(const struct lu_env *env, struct osd_device *o, int key)
 
 	oi = o->od_oi_table[key];
 	if (oi) {
+		if (oi->oi_dn)
+			osd_dnode_rele(oi->oi_dn);
 		OBD_FREE_PTR(oi);
 		o->od_oi_table[key] = NULL;
 	}
@@ -536,6 +560,7 @@ osd_oi_add_table(const struct lu_env *env, struct osd_device *o,
 	}
 
 	o->od_oi_table[key] = oi;
+	__osd_obj2dnode(o->od_os, oi->oi_zapid, &oi->oi_dn);
 
 	return 0;
 }
@@ -619,15 +644,6 @@ osd_oi_probe(const struct lu_env *env, struct osd_device *o, int *count)
 	RETURN(0);
 }
 
-static void osd_ost_seq_init(const struct lu_env *env, struct osd_device *osd)
-{
-	struct osd_seq_list *osl = &osd->od_seq_list;
-
-	INIT_LIST_HEAD(&osl->osl_seq_list);
-	rwlock_init(&osl->osl_seq_list_lock);
-	sema_init(&osl->osl_seq_init_sem, 1);
-}
-
 static void osd_ost_seq_fini(const struct lu_env *env, struct osd_device *osd)
 {
 	struct osd_seq_list	*osl = &osd->od_seq_list;
@@ -652,134 +668,14 @@ static void osd_ost_seq_fini(const struct lu_env *env, struct osd_device *osd)
 static int
 osd_oi_init_compat(const struct lu_env *env, struct osd_device *o)
 {
-	uint64_t	 odb, sdb;
-	int		 rc;
+	uint64_t sdb;
+	int rc;
 	ENTRY;
 
 	rc = osd_oi_find_or_create(env, o, o->od_root, "O", &sdb);
-	if (rc)
-		RETURN(rc);
-
-	o->od_O_id = sdb;
-
-	osd_ost_seq_init(env, o);
-	/* Create on-disk indexes to maintain per-UID/GID inode usage.
-	 * Those new indexes are created in the top-level ZAP outside the
-	 * namespace in order not to confuse ZPL which might interpret those
-	 * indexes as directories and assume the values are object IDs */
-	rc = osd_oi_find_or_create(env, o, MASTER_NODE_OBJ,
-			oid2name(ACCT_USER_OID), &odb);
-	if (rc)
-		RETURN(rc);
-	o->od_iusr_oid = odb;
-
-	rc = osd_oi_find_or_create(env, o, MASTER_NODE_OBJ,
-			oid2name(ACCT_GROUP_OID), &odb);
-	if (rc)
-		RETURN(rc);
-	o->od_igrp_oid = odb;
-
-	RETURN(rc);
-}
-
-static char *root2convert = "ROOT";
-/*
- * due to DNE requirements we have to change sequence of /ROOT object
- * so that it doesn't belong to the local sequence FID_SEQ_LOCAL_FILE
- * but a normal sequence living on MDS#0
- * this is the sole purpose of this function.
- *
- * This is only needed for pre-production 2.4 ZFS filesystems, and
- * can be removed in the future.
- */
-int osd_convert_root_to_new_seq(const struct lu_env *env,
-					struct osd_device *o)
-{
-	struct luz_direntry *lze = &osd_oti_get(env)->oti_zde;
-	char		    *buf = osd_oti_get(env)->oti_str;
-	struct lu_fid	     newfid;
-	uint64_t	     zapid;
-	dmu_tx_t	    *tx = NULL;
-	int		     rc;
-	ENTRY;
-
-	/* ignore OSTs */
-	if (strstr(o->od_svname, "MDT") == NULL)
-		RETURN(0);
-
-	/* lookup /ROOT */
-	rc = -zap_lookup(o->od_os, o->od_root, root2convert, 8,
-			 sizeof(*lze) / 8, (void *)lze);
-	/* doesn't exist or let actual user to handle the error */
-	if (rc)
-		RETURN(0);
-
-	CDEBUG(D_OTHER, "%s: /ROOT -> "DFID" -> "LPU64"\n", o->od_svname,
-	       PFID(&lze->lzd_fid), (long long int) lze->lzd_reg.zde_dnode);
-
-	/* already right one? */
-	if (fid_seq(&lze->lzd_fid) == FID_SEQ_ROOT)
-		return 0;
-
-	tx = dmu_tx_create(o->od_os);
-	if (tx == NULL)
-		return -ENOMEM;
-
-	dmu_tx_hold_bonus(tx, o->od_root);
-
-	/* declare delete/insert of the name */
-	dmu_tx_hold_zap(tx, o->od_root, TRUE, root2convert);
-	dmu_tx_hold_zap(tx, o->od_root, FALSE, root2convert);
-
-	/* declare that we'll remove object from fid-dnode mapping */
-	zapid = osd_get_name_n_idx(env, o, &lze->lzd_fid, buf);
-	dmu_tx_hold_bonus(tx, zapid);
-	dmu_tx_hold_zap(tx, zapid, FALSE, buf);
-
-	/* declare that we'll add object to fid-dnode mapping */
-	newfid.f_seq = FID_SEQ_ROOT;
-	newfid.f_oid = 1;
-	newfid.f_ver = 0;
-	zapid = osd_get_name_n_idx(env, o, &newfid, buf);
-	dmu_tx_hold_bonus(tx, zapid);
-	dmu_tx_hold_zap(tx, zapid, TRUE, buf);
-
-	rc = -dmu_tx_assign(tx, TXG_WAIT);
-	if (rc)
-		GOTO(err, rc);
-
-	rc = -zap_remove(o->od_os, o->od_root, root2convert, tx);
-	if (rc)
-		GOTO(err, rc);
-
-	/* remove from OI */
-	zapid = osd_get_name_n_idx(env, o, &lze->lzd_fid, buf);
-	rc = -zap_remove(o->od_os, zapid, buf, tx);
-	if (rc)
-		GOTO(err, rc);
-
-	lze->lzd_fid = newfid;
-	rc = -zap_add(o->od_os, o->od_root, root2convert,
-		      8, sizeof(*lze) / 8, (void *)lze, tx);
-	if (rc)
-		GOTO(err, rc);
-
-	/* add to OI with the new fid */
-	zapid = osd_get_name_n_idx(env, o, &newfid, buf);
-	rc = -zap_add(o->od_os, zapid, buf, 8, 1, &lze->lzd_reg, tx);
-	if (rc)
-		GOTO(err, rc);
-
+	if (!rc)
+		o->od_O_id = sdb;
 
-	/* LMA will be updated in mdd_compat_fixes */
-	dmu_tx_commit(tx);
-
-	RETURN(rc);
-
-err:
-	if (tx)
-		dmu_tx_abort(tx);
-	CERROR("%s: can't convert to new fid: rc = %d\n", o->od_svname, rc);
 	RETURN(rc);
 }
 
@@ -861,4 +757,142 @@ int osd_options_init(void)
 	return 0;
 }
 
+/*
+ * the following set of functions are used to maintain per-thread
+ * cache of FID->ino mapping. this mechanism is used to avoid
+ * expensive LU/OI lookups.
+ */
+struct osd_idmap_cache *osd_idc_find(const struct lu_env *env,
+				     struct osd_device *osd,
+				     const struct lu_fid *fid)
+{
+	struct osd_thread_info *oti = osd_oti_get(env);
+	struct osd_idmap_cache *idc = oti->oti_ins_cache;
+	int i;
+
+	for (i = 0; i < oti->oti_ins_cache_used; i++) {
+		if (!lu_fid_eq(&idc[i].oic_fid, fid))
+			continue;
+		if (idc[i].oic_dev != osd)
+			continue;
+
+		return idc + i;
+	}
+
+	return NULL;
+}
+
+struct osd_idmap_cache *osd_idc_add(const struct lu_env *env,
+				    struct osd_device *osd,
+				    const struct lu_fid *fid)
+{
+	struct osd_thread_info *oti = osd_oti_get(env);
+	struct osd_idmap_cache *idc;
+	int i;
+
+	if (unlikely(oti->oti_ins_cache_used >= oti->oti_ins_cache_size)) {
+		i = oti->oti_ins_cache_size * 2;
+		LASSERT(i < 1000);
+		if (i == 0)
+			i = OSD_INS_CACHE_SIZE;
+		OBD_ALLOC(idc, sizeof(*idc) * i);
+		if (idc == NULL)
+			return ERR_PTR(-ENOMEM);
+		if (oti->oti_ins_cache != NULL) {
+			memcpy(idc, oti->oti_ins_cache,
+			       oti->oti_ins_cache_used * sizeof(*idc));
+			OBD_FREE(oti->oti_ins_cache,
+				 oti->oti_ins_cache_used * sizeof(*idc));
+		}
+		oti->oti_ins_cache = idc;
+		oti->oti_ins_cache_size = i;
+	}
 
+	idc = &oti->oti_ins_cache[oti->oti_ins_cache_used++];
+	idc->oic_fid = *fid;
+	idc->oic_dev = osd;
+	idc->oic_dnode = 0;
+	idc->oic_remote = 0;
+
+	return idc;
+}
+
+/**
+ * Lookup mapping for the given fid in the cache
+ *
+ * Initialize a new one if not found. the initialization checks whether
+ * the object is local or remote. for the local objects, OI is used to
+ * learn dnode#. the function is used when the caller has no information
+ * about the object, e.g. at dt_insert().
+ */
+struct osd_idmap_cache *osd_idc_find_or_init(const struct lu_env *env,
+					     struct osd_device *osd,
+					     const struct lu_fid *fid)
+{
+	struct osd_idmap_cache *idc;
+	int rc;
+
+	LASSERT(!fid_is_acct(fid));
+
+	idc = osd_idc_find(env, osd, fid);
+	if (idc != NULL)
+		return idc;
+
+	/* new mapping is needed */
+	idc = osd_idc_add(env, osd, fid);
+	if (IS_ERR(idc))
+		return idc;
+
+	/* initialize it */
+	rc = osd_remote_fid(env, osd, fid);
+	if (unlikely(rc < 0))
+		return ERR_PTR(rc);
+
+	if (rc == 0) {
+		/* the object is local, lookup in OI */
+		uint64_t dnode;
+
+		rc = osd_fid_lookup(env, osd, fid, &dnode);
+		if (unlikely(rc < 0)) {
+			CERROR("%s: can't lookup: rc = %d\n",
+			       osd->od_svname, rc);
+			return ERR_PTR(rc);
+		}
+		LASSERT(dnode < (1ULL << DN_MAX_OBJECT_SHIFT));
+		idc->oic_dnode = dnode;
+	} else {
+		/* the object is remote */
+		idc->oic_remote = 1;
+	}
+
+	return idc;
+}
+
+/*
+ * lookup mapping for given FID and fill it from the given object.
+ * the object is local by definition.
+ */
+int osd_idc_find_and_init(const struct lu_env *env, struct osd_device *osd,
+			  struct osd_object *obj)
+{
+	const struct lu_fid *fid = lu_object_fid(&obj->oo_dt.do_lu);
+	struct osd_idmap_cache *idc;
+
+	idc = osd_idc_find(env, osd, fid);
+	if (idc != NULL) {
+		if (obj->oo_dn == NULL)
+			return 0;
+		idc->oic_dnode = obj->oo_dn->dn_object;
+		return 0;
+	}
+
+	/* new mapping is needed */
+	idc = osd_idc_add(env, osd, fid);
+	if (IS_ERR(idc))
+		return PTR_ERR(idc);
+
+	if (obj->oo_dn)
+		idc->oic_dnode = obj->oo_dn->dn_object;
+
+	return 0;
+}