1 /* 2 * linux/fs/nfs/callback_proc.c 3 * 4 * Copyright (C) 2004 Trond Myklebust 5 * 6 * NFSv4 callback procedures 7 */ 8 #include <linux/nfs4.h> 9 #include <linux/nfs_fs.h> 10 #include <linux/slab.h> 11 #include <linux/rcupdate.h> 12 #include "nfs4_fs.h" 13 #include "callback.h" 14 #include "delegation.h" 15 #include "internal.h" 16 #include "pnfs.h" 17 #include "nfs4session.h" 18 #include "nfs4trace.h" 19 20 #define NFSDBG_FACILITY NFSDBG_CALLBACK 21 22 __be32 nfs4_callback_getattr(struct cb_getattrargs *args, 23 struct cb_getattrres *res, 24 struct cb_process_state *cps) 25 { 26 struct nfs_delegation *delegation; 27 struct nfs_inode *nfsi; 28 struct inode *inode; 29 30 res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION); 31 if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */ 32 goto out; 33 34 res->bitmap[0] = res->bitmap[1] = 0; 35 res->status = htonl(NFS4ERR_BADHANDLE); 36 37 dprintk_rcu("NFS: GETATTR callback request from %s\n", 38 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR)); 39 40 inode = nfs_delegation_find_inode(cps->clp, &args->fh); 41 if (inode == NULL) { 42 trace_nfs4_cb_getattr(cps->clp, &args->fh, NULL, 43 -ntohl(res->status)); 44 goto out; 45 } 46 nfsi = NFS_I(inode); 47 rcu_read_lock(); 48 delegation = rcu_dereference(nfsi->delegation); 49 if (delegation == NULL || (delegation->type & FMODE_WRITE) == 0) 50 goto out_iput; 51 res->size = i_size_read(inode); 52 res->change_attr = delegation->change_attr; 53 if (nfsi->nrequests != 0) 54 res->change_attr++; 55 res->ctime = inode->i_ctime; 56 res->mtime = inode->i_mtime; 57 res->bitmap[0] = (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE) & 58 args->bitmap[0]; 59 res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY) & 60 args->bitmap[1]; 61 res->status = 0; 62 out_iput: 63 rcu_read_unlock(); 64 trace_nfs4_cb_getattr(cps->clp, &args->fh, inode, -ntohl(res->status)); 65 iput(inode); 66 out: 67 dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status)); 68 return res->status; 69 } 70 71 __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy, 72 struct cb_process_state *cps) 73 { 74 struct inode *inode; 75 __be32 res; 76 77 res = htonl(NFS4ERR_OP_NOT_IN_SESSION); 78 if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */ 79 goto out; 80 81 dprintk_rcu("NFS: RECALL callback request from %s\n", 82 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR)); 83 84 res = htonl(NFS4ERR_BADHANDLE); 85 inode = nfs_delegation_find_inode(cps->clp, &args->fh); 86 if (inode == NULL) { 87 trace_nfs4_cb_recall(cps->clp, &args->fh, NULL, 88 &args->stateid, -ntohl(res)); 89 goto out; 90 } 91 /* Set up a helper thread to actually return the delegation */ 92 switch (nfs_async_inode_return_delegation(inode, &args->stateid)) { 93 case 0: 94 res = 0; 95 break; 96 case -ENOENT: 97 res = htonl(NFS4ERR_BAD_STATEID); 98 break; 99 default: 100 res = htonl(NFS4ERR_RESOURCE); 101 } 102 trace_nfs4_cb_recall(cps->clp, &args->fh, inode, 103 &args->stateid, -ntohl(res)); 104 iput(inode); 105 out: 106 dprintk("%s: exit with status = %d\n", __func__, ntohl(res)); 107 return res; 108 } 109 110 #if defined(CONFIG_NFS_V4_1) 111 112 /* 113 * Lookup a layout by filehandle. 114 * 115 * Note: gets a refcount on the layout hdr and on its respective inode. 116 * Caller must put the layout hdr and the inode. 117 * 118 * TODO: keep track of all layouts (and delegations) in a hash table 119 * hashed by filehandle. 120 */ 121 static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp, 122 struct nfs_fh *fh) 123 { 124 struct nfs_server *server; 125 struct nfs_inode *nfsi; 126 struct inode *ino; 127 struct pnfs_layout_hdr *lo; 128 129 restart: 130 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { 131 list_for_each_entry(lo, &server->layouts, plh_layouts) { 132 nfsi = NFS_I(lo->plh_inode); 133 if (nfs_compare_fh(fh, &nfsi->fh)) 134 continue; 135 if (nfsi->layout != lo) 136 continue; 137 ino = igrab(lo->plh_inode); 138 if (!ino) 139 break; 140 spin_lock(&ino->i_lock); 141 /* Is this layout in the process of being freed? */ 142 if (nfsi->layout != lo) { 143 spin_unlock(&ino->i_lock); 144 iput(ino); 145 goto restart; 146 } 147 pnfs_get_layout_hdr(lo); 148 spin_unlock(&ino->i_lock); 149 return lo; 150 } 151 } 152 153 return NULL; 154 } 155 156 static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client *clp, 157 struct nfs_fh *fh) 158 { 159 struct pnfs_layout_hdr *lo; 160 161 spin_lock(&clp->cl_lock); 162 rcu_read_lock(); 163 lo = get_layout_by_fh_locked(clp, fh); 164 rcu_read_unlock(); 165 spin_unlock(&clp->cl_lock); 166 167 return lo; 168 } 169 170 /* 171 * Enforce RFC5661 section 12.5.5.2.1. (Layout Recall and Return Sequencing) 172 */ 173 static u32 pnfs_check_callback_stateid(struct pnfs_layout_hdr *lo, 174 const nfs4_stateid *new) 175 { 176 u32 oldseq, newseq; 177 178 /* Is the stateid still not initialised? */ 179 if (!pnfs_layout_is_valid(lo)) 180 return NFS4ERR_DELAY; 181 182 /* Mismatched stateid? */ 183 if (!nfs4_stateid_match_other(&lo->plh_stateid, new)) 184 return NFS4ERR_BAD_STATEID; 185 186 newseq = be32_to_cpu(new->seqid); 187 /* Are we already in a layout recall situation? */ 188 if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) && 189 lo->plh_return_seq != 0) { 190 if (newseq < lo->plh_return_seq) 191 return NFS4ERR_OLD_STATEID; 192 if (newseq > lo->plh_return_seq) 193 return NFS4ERR_DELAY; 194 goto out; 195 } 196 197 /* Check that the stateid matches what we think it should be. */ 198 oldseq = be32_to_cpu(lo->plh_stateid.seqid); 199 if (newseq > oldseq + 1) 200 return NFS4ERR_DELAY; 201 /* Crazy server! */ 202 if (newseq <= oldseq) 203 return NFS4ERR_OLD_STATEID; 204 out: 205 return NFS_OK; 206 } 207 208 static u32 initiate_file_draining(struct nfs_client *clp, 209 struct cb_layoutrecallargs *args) 210 { 211 struct inode *ino; 212 struct pnfs_layout_hdr *lo; 213 u32 rv = NFS4ERR_NOMATCHING_LAYOUT; 214 LIST_HEAD(free_me_list); 215 216 lo = get_layout_by_fh(clp, &args->cbl_fh); 217 if (!lo) { 218 trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, NULL, 219 &args->cbl_stateid, -rv); 220 goto out; 221 } 222 223 ino = lo->plh_inode; 224 pnfs_layoutcommit_inode(ino, false); 225 226 227 spin_lock(&ino->i_lock); 228 rv = pnfs_check_callback_stateid(lo, &args->cbl_stateid); 229 if (rv != NFS_OK) 230 goto unlock; 231 pnfs_set_layout_stateid(lo, &args->cbl_stateid, true); 232 233 /* 234 * Enforce RFC5661 Section 12.5.5.2.1.5 (Bulk Recall and Return) 235 */ 236 if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) { 237 rv = NFS4ERR_DELAY; 238 goto unlock; 239 } 240 241 if (pnfs_mark_matching_lsegs_return(lo, &free_me_list, 242 &args->cbl_range, 243 be32_to_cpu(args->cbl_stateid.seqid))) { 244 rv = NFS4_OK; 245 goto unlock; 246 } 247 248 /* Embrace your forgetfulness! */ 249 rv = NFS4ERR_NOMATCHING_LAYOUT; 250 251 if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) { 252 NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, 253 &args->cbl_range); 254 } 255 unlock: 256 spin_unlock(&ino->i_lock); 257 pnfs_free_lseg_list(&free_me_list); 258 /* Free all lsegs that are attached to commit buckets */ 259 nfs_commit_inode(ino, 0); 260 pnfs_put_layout_hdr(lo); 261 trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, ino, 262 &args->cbl_stateid, -rv); 263 iput(ino); 264 out: 265 return rv; 266 } 267 268 static u32 initiate_bulk_draining(struct nfs_client *clp, 269 struct cb_layoutrecallargs *args) 270 { 271 int stat; 272 273 if (args->cbl_recall_type == RETURN_FSID) 274 stat = pnfs_destroy_layouts_byfsid(clp, &args->cbl_fsid, true); 275 else 276 stat = pnfs_destroy_layouts_byclid(clp, true); 277 if (stat != 0) 278 return NFS4ERR_DELAY; 279 return NFS4ERR_NOMATCHING_LAYOUT; 280 } 281 282 static u32 do_callback_layoutrecall(struct nfs_client *clp, 283 struct cb_layoutrecallargs *args) 284 { 285 u32 res; 286 287 dprintk("%s enter, type=%i\n", __func__, args->cbl_recall_type); 288 if (args->cbl_recall_type == RETURN_FILE) 289 res = initiate_file_draining(clp, args); 290 else 291 res = initiate_bulk_draining(clp, args); 292 dprintk("%s returning %i\n", __func__, res); 293 return res; 294 295 } 296 297 __be32 nfs4_callback_layoutrecall(struct cb_layoutrecallargs *args, 298 void *dummy, struct cb_process_state *cps) 299 { 300 u32 res; 301 302 dprintk("%s: -->\n", __func__); 303 304 if (cps->clp) 305 res = do_callback_layoutrecall(cps->clp, args); 306 else 307 res = NFS4ERR_OP_NOT_IN_SESSION; 308 309 dprintk("%s: exit with status = %d\n", __func__, res); 310 return cpu_to_be32(res); 311 } 312 313 static void pnfs_recall_all_layouts(struct nfs_client *clp) 314 { 315 struct cb_layoutrecallargs args; 316 317 /* Pretend we got a CB_LAYOUTRECALL(ALL) */ 318 memset(&args, 0, sizeof(args)); 319 args.cbl_recall_type = RETURN_ALL; 320 /* FIXME we ignore errors, what should we do? */ 321 do_callback_layoutrecall(clp, &args); 322 } 323 324 __be32 nfs4_callback_devicenotify(struct cb_devicenotifyargs *args, 325 void *dummy, struct cb_process_state *cps) 326 { 327 int i; 328 __be32 res = 0; 329 struct nfs_client *clp = cps->clp; 330 struct nfs_server *server = NULL; 331 332 dprintk("%s: -->\n", __func__); 333 334 if (!clp) { 335 res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION); 336 goto out; 337 } 338 339 for (i = 0; i < args->ndevs; i++) { 340 struct cb_devicenotifyitem *dev = &args->devs[i]; 341 342 if (!server || 343 server->pnfs_curr_ld->id != dev->cbd_layout_type) { 344 rcu_read_lock(); 345 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) 346 if (server->pnfs_curr_ld && 347 server->pnfs_curr_ld->id == dev->cbd_layout_type) { 348 rcu_read_unlock(); 349 goto found; 350 } 351 rcu_read_unlock(); 352 dprintk("%s: layout type %u not found\n", 353 __func__, dev->cbd_layout_type); 354 continue; 355 } 356 357 found: 358 nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id); 359 } 360 361 out: 362 kfree(args->devs); 363 dprintk("%s: exit with status = %u\n", 364 __func__, be32_to_cpu(res)); 365 return res; 366 } 367 368 /* 369 * Validate the sequenceID sent by the server. 370 * Return success if the sequenceID is one more than what we last saw on 371 * this slot, accounting for wraparound. Increments the slot's sequence. 372 * 373 * We don't yet implement a duplicate request cache, instead we set the 374 * back channel ca_maxresponsesize_cached to zero. This is OK for now 375 * since we only currently implement idempotent callbacks anyway. 376 * 377 * We have a single slot backchannel at this time, so we don't bother 378 * checking the used_slots bit array on the table. The lower layer guarantees 379 * a single outstanding callback request at a time. 380 */ 381 static __be32 382 validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot, 383 const struct cb_sequenceargs * args) 384 { 385 dprintk("%s enter. slotid %u seqid %u, slot table seqid: %u\n", 386 __func__, args->csa_slotid, args->csa_sequenceid, slot->seq_nr); 387 388 if (args->csa_slotid > tbl->server_highest_slotid) 389 return htonl(NFS4ERR_BADSLOT); 390 391 /* Replay */ 392 if (args->csa_sequenceid == slot->seq_nr) { 393 dprintk("%s seqid %u is a replay\n", 394 __func__, args->csa_sequenceid); 395 if (nfs4_test_locked_slot(tbl, slot->slot_nr)) 396 return htonl(NFS4ERR_DELAY); 397 /* Signal process_op to set this error on next op */ 398 if (args->csa_cachethis == 0) 399 return htonl(NFS4ERR_RETRY_UNCACHED_REP); 400 401 /* Liar! We never allowed you to set csa_cachethis != 0 */ 402 return htonl(NFS4ERR_SEQ_FALSE_RETRY); 403 } 404 405 /* Wraparound */ 406 if (unlikely(slot->seq_nr == 0xFFFFFFFFU)) { 407 if (args->csa_sequenceid == 1) 408 return htonl(NFS4_OK); 409 } else if (likely(args->csa_sequenceid == slot->seq_nr + 1)) 410 return htonl(NFS4_OK); 411 412 /* Misordered request */ 413 return htonl(NFS4ERR_SEQ_MISORDERED); 414 } 415 416 /* 417 * For each referring call triple, check the session's slot table for 418 * a match. If the slot is in use and the sequence numbers match, the 419 * client is still waiting for a response to the original request. 420 */ 421 static bool referring_call_exists(struct nfs_client *clp, 422 uint32_t nrclists, 423 struct referring_call_list *rclists) 424 { 425 bool status = 0; 426 int i, j; 427 struct nfs4_session *session; 428 struct nfs4_slot_table *tbl; 429 struct referring_call_list *rclist; 430 struct referring_call *ref; 431 432 /* 433 * XXX When client trunking is implemented, this becomes 434 * a session lookup from within the loop 435 */ 436 session = clp->cl_session; 437 tbl = &session->fc_slot_table; 438 439 for (i = 0; i < nrclists; i++) { 440 rclist = &rclists[i]; 441 if (memcmp(session->sess_id.data, 442 rclist->rcl_sessionid.data, 443 NFS4_MAX_SESSIONID_LEN) != 0) 444 continue; 445 446 for (j = 0; j < rclist->rcl_nrefcalls; j++) { 447 ref = &rclist->rcl_refcalls[j]; 448 449 dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u " 450 "slotid %u\n", __func__, 451 ((u32 *)&rclist->rcl_sessionid.data)[0], 452 ((u32 *)&rclist->rcl_sessionid.data)[1], 453 ((u32 *)&rclist->rcl_sessionid.data)[2], 454 ((u32 *)&rclist->rcl_sessionid.data)[3], 455 ref->rc_sequenceid, ref->rc_slotid); 456 457 status = nfs4_slot_wait_on_seqid(tbl, ref->rc_slotid, 458 ref->rc_sequenceid, HZ >> 1) < 0; 459 if (status) 460 goto out; 461 } 462 } 463 464 out: 465 return status; 466 } 467 468 __be32 nfs4_callback_sequence(struct cb_sequenceargs *args, 469 struct cb_sequenceres *res, 470 struct cb_process_state *cps) 471 { 472 struct nfs4_slot_table *tbl; 473 struct nfs4_slot *slot; 474 struct nfs_client *clp; 475 int i; 476 __be32 status = htonl(NFS4ERR_BADSESSION); 477 478 clp = nfs4_find_client_sessionid(cps->net, args->csa_addr, 479 &args->csa_sessionid, cps->minorversion); 480 if (clp == NULL) 481 goto out; 482 483 if (!(clp->cl_session->flags & SESSION4_BACK_CHAN)) 484 goto out; 485 486 tbl = &clp->cl_session->bc_slot_table; 487 488 /* Set up res before grabbing the spinlock */ 489 memcpy(&res->csr_sessionid, &args->csa_sessionid, 490 sizeof(res->csr_sessionid)); 491 res->csr_sequenceid = args->csa_sequenceid; 492 res->csr_slotid = args->csa_slotid; 493 494 spin_lock(&tbl->slot_tbl_lock); 495 /* state manager is resetting the session */ 496 if (test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state)) { 497 status = htonl(NFS4ERR_DELAY); 498 /* Return NFS4ERR_BADSESSION if we're draining the session 499 * in order to reset it. 500 */ 501 if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state)) 502 status = htonl(NFS4ERR_BADSESSION); 503 goto out_unlock; 504 } 505 506 status = htonl(NFS4ERR_BADSLOT); 507 slot = nfs4_lookup_slot(tbl, args->csa_slotid); 508 if (IS_ERR(slot)) 509 goto out_unlock; 510 511 res->csr_highestslotid = tbl->server_highest_slotid; 512 res->csr_target_highestslotid = tbl->target_highest_slotid; 513 514 status = validate_seqid(tbl, slot, args); 515 if (status) 516 goto out_unlock; 517 if (!nfs4_try_to_lock_slot(tbl, slot)) { 518 status = htonl(NFS4ERR_DELAY); 519 goto out_unlock; 520 } 521 cps->slot = slot; 522 523 /* The ca_maxresponsesize_cached is 0 with no DRC */ 524 if (args->csa_cachethis != 0) { 525 status = htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE); 526 goto out_unlock; 527 } 528 529 /* 530 * Check for pending referring calls. If a match is found, a 531 * related callback was received before the response to the original 532 * call. 533 */ 534 if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) { 535 status = htonl(NFS4ERR_DELAY); 536 goto out_unlock; 537 } 538 539 /* 540 * RFC5661 20.9.3 541 * If CB_SEQUENCE returns an error, then the state of the slot 542 * (sequence ID, cached reply) MUST NOT change. 543 */ 544 slot->seq_nr = args->csa_sequenceid; 545 out_unlock: 546 spin_unlock(&tbl->slot_tbl_lock); 547 548 out: 549 cps->clp = clp; /* put in nfs4_callback_compound */ 550 for (i = 0; i < args->csa_nrclists; i++) 551 kfree(args->csa_rclists[i].rcl_refcalls); 552 kfree(args->csa_rclists); 553 554 if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) { 555 cps->drc_status = status; 556 status = 0; 557 } else 558 res->csr_status = status; 559 560 trace_nfs4_cb_sequence(args, res, status); 561 dprintk("%s: exit with status = %d res->csr_status %d\n", __func__, 562 ntohl(status), ntohl(res->csr_status)); 563 return status; 564 } 565 566 static bool 567 validate_bitmap_values(unsigned long mask) 568 { 569 return (mask & ~RCA4_TYPE_MASK_ALL) == 0; 570 } 571 572 __be32 nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy, 573 struct cb_process_state *cps) 574 { 575 __be32 status; 576 fmode_t flags = 0; 577 578 status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION); 579 if (!cps->clp) /* set in cb_sequence */ 580 goto out; 581 582 dprintk_rcu("NFS: RECALL_ANY callback request from %s\n", 583 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR)); 584 585 status = cpu_to_be32(NFS4ERR_INVAL); 586 if (!validate_bitmap_values(args->craa_type_mask)) 587 goto out; 588 589 status = cpu_to_be32(NFS4_OK); 590 if (test_bit(RCA4_TYPE_MASK_RDATA_DLG, (const unsigned long *) 591 &args->craa_type_mask)) 592 flags = FMODE_READ; 593 if (test_bit(RCA4_TYPE_MASK_WDATA_DLG, (const unsigned long *) 594 &args->craa_type_mask)) 595 flags |= FMODE_WRITE; 596 if (test_bit(RCA4_TYPE_MASK_FILE_LAYOUT, (const unsigned long *) 597 &args->craa_type_mask)) 598 pnfs_recall_all_layouts(cps->clp); 599 if (flags) 600 nfs_expire_unused_delegation_types(cps->clp, flags); 601 out: 602 dprintk("%s: exit with status = %d\n", __func__, ntohl(status)); 603 return status; 604 } 605 606 /* Reduce the fore channel's max_slots to the target value */ 607 __be32 nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy, 608 struct cb_process_state *cps) 609 { 610 struct nfs4_slot_table *fc_tbl; 611 __be32 status; 612 613 status = htonl(NFS4ERR_OP_NOT_IN_SESSION); 614 if (!cps->clp) /* set in cb_sequence */ 615 goto out; 616 617 dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target highest slotid %u\n", 618 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR), 619 args->crsa_target_highest_slotid); 620 621 fc_tbl = &cps->clp->cl_session->fc_slot_table; 622 623 status = htonl(NFS4_OK); 624 625 nfs41_set_target_slotid(fc_tbl, args->crsa_target_highest_slotid); 626 nfs41_notify_server(cps->clp); 627 out: 628 dprintk("%s: exit with status = %d\n", __func__, ntohl(status)); 629 return status; 630 } 631 632 __be32 nfs4_callback_notify_lock(struct cb_notify_lock_args *args, void *dummy, 633 struct cb_process_state *cps) 634 { 635 if (!cps->clp) /* set in cb_sequence */ 636 return htonl(NFS4ERR_OP_NOT_IN_SESSION); 637 638 dprintk_rcu("NFS: CB_NOTIFY_LOCK request from %s\n", 639 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR)); 640 641 /* Don't wake anybody if the string looked bogus */ 642 if (args->cbnl_valid) 643 __wake_up(&cps->clp->cl_lock_waitq, TASK_NORMAL, 0, args); 644 645 return htonl(NFS4_OK); 646 } 647 #endif /* CONFIG_NFS_V4_1 */ 648