1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Device operations for the pnfs nfs4 file layout driver. 4 * 5 * Copyright (c) 2014, Primary Data, Inc. All rights reserved. 6 * 7 * Tao Peng <bergwolf@primarydata.com> 8 */ 9 10 #include <linux/nfs_fs.h> 11 #include <linux/vmalloc.h> 12 #include <linux/module.h> 13 #include <linux/sunrpc/addr.h> 14 15 #include "../internal.h" 16 #include "../nfs4session.h" 17 #include "flexfilelayout.h" 18 19 #define NFSDBG_FACILITY NFSDBG_PNFS_LD 20 21 static unsigned int dataserver_timeo = NFS_DEF_TCP_TIMEO; 22 static unsigned int dataserver_retrans; 23 24 static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg); 25 26 void nfs4_ff_layout_put_deviceid(struct nfs4_ff_layout_ds *mirror_ds) 27 { 28 if (!IS_ERR_OR_NULL(mirror_ds)) 29 nfs4_put_deviceid_node(&mirror_ds->id_node); 30 } 31 32 void nfs4_ff_layout_free_deviceid(struct nfs4_ff_layout_ds *mirror_ds) 33 { 34 nfs4_print_deviceid(&mirror_ds->id_node.deviceid); 35 nfs4_pnfs_ds_put(mirror_ds->ds); 36 kfree(mirror_ds->ds_versions); 37 kfree_rcu(mirror_ds, id_node.rcu); 38 } 39 40 /* Decode opaque device data and construct new_ds using it */ 41 struct nfs4_ff_layout_ds * 42 nfs4_ff_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev, 43 gfp_t gfp_flags) 44 { 45 struct xdr_stream stream; 46 struct xdr_buf buf; 47 struct folio *scratch; 48 struct list_head dsaddrs; 49 struct nfs4_pnfs_ds_addr *da; 50 struct nfs4_ff_layout_ds *new_ds = NULL; 51 struct nfs4_ff_ds_version *ds_versions = NULL; 52 struct net *net = server->nfs_client->cl_net; 53 u32 mp_count; 54 u32 version_count; 55 __be32 *p; 56 int i, ret = -ENOMEM; 57 58 /* set up xdr stream */ 59 scratch = folio_alloc(gfp_flags, 0); 60 if (!scratch) 61 goto out_err; 62 63 new_ds = kzalloc_obj(struct nfs4_ff_layout_ds, gfp_flags); 64 if (!new_ds) 65 goto out_scratch; 66 67 nfs4_init_deviceid_node(&new_ds->id_node, 68 server, 69 &pdev->dev_id); 70 INIT_LIST_HEAD(&dsaddrs); 71 72 xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen); 73 xdr_set_scratch_folio(&stream, scratch); 74 75 /* multipath count */ 76 p = xdr_inline_decode(&stream, 4); 77 if (unlikely(!p)) 78 goto out_err_drain_dsaddrs; 79 mp_count = be32_to_cpup(p); 80 dprintk("%s: multipath ds count %d\n", __func__, mp_count); 81 82 for (i = 0; i < mp_count; i++) { 83 /* multipath ds */ 84 da = nfs4_decode_mp_ds_addr(net, &stream, gfp_flags); 85 if (da) 86 list_add_tail(&da->da_node, &dsaddrs); 87 } 88 if (list_empty(&dsaddrs)) { 89 dprintk("%s: no suitable DS addresses found\n", 90 __func__); 91 ret = -ENOMEDIUM; 92 goto out_err_drain_dsaddrs; 93 } 94 95 /* version count */ 96 p = xdr_inline_decode(&stream, 4); 97 if (unlikely(!p)) 98 goto out_err_drain_dsaddrs; 99 version_count = be32_to_cpup(p); 100 dprintk("%s: version count %d\n", __func__, version_count); 101 102 ds_versions = kzalloc_objs(struct nfs4_ff_ds_version, version_count, 103 gfp_flags); 104 if (!ds_versions) 105 goto out_err_drain_dsaddrs; 106 107 for (i = 0; i < version_count; i++) { 108 /* 20 = version(4) + minor_version(4) + rsize(4) + wsize(4) + 109 * tightly_coupled(4) */ 110 p = xdr_inline_decode(&stream, 20); 111 if (unlikely(!p)) 112 goto out_err_drain_dsaddrs; 113 ds_versions[i].version = be32_to_cpup(p++); 114 ds_versions[i].minor_version = be32_to_cpup(p++); 115 ds_versions[i].rsize = nfs_io_size(be32_to_cpup(p++), 116 server->nfs_client->cl_proto); 117 ds_versions[i].wsize = nfs_io_size(be32_to_cpup(p++), 118 server->nfs_client->cl_proto); 119 ds_versions[i].tightly_coupled = be32_to_cpup(p); 120 121 if (ds_versions[i].rsize > NFS_MAX_FILE_IO_SIZE) 122 ds_versions[i].rsize = NFS_MAX_FILE_IO_SIZE; 123 if (ds_versions[i].wsize > NFS_MAX_FILE_IO_SIZE) 124 ds_versions[i].wsize = NFS_MAX_FILE_IO_SIZE; 125 126 /* 127 * check for valid major/minor combination. 128 * currently we support dataserver which talk: 129 * v3, v4.0, v4.1, v4.2 130 */ 131 if (!((ds_versions[i].version == 3 && ds_versions[i].minor_version == 0) || 132 (ds_versions[i].version == 4 && ds_versions[i].minor_version < 3))) { 133 dprintk("%s: [%d] unsupported ds version %d-%d\n", __func__, 134 i, ds_versions[i].version, 135 ds_versions[i].minor_version); 136 ret = -EPROTONOSUPPORT; 137 goto out_err_drain_dsaddrs; 138 } 139 140 dprintk("%s: [%d] vers %u minor_ver %u rsize %u wsize %u coupled %d\n", 141 __func__, i, ds_versions[i].version, 142 ds_versions[i].minor_version, 143 ds_versions[i].rsize, 144 ds_versions[i].wsize, 145 ds_versions[i].tightly_coupled); 146 } 147 148 new_ds->ds_versions = ds_versions; 149 new_ds->ds_versions_cnt = version_count; 150 151 new_ds->ds = nfs4_pnfs_ds_add(net, &dsaddrs, gfp_flags); 152 if (!new_ds->ds) 153 goto out_err_drain_dsaddrs; 154 155 /* If DS was already in cache, free ds addrs */ 156 while (!list_empty(&dsaddrs)) { 157 da = list_first_entry(&dsaddrs, 158 struct nfs4_pnfs_ds_addr, 159 da_node); 160 list_del_init(&da->da_node); 161 kfree(da->da_remotestr); 162 kfree(da); 163 } 164 165 folio_put(scratch); 166 return new_ds; 167 168 out_err_drain_dsaddrs: 169 while (!list_empty(&dsaddrs)) { 170 da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr, 171 da_node); 172 list_del_init(&da->da_node); 173 kfree(da->da_remotestr); 174 kfree(da); 175 } 176 177 kfree(ds_versions); 178 out_scratch: 179 folio_put(scratch); 180 out_err: 181 kfree(new_ds); 182 183 dprintk("%s ERROR: returning %d\n", __func__, ret); 184 return NULL; 185 } 186 187 static void extend_ds_error(struct nfs4_ff_layout_ds_err *err, 188 u64 offset, u64 length) 189 { 190 u64 end; 191 192 end = max_t(u64, pnfs_end_offset(err->offset, err->length), 193 pnfs_end_offset(offset, length)); 194 err->offset = min_t(u64, err->offset, offset); 195 err->length = end - err->offset; 196 } 197 198 static int 199 ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1, 200 const struct nfs4_ff_layout_ds_err *e2) 201 { 202 int ret; 203 204 if (e1->opnum != e2->opnum) 205 return e1->opnum < e2->opnum ? -1 : 1; 206 if (e1->status != e2->status) 207 return e1->status < e2->status ? -1 : 1; 208 ret = memcmp(e1->stateid.data, e2->stateid.data, 209 sizeof(e1->stateid.data)); 210 if (ret != 0) 211 return ret; 212 ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid)); 213 if (ret != 0) 214 return ret; 215 if (pnfs_end_offset(e1->offset, e1->length) < e2->offset) 216 return -1; 217 if (e1->offset > pnfs_end_offset(e2->offset, e2->length)) 218 return 1; 219 /* If ranges overlap or are contiguous, they are the same */ 220 return 0; 221 } 222 223 static void 224 ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo, 225 struct nfs4_ff_layout_ds_err *dserr) 226 { 227 struct nfs4_ff_layout_ds_err *err, *tmp; 228 struct list_head *head = &flo->error_list; 229 int match; 230 231 /* Do insertion sort w/ merges */ 232 list_for_each_entry_safe(err, tmp, &flo->error_list, list) { 233 match = ff_ds_error_match(err, dserr); 234 if (match < 0) 235 continue; 236 if (match > 0) { 237 /* Add entry "dserr" _before_ entry "err" */ 238 head = &err->list; 239 break; 240 } 241 /* Entries match, so merge "err" into "dserr" */ 242 extend_ds_error(dserr, err->offset, err->length); 243 list_replace(&err->list, &dserr->list); 244 kfree(err); 245 return; 246 } 247 248 list_add_tail(&dserr->list, head); 249 } 250 251 int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo, 252 struct nfs4_ff_layout_mirror *mirror, 253 u32 dss_id, u64 offset, u64 length, int status, 254 enum nfs_opnum4 opnum, gfp_t gfp_flags) 255 { 256 struct nfs4_ff_layout_ds_err *dserr; 257 258 if (status == 0) 259 return 0; 260 261 if (IS_ERR_OR_NULL(mirror->dss[dss_id].mirror_ds)) 262 return -EINVAL; 263 264 dserr = kmalloc_obj(*dserr, gfp_flags); 265 if (!dserr) 266 return -ENOMEM; 267 268 INIT_LIST_HEAD(&dserr->list); 269 dserr->offset = offset; 270 dserr->length = length; 271 dserr->status = status; 272 dserr->opnum = opnum; 273 nfs4_stateid_copy(&dserr->stateid, &mirror->dss[dss_id].stateid); 274 memcpy(&dserr->deviceid, &mirror->dss[dss_id].mirror_ds->id_node.deviceid, 275 NFS4_DEVICEID4_SIZE); 276 277 spin_lock(&flo->generic_hdr.plh_inode->i_lock); 278 ff_layout_add_ds_error_locked(flo, dserr); 279 spin_unlock(&flo->generic_hdr.plh_inode->i_lock); 280 return 0; 281 } 282 283 static const struct cred * 284 ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode, u32 dss_id) 285 { 286 const struct cred *cred, __rcu **pcred; 287 288 if (iomode == IOMODE_READ) 289 pcred = &mirror->dss[dss_id].ro_cred; 290 else 291 pcred = &mirror->dss[dss_id].rw_cred; 292 293 rcu_read_lock(); 294 do { 295 cred = rcu_dereference(*pcred); 296 if (!cred) 297 break; 298 299 cred = get_cred_rcu(cred); 300 } while(!cred); 301 rcu_read_unlock(); 302 return cred; 303 } 304 305 struct nfs_fh * 306 nfs4_ff_layout_select_ds_fh(struct nfs4_ff_layout_mirror *mirror, u32 dss_id) 307 { 308 /* FIXME: For now assume there is only 1 version available for the DS */ 309 return &mirror->dss[dss_id].fh_versions[0]; 310 } 311 312 void 313 nfs4_ff_layout_select_ds_stateid(const struct nfs4_ff_layout_mirror *mirror, 314 u32 dss_id, 315 nfs4_stateid *stateid) 316 { 317 if (nfs4_ff_layout_ds_version(mirror, dss_id) == 4) 318 nfs4_stateid_copy(stateid, &mirror->dss[dss_id].stateid); 319 } 320 321 static bool 322 ff_layout_init_mirror_ds(struct pnfs_layout_hdr *lo, 323 struct nfs4_ff_layout_mirror *mirror, 324 u32 dss_id) 325 { 326 if (mirror == NULL) 327 goto outerr; 328 if (mirror->dss[dss_id].mirror_ds == NULL) { 329 struct nfs4_deviceid_node *node; 330 struct nfs4_ff_layout_ds *mirror_ds = ERR_PTR(-ENODEV); 331 332 node = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), 333 &mirror->dss[dss_id].devid, lo->plh_lc_cred, 334 GFP_KERNEL); 335 if (node) 336 mirror_ds = FF_LAYOUT_MIRROR_DS(node); 337 338 /* check for race with another call to this function */ 339 if (cmpxchg(&mirror->dss[dss_id].mirror_ds, NULL, mirror_ds) && 340 mirror_ds != ERR_PTR(-ENODEV)) 341 nfs4_put_deviceid_node(node); 342 } 343 344 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 345 goto outerr; 346 347 return true; 348 outerr: 349 return false; 350 } 351 352 /** 353 * nfs4_ff_layout_prepare_ds - prepare a DS connection for an RPC call 354 * @lseg: the layout segment we're operating on 355 * @mirror: layout mirror describing the DS to use 356 * @dss_id: DS stripe id to select stripe to use 357 * @fail_return: return layout on connect failure? 358 * 359 * Try to prepare a DS connection to accept an RPC call. This involves 360 * selecting a mirror to use and connecting the client to it if it's not 361 * already connected. 362 * 363 * Since we only need a single functioning mirror to satisfy a read, we don't 364 * want to return the layout if there is one. For writes though, any down 365 * mirror should result in a LAYOUTRETURN. @fail_return is how we distinguish 366 * between the two cases. 367 * 368 * Returns a pointer to a connected DS object on success or NULL on failure. 369 */ 370 struct nfs4_pnfs_ds * 371 nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, 372 struct nfs4_ff_layout_mirror *mirror, 373 u32 dss_id, 374 bool fail_return) 375 { 376 struct nfs4_pnfs_ds *ds; 377 struct inode *ino = lseg->pls_layout->plh_inode; 378 struct nfs_server *s = NFS_SERVER(ino); 379 unsigned int max_payload; 380 int status = -EAGAIN; 381 382 if (!ff_layout_init_mirror_ds(lseg->pls_layout, mirror, dss_id)) 383 goto noconnect; 384 385 ds = mirror->dss[dss_id].mirror_ds->ds; 386 if (READ_ONCE(ds->ds_clp)) 387 goto out; 388 /* matching smp_wmb() in _nfs4_pnfs_v3/4_ds_connect */ 389 smp_rmb(); 390 391 /* FIXME: For now we assume the server sent only one version of NFS 392 * to use for the DS. 393 */ 394 status = nfs4_pnfs_ds_connect(s, ds, &mirror->dss[dss_id].mirror_ds->id_node, 395 dataserver_timeo, dataserver_retrans, 396 mirror->dss[dss_id].mirror_ds->ds_versions[0].version, 397 mirror->dss[dss_id].mirror_ds->ds_versions[0].minor_version); 398 399 /* connect success, check rsize/wsize limit */ 400 if (!status) { 401 /* 402 * ds_clp is put in destroy_ds(). 403 * keep ds_clp even if DS is local, so that if local IO cannot 404 * proceed somehow, we can fall back to NFS whenever we want. 405 */ 406 nfs_local_probe_async(ds->ds_clp); 407 max_payload = 408 nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient), 409 NULL); 410 if (mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize > max_payload) 411 mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize = max_payload; 412 if (mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize > max_payload) 413 mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize = max_payload; 414 goto out; 415 } 416 noconnect: 417 ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout), 418 mirror, dss_id, lseg->pls_range.offset, 419 lseg->pls_range.length, NFS4ERR_NXIO, 420 OP_ILLEGAL, GFP_NOIO); 421 ff_layout_send_layouterror(lseg); 422 if (fail_return || !ff_layout_has_available_ds(lseg)) 423 pnfs_error_mark_layout_for_return(ino, lseg); 424 ds = ERR_PTR(status); 425 out: 426 return ds; 427 } 428 429 const struct cred * 430 ff_layout_get_ds_cred(struct nfs4_ff_layout_mirror *mirror, 431 const struct pnfs_layout_range *range, 432 const struct cred *mdscred, 433 u32 dss_id) 434 { 435 const struct cred *cred; 436 437 if (mirror && !mirror->dss[dss_id].mirror_ds->ds_versions[0].tightly_coupled) { 438 cred = ff_layout_get_mirror_cred(mirror, range->iomode, dss_id); 439 if (!cred) 440 cred = get_cred(mdscred); 441 } else { 442 cred = get_cred(mdscred); 443 } 444 return cred; 445 } 446 447 /** 448 * nfs4_ff_find_or_create_ds_client - Find or create a DS rpc client 449 * @mirror: pointer to the mirror 450 * @ds_clp: nfs_client for the DS 451 * @inode: pointer to inode 452 * @dss_id: DS stripe id 453 * 454 * Find or create a DS rpc client with th MDS server rpc client auth flavor 455 * in the nfs_client cl_ds_clients list. 456 */ 457 struct rpc_clnt * 458 nfs4_ff_find_or_create_ds_client(struct nfs4_ff_layout_mirror *mirror, 459 struct nfs_client *ds_clp, struct inode *inode, 460 u32 dss_id) 461 { 462 switch (mirror->dss[dss_id].mirror_ds->ds_versions[0].version) { 463 case 3: 464 /* For NFSv3 DS, flavor is set when creating DS connections */ 465 return ds_clp->cl_rpcclient; 466 case 4: 467 return nfs4_find_or_create_ds_client(ds_clp, inode); 468 default: 469 BUG(); 470 } 471 } 472 473 void ff_layout_free_ds_ioerr(struct list_head *head) 474 { 475 struct nfs4_ff_layout_ds_err *err; 476 477 while (!list_empty(head)) { 478 err = list_first_entry(head, 479 struct nfs4_ff_layout_ds_err, 480 list); 481 list_del(&err->list); 482 kfree(err); 483 } 484 } 485 486 /* called with inode i_lock held */ 487 int ff_layout_encode_ds_ioerr(struct xdr_stream *xdr, const struct list_head *head) 488 { 489 struct nfs4_ff_layout_ds_err *err; 490 __be32 *p; 491 492 list_for_each_entry(err, head, list) { 493 /* offset(8) + length(8) + stateid(NFS4_STATEID_SIZE) 494 * + array length + deviceid(NFS4_DEVICEID4_SIZE) 495 * + status(4) + opnum(4) 496 */ 497 p = xdr_reserve_space(xdr, 498 28 + NFS4_STATEID_SIZE + NFS4_DEVICEID4_SIZE); 499 if (unlikely(!p)) 500 return -ENOBUFS; 501 p = xdr_encode_hyper(p, err->offset); 502 p = xdr_encode_hyper(p, err->length); 503 p = xdr_encode_opaque_fixed(p, &err->stateid, 504 NFS4_STATEID_SIZE); 505 /* Encode 1 error */ 506 *p++ = cpu_to_be32(1); 507 p = xdr_encode_opaque_fixed(p, &err->deviceid, 508 NFS4_DEVICEID4_SIZE); 509 *p++ = cpu_to_be32(err->status); 510 *p++ = cpu_to_be32(err->opnum); 511 dprintk("%s: offset %llu length %llu status %d op %d\n", 512 __func__, err->offset, err->length, err->status, 513 err->opnum); 514 } 515 516 return 0; 517 } 518 519 static 520 unsigned int do_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, 521 const struct pnfs_layout_range *range, 522 struct list_head *head, 523 unsigned int maxnum) 524 { 525 struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo); 526 struct inode *inode = lo->plh_inode; 527 struct nfs4_ff_layout_ds_err *err, *n; 528 unsigned int ret = 0; 529 530 spin_lock(&inode->i_lock); 531 list_for_each_entry_safe(err, n, &flo->error_list, list) { 532 if (!pnfs_is_range_intersecting(err->offset, 533 pnfs_end_offset(err->offset, err->length), 534 range->offset, 535 pnfs_end_offset(range->offset, range->length))) 536 continue; 537 if (!maxnum) 538 break; 539 list_move(&err->list, head); 540 maxnum--; 541 ret++; 542 } 543 spin_unlock(&inode->i_lock); 544 return ret; 545 } 546 547 unsigned int ff_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, 548 const struct pnfs_layout_range *range, 549 struct list_head *head, 550 unsigned int maxnum) 551 { 552 unsigned int ret; 553 554 ret = do_layout_fetch_ds_ioerr(lo, range, head, maxnum); 555 /* If we're over the max, discard all remaining entries */ 556 if (ret == maxnum) { 557 LIST_HEAD(discard); 558 do_layout_fetch_ds_ioerr(lo, range, &discard, -1); 559 ff_layout_free_ds_ioerr(&discard); 560 } 561 return ret; 562 } 563 564 static bool ff_read_layout_has_available_ds(struct pnfs_layout_segment *lseg) 565 { 566 struct nfs4_ff_layout_mirror *mirror; 567 struct nfs4_deviceid_node *devid; 568 u32 idx, dss_id; 569 570 for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { 571 mirror = FF_LAYOUT_COMP(lseg, idx); 572 if (!mirror) 573 continue; 574 for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) { 575 if (!mirror->dss[dss_id].mirror_ds) 576 return true; 577 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 578 continue; 579 devid = &mirror->dss[dss_id].mirror_ds->id_node; 580 if (!nfs4_test_deviceid_unavailable(devid)) 581 return true; 582 } 583 } 584 585 return false; 586 } 587 588 static bool ff_rw_layout_has_available_ds(struct pnfs_layout_segment *lseg) 589 { 590 struct nfs4_ff_layout_mirror *mirror; 591 struct nfs4_deviceid_node *devid; 592 u32 idx, dss_id; 593 594 for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { 595 mirror = FF_LAYOUT_COMP(lseg, idx); 596 if (!mirror) 597 return false; 598 for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) { 599 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 600 return false; 601 if (!mirror->dss[dss_id].mirror_ds) 602 continue; 603 devid = &mirror->dss[dss_id].mirror_ds->id_node; 604 if (nfs4_test_deviceid_unavailable(devid)) 605 return false; 606 } 607 } 608 609 return FF_LAYOUT_MIRROR_COUNT(lseg) != 0; 610 } 611 612 static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg) 613 { 614 if (lseg->pls_range.iomode == IOMODE_READ) 615 return ff_read_layout_has_available_ds(lseg); 616 /* Note: RW layout needs all mirrors available */ 617 return ff_rw_layout_has_available_ds(lseg); 618 } 619 620 bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg) 621 { 622 return ff_layout_no_fallback_to_mds(lseg) || 623 ff_layout_has_available_ds(lseg); 624 } 625 626 bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg) 627 { 628 return lseg->pls_range.iomode == IOMODE_RW && 629 ff_layout_no_read_on_rw(lseg); 630 } 631 632 module_param(dataserver_retrans, uint, 0644); 633 MODULE_PARM_DESC(dataserver_retrans, "The number of times the NFSv4.1 client " 634 "retries a request before it attempts further " 635 " recovery action."); 636 module_param(dataserver_timeo, uint, 0644); 637 MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the " 638 "NFSv4.1 client waits for a response from a " 639 " data server before it retries an NFS request."); 640