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(sizeof(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 = kcalloc(version_count, 103 sizeof(struct nfs4_ff_ds_version), 104 gfp_flags); 105 if (!ds_versions) 106 goto out_scratch; 107 108 for (i = 0; i < version_count; i++) { 109 /* 20 = version(4) + minor_version(4) + rsize(4) + wsize(4) + 110 * tightly_coupled(4) */ 111 p = xdr_inline_decode(&stream, 20); 112 if (unlikely(!p)) 113 goto out_err_drain_dsaddrs; 114 ds_versions[i].version = be32_to_cpup(p++); 115 ds_versions[i].minor_version = be32_to_cpup(p++); 116 ds_versions[i].rsize = nfs_io_size(be32_to_cpup(p++), 117 server->nfs_client->cl_proto); 118 ds_versions[i].wsize = nfs_io_size(be32_to_cpup(p++), 119 server->nfs_client->cl_proto); 120 ds_versions[i].tightly_coupled = be32_to_cpup(p); 121 122 if (ds_versions[i].rsize > NFS_MAX_FILE_IO_SIZE) 123 ds_versions[i].rsize = NFS_MAX_FILE_IO_SIZE; 124 if (ds_versions[i].wsize > NFS_MAX_FILE_IO_SIZE) 125 ds_versions[i].wsize = NFS_MAX_FILE_IO_SIZE; 126 127 /* 128 * check for valid major/minor combination. 129 * currently we support dataserver which talk: 130 * v3, v4.0, v4.1, v4.2 131 */ 132 if (!((ds_versions[i].version == 3 && ds_versions[i].minor_version == 0) || 133 (ds_versions[i].version == 4 && ds_versions[i].minor_version < 3))) { 134 dprintk("%s: [%d] unsupported ds version %d-%d\n", __func__, 135 i, ds_versions[i].version, 136 ds_versions[i].minor_version); 137 ret = -EPROTONOSUPPORT; 138 goto out_err_drain_dsaddrs; 139 } 140 141 dprintk("%s: [%d] vers %u minor_ver %u rsize %u wsize %u coupled %d\n", 142 __func__, i, ds_versions[i].version, 143 ds_versions[i].minor_version, 144 ds_versions[i].rsize, 145 ds_versions[i].wsize, 146 ds_versions[i].tightly_coupled); 147 } 148 149 new_ds->ds_versions = ds_versions; 150 new_ds->ds_versions_cnt = version_count; 151 152 new_ds->ds = nfs4_pnfs_ds_add(net, &dsaddrs, gfp_flags); 153 if (!new_ds->ds) 154 goto out_err_drain_dsaddrs; 155 156 /* If DS was already in cache, free ds addrs */ 157 while (!list_empty(&dsaddrs)) { 158 da = list_first_entry(&dsaddrs, 159 struct nfs4_pnfs_ds_addr, 160 da_node); 161 list_del_init(&da->da_node); 162 kfree(da->da_remotestr); 163 kfree(da); 164 } 165 166 folio_put(scratch); 167 return new_ds; 168 169 out_err_drain_dsaddrs: 170 while (!list_empty(&dsaddrs)) { 171 da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr, 172 da_node); 173 list_del_init(&da->da_node); 174 kfree(da->da_remotestr); 175 kfree(da); 176 } 177 178 kfree(ds_versions); 179 out_scratch: 180 folio_put(scratch); 181 out_err: 182 kfree(new_ds); 183 184 dprintk("%s ERROR: returning %d\n", __func__, ret); 185 return NULL; 186 } 187 188 static void extend_ds_error(struct nfs4_ff_layout_ds_err *err, 189 u64 offset, u64 length) 190 { 191 u64 end; 192 193 end = max_t(u64, pnfs_end_offset(err->offset, err->length), 194 pnfs_end_offset(offset, length)); 195 err->offset = min_t(u64, err->offset, offset); 196 err->length = end - err->offset; 197 } 198 199 static int 200 ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1, 201 const struct nfs4_ff_layout_ds_err *e2) 202 { 203 int ret; 204 205 if (e1->opnum != e2->opnum) 206 return e1->opnum < e2->opnum ? -1 : 1; 207 if (e1->status != e2->status) 208 return e1->status < e2->status ? -1 : 1; 209 ret = memcmp(e1->stateid.data, e2->stateid.data, 210 sizeof(e1->stateid.data)); 211 if (ret != 0) 212 return ret; 213 ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid)); 214 if (ret != 0) 215 return ret; 216 if (pnfs_end_offset(e1->offset, e1->length) < e2->offset) 217 return -1; 218 if (e1->offset > pnfs_end_offset(e2->offset, e2->length)) 219 return 1; 220 /* If ranges overlap or are contiguous, they are the same */ 221 return 0; 222 } 223 224 static void 225 ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo, 226 struct nfs4_ff_layout_ds_err *dserr) 227 { 228 struct nfs4_ff_layout_ds_err *err, *tmp; 229 struct list_head *head = &flo->error_list; 230 int match; 231 232 /* Do insertion sort w/ merges */ 233 list_for_each_entry_safe(err, tmp, &flo->error_list, list) { 234 match = ff_ds_error_match(err, dserr); 235 if (match < 0) 236 continue; 237 if (match > 0) { 238 /* Add entry "dserr" _before_ entry "err" */ 239 head = &err->list; 240 break; 241 } 242 /* Entries match, so merge "err" into "dserr" */ 243 extend_ds_error(dserr, err->offset, err->length); 244 list_replace(&err->list, &dserr->list); 245 kfree(err); 246 return; 247 } 248 249 list_add_tail(&dserr->list, head); 250 } 251 252 int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo, 253 struct nfs4_ff_layout_mirror *mirror, 254 u32 dss_id, u64 offset, u64 length, int status, 255 enum nfs_opnum4 opnum, gfp_t gfp_flags) 256 { 257 struct nfs4_ff_layout_ds_err *dserr; 258 259 if (status == 0) 260 return 0; 261 262 if (IS_ERR_OR_NULL(mirror->dss[dss_id].mirror_ds)) 263 return -EINVAL; 264 265 dserr = kmalloc(sizeof(*dserr), gfp_flags); 266 if (!dserr) 267 return -ENOMEM; 268 269 INIT_LIST_HEAD(&dserr->list); 270 dserr->offset = offset; 271 dserr->length = length; 272 dserr->status = status; 273 dserr->opnum = opnum; 274 nfs4_stateid_copy(&dserr->stateid, &mirror->dss[dss_id].stateid); 275 memcpy(&dserr->deviceid, &mirror->dss[dss_id].mirror_ds->id_node.deviceid, 276 NFS4_DEVICEID4_SIZE); 277 278 spin_lock(&flo->generic_hdr.plh_inode->i_lock); 279 ff_layout_add_ds_error_locked(flo, dserr); 280 spin_unlock(&flo->generic_hdr.plh_inode->i_lock); 281 return 0; 282 } 283 284 static const struct cred * 285 ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode, u32 dss_id) 286 { 287 const struct cred *cred, __rcu **pcred; 288 289 if (iomode == IOMODE_READ) 290 pcred = &mirror->dss[dss_id].ro_cred; 291 else 292 pcred = &mirror->dss[dss_id].rw_cred; 293 294 rcu_read_lock(); 295 do { 296 cred = rcu_dereference(*pcred); 297 if (!cred) 298 break; 299 300 cred = get_cred_rcu(cred); 301 } while(!cred); 302 rcu_read_unlock(); 303 return cred; 304 } 305 306 struct nfs_fh * 307 nfs4_ff_layout_select_ds_fh(struct nfs4_ff_layout_mirror *mirror, u32 dss_id) 308 { 309 /* FIXME: For now assume there is only 1 version available for the DS */ 310 return &mirror->dss[dss_id].fh_versions[0]; 311 } 312 313 void 314 nfs4_ff_layout_select_ds_stateid(const struct nfs4_ff_layout_mirror *mirror, 315 u32 dss_id, 316 nfs4_stateid *stateid) 317 { 318 if (nfs4_ff_layout_ds_version(mirror, dss_id) == 4) 319 nfs4_stateid_copy(stateid, &mirror->dss[dss_id].stateid); 320 } 321 322 static bool 323 ff_layout_init_mirror_ds(struct pnfs_layout_hdr *lo, 324 struct nfs4_ff_layout_mirror *mirror, 325 u32 dss_id) 326 { 327 if (mirror == NULL) 328 goto outerr; 329 if (mirror->dss[dss_id].mirror_ds == NULL) { 330 struct nfs4_deviceid_node *node; 331 struct nfs4_ff_layout_ds *mirror_ds = ERR_PTR(-ENODEV); 332 333 node = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), 334 &mirror->dss[dss_id].devid, lo->plh_lc_cred, 335 GFP_KERNEL); 336 if (node) 337 mirror_ds = FF_LAYOUT_MIRROR_DS(node); 338 339 /* check for race with another call to this function */ 340 if (cmpxchg(&mirror->dss[dss_id].mirror_ds, NULL, mirror_ds) && 341 mirror_ds != ERR_PTR(-ENODEV)) 342 nfs4_put_deviceid_node(node); 343 } 344 345 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 346 goto outerr; 347 348 return true; 349 outerr: 350 return false; 351 } 352 353 /** 354 * nfs4_ff_layout_prepare_ds - prepare a DS connection for an RPC call 355 * @lseg: the layout segment we're operating on 356 * @mirror: layout mirror describing the DS to use 357 * @dss_id: DS stripe id to select stripe to use 358 * @fail_return: return layout on connect failure? 359 * 360 * Try to prepare a DS connection to accept an RPC call. This involves 361 * selecting a mirror to use and connecting the client to it if it's not 362 * already connected. 363 * 364 * Since we only need a single functioning mirror to satisfy a read, we don't 365 * want to return the layout if there is one. For writes though, any down 366 * mirror should result in a LAYOUTRETURN. @fail_return is how we distinguish 367 * between the two cases. 368 * 369 * Returns a pointer to a connected DS object on success or NULL on failure. 370 */ 371 struct nfs4_pnfs_ds * 372 nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, 373 struct nfs4_ff_layout_mirror *mirror, 374 u32 dss_id, 375 bool fail_return) 376 { 377 struct nfs4_pnfs_ds *ds; 378 struct inode *ino = lseg->pls_layout->plh_inode; 379 struct nfs_server *s = NFS_SERVER(ino); 380 unsigned int max_payload; 381 int status = -EAGAIN; 382 383 if (!ff_layout_init_mirror_ds(lseg->pls_layout, mirror, dss_id)) 384 goto noconnect; 385 386 ds = mirror->dss[dss_id].mirror_ds->ds; 387 if (READ_ONCE(ds->ds_clp)) 388 goto out; 389 /* matching smp_wmb() in _nfs4_pnfs_v3/4_ds_connect */ 390 smp_rmb(); 391 392 /* FIXME: For now we assume the server sent only one version of NFS 393 * to use for the DS. 394 */ 395 status = nfs4_pnfs_ds_connect(s, ds, &mirror->dss[dss_id].mirror_ds->id_node, 396 dataserver_timeo, dataserver_retrans, 397 mirror->dss[dss_id].mirror_ds->ds_versions[0].version, 398 mirror->dss[dss_id].mirror_ds->ds_versions[0].minor_version); 399 400 /* connect success, check rsize/wsize limit */ 401 if (!status) { 402 /* 403 * ds_clp is put in destroy_ds(). 404 * keep ds_clp even if DS is local, so that if local IO cannot 405 * proceed somehow, we can fall back to NFS whenever we want. 406 */ 407 nfs_local_probe_async(ds->ds_clp); 408 max_payload = 409 nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient), 410 NULL); 411 if (mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize > max_payload) 412 mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize = max_payload; 413 if (mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize > max_payload) 414 mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize = max_payload; 415 goto out; 416 } 417 noconnect: 418 ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout), 419 mirror, dss_id, lseg->pls_range.offset, 420 lseg->pls_range.length, NFS4ERR_NXIO, 421 OP_ILLEGAL, GFP_NOIO); 422 ff_layout_send_layouterror(lseg); 423 if (fail_return || !ff_layout_has_available_ds(lseg)) 424 pnfs_error_mark_layout_for_return(ino, lseg); 425 ds = ERR_PTR(status); 426 out: 427 return ds; 428 } 429 430 const struct cred * 431 ff_layout_get_ds_cred(struct nfs4_ff_layout_mirror *mirror, 432 const struct pnfs_layout_range *range, 433 const struct cred *mdscred, 434 u32 dss_id) 435 { 436 const struct cred *cred; 437 438 if (mirror && !mirror->dss[dss_id].mirror_ds->ds_versions[0].tightly_coupled) { 439 cred = ff_layout_get_mirror_cred(mirror, range->iomode, dss_id); 440 if (!cred) 441 cred = get_cred(mdscred); 442 } else { 443 cred = get_cred(mdscred); 444 } 445 return cred; 446 } 447 448 /** 449 * nfs4_ff_find_or_create_ds_client - Find or create a DS rpc client 450 * @mirror: pointer to the mirror 451 * @ds_clp: nfs_client for the DS 452 * @inode: pointer to inode 453 * @dss_id: DS stripe id 454 * 455 * Find or create a DS rpc client with th MDS server rpc client auth flavor 456 * in the nfs_client cl_ds_clients list. 457 */ 458 struct rpc_clnt * 459 nfs4_ff_find_or_create_ds_client(struct nfs4_ff_layout_mirror *mirror, 460 struct nfs_client *ds_clp, struct inode *inode, 461 u32 dss_id) 462 { 463 switch (mirror->dss[dss_id].mirror_ds->ds_versions[0].version) { 464 case 3: 465 /* For NFSv3 DS, flavor is set when creating DS connections */ 466 return ds_clp->cl_rpcclient; 467 case 4: 468 return nfs4_find_or_create_ds_client(ds_clp, inode); 469 default: 470 BUG(); 471 } 472 } 473 474 void ff_layout_free_ds_ioerr(struct list_head *head) 475 { 476 struct nfs4_ff_layout_ds_err *err; 477 478 while (!list_empty(head)) { 479 err = list_first_entry(head, 480 struct nfs4_ff_layout_ds_err, 481 list); 482 list_del(&err->list); 483 kfree(err); 484 } 485 } 486 487 /* called with inode i_lock held */ 488 int ff_layout_encode_ds_ioerr(struct xdr_stream *xdr, const struct list_head *head) 489 { 490 struct nfs4_ff_layout_ds_err *err; 491 __be32 *p; 492 493 list_for_each_entry(err, head, list) { 494 /* offset(8) + length(8) + stateid(NFS4_STATEID_SIZE) 495 * + array length + deviceid(NFS4_DEVICEID4_SIZE) 496 * + status(4) + opnum(4) 497 */ 498 p = xdr_reserve_space(xdr, 499 28 + NFS4_STATEID_SIZE + NFS4_DEVICEID4_SIZE); 500 if (unlikely(!p)) 501 return -ENOBUFS; 502 p = xdr_encode_hyper(p, err->offset); 503 p = xdr_encode_hyper(p, err->length); 504 p = xdr_encode_opaque_fixed(p, &err->stateid, 505 NFS4_STATEID_SIZE); 506 /* Encode 1 error */ 507 *p++ = cpu_to_be32(1); 508 p = xdr_encode_opaque_fixed(p, &err->deviceid, 509 NFS4_DEVICEID4_SIZE); 510 *p++ = cpu_to_be32(err->status); 511 *p++ = cpu_to_be32(err->opnum); 512 dprintk("%s: offset %llu length %llu status %d op %d\n", 513 __func__, err->offset, err->length, err->status, 514 err->opnum); 515 } 516 517 return 0; 518 } 519 520 static 521 unsigned int do_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, 522 const struct pnfs_layout_range *range, 523 struct list_head *head, 524 unsigned int maxnum) 525 { 526 struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo); 527 struct inode *inode = lo->plh_inode; 528 struct nfs4_ff_layout_ds_err *err, *n; 529 unsigned int ret = 0; 530 531 spin_lock(&inode->i_lock); 532 list_for_each_entry_safe(err, n, &flo->error_list, list) { 533 if (!pnfs_is_range_intersecting(err->offset, 534 pnfs_end_offset(err->offset, err->length), 535 range->offset, 536 pnfs_end_offset(range->offset, range->length))) 537 continue; 538 if (!maxnum) 539 break; 540 list_move(&err->list, head); 541 maxnum--; 542 ret++; 543 } 544 spin_unlock(&inode->i_lock); 545 return ret; 546 } 547 548 unsigned int ff_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, 549 const struct pnfs_layout_range *range, 550 struct list_head *head, 551 unsigned int maxnum) 552 { 553 unsigned int ret; 554 555 ret = do_layout_fetch_ds_ioerr(lo, range, head, maxnum); 556 /* If we're over the max, discard all remaining entries */ 557 if (ret == maxnum) { 558 LIST_HEAD(discard); 559 do_layout_fetch_ds_ioerr(lo, range, &discard, -1); 560 ff_layout_free_ds_ioerr(&discard); 561 } 562 return ret; 563 } 564 565 static bool ff_read_layout_has_available_ds(struct pnfs_layout_segment *lseg) 566 { 567 struct nfs4_ff_layout_mirror *mirror; 568 struct nfs4_deviceid_node *devid; 569 u32 idx, dss_id; 570 571 for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { 572 mirror = FF_LAYOUT_COMP(lseg, idx); 573 if (!mirror) 574 continue; 575 for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) { 576 if (!mirror->dss[dss_id].mirror_ds) 577 return true; 578 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 579 continue; 580 devid = &mirror->dss[dss_id].mirror_ds->id_node; 581 if (!nfs4_test_deviceid_unavailable(devid)) 582 return true; 583 } 584 } 585 586 return false; 587 } 588 589 static bool ff_rw_layout_has_available_ds(struct pnfs_layout_segment *lseg) 590 { 591 struct nfs4_ff_layout_mirror *mirror; 592 struct nfs4_deviceid_node *devid; 593 u32 idx, dss_id; 594 595 for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { 596 mirror = FF_LAYOUT_COMP(lseg, idx); 597 if (!mirror) 598 return false; 599 for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) { 600 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 601 return false; 602 if (!mirror->dss[dss_id].mirror_ds) 603 continue; 604 devid = &mirror->dss[dss_id].mirror_ds->id_node; 605 if (nfs4_test_deviceid_unavailable(devid)) 606 return false; 607 } 608 } 609 610 return FF_LAYOUT_MIRROR_COUNT(lseg) != 0; 611 } 612 613 static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg) 614 { 615 if (lseg->pls_range.iomode == IOMODE_READ) 616 return ff_read_layout_has_available_ds(lseg); 617 /* Note: RW layout needs all mirrors available */ 618 return ff_rw_layout_has_available_ds(lseg); 619 } 620 621 bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg) 622 { 623 return ff_layout_no_fallback_to_mds(lseg) || 624 ff_layout_has_available_ds(lseg); 625 } 626 627 bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg) 628 { 629 return lseg->pls_range.iomode == IOMODE_RW && 630 ff_layout_no_read_on_rw(lseg); 631 } 632 633 module_param(dataserver_retrans, uint, 0644); 634 MODULE_PARM_DESC(dataserver_retrans, "The number of times the NFSv4.1 client " 635 "retries a request before it attempts further " 636 " recovery action."); 637 module_param(dataserver_timeo, uint, 0644); 638 MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the " 639 "NFSv4.1 client waits for a response from a " 640 " data server before it retries an NFS request."); 641