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); 100 101 if (version_count == 0) { 102 ret = -EINVAL; 103 goto out_err_drain_dsaddrs; 104 } 105 dprintk("%s: version count %d\n", __func__, version_count); 106 107 ds_versions = kzalloc_objs(struct nfs4_ff_ds_version, version_count, 108 gfp_flags); 109 if (!ds_versions) 110 goto out_err_drain_dsaddrs; 111 112 for (i = 0; i < version_count; i++) { 113 /* 20 = version(4) + minor_version(4) + rsize(4) + wsize(4) + 114 * tightly_coupled(4) */ 115 p = xdr_inline_decode(&stream, 20); 116 if (unlikely(!p)) 117 goto out_err_drain_dsaddrs; 118 ds_versions[i].version = be32_to_cpup(p++); 119 ds_versions[i].minor_version = be32_to_cpup(p++); 120 ds_versions[i].rsize = nfs_io_size(be32_to_cpup(p++), 121 server->nfs_client->cl_proto); 122 ds_versions[i].wsize = nfs_io_size(be32_to_cpup(p++), 123 server->nfs_client->cl_proto); 124 ds_versions[i].tightly_coupled = be32_to_cpup(p); 125 126 if (ds_versions[i].rsize > NFS_MAX_FILE_IO_SIZE) 127 ds_versions[i].rsize = NFS_MAX_FILE_IO_SIZE; 128 if (ds_versions[i].wsize > NFS_MAX_FILE_IO_SIZE) 129 ds_versions[i].wsize = NFS_MAX_FILE_IO_SIZE; 130 131 /* 132 * check for valid major/minor combination. 133 * currently we support dataserver which talk: 134 * v3, v4.0, v4.1, v4.2 135 */ 136 if (!((ds_versions[i].version == 3 && ds_versions[i].minor_version == 0) || 137 (ds_versions[i].version == 4 && ds_versions[i].minor_version < 3))) { 138 dprintk("%s: [%d] unsupported ds version %d-%d\n", __func__, 139 i, ds_versions[i].version, 140 ds_versions[i].minor_version); 141 ret = -EPROTONOSUPPORT; 142 goto out_err_drain_dsaddrs; 143 } 144 145 dprintk("%s: [%d] vers %u minor_ver %u rsize %u wsize %u coupled %d\n", 146 __func__, i, ds_versions[i].version, 147 ds_versions[i].minor_version, 148 ds_versions[i].rsize, 149 ds_versions[i].wsize, 150 ds_versions[i].tightly_coupled); 151 } 152 153 new_ds->ds_versions = ds_versions; 154 new_ds->ds_versions_cnt = version_count; 155 156 new_ds->ds = nfs4_pnfs_ds_add(net, &dsaddrs, ds_versions[0].version, 157 gfp_flags); 158 if (!new_ds->ds) 159 goto out_err_drain_dsaddrs; 160 161 /* If DS was already in cache, free ds addrs */ 162 while (!list_empty(&dsaddrs)) { 163 da = list_first_entry(&dsaddrs, 164 struct nfs4_pnfs_ds_addr, 165 da_node); 166 list_del_init(&da->da_node); 167 kfree(da->da_remotestr); 168 kfree(da); 169 } 170 171 folio_put(scratch); 172 return new_ds; 173 174 out_err_drain_dsaddrs: 175 while (!list_empty(&dsaddrs)) { 176 da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr, 177 da_node); 178 list_del_init(&da->da_node); 179 kfree(da->da_remotestr); 180 kfree(da); 181 } 182 183 kfree(ds_versions); 184 out_scratch: 185 folio_put(scratch); 186 out_err: 187 kfree(new_ds); 188 189 dprintk("%s ERROR: returning %d\n", __func__, ret); 190 return NULL; 191 } 192 193 static void extend_ds_error(struct nfs4_ff_layout_ds_err *err, 194 u64 offset, u64 length) 195 { 196 u64 end; 197 198 end = max_t(u64, pnfs_end_offset(err->offset, err->length), 199 pnfs_end_offset(offset, length)); 200 err->offset = min_t(u64, err->offset, offset); 201 err->length = end - err->offset; 202 } 203 204 static int 205 ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1, 206 const struct nfs4_ff_layout_ds_err *e2) 207 { 208 int ret; 209 210 if (e1->opnum != e2->opnum) 211 return e1->opnum < e2->opnum ? -1 : 1; 212 if (e1->status != e2->status) 213 return e1->status < e2->status ? -1 : 1; 214 ret = memcmp(e1->stateid.data, e2->stateid.data, 215 sizeof(e1->stateid.data)); 216 if (ret != 0) 217 return ret; 218 ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid)); 219 if (ret != 0) 220 return ret; 221 if (pnfs_end_offset(e1->offset, e1->length) < e2->offset) 222 return -1; 223 if (e1->offset > pnfs_end_offset(e2->offset, e2->length)) 224 return 1; 225 /* If ranges overlap or are contiguous, they are the same */ 226 return 0; 227 } 228 229 static void 230 ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo, 231 struct nfs4_ff_layout_ds_err *dserr) 232 { 233 struct nfs4_ff_layout_ds_err *err, *tmp; 234 struct list_head *head = &flo->error_list; 235 int match; 236 237 /* Do insertion sort w/ merges */ 238 list_for_each_entry_safe(err, tmp, &flo->error_list, list) { 239 match = ff_ds_error_match(err, dserr); 240 if (match < 0) 241 continue; 242 if (match > 0) { 243 /* Add entry "dserr" _before_ entry "err" */ 244 head = &err->list; 245 break; 246 } 247 /* Entries match, so merge "err" into "dserr" */ 248 extend_ds_error(dserr, err->offset, err->length); 249 list_replace(&err->list, &dserr->list); 250 kfree(err); 251 return; 252 } 253 254 list_add_tail(&dserr->list, head); 255 } 256 257 int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo, 258 struct nfs4_ff_layout_mirror *mirror, 259 u32 dss_id, u64 offset, u64 length, int status, 260 enum nfs_opnum4 opnum, gfp_t gfp_flags) 261 { 262 struct nfs4_ff_layout_ds_err *dserr; 263 264 if (status == 0) 265 return 0; 266 267 if (IS_ERR_OR_NULL(mirror->dss[dss_id].mirror_ds)) 268 return -EINVAL; 269 270 dserr = kmalloc_obj(*dserr, gfp_flags); 271 if (!dserr) 272 return -ENOMEM; 273 274 INIT_LIST_HEAD(&dserr->list); 275 dserr->offset = offset; 276 dserr->length = length; 277 dserr->status = status; 278 dserr->opnum = opnum; 279 nfs4_stateid_copy(&dserr->stateid, &mirror->dss[dss_id].stateid); 280 memcpy(&dserr->deviceid, &mirror->dss[dss_id].mirror_ds->id_node.deviceid, 281 NFS4_DEVICEID4_SIZE); 282 283 spin_lock(&flo->generic_hdr.plh_inode->i_lock); 284 ff_layout_add_ds_error_locked(flo, dserr); 285 spin_unlock(&flo->generic_hdr.plh_inode->i_lock); 286 return 0; 287 } 288 289 static const struct cred * 290 ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode, u32 dss_id) 291 { 292 const struct cred *cred, __rcu **pcred; 293 294 if (iomode == IOMODE_READ) 295 pcred = &mirror->dss[dss_id].ro_cred; 296 else 297 pcred = &mirror->dss[dss_id].rw_cred; 298 299 rcu_read_lock(); 300 do { 301 cred = rcu_dereference(*pcred); 302 if (!cred) 303 break; 304 305 cred = get_cred_rcu(cred); 306 } while(!cred); 307 rcu_read_unlock(); 308 return cred; 309 } 310 311 struct nfs_fh * 312 nfs4_ff_layout_select_ds_fh(struct nfs4_ff_layout_mirror *mirror, u32 dss_id) 313 { 314 /* FIXME: For now assume there is only 1 version available for the DS */ 315 return &mirror->dss[dss_id].fh_versions[0]; 316 } 317 318 void 319 nfs4_ff_layout_select_ds_stateid(const struct nfs4_ff_layout_mirror *mirror, 320 u32 dss_id, 321 nfs4_stateid *stateid) 322 { 323 if (nfs4_ff_layout_ds_version(mirror, dss_id) == 4) 324 nfs4_stateid_copy(stateid, &mirror->dss[dss_id].stateid); 325 } 326 327 static bool 328 ff_layout_init_mirror_ds(struct pnfs_layout_hdr *lo, 329 struct nfs4_ff_layout_mirror *mirror, 330 u32 dss_id) 331 { 332 if (mirror == NULL) 333 goto outerr; 334 if (mirror->dss[dss_id].mirror_ds == NULL) { 335 struct nfs4_deviceid_node *node; 336 struct nfs4_ff_layout_ds *mirror_ds = ERR_PTR(-ENODEV); 337 338 node = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), 339 &mirror->dss[dss_id].devid, lo->plh_lc_cred, 340 GFP_KERNEL); 341 if (node) 342 mirror_ds = FF_LAYOUT_MIRROR_DS(node); 343 344 /* check for race with another call to this function */ 345 if (cmpxchg(&mirror->dss[dss_id].mirror_ds, NULL, mirror_ds) && 346 mirror_ds != ERR_PTR(-ENODEV)) 347 nfs4_put_deviceid_node(node); 348 } 349 350 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 351 goto outerr; 352 353 return true; 354 outerr: 355 return false; 356 } 357 358 /** 359 * nfs4_ff_layout_prepare_ds - prepare a DS connection for an RPC call 360 * @lseg: the layout segment we're operating on 361 * @mirror: layout mirror describing the DS to use 362 * @dss_id: DS stripe id to select stripe to use 363 * @fail_return: return layout on connect failure? 364 * 365 * Try to prepare a DS connection to accept an RPC call. This involves 366 * selecting a mirror to use and connecting the client to it if it's not 367 * already connected. 368 * 369 * Since we only need a single functioning mirror to satisfy a read, we don't 370 * want to return the layout if there is one. For writes though, any down 371 * mirror should result in a LAYOUTRETURN. @fail_return is how we distinguish 372 * between the two cases. 373 * 374 * Returns a pointer to a connected DS object on success or NULL on failure. 375 */ 376 struct nfs4_pnfs_ds * 377 nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, 378 struct nfs4_ff_layout_mirror *mirror, 379 u32 dss_id, 380 bool fail_return) 381 { 382 struct nfs4_pnfs_ds *ds; 383 struct inode *ino = lseg->pls_layout->plh_inode; 384 struct nfs_server *s = NFS_SERVER(ino); 385 unsigned int max_payload; 386 int status = -EAGAIN; 387 388 if (!ff_layout_init_mirror_ds(lseg->pls_layout, mirror, dss_id)) 389 goto noconnect; 390 391 ds = mirror->dss[dss_id].mirror_ds->ds; 392 if (READ_ONCE(ds->ds_clp)) 393 goto out; 394 /* matching smp_wmb() in _nfs4_pnfs_v3/4_ds_connect */ 395 smp_rmb(); 396 397 /* FIXME: For now we assume the server sent only one version of NFS 398 * to use for the DS. 399 */ 400 status = nfs4_pnfs_ds_connect(s, ds, &mirror->dss[dss_id].mirror_ds->id_node, 401 dataserver_timeo, dataserver_retrans, 402 mirror->dss[dss_id].mirror_ds->ds_versions[0].version, 403 mirror->dss[dss_id].mirror_ds->ds_versions[0].minor_version, 404 mirror->dss[dss_id].mirror_ds->ds_versions[0].tightly_coupled); 405 406 /* connect success, check rsize/wsize limit */ 407 if (!status) { 408 /* 409 * ds_clp is put in destroy_ds(). 410 * keep ds_clp even if DS is local, so that if local IO cannot 411 * proceed somehow, we can fall back to NFS whenever we want. 412 */ 413 nfs_local_probe_async(ds->ds_clp); 414 max_payload = 415 nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient), 416 NULL); 417 if (mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize > max_payload) 418 mirror->dss[dss_id].mirror_ds->ds_versions[0].rsize = max_payload; 419 if (mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize > max_payload) 420 mirror->dss[dss_id].mirror_ds->ds_versions[0].wsize = max_payload; 421 goto out; 422 } 423 noconnect: 424 ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout), 425 mirror, dss_id, lseg->pls_range.offset, 426 lseg->pls_range.length, NFS4ERR_NXIO, 427 OP_ILLEGAL, GFP_NOIO); 428 ff_layout_send_layouterror(lseg); 429 if (fail_return || !ff_layout_has_available_ds(lseg)) 430 pnfs_error_mark_layout_for_return(ino, lseg); 431 ds = ERR_PTR(status); 432 out: 433 return ds; 434 } 435 436 const struct cred * 437 ff_layout_get_ds_cred(struct nfs4_ff_layout_mirror *mirror, 438 const struct pnfs_layout_range *range, 439 const struct cred *mdscred, 440 u32 dss_id) 441 { 442 const struct cred *cred; 443 444 if (mirror && !mirror->dss[dss_id].mirror_ds->ds_versions[0].tightly_coupled) { 445 cred = ff_layout_get_mirror_cred(mirror, range->iomode, dss_id); 446 if (!cred) 447 cred = get_cred(mdscred); 448 } else { 449 cred = get_cred(mdscred); 450 } 451 return cred; 452 } 453 454 /** 455 * nfs4_ff_find_or_create_ds_client - Find or create a DS rpc client 456 * @mirror: pointer to the mirror 457 * @ds_clp: nfs_client for the DS 458 * @inode: pointer to inode 459 * @dss_id: DS stripe id 460 * 461 * Find or create a DS rpc client with th MDS server rpc client auth flavor 462 * in the nfs_client cl_ds_clients list. 463 */ 464 struct rpc_clnt * 465 nfs4_ff_find_or_create_ds_client(struct nfs4_ff_layout_mirror *mirror, 466 struct nfs_client *ds_clp, struct inode *inode, 467 u32 dss_id) 468 { 469 switch (mirror->dss[dss_id].mirror_ds->ds_versions[0].version) { 470 case 3: 471 /* For NFSv3 DS, flavor is set when creating DS connections */ 472 return ds_clp->cl_rpcclient; 473 case 4: 474 return nfs4_find_or_create_ds_client(ds_clp, inode); 475 default: 476 BUG(); 477 } 478 } 479 480 void ff_layout_free_ds_ioerr(struct list_head *head) 481 { 482 struct nfs4_ff_layout_ds_err *err; 483 484 while (!list_empty(head)) { 485 err = list_first_entry(head, 486 struct nfs4_ff_layout_ds_err, 487 list); 488 list_del(&err->list); 489 kfree(err); 490 } 491 } 492 493 /* called with inode i_lock held */ 494 int ff_layout_encode_ds_ioerr(struct xdr_stream *xdr, const struct list_head *head) 495 { 496 struct nfs4_ff_layout_ds_err *err; 497 __be32 *p; 498 499 list_for_each_entry(err, head, list) { 500 /* offset(8) + length(8) + stateid(NFS4_STATEID_SIZE) 501 * + array length + deviceid(NFS4_DEVICEID4_SIZE) 502 * + status(4) + opnum(4) 503 */ 504 p = xdr_reserve_space(xdr, 505 28 + NFS4_STATEID_SIZE + NFS4_DEVICEID4_SIZE); 506 if (unlikely(!p)) 507 return -ENOBUFS; 508 p = xdr_encode_hyper(p, err->offset); 509 p = xdr_encode_hyper(p, err->length); 510 p = xdr_encode_opaque_fixed(p, &err->stateid, 511 NFS4_STATEID_SIZE); 512 /* Encode 1 error */ 513 *p++ = cpu_to_be32(1); 514 p = xdr_encode_opaque_fixed(p, &err->deviceid, 515 NFS4_DEVICEID4_SIZE); 516 *p++ = cpu_to_be32(err->status); 517 *p++ = cpu_to_be32(err->opnum); 518 dprintk("%s: offset %llu length %llu status %d op %d\n", 519 __func__, err->offset, err->length, err->status, 520 err->opnum); 521 } 522 523 return 0; 524 } 525 526 static 527 unsigned int do_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, 528 const struct pnfs_layout_range *range, 529 struct list_head *head, 530 unsigned int maxnum) 531 { 532 struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo); 533 struct inode *inode = lo->plh_inode; 534 struct nfs4_ff_layout_ds_err *err, *n; 535 unsigned int ret = 0; 536 537 spin_lock(&inode->i_lock); 538 list_for_each_entry_safe(err, n, &flo->error_list, list) { 539 if (!pnfs_is_range_intersecting(err->offset, 540 pnfs_end_offset(err->offset, err->length), 541 range->offset, 542 pnfs_end_offset(range->offset, range->length))) 543 continue; 544 if (!maxnum) 545 break; 546 list_move(&err->list, head); 547 maxnum--; 548 ret++; 549 } 550 spin_unlock(&inode->i_lock); 551 return ret; 552 } 553 554 unsigned int ff_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo, 555 const struct pnfs_layout_range *range, 556 struct list_head *head, 557 unsigned int maxnum) 558 { 559 unsigned int ret; 560 561 ret = do_layout_fetch_ds_ioerr(lo, range, head, maxnum); 562 /* If we're over the max, discard all remaining entries */ 563 if (ret == maxnum) { 564 LIST_HEAD(discard); 565 do_layout_fetch_ds_ioerr(lo, range, &discard, -1); 566 ff_layout_free_ds_ioerr(&discard); 567 } 568 return ret; 569 } 570 571 static bool ff_read_layout_has_available_ds(struct pnfs_layout_segment *lseg) 572 { 573 struct nfs4_ff_layout_mirror *mirror; 574 struct nfs4_deviceid_node *devid; 575 u32 idx, dss_id; 576 577 for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { 578 mirror = FF_LAYOUT_COMP(lseg, idx); 579 if (!mirror) 580 continue; 581 for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) { 582 if (!mirror->dss[dss_id].mirror_ds) 583 return true; 584 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 585 continue; 586 devid = &mirror->dss[dss_id].mirror_ds->id_node; 587 if (!nfs4_test_deviceid_unavailable(devid)) 588 return true; 589 } 590 } 591 592 return false; 593 } 594 595 static bool ff_rw_layout_has_available_ds(struct pnfs_layout_segment *lseg) 596 { 597 struct nfs4_ff_layout_mirror *mirror; 598 struct nfs4_deviceid_node *devid; 599 u32 idx, dss_id; 600 601 for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) { 602 mirror = FF_LAYOUT_COMP(lseg, idx); 603 if (!mirror) 604 return false; 605 for (dss_id = 0; dss_id < mirror->dss_count; dss_id++) { 606 if (IS_ERR(mirror->dss[dss_id].mirror_ds)) 607 return false; 608 if (!mirror->dss[dss_id].mirror_ds) 609 continue; 610 devid = &mirror->dss[dss_id].mirror_ds->id_node; 611 if (nfs4_test_deviceid_unavailable(devid)) 612 return false; 613 } 614 } 615 616 return FF_LAYOUT_MIRROR_COUNT(lseg) != 0; 617 } 618 619 static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg) 620 { 621 if (lseg->pls_range.iomode == IOMODE_READ) 622 return ff_read_layout_has_available_ds(lseg); 623 /* Note: RW layout needs all mirrors available */ 624 return ff_rw_layout_has_available_ds(lseg); 625 } 626 627 bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg) 628 { 629 return ff_layout_no_fallback_to_mds(lseg) || 630 ff_layout_has_available_ds(lseg); 631 } 632 633 bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg) 634 { 635 return lseg->pls_range.iomode == IOMODE_RW && 636 ff_layout_no_read_on_rw(lseg); 637 } 638 639 module_param(dataserver_retrans, uint, 0644); 640 MODULE_PARM_DESC(dataserver_retrans, "The number of times the NFSv4.1 client " 641 "retries a request before it attempts further " 642 " recovery action."); 643 module_param(dataserver_timeo, uint, 0644); 644 MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the " 645 "NFSv4.1 client waits for a response from a " 646 " data server before it retries an NFS request."); 647