fs/nfs/flexfilelayout/flexfilelayoutdev.c

   1 /*
   2  * Device operations for the pnfs nfs4 file layout driver.
   3  *
   4  * Copyright (c) 2014, Primary Data, Inc. All rights reserved.
   5  *
   6  * Tao Peng <bergwolf@primarydata.com>
   7  */
   8
   9 #include <linux/nfs_fs.h>
  10 #include <linux/vmalloc.h>
  11 #include <linux/module.h>
  12 #include <linux/sunrpc/addr.h>
  13
  14 #include "../internal.h"
  15 #include "../nfs4session.h"
  16 #include "flexfilelayout.h"
  17
  18 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  19
  20 static unsigned int dataserver_timeo = NFS_DEF_TCP_RETRANS;
  21 static unsigned int dataserver_retrans;
  22
  23 static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg);
  24
  25 void nfs4_ff_layout_put_deviceid(struct nfs4_ff_layout_ds *mirror_ds)
  26 {
  27         if (!IS_ERR_OR_NULL(mirror_ds))
  28                 nfs4_put_deviceid_node(&mirror_ds->id_node);
  29 }
  30
  31 void nfs4_ff_layout_free_deviceid(struct nfs4_ff_layout_ds *mirror_ds)
  32 {
  33         nfs4_print_deviceid(&mirror_ds->id_node.deviceid);
  34         nfs4_pnfs_ds_put(mirror_ds->ds);
  35         kfree_rcu(mirror_ds, id_node.rcu);
  36 }
  37
  38 /* Decode opaque device data and construct new_ds using it */
  39 struct nfs4_ff_layout_ds *
  40 nfs4_ff_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
  41                             gfp_t gfp_flags)
  42 {
  43         struct xdr_stream stream;
  44         struct xdr_buf buf;
  45         struct page *scratch;
  46         struct list_head dsaddrs;
  47         struct nfs4_pnfs_ds_addr *da;
  48         struct nfs4_ff_layout_ds *new_ds = NULL;
  49         struct nfs4_ff_ds_version *ds_versions = NULL;
  50         u32 mp_count;
  51         u32 version_count;
  52         __be32 *p;
  53         int i, ret = -ENOMEM;
  54
  55         /* set up xdr stream */
  56         scratch = alloc_page(gfp_flags);
  57         if (!scratch)
  58                 goto out_err;
  59
  60         new_ds = kzalloc(sizeof(struct nfs4_ff_layout_ds), gfp_flags);
  61         if (!new_ds)
  62                 goto out_scratch;
  63
  64         nfs4_init_deviceid_node(&new_ds->id_node,
  65                                 server,
  66                                 &pdev->dev_id);
  67         INIT_LIST_HEAD(&dsaddrs);
  68
  69         xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen);
  70         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
  71
  72         /* multipath count */
  73         p = xdr_inline_decode(&stream, 4);
  74         if (unlikely(!p))
  75                 goto out_err_drain_dsaddrs;
  76         mp_count = be32_to_cpup(p);
  77         dprintk("%s: multipath ds count %d\n", __func__, mp_count);
  78
  79         for (i = 0; i < mp_count; i++) {
  80                 /* multipath ds */
  81                 da = nfs4_decode_mp_ds_addr(server->nfs_client->cl_net,
  82                                             &stream, gfp_flags);
  83                 if (da)
  84                         list_add_tail(&da->da_node, &dsaddrs);
  85         }
  86         if (list_empty(&dsaddrs)) {
  87                 dprintk("%s: no suitable DS addresses found\n",
  88                         __func__);
  89                 ret = -ENOMEDIUM;
  90                 goto out_err_drain_dsaddrs;
  91         }
  92
  93         /* version count */
  94         p = xdr_inline_decode(&stream, 4);
  95         if (unlikely(!p))
  96                 goto out_err_drain_dsaddrs;
  97         version_count = be32_to_cpup(p);
  98         dprintk("%s: version count %d\n", __func__, version_count);
  99
 100         ds_versions = kzalloc(version_count * sizeof(struct nfs4_ff_ds_version),
 101                               gfp_flags);
 102         if (!ds_versions)
 103                 goto out_scratch;
 104
 105         for (i = 0; i < version_count; i++) {
 106                 /* 20 = version(4) + minor_version(4) + rsize(4) + wsize(4) +
 107                  * tightly_coupled(4) */
 108                 p = xdr_inline_decode(&stream, 20);
 109                 if (unlikely(!p))
 110                         goto out_err_drain_dsaddrs;
 111                 ds_versions[i].version = be32_to_cpup(p++);
 112                 ds_versions[i].minor_version = be32_to_cpup(p++);
 113                 ds_versions[i].rsize = nfs_block_size(be32_to_cpup(p++), NULL);
 114                 ds_versions[i].wsize = nfs_block_size(be32_to_cpup(p++), NULL);
 115                 ds_versions[i].tightly_coupled = be32_to_cpup(p);
 116
 117                 if (ds_versions[i].rsize > NFS_MAX_FILE_IO_SIZE)
 118                         ds_versions[i].rsize = NFS_MAX_FILE_IO_SIZE;
 119                 if (ds_versions[i].wsize > NFS_MAX_FILE_IO_SIZE)
 120                         ds_versions[i].wsize = NFS_MAX_FILE_IO_SIZE;
 121
 122                 /*
 123                  * check for valid major/minor combination.
 124                  * currently we support dataserver which talk:
 125                  *   v3, v4.0, v4.1, v4.2
 126                  */
 127                 if (!((ds_versions[i].version == 3 && ds_versions[i].minor_version == 0) ||
 128                         (ds_versions[i].version == 4 && ds_versions[i].minor_version < 3))) {
 129                         dprintk("%s: [%d] unsupported ds version %d-%d\n", __func__,
 130                                 i, ds_versions[i].version,
 131                                 ds_versions[i].minor_version);
 132                         ret = -EPROTONOSUPPORT;
 133                         goto out_err_drain_dsaddrs;
 134                 }
 135
 136                 dprintk("%s: [%d] vers %u minor_ver %u rsize %u wsize %u coupled %d\n",
 137                         __func__, i, ds_versions[i].version,
 138                         ds_versions[i].minor_version,
 139                         ds_versions[i].rsize,
 140                         ds_versions[i].wsize,
 141                         ds_versions[i].tightly_coupled);
 142         }
 143
 144         new_ds->ds_versions = ds_versions;
 145         new_ds->ds_versions_cnt = version_count;
 146
 147         new_ds->ds = nfs4_pnfs_ds_add(&dsaddrs, gfp_flags);
 148         if (!new_ds->ds)
 149                 goto out_err_drain_dsaddrs;
 150
 151         /* If DS was already in cache, free ds addrs */
 152         while (!list_empty(&dsaddrs)) {
 153                 da = list_first_entry(&dsaddrs,
 154                                       struct nfs4_pnfs_ds_addr,
 155                                       da_node);
 156                 list_del_init(&da->da_node);
 157                 kfree(da->da_remotestr);
 158                 kfree(da);
 159         }
 160
 161         __free_page(scratch);
 162         return new_ds;
 163
 164 out_err_drain_dsaddrs:
 165         while (!list_empty(&dsaddrs)) {
 166                 da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr,
 167                                       da_node);
 168                 list_del_init(&da->da_node);
 169                 kfree(da->da_remotestr);
 170                 kfree(da);
 171         }
 172
 173         kfree(ds_versions);
 174 out_scratch:
 175         __free_page(scratch);
 176 out_err:
 177         kfree(new_ds);
 178
 179         dprintk("%s ERROR: returning %d\n", __func__, ret);
 180         return NULL;
 181 }
 182
 183 static void ff_layout_mark_devid_invalid(struct pnfs_layout_segment *lseg,
 184                 struct nfs4_deviceid_node *devid)
 185 {
 186         nfs4_delete_deviceid(devid->ld, devid->nfs_client, &devid->deviceid);
 187         if (!ff_layout_has_available_ds(lseg))
 188                 pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode,
 189                                 lseg);
 190 }
 191
 192 static bool ff_layout_mirror_valid(struct pnfs_layout_segment *lseg,
 193                                    struct nfs4_ff_layout_mirror *mirror,
 194                                    bool create)
 195 {
 196         if (mirror == NULL || IS_ERR(mirror->mirror_ds))
 197                 goto outerr;
 198         if (mirror->mirror_ds == NULL) {
 199                 if (create) {
 200                         struct nfs4_deviceid_node *node;
 201                         struct pnfs_layout_hdr *lh = lseg->pls_layout;
 202                         struct nfs4_ff_layout_ds *mirror_ds = ERR_PTR(-ENODEV);
 203
 204                         node = nfs4_find_get_deviceid(NFS_SERVER(lh->plh_inode),
 205                                         &mirror->devid, lh->plh_lc_cred,
 206                                         GFP_KERNEL);
 207                         if (node)
 208                                 mirror_ds = FF_LAYOUT_MIRROR_DS(node);
 209
 210                         /* check for race with another call to this function */
 211                         if (cmpxchg(&mirror->mirror_ds, NULL, mirror_ds) &&
 212                             mirror_ds != ERR_PTR(-ENODEV))
 213                                 nfs4_put_deviceid_node(node);
 214                 } else
 215                         goto outerr;
 216         }
 217
 218         if (IS_ERR(mirror->mirror_ds))
 219                 goto outerr;
 220
 221         if (mirror->mirror_ds->ds == NULL) {
 222                 struct nfs4_deviceid_node *devid;
 223                 devid = &mirror->mirror_ds->id_node;
 224                 ff_layout_mark_devid_invalid(lseg, devid);
 225                 return false;
 226         }
 227         return true;
 228 outerr:
 229         pnfs_error_mark_layout_for_return(lseg->pls_layout->plh_inode, lseg);
 230         return false;
 231 }
 232
 233 static void extend_ds_error(struct nfs4_ff_layout_ds_err *err,
 234                             u64 offset, u64 length)
 235 {
 236         u64 end;
 237
 238         end = max_t(u64, pnfs_end_offset(err->offset, err->length),
 239                     pnfs_end_offset(offset, length));
 240         err->offset = min_t(u64, err->offset, offset);
 241         err->length = end - err->offset;
 242 }
 243
 244 static int
 245 ff_ds_error_match(const struct nfs4_ff_layout_ds_err *e1,
 246                 const struct nfs4_ff_layout_ds_err *e2)
 247 {
 248         int ret;
 249
 250         if (e1->opnum != e2->opnum)
 251                 return e1->opnum < e2->opnum ? -1 : 1;
 252         if (e1->status != e2->status)
 253                 return e1->status < e2->status ? -1 : 1;
 254         ret = memcmp(e1->stateid.data, e2->stateid.data,
 255                         sizeof(e1->stateid.data));
 256         if (ret != 0)
 257                 return ret;
 258         ret = memcmp(&e1->deviceid, &e2->deviceid, sizeof(e1->deviceid));
 259         if (ret != 0)
 260                 return ret;
 261         if (pnfs_end_offset(e1->offset, e1->length) < e2->offset)
 262                 return -1;
 263         if (e1->offset > pnfs_end_offset(e2->offset, e2->length))
 264                 return 1;
 265         /* If ranges overlap or are contiguous, they are the same */
 266         return 0;
 267 }
 268
 269 static void
 270 ff_layout_add_ds_error_locked(struct nfs4_flexfile_layout *flo,
 271                               struct nfs4_ff_layout_ds_err *dserr)
 272 {
 273         struct nfs4_ff_layout_ds_err *err, *tmp;
 274         struct list_head *head = &flo->error_list;
 275         int match;
 276
 277         /* Do insertion sort w/ merges */
 278         list_for_each_entry_safe(err, tmp, &flo->error_list, list) {
 279                 match = ff_ds_error_match(err, dserr);
 280                 if (match < 0)
 281                         continue;
 282                 if (match > 0) {
 283                         /* Add entry "dserr" _before_ entry "err" */
 284                         head = &err->list;
 285                         break;
 286                 }
 287                 /* Entries match, so merge "err" into "dserr" */
 288                 extend_ds_error(dserr, err->offset, err->length);
 289                 list_replace(&err->list, &dserr->list);
 290                 kfree(err);
 291                 return;
 292         }
 293
 294         list_add_tail(&dserr->list, head);
 295 }
 296
 297 int ff_layout_track_ds_error(struct nfs4_flexfile_layout *flo,
 298                              struct nfs4_ff_layout_mirror *mirror, u64 offset,
 299                              u64 length, int status, enum nfs_opnum4 opnum,
 300                              gfp_t gfp_flags)
 301 {
 302         struct nfs4_ff_layout_ds_err *dserr;
 303
 304         if (status == 0)
 305                 return 0;
 306
 307         if (mirror->mirror_ds == NULL)
 308                 return -EINVAL;
 309
 310         dserr = kmalloc(sizeof(*dserr), gfp_flags);
 311         if (!dserr)
 312                 return -ENOMEM;
 313
 314         INIT_LIST_HEAD(&dserr->list);
 315         dserr->offset = offset;
 316         dserr->length = length;
 317         dserr->status = status;
 318         dserr->opnum = opnum;
 319         nfs4_stateid_copy(&dserr->stateid, &mirror->stateid);
 320         memcpy(&dserr->deviceid, &mirror->mirror_ds->id_node.deviceid,
 321                NFS4_DEVICEID4_SIZE);
 322
 323         spin_lock(&flo->generic_hdr.plh_inode->i_lock);
 324         ff_layout_add_ds_error_locked(flo, dserr);
 325         spin_unlock(&flo->generic_hdr.plh_inode->i_lock);
 326
 327         return 0;
 328 }
 329
 330 static struct rpc_cred *
 331 ff_layout_get_mirror_cred(struct nfs4_ff_layout_mirror *mirror, u32 iomode)
 332 {
 333         struct rpc_cred *cred, __rcu **pcred;
 334
 335         if (iomode == IOMODE_READ)
 336                 pcred = &mirror->ro_cred;
 337         else
 338                 pcred = &mirror->rw_cred;
 339
 340         rcu_read_lock();
 341         do {
 342                 cred = rcu_dereference(*pcred);
 343                 if (!cred)
 344                         break;
 345
 346                 cred = get_rpccred_rcu(cred);
 347         } while(!cred);
 348         rcu_read_unlock();
 349         return cred;
 350 }
 351
 352 struct nfs_fh *
 353 nfs4_ff_layout_select_ds_fh(struct pnfs_layout_segment *lseg, u32 mirror_idx)
 354 {
 355         struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, mirror_idx);
 356         struct nfs_fh *fh = NULL;
 357
 358         if (!ff_layout_mirror_valid(lseg, mirror, false)) {
 359                 pr_err_ratelimited("NFS: %s: No data server for mirror offset index %d\n",
 360                         __func__, mirror_idx);
 361                 goto out;
 362         }
 363
 364         /* FIXME: For now assume there is only 1 version available for the DS */
 365         fh = &mirror->fh_versions[0];
 366 out:
 367         return fh;
 368 }
 369
 370 /**
 371  * nfs4_ff_layout_prepare_ds - prepare a DS connection for an RPC call
 372  * @lseg: the layout segment we're operating on
 373  * @ds_idx: index of the DS to use
 374  * @fail_return: return layout on connect failure?
 375  *
 376  * Try to prepare a DS connection to accept an RPC call. This involves
 377  * selecting a mirror to use and connecting the client to it if it's not
 378  * already connected.
 379  *
 380  * Since we only need a single functioning mirror to satisfy a read, we don't
 381  * want to return the layout if there is one. For writes though, any down
 382  * mirror should result in a LAYOUTRETURN. @fail_return is how we distinguish
 383  * between the two cases.
 384  *
 385  * Returns a pointer to a connected DS object on success or NULL on failure.
 386  */
 387 struct nfs4_pnfs_ds *
 388 nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx,
 389                           bool fail_return)
 390 {
 391         struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
 392         struct nfs4_pnfs_ds *ds = NULL;
 393         struct nfs4_deviceid_node *devid;
 394         struct inode *ino = lseg->pls_layout->plh_inode;
 395         struct nfs_server *s = NFS_SERVER(ino);
 396         unsigned int max_payload;
 397         int status;
 398
 399         if (!ff_layout_mirror_valid(lseg, mirror, true)) {
 400                 pr_err_ratelimited("NFS: %s: No data server for offset index %d\n",
 401                         __func__, ds_idx);
 402                 goto out;
 403         }
 404
 405         devid = &mirror->mirror_ds->id_node;
 406         if (ff_layout_test_devid_unavailable(devid))
 407                 goto out_fail;
 408
 409         ds = mirror->mirror_ds->ds;
 410         /* matching smp_wmb() in _nfs4_pnfs_v3/4_ds_connect */
 411         smp_rmb();
 412         if (ds->ds_clp)
 413                 goto out;
 414
 415         /* FIXME: For now we assume the server sent only one version of NFS
 416          * to use for the DS.
 417          */
 418         status = nfs4_pnfs_ds_connect(s, ds, devid, dataserver_timeo,
 419                              dataserver_retrans,
 420                              mirror->mirror_ds->ds_versions[0].version,
 421                              mirror->mirror_ds->ds_versions[0].minor_version);
 422
 423         /* connect success, check rsize/wsize limit */
 424         if (!status) {
 425                 max_payload =
 426                         nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient),
 427                                        NULL);
 428                 if (mirror->mirror_ds->ds_versions[0].rsize > max_payload)
 429                         mirror->mirror_ds->ds_versions[0].rsize = max_payload;
 430                 if (mirror->mirror_ds->ds_versions[0].wsize > max_payload)
 431                         mirror->mirror_ds->ds_versions[0].wsize = max_payload;
 432                 goto out;
 433         }
 434 out_fail:
 435         ff_layout_track_ds_error(FF_LAYOUT_FROM_HDR(lseg->pls_layout),
 436                                  mirror, lseg->pls_range.offset,
 437                                  lseg->pls_range.length, NFS4ERR_NXIO,
 438                                  OP_ILLEGAL, GFP_NOIO);
 439         if (fail_return || !ff_layout_has_available_ds(lseg))
 440                 pnfs_error_mark_layout_for_return(ino, lseg);
 441         ds = NULL;
 442 out:
 443         return ds;
 444 }
 445
 446 struct rpc_cred *
 447 ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg, u32 ds_idx,
 448                       struct rpc_cred *mdscred)
 449 {
 450         struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
 451         struct rpc_cred *cred;
 452
 453         if (mirror) {
 454                 cred = ff_layout_get_mirror_cred(mirror, lseg->pls_range.iomode);
 455                 if (!cred)
 456                         cred = get_rpccred(mdscred);
 457         } else {
 458                 cred = get_rpccred(mdscred);
 459         }
 460         return cred;
 461 }
 462
 463 /**
 464 * Find or create a DS rpc client with th MDS server rpc client auth flavor
 465 * in the nfs_client cl_ds_clients list.
 466 */
 467 struct rpc_clnt *
 468 nfs4_ff_find_or_create_ds_client(struct pnfs_layout_segment *lseg, u32 ds_idx,
 469                                  struct nfs_client *ds_clp, struct inode *inode)
 470 {
 471         struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
 472
 473         switch (mirror->mirror_ds->ds_versions[0].version) {
 474         case 3:
 475                 /* For NFSv3 DS, flavor is set when creating DS connections */
 476                 return ds_clp->cl_rpcclient;
 477         case 4:
 478                 return nfs4_find_or_create_ds_client(ds_clp, inode);
 479         default:
 480                 BUG();
 481         }
 482 }
 483
 484 void ff_layout_free_ds_ioerr(struct list_head *head)
 485 {
 486         struct nfs4_ff_layout_ds_err *err;
 487
 488         while (!list_empty(head)) {
 489                 err = list_first_entry(head,
 490                                 struct nfs4_ff_layout_ds_err,
 491                                 list);
 492                 list_del(&err->list);
 493                 kfree(err);
 494         }
 495 }
 496
 497 /* called with inode i_lock held */
 498 int ff_layout_encode_ds_ioerr(struct xdr_stream *xdr, const struct list_head *head)
 499 {
 500         struct nfs4_ff_layout_ds_err *err;
 501         __be32 *p;
 502
 503         list_for_each_entry(err, head, list) {
 504                 /* offset(8) + length(8) + stateid(NFS4_STATEID_SIZE)
 505                  * + array length + deviceid(NFS4_DEVICEID4_SIZE)
 506                  * + status(4) + opnum(4)
 507                  */
 508                 p = xdr_reserve_space(xdr,
 509                                 28 + NFS4_STATEID_SIZE + NFS4_DEVICEID4_SIZE);
 510                 if (unlikely(!p))
 511                         return -ENOBUFS;
 512                 p = xdr_encode_hyper(p, err->offset);
 513                 p = xdr_encode_hyper(p, err->length);
 514                 p = xdr_encode_opaque_fixed(p, &err->stateid,
 515                                             NFS4_STATEID_SIZE);
 516                 /* Encode 1 error */
 517                 *p++ = cpu_to_be32(1);
 518                 p = xdr_encode_opaque_fixed(p, &err->deviceid,
 519                                             NFS4_DEVICEID4_SIZE);
 520                 *p++ = cpu_to_be32(err->status);
 521                 *p++ = cpu_to_be32(err->opnum);
 522                 dprintk("%s: offset %llu length %llu status %d op %d\n",
 523                         __func__, err->offset, err->length, err->status,
 524                         err->opnum);
 525         }
 526
 527         return 0;
 528 }
 529
 530 static
 531 unsigned int do_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo,
 532                                       const struct pnfs_layout_range *range,
 533                                       struct list_head *head,
 534                                       unsigned int maxnum)
 535 {
 536         struct nfs4_flexfile_layout *flo = FF_LAYOUT_FROM_HDR(lo);
 537         struct inode *inode = lo->plh_inode;
 538         struct nfs4_ff_layout_ds_err *err, *n;
 539         unsigned int ret = 0;
 540
 541         spin_lock(&inode->i_lock);
 542         list_for_each_entry_safe(err, n, &flo->error_list, list) {
 543                 if (!pnfs_is_range_intersecting(err->offset,
 544                                 pnfs_end_offset(err->offset, err->length),
 545                                 range->offset,
 546                                 pnfs_end_offset(range->offset, range->length)))
 547                         continue;
 548                 if (!maxnum)
 549                         break;
 550                 list_move(&err->list, head);
 551                 maxnum--;
 552                 ret++;
 553         }
 554         spin_unlock(&inode->i_lock);
 555         return ret;
 556 }
 557
 558 unsigned int ff_layout_fetch_ds_ioerr(struct pnfs_layout_hdr *lo,
 559                                       const struct pnfs_layout_range *range,
 560                                       struct list_head *head,
 561                                       unsigned int maxnum)
 562 {
 563         unsigned int ret;
 564
 565         ret = do_layout_fetch_ds_ioerr(lo, range, head, maxnum);
 566         /* If we're over the max, discard all remaining entries */
 567         if (ret == maxnum) {
 568                 LIST_HEAD(discard);
 569                 do_layout_fetch_ds_ioerr(lo, range, &discard, -1);
 570                 ff_layout_free_ds_ioerr(&discard);
 571         }
 572         return ret;
 573 }
 574
 575 static bool ff_read_layout_has_available_ds(struct pnfs_layout_segment *lseg)
 576 {
 577         struct nfs4_ff_layout_mirror *mirror;
 578         struct nfs4_deviceid_node *devid;
 579         u32 idx;
 580
 581         for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) {
 582                 mirror = FF_LAYOUT_COMP(lseg, idx);
 583                 if (mirror) {
 584                         if (!mirror->mirror_ds)
 585                                 return true;
 586                         if (IS_ERR(mirror->mirror_ds))
 587                                 continue;
 588                         devid = &mirror->mirror_ds->id_node;
 589                         if (!ff_layout_test_devid_unavailable(devid))
 590                                 return true;
 591                 }
 592         }
 593
 594         return false;
 595 }
 596
 597 static bool ff_rw_layout_has_available_ds(struct pnfs_layout_segment *lseg)
 598 {
 599         struct nfs4_ff_layout_mirror *mirror;
 600         struct nfs4_deviceid_node *devid;
 601         u32 idx;
 602
 603         for (idx = 0; idx < FF_LAYOUT_MIRROR_COUNT(lseg); idx++) {
 604                 mirror = FF_LAYOUT_COMP(lseg, idx);
 605                 if (!mirror || IS_ERR(mirror->mirror_ds))
 606                         return false;
 607                 if (!mirror->mirror_ds)
 608                         continue;
 609                 devid = &mirror->mirror_ds->id_node;
 610                 if (ff_layout_test_devid_unavailable(devid))
 611                         return false;
 612         }
 613
 614         return FF_LAYOUT_MIRROR_COUNT(lseg) != 0;
 615 }
 616
 617 static bool ff_layout_has_available_ds(struct pnfs_layout_segment *lseg)
 618 {
 619         if (lseg->pls_range.iomode == IOMODE_READ)
 620                 return  ff_read_layout_has_available_ds(lseg);
 621         /* Note: RW layout needs all mirrors available */
 622         return ff_rw_layout_has_available_ds(lseg);
 623 }
 624
 625 bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg)
 626 {
 627         return ff_layout_no_fallback_to_mds(lseg) ||
 628                ff_layout_has_available_ds(lseg);
 629 }
 630
 631 bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg)
 632 {
 633         return lseg->pls_range.iomode == IOMODE_RW &&
 634                ff_layout_no_read_on_rw(lseg);
 635 }
 636
 637 module_param(dataserver_retrans, uint, 0644);
 638 MODULE_PARM_DESC(dataserver_retrans, "The  number of times the NFSv4.1 client "
 639                         "retries a request before it attempts further "
 640                         " recovery  action.");
 641 module_param(dataserver_timeo, uint, 0644);
 642 MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the "
 643                         "NFSv4.1  client  waits for a response from a "
 644                         " data server before it retries an NFS request.");