fs/nfs/filelayout/filelayoutdev.c

   1 /*
   2  *  Device operations for the pnfs nfs4 file layout driver.
   3  *
   4  *  Copyright (c) 2002
   5  *  The Regents of the University of Michigan
   6  *  All Rights Reserved
   7  *
   8  *  Dean Hildebrand <dhildebz@umich.edu>
   9  *  Garth Goodson   <Garth.Goodson@netapp.com>
  10  *
  11  *  Permission is granted to use, copy, create derivative works, and
  12  *  redistribute this software and such derivative works for any purpose,
  13  *  so long as the name of the University of Michigan is not used in
  14  *  any advertising or publicity pertaining to the use or distribution
  15  *  of this software without specific, written prior authorization. If
  16  *  the above copyright notice or any other identification of the
  17  *  University of Michigan is included in any copy of any portion of
  18  *  this software, then the disclaimer below must also be included.
  19  *
  20  *  This software is provided as is, without representation or warranty
  21  *  of any kind either express or implied, including without limitation
  22  *  the implied warranties of merchantability, fitness for a particular
  23  *  purpose, or noninfringement.  The Regents of the University of
  24  *  Michigan shall not be liable for any damages, including special,
  25  *  indirect, incidental, or consequential damages, with respect to any
  26  *  claim arising out of or in connection with the use of the software,
  27  *  even if it has been or is hereafter advised of the possibility of
  28  *  such damages.
  29  */
  30
  31 #include <linux/nfs_fs.h>
  32 #include <linux/vmalloc.h>
  33 #include <linux/module.h>
  34 #include <linux/sunrpc/addr.h>
  35
  36 #include "../internal.h"
  37 #include "../nfs4session.h"
  38 #include "filelayout.h"
  39
  40 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  41
  42 static unsigned int dataserver_timeo = NFS4_DEF_DS_TIMEO;
  43 static unsigned int dataserver_retrans = NFS4_DEF_DS_RETRANS;
  44
  45 /*
  46  * Data server cache
  47  *
  48  * Data servers can be mapped to different device ids.
  49  * nfs4_pnfs_ds reference counting
  50  *   - set to 1 on allocation
  51  *   - incremented when a device id maps a data server already in the cache.
  52  *   - decremented when deviceid is removed from the cache.
  53  */
  54 static DEFINE_SPINLOCK(nfs4_ds_cache_lock);
  55 static LIST_HEAD(nfs4_data_server_cache);
  56
  57 /* Debug routines */
  58 void
  59 print_ds(struct nfs4_pnfs_ds *ds)
  60 {
  61         if (ds == NULL) {
  62                 printk("%s NULL device\n", __func__);
  63                 return;
  64         }
  65         printk("        ds %s\n"
  66                 "        ref count %d\n"
  67                 "        client %p\n"
  68                 "        cl_exchange_flags %x\n",
  69                 ds->ds_remotestr,
  70                 atomic_read(&ds->ds_count), ds->ds_clp,
  71                 ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
  72 }
  73
  74 static bool
  75 same_sockaddr(struct sockaddr *addr1, struct sockaddr *addr2)
  76 {
  77         struct sockaddr_in *a, *b;
  78         struct sockaddr_in6 *a6, *b6;
  79
  80         if (addr1->sa_family != addr2->sa_family)
  81                 return false;
  82
  83         switch (addr1->sa_family) {
  84         case AF_INET:
  85                 a = (struct sockaddr_in *)addr1;
  86                 b = (struct sockaddr_in *)addr2;
  87
  88                 if (a->sin_addr.s_addr == b->sin_addr.s_addr &&
  89                     a->sin_port == b->sin_port)
  90                         return true;
  91                 break;
  92
  93         case AF_INET6:
  94                 a6 = (struct sockaddr_in6 *)addr1;
  95                 b6 = (struct sockaddr_in6 *)addr2;
  96
  97                 /* LINKLOCAL addresses must have matching scope_id */
  98                 if (ipv6_addr_src_scope(&a6->sin6_addr) ==
  99                     IPV6_ADDR_SCOPE_LINKLOCAL &&
 100                     a6->sin6_scope_id != b6->sin6_scope_id)
 101                         return false;
 102
 103                 if (ipv6_addr_equal(&a6->sin6_addr, &b6->sin6_addr) &&
 104                     a6->sin6_port == b6->sin6_port)
 105                         return true;
 106                 break;
 107
 108         default:
 109                 dprintk("%s: unhandled address family: %u\n",
 110                         __func__, addr1->sa_family);
 111                 return false;
 112         }
 113
 114         return false;
 115 }
 116
 117 static bool
 118 _same_data_server_addrs_locked(const struct list_head *dsaddrs1,
 119                                const struct list_head *dsaddrs2)
 120 {
 121         struct nfs4_pnfs_ds_addr *da1, *da2;
 122
 123         /* step through both lists, comparing as we go */
 124         for (da1 = list_first_entry(dsaddrs1, typeof(*da1), da_node),
 125              da2 = list_first_entry(dsaddrs2, typeof(*da2), da_node);
 126              da1 != NULL && da2 != NULL;
 127              da1 = list_entry(da1->da_node.next, typeof(*da1), da_node),
 128              da2 = list_entry(da2->da_node.next, typeof(*da2), da_node)) {
 129                 if (!same_sockaddr((struct sockaddr *)&da1->da_addr,
 130                                    (struct sockaddr *)&da2->da_addr))
 131                         return false;
 132         }
 133         if (da1 == NULL && da2 == NULL)
 134                 return true;
 135
 136         return false;
 137 }
 138
 139 /*
 140  * Lookup DS by addresses.  nfs4_ds_cache_lock is held
 141  */
 142 static struct nfs4_pnfs_ds *
 143 _data_server_lookup_locked(const struct list_head *dsaddrs)
 144 {
 145         struct nfs4_pnfs_ds *ds;
 146
 147         list_for_each_entry(ds, &nfs4_data_server_cache, ds_node)
 148                 if (_same_data_server_addrs_locked(&ds->ds_addrs, dsaddrs))
 149                         return ds;
 150         return NULL;
 151 }
 152
 153 /*
 154  * Create an rpc connection to the nfs4_pnfs_ds data server
 155  * Currently only supports IPv4 and IPv6 addresses
 156  */
 157 static int
 158 nfs4_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds)
 159 {
 160         struct nfs_client *clp = ERR_PTR(-EIO);
 161         struct nfs4_pnfs_ds_addr *da;
 162         int status = 0;
 163
 164         dprintk("--> %s DS %s au_flavor %d\n", __func__, ds->ds_remotestr,
 165                 mds_srv->nfs_client->cl_rpcclient->cl_auth->au_flavor);
 166
 167         list_for_each_entry(da, &ds->ds_addrs, da_node) {
 168                 dprintk("%s: DS %s: trying address %s\n",
 169                         __func__, ds->ds_remotestr, da->da_remotestr);
 170
 171                 clp = nfs4_set_ds_client(mds_srv->nfs_client,
 172                                         (struct sockaddr *)&da->da_addr,
 173                                         da->da_addrlen, IPPROTO_TCP,
 174                                         dataserver_timeo, dataserver_retrans);
 175                 if (!IS_ERR(clp))
 176                         break;
 177         }
 178
 179         if (IS_ERR(clp)) {
 180                 status = PTR_ERR(clp);
 181                 goto out;
 182         }
 183
 184         status = nfs4_init_ds_session(clp, mds_srv->nfs_client->cl_lease_time);
 185         if (status)
 186                 goto out_put;
 187
 188         smp_wmb();
 189         ds->ds_clp = clp;
 190         dprintk("%s [new] addr: %s\n", __func__, ds->ds_remotestr);
 191 out:
 192         return status;
 193 out_put:
 194         nfs_put_client(clp);
 195         goto out;
 196 }
 197
 198 static void
 199 destroy_ds(struct nfs4_pnfs_ds *ds)
 200 {
 201         struct nfs4_pnfs_ds_addr *da;
 202
 203         dprintk("--> %s\n", __func__);
 204         ifdebug(FACILITY)
 205                 print_ds(ds);
 206
 207         if (ds->ds_clp)
 208                 nfs_put_client(ds->ds_clp);
 209
 210         while (!list_empty(&ds->ds_addrs)) {
 211                 da = list_first_entry(&ds->ds_addrs,
 212                                       struct nfs4_pnfs_ds_addr,
 213                                       da_node);
 214                 list_del_init(&da->da_node);
 215                 kfree(da->da_remotestr);
 216                 kfree(da);
 217         }
 218
 219         kfree(ds->ds_remotestr);
 220         kfree(ds);
 221 }
 222
 223 void
 224 nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 225 {
 226         struct nfs4_pnfs_ds *ds;
 227         int i;
 228
 229         nfs4_print_deviceid(&dsaddr->id_node.deviceid);
 230
 231         for (i = 0; i < dsaddr->ds_num; i++) {
 232                 ds = dsaddr->ds_list[i];
 233                 if (ds != NULL) {
 234                         if (atomic_dec_and_lock(&ds->ds_count,
 235                                                 &nfs4_ds_cache_lock)) {
 236                                 list_del_init(&ds->ds_node);
 237                                 spin_unlock(&nfs4_ds_cache_lock);
 238                                 destroy_ds(ds);
 239                         }
 240                 }
 241         }
 242         kfree(dsaddr->stripe_indices);
 243         kfree(dsaddr);
 244 }
 245
 246 /*
 247  * Create a string with a human readable address and port to avoid
 248  * complicated setup around many dprinks.
 249  */
 250 static char *
 251 nfs4_pnfs_remotestr(struct list_head *dsaddrs, gfp_t gfp_flags)
 252 {
 253         struct nfs4_pnfs_ds_addr *da;
 254         char *remotestr;
 255         size_t len;
 256         char *p;
 257
 258         len = 3;        /* '{', '}' and eol */
 259         list_for_each_entry(da, dsaddrs, da_node) {
 260                 len += strlen(da->da_remotestr) + 1;    /* string plus comma */
 261         }
 262
 263         remotestr = kzalloc(len, gfp_flags);
 264         if (!remotestr)
 265                 return NULL;
 266
 267         p = remotestr;
 268         *(p++) = '{';
 269         len--;
 270         list_for_each_entry(da, dsaddrs, da_node) {
 271                 size_t ll = strlen(da->da_remotestr);
 272
 273                 if (ll > len)
 274                         goto out_err;
 275
 276                 memcpy(p, da->da_remotestr, ll);
 277                 p += ll;
 278                 len -= ll;
 279
 280                 if (len < 1)
 281                         goto out_err;
 282                 (*p++) = ',';
 283                 len--;
 284         }
 285         if (len < 2)
 286                 goto out_err;
 287         *(p++) = '}';
 288         *p = '\0';
 289         return remotestr;
 290 out_err:
 291         kfree(remotestr);
 292         return NULL;
 293 }
 294
 295 static struct nfs4_pnfs_ds *
 296 nfs4_pnfs_ds_add(struct list_head *dsaddrs, gfp_t gfp_flags)
 297 {
 298         struct nfs4_pnfs_ds *tmp_ds, *ds = NULL;
 299         char *remotestr;
 300
 301         if (list_empty(dsaddrs)) {
 302                 dprintk("%s: no addresses defined\n", __func__);
 303                 goto out;
 304         }
 305
 306         ds = kzalloc(sizeof(*ds), gfp_flags);
 307         if (!ds)
 308                 goto out;
 309
 310         /* this is only used for debugging, so it's ok if its NULL */
 311         remotestr = nfs4_pnfs_remotestr(dsaddrs, gfp_flags);
 312
 313         spin_lock(&nfs4_ds_cache_lock);
 314         tmp_ds = _data_server_lookup_locked(dsaddrs);
 315         if (tmp_ds == NULL) {
 316                 INIT_LIST_HEAD(&ds->ds_addrs);
 317                 list_splice_init(dsaddrs, &ds->ds_addrs);
 318                 ds->ds_remotestr = remotestr;
 319                 atomic_set(&ds->ds_count, 1);
 320                 INIT_LIST_HEAD(&ds->ds_node);
 321                 ds->ds_clp = NULL;
 322                 list_add(&ds->ds_node, &nfs4_data_server_cache);
 323                 dprintk("%s add new data server %s\n", __func__,
 324                         ds->ds_remotestr);
 325         } else {
 326                 kfree(remotestr);
 327                 kfree(ds);
 328                 atomic_inc(&tmp_ds->ds_count);
 329                 dprintk("%s data server %s found, inc'ed ds_count to %d\n",
 330                         __func__, tmp_ds->ds_remotestr,
 331                         atomic_read(&tmp_ds->ds_count));
 332                 ds = tmp_ds;
 333         }
 334         spin_unlock(&nfs4_ds_cache_lock);
 335 out:
 336         return ds;
 337 }
 338
 339 /*
 340  * Currently only supports ipv4, ipv6 and one multi-path address.
 341  */
 342 static struct nfs4_pnfs_ds_addr *
 343 decode_ds_addr(struct net *net, struct xdr_stream *streamp, gfp_t gfp_flags)
 344 {
 345         struct nfs4_pnfs_ds_addr *da = NULL;
 346         char *buf, *portstr;
 347         __be16 port;
 348         int nlen, rlen;
 349         int tmp[2];
 350         __be32 *p;
 351         char *netid, *match_netid;
 352         size_t len, match_netid_len;
 353         char *startsep = "";
 354         char *endsep = "";
 355
 356
 357         /* r_netid */
 358         p = xdr_inline_decode(streamp, 4);
 359         if (unlikely(!p))
 360                 goto out_err;
 361         nlen = be32_to_cpup(p++);
 362
 363         p = xdr_inline_decode(streamp, nlen);
 364         if (unlikely(!p))
 365                 goto out_err;
 366
 367         netid = kmalloc(nlen+1, gfp_flags);
 368         if (unlikely(!netid))
 369                 goto out_err;
 370
 371         netid[nlen] = '\0';
 372         memcpy(netid, p, nlen);
 373
 374         /* r_addr: ip/ip6addr with port in dec octets - see RFC 5665 */
 375         p = xdr_inline_decode(streamp, 4);
 376         if (unlikely(!p))
 377                 goto out_free_netid;
 378         rlen = be32_to_cpup(p);
 379
 380         p = xdr_inline_decode(streamp, rlen);
 381         if (unlikely(!p))
 382                 goto out_free_netid;
 383
 384         /* port is ".ABC.DEF", 8 chars max */
 385         if (rlen > INET6_ADDRSTRLEN + IPV6_SCOPE_ID_LEN + 8) {
 386                 dprintk("%s: Invalid address, length %d\n", __func__,
 387                         rlen);
 388                 goto out_free_netid;
 389         }
 390         buf = kmalloc(rlen + 1, gfp_flags);
 391         if (!buf) {
 392                 dprintk("%s: Not enough memory\n", __func__);
 393                 goto out_free_netid;
 394         }
 395         buf[rlen] = '\0';
 396         memcpy(buf, p, rlen);
 397
 398         /* replace port '.' with '-' */
 399         portstr = strrchr(buf, '.');
 400         if (!portstr) {
 401                 dprintk("%s: Failed finding expected dot in port\n",
 402                         __func__);
 403                 goto out_free_buf;
 404         }
 405         *portstr = '-';
 406
 407         /* find '.' between address and port */
 408         portstr = strrchr(buf, '.');
 409         if (!portstr) {
 410                 dprintk("%s: Failed finding expected dot between address and "
 411                         "port\n", __func__);
 412                 goto out_free_buf;
 413         }
 414         *portstr = '\0';
 415
 416         da = kzalloc(sizeof(*da), gfp_flags);
 417         if (unlikely(!da))
 418                 goto out_free_buf;
 419
 420         INIT_LIST_HEAD(&da->da_node);
 421
 422         if (!rpc_pton(net, buf, portstr-buf, (struct sockaddr *)&da->da_addr,
 423                       sizeof(da->da_addr))) {
 424                 dprintk("%s: error parsing address %s\n", __func__, buf);
 425                 goto out_free_da;
 426         }
 427
 428         portstr++;
 429         sscanf(portstr, "%d-%d", &tmp[0], &tmp[1]);
 430         port = htons((tmp[0] << 8) | (tmp[1]));
 431
 432         switch (da->da_addr.ss_family) {
 433         case AF_INET:
 434                 ((struct sockaddr_in *)&da->da_addr)->sin_port = port;
 435                 da->da_addrlen = sizeof(struct sockaddr_in);
 436                 match_netid = "tcp";
 437                 match_netid_len = 3;
 438                 break;
 439
 440         case AF_INET6:
 441                 ((struct sockaddr_in6 *)&da->da_addr)->sin6_port = port;
 442                 da->da_addrlen = sizeof(struct sockaddr_in6);
 443                 match_netid = "tcp6";
 444                 match_netid_len = 4;
 445                 startsep = "[";
 446                 endsep = "]";
 447                 break;
 448
 449         default:
 450                 dprintk("%s: unsupported address family: %u\n",
 451                         __func__, da->da_addr.ss_family);
 452                 goto out_free_da;
 453         }
 454
 455         if (nlen != match_netid_len || strncmp(netid, match_netid, nlen)) {
 456                 dprintk("%s: ERROR: r_netid \"%s\" != \"%s\"\n",
 457                         __func__, netid, match_netid);
 458                 goto out_free_da;
 459         }
 460
 461         /* save human readable address */
 462         len = strlen(startsep) + strlen(buf) + strlen(endsep) + 7;
 463         da->da_remotestr = kzalloc(len, gfp_flags);
 464
 465         /* NULL is ok, only used for dprintk */
 466         if (da->da_remotestr)
 467                 snprintf(da->da_remotestr, len, "%s%s%s:%u", startsep,
 468                          buf, endsep, ntohs(port));
 469
 470         dprintk("%s: Parsed DS addr %s\n", __func__, da->da_remotestr);
 471         kfree(buf);
 472         kfree(netid);
 473         return da;
 474
 475 out_free_da:
 476         kfree(da);
 477 out_free_buf:
 478         dprintk("%s: Error parsing DS addr: %s\n", __func__, buf);
 479         kfree(buf);
 480 out_free_netid:
 481         kfree(netid);
 482 out_err:
 483         return NULL;
 484 }
 485
 486 /* Decode opaque device data and return the result */
 487 struct nfs4_file_layout_dsaddr *
 488 nfs4_fl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
 489                 gfp_t gfp_flags)
 490 {
 491         int i;
 492         u32 cnt, num;
 493         u8 *indexp;
 494         __be32 *p;
 495         u8 *stripe_indices;
 496         u8 max_stripe_index;
 497         struct nfs4_file_layout_dsaddr *dsaddr = NULL;
 498         struct xdr_stream stream;
 499         struct xdr_buf buf;
 500         struct page *scratch;
 501         struct list_head dsaddrs;
 502         struct nfs4_pnfs_ds_addr *da;
 503
 504         /* set up xdr stream */
 505         scratch = alloc_page(gfp_flags);
 506         if (!scratch)
 507                 goto out_err;
 508
 509         xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen);
 510         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 511
 512         /* Get the stripe count (number of stripe index) */
 513         p = xdr_inline_decode(&stream, 4);
 514         if (unlikely(!p))
 515                 goto out_err_free_scratch;
 516
 517         cnt = be32_to_cpup(p);
 518         dprintk("%s stripe count  %d\n", __func__, cnt);
 519         if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
 520                 printk(KERN_WARNING "NFS: %s: stripe count %d greater than "
 521                        "supported maximum %d\n", __func__,
 522                         cnt, NFS4_PNFS_MAX_STRIPE_CNT);
 523                 goto out_err_free_scratch;
 524         }
 525
 526         /* read stripe indices */
 527         stripe_indices = kcalloc(cnt, sizeof(u8), gfp_flags);
 528         if (!stripe_indices)
 529                 goto out_err_free_scratch;
 530
 531         p = xdr_inline_decode(&stream, cnt << 2);
 532         if (unlikely(!p))
 533                 goto out_err_free_stripe_indices;
 534
 535         indexp = &stripe_indices[0];
 536         max_stripe_index = 0;
 537         for (i = 0; i < cnt; i++) {
 538                 *indexp = be32_to_cpup(p++);
 539                 max_stripe_index = max(max_stripe_index, *indexp);
 540                 indexp++;
 541         }
 542
 543         /* Check the multipath list count */
 544         p = xdr_inline_decode(&stream, 4);
 545         if (unlikely(!p))
 546                 goto out_err_free_stripe_indices;
 547
 548         num = be32_to_cpup(p);
 549         dprintk("%s ds_num %u\n", __func__, num);
 550         if (num > NFS4_PNFS_MAX_MULTI_CNT) {
 551                 printk(KERN_WARNING "NFS: %s: multipath count %d greater than "
 552                         "supported maximum %d\n", __func__,
 553                         num, NFS4_PNFS_MAX_MULTI_CNT);
 554                 goto out_err_free_stripe_indices;
 555         }
 556
 557         /* validate stripe indices are all < num */
 558         if (max_stripe_index >= num) {
 559                 printk(KERN_WARNING "NFS: %s: stripe index %u >= num ds %u\n",
 560                         __func__, max_stripe_index, num);
 561                 goto out_err_free_stripe_indices;
 562         }
 563
 564         dsaddr = kzalloc(sizeof(*dsaddr) +
 565                         (sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
 566                         gfp_flags);
 567         if (!dsaddr)
 568                 goto out_err_free_stripe_indices;
 569
 570         dsaddr->stripe_count = cnt;
 571         dsaddr->stripe_indices = stripe_indices;
 572         stripe_indices = NULL;
 573         dsaddr->ds_num = num;
 574         nfs4_init_deviceid_node(&dsaddr->id_node, server, &pdev->dev_id);
 575
 576         INIT_LIST_HEAD(&dsaddrs);
 577
 578         for (i = 0; i < dsaddr->ds_num; i++) {
 579                 int j;
 580                 u32 mp_count;
 581
 582                 p = xdr_inline_decode(&stream, 4);
 583                 if (unlikely(!p))
 584                         goto out_err_free_deviceid;
 585
 586                 mp_count = be32_to_cpup(p); /* multipath count */
 587                 for (j = 0; j < mp_count; j++) {
 588                         da = decode_ds_addr(server->nfs_client->cl_net,
 589                                             &stream, gfp_flags);
 590                         if (da)
 591                                 list_add_tail(&da->da_node, &dsaddrs);
 592                 }
 593                 if (list_empty(&dsaddrs)) {
 594                         dprintk("%s: no suitable DS addresses found\n",
 595                                 __func__);
 596                         goto out_err_free_deviceid;
 597                 }
 598
 599                 dsaddr->ds_list[i] = nfs4_pnfs_ds_add(&dsaddrs, gfp_flags);
 600                 if (!dsaddr->ds_list[i])
 601                         goto out_err_drain_dsaddrs;
 602
 603                 /* If DS was already in cache, free ds addrs */
 604                 while (!list_empty(&dsaddrs)) {
 605                         da = list_first_entry(&dsaddrs,
 606                                               struct nfs4_pnfs_ds_addr,
 607                                               da_node);
 608                         list_del_init(&da->da_node);
 609                         kfree(da->da_remotestr);
 610                         kfree(da);
 611                 }
 612         }
 613
 614         __free_page(scratch);
 615         return dsaddr;
 616
 617 out_err_drain_dsaddrs:
 618         while (!list_empty(&dsaddrs)) {
 619                 da = list_first_entry(&dsaddrs, struct nfs4_pnfs_ds_addr,
 620                                       da_node);
 621                 list_del_init(&da->da_node);
 622                 kfree(da->da_remotestr);
 623                 kfree(da);
 624         }
 625 out_err_free_deviceid:
 626         nfs4_fl_free_deviceid(dsaddr);
 627         /* stripe_indicies was part of dsaddr */
 628         goto out_err_free_scratch;
 629 out_err_free_stripe_indices:
 630         kfree(stripe_indices);
 631 out_err_free_scratch:
 632         __free_page(scratch);
 633 out_err:
 634         dprintk("%s ERROR: returning NULL\n", __func__);
 635         return NULL;
 636 }
 637
 638 void
 639 nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 640 {
 641         nfs4_put_deviceid_node(&dsaddr->id_node);
 642 }
 643
 644 /*
 645  * Want res = (offset - layout->pattern_offset)/ layout->stripe_unit
 646  * Then: ((res + fsi) % dsaddr->stripe_count)
 647  */
 648 u32
 649 nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset)
 650 {
 651         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 652         u64 tmp;
 653
 654         tmp = offset - flseg->pattern_offset;
 655         do_div(tmp, flseg->stripe_unit);
 656         tmp += flseg->first_stripe_index;
 657         return do_div(tmp, flseg->dsaddr->stripe_count);
 658 }
 659
 660 u32
 661 nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j)
 662 {
 663         return FILELAYOUT_LSEG(lseg)->dsaddr->stripe_indices[j];
 664 }
 665
 666 struct nfs_fh *
 667 nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j)
 668 {
 669         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 670         u32 i;
 671
 672         if (flseg->stripe_type == STRIPE_SPARSE) {
 673                 if (flseg->num_fh == 1)
 674                         i = 0;
 675                 else if (flseg->num_fh == 0)
 676                         /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
 677                         return NULL;
 678                 else
 679                         i = nfs4_fl_calc_ds_index(lseg, j);
 680         } else
 681                 i = j;
 682         return flseg->fh_array[i];
 683 }
 684
 685 static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
 686 {
 687         might_sleep();
 688         wait_on_bit_action(&ds->ds_state, NFS4DS_CONNECTING,
 689                            nfs_wait_bit_killable, TASK_KILLABLE);
 690 }
 691
 692 static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
 693 {
 694         smp_mb__before_atomic();
 695         clear_bit(NFS4DS_CONNECTING, &ds->ds_state);
 696         smp_mb__after_atomic();
 697         wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING);
 698 }
 699
 700
 701 struct nfs4_pnfs_ds *
 702 nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
 703 {
 704         struct nfs4_file_layout_dsaddr *dsaddr = FILELAYOUT_LSEG(lseg)->dsaddr;
 705         struct nfs4_pnfs_ds *ds = dsaddr->ds_list[ds_idx];
 706         struct nfs4_deviceid_node *devid = FILELAYOUT_DEVID_NODE(lseg);
 707         struct nfs4_pnfs_ds *ret = ds;
 708
 709         if (ds == NULL) {
 710                 printk(KERN_ERR "NFS: %s: No data server for offset index %d\n",
 711                         __func__, ds_idx);
 712                 filelayout_mark_devid_invalid(devid);
 713                 goto out;
 714         }
 715         smp_rmb();
 716         if (ds->ds_clp)
 717                 goto out_test_devid;
 718
 719         if (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) == 0) {
 720                 struct nfs_server *s = NFS_SERVER(lseg->pls_layout->plh_inode);
 721                 int err;
 722
 723                 err = nfs4_ds_connect(s, ds);
 724                 if (err)
 725                         nfs4_mark_deviceid_unavailable(devid);
 726                 nfs4_clear_ds_conn_bit(ds);
 727         } else {
 728                 /* Either ds is connected, or ds is NULL */
 729                 nfs4_wait_ds_connect(ds);
 730         }
 731 out_test_devid:
 732         if (filelayout_test_devid_unavailable(devid))
 733                 ret = NULL;
 734 out:
 735         return ret;
 736 }
 737
 738 module_param(dataserver_retrans, uint, 0644);
 739 MODULE_PARM_DESC(dataserver_retrans, "The  number of times the NFSv4.1 client "
 740                         "retries a request before it attempts further "
 741                         " recovery  action.");
 742 module_param(dataserver_timeo, uint, 0644);
 743 MODULE_PARM_DESC(dataserver_timeo, "The time (in tenths of a second) the "
 744                         "NFSv4.1  client  waits for a response from a "
 745                         " data server before it retries an NFS request.");