fs/nfs/nfs4filelayoutdev.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
  34 #include "internal.h"
  35 #include "nfs4filelayout.h"
  36
  37 #define NFSDBG_FACILITY         NFSDBG_PNFS_LD
  38
  39 /*
  40  * Data server cache
  41  *
  42  * Data servers can be mapped to different device ids.
  43  * nfs4_pnfs_ds reference counting
  44  *   - set to 1 on allocation
  45  *   - incremented when a device id maps a data server already in the cache.
  46  *   - decremented when deviceid is removed from the cache.
  47  */
  48 DEFINE_SPINLOCK(nfs4_ds_cache_lock);
  49 static LIST_HEAD(nfs4_data_server_cache);
  50
  51 /* Debug routines */
  52 void
  53 print_ds(struct nfs4_pnfs_ds *ds)
  54 {
  55         if (ds == NULL) {
  56                 printk("%s NULL device\n", __func__);
  57                 return;
  58         }
  59         printk("        ip_addr %x port %hu\n"
  60                 "        ref count %d\n"
  61                 "        client %p\n"
  62                 "        cl_exchange_flags %x\n",
  63                 ntohl(ds->ds_ip_addr), ntohs(ds->ds_port),
  64                 atomic_read(&ds->ds_count), ds->ds_clp,
  65                 ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
  66 }
  67
  68 /* nfs4_ds_cache_lock is held */
  69 static struct nfs4_pnfs_ds *
  70 _data_server_lookup_locked(u32 ip_addr, u32 port)
  71 {
  72         struct nfs4_pnfs_ds *ds;
  73
  74         dprintk("_data_server_lookup: ip_addr=%x port=%hu\n",
  75                         ntohl(ip_addr), ntohs(port));
  76
  77         list_for_each_entry(ds, &nfs4_data_server_cache, ds_node) {
  78                 if (ds->ds_ip_addr == ip_addr &&
  79                     ds->ds_port == port) {
  80                         return ds;
  81                 }
  82         }
  83         return NULL;
  84 }
  85
  86 /*
  87  * Create an rpc connection to the nfs4_pnfs_ds data server
  88  * Currently only support IPv4
  89  */
  90 static int
  91 nfs4_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds)
  92 {
  93         struct nfs_client *clp;
  94         struct sockaddr_in sin;
  95         int status = 0;
  96
  97         dprintk("--> %s ip:port %x:%hu au_flavor %d\n", __func__,
  98                 ntohl(ds->ds_ip_addr), ntohs(ds->ds_port),
  99                 mds_srv->nfs_client->cl_rpcclient->cl_auth->au_flavor);
 100
 101         sin.sin_family = AF_INET;
 102         sin.sin_addr.s_addr = ds->ds_ip_addr;
 103         sin.sin_port = ds->ds_port;
 104
 105         clp = nfs4_set_ds_client(mds_srv->nfs_client, (struct sockaddr *)&sin,
 106                                  sizeof(sin), IPPROTO_TCP);
 107         if (IS_ERR(clp)) {
 108                 status = PTR_ERR(clp);
 109                 goto out;
 110         }
 111
 112         if ((clp->cl_exchange_flags & EXCHGID4_FLAG_MASK_PNFS) != 0) {
 113                 if (!is_ds_client(clp)) {
 114                         status = -ENODEV;
 115                         goto out_put;
 116                 }
 117                 ds->ds_clp = clp;
 118                 dprintk("%s [existing] ip=%x, port=%hu\n", __func__,
 119                         ntohl(ds->ds_ip_addr), ntohs(ds->ds_port));
 120                 goto out;
 121         }
 122
 123         /*
 124          * Do not set NFS_CS_CHECK_LEASE_TIME instead set the DS lease to
 125          * be equal to the MDS lease. Renewal is scheduled in create_session.
 126          */
 127         spin_lock(&mds_srv->nfs_client->cl_lock);
 128         clp->cl_lease_time = mds_srv->nfs_client->cl_lease_time;
 129         spin_unlock(&mds_srv->nfs_client->cl_lock);
 130         clp->cl_last_renewal = jiffies;
 131
 132         /* New nfs_client */
 133         status = nfs4_init_ds_session(clp);
 134         if (status)
 135                 goto out_put;
 136
 137         ds->ds_clp = clp;
 138         dprintk("%s [new] ip=%x, port=%hu\n", __func__, ntohl(ds->ds_ip_addr),
 139                 ntohs(ds->ds_port));
 140 out:
 141         return status;
 142 out_put:
 143         nfs_put_client(clp);
 144         goto out;
 145 }
 146
 147 static void
 148 destroy_ds(struct nfs4_pnfs_ds *ds)
 149 {
 150         dprintk("--> %s\n", __func__);
 151         ifdebug(FACILITY)
 152                 print_ds(ds);
 153
 154         if (ds->ds_clp)
 155                 nfs_put_client(ds->ds_clp);
 156         kfree(ds);
 157 }
 158
 159 void
 160 nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 161 {
 162         struct nfs4_pnfs_ds *ds;
 163         int i;
 164
 165         nfs4_print_deviceid(&dsaddr->id_node.deviceid);
 166
 167         for (i = 0; i < dsaddr->ds_num; i++) {
 168                 ds = dsaddr->ds_list[i];
 169                 if (ds != NULL) {
 170                         if (atomic_dec_and_lock(&ds->ds_count,
 171                                                 &nfs4_ds_cache_lock)) {
 172                                 list_del_init(&ds->ds_node);
 173                                 spin_unlock(&nfs4_ds_cache_lock);
 174                                 destroy_ds(ds);
 175                         }
 176                 }
 177         }
 178         kfree(dsaddr->stripe_indices);
 179         kfree(dsaddr);
 180 }
 181
 182 static struct nfs4_pnfs_ds *
 183 nfs4_pnfs_ds_add(struct inode *inode, u32 ip_addr, u32 port, gfp_t gfp_flags)
 184 {
 185         struct nfs4_pnfs_ds *tmp_ds, *ds;
 186
 187         ds = kzalloc(sizeof(*tmp_ds), gfp_flags);
 188         if (!ds)
 189                 goto out;
 190
 191         spin_lock(&nfs4_ds_cache_lock);
 192         tmp_ds = _data_server_lookup_locked(ip_addr, port);
 193         if (tmp_ds == NULL) {
 194                 ds->ds_ip_addr = ip_addr;
 195                 ds->ds_port = port;
 196                 atomic_set(&ds->ds_count, 1);
 197                 INIT_LIST_HEAD(&ds->ds_node);
 198                 ds->ds_clp = NULL;
 199                 list_add(&ds->ds_node, &nfs4_data_server_cache);
 200                 dprintk("%s add new data server ip 0x%x\n", __func__,
 201                         ds->ds_ip_addr);
 202         } else {
 203                 kfree(ds);
 204                 atomic_inc(&tmp_ds->ds_count);
 205                 dprintk("%s data server found ip 0x%x, inc'ed ds_count to %d\n",
 206                         __func__, tmp_ds->ds_ip_addr,
 207                         atomic_read(&tmp_ds->ds_count));
 208                 ds = tmp_ds;
 209         }
 210         spin_unlock(&nfs4_ds_cache_lock);
 211 out:
 212         return ds;
 213 }
 214
 215 /*
 216  * Currently only support ipv4, and one multi-path address.
 217  */
 218 static struct nfs4_pnfs_ds *
 219 decode_and_add_ds(struct xdr_stream *streamp, struct inode *inode, gfp_t gfp_flags)
 220 {
 221         struct nfs4_pnfs_ds *ds = NULL;
 222         char *buf;
 223         const char *ipend, *pstr;
 224         u32 ip_addr, port;
 225         int nlen, rlen, i;
 226         int tmp[2];
 227         __be32 *p;
 228
 229         /* r_netid */
 230         p = xdr_inline_decode(streamp, 4);
 231         if (unlikely(!p))
 232                 goto out_err;
 233         nlen = be32_to_cpup(p++);
 234
 235         p = xdr_inline_decode(streamp, nlen);
 236         if (unlikely(!p))
 237                 goto out_err;
 238
 239         /* Check that netid is "tcp" */
 240         if (nlen != 3 ||  memcmp((char *)p, "tcp", 3)) {
 241                 dprintk("%s: ERROR: non ipv4 TCP r_netid\n", __func__);
 242                 goto out_err;
 243         }
 244
 245         /* r_addr */
 246         p = xdr_inline_decode(streamp, 4);
 247         if (unlikely(!p))
 248                 goto out_err;
 249         rlen = be32_to_cpup(p);
 250
 251         p = xdr_inline_decode(streamp, rlen);
 252         if (unlikely(!p))
 253                 goto out_err;
 254
 255         /* ipv6 length plus port is legal */
 256         if (rlen > INET6_ADDRSTRLEN + 8) {
 257                 dprintk("%s: Invalid address, length %d\n", __func__,
 258                         rlen);
 259                 goto out_err;
 260         }
 261         buf = kmalloc(rlen + 1, gfp_flags);
 262         if (!buf) {
 263                 dprintk("%s: Not enough memory\n", __func__);
 264                 goto out_err;
 265         }
 266         buf[rlen] = '\0';
 267         memcpy(buf, p, rlen);
 268
 269         /* replace the port dots with dashes for the in4_pton() delimiter*/
 270         for (i = 0; i < 2; i++) {
 271                 char *res = strrchr(buf, '.');
 272                 if (!res) {
 273                         dprintk("%s: Failed finding expected dots in port\n",
 274                                 __func__);
 275                         goto out_free;
 276                 }
 277                 *res = '-';
 278         }
 279
 280         /* Currently only support ipv4 address */
 281         if (in4_pton(buf, rlen, (u8 *)&ip_addr, '-', &ipend) == 0) {
 282                 dprintk("%s: Only ipv4 addresses supported\n", __func__);
 283                 goto out_free;
 284         }
 285
 286         /* port */
 287         pstr = ipend;
 288         sscanf(pstr, "-%d-%d", &tmp[0], &tmp[1]);
 289         port = htons((tmp[0] << 8) | (tmp[1]));
 290
 291         ds = nfs4_pnfs_ds_add(inode, ip_addr, port, gfp_flags);
 292         dprintk("%s: Decoded address and port %s\n", __func__, buf);
 293 out_free:
 294         kfree(buf);
 295 out_err:
 296         return ds;
 297 }
 298
 299 /* Decode opaque device data and return the result */
 300 static struct nfs4_file_layout_dsaddr*
 301 decode_device(struct inode *ino, struct pnfs_device *pdev, gfp_t gfp_flags)
 302 {
 303         int i;
 304         u32 cnt, num;
 305         u8 *indexp;
 306         __be32 *p;
 307         u8 *stripe_indices;
 308         u8 max_stripe_index;
 309         struct nfs4_file_layout_dsaddr *dsaddr = NULL;
 310         struct xdr_stream stream;
 311         struct xdr_buf buf = {
 312                 .pages = pdev->pages,
 313                 .page_len = pdev->pglen,
 314                 .buflen = pdev->pglen,
 315                 .len = pdev->pglen,
 316         };
 317         struct page *scratch;
 318
 319         /* set up xdr stream */
 320         scratch = alloc_page(gfp_flags);
 321         if (!scratch)
 322                 goto out_err;
 323
 324         xdr_init_decode(&stream, &buf, NULL);
 325         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 326
 327         /* Get the stripe count (number of stripe index) */
 328         p = xdr_inline_decode(&stream, 4);
 329         if (unlikely(!p))
 330                 goto out_err_free_scratch;
 331
 332         cnt = be32_to_cpup(p);
 333         dprintk("%s stripe count  %d\n", __func__, cnt);
 334         if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
 335                 printk(KERN_WARNING "%s: stripe count %d greater than "
 336                        "supported maximum %d\n", __func__,
 337                         cnt, NFS4_PNFS_MAX_STRIPE_CNT);
 338                 goto out_err_free_scratch;
 339         }
 340
 341         /* read stripe indices */
 342         stripe_indices = kcalloc(cnt, sizeof(u8), gfp_flags);
 343         if (!stripe_indices)
 344                 goto out_err_free_scratch;
 345
 346         p = xdr_inline_decode(&stream, cnt << 2);
 347         if (unlikely(!p))
 348                 goto out_err_free_stripe_indices;
 349
 350         indexp = &stripe_indices[0];
 351         max_stripe_index = 0;
 352         for (i = 0; i < cnt; i++) {
 353                 *indexp = be32_to_cpup(p++);
 354                 max_stripe_index = max(max_stripe_index, *indexp);
 355                 indexp++;
 356         }
 357
 358         /* Check the multipath list count */
 359         p = xdr_inline_decode(&stream, 4);
 360         if (unlikely(!p))
 361                 goto out_err_free_stripe_indices;
 362
 363         num = be32_to_cpup(p);
 364         dprintk("%s ds_num %u\n", __func__, num);
 365         if (num > NFS4_PNFS_MAX_MULTI_CNT) {
 366                 printk(KERN_WARNING "%s: multipath count %d greater than "
 367                         "supported maximum %d\n", __func__,
 368                         num, NFS4_PNFS_MAX_MULTI_CNT);
 369                 goto out_err_free_stripe_indices;
 370         }
 371
 372         /* validate stripe indices are all < num */
 373         if (max_stripe_index >= num) {
 374                 printk(KERN_WARNING "%s: stripe index %u >= num ds %u\n",
 375                         __func__, max_stripe_index, num);
 376                 goto out_err_free_stripe_indices;
 377         }
 378
 379         dsaddr = kzalloc(sizeof(*dsaddr) +
 380                         (sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
 381                         gfp_flags);
 382         if (!dsaddr)
 383                 goto out_err_free_stripe_indices;
 384
 385         dsaddr->stripe_count = cnt;
 386         dsaddr->stripe_indices = stripe_indices;
 387         stripe_indices = NULL;
 388         dsaddr->ds_num = num;
 389         nfs4_init_deviceid_node(&dsaddr->id_node,
 390                                 NFS_SERVER(ino)->pnfs_curr_ld,
 391                                 NFS_SERVER(ino)->nfs_client,
 392                                 &pdev->dev_id);
 393
 394         for (i = 0; i < dsaddr->ds_num; i++) {
 395                 int j;
 396                 u32 mp_count;
 397
 398                 p = xdr_inline_decode(&stream, 4);
 399                 if (unlikely(!p))
 400                         goto out_err_free_deviceid;
 401
 402                 mp_count = be32_to_cpup(p); /* multipath count */
 403                 if (mp_count > 1) {
 404                         printk(KERN_WARNING
 405                                "%s: Multipath count %d not supported, "
 406                                "skipping all greater than 1\n", __func__,
 407                                 mp_count);
 408                 }
 409                 for (j = 0; j < mp_count; j++) {
 410                         if (j == 0) {
 411                                 dsaddr->ds_list[i] = decode_and_add_ds(&stream,
 412                                         ino, gfp_flags);
 413                                 if (dsaddr->ds_list[i] == NULL)
 414                                         goto out_err_free_deviceid;
 415                         } else {
 416                                 u32 len;
 417                                 /* skip extra multipath */
 418
 419                                 /* read len, skip */
 420                                 p = xdr_inline_decode(&stream, 4);
 421                                 if (unlikely(!p))
 422                                         goto out_err_free_deviceid;
 423                                 len = be32_to_cpup(p);
 424
 425                                 p = xdr_inline_decode(&stream, len);
 426                                 if (unlikely(!p))
 427                                         goto out_err_free_deviceid;
 428
 429                                 /* read len, skip */
 430                                 p = xdr_inline_decode(&stream, 4);
 431                                 if (unlikely(!p))
 432                                         goto out_err_free_deviceid;
 433                                 len = be32_to_cpup(p);
 434
 435                                 p = xdr_inline_decode(&stream, len);
 436                                 if (unlikely(!p))
 437                                         goto out_err_free_deviceid;
 438                         }
 439                 }
 440         }
 441
 442         __free_page(scratch);
 443         return dsaddr;
 444
 445 out_err_free_deviceid:
 446         nfs4_fl_free_deviceid(dsaddr);
 447         /* stripe_indicies was part of dsaddr */
 448         goto out_err_free_scratch;
 449 out_err_free_stripe_indices:
 450         kfree(stripe_indices);
 451 out_err_free_scratch:
 452         __free_page(scratch);
 453 out_err:
 454         dprintk("%s ERROR: returning NULL\n", __func__);
 455         return NULL;
 456 }
 457
 458 /*
 459  * Decode the opaque device specified in 'dev' and add it to the cache of
 460  * available devices.
 461  */
 462 static struct nfs4_file_layout_dsaddr *
 463 decode_and_add_device(struct inode *inode, struct pnfs_device *dev, gfp_t gfp_flags)
 464 {
 465         struct nfs4_deviceid_node *d;
 466         struct nfs4_file_layout_dsaddr *n, *new;
 467
 468         new = decode_device(inode, dev, gfp_flags);
 469         if (!new) {
 470                 printk(KERN_WARNING "%s: Could not decode or add device\n",
 471                         __func__);
 472                 return NULL;
 473         }
 474
 475         d = nfs4_insert_deviceid_node(&new->id_node);
 476         n = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
 477         if (n != new) {
 478                 nfs4_fl_free_deviceid(new);
 479                 return n;
 480         }
 481
 482         return new;
 483 }
 484
 485 /*
 486  * Retrieve the information for dev_id, add it to the list
 487  * of available devices, and return it.
 488  */
 489 struct nfs4_file_layout_dsaddr *
 490 get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id, gfp_t gfp_flags)
 491 {
 492         struct pnfs_device *pdev = NULL;
 493         u32 max_resp_sz;
 494         int max_pages;
 495         struct page **pages = NULL;
 496         struct nfs4_file_layout_dsaddr *dsaddr = NULL;
 497         int rc, i;
 498         struct nfs_server *server = NFS_SERVER(inode);
 499
 500         /*
 501          * Use the session max response size as the basis for setting
 502          * GETDEVICEINFO's maxcount
 503          */
 504         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 505         max_pages = max_resp_sz >> PAGE_SHIFT;
 506         dprintk("%s inode %p max_resp_sz %u max_pages %d\n",
 507                 __func__, inode, max_resp_sz, max_pages);
 508
 509         pdev = kzalloc(sizeof(struct pnfs_device), gfp_flags);
 510         if (pdev == NULL)
 511                 return NULL;
 512
 513         pages = kzalloc(max_pages * sizeof(struct page *), gfp_flags);
 514         if (pages == NULL) {
 515                 kfree(pdev);
 516                 return NULL;
 517         }
 518         for (i = 0; i < max_pages; i++) {
 519                 pages[i] = alloc_page(gfp_flags);
 520                 if (!pages[i])
 521                         goto out_free;
 522         }
 523
 524         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 525         pdev->layout_type = LAYOUT_NFSV4_1_FILES;
 526         pdev->pages = pages;
 527         pdev->pgbase = 0;
 528         pdev->pglen = PAGE_SIZE * max_pages;
 529         pdev->mincount = 0;
 530
 531         rc = nfs4_proc_getdeviceinfo(server, pdev);
 532         dprintk("%s getdevice info returns %d\n", __func__, rc);
 533         if (rc)
 534                 goto out_free;
 535
 536         /*
 537          * Found new device, need to decode it and then add it to the
 538          * list of known devices for this mountpoint.
 539          */
 540         dsaddr = decode_and_add_device(inode, pdev, gfp_flags);
 541 out_free:
 542         for (i = 0; i < max_pages; i++)
 543                 __free_page(pages[i]);
 544         kfree(pages);
 545         kfree(pdev);
 546         dprintk("<-- %s dsaddr %p\n", __func__, dsaddr);
 547         return dsaddr;
 548 }
 549
 550 void
 551 nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 552 {
 553         nfs4_put_deviceid_node(&dsaddr->id_node);
 554 }
 555
 556 /*
 557  * Want res = (offset - layout->pattern_offset)/ layout->stripe_unit
 558  * Then: ((res + fsi) % dsaddr->stripe_count)
 559  */
 560 u32
 561 nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset)
 562 {
 563         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 564         u64 tmp;
 565
 566         tmp = offset - flseg->pattern_offset;
 567         do_div(tmp, flseg->stripe_unit);
 568         tmp += flseg->first_stripe_index;
 569         return do_div(tmp, flseg->dsaddr->stripe_count);
 570 }
 571
 572 u32
 573 nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j)
 574 {
 575         return FILELAYOUT_LSEG(lseg)->dsaddr->stripe_indices[j];
 576 }
 577
 578 struct nfs_fh *
 579 nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j)
 580 {
 581         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 582         u32 i;
 583
 584         if (flseg->stripe_type == STRIPE_SPARSE) {
 585                 if (flseg->num_fh == 1)
 586                         i = 0;
 587                 else if (flseg->num_fh == 0)
 588                         /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
 589                         return NULL;
 590                 else
 591                         i = nfs4_fl_calc_ds_index(lseg, j);
 592         } else
 593                 i = j;
 594         return flseg->fh_array[i];
 595 }
 596
 597 static void
 598 filelayout_mark_devid_negative(struct nfs4_file_layout_dsaddr *dsaddr,
 599                                int err, u32 ds_addr)
 600 {
 601         u32 *p = (u32 *)&dsaddr->id_node.deviceid;
 602
 603         printk(KERN_ERR "NFS: data server %x connection error %d."
 604                 " Deviceid [%x%x%x%x] marked out of use.\n",
 605                 ds_addr, err, p[0], p[1], p[2], p[3]);
 606
 607         spin_lock(&nfs4_ds_cache_lock);
 608         dsaddr->flags |= NFS4_DEVICE_ID_NEG_ENTRY;
 609         spin_unlock(&nfs4_ds_cache_lock);
 610 }
 611
 612 struct nfs4_pnfs_ds *
 613 nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
 614 {
 615         struct nfs4_file_layout_dsaddr *dsaddr = FILELAYOUT_LSEG(lseg)->dsaddr;
 616         struct nfs4_pnfs_ds *ds = dsaddr->ds_list[ds_idx];
 617
 618         if (ds == NULL) {
 619                 printk(KERN_ERR "%s: No data server for offset index %d\n",
 620                         __func__, ds_idx);
 621                 return NULL;
 622         }
 623
 624         if (!ds->ds_clp) {
 625                 struct nfs_server *s = NFS_SERVER(lseg->pls_layout->plh_inode);
 626                 int err;
 627
 628                 if (dsaddr->flags & NFS4_DEVICE_ID_NEG_ENTRY) {
 629                         /* Already tried to connect, don't try again */
 630                         dprintk("%s Deviceid marked out of use\n", __func__);
 631                         return NULL;
 632                 }
 633                 err = nfs4_ds_connect(s, ds);
 634                 if (err) {
 635                         filelayout_mark_devid_negative(dsaddr, err,
 636                                                        ntohl(ds->ds_ip_addr));
 637                         return NULL;
 638                 }
 639         }
 640         return ds;
 641 }