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         struct page *scratch;
 313
 314         /* set up xdr stream */
 315         scratch = alloc_page(gfp_flags);
 316         if (!scratch)
 317                 goto out_err;
 318
 319         xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen);
 320         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 321
 322         /* Get the stripe count (number of stripe index) */
 323         p = xdr_inline_decode(&stream, 4);
 324         if (unlikely(!p))
 325                 goto out_err_free_scratch;
 326
 327         cnt = be32_to_cpup(p);
 328         dprintk("%s stripe count  %d\n", __func__, cnt);
 329         if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
 330                 printk(KERN_WARNING "%s: stripe count %d greater than "
 331                        "supported maximum %d\n", __func__,
 332                         cnt, NFS4_PNFS_MAX_STRIPE_CNT);
 333                 goto out_err_free_scratch;
 334         }
 335
 336         /* read stripe indices */
 337         stripe_indices = kcalloc(cnt, sizeof(u8), gfp_flags);
 338         if (!stripe_indices)
 339                 goto out_err_free_scratch;
 340
 341         p = xdr_inline_decode(&stream, cnt << 2);
 342         if (unlikely(!p))
 343                 goto out_err_free_stripe_indices;
 344
 345         indexp = &stripe_indices[0];
 346         max_stripe_index = 0;
 347         for (i = 0; i < cnt; i++) {
 348                 *indexp = be32_to_cpup(p++);
 349                 max_stripe_index = max(max_stripe_index, *indexp);
 350                 indexp++;
 351         }
 352
 353         /* Check the multipath list count */
 354         p = xdr_inline_decode(&stream, 4);
 355         if (unlikely(!p))
 356                 goto out_err_free_stripe_indices;
 357
 358         num = be32_to_cpup(p);
 359         dprintk("%s ds_num %u\n", __func__, num);
 360         if (num > NFS4_PNFS_MAX_MULTI_CNT) {
 361                 printk(KERN_WARNING "%s: multipath count %d greater than "
 362                         "supported maximum %d\n", __func__,
 363                         num, NFS4_PNFS_MAX_MULTI_CNT);
 364                 goto out_err_free_stripe_indices;
 365         }
 366
 367         /* validate stripe indices are all < num */
 368         if (max_stripe_index >= num) {
 369                 printk(KERN_WARNING "%s: stripe index %u >= num ds %u\n",
 370                         __func__, max_stripe_index, num);
 371                 goto out_err_free_stripe_indices;
 372         }
 373
 374         dsaddr = kzalloc(sizeof(*dsaddr) +
 375                         (sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
 376                         gfp_flags);
 377         if (!dsaddr)
 378                 goto out_err_free_stripe_indices;
 379
 380         dsaddr->stripe_count = cnt;
 381         dsaddr->stripe_indices = stripe_indices;
 382         stripe_indices = NULL;
 383         dsaddr->ds_num = num;
 384         nfs4_init_deviceid_node(&dsaddr->id_node,
 385                                 NFS_SERVER(ino)->pnfs_curr_ld,
 386                                 NFS_SERVER(ino)->nfs_client,
 387                                 &pdev->dev_id);
 388
 389         for (i = 0; i < dsaddr->ds_num; i++) {
 390                 int j;
 391                 u32 mp_count;
 392
 393                 p = xdr_inline_decode(&stream, 4);
 394                 if (unlikely(!p))
 395                         goto out_err_free_deviceid;
 396
 397                 mp_count = be32_to_cpup(p); /* multipath count */
 398                 if (mp_count > 1) {
 399                         printk(KERN_WARNING
 400                                "%s: Multipath count %d not supported, "
 401                                "skipping all greater than 1\n", __func__,
 402                                 mp_count);
 403                 }
 404                 for (j = 0; j < mp_count; j++) {
 405                         if (j == 0) {
 406                                 dsaddr->ds_list[i] = decode_and_add_ds(&stream,
 407                                         ino, gfp_flags);
 408                                 if (dsaddr->ds_list[i] == NULL)
 409                                         goto out_err_free_deviceid;
 410                         } else {
 411                                 u32 len;
 412                                 /* skip extra multipath */
 413
 414                                 /* read len, skip */
 415                                 p = xdr_inline_decode(&stream, 4);
 416                                 if (unlikely(!p))
 417                                         goto out_err_free_deviceid;
 418                                 len = be32_to_cpup(p);
 419
 420                                 p = xdr_inline_decode(&stream, len);
 421                                 if (unlikely(!p))
 422                                         goto out_err_free_deviceid;
 423
 424                                 /* read len, skip */
 425                                 p = xdr_inline_decode(&stream, 4);
 426                                 if (unlikely(!p))
 427                                         goto out_err_free_deviceid;
 428                                 len = be32_to_cpup(p);
 429
 430                                 p = xdr_inline_decode(&stream, len);
 431                                 if (unlikely(!p))
 432                                         goto out_err_free_deviceid;
 433                         }
 434                 }
 435         }
 436
 437         __free_page(scratch);
 438         return dsaddr;
 439
 440 out_err_free_deviceid:
 441         nfs4_fl_free_deviceid(dsaddr);
 442         /* stripe_indicies was part of dsaddr */
 443         goto out_err_free_scratch;
 444 out_err_free_stripe_indices:
 445         kfree(stripe_indices);
 446 out_err_free_scratch:
 447         __free_page(scratch);
 448 out_err:
 449         dprintk("%s ERROR: returning NULL\n", __func__);
 450         return NULL;
 451 }
 452
 453 /*
 454  * Decode the opaque device specified in 'dev' and add it to the cache of
 455  * available devices.
 456  */
 457 static struct nfs4_file_layout_dsaddr *
 458 decode_and_add_device(struct inode *inode, struct pnfs_device *dev, gfp_t gfp_flags)
 459 {
 460         struct nfs4_deviceid_node *d;
 461         struct nfs4_file_layout_dsaddr *n, *new;
 462
 463         new = decode_device(inode, dev, gfp_flags);
 464         if (!new) {
 465                 printk(KERN_WARNING "%s: Could not decode or add device\n",
 466                         __func__);
 467                 return NULL;
 468         }
 469
 470         d = nfs4_insert_deviceid_node(&new->id_node);
 471         n = container_of(d, struct nfs4_file_layout_dsaddr, id_node);
 472         if (n != new) {
 473                 nfs4_fl_free_deviceid(new);
 474                 return n;
 475         }
 476
 477         return new;
 478 }
 479
 480 /*
 481  * Retrieve the information for dev_id, add it to the list
 482  * of available devices, and return it.
 483  */
 484 struct nfs4_file_layout_dsaddr *
 485 get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id, gfp_t gfp_flags)
 486 {
 487         struct pnfs_device *pdev = NULL;
 488         u32 max_resp_sz;
 489         int max_pages;
 490         struct page **pages = NULL;
 491         struct nfs4_file_layout_dsaddr *dsaddr = NULL;
 492         int rc, i;
 493         struct nfs_server *server = NFS_SERVER(inode);
 494
 495         /*
 496          * Use the session max response size as the basis for setting
 497          * GETDEVICEINFO's maxcount
 498          */
 499         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 500         max_pages = max_resp_sz >> PAGE_SHIFT;
 501         dprintk("%s inode %p max_resp_sz %u max_pages %d\n",
 502                 __func__, inode, max_resp_sz, max_pages);
 503
 504         pdev = kzalloc(sizeof(struct pnfs_device), gfp_flags);
 505         if (pdev == NULL)
 506                 return NULL;
 507
 508         pages = kzalloc(max_pages * sizeof(struct page *), gfp_flags);
 509         if (pages == NULL) {
 510                 kfree(pdev);
 511                 return NULL;
 512         }
 513         for (i = 0; i < max_pages; i++) {
 514                 pages[i] = alloc_page(gfp_flags);
 515                 if (!pages[i])
 516                         goto out_free;
 517         }
 518
 519         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 520         pdev->layout_type = LAYOUT_NFSV4_1_FILES;
 521         pdev->pages = pages;
 522         pdev->pgbase = 0;
 523         pdev->pglen = PAGE_SIZE * max_pages;
 524         pdev->mincount = 0;
 525
 526         rc = nfs4_proc_getdeviceinfo(server, pdev);
 527         dprintk("%s getdevice info returns %d\n", __func__, rc);
 528         if (rc)
 529                 goto out_free;
 530
 531         /*
 532          * Found new device, need to decode it and then add it to the
 533          * list of known devices for this mountpoint.
 534          */
 535         dsaddr = decode_and_add_device(inode, pdev, gfp_flags);
 536 out_free:
 537         for (i = 0; i < max_pages; i++)
 538                 __free_page(pages[i]);
 539         kfree(pages);
 540         kfree(pdev);
 541         dprintk("<-- %s dsaddr %p\n", __func__, dsaddr);
 542         return dsaddr;
 543 }
 544
 545 void
 546 nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 547 {
 548         nfs4_put_deviceid_node(&dsaddr->id_node);
 549 }
 550
 551 /*
 552  * Want res = (offset - layout->pattern_offset)/ layout->stripe_unit
 553  * Then: ((res + fsi) % dsaddr->stripe_count)
 554  */
 555 u32
 556 nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset)
 557 {
 558         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 559         u64 tmp;
 560
 561         tmp = offset - flseg->pattern_offset;
 562         do_div(tmp, flseg->stripe_unit);
 563         tmp += flseg->first_stripe_index;
 564         return do_div(tmp, flseg->dsaddr->stripe_count);
 565 }
 566
 567 u32
 568 nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j)
 569 {
 570         return FILELAYOUT_LSEG(lseg)->dsaddr->stripe_indices[j];
 571 }
 572
 573 struct nfs_fh *
 574 nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j)
 575 {
 576         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 577         u32 i;
 578
 579         if (flseg->stripe_type == STRIPE_SPARSE) {
 580                 if (flseg->num_fh == 1)
 581                         i = 0;
 582                 else if (flseg->num_fh == 0)
 583                         /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
 584                         return NULL;
 585                 else
 586                         i = nfs4_fl_calc_ds_index(lseg, j);
 587         } else
 588                 i = j;
 589         return flseg->fh_array[i];
 590 }
 591
 592 static void
 593 filelayout_mark_devid_negative(struct nfs4_file_layout_dsaddr *dsaddr,
 594                                int err, u32 ds_addr)
 595 {
 596         u32 *p = (u32 *)&dsaddr->id_node.deviceid;
 597
 598         printk(KERN_ERR "NFS: data server %x connection error %d."
 599                 " Deviceid [%x%x%x%x] marked out of use.\n",
 600                 ds_addr, err, p[0], p[1], p[2], p[3]);
 601
 602         spin_lock(&nfs4_ds_cache_lock);
 603         dsaddr->flags |= NFS4_DEVICE_ID_NEG_ENTRY;
 604         spin_unlock(&nfs4_ds_cache_lock);
 605 }
 606
 607 struct nfs4_pnfs_ds *
 608 nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
 609 {
 610         struct nfs4_file_layout_dsaddr *dsaddr = FILELAYOUT_LSEG(lseg)->dsaddr;
 611         struct nfs4_pnfs_ds *ds = dsaddr->ds_list[ds_idx];
 612
 613         if (ds == NULL) {
 614                 printk(KERN_ERR "%s: No data server for offset index %d\n",
 615                         __func__, ds_idx);
 616                 return NULL;
 617         }
 618
 619         if (!ds->ds_clp) {
 620                 struct nfs_server *s = NFS_SERVER(lseg->pls_layout->plh_inode);
 621                 int err;
 622
 623                 if (dsaddr->flags & NFS4_DEVICE_ID_NEG_ENTRY) {
 624                         /* Already tried to connect, don't try again */
 625                         dprintk("%s Deviceid marked out of use\n", __func__);
 626                         return NULL;
 627                 }
 628                 err = nfs4_ds_connect(s, ds);
 629                 if (err) {
 630                         filelayout_mark_devid_negative(dsaddr, err,
 631                                                        ntohl(ds->ds_ip_addr));
 632                         return NULL;
 633                 }
 634         }
 635         return ds;
 636 }