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  * Device ID RCU cache. A device ID is unique per client ID and layout type.
  41  */
  42 #define NFS4_FL_DEVICE_ID_HASH_BITS     5
  43 #define NFS4_FL_DEVICE_ID_HASH_SIZE     (1 << NFS4_FL_DEVICE_ID_HASH_BITS)
  44 #define NFS4_FL_DEVICE_ID_HASH_MASK     (NFS4_FL_DEVICE_ID_HASH_SIZE - 1)
  45
  46 static inline u32
  47 nfs4_fl_deviceid_hash(struct nfs4_deviceid *id)
  48 {
  49         unsigned char *cptr = (unsigned char *)id->data;
  50         unsigned int nbytes = NFS4_DEVICEID4_SIZE;
  51         u32 x = 0;
  52
  53         while (nbytes--) {
  54                 x *= 37;
  55                 x += *cptr++;
  56         }
  57         return x & NFS4_FL_DEVICE_ID_HASH_MASK;
  58 }
  59
  60 static struct hlist_head filelayout_deviceid_cache[NFS4_FL_DEVICE_ID_HASH_SIZE];
  61 static DEFINE_SPINLOCK(filelayout_deviceid_lock);
  62
  63 /*
  64  * Data server cache
  65  *
  66  * Data servers can be mapped to different device ids.
  67  * nfs4_pnfs_ds reference counting
  68  *   - set to 1 on allocation
  69  *   - incremented when a device id maps a data server already in the cache.
  70  *   - decremented when deviceid is removed from the cache.
  71  */
  72 DEFINE_SPINLOCK(nfs4_ds_cache_lock);
  73 static LIST_HEAD(nfs4_data_server_cache);
  74
  75 /* Debug routines */
  76 void
  77 print_ds(struct nfs4_pnfs_ds *ds)
  78 {
  79         if (ds == NULL) {
  80                 printk("%s NULL device\n", __func__);
  81                 return;
  82         }
  83         printk("        ip_addr %x port %hu\n"
  84                 "        ref count %d\n"
  85                 "        client %p\n"
  86                 "        cl_exchange_flags %x\n",
  87                 ntohl(ds->ds_ip_addr), ntohs(ds->ds_port),
  88                 atomic_read(&ds->ds_count), ds->ds_clp,
  89                 ds->ds_clp ? ds->ds_clp->cl_exchange_flags : 0);
  90 }
  91
  92 void
  93 print_ds_list(struct nfs4_file_layout_dsaddr *dsaddr)
  94 {
  95         int i;
  96
  97         ifdebug(FACILITY) {
  98                 printk("%s dsaddr->ds_num %d\n", __func__,
  99                        dsaddr->ds_num);
 100                 for (i = 0; i < dsaddr->ds_num; i++)
 101                         print_ds(dsaddr->ds_list[i]);
 102         }
 103 }
 104
 105 void print_deviceid(struct nfs4_deviceid *id)
 106 {
 107         u32 *p = (u32 *)id;
 108
 109         dprintk("%s: device id= [%x%x%x%x]\n", __func__,
 110                 p[0], p[1], p[2], p[3]);
 111 }
 112
 113 /* nfs4_ds_cache_lock is held */
 114 static struct nfs4_pnfs_ds *
 115 _data_server_lookup_locked(u32 ip_addr, u32 port)
 116 {
 117         struct nfs4_pnfs_ds *ds;
 118
 119         dprintk("_data_server_lookup: ip_addr=%x port=%hu\n",
 120                         ntohl(ip_addr), ntohs(port));
 121
 122         list_for_each_entry(ds, &nfs4_data_server_cache, ds_node) {
 123                 if (ds->ds_ip_addr == ip_addr &&
 124                     ds->ds_port == port) {
 125                         return ds;
 126                 }
 127         }
 128         return NULL;
 129 }
 130
 131 /*
 132  * Create an rpc connection to the nfs4_pnfs_ds data server
 133  * Currently only support IPv4
 134  */
 135 static int
 136 nfs4_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds)
 137 {
 138         struct nfs_client *clp;
 139         struct sockaddr_in sin;
 140         int status = 0;
 141
 142         dprintk("--> %s ip:port %x:%hu au_flavor %d\n", __func__,
 143                 ntohl(ds->ds_ip_addr), ntohs(ds->ds_port),
 144                 mds_srv->nfs_client->cl_rpcclient->cl_auth->au_flavor);
 145
 146         sin.sin_family = AF_INET;
 147         sin.sin_addr.s_addr = ds->ds_ip_addr;
 148         sin.sin_port = ds->ds_port;
 149
 150         clp = nfs4_set_ds_client(mds_srv->nfs_client, (struct sockaddr *)&sin,
 151                                  sizeof(sin), IPPROTO_TCP);
 152         if (IS_ERR(clp)) {
 153                 status = PTR_ERR(clp);
 154                 goto out;
 155         }
 156
 157         if ((clp->cl_exchange_flags & EXCHGID4_FLAG_MASK_PNFS) != 0) {
 158                 if (!is_ds_client(clp)) {
 159                         status = -ENODEV;
 160                         goto out_put;
 161                 }
 162                 ds->ds_clp = clp;
 163                 dprintk("%s [existing] ip=%x, port=%hu\n", __func__,
 164                         ntohl(ds->ds_ip_addr), ntohs(ds->ds_port));
 165                 goto out;
 166         }
 167
 168         /*
 169          * Do not set NFS_CS_CHECK_LEASE_TIME instead set the DS lease to
 170          * be equal to the MDS lease. Renewal is scheduled in create_session.
 171          */
 172         spin_lock(&mds_srv->nfs_client->cl_lock);
 173         clp->cl_lease_time = mds_srv->nfs_client->cl_lease_time;
 174         spin_unlock(&mds_srv->nfs_client->cl_lock);
 175         clp->cl_last_renewal = jiffies;
 176
 177         /* New nfs_client */
 178         status = nfs4_init_ds_session(clp);
 179         if (status)
 180                 goto out_put;
 181
 182         ds->ds_clp = clp;
 183         dprintk("%s [new] ip=%x, port=%hu\n", __func__, ntohl(ds->ds_ip_addr),
 184                 ntohs(ds->ds_port));
 185 out:
 186         return status;
 187 out_put:
 188         nfs_put_client(clp);
 189         goto out;
 190 }
 191
 192 static void
 193 destroy_ds(struct nfs4_pnfs_ds *ds)
 194 {
 195         dprintk("--> %s\n", __func__);
 196         ifdebug(FACILITY)
 197                 print_ds(ds);
 198
 199         if (ds->ds_clp)
 200                 nfs_put_client(ds->ds_clp);
 201         kfree(ds);
 202 }
 203
 204 static void
 205 nfs4_fl_free_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 206 {
 207         struct nfs4_pnfs_ds *ds;
 208         int i;
 209
 210         print_deviceid(&dsaddr->deviceid);
 211
 212         for (i = 0; i < dsaddr->ds_num; i++) {
 213                 ds = dsaddr->ds_list[i];
 214                 if (ds != NULL) {
 215                         if (atomic_dec_and_lock(&ds->ds_count,
 216                                                 &nfs4_ds_cache_lock)) {
 217                                 list_del_init(&ds->ds_node);
 218                                 spin_unlock(&nfs4_ds_cache_lock);
 219                                 destroy_ds(ds);
 220                         }
 221                 }
 222         }
 223         kfree(dsaddr->stripe_indices);
 224         kfree(dsaddr);
 225 }
 226
 227 static struct nfs4_pnfs_ds *
 228 nfs4_pnfs_ds_add(struct inode *inode, u32 ip_addr, u32 port)
 229 {
 230         struct nfs4_pnfs_ds *tmp_ds, *ds;
 231
 232         ds = kzalloc(sizeof(*tmp_ds), GFP_KERNEL);
 233         if (!ds)
 234                 goto out;
 235
 236         spin_lock(&nfs4_ds_cache_lock);
 237         tmp_ds = _data_server_lookup_locked(ip_addr, port);
 238         if (tmp_ds == NULL) {
 239                 ds->ds_ip_addr = ip_addr;
 240                 ds->ds_port = port;
 241                 atomic_set(&ds->ds_count, 1);
 242                 INIT_LIST_HEAD(&ds->ds_node);
 243                 ds->ds_clp = NULL;
 244                 list_add(&ds->ds_node, &nfs4_data_server_cache);
 245                 dprintk("%s add new data server ip 0x%x\n", __func__,
 246                         ds->ds_ip_addr);
 247         } else {
 248                 kfree(ds);
 249                 atomic_inc(&tmp_ds->ds_count);
 250                 dprintk("%s data server found ip 0x%x, inc'ed ds_count to %d\n",
 251                         __func__, tmp_ds->ds_ip_addr,
 252                         atomic_read(&tmp_ds->ds_count));
 253                 ds = tmp_ds;
 254         }
 255         spin_unlock(&nfs4_ds_cache_lock);
 256 out:
 257         return ds;
 258 }
 259
 260 /*
 261  * Currently only support ipv4, and one multi-path address.
 262  */
 263 static struct nfs4_pnfs_ds *
 264 decode_and_add_ds(__be32 **pp, struct inode *inode)
 265 {
 266         struct nfs4_pnfs_ds *ds = NULL;
 267         char *buf;
 268         const char *ipend, *pstr;
 269         u32 ip_addr, port;
 270         int nlen, rlen, i;
 271         int tmp[2];
 272         __be32 *r_netid, *r_addr, *p = *pp;
 273
 274         /* r_netid */
 275         nlen = be32_to_cpup(p++);
 276         r_netid = p;
 277         p += XDR_QUADLEN(nlen);
 278
 279         /* r_addr */
 280         rlen = be32_to_cpup(p++);
 281         r_addr = p;
 282         p += XDR_QUADLEN(rlen);
 283         *pp = p;
 284
 285         /* Check that netid is "tcp" */
 286         if (nlen != 3 ||  memcmp((char *)r_netid, "tcp", 3)) {
 287                 dprintk("%s: ERROR: non ipv4 TCP r_netid\n", __func__);
 288                 goto out_err;
 289         }
 290
 291         /* ipv6 length plus port is legal */
 292         if (rlen > INET6_ADDRSTRLEN + 8) {
 293                 dprintk("%s: Invalid address, length %d\n", __func__,
 294                         rlen);
 295                 goto out_err;
 296         }
 297         buf = kmalloc(rlen + 1, GFP_KERNEL);
 298         if (!buf) {
 299                 dprintk("%s: Not enough memory\n", __func__);
 300                 goto out_err;
 301         }
 302         buf[rlen] = '\0';
 303         memcpy(buf, r_addr, rlen);
 304
 305         /* replace the port dots with dashes for the in4_pton() delimiter*/
 306         for (i = 0; i < 2; i++) {
 307                 char *res = strrchr(buf, '.');
 308                 if (!res) {
 309                         dprintk("%s: Failed finding expected dots in port\n",
 310                                 __func__);
 311                         goto out_free;
 312                 }
 313                 *res = '-';
 314         }
 315
 316         /* Currently only support ipv4 address */
 317         if (in4_pton(buf, rlen, (u8 *)&ip_addr, '-', &ipend) == 0) {
 318                 dprintk("%s: Only ipv4 addresses supported\n", __func__);
 319                 goto out_free;
 320         }
 321
 322         /* port */
 323         pstr = ipend;
 324         sscanf(pstr, "-%d-%d", &tmp[0], &tmp[1]);
 325         port = htons((tmp[0] << 8) | (tmp[1]));
 326
 327         ds = nfs4_pnfs_ds_add(inode, ip_addr, port);
 328         dprintk("%s: Decoded address and port %s\n", __func__, buf);
 329 out_free:
 330         kfree(buf);
 331 out_err:
 332         return ds;
 333 }
 334
 335 /* Decode opaque device data and return the result */
 336 static struct nfs4_file_layout_dsaddr*
 337 decode_device(struct inode *ino, struct pnfs_device *pdev)
 338 {
 339         int i, dummy;
 340         u32 cnt, num;
 341         u8 *indexp;
 342         __be32 *p = (__be32 *)pdev->area, *indicesp;
 343         struct nfs4_file_layout_dsaddr *dsaddr;
 344
 345         /* Get the stripe count (number of stripe index) */
 346         cnt = be32_to_cpup(p++);
 347         dprintk("%s stripe count  %d\n", __func__, cnt);
 348         if (cnt > NFS4_PNFS_MAX_STRIPE_CNT) {
 349                 printk(KERN_WARNING "%s: stripe count %d greater than "
 350                        "supported maximum %d\n", __func__,
 351                         cnt, NFS4_PNFS_MAX_STRIPE_CNT);
 352                 goto out_err;
 353         }
 354
 355         /* Check the multipath list count */
 356         indicesp = p;
 357         p += XDR_QUADLEN(cnt << 2);
 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;
 365         }
 366         dsaddr = kzalloc(sizeof(*dsaddr) +
 367                         (sizeof(struct nfs4_pnfs_ds *) * (num - 1)),
 368                         GFP_KERNEL);
 369         if (!dsaddr)
 370                 goto out_err;
 371
 372         dsaddr->stripe_indices = kzalloc(sizeof(u8) * cnt, GFP_KERNEL);
 373         if (!dsaddr->stripe_indices)
 374                 goto out_err_free;
 375
 376         dsaddr->stripe_count = cnt;
 377         dsaddr->ds_num = num;
 378
 379         memcpy(&dsaddr->deviceid, &pdev->dev_id, sizeof(pdev->dev_id));
 380
 381         /* Go back an read stripe indices */
 382         p = indicesp;
 383         indexp = &dsaddr->stripe_indices[0];
 384         for (i = 0; i < dsaddr->stripe_count; i++) {
 385                 *indexp = be32_to_cpup(p++);
 386                 if (*indexp >= num)
 387                         goto out_err_free;
 388                 indexp++;
 389         }
 390         /* Skip already read multipath list count */
 391         p++;
 392
 393         for (i = 0; i < dsaddr->ds_num; i++) {
 394                 int j;
 395
 396                 dummy = be32_to_cpup(p++); /* multipath count */
 397                 if (dummy > 1) {
 398                         printk(KERN_WARNING
 399                                "%s: Multipath count %d not supported, "
 400                                "skipping all greater than 1\n", __func__,
 401                                 dummy);
 402                 }
 403                 for (j = 0; j < dummy; j++) {
 404                         if (j == 0) {
 405                                 dsaddr->ds_list[i] = decode_and_add_ds(&p, ino);
 406                                 if (dsaddr->ds_list[i] == NULL)
 407                                         goto out_err_free;
 408                         } else {
 409                                 u32 len;
 410                                 /* skip extra multipath */
 411                                 len = be32_to_cpup(p++);
 412                                 p += XDR_QUADLEN(len);
 413                                 len = be32_to_cpup(p++);
 414                                 p += XDR_QUADLEN(len);
 415                                 continue;
 416                         }
 417                 }
 418         }
 419         return dsaddr;
 420
 421 out_err_free:
 422         nfs4_fl_free_deviceid(dsaddr);
 423 out_err:
 424         dprintk("%s ERROR: returning NULL\n", __func__);
 425         return NULL;
 426 }
 427
 428 /*
 429  * Decode the opaque device specified in 'dev' and add it to the cache of
 430  * available devices.
 431  */
 432 static struct nfs4_file_layout_dsaddr *
 433 decode_and_add_device(struct inode *inode, struct pnfs_device *dev)
 434 {
 435         struct nfs4_file_layout_dsaddr *d, *new;
 436         long hash;
 437
 438         new = decode_device(inode, dev);
 439         if (!new) {
 440                 printk(KERN_WARNING "%s: Could not decode or add device\n",
 441                         __func__);
 442                 return NULL;
 443         }
 444
 445         spin_lock(&filelayout_deviceid_lock);
 446         d = nfs4_fl_find_get_deviceid(&new->deviceid);
 447         if (d) {
 448                 spin_unlock(&filelayout_deviceid_lock);
 449                 nfs4_fl_free_deviceid(new);
 450                 return d;
 451         }
 452
 453         INIT_HLIST_NODE(&new->node);
 454         atomic_set(&new->ref, 1);
 455         hash = nfs4_fl_deviceid_hash(&new->deviceid);
 456         hlist_add_head_rcu(&new->node, &filelayout_deviceid_cache[hash]);
 457         spin_unlock(&filelayout_deviceid_lock);
 458
 459         return new;
 460 }
 461
 462 /*
 463  * Retrieve the information for dev_id, add it to the list
 464  * of available devices, and return it.
 465  */
 466 struct nfs4_file_layout_dsaddr *
 467 get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id)
 468 {
 469         struct pnfs_device *pdev = NULL;
 470         u32 max_resp_sz;
 471         int max_pages;
 472         struct page **pages = NULL;
 473         struct nfs4_file_layout_dsaddr *dsaddr = NULL;
 474         int rc, i;
 475         struct nfs_server *server = NFS_SERVER(inode);
 476
 477         /*
 478          * Use the session max response size as the basis for setting
 479          * GETDEVICEINFO's maxcount
 480          */
 481         max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
 482         max_pages = max_resp_sz >> PAGE_SHIFT;
 483         dprintk("%s inode %p max_resp_sz %u max_pages %d\n",
 484                 __func__, inode, max_resp_sz, max_pages);
 485
 486         pdev = kzalloc(sizeof(struct pnfs_device), GFP_KERNEL);
 487         if (pdev == NULL)
 488                 return NULL;
 489
 490         pages = kzalloc(max_pages * sizeof(struct page *), GFP_KERNEL);
 491         if (pages == NULL) {
 492                 kfree(pdev);
 493                 return NULL;
 494         }
 495         for (i = 0; i < max_pages; i++) {
 496                 pages[i] = alloc_page(GFP_KERNEL);
 497                 if (!pages[i])
 498                         goto out_free;
 499         }
 500
 501         /* set pdev->area */
 502         pdev->area = vmap(pages, max_pages, VM_MAP, PAGE_KERNEL);
 503         if (!pdev->area)
 504                 goto out_free;
 505
 506         memcpy(&pdev->dev_id, dev_id, sizeof(*dev_id));
 507         pdev->layout_type = LAYOUT_NFSV4_1_FILES;
 508         pdev->pages = pages;
 509         pdev->pgbase = 0;
 510         pdev->pglen = PAGE_SIZE * max_pages;
 511         pdev->mincount = 0;
 512
 513         rc = nfs4_proc_getdeviceinfo(server, pdev);
 514         dprintk("%s getdevice info returns %d\n", __func__, rc);
 515         if (rc)
 516                 goto out_free;
 517
 518         /*
 519          * Found new device, need to decode it and then add it to the
 520          * list of known devices for this mountpoint.
 521          */
 522         dsaddr = decode_and_add_device(inode, pdev);
 523 out_free:
 524         if (pdev->area != NULL)
 525                 vunmap(pdev->area);
 526         for (i = 0; i < max_pages; i++)
 527                 __free_page(pages[i]);
 528         kfree(pages);
 529         kfree(pdev);
 530         dprintk("<-- %s dsaddr %p\n", __func__, dsaddr);
 531         return dsaddr;
 532 }
 533
 534 void
 535 nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr)
 536 {
 537         if (atomic_dec_and_lock(&dsaddr->ref, &filelayout_deviceid_lock)) {
 538                 hlist_del_rcu(&dsaddr->node);
 539                 spin_unlock(&filelayout_deviceid_lock);
 540
 541                 synchronize_rcu();
 542                 nfs4_fl_free_deviceid(dsaddr);
 543         }
 544 }
 545
 546 struct nfs4_file_layout_dsaddr *
 547 nfs4_fl_find_get_deviceid(struct nfs4_deviceid *id)
 548 {
 549         struct nfs4_file_layout_dsaddr *d;
 550         struct hlist_node *n;
 551         long hash = nfs4_fl_deviceid_hash(id);
 552
 553
 554         rcu_read_lock();
 555         hlist_for_each_entry_rcu(d, n, &filelayout_deviceid_cache[hash], node) {
 556                 if (!memcmp(&d->deviceid, id, sizeof(*id))) {
 557                         if (!atomic_inc_not_zero(&d->ref))
 558                                 goto fail;
 559                         rcu_read_unlock();
 560                         return d;
 561                 }
 562         }
 563 fail:
 564         rcu_read_unlock();
 565         return NULL;
 566 }
 567
 568 /*
 569  * Want res = (offset - layout->pattern_offset)/ layout->stripe_unit
 570  * Then: ((res + fsi) % dsaddr->stripe_count)
 571  */
 572 u32
 573 nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset)
 574 {
 575         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 576         u64 tmp;
 577
 578         tmp = offset - flseg->pattern_offset;
 579         do_div(tmp, flseg->stripe_unit);
 580         tmp += flseg->first_stripe_index;
 581         return do_div(tmp, flseg->dsaddr->stripe_count);
 582 }
 583
 584 u32
 585 nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j)
 586 {
 587         return FILELAYOUT_LSEG(lseg)->dsaddr->stripe_indices[j];
 588 }
 589
 590 struct nfs_fh *
 591 nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j)
 592 {
 593         struct nfs4_filelayout_segment *flseg = FILELAYOUT_LSEG(lseg);
 594         u32 i;
 595
 596         if (flseg->stripe_type == STRIPE_SPARSE) {
 597                 if (flseg->num_fh == 1)
 598                         i = 0;
 599                 else if (flseg->num_fh == 0)
 600                         /* Use the MDS OPEN fh set in nfs_read_rpcsetup */
 601                         return NULL;
 602                 else
 603                         i = nfs4_fl_calc_ds_index(lseg, j);
 604         } else
 605                 i = j;
 606         return flseg->fh_array[i];
 607 }
 608
 609 static void
 610 filelayout_mark_devid_negative(struct nfs4_file_layout_dsaddr *dsaddr,
 611                                int err, u32 ds_addr)
 612 {
 613         u32 *p = (u32 *)&dsaddr->deviceid;
 614
 615         printk(KERN_ERR "NFS: data server %x connection error %d."
 616                 " Deviceid [%x%x%x%x] marked out of use.\n",
 617                 ds_addr, err, p[0], p[1], p[2], p[3]);
 618
 619         spin_lock(&filelayout_deviceid_lock);
 620         dsaddr->flags |= NFS4_DEVICE_ID_NEG_ENTRY;
 621         spin_unlock(&filelayout_deviceid_lock);
 622 }
 623
 624 struct nfs4_pnfs_ds *
 625 nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx)
 626 {
 627         struct nfs4_file_layout_dsaddr *dsaddr = FILELAYOUT_LSEG(lseg)->dsaddr;
 628         struct nfs4_pnfs_ds *ds = dsaddr->ds_list[ds_idx];
 629
 630         if (ds == NULL) {
 631                 printk(KERN_ERR "%s: No data server for offset index %d\n",
 632                         __func__, ds_idx);
 633                 return NULL;
 634         }
 635
 636         if (!ds->ds_clp) {
 637                 struct nfs_server *s = NFS_SERVER(lseg->pls_layout->plh_inode);
 638                 int err;
 639
 640                 if (dsaddr->flags & NFS4_DEVICE_ID_NEG_ENTRY) {
 641                         /* Already tried to connect, don't try again */
 642                         dprintk("%s Deviceid marked out of use\n", __func__);
 643                         return NULL;
 644                 }
 645                 err = nfs4_ds_connect(s, ds);
 646                 if (err) {
 647                         filelayout_mark_devid_negative(dsaddr, err,
 648                                                        ntohl(ds->ds_ip_addr));
 649                         return NULL;
 650                 }
 651         }
 652         return ds;
 653 }