fs/nfs/callback_proc.c

   1 /*
   2  * linux/fs/nfs/callback_proc.c
   3  *
   4  * Copyright (C) 2004 Trond Myklebust
   5  *
   6  * NFSv4 callback procedures
   7  */
   8 #include <linux/nfs4.h>
   9 #include <linux/nfs_fs.h>
  10 #include <linux/slab.h>
  11 #include <linux/rcupdate.h>
  12 #include "nfs4_fs.h"
  13 #include "callback.h"
  14 #include "delegation.h"
  15 #include "internal.h"
  16 #include "pnfs.h"
  17 #include "nfs4session.h"
  18 #include "nfs4trace.h"
  19
  20 #define NFSDBG_FACILITY NFSDBG_CALLBACK
  21
  22 __be32 nfs4_callback_getattr(struct cb_getattrargs *args,
  23                              struct cb_getattrres *res,
  24                              struct cb_process_state *cps)
  25 {
  26         struct nfs_delegation *delegation;
  27         struct nfs_inode *nfsi;
  28         struct inode *inode;
  29
  30         res->status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
  31         if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
  32                 goto out;
  33
  34         res->bitmap[0] = res->bitmap[1] = 0;
  35         res->status = htonl(NFS4ERR_BADHANDLE);
  36
  37         dprintk_rcu("NFS: GETATTR callback request from %s\n",
  38                 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
  39
  40         inode = nfs_delegation_find_inode(cps->clp, &args->fh);
  41         if (inode == NULL) {
  42                 trace_nfs4_cb_getattr(cps->clp, &args->fh, NULL,
  43                                 -ntohl(res->status));
  44                 goto out;
  45         }
  46         nfsi = NFS_I(inode);
  47         rcu_read_lock();
  48         delegation = rcu_dereference(nfsi->delegation);
  49         if (delegation == NULL || (delegation->type & FMODE_WRITE) == 0)
  50                 goto out_iput;
  51         res->size = i_size_read(inode);
  52         res->change_attr = delegation->change_attr;
  53         if (nfsi->nrequests != 0)
  54                 res->change_attr++;
  55         res->ctime = inode->i_ctime;
  56         res->mtime = inode->i_mtime;
  57         res->bitmap[0] = (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE) &
  58                 args->bitmap[0];
  59         res->bitmap[1] = (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY) &
  60                 args->bitmap[1];
  61         res->status = 0;
  62 out_iput:
  63         rcu_read_unlock();
  64         trace_nfs4_cb_getattr(cps->clp, &args->fh, inode, -ntohl(res->status));
  65         iput(inode);
  66 out:
  67         dprintk("%s: exit with status = %d\n", __func__, ntohl(res->status));
  68         return res->status;
  69 }
  70
  71 __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy,
  72                             struct cb_process_state *cps)
  73 {
  74         struct inode *inode;
  75         __be32 res;
  76
  77         res = htonl(NFS4ERR_OP_NOT_IN_SESSION);
  78         if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
  79                 goto out;
  80
  81         dprintk_rcu("NFS: RECALL callback request from %s\n",
  82                 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
  83
  84         res = htonl(NFS4ERR_BADHANDLE);
  85         inode = nfs_delegation_find_inode(cps->clp, &args->fh);
  86         if (inode == NULL) {
  87                 trace_nfs4_cb_recall(cps->clp, &args->fh, NULL,
  88                                 &args->stateid, -ntohl(res));
  89                 goto out;
  90         }
  91         /* Set up a helper thread to actually return the delegation */
  92         switch (nfs_async_inode_return_delegation(inode, &args->stateid)) {
  93         case 0:
  94                 res = 0;
  95                 break;
  96         case -ENOENT:
  97                 res = htonl(NFS4ERR_BAD_STATEID);
  98                 break;
  99         default:
 100                 res = htonl(NFS4ERR_RESOURCE);
 101         }
 102         trace_nfs4_cb_recall(cps->clp, &args->fh, inode,
 103                         &args->stateid, -ntohl(res));
 104         iput(inode);
 105 out:
 106         dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
 107         return res;
 108 }
 109
 110 #if defined(CONFIG_NFS_V4_1)
 111
 112 /*
 113  * Lookup a layout by filehandle.
 114  *
 115  * Note: gets a refcount on the layout hdr and on its respective inode.
 116  * Caller must put the layout hdr and the inode.
 117  *
 118  * TODO: keep track of all layouts (and delegations) in a hash table
 119  * hashed by filehandle.
 120  */
 121 static struct pnfs_layout_hdr * get_layout_by_fh_locked(struct nfs_client *clp,
 122                 struct nfs_fh *fh)
 123 {
 124         struct nfs_server *server;
 125         struct nfs_inode *nfsi;
 126         struct inode *ino;
 127         struct pnfs_layout_hdr *lo;
 128
 129 restart:
 130         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 131                 list_for_each_entry(lo, &server->layouts, plh_layouts) {
 132                         nfsi = NFS_I(lo->plh_inode);
 133                         if (nfs_compare_fh(fh, &nfsi->fh))
 134                                 continue;
 135                         if (nfsi->layout != lo)
 136                                 continue;
 137                         ino = igrab(lo->plh_inode);
 138                         if (!ino)
 139                                 break;
 140                         spin_lock(&ino->i_lock);
 141                         /* Is this layout in the process of being freed? */
 142                         if (nfsi->layout != lo) {
 143                                 spin_unlock(&ino->i_lock);
 144                                 iput(ino);
 145                                 goto restart;
 146                         }
 147                         pnfs_get_layout_hdr(lo);
 148                         spin_unlock(&ino->i_lock);
 149                         return lo;
 150                 }
 151         }
 152
 153         return NULL;
 154 }
 155
 156 static struct pnfs_layout_hdr * get_layout_by_fh(struct nfs_client *clp,
 157                 struct nfs_fh *fh)
 158 {
 159         struct pnfs_layout_hdr *lo;
 160
 161         spin_lock(&clp->cl_lock);
 162         rcu_read_lock();
 163         lo = get_layout_by_fh_locked(clp, fh);
 164         rcu_read_unlock();
 165         spin_unlock(&clp->cl_lock);
 166
 167         return lo;
 168 }
 169
 170 /*
 171  * Enforce RFC5661 section 12.5.5.2.1. (Layout Recall and Return Sequencing)
 172  */
 173 static u32 pnfs_check_callback_stateid(struct pnfs_layout_hdr *lo,
 174                                         const nfs4_stateid *new)
 175 {
 176         u32 oldseq, newseq;
 177
 178         /* Is the stateid still not initialised? */
 179         if (!pnfs_layout_is_valid(lo))
 180                 return NFS4ERR_DELAY;
 181
 182         /* Mismatched stateid? */
 183         if (!nfs4_stateid_match_other(&lo->plh_stateid, new))
 184                 return NFS4ERR_BAD_STATEID;
 185
 186         newseq = be32_to_cpu(new->seqid);
 187         /* Are we already in a layout recall situation? */
 188         if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags) &&
 189             lo->plh_return_seq != 0) {
 190                 if (newseq < lo->plh_return_seq)
 191                         return NFS4ERR_OLD_STATEID;
 192                 if (newseq > lo->plh_return_seq)
 193                         return NFS4ERR_DELAY;
 194                 goto out;
 195         }
 196
 197         /* Check that the stateid matches what we think it should be. */
 198         oldseq = be32_to_cpu(lo->plh_stateid.seqid);
 199         if (newseq > oldseq + 1)
 200                 return NFS4ERR_DELAY;
 201         /* Crazy server! */
 202         if (newseq <= oldseq)
 203                 return NFS4ERR_OLD_STATEID;
 204 out:
 205         return NFS_OK;
 206 }
 207
 208 static u32 initiate_file_draining(struct nfs_client *clp,
 209                                   struct cb_layoutrecallargs *args)
 210 {
 211         struct inode *ino;
 212         struct pnfs_layout_hdr *lo;
 213         u32 rv = NFS4ERR_NOMATCHING_LAYOUT;
 214         LIST_HEAD(free_me_list);
 215
 216         lo = get_layout_by_fh(clp, &args->cbl_fh);
 217         if (!lo) {
 218                 trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, NULL,
 219                                 &args->cbl_stateid, -rv);
 220                 goto out;
 221         }
 222
 223         ino = lo->plh_inode;
 224         pnfs_layoutcommit_inode(ino, false);
 225
 226
 227         spin_lock(&ino->i_lock);
 228         rv = pnfs_check_callback_stateid(lo, &args->cbl_stateid);
 229         if (rv != NFS_OK)
 230                 goto unlock;
 231         pnfs_set_layout_stateid(lo, &args->cbl_stateid, true);
 232
 233         /*
 234          * Enforce RFC5661 Section 12.5.5.2.1.5 (Bulk Recall and Return)
 235          */
 236         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
 237                 rv = NFS4ERR_DELAY;
 238                 goto unlock;
 239         }
 240
 241         if (pnfs_mark_matching_lsegs_return(lo, &free_me_list,
 242                                 &args->cbl_range,
 243                                 be32_to_cpu(args->cbl_stateid.seqid))) {
 244                 rv = NFS4_OK;
 245                 goto unlock;
 246         }
 247
 248         /* Embrace your forgetfulness! */
 249         rv = NFS4ERR_NOMATCHING_LAYOUT;
 250
 251         if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) {
 252                 NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo,
 253                         &args->cbl_range);
 254         }
 255 unlock:
 256         spin_unlock(&ino->i_lock);
 257         pnfs_free_lseg_list(&free_me_list);
 258         /* Free all lsegs that are attached to commit buckets */
 259         nfs_commit_inode(ino, 0);
 260         pnfs_put_layout_hdr(lo);
 261         trace_nfs4_cb_layoutrecall_file(clp, &args->cbl_fh, ino,
 262                         &args->cbl_stateid, -rv);
 263         iput(ino);
 264 out:
 265         return rv;
 266 }
 267
 268 static u32 initiate_bulk_draining(struct nfs_client *clp,
 269                                   struct cb_layoutrecallargs *args)
 270 {
 271         int stat;
 272
 273         if (args->cbl_recall_type == RETURN_FSID)
 274                 stat = pnfs_destroy_layouts_byfsid(clp, &args->cbl_fsid, true);
 275         else
 276                 stat = pnfs_destroy_layouts_byclid(clp, true);
 277         if (stat != 0)
 278                 return NFS4ERR_DELAY;
 279         return NFS4ERR_NOMATCHING_LAYOUT;
 280 }
 281
 282 static u32 do_callback_layoutrecall(struct nfs_client *clp,
 283                                     struct cb_layoutrecallargs *args)
 284 {
 285         u32 res;
 286
 287         dprintk("%s enter, type=%i\n", __func__, args->cbl_recall_type);
 288         if (args->cbl_recall_type == RETURN_FILE)
 289                 res = initiate_file_draining(clp, args);
 290         else
 291                 res = initiate_bulk_draining(clp, args);
 292         dprintk("%s returning %i\n", __func__, res);
 293         return res;
 294
 295 }
 296
 297 __be32 nfs4_callback_layoutrecall(struct cb_layoutrecallargs *args,
 298                                   void *dummy, struct cb_process_state *cps)
 299 {
 300         u32 res;
 301
 302         dprintk("%s: -->\n", __func__);
 303
 304         if (cps->clp)
 305                 res = do_callback_layoutrecall(cps->clp, args);
 306         else
 307                 res = NFS4ERR_OP_NOT_IN_SESSION;
 308
 309         dprintk("%s: exit with status = %d\n", __func__, res);
 310         return cpu_to_be32(res);
 311 }
 312
 313 static void pnfs_recall_all_layouts(struct nfs_client *clp)
 314 {
 315         struct cb_layoutrecallargs args;
 316
 317         /* Pretend we got a CB_LAYOUTRECALL(ALL) */
 318         memset(&args, 0, sizeof(args));
 319         args.cbl_recall_type = RETURN_ALL;
 320         /* FIXME we ignore errors, what should we do? */
 321         do_callback_layoutrecall(clp, &args);
 322 }
 323
 324 __be32 nfs4_callback_devicenotify(struct cb_devicenotifyargs *args,
 325                                   void *dummy, struct cb_process_state *cps)
 326 {
 327         int i;
 328         __be32 res = 0;
 329         struct nfs_client *clp = cps->clp;
 330         struct nfs_server *server = NULL;
 331
 332         dprintk("%s: -->\n", __func__);
 333
 334         if (!clp) {
 335                 res = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
 336                 goto out;
 337         }
 338
 339         for (i = 0; i < args->ndevs; i++) {
 340                 struct cb_devicenotifyitem *dev = &args->devs[i];
 341
 342                 if (!server ||
 343                     server->pnfs_curr_ld->id != dev->cbd_layout_type) {
 344                         rcu_read_lock();
 345                         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
 346                                 if (server->pnfs_curr_ld &&
 347                                     server->pnfs_curr_ld->id == dev->cbd_layout_type) {
 348                                         rcu_read_unlock();
 349                                         goto found;
 350                                 }
 351                         rcu_read_unlock();
 352                         dprintk("%s: layout type %u not found\n",
 353                                 __func__, dev->cbd_layout_type);
 354                         continue;
 355                 }
 356
 357         found:
 358                 nfs4_delete_deviceid(server->pnfs_curr_ld, clp, &dev->cbd_dev_id);
 359         }
 360
 361 out:
 362         kfree(args->devs);
 363         dprintk("%s: exit with status = %u\n",
 364                 __func__, be32_to_cpu(res));
 365         return res;
 366 }
 367
 368 /*
 369  * Validate the sequenceID sent by the server.
 370  * Return success if the sequenceID is one more than what we last saw on
 371  * this slot, accounting for wraparound.  Increments the slot's sequence.
 372  *
 373  * We don't yet implement a duplicate request cache, instead we set the
 374  * back channel ca_maxresponsesize_cached to zero. This is OK for now
 375  * since we only currently implement idempotent callbacks anyway.
 376  *
 377  * We have a single slot backchannel at this time, so we don't bother
 378  * checking the used_slots bit array on the table.  The lower layer guarantees
 379  * a single outstanding callback request at a time.
 380  */
 381 static __be32
 382 validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot,
 383                 const struct cb_sequenceargs * args)
 384 {
 385         dprintk("%s enter. slotid %u seqid %u, slot table seqid: %u\n",
 386                 __func__, args->csa_slotid, args->csa_sequenceid, slot->seq_nr);
 387
 388         if (args->csa_slotid > tbl->server_highest_slotid)
 389                 return htonl(NFS4ERR_BADSLOT);
 390
 391         /* Replay */
 392         if (args->csa_sequenceid == slot->seq_nr) {
 393                 dprintk("%s seqid %u is a replay\n",
 394                         __func__, args->csa_sequenceid);
 395                 if (nfs4_test_locked_slot(tbl, slot->slot_nr))
 396                         return htonl(NFS4ERR_DELAY);
 397                 /* Signal process_op to set this error on next op */
 398                 if (args->csa_cachethis == 0)
 399                         return htonl(NFS4ERR_RETRY_UNCACHED_REP);
 400
 401                 /* Liar! We never allowed you to set csa_cachethis != 0 */
 402                 return htonl(NFS4ERR_SEQ_FALSE_RETRY);
 403         }
 404
 405         /* Wraparound */
 406         if (unlikely(slot->seq_nr == 0xFFFFFFFFU)) {
 407                 if (args->csa_sequenceid == 1)
 408                         return htonl(NFS4_OK);
 409         } else if (likely(args->csa_sequenceid == slot->seq_nr + 1))
 410                 return htonl(NFS4_OK);
 411
 412         /* Misordered request */
 413         return htonl(NFS4ERR_SEQ_MISORDERED);
 414 }
 415
 416 /*
 417  * For each referring call triple, check the session's slot table for
 418  * a match.  If the slot is in use and the sequence numbers match, the
 419  * client is still waiting for a response to the original request.
 420  */
 421 static bool referring_call_exists(struct nfs_client *clp,
 422                                   uint32_t nrclists,
 423                                   struct referring_call_list *rclists)
 424 {
 425         bool status = 0;
 426         int i, j;
 427         struct nfs4_session *session;
 428         struct nfs4_slot_table *tbl;
 429         struct referring_call_list *rclist;
 430         struct referring_call *ref;
 431
 432         /*
 433          * XXX When client trunking is implemented, this becomes
 434          * a session lookup from within the loop
 435          */
 436         session = clp->cl_session;
 437         tbl = &session->fc_slot_table;
 438
 439         for (i = 0; i < nrclists; i++) {
 440                 rclist = &rclists[i];
 441                 if (memcmp(session->sess_id.data,
 442                            rclist->rcl_sessionid.data,
 443                            NFS4_MAX_SESSIONID_LEN) != 0)
 444                         continue;
 445
 446                 for (j = 0; j < rclist->rcl_nrefcalls; j++) {
 447                         ref = &rclist->rcl_refcalls[j];
 448
 449                         dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u "
 450                                 "slotid %u\n", __func__,
 451                                 ((u32 *)&rclist->rcl_sessionid.data)[0],
 452                                 ((u32 *)&rclist->rcl_sessionid.data)[1],
 453                                 ((u32 *)&rclist->rcl_sessionid.data)[2],
 454                                 ((u32 *)&rclist->rcl_sessionid.data)[3],
 455                                 ref->rc_sequenceid, ref->rc_slotid);
 456
 457                         status = nfs4_slot_wait_on_seqid(tbl, ref->rc_slotid,
 458                                         ref->rc_sequenceid, HZ >> 1) < 0;
 459                         if (status)
 460                                 goto out;
 461                 }
 462         }
 463
 464 out:
 465         return status;
 466 }
 467
 468 __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 469                               struct cb_sequenceres *res,
 470                               struct cb_process_state *cps)
 471 {
 472         struct nfs4_slot_table *tbl;
 473         struct nfs4_slot *slot;
 474         struct nfs_client *clp;
 475         int i;
 476         __be32 status = htonl(NFS4ERR_BADSESSION);
 477
 478         clp = nfs4_find_client_sessionid(cps->net, args->csa_addr,
 479                                          &args->csa_sessionid, cps->minorversion);
 480         if (clp == NULL)
 481                 goto out;
 482
 483         if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
 484                 goto out;
 485
 486         tbl = &clp->cl_session->bc_slot_table;
 487
 488         /* Set up res before grabbing the spinlock */
 489         memcpy(&res->csr_sessionid, &args->csa_sessionid,
 490                sizeof(res->csr_sessionid));
 491         res->csr_sequenceid = args->csa_sequenceid;
 492         res->csr_slotid = args->csa_slotid;
 493
 494         spin_lock(&tbl->slot_tbl_lock);
 495         /* state manager is resetting the session */
 496         if (test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state)) {
 497                 status = htonl(NFS4ERR_DELAY);
 498                 /* Return NFS4ERR_BADSESSION if we're draining the session
 499                  * in order to reset it.
 500                  */
 501                 if (test_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state))
 502                         status = htonl(NFS4ERR_BADSESSION);
 503                 goto out_unlock;
 504         }
 505
 506         status = htonl(NFS4ERR_BADSLOT);
 507         slot = nfs4_lookup_slot(tbl, args->csa_slotid);
 508         if (IS_ERR(slot))
 509                 goto out_unlock;
 510
 511         res->csr_highestslotid = tbl->server_highest_slotid;
 512         res->csr_target_highestslotid = tbl->target_highest_slotid;
 513
 514         status = validate_seqid(tbl, slot, args);
 515         if (status)
 516                 goto out_unlock;
 517         if (!nfs4_try_to_lock_slot(tbl, slot)) {
 518                 status = htonl(NFS4ERR_DELAY);
 519                 goto out_unlock;
 520         }
 521         cps->slot = slot;
 522
 523         /* The ca_maxresponsesize_cached is 0 with no DRC */
 524         if (args->csa_cachethis != 0) {
 525                 status = htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
 526                 goto out_unlock;
 527         }
 528
 529         /*
 530          * Check for pending referring calls.  If a match is found, a
 531          * related callback was received before the response to the original
 532          * call.
 533          */
 534         if (referring_call_exists(clp, args->csa_nrclists, args->csa_rclists)) {
 535                 status = htonl(NFS4ERR_DELAY);
 536                 goto out_unlock;
 537         }
 538
 539         /*
 540          * RFC5661 20.9.3
 541          * If CB_SEQUENCE returns an error, then the state of the slot
 542          * (sequence ID, cached reply) MUST NOT change.
 543          */
 544         slot->seq_nr = args->csa_sequenceid;
 545 out_unlock:
 546         spin_unlock(&tbl->slot_tbl_lock);
 547
 548 out:
 549         cps->clp = clp; /* put in nfs4_callback_compound */
 550         for (i = 0; i < args->csa_nrclists; i++)
 551                 kfree(args->csa_rclists[i].rcl_refcalls);
 552         kfree(args->csa_rclists);
 553
 554         if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
 555                 cps->drc_status = status;
 556                 status = 0;
 557         } else
 558                 res->csr_status = status;
 559
 560         trace_nfs4_cb_sequence(args, res, status);
 561         dprintk("%s: exit with status = %d res->csr_status %d\n", __func__,
 562                 ntohl(status), ntohl(res->csr_status));
 563         return status;
 564 }
 565
 566 static bool
 567 validate_bitmap_values(unsigned long mask)
 568 {
 569         return (mask & ~RCA4_TYPE_MASK_ALL) == 0;
 570 }
 571
 572 __be32 nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy,
 573                                struct cb_process_state *cps)
 574 {
 575         __be32 status;
 576         fmode_t flags = 0;
 577
 578         status = cpu_to_be32(NFS4ERR_OP_NOT_IN_SESSION);
 579         if (!cps->clp) /* set in cb_sequence */
 580                 goto out;
 581
 582         dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
 583                 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
 584
 585         status = cpu_to_be32(NFS4ERR_INVAL);
 586         if (!validate_bitmap_values(args->craa_type_mask))
 587                 goto out;
 588
 589         status = cpu_to_be32(NFS4_OK);
 590         if (test_bit(RCA4_TYPE_MASK_RDATA_DLG, (const unsigned long *)
 591                      &args->craa_type_mask))
 592                 flags = FMODE_READ;
 593         if (test_bit(RCA4_TYPE_MASK_WDATA_DLG, (const unsigned long *)
 594                      &args->craa_type_mask))
 595                 flags |= FMODE_WRITE;
 596         if (test_bit(RCA4_TYPE_MASK_FILE_LAYOUT, (const unsigned long *)
 597                      &args->craa_type_mask))
 598                 pnfs_recall_all_layouts(cps->clp);
 599         if (flags)
 600                 nfs_expire_unused_delegation_types(cps->clp, flags);
 601 out:
 602         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 603         return status;
 604 }
 605
 606 /* Reduce the fore channel's max_slots to the target value */
 607 __be32 nfs4_callback_recallslot(struct cb_recallslotargs *args, void *dummy,
 608                                 struct cb_process_state *cps)
 609 {
 610         struct nfs4_slot_table *fc_tbl;
 611         __be32 status;
 612
 613         status = htonl(NFS4ERR_OP_NOT_IN_SESSION);
 614         if (!cps->clp) /* set in cb_sequence */
 615                 goto out;
 616
 617         dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target highest slotid %u\n",
 618                 rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
 619                 args->crsa_target_highest_slotid);
 620
 621         fc_tbl = &cps->clp->cl_session->fc_slot_table;
 622
 623         status = htonl(NFS4_OK);
 624
 625         nfs41_set_target_slotid(fc_tbl, args->crsa_target_highest_slotid);
 626         nfs41_notify_server(cps->clp);
 627 out:
 628         dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
 629         return status;
 630 }
 631 #endif /* CONFIG_NFS_V4_1 */