fs/nfsd/nfs4callback.c

   1 /*
   2  *  Copyright (c) 2001 The Regents of the University of Michigan.
   3  *  All rights reserved.
   4  *
   5  *  Kendrick Smith <kmsmith@umich.edu>
   6  *  Andy Adamson <andros@umich.edu>
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions
  10  *  are met:
  11  *
  12  *  1. Redistributions of source code must retain the above copyright
  13  *     notice, this list of conditions and the following disclaimer.
  14  *  2. Redistributions in binary form must reproduce the above copyright
  15  *     notice, this list of conditions and the following disclaimer in the
  16  *     documentation and/or other materials provided with the distribution.
  17  *  3. Neither the name of the University nor the names of its
  18  *     contributors may be used to endorse or promote products derived
  19  *     from this software without specific prior written permission.
  20  *
  21  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  22  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  29  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  31  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/xprt.h>
  36 #include <linux/sunrpc/svc_xprt.h>
  37 #include <linux/slab.h>
  38 #include "nfsd.h"
  39 #include "state.h"
  40 #include "netns.h"
  41 #include "xdr4cb.h"
  42
  43 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  44
  45 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  46
  47 #define NFSPROC4_CB_NULL 0
  48 #define NFSPROC4_CB_COMPOUND 1
  49
  50 /* Index of predefined Linux callback client operations */
  51
  52 struct nfs4_cb_compound_hdr {
  53         /* args */
  54         u32             ident;  /* minorversion 0 only */
  55         u32             nops;
  56         __be32          *nops_p;
  57         u32             minorversion;
  58         /* res */
  59         int             status;
  60 };
  61
  62 /*
  63  * Handle decode buffer overflows out-of-line.
  64  */
  65 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  66 {
  67         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  68                 "Remaining buffer length is %tu words.\n",
  69                 func, xdr->end - xdr->p);
  70 }
  71
  72 static __be32 *xdr_encode_empty_array(__be32 *p)
  73 {
  74         *p++ = xdr_zero;
  75         return p;
  76 }
  77
  78 /*
  79  * Encode/decode NFSv4 CB basic data types
  80  *
  81  * Basic NFSv4 callback data types are defined in section 15 of RFC
  82  * 3530: "Network File System (NFS) version 4 Protocol" and section
  83  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
  84  * 1 Protocol"
  85  */
  86
  87 /*
  88  *      nfs_cb_opnum4
  89  *
  90  *      enum nfs_cb_opnum4 {
  91  *              OP_CB_GETATTR           = 3,
  92  *                ...
  93  *      };
  94  */
  95 enum nfs_cb_opnum4 {
  96         OP_CB_GETATTR                   = 3,
  97         OP_CB_RECALL                    = 4,
  98         OP_CB_LAYOUTRECALL              = 5,
  99         OP_CB_NOTIFY                    = 6,
 100         OP_CB_PUSH_DELEG                = 7,
 101         OP_CB_RECALL_ANY                = 8,
 102         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 103         OP_CB_RECALL_SLOT               = 10,
 104         OP_CB_SEQUENCE                  = 11,
 105         OP_CB_WANTS_CANCELLED           = 12,
 106         OP_CB_NOTIFY_LOCK               = 13,
 107         OP_CB_NOTIFY_DEVICEID           = 14,
 108         OP_CB_ILLEGAL                   = 10044
 109 };
 110
 111 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 112 {
 113         __be32 *p;
 114
 115         p = xdr_reserve_space(xdr, 4);
 116         *p = cpu_to_be32(op);
 117 }
 118
 119 /*
 120  * nfs_fh4
 121  *
 122  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 123  */
 124 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 125 {
 126         u32 length = fh->fh_size;
 127         __be32 *p;
 128
 129         BUG_ON(length > NFS4_FHSIZE);
 130         p = xdr_reserve_space(xdr, 4 + length);
 131         xdr_encode_opaque(p, &fh->fh_base, length);
 132 }
 133
 134 /*
 135  * stateid4
 136  *
 137  *      struct stateid4 {
 138  *              uint32_t        seqid;
 139  *              opaque          other[12];
 140  *      };
 141  */
 142 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 143 {
 144         __be32 *p;
 145
 146         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 147         *p++ = cpu_to_be32(sid->si_generation);
 148         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 149 }
 150
 151 /*
 152  * sessionid4
 153  *
 154  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 155  */
 156 static void encode_sessionid4(struct xdr_stream *xdr,
 157                               const struct nfsd4_session *session)
 158 {
 159         __be32 *p;
 160
 161         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 162         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 163                                         NFS4_MAX_SESSIONID_LEN);
 164 }
 165
 166 /*
 167  * nfsstat4
 168  */
 169 static const struct {
 170         int stat;
 171         int errno;
 172 } nfs_cb_errtbl[] = {
 173         { NFS4_OK,              0               },
 174         { NFS4ERR_PERM,         -EPERM          },
 175         { NFS4ERR_NOENT,        -ENOENT         },
 176         { NFS4ERR_IO,           -EIO            },
 177         { NFS4ERR_NXIO,         -ENXIO          },
 178         { NFS4ERR_ACCESS,       -EACCES         },
 179         { NFS4ERR_EXIST,        -EEXIST         },
 180         { NFS4ERR_XDEV,         -EXDEV          },
 181         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 182         { NFS4ERR_ISDIR,        -EISDIR         },
 183         { NFS4ERR_INVAL,        -EINVAL         },
 184         { NFS4ERR_FBIG,         -EFBIG          },
 185         { NFS4ERR_NOSPC,        -ENOSPC         },
 186         { NFS4ERR_ROFS,         -EROFS          },
 187         { NFS4ERR_MLINK,        -EMLINK         },
 188         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 189         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 190         { NFS4ERR_DQUOT,        -EDQUOT         },
 191         { NFS4ERR_STALE,        -ESTALE         },
 192         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 193         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 194         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 195         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 196         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 197         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 198         { NFS4ERR_LOCKED,       -EAGAIN         },
 199         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 200         { NFS4ERR_SYMLINK,      -ELOOP          },
 201         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 202         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 203         { -1,                   -EIO            }
 204 };
 205
 206 /*
 207  * If we cannot translate the error, the recovery routines should
 208  * handle it.
 209  *
 210  * Note: remaining NFSv4 error codes have values > 10000, so should
 211  * not conflict with native Linux error codes.
 212  */
 213 static int nfs_cb_stat_to_errno(int status)
 214 {
 215         int i;
 216
 217         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 218                 if (nfs_cb_errtbl[i].stat == status)
 219                         return nfs_cb_errtbl[i].errno;
 220         }
 221
 222         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 223         return -status;
 224 }
 225
 226 static int decode_cb_op_status(struct xdr_stream *xdr,
 227                                enum nfs_cb_opnum4 expected, int *status)
 228 {
 229         __be32 *p;
 230         u32 op;
 231
 232         p = xdr_inline_decode(xdr, 4 + 4);
 233         if (unlikely(p == NULL))
 234                 goto out_overflow;
 235         op = be32_to_cpup(p++);
 236         if (unlikely(op != expected))
 237                 goto out_unexpected;
 238         *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 239         return 0;
 240 out_overflow:
 241         print_overflow_msg(__func__, xdr);
 242         return -EIO;
 243 out_unexpected:
 244         dprintk("NFSD: Callback server returned operation %d but "
 245                 "we issued a request for %d\n", op, expected);
 246         return -EIO;
 247 }
 248
 249 /*
 250  * CB_COMPOUND4args
 251  *
 252  *      struct CB_COMPOUND4args {
 253  *              utf8str_cs      tag;
 254  *              uint32_t        minorversion;
 255  *              uint32_t        callback_ident;
 256  *              nfs_cb_argop4   argarray<>;
 257  *      };
 258 */
 259 static void encode_cb_compound4args(struct xdr_stream *xdr,
 260                                     struct nfs4_cb_compound_hdr *hdr)
 261 {
 262         __be32 * p;
 263
 264         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 265         p = xdr_encode_empty_array(p);          /* empty tag */
 266         *p++ = cpu_to_be32(hdr->minorversion);
 267         *p++ = cpu_to_be32(hdr->ident);
 268
 269         hdr->nops_p = p;
 270         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 271 }
 272
 273 /*
 274  * Update argarray element count
 275  */
 276 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 277 {
 278         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 279         *hdr->nops_p = cpu_to_be32(hdr->nops);
 280 }
 281
 282 /*
 283  * CB_COMPOUND4res
 284  *
 285  *      struct CB_COMPOUND4res {
 286  *              nfsstat4        status;
 287  *              utf8str_cs      tag;
 288  *              nfs_cb_resop4   resarray<>;
 289  *      };
 290  */
 291 static int decode_cb_compound4res(struct xdr_stream *xdr,
 292                                   struct nfs4_cb_compound_hdr *hdr)
 293 {
 294         u32 length;
 295         __be32 *p;
 296
 297         p = xdr_inline_decode(xdr, 4 + 4);
 298         if (unlikely(p == NULL))
 299                 goto out_overflow;
 300         hdr->status = be32_to_cpup(p++);
 301         /* Ignore the tag */
 302         length = be32_to_cpup(p++);
 303         p = xdr_inline_decode(xdr, length + 4);
 304         if (unlikely(p == NULL))
 305                 goto out_overflow;
 306         p += XDR_QUADLEN(length);
 307         hdr->nops = be32_to_cpup(p);
 308         return 0;
 309 out_overflow:
 310         print_overflow_msg(__func__, xdr);
 311         return -EIO;
 312 }
 313
 314 /*
 315  * CB_RECALL4args
 316  *
 317  *      struct CB_RECALL4args {
 318  *              stateid4        stateid;
 319  *              bool            truncate;
 320  *              nfs_fh4         fh;
 321  *      };
 322  */
 323 static void encode_cb_recall4args(struct xdr_stream *xdr,
 324                                   const struct nfs4_delegation *dp,
 325                                   struct nfs4_cb_compound_hdr *hdr)
 326 {
 327         __be32 *p;
 328
 329         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 330         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 331
 332         p = xdr_reserve_space(xdr, 4);
 333         *p++ = xdr_zero;                        /* truncate */
 334
 335         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 336
 337         hdr->nops++;
 338 }
 339
 340 /*
 341  * CB_SEQUENCE4args
 342  *
 343  *      struct CB_SEQUENCE4args {
 344  *              sessionid4              csa_sessionid;
 345  *              sequenceid4             csa_sequenceid;
 346  *              slotid4                 csa_slotid;
 347  *              slotid4                 csa_highest_slotid;
 348  *              bool                    csa_cachethis;
 349  *              referring_call_list4    csa_referring_call_lists<>;
 350  *      };
 351  */
 352 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 353                                     const struct nfsd4_callback *cb,
 354                                     struct nfs4_cb_compound_hdr *hdr)
 355 {
 356         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 357         __be32 *p;
 358
 359         if (hdr->minorversion == 0)
 360                 return;
 361
 362         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 363         encode_sessionid4(xdr, session);
 364
 365         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 366         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 367         *p++ = xdr_zero;                        /* csa_slotid */
 368         *p++ = xdr_zero;                        /* csa_highest_slotid */
 369         *p++ = xdr_zero;                        /* csa_cachethis */
 370         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 371
 372         hdr->nops++;
 373 }
 374
 375 /*
 376  * CB_SEQUENCE4resok
 377  *
 378  *      struct CB_SEQUENCE4resok {
 379  *              sessionid4      csr_sessionid;
 380  *              sequenceid4     csr_sequenceid;
 381  *              slotid4         csr_slotid;
 382  *              slotid4         csr_highest_slotid;
 383  *              slotid4         csr_target_highest_slotid;
 384  *      };
 385  *
 386  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 387  *      case NFS4_OK:
 388  *              CB_SEQUENCE4resok       csr_resok4;
 389  *      default:
 390  *              void;
 391  *      };
 392  *
 393  * Our current back channel implmentation supports a single backchannel
 394  * with a single slot.
 395  */
 396 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 397                                     struct nfsd4_callback *cb)
 398 {
 399         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 400         int status = -ESERVERFAULT;
 401         __be32 *p;
 402         u32 dummy;
 403
 404         /*
 405          * If the server returns different values for sessionID, slotID or
 406          * sequence number, the server is looney tunes.
 407          */
 408         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 409         if (unlikely(p == NULL))
 410                 goto out_overflow;
 411
 412         if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 413                 dprintk("NFS: %s Invalid session id\n", __func__);
 414                 goto out;
 415         }
 416         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 417
 418         dummy = be32_to_cpup(p++);
 419         if (dummy != session->se_cb_seq_nr) {
 420                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 421                 goto out;
 422         }
 423
 424         dummy = be32_to_cpup(p++);
 425         if (dummy != 0) {
 426                 dprintk("NFS: %s Invalid slotid\n", __func__);
 427                 goto out;
 428         }
 429
 430         /*
 431          * FIXME: process highest slotid and target highest slotid
 432          */
 433         status = 0;
 434 out:
 435         cb->cb_seq_status = status;
 436         return status;
 437 out_overflow:
 438         print_overflow_msg(__func__, xdr);
 439         status = -EIO;
 440         goto out;
 441 }
 442
 443 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 444                                   struct nfsd4_callback *cb)
 445 {
 446         int status;
 447
 448         if (cb->cb_clp->cl_minorversion == 0)
 449                 return 0;
 450
 451         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 452         if (unlikely(status || cb->cb_seq_status))
 453                 return status;
 454
 455         return decode_cb_sequence4resok(xdr, cb);
 456 }
 457
 458 /*
 459  * NFSv4.0 and NFSv4.1 XDR encode functions
 460  *
 461  * NFSv4.0 callback argument types are defined in section 15 of RFC
 462  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 463  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 464  * Protocol".
 465  */
 466
 467 /*
 468  * NB: Without this zero space reservation, callbacks over krb5p fail
 469  */
 470 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 471                                  const void *__unused)
 472 {
 473         xdr_reserve_space(xdr, 0);
 474 }
 475
 476 /*
 477  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 478  */
 479 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 480                                    const void *data)
 481 {
 482         const struct nfsd4_callback *cb = data;
 483         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 484         struct nfs4_cb_compound_hdr hdr = {
 485                 .ident = cb->cb_clp->cl_cb_ident,
 486                 .minorversion = cb->cb_clp->cl_minorversion,
 487         };
 488
 489         encode_cb_compound4args(xdr, &hdr);
 490         encode_cb_sequence4args(xdr, cb, &hdr);
 491         encode_cb_recall4args(xdr, dp, &hdr);
 492         encode_cb_nops(&hdr);
 493 }
 494
 495
 496 /*
 497  * NFSv4.0 and NFSv4.1 XDR decode functions
 498  *
 499  * NFSv4.0 callback result types are defined in section 15 of RFC
 500  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 501  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 502  * Protocol".
 503  */
 504
 505 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 506                                 void *__unused)
 507 {
 508         return 0;
 509 }
 510
 511 /*
 512  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 513  */
 514 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 515                                   struct xdr_stream *xdr,
 516                                   void *data)
 517 {
 518         struct nfsd4_callback *cb = data;
 519         struct nfs4_cb_compound_hdr hdr;
 520         int status;
 521
 522         status = decode_cb_compound4res(xdr, &hdr);
 523         if (unlikely(status))
 524                 return status;
 525
 526         if (cb != NULL) {
 527                 status = decode_cb_sequence4res(xdr, cb);
 528                 if (unlikely(status || cb->cb_seq_status))
 529                         return status;
 530         }
 531
 532         return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 533 }
 534
 535 #ifdef CONFIG_NFSD_PNFS
 536 /*
 537  * CB_LAYOUTRECALL4args
 538  *
 539  *      struct layoutrecall_file4 {
 540  *              nfs_fh4         lor_fh;
 541  *              offset4         lor_offset;
 542  *              length4         lor_length;
 543  *              stateid4        lor_stateid;
 544  *      };
 545  *
 546  *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 547  *      case LAYOUTRECALL4_FILE:
 548  *              layoutrecall_file4 lor_layout;
 549  *      case LAYOUTRECALL4_FSID:
 550  *              fsid4              lor_fsid;
 551  *      case LAYOUTRECALL4_ALL:
 552  *              void;
 553  *      };
 554  *
 555  *      struct CB_LAYOUTRECALL4args {
 556  *              layouttype4             clora_type;
 557  *              layoutiomode4           clora_iomode;
 558  *              bool                    clora_changed;
 559  *              layoutrecall4           clora_recall;
 560  *      };
 561  */
 562 static void encode_cb_layout4args(struct xdr_stream *xdr,
 563                                   const struct nfs4_layout_stateid *ls,
 564                                   struct nfs4_cb_compound_hdr *hdr)
 565 {
 566         __be32 *p;
 567
 568         BUG_ON(hdr->minorversion == 0);
 569
 570         p = xdr_reserve_space(xdr, 5 * 4);
 571         *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 572         *p++ = cpu_to_be32(ls->ls_layout_type);
 573         *p++ = cpu_to_be32(IOMODE_ANY);
 574         *p++ = cpu_to_be32(1);
 575         *p = cpu_to_be32(RETURN_FILE);
 576
 577         encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 578
 579         p = xdr_reserve_space(xdr, 2 * 8);
 580         p = xdr_encode_hyper(p, 0);
 581         xdr_encode_hyper(p, NFS4_MAX_UINT64);
 582
 583         encode_stateid4(xdr, &ls->ls_recall_sid);
 584
 585         hdr->nops++;
 586 }
 587
 588 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 589                                    struct xdr_stream *xdr,
 590                                    const void *data)
 591 {
 592         const struct nfsd4_callback *cb = data;
 593         const struct nfs4_layout_stateid *ls =
 594                 container_of(cb, struct nfs4_layout_stateid, ls_recall);
 595         struct nfs4_cb_compound_hdr hdr = {
 596                 .ident = 0,
 597                 .minorversion = cb->cb_clp->cl_minorversion,
 598         };
 599
 600         encode_cb_compound4args(xdr, &hdr);
 601         encode_cb_sequence4args(xdr, cb, &hdr);
 602         encode_cb_layout4args(xdr, ls, &hdr);
 603         encode_cb_nops(&hdr);
 604 }
 605
 606 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 607                                   struct xdr_stream *xdr,
 608                                   void *data)
 609 {
 610         struct nfsd4_callback *cb = data;
 611         struct nfs4_cb_compound_hdr hdr;
 612         int status;
 613
 614         status = decode_cb_compound4res(xdr, &hdr);
 615         if (unlikely(status))
 616                 return status;
 617
 618         if (cb) {
 619                 status = decode_cb_sequence4res(xdr, cb);
 620                 if (unlikely(status || cb->cb_seq_status))
 621                         return status;
 622         }
 623         return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 624 }
 625 #endif /* CONFIG_NFSD_PNFS */
 626
 627 static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
 628 {
 629         __be32  *p;
 630
 631         p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
 632         p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
 633         xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
 634 }
 635
 636 static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 637                                         struct xdr_stream *xdr,
 638                                         const void *data)
 639 {
 640         const struct nfsd4_callback *cb = data;
 641         const struct nfsd4_blocked_lock *nbl =
 642                 container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
 643         struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
 644         struct nfs4_cb_compound_hdr hdr = {
 645                 .ident = 0,
 646                 .minorversion = cb->cb_clp->cl_minorversion,
 647         };
 648
 649         __be32 *p;
 650
 651         BUG_ON(hdr.minorversion == 0);
 652
 653         encode_cb_compound4args(xdr, &hdr);
 654         encode_cb_sequence4args(xdr, cb, &hdr);
 655
 656         p = xdr_reserve_space(xdr, 4);
 657         *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
 658         encode_nfs_fh4(xdr, &nbl->nbl_fh);
 659         encode_stateowner(xdr, &lo->lo_owner);
 660         hdr.nops++;
 661
 662         encode_cb_nops(&hdr);
 663 }
 664
 665 static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 666                                         struct xdr_stream *xdr,
 667                                         void *data)
 668 {
 669         struct nfsd4_callback *cb = data;
 670         struct nfs4_cb_compound_hdr hdr;
 671         int status;
 672
 673         status = decode_cb_compound4res(xdr, &hdr);
 674         if (unlikely(status))
 675                 return status;
 676
 677         if (cb) {
 678                 status = decode_cb_sequence4res(xdr, cb);
 679                 if (unlikely(status || cb->cb_seq_status))
 680                         return status;
 681         }
 682         return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
 683 }
 684
 685 /*
 686  * RPC procedure tables
 687  */
 688 #define PROC(proc, call, argtype, restype)                              \
 689 [NFSPROC4_CLNT_##proc] = {                                              \
 690         .p_proc    = NFSPROC4_CB_##call,                                \
 691         .p_encode  = nfs4_xdr_enc_##argtype,            \
 692         .p_decode  = nfs4_xdr_dec_##restype,                            \
 693         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 694         .p_replen  = NFS4_dec_##restype##_sz,                           \
 695         .p_statidx = NFSPROC4_CB_##call,                                \
 696         .p_name    = #proc,                                             \
 697 }
 698
 699 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 700         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 701         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 702 #ifdef CONFIG_NFSD_PNFS
 703         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 704 #endif
 705         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 706 };
 707
 708 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 709 static const struct rpc_version nfs_cb_version4 = {
 710 /*
 711  * Note on the callback rpc program version number: despite language in rfc
 712  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 713  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 714  * in practice that appears to be what implementations use.  The section
 715  * 18.36.3 language is expected to be fixed in an erratum.
 716  */
 717         .number                 = 1,
 718         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 719         .procs                  = nfs4_cb_procedures,
 720         .counts                 = nfs4_cb_counts,
 721 };
 722
 723 static const struct rpc_version *nfs_cb_version[2] = {
 724         [1] = &nfs_cb_version4,
 725 };
 726
 727 static const struct rpc_program cb_program;
 728
 729 static struct rpc_stat cb_stats = {
 730         .program                = &cb_program
 731 };
 732
 733 #define NFS4_CALLBACK 0x40000000
 734 static const struct rpc_program cb_program = {
 735         .name                   = "nfs4_cb",
 736         .number                 = NFS4_CALLBACK,
 737         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 738         .version                = nfs_cb_version,
 739         .stats                  = &cb_stats,
 740         .pipe_dir_name          = "nfsd4_cb",
 741 };
 742
 743 static int max_cb_time(struct net *net)
 744 {
 745         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 746         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 747 }
 748
 749 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 750 {
 751         if (clp->cl_minorversion == 0) {
 752                 char *principal = clp->cl_cred.cr_targ_princ ?
 753                                         clp->cl_cred.cr_targ_princ : "nfs";
 754                 struct rpc_cred *cred;
 755
 756                 cred = rpc_lookup_machine_cred(principal);
 757                 if (!IS_ERR(cred))
 758                         get_rpccred(cred);
 759                 return cred;
 760         } else {
 761                 struct rpc_auth *auth = client->cl_auth;
 762                 struct auth_cred acred = {};
 763
 764                 acred.uid = ses->se_cb_sec.uid;
 765                 acred.gid = ses->se_cb_sec.gid;
 766                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
 767         }
 768 }
 769
 770 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 771 {
 772         int maxtime = max_cb_time(clp->net);
 773         struct rpc_timeout      timeparms = {
 774                 .to_initval     = maxtime,
 775                 .to_retries     = 0,
 776                 .to_maxval      = maxtime,
 777         };
 778         struct rpc_create_args args = {
 779                 .net            = clp->net,
 780                 .address        = (struct sockaddr *) &conn->cb_addr,
 781                 .addrsize       = conn->cb_addrlen,
 782                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 783                 .timeout        = &timeparms,
 784                 .program        = &cb_program,
 785                 .version        = 1,
 786                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 787         };
 788         struct rpc_clnt *client;
 789         struct rpc_cred *cred;
 790
 791         if (clp->cl_minorversion == 0) {
 792                 if (!clp->cl_cred.cr_principal &&
 793                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 794                         return -EINVAL;
 795                 args.client_name = clp->cl_cred.cr_principal;
 796                 args.prognumber = conn->cb_prog;
 797                 args.protocol = XPRT_TRANSPORT_TCP;
 798                 args.authflavor = clp->cl_cred.cr_flavor;
 799                 clp->cl_cb_ident = conn->cb_ident;
 800         } else {
 801                 if (!conn->cb_xprt)
 802                         return -EINVAL;
 803                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 804                 clp->cl_cb_session = ses;
 805                 args.bc_xprt = conn->cb_xprt;
 806                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 807                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 808                                 XPRT_TRANSPORT_BC;
 809                 args.authflavor = ses->se_cb_sec.flavor;
 810         }
 811         /* Create RPC client */
 812         client = rpc_create(&args);
 813         if (IS_ERR(client)) {
 814                 dprintk("NFSD: couldn't create callback client: %ld\n",
 815                         PTR_ERR(client));
 816                 return PTR_ERR(client);
 817         }
 818         cred = get_backchannel_cred(clp, client, ses);
 819         if (IS_ERR(cred)) {
 820                 rpc_shutdown_client(client);
 821                 return PTR_ERR(cred);
 822         }
 823         clp->cl_cb_client = client;
 824         clp->cl_cb_cred = cred;
 825         return 0;
 826 }
 827
 828 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 829 {
 830         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 831                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 832 }
 833
 834 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 835 {
 836         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 837                 return;
 838         clp->cl_cb_state = NFSD4_CB_DOWN;
 839         warn_no_callback_path(clp, reason);
 840 }
 841
 842 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 843 {
 844         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 845                 return;
 846         clp->cl_cb_state = NFSD4_CB_FAULT;
 847         warn_no_callback_path(clp, reason);
 848 }
 849
 850 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 851 {
 852         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 853
 854         if (task->tk_status)
 855                 nfsd4_mark_cb_down(clp, task->tk_status);
 856         else
 857                 clp->cl_cb_state = NFSD4_CB_UP;
 858 }
 859
 860 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 861         /* XXX: release method to ensure we set the cb channel down if
 862          * necessary on early failure? */
 863         .rpc_call_done = nfsd4_cb_probe_done,
 864 };
 865
 866 static struct workqueue_struct *callback_wq;
 867
 868 /*
 869  * Poke the callback thread to process any updates to the callback
 870  * parameters, and send a null probe.
 871  */
 872 void nfsd4_probe_callback(struct nfs4_client *clp)
 873 {
 874         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 875         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 876         nfsd4_run_cb(&clp->cl_cb_null);
 877 }
 878
 879 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 880 {
 881         nfsd4_probe_callback(clp);
 882         flush_workqueue(callback_wq);
 883 }
 884
 885 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 886 {
 887         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 888         spin_lock(&clp->cl_lock);
 889         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 890         spin_unlock(&clp->cl_lock);
 891 }
 892
 893 /*
 894  * There's currently a single callback channel slot.
 895  * If the slot is available, then mark it busy.  Otherwise, set the
 896  * thread for sleeping on the callback RPC wait queue.
 897  */
 898 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 899 {
 900         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 901                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 902                 /* Race breaker */
 903                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 904                         dprintk("%s slot is busy\n", __func__);
 905                         return false;
 906                 }
 907                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
 908         }
 909         return true;
 910 }
 911
 912 /*
 913  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 914  * slots, and mark callback channel down on communication errors.
 915  */
 916 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 917 {
 918         struct nfsd4_callback *cb = calldata;
 919         struct nfs4_client *clp = cb->cb_clp;
 920         u32 minorversion = clp->cl_minorversion;
 921
 922         /*
 923          * cb_seq_status is only set in decode_cb_sequence4res,
 924          * and so will remain 1 if an rpc level failure occurs.
 925          */
 926         cb->cb_seq_status = 1;
 927         cb->cb_status = 0;
 928         if (minorversion) {
 929                 if (!cb->cb_holds_slot && !nfsd41_cb_get_slot(clp, task))
 930                         return;
 931                 cb->cb_holds_slot = true;
 932         }
 933         rpc_call_start(task);
 934 }
 935
 936 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
 937 {
 938         struct nfs4_client *clp = cb->cb_clp;
 939         struct nfsd4_session *session = clp->cl_cb_session;
 940         bool ret = true;
 941
 942         if (!clp->cl_minorversion) {
 943                 /*
 944                  * If the backchannel connection was shut down while this
 945                  * task was queued, we need to resubmit it after setting up
 946                  * a new backchannel connection.
 947                  *
 948                  * Note that if we lost our callback connection permanently
 949                  * the submission code will error out, so we don't need to
 950                  * handle that case here.
 951                  */
 952                 if (task->tk_flags & RPC_TASK_KILLED)
 953                         goto need_restart;
 954
 955                 return true;
 956         }
 957
 958         if (!cb->cb_holds_slot)
 959                 goto need_restart;
 960
 961         switch (cb->cb_seq_status) {
 962         case 0:
 963                 /*
 964                  * No need for lock, access serialized in nfsd4_cb_prepare
 965                  *
 966                  * RFC5661 20.9.3
 967                  * If CB_SEQUENCE returns an error, then the state of the slot
 968                  * (sequence ID, cached reply) MUST NOT change.
 969                  */
 970                 ++session->se_cb_seq_nr;
 971                 break;
 972         case -ESERVERFAULT:
 973                 ++session->se_cb_seq_nr;
 974                 /* Fall through */
 975         case 1:
 976         case -NFS4ERR_BADSESSION:
 977                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
 978                 ret = false;
 979                 break;
 980         case -NFS4ERR_DELAY:
 981                 if (!rpc_restart_call(task))
 982                         goto out;
 983
 984                 rpc_delay(task, 2 * HZ);
 985                 return false;
 986         case -NFS4ERR_BADSLOT:
 987                 goto retry_nowait;
 988         case -NFS4ERR_SEQ_MISORDERED:
 989                 if (session->se_cb_seq_nr != 1) {
 990                         session->se_cb_seq_nr = 1;
 991                         goto retry_nowait;
 992                 }
 993                 break;
 994         default:
 995                 dprintk("%s: unprocessed error %d\n", __func__,
 996                         cb->cb_seq_status);
 997         }
 998
 999         cb->cb_holds_slot = false;
1000         clear_bit(0, &clp->cl_cb_slot_busy);
1001         rpc_wake_up_next(&clp->cl_cb_waitq);
1002         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1003                 clp->cl_cb_session->se_cb_seq_nr);
1004
1005         if (task->tk_flags & RPC_TASK_KILLED)
1006                 goto need_restart;
1007 out:
1008         return ret;
1009 retry_nowait:
1010         if (rpc_restart_call_prepare(task))
1011                 ret = false;
1012         goto out;
1013 need_restart:
1014         task->tk_status = 0;
1015         cb->cb_need_restart = true;
1016         return false;
1017 }
1018
1019 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1020 {
1021         struct nfsd4_callback *cb = calldata;
1022         struct nfs4_client *clp = cb->cb_clp;
1023
1024         dprintk("%s: minorversion=%d\n", __func__,
1025                 clp->cl_minorversion);
1026
1027         if (!nfsd4_cb_sequence_done(task, cb))
1028                 return;
1029
1030         if (cb->cb_status) {
1031                 WARN_ON_ONCE(task->tk_status);
1032                 task->tk_status = cb->cb_status;
1033         }
1034
1035         switch (cb->cb_ops->done(cb, task)) {
1036         case 0:
1037                 task->tk_status = 0;
1038                 rpc_restart_call_prepare(task);
1039                 return;
1040         case 1:
1041                 break;
1042         case -1:
1043                 /* Network partition? */
1044                 nfsd4_mark_cb_down(clp, task->tk_status);
1045                 break;
1046         default:
1047                 BUG();
1048         }
1049 }
1050
1051 static void nfsd4_cb_release(void *calldata)
1052 {
1053         struct nfsd4_callback *cb = calldata;
1054
1055         if (cb->cb_need_restart)
1056                 nfsd4_run_cb(cb);
1057         else
1058                 cb->cb_ops->release(cb);
1059
1060 }
1061
1062 static const struct rpc_call_ops nfsd4_cb_ops = {
1063         .rpc_call_prepare = nfsd4_cb_prepare,
1064         .rpc_call_done = nfsd4_cb_done,
1065         .rpc_release = nfsd4_cb_release,
1066 };
1067
1068 int nfsd4_create_callback_queue(void)
1069 {
1070         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1071         if (!callback_wq)
1072                 return -ENOMEM;
1073         return 0;
1074 }
1075
1076 void nfsd4_destroy_callback_queue(void)
1077 {
1078         destroy_workqueue(callback_wq);
1079 }
1080
1081 /* must be called under the state lock */
1082 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1083 {
1084         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1085         /*
1086          * Note this won't actually result in a null callback;
1087          * instead, nfsd4_run_cb_null() will detect the killed
1088          * client, destroy the rpc client, and stop:
1089          */
1090         nfsd4_run_cb(&clp->cl_cb_null);
1091         flush_workqueue(callback_wq);
1092 }
1093
1094 /* requires cl_lock: */
1095 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1096 {
1097         struct nfsd4_session *s;
1098         struct nfsd4_conn *c;
1099
1100         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1101                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1102                         if (c->cn_flags & NFS4_CDFC4_BACK)
1103                                 return c;
1104                 }
1105         }
1106         return NULL;
1107 }
1108
1109 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1110 {
1111         struct nfs4_cb_conn conn;
1112         struct nfs4_client *clp = cb->cb_clp;
1113         struct nfsd4_session *ses = NULL;
1114         struct nfsd4_conn *c;
1115         int err;
1116
1117         /*
1118          * This is either an update, or the client dying; in either case,
1119          * kill the old client:
1120          */
1121         if (clp->cl_cb_client) {
1122                 rpc_shutdown_client(clp->cl_cb_client);
1123                 clp->cl_cb_client = NULL;
1124                 put_rpccred(clp->cl_cb_cred);
1125                 clp->cl_cb_cred = NULL;
1126         }
1127         if (clp->cl_cb_conn.cb_xprt) {
1128                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1129                 clp->cl_cb_conn.cb_xprt = NULL;
1130         }
1131         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1132                 return;
1133         spin_lock(&clp->cl_lock);
1134         /*
1135          * Only serialized callback code is allowed to clear these
1136          * flags; main nfsd code can only set them:
1137          */
1138         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1139         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1140         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1141         c = __nfsd4_find_backchannel(clp);
1142         if (c) {
1143                 svc_xprt_get(c->cn_xprt);
1144                 conn.cb_xprt = c->cn_xprt;
1145                 ses = c->cn_session;
1146         }
1147         spin_unlock(&clp->cl_lock);
1148
1149         err = setup_callback_client(clp, &conn, ses);
1150         if (err) {
1151                 nfsd4_mark_cb_down(clp, err);
1152                 if (c)
1153                         svc_xprt_put(c->cn_xprt);
1154                 return;
1155         }
1156 }
1157
1158 static void
1159 nfsd4_run_cb_work(struct work_struct *work)
1160 {
1161         struct nfsd4_callback *cb =
1162                 container_of(work, struct nfsd4_callback, cb_work);
1163         struct nfs4_client *clp = cb->cb_clp;
1164         struct rpc_clnt *clnt;
1165
1166         if (cb->cb_need_restart) {
1167                 cb->cb_need_restart = false;
1168         } else {
1169                 if (cb->cb_ops && cb->cb_ops->prepare)
1170                         cb->cb_ops->prepare(cb);
1171         }
1172
1173         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1174                 nfsd4_process_cb_update(cb);
1175
1176         clnt = clp->cl_cb_client;
1177         if (!clnt) {
1178                 /* Callback channel broken, or client killed; give up: */
1179                 if (cb->cb_ops && cb->cb_ops->release)
1180                         cb->cb_ops->release(cb);
1181                 return;
1182         }
1183
1184         /*
1185          * Don't send probe messages for 4.1 or later.
1186          */
1187         if (!cb->cb_ops && clp->cl_minorversion) {
1188                 clp->cl_cb_state = NFSD4_CB_UP;
1189                 return;
1190         }
1191
1192         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1193         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1194                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1195 }
1196
1197 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1198                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1199 {
1200         cb->cb_clp = clp;
1201         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1202         cb->cb_msg.rpc_argp = cb;
1203         cb->cb_msg.rpc_resp = cb;
1204         cb->cb_ops = ops;
1205         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1206         cb->cb_seq_status = 1;
1207         cb->cb_status = 0;
1208         cb->cb_need_restart = false;
1209         cb->cb_holds_slot = false;
1210 }
1211
1212 void nfsd4_run_cb(struct nfsd4_callback *cb)
1213 {
1214         queue_work(callback_wq, &cb->cb_work);
1215 }