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 #include "xdr4.h"
  43
  44 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  45
  46 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  47
  48 #define NFSPROC4_CB_NULL 0
  49 #define NFSPROC4_CB_COMPOUND 1
  50
  51 /* Index of predefined Linux callback client operations */
  52
  53 struct nfs4_cb_compound_hdr {
  54         /* args */
  55         u32             ident;  /* minorversion 0 only */
  56         u32             nops;
  57         __be32          *nops_p;
  58         u32             minorversion;
  59         /* res */
  60         int             status;
  61 };
  62
  63 static __be32 *xdr_encode_empty_array(__be32 *p)
  64 {
  65         *p++ = xdr_zero;
  66         return p;
  67 }
  68
  69 /*
  70  * Encode/decode NFSv4 CB basic data types
  71  *
  72  * Basic NFSv4 callback data types are defined in section 15 of RFC
  73  * 3530: "Network File System (NFS) version 4 Protocol" and section
  74  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
  75  * 1 Protocol"
  76  */
  77
  78 /*
  79  *      nfs_cb_opnum4
  80  *
  81  *      enum nfs_cb_opnum4 {
  82  *              OP_CB_GETATTR           = 3,
  83  *                ...
  84  *      };
  85  */
  86 enum nfs_cb_opnum4 {
  87         OP_CB_GETATTR                   = 3,
  88         OP_CB_RECALL                    = 4,
  89         OP_CB_LAYOUTRECALL              = 5,
  90         OP_CB_NOTIFY                    = 6,
  91         OP_CB_PUSH_DELEG                = 7,
  92         OP_CB_RECALL_ANY                = 8,
  93         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
  94         OP_CB_RECALL_SLOT               = 10,
  95         OP_CB_SEQUENCE                  = 11,
  96         OP_CB_WANTS_CANCELLED           = 12,
  97         OP_CB_NOTIFY_LOCK               = 13,
  98         OP_CB_NOTIFY_DEVICEID           = 14,
  99         OP_CB_OFFLOAD                   = 15,
 100         OP_CB_ILLEGAL                   = 10044
 101 };
 102
 103 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 104 {
 105         __be32 *p;
 106
 107         p = xdr_reserve_space(xdr, 4);
 108         *p = cpu_to_be32(op);
 109 }
 110
 111 /*
 112  * nfs_fh4
 113  *
 114  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 115  */
 116 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 117 {
 118         u32 length = fh->fh_size;
 119         __be32 *p;
 120
 121         BUG_ON(length > NFS4_FHSIZE);
 122         p = xdr_reserve_space(xdr, 4 + length);
 123         xdr_encode_opaque(p, &fh->fh_base, length);
 124 }
 125
 126 /*
 127  * stateid4
 128  *
 129  *      struct stateid4 {
 130  *              uint32_t        seqid;
 131  *              opaque          other[12];
 132  *      };
 133  */
 134 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 135 {
 136         __be32 *p;
 137
 138         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 139         *p++ = cpu_to_be32(sid->si_generation);
 140         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 141 }
 142
 143 /*
 144  * sessionid4
 145  *
 146  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 147  */
 148 static void encode_sessionid4(struct xdr_stream *xdr,
 149                               const struct nfsd4_session *session)
 150 {
 151         __be32 *p;
 152
 153         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 154         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 155                                         NFS4_MAX_SESSIONID_LEN);
 156 }
 157
 158 /*
 159  * nfsstat4
 160  */
 161 static const struct {
 162         int stat;
 163         int errno;
 164 } nfs_cb_errtbl[] = {
 165         { NFS4_OK,              0               },
 166         { NFS4ERR_PERM,         -EPERM          },
 167         { NFS4ERR_NOENT,        -ENOENT         },
 168         { NFS4ERR_IO,           -EIO            },
 169         { NFS4ERR_NXIO,         -ENXIO          },
 170         { NFS4ERR_ACCESS,       -EACCES         },
 171         { NFS4ERR_EXIST,        -EEXIST         },
 172         { NFS4ERR_XDEV,         -EXDEV          },
 173         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 174         { NFS4ERR_ISDIR,        -EISDIR         },
 175         { NFS4ERR_INVAL,        -EINVAL         },
 176         { NFS4ERR_FBIG,         -EFBIG          },
 177         { NFS4ERR_NOSPC,        -ENOSPC         },
 178         { NFS4ERR_ROFS,         -EROFS          },
 179         { NFS4ERR_MLINK,        -EMLINK         },
 180         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 181         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 182         { NFS4ERR_DQUOT,        -EDQUOT         },
 183         { NFS4ERR_STALE,        -ESTALE         },
 184         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 185         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 186         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 187         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 188         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 189         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 190         { NFS4ERR_LOCKED,       -EAGAIN         },
 191         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 192         { NFS4ERR_SYMLINK,      -ELOOP          },
 193         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 194         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 195         { -1,                   -EIO            }
 196 };
 197
 198 /*
 199  * If we cannot translate the error, the recovery routines should
 200  * handle it.
 201  *
 202  * Note: remaining NFSv4 error codes have values > 10000, so should
 203  * not conflict with native Linux error codes.
 204  */
 205 static int nfs_cb_stat_to_errno(int status)
 206 {
 207         int i;
 208
 209         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 210                 if (nfs_cb_errtbl[i].stat == status)
 211                         return nfs_cb_errtbl[i].errno;
 212         }
 213
 214         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 215         return -status;
 216 }
 217
 218 static int decode_cb_op_status(struct xdr_stream *xdr,
 219                                enum nfs_cb_opnum4 expected, int *status)
 220 {
 221         __be32 *p;
 222         u32 op;
 223
 224         p = xdr_inline_decode(xdr, 4 + 4);
 225         if (unlikely(p == NULL))
 226                 goto out_overflow;
 227         op = be32_to_cpup(p++);
 228         if (unlikely(op != expected))
 229                 goto out_unexpected;
 230         *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 231         return 0;
 232 out_overflow:
 233         return -EIO;
 234 out_unexpected:
 235         dprintk("NFSD: Callback server returned operation %d but "
 236                 "we issued a request for %d\n", op, expected);
 237         return -EIO;
 238 }
 239
 240 /*
 241  * CB_COMPOUND4args
 242  *
 243  *      struct CB_COMPOUND4args {
 244  *              utf8str_cs      tag;
 245  *              uint32_t        minorversion;
 246  *              uint32_t        callback_ident;
 247  *              nfs_cb_argop4   argarray<>;
 248  *      };
 249 */
 250 static void encode_cb_compound4args(struct xdr_stream *xdr,
 251                                     struct nfs4_cb_compound_hdr *hdr)
 252 {
 253         __be32 * p;
 254
 255         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 256         p = xdr_encode_empty_array(p);          /* empty tag */
 257         *p++ = cpu_to_be32(hdr->minorversion);
 258         *p++ = cpu_to_be32(hdr->ident);
 259
 260         hdr->nops_p = p;
 261         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 262 }
 263
 264 /*
 265  * Update argarray element count
 266  */
 267 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 268 {
 269         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 270         *hdr->nops_p = cpu_to_be32(hdr->nops);
 271 }
 272
 273 /*
 274  * CB_COMPOUND4res
 275  *
 276  *      struct CB_COMPOUND4res {
 277  *              nfsstat4        status;
 278  *              utf8str_cs      tag;
 279  *              nfs_cb_resop4   resarray<>;
 280  *      };
 281  */
 282 static int decode_cb_compound4res(struct xdr_stream *xdr,
 283                                   struct nfs4_cb_compound_hdr *hdr)
 284 {
 285         u32 length;
 286         __be32 *p;
 287
 288         p = xdr_inline_decode(xdr, 4 + 4);
 289         if (unlikely(p == NULL))
 290                 goto out_overflow;
 291         hdr->status = be32_to_cpup(p++);
 292         /* Ignore the tag */
 293         length = be32_to_cpup(p++);
 294         p = xdr_inline_decode(xdr, length + 4);
 295         if (unlikely(p == NULL))
 296                 goto out_overflow;
 297         p += XDR_QUADLEN(length);
 298         hdr->nops = be32_to_cpup(p);
 299         return 0;
 300 out_overflow:
 301         return -EIO;
 302 }
 303
 304 /*
 305  * CB_RECALL4args
 306  *
 307  *      struct CB_RECALL4args {
 308  *              stateid4        stateid;
 309  *              bool            truncate;
 310  *              nfs_fh4         fh;
 311  *      };
 312  */
 313 static void encode_cb_recall4args(struct xdr_stream *xdr,
 314                                   const struct nfs4_delegation *dp,
 315                                   struct nfs4_cb_compound_hdr *hdr)
 316 {
 317         __be32 *p;
 318
 319         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 320         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 321
 322         p = xdr_reserve_space(xdr, 4);
 323         *p++ = xdr_zero;                        /* truncate */
 324
 325         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 326
 327         hdr->nops++;
 328 }
 329
 330 /*
 331  * CB_SEQUENCE4args
 332  *
 333  *      struct CB_SEQUENCE4args {
 334  *              sessionid4              csa_sessionid;
 335  *              sequenceid4             csa_sequenceid;
 336  *              slotid4                 csa_slotid;
 337  *              slotid4                 csa_highest_slotid;
 338  *              bool                    csa_cachethis;
 339  *              referring_call_list4    csa_referring_call_lists<>;
 340  *      };
 341  */
 342 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 343                                     const struct nfsd4_callback *cb,
 344                                     struct nfs4_cb_compound_hdr *hdr)
 345 {
 346         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 347         __be32 *p;
 348
 349         if (hdr->minorversion == 0)
 350                 return;
 351
 352         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 353         encode_sessionid4(xdr, session);
 354
 355         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 356         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 357         *p++ = xdr_zero;                        /* csa_slotid */
 358         *p++ = xdr_zero;                        /* csa_highest_slotid */
 359         *p++ = xdr_zero;                        /* csa_cachethis */
 360         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 361
 362         hdr->nops++;
 363 }
 364
 365 /*
 366  * CB_SEQUENCE4resok
 367  *
 368  *      struct CB_SEQUENCE4resok {
 369  *              sessionid4      csr_sessionid;
 370  *              sequenceid4     csr_sequenceid;
 371  *              slotid4         csr_slotid;
 372  *              slotid4         csr_highest_slotid;
 373  *              slotid4         csr_target_highest_slotid;
 374  *      };
 375  *
 376  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 377  *      case NFS4_OK:
 378  *              CB_SEQUENCE4resok       csr_resok4;
 379  *      default:
 380  *              void;
 381  *      };
 382  *
 383  * Our current back channel implmentation supports a single backchannel
 384  * with a single slot.
 385  */
 386 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 387                                     struct nfsd4_callback *cb)
 388 {
 389         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 390         int status = -ESERVERFAULT;
 391         __be32 *p;
 392         u32 dummy;
 393
 394         /*
 395          * If the server returns different values for sessionID, slotID or
 396          * sequence number, the server is looney tunes.
 397          */
 398         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 399         if (unlikely(p == NULL))
 400                 goto out_overflow;
 401
 402         if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 403                 dprintk("NFS: %s Invalid session id\n", __func__);
 404                 goto out;
 405         }
 406         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 407
 408         dummy = be32_to_cpup(p++);
 409         if (dummy != session->se_cb_seq_nr) {
 410                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 411                 goto out;
 412         }
 413
 414         dummy = be32_to_cpup(p++);
 415         if (dummy != 0) {
 416                 dprintk("NFS: %s Invalid slotid\n", __func__);
 417                 goto out;
 418         }
 419
 420         /*
 421          * FIXME: process highest slotid and target highest slotid
 422          */
 423         status = 0;
 424 out:
 425         cb->cb_seq_status = status;
 426         return status;
 427 out_overflow:
 428         status = -EIO;
 429         goto out;
 430 }
 431
 432 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 433                                   struct nfsd4_callback *cb)
 434 {
 435         int status;
 436
 437         if (cb->cb_clp->cl_minorversion == 0)
 438                 return 0;
 439
 440         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 441         if (unlikely(status || cb->cb_seq_status))
 442                 return status;
 443
 444         return decode_cb_sequence4resok(xdr, cb);
 445 }
 446
 447 /*
 448  * NFSv4.0 and NFSv4.1 XDR encode functions
 449  *
 450  * NFSv4.0 callback argument types are defined in section 15 of RFC
 451  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 452  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 453  * Protocol".
 454  */
 455
 456 /*
 457  * NB: Without this zero space reservation, callbacks over krb5p fail
 458  */
 459 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 460                                  const void *__unused)
 461 {
 462         xdr_reserve_space(xdr, 0);
 463 }
 464
 465 /*
 466  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 467  */
 468 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 469                                    const void *data)
 470 {
 471         const struct nfsd4_callback *cb = data;
 472         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 473         struct nfs4_cb_compound_hdr hdr = {
 474                 .ident = cb->cb_clp->cl_cb_ident,
 475                 .minorversion = cb->cb_clp->cl_minorversion,
 476         };
 477
 478         encode_cb_compound4args(xdr, &hdr);
 479         encode_cb_sequence4args(xdr, cb, &hdr);
 480         encode_cb_recall4args(xdr, dp, &hdr);
 481         encode_cb_nops(&hdr);
 482 }
 483
 484
 485 /*
 486  * NFSv4.0 and NFSv4.1 XDR decode functions
 487  *
 488  * NFSv4.0 callback result types are defined in section 15 of RFC
 489  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 490  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 491  * Protocol".
 492  */
 493
 494 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 495                                 void *__unused)
 496 {
 497         return 0;
 498 }
 499
 500 /*
 501  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 502  */
 503 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 504                                   struct xdr_stream *xdr,
 505                                   void *data)
 506 {
 507         struct nfsd4_callback *cb = data;
 508         struct nfs4_cb_compound_hdr hdr;
 509         int status;
 510
 511         status = decode_cb_compound4res(xdr, &hdr);
 512         if (unlikely(status))
 513                 return status;
 514
 515         status = decode_cb_sequence4res(xdr, cb);
 516         if (unlikely(status || cb->cb_seq_status))
 517                 return status;
 518
 519         return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 520 }
 521
 522 #ifdef CONFIG_NFSD_PNFS
 523 /*
 524  * CB_LAYOUTRECALL4args
 525  *
 526  *      struct layoutrecall_file4 {
 527  *              nfs_fh4         lor_fh;
 528  *              offset4         lor_offset;
 529  *              length4         lor_length;
 530  *              stateid4        lor_stateid;
 531  *      };
 532  *
 533  *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 534  *      case LAYOUTRECALL4_FILE:
 535  *              layoutrecall_file4 lor_layout;
 536  *      case LAYOUTRECALL4_FSID:
 537  *              fsid4              lor_fsid;
 538  *      case LAYOUTRECALL4_ALL:
 539  *              void;
 540  *      };
 541  *
 542  *      struct CB_LAYOUTRECALL4args {
 543  *              layouttype4             clora_type;
 544  *              layoutiomode4           clora_iomode;
 545  *              bool                    clora_changed;
 546  *              layoutrecall4           clora_recall;
 547  *      };
 548  */
 549 static void encode_cb_layout4args(struct xdr_stream *xdr,
 550                                   const struct nfs4_layout_stateid *ls,
 551                                   struct nfs4_cb_compound_hdr *hdr)
 552 {
 553         __be32 *p;
 554
 555         BUG_ON(hdr->minorversion == 0);
 556
 557         p = xdr_reserve_space(xdr, 5 * 4);
 558         *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 559         *p++ = cpu_to_be32(ls->ls_layout_type);
 560         *p++ = cpu_to_be32(IOMODE_ANY);
 561         *p++ = cpu_to_be32(1);
 562         *p = cpu_to_be32(RETURN_FILE);
 563
 564         encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 565
 566         p = xdr_reserve_space(xdr, 2 * 8);
 567         p = xdr_encode_hyper(p, 0);
 568         xdr_encode_hyper(p, NFS4_MAX_UINT64);
 569
 570         encode_stateid4(xdr, &ls->ls_recall_sid);
 571
 572         hdr->nops++;
 573 }
 574
 575 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 576                                    struct xdr_stream *xdr,
 577                                    const void *data)
 578 {
 579         const struct nfsd4_callback *cb = data;
 580         const struct nfs4_layout_stateid *ls =
 581                 container_of(cb, struct nfs4_layout_stateid, ls_recall);
 582         struct nfs4_cb_compound_hdr hdr = {
 583                 .ident = 0,
 584                 .minorversion = cb->cb_clp->cl_minorversion,
 585         };
 586
 587         encode_cb_compound4args(xdr, &hdr);
 588         encode_cb_sequence4args(xdr, cb, &hdr);
 589         encode_cb_layout4args(xdr, ls, &hdr);
 590         encode_cb_nops(&hdr);
 591 }
 592
 593 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 594                                   struct xdr_stream *xdr,
 595                                   void *data)
 596 {
 597         struct nfsd4_callback *cb = data;
 598         struct nfs4_cb_compound_hdr hdr;
 599         int status;
 600
 601         status = decode_cb_compound4res(xdr, &hdr);
 602         if (unlikely(status))
 603                 return status;
 604
 605         status = decode_cb_sequence4res(xdr, cb);
 606         if (unlikely(status || cb->cb_seq_status))
 607                 return status;
 608
 609         return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 610 }
 611 #endif /* CONFIG_NFSD_PNFS */
 612
 613 static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
 614 {
 615         __be32  *p;
 616
 617         p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
 618         p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
 619         xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
 620 }
 621
 622 static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 623                                         struct xdr_stream *xdr,
 624                                         const void *data)
 625 {
 626         const struct nfsd4_callback *cb = data;
 627         const struct nfsd4_blocked_lock *nbl =
 628                 container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
 629         struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
 630         struct nfs4_cb_compound_hdr hdr = {
 631                 .ident = 0,
 632                 .minorversion = cb->cb_clp->cl_minorversion,
 633         };
 634
 635         __be32 *p;
 636
 637         BUG_ON(hdr.minorversion == 0);
 638
 639         encode_cb_compound4args(xdr, &hdr);
 640         encode_cb_sequence4args(xdr, cb, &hdr);
 641
 642         p = xdr_reserve_space(xdr, 4);
 643         *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
 644         encode_nfs_fh4(xdr, &nbl->nbl_fh);
 645         encode_stateowner(xdr, &lo->lo_owner);
 646         hdr.nops++;
 647
 648         encode_cb_nops(&hdr);
 649 }
 650
 651 static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 652                                         struct xdr_stream *xdr,
 653                                         void *data)
 654 {
 655         struct nfsd4_callback *cb = data;
 656         struct nfs4_cb_compound_hdr hdr;
 657         int status;
 658
 659         status = decode_cb_compound4res(xdr, &hdr);
 660         if (unlikely(status))
 661                 return status;
 662
 663         status = decode_cb_sequence4res(xdr, cb);
 664         if (unlikely(status || cb->cb_seq_status))
 665                 return status;
 666
 667         return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
 668 }
 669
 670 /*
 671  * struct write_response4 {
 672  *      stateid4        wr_callback_id<1>;
 673  *      length4         wr_count;
 674  *      stable_how4     wr_committed;
 675  *      verifier4       wr_writeverf;
 676  * };
 677  * union offload_info4 switch (nfsstat4 coa_status) {
 678  *      case NFS4_OK:
 679  *              write_response4 coa_resok4;
 680  *      default:
 681  *      length4         coa_bytes_copied;
 682  * };
 683  * struct CB_OFFLOAD4args {
 684  *      nfs_fh4         coa_fh;
 685  *      stateid4        coa_stateid;
 686  *      offload_info4   coa_offload_info;
 687  * };
 688  */
 689 static void encode_offload_info4(struct xdr_stream *xdr,
 690                                  __be32 nfserr,
 691                                  const struct nfsd4_copy *cp)
 692 {
 693         __be32 *p;
 694
 695         p = xdr_reserve_space(xdr, 4);
 696         *p++ = nfserr;
 697         if (!nfserr) {
 698                 p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
 699                 p = xdr_encode_empty_array(p);
 700                 p = xdr_encode_hyper(p, cp->cp_res.wr_bytes_written);
 701                 *p++ = cpu_to_be32(cp->cp_res.wr_stable_how);
 702                 p = xdr_encode_opaque_fixed(p, cp->cp_res.wr_verifier.data,
 703                                             NFS4_VERIFIER_SIZE);
 704         } else {
 705                 p = xdr_reserve_space(xdr, 8);
 706                 /* We always return success if bytes were written */
 707                 p = xdr_encode_hyper(p, 0);
 708         }
 709 }
 710
 711 static void encode_cb_offload4args(struct xdr_stream *xdr,
 712                                    __be32 nfserr,
 713                                    const struct knfsd_fh *fh,
 714                                    const struct nfsd4_copy *cp,
 715                                    struct nfs4_cb_compound_hdr *hdr)
 716 {
 717         __be32 *p;
 718
 719         p = xdr_reserve_space(xdr, 4);
 720         *p++ = cpu_to_be32(OP_CB_OFFLOAD);
 721         encode_nfs_fh4(xdr, fh);
 722         encode_stateid4(xdr, &cp->cp_res.cb_stateid);
 723         encode_offload_info4(xdr, nfserr, cp);
 724
 725         hdr->nops++;
 726 }
 727
 728 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 729                                     struct xdr_stream *xdr,
 730                                     const void *data)
 731 {
 732         const struct nfsd4_callback *cb = data;
 733         const struct nfsd4_copy *cp =
 734                 container_of(cb, struct nfsd4_copy, cp_cb);
 735         struct nfs4_cb_compound_hdr hdr = {
 736                 .ident = 0,
 737                 .minorversion = cb->cb_clp->cl_minorversion,
 738         };
 739
 740         encode_cb_compound4args(xdr, &hdr);
 741         encode_cb_sequence4args(xdr, cb, &hdr);
 742         encode_cb_offload4args(xdr, cp->nfserr, &cp->fh, cp, &hdr);
 743         encode_cb_nops(&hdr);
 744 }
 745
 746 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 747                                    struct xdr_stream *xdr,
 748                                    void *data)
 749 {
 750         struct nfsd4_callback *cb = data;
 751         struct nfs4_cb_compound_hdr hdr;
 752         int status;
 753
 754         status = decode_cb_compound4res(xdr, &hdr);
 755         if (unlikely(status))
 756                 return status;
 757
 758         status = decode_cb_sequence4res(xdr, cb);
 759         if (unlikely(status || cb->cb_seq_status))
 760                 return status;
 761
 762         return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 763 }
 764 /*
 765  * RPC procedure tables
 766  */
 767 #define PROC(proc, call, argtype, restype)                              \
 768 [NFSPROC4_CLNT_##proc] = {                                              \
 769         .p_proc    = NFSPROC4_CB_##call,                                \
 770         .p_encode  = nfs4_xdr_enc_##argtype,            \
 771         .p_decode  = nfs4_xdr_dec_##restype,                            \
 772         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 773         .p_replen  = NFS4_dec_##restype##_sz,                           \
 774         .p_statidx = NFSPROC4_CB_##call,                                \
 775         .p_name    = #proc,                                             \
 776 }
 777
 778 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 779         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 780         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 781 #ifdef CONFIG_NFSD_PNFS
 782         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 783 #endif
 784         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 785         PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 786 };
 787
 788 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 789 static const struct rpc_version nfs_cb_version4 = {
 790 /*
 791  * Note on the callback rpc program version number: despite language in rfc
 792  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 793  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 794  * in practice that appears to be what implementations use.  The section
 795  * 18.36.3 language is expected to be fixed in an erratum.
 796  */
 797         .number                 = 1,
 798         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 799         .procs                  = nfs4_cb_procedures,
 800         .counts                 = nfs4_cb_counts,
 801 };
 802
 803 static const struct rpc_version *nfs_cb_version[2] = {
 804         [1] = &nfs_cb_version4,
 805 };
 806
 807 static const struct rpc_program cb_program;
 808
 809 static struct rpc_stat cb_stats = {
 810         .program                = &cb_program
 811 };
 812
 813 #define NFS4_CALLBACK 0x40000000
 814 static const struct rpc_program cb_program = {
 815         .name                   = "nfs4_cb",
 816         .number                 = NFS4_CALLBACK,
 817         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 818         .version                = nfs_cb_version,
 819         .stats                  = &cb_stats,
 820         .pipe_dir_name          = "nfsd4_cb",
 821 };
 822
 823 static int max_cb_time(struct net *net)
 824 {
 825         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 826         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 827 }
 828
 829 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 830 {
 831         if (clp->cl_minorversion == 0) {
 832                 client->cl_principal = clp->cl_cred.cr_targ_princ ?
 833                         clp->cl_cred.cr_targ_princ : "nfs";
 834
 835                 return get_cred(rpc_machine_cred());
 836         } else {
 837                 struct cred *kcred;
 838
 839                 kcred = prepare_kernel_cred(NULL);
 840                 if (!kcred)
 841                         return NULL;
 842
 843                 kcred->uid = ses->se_cb_sec.uid;
 844                 kcred->gid = ses->se_cb_sec.gid;
 845                 return kcred;
 846         }
 847 }
 848
 849 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 850 {
 851         int maxtime = max_cb_time(clp->net);
 852         struct rpc_timeout      timeparms = {
 853                 .to_initval     = maxtime,
 854                 .to_retries     = 0,
 855                 .to_maxval      = maxtime,
 856         };
 857         struct rpc_create_args args = {
 858                 .net            = clp->net,
 859                 .address        = (struct sockaddr *) &conn->cb_addr,
 860                 .addrsize       = conn->cb_addrlen,
 861                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 862                 .timeout        = &timeparms,
 863                 .program        = &cb_program,
 864                 .version        = 1,
 865                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 866                 .cred           = current_cred(),
 867         };
 868         struct rpc_clnt *client;
 869         const struct cred *cred;
 870
 871         if (clp->cl_minorversion == 0) {
 872                 if (!clp->cl_cred.cr_principal &&
 873                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 874                         return -EINVAL;
 875                 args.client_name = clp->cl_cred.cr_principal;
 876                 args.prognumber = conn->cb_prog;
 877                 args.protocol = XPRT_TRANSPORT_TCP;
 878                 args.authflavor = clp->cl_cred.cr_flavor;
 879                 clp->cl_cb_ident = conn->cb_ident;
 880         } else {
 881                 if (!conn->cb_xprt)
 882                         return -EINVAL;
 883                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 884                 clp->cl_cb_session = ses;
 885                 args.bc_xprt = conn->cb_xprt;
 886                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 887                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 888                                 XPRT_TRANSPORT_BC;
 889                 args.authflavor = ses->se_cb_sec.flavor;
 890         }
 891         /* Create RPC client */
 892         client = rpc_create(&args);
 893         if (IS_ERR(client)) {
 894                 dprintk("NFSD: couldn't create callback client: %ld\n",
 895                         PTR_ERR(client));
 896                 return PTR_ERR(client);
 897         }
 898         cred = get_backchannel_cred(clp, client, ses);
 899         if (!cred) {
 900                 rpc_shutdown_client(client);
 901                 return -ENOMEM;
 902         }
 903         clp->cl_cb_client = client;
 904         clp->cl_cb_cred = cred;
 905         return 0;
 906 }
 907
 908 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 909 {
 910         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 911                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 912 }
 913
 914 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 915 {
 916         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 917                 return;
 918         clp->cl_cb_state = NFSD4_CB_DOWN;
 919         warn_no_callback_path(clp, reason);
 920 }
 921
 922 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 923 {
 924         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 925                 return;
 926         clp->cl_cb_state = NFSD4_CB_FAULT;
 927         warn_no_callback_path(clp, reason);
 928 }
 929
 930 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 931 {
 932         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 933
 934         if (task->tk_status)
 935                 nfsd4_mark_cb_down(clp, task->tk_status);
 936         else
 937                 clp->cl_cb_state = NFSD4_CB_UP;
 938 }
 939
 940 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 941         /* XXX: release method to ensure we set the cb channel down if
 942          * necessary on early failure? */
 943         .rpc_call_done = nfsd4_cb_probe_done,
 944 };
 945
 946 static struct workqueue_struct *callback_wq;
 947
 948 /*
 949  * Poke the callback thread to process any updates to the callback
 950  * parameters, and send a null probe.
 951  */
 952 void nfsd4_probe_callback(struct nfs4_client *clp)
 953 {
 954         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 955         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 956         nfsd4_run_cb(&clp->cl_cb_null);
 957 }
 958
 959 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 960 {
 961         nfsd4_probe_callback(clp);
 962         flush_workqueue(callback_wq);
 963 }
 964
 965 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 966 {
 967         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 968         spin_lock(&clp->cl_lock);
 969         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 970         spin_unlock(&clp->cl_lock);
 971 }
 972
 973 /*
 974  * There's currently a single callback channel slot.
 975  * If the slot is available, then mark it busy.  Otherwise, set the
 976  * thread for sleeping on the callback RPC wait queue.
 977  */
 978 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 979 {
 980         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 981                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 982                 /* Race breaker */
 983                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 984                         dprintk("%s slot is busy\n", __func__);
 985                         return false;
 986                 }
 987                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
 988         }
 989         return true;
 990 }
 991
 992 /*
 993  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 994  * slots, and mark callback channel down on communication errors.
 995  */
 996 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 997 {
 998         struct nfsd4_callback *cb = calldata;
 999         struct nfs4_client *clp = cb->cb_clp;
1000         u32 minorversion = clp->cl_minorversion;
1001
1002         /*
1003          * cb_seq_status is only set in decode_cb_sequence4res,
1004          * and so will remain 1 if an rpc level failure occurs.
1005          */
1006         cb->cb_seq_status = 1;
1007         cb->cb_status = 0;
1008         if (minorversion) {
1009                 if (!cb->cb_holds_slot && !nfsd41_cb_get_slot(clp, task))
1010                         return;
1011                 cb->cb_holds_slot = true;
1012         }
1013         rpc_call_start(task);
1014 }
1015
1016 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1017 {
1018         struct nfs4_client *clp = cb->cb_clp;
1019         struct nfsd4_session *session = clp->cl_cb_session;
1020         bool ret = true;
1021
1022         if (!clp->cl_minorversion) {
1023                 /*
1024                  * If the backchannel connection was shut down while this
1025                  * task was queued, we need to resubmit it after setting up
1026                  * a new backchannel connection.
1027                  *
1028                  * Note that if we lost our callback connection permanently
1029                  * the submission code will error out, so we don't need to
1030                  * handle that case here.
1031                  */
1032                 if (RPC_SIGNALLED(task))
1033                         goto need_restart;
1034
1035                 return true;
1036         }
1037
1038         if (!cb->cb_holds_slot)
1039                 goto need_restart;
1040
1041         switch (cb->cb_seq_status) {
1042         case 0:
1043                 /*
1044                  * No need for lock, access serialized in nfsd4_cb_prepare
1045                  *
1046                  * RFC5661 20.9.3
1047                  * If CB_SEQUENCE returns an error, then the state of the slot
1048                  * (sequence ID, cached reply) MUST NOT change.
1049                  */
1050                 ++session->se_cb_seq_nr;
1051                 break;
1052         case -ESERVERFAULT:
1053                 ++session->se_cb_seq_nr;
1054                 /* Fall through */
1055         case 1:
1056         case -NFS4ERR_BADSESSION:
1057                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1058                 ret = false;
1059                 break;
1060         case -NFS4ERR_DELAY:
1061                 if (!rpc_restart_call(task))
1062                         goto out;
1063
1064                 rpc_delay(task, 2 * HZ);
1065                 return false;
1066         case -NFS4ERR_BADSLOT:
1067                 goto retry_nowait;
1068         case -NFS4ERR_SEQ_MISORDERED:
1069                 if (session->se_cb_seq_nr != 1) {
1070                         session->se_cb_seq_nr = 1;
1071                         goto retry_nowait;
1072                 }
1073                 break;
1074         default:
1075                 dprintk("%s: unprocessed error %d\n", __func__,
1076                         cb->cb_seq_status);
1077         }
1078
1079         cb->cb_holds_slot = false;
1080         clear_bit(0, &clp->cl_cb_slot_busy);
1081         rpc_wake_up_next(&clp->cl_cb_waitq);
1082         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1083                 clp->cl_cb_session->se_cb_seq_nr);
1084
1085         if (RPC_SIGNALLED(task))
1086                 goto need_restart;
1087 out:
1088         return ret;
1089 retry_nowait:
1090         if (rpc_restart_call_prepare(task))
1091                 ret = false;
1092         goto out;
1093 need_restart:
1094         task->tk_status = 0;
1095         cb->cb_need_restart = true;
1096         return false;
1097 }
1098
1099 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1100 {
1101         struct nfsd4_callback *cb = calldata;
1102         struct nfs4_client *clp = cb->cb_clp;
1103
1104         dprintk("%s: minorversion=%d\n", __func__,
1105                 clp->cl_minorversion);
1106
1107         if (!nfsd4_cb_sequence_done(task, cb))
1108                 return;
1109
1110         if (cb->cb_status) {
1111                 WARN_ON_ONCE(task->tk_status);
1112                 task->tk_status = cb->cb_status;
1113         }
1114
1115         switch (cb->cb_ops->done(cb, task)) {
1116         case 0:
1117                 task->tk_status = 0;
1118                 rpc_restart_call_prepare(task);
1119                 return;
1120         case 1:
1121                 switch (task->tk_status) {
1122                 case -EIO:
1123                 case -ETIMEDOUT:
1124                         nfsd4_mark_cb_down(clp, task->tk_status);
1125                 }
1126                 break;
1127         default:
1128                 BUG();
1129         }
1130 }
1131
1132 static void nfsd4_cb_release(void *calldata)
1133 {
1134         struct nfsd4_callback *cb = calldata;
1135
1136         if (cb->cb_need_restart)
1137                 nfsd4_run_cb(cb);
1138         else
1139                 cb->cb_ops->release(cb);
1140
1141 }
1142
1143 static const struct rpc_call_ops nfsd4_cb_ops = {
1144         .rpc_call_prepare = nfsd4_cb_prepare,
1145         .rpc_call_done = nfsd4_cb_done,
1146         .rpc_release = nfsd4_cb_release,
1147 };
1148
1149 int nfsd4_create_callback_queue(void)
1150 {
1151         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1152         if (!callback_wq)
1153                 return -ENOMEM;
1154         return 0;
1155 }
1156
1157 void nfsd4_destroy_callback_queue(void)
1158 {
1159         destroy_workqueue(callback_wq);
1160 }
1161
1162 /* must be called under the state lock */
1163 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1164 {
1165         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1166         /*
1167          * Note this won't actually result in a null callback;
1168          * instead, nfsd4_run_cb_null() will detect the killed
1169          * client, destroy the rpc client, and stop:
1170          */
1171         nfsd4_run_cb(&clp->cl_cb_null);
1172         flush_workqueue(callback_wq);
1173 }
1174
1175 /* requires cl_lock: */
1176 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1177 {
1178         struct nfsd4_session *s;
1179         struct nfsd4_conn *c;
1180
1181         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1182                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1183                         if (c->cn_flags & NFS4_CDFC4_BACK)
1184                                 return c;
1185                 }
1186         }
1187         return NULL;
1188 }
1189
1190 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1191 {
1192         struct nfs4_cb_conn conn;
1193         struct nfs4_client *clp = cb->cb_clp;
1194         struct nfsd4_session *ses = NULL;
1195         struct nfsd4_conn *c;
1196         int err;
1197
1198         /*
1199          * This is either an update, or the client dying; in either case,
1200          * kill the old client:
1201          */
1202         if (clp->cl_cb_client) {
1203                 rpc_shutdown_client(clp->cl_cb_client);
1204                 clp->cl_cb_client = NULL;
1205                 put_cred(clp->cl_cb_cred);
1206                 clp->cl_cb_cred = NULL;
1207         }
1208         if (clp->cl_cb_conn.cb_xprt) {
1209                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1210                 clp->cl_cb_conn.cb_xprt = NULL;
1211         }
1212         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1213                 return;
1214         spin_lock(&clp->cl_lock);
1215         /*
1216          * Only serialized callback code is allowed to clear these
1217          * flags; main nfsd code can only set them:
1218          */
1219         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1220         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1221         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1222         c = __nfsd4_find_backchannel(clp);
1223         if (c) {
1224                 svc_xprt_get(c->cn_xprt);
1225                 conn.cb_xprt = c->cn_xprt;
1226                 ses = c->cn_session;
1227         }
1228         spin_unlock(&clp->cl_lock);
1229
1230         err = setup_callback_client(clp, &conn, ses);
1231         if (err) {
1232                 nfsd4_mark_cb_down(clp, err);
1233                 return;
1234         }
1235 }
1236
1237 static void
1238 nfsd4_run_cb_work(struct work_struct *work)
1239 {
1240         struct nfsd4_callback *cb =
1241                 container_of(work, struct nfsd4_callback, cb_work);
1242         struct nfs4_client *clp = cb->cb_clp;
1243         struct rpc_clnt *clnt;
1244
1245         if (cb->cb_need_restart) {
1246                 cb->cb_need_restart = false;
1247         } else {
1248                 if (cb->cb_ops && cb->cb_ops->prepare)
1249                         cb->cb_ops->prepare(cb);
1250         }
1251
1252         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1253                 nfsd4_process_cb_update(cb);
1254
1255         clnt = clp->cl_cb_client;
1256         if (!clnt) {
1257                 /* Callback channel broken, or client killed; give up: */
1258                 if (cb->cb_ops && cb->cb_ops->release)
1259                         cb->cb_ops->release(cb);
1260                 return;
1261         }
1262
1263         /*
1264          * Don't send probe messages for 4.1 or later.
1265          */
1266         if (!cb->cb_ops && clp->cl_minorversion) {
1267                 clp->cl_cb_state = NFSD4_CB_UP;
1268                 return;
1269         }
1270
1271         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1272         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1273                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1274 }
1275
1276 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1277                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1278 {
1279         cb->cb_clp = clp;
1280         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1281         cb->cb_msg.rpc_argp = cb;
1282         cb->cb_msg.rpc_resp = cb;
1283         cb->cb_ops = ops;
1284         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1285         cb->cb_seq_status = 1;
1286         cb->cb_status = 0;
1287         cb->cb_need_restart = false;
1288         cb->cb_holds_slot = false;
1289 }
1290
1291 void nfsd4_run_cb(struct nfsd4_callback *cb)
1292 {
1293         queue_work(callback_wq, &cb->cb_work);
1294 }