fs/nfsd/nfs4callback.c

   1 /*
   2  *  Copyright (c) 2001 The Regents of the University of Michigan.
   3  *  All rights reserved.
   4  *
   5  *  Kendrick Smith <[email protected]>
   6  *  Andy Adamson <[email protected]>
   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/svc_xprt.h>
  36 #include <linux/slab.h>
  37 #include "nfsd.h"
  38 #include "state.h"
  39
  40 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  41
  42 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  43
  44 #define NFSPROC4_CB_NULL 0
  45 #define NFSPROC4_CB_COMPOUND 1
  46
  47 /* Index of predefined Linux callback client operations */
  48
  49 enum {
  50         NFSPROC4_CLNT_CB_NULL = 0,
  51         NFSPROC4_CLNT_CB_RECALL,
  52         NFSPROC4_CLNT_CB_SEQUENCE,
  53 };
  54
  55 #define NFS4_MAXTAGLEN          20
  56
  57 #define NFS4_enc_cb_null_sz             0
  58 #define NFS4_dec_cb_null_sz             0
  59 #define cb_compound_enc_hdr_sz          4
  60 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
  61 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
  62 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
  63                                         1 /* no referring calls list yet */)
  64 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
  65
  66 #define op_enc_sz                       1
  67 #define op_dec_sz                       2
  68 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
  69 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
  70 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
  71                                         cb_sequence_enc_sz +            \
  72                                         1 + enc_stateid_sz +            \
  73                                         enc_nfs4_fh_sz)
  74
  75 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
  76                                         cb_sequence_dec_sz +            \
  77                                         op_dec_sz)
  78
  79 struct nfs4_cb_compound_hdr {
  80         /* args */
  81         u32             ident;  /* minorversion 0 only */
  82         u32             nops;
  83         __be32          *nops_p;
  84         u32             minorversion;
  85         /* res */
  86         int             status;
  87 };
  88
  89 /*
  90  * Handle decode buffer overflows out-of-line.
  91  */
  92 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  93 {
  94         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  95                 "Remaining buffer length is %tu words.\n",
  96                 func, xdr->end - xdr->p);
  97 }
  98
  99 static __be32 *xdr_encode_empty_array(__be32 *p)
 100 {
 101         *p++ = xdr_zero;
 102         return p;
 103 }
 104
 105 /*
 106  * Encode/decode NFSv4 CB basic data types
 107  *
 108  * Basic NFSv4 callback data types are defined in section 15 of RFC
 109  * 3530: "Network File System (NFS) version 4 Protocol" and section
 110  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
 111  * 1 Protocol"
 112  */
 113
 114 /*
 115  *      nfs_cb_opnum4
 116  *
 117  *      enum nfs_cb_opnum4 {
 118  *              OP_CB_GETATTR           = 3,
 119  *                ...
 120  *      };
 121  */
 122 enum nfs_cb_opnum4 {
 123         OP_CB_GETATTR                   = 3,
 124         OP_CB_RECALL                    = 4,
 125         OP_CB_LAYOUTRECALL              = 5,
 126         OP_CB_NOTIFY                    = 6,
 127         OP_CB_PUSH_DELEG                = 7,
 128         OP_CB_RECALL_ANY                = 8,
 129         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 130         OP_CB_RECALL_SLOT               = 10,
 131         OP_CB_SEQUENCE                  = 11,
 132         OP_CB_WANTS_CANCELLED           = 12,
 133         OP_CB_NOTIFY_LOCK               = 13,
 134         OP_CB_NOTIFY_DEVICEID           = 14,
 135         OP_CB_ILLEGAL                   = 10044
 136 };
 137
 138 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 139 {
 140         __be32 *p;
 141
 142         p = xdr_reserve_space(xdr, 4);
 143         *p = cpu_to_be32(op);
 144 }
 145
 146 /*
 147  * nfs_fh4
 148  *
 149  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 150  */
 151 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 152 {
 153         u32 length = fh->fh_size;
 154         __be32 *p;
 155
 156         BUG_ON(length > NFS4_FHSIZE);
 157         p = xdr_reserve_space(xdr, 4 + length);
 158         xdr_encode_opaque(p, &fh->fh_base, length);
 159 }
 160
 161 /*
 162  * stateid4
 163  *
 164  *      struct stateid4 {
 165  *              uint32_t        seqid;
 166  *              opaque          other[12];
 167  *      };
 168  */
 169 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 170 {
 171         __be32 *p;
 172
 173         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 174         *p++ = cpu_to_be32(sid->si_generation);
 175         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 176 }
 177
 178 /*
 179  * sessionid4
 180  *
 181  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 182  */
 183 static void encode_sessionid4(struct xdr_stream *xdr,
 184                               const struct nfsd4_session *session)
 185 {
 186         __be32 *p;
 187
 188         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 189         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 190                                         NFS4_MAX_SESSIONID_LEN);
 191 }
 192
 193 /*
 194  * nfsstat4
 195  */
 196 static const struct {
 197         int stat;
 198         int errno;
 199 } nfs_cb_errtbl[] = {
 200         { NFS4_OK,              0               },
 201         { NFS4ERR_PERM,         -EPERM          },
 202         { NFS4ERR_NOENT,        -ENOENT         },
 203         { NFS4ERR_IO,           -EIO            },
 204         { NFS4ERR_NXIO,         -ENXIO          },
 205         { NFS4ERR_ACCESS,       -EACCES         },
 206         { NFS4ERR_EXIST,        -EEXIST         },
 207         { NFS4ERR_XDEV,         -EXDEV          },
 208         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 209         { NFS4ERR_ISDIR,        -EISDIR         },
 210         { NFS4ERR_INVAL,        -EINVAL         },
 211         { NFS4ERR_FBIG,         -EFBIG          },
 212         { NFS4ERR_NOSPC,        -ENOSPC         },
 213         { NFS4ERR_ROFS,         -EROFS          },
 214         { NFS4ERR_MLINK,        -EMLINK         },
 215         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 216         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 217         { NFS4ERR_DQUOT,        -EDQUOT         },
 218         { NFS4ERR_STALE,        -ESTALE         },
 219         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 220         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 221         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 222         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 223         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 224         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 225         { NFS4ERR_LOCKED,       -EAGAIN         },
 226         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 227         { NFS4ERR_SYMLINK,      -ELOOP          },
 228         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 229         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 230         { -1,                   -EIO            }
 231 };
 232
 233 /*
 234  * If we cannot translate the error, the recovery routines should
 235  * handle it.
 236  *
 237  * Note: remaining NFSv4 error codes have values > 10000, so should
 238  * not conflict with native Linux error codes.
 239  */
 240 static int nfs_cb_stat_to_errno(int status)
 241 {
 242         int i;
 243
 244         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 245                 if (nfs_cb_errtbl[i].stat == status)
 246                         return nfs_cb_errtbl[i].errno;
 247         }
 248
 249         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 250         return -status;
 251 }
 252
 253 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
 254                                enum nfsstat4 *status)
 255 {
 256         __be32 *p;
 257         u32 op;
 258
 259         p = xdr_inline_decode(xdr, 4 + 4);
 260         if (unlikely(p == NULL))
 261                 goto out_overflow;
 262         op = be32_to_cpup(p++);
 263         if (unlikely(op != expected))
 264                 goto out_unexpected;
 265         *status = be32_to_cpup(p);
 266         return 0;
 267 out_overflow:
 268         print_overflow_msg(__func__, xdr);
 269         return -EIO;
 270 out_unexpected:
 271         dprintk("NFSD: Callback server returned operation %d but "
 272                 "we issued a request for %d\n", op, expected);
 273         return -EIO;
 274 }
 275
 276 /*
 277  * CB_COMPOUND4args
 278  *
 279  *      struct CB_COMPOUND4args {
 280  *              utf8str_cs      tag;
 281  *              uint32_t        minorversion;
 282  *              uint32_t        callback_ident;
 283  *              nfs_cb_argop4   argarray<>;
 284  *      };
 285 */
 286 static void encode_cb_compound4args(struct xdr_stream *xdr,
 287                                     struct nfs4_cb_compound_hdr *hdr)
 288 {
 289         __be32 * p;
 290
 291         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 292         p = xdr_encode_empty_array(p);          /* empty tag */
 293         *p++ = cpu_to_be32(hdr->minorversion);
 294         *p++ = cpu_to_be32(hdr->ident);
 295
 296         hdr->nops_p = p;
 297         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 298 }
 299
 300 /*
 301  * Update argarray element count
 302  */
 303 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 304 {
 305         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 306         *hdr->nops_p = cpu_to_be32(hdr->nops);
 307 }
 308
 309 /*
 310  * CB_COMPOUND4res
 311  *
 312  *      struct CB_COMPOUND4res {
 313  *              nfsstat4        status;
 314  *              utf8str_cs      tag;
 315  *              nfs_cb_resop4   resarray<>;
 316  *      };
 317  */
 318 static int decode_cb_compound4res(struct xdr_stream *xdr,
 319                                   struct nfs4_cb_compound_hdr *hdr)
 320 {
 321         u32 length;
 322         __be32 *p;
 323
 324         p = xdr_inline_decode(xdr, 4 + 4);
 325         if (unlikely(p == NULL))
 326                 goto out_overflow;
 327         hdr->status = be32_to_cpup(p++);
 328         /* Ignore the tag */
 329         length = be32_to_cpup(p++);
 330         p = xdr_inline_decode(xdr, length + 4);
 331         if (unlikely(p == NULL))
 332                 goto out_overflow;
 333         hdr->nops = be32_to_cpup(p);
 334         return 0;
 335 out_overflow:
 336         print_overflow_msg(__func__, xdr);
 337         return -EIO;
 338 }
 339
 340 /*
 341  * CB_RECALL4args
 342  *
 343  *      struct CB_RECALL4args {
 344  *              stateid4        stateid;
 345  *              bool            truncate;
 346  *              nfs_fh4         fh;
 347  *      };
 348  */
 349 static void encode_cb_recall4args(struct xdr_stream *xdr,
 350                                   const struct nfs4_delegation *dp,
 351                                   struct nfs4_cb_compound_hdr *hdr)
 352 {
 353         __be32 *p;
 354
 355         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 356         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 357
 358         p = xdr_reserve_space(xdr, 4);
 359         *p++ = xdr_zero;                        /* truncate */
 360
 361         encode_nfs_fh4(xdr, &dp->dl_fh);
 362
 363         hdr->nops++;
 364 }
 365
 366 /*
 367  * CB_SEQUENCE4args
 368  *
 369  *      struct CB_SEQUENCE4args {
 370  *              sessionid4              csa_sessionid;
 371  *              sequenceid4             csa_sequenceid;
 372  *              slotid4                 csa_slotid;
 373  *              slotid4                 csa_highest_slotid;
 374  *              bool                    csa_cachethis;
 375  *              referring_call_list4    csa_referring_call_lists<>;
 376  *      };
 377  */
 378 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 379                                     const struct nfsd4_callback *cb,
 380                                     struct nfs4_cb_compound_hdr *hdr)
 381 {
 382         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 383         __be32 *p;
 384
 385         if (hdr->minorversion == 0)
 386                 return;
 387
 388         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 389         encode_sessionid4(xdr, session);
 390
 391         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 392         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 393         *p++ = xdr_zero;                        /* csa_slotid */
 394         *p++ = xdr_zero;                        /* csa_highest_slotid */
 395         *p++ = xdr_zero;                        /* csa_cachethis */
 396         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 397
 398         hdr->nops++;
 399 }
 400
 401 /*
 402  * CB_SEQUENCE4resok
 403  *
 404  *      struct CB_SEQUENCE4resok {
 405  *              sessionid4      csr_sessionid;
 406  *              sequenceid4     csr_sequenceid;
 407  *              slotid4         csr_slotid;
 408  *              slotid4         csr_highest_slotid;
 409  *              slotid4         csr_target_highest_slotid;
 410  *      };
 411  *
 412  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 413  *      case NFS4_OK:
 414  *              CB_SEQUENCE4resok       csr_resok4;
 415  *      default:
 416  *              void;
 417  *      };
 418  *
 419  * Our current back channel implmentation supports a single backchannel
 420  * with a single slot.
 421  */
 422 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 423                                     struct nfsd4_callback *cb)
 424 {
 425         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 426         struct nfs4_sessionid id;
 427         int status;
 428         __be32 *p;
 429         u32 dummy;
 430
 431         status = -ESERVERFAULT;
 432
 433         /*
 434          * If the server returns different values for sessionID, slotID or
 435          * sequence number, the server is looney tunes.
 436          */
 437         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 438         if (unlikely(p == NULL))
 439                 goto out_overflow;
 440         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 441         if (memcmp(id.data, session->se_sessionid.data,
 442                                         NFS4_MAX_SESSIONID_LEN) != 0) {
 443                 dprintk("NFS: %s Invalid session id\n", __func__);
 444                 goto out;
 445         }
 446         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 447
 448         dummy = be32_to_cpup(p++);
 449         if (dummy != session->se_cb_seq_nr) {
 450                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 451                 goto out;
 452         }
 453
 454         dummy = be32_to_cpup(p++);
 455         if (dummy != 0) {
 456                 dprintk("NFS: %s Invalid slotid\n", __func__);
 457                 goto out;
 458         }
 459
 460         /*
 461          * FIXME: process highest slotid and target highest slotid
 462          */
 463         status = 0;
 464 out:
 465         if (status)
 466                 nfsd4_mark_cb_fault(cb->cb_clp, status);
 467         return status;
 468 out_overflow:
 469         print_overflow_msg(__func__, xdr);
 470         return -EIO;
 471 }
 472
 473 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 474                                   struct nfsd4_callback *cb)
 475 {
 476         enum nfsstat4 nfserr;
 477         int status;
 478
 479         if (cb->cb_minorversion == 0)
 480                 return 0;
 481
 482         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
 483         if (unlikely(status))
 484                 goto out;
 485         if (unlikely(nfserr != NFS4_OK))
 486                 goto out_default;
 487         status = decode_cb_sequence4resok(xdr, cb);
 488 out:
 489         return status;
 490 out_default:
 491         return nfs_cb_stat_to_errno(nfserr);
 492 }
 493
 494 /*
 495  * NFSv4.0 and NFSv4.1 XDR encode functions
 496  *
 497  * NFSv4.0 callback argument types are defined in section 15 of RFC
 498  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 499  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 500  * Protocol".
 501  */
 502
 503 /*
 504  * NB: Without this zero space reservation, callbacks over krb5p fail
 505  */
 506 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 507                                  void *__unused)
 508 {
 509         xdr_reserve_space(xdr, 0);
 510 }
 511
 512 /*
 513  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 514  */
 515 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 516                                    const struct nfsd4_callback *cb)
 517 {
 518         const struct nfs4_delegation *args = cb->cb_op;
 519         struct nfs4_cb_compound_hdr hdr = {
 520                 .ident = cb->cb_clp->cl_cb_ident,
 521                 .minorversion = cb->cb_minorversion,
 522         };
 523
 524         encode_cb_compound4args(xdr, &hdr);
 525         encode_cb_sequence4args(xdr, cb, &hdr);
 526         encode_cb_recall4args(xdr, args, &hdr);
 527         encode_cb_nops(&hdr);
 528 }
 529
 530
 531 /*
 532  * NFSv4.0 and NFSv4.1 XDR decode functions
 533  *
 534  * NFSv4.0 callback result types are defined in section 15 of RFC
 535  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 536  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 537  * Protocol".
 538  */
 539
 540 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 541                                 void *__unused)
 542 {
 543         return 0;
 544 }
 545
 546 /*
 547  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 548  */
 549 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 550                                   struct xdr_stream *xdr,
 551                                   struct nfsd4_callback *cb)
 552 {
 553         struct nfs4_cb_compound_hdr hdr;
 554         enum nfsstat4 nfserr;
 555         int status;
 556
 557         status = decode_cb_compound4res(xdr, &hdr);
 558         if (unlikely(status))
 559                 goto out;
 560
 561         if (cb != NULL) {
 562                 status = decode_cb_sequence4res(xdr, cb);
 563                 if (unlikely(status))
 564                         goto out;
 565         }
 566
 567         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
 568         if (unlikely(status))
 569                 goto out;
 570         if (unlikely(nfserr != NFS4_OK))
 571                 status = nfs_cb_stat_to_errno(nfserr);
 572 out:
 573         return status;
 574 }
 575
 576 /*
 577  * RPC procedure tables
 578  */
 579 #define PROC(proc, call, argtype, restype)                              \
 580 [NFSPROC4_CLNT_##proc] = {                                              \
 581         .p_proc    = NFSPROC4_CB_##call,                                \
 582         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 583         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 584         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 585         .p_replen  = NFS4_dec_##restype##_sz,                           \
 586         .p_statidx = NFSPROC4_CB_##call,                                \
 587         .p_name    = #proc,                                             \
 588 }
 589
 590 static struct rpc_procinfo nfs4_cb_procedures[] = {
 591         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 592         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 593 };
 594
 595 static struct rpc_version nfs_cb_version4 = {
 596 /*
 597  * Note on the callback rpc program version number: despite language in rfc
 598  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 599  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 600  * in practice that appears to be what implementations use.  The section
 601  * 18.36.3 language is expected to be fixed in an erratum.
 602  */
 603         .number                 = 1,
 604         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 605         .procs                  = nfs4_cb_procedures
 606 };
 607
 608 static const struct rpc_version *nfs_cb_version[] = {
 609         &nfs_cb_version4,
 610 };
 611
 612 static const struct rpc_program cb_program;
 613
 614 static struct rpc_stat cb_stats = {
 615         .program                = &cb_program
 616 };
 617
 618 #define NFS4_CALLBACK 0x40000000
 619 static const struct rpc_program cb_program = {
 620         .name                   = "nfs4_cb",
 621         .number                 = NFS4_CALLBACK,
 622         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 623         .version                = nfs_cb_version,
 624         .stats                  = &cb_stats,
 625         .pipe_dir_name          = "nfsd4_cb",
 626 };
 627
 628 static int max_cb_time(void)
 629 {
 630         return max(nfsd4_lease/10, (time_t)1) * HZ;
 631 }
 632
 633
 634 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 635 {
 636         struct rpc_timeout      timeparms = {
 637                 .to_initval     = max_cb_time(),
 638                 .to_retries     = 0,
 639         };
 640         struct rpc_create_args args = {
 641                 .net            = &init_net,
 642                 .address        = (struct sockaddr *) &conn->cb_addr,
 643                 .addrsize       = conn->cb_addrlen,
 644                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 645                 .timeout        = &timeparms,
 646                 .program        = &cb_program,
 647                 .version        = 0,
 648                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 649         };
 650         struct rpc_clnt *client;
 651
 652         if (clp->cl_minorversion == 0) {
 653                 if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 654                         return -EINVAL;
 655                 args.client_name = clp->cl_principal;
 656                 args.prognumber = conn->cb_prog,
 657                 args.protocol = XPRT_TRANSPORT_TCP;
 658                 args.authflavor = clp->cl_flavor;
 659                 clp->cl_cb_ident = conn->cb_ident;
 660         } else {
 661                 if (!conn->cb_xprt)
 662                         return -EINVAL;
 663                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 664                 clp->cl_cb_session = ses;
 665                 args.bc_xprt = conn->cb_xprt;
 666                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 667                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 668                 args.authflavor = RPC_AUTH_UNIX;
 669         }
 670         /* Create RPC client */
 671         client = rpc_create(&args);
 672         if (IS_ERR(client)) {
 673                 dprintk("NFSD: couldn't create callback client: %ld\n",
 674                         PTR_ERR(client));
 675                 return PTR_ERR(client);
 676         }
 677         clp->cl_cb_client = client;
 678         return 0;
 679
 680 }
 681
 682 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 683 {
 684         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 685                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 686 }
 687
 688 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 689 {
 690         clp->cl_cb_state = NFSD4_CB_DOWN;
 691         warn_no_callback_path(clp, reason);
 692 }
 693
 694 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 695 {
 696         clp->cl_cb_state = NFSD4_CB_FAULT;
 697         warn_no_callback_path(clp, reason);
 698 }
 699
 700 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 701 {
 702         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 703
 704         if (task->tk_status)
 705                 nfsd4_mark_cb_down(clp, task->tk_status);
 706         else
 707                 clp->cl_cb_state = NFSD4_CB_UP;
 708 }
 709
 710 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 711         /* XXX: release method to ensure we set the cb channel down if
 712          * necessary on early failure? */
 713         .rpc_call_done = nfsd4_cb_probe_done,
 714 };
 715
 716 static struct rpc_cred *callback_cred;
 717
 718 int set_callback_cred(void)
 719 {
 720         if (callback_cred)
 721                 return 0;
 722         callback_cred = rpc_lookup_machine_cred("nfs");
 723         if (!callback_cred)
 724                 return -ENOMEM;
 725         return 0;
 726 }
 727
 728 static struct workqueue_struct *callback_wq;
 729
 730 static void run_nfsd4_cb(struct nfsd4_callback *cb)
 731 {
 732         queue_work(callback_wq, &cb->cb_work);
 733 }
 734
 735 static void do_probe_callback(struct nfs4_client *clp)
 736 {
 737         struct nfsd4_callback *cb = &clp->cl_cb_null;
 738
 739         cb->cb_op = NULL;
 740         cb->cb_clp = clp;
 741
 742         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
 743         cb->cb_msg.rpc_argp = NULL;
 744         cb->cb_msg.rpc_resp = NULL;
 745         cb->cb_msg.rpc_cred = callback_cred;
 746
 747         cb->cb_ops = &nfsd4_cb_probe_ops;
 748
 749         run_nfsd4_cb(cb);
 750 }
 751
 752 /*
 753  * Poke the callback thread to process any updates to the callback
 754  * parameters, and send a null probe.
 755  */
 756 void nfsd4_probe_callback(struct nfs4_client *clp)
 757 {
 758         /* XXX: atomicity?  Also, should we be using cl_flags? */
 759         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 760         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 761         do_probe_callback(clp);
 762 }
 763
 764 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 765 {
 766         nfsd4_probe_callback(clp);
 767         flush_workqueue(callback_wq);
 768 }
 769
 770 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 771 {
 772         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 773         spin_lock(&clp->cl_lock);
 774         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 775         spin_unlock(&clp->cl_lock);
 776 }
 777
 778 /*
 779  * There's currently a single callback channel slot.
 780  * If the slot is available, then mark it busy.  Otherwise, set the
 781  * thread for sleeping on the callback RPC wait queue.
 782  */
 783 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 784 {
 785         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 786                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 787                 dprintk("%s slot is busy\n", __func__);
 788                 return false;
 789         }
 790         return true;
 791 }
 792
 793 /*
 794  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 795  * slots, and mark callback channel down on communication errors.
 796  */
 797 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 798 {
 799         struct nfsd4_callback *cb = calldata;
 800         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 801         struct nfs4_client *clp = dp->dl_stid.sc_client;
 802         u32 minorversion = clp->cl_minorversion;
 803
 804         cb->cb_minorversion = minorversion;
 805         if (minorversion) {
 806                 if (!nfsd41_cb_get_slot(clp, task))
 807                         return;
 808         }
 809         spin_lock(&clp->cl_lock);
 810         if (list_empty(&cb->cb_per_client)) {
 811                 /* This is the first call, not a restart */
 812                 cb->cb_done = false;
 813                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
 814         }
 815         spin_unlock(&clp->cl_lock);
 816         rpc_call_start(task);
 817 }
 818
 819 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 820 {
 821         struct nfsd4_callback *cb = calldata;
 822         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 823         struct nfs4_client *clp = dp->dl_stid.sc_client;
 824
 825         dprintk("%s: minorversion=%d\n", __func__,
 826                 clp->cl_minorversion);
 827
 828         if (clp->cl_minorversion) {
 829                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 830                 ++clp->cl_cb_session->se_cb_seq_nr;
 831                 clear_bit(0, &clp->cl_cb_slot_busy);
 832                 rpc_wake_up_next(&clp->cl_cb_waitq);
 833                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 834                         clp->cl_cb_session->se_cb_seq_nr);
 835
 836                 /* We're done looking into the sequence information */
 837                 task->tk_msg.rpc_resp = NULL;
 838         }
 839 }
 840
 841
 842 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 843 {
 844         struct nfsd4_callback *cb = calldata;
 845         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 846         struct nfs4_client *clp = dp->dl_stid.sc_client;
 847         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 848
 849         nfsd4_cb_done(task, calldata);
 850
 851         if (current_rpc_client != task->tk_client) {
 852                 /* We're shutting down or changing cl_cb_client; leave
 853                  * it to nfsd4_process_cb_update to restart the call if
 854                  * necessary. */
 855                 return;
 856         }
 857
 858         if (cb->cb_done)
 859                 return;
 860         switch (task->tk_status) {
 861         case 0:
 862                 cb->cb_done = true;
 863                 return;
 864         case -EBADHANDLE:
 865         case -NFS4ERR_BAD_STATEID:
 866                 /* Race: client probably got cb_recall
 867                  * before open reply granting delegation */
 868                 break;
 869         default:
 870                 /* Network partition? */
 871                 nfsd4_mark_cb_down(clp, task->tk_status);
 872         }
 873         if (dp->dl_retries--) {
 874                 rpc_delay(task, 2*HZ);
 875                 task->tk_status = 0;
 876                 rpc_restart_call_prepare(task);
 877                 return;
 878         }
 879         nfsd4_mark_cb_down(clp, task->tk_status);
 880         cb->cb_done = true;
 881 }
 882
 883 static void nfsd4_cb_recall_release(void *calldata)
 884 {
 885         struct nfsd4_callback *cb = calldata;
 886         struct nfs4_client *clp = cb->cb_clp;
 887         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 888
 889         if (cb->cb_done) {
 890                 spin_lock(&clp->cl_lock);
 891                 list_del(&cb->cb_per_client);
 892                 spin_unlock(&clp->cl_lock);
 893                 nfs4_put_delegation(dp);
 894         }
 895 }
 896
 897 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 898         .rpc_call_prepare = nfsd4_cb_prepare,
 899         .rpc_call_done = nfsd4_cb_recall_done,
 900         .rpc_release = nfsd4_cb_recall_release,
 901 };
 902
 903 int nfsd4_create_callback_queue(void)
 904 {
 905         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 906         if (!callback_wq)
 907                 return -ENOMEM;
 908         return 0;
 909 }
 910
 911 void nfsd4_destroy_callback_queue(void)
 912 {
 913         destroy_workqueue(callback_wq);
 914 }
 915
 916 /* must be called under the state lock */
 917 void nfsd4_shutdown_callback(struct nfs4_client *clp)
 918 {
 919         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
 920         /*
 921          * Note this won't actually result in a null callback;
 922          * instead, nfsd4_do_callback_rpc() will detect the killed
 923          * client, destroy the rpc client, and stop:
 924          */
 925         do_probe_callback(clp);
 926         flush_workqueue(callback_wq);
 927 }
 928
 929 static void nfsd4_release_cb(struct nfsd4_callback *cb)
 930 {
 931         if (cb->cb_ops->rpc_release)
 932                 cb->cb_ops->rpc_release(cb);
 933 }
 934
 935 /* requires cl_lock: */
 936 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 937 {
 938         struct nfsd4_session *s;
 939         struct nfsd4_conn *c;
 940
 941         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 942                 list_for_each_entry(c, &s->se_conns, cn_persession) {
 943                         if (c->cn_flags & NFS4_CDFC4_BACK)
 944                                 return c;
 945                 }
 946         }
 947         return NULL;
 948 }
 949
 950 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 951 {
 952         struct nfs4_cb_conn conn;
 953         struct nfs4_client *clp = cb->cb_clp;
 954         struct nfsd4_session *ses = NULL;
 955         struct nfsd4_conn *c;
 956         int err;
 957
 958         /*
 959          * This is either an update, or the client dying; in either case,
 960          * kill the old client:
 961          */
 962         if (clp->cl_cb_client) {
 963                 rpc_shutdown_client(clp->cl_cb_client);
 964                 clp->cl_cb_client = NULL;
 965         }
 966         if (clp->cl_cb_conn.cb_xprt) {
 967                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 968                 clp->cl_cb_conn.cb_xprt = NULL;
 969         }
 970         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
 971                 return;
 972         spin_lock(&clp->cl_lock);
 973         /*
 974          * Only serialized callback code is allowed to clear these
 975          * flags; main nfsd code can only set them:
 976          */
 977         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
 978         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 979         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
 980         c = __nfsd4_find_backchannel(clp);
 981         if (c) {
 982                 svc_xprt_get(c->cn_xprt);
 983                 conn.cb_xprt = c->cn_xprt;
 984                 ses = c->cn_session;
 985         }
 986         spin_unlock(&clp->cl_lock);
 987
 988         err = setup_callback_client(clp, &conn, ses);
 989         if (err) {
 990                 nfsd4_mark_cb_down(clp, err);
 991                 return;
 992         }
 993         /* Yay, the callback channel's back! Restart any callbacks: */
 994         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
 995                 run_nfsd4_cb(cb);
 996 }
 997
 998 void nfsd4_do_callback_rpc(struct work_struct *w)
 999 {
1000         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
1001         struct nfs4_client *clp = cb->cb_clp;
1002         struct rpc_clnt *clnt;
1003
1004         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1005                 nfsd4_process_cb_update(cb);
1006
1007         clnt = clp->cl_cb_client;
1008         if (!clnt) {
1009                 /* Callback channel broken, or client killed; give up: */
1010                 nfsd4_release_cb(cb);
1011                 return;
1012         }
1013         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1014                         cb->cb_ops, cb);
1015 }
1016
1017 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1018 {
1019         struct nfsd4_callback *cb = &dp->dl_recall;
1020         struct nfs4_client *clp = dp->dl_stid.sc_client;
1021
1022         dp->dl_retries = 1;
1023         cb->cb_op = dp;
1024         cb->cb_clp = clp;
1025         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1026         cb->cb_msg.rpc_argp = cb;
1027         cb->cb_msg.rpc_resp = cb;
1028         cb->cb_msg.rpc_cred = callback_cred;
1029
1030         cb->cb_ops = &nfsd4_cb_recall_ops;
1031         dp->dl_retries = 1;
1032
1033         INIT_LIST_HEAD(&cb->cb_per_client);
1034         cb->cb_done = true;
1035
1036         run_nfsd4_cb(&dp->dl_recall);
1037 }