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, enum nfs_opnum4 expected,
 227                                enum nfsstat4 *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 = 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         hdr->nops = be32_to_cpup(p);
 307         return 0;
 308 out_overflow:
 309         print_overflow_msg(__func__, xdr);
 310         return -EIO;
 311 }
 312
 313 /*
 314  * CB_RECALL4args
 315  *
 316  *      struct CB_RECALL4args {
 317  *              stateid4        stateid;
 318  *              bool            truncate;
 319  *              nfs_fh4         fh;
 320  *      };
 321  */
 322 static void encode_cb_recall4args(struct xdr_stream *xdr,
 323                                   const struct nfs4_delegation *dp,
 324                                   struct nfs4_cb_compound_hdr *hdr)
 325 {
 326         __be32 *p;
 327
 328         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 329         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 330
 331         p = xdr_reserve_space(xdr, 4);
 332         *p++ = xdr_zero;                        /* truncate */
 333
 334         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 335
 336         hdr->nops++;
 337 }
 338
 339 /*
 340  * CB_SEQUENCE4args
 341  *
 342  *      struct CB_SEQUENCE4args {
 343  *              sessionid4              csa_sessionid;
 344  *              sequenceid4             csa_sequenceid;
 345  *              slotid4                 csa_slotid;
 346  *              slotid4                 csa_highest_slotid;
 347  *              bool                    csa_cachethis;
 348  *              referring_call_list4    csa_referring_call_lists<>;
 349  *      };
 350  */
 351 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 352                                     const struct nfsd4_callback *cb,
 353                                     struct nfs4_cb_compound_hdr *hdr)
 354 {
 355         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 356         __be32 *p;
 357
 358         if (hdr->minorversion == 0)
 359                 return;
 360
 361         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 362         encode_sessionid4(xdr, session);
 363
 364         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 365         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 366         *p++ = xdr_zero;                        /* csa_slotid */
 367         *p++ = xdr_zero;                        /* csa_highest_slotid */
 368         *p++ = xdr_zero;                        /* csa_cachethis */
 369         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 370
 371         hdr->nops++;
 372 }
 373
 374 /*
 375  * CB_SEQUENCE4resok
 376  *
 377  *      struct CB_SEQUENCE4resok {
 378  *              sessionid4      csr_sessionid;
 379  *              sequenceid4     csr_sequenceid;
 380  *              slotid4         csr_slotid;
 381  *              slotid4         csr_highest_slotid;
 382  *              slotid4         csr_target_highest_slotid;
 383  *      };
 384  *
 385  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 386  *      case NFS4_OK:
 387  *              CB_SEQUENCE4resok       csr_resok4;
 388  *      default:
 389  *              void;
 390  *      };
 391  *
 392  * Our current back channel implmentation supports a single backchannel
 393  * with a single slot.
 394  */
 395 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 396                                     struct nfsd4_callback *cb)
 397 {
 398         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 399         struct nfs4_sessionid id;
 400         int status;
 401         __be32 *p;
 402         u32 dummy;
 403
 404         status = -ESERVERFAULT;
 405
 406         /*
 407          * If the server returns different values for sessionID, slotID or
 408          * sequence number, the server is looney tunes.
 409          */
 410         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 411         if (unlikely(p == NULL))
 412                 goto out_overflow;
 413         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 414         if (memcmp(id.data, session->se_sessionid.data,
 415                                         NFS4_MAX_SESSIONID_LEN) != 0) {
 416                 dprintk("NFS: %s Invalid session id\n", __func__);
 417                 goto out;
 418         }
 419         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 420
 421         dummy = be32_to_cpup(p++);
 422         if (dummy != session->se_cb_seq_nr) {
 423                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 424                 goto out;
 425         }
 426
 427         dummy = be32_to_cpup(p++);
 428         if (dummy != 0) {
 429                 dprintk("NFS: %s Invalid slotid\n", __func__);
 430                 goto out;
 431         }
 432
 433         /*
 434          * FIXME: process highest slotid and target highest slotid
 435          */
 436         status = 0;
 437 out:
 438         if (status)
 439                 nfsd4_mark_cb_fault(cb->cb_clp, status);
 440         return status;
 441 out_overflow:
 442         print_overflow_msg(__func__, xdr);
 443         return -EIO;
 444 }
 445
 446 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 447                                   struct nfsd4_callback *cb)
 448 {
 449         enum nfsstat4 nfserr;
 450         int status;
 451
 452         if (cb->cb_minorversion == 0)
 453                 return 0;
 454
 455         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
 456         if (unlikely(status))
 457                 goto out;
 458         if (unlikely(nfserr != NFS4_OK))
 459                 goto out_default;
 460         status = decode_cb_sequence4resok(xdr, cb);
 461 out:
 462         return status;
 463 out_default:
 464         return nfs_cb_stat_to_errno(nfserr);
 465 }
 466
 467 /*
 468  * NFSv4.0 and NFSv4.1 XDR encode functions
 469  *
 470  * NFSv4.0 callback argument types are defined in section 15 of RFC
 471  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 472  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 473  * Protocol".
 474  */
 475
 476 /*
 477  * NB: Without this zero space reservation, callbacks over krb5p fail
 478  */
 479 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 480                                  void *__unused)
 481 {
 482         xdr_reserve_space(xdr, 0);
 483 }
 484
 485 /*
 486  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 487  */
 488 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 489                                    const struct nfsd4_callback *cb)
 490 {
 491         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 492         struct nfs4_cb_compound_hdr hdr = {
 493                 .ident = cb->cb_clp->cl_cb_ident,
 494                 .minorversion = cb->cb_minorversion,
 495         };
 496
 497         encode_cb_compound4args(xdr, &hdr);
 498         encode_cb_sequence4args(xdr, cb, &hdr);
 499         encode_cb_recall4args(xdr, dp, &hdr);
 500         encode_cb_nops(&hdr);
 501 }
 502
 503
 504 /*
 505  * NFSv4.0 and NFSv4.1 XDR decode functions
 506  *
 507  * NFSv4.0 callback result types are defined in section 15 of RFC
 508  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 509  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 510  * Protocol".
 511  */
 512
 513 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 514                                 void *__unused)
 515 {
 516         return 0;
 517 }
 518
 519 /*
 520  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 521  */
 522 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 523                                   struct xdr_stream *xdr,
 524                                   struct nfsd4_callback *cb)
 525 {
 526         struct nfs4_cb_compound_hdr hdr;
 527         enum nfsstat4 nfserr;
 528         int status;
 529
 530         status = decode_cb_compound4res(xdr, &hdr);
 531         if (unlikely(status))
 532                 goto out;
 533
 534         if (cb != NULL) {
 535                 status = decode_cb_sequence4res(xdr, cb);
 536                 if (unlikely(status))
 537                         goto out;
 538         }
 539
 540         status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
 541         if (unlikely(status))
 542                 goto out;
 543         if (unlikely(nfserr != NFS4_OK))
 544                 status = nfs_cb_stat_to_errno(nfserr);
 545 out:
 546         return status;
 547 }
 548
 549 /*
 550  * RPC procedure tables
 551  */
 552 #define PROC(proc, call, argtype, restype)                              \
 553 [NFSPROC4_CLNT_##proc] = {                                              \
 554         .p_proc    = NFSPROC4_CB_##call,                                \
 555         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 556         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 557         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 558         .p_replen  = NFS4_dec_##restype##_sz,                           \
 559         .p_statidx = NFSPROC4_CB_##call,                                \
 560         .p_name    = #proc,                                             \
 561 }
 562
 563 static struct rpc_procinfo nfs4_cb_procedures[] = {
 564         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 565         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 566 };
 567
 568 static struct rpc_version nfs_cb_version4 = {
 569 /*
 570  * Note on the callback rpc program version number: despite language in rfc
 571  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 572  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 573  * in practice that appears to be what implementations use.  The section
 574  * 18.36.3 language is expected to be fixed in an erratum.
 575  */
 576         .number                 = 1,
 577         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 578         .procs                  = nfs4_cb_procedures
 579 };
 580
 581 static const struct rpc_version *nfs_cb_version[] = {
 582         &nfs_cb_version4,
 583 };
 584
 585 static const struct rpc_program cb_program;
 586
 587 static struct rpc_stat cb_stats = {
 588         .program                = &cb_program
 589 };
 590
 591 #define NFS4_CALLBACK 0x40000000
 592 static const struct rpc_program cb_program = {
 593         .name                   = "nfs4_cb",
 594         .number                 = NFS4_CALLBACK,
 595         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 596         .version                = nfs_cb_version,
 597         .stats                  = &cb_stats,
 598         .pipe_dir_name          = "nfsd4_cb",
 599 };
 600
 601 static int max_cb_time(struct net *net)
 602 {
 603         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 604         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 605 }
 606
 607 static struct rpc_cred *callback_cred;
 608
 609 int set_callback_cred(void)
 610 {
 611         if (callback_cred)
 612                 return 0;
 613         callback_cred = rpc_lookup_machine_cred("nfs");
 614         if (!callback_cred)
 615                 return -ENOMEM;
 616         return 0;
 617 }
 618
 619 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 620 {
 621         if (clp->cl_minorversion == 0) {
 622                 return get_rpccred(callback_cred);
 623         } else {
 624                 struct rpc_auth *auth = client->cl_auth;
 625                 struct auth_cred acred = {};
 626
 627                 acred.uid = ses->se_cb_sec.uid;
 628                 acred.gid = ses->se_cb_sec.gid;
 629                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
 630         }
 631 }
 632
 633 static struct rpc_clnt *create_backchannel_client(struct rpc_create_args *args)
 634 {
 635         struct rpc_xprt *xprt;
 636
 637         if (args->protocol != XPRT_TRANSPORT_BC_TCP)
 638                 return rpc_create(args);
 639
 640         xprt = args->bc_xprt->xpt_bc_xprt;
 641         if (xprt) {
 642                 xprt_get(xprt);
 643                 return rpc_create_xprt(args, xprt);
 644         }
 645
 646         return rpc_create(args);
 647 }
 648
 649 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 650 {
 651         int maxtime = max_cb_time(clp->net);
 652         struct rpc_timeout      timeparms = {
 653                 .to_initval     = maxtime,
 654                 .to_retries     = 0,
 655                 .to_maxval      = maxtime,
 656         };
 657         struct rpc_create_args args = {
 658                 .net            = clp->net,
 659                 .address        = (struct sockaddr *) &conn->cb_addr,
 660                 .addrsize       = conn->cb_addrlen,
 661                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 662                 .timeout        = &timeparms,
 663                 .program        = &cb_program,
 664                 .version        = 0,
 665                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 666         };
 667         struct rpc_clnt *client;
 668         struct rpc_cred *cred;
 669
 670         if (clp->cl_minorversion == 0) {
 671                 if (!clp->cl_cred.cr_principal &&
 672                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 673                         return -EINVAL;
 674                 args.client_name = clp->cl_cred.cr_principal;
 675                 args.prognumber = conn->cb_prog;
 676                 args.protocol = XPRT_TRANSPORT_TCP;
 677                 args.authflavor = clp->cl_cred.cr_flavor;
 678                 clp->cl_cb_ident = conn->cb_ident;
 679         } else {
 680                 if (!conn->cb_xprt)
 681                         return -EINVAL;
 682                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 683                 clp->cl_cb_session = ses;
 684                 args.bc_xprt = conn->cb_xprt;
 685                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 686                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 687                                 XPRT_TRANSPORT_BC;
 688                 args.authflavor = ses->se_cb_sec.flavor;
 689         }
 690         /* Create RPC client */
 691         client = create_backchannel_client(&args);
 692         if (IS_ERR(client)) {
 693                 dprintk("NFSD: couldn't create callback client: %ld\n",
 694                         PTR_ERR(client));
 695                 return PTR_ERR(client);
 696         }
 697         cred = get_backchannel_cred(clp, client, ses);
 698         if (IS_ERR(cred)) {
 699                 rpc_shutdown_client(client);
 700                 return PTR_ERR(cred);
 701         }
 702         clp->cl_cb_client = client;
 703         clp->cl_cb_cred = cred;
 704         return 0;
 705 }
 706
 707 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 708 {
 709         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 710                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 711 }
 712
 713 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 714 {
 715         clp->cl_cb_state = NFSD4_CB_DOWN;
 716         warn_no_callback_path(clp, reason);
 717 }
 718
 719 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 720 {
 721         clp->cl_cb_state = NFSD4_CB_FAULT;
 722         warn_no_callback_path(clp, reason);
 723 }
 724
 725 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 726 {
 727         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 728
 729         if (task->tk_status)
 730                 nfsd4_mark_cb_down(clp, task->tk_status);
 731         else
 732                 clp->cl_cb_state = NFSD4_CB_UP;
 733 }
 734
 735 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 736         /* XXX: release method to ensure we set the cb channel down if
 737          * necessary on early failure? */
 738         .rpc_call_done = nfsd4_cb_probe_done,
 739 };
 740
 741 static struct workqueue_struct *callback_wq;
 742
 743 /*
 744  * Poke the callback thread to process any updates to the callback
 745  * parameters, and send a null probe.
 746  */
 747 void nfsd4_probe_callback(struct nfs4_client *clp)
 748 {
 749         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 750         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 751         nfsd4_run_cb(&clp->cl_cb_null);
 752 }
 753
 754 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 755 {
 756         nfsd4_probe_callback(clp);
 757         flush_workqueue(callback_wq);
 758 }
 759
 760 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 761 {
 762         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 763         spin_lock(&clp->cl_lock);
 764         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 765         spin_unlock(&clp->cl_lock);
 766 }
 767
 768 /*
 769  * There's currently a single callback channel slot.
 770  * If the slot is available, then mark it busy.  Otherwise, set the
 771  * thread for sleeping on the callback RPC wait queue.
 772  */
 773 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 774 {
 775         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 776                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 777                 /* Race breaker */
 778                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 779                         dprintk("%s slot is busy\n", __func__);
 780                         return false;
 781                 }
 782                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
 783         }
 784         return true;
 785 }
 786
 787 /*
 788  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 789  * slots, and mark callback channel down on communication errors.
 790  */
 791 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 792 {
 793         struct nfsd4_callback *cb = calldata;
 794         struct nfs4_client *clp = cb->cb_clp;
 795         u32 minorversion = clp->cl_minorversion;
 796
 797         cb->cb_minorversion = minorversion;
 798         if (minorversion) {
 799                 if (!nfsd41_cb_get_slot(clp, task))
 800                         return;
 801         }
 802         spin_lock(&clp->cl_lock);
 803         if (list_empty(&cb->cb_per_client)) {
 804                 /* This is the first call, not a restart */
 805                 cb->cb_done = false;
 806                 list_add(&cb->cb_per_client, &clp->cl_callbacks);
 807         }
 808         spin_unlock(&clp->cl_lock);
 809         rpc_call_start(task);
 810 }
 811
 812 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 813 {
 814         struct nfsd4_callback *cb = calldata;
 815         struct nfs4_client *clp = cb->cb_clp;
 816
 817         dprintk("%s: minorversion=%d\n", __func__,
 818                 clp->cl_minorversion);
 819
 820         if (clp->cl_minorversion) {
 821                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 822                 ++clp->cl_cb_session->se_cb_seq_nr;
 823                 clear_bit(0, &clp->cl_cb_slot_busy);
 824                 rpc_wake_up_next(&clp->cl_cb_waitq);
 825                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 826                         clp->cl_cb_session->se_cb_seq_nr);
 827         }
 828
 829         if (clp->cl_cb_client != task->tk_client) {
 830                 /* We're shutting down or changing cl_cb_client; leave
 831                  * it to nfsd4_process_cb_update to restart the call if
 832                  * necessary. */
 833                 return;
 834         }
 835
 836         if (cb->cb_done)
 837                 return;
 838
 839         switch (cb->cb_ops->done(cb, task)) {
 840         case 0:
 841                 task->tk_status = 0;
 842                 rpc_restart_call_prepare(task);
 843                 return;
 844         case 1:
 845                 break;
 846         case -1:
 847                 /* Network partition? */
 848                 nfsd4_mark_cb_down(clp, task->tk_status);
 849                 break;
 850         default:
 851                 BUG();
 852         }
 853         cb->cb_done = true;
 854 }
 855
 856 static void nfsd4_cb_release(void *calldata)
 857 {
 858         struct nfsd4_callback *cb = calldata;
 859         struct nfs4_client *clp = cb->cb_clp;
 860
 861         if (cb->cb_done) {
 862                 spin_lock(&clp->cl_lock);
 863                 list_del(&cb->cb_per_client);
 864                 spin_unlock(&clp->cl_lock);
 865
 866                 cb->cb_ops->release(cb);
 867         }
 868 }
 869
 870 static const struct rpc_call_ops nfsd4_cb_ops = {
 871         .rpc_call_prepare = nfsd4_cb_prepare,
 872         .rpc_call_done = nfsd4_cb_done,
 873         .rpc_release = nfsd4_cb_release,
 874 };
 875
 876 int nfsd4_create_callback_queue(void)
 877 {
 878         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 879         if (!callback_wq)
 880                 return -ENOMEM;
 881         return 0;
 882 }
 883
 884 void nfsd4_destroy_callback_queue(void)
 885 {
 886         destroy_workqueue(callback_wq);
 887 }
 888
 889 /* must be called under the state lock */
 890 void nfsd4_shutdown_callback(struct nfs4_client *clp)
 891 {
 892         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
 893         /*
 894          * Note this won't actually result in a null callback;
 895          * instead, nfsd4_run_cb_null() will detect the killed
 896          * client, destroy the rpc client, and stop:
 897          */
 898         nfsd4_run_cb(&clp->cl_cb_null);
 899         flush_workqueue(callback_wq);
 900 }
 901
 902 /* requires cl_lock: */
 903 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 904 {
 905         struct nfsd4_session *s;
 906         struct nfsd4_conn *c;
 907
 908         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 909                 list_for_each_entry(c, &s->se_conns, cn_persession) {
 910                         if (c->cn_flags & NFS4_CDFC4_BACK)
 911                                 return c;
 912                 }
 913         }
 914         return NULL;
 915 }
 916
 917 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 918 {
 919         struct nfs4_cb_conn conn;
 920         struct nfs4_client *clp = cb->cb_clp;
 921         struct nfsd4_session *ses = NULL;
 922         struct nfsd4_conn *c;
 923         int err;
 924
 925         /*
 926          * This is either an update, or the client dying; in either case,
 927          * kill the old client:
 928          */
 929         if (clp->cl_cb_client) {
 930                 rpc_shutdown_client(clp->cl_cb_client);
 931                 clp->cl_cb_client = NULL;
 932                 put_rpccred(clp->cl_cb_cred);
 933                 clp->cl_cb_cred = NULL;
 934         }
 935         if (clp->cl_cb_conn.cb_xprt) {
 936                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 937                 clp->cl_cb_conn.cb_xprt = NULL;
 938         }
 939         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
 940                 return;
 941         spin_lock(&clp->cl_lock);
 942         /*
 943          * Only serialized callback code is allowed to clear these
 944          * flags; main nfsd code can only set them:
 945          */
 946         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
 947         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 948         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
 949         c = __nfsd4_find_backchannel(clp);
 950         if (c) {
 951                 svc_xprt_get(c->cn_xprt);
 952                 conn.cb_xprt = c->cn_xprt;
 953                 ses = c->cn_session;
 954         }
 955         spin_unlock(&clp->cl_lock);
 956
 957         err = setup_callback_client(clp, &conn, ses);
 958         if (err) {
 959                 nfsd4_mark_cb_down(clp, err);
 960                 return;
 961         }
 962         /* Yay, the callback channel's back! Restart any callbacks: */
 963         list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
 964                 queue_work(callback_wq, &cb->cb_work);
 965 }
 966
 967 static void
 968 nfsd4_run_cb_work(struct work_struct *work)
 969 {
 970         struct nfsd4_callback *cb =
 971                 container_of(work, struct nfsd4_callback, cb_work);
 972         struct nfs4_client *clp = cb->cb_clp;
 973         struct rpc_clnt *clnt;
 974
 975         if (cb->cb_ops && cb->cb_ops->prepare)
 976                 cb->cb_ops->prepare(cb);
 977
 978         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
 979                 nfsd4_process_cb_update(cb);
 980
 981         clnt = clp->cl_cb_client;
 982         if (!clnt) {
 983                 /* Callback channel broken, or client killed; give up: */
 984                 if (cb->cb_ops && cb->cb_ops->release)
 985                         cb->cb_ops->release(cb);
 986                 return;
 987         }
 988         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
 989         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
 990                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
 991 }
 992
 993 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
 994                 struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
 995 {
 996         cb->cb_clp = clp;
 997         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
 998         cb->cb_msg.rpc_argp = cb;
 999         cb->cb_msg.rpc_resp = cb;
1000         cb->cb_ops = ops;
1001         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1002         INIT_LIST_HEAD(&cb->cb_per_client);
1003         cb->cb_done = true;
1004 }
1005
1006 void nfsd4_run_cb(struct nfsd4_callback *cb)
1007 {
1008         queue_work(callback_wq, &cb->cb_work);
1009 }