linux/fs/nfsd/nfs4callback.c
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   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/svc_xprt.h>
  36#include <linux/slab.h>
  37#include "nfsd.h"
  38#include "state.h"
  39#include "netns.h"
  40#include "xdr4cb.h"
  41
  42#define NFSDDBG_FACILITY                NFSDDBG_PROC
  43
  44static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  45
  46#define NFSPROC4_CB_NULL 0
  47#define NFSPROC4_CB_COMPOUND 1
  48
  49/* Index of predefined Linux callback client operations */
  50
  51enum {
  52        NFSPROC4_CLNT_CB_NULL = 0,
  53        NFSPROC4_CLNT_CB_RECALL,
  54        NFSPROC4_CLNT_CB_SEQUENCE,
  55};
  56
  57struct nfs4_cb_compound_hdr {
  58        /* args */
  59        u32             ident;  /* minorversion 0 only */
  60        u32             nops;
  61        __be32          *nops_p;
  62        u32             minorversion;
  63        /* res */
  64        int             status;
  65};
  66
  67/*
  68 * Handle decode buffer overflows out-of-line.
  69 */
  70static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  71{
  72        dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  73                "Remaining buffer length is %tu words.\n",
  74                func, xdr->end - xdr->p);
  75}
  76
  77static __be32 *xdr_encode_empty_array(__be32 *p)
  78{
  79        *p++ = xdr_zero;
  80        return p;
  81}
  82
  83/*
  84 * Encode/decode NFSv4 CB basic data types
  85 *
  86 * Basic NFSv4 callback data types are defined in section 15 of RFC
  87 * 3530: "Network File System (NFS) version 4 Protocol" and section
  88 * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
  89 * 1 Protocol"
  90 */
  91
  92/*
  93 *      nfs_cb_opnum4
  94 *
  95 *      enum nfs_cb_opnum4 {
  96 *              OP_CB_GETATTR           = 3,
  97 *                ...
  98 *      };
  99 */
 100enum nfs_cb_opnum4 {
 101        OP_CB_GETATTR                   = 3,
 102        OP_CB_RECALL                    = 4,
 103        OP_CB_LAYOUTRECALL              = 5,
 104        OP_CB_NOTIFY                    = 6,
 105        OP_CB_PUSH_DELEG                = 7,
 106        OP_CB_RECALL_ANY                = 8,
 107        OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 108        OP_CB_RECALL_SLOT               = 10,
 109        OP_CB_SEQUENCE                  = 11,
 110        OP_CB_WANTS_CANCELLED           = 12,
 111        OP_CB_NOTIFY_LOCK               = 13,
 112        OP_CB_NOTIFY_DEVICEID           = 14,
 113        OP_CB_ILLEGAL                   = 10044
 114};
 115
 116static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 117{
 118        __be32 *p;
 119
 120        p = xdr_reserve_space(xdr, 4);
 121        *p = cpu_to_be32(op);
 122}
 123
 124/*
 125 * nfs_fh4
 126 *
 127 *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 128 */
 129static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 130{
 131        u32 length = fh->fh_size;
 132        __be32 *p;
 133
 134        BUG_ON(length > NFS4_FHSIZE);
 135        p = xdr_reserve_space(xdr, 4 + length);
 136        xdr_encode_opaque(p, &fh->fh_base, length);
 137}
 138
 139/*
 140 * stateid4
 141 *
 142 *      struct stateid4 {
 143 *              uint32_t        seqid;
 144 *              opaque          other[12];
 145 *      };
 146 */
 147static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 148{
 149        __be32 *p;
 150
 151        p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 152        *p++ = cpu_to_be32(sid->si_generation);
 153        xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 154}
 155
 156/*
 157 * sessionid4
 158 *
 159 *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 160 */
 161static void encode_sessionid4(struct xdr_stream *xdr,
 162                              const struct nfsd4_session *session)
 163{
 164        __be32 *p;
 165
 166        p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 167        xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 168                                        NFS4_MAX_SESSIONID_LEN);
 169}
 170
 171/*
 172 * nfsstat4
 173 */
 174static const struct {
 175        int stat;
 176        int errno;
 177} nfs_cb_errtbl[] = {
 178        { NFS4_OK,              0               },
 179        { NFS4ERR_PERM,         -EPERM          },
 180        { NFS4ERR_NOENT,        -ENOENT         },
 181        { NFS4ERR_IO,           -EIO            },
 182        { NFS4ERR_NXIO,         -ENXIO          },
 183        { NFS4ERR_ACCESS,       -EACCES         },
 184        { NFS4ERR_EXIST,        -EEXIST         },
 185        { NFS4ERR_XDEV,         -EXDEV          },
 186        { NFS4ERR_NOTDIR,       -ENOTDIR        },
 187        { NFS4ERR_ISDIR,        -EISDIR         },
 188        { NFS4ERR_INVAL,        -EINVAL         },
 189        { NFS4ERR_FBIG,         -EFBIG          },
 190        { NFS4ERR_NOSPC,        -ENOSPC         },
 191        { NFS4ERR_ROFS,         -EROFS          },
 192        { NFS4ERR_MLINK,        -EMLINK         },
 193        { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 194        { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 195        { NFS4ERR_DQUOT,        -EDQUOT         },
 196        { NFS4ERR_STALE,        -ESTALE         },
 197        { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 198        { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 199        { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 200        { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 201        { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 202        { NFS4ERR_BADTYPE,      -EBADTYPE       },
 203        { NFS4ERR_LOCKED,       -EAGAIN         },
 204        { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 205        { NFS4ERR_SYMLINK,      -ELOOP          },
 206        { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 207        { NFS4ERR_DEADLOCK,     -EDEADLK        },
 208        { -1,                   -EIO            }
 209};
 210
 211/*
 212 * If we cannot translate the error, the recovery routines should
 213 * handle it.
 214 *
 215 * Note: remaining NFSv4 error codes have values > 10000, so should
 216 * not conflict with native Linux error codes.
 217 */
 218static int nfs_cb_stat_to_errno(int status)
 219{
 220        int i;
 221
 222        for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 223                if (nfs_cb_errtbl[i].stat == status)
 224                        return nfs_cb_errtbl[i].errno;
 225        }
 226
 227        dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 228        return -status;
 229}
 230
 231static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
 232                               enum nfsstat4 *status)
 233{
 234        __be32 *p;
 235        u32 op;
 236
 237        p = xdr_inline_decode(xdr, 4 + 4);
 238        if (unlikely(p == NULL))
 239                goto out_overflow;
 240        op = be32_to_cpup(p++);
 241        if (unlikely(op != expected))
 242                goto out_unexpected;
 243        *status = be32_to_cpup(p);
 244        return 0;
 245out_overflow:
 246        print_overflow_msg(__func__, xdr);
 247        return -EIO;
 248out_unexpected:
 249        dprintk("NFSD: Callback server returned operation %d but "
 250                "we issued a request for %d\n", op, expected);
 251        return -EIO;
 252}
 253
 254/*
 255 * CB_COMPOUND4args
 256 *
 257 *      struct CB_COMPOUND4args {
 258 *              utf8str_cs      tag;
 259 *              uint32_t        minorversion;
 260 *              uint32_t        callback_ident;
 261 *              nfs_cb_argop4   argarray<>;
 262 *      };
 263*/
 264static void encode_cb_compound4args(struct xdr_stream *xdr,
 265                                    struct nfs4_cb_compound_hdr *hdr)
 266{
 267        __be32 * p;
 268
 269        p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 270        p = xdr_encode_empty_array(p);          /* empty tag */
 271        *p++ = cpu_to_be32(hdr->minorversion);
 272        *p++ = cpu_to_be32(hdr->ident);
 273
 274        hdr->nops_p = p;
 275        *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 276}
 277
 278/*
 279 * Update argarray element count
 280 */
 281static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 282{
 283        BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 284        *hdr->nops_p = cpu_to_be32(hdr->nops);
 285}
 286
 287/*
 288 * CB_COMPOUND4res
 289 *
 290 *      struct CB_COMPOUND4res {
 291 *              nfsstat4        status;
 292 *              utf8str_cs      tag;
 293 *              nfs_cb_resop4   resarray<>;
 294 *      };
 295 */
 296static int decode_cb_compound4res(struct xdr_stream *xdr,
 297                                  struct nfs4_cb_compound_hdr *hdr)
 298{
 299        u32 length;
 300        __be32 *p;
 301
 302        p = xdr_inline_decode(xdr, 4 + 4);
 303        if (unlikely(p == NULL))
 304                goto out_overflow;
 305        hdr->status = be32_to_cpup(p++);
 306        /* Ignore the tag */
 307        length = be32_to_cpup(p++);
 308        p = xdr_inline_decode(xdr, length + 4);
 309        if (unlikely(p == NULL))
 310                goto out_overflow;
 311        hdr->nops = be32_to_cpup(p);
 312        return 0;
 313out_overflow:
 314        print_overflow_msg(__func__, xdr);
 315        return -EIO;
 316}
 317
 318/*
 319 * CB_RECALL4args
 320 *
 321 *      struct CB_RECALL4args {
 322 *              stateid4        stateid;
 323 *              bool            truncate;
 324 *              nfs_fh4         fh;
 325 *      };
 326 */
 327static void encode_cb_recall4args(struct xdr_stream *xdr,
 328                                  const struct nfs4_delegation *dp,
 329                                  struct nfs4_cb_compound_hdr *hdr)
 330{
 331        __be32 *p;
 332
 333        encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 334        encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 335
 336        p = xdr_reserve_space(xdr, 4);
 337        *p++ = xdr_zero;                        /* truncate */
 338
 339        encode_nfs_fh4(xdr, &dp->dl_fh);
 340
 341        hdr->nops++;
 342}
 343
 344/*
 345 * CB_SEQUENCE4args
 346 *
 347 *      struct CB_SEQUENCE4args {
 348 *              sessionid4              csa_sessionid;
 349 *              sequenceid4             csa_sequenceid;
 350 *              slotid4                 csa_slotid;
 351 *              slotid4                 csa_highest_slotid;
 352 *              bool                    csa_cachethis;
 353 *              referring_call_list4    csa_referring_call_lists<>;
 354 *      };
 355 */
 356static void encode_cb_sequence4args(struct xdr_stream *xdr,
 357                                    const struct nfsd4_callback *cb,
 358                                    struct nfs4_cb_compound_hdr *hdr)
 359{
 360        struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 361        __be32 *p;
 362
 363        if (hdr->minorversion == 0)
 364                return;
 365
 366        encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 367        encode_sessionid4(xdr, session);
 368
 369        p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 370        *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 371        *p++ = xdr_zero;                        /* csa_slotid */
 372        *p++ = xdr_zero;                        /* csa_highest_slotid */
 373        *p++ = xdr_zero;                        /* csa_cachethis */
 374        xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 375
 376        hdr->nops++;
 377}
 378
 379/*
 380 * CB_SEQUENCE4resok
 381 *
 382 *      struct CB_SEQUENCE4resok {
 383 *              sessionid4      csr_sessionid;
 384 *              sequenceid4     csr_sequenceid;
 385 *              slotid4         csr_slotid;
 386 *              slotid4         csr_highest_slotid;
 387 *              slotid4         csr_target_highest_slotid;
 388 *      };
 389 *
 390 *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 391 *      case NFS4_OK:
 392 *              CB_SEQUENCE4resok       csr_resok4;
 393 *      default:
 394 *              void;
 395 *      };
 396 *
 397 * Our current back channel implmentation supports a single backchannel
 398 * with a single slot.
 399 */
 400static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 401                                    struct nfsd4_callback *cb)
 402{
 403        struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 404        struct nfs4_sessionid id;
 405        int status;
 406        __be32 *p;
 407        u32 dummy;
 408
 409        status = -ESERVERFAULT;
 410
 411        /*
 412         * If the server returns different values for sessionID, slotID or
 413         * sequence number, the server is looney tunes.
 414         */
 415        p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 416        if (unlikely(p == NULL))
 417                goto out_overflow;
 418        memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 419        if (memcmp(id.data, session->se_sessionid.data,
 420                                        NFS4_MAX_SESSIONID_LEN) != 0) {
 421                dprintk("NFS: %s Invalid session id\n", __func__);
 422                goto out;
 423        }
 424        p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 425
 426        dummy = be32_to_cpup(p++);
 427        if (dummy != session->se_cb_seq_nr) {
 428                dprintk("NFS: %s Invalid sequence number\n", __func__);
 429                goto out;
 430        }
 431
 432        dummy = be32_to_cpup(p++);
 433        if (dummy != 0) {
 434                dprintk("NFS: %s Invalid slotid\n", __func__);
 435                goto out;
 436        }
 437
 438        /*
 439         * FIXME: process highest slotid and target highest slotid
 440         */
 441        status = 0;
 442out:
 443        if (status)
 444                nfsd4_mark_cb_fault(cb->cb_clp, status);
 445        return status;
 446out_overflow:
 447        print_overflow_msg(__func__, xdr);
 448        return -EIO;
 449}
 450
 451static int decode_cb_sequence4res(struct xdr_stream *xdr,
 452                                  struct nfsd4_callback *cb)
 453{
 454        enum nfsstat4 nfserr;
 455        int status;
 456
 457        if (cb->cb_minorversion == 0)
 458                return 0;
 459
 460        status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
 461        if (unlikely(status))
 462                goto out;
 463        if (unlikely(nfserr != NFS4_OK))
 464                goto out_default;
 465        status = decode_cb_sequence4resok(xdr, cb);
 466out:
 467        return status;
 468out_default:
 469        return nfs_cb_stat_to_errno(nfserr);
 470}
 471
 472/*
 473 * NFSv4.0 and NFSv4.1 XDR encode functions
 474 *
 475 * NFSv4.0 callback argument types are defined in section 15 of RFC
 476 * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 477 * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 478 * Protocol".
 479 */
 480
 481/*
 482 * NB: Without this zero space reservation, callbacks over krb5p fail
 483 */
 484static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 485                                 void *__unused)
 486{
 487        xdr_reserve_space(xdr, 0);
 488}
 489
 490/*
 491 * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 492 */
 493static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 494                                   const struct nfsd4_callback *cb)
 495{
 496        const struct nfs4_delegation *args = cb->cb_op;
 497        struct nfs4_cb_compound_hdr hdr = {
 498                .ident = cb->cb_clp->cl_cb_ident,
 499                .minorversion = cb->cb_minorversion,
 500        };
 501
 502        encode_cb_compound4args(xdr, &hdr);
 503        encode_cb_sequence4args(xdr, cb, &hdr);
 504        encode_cb_recall4args(xdr, args, &hdr);
 505        encode_cb_nops(&hdr);
 506}
 507
 508
 509/*
 510 * NFSv4.0 and NFSv4.1 XDR decode functions
 511 *
 512 * NFSv4.0 callback result types are defined in section 15 of RFC
 513 * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 514 * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 515 * Protocol".
 516 */
 517
 518static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 519                                void *__unused)
 520{
 521        return 0;
 522}
 523
 524/*
 525 * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 526 */
 527static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 528                                  struct xdr_stream *xdr,
 529                                  struct nfsd4_callback *cb)
 530{
 531        struct nfs4_cb_compound_hdr hdr;
 532        enum nfsstat4 nfserr;
 533        int status;
 534
 535        status = decode_cb_compound4res(xdr, &hdr);
 536        if (unlikely(status))
 537                goto out;
 538
 539        if (cb != NULL) {
 540                status = decode_cb_sequence4res(xdr, cb);
 541                if (unlikely(status))
 542                        goto out;
 543        }
 544
 545        status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
 546        if (unlikely(status))
 547                goto out;
 548        if (unlikely(nfserr != NFS4_OK))
 549                status = nfs_cb_stat_to_errno(nfserr);
 550out:
 551        return status;
 552}
 553
 554/*
 555 * RPC procedure tables
 556 */
 557#define PROC(proc, call, argtype, restype)                              \
 558[NFSPROC4_CLNT_##proc] = {                                              \
 559        .p_proc    = NFSPROC4_CB_##call,                                \
 560        .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 561        .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 562        .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 563        .p_replen  = NFS4_dec_##restype##_sz,                           \
 564        .p_statidx = NFSPROC4_CB_##call,                                \
 565        .p_name    = #proc,                                             \
 566}
 567
 568static struct rpc_procinfo nfs4_cb_procedures[] = {
 569        PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 570        PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 571};
 572
 573static struct rpc_version nfs_cb_version4 = {
 574/*
 575 * Note on the callback rpc program version number: despite language in rfc
 576 * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 577 * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 578 * in practice that appears to be what implementations use.  The section
 579 * 18.36.3 language is expected to be fixed in an erratum.
 580 */
 581        .number                 = 1,
 582        .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 583        .procs                  = nfs4_cb_procedures
 584};
 585
 586static const struct rpc_version *nfs_cb_version[] = {
 587        &nfs_cb_version4,
 588};
 589
 590static const struct rpc_program cb_program;
 591
 592static struct rpc_stat cb_stats = {
 593        .program                = &cb_program
 594};
 595
 596#define NFS4_CALLBACK 0x40000000
 597static const struct rpc_program cb_program = {
 598        .name                   = "nfs4_cb",
 599        .number                 = NFS4_CALLBACK,
 600        .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 601        .version                = nfs_cb_version,
 602        .stats                  = &cb_stats,
 603        .pipe_dir_name          = "nfsd4_cb",
 604};
 605
 606static int max_cb_time(struct net *net)
 607{
 608        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 609        return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 610}
 611
 612static struct rpc_cred *callback_cred;
 613
 614int set_callback_cred(void)
 615{
 616        if (callback_cred)
 617                return 0;
 618        callback_cred = rpc_lookup_machine_cred("nfs");
 619        if (!callback_cred)
 620                return -ENOMEM;
 621        return 0;
 622}
 623
 624static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 625{
 626        if (clp->cl_minorversion == 0) {
 627                return get_rpccred(callback_cred);
 628        } else {
 629                struct rpc_auth *auth = client->cl_auth;
 630                struct auth_cred acred = {};
 631
 632                acred.uid = ses->se_cb_sec.uid;
 633                acred.gid = ses->se_cb_sec.gid;
 634                return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
 635        }
 636}
 637
 638static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 639{
 640        struct rpc_timeout      timeparms = {
 641                .to_initval     = max_cb_time(clp->net),
 642                .to_retries     = 0,
 643        };
 644        struct rpc_create_args args = {
 645                .net            = clp->net,
 646                .address        = (struct sockaddr *) &conn->cb_addr,
 647                .addrsize       = conn->cb_addrlen,
 648                .saddress       = (struct sockaddr *) &conn->cb_saddr,
 649                .timeout        = &timeparms,
 650                .program        = &cb_program,
 651                .version        = 0,
 652                .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 653        };
 654        struct rpc_clnt *client;
 655        struct rpc_cred *cred;
 656
 657        if (clp->cl_minorversion == 0) {
 658                if (!clp->cl_cred.cr_principal &&
 659                                (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 660                        return -EINVAL;
 661                args.client_name = clp->cl_cred.cr_principal;
 662                args.prognumber = conn->cb_prog,
 663                args.protocol = XPRT_TRANSPORT_TCP;
 664                args.authflavor = clp->cl_cred.cr_flavor;
 665                clp->cl_cb_ident = conn->cb_ident;
 666        } else {
 667                if (!conn->cb_xprt)
 668                        return -EINVAL;
 669                clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 670                clp->cl_cb_session = ses;
 671                args.bc_xprt = conn->cb_xprt;
 672                args.prognumber = clp->cl_cb_session->se_cb_prog;
 673                args.protocol = XPRT_TRANSPORT_BC_TCP;
 674                args.authflavor = ses->se_cb_sec.flavor;
 675        }
 676        /* Create RPC client */
 677        client = rpc_create(&args);
 678        if (IS_ERR(client)) {
 679                dprintk("NFSD: couldn't create callback client: %ld\n",
 680                        PTR_ERR(client));
 681                return PTR_ERR(client);
 682        }
 683        cred = get_backchannel_cred(clp, client, ses);
 684        if (IS_ERR(cred)) {
 685                rpc_shutdown_client(client);
 686                return PTR_ERR(cred);
 687        }
 688        clp->cl_cb_client = client;
 689        clp->cl_cb_cred = cred;
 690        return 0;
 691}
 692
 693static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 694{
 695        dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 696                (int)clp->cl_name.len, clp->cl_name.data, reason);
 697}
 698
 699static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 700{
 701        clp->cl_cb_state = NFSD4_CB_DOWN;
 702        warn_no_callback_path(clp, reason);
 703}
 704
 705static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 706{
 707        clp->cl_cb_state = NFSD4_CB_FAULT;
 708        warn_no_callback_path(clp, reason);
 709}
 710
 711static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 712{
 713        struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 714
 715        if (task->tk_status)
 716                nfsd4_mark_cb_down(clp, task->tk_status);
 717        else
 718                clp->cl_cb_state = NFSD4_CB_UP;
 719}
 720
 721static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 722        /* XXX: release method to ensure we set the cb channel down if
 723         * necessary on early failure? */
 724        .rpc_call_done = nfsd4_cb_probe_done,
 725};
 726
 727static struct workqueue_struct *callback_wq;
 728
 729static void run_nfsd4_cb(struct nfsd4_callback *cb)
 730{
 731        queue_work(callback_wq, &cb->cb_work);
 732}
 733
 734static void do_probe_callback(struct nfs4_client *clp)
 735{
 736        struct nfsd4_callback *cb = &clp->cl_cb_null;
 737
 738        cb->cb_op = NULL;
 739        cb->cb_clp = clp;
 740
 741        cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
 742        cb->cb_msg.rpc_argp = NULL;
 743        cb->cb_msg.rpc_resp = NULL;
 744
 745        cb->cb_ops = &nfsd4_cb_probe_ops;
 746
 747        run_nfsd4_cb(cb);
 748}
 749
 750/*
 751 * Poke the callback thread to process any updates to the callback
 752 * parameters, and send a null probe.
 753 */
 754void nfsd4_probe_callback(struct nfs4_client *clp)
 755{
 756        clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 757        set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 758        do_probe_callback(clp);
 759}
 760
 761void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 762{
 763        nfsd4_probe_callback(clp);
 764        flush_workqueue(callback_wq);
 765}
 766
 767void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 768{
 769        clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 770        spin_lock(&clp->cl_lock);
 771        memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 772        spin_unlock(&clp->cl_lock);
 773}
 774
 775/*
 776 * There's currently a single callback channel slot.
 777 * If the slot is available, then mark it busy.  Otherwise, set the
 778 * thread for sleeping on the callback RPC wait queue.
 779 */
 780static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 781{
 782        if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 783                rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 784                dprintk("%s slot is busy\n", __func__);
 785                return false;
 786        }
 787        return true;
 788}
 789
 790/*
 791 * TODO: cb_sequence should support referring call lists, cachethis, multiple
 792 * slots, and mark callback channel down on communication errors.
 793 */
 794static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 795{
 796        struct nfsd4_callback *cb = calldata;
 797        struct nfs4_client *clp = cb->cb_clp;
 798        u32 minorversion = clp->cl_minorversion;
 799
 800        cb->cb_minorversion = minorversion;
 801        if (minorversion) {
 802                if (!nfsd41_cb_get_slot(clp, task))
 803                        return;
 804        }
 805        spin_lock(&clp->cl_lock);
 806        if (list_empty(&cb->cb_per_client)) {
 807                /* This is the first call, not a restart */
 808                cb->cb_done = false;
 809                list_add(&cb->cb_per_client, &clp->cl_callbacks);
 810        }
 811        spin_unlock(&clp->cl_lock);
 812        rpc_call_start(task);
 813}
 814
 815static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 816{
 817        struct nfsd4_callback *cb = calldata;
 818        struct nfs4_client *clp = cb->cb_clp;
 819
 820        dprintk("%s: minorversion=%d\n", __func__,
 821                clp->cl_minorversion);
 822
 823        if (clp->cl_minorversion) {
 824                /* No need for lock, access serialized in nfsd4_cb_prepare */
 825                ++clp->cl_cb_session->se_cb_seq_nr;
 826                clear_bit(0, &clp->cl_cb_slot_busy);
 827                rpc_wake_up_next(&clp->cl_cb_waitq);
 828                dprintk("%s: freed slot, new seqid=%d\n", __func__,
 829                        clp->cl_cb_session->se_cb_seq_nr);
 830
 831                /* We're done looking into the sequence information */
 832                task->tk_msg.rpc_resp = NULL;
 833        }
 834}
 835
 836
 837static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 838{
 839        struct nfsd4_callback *cb = calldata;
 840        struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 841        struct nfs4_client *clp = cb->cb_clp;
 842        struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 843
 844        nfsd4_cb_done(task, calldata);
 845
 846        if (current_rpc_client != task->tk_client) {
 847                /* We're shutting down or changing cl_cb_client; leave
 848                 * it to nfsd4_process_cb_update to restart the call if
 849                 * necessary. */
 850                return;
 851        }
 852
 853        if (cb->cb_done)
 854                return;
 855        switch (task->tk_status) {
 856        case 0:
 857                cb->cb_done = true;
 858                return;
 859        case -EBADHANDLE:
 860        case -NFS4ERR_BAD_STATEID:
 861                /* Race: client probably got cb_recall
 862                 * before open reply granting delegation */
 863                break;
 864        default:
 865                /* Network partition? */
 866                nfsd4_mark_cb_down(clp, task->tk_status);
 867        }
 868        if (dp->dl_retries--) {
 869                rpc_delay(task, 2*HZ);
 870                task->tk_status = 0;
 871                rpc_restart_call_prepare(task);
 872                return;
 873        }
 874        nfsd4_mark_cb_down(clp, task->tk_status);
 875        cb->cb_done = true;
 876}
 877
 878static void nfsd4_cb_recall_release(void *calldata)
 879{
 880        struct nfsd4_callback *cb = calldata;
 881        struct nfs4_client *clp = cb->cb_clp;
 882        struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 883
 884        if (cb->cb_done) {
 885                spin_lock(&clp->cl_lock);
 886                list_del(&cb->cb_per_client);
 887                spin_unlock(&clp->cl_lock);
 888                nfs4_put_delegation(dp);
 889        }
 890}
 891
 892static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 893        .rpc_call_prepare = nfsd4_cb_prepare,
 894        .rpc_call_done = nfsd4_cb_recall_done,
 895        .rpc_release = nfsd4_cb_recall_release,
 896};
 897
 898int nfsd4_create_callback_queue(void)
 899{
 900        callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 901        if (!callback_wq)
 902                return -ENOMEM;
 903        return 0;
 904}
 905
 906void nfsd4_destroy_callback_queue(void)
 907{
 908        destroy_workqueue(callback_wq);
 909}
 910
 911/* must be called under the state lock */
 912void nfsd4_shutdown_callback(struct nfs4_client *clp)
 913{
 914        set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
 915        /*
 916         * Note this won't actually result in a null callback;
 917         * instead, nfsd4_do_callback_rpc() will detect the killed
 918         * client, destroy the rpc client, and stop:
 919         */
 920        do_probe_callback(clp);
 921        flush_workqueue(callback_wq);
 922}
 923
 924static void nfsd4_release_cb(struct nfsd4_callback *cb)
 925{
 926        if (cb->cb_ops->rpc_release)
 927                cb->cb_ops->rpc_release(cb);
 928}
 929
 930/* requires cl_lock: */
 931static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 932{
 933        struct nfsd4_session *s;
 934        struct nfsd4_conn *c;
 935
 936        list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 937                list_for_each_entry(c, &s->se_conns, cn_persession) {
 938                        if (c->cn_flags & NFS4_CDFC4_BACK)
 939                                return c;
 940                }
 941        }
 942        return NULL;
 943}
 944
 945static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 946{
 947        struct nfs4_cb_conn conn;
 948        struct nfs4_client *clp = cb->cb_clp;
 949        struct nfsd4_session *ses = NULL;
 950        struct nfsd4_conn *c;
 951        int err;
 952
 953        /*
 954         * This is either an update, or the client dying; in either case,
 955         * kill the old client:
 956         */
 957        if (clp->cl_cb_client) {
 958                rpc_shutdown_client(clp->cl_cb_client);
 959                clp->cl_cb_client = NULL;
 960                put_rpccred(clp->cl_cb_cred);
 961                clp->cl_cb_cred = NULL;
 962        }
 963        if (clp->cl_cb_conn.cb_xprt) {
 964                svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 965                clp->cl_cb_conn.cb_xprt = NULL;
 966        }
 967        if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
 968                return;
 969        spin_lock(&clp->cl_lock);
 970        /*
 971         * Only serialized callback code is allowed to clear these
 972         * flags; main nfsd code can only set them:
 973         */
 974        BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
 975        clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 976        memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
 977        c = __nfsd4_find_backchannel(clp);
 978        if (c) {
 979                svc_xprt_get(c->cn_xprt);
 980                conn.cb_xprt = c->cn_xprt;
 981                ses = c->cn_session;
 982        }
 983        spin_unlock(&clp->cl_lock);
 984
 985        err = setup_callback_client(clp, &conn, ses);
 986        if (err) {
 987                nfsd4_mark_cb_down(clp, err);
 988                return;
 989        }
 990        /* Yay, the callback channel's back! Restart any callbacks: */
 991        list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
 992                run_nfsd4_cb(cb);
 993}
 994
 995static void nfsd4_do_callback_rpc(struct work_struct *w)
 996{
 997        struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
 998        struct nfs4_client *clp = cb->cb_clp;
 999        struct rpc_clnt *clnt;
1000
1001        if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1002                nfsd4_process_cb_update(cb);
1003
1004        clnt = clp->cl_cb_client;
1005        if (!clnt) {
1006                /* Callback channel broken, or client killed; give up: */
1007                nfsd4_release_cb(cb);
1008                return;
1009        }
1010        cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1011        rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1012                        cb->cb_ops, cb);
1013}
1014
1015void nfsd4_init_callback(struct nfsd4_callback *cb)
1016{
1017        INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc);
1018}
1019
1020void nfsd4_cb_recall(struct nfs4_delegation *dp)
1021{
1022        struct nfsd4_callback *cb = &dp->dl_recall;
1023        struct nfs4_client *clp = dp->dl_stid.sc_client;
1024
1025        dp->dl_retries = 1;
1026        cb->cb_op = dp;
1027        cb->cb_clp = clp;
1028        cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1029        cb->cb_msg.rpc_argp = cb;
1030        cb->cb_msg.rpc_resp = cb;
1031
1032        cb->cb_ops = &nfsd4_cb_recall_ops;
1033
1034        INIT_LIST_HEAD(&cb->cb_per_client);
1035        cb->cb_done = true;
1036
1037        run_nfsd4_cb(&dp->dl_recall);
1038}
1039
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