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/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 "trace.h"
  42#include "xdr4cb.h"
  43#include "xdr4.h"
  44
  45#define NFSDDBG_FACILITY                NFSDDBG_PROC
  46
  47static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  48
  49#define NFSPROC4_CB_NULL 0
  50#define NFSPROC4_CB_COMPOUND 1
  51
  52/* Index of predefined Linux callback client operations */
  53
  54struct nfs4_cb_compound_hdr {
  55        /* args */
  56        u32             ident;  /* minorversion 0 only */
  57        u32             nops;
  58        __be32          *nops_p;
  59        u32             minorversion;
  60        /* res */
  61        int             status;
  62};
  63
  64static __be32 *xdr_encode_empty_array(__be32 *p)
  65{
  66        *p++ = xdr_zero;
  67        return p;
  68}
  69
  70/*
  71 * Encode/decode NFSv4 CB basic data types
  72 *
  73 * Basic NFSv4 callback data types are defined in section 15 of RFC
  74 * 3530: "Network File System (NFS) version 4 Protocol" and section
  75 * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
  76 * 1 Protocol"
  77 */
  78
  79/*
  80 *      nfs_cb_opnum4
  81 *
  82 *      enum nfs_cb_opnum4 {
  83 *              OP_CB_GETATTR           = 3,
  84 *                ...
  85 *      };
  86 */
  87enum nfs_cb_opnum4 {
  88        OP_CB_GETATTR                   = 3,
  89        OP_CB_RECALL                    = 4,
  90        OP_CB_LAYOUTRECALL              = 5,
  91        OP_CB_NOTIFY                    = 6,
  92        OP_CB_PUSH_DELEG                = 7,
  93        OP_CB_RECALL_ANY                = 8,
  94        OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
  95        OP_CB_RECALL_SLOT               = 10,
  96        OP_CB_SEQUENCE                  = 11,
  97        OP_CB_WANTS_CANCELLED           = 12,
  98        OP_CB_NOTIFY_LOCK               = 13,
  99        OP_CB_NOTIFY_DEVICEID           = 14,
 100        OP_CB_OFFLOAD                   = 15,
 101        OP_CB_ILLEGAL                   = 10044
 102};
 103
 104static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 105{
 106        __be32 *p;
 107
 108        p = xdr_reserve_space(xdr, 4);
 109        *p = cpu_to_be32(op);
 110}
 111
 112/*
 113 * nfs_fh4
 114 *
 115 *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 116 */
 117static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 118{
 119        u32 length = fh->fh_size;
 120        __be32 *p;
 121
 122        BUG_ON(length > NFS4_FHSIZE);
 123        p = xdr_reserve_space(xdr, 4 + length);
 124        xdr_encode_opaque(p, &fh->fh_base, length);
 125}
 126
 127/*
 128 * stateid4
 129 *
 130 *      struct stateid4 {
 131 *              uint32_t        seqid;
 132 *              opaque          other[12];
 133 *      };
 134 */
 135static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 136{
 137        __be32 *p;
 138
 139        p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 140        *p++ = cpu_to_be32(sid->si_generation);
 141        xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 142}
 143
 144/*
 145 * sessionid4
 146 *
 147 *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 148 */
 149static void encode_sessionid4(struct xdr_stream *xdr,
 150                              const struct nfsd4_session *session)
 151{
 152        __be32 *p;
 153
 154        p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 155        xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 156                                        NFS4_MAX_SESSIONID_LEN);
 157}
 158
 159/*
 160 * nfsstat4
 161 */
 162static const struct {
 163        int stat;
 164        int errno;
 165} nfs_cb_errtbl[] = {
 166        { NFS4_OK,              0               },
 167        { NFS4ERR_PERM,         -EPERM          },
 168        { NFS4ERR_NOENT,        -ENOENT         },
 169        { NFS4ERR_IO,           -EIO            },
 170        { NFS4ERR_NXIO,         -ENXIO          },
 171        { NFS4ERR_ACCESS,       -EACCES         },
 172        { NFS4ERR_EXIST,        -EEXIST         },
 173        { NFS4ERR_XDEV,         -EXDEV          },
 174        { NFS4ERR_NOTDIR,       -ENOTDIR        },
 175        { NFS4ERR_ISDIR,        -EISDIR         },
 176        { NFS4ERR_INVAL,        -EINVAL         },
 177        { NFS4ERR_FBIG,         -EFBIG          },
 178        { NFS4ERR_NOSPC,        -ENOSPC         },
 179        { NFS4ERR_ROFS,         -EROFS          },
 180        { NFS4ERR_MLINK,        -EMLINK         },
 181        { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 182        { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 183        { NFS4ERR_DQUOT,        -EDQUOT         },
 184        { NFS4ERR_STALE,        -ESTALE         },
 185        { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 186        { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 187        { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 188        { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 189        { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 190        { NFS4ERR_BADTYPE,      -EBADTYPE       },
 191        { NFS4ERR_LOCKED,       -EAGAIN         },
 192        { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 193        { NFS4ERR_SYMLINK,      -ELOOP          },
 194        { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 195        { NFS4ERR_DEADLOCK,     -EDEADLK        },
 196        { -1,                   -EIO            }
 197};
 198
 199/*
 200 * If we cannot translate the error, the recovery routines should
 201 * handle it.
 202 *
 203 * Note: remaining NFSv4 error codes have values > 10000, so should
 204 * not conflict with native Linux error codes.
 205 */
 206static int nfs_cb_stat_to_errno(int status)
 207{
 208        int i;
 209
 210        for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 211                if (nfs_cb_errtbl[i].stat == status)
 212                        return nfs_cb_errtbl[i].errno;
 213        }
 214
 215        dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 216        return -status;
 217}
 218
 219static int decode_cb_op_status(struct xdr_stream *xdr,
 220                               enum nfs_cb_opnum4 expected, int *status)
 221{
 222        __be32 *p;
 223        u32 op;
 224
 225        p = xdr_inline_decode(xdr, 4 + 4);
 226        if (unlikely(p == NULL))
 227                goto out_overflow;
 228        op = be32_to_cpup(p++);
 229        if (unlikely(op != expected))
 230                goto out_unexpected;
 231        *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 232        return 0;
 233out_overflow:
 234        return -EIO;
 235out_unexpected:
 236        dprintk("NFSD: Callback server returned operation %d but "
 237                "we issued a request for %d\n", op, expected);
 238        return -EIO;
 239}
 240
 241/*
 242 * CB_COMPOUND4args
 243 *
 244 *      struct CB_COMPOUND4args {
 245 *              utf8str_cs      tag;
 246 *              uint32_t        minorversion;
 247 *              uint32_t        callback_ident;
 248 *              nfs_cb_argop4   argarray<>;
 249 *      };
 250*/
 251static void encode_cb_compound4args(struct xdr_stream *xdr,
 252                                    struct nfs4_cb_compound_hdr *hdr)
 253{
 254        __be32 * p;
 255
 256        p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 257        p = xdr_encode_empty_array(p);          /* empty tag */
 258        *p++ = cpu_to_be32(hdr->minorversion);
 259        *p++ = cpu_to_be32(hdr->ident);
 260
 261        hdr->nops_p = p;
 262        *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 263}
 264
 265/*
 266 * Update argarray element count
 267 */
 268static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 269{
 270        BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 271        *hdr->nops_p = cpu_to_be32(hdr->nops);
 272}
 273
 274/*
 275 * CB_COMPOUND4res
 276 *
 277 *      struct CB_COMPOUND4res {
 278 *              nfsstat4        status;
 279 *              utf8str_cs      tag;
 280 *              nfs_cb_resop4   resarray<>;
 281 *      };
 282 */
 283static int decode_cb_compound4res(struct xdr_stream *xdr,
 284                                  struct nfs4_cb_compound_hdr *hdr)
 285{
 286        u32 length;
 287        __be32 *p;
 288
 289        p = xdr_inline_decode(xdr, 4 + 4);
 290        if (unlikely(p == NULL))
 291                goto out_overflow;
 292        hdr->status = be32_to_cpup(p++);
 293        /* Ignore the tag */
 294        length = be32_to_cpup(p++);
 295        p = xdr_inline_decode(xdr, length + 4);
 296        if (unlikely(p == NULL))
 297                goto out_overflow;
 298        p += XDR_QUADLEN(length);
 299        hdr->nops = be32_to_cpup(p);
 300        return 0;
 301out_overflow:
 302        return -EIO;
 303}
 304
 305/*
 306 * CB_RECALL4args
 307 *
 308 *      struct CB_RECALL4args {
 309 *              stateid4        stateid;
 310 *              bool            truncate;
 311 *              nfs_fh4         fh;
 312 *      };
 313 */
 314static void encode_cb_recall4args(struct xdr_stream *xdr,
 315                                  const struct nfs4_delegation *dp,
 316                                  struct nfs4_cb_compound_hdr *hdr)
 317{
 318        __be32 *p;
 319
 320        encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 321        encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 322
 323        p = xdr_reserve_space(xdr, 4);
 324        *p++ = xdr_zero;                        /* truncate */
 325
 326        encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 327
 328        hdr->nops++;
 329}
 330
 331/*
 332 * CB_SEQUENCE4args
 333 *
 334 *      struct CB_SEQUENCE4args {
 335 *              sessionid4              csa_sessionid;
 336 *              sequenceid4             csa_sequenceid;
 337 *              slotid4                 csa_slotid;
 338 *              slotid4                 csa_highest_slotid;
 339 *              bool                    csa_cachethis;
 340 *              referring_call_list4    csa_referring_call_lists<>;
 341 *      };
 342 */
 343static void encode_cb_sequence4args(struct xdr_stream *xdr,
 344                                    const struct nfsd4_callback *cb,
 345                                    struct nfs4_cb_compound_hdr *hdr)
 346{
 347        struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 348        __be32 *p;
 349
 350        if (hdr->minorversion == 0)
 351                return;
 352
 353        encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 354        encode_sessionid4(xdr, session);
 355
 356        p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 357        *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 358        *p++ = xdr_zero;                        /* csa_slotid */
 359        *p++ = xdr_zero;                        /* csa_highest_slotid */
 360        *p++ = xdr_zero;                        /* csa_cachethis */
 361        xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 362
 363        hdr->nops++;
 364}
 365
 366/*
 367 * CB_SEQUENCE4resok
 368 *
 369 *      struct CB_SEQUENCE4resok {
 370 *              sessionid4      csr_sessionid;
 371 *              sequenceid4     csr_sequenceid;
 372 *              slotid4         csr_slotid;
 373 *              slotid4         csr_highest_slotid;
 374 *              slotid4         csr_target_highest_slotid;
 375 *      };
 376 *
 377 *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 378 *      case NFS4_OK:
 379 *              CB_SEQUENCE4resok       csr_resok4;
 380 *      default:
 381 *              void;
 382 *      };
 383 *
 384 * Our current back channel implmentation supports a single backchannel
 385 * with a single slot.
 386 */
 387static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 388                                    struct nfsd4_callback *cb)
 389{
 390        struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 391        int status = -ESERVERFAULT;
 392        __be32 *p;
 393        u32 dummy;
 394
 395        /*
 396         * If the server returns different values for sessionID, slotID or
 397         * sequence number, the server is looney tunes.
 398         */
 399        p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 400        if (unlikely(p == NULL))
 401                goto out_overflow;
 402
 403        if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 404                dprintk("NFS: %s Invalid session id\n", __func__);
 405                goto out;
 406        }
 407        p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 408
 409        dummy = be32_to_cpup(p++);
 410        if (dummy != session->se_cb_seq_nr) {
 411                dprintk("NFS: %s Invalid sequence number\n", __func__);
 412                goto out;
 413        }
 414
 415        dummy = be32_to_cpup(p++);
 416        if (dummy != 0) {
 417                dprintk("NFS: %s Invalid slotid\n", __func__);
 418                goto out;
 419        }
 420
 421        /*
 422         * FIXME: process highest slotid and target highest slotid
 423         */
 424        status = 0;
 425out:
 426        cb->cb_seq_status = status;
 427        return status;
 428out_overflow:
 429        status = -EIO;
 430        goto out;
 431}
 432
 433static int decode_cb_sequence4res(struct xdr_stream *xdr,
 434                                  struct nfsd4_callback *cb)
 435{
 436        int status;
 437
 438        if (cb->cb_clp->cl_minorversion == 0)
 439                return 0;
 440
 441        status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 442        if (unlikely(status || cb->cb_seq_status))
 443                return status;
 444
 445        return decode_cb_sequence4resok(xdr, cb);
 446}
 447
 448/*
 449 * NFSv4.0 and NFSv4.1 XDR encode functions
 450 *
 451 * NFSv4.0 callback argument types are defined in section 15 of RFC
 452 * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 453 * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 454 * Protocol".
 455 */
 456
 457/*
 458 * NB: Without this zero space reservation, callbacks over krb5p fail
 459 */
 460static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 461                                 const void *__unused)
 462{
 463        xdr_reserve_space(xdr, 0);
 464}
 465
 466/*
 467 * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 468 */
 469static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 470                                   const void *data)
 471{
 472        const struct nfsd4_callback *cb = data;
 473        const struct nfs4_delegation *dp = cb_to_delegation(cb);
 474        struct nfs4_cb_compound_hdr hdr = {
 475                .ident = cb->cb_clp->cl_cb_ident,
 476                .minorversion = cb->cb_clp->cl_minorversion,
 477        };
 478
 479        encode_cb_compound4args(xdr, &hdr);
 480        encode_cb_sequence4args(xdr, cb, &hdr);
 481        encode_cb_recall4args(xdr, dp, &hdr);
 482        encode_cb_nops(&hdr);
 483}
 484
 485
 486/*
 487 * NFSv4.0 and NFSv4.1 XDR decode functions
 488 *
 489 * NFSv4.0 callback result types are defined in section 15 of RFC
 490 * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 491 * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 492 * Protocol".
 493 */
 494
 495static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 496                                void *__unused)
 497{
 498        return 0;
 499}
 500
 501/*
 502 * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 503 */
 504static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 505                                  struct xdr_stream *xdr,
 506                                  void *data)
 507{
 508        struct nfsd4_callback *cb = data;
 509        struct nfs4_cb_compound_hdr hdr;
 510        int status;
 511
 512        status = decode_cb_compound4res(xdr, &hdr);
 513        if (unlikely(status))
 514                return status;
 515
 516        status = decode_cb_sequence4res(xdr, cb);
 517        if (unlikely(status || cb->cb_seq_status))
 518                return status;
 519
 520        return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 521}
 522
 523#ifdef CONFIG_NFSD_PNFS
 524/*
 525 * CB_LAYOUTRECALL4args
 526 *
 527 *      struct layoutrecall_file4 {
 528 *              nfs_fh4         lor_fh;
 529 *              offset4         lor_offset;
 530 *              length4         lor_length;
 531 *              stateid4        lor_stateid;
 532 *      };
 533 *
 534 *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 535 *      case LAYOUTRECALL4_FILE:
 536 *              layoutrecall_file4 lor_layout;
 537 *      case LAYOUTRECALL4_FSID:
 538 *              fsid4              lor_fsid;
 539 *      case LAYOUTRECALL4_ALL:
 540 *              void;
 541 *      };
 542 *
 543 *      struct CB_LAYOUTRECALL4args {
 544 *              layouttype4             clora_type;
 545 *              layoutiomode4           clora_iomode;
 546 *              bool                    clora_changed;
 547 *              layoutrecall4           clora_recall;
 548 *      };
 549 */
 550static void encode_cb_layout4args(struct xdr_stream *xdr,
 551                                  const struct nfs4_layout_stateid *ls,
 552                                  struct nfs4_cb_compound_hdr *hdr)
 553{
 554        __be32 *p;
 555
 556        BUG_ON(hdr->minorversion == 0);
 557
 558        p = xdr_reserve_space(xdr, 5 * 4);
 559        *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 560        *p++ = cpu_to_be32(ls->ls_layout_type);
 561        *p++ = cpu_to_be32(IOMODE_ANY);
 562        *p++ = cpu_to_be32(1);
 563        *p = cpu_to_be32(RETURN_FILE);
 564
 565        encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 566
 567        p = xdr_reserve_space(xdr, 2 * 8);
 568        p = xdr_encode_hyper(p, 0);
 569        xdr_encode_hyper(p, NFS4_MAX_UINT64);
 570
 571        encode_stateid4(xdr, &ls->ls_recall_sid);
 572
 573        hdr->nops++;
 574}
 575
 576static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 577                                   struct xdr_stream *xdr,
 578                                   const void *data)
 579{
 580        const struct nfsd4_callback *cb = data;
 581        const struct nfs4_layout_stateid *ls =
 582                container_of(cb, struct nfs4_layout_stateid, ls_recall);
 583        struct nfs4_cb_compound_hdr hdr = {
 584                .ident = 0,
 585                .minorversion = cb->cb_clp->cl_minorversion,
 586        };
 587
 588        encode_cb_compound4args(xdr, &hdr);
 589        encode_cb_sequence4args(xdr, cb, &hdr);
 590        encode_cb_layout4args(xdr, ls, &hdr);
 591        encode_cb_nops(&hdr);
 592}
 593
 594static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 595                                  struct xdr_stream *xdr,
 596                                  void *data)
 597{
 598        struct nfsd4_callback *cb = data;
 599        struct nfs4_cb_compound_hdr hdr;
 600        int status;
 601
 602        status = decode_cb_compound4res(xdr, &hdr);
 603        if (unlikely(status))
 604                return status;
 605
 606        status = decode_cb_sequence4res(xdr, cb);
 607        if (unlikely(status || cb->cb_seq_status))
 608                return status;
 609
 610        return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 611}
 612#endif /* CONFIG_NFSD_PNFS */
 613
 614static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
 615{
 616        __be32  *p;
 617
 618        p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
 619        p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
 620        xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
 621}
 622
 623static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 624                                        struct xdr_stream *xdr,
 625                                        const void *data)
 626{
 627        const struct nfsd4_callback *cb = data;
 628        const struct nfsd4_blocked_lock *nbl =
 629                container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
 630        struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
 631        struct nfs4_cb_compound_hdr hdr = {
 632                .ident = 0,
 633                .minorversion = cb->cb_clp->cl_minorversion,
 634        };
 635
 636        __be32 *p;
 637
 638        BUG_ON(hdr.minorversion == 0);
 639
 640        encode_cb_compound4args(xdr, &hdr);
 641        encode_cb_sequence4args(xdr, cb, &hdr);
 642
 643        p = xdr_reserve_space(xdr, 4);
 644        *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
 645        encode_nfs_fh4(xdr, &nbl->nbl_fh);
 646        encode_stateowner(xdr, &lo->lo_owner);
 647        hdr.nops++;
 648
 649        encode_cb_nops(&hdr);
 650}
 651
 652static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 653                                        struct xdr_stream *xdr,
 654                                        void *data)
 655{
 656        struct nfsd4_callback *cb = data;
 657        struct nfs4_cb_compound_hdr hdr;
 658        int status;
 659
 660        status = decode_cb_compound4res(xdr, &hdr);
 661        if (unlikely(status))
 662                return status;
 663
 664        status = decode_cb_sequence4res(xdr, cb);
 665        if (unlikely(status || cb->cb_seq_status))
 666                return status;
 667
 668        return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
 669}
 670
 671/*
 672 * struct write_response4 {
 673 *      stateid4        wr_callback_id<1>;
 674 *      length4         wr_count;
 675 *      stable_how4     wr_committed;
 676 *      verifier4       wr_writeverf;
 677 * };
 678 * union offload_info4 switch (nfsstat4 coa_status) {
 679 *      case NFS4_OK:
 680 *              write_response4 coa_resok4;
 681 *      default:
 682 *      length4         coa_bytes_copied;
 683 * };
 684 * struct CB_OFFLOAD4args {
 685 *      nfs_fh4         coa_fh;
 686 *      stateid4        coa_stateid;
 687 *      offload_info4   coa_offload_info;
 688 * };
 689 */
 690static void encode_offload_info4(struct xdr_stream *xdr,
 691                                 __be32 nfserr,
 692                                 const struct nfsd4_copy *cp)
 693{
 694        __be32 *p;
 695
 696        p = xdr_reserve_space(xdr, 4);
 697        *p++ = nfserr;
 698        if (!nfserr) {
 699                p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
 700                p = xdr_encode_empty_array(p);
 701                p = xdr_encode_hyper(p, cp->cp_res.wr_bytes_written);
 702                *p++ = cpu_to_be32(cp->cp_res.wr_stable_how);
 703                p = xdr_encode_opaque_fixed(p, cp->cp_res.wr_verifier.data,
 704                                            NFS4_VERIFIER_SIZE);
 705        } else {
 706                p = xdr_reserve_space(xdr, 8);
 707                /* We always return success if bytes were written */
 708                p = xdr_encode_hyper(p, 0);
 709        }
 710}
 711
 712static void encode_cb_offload4args(struct xdr_stream *xdr,
 713                                   __be32 nfserr,
 714                                   const struct knfsd_fh *fh,
 715                                   const struct nfsd4_copy *cp,
 716                                   struct nfs4_cb_compound_hdr *hdr)
 717{
 718        __be32 *p;
 719
 720        p = xdr_reserve_space(xdr, 4);
 721        *p++ = cpu_to_be32(OP_CB_OFFLOAD);
 722        encode_nfs_fh4(xdr, fh);
 723        encode_stateid4(xdr, &cp->cp_res.cb_stateid);
 724        encode_offload_info4(xdr, nfserr, cp);
 725
 726        hdr->nops++;
 727}
 728
 729static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 730                                    struct xdr_stream *xdr,
 731                                    const void *data)
 732{
 733        const struct nfsd4_callback *cb = data;
 734        const struct nfsd4_copy *cp =
 735                container_of(cb, struct nfsd4_copy, cp_cb);
 736        struct nfs4_cb_compound_hdr hdr = {
 737                .ident = 0,
 738                .minorversion = cb->cb_clp->cl_minorversion,
 739        };
 740
 741        encode_cb_compound4args(xdr, &hdr);
 742        encode_cb_sequence4args(xdr, cb, &hdr);
 743        encode_cb_offload4args(xdr, cp->nfserr, &cp->fh, cp, &hdr);
 744        encode_cb_nops(&hdr);
 745}
 746
 747static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 748                                   struct xdr_stream *xdr,
 749                                   void *data)
 750{
 751        struct nfsd4_callback *cb = data;
 752        struct nfs4_cb_compound_hdr hdr;
 753        int status;
 754
 755        status = decode_cb_compound4res(xdr, &hdr);
 756        if (unlikely(status))
 757                return status;
 758
 759        status = decode_cb_sequence4res(xdr, cb);
 760        if (unlikely(status || cb->cb_seq_status))
 761                return status;
 762
 763        return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 764}
 765/*
 766 * RPC procedure tables
 767 */
 768#define PROC(proc, call, argtype, restype)                              \
 769[NFSPROC4_CLNT_##proc] = {                                              \
 770        .p_proc    = NFSPROC4_CB_##call,                                \
 771        .p_encode  = nfs4_xdr_enc_##argtype,            \
 772        .p_decode  = nfs4_xdr_dec_##restype,                            \
 773        .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 774        .p_replen  = NFS4_dec_##restype##_sz,                           \
 775        .p_statidx = NFSPROC4_CB_##call,                                \
 776        .p_name    = #proc,                                             \
 777}
 778
 779static const struct rpc_procinfo nfs4_cb_procedures[] = {
 780        PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 781        PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 782#ifdef CONFIG_NFSD_PNFS
 783        PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 784#endif
 785        PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 786        PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 787};
 788
 789static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 790static const struct rpc_version nfs_cb_version4 = {
 791/*
 792 * Note on the callback rpc program version number: despite language in rfc
 793 * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 794 * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 795 * in practice that appears to be what implementations use.  The section
 796 * 18.36.3 language is expected to be fixed in an erratum.
 797 */
 798        .number                 = 1,
 799        .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 800        .procs                  = nfs4_cb_procedures,
 801        .counts                 = nfs4_cb_counts,
 802};
 803
 804static const struct rpc_version *nfs_cb_version[2] = {
 805        [1] = &nfs_cb_version4,
 806};
 807
 808static const struct rpc_program cb_program;
 809
 810static struct rpc_stat cb_stats = {
 811        .program                = &cb_program
 812};
 813
 814#define NFS4_CALLBACK 0x40000000
 815static const struct rpc_program cb_program = {
 816        .name                   = "nfs4_cb",
 817        .number                 = NFS4_CALLBACK,
 818        .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 819        .version                = nfs_cb_version,
 820        .stats                  = &cb_stats,
 821        .pipe_dir_name          = "nfsd4_cb",
 822};
 823
 824static int max_cb_time(struct net *net)
 825{
 826        struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 827
 828        /*
 829         * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
 830         * so we can use 32-bit math on it. Warn if that assumption
 831         * ever stops being true.
 832         */
 833        if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
 834                return 360 * HZ;
 835
 836        return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
 837}
 838
 839static struct workqueue_struct *callback_wq;
 840
 841static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
 842{
 843        return queue_work(callback_wq, &cb->cb_work);
 844}
 845
 846static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
 847{
 848        atomic_inc(&clp->cl_cb_inflight);
 849}
 850
 851static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
 852{
 853
 854        if (atomic_dec_and_test(&clp->cl_cb_inflight))
 855                wake_up_var(&clp->cl_cb_inflight);
 856}
 857
 858static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
 859{
 860        wait_var_event(&clp->cl_cb_inflight,
 861                        !atomic_read(&clp->cl_cb_inflight));
 862}
 863
 864static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 865{
 866        if (clp->cl_minorversion == 0) {
 867                client->cl_principal = clp->cl_cred.cr_targ_princ ?
 868                        clp->cl_cred.cr_targ_princ : "nfs";
 869
 870                return get_cred(rpc_machine_cred());
 871        } else {
 872                struct cred *kcred;
 873
 874                kcred = prepare_kernel_cred(NULL);
 875                if (!kcred)
 876                        return NULL;
 877
 878                kcred->uid = ses->se_cb_sec.uid;
 879                kcred->gid = ses->se_cb_sec.gid;
 880                return kcred;
 881        }
 882}
 883
 884static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 885{
 886        int maxtime = max_cb_time(clp->net);
 887        struct rpc_timeout      timeparms = {
 888                .to_initval     = maxtime,
 889                .to_retries     = 0,
 890                .to_maxval      = maxtime,
 891        };
 892        struct rpc_create_args args = {
 893                .net            = clp->net,
 894                .address        = (struct sockaddr *) &conn->cb_addr,
 895                .addrsize       = conn->cb_addrlen,
 896                .saddress       = (struct sockaddr *) &conn->cb_saddr,
 897                .timeout        = &timeparms,
 898                .program        = &cb_program,
 899                .version        = 1,
 900                .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 901                .cred           = current_cred(),
 902        };
 903        struct rpc_clnt *client;
 904        const struct cred *cred;
 905
 906        if (clp->cl_minorversion == 0) {
 907                if (!clp->cl_cred.cr_principal &&
 908                    (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
 909                        trace_nfsd_cb_setup_err(clp, -EINVAL);
 910                        return -EINVAL;
 911                }
 912                args.client_name = clp->cl_cred.cr_principal;
 913                args.prognumber = conn->cb_prog;
 914                args.protocol = XPRT_TRANSPORT_TCP;
 915                args.authflavor = clp->cl_cred.cr_flavor;
 916                clp->cl_cb_ident = conn->cb_ident;
 917        } else {
 918                if (!conn->cb_xprt)
 919                        return -EINVAL;
 920                clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 921                clp->cl_cb_session = ses;
 922                args.bc_xprt = conn->cb_xprt;
 923                args.prognumber = clp->cl_cb_session->se_cb_prog;
 924                args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 925                                XPRT_TRANSPORT_BC;
 926                args.authflavor = ses->se_cb_sec.flavor;
 927        }
 928        /* Create RPC client */
 929        client = rpc_create(&args);
 930        if (IS_ERR(client)) {
 931                trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
 932                return PTR_ERR(client);
 933        }
 934        cred = get_backchannel_cred(clp, client, ses);
 935        if (!cred) {
 936                trace_nfsd_cb_setup_err(clp, -ENOMEM);
 937                rpc_shutdown_client(client);
 938                return -ENOMEM;
 939        }
 940        clp->cl_cb_client = client;
 941        clp->cl_cb_cred = cred;
 942        rcu_read_lock();
 943        trace_nfsd_cb_setup(clp, rpc_peeraddr2str(client, RPC_DISPLAY_NETID),
 944                            args.authflavor);
 945        rcu_read_unlock();
 946        return 0;
 947}
 948
 949static void nfsd4_mark_cb_state(struct nfs4_client *clp, int newstate)
 950{
 951        if (clp->cl_cb_state != newstate) {
 952                clp->cl_cb_state = newstate;
 953                trace_nfsd_cb_state(clp);
 954        }
 955}
 956
 957static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 958{
 959        if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 960                return;
 961        nfsd4_mark_cb_state(clp, NFSD4_CB_DOWN);
 962}
 963
 964static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 965{
 966        if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 967                return;
 968        nfsd4_mark_cb_state(clp, NFSD4_CB_FAULT);
 969}
 970
 971static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 972{
 973        struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 974
 975        if (task->tk_status)
 976                nfsd4_mark_cb_down(clp, task->tk_status);
 977        else
 978                nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
 979}
 980
 981static void nfsd4_cb_probe_release(void *calldata)
 982{
 983        struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 984
 985        nfsd41_cb_inflight_end(clp);
 986
 987}
 988
 989static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 990        /* XXX: release method to ensure we set the cb channel down if
 991         * necessary on early failure? */
 992        .rpc_call_done = nfsd4_cb_probe_done,
 993        .rpc_release = nfsd4_cb_probe_release,
 994};
 995
 996/*
 997 * Poke the callback thread to process any updates to the callback
 998 * parameters, and send a null probe.
 999 */
1000void nfsd4_probe_callback(struct nfs4_client *clp)
1001{
1002        trace_nfsd_cb_probe(clp);
1003        nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1004        set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1005        nfsd4_run_cb(&clp->cl_cb_null);
1006}
1007
1008void nfsd4_probe_callback_sync(struct nfs4_client *clp)
1009{
1010        nfsd4_probe_callback(clp);
1011        flush_workqueue(callback_wq);
1012}
1013
1014void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
1015{
1016        nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1017        spin_lock(&clp->cl_lock);
1018        memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
1019        spin_unlock(&clp->cl_lock);
1020}
1021
1022/*
1023 * There's currently a single callback channel slot.
1024 * If the slot is available, then mark it busy.  Otherwise, set the
1025 * thread for sleeping on the callback RPC wait queue.
1026 */
1027static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
1028{
1029        struct nfs4_client *clp = cb->cb_clp;
1030
1031        if (!cb->cb_holds_slot &&
1032            test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1033                rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1034                /* Race breaker */
1035                if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1036                        dprintk("%s slot is busy\n", __func__);
1037                        return false;
1038                }
1039                rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1040        }
1041        cb->cb_holds_slot = true;
1042        return true;
1043}
1044
1045static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
1046{
1047        struct nfs4_client *clp = cb->cb_clp;
1048
1049        if (cb->cb_holds_slot) {
1050                cb->cb_holds_slot = false;
1051                clear_bit(0, &clp->cl_cb_slot_busy);
1052                rpc_wake_up_next(&clp->cl_cb_waitq);
1053        }
1054}
1055
1056static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
1057{
1058        struct nfs4_client *clp = cb->cb_clp;
1059
1060        nfsd41_cb_release_slot(cb);
1061        if (cb->cb_ops && cb->cb_ops->release)
1062                cb->cb_ops->release(cb);
1063        nfsd41_cb_inflight_end(clp);
1064}
1065
1066/*
1067 * TODO: cb_sequence should support referring call lists, cachethis, multiple
1068 * slots, and mark callback channel down on communication errors.
1069 */
1070static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1071{
1072        struct nfsd4_callback *cb = calldata;
1073        struct nfs4_client *clp = cb->cb_clp;
1074        u32 minorversion = clp->cl_minorversion;
1075
1076        /*
1077         * cb_seq_status is only set in decode_cb_sequence4res,
1078         * and so will remain 1 if an rpc level failure occurs.
1079         */
1080        cb->cb_seq_status = 1;
1081        cb->cb_status = 0;
1082        if (minorversion && !nfsd41_cb_get_slot(cb, task))
1083                return;
1084        rpc_call_start(task);
1085}
1086
1087static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1088{
1089        struct nfs4_client *clp = cb->cb_clp;
1090        struct nfsd4_session *session = clp->cl_cb_session;
1091        bool ret = true;
1092
1093        if (!clp->cl_minorversion) {
1094                /*
1095                 * If the backchannel connection was shut down while this
1096                 * task was queued, we need to resubmit it after setting up
1097                 * a new backchannel connection.
1098                 *
1099                 * Note that if we lost our callback connection permanently
1100                 * the submission code will error out, so we don't need to
1101                 * handle that case here.
1102                 */
1103                if (RPC_SIGNALLED(task))
1104                        goto need_restart;
1105
1106                return true;
1107        }
1108
1109        if (!cb->cb_holds_slot)
1110                goto need_restart;
1111
1112        switch (cb->cb_seq_status) {
1113        case 0:
1114                /*
1115                 * No need for lock, access serialized in nfsd4_cb_prepare
1116                 *
1117                 * RFC5661 20.9.3
1118                 * If CB_SEQUENCE returns an error, then the state of the slot
1119                 * (sequence ID, cached reply) MUST NOT change.
1120                 */
1121                ++session->se_cb_seq_nr;
1122                break;
1123        case -ESERVERFAULT:
1124                ++session->se_cb_seq_nr;
1125                fallthrough;
1126        case 1:
1127        case -NFS4ERR_BADSESSION:
1128                nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1129                ret = false;
1130                break;
1131        case -NFS4ERR_DELAY:
1132                if (!rpc_restart_call(task))
1133                        goto out;
1134
1135                rpc_delay(task, 2 * HZ);
1136                return false;
1137        case -NFS4ERR_BADSLOT:
1138                goto retry_nowait;
1139        case -NFS4ERR_SEQ_MISORDERED:
1140                if (session->se_cb_seq_nr != 1) {
1141                        session->se_cb_seq_nr = 1;
1142                        goto retry_nowait;
1143                }
1144                break;
1145        default:
1146                nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1147                dprintk("%s: unprocessed error %d\n", __func__,
1148                        cb->cb_seq_status);
1149        }
1150
1151        nfsd41_cb_release_slot(cb);
1152        dprintk("%s: freed slot, new seqid=%d\n", __func__,
1153                clp->cl_cb_session->se_cb_seq_nr);
1154
1155        if (RPC_SIGNALLED(task))
1156                goto need_restart;
1157out:
1158        return ret;
1159retry_nowait:
1160        if (rpc_restart_call_prepare(task))
1161                ret = false;
1162        goto out;
1163need_restart:
1164        if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
1165                task->tk_status = 0;
1166                cb->cb_need_restart = true;
1167        }
1168        return false;
1169}
1170
1171static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1172{
1173        struct nfsd4_callback *cb = calldata;
1174        struct nfs4_client *clp = cb->cb_clp;
1175
1176        if (!nfsd4_cb_sequence_done(task, cb))
1177                return;
1178
1179        if (cb->cb_status) {
1180                WARN_ON_ONCE(task->tk_status);
1181                task->tk_status = cb->cb_status;
1182        }
1183
1184        switch (cb->cb_ops->done(cb, task)) {
1185        case 0:
1186                task->tk_status = 0;
1187                rpc_restart_call_prepare(task);
1188                return;
1189        case 1:
1190                switch (task->tk_status) {
1191                case -EIO:
1192                case -ETIMEDOUT:
1193                case -EACCES:
1194                        nfsd4_mark_cb_down(clp, task->tk_status);
1195                }
1196                break;
1197        default:
1198                BUG();
1199        }
1200}
1201
1202static void nfsd4_cb_release(void *calldata)
1203{
1204        struct nfsd4_callback *cb = calldata;
1205
1206        if (cb->cb_need_restart)
1207                nfsd4_queue_cb(cb);
1208        else
1209                nfsd41_destroy_cb(cb);
1210
1211}
1212
1213static const struct rpc_call_ops nfsd4_cb_ops = {
1214        .rpc_call_prepare = nfsd4_cb_prepare,
1215        .rpc_call_done = nfsd4_cb_done,
1216        .rpc_release = nfsd4_cb_release,
1217};
1218
1219int nfsd4_create_callback_queue(void)
1220{
1221        callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1222        if (!callback_wq)
1223                return -ENOMEM;
1224        return 0;
1225}
1226
1227void nfsd4_destroy_callback_queue(void)
1228{
1229        destroy_workqueue(callback_wq);
1230}
1231
1232/* must be called under the state lock */
1233void nfsd4_shutdown_callback(struct nfs4_client *clp)
1234{
1235        if (clp->cl_cb_state != NFSD4_CB_UNKNOWN)
1236                trace_nfsd_cb_shutdown(clp);
1237
1238        set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1239        /*
1240         * Note this won't actually result in a null callback;
1241         * instead, nfsd4_run_cb_null() will detect the killed
1242         * client, destroy the rpc client, and stop:
1243         */
1244        nfsd4_run_cb(&clp->cl_cb_null);
1245        flush_workqueue(callback_wq);
1246        nfsd41_cb_inflight_wait_complete(clp);
1247}
1248
1249/* requires cl_lock: */
1250static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1251{
1252        struct nfsd4_session *s;
1253        struct nfsd4_conn *c;
1254
1255        list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1256                list_for_each_entry(c, &s->se_conns, cn_persession) {
1257                        if (c->cn_flags & NFS4_CDFC4_BACK)
1258                                return c;
1259                }
1260        }
1261        return NULL;
1262}
1263
1264/*
1265 * Note there isn't a lot of locking in this code; instead we depend on
1266 * the fact that it is run from the callback_wq, which won't run two
1267 * work items at once.  So, for example, callback_wq handles all access
1268 * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
1269 */
1270static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1271{
1272        struct nfs4_cb_conn conn;
1273        struct nfs4_client *clp = cb->cb_clp;
1274        struct nfsd4_session *ses = NULL;
1275        struct nfsd4_conn *c;
1276        int err;
1277
1278        /*
1279         * This is either an update, or the client dying; in either case,
1280         * kill the old client:
1281         */
1282        if (clp->cl_cb_client) {
1283                rpc_shutdown_client(clp->cl_cb_client);
1284                clp->cl_cb_client = NULL;
1285                put_cred(clp->cl_cb_cred);
1286                clp->cl_cb_cred = NULL;
1287        }
1288        if (clp->cl_cb_conn.cb_xprt) {
1289                svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1290                clp->cl_cb_conn.cb_xprt = NULL;
1291        }
1292        if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1293                return;
1294        spin_lock(&clp->cl_lock);
1295        /*
1296         * Only serialized callback code is allowed to clear these
1297         * flags; main nfsd code can only set them:
1298         */
1299        BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1300        clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1301        memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1302        c = __nfsd4_find_backchannel(clp);
1303        if (c) {
1304                svc_xprt_get(c->cn_xprt);
1305                conn.cb_xprt = c->cn_xprt;
1306                ses = c->cn_session;
1307        }
1308        spin_unlock(&clp->cl_lock);
1309
1310        err = setup_callback_client(clp, &conn, ses);
1311        if (err) {
1312                nfsd4_mark_cb_down(clp, err);
1313                if (c)
1314                        svc_xprt_put(c->cn_xprt);
1315                return;
1316        }
1317}
1318
1319static void
1320nfsd4_run_cb_work(struct work_struct *work)
1321{
1322        struct nfsd4_callback *cb =
1323                container_of(work, struct nfsd4_callback, cb_work);
1324        struct nfs4_client *clp = cb->cb_clp;
1325        struct rpc_clnt *clnt;
1326        int flags;
1327
1328        if (cb->cb_need_restart) {
1329                cb->cb_need_restart = false;
1330        } else {
1331                if (cb->cb_ops && cb->cb_ops->prepare)
1332                        cb->cb_ops->prepare(cb);
1333        }
1334
1335        if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1336                nfsd4_process_cb_update(cb);
1337
1338        clnt = clp->cl_cb_client;
1339        if (!clnt) {
1340                /* Callback channel broken, or client killed; give up: */
1341                nfsd41_destroy_cb(cb);
1342                return;
1343        }
1344
1345        /*
1346         * Don't send probe messages for 4.1 or later.
1347         */
1348        if (!cb->cb_ops && clp->cl_minorversion) {
1349                nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1350                nfsd41_destroy_cb(cb);
1351                return;
1352        }
1353
1354        cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1355        flags = clp->cl_minorversion ? RPC_TASK_NOCONNECT : RPC_TASK_SOFTCONN;
1356        rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | flags,
1357                        cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1358}
1359
1360void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1361                const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1362{
1363        cb->cb_clp = clp;
1364        cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1365        cb->cb_msg.rpc_argp = cb;
1366        cb->cb_msg.rpc_resp = cb;
1367        cb->cb_ops = ops;
1368        INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1369        cb->cb_seq_status = 1;
1370        cb->cb_status = 0;
1371        cb->cb_need_restart = false;
1372        cb->cb_holds_slot = false;
1373}
1374
1375void nfsd4_run_cb(struct nfsd4_callback *cb)
1376{
1377        struct nfs4_client *clp = cb->cb_clp;
1378
1379        nfsd41_cb_inflight_begin(clp);
1380        if (!nfsd4_queue_cb(cb))
1381                nfsd41_cb_inflight_end(clp);
1382}
1383
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