fs/nfsd/nfs4callback.c

   1 /*
   2  *  Copyright (c) 2001 The Regents of the University of Michigan.
   3  *  All rights reserved.
   4  *
   5  *  Kendrick Smith <kmsmith@umich.edu>
   6  *  Andy Adamson <andros@umich.edu>
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions
  10  *  are met:
  11  *
  12  *  1. Redistributions of source code must retain the above copyright
  13  *     notice, this list of conditions and the following disclaimer.
  14  *  2. Redistributions in binary form must reproduce the above copyright
  15  *     notice, this list of conditions and the following disclaimer in the
  16  *     documentation and/or other materials provided with the distribution.
  17  *  3. Neither the name of the University nor the names of its
  18  *     contributors may be used to endorse or promote products derived
  19  *     from this software without specific prior written permission.
  20  *
  21  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  22  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  29  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  31  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/xprt.h>
  36 #include <linux/sunrpc/svc_xprt.h>
  37 #include <linux/slab.h>
  38 #include "nfsd.h"
  39 #include "state.h"
  40 #include "netns.h"
  41 #include "xdr4cb.h"
  42 #include "xdr4.h"
  43
  44 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  45
  46 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  47
  48 #define NFSPROC4_CB_NULL 0
  49 #define NFSPROC4_CB_COMPOUND 1
  50
  51 /* Index of predefined Linux callback client operations */
  52
  53 struct nfs4_cb_compound_hdr {
  54         /* args */
  55         u32             ident;  /* minorversion 0 only */
  56         u32             nops;
  57         __be32          *nops_p;
  58         u32             minorversion;
  59         /* res */
  60         int             status;
  61 };
  62
  63 /*
  64  * Handle decode buffer overflows out-of-line.
  65  */
  66 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  67 {
  68         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  69                 "Remaining buffer length is %tu words.\n",
  70                 func, xdr->end - xdr->p);
  71 }
  72
  73 static __be32 *xdr_encode_empty_array(__be32 *p)
  74 {
  75         *p++ = xdr_zero;
  76         return p;
  77 }
  78
  79 /*
  80  * Encode/decode NFSv4 CB basic data types
  81  *
  82  * Basic NFSv4 callback data types are defined in section 15 of RFC
  83  * 3530: "Network File System (NFS) version 4 Protocol" and section
  84  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
  85  * 1 Protocol"
  86  */
  87
  88 /*
  89  *      nfs_cb_opnum4
  90  *
  91  *      enum nfs_cb_opnum4 {
  92  *              OP_CB_GETATTR           = 3,
  93  *                ...
  94  *      };
  95  */
  96 enum nfs_cb_opnum4 {
  97         OP_CB_GETATTR                   = 3,
  98         OP_CB_RECALL                    = 4,
  99         OP_CB_LAYOUTRECALL              = 5,
 100         OP_CB_NOTIFY                    = 6,
 101         OP_CB_PUSH_DELEG                = 7,
 102         OP_CB_RECALL_ANY                = 8,
 103         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 104         OP_CB_RECALL_SLOT               = 10,
 105         OP_CB_SEQUENCE                  = 11,
 106         OP_CB_WANTS_CANCELLED           = 12,
 107         OP_CB_NOTIFY_LOCK               = 13,
 108         OP_CB_NOTIFY_DEVICEID           = 14,
 109         OP_CB_OFFLOAD                   = 15,
 110         OP_CB_ILLEGAL                   = 10044
 111 };
 112
 113 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 114 {
 115         __be32 *p;
 116
 117         p = xdr_reserve_space(xdr, 4);
 118         *p = cpu_to_be32(op);
 119 }
 120
 121 /*
 122  * nfs_fh4
 123  *
 124  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 125  */
 126 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 127 {
 128         u32 length = fh->fh_size;
 129         __be32 *p;
 130
 131         BUG_ON(length > NFS4_FHSIZE);
 132         p = xdr_reserve_space(xdr, 4 + length);
 133         xdr_encode_opaque(p, &fh->fh_base, length);
 134 }
 135
 136 /*
 137  * stateid4
 138  *
 139  *      struct stateid4 {
 140  *              uint32_t        seqid;
 141  *              opaque          other[12];
 142  *      };
 143  */
 144 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 145 {
 146         __be32 *p;
 147
 148         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 149         *p++ = cpu_to_be32(sid->si_generation);
 150         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 151 }
 152
 153 /*
 154  * sessionid4
 155  *
 156  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 157  */
 158 static void encode_sessionid4(struct xdr_stream *xdr,
 159                               const struct nfsd4_session *session)
 160 {
 161         __be32 *p;
 162
 163         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 164         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 165                                         NFS4_MAX_SESSIONID_LEN);
 166 }
 167
 168 /*
 169  * nfsstat4
 170  */
 171 static const struct {
 172         int stat;
 173         int errno;
 174 } nfs_cb_errtbl[] = {
 175         { NFS4_OK,              0               },
 176         { NFS4ERR_PERM,         -EPERM          },
 177         { NFS4ERR_NOENT,        -ENOENT         },
 178         { NFS4ERR_IO,           -EIO            },
 179         { NFS4ERR_NXIO,         -ENXIO          },
 180         { NFS4ERR_ACCESS,       -EACCES         },
 181         { NFS4ERR_EXIST,        -EEXIST         },
 182         { NFS4ERR_XDEV,         -EXDEV          },
 183         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 184         { NFS4ERR_ISDIR,        -EISDIR         },
 185         { NFS4ERR_INVAL,        -EINVAL         },
 186         { NFS4ERR_FBIG,         -EFBIG          },
 187         { NFS4ERR_NOSPC,        -ENOSPC         },
 188         { NFS4ERR_ROFS,         -EROFS          },
 189         { NFS4ERR_MLINK,        -EMLINK         },
 190         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 191         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 192         { NFS4ERR_DQUOT,        -EDQUOT         },
 193         { NFS4ERR_STALE,        -ESTALE         },
 194         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 195         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 196         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 197         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 198         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 199         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 200         { NFS4ERR_LOCKED,       -EAGAIN         },
 201         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 202         { NFS4ERR_SYMLINK,      -ELOOP          },
 203         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 204         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 205         { -1,                   -EIO            }
 206 };
 207
 208 /*
 209  * If we cannot translate the error, the recovery routines should
 210  * handle it.
 211  *
 212  * Note: remaining NFSv4 error codes have values > 10000, so should
 213  * not conflict with native Linux error codes.
 214  */
 215 static int nfs_cb_stat_to_errno(int status)
 216 {
 217         int i;
 218
 219         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 220                 if (nfs_cb_errtbl[i].stat == status)
 221                         return nfs_cb_errtbl[i].errno;
 222         }
 223
 224         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 225         return -status;
 226 }
 227
 228 static int decode_cb_op_status(struct xdr_stream *xdr,
 229                                enum nfs_cb_opnum4 expected, int *status)
 230 {
 231         __be32 *p;
 232         u32 op;
 233
 234         p = xdr_inline_decode(xdr, 4 + 4);
 235         if (unlikely(p == NULL))
 236                 goto out_overflow;
 237         op = be32_to_cpup(p++);
 238         if (unlikely(op != expected))
 239                 goto out_unexpected;
 240         *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 241         return 0;
 242 out_overflow:
 243         print_overflow_msg(__func__, xdr);
 244         return -EIO;
 245 out_unexpected:
 246         dprintk("NFSD: Callback server returned operation %d but "
 247                 "we issued a request for %d\n", op, expected);
 248         return -EIO;
 249 }
 250
 251 /*
 252  * CB_COMPOUND4args
 253  *
 254  *      struct CB_COMPOUND4args {
 255  *              utf8str_cs      tag;
 256  *              uint32_t        minorversion;
 257  *              uint32_t        callback_ident;
 258  *              nfs_cb_argop4   argarray<>;
 259  *      };
 260 */
 261 static void encode_cb_compound4args(struct xdr_stream *xdr,
 262                                     struct nfs4_cb_compound_hdr *hdr)
 263 {
 264         __be32 * p;
 265
 266         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 267         p = xdr_encode_empty_array(p);          /* empty tag */
 268         *p++ = cpu_to_be32(hdr->minorversion);
 269         *p++ = cpu_to_be32(hdr->ident);
 270
 271         hdr->nops_p = p;
 272         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 273 }
 274
 275 /*
 276  * Update argarray element count
 277  */
 278 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 279 {
 280         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 281         *hdr->nops_p = cpu_to_be32(hdr->nops);
 282 }
 283
 284 /*
 285  * CB_COMPOUND4res
 286  *
 287  *      struct CB_COMPOUND4res {
 288  *              nfsstat4        status;
 289  *              utf8str_cs      tag;
 290  *              nfs_cb_resop4   resarray<>;
 291  *      };
 292  */
 293 static int decode_cb_compound4res(struct xdr_stream *xdr,
 294                                   struct nfs4_cb_compound_hdr *hdr)
 295 {
 296         u32 length;
 297         __be32 *p;
 298
 299         p = xdr_inline_decode(xdr, 4 + 4);
 300         if (unlikely(p == NULL))
 301                 goto out_overflow;
 302         hdr->status = be32_to_cpup(p++);
 303         /* Ignore the tag */
 304         length = be32_to_cpup(p++);
 305         p = xdr_inline_decode(xdr, length + 4);
 306         if (unlikely(p == NULL))
 307                 goto out_overflow;
 308         p += XDR_QUADLEN(length);
 309         hdr->nops = be32_to_cpup(p);
 310         return 0;
 311 out_overflow:
 312         print_overflow_msg(__func__, xdr);
 313         return -EIO;
 314 }
 315
 316 /*
 317  * CB_RECALL4args
 318  *
 319  *      struct CB_RECALL4args {
 320  *              stateid4        stateid;
 321  *              bool            truncate;
 322  *              nfs_fh4         fh;
 323  *      };
 324  */
 325 static void encode_cb_recall4args(struct xdr_stream *xdr,
 326                                   const struct nfs4_delegation *dp,
 327                                   struct nfs4_cb_compound_hdr *hdr)
 328 {
 329         __be32 *p;
 330
 331         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 332         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 333
 334         p = xdr_reserve_space(xdr, 4);
 335         *p++ = xdr_zero;                        /* truncate */
 336
 337         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 338
 339         hdr->nops++;
 340 }
 341
 342 /*
 343  * CB_SEQUENCE4args
 344  *
 345  *      struct CB_SEQUENCE4args {
 346  *              sessionid4              csa_sessionid;
 347  *              sequenceid4             csa_sequenceid;
 348  *              slotid4                 csa_slotid;
 349  *              slotid4                 csa_highest_slotid;
 350  *              bool                    csa_cachethis;
 351  *              referring_call_list4    csa_referring_call_lists<>;
 352  *      };
 353  */
 354 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 355                                     const struct nfsd4_callback *cb,
 356                                     struct nfs4_cb_compound_hdr *hdr)
 357 {
 358         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 359         __be32 *p;
 360
 361         if (hdr->minorversion == 0)
 362                 return;
 363
 364         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 365         encode_sessionid4(xdr, session);
 366
 367         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 368         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 369         *p++ = xdr_zero;                        /* csa_slotid */
 370         *p++ = xdr_zero;                        /* csa_highest_slotid */
 371         *p++ = xdr_zero;                        /* csa_cachethis */
 372         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 373
 374         hdr->nops++;
 375 }
 376
 377 /*
 378  * CB_SEQUENCE4resok
 379  *
 380  *      struct CB_SEQUENCE4resok {
 381  *              sessionid4      csr_sessionid;
 382  *              sequenceid4     csr_sequenceid;
 383  *              slotid4         csr_slotid;
 384  *              slotid4         csr_highest_slotid;
 385  *              slotid4         csr_target_highest_slotid;
 386  *      };
 387  *
 388  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 389  *      case NFS4_OK:
 390  *              CB_SEQUENCE4resok       csr_resok4;
 391  *      default:
 392  *              void;
 393  *      };
 394  *
 395  * Our current back channel implmentation supports a single backchannel
 396  * with a single slot.
 397  */
 398 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 399                                     struct nfsd4_callback *cb)
 400 {
 401         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 402         int status = -ESERVERFAULT;
 403         __be32 *p;
 404         u32 dummy;
 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
 414         if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 415                 dprintk("NFS: %s Invalid session id\n", __func__);
 416                 goto out;
 417         }
 418         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 419
 420         dummy = be32_to_cpup(p++);
 421         if (dummy != session->se_cb_seq_nr) {
 422                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 423                 goto out;
 424         }
 425
 426         dummy = be32_to_cpup(p++);
 427         if (dummy != 0) {
 428                 dprintk("NFS: %s Invalid slotid\n", __func__);
 429                 goto out;
 430         }
 431
 432         /*
 433          * FIXME: process highest slotid and target highest slotid
 434          */
 435         status = 0;
 436 out:
 437         cb->cb_seq_status = status;
 438         return status;
 439 out_overflow:
 440         print_overflow_msg(__func__, xdr);
 441         status = -EIO;
 442         goto out;
 443 }
 444
 445 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 446                                   struct nfsd4_callback *cb)
 447 {
 448         int status;
 449
 450         if (cb->cb_clp->cl_minorversion == 0)
 451                 return 0;
 452
 453         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 454         if (unlikely(status || cb->cb_seq_status))
 455                 return status;
 456
 457         return decode_cb_sequence4resok(xdr, cb);
 458 }
 459
 460 /*
 461  * NFSv4.0 and NFSv4.1 XDR encode functions
 462  *
 463  * NFSv4.0 callback argument types are defined in section 15 of RFC
 464  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 465  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 466  * Protocol".
 467  */
 468
 469 /*
 470  * NB: Without this zero space reservation, callbacks over krb5p fail
 471  */
 472 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 473                                  const void *__unused)
 474 {
 475         xdr_reserve_space(xdr, 0);
 476 }
 477
 478 /*
 479  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 480  */
 481 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 482                                    const void *data)
 483 {
 484         const struct nfsd4_callback *cb = data;
 485         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 486         struct nfs4_cb_compound_hdr hdr = {
 487                 .ident = cb->cb_clp->cl_cb_ident,
 488                 .minorversion = cb->cb_clp->cl_minorversion,
 489         };
 490
 491         encode_cb_compound4args(xdr, &hdr);
 492         encode_cb_sequence4args(xdr, cb, &hdr);
 493         encode_cb_recall4args(xdr, dp, &hdr);
 494         encode_cb_nops(&hdr);
 495 }
 496
 497
 498 /*
 499  * NFSv4.0 and NFSv4.1 XDR decode functions
 500  *
 501  * NFSv4.0 callback result types are defined in section 15 of RFC
 502  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 503  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 504  * Protocol".
 505  */
 506
 507 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 508                                 void *__unused)
 509 {
 510         return 0;
 511 }
 512
 513 /*
 514  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 515  */
 516 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 517                                   struct xdr_stream *xdr,
 518                                   void *data)
 519 {
 520         struct nfsd4_callback *cb = data;
 521         struct nfs4_cb_compound_hdr hdr;
 522         int status;
 523
 524         status = decode_cb_compound4res(xdr, &hdr);
 525         if (unlikely(status))
 526                 return status;
 527
 528         if (cb != NULL) {
 529                 status = decode_cb_sequence4res(xdr, cb);
 530                 if (unlikely(status || cb->cb_seq_status))
 531                         return status;
 532         }
 533
 534         return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 535 }
 536
 537 #ifdef CONFIG_NFSD_PNFS
 538 /*
 539  * CB_LAYOUTRECALL4args
 540  *
 541  *      struct layoutrecall_file4 {
 542  *              nfs_fh4         lor_fh;
 543  *              offset4         lor_offset;
 544  *              length4         lor_length;
 545  *              stateid4        lor_stateid;
 546  *      };
 547  *
 548  *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 549  *      case LAYOUTRECALL4_FILE:
 550  *              layoutrecall_file4 lor_layout;
 551  *      case LAYOUTRECALL4_FSID:
 552  *              fsid4              lor_fsid;
 553  *      case LAYOUTRECALL4_ALL:
 554  *              void;
 555  *      };
 556  *
 557  *      struct CB_LAYOUTRECALL4args {
 558  *              layouttype4             clora_type;
 559  *              layoutiomode4           clora_iomode;
 560  *              bool                    clora_changed;
 561  *              layoutrecall4           clora_recall;
 562  *      };
 563  */
 564 static void encode_cb_layout4args(struct xdr_stream *xdr,
 565                                   const struct nfs4_layout_stateid *ls,
 566                                   struct nfs4_cb_compound_hdr *hdr)
 567 {
 568         __be32 *p;
 569
 570         BUG_ON(hdr->minorversion == 0);
 571
 572         p = xdr_reserve_space(xdr, 5 * 4);
 573         *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 574         *p++ = cpu_to_be32(ls->ls_layout_type);
 575         *p++ = cpu_to_be32(IOMODE_ANY);
 576         *p++ = cpu_to_be32(1);
 577         *p = cpu_to_be32(RETURN_FILE);
 578
 579         encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 580
 581         p = xdr_reserve_space(xdr, 2 * 8);
 582         p = xdr_encode_hyper(p, 0);
 583         xdr_encode_hyper(p, NFS4_MAX_UINT64);
 584
 585         encode_stateid4(xdr, &ls->ls_recall_sid);
 586
 587         hdr->nops++;
 588 }
 589
 590 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 591                                    struct xdr_stream *xdr,
 592                                    const void *data)
 593 {
 594         const struct nfsd4_callback *cb = data;
 595         const struct nfs4_layout_stateid *ls =
 596                 container_of(cb, struct nfs4_layout_stateid, ls_recall);
 597         struct nfs4_cb_compound_hdr hdr = {
 598                 .ident = 0,
 599                 .minorversion = cb->cb_clp->cl_minorversion,
 600         };
 601
 602         encode_cb_compound4args(xdr, &hdr);
 603         encode_cb_sequence4args(xdr, cb, &hdr);
 604         encode_cb_layout4args(xdr, ls, &hdr);
 605         encode_cb_nops(&hdr);
 606 }
 607
 608 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 609                                   struct xdr_stream *xdr,
 610                                   void *data)
 611 {
 612         struct nfsd4_callback *cb = data;
 613         struct nfs4_cb_compound_hdr hdr;
 614         int status;
 615
 616         status = decode_cb_compound4res(xdr, &hdr);
 617         if (unlikely(status))
 618                 return status;
 619
 620         if (cb) {
 621                 status = decode_cb_sequence4res(xdr, cb);
 622                 if (unlikely(status || cb->cb_seq_status))
 623                         return status;
 624         }
 625         return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 626 }
 627 #endif /* CONFIG_NFSD_PNFS */
 628
 629 static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
 630 {
 631         __be32  *p;
 632
 633         p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
 634         p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
 635         xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
 636 }
 637
 638 static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 639                                         struct xdr_stream *xdr,
 640                                         const void *data)
 641 {
 642         const struct nfsd4_callback *cb = data;
 643         const struct nfsd4_blocked_lock *nbl =
 644                 container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
 645         struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
 646         struct nfs4_cb_compound_hdr hdr = {
 647                 .ident = 0,
 648                 .minorversion = cb->cb_clp->cl_minorversion,
 649         };
 650
 651         __be32 *p;
 652
 653         BUG_ON(hdr.minorversion == 0);
 654
 655         encode_cb_compound4args(xdr, &hdr);
 656         encode_cb_sequence4args(xdr, cb, &hdr);
 657
 658         p = xdr_reserve_space(xdr, 4);
 659         *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
 660         encode_nfs_fh4(xdr, &nbl->nbl_fh);
 661         encode_stateowner(xdr, &lo->lo_owner);
 662         hdr.nops++;
 663
 664         encode_cb_nops(&hdr);
 665 }
 666
 667 static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 668                                         struct xdr_stream *xdr,
 669                                         void *data)
 670 {
 671         struct nfsd4_callback *cb = data;
 672         struct nfs4_cb_compound_hdr hdr;
 673         int status;
 674
 675         status = decode_cb_compound4res(xdr, &hdr);
 676         if (unlikely(status))
 677                 return status;
 678
 679         if (cb) {
 680                 status = decode_cb_sequence4res(xdr, cb);
 681                 if (unlikely(status || cb->cb_seq_status))
 682                         return status;
 683         }
 684         return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
 685 }
 686
 687 /*
 688  * struct write_response4 {
 689  *      stateid4        wr_callback_id<1>;
 690  *      length4         wr_count;
 691  *      stable_how4     wr_committed;
 692  *      verifier4       wr_writeverf;
 693  * };
 694  * union offload_info4 switch (nfsstat4 coa_status) {
 695  *      case NFS4_OK:
 696  *              write_response4 coa_resok4;
 697  *      default:
 698  *      length4         coa_bytes_copied;
 699  * };
 700  * struct CB_OFFLOAD4args {
 701  *      nfs_fh4         coa_fh;
 702  *      stateid4        coa_stateid;
 703  *      offload_info4   coa_offload_info;
 704  * };
 705  */
 706 static void encode_offload_info4(struct xdr_stream *xdr,
 707                                  __be32 nfserr,
 708                                  const struct nfsd4_copy *cp)
 709 {
 710         __be32 *p;
 711
 712         p = xdr_reserve_space(xdr, 4);
 713         *p++ = nfserr;
 714         if (!nfserr) {
 715                 p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
 716                 p = xdr_encode_empty_array(p);
 717                 p = xdr_encode_hyper(p, cp->cp_res.wr_bytes_written);
 718                 *p++ = cpu_to_be32(cp->cp_res.wr_stable_how);
 719                 p = xdr_encode_opaque_fixed(p, cp->cp_res.wr_verifier.data,
 720                                             NFS4_VERIFIER_SIZE);
 721         } else {
 722                 p = xdr_reserve_space(xdr, 8);
 723                 /* We always return success if bytes were written */
 724                 p = xdr_encode_hyper(p, 0);
 725         }
 726 }
 727
 728 static void encode_cb_offload4args(struct xdr_stream *xdr,
 729                                    __be32 nfserr,
 730                                    const struct knfsd_fh *fh,
 731                                    const struct nfsd4_copy *cp,
 732                                    struct nfs4_cb_compound_hdr *hdr)
 733 {
 734         __be32 *p;
 735
 736         p = xdr_reserve_space(xdr, 4);
 737         *p++ = cpu_to_be32(OP_CB_OFFLOAD);
 738         encode_nfs_fh4(xdr, fh);
 739         encode_stateid4(xdr, &cp->cp_res.cb_stateid);
 740         encode_offload_info4(xdr, nfserr, cp);
 741
 742         hdr->nops++;
 743 }
 744
 745 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 746                                     struct xdr_stream *xdr,
 747                                     const void *data)
 748 {
 749         const struct nfsd4_callback *cb = data;
 750         const struct nfsd4_copy *cp =
 751                 container_of(cb, struct nfsd4_copy, cp_cb);
 752         struct nfs4_cb_compound_hdr hdr = {
 753                 .ident = 0,
 754                 .minorversion = cb->cb_clp->cl_minorversion,
 755         };
 756
 757         encode_cb_compound4args(xdr, &hdr);
 758         encode_cb_sequence4args(xdr, cb, &hdr);
 759         encode_cb_offload4args(xdr, cp->nfserr, &cp->fh, cp, &hdr);
 760         encode_cb_nops(&hdr);
 761 }
 762
 763 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 764                                    struct xdr_stream *xdr,
 765                                    void *data)
 766 {
 767         struct nfsd4_callback *cb = data;
 768         struct nfs4_cb_compound_hdr hdr;
 769         int status;
 770
 771         status = decode_cb_compound4res(xdr, &hdr);
 772         if (unlikely(status))
 773                 return status;
 774
 775         if (cb) {
 776                 status = decode_cb_sequence4res(xdr, cb);
 777                 if (unlikely(status || cb->cb_seq_status))
 778                         return status;
 779         }
 780         return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 781 }
 782 /*
 783  * RPC procedure tables
 784  */
 785 #define PROC(proc, call, argtype, restype)                              \
 786 [NFSPROC4_CLNT_##proc] = {                                              \
 787         .p_proc    = NFSPROC4_CB_##call,                                \
 788         .p_encode  = nfs4_xdr_enc_##argtype,            \
 789         .p_decode  = nfs4_xdr_dec_##restype,                            \
 790         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 791         .p_replen  = NFS4_dec_##restype##_sz,                           \
 792         .p_statidx = NFSPROC4_CB_##call,                                \
 793         .p_name    = #proc,                                             \
 794 }
 795
 796 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 797         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 798         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 799 #ifdef CONFIG_NFSD_PNFS
 800         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 801 #endif
 802         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 803         PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 804 };
 805
 806 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 807 static const struct rpc_version nfs_cb_version4 = {
 808 /*
 809  * Note on the callback rpc program version number: despite language in rfc
 810  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 811  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 812  * in practice that appears to be what implementations use.  The section
 813  * 18.36.3 language is expected to be fixed in an erratum.
 814  */
 815         .number                 = 1,
 816         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 817         .procs                  = nfs4_cb_procedures,
 818         .counts                 = nfs4_cb_counts,
 819 };
 820
 821 static const struct rpc_version *nfs_cb_version[2] = {
 822         [1] = &nfs_cb_version4,
 823 };
 824
 825 static const struct rpc_program cb_program;
 826
 827 static struct rpc_stat cb_stats = {
 828         .program                = &cb_program
 829 };
 830
 831 #define NFS4_CALLBACK 0x40000000
 832 static const struct rpc_program cb_program = {
 833         .name                   = "nfs4_cb",
 834         .number                 = NFS4_CALLBACK,
 835         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 836         .version                = nfs_cb_version,
 837         .stats                  = &cb_stats,
 838         .pipe_dir_name          = "nfsd4_cb",
 839 };
 840
 841 static int max_cb_time(struct net *net)
 842 {
 843         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 844         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 845 }
 846
 847 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 848 {
 849         if (clp->cl_minorversion == 0) {
 850                 char *principal = clp->cl_cred.cr_targ_princ ?
 851                                         clp->cl_cred.cr_targ_princ : "nfs";
 852                 struct rpc_cred *cred;
 853
 854                 cred = rpc_lookup_machine_cred(principal);
 855                 if (!IS_ERR(cred))
 856                         get_rpccred(cred);
 857                 return cred;
 858         } else {
 859                 struct rpc_auth *auth = client->cl_auth;
 860                 struct auth_cred acred = {};
 861
 862                 acred.uid = ses->se_cb_sec.uid;
 863                 acred.gid = ses->se_cb_sec.gid;
 864                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
 865         }
 866 }
 867
 868 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 869 {
 870         int maxtime = max_cb_time(clp->net);
 871         struct rpc_timeout      timeparms = {
 872                 .to_initval     = maxtime,
 873                 .to_retries     = 0,
 874                 .to_maxval      = maxtime,
 875         };
 876         struct rpc_create_args args = {
 877                 .net            = clp->net,
 878                 .address        = (struct sockaddr *) &conn->cb_addr,
 879                 .addrsize       = conn->cb_addrlen,
 880                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 881                 .timeout        = &timeparms,
 882                 .program        = &cb_program,
 883                 .version        = 1,
 884                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 885         };
 886         struct rpc_clnt *client;
 887         struct rpc_cred *cred;
 888
 889         if (clp->cl_minorversion == 0) {
 890                 if (!clp->cl_cred.cr_principal &&
 891                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 892                         return -EINVAL;
 893                 args.client_name = clp->cl_cred.cr_principal;
 894                 args.prognumber = conn->cb_prog;
 895                 args.protocol = XPRT_TRANSPORT_TCP;
 896                 args.authflavor = clp->cl_cred.cr_flavor;
 897                 clp->cl_cb_ident = conn->cb_ident;
 898         } else {
 899                 if (!conn->cb_xprt)
 900                         return -EINVAL;
 901                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 902                 clp->cl_cb_session = ses;
 903                 args.bc_xprt = conn->cb_xprt;
 904                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 905                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 906                                 XPRT_TRANSPORT_BC;
 907                 args.authflavor = ses->se_cb_sec.flavor;
 908         }
 909         /* Create RPC client */
 910         client = rpc_create(&args);
 911         if (IS_ERR(client)) {
 912                 dprintk("NFSD: couldn't create callback client: %ld\n",
 913                         PTR_ERR(client));
 914                 return PTR_ERR(client);
 915         }
 916         cred = get_backchannel_cred(clp, client, ses);
 917         if (IS_ERR(cred)) {
 918                 rpc_shutdown_client(client);
 919                 return PTR_ERR(cred);
 920         }
 921         clp->cl_cb_client = client;
 922         clp->cl_cb_cred = cred;
 923         return 0;
 924 }
 925
 926 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 927 {
 928         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 929                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 930 }
 931
 932 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 933 {
 934         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 935                 return;
 936         clp->cl_cb_state = NFSD4_CB_DOWN;
 937         warn_no_callback_path(clp, reason);
 938 }
 939
 940 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 941 {
 942         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 943                 return;
 944         clp->cl_cb_state = NFSD4_CB_FAULT;
 945         warn_no_callback_path(clp, reason);
 946 }
 947
 948 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 949 {
 950         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 951
 952         if (task->tk_status)
 953                 nfsd4_mark_cb_down(clp, task->tk_status);
 954         else
 955                 clp->cl_cb_state = NFSD4_CB_UP;
 956 }
 957
 958 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 959         /* XXX: release method to ensure we set the cb channel down if
 960          * necessary on early failure? */
 961         .rpc_call_done = nfsd4_cb_probe_done,
 962 };
 963
 964 static struct workqueue_struct *callback_wq;
 965
 966 /*
 967  * Poke the callback thread to process any updates to the callback
 968  * parameters, and send a null probe.
 969  */
 970 void nfsd4_probe_callback(struct nfs4_client *clp)
 971 {
 972         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 973         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 974         nfsd4_run_cb(&clp->cl_cb_null);
 975 }
 976
 977 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 978 {
 979         nfsd4_probe_callback(clp);
 980         flush_workqueue(callback_wq);
 981 }
 982
 983 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 984 {
 985         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 986         spin_lock(&clp->cl_lock);
 987         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 988         spin_unlock(&clp->cl_lock);
 989 }
 990
 991 /*
 992  * There's currently a single callback channel slot.
 993  * If the slot is available, then mark it busy.  Otherwise, set the
 994  * thread for sleeping on the callback RPC wait queue.
 995  */
 996 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 997 {
 998         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 999                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1000                 /* Race breaker */
1001                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1002                         dprintk("%s slot is busy\n", __func__);
1003                         return false;
1004                 }
1005                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1006         }
1007         return true;
1008 }
1009
1010 /*
1011  * TODO: cb_sequence should support referring call lists, cachethis, multiple
1012  * slots, and mark callback channel down on communication errors.
1013  */
1014 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1015 {
1016         struct nfsd4_callback *cb = calldata;
1017         struct nfs4_client *clp = cb->cb_clp;
1018         u32 minorversion = clp->cl_minorversion;
1019
1020         /*
1021          * cb_seq_status is only set in decode_cb_sequence4res,
1022          * and so will remain 1 if an rpc level failure occurs.
1023          */
1024         cb->cb_seq_status = 1;
1025         cb->cb_status = 0;
1026         if (minorversion) {
1027                 if (!nfsd41_cb_get_slot(clp, task))
1028                         return;
1029         }
1030         rpc_call_start(task);
1031 }
1032
1033 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1034 {
1035         struct nfs4_client *clp = cb->cb_clp;
1036         struct nfsd4_session *session = clp->cl_cb_session;
1037         bool ret = true;
1038
1039         if (!clp->cl_minorversion) {
1040                 /*
1041                  * If the backchannel connection was shut down while this
1042                  * task was queued, we need to resubmit it after setting up
1043                  * a new backchannel connection.
1044                  *
1045                  * Note that if we lost our callback connection permanently
1046                  * the submission code will error out, so we don't need to
1047                  * handle that case here.
1048                  */
1049                 if (task->tk_flags & RPC_TASK_KILLED)
1050                         goto need_restart;
1051
1052                 return true;
1053         }
1054
1055         switch (cb->cb_seq_status) {
1056         case 0:
1057                 /*
1058                  * No need for lock, access serialized in nfsd4_cb_prepare
1059                  *
1060                  * RFC5661 20.9.3
1061                  * If CB_SEQUENCE returns an error, then the state of the slot
1062                  * (sequence ID, cached reply) MUST NOT change.
1063                  */
1064                 ++session->se_cb_seq_nr;
1065                 break;
1066         case -ESERVERFAULT:
1067                 ++session->se_cb_seq_nr;
1068                 /* Fall through */
1069         case 1:
1070         case -NFS4ERR_BADSESSION:
1071                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1072                 ret = false;
1073                 break;
1074         case -NFS4ERR_DELAY:
1075                 if (!rpc_restart_call(task))
1076                         goto out;
1077
1078                 rpc_delay(task, 2 * HZ);
1079                 return false;
1080         case -NFS4ERR_BADSLOT:
1081                 goto retry_nowait;
1082         case -NFS4ERR_SEQ_MISORDERED:
1083                 if (session->se_cb_seq_nr != 1) {
1084                         session->se_cb_seq_nr = 1;
1085                         goto retry_nowait;
1086                 }
1087                 break;
1088         default:
1089                 dprintk("%s: unprocessed error %d\n", __func__,
1090                         cb->cb_seq_status);
1091         }
1092
1093         clear_bit(0, &clp->cl_cb_slot_busy);
1094         rpc_wake_up_next(&clp->cl_cb_waitq);
1095         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1096                 clp->cl_cb_session->se_cb_seq_nr);
1097
1098         if (task->tk_flags & RPC_TASK_KILLED)
1099                 goto need_restart;
1100 out:
1101         return ret;
1102 retry_nowait:
1103         if (rpc_restart_call_prepare(task))
1104                 ret = false;
1105         goto out;
1106 need_restart:
1107         task->tk_status = 0;
1108         cb->cb_need_restart = true;
1109         return false;
1110 }
1111
1112 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1113 {
1114         struct nfsd4_callback *cb = calldata;
1115         struct nfs4_client *clp = cb->cb_clp;
1116
1117         dprintk("%s: minorversion=%d\n", __func__,
1118                 clp->cl_minorversion);
1119
1120         if (!nfsd4_cb_sequence_done(task, cb))
1121                 return;
1122
1123         if (cb->cb_status) {
1124                 WARN_ON_ONCE(task->tk_status);
1125                 task->tk_status = cb->cb_status;
1126         }
1127
1128         switch (cb->cb_ops->done(cb, task)) {
1129         case 0:
1130                 task->tk_status = 0;
1131                 rpc_restart_call_prepare(task);
1132                 return;
1133         case 1:
1134                 break;
1135         case -1:
1136                 /* Network partition? */
1137                 nfsd4_mark_cb_down(clp, task->tk_status);
1138                 break;
1139         default:
1140                 BUG();
1141         }
1142 }
1143
1144 static void nfsd4_cb_release(void *calldata)
1145 {
1146         struct nfsd4_callback *cb = calldata;
1147
1148         if (cb->cb_need_restart)
1149                 nfsd4_run_cb(cb);
1150         else
1151                 cb->cb_ops->release(cb);
1152
1153 }
1154
1155 static const struct rpc_call_ops nfsd4_cb_ops = {
1156         .rpc_call_prepare = nfsd4_cb_prepare,
1157         .rpc_call_done = nfsd4_cb_done,
1158         .rpc_release = nfsd4_cb_release,
1159 };
1160
1161 int nfsd4_create_callback_queue(void)
1162 {
1163         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1164         if (!callback_wq)
1165                 return -ENOMEM;
1166         return 0;
1167 }
1168
1169 void nfsd4_destroy_callback_queue(void)
1170 {
1171         destroy_workqueue(callback_wq);
1172 }
1173
1174 /* must be called under the state lock */
1175 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1176 {
1177         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1178         /*
1179          * Note this won't actually result in a null callback;
1180          * instead, nfsd4_run_cb_null() will detect the killed
1181          * client, destroy the rpc client, and stop:
1182          */
1183         nfsd4_run_cb(&clp->cl_cb_null);
1184         flush_workqueue(callback_wq);
1185 }
1186
1187 /* requires cl_lock: */
1188 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1189 {
1190         struct nfsd4_session *s;
1191         struct nfsd4_conn *c;
1192
1193         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1194                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1195                         if (c->cn_flags & NFS4_CDFC4_BACK)
1196                                 return c;
1197                 }
1198         }
1199         return NULL;
1200 }
1201
1202 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1203 {
1204         struct nfs4_cb_conn conn;
1205         struct nfs4_client *clp = cb->cb_clp;
1206         struct nfsd4_session *ses = NULL;
1207         struct nfsd4_conn *c;
1208         int err;
1209
1210         /*
1211          * This is either an update, or the client dying; in either case,
1212          * kill the old client:
1213          */
1214         if (clp->cl_cb_client) {
1215                 rpc_shutdown_client(clp->cl_cb_client);
1216                 clp->cl_cb_client = NULL;
1217                 put_rpccred(clp->cl_cb_cred);
1218                 clp->cl_cb_cred = NULL;
1219         }
1220         if (clp->cl_cb_conn.cb_xprt) {
1221                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1222                 clp->cl_cb_conn.cb_xprt = NULL;
1223         }
1224         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1225                 return;
1226         spin_lock(&clp->cl_lock);
1227         /*
1228          * Only serialized callback code is allowed to clear these
1229          * flags; main nfsd code can only set them:
1230          */
1231         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1232         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1233         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1234         c = __nfsd4_find_backchannel(clp);
1235         if (c) {
1236                 svc_xprt_get(c->cn_xprt);
1237                 conn.cb_xprt = c->cn_xprt;
1238                 ses = c->cn_session;
1239         }
1240         spin_unlock(&clp->cl_lock);
1241
1242         err = setup_callback_client(clp, &conn, ses);
1243         if (err) {
1244                 nfsd4_mark_cb_down(clp, err);
1245                 return;
1246         }
1247 }
1248
1249 static void
1250 nfsd4_run_cb_work(struct work_struct *work)
1251 {
1252         struct nfsd4_callback *cb =
1253                 container_of(work, struct nfsd4_callback, cb_work);
1254         struct nfs4_client *clp = cb->cb_clp;
1255         struct rpc_clnt *clnt;
1256
1257         if (cb->cb_need_restart) {
1258                 cb->cb_need_restart = false;
1259         } else {
1260                 if (cb->cb_ops && cb->cb_ops->prepare)
1261                         cb->cb_ops->prepare(cb);
1262         }
1263
1264         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1265                 nfsd4_process_cb_update(cb);
1266
1267         clnt = clp->cl_cb_client;
1268         if (!clnt) {
1269                 /* Callback channel broken, or client killed; give up: */
1270                 if (cb->cb_ops && cb->cb_ops->release)
1271                         cb->cb_ops->release(cb);
1272                 return;
1273         }
1274
1275         /*
1276          * Don't send probe messages for 4.1 or later.
1277          */
1278         if (!cb->cb_ops && clp->cl_minorversion) {
1279                 clp->cl_cb_state = NFSD4_CB_UP;
1280                 return;
1281         }
1282
1283         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1284         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1285                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1286 }
1287
1288 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1289                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1290 {
1291         cb->cb_clp = clp;
1292         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1293         cb->cb_msg.rpc_argp = cb;
1294         cb->cb_msg.rpc_resp = cb;
1295         cb->cb_ops = ops;
1296         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1297         cb->cb_seq_status = 1;
1298         cb->cb_status = 0;
1299         cb->cb_need_restart = false;
1300 }
1301
1302 void nfsd4_run_cb(struct nfsd4_callback *cb)
1303 {
1304         queue_work(callback_wq, &cb->cb_work);
1305 }