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 "trace.h"
  42 #include "xdr4cb.h"
  43 #include "xdr4.h"
  44
  45 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  46
  47 static 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
  54 struct 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
  64 static __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  */
  87 enum 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
 104 static 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  */
 117 static 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_raw, length);
 125 }
 126
 127 /*
 128  * stateid4
 129  *
 130  *      struct stateid4 {
 131  *              uint32_t        seqid;
 132  *              opaque          other[12];
 133  *      };
 134  */
 135 static 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  */
 149 static 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  */
 162 static 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  */
 206 static 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
 219 static 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;
 233 out_overflow:
 234         return -EIO;
 235 out_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 */
 251 static 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  */
 268 static 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  */
 283 static 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;
 301 out_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  */
 314 static 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  */
 343 static 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  */
 387 static 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;
 425 out:
 426         cb->cb_seq_status = status;
 427         return status;
 428 out_overflow:
 429         status = -EIO;
 430         goto out;
 431 }
 432
 433 static 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  */
 460 static 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  */
 469 static 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
 495 static 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  */
 504 static 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  */
 550 static 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
 576 static 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
 594 static 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
 614 static 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
 623 static 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
 652 static 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  */
 690 static void encode_offload_info4(struct xdr_stream *xdr,
 691                                  const struct nfsd4_cb_offload *cbo)
 692 {
 693         __be32 *p;
 694
 695         p = xdr_reserve_space(xdr, 4);
 696         *p = cbo->co_nfserr;
 697         switch (cbo->co_nfserr) {
 698         case nfs_ok:
 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, cbo->co_res.wr_bytes_written);
 702                 *p++ = cpu_to_be32(cbo->co_res.wr_stable_how);
 703                 p = xdr_encode_opaque_fixed(p, cbo->co_res.wr_verifier.data,
 704                                             NFS4_VERIFIER_SIZE);
 705                 break;
 706         default:
 707                 p = xdr_reserve_space(xdr, 8);
 708                 /* We always return success if bytes were written */
 709                 p = xdr_encode_hyper(p, 0);
 710         }
 711 }
 712
 713 static void encode_cb_offload4args(struct xdr_stream *xdr,
 714                                    const struct nfsd4_cb_offload *cbo,
 715                                    struct nfs4_cb_compound_hdr *hdr)
 716 {
 717         __be32 *p;
 718
 719         p = xdr_reserve_space(xdr, 4);
 720         *p = cpu_to_be32(OP_CB_OFFLOAD);
 721         encode_nfs_fh4(xdr, &cbo->co_fh);
 722         encode_stateid4(xdr, &cbo->co_res.cb_stateid);
 723         encode_offload_info4(xdr, cbo);
 724
 725         hdr->nops++;
 726 }
 727
 728 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 729                                     struct xdr_stream *xdr,
 730                                     const void *data)
 731 {
 732         const struct nfsd4_callback *cb = data;
 733         const struct nfsd4_cb_offload *cbo =
 734                 container_of(cb, struct nfsd4_cb_offload, co_cb);
 735         struct nfs4_cb_compound_hdr hdr = {
 736                 .ident = 0,
 737                 .minorversion = cb->cb_clp->cl_minorversion,
 738         };
 739
 740         encode_cb_compound4args(xdr, &hdr);
 741         encode_cb_sequence4args(xdr, cb, &hdr);
 742         encode_cb_offload4args(xdr, cbo, &hdr);
 743         encode_cb_nops(&hdr);
 744 }
 745
 746 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 747                                    struct xdr_stream *xdr,
 748                                    void *data)
 749 {
 750         struct nfsd4_callback *cb = data;
 751         struct nfs4_cb_compound_hdr hdr;
 752         int status;
 753
 754         status = decode_cb_compound4res(xdr, &hdr);
 755         if (unlikely(status))
 756                 return status;
 757
 758         status = decode_cb_sequence4res(xdr, cb);
 759         if (unlikely(status || cb->cb_seq_status))
 760                 return status;
 761
 762         return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 763 }
 764 /*
 765  * RPC procedure tables
 766  */
 767 #define PROC(proc, call, argtype, restype)                              \
 768 [NFSPROC4_CLNT_##proc] = {                                              \
 769         .p_proc    = NFSPROC4_CB_##call,                                \
 770         .p_encode  = nfs4_xdr_enc_##argtype,            \
 771         .p_decode  = nfs4_xdr_dec_##restype,                            \
 772         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 773         .p_replen  = NFS4_dec_##restype##_sz,                           \
 774         .p_statidx = NFSPROC4_CB_##call,                                \
 775         .p_name    = #proc,                                             \
 776 }
 777
 778 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 779         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 780         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 781 #ifdef CONFIG_NFSD_PNFS
 782         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 783 #endif
 784         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 785         PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 786 };
 787
 788 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 789 static const struct rpc_version nfs_cb_version4 = {
 790 /*
 791  * Note on the callback rpc program version number: despite language in rfc
 792  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 793  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 794  * in practice that appears to be what implementations use.  The section
 795  * 18.36.3 language is expected to be fixed in an erratum.
 796  */
 797         .number                 = 1,
 798         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 799         .procs                  = nfs4_cb_procedures,
 800         .counts                 = nfs4_cb_counts,
 801 };
 802
 803 static const struct rpc_version *nfs_cb_version[2] = {
 804         [1] = &nfs_cb_version4,
 805 };
 806
 807 static const struct rpc_program cb_program;
 808
 809 static struct rpc_stat cb_stats = {
 810         .program                = &cb_program
 811 };
 812
 813 #define NFS4_CALLBACK 0x40000000
 814 static const struct rpc_program cb_program = {
 815         .name                   = "nfs4_cb",
 816         .number                 = NFS4_CALLBACK,
 817         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 818         .version                = nfs_cb_version,
 819         .stats                  = &cb_stats,
 820         .pipe_dir_name          = "nfsd4_cb",
 821 };
 822
 823 static int max_cb_time(struct net *net)
 824 {
 825         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 826
 827         /*
 828          * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
 829          * so we can use 32-bit math on it. Warn if that assumption
 830          * ever stops being true.
 831          */
 832         if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
 833                 return 360 * HZ;
 834
 835         return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
 836 }
 837
 838 static struct workqueue_struct *callback_wq;
 839
 840 static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
 841 {
 842         return queue_work(callback_wq, &cb->cb_work);
 843 }
 844
 845 static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
 846 {
 847         atomic_inc(&clp->cl_cb_inflight);
 848 }
 849
 850 static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
 851 {
 852
 853         if (atomic_dec_and_test(&clp->cl_cb_inflight))
 854                 wake_up_var(&clp->cl_cb_inflight);
 855 }
 856
 857 static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
 858 {
 859         wait_var_event(&clp->cl_cb_inflight,
 860                         !atomic_read(&clp->cl_cb_inflight));
 861 }
 862
 863 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 864 {
 865         if (clp->cl_minorversion == 0) {
 866                 client->cl_principal = clp->cl_cred.cr_targ_princ ?
 867                         clp->cl_cred.cr_targ_princ : "nfs";
 868
 869                 return get_cred(rpc_machine_cred());
 870         } else {
 871                 struct cred *kcred;
 872
 873                 kcred = prepare_kernel_cred(NULL);
 874                 if (!kcred)
 875                         return NULL;
 876
 877                 kcred->uid = ses->se_cb_sec.uid;
 878                 kcred->gid = ses->se_cb_sec.gid;
 879                 return kcred;
 880         }
 881 }
 882
 883 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 884 {
 885         int maxtime = max_cb_time(clp->net);
 886         struct rpc_timeout      timeparms = {
 887                 .to_initval     = maxtime,
 888                 .to_retries     = 0,
 889                 .to_maxval      = maxtime,
 890         };
 891         struct rpc_create_args args = {
 892                 .net            = clp->net,
 893                 .address        = (struct sockaddr *) &conn->cb_addr,
 894                 .addrsize       = conn->cb_addrlen,
 895                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 896                 .timeout        = &timeparms,
 897                 .program        = &cb_program,
 898                 .version        = 1,
 899                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 900                 .cred           = current_cred(),
 901         };
 902         struct rpc_clnt *client;
 903         const struct cred *cred;
 904
 905         if (clp->cl_minorversion == 0) {
 906                 if (!clp->cl_cred.cr_principal &&
 907                     (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
 908                         trace_nfsd_cb_setup_err(clp, -EINVAL);
 909                         return -EINVAL;
 910                 }
 911                 args.client_name = clp->cl_cred.cr_principal;
 912                 args.prognumber = conn->cb_prog;
 913                 args.protocol = XPRT_TRANSPORT_TCP;
 914                 args.authflavor = clp->cl_cred.cr_flavor;
 915                 clp->cl_cb_ident = conn->cb_ident;
 916         } else {
 917                 if (!conn->cb_xprt)
 918                         return -EINVAL;
 919                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 920                 clp->cl_cb_session = ses;
 921                 args.bc_xprt = conn->cb_xprt;
 922                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 923                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 924                                 XPRT_TRANSPORT_BC;
 925                 args.authflavor = ses->se_cb_sec.flavor;
 926         }
 927         /* Create RPC client */
 928         client = rpc_create(&args);
 929         if (IS_ERR(client)) {
 930                 trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
 931                 return PTR_ERR(client);
 932         }
 933         cred = get_backchannel_cred(clp, client, ses);
 934         if (!cred) {
 935                 trace_nfsd_cb_setup_err(clp, -ENOMEM);
 936                 rpc_shutdown_client(client);
 937                 return -ENOMEM;
 938         }
 939         clp->cl_cb_client = client;
 940         clp->cl_cb_cred = cred;
 941         rcu_read_lock();
 942         trace_nfsd_cb_setup(clp, rpc_peeraddr2str(client, RPC_DISPLAY_NETID),
 943                             args.authflavor);
 944         rcu_read_unlock();
 945         return 0;
 946 }
 947
 948 static void nfsd4_mark_cb_state(struct nfs4_client *clp, int newstate)
 949 {
 950         if (clp->cl_cb_state != newstate) {
 951                 clp->cl_cb_state = newstate;
 952                 trace_nfsd_cb_state(clp);
 953         }
 954 }
 955
 956 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 957 {
 958         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 959                 return;
 960         nfsd4_mark_cb_state(clp, NFSD4_CB_DOWN);
 961 }
 962
 963 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 964 {
 965         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 966                 return;
 967         nfsd4_mark_cb_state(clp, NFSD4_CB_FAULT);
 968 }
 969
 970 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 971 {
 972         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 973
 974         if (task->tk_status)
 975                 nfsd4_mark_cb_down(clp, task->tk_status);
 976         else
 977                 nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
 978 }
 979
 980 static void nfsd4_cb_probe_release(void *calldata)
 981 {
 982         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 983
 984         nfsd41_cb_inflight_end(clp);
 985
 986 }
 987
 988 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 989         /* XXX: release method to ensure we set the cb channel down if
 990          * necessary on early failure? */
 991         .rpc_call_done = nfsd4_cb_probe_done,
 992         .rpc_release = nfsd4_cb_probe_release,
 993 };
 994
 995 /*
 996  * Poke the callback thread to process any updates to the callback
 997  * parameters, and send a null probe.
 998  */
 999 void nfsd4_probe_callback(struct nfs4_client *clp)
1000 {
1001         trace_nfsd_cb_probe(clp);
1002         nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1003         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1004         nfsd4_run_cb(&clp->cl_cb_null);
1005 }
1006
1007 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
1008 {
1009         nfsd4_probe_callback(clp);
1010         flush_workqueue(callback_wq);
1011 }
1012
1013 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
1014 {
1015         nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1016         spin_lock(&clp->cl_lock);
1017         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
1018         spin_unlock(&clp->cl_lock);
1019 }
1020
1021 /*
1022  * There's currently a single callback channel slot.
1023  * If the slot is available, then mark it busy.  Otherwise, set the
1024  * thread for sleeping on the callback RPC wait queue.
1025  */
1026 static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
1027 {
1028         struct nfs4_client *clp = cb->cb_clp;
1029
1030         if (!cb->cb_holds_slot &&
1031             test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1032                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1033                 /* Race breaker */
1034                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1035                         dprintk("%s slot is busy\n", __func__);
1036                         return false;
1037                 }
1038                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1039         }
1040         cb->cb_holds_slot = true;
1041         return true;
1042 }
1043
1044 static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
1045 {
1046         struct nfs4_client *clp = cb->cb_clp;
1047
1048         if (cb->cb_holds_slot) {
1049                 cb->cb_holds_slot = false;
1050                 clear_bit(0, &clp->cl_cb_slot_busy);
1051                 rpc_wake_up_next(&clp->cl_cb_waitq);
1052         }
1053 }
1054
1055 static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
1056 {
1057         struct nfs4_client *clp = cb->cb_clp;
1058
1059         nfsd41_cb_release_slot(cb);
1060         if (cb->cb_ops && cb->cb_ops->release)
1061                 cb->cb_ops->release(cb);
1062         nfsd41_cb_inflight_end(clp);
1063 }
1064
1065 /*
1066  * TODO: cb_sequence should support referring call lists, cachethis, multiple
1067  * slots, and mark callback channel down on communication errors.
1068  */
1069 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1070 {
1071         struct nfsd4_callback *cb = calldata;
1072         struct nfs4_client *clp = cb->cb_clp;
1073         u32 minorversion = clp->cl_minorversion;
1074
1075         /*
1076          * cb_seq_status is only set in decode_cb_sequence4res,
1077          * and so will remain 1 if an rpc level failure occurs.
1078          */
1079         cb->cb_seq_status = 1;
1080         cb->cb_status = 0;
1081         if (minorversion && !nfsd41_cb_get_slot(cb, task))
1082                 return;
1083         rpc_call_start(task);
1084 }
1085
1086 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1087 {
1088         struct nfs4_client *clp = cb->cb_clp;
1089         struct nfsd4_session *session = clp->cl_cb_session;
1090         bool ret = true;
1091
1092         if (!clp->cl_minorversion) {
1093                 /*
1094                  * If the backchannel connection was shut down while this
1095                  * task was queued, we need to resubmit it after setting up
1096                  * a new backchannel connection.
1097                  *
1098                  * Note that if we lost our callback connection permanently
1099                  * the submission code will error out, so we don't need to
1100                  * handle that case here.
1101                  */
1102                 if (RPC_SIGNALLED(task))
1103                         goto need_restart;
1104
1105                 return true;
1106         }
1107
1108         if (!cb->cb_holds_slot)
1109                 goto need_restart;
1110
1111         switch (cb->cb_seq_status) {
1112         case 0:
1113                 /*
1114                  * No need for lock, access serialized in nfsd4_cb_prepare
1115                  *
1116                  * RFC5661 20.9.3
1117                  * If CB_SEQUENCE returns an error, then the state of the slot
1118                  * (sequence ID, cached reply) MUST NOT change.
1119                  */
1120                 ++session->se_cb_seq_nr;
1121                 break;
1122         case -ESERVERFAULT:
1123                 ++session->se_cb_seq_nr;
1124                 fallthrough;
1125         case 1:
1126         case -NFS4ERR_BADSESSION:
1127                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1128                 ret = false;
1129                 break;
1130         case -NFS4ERR_DELAY:
1131                 if (!rpc_restart_call(task))
1132                         goto out;
1133
1134                 rpc_delay(task, 2 * HZ);
1135                 return false;
1136         case -NFS4ERR_BADSLOT:
1137                 goto retry_nowait;
1138         case -NFS4ERR_SEQ_MISORDERED:
1139                 if (session->se_cb_seq_nr != 1) {
1140                         session->se_cb_seq_nr = 1;
1141                         goto retry_nowait;
1142                 }
1143                 break;
1144         default:
1145                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1146                 dprintk("%s: unprocessed error %d\n", __func__,
1147                         cb->cb_seq_status);
1148         }
1149
1150         nfsd41_cb_release_slot(cb);
1151         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1152                 clp->cl_cb_session->se_cb_seq_nr);
1153
1154         if (RPC_SIGNALLED(task))
1155                 goto need_restart;
1156 out:
1157         return ret;
1158 retry_nowait:
1159         if (rpc_restart_call_prepare(task))
1160                 ret = false;
1161         goto out;
1162 need_restart:
1163         if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
1164                 task->tk_status = 0;
1165                 cb->cb_need_restart = true;
1166         }
1167         return false;
1168 }
1169
1170 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1171 {
1172         struct nfsd4_callback *cb = calldata;
1173         struct nfs4_client *clp = cb->cb_clp;
1174
1175         if (!nfsd4_cb_sequence_done(task, cb))
1176                 return;
1177
1178         if (cb->cb_status) {
1179                 WARN_ON_ONCE(task->tk_status);
1180                 task->tk_status = cb->cb_status;
1181         }
1182
1183         switch (cb->cb_ops->done(cb, task)) {
1184         case 0:
1185                 task->tk_status = 0;
1186                 rpc_restart_call_prepare(task);
1187                 return;
1188         case 1:
1189                 switch (task->tk_status) {
1190                 case -EIO:
1191                 case -ETIMEDOUT:
1192                 case -EACCES:
1193                         nfsd4_mark_cb_down(clp, task->tk_status);
1194                 }
1195                 break;
1196         default:
1197                 BUG();
1198         }
1199 }
1200
1201 static void nfsd4_cb_release(void *calldata)
1202 {
1203         struct nfsd4_callback *cb = calldata;
1204
1205         if (cb->cb_need_restart)
1206                 nfsd4_queue_cb(cb);
1207         else
1208                 nfsd41_destroy_cb(cb);
1209
1210 }
1211
1212 static const struct rpc_call_ops nfsd4_cb_ops = {
1213         .rpc_call_prepare = nfsd4_cb_prepare,
1214         .rpc_call_done = nfsd4_cb_done,
1215         .rpc_release = nfsd4_cb_release,
1216 };
1217
1218 int nfsd4_create_callback_queue(void)
1219 {
1220         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1221         if (!callback_wq)
1222                 return -ENOMEM;
1223         return 0;
1224 }
1225
1226 void nfsd4_destroy_callback_queue(void)
1227 {
1228         destroy_workqueue(callback_wq);
1229 }
1230
1231 /* must be called under the state lock */
1232 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1233 {
1234         if (clp->cl_cb_state != NFSD4_CB_UNKNOWN)
1235                 trace_nfsd_cb_shutdown(clp);
1236
1237         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1238         /*
1239          * Note this won't actually result in a null callback;
1240          * instead, nfsd4_run_cb_null() will detect the killed
1241          * client, destroy the rpc client, and stop:
1242          */
1243         nfsd4_run_cb(&clp->cl_cb_null);
1244         flush_workqueue(callback_wq);
1245         nfsd41_cb_inflight_wait_complete(clp);
1246 }
1247
1248 /* requires cl_lock: */
1249 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1250 {
1251         struct nfsd4_session *s;
1252         struct nfsd4_conn *c;
1253
1254         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1255                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1256                         if (c->cn_flags & NFS4_CDFC4_BACK)
1257                                 return c;
1258                 }
1259         }
1260         return NULL;
1261 }
1262
1263 /*
1264  * Note there isn't a lot of locking in this code; instead we depend on
1265  * the fact that it is run from the callback_wq, which won't run two
1266  * work items at once.  So, for example, callback_wq handles all access
1267  * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
1268  */
1269 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1270 {
1271         struct nfs4_cb_conn conn;
1272         struct nfs4_client *clp = cb->cb_clp;
1273         struct nfsd4_session *ses = NULL;
1274         struct nfsd4_conn *c;
1275         int err;
1276
1277         /*
1278          * This is either an update, or the client dying; in either case,
1279          * kill the old client:
1280          */
1281         if (clp->cl_cb_client) {
1282                 rpc_shutdown_client(clp->cl_cb_client);
1283                 clp->cl_cb_client = NULL;
1284                 put_cred(clp->cl_cb_cred);
1285                 clp->cl_cb_cred = NULL;
1286         }
1287         if (clp->cl_cb_conn.cb_xprt) {
1288                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1289                 clp->cl_cb_conn.cb_xprt = NULL;
1290         }
1291         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1292                 return;
1293         spin_lock(&clp->cl_lock);
1294         /*
1295          * Only serialized callback code is allowed to clear these
1296          * flags; main nfsd code can only set them:
1297          */
1298         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1299         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1300         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1301         c = __nfsd4_find_backchannel(clp);
1302         if (c) {
1303                 svc_xprt_get(c->cn_xprt);
1304                 conn.cb_xprt = c->cn_xprt;
1305                 ses = c->cn_session;
1306         }
1307         spin_unlock(&clp->cl_lock);
1308
1309         err = setup_callback_client(clp, &conn, ses);
1310         if (err) {
1311                 nfsd4_mark_cb_down(clp, err);
1312                 if (c)
1313                         svc_xprt_put(c->cn_xprt);
1314                 return;
1315         }
1316 }
1317
1318 static void
1319 nfsd4_run_cb_work(struct work_struct *work)
1320 {
1321         struct nfsd4_callback *cb =
1322                 container_of(work, struct nfsd4_callback, cb_work);
1323         struct nfs4_client *clp = cb->cb_clp;
1324         struct rpc_clnt *clnt;
1325         int flags;
1326
1327         if (cb->cb_need_restart) {
1328                 cb->cb_need_restart = false;
1329         } else {
1330                 if (cb->cb_ops && cb->cb_ops->prepare)
1331                         cb->cb_ops->prepare(cb);
1332         }
1333
1334         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1335                 nfsd4_process_cb_update(cb);
1336
1337         clnt = clp->cl_cb_client;
1338         if (!clnt) {
1339                 /* Callback channel broken, or client killed; give up: */
1340                 nfsd41_destroy_cb(cb);
1341                 return;
1342         }
1343
1344         /*
1345          * Don't send probe messages for 4.1 or later.
1346          */
1347         if (!cb->cb_ops && clp->cl_minorversion) {
1348                 nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1349                 nfsd41_destroy_cb(cb);
1350                 return;
1351         }
1352
1353         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1354         flags = clp->cl_minorversion ? RPC_TASK_NOCONNECT : RPC_TASK_SOFTCONN;
1355         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | flags,
1356                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1357 }
1358
1359 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1360                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1361 {
1362         cb->cb_clp = clp;
1363         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1364         cb->cb_msg.rpc_argp = cb;
1365         cb->cb_msg.rpc_resp = cb;
1366         cb->cb_ops = ops;
1367         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1368         cb->cb_seq_status = 1;
1369         cb->cb_status = 0;
1370         cb->cb_need_restart = false;
1371         cb->cb_holds_slot = false;
1372 }
1373
1374 /**
1375  * nfsd4_run_cb - queue up a callback job to run
1376  * @cb: callback to queue
1377  *
1378  * Kick off a callback to do its thing. Returns false if it was already
1379  * on a queue, true otherwise.
1380  */
1381 bool nfsd4_run_cb(struct nfsd4_callback *cb)
1382 {
1383         struct nfs4_client *clp = cb->cb_clp;
1384         bool queued;
1385
1386         nfsd41_cb_inflight_begin(clp);
1387         queued = nfsd4_queue_cb(cb);
1388         if (!queued)
1389                 nfsd41_cb_inflight_end(clp);
1390         return queued;
1391 }