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_base, 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                                  __be32 nfserr,
 692                                  const struct nfsd4_copy *cp)
 693 {
 694         __be32 *p;
 695
 696         p = xdr_reserve_space(xdr, 4);
 697         *p++ = nfserr;
 698         if (!nfserr) {
 699                 p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
 700                 p = xdr_encode_empty_array(p);
 701                 p = xdr_encode_hyper(p, cp->cp_res.wr_bytes_written);
 702                 *p++ = cpu_to_be32(cp->cp_res.wr_stable_how);
 703                 p = xdr_encode_opaque_fixed(p, cp->cp_res.wr_verifier.data,
 704                                             NFS4_VERIFIER_SIZE);
 705         } else {
 706                 p = xdr_reserve_space(xdr, 8);
 707                 /* We always return success if bytes were written */
 708                 p = xdr_encode_hyper(p, 0);
 709         }
 710 }
 711
 712 static void encode_cb_offload4args(struct xdr_stream *xdr,
 713                                    __be32 nfserr,
 714                                    const struct knfsd_fh *fh,
 715                                    const struct nfsd4_copy *cp,
 716                                    struct nfs4_cb_compound_hdr *hdr)
 717 {
 718         __be32 *p;
 719
 720         p = xdr_reserve_space(xdr, 4);
 721         *p++ = cpu_to_be32(OP_CB_OFFLOAD);
 722         encode_nfs_fh4(xdr, fh);
 723         encode_stateid4(xdr, &cp->cp_res.cb_stateid);
 724         encode_offload_info4(xdr, nfserr, cp);
 725
 726         hdr->nops++;
 727 }
 728
 729 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 730                                     struct xdr_stream *xdr,
 731                                     const void *data)
 732 {
 733         const struct nfsd4_callback *cb = data;
 734         const struct nfsd4_copy *cp =
 735                 container_of(cb, struct nfsd4_copy, cp_cb);
 736         struct nfs4_cb_compound_hdr hdr = {
 737                 .ident = 0,
 738                 .minorversion = cb->cb_clp->cl_minorversion,
 739         };
 740
 741         encode_cb_compound4args(xdr, &hdr);
 742         encode_cb_sequence4args(xdr, cb, &hdr);
 743         encode_cb_offload4args(xdr, cp->nfserr, &cp->fh, cp, &hdr);
 744         encode_cb_nops(&hdr);
 745 }
 746
 747 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 748                                    struct xdr_stream *xdr,
 749                                    void *data)
 750 {
 751         struct nfsd4_callback *cb = data;
 752         struct nfs4_cb_compound_hdr hdr;
 753         int status;
 754
 755         status = decode_cb_compound4res(xdr, &hdr);
 756         if (unlikely(status))
 757                 return status;
 758
 759         status = decode_cb_sequence4res(xdr, cb);
 760         if (unlikely(status || cb->cb_seq_status))
 761                 return status;
 762
 763         return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 764 }
 765 /*
 766  * RPC procedure tables
 767  */
 768 #define PROC(proc, call, argtype, restype)                              \
 769 [NFSPROC4_CLNT_##proc] = {                                              \
 770         .p_proc    = NFSPROC4_CB_##call,                                \
 771         .p_encode  = nfs4_xdr_enc_##argtype,            \
 772         .p_decode  = nfs4_xdr_dec_##restype,                            \
 773         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 774         .p_replen  = NFS4_dec_##restype##_sz,                           \
 775         .p_statidx = NFSPROC4_CB_##call,                                \
 776         .p_name    = #proc,                                             \
 777 }
 778
 779 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 780         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 781         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 782 #ifdef CONFIG_NFSD_PNFS
 783         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 784 #endif
 785         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 786         PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 787 };
 788
 789 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 790 static const struct rpc_version nfs_cb_version4 = {
 791 /*
 792  * Note on the callback rpc program version number: despite language in rfc
 793  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 794  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 795  * in practice that appears to be what implementations use.  The section
 796  * 18.36.3 language is expected to be fixed in an erratum.
 797  */
 798         .number                 = 1,
 799         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 800         .procs                  = nfs4_cb_procedures,
 801         .counts                 = nfs4_cb_counts,
 802 };
 803
 804 static const struct rpc_version *nfs_cb_version[2] = {
 805         [1] = &nfs_cb_version4,
 806 };
 807
 808 static const struct rpc_program cb_program;
 809
 810 static struct rpc_stat cb_stats = {
 811         .program                = &cb_program
 812 };
 813
 814 #define NFS4_CALLBACK 0x40000000
 815 static const struct rpc_program cb_program = {
 816         .name                   = "nfs4_cb",
 817         .number                 = NFS4_CALLBACK,
 818         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 819         .version                = nfs_cb_version,
 820         .stats                  = &cb_stats,
 821         .pipe_dir_name          = "nfsd4_cb",
 822 };
 823
 824 static int max_cb_time(struct net *net)
 825 {
 826         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 827
 828         /*
 829          * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
 830          * so we can use 32-bit math on it. Warn if that assumption
 831          * ever stops being true.
 832          */
 833         if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
 834                 return 360 * HZ;
 835
 836         return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
 837 }
 838
 839 static struct workqueue_struct *callback_wq;
 840
 841 static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
 842 {
 843         return queue_work(callback_wq, &cb->cb_work);
 844 }
 845
 846 static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
 847 {
 848         atomic_inc(&clp->cl_cb_inflight);
 849 }
 850
 851 static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
 852 {
 853
 854         if (atomic_dec_and_test(&clp->cl_cb_inflight))
 855                 wake_up_var(&clp->cl_cb_inflight);
 856 }
 857
 858 static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
 859 {
 860         wait_var_event(&clp->cl_cb_inflight,
 861                         !atomic_read(&clp->cl_cb_inflight));
 862 }
 863
 864 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 865 {
 866         if (clp->cl_minorversion == 0) {
 867                 client->cl_principal = clp->cl_cred.cr_targ_princ ?
 868                         clp->cl_cred.cr_targ_princ : "nfs";
 869
 870                 return get_cred(rpc_machine_cred());
 871         } else {
 872                 struct cred *kcred;
 873
 874                 kcred = prepare_kernel_cred(NULL);
 875                 if (!kcred)
 876                         return NULL;
 877
 878                 kcred->uid = ses->se_cb_sec.uid;
 879                 kcred->gid = ses->se_cb_sec.gid;
 880                 return kcred;
 881         }
 882 }
 883
 884 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 885 {
 886         int maxtime = max_cb_time(clp->net);
 887         struct rpc_timeout      timeparms = {
 888                 .to_initval     = maxtime,
 889                 .to_retries     = 0,
 890                 .to_maxval      = maxtime,
 891         };
 892         struct rpc_create_args args = {
 893                 .net            = clp->net,
 894                 .address        = (struct sockaddr *) &conn->cb_addr,
 895                 .addrsize       = conn->cb_addrlen,
 896                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 897                 .timeout        = &timeparms,
 898                 .program        = &cb_program,
 899                 .version        = 1,
 900                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 901                 .cred           = current_cred(),
 902         };
 903         struct rpc_clnt *client;
 904         const struct cred *cred;
 905
 906         if (clp->cl_minorversion == 0) {
 907                 if (!clp->cl_cred.cr_principal &&
 908                     (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
 909                         trace_nfsd_cb_setup_err(clp, -EINVAL);
 910                         return -EINVAL;
 911                 }
 912                 args.client_name = clp->cl_cred.cr_principal;
 913                 args.prognumber = conn->cb_prog;
 914                 args.protocol = XPRT_TRANSPORT_TCP;
 915                 args.authflavor = clp->cl_cred.cr_flavor;
 916                 clp->cl_cb_ident = conn->cb_ident;
 917         } else {
 918                 if (!conn->cb_xprt) {
 919                         trace_nfsd_cb_setup_err(clp, -EINVAL);
 920                         return -EINVAL;
 921                 }
 922                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 923                 clp->cl_cb_session = ses;
 924                 args.bc_xprt = conn->cb_xprt;
 925                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 926                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 927                                 XPRT_TRANSPORT_BC;
 928                 args.authflavor = ses->se_cb_sec.flavor;
 929         }
 930         /* Create RPC client */
 931         client = rpc_create(&args);
 932         if (IS_ERR(client)) {
 933                 trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
 934                 return PTR_ERR(client);
 935         }
 936         cred = get_backchannel_cred(clp, client, ses);
 937         if (!cred) {
 938                 trace_nfsd_cb_setup_err(clp, -ENOMEM);
 939                 rpc_shutdown_client(client);
 940                 return -ENOMEM;
 941         }
 942         clp->cl_cb_client = client;
 943         clp->cl_cb_cred = cred;
 944         trace_nfsd_cb_setup(clp);
 945         return 0;
 946 }
 947
 948 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 949 {
 950         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 951                 return;
 952         clp->cl_cb_state = NFSD4_CB_DOWN;
 953         trace_nfsd_cb_state(clp);
 954 }
 955
 956 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 957 {
 958         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
 959                 return;
 960         clp->cl_cb_state = NFSD4_CB_FAULT;
 961         trace_nfsd_cb_state(clp);
 962 }
 963
 964 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 965 {
 966         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 967
 968         trace_nfsd_cb_done(clp, task->tk_status);
 969         if (task->tk_status)
 970                 nfsd4_mark_cb_down(clp, task->tk_status);
 971         else {
 972                 clp->cl_cb_state = NFSD4_CB_UP;
 973                 trace_nfsd_cb_state(clp);
 974         }
 975 }
 976
 977 static void nfsd4_cb_probe_release(void *calldata)
 978 {
 979         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 980
 981         nfsd41_cb_inflight_end(clp);
 982
 983 }
 984
 985 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 986         /* XXX: release method to ensure we set the cb channel down if
 987          * necessary on early failure? */
 988         .rpc_call_done = nfsd4_cb_probe_done,
 989         .rpc_release = nfsd4_cb_probe_release,
 990 };
 991
 992 /*
 993  * Poke the callback thread to process any updates to the callback
 994  * parameters, and send a null probe.
 995  */
 996 void nfsd4_probe_callback(struct nfs4_client *clp)
 997 {
 998         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 999         trace_nfsd_cb_state(clp);
1000         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1001         nfsd4_run_cb(&clp->cl_cb_null);
1002 }
1003
1004 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
1005 {
1006         nfsd4_probe_callback(clp);
1007         flush_workqueue(callback_wq);
1008 }
1009
1010 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
1011 {
1012         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
1013         spin_lock(&clp->cl_lock);
1014         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
1015         spin_unlock(&clp->cl_lock);
1016         trace_nfsd_cb_state(clp);
1017 }
1018
1019 /*
1020  * There's currently a single callback channel slot.
1021  * If the slot is available, then mark it busy.  Otherwise, set the
1022  * thread for sleeping on the callback RPC wait queue.
1023  */
1024 static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
1025 {
1026         struct nfs4_client *clp = cb->cb_clp;
1027
1028         if (!cb->cb_holds_slot &&
1029             test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1030                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1031                 /* Race breaker */
1032                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1033                         dprintk("%s slot is busy\n", __func__);
1034                         return false;
1035                 }
1036                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1037         }
1038         cb->cb_holds_slot = true;
1039         return true;
1040 }
1041
1042 static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
1043 {
1044         struct nfs4_client *clp = cb->cb_clp;
1045
1046         if (cb->cb_holds_slot) {
1047                 cb->cb_holds_slot = false;
1048                 clear_bit(0, &clp->cl_cb_slot_busy);
1049                 rpc_wake_up_next(&clp->cl_cb_waitq);
1050         }
1051 }
1052
1053 static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
1054 {
1055         struct nfs4_client *clp = cb->cb_clp;
1056
1057         nfsd41_cb_release_slot(cb);
1058         if (cb->cb_ops && cb->cb_ops->release)
1059                 cb->cb_ops->release(cb);
1060         nfsd41_cb_inflight_end(clp);
1061 }
1062
1063 /*
1064  * TODO: cb_sequence should support referring call lists, cachethis, multiple
1065  * slots, and mark callback channel down on communication errors.
1066  */
1067 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1068 {
1069         struct nfsd4_callback *cb = calldata;
1070         struct nfs4_client *clp = cb->cb_clp;
1071         u32 minorversion = clp->cl_minorversion;
1072
1073         /*
1074          * cb_seq_status is only set in decode_cb_sequence4res,
1075          * and so will remain 1 if an rpc level failure occurs.
1076          */
1077         cb->cb_seq_status = 1;
1078         cb->cb_status = 0;
1079         if (minorversion && !nfsd41_cb_get_slot(cb, task))
1080                 return;
1081         rpc_call_start(task);
1082 }
1083
1084 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1085 {
1086         struct nfs4_client *clp = cb->cb_clp;
1087         struct nfsd4_session *session = clp->cl_cb_session;
1088         bool ret = true;
1089
1090         if (!clp->cl_minorversion) {
1091                 /*
1092                  * If the backchannel connection was shut down while this
1093                  * task was queued, we need to resubmit it after setting up
1094                  * a new backchannel connection.
1095                  *
1096                  * Note that if we lost our callback connection permanently
1097                  * the submission code will error out, so we don't need to
1098                  * handle that case here.
1099                  */
1100                 if (RPC_SIGNALLED(task))
1101                         goto need_restart;
1102
1103                 return true;
1104         }
1105
1106         if (!cb->cb_holds_slot)
1107                 goto need_restart;
1108
1109         switch (cb->cb_seq_status) {
1110         case 0:
1111                 /*
1112                  * No need for lock, access serialized in nfsd4_cb_prepare
1113                  *
1114                  * RFC5661 20.9.3
1115                  * If CB_SEQUENCE returns an error, then the state of the slot
1116                  * (sequence ID, cached reply) MUST NOT change.
1117                  */
1118                 ++session->se_cb_seq_nr;
1119                 break;
1120         case -ESERVERFAULT:
1121                 ++session->se_cb_seq_nr;
1122                 fallthrough;
1123         case 1:
1124         case -NFS4ERR_BADSESSION:
1125                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1126                 ret = false;
1127                 break;
1128         case -NFS4ERR_DELAY:
1129                 if (!rpc_restart_call(task))
1130                         goto out;
1131
1132                 rpc_delay(task, 2 * HZ);
1133                 return false;
1134         case -NFS4ERR_BADSLOT:
1135                 goto retry_nowait;
1136         case -NFS4ERR_SEQ_MISORDERED:
1137                 if (session->se_cb_seq_nr != 1) {
1138                         session->se_cb_seq_nr = 1;
1139                         goto retry_nowait;
1140                 }
1141                 break;
1142         default:
1143                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1144                 dprintk("%s: unprocessed error %d\n", __func__,
1145                         cb->cb_seq_status);
1146         }
1147
1148         nfsd41_cb_release_slot(cb);
1149         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1150                 clp->cl_cb_session->se_cb_seq_nr);
1151
1152         if (RPC_SIGNALLED(task))
1153                 goto need_restart;
1154 out:
1155         return ret;
1156 retry_nowait:
1157         if (rpc_restart_call_prepare(task))
1158                 ret = false;
1159         goto out;
1160 need_restart:
1161         if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
1162                 task->tk_status = 0;
1163                 cb->cb_need_restart = true;
1164         }
1165         return false;
1166 }
1167
1168 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1169 {
1170         struct nfsd4_callback *cb = calldata;
1171         struct nfs4_client *clp = cb->cb_clp;
1172
1173         trace_nfsd_cb_done(clp, task->tk_status);
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                         nfsd4_mark_cb_down(clp, task->tk_status);
1193                 }
1194                 break;
1195         default:
1196                 BUG();
1197         }
1198 }
1199
1200 static void nfsd4_cb_release(void *calldata)
1201 {
1202         struct nfsd4_callback *cb = calldata;
1203
1204         if (cb->cb_need_restart)
1205                 nfsd4_queue_cb(cb);
1206         else
1207                 nfsd41_destroy_cb(cb);
1208
1209 }
1210
1211 static const struct rpc_call_ops nfsd4_cb_ops = {
1212         .rpc_call_prepare = nfsd4_cb_prepare,
1213         .rpc_call_done = nfsd4_cb_done,
1214         .rpc_release = nfsd4_cb_release,
1215 };
1216
1217 int nfsd4_create_callback_queue(void)
1218 {
1219         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1220         if (!callback_wq)
1221                 return -ENOMEM;
1222         return 0;
1223 }
1224
1225 void nfsd4_destroy_callback_queue(void)
1226 {
1227         destroy_workqueue(callback_wq);
1228 }
1229
1230 /* must be called under the state lock */
1231 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1232 {
1233         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1234         /*
1235          * Note this won't actually result in a null callback;
1236          * instead, nfsd4_run_cb_null() will detect the killed
1237          * client, destroy the rpc client, and stop:
1238          */
1239         nfsd4_run_cb(&clp->cl_cb_null);
1240         flush_workqueue(callback_wq);
1241         nfsd41_cb_inflight_wait_complete(clp);
1242 }
1243
1244 /* requires cl_lock: */
1245 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1246 {
1247         struct nfsd4_session *s;
1248         struct nfsd4_conn *c;
1249
1250         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1251                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1252                         if (c->cn_flags & NFS4_CDFC4_BACK)
1253                                 return c;
1254                 }
1255         }
1256         return NULL;
1257 }
1258
1259 /*
1260  * Note there isn't a lot of locking in this code; instead we depend on
1261  * the fact that it is run from the callback_wq, which won't run two
1262  * work items at once.  So, for example, callback_wq handles all access
1263  * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
1264  */
1265 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1266 {
1267         struct nfs4_cb_conn conn;
1268         struct nfs4_client *clp = cb->cb_clp;
1269         struct nfsd4_session *ses = NULL;
1270         struct nfsd4_conn *c;
1271         int err;
1272
1273         /*
1274          * This is either an update, or the client dying; in either case,
1275          * kill the old client:
1276          */
1277         if (clp->cl_cb_client) {
1278                 trace_nfsd_cb_shutdown(clp);
1279                 rpc_shutdown_client(clp->cl_cb_client);
1280                 clp->cl_cb_client = NULL;
1281                 put_cred(clp->cl_cb_cred);
1282                 clp->cl_cb_cred = NULL;
1283         }
1284         if (clp->cl_cb_conn.cb_xprt) {
1285                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1286                 clp->cl_cb_conn.cb_xprt = NULL;
1287         }
1288         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1289                 return;
1290         spin_lock(&clp->cl_lock);
1291         /*
1292          * Only serialized callback code is allowed to clear these
1293          * flags; main nfsd code can only set them:
1294          */
1295         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1296         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1297         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1298         c = __nfsd4_find_backchannel(clp);
1299         if (c) {
1300                 svc_xprt_get(c->cn_xprt);
1301                 conn.cb_xprt = c->cn_xprt;
1302                 ses = c->cn_session;
1303         }
1304         spin_unlock(&clp->cl_lock);
1305
1306         err = setup_callback_client(clp, &conn, ses);
1307         if (err) {
1308                 nfsd4_mark_cb_down(clp, err);
1309                 if (c)
1310                         svc_xprt_put(c->cn_xprt);
1311                 return;
1312         }
1313 }
1314
1315 static void
1316 nfsd4_run_cb_work(struct work_struct *work)
1317 {
1318         struct nfsd4_callback *cb =
1319                 container_of(work, struct nfsd4_callback, cb_work);
1320         struct nfs4_client *clp = cb->cb_clp;
1321         struct rpc_clnt *clnt;
1322         int flags;
1323
1324         trace_nfsd_cb_work(clp, cb->cb_msg.rpc_proc->p_name);
1325
1326         if (cb->cb_need_restart) {
1327                 cb->cb_need_restart = false;
1328         } else {
1329                 if (cb->cb_ops && cb->cb_ops->prepare)
1330                         cb->cb_ops->prepare(cb);
1331         }
1332
1333         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1334                 nfsd4_process_cb_update(cb);
1335
1336         clnt = clp->cl_cb_client;
1337         if (!clnt) {
1338                 /* Callback channel broken, or client killed; give up: */
1339                 nfsd41_destroy_cb(cb);
1340                 return;
1341         }
1342
1343         /*
1344          * Don't send probe messages for 4.1 or later.
1345          */
1346         if (!cb->cb_ops && clp->cl_minorversion) {
1347                 clp->cl_cb_state = NFSD4_CB_UP;
1348                 nfsd41_destroy_cb(cb);
1349                 return;
1350         }
1351
1352         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1353         flags = clp->cl_minorversion ? RPC_TASK_NOCONNECT : RPC_TASK_SOFTCONN;
1354         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | flags,
1355                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1356 }
1357
1358 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1359                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1360 {
1361         cb->cb_clp = clp;
1362         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1363         cb->cb_msg.rpc_argp = cb;
1364         cb->cb_msg.rpc_resp = cb;
1365         cb->cb_ops = ops;
1366         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1367         cb->cb_seq_status = 1;
1368         cb->cb_status = 0;
1369         cb->cb_need_restart = false;
1370         cb->cb_holds_slot = false;
1371 }
1372
1373 void nfsd4_run_cb(struct nfsd4_callback *cb)
1374 {
1375         struct nfs4_client *clp = cb->cb_clp;
1376
1377         nfsd41_cb_inflight_begin(clp);
1378         if (!nfsd4_queue_cb(cb))
1379                 nfsd41_cb_inflight_end(clp);
1380 }