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 static void encode_uint32(struct xdr_stream *xdr, u32 n)
  80 {
  81         WARN_ON_ONCE(xdr_stream_encode_u32(xdr, n) < 0);
  82 }
  83
  84 static void encode_bitmap4(struct xdr_stream *xdr, const __u32 *bitmap,
  85                            size_t len)
  86 {
  87         WARN_ON_ONCE(xdr_stream_encode_uint32_array(xdr, bitmap, len) < 0);
  88 }
  89
  90 /*
  91  *      nfs_cb_opnum4
  92  *
  93  *      enum nfs_cb_opnum4 {
  94  *              OP_CB_GETATTR           = 3,
  95  *                ...
  96  *      };
  97  */
  98 enum nfs_cb_opnum4 {
  99         OP_CB_GETATTR                   = 3,
 100         OP_CB_RECALL                    = 4,
 101         OP_CB_LAYOUTRECALL              = 5,
 102         OP_CB_NOTIFY                    = 6,
 103         OP_CB_PUSH_DELEG                = 7,
 104         OP_CB_RECALL_ANY                = 8,
 105         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 106         OP_CB_RECALL_SLOT               = 10,
 107         OP_CB_SEQUENCE                  = 11,
 108         OP_CB_WANTS_CANCELLED           = 12,
 109         OP_CB_NOTIFY_LOCK               = 13,
 110         OP_CB_NOTIFY_DEVICEID           = 14,
 111         OP_CB_OFFLOAD                   = 15,
 112         OP_CB_ILLEGAL                   = 10044
 113 };
 114
 115 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 116 {
 117         __be32 *p;
 118
 119         p = xdr_reserve_space(xdr, 4);
 120         *p = cpu_to_be32(op);
 121 }
 122
 123 /*
 124  * nfs_fh4
 125  *
 126  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 127  */
 128 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 129 {
 130         u32 length = fh->fh_size;
 131         __be32 *p;
 132
 133         BUG_ON(length > NFS4_FHSIZE);
 134         p = xdr_reserve_space(xdr, 4 + length);
 135         xdr_encode_opaque(p, &fh->fh_raw, length);
 136 }
 137
 138 /*
 139  * stateid4
 140  *
 141  *      struct stateid4 {
 142  *              uint32_t        seqid;
 143  *              opaque          other[12];
 144  *      };
 145  */
 146 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 147 {
 148         __be32 *p;
 149
 150         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 151         *p++ = cpu_to_be32(sid->si_generation);
 152         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 153 }
 154
 155 /*
 156  * sessionid4
 157  *
 158  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 159  */
 160 static void encode_sessionid4(struct xdr_stream *xdr,
 161                               const struct nfsd4_session *session)
 162 {
 163         __be32 *p;
 164
 165         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 166         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 167                                         NFS4_MAX_SESSIONID_LEN);
 168 }
 169
 170 /*
 171  * nfsstat4
 172  */
 173 static const struct {
 174         int stat;
 175         int errno;
 176 } nfs_cb_errtbl[] = {
 177         { NFS4_OK,              0               },
 178         { NFS4ERR_PERM,         -EPERM          },
 179         { NFS4ERR_NOENT,        -ENOENT         },
 180         { NFS4ERR_IO,           -EIO            },
 181         { NFS4ERR_NXIO,         -ENXIO          },
 182         { NFS4ERR_ACCESS,       -EACCES         },
 183         { NFS4ERR_EXIST,        -EEXIST         },
 184         { NFS4ERR_XDEV,         -EXDEV          },
 185         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 186         { NFS4ERR_ISDIR,        -EISDIR         },
 187         { NFS4ERR_INVAL,        -EINVAL         },
 188         { NFS4ERR_FBIG,         -EFBIG          },
 189         { NFS4ERR_NOSPC,        -ENOSPC         },
 190         { NFS4ERR_ROFS,         -EROFS          },
 191         { NFS4ERR_MLINK,        -EMLINK         },
 192         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 193         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 194         { NFS4ERR_DQUOT,        -EDQUOT         },
 195         { NFS4ERR_STALE,        -ESTALE         },
 196         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 197         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 198         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 199         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 200         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 201         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 202         { NFS4ERR_LOCKED,       -EAGAIN         },
 203         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 204         { NFS4ERR_SYMLINK,      -ELOOP          },
 205         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 206         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 207         { -1,                   -EIO            }
 208 };
 209
 210 /*
 211  * If we cannot translate the error, the recovery routines should
 212  * handle it.
 213  *
 214  * Note: remaining NFSv4 error codes have values > 10000, so should
 215  * not conflict with native Linux error codes.
 216  */
 217 static int nfs_cb_stat_to_errno(int status)
 218 {
 219         int i;
 220
 221         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 222                 if (nfs_cb_errtbl[i].stat == status)
 223                         return nfs_cb_errtbl[i].errno;
 224         }
 225
 226         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 227         return -status;
 228 }
 229
 230 static int decode_cb_op_status(struct xdr_stream *xdr,
 231                                enum nfs_cb_opnum4 expected, int *status)
 232 {
 233         __be32 *p;
 234         u32 op;
 235
 236         p = xdr_inline_decode(xdr, 4 + 4);
 237         if (unlikely(p == NULL))
 238                 goto out_overflow;
 239         op = be32_to_cpup(p++);
 240         if (unlikely(op != expected))
 241                 goto out_unexpected;
 242         *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 243         return 0;
 244 out_overflow:
 245         return -EIO;
 246 out_unexpected:
 247         dprintk("NFSD: Callback server returned operation %d but "
 248                 "we issued a request for %d\n", op, expected);
 249         return -EIO;
 250 }
 251
 252 /*
 253  * CB_COMPOUND4args
 254  *
 255  *      struct CB_COMPOUND4args {
 256  *              utf8str_cs      tag;
 257  *              uint32_t        minorversion;
 258  *              uint32_t        callback_ident;
 259  *              nfs_cb_argop4   argarray<>;
 260  *      };
 261 */
 262 static void encode_cb_compound4args(struct xdr_stream *xdr,
 263                                     struct nfs4_cb_compound_hdr *hdr)
 264 {
 265         __be32 * p;
 266
 267         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 268         p = xdr_encode_empty_array(p);          /* empty tag */
 269         *p++ = cpu_to_be32(hdr->minorversion);
 270         *p++ = cpu_to_be32(hdr->ident);
 271
 272         hdr->nops_p = p;
 273         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 274 }
 275
 276 /*
 277  * Update argarray element count
 278  */
 279 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 280 {
 281         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 282         *hdr->nops_p = cpu_to_be32(hdr->nops);
 283 }
 284
 285 /*
 286  * CB_COMPOUND4res
 287  *
 288  *      struct CB_COMPOUND4res {
 289  *              nfsstat4        status;
 290  *              utf8str_cs      tag;
 291  *              nfs_cb_resop4   resarray<>;
 292  *      };
 293  */
 294 static int decode_cb_compound4res(struct xdr_stream *xdr,
 295                                   struct nfs4_cb_compound_hdr *hdr)
 296 {
 297         u32 length;
 298         __be32 *p;
 299
 300         p = xdr_inline_decode(xdr, 4 + 4);
 301         if (unlikely(p == NULL))
 302                 goto out_overflow;
 303         hdr->status = be32_to_cpup(p++);
 304         /* Ignore the tag */
 305         length = be32_to_cpup(p++);
 306         p = xdr_inline_decode(xdr, length + 4);
 307         if (unlikely(p == NULL))
 308                 goto out_overflow;
 309         p += XDR_QUADLEN(length);
 310         hdr->nops = be32_to_cpup(p);
 311         return 0;
 312 out_overflow:
 313         return -EIO;
 314 }
 315
 316 /*
 317  * CB_RECALL4args
 318  *
 319  *      struct CB_RECALL4args {
 320  *              stateid4        stateid;
 321  *              bool            truncate;
 322  *              nfs_fh4         fh;
 323  *      };
 324  */
 325 static void encode_cb_recall4args(struct xdr_stream *xdr,
 326                                   const struct nfs4_delegation *dp,
 327                                   struct nfs4_cb_compound_hdr *hdr)
 328 {
 329         __be32 *p;
 330
 331         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 332         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 333
 334         p = xdr_reserve_space(xdr, 4);
 335         *p++ = xdr_zero;                        /* truncate */
 336
 337         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 338
 339         hdr->nops++;
 340 }
 341
 342 /*
 343  * CB_RECALLANY4args
 344  *
 345  *      struct CB_RECALLANY4args {
 346  *              uint32_t        craa_objects_to_keep;
 347  *              bitmap4         craa_type_mask;
 348  *      };
 349  */
 350 static void
 351 encode_cb_recallany4args(struct xdr_stream *xdr,
 352         struct nfs4_cb_compound_hdr *hdr, struct nfsd4_cb_recall_any *ra)
 353 {
 354         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL_ANY);
 355         encode_uint32(xdr, ra->ra_keep);
 356         encode_bitmap4(xdr, ra->ra_bmval, ARRAY_SIZE(ra->ra_bmval));
 357         hdr->nops++;
 358 }
 359
 360 /*
 361  * CB_SEQUENCE4args
 362  *
 363  *      struct CB_SEQUENCE4args {
 364  *              sessionid4              csa_sessionid;
 365  *              sequenceid4             csa_sequenceid;
 366  *              slotid4                 csa_slotid;
 367  *              slotid4                 csa_highest_slotid;
 368  *              bool                    csa_cachethis;
 369  *              referring_call_list4    csa_referring_call_lists<>;
 370  *      };
 371  */
 372 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 373                                     const struct nfsd4_callback *cb,
 374                                     struct nfs4_cb_compound_hdr *hdr)
 375 {
 376         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 377         __be32 *p;
 378
 379         if (hdr->minorversion == 0)
 380                 return;
 381
 382         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 383         encode_sessionid4(xdr, session);
 384
 385         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 386         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 387         *p++ = xdr_zero;                        /* csa_slotid */
 388         *p++ = xdr_zero;                        /* csa_highest_slotid */
 389         *p++ = xdr_zero;                        /* csa_cachethis */
 390         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 391
 392         hdr->nops++;
 393 }
 394
 395 /*
 396  * CB_SEQUENCE4resok
 397  *
 398  *      struct CB_SEQUENCE4resok {
 399  *              sessionid4      csr_sessionid;
 400  *              sequenceid4     csr_sequenceid;
 401  *              slotid4         csr_slotid;
 402  *              slotid4         csr_highest_slotid;
 403  *              slotid4         csr_target_highest_slotid;
 404  *      };
 405  *
 406  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 407  *      case NFS4_OK:
 408  *              CB_SEQUENCE4resok       csr_resok4;
 409  *      default:
 410  *              void;
 411  *      };
 412  *
 413  * Our current back channel implmentation supports a single backchannel
 414  * with a single slot.
 415  */
 416 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 417                                     struct nfsd4_callback *cb)
 418 {
 419         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 420         int status = -ESERVERFAULT;
 421         __be32 *p;
 422         u32 dummy;
 423
 424         /*
 425          * If the server returns different values for sessionID, slotID or
 426          * sequence number, the server is looney tunes.
 427          */
 428         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 429         if (unlikely(p == NULL))
 430                 goto out_overflow;
 431
 432         if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 433                 dprintk("NFS: %s Invalid session id\n", __func__);
 434                 goto out;
 435         }
 436         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 437
 438         dummy = be32_to_cpup(p++);
 439         if (dummy != session->se_cb_seq_nr) {
 440                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 441                 goto out;
 442         }
 443
 444         dummy = be32_to_cpup(p++);
 445         if (dummy != 0) {
 446                 dprintk("NFS: %s Invalid slotid\n", __func__);
 447                 goto out;
 448         }
 449
 450         /*
 451          * FIXME: process highest slotid and target highest slotid
 452          */
 453         status = 0;
 454 out:
 455         cb->cb_seq_status = status;
 456         return status;
 457 out_overflow:
 458         status = -EIO;
 459         goto out;
 460 }
 461
 462 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 463                                   struct nfsd4_callback *cb)
 464 {
 465         int status;
 466
 467         if (cb->cb_clp->cl_minorversion == 0)
 468                 return 0;
 469
 470         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 471         if (unlikely(status || cb->cb_seq_status))
 472                 return status;
 473
 474         return decode_cb_sequence4resok(xdr, cb);
 475 }
 476
 477 /*
 478  * NFSv4.0 and NFSv4.1 XDR encode functions
 479  *
 480  * NFSv4.0 callback argument types are defined in section 15 of RFC
 481  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 482  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 483  * Protocol".
 484  */
 485
 486 /*
 487  * NB: Without this zero space reservation, callbacks over krb5p fail
 488  */
 489 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 490                                  const void *__unused)
 491 {
 492         xdr_reserve_space(xdr, 0);
 493 }
 494
 495 /*
 496  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 497  */
 498 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 499                                    const void *data)
 500 {
 501         const struct nfsd4_callback *cb = data;
 502         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 503         struct nfs4_cb_compound_hdr hdr = {
 504                 .ident = cb->cb_clp->cl_cb_ident,
 505                 .minorversion = cb->cb_clp->cl_minorversion,
 506         };
 507
 508         encode_cb_compound4args(xdr, &hdr);
 509         encode_cb_sequence4args(xdr, cb, &hdr);
 510         encode_cb_recall4args(xdr, dp, &hdr);
 511         encode_cb_nops(&hdr);
 512 }
 513
 514 /*
 515  * 20.6. Operation 8: CB_RECALL_ANY - Keep Any N Recallable Objects
 516  */
 517 static void
 518 nfs4_xdr_enc_cb_recall_any(struct rpc_rqst *req,
 519                 struct xdr_stream *xdr, const void *data)
 520 {
 521         const struct nfsd4_callback *cb = data;
 522         struct nfsd4_cb_recall_any *ra;
 523         struct nfs4_cb_compound_hdr hdr = {
 524                 .ident = cb->cb_clp->cl_cb_ident,
 525                 .minorversion = cb->cb_clp->cl_minorversion,
 526         };
 527
 528         ra = container_of(cb, struct nfsd4_cb_recall_any, ra_cb);
 529         encode_cb_compound4args(xdr, &hdr);
 530         encode_cb_sequence4args(xdr, cb, &hdr);
 531         encode_cb_recallany4args(xdr, &hdr, ra);
 532         encode_cb_nops(&hdr);
 533 }
 534
 535 /*
 536  * NFSv4.0 and NFSv4.1 XDR decode functions
 537  *
 538  * NFSv4.0 callback result types are defined in section 15 of RFC
 539  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 540  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 541  * Protocol".
 542  */
 543
 544 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 545                                 void *__unused)
 546 {
 547         return 0;
 548 }
 549
 550 /*
 551  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 552  */
 553 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 554                                   struct xdr_stream *xdr,
 555                                   void *data)
 556 {
 557         struct nfsd4_callback *cb = data;
 558         struct nfs4_cb_compound_hdr hdr;
 559         int status;
 560
 561         status = decode_cb_compound4res(xdr, &hdr);
 562         if (unlikely(status))
 563                 return status;
 564
 565         status = decode_cb_sequence4res(xdr, cb);
 566         if (unlikely(status || cb->cb_seq_status))
 567                 return status;
 568
 569         return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 570 }
 571
 572 /*
 573  * 20.6. Operation 8: CB_RECALL_ANY - Keep Any N Recallable Objects
 574  */
 575 static int
 576 nfs4_xdr_dec_cb_recall_any(struct rpc_rqst *rqstp,
 577                                   struct xdr_stream *xdr,
 578                                   void *data)
 579 {
 580         struct nfsd4_callback *cb = data;
 581         struct nfs4_cb_compound_hdr hdr;
 582         int status;
 583
 584         status = decode_cb_compound4res(xdr, &hdr);
 585         if (unlikely(status))
 586                 return status;
 587         status = decode_cb_sequence4res(xdr, cb);
 588         if (unlikely(status || cb->cb_seq_status))
 589                 return status;
 590         status =  decode_cb_op_status(xdr, OP_CB_RECALL_ANY, &cb->cb_status);
 591         return status;
 592 }
 593
 594 #ifdef CONFIG_NFSD_PNFS
 595 /*
 596  * CB_LAYOUTRECALL4args
 597  *
 598  *      struct layoutrecall_file4 {
 599  *              nfs_fh4         lor_fh;
 600  *              offset4         lor_offset;
 601  *              length4         lor_length;
 602  *              stateid4        lor_stateid;
 603  *      };
 604  *
 605  *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 606  *      case LAYOUTRECALL4_FILE:
 607  *              layoutrecall_file4 lor_layout;
 608  *      case LAYOUTRECALL4_FSID:
 609  *              fsid4              lor_fsid;
 610  *      case LAYOUTRECALL4_ALL:
 611  *              void;
 612  *      };
 613  *
 614  *      struct CB_LAYOUTRECALL4args {
 615  *              layouttype4             clora_type;
 616  *              layoutiomode4           clora_iomode;
 617  *              bool                    clora_changed;
 618  *              layoutrecall4           clora_recall;
 619  *      };
 620  */
 621 static void encode_cb_layout4args(struct xdr_stream *xdr,
 622                                   const struct nfs4_layout_stateid *ls,
 623                                   struct nfs4_cb_compound_hdr *hdr)
 624 {
 625         __be32 *p;
 626
 627         BUG_ON(hdr->minorversion == 0);
 628
 629         p = xdr_reserve_space(xdr, 5 * 4);
 630         *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 631         *p++ = cpu_to_be32(ls->ls_layout_type);
 632         *p++ = cpu_to_be32(IOMODE_ANY);
 633         *p++ = cpu_to_be32(1);
 634         *p = cpu_to_be32(RETURN_FILE);
 635
 636         encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 637
 638         p = xdr_reserve_space(xdr, 2 * 8);
 639         p = xdr_encode_hyper(p, 0);
 640         xdr_encode_hyper(p, NFS4_MAX_UINT64);
 641
 642         encode_stateid4(xdr, &ls->ls_recall_sid);
 643
 644         hdr->nops++;
 645 }
 646
 647 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 648                                    struct xdr_stream *xdr,
 649                                    const void *data)
 650 {
 651         const struct nfsd4_callback *cb = data;
 652         const struct nfs4_layout_stateid *ls =
 653                 container_of(cb, struct nfs4_layout_stateid, ls_recall);
 654         struct nfs4_cb_compound_hdr hdr = {
 655                 .ident = 0,
 656                 .minorversion = cb->cb_clp->cl_minorversion,
 657         };
 658
 659         encode_cb_compound4args(xdr, &hdr);
 660         encode_cb_sequence4args(xdr, cb, &hdr);
 661         encode_cb_layout4args(xdr, ls, &hdr);
 662         encode_cb_nops(&hdr);
 663 }
 664
 665 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 666                                   struct xdr_stream *xdr,
 667                                   void *data)
 668 {
 669         struct nfsd4_callback *cb = data;
 670         struct nfs4_cb_compound_hdr hdr;
 671         int status;
 672
 673         status = decode_cb_compound4res(xdr, &hdr);
 674         if (unlikely(status))
 675                 return status;
 676
 677         status = decode_cb_sequence4res(xdr, cb);
 678         if (unlikely(status || cb->cb_seq_status))
 679                 return status;
 680
 681         return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 682 }
 683 #endif /* CONFIG_NFSD_PNFS */
 684
 685 static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
 686 {
 687         __be32  *p;
 688
 689         p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
 690         p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
 691         xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
 692 }
 693
 694 static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 695                                         struct xdr_stream *xdr,
 696                                         const void *data)
 697 {
 698         const struct nfsd4_callback *cb = data;
 699         const struct nfsd4_blocked_lock *nbl =
 700                 container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
 701         struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
 702         struct nfs4_cb_compound_hdr hdr = {
 703                 .ident = 0,
 704                 .minorversion = cb->cb_clp->cl_minorversion,
 705         };
 706
 707         __be32 *p;
 708
 709         BUG_ON(hdr.minorversion == 0);
 710
 711         encode_cb_compound4args(xdr, &hdr);
 712         encode_cb_sequence4args(xdr, cb, &hdr);
 713
 714         p = xdr_reserve_space(xdr, 4);
 715         *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
 716         encode_nfs_fh4(xdr, &nbl->nbl_fh);
 717         encode_stateowner(xdr, &lo->lo_owner);
 718         hdr.nops++;
 719
 720         encode_cb_nops(&hdr);
 721 }
 722
 723 static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
 724                                         struct xdr_stream *xdr,
 725                                         void *data)
 726 {
 727         struct nfsd4_callback *cb = data;
 728         struct nfs4_cb_compound_hdr hdr;
 729         int status;
 730
 731         status = decode_cb_compound4res(xdr, &hdr);
 732         if (unlikely(status))
 733                 return status;
 734
 735         status = decode_cb_sequence4res(xdr, cb);
 736         if (unlikely(status || cb->cb_seq_status))
 737                 return status;
 738
 739         return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
 740 }
 741
 742 /*
 743  * struct write_response4 {
 744  *      stateid4        wr_callback_id<1>;
 745  *      length4         wr_count;
 746  *      stable_how4     wr_committed;
 747  *      verifier4       wr_writeverf;
 748  * };
 749  * union offload_info4 switch (nfsstat4 coa_status) {
 750  *      case NFS4_OK:
 751  *              write_response4 coa_resok4;
 752  *      default:
 753  *              length4         coa_bytes_copied;
 754  * };
 755  * struct CB_OFFLOAD4args {
 756  *      nfs_fh4         coa_fh;
 757  *      stateid4        coa_stateid;
 758  *      offload_info4   coa_offload_info;
 759  * };
 760  */
 761 static void encode_offload_info4(struct xdr_stream *xdr,
 762                                  const struct nfsd4_cb_offload *cbo)
 763 {
 764         __be32 *p;
 765
 766         p = xdr_reserve_space(xdr, 4);
 767         *p = cbo->co_nfserr;
 768         switch (cbo->co_nfserr) {
 769         case nfs_ok:
 770                 p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
 771                 p = xdr_encode_empty_array(p);
 772                 p = xdr_encode_hyper(p, cbo->co_res.wr_bytes_written);
 773                 *p++ = cpu_to_be32(cbo->co_res.wr_stable_how);
 774                 p = xdr_encode_opaque_fixed(p, cbo->co_res.wr_verifier.data,
 775                                             NFS4_VERIFIER_SIZE);
 776                 break;
 777         default:
 778                 p = xdr_reserve_space(xdr, 8);
 779                 /* We always return success if bytes were written */
 780                 p = xdr_encode_hyper(p, 0);
 781         }
 782 }
 783
 784 static void encode_cb_offload4args(struct xdr_stream *xdr,
 785                                    const struct nfsd4_cb_offload *cbo,
 786                                    struct nfs4_cb_compound_hdr *hdr)
 787 {
 788         __be32 *p;
 789
 790         p = xdr_reserve_space(xdr, 4);
 791         *p = cpu_to_be32(OP_CB_OFFLOAD);
 792         encode_nfs_fh4(xdr, &cbo->co_fh);
 793         encode_stateid4(xdr, &cbo->co_res.cb_stateid);
 794         encode_offload_info4(xdr, cbo);
 795
 796         hdr->nops++;
 797 }
 798
 799 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 800                                     struct xdr_stream *xdr,
 801                                     const void *data)
 802 {
 803         const struct nfsd4_callback *cb = data;
 804         const struct nfsd4_cb_offload *cbo =
 805                 container_of(cb, struct nfsd4_cb_offload, co_cb);
 806         struct nfs4_cb_compound_hdr hdr = {
 807                 .ident = 0,
 808                 .minorversion = cb->cb_clp->cl_minorversion,
 809         };
 810
 811         encode_cb_compound4args(xdr, &hdr);
 812         encode_cb_sequence4args(xdr, cb, &hdr);
 813         encode_cb_offload4args(xdr, cbo, &hdr);
 814         encode_cb_nops(&hdr);
 815 }
 816
 817 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 818                                    struct xdr_stream *xdr,
 819                                    void *data)
 820 {
 821         struct nfsd4_callback *cb = data;
 822         struct nfs4_cb_compound_hdr hdr;
 823         int status;
 824
 825         status = decode_cb_compound4res(xdr, &hdr);
 826         if (unlikely(status))
 827                 return status;
 828
 829         status = decode_cb_sequence4res(xdr, cb);
 830         if (unlikely(status || cb->cb_seq_status))
 831                 return status;
 832
 833         return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 834 }
 835 /*
 836  * RPC procedure tables
 837  */
 838 #define PROC(proc, call, argtype, restype)                              \
 839 [NFSPROC4_CLNT_##proc] = {                                              \
 840         .p_proc    = NFSPROC4_CB_##call,                                \
 841         .p_encode  = nfs4_xdr_enc_##argtype,            \
 842         .p_decode  = nfs4_xdr_dec_##restype,                            \
 843         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 844         .p_replen  = NFS4_dec_##restype##_sz,                           \
 845         .p_statidx = NFSPROC4_CB_##call,                                \
 846         .p_name    = #proc,                                             \
 847 }
 848
 849 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 850         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 851         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 852 #ifdef CONFIG_NFSD_PNFS
 853         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 854 #endif
 855         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 856         PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 857         PROC(CB_RECALL_ANY,     COMPOUND,       cb_recall_any,  cb_recall_any),
 858 };
 859
 860 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 861 static const struct rpc_version nfs_cb_version4 = {
 862 /*
 863  * Note on the callback rpc program version number: despite language in rfc
 864  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 865  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 866  * in practice that appears to be what implementations use.  The section
 867  * 18.36.3 language is expected to be fixed in an erratum.
 868  */
 869         .number                 = 1,
 870         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 871         .procs                  = nfs4_cb_procedures,
 872         .counts                 = nfs4_cb_counts,
 873 };
 874
 875 static const struct rpc_version *nfs_cb_version[2] = {
 876         [1] = &nfs_cb_version4,
 877 };
 878
 879 static const struct rpc_program cb_program;
 880
 881 static struct rpc_stat cb_stats = {
 882         .program                = &cb_program
 883 };
 884
 885 #define NFS4_CALLBACK 0x40000000
 886 static const struct rpc_program cb_program = {
 887         .name                   = "nfs4_cb",
 888         .number                 = NFS4_CALLBACK,
 889         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 890         .version                = nfs_cb_version,
 891         .stats                  = &cb_stats,
 892         .pipe_dir_name          = "nfsd4_cb",
 893 };
 894
 895 static int max_cb_time(struct net *net)
 896 {
 897         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 898
 899         /*
 900          * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
 901          * so we can use 32-bit math on it. Warn if that assumption
 902          * ever stops being true.
 903          */
 904         if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
 905                 return 360 * HZ;
 906
 907         return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
 908 }
 909
 910 static struct workqueue_struct *callback_wq;
 911
 912 static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
 913 {
 914         return queue_work(callback_wq, &cb->cb_work);
 915 }
 916
 917 static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
 918 {
 919         atomic_inc(&clp->cl_cb_inflight);
 920 }
 921
 922 static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
 923 {
 924
 925         if (atomic_dec_and_test(&clp->cl_cb_inflight))
 926                 wake_up_var(&clp->cl_cb_inflight);
 927 }
 928
 929 static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
 930 {
 931         wait_var_event(&clp->cl_cb_inflight,
 932                         !atomic_read(&clp->cl_cb_inflight));
 933 }
 934
 935 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 936 {
 937         if (clp->cl_minorversion == 0) {
 938                 client->cl_principal = clp->cl_cred.cr_targ_princ ?
 939                         clp->cl_cred.cr_targ_princ : "nfs";
 940
 941                 return get_cred(rpc_machine_cred());
 942         } else {
 943                 struct cred *kcred;
 944
 945                 kcred = prepare_kernel_cred(NULL);
 946                 if (!kcred)
 947                         return NULL;
 948
 949                 kcred->uid = ses->se_cb_sec.uid;
 950                 kcred->gid = ses->se_cb_sec.gid;
 951                 return kcred;
 952         }
 953 }
 954
 955 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 956 {
 957         int maxtime = max_cb_time(clp->net);
 958         struct rpc_timeout      timeparms = {
 959                 .to_initval     = maxtime,
 960                 .to_retries     = 0,
 961                 .to_maxval      = maxtime,
 962         };
 963         struct rpc_create_args args = {
 964                 .net            = clp->net,
 965                 .address        = (struct sockaddr *) &conn->cb_addr,
 966                 .addrsize       = conn->cb_addrlen,
 967                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 968                 .timeout        = &timeparms,
 969                 .program        = &cb_program,
 970                 .version        = 1,
 971                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 972                 .cred           = current_cred(),
 973         };
 974         struct rpc_clnt *client;
 975         const struct cred *cred;
 976
 977         if (clp->cl_minorversion == 0) {
 978                 if (!clp->cl_cred.cr_principal &&
 979                     (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
 980                         trace_nfsd_cb_setup_err(clp, -EINVAL);
 981                         return -EINVAL;
 982                 }
 983                 args.client_name = clp->cl_cred.cr_principal;
 984                 args.prognumber = conn->cb_prog;
 985                 args.protocol = XPRT_TRANSPORT_TCP;
 986                 args.authflavor = clp->cl_cred.cr_flavor;
 987                 clp->cl_cb_ident = conn->cb_ident;
 988         } else {
 989                 if (!conn->cb_xprt)
 990                         return -EINVAL;
 991                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 992                 clp->cl_cb_session = ses;
 993                 args.bc_xprt = conn->cb_xprt;
 994                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 995                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 996                                 XPRT_TRANSPORT_BC;
 997                 args.authflavor = ses->se_cb_sec.flavor;
 998         }
 999         /* Create RPC client */
1000         client = rpc_create(&args);
1001         if (IS_ERR(client)) {
1002                 trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
1003                 return PTR_ERR(client);
1004         }
1005         cred = get_backchannel_cred(clp, client, ses);
1006         if (!cred) {
1007                 trace_nfsd_cb_setup_err(clp, -ENOMEM);
1008                 rpc_shutdown_client(client);
1009                 return -ENOMEM;
1010         }
1011         clp->cl_cb_client = client;
1012         clp->cl_cb_cred = cred;
1013         rcu_read_lock();
1014         trace_nfsd_cb_setup(clp, rpc_peeraddr2str(client, RPC_DISPLAY_NETID),
1015                             args.authflavor);
1016         rcu_read_unlock();
1017         return 0;
1018 }
1019
1020 static void nfsd4_mark_cb_state(struct nfs4_client *clp, int newstate)
1021 {
1022         if (clp->cl_cb_state != newstate) {
1023                 clp->cl_cb_state = newstate;
1024                 trace_nfsd_cb_state(clp);
1025         }
1026 }
1027
1028 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
1029 {
1030         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
1031                 return;
1032         nfsd4_mark_cb_state(clp, NFSD4_CB_DOWN);
1033 }
1034
1035 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
1036 {
1037         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
1038                 return;
1039         nfsd4_mark_cb_state(clp, NFSD4_CB_FAULT);
1040 }
1041
1042 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
1043 {
1044         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
1045
1046         if (task->tk_status)
1047                 nfsd4_mark_cb_down(clp, task->tk_status);
1048         else
1049                 nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1050 }
1051
1052 static void nfsd4_cb_probe_release(void *calldata)
1053 {
1054         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
1055
1056         nfsd41_cb_inflight_end(clp);
1057
1058 }
1059
1060 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
1061         /* XXX: release method to ensure we set the cb channel down if
1062          * necessary on early failure? */
1063         .rpc_call_done = nfsd4_cb_probe_done,
1064         .rpc_release = nfsd4_cb_probe_release,
1065 };
1066
1067 /*
1068  * Poke the callback thread to process any updates to the callback
1069  * parameters, and send a null probe.
1070  */
1071 void nfsd4_probe_callback(struct nfs4_client *clp)
1072 {
1073         trace_nfsd_cb_probe(clp);
1074         nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1075         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1076         nfsd4_run_cb(&clp->cl_cb_null);
1077 }
1078
1079 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
1080 {
1081         nfsd4_probe_callback(clp);
1082         flush_workqueue(callback_wq);
1083 }
1084
1085 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
1086 {
1087         nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1088         spin_lock(&clp->cl_lock);
1089         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
1090         spin_unlock(&clp->cl_lock);
1091 }
1092
1093 /*
1094  * There's currently a single callback channel slot.
1095  * If the slot is available, then mark it busy.  Otherwise, set the
1096  * thread for sleeping on the callback RPC wait queue.
1097  */
1098 static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
1099 {
1100         struct nfs4_client *clp = cb->cb_clp;
1101
1102         if (!cb->cb_holds_slot &&
1103             test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1104                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1105                 /* Race breaker */
1106                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1107                         dprintk("%s slot is busy\n", __func__);
1108                         return false;
1109                 }
1110                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1111         }
1112         cb->cb_holds_slot = true;
1113         return true;
1114 }
1115
1116 static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
1117 {
1118         struct nfs4_client *clp = cb->cb_clp;
1119
1120         if (cb->cb_holds_slot) {
1121                 cb->cb_holds_slot = false;
1122                 clear_bit(0, &clp->cl_cb_slot_busy);
1123                 rpc_wake_up_next(&clp->cl_cb_waitq);
1124         }
1125 }
1126
1127 static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
1128 {
1129         struct nfs4_client *clp = cb->cb_clp;
1130
1131         nfsd41_cb_release_slot(cb);
1132         if (cb->cb_ops && cb->cb_ops->release)
1133                 cb->cb_ops->release(cb);
1134         nfsd41_cb_inflight_end(clp);
1135 }
1136
1137 /*
1138  * TODO: cb_sequence should support referring call lists, cachethis, multiple
1139  * slots, and mark callback channel down on communication errors.
1140  */
1141 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1142 {
1143         struct nfsd4_callback *cb = calldata;
1144         struct nfs4_client *clp = cb->cb_clp;
1145         u32 minorversion = clp->cl_minorversion;
1146
1147         /*
1148          * cb_seq_status is only set in decode_cb_sequence4res,
1149          * and so will remain 1 if an rpc level failure occurs.
1150          */
1151         cb->cb_seq_status = 1;
1152         cb->cb_status = 0;
1153         if (minorversion && !nfsd41_cb_get_slot(cb, task))
1154                 return;
1155         rpc_call_start(task);
1156 }
1157
1158 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1159 {
1160         struct nfs4_client *clp = cb->cb_clp;
1161         struct nfsd4_session *session = clp->cl_cb_session;
1162         bool ret = true;
1163
1164         if (!clp->cl_minorversion) {
1165                 /*
1166                  * If the backchannel connection was shut down while this
1167                  * task was queued, we need to resubmit it after setting up
1168                  * a new backchannel connection.
1169                  *
1170                  * Note that if we lost our callback connection permanently
1171                  * the submission code will error out, so we don't need to
1172                  * handle that case here.
1173                  */
1174                 if (RPC_SIGNALLED(task))
1175                         goto need_restart;
1176
1177                 return true;
1178         }
1179
1180         if (!cb->cb_holds_slot)
1181                 goto need_restart;
1182
1183         switch (cb->cb_seq_status) {
1184         case 0:
1185                 /*
1186                  * No need for lock, access serialized in nfsd4_cb_prepare
1187                  *
1188                  * RFC5661 20.9.3
1189                  * If CB_SEQUENCE returns an error, then the state of the slot
1190                  * (sequence ID, cached reply) MUST NOT change.
1191                  */
1192                 ++session->se_cb_seq_nr;
1193                 break;
1194         case -ESERVERFAULT:
1195                 ++session->se_cb_seq_nr;
1196                 fallthrough;
1197         case 1:
1198         case -NFS4ERR_BADSESSION:
1199                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1200                 ret = false;
1201                 break;
1202         case -NFS4ERR_DELAY:
1203                 if (!rpc_restart_call(task))
1204                         goto out;
1205
1206                 rpc_delay(task, 2 * HZ);
1207                 return false;
1208         case -NFS4ERR_BADSLOT:
1209                 goto retry_nowait;
1210         case -NFS4ERR_SEQ_MISORDERED:
1211                 if (session->se_cb_seq_nr != 1) {
1212                         session->se_cb_seq_nr = 1;
1213                         goto retry_nowait;
1214                 }
1215                 break;
1216         default:
1217                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1218                 dprintk("%s: unprocessed error %d\n", __func__,
1219                         cb->cb_seq_status);
1220         }
1221
1222         nfsd41_cb_release_slot(cb);
1223         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1224                 clp->cl_cb_session->se_cb_seq_nr);
1225
1226         if (RPC_SIGNALLED(task))
1227                 goto need_restart;
1228 out:
1229         return ret;
1230 retry_nowait:
1231         if (rpc_restart_call_prepare(task))
1232                 ret = false;
1233         goto out;
1234 need_restart:
1235         if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
1236                 task->tk_status = 0;
1237                 cb->cb_need_restart = true;
1238         }
1239         return false;
1240 }
1241
1242 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1243 {
1244         struct nfsd4_callback *cb = calldata;
1245         struct nfs4_client *clp = cb->cb_clp;
1246
1247         if (!nfsd4_cb_sequence_done(task, cb))
1248                 return;
1249
1250         if (cb->cb_status) {
1251                 WARN_ON_ONCE(task->tk_status);
1252                 task->tk_status = cb->cb_status;
1253         }
1254
1255         switch (cb->cb_ops->done(cb, task)) {
1256         case 0:
1257                 task->tk_status = 0;
1258                 rpc_restart_call_prepare(task);
1259                 return;
1260         case 1:
1261                 switch (task->tk_status) {
1262                 case -EIO:
1263                 case -ETIMEDOUT:
1264                 case -EACCES:
1265                         nfsd4_mark_cb_down(clp, task->tk_status);
1266                 }
1267                 break;
1268         default:
1269                 BUG();
1270         }
1271 }
1272
1273 static void nfsd4_cb_release(void *calldata)
1274 {
1275         struct nfsd4_callback *cb = calldata;
1276
1277         if (cb->cb_need_restart)
1278                 nfsd4_queue_cb(cb);
1279         else
1280                 nfsd41_destroy_cb(cb);
1281
1282 }
1283
1284 static const struct rpc_call_ops nfsd4_cb_ops = {
1285         .rpc_call_prepare = nfsd4_cb_prepare,
1286         .rpc_call_done = nfsd4_cb_done,
1287         .rpc_release = nfsd4_cb_release,
1288 };
1289
1290 int nfsd4_create_callback_queue(void)
1291 {
1292         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1293         if (!callback_wq)
1294                 return -ENOMEM;
1295         return 0;
1296 }
1297
1298 void nfsd4_destroy_callback_queue(void)
1299 {
1300         destroy_workqueue(callback_wq);
1301 }
1302
1303 /* must be called under the state lock */
1304 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1305 {
1306         if (clp->cl_cb_state != NFSD4_CB_UNKNOWN)
1307                 trace_nfsd_cb_shutdown(clp);
1308
1309         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1310         /*
1311          * Note this won't actually result in a null callback;
1312          * instead, nfsd4_run_cb_null() will detect the killed
1313          * client, destroy the rpc client, and stop:
1314          */
1315         nfsd4_run_cb(&clp->cl_cb_null);
1316         flush_workqueue(callback_wq);
1317         nfsd41_cb_inflight_wait_complete(clp);
1318 }
1319
1320 /* requires cl_lock: */
1321 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1322 {
1323         struct nfsd4_session *s;
1324         struct nfsd4_conn *c;
1325
1326         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1327                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1328                         if (c->cn_flags & NFS4_CDFC4_BACK)
1329                                 return c;
1330                 }
1331         }
1332         return NULL;
1333 }
1334
1335 /*
1336  * Note there isn't a lot of locking in this code; instead we depend on
1337  * the fact that it is run from the callback_wq, which won't run two
1338  * work items at once.  So, for example, callback_wq handles all access
1339  * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
1340  */
1341 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1342 {
1343         struct nfs4_cb_conn conn;
1344         struct nfs4_client *clp = cb->cb_clp;
1345         struct nfsd4_session *ses = NULL;
1346         struct nfsd4_conn *c;
1347         int err;
1348
1349         /*
1350          * This is either an update, or the client dying; in either case,
1351          * kill the old client:
1352          */
1353         if (clp->cl_cb_client) {
1354                 rpc_shutdown_client(clp->cl_cb_client);
1355                 clp->cl_cb_client = NULL;
1356                 put_cred(clp->cl_cb_cred);
1357                 clp->cl_cb_cred = NULL;
1358         }
1359         if (clp->cl_cb_conn.cb_xprt) {
1360                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1361                 clp->cl_cb_conn.cb_xprt = NULL;
1362         }
1363         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1364                 return;
1365         spin_lock(&clp->cl_lock);
1366         /*
1367          * Only serialized callback code is allowed to clear these
1368          * flags; main nfsd code can only set them:
1369          */
1370         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1371         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1372         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1373         c = __nfsd4_find_backchannel(clp);
1374         if (c) {
1375                 svc_xprt_get(c->cn_xprt);
1376                 conn.cb_xprt = c->cn_xprt;
1377                 ses = c->cn_session;
1378         }
1379         spin_unlock(&clp->cl_lock);
1380
1381         err = setup_callback_client(clp, &conn, ses);
1382         if (err) {
1383                 nfsd4_mark_cb_down(clp, err);
1384                 if (c)
1385                         svc_xprt_put(c->cn_xprt);
1386                 return;
1387         }
1388 }
1389
1390 static void
1391 nfsd4_run_cb_work(struct work_struct *work)
1392 {
1393         struct nfsd4_callback *cb =
1394                 container_of(work, struct nfsd4_callback, cb_work);
1395         struct nfs4_client *clp = cb->cb_clp;
1396         struct rpc_clnt *clnt;
1397         int flags;
1398
1399         if (cb->cb_need_restart) {
1400                 cb->cb_need_restart = false;
1401         } else {
1402                 if (cb->cb_ops && cb->cb_ops->prepare)
1403                         cb->cb_ops->prepare(cb);
1404         }
1405
1406         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1407                 nfsd4_process_cb_update(cb);
1408
1409         clnt = clp->cl_cb_client;
1410         if (!clnt) {
1411                 /* Callback channel broken, or client killed; give up: */
1412                 nfsd41_destroy_cb(cb);
1413                 return;
1414         }
1415
1416         /*
1417          * Don't send probe messages for 4.1 or later.
1418          */
1419         if (!cb->cb_ops && clp->cl_minorversion) {
1420                 nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1421                 nfsd41_destroy_cb(cb);
1422                 return;
1423         }
1424
1425         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1426         flags = clp->cl_minorversion ? RPC_TASK_NOCONNECT : RPC_TASK_SOFTCONN;
1427         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | flags,
1428                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1429 }
1430
1431 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1432                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1433 {
1434         cb->cb_clp = clp;
1435         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1436         cb->cb_msg.rpc_argp = cb;
1437         cb->cb_msg.rpc_resp = cb;
1438         cb->cb_ops = ops;
1439         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1440         cb->cb_seq_status = 1;
1441         cb->cb_status = 0;
1442         cb->cb_need_restart = false;
1443         cb->cb_holds_slot = false;
1444 }
1445
1446 /**
1447  * nfsd4_run_cb - queue up a callback job to run
1448  * @cb: callback to queue
1449  *
1450  * Kick off a callback to do its thing. Returns false if it was already
1451  * on a queue, true otherwise.
1452  */
1453 bool nfsd4_run_cb(struct nfsd4_callback *cb)
1454 {
1455         struct nfs4_client *clp = cb->cb_clp;
1456         bool queued;
1457
1458         nfsd41_cb_inflight_begin(clp);
1459         queued = nfsd4_queue_cb(cb);
1460         if (!queued)
1461                 nfsd41_cb_inflight_end(clp);
1462         return queued;
1463 }