fs/nfsd/nfs4callback.c

   1 /*
   2  *  Copyright (c) 2001 The Regents of the University of Michigan.
   3  *  All rights reserved.
   4  *
   5  *  Kendrick Smith <kmsmith@umich.edu>
   6  *  Andy Adamson <andros@umich.edu>
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions
  10  *  are met:
  11  *
  12  *  1. Redistributions of source code must retain the above copyright
  13  *     notice, this list of conditions and the following disclaimer.
  14  *  2. Redistributions in binary form must reproduce the above copyright
  15  *     notice, this list of conditions and the following disclaimer in the
  16  *     documentation and/or other materials provided with the distribution.
  17  *  3. Neither the name of the University nor the names of its
  18  *     contributors may be used to endorse or promote products derived
  19  *     from this software without specific prior written permission.
  20  *
  21  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  22  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  24  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  29  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  30  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  31  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/xprt.h>
  36 #include <linux/sunrpc/svc_xprt.h>
  37 #include <linux/slab.h>
  38 #include "nfsd.h"
  39 #include "state.h"
  40 #include "netns.h"
  41 #include "xdr4cb.h"
  42
  43 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  44
  45 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
  46
  47 #define NFSPROC4_CB_NULL 0
  48 #define NFSPROC4_CB_COMPOUND 1
  49
  50 /* Index of predefined Linux callback client operations */
  51
  52 struct nfs4_cb_compound_hdr {
  53         /* args */
  54         u32             ident;  /* minorversion 0 only */
  55         u32             nops;
  56         __be32          *nops_p;
  57         u32             minorversion;
  58         /* res */
  59         int             status;
  60 };
  61
  62 /*
  63  * Handle decode buffer overflows out-of-line.
  64  */
  65 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
  66 {
  67         dprintk("NFS: %s prematurely hit the end of our receive buffer. "
  68                 "Remaining buffer length is %tu words.\n",
  69                 func, xdr->end - xdr->p);
  70 }
  71
  72 static __be32 *xdr_encode_empty_array(__be32 *p)
  73 {
  74         *p++ = xdr_zero;
  75         return p;
  76 }
  77
  78 /*
  79  * Encode/decode NFSv4 CB basic data types
  80  *
  81  * Basic NFSv4 callback data types are defined in section 15 of RFC
  82  * 3530: "Network File System (NFS) version 4 Protocol" and section
  83  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
  84  * 1 Protocol"
  85  */
  86
  87 /*
  88  *      nfs_cb_opnum4
  89  *
  90  *      enum nfs_cb_opnum4 {
  91  *              OP_CB_GETATTR           = 3,
  92  *                ...
  93  *      };
  94  */
  95 enum nfs_cb_opnum4 {
  96         OP_CB_GETATTR                   = 3,
  97         OP_CB_RECALL                    = 4,
  98         OP_CB_LAYOUTRECALL              = 5,
  99         OP_CB_NOTIFY                    = 6,
 100         OP_CB_PUSH_DELEG                = 7,
 101         OP_CB_RECALL_ANY                = 8,
 102         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 103         OP_CB_RECALL_SLOT               = 10,
 104         OP_CB_SEQUENCE                  = 11,
 105         OP_CB_WANTS_CANCELLED           = 12,
 106         OP_CB_NOTIFY_LOCK               = 13,
 107         OP_CB_NOTIFY_DEVICEID           = 14,
 108         OP_CB_ILLEGAL                   = 10044
 109 };
 110
 111 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 112 {
 113         __be32 *p;
 114
 115         p = xdr_reserve_space(xdr, 4);
 116         *p = cpu_to_be32(op);
 117 }
 118
 119 /*
 120  * nfs_fh4
 121  *
 122  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 123  */
 124 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 125 {
 126         u32 length = fh->fh_size;
 127         __be32 *p;
 128
 129         BUG_ON(length > NFS4_FHSIZE);
 130         p = xdr_reserve_space(xdr, 4 + length);
 131         xdr_encode_opaque(p, &fh->fh_base, length);
 132 }
 133
 134 /*
 135  * stateid4
 136  *
 137  *      struct stateid4 {
 138  *              uint32_t        seqid;
 139  *              opaque          other[12];
 140  *      };
 141  */
 142 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 143 {
 144         __be32 *p;
 145
 146         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 147         *p++ = cpu_to_be32(sid->si_generation);
 148         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 149 }
 150
 151 /*
 152  * sessionid4
 153  *
 154  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 155  */
 156 static void encode_sessionid4(struct xdr_stream *xdr,
 157                               const struct nfsd4_session *session)
 158 {
 159         __be32 *p;
 160
 161         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 162         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 163                                         NFS4_MAX_SESSIONID_LEN);
 164 }
 165
 166 /*
 167  * nfsstat4
 168  */
 169 static const struct {
 170         int stat;
 171         int errno;
 172 } nfs_cb_errtbl[] = {
 173         { NFS4_OK,              0               },
 174         { NFS4ERR_PERM,         -EPERM          },
 175         { NFS4ERR_NOENT,        -ENOENT         },
 176         { NFS4ERR_IO,           -EIO            },
 177         { NFS4ERR_NXIO,         -ENXIO          },
 178         { NFS4ERR_ACCESS,       -EACCES         },
 179         { NFS4ERR_EXIST,        -EEXIST         },
 180         { NFS4ERR_XDEV,         -EXDEV          },
 181         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 182         { NFS4ERR_ISDIR,        -EISDIR         },
 183         { NFS4ERR_INVAL,        -EINVAL         },
 184         { NFS4ERR_FBIG,         -EFBIG          },
 185         { NFS4ERR_NOSPC,        -ENOSPC         },
 186         { NFS4ERR_ROFS,         -EROFS          },
 187         { NFS4ERR_MLINK,        -EMLINK         },
 188         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 189         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 190         { NFS4ERR_DQUOT,        -EDQUOT         },
 191         { NFS4ERR_STALE,        -ESTALE         },
 192         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 193         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 194         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 195         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 196         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 197         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 198         { NFS4ERR_LOCKED,       -EAGAIN         },
 199         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 200         { NFS4ERR_SYMLINK,      -ELOOP          },
 201         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 202         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 203         { -1,                   -EIO            }
 204 };
 205
 206 /*
 207  * If we cannot translate the error, the recovery routines should
 208  * handle it.
 209  *
 210  * Note: remaining NFSv4 error codes have values > 10000, so should
 211  * not conflict with native Linux error codes.
 212  */
 213 static int nfs_cb_stat_to_errno(int status)
 214 {
 215         int i;
 216
 217         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 218                 if (nfs_cb_errtbl[i].stat == status)
 219                         return nfs_cb_errtbl[i].errno;
 220         }
 221
 222         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 223         return -status;
 224 }
 225
 226 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
 227                                int *status)
 228 {
 229         __be32 *p;
 230         u32 op;
 231
 232         p = xdr_inline_decode(xdr, 4 + 4);
 233         if (unlikely(p == NULL))
 234                 goto out_overflow;
 235         op = be32_to_cpup(p++);
 236         if (unlikely(op != expected))
 237                 goto out_unexpected;
 238         *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 239         return 0;
 240 out_overflow:
 241         print_overflow_msg(__func__, xdr);
 242         return -EIO;
 243 out_unexpected:
 244         dprintk("NFSD: Callback server returned operation %d but "
 245                 "we issued a request for %d\n", op, expected);
 246         return -EIO;
 247 }
 248
 249 /*
 250  * CB_COMPOUND4args
 251  *
 252  *      struct CB_COMPOUND4args {
 253  *              utf8str_cs      tag;
 254  *              uint32_t        minorversion;
 255  *              uint32_t        callback_ident;
 256  *              nfs_cb_argop4   argarray<>;
 257  *      };
 258 */
 259 static void encode_cb_compound4args(struct xdr_stream *xdr,
 260                                     struct nfs4_cb_compound_hdr *hdr)
 261 {
 262         __be32 * p;
 263
 264         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 265         p = xdr_encode_empty_array(p);          /* empty tag */
 266         *p++ = cpu_to_be32(hdr->minorversion);
 267         *p++ = cpu_to_be32(hdr->ident);
 268
 269         hdr->nops_p = p;
 270         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 271 }
 272
 273 /*
 274  * Update argarray element count
 275  */
 276 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 277 {
 278         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 279         *hdr->nops_p = cpu_to_be32(hdr->nops);
 280 }
 281
 282 /*
 283  * CB_COMPOUND4res
 284  *
 285  *      struct CB_COMPOUND4res {
 286  *              nfsstat4        status;
 287  *              utf8str_cs      tag;
 288  *              nfs_cb_resop4   resarray<>;
 289  *      };
 290  */
 291 static int decode_cb_compound4res(struct xdr_stream *xdr,
 292                                   struct nfs4_cb_compound_hdr *hdr)
 293 {
 294         u32 length;
 295         __be32 *p;
 296
 297         p = xdr_inline_decode(xdr, 4 + 4);
 298         if (unlikely(p == NULL))
 299                 goto out_overflow;
 300         hdr->status = be32_to_cpup(p++);
 301         /* Ignore the tag */
 302         length = be32_to_cpup(p++);
 303         p = xdr_inline_decode(xdr, length + 4);
 304         if (unlikely(p == NULL))
 305                 goto out_overflow;
 306         hdr->nops = be32_to_cpup(p);
 307         return 0;
 308 out_overflow:
 309         print_overflow_msg(__func__, xdr);
 310         return -EIO;
 311 }
 312
 313 /*
 314  * CB_RECALL4args
 315  *
 316  *      struct CB_RECALL4args {
 317  *              stateid4        stateid;
 318  *              bool            truncate;
 319  *              nfs_fh4         fh;
 320  *      };
 321  */
 322 static void encode_cb_recall4args(struct xdr_stream *xdr,
 323                                   const struct nfs4_delegation *dp,
 324                                   struct nfs4_cb_compound_hdr *hdr)
 325 {
 326         __be32 *p;
 327
 328         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 329         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 330
 331         p = xdr_reserve_space(xdr, 4);
 332         *p++ = xdr_zero;                        /* truncate */
 333
 334         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 335
 336         hdr->nops++;
 337 }
 338
 339 /*
 340  * CB_SEQUENCE4args
 341  *
 342  *      struct CB_SEQUENCE4args {
 343  *              sessionid4              csa_sessionid;
 344  *              sequenceid4             csa_sequenceid;
 345  *              slotid4                 csa_slotid;
 346  *              slotid4                 csa_highest_slotid;
 347  *              bool                    csa_cachethis;
 348  *              referring_call_list4    csa_referring_call_lists<>;
 349  *      };
 350  */
 351 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 352                                     const struct nfsd4_callback *cb,
 353                                     struct nfs4_cb_compound_hdr *hdr)
 354 {
 355         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 356         __be32 *p;
 357
 358         if (hdr->minorversion == 0)
 359                 return;
 360
 361         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 362         encode_sessionid4(xdr, session);
 363
 364         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 365         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 366         *p++ = xdr_zero;                        /* csa_slotid */
 367         *p++ = xdr_zero;                        /* csa_highest_slotid */
 368         *p++ = xdr_zero;                        /* csa_cachethis */
 369         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 370
 371         hdr->nops++;
 372 }
 373
 374 /*
 375  * CB_SEQUENCE4resok
 376  *
 377  *      struct CB_SEQUENCE4resok {
 378  *              sessionid4      csr_sessionid;
 379  *              sequenceid4     csr_sequenceid;
 380  *              slotid4         csr_slotid;
 381  *              slotid4         csr_highest_slotid;
 382  *              slotid4         csr_target_highest_slotid;
 383  *      };
 384  *
 385  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 386  *      case NFS4_OK:
 387  *              CB_SEQUENCE4resok       csr_resok4;
 388  *      default:
 389  *              void;
 390  *      };
 391  *
 392  * Our current back channel implmentation supports a single backchannel
 393  * with a single slot.
 394  */
 395 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 396                                     struct nfsd4_callback *cb)
 397 {
 398         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 399         struct nfs4_sessionid id;
 400         int status;
 401         __be32 *p;
 402         u32 dummy;
 403
 404         status = -ESERVERFAULT;
 405
 406         /*
 407          * If the server returns different values for sessionID, slotID or
 408          * sequence number, the server is looney tunes.
 409          */
 410         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 411         if (unlikely(p == NULL))
 412                 goto out_overflow;
 413         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 414         if (memcmp(id.data, session->se_sessionid.data,
 415                                         NFS4_MAX_SESSIONID_LEN) != 0) {
 416                 dprintk("NFS: %s Invalid session id\n", __func__);
 417                 goto out;
 418         }
 419         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 420
 421         dummy = be32_to_cpup(p++);
 422         if (dummy != session->se_cb_seq_nr) {
 423                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 424                 goto out;
 425         }
 426
 427         dummy = be32_to_cpup(p++);
 428         if (dummy != 0) {
 429                 dprintk("NFS: %s Invalid slotid\n", __func__);
 430                 goto out;
 431         }
 432
 433         /*
 434          * FIXME: process highest slotid and target highest slotid
 435          */
 436         status = 0;
 437 out:
 438         cb->cb_seq_status = status;
 439         return status;
 440 out_overflow:
 441         print_overflow_msg(__func__, xdr);
 442         status = -EIO;
 443         goto out;
 444 }
 445
 446 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 447                                   struct nfsd4_callback *cb)
 448 {
 449         int status;
 450
 451         if (cb->cb_minorversion == 0)
 452                 return 0;
 453
 454         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 455         if (unlikely(status || cb->cb_seq_status))
 456                 return status;
 457
 458         return decode_cb_sequence4resok(xdr, cb);
 459 }
 460
 461 /*
 462  * NFSv4.0 and NFSv4.1 XDR encode functions
 463  *
 464  * NFSv4.0 callback argument types are defined in section 15 of RFC
 465  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 466  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 467  * Protocol".
 468  */
 469
 470 /*
 471  * NB: Without this zero space reservation, callbacks over krb5p fail
 472  */
 473 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 474                                  void *__unused)
 475 {
 476         xdr_reserve_space(xdr, 0);
 477 }
 478
 479 /*
 480  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 481  */
 482 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 483                                    const struct nfsd4_callback *cb)
 484 {
 485         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 486         struct nfs4_cb_compound_hdr hdr = {
 487                 .ident = cb->cb_clp->cl_cb_ident,
 488                 .minorversion = cb->cb_minorversion,
 489         };
 490
 491         encode_cb_compound4args(xdr, &hdr);
 492         encode_cb_sequence4args(xdr, cb, &hdr);
 493         encode_cb_recall4args(xdr, dp, &hdr);
 494         encode_cb_nops(&hdr);
 495 }
 496
 497
 498 /*
 499  * NFSv4.0 and NFSv4.1 XDR decode functions
 500  *
 501  * NFSv4.0 callback result types are defined in section 15 of RFC
 502  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 503  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 504  * Protocol".
 505  */
 506
 507 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 508                                 void *__unused)
 509 {
 510         return 0;
 511 }
 512
 513 /*
 514  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 515  */
 516 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 517                                   struct xdr_stream *xdr,
 518                                   struct nfsd4_callback *cb)
 519 {
 520         struct nfs4_cb_compound_hdr hdr;
 521         int status;
 522
 523         status = decode_cb_compound4res(xdr, &hdr);
 524         if (unlikely(status))
 525                 return status;
 526
 527         if (cb != NULL) {
 528                 status = decode_cb_sequence4res(xdr, cb);
 529                 if (unlikely(status || cb->cb_seq_status))
 530                         return status;
 531         }
 532
 533         return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 534 }
 535
 536 #ifdef CONFIG_NFSD_PNFS
 537 /*
 538  * CB_LAYOUTRECALL4args
 539  *
 540  *      struct layoutrecall_file4 {
 541  *              nfs_fh4         lor_fh;
 542  *              offset4         lor_offset;
 543  *              length4         lor_length;
 544  *              stateid4        lor_stateid;
 545  *      };
 546  *
 547  *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 548  *      case LAYOUTRECALL4_FILE:
 549  *              layoutrecall_file4 lor_layout;
 550  *      case LAYOUTRECALL4_FSID:
 551  *              fsid4              lor_fsid;
 552  *      case LAYOUTRECALL4_ALL:
 553  *              void;
 554  *      };
 555  *
 556  *      struct CB_LAYOUTRECALL4args {
 557  *              layouttype4             clora_type;
 558  *              layoutiomode4           clora_iomode;
 559  *              bool                    clora_changed;
 560  *              layoutrecall4           clora_recall;
 561  *      };
 562  */
 563 static void encode_cb_layout4args(struct xdr_stream *xdr,
 564                                   const struct nfs4_layout_stateid *ls,
 565                                   struct nfs4_cb_compound_hdr *hdr)
 566 {
 567         __be32 *p;
 568
 569         BUG_ON(hdr->minorversion == 0);
 570
 571         p = xdr_reserve_space(xdr, 5 * 4);
 572         *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 573         *p++ = cpu_to_be32(ls->ls_layout_type);
 574         *p++ = cpu_to_be32(IOMODE_ANY);
 575         *p++ = cpu_to_be32(1);
 576         *p = cpu_to_be32(RETURN_FILE);
 577
 578         encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 579
 580         p = xdr_reserve_space(xdr, 2 * 8);
 581         p = xdr_encode_hyper(p, 0);
 582         xdr_encode_hyper(p, NFS4_MAX_UINT64);
 583
 584         encode_stateid4(xdr, &ls->ls_recall_sid);
 585
 586         hdr->nops++;
 587 }
 588
 589 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 590                                    struct xdr_stream *xdr,
 591                                    const struct nfsd4_callback *cb)
 592 {
 593         const struct nfs4_layout_stateid *ls =
 594                 container_of(cb, struct nfs4_layout_stateid, ls_recall);
 595         struct nfs4_cb_compound_hdr hdr = {
 596                 .ident = 0,
 597                 .minorversion = cb->cb_minorversion,
 598         };
 599
 600         encode_cb_compound4args(xdr, &hdr);
 601         encode_cb_sequence4args(xdr, cb, &hdr);
 602         encode_cb_layout4args(xdr, ls, &hdr);
 603         encode_cb_nops(&hdr);
 604 }
 605
 606 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 607                                   struct xdr_stream *xdr,
 608                                   struct nfsd4_callback *cb)
 609 {
 610         struct nfs4_cb_compound_hdr hdr;
 611         int status;
 612
 613         status = decode_cb_compound4res(xdr, &hdr);
 614         if (unlikely(status))
 615                 return status;
 616
 617         if (cb) {
 618                 status = decode_cb_sequence4res(xdr, cb);
 619                 if (unlikely(status || cb->cb_seq_status))
 620                         return status;
 621         }
 622         return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 623 }
 624 #endif /* CONFIG_NFSD_PNFS */
 625
 626 /*
 627  * RPC procedure tables
 628  */
 629 #define PROC(proc, call, argtype, restype)                              \
 630 [NFSPROC4_CLNT_##proc] = {                                              \
 631         .p_proc    = NFSPROC4_CB_##call,                                \
 632         .p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,               \
 633         .p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,               \
 634         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 635         .p_replen  = NFS4_dec_##restype##_sz,                           \
 636         .p_statidx = NFSPROC4_CB_##call,                                \
 637         .p_name    = #proc,                                             \
 638 }
 639
 640 static struct rpc_procinfo nfs4_cb_procedures[] = {
 641         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 642         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 643 #ifdef CONFIG_NFSD_PNFS
 644         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 645 #endif
 646 };
 647
 648 static struct rpc_version nfs_cb_version4 = {
 649 /*
 650  * Note on the callback rpc program version number: despite language in rfc
 651  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 652  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 653  * in practice that appears to be what implementations use.  The section
 654  * 18.36.3 language is expected to be fixed in an erratum.
 655  */
 656         .number                 = 1,
 657         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 658         .procs                  = nfs4_cb_procedures
 659 };
 660
 661 static const struct rpc_version *nfs_cb_version[] = {
 662         &nfs_cb_version4,
 663 };
 664
 665 static const struct rpc_program cb_program;
 666
 667 static struct rpc_stat cb_stats = {
 668         .program                = &cb_program
 669 };
 670
 671 #define NFS4_CALLBACK 0x40000000
 672 static const struct rpc_program cb_program = {
 673         .name                   = "nfs4_cb",
 674         .number                 = NFS4_CALLBACK,
 675         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 676         .version                = nfs_cb_version,
 677         .stats                  = &cb_stats,
 678         .pipe_dir_name          = "nfsd4_cb",
 679 };
 680
 681 static int max_cb_time(struct net *net)
 682 {
 683         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 684         return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
 685 }
 686
 687 static struct rpc_cred *callback_cred;
 688
 689 int set_callback_cred(void)
 690 {
 691         if (callback_cred)
 692                 return 0;
 693         callback_cred = rpc_lookup_machine_cred("nfs");
 694         if (!callback_cred)
 695                 return -ENOMEM;
 696         return 0;
 697 }
 698
 699 void cleanup_callback_cred(void)
 700 {
 701         if (callback_cred) {
 702                 put_rpccred(callback_cred);
 703                 callback_cred = NULL;
 704         }
 705 }
 706
 707 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
 708 {
 709         if (clp->cl_minorversion == 0) {
 710                 return get_rpccred(callback_cred);
 711         } else {
 712                 struct rpc_auth *auth = client->cl_auth;
 713                 struct auth_cred acred = {};
 714
 715                 acred.uid = ses->se_cb_sec.uid;
 716                 acred.gid = ses->se_cb_sec.gid;
 717                 return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
 718         }
 719 }
 720
 721 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 722 {
 723         int maxtime = max_cb_time(clp->net);
 724         struct rpc_timeout      timeparms = {
 725                 .to_initval     = maxtime,
 726                 .to_retries     = 0,
 727                 .to_maxval      = maxtime,
 728         };
 729         struct rpc_create_args args = {
 730                 .net            = clp->net,
 731                 .address        = (struct sockaddr *) &conn->cb_addr,
 732                 .addrsize       = conn->cb_addrlen,
 733                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 734                 .timeout        = &timeparms,
 735                 .program        = &cb_program,
 736                 .version        = 0,
 737                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 738         };
 739         struct rpc_clnt *client;
 740         struct rpc_cred *cred;
 741
 742         if (clp->cl_minorversion == 0) {
 743                 if (!clp->cl_cred.cr_principal &&
 744                                 (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
 745                         return -EINVAL;
 746                 args.client_name = clp->cl_cred.cr_principal;
 747                 args.prognumber = conn->cb_prog;
 748                 args.protocol = XPRT_TRANSPORT_TCP;
 749                 args.authflavor = clp->cl_cred.cr_flavor;
 750                 clp->cl_cb_ident = conn->cb_ident;
 751         } else {
 752                 if (!conn->cb_xprt)
 753                         return -EINVAL;
 754                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 755                 clp->cl_cb_session = ses;
 756                 args.bc_xprt = conn->cb_xprt;
 757                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 758                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
 759                                 XPRT_TRANSPORT_BC;
 760                 args.authflavor = ses->se_cb_sec.flavor;
 761         }
 762         /* Create RPC client */
 763         client = rpc_create(&args);
 764         if (IS_ERR(client)) {
 765                 dprintk("NFSD: couldn't create callback client: %ld\n",
 766                         PTR_ERR(client));
 767                 return PTR_ERR(client);
 768         }
 769         cred = get_backchannel_cred(clp, client, ses);
 770         if (IS_ERR(cred)) {
 771                 rpc_shutdown_client(client);
 772                 return PTR_ERR(cred);
 773         }
 774         clp->cl_cb_client = client;
 775         clp->cl_cb_cred = cred;
 776         return 0;
 777 }
 778
 779 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 780 {
 781         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 782                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 783 }
 784
 785 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 786 {
 787         clp->cl_cb_state = NFSD4_CB_DOWN;
 788         warn_no_callback_path(clp, reason);
 789 }
 790
 791 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
 792 {
 793         clp->cl_cb_state = NFSD4_CB_FAULT;
 794         warn_no_callback_path(clp, reason);
 795 }
 796
 797 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 798 {
 799         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 800
 801         if (task->tk_status)
 802                 nfsd4_mark_cb_down(clp, task->tk_status);
 803         else
 804                 clp->cl_cb_state = NFSD4_CB_UP;
 805 }
 806
 807 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 808         /* XXX: release method to ensure we set the cb channel down if
 809          * necessary on early failure? */
 810         .rpc_call_done = nfsd4_cb_probe_done,
 811 };
 812
 813 static struct workqueue_struct *callback_wq;
 814
 815 /*
 816  * Poke the callback thread to process any updates to the callback
 817  * parameters, and send a null probe.
 818  */
 819 void nfsd4_probe_callback(struct nfs4_client *clp)
 820 {
 821         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 822         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
 823         nfsd4_run_cb(&clp->cl_cb_null);
 824 }
 825
 826 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 827 {
 828         nfsd4_probe_callback(clp);
 829         flush_workqueue(callback_wq);
 830 }
 831
 832 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 833 {
 834         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 835         spin_lock(&clp->cl_lock);
 836         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 837         spin_unlock(&clp->cl_lock);
 838 }
 839
 840 /*
 841  * There's currently a single callback channel slot.
 842  * If the slot is available, then mark it busy.  Otherwise, set the
 843  * thread for sleeping on the callback RPC wait queue.
 844  */
 845 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 846 {
 847         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 848                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 849                 /* Race breaker */
 850                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 851                         dprintk("%s slot is busy\n", __func__);
 852                         return false;
 853                 }
 854                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
 855         }
 856         return true;
 857 }
 858
 859 /*
 860  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 861  * slots, and mark callback channel down on communication errors.
 862  */
 863 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 864 {
 865         struct nfsd4_callback *cb = calldata;
 866         struct nfs4_client *clp = cb->cb_clp;
 867         u32 minorversion = clp->cl_minorversion;
 868
 869         cb->cb_minorversion = minorversion;
 870         /*
 871          * cb_seq_status is only set in decode_cb_sequence4res,
 872          * and so will remain 1 if an rpc level failure occurs.
 873          */
 874         cb->cb_seq_status = 1;
 875         cb->cb_status = 0;
 876         if (minorversion) {
 877                 if (!cb->cb_holds_slot && !nfsd41_cb_get_slot(clp, task))
 878                         return;
 879                 cb->cb_holds_slot = true;
 880         }
 881         rpc_call_start(task);
 882 }
 883
 884 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
 885 {
 886         struct nfs4_client *clp = cb->cb_clp;
 887         struct nfsd4_session *session = clp->cl_cb_session;
 888         bool ret = true;
 889
 890         if (!clp->cl_minorversion) {
 891                 /*
 892                  * If the backchannel connection was shut down while this
 893                  * task was queued, we need to resubmit it after setting up
 894                  * a new backchannel connection.
 895                  *
 896                  * Note that if we lost our callback connection permanently
 897                  * the submission code will error out, so we don't need to
 898                  * handle that case here.
 899                  */
 900                 if (task->tk_flags & RPC_TASK_KILLED)
 901                         goto need_restart;
 902
 903                 return true;
 904         }
 905
 906         if (!cb->cb_holds_slot)
 907                 goto need_restart;
 908
 909         switch (cb->cb_seq_status) {
 910         case 0:
 911                 /*
 912                  * No need for lock, access serialized in nfsd4_cb_prepare
 913                  *
 914                  * RFC5661 20.9.3
 915                  * If CB_SEQUENCE returns an error, then the state of the slot
 916                  * (sequence ID, cached reply) MUST NOT change.
 917                  */
 918                 ++session->se_cb_seq_nr;
 919                 break;
 920         case -ESERVERFAULT:
 921                 ++session->se_cb_seq_nr;
 922         case 1:
 923         case -NFS4ERR_BADSESSION:
 924                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
 925                 ret = false;
 926                 break;
 927         case -NFS4ERR_DELAY:
 928                 if (!rpc_restart_call(task))
 929                         goto out;
 930
 931                 rpc_delay(task, 2 * HZ);
 932                 return false;
 933         case -NFS4ERR_BADSLOT:
 934                 goto retry_nowait;
 935         case -NFS4ERR_SEQ_MISORDERED:
 936                 if (session->se_cb_seq_nr != 1) {
 937                         session->se_cb_seq_nr = 1;
 938                         goto retry_nowait;
 939                 }
 940                 break;
 941         default:
 942                 dprintk("%s: unprocessed error %d\n", __func__,
 943                         cb->cb_seq_status);
 944         }
 945
 946         cb->cb_holds_slot = false;
 947         clear_bit(0, &clp->cl_cb_slot_busy);
 948         rpc_wake_up_next(&clp->cl_cb_waitq);
 949         dprintk("%s: freed slot, new seqid=%d\n", __func__,
 950                 clp->cl_cb_session->se_cb_seq_nr);
 951
 952         if (task->tk_flags & RPC_TASK_KILLED)
 953                 goto need_restart;
 954 out:
 955         return ret;
 956 retry_nowait:
 957         if (rpc_restart_call_prepare(task))
 958                 ret = false;
 959         goto out;
 960 need_restart:
 961         task->tk_status = 0;
 962         cb->cb_need_restart = true;
 963         return false;
 964 }
 965
 966 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 967 {
 968         struct nfsd4_callback *cb = calldata;
 969         struct nfs4_client *clp = cb->cb_clp;
 970
 971         dprintk("%s: minorversion=%d\n", __func__,
 972                 clp->cl_minorversion);
 973
 974         if (!nfsd4_cb_sequence_done(task, cb))
 975                 return;
 976
 977         if (cb->cb_status) {
 978                 WARN_ON_ONCE(task->tk_status);
 979                 task->tk_status = cb->cb_status;
 980         }
 981
 982         switch (cb->cb_ops->done(cb, task)) {
 983         case 0:
 984                 task->tk_status = 0;
 985                 rpc_restart_call_prepare(task);
 986                 return;
 987         case 1:
 988                 break;
 989         case -1:
 990                 /* Network partition? */
 991                 nfsd4_mark_cb_down(clp, task->tk_status);
 992                 break;
 993         default:
 994                 BUG();
 995         }
 996 }
 997
 998 static void nfsd4_cb_release(void *calldata)
 999 {
1000         struct nfsd4_callback *cb = calldata;
1001
1002         if (cb->cb_need_restart)
1003                 nfsd4_run_cb(cb);
1004         else
1005                 cb->cb_ops->release(cb);
1006
1007 }
1008
1009 static const struct rpc_call_ops nfsd4_cb_ops = {
1010         .rpc_call_prepare = nfsd4_cb_prepare,
1011         .rpc_call_done = nfsd4_cb_done,
1012         .rpc_release = nfsd4_cb_release,
1013 };
1014
1015 int nfsd4_create_callback_queue(void)
1016 {
1017         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
1018         if (!callback_wq)
1019                 return -ENOMEM;
1020         return 0;
1021 }
1022
1023 void nfsd4_destroy_callback_queue(void)
1024 {
1025         destroy_workqueue(callback_wq);
1026 }
1027
1028 /* must be called under the state lock */
1029 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1030 {
1031         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1032         /*
1033          * Note this won't actually result in a null callback;
1034          * instead, nfsd4_run_cb_null() will detect the killed
1035          * client, destroy the rpc client, and stop:
1036          */
1037         nfsd4_run_cb(&clp->cl_cb_null);
1038         flush_workqueue(callback_wq);
1039 }
1040
1041 /* requires cl_lock: */
1042 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1043 {
1044         struct nfsd4_session *s;
1045         struct nfsd4_conn *c;
1046
1047         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1048                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1049                         if (c->cn_flags & NFS4_CDFC4_BACK)
1050                                 return c;
1051                 }
1052         }
1053         return NULL;
1054 }
1055
1056 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1057 {
1058         struct nfs4_cb_conn conn;
1059         struct nfs4_client *clp = cb->cb_clp;
1060         struct nfsd4_session *ses = NULL;
1061         struct nfsd4_conn *c;
1062         int err;
1063
1064         /*
1065          * This is either an update, or the client dying; in either case,
1066          * kill the old client:
1067          */
1068         if (clp->cl_cb_client) {
1069                 rpc_shutdown_client(clp->cl_cb_client);
1070                 clp->cl_cb_client = NULL;
1071                 put_rpccred(clp->cl_cb_cred);
1072                 clp->cl_cb_cred = NULL;
1073         }
1074         if (clp->cl_cb_conn.cb_xprt) {
1075                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1076                 clp->cl_cb_conn.cb_xprt = NULL;
1077         }
1078         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1079                 return;
1080         spin_lock(&clp->cl_lock);
1081         /*
1082          * Only serialized callback code is allowed to clear these
1083          * flags; main nfsd code can only set them:
1084          */
1085         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1086         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1087         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1088         c = __nfsd4_find_backchannel(clp);
1089         if (c) {
1090                 svc_xprt_get(c->cn_xprt);
1091                 conn.cb_xprt = c->cn_xprt;
1092                 ses = c->cn_session;
1093         }
1094         spin_unlock(&clp->cl_lock);
1095
1096         err = setup_callback_client(clp, &conn, ses);
1097         if (err) {
1098                 nfsd4_mark_cb_down(clp, err);
1099                 if (c)
1100                         svc_xprt_put(c->cn_xprt);
1101                 return;
1102         }
1103 }
1104
1105 static void
1106 nfsd4_run_cb_work(struct work_struct *work)
1107 {
1108         struct nfsd4_callback *cb =
1109                 container_of(work, struct nfsd4_callback, cb_work);
1110         struct nfs4_client *clp = cb->cb_clp;
1111         struct rpc_clnt *clnt;
1112
1113         if (cb->cb_need_restart) {
1114                 cb->cb_need_restart = false;
1115         } else {
1116                 if (cb->cb_ops && cb->cb_ops->prepare)
1117                         cb->cb_ops->prepare(cb);
1118         }
1119
1120         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1121                 nfsd4_process_cb_update(cb);
1122
1123         clnt = clp->cl_cb_client;
1124         if (!clnt) {
1125                 /* Callback channel broken, or client killed; give up: */
1126                 if (cb->cb_ops && cb->cb_ops->release)
1127                         cb->cb_ops->release(cb);
1128                 return;
1129         }
1130
1131         /*
1132          * Don't send probe messages for 4.1 or later.
1133          */
1134         if (!cb->cb_ops && clp->cl_minorversion) {
1135                 clp->cl_cb_state = NFSD4_CB_UP;
1136                 return;
1137         }
1138
1139         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1140         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1141                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1142 }
1143
1144 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1145                 struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1146 {
1147         cb->cb_clp = clp;
1148         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1149         cb->cb_msg.rpc_argp = cb;
1150         cb->cb_msg.rpc_resp = cb;
1151         cb->cb_ops = ops;
1152         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1153         cb->cb_seq_status = 1;
1154         cb->cb_status = 0;
1155         cb->cb_need_restart = false;
1156         cb->cb_holds_slot = false;
1157 }
1158
1159 void nfsd4_run_cb(struct nfsd4_callback *cb)
1160 {
1161         queue_work(callback_wq, &cb->cb_work);
1162 }