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         xdr_stream_encode_uint32_array(xdr, bitmap, len);
  88 }
  89
  90 static int decode_cb_fattr4(struct xdr_stream *xdr, uint32_t *bitmap,
  91                                 struct nfs4_cb_fattr *fattr)
  92 {
  93         fattr->ncf_cb_change = 0;
  94         fattr->ncf_cb_fsize = 0;
  95         if (bitmap[0] & FATTR4_WORD0_CHANGE)
  96                 if (xdr_stream_decode_u64(xdr, &fattr->ncf_cb_change) < 0)
  97                         return -NFSERR_BAD_XDR;
  98         if (bitmap[0] & FATTR4_WORD0_SIZE)
  99                 if (xdr_stream_decode_u64(xdr, &fattr->ncf_cb_fsize) < 0)
 100                         return -NFSERR_BAD_XDR;
 101         return 0;
 102 }
 103
 104 /*
 105  *      nfs_cb_opnum4
 106  *
 107  *      enum nfs_cb_opnum4 {
 108  *              OP_CB_GETATTR           = 3,
 109  *                ...
 110  *      };
 111  */
 112 enum nfs_cb_opnum4 {
 113         OP_CB_GETATTR                   = 3,
 114         OP_CB_RECALL                    = 4,
 115         OP_CB_LAYOUTRECALL              = 5,
 116         OP_CB_NOTIFY                    = 6,
 117         OP_CB_PUSH_DELEG                = 7,
 118         OP_CB_RECALL_ANY                = 8,
 119         OP_CB_RECALLABLE_OBJ_AVAIL      = 9,
 120         OP_CB_RECALL_SLOT               = 10,
 121         OP_CB_SEQUENCE                  = 11,
 122         OP_CB_WANTS_CANCELLED           = 12,
 123         OP_CB_NOTIFY_LOCK               = 13,
 124         OP_CB_NOTIFY_DEVICEID           = 14,
 125         OP_CB_OFFLOAD                   = 15,
 126         OP_CB_ILLEGAL                   = 10044
 127 };
 128
 129 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
 130 {
 131         __be32 *p;
 132
 133         p = xdr_reserve_space(xdr, 4);
 134         *p = cpu_to_be32(op);
 135 }
 136
 137 /*
 138  * nfs_fh4
 139  *
 140  *      typedef opaque nfs_fh4<NFS4_FHSIZE>;
 141  */
 142 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
 143 {
 144         u32 length = fh->fh_size;
 145         __be32 *p;
 146
 147         BUG_ON(length > NFS4_FHSIZE);
 148         p = xdr_reserve_space(xdr, 4 + length);
 149         xdr_encode_opaque(p, &fh->fh_raw, length);
 150 }
 151
 152 /*
 153  * stateid4
 154  *
 155  *      struct stateid4 {
 156  *              uint32_t        seqid;
 157  *              opaque          other[12];
 158  *      };
 159  */
 160 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
 161 {
 162         __be32 *p;
 163
 164         p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
 165         *p++ = cpu_to_be32(sid->si_generation);
 166         xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
 167 }
 168
 169 /*
 170  * sessionid4
 171  *
 172  *      typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
 173  */
 174 static void encode_sessionid4(struct xdr_stream *xdr,
 175                               const struct nfsd4_session *session)
 176 {
 177         __be32 *p;
 178
 179         p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
 180         xdr_encode_opaque_fixed(p, session->se_sessionid.data,
 181                                         NFS4_MAX_SESSIONID_LEN);
 182 }
 183
 184 /*
 185  * nfsstat4
 186  */
 187 static const struct {
 188         int stat;
 189         int errno;
 190 } nfs_cb_errtbl[] = {
 191         { NFS4_OK,              0               },
 192         { NFS4ERR_PERM,         -EPERM          },
 193         { NFS4ERR_NOENT,        -ENOENT         },
 194         { NFS4ERR_IO,           -EIO            },
 195         { NFS4ERR_NXIO,         -ENXIO          },
 196         { NFS4ERR_ACCESS,       -EACCES         },
 197         { NFS4ERR_EXIST,        -EEXIST         },
 198         { NFS4ERR_XDEV,         -EXDEV          },
 199         { NFS4ERR_NOTDIR,       -ENOTDIR        },
 200         { NFS4ERR_ISDIR,        -EISDIR         },
 201         { NFS4ERR_INVAL,        -EINVAL         },
 202         { NFS4ERR_FBIG,         -EFBIG          },
 203         { NFS4ERR_NOSPC,        -ENOSPC         },
 204         { NFS4ERR_ROFS,         -EROFS          },
 205         { NFS4ERR_MLINK,        -EMLINK         },
 206         { NFS4ERR_NAMETOOLONG,  -ENAMETOOLONG   },
 207         { NFS4ERR_NOTEMPTY,     -ENOTEMPTY      },
 208         { NFS4ERR_DQUOT,        -EDQUOT         },
 209         { NFS4ERR_STALE,        -ESTALE         },
 210         { NFS4ERR_BADHANDLE,    -EBADHANDLE     },
 211         { NFS4ERR_BAD_COOKIE,   -EBADCOOKIE     },
 212         { NFS4ERR_NOTSUPP,      -ENOTSUPP       },
 213         { NFS4ERR_TOOSMALL,     -ETOOSMALL      },
 214         { NFS4ERR_SERVERFAULT,  -ESERVERFAULT   },
 215         { NFS4ERR_BADTYPE,      -EBADTYPE       },
 216         { NFS4ERR_LOCKED,       -EAGAIN         },
 217         { NFS4ERR_RESOURCE,     -EREMOTEIO      },
 218         { NFS4ERR_SYMLINK,      -ELOOP          },
 219         { NFS4ERR_OP_ILLEGAL,   -EOPNOTSUPP     },
 220         { NFS4ERR_DEADLOCK,     -EDEADLK        },
 221         { -1,                   -EIO            }
 222 };
 223
 224 /*
 225  * If we cannot translate the error, the recovery routines should
 226  * handle it.
 227  *
 228  * Note: remaining NFSv4 error codes have values > 10000, so should
 229  * not conflict with native Linux error codes.
 230  */
 231 static int nfs_cb_stat_to_errno(int status)
 232 {
 233         int i;
 234
 235         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 236                 if (nfs_cb_errtbl[i].stat == status)
 237                         return nfs_cb_errtbl[i].errno;
 238         }
 239
 240         dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
 241         return -status;
 242 }
 243
 244 static int decode_cb_op_status(struct xdr_stream *xdr,
 245                                enum nfs_cb_opnum4 expected, int *status)
 246 {
 247         __be32 *p;
 248         u32 op;
 249
 250         p = xdr_inline_decode(xdr, 4 + 4);
 251         if (unlikely(p == NULL))
 252                 goto out_overflow;
 253         op = be32_to_cpup(p++);
 254         if (unlikely(op != expected))
 255                 goto out_unexpected;
 256         *status = nfs_cb_stat_to_errno(be32_to_cpup(p));
 257         return 0;
 258 out_overflow:
 259         return -EIO;
 260 out_unexpected:
 261         dprintk("NFSD: Callback server returned operation %d but "
 262                 "we issued a request for %d\n", op, expected);
 263         return -EIO;
 264 }
 265
 266 /*
 267  * CB_COMPOUND4args
 268  *
 269  *      struct CB_COMPOUND4args {
 270  *              utf8str_cs      tag;
 271  *              uint32_t        minorversion;
 272  *              uint32_t        callback_ident;
 273  *              nfs_cb_argop4   argarray<>;
 274  *      };
 275 */
 276 static void encode_cb_compound4args(struct xdr_stream *xdr,
 277                                     struct nfs4_cb_compound_hdr *hdr)
 278 {
 279         __be32 * p;
 280
 281         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
 282         p = xdr_encode_empty_array(p);          /* empty tag */
 283         *p++ = cpu_to_be32(hdr->minorversion);
 284         *p++ = cpu_to_be32(hdr->ident);
 285
 286         hdr->nops_p = p;
 287         *p = cpu_to_be32(hdr->nops);            /* argarray element count */
 288 }
 289
 290 /*
 291  * Update argarray element count
 292  */
 293 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 294 {
 295         BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
 296         *hdr->nops_p = cpu_to_be32(hdr->nops);
 297 }
 298
 299 /*
 300  * CB_COMPOUND4res
 301  *
 302  *      struct CB_COMPOUND4res {
 303  *              nfsstat4        status;
 304  *              utf8str_cs      tag;
 305  *              nfs_cb_resop4   resarray<>;
 306  *      };
 307  */
 308 static int decode_cb_compound4res(struct xdr_stream *xdr,
 309                                   struct nfs4_cb_compound_hdr *hdr)
 310 {
 311         u32 length;
 312         __be32 *p;
 313
 314         p = xdr_inline_decode(xdr, 4 + 4);
 315         if (unlikely(p == NULL))
 316                 goto out_overflow;
 317         hdr->status = be32_to_cpup(p++);
 318         /* Ignore the tag */
 319         length = be32_to_cpup(p++);
 320         p = xdr_inline_decode(xdr, length + 4);
 321         if (unlikely(p == NULL))
 322                 goto out_overflow;
 323         p += XDR_QUADLEN(length);
 324         hdr->nops = be32_to_cpup(p);
 325         return 0;
 326 out_overflow:
 327         return -EIO;
 328 }
 329
 330 /*
 331  * CB_RECALL4args
 332  *
 333  *      struct CB_RECALL4args {
 334  *              stateid4        stateid;
 335  *              bool            truncate;
 336  *              nfs_fh4         fh;
 337  *      };
 338  */
 339 static void encode_cb_recall4args(struct xdr_stream *xdr,
 340                                   const struct nfs4_delegation *dp,
 341                                   struct nfs4_cb_compound_hdr *hdr)
 342 {
 343         __be32 *p;
 344
 345         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
 346         encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
 347
 348         p = xdr_reserve_space(xdr, 4);
 349         *p++ = xdr_zero;                        /* truncate */
 350
 351         encode_nfs_fh4(xdr, &dp->dl_stid.sc_file->fi_fhandle);
 352
 353         hdr->nops++;
 354 }
 355
 356 /*
 357  * CB_RECALLANY4args
 358  *
 359  *      struct CB_RECALLANY4args {
 360  *              uint32_t        craa_objects_to_keep;
 361  *              bitmap4         craa_type_mask;
 362  *      };
 363  */
 364 static void
 365 encode_cb_recallany4args(struct xdr_stream *xdr,
 366         struct nfs4_cb_compound_hdr *hdr, struct nfsd4_cb_recall_any *ra)
 367 {
 368         encode_nfs_cb_opnum4(xdr, OP_CB_RECALL_ANY);
 369         encode_uint32(xdr, ra->ra_keep);
 370         encode_bitmap4(xdr, ra->ra_bmval, ARRAY_SIZE(ra->ra_bmval));
 371         hdr->nops++;
 372 }
 373
 374 /*
 375  * CB_GETATTR4args
 376  *      struct CB_GETATTR4args {
 377  *         nfs_fh4 fh;
 378  *         bitmap4 attr_request;
 379  *      };
 380  *
 381  * The size and change attributes are the only one
 382  * guaranteed to be serviced by the client.
 383  */
 384 static void
 385 encode_cb_getattr4args(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr,
 386                         struct nfs4_cb_fattr *fattr)
 387 {
 388         struct nfs4_delegation *dp =
 389                 container_of(fattr, struct nfs4_delegation, dl_cb_fattr);
 390         struct knfsd_fh *fh = &dp->dl_stid.sc_file->fi_fhandle;
 391
 392         encode_nfs_cb_opnum4(xdr, OP_CB_GETATTR);
 393         encode_nfs_fh4(xdr, fh);
 394         encode_bitmap4(xdr, fattr->ncf_cb_bmap, ARRAY_SIZE(fattr->ncf_cb_bmap));
 395         hdr->nops++;
 396 }
 397
 398 /*
 399  * CB_SEQUENCE4args
 400  *
 401  *      struct CB_SEQUENCE4args {
 402  *              sessionid4              csa_sessionid;
 403  *              sequenceid4             csa_sequenceid;
 404  *              slotid4                 csa_slotid;
 405  *              slotid4                 csa_highest_slotid;
 406  *              bool                    csa_cachethis;
 407  *              referring_call_list4    csa_referring_call_lists<>;
 408  *      };
 409  */
 410 static void encode_cb_sequence4args(struct xdr_stream *xdr,
 411                                     const struct nfsd4_callback *cb,
 412                                     struct nfs4_cb_compound_hdr *hdr)
 413 {
 414         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 415         __be32 *p;
 416
 417         if (hdr->minorversion == 0)
 418                 return;
 419
 420         encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
 421         encode_sessionid4(xdr, session);
 422
 423         p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
 424         *p++ = cpu_to_be32(session->se_cb_seq_nr);      /* csa_sequenceid */
 425         *p++ = xdr_zero;                        /* csa_slotid */
 426         *p++ = xdr_zero;                        /* csa_highest_slotid */
 427         *p++ = xdr_zero;                        /* csa_cachethis */
 428         xdr_encode_empty_array(p);              /* csa_referring_call_lists */
 429
 430         hdr->nops++;
 431 }
 432
 433 /*
 434  * CB_SEQUENCE4resok
 435  *
 436  *      struct CB_SEQUENCE4resok {
 437  *              sessionid4      csr_sessionid;
 438  *              sequenceid4     csr_sequenceid;
 439  *              slotid4         csr_slotid;
 440  *              slotid4         csr_highest_slotid;
 441  *              slotid4         csr_target_highest_slotid;
 442  *      };
 443  *
 444  *      union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
 445  *      case NFS4_OK:
 446  *              CB_SEQUENCE4resok       csr_resok4;
 447  *      default:
 448  *              void;
 449  *      };
 450  *
 451  * Our current back channel implmentation supports a single backchannel
 452  * with a single slot.
 453  */
 454 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 455                                     struct nfsd4_callback *cb)
 456 {
 457         struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 458         int status = -ESERVERFAULT;
 459         __be32 *p;
 460         u32 dummy;
 461
 462         /*
 463          * If the server returns different values for sessionID, slotID or
 464          * sequence number, the server is looney tunes.
 465          */
 466         p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 467         if (unlikely(p == NULL))
 468                 goto out_overflow;
 469
 470         if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 471                 dprintk("NFS: %s Invalid session id\n", __func__);
 472                 goto out;
 473         }
 474         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 475
 476         dummy = be32_to_cpup(p++);
 477         if (dummy != session->se_cb_seq_nr) {
 478                 dprintk("NFS: %s Invalid sequence number\n", __func__);
 479                 goto out;
 480         }
 481
 482         dummy = be32_to_cpup(p++);
 483         if (dummy != 0) {
 484                 dprintk("NFS: %s Invalid slotid\n", __func__);
 485                 goto out;
 486         }
 487
 488         /*
 489          * FIXME: process highest slotid and target highest slotid
 490          */
 491         status = 0;
 492 out:
 493         cb->cb_seq_status = status;
 494         return status;
 495 out_overflow:
 496         status = -EIO;
 497         goto out;
 498 }
 499
 500 static int decode_cb_sequence4res(struct xdr_stream *xdr,
 501                                   struct nfsd4_callback *cb)
 502 {
 503         int status;
 504
 505         if (cb->cb_clp->cl_minorversion == 0)
 506                 return 0;
 507
 508         status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &cb->cb_seq_status);
 509         if (unlikely(status || cb->cb_seq_status))
 510                 return status;
 511
 512         return decode_cb_sequence4resok(xdr, cb);
 513 }
 514
 515 /*
 516  * NFSv4.0 and NFSv4.1 XDR encode functions
 517  *
 518  * NFSv4.0 callback argument types are defined in section 15 of RFC
 519  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 520  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 521  * Protocol".
 522  */
 523
 524 /*
 525  * NB: Without this zero space reservation, callbacks over krb5p fail
 526  */
 527 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 528                                  const void *__unused)
 529 {
 530         xdr_reserve_space(xdr, 0);
 531 }
 532
 533 /*
 534  * 20.1.  Operation 3: CB_GETATTR - Get Attributes
 535  */
 536 static void nfs4_xdr_enc_cb_getattr(struct rpc_rqst *req,
 537                 struct xdr_stream *xdr, const void *data)
 538 {
 539         const struct nfsd4_callback *cb = data;
 540         struct nfs4_cb_fattr *ncf =
 541                 container_of(cb, struct nfs4_cb_fattr, ncf_getattr);
 542         struct nfs4_cb_compound_hdr hdr = {
 543                 .ident = cb->cb_clp->cl_cb_ident,
 544                 .minorversion = cb->cb_clp->cl_minorversion,
 545         };
 546
 547         encode_cb_compound4args(xdr, &hdr);
 548         encode_cb_sequence4args(xdr, cb, &hdr);
 549         encode_cb_getattr4args(xdr, &hdr, ncf);
 550         encode_cb_nops(&hdr);
 551 }
 552
 553 /*
 554  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 555  */
 556 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
 557                                    const void *data)
 558 {
 559         const struct nfsd4_callback *cb = data;
 560         const struct nfs4_delegation *dp = cb_to_delegation(cb);
 561         struct nfs4_cb_compound_hdr hdr = {
 562                 .ident = cb->cb_clp->cl_cb_ident,
 563                 .minorversion = cb->cb_clp->cl_minorversion,
 564         };
 565
 566         encode_cb_compound4args(xdr, &hdr);
 567         encode_cb_sequence4args(xdr, cb, &hdr);
 568         encode_cb_recall4args(xdr, dp, &hdr);
 569         encode_cb_nops(&hdr);
 570 }
 571
 572 /*
 573  * 20.6. Operation 8: CB_RECALL_ANY - Keep Any N Recallable Objects
 574  */
 575 static void
 576 nfs4_xdr_enc_cb_recall_any(struct rpc_rqst *req,
 577                 struct xdr_stream *xdr, const void *data)
 578 {
 579         const struct nfsd4_callback *cb = data;
 580         struct nfsd4_cb_recall_any *ra;
 581         struct nfs4_cb_compound_hdr hdr = {
 582                 .ident = cb->cb_clp->cl_cb_ident,
 583                 .minorversion = cb->cb_clp->cl_minorversion,
 584         };
 585
 586         ra = container_of(cb, struct nfsd4_cb_recall_any, ra_cb);
 587         encode_cb_compound4args(xdr, &hdr);
 588         encode_cb_sequence4args(xdr, cb, &hdr);
 589         encode_cb_recallany4args(xdr, &hdr, ra);
 590         encode_cb_nops(&hdr);
 591 }
 592
 593 /*
 594  * NFSv4.0 and NFSv4.1 XDR decode functions
 595  *
 596  * NFSv4.0 callback result types are defined in section 15 of RFC
 597  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
 598  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
 599  * Protocol".
 600  */
 601
 602 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
 603                                 void *__unused)
 604 {
 605         return 0;
 606 }
 607
 608 /*
 609  * 20.1.  Operation 3: CB_GETATTR - Get Attributes
 610  */
 611 static int nfs4_xdr_dec_cb_getattr(struct rpc_rqst *rqstp,
 612                                   struct xdr_stream *xdr,
 613                                   void *data)
 614 {
 615         struct nfsd4_callback *cb = data;
 616         struct nfs4_cb_compound_hdr hdr;
 617         int status;
 618         u32 bitmap[3] = {0};
 619         u32 attrlen;
 620         struct nfs4_cb_fattr *ncf =
 621                 container_of(cb, struct nfs4_cb_fattr, ncf_getattr);
 622
 623         status = decode_cb_compound4res(xdr, &hdr);
 624         if (unlikely(status))
 625                 return status;
 626
 627         status = decode_cb_sequence4res(xdr, cb);
 628         if (unlikely(status || cb->cb_seq_status))
 629                 return status;
 630
 631         status = decode_cb_op_status(xdr, OP_CB_GETATTR, &cb->cb_status);
 632         if (status)
 633                 return status;
 634         if (xdr_stream_decode_uint32_array(xdr, bitmap, 3) < 0)
 635                 return -NFSERR_BAD_XDR;
 636         if (xdr_stream_decode_u32(xdr, &attrlen) < 0)
 637                 return -NFSERR_BAD_XDR;
 638         if (attrlen > (sizeof(ncf->ncf_cb_change) + sizeof(ncf->ncf_cb_fsize)))
 639                 return -NFSERR_BAD_XDR;
 640         status = decode_cb_fattr4(xdr, bitmap, ncf);
 641         return status;
 642 }
 643
 644 /*
 645  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
 646  */
 647 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
 648                                   struct xdr_stream *xdr,
 649                                   void *data)
 650 {
 651         struct nfsd4_callback *cb = data;
 652         struct nfs4_cb_compound_hdr hdr;
 653         int status;
 654
 655         status = decode_cb_compound4res(xdr, &hdr);
 656         if (unlikely(status))
 657                 return status;
 658
 659         status = decode_cb_sequence4res(xdr, cb);
 660         if (unlikely(status || cb->cb_seq_status))
 661                 return status;
 662
 663         return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
 664 }
 665
 666 /*
 667  * 20.6. Operation 8: CB_RECALL_ANY - Keep Any N Recallable Objects
 668  */
 669 static int
 670 nfs4_xdr_dec_cb_recall_any(struct rpc_rqst *rqstp,
 671                                   struct xdr_stream *xdr,
 672                                   void *data)
 673 {
 674         struct nfsd4_callback *cb = data;
 675         struct nfs4_cb_compound_hdr hdr;
 676         int status;
 677
 678         status = decode_cb_compound4res(xdr, &hdr);
 679         if (unlikely(status))
 680                 return status;
 681         status = decode_cb_sequence4res(xdr, cb);
 682         if (unlikely(status || cb->cb_seq_status))
 683                 return status;
 684         status =  decode_cb_op_status(xdr, OP_CB_RECALL_ANY, &cb->cb_status);
 685         return status;
 686 }
 687
 688 #ifdef CONFIG_NFSD_PNFS
 689 /*
 690  * CB_LAYOUTRECALL4args
 691  *
 692  *      struct layoutrecall_file4 {
 693  *              nfs_fh4         lor_fh;
 694  *              offset4         lor_offset;
 695  *              length4         lor_length;
 696  *              stateid4        lor_stateid;
 697  *      };
 698  *
 699  *      union layoutrecall4 switch(layoutrecall_type4 lor_recalltype) {
 700  *      case LAYOUTRECALL4_FILE:
 701  *              layoutrecall_file4 lor_layout;
 702  *      case LAYOUTRECALL4_FSID:
 703  *              fsid4              lor_fsid;
 704  *      case LAYOUTRECALL4_ALL:
 705  *              void;
 706  *      };
 707  *
 708  *      struct CB_LAYOUTRECALL4args {
 709  *              layouttype4             clora_type;
 710  *              layoutiomode4           clora_iomode;
 711  *              bool                    clora_changed;
 712  *              layoutrecall4           clora_recall;
 713  *      };
 714  */
 715 static void encode_cb_layout4args(struct xdr_stream *xdr,
 716                                   const struct nfs4_layout_stateid *ls,
 717                                   struct nfs4_cb_compound_hdr *hdr)
 718 {
 719         __be32 *p;
 720
 721         BUG_ON(hdr->minorversion == 0);
 722
 723         p = xdr_reserve_space(xdr, 5 * 4);
 724         *p++ = cpu_to_be32(OP_CB_LAYOUTRECALL);
 725         *p++ = cpu_to_be32(ls->ls_layout_type);
 726         *p++ = cpu_to_be32(IOMODE_ANY);
 727         *p++ = cpu_to_be32(1);
 728         *p = cpu_to_be32(RETURN_FILE);
 729
 730         encode_nfs_fh4(xdr, &ls->ls_stid.sc_file->fi_fhandle);
 731
 732         p = xdr_reserve_space(xdr, 2 * 8);
 733         p = xdr_encode_hyper(p, 0);
 734         xdr_encode_hyper(p, NFS4_MAX_UINT64);
 735
 736         encode_stateid4(xdr, &ls->ls_recall_sid);
 737
 738         hdr->nops++;
 739 }
 740
 741 static void nfs4_xdr_enc_cb_layout(struct rpc_rqst *req,
 742                                    struct xdr_stream *xdr,
 743                                    const void *data)
 744 {
 745         const struct nfsd4_callback *cb = data;
 746         const struct nfs4_layout_stateid *ls =
 747                 container_of(cb, struct nfs4_layout_stateid, ls_recall);
 748         struct nfs4_cb_compound_hdr hdr = {
 749                 .ident = 0,
 750                 .minorversion = cb->cb_clp->cl_minorversion,
 751         };
 752
 753         encode_cb_compound4args(xdr, &hdr);
 754         encode_cb_sequence4args(xdr, cb, &hdr);
 755         encode_cb_layout4args(xdr, ls, &hdr);
 756         encode_cb_nops(&hdr);
 757 }
 758
 759 static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
 760                                   struct xdr_stream *xdr,
 761                                   void *data)
 762 {
 763         struct nfsd4_callback *cb = data;
 764         struct nfs4_cb_compound_hdr hdr;
 765         int status;
 766
 767         status = decode_cb_compound4res(xdr, &hdr);
 768         if (unlikely(status))
 769                 return status;
 770
 771         status = decode_cb_sequence4res(xdr, cb);
 772         if (unlikely(status || cb->cb_seq_status))
 773                 return status;
 774
 775         return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
 776 }
 777 #endif /* CONFIG_NFSD_PNFS */
 778
 779 static void encode_stateowner(struct xdr_stream *xdr, struct nfs4_stateowner *so)
 780 {
 781         __be32  *p;
 782
 783         p = xdr_reserve_space(xdr, 8 + 4 + so->so_owner.len);
 784         p = xdr_encode_opaque_fixed(p, &so->so_client->cl_clientid, 8);
 785         xdr_encode_opaque(p, so->so_owner.data, so->so_owner.len);
 786 }
 787
 788 static void nfs4_xdr_enc_cb_notify_lock(struct rpc_rqst *req,
 789                                         struct xdr_stream *xdr,
 790                                         const void *data)
 791 {
 792         const struct nfsd4_callback *cb = data;
 793         const struct nfsd4_blocked_lock *nbl =
 794                 container_of(cb, struct nfsd4_blocked_lock, nbl_cb);
 795         struct nfs4_lockowner *lo = (struct nfs4_lockowner *)nbl->nbl_lock.fl_owner;
 796         struct nfs4_cb_compound_hdr hdr = {
 797                 .ident = 0,
 798                 .minorversion = cb->cb_clp->cl_minorversion,
 799         };
 800
 801         __be32 *p;
 802
 803         BUG_ON(hdr.minorversion == 0);
 804
 805         encode_cb_compound4args(xdr, &hdr);
 806         encode_cb_sequence4args(xdr, cb, &hdr);
 807
 808         p = xdr_reserve_space(xdr, 4);
 809         *p = cpu_to_be32(OP_CB_NOTIFY_LOCK);
 810         encode_nfs_fh4(xdr, &nbl->nbl_fh);
 811         encode_stateowner(xdr, &lo->lo_owner);
 812         hdr.nops++;
 813
 814         encode_cb_nops(&hdr);
 815 }
 816
 817 static int nfs4_xdr_dec_cb_notify_lock(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_NOTIFY_LOCK, &cb->cb_status);
 834 }
 835
 836 /*
 837  * struct write_response4 {
 838  *      stateid4        wr_callback_id<1>;
 839  *      length4         wr_count;
 840  *      stable_how4     wr_committed;
 841  *      verifier4       wr_writeverf;
 842  * };
 843  * union offload_info4 switch (nfsstat4 coa_status) {
 844  *      case NFS4_OK:
 845  *              write_response4 coa_resok4;
 846  *      default:
 847  *              length4         coa_bytes_copied;
 848  * };
 849  * struct CB_OFFLOAD4args {
 850  *      nfs_fh4         coa_fh;
 851  *      stateid4        coa_stateid;
 852  *      offload_info4   coa_offload_info;
 853  * };
 854  */
 855 static void encode_offload_info4(struct xdr_stream *xdr,
 856                                  const struct nfsd4_cb_offload *cbo)
 857 {
 858         __be32 *p;
 859
 860         p = xdr_reserve_space(xdr, 4);
 861         *p = cbo->co_nfserr;
 862         switch (cbo->co_nfserr) {
 863         case nfs_ok:
 864                 p = xdr_reserve_space(xdr, 4 + 8 + 4 + NFS4_VERIFIER_SIZE);
 865                 p = xdr_encode_empty_array(p);
 866                 p = xdr_encode_hyper(p, cbo->co_res.wr_bytes_written);
 867                 *p++ = cpu_to_be32(cbo->co_res.wr_stable_how);
 868                 p = xdr_encode_opaque_fixed(p, cbo->co_res.wr_verifier.data,
 869                                             NFS4_VERIFIER_SIZE);
 870                 break;
 871         default:
 872                 p = xdr_reserve_space(xdr, 8);
 873                 /* We always return success if bytes were written */
 874                 p = xdr_encode_hyper(p, 0);
 875         }
 876 }
 877
 878 static void encode_cb_offload4args(struct xdr_stream *xdr,
 879                                    const struct nfsd4_cb_offload *cbo,
 880                                    struct nfs4_cb_compound_hdr *hdr)
 881 {
 882         __be32 *p;
 883
 884         p = xdr_reserve_space(xdr, 4);
 885         *p = cpu_to_be32(OP_CB_OFFLOAD);
 886         encode_nfs_fh4(xdr, &cbo->co_fh);
 887         encode_stateid4(xdr, &cbo->co_res.cb_stateid);
 888         encode_offload_info4(xdr, cbo);
 889
 890         hdr->nops++;
 891 }
 892
 893 static void nfs4_xdr_enc_cb_offload(struct rpc_rqst *req,
 894                                     struct xdr_stream *xdr,
 895                                     const void *data)
 896 {
 897         const struct nfsd4_callback *cb = data;
 898         const struct nfsd4_cb_offload *cbo =
 899                 container_of(cb, struct nfsd4_cb_offload, co_cb);
 900         struct nfs4_cb_compound_hdr hdr = {
 901                 .ident = 0,
 902                 .minorversion = cb->cb_clp->cl_minorversion,
 903         };
 904
 905         encode_cb_compound4args(xdr, &hdr);
 906         encode_cb_sequence4args(xdr, cb, &hdr);
 907         encode_cb_offload4args(xdr, cbo, &hdr);
 908         encode_cb_nops(&hdr);
 909 }
 910
 911 static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
 912                                    struct xdr_stream *xdr,
 913                                    void *data)
 914 {
 915         struct nfsd4_callback *cb = data;
 916         struct nfs4_cb_compound_hdr hdr;
 917         int status;
 918
 919         status = decode_cb_compound4res(xdr, &hdr);
 920         if (unlikely(status))
 921                 return status;
 922
 923         status = decode_cb_sequence4res(xdr, cb);
 924         if (unlikely(status || cb->cb_seq_status))
 925                 return status;
 926
 927         return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
 928 }
 929 /*
 930  * RPC procedure tables
 931  */
 932 #define PROC(proc, call, argtype, restype)                              \
 933 [NFSPROC4_CLNT_##proc] = {                                              \
 934         .p_proc    = NFSPROC4_CB_##call,                                \
 935         .p_encode  = nfs4_xdr_enc_##argtype,            \
 936         .p_decode  = nfs4_xdr_dec_##restype,                            \
 937         .p_arglen  = NFS4_enc_##argtype##_sz,                           \
 938         .p_replen  = NFS4_dec_##restype##_sz,                           \
 939         .p_statidx = NFSPROC4_CB_##call,                                \
 940         .p_name    = #proc,                                             \
 941 }
 942
 943 static const struct rpc_procinfo nfs4_cb_procedures[] = {
 944         PROC(CB_NULL,   NULL,           cb_null,        cb_null),
 945         PROC(CB_RECALL, COMPOUND,       cb_recall,      cb_recall),
 946 #ifdef CONFIG_NFSD_PNFS
 947         PROC(CB_LAYOUT, COMPOUND,       cb_layout,      cb_layout),
 948 #endif
 949         PROC(CB_NOTIFY_LOCK,    COMPOUND,       cb_notify_lock, cb_notify_lock),
 950         PROC(CB_OFFLOAD,        COMPOUND,       cb_offload,     cb_offload),
 951         PROC(CB_RECALL_ANY,     COMPOUND,       cb_recall_any,  cb_recall_any),
 952         PROC(CB_GETATTR,        COMPOUND,       cb_getattr,     cb_getattr),
 953 };
 954
 955 static unsigned int nfs4_cb_counts[ARRAY_SIZE(nfs4_cb_procedures)];
 956 static const struct rpc_version nfs_cb_version4 = {
 957 /*
 958  * Note on the callback rpc program version number: despite language in rfc
 959  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 960  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 961  * in practice that appears to be what implementations use.  The section
 962  * 18.36.3 language is expected to be fixed in an erratum.
 963  */
 964         .number                 = 1,
 965         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 966         .procs                  = nfs4_cb_procedures,
 967         .counts                 = nfs4_cb_counts,
 968 };
 969
 970 static const struct rpc_version *nfs_cb_version[2] = {
 971         [1] = &nfs_cb_version4,
 972 };
 973
 974 static const struct rpc_program cb_program;
 975
 976 static struct rpc_stat cb_stats = {
 977         .program                = &cb_program
 978 };
 979
 980 #define NFS4_CALLBACK 0x40000000
 981 static const struct rpc_program cb_program = {
 982         .name                   = "nfs4_cb",
 983         .number                 = NFS4_CALLBACK,
 984         .nrvers                 = ARRAY_SIZE(nfs_cb_version),
 985         .version                = nfs_cb_version,
 986         .stats                  = &cb_stats,
 987         .pipe_dir_name          = "nfsd4_cb",
 988 };
 989
 990 static int max_cb_time(struct net *net)
 991 {
 992         struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 993
 994         /*
 995          * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
 996          * so we can use 32-bit math on it. Warn if that assumption
 997          * ever stops being true.
 998          */
 999         if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
1000                 return 360 * HZ;
1001
1002         return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
1003 }
1004
1005 static struct workqueue_struct *callback_wq;
1006
1007 static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
1008 {
1009         return queue_work(callback_wq, &cb->cb_work);
1010 }
1011
1012 static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
1013 {
1014         atomic_inc(&clp->cl_cb_inflight);
1015 }
1016
1017 static void nfsd41_cb_inflight_end(struct nfs4_client *clp)
1018 {
1019
1020         if (atomic_dec_and_test(&clp->cl_cb_inflight))
1021                 wake_up_var(&clp->cl_cb_inflight);
1022 }
1023
1024 static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp)
1025 {
1026         wait_var_event(&clp->cl_cb_inflight,
1027                         !atomic_read(&clp->cl_cb_inflight));
1028 }
1029
1030 static const struct cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
1031 {
1032         if (clp->cl_minorversion == 0) {
1033                 client->cl_principal = clp->cl_cred.cr_targ_princ ?
1034                         clp->cl_cred.cr_targ_princ : "nfs";
1035
1036                 return get_cred(rpc_machine_cred());
1037         } else {
1038                 struct cred *kcred;
1039
1040                 kcred = prepare_kernel_cred(&init_task);
1041                 if (!kcred)
1042                         return NULL;
1043
1044                 kcred->fsuid = ses->se_cb_sec.uid;
1045                 kcred->fsgid = ses->se_cb_sec.gid;
1046                 return kcred;
1047         }
1048 }
1049
1050 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
1051 {
1052         int maxtime = max_cb_time(clp->net);
1053         struct rpc_timeout      timeparms = {
1054                 .to_initval     = maxtime,
1055                 .to_retries     = 0,
1056                 .to_maxval      = maxtime,
1057         };
1058         struct rpc_create_args args = {
1059                 .net            = clp->net,
1060                 .address        = (struct sockaddr *) &conn->cb_addr,
1061                 .addrsize       = conn->cb_addrlen,
1062                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
1063                 .timeout        = &timeparms,
1064                 .program        = &cb_program,
1065                 .version        = 1,
1066                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
1067                 .cred           = current_cred(),
1068         };
1069         struct rpc_clnt *client;
1070         const struct cred *cred;
1071
1072         if (clp->cl_minorversion == 0) {
1073                 if (!clp->cl_cred.cr_principal &&
1074                     (clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5)) {
1075                         trace_nfsd_cb_setup_err(clp, -EINVAL);
1076                         return -EINVAL;
1077                 }
1078                 args.client_name = clp->cl_cred.cr_principal;
1079                 args.prognumber = conn->cb_prog;
1080                 args.protocol = XPRT_TRANSPORT_TCP;
1081                 args.authflavor = clp->cl_cred.cr_flavor;
1082                 clp->cl_cb_ident = conn->cb_ident;
1083         } else {
1084                 if (!conn->cb_xprt)
1085                         return -EINVAL;
1086                 clp->cl_cb_session = ses;
1087                 args.bc_xprt = conn->cb_xprt;
1088                 args.prognumber = clp->cl_cb_session->se_cb_prog;
1089                 args.protocol = conn->cb_xprt->xpt_class->xcl_ident |
1090                                 XPRT_TRANSPORT_BC;
1091                 args.authflavor = ses->se_cb_sec.flavor;
1092         }
1093         /* Create RPC client */
1094         client = rpc_create(&args);
1095         if (IS_ERR(client)) {
1096                 trace_nfsd_cb_setup_err(clp, PTR_ERR(client));
1097                 return PTR_ERR(client);
1098         }
1099         cred = get_backchannel_cred(clp, client, ses);
1100         if (!cred) {
1101                 trace_nfsd_cb_setup_err(clp, -ENOMEM);
1102                 rpc_shutdown_client(client);
1103                 return -ENOMEM;
1104         }
1105
1106         if (clp->cl_minorversion != 0)
1107                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
1108         clp->cl_cb_client = client;
1109         clp->cl_cb_cred = cred;
1110         rcu_read_lock();
1111         trace_nfsd_cb_setup(clp, rpc_peeraddr2str(client, RPC_DISPLAY_NETID),
1112                             args.authflavor);
1113         rcu_read_unlock();
1114         return 0;
1115 }
1116
1117 static void nfsd4_mark_cb_state(struct nfs4_client *clp, int newstate)
1118 {
1119         if (clp->cl_cb_state != newstate) {
1120                 clp->cl_cb_state = newstate;
1121                 trace_nfsd_cb_state(clp);
1122         }
1123 }
1124
1125 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
1126 {
1127         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
1128                 return;
1129         nfsd4_mark_cb_state(clp, NFSD4_CB_DOWN);
1130 }
1131
1132 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
1133 {
1134         if (test_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags))
1135                 return;
1136         nfsd4_mark_cb_state(clp, NFSD4_CB_FAULT);
1137 }
1138
1139 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
1140 {
1141         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
1142
1143         if (task->tk_status)
1144                 nfsd4_mark_cb_down(clp, task->tk_status);
1145         else
1146                 nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1147 }
1148
1149 static void nfsd4_cb_probe_release(void *calldata)
1150 {
1151         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
1152
1153         nfsd41_cb_inflight_end(clp);
1154
1155 }
1156
1157 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
1158         /* XXX: release method to ensure we set the cb channel down if
1159          * necessary on early failure? */
1160         .rpc_call_done = nfsd4_cb_probe_done,
1161         .rpc_release = nfsd4_cb_probe_release,
1162 };
1163
1164 /*
1165  * Poke the callback thread to process any updates to the callback
1166  * parameters, and send a null probe.
1167  */
1168 void nfsd4_probe_callback(struct nfs4_client *clp)
1169 {
1170         trace_nfsd_cb_probe(clp);
1171         nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1172         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1173         nfsd4_run_cb(&clp->cl_cb_null);
1174 }
1175
1176 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
1177 {
1178         nfsd4_probe_callback(clp);
1179         flush_workqueue(callback_wq);
1180 }
1181
1182 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
1183 {
1184         nfsd4_mark_cb_state(clp, NFSD4_CB_UNKNOWN);
1185         spin_lock(&clp->cl_lock);
1186         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
1187         spin_unlock(&clp->cl_lock);
1188 }
1189
1190 /*
1191  * There's currently a single callback channel slot.
1192  * If the slot is available, then mark it busy.  Otherwise, set the
1193  * thread for sleeping on the callback RPC wait queue.
1194  */
1195 static bool nfsd41_cb_get_slot(struct nfsd4_callback *cb, struct rpc_task *task)
1196 {
1197         struct nfs4_client *clp = cb->cb_clp;
1198
1199         if (!cb->cb_holds_slot &&
1200             test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1201                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
1202                 /* Race breaker */
1203                 if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
1204                         dprintk("%s slot is busy\n", __func__);
1205                         return false;
1206                 }
1207                 rpc_wake_up_queued_task(&clp->cl_cb_waitq, task);
1208         }
1209         cb->cb_holds_slot = true;
1210         return true;
1211 }
1212
1213 static void nfsd41_cb_release_slot(struct nfsd4_callback *cb)
1214 {
1215         struct nfs4_client *clp = cb->cb_clp;
1216
1217         if (cb->cb_holds_slot) {
1218                 cb->cb_holds_slot = false;
1219                 clear_bit(0, &clp->cl_cb_slot_busy);
1220                 rpc_wake_up_next(&clp->cl_cb_waitq);
1221         }
1222 }
1223
1224 static void nfsd41_destroy_cb(struct nfsd4_callback *cb)
1225 {
1226         struct nfs4_client *clp = cb->cb_clp;
1227
1228         nfsd41_cb_release_slot(cb);
1229         if (cb->cb_ops && cb->cb_ops->release)
1230                 cb->cb_ops->release(cb);
1231         nfsd41_cb_inflight_end(clp);
1232 }
1233
1234 /*
1235  * TODO: cb_sequence should support referring call lists, cachethis, multiple
1236  * slots, and mark callback channel down on communication errors.
1237  */
1238 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
1239 {
1240         struct nfsd4_callback *cb = calldata;
1241         struct nfs4_client *clp = cb->cb_clp;
1242         u32 minorversion = clp->cl_minorversion;
1243
1244         /*
1245          * cb_seq_status is only set in decode_cb_sequence4res,
1246          * and so will remain 1 if an rpc level failure occurs.
1247          */
1248         cb->cb_seq_status = 1;
1249         cb->cb_status = 0;
1250         if (minorversion && !nfsd41_cb_get_slot(cb, task))
1251                 return;
1252         rpc_call_start(task);
1253 }
1254
1255 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
1256 {
1257         struct nfs4_client *clp = cb->cb_clp;
1258         struct nfsd4_session *session = clp->cl_cb_session;
1259         bool ret = true;
1260
1261         if (!clp->cl_minorversion) {
1262                 /*
1263                  * If the backchannel connection was shut down while this
1264                  * task was queued, we need to resubmit it after setting up
1265                  * a new backchannel connection.
1266                  *
1267                  * Note that if we lost our callback connection permanently
1268                  * the submission code will error out, so we don't need to
1269                  * handle that case here.
1270                  */
1271                 if (RPC_SIGNALLED(task))
1272                         goto need_restart;
1273
1274                 return true;
1275         }
1276
1277         if (!cb->cb_holds_slot)
1278                 goto need_restart;
1279
1280         switch (cb->cb_seq_status) {
1281         case 0:
1282                 /*
1283                  * No need for lock, access serialized in nfsd4_cb_prepare
1284                  *
1285                  * RFC5661 20.9.3
1286                  * If CB_SEQUENCE returns an error, then the state of the slot
1287                  * (sequence ID, cached reply) MUST NOT change.
1288                  */
1289                 ++session->se_cb_seq_nr;
1290                 break;
1291         case -ESERVERFAULT:
1292                 ++session->se_cb_seq_nr;
1293                 fallthrough;
1294         case 1:
1295         case -NFS4ERR_BADSESSION:
1296                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1297                 ret = false;
1298                 break;
1299         case -NFS4ERR_DELAY:
1300                 if (!rpc_restart_call(task))
1301                         goto out;
1302
1303                 rpc_delay(task, 2 * HZ);
1304                 return false;
1305         case -NFS4ERR_BADSLOT:
1306                 goto retry_nowait;
1307         case -NFS4ERR_SEQ_MISORDERED:
1308                 if (session->se_cb_seq_nr != 1) {
1309                         session->se_cb_seq_nr = 1;
1310                         goto retry_nowait;
1311                 }
1312                 break;
1313         default:
1314                 nfsd4_mark_cb_fault(cb->cb_clp, cb->cb_seq_status);
1315                 dprintk("%s: unprocessed error %d\n", __func__,
1316                         cb->cb_seq_status);
1317         }
1318
1319         nfsd41_cb_release_slot(cb);
1320         dprintk("%s: freed slot, new seqid=%d\n", __func__,
1321                 clp->cl_cb_session->se_cb_seq_nr);
1322
1323         if (RPC_SIGNALLED(task))
1324                 goto need_restart;
1325 out:
1326         return ret;
1327 retry_nowait:
1328         if (rpc_restart_call_prepare(task))
1329                 ret = false;
1330         goto out;
1331 need_restart:
1332         if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
1333                 task->tk_status = 0;
1334                 cb->cb_need_restart = true;
1335         }
1336         return false;
1337 }
1338
1339 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
1340 {
1341         struct nfsd4_callback *cb = calldata;
1342         struct nfs4_client *clp = cb->cb_clp;
1343
1344         if (!nfsd4_cb_sequence_done(task, cb))
1345                 return;
1346
1347         if (cb->cb_status) {
1348                 WARN_ON_ONCE(task->tk_status);
1349                 task->tk_status = cb->cb_status;
1350         }
1351
1352         switch (cb->cb_ops->done(cb, task)) {
1353         case 0:
1354                 task->tk_status = 0;
1355                 rpc_restart_call_prepare(task);
1356                 return;
1357         case 1:
1358                 switch (task->tk_status) {
1359                 case -EIO:
1360                 case -ETIMEDOUT:
1361                 case -EACCES:
1362                         nfsd4_mark_cb_down(clp, task->tk_status);
1363                 }
1364                 break;
1365         default:
1366                 BUG();
1367         }
1368 }
1369
1370 static void nfsd4_cb_release(void *calldata)
1371 {
1372         struct nfsd4_callback *cb = calldata;
1373
1374         if (cb->cb_need_restart)
1375                 nfsd4_queue_cb(cb);
1376         else
1377                 nfsd41_destroy_cb(cb);
1378
1379 }
1380
1381 static const struct rpc_call_ops nfsd4_cb_ops = {
1382         .rpc_call_prepare = nfsd4_cb_prepare,
1383         .rpc_call_done = nfsd4_cb_done,
1384         .rpc_release = nfsd4_cb_release,
1385 };
1386
1387 int nfsd4_create_callback_queue(void)
1388 {
1389         callback_wq = alloc_ordered_workqueue("nfsd4_callbacks", 0);
1390         if (!callback_wq)
1391                 return -ENOMEM;
1392         return 0;
1393 }
1394
1395 void nfsd4_destroy_callback_queue(void)
1396 {
1397         destroy_workqueue(callback_wq);
1398 }
1399
1400 /* must be called under the state lock */
1401 void nfsd4_shutdown_callback(struct nfs4_client *clp)
1402 {
1403         if (clp->cl_cb_state != NFSD4_CB_UNKNOWN)
1404                 trace_nfsd_cb_shutdown(clp);
1405
1406         set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
1407         /*
1408          * Note this won't actually result in a null callback;
1409          * instead, nfsd4_run_cb_null() will detect the killed
1410          * client, destroy the rpc client, and stop:
1411          */
1412         nfsd4_run_cb(&clp->cl_cb_null);
1413         flush_workqueue(callback_wq);
1414         nfsd41_cb_inflight_wait_complete(clp);
1415 }
1416
1417 /* requires cl_lock: */
1418 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
1419 {
1420         struct nfsd4_session *s;
1421         struct nfsd4_conn *c;
1422
1423         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
1424                 list_for_each_entry(c, &s->se_conns, cn_persession) {
1425                         if (c->cn_flags & NFS4_CDFC4_BACK)
1426                                 return c;
1427                 }
1428         }
1429         return NULL;
1430 }
1431
1432 /*
1433  * Note there isn't a lot of locking in this code; instead we depend on
1434  * the fact that it is run from the callback_wq, which won't run two
1435  * work items at once.  So, for example, callback_wq handles all access
1436  * of cl_cb_client and all calls to rpc_create or rpc_shutdown_client.
1437  */
1438 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
1439 {
1440         struct nfs4_cb_conn conn;
1441         struct nfs4_client *clp = cb->cb_clp;
1442         struct nfsd4_session *ses = NULL;
1443         struct nfsd4_conn *c;
1444         int err;
1445
1446         /*
1447          * This is either an update, or the client dying; in either case,
1448          * kill the old client:
1449          */
1450         if (clp->cl_cb_client) {
1451                 rpc_shutdown_client(clp->cl_cb_client);
1452                 clp->cl_cb_client = NULL;
1453                 put_cred(clp->cl_cb_cred);
1454                 clp->cl_cb_cred = NULL;
1455         }
1456         if (clp->cl_cb_conn.cb_xprt) {
1457                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
1458                 clp->cl_cb_conn.cb_xprt = NULL;
1459         }
1460         if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
1461                 return;
1462         spin_lock(&clp->cl_lock);
1463         /*
1464          * Only serialized callback code is allowed to clear these
1465          * flags; main nfsd code can only set them:
1466          */
1467         BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
1468         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
1469         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
1470         c = __nfsd4_find_backchannel(clp);
1471         if (c) {
1472                 svc_xprt_get(c->cn_xprt);
1473                 conn.cb_xprt = c->cn_xprt;
1474                 ses = c->cn_session;
1475         }
1476         spin_unlock(&clp->cl_lock);
1477
1478         err = setup_callback_client(clp, &conn, ses);
1479         if (err) {
1480                 nfsd4_mark_cb_down(clp, err);
1481                 if (c)
1482                         svc_xprt_put(c->cn_xprt);
1483                 return;
1484         }
1485 }
1486
1487 static void
1488 nfsd4_run_cb_work(struct work_struct *work)
1489 {
1490         struct nfsd4_callback *cb =
1491                 container_of(work, struct nfsd4_callback, cb_work);
1492         struct nfs4_client *clp = cb->cb_clp;
1493         struct rpc_clnt *clnt;
1494         int flags;
1495
1496         if (cb->cb_need_restart) {
1497                 cb->cb_need_restart = false;
1498         } else {
1499                 if (cb->cb_ops && cb->cb_ops->prepare)
1500                         cb->cb_ops->prepare(cb);
1501         }
1502
1503         if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1504                 nfsd4_process_cb_update(cb);
1505
1506         clnt = clp->cl_cb_client;
1507         if (!clnt) {
1508                 /* Callback channel broken, or client killed; give up: */
1509                 nfsd41_destroy_cb(cb);
1510                 return;
1511         }
1512
1513         /*
1514          * Don't send probe messages for 4.1 or later.
1515          */
1516         if (!cb->cb_ops && clp->cl_minorversion) {
1517                 nfsd4_mark_cb_state(clp, NFSD4_CB_UP);
1518                 nfsd41_destroy_cb(cb);
1519                 return;
1520         }
1521
1522         cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1523         flags = clp->cl_minorversion ? RPC_TASK_NOCONNECT : RPC_TASK_SOFTCONN;
1524         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | flags,
1525                         cb->cb_ops ? &nfsd4_cb_ops : &nfsd4_cb_probe_ops, cb);
1526 }
1527
1528 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
1529                 const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
1530 {
1531         cb->cb_clp = clp;
1532         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];
1533         cb->cb_msg.rpc_argp = cb;
1534         cb->cb_msg.rpc_resp = cb;
1535         cb->cb_ops = ops;
1536         INIT_WORK(&cb->cb_work, nfsd4_run_cb_work);
1537         cb->cb_seq_status = 1;
1538         cb->cb_status = 0;
1539         cb->cb_need_restart = false;
1540         cb->cb_holds_slot = false;
1541 }
1542
1543 /**
1544  * nfsd4_run_cb - queue up a callback job to run
1545  * @cb: callback to queue
1546  *
1547  * Kick off a callback to do its thing. Returns false if it was already
1548  * on a queue, true otherwise.
1549  */
1550 bool nfsd4_run_cb(struct nfsd4_callback *cb)
1551 {
1552         struct nfs4_client *clp = cb->cb_clp;
1553         bool queued;
1554
1555         nfsd41_cb_inflight_begin(clp);
1556         queued = nfsd4_queue_cb(cb);
1557         if (!queued)
1558                 nfsd41_cb_inflight_end(clp);
1559         return queued;
1560 }