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/svc_xprt.h>
  36 #include "nfsd.h"
  37 #include "state.h"
  38
  39 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  40
  41 #define NFSPROC4_CB_NULL 0
  42 #define NFSPROC4_CB_COMPOUND 1
  43 #define NFS4_STATEID_SIZE 16
  44
  45 /* Index of predefined Linux callback client operations */
  46
  47 enum {
  48         NFSPROC4_CLNT_CB_NULL = 0,
  49         NFSPROC4_CLNT_CB_RECALL,
  50         NFSPROC4_CLNT_CB_SEQUENCE,
  51 };
  52
  53 enum nfs_cb_opnum4 {
  54         OP_CB_RECALL            = 4,
  55         OP_CB_SEQUENCE          = 11,
  56 };
  57
  58 #define NFS4_MAXTAGLEN          20
  59
  60 #define NFS4_enc_cb_null_sz             0
  61 #define NFS4_dec_cb_null_sz             0
  62 #define cb_compound_enc_hdr_sz          4
  63 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
  64 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
  65 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
  66                                         1 /* no referring calls list yet */)
  67 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
  68
  69 #define op_enc_sz                       1
  70 #define op_dec_sz                       2
  71 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
  72 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
  73 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
  74                                         cb_sequence_enc_sz +            \
  75                                         1 + enc_stateid_sz +            \
  76                                         enc_nfs4_fh_sz)
  77
  78 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
  79                                         cb_sequence_dec_sz +            \
  80                                         op_dec_sz)
  81
  82 /*
  83 * Generic encode routines from fs/nfs/nfs4xdr.c
  84 */
  85 static inline __be32 *
  86 xdr_writemem(__be32 *p, const void *ptr, int nbytes)
  87 {
  88         int tmp = XDR_QUADLEN(nbytes);
  89         if (!tmp)
  90                 return p;
  91         p[tmp-1] = 0;
  92         memcpy(p, ptr, nbytes);
  93         return p + tmp;
  94 }
  95
  96 #define WRITE32(n)               *p++ = htonl(n)
  97 #define WRITEMEM(ptr,nbytes)     do {                           \
  98         p = xdr_writemem(p, ptr, nbytes);                       \
  99 } while (0)
 100 #define RESERVE_SPACE(nbytes)   do {                            \
 101         p = xdr_reserve_space(xdr, nbytes);                     \
 102         if (!p) dprintk("NFSD: RESERVE_SPACE(%d) failed in function %s\n", (int) (nbytes), __func__); \
 103         BUG_ON(!p);                                             \
 104 } while (0)
 105
 106 /*
 107  * Generic decode routines from fs/nfs/nfs4xdr.c
 108  */
 109 #define DECODE_TAIL                             \
 110         status = 0;                             \
 111 out:                                            \
 112         return status;                          \
 113 xdr_error:                                      \
 114         dprintk("NFSD: xdr error! (%s:%d)\n", __FILE__, __LINE__); \
 115         status = -EIO;                          \
 116         goto out
 117
 118 #define READ32(x)         (x) = ntohl(*p++)
 119 #define READ64(x)         do {                  \
 120         (x) = (u64)ntohl(*p++) << 32;           \
 121         (x) |= ntohl(*p++);                     \
 122 } while (0)
 123 #define READTIME(x)       do {                  \
 124         p++;                                    \
 125         (x.tv_sec) = ntohl(*p++);               \
 126         (x.tv_nsec) = ntohl(*p++);              \
 127 } while (0)
 128 #define READ_BUF(nbytes)  do { \
 129         p = xdr_inline_decode(xdr, nbytes); \
 130         if (!p) { \
 131                 dprintk("NFSD: %s: reply buffer overflowed in line %d.\n", \
 132                         __func__, __LINE__); \
 133                 return -EIO; \
 134         } \
 135 } while (0)
 136
 137 struct nfs4_cb_compound_hdr {
 138         /* args */
 139         u32             ident;  /* minorversion 0 only */
 140         u32             nops;
 141         __be32          *nops_p;
 142         u32             minorversion;
 143         /* res */
 144         int             status;
 145         u32             taglen;
 146         char            *tag;
 147 };
 148
 149 static struct {
 150 int stat;
 151 int errno;
 152 } nfs_cb_errtbl[] = {
 153         { NFS4_OK,              0               },
 154         { NFS4ERR_PERM,         EPERM           },
 155         { NFS4ERR_NOENT,        ENOENT          },
 156         { NFS4ERR_IO,           EIO             },
 157         { NFS4ERR_NXIO,         ENXIO           },
 158         { NFS4ERR_ACCESS,       EACCES          },
 159         { NFS4ERR_EXIST,        EEXIST          },
 160         { NFS4ERR_XDEV,         EXDEV           },
 161         { NFS4ERR_NOTDIR,       ENOTDIR         },
 162         { NFS4ERR_ISDIR,        EISDIR          },
 163         { NFS4ERR_INVAL,        EINVAL          },
 164         { NFS4ERR_FBIG,         EFBIG           },
 165         { NFS4ERR_NOSPC,        ENOSPC          },
 166         { NFS4ERR_ROFS,         EROFS           },
 167         { NFS4ERR_MLINK,        EMLINK          },
 168         { NFS4ERR_NAMETOOLONG,  ENAMETOOLONG    },
 169         { NFS4ERR_NOTEMPTY,     ENOTEMPTY       },
 170         { NFS4ERR_DQUOT,        EDQUOT          },
 171         { NFS4ERR_STALE,        ESTALE          },
 172         { NFS4ERR_BADHANDLE,    EBADHANDLE      },
 173         { NFS4ERR_BAD_COOKIE,   EBADCOOKIE      },
 174         { NFS4ERR_NOTSUPP,      ENOTSUPP        },
 175         { NFS4ERR_TOOSMALL,     ETOOSMALL       },
 176         { NFS4ERR_SERVERFAULT,  ESERVERFAULT    },
 177         { NFS4ERR_BADTYPE,      EBADTYPE        },
 178         { NFS4ERR_LOCKED,       EAGAIN          },
 179         { NFS4ERR_RESOURCE,     EREMOTEIO       },
 180         { NFS4ERR_SYMLINK,      ELOOP           },
 181         { NFS4ERR_OP_ILLEGAL,   EOPNOTSUPP      },
 182         { NFS4ERR_DEADLOCK,     EDEADLK         },
 183         { -1,                   EIO             }
 184 };
 185
 186 static int
 187 nfs_cb_stat_to_errno(int stat)
 188 {
 189         int i;
 190         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 191                 if (nfs_cb_errtbl[i].stat == stat)
 192                         return nfs_cb_errtbl[i].errno;
 193         }
 194         /* If we cannot translate the error, the recovery routines should
 195         * handle it.
 196         * Note: remaining NFSv4 error codes have values > 10000, so should
 197         * not conflict with native Linux error codes.
 198         */
 199         return stat;
 200 }
 201
 202 /*
 203  * XDR encode
 204  */
 205
 206 static void
 207 encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
 208 {
 209         __be32 * p;
 210
 211         RESERVE_SPACE(16);
 212         WRITE32(0);            /* tag length is always 0 */
 213         WRITE32(hdr->minorversion);
 214         WRITE32(hdr->ident);
 215         hdr->nops_p = p;
 216         WRITE32(hdr->nops);
 217 }
 218
 219 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 220 {
 221         *hdr->nops_p = htonl(hdr->nops);
 222 }
 223
 224 static void
 225 encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
 226                 struct nfs4_cb_compound_hdr *hdr)
 227 {
 228         __be32 *p;
 229         int len = dp->dl_fh.fh_size;
 230
 231         RESERVE_SPACE(12+sizeof(dp->dl_stateid) + len);
 232         WRITE32(OP_CB_RECALL);
 233         WRITE32(dp->dl_stateid.si_generation);
 234         WRITEMEM(&dp->dl_stateid.si_opaque, sizeof(stateid_opaque_t));
 235         WRITE32(0); /* truncate optimization not implemented */
 236         WRITE32(len);
 237         WRITEMEM(&dp->dl_fh.fh_base, len);
 238         hdr->nops++;
 239 }
 240
 241 static void
 242 encode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *args,
 243                    struct nfs4_cb_compound_hdr *hdr)
 244 {
 245         __be32 *p;
 246
 247         if (hdr->minorversion == 0)
 248                 return;
 249
 250         RESERVE_SPACE(1 + NFS4_MAX_SESSIONID_LEN + 20);
 251
 252         WRITE32(OP_CB_SEQUENCE);
 253         WRITEMEM(args->cbs_clp->cl_sessionid.data, NFS4_MAX_SESSIONID_LEN);
 254         WRITE32(args->cbs_clp->cl_cb_seq_nr);
 255         WRITE32(0);             /* slotid, always 0 */
 256         WRITE32(0);             /* highest slotid always 0 */
 257         WRITE32(0);             /* cachethis always 0 */
 258         WRITE32(0); /* FIXME: support referring_call_lists */
 259         hdr->nops++;
 260 }
 261
 262 static int
 263 nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
 264 {
 265         struct xdr_stream xdrs, *xdr = &xdrs;
 266
 267         xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
 268         RESERVE_SPACE(0);
 269         return 0;
 270 }
 271
 272 static int
 273 nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p,
 274                 struct nfs4_rpc_args *rpc_args)
 275 {
 276         struct xdr_stream xdr;
 277         struct nfs4_delegation *args = rpc_args->args_op;
 278         struct nfs4_cb_compound_hdr hdr = {
 279                 .ident = args->dl_ident,
 280                 .minorversion = rpc_args->args_seq.cbs_minorversion,
 281         };
 282
 283         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
 284         encode_cb_compound_hdr(&xdr, &hdr);
 285         encode_cb_sequence(&xdr, &rpc_args->args_seq, &hdr);
 286         encode_cb_recall(&xdr, args, &hdr);
 287         encode_cb_nops(&hdr);
 288         return 0;
 289 }
 290
 291
 292 static int
 293 decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
 294         __be32 *p;
 295
 296         READ_BUF(8);
 297         READ32(hdr->status);
 298         READ32(hdr->taglen);
 299         READ_BUF(hdr->taglen + 4);
 300         hdr->tag = (char *)p;
 301         p += XDR_QUADLEN(hdr->taglen);
 302         READ32(hdr->nops);
 303         return 0;
 304 }
 305
 306 static int
 307 decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
 308 {
 309         __be32 *p;
 310         u32 op;
 311         int32_t nfserr;
 312
 313         READ_BUF(8);
 314         READ32(op);
 315         if (op != expected) {
 316                 dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
 317                          " operation %d but we issued a request for %d\n",
 318                          op, expected);
 319                 return -EIO;
 320         }
 321         READ32(nfserr);
 322         if (nfserr != NFS_OK)
 323                 return -nfs_cb_stat_to_errno(nfserr);
 324         return 0;
 325 }
 326
 327 /*
 328  * Our current back channel implmentation supports a single backchannel
 329  * with a single slot.
 330  */
 331 static int
 332 decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
 333                    struct rpc_rqst *rqstp)
 334 {
 335         struct nfs4_sessionid id;
 336         int status;
 337         u32 dummy;
 338         __be32 *p;
 339
 340         if (res->cbs_minorversion == 0)
 341                 return 0;
 342
 343         status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
 344         if (status)
 345                 return status;
 346
 347         /*
 348          * If the server returns different values for sessionID, slotID or
 349          * sequence number, the server is looney tunes.
 350          */
 351         status = -ESERVERFAULT;
 352
 353         READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
 354         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 355         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 356         if (memcmp(id.data, res->cbs_clp->cl_sessionid.data,
 357                    NFS4_MAX_SESSIONID_LEN)) {
 358                 dprintk("%s Invalid session id\n", __func__);
 359                 goto out;
 360         }
 361         READ32(dummy);
 362         if (dummy != res->cbs_clp->cl_cb_seq_nr) {
 363                 dprintk("%s Invalid sequence number\n", __func__);
 364                 goto out;
 365         }
 366         READ32(dummy);  /* slotid must be 0 */
 367         if (dummy != 0) {
 368                 dprintk("%s Invalid slotid\n", __func__);
 369                 goto out;
 370         }
 371         /* FIXME: process highest slotid and target highest slotid */
 372         status = 0;
 373 out:
 374         return status;
 375 }
 376
 377
 378 static int
 379 nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
 380 {
 381         return 0;
 382 }
 383
 384 static int
 385 nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p,
 386                 struct nfsd4_cb_sequence *seq)
 387 {
 388         struct xdr_stream xdr;
 389         struct nfs4_cb_compound_hdr hdr;
 390         int status;
 391
 392         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
 393         status = decode_cb_compound_hdr(&xdr, &hdr);
 394         if (status)
 395                 goto out;
 396         if (seq) {
 397                 status = decode_cb_sequence(&xdr, seq, rqstp);
 398                 if (status)
 399                         goto out;
 400         }
 401         status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
 402 out:
 403         return status;
 404 }
 405
 406 /*
 407  * RPC procedure tables
 408  */
 409 #define PROC(proc, call, argtype, restype)                              \
 410 [NFSPROC4_CLNT_##proc] = {                                              \
 411         .p_proc   = NFSPROC4_CB_##call,                                 \
 412         .p_encode = (kxdrproc_t) nfs4_xdr_##argtype,                    \
 413         .p_decode = (kxdrproc_t) nfs4_xdr_##restype,                    \
 414         .p_arglen = NFS4_##argtype##_sz,                                \
 415         .p_replen = NFS4_##restype##_sz,                                \
 416         .p_statidx = NFSPROC4_CB_##call,                                \
 417         .p_name   = #proc,                                              \
 418 }
 419
 420 static struct rpc_procinfo     nfs4_cb_procedures[] = {
 421     PROC(CB_NULL,      NULL,     enc_cb_null,     dec_cb_null),
 422     PROC(CB_RECALL,    COMPOUND,   enc_cb_recall,      dec_cb_recall),
 423 };
 424
 425 static struct rpc_version       nfs_cb_version4 = {
 426         .number                 = 1,
 427         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 428         .procs                  = nfs4_cb_procedures
 429 };
 430
 431 static struct rpc_version *     nfs_cb_version[] = {
 432         NULL,
 433         &nfs_cb_version4,
 434 };
 435
 436 static struct rpc_program cb_program;
 437
 438 static struct rpc_stat cb_stats = {
 439                 .program        = &cb_program
 440 };
 441
 442 #define NFS4_CALLBACK 0x40000000
 443 static struct rpc_program cb_program = {
 444                 .name           = "nfs4_cb",
 445                 .number         = NFS4_CALLBACK,
 446                 .nrvers         = ARRAY_SIZE(nfs_cb_version),
 447                 .version        = nfs_cb_version,
 448                 .stats          = &cb_stats,
 449                 .pipe_dir_name  = "/nfsd4_cb",
 450 };
 451
 452 static int max_cb_time(void)
 453 {
 454         return max(nfsd4_lease/10, (time_t)1) * HZ;
 455 }
 456
 457 /* Reference counting, callback cleanup, etc., all look racy as heck.
 458  * And why is cl_cb_set an atomic? */
 459
 460 int setup_callback_client(struct nfs4_client *clp)
 461 {
 462         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
 463         struct rpc_timeout      timeparms = {
 464                 .to_initval     = max_cb_time(),
 465                 .to_retries     = 0,
 466         };
 467         struct rpc_create_args args = {
 468                 .protocol       = XPRT_TRANSPORT_TCP,
 469                 .address        = (struct sockaddr *) &cb->cb_addr,
 470                 .addrsize       = cb->cb_addrlen,
 471                 .timeout        = &timeparms,
 472                 .program        = &cb_program,
 473                 .prognumber     = cb->cb_prog,
 474                 .version        = nfs_cb_version[1]->number,
 475                 .authflavor     = clp->cl_flavor,
 476                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 477                 .client_name    = clp->cl_principal,
 478         };
 479         struct rpc_clnt *client;
 480
 481         if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 482                 return -EINVAL;
 483         if (cb->cb_minorversion) {
 484                 args.bc_xprt = clp->cl_cb_conn.cb_xprt;
 485                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 486         }
 487         /* Create RPC client */
 488         client = rpc_create(&args);
 489         if (IS_ERR(client)) {
 490                 dprintk("NFSD: couldn't create callback client: %ld\n",
 491                         PTR_ERR(client));
 492                 return PTR_ERR(client);
 493         }
 494         clp->cl_cb_client = client;
 495         return 0;
 496
 497 }
 498
 499 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 500 {
 501         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 502                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 503 }
 504
 505 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 506 {
 507         struct nfs4_client *clp = calldata;
 508
 509         if (task->tk_status)
 510                 warn_no_callback_path(clp, task->tk_status);
 511         else
 512                 atomic_set(&clp->cl_cb_set, 1);
 513 }
 514
 515 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 516         .rpc_call_done = nfsd4_cb_probe_done,
 517 };
 518
 519 static struct rpc_cred *callback_cred;
 520
 521 int set_callback_cred(void)
 522 {
 523         if (callback_cred)
 524                 return 0;
 525         callback_cred = rpc_lookup_machine_cred();
 526         if (!callback_cred)
 527                 return -ENOMEM;
 528         return 0;
 529 }
 530
 531
 532 void do_probe_callback(struct nfs4_client *clp)
 533 {
 534         struct rpc_message msg = {
 535                 .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
 536                 .rpc_argp       = clp,
 537                 .rpc_cred       = callback_cred
 538         };
 539         int status;
 540
 541         status = rpc_call_async(clp->cl_cb_client, &msg,
 542                                 RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
 543                                 &nfsd4_cb_probe_ops, (void *)clp);
 544         if (status)
 545                 warn_no_callback_path(clp, status);
 546 }
 547
 548 /*
 549  * Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
 550  */
 551 void
 552 nfsd4_probe_callback(struct nfs4_client *clp)
 553 {
 554         int status;
 555
 556         BUG_ON(atomic_read(&clp->cl_cb_set));
 557
 558         status = setup_callback_client(clp);
 559         if (status) {
 560                 warn_no_callback_path(clp, status);
 561                 return;
 562         }
 563         do_probe_callback(clp);
 564 }
 565
 566 /*
 567  * There's currently a single callback channel slot.
 568  * If the slot is available, then mark it busy.  Otherwise, set the
 569  * thread for sleeping on the callback RPC wait queue.
 570  */
 571 static int nfsd41_cb_setup_sequence(struct nfs4_client *clp,
 572                 struct rpc_task *task)
 573 {
 574         struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
 575         u32 *ptr = (u32 *)clp->cl_sessionid.data;
 576         int status = 0;
 577
 578         dprintk("%s: %u:%u:%u:%u\n", __func__,
 579                 ptr[0], ptr[1], ptr[2], ptr[3]);
 580
 581         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 582                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 583                 dprintk("%s slot is busy\n", __func__);
 584                 status = -EAGAIN;
 585                 goto out;
 586         }
 587
 588         /*
 589          * We'll need the clp during XDR encoding and decoding,
 590          * and the sequence during decoding to verify the reply
 591          */
 592         args->args_seq.cbs_clp = clp;
 593         task->tk_msg.rpc_resp = &args->args_seq;
 594
 595 out:
 596         dprintk("%s status=%d\n", __func__, status);
 597         return status;
 598 }
 599
 600 /*
 601  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 602  * slots, and mark callback channel down on communication errors.
 603  */
 604 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 605 {
 606         struct nfs4_delegation *dp = calldata;
 607         struct nfs4_client *clp = dp->dl_client;
 608         struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
 609         u32 minorversion = clp->cl_cb_conn.cb_minorversion;
 610         int status = 0;
 611
 612         args->args_seq.cbs_minorversion = minorversion;
 613         if (minorversion) {
 614                 status = nfsd41_cb_setup_sequence(clp, task);
 615                 if (status) {
 616                         if (status != -EAGAIN) {
 617                                 /* terminate rpc task */
 618                                 task->tk_status = status;
 619                                 task->tk_action = NULL;
 620                         }
 621                         return;
 622                 }
 623         }
 624         rpc_call_start(task);
 625 }
 626
 627 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 628 {
 629         struct nfs4_delegation *dp = calldata;
 630         struct nfs4_client *clp = dp->dl_client;
 631
 632         dprintk("%s: minorversion=%d\n", __func__,
 633                 clp->cl_cb_conn.cb_minorversion);
 634
 635         if (clp->cl_cb_conn.cb_minorversion) {
 636                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 637                 ++clp->cl_cb_seq_nr;
 638                 clear_bit(0, &clp->cl_cb_slot_busy);
 639                 rpc_wake_up_next(&clp->cl_cb_waitq);
 640                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 641                         clp->cl_cb_seq_nr);
 642
 643                 /* We're done looking into the sequence information */
 644                 task->tk_msg.rpc_resp = NULL;
 645         }
 646 }
 647
 648 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 649 {
 650         struct nfs4_delegation *dp = calldata;
 651         struct nfs4_client *clp = dp->dl_client;
 652
 653         nfsd4_cb_done(task, calldata);
 654
 655         switch (task->tk_status) {
 656         case -EIO:
 657                 /* Network partition? */
 658                 atomic_set(&clp->cl_cb_set, 0);
 659                 warn_no_callback_path(clp, task->tk_status);
 660         case -EBADHANDLE:
 661         case -NFS4ERR_BAD_STATEID:
 662                 /* Race: client probably got cb_recall
 663                  * before open reply granting delegation */
 664                 break;
 665         default:
 666                 /* success, or error we can't handle */
 667                 return;
 668         }
 669         if (dp->dl_retries--) {
 670                 rpc_delay(task, 2*HZ);
 671                 task->tk_status = 0;
 672                 rpc_restart_call(task);
 673                 return;
 674         } else {
 675                 atomic_set(&clp->cl_cb_set, 0);
 676                 warn_no_callback_path(clp, task->tk_status);
 677         }
 678 }
 679
 680 static void nfsd4_cb_recall_release(void *calldata)
 681 {
 682         struct nfs4_delegation *dp = calldata;
 683
 684         nfs4_put_delegation(dp);
 685 }
 686
 687 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 688         .rpc_call_prepare = nfsd4_cb_prepare,
 689         .rpc_call_done = nfsd4_cb_recall_done,
 690         .rpc_release = nfsd4_cb_recall_release,
 691 };
 692
 693 static struct workqueue_struct *callback_wq;
 694
 695 int nfsd4_create_callback_queue(void)
 696 {
 697         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 698         if (!callback_wq)
 699                 return -ENOMEM;
 700         return 0;
 701 }
 702
 703 void nfsd4_destroy_callback_queue(void)
 704 {
 705         destroy_workqueue(callback_wq);
 706 }
 707
 708 void nfsd4_set_callback_client(struct nfs4_client *clp, struct rpc_clnt
 709 *new)
 710 {
 711         struct rpc_clnt *old = clp->cl_cb_client;
 712
 713         clp->cl_cb_client = new;
 714         /*
 715          * After this, any work that saw the old value of cl_cb_client will
 716          * be gone:
 717          */
 718         flush_workqueue(callback_wq);
 719         /* So we can safely shut it down: */
 720         if (old)
 721                 rpc_shutdown_client(old);
 722 }
 723
 724 /*
 725  * called with dp->dl_count inc'ed.
 726  */
 727 static void _nfsd4_cb_recall(struct nfs4_delegation *dp)
 728 {
 729         struct nfs4_client *clp = dp->dl_client;
 730         struct rpc_clnt *clnt = clp->cl_cb_client;
 731         struct nfs4_rpc_args *args = &dp->dl_recall.cb_args;
 732         struct rpc_message msg = {
 733                 .rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
 734                 .rpc_cred = callback_cred
 735         };
 736         int status;
 737
 738         if (clnt == NULL)
 739                 return; /* Client is shutting down; give up. */
 740
 741         args->args_op = dp;
 742         msg.rpc_argp = args;
 743         dp->dl_retries = 1;
 744         status = rpc_call_async(clnt, &msg, RPC_TASK_SOFT,
 745                                 &nfsd4_cb_recall_ops, dp);
 746         if (status)
 747                 nfs4_put_delegation(dp);
 748 }
 749
 750 void nfsd4_do_callback_rpc(struct work_struct *w)
 751 {
 752         /* XXX: for now, just send off delegation recall. */
 753         /* In future, generalize to handle any sort of callback. */
 754         struct nfsd4_callback *c = container_of(w, struct nfsd4_callback, cb_work);
 755         struct nfs4_delegation *dp = container_of(c, struct nfs4_delegation, dl_recall);
 756
 757         _nfsd4_cb_recall(dp);
 758 }
 759
 760
 761 void nfsd4_cb_recall(struct nfs4_delegation *dp)
 762 {
 763         queue_work(callback_wq, &dp->dl_recall.cb_work);
 764 }