SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 "nfsd.h"
  36 #include "state.h"
  37
  38 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  39
  40 #define NFSPROC4_CB_NULL 0
  41 #define NFSPROC4_CB_COMPOUND 1
  42 #define NFS4_STATEID_SIZE 16
  43
  44 /* Index of predefined Linux callback client operations */
  45
  46 enum {
  47         NFSPROC4_CLNT_CB_NULL = 0,
  48         NFSPROC4_CLNT_CB_RECALL,
  49         NFSPROC4_CLNT_CB_SEQUENCE,
  50 };
  51
  52 enum nfs_cb_opnum4 {
  53         OP_CB_RECALL            = 4,
  54         OP_CB_SEQUENCE          = 11,
  55 };
  56
  57 #define NFS4_MAXTAGLEN          20
  58
  59 #define NFS4_enc_cb_null_sz             0
  60 #define NFS4_dec_cb_null_sz             0
  61 #define cb_compound_enc_hdr_sz          4
  62 #define cb_compound_dec_hdr_sz          (3 + (NFS4_MAXTAGLEN >> 2))
  63 #define sessionid_sz                    (NFS4_MAX_SESSIONID_LEN >> 2)
  64 #define cb_sequence_enc_sz              (sessionid_sz + 4 +             \
  65                                         1 /* no referring calls list yet */)
  66 #define cb_sequence_dec_sz              (op_dec_sz + sessionid_sz + 4)
  67
  68 #define op_enc_sz                       1
  69 #define op_dec_sz                       2
  70 #define enc_nfs4_fh_sz                  (1 + (NFS4_FHSIZE >> 2))
  71 #define enc_stateid_sz                  (NFS4_STATEID_SIZE >> 2)
  72 #define NFS4_enc_cb_recall_sz           (cb_compound_enc_hdr_sz +       \
  73                                         cb_sequence_enc_sz +            \
  74                                         1 + enc_stateid_sz +            \
  75                                         enc_nfs4_fh_sz)
  76
  77 #define NFS4_dec_cb_recall_sz           (cb_compound_dec_hdr_sz  +      \
  78                                         cb_sequence_dec_sz +            \
  79                                         op_dec_sz)
  80
  81 /*
  82 * Generic encode routines from fs/nfs/nfs4xdr.c
  83 */
  84 static inline __be32 *
  85 xdr_writemem(__be32 *p, const void *ptr, int nbytes)
  86 {
  87         int tmp = XDR_QUADLEN(nbytes);
  88         if (!tmp)
  89                 return p;
  90         p[tmp-1] = 0;
  91         memcpy(p, ptr, nbytes);
  92         return p + tmp;
  93 }
  94
  95 #define WRITE32(n)               *p++ = htonl(n)
  96 #define WRITEMEM(ptr,nbytes)     do {                           \
  97         p = xdr_writemem(p, ptr, nbytes);                       \
  98 } while (0)
  99 #define RESERVE_SPACE(nbytes)   do {                            \
 100         p = xdr_reserve_space(xdr, nbytes);                     \
 101         if (!p) dprintk("NFSD: RESERVE_SPACE(%d) failed in function %s\n", (int) (nbytes), __func__); \
 102         BUG_ON(!p);                                             \
 103 } while (0)
 104
 105 /*
 106  * Generic decode routines from fs/nfs/nfs4xdr.c
 107  */
 108 #define DECODE_TAIL                             \
 109         status = 0;                             \
 110 out:                                            \
 111         return status;                          \
 112 xdr_error:                                      \
 113         dprintk("NFSD: xdr error! (%s:%d)\n", __FILE__, __LINE__); \
 114         status = -EIO;                          \
 115         goto out
 116
 117 #define READ32(x)         (x) = ntohl(*p++)
 118 #define READ64(x)         do {                  \
 119         (x) = (u64)ntohl(*p++) << 32;           \
 120         (x) |= ntohl(*p++);                     \
 121 } while (0)
 122 #define READTIME(x)       do {                  \
 123         p++;                                    \
 124         (x.tv_sec) = ntohl(*p++);               \
 125         (x.tv_nsec) = ntohl(*p++);              \
 126 } while (0)
 127 #define READ_BUF(nbytes)  do { \
 128         p = xdr_inline_decode(xdr, nbytes); \
 129         if (!p) { \
 130                 dprintk("NFSD: %s: reply buffer overflowed in line %d.\n", \
 131                         __func__, __LINE__); \
 132                 return -EIO; \
 133         } \
 134 } while (0)
 135
 136 struct nfs4_cb_compound_hdr {
 137         /* args */
 138         u32             ident;  /* minorversion 0 only */
 139         u32             nops;
 140         __be32          *nops_p;
 141         u32             minorversion;
 142         /* res */
 143         int             status;
 144         u32             taglen;
 145         char            *tag;
 146 };
 147
 148 static struct {
 149 int stat;
 150 int errno;
 151 } nfs_cb_errtbl[] = {
 152         { NFS4_OK,              0               },
 153         { NFS4ERR_PERM,         EPERM           },
 154         { NFS4ERR_NOENT,        ENOENT          },
 155         { NFS4ERR_IO,           EIO             },
 156         { NFS4ERR_NXIO,         ENXIO           },
 157         { NFS4ERR_ACCESS,       EACCES          },
 158         { NFS4ERR_EXIST,        EEXIST          },
 159         { NFS4ERR_XDEV,         EXDEV           },
 160         { NFS4ERR_NOTDIR,       ENOTDIR         },
 161         { NFS4ERR_ISDIR,        EISDIR          },
 162         { NFS4ERR_INVAL,        EINVAL          },
 163         { NFS4ERR_FBIG,         EFBIG           },
 164         { NFS4ERR_NOSPC,        ENOSPC          },
 165         { NFS4ERR_ROFS,         EROFS           },
 166         { NFS4ERR_MLINK,        EMLINK          },
 167         { NFS4ERR_NAMETOOLONG,  ENAMETOOLONG    },
 168         { NFS4ERR_NOTEMPTY,     ENOTEMPTY       },
 169         { NFS4ERR_DQUOT,        EDQUOT          },
 170         { NFS4ERR_STALE,        ESTALE          },
 171         { NFS4ERR_BADHANDLE,    EBADHANDLE      },
 172         { NFS4ERR_BAD_COOKIE,   EBADCOOKIE      },
 173         { NFS4ERR_NOTSUPP,      ENOTSUPP        },
 174         { NFS4ERR_TOOSMALL,     ETOOSMALL       },
 175         { NFS4ERR_SERVERFAULT,  ESERVERFAULT    },
 176         { NFS4ERR_BADTYPE,      EBADTYPE        },
 177         { NFS4ERR_LOCKED,       EAGAIN          },
 178         { NFS4ERR_RESOURCE,     EREMOTEIO       },
 179         { NFS4ERR_SYMLINK,      ELOOP           },
 180         { NFS4ERR_OP_ILLEGAL,   EOPNOTSUPP      },
 181         { NFS4ERR_DEADLOCK,     EDEADLK         },
 182         { -1,                   EIO             }
 183 };
 184
 185 static int
 186 nfs_cb_stat_to_errno(int stat)
 187 {
 188         int i;
 189         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 190                 if (nfs_cb_errtbl[i].stat == stat)
 191                         return nfs_cb_errtbl[i].errno;
 192         }
 193         /* If we cannot translate the error, the recovery routines should
 194         * handle it.
 195         * Note: remaining NFSv4 error codes have values > 10000, so should
 196         * not conflict with native Linux error codes.
 197         */
 198         return stat;
 199 }
 200
 201 /*
 202  * XDR encode
 203  */
 204
 205 static void
 206 encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
 207 {
 208         __be32 * p;
 209
 210         RESERVE_SPACE(16);
 211         WRITE32(0);            /* tag length is always 0 */
 212         WRITE32(hdr->minorversion);
 213         WRITE32(hdr->ident);
 214         hdr->nops_p = p;
 215         WRITE32(hdr->nops);
 216 }
 217
 218 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 219 {
 220         *hdr->nops_p = htonl(hdr->nops);
 221 }
 222
 223 static void
 224 encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
 225                 struct nfs4_cb_compound_hdr *hdr)
 226 {
 227         __be32 *p;
 228         int len = dp->dl_fh.fh_size;
 229
 230         RESERVE_SPACE(12+sizeof(dp->dl_stateid) + len);
 231         WRITE32(OP_CB_RECALL);
 232         WRITE32(dp->dl_stateid.si_generation);
 233         WRITEMEM(&dp->dl_stateid.si_opaque, sizeof(stateid_opaque_t));
 234         WRITE32(0); /* truncate optimization not implemented */
 235         WRITE32(len);
 236         WRITEMEM(&dp->dl_fh.fh_base, len);
 237         hdr->nops++;
 238 }
 239
 240 static void
 241 encode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *args,
 242                    struct nfs4_cb_compound_hdr *hdr)
 243 {
 244         __be32 *p;
 245
 246         if (hdr->minorversion == 0)
 247                 return;
 248
 249         RESERVE_SPACE(1 + NFS4_MAX_SESSIONID_LEN + 20);
 250
 251         WRITE32(OP_CB_SEQUENCE);
 252         WRITEMEM(args->cbs_clp->cl_sessionid.data, NFS4_MAX_SESSIONID_LEN);
 253         WRITE32(args->cbs_clp->cl_cb_seq_nr);
 254         WRITE32(0);             /* slotid, always 0 */
 255         WRITE32(0);             /* highest slotid always 0 */
 256         WRITE32(0);             /* cachethis always 0 */
 257         WRITE32(0); /* FIXME: support referring_call_lists */
 258         hdr->nops++;
 259 }
 260
 261 static int
 262 nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
 263 {
 264         struct xdr_stream xdrs, *xdr = &xdrs;
 265
 266         xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
 267         RESERVE_SPACE(0);
 268         return 0;
 269 }
 270
 271 static int
 272 nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p,
 273                 struct nfs4_rpc_args *rpc_args)
 274 {
 275         struct xdr_stream xdr;
 276         struct nfs4_delegation *args = rpc_args->args_op;
 277         struct nfs4_cb_compound_hdr hdr = {
 278                 .ident = args->dl_ident,
 279                 .minorversion = rpc_args->args_seq.cbs_minorversion,
 280         };
 281
 282         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
 283         encode_cb_compound_hdr(&xdr, &hdr);
 284         encode_cb_sequence(&xdr, &rpc_args->args_seq, &hdr);
 285         encode_cb_recall(&xdr, args, &hdr);
 286         encode_cb_nops(&hdr);
 287         return 0;
 288 }
 289
 290
 291 static int
 292 decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
 293         __be32 *p;
 294
 295         READ_BUF(8);
 296         READ32(hdr->status);
 297         READ32(hdr->taglen);
 298         READ_BUF(hdr->taglen + 4);
 299         hdr->tag = (char *)p;
 300         p += XDR_QUADLEN(hdr->taglen);
 301         READ32(hdr->nops);
 302         return 0;
 303 }
 304
 305 static int
 306 decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
 307 {
 308         __be32 *p;
 309         u32 op;
 310         int32_t nfserr;
 311
 312         READ_BUF(8);
 313         READ32(op);
 314         if (op != expected) {
 315                 dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
 316                          " operation %d but we issued a request for %d\n",
 317                          op, expected);
 318                 return -EIO;
 319         }
 320         READ32(nfserr);
 321         if (nfserr != NFS_OK)
 322                 return -nfs_cb_stat_to_errno(nfserr);
 323         return 0;
 324 }
 325
 326 /*
 327  * Our current back channel implmentation supports a single backchannel
 328  * with a single slot.
 329  */
 330 static int
 331 decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
 332                    struct rpc_rqst *rqstp)
 333 {
 334         struct nfs4_sessionid id;
 335         int status;
 336         u32 dummy;
 337         __be32 *p;
 338
 339         if (res->cbs_minorversion == 0)
 340                 return 0;
 341
 342         status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
 343         if (status)
 344                 return status;
 345
 346         /*
 347          * If the server returns different values for sessionID, slotID or
 348          * sequence number, the server is looney tunes.
 349          */
 350         status = -ESERVERFAULT;
 351
 352         READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
 353         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 354         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 355         if (memcmp(id.data, res->cbs_clp->cl_sessionid.data,
 356                    NFS4_MAX_SESSIONID_LEN)) {
 357                 dprintk("%s Invalid session id\n", __func__);
 358                 goto out;
 359         }
 360         READ32(dummy);
 361         if (dummy != res->cbs_clp->cl_cb_seq_nr) {
 362                 dprintk("%s Invalid sequence number\n", __func__);
 363                 goto out;
 364         }
 365         READ32(dummy);  /* slotid must be 0 */
 366         if (dummy != 0) {
 367                 dprintk("%s Invalid slotid\n", __func__);
 368                 goto out;
 369         }
 370         /* FIXME: process highest slotid and target highest slotid */
 371         status = 0;
 372 out:
 373         return status;
 374 }
 375
 376
 377 static int
 378 nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
 379 {
 380         return 0;
 381 }
 382
 383 static int
 384 nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p,
 385                 struct nfsd4_cb_sequence *seq)
 386 {
 387         struct xdr_stream xdr;
 388         struct nfs4_cb_compound_hdr hdr;
 389         int status;
 390
 391         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
 392         status = decode_cb_compound_hdr(&xdr, &hdr);
 393         if (status)
 394                 goto out;
 395         if (seq) {
 396                 status = decode_cb_sequence(&xdr, seq, rqstp);
 397                 if (status)
 398                         goto out;
 399         }
 400         status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
 401 out:
 402         return status;
 403 }
 404
 405 /*
 406  * RPC procedure tables
 407  */
 408 #define PROC(proc, call, argtype, restype)                              \
 409 [NFSPROC4_CLNT_##proc] = {                                              \
 410         .p_proc   = NFSPROC4_CB_##call,                                 \
 411         .p_encode = (kxdrproc_t) nfs4_xdr_##argtype,                    \
 412         .p_decode = (kxdrproc_t) nfs4_xdr_##restype,                    \
 413         .p_arglen = NFS4_##argtype##_sz,                                \
 414         .p_replen = NFS4_##restype##_sz,                                \
 415         .p_statidx = NFSPROC4_CB_##call,                                \
 416         .p_name   = #proc,                                              \
 417 }
 418
 419 static struct rpc_procinfo     nfs4_cb_procedures[] = {
 420     PROC(CB_NULL,      NULL,     enc_cb_null,     dec_cb_null),
 421     PROC(CB_RECALL,    COMPOUND,   enc_cb_recall,      dec_cb_recall),
 422 };
 423
 424 static struct rpc_version       nfs_cb_version4 = {
 425         .number                 = 1,
 426         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 427         .procs                  = nfs4_cb_procedures
 428 };
 429
 430 static struct rpc_version *     nfs_cb_version[] = {
 431         NULL,
 432         &nfs_cb_version4,
 433 };
 434
 435 static struct rpc_program cb_program;
 436
 437 static struct rpc_stat cb_stats = {
 438                 .program        = &cb_program
 439 };
 440
 441 #define NFS4_CALLBACK 0x40000000
 442 static struct rpc_program cb_program = {
 443                 .name           = "nfs4_cb",
 444                 .number         = NFS4_CALLBACK,
 445                 .nrvers         = ARRAY_SIZE(nfs_cb_version),
 446                 .version        = nfs_cb_version,
 447                 .stats          = &cb_stats,
 448                 .pipe_dir_name  = "/nfsd4_cb",
 449 };
 450
 451 static int max_cb_time(void)
 452 {
 453         return max(nfsd4_lease/10, (time_t)1) * HZ;
 454 }
 455
 456 /* Reference counting, callback cleanup, etc., all look racy as heck.
 457  * And why is cb_set an atomic? */
 458
 459 int setup_callback_client(struct nfs4_client *clp)
 460 {
 461         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
 462         struct rpc_timeout      timeparms = {
 463                 .to_initval     = max_cb_time(),
 464                 .to_retries     = 0,
 465         };
 466         struct rpc_create_args args = {
 467                 .protocol       = XPRT_TRANSPORT_TCP,
 468                 .address        = (struct sockaddr *) &cb->cb_addr,
 469                 .addrsize       = cb->cb_addrlen,
 470                 .timeout        = &timeparms,
 471                 .program        = &cb_program,
 472                 .prognumber     = cb->cb_prog,
 473                 .version        = nfs_cb_version[1]->number,
 474                 .authflavor     = clp->cl_flavor,
 475                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 476                 .client_name    = clp->cl_principal,
 477         };
 478         struct rpc_clnt *client;
 479
 480         if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 481                 return -EINVAL;
 482         if (cb->cb_minorversion) {
 483                 args.bc_xprt = clp->cl_cb_xprt;
 484                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 485         }
 486         /* Create RPC client */
 487         client = rpc_create(&args);
 488         if (IS_ERR(client)) {
 489                 dprintk("NFSD: couldn't create callback client: %ld\n",
 490                         PTR_ERR(client));
 491                 return PTR_ERR(client);
 492         }
 493         cb->cb_client = client;
 494         return 0;
 495
 496 }
 497
 498 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 499 {
 500         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 501                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 502 }
 503
 504 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 505 {
 506         struct nfs4_client *clp = calldata;
 507
 508         if (task->tk_status)
 509                 warn_no_callback_path(clp, task->tk_status);
 510         else
 511                 atomic_set(&clp->cl_cb_conn.cb_set, 1);
 512         put_nfs4_client(clp);
 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 nfs4_cb_conn *cb = &clp->cl_cb_conn;
 535         struct rpc_message msg = {
 536                 .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
 537                 .rpc_argp       = clp,
 538                 .rpc_cred       = callback_cred
 539         };
 540         int status;
 541
 542         status = rpc_call_async(cb->cb_client, &msg,
 543                                 RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
 544                                 &nfsd4_cb_probe_ops, (void *)clp);
 545         if (status) {
 546                 warn_no_callback_path(clp, status);
 547                 put_nfs4_client(clp);
 548         }
 549 }
 550
 551 /*
 552  * Set up the callback client and put a NFSPROC4_CB_NULL on the wire...
 553  */
 554 void
 555 nfsd4_probe_callback(struct nfs4_client *clp)
 556 {
 557         int status;
 558
 559         BUG_ON(atomic_read(&clp->cl_cb_conn.cb_set));
 560
 561         status = setup_callback_client(clp);
 562         if (status) {
 563                 warn_no_callback_path(clp, status);
 564                 return;
 565         }
 566
 567         /* the task holds a reference to the nfs4_client struct */
 568         atomic_inc(&clp->cl_count);
 569
 570         do_probe_callback(clp);
 571 }
 572
 573 /*
 574  * There's currently a single callback channel slot.
 575  * If the slot is available, then mark it busy.  Otherwise, set the
 576  * thread for sleeping on the callback RPC wait queue.
 577  */
 578 static int nfsd41_cb_setup_sequence(struct nfs4_client *clp,
 579                 struct rpc_task *task)
 580 {
 581         struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
 582         u32 *ptr = (u32 *)clp->cl_sessionid.data;
 583         int status = 0;
 584
 585         dprintk("%s: %u:%u:%u:%u\n", __func__,
 586                 ptr[0], ptr[1], ptr[2], ptr[3]);
 587
 588         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 589                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 590                 dprintk("%s slot is busy\n", __func__);
 591                 status = -EAGAIN;
 592                 goto out;
 593         }
 594
 595         /*
 596          * We'll need the clp during XDR encoding and decoding,
 597          * and the sequence during decoding to verify the reply
 598          */
 599         args->args_seq.cbs_clp = clp;
 600         task->tk_msg.rpc_resp = &args->args_seq;
 601
 602 out:
 603         dprintk("%s status=%d\n", __func__, status);
 604         return status;
 605 }
 606
 607 /*
 608  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 609  * slots, and mark callback channel down on communication errors.
 610  */
 611 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 612 {
 613         struct nfs4_delegation *dp = calldata;
 614         struct nfs4_client *clp = dp->dl_client;
 615         struct nfs4_rpc_args *args = task->tk_msg.rpc_argp;
 616         u32 minorversion = clp->cl_cb_conn.cb_minorversion;
 617         int status = 0;
 618
 619         args->args_seq.cbs_minorversion = minorversion;
 620         if (minorversion) {
 621                 status = nfsd41_cb_setup_sequence(clp, task);
 622                 if (status) {
 623                         if (status != -EAGAIN) {
 624                                 /* terminate rpc task */
 625                                 task->tk_status = status;
 626                                 task->tk_action = NULL;
 627                         }
 628                         return;
 629                 }
 630         }
 631         rpc_call_start(task);
 632 }
 633
 634 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 635 {
 636         struct nfs4_delegation *dp = calldata;
 637         struct nfs4_client *clp = dp->dl_client;
 638
 639         dprintk("%s: minorversion=%d\n", __func__,
 640                 clp->cl_cb_conn.cb_minorversion);
 641
 642         if (clp->cl_cb_conn.cb_minorversion) {
 643                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 644                 ++clp->cl_cb_seq_nr;
 645                 clear_bit(0, &clp->cl_cb_slot_busy);
 646                 rpc_wake_up_next(&clp->cl_cb_waitq);
 647                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 648                         clp->cl_cb_seq_nr);
 649
 650                 /* We're done looking into the sequence information */
 651                 task->tk_msg.rpc_resp = NULL;
 652         }
 653 }
 654
 655 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 656 {
 657         struct nfs4_delegation *dp = calldata;
 658         struct nfs4_client *clp = dp->dl_client;
 659
 660         nfsd4_cb_done(task, calldata);
 661
 662         switch (task->tk_status) {
 663         case -EIO:
 664                 /* Network partition? */
 665                 atomic_set(&clp->cl_cb_conn.cb_set, 0);
 666                 warn_no_callback_path(clp, task->tk_status);
 667         case -EBADHANDLE:
 668         case -NFS4ERR_BAD_STATEID:
 669                 /* Race: client probably got cb_recall
 670                  * before open reply granting delegation */
 671                 break;
 672         default:
 673                 /* success, or error we can't handle */
 674                 return;
 675         }
 676         if (dp->dl_retries--) {
 677                 rpc_delay(task, 2*HZ);
 678                 task->tk_status = 0;
 679                 rpc_restart_call(task);
 680                 return;
 681         } else {
 682                 atomic_set(&clp->cl_cb_conn.cb_set, 0);
 683                 warn_no_callback_path(clp, task->tk_status);
 684         }
 685 }
 686
 687 static void nfsd4_cb_recall_release(void *calldata)
 688 {
 689         struct nfs4_delegation *dp = calldata;
 690         struct nfs4_client *clp = dp->dl_client;
 691
 692         nfs4_put_delegation(dp);
 693         put_nfs4_client(clp);
 694 }
 695
 696 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 697         .rpc_call_prepare = nfsd4_cb_prepare,
 698         .rpc_call_done = nfsd4_cb_recall_done,
 699         .rpc_release = nfsd4_cb_recall_release,
 700 };
 701
 702 /*
 703  * called with dp->dl_count inc'ed.
 704  */
 705 void
 706 nfsd4_cb_recall(struct nfs4_delegation *dp)
 707 {
 708         struct nfs4_client *clp = dp->dl_client;
 709         struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
 710         struct nfs4_rpc_args *args = &dp->dl_recall.cb_args;
 711         struct rpc_message msg = {
 712                 .rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
 713                 .rpc_cred = callback_cred
 714         };
 715         int status;
 716
 717         args->args_op = dp;
 718         msg.rpc_argp = args;
 719         dp->dl_retries = 1;
 720         status = rpc_call_async(clnt, &msg, RPC_TASK_SOFT,
 721                                 &nfsd4_cb_recall_ops, dp);
 722         if (status) {
 723                 put_nfs4_client(clp);
 724                 nfs4_put_delegation(dp);
 725         }
 726 }