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 <linux/slab.h>
  37 #include "nfsd.h"
  38 #include "state.h"
  39
  40 #define NFSDDBG_FACILITY                NFSDDBG_PROC
  41
  42 #define NFSPROC4_CB_NULL 0
  43 #define NFSPROC4_CB_COMPOUND 1
  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 };
 146
 147 static struct {
 148 int stat;
 149 int errno;
 150 } nfs_cb_errtbl[] = {
 151         { NFS4_OK,              0               },
 152         { NFS4ERR_PERM,         EPERM           },
 153         { NFS4ERR_NOENT,        ENOENT          },
 154         { NFS4ERR_IO,           EIO             },
 155         { NFS4ERR_NXIO,         ENXIO           },
 156         { NFS4ERR_ACCESS,       EACCES          },
 157         { NFS4ERR_EXIST,        EEXIST          },
 158         { NFS4ERR_XDEV,         EXDEV           },
 159         { NFS4ERR_NOTDIR,       ENOTDIR         },
 160         { NFS4ERR_ISDIR,        EISDIR          },
 161         { NFS4ERR_INVAL,        EINVAL          },
 162         { NFS4ERR_FBIG,         EFBIG           },
 163         { NFS4ERR_NOSPC,        ENOSPC          },
 164         { NFS4ERR_ROFS,         EROFS           },
 165         { NFS4ERR_MLINK,        EMLINK          },
 166         { NFS4ERR_NAMETOOLONG,  ENAMETOOLONG    },
 167         { NFS4ERR_NOTEMPTY,     ENOTEMPTY       },
 168         { NFS4ERR_DQUOT,        EDQUOT          },
 169         { NFS4ERR_STALE,        ESTALE          },
 170         { NFS4ERR_BADHANDLE,    EBADHANDLE      },
 171         { NFS4ERR_BAD_COOKIE,   EBADCOOKIE      },
 172         { NFS4ERR_NOTSUPP,      ENOTSUPP        },
 173         { NFS4ERR_TOOSMALL,     ETOOSMALL       },
 174         { NFS4ERR_SERVERFAULT,  ESERVERFAULT    },
 175         { NFS4ERR_BADTYPE,      EBADTYPE        },
 176         { NFS4ERR_LOCKED,       EAGAIN          },
 177         { NFS4ERR_RESOURCE,     EREMOTEIO       },
 178         { NFS4ERR_SYMLINK,      ELOOP           },
 179         { NFS4ERR_OP_ILLEGAL,   EOPNOTSUPP      },
 180         { NFS4ERR_DEADLOCK,     EDEADLK         },
 181         { -1,                   EIO             }
 182 };
 183
 184 static int
 185 nfs_cb_stat_to_errno(int stat)
 186 {
 187         int i;
 188         for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
 189                 if (nfs_cb_errtbl[i].stat == stat)
 190                         return nfs_cb_errtbl[i].errno;
 191         }
 192         /* If we cannot translate the error, the recovery routines should
 193         * handle it.
 194         * Note: remaining NFSv4 error codes have values > 10000, so should
 195         * not conflict with native Linux error codes.
 196         */
 197         return stat;
 198 }
 199
 200 /*
 201  * XDR encode
 202  */
 203
 204 static void
 205 encode_stateid(struct xdr_stream *xdr, stateid_t *sid)
 206 {
 207         __be32 *p;
 208
 209         RESERVE_SPACE(sizeof(stateid_t));
 210         WRITE32(sid->si_generation);
 211         WRITEMEM(&sid->si_opaque, sizeof(stateid_opaque_t));
 212 }
 213
 214 static void
 215 encode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr)
 216 {
 217         __be32 * p;
 218
 219         RESERVE_SPACE(16);
 220         WRITE32(0);            /* tag length is always 0 */
 221         WRITE32(hdr->minorversion);
 222         WRITE32(hdr->ident);
 223         hdr->nops_p = p;
 224         WRITE32(hdr->nops);
 225 }
 226
 227 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
 228 {
 229         *hdr->nops_p = htonl(hdr->nops);
 230 }
 231
 232 static void
 233 encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
 234                 struct nfs4_cb_compound_hdr *hdr)
 235 {
 236         __be32 *p;
 237         int len = dp->dl_fh.fh_size;
 238
 239         RESERVE_SPACE(4);
 240         WRITE32(OP_CB_RECALL);
 241         encode_stateid(xdr, &dp->dl_stateid);
 242         RESERVE_SPACE(8 + (XDR_QUADLEN(len) << 2));
 243         WRITE32(0); /* truncate optimization not implemented */
 244         WRITE32(len);
 245         WRITEMEM(&dp->dl_fh.fh_base, len);
 246         hdr->nops++;
 247 }
 248
 249 static void
 250 encode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_callback *cb,
 251                    struct nfs4_cb_compound_hdr *hdr)
 252 {
 253         __be32 *p;
 254         struct nfsd4_session *ses = cb->cb_clp->cl_cb_session;
 255
 256         if (hdr->minorversion == 0)
 257                 return;
 258
 259         RESERVE_SPACE(1 + NFS4_MAX_SESSIONID_LEN + 20);
 260
 261         WRITE32(OP_CB_SEQUENCE);
 262         WRITEMEM(ses->se_sessionid.data, NFS4_MAX_SESSIONID_LEN);
 263         WRITE32(ses->se_cb_seq_nr);
 264         WRITE32(0);             /* slotid, always 0 */
 265         WRITE32(0);             /* highest slotid always 0 */
 266         WRITE32(0);             /* cachethis always 0 */
 267         WRITE32(0); /* FIXME: support referring_call_lists */
 268         hdr->nops++;
 269 }
 270
 271 static int
 272 nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
 273 {
 274         struct xdr_stream xdrs, *xdr = &xdrs;
 275
 276         xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
 277         RESERVE_SPACE(0);
 278         return 0;
 279 }
 280
 281 static int
 282 nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p,
 283                 struct nfsd4_callback *cb)
 284 {
 285         struct xdr_stream xdr;
 286         struct nfs4_delegation *args = cb->cb_op;
 287         struct nfs4_cb_compound_hdr hdr = {
 288                 .ident = cb->cb_clp->cl_cb_ident,
 289                 .minorversion = cb->cb_minorversion,
 290         };
 291
 292         xdr_init_encode(&xdr, &req->rq_snd_buf, p);
 293         encode_cb_compound_hdr(&xdr, &hdr);
 294         encode_cb_sequence(&xdr, cb, &hdr);
 295         encode_cb_recall(&xdr, args, &hdr);
 296         encode_cb_nops(&hdr);
 297         return 0;
 298 }
 299
 300
 301 static int
 302 decode_cb_compound_hdr(struct xdr_stream *xdr, struct nfs4_cb_compound_hdr *hdr){
 303         __be32 *p;
 304         u32 taglen;
 305
 306         READ_BUF(8);
 307         READ32(hdr->status);
 308         /* We've got no use for the tag; ignore it: */
 309         READ32(taglen);
 310         READ_BUF(taglen + 4);
 311         p += XDR_QUADLEN(taglen);
 312         READ32(hdr->nops);
 313         return 0;
 314 }
 315
 316 static int
 317 decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
 318 {
 319         __be32 *p;
 320         u32 op;
 321         int32_t nfserr;
 322
 323         READ_BUF(8);
 324         READ32(op);
 325         if (op != expected) {
 326                 dprintk("NFSD: decode_cb_op_hdr: Callback server returned "
 327                          " operation %d but we issued a request for %d\n",
 328                          op, expected);
 329                 return -EIO;
 330         }
 331         READ32(nfserr);
 332         if (nfserr != NFS_OK)
 333                 return -nfs_cb_stat_to_errno(nfserr);
 334         return 0;
 335 }
 336
 337 /*
 338  * Our current back channel implmentation supports a single backchannel
 339  * with a single slot.
 340  */
 341 static int
 342 decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_callback *cb,
 343                    struct rpc_rqst *rqstp)
 344 {
 345         struct nfsd4_session *ses = cb->cb_clp->cl_cb_session;
 346         struct nfs4_sessionid id;
 347         int status;
 348         u32 dummy;
 349         __be32 *p;
 350
 351         if (cb->cb_minorversion == 0)
 352                 return 0;
 353
 354         status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
 355         if (status)
 356                 return status;
 357
 358         /*
 359          * If the server returns different values for sessionID, slotID or
 360          * sequence number, the server is looney tunes.
 361          */
 362         status = -ESERVERFAULT;
 363
 364         READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
 365         memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
 366         p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
 367         if (memcmp(id.data, ses->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 368                 dprintk("%s Invalid session id\n", __func__);
 369                 goto out;
 370         }
 371         READ32(dummy);
 372         if (dummy != ses->se_cb_seq_nr) {
 373                 dprintk("%s Invalid sequence number\n", __func__);
 374                 goto out;
 375         }
 376         READ32(dummy);  /* slotid must be 0 */
 377         if (dummy != 0) {
 378                 dprintk("%s Invalid slotid\n", __func__);
 379                 goto out;
 380         }
 381         /* FIXME: process highest slotid and target highest slotid */
 382         status = 0;
 383 out:
 384         return status;
 385 }
 386
 387
 388 static int
 389 nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
 390 {
 391         return 0;
 392 }
 393
 394 static int
 395 nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, __be32 *p,
 396                 struct nfsd4_callback *cb)
 397 {
 398         struct xdr_stream xdr;
 399         struct nfs4_cb_compound_hdr hdr;
 400         int status;
 401
 402         xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
 403         status = decode_cb_compound_hdr(&xdr, &hdr);
 404         if (status)
 405                 goto out;
 406         if (cb) {
 407                 status = decode_cb_sequence(&xdr, cb, rqstp);
 408                 if (status)
 409                         goto out;
 410         }
 411         status = decode_cb_op_hdr(&xdr, OP_CB_RECALL);
 412 out:
 413         return status;
 414 }
 415
 416 /*
 417  * RPC procedure tables
 418  */
 419 #define PROC(proc, call, argtype, restype)                              \
 420 [NFSPROC4_CLNT_##proc] = {                                              \
 421         .p_proc   = NFSPROC4_CB_##call,                                 \
 422         .p_encode = (kxdrproc_t) nfs4_xdr_##argtype,                    \
 423         .p_decode = (kxdrproc_t) nfs4_xdr_##restype,                    \
 424         .p_arglen = NFS4_##argtype##_sz,                                \
 425         .p_replen = NFS4_##restype##_sz,                                \
 426         .p_statidx = NFSPROC4_CB_##call,                                \
 427         .p_name   = #proc,                                              \
 428 }
 429
 430 static struct rpc_procinfo     nfs4_cb_procedures[] = {
 431     PROC(CB_NULL,      NULL,     enc_cb_null,     dec_cb_null),
 432     PROC(CB_RECALL,    COMPOUND,   enc_cb_recall,      dec_cb_recall),
 433 };
 434
 435 static struct rpc_version       nfs_cb_version4 = {
 436 /*
 437  * Note on the callback rpc program version number: despite language in rfc
 438  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
 439  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
 440  * in practice that appears to be what implementations use.  The section
 441  * 18.36.3 language is expected to be fixed in an erratum.
 442  */
 443         .number                 = 1,
 444         .nrprocs                = ARRAY_SIZE(nfs4_cb_procedures),
 445         .procs                  = nfs4_cb_procedures
 446 };
 447
 448 static struct rpc_version *     nfs_cb_version[] = {
 449         &nfs_cb_version4,
 450 };
 451
 452 static struct rpc_program cb_program;
 453
 454 static struct rpc_stat cb_stats = {
 455                 .program        = &cb_program
 456 };
 457
 458 #define NFS4_CALLBACK 0x40000000
 459 static struct rpc_program cb_program = {
 460                 .name           = "nfs4_cb",
 461                 .number         = NFS4_CALLBACK,
 462                 .nrvers         = ARRAY_SIZE(nfs_cb_version),
 463                 .version        = nfs_cb_version,
 464                 .stats          = &cb_stats,
 465                 .pipe_dir_name  = "/nfsd4_cb",
 466 };
 467
 468 static int max_cb_time(void)
 469 {
 470         return max(nfsd4_lease/10, (time_t)1) * HZ;
 471 }
 472
 473
 474 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
 475 {
 476         struct rpc_timeout      timeparms = {
 477                 .to_initval     = max_cb_time(),
 478                 .to_retries     = 0,
 479         };
 480         struct rpc_create_args args = {
 481                 .net            = &init_net,
 482                 .address        = (struct sockaddr *) &conn->cb_addr,
 483                 .addrsize       = conn->cb_addrlen,
 484                 .saddress       = (struct sockaddr *) &conn->cb_saddr,
 485                 .timeout        = &timeparms,
 486                 .program        = &cb_program,
 487                 .version        = 0,
 488                 .authflavor     = clp->cl_flavor,
 489                 .flags          = (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
 490         };
 491         struct rpc_clnt *client;
 492
 493         if (clp->cl_minorversion == 0) {
 494                 if (!clp->cl_principal && (clp->cl_flavor >= RPC_AUTH_GSS_KRB5))
 495                         return -EINVAL;
 496                 args.client_name = clp->cl_principal;
 497                 args.prognumber = conn->cb_prog,
 498                 args.protocol = XPRT_TRANSPORT_TCP;
 499                 clp->cl_cb_ident = conn->cb_ident;
 500         } else {
 501                 if (!conn->cb_xprt)
 502                         return -EINVAL;
 503                 clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
 504                 clp->cl_cb_session = ses;
 505                 args.bc_xprt = conn->cb_xprt;
 506                 args.prognumber = clp->cl_cb_session->se_cb_prog;
 507                 args.protocol = XPRT_TRANSPORT_BC_TCP;
 508         }
 509         /* Create RPC client */
 510         client = rpc_create(&args);
 511         if (IS_ERR(client)) {
 512                 dprintk("NFSD: couldn't create callback client: %ld\n",
 513                         PTR_ERR(client));
 514                 return PTR_ERR(client);
 515         }
 516         clp->cl_cb_client = client;
 517         return 0;
 518
 519 }
 520
 521 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
 522 {
 523         dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
 524                 (int)clp->cl_name.len, clp->cl_name.data, reason);
 525 }
 526
 527 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
 528 {
 529         clp->cl_cb_state = NFSD4_CB_DOWN;
 530         warn_no_callback_path(clp, reason);
 531 }
 532
 533 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
 534 {
 535         struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
 536
 537         if (task->tk_status)
 538                 nfsd4_mark_cb_down(clp, task->tk_status);
 539         else
 540                 clp->cl_cb_state = NFSD4_CB_UP;
 541 }
 542
 543 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
 544         /* XXX: release method to ensure we set the cb channel down if
 545          * necessary on early failure? */
 546         .rpc_call_done = nfsd4_cb_probe_done,
 547 };
 548
 549 static struct rpc_cred *callback_cred;
 550
 551 int set_callback_cred(void)
 552 {
 553         if (callback_cred)
 554                 return 0;
 555         callback_cred = rpc_lookup_machine_cred();
 556         if (!callback_cred)
 557                 return -ENOMEM;
 558         return 0;
 559 }
 560
 561 static struct workqueue_struct *callback_wq;
 562
 563 static void run_nfsd4_cb(struct nfsd4_callback *cb)
 564 {
 565         queue_work(callback_wq, &cb->cb_work);
 566 }
 567
 568 static void do_probe_callback(struct nfs4_client *clp)
 569 {
 570         struct nfsd4_callback *cb = &clp->cl_cb_null;
 571
 572         cb->cb_op = NULL;
 573         cb->cb_clp = clp;
 574
 575         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
 576         cb->cb_msg.rpc_argp = NULL;
 577         cb->cb_msg.rpc_resp = NULL;
 578         cb->cb_msg.rpc_cred = callback_cred;
 579
 580         cb->cb_ops = &nfsd4_cb_probe_ops;
 581
 582         run_nfsd4_cb(cb);
 583 }
 584
 585 /*
 586  * Poke the callback thread to process any updates to the callback
 587  * parameters, and send a null probe.
 588  */
 589 void nfsd4_probe_callback(struct nfs4_client *clp)
 590 {
 591         /* XXX: atomicity?  Also, should we be using cl_cb_flags? */
 592         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 593         set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
 594         do_probe_callback(clp);
 595 }
 596
 597 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
 598 {
 599         nfsd4_probe_callback(clp);
 600         flush_workqueue(callback_wq);
 601 }
 602
 603 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
 604 {
 605         clp->cl_cb_state = NFSD4_CB_UNKNOWN;
 606         spin_lock(&clp->cl_lock);
 607         memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
 608         spin_unlock(&clp->cl_lock);
 609 }
 610
 611 /*
 612  * There's currently a single callback channel slot.
 613  * If the slot is available, then mark it busy.  Otherwise, set the
 614  * thread for sleeping on the callback RPC wait queue.
 615  */
 616 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
 617 {
 618         if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
 619                 rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
 620                 dprintk("%s slot is busy\n", __func__);
 621                 return false;
 622         }
 623         return true;
 624 }
 625
 626 /*
 627  * TODO: cb_sequence should support referring call lists, cachethis, multiple
 628  * slots, and mark callback channel down on communication errors.
 629  */
 630 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 631 {
 632         struct nfsd4_callback *cb = calldata;
 633         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 634         struct nfs4_client *clp = dp->dl_client;
 635         u32 minorversion = clp->cl_minorversion;
 636
 637         cb->cb_minorversion = minorversion;
 638         if (minorversion) {
 639                 if (!nfsd41_cb_get_slot(clp, task))
 640                         return;
 641         }
 642         rpc_call_start(task);
 643 }
 644
 645 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 646 {
 647         struct nfsd4_callback *cb = calldata;
 648         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 649         struct nfs4_client *clp = dp->dl_client;
 650
 651         dprintk("%s: minorversion=%d\n", __func__,
 652                 clp->cl_minorversion);
 653
 654         if (clp->cl_minorversion) {
 655                 /* No need for lock, access serialized in nfsd4_cb_prepare */
 656                 ++clp->cl_cb_session->se_cb_seq_nr;
 657                 clear_bit(0, &clp->cl_cb_slot_busy);
 658                 rpc_wake_up_next(&clp->cl_cb_waitq);
 659                 dprintk("%s: freed slot, new seqid=%d\n", __func__,
 660                         clp->cl_cb_session->se_cb_seq_nr);
 661
 662                 /* We're done looking into the sequence information */
 663                 task->tk_msg.rpc_resp = NULL;
 664         }
 665 }
 666
 667
 668 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 669 {
 670         struct nfsd4_callback *cb = calldata;
 671         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 672         struct nfs4_client *clp = dp->dl_client;
 673         struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
 674
 675         nfsd4_cb_done(task, calldata);
 676
 677         if (current_rpc_client == NULL) {
 678                 /* We're shutting down; give up. */
 679                 /* XXX: err, or is it ok just to fall through
 680                  * and rpc_restart_call? */
 681                 return;
 682         }
 683
 684         switch (task->tk_status) {
 685         case 0:
 686                 return;
 687         case -EBADHANDLE:
 688         case -NFS4ERR_BAD_STATEID:
 689                 /* Race: client probably got cb_recall
 690                  * before open reply granting delegation */
 691                 break;
 692         default:
 693                 /* Network partition? */
 694                 nfsd4_mark_cb_down(clp, task->tk_status);
 695                 if (current_rpc_client != task->tk_client) {
 696                         /* queue a callback on the new connection: */
 697                         atomic_inc(&dp->dl_count);
 698                         nfsd4_cb_recall(dp);
 699                         return;
 700                 }
 701         }
 702         if (dp->dl_retries--) {
 703                 rpc_delay(task, 2*HZ);
 704                 task->tk_status = 0;
 705                 rpc_restart_call_prepare(task);
 706                 return;
 707         } else
 708                 nfsd4_mark_cb_down(clp, task->tk_status);
 709 }
 710
 711 static void nfsd4_cb_recall_release(void *calldata)
 712 {
 713         struct nfsd4_callback *cb = calldata;
 714         struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
 715
 716         nfs4_put_delegation(dp);
 717 }
 718
 719 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
 720         .rpc_call_prepare = nfsd4_cb_prepare,
 721         .rpc_call_done = nfsd4_cb_recall_done,
 722         .rpc_release = nfsd4_cb_recall_release,
 723 };
 724
 725 int nfsd4_create_callback_queue(void)
 726 {
 727         callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
 728         if (!callback_wq)
 729                 return -ENOMEM;
 730         return 0;
 731 }
 732
 733 void nfsd4_destroy_callback_queue(void)
 734 {
 735         destroy_workqueue(callback_wq);
 736 }
 737
 738 /* must be called under the state lock */
 739 void nfsd4_shutdown_callback(struct nfs4_client *clp)
 740 {
 741         set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
 742         /*
 743          * Note this won't actually result in a null callback;
 744          * instead, nfsd4_do_callback_rpc() will detect the killed
 745          * client, destroy the rpc client, and stop:
 746          */
 747         do_probe_callback(clp);
 748         flush_workqueue(callback_wq);
 749 }
 750
 751 static void nfsd4_release_cb(struct nfsd4_callback *cb)
 752 {
 753         if (cb->cb_ops->rpc_release)
 754                 cb->cb_ops->rpc_release(cb);
 755 }
 756
 757 /* requires cl_lock: */
 758 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
 759 {
 760         struct nfsd4_session *s;
 761         struct nfsd4_conn *c;
 762
 763         list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
 764                 list_for_each_entry(c, &s->se_conns, cn_persession) {
 765                         if (c->cn_flags & NFS4_CDFC4_BACK)
 766                                 return c;
 767                 }
 768         }
 769         return NULL;
 770 }
 771
 772 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
 773 {
 774         struct nfs4_cb_conn conn;
 775         struct nfs4_client *clp = cb->cb_clp;
 776         struct nfsd4_session *ses = NULL;
 777         struct nfsd4_conn *c;
 778         int err;
 779
 780         /*
 781          * This is either an update, or the client dying; in either case,
 782          * kill the old client:
 783          */
 784         if (clp->cl_cb_client) {
 785                 rpc_shutdown_client(clp->cl_cb_client);
 786                 clp->cl_cb_client = NULL;
 787         }
 788         if (clp->cl_cb_conn.cb_xprt) {
 789                 svc_xprt_put(clp->cl_cb_conn.cb_xprt);
 790                 clp->cl_cb_conn.cb_xprt = NULL;
 791         }
 792         if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
 793                 return;
 794         spin_lock(&clp->cl_lock);
 795         /*
 796          * Only serialized callback code is allowed to clear these
 797          * flags; main nfsd code can only set them:
 798          */
 799         BUG_ON(!clp->cl_cb_flags);
 800         clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
 801         memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
 802         c = __nfsd4_find_backchannel(clp);
 803         if (c) {
 804                 svc_xprt_get(c->cn_xprt);
 805                 conn.cb_xprt = c->cn_xprt;
 806                 ses = c->cn_session;
 807         }
 808         spin_unlock(&clp->cl_lock);
 809
 810         err = setup_callback_client(clp, &conn, ses);
 811         if (err)
 812                 warn_no_callback_path(clp, err);
 813 }
 814
 815 void nfsd4_do_callback_rpc(struct work_struct *w)
 816 {
 817         struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
 818         struct nfs4_client *clp = cb->cb_clp;
 819         struct rpc_clnt *clnt;
 820
 821         if (clp->cl_cb_flags)
 822                 nfsd4_process_cb_update(cb);
 823
 824         clnt = clp->cl_cb_client;
 825         if (!clnt) {
 826                 /* Callback channel broken, or client killed; give up: */
 827                 nfsd4_release_cb(cb);
 828                 return;
 829         }
 830         rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
 831                         cb->cb_ops, cb);
 832 }
 833
 834 void nfsd4_cb_recall(struct nfs4_delegation *dp)
 835 {
 836         struct nfsd4_callback *cb = &dp->dl_recall;
 837
 838         dp->dl_retries = 1;
 839         cb->cb_op = dp;
 840         cb->cb_clp = dp->dl_client;
 841         cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
 842         cb->cb_msg.rpc_argp = cb;
 843         cb->cb_msg.rpc_resp = cb;
 844         cb->cb_msg.rpc_cred = callback_cred;
 845
 846         cb->cb_ops = &nfsd4_cb_recall_ops;
 847         dp->dl_retries = 1;
 848
 849         run_nfsd4_cb(&dp->dl_recall);
 850 }