net/9p/client.c

   1 /*
   2  * net/9p/clnt.c
   3  *
   4  * 9P Client
   5  *
   6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2
  11  *  as published by the Free Software Foundation.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to:
  20  *  Free Software Foundation
  21  *  51 Franklin Street, Fifth Floor
  22  *  Boston, MA  02111-1301  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/fs.h>
  29 #include <linux/poll.h>
  30 #include <linux/idr.h>
  31 #include <linux/mutex.h>
  32 #include <linux/sched.h>
  33 #include <linux/uaccess.h>
  34 #include <net/9p/9p.h>
  35 #include <linux/parser.h>
  36 #include <net/9p/transport.h>
  37 #include <net/9p/client.h>
  38
  39 static struct p9_fid *p9_fid_create(struct p9_client *clnt);
  40 static void p9_fid_destroy(struct p9_fid *fid);
  41 static struct p9_stat *p9_clone_stat(struct p9_stat *st, int dotu);
  42
  43 /*
  44   * Client Option Parsing (code inspired by NFS code)
  45   *  - a little lazy - parse all client options
  46   */
  47
  48 enum {
  49         Opt_msize,
  50         Opt_trans,
  51         Opt_legacy,
  52         Opt_err,
  53 };
  54
  55 static match_table_t tokens = {
  56         {Opt_msize, "msize=%u"},
  57         {Opt_legacy, "noextend"},
  58         {Opt_trans, "trans=%s"},
  59         {Opt_err, NULL},
  60 };
  61
  62 /**
  63  * v9fs_parse_options - parse mount options into session structure
  64  * @options: options string passed from mount
  65  * @v9ses: existing v9fs session information
  66  *
  67  * Return 0 upon success, -ERRNO upon failure
  68  */
  69
  70 static int parse_opts(char *opts, struct p9_client *clnt)
  71 {
  72         char *options;
  73         char *p;
  74         substring_t args[MAX_OPT_ARGS];
  75         int option;
  76         int ret = 0;
  77
  78         clnt->dotu = 1;
  79         clnt->msize = 8192;
  80
  81         if (!opts)
  82                 return 0;
  83
  84         options = kstrdup(opts, GFP_KERNEL);
  85         if (!options) {
  86                 P9_DPRINTK(P9_DEBUG_ERROR,
  87                                 "failed to allocate copy of option string\n");
  88                 return -ENOMEM;
  89         }
  90
  91         while ((p = strsep(&options, ",")) != NULL) {
  92                 int token;
  93                 if (!*p)
  94                         continue;
  95                 token = match_token(p, tokens, args);
  96                 if (token < Opt_trans) {
  97                         int r = match_int(&args[0], &option);
  98                         if (r < 0) {
  99                                 P9_DPRINTK(P9_DEBUG_ERROR,
 100                                         "integer field, but no integer?\n");
 101                                 ret = r;
 102                                 continue;
 103                         }
 104                 }
 105                 switch (token) {
 106                 case Opt_msize:
 107                         clnt->msize = option;
 108                         break;
 109                 case Opt_trans:
 110                         clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
 111                         break;
 112                 case Opt_legacy:
 113                         clnt->dotu = 0;
 114                         break;
 115                 default:
 116                         continue;
 117                 }
 118         }
 119
 120         if (!clnt->trans_mod)
 121                 clnt->trans_mod = v9fs_get_default_trans();
 122
 123         kfree(options);
 124         return ret;
 125 }
 126
 127
 128 /**
 129  * p9_client_rpc - sends 9P request and waits until a response is available.
 130  *      The function can be interrupted.
 131  * @c: client data
 132  * @tc: request to be sent
 133  * @rc: pointer where a pointer to the response is stored
 134  */
 135 int
 136 p9_client_rpc(struct p9_client *c, struct p9_fcall *tc,
 137         struct p9_fcall **rc)
 138 {
 139         return c->trans->rpc(c->trans, tc, rc);
 140 }
 141
 142 struct p9_client *p9_client_create(const char *dev_name, char *options)
 143 {
 144         int err, n;
 145         struct p9_client *clnt;
 146         struct p9_fcall *tc, *rc;
 147         struct p9_str *version;
 148
 149         err = 0;
 150         tc = NULL;
 151         rc = NULL;
 152         clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
 153         if (!clnt)
 154                 return ERR_PTR(-ENOMEM);
 155
 156         clnt->trans_mod = NULL;
 157         clnt->trans = NULL;
 158         spin_lock_init(&clnt->lock);
 159         INIT_LIST_HEAD(&clnt->fidlist);
 160         clnt->fidpool = p9_idpool_create();
 161         if (IS_ERR(clnt->fidpool)) {
 162                 err = PTR_ERR(clnt->fidpool);
 163                 clnt->fidpool = NULL;
 164                 goto error;
 165         }
 166
 167         err = parse_opts(options, clnt);
 168         if (err < 0)
 169                 goto error;
 170
 171         if (clnt->trans_mod == NULL) {
 172                 err = -EPROTONOSUPPORT;
 173                 P9_DPRINTK(P9_DEBUG_ERROR,
 174                                 "No transport defined or default transport\n");
 175                 goto error;
 176         }
 177
 178         P9_DPRINTK(P9_DEBUG_9P, "clnt %p trans %p msize %d dotu %d\n",
 179                 clnt, clnt->trans_mod, clnt->msize, clnt->dotu);
 180
 181
 182         clnt->trans = clnt->trans_mod->create(dev_name, options, clnt->msize,
 183                                                                 clnt->dotu);
 184         if (IS_ERR(clnt->trans)) {
 185                 err = PTR_ERR(clnt->trans);
 186                 clnt->trans = NULL;
 187                 goto error;
 188         }
 189
 190         if ((clnt->msize+P9_IOHDRSZ) > clnt->trans_mod->maxsize)
 191                 clnt->msize = clnt->trans_mod->maxsize-P9_IOHDRSZ;
 192
 193         tc = p9_create_tversion(clnt->msize, clnt->dotu?"9P2000.u":"9P2000");
 194         if (IS_ERR(tc)) {
 195                 err = PTR_ERR(tc);
 196                 tc = NULL;
 197                 goto error;
 198         }
 199
 200         err = p9_client_rpc(clnt, tc, &rc);
 201         if (err)
 202                 goto error;
 203
 204         version = &rc->params.rversion.version;
 205         if (version->len == 8 && !memcmp(version->str, "9P2000.u", 8))
 206                 clnt->dotu = 1;
 207         else if (version->len == 6 && !memcmp(version->str, "9P2000", 6))
 208                 clnt->dotu = 0;
 209         else {
 210                 err = -EREMOTEIO;
 211                 goto error;
 212         }
 213
 214         n = rc->params.rversion.msize;
 215         if (n < clnt->msize)
 216                 clnt->msize = n;
 217
 218         kfree(tc);
 219         kfree(rc);
 220         return clnt;
 221
 222 error:
 223         kfree(tc);
 224         kfree(rc);
 225         p9_client_destroy(clnt);
 226         return ERR_PTR(err);
 227 }
 228 EXPORT_SYMBOL(p9_client_create);
 229
 230 void p9_client_destroy(struct p9_client *clnt)
 231 {
 232         struct p9_fid *fid, *fidptr;
 233
 234         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
 235
 236         if (clnt->trans) {
 237                 clnt->trans->close(clnt->trans);
 238                 kfree(clnt->trans);
 239                 clnt->trans = NULL;
 240         }
 241
 242         v9fs_put_trans(clnt->trans_mod);
 243
 244         list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
 245                 p9_fid_destroy(fid);
 246
 247         if (clnt->fidpool)
 248                 p9_idpool_destroy(clnt->fidpool);
 249
 250         kfree(clnt);
 251 }
 252 EXPORT_SYMBOL(p9_client_destroy);
 253
 254 void p9_client_disconnect(struct p9_client *clnt)
 255 {
 256         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
 257         clnt->trans->status = Disconnected;
 258 }
 259 EXPORT_SYMBOL(p9_client_disconnect);
 260
 261 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 262         char *uname, u32 n_uname, char *aname)
 263 {
 264         int err;
 265         struct p9_fcall *tc, *rc;
 266         struct p9_fid *fid;
 267
 268         P9_DPRINTK(P9_DEBUG_9P, "clnt %p afid %d uname %s aname %s\n",
 269                 clnt, afid?afid->fid:-1, uname, aname);
 270         err = 0;
 271         tc = NULL;
 272         rc = NULL;
 273
 274         fid = p9_fid_create(clnt);
 275         if (IS_ERR(fid)) {
 276                 err = PTR_ERR(fid);
 277                 fid = NULL;
 278                 goto error;
 279         }
 280
 281         tc = p9_create_tattach(fid->fid, afid?afid->fid:P9_NOFID, uname, aname,
 282                 n_uname, clnt->dotu);
 283         if (IS_ERR(tc)) {
 284                 err = PTR_ERR(tc);
 285                 tc = NULL;
 286                 goto error;
 287         }
 288
 289         err = p9_client_rpc(clnt, tc, &rc);
 290         if (err)
 291                 goto error;
 292
 293         memmove(&fid->qid, &rc->params.rattach.qid, sizeof(struct p9_qid));
 294         kfree(tc);
 295         kfree(rc);
 296         return fid;
 297
 298 error:
 299         kfree(tc);
 300         kfree(rc);
 301         if (fid)
 302                 p9_fid_destroy(fid);
 303         return ERR_PTR(err);
 304 }
 305 EXPORT_SYMBOL(p9_client_attach);
 306
 307 struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
 308         u32 n_uname, char *aname)
 309 {
 310         int err;
 311         struct p9_fcall *tc, *rc;
 312         struct p9_fid *fid;
 313
 314         P9_DPRINTK(P9_DEBUG_9P, "clnt %p uname %s aname %s\n", clnt, uname,
 315                                                                         aname);
 316         err = 0;
 317         tc = NULL;
 318         rc = NULL;
 319
 320         fid = p9_fid_create(clnt);
 321         if (IS_ERR(fid)) {
 322                 err = PTR_ERR(fid);
 323                 fid = NULL;
 324                 goto error;
 325         }
 326
 327         tc = p9_create_tauth(fid->fid, uname, aname, n_uname, clnt->dotu);
 328         if (IS_ERR(tc)) {
 329                 err = PTR_ERR(tc);
 330                 tc = NULL;
 331                 goto error;
 332         }
 333
 334         err = p9_client_rpc(clnt, tc, &rc);
 335         if (err)
 336                 goto error;
 337
 338         memmove(&fid->qid, &rc->params.rauth.qid, sizeof(struct p9_qid));
 339         kfree(tc);
 340         kfree(rc);
 341         return fid;
 342
 343 error:
 344         kfree(tc);
 345         kfree(rc);
 346         if (fid)
 347                 p9_fid_destroy(fid);
 348         return ERR_PTR(err);
 349 }
 350 EXPORT_SYMBOL(p9_client_auth);
 351
 352 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
 353         int clone)
 354 {
 355         int err;
 356         struct p9_fcall *tc, *rc;
 357         struct p9_client *clnt;
 358         struct p9_fid *fid;
 359
 360         P9_DPRINTK(P9_DEBUG_9P, "fid %d nwname %d wname[0] %s\n",
 361                 oldfid->fid, nwname, wnames?wnames[0]:NULL);
 362         err = 0;
 363         tc = NULL;
 364         rc = NULL;
 365         clnt = oldfid->clnt;
 366         if (clone) {
 367                 fid = p9_fid_create(clnt);
 368                 if (IS_ERR(fid)) {
 369                         err = PTR_ERR(fid);
 370                         fid = NULL;
 371                         goto error;
 372                 }
 373
 374                 fid->uid = oldfid->uid;
 375         } else
 376                 fid = oldfid;
 377
 378         tc = p9_create_twalk(oldfid->fid, fid->fid, nwname, wnames);
 379         if (IS_ERR(tc)) {
 380                 err = PTR_ERR(tc);
 381                 tc = NULL;
 382                 goto error;
 383         }
 384
 385         err = p9_client_rpc(clnt, tc, &rc);
 386         if (err) {
 387                 if (rc && rc->id == P9_RWALK)
 388                         goto clunk_fid;
 389                 else
 390                         goto error;
 391         }
 392
 393         if (rc->params.rwalk.nwqid != nwname) {
 394                 err = -ENOENT;
 395                 goto clunk_fid;
 396         }
 397
 398         if (nwname)
 399                 memmove(&fid->qid,
 400                         &rc->params.rwalk.wqids[rc->params.rwalk.nwqid - 1],
 401                         sizeof(struct p9_qid));
 402         else
 403                 fid->qid = oldfid->qid;
 404
 405         kfree(tc);
 406         kfree(rc);
 407         return fid;
 408
 409 clunk_fid:
 410         kfree(tc);
 411         kfree(rc);
 412         rc = NULL;
 413         tc = p9_create_tclunk(fid->fid);
 414         if (IS_ERR(tc)) {
 415                 err = PTR_ERR(tc);
 416                 tc = NULL;
 417                 goto error;
 418         }
 419
 420         p9_client_rpc(clnt, tc, &rc);
 421
 422 error:
 423         kfree(tc);
 424         kfree(rc);
 425         if (fid && (fid != oldfid))
 426                 p9_fid_destroy(fid);
 427
 428         return ERR_PTR(err);
 429 }
 430 EXPORT_SYMBOL(p9_client_walk);
 431
 432 int p9_client_open(struct p9_fid *fid, int mode)
 433 {
 434         int err;
 435         struct p9_fcall *tc, *rc;
 436         struct p9_client *clnt;
 437
 438         P9_DPRINTK(P9_DEBUG_9P, "fid %d mode %d\n", fid->fid, mode);
 439         err = 0;
 440         tc = NULL;
 441         rc = NULL;
 442         clnt = fid->clnt;
 443
 444         if (fid->mode != -1)
 445                 return -EINVAL;
 446
 447         tc = p9_create_topen(fid->fid, mode);
 448         if (IS_ERR(tc)) {
 449                 err = PTR_ERR(tc);
 450                 tc = NULL;
 451                 goto done;
 452         }
 453
 454         err = p9_client_rpc(clnt, tc, &rc);
 455         if (err)
 456                 goto done;
 457
 458         fid->mode = mode;
 459         fid->iounit = rc->params.ropen.iounit;
 460
 461 done:
 462         kfree(tc);
 463         kfree(rc);
 464         return err;
 465 }
 466 EXPORT_SYMBOL(p9_client_open);
 467
 468 int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
 469                      char *extension)
 470 {
 471         int err;
 472         struct p9_fcall *tc, *rc;
 473         struct p9_client *clnt;
 474
 475         P9_DPRINTK(P9_DEBUG_9P, "fid %d name %s perm %d mode %d\n", fid->fid,
 476                 name, perm, mode);
 477         err = 0;
 478         tc = NULL;
 479         rc = NULL;
 480         clnt = fid->clnt;
 481
 482         if (fid->mode != -1)
 483                 return -EINVAL;
 484
 485         tc = p9_create_tcreate(fid->fid, name, perm, mode, extension,
 486                                                                clnt->dotu);
 487         if (IS_ERR(tc)) {
 488                 err = PTR_ERR(tc);
 489                 tc = NULL;
 490                 goto done;
 491         }
 492
 493         err = p9_client_rpc(clnt, tc, &rc);
 494         if (err)
 495                 goto done;
 496
 497         fid->mode = mode;
 498         fid->iounit = rc->params.ropen.iounit;
 499
 500 done:
 501         kfree(tc);
 502         kfree(rc);
 503         return err;
 504 }
 505 EXPORT_SYMBOL(p9_client_fcreate);
 506
 507 int p9_client_clunk(struct p9_fid *fid)
 508 {
 509         int err;
 510         struct p9_fcall *tc, *rc;
 511         struct p9_client *clnt;
 512
 513         P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
 514         err = 0;
 515         tc = NULL;
 516         rc = NULL;
 517         clnt = fid->clnt;
 518
 519         tc = p9_create_tclunk(fid->fid);
 520         if (IS_ERR(tc)) {
 521                 err = PTR_ERR(tc);
 522                 tc = NULL;
 523                 goto done;
 524         }
 525
 526         err = p9_client_rpc(clnt, tc, &rc);
 527         if (err)
 528                 goto done;
 529
 530         p9_fid_destroy(fid);
 531
 532 done:
 533         kfree(tc);
 534         kfree(rc);
 535         return err;
 536 }
 537 EXPORT_SYMBOL(p9_client_clunk);
 538
 539 int p9_client_remove(struct p9_fid *fid)
 540 {
 541         int err;
 542         struct p9_fcall *tc, *rc;
 543         struct p9_client *clnt;
 544
 545         P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
 546         err = 0;
 547         tc = NULL;
 548         rc = NULL;
 549         clnt = fid->clnt;
 550
 551         tc = p9_create_tremove(fid->fid);
 552         if (IS_ERR(tc)) {
 553                 err = PTR_ERR(tc);
 554                 tc = NULL;
 555                 goto done;
 556         }
 557
 558         err = p9_client_rpc(clnt, tc, &rc);
 559         if (err)
 560                 goto done;
 561
 562         p9_fid_destroy(fid);
 563
 564 done:
 565         kfree(tc);
 566         kfree(rc);
 567         return err;
 568 }
 569 EXPORT_SYMBOL(p9_client_remove);
 570
 571 int p9_client_read(struct p9_fid *fid, char *data, u64 offset, u32 count)
 572 {
 573         int err, n, rsize, total;
 574         struct p9_fcall *tc, *rc;
 575         struct p9_client *clnt;
 576
 577         P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu %d\n", fid->fid,
 578                                         (long long unsigned) offset, count);
 579         err = 0;
 580         tc = NULL;
 581         rc = NULL;
 582         clnt = fid->clnt;
 583         total = 0;
 584
 585         rsize = fid->iounit;
 586         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
 587                 rsize = clnt->msize - P9_IOHDRSZ;
 588
 589         do {
 590                 if (count < rsize)
 591                         rsize = count;
 592
 593                 tc = p9_create_tread(fid->fid, offset, rsize);
 594                 if (IS_ERR(tc)) {
 595                         err = PTR_ERR(tc);
 596                         tc = NULL;
 597                         goto error;
 598                 }
 599
 600                 err = p9_client_rpc(clnt, tc, &rc);
 601                 if (err)
 602                         goto error;
 603
 604                 n = rc->params.rread.count;
 605                 if (n > count)
 606                         n = count;
 607
 608                 memmove(data, rc->params.rread.data, n);
 609                 count -= n;
 610                 data += n;
 611                 offset += n;
 612                 total += n;
 613                 kfree(tc);
 614                 tc = NULL;
 615                 kfree(rc);
 616                 rc = NULL;
 617         } while (count > 0 && n == rsize);
 618
 619         return total;
 620
 621 error:
 622         kfree(tc);
 623         kfree(rc);
 624         return err;
 625 }
 626 EXPORT_SYMBOL(p9_client_read);
 627
 628 int p9_client_write(struct p9_fid *fid, char *data, u64 offset, u32 count)
 629 {
 630         int err, n, rsize, total;
 631         struct p9_fcall *tc, *rc;
 632         struct p9_client *clnt;
 633
 634         P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
 635                                         (long long unsigned) offset, count);
 636         err = 0;
 637         tc = NULL;
 638         rc = NULL;
 639         clnt = fid->clnt;
 640         total = 0;
 641
 642         rsize = fid->iounit;
 643         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
 644                 rsize = clnt->msize - P9_IOHDRSZ;
 645
 646         do {
 647                 if (count < rsize)
 648                         rsize = count;
 649
 650                 tc = p9_create_twrite(fid->fid, offset, rsize, data);
 651                 if (IS_ERR(tc)) {
 652                         err = PTR_ERR(tc);
 653                         tc = NULL;
 654                         goto error;
 655                 }
 656
 657                 err = p9_client_rpc(clnt, tc, &rc);
 658                 if (err)
 659                         goto error;
 660
 661                 n = rc->params.rread.count;
 662                 count -= n;
 663                 data += n;
 664                 offset += n;
 665                 total += n;
 666                 kfree(tc);
 667                 tc = NULL;
 668                 kfree(rc);
 669                 rc = NULL;
 670         } while (count > 0);
 671
 672         return total;
 673
 674 error:
 675         kfree(tc);
 676         kfree(rc);
 677         return err;
 678 }
 679 EXPORT_SYMBOL(p9_client_write);
 680
 681 int
 682 p9_client_uread(struct p9_fid *fid, char __user *data, u64 offset, u32 count)
 683 {
 684         int err, n, rsize, total;
 685         struct p9_fcall *tc, *rc;
 686         struct p9_client *clnt;
 687
 688         P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
 689                                         (long long unsigned) offset, count);
 690         err = 0;
 691         tc = NULL;
 692         rc = NULL;
 693         clnt = fid->clnt;
 694         total = 0;
 695
 696         rsize = fid->iounit;
 697         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
 698                 rsize = clnt->msize - P9_IOHDRSZ;
 699
 700         do {
 701                 if (count < rsize)
 702                         rsize = count;
 703
 704                 tc = p9_create_tread(fid->fid, offset, rsize);
 705                 if (IS_ERR(tc)) {
 706                         err = PTR_ERR(tc);
 707                         tc = NULL;
 708                         goto error;
 709                 }
 710
 711                 err = p9_client_rpc(clnt, tc, &rc);
 712                 if (err)
 713                         goto error;
 714
 715                 n = rc->params.rread.count;
 716                 if (n > count)
 717                         n = count;
 718
 719                 err = copy_to_user(data, rc->params.rread.data, n);
 720                 if (err) {
 721                         err = -EFAULT;
 722                         goto error;
 723                 }
 724
 725                 count -= n;
 726                 data += n;
 727                 offset += n;
 728                 total += n;
 729                 kfree(tc);
 730                 tc = NULL;
 731                 kfree(rc);
 732                 rc = NULL;
 733         } while (count > 0 && n == rsize);
 734
 735         return total;
 736
 737 error:
 738         kfree(tc);
 739         kfree(rc);
 740         return err;
 741 }
 742 EXPORT_SYMBOL(p9_client_uread);
 743
 744 int
 745 p9_client_uwrite(struct p9_fid *fid, const char __user *data, u64 offset,
 746                                                                    u32 count)
 747 {
 748         int err, n, rsize, total;
 749         struct p9_fcall *tc, *rc;
 750         struct p9_client *clnt;
 751
 752         P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
 753                                         (long long unsigned) offset, count);
 754         err = 0;
 755         tc = NULL;
 756         rc = NULL;
 757         clnt = fid->clnt;
 758         total = 0;
 759
 760         rsize = fid->iounit;
 761         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
 762                 rsize = clnt->msize - P9_IOHDRSZ;
 763
 764         do {
 765                 if (count < rsize)
 766                         rsize = count;
 767
 768                 tc = p9_create_twrite_u(fid->fid, offset, rsize, data);
 769                 if (IS_ERR(tc)) {
 770                         err = PTR_ERR(tc);
 771                         tc = NULL;
 772                         goto error;
 773                 }
 774
 775                 err = p9_client_rpc(clnt, tc, &rc);
 776                 if (err)
 777                         goto error;
 778
 779                 n = rc->params.rread.count;
 780                 count -= n;
 781                 data += n;
 782                 offset += n;
 783                 total += n;
 784                 kfree(tc);
 785                 tc = NULL;
 786                 kfree(rc);
 787                 rc = NULL;
 788         } while (count > 0);
 789
 790         return total;
 791
 792 error:
 793         kfree(tc);
 794         kfree(rc);
 795         return err;
 796 }
 797 EXPORT_SYMBOL(p9_client_uwrite);
 798
 799 int p9_client_readn(struct p9_fid *fid, char *data, u64 offset, u32 count)
 800 {
 801         int n, total;
 802
 803         P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu count %d\n", fid->fid,
 804                                         (long long unsigned) offset, count);
 805         n = 0;
 806         total = 0;
 807         while (count) {
 808                 n = p9_client_read(fid, data, offset, count);
 809                 if (n <= 0)
 810                         break;
 811
 812                 data += n;
 813                 offset += n;
 814                 count -= n;
 815                 total += n;
 816         }
 817
 818         if (n < 0)
 819                 total = n;
 820
 821         return total;
 822 }
 823 EXPORT_SYMBOL(p9_client_readn);
 824
 825 struct p9_stat *p9_client_stat(struct p9_fid *fid)
 826 {
 827         int err;
 828         struct p9_fcall *tc, *rc;
 829         struct p9_client *clnt;
 830         struct p9_stat *ret;
 831
 832         P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
 833         err = 0;
 834         tc = NULL;
 835         rc = NULL;
 836         ret = NULL;
 837         clnt = fid->clnt;
 838
 839         tc = p9_create_tstat(fid->fid);
 840         if (IS_ERR(tc)) {
 841                 err = PTR_ERR(tc);
 842                 tc = NULL;
 843                 goto error;
 844         }
 845
 846         err = p9_client_rpc(clnt, tc, &rc);
 847         if (err)
 848                 goto error;
 849
 850         ret = p9_clone_stat(&rc->params.rstat.stat, clnt->dotu);
 851         if (IS_ERR(ret)) {
 852                 err = PTR_ERR(ret);
 853                 ret = NULL;
 854                 goto error;
 855         }
 856
 857         kfree(tc);
 858         kfree(rc);
 859         return ret;
 860
 861 error:
 862         kfree(tc);
 863         kfree(rc);
 864         kfree(ret);
 865         return ERR_PTR(err);
 866 }
 867 EXPORT_SYMBOL(p9_client_stat);
 868
 869 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
 870 {
 871         int err;
 872         struct p9_fcall *tc, *rc;
 873         struct p9_client *clnt;
 874
 875         P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
 876         err = 0;
 877         tc = NULL;
 878         rc = NULL;
 879         clnt = fid->clnt;
 880
 881         tc = p9_create_twstat(fid->fid, wst, clnt->dotu);
 882         if (IS_ERR(tc)) {
 883                 err = PTR_ERR(tc);
 884                 tc = NULL;
 885                 goto done;
 886         }
 887
 888         err = p9_client_rpc(clnt, tc, &rc);
 889
 890 done:
 891         kfree(tc);
 892         kfree(rc);
 893         return err;
 894 }
 895 EXPORT_SYMBOL(p9_client_wstat);
 896
 897 struct p9_stat *p9_client_dirread(struct p9_fid *fid, u64 offset)
 898 {
 899         int err, n, m;
 900         struct p9_fcall *tc, *rc;
 901         struct p9_client *clnt;
 902         struct p9_stat st, *ret;
 903
 904         P9_DPRINTK(P9_DEBUG_9P, "fid %d offset %llu\n", fid->fid,
 905                                                 (long long unsigned) offset);
 906         err = 0;
 907         tc = NULL;
 908         rc = NULL;
 909         ret = NULL;
 910         clnt = fid->clnt;
 911
 912         /* if the offset is below or above the current response, free it */
 913         if (offset < fid->rdir_fpos || (fid->rdir_fcall &&
 914                 offset >= fid->rdir_fpos+fid->rdir_fcall->params.rread.count)) {
 915                 fid->rdir_pos = 0;
 916                 if (fid->rdir_fcall)
 917                         fid->rdir_fpos += fid->rdir_fcall->params.rread.count;
 918
 919                 kfree(fid->rdir_fcall);
 920                 fid->rdir_fcall = NULL;
 921                 if (offset < fid->rdir_fpos)
 922                         fid->rdir_fpos = 0;
 923         }
 924
 925         if (!fid->rdir_fcall) {
 926                 n = fid->iounit;
 927                 if (!n || n > clnt->msize-P9_IOHDRSZ)
 928                         n = clnt->msize - P9_IOHDRSZ;
 929
 930                 while (1) {
 931                         if (fid->rdir_fcall) {
 932                                 fid->rdir_fpos +=
 933                                         fid->rdir_fcall->params.rread.count;
 934                                 kfree(fid->rdir_fcall);
 935                                 fid->rdir_fcall = NULL;
 936                         }
 937
 938                         tc = p9_create_tread(fid->fid, fid->rdir_fpos, n);
 939                         if (IS_ERR(tc)) {
 940                                 err = PTR_ERR(tc);
 941                                 tc = NULL;
 942                                 goto error;
 943                         }
 944
 945                         err = p9_client_rpc(clnt, tc, &rc);
 946                         if (err)
 947                                 goto error;
 948
 949                         n = rc->params.rread.count;
 950                         if (n == 0)
 951                                 goto done;
 952
 953                         fid->rdir_fcall = rc;
 954                         rc = NULL;
 955                         if (offset >= fid->rdir_fpos &&
 956                                                 offset < fid->rdir_fpos+n)
 957                                 break;
 958                 }
 959
 960                 fid->rdir_pos = 0;
 961         }
 962
 963         m = offset - fid->rdir_fpos;
 964         if (m < 0)
 965                 goto done;
 966
 967         n = p9_deserialize_stat(fid->rdir_fcall->params.rread.data + m,
 968                 fid->rdir_fcall->params.rread.count - m, &st, clnt->dotu);
 969
 970         if (!n) {
 971                 err = -EIO;
 972                 goto error;
 973         }
 974
 975         fid->rdir_pos += n;
 976         st.size = n;
 977         ret = p9_clone_stat(&st, clnt->dotu);
 978         if (IS_ERR(ret)) {
 979                 err = PTR_ERR(ret);
 980                 ret = NULL;
 981                 goto error;
 982         }
 983
 984 done:
 985         kfree(tc);
 986         kfree(rc);
 987         return ret;
 988
 989 error:
 990         kfree(tc);
 991         kfree(rc);
 992         kfree(ret);
 993         return ERR_PTR(err);
 994 }
 995 EXPORT_SYMBOL(p9_client_dirread);
 996
 997 static struct p9_stat *p9_clone_stat(struct p9_stat *st, int dotu)
 998 {
 999         int n;
1000         char *p;
1001         struct p9_stat *ret;
1002
1003         n = sizeof(struct p9_stat) + st->name.len + st->uid.len + st->gid.len +
1004                 st->muid.len;
1005
1006         if (dotu)
1007                 n += st->extension.len;
1008
1009         ret = kmalloc(n, GFP_KERNEL);
1010         if (!ret)
1011                 return ERR_PTR(-ENOMEM);
1012
1013         memmove(ret, st, sizeof(struct p9_stat));
1014         p = ((char *) ret) + sizeof(struct p9_stat);
1015         memmove(p, st->name.str, st->name.len);
1016         ret->name.str = p;
1017         p += st->name.len;
1018         memmove(p, st->uid.str, st->uid.len);
1019         ret->uid.str = p;
1020         p += st->uid.len;
1021         memmove(p, st->gid.str, st->gid.len);
1022         ret->gid.str = p;
1023         p += st->gid.len;
1024         memmove(p, st->muid.str, st->muid.len);
1025         ret->muid.str = p;
1026         p += st->muid.len;
1027
1028         if (dotu) {
1029                 memmove(p, st->extension.str, st->extension.len);
1030                 ret->extension.str = p;
1031                 p += st->extension.len;
1032         }
1033
1034         return ret;
1035 }
1036
1037 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
1038 {
1039         int err;
1040         struct p9_fid *fid;
1041
1042         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
1043         fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
1044         if (!fid)
1045                 return ERR_PTR(-ENOMEM);
1046
1047         fid->fid = p9_idpool_get(clnt->fidpool);
1048         if (fid->fid < 0) {
1049                 err = -ENOSPC;
1050                 goto error;
1051         }
1052
1053         memset(&fid->qid, 0, sizeof(struct p9_qid));
1054         fid->mode = -1;
1055         fid->rdir_fpos = 0;
1056         fid->rdir_pos = 0;
1057         fid->rdir_fcall = NULL;
1058         fid->uid = current->fsuid;
1059         fid->clnt = clnt;
1060         fid->aux = NULL;
1061
1062         spin_lock(&clnt->lock);
1063         list_add(&fid->flist, &clnt->fidlist);
1064         spin_unlock(&clnt->lock);
1065
1066         return fid;
1067
1068 error:
1069         kfree(fid);
1070         return ERR_PTR(err);
1071 }
1072
1073 static void p9_fid_destroy(struct p9_fid *fid)
1074 {
1075         struct p9_client *clnt;
1076
1077         P9_DPRINTK(P9_DEBUG_9P, "fid %d\n", fid->fid);
1078         clnt = fid->clnt;
1079         p9_idpool_put(fid->fid, clnt->fidpool);
1080         spin_lock(&clnt->lock);
1081         list_del(&fid->flist);
1082         spin_unlock(&clnt->lock);
1083         kfree(fid->rdir_fcall);
1084         kfree(fid);
1085 }