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/slab.h>
  33 #include <linux/sched.h>
  34 #include <linux/uaccess.h>
  35 #include <net/9p/9p.h>
  36 #include <linux/parser.h>
  37 #include <net/9p/client.h>
  38 #include <net/9p/transport.h>
  39 #include "protocol.h"
  40
  41 /*
  42   * Client Option Parsing (code inspired by NFS code)
  43   *  - a little lazy - parse all client options
  44   */
  45
  46 enum {
  47         Opt_msize,
  48         Opt_trans,
  49         Opt_legacy,
  50         Opt_version,
  51         Opt_err,
  52 };
  53
  54 static const match_table_t tokens = {
  55         {Opt_msize, "msize=%u"},
  56         {Opt_legacy, "noextend"},
  57         {Opt_trans, "trans=%s"},
  58         {Opt_version, "version=%s"},
  59         {Opt_err, NULL},
  60 };
  61
  62 inline int p9_is_proto_dotl(struct p9_client *clnt)
  63 {
  64         return clnt->proto_version == p9_proto_2000L;
  65 }
  66 EXPORT_SYMBOL(p9_is_proto_dotl);
  67
  68 inline int p9_is_proto_dotu(struct p9_client *clnt)
  69 {
  70         return clnt->proto_version == p9_proto_2000u;
  71 }
  72 EXPORT_SYMBOL(p9_is_proto_dotu);
  73
  74 /* Interpret mount option for protocol version */
  75 static int get_protocol_version(const substring_t *name)
  76 {
  77         int version = -EINVAL;
  78
  79         if (!strncmp("9p2000", name->from, name->to-name->from)) {
  80                 version = p9_proto_legacy;
  81                 P9_DPRINTK(P9_DEBUG_9P, "Protocol version: Legacy\n");
  82         } else if (!strncmp("9p2000.u", name->from, name->to-name->from)) {
  83                 version = p9_proto_2000u;
  84                 P9_DPRINTK(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
  85         } else if (!strncmp("9p2000.L", name->from, name->to-name->from)) {
  86                 version = p9_proto_2000L;
  87                 P9_DPRINTK(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
  88         } else {
  89                 P9_DPRINTK(P9_DEBUG_ERROR, "Unknown protocol version %s. ",
  90                                                         name->from);
  91         }
  92         return version;
  93 }
  94
  95 /**
  96  * parse_options - parse mount options into client structure
  97  * @opts: options string passed from mount
  98  * @clnt: existing v9fs client information
  99  *
 100  * Return 0 upon success, -ERRNO upon failure
 101  */
 102
 103 static int parse_opts(char *opts, struct p9_client *clnt)
 104 {
 105         char *options, *tmp_options;
 106         char *p;
 107         substring_t args[MAX_OPT_ARGS];
 108         int option;
 109         int ret = 0;
 110
 111         clnt->proto_version = p9_proto_2000u;
 112         clnt->msize = 8192;
 113
 114         if (!opts)
 115                 return 0;
 116
 117         tmp_options = kstrdup(opts, GFP_KERNEL);
 118         if (!tmp_options) {
 119                 P9_DPRINTK(P9_DEBUG_ERROR,
 120                                 "failed to allocate copy of option string\n");
 121                 return -ENOMEM;
 122         }
 123         options = tmp_options;
 124
 125         while ((p = strsep(&options, ",")) != NULL) {
 126                 int token;
 127                 if (!*p)
 128                         continue;
 129                 token = match_token(p, tokens, args);
 130                 if (token < Opt_trans) {
 131                         int r = match_int(&args[0], &option);
 132                         if (r < 0) {
 133                                 P9_DPRINTK(P9_DEBUG_ERROR,
 134                                         "integer field, but no integer?\n");
 135                                 ret = r;
 136                                 continue;
 137                         }
 138                 }
 139                 switch (token) {
 140                 case Opt_msize:
 141                         clnt->msize = option;
 142                         break;
 143                 case Opt_trans:
 144                         clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
 145                         if(clnt->trans_mod == NULL) {
 146                                 P9_DPRINTK(P9_DEBUG_ERROR,
 147                                    "Could not find request transport: %s\n",
 148                                    (char *) &args[0]);
 149                                 ret = -EINVAL;
 150                                 goto free_and_return;
 151                         }
 152                         break;
 153                 case Opt_legacy:
 154                         clnt->proto_version = p9_proto_legacy;
 155                         break;
 156                 case Opt_version:
 157                         ret = get_protocol_version(&args[0]);
 158                         if (ret == -EINVAL)
 159                                 goto free_and_return;
 160                         clnt->proto_version = ret;
 161                         break;
 162                 default:
 163                         continue;
 164                 }
 165         }
 166
 167 free_and_return:
 168         kfree(tmp_options);
 169         return ret;
 170 }
 171
 172 /**
 173  * p9_tag_alloc - lookup/allocate a request by tag
 174  * @c: client session to lookup tag within
 175  * @tag: numeric id for transaction
 176  *
 177  * this is a simple array lookup, but will grow the
 178  * request_slots as necessary to accommodate transaction
 179  * ids which did not previously have a slot.
 180  *
 181  * this code relies on the client spinlock to manage locks, its
 182  * possible we should switch to something else, but I'd rather
 183  * stick with something low-overhead for the common case.
 184  *
 185  */
 186
 187 static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
 188 {
 189         unsigned long flags;
 190         int row, col;
 191         struct p9_req_t *req;
 192
 193         /* This looks up the original request by tag so we know which
 194          * buffer to read the data into */
 195         tag++;
 196
 197         if (tag >= c->max_tag) {
 198                 spin_lock_irqsave(&c->lock, flags);
 199                 /* check again since original check was outside of lock */
 200                 while (tag >= c->max_tag) {
 201                         row = (tag / P9_ROW_MAXTAG);
 202                         c->reqs[row] = kcalloc(P9_ROW_MAXTAG,
 203                                         sizeof(struct p9_req_t), GFP_ATOMIC);
 204
 205                         if (!c->reqs[row]) {
 206                                 printk(KERN_ERR "Couldn't grow tag array\n");
 207                                 spin_unlock_irqrestore(&c->lock, flags);
 208                                 return ERR_PTR(-ENOMEM);
 209                         }
 210                         for (col = 0; col < P9_ROW_MAXTAG; col++) {
 211                                 c->reqs[row][col].status = REQ_STATUS_IDLE;
 212                                 c->reqs[row][col].tc = NULL;
 213                         }
 214                         c->max_tag += P9_ROW_MAXTAG;
 215                 }
 216                 spin_unlock_irqrestore(&c->lock, flags);
 217         }
 218         row = tag / P9_ROW_MAXTAG;
 219         col = tag % P9_ROW_MAXTAG;
 220
 221         req = &c->reqs[row][col];
 222         if (!req->tc) {
 223                 req->wq = kmalloc(sizeof(wait_queue_head_t), GFP_NOFS);
 224                 if (!req->wq) {
 225                         printk(KERN_ERR "Couldn't grow tag array\n");
 226                         return ERR_PTR(-ENOMEM);
 227                 }
 228                 init_waitqueue_head(req->wq);
 229                 if ((c->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
 230                                 P9_TRANS_PREF_PAYLOAD_SEP) {
 231                         int alloc_msize = min(c->msize, 4096);
 232                         req->tc = kmalloc(sizeof(struct p9_fcall)+alloc_msize,
 233                                           GFP_NOFS);
 234                         req->tc->capacity = alloc_msize;
 235                         req->rc = kmalloc(sizeof(struct p9_fcall)+alloc_msize,
 236                                           GFP_NOFS);
 237                         req->rc->capacity = alloc_msize;
 238                 } else {
 239                         req->tc = kmalloc(sizeof(struct p9_fcall)+c->msize,
 240                                           GFP_NOFS);
 241                         req->tc->capacity = c->msize;
 242                         req->rc = kmalloc(sizeof(struct p9_fcall)+c->msize,
 243                                           GFP_NOFS);
 244                         req->rc->capacity = c->msize;
 245                 }
 246                 if ((!req->tc) || (!req->rc)) {
 247                         printk(KERN_ERR "Couldn't grow tag array\n");
 248                         kfree(req->tc);
 249                         kfree(req->rc);
 250                         kfree(req->wq);
 251                         req->tc = req->rc = NULL;
 252                         req->wq = NULL;
 253                         return ERR_PTR(-ENOMEM);
 254                 }
 255                 req->tc->sdata = (char *) req->tc + sizeof(struct p9_fcall);
 256                 req->rc->sdata = (char *) req->rc + sizeof(struct p9_fcall);
 257         }
 258
 259         p9pdu_reset(req->tc);
 260         p9pdu_reset(req->rc);
 261
 262         req->tc->tag = tag-1;
 263         req->status = REQ_STATUS_ALLOC;
 264
 265         return &c->reqs[row][col];
 266 }
 267
 268 /**
 269  * p9_tag_lookup - lookup a request by tag
 270  * @c: client session to lookup tag within
 271  * @tag: numeric id for transaction
 272  *
 273  */
 274
 275 struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
 276 {
 277         int row, col;
 278
 279         /* This looks up the original request by tag so we know which
 280          * buffer to read the data into */
 281         tag++;
 282
 283         BUG_ON(tag >= c->max_tag);
 284
 285         row = tag / P9_ROW_MAXTAG;
 286         col = tag % P9_ROW_MAXTAG;
 287
 288         return &c->reqs[row][col];
 289 }
 290 EXPORT_SYMBOL(p9_tag_lookup);
 291
 292 /**
 293  * p9_tag_init - setup tags structure and contents
 294  * @c:  v9fs client struct
 295  *
 296  * This initializes the tags structure for each client instance.
 297  *
 298  */
 299
 300 static int p9_tag_init(struct p9_client *c)
 301 {
 302         int err = 0;
 303
 304         c->tagpool = p9_idpool_create();
 305         if (IS_ERR(c->tagpool)) {
 306                 err = PTR_ERR(c->tagpool);
 307                 goto error;
 308         }
 309         err = p9_idpool_get(c->tagpool); /* reserve tag 0 */
 310         if (err < 0) {
 311                 p9_idpool_destroy(c->tagpool);
 312                 goto error;
 313         }
 314         c->max_tag = 0;
 315 error:
 316         return err;
 317 }
 318
 319 /**
 320  * p9_tag_cleanup - cleans up tags structure and reclaims resources
 321  * @c:  v9fs client struct
 322  *
 323  * This frees resources associated with the tags structure
 324  *
 325  */
 326 static void p9_tag_cleanup(struct p9_client *c)
 327 {
 328         int row, col;
 329
 330         /* check to insure all requests are idle */
 331         for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
 332                 for (col = 0; col < P9_ROW_MAXTAG; col++) {
 333                         if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
 334                                 P9_DPRINTK(P9_DEBUG_MUX,
 335                                   "Attempting to cleanup non-free tag %d,%d\n",
 336                                   row, col);
 337                                 /* TODO: delay execution of cleanup */
 338                                 return;
 339                         }
 340                 }
 341         }
 342
 343         if (c->tagpool) {
 344                 p9_idpool_put(0, c->tagpool); /* free reserved tag 0 */
 345                 p9_idpool_destroy(c->tagpool);
 346         }
 347
 348         /* free requests associated with tags */
 349         for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
 350                 for (col = 0; col < P9_ROW_MAXTAG; col++) {
 351                         kfree(c->reqs[row][col].wq);
 352                         kfree(c->reqs[row][col].tc);
 353                         kfree(c->reqs[row][col].rc);
 354                 }
 355                 kfree(c->reqs[row]);
 356         }
 357         c->max_tag = 0;
 358 }
 359
 360 /**
 361  * p9_free_req - free a request and clean-up as necessary
 362  * c: client state
 363  * r: request to release
 364  *
 365  */
 366
 367 static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
 368 {
 369         int tag = r->tc->tag;
 370         P9_DPRINTK(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
 371
 372         r->status = REQ_STATUS_IDLE;
 373         if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
 374                 p9_idpool_put(tag, c->tagpool);
 375 }
 376
 377 /**
 378  * p9_client_cb - call back from transport to client
 379  * c: client state
 380  * req: request received
 381  *
 382  */
 383 void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
 384 {
 385         P9_DPRINTK(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
 386         wake_up(req->wq);
 387         P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
 388 }
 389 EXPORT_SYMBOL(p9_client_cb);
 390
 391 /**
 392  * p9_parse_header - parse header arguments out of a packet
 393  * @pdu: packet to parse
 394  * @size: size of packet
 395  * @type: type of request
 396  * @tag: tag of packet
 397  * @rewind: set if we need to rewind offset afterwards
 398  */
 399
 400 int
 401 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
 402                                                                 int rewind)
 403 {
 404         int8_t r_type;
 405         int16_t r_tag;
 406         int32_t r_size;
 407         int offset = pdu->offset;
 408         int err;
 409
 410         pdu->offset = 0;
 411         if (pdu->size == 0)
 412                 pdu->size = 7;
 413
 414         err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
 415         if (err)
 416                 goto rewind_and_exit;
 417
 418         pdu->size = r_size;
 419         pdu->id = r_type;
 420         pdu->tag = r_tag;
 421
 422         P9_DPRINTK(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n", pdu->size,
 423                                                         pdu->id, pdu->tag);
 424
 425         if (type)
 426                 *type = r_type;
 427         if (tag)
 428                 *tag = r_tag;
 429         if (size)
 430                 *size = r_size;
 431
 432
 433 rewind_and_exit:
 434         if (rewind)
 435                 pdu->offset = offset;
 436         return err;
 437 }
 438 EXPORT_SYMBOL(p9_parse_header);
 439
 440 /**
 441  * p9_check_errors - check 9p packet for error return and process it
 442  * @c: current client instance
 443  * @req: request to parse and check for error conditions
 444  *
 445  * returns error code if one is discovered, otherwise returns 0
 446  *
 447  * this will have to be more complicated if we have multiple
 448  * error packet types
 449  */
 450
 451 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 452 {
 453         int8_t type;
 454         int err;
 455         int ecode;
 456
 457         err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
 458         if (err) {
 459                 P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
 460                 return err;
 461         }
 462
 463         if (type != P9_RERROR && type != P9_RLERROR)
 464                 return 0;
 465
 466         if (!p9_is_proto_dotl(c)) {
 467                 char *ename;
 468
 469                 if (req->tc->pbuf_size) {
 470                         /* Handle user buffers */
 471                         size_t len = req->rc->size - req->rc->offset;
 472                         if (req->tc->pubuf) {
 473                                 /* User Buffer */
 474                                 err = copy_from_user(
 475                                         &req->rc->sdata[req->rc->offset],
 476                                         req->tc->pubuf, len);
 477                                 if (err) {
 478                                         err = -EFAULT;
 479                                         goto out_err;
 480                                 }
 481                         } else {
 482                                 /* Kernel Buffer */
 483                                 memmove(&req->rc->sdata[req->rc->offset],
 484                                                 req->tc->pkbuf, len);
 485                         }
 486                 }
 487                 err = p9pdu_readf(req->rc, c->proto_version, "s?d",
 488                                 &ename, &ecode);
 489                 if (err)
 490                         goto out_err;
 491
 492                 if (p9_is_proto_dotu(c))
 493                         err = -ecode;
 494
 495                 if (!err || !IS_ERR_VALUE(err)) {
 496                         err = p9_errstr2errno(ename, strlen(ename));
 497
 498                         P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode,
 499                                         ename);
 500
 501                         kfree(ename);
 502                 }
 503         } else {
 504                 err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
 505                 err = -ecode;
 506
 507                 P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
 508         }
 509
 510
 511         return err;
 512
 513 out_err:
 514         P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
 515
 516         return err;
 517 }
 518
 519 static struct p9_req_t *
 520 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
 521
 522 /**
 523  * p9_client_flush - flush (cancel) a request
 524  * @c: client state
 525  * @oldreq: request to cancel
 526  *
 527  * This sents a flush for a particular request and links
 528  * the flush request to the original request.  The current
 529  * code only supports a single flush request although the protocol
 530  * allows for multiple flush requests to be sent for a single request.
 531  *
 532  */
 533
 534 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
 535 {
 536         struct p9_req_t *req;
 537         int16_t oldtag;
 538         int err;
 539
 540         err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
 541         if (err)
 542                 return err;
 543
 544         P9_DPRINTK(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
 545
 546         req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
 547         if (IS_ERR(req))
 548                 return PTR_ERR(req);
 549
 550
 551         /* if we haven't received a response for oldreq,
 552            remove it from the list. */
 553         spin_lock(&c->lock);
 554         if (oldreq->status == REQ_STATUS_FLSH)
 555                 list_del(&oldreq->req_list);
 556         spin_unlock(&c->lock);
 557
 558         p9_free_req(c, req);
 559         return 0;
 560 }
 561
 562 /**
 563  * p9_client_rpc - issue a request and wait for a response
 564  * @c: client session
 565  * @type: type of request
 566  * @fmt: protocol format string (see protocol.c)
 567  *
 568  * Returns request structure (which client must free using p9_free_req)
 569  */
 570
 571 static struct p9_req_t *
 572 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 573 {
 574         va_list ap;
 575         int tag, err;
 576         struct p9_req_t *req;
 577         unsigned long flags;
 578         int sigpending;
 579
 580         P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
 581
 582         /* we allow for any status other than disconnected */
 583         if (c->status == Disconnected)
 584                 return ERR_PTR(-EIO);
 585
 586         /* if status is begin_disconnected we allow only clunk request */
 587         if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
 588                 return ERR_PTR(-EIO);
 589
 590         if (signal_pending(current)) {
 591                 sigpending = 1;
 592                 clear_thread_flag(TIF_SIGPENDING);
 593         } else
 594                 sigpending = 0;
 595
 596         tag = P9_NOTAG;
 597         if (type != P9_TVERSION) {
 598                 tag = p9_idpool_get(c->tagpool);
 599                 if (tag < 0)
 600                         return ERR_PTR(-ENOMEM);
 601         }
 602
 603         req = p9_tag_alloc(c, tag);
 604         if (IS_ERR(req))
 605                 return req;
 606
 607         /* marshall the data */
 608         p9pdu_prepare(req->tc, tag, type);
 609         va_start(ap, fmt);
 610         err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
 611         va_end(ap);
 612         if (err)
 613                 goto reterr;
 614         p9pdu_finalize(req->tc);
 615
 616         err = c->trans_mod->request(c, req);
 617         if (err < 0) {
 618                 if (err != -ERESTARTSYS && err != -EFAULT)
 619                         c->status = Disconnected;
 620                 goto reterr;
 621         }
 622
 623         P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);
 624         err = wait_event_interruptible(*req->wq,
 625                                                 req->status >= REQ_STATUS_RCVD);
 626         P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",
 627                                                 req->wq, tag, err);
 628
 629         if (req->status == REQ_STATUS_ERROR) {
 630                 P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
 631                 err = req->t_err;
 632         }
 633
 634         if ((err == -ERESTARTSYS) && (c->status == Connected)) {
 635                 P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
 636                 sigpending = 1;
 637                 clear_thread_flag(TIF_SIGPENDING);
 638
 639                 if (c->trans_mod->cancel(c, req))
 640                         p9_client_flush(c, req);
 641
 642                 /* if we received the response anyway, don't signal error */
 643                 if (req->status == REQ_STATUS_RCVD)
 644                         err = 0;
 645         }
 646
 647         if (sigpending) {
 648                 spin_lock_irqsave(&current->sighand->siglock, flags);
 649                 recalc_sigpending();
 650                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 651         }
 652
 653         if (err < 0)
 654                 goto reterr;
 655
 656         err = p9_check_errors(c, req);
 657         if (!err) {
 658                 P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d\n", c, type);
 659                 return req;
 660         }
 661
 662 reterr:
 663         P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d error: %d\n", c, type,
 664                                                                         err);
 665         p9_free_req(c, req);
 666         return ERR_PTR(err);
 667 }
 668
 669 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 670 {
 671         int ret;
 672         struct p9_fid *fid;
 673         unsigned long flags;
 674
 675         P9_DPRINTK(P9_DEBUG_FID, "clnt %p\n", clnt);
 676         fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
 677         if (!fid)
 678                 return ERR_PTR(-ENOMEM);
 679
 680         ret = p9_idpool_get(clnt->fidpool);
 681         if (ret < 0) {
 682                 ret = -ENOSPC;
 683                 goto error;
 684         }
 685         fid->fid = ret;
 686
 687         memset(&fid->qid, 0, sizeof(struct p9_qid));
 688         fid->mode = -1;
 689         fid->uid = current_fsuid();
 690         fid->clnt = clnt;
 691         fid->rdir = NULL;
 692         spin_lock_irqsave(&clnt->lock, flags);
 693         list_add(&fid->flist, &clnt->fidlist);
 694         spin_unlock_irqrestore(&clnt->lock, flags);
 695
 696         return fid;
 697
 698 error:
 699         kfree(fid);
 700         return ERR_PTR(ret);
 701 }
 702
 703 static void p9_fid_destroy(struct p9_fid *fid)
 704 {
 705         struct p9_client *clnt;
 706         unsigned long flags;
 707
 708         P9_DPRINTK(P9_DEBUG_FID, "fid %d\n", fid->fid);
 709         clnt = fid->clnt;
 710         p9_idpool_put(fid->fid, clnt->fidpool);
 711         spin_lock_irqsave(&clnt->lock, flags);
 712         list_del(&fid->flist);
 713         spin_unlock_irqrestore(&clnt->lock, flags);
 714         kfree(fid->rdir);
 715         kfree(fid);
 716 }
 717
 718 static int p9_client_version(struct p9_client *c)
 719 {
 720         int err = 0;
 721         struct p9_req_t *req;
 722         char *version;
 723         int msize;
 724
 725         P9_DPRINTK(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
 726                                                 c->msize, c->proto_version);
 727
 728         switch (c->proto_version) {
 729         case p9_proto_2000L:
 730                 req = p9_client_rpc(c, P9_TVERSION, "ds",
 731                                         c->msize, "9P2000.L");
 732                 break;
 733         case p9_proto_2000u:
 734                 req = p9_client_rpc(c, P9_TVERSION, "ds",
 735                                         c->msize, "9P2000.u");
 736                 break;
 737         case p9_proto_legacy:
 738                 req = p9_client_rpc(c, P9_TVERSION, "ds",
 739                                         c->msize, "9P2000");
 740                 break;
 741         default:
 742                 return -EINVAL;
 743                 break;
 744         }
 745
 746         if (IS_ERR(req))
 747                 return PTR_ERR(req);
 748
 749         err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
 750         if (err) {
 751                 P9_DPRINTK(P9_DEBUG_9P, "version error %d\n", err);
 752                 p9pdu_dump(1, req->rc);
 753                 goto error;
 754         }
 755
 756         P9_DPRINTK(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
 757         if (!strncmp(version, "9P2000.L", 8))
 758                 c->proto_version = p9_proto_2000L;
 759         else if (!strncmp(version, "9P2000.u", 8))
 760                 c->proto_version = p9_proto_2000u;
 761         else if (!strncmp(version, "9P2000", 6))
 762                 c->proto_version = p9_proto_legacy;
 763         else {
 764                 err = -EREMOTEIO;
 765                 goto error;
 766         }
 767
 768         if (msize < c->msize)
 769                 c->msize = msize;
 770
 771 error:
 772         kfree(version);
 773         p9_free_req(c, req);
 774
 775         return err;
 776 }
 777
 778 struct p9_client *p9_client_create(const char *dev_name, char *options)
 779 {
 780         int err;
 781         struct p9_client *clnt;
 782
 783         err = 0;
 784         clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
 785         if (!clnt)
 786                 return ERR_PTR(-ENOMEM);
 787
 788         clnt->trans_mod = NULL;
 789         clnt->trans = NULL;
 790         spin_lock_init(&clnt->lock);
 791         INIT_LIST_HEAD(&clnt->fidlist);
 792
 793         err = p9_tag_init(clnt);
 794         if (err < 0)
 795                 goto free_client;
 796
 797         err = parse_opts(options, clnt);
 798         if (err < 0)
 799                 goto destroy_tagpool;
 800
 801         if (!clnt->trans_mod)
 802                 clnt->trans_mod = v9fs_get_default_trans();
 803
 804         if (clnt->trans_mod == NULL) {
 805                 err = -EPROTONOSUPPORT;
 806                 P9_DPRINTK(P9_DEBUG_ERROR,
 807                                 "No transport defined or default transport\n");
 808                 goto destroy_tagpool;
 809         }
 810
 811         clnt->fidpool = p9_idpool_create();
 812         if (IS_ERR(clnt->fidpool)) {
 813                 err = PTR_ERR(clnt->fidpool);
 814                 goto put_trans;
 815         }
 816
 817         P9_DPRINTK(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
 818                 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
 819
 820         err = clnt->trans_mod->create(clnt, dev_name, options);
 821         if (err)
 822                 goto destroy_fidpool;
 823
 824         if ((clnt->msize+P9_IOHDRSZ) > clnt->trans_mod->maxsize)
 825                 clnt->msize = clnt->trans_mod->maxsize-P9_IOHDRSZ;
 826
 827         err = p9_client_version(clnt);
 828         if (err)
 829                 goto close_trans;
 830
 831         return clnt;
 832
 833 close_trans:
 834         clnt->trans_mod->close(clnt);
 835 destroy_fidpool:
 836         p9_idpool_destroy(clnt->fidpool);
 837 put_trans:
 838         v9fs_put_trans(clnt->trans_mod);
 839 destroy_tagpool:
 840         p9_idpool_destroy(clnt->tagpool);
 841 free_client:
 842         kfree(clnt);
 843         return ERR_PTR(err);
 844 }
 845 EXPORT_SYMBOL(p9_client_create);
 846
 847 void p9_client_destroy(struct p9_client *clnt)
 848 {
 849         struct p9_fid *fid, *fidptr;
 850
 851         P9_DPRINTK(P9_DEBUG_MUX, "clnt %p\n", clnt);
 852
 853         if (clnt->trans_mod)
 854                 clnt->trans_mod->close(clnt);
 855
 856         v9fs_put_trans(clnt->trans_mod);
 857
 858         list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
 859                 printk(KERN_INFO "Found fid %d not clunked\n", fid->fid);
 860                 p9_fid_destroy(fid);
 861         }
 862
 863         if (clnt->fidpool)
 864                 p9_idpool_destroy(clnt->fidpool);
 865
 866         p9_tag_cleanup(clnt);
 867
 868         kfree(clnt);
 869 }
 870 EXPORT_SYMBOL(p9_client_destroy);
 871
 872 void p9_client_disconnect(struct p9_client *clnt)
 873 {
 874         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
 875         clnt->status = Disconnected;
 876 }
 877 EXPORT_SYMBOL(p9_client_disconnect);
 878
 879 void p9_client_begin_disconnect(struct p9_client *clnt)
 880 {
 881         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
 882         clnt->status = BeginDisconnect;
 883 }
 884 EXPORT_SYMBOL(p9_client_begin_disconnect);
 885
 886 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 887         char *uname, u32 n_uname, char *aname)
 888 {
 889         int err;
 890         struct p9_req_t *req;
 891         struct p9_fid *fid;
 892         struct p9_qid qid;
 893
 894         P9_DPRINTK(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
 895                                         afid ? afid->fid : -1, uname, aname);
 896         err = 0;
 897
 898         fid = p9_fid_create(clnt);
 899         if (IS_ERR(fid)) {
 900                 err = PTR_ERR(fid);
 901                 fid = NULL;
 902                 goto error;
 903         }
 904
 905         req = p9_client_rpc(clnt, P9_TATTACH, "ddss?d", fid->fid,
 906                         afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
 907         if (IS_ERR(req)) {
 908                 err = PTR_ERR(req);
 909                 goto error;
 910         }
 911
 912         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
 913         if (err) {
 914                 p9pdu_dump(1, req->rc);
 915                 p9_free_req(clnt, req);
 916                 goto error;
 917         }
 918
 919         P9_DPRINTK(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
 920                                         qid.type,
 921                                         (unsigned long long)qid.path,
 922                                         qid.version);
 923
 924         memmove(&fid->qid, &qid, sizeof(struct p9_qid));
 925
 926         p9_free_req(clnt, req);
 927         return fid;
 928
 929 error:
 930         if (fid)
 931                 p9_fid_destroy(fid);
 932         return ERR_PTR(err);
 933 }
 934 EXPORT_SYMBOL(p9_client_attach);
 935
 936 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 937                 char **wnames, int clone)
 938 {
 939         int err;
 940         struct p9_client *clnt;
 941         struct p9_fid *fid;
 942         struct p9_qid *wqids;
 943         struct p9_req_t *req;
 944         uint16_t nwqids, count;
 945
 946         err = 0;
 947         wqids = NULL;
 948         clnt = oldfid->clnt;
 949         if (clone) {
 950                 fid = p9_fid_create(clnt);
 951                 if (IS_ERR(fid)) {
 952                         err = PTR_ERR(fid);
 953                         fid = NULL;
 954                         goto error;
 955                 }
 956
 957                 fid->uid = oldfid->uid;
 958         } else
 959                 fid = oldfid;
 960
 961
 962         P9_DPRINTK(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
 963                 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
 964
 965         req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
 966                                                                 nwname, wnames);
 967         if (IS_ERR(req)) {
 968                 err = PTR_ERR(req);
 969                 goto error;
 970         }
 971
 972         err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
 973         if (err) {
 974                 p9pdu_dump(1, req->rc);
 975                 p9_free_req(clnt, req);
 976                 goto clunk_fid;
 977         }
 978         p9_free_req(clnt, req);
 979
 980         P9_DPRINTK(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
 981
 982         if (nwqids != nwname) {
 983                 err = -ENOENT;
 984                 goto clunk_fid;
 985         }
 986
 987         for (count = 0; count < nwqids; count++)
 988                 P9_DPRINTK(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
 989                         count, wqids[count].type,
 990                         (unsigned long long)wqids[count].path,
 991                         wqids[count].version);
 992
 993         if (nwname)
 994                 memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
 995         else
 996                 fid->qid = oldfid->qid;
 997
 998         kfree(wqids);
 999         return fid;
1000
1001 clunk_fid:
1002         kfree(wqids);
1003         p9_client_clunk(fid);
1004         fid = NULL;
1005
1006 error:
1007         if (fid && (fid != oldfid))
1008                 p9_fid_destroy(fid);
1009
1010         return ERR_PTR(err);
1011 }
1012 EXPORT_SYMBOL(p9_client_walk);
1013
1014 int p9_client_open(struct p9_fid *fid, int mode)
1015 {
1016         int err;
1017         struct p9_client *clnt;
1018         struct p9_req_t *req;
1019         struct p9_qid qid;
1020         int iounit;
1021
1022         clnt = fid->clnt;
1023         P9_DPRINTK(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1024                 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1025         err = 0;
1026
1027         if (fid->mode != -1)
1028                 return -EINVAL;
1029
1030         if (p9_is_proto_dotl(clnt))
1031                 req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1032         else
1033                 req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1034         if (IS_ERR(req)) {
1035                 err = PTR_ERR(req);
1036                 goto error;
1037         }
1038
1039         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1040         if (err) {
1041                 p9pdu_dump(1, req->rc);
1042                 goto free_and_error;
1043         }
1044
1045         P9_DPRINTK(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1046                 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1047                 (unsigned long long)qid.path, qid.version, iounit);
1048
1049         fid->mode = mode;
1050         fid->iounit = iounit;
1051
1052 free_and_error:
1053         p9_free_req(clnt, req);
1054 error:
1055         return err;
1056 }
1057 EXPORT_SYMBOL(p9_client_open);
1058
1059 int p9_client_create_dotl(struct p9_fid *ofid, char *name, u32 flags, u32 mode,
1060                 gid_t gid, struct p9_qid *qid)
1061 {
1062         int err = 0;
1063         struct p9_client *clnt;
1064         struct p9_req_t *req;
1065         int iounit;
1066
1067         P9_DPRINTK(P9_DEBUG_9P,
1068                         ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1069                         ofid->fid, name, flags, mode, gid);
1070         clnt = ofid->clnt;
1071
1072         if (ofid->mode != -1)
1073                 return -EINVAL;
1074
1075         req = p9_client_rpc(clnt, P9_TLCREATE, "dsddd", ofid->fid, name, flags,
1076                         mode, gid);
1077         if (IS_ERR(req)) {
1078                 err = PTR_ERR(req);
1079                 goto error;
1080         }
1081
1082         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
1083         if (err) {
1084                 p9pdu_dump(1, req->rc);
1085                 goto free_and_error;
1086         }
1087
1088         P9_DPRINTK(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1089                         qid->type,
1090                         (unsigned long long)qid->path,
1091                         qid->version, iounit);
1092
1093         ofid->mode = mode;
1094         ofid->iounit = iounit;
1095
1096 free_and_error:
1097         p9_free_req(clnt, req);
1098 error:
1099         return err;
1100 }
1101 EXPORT_SYMBOL(p9_client_create_dotl);
1102
1103 int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
1104                      char *extension)
1105 {
1106         int err;
1107         struct p9_client *clnt;
1108         struct p9_req_t *req;
1109         struct p9_qid qid;
1110         int iounit;
1111
1112         P9_DPRINTK(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1113                                                 fid->fid, name, perm, mode);
1114         err = 0;
1115         clnt = fid->clnt;
1116
1117         if (fid->mode != -1)
1118                 return -EINVAL;
1119
1120         req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1121                                 mode, extension);
1122         if (IS_ERR(req)) {
1123                 err = PTR_ERR(req);
1124                 goto error;
1125         }
1126
1127         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1128         if (err) {
1129                 p9pdu_dump(1, req->rc);
1130                 goto free_and_error;
1131         }
1132
1133         P9_DPRINTK(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1134                                 qid.type,
1135                                 (unsigned long long)qid.path,
1136                                 qid.version, iounit);
1137
1138         fid->mode = mode;
1139         fid->iounit = iounit;
1140
1141 free_and_error:
1142         p9_free_req(clnt, req);
1143 error:
1144         return err;
1145 }
1146 EXPORT_SYMBOL(p9_client_fcreate);
1147
1148 int p9_client_symlink(struct p9_fid *dfid, char *name, char *symtgt, gid_t gid,
1149                 struct p9_qid *qid)
1150 {
1151         int err = 0;
1152         struct p9_client *clnt;
1153         struct p9_req_t *req;
1154
1155         P9_DPRINTK(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1156                         dfid->fid, name, symtgt);
1157         clnt = dfid->clnt;
1158
1159         req = p9_client_rpc(clnt, P9_TSYMLINK, "dssd", dfid->fid, name, symtgt,
1160                         gid);
1161         if (IS_ERR(req)) {
1162                 err = PTR_ERR(req);
1163                 goto error;
1164         }
1165
1166         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1167         if (err) {
1168                 p9pdu_dump(1, req->rc);
1169                 goto free_and_error;
1170         }
1171
1172         P9_DPRINTK(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1173                         qid->type, (unsigned long long)qid->path, qid->version);
1174
1175 free_and_error:
1176         p9_free_req(clnt, req);
1177 error:
1178         return err;
1179 }
1180 EXPORT_SYMBOL(p9_client_symlink);
1181
1182 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, char *newname)
1183 {
1184         struct p9_client *clnt;
1185         struct p9_req_t *req;
1186
1187         P9_DPRINTK(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1188                         dfid->fid, oldfid->fid, newname);
1189         clnt = dfid->clnt;
1190         req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1191                         newname);
1192         if (IS_ERR(req))
1193                 return PTR_ERR(req);
1194
1195         P9_DPRINTK(P9_DEBUG_9P, "<<< RLINK\n");
1196         p9_free_req(clnt, req);
1197         return 0;
1198 }
1199 EXPORT_SYMBOL(p9_client_link);
1200
1201 int p9_client_fsync(struct p9_fid *fid, int datasync)
1202 {
1203         int err;
1204         struct p9_client *clnt;
1205         struct p9_req_t *req;
1206
1207         P9_DPRINTK(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1208                         fid->fid, datasync);
1209         err = 0;
1210         clnt = fid->clnt;
1211
1212         req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1213         if (IS_ERR(req)) {
1214                 err = PTR_ERR(req);
1215                 goto error;
1216         }
1217
1218         P9_DPRINTK(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1219
1220         p9_free_req(clnt, req);
1221
1222 error:
1223         return err;
1224 }
1225 EXPORT_SYMBOL(p9_client_fsync);
1226
1227 int p9_client_clunk(struct p9_fid *fid)
1228 {
1229         int err;
1230         struct p9_client *clnt;
1231         struct p9_req_t *req;
1232
1233         if (!fid) {
1234                 P9_EPRINTK(KERN_WARNING, "Trying to clunk with NULL fid\n");
1235                 dump_stack();
1236                 return 0;
1237         }
1238
1239         P9_DPRINTK(P9_DEBUG_9P, ">>> TCLUNK fid %d\n", fid->fid);
1240         err = 0;
1241         clnt = fid->clnt;
1242
1243         req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1244         if (IS_ERR(req)) {
1245                 err = PTR_ERR(req);
1246                 goto error;
1247         }
1248
1249         P9_DPRINTK(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1250
1251         p9_free_req(clnt, req);
1252         p9_fid_destroy(fid);
1253
1254 error:
1255         return err;
1256 }
1257 EXPORT_SYMBOL(p9_client_clunk);
1258
1259 int p9_client_remove(struct p9_fid *fid)
1260 {
1261         int err;
1262         struct p9_client *clnt;
1263         struct p9_req_t *req;
1264
1265         P9_DPRINTK(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1266         err = 0;
1267         clnt = fid->clnt;
1268
1269         req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1270         if (IS_ERR(req)) {
1271                 err = PTR_ERR(req);
1272                 goto error;
1273         }
1274
1275         P9_DPRINTK(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1276
1277         p9_free_req(clnt, req);
1278 error:
1279         p9_fid_destroy(fid);
1280         return err;
1281 }
1282 EXPORT_SYMBOL(p9_client_remove);
1283
1284 int
1285 p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
1286                                                                 u32 count)
1287 {
1288         int err, rsize;
1289         struct p9_client *clnt;
1290         struct p9_req_t *req;
1291         char *dataptr;
1292
1293         P9_DPRINTK(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", fid->fid,
1294                                         (long long unsigned) offset, count);
1295         err = 0;
1296         clnt = fid->clnt;
1297
1298         rsize = fid->iounit;
1299         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1300                 rsize = clnt->msize - P9_IOHDRSZ;
1301
1302         if (count < rsize)
1303                 rsize = count;
1304
1305         /* Don't bother zerocopy for small IO (< 1024) */
1306         if (((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
1307                         P9_TRANS_PREF_PAYLOAD_SEP) && (rsize > 1024)) {
1308                 req = p9_client_rpc(clnt, P9_TREAD, "dqE", fid->fid, offset,
1309                                 rsize, data, udata);
1310         } else {
1311                 req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1312                                 rsize);
1313         }
1314         if (IS_ERR(req)) {
1315                 err = PTR_ERR(req);
1316                 goto error;
1317         }
1318
1319         err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
1320         if (err) {
1321                 p9pdu_dump(1, req->rc);
1322                 goto free_and_error;
1323         }
1324
1325         P9_DPRINTK(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1326
1327         if (!req->tc->pbuf_size) {
1328                 if (data) {
1329                         memmove(data, dataptr, count);
1330                 } else {
1331                         err = copy_to_user(udata, dataptr, count);
1332                         if (err) {
1333                                 err = -EFAULT;
1334                                 goto free_and_error;
1335                         }
1336                 }
1337         }
1338         p9_free_req(clnt, req);
1339         return count;
1340
1341 free_and_error:
1342         p9_free_req(clnt, req);
1343 error:
1344         return err;
1345 }
1346 EXPORT_SYMBOL(p9_client_read);
1347
1348 int
1349 p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
1350                                                         u64 offset, u32 count)
1351 {
1352         int err, rsize;
1353         struct p9_client *clnt;
1354         struct p9_req_t *req;
1355
1356         P9_DPRINTK(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
1357                                 fid->fid, (long long unsigned) offset, count);
1358         err = 0;
1359         clnt = fid->clnt;
1360
1361         rsize = fid->iounit;
1362         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1363                 rsize = clnt->msize - P9_IOHDRSZ;
1364
1365         if (count < rsize)
1366                 rsize = count;
1367
1368         /* Don't bother zerocopy form small IO (< 1024) */
1369         if (((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
1370                                 P9_TRANS_PREF_PAYLOAD_SEP) && (rsize > 1024)) {
1371                 req = p9_client_rpc(clnt, P9_TWRITE, "dqE", fid->fid, offset,
1372                                 rsize, data, udata);
1373         } else {
1374
1375                 if (data)
1376                         req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid,
1377                                         offset, rsize, data);
1378                 else
1379                         req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid,
1380                                         offset, rsize, udata);
1381         }
1382         if (IS_ERR(req)) {
1383                 err = PTR_ERR(req);
1384                 goto error;
1385         }
1386
1387         err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
1388         if (err) {
1389                 p9pdu_dump(1, req->rc);
1390                 goto free_and_error;
1391         }
1392
1393         P9_DPRINTK(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1394
1395         p9_free_req(clnt, req);
1396         return count;
1397
1398 free_and_error:
1399         p9_free_req(clnt, req);
1400 error:
1401         return err;
1402 }
1403 EXPORT_SYMBOL(p9_client_write);
1404
1405 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1406 {
1407         int err;
1408         struct p9_client *clnt;
1409         struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1410         struct p9_req_t *req;
1411         u16 ignored;
1412
1413         P9_DPRINTK(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1414
1415         if (!ret)
1416                 return ERR_PTR(-ENOMEM);
1417
1418         err = 0;
1419         clnt = fid->clnt;
1420
1421         req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1422         if (IS_ERR(req)) {
1423                 err = PTR_ERR(req);
1424                 goto error;
1425         }
1426
1427         err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
1428         if (err) {
1429                 p9pdu_dump(1, req->rc);
1430                 p9_free_req(clnt, req);
1431                 goto error;
1432         }
1433
1434         P9_DPRINTK(P9_DEBUG_9P,
1435                 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1436                 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1437                 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1438                 "<<<    uid=%d gid=%d n_muid=%d\n",
1439                 ret->size, ret->type, ret->dev, ret->qid.type,
1440                 (unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1441                 ret->atime, ret->mtime, (unsigned long long)ret->length,
1442                 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1443                 ret->n_uid, ret->n_gid, ret->n_muid);
1444
1445         p9_free_req(clnt, req);
1446         return ret;
1447
1448 error:
1449         kfree(ret);
1450         return ERR_PTR(err);
1451 }
1452 EXPORT_SYMBOL(p9_client_stat);
1453
1454 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1455                                                         u64 request_mask)
1456 {
1457         int err;
1458         struct p9_client *clnt;
1459         struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1460                                                                 GFP_KERNEL);
1461         struct p9_req_t *req;
1462
1463         P9_DPRINTK(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1464                                                         fid->fid, request_mask);
1465
1466         if (!ret)
1467                 return ERR_PTR(-ENOMEM);
1468
1469         err = 0;
1470         clnt = fid->clnt;
1471
1472         req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1473         if (IS_ERR(req)) {
1474                 err = PTR_ERR(req);
1475                 goto error;
1476         }
1477
1478         err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
1479         if (err) {
1480                 p9pdu_dump(1, req->rc);
1481                 p9_free_req(clnt, req);
1482                 goto error;
1483         }
1484
1485         P9_DPRINTK(P9_DEBUG_9P,
1486                 "<<< RGETATTR st_result_mask=%lld\n"
1487                 "<<< qid=%x.%llx.%x\n"
1488                 "<<< st_mode=%8.8x st_nlink=%llu\n"
1489                 "<<< st_uid=%d st_gid=%d\n"
1490                 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1491                 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1492                 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1493                 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1494                 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1495                 "<<< st_gen=%lld st_data_version=%lld",
1496                 ret->st_result_mask, ret->qid.type, ret->qid.path,
1497                 ret->qid.version, ret->st_mode, ret->st_nlink, ret->st_uid,
1498                 ret->st_gid, ret->st_rdev, ret->st_size, ret->st_blksize,
1499                 ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1500                 ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1501                 ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1502                 ret->st_gen, ret->st_data_version);
1503
1504         p9_free_req(clnt, req);
1505         return ret;
1506
1507 error:
1508         kfree(ret);
1509         return ERR_PTR(err);
1510 }
1511 EXPORT_SYMBOL(p9_client_getattr_dotl);
1512
1513 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1514 {
1515         int ret;
1516
1517         /* NOTE: size shouldn't include its own length */
1518         /* size[2] type[2] dev[4] qid[13] */
1519         /* mode[4] atime[4] mtime[4] length[8]*/
1520         /* name[s] uid[s] gid[s] muid[s] */
1521         ret = 2+4+13+4+4+4+8+2+2+2+2;
1522
1523         if (wst->name)
1524                 ret += strlen(wst->name);
1525         if (wst->uid)
1526                 ret += strlen(wst->uid);
1527         if (wst->gid)
1528                 ret += strlen(wst->gid);
1529         if (wst->muid)
1530                 ret += strlen(wst->muid);
1531
1532         if ((proto_version == p9_proto_2000u) ||
1533                 (proto_version == p9_proto_2000L)) {
1534                 ret += 2+4+4+4; /* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1535                 if (wst->extension)
1536                         ret += strlen(wst->extension);
1537         }
1538
1539         return ret;
1540 }
1541
1542 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1543 {
1544         int err;
1545         struct p9_req_t *req;
1546         struct p9_client *clnt;
1547
1548         err = 0;
1549         clnt = fid->clnt;
1550         wst->size = p9_client_statsize(wst, clnt->proto_version);
1551         P9_DPRINTK(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1552         P9_DPRINTK(P9_DEBUG_9P,
1553                 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1554                 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1555                 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1556                 "     uid=%d gid=%d n_muid=%d\n",
1557                 wst->size, wst->type, wst->dev, wst->qid.type,
1558                 (unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1559                 wst->atime, wst->mtime, (unsigned long long)wst->length,
1560                 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1561                 wst->n_uid, wst->n_gid, wst->n_muid);
1562
1563         req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1564         if (IS_ERR(req)) {
1565                 err = PTR_ERR(req);
1566                 goto error;
1567         }
1568
1569         P9_DPRINTK(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1570
1571         p9_free_req(clnt, req);
1572 error:
1573         return err;
1574 }
1575 EXPORT_SYMBOL(p9_client_wstat);
1576
1577 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1578 {
1579         int err;
1580         struct p9_req_t *req;
1581         struct p9_client *clnt;
1582
1583         err = 0;
1584         clnt = fid->clnt;
1585         P9_DPRINTK(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1586         P9_DPRINTK(P9_DEBUG_9P,
1587                 "    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1588                 "    atime_sec=%lld atime_nsec=%lld\n"
1589                 "    mtime_sec=%lld mtime_nsec=%lld\n",
1590                 p9attr->valid, p9attr->mode, p9attr->uid, p9attr->gid,
1591                 p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1592                 p9attr->mtime_sec, p9attr->mtime_nsec);
1593
1594         req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1595
1596         if (IS_ERR(req)) {
1597                 err = PTR_ERR(req);
1598                 goto error;
1599         }
1600         P9_DPRINTK(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1601         p9_free_req(clnt, req);
1602 error:
1603         return err;
1604 }
1605 EXPORT_SYMBOL(p9_client_setattr);
1606
1607 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1608 {
1609         int err;
1610         struct p9_req_t *req;
1611         struct p9_client *clnt;
1612
1613         err = 0;
1614         clnt = fid->clnt;
1615
1616         P9_DPRINTK(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1617
1618         req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1619         if (IS_ERR(req)) {
1620                 err = PTR_ERR(req);
1621                 goto error;
1622         }
1623
1624         err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1625                 &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1626                 &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1627         if (err) {
1628                 p9pdu_dump(1, req->rc);
1629                 p9_free_req(clnt, req);
1630                 goto error;
1631         }
1632
1633         P9_DPRINTK(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1634                 "blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1635                 "fsid %llu namelen %ld\n",
1636                 fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1637                 sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1638                 sb->fsid, (long int)sb->namelen);
1639
1640         p9_free_req(clnt, req);
1641 error:
1642         return err;
1643 }
1644 EXPORT_SYMBOL(p9_client_statfs);
1645
1646 int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid, char *name)
1647 {
1648         int err;
1649         struct p9_req_t *req;
1650         struct p9_client *clnt;
1651
1652         err = 0;
1653         clnt = fid->clnt;
1654
1655         P9_DPRINTK(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1656                         fid->fid, newdirfid->fid, name);
1657
1658         req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1659                         newdirfid->fid, name);
1660         if (IS_ERR(req)) {
1661                 err = PTR_ERR(req);
1662                 goto error;
1663         }
1664
1665         P9_DPRINTK(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1666
1667         p9_free_req(clnt, req);
1668 error:
1669         return err;
1670 }
1671 EXPORT_SYMBOL(p9_client_rename);
1672
1673 /*
1674  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1675  */
1676 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1677                                 const char *attr_name, u64 *attr_size)
1678 {
1679         int err;
1680         struct p9_req_t *req;
1681         struct p9_client *clnt;
1682         struct p9_fid *attr_fid;
1683
1684         err = 0;
1685         clnt = file_fid->clnt;
1686         attr_fid = p9_fid_create(clnt);
1687         if (IS_ERR(attr_fid)) {
1688                 err = PTR_ERR(attr_fid);
1689                 attr_fid = NULL;
1690                 goto error;
1691         }
1692         P9_DPRINTK(P9_DEBUG_9P,
1693                 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1694                 file_fid->fid, attr_fid->fid, attr_name);
1695
1696         req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1697                         file_fid->fid, attr_fid->fid, attr_name);
1698         if (IS_ERR(req)) {
1699                 err = PTR_ERR(req);
1700                 goto error;
1701         }
1702         err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
1703         if (err) {
1704                 p9pdu_dump(1, req->rc);
1705                 p9_free_req(clnt, req);
1706                 goto clunk_fid;
1707         }
1708         p9_free_req(clnt, req);
1709         P9_DPRINTK(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
1710                 attr_fid->fid, *attr_size);
1711         return attr_fid;
1712 clunk_fid:
1713         p9_client_clunk(attr_fid);
1714         attr_fid = NULL;
1715 error:
1716         if (attr_fid && (attr_fid != file_fid))
1717                 p9_fid_destroy(attr_fid);
1718
1719         return ERR_PTR(err);
1720 }
1721 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
1722
1723 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
1724                         u64 attr_size, int flags)
1725 {
1726         int err;
1727         struct p9_req_t *req;
1728         struct p9_client *clnt;
1729
1730         P9_DPRINTK(P9_DEBUG_9P,
1731                 ">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
1732                 fid->fid, name, (long long)attr_size, flags);
1733         err = 0;
1734         clnt = fid->clnt;
1735         req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
1736                         fid->fid, name, attr_size, flags);
1737         if (IS_ERR(req)) {
1738                 err = PTR_ERR(req);
1739                 goto error;
1740         }
1741         P9_DPRINTK(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
1742         p9_free_req(clnt, req);
1743 error:
1744         return err;
1745 }
1746 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
1747
1748 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
1749 {
1750         int err, rsize;
1751         struct p9_client *clnt;
1752         struct p9_req_t *req;
1753         char *dataptr;
1754
1755         P9_DPRINTK(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
1756                                 fid->fid, (long long unsigned) offset, count);
1757
1758         err = 0;
1759         clnt = fid->clnt;
1760
1761         rsize = fid->iounit;
1762         if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
1763                 rsize = clnt->msize - P9_READDIRHDRSZ;
1764
1765         if (count < rsize)
1766                 rsize = count;
1767
1768         if ((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
1769                         P9_TRANS_PREF_PAYLOAD_SEP) {
1770                 req = p9_client_rpc(clnt, P9_TREADDIR, "dqF", fid->fid,
1771                                 offset, rsize, data);
1772         } else {
1773                 req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
1774                                 offset, rsize);
1775         }
1776         if (IS_ERR(req)) {
1777                 err = PTR_ERR(req);
1778                 goto error;
1779         }
1780
1781         err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
1782         if (err) {
1783                 p9pdu_dump(1, req->rc);
1784                 goto free_and_error;
1785         }
1786
1787         P9_DPRINTK(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
1788
1789         if (!req->tc->pbuf_size && data)
1790                 memmove(data, dataptr, count);
1791
1792         p9_free_req(clnt, req);
1793         return count;
1794
1795 free_and_error:
1796         p9_free_req(clnt, req);
1797 error:
1798         return err;
1799 }
1800 EXPORT_SYMBOL(p9_client_readdir);
1801
1802 int p9_client_mknod_dotl(struct p9_fid *fid, char *name, int mode,
1803                         dev_t rdev, gid_t gid, struct p9_qid *qid)
1804 {
1805         int err;
1806         struct p9_client *clnt;
1807         struct p9_req_t *req;
1808
1809         err = 0;
1810         clnt = fid->clnt;
1811         P9_DPRINTK(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
1812                 "minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
1813         req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddd", fid->fid, name, mode,
1814                 MAJOR(rdev), MINOR(rdev), gid);
1815         if (IS_ERR(req))
1816                 return PTR_ERR(req);
1817
1818         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1819         if (err) {
1820                 p9pdu_dump(1, req->rc);
1821                 goto error;
1822         }
1823         P9_DPRINTK(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
1824                                 (unsigned long long)qid->path, qid->version);
1825
1826 error:
1827         p9_free_req(clnt, req);
1828         return err;
1829
1830 }
1831 EXPORT_SYMBOL(p9_client_mknod_dotl);
1832
1833 int p9_client_mkdir_dotl(struct p9_fid *fid, char *name, int mode,
1834                                 gid_t gid, struct p9_qid *qid)
1835 {
1836         int err;
1837         struct p9_client *clnt;
1838         struct p9_req_t *req;
1839
1840         err = 0;
1841         clnt = fid->clnt;
1842         P9_DPRINTK(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
1843                  fid->fid, name, mode, gid);
1844         req = p9_client_rpc(clnt, P9_TMKDIR, "dsdd", fid->fid, name, mode,
1845                 gid);
1846         if (IS_ERR(req))
1847                 return PTR_ERR(req);
1848
1849         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1850         if (err) {
1851                 p9pdu_dump(1, req->rc);
1852                 goto error;
1853         }
1854         P9_DPRINTK(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
1855                                 (unsigned long long)qid->path, qid->version);
1856
1857 error:
1858         p9_free_req(clnt, req);
1859         return err;
1860
1861 }
1862 EXPORT_SYMBOL(p9_client_mkdir_dotl);
1863
1864 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
1865 {
1866         int err;
1867         struct p9_client *clnt;
1868         struct p9_req_t *req;
1869
1870         err = 0;
1871         clnt = fid->clnt;
1872         P9_DPRINTK(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
1873                         "start %lld length %lld proc_id %d client_id %s\n",
1874                         fid->fid, flock->type, flock->flags, flock->start,
1875                         flock->length, flock->proc_id, flock->client_id);
1876
1877         req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
1878                                 flock->flags, flock->start, flock->length,
1879                                         flock->proc_id, flock->client_id);
1880
1881         if (IS_ERR(req))
1882                 return PTR_ERR(req);
1883
1884         err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
1885         if (err) {
1886                 p9pdu_dump(1, req->rc);
1887                 goto error;
1888         }
1889         P9_DPRINTK(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
1890 error:
1891         p9_free_req(clnt, req);
1892         return err;
1893
1894 }
1895 EXPORT_SYMBOL(p9_client_lock_dotl);
1896
1897 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
1898 {
1899         int err;
1900         struct p9_client *clnt;
1901         struct p9_req_t *req;
1902
1903         err = 0;
1904         clnt = fid->clnt;
1905         P9_DPRINTK(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
1906                 "length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
1907                 glock->start, glock->length, glock->proc_id, glock->client_id);
1908
1909         req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
1910                 glock->start, glock->length, glock->proc_id, glock->client_id);
1911
1912         if (IS_ERR(req))
1913                 return PTR_ERR(req);
1914
1915         err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
1916                         &glock->start, &glock->length, &glock->proc_id,
1917                         &glock->client_id);
1918         if (err) {
1919                 p9pdu_dump(1, req->rc);
1920                 goto error;
1921         }
1922         P9_DPRINTK(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
1923                 "proc_id %d client_id %s\n", glock->type, glock->start,
1924                 glock->length, glock->proc_id, glock->client_id);
1925 error:
1926         p9_free_req(clnt, req);
1927         return err;
1928 }
1929 EXPORT_SYMBOL(p9_client_getlock_dotl);
1930
1931 int p9_client_readlink(struct p9_fid *fid, char **target)
1932 {
1933         int err;
1934         struct p9_client *clnt;
1935         struct p9_req_t *req;
1936
1937         err = 0;
1938         clnt = fid->clnt;
1939         P9_DPRINTK(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
1940
1941         req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
1942         if (IS_ERR(req))
1943                 return PTR_ERR(req);
1944
1945         err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
1946         if (err) {
1947                 p9pdu_dump(1, req->rc);
1948                 goto error;
1949         }
1950         P9_DPRINTK(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
1951 error:
1952         p9_free_req(clnt, req);
1953         return err;
1954 }
1955 EXPORT_SYMBOL(p9_client_readlink);