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         if(tag >= c->max_tag)
 284                 return NULL;
 285
 286         row = tag / P9_ROW_MAXTAG;
 287         col = tag % P9_ROW_MAXTAG;
 288
 289         return &c->reqs[row][col];
 290 }
 291 EXPORT_SYMBOL(p9_tag_lookup);
 292
 293 /**
 294  * p9_tag_init - setup tags structure and contents
 295  * @c:  v9fs client struct
 296  *
 297  * This initializes the tags structure for each client instance.
 298  *
 299  */
 300
 301 static int p9_tag_init(struct p9_client *c)
 302 {
 303         int err = 0;
 304
 305         c->tagpool = p9_idpool_create();
 306         if (IS_ERR(c->tagpool)) {
 307                 err = PTR_ERR(c->tagpool);
 308                 goto error;
 309         }
 310         err = p9_idpool_get(c->tagpool); /* reserve tag 0 */
 311         if (err < 0) {
 312                 p9_idpool_destroy(c->tagpool);
 313                 goto error;
 314         }
 315         c->max_tag = 0;
 316 error:
 317         return err;
 318 }
 319
 320 /**
 321  * p9_tag_cleanup - cleans up tags structure and reclaims resources
 322  * @c:  v9fs client struct
 323  *
 324  * This frees resources associated with the tags structure
 325  *
 326  */
 327 static void p9_tag_cleanup(struct p9_client *c)
 328 {
 329         int row, col;
 330
 331         /* check to insure all requests are idle */
 332         for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
 333                 for (col = 0; col < P9_ROW_MAXTAG; col++) {
 334                         if (c->reqs[row][col].status != REQ_STATUS_IDLE) {
 335                                 P9_DPRINTK(P9_DEBUG_MUX,
 336                                   "Attempting to cleanup non-free tag %d,%d\n",
 337                                   row, col);
 338                                 /* TODO: delay execution of cleanup */
 339                                 return;
 340                         }
 341                 }
 342         }
 343
 344         if (c->tagpool) {
 345                 p9_idpool_put(0, c->tagpool); /* free reserved tag 0 */
 346                 p9_idpool_destroy(c->tagpool);
 347         }
 348
 349         /* free requests associated with tags */
 350         for (row = 0; row < (c->max_tag/P9_ROW_MAXTAG); row++) {
 351                 for (col = 0; col < P9_ROW_MAXTAG; col++) {
 352                         kfree(c->reqs[row][col].wq);
 353                         kfree(c->reqs[row][col].tc);
 354                         kfree(c->reqs[row][col].rc);
 355                 }
 356                 kfree(c->reqs[row]);
 357         }
 358         c->max_tag = 0;
 359 }
 360
 361 /**
 362  * p9_free_req - free a request and clean-up as necessary
 363  * c: client state
 364  * r: request to release
 365  *
 366  */
 367
 368 static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
 369 {
 370         int tag = r->tc->tag;
 371         P9_DPRINTK(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
 372
 373         r->status = REQ_STATUS_IDLE;
 374         if (tag != P9_NOTAG && p9_idpool_check(tag, c->tagpool))
 375                 p9_idpool_put(tag, c->tagpool);
 376 }
 377
 378 /**
 379  * p9_client_cb - call back from transport to client
 380  * c: client state
 381  * req: request received
 382  *
 383  */
 384 void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
 385 {
 386         P9_DPRINTK(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
 387         wake_up(req->wq);
 388         P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
 389 }
 390 EXPORT_SYMBOL(p9_client_cb);
 391
 392 /**
 393  * p9_parse_header - parse header arguments out of a packet
 394  * @pdu: packet to parse
 395  * @size: size of packet
 396  * @type: type of request
 397  * @tag: tag of packet
 398  * @rewind: set if we need to rewind offset afterwards
 399  */
 400
 401 int
 402 p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type, int16_t *tag,
 403                                                                 int rewind)
 404 {
 405         int8_t r_type;
 406         int16_t r_tag;
 407         int32_t r_size;
 408         int offset = pdu->offset;
 409         int err;
 410
 411         pdu->offset = 0;
 412         if (pdu->size == 0)
 413                 pdu->size = 7;
 414
 415         err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
 416         if (err)
 417                 goto rewind_and_exit;
 418
 419         pdu->size = r_size;
 420         pdu->id = r_type;
 421         pdu->tag = r_tag;
 422
 423         P9_DPRINTK(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n", pdu->size,
 424                                                         pdu->id, pdu->tag);
 425
 426         if (type)
 427                 *type = r_type;
 428         if (tag)
 429                 *tag = r_tag;
 430         if (size)
 431                 *size = r_size;
 432
 433
 434 rewind_and_exit:
 435         if (rewind)
 436                 pdu->offset = offset;
 437         return err;
 438 }
 439 EXPORT_SYMBOL(p9_parse_header);
 440
 441 /**
 442  * p9_check_errors - check 9p packet for error return and process it
 443  * @c: current client instance
 444  * @req: request to parse and check for error conditions
 445  *
 446  * returns error code if one is discovered, otherwise returns 0
 447  *
 448  * this will have to be more complicated if we have multiple
 449  * error packet types
 450  */
 451
 452 static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 453 {
 454         int8_t type;
 455         int err;
 456         int ecode;
 457
 458         err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
 459         if (err) {
 460                 P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
 461                 return err;
 462         }
 463
 464         if (type != P9_RERROR && type != P9_RLERROR)
 465                 return 0;
 466
 467         if (!p9_is_proto_dotl(c)) {
 468                 char *ename;
 469
 470                 if (req->tc->pbuf_size) {
 471                         /* Handle user buffers */
 472                         size_t len = req->rc->size - req->rc->offset;
 473                         if (req->tc->pubuf) {
 474                                 /* User Buffer */
 475                                 err = copy_from_user(
 476                                         &req->rc->sdata[req->rc->offset],
 477                                         req->tc->pubuf, len);
 478                                 if (err) {
 479                                         err = -EFAULT;
 480                                         goto out_err;
 481                                 }
 482                         } else {
 483                                 /* Kernel Buffer */
 484                                 memmove(&req->rc->sdata[req->rc->offset],
 485                                                 req->tc->pkbuf, len);
 486                         }
 487                 }
 488                 err = p9pdu_readf(req->rc, c->proto_version, "s?d",
 489                                 &ename, &ecode);
 490                 if (err)
 491                         goto out_err;
 492
 493                 if (p9_is_proto_dotu(c))
 494                         err = -ecode;
 495
 496                 if (!err || !IS_ERR_VALUE(err)) {
 497                         err = p9_errstr2errno(ename, strlen(ename));
 498
 499                         P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode,
 500                                         ename);
 501
 502                         kfree(ename);
 503                 }
 504         } else {
 505                 err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
 506                 err = -ecode;
 507
 508                 P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
 509         }
 510
 511
 512         return err;
 513
 514 out_err:
 515         P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
 516
 517         return err;
 518 }
 519
 520 static struct p9_req_t *
 521 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
 522
 523 /**
 524  * p9_client_flush - flush (cancel) a request
 525  * @c: client state
 526  * @oldreq: request to cancel
 527  *
 528  * This sents a flush for a particular request and links
 529  * the flush request to the original request.  The current
 530  * code only supports a single flush request although the protocol
 531  * allows for multiple flush requests to be sent for a single request.
 532  *
 533  */
 534
 535 static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
 536 {
 537         struct p9_req_t *req;
 538         int16_t oldtag;
 539         int err;
 540
 541         err = p9_parse_header(oldreq->tc, NULL, NULL, &oldtag, 1);
 542         if (err)
 543                 return err;
 544
 545         P9_DPRINTK(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
 546
 547         req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
 548         if (IS_ERR(req))
 549                 return PTR_ERR(req);
 550
 551
 552         /* if we haven't received a response for oldreq,
 553            remove it from the list. */
 554         spin_lock(&c->lock);
 555         if (oldreq->status == REQ_STATUS_FLSH)
 556                 list_del(&oldreq->req_list);
 557         spin_unlock(&c->lock);
 558
 559         p9_free_req(c, req);
 560         return 0;
 561 }
 562
 563 /**
 564  * p9_client_rpc - issue a request and wait for a response
 565  * @c: client session
 566  * @type: type of request
 567  * @fmt: protocol format string (see protocol.c)
 568  *
 569  * Returns request structure (which client must free using p9_free_req)
 570  */
 571
 572 static struct p9_req_t *
 573 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 574 {
 575         va_list ap;
 576         int tag, err;
 577         struct p9_req_t *req;
 578         unsigned long flags;
 579         int sigpending;
 580
 581         P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
 582
 583         /* we allow for any status other than disconnected */
 584         if (c->status == Disconnected)
 585                 return ERR_PTR(-EIO);
 586
 587         /* if status is begin_disconnected we allow only clunk request */
 588         if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
 589                 return ERR_PTR(-EIO);
 590
 591         if (signal_pending(current)) {
 592                 sigpending = 1;
 593                 clear_thread_flag(TIF_SIGPENDING);
 594         } else
 595                 sigpending = 0;
 596
 597         tag = P9_NOTAG;
 598         if (type != P9_TVERSION) {
 599                 tag = p9_idpool_get(c->tagpool);
 600                 if (tag < 0)
 601                         return ERR_PTR(-ENOMEM);
 602         }
 603
 604         req = p9_tag_alloc(c, tag);
 605         if (IS_ERR(req))
 606                 return req;
 607
 608         /* marshall the data */
 609         p9pdu_prepare(req->tc, tag, type);
 610         va_start(ap, fmt);
 611         err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
 612         va_end(ap);
 613         if (err)
 614                 goto reterr;
 615         p9pdu_finalize(req->tc);
 616
 617         err = c->trans_mod->request(c, req);
 618         if (err < 0) {
 619                 if (err != -ERESTARTSYS && err != -EFAULT)
 620                         c->status = Disconnected;
 621                 goto reterr;
 622         }
 623
 624         P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);
 625         err = wait_event_interruptible(*req->wq,
 626                                                 req->status >= REQ_STATUS_RCVD);
 627         P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",
 628                                                 req->wq, tag, err);
 629
 630         if (req->status == REQ_STATUS_ERROR) {
 631                 P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
 632                 err = req->t_err;
 633         }
 634
 635         if ((err == -ERESTARTSYS) && (c->status == Connected)) {
 636                 P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
 637                 sigpending = 1;
 638                 clear_thread_flag(TIF_SIGPENDING);
 639
 640                 if (c->trans_mod->cancel(c, req))
 641                         p9_client_flush(c, req);
 642
 643                 /* if we received the response anyway, don't signal error */
 644                 if (req->status == REQ_STATUS_RCVD)
 645                         err = 0;
 646         }
 647
 648         if (sigpending) {
 649                 spin_lock_irqsave(&current->sighand->siglock, flags);
 650                 recalc_sigpending();
 651                 spin_unlock_irqrestore(&current->sighand->siglock, flags);
 652         }
 653
 654         if (err < 0)
 655                 goto reterr;
 656
 657         err = p9_check_errors(c, req);
 658         if (!err) {
 659                 P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d\n", c, type);
 660                 return req;
 661         }
 662
 663 reterr:
 664         P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d error: %d\n", c, type,
 665                                                                         err);
 666         p9_free_req(c, req);
 667         return ERR_PTR(err);
 668 }
 669
 670 static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 671 {
 672         int ret;
 673         struct p9_fid *fid;
 674         unsigned long flags;
 675
 676         P9_DPRINTK(P9_DEBUG_FID, "clnt %p\n", clnt);
 677         fid = kmalloc(sizeof(struct p9_fid), GFP_KERNEL);
 678         if (!fid)
 679                 return ERR_PTR(-ENOMEM);
 680
 681         ret = p9_idpool_get(clnt->fidpool);
 682         if (ret < 0) {
 683                 ret = -ENOSPC;
 684                 goto error;
 685         }
 686         fid->fid = ret;
 687
 688         memset(&fid->qid, 0, sizeof(struct p9_qid));
 689         fid->mode = -1;
 690         fid->uid = current_fsuid();
 691         fid->clnt = clnt;
 692         fid->rdir = NULL;
 693         spin_lock_irqsave(&clnt->lock, flags);
 694         list_add(&fid->flist, &clnt->fidlist);
 695         spin_unlock_irqrestore(&clnt->lock, flags);
 696
 697         return fid;
 698
 699 error:
 700         kfree(fid);
 701         return ERR_PTR(ret);
 702 }
 703
 704 static void p9_fid_destroy(struct p9_fid *fid)
 705 {
 706         struct p9_client *clnt;
 707         unsigned long flags;
 708
 709         P9_DPRINTK(P9_DEBUG_FID, "fid %d\n", fid->fid);
 710         clnt = fid->clnt;
 711         p9_idpool_put(fid->fid, clnt->fidpool);
 712         spin_lock_irqsave(&clnt->lock, flags);
 713         list_del(&fid->flist);
 714         spin_unlock_irqrestore(&clnt->lock, flags);
 715         kfree(fid->rdir);
 716         kfree(fid);
 717 }
 718
 719 static int p9_client_version(struct p9_client *c)
 720 {
 721         int err = 0;
 722         struct p9_req_t *req;
 723         char *version;
 724         int msize;
 725
 726         P9_DPRINTK(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
 727                                                 c->msize, c->proto_version);
 728
 729         switch (c->proto_version) {
 730         case p9_proto_2000L:
 731                 req = p9_client_rpc(c, P9_TVERSION, "ds",
 732                                         c->msize, "9P2000.L");
 733                 break;
 734         case p9_proto_2000u:
 735                 req = p9_client_rpc(c, P9_TVERSION, "ds",
 736                                         c->msize, "9P2000.u");
 737                 break;
 738         case p9_proto_legacy:
 739                 req = p9_client_rpc(c, P9_TVERSION, "ds",
 740                                         c->msize, "9P2000");
 741                 break;
 742         default:
 743                 return -EINVAL;
 744                 break;
 745         }
 746
 747         if (IS_ERR(req))
 748                 return PTR_ERR(req);
 749
 750         err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
 751         if (err) {
 752                 P9_DPRINTK(P9_DEBUG_9P, "version error %d\n", err);
 753                 p9pdu_dump(1, req->rc);
 754                 goto error;
 755         }
 756
 757         P9_DPRINTK(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
 758         if (!strncmp(version, "9P2000.L", 8))
 759                 c->proto_version = p9_proto_2000L;
 760         else if (!strncmp(version, "9P2000.u", 8))
 761                 c->proto_version = p9_proto_2000u;
 762         else if (!strncmp(version, "9P2000", 6))
 763                 c->proto_version = p9_proto_legacy;
 764         else {
 765                 err = -EREMOTEIO;
 766                 goto error;
 767         }
 768
 769         if (msize < c->msize)
 770                 c->msize = msize;
 771
 772 error:
 773         kfree(version);
 774         p9_free_req(c, req);
 775
 776         return err;
 777 }
 778
 779 struct p9_client *p9_client_create(const char *dev_name, char *options)
 780 {
 781         int err;
 782         struct p9_client *clnt;
 783
 784         err = 0;
 785         clnt = kmalloc(sizeof(struct p9_client), GFP_KERNEL);
 786         if (!clnt)
 787                 return ERR_PTR(-ENOMEM);
 788
 789         clnt->trans_mod = NULL;
 790         clnt->trans = NULL;
 791         spin_lock_init(&clnt->lock);
 792         INIT_LIST_HEAD(&clnt->fidlist);
 793
 794         err = p9_tag_init(clnt);
 795         if (err < 0)
 796                 goto free_client;
 797
 798         err = parse_opts(options, clnt);
 799         if (err < 0)
 800                 goto destroy_tagpool;
 801
 802         if (!clnt->trans_mod)
 803                 clnt->trans_mod = v9fs_get_default_trans();
 804
 805         if (clnt->trans_mod == NULL) {
 806                 err = -EPROTONOSUPPORT;
 807                 P9_DPRINTK(P9_DEBUG_ERROR,
 808                                 "No transport defined or default transport\n");
 809                 goto destroy_tagpool;
 810         }
 811
 812         clnt->fidpool = p9_idpool_create();
 813         if (IS_ERR(clnt->fidpool)) {
 814                 err = PTR_ERR(clnt->fidpool);
 815                 goto put_trans;
 816         }
 817
 818         P9_DPRINTK(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
 819                 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
 820
 821         err = clnt->trans_mod->create(clnt, dev_name, options);
 822         if (err)
 823                 goto destroy_fidpool;
 824
 825         if (clnt->msize > clnt->trans_mod->maxsize)
 826                 clnt->msize = clnt->trans_mod->maxsize;
 827
 828         err = p9_client_version(clnt);
 829         if (err)
 830                 goto close_trans;
 831
 832         return clnt;
 833
 834 close_trans:
 835         clnt->trans_mod->close(clnt);
 836 destroy_fidpool:
 837         p9_idpool_destroy(clnt->fidpool);
 838 put_trans:
 839         v9fs_put_trans(clnt->trans_mod);
 840 destroy_tagpool:
 841         p9_idpool_destroy(clnt->tagpool);
 842 free_client:
 843         kfree(clnt);
 844         return ERR_PTR(err);
 845 }
 846 EXPORT_SYMBOL(p9_client_create);
 847
 848 void p9_client_destroy(struct p9_client *clnt)
 849 {
 850         struct p9_fid *fid, *fidptr;
 851
 852         P9_DPRINTK(P9_DEBUG_MUX, "clnt %p\n", clnt);
 853
 854         if (clnt->trans_mod)
 855                 clnt->trans_mod->close(clnt);
 856
 857         v9fs_put_trans(clnt->trans_mod);
 858
 859         list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
 860                 printk(KERN_INFO "Found fid %d not clunked\n", fid->fid);
 861                 p9_fid_destroy(fid);
 862         }
 863
 864         if (clnt->fidpool)
 865                 p9_idpool_destroy(clnt->fidpool);
 866
 867         p9_tag_cleanup(clnt);
 868
 869         kfree(clnt);
 870 }
 871 EXPORT_SYMBOL(p9_client_destroy);
 872
 873 void p9_client_disconnect(struct p9_client *clnt)
 874 {
 875         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
 876         clnt->status = Disconnected;
 877 }
 878 EXPORT_SYMBOL(p9_client_disconnect);
 879
 880 void p9_client_begin_disconnect(struct p9_client *clnt)
 881 {
 882         P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
 883         clnt->status = BeginDisconnect;
 884 }
 885 EXPORT_SYMBOL(p9_client_begin_disconnect);
 886
 887 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 888         char *uname, u32 n_uname, char *aname)
 889 {
 890         int err;
 891         struct p9_req_t *req;
 892         struct p9_fid *fid;
 893         struct p9_qid qid;
 894
 895         P9_DPRINTK(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
 896                                         afid ? afid->fid : -1, uname, aname);
 897         err = 0;
 898
 899         fid = p9_fid_create(clnt);
 900         if (IS_ERR(fid)) {
 901                 err = PTR_ERR(fid);
 902                 fid = NULL;
 903                 goto error;
 904         }
 905
 906         req = p9_client_rpc(clnt, P9_TATTACH, "ddss?d", fid->fid,
 907                         afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
 908         if (IS_ERR(req)) {
 909                 err = PTR_ERR(req);
 910                 goto error;
 911         }
 912
 913         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
 914         if (err) {
 915                 p9pdu_dump(1, req->rc);
 916                 p9_free_req(clnt, req);
 917                 goto error;
 918         }
 919
 920         P9_DPRINTK(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
 921                                         qid.type,
 922                                         (unsigned long long)qid.path,
 923                                         qid.version);
 924
 925         memmove(&fid->qid, &qid, sizeof(struct p9_qid));
 926
 927         p9_free_req(clnt, req);
 928         return fid;
 929
 930 error:
 931         if (fid)
 932                 p9_fid_destroy(fid);
 933         return ERR_PTR(err);
 934 }
 935 EXPORT_SYMBOL(p9_client_attach);
 936
 937 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 938                 char **wnames, int clone)
 939 {
 940         int err;
 941         struct p9_client *clnt;
 942         struct p9_fid *fid;
 943         struct p9_qid *wqids;
 944         struct p9_req_t *req;
 945         uint16_t nwqids, count;
 946
 947         err = 0;
 948         wqids = NULL;
 949         clnt = oldfid->clnt;
 950         if (clone) {
 951                 fid = p9_fid_create(clnt);
 952                 if (IS_ERR(fid)) {
 953                         err = PTR_ERR(fid);
 954                         fid = NULL;
 955                         goto error;
 956                 }
 957
 958                 fid->uid = oldfid->uid;
 959         } else
 960                 fid = oldfid;
 961
 962
 963         P9_DPRINTK(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
 964                 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
 965
 966         req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
 967                                                                 nwname, wnames);
 968         if (IS_ERR(req)) {
 969                 err = PTR_ERR(req);
 970                 goto error;
 971         }
 972
 973         err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
 974         if (err) {
 975                 p9pdu_dump(1, req->rc);
 976                 p9_free_req(clnt, req);
 977                 goto clunk_fid;
 978         }
 979         p9_free_req(clnt, req);
 980
 981         P9_DPRINTK(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
 982
 983         if (nwqids != nwname) {
 984                 err = -ENOENT;
 985                 goto clunk_fid;
 986         }
 987
 988         for (count = 0; count < nwqids; count++)
 989                 P9_DPRINTK(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
 990                         count, wqids[count].type,
 991                         (unsigned long long)wqids[count].path,
 992                         wqids[count].version);
 993
 994         if (nwname)
 995                 memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
 996         else
 997                 fid->qid = oldfid->qid;
 998
 999         kfree(wqids);
1000         return fid;
1001
1002 clunk_fid:
1003         kfree(wqids);
1004         p9_client_clunk(fid);
1005         fid = NULL;
1006
1007 error:
1008         if (fid && (fid != oldfid))
1009                 p9_fid_destroy(fid);
1010
1011         return ERR_PTR(err);
1012 }
1013 EXPORT_SYMBOL(p9_client_walk);
1014
1015 int p9_client_open(struct p9_fid *fid, int mode)
1016 {
1017         int err;
1018         struct p9_client *clnt;
1019         struct p9_req_t *req;
1020         struct p9_qid qid;
1021         int iounit;
1022
1023         clnt = fid->clnt;
1024         P9_DPRINTK(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
1025                 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
1026         err = 0;
1027
1028         if (fid->mode != -1)
1029                 return -EINVAL;
1030
1031         if (p9_is_proto_dotl(clnt))
1032                 req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
1033         else
1034                 req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
1035         if (IS_ERR(req)) {
1036                 err = PTR_ERR(req);
1037                 goto error;
1038         }
1039
1040         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1041         if (err) {
1042                 p9pdu_dump(1, req->rc);
1043                 goto free_and_error;
1044         }
1045
1046         P9_DPRINTK(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
1047                 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
1048                 (unsigned long long)qid.path, qid.version, iounit);
1049
1050         fid->mode = mode;
1051         fid->iounit = iounit;
1052
1053 free_and_error:
1054         p9_free_req(clnt, req);
1055 error:
1056         return err;
1057 }
1058 EXPORT_SYMBOL(p9_client_open);
1059
1060 int p9_client_create_dotl(struct p9_fid *ofid, char *name, u32 flags, u32 mode,
1061                 gid_t gid, struct p9_qid *qid)
1062 {
1063         int err = 0;
1064         struct p9_client *clnt;
1065         struct p9_req_t *req;
1066         int iounit;
1067
1068         P9_DPRINTK(P9_DEBUG_9P,
1069                         ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
1070                         ofid->fid, name, flags, mode, gid);
1071         clnt = ofid->clnt;
1072
1073         if (ofid->mode != -1)
1074                 return -EINVAL;
1075
1076         req = p9_client_rpc(clnt, P9_TLCREATE, "dsddd", ofid->fid, name, flags,
1077                         mode, gid);
1078         if (IS_ERR(req)) {
1079                 err = PTR_ERR(req);
1080                 goto error;
1081         }
1082
1083         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
1084         if (err) {
1085                 p9pdu_dump(1, req->rc);
1086                 goto free_and_error;
1087         }
1088
1089         P9_DPRINTK(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
1090                         qid->type,
1091                         (unsigned long long)qid->path,
1092                         qid->version, iounit);
1093
1094         ofid->mode = mode;
1095         ofid->iounit = iounit;
1096
1097 free_and_error:
1098         p9_free_req(clnt, req);
1099 error:
1100         return err;
1101 }
1102 EXPORT_SYMBOL(p9_client_create_dotl);
1103
1104 int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
1105                      char *extension)
1106 {
1107         int err;
1108         struct p9_client *clnt;
1109         struct p9_req_t *req;
1110         struct p9_qid qid;
1111         int iounit;
1112
1113         P9_DPRINTK(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
1114                                                 fid->fid, name, perm, mode);
1115         err = 0;
1116         clnt = fid->clnt;
1117
1118         if (fid->mode != -1)
1119                 return -EINVAL;
1120
1121         req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
1122                                 mode, extension);
1123         if (IS_ERR(req)) {
1124                 err = PTR_ERR(req);
1125                 goto error;
1126         }
1127
1128         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
1129         if (err) {
1130                 p9pdu_dump(1, req->rc);
1131                 goto free_and_error;
1132         }
1133
1134         P9_DPRINTK(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
1135                                 qid.type,
1136                                 (unsigned long long)qid.path,
1137                                 qid.version, iounit);
1138
1139         fid->mode = mode;
1140         fid->iounit = iounit;
1141
1142 free_and_error:
1143         p9_free_req(clnt, req);
1144 error:
1145         return err;
1146 }
1147 EXPORT_SYMBOL(p9_client_fcreate);
1148
1149 int p9_client_symlink(struct p9_fid *dfid, char *name, char *symtgt, gid_t gid,
1150                 struct p9_qid *qid)
1151 {
1152         int err = 0;
1153         struct p9_client *clnt;
1154         struct p9_req_t *req;
1155
1156         P9_DPRINTK(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
1157                         dfid->fid, name, symtgt);
1158         clnt = dfid->clnt;
1159
1160         req = p9_client_rpc(clnt, P9_TSYMLINK, "dssd", dfid->fid, name, symtgt,
1161                         gid);
1162         if (IS_ERR(req)) {
1163                 err = PTR_ERR(req);
1164                 goto error;
1165         }
1166
1167         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1168         if (err) {
1169                 p9pdu_dump(1, req->rc);
1170                 goto free_and_error;
1171         }
1172
1173         P9_DPRINTK(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
1174                         qid->type, (unsigned long long)qid->path, qid->version);
1175
1176 free_and_error:
1177         p9_free_req(clnt, req);
1178 error:
1179         return err;
1180 }
1181 EXPORT_SYMBOL(p9_client_symlink);
1182
1183 int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, char *newname)
1184 {
1185         struct p9_client *clnt;
1186         struct p9_req_t *req;
1187
1188         P9_DPRINTK(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
1189                         dfid->fid, oldfid->fid, newname);
1190         clnt = dfid->clnt;
1191         req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
1192                         newname);
1193         if (IS_ERR(req))
1194                 return PTR_ERR(req);
1195
1196         P9_DPRINTK(P9_DEBUG_9P, "<<< RLINK\n");
1197         p9_free_req(clnt, req);
1198         return 0;
1199 }
1200 EXPORT_SYMBOL(p9_client_link);
1201
1202 int p9_client_fsync(struct p9_fid *fid, int datasync)
1203 {
1204         int err;
1205         struct p9_client *clnt;
1206         struct p9_req_t *req;
1207
1208         P9_DPRINTK(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
1209                         fid->fid, datasync);
1210         err = 0;
1211         clnt = fid->clnt;
1212
1213         req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
1214         if (IS_ERR(req)) {
1215                 err = PTR_ERR(req);
1216                 goto error;
1217         }
1218
1219         P9_DPRINTK(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
1220
1221         p9_free_req(clnt, req);
1222
1223 error:
1224         return err;
1225 }
1226 EXPORT_SYMBOL(p9_client_fsync);
1227
1228 int p9_client_clunk(struct p9_fid *fid)
1229 {
1230         int err;
1231         struct p9_client *clnt;
1232         struct p9_req_t *req;
1233
1234         if (!fid) {
1235                 P9_EPRINTK(KERN_WARNING, "Trying to clunk with NULL fid\n");
1236                 dump_stack();
1237                 return 0;
1238         }
1239
1240         P9_DPRINTK(P9_DEBUG_9P, ">>> TCLUNK fid %d\n", fid->fid);
1241         err = 0;
1242         clnt = fid->clnt;
1243
1244         req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
1245         if (IS_ERR(req)) {
1246                 err = PTR_ERR(req);
1247                 goto error;
1248         }
1249
1250         P9_DPRINTK(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
1251
1252         p9_free_req(clnt, req);
1253 error:
1254         /*
1255          * Fid is not valid even after a failed clunk
1256          */
1257         p9_fid_destroy(fid);
1258         return err;
1259 }
1260 EXPORT_SYMBOL(p9_client_clunk);
1261
1262 int p9_client_remove(struct p9_fid *fid)
1263 {
1264         int err;
1265         struct p9_client *clnt;
1266         struct p9_req_t *req;
1267
1268         P9_DPRINTK(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
1269         err = 0;
1270         clnt = fid->clnt;
1271
1272         req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
1273         if (IS_ERR(req)) {
1274                 err = PTR_ERR(req);
1275                 goto error;
1276         }
1277
1278         P9_DPRINTK(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
1279
1280         p9_free_req(clnt, req);
1281 error:
1282         p9_fid_destroy(fid);
1283         return err;
1284 }
1285 EXPORT_SYMBOL(p9_client_remove);
1286
1287 int
1288 p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
1289                                                                 u32 count)
1290 {
1291         int err, rsize;
1292         struct p9_client *clnt;
1293         struct p9_req_t *req;
1294         char *dataptr;
1295
1296         P9_DPRINTK(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", fid->fid,
1297                                         (long long unsigned) offset, count);
1298         err = 0;
1299         clnt = fid->clnt;
1300
1301         rsize = fid->iounit;
1302         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1303                 rsize = clnt->msize - P9_IOHDRSZ;
1304
1305         if (count < rsize)
1306                 rsize = count;
1307
1308         /* Don't bother zerocopy for small IO (< 1024) */
1309         if (((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
1310                         P9_TRANS_PREF_PAYLOAD_SEP) && (rsize > 1024)) {
1311                 req = p9_client_rpc(clnt, P9_TREAD, "dqE", fid->fid, offset,
1312                                 rsize, data, udata);
1313         } else {
1314                 req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
1315                                 rsize);
1316         }
1317         if (IS_ERR(req)) {
1318                 err = PTR_ERR(req);
1319                 goto error;
1320         }
1321
1322         err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
1323         if (err) {
1324                 p9pdu_dump(1, req->rc);
1325                 goto free_and_error;
1326         }
1327
1328         P9_DPRINTK(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
1329
1330         if (!req->tc->pbuf_size) {
1331                 if (data) {
1332                         memmove(data, dataptr, count);
1333                 } else {
1334                         err = copy_to_user(udata, dataptr, count);
1335                         if (err) {
1336                                 err = -EFAULT;
1337                                 goto free_and_error;
1338                         }
1339                 }
1340         }
1341         p9_free_req(clnt, req);
1342         return count;
1343
1344 free_and_error:
1345         p9_free_req(clnt, req);
1346 error:
1347         return err;
1348 }
1349 EXPORT_SYMBOL(p9_client_read);
1350
1351 int
1352 p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
1353                                                         u64 offset, u32 count)
1354 {
1355         int err, rsize;
1356         struct p9_client *clnt;
1357         struct p9_req_t *req;
1358
1359         P9_DPRINTK(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
1360                                 fid->fid, (long long unsigned) offset, count);
1361         err = 0;
1362         clnt = fid->clnt;
1363
1364         rsize = fid->iounit;
1365         if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
1366                 rsize = clnt->msize - P9_IOHDRSZ;
1367
1368         if (count < rsize)
1369                 rsize = count;
1370
1371         /* Don't bother zerocopy form small IO (< 1024) */
1372         if (((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
1373                                 P9_TRANS_PREF_PAYLOAD_SEP) && (rsize > 1024)) {
1374                 req = p9_client_rpc(clnt, P9_TWRITE, "dqE", fid->fid, offset,
1375                                 rsize, data, udata);
1376         } else {
1377
1378                 if (data)
1379                         req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid,
1380                                         offset, rsize, data);
1381                 else
1382                         req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid,
1383                                         offset, rsize, udata);
1384         }
1385         if (IS_ERR(req)) {
1386                 err = PTR_ERR(req);
1387                 goto error;
1388         }
1389
1390         err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
1391         if (err) {
1392                 p9pdu_dump(1, req->rc);
1393                 goto free_and_error;
1394         }
1395
1396         P9_DPRINTK(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
1397
1398         p9_free_req(clnt, req);
1399         return count;
1400
1401 free_and_error:
1402         p9_free_req(clnt, req);
1403 error:
1404         return err;
1405 }
1406 EXPORT_SYMBOL(p9_client_write);
1407
1408 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
1409 {
1410         int err;
1411         struct p9_client *clnt;
1412         struct p9_wstat *ret = kmalloc(sizeof(struct p9_wstat), GFP_KERNEL);
1413         struct p9_req_t *req;
1414         u16 ignored;
1415
1416         P9_DPRINTK(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
1417
1418         if (!ret)
1419                 return ERR_PTR(-ENOMEM);
1420
1421         err = 0;
1422         clnt = fid->clnt;
1423
1424         req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
1425         if (IS_ERR(req)) {
1426                 err = PTR_ERR(req);
1427                 goto error;
1428         }
1429
1430         err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
1431         if (err) {
1432                 p9pdu_dump(1, req->rc);
1433                 p9_free_req(clnt, req);
1434                 goto error;
1435         }
1436
1437         P9_DPRINTK(P9_DEBUG_9P,
1438                 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1439                 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1440                 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1441                 "<<<    uid=%d gid=%d n_muid=%d\n",
1442                 ret->size, ret->type, ret->dev, ret->qid.type,
1443                 (unsigned long long)ret->qid.path, ret->qid.version, ret->mode,
1444                 ret->atime, ret->mtime, (unsigned long long)ret->length,
1445                 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
1446                 ret->n_uid, ret->n_gid, ret->n_muid);
1447
1448         p9_free_req(clnt, req);
1449         return ret;
1450
1451 error:
1452         kfree(ret);
1453         return ERR_PTR(err);
1454 }
1455 EXPORT_SYMBOL(p9_client_stat);
1456
1457 struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
1458                                                         u64 request_mask)
1459 {
1460         int err;
1461         struct p9_client *clnt;
1462         struct p9_stat_dotl *ret = kmalloc(sizeof(struct p9_stat_dotl),
1463                                                                 GFP_KERNEL);
1464         struct p9_req_t *req;
1465
1466         P9_DPRINTK(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
1467                                                         fid->fid, request_mask);
1468
1469         if (!ret)
1470                 return ERR_PTR(-ENOMEM);
1471
1472         err = 0;
1473         clnt = fid->clnt;
1474
1475         req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
1476         if (IS_ERR(req)) {
1477                 err = PTR_ERR(req);
1478                 goto error;
1479         }
1480
1481         err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
1482         if (err) {
1483                 p9pdu_dump(1, req->rc);
1484                 p9_free_req(clnt, req);
1485                 goto error;
1486         }
1487
1488         P9_DPRINTK(P9_DEBUG_9P,
1489                 "<<< RGETATTR st_result_mask=%lld\n"
1490                 "<<< qid=%x.%llx.%x\n"
1491                 "<<< st_mode=%8.8x st_nlink=%llu\n"
1492                 "<<< st_uid=%d st_gid=%d\n"
1493                 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
1494                 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
1495                 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
1496                 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
1497                 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
1498                 "<<< st_gen=%lld st_data_version=%lld",
1499                 ret->st_result_mask, ret->qid.type, ret->qid.path,
1500                 ret->qid.version, ret->st_mode, ret->st_nlink, ret->st_uid,
1501                 ret->st_gid, ret->st_rdev, ret->st_size, ret->st_blksize,
1502                 ret->st_blocks, ret->st_atime_sec, ret->st_atime_nsec,
1503                 ret->st_mtime_sec, ret->st_mtime_nsec, ret->st_ctime_sec,
1504                 ret->st_ctime_nsec, ret->st_btime_sec, ret->st_btime_nsec,
1505                 ret->st_gen, ret->st_data_version);
1506
1507         p9_free_req(clnt, req);
1508         return ret;
1509
1510 error:
1511         kfree(ret);
1512         return ERR_PTR(err);
1513 }
1514 EXPORT_SYMBOL(p9_client_getattr_dotl);
1515
1516 static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
1517 {
1518         int ret;
1519
1520         /* NOTE: size shouldn't include its own length */
1521         /* size[2] type[2] dev[4] qid[13] */
1522         /* mode[4] atime[4] mtime[4] length[8]*/
1523         /* name[s] uid[s] gid[s] muid[s] */
1524         ret = 2+4+13+4+4+4+8+2+2+2+2;
1525
1526         if (wst->name)
1527                 ret += strlen(wst->name);
1528         if (wst->uid)
1529                 ret += strlen(wst->uid);
1530         if (wst->gid)
1531                 ret += strlen(wst->gid);
1532         if (wst->muid)
1533                 ret += strlen(wst->muid);
1534
1535         if ((proto_version == p9_proto_2000u) ||
1536                 (proto_version == p9_proto_2000L)) {
1537                 ret += 2+4+4+4; /* extension[s] n_uid[4] n_gid[4] n_muid[4] */
1538                 if (wst->extension)
1539                         ret += strlen(wst->extension);
1540         }
1541
1542         return ret;
1543 }
1544
1545 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
1546 {
1547         int err;
1548         struct p9_req_t *req;
1549         struct p9_client *clnt;
1550
1551         err = 0;
1552         clnt = fid->clnt;
1553         wst->size = p9_client_statsize(wst, clnt->proto_version);
1554         P9_DPRINTK(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
1555         P9_DPRINTK(P9_DEBUG_9P,
1556                 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
1557                 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
1558                 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
1559                 "     uid=%d gid=%d n_muid=%d\n",
1560                 wst->size, wst->type, wst->dev, wst->qid.type,
1561                 (unsigned long long)wst->qid.path, wst->qid.version, wst->mode,
1562                 wst->atime, wst->mtime, (unsigned long long)wst->length,
1563                 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
1564                 wst->n_uid, wst->n_gid, wst->n_muid);
1565
1566         req = p9_client_rpc(clnt, P9_TWSTAT, "dwS", fid->fid, wst->size+2, wst);
1567         if (IS_ERR(req)) {
1568                 err = PTR_ERR(req);
1569                 goto error;
1570         }
1571
1572         P9_DPRINTK(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
1573
1574         p9_free_req(clnt, req);
1575 error:
1576         return err;
1577 }
1578 EXPORT_SYMBOL(p9_client_wstat);
1579
1580 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
1581 {
1582         int err;
1583         struct p9_req_t *req;
1584         struct p9_client *clnt;
1585
1586         err = 0;
1587         clnt = fid->clnt;
1588         P9_DPRINTK(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
1589         P9_DPRINTK(P9_DEBUG_9P,
1590                 "    valid=%x mode=%x uid=%d gid=%d size=%lld\n"
1591                 "    atime_sec=%lld atime_nsec=%lld\n"
1592                 "    mtime_sec=%lld mtime_nsec=%lld\n",
1593                 p9attr->valid, p9attr->mode, p9attr->uid, p9attr->gid,
1594                 p9attr->size, p9attr->atime_sec, p9attr->atime_nsec,
1595                 p9attr->mtime_sec, p9attr->mtime_nsec);
1596
1597         req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
1598
1599         if (IS_ERR(req)) {
1600                 err = PTR_ERR(req);
1601                 goto error;
1602         }
1603         P9_DPRINTK(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
1604         p9_free_req(clnt, req);
1605 error:
1606         return err;
1607 }
1608 EXPORT_SYMBOL(p9_client_setattr);
1609
1610 int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
1611 {
1612         int err;
1613         struct p9_req_t *req;
1614         struct p9_client *clnt;
1615
1616         err = 0;
1617         clnt = fid->clnt;
1618
1619         P9_DPRINTK(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
1620
1621         req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
1622         if (IS_ERR(req)) {
1623                 err = PTR_ERR(req);
1624                 goto error;
1625         }
1626
1627         err = p9pdu_readf(req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
1628                 &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
1629                 &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
1630         if (err) {
1631                 p9pdu_dump(1, req->rc);
1632                 p9_free_req(clnt, req);
1633                 goto error;
1634         }
1635
1636         P9_DPRINTK(P9_DEBUG_9P, "<<< RSTATFS fid %d type 0x%lx bsize %ld "
1637                 "blocks %llu bfree %llu bavail %llu files %llu ffree %llu "
1638                 "fsid %llu namelen %ld\n",
1639                 fid->fid, (long unsigned int)sb->type, (long int)sb->bsize,
1640                 sb->blocks, sb->bfree, sb->bavail, sb->files,  sb->ffree,
1641                 sb->fsid, (long int)sb->namelen);
1642
1643         p9_free_req(clnt, req);
1644 error:
1645         return err;
1646 }
1647 EXPORT_SYMBOL(p9_client_statfs);
1648
1649 int p9_client_rename(struct p9_fid *fid, struct p9_fid *newdirfid, char *name)
1650 {
1651         int err;
1652         struct p9_req_t *req;
1653         struct p9_client *clnt;
1654
1655         err = 0;
1656         clnt = fid->clnt;
1657
1658         P9_DPRINTK(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
1659                         fid->fid, newdirfid->fid, name);
1660
1661         req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
1662                         newdirfid->fid, name);
1663         if (IS_ERR(req)) {
1664                 err = PTR_ERR(req);
1665                 goto error;
1666         }
1667
1668         P9_DPRINTK(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
1669
1670         p9_free_req(clnt, req);
1671 error:
1672         return err;
1673 }
1674 EXPORT_SYMBOL(p9_client_rename);
1675
1676 /*
1677  * An xattrwalk without @attr_name gives the fid for the lisxattr namespace
1678  */
1679 struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
1680                                 const char *attr_name, u64 *attr_size)
1681 {
1682         int err;
1683         struct p9_req_t *req;
1684         struct p9_client *clnt;
1685         struct p9_fid *attr_fid;
1686
1687         err = 0;
1688         clnt = file_fid->clnt;
1689         attr_fid = p9_fid_create(clnt);
1690         if (IS_ERR(attr_fid)) {
1691                 err = PTR_ERR(attr_fid);
1692                 attr_fid = NULL;
1693                 goto error;
1694         }
1695         P9_DPRINTK(P9_DEBUG_9P,
1696                 ">>> TXATTRWALK file_fid %d, attr_fid %d name %s\n",
1697                 file_fid->fid, attr_fid->fid, attr_name);
1698
1699         req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
1700                         file_fid->fid, attr_fid->fid, attr_name);
1701         if (IS_ERR(req)) {
1702                 err = PTR_ERR(req);
1703                 goto error;
1704         }
1705         err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
1706         if (err) {
1707                 p9pdu_dump(1, req->rc);
1708                 p9_free_req(clnt, req);
1709                 goto clunk_fid;
1710         }
1711         p9_free_req(clnt, req);
1712         P9_DPRINTK(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
1713                 attr_fid->fid, *attr_size);
1714         return attr_fid;
1715 clunk_fid:
1716         p9_client_clunk(attr_fid);
1717         attr_fid = NULL;
1718 error:
1719         if (attr_fid && (attr_fid != file_fid))
1720                 p9_fid_destroy(attr_fid);
1721
1722         return ERR_PTR(err);
1723 }
1724 EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
1725
1726 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
1727                         u64 attr_size, int flags)
1728 {
1729         int err;
1730         struct p9_req_t *req;
1731         struct p9_client *clnt;
1732
1733         P9_DPRINTK(P9_DEBUG_9P,
1734                 ">>> TXATTRCREATE fid %d name  %s size %lld flag %d\n",
1735                 fid->fid, name, (long long)attr_size, flags);
1736         err = 0;
1737         clnt = fid->clnt;
1738         req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
1739                         fid->fid, name, attr_size, flags);
1740         if (IS_ERR(req)) {
1741                 err = PTR_ERR(req);
1742                 goto error;
1743         }
1744         P9_DPRINTK(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
1745         p9_free_req(clnt, req);
1746 error:
1747         return err;
1748 }
1749 EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
1750
1751 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
1752 {
1753         int err, rsize;
1754         struct p9_client *clnt;
1755         struct p9_req_t *req;
1756         char *dataptr;
1757
1758         P9_DPRINTK(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
1759                                 fid->fid, (long long unsigned) offset, count);
1760
1761         err = 0;
1762         clnt = fid->clnt;
1763
1764         rsize = fid->iounit;
1765         if (!rsize || rsize > clnt->msize-P9_READDIRHDRSZ)
1766                 rsize = clnt->msize - P9_READDIRHDRSZ;
1767
1768         if (count < rsize)
1769                 rsize = count;
1770
1771         if ((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
1772                         P9_TRANS_PREF_PAYLOAD_SEP) {
1773                 req = p9_client_rpc(clnt, P9_TREADDIR, "dqF", fid->fid,
1774                                 offset, rsize, data);
1775         } else {
1776                 req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
1777                                 offset, rsize);
1778         }
1779         if (IS_ERR(req)) {
1780                 err = PTR_ERR(req);
1781                 goto error;
1782         }
1783
1784         err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
1785         if (err) {
1786                 p9pdu_dump(1, req->rc);
1787                 goto free_and_error;
1788         }
1789
1790         P9_DPRINTK(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
1791
1792         if (!req->tc->pbuf_size && data)
1793                 memmove(data, dataptr, count);
1794
1795         p9_free_req(clnt, req);
1796         return count;
1797
1798 free_and_error:
1799         p9_free_req(clnt, req);
1800 error:
1801         return err;
1802 }
1803 EXPORT_SYMBOL(p9_client_readdir);
1804
1805 int p9_client_mknod_dotl(struct p9_fid *fid, char *name, int mode,
1806                         dev_t rdev, gid_t gid, struct p9_qid *qid)
1807 {
1808         int err;
1809         struct p9_client *clnt;
1810         struct p9_req_t *req;
1811
1812         err = 0;
1813         clnt = fid->clnt;
1814         P9_DPRINTK(P9_DEBUG_9P, ">>> TMKNOD fid %d name %s mode %d major %d "
1815                 "minor %d\n", fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
1816         req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddd", fid->fid, name, mode,
1817                 MAJOR(rdev), MINOR(rdev), gid);
1818         if (IS_ERR(req))
1819                 return PTR_ERR(req);
1820
1821         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1822         if (err) {
1823                 p9pdu_dump(1, req->rc);
1824                 goto error;
1825         }
1826         P9_DPRINTK(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
1827                                 (unsigned long long)qid->path, qid->version);
1828
1829 error:
1830         p9_free_req(clnt, req);
1831         return err;
1832
1833 }
1834 EXPORT_SYMBOL(p9_client_mknod_dotl);
1835
1836 int p9_client_mkdir_dotl(struct p9_fid *fid, char *name, int mode,
1837                                 gid_t gid, struct p9_qid *qid)
1838 {
1839         int err;
1840         struct p9_client *clnt;
1841         struct p9_req_t *req;
1842
1843         err = 0;
1844         clnt = fid->clnt;
1845         P9_DPRINTK(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
1846                  fid->fid, name, mode, gid);
1847         req = p9_client_rpc(clnt, P9_TMKDIR, "dsdd", fid->fid, name, mode,
1848                 gid);
1849         if (IS_ERR(req))
1850                 return PTR_ERR(req);
1851
1852         err = p9pdu_readf(req->rc, clnt->proto_version, "Q", qid);
1853         if (err) {
1854                 p9pdu_dump(1, req->rc);
1855                 goto error;
1856         }
1857         P9_DPRINTK(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
1858                                 (unsigned long long)qid->path, qid->version);
1859
1860 error:
1861         p9_free_req(clnt, req);
1862         return err;
1863
1864 }
1865 EXPORT_SYMBOL(p9_client_mkdir_dotl);
1866
1867 int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
1868 {
1869         int err;
1870         struct p9_client *clnt;
1871         struct p9_req_t *req;
1872
1873         err = 0;
1874         clnt = fid->clnt;
1875         P9_DPRINTK(P9_DEBUG_9P, ">>> TLOCK fid %d type %i flags %d "
1876                         "start %lld length %lld proc_id %d client_id %s\n",
1877                         fid->fid, flock->type, flock->flags, flock->start,
1878                         flock->length, flock->proc_id, flock->client_id);
1879
1880         req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
1881                                 flock->flags, flock->start, flock->length,
1882                                         flock->proc_id, flock->client_id);
1883
1884         if (IS_ERR(req))
1885                 return PTR_ERR(req);
1886
1887         err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
1888         if (err) {
1889                 p9pdu_dump(1, req->rc);
1890                 goto error;
1891         }
1892         P9_DPRINTK(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
1893 error:
1894         p9_free_req(clnt, req);
1895         return err;
1896
1897 }
1898 EXPORT_SYMBOL(p9_client_lock_dotl);
1899
1900 int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
1901 {
1902         int err;
1903         struct p9_client *clnt;
1904         struct p9_req_t *req;
1905
1906         err = 0;
1907         clnt = fid->clnt;
1908         P9_DPRINTK(P9_DEBUG_9P, ">>> TGETLOCK fid %d, type %i start %lld "
1909                 "length %lld proc_id %d client_id %s\n", fid->fid, glock->type,
1910                 glock->start, glock->length, glock->proc_id, glock->client_id);
1911
1912         req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,  glock->type,
1913                 glock->start, glock->length, glock->proc_id, glock->client_id);
1914
1915         if (IS_ERR(req))
1916                 return PTR_ERR(req);
1917
1918         err = p9pdu_readf(req->rc, clnt->proto_version, "bqqds", &glock->type,
1919                         &glock->start, &glock->length, &glock->proc_id,
1920                         &glock->client_id);
1921         if (err) {
1922                 p9pdu_dump(1, req->rc);
1923                 goto error;
1924         }
1925         P9_DPRINTK(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
1926                 "proc_id %d client_id %s\n", glock->type, glock->start,
1927                 glock->length, glock->proc_id, glock->client_id);
1928 error:
1929         p9_free_req(clnt, req);
1930         return err;
1931 }
1932 EXPORT_SYMBOL(p9_client_getlock_dotl);
1933
1934 int p9_client_readlink(struct p9_fid *fid, char **target)
1935 {
1936         int err;
1937         struct p9_client *clnt;
1938         struct p9_req_t *req;
1939
1940         err = 0;
1941         clnt = fid->clnt;
1942         P9_DPRINTK(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
1943
1944         req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
1945         if (IS_ERR(req))
1946                 return PTR_ERR(req);
1947
1948         err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
1949         if (err) {
1950                 p9pdu_dump(1, req->rc);
1951                 goto error;
1952         }
1953         P9_DPRINTK(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
1954 error:
1955         p9_free_req(clnt, req);
1956         return err;
1957 }
1958 EXPORT_SYMBOL(p9_client_readlink);