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