fs/9p/conv.c

   1 /*
   2  * linux/fs/9p/conv.c
   3  *
   4  * 9P protocol conversion functions
   5  *
   6  *  Copyright (C) 2004, 2005 by Latchesar Ionkov <lucho@ionkov.net>
   7  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
   8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2
  12  *  as published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to:
  21  *  Free Software Foundation
  22  *  51 Franklin Street, Fifth Floor
  23  *  Boston, MA  02111-1301  USA
  24  *
  25  */
  26
  27 #include <linux/config.h>
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/fs.h>
  31 #include <linux/idr.h>
  32 #include <asm/uaccess.h>
  33 #include "debug.h"
  34 #include "v9fs.h"
  35 #include "9p.h"
  36 #include "conv.h"
  37
  38 /*
  39  * Buffer to help with string parsing
  40  */
  41 struct cbuf {
  42         unsigned char *sp;
  43         unsigned char *p;
  44         unsigned char *ep;
  45 };
  46
  47 static inline void buf_init(struct cbuf *buf, void *data, int datalen)
  48 {
  49         buf->sp = buf->p = data;
  50         buf->ep = data + datalen;
  51 }
  52
  53 static inline int buf_check_overflow(struct cbuf *buf)
  54 {
  55         return buf->p > buf->ep;
  56 }
  57
  58 static int buf_check_size(struct cbuf *buf, int len)
  59 {
  60         if (buf->p + len > buf->ep) {
  61                 if (buf->p < buf->ep) {
  62                         eprintk(KERN_ERR, "buffer overflow: want %d has %d\n",
  63                                 len, (int)(buf->ep - buf->p));
  64                         dump_stack();
  65                         buf->p = buf->ep + 1;
  66                 }
  67
  68                 return 0;
  69         }
  70
  71         return 1;
  72 }
  73
  74 static void *buf_alloc(struct cbuf *buf, int len)
  75 {
  76         void *ret = NULL;
  77
  78         if (buf_check_size(buf, len)) {
  79                 ret = buf->p;
  80                 buf->p += len;
  81         }
  82
  83         return ret;
  84 }
  85
  86 static void buf_put_int8(struct cbuf *buf, u8 val)
  87 {
  88         if (buf_check_size(buf, 1)) {
  89                 buf->p[0] = val;
  90                 buf->p++;
  91         }
  92 }
  93
  94 static void buf_put_int16(struct cbuf *buf, u16 val)
  95 {
  96         if (buf_check_size(buf, 2)) {
  97                 *(__le16 *) buf->p = cpu_to_le16(val);
  98                 buf->p += 2;
  99         }
 100 }
 101
 102 static void buf_put_int32(struct cbuf *buf, u32 val)
 103 {
 104         if (buf_check_size(buf, 4)) {
 105                 *(__le32 *)buf->p = cpu_to_le32(val);
 106                 buf->p += 4;
 107         }
 108 }
 109
 110 static void buf_put_int64(struct cbuf *buf, u64 val)
 111 {
 112         if (buf_check_size(buf, 8)) {
 113                 *(__le64 *)buf->p = cpu_to_le64(val);
 114                 buf->p += 8;
 115         }
 116 }
 117
 118 static char *buf_put_stringn(struct cbuf *buf, const char *s, u16 slen)
 119 {
 120         char *ret;
 121
 122         ret = NULL;
 123         if (buf_check_size(buf, slen + 2)) {
 124                 buf_put_int16(buf, slen);
 125                 ret = buf->p;
 126                 memcpy(buf->p, s, slen);
 127                 buf->p += slen;
 128         }
 129
 130         return ret;
 131 }
 132
 133 static inline void buf_put_string(struct cbuf *buf, const char *s)
 134 {
 135         buf_put_stringn(buf, s, strlen(s));
 136 }
 137
 138 static u8 buf_get_int8(struct cbuf *buf)
 139 {
 140         u8 ret = 0;
 141
 142         if (buf_check_size(buf, 1)) {
 143                 ret = buf->p[0];
 144                 buf->p++;
 145         }
 146
 147         return ret;
 148 }
 149
 150 static u16 buf_get_int16(struct cbuf *buf)
 151 {
 152         u16 ret = 0;
 153
 154         if (buf_check_size(buf, 2)) {
 155                 ret = le16_to_cpu(*(__le16 *)buf->p);
 156                 buf->p += 2;
 157         }
 158
 159         return ret;
 160 }
 161
 162 static u32 buf_get_int32(struct cbuf *buf)
 163 {
 164         u32 ret = 0;
 165
 166         if (buf_check_size(buf, 4)) {
 167                 ret = le32_to_cpu(*(__le32 *)buf->p);
 168                 buf->p += 4;
 169         }
 170
 171         return ret;
 172 }
 173
 174 static u64 buf_get_int64(struct cbuf *buf)
 175 {
 176         u64 ret = 0;
 177
 178         if (buf_check_size(buf, 8)) {
 179                 ret = le64_to_cpu(*(__le64 *)buf->p);
 180                 buf->p += 8;
 181         }
 182
 183         return ret;
 184 }
 185
 186 static void buf_get_str(struct cbuf *buf, struct v9fs_str *vstr)
 187 {
 188         vstr->len = buf_get_int16(buf);
 189         if (!buf_check_overflow(buf) && buf_check_size(buf, vstr->len)) {
 190                 vstr->str = buf->p;
 191                 buf->p += vstr->len;
 192         } else {
 193                 vstr->len = 0;
 194                 vstr->str = NULL;
 195         }
 196 }
 197
 198 static void buf_get_qid(struct cbuf *bufp, struct v9fs_qid *qid)
 199 {
 200         qid->type = buf_get_int8(bufp);
 201         qid->version = buf_get_int32(bufp);
 202         qid->path = buf_get_int64(bufp);
 203 }
 204
 205 /**
 206  * v9fs_size_wstat - calculate the size of a variable length stat struct
 207  * @stat: metadata (stat) structure
 208  * @extended: non-zero if 9P2000.u
 209  *
 210  */
 211
 212 static int v9fs_size_wstat(struct v9fs_wstat *wstat, int extended)
 213 {
 214         int size = 0;
 215
 216         if (wstat == NULL) {
 217                 eprintk(KERN_ERR, "v9fs_size_stat: got a NULL stat pointer\n");
 218                 return 0;
 219         }
 220
 221         size =                  /* 2 + *//* size[2] */
 222             2 +                 /* type[2] */
 223             4 +                 /* dev[4] */
 224             1 +                 /* qid.type[1] */
 225             4 +                 /* qid.vers[4] */
 226             8 +                 /* qid.path[8] */
 227             4 +                 /* mode[4] */
 228             4 +                 /* atime[4] */
 229             4 +                 /* mtime[4] */
 230             8 +                 /* length[8] */
 231             8;                  /* minimum sum of string lengths */
 232
 233         if (wstat->name)
 234                 size += strlen(wstat->name);
 235         if (wstat->uid)
 236                 size += strlen(wstat->uid);
 237         if (wstat->gid)
 238                 size += strlen(wstat->gid);
 239         if (wstat->muid)
 240                 size += strlen(wstat->muid);
 241
 242         if (extended) {
 243                 size += 4 +     /* n_uid[4] */
 244                     4 +         /* n_gid[4] */
 245                     4 +         /* n_muid[4] */
 246                     2;          /* string length of extension[4] */
 247                 if (wstat->extension)
 248                         size += strlen(wstat->extension);
 249         }
 250
 251         return size;
 252 }
 253
 254 /**
 255  * buf_get_stat - safely decode a recieved metadata (stat) structure
 256  * @bufp: buffer to deserialize
 257  * @stat: metadata (stat) structure
 258  * @extended: non-zero if 9P2000.u
 259  *
 260  */
 261
 262 static void
 263 buf_get_stat(struct cbuf *bufp, struct v9fs_stat *stat, int extended)
 264 {
 265         stat->size = buf_get_int16(bufp);
 266         stat->type = buf_get_int16(bufp);
 267         stat->dev = buf_get_int32(bufp);
 268         stat->qid.type = buf_get_int8(bufp);
 269         stat->qid.version = buf_get_int32(bufp);
 270         stat->qid.path = buf_get_int64(bufp);
 271         stat->mode = buf_get_int32(bufp);
 272         stat->atime = buf_get_int32(bufp);
 273         stat->mtime = buf_get_int32(bufp);
 274         stat->length = buf_get_int64(bufp);
 275         buf_get_str(bufp, &stat->name);
 276         buf_get_str(bufp, &stat->uid);
 277         buf_get_str(bufp, &stat->gid);
 278         buf_get_str(bufp, &stat->muid);
 279
 280         if (extended) {
 281                 buf_get_str(bufp, &stat->extension);
 282                 stat->n_uid = buf_get_int32(bufp);
 283                 stat->n_gid = buf_get_int32(bufp);
 284                 stat->n_muid = buf_get_int32(bufp);
 285         }
 286 }
 287
 288 /**
 289  * v9fs_deserialize_stat - decode a received metadata structure
 290  * @buf: buffer to deserialize
 291  * @buflen: length of received buffer
 292  * @stat: metadata structure to decode into
 293  * @extended: non-zero if 9P2000.u
 294  *
 295  * Note: stat will point to the buf region.
 296  */
 297
 298 int
 299 v9fs_deserialize_stat(void *buf, u32 buflen, struct v9fs_stat *stat,
 300                 int extended)
 301 {
 302         struct cbuf buffer;
 303         struct cbuf *bufp = &buffer;
 304         unsigned char *p;
 305
 306         buf_init(bufp, buf, buflen);
 307         p = bufp->p;
 308         buf_get_stat(bufp, stat, extended);
 309
 310         if (buf_check_overflow(bufp))
 311                 return 0;
 312         else
 313                 return bufp->p - p;
 314 }
 315
 316 /**
 317  * deserialize_fcall - unmarshal a response
 318  * @buf: recieved buffer
 319  * @buflen: length of received buffer
 320  * @rcall: fcall structure to populate
 321  * @rcalllen: length of fcall structure to populate
 322  * @extended: non-zero if 9P2000.u
 323  *
 324  */
 325
 326 int
 327 v9fs_deserialize_fcall(void *buf, u32 buflen, struct v9fs_fcall *rcall,
 328                        int extended)
 329 {
 330
 331         struct cbuf buffer;
 332         struct cbuf *bufp = &buffer;
 333         int i = 0;
 334
 335         buf_init(bufp, buf, buflen);
 336
 337         rcall->size = buf_get_int32(bufp);
 338         rcall->id = buf_get_int8(bufp);
 339         rcall->tag = buf_get_int16(bufp);
 340
 341         dprintk(DEBUG_CONV, "size %d id %d tag %d\n", rcall->size, rcall->id,
 342                 rcall->tag);
 343
 344         switch (rcall->id) {
 345         default:
 346                 eprintk(KERN_ERR, "unknown message type: %d\n", rcall->id);
 347                 return -EPROTO;
 348         case RVERSION:
 349                 rcall->params.rversion.msize = buf_get_int32(bufp);
 350                 buf_get_str(bufp, &rcall->params.rversion.version);
 351                 break;
 352         case RFLUSH:
 353                 break;
 354         case RATTACH:
 355                 rcall->params.rattach.qid.type = buf_get_int8(bufp);
 356                 rcall->params.rattach.qid.version = buf_get_int32(bufp);
 357                 rcall->params.rattach.qid.path = buf_get_int64(bufp);
 358                 break;
 359         case RWALK:
 360                 rcall->params.rwalk.nwqid = buf_get_int16(bufp);
 361                 if (rcall->params.rwalk.nwqid > V9FS_MAXWELEM) {
 362                         eprintk(KERN_ERR, "Rwalk with more than %d qids: %d\n",
 363                                 V9FS_MAXWELEM, rcall->params.rwalk.nwqid);
 364                         return -EPROTO;
 365                 }
 366
 367                 for (i = 0; i < rcall->params.rwalk.nwqid; i++)
 368                         buf_get_qid(bufp, &rcall->params.rwalk.wqids[i]);
 369                 break;
 370         case ROPEN:
 371                 buf_get_qid(bufp, &rcall->params.ropen.qid);
 372                 rcall->params.ropen.iounit = buf_get_int32(bufp);
 373                 break;
 374         case RCREATE:
 375                 buf_get_qid(bufp, &rcall->params.rcreate.qid);
 376                 rcall->params.rcreate.iounit = buf_get_int32(bufp);
 377                 break;
 378         case RREAD:
 379                 rcall->params.rread.count = buf_get_int32(bufp);
 380                 rcall->params.rread.data = bufp->p;
 381                 buf_check_size(bufp, rcall->params.rread.count);
 382                 break;
 383         case RWRITE:
 384                 rcall->params.rwrite.count = buf_get_int32(bufp);
 385                 break;
 386         case RCLUNK:
 387                 break;
 388         case RREMOVE:
 389                 break;
 390         case RSTAT:
 391                 buf_get_int16(bufp);
 392                 buf_get_stat(bufp, &rcall->params.rstat.stat, extended);
 393                 break;
 394         case RWSTAT:
 395                 break;
 396         case RERROR:
 397                 buf_get_str(bufp, &rcall->params.rerror.error);
 398                 if (extended)
 399                         rcall->params.rerror.errno = buf_get_int16(bufp);
 400                 break;
 401         }
 402
 403         if (buf_check_overflow(bufp)) {
 404                 dprintk(DEBUG_ERROR, "buffer overflow\n");
 405                 return -EIO;
 406         }
 407
 408         return bufp->p - bufp->sp;
 409 }
 410
 411 static inline void v9fs_put_int8(struct cbuf *bufp, u8 val, u8 * p)
 412 {
 413         *p = val;
 414         buf_put_int8(bufp, val);
 415 }
 416
 417 static inline void v9fs_put_int16(struct cbuf *bufp, u16 val, u16 * p)
 418 {
 419         *p = val;
 420         buf_put_int16(bufp, val);
 421 }
 422
 423 static inline void v9fs_put_int32(struct cbuf *bufp, u32 val, u32 * p)
 424 {
 425         *p = val;
 426         buf_put_int32(bufp, val);
 427 }
 428
 429 static inline void v9fs_put_int64(struct cbuf *bufp, u64 val, u64 * p)
 430 {
 431         *p = val;
 432         buf_put_int64(bufp, val);
 433 }
 434
 435 static void
 436 v9fs_put_str(struct cbuf *bufp, char *data, struct v9fs_str *str)
 437 {
 438         int len;
 439         char *s;
 440
 441         if (data)
 442                 len = strlen(data);
 443         else
 444                 len = 0;
 445
 446         s = buf_put_stringn(bufp, data, len);
 447         if (str) {
 448                 str->len = len;
 449                 str->str = s;
 450         }
 451 }
 452
 453 static int
 454 v9fs_put_user_data(struct cbuf *bufp, const char __user * data, int count,
 455                    unsigned char **pdata)
 456 {
 457         *pdata = buf_alloc(bufp, count);
 458         return copy_from_user(*pdata, data, count);
 459 }
 460
 461 static void
 462 v9fs_put_wstat(struct cbuf *bufp, struct v9fs_wstat *wstat,
 463                struct v9fs_stat *stat, int statsz, int extended)
 464 {
 465         v9fs_put_int16(bufp, statsz, &stat->size);
 466         v9fs_put_int16(bufp, wstat->type, &stat->type);
 467         v9fs_put_int32(bufp, wstat->dev, &stat->dev);
 468         v9fs_put_int8(bufp, wstat->qid.type, &stat->qid.type);
 469         v9fs_put_int32(bufp, wstat->qid.version, &stat->qid.version);
 470         v9fs_put_int64(bufp, wstat->qid.path, &stat->qid.path);
 471         v9fs_put_int32(bufp, wstat->mode, &stat->mode);
 472         v9fs_put_int32(bufp, wstat->atime, &stat->atime);
 473         v9fs_put_int32(bufp, wstat->mtime, &stat->mtime);
 474         v9fs_put_int64(bufp, wstat->length, &stat->length);
 475
 476         v9fs_put_str(bufp, wstat->name, &stat->name);
 477         v9fs_put_str(bufp, wstat->uid, &stat->uid);
 478         v9fs_put_str(bufp, wstat->gid, &stat->gid);
 479         v9fs_put_str(bufp, wstat->muid, &stat->muid);
 480
 481         if (extended) {
 482                 v9fs_put_str(bufp, wstat->extension, &stat->extension);
 483                 v9fs_put_int32(bufp, wstat->n_uid, &stat->n_uid);
 484                 v9fs_put_int32(bufp, wstat->n_gid, &stat->n_gid);
 485                 v9fs_put_int32(bufp, wstat->n_muid, &stat->n_muid);
 486         }
 487 }
 488
 489 static struct v9fs_fcall *
 490 v9fs_create_common(struct cbuf *bufp, u32 size, u8 id)
 491 {
 492         struct v9fs_fcall *fc;
 493
 494         size += 4 + 1 + 2;      /* size[4] id[1] tag[2] */
 495         fc = kmalloc(sizeof(struct v9fs_fcall) + size, GFP_KERNEL);
 496         if (!fc)
 497                 return ERR_PTR(-ENOMEM);
 498
 499         fc->sdata = (char *)fc + sizeof(*fc);
 500
 501         buf_init(bufp, (char *)fc->sdata, size);
 502         v9fs_put_int32(bufp, size, &fc->size);
 503         v9fs_put_int8(bufp, id, &fc->id);
 504         v9fs_put_int16(bufp, V9FS_NOTAG, &fc->tag);
 505
 506         return fc;
 507 }
 508
 509 void v9fs_set_tag(struct v9fs_fcall *fc, u16 tag)
 510 {
 511         fc->tag = tag;
 512         *(__le16 *) (fc->sdata + 5) = cpu_to_le16(tag);
 513 }
 514
 515 struct v9fs_fcall *v9fs_create_tversion(u32 msize, char *version)
 516 {
 517         int size;
 518         struct v9fs_fcall *fc;
 519         struct cbuf buffer;
 520         struct cbuf *bufp = &buffer;
 521
 522         size = 4 + 2 + strlen(version); /* msize[4] version[s] */
 523         fc = v9fs_create_common(bufp, size, TVERSION);
 524         if (IS_ERR(fc))
 525                 goto error;
 526
 527         v9fs_put_int32(bufp, msize, &fc->params.tversion.msize);
 528         v9fs_put_str(bufp, version, &fc->params.tversion.version);
 529
 530         if (buf_check_overflow(bufp)) {
 531                 kfree(fc);
 532                 fc = ERR_PTR(-ENOMEM);
 533         }
 534       error:
 535         return fc;
 536 }
 537
 538 #if 0
 539 struct v9fs_fcall *v9fs_create_tauth(u32 afid, char *uname, char *aname)
 540 {
 541         int size;
 542         struct v9fs_fcall *fc;
 543         struct cbuf buffer;
 544         struct cbuf *bufp = &buffer;
 545
 546         size = 4 + 2 + strlen(uname) + 2 + strlen(aname);       /* afid[4] uname[s] aname[s] */
 547         fc = v9fs_create_common(bufp, size, TAUTH);
 548         if (IS_ERR(fc))
 549                 goto error;
 550
 551         v9fs_put_int32(bufp, afid, &fc->params.tauth.afid);
 552         v9fs_put_str(bufp, uname, &fc->params.tauth.uname);
 553         v9fs_put_str(bufp, aname, &fc->params.tauth.aname);
 554
 555         if (buf_check_overflow(bufp)) {
 556                 kfree(fc);
 557                 fc = ERR_PTR(-ENOMEM);
 558         }
 559       error:
 560         return fc;
 561 }
 562 #endif  /*  0  */
 563
 564 struct v9fs_fcall *
 565 v9fs_create_tattach(u32 fid, u32 afid, char *uname, char *aname)
 566 {
 567         int size;
 568         struct v9fs_fcall *fc;
 569         struct cbuf buffer;
 570         struct cbuf *bufp = &buffer;
 571
 572         size = 4 + 4 + 2 + strlen(uname) + 2 + strlen(aname);   /* fid[4] afid[4] uname[s] aname[s] */
 573         fc = v9fs_create_common(bufp, size, TATTACH);
 574         if (IS_ERR(fc))
 575                 goto error;
 576
 577         v9fs_put_int32(bufp, fid, &fc->params.tattach.fid);
 578         v9fs_put_int32(bufp, afid, &fc->params.tattach.afid);
 579         v9fs_put_str(bufp, uname, &fc->params.tattach.uname);
 580         v9fs_put_str(bufp, aname, &fc->params.tattach.aname);
 581
 582       error:
 583         return fc;
 584 }
 585
 586 struct v9fs_fcall *v9fs_create_tflush(u16 oldtag)
 587 {
 588         int size;
 589         struct v9fs_fcall *fc;
 590         struct cbuf buffer;
 591         struct cbuf *bufp = &buffer;
 592
 593         size = 2;               /* oldtag[2] */
 594         fc = v9fs_create_common(bufp, size, TFLUSH);
 595         if (IS_ERR(fc))
 596                 goto error;
 597
 598         v9fs_put_int16(bufp, oldtag, &fc->params.tflush.oldtag);
 599
 600         if (buf_check_overflow(bufp)) {
 601                 kfree(fc);
 602                 fc = ERR_PTR(-ENOMEM);
 603         }
 604       error:
 605         return fc;
 606 }
 607
 608 struct v9fs_fcall *v9fs_create_twalk(u32 fid, u32 newfid, u16 nwname,
 609                                      char **wnames)
 610 {
 611         int i, size;
 612         struct v9fs_fcall *fc;
 613         struct cbuf buffer;
 614         struct cbuf *bufp = &buffer;
 615
 616         if (nwname > V9FS_MAXWELEM) {
 617                 dprintk(DEBUG_ERROR, "nwname > %d\n", V9FS_MAXWELEM);
 618                 return NULL;
 619         }
 620
 621         size = 4 + 4 + 2;       /* fid[4] newfid[4] nwname[2] ... */
 622         for (i = 0; i < nwname; i++) {
 623                 size += 2 + strlen(wnames[i]);  /* wname[s] */
 624         }
 625
 626         fc = v9fs_create_common(bufp, size, TWALK);
 627         if (IS_ERR(fc))
 628                 goto error;
 629
 630         v9fs_put_int32(bufp, fid, &fc->params.twalk.fid);
 631         v9fs_put_int32(bufp, newfid, &fc->params.twalk.newfid);
 632         v9fs_put_int16(bufp, nwname, &fc->params.twalk.nwname);
 633         for (i = 0; i < nwname; i++) {
 634                 v9fs_put_str(bufp, wnames[i], &fc->params.twalk.wnames[i]);
 635         }
 636
 637         if (buf_check_overflow(bufp)) {
 638                 kfree(fc);
 639                 fc = ERR_PTR(-ENOMEM);
 640         }
 641       error:
 642         return fc;
 643 }
 644
 645 struct v9fs_fcall *v9fs_create_topen(u32 fid, u8 mode)
 646 {
 647         int size;
 648         struct v9fs_fcall *fc;
 649         struct cbuf buffer;
 650         struct cbuf *bufp = &buffer;
 651
 652         size = 4 + 1;           /* fid[4] mode[1] */
 653         fc = v9fs_create_common(bufp, size, TOPEN);
 654         if (IS_ERR(fc))
 655                 goto error;
 656
 657         v9fs_put_int32(bufp, fid, &fc->params.topen.fid);
 658         v9fs_put_int8(bufp, mode, &fc->params.topen.mode);
 659
 660         if (buf_check_overflow(bufp)) {
 661                 kfree(fc);
 662                 fc = ERR_PTR(-ENOMEM);
 663         }
 664       error:
 665         return fc;
 666 }
 667
 668 struct v9fs_fcall *v9fs_create_tcreate(u32 fid, char *name, u32 perm, u8 mode,
 669         char *extension, int extended)
 670 {
 671         int size;
 672         struct v9fs_fcall *fc;
 673         struct cbuf buffer;
 674         struct cbuf *bufp = &buffer;
 675
 676         size = 4 + 2 + strlen(name) + 4 + 1;    /* fid[4] name[s] perm[4] mode[1] */
 677         if (extended && extension!=NULL)
 678                 size += 2 + strlen(extension);  /* extension[s] */
 679
 680         fc = v9fs_create_common(bufp, size, TCREATE);
 681         if (IS_ERR(fc))
 682                 goto error;
 683
 684         v9fs_put_int32(bufp, fid, &fc->params.tcreate.fid);
 685         v9fs_put_str(bufp, name, &fc->params.tcreate.name);
 686         v9fs_put_int32(bufp, perm, &fc->params.tcreate.perm);
 687         v9fs_put_int8(bufp, mode, &fc->params.tcreate.mode);
 688         if (extended)
 689                 v9fs_put_str(bufp, extension, &fc->params.tcreate.extension);
 690
 691         if (buf_check_overflow(bufp)) {
 692                 kfree(fc);
 693                 fc = ERR_PTR(-ENOMEM);
 694         }
 695       error:
 696         return fc;
 697 }
 698
 699 struct v9fs_fcall *v9fs_create_tread(u32 fid, u64 offset, u32 count)
 700 {
 701         int size;
 702         struct v9fs_fcall *fc;
 703         struct cbuf buffer;
 704         struct cbuf *bufp = &buffer;
 705
 706         size = 4 + 8 + 4;       /* fid[4] offset[8] count[4] */
 707         fc = v9fs_create_common(bufp, size, TREAD);
 708         if (IS_ERR(fc))
 709                 goto error;
 710
 711         v9fs_put_int32(bufp, fid, &fc->params.tread.fid);
 712         v9fs_put_int64(bufp, offset, &fc->params.tread.offset);
 713         v9fs_put_int32(bufp, count, &fc->params.tread.count);
 714
 715         if (buf_check_overflow(bufp)) {
 716                 kfree(fc);
 717                 fc = ERR_PTR(-ENOMEM);
 718         }
 719       error:
 720         return fc;
 721 }
 722
 723 struct v9fs_fcall *v9fs_create_twrite(u32 fid, u64 offset, u32 count,
 724                                       const char __user * data)
 725 {
 726         int size, err;
 727         struct v9fs_fcall *fc;
 728         struct cbuf buffer;
 729         struct cbuf *bufp = &buffer;
 730
 731         size = 4 + 8 + 4 + count;       /* fid[4] offset[8] count[4] data[count] */
 732         fc = v9fs_create_common(bufp, size, TWRITE);
 733         if (IS_ERR(fc))
 734                 goto error;
 735
 736         v9fs_put_int32(bufp, fid, &fc->params.twrite.fid);
 737         v9fs_put_int64(bufp, offset, &fc->params.twrite.offset);
 738         v9fs_put_int32(bufp, count, &fc->params.twrite.count);
 739         err = v9fs_put_user_data(bufp, data, count, &fc->params.twrite.data);
 740         if (err) {
 741                 kfree(fc);
 742                 fc = ERR_PTR(err);
 743         }
 744
 745         if (buf_check_overflow(bufp)) {
 746                 kfree(fc);
 747                 fc = ERR_PTR(-ENOMEM);
 748         }
 749       error:
 750         return fc;
 751 }
 752
 753 struct v9fs_fcall *v9fs_create_tclunk(u32 fid)
 754 {
 755         int size;
 756         struct v9fs_fcall *fc;
 757         struct cbuf buffer;
 758         struct cbuf *bufp = &buffer;
 759
 760         size = 4;               /* fid[4] */
 761         fc = v9fs_create_common(bufp, size, TCLUNK);
 762         if (IS_ERR(fc))
 763                 goto error;
 764
 765         v9fs_put_int32(bufp, fid, &fc->params.tclunk.fid);
 766
 767         if (buf_check_overflow(bufp)) {
 768                 kfree(fc);
 769                 fc = ERR_PTR(-ENOMEM);
 770         }
 771       error:
 772         return fc;
 773 }
 774
 775 struct v9fs_fcall *v9fs_create_tremove(u32 fid)
 776 {
 777         int size;
 778         struct v9fs_fcall *fc;
 779         struct cbuf buffer;
 780         struct cbuf *bufp = &buffer;
 781
 782         size = 4;               /* fid[4] */
 783         fc = v9fs_create_common(bufp, size, TREMOVE);
 784         if (IS_ERR(fc))
 785                 goto error;
 786
 787         v9fs_put_int32(bufp, fid, &fc->params.tremove.fid);
 788
 789         if (buf_check_overflow(bufp)) {
 790                 kfree(fc);
 791                 fc = ERR_PTR(-ENOMEM);
 792         }
 793       error:
 794         return fc;
 795 }
 796
 797 struct v9fs_fcall *v9fs_create_tstat(u32 fid)
 798 {
 799         int size;
 800         struct v9fs_fcall *fc;
 801         struct cbuf buffer;
 802         struct cbuf *bufp = &buffer;
 803
 804         size = 4;               /* fid[4] */
 805         fc = v9fs_create_common(bufp, size, TSTAT);
 806         if (IS_ERR(fc))
 807                 goto error;
 808
 809         v9fs_put_int32(bufp, fid, &fc->params.tstat.fid);
 810
 811         if (buf_check_overflow(bufp)) {
 812                 kfree(fc);
 813                 fc = ERR_PTR(-ENOMEM);
 814         }
 815       error:
 816         return fc;
 817 }
 818
 819 struct v9fs_fcall *v9fs_create_twstat(u32 fid, struct v9fs_wstat *wstat,
 820                                       int extended)
 821 {
 822         int size, statsz;
 823         struct v9fs_fcall *fc;
 824         struct cbuf buffer;
 825         struct cbuf *bufp = &buffer;
 826
 827         statsz = v9fs_size_wstat(wstat, extended);
 828         size = 4 + 2 + 2 + statsz;      /* fid[4] stat[n] */
 829         fc = v9fs_create_common(bufp, size, TWSTAT);
 830         if (IS_ERR(fc))
 831                 goto error;
 832
 833         v9fs_put_int32(bufp, fid, &fc->params.twstat.fid);
 834         buf_put_int16(bufp, statsz + 2);
 835         v9fs_put_wstat(bufp, wstat, &fc->params.twstat.stat, statsz, extended);
 836
 837         if (buf_check_overflow(bufp)) {
 838                 kfree(fc);
 839                 fc = ERR_PTR(-ENOMEM);
 840         }
 841       error:
 842         return fc;
 843 }