fs/coda/upcall.c

   1 /*
   2  * Mostly platform independent upcall operations to Venus:
   3  *  -- upcalls
   4  *  -- upcall routines
   5  *
   6  * Linux 2.0 version
   7  * Copyright (C) 1996 Peter J. Braam <braam@maths.ox.ac.uk>,
   8  * Michael Callahan <callahan@maths.ox.ac.uk>
   9  *
  10  * Redone for Linux 2.1
  11  * Copyright (C) 1997 Carnegie Mellon University
  12  *
  13  * Carnegie Mellon University encourages users of this code to contribute
  14  * improvements to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>.
  15  */
  16
  17 #include <linux/signal.h>
  18 #include <linux/sched/signal.h>
  19 #include <linux/types.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/time.h>
  23 #include <linux/fs.h>
  24 #include <linux/file.h>
  25 #include <linux/stat.h>
  26 #include <linux/errno.h>
  27 #include <linux/string.h>
  28 #include <linux/slab.h>
  29 #include <linux/mutex.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/vmalloc.h>
  32 #include <linux/vfs.h>
  33
  34 #include <linux/coda.h>
  35 #include <linux/coda_psdev.h>
  36 #include "coda_linux.h"
  37 #include "coda_cache.h"
  38
  39 #include "coda_int.h"
  40
  41 static int coda_upcall(struct venus_comm *vc, int inSize, int *outSize,
  42                        union inputArgs *buffer);
  43
  44 static void *alloc_upcall(int opcode, int size)
  45 {
  46         union inputArgs *inp;
  47
  48         CODA_ALLOC(inp, union inputArgs *, size);
  49         if (!inp)
  50                 return ERR_PTR(-ENOMEM);
  51
  52         inp->ih.opcode = opcode;
  53         inp->ih.pid = task_pid_nr_ns(current, &init_pid_ns);
  54         inp->ih.pgid = task_pgrp_nr_ns(current, &init_pid_ns);
  55         inp->ih.uid = from_kuid(&init_user_ns, current_fsuid());
  56
  57         return (void*)inp;
  58 }
  59
  60 #define UPARG(op)\
  61 do {\
  62         inp = (union inputArgs *)alloc_upcall(op, insize); \
  63         if (IS_ERR(inp)) { return PTR_ERR(inp); }\
  64         outp = (union outputArgs *)(inp); \
  65         outsize = insize; \
  66 } while (0)
  67
  68 #define INSIZE(tag) sizeof(struct coda_ ## tag ## _in)
  69 #define OUTSIZE(tag) sizeof(struct coda_ ## tag ## _out)
  70 #define SIZE(tag)  max_t(unsigned int, INSIZE(tag), OUTSIZE(tag))
  71
  72
  73 /* the upcalls */
  74 int venus_rootfid(struct super_block *sb, struct CodaFid *fidp)
  75 {
  76         union inputArgs *inp;
  77         union outputArgs *outp;
  78         int insize, outsize, error;
  79
  80         insize = SIZE(root);
  81         UPARG(CODA_ROOT);
  82
  83         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
  84         if (!error)
  85                 *fidp = outp->coda_root.VFid;
  86
  87         CODA_FREE(inp, insize);
  88         return error;
  89 }
  90
  91 int venus_getattr(struct super_block *sb, struct CodaFid *fid,
  92                      struct coda_vattr *attr)
  93 {
  94         union inputArgs *inp;
  95         union outputArgs *outp;
  96         int insize, outsize, error;
  97
  98         insize = SIZE(getattr);
  99         UPARG(CODA_GETATTR);
 100         inp->coda_getattr.VFid = *fid;
 101
 102         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 103         if (!error)
 104                 *attr = outp->coda_getattr.attr;
 105
 106         CODA_FREE(inp, insize);
 107         return error;
 108 }
 109
 110 int venus_setattr(struct super_block *sb, struct CodaFid *fid,
 111                   struct coda_vattr *vattr)
 112 {
 113         union inputArgs *inp;
 114         union outputArgs *outp;
 115         int insize, outsize, error;
 116
 117         insize = SIZE(setattr);
 118         UPARG(CODA_SETATTR);
 119
 120         inp->coda_setattr.VFid = *fid;
 121         inp->coda_setattr.attr = *vattr;
 122
 123         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 124
 125         CODA_FREE(inp, insize);
 126         return error;
 127 }
 128
 129 int venus_lookup(struct super_block *sb, struct CodaFid *fid,
 130                     const char *name, int length, int * type,
 131                     struct CodaFid *resfid)
 132 {
 133         union inputArgs *inp;
 134         union outputArgs *outp;
 135         int insize, outsize, error;
 136         int offset;
 137
 138         offset = INSIZE(lookup);
 139         insize = max_t(unsigned int, offset + length +1, OUTSIZE(lookup));
 140         UPARG(CODA_LOOKUP);
 141
 142         inp->coda_lookup.VFid = *fid;
 143         inp->coda_lookup.name = offset;
 144         inp->coda_lookup.flags = CLU_CASE_SENSITIVE;
 145         /* send Venus a null terminated string */
 146         memcpy((char *)(inp) + offset, name, length);
 147         *((char *)inp + offset + length) = '\0';
 148
 149         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 150         if (!error) {
 151                 *resfid = outp->coda_lookup.VFid;
 152                 *type = outp->coda_lookup.vtype;
 153         }
 154
 155         CODA_FREE(inp, insize);
 156         return error;
 157 }
 158
 159 int venus_close(struct super_block *sb, struct CodaFid *fid, int flags,
 160                 kuid_t uid)
 161 {
 162         union inputArgs *inp;
 163         union outputArgs *outp;
 164         int insize, outsize, error;
 165
 166         insize = SIZE(release);
 167         UPARG(CODA_CLOSE);
 168
 169         inp->ih.uid = from_kuid(&init_user_ns, uid);
 170         inp->coda_close.VFid = *fid;
 171         inp->coda_close.flags = flags;
 172
 173         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 174
 175         CODA_FREE(inp, insize);
 176         return error;
 177 }
 178
 179 int venus_open(struct super_block *sb, struct CodaFid *fid,
 180                   int flags, struct file **fh)
 181 {
 182         union inputArgs *inp;
 183         union outputArgs *outp;
 184         int insize, outsize, error;
 185
 186         insize = SIZE(open_by_fd);
 187         UPARG(CODA_OPEN_BY_FD);
 188
 189         inp->coda_open_by_fd.VFid = *fid;
 190         inp->coda_open_by_fd.flags = flags;
 191
 192         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 193         if (!error)
 194                 *fh = outp->coda_open_by_fd.fh;
 195
 196         CODA_FREE(inp, insize);
 197         return error;
 198 }
 199
 200 int venus_mkdir(struct super_block *sb, struct CodaFid *dirfid,
 201                    const char *name, int length,
 202                    struct CodaFid *newfid, struct coda_vattr *attrs)
 203 {
 204         union inputArgs *inp;
 205         union outputArgs *outp;
 206         int insize, outsize, error;
 207         int offset;
 208
 209         offset = INSIZE(mkdir);
 210         insize = max_t(unsigned int, offset + length + 1, OUTSIZE(mkdir));
 211         UPARG(CODA_MKDIR);
 212
 213         inp->coda_mkdir.VFid = *dirfid;
 214         inp->coda_mkdir.attr = *attrs;
 215         inp->coda_mkdir.name = offset;
 216         /* Venus must get null terminated string */
 217         memcpy((char *)(inp) + offset, name, length);
 218         *((char *)inp + offset + length) = '\0';
 219
 220         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 221         if (!error) {
 222                 *attrs = outp->coda_mkdir.attr;
 223                 *newfid = outp->coda_mkdir.VFid;
 224         }
 225
 226         CODA_FREE(inp, insize);
 227         return error;
 228 }
 229
 230
 231 int venus_rename(struct super_block *sb, struct CodaFid *old_fid,
 232                  struct CodaFid *new_fid, size_t old_length,
 233                  size_t new_length, const char *old_name,
 234                  const char *new_name)
 235 {
 236         union inputArgs *inp;
 237         union outputArgs *outp;
 238         int insize, outsize, error;
 239         int offset, s;
 240
 241         offset = INSIZE(rename);
 242         insize = max_t(unsigned int, offset + new_length + old_length + 8,
 243                      OUTSIZE(rename));
 244         UPARG(CODA_RENAME);
 245
 246         inp->coda_rename.sourceFid = *old_fid;
 247         inp->coda_rename.destFid =  *new_fid;
 248         inp->coda_rename.srcname = offset;
 249
 250         /* Venus must receive an null terminated string */
 251         s = ( old_length & ~0x3) +4; /* round up to word boundary */
 252         memcpy((char *)(inp) + offset, old_name, old_length);
 253         *((char *)inp + offset + old_length) = '\0';
 254
 255         /* another null terminated string for Venus */
 256         offset += s;
 257         inp->coda_rename.destname = offset;
 258         s = ( new_length & ~0x3) +4; /* round up to word boundary */
 259         memcpy((char *)(inp) + offset, new_name, new_length);
 260         *((char *)inp + offset + new_length) = '\0';
 261
 262         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 263
 264         CODA_FREE(inp, insize);
 265         return error;
 266 }
 267
 268 int venus_create(struct super_block *sb, struct CodaFid *dirfid,
 269                  const char *name, int length, int excl, int mode,
 270                  struct CodaFid *newfid, struct coda_vattr *attrs)
 271 {
 272         union inputArgs *inp;
 273         union outputArgs *outp;
 274         int insize, outsize, error;
 275         int offset;
 276
 277         offset = INSIZE(create);
 278         insize = max_t(unsigned int, offset + length + 1, OUTSIZE(create));
 279         UPARG(CODA_CREATE);
 280
 281         inp->coda_create.VFid = *dirfid;
 282         inp->coda_create.attr.va_mode = mode;
 283         inp->coda_create.excl = excl;
 284         inp->coda_create.mode = mode;
 285         inp->coda_create.name = offset;
 286
 287         /* Venus must get null terminated string */
 288         memcpy((char *)(inp) + offset, name, length);
 289         *((char *)inp + offset + length) = '\0';
 290
 291         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 292         if (!error) {
 293                 *attrs = outp->coda_create.attr;
 294                 *newfid = outp->coda_create.VFid;
 295         }
 296
 297         CODA_FREE(inp, insize);
 298         return error;
 299 }
 300
 301 int venus_rmdir(struct super_block *sb, struct CodaFid *dirfid,
 302                     const char *name, int length)
 303 {
 304         union inputArgs *inp;
 305         union outputArgs *outp;
 306         int insize, outsize, error;
 307         int offset;
 308
 309         offset = INSIZE(rmdir);
 310         insize = max_t(unsigned int, offset + length + 1, OUTSIZE(rmdir));
 311         UPARG(CODA_RMDIR);
 312
 313         inp->coda_rmdir.VFid = *dirfid;
 314         inp->coda_rmdir.name = offset;
 315         memcpy((char *)(inp) + offset, name, length);
 316         *((char *)inp + offset + length) = '\0';
 317
 318         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 319
 320         CODA_FREE(inp, insize);
 321         return error;
 322 }
 323
 324 int venus_remove(struct super_block *sb, struct CodaFid *dirfid,
 325                     const char *name, int length)
 326 {
 327         union inputArgs *inp;
 328         union outputArgs *outp;
 329         int error=0, insize, outsize, offset;
 330
 331         offset = INSIZE(remove);
 332         insize = max_t(unsigned int, offset + length + 1, OUTSIZE(remove));
 333         UPARG(CODA_REMOVE);
 334
 335         inp->coda_remove.VFid = *dirfid;
 336         inp->coda_remove.name = offset;
 337         memcpy((char *)(inp) + offset, name, length);
 338         *((char *)inp + offset + length) = '\0';
 339
 340         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 341
 342         CODA_FREE(inp, insize);
 343         return error;
 344 }
 345
 346 int venus_readlink(struct super_block *sb, struct CodaFid *fid,
 347                       char *buffer, int *length)
 348 {
 349         union inputArgs *inp;
 350         union outputArgs *outp;
 351         int insize, outsize, error;
 352         int retlen;
 353         char *result;
 354
 355         insize = max_t(unsigned int,
 356                      INSIZE(readlink), OUTSIZE(readlink)+ *length);
 357         UPARG(CODA_READLINK);
 358
 359         inp->coda_readlink.VFid = *fid;
 360
 361         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 362         if (!error) {
 363                 retlen = outp->coda_readlink.count;
 364                 if (retlen >= *length)
 365                         retlen = *length - 1;
 366                 *length = retlen;
 367                 result =  (char *)outp + (long)outp->coda_readlink.data;
 368                 memcpy(buffer, result, retlen);
 369                 *(buffer + retlen) = '\0';
 370         }
 371
 372         CODA_FREE(inp, insize);
 373         return error;
 374 }
 375
 376
 377
 378 int venus_link(struct super_block *sb, struct CodaFid *fid,
 379                   struct CodaFid *dirfid, const char *name, int len )
 380 {
 381         union inputArgs *inp;
 382         union outputArgs *outp;
 383         int insize, outsize, error;
 384         int offset;
 385
 386         offset = INSIZE(link);
 387         insize = max_t(unsigned int, offset  + len + 1, OUTSIZE(link));
 388         UPARG(CODA_LINK);
 389
 390         inp->coda_link.sourceFid = *fid;
 391         inp->coda_link.destFid = *dirfid;
 392         inp->coda_link.tname = offset;
 393
 394         /* make sure strings are null terminated */
 395         memcpy((char *)(inp) + offset, name, len);
 396         *((char *)inp + offset + len) = '\0';
 397
 398         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 399
 400         CODA_FREE(inp, insize);
 401         return error;
 402 }
 403
 404 int venus_symlink(struct super_block *sb, struct CodaFid *fid,
 405                      const char *name, int len,
 406                      const char *symname, int symlen)
 407 {
 408         union inputArgs *inp;
 409         union outputArgs *outp;
 410         int insize, outsize, error;
 411         int offset, s;
 412
 413         offset = INSIZE(symlink);
 414         insize = max_t(unsigned int, offset + len + symlen + 8, OUTSIZE(symlink));
 415         UPARG(CODA_SYMLINK);
 416
 417         /*        inp->coda_symlink.attr = *tva; XXXXXX */
 418         inp->coda_symlink.VFid = *fid;
 419
 420         /* Round up to word boundary and null terminate */
 421         inp->coda_symlink.srcname = offset;
 422         s = ( symlen  & ~0x3 ) + 4;
 423         memcpy((char *)(inp) + offset, symname, symlen);
 424         *((char *)inp + offset + symlen) = '\0';
 425
 426         /* Round up to word boundary and null terminate */
 427         offset += s;
 428         inp->coda_symlink.tname = offset;
 429         s = (len & ~0x3) + 4;
 430         memcpy((char *)(inp) + offset, name, len);
 431         *((char *)inp + offset + len) = '\0';
 432
 433         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 434
 435         CODA_FREE(inp, insize);
 436         return error;
 437 }
 438
 439 int venus_fsync(struct super_block *sb, struct CodaFid *fid)
 440 {
 441         union inputArgs *inp;
 442         union outputArgs *outp;
 443         int insize, outsize, error;
 444
 445         insize=SIZE(fsync);
 446         UPARG(CODA_FSYNC);
 447
 448         inp->coda_fsync.VFid = *fid;
 449         error = coda_upcall(coda_vcp(sb), sizeof(union inputArgs),
 450                             &outsize, inp);
 451
 452         CODA_FREE(inp, insize);
 453         return error;
 454 }
 455
 456 int venus_access(struct super_block *sb, struct CodaFid *fid, int mask)
 457 {
 458         union inputArgs *inp;
 459         union outputArgs *outp;
 460         int insize, outsize, error;
 461
 462         insize = SIZE(access);
 463         UPARG(CODA_ACCESS);
 464
 465         inp->coda_access.VFid = *fid;
 466         inp->coda_access.flags = mask;
 467
 468         error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
 469
 470         CODA_FREE(inp, insize);
 471         return error;
 472 }
 473
 474
 475 int venus_pioctl(struct super_block *sb, struct CodaFid *fid,
 476                  unsigned int cmd, struct PioctlData *data)
 477 {
 478         union inputArgs *inp;
 479         union outputArgs *outp;
 480         int insize, outsize, error;
 481         int iocsize;
 482
 483         insize = VC_MAXMSGSIZE;
 484         UPARG(CODA_IOCTL);
 485
 486         /* build packet for Venus */
 487         if (data->vi.in_size > VC_MAXDATASIZE) {
 488                 error = -EINVAL;
 489                 goto exit;
 490         }
 491
 492         if (data->vi.out_size > VC_MAXDATASIZE) {
 493                 error = -EINVAL;
 494                 goto exit;
 495         }
 496
 497         inp->coda_ioctl.VFid = *fid;
 498
 499         /* the cmd field was mutated by increasing its size field to
 500          * reflect the path and follow args. We need to subtract that
 501          * out before sending the command to Venus.  */
 502         inp->coda_ioctl.cmd = (cmd & ~(PIOCPARM_MASK << 16));
 503         iocsize = ((cmd >> 16) & PIOCPARM_MASK) - sizeof(char *) - sizeof(int);
 504         inp->coda_ioctl.cmd |= (iocsize & PIOCPARM_MASK) <<     16;
 505
 506         /* in->coda_ioctl.rwflag = flag; */
 507         inp->coda_ioctl.len = data->vi.in_size;
 508         inp->coda_ioctl.data = (char *)(INSIZE(ioctl));
 509
 510         /* get the data out of user space */
 511         if (copy_from_user((char *)inp + (long)inp->coda_ioctl.data,
 512                            data->vi.in, data->vi.in_size)) {
 513                 error = -EINVAL;
 514                 goto exit;
 515         }
 516
 517         error = coda_upcall(coda_vcp(sb), SIZE(ioctl) + data->vi.in_size,
 518                             &outsize, inp);
 519
 520         if (error) {
 521                 pr_warn("%s: Venus returns: %d for %s\n",
 522                         __func__, error, coda_f2s(fid));
 523                 goto exit;
 524         }
 525
 526         if (outsize < (long)outp->coda_ioctl.data + outp->coda_ioctl.len) {
 527                 error = -EINVAL;
 528                 goto exit;
 529         }
 530
 531         /* Copy out the OUT buffer. */
 532         if (outp->coda_ioctl.len > data->vi.out_size) {
 533                 error = -EINVAL;
 534                 goto exit;
 535         }
 536
 537         /* Copy out the OUT buffer. */
 538         if (copy_to_user(data->vi.out,
 539                          (char *)outp + (long)outp->coda_ioctl.data,
 540                          outp->coda_ioctl.len)) {
 541                 error = -EFAULT;
 542                 goto exit;
 543         }
 544
 545  exit:
 546         CODA_FREE(inp, insize);
 547         return error;
 548 }
 549
 550 int venus_statfs(struct dentry *dentry, struct kstatfs *sfs)
 551 {
 552         union inputArgs *inp;
 553         union outputArgs *outp;
 554         int insize, outsize, error;
 555
 556         insize = max_t(unsigned int, INSIZE(statfs), OUTSIZE(statfs));
 557         UPARG(CODA_STATFS);
 558
 559         error = coda_upcall(coda_vcp(dentry->d_sb), insize, &outsize, inp);
 560         if (!error) {
 561                 sfs->f_blocks = outp->coda_statfs.stat.f_blocks;
 562                 sfs->f_bfree  = outp->coda_statfs.stat.f_bfree;
 563                 sfs->f_bavail = outp->coda_statfs.stat.f_bavail;
 564                 sfs->f_files  = outp->coda_statfs.stat.f_files;
 565                 sfs->f_ffree  = outp->coda_statfs.stat.f_ffree;
 566         }
 567
 568         CODA_FREE(inp, insize);
 569         return error;
 570 }
 571
 572 /*
 573  * coda_upcall and coda_downcall routines.
 574  */
 575 static void coda_block_signals(sigset_t *old)
 576 {
 577         spin_lock_irq(&current->sighand->siglock);
 578         *old = current->blocked;
 579
 580         sigfillset(&current->blocked);
 581         sigdelset(&current->blocked, SIGKILL);
 582         sigdelset(&current->blocked, SIGSTOP);
 583         sigdelset(&current->blocked, SIGINT);
 584
 585         recalc_sigpending();
 586         spin_unlock_irq(&current->sighand->siglock);
 587 }
 588
 589 static void coda_unblock_signals(sigset_t *old)
 590 {
 591         spin_lock_irq(&current->sighand->siglock);
 592         current->blocked = *old;
 593         recalc_sigpending();
 594         spin_unlock_irq(&current->sighand->siglock);
 595 }
 596
 597 /* Don't allow signals to interrupt the following upcalls before venus
 598  * has seen them,
 599  * - CODA_CLOSE or CODA_RELEASE upcall  (to avoid reference count problems)
 600  * - CODA_STORE                         (to avoid data loss)
 601  */
 602 #define CODA_INTERRUPTIBLE(r) (!coda_hard && \
 603                                (((r)->uc_opcode != CODA_CLOSE && \
 604                                  (r)->uc_opcode != CODA_STORE && \
 605                                  (r)->uc_opcode != CODA_RELEASE) || \
 606                                 (r)->uc_flags & CODA_REQ_READ))
 607
 608 static inline void coda_waitfor_upcall(struct venus_comm *vcp,
 609                                        struct upc_req *req)
 610 {
 611         DECLARE_WAITQUEUE(wait, current);
 612         unsigned long timeout = jiffies + coda_timeout * HZ;
 613         sigset_t old;
 614         int blocked;
 615
 616         coda_block_signals(&old);
 617         blocked = 1;
 618
 619         add_wait_queue(&req->uc_sleep, &wait);
 620         for (;;) {
 621                 if (CODA_INTERRUPTIBLE(req))
 622                         set_current_state(TASK_INTERRUPTIBLE);
 623                 else
 624                         set_current_state(TASK_UNINTERRUPTIBLE);
 625
 626                 /* got a reply */
 627                 if (req->uc_flags & (CODA_REQ_WRITE | CODA_REQ_ABORT))
 628                         break;
 629
 630                 if (blocked && time_after(jiffies, timeout) &&
 631                     CODA_INTERRUPTIBLE(req))
 632                 {
 633                         coda_unblock_signals(&old);
 634                         blocked = 0;
 635                 }
 636
 637                 if (signal_pending(current)) {
 638                         list_del(&req->uc_chain);
 639                         break;
 640                 }
 641
 642                 mutex_unlock(&vcp->vc_mutex);
 643                 if (blocked)
 644                         schedule_timeout(HZ);
 645                 else
 646                         schedule();
 647                 mutex_lock(&vcp->vc_mutex);
 648         }
 649         if (blocked)
 650                 coda_unblock_signals(&old);
 651
 652         remove_wait_queue(&req->uc_sleep, &wait);
 653         set_current_state(TASK_RUNNING);
 654 }
 655
 656
 657 /*
 658  * coda_upcall will return an error in the case of
 659  * failed communication with Venus _or_ will peek at Venus
 660  * reply and return Venus' error.
 661  *
 662  * As venus has 2 types of errors, normal errors (positive) and internal
 663  * errors (negative), normal errors are negated, while internal errors
 664  * are all mapped to -EINTR, while showing a nice warning message. (jh)
 665  */
 666 static int coda_upcall(struct venus_comm *vcp,
 667                        int inSize, int *outSize,
 668                        union inputArgs *buffer)
 669 {
 670         union outputArgs *out;
 671         union inputArgs *sig_inputArgs;
 672         struct upc_req *req = NULL, *sig_req;
 673         int error;
 674
 675         mutex_lock(&vcp->vc_mutex);
 676
 677         if (!vcp->vc_inuse) {
 678                 pr_notice("Venus dead, not sending upcall\n");
 679                 error = -ENXIO;
 680                 goto exit;
 681         }
 682
 683         /* Format the request message. */
 684         req = kmalloc(sizeof(struct upc_req), GFP_KERNEL);
 685         if (!req) {
 686                 error = -ENOMEM;
 687                 goto exit;
 688         }
 689
 690         req->uc_data = (void *)buffer;
 691         req->uc_flags = 0;
 692         req->uc_inSize = inSize;
 693         req->uc_outSize = *outSize ? *outSize : inSize;
 694         req->uc_opcode = ((union inputArgs *)buffer)->ih.opcode;
 695         req->uc_unique = ++vcp->vc_seq;
 696         init_waitqueue_head(&req->uc_sleep);
 697
 698         /* Fill in the common input args. */
 699         ((union inputArgs *)buffer)->ih.unique = req->uc_unique;
 700
 701         /* Append msg to pending queue and poke Venus. */
 702         list_add_tail(&req->uc_chain, &vcp->vc_pending);
 703
 704         wake_up_interruptible(&vcp->vc_waitq);
 705         /* We can be interrupted while we wait for Venus to process
 706          * our request.  If the interrupt occurs before Venus has read
 707          * the request, we dequeue and return. If it occurs after the
 708          * read but before the reply, we dequeue, send a signal
 709          * message, and return. If it occurs after the reply we ignore
 710          * it. In no case do we want to restart the syscall.  If it
 711          * was interrupted by a venus shutdown (psdev_close), return
 712          * ENODEV.  */
 713
 714         /* Go to sleep.  Wake up on signals only after the timeout. */
 715         coda_waitfor_upcall(vcp, req);
 716
 717         /* Op went through, interrupt or not... */
 718         if (req->uc_flags & CODA_REQ_WRITE) {
 719                 out = (union outputArgs *)req->uc_data;
 720                 /* here we map positive Venus errors to kernel errors */
 721                 error = -out->oh.result;
 722                 *outSize = req->uc_outSize;
 723                 goto exit;
 724         }
 725
 726         error = -EINTR;
 727         if ((req->uc_flags & CODA_REQ_ABORT) || !signal_pending(current)) {
 728                 pr_warn("Unexpected interruption.\n");
 729                 goto exit;
 730         }
 731
 732         /* Interrupted before venus read it. */
 733         if (!(req->uc_flags & CODA_REQ_READ))
 734                 goto exit;
 735
 736         /* Venus saw the upcall, make sure we can send interrupt signal */
 737         if (!vcp->vc_inuse) {
 738                 pr_info("Venus dead, not sending signal.\n");
 739                 goto exit;
 740         }
 741
 742         error = -ENOMEM;
 743         sig_req = kmalloc(sizeof(struct upc_req), GFP_KERNEL);
 744         if (!sig_req) goto exit;
 745
 746         CODA_ALLOC((sig_req->uc_data), char *, sizeof(struct coda_in_hdr));
 747         if (!sig_req->uc_data) {
 748                 kfree(sig_req);
 749                 goto exit;
 750         }
 751
 752         error = -EINTR;
 753         sig_inputArgs = (union inputArgs *)sig_req->uc_data;
 754         sig_inputArgs->ih.opcode = CODA_SIGNAL;
 755         sig_inputArgs->ih.unique = req->uc_unique;
 756
 757         sig_req->uc_flags = CODA_REQ_ASYNC;
 758         sig_req->uc_opcode = sig_inputArgs->ih.opcode;
 759         sig_req->uc_unique = sig_inputArgs->ih.unique;
 760         sig_req->uc_inSize = sizeof(struct coda_in_hdr);
 761         sig_req->uc_outSize = sizeof(struct coda_in_hdr);
 762
 763         /* insert at head of queue! */
 764         list_add(&(sig_req->uc_chain), &vcp->vc_pending);
 765         wake_up_interruptible(&vcp->vc_waitq);
 766
 767 exit:
 768         kfree(req);
 769         mutex_unlock(&vcp->vc_mutex);
 770         return error;
 771 }
 772
 773 /*
 774     The statements below are part of the Coda opportunistic
 775     programming -- taken from the Mach/BSD kernel code for Coda.
 776     You don't get correct semantics by stating what needs to be
 777     done without guaranteeing the invariants needed for it to happen.
 778     When will be have time to find out what exactly is going on?  (pjb)
 779 */
 780
 781
 782 /*
 783  * There are 7 cases where cache invalidations occur.  The semantics
 784  *  of each is listed here:
 785  *
 786  * CODA_FLUSH     -- flush all entries from the name cache and the cnode cache.
 787  * CODA_PURGEUSER -- flush all entries from the name cache for a specific user
 788  *                  This call is a result of token expiration.
 789  *
 790  * The next arise as the result of callbacks on a file or directory.
 791  * CODA_ZAPFILE   -- flush the cached attributes for a file.
 792
 793  * CODA_ZAPDIR    -- flush the attributes for the dir and
 794  *                  force a new lookup for all the children
 795                     of this dir.
 796
 797  *
 798  * The next is a result of Venus detecting an inconsistent file.
 799  * CODA_PURGEFID  -- flush the attribute for the file
 800  *                  purge it and its children from the dcache
 801  *
 802  * The last  allows Venus to replace local fids with global ones
 803  * during reintegration.
 804  *
 805  * CODA_REPLACE -- replace one CodaFid with another throughout the name cache */
 806
 807 int coda_downcall(struct venus_comm *vcp, int opcode, union outputArgs *out)
 808 {
 809         struct inode *inode = NULL;
 810         struct CodaFid *fid = NULL, *newfid;
 811         struct super_block *sb;
 812
 813         /* Handle invalidation requests. */
 814         mutex_lock(&vcp->vc_mutex);
 815         sb = vcp->vc_sb;
 816         if (!sb || !sb->s_root)
 817                 goto unlock_out;
 818
 819         switch (opcode) {
 820         case CODA_FLUSH:
 821                 coda_cache_clear_all(sb);
 822                 shrink_dcache_sb(sb);
 823                 if (d_really_is_positive(sb->s_root))
 824                         coda_flag_inode(d_inode(sb->s_root), C_FLUSH);
 825                 break;
 826
 827         case CODA_PURGEUSER:
 828                 coda_cache_clear_all(sb);
 829                 break;
 830
 831         case CODA_ZAPDIR:
 832                 fid = &out->coda_zapdir.CodaFid;
 833                 break;
 834
 835         case CODA_ZAPFILE:
 836                 fid = &out->coda_zapfile.CodaFid;
 837                 break;
 838
 839         case CODA_PURGEFID:
 840                 fid = &out->coda_purgefid.CodaFid;
 841                 break;
 842
 843         case CODA_REPLACE:
 844                 fid = &out->coda_replace.OldFid;
 845                 break;
 846         }
 847         if (fid)
 848                 inode = coda_fid_to_inode(fid, sb);
 849
 850 unlock_out:
 851         mutex_unlock(&vcp->vc_mutex);
 852
 853         if (!inode)
 854                 return 0;
 855
 856         switch (opcode) {
 857         case CODA_ZAPDIR:
 858                 coda_flag_inode_children(inode, C_PURGE);
 859                 coda_flag_inode(inode, C_VATTR);
 860                 break;
 861
 862         case CODA_ZAPFILE:
 863                 coda_flag_inode(inode, C_VATTR);
 864                 break;
 865
 866         case CODA_PURGEFID:
 867                 coda_flag_inode_children(inode, C_PURGE);
 868
 869                 /* catch the dentries later if some are still busy */
 870                 coda_flag_inode(inode, C_PURGE);
 871                 d_prune_aliases(inode);
 872                 break;
 873
 874         case CODA_REPLACE:
 875                 newfid = &out->coda_replace.NewFid;
 876                 coda_replace_fid(inode, fid, newfid);
 877                 break;
 878         }
 879         iput(inode);
 880         return 0;
 881 }
 882