source/modules/vfs_aio_fork.c

   1 /*
   2  * Simulate the Posix AIO using mmap/fork
   3  *
   4  * Copyright (C) Volker Lendecke 2008
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include "includes.h"
  22
  23 struct mmap_area {
  24         size_t size;
  25         volatile void *ptr;
  26 };
  27
  28 static int mmap_area_destructor(struct mmap_area *area)
  29 {
  30         munmap((void *)area->ptr, area->size);
  31         return 0;
  32 }
  33
  34 static struct mmap_area *mmap_area_init(TALLOC_CTX *mem_ctx, size_t size)
  35 {
  36         struct mmap_area *result;
  37         int fd;
  38
  39         result = talloc(mem_ctx, struct mmap_area);
  40         if (result == NULL) {
  41                 DEBUG(0, ("talloc failed\n"));
  42                 goto fail;
  43         }
  44
  45         fd = open("/dev/zero", O_RDWR);
  46         if (fd == -1) {
  47                 DEBUG(3, ("open(\"/dev/zero\") failed: %s\n",
  48                           strerror(errno)));
  49                 goto fail;
  50         }
  51
  52         result->ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
  53                            MAP_SHARED|MAP_FILE, fd, 0);
  54         if (result->ptr == MAP_FAILED) {
  55                 DEBUG(1, ("mmap failed: %s\n", strerror(errno)));
  56                 goto fail;
  57         }
  58
  59         result->size = size;
  60         talloc_set_destructor(result, mmap_area_destructor);
  61
  62         return result;
  63
  64 fail:
  65         TALLOC_FREE(result);
  66         return NULL;
  67 }
  68
  69 struct rw_cmd {
  70         size_t n;
  71         SMB_OFF_T offset;
  72         bool read_cmd;
  73 };
  74
  75 struct rw_ret {
  76         ssize_t size;
  77         int ret_errno;
  78 };
  79
  80 struct aio_child_list;
  81
  82 struct aio_child {
  83         struct aio_child *prev, *next;
  84         struct aio_child_list *list;
  85         SMB_STRUCT_AIOCB *aiocb;
  86         pid_t pid;
  87         int sockfd;
  88         struct fd_event *sock_event;
  89         struct rw_ret retval;
  90         struct mmap_area *map;  /* ==NULL means write request */
  91         bool dont_delete;       /* Marked as in use since last cleanup */
  92         bool cancelled;
  93         bool read_cmd;
  94 };
  95
  96 struct aio_child_list {
  97         struct aio_child *children;
  98         struct timed_event *cleanup_event;
  99 };
 100
 101 static void free_aio_children(void **p)
 102 {
 103         TALLOC_FREE(*p);
 104 }
 105
 106 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
 107 {
 108         struct msghdr msg;
 109         struct iovec iov[1];
 110         ssize_t n;
 111 #ifndef HAVE_MSGHDR_MSG_CONTROL
 112         int newfd;
 113 #endif
 114
 115 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 116         union {
 117           struct cmsghdr        cm;
 118           char                          control[CMSG_SPACE(sizeof(int))];
 119         } control_un;
 120         struct cmsghdr  *cmptr;
 121
 122         msg.msg_control = control_un.control;
 123         msg.msg_controllen = sizeof(control_un.control);
 124 #else
 125 #if HAVE_MSGHDR_MSG_ACCTRIGHTS
 126         msg.msg_accrights = (caddr_t) &newfd;
 127         msg.msg_accrightslen = sizeof(int);
 128 #else
 129 #error Can not pass file descriptors
 130 #endif
 131 #endif
 132
 133         msg.msg_name = NULL;
 134         msg.msg_namelen = 0;
 135
 136         iov[0].iov_base = ptr;
 137         iov[0].iov_len = nbytes;
 138         msg.msg_iov = iov;
 139         msg.msg_iovlen = 1;
 140
 141         if ( (n = recvmsg(fd, &msg, 0)) <= 0) {
 142                 return(n);
 143         }
 144
 145 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 146         if ((cmptr = CMSG_FIRSTHDR(&msg)) != NULL
 147             && cmptr->cmsg_len == CMSG_LEN(sizeof(int))) {
 148                 if (cmptr->cmsg_level != SOL_SOCKET) {
 149                         DEBUG(10, ("control level != SOL_SOCKET"));
 150                         errno = EINVAL;
 151                         return -1;
 152                 }
 153                 if (cmptr->cmsg_type != SCM_RIGHTS) {
 154                         DEBUG(10, ("control type != SCM_RIGHTS"));
 155                         errno = EINVAL;
 156                         return -1;
 157                 }
 158                 *recvfd = *((int *) CMSG_DATA(cmptr));
 159         } else {
 160                 *recvfd = -1;           /* descriptor was not passed */
 161         }
 162 #else
 163         if (msg.msg_accrightslen == sizeof(int)) {
 164                 *recvfd = newfd;
 165         }
 166         else {
 167                 *recvfd = -1;           /* descriptor was not passed */
 168         }
 169 #endif
 170
 171         return(n);
 172 }
 173
 174 static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd)
 175 {
 176         struct msghdr   msg;
 177         struct iovec    iov[1];
 178
 179 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 180         union {
 181                 struct cmsghdr  cm;
 182                 char control[CMSG_SPACE(sizeof(int))];
 183         } control_un;
 184         struct cmsghdr  *cmptr;
 185
 186         ZERO_STRUCT(msg);
 187         ZERO_STRUCT(control_un);
 188
 189         msg.msg_control = control_un.control;
 190         msg.msg_controllen = sizeof(control_un.control);
 191
 192         cmptr = CMSG_FIRSTHDR(&msg);
 193         cmptr->cmsg_len = CMSG_LEN(sizeof(int));
 194         cmptr->cmsg_level = SOL_SOCKET;
 195         cmptr->cmsg_type = SCM_RIGHTS;
 196         *((int *) CMSG_DATA(cmptr)) = sendfd;
 197 #else
 198         ZERO_STRUCT(msg);
 199         msg.msg_accrights = (caddr_t) &sendfd;
 200         msg.msg_accrightslen = sizeof(int);
 201 #endif
 202
 203         msg.msg_name = NULL;
 204         msg.msg_namelen = 0;
 205
 206         ZERO_STRUCT(iov);
 207         iov[0].iov_base = ptr;
 208         iov[0].iov_len = nbytes;
 209         msg.msg_iov = iov;
 210         msg.msg_iovlen = 1;
 211
 212         return (sendmsg(fd, &msg, 0));
 213 }
 214
 215 static void aio_child_cleanup(struct event_context *event_ctx,
 216                               struct timed_event *te,
 217                               const struct timeval *now,
 218                               void *private_data)
 219 {
 220         struct aio_child_list *list = talloc_get_type_abort(
 221                 private_data, struct aio_child_list);
 222         struct aio_child *child, *next;
 223
 224         TALLOC_FREE(list->cleanup_event);
 225
 226         for (child = list->children; child != NULL; child = next) {
 227                 next = child->next;
 228
 229                 if (child->aiocb != NULL) {
 230                         DEBUG(10, ("child %d currently active\n",
 231                                    (int)child->pid));
 232                         continue;
 233                 }
 234
 235                 if (child->dont_delete) {
 236                         DEBUG(10, ("Child %d was active since last cleanup\n",
 237                                    (int)child->pid));
 238                         child->dont_delete = false;
 239                         continue;
 240                 }
 241
 242                 DEBUG(10, ("Child %d idle for more than 30 seconds, "
 243                            "deleting\n", (int)child->pid));
 244
 245                 TALLOC_FREE(child);
 246         }
 247
 248         if (list->children != NULL) {
 249                 /*
 250                  * Re-schedule the next cleanup round
 251                  */
 252                 list->cleanup_event = event_add_timed(smbd_event_context(), list,
 253                                                       timeval_add(now, 30, 0),
 254                                                       "aio_child_cleanup",
 255                                                       aio_child_cleanup, list);
 256
 257         }
 258 }
 259
 260 static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle)
 261 {
 262         struct aio_child_list *data = NULL;
 263
 264         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 265                 SMB_VFS_HANDLE_GET_DATA(handle, data, struct aio_child_list,
 266                                         return NULL);
 267         }
 268
 269         if (data == NULL) {
 270                 data = TALLOC_ZERO_P(NULL, struct aio_child_list);
 271                 if (data == NULL) {
 272                         return NULL;
 273                 }
 274         }
 275
 276         /*
 277          * Regardless of whether the child_list had been around or not, make
 278          * sure that we have a cleanup timed event. This timed event will
 279          * delete itself when it finds that no children are around anymore.
 280          */
 281
 282         if (data->cleanup_event == NULL) {
 283                 data->cleanup_event = event_add_timed(smbd_event_context(), data,
 284                                                       timeval_current_ofs(30, 0),
 285                                                       "aio_child_cleanup",
 286                                                       aio_child_cleanup, data);
 287                 if (data->cleanup_event == NULL) {
 288                         TALLOC_FREE(data);
 289                         return NULL;
 290                 }
 291         }
 292
 293         if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
 294                 SMB_VFS_HANDLE_SET_DATA(handle, data, free_aio_children,
 295                                         struct aio_child_list, return False);
 296         }
 297
 298         return data;
 299 }
 300
 301 static void aio_child_loop(int sockfd, struct mmap_area *map)
 302 {
 303         while (true) {
 304                 int fd = -1;
 305                 ssize_t ret;
 306                 struct rw_cmd cmd_struct;
 307                 struct rw_ret ret_struct;
 308
 309                 ret = read_fd(sockfd, &cmd_struct, sizeof(cmd_struct), &fd);
 310                 if (ret != sizeof(cmd_struct)) {
 311                         DEBUG(10, ("read_fd returned %d: %s\n", (int)ret,
 312                                    strerror(errno)));
 313                         exit(1);
 314                 }
 315
 316                 DEBUG(10, ("aio_child_loop: %s %d bytes at %d from fd %d\n",
 317                            cmd_struct.read_cmd ? "read" : "write",
 318                            (int)cmd_struct.n, (int)cmd_struct.offset, fd));
 319
 320 #ifdef ENABLE_BUILD_FARM_HACKS
 321                 {
 322                         /*
 323                          * In the build farm, we want erratic behaviour for
 324                          * async I/O times
 325                          */
 326                         uint8_t randval;
 327                         unsigned msecs;
 328                         /*
 329                          * use generate_random_buffer, we just forked from a
 330                          * common parent state
 331                          */
 332                         generate_random_buffer(&randval, sizeof(randval));
 333                         msecs = randval + 20;
 334                         DEBUG(10, ("delaying for %u msecs\n", msecs));
 335                         smb_msleep(msecs);
 336                 }
 337 #endif
 338
 339
 340                 ZERO_STRUCT(ret_struct);
 341
 342                 if (cmd_struct.read_cmd) {
 343                         ret_struct.size = sys_pread(
 344                                 fd, (void *)map->ptr, cmd_struct.n,
 345                                 cmd_struct.offset);
 346                 }
 347                 else {
 348                         ret_struct.size = sys_pwrite(
 349                                 fd, (void *)map->ptr, cmd_struct.n,
 350                                 cmd_struct.offset);
 351                 }
 352
 353                 DEBUG(10, ("aio_child_loop: syscall returned %d\n",
 354                            (int)ret_struct.size));
 355
 356                 if (ret_struct.size == -1) {
 357                         ret_struct.ret_errno = errno;
 358                 }
 359
 360                 ret = write_data(sockfd, (char *)&ret_struct,
 361                                  sizeof(ret_struct));
 362                 if (ret != sizeof(ret_struct)) {
 363                         DEBUG(10, ("could not write ret_struct: %s\n",
 364                                    strerror(errno)));
 365                         exit(2);
 366                 }
 367
 368                 close(fd);
 369         }
 370 }
 371
 372 static void handle_aio_completion(struct event_context *event_ctx,
 373                                   struct fd_event *event, uint16 flags,
 374                                   void *p)
 375 {
 376         struct aio_child *child = (struct aio_child *)p;
 377         uint16 mid;
 378
 379         DEBUG(10, ("handle_aio_completion called with flags=%d\n", flags));
 380
 381         if ((flags & EVENT_FD_READ) == 0) {
 382                 return;
 383         }
 384
 385         if (!NT_STATUS_IS_OK(read_data(child->sockfd,
 386                                        (char *)&child->retval,
 387                                        sizeof(child->retval)))) {
 388                 DEBUG(0, ("aio child %d died\n", (int)child->pid));
 389                 child->retval.size = -1;
 390                 child->retval.ret_errno = EIO;
 391         }
 392
 393         if (child->cancelled) {
 394                 child->aiocb = NULL;
 395                 child->cancelled = false;
 396                 return;
 397         }
 398
 399         if (child->read_cmd && (child->retval.size > 0)) {
 400                 SMB_ASSERT(child->retval.size <= child->aiocb->aio_nbytes);
 401                 memcpy((void *)child->aiocb->aio_buf, (void *)child->map->ptr,
 402                        child->retval.size);
 403         }
 404
 405         mid = child->aiocb->aio_sigevent.sigev_value.sival_int;
 406
 407         DEBUG(10, ("mid %d finished\n", (int)mid));
 408
 409         aio_request_done(mid);
 410         process_aio_queue();
 411 }
 412
 413 static int aio_child_destructor(struct aio_child *child)
 414 {
 415         SMB_ASSERT((child->aiocb == NULL) || child->cancelled);
 416         close(child->sockfd);
 417         DLIST_REMOVE(child->list->children, child);
 418         return 0;
 419 }
 420
 421 static NTSTATUS create_aio_child(struct aio_child_list *children,
 422                                  size_t map_size,
 423                                  struct aio_child **presult)
 424 {
 425         struct aio_child *result;
 426         int fdpair[2];
 427         NTSTATUS status;
 428
 429         fdpair[0] = fdpair[1] = -1;
 430
 431         result = TALLOC_ZERO_P(children, struct aio_child);
 432         NT_STATUS_HAVE_NO_MEMORY(result);
 433
 434         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
 435                 status = map_nt_error_from_unix(errno);
 436                 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
 437                 TALLOC_FREE(result);
 438                 goto fail;
 439         }
 440
 441         DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
 442
 443         result->map = mmap_area_init(result, map_size);
 444         if (result->map == NULL) {
 445                 status = map_nt_error_from_unix(errno);
 446                 DEBUG(0, ("Could not create mmap area\n"));
 447                 goto fail;
 448         }
 449
 450         result->pid = sys_fork();
 451         if (result->pid == -1) {
 452                 status = map_nt_error_from_unix(errno);
 453                 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
 454                 goto fail;
 455         }
 456
 457         if (result->pid == 0) {
 458                 close(fdpair[0]);
 459                 result->sockfd = fdpair[1];
 460                 aio_child_loop(result->sockfd, result->map);
 461         }
 462
 463         DEBUG(10, ("Child %d created\n", result->pid));
 464
 465         result->sockfd = fdpair[0];
 466         close(fdpair[1]);
 467
 468         result->sock_event = event_add_fd(smbd_event_context(), result,
 469                                           result->sockfd, EVENT_FD_READ,
 470                                           handle_aio_completion,
 471                                           result);
 472         if (result->sock_event == NULL) {
 473                 status = NT_STATUS_NO_MEMORY;
 474                 DEBUG(0, ("event_add_fd failed\n"));
 475                 goto fail;
 476         }
 477
 478         result->list = children;
 479         DLIST_ADD(children->children, result);
 480
 481         talloc_set_destructor(result, aio_child_destructor);
 482
 483         *presult = result;
 484
 485         return NT_STATUS_OK;
 486
 487  fail:
 488         if (fdpair[0] != -1) close(fdpair[0]);
 489         if (fdpair[1] != -1) close(fdpair[1]);
 490         TALLOC_FREE(result);
 491
 492         return status;
 493 }
 494
 495 static NTSTATUS get_idle_child(struct vfs_handle_struct *handle,
 496                                struct aio_child **pchild)
 497 {
 498         struct aio_child_list *children;
 499         struct aio_child *child;
 500         NTSTATUS status;
 501
 502         children = init_aio_children(handle);
 503         if (children == NULL) {
 504                 return NT_STATUS_NO_MEMORY;
 505         }
 506
 507         for (child = children->children; child != NULL; child = child->next) {
 508                 if (child->aiocb == NULL) {
 509                         /* idle */
 510                         break;
 511                 }
 512         }
 513
 514         if (child == NULL) {
 515                 DEBUG(10, ("no idle child found, creating new one\n"));
 516
 517                 status = create_aio_child(children, 128*1024, &child);
 518                 if (!NT_STATUS_IS_OK(status)) {
 519                         DEBUG(10, ("create_aio_child failed: %s\n",
 520                                    nt_errstr(status)));
 521                         return status;
 522                 }
 523         }
 524
 525         child->dont_delete = true;
 526
 527         *pchild = child;
 528         return NT_STATUS_OK;
 529 }
 530
 531 static int aio_fork_read(struct vfs_handle_struct *handle,
 532                          struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb)
 533 {
 534         struct aio_child *child;
 535         struct rw_cmd cmd;
 536         ssize_t ret;
 537         NTSTATUS status;
 538
 539         if (aiocb->aio_nbytes > 128*1024) {
 540                 /* TODO: support variable buffers */
 541                 errno = EINVAL;
 542                 return -1;
 543         }
 544
 545         status = get_idle_child(handle, &child);
 546         if (!NT_STATUS_IS_OK(status)) {
 547                 DEBUG(10, ("Could not get an idle child\n"));
 548                 return -1;
 549         }
 550
 551         child->read_cmd = true;
 552         child->aiocb = aiocb;
 553         child->retval.ret_errno = EINPROGRESS;
 554
 555         ZERO_STRUCT(cmd);
 556         cmd.n = aiocb->aio_nbytes;
 557         cmd.offset = aiocb->aio_offset;
 558         cmd.read_cmd = child->read_cmd;
 559
 560         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 561                    (int)child->pid));
 562
 563         ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd);
 564         if (ret == -1) {
 565                 DEBUG(10, ("write_fd failed: %s\n", strerror(errno)));
 566                 return -1;
 567         }
 568
 569         return 0;
 570 }
 571
 572 static int aio_fork_write(struct vfs_handle_struct *handle,
 573                           struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb)
 574 {
 575         struct aio_child *child;
 576         struct rw_cmd cmd;
 577         ssize_t ret;
 578         NTSTATUS status;
 579
 580         if (aiocb->aio_nbytes > 128*1024) {
 581                 /* TODO: support variable buffers */
 582                 errno = EINVAL;
 583                 return -1;
 584         }
 585
 586         status = get_idle_child(handle, &child);
 587         if (!NT_STATUS_IS_OK(status)) {
 588                 DEBUG(10, ("Could not get an idle child\n"));
 589                 return -1;
 590         }
 591
 592         child->read_cmd = false;
 593         child->aiocb = aiocb;
 594         child->retval.ret_errno = EINPROGRESS;
 595
 596         memcpy((void *)child->map->ptr, (void *)aiocb->aio_buf,
 597                aiocb->aio_nbytes);
 598
 599         ZERO_STRUCT(cmd);
 600         cmd.n = aiocb->aio_nbytes;
 601         cmd.offset = aiocb->aio_offset;
 602         cmd.read_cmd = child->read_cmd;
 603
 604         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 605                    (int)child->pid));
 606
 607         ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd);
 608         if (ret == -1) {
 609                 DEBUG(10, ("write_fd failed: %s\n", strerror(errno)));
 610                 return -1;
 611         }
 612
 613         return 0;
 614 }
 615
 616 static struct aio_child *aio_fork_find_child(struct vfs_handle_struct *handle,
 617                                              SMB_STRUCT_AIOCB *aiocb)
 618 {
 619         struct aio_child_list *children;
 620         struct aio_child *child;
 621
 622         children = init_aio_children(handle);
 623         if (children == NULL) {
 624                 return NULL;
 625         }
 626
 627         for (child = children->children; child != NULL; child = child->next) {
 628                 if (child->aiocb == aiocb) {
 629                         return child;
 630                 }
 631         }
 632
 633         return NULL;
 634 }
 635
 636 static ssize_t aio_fork_return_fn(struct vfs_handle_struct *handle,
 637                                   struct files_struct *fsp,
 638                                   SMB_STRUCT_AIOCB *aiocb)
 639 {
 640         struct aio_child *child = aio_fork_find_child(handle, aiocb);
 641
 642         if (child == NULL) {
 643                 errno = EINVAL;
 644                 DEBUG(0, ("returning EINVAL\n"));
 645                 return -1;
 646         }
 647
 648         child->aiocb = NULL;
 649
 650         if (child->retval.size == -1) {
 651                 errno = child->retval.ret_errno;
 652         }
 653
 654         return child->retval.size;
 655 }
 656
 657 static int aio_fork_cancel(struct vfs_handle_struct *handle,
 658                            struct files_struct *fsp,
 659                            SMB_STRUCT_AIOCB *aiocb)
 660 {
 661         struct aio_child_list *children;
 662         struct aio_child *child;
 663
 664         children = init_aio_children(handle);
 665         if (children == NULL) {
 666                 errno = EINVAL;
 667                 return -1;
 668         }
 669
 670         for (child = children->children; child != NULL; child = child->next) {
 671                 if (child->aiocb == NULL) {
 672                         continue;
 673                 }
 674                 if (child->aiocb->aio_fildes != fsp->fh->fd) {
 675                         continue;
 676                 }
 677                 if ((aiocb != NULL) && (child->aiocb != aiocb)) {
 678                         continue;
 679                 }
 680
 681                 /*
 682                  * We let the child do its job, but we discard the result when
 683                  * it's finished.
 684                  */
 685
 686                 child->cancelled = true;
 687         }
 688
 689         return AIO_CANCELED;
 690 }
 691
 692 static int aio_fork_error_fn(struct vfs_handle_struct *handle,
 693                              struct files_struct *fsp,
 694                              SMB_STRUCT_AIOCB *aiocb)
 695 {
 696         struct aio_child *child = aio_fork_find_child(handle, aiocb);
 697
 698         if (child == NULL) {
 699                 errno = EINVAL;
 700                 return -1;
 701         }
 702
 703         return child->retval.ret_errno;
 704 }
 705
 706 /* VFS operations structure */
 707
 708 static vfs_op_tuple aio_fork_ops[] = {
 709         {SMB_VFS_OP(aio_fork_read),     SMB_VFS_OP_AIO_READ,
 710          SMB_VFS_LAYER_TRANSPARENT},
 711         {SMB_VFS_OP(aio_fork_write),    SMB_VFS_OP_AIO_WRITE,
 712          SMB_VFS_LAYER_TRANSPARENT},
 713         {SMB_VFS_OP(aio_fork_return_fn), SMB_VFS_OP_AIO_RETURN,
 714          SMB_VFS_LAYER_TRANSPARENT},
 715         {SMB_VFS_OP(aio_fork_cancel),   SMB_VFS_OP_AIO_CANCEL,
 716          SMB_VFS_LAYER_TRANSPARENT},
 717         {SMB_VFS_OP(aio_fork_error_fn), SMB_VFS_OP_AIO_ERROR,
 718          SMB_VFS_LAYER_TRANSPARENT},
 719         {SMB_VFS_OP(NULL),              SMB_VFS_OP_NOOP,
 720          SMB_VFS_LAYER_NOOP}
 721 };
 722
 723 NTSTATUS vfs_aio_fork_init(void);
 724 NTSTATUS vfs_aio_fork_init(void)
 725 {
 726         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 727                                 "aio_fork", aio_fork_ops);
 728 }