source3/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         close(fd);
  60
  61         result->size = size;
  62         talloc_set_destructor(result, mmap_area_destructor);
  63
  64         return result;
  65
  66 fail:
  67         TALLOC_FREE(result);
  68         return NULL;
  69 }
  70
  71 struct rw_cmd {
  72         size_t n;
  73         SMB_OFF_T offset;
  74         bool read_cmd;
  75 };
  76
  77 struct rw_ret {
  78         ssize_t size;
  79         int ret_errno;
  80 };
  81
  82 struct aio_child_list;
  83
  84 struct aio_child {
  85         struct aio_child *prev, *next;
  86         struct aio_child_list *list;
  87         SMB_STRUCT_AIOCB *aiocb;
  88         pid_t pid;
  89         int sockfd;
  90         struct fd_event *sock_event;
  91         struct rw_ret retval;
  92         struct mmap_area *map;  /* ==NULL means write request */
  93         bool dont_delete;       /* Marked as in use since last cleanup */
  94         bool cancelled;
  95         bool read_cmd;
  96 };
  97
  98 struct aio_child_list {
  99         struct aio_child *children;
 100         struct timed_event *cleanup_event;
 101 };
 102
 103 static void free_aio_children(void **p)
 104 {
 105         TALLOC_FREE(*p);
 106 }
 107
 108 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
 109 {
 110         struct msghdr msg;
 111         struct iovec iov[1];
 112         ssize_t n;
 113 #ifndef HAVE_MSGHDR_MSG_CONTROL
 114         int newfd;
 115 #endif
 116
 117 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 118         union {
 119           struct cmsghdr        cm;
 120           char                          control[CMSG_SPACE(sizeof(int))];
 121         } control_un;
 122         struct cmsghdr  *cmptr;
 123
 124         msg.msg_control = control_un.control;
 125         msg.msg_controllen = sizeof(control_un.control);
 126 #else
 127 #if HAVE_MSGHDR_MSG_ACCTRIGHTS
 128         msg.msg_accrights = (caddr_t) &newfd;
 129         msg.msg_accrightslen = sizeof(int);
 130 #else
 131 #error Can not pass file descriptors
 132 #endif
 133 #endif
 134
 135         msg.msg_name = NULL;
 136         msg.msg_namelen = 0;
 137
 138         iov[0].iov_base = (void *)ptr;
 139         iov[0].iov_len = nbytes;
 140         msg.msg_iov = iov;
 141         msg.msg_iovlen = 1;
 142
 143         if ( (n = recvmsg(fd, &msg, 0)) <= 0) {
 144                 return(n);
 145         }
 146
 147 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 148         if ((cmptr = CMSG_FIRSTHDR(&msg)) != NULL
 149             && cmptr->cmsg_len == CMSG_LEN(sizeof(int))) {
 150                 if (cmptr->cmsg_level != SOL_SOCKET) {
 151                         DEBUG(10, ("control level != SOL_SOCKET"));
 152                         errno = EINVAL;
 153                         return -1;
 154                 }
 155                 if (cmptr->cmsg_type != SCM_RIGHTS) {
 156                         DEBUG(10, ("control type != SCM_RIGHTS"));
 157                         errno = EINVAL;
 158                         return -1;
 159                 }
 160                 *recvfd = *((int *) CMSG_DATA(cmptr));
 161         } else {
 162                 *recvfd = -1;           /* descriptor was not passed */
 163         }
 164 #else
 165         if (msg.msg_accrightslen == sizeof(int)) {
 166                 *recvfd = newfd;
 167         }
 168         else {
 169                 *recvfd = -1;           /* descriptor was not passed */
 170         }
 171 #endif
 172
 173         return(n);
 174 }
 175
 176 static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd)
 177 {
 178         struct msghdr   msg;
 179         struct iovec    iov[1];
 180
 181 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 182         union {
 183                 struct cmsghdr  cm;
 184                 char control[CMSG_SPACE(sizeof(int))];
 185         } control_un;
 186         struct cmsghdr  *cmptr;
 187
 188         ZERO_STRUCT(msg);
 189         ZERO_STRUCT(control_un);
 190
 191         msg.msg_control = control_un.control;
 192         msg.msg_controllen = sizeof(control_un.control);
 193
 194         cmptr = CMSG_FIRSTHDR(&msg);
 195         cmptr->cmsg_len = CMSG_LEN(sizeof(int));
 196         cmptr->cmsg_level = SOL_SOCKET;
 197         cmptr->cmsg_type = SCM_RIGHTS;
 198         *((int *) CMSG_DATA(cmptr)) = sendfd;
 199 #else
 200         ZERO_STRUCT(msg);
 201         msg.msg_accrights = (caddr_t) &sendfd;
 202         msg.msg_accrightslen = sizeof(int);
 203 #endif
 204
 205         msg.msg_name = NULL;
 206         msg.msg_namelen = 0;
 207
 208         ZERO_STRUCT(iov);
 209         iov[0].iov_base = (void *)ptr;
 210         iov[0].iov_len = nbytes;
 211         msg.msg_iov = iov;
 212         msg.msg_iovlen = 1;
 213
 214         return (sendmsg(fd, &msg, 0));
 215 }
 216
 217 static void aio_child_cleanup(struct event_context *event_ctx,
 218                               struct timed_event *te,
 219                               struct timeval now,
 220                               void *private_data)
 221 {
 222         struct aio_child_list *list = talloc_get_type_abort(
 223                 private_data, struct aio_child_list);
 224         struct aio_child *child, *next;
 225
 226         TALLOC_FREE(list->cleanup_event);
 227
 228         for (child = list->children; child != NULL; child = next) {
 229                 next = child->next;
 230
 231                 if (child->aiocb != NULL) {
 232                         DEBUG(10, ("child %d currently active\n",
 233                                    (int)child->pid));
 234                         continue;
 235                 }
 236
 237                 if (child->dont_delete) {
 238                         DEBUG(10, ("Child %d was active since last cleanup\n",
 239                                    (int)child->pid));
 240                         child->dont_delete = false;
 241                         continue;
 242                 }
 243
 244                 DEBUG(10, ("Child %d idle for more than 30 seconds, "
 245                            "deleting\n", (int)child->pid));
 246
 247                 TALLOC_FREE(child);
 248         }
 249
 250         if (list->children != NULL) {
 251                 /*
 252                  * Re-schedule the next cleanup round
 253                  */
 254                 list->cleanup_event = event_add_timed(smbd_event_context(), list,
 255                                                       timeval_add(&now, 30, 0),
 256                                                       aio_child_cleanup, list);
 257
 258         }
 259 }
 260
 261 static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle)
 262 {
 263         struct aio_child_list *data = NULL;
 264
 265         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 266                 SMB_VFS_HANDLE_GET_DATA(handle, data, struct aio_child_list,
 267                                         return NULL);
 268         }
 269
 270         if (data == NULL) {
 271                 data = TALLOC_ZERO_P(NULL, struct aio_child_list);
 272                 if (data == NULL) {
 273                         return NULL;
 274                 }
 275         }
 276
 277         /*
 278          * Regardless of whether the child_list had been around or not, make
 279          * sure that we have a cleanup timed event. This timed event will
 280          * delete itself when it finds that no children are around anymore.
 281          */
 282
 283         if (data->cleanup_event == NULL) {
 284                 data->cleanup_event = event_add_timed(smbd_event_context(), data,
 285                                                       timeval_current_ofs(30, 0),
 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 #ifdef ENABLE_BUILD_FARM_HACKS
 347                         ret_struct.size = MAX(1, ret_struct.size * 0.9);
 348 #endif
 349                 }
 350                 else {
 351                         ret_struct.size = sys_pwrite(
 352                                 fd, (void *)map->ptr, cmd_struct.n,
 353                                 cmd_struct.offset);
 354                 }
 355
 356                 DEBUG(10, ("aio_child_loop: syscall returned %d\n",
 357                            (int)ret_struct.size));
 358
 359                 if (ret_struct.size == -1) {
 360                         ret_struct.ret_errno = errno;
 361                 }
 362
 363                 /*
 364                  * Close the fd before telling our parent we're done. The
 365                  * parent might close and re-open the file very quickly, and
 366                  * with system-level share modes (GPFS) we would get an
 367                  * unjustified SHARING_VIOLATION.
 368                  */
 369                 close(fd);
 370
 371                 ret = write_data(sockfd, (char *)&ret_struct,
 372                                  sizeof(ret_struct));
 373                 if (ret != sizeof(ret_struct)) {
 374                         DEBUG(10, ("could not write ret_struct: %s\n",
 375                                    strerror(errno)));
 376                         exit(2);
 377                 }
 378         }
 379 }
 380
 381 static void handle_aio_completion(struct event_context *event_ctx,
 382                                   struct fd_event *event, uint16 flags,
 383                                   void *p)
 384 {
 385         struct aio_child *child = (struct aio_child *)p;
 386         uint64_t mid;
 387
 388         DEBUG(10, ("handle_aio_completion called with flags=%d\n", flags));
 389
 390         if ((flags & EVENT_FD_READ) == 0) {
 391                 return;
 392         }
 393
 394         if (!NT_STATUS_IS_OK(read_data(child->sockfd,
 395                                        (char *)&child->retval,
 396                                        sizeof(child->retval)))) {
 397                 DEBUG(0, ("aio child %d died\n", (int)child->pid));
 398                 child->retval.size = -1;
 399                 child->retval.ret_errno = EIO;
 400         }
 401
 402         if (child->cancelled) {
 403                 child->aiocb = NULL;
 404                 child->cancelled = false;
 405                 return;
 406         }
 407
 408         if (child->read_cmd && (child->retval.size > 0)) {
 409                 SMB_ASSERT(child->retval.size <= child->aiocb->aio_nbytes);
 410                 memcpy((void *)child->aiocb->aio_buf, (void *)child->map->ptr,
 411                        child->retval.size);
 412         }
 413
 414         /* FIXME - this won't work for SMB2. */
 415         mid = (uint64_t)child->aiocb->aio_sigevent.sigev_value.sival_int;
 416
 417         DEBUG(10, ("mid %d finished\n", (int)mid));
 418
 419         smbd_aio_complete_mid(mid);
 420 }
 421
 422 static int aio_child_destructor(struct aio_child *child)
 423 {
 424         SMB_ASSERT((child->aiocb == NULL) || child->cancelled);
 425         close(child->sockfd);
 426         DLIST_REMOVE(child->list->children, child);
 427         return 0;
 428 }
 429
 430 /*
 431  * We have to close all fd's in open files, we might incorrectly hold a system
 432  * level share mode on a file.
 433  */
 434
 435 static struct files_struct *close_fsp_fd(struct files_struct *fsp,
 436                                          void *private_data)
 437 {
 438         if ((fsp->fh != NULL) && (fsp->fh->fd != -1)) {
 439                 close(fsp->fh->fd);
 440                 fsp->fh->fd = -1;
 441         }
 442         return NULL;
 443 }
 444
 445 static NTSTATUS create_aio_child(struct aio_child_list *children,
 446                                  size_t map_size,
 447                                  struct aio_child **presult)
 448 {
 449         struct aio_child *result;
 450         int fdpair[2];
 451         NTSTATUS status;
 452
 453         fdpair[0] = fdpair[1] = -1;
 454
 455         result = TALLOC_ZERO_P(children, struct aio_child);
 456         NT_STATUS_HAVE_NO_MEMORY(result);
 457
 458         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
 459                 status = map_nt_error_from_unix(errno);
 460                 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
 461                 goto fail;
 462         }
 463
 464         DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
 465
 466         result->map = mmap_area_init(result, map_size);
 467         if (result->map == NULL) {
 468                 status = map_nt_error_from_unix(errno);
 469                 DEBUG(0, ("Could not create mmap area\n"));
 470                 goto fail;
 471         }
 472
 473         result->pid = sys_fork();
 474         if (result->pid == -1) {
 475                 status = map_nt_error_from_unix(errno);
 476                 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
 477                 goto fail;
 478         }
 479
 480         if (result->pid == 0) {
 481                 close(fdpair[0]);
 482                 result->sockfd = fdpair[1];
 483                 files_forall(close_fsp_fd, NULL);
 484                 aio_child_loop(result->sockfd, result->map);
 485         }
 486
 487         DEBUG(10, ("Child %d created\n", result->pid));
 488
 489         result->sockfd = fdpair[0];
 490         close(fdpair[1]);
 491
 492         result->sock_event = event_add_fd(smbd_event_context(), result,
 493                                           result->sockfd, EVENT_FD_READ,
 494                                           handle_aio_completion,
 495                                           result);
 496         if (result->sock_event == NULL) {
 497                 status = NT_STATUS_NO_MEMORY;
 498                 DEBUG(0, ("event_add_fd failed\n"));
 499                 goto fail;
 500         }
 501
 502         result->list = children;
 503         DLIST_ADD(children->children, result);
 504
 505         talloc_set_destructor(result, aio_child_destructor);
 506
 507         *presult = result;
 508
 509         return NT_STATUS_OK;
 510
 511  fail:
 512         if (fdpair[0] != -1) close(fdpair[0]);
 513         if (fdpair[1] != -1) close(fdpair[1]);
 514         TALLOC_FREE(result);
 515
 516         return status;
 517 }
 518
 519 static NTSTATUS get_idle_child(struct vfs_handle_struct *handle,
 520                                struct aio_child **pchild)
 521 {
 522         struct aio_child_list *children;
 523         struct aio_child *child;
 524         NTSTATUS status;
 525
 526         children = init_aio_children(handle);
 527         if (children == NULL) {
 528                 return NT_STATUS_NO_MEMORY;
 529         }
 530
 531         for (child = children->children; child != NULL; child = child->next) {
 532                 if (child->aiocb == NULL) {
 533                         /* idle */
 534                         break;
 535                 }
 536         }
 537
 538         if (child == NULL) {
 539                 DEBUG(10, ("no idle child found, creating new one\n"));
 540
 541                 status = create_aio_child(children, 128*1024, &child);
 542                 if (!NT_STATUS_IS_OK(status)) {
 543                         DEBUG(10, ("create_aio_child failed: %s\n",
 544                                    nt_errstr(status)));
 545                         return status;
 546                 }
 547         }
 548
 549         child->dont_delete = true;
 550
 551         *pchild = child;
 552         return NT_STATUS_OK;
 553 }
 554
 555 static int aio_fork_read(struct vfs_handle_struct *handle,
 556                          struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb)
 557 {
 558         struct aio_child *child;
 559         struct rw_cmd cmd;
 560         ssize_t ret;
 561         NTSTATUS status;
 562
 563         if (aiocb->aio_nbytes > 128*1024) {
 564                 /* TODO: support variable buffers */
 565                 errno = EINVAL;
 566                 return -1;
 567         }
 568
 569         status = get_idle_child(handle, &child);
 570         if (!NT_STATUS_IS_OK(status)) {
 571                 DEBUG(10, ("Could not get an idle child\n"));
 572                 return -1;
 573         }
 574
 575         child->read_cmd = true;
 576         child->aiocb = aiocb;
 577         child->retval.ret_errno = EINPROGRESS;
 578
 579         ZERO_STRUCT(cmd);
 580         cmd.n = aiocb->aio_nbytes;
 581         cmd.offset = aiocb->aio_offset;
 582         cmd.read_cmd = child->read_cmd;
 583
 584         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 585                    (int)child->pid));
 586
 587         ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd);
 588         if (ret == -1) {
 589                 DEBUG(10, ("write_fd failed: %s\n", strerror(errno)));
 590                 return -1;
 591         }
 592
 593         return 0;
 594 }
 595
 596 static int aio_fork_write(struct vfs_handle_struct *handle,
 597                           struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb)
 598 {
 599         struct aio_child *child;
 600         struct rw_cmd cmd;
 601         ssize_t ret;
 602         NTSTATUS status;
 603
 604         if (aiocb->aio_nbytes > 128*1024) {
 605                 /* TODO: support variable buffers */
 606                 errno = EINVAL;
 607                 return -1;
 608         }
 609
 610         status = get_idle_child(handle, &child);
 611         if (!NT_STATUS_IS_OK(status)) {
 612                 DEBUG(10, ("Could not get an idle child\n"));
 613                 return -1;
 614         }
 615
 616         child->read_cmd = false;
 617         child->aiocb = aiocb;
 618         child->retval.ret_errno = EINPROGRESS;
 619
 620         memcpy((void *)child->map->ptr, (void *)aiocb->aio_buf,
 621                aiocb->aio_nbytes);
 622
 623         ZERO_STRUCT(cmd);
 624         cmd.n = aiocb->aio_nbytes;
 625         cmd.offset = aiocb->aio_offset;
 626         cmd.read_cmd = child->read_cmd;
 627
 628         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 629                    (int)child->pid));
 630
 631         ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd);
 632         if (ret == -1) {
 633                 DEBUG(10, ("write_fd failed: %s\n", strerror(errno)));
 634                 return -1;
 635         }
 636
 637         return 0;
 638 }
 639
 640 static struct aio_child *aio_fork_find_child(struct vfs_handle_struct *handle,
 641                                              SMB_STRUCT_AIOCB *aiocb)
 642 {
 643         struct aio_child_list *children;
 644         struct aio_child *child;
 645
 646         children = init_aio_children(handle);
 647         if (children == NULL) {
 648                 return NULL;
 649         }
 650
 651         for (child = children->children; child != NULL; child = child->next) {
 652                 if (child->aiocb == aiocb) {
 653                         return child;
 654                 }
 655         }
 656
 657         return NULL;
 658 }
 659
 660 static ssize_t aio_fork_return_fn(struct vfs_handle_struct *handle,
 661                                   struct files_struct *fsp,
 662                                   SMB_STRUCT_AIOCB *aiocb)
 663 {
 664         struct aio_child *child = aio_fork_find_child(handle, aiocb);
 665
 666         if (child == NULL) {
 667                 errno = EINVAL;
 668                 DEBUG(0, ("returning EINVAL\n"));
 669                 return -1;
 670         }
 671
 672         child->aiocb = NULL;
 673
 674         if (child->retval.size == -1) {
 675                 errno = child->retval.ret_errno;
 676         }
 677
 678         return child->retval.size;
 679 }
 680
 681 static int aio_fork_cancel(struct vfs_handle_struct *handle,
 682                            struct files_struct *fsp,
 683                            SMB_STRUCT_AIOCB *aiocb)
 684 {
 685         struct aio_child_list *children;
 686         struct aio_child *child;
 687
 688         children = init_aio_children(handle);
 689         if (children == NULL) {
 690                 errno = EINVAL;
 691                 return -1;
 692         }
 693
 694         for (child = children->children; child != NULL; child = child->next) {
 695                 if (child->aiocb == NULL) {
 696                         continue;
 697                 }
 698                 if (child->aiocb->aio_fildes != fsp->fh->fd) {
 699                         continue;
 700                 }
 701                 if ((aiocb != NULL) && (child->aiocb != aiocb)) {
 702                         continue;
 703                 }
 704
 705                 /*
 706                  * We let the child do its job, but we discard the result when
 707                  * it's finished.
 708                  */
 709
 710                 child->cancelled = true;
 711         }
 712
 713         return AIO_CANCELED;
 714 }
 715
 716 static int aio_fork_error_fn(struct vfs_handle_struct *handle,
 717                              struct files_struct *fsp,
 718                              SMB_STRUCT_AIOCB *aiocb)
 719 {
 720         struct aio_child *child = aio_fork_find_child(handle, aiocb);
 721
 722         if (child == NULL) {
 723                 errno = EINVAL;
 724                 return -1;
 725         }
 726
 727         return child->retval.ret_errno;
 728 }
 729
 730 static struct vfs_fn_pointers vfs_aio_fork_fns = {
 731         .aio_read = aio_fork_read,
 732         .aio_write = aio_fork_write,
 733         .aio_return_fn = aio_fork_return_fn,
 734         .aio_cancel = aio_fork_cancel,
 735         .aio_error_fn = aio_fork_error_fn,
 736 };
 737
 738 NTSTATUS vfs_aio_fork_init(void);
 739 NTSTATUS vfs_aio_fork_init(void)
 740 {
 741         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 742                                 "aio_fork", &vfs_aio_fork_fns);
 743 }