root/source3/modules/vfs_aio_fork.c

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. mmap_area_destructor
  2. mmap_area_init
  3. free_aio_children
  4. read_fd
  5. write_fd
  6. aio_child_cleanup
  7. init_aio_children
  8. aio_child_loop
  9. handle_aio_completion
  10. aio_child_destructor
  11. close_fsp_fd
  12. create_aio_child
  13. get_idle_child
  14. aio_fork_read
  15. aio_fork_write
  16. aio_fork_find_child
  17. aio_fork_return_fn
  18. aio_fork_cancel
  19. aio_fork_error_fn
  20. vfs_aio_fork_init

   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)
     /* [<][>][^][v][top][bottom][index][help] */
  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)
     /* [<][>][^][v][top][bottom][index][help] */
  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)
     /* [<][>][^][v][top][bottom][index][help] */
 104 {
 105         TALLOC_FREE(*p);
 106 }
 107 
 108 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
     /* [<][>][^][v][top][bottom][index][help] */
 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 = 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)
     /* [<][>][^][v][top][bottom][index][help] */
 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 = 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,
     /* [<][>][^][v][top][bottom][index][help] */
 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)
     /* [<][>][^][v][top][bottom][index][help] */
 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)
     /* [<][>][^][v][top][bottom][index][help] */
 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                 /*
 361                  * Close the fd before telling our parent we're done. The
 362                  * parent might close and re-open the file very quickly, and
 363                  * with system-level share modes (GPFS) we would get an
 364                  * unjustified SHARING_VIOLATION.
 365                  */
 366                 close(fd);
 367 
 368                 ret = write_data(sockfd, (char *)&ret_struct,
 369                                  sizeof(ret_struct));
 370                 if (ret != sizeof(ret_struct)) {
 371                         DEBUG(10, ("could not write ret_struct: %s\n",
 372                                    strerror(errno)));
 373                         exit(2);
 374                 }
 375         }
 376 }
 377 
 378 static void handle_aio_completion(struct event_context *event_ctx,
     /* [<][>][^][v][top][bottom][index][help] */
 379                                   struct fd_event *event, uint16 flags,
 380                                   void *p)
 381 {
 382         struct aio_child *child = (struct aio_child *)p;
 383         uint16 mid;
 384 
 385         DEBUG(10, ("handle_aio_completion called with flags=%d\n", flags));
 386 
 387         if ((flags & EVENT_FD_READ) == 0) {
 388                 return;
 389         }
 390 
 391         if (!NT_STATUS_IS_OK(read_data(child->sockfd,
 392                                        (char *)&child->retval,
 393                                        sizeof(child->retval)))) {
 394                 DEBUG(0, ("aio child %d died\n", (int)child->pid));
 395                 child->retval.size = -1;
 396                 child->retval.ret_errno = EIO;
 397         }
 398 
 399         if (child->cancelled) {
 400                 child->aiocb = NULL;
 401                 child->cancelled = false;
 402                 return;
 403         }
 404 
 405         if (child->read_cmd && (child->retval.size > 0)) {
 406                 SMB_ASSERT(child->retval.size <= child->aiocb->aio_nbytes);
 407                 memcpy((void *)child->aiocb->aio_buf, (void *)child->map->ptr,
 408                        child->retval.size);
 409         }
 410 
 411         mid = child->aiocb->aio_sigevent.sigev_value.sival_int;
 412 
 413         DEBUG(10, ("mid %d finished\n", (int)mid));
 414 
 415         smbd_aio_complete_mid(mid);
 416 }
 417 
 418 static int aio_child_destructor(struct aio_child *child)
     /* [<][>][^][v][top][bottom][index][help] */
 419 {
 420         SMB_ASSERT((child->aiocb == NULL) || child->cancelled);
 421         close(child->sockfd);
 422         DLIST_REMOVE(child->list->children, child);
 423         return 0;
 424 }
 425 
 426 /*
 427  * We have to close all fd's in open files, we might incorrectly hold a system
 428  * level share mode on a file.
 429  */
 430 
 431 static struct files_struct *close_fsp_fd(struct files_struct *fsp,
     /* [<][>][^][v][top][bottom][index][help] */
 432                                          void *private_data)
 433 {
 434         if ((fsp->fh != NULL) && (fsp->fh->fd != -1)) {
 435                 close(fsp->fh->fd);
 436                 fsp->fh->fd = -1;
 437         }
 438         return NULL;
 439 }
 440 
 441 static NTSTATUS create_aio_child(struct aio_child_list *children,
     /* [<][>][^][v][top][bottom][index][help] */
 442                                  size_t map_size,
 443                                  struct aio_child **presult)
 444 {
 445         struct aio_child *result;
 446         int fdpair[2];
 447         NTSTATUS status;
 448 
 449         fdpair[0] = fdpair[1] = -1;
 450 
 451         result = TALLOC_ZERO_P(children, struct aio_child);
 452         NT_STATUS_HAVE_NO_MEMORY(result);
 453 
 454         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
 455                 status = map_nt_error_from_unix(errno);
 456                 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
 457                 goto fail;
 458         }
 459 
 460         DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
 461 
 462         result->map = mmap_area_init(result, map_size);
 463         if (result->map == NULL) {
 464                 status = map_nt_error_from_unix(errno);
 465                 DEBUG(0, ("Could not create mmap area\n"));
 466                 goto fail;
 467         }
 468 
 469         result->pid = sys_fork();
 470         if (result->pid == -1) {
 471                 status = map_nt_error_from_unix(errno);
 472                 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
 473                 goto fail;
 474         }
 475 
 476         if (result->pid == 0) {
 477                 close(fdpair[0]);
 478                 result->sockfd = fdpair[1];
 479                 file_walk_table(close_fsp_fd, NULL);
 480                 aio_child_loop(result->sockfd, result->map);
 481         }
 482 
 483         DEBUG(10, ("Child %d created\n", result->pid));
 484 
 485         result->sockfd = fdpair[0];
 486         close(fdpair[1]);
 487 
 488         result->sock_event = event_add_fd(smbd_event_context(), result,
 489                                           result->sockfd, EVENT_FD_READ,
 490                                           handle_aio_completion,
 491                                           result);
 492         if (result->sock_event == NULL) {
 493                 status = NT_STATUS_NO_MEMORY;
 494                 DEBUG(0, ("event_add_fd failed\n"));
 495                 goto fail;
 496         }
 497 
 498         result->list = children;
 499         DLIST_ADD(children->children, result);
 500 
 501         talloc_set_destructor(result, aio_child_destructor);
 502 
 503         *presult = result;
 504 
 505         return NT_STATUS_OK;
 506 
 507  fail:
 508         if (fdpair[0] != -1) close(fdpair[0]);
 509         if (fdpair[1] != -1) close(fdpair[1]);
 510         TALLOC_FREE(result);
 511 
 512         return status;
 513 }
 514 
 515 static NTSTATUS get_idle_child(struct vfs_handle_struct *handle,
     /* [<][>][^][v][top][bottom][index][help] */
 516                                struct aio_child **pchild)
 517 {
 518         struct aio_child_list *children;
 519         struct aio_child *child;
 520         NTSTATUS status;
 521 
 522         children = init_aio_children(handle);
 523         if (children == NULL) {
 524                 return NT_STATUS_NO_MEMORY;
 525         }
 526 
 527         for (child = children->children; child != NULL; child = child->next) {
 528                 if (child->aiocb == NULL) {
 529                         /* idle */
 530                         break;
 531                 }
 532         }
 533 
 534         if (child == NULL) {
 535                 DEBUG(10, ("no idle child found, creating new one\n"));
 536 
 537                 status = create_aio_child(children, 128*1024, &child);
 538                 if (!NT_STATUS_IS_OK(status)) {
 539                         DEBUG(10, ("create_aio_child failed: %s\n",
 540                                    nt_errstr(status)));
 541                         return status;
 542                 }
 543         }
 544 
 545         child->dont_delete = true;
 546 
 547         *pchild = child;
 548         return NT_STATUS_OK;
 549 }
 550 
 551 static int aio_fork_read(struct vfs_handle_struct *handle,
     /* [<][>][^][v][top][bottom][index][help] */
 552                          struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb)
 553 {
 554         struct aio_child *child;
 555         struct rw_cmd cmd;
 556         ssize_t ret;
 557         NTSTATUS status;
 558 
 559         if (aiocb->aio_nbytes > 128*1024) {
 560                 /* TODO: support variable buffers */
 561                 errno = EINVAL;
 562                 return -1;
 563         }
 564 
 565         status = get_idle_child(handle, &child);
 566         if (!NT_STATUS_IS_OK(status)) {
 567                 DEBUG(10, ("Could not get an idle child\n"));
 568                 return -1;
 569         }
 570 
 571         child->read_cmd = true;
 572         child->aiocb = aiocb;
 573         child->retval.ret_errno = EINPROGRESS;
 574 
 575         ZERO_STRUCT(cmd);
 576         cmd.n = aiocb->aio_nbytes;
 577         cmd.offset = aiocb->aio_offset;
 578         cmd.read_cmd = child->read_cmd;
 579 
 580         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 581                    (int)child->pid));
 582 
 583         ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd);
 584         if (ret == -1) {
 585                 DEBUG(10, ("write_fd failed: %s\n", strerror(errno)));
 586                 return -1;
 587         }
 588 
 589         return 0;
 590 }
 591 
 592 static int aio_fork_write(struct vfs_handle_struct *handle,
     /* [<][>][^][v][top][bottom][index][help] */
 593                           struct files_struct *fsp, SMB_STRUCT_AIOCB *aiocb)
 594 {
 595         struct aio_child *child;
 596         struct rw_cmd cmd;
 597         ssize_t ret;
 598         NTSTATUS status;
 599 
 600         if (aiocb->aio_nbytes > 128*1024) {
 601                 /* TODO: support variable buffers */
 602                 errno = EINVAL;
 603                 return -1;
 604         }
 605 
 606         status = get_idle_child(handle, &child);
 607         if (!NT_STATUS_IS_OK(status)) {
 608                 DEBUG(10, ("Could not get an idle child\n"));
 609                 return -1;
 610         }
 611 
 612         child->read_cmd = false;
 613         child->aiocb = aiocb;
 614         child->retval.ret_errno = EINPROGRESS;
 615 
 616         memcpy((void *)child->map->ptr, (void *)aiocb->aio_buf,
 617                aiocb->aio_nbytes);
 618 
 619         ZERO_STRUCT(cmd);
 620         cmd.n = aiocb->aio_nbytes;
 621         cmd.offset = aiocb->aio_offset;
 622         cmd.read_cmd = child->read_cmd;
 623 
 624         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 625                    (int)child->pid));
 626 
 627         ret = write_fd(child->sockfd, &cmd, sizeof(cmd), fsp->fh->fd);
 628         if (ret == -1) {
 629                 DEBUG(10, ("write_fd failed: %s\n", strerror(errno)));
 630                 return -1;
 631         }
 632 
 633         return 0;
 634 }
 635 
 636 static struct aio_child *aio_fork_find_child(struct vfs_handle_struct *handle,
     /* [<][>][^][v][top][bottom][index][help] */
 637                                              SMB_STRUCT_AIOCB *aiocb)
 638 {
 639         struct aio_child_list *children;
 640         struct aio_child *child;
 641 
 642         children = init_aio_children(handle);
 643         if (children == NULL) {
 644                 return NULL;
 645         }
 646 
 647         for (child = children->children; child != NULL; child = child->next) {
 648                 if (child->aiocb == aiocb) {
 649                         return child;
 650                 }
 651         }
 652 
 653         return NULL;
 654 }
 655 
 656 static ssize_t aio_fork_return_fn(struct vfs_handle_struct *handle,
     /* [<][>][^][v][top][bottom][index][help] */
 657                                   struct files_struct *fsp,
 658                                   SMB_STRUCT_AIOCB *aiocb)
 659 {
 660         struct aio_child *child = aio_fork_find_child(handle, aiocb);
 661 
 662         if (child == NULL) {
 663                 errno = EINVAL;
 664                 DEBUG(0, ("returning EINVAL\n"));
 665                 return -1;
 666         }
 667 
 668         child->aiocb = NULL;
 669 
 670         if (child->retval.size == -1) {
 671                 errno = child->retval.ret_errno;
 672         }
 673 
 674         return child->retval.size;
 675 }
 676 
 677 static int aio_fork_cancel(struct vfs_handle_struct *handle,
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 678                            struct files_struct *fsp,
 679                            SMB_STRUCT_AIOCB *aiocb)
 680 {
 681         struct aio_child_list *children;
 682         struct aio_child *child;
 683 
 684         children = init_aio_children(handle);
 685         if (children == NULL) {
 686                 errno = EINVAL;
 687                 return -1;
 688         }
 689 
 690         for (child = children->children; child != NULL; child = child->next) {
 691                 if (child->aiocb == NULL) {
 692                         continue;
 693                 }
 694                 if (child->aiocb->aio_fildes != fsp->fh->fd) {
 695                         continue;
 696                 }
 697                 if ((aiocb != NULL) && (child->aiocb != aiocb)) {
 698                         continue;
 699                 }
 700 
 701                 /*
 702                  * We let the child do its job, but we discard the result when
 703                  * it's finished.
 704                  */
 705 
 706                 child->cancelled = true;
 707         }
 708 
 709         return AIO_CANCELED;
 710 }
 711 
 712 static int aio_fork_error_fn(struct vfs_handle_struct *handle,
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 713                              struct files_struct *fsp,
 714                              SMB_STRUCT_AIOCB *aiocb)
 715 {
 716         struct aio_child *child = aio_fork_find_child(handle, aiocb);
 717 
 718         if (child == NULL) {
 719                 errno = EINVAL;
 720                 return -1;
 721         }
 722 
 723         return child->retval.ret_errno;
 724 }
 725 
 726 /* VFS operations structure */
 727 
 728 static vfs_op_tuple aio_fork_ops[] = {
 729         {SMB_VFS_OP(aio_fork_read),     SMB_VFS_OP_AIO_READ,
 730          SMB_VFS_LAYER_TRANSPARENT},
 731         {SMB_VFS_OP(aio_fork_write),    SMB_VFS_OP_AIO_WRITE,
 732          SMB_VFS_LAYER_TRANSPARENT},
 733         {SMB_VFS_OP(aio_fork_return_fn), SMB_VFS_OP_AIO_RETURN,
 734          SMB_VFS_LAYER_TRANSPARENT},
 735         {SMB_VFS_OP(aio_fork_cancel),   SMB_VFS_OP_AIO_CANCEL,
 736          SMB_VFS_LAYER_TRANSPARENT},
 737         {SMB_VFS_OP(aio_fork_error_fn), SMB_VFS_OP_AIO_ERROR,
 738          SMB_VFS_LAYER_TRANSPARENT},
 739         {SMB_VFS_OP(NULL),              SMB_VFS_OP_NOOP,
 740          SMB_VFS_LAYER_NOOP}
 741 };
 742 
 743 NTSTATUS vfs_aio_fork_init(void);
 744 NTSTATUS vfs_aio_fork_init(void)
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 745 {
 746         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 747                                 "aio_fork", aio_fork_ops);
 748 }

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