source3/modules/vfs_aio_fork.c

   1 /*
   2  * Simulate the Posix AIO using mmap/fork
   3  *
   4  * Copyright (C) Volker Lendecke 2008
   5  * Copyright (C) Jeremy Allison 2010
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include "includes.h"
  23 #include "system/filesys.h"
  24 #include "system/shmem.h"
  25 #include "smbd/smbd.h"
  26 #include "smbd/globals.h"
  27 #include "lib/async_req/async_sock.h"
  28 #include "lib/util/tevent_unix.h"
  29 #include "lib/util/sys_rw.h"
  30 #include "lib/util/sys_rw_data.h"
  31 #include "lib/util/msghdr.h"
  32 #include "smbprofile.h"
  33
  34 #if !defined(HAVE_STRUCT_MSGHDR_MSG_CONTROL) && !defined(HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS)
  35 # error Can not pass file descriptors
  36 #endif
  37
  38 #undef recvmsg
  39
  40 #ifndef MAP_FILE
  41 #define MAP_FILE 0
  42 #endif
  43
  44 struct aio_child_list;
  45
  46 struct aio_fork_config {
  47         bool erratic_testing_mode;
  48         struct aio_child_list *children;
  49 };
  50
  51 struct mmap_area {
  52         size_t size;
  53         void *ptr;
  54 };
  55
  56 static int mmap_area_destructor(struct mmap_area *area)
  57 {
  58         munmap(discard_const(area->ptr), area->size);
  59         return 0;
  60 }
  61
  62 static struct mmap_area *mmap_area_init(TALLOC_CTX *mem_ctx, size_t size)
  63 {
  64         struct mmap_area *result;
  65         int fd;
  66
  67         result = talloc(mem_ctx, struct mmap_area);
  68         if (result == NULL) {
  69                 DEBUG(0, ("talloc failed\n"));
  70                 goto fail;
  71         }
  72
  73         fd = open("/dev/zero", O_RDWR);
  74         if (fd == -1) {
  75                 DEBUG(3, ("open(\"/dev/zero\") failed: %s\n",
  76                           strerror(errno)));
  77                 goto fail;
  78         }
  79
  80         result->ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
  81                            MAP_SHARED|MAP_FILE, fd, 0);
  82         close(fd);
  83         if (result->ptr == MAP_FAILED) {
  84                 DEBUG(1, ("mmap failed: %s\n", strerror(errno)));
  85                 goto fail;
  86         }
  87
  88         result->size = size;
  89         talloc_set_destructor(result, mmap_area_destructor);
  90
  91         return result;
  92
  93 fail:
  94         TALLOC_FREE(result);
  95         return NULL;
  96 }
  97
  98 enum cmd_type {
  99         READ_CMD,
 100         WRITE_CMD,
 101         FSYNC_CMD
 102 };
 103
 104 static const char *cmd_type_str(enum cmd_type cmd)
 105 {
 106         const char *result;
 107
 108         switch (cmd) {
 109         case READ_CMD:
 110                 result = "READ";
 111                 break;
 112         case WRITE_CMD:
 113                 result = "WRITE";
 114                 break;
 115         case FSYNC_CMD:
 116                 result = "FSYNC";
 117                 break;
 118         default:
 119                 result = "<UNKNOWN>";
 120                 break;
 121         }
 122         return result;
 123 }
 124
 125 struct rw_cmd {
 126         size_t n;
 127         off_t offset;
 128         enum cmd_type cmd;
 129         bool erratic_testing_mode;
 130 };
 131
 132 struct rw_ret {
 133         ssize_t size;
 134         int ret_errno;
 135         uint64_t duration;
 136 };
 137
 138 struct aio_child_list;
 139
 140 struct aio_child {
 141         struct aio_child *prev, *next;
 142         struct aio_child_list *list;
 143         pid_t pid;
 144         int sockfd;
 145         struct mmap_area *map;
 146         bool dont_delete;       /* Marked as in use since last cleanup */
 147         bool busy;
 148 };
 149
 150 struct aio_child_list {
 151         struct aio_child *children;
 152         struct tevent_timer *cleanup_event;
 153 };
 154
 155 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
 156 {
 157         struct iovec iov[1];
 158         struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1 };
 159         ssize_t n;
 160         size_t bufsize = msghdr_prep_recv_fds(NULL, NULL, 0, 1);
 161         uint8_t buf[bufsize];
 162
 163         msghdr_prep_recv_fds(&msg, buf, bufsize, 1);
 164
 165         iov[0].iov_base = (void *)ptr;
 166         iov[0].iov_len = nbytes;
 167
 168         do {
 169                 n = recvmsg(fd, &msg, 0);
 170         } while ((n == -1) && (errno == EINTR));
 171
 172         if (n <= 0) {
 173                 return n;
 174         }
 175
 176         {
 177                 size_t num_fds = msghdr_extract_fds(&msg, NULL, 0);
 178                 int fds[num_fds];
 179
 180                 msghdr_extract_fds(&msg, fds, num_fds);
 181
 182                 if (num_fds != 1) {
 183                         size_t i;
 184
 185                         for (i=0; i<num_fds; i++) {
 186                                 close(fds[i]);
 187                         }
 188
 189                         *recvfd = -1;
 190                         return n;
 191                 }
 192
 193                 *recvfd = fds[0];
 194         }
 195
 196         return(n);
 197 }
 198
 199 static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd)
 200 {
 201         struct msghdr msg = {0};
 202         size_t bufsize = msghdr_prep_fds(NULL, NULL, 0, &sendfd, 1);
 203         uint8_t buf[bufsize];
 204         struct iovec iov;
 205         ssize_t sent;
 206
 207         msghdr_prep_fds(&msg, buf, bufsize, &sendfd, 1);
 208
 209         iov.iov_base = (void *)ptr;
 210         iov.iov_len = nbytes;
 211         msg.msg_iov = &iov;
 212         msg.msg_iovlen = 1;
 213
 214         do {
 215                 sent = sendmsg(fd, &msg, 0);
 216         } while ((sent == -1) && (errno == EINTR));
 217
 218         return sent;
 219 }
 220
 221 static void aio_child_cleanup(struct tevent_context *event_ctx,
 222                               struct tevent_timer *te,
 223                               struct timeval now,
 224                               void *private_data)
 225 {
 226         struct aio_child_list *list = talloc_get_type_abort(
 227                 private_data, struct aio_child_list);
 228         struct aio_child *child, *next;
 229
 230         TALLOC_FREE(list->cleanup_event);
 231
 232         for (child = list->children; child != NULL; child = next) {
 233                 next = child->next;
 234
 235                 if (child->busy) {
 236                         DEBUG(10, ("child %d currently active\n",
 237                                    (int)child->pid));
 238                         continue;
 239                 }
 240
 241                 if (child->dont_delete) {
 242                         DEBUG(10, ("Child %d was active since last cleanup\n",
 243                                    (int)child->pid));
 244                         child->dont_delete = false;
 245                         continue;
 246                 }
 247
 248                 DEBUG(10, ("Child %d idle for more than 30 seconds, "
 249                            "deleting\n", (int)child->pid));
 250
 251                 TALLOC_FREE(child);
 252                 child = next;
 253         }
 254
 255         if (list->children != NULL) {
 256                 /*
 257                  * Re-schedule the next cleanup round
 258                  */
 259                 list->cleanup_event = tevent_add_timer(global_event_context(), list,
 260                                                       timeval_add(&now, 30, 0),
 261                                                       aio_child_cleanup, list);
 262
 263         }
 264 }
 265
 266 static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle)
 267 {
 268         struct aio_fork_config *config;
 269         struct aio_child_list *children;
 270
 271         SMB_VFS_HANDLE_GET_DATA(handle, config, struct aio_fork_config,
 272                                 return NULL);
 273
 274         if (config->children == NULL) {
 275                 config->children = talloc_zero(config, struct aio_child_list);
 276                 if (config->children == NULL) {
 277                         return NULL;
 278                 }
 279         }
 280         children = config->children;
 281
 282         /*
 283          * Regardless of whether the child_list had been around or not, make
 284          * sure that we have a cleanup timed event. This timed event will
 285          * delete itself when it finds that no children are around anymore.
 286          */
 287
 288         if (children->cleanup_event == NULL) {
 289                 children->cleanup_event =
 290                         tevent_add_timer(global_event_context(), children,
 291                                          timeval_current_ofs(30, 0),
 292                                          aio_child_cleanup, children);
 293                 if (children->cleanup_event == NULL) {
 294                         TALLOC_FREE(config->children);
 295                         return NULL;
 296                 }
 297         }
 298
 299         return children;
 300 }
 301
 302 static void aio_child_loop(int sockfd, struct mmap_area *map)
 303 {
 304         while (true) {
 305                 int fd = -1;
 306                 ssize_t ret;
 307                 struct rw_cmd cmd_struct;
 308                 struct rw_ret ret_struct;
 309                 struct timespec start, end;
 310
 311                 ret = read_fd(sockfd, &cmd_struct, sizeof(cmd_struct), &fd);
 312                 if (ret != sizeof(cmd_struct)) {
 313                         DEBUG(10, ("read_fd returned %d: %s\n", (int)ret,
 314                                    strerror(errno)));
 315                         exit(1);
 316                 }
 317
 318                 DEBUG(10, ("aio_child_loop: %s %d bytes at %d from fd %d\n",
 319                            cmd_type_str(cmd_struct.cmd),
 320                            (int)cmd_struct.n, (int)cmd_struct.offset, fd));
 321
 322                 if (cmd_struct.erratic_testing_mode) {
 323                         /*
 324                          * For developer testing, we want erratic behaviour for
 325                          * async I/O times
 326                          */
 327                         uint8_t randval;
 328                         unsigned msecs;
 329                         /*
 330                          * use generate_random_buffer, we just forked from a
 331                          * common parent state
 332                          */
 333                         generate_random_buffer(&randval, sizeof(randval));
 334                         msecs = (randval%20)+1;
 335                         DEBUG(10, ("delaying for %u msecs\n", msecs));
 336                         smb_msleep(msecs);
 337                 }
 338
 339                 ZERO_STRUCT(ret_struct);
 340
 341                 PROFILE_TIMESTAMP(&start);
 342
 343                 switch (cmd_struct.cmd) {
 344                 case READ_CMD:
 345                         ret_struct.size = sys_pread(
 346                                 fd, discard_const(map->ptr), cmd_struct.n,
 347                                 cmd_struct.offset);
 348 #if 0
 349 /* This breaks "make test" when run with aio_fork module. */
 350 #ifdef DEVELOPER
 351                         ret_struct.size = MAX(1, ret_struct.size * 0.9);
 352 #endif
 353 #endif
 354                         break;
 355                 case WRITE_CMD:
 356                         ret_struct.size = sys_pwrite(
 357                                 fd, discard_const(map->ptr), cmd_struct.n,
 358                                 cmd_struct.offset);
 359                         break;
 360                 case FSYNC_CMD:
 361                         ret_struct.size = fsync(fd);
 362                         break;
 363                 default:
 364                         ret_struct.size = -1;
 365                         errno = EINVAL;
 366                 }
 367
 368                 PROFILE_TIMESTAMP(&end);
 369                 ret_struct.duration = nsec_time_diff(&end, &start);
 370                 DEBUG(10, ("aio_child_loop: syscall returned %d\n",
 371                            (int)ret_struct.size));
 372
 373                 if (ret_struct.size == -1) {
 374                         ret_struct.ret_errno = errno;
 375                 }
 376
 377                 /*
 378                  * Close the fd before telling our parent we're done. The
 379                  * parent might close and re-open the file very quickly, and
 380                  * with system-level share modes (GPFS) we would get an
 381                  * unjustified SHARING_VIOLATION.
 382                  */
 383                 close(fd);
 384
 385                 ret = write_data(sockfd, (char *)&ret_struct,
 386                                  sizeof(ret_struct));
 387                 if (ret != sizeof(ret_struct)) {
 388                         DEBUG(10, ("could not write ret_struct: %s\n",
 389                                    strerror(errno)));
 390                         exit(2);
 391                 }
 392         }
 393 }
 394
 395 static int aio_child_destructor(struct aio_child *child)
 396 {
 397         char c=0;
 398
 399         SMB_ASSERT(!child->busy);
 400
 401         DEBUG(10, ("aio_child_destructor: removing child %d on fd %d\n",
 402                    (int)child->pid, child->sockfd));
 403
 404         /*
 405          * closing the sockfd makes the child not return from recvmsg() on RHEL
 406          * 5.5 so instead force the child to exit by writing bad data to it
 407          */
 408         sys_write_v(child->sockfd, &c, sizeof(c));
 409         close(child->sockfd);
 410         DLIST_REMOVE(child->list->children, child);
 411         return 0;
 412 }
 413
 414 /*
 415  * We have to close all fd's in open files, we might incorrectly hold a system
 416  * level share mode on a file.
 417  */
 418
 419 static struct files_struct *close_fsp_fd(struct files_struct *fsp,
 420                                          void *private_data)
 421 {
 422         if ((fsp->fh != NULL) && (fsp->fh->fd != -1)) {
 423                 close(fsp->fh->fd);
 424                 fsp->fh->fd = -1;
 425         }
 426         return NULL;
 427 }
 428
 429 static int create_aio_child(struct smbd_server_connection *sconn,
 430                             struct aio_child_list *children,
 431                             size_t map_size,
 432                             struct aio_child **presult)
 433 {
 434         struct aio_child *result;
 435         int fdpair[2];
 436         int ret;
 437
 438         fdpair[0] = fdpair[1] = -1;
 439
 440         result = talloc_zero(children, struct aio_child);
 441         if (result == NULL) {
 442                 return ENOMEM;
 443         }
 444
 445         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
 446                 ret = errno;
 447                 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
 448                 goto fail;
 449         }
 450
 451         DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
 452
 453         result->map = mmap_area_init(result, map_size);
 454         if (result->map == NULL) {
 455                 ret = errno;
 456                 DEBUG(0, ("Could not create mmap area\n"));
 457                 goto fail;
 458         }
 459
 460         result->pid = fork();
 461         if (result->pid == -1) {
 462                 ret = errno;
 463                 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
 464                 goto fail;
 465         }
 466
 467         if (result->pid == 0) {
 468                 close(fdpair[0]);
 469                 result->sockfd = fdpair[1];
 470                 files_forall(sconn, close_fsp_fd, NULL);
 471                 aio_child_loop(result->sockfd, result->map);
 472         }
 473
 474         DEBUG(10, ("Child %d created with sockfd %d\n",
 475                    (int)result->pid, fdpair[0]));
 476
 477         result->sockfd = fdpair[0];
 478         close(fdpair[1]);
 479
 480         result->list = children;
 481         DLIST_ADD(children->children, result);
 482
 483         talloc_set_destructor(result, aio_child_destructor);
 484
 485         *presult = result;
 486
 487         return 0;
 488
 489  fail:
 490         if (fdpair[0] != -1) close(fdpair[0]);
 491         if (fdpair[1] != -1) close(fdpair[1]);
 492         TALLOC_FREE(result);
 493
 494         return ret;
 495 }
 496
 497 static int get_idle_child(struct vfs_handle_struct *handle,
 498                           struct aio_child **pchild)
 499 {
 500         struct aio_child_list *children;
 501         struct aio_child *child;
 502
 503         children = init_aio_children(handle);
 504         if (children == NULL) {
 505                 return ENOMEM;
 506         }
 507
 508         for (child = children->children; child != NULL; child = child->next) {
 509                 if (!child->busy) {
 510                         break;
 511                 }
 512         }
 513
 514         if (child == NULL) {
 515                 int ret;
 516
 517                 DEBUG(10, ("no idle child found, creating new one\n"));
 518
 519                 ret = create_aio_child(handle->conn->sconn, children,
 520                                           128*1024, &child);
 521                 if (ret != 0) {
 522                         DEBUG(10, ("create_aio_child failed: %s\n",
 523                                    strerror(errno)));
 524                         return ret;
 525                 }
 526         }
 527
 528         child->dont_delete = true;
 529         child->busy = true;
 530
 531         *pchild = child;
 532         return 0;
 533 }
 534
 535 struct aio_fork_pread_state {
 536         struct aio_child *child;
 537         size_t n;
 538         void *data;
 539         ssize_t ret;
 540         struct vfs_aio_state vfs_aio_state;
 541 };
 542
 543 static void aio_fork_pread_done(struct tevent_req *subreq);
 544
 545 static struct tevent_req *aio_fork_pread_send(struct vfs_handle_struct *handle,
 546                                               TALLOC_CTX *mem_ctx,
 547                                               struct tevent_context *ev,
 548                                               struct files_struct *fsp,
 549                                               void *data,
 550                                               size_t n, off_t offset)
 551 {
 552         struct tevent_req *req, *subreq;
 553         struct aio_fork_pread_state *state;
 554         struct rw_cmd cmd;
 555         ssize_t written;
 556         int err;
 557         struct aio_fork_config *config;
 558
 559         SMB_VFS_HANDLE_GET_DATA(handle, config,
 560                                 struct aio_fork_config,
 561                                 return NULL);
 562
 563         req = tevent_req_create(mem_ctx, &state, struct aio_fork_pread_state);
 564         if (req == NULL) {
 565                 return NULL;
 566         }
 567         state->n = n;
 568         state->data = data;
 569
 570         if (n > 128*1024) {
 571                 /* TODO: support variable buffers */
 572                 tevent_req_error(req, EINVAL);
 573                 return tevent_req_post(req, ev);
 574         }
 575
 576         err = get_idle_child(handle, &state->child);
 577         if (err != 0) {
 578                 tevent_req_error(req, err);
 579                 return tevent_req_post(req, ev);
 580         }
 581
 582         ZERO_STRUCT(cmd);
 583         cmd.n = n;
 584         cmd.offset = offset;
 585         cmd.cmd = READ_CMD;
 586         cmd.erratic_testing_mode = config->erratic_testing_mode;
 587
 588         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 589                    (int)state->child->pid));
 590
 591         /*
 592          * Not making this async. We're writing into an empty unix
 593          * domain socket. This should never block.
 594          */
 595         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 596                            fsp->fh->fd);
 597         if (written == -1) {
 598                 err = errno;
 599
 600                 TALLOC_FREE(state->child);
 601
 602                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 603                 tevent_req_error(req, err);
 604                 return tevent_req_post(req, ev);
 605         }
 606
 607         subreq = read_packet_send(state, ev, state->child->sockfd,
 608                                   sizeof(struct rw_ret), NULL, NULL);
 609         if (tevent_req_nomem(subreq, req)) {
 610                 TALLOC_FREE(state->child); /* we sent sth down */
 611                 return tevent_req_post(req, ev);
 612         }
 613         tevent_req_set_callback(subreq, aio_fork_pread_done, req);
 614         return req;
 615 }
 616
 617 static void aio_fork_pread_done(struct tevent_req *subreq)
 618 {
 619         struct tevent_req *req = tevent_req_callback_data(
 620                 subreq, struct tevent_req);
 621         struct aio_fork_pread_state *state = tevent_req_data(
 622                 req, struct aio_fork_pread_state);
 623         ssize_t nread;
 624         uint8_t *buf;
 625         int err;
 626         struct rw_ret *retbuf;
 627
 628         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 629         TALLOC_FREE(subreq);
 630         if (nread == -1) {
 631                 TALLOC_FREE(state->child);
 632                 tevent_req_error(req, err);
 633                 return;
 634         }
 635
 636         retbuf = (struct rw_ret *)buf;
 637         state->ret = retbuf->size;
 638         state->vfs_aio_state.error = retbuf->ret_errno;
 639         state->vfs_aio_state.duration = retbuf->duration;
 640
 641         if ((size_t)state->ret > state->n) {
 642                 tevent_req_error(req, EIO);
 643                 state->child->busy = false;
 644                 return;
 645         }
 646         memcpy(state->data, state->child->map->ptr, state->ret);
 647
 648         state->child->busy = false;
 649
 650         tevent_req_done(req);
 651 }
 652
 653 static ssize_t aio_fork_pread_recv(struct tevent_req *req,
 654                                    struct vfs_aio_state *vfs_aio_state)
 655 {
 656         struct aio_fork_pread_state *state = tevent_req_data(
 657                 req, struct aio_fork_pread_state);
 658
 659         if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
 660                 return -1;
 661         }
 662         *vfs_aio_state = state->vfs_aio_state;
 663         return state->ret;
 664 }
 665
 666 struct aio_fork_pwrite_state {
 667         struct aio_child *child;
 668         ssize_t ret;
 669         struct vfs_aio_state vfs_aio_state;
 670 };
 671
 672 static void aio_fork_pwrite_done(struct tevent_req *subreq);
 673
 674 static struct tevent_req *aio_fork_pwrite_send(
 675         struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
 676         struct tevent_context *ev, struct files_struct *fsp,
 677         const void *data, size_t n, off_t offset)
 678 {
 679         struct tevent_req *req, *subreq;
 680         struct aio_fork_pwrite_state *state;
 681         struct rw_cmd cmd;
 682         ssize_t written;
 683         int err;
 684         struct aio_fork_config *config;
 685         SMB_VFS_HANDLE_GET_DATA(handle, config,
 686                                 struct aio_fork_config,
 687                                 return NULL);
 688
 689         req = tevent_req_create(mem_ctx, &state, struct aio_fork_pwrite_state);
 690         if (req == NULL) {
 691                 return NULL;
 692         }
 693
 694         if (n > 128*1024) {
 695                 /* TODO: support variable buffers */
 696                 tevent_req_error(req, EINVAL);
 697                 return tevent_req_post(req, ev);
 698         }
 699
 700         err = get_idle_child(handle, &state->child);
 701         if (err != 0) {
 702                 tevent_req_error(req, err);
 703                 return tevent_req_post(req, ev);
 704         }
 705
 706         memcpy(state->child->map->ptr, data, n);
 707
 708         ZERO_STRUCT(cmd);
 709         cmd.n = n;
 710         cmd.offset = offset;
 711         cmd.cmd = WRITE_CMD;
 712         cmd.erratic_testing_mode = config->erratic_testing_mode;
 713
 714         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 715                    (int)state->child->pid));
 716
 717         /*
 718          * Not making this async. We're writing into an empty unix
 719          * domain socket. This should never block.
 720          */
 721         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 722                            fsp->fh->fd);
 723         if (written == -1) {
 724                 err = errno;
 725
 726                 TALLOC_FREE(state->child);
 727
 728                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 729                 tevent_req_error(req, err);
 730                 return tevent_req_post(req, ev);
 731         }
 732
 733         subreq = read_packet_send(state, ev, state->child->sockfd,
 734                                   sizeof(struct rw_ret), NULL, NULL);
 735         if (tevent_req_nomem(subreq, req)) {
 736                 TALLOC_FREE(state->child); /* we sent sth down */
 737                 return tevent_req_post(req, ev);
 738         }
 739         tevent_req_set_callback(subreq, aio_fork_pwrite_done, req);
 740         return req;
 741 }
 742
 743 static void aio_fork_pwrite_done(struct tevent_req *subreq)
 744 {
 745         struct tevent_req *req = tevent_req_callback_data(
 746                 subreq, struct tevent_req);
 747         struct aio_fork_pwrite_state *state = tevent_req_data(
 748                 req, struct aio_fork_pwrite_state);
 749         ssize_t nread;
 750         uint8_t *buf;
 751         int err;
 752         struct rw_ret *retbuf;
 753
 754         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 755         TALLOC_FREE(subreq);
 756         if (nread == -1) {
 757                 TALLOC_FREE(state->child);
 758                 tevent_req_error(req, err);
 759                 return;
 760         }
 761
 762         state->child->busy = false;
 763
 764         retbuf = (struct rw_ret *)buf;
 765         state->ret = retbuf->size;
 766         state->vfs_aio_state.error = retbuf->ret_errno;
 767         state->vfs_aio_state.duration = retbuf->duration;
 768         tevent_req_done(req);
 769 }
 770
 771 static ssize_t aio_fork_pwrite_recv(struct tevent_req *req,
 772                                     struct vfs_aio_state *vfs_aio_state)
 773 {
 774         struct aio_fork_pwrite_state *state = tevent_req_data(
 775                 req, struct aio_fork_pwrite_state);
 776
 777         if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
 778                 return -1;
 779         }
 780         *vfs_aio_state = state->vfs_aio_state;
 781         return state->ret;
 782 }
 783
 784 struct aio_fork_fsync_state {
 785         struct aio_child *child;
 786         ssize_t ret;
 787         struct vfs_aio_state vfs_aio_state;
 788 };
 789
 790 static void aio_fork_fsync_done(struct tevent_req *subreq);
 791
 792 static struct tevent_req *aio_fork_fsync_send(
 793         struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
 794         struct tevent_context *ev, struct files_struct *fsp)
 795 {
 796         struct tevent_req *req, *subreq;
 797         struct aio_fork_fsync_state *state;
 798         struct rw_cmd cmd;
 799         ssize_t written;
 800         int err;
 801         struct aio_fork_config *config;
 802
 803         SMB_VFS_HANDLE_GET_DATA(handle, config,
 804                                 struct aio_fork_config,
 805                                 return NULL);
 806
 807         req = tevent_req_create(mem_ctx, &state, struct aio_fork_fsync_state);
 808         if (req == NULL) {
 809                 return NULL;
 810         }
 811
 812         err = get_idle_child(handle, &state->child);
 813         if (err != 0) {
 814                 tevent_req_error(req, err);
 815                 return tevent_req_post(req, ev);
 816         }
 817
 818         ZERO_STRUCT(cmd);
 819         cmd.cmd = FSYNC_CMD;
 820         cmd.erratic_testing_mode = config->erratic_testing_mode;
 821
 822         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 823                    (int)state->child->pid));
 824
 825         /*
 826          * Not making this async. We're writing into an empty unix
 827          * domain socket. This should never block.
 828          */
 829         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 830                            fsp->fh->fd);
 831         if (written == -1) {
 832                 err = errno;
 833
 834                 TALLOC_FREE(state->child);
 835
 836                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 837                 tevent_req_error(req, err);
 838                 return tevent_req_post(req, ev);
 839         }
 840
 841         subreq = read_packet_send(state, ev, state->child->sockfd,
 842                                   sizeof(struct rw_ret), NULL, NULL);
 843         if (tevent_req_nomem(subreq, req)) {
 844                 TALLOC_FREE(state->child); /* we sent sth down */
 845                 return tevent_req_post(req, ev);
 846         }
 847         tevent_req_set_callback(subreq, aio_fork_fsync_done, req);
 848         return req;
 849 }
 850
 851 static void aio_fork_fsync_done(struct tevent_req *subreq)
 852 {
 853         struct tevent_req *req = tevent_req_callback_data(
 854                 subreq, struct tevent_req);
 855         struct aio_fork_fsync_state *state = tevent_req_data(
 856                 req, struct aio_fork_fsync_state);
 857         ssize_t nread;
 858         uint8_t *buf;
 859         int err;
 860         struct rw_ret *retbuf;
 861
 862         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 863         TALLOC_FREE(subreq);
 864         if (nread == -1) {
 865                 TALLOC_FREE(state->child);
 866                 tevent_req_error(req, err);
 867                 return;
 868         }
 869
 870         state->child->busy = false;
 871
 872         retbuf = (struct rw_ret *)buf;
 873         state->ret = retbuf->size;
 874         state->vfs_aio_state.error = retbuf->ret_errno;
 875         state->vfs_aio_state.duration = retbuf->duration;
 876         tevent_req_done(req);
 877 }
 878
 879 static int aio_fork_fsync_recv(struct tevent_req *req,
 880                                struct vfs_aio_state *vfs_aio_state)
 881 {
 882         struct aio_fork_fsync_state *state = tevent_req_data(
 883                 req, struct aio_fork_fsync_state);
 884
 885         if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
 886                 return -1;
 887         }
 888         *vfs_aio_state = state->vfs_aio_state;
 889         return state->ret;
 890 }
 891
 892 static int aio_fork_connect(vfs_handle_struct *handle, const char *service,
 893                             const char *user)
 894 {
 895         int ret;
 896         struct aio_fork_config *config;
 897         ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 898
 899         if (ret < 0) {
 900                 return ret;
 901         }
 902
 903         config = talloc_zero(handle->conn, struct aio_fork_config);
 904         if (!config) {
 905                 SMB_VFS_NEXT_DISCONNECT(handle);
 906                 DEBUG(0, ("talloc_zero() failed\n"));
 907                 return -1;
 908         }
 909
 910         config->erratic_testing_mode = lp_parm_bool(SNUM(handle->conn), "vfs_aio_fork",
 911                                                     "erratic_testing_mode", false);
 912
 913         SMB_VFS_HANDLE_SET_DATA(handle, config,
 914                                 NULL, struct aio_fork_config,
 915                                 return -1);
 916
 917         return 0;
 918 }
 919
 920 static struct vfs_fn_pointers vfs_aio_fork_fns = {
 921         .connect_fn = aio_fork_connect,
 922         .pread_send_fn = aio_fork_pread_send,
 923         .pread_recv_fn = aio_fork_pread_recv,
 924         .pwrite_send_fn = aio_fork_pwrite_send,
 925         .pwrite_recv_fn = aio_fork_pwrite_recv,
 926         .fsync_send_fn = aio_fork_fsync_send,
 927         .fsync_recv_fn = aio_fork_fsync_recv,
 928 };
 929
 930 static_decl_vfs;
 931 NTSTATUS vfs_aio_fork_init(TALLOC_CTX *ctx)
 932 {
 933         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 934                                 "aio_fork", &vfs_aio_fork_fns);
 935 }