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 #include "lib/global_contexts.h"
  34
  35 #if !defined(HAVE_STRUCT_MSGHDR_MSG_CONTROL) && !defined(HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS)
  36 # error Can not pass file descriptors
  37 #endif
  38
  39 #undef recvmsg
  40
  41 #ifndef MAP_FILE
  42 #define MAP_FILE 0
  43 #endif
  44
  45 struct aio_child_list;
  46
  47 struct aio_fork_config {
  48         bool erratic_testing_mode;
  49         struct aio_child_list *children;
  50 };
  51
  52 struct mmap_area {
  53         size_t size;
  54         void *ptr;
  55 };
  56
  57 static int mmap_area_destructor(struct mmap_area *area)
  58 {
  59         munmap(discard_const(area->ptr), area->size);
  60         return 0;
  61 }
  62
  63 static struct mmap_area *mmap_area_init(TALLOC_CTX *mem_ctx, size_t size)
  64 {
  65         struct mmap_area *result;
  66         int fd;
  67
  68         result = talloc(mem_ctx, struct mmap_area);
  69         if (result == NULL) {
  70                 DEBUG(0, ("talloc failed\n"));
  71                 goto fail;
  72         }
  73
  74         fd = open("/dev/zero", O_RDWR);
  75         if (fd == -1) {
  76                 DEBUG(3, ("open(\"/dev/zero\") failed: %s\n",
  77                           strerror(errno)));
  78                 goto fail;
  79         }
  80
  81         result->ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
  82                            MAP_SHARED|MAP_FILE, fd, 0);
  83         close(fd);
  84         if (result->ptr == MAP_FAILED) {
  85                 DEBUG(1, ("mmap failed: %s\n", strerror(errno)));
  86                 goto fail;
  87         }
  88
  89         result->size = size;
  90         talloc_set_destructor(result, mmap_area_destructor);
  91
  92         return result;
  93
  94 fail:
  95         TALLOC_FREE(result);
  96         return NULL;
  97 }
  98
  99 enum cmd_type {
 100         READ_CMD,
 101         WRITE_CMD,
 102         FSYNC_CMD
 103 };
 104
 105 static const char *cmd_type_str(enum cmd_type cmd)
 106 {
 107         const char *result;
 108
 109         switch (cmd) {
 110         case READ_CMD:
 111                 result = "READ";
 112                 break;
 113         case WRITE_CMD:
 114                 result = "WRITE";
 115                 break;
 116         case FSYNC_CMD:
 117                 result = "FSYNC";
 118                 break;
 119         default:
 120                 result = "<UNKNOWN>";
 121                 break;
 122         }
 123         return result;
 124 }
 125
 126 struct rw_cmd {
 127         size_t n;
 128         off_t offset;
 129         enum cmd_type cmd;
 130         bool erratic_testing_mode;
 131 };
 132
 133 struct rw_ret {
 134         ssize_t size;
 135         int ret_errno;
 136         uint64_t duration;
 137 };
 138
 139 struct aio_child_list;
 140
 141 struct aio_child {
 142         struct aio_child *prev, *next;
 143         struct aio_child_list *list;
 144         pid_t pid;
 145         int sockfd;
 146         struct mmap_area *map;
 147         bool dont_delete;       /* Marked as in use since last cleanup */
 148         bool busy;
 149 };
 150
 151 struct aio_child_list {
 152         struct aio_child *children;
 153         struct tevent_timer *cleanup_event;
 154 };
 155
 156 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
 157 {
 158         struct iovec iov[1];
 159         struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1 };
 160         ssize_t n;
 161         size_t bufsize = msghdr_prep_recv_fds(NULL, NULL, 0, 1);
 162         uint8_t buf[bufsize];
 163
 164         msghdr_prep_recv_fds(&msg, buf, bufsize, 1);
 165
 166         iov[0].iov_base = (void *)ptr;
 167         iov[0].iov_len = nbytes;
 168
 169         do {
 170                 n = recvmsg(fd, &msg, 0);
 171         } while ((n == -1) && (errno == EINTR));
 172
 173         if (n <= 0) {
 174                 return n;
 175         }
 176
 177         {
 178                 size_t num_fds = msghdr_extract_fds(&msg, NULL, 0);
 179                 int fds[num_fds];
 180
 181                 msghdr_extract_fds(&msg, fds, num_fds);
 182
 183                 if (num_fds != 1) {
 184                         size_t i;
 185
 186                         for (i=0; i<num_fds; i++) {
 187                                 close(fds[i]);
 188                         }
 189
 190                         *recvfd = -1;
 191                         return n;
 192                 }
 193
 194                 *recvfd = fds[0];
 195         }
 196
 197         return(n);
 198 }
 199
 200 static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd)
 201 {
 202         struct msghdr msg = {0};
 203         size_t bufsize = msghdr_prep_fds(NULL, NULL, 0, &sendfd, 1);
 204         uint8_t buf[bufsize];
 205         struct iovec iov;
 206         ssize_t sent;
 207
 208         msghdr_prep_fds(&msg, buf, bufsize, &sendfd, 1);
 209
 210         iov.iov_base = (void *)ptr;
 211         iov.iov_len = nbytes;
 212         msg.msg_iov = &iov;
 213         msg.msg_iovlen = 1;
 214
 215         do {
 216                 sent = sendmsg(fd, &msg, 0);
 217         } while ((sent == -1) && (errno == EINTR));
 218
 219         return sent;
 220 }
 221
 222 static void aio_child_cleanup(struct tevent_context *event_ctx,
 223                               struct tevent_timer *te,
 224                               struct timeval now,
 225                               void *private_data)
 226 {
 227         struct aio_child_list *list = talloc_get_type_abort(
 228                 private_data, struct aio_child_list);
 229         struct aio_child *child, *next;
 230
 231         TALLOC_FREE(list->cleanup_event);
 232
 233         for (child = list->children; child != NULL; child = next) {
 234                 next = child->next;
 235
 236                 if (child->busy) {
 237                         DEBUG(10, ("child %d currently active\n",
 238                                    (int)child->pid));
 239                         continue;
 240                 }
 241
 242                 if (child->dont_delete) {
 243                         DEBUG(10, ("Child %d was active since last cleanup\n",
 244                                    (int)child->pid));
 245                         child->dont_delete = false;
 246                         continue;
 247                 }
 248
 249                 DEBUG(10, ("Child %d idle for more than 30 seconds, "
 250                            "deleting\n", (int)child->pid));
 251
 252                 TALLOC_FREE(child);
 253                 child = next;
 254         }
 255
 256         if (list->children != NULL) {
 257                 /*
 258                  * Re-schedule the next cleanup round
 259                  */
 260                 list->cleanup_event = tevent_add_timer(global_event_context(), list,
 261                                                       timeval_add(&now, 30, 0),
 262                                                       aio_child_cleanup, list);
 263
 264         }
 265 }
 266
 267 static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle)
 268 {
 269         struct aio_fork_config *config;
 270         struct aio_child_list *children;
 271
 272         SMB_VFS_HANDLE_GET_DATA(handle, config, struct aio_fork_config,
 273                                 return NULL);
 274
 275         if (config->children == NULL) {
 276                 config->children = talloc_zero(config, struct aio_child_list);
 277                 if (config->children == NULL) {
 278                         return NULL;
 279                 }
 280         }
 281         children = config->children;
 282
 283         /*
 284          * Regardless of whether the child_list had been around or not, make
 285          * sure that we have a cleanup timed event. This timed event will
 286          * delete itself when it finds that no children are around anymore.
 287          */
 288
 289         if (children->cleanup_event == NULL) {
 290                 children->cleanup_event =
 291                         tevent_add_timer(global_event_context(), children,
 292                                          timeval_current_ofs(30, 0),
 293                                          aio_child_cleanup, children);
 294                 if (children->cleanup_event == NULL) {
 295                         TALLOC_FREE(config->children);
 296                         return NULL;
 297                 }
 298         }
 299
 300         return children;
 301 }
 302
 303 static void aio_child_loop(int sockfd, struct mmap_area *map)
 304 {
 305         while (true) {
 306                 int fd = -1;
 307                 ssize_t ret;
 308                 struct rw_cmd cmd_struct;
 309                 struct rw_ret ret_struct;
 310                 struct timespec start, end;
 311
 312                 ret = read_fd(sockfd, &cmd_struct, sizeof(cmd_struct), &fd);
 313                 if (ret != sizeof(cmd_struct)) {
 314                         DEBUG(10, ("read_fd returned %d: %s\n", (int)ret,
 315                                    strerror(errno)));
 316                         exit(1);
 317                 }
 318
 319                 DEBUG(10, ("aio_child_loop: %s %d bytes at %d from fd %d\n",
 320                            cmd_type_str(cmd_struct.cmd),
 321                            (int)cmd_struct.n, (int)cmd_struct.offset, fd));
 322
 323                 if (cmd_struct.erratic_testing_mode) {
 324                         /*
 325                          * For developer testing, we want erratic behaviour for
 326                          * async I/O times
 327                          */
 328                         uint8_t randval;
 329                         unsigned msecs;
 330                         /*
 331                          * use generate_random_buffer, we just forked from a
 332                          * common parent state
 333                          */
 334                         generate_random_buffer(&randval, sizeof(randval));
 335                         msecs = (randval%20)+1;
 336                         DEBUG(10, ("delaying for %u msecs\n", msecs));
 337                         smb_msleep(msecs);
 338                 }
 339
 340                 ZERO_STRUCT(ret_struct);
 341
 342                 PROFILE_TIMESTAMP(&start);
 343
 344                 switch (cmd_struct.cmd) {
 345                 case READ_CMD:
 346                         ret_struct.size = sys_pread_full(
 347                                 fd, discard_const(map->ptr), cmd_struct.n,
 348                                 cmd_struct.offset);
 349 #if 0
 350 /* This breaks "make test" when run with aio_fork module. */
 351 #ifdef DEVELOPER
 352                         ret_struct.size = MAX(1, ret_struct.size * 0.9);
 353 #endif
 354 #endif
 355                         break;
 356                 case WRITE_CMD:
 357                         ret_struct.size = sys_pwrite_full(
 358                                 fd, discard_const(map->ptr), cmd_struct.n,
 359                                 cmd_struct.offset);
 360                         break;
 361                 case FSYNC_CMD:
 362                         ret_struct.size = fsync(fd);
 363                         break;
 364                 default:
 365                         ret_struct.size = -1;
 366                         errno = EINVAL;
 367                 }
 368
 369                 PROFILE_TIMESTAMP(&end);
 370                 ret_struct.duration = nsec_time_diff(&end, &start);
 371                 DEBUG(10, ("aio_child_loop: syscall returned %d\n",
 372                            (int)ret_struct.size));
 373
 374                 if (ret_struct.size == -1) {
 375                         ret_struct.ret_errno = errno;
 376                 }
 377
 378                 /*
 379                  * Close the fd before telling our parent we're done. The
 380                  * parent might close and re-open the file very quickly, and
 381                  * with system-level share modes (GPFS) we would get an
 382                  * unjustified SHARING_VIOLATION.
 383                  */
 384                 close(fd);
 385
 386                 ret = write_data(sockfd, (char *)&ret_struct,
 387                                  sizeof(ret_struct));
 388                 if (ret != sizeof(ret_struct)) {
 389                         DEBUG(10, ("could not write ret_struct: %s\n",
 390                                    strerror(errno)));
 391                         exit(2);
 392                 }
 393         }
 394 }
 395
 396 static int aio_child_destructor(struct aio_child *child)
 397 {
 398         char c=0;
 399
 400         SMB_ASSERT(!child->busy);
 401
 402         DEBUG(10, ("aio_child_destructor: removing child %d on fd %d\n",
 403                    (int)child->pid, child->sockfd));
 404
 405         /*
 406          * closing the sockfd makes the child not return from recvmsg() on RHEL
 407          * 5.5 so instead force the child to exit by writing bad data to it
 408          */
 409         sys_write_v(child->sockfd, &c, sizeof(c));
 410         close(child->sockfd);
 411         DLIST_REMOVE(child->list->children, child);
 412         return 0;
 413 }
 414
 415 /*
 416  * We have to close all fd's in open files, we might incorrectly hold a system
 417  * level share mode on a file.
 418  */
 419
 420 static struct files_struct *close_fsp_fd(struct files_struct *fsp,
 421                                          void *private_data)
 422 {
 423         if ((fsp->fh != NULL) && (fsp_get_pathref_fd(fsp) != -1)) {
 424                 close(fsp_get_pathref_fd(fsp));
 425                 fsp_set_fd(fsp, -1);
 426         }
 427         return NULL;
 428 }
 429
 430 static int create_aio_child(struct smbd_server_connection *sconn,
 431                             struct aio_child_list *children,
 432                             size_t map_size,
 433                             struct aio_child **presult)
 434 {
 435         struct aio_child *result;
 436         int fdpair[2];
 437         int ret;
 438
 439         fdpair[0] = fdpair[1] = -1;
 440
 441         result = talloc_zero(children, struct aio_child);
 442         if (result == NULL) {
 443                 return ENOMEM;
 444         }
 445
 446         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
 447                 ret = errno;
 448                 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
 449                 goto fail;
 450         }
 451
 452         DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
 453
 454         result->map = mmap_area_init(result, map_size);
 455         if (result->map == NULL) {
 456                 ret = errno;
 457                 DEBUG(0, ("Could not create mmap area\n"));
 458                 goto fail;
 459         }
 460
 461         result->pid = fork();
 462         if (result->pid == -1) {
 463                 ret = errno;
 464                 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
 465                 goto fail;
 466         }
 467
 468         if (result->pid == 0) {
 469                 close(fdpair[0]);
 470                 result->sockfd = fdpair[1];
 471                 files_forall(sconn, close_fsp_fd, NULL);
 472                 aio_child_loop(result->sockfd, result->map);
 473         }
 474
 475         DEBUG(10, ("Child %d created with sockfd %d\n",
 476                    (int)result->pid, fdpair[0]));
 477
 478         result->sockfd = fdpair[0];
 479         close(fdpair[1]);
 480
 481         result->list = children;
 482         DLIST_ADD(children->children, result);
 483
 484         talloc_set_destructor(result, aio_child_destructor);
 485
 486         *presult = result;
 487
 488         return 0;
 489
 490  fail:
 491         if (fdpair[0] != -1) close(fdpair[0]);
 492         if (fdpair[1] != -1) close(fdpair[1]);
 493         TALLOC_FREE(result);
 494
 495         return ret;
 496 }
 497
 498 static int get_idle_child(struct vfs_handle_struct *handle,
 499                           struct aio_child **pchild)
 500 {
 501         struct aio_child_list *children;
 502         struct aio_child *child;
 503
 504         children = init_aio_children(handle);
 505         if (children == NULL) {
 506                 return ENOMEM;
 507         }
 508
 509         for (child = children->children; child != NULL; child = child->next) {
 510                 if (!child->busy) {
 511                         break;
 512                 }
 513         }
 514
 515         if (child == NULL) {
 516                 int ret;
 517
 518                 DEBUG(10, ("no idle child found, creating new one\n"));
 519
 520                 ret = create_aio_child(handle->conn->sconn, children,
 521                                           128*1024, &child);
 522                 if (ret != 0) {
 523                         DEBUG(10, ("create_aio_child failed: %s\n",
 524                                    strerror(errno)));
 525                         return ret;
 526                 }
 527         }
 528
 529         child->dont_delete = true;
 530         child->busy = true;
 531
 532         *pchild = child;
 533         return 0;
 534 }
 535
 536 struct aio_fork_pread_state {
 537         struct aio_child *child;
 538         size_t n;
 539         void *data;
 540         ssize_t ret;
 541         struct vfs_aio_state vfs_aio_state;
 542 };
 543
 544 static void aio_fork_pread_done(struct tevent_req *subreq);
 545
 546 static struct tevent_req *aio_fork_pread_send(struct vfs_handle_struct *handle,
 547                                               TALLOC_CTX *mem_ctx,
 548                                               struct tevent_context *ev,
 549                                               struct files_struct *fsp,
 550                                               void *data,
 551                                               size_t n, off_t offset)
 552 {
 553         struct tevent_req *req, *subreq;
 554         struct aio_fork_pread_state *state;
 555         struct rw_cmd cmd;
 556         ssize_t written;
 557         int err;
 558         struct aio_fork_config *config;
 559
 560         SMB_VFS_HANDLE_GET_DATA(handle, config,
 561                                 struct aio_fork_config,
 562                                 return NULL);
 563
 564         req = tevent_req_create(mem_ctx, &state, struct aio_fork_pread_state);
 565         if (req == NULL) {
 566                 return NULL;
 567         }
 568         state->n = n;
 569         state->data = data;
 570
 571         if (n > 128*1024) {
 572                 /* TODO: support variable buffers */
 573                 tevent_req_error(req, EINVAL);
 574                 return tevent_req_post(req, ev);
 575         }
 576
 577         err = get_idle_child(handle, &state->child);
 578         if (err != 0) {
 579                 tevent_req_error(req, err);
 580                 return tevent_req_post(req, ev);
 581         }
 582
 583         ZERO_STRUCT(cmd);
 584         cmd.n = n;
 585         cmd.offset = offset;
 586         cmd.cmd = READ_CMD;
 587         cmd.erratic_testing_mode = config->erratic_testing_mode;
 588
 589         DEBUG(10, ("sending fd %d to child %d\n", fsp_get_io_fd(fsp),
 590                    (int)state->child->pid));
 591
 592         /*
 593          * Not making this async. We're writing into an empty unix
 594          * domain socket. This should never block.
 595          */
 596         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 597                            fsp_get_io_fd(fsp));
 598         if (written == -1) {
 599                 err = errno;
 600
 601                 TALLOC_FREE(state->child);
 602
 603                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 604                 tevent_req_error(req, err);
 605                 return tevent_req_post(req, ev);
 606         }
 607
 608         subreq = read_packet_send(state, ev, state->child->sockfd,
 609                                   sizeof(struct rw_ret), NULL, NULL);
 610         if (tevent_req_nomem(subreq, req)) {
 611                 TALLOC_FREE(state->child); /* we sent sth down */
 612                 return tevent_req_post(req, ev);
 613         }
 614         tevent_req_set_callback(subreq, aio_fork_pread_done, req);
 615         return req;
 616 }
 617
 618 static void aio_fork_pread_done(struct tevent_req *subreq)
 619 {
 620         struct tevent_req *req = tevent_req_callback_data(
 621                 subreq, struct tevent_req);
 622         struct aio_fork_pread_state *state = tevent_req_data(
 623                 req, struct aio_fork_pread_state);
 624         ssize_t nread;
 625         uint8_t *buf;
 626         int err;
 627         struct rw_ret *retbuf;
 628
 629         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 630         TALLOC_FREE(subreq);
 631         if (nread == -1) {
 632                 TALLOC_FREE(state->child);
 633                 tevent_req_error(req, err);
 634                 return;
 635         }
 636
 637         retbuf = (struct rw_ret *)buf;
 638         state->ret = retbuf->size;
 639         state->vfs_aio_state.error = retbuf->ret_errno;
 640         state->vfs_aio_state.duration = retbuf->duration;
 641
 642         if ((size_t)state->ret > state->n) {
 643                 tevent_req_error(req, EIO);
 644                 state->child->busy = false;
 645                 return;
 646         }
 647         memcpy(state->data, state->child->map->ptr, state->ret);
 648
 649         state->child->busy = false;
 650
 651         tevent_req_done(req);
 652 }
 653
 654 static ssize_t aio_fork_pread_recv(struct tevent_req *req,
 655                                    struct vfs_aio_state *vfs_aio_state)
 656 {
 657         struct aio_fork_pread_state *state = tevent_req_data(
 658                 req, struct aio_fork_pread_state);
 659
 660         if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
 661                 return -1;
 662         }
 663         *vfs_aio_state = state->vfs_aio_state;
 664         return state->ret;
 665 }
 666
 667 struct aio_fork_pwrite_state {
 668         struct aio_child *child;
 669         ssize_t ret;
 670         struct vfs_aio_state vfs_aio_state;
 671 };
 672
 673 static void aio_fork_pwrite_done(struct tevent_req *subreq);
 674
 675 static struct tevent_req *aio_fork_pwrite_send(
 676         struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
 677         struct tevent_context *ev, struct files_struct *fsp,
 678         const void *data, size_t n, off_t offset)
 679 {
 680         struct tevent_req *req, *subreq;
 681         struct aio_fork_pwrite_state *state;
 682         struct rw_cmd cmd;
 683         ssize_t written;
 684         int err;
 685         struct aio_fork_config *config;
 686         SMB_VFS_HANDLE_GET_DATA(handle, config,
 687                                 struct aio_fork_config,
 688                                 return NULL);
 689
 690         req = tevent_req_create(mem_ctx, &state, struct aio_fork_pwrite_state);
 691         if (req == NULL) {
 692                 return NULL;
 693         }
 694
 695         if (n > 128*1024) {
 696                 /* TODO: support variable buffers */
 697                 tevent_req_error(req, EINVAL);
 698                 return tevent_req_post(req, ev);
 699         }
 700
 701         err = get_idle_child(handle, &state->child);
 702         if (err != 0) {
 703                 tevent_req_error(req, err);
 704                 return tevent_req_post(req, ev);
 705         }
 706
 707         memcpy(state->child->map->ptr, data, n);
 708
 709         ZERO_STRUCT(cmd);
 710         cmd.n = n;
 711         cmd.offset = offset;
 712         cmd.cmd = WRITE_CMD;
 713         cmd.erratic_testing_mode = config->erratic_testing_mode;
 714
 715         DEBUG(10, ("sending fd %d to child %d\n", fsp_get_io_fd(fsp),
 716                    (int)state->child->pid));
 717
 718         /*
 719          * Not making this async. We're writing into an empty unix
 720          * domain socket. This should never block.
 721          */
 722         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 723                            fsp_get_io_fd(fsp));
 724         if (written == -1) {
 725                 err = errno;
 726
 727                 TALLOC_FREE(state->child);
 728
 729                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 730                 tevent_req_error(req, err);
 731                 return tevent_req_post(req, ev);
 732         }
 733
 734         subreq = read_packet_send(state, ev, state->child->sockfd,
 735                                   sizeof(struct rw_ret), NULL, NULL);
 736         if (tevent_req_nomem(subreq, req)) {
 737                 TALLOC_FREE(state->child); /* we sent sth down */
 738                 return tevent_req_post(req, ev);
 739         }
 740         tevent_req_set_callback(subreq, aio_fork_pwrite_done, req);
 741         return req;
 742 }
 743
 744 static void aio_fork_pwrite_done(struct tevent_req *subreq)
 745 {
 746         struct tevent_req *req = tevent_req_callback_data(
 747                 subreq, struct tevent_req);
 748         struct aio_fork_pwrite_state *state = tevent_req_data(
 749                 req, struct aio_fork_pwrite_state);
 750         ssize_t nread;
 751         uint8_t *buf;
 752         int err;
 753         struct rw_ret *retbuf;
 754
 755         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 756         TALLOC_FREE(subreq);
 757         if (nread == -1) {
 758                 TALLOC_FREE(state->child);
 759                 tevent_req_error(req, err);
 760                 return;
 761         }
 762
 763         state->child->busy = false;
 764
 765         retbuf = (struct rw_ret *)buf;
 766         state->ret = retbuf->size;
 767         state->vfs_aio_state.error = retbuf->ret_errno;
 768         state->vfs_aio_state.duration = retbuf->duration;
 769         tevent_req_done(req);
 770 }
 771
 772 static ssize_t aio_fork_pwrite_recv(struct tevent_req *req,
 773                                     struct vfs_aio_state *vfs_aio_state)
 774 {
 775         struct aio_fork_pwrite_state *state = tevent_req_data(
 776                 req, struct aio_fork_pwrite_state);
 777
 778         if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
 779                 return -1;
 780         }
 781         *vfs_aio_state = state->vfs_aio_state;
 782         return state->ret;
 783 }
 784
 785 struct aio_fork_fsync_state {
 786         struct aio_child *child;
 787         ssize_t ret;
 788         struct vfs_aio_state vfs_aio_state;
 789 };
 790
 791 static void aio_fork_fsync_done(struct tevent_req *subreq);
 792
 793 static struct tevent_req *aio_fork_fsync_send(
 794         struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
 795         struct tevent_context *ev, struct files_struct *fsp)
 796 {
 797         struct tevent_req *req, *subreq;
 798         struct aio_fork_fsync_state *state;
 799         struct rw_cmd cmd;
 800         ssize_t written;
 801         int err;
 802         struct aio_fork_config *config;
 803
 804         SMB_VFS_HANDLE_GET_DATA(handle, config,
 805                                 struct aio_fork_config,
 806                                 return NULL);
 807
 808         req = tevent_req_create(mem_ctx, &state, struct aio_fork_fsync_state);
 809         if (req == NULL) {
 810                 return NULL;
 811         }
 812
 813         err = get_idle_child(handle, &state->child);
 814         if (err != 0) {
 815                 tevent_req_error(req, err);
 816                 return tevent_req_post(req, ev);
 817         }
 818
 819         ZERO_STRUCT(cmd);
 820         cmd.cmd = FSYNC_CMD;
 821         cmd.erratic_testing_mode = config->erratic_testing_mode;
 822
 823         DEBUG(10, ("sending fd %d to child %d\n", fsp_get_io_fd(fsp),
 824                    (int)state->child->pid));
 825
 826         /*
 827          * Not making this async. We're writing into an empty unix
 828          * domain socket. This should never block.
 829          */
 830         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 831                            fsp_get_io_fd(fsp));
 832         if (written == -1) {
 833                 err = errno;
 834
 835                 TALLOC_FREE(state->child);
 836
 837                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 838                 tevent_req_error(req, err);
 839                 return tevent_req_post(req, ev);
 840         }
 841
 842         subreq = read_packet_send(state, ev, state->child->sockfd,
 843                                   sizeof(struct rw_ret), NULL, NULL);
 844         if (tevent_req_nomem(subreq, req)) {
 845                 TALLOC_FREE(state->child); /* we sent sth down */
 846                 return tevent_req_post(req, ev);
 847         }
 848         tevent_req_set_callback(subreq, aio_fork_fsync_done, req);
 849         return req;
 850 }
 851
 852 static void aio_fork_fsync_done(struct tevent_req *subreq)
 853 {
 854         struct tevent_req *req = tevent_req_callback_data(
 855                 subreq, struct tevent_req);
 856         struct aio_fork_fsync_state *state = tevent_req_data(
 857                 req, struct aio_fork_fsync_state);
 858         ssize_t nread;
 859         uint8_t *buf;
 860         int err;
 861         struct rw_ret *retbuf;
 862
 863         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 864         TALLOC_FREE(subreq);
 865         if (nread == -1) {
 866                 TALLOC_FREE(state->child);
 867                 tevent_req_error(req, err);
 868                 return;
 869         }
 870
 871         state->child->busy = false;
 872
 873         retbuf = (struct rw_ret *)buf;
 874         state->ret = retbuf->size;
 875         state->vfs_aio_state.error = retbuf->ret_errno;
 876         state->vfs_aio_state.duration = retbuf->duration;
 877         tevent_req_done(req);
 878 }
 879
 880 static int aio_fork_fsync_recv(struct tevent_req *req,
 881                                struct vfs_aio_state *vfs_aio_state)
 882 {
 883         struct aio_fork_fsync_state *state = tevent_req_data(
 884                 req, struct aio_fork_fsync_state);
 885
 886         if (tevent_req_is_unix_error(req, &vfs_aio_state->error)) {
 887                 return -1;
 888         }
 889         *vfs_aio_state = state->vfs_aio_state;
 890         return state->ret;
 891 }
 892
 893 static int aio_fork_connect(vfs_handle_struct *handle, const char *service,
 894                             const char *user)
 895 {
 896         int ret;
 897         struct aio_fork_config *config;
 898         ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 899
 900         if (ret < 0) {
 901                 return ret;
 902         }
 903
 904         config = talloc_zero(handle->conn, struct aio_fork_config);
 905         if (!config) {
 906                 SMB_VFS_NEXT_DISCONNECT(handle);
 907                 DEBUG(0, ("talloc_zero() failed\n"));
 908                 return -1;
 909         }
 910
 911         config->erratic_testing_mode = lp_parm_bool(SNUM(handle->conn), "vfs_aio_fork",
 912                                                     "erratic_testing_mode", false);
 913
 914         SMB_VFS_HANDLE_SET_DATA(handle, config,
 915                                 NULL, struct aio_fork_config,
 916                                 return -1);
 917
 918         return 0;
 919 }
 920
 921 static struct vfs_fn_pointers vfs_aio_fork_fns = {
 922         .connect_fn = aio_fork_connect,
 923         .pread_send_fn = aio_fork_pread_send,
 924         .pread_recv_fn = aio_fork_pread_recv,
 925         .pwrite_send_fn = aio_fork_pwrite_send,
 926         .pwrite_recv_fn = aio_fork_pwrite_recv,
 927         .fsync_send_fn = aio_fork_fsync_send,
 928         .fsync_recv_fn = aio_fork_fsync_recv,
 929 };
 930
 931 static_decl_vfs;
 932 NTSTATUS vfs_aio_fork_init(TALLOC_CTX *ctx)
 933 {
 934         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 935                                 "aio_fork", &vfs_aio_fork_fns);
 936 }