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
  30 #undef recvmsg
  31
  32 #ifndef MAP_FILE
  33 #define MAP_FILE 0
  34 #endif
  35
  36 struct aio_fork_config {
  37         bool erratic_testing_mode;
  38 };
  39
  40 struct mmap_area {
  41         size_t size;
  42         volatile void *ptr;
  43 };
  44
  45 static int mmap_area_destructor(struct mmap_area *area)
  46 {
  47         munmap((void *)area->ptr, area->size);
  48         return 0;
  49 }
  50
  51 static struct mmap_area *mmap_area_init(TALLOC_CTX *mem_ctx, size_t size)
  52 {
  53         struct mmap_area *result;
  54         int fd;
  55
  56         result = talloc(mem_ctx, struct mmap_area);
  57         if (result == NULL) {
  58                 DEBUG(0, ("talloc failed\n"));
  59                 goto fail;
  60         }
  61
  62         fd = open("/dev/zero", O_RDWR);
  63         if (fd == -1) {
  64                 DEBUG(3, ("open(\"/dev/zero\") failed: %s\n",
  65                           strerror(errno)));
  66                 goto fail;
  67         }
  68
  69         result->ptr = mmap(NULL, size, PROT_READ|PROT_WRITE,
  70                            MAP_SHARED|MAP_FILE, fd, 0);
  71         if (result->ptr == MAP_FAILED) {
  72                 DEBUG(1, ("mmap failed: %s\n", strerror(errno)));
  73                 goto fail;
  74         }
  75
  76         close(fd);
  77
  78         result->size = size;
  79         talloc_set_destructor(result, mmap_area_destructor);
  80
  81         return result;
  82
  83 fail:
  84         TALLOC_FREE(result);
  85         return NULL;
  86 }
  87
  88 enum cmd_type {
  89         READ_CMD,
  90         WRITE_CMD,
  91         FSYNC_CMD
  92 };
  93
  94 static const char *cmd_type_str(enum cmd_type cmd)
  95 {
  96         const char *result;
  97
  98         switch (cmd) {
  99         case READ_CMD:
 100                 result = "READ";
 101                 break;
 102         case WRITE_CMD:
 103                 result = "WRITE";
 104                 break;
 105         case FSYNC_CMD:
 106                 result = "FSYNC";
 107                 break;
 108         default:
 109                 result = "<UNKNOWN>";
 110                 break;
 111         }
 112         return result;
 113 }
 114
 115 struct rw_cmd {
 116         size_t n;
 117         off_t offset;
 118         enum cmd_type cmd;
 119         bool erratic_testing_mode;
 120 };
 121
 122 struct rw_ret {
 123         ssize_t size;
 124         int ret_errno;
 125 };
 126
 127 struct aio_child_list;
 128
 129 struct aio_child {
 130         struct aio_child *prev, *next;
 131         struct aio_child_list *list;
 132         pid_t pid;
 133         int sockfd;
 134         struct mmap_area *map;
 135         bool dont_delete;       /* Marked as in use since last cleanup */
 136         bool busy;
 137 };
 138
 139 struct aio_child_list {
 140         struct aio_child *children;
 141         struct tevent_timer *cleanup_event;
 142 };
 143
 144 static void free_aio_children(void **p)
 145 {
 146         TALLOC_FREE(*p);
 147 }
 148
 149 static ssize_t read_fd(int fd, void *ptr, size_t nbytes, int *recvfd)
 150 {
 151         struct msghdr msg;
 152         struct iovec iov[1];
 153         ssize_t n;
 154 #ifndef HAVE_MSGHDR_MSG_CONTROL
 155         int newfd;
 156 #endif
 157
 158 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 159         union {
 160           struct cmsghdr        cm;
 161           char                          control[CMSG_SPACE(sizeof(int))];
 162         } control_un;
 163         struct cmsghdr  *cmptr;
 164
 165         msg.msg_control = control_un.control;
 166         msg.msg_controllen = sizeof(control_un.control);
 167 #else
 168 #if HAVE_MSGHDR_MSG_ACCTRIGHTS
 169         msg.msg_accrights = (caddr_t) &newfd;
 170         msg.msg_accrightslen = sizeof(int);
 171 #else
 172 #error Can not pass file descriptors
 173 #endif
 174 #endif
 175
 176         msg.msg_name = NULL;
 177         msg.msg_namelen = 0;
 178         msg.msg_flags = 0;
 179
 180         iov[0].iov_base = (void *)ptr;
 181         iov[0].iov_len = nbytes;
 182         msg.msg_iov = iov;
 183         msg.msg_iovlen = 1;
 184
 185         if ( (n = recvmsg(fd, &msg, 0)) <= 0) {
 186                 return(n);
 187         }
 188
 189 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 190         if ((cmptr = CMSG_FIRSTHDR(&msg)) != NULL
 191             && cmptr->cmsg_len == CMSG_LEN(sizeof(int))) {
 192                 if (cmptr->cmsg_level != SOL_SOCKET) {
 193                         DEBUG(10, ("control level != SOL_SOCKET"));
 194                         errno = EINVAL;
 195                         return -1;
 196                 }
 197                 if (cmptr->cmsg_type != SCM_RIGHTS) {
 198                         DEBUG(10, ("control type != SCM_RIGHTS"));
 199                         errno = EINVAL;
 200                         return -1;
 201                 }
 202                 memcpy(recvfd, CMSG_DATA(cmptr), sizeof(*recvfd));
 203         } else {
 204                 *recvfd = -1;           /* descriptor was not passed */
 205         }
 206 #else
 207         if (msg.msg_accrightslen == sizeof(int)) {
 208                 *recvfd = newfd;
 209         }
 210         else {
 211                 *recvfd = -1;           /* descriptor was not passed */
 212         }
 213 #endif
 214
 215         return(n);
 216 }
 217
 218 static ssize_t write_fd(int fd, void *ptr, size_t nbytes, int sendfd)
 219 {
 220         struct msghdr   msg;
 221         struct iovec    iov[1];
 222
 223 #ifdef  HAVE_MSGHDR_MSG_CONTROL
 224         union {
 225                 struct cmsghdr  cm;
 226                 char control[CMSG_SPACE(sizeof(int))];
 227         } control_un;
 228         struct cmsghdr  *cmptr;
 229
 230         ZERO_STRUCT(msg);
 231         ZERO_STRUCT(control_un);
 232
 233         msg.msg_control = control_un.control;
 234         msg.msg_controllen = sizeof(control_un.control);
 235
 236         cmptr = CMSG_FIRSTHDR(&msg);
 237         cmptr->cmsg_len = CMSG_LEN(sizeof(int));
 238         cmptr->cmsg_level = SOL_SOCKET;
 239         cmptr->cmsg_type = SCM_RIGHTS;
 240         memcpy(CMSG_DATA(cmptr), &sendfd, sizeof(sendfd));
 241 #else
 242         ZERO_STRUCT(msg);
 243         msg.msg_accrights = (caddr_t) &sendfd;
 244         msg.msg_accrightslen = sizeof(int);
 245 #endif
 246
 247         msg.msg_name = NULL;
 248         msg.msg_namelen = 0;
 249
 250         ZERO_STRUCT(iov);
 251         iov[0].iov_base = (void *)ptr;
 252         iov[0].iov_len = nbytes;
 253         msg.msg_iov = iov;
 254         msg.msg_iovlen = 1;
 255
 256         return (sendmsg(fd, &msg, 0));
 257 }
 258
 259 static void aio_child_cleanup(struct tevent_context *event_ctx,
 260                               struct tevent_timer *te,
 261                               struct timeval now,
 262                               void *private_data)
 263 {
 264         struct aio_child_list *list = talloc_get_type_abort(
 265                 private_data, struct aio_child_list);
 266         struct aio_child *child, *next;
 267
 268         TALLOC_FREE(list->cleanup_event);
 269
 270         for (child = list->children; child != NULL; child = next) {
 271                 next = child->next;
 272
 273                 if (child->busy) {
 274                         DEBUG(10, ("child %d currently active\n",
 275                                    (int)child->pid));
 276                         continue;
 277                 }
 278
 279                 if (child->dont_delete) {
 280                         DEBUG(10, ("Child %d was active since last cleanup\n",
 281                                    (int)child->pid));
 282                         child->dont_delete = false;
 283                         continue;
 284                 }
 285
 286                 DEBUG(10, ("Child %d idle for more than 30 seconds, "
 287                            "deleting\n", (int)child->pid));
 288
 289                 TALLOC_FREE(child);
 290                 child = next;
 291         }
 292
 293         if (list->children != NULL) {
 294                 /*
 295                  * Re-schedule the next cleanup round
 296                  */
 297                 list->cleanup_event = event_add_timed(server_event_context(), list,
 298                                                       timeval_add(&now, 30, 0),
 299                                                       aio_child_cleanup, list);
 300
 301         }
 302 }
 303
 304 static struct aio_child_list *init_aio_children(struct vfs_handle_struct *handle)
 305 {
 306         struct aio_child_list *data = NULL;
 307
 308         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 309                 SMB_VFS_HANDLE_GET_DATA(handle, data, struct aio_child_list,
 310                                         return NULL);
 311         }
 312
 313         if (data == NULL) {
 314                 data = talloc_zero(NULL, struct aio_child_list);
 315                 if (data == NULL) {
 316                         return NULL;
 317                 }
 318         }
 319
 320         /*
 321          * Regardless of whether the child_list had been around or not, make
 322          * sure that we have a cleanup timed event. This timed event will
 323          * delete itself when it finds that no children are around anymore.
 324          */
 325
 326         if (data->cleanup_event == NULL) {
 327                 data->cleanup_event = event_add_timed(server_event_context(), data,
 328                                                       timeval_current_ofs(30, 0),
 329                                                       aio_child_cleanup, data);
 330                 if (data->cleanup_event == NULL) {
 331                         TALLOC_FREE(data);
 332                         return NULL;
 333                 }
 334         }
 335
 336         if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
 337                 SMB_VFS_HANDLE_SET_DATA(handle, data, free_aio_children,
 338                                         struct aio_child_list, return False);
 339         }
 340
 341         return data;
 342 }
 343
 344 static void aio_child_loop(int sockfd, struct mmap_area *map)
 345 {
 346         while (true) {
 347                 int fd = -1;
 348                 ssize_t ret;
 349                 struct rw_cmd cmd_struct;
 350                 struct rw_ret ret_struct;
 351
 352                 ret = read_fd(sockfd, &cmd_struct, sizeof(cmd_struct), &fd);
 353                 if (ret != sizeof(cmd_struct)) {
 354                         DEBUG(10, ("read_fd returned %d: %s\n", (int)ret,
 355                                    strerror(errno)));
 356                         exit(1);
 357                 }
 358
 359                 DEBUG(10, ("aio_child_loop: %s %d bytes at %d from fd %d\n",
 360                            cmd_type_str(cmd_struct.cmd),
 361                            (int)cmd_struct.n, (int)cmd_struct.offset, fd));
 362
 363                 if (cmd_struct.erratic_testing_mode) {
 364                         /*
 365                          * For developer testing, we want erratic behaviour for
 366                          * async I/O times
 367                          */
 368                         uint8_t randval;
 369                         unsigned msecs;
 370                         /*
 371                          * use generate_random_buffer, we just forked from a
 372                          * common parent state
 373                          */
 374                         generate_random_buffer(&randval, sizeof(randval));
 375                         msecs = randval + 20;
 376                         DEBUG(10, ("delaying for %u msecs\n", msecs));
 377                         smb_msleep(msecs);
 378                 }
 379
 380                 ZERO_STRUCT(ret_struct);
 381
 382                 switch (cmd_struct.cmd) {
 383                 case READ_CMD:
 384                         ret_struct.size = sys_pread(
 385                                 fd, (void *)map->ptr, cmd_struct.n,
 386                                 cmd_struct.offset);
 387 #if 0
 388 /* This breaks "make test" when run with aio_fork module. */
 389 #ifdef DEVELOPER
 390                         ret_struct.size = MAX(1, ret_struct.size * 0.9);
 391 #endif
 392 #endif
 393                         break;
 394                 case WRITE_CMD:
 395                         ret_struct.size = sys_pwrite(
 396                                 fd, (void *)map->ptr, cmd_struct.n,
 397                                 cmd_struct.offset);
 398                         break;
 399                 case FSYNC_CMD:
 400                         ret_struct.size = fsync(fd);
 401                         break;
 402                 default:
 403                         ret_struct.size = -1;
 404                         errno = EINVAL;
 405                 }
 406
 407                 DEBUG(10, ("aio_child_loop: syscall returned %d\n",
 408                            (int)ret_struct.size));
 409
 410                 if (ret_struct.size == -1) {
 411                         ret_struct.ret_errno = errno;
 412                 }
 413
 414                 /*
 415                  * Close the fd before telling our parent we're done. The
 416                  * parent might close and re-open the file very quickly, and
 417                  * with system-level share modes (GPFS) we would get an
 418                  * unjustified SHARING_VIOLATION.
 419                  */
 420                 close(fd);
 421
 422                 ret = write_data(sockfd, (char *)&ret_struct,
 423                                  sizeof(ret_struct));
 424                 if (ret != sizeof(ret_struct)) {
 425                         DEBUG(10, ("could not write ret_struct: %s\n",
 426                                    strerror(errno)));
 427                         exit(2);
 428                 }
 429         }
 430 }
 431
 432 static int aio_child_destructor(struct aio_child *child)
 433 {
 434         char c=0;
 435
 436         SMB_ASSERT(!child->busy);
 437
 438         DEBUG(10, ("aio_child_destructor: removing child %d on fd %d\n",
 439                         child->pid, child->sockfd));
 440
 441         /*
 442          * closing the sockfd makes the child not return from recvmsg() on RHEL
 443          * 5.5 so instead force the child to exit by writing bad data to it
 444          */
 445         write(child->sockfd, &c, sizeof(c));
 446         close(child->sockfd);
 447         DLIST_REMOVE(child->list->children, child);
 448         return 0;
 449 }
 450
 451 /*
 452  * We have to close all fd's in open files, we might incorrectly hold a system
 453  * level share mode on a file.
 454  */
 455
 456 static struct files_struct *close_fsp_fd(struct files_struct *fsp,
 457                                          void *private_data)
 458 {
 459         if ((fsp->fh != NULL) && (fsp->fh->fd != -1)) {
 460                 close(fsp->fh->fd);
 461                 fsp->fh->fd = -1;
 462         }
 463         return NULL;
 464 }
 465
 466 static int create_aio_child(struct smbd_server_connection *sconn,
 467                             struct aio_child_list *children,
 468                             size_t map_size,
 469                             struct aio_child **presult)
 470 {
 471         struct aio_child *result;
 472         int fdpair[2];
 473         int ret;
 474
 475         fdpair[0] = fdpair[1] = -1;
 476
 477         result = talloc_zero(children, struct aio_child);
 478         if (result == NULL) {
 479                 return ENOMEM;
 480         }
 481
 482         if (socketpair(AF_UNIX, SOCK_STREAM, 0, fdpair) == -1) {
 483                 ret = errno;
 484                 DEBUG(10, ("socketpair() failed: %s\n", strerror(errno)));
 485                 goto fail;
 486         }
 487
 488         DEBUG(10, ("fdpair = %d/%d\n", fdpair[0], fdpair[1]));
 489
 490         result->map = mmap_area_init(result, map_size);
 491         if (result->map == NULL) {
 492                 ret = errno;
 493                 DEBUG(0, ("Could not create mmap area\n"));
 494                 goto fail;
 495         }
 496
 497         result->pid = fork();
 498         if (result->pid == -1) {
 499                 ret = errno;
 500                 DEBUG(0, ("fork failed: %s\n", strerror(errno)));
 501                 goto fail;
 502         }
 503
 504         if (result->pid == 0) {
 505                 close(fdpair[0]);
 506                 result->sockfd = fdpair[1];
 507                 files_forall(sconn, close_fsp_fd, NULL);
 508                 aio_child_loop(result->sockfd, result->map);
 509         }
 510
 511         DEBUG(10, ("Child %d created with sockfd %d\n",
 512                         result->pid, fdpair[0]));
 513
 514         result->sockfd = fdpair[0];
 515         close(fdpair[1]);
 516
 517         result->list = children;
 518         DLIST_ADD(children->children, result);
 519
 520         talloc_set_destructor(result, aio_child_destructor);
 521
 522         *presult = result;
 523
 524         return 0;
 525
 526  fail:
 527         if (fdpair[0] != -1) close(fdpair[0]);
 528         if (fdpair[1] != -1) close(fdpair[1]);
 529         TALLOC_FREE(result);
 530
 531         return ret;
 532 }
 533
 534 static int get_idle_child(struct vfs_handle_struct *handle,
 535                           struct aio_child **pchild)
 536 {
 537         struct aio_child_list *children;
 538         struct aio_child *child;
 539
 540         children = init_aio_children(handle);
 541         if (children == NULL) {
 542                 return ENOMEM;
 543         }
 544
 545         for (child = children->children; child != NULL; child = child->next) {
 546                 if (!child->busy) {
 547                         break;
 548                 }
 549         }
 550
 551         if (child == NULL) {
 552                 int ret;
 553
 554                 DEBUG(10, ("no idle child found, creating new one\n"));
 555
 556                 ret = create_aio_child(handle->conn->sconn, children,
 557                                           128*1024, &child);
 558                 if (ret != 0) {
 559                         DEBUG(10, ("create_aio_child failed: %s\n",
 560                                    strerror(errno)));
 561                         return ret;
 562                 }
 563         }
 564
 565         child->dont_delete = true;
 566         child->busy = true;
 567
 568         *pchild = child;
 569         return 0;
 570 }
 571
 572 struct aio_fork_pread_state {
 573         struct aio_child *child;
 574         ssize_t ret;
 575         int err;
 576 };
 577
 578 static void aio_fork_pread_done(struct tevent_req *subreq);
 579
 580 static struct tevent_req *aio_fork_pread_send(struct vfs_handle_struct *handle,
 581                                               TALLOC_CTX *mem_ctx,
 582                                               struct tevent_context *ev,
 583                                               struct files_struct *fsp,
 584                                               void *data,
 585                                               size_t n, off_t offset)
 586 {
 587         struct tevent_req *req, *subreq;
 588         struct aio_fork_pread_state *state;
 589         struct rw_cmd cmd;
 590         ssize_t written;
 591         int err;
 592         struct aio_fork_config *config;
 593
 594         SMB_VFS_HANDLE_GET_DATA(handle, config,
 595                                 struct aio_fork_config,
 596                                 return NULL);
 597
 598         req = tevent_req_create(mem_ctx, &state, struct aio_fork_pread_state);
 599         if (req == NULL) {
 600                 return NULL;
 601         }
 602
 603         if (n > 128*1024) {
 604                 /* TODO: support variable buffers */
 605                 tevent_req_error(req, EINVAL);
 606                 return tevent_req_post(req, ev);
 607         }
 608
 609         err = get_idle_child(handle, &state->child);
 610         if (err != 0) {
 611                 tevent_req_error(req, err);
 612                 return tevent_req_post(req, ev);
 613         }
 614
 615         ZERO_STRUCT(cmd);
 616         cmd.n = n;
 617         cmd.offset = offset;
 618         cmd.cmd = READ_CMD;
 619         cmd.erratic_testing_mode = config->erratic_testing_mode;
 620
 621         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 622                    (int)state->child->pid));
 623
 624         /*
 625          * Not making this async. We're writing into an empty unix
 626          * domain socket. This should never block.
 627          */
 628         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 629                            fsp->fh->fd);
 630         if (written == -1) {
 631                 err = errno;
 632
 633                 TALLOC_FREE(state->child);
 634
 635                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 636                 tevent_req_error(req, err);
 637                 return tevent_req_post(req, ev);
 638         }
 639
 640         subreq = read_packet_send(state, ev, state->child->sockfd,
 641                                   sizeof(struct rw_ret), NULL, NULL);
 642         if (tevent_req_nomem(subreq, req)) {
 643                 TALLOC_FREE(state->child); /* we sent sth down */
 644                 return tevent_req_post(req, ev);
 645         }
 646         tevent_req_set_callback(subreq, aio_fork_pread_done, req);
 647         return req;
 648 }
 649
 650 static void aio_fork_pread_done(struct tevent_req *subreq)
 651 {
 652         struct tevent_req *req = tevent_req_callback_data(
 653                 subreq, struct tevent_req);
 654         struct aio_fork_pread_state *state = tevent_req_data(
 655                 req, struct aio_fork_pread_state);
 656         ssize_t nread;
 657         uint8_t *buf;
 658         int err;
 659         struct rw_ret *retbuf;
 660
 661         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 662         TALLOC_FREE(subreq);
 663         if (nread == -1) {
 664                 TALLOC_FREE(state->child);
 665                 tevent_req_error(req, err);
 666                 return;
 667         }
 668
 669         state->child->busy = false;
 670
 671         retbuf = (struct rw_ret *)buf;
 672         state->ret = retbuf->size;
 673         state->err = retbuf->ret_errno;
 674         tevent_req_done(req);
 675 }
 676
 677 static ssize_t aio_fork_pread_recv(struct tevent_req *req, int *err)
 678 {
 679         struct aio_fork_pread_state *state = tevent_req_data(
 680                 req, struct aio_fork_pread_state);
 681
 682         if (tevent_req_is_unix_error(req, err)) {
 683                 return -1;
 684         }
 685         if (state->ret == -1) {
 686                 *err = state->err;
 687         }
 688         return state->ret;
 689 }
 690
 691 struct aio_fork_pwrite_state {
 692         struct aio_child *child;
 693         ssize_t ret;
 694         int err;
 695 };
 696
 697 static void aio_fork_pwrite_done(struct tevent_req *subreq);
 698
 699 static struct tevent_req *aio_fork_pwrite_send(
 700         struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
 701         struct tevent_context *ev, struct files_struct *fsp,
 702         const void *data, size_t n, off_t offset)
 703 {
 704         struct tevent_req *req, *subreq;
 705         struct aio_fork_pwrite_state *state;
 706         struct rw_cmd cmd;
 707         ssize_t written;
 708         int err;
 709         struct aio_fork_config *config;
 710         SMB_VFS_HANDLE_GET_DATA(handle, config,
 711                                 struct aio_fork_config,
 712                                 return NULL);
 713
 714         req = tevent_req_create(mem_ctx, &state, struct aio_fork_pwrite_state);
 715         if (req == NULL) {
 716                 return NULL;
 717         }
 718
 719         if (n > 128*1024) {
 720                 /* TODO: support variable buffers */
 721                 tevent_req_error(req, EINVAL);
 722                 return tevent_req_post(req, ev);
 723         }
 724
 725         err = get_idle_child(handle, &state->child);
 726         if (err != 0) {
 727                 tevent_req_error(req, err);
 728                 return tevent_req_post(req, ev);
 729         }
 730
 731         ZERO_STRUCT(cmd);
 732         cmd.n = n;
 733         cmd.offset = offset;
 734         cmd.cmd = WRITE_CMD;
 735         cmd.erratic_testing_mode = config->erratic_testing_mode;
 736
 737         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 738                    (int)state->child->pid));
 739
 740         /*
 741          * Not making this async. We're writing into an empty unix
 742          * domain socket. This should never block.
 743          */
 744         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 745                            fsp->fh->fd);
 746         if (written == -1) {
 747                 err = errno;
 748
 749                 TALLOC_FREE(state->child);
 750
 751                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 752                 tevent_req_error(req, err);
 753                 return tevent_req_post(req, ev);
 754         }
 755
 756         subreq = read_packet_send(state, ev, state->child->sockfd,
 757                                   sizeof(struct rw_ret), NULL, NULL);
 758         if (tevent_req_nomem(subreq, req)) {
 759                 TALLOC_FREE(state->child); /* we sent sth down */
 760                 return tevent_req_post(req, ev);
 761         }
 762         tevent_req_set_callback(subreq, aio_fork_pwrite_done, req);
 763         return req;
 764 }
 765
 766 static void aio_fork_pwrite_done(struct tevent_req *subreq)
 767 {
 768         struct tevent_req *req = tevent_req_callback_data(
 769                 subreq, struct tevent_req);
 770         struct aio_fork_pwrite_state *state = tevent_req_data(
 771                 req, struct aio_fork_pwrite_state);
 772         ssize_t nread;
 773         uint8_t *buf;
 774         int err;
 775         struct rw_ret *retbuf;
 776
 777         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 778         TALLOC_FREE(subreq);
 779         if (nread == -1) {
 780                 TALLOC_FREE(state->child);
 781                 tevent_req_error(req, err);
 782                 return;
 783         }
 784
 785         state->child->busy = false;
 786
 787         retbuf = (struct rw_ret *)buf;
 788         state->ret = retbuf->size;
 789         state->err = retbuf->ret_errno;
 790         tevent_req_done(req);
 791 }
 792
 793 static ssize_t aio_fork_pwrite_recv(struct tevent_req *req, int *err)
 794 {
 795         struct aio_fork_pwrite_state *state = tevent_req_data(
 796                 req, struct aio_fork_pwrite_state);
 797
 798         if (tevent_req_is_unix_error(req, err)) {
 799                 return -1;
 800         }
 801         if (state->ret == -1) {
 802                 *err = state->err;
 803         }
 804         return state->ret;
 805 }
 806
 807 struct aio_fork_fsync_state {
 808         struct aio_child *child;
 809         ssize_t ret;
 810         int err;
 811 };
 812
 813 static void aio_fork_fsync_done(struct tevent_req *subreq);
 814
 815 static struct tevent_req *aio_fork_fsync_send(
 816         struct vfs_handle_struct *handle, TALLOC_CTX *mem_ctx,
 817         struct tevent_context *ev, struct files_struct *fsp)
 818 {
 819         struct tevent_req *req, *subreq;
 820         struct aio_fork_fsync_state *state;
 821         struct rw_cmd cmd;
 822         ssize_t written;
 823         int err;
 824         struct aio_fork_config *config;
 825
 826         SMB_VFS_HANDLE_GET_DATA(handle, config,
 827                                 struct aio_fork_config,
 828                                 return NULL);
 829
 830         req = tevent_req_create(mem_ctx, &state, struct aio_fork_fsync_state);
 831         if (req == NULL) {
 832                 return NULL;
 833         }
 834
 835         err = get_idle_child(handle, &state->child);
 836         if (err != 0) {
 837                 tevent_req_error(req, err);
 838                 return tevent_req_post(req, ev);
 839         }
 840
 841         ZERO_STRUCT(cmd);
 842         cmd.cmd = FSYNC_CMD;
 843         cmd.erratic_testing_mode = config->erratic_testing_mode;
 844
 845         DEBUG(10, ("sending fd %d to child %d\n", fsp->fh->fd,
 846                    (int)state->child->pid));
 847
 848         /*
 849          * Not making this async. We're writing into an empty unix
 850          * domain socket. This should never block.
 851          */
 852         written = write_fd(state->child->sockfd, &cmd, sizeof(cmd),
 853                            fsp->fh->fd);
 854         if (written == -1) {
 855                 err = errno;
 856
 857                 TALLOC_FREE(state->child);
 858
 859                 DEBUG(10, ("write_fd failed: %s\n", strerror(err)));
 860                 tevent_req_error(req, err);
 861                 return tevent_req_post(req, ev);
 862         }
 863
 864         subreq = read_packet_send(state, ev, state->child->sockfd,
 865                                   sizeof(struct rw_ret), NULL, NULL);
 866         if (tevent_req_nomem(subreq, req)) {
 867                 TALLOC_FREE(state->child); /* we sent sth down */
 868                 return tevent_req_post(req, ev);
 869         }
 870         tevent_req_set_callback(subreq, aio_fork_fsync_done, req);
 871         return req;
 872 }
 873
 874 static void aio_fork_fsync_done(struct tevent_req *subreq)
 875 {
 876         struct tevent_req *req = tevent_req_callback_data(
 877                 subreq, struct tevent_req);
 878         struct aio_fork_fsync_state *state = tevent_req_data(
 879                 req, struct aio_fork_fsync_state);
 880         ssize_t nread;
 881         uint8_t *buf;
 882         int err;
 883         struct rw_ret *retbuf;
 884
 885         nread = read_packet_recv(subreq, talloc_tos(), &buf, &err);
 886         TALLOC_FREE(subreq);
 887         if (nread == -1) {
 888                 TALLOC_FREE(state->child);
 889                 tevent_req_error(req, err);
 890                 return;
 891         }
 892
 893         state->child->busy = false;
 894
 895         retbuf = (struct rw_ret *)buf;
 896         state->ret = retbuf->size;
 897         state->err = retbuf->ret_errno;
 898         tevent_req_done(req);
 899 }
 900
 901 static int aio_fork_fsync_recv(struct tevent_req *req, int *err)
 902 {
 903         struct aio_fork_fsync_state *state = tevent_req_data(
 904                 req, struct aio_fork_fsync_state);
 905
 906         if (tevent_req_is_unix_error(req, err)) {
 907                 return -1;
 908         }
 909         if (state->ret == -1) {
 910                 *err = state->err;
 911         }
 912         return state->ret;
 913 }
 914
 915 static int aio_fork_connect(vfs_handle_struct *handle, const char *service,
 916                             const char *user)
 917 {
 918         int ret;
 919         struct aio_fork_config *config;
 920         ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 921
 922         if (ret < 0) {
 923                 return ret;
 924         }
 925
 926         config = talloc_zero(handle->conn, struct aio_fork_config);
 927         if (!config) {
 928                 SMB_VFS_NEXT_DISCONNECT(handle);
 929                 DEBUG(0, ("talloc_zero() failed\n"));
 930                 return -1;
 931         }
 932
 933         config->erratic_testing_mode = lp_parm_bool(SNUM(handle->conn), "vfs_aio_fork",
 934                                                     "erratic_testing_mode", false);
 935
 936         SMB_VFS_HANDLE_SET_DATA(handle, config,
 937                                 NULL, struct aio_fork_config,
 938                                 return -1);
 939
 940         /*********************************************************************
 941          * How many threads to initialize ?
 942          * 100 per process seems insane as a default until you realize that
 943          * (a) Threads terminate after 1 second when idle.
 944          * (b) Throttling is done in SMB2 via the crediting algorithm.
 945          * (c) SMB1 clients are limited to max_mux (50) outstanding
 946          *     requests and Windows clients don't use this anyway.
 947          * Essentially we want this to be unlimited unless smb.conf
 948          * says different.
 949          *********************************************************************/
 950         aio_pending_size = 100;
 951         return 0;
 952 }
 953
 954 static struct vfs_fn_pointers vfs_aio_fork_fns = {
 955         .connect_fn = aio_fork_connect,
 956         .pread_send_fn = aio_fork_pread_send,
 957         .pread_recv_fn = aio_fork_pread_recv,
 958         .pwrite_send_fn = aio_fork_pwrite_send,
 959         .pwrite_recv_fn = aio_fork_pwrite_recv,
 960         .fsync_send_fn = aio_fork_fsync_send,
 961         .fsync_recv_fn = aio_fork_fsync_recv,
 962 };
 963
 964 NTSTATUS vfs_aio_fork_init(void);
 965 NTSTATUS vfs_aio_fork_init(void)
 966 {
 967         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 968                                 "aio_fork", &vfs_aio_fork_fns);
 969 }