root/source3/modules/onefs_notify.c

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DEFINITIONS

This source file includes following definitions.
  1. onefs_notify_smb_filter_to_ifs_filter
  2. onefs_notify_ifs_filter_to_smb_action
  3. get_ifs_event_path
  4. onefs_notify_dispatch
  5. onefs_notify_handler
  6. onefs_watch_destructor
  7. onefs_notify_watch

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  *
   4  * Support for change notify using OneFS's file event notification system
   5  *
   6  * Copyright (C) Andrew Tridgell, 2006
   7  * Copyright (C) Steven Danneman, 2008
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  21  */
  22 
  23 /* Implement handling of change notify requests on files and directories using
  24  * Isilon OneFS's "ifs event" file notification system.
  25  *
  26  * The structure of this file is based off the implementation of change notify
  27  * using the inotify system calls in smbd/notify_inotify.c */
  28 
  29 /* TODO: We could reduce the number of file descriptors used by merging
  30  * multiple watch requests on the same directory into the same
  31  * onefs_notify_watch_context.  To do this we'd need mux/demux routines that
  32  * when receiving an event on that watch context would check it against the
  33  * CompletionFilter and WatchTree of open SMB requests, and return notify
  34  * events back to the proper SMB requests */
  35 
  36 #include "includes.h"
  37 #include "onefs.h"
  38 
  39 #include <ifs/ifs_types.h>
  40 #include <ifs/ifs_syscalls.h>
  41 #include <isi_util/syscalls.h>
  42 
  43 #include <sys/event.h>
  44 
  45 #define ONEFS_IFS_EVENT_MAX_NUM 8
  46 #define ONEFS_IFS_EVENT_MAX_BYTES (ONEFS_IFS_EVENT_MAX_NUM * \
  47                                    sizeof(struct ifs_event))
  48 
  49 struct onefs_notify_watch_context {
  50         struct sys_notify_context *ctx;
  51         int watch_fd;
  52         ino_t watch_lin;
  53         const char *path;
  54         int ifs_event_fd;
  55         uint32_t ifs_filter; /* the ifs event mask */
  56         uint32_t smb_filter; /* the windows completion filter */
  57         void (*callback)(struct sys_notify_context *ctx,
  58                          void *private_data,
  59                          struct notify_event *ev);
  60         void *private_data;
  61 };
  62 
  63 /**
  64  * Conversion map from a SMB completion filter to an IFS event mask.
  65  */
  66 static const struct {
  67         uint32_t smb_filter;
  68         uint32_t ifs_filter;
  69 } onefs_notify_conv[] = {
  70         {FILE_NOTIFY_CHANGE_FILE_NAME,
  71             NOTE_CREATE | NOTE_DELETE | NOTE_RENAME_FROM | NOTE_RENAME_TO},
  72         {FILE_NOTIFY_CHANGE_DIR_NAME,
  73             NOTE_CREATE | NOTE_DELETE | NOTE_RENAME_FROM | NOTE_RENAME_TO},
  74         {FILE_NOTIFY_CHANGE_ATTRIBUTES,
  75             NOTE_CREATE | NOTE_DELETE | NOTE_RENAME_FROM | NOTE_RENAME_TO |
  76             NOTE_ATTRIB},
  77         {FILE_NOTIFY_CHANGE_SIZE,
  78             NOTE_SIZE | NOTE_EXTEND},
  79         {FILE_NOTIFY_CHANGE_LAST_WRITE,
  80             NOTE_WRITE | NOTE_ATTRIB},
  81         /* OneFS doesn't set atime by default, but we can somewhat fake it by
  82          * notifying for other events that imply ACCESS */
  83         {FILE_NOTIFY_CHANGE_LAST_ACCESS,
  84             NOTE_WRITE | NOTE_ATTRIB},
  85         /* We don't have an ifs_event for the setting of create time, but we
  86          * can fake by notifying when a "new" file is created via rename */
  87         {FILE_NOTIFY_CHANGE_CREATION,
  88             NOTE_RENAME_TO},
  89         {FILE_NOTIFY_CHANGE_SECURITY,
  90             NOTE_SECURITY},
  91         /* Unsupported bits
  92         FILE_NOTIFY_CHANGE_EA            (no EAs in OneFS)
  93         FILE_NOTIFY_CHANGE_STREAM_NAME   (no ifs_event equivalent)
  94         FILE_NOTIFY_CHANGE_STREAM_SIZE   (no ifs_event equivalent)
  95         FILE_NOTIFY_CHANGE_STREAM_WRITE  (no ifs_event equivalent) */
  96 };
  97 
  98 #define ONEFS_NOTIFY_UNSUPPORTED  (FILE_NOTIFY_CHANGE_LAST_ACCESS | \
  99                                    FILE_NOTIFY_CHANGE_CREATION    | \
 100                                    FILE_NOTIFY_CHANGE_EA          | \
 101                                    FILE_NOTIFY_CHANGE_STREAM_NAME | \
 102                                    FILE_NOTIFY_CHANGE_STREAM_SIZE | \
 103                                    FILE_NOTIFY_CHANGE_STREAM_WRITE)
 104 
 105 /**
 106  * Convert Windows/SMB filter/flags to IFS event filter.
 107  *
 108  * @param[in] smb_filter Windows Completion Filter sent in the SMB
 109  *
 110  * @return ifs event filter mask
 111  */
 112 static uint32_t
 113 onefs_notify_smb_filter_to_ifs_filter(uint32_t smb_filter)
     /* [<][>][^][v][top][bottom][index][help] */
 114 {
 115         int i;
 116         uint32_t ifs_filter = 0x0;
 117 
 118         for (i=0;i<ARRAY_SIZE(onefs_notify_conv);i++) {
 119                 if (onefs_notify_conv[i].smb_filter & smb_filter) {
 120                         ifs_filter |= onefs_notify_conv[i].ifs_filter;
 121                 }
 122         }
 123 
 124         return ifs_filter;
 125 }
 126 
 127 /**
 128  * Convert IFS filter/flags to a Windows notify action.
 129  *
 130  * Returns Win notification actions, types (1-5).
 131  *
 132  * @param[in] smb_filter Windows Completion Filter sent in the SMB
 133  * @param[in] ifs_filter Returned from the kernel in the ifs_event
 134  *
 135  * @return 0 if there are no more relevant flags.
 136  */
 137 static int
 138 onefs_notify_ifs_filter_to_smb_action(uint32_t smb_filter, uint32_t ifs_filter)
     /* [<][>][^][v][top][bottom][index][help] */
 139 {
 140         /* Handle Windows special cases, before modifying events bitmask */
 141 
 142         /* Special case 1: win32api->MoveFile needs to send a modified
 143          * notification on the new file, if smb_filter == ATTRIBUTES.
 144          * Here we handle the case where two separate ATTR & NAME notifications
 145          * have been registered.  We handle the case where both bits are set in
 146          * the same registration in onefs_notify_dispatch() */
 147         if ((smb_filter & FILE_NOTIFY_CHANGE_ATTRIBUTES) &&
 148                 !(smb_filter & FILE_NOTIFY_CHANGE_FILE_NAME) &&
 149                 (ifs_filter & NOTE_FILE) && (ifs_filter & NOTE_RENAME_TO))
 150         {
 151                 return NOTIFY_ACTION_MODIFIED;
 152         }
 153 
 154         /* Special case 2: Writes need to send a modified
 155          * notification on the file, if smb_filter = ATTRIBUTES. */
 156         if ((smb_filter & FILE_NOTIFY_CHANGE_ATTRIBUTES) &&
 157                 (ifs_filter & NOTE_FILE) && (ifs_filter & NOTE_WRITE))
 158         {
 159                 return NOTIFY_ACTION_MODIFIED;
 160         }
 161 
 162         /* Loop because some events may be filtered out. Eventually all
 163          * relevant events will be taken care of and returned. */
 164         while (1) {
 165                 if (ifs_filter & NOTE_CREATE) {
 166                         ifs_filter &= ~NOTE_CREATE;
 167                         if ((smb_filter & FILE_NOTIFY_CHANGE_FILE_NAME) &&
 168                                 (ifs_filter & NOTE_FILE))
 169                                 return NOTIFY_ACTION_ADDED;
 170                         if ((smb_filter & FILE_NOTIFY_CHANGE_DIR_NAME) &&
 171                                 (ifs_filter & NOTE_DIRECTORY))
 172                                 return NOTIFY_ACTION_ADDED;
 173                 }
 174                 else if (ifs_filter & NOTE_DELETE) {
 175                         ifs_filter &= ~NOTE_DELETE;
 176                         if ((smb_filter & FILE_NOTIFY_CHANGE_FILE_NAME) &&
 177                                 (ifs_filter & NOTE_FILE))
 178                                 return NOTIFY_ACTION_REMOVED;
 179                         if ((smb_filter & FILE_NOTIFY_CHANGE_DIR_NAME) &&
 180                                 (ifs_filter & NOTE_DIRECTORY))
 181                                 return NOTIFY_ACTION_REMOVED;
 182                 }
 183                 else if (ifs_filter & NOTE_WRITE) {
 184                         ifs_filter &= ~NOTE_WRITE;
 185                         if ((smb_filter & FILE_NOTIFY_CHANGE_LAST_WRITE) ||
 186                                 (smb_filter & FILE_NOTIFY_CHANGE_LAST_ACCESS))
 187                                 return NOTIFY_ACTION_MODIFIED;
 188                 }
 189                 else if ((ifs_filter & NOTE_SIZE) || (ifs_filter & NOTE_EXTEND)) {
 190                         ifs_filter &= ~NOTE_SIZE;
 191                         ifs_filter &= ~NOTE_EXTEND;
 192 
 193                         /* TODO: Do something on NOTE_DIR? */
 194                         if ((smb_filter & FILE_NOTIFY_CHANGE_SIZE) &&
 195                             (ifs_filter & NOTE_FILE))
 196                                 return NOTIFY_ACTION_MODIFIED;
 197                 }
 198                 else if (ifs_filter & NOTE_ATTRIB) {
 199                         ifs_filter &= ~NOTE_ATTRIB;
 200                         /* NOTE_ATTRIB needs to be converted to a
 201                          * LAST_WRITE as well, because we need to send
 202                          * LAST_WRITE when the mtime changes. Looking into
 203                          * better alternatives as this causes extra LAST_WRITE
 204                          * notifications. We also return LAST_ACCESS as a
 205                          * modification to attribs implies this. */
 206                         if ((smb_filter & FILE_NOTIFY_CHANGE_ATTRIBUTES) ||
 207                                 (smb_filter & FILE_NOTIFY_CHANGE_LAST_WRITE) ||
 208                                 (smb_filter & FILE_NOTIFY_CHANGE_LAST_ACCESS))
 209                                 return NOTIFY_ACTION_MODIFIED;
 210                 }
 211                 else if (ifs_filter & NOTE_LINK) {
 212                         ifs_filter &= ~NOTE_LINK;
 213                         /* NOTE_LINK will send out NO notifications */
 214                 }
 215                 else if (ifs_filter & NOTE_REVOKE) {
 216                         ifs_filter &= ~NOTE_REVOKE;
 217                         /* NOTE_REVOKE will send out NO notifications */
 218                 }
 219                 else if (ifs_filter & NOTE_RENAME_FROM)  {
 220                         ifs_filter &= ~NOTE_RENAME_FROM;
 221 
 222                         if (((smb_filter & FILE_NOTIFY_CHANGE_FILE_NAME) &&
 223                                  (ifs_filter & NOTE_FILE)) ||
 224                                 ((smb_filter & FILE_NOTIFY_CHANGE_DIR_NAME) &&
 225                                  (ifs_filter & NOTE_DIRECTORY))) {
 226                                 /* Check if this is a RENAME, not a MOVE */
 227                                 if (ifs_filter & NOTE_RENAME_SAMEDIR) {
 228                                         /* Remove the NOTE_RENAME_SAMEDIR, IFF
 229                                          * RENAME_TO is not in this event */
 230                                         if (!(ifs_filter & NOTE_RENAME_TO))
 231                                                 ifs_filter &=
 232                                                     ~NOTE_RENAME_SAMEDIR;
 233                                         return NOTIFY_ACTION_OLD_NAME;
 234                                 }
 235                                 return NOTIFY_ACTION_REMOVED;
 236                         }
 237                 }
 238                 else if (ifs_filter & NOTE_RENAME_TO) {
 239                         ifs_filter &= ~NOTE_RENAME_TO;
 240 
 241                         if (((smb_filter & FILE_NOTIFY_CHANGE_FILE_NAME) &&
 242                                  (ifs_filter & NOTE_FILE)) ||
 243                                 ((smb_filter & FILE_NOTIFY_CHANGE_DIR_NAME) &&
 244                                  (ifs_filter & NOTE_DIRECTORY))) {
 245                                 /* Check if this is a RENAME, not a MOVE */
 246                                 if (ifs_filter & NOTE_RENAME_SAMEDIR) {
 247                                         /* Remove the NOTE_RENAME_SAMEDIR, IFF
 248                                          * RENAME_FROM is not in this event */
 249                                         if (!(ifs_filter & NOTE_RENAME_FROM))
 250                                                 ifs_filter &=
 251                                                     ~NOTE_RENAME_SAMEDIR;
 252                                         return NOTIFY_ACTION_NEW_NAME;
 253                                 }
 254                                 return NOTIFY_ACTION_ADDED;
 255                         }
 256                         /* RAW-NOTIFY shows us that a rename triggers a
 257                          * creation time change */
 258                         if ((smb_filter & FILE_NOTIFY_CHANGE_CREATION) &&
 259                                 (ifs_filter & NOTE_FILE))
 260                                 return NOTIFY_ACTION_MODIFIED;
 261                 }
 262                 else if (ifs_filter & NOTE_SECURITY) {
 263                         ifs_filter &= ~NOTE_SECURITY;
 264 
 265                         if (smb_filter & FILE_NOTIFY_CHANGE_SECURITY)
 266                                 return NOTIFY_ACTION_MODIFIED;
 267                 } else {
 268                         /* No relevant flags found */
 269                         return 0;
 270                 }
 271         }
 272 }
 273 
 274 /**
 275  * Retrieve a directory path of a changed file, relative to the watched dir
 276  *
 277  * @param[in] wc watch context for the returned event
 278  * @param[in] e ifs_event notification returned from the kernel
 279  * @param[out] path name relative to the watched dir. This is talloced
 280  *                  off of wc and needs to be freed by the caller.
 281  *
 282  * @return true on success
 283  *
 284  * TODO: This function currently doesn't handle path names with multiple
 285  * encodings.  enc_get_lin_path() should be used in the future to convert
 286  * each path segment's encoding to UTF-8
 287  */
 288 static bool
 289 get_ifs_event_path(struct onefs_notify_watch_context *wc, struct ifs_event *e,
     /* [<][>][^][v][top][bottom][index][help] */
 290                    char **path)
 291 {
 292         char *path_buf = NULL;
 293         size_t pathlen = 0;
 294         int error = 0;
 295 
 296         SMB_ASSERT(path);
 297 
 298         /* Lookup the path from watch_dir through our parent dir */
 299         if (e->namelen > 0) {
 300                 error = lin_get_path(wc->watch_lin,
 301                                      e->parent_lin,
 302                                      HEAD_SNAPID,
 303                                      e->parent_parent_lin,
 304                                      e->parent_name_hash,
 305                                      &pathlen, &path_buf);
 306                 if (!error) {
 307                         /* Only add slash if a path exists in path_buf from
 308                          * lin_get_path call. Windows does not expect a
 309                          * leading '/' */
 310                         if (pathlen > 0)
 311                                 *path = talloc_asprintf(wc, "%s/%s",
 312                                                         path_buf, e->name);
 313                         else
 314                                 *path = talloc_asprintf(wc, "%s", e->name);
 315                         SAFE_FREE(path_buf);
 316                 }
 317         }
 318 
 319         /* If ifs_event didn't return a name, or we errored out of our intial
 320          * path lookup, try again using the lin of the changed file */
 321         if (!(*path)) {
 322                 error = lin_get_path(wc->watch_lin,
 323                                      e->lin,
 324                                      HEAD_SNAPID,
 325                                      e->parent_lin,
 326                                      e->name_hash,
 327                                      &pathlen, &path_buf);
 328                 if (error) {
 329                         /* It's possible that both the lin and the parent lin
 330                          * are invalid (or not given) -- we will skip these
 331                          * events. */
 332                         DEBUG(3,("Path lookup failed. LINS are invalid: "
 333                                  "e->lin: 0x%llu, e->parent_lin: 0x%llu, "
 334                                  "e->parent_parent_lin: 0x%llu\n",
 335                                  e->lin, e->parent_lin, e->parent_parent_lin));
 336                         SAFE_FREE(path_buf);
 337                         return false;
 338                 } else {
 339                         *path = talloc_asprintf(wc, "%s", path_buf);
 340                         DEBUG(5, ("Using path from event LIN = %s\n",
 341                             path_buf));
 342                         SAFE_FREE(path_buf);
 343                 }
 344         }
 345 
 346         /* Replacement of UNIX slashes with WIN slashes is handled at a
 347          * higher layer. */
 348 
 349         return true;
 350 }
 351 
 352 /**
 353  * Dispatch one OneFS notify event to the general Samba code
 354  *
 355  * @param[in] wc watch context for the returned event
 356  * @param[in] e event returned from the kernel
 357  *
 358  * @return nothing
 359  */
 360 static void
 361 onefs_notify_dispatch(struct onefs_notify_watch_context *wc,
     /* [<][>][^][v][top][bottom][index][help] */
 362                       struct ifs_event *e)
 363 {
 364         char *path = NULL;
 365         struct notify_event ne;
 366 
 367         DEBUG(5, ("Retrieved ifs event from kernel: lin=%#llx, ifs_events=%#x, "
 368                  "parent_lin=%#llx, namelen=%d, name=\"%s\"\n",
 369                  e->lin, e->events, e->parent_lin, e->namelen, e->name));
 370 
 371         /* Check validity of event returned from kernel */
 372         if (e->lin == 0) {
 373                 /* The lin == 0 specifies 1 of 2 cases:
 374                  * 1) We are out of events. The kernel has a limited
 375                  *    amount (somewhere near 90000)
 376                  * 2) Split nodes have merged back and had data written
 377                  *    to them -- thus we've missed some of those events.  */
 378                 DEBUG(3, ("We've missed some kernel ifs events!\n"));
 379 
 380                 /* Alert higher level to the problem so it returns catch-all
 381                  * response to the client */
 382                 ne.path = NULL;
 383                 ne.action = 0;
 384                 wc->callback(wc->ctx, wc->private_data, &ne);
 385         }
 386 
 387         if (e->lin == wc->watch_lin) {
 388                 /* Windows doesn't report notifications on root
 389                  * watched directory */
 390                 /* TODO: This should be abstracted out to the general layer
 391                  * instead of being handled in every notify provider */
 392                 DEBUG(5, ("Skipping notification on root of the watched "
 393                          "path.\n"));
 394                 return;
 395         }
 396 
 397         /* Retrieve the full path for the ifs event name */
 398         if(!get_ifs_event_path(wc, e, &path)) {
 399                 DEBUG(3, ("Failed to convert the ifs_event lins to a path. "
 400                          "Skipping this event\n"));
 401                 return;
 402         }
 403 
 404         if (!strncmp(path, ".ifsvar", 7)) {
 405                 /* Skip notifications on file if its in ifs configuration
 406                  * directory */
 407                 goto clean;
 408         }
 409 
 410         ne.path = path;
 411 
 412         /* Convert ifs event mask to an smb action mask */
 413         ne.action = onefs_notify_ifs_filter_to_smb_action(wc->smb_filter,
 414                                                           e->events);
 415 
 416         DEBUG(5, ("Converted smb_filter=%#x, ifs_events=%#x, to "
 417                   "ne.action = %d, for ne.path = %s\n",
 418                   wc->smb_filter, e->events, ne.action, ne.path));
 419 
 420         if (!ne.action)
 421                 goto clean;
 422 
 423         /* Return notify_event to higher level */
 424         wc->callback(wc->ctx, wc->private_data, &ne);
 425 
 426         /* SMB expects a file rename/move to generate three actions, a
 427          * rename_from/delete on the from file, a rename_to/create on the to
 428          * file, and a modify for the rename_to file. If we have two separate
 429          * notifications registered for ATTRIBUTES and FILENAME, this case will
 430          * be handled by separate ifs_events in
 431          * onefs_notify_ifs_filter_to_smb_action(). If both bits are registered
 432          * in the same notification, we must send an extra MODIFIED action
 433          * here. */
 434         if ((wc->smb_filter & FILE_NOTIFY_CHANGE_ATTRIBUTES) &&
 435             (wc->smb_filter & FILE_NOTIFY_CHANGE_FILE_NAME) &&
 436             (e->events & NOTE_FILE) && (e->events & NOTE_RENAME_TO))
 437         {
 438                 ne.action = NOTIFY_ACTION_MODIFIED;
 439                 wc->callback(wc->ctx, wc->private_data, &ne);
 440         }
 441 
 442         /* FALLTHROUGH */
 443 clean:
 444         talloc_free(path);
 445         return;
 446 }
 447 
 448 /**
 449  * Callback when the kernel has some events for us
 450  *
 451  * Read events off ifs event fd and pass them to our dispatch function
 452  *
 453  * @param ev context of all tevents registered in the smbd
 454  * @param fde tevent struct specific to one ifs event channel
 455  * @param flags tevent flags passed when we added our ifs event channel fd to
 456  *              the main loop
 457  * @param private_data onefs_notify_watch_context specific to this ifs event
 458  *                     channel
 459  *
 460  * @return nothing
 461  */
 462 static void
 463 onefs_notify_handler(struct event_context *ev,
     /* [<][>][^][v][top][bottom][index][help] */
 464                      struct fd_event *fde,
 465                      uint16_t flags,
 466                      void *private_data)
 467 {
 468         struct onefs_notify_watch_context *wc = NULL;
 469         struct ifs_event ifs_events[ONEFS_IFS_EVENT_MAX_NUM];
 470         ssize_t nread = 0;
 471         int count = 0;
 472         int i = 0;
 473 
 474         wc = talloc_get_type(private_data, struct onefs_notify_watch_context);
 475 
 476         /* Read as many ifs events from the notify channel as we can */
 477         nread = sys_read(wc->ifs_event_fd, &ifs_events,
 478                          ONEFS_IFS_EVENT_MAX_BYTES);
 479         if (nread == 0) {
 480                 DEBUG(0,("No data found while reading ifs event fd?!\n"));
 481                 return;
 482         }
 483         if (nread < 0) {
 484                 DEBUG(0,("Failed to read ifs event data: %s\n",
 485                         strerror(errno)));
 486                 return;
 487         }
 488 
 489         count = nread / sizeof(struct ifs_event);
 490 
 491         DEBUG(5, ("Got %d notification events in %d bytes.\n", count, nread));
 492 
 493         /* Dispatch ifs_events one-at-a-time to higher level */
 494         for (i=0; i < count; i++) {
 495                 onefs_notify_dispatch(wc, &ifs_events[i]);
 496         }
 497 }
 498 
 499 /**
 500  * Destroy the ifs event channel
 501  *
 502  * This is called from talloc_free() when the generic Samba notify layer frees
 503  * the onefs_notify_watch_context.
 504  *
 505  * @param[in] wc pointer to watch context which is being destroyed
 506  *
 507  * return 0 on success
 508 */
 509 static int
 510 onefs_watch_destructor(struct onefs_notify_watch_context *wc)
     /* [<][>][^][v][top][bottom][index][help] */
 511 {
 512         /* The ifs_event_fd will re de-registered from the event loop by
 513          * another destructor triggered from the freeing of this wc */
 514         close(wc->ifs_event_fd);
 515         return 0;
 516 }
 517 
 518 /**
 519  * Register a single change notify watch request.
 520  *
 521  * Open an event listener on a directory to watch for modifications. This
 522  * channel is closed by a destructor when the caller calls talloc_free()
 523  * on *handle.
 524  *
 525  * @param[in] vfs_handle handle given to most VFS operations
 526  * @param[in] ctx context (conn and tevent) for this connection
 527  * @param[in] e filter and path of client's notify request
 528  * @param[in] callback function to call when file notification event is received
 529  *                     from the kernel, passing that event up to Samba's
 530  *                     generalized change notify layer
 531  * @param[in] private_data opaque data given to us by the general change notify
 532  *                         layer which must be returned in the callback function
 533  * @param[out] handle_p handle returned to generalized change notify layer used
 534  *                      to close the event channel when notification is
 535  *                      cancelled
 536  *
 537  * @return NT_STATUS_OK unless error
 538  */
 539 NTSTATUS
 540 onefs_notify_watch(vfs_handle_struct *vfs_handle,
     /* [<][>][^][v][top][bottom][index][help] */
 541                    struct sys_notify_context *ctx,
 542                    struct notify_entry *e,
 543                    void (*callback)(struct sys_notify_context *ctx,
 544                                     void *private_data,
 545                                     struct notify_event *ev),
 546                    void *private_data,
 547                    void *handle_p)
 548 {
 549         int ifs_event_fd = -1;
 550         uint32_t ifs_filter = 0;
 551         uint32_t smb_filter = e->filter;
 552         bool watch_tree = !!e->subdir_filter;
 553         struct onefs_notify_watch_context *wc = NULL;
 554         void **handle = (void **)handle_p;
 555         SMB_STRUCT_STAT sbuf;
 556         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
 557 
 558         /* Fallback to default Samba implementation if kernel CN is disabled */
 559         if (!lp_kernel_change_notify(vfs_handle->conn->params)) {
 560                 (*handle) = NULL;
 561                 return NT_STATUS_OK;
 562         }
 563 
 564         /* The OneFS open path should always give us a valid fd on a directory*/
 565         SMB_ASSERT(e->dir_fd >= 0);
 566 
 567         /* Always set e->filter to 0 so we don't fallback on the default change
 568          * notify backend. It's not cluster coherent or cross-protocol so we
 569          * can't guarantee correctness using it. */
 570         e->filter = 0;
 571         e->subdir_filter = 0;
 572 
 573         /* Snapshots do not currently allow event listeners. See Isilon
 574          * bug 33476 for an example of .snapshot debug spew that can occur. */
 575         if (e->dir_id.extid != HEAD_SNAPID)
 576                 return NT_STATUS_INVALID_PARAMETER;
 577 
 578         /* Convert Completion Filter mask to IFS Event mask */
 579         ifs_filter = onefs_notify_smb_filter_to_ifs_filter(smb_filter);
 580 
 581         if (smb_filter & ONEFS_NOTIFY_UNSUPPORTED) {
 582                 /* One or more of the filter bits could not be fully handled by
 583                  * the ifs_event system. To be correct, if we cannot service a
 584                  * bit in the completion filter we should return
 585                  * NT_STATUS_NOT_IMPLEMENTED to let the client know that they
 586                  * won't be receiving all the notify events that they asked for.
 587                  * Unfortunately, WinXP clients cache this error message, stop
 588                  * trying to send any notify requests at all, and instead return
 589                  * NOT_IMPLEMENTED to all requesting apps without ever sending a
 590                  * message to us. Thus we lie, and say we can service all bits,
 591                  * but simply don't return actions for the filter bits we can't
 592                  * detect or fully implement. */
 593                 DEBUG(3,("One or more of the Windows completion filter bits "
 594                          "for \"%s\" could not be fully handled by the "
 595                          "ifs_event system. The failed bits are "
 596                          "smb_filter=%#x\n",
 597                          e->path, smb_filter & ONEFS_NOTIFY_UNSUPPORTED));
 598         }
 599 
 600         if (ifs_filter == 0) {
 601                 /* None of the filter bits given are supported by the ifs_event
 602                  * system. Don't create a kernel notify channel, but mock
 603                  * up a fake handle for the caller. */
 604                 DEBUG(3,("No bits in the Windows completion filter could be "
 605                          "translated to ifs_event mask for \"%s\", "
 606                          "smb_filter=%#x\n", e->path, smb_filter));
 607                 (*handle) = NULL;
 608                 return NT_STATUS_OK;
 609         }
 610 
 611         /* Register an ifs event channel for this watch request */
 612         ifs_event_fd = ifs_create_listener(watch_tree ?
 613                                            EVENT_RECURSIVE :
 614                                            EVENT_CHILDREN,
 615                                            ifs_filter,
 616                                            e->dir_fd);
 617         if (ifs_event_fd < 0) {
 618                 DEBUG(0,("Failed to create listener for %s with \"%s\". "
 619                         "smb_filter=0x%x, ifs_filter=0x%x, watch_tree=%u\n",
 620                         strerror(errno), e->path, smb_filter, ifs_filter,
 621                         watch_tree));
 622                 return map_nt_error_from_unix(errno);
 623         }
 624 
 625         /* Create a watch context to track this change notify request */
 626         wc = talloc(ctx, struct onefs_notify_watch_context);
 627         if (wc == NULL) {
 628                 status = NT_STATUS_NO_MEMORY;
 629                 goto err;
 630         }
 631 
 632         /* Get LIN for directory */
 633         if (sys_fstat(e->dir_fd, &sbuf)) {
 634                 DEBUG(0, ("stat on directory fd failed: %s\n",
 635                           strerror(errno)));
 636                 status = map_nt_error_from_unix(errno);
 637                 goto err;
 638         }
 639 
 640         if (sbuf.st_ino == 0) {
 641                 DEBUG(0, ("0 LIN found!\n"));
 642                 goto err;
 643         }
 644 
 645         wc->ctx = ctx;
 646         wc->watch_fd = e->dir_fd;
 647         wc->watch_lin = sbuf.st_ino;
 648         wc->ifs_event_fd = ifs_event_fd;
 649         wc->ifs_filter = ifs_filter;
 650         wc->smb_filter = smb_filter;
 651         wc->callback = callback;
 652         wc->private_data = private_data;
 653         wc->path = talloc_strdup(wc, e->path);
 654         if (wc->path == NULL) {
 655                 status = NT_STATUS_NO_MEMORY;
 656                 goto err;
 657         }
 658 
 659         (*handle) = wc;
 660 
 661         /* The caller frees the handle to stop watching */
 662         talloc_set_destructor(wc, onefs_watch_destructor);
 663 
 664         /* Add a tevent waiting for the ifs event fd to be readable */
 665         event_add_fd(ctx->ev, wc, wc->ifs_event_fd, EVENT_FD_READ,
 666                      onefs_notify_handler, wc);
 667 
 668         DEBUG(10, ("Watching for changes on \"%s\" smb_filter=0x%x, "
 669                    "ifs_filter=0x%x, watch_tree=%d, ifs_event_fd=%d, "
 670                    "dir_fd=%d, dir_lin=0x%llx\n",
 671                    e->path, smb_filter, ifs_filter, watch_tree,
 672                    ifs_event_fd, e->dir_fd, sbuf.st_ino));
 673 
 674         return NT_STATUS_OK;
 675 
 676 err:
 677         talloc_free(wc);
 678         SMB_ASSERT(ifs_event_fd >= 0);
 679         close(ifs_event_fd);
 680         return status;
 681 }

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