monitor.c

   1
   2 #include "mdadm.h"
   3 #include "mdmon.h"
   4
   5 #include <sys/select.h>
   6 #include <signal.h>
   7
   8 static char *array_states[] = {
   9         "clear", "inactive", "suspended", "readonly", "read-auto",
  10         "clean", "active", "write-pending", "active-idle", NULL };
  11 static char *sync_actions[] = {
  12         "idle", "reshape", "resync", "recover", "check", "repair", NULL
  13 };
  14
  15 static int write_attr(char *attr, int fd)
  16 {
  17         return write(fd, attr, strlen(attr));
  18 }
  19
  20 static void add_fd(fd_set *fds, int *maxfd, int fd)
  21 {
  22         if (fd < 0)
  23                 return;
  24         if (fd > *maxfd)
  25                 *maxfd = fd;
  26         FD_SET(fd, fds);
  27 }
  28
  29 static int read_attr(char *buf, int len, int fd)
  30 {
  31         int n;
  32
  33         if (fd < 0) {
  34                 buf[0] = 0;
  35                 return 0;
  36         }
  37         lseek(fd, 0, 0);
  38         n = read(fd, buf, len - 1);
  39
  40         if (n <= 0) {
  41                 buf[0] = 0;
  42                 return 0;
  43         }
  44         buf[n] = 0;
  45         if (buf[n-1] == '\n')
  46                 buf[n-1] = 0;
  47         return n;
  48 }
  49
  50
  51 static int get_resync_start(struct active_array *a)
  52 {
  53         char buf[30];
  54         int n;
  55
  56         n = read_attr(buf, 30, a->resync_start_fd);
  57         if (n <= 0)
  58                 return n;
  59
  60         a->resync_start = strtoull(buf, NULL, 10);
  61
  62         return 1;
  63 }
  64
  65 static int attr_match(const char *attr, const char *str)
  66 {
  67         /* See if attr, read from a sysfs file, matches
  68          * str.  They must either be the same, or attr can
  69          * have a trailing newline or comma
  70          */
  71         while (*attr && *str && *attr == *str) {
  72                 attr++;
  73                 str++;
  74         }
  75
  76         if (*str || (*attr && *attr != ',' && *attr != '\n'))
  77                 return 0;
  78         return 1;
  79 }
  80
  81 static int match_word(const char *word, char **list)
  82 {
  83         int n;
  84         for (n=0; list[n]; n++)
  85                 if (attr_match(word, list[n]))
  86                         break;
  87         return n;
  88 }
  89
  90 static enum array_state read_state(int fd)
  91 {
  92         char buf[20];
  93         int n = read_attr(buf, 20, fd);
  94
  95         if (n <= 0)
  96                 return bad_word;
  97         return (enum array_state) match_word(buf, array_states);
  98 }
  99
 100 static enum sync_action read_action( int fd)
 101 {
 102         char buf[20];
 103         int n = read_attr(buf, 20, fd);
 104
 105         if (n <= 0)
 106                 return bad_action;
 107         return (enum sync_action) match_word(buf, sync_actions);
 108 }
 109
 110 int read_dev_state(int fd)
 111 {
 112         char buf[60];
 113         int n = read_attr(buf, 60, fd);
 114         char *cp;
 115         int rv = 0;
 116
 117         if (n <= 0)
 118                 return 0;
 119
 120         cp = buf;
 121         while (cp) {
 122                 if (attr_match(cp, "faulty"))
 123                         rv |= DS_FAULTY;
 124                 if (attr_match(cp, "in_sync"))
 125                         rv |= DS_INSYNC;
 126                 if (attr_match(cp, "write_mostly"))
 127                         rv |= DS_WRITE_MOSTLY;
 128                 if (attr_match(cp, "spare"))
 129                         rv |= DS_SPARE;
 130                 if (attr_match(cp, "blocked"))
 131                         rv |= DS_BLOCKED;
 132                 cp = strchr(cp, ',');
 133                 if (cp)
 134                         cp++;
 135         }
 136         return rv;
 137 }
 138
 139 static void signal_manager(void)
 140 {
 141         kill(getpid(), SIGUSR1);
 142 }
 143
 144 /* Monitor a set of active md arrays - all of which share the
 145  * same metadata - and respond to events that require
 146  * metadata update.
 147  *
 148  * New arrays are detected by another thread which allocates
 149  * required memory and attaches the data structure to our list.
 150  *
 151  * Events:
 152  *  Array stops.
 153  *    This is detected by array_state going to 'clear' or 'inactive'.
 154  *    while we thought it was active.
 155  *    Response is to mark metadata as clean and 'clear' the array(??)
 156  *  write-pending
 157  *    array_state if 'write-pending'
 158  *    We mark metadata as 'dirty' then set array to 'active'.
 159  *  active_idle
 160  *    Either ignore, or mark clean, then mark metadata as clean.
 161  *
 162  *  device fails
 163  *    detected by rd-N/state reporting "faulty"
 164  *    mark device as 'failed' in metadata, let the kernel release the
 165  *    device by writing '-blocked' to rd/state, and finally write 'remove' to
 166  *    rd/state.  Before a disk can be replaced it must be failed and removed
 167  *    from all container members, this will be preemptive for the other
 168  *    arrays... safe?
 169  *
 170  *  sync completes
 171  *    sync_action was 'resync' and becomes 'idle' and resync_start becomes
 172  *    MaxSector
 173  *    Notify metadata that sync is complete.
 174  *
 175  *  recovery completes
 176  *    sync_action changes from 'recover' to 'idle'
 177  *    Check each device state and mark metadata if 'faulty' or 'in_sync'.
 178  *
 179  *  deal with resync
 180  *    This only happens on finding a new array... mdadm will have set
 181  *    'resync_start' to the correct value.  If 'resync_start' indicates that an
 182  *    resync needs to occur set the array to the 'active' state rather than the
 183  *    initial read-auto state.
 184  *
 185  *
 186  *
 187  * We wait for a change (poll/select) on array_state, sync_action, and
 188  * each rd-X/state file.
 189  * When we get any change, we check everything.  So read each state file,
 190  * then decide what to do.
 191  *
 192  * The core action is to write new metadata to all devices in the array.
 193  * This is done at most once on any wakeup.
 194  * After that we might:
 195  *   - update the array_state
 196  *   - set the role of some devices.
 197  *   - request a sync_action
 198  *
 199  */
 200
 201 static int read_and_act(struct active_array *a)
 202 {
 203         int check_degraded = 0;
 204         int deactivate = 0;
 205         struct mdinfo *mdi;
 206
 207         a->next_state = bad_word;
 208         a->next_action = bad_action;
 209
 210         a->curr_state = read_state(a->info.state_fd);
 211         a->curr_action = read_action(a->action_fd);
 212         for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
 213                 mdi->next_state = 0;
 214                 if (mdi->state_fd >= 0)
 215                         mdi->curr_state = read_dev_state(mdi->state_fd);
 216         }
 217
 218         if (a->curr_state <= inactive &&
 219             a->prev_state > inactive) {
 220                 /* array has been stopped */
 221                 a->container->ss->set_array_state(a, 1);
 222                 a->next_state = clear;
 223                 deactivate = 1;
 224         }
 225         if (a->curr_state == write_pending) {
 226                 get_resync_start(a);
 227                 a->container->ss->set_array_state(a, 0);
 228                 a->next_state = active;
 229         }
 230         if (a->curr_state == active_idle) {
 231                 /* Set array to 'clean' FIRST, then
 232                  * a->ss->mark_clean(a, ~0ULL);
 233                  * just ignore for now.
 234                  */
 235         }
 236
 237         if (a->curr_state == readonly) {
 238                 /* Well, I'm ready to handle things, so
 239                  * read-auto is OK. FIXME what if we really want
 240                  * readonly ???
 241                  */
 242                 get_resync_start(a);
 243                 printf("Found a readonly array at %llu\n", a->resync_start);
 244                 if (a->resync_start == ~0ULL)
 245                         a->next_state = read_auto; /* array is clean */
 246                 else {
 247                         a->container->ss->set_array_state(a, 0);
 248                         a->next_state = active;
 249                 }
 250         }
 251
 252         if (a->curr_action == idle &&
 253             a->prev_action == resync) {
 254                 /* A resync has finished.  The endpoint is recorded in
 255                  * 'sync_start'.  We don't update the metadata
 256                  * until the array goes inactive or readonly though.
 257                  * Just check if we need to fiddle spares.
 258                  */
 259                 get_resync_start(a);
 260                 a->container->ss->set_array_state(a, 0);
 261                 check_degraded = 1;
 262         }
 263
 264         if (a->curr_action == idle &&
 265             a->prev_action == recover) {
 266                 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
 267                         a->container->ss->set_disk(a, mdi->disk.raid_disk,
 268                                                    mdi->curr_state);
 269                         if (! (mdi->curr_state & DS_INSYNC))
 270                                 check_degraded = 1;
 271                 }
 272         }
 273
 274         for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
 275                 if (mdi->curr_state & DS_FAULTY) {
 276                         a->container->ss->set_disk(a, mdi->disk.raid_disk,
 277                                                    mdi->curr_state);
 278                         check_degraded = 1;
 279                         mdi->next_state = DS_REMOVE;
 280                 }
 281         }
 282
 283         a->container->ss->sync_metadata(a->container);
 284
 285         /* Effect state changes in the array */
 286         if (a->next_state != bad_word)
 287                 write_attr(array_states[a->next_state], a->info.state_fd);
 288         if (a->next_action != bad_action)
 289                 write_attr(sync_actions[a->next_action], a->action_fd);
 290         for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
 291                 if (mdi->next_state == DS_REMOVE && mdi->state_fd >= 0) {
 292                         int remove_result;
 293
 294                         write_attr("-blocked", mdi->state_fd);
 295                         /* the kernel may not be able to immediately remove the
 296                          * disk, we can simply wait until the next event to try
 297                          * again.
 298                          */
 299                         remove_result = write_attr("remove", mdi->state_fd);
 300                         if (remove_result > 0) {
 301                                 close(mdi->state_fd);
 302                                 mdi->state_fd = -1;
 303                         }
 304                 }
 305                 if (mdi->next_state & DS_INSYNC)
 306                         write_attr("+in_sync", mdi->state_fd);
 307         }
 308
 309         /* move curr_ to prev_ */
 310         a->prev_state = a->curr_state;
 311
 312         a->prev_action = a->curr_action;
 313
 314         for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
 315                 mdi->prev_state = mdi->curr_state;
 316                 mdi->next_state = 0;
 317         }
 318
 319         if (check_degraded) {
 320                 /* manager will do the actual check */
 321                 a->check_degraded = 1;
 322                 signal_manager();
 323         }
 324
 325         if (deactivate)
 326                 a->container = NULL;
 327
 328         return 1;
 329 }
 330
 331 static struct mdinfo *
 332 find_device(struct active_array *a, int major, int minor)
 333 {
 334         struct mdinfo *mdi;
 335
 336         for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
 337                 if (mdi->disk.major == major && mdi->disk.minor == minor)
 338                         return mdi;
 339
 340         return NULL;
 341 }
 342
 343 static void reconcile_failed(struct active_array *aa, struct mdinfo *failed)
 344 {
 345         struct active_array *a;
 346         struct mdinfo *victim;
 347
 348         for (a = aa; a; a = a->next) {
 349                 if (!a->container)
 350                         continue;
 351                 victim = find_device(a, failed->disk.major, failed->disk.minor);
 352                 if (!victim)
 353                         continue;
 354
 355                 if (!(victim->curr_state & DS_FAULTY))
 356                         write_attr("faulty", victim->state_fd);
 357         }
 358 }
 359
 360 static int handle_remove_device(struct md_remove_device_cmd *cmd, struct active_array *aa)
 361 {
 362         struct active_array *a;
 363         struct mdinfo *victim;
 364         int rv;
 365
 366         /* scan all arrays for the given device, if ->state_fd is closed (-1)
 367          * in all cases then mark the disk as removed in the metadata.
 368          * Otherwise reply that it is busy.
 369          */
 370
 371         /* pass1 check that it is not in use anywhere */
 372         /* note: we are safe from re-adds as long as the device exists in the
 373          * container
 374          */
 375         for (a = aa; a; a = a->next) {
 376                 if (!a->container)
 377                         continue;
 378                 victim = find_device(a, major(cmd->rdev), minor(cmd->rdev));
 379                 if (!victim)
 380                         continue;
 381                 if (victim->state_fd > 0)
 382                         return -EBUSY;
 383         }
 384
 385         /* pass2 schedule and process removal per array */
 386         for (a = aa; a; a = a->next) {
 387                 if (!a->container)
 388                         continue;
 389                 victim = find_device(a, major(cmd->rdev), minor(cmd->rdev));
 390                 if (!victim)
 391                         continue;
 392                 victim->curr_state |= DS_REMOVE;
 393                 rv = read_and_act(a);
 394                 if (rv < 0)
 395                         return rv;
 396         }
 397
 398         return 0;
 399 }
 400
 401 static int handle_pipe(struct md_generic_cmd *cmd, struct active_array *aa)
 402 {
 403         switch (cmd->action) {
 404         case md_action_ping_monitor:
 405                 return 0;
 406         case md_action_remove_device:
 407                 return handle_remove_device((void *) cmd, aa);
 408         }
 409
 410         return -1;
 411 }
 412
 413 static int wait_and_act(struct supertype *container, int pfd,
 414                         int monfd, int nowait)
 415 {
 416         fd_set rfds;
 417         int maxfd = 0;
 418         struct active_array **aap = &container->arrays;
 419         struct active_array *a, **ap;
 420         int rv;
 421         struct mdinfo *mdi;
 422
 423         FD_ZERO(&rfds);
 424
 425         add_fd(&rfds, &maxfd, pfd);
 426         for (ap = aap ; *ap ;) {
 427                 a = *ap;
 428                 /* once an array has been deactivated we want to
 429                  * ask the manager to discard it.
 430                  */
 431                 if (!a->container) {
 432                         if (discard_this) {
 433                                 ap = &(*ap)->next;
 434                                 continue;
 435                         }
 436                         *ap = a->next;
 437                         a->next = NULL;
 438                         discard_this = a;
 439                         signal_manager();
 440                         continue;
 441                 }
 442
 443                 add_fd(&rfds, &maxfd, a->info.state_fd);
 444                 add_fd(&rfds, &maxfd, a->action_fd);
 445                 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
 446                         add_fd(&rfds, &maxfd, mdi->state_fd);
 447
 448                 ap = &(*ap)->next;
 449         }
 450
 451         if (manager_ready && *aap == NULL) {
 452                 /* No interesting arrays. Lets see about exiting.
 453                  * Note that blocking at this point is not a problem
 454                  * as there are no active arrays, there is nothing that
 455                  * we need to be ready to do.
 456                  */
 457                 int fd = open(container->device_name, O_RDONLY|O_EXCL);
 458                 if (fd >= 0 || errno != EBUSY) {
 459                         /* OK, we are safe to leave */
 460                         exit_now = 1;
 461                         signal_manager();
 462                         remove_pidfile(container->devname);
 463                         exit(0);
 464                 }
 465         }
 466
 467         if (!nowait) {
 468                 rv = select(maxfd+1, &rfds, NULL, NULL, NULL);
 469
 470                 if (rv <= 0)
 471                         return rv;
 472
 473                 if (FD_ISSET(pfd, &rfds)) {
 474                         int err = -1;
 475
 476                         if (read(pfd, &err, 1) > 0)
 477                                 err = handle_pipe(active_cmd, *aap);
 478                         write(monfd, &err, 1);
 479                 }
 480         }
 481
 482         if (update_queue) {
 483                 struct metadata_update *this;
 484
 485                 for (this = update_queue; this ; this = this->next)
 486                         container->ss->process_update(container, this);
 487
 488                 update_queue_handled = update_queue;
 489                 update_queue = NULL;
 490                 signal_manager();
 491                 container->ss->sync_metadata(container);
 492         }
 493
 494         for (a = *aap; a ; a = a->next) {
 495                 if (a->replaces && !discard_this) {
 496                         struct active_array **ap;
 497                         for (ap = &a->next; *ap && *ap != a->replaces;
 498                              ap = & (*ap)->next)
 499                                 ;
 500                         if (*ap)
 501                                 *ap = (*ap)->next;
 502                         discard_this = a->replaces;
 503                         a->replaces = NULL;
 504                         /* FIXME check if device->state_fd need to be cleared?*/
 505                         signal_manager();
 506                 }
 507                 if (a->container)
 508                         rv += read_and_act(a);
 509         }
 510
 511         /* propagate failures across container members */
 512         for (a = *aap; a ; a = a->next) {
 513                 if (!a->container)
 514                         continue;
 515                 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
 516                         if (mdi->curr_state & DS_FAULTY)
 517                                 reconcile_failed(*aap, mdi);
 518         }
 519
 520         return rv;
 521 }
 522
 523 void do_monitor(struct supertype *container)
 524 {
 525         int rv;
 526         int first = 1;
 527         do {
 528                 rv = wait_and_act(container, container->mgr_pipe[0],
 529                                   container->mon_pipe[1], first);
 530                 first = 0;
 531         } while (rv >= 0);
 532 }