Monitor.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2006 Neil Brown <neilb@suse.de>
   5  *
   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *    Author: Neil Brown
  22  *    Email: <neilb@cse.unsw.edu.au>
  23  *    Paper: Neil Brown
  24  *           School of Computer Science and Engineering
  25  *           The University of New South Wales
  26  *           Sydney, 2052
  27  *           Australia
  28  */
  29
  30 #include        "mdadm.h"
  31 #include        "md_p.h"
  32 #include        "md_u.h"
  33 #include        <sys/wait.h>
  34 #include        <signal.h>
  35 #include        <limits.h>
  36 #include        <syslog.h>
  37
  38 static void alert(char *event, char *dev, char *disc, char *mailaddr, char *mailfrom,
  39                   char *cmd, int dosyslog);
  40
  41 static char *percentalerts[] = {
  42         "RebuildStarted",
  43         "Rebuild20",
  44         "Rebuild40",
  45         "Rebuild60",
  46         "Rebuild80",
  47 };
  48
  49 /* The largest number of disks current arrays can manage is 384
  50  * This really should be dynamically, but that will have to wait
  51  * At least it isn't MD_SB_DISKS.
  52  */
  53 #define MaxDisks 384
  54 int Monitor(mddev_dev_t devlist,
  55             char *mailaddr, char *alert_cmd,
  56             int period, int daemonise, int scan, int oneshot,
  57             int dosyslog, int test, char* pidfile)
  58 {
  59         /*
  60          * Every few seconds, scan every md device looking for changes
  61          * When a change is found, log it, possibly run the alert command,
  62          * and possibly send Email
  63          *
  64          * For each array, we record:
  65          *   Update time
  66          *   active/working/failed/spare drives
  67          *   State of each device.
  68          *   %rebuilt if rebuilding
  69          *
  70          * If the update time changes, check out all the data again
  71          * It is possible that we cannot get the state of each device
  72          * due to bugs in the md kernel module.
  73          * We also read /proc/mdstat to get rebuild percent,
  74          * and to get state on all active devices incase of kernel bug.
  75          *
  76          * Events are:
  77          *    Fail
  78          *      An active device had Faulty set or Active/Sync removed
  79          *    FailSpare
  80          *      A spare device had Faulty set
  81          *    SpareActive
  82          *      An active device had a reverse transition
  83          *    RebuildStarted
  84          *      percent went from -1 to +ve
  85          *    Rebuild20 Rebuild40 Rebuild60 Rebuild80
  86          *      percent went from below to not-below that number
  87          *    DeviceDisappeared
  88          *      Couldn't access a device which was previously visible
  89          *
  90          * if we detect an array with active<raid and spare==0
  91          * we look at other arrays that have same spare-group
  92          * If we find one with active==raid and spare>0,
  93          *  and if we can get_disk_info and find a name
  94          *  Then we hot-remove and hot-add to the other array
  95          *
  96          * If devlist is NULL, then we can monitor everything because --scan
  97          * was given.  We get an initial list from config file and add anything
  98          * that appears in /proc/mdstat
  99          */
 100
 101         struct state {
 102                 char *devname;
 103                 int devnum;     /* to sync with mdstat info */
 104                 long utime;
 105                 int err;
 106                 char *spare_group;
 107                 int active, working, failed, spare, raid;
 108                 int expected_spares;
 109                 int devstate[MaxDisks];
 110                 int devid[MaxDisks];
 111                 int percent;
 112                 struct state *next;
 113         } *statelist = NULL;
 114         int finished = 0;
 115         struct mdstat_ent *mdstat = NULL;
 116         char *mailfrom = NULL;
 117
 118         if (!mailaddr) {
 119                 mailaddr = conf_get_mailaddr();
 120                 if (mailaddr && ! scan)
 121                         fprintf(stderr, Name ": Monitor using email address \"%s\" from config file\n",
 122                                mailaddr);
 123         }
 124         mailfrom = conf_get_mailfrom();
 125
 126         if (!alert_cmd) {
 127                 alert_cmd = conf_get_program();
 128                 if (alert_cmd && ! scan)
 129                         fprintf(stderr, Name ": Monitor using program \"%s\" from config file\n",
 130                                alert_cmd);
 131         }
 132         if (scan && !mailaddr && !alert_cmd) {
 133                 fprintf(stderr, Name ": No mail address or alert command - not monitoring.\n");
 134                 return 1;
 135         }
 136
 137         if (daemonise) {
 138                 int pid = fork();
 139                 if (pid > 0) {
 140                         if (!pidfile)
 141                                 printf("%d\n", pid);
 142                         else {
 143                                 FILE *pid_file;
 144                                 pid_file=fopen(pidfile, "w");
 145                                 if (!pid_file)
 146                                         perror("cannot create pid file");
 147                                 else {
 148                                         fprintf(pid_file,"%d\n", pid);
 149                                         fclose(pid_file);
 150                                 }
 151                         }
 152                         return 0;
 153                 }
 154                 if (pid < 0) {
 155                         perror("daemonise");
 156                         return 1;
 157                 }
 158                 close(0);
 159                 open("/dev/null", 3);
 160                 dup2(0,1);
 161                 dup2(0,2);
 162                 setsid();
 163         }
 164
 165         if (devlist == NULL) {
 166                 mddev_ident_t mdlist = conf_get_ident(NULL);
 167                 for (; mdlist; mdlist=mdlist->next) {
 168                         struct state *st = malloc(sizeof *st);
 169                         if (st == NULL)
 170                                 continue;
 171                         st->devname = strdup(mdlist->devname);
 172                         st->utime = 0;
 173                         st->next = statelist;
 174                         st->err = 0;
 175                         st->devnum = INT_MAX;
 176                         st->percent = -2;
 177                         st->expected_spares = mdlist->spare_disks;
 178                         if (mdlist->spare_group)
 179                                 st->spare_group = strdup(mdlist->spare_group);
 180                         else
 181                                 st->spare_group = NULL;
 182                         statelist = st;
 183                 }
 184         } else {
 185                 mddev_dev_t dv;
 186                 for (dv=devlist ; dv; dv=dv->next) {
 187                         mddev_ident_t mdlist = conf_get_ident(dv->devname);
 188                         struct state *st = malloc(sizeof *st);
 189                         if (st == NULL)
 190                                 continue;
 191                         st->devname = strdup(dv->devname);
 192                         st->utime = 0;
 193                         st->next = statelist;
 194                         st->err = 0;
 195                         st->devnum = INT_MAX;
 196                         st->percent = -2;
 197                         st->expected_spares = -1;
 198                         st->spare_group = NULL;
 199                         if (mdlist) {
 200                                 st->expected_spares = mdlist->spare_disks;
 201                                 if (mdlist->spare_group)
 202                                         st->spare_group = strdup(mdlist->spare_group);
 203                         }
 204                         statelist = st;
 205                 }
 206         }
 207
 208
 209         while (! finished) {
 210                 int new_found = 0;
 211                 struct state *st;
 212
 213                 if (mdstat)
 214                         free_mdstat(mdstat);
 215                 mdstat = mdstat_read(oneshot?0:1, 0);
 216
 217                 for (st=statelist; st; st=st->next) {
 218                         struct { int state, major, minor; } info[MaxDisks];
 219                         mdu_array_info_t array;
 220                         struct mdstat_ent *mse = NULL, *mse2;
 221                         char *dev = st->devname;
 222                         int fd;
 223                         unsigned int i;
 224
 225                         if (test)
 226                                 alert("TestMessage", dev, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 227                         fd = open(dev, O_RDONLY);
 228                         if (fd < 0) {
 229                                 if (!st->err)
 230                                         alert("DeviceDisappeared", dev, NULL,
 231                                               mailaddr, mailfrom, alert_cmd, dosyslog);
 232 /*                                      fprintf(stderr, Name ": cannot open %s: %s\n",
 233                                                 dev, strerror(errno));
 234 */                              st->err=1;
 235                                 continue;
 236                         }
 237                         fcntl(fd, F_SETFD, FD_CLOEXEC);
 238                         if (ioctl(fd, GET_ARRAY_INFO, &array)<0) {
 239                                 if (!st->err)
 240                                         alert("DeviceDisappeared", dev, NULL,
 241                                               mailaddr, mailfrom, alert_cmd, dosyslog);
 242 /*                                      fprintf(stderr, Name ": cannot get array info for %s: %s\n",
 243                                                 dev, strerror(errno));
 244 */                              st->err=1;
 245                                 close(fd);
 246                                 continue;
 247                         }
 248                         /* It's much easier to list what array levels can't
 249                          * have a device disappear than all of them that can
 250                          */
 251                         if (array.level == 0 || array.level == -1) {
 252                                 if (!st->err)
 253                                         alert("DeviceDisappeared", dev, "Wrong-Level",
 254                                               mailaddr, mailfrom, alert_cmd, dosyslog);
 255                                 st->err = 1;
 256                                 close(fd);
 257                                 continue;
 258                         }
 259                         if (st->devnum == INT_MAX) {
 260                                 struct stat stb;
 261                                 if (fstat(fd, &stb) == 0 &&
 262                                     (S_IFMT&stb.st_mode)==S_IFBLK) {
 263                                         if (major(stb.st_rdev) == MD_MAJOR)
 264                                                 st->devnum = minor(stb.st_rdev);
 265                                         else
 266                                                 st->devnum = -1- (minor(stb.st_rdev)>>6);
 267                                 }
 268                         }
 269
 270                         for (mse2 = mdstat ; mse2 ; mse2=mse2->next)
 271                                 if (mse2->devnum == st->devnum) {
 272                                         mse2->devnum = INT_MAX; /* flag it as "used" */
 273                                         mse = mse2;
 274                                 }
 275
 276                         if (st->utime == array.utime &&
 277                             st->failed == array.failed_disks &&
 278                             st->working == array.working_disks &&
 279                             st->spare == array.spare_disks &&
 280                             (mse == NULL  || (
 281                                     mse->percent == st->percent
 282                                     ))) {
 283                                 close(fd);
 284                                 st->err = 0;
 285                                 continue;
 286                         }
 287                         if (st->utime == 0 && /* new array */
 288                             mse &&      /* is in /proc/mdstat */
 289                             mse->pattern && strchr(mse->pattern, '_') /* degraded */
 290                                 )
 291                                 alert("DegradedArray", dev, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 292
 293                         if (st->utime == 0 && /* new array */
 294                             st->expected_spares > 0 &&
 295                             array.spare_disks < st->expected_spares)
 296                                 alert("SparesMissing", dev, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 297                         if (mse &&
 298                             st->percent == -1 &&
 299                             mse->percent >= 0)
 300                                 alert("RebuildStarted", dev, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 301                         if (mse &&
 302                             st->percent >= 0 &&
 303                             mse->percent >= 0 &&
 304                             (mse->percent / 20) > (st->percent / 20))
 305                                 alert(percentalerts[mse->percent/20],
 306                                       dev, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 307
 308                         if (mse &&
 309                             mse->percent == -1 &&
 310                             st->percent >= 0) {
 311                                 /* Rebuild/sync/whatever just finished.
 312                                  * If there is a number in /mismatch_cnt,
 313                                  * we should report that.
 314                                  */
 315                                 struct mdinfo *sra =
 316                                        sysfs_read(-1, st->devnum, GET_MISMATCH);
 317                                 if (sra && sra->mismatch_cnt > 0) {
 318                                         char cnt[40];
 319                                         sprintf(cnt, " mismatches found: %d", sra->mismatch_cnt);
 320                                         alert("RebuildFinished", dev, cnt, mailaddr, mailfrom, alert_cmd, dosyslog);
 321                                 } else
 322                                         alert("RebuildFinished", dev, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 323                                 if (sra)
 324                                         free(sra);
 325                         }
 326
 327                         if (mse)
 328                                 st->percent = mse->percent;
 329
 330
 331                         for (i=0; i<MaxDisks && i <= array.raid_disks + array.nr_disks;
 332                              i++) {
 333                                 mdu_disk_info_t disc;
 334                                 disc.number = i;
 335                                 if (ioctl(fd, GET_DISK_INFO, &disc) >= 0) {
 336                                         info[i].state = disc.state;
 337                                         info[i].major = disc.major;
 338                                         info[i].minor = disc.minor;
 339                                 } else
 340                                         info[i].major = info[i].minor = 0;
 341                         }
 342                         close(fd);
 343
 344                         for (i=0; i<MaxDisks; i++) {
 345                                 mdu_disk_info_t disc = {0};
 346                                 int newstate=0;
 347                                 int change;
 348                                 char *dv = NULL;
 349                                 disc.number = i;
 350                                 if (i > array.raid_disks + array.nr_disks) {
 351                                         newstate = 0;
 352                                         disc.major = disc.minor = 0;
 353                                 } else if (info[i].major || info[i].minor) {
 354                                         newstate = info[i].state;
 355                                         dv = map_dev(info[i].major, info[i].minor, 1);
 356                                         disc.state = newstate;
 357                                         disc.major = info[i].major;
 358                                         disc.minor = info[i].minor;
 359                                 } else if (mse &&  mse->pattern && i < strlen(mse->pattern)) {
 360                                         switch(mse->pattern[i]) {
 361                                         case 'U': newstate = 6 /* ACTIVE/SYNC */; break;
 362                                         case '_': newstate = 0; break;
 363                                         }
 364                                         disc.major = disc.minor = 0;
 365                                 }
 366                                 if (dv == NULL && st->devid[i])
 367                                         dv = map_dev(major(st->devid[i]),
 368                                                      minor(st->devid[i]), 1);
 369                                 change = newstate ^ st->devstate[i];
 370                                 if (st->utime && change && !st->err) {
 371                                         if (i < (unsigned)array.raid_disks &&
 372                                             (((newstate&change)&(1<<MD_DISK_FAULTY)) ||
 373                                              ((st->devstate[i]&change)&(1<<MD_DISK_ACTIVE)) ||
 374                                              ((st->devstate[i]&change)&(1<<MD_DISK_SYNC)))
 375                                                 )
 376                                                 alert("Fail", dev, dv, mailaddr, mailfrom, alert_cmd, dosyslog);
 377                                         else if (i >= (unsigned)array.raid_disks &&
 378                                                  (disc.major || disc.minor) &&
 379                                                  st->devid[i] == makedev(disc.major, disc.minor) &&
 380                                                  ((newstate&change)&(1<<MD_DISK_FAULTY))
 381                                                 )
 382                                                 alert("FailSpare", dev, dv, mailaddr, mailfrom, alert_cmd, dosyslog);
 383                                         else if (i < (unsigned)array.raid_disks &&
 384                                                  (((st->devstate[i]&change)&(1<<MD_DISK_FAULTY)) ||
 385                                                   ((newstate&change)&(1<<MD_DISK_ACTIVE)) ||
 386                                                   ((newstate&change)&(1<<MD_DISK_SYNC)))
 387                                                 )
 388                                                 alert("SpareActive", dev, dv, mailaddr, mailfrom, alert_cmd, dosyslog);
 389                                 }
 390                                 st->devstate[i] = newstate;
 391                                 st->devid[i] = makedev(disc.major, disc.minor);
 392                         }
 393                         st->active = array.active_disks;
 394                         st->working = array.working_disks;
 395                         st->spare = array.spare_disks;
 396                         st->failed = array.failed_disks;
 397                         st->utime = array.utime;
 398                         st->raid = array.raid_disks;
 399                         st->err = 0;
 400                 }
 401                 /* now check if there are any new devices found in mdstat */
 402                 if (scan) {
 403                         struct mdstat_ent *mse;
 404                         for (mse=mdstat; mse; mse=mse->next)
 405                                 if (mse->devnum != INT_MAX &&
 406                                     mse->level &&
 407                                     (strcmp(mse->level, "raid0")!=0 &&
 408                                      strcmp(mse->level, "linear")!=0)
 409                                         ) {
 410                                         struct state *st = malloc(sizeof *st);
 411                                         mdu_array_info_t array;
 412                                         int fd;
 413                                         if (st == NULL)
 414                                                 continue;
 415                                         st->devname = strdup(get_md_name(mse->devnum));
 416                                         if ((fd = open(st->devname, O_RDONLY)) < 0 ||
 417                                             ioctl(fd, GET_ARRAY_INFO, &array)< 0) {
 418                                                 /* no such array */
 419                                                 if (fd >=0) close(fd);
 420                                                 put_md_name(st->devname);
 421                                                 free(st->devname);
 422                                                 free(st);
 423                                                 continue;
 424                                         }
 425                                         close(fd);
 426                                         st->utime = 0;
 427                                         st->next = statelist;
 428                                         st->err = 1;
 429                                         st->devnum = mse->devnum;
 430                                         st->percent = -2;
 431                                         st->spare_group = NULL;
 432                                         st->expected_spares = -1;
 433                                         statelist = st;
 434                                         alert("NewArray", st->devname, NULL, mailaddr, mailfrom, alert_cmd, dosyslog);
 435                                         new_found = 1;
 436                                 }
 437                 }
 438                 /* If an array has active < raid && spare == 0 && spare_group != NULL
 439                  * Look for another array with spare > 0 and active == raid and same spare_group
 440                  *  if found, choose a device and hotremove/hotadd
 441                  */
 442                 for (st = statelist; st; st=st->next)
 443                         if (st->active < st->raid &&
 444                             st->spare == 0 &&
 445                             st->spare_group != NULL) {
 446                                 struct state *st2;
 447                                 for (st2=statelist ; st2 ; st2=st2->next)
 448                                         if (st2 != st &&
 449                                             st2->spare > 0 &&
 450                                             st2->active == st2->raid &&
 451                                             st2->spare_group != NULL &&
 452                                             strcmp(st->spare_group, st2->spare_group) == 0) {
 453                                                 /* try to remove and add */
 454                                                 int fd1 = open(st->devname, O_RDONLY);
 455                                                 int fd2 = open(st2->devname, O_RDONLY);
 456                                                 int dev = -1;
 457                                                 int d;
 458                                                 if (fd1 < 0 || fd2 < 0) {
 459                                                         if (fd1>=0) close(fd1);
 460                                                         if (fd2>=0) close(fd2);
 461                                                         continue;
 462                                                 }
 463                                                 for (d=st2->raid; d < MaxDisks; d++) {
 464                                                         if (st2->devid[d] > 0 &&
 465                                                             st2->devstate[d] == 0) {
 466                                                                 dev = st2->devid[d];
 467                                                                 break;
 468                                                         }
 469                                                 }
 470                                                 if (dev > 0) {
 471                                                         if (ioctl(fd2, HOT_REMOVE_DISK,
 472                                                                   (unsigned long)dev) == 0) {
 473                                                                 if (ioctl(fd1, HOT_ADD_DISK,
 474                                                                           (unsigned long)dev) == 0) {
 475                                                                         alert("MoveSpare", st->devname, st2->devname, mailaddr, mailfrom, alert_cmd, dosyslog);
 476                                                                         close(fd1);
 477                                                                         close(fd2);
 478                                                                         break;
 479                                                                 }
 480                                                                 else ioctl(fd2, HOT_ADD_DISK, (unsigned long) dev);
 481                                                         }
 482                                                 }
 483                                                 close(fd1);
 484                                                 close(fd2);
 485                                         }
 486                         }
 487                 if (!new_found) {
 488                         if (oneshot)
 489                                 break;
 490                         else
 491                                 mdstat_wait(period);
 492                 }
 493                 test = 0;
 494         }
 495         if (pidfile)
 496                 unlink(pidfile);
 497         return 0;
 498 }
 499
 500
 501 static void alert(char *event, char *dev, char *disc, char *mailaddr, char *mailfrom, char *cmd,
 502                   int dosyslog)
 503 {
 504         int priority;
 505
 506         if (!cmd && !mailaddr) {
 507                 time_t now = time(0);
 508
 509                 printf("%1.15s: %s on %s %s\n", ctime(&now)+4, event, dev, disc?disc:"unknown device");
 510         }
 511         if (cmd) {
 512                 int pid = fork();
 513                 switch(pid) {
 514                 default:
 515                         waitpid(pid, NULL, 0);
 516                         break;
 517                 case -1:
 518                         break;
 519                 case 0:
 520                         execl(cmd, cmd, event, dev, disc, NULL);
 521                         exit(2);
 522                 }
 523         }
 524         if (mailaddr &&
 525             (strncmp(event, "Fail", 4)==0 ||
 526              strncmp(event, "Test", 4)==0 ||
 527              strncmp(event, "Spares", 6)==0 ||
 528              strncmp(event, "Degrade", 7)==0)) {
 529                 FILE *mp = popen(Sendmail, "w");
 530                 if (mp) {
 531                         FILE *mdstat;
 532                         char hname[256];
 533                         gethostname(hname, sizeof(hname));
 534                         signal(SIGPIPE, SIG_IGN);
 535                         if (mailfrom)
 536                                 fprintf(mp, "From: %s\n", mailfrom);
 537                         else
 538                                 fprintf(mp, "From: " Name " monitoring <root>\n");
 539                         fprintf(mp, "To: %s\n", mailaddr);
 540                         fprintf(mp, "Subject: %s event on %s:%s\n\n", event, dev, hname);
 541
 542                         fprintf(mp, "This is an automatically generated mail message from " Name "\n");
 543                         fprintf(mp, "running on %s\n\n", hname);
 544
 545                         fprintf(mp, "A %s event had been detected on md device %s.\n\n", event, dev);
 546
 547                         if (disc && disc[0] != ' ')
 548                                 fprintf(mp, "It could be related to component device %s.\n\n", disc);
 549                         if (disc && disc[0] == ' ')
 550                                 fprintf(mp, "Extra information:%s.\n\n", disc);
 551
 552                         fprintf(mp, "Faithfully yours, etc.\n");
 553
 554                         mdstat = fopen("/proc/mdstat", "r");
 555                         if (mdstat) {
 556                                 char buf[8192];
 557                                 int n;
 558                                 fprintf(mp, "\nP.S. The /proc/mdstat file currently contains the following:\n\n");
 559                                 while ( (n=fread(buf, 1, sizeof(buf), mdstat)) > 0)
 560                                         n=fwrite(buf, 1, n, mp); /* yes, i don't care about the result */
 561                                 fclose(mdstat);
 562                         }
 563                         fclose(mp);
 564                 }
 565
 566         }
 567
 568         /* log the event to syslog maybe */
 569         if (dosyslog) {
 570                 /* Log at a different severity depending on the event.
 571                  *
 572                  * These are the critical events:  */
 573                 if (strncmp(event, "Fail", 4)==0 ||
 574                     strncmp(event, "Degrade", 7)==0 ||
 575                     strncmp(event, "DeviceDisappeared", 17)==0)
 576                         priority = LOG_CRIT;
 577                 /* Good to know about, but are not failures: */
 578                 else if (strncmp(event, "Rebuild", 7)==0 ||
 579                          strncmp(event, "MoveSpare", 9)==0 ||
 580                          strncmp(event, "Spares", 6) != 0)
 581                         priority = LOG_WARNING;
 582                 /* Everything else: */
 583                 else
 584                         priority = LOG_INFO;
 585
 586                 if (disc)
 587                         syslog(priority, "%s event detected on md device %s, component device %s", event, dev, disc);
 588                 else
 589                         syslog(priority, "%s event detected on md device %s", event, dev);
 590         }
 591 }
 592
 593 /* Not really Monitor but ... */
 594 int Wait(char *dev)
 595 {
 596         struct stat stb;
 597         int devnum;
 598         int rv = 1;
 599
 600         if (stat(dev, &stb) != 0) {
 601                 fprintf(stderr, Name ": Cannot find %s: %s\n", dev,
 602                         strerror(errno));
 603                 return 2;
 604         }
 605         if (major(stb.st_rdev) == MD_MAJOR)
 606                 devnum = minor(stb.st_rdev);
 607         else
 608                 devnum = -1-(minor(stb.st_rdev)/64);
 609
 610         while(1) {
 611                 struct mdstat_ent *ms = mdstat_read(1, 0);
 612                 struct mdstat_ent *e;
 613
 614                 for (e=ms ; e; e=e->next)
 615                         if (e->devnum == devnum)
 616                                 break;
 617
 618                 if (!e || e->percent < 0) {
 619                         free_mdstat(ms);
 620                         return rv;
 621                 }
 622                 free(ms);
 623                 rv = 0;
 624                 mdstat_wait(5);
 625         }
 626 }