bitmap.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2004 Paul Clements, SteelEye Technology, Inc.
   5  *
   6  *    This program is free software; you can redistribute it and/or modify
   7  *    it under the terms of the GNU General Public License as published by
   8  *    the Free Software Foundation; either version 2 of the License, or
   9  *    (at your option) any later version.
  10  *
  11  *    This program is distributed in the hope that it will be useful,
  12  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *    GNU General Public License for more details.
  15  *
  16  *    You should have received a copy of the GNU General Public License
  17  *    along with this program; if not, write to the Free Software
  18  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "mdadm.h"
  22
  23 inline void sb_le_to_cpu(bitmap_super_t *sb)
  24 {
  25         sb->magic = __le32_to_cpu(sb->magic);
  26         sb->version = __le32_to_cpu(sb->version);
  27         /* uuid gets no translation */
  28         sb->events = __le64_to_cpu(sb->events);
  29         sb->events_cleared = __le64_to_cpu(sb->events_cleared);
  30         sb->state = __le32_to_cpu(sb->state);
  31         sb->chunksize = __le32_to_cpu(sb->chunksize);
  32         sb->daemon_sleep = __le32_to_cpu(sb->daemon_sleep);
  33         sb->sync_size = __le64_to_cpu(sb->sync_size);
  34         sb->write_behind = __le32_to_cpu(sb->write_behind);
  35 }
  36
  37 inline void sb_cpu_to_le(bitmap_super_t *sb)
  38 {
  39         sb_le_to_cpu(sb); /* these are really the same thing */
  40 }
  41
  42 mapping_t bitmap_states[] = {
  43         { "OK", 0 },
  44         { "Out of date", 2 },
  45         { NULL, -1 }
  46 };
  47
  48 const char *bitmap_state(int state_num)
  49 {
  50         char *state = map_num(bitmap_states, state_num);
  51         return state ? state : "Unknown";
  52 }
  53
  54 const char *human_chunksize(unsigned long bytes)
  55 {
  56         static char buf[16];
  57         char *suffixes[] = { "B", "KB", "MB", "GB", "TB", NULL };
  58         int i = 0;
  59
  60         while (bytes >> 10) {
  61                 bytes >>= 10;
  62                 i++;
  63         }
  64
  65         snprintf(buf, sizeof(buf), "%lu %s", bytes, suffixes[i]);
  66
  67         return buf;
  68 }
  69
  70 typedef struct bitmap_info_s {
  71         bitmap_super_t sb;
  72         unsigned long long total_bits;
  73         unsigned long long dirty_bits;
  74 } bitmap_info_t;
  75
  76 /* count the dirty bits in the first num_bits of byte */
  77 inline int count_dirty_bits_byte(char byte, int num_bits)
  78 {
  79         int num = 0;
  80
  81         switch (num_bits) { /* fall through... */
  82                 case 8: if (byte & 128) num++;
  83                 case 7: if (byte &  64) num++;
  84                 case 6: if (byte &  32) num++;
  85                 case 5: if (byte &  16) num++;
  86                 case 4: if (byte &   8) num++;
  87                 case 3: if (byte &   4) num++;
  88                 case 2: if (byte &   2) num++;
  89                 case 1: if (byte &   1) num++;
  90                 default: break;
  91         }
  92
  93         return num;
  94 }
  95
  96 int count_dirty_bits(char *buf, int num_bits)
  97 {
  98         int i, num = 0;
  99
 100         for (i=0; i < num_bits / 8; i++)
 101                 num += count_dirty_bits_byte(buf[i], 8);
 102
 103         if (num_bits % 8) /* not an even byte boundary */
 104                 num += count_dirty_bits_byte(buf[i], num_bits % 8);
 105
 106         return num;
 107 }
 108
 109 /* calculate the size of the bitmap given the array size and bitmap chunksize */
 110 unsigned long long bitmap_bits(unsigned long long array_size,
 111                                 unsigned long chunksize)
 112 {
 113         return (array_size * 512 + chunksize - 1) / chunksize;
 114 }
 115
 116 unsigned long bitmap_sectors(struct bitmap_super_s *bsb)
 117 {
 118         unsigned long long bits = bitmap_bits(__le64_to_cpu(bsb->sync_size),
 119                                               __le32_to_cpu(bsb->chunksize));
 120         int bits_per_sector = 8*512;
 121         return (bits + bits_per_sector - 1) / bits_per_sector;
 122 }
 123
 124
 125 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 126 {
 127         /* Note: fd might be open O_DIRECT, so we must be
 128          * careful to align reads properly
 129          */
 130         unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
 131         bitmap_info_t *info;
 132         void *buf;
 133         int n, skip;
 134
 135         if (posix_memalign(&buf, 512, 8192) != 0) {
 136                 fprintf(stderr, Name ": failed to allocate 8192 bytes\n");
 137                 return NULL;
 138         }
 139         n = read(fd, buf, 8192);
 140
 141         info = malloc(sizeof(*info));
 142         if (info == NULL) {
 143 #if __GNUC__ < 3
 144                 fprintf(stderr, Name ": failed to allocate %d bytes\n",
 145                                 (int)sizeof(*info));
 146 #else
 147                 fprintf(stderr, Name ": failed to allocate %zd bytes\n",
 148                                 sizeof(*info));
 149 #endif
 150                 return NULL;
 151         }
 152
 153         if (n < sizeof(info->sb)) {
 154                 fprintf(stderr, Name ": failed to read superblock of bitmap "
 155                         "file: %s\n", strerror(errno));
 156                 free(info);
 157                 return NULL;
 158         }
 159         memcpy(&info->sb, buf, sizeof(info->sb));
 160         skip = sizeof(info->sb);
 161
 162         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 163
 164         if (brief || info->sb.sync_size == 0 || info->sb.chunksize == 0)
 165                 goto out;
 166
 167         /* read the rest of the file counting total bits and dirty bits --
 168          * we stop when either:
 169          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 170          *    are dirty
 171          * 2) we've read the full bitmap, in which case we ignore any trailing
 172          *    data in the file
 173          */
 174         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 175
 176         while(read_bits < total_bits) {
 177                 unsigned long long remaining = total_bits - read_bits;
 178
 179                 if (n == 0) {
 180                         n = read(fd, buf, 8192);
 181                         skip = 0;
 182                         if (n <= 0)
 183                                 break;
 184                 }
 185                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 186                         remaining = (n-skip) * 8;
 187
 188                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 189
 190                 read_bits += remaining;
 191                 n = 0;
 192         }
 193
 194         if (read_bits < total_bits) { /* file truncated... */
 195                 fprintf(stderr, Name ": WARNING: bitmap file is not large "
 196                         "enough for array size %llu!\n\n",
 197                         (unsigned long long)info->sb.sync_size);
 198                 total_bits = read_bits;
 199         }
 200 out:
 201         info->total_bits = total_bits;
 202         info->dirty_bits = dirty_bits;
 203         return info;
 204 }
 205
 206 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 207 {
 208         int fd;
 209         bitmap_info_t *info;
 210         struct stat stb;
 211         struct supertype *st = *stp;
 212
 213         if (stat(filename, &stb) < 0) {
 214                 fprintf(stderr, Name ": failed to find file %s: %s\n",
 215                         filename, strerror(errno));
 216                 return NULL;
 217         }
 218         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 219                 fd = open(filename, O_RDONLY);
 220                 if (fd < 0) {
 221                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 222                                 filename, strerror(errno));
 223                         return NULL;
 224                 }
 225                 /* block device, so we are probably after an internal bitmap */
 226                 if (!st) st = guess_super(fd);
 227                 if (!st) {
 228                         /* just look at device... */
 229                         lseek(fd, 0, 0);
 230                 } else {
 231                         st->ss->locate_bitmap(st, fd);
 232                 }
 233                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 234                 *stp = st;
 235         } else {
 236                 fd = open(filename, O_RDONLY|O_DIRECT);
 237                 if (fd < 0) {
 238                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 239                                 filename, strerror(errno));
 240                         return NULL;
 241                 }
 242         }
 243
 244         info = bitmap_fd_read(fd, brief);
 245         close(fd);
 246         return info;
 247 }
 248
 249 __u32 swapl(__u32 l)
 250 {
 251         char *c = (char*)&l;
 252         char t= c[0];
 253         c[0] = c[3];
 254         c[3] = t;
 255
 256         t = c[1];
 257         c[1] = c[2];
 258         c[2] = t;
 259         return l;
 260 }
 261 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 262 {
 263         /*
 264          * Read the bitmap file and display its contents
 265          */
 266
 267         bitmap_super_t *sb;
 268         bitmap_info_t *info;
 269         int rv = 1;
 270         char buf[64];
 271         int swap;
 272         __u32 uuid32[4];
 273
 274         info = bitmap_file_read(filename, brief, &st);
 275         if (!info)
 276                 return rv;
 277
 278         sb = &info->sb;
 279         printf("        Filename : %s\n", filename);
 280         printf("           Magic : %08x\n", sb->magic);
 281         if (sb->magic != BITMAP_MAGIC) {
 282                 fprintf(stderr, Name ": invalid bitmap magic 0x%x, the bitmap file appears to be corrupted\n", sb->magic);
 283         }
 284         printf("         Version : %d\n", sb->version);
 285         if (sb->version < BITMAP_MAJOR_LO ||
 286             sb->version > BITMAP_MAJOR_HI) {
 287                 fprintf(stderr, Name ": unknown bitmap version %d, either the bitmap file is corrupted or you need to upgrade your tools\n", sb->version);
 288                 goto free_info;
 289         }
 290
 291         rv = 0;
 292         if (st)
 293                 swap = st->ss->swapuuid;
 294         else
 295 #if __BYTE_ORDER == BIG_ENDIAN
 296                 swap = 0;
 297 #else
 298                 swap = 1;
 299 #endif
 300         memcpy(uuid32, sb->uuid, 16);
 301         if (swap)
 302                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 303                        swapl(uuid32[0]),
 304                        swapl(uuid32[1]),
 305                        swapl(uuid32[2]),
 306                        swapl(uuid32[3]));
 307         else
 308                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 309                        uuid32[0],
 310                        uuid32[1],
 311                        uuid32[2],
 312                        uuid32[3]);
 313
 314         printf("          Events : %llu\n", (unsigned long long)sb->events);
 315         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 316         printf("           State : %s\n", bitmap_state(sb->state));
 317         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 318         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 319         if (sb->write_behind)
 320                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 321         else
 322                 sprintf(buf, "Normal");
 323         printf("      Write Mode : %s\n", buf);
 324         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 325                                         human_size(sb->sync_size * 512));
 326         if (brief)
 327                 goto free_info;
 328         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 329                         info->total_bits, info->dirty_bits,
 330                         100.0 * info->dirty_bits / (info->total_bits + 1));
 331 free_info:
 332         free(info);
 333         return rv;
 334 }
 335
 336 int CreateBitmap(char *filename, int force, char uuid[16],
 337                  unsigned long chunksize, unsigned long daemon_sleep,
 338                  unsigned long write_behind,
 339                  unsigned long long array_size /* sectors */,
 340                  int major)
 341 {
 342         /*
 343          * Create a bitmap file with a superblock and (optionally) a full bitmap
 344          */
 345
 346         FILE *fp;
 347         int rv = 1;
 348         char block[512];
 349         bitmap_super_t sb;
 350         long long bytes, filesize;
 351
 352         if (!force && access(filename, F_OK) == 0) {
 353                 fprintf(stderr, Name ": bitmap file %s already exists, use --force to overwrite\n", filename);
 354                 return rv;
 355         }
 356
 357         fp = fopen(filename, "w");
 358         if (fp == NULL) {
 359                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 360                         filename, strerror(errno));
 361                 return rv;
 362         }
 363
 364         if (chunksize == UnSet) {
 365                 /* We don't want more than 2^21 chunks, as 2^11 fill up one
 366                  * 4K page (2 bytes per chunk), and 2^10 address of those
 367                  * fill up a 4K indexing page.  2^20 might be safer, especially
 368                  * on 64bit hosts, so use that.
 369                  */
 370                 chunksize = DEFAULT_BITMAP_CHUNK;
 371                 /* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
 372                 while (array_size > (chunksize << (20-9)))
 373                         chunksize <<= 1;
 374         }
 375
 376         memset(&sb, 0, sizeof(sb));
 377         sb.magic = BITMAP_MAGIC;
 378         sb.version = major;
 379         if (uuid != NULL)
 380                 memcpy(sb.uuid, uuid, 16);
 381         sb.chunksize = chunksize;
 382         sb.daemon_sleep = daemon_sleep;
 383         sb.write_behind = write_behind;
 384         sb.sync_size = array_size;
 385
 386         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 387
 388         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 389                 fprintf(stderr, Name ": failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 390                 goto out;
 391         }
 392
 393         /* calculate the size of the bitmap and write it to disk */
 394         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 395         if (!bytes) {
 396                 rv = 0;
 397                 goto out;
 398         }
 399
 400         filesize = bytes + sizeof(sb);
 401
 402         memset(block, 0xff, sizeof(block));
 403
 404         while (bytes > 0) {
 405                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 406                         fprintf(stderr, Name ": failed to write bitmap file %s: %s\n", filename, strerror(errno));
 407                         goto out;
 408                 }
 409                 bytes -= sizeof(block);
 410         }
 411
 412         rv = 0;
 413         fflush(fp);
 414         /* make the file be the right size (well, to the nearest byte) */
 415         if (ftruncate(fileno(fp), filesize))
 416                 perror("ftrunace");
 417 out:
 418         fclose(fp);
 419         if (rv)
 420                 unlink(filename); /* possibly corrupted, better get rid of it */
 421         return rv;
 422 }
 423
 424 int bitmap_update_uuid(int fd, int *uuid, int swap)
 425 {
 426         struct bitmap_super_s bm;
 427         if (lseek(fd, 0, 0) != 0)
 428                 return 1;
 429         if (read(fd, &bm, sizeof(bm)) != sizeof(bm))
 430                 return 1;
 431         if (bm.magic != __cpu_to_le32(BITMAP_MAGIC))
 432                 return 1;
 433         copy_uuid(bm.uuid, uuid, swap);
 434         if (lseek(fd, 0, 0) != 0)
 435                 return 2;
 436         if (write(fd, &bm, sizeof(bm)) != sizeof(bm)) {
 437                 lseek(fd, 0, 0);
 438                 return 2;
 439         }
 440         lseek(fd, 0, 0);
 441         return 0;
 442 }