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 #define min(a,b) (((a) < (b)) ? (a) : (b))
  24
  25 inline void sb_le_to_cpu(bitmap_super_t *sb)
  26 {
  27         sb->magic = __le32_to_cpu(sb->magic);
  28         sb->version = __le32_to_cpu(sb->version);
  29         /* uuid gets no translation */
  30         sb->events = __le64_to_cpu(sb->events);
  31         sb->events_cleared = __le64_to_cpu(sb->events_cleared);
  32         sb->state = __le32_to_cpu(sb->state);
  33         sb->chunksize = __le32_to_cpu(sb->chunksize);
  34         sb->daemon_sleep = __le32_to_cpu(sb->daemon_sleep);
  35         sb->sync_size = __le64_to_cpu(sb->sync_size);
  36         sb->write_behind = __le32_to_cpu(sb->write_behind);
  37 }
  38
  39 inline void sb_cpu_to_le(bitmap_super_t *sb)
  40 {
  41         sb_le_to_cpu(sb); /* these are really the same thing */
  42 }
  43
  44 mapping_t bitmap_states[] = {
  45         { "OK", 0 },
  46         { "Out of date", 2 },
  47         { NULL, -1 }
  48 };
  49
  50 const char *bitmap_state(int state_num)
  51 {
  52         char *state = map_num(bitmap_states, state_num);
  53         return state ? state : "Unknown";
  54 }
  55
  56 const char *human_chunksize(unsigned long bytes)
  57 {
  58         static char buf[16];
  59         char *suffixes[] = { "B", "KB", "MB", "GB", "TB", NULL };
  60         int i = 0;
  61
  62         while (bytes >> 10) {
  63                 bytes >>= 10;
  64                 i++;
  65         }
  66
  67         snprintf(buf, sizeof(buf), "%lu %s", bytes, suffixes[i]);
  68
  69         return buf;
  70 }
  71
  72 typedef struct bitmap_info_s {
  73         bitmap_super_t sb;
  74         unsigned long long total_bits;
  75         unsigned long long dirty_bits;
  76 } bitmap_info_t;
  77
  78 /* count the dirty bits in the first num_bits of byte */
  79 inline int count_dirty_bits_byte(char byte, int num_bits)
  80 {
  81         int num = 0;
  82
  83         switch (num_bits) { /* fall through... */
  84                 case 8: if (byte & 128) num++;
  85                 case 7: if (byte &  64) num++;
  86                 case 6: if (byte &  32) num++;
  87                 case 5: if (byte &  16) num++;
  88                 case 4: if (byte &   8) num++;
  89                 case 3: if (byte &   4) num++;
  90                 case 2: if (byte &   2) num++;
  91                 case 1: if (byte &   1) num++;
  92                 default: break;
  93         }
  94
  95         return num;
  96 }
  97
  98 int count_dirty_bits(char *buf, int num_bits)
  99 {
 100         int i, num = 0;
 101
 102         for (i=0; i < num_bits / 8; i++)
 103                 num += count_dirty_bits_byte(buf[i], 8);
 104
 105         if (num_bits % 8) /* not an even byte boundary */
 106                 num += count_dirty_bits_byte(buf[i], num_bits % 8);
 107
 108         return num;
 109 }
 110
 111 /* calculate the size of the bitmap given the array size and bitmap chunksize */
 112 unsigned long long bitmap_bits(unsigned long long array_size,
 113                                 unsigned long chunksize)
 114 {
 115         return (array_size * 512 + chunksize - 1) / chunksize;
 116 }
 117
 118 unsigned long bitmap_sectors(struct bitmap_super_s *bsb)
 119 {
 120         unsigned long long bits = bitmap_bits(__le64_to_cpu(bsb->sync_size),
 121                                               __le32_to_cpu(bsb->chunksize));
 122         int bits_per_sector = 8*512;
 123         return (bits + bits_per_sector - 1) / bits_per_sector;
 124 }
 125
 126
 127 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 128 {
 129         /* Note: fd might be open O_DIRECT, so we must be
 130          * careful to align reads properly
 131          */
 132         unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
 133         bitmap_info_t *info;
 134         char *buf, *unaligned;
 135         int n, skip;
 136
 137         unaligned = malloc(8192*2);
 138         buf = (char*) ((unsigned long)unaligned | 8191)+1;
 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                 free(unaligned);
 158                 return NULL;
 159         }
 160         memcpy(&info->sb, buf, sizeof(info->sb));
 161         skip = sizeof(info->sb);
 162
 163         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 164
 165         if (brief || info->sb.sync_size == 0 || info->sb.chunksize == 0)
 166                 goto out;
 167
 168         /* read the rest of the file counting total bits and dirty bits --
 169          * we stop when either:
 170          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 171          *    are dirty
 172          * 2) we've read the full bitmap, in which case we ignore any trailing
 173          *    data in the file
 174          */
 175         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 176
 177         while(read_bits < total_bits) {
 178                 unsigned long long remaining = total_bits - read_bits;
 179
 180                 if (n == 0) {
 181                         n = read(fd, buf, 8192);
 182                         skip = 0;
 183                         if (n <= 0)
 184                                 break;
 185                 }
 186                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 187                         remaining = (n-skip) * 8;
 188
 189                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 190
 191                 read_bits += remaining;
 192                 n = 0;
 193         }
 194
 195         if (read_bits < total_bits) { /* file truncated... */
 196                 fprintf(stderr, Name ": WARNING: bitmap file is not large "
 197                         "enough for array size %llu!\n\n",
 198                         (unsigned long long)info->sb.sync_size);
 199                 total_bits = read_bits;
 200         }
 201 out:
 202         info->total_bits = total_bits;
 203         info->dirty_bits = dirty_bits;
 204         return info;
 205 }
 206
 207 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 208 {
 209         int fd;
 210         bitmap_info_t *info;
 211         struct stat stb;
 212         struct supertype *st = *stp;
 213
 214         if (stat(filename, &stb) < 0) {
 215                 fprintf(stderr, Name ": failed to find file %s: %s\n",
 216                         filename, strerror(errno));
 217                 return NULL;
 218         }
 219         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 220                 fd = open(filename, O_RDONLY);
 221                 if (fd < 0) {
 222                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 223                                 filename, strerror(errno));
 224                         return NULL;
 225                 }
 226                 /* block device, so we are probably after an internal bitmap */
 227                 if (!st) st = guess_super(fd);
 228                 if (!st) {
 229                         /* just look at device... */
 230                         lseek(fd, 0, 0);
 231                 } else {
 232                         st->ss->locate_bitmap(st, fd);
 233                 }
 234                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 235                 *stp = st;
 236         } else {
 237                 fd = open(filename, O_RDONLY|O_DIRECT);
 238                 if (fd < 0) {
 239                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 240                                 filename, strerror(errno));
 241                         return NULL;
 242                 }
 243         }
 244
 245         info = bitmap_fd_read(fd, brief);
 246         close(fd);
 247         return info;
 248 }
 249
 250 __u32 swapl(__u32 l)
 251 {
 252         char *c = (char*)&l;
 253         char t= c[0];
 254         c[0] = c[3];
 255         c[3] = t;
 256
 257         t = c[1];
 258         c[1] = c[2];
 259         c[2] = t;
 260         return l;
 261 }
 262 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 263 {
 264         /*
 265          * Read the bitmap file and display its contents
 266          */
 267
 268         bitmap_super_t *sb;
 269         bitmap_info_t *info;
 270         int rv = 1;
 271         char buf[64];
 272         int swap;
 273         __u32 uuid32[4];
 274
 275         info = bitmap_file_read(filename, brief, &st);
 276         if (!info)
 277                 return rv;
 278
 279         sb = &info->sb;
 280         printf("        Filename : %s\n", filename);
 281         printf("           Magic : %08x\n", sb->magic);
 282         if (sb->magic != BITMAP_MAGIC) {
 283                 fprintf(stderr, Name ": invalid bitmap magic 0x%x, the bitmap file appears to be corrupted\n", sb->magic);
 284         }
 285         printf("         Version : %d\n", sb->version);
 286         if (sb->version < BITMAP_MAJOR_LO ||
 287             sb->version > BITMAP_MAJOR_HI) {
 288                 fprintf(stderr, Name ": unknown bitmap version %d, either the bitmap file is corrupted or you need to upgrade your tools\n", sb->version);
 289                 goto free_info;
 290         }
 291
 292         rv = 0;
 293         if (st)
 294                 swap = st->ss->swapuuid;
 295         else
 296 #if __BYTE_ORDER == BIG_ENDIAN
 297                 swap = 0;
 298 #else
 299                 swap = 1;
 300 #endif
 301         memcpy(uuid32, sb->uuid, 16);
 302         if (swap)
 303                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 304                        swapl(uuid32[0]),
 305                        swapl(uuid32[1]),
 306                        swapl(uuid32[2]),
 307                        swapl(uuid32[3]));
 308         else
 309                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 310                        uuid32[0],
 311                        uuid32[1],
 312                        uuid32[2],
 313                        uuid32[3]);
 314
 315         printf("          Events : %llu\n", (unsigned long long)sb->events);
 316         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 317         printf("           State : %s\n", bitmap_state(sb->state));
 318         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 319         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 320         if (sb->write_behind)
 321                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 322         else
 323                 sprintf(buf, "Normal");
 324         printf("      Write Mode : %s\n", buf);
 325         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 326                                         human_size(sb->sync_size * 512));
 327         if (brief)
 328                 goto free_info;
 329         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 330                         info->total_bits, info->dirty_bits,
 331                         100.0 * info->dirty_bits / (info->total_bits + 1));
 332 free_info:
 333         free(info);
 334         return rv;
 335 }
 336
 337 int CreateBitmap(char *filename, int force, char uuid[16],
 338                  unsigned long chunksize, unsigned long daemon_sleep,
 339                  unsigned long write_behind,
 340                  unsigned long long array_size /* sectors */,
 341                  int major)
 342 {
 343         /*
 344          * Create a bitmap file with a superblock and (optionally) a full bitmap
 345          */
 346
 347         FILE *fp;
 348         int rv = 1;
 349         char block[512];
 350         bitmap_super_t sb;
 351         long long bytes, filesize;
 352
 353         if (!force && access(filename, F_OK) == 0) {
 354                 fprintf(stderr, Name ": bitmap file %s already exists, use --force to overwrite\n", filename);
 355                 return rv;
 356         }
 357
 358         fp = fopen(filename, "w");
 359         if (fp == NULL) {
 360                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 361                         filename, strerror(errno));
 362                 return rv;
 363         }
 364
 365         if (chunksize == UnSet) {
 366                 /* We don't want more than 2^21 chunks, as 2^11 fill up one
 367                  * 4K page (2 bytes per chunk), and 2^10 address of those
 368                  * fill up a 4K indexing page.  2^20 might be safer, especially
 369                  * on 64bit hosts, so use that.
 370                  */
 371                 chunksize = DEFAULT_BITMAP_CHUNK;
 372                 /* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
 373                 while (array_size > (chunksize << (20-9)))
 374                         chunksize <<= 1;
 375         }
 376
 377         memset(&sb, 0, sizeof(sb));
 378         sb.magic = BITMAP_MAGIC;
 379         sb.version = major;
 380         if (uuid != NULL)
 381                 memcpy(sb.uuid, uuid, 16);
 382         sb.chunksize = chunksize;
 383         sb.daemon_sleep = daemon_sleep;
 384         sb.write_behind = write_behind;
 385         sb.sync_size = array_size;
 386
 387         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 388
 389         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 390                 fprintf(stderr, Name ": failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 391                 goto out;
 392         }
 393
 394         /* calculate the size of the bitmap and write it to disk */
 395         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 396         if (!bytes) {
 397                 rv = 0;
 398                 goto out;
 399         }
 400
 401         filesize = bytes + sizeof(sb);
 402
 403         memset(block, 0xff, sizeof(block));
 404
 405         while (bytes > 0) {
 406                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 407                         fprintf(stderr, Name ": failed to write bitmap file %s: %s\n", filename, strerror(errno));
 408                         goto out;
 409                 }
 410                 bytes -= sizeof(block);
 411         }
 412
 413         rv = 0;
 414         fflush(fp);
 415         /* make the file be the right size (well, to the nearest byte) */
 416         if (ftruncate(fileno(fp), filesize))
 417                 perror("ftrunace");
 418 out:
 419         fclose(fp);
 420         if (rv)
 421                 unlink(filename); /* possibly corrupted, better get rid of it */
 422         return rv;
 423 }
 424
 425 int bitmap_update_uuid(int fd, int *uuid, int swap)
 426 {
 427         struct bitmap_super_s bm;
 428         if (lseek(fd, 0, 0) != 0)
 429                 return 1;
 430         if (read(fd, &bm, sizeof(bm)) != sizeof(bm))
 431                 return 1;
 432         if (bm.magic != __cpu_to_le32(BITMAP_MAGIC))
 433                 return 1;
 434         copy_uuid(bm.uuid, uuid, swap);
 435         if (lseek(fd, 0, 0) != 0)
 436                 return 2;
 437         if (write(fd, &bm, sizeof(bm)) != sizeof(bm)) {
 438                 lseek(fd, 0, 0);
 439                 return 2;
 440         }
 441         lseek(fd, 0, 0);
 442         return 0;
 443 }