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  46         { "Out of date", 2 },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         void *buf;
 135         int n, skip;
 136
 137         if (posix_memalign(&buf, 512, 8192) != 0) {
 138                 fprintf(stderr, Name ": failed to allocate 8192 bytes\n");
 139                 return NULL;
 140         }
 141         n = read(fd, buf, 8192);
 142
 143         info = malloc(sizeof(*info));
 144         if (info == NULL) {
 145 #if __GNUC__ < 3
 146                 fprintf(stderr, Name ": failed to allocate %d bytes\n",
 147                                 (int)sizeof(*info));
 148 #else
 149                 fprintf(stderr, Name ": failed to allocate %zd bytes\n",
 150                                 sizeof(*info));
 151 #endif
 152                 return NULL;
 153         }
 154
 155         if (n < sizeof(info->sb)) {
 156                 fprintf(stderr, Name ": failed to read superblock of bitmap "
 157                         "file: %s\n", strerror(errno));
 158                 free(info);
 159                 return NULL;
 160         }
 161         memcpy(&info->sb, buf, sizeof(info->sb));
 162         skip = sizeof(info->sb);
 163
 164         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 165
 166         if (brief || info->sb.sync_size == 0 || info->sb.chunksize == 0)
 167                 goto out;
 168
 169         /* read the rest of the file counting total bits and dirty bits --
 170          * we stop when either:
 171          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 172          *    are dirty
 173          * 2) we've read the full bitmap, in which case we ignore any trailing
 174          *    data in the file
 175          */
 176         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 177
 178         while(read_bits < total_bits) {
 179                 unsigned long long remaining = total_bits - read_bits;
 180
 181                 if (n == 0) {
 182                         n = read(fd, buf, 8192);
 183                         skip = 0;
 184                         if (n <= 0)
 185                                 break;
 186                 }
 187                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 188                         remaining = (n-skip) * 8;
 189
 190                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 191
 192                 read_bits += remaining;
 193                 n = 0;
 194         }
 195
 196         if (read_bits < total_bits) { /* file truncated... */
 197                 fprintf(stderr, Name ": WARNING: bitmap file is not large "
 198                         "enough for array size %llu!\n\n",
 199                         (unsigned long long)info->sb.sync_size);
 200                 total_bits = read_bits;
 201         }
 202 out:
 203         info->total_bits = total_bits;
 204         info->dirty_bits = dirty_bits;
 205         return info;
 206 }
 207
 208 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 209 {
 210         int fd;
 211         bitmap_info_t *info;
 212         struct stat stb;
 213         struct supertype *st = *stp;
 214
 215         if (stat(filename, &stb) < 0) {
 216                 fprintf(stderr, Name ": failed to find file %s: %s\n",
 217                         filename, strerror(errno));
 218                 return NULL;
 219         }
 220         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 221                 fd = open(filename, O_RDONLY);
 222                 if (fd < 0) {
 223                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 224                                 filename, strerror(errno));
 225                         return NULL;
 226                 }
 227                 /* block device, so we are probably after an internal bitmap */
 228                 if (!st) st = guess_super(fd);
 229                 if (!st) {
 230                         /* just look at device... */
 231                         lseek(fd, 0, 0);
 232                 } else {
 233                         st->ss->locate_bitmap(st, fd);
 234                 }
 235                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 236                 *stp = st;
 237         } else {
 238                 fd = open(filename, O_RDONLY|O_DIRECT);
 239                 if (fd < 0) {
 240                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 241                                 filename, strerror(errno));
 242                         return NULL;
 243                 }
 244         }
 245
 246         info = bitmap_fd_read(fd, brief);
 247         close(fd);
 248         return info;
 249 }
 250
 251 __u32 swapl(__u32 l)
 252 {
 253         char *c = (char*)&l;
 254         char t= c[0];
 255         c[0] = c[3];
 256         c[3] = t;
 257
 258         t = c[1];
 259         c[1] = c[2];
 260         c[2] = t;
 261         return l;
 262 }
 263 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 264 {
 265         /*
 266          * Read the bitmap file and display its contents
 267          */
 268
 269         bitmap_super_t *sb;
 270         bitmap_info_t *info;
 271         int rv = 1;
 272         char buf[64];
 273         int swap;
 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         if (swap) {
 302         printf("            UUID : %08x:%08x:%08x:%08x\n",
 303                                         swapl(*(__u32 *)(sb->uuid+0)),
 304                                         swapl(*(__u32 *)(sb->uuid+4)),
 305                                         swapl(*(__u32 *)(sb->uuid+8)),
 306                                         swapl(*(__u32 *)(sb->uuid+12)));
 307         } else {
 308         printf("            UUID : %08x:%08x:%08x:%08x\n",
 309                                         *(__u32 *)(sb->uuid+0),
 310                                         *(__u32 *)(sb->uuid+4),
 311                                         *(__u32 *)(sb->uuid+8),
 312                                         *(__u32 *)(sb->uuid+12));
 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 }