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  46         { "Out of date", 2 },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 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 119 {
 120         /* Note: fd might be open O_DIRECT, so we must be
 121          * careful to align reads properly
 122          */
 123         unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
 124         bitmap_info_t *info;
 125         void *buf;
 126         int n, skip;
 127
 128         if (posix_memalign(&buf, 512, 8192) != 0) {
 129                 fprintf(stderr, Name ": failed to allocate 8192 bytes\n");
 130                 return NULL;
 131         }
 132         n = read(fd, buf, 8192);
 133
 134         info = malloc(sizeof(*info));
 135         if (info == NULL) {
 136 #if __GNUC__ < 3
 137                 fprintf(stderr, Name ": failed to allocate %d bytes\n",
 138                                 (int)sizeof(*info));
 139 #else
 140                 fprintf(stderr, Name ": failed to allocate %zd bytes\n",
 141                                 sizeof(*info));
 142 #endif
 143                 return NULL;
 144         }
 145
 146         if (n < sizeof(info->sb)) {
 147                 fprintf(stderr, Name ": failed to read superblock of bitmap "
 148                         "file: %s\n", strerror(errno));
 149                 free(info);
 150                 return NULL;
 151         }
 152         memcpy(&info->sb, buf, sizeof(info->sb));
 153         skip = sizeof(info->sb);
 154
 155         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 156
 157         if (brief || info->sb.sync_size == 0)
 158                 goto out;
 159
 160         /* read the rest of the file counting total bits and dirty bits --
 161          * we stop when either:
 162          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 163          *    are dirty
 164          * 2) we've read the full bitmap, in which case we ignore any trailing
 165          *    data in the file
 166          */
 167         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 168
 169         while(read_bits < total_bits) {
 170                 unsigned long long remaining = total_bits - read_bits;
 171
 172                 if (n == 0) {
 173                         n = read(fd, buf, 8192);
 174                         skip = 0;
 175                         if (n <= 0)
 176                                 break;
 177                 }
 178                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 179                         remaining = (n-skip) * 8;
 180
 181                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 182
 183                 read_bits += remaining;
 184                 n = 0;
 185         }
 186
 187         if (read_bits < total_bits) { /* file truncated... */
 188                 fprintf(stderr, Name ": WARNING: bitmap file is not large "
 189                         "enough for array size %llu!\n\n",
 190                         (unsigned long long)info->sb.sync_size);
 191                 total_bits = read_bits;
 192         }
 193 out:
 194         info->total_bits = total_bits;
 195         info->dirty_bits = dirty_bits;
 196         return info;
 197 }
 198
 199 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 200 {
 201         int fd;
 202         bitmap_info_t *info;
 203         struct stat stb;
 204         struct supertype *st = *stp;
 205
 206         if (stat(filename, &stb) < 0) {
 207                 fprintf(stderr, Name ": failed to find file %s: %s\n",
 208                         filename, strerror(errno));
 209                 return NULL;
 210         }
 211         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 212                 fd = open(filename, O_RDONLY);
 213                 if (fd < 0) {
 214                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 215                                 filename, strerror(errno));
 216                         return NULL;
 217                 }
 218                 /* block device, so we are probably after an internal bitmap */
 219                 if (!st) st = guess_super(fd);
 220                 if (!st) {
 221                         /* just look at device... */
 222                         lseek(fd, 0, 0);
 223                 } else {
 224                         st->ss->locate_bitmap(st, fd);
 225                 }
 226                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 227                 *stp = st;
 228         } else {
 229                 fd = open(filename, O_RDONLY|O_DIRECT);
 230                 if (fd < 0) {
 231                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 232                                 filename, strerror(errno));
 233                         return NULL;
 234                 }
 235         }
 236
 237         info = bitmap_fd_read(fd, brief);
 238         close(fd);
 239         return info;
 240 }
 241
 242 __u32 swapl(__u32 l)
 243 {
 244         char *c = (char*)&l;
 245         char t= c[0];
 246         c[0] = c[3];
 247         c[3] = t;
 248
 249         t = c[1];
 250         c[1] = c[2];
 251         c[2] = t;
 252         return l;
 253 }
 254 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 255 {
 256         /*
 257          * Read the bitmap file and display its contents
 258          */
 259
 260         bitmap_super_t *sb;
 261         bitmap_info_t *info;
 262         int rv = 1;
 263         char buf[64];
 264         int swap;
 265
 266         info = bitmap_file_read(filename, brief, &st);
 267         if (!info)
 268                 return rv;
 269
 270         sb = &info->sb;
 271         printf("        Filename : %s\n", filename);
 272         printf("           Magic : %08x\n", sb->magic);
 273         if (sb->magic != BITMAP_MAGIC) {
 274                 fprintf(stderr, Name ": invalid bitmap magic 0x%x, the bitmap file appears to be corrupted\n", sb->magic);
 275         }
 276         printf("         Version : %d\n", sb->version);
 277         if (sb->version < BITMAP_MAJOR_LO ||
 278             sb->version > BITMAP_MAJOR_HI) {
 279                 fprintf(stderr, Name ": unknown bitmap version %d, either the bitmap file is corrupted or you need to upgrade your tools\n", sb->version);
 280                 goto free_info;
 281         }
 282
 283         rv = 0;
 284         if (st)
 285                 swap = st->ss->swapuuid;
 286         else
 287 #if __BYTE_ORDER == BIG_ENDIAN
 288                 swap = 0;
 289 #else
 290                 swap = 1;
 291 #endif
 292         if (swap) {
 293         printf("            UUID : %08x:%08x:%08x:%08x\n",
 294                                         swapl(*(__u32 *)(sb->uuid+0)),
 295                                         swapl(*(__u32 *)(sb->uuid+4)),
 296                                         swapl(*(__u32 *)(sb->uuid+8)),
 297                                         swapl(*(__u32 *)(sb->uuid+12)));
 298         } else {
 299         printf("            UUID : %08x:%08x:%08x:%08x\n",
 300                                         *(__u32 *)(sb->uuid+0),
 301                                         *(__u32 *)(sb->uuid+4),
 302                                         *(__u32 *)(sb->uuid+8),
 303                                         *(__u32 *)(sb->uuid+12));
 304         }
 305         printf("          Events : %llu\n", (unsigned long long)sb->events);
 306         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 307         printf("           State : %s\n", bitmap_state(sb->state));
 308         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 309         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 310         if (sb->write_behind)
 311                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 312         else
 313                 sprintf(buf, "Normal");
 314         printf("      Write Mode : %s\n", buf);
 315         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 316                                         human_size(sb->sync_size * 512));
 317         if (brief)
 318                 goto free_info;
 319         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 320                         info->total_bits, info->dirty_bits,
 321                         100.0 * info->dirty_bits / (info->total_bits + 1));
 322 free_info:
 323         free(info);
 324         return rv;
 325 }
 326
 327 int CreateBitmap(char *filename, int force, char uuid[16],
 328                  unsigned long chunksize, unsigned long daemon_sleep,
 329                  unsigned long write_behind,
 330                  unsigned long long array_size /* sectors */,
 331                  int major)
 332 {
 333         /*
 334          * Create a bitmap file with a superblock and (optionally) a full bitmap
 335          */
 336
 337         FILE *fp;
 338         int rv = 1;
 339         char block[512];
 340         bitmap_super_t sb;
 341         long long bytes, filesize;
 342
 343         if (!force && access(filename, F_OK) == 0) {
 344                 fprintf(stderr, Name ": bitmap file %s already exists, use --force to overwrite\n", filename);
 345                 return rv;
 346         }
 347
 348         fp = fopen(filename, "w");
 349         if (fp == NULL) {
 350                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 351                         filename, strerror(errno));
 352                 return rv;
 353         }
 354
 355         if (chunksize == UnSet) {
 356                 /* We don't want more than 2^21 chunks, as 2^11 fill up one
 357                  * 4K page (2 bytes per chunk), and 2^10 address of those
 358                  * fill up a 4K indexing page.  2^20 might be safer, especially
 359                  * on 64bit hosts, so use that.
 360                  */
 361                 chunksize = DEFAULT_BITMAP_CHUNK;
 362                 /* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
 363                 while (array_size > (chunksize << (20-9)))
 364                         chunksize <<= 1;
 365         }
 366
 367         memset(&sb, 0, sizeof(sb));
 368         sb.magic = BITMAP_MAGIC;
 369         sb.version = major;
 370         if (uuid != NULL)
 371                 memcpy(sb.uuid, uuid, 16);
 372         sb.chunksize = chunksize;
 373         sb.daemon_sleep = daemon_sleep;
 374         sb.write_behind = write_behind;
 375         sb.sync_size = array_size;
 376
 377         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 378
 379         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 380                 fprintf(stderr, Name ": failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 381                 goto out;
 382         }
 383
 384         /* calculate the size of the bitmap and write it to disk */
 385         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 386         if (!bytes) {
 387                 rv = 0;
 388                 goto out;
 389         }
 390
 391         filesize = bytes + sizeof(sb);
 392
 393         memset(block, 0xff, sizeof(block));
 394
 395         while (bytes > 0) {
 396                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 397                         fprintf(stderr, Name ": failed to write bitmap file %s: %s\n", filename, strerror(errno));
 398                         goto out;
 399                 }
 400                 bytes -= sizeof(block);
 401         }
 402
 403         rv = 0;
 404         fflush(fp);
 405         /* make the file be the right size (well, to the nearest byte) */
 406         if (ftruncate(fileno(fp), filesize))
 407                 perror("ftrunace");
 408 out:
 409         fclose(fp);
 410         if (rv)
 411                 unlink(filename); /* possibly corrupted, better get rid of it */
 412         return rv;
 413 }
 414
 415 int bitmap_update_uuid(int fd, int *uuid, int swap)
 416 {
 417         struct bitmap_super_s bm;
 418         if (lseek(fd, 0, 0) != 0)
 419                 return 1;
 420         if (read(fd, &bm, sizeof(bm)) != sizeof(bm))
 421                 return 1;
 422         if (bm.magic != __cpu_to_le32(BITMAP_MAGIC))
 423                 return 1;
 424         copy_uuid(bm.uuid, uuid, swap);
 425         if (lseek(fd, 0, 0) != 0)
 426                 return 2;
 427         if (write(fd, &bm, sizeof(bm)) != sizeof(bm)) {
 428                 lseek(fd, 0, 0);
 429                 return 2;
 430         }
 431         lseek(fd, 0, 0);
 432         return 0;
 433 }