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  44         { "Out of date", 2 },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 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 125 {
 126         /* Note: fd might be open O_DIRECT, so we must be
 127          * careful to align reads properly
 128          */
 129         unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
 130         bitmap_info_t *info;
 131         void *buf;
 132         unsigned int n, skip;
 133
 134         if (posix_memalign(&buf, 4096, 8192) != 0) {
 135                 pr_err("failed to allocate 8192 bytes\n");
 136                 return NULL;
 137         }
 138         n = read(fd, buf, 8192);
 139
 140         info = xmalloc(sizeof(*info));
 141
 142         if (n < sizeof(info->sb)) {
 143                 pr_err("failed to read superblock of bitmap file: %s\n", strerror(errno));
 144                 free(info);
 145                 free(buf);
 146                 return NULL;
 147         }
 148         memcpy(&info->sb, buf, sizeof(info->sb));
 149         skip = sizeof(info->sb);
 150
 151         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 152
 153         if (brief || info->sb.sync_size == 0 || info->sb.chunksize == 0)
 154                 goto out;
 155
 156         /* read the rest of the file counting total bits and dirty bits --
 157          * we stop when either:
 158          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 159          *    are dirty
 160          * 2) we've read the full bitmap, in which case we ignore any trailing
 161          *    data in the file
 162          */
 163         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 164
 165         while(read_bits < total_bits) {
 166                 unsigned long long remaining = total_bits - read_bits;
 167
 168                 if (n == 0) {
 169                         n = read(fd, buf, 8192);
 170                         skip = 0;
 171                         if (n <= 0)
 172                                 break;
 173                 }
 174                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 175                         remaining = (n-skip) * 8;
 176
 177                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 178
 179                 read_bits += remaining;
 180                 n = 0;
 181         }
 182
 183         if (read_bits < total_bits) { /* file truncated... */
 184                 pr_err("WARNING: bitmap file is not large enough for array size %llu!\n\n",
 185                         (unsigned long long)info->sb.sync_size);
 186                 total_bits = read_bits;
 187         }
 188 out:
 189         free(buf);
 190         info->total_bits = total_bits;
 191         info->dirty_bits = dirty_bits;
 192         return info;
 193 }
 194
 195 int bitmap_file_open(char *filename, struct supertype **stp)
 196 {
 197         int fd;
 198         struct stat stb;
 199         struct supertype *st = *stp;
 200
 201         if (stat(filename, &stb) < 0) {
 202                 pr_err("failed to find file %s: %s\n",
 203                         filename, strerror(errno));
 204                 return -1;
 205         }
 206         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 207                 fd = open(filename, O_RDONLY|O_DIRECT);
 208                 if (fd < 0) {
 209                         pr_err("failed to open bitmap file %s: %s\n",
 210                                 filename, strerror(errno));
 211                         return -1;
 212                 }
 213                 /* block device, so we are probably after an internal bitmap */
 214                 if (!st) st = guess_super(fd);
 215                 if (!st) {
 216                         /* just look at device... */
 217                         lseek(fd, 0, 0);
 218                 } else if (!st->ss->locate_bitmap) {
 219                         pr_err("No bitmap possible with %s metadata\n",
 220                                 st->ss->name);
 221                         return -1;
 222                 } else
 223                         st->ss->locate_bitmap(st, fd);
 224
 225                 *stp = st;
 226         } else {
 227                 fd = open(filename, O_RDONLY|O_DIRECT);
 228                 if (fd < 0) {
 229                         pr_err("failed to open bitmap file %s: %s\n",
 230                                 filename, strerror(errno));
 231                         return -1;
 232                 }
 233         }
 234
 235         return fd;
 236 }
 237
 238 __u32 swapl(__u32 l)
 239 {
 240         char *c = (char*)&l;
 241         char t= c[0];
 242         c[0] = c[3];
 243         c[3] = t;
 244
 245         t = c[1];
 246         c[1] = c[2];
 247         c[2] = t;
 248         return l;
 249 }
 250 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 251 {
 252         /*
 253          * Read the bitmap file and display its contents
 254          */
 255
 256         bitmap_super_t *sb;
 257         bitmap_info_t *info;
 258         int rv = 1;
 259         char buf[64];
 260         int swap;
 261         int fd;
 262         __u32 uuid32[4];
 263
 264         fd = bitmap_file_open(filename, &st);
 265         if (fd < 0)
 266                 return rv;
 267
 268         info = bitmap_fd_read(fd, brief);
 269         if (!info)
 270                 return rv;
 271         sb = &info->sb;
 272         if (sb->magic != BITMAP_MAGIC && md_get_version(fd) > 0) {
 273                 pr_err("This is an md array.  To view a bitmap you need to examine\n");
 274                 pr_err("a member device, not the array.\n");
 275                 pr_err("Reporting bitmap that would be used if this array were used\n");
 276                 pr_err("as a member of some other array\n");
 277         }
 278         close(fd);
 279         printf("        Filename : %s\n", filename);
 280         printf("           Magic : %08x\n", sb->magic);
 281         if (sb->magic != BITMAP_MAGIC) {
 282                 pr_err("invalid bitmap magic 0x%x, the bitmap file appears\n",
 283                        sb->magic);
 284                 pr_err("to be corrupted or missing.\n");
 285         }
 286         printf("         Version : %d\n", sb->version);
 287         if (sb->version < BITMAP_MAJOR_LO ||
 288             sb->version > BITMAP_MAJOR_HI) {
 289                 pr_err("unknown bitmap version %d, either the bitmap file\n",
 290                        sb->version);
 291                 pr_err("is corrupted or you need to upgrade your tools\n");
 292                 goto free_info;
 293         }
 294
 295         rv = 0;
 296         if (st)
 297                 swap = st->ss->swapuuid;
 298         else
 299 #if __BYTE_ORDER == BIG_ENDIAN
 300                 swap = 0;
 301 #else
 302                 swap = 1;
 303 #endif
 304         memcpy(uuid32, sb->uuid, 16);
 305         if (swap)
 306                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 307                        swapl(uuid32[0]),
 308                        swapl(uuid32[1]),
 309                        swapl(uuid32[2]),
 310                        swapl(uuid32[3]));
 311         else
 312                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 313                        uuid32[0],
 314                        uuid32[1],
 315                        uuid32[2],
 316                        uuid32[3]);
 317
 318         printf("          Events : %llu\n", (unsigned long long)sb->events);
 319         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 320         printf("           State : %s\n", bitmap_state(sb->state));
 321         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 322         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 323         if (sb->write_behind)
 324                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 325         else
 326                 sprintf(buf, "Normal");
 327         printf("      Write Mode : %s\n", buf);
 328         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 329                                         human_size(sb->sync_size * 512));
 330         if (brief)
 331                 goto free_info;
 332         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 333                         info->total_bits, info->dirty_bits,
 334                         100.0 * info->dirty_bits / (info->total_bits?:1));
 335 free_info:
 336         free(info);
 337         return rv;
 338 }
 339
 340 int CreateBitmap(char *filename, int force, char uuid[16],
 341                  unsigned long chunksize, unsigned long daemon_sleep,
 342                  unsigned long write_behind,
 343                  unsigned long long array_size /* sectors */,
 344                  int major)
 345 {
 346         /*
 347          * Create a bitmap file with a superblock and (optionally) a full bitmap
 348          */
 349
 350         FILE *fp;
 351         int rv = 1;
 352         char block[512];
 353         bitmap_super_t sb;
 354         long long bytes, filesize;
 355
 356         if (!force && access(filename, F_OK) == 0) {
 357                 pr_err("bitmap file %s already exists, use --force to overwrite\n", filename);
 358                 return rv;
 359         }
 360
 361         fp = fopen(filename, "w");
 362         if (fp == NULL) {
 363                 pr_err("failed to open bitmap file %s: %s\n",
 364                         filename, strerror(errno));
 365                 return rv;
 366         }
 367
 368         if (chunksize == UnSet) {
 369                 /* We don't want more than 2^21 chunks, as 2^11 fill up one
 370                  * 4K page (2 bytes per chunk), and 2^10 address of those
 371                  * fill up a 4K indexing page.  2^20 might be safer, especially
 372                  * on 64bit hosts, so use that.
 373                  */
 374                 chunksize = DEFAULT_BITMAP_CHUNK;
 375                 /* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
 376                 while (array_size > ((unsigned long long)chunksize << (20-9)))
 377                         chunksize <<= 1;
 378         }
 379
 380         memset(&sb, 0, sizeof(sb));
 381         sb.magic = BITMAP_MAGIC;
 382         sb.version = major;
 383         if (uuid != NULL)
 384                 memcpy(sb.uuid, uuid, 16);
 385         sb.chunksize = chunksize;
 386         sb.daemon_sleep = daemon_sleep;
 387         sb.write_behind = write_behind;
 388         sb.sync_size = array_size;
 389
 390         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 391
 392         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 393                 pr_err("failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 394                 goto out;
 395         }
 396
 397         /* calculate the size of the bitmap and write it to disk */
 398         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 399         if (!bytes) {
 400                 rv = 0;
 401                 goto out;
 402         }
 403
 404         filesize = bytes + sizeof(sb);
 405
 406         memset(block, 0xff, sizeof(block));
 407
 408         while (bytes > 0) {
 409                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 410                         pr_err("failed to write bitmap file %s: %s\n", filename, strerror(errno));
 411                         goto out;
 412                 }
 413                 bytes -= sizeof(block);
 414         }
 415
 416         rv = 0;
 417         fflush(fp);
 418         /* make the file be the right size (well, to the nearest byte) */
 419         if (ftruncate(fileno(fp), filesize))
 420                 perror("ftrunace");
 421 out:
 422         fclose(fp);
 423         if (rv)
 424                 unlink(filename); /* possibly corrupted, better get rid of it */
 425         return rv;
 426 }
 427
 428 int bitmap_update_uuid(int fd, int *uuid, int swap)
 429 {
 430         struct bitmap_super_s bm;
 431         if (lseek(fd, 0, 0) != 0)
 432                 return 1;
 433         if (read(fd, &bm, sizeof(bm)) != sizeof(bm))
 434                 return 1;
 435         if (bm.magic != __cpu_to_le32(BITMAP_MAGIC))
 436                 return 1;
 437         copy_uuid(bm.uuid, uuid, swap);
 438         if (lseek(fd, 0, 0) != 0)
 439                 return 2;
 440         if (write(fd, &bm, sizeof(bm)) != sizeof(bm)) {
 441                 lseek(fd, 0, 0);
 442                 return 2;
 443         }
 444         lseek(fd, 0, 0);
 445         return 0;
 446 }