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  44         { "Out of date", 2 },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 "
 144                        "file: %s\n", strerror(errno));
 145                 free(info);
 146                 free(buf);
 147                 return NULL;
 148         }
 149         memcpy(&info->sb, buf, sizeof(info->sb));
 150         skip = sizeof(info->sb);
 151
 152         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 153
 154         if (brief || info->sb.sync_size == 0 || info->sb.chunksize == 0)
 155                 goto out;
 156
 157         /* read the rest of the file counting total bits and dirty bits --
 158          * we stop when either:
 159          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 160          *    are dirty
 161          * 2) we've read the full bitmap, in which case we ignore any trailing
 162          *    data in the file
 163          */
 164         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 165
 166         while(read_bits < total_bits) {
 167                 unsigned long long remaining = total_bits - read_bits;
 168
 169                 if (n == 0) {
 170                         n = read(fd, buf, 8192);
 171                         skip = 0;
 172                         if (n <= 0)
 173                                 break;
 174                 }
 175                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 176                         remaining = (n-skip) * 8;
 177
 178                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 179
 180                 read_bits += remaining;
 181                 n = 0;
 182         }
 183
 184         if (read_bits < total_bits) { /* file truncated... */
 185                 pr_err("WARNING: bitmap file is not large "
 186                         "enough for array size %llu!\n\n",
 187                         (unsigned long long)info->sb.sync_size);
 188                 total_bits = read_bits;
 189         }
 190 out:
 191         free(buf);
 192         info->total_bits = total_bits;
 193         info->dirty_bits = dirty_bits;
 194         return info;
 195 }
 196
 197 int bitmap_file_open(char *filename, struct supertype **stp)
 198 {
 199         int fd;
 200         struct stat stb;
 201         struct supertype *st = *stp;
 202
 203         if (stat(filename, &stb) < 0) {
 204                 pr_err("failed to find file %s: %s\n",
 205                         filename, strerror(errno));
 206                 return -1;
 207         }
 208         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 209                 fd = open(filename, O_RDONLY|O_DIRECT);
 210                 if (fd < 0) {
 211                         pr_err("failed to open bitmap file %s: %s\n",
 212                                 filename, strerror(errno));
 213                         return -1;
 214                 }
 215                 /* block device, so we are probably after an internal bitmap */
 216                 if (!st) st = guess_super(fd);
 217                 if (!st) {
 218                         /* just look at device... */
 219                         lseek(fd, 0, 0);
 220                 } else if (!st->ss->locate_bitmap) {
 221                         pr_err("No bitmap possible with %s metadata\n",
 222                                 st->ss->name);
 223                         return -1;
 224                 } else
 225                         st->ss->locate_bitmap(st, fd);
 226
 227                 *stp = st;
 228         } else {
 229                 fd = open(filename, O_RDONLY|O_DIRECT);
 230                 if (fd < 0) {
 231                         pr_err("failed to open bitmap file %s: %s\n",
 232                                 filename, strerror(errno));
 233                         return -1;
 234                 }
 235         }
 236
 237         return fd;
 238 }
 239
 240 __u32 swapl(__u32 l)
 241 {
 242         char *c = (char*)&l;
 243         char t= c[0];
 244         c[0] = c[3];
 245         c[3] = t;
 246
 247         t = c[1];
 248         c[1] = c[2];
 249         c[2] = t;
 250         return l;
 251 }
 252 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 253 {
 254         /*
 255          * Read the bitmap file and display its contents
 256          */
 257
 258         bitmap_super_t *sb;
 259         bitmap_info_t *info;
 260         int rv = 1;
 261         char buf[64];
 262         int swap;
 263         int fd;
 264         __u32 uuid32[4];
 265
 266         fd = bitmap_file_open(filename, &st);
 267         if (fd < 0)
 268                 return rv;
 269
 270         info = bitmap_fd_read(fd, brief);
 271         if (!info)
 272                 return rv;
 273         sb = &info->sb;
 274         if (sb->magic != BITMAP_MAGIC && md_get_version(fd) > 0) {
 275                 pr_err("This is an md array.  To view a bitmap you need to examine\n");
 276                 pr_err("a member device, not the array.\n");
 277                 pr_err("Reporting bitmap that would be used if this array were used\n");
 278                 pr_err("as a member of some other array\n");
 279         }
 280         close(fd);
 281         printf("        Filename : %s\n", filename);
 282         printf("           Magic : %08x\n", sb->magic);
 283         if (sb->magic != BITMAP_MAGIC) {
 284                 pr_err("invalid bitmap magic 0x%x, the bitmap file appears\n",
 285                        sb->magic);
 286                 pr_err("to be corrupted or missing.\n");
 287         }
 288         printf("         Version : %d\n", sb->version);
 289         if (sb->version < BITMAP_MAJOR_LO ||
 290             sb->version > BITMAP_MAJOR_HI) {
 291                 pr_err("unknown bitmap version %d, either the bitmap file\n",
 292                        sb->version);
 293                 pr_err("is corrupted or you need to upgrade your tools\n");
 294                 goto free_info;
 295         }
 296
 297         rv = 0;
 298         if (st)
 299                 swap = st->ss->swapuuid;
 300         else
 301 #if __BYTE_ORDER == BIG_ENDIAN
 302                 swap = 0;
 303 #else
 304                 swap = 1;
 305 #endif
 306         memcpy(uuid32, sb->uuid, 16);
 307         if (swap)
 308                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 309                        swapl(uuid32[0]),
 310                        swapl(uuid32[1]),
 311                        swapl(uuid32[2]),
 312                        swapl(uuid32[3]));
 313         else
 314                 printf("            UUID : %08x:%08x:%08x:%08x\n",
 315                        uuid32[0],
 316                        uuid32[1],
 317                        uuid32[2],
 318                        uuid32[3]);
 319
 320         printf("          Events : %llu\n", (unsigned long long)sb->events);
 321         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 322         printf("           State : %s\n", bitmap_state(sb->state));
 323         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 324         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 325         if (sb->write_behind)
 326                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 327         else
 328                 sprintf(buf, "Normal");
 329         printf("      Write Mode : %s\n", buf);
 330         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 331                                         human_size(sb->sync_size * 512));
 332         if (brief)
 333                 goto free_info;
 334         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 335                         info->total_bits, info->dirty_bits,
 336                         100.0 * info->dirty_bits / (info->total_bits?:1));
 337 free_info:
 338         free(info);
 339         return rv;
 340 }
 341
 342 int CreateBitmap(char *filename, int force, char uuid[16],
 343                  unsigned long chunksize, unsigned long daemon_sleep,
 344                  unsigned long write_behind,
 345                  unsigned long long array_size /* sectors */,
 346                  int major)
 347 {
 348         /*
 349          * Create a bitmap file with a superblock and (optionally) a full bitmap
 350          */
 351
 352         FILE *fp;
 353         int rv = 1;
 354         char block[512];
 355         bitmap_super_t sb;
 356         long long bytes, filesize;
 357
 358         if (!force && access(filename, F_OK) == 0) {
 359                 pr_err("bitmap file %s already exists, use --force to overwrite\n", filename);
 360                 return rv;
 361         }
 362
 363         fp = fopen(filename, "w");
 364         if (fp == NULL) {
 365                 pr_err("failed to open bitmap file %s: %s\n",
 366                         filename, strerror(errno));
 367                 return rv;
 368         }
 369
 370         if (chunksize == UnSet) {
 371                 /* We don't want more than 2^21 chunks, as 2^11 fill up one
 372                  * 4K page (2 bytes per chunk), and 2^10 address of those
 373                  * fill up a 4K indexing page.  2^20 might be safer, especially
 374                  * on 64bit hosts, so use that.
 375                  */
 376                 chunksize = DEFAULT_BITMAP_CHUNK;
 377                 /* <<20 for 2^20 chunks, >>9 to convert bytes to sectors */
 378                 while (array_size > ((unsigned long long)chunksize << (20-9)))
 379                         chunksize <<= 1;
 380         }
 381
 382         memset(&sb, 0, sizeof(sb));
 383         sb.magic = BITMAP_MAGIC;
 384         sb.version = major;
 385         if (uuid != NULL)
 386                 memcpy(sb.uuid, uuid, 16);
 387         sb.chunksize = chunksize;
 388         sb.daemon_sleep = daemon_sleep;
 389         sb.write_behind = write_behind;
 390         sb.sync_size = array_size;
 391
 392         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 393
 394         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 395                 pr_err("failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 396                 goto out;
 397         }
 398
 399         /* calculate the size of the bitmap and write it to disk */
 400         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 401         if (!bytes) {
 402                 rv = 0;
 403                 goto out;
 404         }
 405
 406         filesize = bytes + sizeof(sb);
 407
 408         memset(block, 0xff, sizeof(block));
 409
 410         while (bytes > 0) {
 411                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 412                         pr_err("failed to write bitmap file %s: %s\n", filename, strerror(errno));
 413                         goto out;
 414                 }
 415                 bytes -= sizeof(block);
 416         }
 417
 418         rv = 0;
 419         fflush(fp);
 420         /* make the file be the right size (well, to the nearest byte) */
 421         if (ftruncate(fileno(fp), filesize))
 422                 perror("ftrunace");
 423 out:
 424         fclose(fp);
 425         if (rv)
 426                 unlink(filename); /* possibly corrupted, better get rid of it */
 427         return rv;
 428 }
 429
 430 int bitmap_update_uuid(int fd, int *uuid, int swap)
 431 {
 432         struct bitmap_super_s bm;
 433         if (lseek(fd, 0, 0) != 0)
 434                 return 1;
 435         if (read(fd, &bm, sizeof(bm)) != sizeof(bm))
 436                 return 1;
 437         if (bm.magic != __cpu_to_le32(BITMAP_MAGIC))
 438                 return 1;
 439         copy_uuid(bm.uuid, uuid, swap);
 440         if (lseek(fd, 0, 0) != 0)
 441                 return 2;
 442         if (write(fd, &bm, sizeof(bm)) != sizeof(bm)) {
 443                 lseek(fd, 0, 0);
 444                 return 2;
 445         }
 446         lseek(fd, 0, 0);
 447         return 0;
 448 }