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  46         { "Out of date", 2 },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