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 }
  37
  38 inline void sb_cpu_to_le(bitmap_super_t *sb)
  39 {
  40         sb_le_to_cpu(sb); /* these are really the same thing */
  41 }
  42
  43 mapping_t bitmap_states[] = {
  44         { "OK", 0 },
  45         { "Out of date", 2 },
  46         { NULL, -1 }
  47 };
  48
  49 const char *bitmap_state(int state_num)
  50 {
  51         char *state = map_num(bitmap_states, state_num);
  52         return state ? state : "Unknown";
  53 }
  54
  55 const char *human_chunksize(unsigned long bytes)
  56 {
  57         static char buf[16];
  58         char *suffixes[] = { "B", "KB", "MB", "GB", "TB", NULL };
  59         int i = 0;
  60
  61         while (bytes >> 10) {
  62                 bytes >>= 10;
  63                 i++;
  64         }
  65
  66         snprintf(buf, sizeof(buf), "%lu %s", bytes, suffixes[i]);
  67
  68         return buf;
  69 }
  70
  71 typedef struct bitmap_info_s {
  72         bitmap_super_t sb;
  73         unsigned long long total_bits;
  74         unsigned long long dirty_bits;
  75 } bitmap_info_t;
  76
  77 /* count the dirty bits in the first num_bits of byte */
  78 inline int count_dirty_bits_byte(char byte, int num_bits)
  79 {
  80         int num = 0;
  81
  82         switch (num_bits) { /* fall through... */
  83                 case 8: if (byte & 128) num++;
  84                 case 7: if (byte &  64) num++;
  85                 case 6: if (byte &  32) num++;
  86                 case 5: if (byte &  16) num++;
  87                 case 4: if (byte &   8) num++;
  88                 case 3: if (byte &   4) num++;
  89                 case 2: if (byte &   2) num++;
  90                 case 1: if (byte &   1) num++;
  91                 default: break;
  92         }
  93
  94         return num;
  95 }
  96
  97 int count_dirty_bits(char *buf, int num_bits)
  98 {
  99         int i, num = 0;
 100
 101         for (i=0; i < num_bits / 8; i++)
 102                 num += count_dirty_bits_byte(buf[i], 8);
 103
 104         if (num_bits % 8) /* not an even byte boundary */
 105                 num += count_dirty_bits_byte(buf[i], num_bits % 8);
 106
 107         return num;
 108 }
 109
 110 /* calculate the size of the bitmap given the array size and bitmap chunksize */
 111 unsigned long long bitmap_bits(unsigned long long array_size,
 112                                 unsigned long chunksize)
 113 {
 114         return (array_size * 512 + chunksize - 1) / chunksize;
 115 }
 116
 117 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 118 {
 119         /* Note: fd might be open O_DIRECT, so we must be
 120          * careful to align reads properly
 121          */
 122         unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
 123         bitmap_info_t *info;
 124         char *buf, *unaligned;
 125         int n, skip;
 126
 127         unaligned = malloc(8192*2);
 128         buf = (char*) ((unsigned long)unaligned | 8191)+1;
 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                 free(unaligned);
 148                 return NULL;
 149         }
 150         memcpy(&info->sb, buf, sizeof(info->sb));
 151         skip = sizeof(info->sb);
 152
 153         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 154
 155         if (brief || info->sb.sync_size == 0)
 156                 goto out;
 157
 158         /* read the rest of the file counting total bits and dirty bits --
 159          * we stop when either:
 160          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 161          *    are dirty
 162          * 2) we've read the full bitmap, in which case we ignore any trailing
 163          *    data in the file
 164          */
 165         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 166
 167         while(read_bits < total_bits) {
 168                 unsigned long long remaining = total_bits - read_bits;
 169
 170                 if (n == 0) {
 171                         n = read(fd, buf, 8192);
 172                         skip = 0;
 173                         if (n <= 0)
 174                                 break;
 175                 }
 176                 if (remaining > (n-skip) * 8) /* we want the full buffer */
 177                         remaining = (n-skip) * 8;
 178
 179                 dirty_bits += count_dirty_bits(buf+skip, remaining);
 180
 181                 read_bits += remaining;
 182                 n = 0;
 183         }
 184
 185         if (read_bits < total_bits) { /* file truncated... */
 186                 fprintf(stderr, Name ": WARNING: bitmap file is not large "
 187                         "enough for array size %llu!\n\n",
 188                         (unsigned long long)info->sb.sync_size);
 189                 total_bits = read_bits;
 190         }
 191 out:
 192         info->total_bits = total_bits;
 193         info->dirty_bits = dirty_bits;
 194         return info;
 195 }
 196
 197 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 198 {
 199         int fd;
 200         bitmap_info_t *info;
 201         struct stat stb;
 202         struct supertype *st = *stp;
 203
 204         if (stat(filename, &stb) < 0) {
 205                 fprintf(stderr, Name ": failed to find file %s: %s\n",
 206                         filename, strerror(errno));
 207                 return NULL;
 208         }
 209         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 210                 fd = open(filename, O_RDONLY);
 211                 if (fd < 0) {
 212                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 213                                 filename, strerror(errno));
 214                         return NULL;
 215                 }
 216                 /* block device, so we are probably after an internal bitmap */
 217                 if (!st) st = guess_super(fd);
 218                 if (!st) {
 219                         /* just look at device... */
 220                         lseek(fd, 0, 0);
 221                 } else {
 222                         st->ss->locate_bitmap(st, fd, NULL);
 223                 }
 224                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 225                 *stp = st;
 226         } else {
 227                 fd = open(filename, O_RDONLY|O_DIRECT);
 228                 if (fd < 0) {
 229                         fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 230                                 filename, strerror(errno));
 231                         return NULL;
 232                 }
 233         }
 234
 235         info = bitmap_fd_read(fd, brief);
 236         close(fd);
 237         return info;
 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
 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 && st->ss->swapuuid) {
 282         printf("            UUID : %08x.%08x.%08x.%08x\n",
 283                                         swapl(*(__u32 *)(sb->uuid+0)),
 284                                         swapl(*(__u32 *)(sb->uuid+4)),
 285                                         swapl(*(__u32 *)(sb->uuid+8)),
 286                                         swapl(*(__u32 *)(sb->uuid+12)));
 287         } else {
 288         printf("            UUID : %08x.%08x.%08x.%08x\n",
 289                                         *(__u32 *)(sb->uuid+0),
 290                                         *(__u32 *)(sb->uuid+4),
 291                                         *(__u32 *)(sb->uuid+8),
 292                                         *(__u32 *)(sb->uuid+12));
 293         }
 294         printf("          Events : %llu\n", (unsigned long long)sb->events);
 295         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 296         printf("           State : %s\n", bitmap_state(sb->state));
 297         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 298         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 299         if (sb->write_behind)
 300                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 301         else
 302                 sprintf(buf, "Normal");
 303         printf("      Write Mode : %s\n", buf);
 304         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 305                                         human_size(sb->sync_size * 512));
 306         if (brief)
 307                 goto free_info;
 308         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 309                         info->total_bits, info->dirty_bits,
 310                         100.0 * info->dirty_bits / (info->total_bits + 1));
 311 free_info:
 312         free(info);
 313         return rv;
 314 }
 315
 316 int CreateBitmap(char *filename, int force, char uuid[16],
 317                  unsigned long chunksize, unsigned long daemon_sleep,
 318                  unsigned long write_behind,
 319                  unsigned long long array_size /* sectors */,
 320                  int major)
 321 {
 322         /*
 323          * Create a bitmap file with a superblock and (optionally) a full bitmap
 324          */
 325
 326         FILE *fp;
 327         int rv = 1;
 328         char block[512];
 329         bitmap_super_t sb;
 330         long long bytes, filesize;
 331
 332         if (!force && access(filename, F_OK) == 0) {
 333                 fprintf(stderr, Name ": bitmap file %s already exists, use --force to overwrite\n", filename);
 334                 return rv;
 335         }
 336
 337         fp = fopen(filename, "w");
 338         if (fp == NULL) {
 339                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 340                         filename, strerror(errno));
 341                 return rv;
 342         }
 343
 344         if (chunksize == UnSet) {
 345                 /* We don't want more than 2^21 chunks, as 2^11 fill up one
 346                  * 4K page (2 bytes per chunk), and 2^10 address of those
 347                  * fill up a 4K indexing page.  2^20 might be safer...
 348                  */
 349                 chunksize = DEFAULT_BITMAP_CHUNK;
 350                 /* <<21 for 2^21 chunks, >>9 to convert bytes to sectors */
 351                 while (array_size > (chunksize << (21-9)))
 352                         chunksize <<= 1;
 353         }
 354
 355         memset(&sb, 0, sizeof(sb));
 356         sb.magic = BITMAP_MAGIC;
 357         sb.version = major;
 358         if (uuid != NULL)
 359                 memcpy(sb.uuid, uuid, 16);
 360         sb.chunksize = chunksize;
 361         sb.daemon_sleep = daemon_sleep;
 362         sb.write_behind = write_behind;
 363         sb.sync_size = array_size;
 364
 365         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 366
 367         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 368                 fprintf(stderr, Name ": failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 369                 goto out;
 370         }
 371
 372         /* calculate the size of the bitmap and write it to disk */
 373         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 374         if (!bytes) {
 375                 rv = 0;
 376                 goto out;
 377         }
 378
 379         filesize = bytes + sizeof(sb);
 380
 381         memset(block, 0xff, sizeof(block));
 382
 383         while (bytes > 0) {
 384                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 385                         fprintf(stderr, Name ": failed to write bitmap file %s: %s\n", filename, strerror(errno));
 386                         goto out;
 387                 }
 388                 bytes -= sizeof(block);
 389         }
 390
 391         rv = 0;
 392         /* make the file be the right size (well, to the nearest byte) */
 393         if (ftruncate(fileno(fp), filesize))
 394                 perror("ftrunace");
 395 out:
 396         fclose(fp);
 397         if (rv)
 398                 unlink(filename); /* possibly corrupted, better get rid of it */
 399         return rv;
 400 }