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 <sys/types.h>
  22 #include <sys/stat.h>
  23 #include "mdadm.h"
  24 #include <asm/byteorder.h>
  25
  26 #define min(a,b) (((a) < (b)) ? (a) : (b))
  27
  28 inline void sb_le_to_cpu(bitmap_super_t *sb)
  29 {
  30         sb->magic = __le32_to_cpu(sb->magic);
  31         sb->version = __le32_to_cpu(sb->version);
  32         /* uuid gets no translation */
  33         sb->events = __le64_to_cpu(sb->events);
  34         sb->events_cleared = __le64_to_cpu(sb->events_cleared);
  35         sb->state = __le32_to_cpu(sb->state);
  36         sb->chunksize = __le32_to_cpu(sb->chunksize);
  37         sb->daemon_sleep = __le32_to_cpu(sb->daemon_sleep);
  38         sb->sync_size = __le64_to_cpu(sb->sync_size);
  39 }
  40
  41 inline void sb_cpu_to_le(bitmap_super_t *sb)
  42 {
  43         sb_le_to_cpu(sb); /* these are really the same thing */
  44 }
  45
  46 mapping_t bitmap_states[] = {
  47         { "OK", 0 },
  48         { "Out of date", 2 },
  49         { NULL, -1 }
  50 };
  51
  52 const char *bitmap_state(int state_num)
  53 {
  54         char *state = map_num(bitmap_states, state_num);
  55         return state ? state : "Unknown";
  56 }
  57
  58 const char *human_chunksize(unsigned long bytes)
  59 {
  60         static char buf[16];
  61         char *suffixes[] = { "B", "KB", "MB", "GB", "TB", NULL };
  62         int i = 0;
  63
  64         while (bytes >> 10) {
  65                 bytes >>= 10;
  66                 i++;
  67         }
  68
  69         snprintf(buf, sizeof(buf), "%lu %s", bytes, suffixes[i]);
  70
  71         return buf;
  72 }
  73
  74 typedef struct bitmap_info_s {
  75         bitmap_super_t sb;
  76         unsigned long long total_bits;
  77         unsigned long long dirty_bits;
  78 } bitmap_info_t;
  79
  80 /* count the dirty bits in the first num_bits of byte */
  81 inline int count_dirty_bits_byte(char byte, int num_bits)
  82 {
  83         int num = 0;
  84
  85         switch (num_bits) { /* fall through... */
  86                 case 8: if (byte & 128) num++;
  87                 case 7: if (byte &  64) num++;
  88                 case 6: if (byte &  32) num++;
  89                 case 5: if (byte &  16) num++;
  90                 case 4: if (byte &   8) num++;
  91                 case 3: if (byte &   4) num++;
  92                 case 2: if (byte &   2) num++;
  93                 case 1: if (byte &   1) num++;
  94                 default: break;
  95         }
  96
  97         return num;
  98 }
  99
 100 int count_dirty_bits(char *buf, int num_bits)
 101 {
 102         int i, num = 0;
 103
 104         for (i=0; i < num_bits / 8; i++)
 105                 num += count_dirty_bits_byte(buf[i], 8);
 106
 107         if (num_bits % 8) /* not an even byte boundary */
 108                 num += count_dirty_bits_byte(buf[i], num_bits % 8);
 109
 110         return num;
 111 }
 112
 113 /* calculate the size of the bitmap given the array size and bitmap chunksize */
 114 unsigned long long bitmap_bits(unsigned long long array_size,
 115                                 unsigned long chunksize)
 116 {
 117         return (array_size * 512 + chunksize - 1) / chunksize;
 118 }
 119
 120 bitmap_info_t *bitmap_fd_read(int fd, int brief)
 121 {
 122         unsigned long long total_bits = 0, read_bits = 0, dirty_bits = 0;
 123         bitmap_info_t *info;
 124         char buf[512];
 125         int n;
 126
 127         info = malloc(sizeof(*info));
 128         if (info == NULL) {
 129                 fprintf(stderr, Name ": failed to allocate %d bytes\n",
 130                                 sizeof(*info));
 131                 return NULL;
 132         }
 133
 134         if (read(fd, &info->sb, sizeof(info->sb)) != sizeof(info->sb)) {
 135                 fprintf(stderr, Name ": failed to read superblock of bitmap "
 136                         "file: %s\n", strerror(errno));
 137                 free(info);
 138                 return NULL;
 139         }
 140
 141         sb_le_to_cpu(&info->sb); /* convert superblock to CPU byte ordering */
 142
 143         if (brief || info->sb.sync_size == 0)
 144                 goto out;
 145
 146         /* read the rest of the file counting total bits and dirty bits --
 147          * we stop when either:
 148          * 1) we hit EOF, in which case we assume the rest of the bits (if any)
 149          *    are dirty
 150          * 2) we've read the full bitmap, in which case we ignore any trailing
 151          *    data in the file
 152          */
 153         total_bits = bitmap_bits(info->sb.sync_size, info->sb.chunksize);
 154
 155         while ((n = read(fd, buf, sizeof(buf))) > 0) {
 156                 unsigned long long remaining = total_bits - read_bits;
 157
 158                 if (remaining > sizeof(buf) * 8) /* we want the full buffer */
 159                         remaining = sizeof(buf) * 8;
 160                 if (remaining > n * 8) /* the file is truncated */
 161                         remaining = n * 8;
 162                 dirty_bits += count_dirty_bits(buf, remaining);
 163
 164                 read_bits += remaining;
 165                 if (read_bits >= total_bits) /* we've got what we want */
 166                         break;
 167         }
 168
 169         if (read_bits < total_bits) { /* file truncated... */
 170                 fprintf(stderr, Name ": WARNING: bitmap file is not large "
 171                         "enough for array size %llu!\n\n", info->sb.sync_size);
 172                 total_bits = read_bits;
 173         }
 174 out:
 175         info->total_bits = total_bits;
 176         info->dirty_bits = dirty_bits;
 177         return info;
 178 }
 179
 180 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 181 {
 182         int fd;
 183         bitmap_info_t *info;
 184         struct stat stb;
 185         struct supertype *st = *stp;
 186
 187         fd = open(filename, O_RDONLY);
 188         if (fd < 0) {
 189                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 190                                 filename, strerror(errno));
 191                 return NULL;
 192         }
 193         fstat(fd, &stb);
 194         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 195                 /* block device, so we are probably after an internal bitmap */
 196                 if (!st) st = guess_super(fd);
 197                 if (!st) {
 198                         /* just look at device... */
 199                         lseek(fd, 0, 0);
 200                 } else {
 201                         st->ss->locate_bitmap(st, fd, NULL);
 202                 }
 203                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 204                 *stp = st;
 205         }
 206
 207         info = bitmap_fd_read(fd, brief);
 208         close(fd);
 209         return info;
 210 }
 211
 212 __u32 swapl(__u32 l)
 213 {
 214         char *c = (char*)&l;
 215         char t= c[0];
 216         c[0] = c[3];
 217         c[3] = t;
 218
 219         t = c[1];
 220         c[1] = c[2];
 221         c[2] = t;
 222         return l;
 223 }
 224 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 225 {
 226         /*
 227          * Read the bitmap file and display its contents
 228          */
 229
 230         bitmap_super_t *sb;
 231         bitmap_info_t *info;
 232         int rv = 1;
 233         char buf[64];
 234
 235         info = bitmap_file_read(filename, brief, &st);
 236         if (!info)
 237                 return rv;
 238
 239         sb = &info->sb;
 240         printf("        Filename : %s\n", filename);
 241         printf("           Magic : %08x\n", sb->magic);
 242         if (sb->magic != BITMAP_MAGIC) {
 243                 fprintf(stderr, Name ": invalid bitmap magic 0x%x, the bitmap file appears to be corrupted\n", sb->magic);
 244         }
 245         printf("         Version : %d\n", sb->version);
 246         if (sb->version != BITMAP_MAJOR) {
 247                 fprintf(stderr, Name ": unknown bitmap version %d, either the bitmap file is corrupted or you need to upgrade your tools\n", sb->version);
 248                 goto free_info;
 249         }
 250
 251         rv = 0;
 252         if (st && st->ss->swapuuid) {
 253         printf("            UUID : %08x.%08x.%08x.%08x\n",
 254                                         swapl(*(__u32 *)(sb->uuid+0)),
 255                                         swapl(*(__u32 *)(sb->uuid+4)),
 256                                         swapl(*(__u32 *)(sb->uuid+8)),
 257                                         swapl(*(__u32 *)(sb->uuid+12)));
 258         } else {
 259         printf("            UUID : %08x.%08x.%08x.%08x\n",
 260                                         *(__u32 *)(sb->uuid+0),
 261                                         *(__u32 *)(sb->uuid+4),
 262                                         *(__u32 *)(sb->uuid+8),
 263                                         *(__u32 *)(sb->uuid+12));
 264         }
 265         printf("          Events : %llu\n", sb->events);
 266         printf("  Events Cleared : %llu\n", sb->events_cleared);
 267         printf("           State : %s\n", bitmap_state(sb->state));
 268         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 269         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 270         if (sb->write_behind)
 271                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 272         else
 273                 sprintf(buf, "Normal");
 274         printf("      Write Mode : %s\n", buf);
 275         printf("       Sync Size : %llu%s\n", sb->sync_size/2,
 276                                         human_size(sb->sync_size * 512));
 277         if (brief)
 278                 goto free_info;
 279         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 280                         info->total_bits, info->dirty_bits,
 281                         100.0 * info->dirty_bits / (info->total_bits + 1));
 282 free_info:
 283         free(info);
 284         return rv;
 285 }
 286
 287 int CreateBitmap(char *filename, int force, char uuid[16],
 288                  unsigned long chunksize, unsigned long daemon_sleep,
 289                  unsigned long write_behind,
 290                  unsigned long long array_size /* sectors */)
 291 {
 292         /*
 293          * Create a bitmap file with a superblock and (optionally) a full bitmap
 294          */
 295
 296         FILE *fp;
 297         int rv = 1;
 298         char block[512];
 299         bitmap_super_t sb;
 300         long long bytes, filesize;
 301
 302         if (!force && access(filename, F_OK) == 0) {
 303                 fprintf(stderr, Name ": bitmap file %s already exists, use --force to overwrite\n", filename);
 304                 return rv;
 305         }
 306
 307         fp = fopen(filename, "w");
 308         if (fp == NULL) {
 309                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 310                         filename, strerror(errno));
 311                 return rv;
 312         }
 313
 314         memset(&sb, 0, sizeof(sb));
 315         sb.magic = BITMAP_MAGIC;
 316         sb.version = BITMAP_MAJOR;
 317         if (uuid != NULL)
 318                 memcpy(sb.uuid, uuid, 16);
 319         sb.chunksize = chunksize;
 320         sb.daemon_sleep = daemon_sleep;
 321         sb.write_behind = write_behind;
 322         sb.sync_size = array_size;
 323
 324         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 325
 326         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 327                 fprintf(stderr, Name ": failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 328                 goto out;
 329         }
 330
 331         /* calculate the size of the bitmap and write it to disk */
 332         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 333         if (!bytes) {
 334                 rv = 0;
 335                 goto out;
 336         }
 337
 338         filesize = bytes + sizeof(sb);
 339
 340         memset(block, 0xff, sizeof(block));
 341
 342         while (bytes > 0) {
 343                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 344                         fprintf(stderr, Name ": failed to write bitmap file %s: %s\n", filename, strerror(errno));
 345                         goto out;
 346                 }
 347                 bytes -= sizeof(block);
 348         }
 349
 350         rv = 0;
 351         /* make the file be the right size (well, to the nearest byte) */
 352         ftruncate(fileno(fp), filesize);
 353 out:
 354         fclose(fp);
 355         if (rv)
 356                 unlink(filename); /* possibly corrupted, better get rid of it */
 357         return rv;
 358 }