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  48         { "Out of date", 2 },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 %zd 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",
 172                         (unsigned long long)info->sb.sync_size);
 173                 total_bits = read_bits;
 174         }
 175 out:
 176         info->total_bits = total_bits;
 177         info->dirty_bits = dirty_bits;
 178         return info;
 179 }
 180
 181 bitmap_info_t *bitmap_file_read(char *filename, int brief, struct supertype **stp)
 182 {
 183         int fd;
 184         bitmap_info_t *info;
 185         struct stat stb;
 186         struct supertype *st = *stp;
 187
 188         fd = open(filename, O_RDONLY);
 189         if (fd < 0) {
 190                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 191                                 filename, strerror(errno));
 192                 return NULL;
 193         }
 194         fstat(fd, &stb);
 195         if ((S_IFMT & stb.st_mode) == S_IFBLK) {
 196                 /* block device, so we are probably after an internal bitmap */
 197                 if (!st) st = guess_super(fd);
 198                 if (!st) {
 199                         /* just look at device... */
 200                         lseek(fd, 0, 0);
 201                 } else {
 202                         st->ss->locate_bitmap(st, fd, NULL);
 203                 }
 204                 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
 205                 *stp = st;
 206         }
 207
 208         info = bitmap_fd_read(fd, brief);
 209         close(fd);
 210         return info;
 211 }
 212
 213 __u32 swapl(__u32 l)
 214 {
 215         char *c = (char*)&l;
 216         char t= c[0];
 217         c[0] = c[3];
 218         c[3] = t;
 219
 220         t = c[1];
 221         c[1] = c[2];
 222         c[2] = t;
 223         return l;
 224 }
 225 int ExamineBitmap(char *filename, int brief, struct supertype *st)
 226 {
 227         /*
 228          * Read the bitmap file and display its contents
 229          */
 230
 231         bitmap_super_t *sb;
 232         bitmap_info_t *info;
 233         int rv = 1;
 234         char buf[64];
 235
 236         info = bitmap_file_read(filename, brief, &st);
 237         if (!info)
 238                 return rv;
 239
 240         sb = &info->sb;
 241         printf("        Filename : %s\n", filename);
 242         printf("           Magic : %08x\n", sb->magic);
 243         if (sb->magic != BITMAP_MAGIC) {
 244                 fprintf(stderr, Name ": invalid bitmap magic 0x%x, the bitmap file appears to be corrupted\n", sb->magic);
 245         }
 246         printf("         Version : %d\n", sb->version);
 247         if (sb->version < BITMAP_MAJOR_LO ||
 248             sb->version > BITMAP_MAJOR_HI) {
 249                 fprintf(stderr, Name ": unknown bitmap version %d, either the bitmap file is corrupted or you need to upgrade your tools\n", sb->version);
 250                 goto free_info;
 251         }
 252
 253         rv = 0;
 254         if (st && st->ss->swapuuid) {
 255         printf("            UUID : %08x.%08x.%08x.%08x\n",
 256                                         swapl(*(__u32 *)(sb->uuid+0)),
 257                                         swapl(*(__u32 *)(sb->uuid+4)),
 258                                         swapl(*(__u32 *)(sb->uuid+8)),
 259                                         swapl(*(__u32 *)(sb->uuid+12)));
 260         } else {
 261         printf("            UUID : %08x.%08x.%08x.%08x\n",
 262                                         *(__u32 *)(sb->uuid+0),
 263                                         *(__u32 *)(sb->uuid+4),
 264                                         *(__u32 *)(sb->uuid+8),
 265                                         *(__u32 *)(sb->uuid+12));
 266         }
 267         printf("          Events : %llu\n", (unsigned long long)sb->events);
 268         printf("  Events Cleared : %llu\n", (unsigned long long)sb->events_cleared);
 269         printf("           State : %s\n", bitmap_state(sb->state));
 270         printf("       Chunksize : %s\n", human_chunksize(sb->chunksize));
 271         printf("          Daemon : %ds flush period\n", sb->daemon_sleep);
 272         if (sb->write_behind)
 273                 sprintf(buf, "Allow write behind, max %d", sb->write_behind);
 274         else
 275                 sprintf(buf, "Normal");
 276         printf("      Write Mode : %s\n", buf);
 277         printf("       Sync Size : %llu%s\n", (unsigned long long)sb->sync_size/2,
 278                                         human_size(sb->sync_size * 512));
 279         if (brief)
 280                 goto free_info;
 281         printf("          Bitmap : %llu bits (chunks), %llu dirty (%2.1f%%)\n",
 282                         info->total_bits, info->dirty_bits,
 283                         100.0 * info->dirty_bits / (info->total_bits + 1));
 284 free_info:
 285         free(info);
 286         return rv;
 287 }
 288
 289 int CreateBitmap(char *filename, int force, char uuid[16],
 290                  unsigned long chunksize, unsigned long daemon_sleep,
 291                  unsigned long write_behind,
 292                  unsigned long long array_size /* sectors */,
 293                  int major)
 294 {
 295         /*
 296          * Create a bitmap file with a superblock and (optionally) a full bitmap
 297          */
 298
 299         FILE *fp;
 300         int rv = 1;
 301         char block[512];
 302         bitmap_super_t sb;
 303         long long bytes, filesize;
 304
 305         if (!force && access(filename, F_OK) == 0) {
 306                 fprintf(stderr, Name ": bitmap file %s already exists, use --force to overwrite\n", filename);
 307                 return rv;
 308         }
 309
 310         fp = fopen(filename, "w");
 311         if (fp == NULL) {
 312                 fprintf(stderr, Name ": failed to open bitmap file %s: %s\n",
 313                         filename, strerror(errno));
 314                 return rv;
 315         }
 316
 317         memset(&sb, 0, sizeof(sb));
 318         sb.magic = BITMAP_MAGIC;
 319         sb.version = major;
 320         if (uuid != NULL)
 321                 memcpy(sb.uuid, uuid, 16);
 322         sb.chunksize = chunksize;
 323         sb.daemon_sleep = daemon_sleep;
 324         sb.write_behind = write_behind;
 325         sb.sync_size = array_size;
 326
 327         sb_cpu_to_le(&sb); /* convert to on-disk byte ordering */
 328
 329         if (fwrite(&sb, sizeof(sb), 1, fp) != 1) {
 330                 fprintf(stderr, Name ": failed to write superblock to bitmap file %s: %s\n", filename, strerror(errno));
 331                 goto out;
 332         }
 333
 334         /* calculate the size of the bitmap and write it to disk */
 335         bytes = (bitmap_bits(array_size, chunksize) + 7) / 8;
 336         if (!bytes) {
 337                 rv = 0;
 338                 goto out;
 339         }
 340
 341         filesize = bytes + sizeof(sb);
 342
 343         memset(block, 0xff, sizeof(block));
 344
 345         while (bytes > 0) {
 346                 if (fwrite(block, sizeof(block), 1, fp) != 1) {
 347                         fprintf(stderr, Name ": failed to write bitmap file %s: %s\n", filename, strerror(errno));
 348                         goto out;
 349                 }
 350                 bytes -= sizeof(block);
 351         }
 352
 353         rv = 0;
 354         /* make the file be the right size (well, to the nearest byte) */
 355         ftruncate(fileno(fp), filesize);
 356 out:
 357         fclose(fp);
 358         if (rv)
 359                 unlink(filename); /* possibly corrupted, better get rid of it */
 360         return rv;
 361 }