lib/ext2fs/mkjournal.c

   1 /*
   2  * mkjournal.c --- make a journal for a filesystem
   3  *
   4  * Copyright (C) 2000 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #include <stdio.h>
  13 #include <string.h>
  14 #if HAVE_UNISTD_H
  15 #include <unistd.h>
  16 #endif
  17 #if HAVE_ERRNO_H
  18 #include <errno.h>
  19 #endif
  20 #include <fcntl.h>
  21 #include <time.h>
  22 #if HAVE_SYS_STAT_H
  23 #include <sys/stat.h>
  24 #endif
  25 #if HAVE_SYS_TYPES_H
  26 #include <sys/types.h>
  27 #endif
  28 #if HAVE_SYS_IOCTL_H
  29 #include <sys/ioctl.h>
  30 #endif
  31 #if HAVE_NETINET_IN_H
  32 #include <netinet/in.h>
  33 #endif
  34
  35 #include "ext2_fs.h"
  36 #include "e2p/e2p.h"
  37 #include "ext2fs.h"
  38 #include "jfs_user.h"
  39
  40 /*
  41  * This function automatically sets up the journal superblock and
  42  * returns it as an allocated block.
  43  */
  44 errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
  45                                            __u32 size, int flags,
  46                                            char  **ret_jsb)
  47 {
  48         errcode_t               retval;
  49         journal_superblock_t    *jsb;
  50
  51         if (size < 1024)
  52                 return EXT2_ET_JOURNAL_TOO_SMALL;
  53
  54         if ((retval = ext2fs_get_mem(fs->blocksize, &jsb)))
  55                 return retval;
  56
  57         memset (jsb, 0, fs->blocksize);
  58
  59         jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
  60         if (flags & EXT2_MKJOURNAL_V1_SUPER)
  61                 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
  62         else
  63                 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
  64         jsb->s_blocksize = htonl(fs->blocksize);
  65         jsb->s_maxlen = htonl(size);
  66         jsb->s_nr_users = htonl(1);
  67         jsb->s_first = htonl(1);
  68         jsb->s_sequence = htonl(1);
  69         memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
  70         /*
  71          * If we're creating an external journal device, we need to
  72          * adjust these fields.
  73          */
  74         if (fs->super->s_feature_incompat &
  75             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
  76                 jsb->s_nr_users = 0;
  77                 if (fs->blocksize == 1024)
  78                         jsb->s_first = htonl(3);
  79                 else
  80                         jsb->s_first = htonl(2);
  81         }
  82
  83         *ret_jsb = (char *) jsb;
  84         return 0;
  85 }
  86
  87 /*
  88  * This function writes a journal using POSIX routines.  It is used
  89  * for creating external journals and creating journals on live
  90  * filesystems.
  91  */
  92 static errcode_t write_journal_file(ext2_filsys fs, char *filename,
  93                                     blk_t size, int flags)
  94 {
  95         errcode_t       retval;
  96         char            *buf = 0;
  97         int             fd, ret_size;
  98         blk_t           i;
  99
 100         if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
 101                 return retval;
 102
 103         /* Open the device or journal file */
 104         if ((fd = open(filename, O_WRONLY)) < 0) {
 105                 retval = errno;
 106                 goto errout;
 107         }
 108
 109         /* Write the superblock out */
 110         retval = EXT2_ET_SHORT_WRITE;
 111         ret_size = write(fd, buf, fs->blocksize);
 112         if (ret_size < 0) {
 113                 retval = errno;
 114                 goto errout;
 115         }
 116         if (ret_size != (int) fs->blocksize)
 117                 goto errout;
 118         memset(buf, 0, fs->blocksize);
 119
 120         for (i = 1; i < size; i++) {
 121                 ret_size = write(fd, buf, fs->blocksize);
 122                 if (ret_size < 0) {
 123                         retval = errno;
 124                         goto errout;
 125                 }
 126                 if (ret_size != (int) fs->blocksize)
 127                         goto errout;
 128         }
 129         close(fd);
 130
 131         retval = 0;
 132 errout:
 133         ext2fs_free_mem(&buf);
 134         return retval;
 135 }
 136
 137 /*
 138  * Convenience function which zeros out _num_ blocks starting at
 139  * _blk_.  In case of an error, the details of the error is returned
 140  * via _ret_blk_ and _ret_count_ if they are non-NULL pointers.
 141  * Returns 0 on success, and an error code on an error.
 142  *
 143  * As a special case, if the first argument is NULL, then it will
 144  * attempt to free the static zeroizing buffer.  (This is to keep
 145  * programs that check for memory leaks happy.)
 146  */
 147 #define STRIDE_LENGTH 8
 148 errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num,
 149                               blk64_t *ret_blk, int *ret_count)
 150 {
 151         int             j, count;
 152         static char     *buf;
 153         errcode_t       retval;
 154
 155         /* If fs is null, clean up the static buffer and return */
 156         if (!fs) {
 157                 if (buf) {
 158                         free(buf);
 159                         buf = 0;
 160                 }
 161                 return 0;
 162         }
 163         /* Allocate the zeroizing buffer if necessary */
 164         if (!buf) {
 165                 buf = malloc(fs->blocksize * STRIDE_LENGTH);
 166                 if (!buf)
 167                         return ENOMEM;
 168                 memset(buf, 0, fs->blocksize * STRIDE_LENGTH);
 169         }
 170         /* OK, do the write loop */
 171         j=0;
 172         while (j < num) {
 173                 if (blk % STRIDE_LENGTH) {
 174                         count = STRIDE_LENGTH - (blk % STRIDE_LENGTH);
 175                         if (count > (num - j))
 176                                 count = num - j;
 177                 } else {
 178                         count = num - j;
 179                         if (count > STRIDE_LENGTH)
 180                                 count = STRIDE_LENGTH;
 181                 }
 182                 retval = io_channel_write_blk64(fs->io, blk, count, buf);
 183                 if (retval) {
 184                         if (ret_count)
 185                                 *ret_count = count;
 186                         if (ret_blk)
 187                                 *ret_blk = blk;
 188                         return retval;
 189                 }
 190                 j += count; blk += count;
 191         }
 192         return 0;
 193 }
 194
 195 errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num,
 196                              blk_t *ret_blk, int *ret_count)
 197 {
 198         blk64_t ret_blk2;
 199         errcode_t retval;
 200
 201         retval = ext2fs_zero_blocks2(fs, blk, num, &ret_blk2, ret_count);
 202         if (retval)
 203                 *ret_blk = (blk_t) ret_blk2;
 204         return retval;
 205 }
 206
 207 /*
 208  * Helper function for creating the journal using direct I/O routines
 209  */
 210 struct mkjournal_struct {
 211         int             num_blocks;
 212         int             newblocks;
 213         blk_t           goal;
 214         blk_t           blk_to_zero;
 215         int             zero_count;
 216         char            *buf;
 217         errcode_t       err;
 218 };
 219
 220 static int mkjournal_proc(ext2_filsys   fs,
 221                            blk_t        *blocknr,
 222                            e2_blkcnt_t  blockcnt,
 223                            blk_t        ref_block EXT2FS_ATTR((unused)),
 224                            int          ref_offset EXT2FS_ATTR((unused)),
 225                            void         *priv_data)
 226 {
 227         struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
 228         blk_t   new_blk;
 229         errcode_t       retval;
 230
 231         if (*blocknr) {
 232                 es->goal = *blocknr;
 233                 return 0;
 234         }
 235         retval = ext2fs_new_block(fs, es->goal, 0, &new_blk);
 236         if (retval) {
 237                 es->err = retval;
 238                 return BLOCK_ABORT;
 239         }
 240         if (blockcnt >= 0)
 241                 es->num_blocks--;
 242
 243         es->newblocks++;
 244         retval = 0;
 245         if (blockcnt <= 0)
 246                 retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);
 247         else {
 248                 if (es->zero_count) {
 249                         if ((es->blk_to_zero + es->zero_count == new_blk) &&
 250                             (es->zero_count < 1024))
 251                                 es->zero_count++;
 252                         else {
 253                                 retval = ext2fs_zero_blocks(fs,
 254                                                             es->blk_to_zero,
 255                                                             es->zero_count,
 256                                                             0, 0);
 257                                 es->zero_count = 0;
 258                         }
 259                 }
 260                 if (es->zero_count == 0) {
 261                         es->blk_to_zero = new_blk;
 262                         es->zero_count = 1;
 263                 }
 264         }
 265
 266         if (blockcnt == 0)
 267                 memset(es->buf, 0, fs->blocksize);
 268
 269         if (retval) {
 270                 es->err = retval;
 271                 return BLOCK_ABORT;
 272         }
 273         *blocknr = es->goal = new_blk;
 274         ext2fs_block_alloc_stats(fs, new_blk, +1);
 275
 276         if (es->num_blocks == 0)
 277                 return (BLOCK_CHANGED | BLOCK_ABORT);
 278         else
 279                 return BLOCK_CHANGED;
 280
 281 }
 282
 283 /*
 284  * This function creates a journal using direct I/O routines.
 285  */
 286 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
 287                                      blk_t size, int flags)
 288 {
 289         char                    *buf;
 290         dgrp_t                  group, start, end, i, log_flex;
 291         errcode_t               retval;
 292         struct ext2_inode       inode;
 293         struct mkjournal_struct es;
 294
 295         if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
 296                 return retval;
 297
 298         if ((retval = ext2fs_read_bitmaps(fs)))
 299                 return retval;
 300
 301         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 302                 return retval;
 303
 304         if (inode.i_blocks > 0)
 305                 return EEXIST;
 306
 307         es.num_blocks = size;
 308         es.newblocks = 0;
 309         es.buf = buf;
 310         es.err = 0;
 311         es.zero_count = 0;
 312
 313         if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) {
 314                 inode.i_flags |= EXT4_EXTENTS_FL;
 315                 if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
 316                         return retval;
 317         }
 318
 319         /*
 320          * Set the initial goal block to be roughly at the middle of
 321          * the filesystem.  Pick a group that has the largest number
 322          * of free blocks.
 323          */
 324         group = ext2fs_group_of_blk(fs, (fs->super->s_blocks_count -
 325                                          fs->super->s_first_data_block) / 2);
 326         log_flex = 1 << fs->super->s_log_groups_per_flex;
 327         if (fs->super->s_log_groups_per_flex && (group > log_flex)) {
 328                 group = group & ~(log_flex - 1);
 329                 while ((group < fs->group_desc_count) &&
 330                        fs->group_desc[group].bg_free_blocks_count == 0)
 331                         group++;
 332                 if (group == fs->group_desc_count)
 333                         group = 0;
 334                 start = group;
 335         } else
 336                 start = (group > 0) ? group-1 : group;
 337         end = ((group+1) < fs->group_desc_count) ? group+1 : group;
 338         group = start;
 339         for (i=start+1; i <= end; i++)
 340                 if (fs->group_desc[i].bg_free_blocks_count >
 341                     fs->group_desc[group].bg_free_blocks_count)
 342                         group = i;
 343
 344         es.goal = (fs->super->s_blocks_per_group * group) +
 345                 fs->super->s_first_data_block;
 346
 347         retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
 348                                        0, mkjournal_proc, &es);
 349         if (es.err) {
 350                 retval = es.err;
 351                 goto errout;
 352         }
 353         if (es.zero_count) {
 354                 retval = ext2fs_zero_blocks(fs, es.blk_to_zero,
 355                                             es.zero_count, 0, 0);
 356                 if (retval)
 357                         goto errout;
 358         }
 359
 360         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 361                 goto errout;
 362
 363         inode.i_size += fs->blocksize * size;
 364         ext2fs_iblk_add_blocks(fs, &inode, es.newblocks);
 365         inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
 366         inode.i_links_count = 1;
 367         inode.i_mode = LINUX_S_IFREG | 0600;
 368
 369         if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode)))
 370                 goto errout;
 371         retval = 0;
 372
 373         memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
 374         fs->super->s_jnl_blocks[16] = inode.i_size;
 375         fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
 376         ext2fs_mark_super_dirty(fs);
 377
 378 errout:
 379         ext2fs_free_mem(&buf);
 380         return retval;
 381 }
 382
 383 /*
 384  * Find a reasonable journal file size (in blocks) given the number of blocks
 385  * in the filesystem.  For very small filesystems, it is not reasonable to
 386  * have a journal that fills more than half of the filesystem.
 387  */
 388 int ext2fs_default_journal_size(__u64 blocks)
 389 {
 390         if (blocks < 2048)
 391                 return -1;
 392         if (blocks < 32768)
 393                 return (1024);
 394         if (blocks < 256*1024)
 395                 return (4096);
 396         if (blocks < 512*1024)
 397                 return (8192);
 398         if (blocks < 1024*1024)
 399                 return (16384);
 400         return 32768;
 401 }
 402
 403 /*
 404  * This function adds a journal device to a filesystem
 405  */
 406 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
 407 {
 408         struct stat     st;
 409         errcode_t       retval;
 410         char            buf[1024];
 411         journal_superblock_t    *jsb;
 412         int             start;
 413         __u32           i, nr_users;
 414
 415         /* Make sure the device exists and is a block device */
 416         if (stat(journal_dev->device_name, &st) < 0)
 417                 return errno;
 418
 419         if (!S_ISBLK(st.st_mode))
 420                 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
 421
 422         /* Get the journal superblock */
 423         start = 1;
 424         if (journal_dev->blocksize == 1024)
 425                 start++;
 426         if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
 427                 return retval;
 428
 429         jsb = (journal_superblock_t *) buf;
 430         if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
 431             (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
 432                 return EXT2_ET_NO_JOURNAL_SB;
 433
 434         if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
 435                 return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 436
 437         /* Check and see if this filesystem has already been added */
 438         nr_users = ntohl(jsb->s_nr_users);
 439         for (i=0; i < nr_users; i++) {
 440                 if (memcmp(fs->super->s_uuid,
 441                            &jsb->s_users[i*16], 16) == 0)
 442                         break;
 443         }
 444         if (i >= nr_users) {
 445                 memcpy(&jsb->s_users[nr_users*16],
 446                        fs->super->s_uuid, 16);
 447                 jsb->s_nr_users = htonl(nr_users+1);
 448         }
 449
 450         /* Writeback the journal superblock */
 451         if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
 452                 return retval;
 453
 454         fs->super->s_journal_inum = 0;
 455         fs->super->s_journal_dev = st.st_rdev;
 456         memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
 457                sizeof(fs->super->s_journal_uuid));
 458         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 459         ext2fs_mark_super_dirty(fs);
 460         return 0;
 461 }
 462
 463 /*
 464  * This function adds a journal inode to a filesystem, using either
 465  * POSIX routines if the filesystem is mounted, or using direct I/O
 466  * functions if it is not.
 467  */
 468 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
 469 {
 470         errcode_t               retval;
 471         ext2_ino_t              journal_ino;
 472         struct stat             st;
 473         char                    jfile[1024];
 474         int                     mount_flags, f;
 475         int                     fd = -1;
 476
 477         if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
 478                                                jfile, sizeof(jfile)-10)))
 479                 return retval;
 480
 481         if (mount_flags & EXT2_MF_MOUNTED) {
 482                 strcat(jfile, "/.journal");
 483
 484                 /*
 485                  * If .../.journal already exists, make sure any
 486                  * immutable or append-only flags are cleared.
 487                  */
 488 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 489                 (void) chflags (jfile, 0);
 490 #else
 491 #if HAVE_EXT2_IOCTLS
 492                 fd = open(jfile, O_RDONLY);
 493                 if (fd >= 0) {
 494                         f = 0;
 495                         ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 496                         close(fd);
 497                 }
 498 #endif
 499 #endif
 500
 501                 /* Create the journal file */
 502                 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
 503                         return errno;
 504
 505                 if ((retval = write_journal_file(fs, jfile, size, flags)))
 506                         goto errout;
 507
 508                 /* Get inode number of the journal file */
 509                 if (fstat(fd, &st) < 0)
 510                         goto errout;
 511
 512 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 513                 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
 514 #else
 515 #if HAVE_EXT2_IOCTLS
 516                 f = EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
 517                 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 518 #endif
 519 #endif
 520                 if (retval)
 521                         goto errout;
 522
 523                 close(fd);
 524                 journal_ino = st.st_ino;
 525         } else {
 526                 if ((mount_flags & EXT2_MF_BUSY) &&
 527                     !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
 528                         retval = EBUSY;
 529                         goto errout;
 530                 }
 531                 journal_ino = EXT2_JOURNAL_INO;
 532                 if ((retval = write_journal_inode(fs, journal_ino,
 533                                                   size, flags)))
 534                         return retval;
 535         }
 536
 537         fs->super->s_journal_inum = journal_ino;
 538         fs->super->s_journal_dev = 0;
 539         memset(fs->super->s_journal_uuid, 0,
 540                sizeof(fs->super->s_journal_uuid));
 541         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 542
 543         ext2fs_mark_super_dirty(fs);
 544         return 0;
 545 errout:
 546         if (fd > 0)
 547                 close(fd);
 548         return retval;
 549 }
 550
 551 #ifdef DEBUG
 552 main(int argc, char **argv)
 553 {
 554         errcode_t       retval;
 555         char            *device_name;
 556         ext2_filsys     fs;
 557
 558         if (argc < 2) {
 559                 fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
 560                 exit(1);
 561         }
 562         device_name = argv[1];
 563
 564         retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
 565                               unix_io_manager, &fs);
 566         if (retval) {
 567                 com_err(argv[0], retval, "while opening %s", device_name);
 568                 exit(1);
 569         }
 570
 571         retval = ext2fs_add_journal_inode(fs, 1024);
 572         if (retval) {
 573                 com_err(argv[0], retval, "while adding journal to %s",
 574                         device_name);
 575                 exit(1);
 576         }
 577         retval = ext2fs_flush(fs);
 578         if (retval) {
 579                 printf("Warning, had trouble writing out superblocks.\n");
 580         }
 581         ext2fs_close(fs);
 582         exit(0);
 583
 584 }
 585 #endif