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_blocks(ext2_filsys fs, blk_t blk, int num,
 149                              blk_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_blk(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 /*
 196  * Helper function for creating the journal using direct I/O routines
 197  */
 198 struct mkjournal_struct {
 199         int             num_blocks;
 200         int             newblocks;
 201         blk_t           blk_to_zero;
 202         int             zero_count;
 203         char            *buf;
 204         errcode_t       err;
 205 };
 206
 207 static int mkjournal_proc(ext2_filsys   fs,
 208                            blk_t        *blocknr,
 209                            e2_blkcnt_t  blockcnt,
 210                            blk_t        ref_block EXT2FS_ATTR((unused)),
 211                            int          ref_offset EXT2FS_ATTR((unused)),
 212                            void         *priv_data)
 213 {
 214         struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
 215         blk_t   new_blk;
 216         static blk_t    last_blk = 0;
 217         errcode_t       retval;
 218
 219         if (*blocknr) {
 220                 last_blk = *blocknr;
 221                 return 0;
 222         }
 223         retval = ext2fs_new_block(fs, last_blk, 0, &new_blk);
 224         if (retval) {
 225                 es->err = retval;
 226                 return BLOCK_ABORT;
 227         }
 228         if (blockcnt > 0)
 229                 es->num_blocks--;
 230
 231         es->newblocks++;
 232         retval = 0;
 233         if (blockcnt <= 0)
 234                 retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);
 235         else {
 236                 if (es->zero_count) {
 237                         if ((es->blk_to_zero + es->zero_count == new_blk) &&
 238                             (es->zero_count < 1024))
 239                                 es->zero_count++;
 240                         else {
 241                                 retval = ext2fs_zero_blocks(fs,
 242                                                             es->blk_to_zero,
 243                                                             es->zero_count,
 244                                                             0, 0);
 245                                 es->zero_count = 0;
 246                         }
 247                 }
 248                 if (es->zero_count == 0) {
 249                         es->blk_to_zero = new_blk;
 250                         es->zero_count = 1;
 251                 }
 252         }
 253
 254         if (blockcnt == 0)
 255                 memset(es->buf, 0, fs->blocksize);
 256
 257         if (retval) {
 258                 es->err = retval;
 259                 return BLOCK_ABORT;
 260         }
 261         *blocknr = new_blk;
 262         last_blk = new_blk;
 263         ext2fs_block_alloc_stats(fs, new_blk, +1);
 264
 265         if (es->num_blocks == 0)
 266                 return (BLOCK_CHANGED | BLOCK_ABORT);
 267         else
 268                 return BLOCK_CHANGED;
 269
 270 }
 271
 272 /*
 273  * This function creates a journal using direct I/O routines.
 274  */
 275 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
 276                                      blk_t size, int flags)
 277 {
 278         char                    *buf;
 279         errcode_t               retval;
 280         struct ext2_inode       inode;
 281         struct mkjournal_struct es;
 282
 283         if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
 284                 return retval;
 285
 286         if ((retval = ext2fs_read_bitmaps(fs)))
 287                 return retval;
 288
 289         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 290                 return retval;
 291
 292         if (inode.i_blocks > 0)
 293                 return EEXIST;
 294
 295         es.num_blocks = size;
 296         es.newblocks = 0;
 297         es.buf = buf;
 298         es.err = 0;
 299         es.zero_count = 0;
 300
 301         retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
 302                                        0, mkjournal_proc, &es);
 303         if (es.err) {
 304                 retval = es.err;
 305                 goto errout;
 306         }
 307         if (es.zero_count) {
 308                 retval = ext2fs_zero_blocks(fs, es.blk_to_zero,
 309                                             es.zero_count, 0, 0);
 310                 if (retval)
 311                         goto errout;
 312         }
 313
 314         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 315                 goto errout;
 316
 317         inode.i_size += fs->blocksize * size;
 318         ext2fs_iblk_add_blocks(fs, &inode, es.newblocks);
 319         inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
 320         inode.i_links_count = 1;
 321         inode.i_mode = LINUX_S_IFREG | 0600;
 322
 323         if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
 324                 goto errout;
 325         retval = 0;
 326
 327         memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
 328         fs->super->s_jnl_blocks[16] = inode.i_size;
 329         fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
 330         ext2fs_mark_super_dirty(fs);
 331
 332 errout:
 333         ext2fs_free_mem(&buf);
 334         return retval;
 335 }
 336
 337 /*
 338  * Find a reasonable journal file size (in blocks) given the number of blocks
 339  * in the filesystem.  For very small filesystems, it is not reasonable to
 340  * have a journal that fills more than half of the filesystem.
 341  */
 342 int ext2fs_default_journal_size(__u64 blocks)
 343 {
 344         if (blocks < 2048)
 345                 return -1;
 346         if (blocks < 32768)
 347                 return (1024);
 348         if (blocks < 256*1024)
 349                 return (4096);
 350         if (blocks < 512*1024)
 351                 return (8192);
 352         if (blocks < 1024*1024)
 353                 return (16384);
 354         return 32768;
 355 }
 356
 357 /*
 358  * This function adds a journal device to a filesystem
 359  */
 360 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
 361 {
 362         struct stat     st;
 363         errcode_t       retval;
 364         char            buf[1024];
 365         journal_superblock_t    *jsb;
 366         int             start;
 367         __u32           i, nr_users;
 368
 369         /* Make sure the device exists and is a block device */
 370         if (stat(journal_dev->device_name, &st) < 0)
 371                 return errno;
 372
 373         if (!S_ISBLK(st.st_mode))
 374                 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
 375
 376         /* Get the journal superblock */
 377         start = 1;
 378         if (journal_dev->blocksize == 1024)
 379                 start++;
 380         if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
 381                 return retval;
 382
 383         jsb = (journal_superblock_t *) buf;
 384         if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
 385             (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
 386                 return EXT2_ET_NO_JOURNAL_SB;
 387
 388         if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
 389                 return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 390
 391         /* Check and see if this filesystem has already been added */
 392         nr_users = ntohl(jsb->s_nr_users);
 393         for (i=0; i < nr_users; i++) {
 394                 if (memcmp(fs->super->s_uuid,
 395                            &jsb->s_users[i*16], 16) == 0)
 396                         break;
 397         }
 398         if (i >= nr_users) {
 399                 memcpy(&jsb->s_users[nr_users*16],
 400                        fs->super->s_uuid, 16);
 401                 jsb->s_nr_users = htonl(nr_users+1);
 402         }
 403
 404         /* Writeback the journal superblock */
 405         if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
 406                 return retval;
 407
 408         fs->super->s_journal_inum = 0;
 409         fs->super->s_journal_dev = st.st_rdev;
 410         memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
 411                sizeof(fs->super->s_journal_uuid));
 412         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 413         ext2fs_mark_super_dirty(fs);
 414         return 0;
 415 }
 416
 417 /*
 418  * This function adds a journal inode to a filesystem, using either
 419  * POSIX routines if the filesystem is mounted, or using direct I/O
 420  * functions if it is not.
 421  */
 422 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
 423 {
 424         errcode_t               retval;
 425         ext2_ino_t              journal_ino;
 426         struct stat             st;
 427         char                    jfile[1024];
 428         int                     mount_flags, f;
 429         int                     fd = -1;
 430
 431         if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
 432                                                jfile, sizeof(jfile)-10)))
 433                 return retval;
 434
 435         if (mount_flags & EXT2_MF_MOUNTED) {
 436                 strcat(jfile, "/.journal");
 437
 438                 /*
 439                  * If .../.journal already exists, make sure any
 440                  * immutable or append-only flags are cleared.
 441                  */
 442 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 443                 (void) chflags (jfile, 0);
 444 #else
 445 #if HAVE_EXT2_IOCTLS
 446                 fd = open(jfile, O_RDONLY);
 447                 if (fd >= 0) {
 448                         f = 0;
 449                         ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 450                         close(fd);
 451                 }
 452 #endif
 453 #endif
 454
 455                 /* Create the journal file */
 456                 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
 457                         return errno;
 458
 459                 if ((retval = write_journal_file(fs, jfile, size, flags)))
 460                         goto errout;
 461
 462                 /* Get inode number of the journal file */
 463                 if (fstat(fd, &st) < 0)
 464                         goto errout;
 465
 466 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 467                 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
 468 #else
 469 #if HAVE_EXT2_IOCTLS
 470                 f = EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
 471                 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 472 #endif
 473 #endif
 474                 if (retval)
 475                         goto errout;
 476
 477                 close(fd);
 478                 journal_ino = st.st_ino;
 479         } else {
 480                 if ((mount_flags & EXT2_MF_BUSY) &&
 481                     !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
 482                         retval = EBUSY;
 483                         goto errout;
 484                 }
 485                 journal_ino = EXT2_JOURNAL_INO;
 486                 if ((retval = write_journal_inode(fs, journal_ino,
 487                                                   size, flags)))
 488                         return retval;
 489         }
 490
 491         fs->super->s_journal_inum = journal_ino;
 492         fs->super->s_journal_dev = 0;
 493         memset(fs->super->s_journal_uuid, 0,
 494                sizeof(fs->super->s_journal_uuid));
 495         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 496
 497         ext2fs_mark_super_dirty(fs);
 498         return 0;
 499 errout:
 500         if (fd > 0)
 501                 close(fd);
 502         return retval;
 503 }
 504
 505 #ifdef DEBUG
 506 main(int argc, char **argv)
 507 {
 508         errcode_t       retval;
 509         char            *device_name;
 510         ext2_filsys     fs;
 511
 512         if (argc < 2) {
 513                 fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
 514                 exit(1);
 515         }
 516         device_name = argv[1];
 517
 518         retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
 519                               unix_io_manager, &fs);
 520         if (retval) {
 521                 com_err(argv[0], retval, "while opening %s", device_name);
 522                 exit(1);
 523         }
 524
 525         retval = ext2fs_add_journal_inode(fs, 1024);
 526         if (retval) {
 527                 com_err(argv[0], retval, "while adding journal to %s",
 528                         device_name);
 529                 exit(1);
 530         }
 531         retval = ext2fs_flush(fs);
 532         if (retval) {
 533                 printf("Warning, had trouble writing out superblocks.\n");
 534         }
 535         ext2fs_close(fs);
 536         exit(0);
 537
 538 }
 539 #endif