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 Library
   8  * General Public License, version 2.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include <stdio.h>
  14 #include <string.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #if HAVE_ERRNO_H
  19 #include <errno.h>
  20 #endif
  21 #include <fcntl.h>
  22 #include <time.h>
  23 #if HAVE_SYS_STAT_H
  24 #include <sys/stat.h>
  25 #endif
  26 #if HAVE_SYS_TYPES_H
  27 #include <sys/types.h>
  28 #endif
  29 #if HAVE_SYS_IOCTL_H
  30 #include <sys/ioctl.h>
  31 #endif
  32 #if HAVE_NETINET_IN_H
  33 #include <netinet/in.h>
  34 #endif
  35
  36 #include "ext2_fs.h"
  37 #include "e2p/e2p.h"
  38 #include "ext2fs.h"
  39 #include "jfs_user.h"
  40
  41 /*
  42  * This function automatically sets up the journal superblock and
  43  * returns it as an allocated block.
  44  */
  45 errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
  46                                            __u32 num_blocks, int flags,
  47                                            char  **ret_jsb)
  48 {
  49         errcode_t               retval;
  50         journal_superblock_t    *jsb;
  51
  52         if (num_blocks < JFS_MIN_JOURNAL_BLOCKS)
  53                 return EXT2_ET_JOURNAL_TOO_SMALL;
  54
  55         if ((retval = ext2fs_get_mem(fs->blocksize, &jsb)))
  56                 return retval;
  57
  58         memset (jsb, 0, fs->blocksize);
  59
  60         jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
  61         if (flags & EXT2_MKJOURNAL_V1_SUPER)
  62                 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
  63         else
  64                 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
  65         jsb->s_blocksize = htonl(fs->blocksize);
  66         jsb->s_maxlen = htonl(num_blocks);
  67         jsb->s_nr_users = htonl(1);
  68         jsb->s_first = htonl(1);
  69         jsb->s_sequence = htonl(1);
  70         memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
  71         /*
  72          * If we're creating an external journal device, we need to
  73          * adjust these fields.
  74          */
  75         if (fs->super->s_feature_incompat &
  76             EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
  77                 jsb->s_nr_users = 0;
  78                 jsb->s_first = htonl(ext2fs_journal_sb_start(fs->blocksize) + 1);
  79         }
  80
  81         *ret_jsb = (char *) jsb;
  82         return 0;
  83 }
  84
  85 /*
  86  * This function writes a journal using POSIX routines.  It is used
  87  * for creating external journals and creating journals on live
  88  * filesystems.
  89  */
  90 static errcode_t write_journal_file(ext2_filsys fs, char *filename,
  91                                     blk_t num_blocks, int flags)
  92 {
  93         errcode_t       retval;
  94         char            *buf = 0;
  95         int             fd, ret_size;
  96         blk_t           i;
  97
  98         if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags,
  99                                                        &buf)))
 100                 return retval;
 101
 102         /* Open the device or journal file */
 103         if ((fd = open(filename, O_WRONLY)) < 0) {
 104                 retval = errno;
 105                 goto errfree;
 106         }
 107
 108         /* Write the superblock out */
 109         retval = EXT2_ET_SHORT_WRITE;
 110         ret_size = write(fd, buf, fs->blocksize);
 111         if (ret_size < 0) {
 112                 retval = errno;
 113                 goto errout;
 114         }
 115         if (ret_size != (int) fs->blocksize)
 116                 goto errout;
 117         memset(buf, 0, fs->blocksize);
 118
 119         if (flags & EXT2_MKJOURNAL_LAZYINIT)
 120                 goto success;
 121
 122         for (i = 1; i < num_blocks; i++) {
 123                 ret_size = write(fd, buf, fs->blocksize);
 124                 if (ret_size < 0) {
 125                         retval = errno;
 126                         goto errout;
 127                 }
 128                 if (ret_size != (int) fs->blocksize)
 129                         goto errout;
 130         }
 131
 132 success:
 133         retval = 0;
 134 errout:
 135         close(fd);
 136 errfree:
 137         ext2fs_free_mem(&buf);
 138         return retval;
 139 }
 140
 141 /*
 142  * Convenience function which zeros out _num_ blocks starting at
 143  * _blk_.  In case of an error, the details of the error is returned
 144  * via _ret_blk_ and _ret_count_ if they are non-NULL pointers.
 145  * Returns 0 on success, and an error code on an error.
 146  *
 147  * As a special case, if the first argument is NULL, then it will
 148  * attempt to free the static zeroizing buffer.  (This is to keep
 149  * programs that check for memory leaks happy.)
 150  */
 151 #define MAX_STRIDE_LENGTH (4194304 / (int) fs->blocksize)
 152 errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num,
 153                               blk64_t *ret_blk, int *ret_count)
 154 {
 155         int             j, count;
 156         static void     *buf;
 157         static int      stride_length;
 158         errcode_t       retval;
 159
 160         /* If fs is null, clean up the static buffer and return */
 161         if (!fs) {
 162                 if (buf) {
 163                         free(buf);
 164                         buf = 0;
 165                 }
 166                 return 0;
 167         }
 168
 169         /* Deal with zeroing less than 1 block */
 170         if (num <= 0)
 171                 return 0;
 172
 173         /* Try a zero out command, if supported */
 174         retval = io_channel_zeroout(fs->io, blk, num);
 175         if (retval == 0)
 176                 return 0;
 177
 178         /* Allocate the zeroizing buffer if necessary */
 179         if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) {
 180                 void *p;
 181                 int new_stride = num;
 182
 183                 if (new_stride > MAX_STRIDE_LENGTH)
 184                         new_stride = MAX_STRIDE_LENGTH;
 185                 p = realloc(buf, fs->blocksize * new_stride);
 186                 if (!p)
 187                         return EXT2_ET_NO_MEMORY;
 188                 buf = p;
 189                 stride_length = new_stride;
 190                 memset(buf, 0, fs->blocksize * stride_length);
 191         }
 192         /* OK, do the write loop */
 193         j=0;
 194         while (j < num) {
 195                 if (blk % stride_length) {
 196                         count = stride_length - (blk % stride_length);
 197                         if (count > (num - j))
 198                                 count = num - j;
 199                 } else {
 200                         count = num - j;
 201                         if (count > stride_length)
 202                                 count = stride_length;
 203                 }
 204                 retval = io_channel_write_blk64(fs->io, blk, count, buf);
 205                 if (retval) {
 206                         if (ret_count)
 207                                 *ret_count = count;
 208                         if (ret_blk)
 209                                 *ret_blk = blk;
 210                         return retval;
 211                 }
 212                 j += count; blk += count;
 213         }
 214         return 0;
 215 }
 216
 217 errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num,
 218                              blk_t *ret_blk, int *ret_count)
 219 {
 220         blk64_t ret_blk2;
 221         errcode_t retval;
 222
 223         retval = ext2fs_zero_blocks2(fs, blk, num, &ret_blk2, ret_count);
 224         if (retval)
 225                 *ret_blk = (blk_t) ret_blk2;
 226         return retval;
 227 }
 228
 229 /*
 230  * Helper function for creating the journal using direct I/O routines
 231  */
 232 struct mkjournal_struct {
 233         int             num_blocks;
 234         int             newblocks;
 235         blk64_t         goal;
 236         blk64_t         blk_to_zero;
 237         int             zero_count;
 238         int             flags;
 239         char            *buf;
 240         errcode_t       err;
 241 };
 242
 243 static int mkjournal_proc(ext2_filsys   fs,
 244                           blk64_t       *blocknr,
 245                           e2_blkcnt_t   blockcnt,
 246                           blk64_t       ref_block EXT2FS_ATTR((unused)),
 247                           int           ref_offset EXT2FS_ATTR((unused)),
 248                           void          *priv_data)
 249 {
 250         struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
 251         blk64_t new_blk;
 252         errcode_t       retval;
 253
 254         if (*blocknr) {
 255                 es->goal = *blocknr;
 256                 return 0;
 257         }
 258         if (blockcnt &&
 259             (EXT2FS_B2C(fs, es->goal) == EXT2FS_B2C(fs, es->goal+1)))
 260                 new_blk = es->goal+1;
 261         else {
 262                 es->goal &= ~EXT2FS_CLUSTER_MASK(fs);
 263                 retval = ext2fs_new_block2(fs, es->goal, 0, &new_blk);
 264                 if (retval) {
 265                         es->err = retval;
 266                         return BLOCK_ABORT;
 267                 }
 268                 ext2fs_block_alloc_stats2(fs, new_blk, +1);
 269                 es->newblocks++;
 270         }
 271         if (blockcnt >= 0)
 272                 es->num_blocks--;
 273
 274         retval = 0;
 275         if (blockcnt <= 0)
 276                 retval = io_channel_write_blk64(fs->io, new_blk, 1, es->buf);
 277         else if (!(es->flags & EXT2_MKJOURNAL_LAZYINIT)) {
 278                 if (es->zero_count) {
 279                         if ((es->blk_to_zero + es->zero_count == new_blk) &&
 280                             (es->zero_count < 1024))
 281                                 es->zero_count++;
 282                         else {
 283                                 retval = ext2fs_zero_blocks2(fs,
 284                                                              es->blk_to_zero,
 285                                                              es->zero_count,
 286                                                              0, 0);
 287                                 es->zero_count = 0;
 288                         }
 289                 }
 290                 if (es->zero_count == 0) {
 291                         es->blk_to_zero = new_blk;
 292                         es->zero_count = 1;
 293                 }
 294         }
 295
 296         if (blockcnt == 0)
 297                 memset(es->buf, 0, fs->blocksize);
 298
 299         if (retval) {
 300                 es->err = retval;
 301                 return BLOCK_ABORT;
 302         }
 303         *blocknr = es->goal = new_blk;
 304
 305         if (es->num_blocks == 0)
 306                 return (BLOCK_CHANGED | BLOCK_ABORT);
 307         else
 308                 return BLOCK_CHANGED;
 309
 310 }
 311
 312 /*
 313  * Calculate the initial goal block to be roughly at the middle of the
 314  * filesystem.  Pick a group that has the largest number of free
 315  * blocks.
 316  */
 317 static blk64_t get_midpoint_journal_block(ext2_filsys fs)
 318 {
 319         dgrp_t  group, start, end, i, log_flex;
 320
 321         group = ext2fs_group_of_blk2(fs, (ext2fs_blocks_count(fs->super) -
 322                                          fs->super->s_first_data_block) / 2);
 323         log_flex = 1 << fs->super->s_log_groups_per_flex;
 324         if (fs->super->s_log_groups_per_flex && (group > log_flex)) {
 325                 group = group & ~(log_flex - 1);
 326                 while ((group < fs->group_desc_count) &&
 327                        ext2fs_bg_free_blocks_count(fs, group) == 0)
 328                         group++;
 329                 if (group == fs->group_desc_count)
 330                         group = 0;
 331                 start = group;
 332         } else
 333                 start = (group > 0) ? group-1 : group;
 334         end = ((group+1) < fs->group_desc_count) ? group+1 : group;
 335         group = start;
 336         for (i = start + 1; i <= end; i++)
 337                 if (ext2fs_bg_free_blocks_count(fs, i) >
 338                     ext2fs_bg_free_blocks_count(fs, group))
 339                         group = i;
 340         return ext2fs_group_first_block2(fs, group);
 341 }
 342
 343 /*
 344  * This function creates a journal using direct I/O routines.
 345  */
 346 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
 347                                      blk_t num_blocks, blk64_t goal, int flags)
 348 {
 349         char                    *buf;
 350         errcode_t               retval;
 351         struct ext2_inode       inode;
 352         unsigned long long      inode_size;
 353         struct mkjournal_struct es;
 354
 355         if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags,
 356                                                        &buf)))
 357                 return retval;
 358
 359         if ((retval = ext2fs_read_bitmaps(fs)))
 360                 goto out2;
 361
 362         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 363                 goto out2;
 364
 365         if (inode.i_blocks > 0) {
 366                 retval = EEXIST;
 367                 goto out2;
 368         }
 369
 370         es.num_blocks = num_blocks;
 371         es.newblocks = 0;
 372         es.buf = buf;
 373         es.err = 0;
 374         es.flags = flags;
 375         es.zero_count = 0;
 376         es.goal = (goal != ~0ULL) ? goal : get_midpoint_journal_block(fs);
 377
 378         if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) {
 379                 inode.i_flags |= EXT4_EXTENTS_FL;
 380                 if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
 381                         goto out2;
 382         }
 383
 384         retval = ext2fs_block_iterate3(fs, journal_ino, BLOCK_FLAG_APPEND,
 385                                        0, mkjournal_proc, &es);
 386         if (retval)
 387                 goto out2;
 388         if (es.err) {
 389                 retval = es.err;
 390                 goto out2;
 391         }
 392         if (es.zero_count) {
 393                 retval = ext2fs_zero_blocks2(fs, es.blk_to_zero,
 394                                             es.zero_count, 0, 0);
 395                 if (retval)
 396                         goto out2;
 397         }
 398
 399         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 400                 goto out2;
 401
 402         inode_size = (unsigned long long)fs->blocksize * num_blocks;
 403         ext2fs_iblk_add_blocks(fs, &inode, es.newblocks);
 404         inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
 405         inode.i_links_count = 1;
 406         inode.i_mode = LINUX_S_IFREG | 0600;
 407         retval = ext2fs_inode_size_set(fs, &inode, inode_size);
 408         if (retval)
 409                 goto out2;
 410
 411         if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode)))
 412                 goto out2;
 413         retval = 0;
 414
 415         memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
 416         fs->super->s_jnl_blocks[15] = inode.i_size_high;
 417         fs->super->s_jnl_blocks[16] = inode.i_size;
 418         fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
 419         ext2fs_mark_super_dirty(fs);
 420
 421 out2:
 422         ext2fs_free_mem(&buf);
 423         return retval;
 424 }
 425
 426 /*
 427  * Find a reasonable journal file size (in blocks) given the number of blocks
 428  * in the filesystem.  For very small filesystems, it is not reasonable to
 429  * have a journal that fills more than half of the filesystem.
 430  */
 431 int ext2fs_default_journal_size(__u64 num_blocks)
 432 {
 433         if (num_blocks < 2048)
 434                 return -1;
 435         if (num_blocks < 32768)
 436                 return (1024);
 437         if (num_blocks < 256*1024)
 438                 return (4096);
 439         if (num_blocks < 512*1024)
 440                 return (8192);
 441         if (num_blocks < 1024*1024)
 442                 return (16384);
 443         return 32768;
 444 }
 445
 446 int ext2fs_journal_sb_start(int blocksize)
 447 {
 448         if (blocksize == EXT2_MIN_BLOCK_SIZE)
 449                 return 2;
 450         return 1;
 451 }
 452
 453 /*
 454  * This function adds a journal device to a filesystem
 455  */
 456 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
 457 {
 458         struct stat     st;
 459         errcode_t       retval;
 460         char            buf[SUPERBLOCK_SIZE];
 461         journal_superblock_t    *jsb;
 462         int             start;
 463         __u32           i, nr_users;
 464
 465         /* Make sure the device exists and is a block device */
 466         if (stat(journal_dev->device_name, &st) < 0)
 467                 return errno;
 468
 469         if (!S_ISBLK(st.st_mode))
 470                 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
 471
 472         /* Get the journal superblock */
 473         start = ext2fs_journal_sb_start(journal_dev->blocksize);
 474         if ((retval = io_channel_read_blk64(journal_dev->io, start,
 475                                             -SUPERBLOCK_SIZE,
 476                                             buf)))
 477                 return retval;
 478
 479         jsb = (journal_superblock_t *) buf;
 480         if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
 481             (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
 482                 return EXT2_ET_NO_JOURNAL_SB;
 483
 484         if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
 485                 return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 486
 487         /* Check and see if this filesystem has already been added */
 488         nr_users = ntohl(jsb->s_nr_users);
 489         for (i=0; i < nr_users; i++) {
 490                 if (memcmp(fs->super->s_uuid,
 491                            &jsb->s_users[i*16], 16) == 0)
 492                         break;
 493         }
 494         if (i >= nr_users) {
 495                 memcpy(&jsb->s_users[nr_users*16],
 496                        fs->super->s_uuid, 16);
 497                 jsb->s_nr_users = htonl(nr_users+1);
 498         }
 499
 500         /* Writeback the journal superblock */
 501         if ((retval = io_channel_write_blk64(journal_dev->io, start,
 502                                             -SUPERBLOCK_SIZE, buf)))
 503                 return retval;
 504
 505         fs->super->s_journal_inum = 0;
 506         fs->super->s_journal_dev = st.st_rdev;
 507         memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
 508                sizeof(fs->super->s_journal_uuid));
 509         memset(fs->super->s_jnl_blocks, 0, sizeof(fs->super->s_jnl_blocks));
 510         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 511         ext2fs_mark_super_dirty(fs);
 512         return 0;
 513 }
 514
 515 /*
 516  * This function adds a journal inode to a filesystem, using either
 517  * POSIX routines if the filesystem is mounted, or using direct I/O
 518  * functions if it is not.
 519  */
 520 errcode_t ext2fs_add_journal_inode2(ext2_filsys fs, blk_t num_blocks,
 521                                     blk64_t goal, int flags)
 522 {
 523         errcode_t               retval;
 524         ext2_ino_t              journal_ino;
 525         struct stat             st;
 526         char                    jfile[1024];
 527         int                     mount_flags;
 528         int                     fd = -1;
 529
 530         if (flags & EXT2_MKJOURNAL_NO_MNT_CHECK)
 531                 mount_flags = 0;
 532         else if ((retval = ext2fs_check_mount_point(fs->device_name,
 533                                                     &mount_flags,
 534                                                     jfile, sizeof(jfile)-10)))
 535                 return retval;
 536
 537         if (mount_flags & EXT2_MF_MOUNTED) {
 538 #if HAVE_EXT2_IOCTLS
 539                 int f = 0;
 540 #endif
 541                 strcat(jfile, "/.journal");
 542
 543                 /*
 544                  * If .../.journal already exists, make sure any
 545                  * immutable or append-only flags are cleared.
 546                  */
 547 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 548                 (void) chflags (jfile, 0);
 549 #else
 550 #if HAVE_EXT2_IOCTLS
 551                 fd = open(jfile, O_RDONLY);
 552                 if (fd >= 0) {
 553                         retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 554                         close(fd);
 555                         if (retval)
 556                                 return retval;
 557                 }
 558 #endif
 559 #endif
 560
 561                 /* Create the journal file */
 562                 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
 563                         return errno;
 564
 565                 /* Note that we can't do lazy journal initialization for mounted
 566                  * filesystems, since the zero writing is also allocating the
 567                  * journal blocks.  We could use fallocate, but not all kernels
 568                  * support that, and creating a journal on a mounted ext2
 569                  * filesystems is extremely rare these days...  Ignore it. */
 570                 flags &= ~EXT2_MKJOURNAL_LAZYINIT;
 571
 572                 if ((retval = write_journal_file(fs, jfile, num_blocks, flags)))
 573                         goto errout;
 574
 575                 /* Get inode number of the journal file */
 576                 if (fstat(fd, &st) < 0) {
 577                         retval = errno;
 578                         goto errout;
 579                 }
 580
 581 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 582                 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
 583 #else
 584 #if HAVE_EXT2_IOCTLS
 585                 if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) {
 586                         retval = errno;
 587                         goto errout;
 588                 }
 589                 f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
 590                 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 591 #endif
 592 #endif
 593                 if (retval) {
 594                         retval = errno;
 595                         goto errout;
 596                 }
 597
 598                 if (close(fd) < 0) {
 599                         retval = errno;
 600                         fd = -1;
 601                         goto errout;
 602                 }
 603                 journal_ino = st.st_ino;
 604                 memset(fs->super->s_jnl_blocks, 0,
 605                        sizeof(fs->super->s_jnl_blocks));
 606         } else {
 607                 if ((mount_flags & EXT2_MF_BUSY) &&
 608                     !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
 609                         retval = EBUSY;
 610                         goto errout;
 611                 }
 612                 journal_ino = EXT2_JOURNAL_INO;
 613                 if ((retval = write_journal_inode(fs, journal_ino,
 614                                                   num_blocks, goal, flags)))
 615                         return retval;
 616         }
 617
 618         fs->super->s_journal_inum = journal_ino;
 619         fs->super->s_journal_dev = 0;
 620         memset(fs->super->s_journal_uuid, 0,
 621                sizeof(fs->super->s_journal_uuid));
 622         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 623
 624         ext2fs_mark_super_dirty(fs);
 625         return 0;
 626 errout:
 627         if (fd >= 0)
 628                 close(fd);
 629         return retval;
 630 }
 631
 632 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t num_blocks, int flags)
 633 {
 634         return ext2fs_add_journal_inode2(fs, num_blocks, ~0ULL, flags);
 635 }
 636
 637
 638 #ifdef DEBUG
 639 main(int argc, char **argv)
 640 {
 641         errcode_t       retval;
 642         char            *device_name;
 643         ext2_filsys     fs;
 644
 645         if (argc < 2) {
 646                 fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
 647                 exit(1);
 648         }
 649         device_name = argv[1];
 650
 651         retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
 652                               unix_io_manager, &fs);
 653         if (retval) {
 654                 com_err(argv[0], retval, "while opening %s", device_name);
 655                 exit(1);
 656         }
 657
 658         retval = ext2fs_add_journal_inode(fs, JFS_MIN_JOURNAL_BLOCKS, 0);
 659         if (retval) {
 660                 com_err(argv[0], retval, "while adding journal to %s",
 661                         device_name);
 662                 exit(1);
 663         }
 664         retval = ext2fs_flush(fs);
 665         if (retval) {
 666                 printf("Warning, had trouble writing out superblocks.\n");
 667         }
 668         ext2fs_close_free(&fs);
 669         exit(0);
 670
 671 }
 672 #endif