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 <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           goal;
 202         blk_t           blk_to_zero;
 203         int             zero_count;
 204         char            *buf;
 205         errcode_t       err;
 206 };
 207
 208 static int mkjournal_proc(ext2_filsys   fs,
 209                            blk_t        *blocknr,
 210                            e2_blkcnt_t  blockcnt,
 211                            blk_t        ref_block EXT2FS_ATTR((unused)),
 212                            int          ref_offset EXT2FS_ATTR((unused)),
 213                            void         *priv_data)
 214 {
 215         struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
 216         blk_t   new_blk;
 217         errcode_t       retval;
 218
 219         if (*blocknr) {
 220                 es->goal = *blocknr;
 221                 return 0;
 222         }
 223         retval = ext2fs_new_block(fs, es->goal, 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 = es->goal = new_blk;
 262         ext2fs_block_alloc_stats(fs, new_blk, +1);
 263
 264         if (es->num_blocks == 0)
 265                 return (BLOCK_CHANGED | BLOCK_ABORT);
 266         else
 267                 return BLOCK_CHANGED;
 268
 269 }
 270
 271 /*
 272  * This function creates a journal using direct I/O routines.
 273  */
 274 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
 275                                      blk_t size, int flags)
 276 {
 277         char                    *buf;
 278         dgrp_t                  group, start, end, i, log_flex;
 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         if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) {
 302                 inode.i_flags |= EXT4_EXTENTS_FL;
 303                 if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
 304                         return retval;
 305         }
 306
 307         /*
 308          * Set the initial goal block to be roughly at the middle of
 309          * the filesystem.  Pick a group that has the largest number
 310          * of free blocks.
 311          */
 312         group = ext2fs_group_of_blk(fs, (fs->super->s_blocks_count -
 313                                          fs->super->s_first_data_block) / 2);
 314         log_flex = 1 << fs->super->s_log_groups_per_flex;
 315         if (fs->super->s_log_groups_per_flex && (group > log_flex)) {
 316                 group = group & ~(log_flex - 1);
 317                 while ((group < fs->group_desc_count) &&
 318                        fs->group_desc[group].bg_free_blocks_count == 0)
 319                         group++;
 320                 if (group == fs->group_desc_count)
 321                         group = 0;
 322                 start = group;
 323         } else
 324                 start = (group > 0) ? group-1 : group;
 325         end = ((group+1) < fs->group_desc_count) ? group+1 : group;
 326         group = start;
 327         for (i=start+1; i <= end; i++)
 328                 if (fs->group_desc[i].bg_free_blocks_count >
 329                     fs->group_desc[group].bg_free_blocks_count)
 330                         group = i;
 331
 332         es.goal = (fs->super->s_blocks_per_group * group) +
 333                 fs->super->s_first_data_block;
 334
 335         retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
 336                                        0, mkjournal_proc, &es);
 337         if (es.err) {
 338                 retval = es.err;
 339                 goto errout;
 340         }
 341         if (es.zero_count) {
 342                 retval = ext2fs_zero_blocks(fs, es.blk_to_zero,
 343                                             es.zero_count, 0, 0);
 344                 if (retval)
 345                         goto errout;
 346         }
 347
 348         if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
 349                 goto errout;
 350
 351         inode.i_size += fs->blocksize * size;
 352         ext2fs_iblk_add_blocks(fs, &inode, es.newblocks);
 353         inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
 354         inode.i_links_count = 1;
 355         inode.i_mode = LINUX_S_IFREG | 0600;
 356
 357         if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode)))
 358                 goto errout;
 359         retval = 0;
 360
 361         memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
 362         fs->super->s_jnl_blocks[16] = inode.i_size;
 363         fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
 364         ext2fs_mark_super_dirty(fs);
 365
 366 errout:
 367         ext2fs_free_mem(&buf);
 368         return retval;
 369 }
 370
 371 /*
 372  * Find a reasonable journal file size (in blocks) given the number of blocks
 373  * in the filesystem.  For very small filesystems, it is not reasonable to
 374  * have a journal that fills more than half of the filesystem.
 375  */
 376 int ext2fs_default_journal_size(__u64 blocks)
 377 {
 378         if (blocks < 2048)
 379                 return -1;
 380         if (blocks < 32768)
 381                 return (1024);
 382         if (blocks < 256*1024)
 383                 return (4096);
 384         if (blocks < 512*1024)
 385                 return (8192);
 386         if (blocks < 1024*1024)
 387                 return (16384);
 388         return 32768;
 389 }
 390
 391 /*
 392  * This function adds a journal device to a filesystem
 393  */
 394 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
 395 {
 396         struct stat     st;
 397         errcode_t       retval;
 398         char            buf[1024];
 399         journal_superblock_t    *jsb;
 400         int             start;
 401         __u32           i, nr_users;
 402
 403         /* Make sure the device exists and is a block device */
 404         if (stat(journal_dev->device_name, &st) < 0)
 405                 return errno;
 406
 407         if (!S_ISBLK(st.st_mode))
 408                 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
 409
 410         /* Get the journal superblock */
 411         start = 1;
 412         if (journal_dev->blocksize == 1024)
 413                 start++;
 414         if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
 415                 return retval;
 416
 417         jsb = (journal_superblock_t *) buf;
 418         if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
 419             (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
 420                 return EXT2_ET_NO_JOURNAL_SB;
 421
 422         if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
 423                 return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
 424
 425         /* Check and see if this filesystem has already been added */
 426         nr_users = ntohl(jsb->s_nr_users);
 427         for (i=0; i < nr_users; i++) {
 428                 if (memcmp(fs->super->s_uuid,
 429                            &jsb->s_users[i*16], 16) == 0)
 430                         break;
 431         }
 432         if (i >= nr_users) {
 433                 memcpy(&jsb->s_users[nr_users*16],
 434                        fs->super->s_uuid, 16);
 435                 jsb->s_nr_users = htonl(nr_users+1);
 436         }
 437
 438         /* Writeback the journal superblock */
 439         if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
 440                 return retval;
 441
 442         fs->super->s_journal_inum = 0;
 443         fs->super->s_journal_dev = st.st_rdev;
 444         memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
 445                sizeof(fs->super->s_journal_uuid));
 446         fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
 447         ext2fs_mark_super_dirty(fs);
 448         return 0;
 449 }
 450
 451 /*
 452  * This function adds a journal inode to a filesystem, using either
 453  * POSIX routines if the filesystem is mounted, or using direct I/O
 454  * functions if it is not.
 455  */
 456 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
 457 {
 458         errcode_t               retval;
 459         ext2_ino_t              journal_ino;
 460         struct stat             st;
 461         char                    jfile[1024];
 462         int                     mount_flags, f;
 463         int                     fd = -1;
 464
 465         if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
 466                                                jfile, sizeof(jfile)-10)))
 467                 return retval;
 468
 469         if (mount_flags & EXT2_MF_MOUNTED) {
 470                 strcat(jfile, "/.journal");
 471
 472                 /*
 473                  * If .../.journal already exists, make sure any
 474                  * immutable or append-only flags are cleared.
 475                  */
 476 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 477                 (void) chflags (jfile, 0);
 478 #else
 479 #if HAVE_EXT2_IOCTLS
 480                 fd = open(jfile, O_RDONLY);
 481                 if (fd >= 0) {
 482                         f = 0;
 483                         ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 484                         close(fd);
 485                 }
 486 #endif
 487 #endif
 488
 489                 /* Create the journal file */
 490                 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
 491                         return errno;
 492
 493                 if ((retval = write_journal_file(fs, jfile, size, flags)))
 494                         goto errout;
 495
 496                 /* Get inode number of the journal file */
 497                 if (fstat(fd, &st) < 0) {
 498                         retval = errno;
 499                         goto errout;
 500                 }
 501
 502 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
 503                 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
 504 #else
 505 #if HAVE_EXT2_IOCTLS
 506                 if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) {
 507                         retval = errno;
 508                         goto errout;
 509                 }
 510                 f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
 511                 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
 512 #endif
 513 #endif
 514                 if (retval) {
 515                         retval = errno;
 516                         goto errout;
 517                 }
 518
 519                 if (close(fd) < 0) {
 520                         retval = errno;
 521                         fd = -1;
 522                         goto errout;
 523                 }
 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