mkjournal.c revision 6c54689fadc3fe0b0bcae2cc93946cb7a28b9f15
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 */ 44errcode_t ext2fs_create_journal_superblock(ext2_filsys fs, 45 __u32 num_blocks, int flags, 46 char **ret_jsb) 47{ 48 errcode_t retval; 49 journal_superblock_t *jsb; 50 51 if (num_blocks < 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(num_blocks); 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 */ 92static errcode_t write_journal_file(ext2_filsys fs, char *filename, 93 blk_t num_blocks, 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, num_blocks, flags, 101 &buf))) 102 return retval; 103 104 /* Open the device or journal file */ 105 if ((fd = open(filename, O_WRONLY)) < 0) { 106 retval = errno; 107 goto errfree; 108 } 109 110 /* Write the superblock out */ 111 retval = EXT2_ET_SHORT_WRITE; 112 ret_size = write(fd, buf, fs->blocksize); 113 if (ret_size < 0) { 114 retval = errno; 115 goto errout; 116 } 117 if (ret_size != (int) fs->blocksize) 118 goto errout; 119 memset(buf, 0, fs->blocksize); 120 121 if (flags & EXT2_MKJOURNAL_LAZYINIT) 122 goto success; 123 124 for (i = 1; i < num_blocks; i++) { 125 ret_size = write(fd, buf, fs->blocksize); 126 if (ret_size < 0) { 127 retval = errno; 128 goto errout; 129 } 130 if (ret_size != (int) fs->blocksize) 131 goto errout; 132 } 133 134success: 135 retval = 0; 136errout: 137 close(fd); 138errfree: 139 ext2fs_free_mem(&buf); 140 return retval; 141} 142 143/* 144 * Convenience function which zeros out _num_ blocks starting at 145 * _blk_. In case of an error, the details of the error is returned 146 * via _ret_blk_ and _ret_count_ if they are non-NULL pointers. 147 * Returns 0 on success, and an error code on an error. 148 * 149 * As a special case, if the first argument is NULL, then it will 150 * attempt to free the static zeroizing buffer. (This is to keep 151 * programs that check for memory leaks happy.) 152 */ 153#define STRIDE_LENGTH 8 154errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, 155 blk64_t *ret_blk, int *ret_count) 156{ 157 int j, count; 158 static char *buf; 159 errcode_t retval; 160 161 /* If fs is null, clean up the static buffer and return */ 162 if (!fs) { 163 if (buf) { 164 free(buf); 165 buf = 0; 166 } 167 return 0; 168 } 169 /* Allocate the zeroizing buffer if necessary */ 170 if (!buf) { 171 buf = malloc(fs->blocksize * STRIDE_LENGTH); 172 if (!buf) 173 return ENOMEM; 174 memset(buf, 0, fs->blocksize * STRIDE_LENGTH); 175 } 176 /* OK, do the write loop */ 177 j=0; 178 while (j < num) { 179 if (blk % STRIDE_LENGTH) { 180 count = STRIDE_LENGTH - (blk % STRIDE_LENGTH); 181 if (count > (num - j)) 182 count = num - j; 183 } else { 184 count = num - j; 185 if (count > STRIDE_LENGTH) 186 count = STRIDE_LENGTH; 187 } 188 retval = io_channel_write_blk64(fs->io, blk, count, buf); 189 if (retval) { 190 if (ret_count) 191 *ret_count = count; 192 if (ret_blk) 193 *ret_blk = blk; 194 return retval; 195 } 196 j += count; blk += count; 197 } 198 return 0; 199} 200 201errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num, 202 blk_t *ret_blk, int *ret_count) 203{ 204 blk64_t ret_blk2; 205 errcode_t retval; 206 207 retval = ext2fs_zero_blocks2(fs, blk, num, &ret_blk2, ret_count); 208 if (retval) 209 *ret_blk = (blk_t) ret_blk2; 210 return retval; 211} 212 213/* 214 * Helper function for creating the journal using direct I/O routines 215 */ 216struct mkjournal_struct { 217 int num_blocks; 218 int newblocks; 219 blk64_t goal; 220 blk64_t blk_to_zero; 221 int zero_count; 222 int flags; 223 char *buf; 224 errcode_t err; 225}; 226 227static int mkjournal_proc(ext2_filsys fs, 228 blk64_t *blocknr, 229 e2_blkcnt_t blockcnt, 230 blk64_t ref_block EXT2FS_ATTR((unused)), 231 int ref_offset EXT2FS_ATTR((unused)), 232 void *priv_data) 233{ 234 struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data; 235 blk64_t new_blk; 236 errcode_t retval; 237 238 if (*blocknr) { 239 es->goal = *blocknr; 240 return 0; 241 } 242 if (blockcnt && 243 (EXT2FS_B2C(fs, es->goal) == EXT2FS_B2C(fs, es->goal+1))) 244 new_blk = es->goal+1; 245 else { 246 es->goal &= ~EXT2FS_CLUSTER_MASK(fs); 247 retval = ext2fs_new_block2(fs, es->goal, 0, &new_blk); 248 if (retval) { 249 es->err = retval; 250 return BLOCK_ABORT; 251 } 252 } 253 if (blockcnt >= 0) 254 es->num_blocks--; 255 256 es->newblocks++; 257 retval = 0; 258 if (blockcnt <= 0) 259 retval = io_channel_write_blk64(fs->io, new_blk, 1, es->buf); 260 else if (!(es->flags & EXT2_MKJOURNAL_LAZYINIT)) { 261 if (es->zero_count) { 262 if ((es->blk_to_zero + es->zero_count == new_blk) && 263 (es->zero_count < 1024)) 264 es->zero_count++; 265 else { 266 retval = ext2fs_zero_blocks2(fs, 267 es->blk_to_zero, 268 es->zero_count, 269 0, 0); 270 es->zero_count = 0; 271 } 272 } 273 if (es->zero_count == 0) { 274 es->blk_to_zero = new_blk; 275 es->zero_count = 1; 276 } 277 } 278 279 if (blockcnt == 0) 280 memset(es->buf, 0, fs->blocksize); 281 282 if (retval) { 283 es->err = retval; 284 return BLOCK_ABORT; 285 } 286 *blocknr = es->goal = new_blk; 287 ext2fs_block_alloc_stats2(fs, new_blk, +1); 288 289 if (es->num_blocks == 0) 290 return (BLOCK_CHANGED | BLOCK_ABORT); 291 else 292 return BLOCK_CHANGED; 293 294} 295 296/* 297 * This function creates a journal using direct I/O routines. 298 */ 299static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino, 300 blk_t num_blocks, int flags) 301{ 302 char *buf; 303 dgrp_t group, start, end, i, log_flex; 304 errcode_t retval; 305 struct ext2_inode inode; 306 unsigned long long inode_size; 307 struct mkjournal_struct es; 308 309 if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags, 310 &buf))) 311 return retval; 312 313 if ((retval = ext2fs_read_bitmaps(fs))) 314 return retval; 315 316 if ((retval = ext2fs_read_inode(fs, journal_ino, &inode))) 317 return retval; 318 319 if (inode.i_blocks > 0) 320 return EEXIST; 321 322 es.num_blocks = num_blocks; 323 es.newblocks = 0; 324 es.buf = buf; 325 es.err = 0; 326 es.flags = flags; 327 es.zero_count = 0; 328 329 if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) { 330 inode.i_flags |= EXT4_EXTENTS_FL; 331 if ((retval = ext2fs_write_inode(fs, journal_ino, &inode))) 332 return retval; 333 } 334 335 /* 336 * Set the initial goal block to be roughly at the middle of 337 * the filesystem. Pick a group that has the largest number 338 * of free blocks. 339 */ 340 group = ext2fs_group_of_blk2(fs, (ext2fs_blocks_count(fs->super) - 341 fs->super->s_first_data_block) / 2); 342 log_flex = 1 << fs->super->s_log_groups_per_flex; 343 if (fs->super->s_log_groups_per_flex && (group > log_flex)) { 344 group = group & ~(log_flex - 1); 345 while ((group < fs->group_desc_count) && 346 ext2fs_bg_free_blocks_count(fs, group) == 0) 347 group++; 348 if (group == fs->group_desc_count) 349 group = 0; 350 start = group; 351 } else 352 start = (group > 0) ? group-1 : group; 353 end = ((group+1) < fs->group_desc_count) ? group+1 : group; 354 group = start; 355 for (i=start+1; i <= end; i++) 356 if (ext2fs_bg_free_blocks_count(fs, i) > 357 ext2fs_bg_free_blocks_count(fs, group)) 358 group = i; 359 360 es.goal = (fs->super->s_blocks_per_group * group) + 361 fs->super->s_first_data_block; 362 363 retval = ext2fs_block_iterate3(fs, journal_ino, BLOCK_FLAG_APPEND, 364 0, mkjournal_proc, &es); 365 if (es.err) { 366 retval = es.err; 367 goto errout; 368 } 369 if (es.zero_count) { 370 retval = ext2fs_zero_blocks2(fs, es.blk_to_zero, 371 es.zero_count, 0, 0); 372 if (retval) 373 goto errout; 374 } 375 376 if ((retval = ext2fs_read_inode(fs, journal_ino, &inode))) 377 goto errout; 378 379 inode_size = (unsigned long long)fs->blocksize * num_blocks; 380 inode.i_size = inode_size & 0xFFFFFFFF; 381 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF; 382 if (inode.i_size_high) 383 fs->super->s_feature_ro_compat |= 384 EXT2_FEATURE_RO_COMPAT_LARGE_FILE; 385 ext2fs_iblk_add_blocks(fs, &inode, es.newblocks); 386 inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0); 387 inode.i_links_count = 1; 388 inode.i_mode = LINUX_S_IFREG | 0600; 389 390 if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode))) 391 goto errout; 392 retval = 0; 393 394 memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4); 395 fs->super->s_jnl_blocks[15] = inode.i_size_high; 396 fs->super->s_jnl_blocks[16] = inode.i_size; 397 fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS; 398 ext2fs_mark_super_dirty(fs); 399 400errout: 401 ext2fs_zero_blocks2(0, 0, 0, 0, 0); 402 ext2fs_free_mem(&buf); 403 return retval; 404} 405 406/* 407 * Find a reasonable journal file size (in blocks) given the number of blocks 408 * in the filesystem. For very small filesystems, it is not reasonable to 409 * have a journal that fills more than half of the filesystem. 410 */ 411int ext2fs_default_journal_size(__u64 num_blocks) 412{ 413 if (num_blocks < 2048) 414 return -1; 415 if (num_blocks < 32768) 416 return (1024); 417 if (num_blocks < 256*1024) 418 return (4096); 419 if (num_blocks < 512*1024) 420 return (8192); 421 if (num_blocks < 1024*1024) 422 return (16384); 423 return 32768; 424} 425 426/* 427 * This function adds a journal device to a filesystem 428 */ 429errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev) 430{ 431 struct stat st; 432 errcode_t retval; 433 char buf[1024]; 434 journal_superblock_t *jsb; 435 int start; 436 __u32 i, nr_users; 437 438 /* Make sure the device exists and is a block device */ 439 if (stat(journal_dev->device_name, &st) < 0) 440 return errno; 441 442 if (!S_ISBLK(st.st_mode)) 443 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */ 444 445 /* Get the journal superblock */ 446 start = 1; 447 if (journal_dev->blocksize == 1024) 448 start++; 449 if ((retval = io_channel_read_blk64(journal_dev->io, start, -1024, 450 buf))) 451 return retval; 452 453 jsb = (journal_superblock_t *) buf; 454 if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) || 455 (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2))) 456 return EXT2_ET_NO_JOURNAL_SB; 457 458 if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize) 459 return EXT2_ET_UNEXPECTED_BLOCK_SIZE; 460 461 /* Check and see if this filesystem has already been added */ 462 nr_users = ntohl(jsb->s_nr_users); 463 for (i=0; i < nr_users; i++) { 464 if (memcmp(fs->super->s_uuid, 465 &jsb->s_users[i*16], 16) == 0) 466 break; 467 } 468 if (i >= nr_users) { 469 memcpy(&jsb->s_users[nr_users*16], 470 fs->super->s_uuid, 16); 471 jsb->s_nr_users = htonl(nr_users+1); 472 } 473 474 /* Writeback the journal superblock */ 475 if ((retval = io_channel_write_blk64(journal_dev->io, start, -1024, buf))) 476 return retval; 477 478 fs->super->s_journal_inum = 0; 479 fs->super->s_journal_dev = st.st_rdev; 480 memcpy(fs->super->s_journal_uuid, jsb->s_uuid, 481 sizeof(fs->super->s_journal_uuid)); 482 fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL; 483 ext2fs_mark_super_dirty(fs); 484 return 0; 485} 486 487/* 488 * This function adds a journal inode to a filesystem, using either 489 * POSIX routines if the filesystem is mounted, or using direct I/O 490 * functions if it is not. 491 */ 492errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t num_blocks, int flags) 493{ 494 errcode_t retval; 495 ext2_ino_t journal_ino; 496 struct stat st; 497 char jfile[1024]; 498 int mount_flags, f; 499 int fd = -1; 500 501 if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags, 502 jfile, sizeof(jfile)-10))) 503 return retval; 504 505 if (mount_flags & EXT2_MF_MOUNTED) { 506 strcat(jfile, "/.journal"); 507 508 /* 509 * If .../.journal already exists, make sure any 510 * immutable or append-only flags are cleared. 511 */ 512#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP) 513 (void) chflags (jfile, 0); 514#else 515#if HAVE_EXT2_IOCTLS 516 fd = open(jfile, O_RDONLY); 517 if (fd >= 0) { 518 f = 0; 519 ioctl(fd, EXT2_IOC_SETFLAGS, &f); 520 close(fd); 521 } 522#endif 523#endif 524 525 /* Create the journal file */ 526 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0) 527 return errno; 528 529 /* Note that we can't do lazy journal initialization for mounted 530 * filesystems, since the zero writing is also allocating the 531 * journal blocks. We could use fallocate, but not all kernels 532 * support that, and creating a journal on a mounted ext2 533 * filesystems is extremely rare these days... Ignore it. */ 534 flags &= ~EXT2_MKJOURNAL_LAZYINIT; 535 536 if ((retval = write_journal_file(fs, jfile, num_blocks, flags))) 537 goto errout; 538 539 /* Get inode number of the journal file */ 540 if (fstat(fd, &st) < 0) { 541 retval = errno; 542 goto errout; 543 } 544 545#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP) 546 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE); 547#else 548#if HAVE_EXT2_IOCTLS 549 if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) { 550 retval = errno; 551 goto errout; 552 } 553 f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL; 554 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f); 555#endif 556#endif 557 if (retval) { 558 retval = errno; 559 goto errout; 560 } 561 562 if (close(fd) < 0) { 563 retval = errno; 564 fd = -1; 565 goto errout; 566 } 567 journal_ino = st.st_ino; 568 } else { 569 if ((mount_flags & EXT2_MF_BUSY) && 570 !(fs->flags & EXT2_FLAG_EXCLUSIVE)) { 571 retval = EBUSY; 572 goto errout; 573 } 574 journal_ino = EXT2_JOURNAL_INO; 575 if ((retval = write_journal_inode(fs, journal_ino, 576 num_blocks, flags))) 577 return retval; 578 } 579 580 fs->super->s_journal_inum = journal_ino; 581 fs->super->s_journal_dev = 0; 582 memset(fs->super->s_journal_uuid, 0, 583 sizeof(fs->super->s_journal_uuid)); 584 fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL; 585 586 ext2fs_mark_super_dirty(fs); 587 return 0; 588errout: 589 if (fd > 0) 590 close(fd); 591 return retval; 592} 593 594#ifdef DEBUG 595main(int argc, char **argv) 596{ 597 errcode_t retval; 598 char *device_name; 599 ext2_filsys fs; 600 601 if (argc < 2) { 602 fprintf(stderr, "Usage: %s filesystem\n", argv[0]); 603 exit(1); 604 } 605 device_name = argv[1]; 606 607 retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0, 608 unix_io_manager, &fs); 609 if (retval) { 610 com_err(argv[0], retval, "while opening %s", device_name); 611 exit(1); 612 } 613 614 retval = ext2fs_add_journal_inode(fs, 1024); 615 if (retval) { 616 com_err(argv[0], retval, "while adding journal to %s", 617 device_name); 618 exit(1); 619 } 620 retval = ext2fs_flush(fs); 621 if (retval) { 622 printf("Warning, had trouble writing out superblocks.\n"); 623 } 624 ext2fs_close(fs); 625 exit(0); 626 627} 628#endif 629