mkjournal.c revision 8d74ab767d0f97258fed40f2f2d862227545bcea
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 */ 45errcode_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 < 1024) 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 if (fs->blocksize == 1024) 79 jsb->s_first = htonl(3); 80 else 81 jsb->s_first = htonl(2); 82 } 83 84 *ret_jsb = (char *) jsb; 85 return 0; 86} 87 88/* 89 * This function writes a journal using POSIX routines. It is used 90 * for creating external journals and creating journals on live 91 * filesystems. 92 */ 93static errcode_t write_journal_file(ext2_filsys fs, char *filename, 94 blk_t num_blocks, int flags) 95{ 96 errcode_t retval; 97 char *buf = 0; 98 int fd, ret_size; 99 blk_t i; 100 101 if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags, 102 &buf))) 103 return retval; 104 105 /* Open the device or journal file */ 106 if ((fd = open(filename, O_WRONLY)) < 0) { 107 retval = errno; 108 goto errfree; 109 } 110 111 /* Write the superblock out */ 112 retval = EXT2_ET_SHORT_WRITE; 113 ret_size = write(fd, buf, fs->blocksize); 114 if (ret_size < 0) { 115 retval = errno; 116 goto errout; 117 } 118 if (ret_size != (int) fs->blocksize) 119 goto errout; 120 memset(buf, 0, fs->blocksize); 121 122 if (flags & EXT2_MKJOURNAL_LAZYINIT) 123 goto success; 124 125 for (i = 1; i < num_blocks; i++) { 126 ret_size = write(fd, buf, fs->blocksize); 127 if (ret_size < 0) { 128 retval = errno; 129 goto errout; 130 } 131 if (ret_size != (int) fs->blocksize) 132 goto errout; 133 } 134 135success: 136 retval = 0; 137errout: 138 close(fd); 139errfree: 140 ext2fs_free_mem(&buf); 141 return retval; 142} 143 144/* 145 * Convenience function which zeros out _num_ blocks starting at 146 * _blk_. In case of an error, the details of the error is returned 147 * via _ret_blk_ and _ret_count_ if they are non-NULL pointers. 148 * Returns 0 on success, and an error code on an error. 149 * 150 * As a special case, if the first argument is NULL, then it will 151 * attempt to free the static zeroizing buffer. (This is to keep 152 * programs that check for memory leaks happy.) 153 */ 154#define STRIDE_LENGTH 8 155errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, 156 blk64_t *ret_blk, int *ret_count) 157{ 158 int j, count; 159 static char *buf; 160 errcode_t retval; 161 162 /* If fs is null, clean up the static buffer and return */ 163 if (!fs) { 164 if (buf) { 165 free(buf); 166 buf = 0; 167 } 168 return 0; 169 } 170 /* Allocate the zeroizing buffer if necessary */ 171 if (!buf) { 172 buf = malloc(fs->blocksize * STRIDE_LENGTH); 173 if (!buf) 174 return ENOMEM; 175 memset(buf, 0, fs->blocksize * STRIDE_LENGTH); 176 } 177 /* OK, do the write loop */ 178 j=0; 179 while (j < num) { 180 if (blk % STRIDE_LENGTH) { 181 count = STRIDE_LENGTH - (blk % STRIDE_LENGTH); 182 if (count > (num - j)) 183 count = num - j; 184 } else { 185 count = num - j; 186 if (count > STRIDE_LENGTH) 187 count = STRIDE_LENGTH; 188 } 189 retval = io_channel_write_blk64(fs->io, blk, count, buf); 190 if (retval) { 191 if (ret_count) 192 *ret_count = count; 193 if (ret_blk) 194 *ret_blk = blk; 195 return retval; 196 } 197 j += count; blk += count; 198 } 199 return 0; 200} 201 202errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num, 203 blk_t *ret_blk, int *ret_count) 204{ 205 blk64_t ret_blk2; 206 errcode_t retval; 207 208 retval = ext2fs_zero_blocks2(fs, blk, num, &ret_blk2, ret_count); 209 if (retval) 210 *ret_blk = (blk_t) ret_blk2; 211 return retval; 212} 213 214/* 215 * Helper function for creating the journal using direct I/O routines 216 */ 217struct mkjournal_struct { 218 int num_blocks; 219 int newblocks; 220 blk64_t goal; 221 blk64_t blk_to_zero; 222 int zero_count; 223 int flags; 224 char *buf; 225 errcode_t err; 226}; 227 228static int mkjournal_proc(ext2_filsys fs, 229 blk64_t *blocknr, 230 e2_blkcnt_t blockcnt, 231 blk64_t ref_block EXT2FS_ATTR((unused)), 232 int ref_offset EXT2FS_ATTR((unused)), 233 void *priv_data) 234{ 235 struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data; 236 blk64_t new_blk; 237 errcode_t retval; 238 239 if (*blocknr) { 240 es->goal = *blocknr; 241 return 0; 242 } 243 if (blockcnt && 244 (EXT2FS_B2C(fs, es->goal) == EXT2FS_B2C(fs, es->goal+1))) 245 new_blk = es->goal+1; 246 else { 247 es->goal &= ~EXT2FS_CLUSTER_MASK(fs); 248 retval = ext2fs_new_block2(fs, es->goal, 0, &new_blk); 249 if (retval) { 250 es->err = retval; 251 return BLOCK_ABORT; 252 } 253 es->newblocks++; 254 } 255 if (blockcnt >= 0) 256 es->num_blocks--; 257 258 retval = 0; 259 if (blockcnt <= 0) 260 retval = io_channel_write_blk64(fs->io, new_blk, 1, es->buf); 261 else if (!(es->flags & EXT2_MKJOURNAL_LAZYINIT)) { 262 if (es->zero_count) { 263 if ((es->blk_to_zero + es->zero_count == new_blk) && 264 (es->zero_count < 1024)) 265 es->zero_count++; 266 else { 267 retval = ext2fs_zero_blocks2(fs, 268 es->blk_to_zero, 269 es->zero_count, 270 0, 0); 271 es->zero_count = 0; 272 } 273 } 274 if (es->zero_count == 0) { 275 es->blk_to_zero = new_blk; 276 es->zero_count = 1; 277 } 278 } 279 280 if (blockcnt == 0) 281 memset(es->buf, 0, fs->blocksize); 282 283 if (retval) { 284 es->err = retval; 285 return BLOCK_ABORT; 286 } 287 *blocknr = es->goal = new_blk; 288 ext2fs_block_alloc_stats2(fs, new_blk, +1); 289 290 if (es->num_blocks == 0) 291 return (BLOCK_CHANGED | BLOCK_ABORT); 292 else 293 return BLOCK_CHANGED; 294 295} 296 297/* 298 * This function creates a journal using direct I/O routines. 299 */ 300static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino, 301 blk_t num_blocks, int flags) 302{ 303 char *buf; 304 dgrp_t group, start, end, i, log_flex; 305 errcode_t retval; 306 struct ext2_inode inode; 307 unsigned long long inode_size; 308 struct mkjournal_struct es; 309 310 if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags, 311 &buf))) 312 return retval; 313 314 if ((retval = ext2fs_read_bitmaps(fs))) 315 return retval; 316 317 if ((retval = ext2fs_read_inode(fs, journal_ino, &inode))) 318 return retval; 319 320 if (inode.i_blocks > 0) 321 return EEXIST; 322 323 es.num_blocks = num_blocks; 324 es.newblocks = 0; 325 es.buf = buf; 326 es.err = 0; 327 es.flags = flags; 328 es.zero_count = 0; 329 330 if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) { 331 inode.i_flags |= EXT4_EXTENTS_FL; 332 if ((retval = ext2fs_write_inode(fs, journal_ino, &inode))) 333 return retval; 334 } 335 336 /* 337 * Set the initial goal block to be roughly at the middle of 338 * the filesystem. Pick a group that has the largest number 339 * of free blocks. 340 */ 341 group = ext2fs_group_of_blk2(fs, (ext2fs_blocks_count(fs->super) - 342 fs->super->s_first_data_block) / 2); 343 log_flex = 1 << fs->super->s_log_groups_per_flex; 344 if (fs->super->s_log_groups_per_flex && (group > log_flex)) { 345 group = group & ~(log_flex - 1); 346 while ((group < fs->group_desc_count) && 347 ext2fs_bg_free_blocks_count(fs, group) == 0) 348 group++; 349 if (group == fs->group_desc_count) 350 group = 0; 351 start = group; 352 } else 353 start = (group > 0) ? group-1 : group; 354 end = ((group+1) < fs->group_desc_count) ? group+1 : group; 355 group = start; 356 for (i=start+1; i <= end; i++) 357 if (ext2fs_bg_free_blocks_count(fs, i) > 358 ext2fs_bg_free_blocks_count(fs, group)) 359 group = i; 360 361 es.goal = ext2fs_group_first_block2(fs, group); 362 retval = ext2fs_block_iterate3(fs, journal_ino, BLOCK_FLAG_APPEND, 363 0, mkjournal_proc, &es); 364 if (es.err) { 365 retval = es.err; 366 goto errout; 367 } 368 if (es.zero_count) { 369 retval = ext2fs_zero_blocks2(fs, es.blk_to_zero, 370 es.zero_count, 0, 0); 371 if (retval) 372 goto errout; 373 } 374 375 if ((retval = ext2fs_read_inode(fs, journal_ino, &inode))) 376 goto errout; 377 378 inode_size = (unsigned long long)fs->blocksize * num_blocks; 379 inode.i_size = inode_size & 0xFFFFFFFF; 380 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF; 381 if (ext2fs_needs_large_file_feature(inode_size)) 382 fs->super->s_feature_ro_compat |= 383 EXT2_FEATURE_RO_COMPAT_LARGE_FILE; 384 ext2fs_iblk_add_blocks(fs, &inode, es.newblocks); 385 inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0); 386 inode.i_links_count = 1; 387 inode.i_mode = LINUX_S_IFREG | 0600; 388 389 if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode))) 390 goto errout; 391 retval = 0; 392 393 memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4); 394 fs->super->s_jnl_blocks[15] = inode.i_size_high; 395 fs->super->s_jnl_blocks[16] = inode.i_size; 396 fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS; 397 ext2fs_mark_super_dirty(fs); 398 399errout: 400 ext2fs_zero_blocks2(0, 0, 0, 0, 0); 401 ext2fs_free_mem(&buf); 402 return retval; 403} 404 405/* 406 * Find a reasonable journal file size (in blocks) given the number of blocks 407 * in the filesystem. For very small filesystems, it is not reasonable to 408 * have a journal that fills more than half of the filesystem. 409 */ 410int ext2fs_default_journal_size(__u64 num_blocks) 411{ 412 if (num_blocks < 2048) 413 return -1; 414 if (num_blocks < 32768) 415 return (1024); 416 if (num_blocks < 256*1024) 417 return (4096); 418 if (num_blocks < 512*1024) 419 return (8192); 420 if (num_blocks < 1024*1024) 421 return (16384); 422 return 32768; 423} 424 425/* 426 * This function adds a journal device to a filesystem 427 */ 428errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev) 429{ 430 struct stat st; 431 errcode_t retval; 432 char buf[1024]; 433 journal_superblock_t *jsb; 434 int start; 435 __u32 i, nr_users; 436 437 /* Make sure the device exists and is a block device */ 438 if (stat(journal_dev->device_name, &st) < 0) 439 return errno; 440 441 if (!S_ISBLK(st.st_mode)) 442 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */ 443 444 /* Get the journal superblock */ 445 start = 1; 446 if (journal_dev->blocksize == 1024) 447 start++; 448 if ((retval = io_channel_read_blk64(journal_dev->io, start, -1024, 449 buf))) 450 return retval; 451 452 jsb = (journal_superblock_t *) buf; 453 if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) || 454 (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2))) 455 return EXT2_ET_NO_JOURNAL_SB; 456 457 if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize) 458 return EXT2_ET_UNEXPECTED_BLOCK_SIZE; 459 460 /* Check and see if this filesystem has already been added */ 461 nr_users = ntohl(jsb->s_nr_users); 462 for (i=0; i < nr_users; i++) { 463 if (memcmp(fs->super->s_uuid, 464 &jsb->s_users[i*16], 16) == 0) 465 break; 466 } 467 if (i >= nr_users) { 468 memcpy(&jsb->s_users[nr_users*16], 469 fs->super->s_uuid, 16); 470 jsb->s_nr_users = htonl(nr_users+1); 471 } 472 473 /* Writeback the journal superblock */ 474 if ((retval = io_channel_write_blk64(journal_dev->io, start, -1024, buf))) 475 return retval; 476 477 fs->super->s_journal_inum = 0; 478 fs->super->s_journal_dev = st.st_rdev; 479 memcpy(fs->super->s_journal_uuid, jsb->s_uuid, 480 sizeof(fs->super->s_journal_uuid)); 481 fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL; 482 ext2fs_mark_super_dirty(fs); 483 return 0; 484} 485 486/* 487 * This function adds a journal inode to a filesystem, using either 488 * POSIX routines if the filesystem is mounted, or using direct I/O 489 * functions if it is not. 490 */ 491errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t num_blocks, int flags) 492{ 493 errcode_t retval; 494 ext2_ino_t journal_ino; 495 struct stat st; 496 char jfile[1024]; 497 int mount_flags; 498 int fd = -1; 499 500 if (flags & EXT2_MKJOURNAL_NO_MNT_CHECK) 501 mount_flags = 0; 502 else if ((retval = ext2fs_check_mount_point(fs->device_name, 503 &mount_flags, 504 jfile, sizeof(jfile)-10))) 505 return retval; 506 507 if (mount_flags & EXT2_MF_MOUNTED) { 508#if HAVE_EXT2_IOCTLS 509 int f = 0; 510#endif 511 strcat(jfile, "/.journal"); 512 513 /* 514 * If .../.journal already exists, make sure any 515 * immutable or append-only flags are cleared. 516 */ 517#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP) 518 (void) chflags (jfile, 0); 519#else 520#if HAVE_EXT2_IOCTLS 521 fd = open(jfile, O_RDONLY); 522 if (fd >= 0) { 523 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f); 524 close(fd); 525 if (retval) 526 return retval; 527 } 528#endif 529#endif 530 531 /* Create the journal file */ 532 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0) 533 return errno; 534 535 /* Note that we can't do lazy journal initialization for mounted 536 * filesystems, since the zero writing is also allocating the 537 * journal blocks. We could use fallocate, but not all kernels 538 * support that, and creating a journal on a mounted ext2 539 * filesystems is extremely rare these days... Ignore it. */ 540 flags &= ~EXT2_MKJOURNAL_LAZYINIT; 541 542 if ((retval = write_journal_file(fs, jfile, num_blocks, flags))) 543 goto errout; 544 545 /* Get inode number of the journal file */ 546 if (fstat(fd, &st) < 0) { 547 retval = errno; 548 goto errout; 549 } 550 551#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP) 552 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE); 553#else 554#if HAVE_EXT2_IOCTLS 555 if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) { 556 retval = errno; 557 goto errout; 558 } 559 f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL; 560 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f); 561#endif 562#endif 563 if (retval) { 564 retval = errno; 565 goto errout; 566 } 567 568 if (close(fd) < 0) { 569 retval = errno; 570 fd = -1; 571 goto errout; 572 } 573 journal_ino = st.st_ino; 574 } else { 575 if ((mount_flags & EXT2_MF_BUSY) && 576 !(fs->flags & EXT2_FLAG_EXCLUSIVE)) { 577 retval = EBUSY; 578 goto errout; 579 } 580 journal_ino = EXT2_JOURNAL_INO; 581 if ((retval = write_journal_inode(fs, journal_ino, 582 num_blocks, flags))) 583 return retval; 584 } 585 586 fs->super->s_journal_inum = journal_ino; 587 fs->super->s_journal_dev = 0; 588 memset(fs->super->s_journal_uuid, 0, 589 sizeof(fs->super->s_journal_uuid)); 590 fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL; 591 592 ext2fs_mark_super_dirty(fs); 593 return 0; 594errout: 595 if (fd > 0) 596 close(fd); 597 return retval; 598} 599 600#ifdef DEBUG 601main(int argc, char **argv) 602{ 603 errcode_t retval; 604 char *device_name; 605 ext2_filsys fs; 606 607 if (argc < 2) { 608 fprintf(stderr, "Usage: %s filesystem\n", argv[0]); 609 exit(1); 610 } 611 device_name = argv[1]; 612 613 retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0, 614 unix_io_manager, &fs); 615 if (retval) { 616 com_err(argv[0], retval, "while opening %s", device_name); 617 exit(1); 618 } 619 620 retval = ext2fs_add_journal_inode(fs, 1024, 0); 621 if (retval) { 622 com_err(argv[0], retval, "while adding journal to %s", 623 device_name); 624 exit(1); 625 } 626 retval = ext2fs_flush(fs); 627 if (retval) { 628 printf("Warning, had trouble writing out superblocks.\n"); 629 } 630 ext2fs_close(fs); 631 exit(0); 632 633} 634#endif 635