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 */
ext2fs_create_journal_superblock(ext2_filsys fs,__u32 size,int flags,char ** ret_jsb)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 */
write_journal_file(ext2_filsys fs,char * filename,blk_t size,int flags)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
ext2fs_zero_blocks(ext2_filsys fs,blk_t blk,int num,blk_t * ret_blk,int * ret_count)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
mkjournal_proc(ext2_filsys fs,blk_t * blocknr,e2_blkcnt_t blockcnt,blk_t ref_block EXT2FS_ATTR ((unused)),int ref_offset EXT2FS_ATTR ((unused)),void * priv_data)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 */
write_journal_inode(ext2_filsys fs,ext2_ino_t journal_ino,blk_t size,int flags)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 */
ext2fs_default_journal_size(__u64 blocks)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 */
ext2fs_add_journal_device(ext2_filsys fs,ext2_filsys journal_dev)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 */
ext2fs_add_journal_inode(ext2_filsys fs,blk_t size,int flags)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
main(int argc,char ** argv)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
586