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
40 #include "kernel-jbd.h"
41
42 /*
43 * This function automatically sets up the journal superblock and
44 * returns it as an allocated block.
45 */
ext2fs_create_journal_superblock(ext2_filsys fs,__u32 num_blocks,int flags,char ** ret_jsb)46 errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
47 __u32 num_blocks, int flags,
48 char **ret_jsb)
49 {
50 errcode_t retval;
51 journal_superblock_t *jsb;
52
53 if (num_blocks < JFS_MIN_JOURNAL_BLOCKS)
54 return EXT2_ET_JOURNAL_TOO_SMALL;
55
56 if ((retval = ext2fs_get_mem(fs->blocksize, &jsb)))
57 return retval;
58
59 memset (jsb, 0, fs->blocksize);
60
61 jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
62 if (flags & EXT2_MKJOURNAL_V1_SUPER)
63 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
64 else
65 jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
66 jsb->s_blocksize = htonl(fs->blocksize);
67 jsb->s_maxlen = htonl(num_blocks);
68 jsb->s_nr_users = htonl(1);
69 jsb->s_first = htonl(1);
70 jsb->s_sequence = htonl(1);
71 memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
72 /*
73 * If we're creating an external journal device, we need to
74 * adjust these fields.
75 */
76 if (ext2fs_has_feature_journal_dev(fs->super)) {
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 */
write_journal_file(ext2_filsys fs,char * filename,blk_t num_blocks,int flags)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)
ext2fs_zero_blocks2(ext2_filsys fs,blk64_t blk,int num,blk64_t * ret_blk,int * ret_count)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 stride_length = 0;
166 }
167 return 0;
168 }
169
170 /* Deal with zeroing less than 1 block */
171 if (num <= 0)
172 return 0;
173
174 /* Try a zero out command, if supported */
175 retval = io_channel_zeroout(fs->io, blk, num);
176 if (retval == 0)
177 return 0;
178
179 /* Allocate the zeroizing buffer if necessary */
180 if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) {
181 void *p;
182 int new_stride = num;
183
184 if (new_stride > MAX_STRIDE_LENGTH)
185 new_stride = MAX_STRIDE_LENGTH;
186 p = realloc(buf, fs->blocksize * new_stride);
187 if (!p)
188 return EXT2_ET_NO_MEMORY;
189 buf = p;
190 stride_length = new_stride;
191 memset(buf, 0, fs->blocksize * stride_length);
192 }
193 /* OK, do the write loop */
194 j=0;
195 while (j < num) {
196 if (blk % stride_length) {
197 count = stride_length - (blk % stride_length);
198 if (count > (num - j))
199 count = num - j;
200 } else {
201 count = num - j;
202 if (count > stride_length)
203 count = stride_length;
204 }
205 retval = io_channel_write_blk64(fs->io, blk, count, buf);
206 if (retval) {
207 if (ret_count)
208 *ret_count = count;
209 if (ret_blk)
210 *ret_blk = blk;
211 return retval;
212 }
213 j += count; blk += count;
214 }
215 return 0;
216 }
217
ext2fs_zero_blocks(ext2_filsys fs,blk_t blk,int num,blk_t * ret_blk,int * ret_count)218 errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num,
219 blk_t *ret_blk, int *ret_count)
220 {
221 blk64_t ret_blk2;
222 errcode_t retval;
223
224 retval = ext2fs_zero_blocks2(fs, blk, num, &ret_blk2, ret_count);
225 if (retval)
226 *ret_blk = (blk_t) ret_blk2;
227 return retval;
228 }
229
230 /*
231 * Calculate the initial goal block to be roughly at the middle of the
232 * filesystem. Pick a group that has the largest number of free
233 * blocks.
234 */
get_midpoint_journal_block(ext2_filsys fs)235 static blk64_t get_midpoint_journal_block(ext2_filsys fs)
236 {
237 dgrp_t group, start, end, i, log_flex;
238
239 group = ext2fs_group_of_blk2(fs, (ext2fs_blocks_count(fs->super) -
240 fs->super->s_first_data_block) / 2);
241 log_flex = 1 << fs->super->s_log_groups_per_flex;
242 if (fs->super->s_log_groups_per_flex && (group > log_flex)) {
243 group = group & ~(log_flex - 1);
244 while ((group < fs->group_desc_count) &&
245 ext2fs_bg_free_blocks_count(fs, group) == 0)
246 group++;
247 if (group == fs->group_desc_count)
248 group = 0;
249 start = group;
250 } else
251 start = (group > 0) ? group-1 : group;
252 end = ((group+1) < fs->group_desc_count) ? group+1 : group;
253 group = start;
254 for (i = start + 1; i <= end; i++)
255 if (ext2fs_bg_free_blocks_count(fs, i) >
256 ext2fs_bg_free_blocks_count(fs, group))
257 group = i;
258 return ext2fs_group_first_block2(fs, group);
259 }
260
261 /*
262 * This function creates a journal using direct I/O routines.
263 */
write_journal_inode(ext2_filsys fs,ext2_ino_t journal_ino,blk_t num_blocks,blk64_t goal,int flags)264 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
265 blk_t num_blocks, blk64_t goal, int flags)
266 {
267 char *buf;
268 errcode_t retval;
269 struct ext2_inode inode;
270 unsigned long long inode_size;
271 int falloc_flags = EXT2_FALLOCATE_FORCE_INIT;
272 blk64_t zblk;
273
274 if ((retval = ext2fs_create_journal_superblock(fs, num_blocks, flags,
275 &buf)))
276 return retval;
277
278 if ((retval = ext2fs_read_bitmaps(fs)))
279 goto out2;
280
281 if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
282 goto out2;
283
284 if (inode.i_blocks > 0) {
285 retval = EEXIST;
286 goto out2;
287 }
288
289 if (goal == ~0ULL)
290 goal = get_midpoint_journal_block(fs);
291
292 if (ext2fs_has_feature_extents(fs->super))
293 inode.i_flags |= EXT4_EXTENTS_FL;
294
295 if (!(flags & EXT2_MKJOURNAL_LAZYINIT))
296 falloc_flags |= EXT2_FALLOCATE_ZERO_BLOCKS;
297
298 inode_size = (unsigned long long)fs->blocksize * num_blocks;
299 inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
300 inode.i_links_count = 1;
301 inode.i_mode = LINUX_S_IFREG | 0600;
302 retval = ext2fs_inode_size_set(fs, &inode, inode_size);
303 if (retval)
304 goto out2;
305
306 retval = ext2fs_fallocate(fs, falloc_flags, journal_ino,
307 &inode, goal, 0, num_blocks);
308 if (retval)
309 goto out2;
310
311 if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode)))
312 goto out2;
313
314 retval = ext2fs_bmap2(fs, journal_ino, &inode, NULL, 0, 0, NULL, &zblk);
315 if (retval)
316 goto out2;
317
318 retval = io_channel_write_blk64(fs->io, zblk, 1, buf);
319 if (retval)
320 goto out2;
321
322 memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
323 fs->super->s_jnl_blocks[15] = inode.i_size_high;
324 fs->super->s_jnl_blocks[16] = inode.i_size;
325 fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
326 ext2fs_mark_super_dirty(fs);
327
328 out2:
329 ext2fs_free_mem(&buf);
330 return retval;
331 }
332
333 /*
334 * Find a reasonable journal file size (in blocks) given the number of blocks
335 * in the filesystem. For very small filesystems, it is not reasonable to
336 * have a journal that fills more than half of the filesystem.
337 *
338 * n.b. comments assume 4k blocks
339 */
ext2fs_default_journal_size(__u64 num_blocks)340 int ext2fs_default_journal_size(__u64 num_blocks)
341 {
342 if (num_blocks < 2048)
343 return -1;
344 if (num_blocks < 32768) /* 128 MB */
345 return (1024); /* 4 MB */
346 if (num_blocks < 256*1024) /* 1 GB */
347 return (4096); /* 16 MB */
348 if (num_blocks < 512*1024) /* 2 GB */
349 return (8192); /* 32 MB */
350 if (num_blocks < 4096*1024) /* 16 GB */
351 return (16384); /* 64 MB */
352 if (num_blocks < 8192*1024) /* 32 GB */
353 return (32768); /* 128 MB */
354 if (num_blocks < 16384*1024) /* 64 GB */
355 return (65536); /* 256 MB */
356 if (num_blocks < 32768*1024) /* 128 GB */
357 return (131072); /* 512 MB */
358 return 262144; /* 1 GB */
359 }
360
ext2fs_journal_sb_start(int blocksize)361 int ext2fs_journal_sb_start(int blocksize)
362 {
363 if (blocksize == EXT2_MIN_BLOCK_SIZE)
364 return 2;
365 return 1;
366 }
367
368 /*
369 * This function adds a journal device to a filesystem
370 */
ext2fs_add_journal_device(ext2_filsys fs,ext2_filsys journal_dev)371 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
372 {
373 struct stat st;
374 errcode_t retval;
375 char buf[SUPERBLOCK_SIZE];
376 journal_superblock_t *jsb;
377 int start;
378 __u32 i, nr_users;
379
380 /* Make sure the device exists and is a block device */
381 if (stat(journal_dev->device_name, &st) < 0)
382 return errno;
383
384 if (!S_ISBLK(st.st_mode))
385 return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
386
387 /* Get the journal superblock */
388 start = ext2fs_journal_sb_start(journal_dev->blocksize);
389 if ((retval = io_channel_read_blk64(journal_dev->io, start,
390 -SUPERBLOCK_SIZE,
391 buf)))
392 return retval;
393
394 jsb = (journal_superblock_t *) buf;
395 if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
396 (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
397 return EXT2_ET_NO_JOURNAL_SB;
398
399 if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
400 return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
401
402 /* Check and see if this filesystem has already been added */
403 nr_users = ntohl(jsb->s_nr_users);
404 if (nr_users > JFS_USERS_MAX)
405 return EXT2_ET_CORRUPT_JOURNAL_SB;
406 for (i=0; i < nr_users; i++) {
407 if (memcmp(fs->super->s_uuid,
408 &jsb->s_users[i*16], 16) == 0)
409 break;
410 }
411 if (i >= nr_users) {
412 memcpy(&jsb->s_users[nr_users*16],
413 fs->super->s_uuid, 16);
414 jsb->s_nr_users = htonl(nr_users+1);
415 }
416
417 /* Writeback the journal superblock */
418 if ((retval = io_channel_write_blk64(journal_dev->io, start,
419 -SUPERBLOCK_SIZE, buf)))
420 return retval;
421
422 fs->super->s_journal_inum = 0;
423 fs->super->s_journal_dev = st.st_rdev;
424 memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
425 sizeof(fs->super->s_journal_uuid));
426 memset(fs->super->s_jnl_blocks, 0, sizeof(fs->super->s_jnl_blocks));
427 ext2fs_set_feature_journal(fs->super);
428 ext2fs_mark_super_dirty(fs);
429 return 0;
430 }
431
432 /*
433 * This function adds a journal inode to a filesystem, using either
434 * POSIX routines if the filesystem is mounted, or using direct I/O
435 * functions if it is not.
436 */
ext2fs_add_journal_inode2(ext2_filsys fs,blk_t num_blocks,blk64_t goal,int flags)437 errcode_t ext2fs_add_journal_inode2(ext2_filsys fs, blk_t num_blocks,
438 blk64_t goal, int flags)
439 {
440 errcode_t retval;
441 ext2_ino_t journal_ino;
442 struct stat st;
443 char jfile[1024];
444 int mount_flags;
445 int fd = -1;
446
447 if (flags & EXT2_MKJOURNAL_NO_MNT_CHECK)
448 mount_flags = 0;
449 else if ((retval = ext2fs_check_mount_point(fs->device_name,
450 &mount_flags,
451 jfile, sizeof(jfile)-10)))
452 return retval;
453
454 if (mount_flags & EXT2_MF_MOUNTED) {
455 #if HAVE_EXT2_IOCTLS
456 int f = 0;
457 #endif
458 strcat(jfile, "/.journal");
459
460 /*
461 * If .../.journal already exists, make sure any
462 * immutable or append-only flags are cleared.
463 */
464 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
465 (void) chflags (jfile, 0);
466 #else
467 #if HAVE_EXT2_IOCTLS
468 fd = open(jfile, O_RDONLY);
469 if (fd >= 0) {
470 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
471 close(fd);
472 if (retval)
473 return retval;
474 }
475 #endif
476 #endif
477
478 /* Create the journal file */
479 if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
480 return errno;
481
482 /* Note that we can't do lazy journal initialization for mounted
483 * filesystems, since the zero writing is also allocating the
484 * journal blocks. We could use fallocate, but not all kernels
485 * support that, and creating a journal on a mounted ext2
486 * filesystems is extremely rare these days... Ignore it. */
487 flags &= ~EXT2_MKJOURNAL_LAZYINIT;
488
489 if ((retval = write_journal_file(fs, jfile, num_blocks, flags)))
490 goto errout;
491
492 /* Get inode number of the journal file */
493 if (fstat(fd, &st) < 0) {
494 retval = errno;
495 goto errout;
496 }
497
498 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
499 retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
500 #else
501 #if HAVE_EXT2_IOCTLS
502 if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) {
503 retval = errno;
504 goto errout;
505 }
506 f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
507 retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
508 #endif
509 #endif
510 if (retval) {
511 retval = errno;
512 goto errout;
513 }
514
515 if (close(fd) < 0) {
516 retval = errno;
517 fd = -1;
518 goto errout;
519 }
520 journal_ino = st.st_ino;
521 memset(fs->super->s_jnl_blocks, 0,
522 sizeof(fs->super->s_jnl_blocks));
523 } else {
524 if ((mount_flags & EXT2_MF_BUSY) &&
525 !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
526 retval = EBUSY;
527 goto errout;
528 }
529 journal_ino = EXT2_JOURNAL_INO;
530 if ((retval = write_journal_inode(fs, journal_ino,
531 num_blocks, goal, flags)))
532 return retval;
533 }
534
535 fs->super->s_journal_inum = journal_ino;
536 fs->super->s_journal_dev = 0;
537 memset(fs->super->s_journal_uuid, 0,
538 sizeof(fs->super->s_journal_uuid));
539 ext2fs_set_feature_journal(fs->super);
540
541 ext2fs_mark_super_dirty(fs);
542 return 0;
543 errout:
544 if (fd >= 0)
545 close(fd);
546 return retval;
547 }
548
ext2fs_add_journal_inode(ext2_filsys fs,blk_t num_blocks,int flags)549 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t num_blocks, int flags)
550 {
551 return ext2fs_add_journal_inode2(fs, num_blocks, ~0ULL, flags);
552 }
553
554
555 #ifdef DEBUG
main(int argc,char ** argv)556 main(int argc, char **argv)
557 {
558 errcode_t retval;
559 char *device_name;
560 ext2_filsys fs;
561
562 if (argc < 2) {
563 fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
564 exit(1);
565 }
566 device_name = argv[1];
567
568 retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
569 unix_io_manager, &fs);
570 if (retval) {
571 com_err(argv[0], retval, "while opening %s", device_name);
572 exit(1);
573 }
574
575 retval = ext2fs_add_journal_inode(fs, JFS_MIN_JOURNAL_BLOCKS, 0);
576 if (retval) {
577 com_err(argv[0], retval, "while adding journal to %s",
578 device_name);
579 exit(1);
580 }
581 retval = ext2fs_flush(fs);
582 if (retval) {
583 printf("Warning, had trouble writing out superblocks.\n");
584 }
585 ext2fs_close_free(&fs);
586 exit(0);
587
588 }
589 #endif
590