1 /*
2 * closefs.c --- close an ext2 filesystem
3 *
4 * Copyright (C) 1993, 1994, 1995, 1996 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 #if HAVE_UNISTD_H
15 #include <unistd.h>
16 #endif
17 #include <time.h>
18 #include <string.h>
19
20 #include "ext2_fs.h"
21 #include "ext2fsP.h"
22
test_root(unsigned int a,unsigned int b)23 static int test_root(unsigned int a, unsigned int b)
24 {
25 while (1) {
26 if (a < b)
27 return 0;
28 if (a == b)
29 return 1;
30 if (a % b)
31 return 0;
32 a = a / b;
33 }
34 }
35
ext2fs_bg_has_super(ext2_filsys fs,dgrp_t group)36 int ext2fs_bg_has_super(ext2_filsys fs, dgrp_t group)
37 {
38 if (group == 0)
39 return 1;
40 if (ext2fs_has_feature_sparse_super2(fs->super)) {
41 if (group == fs->super->s_backup_bgs[0] ||
42 group == fs->super->s_backup_bgs[1])
43 return 1;
44 return 0;
45 }
46 if ((group <= 1) || !ext2fs_has_feature_sparse_super(fs->super))
47 return 1;
48 if (!(group & 1))
49 return 0;
50 if (test_root(group, 3) || (test_root(group, 5)) ||
51 test_root(group, 7))
52 return 1;
53
54 return 0;
55 }
56
57 /*
58 * ext2fs_super_and_bgd_loc2()
59 * @fs: ext2 fs pointer
60 * @group given block group
61 * @ret_super_blk: if !NULL, returns super block location
62 * @ret_old_desc_blk: if !NULL, returns location of the old block
63 * group descriptor
64 * @ret_new_desc_blk: if !NULL, returns location of meta_bg block
65 * group descriptor
66 * @ret_used_blks: if !NULL, returns number of blocks used by
67 * super block and group_descriptors.
68 *
69 * Returns errcode_t of 0
70 */
ext2fs_super_and_bgd_loc2(ext2_filsys fs,dgrp_t group,blk64_t * ret_super_blk,blk64_t * ret_old_desc_blk,blk64_t * ret_new_desc_blk,blk_t * ret_used_blks)71 errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
72 dgrp_t group,
73 blk64_t *ret_super_blk,
74 blk64_t *ret_old_desc_blk,
75 blk64_t *ret_new_desc_blk,
76 blk_t *ret_used_blks)
77 {
78 blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
79 unsigned int meta_bg, meta_bg_size;
80 blk_t numblocks = 0;
81 blk64_t old_desc_blocks;
82 int has_super;
83
84 group_block = ext2fs_group_first_block2(fs, group);
85 if (group_block == 0 && fs->blocksize == 1024)
86 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
87
88 if (ext2fs_has_feature_meta_bg(fs->super))
89 old_desc_blocks = fs->super->s_first_meta_bg;
90 else
91 old_desc_blocks =
92 fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
93
94 has_super = ext2fs_bg_has_super(fs, group);
95
96 if (has_super) {
97 super_blk = group_block;
98 numblocks++;
99 }
100 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
101 meta_bg = group / meta_bg_size;
102
103 if (!ext2fs_has_feature_meta_bg(fs->super) ||
104 (meta_bg < fs->super->s_first_meta_bg)) {
105 if (has_super) {
106 old_desc_blk = group_block + 1;
107 numblocks += old_desc_blocks;
108 }
109 } else {
110 if (((group % meta_bg_size) == 0) ||
111 ((group % meta_bg_size) == 1) ||
112 ((group % meta_bg_size) == (meta_bg_size-1))) {
113 if (has_super)
114 has_super = 1;
115 new_desc_blk = group_block + has_super;
116 numblocks++;
117 }
118 }
119
120 if (ret_super_blk)
121 *ret_super_blk = super_blk;
122 if (ret_old_desc_blk)
123 *ret_old_desc_blk = old_desc_blk;
124 if (ret_new_desc_blk)
125 *ret_new_desc_blk = new_desc_blk;
126 if (ret_used_blks)
127 *ret_used_blks = numblocks;
128
129 return 0;
130 }
131
132 /*
133 * This function returns the location of the superblock, block group
134 * descriptors for a given block group. It currently returns the
135 * number of free blocks assuming that inode table and allocation
136 * bitmaps will be in the group. This is not necessarily the case
137 * when the flex_bg feature is enabled, so callers should take care!
138 * It was only really intended for use by mke2fs, and even there it's
139 * not that useful.
140 *
141 * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
142 * capable and returns the number of blocks used by super block and
143 * group descriptors.
144 */
ext2fs_super_and_bgd_loc(ext2_filsys fs,dgrp_t group,blk_t * ret_super_blk,blk_t * ret_old_desc_blk,blk_t * ret_new_desc_blk,int * ret_meta_bg)145 int ext2fs_super_and_bgd_loc(ext2_filsys fs,
146 dgrp_t group,
147 blk_t *ret_super_blk,
148 blk_t *ret_old_desc_blk,
149 blk_t *ret_new_desc_blk,
150 int *ret_meta_bg)
151 {
152 blk64_t ret_super_blk2;
153 blk64_t ret_old_desc_blk2;
154 blk64_t ret_new_desc_blk2;
155 blk_t ret_used_blks;
156 blk_t numblocks;
157 unsigned int meta_bg_size;
158
159 ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
160 &ret_old_desc_blk2,
161 &ret_new_desc_blk2,
162 &ret_used_blks);
163
164 numblocks = ext2fs_group_blocks_count(fs, group);
165
166 if (ret_super_blk)
167 *ret_super_blk = (blk_t)ret_super_blk2;
168 if (ret_old_desc_blk)
169 *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
170 if (ret_new_desc_blk)
171 *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
172 if (ret_meta_bg) {
173 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
174 *ret_meta_bg = group / meta_bg_size;
175 }
176
177 numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
178
179 return numblocks;
180 }
181
182 /*
183 * This function forces out the primary superblock. We need to only
184 * write out those fields which we have changed, since if the
185 * filesystem is mounted, it may have changed some of the other
186 * fields.
187 *
188 * It takes as input a superblock which has already been byte swapped
189 * (if necessary).
190 *
191 */
write_primary_superblock(ext2_filsys fs,struct ext2_super_block * super)192 static errcode_t write_primary_superblock(ext2_filsys fs,
193 struct ext2_super_block *super)
194 {
195 __u16 *old_super, *new_super;
196 int check_idx, write_idx, size;
197 errcode_t retval;
198
199 if (!fs->io->manager->write_byte || !fs->orig_super) {
200 fallback:
201 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
202 retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
203 super);
204 io_channel_set_blksize(fs->io, fs->blocksize);
205 return retval;
206 }
207
208 old_super = (__u16 *) fs->orig_super;
209 new_super = (__u16 *) super;
210
211 for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
212 if (old_super[check_idx] == new_super[check_idx])
213 continue;
214 write_idx = check_idx;
215 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
216 if (old_super[check_idx] == new_super[check_idx])
217 break;
218 size = 2 * (check_idx - write_idx);
219 #if 0
220 printf("Writing %d bytes starting at %d\n",
221 size, write_idx*2);
222 #endif
223 retval = io_channel_write_byte(fs->io,
224 SUPERBLOCK_OFFSET + (2 * write_idx), size,
225 new_super + write_idx);
226 if (retval == EXT2_ET_UNIMPLEMENTED)
227 goto fallback;
228 if (retval)
229 return retval;
230 }
231 memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
232 return 0;
233 }
234
235
236 /*
237 * Updates the revision to EXT2_DYNAMIC_REV
238 */
ext2fs_update_dynamic_rev(ext2_filsys fs)239 void ext2fs_update_dynamic_rev(ext2_filsys fs)
240 {
241 struct ext2_super_block *sb = fs->super;
242
243 if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
244 return;
245
246 sb->s_rev_level = EXT2_DYNAMIC_REV;
247 sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
248 sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
249 /* s_uuid is handled by e2fsck already */
250 /* other fields should be left alone */
251 }
252
write_backup_super(ext2_filsys fs,dgrp_t group,blk64_t group_block,struct ext2_super_block * super_shadow)253 static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
254 blk64_t group_block,
255 struct ext2_super_block *super_shadow)
256 {
257 errcode_t retval;
258 dgrp_t sgrp = group;
259
260 if (sgrp > ((1 << 16) - 1))
261 sgrp = (1 << 16) - 1;
262
263 super_shadow->s_block_group_nr = ext2fs_cpu_to_le16(sgrp);
264
265 retval = ext2fs_superblock_csum_set(fs, super_shadow);
266 if (retval)
267 return retval;
268
269 return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
270 super_shadow);
271 }
272
ext2fs_flush(ext2_filsys fs)273 errcode_t ext2fs_flush(ext2_filsys fs)
274 {
275 return ext2fs_flush2(fs, 0);
276 }
277
ext2fs_flush2(ext2_filsys fs,int flags)278 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
279 {
280 dgrp_t i;
281 errcode_t retval;
282 unsigned long fs_state;
283 __u32 feature_incompat;
284 struct ext2_super_block *super_shadow = 0;
285 struct opaque_ext2_group_desc *group_shadow = 0;
286 #ifdef WORDS_BIGENDIAN
287 struct ext2_group_desc *gdp;
288 dgrp_t j;
289 #endif
290 char *group_ptr;
291 blk64_t old_desc_blocks;
292 struct ext2fs_numeric_progress_struct progress;
293
294 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
295
296 if ((fs->flags & EXT2_FLAG_SUPER_ONLY) == 0 &&
297 !ext2fs_has_feature_journal_dev(fs->super) &&
298 fs->group_desc == NULL)
299 return EXT2_ET_NO_GDESC;
300
301 fs_state = fs->super->s_state;
302 feature_incompat = fs->super->s_feature_incompat;
303
304 fs->super->s_wtime = fs->now ? fs->now : time(NULL);
305 fs->super->s_block_group_nr = 0;
306
307 /*
308 * If the write_bitmaps() function is present, call it to
309 * flush the bitmaps. This is done this way so that a simple
310 * program that doesn't mess with the bitmaps doesn't need to
311 * drag in the bitmaps.c code.
312 *
313 * Bitmap checksums live in the group descriptor, so the
314 * bitmaps need to be written before the descriptors.
315 */
316 if (fs->write_bitmaps) {
317 retval = fs->write_bitmaps(fs);
318 if (retval)
319 goto errout;
320 }
321
322 /*
323 * Set the state of the FS to be non-valid. (The state has
324 * already been backed up earlier, and will be restored after
325 * we write out the backup superblocks.)
326 */
327 fs->super->s_state &= ~EXT2_VALID_FS;
328 ext2fs_clear_feature_journal_needs_recovery(fs->super);
329
330 /* Byte swap the superblock and the group descriptors if necessary */
331 #ifdef WORDS_BIGENDIAN
332 retval = EXT2_ET_NO_MEMORY;
333 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
334 if (retval)
335 goto errout;
336 memcpy(super_shadow, fs->super, sizeof(struct ext2_super_block));
337 ext2fs_swap_super(super_shadow);
338
339 if (((fs->flags & EXT2_FLAG_SUPER_ONLY) == 0) &&
340 !ext2fs_has_feature_journal_dev(fs->super)) {
341 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
342 &group_shadow);
343 if (retval)
344 goto errout;
345 memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
346 fs->desc_blocks);
347
348 for (j = 0; j < fs->group_desc_count; j++) {
349 gdp = ext2fs_group_desc(fs, group_shadow, j);
350 ext2fs_swap_group_desc2(fs, gdp);
351 }
352 }
353 #else
354 super_shadow = fs->super;
355 group_shadow = fs->group_desc;
356 #endif
357
358 /*
359 * If this is an external journal device, don't write out the
360 * block group descriptors or any of the backup superblocks
361 */
362 if (ext2fs_has_feature_journal_dev(fs->super))
363 goto write_primary_superblock_only;
364
365 /*
366 * Write out the master group descriptors, and the backup
367 * superblocks and group descriptors.
368 */
369 group_ptr = (char *) group_shadow;
370 if (ext2fs_has_feature_meta_bg(fs->super)) {
371 old_desc_blocks = fs->super->s_first_meta_bg;
372 if (old_desc_blocks > fs->desc_blocks)
373 old_desc_blocks = fs->desc_blocks;
374 } else
375 old_desc_blocks = fs->desc_blocks;
376
377 if (fs->progress_ops && fs->progress_ops->init)
378 (fs->progress_ops->init)(fs, &progress, NULL,
379 fs->group_desc_count);
380
381
382 for (i = 0; i < fs->group_desc_count; i++) {
383 blk64_t super_blk, old_desc_blk, new_desc_blk;
384
385 if (fs->progress_ops && fs->progress_ops->update)
386 (fs->progress_ops->update)(fs, &progress, i);
387 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
388 &new_desc_blk, 0);
389
390 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
391 retval = write_backup_super(fs, i, super_blk,
392 super_shadow);
393 if (retval)
394 goto errout;
395 }
396 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
397 continue;
398 if ((old_desc_blk) &&
399 (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
400 retval = io_channel_write_blk64(fs->io,
401 old_desc_blk, old_desc_blocks, group_ptr);
402 if (retval)
403 goto errout;
404 }
405 if (new_desc_blk) {
406 int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
407
408 retval = io_channel_write_blk64(fs->io, new_desc_blk,
409 1, group_ptr + (meta_bg*fs->blocksize));
410 if (retval)
411 goto errout;
412 }
413 }
414
415 if (fs->progress_ops && fs->progress_ops->close)
416 (fs->progress_ops->close)(fs, &progress, NULL);
417
418 write_primary_superblock_only:
419 /*
420 * Write out master superblock. This has to be done
421 * separately, since it is located at a fixed location
422 * (SUPERBLOCK_OFFSET). We flush all other pending changes
423 * out to disk first, just to avoid a race condition with an
424 * insy-tinsy window....
425 */
426
427 fs->super->s_block_group_nr = 0;
428 fs->super->s_state = fs_state;
429 fs->super->s_feature_incompat = feature_incompat;
430 #ifdef WORDS_BIGENDIAN
431 *super_shadow = *fs->super;
432 ext2fs_swap_super(super_shadow);
433 #endif
434
435 retval = ext2fs_superblock_csum_set(fs, super_shadow);
436 if (retval)
437 return retval;
438
439 if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC)) {
440 retval = io_channel_flush(fs->io);
441 if (retval)
442 goto errout;
443 }
444 retval = write_primary_superblock(fs, super_shadow);
445 if (retval)
446 goto errout;
447
448 fs->flags &= ~EXT2_FLAG_DIRTY;
449
450 if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC)) {
451 retval = io_channel_flush(fs->io);
452 if (retval)
453 goto errout;
454 }
455 errout:
456 fs->super->s_state = fs_state;
457 #ifdef WORDS_BIGENDIAN
458 if (super_shadow)
459 ext2fs_free_mem(&super_shadow);
460 if (group_shadow)
461 ext2fs_free_mem(&group_shadow);
462 #endif
463 return retval;
464 }
465
ext2fs_close_free(ext2_filsys * fs_ptr)466 errcode_t ext2fs_close_free(ext2_filsys *fs_ptr)
467 {
468 errcode_t ret;
469 ext2_filsys fs = *fs_ptr;
470
471 ret = ext2fs_close2(fs, 0);
472 if (ret)
473 ext2fs_free(fs);
474 *fs_ptr = NULL;
475 return ret;
476 }
477
ext2fs_close(ext2_filsys fs)478 errcode_t ext2fs_close(ext2_filsys fs)
479 {
480 return ext2fs_close2(fs, 0);
481 }
482
ext2fs_close2(ext2_filsys fs,int flags)483 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
484 {
485 errcode_t retval;
486 int meta_blks;
487 io_stats stats = 0;
488
489 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
490
491 if (fs->write_bitmaps) {
492 retval = fs->write_bitmaps(fs);
493 if (retval)
494 return retval;
495 }
496 if (fs->super->s_kbytes_written &&
497 fs->io->manager->get_stats)
498 fs->io->manager->get_stats(fs->io, &stats);
499 if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
500 fs->super->s_kbytes_written += stats->bytes_written >> 10;
501 meta_blks = fs->desc_blocks + 1;
502 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
503 fs->super->s_kbytes_written += meta_blks /
504 (fs->blocksize / 1024);
505 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
506 fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
507 }
508 if (fs->flags & EXT2_FLAG_DIRTY) {
509 retval = ext2fs_flush2(fs, flags);
510 if (retval)
511 return retval;
512 }
513
514 retval = ext2fs_mmp_stop(fs);
515 if (retval)
516 return retval;
517
518 ext2fs_free(fs);
519 return 0;
520 }
521
522