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 <stdio.h>
13 #if HAVE_UNISTD_H
14 #include <unistd.h>
15 #endif
16 #include <time.h>
17 #include <string.h>
18
19 #include "ext2_fs.h"
20 #include "ext2fsP.h"
21
test_root(unsigned int a,unsigned int b)22 static int test_root(unsigned int a, unsigned int b)
23 {
24 while (1) {
25 if (a < b)
26 return 0;
27 if (a == b)
28 return 1;
29 if (a % b)
30 return 0;
31 a = a / b;
32 }
33 }
34
ext2fs_bg_has_super(ext2_filsys fs,dgrp_t group)35 int ext2fs_bg_has_super(ext2_filsys fs, dgrp_t group)
36 {
37 if (!(fs->super->s_feature_ro_compat &
38 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER) || group <= 1)
39 return 1;
40 if (!(group & 1))
41 return 0;
42 if (test_root(group, 3) || (test_root(group, 5)) ||
43 test_root(group, 7))
44 return 1;
45
46 return 0;
47 }
48
49 /*
50 * ext2fs_super_and_bgd_loc2()
51 * @fs: ext2 fs pointer
52 * @group given block group
53 * @ret_super_blk: if !NULL, returns super block location
54 * @ret_old_desc_blk: if !NULL, returns location of the old block
55 * group descriptor
56 * @ret_new_desc_blk: if !NULL, returns location of meta_bg block
57 * group descriptor
58 * @ret_used_blks: if !NULL, returns number of blocks used by
59 * super block and group_descriptors.
60 *
61 * Returns errcode_t of 0
62 */
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)63 errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
64 dgrp_t group,
65 blk64_t *ret_super_blk,
66 blk64_t *ret_old_desc_blk,
67 blk64_t *ret_new_desc_blk,
68 blk_t *ret_used_blks)
69 {
70 blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
71 unsigned int meta_bg, meta_bg_size;
72 blk_t numblocks = 0;
73 blk64_t old_desc_blocks;
74 int has_super;
75
76 group_block = ext2fs_group_first_block2(fs, group);
77 if (group_block == 0 && fs->blocksize == 1024)
78 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
79
80 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
81 old_desc_blocks = fs->super->s_first_meta_bg;
82 else
83 old_desc_blocks =
84 fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
85
86 has_super = ext2fs_bg_has_super(fs, group);
87
88 if (has_super) {
89 super_blk = group_block;
90 numblocks++;
91 }
92 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
93 meta_bg = group / meta_bg_size;
94
95 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
96 (meta_bg < fs->super->s_first_meta_bg)) {
97 if (has_super) {
98 old_desc_blk = group_block + 1;
99 numblocks += old_desc_blocks;
100 }
101 } else {
102 if (((group % meta_bg_size) == 0) ||
103 ((group % meta_bg_size) == 1) ||
104 ((group % meta_bg_size) == (meta_bg_size-1))) {
105 if (has_super)
106 has_super = 1;
107 new_desc_blk = group_block + has_super;
108 numblocks++;
109 }
110 }
111
112 if (ret_super_blk)
113 *ret_super_blk = super_blk;
114 if (ret_old_desc_blk)
115 *ret_old_desc_blk = old_desc_blk;
116 if (ret_new_desc_blk)
117 *ret_new_desc_blk = new_desc_blk;
118 if (ret_used_blks)
119 *ret_used_blks = numblocks;
120
121 return 0;
122 }
123
124 /*
125 * This function returns the location of the superblock, block group
126 * descriptors for a given block group. It currently returns the
127 * number of free blocks assuming that inode table and allocation
128 * bitmaps will be in the group. This is not necessarily the case
129 * when the flex_bg feature is enabled, so callers should take care!
130 * It was only really intended for use by mke2fs, and even there it's
131 * not that useful.
132 *
133 * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
134 * capable and returns the number of blocks used by super block and
135 * group descriptors.
136 */
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)137 int ext2fs_super_and_bgd_loc(ext2_filsys fs,
138 dgrp_t group,
139 blk_t *ret_super_blk,
140 blk_t *ret_old_desc_blk,
141 blk_t *ret_new_desc_blk,
142 int *ret_meta_bg)
143 {
144 blk64_t ret_super_blk2;
145 blk64_t ret_old_desc_blk2;
146 blk64_t ret_new_desc_blk2;
147 blk_t ret_used_blks;
148 blk_t numblocks;
149 unsigned int meta_bg_size;
150
151 ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
152 &ret_old_desc_blk2,
153 &ret_new_desc_blk2,
154 &ret_used_blks);
155
156 numblocks = ext2fs_group_blocks_count(fs, group);
157
158 if (ret_super_blk)
159 *ret_super_blk = (blk_t)ret_super_blk2;
160 if (ret_old_desc_blk)
161 *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
162 if (ret_new_desc_blk)
163 *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
164 if (ret_meta_bg) {
165 meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
166 *ret_meta_bg = group / meta_bg_size;
167 }
168
169 numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
170
171 return numblocks;
172 }
173
174 /*
175 * This function forces out the primary superblock. We need to only
176 * write out those fields which we have changed, since if the
177 * filesystem is mounted, it may have changed some of the other
178 * fields.
179 *
180 * It takes as input a superblock which has already been byte swapped
181 * (if necessary).
182 *
183 */
write_primary_superblock(ext2_filsys fs,struct ext2_super_block * super)184 static errcode_t write_primary_superblock(ext2_filsys fs,
185 struct ext2_super_block *super)
186 {
187 __u16 *old_super, *new_super;
188 int check_idx, write_idx, size;
189 errcode_t retval;
190
191 if (!fs->io->manager->write_byte || !fs->orig_super) {
192 fallback:
193 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
194 retval = io_channel_write_blk64(fs->io, 1, -SUPERBLOCK_SIZE,
195 super);
196 io_channel_set_blksize(fs->io, fs->blocksize);
197 return retval;
198 }
199
200 old_super = (__u16 *) fs->orig_super;
201 new_super = (__u16 *) super;
202
203 for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
204 if (old_super[check_idx] == new_super[check_idx])
205 continue;
206 write_idx = check_idx;
207 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
208 if (old_super[check_idx] == new_super[check_idx])
209 break;
210 size = 2 * (check_idx - write_idx);
211 #if 0
212 printf("Writing %d bytes starting at %d\n",
213 size, write_idx*2);
214 #endif
215 retval = io_channel_write_byte(fs->io,
216 SUPERBLOCK_OFFSET + (2 * write_idx), size,
217 new_super + write_idx);
218 if (retval == EXT2_ET_UNIMPLEMENTED)
219 goto fallback;
220 if (retval)
221 return retval;
222 }
223 memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
224 return 0;
225 }
226
227
228 /*
229 * Updates the revision to EXT2_DYNAMIC_REV
230 */
ext2fs_update_dynamic_rev(ext2_filsys fs)231 void ext2fs_update_dynamic_rev(ext2_filsys fs)
232 {
233 struct ext2_super_block *sb = fs->super;
234
235 if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
236 return;
237
238 sb->s_rev_level = EXT2_DYNAMIC_REV;
239 sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
240 sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
241 /* s_uuid is handled by e2fsck already */
242 /* other fields should be left alone */
243 }
244
write_backup_super(ext2_filsys fs,dgrp_t group,blk64_t group_block,struct ext2_super_block * super_shadow)245 static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
246 blk64_t group_block,
247 struct ext2_super_block *super_shadow)
248 {
249 dgrp_t sgrp = group;
250
251 if (sgrp > ((1 << 16) - 1))
252 sgrp = (1 << 16) - 1;
253 #ifdef WORDS_BIGENDIAN
254 super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);
255 #else
256 fs->super->s_block_group_nr = sgrp;
257 #endif
258
259 return io_channel_write_blk64(fs->io, group_block, -SUPERBLOCK_SIZE,
260 super_shadow);
261 }
262
ext2fs_flush(ext2_filsys fs)263 errcode_t ext2fs_flush(ext2_filsys fs)
264 {
265 return ext2fs_flush2(fs, 0);
266 }
267
ext2fs_flush2(ext2_filsys fs,int flags)268 errcode_t ext2fs_flush2(ext2_filsys fs, int flags)
269 {
270 dgrp_t i;
271 errcode_t retval;
272 unsigned long fs_state;
273 __u32 feature_incompat;
274 struct ext2_super_block *super_shadow = 0;
275 struct ext2_group_desc *group_shadow = 0;
276 #ifdef WORDS_BIGENDIAN
277 struct ext2_group_desc *gdp;
278 dgrp_t j;
279 #endif
280 char *group_ptr;
281 int old_desc_blocks;
282 struct ext2fs_numeric_progress_struct progress;
283
284 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
285
286 fs_state = fs->super->s_state;
287 feature_incompat = fs->super->s_feature_incompat;
288
289 fs->super->s_wtime = fs->now ? fs->now : time(NULL);
290 fs->super->s_block_group_nr = 0;
291 #ifdef WORDS_BIGENDIAN
292 retval = EXT2_ET_NO_MEMORY;
293 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
294 if (retval)
295 goto errout;
296 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
297 &group_shadow);
298 if (retval)
299 goto errout;
300 memcpy(group_shadow, fs->group_desc, (size_t) fs->blocksize *
301 fs->desc_blocks);
302
303 /* swap the group descriptors */
304 for (j = 0; j < fs->group_desc_count; j++) {
305 gdp = ext2fs_group_desc(fs, group_shadow, j);
306 ext2fs_swap_group_desc2(fs, gdp);
307 }
308 #else
309 super_shadow = fs->super;
310 group_shadow = ext2fs_group_desc(fs, fs->group_desc, 0);
311 #endif
312
313 /*
314 * Set the state of the FS to be non-valid. (The state has
315 * already been backed up earlier, and will be restored after
316 * we write out the backup superblocks.)
317 */
318 fs->super->s_state &= ~EXT2_VALID_FS;
319 fs->super->s_feature_incompat &= ~EXT3_FEATURE_INCOMPAT_RECOVER;
320 #ifdef WORDS_BIGENDIAN
321 *super_shadow = *fs->super;
322 ext2fs_swap_super(super_shadow);
323 #endif
324
325 /*
326 * If this is an external journal device, don't write out the
327 * block group descriptors or any of the backup superblocks
328 */
329 if (fs->super->s_feature_incompat &
330 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
331 goto write_primary_superblock_only;
332
333 /*
334 * Write out the master group descriptors, and the backup
335 * superblocks and group descriptors.
336 */
337 group_ptr = (char *) group_shadow;
338 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
339 old_desc_blocks = fs->super->s_first_meta_bg;
340 else
341 old_desc_blocks = fs->desc_blocks;
342
343 ext2fs_numeric_progress_init(fs, &progress, NULL,
344 fs->group_desc_count);
345
346
347 for (i = 0; i < fs->group_desc_count; i++) {
348 blk64_t super_blk, old_desc_blk, new_desc_blk;
349
350 ext2fs_numeric_progress_update(fs, &progress, i);
351 ext2fs_super_and_bgd_loc2(fs, i, &super_blk, &old_desc_blk,
352 &new_desc_blk, 0);
353
354 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
355 retval = write_backup_super(fs, i, super_blk,
356 super_shadow);
357 if (retval)
358 goto errout;
359 }
360 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
361 continue;
362 if ((old_desc_blk) &&
363 (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
364 retval = io_channel_write_blk64(fs->io,
365 old_desc_blk, old_desc_blocks, group_ptr);
366 if (retval)
367 goto errout;
368 }
369 if (new_desc_blk) {
370 int meta_bg = i / EXT2_DESC_PER_BLOCK(fs->super);
371
372 retval = io_channel_write_blk64(fs->io, new_desc_blk,
373 1, group_ptr + (meta_bg*fs->blocksize));
374 if (retval)
375 goto errout;
376 }
377 }
378
379 ext2fs_numeric_progress_close(fs, &progress, NULL);
380
381 /*
382 * If the write_bitmaps() function is present, call it to
383 * flush the bitmaps. This is done this way so that a simple
384 * program that doesn't mess with the bitmaps doesn't need to
385 * drag in the bitmaps.c code.
386 */
387 if (fs->write_bitmaps) {
388 retval = fs->write_bitmaps(fs);
389 if (retval)
390 goto errout;
391 }
392
393 write_primary_superblock_only:
394 /*
395 * Write out master superblock. This has to be done
396 * separately, since it is located at a fixed location
397 * (SUPERBLOCK_OFFSET). We flush all other pending changes
398 * out to disk first, just to avoid a race condition with an
399 * insy-tinsy window....
400 */
401
402 fs->super->s_block_group_nr = 0;
403 fs->super->s_state = fs_state;
404 fs->super->s_feature_incompat = feature_incompat;
405 #ifdef WORDS_BIGENDIAN
406 *super_shadow = *fs->super;
407 ext2fs_swap_super(super_shadow);
408 #endif
409
410 if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
411 retval = io_channel_flush(fs->io);
412 retval = write_primary_superblock(fs, super_shadow);
413 if (retval)
414 goto errout;
415
416 fs->flags &= ~EXT2_FLAG_DIRTY;
417
418 if (!(flags & EXT2_FLAG_FLUSH_NO_SYNC))
419 retval = io_channel_flush(fs->io);
420 errout:
421 fs->super->s_state = fs_state;
422 #ifdef WORDS_BIGENDIAN
423 if (super_shadow)
424 ext2fs_free_mem(&super_shadow);
425 if (group_shadow)
426 ext2fs_free_mem(&group_shadow);
427 #endif
428 return retval;
429 }
430
ext2fs_close(ext2_filsys fs)431 errcode_t ext2fs_close(ext2_filsys fs)
432 {
433 return ext2fs_close2(fs, 0);
434 }
435
ext2fs_close2(ext2_filsys fs,int flags)436 errcode_t ext2fs_close2(ext2_filsys fs, int flags)
437 {
438 errcode_t retval;
439 int meta_blks;
440 io_stats stats = 0;
441
442 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
443
444 if (fs->write_bitmaps) {
445 retval = fs->write_bitmaps(fs);
446 if (retval)
447 return retval;
448 }
449 if (fs->super->s_kbytes_written &&
450 fs->io->manager->get_stats)
451 fs->io->manager->get_stats(fs->io, &stats);
452 if (stats && stats->bytes_written && (fs->flags & EXT2_FLAG_RW)) {
453 fs->super->s_kbytes_written += stats->bytes_written >> 10;
454 meta_blks = fs->desc_blocks + 1;
455 if (!(fs->flags & EXT2_FLAG_SUPER_ONLY))
456 fs->super->s_kbytes_written += meta_blks /
457 (fs->blocksize / 1024);
458 if ((fs->flags & EXT2_FLAG_DIRTY) == 0)
459 fs->flags |= EXT2_FLAG_SUPER_ONLY | EXT2_FLAG_DIRTY;
460 }
461 if (fs->flags & EXT2_FLAG_DIRTY) {
462 retval = ext2fs_flush2(fs, flags);
463 if (retval)
464 return retval;
465 }
466
467 retval = ext2fs_mmp_stop(fs);
468 if (retval)
469 return retval;
470
471 ext2fs_free(fs);
472 return 0;
473 }
474
475