blob: 7ba7f22e215c615c06a0cb69ff7f64340ea514d4 [file] [log] [blame]
Denis Vlasenkoc4f623e2006-12-26 01:30:59 +00001/* vi: set sw=4 ts=4: */
2/*
3 * closefs.c --- close an ext2 filesystem
4 *
5 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Public
9 * License.
10 * %End-Header%
11 */
12
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
23static int test_root(int a, int b)
24{
25 if (a == 0)
26 return 1;
27 while (1) {
28 if (a == 1)
29 return 1;
30 if (a % b)
31 return 0;
32 a = a / b;
33 }
34}
35
36int ext2fs_bg_has_super(ext2_filsys fs, int group_block)
37{
38 if (!(fs->super->s_feature_ro_compat &
39 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
40 return 1;
41
42 if (test_root(group_block, 3) || (test_root(group_block, 5)) ||
43 test_root(group_block, 7))
44 return 1;
45
46 return 0;
47}
48
49int ext2fs_super_and_bgd_loc(ext2_filsys fs,
50 dgrp_t group,
51 blk_t *ret_super_blk,
52 blk_t *ret_old_desc_blk,
53 blk_t *ret_new_desc_blk,
54 int *ret_meta_bg)
55{
56 blk_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
57 unsigned int meta_bg, meta_bg_size;
58 int numblocks, has_super;
59 int old_desc_blocks;
60
61 group_block = fs->super->s_first_data_block +
62 (group * fs->super->s_blocks_per_group);
63
64 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
65 old_desc_blocks = fs->super->s_first_meta_bg;
66 else
67 old_desc_blocks =
68 fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
69
70 if (group == fs->group_desc_count-1) {
71 numblocks = (fs->super->s_blocks_count -
72 fs->super->s_first_data_block) %
73 fs->super->s_blocks_per_group;
74 if (!numblocks)
75 numblocks = fs->super->s_blocks_per_group;
76 } else
77 numblocks = fs->super->s_blocks_per_group;
78
79 has_super = ext2fs_bg_has_super(fs, group);
80
81 if (has_super) {
82 super_blk = group_block;
83 numblocks--;
84 }
85 meta_bg_size = (fs->blocksize / sizeof (struct ext2_group_desc));
86 meta_bg = group / meta_bg_size;
87
88 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
89 (meta_bg < fs->super->s_first_meta_bg)) {
90 if (has_super) {
91 old_desc_blk = group_block + 1;
92 numblocks -= old_desc_blocks;
93 }
94 } else {
95 if (((group % meta_bg_size) == 0) ||
96 ((group % meta_bg_size) == 1) ||
97 ((group % meta_bg_size) == (meta_bg_size-1))) {
98 if (has_super)
99 has_super = 1;
100 new_desc_blk = group_block + has_super;
101 numblocks--;
102 }
103 }
104
105 numblocks -= 2 + fs->inode_blocks_per_group;
106
107 if (ret_super_blk)
108 *ret_super_blk = super_blk;
109 if (ret_old_desc_blk)
110 *ret_old_desc_blk = old_desc_blk;
111 if (ret_new_desc_blk)
112 *ret_new_desc_blk = new_desc_blk;
113 if (ret_meta_bg)
114 *ret_meta_bg = meta_bg;
115 return numblocks;
116}
117
118
119/*
120 * This function forces out the primary superblock. We need to only
121 * write out those fields which we have changed, since if the
122 * filesystem is mounted, it may have changed some of the other
123 * fields.
124 *
125 * It takes as input a superblock which has already been byte swapped
126 * (if necessary).
127 *
128 */
129static errcode_t write_primary_superblock(ext2_filsys fs,
130 struct ext2_super_block *super)
131{
132 __u16 *old_super, *new_super;
133 int check_idx, write_idx, size;
134 errcode_t retval;
135
136 if (!fs->io->manager->write_byte || !fs->orig_super) {
137 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
138 retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE,
139 super);
140 io_channel_set_blksize(fs->io, fs->blocksize);
141 return retval;
142 }
143
144 old_super = (__u16 *) fs->orig_super;
145 new_super = (__u16 *) super;
146
147 for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) {
148 if (old_super[check_idx] == new_super[check_idx])
149 continue;
150 write_idx = check_idx;
151 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++)
152 if (old_super[check_idx] == new_super[check_idx])
153 break;
154 size = 2 * (check_idx - write_idx);
155 retval = io_channel_write_byte(fs->io,
156 SUPERBLOCK_OFFSET + (2 * write_idx), size,
157 new_super + write_idx);
158 if (retval)
159 return retval;
160 }
161 memcpy(fs->orig_super, super, SUPERBLOCK_SIZE);
162 return 0;
163}
164
165
166/*
167 * Updates the revision to EXT2_DYNAMIC_REV
168 */
169void ext2fs_update_dynamic_rev(ext2_filsys fs)
170{
171 struct ext2_super_block *sb = fs->super;
172
173 if (sb->s_rev_level > EXT2_GOOD_OLD_REV)
174 return;
175
176 sb->s_rev_level = EXT2_DYNAMIC_REV;
177 sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
178 sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
179 /* s_uuid is handled by e2fsck already */
180 /* other fields should be left alone */
181}
182
183static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group,
184 blk_t group_block,
185 struct ext2_super_block *super_shadow)
186{
187 dgrp_t sgrp = group;
188
189 if (sgrp > ((1 << 16) - 1))
190 sgrp = (1 << 16) - 1;
191#if BB_BIG_ENDIAN
192 if (fs->flags & EXT2_FLAG_SWAP_BYTES)
193 super_shadow->s_block_group_nr = ext2fs_swab16(sgrp);
194 else
195#endif
196 fs->super->s_block_group_nr = sgrp;
197
198 return io_channel_write_blk(fs->io, group_block, -SUPERBLOCK_SIZE,
199 super_shadow);
200}
201
202
203errcode_t ext2fs_flush(ext2_filsys fs)
204{
205 dgrp_t i;
206 blk_t group_block;
207 errcode_t retval;
208 unsigned long fs_state;
Denys Vlasenko4b1100e2010-03-05 14:10:54 +0100209 struct ext2_super_block *super_shadow = NULL;
210 struct ext2_group_desc *group_shadow = NULL;
Denis Vlasenkoc4f623e2006-12-26 01:30:59 +0000211 char *group_ptr;
212 int old_desc_blocks;
213#if BB_BIG_ENDIAN
214 dgrp_t j;
215 struct ext2_group_desc *s, *t;
216#endif
217
218 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
219
220 fs_state = fs->super->s_state;
221
222 fs->super->s_wtime = time(NULL);
223 fs->super->s_block_group_nr = 0;
224#if BB_BIG_ENDIAN
225 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
226 retval = EXT2_ET_NO_MEMORY;
227 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow);
228 if (retval)
229 goto errout;
230 retval = ext2fs_get_mem((size_t)(fs->blocksize *
231 fs->desc_blocks),
232 &group_shadow);
233 if (retval)
234 goto errout;
235 memset(group_shadow, 0, (size_t) fs->blocksize *
236 fs->desc_blocks);
237
238 /* swap the group descriptors */
239 for (j=0, s=fs->group_desc, t=group_shadow;
240 j < fs->group_desc_count; j++, t++, s++) {
241 *t = *s;
242 ext2fs_swap_group_desc(t);
243 }
244 } else {
245 super_shadow = fs->super;
246 group_shadow = fs->group_desc;
247 }
248#else
249 super_shadow = fs->super;
250 group_shadow = fs->group_desc;
251#endif
252
253 /*
254 * If this is an external journal device, don't write out the
255 * block group descriptors or any of the backup superblocks
256 */
257 if (fs->super->s_feature_incompat &
258 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
259 goto write_primary_superblock_only;
260
261 /*
262 * Set the state of the FS to be non-valid. (The state has
263 * already been backed up earlier, and will be restored after
264 * we write out the backup superblocks.)
265 */
266 fs->super->s_state &= ~EXT2_VALID_FS;
267#if BB_BIG_ENDIAN
268 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
269 *super_shadow = *fs->super;
270 ext2fs_swap_super(super_shadow);
271 }
272#endif
273
274 /*
275 * Write out the master group descriptors, and the backup
276 * superblocks and group descriptors.
277 */
278 group_block = fs->super->s_first_data_block;
279 group_ptr = (char *) group_shadow;
280 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
281 old_desc_blocks = fs->super->s_first_meta_bg;
282 else
283 old_desc_blocks = fs->desc_blocks;
284
285 for (i = 0; i < fs->group_desc_count; i++) {
286 blk_t super_blk, old_desc_blk, new_desc_blk;
287 int meta_bg;
288
289 ext2fs_super_and_bgd_loc(fs, i, &super_blk, &old_desc_blk,
290 &new_desc_blk, &meta_bg);
291
292 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) {
293 retval = write_backup_super(fs, i, super_blk,
294 super_shadow);
295 if (retval)
296 goto errout;
297 }
298 if (fs->flags & EXT2_FLAG_SUPER_ONLY)
299 continue;
300 if ((old_desc_blk) &&
301 (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) {
302 retval = io_channel_write_blk(fs->io,
303 old_desc_blk, old_desc_blocks, group_ptr);
304 if (retval)
305 goto errout;
306 }
307 if (new_desc_blk) {
308 retval = io_channel_write_blk(fs->io, new_desc_blk,
309 1, group_ptr + (meta_bg*fs->blocksize));
310 if (retval)
311 goto errout;
312 }
313 }
314 fs->super->s_block_group_nr = 0;
315 fs->super->s_state = fs_state;
316#if BB_BIG_ENDIAN
317 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
318 *super_shadow = *fs->super;
319 ext2fs_swap_super(super_shadow);
320 }
321#endif
322
323 /*
324 * If the write_bitmaps() function is present, call it to
325 * flush the bitmaps. This is done this way so that a simple
326 * program that doesn't mess with the bitmaps doesn't need to
327 * drag in the bitmaps.c code.
328 */
329 if (fs->write_bitmaps) {
330 retval = fs->write_bitmaps(fs);
331 if (retval)
332 goto errout;
333 }
334
335write_primary_superblock_only:
336 /*
337 * Write out master superblock. This has to be done
338 * separately, since it is located at a fixed location
339 * (SUPERBLOCK_OFFSET). We flush all other pending changes
340 * out to disk first, just to avoid a race condition with an
341 * insy-tinsy window....
342 */
343 retval = io_channel_flush(fs->io);
344 retval = write_primary_superblock(fs, super_shadow);
345 if (retval)
346 goto errout;
347
348 fs->flags &= ~EXT2_FLAG_DIRTY;
349
350 retval = io_channel_flush(fs->io);
351errout:
352 fs->super->s_state = fs_state;
353 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
354 if (super_shadow)
355 ext2fs_free_mem(&super_shadow);
356 if (group_shadow)
357 ext2fs_free_mem(&group_shadow);
358 }
359 return retval;
360}
361
362errcode_t ext2fs_close(ext2_filsys fs)
363{
364 errcode_t retval;
365
366 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
367
368 if (fs->flags & EXT2_FLAG_DIRTY) {
369 retval = ext2fs_flush(fs);
370 if (retval)
371 return retval;
372 }
373 if (fs->write_bitmaps) {
374 retval = fs->write_bitmaps(fs);
375 if (retval)
376 return retval;
377 }
378 ext2fs_free(fs);
379 return 0;
380}
381