aboutsummaryrefslogtreecommitdiffstats
path: root/fs/ext3/resize.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/ext3/resize.c')
-rw-r--r--fs/ext3/resize.c996
1 files changed, 996 insertions, 0 deletions
diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c
new file mode 100644
index 000000000000..2c9f81278d5d
--- /dev/null
+++ b/fs/ext3/resize.c
@@ -0,0 +1,996 @@
1/*
2 * linux/fs/ext3/resize.c
3 *
4 * Support for resizing an ext3 filesystem while it is mounted.
5 *
6 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
7 *
8 * This could probably be made into a module, because it is not often in use.
9 */
10
11#include <linux/config.h>
12
13#define EXT3FS_DEBUG
14
15#include <linux/sched.h>
16#include <linux/smp_lock.h>
17#include <linux/ext3_jbd.h>
18
19#include <linux/errno.h>
20#include <linux/slab.h>
21
22
23#define outside(b, first, last) ((b) < (first) || (b) >= (last))
24#define inside(b, first, last) ((b) >= (first) && (b) < (last))
25
26static int verify_group_input(struct super_block *sb,
27 struct ext3_new_group_data *input)
28{
29 struct ext3_sb_info *sbi = EXT3_SB(sb);
30 struct ext3_super_block *es = sbi->s_es;
31 unsigned start = le32_to_cpu(es->s_blocks_count);
32 unsigned end = start + input->blocks_count;
33 unsigned group = input->group;
34 unsigned itend = input->inode_table + EXT3_SB(sb)->s_itb_per_group;
35 unsigned overhead = ext3_bg_has_super(sb, group) ?
36 (1 + ext3_bg_num_gdb(sb, group) +
37 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
38 unsigned metaend = start + overhead;
39 struct buffer_head *bh = NULL;
40 int free_blocks_count;
41 int err = -EINVAL;
42
43 input->free_blocks_count = free_blocks_count =
44 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
45
46 if (test_opt(sb, DEBUG))
47 printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
48 "(%d free, %u reserved)\n",
49 ext3_bg_has_super(sb, input->group) ? "normal" :
50 "no-super", input->group, input->blocks_count,
51 free_blocks_count, input->reserved_blocks);
52
53 if (group != sbi->s_groups_count)
54 ext3_warning(sb, __FUNCTION__,
55 "Cannot add at group %u (only %lu groups)",
56 input->group, sbi->s_groups_count);
57 else if ((start - le32_to_cpu(es->s_first_data_block)) %
58 EXT3_BLOCKS_PER_GROUP(sb))
59 ext3_warning(sb, __FUNCTION__, "Last group not full");
60 else if (input->reserved_blocks > input->blocks_count / 5)
61 ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
62 input->reserved_blocks);
63 else if (free_blocks_count < 0)
64 ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
65 input->blocks_count);
66 else if (!(bh = sb_bread(sb, end - 1)))
67 ext3_warning(sb, __FUNCTION__, "Cannot read last block (%u)",
68 end - 1);
69 else if (outside(input->block_bitmap, start, end))
70 ext3_warning(sb, __FUNCTION__,
71 "Block bitmap not in group (block %u)",
72 input->block_bitmap);
73 else if (outside(input->inode_bitmap, start, end))
74 ext3_warning(sb, __FUNCTION__,
75 "Inode bitmap not in group (block %u)",
76 input->inode_bitmap);
77 else if (outside(input->inode_table, start, end) ||
78 outside(itend - 1, start, end))
79 ext3_warning(sb, __FUNCTION__,
80 "Inode table not in group (blocks %u-%u)",
81 input->inode_table, itend - 1);
82 else if (input->inode_bitmap == input->block_bitmap)
83 ext3_warning(sb, __FUNCTION__,
84 "Block bitmap same as inode bitmap (%u)",
85 input->block_bitmap);
86 else if (inside(input->block_bitmap, input->inode_table, itend))
87 ext3_warning(sb, __FUNCTION__,
88 "Block bitmap (%u) in inode table (%u-%u)",
89 input->block_bitmap, input->inode_table, itend-1);
90 else if (inside(input->inode_bitmap, input->inode_table, itend))
91 ext3_warning(sb, __FUNCTION__,
92 "Inode bitmap (%u) in inode table (%u-%u)",
93 input->inode_bitmap, input->inode_table, itend-1);
94 else if (inside(input->block_bitmap, start, metaend))
95 ext3_warning(sb, __FUNCTION__,
96 "Block bitmap (%u) in GDT table (%u-%u)",
97 input->block_bitmap, start, metaend - 1);
98 else if (inside(input->inode_bitmap, start, metaend))
99 ext3_warning(sb, __FUNCTION__,
100 "Inode bitmap (%u) in GDT table (%u-%u)",
101 input->inode_bitmap, start, metaend - 1);
102 else if (inside(input->inode_table, start, metaend) ||
103 inside(itend - 1, start, metaend))
104 ext3_warning(sb, __FUNCTION__,
105 "Inode table (%u-%u) overlaps GDT table (%u-%u)",
106 input->inode_table, itend - 1, start, metaend - 1);
107 else
108 err = 0;
109 brelse(bh);
110
111 return err;
112}
113
114static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
115 unsigned long blk)
116{
117 struct buffer_head *bh;
118 int err;
119
120 bh = sb_getblk(sb, blk);
121 if ((err = ext3_journal_get_write_access(handle, bh))) {
122 brelse(bh);
123 bh = ERR_PTR(err);
124 } else {
125 lock_buffer(bh);
126 memset(bh->b_data, 0, sb->s_blocksize);
127 set_buffer_uptodate(bh);
128 unlock_buffer(bh);
129 }
130
131 return bh;
132}
133
134/*
135 * To avoid calling the atomic setbit hundreds or thousands of times, we only
136 * need to use it within a single byte (to ensure we get endianness right).
137 * We can use memset for the rest of the bitmap as there are no other users.
138 */
139static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
140{
141 int i;
142
143 if (start_bit >= end_bit)
144 return;
145
146 ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
147 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
148 ext3_set_bit(i, bitmap);
149 if (i < end_bit)
150 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
151}
152
153/*
154 * Set up the block and inode bitmaps, and the inode table for the new group.
155 * This doesn't need to be part of the main transaction, since we are only
156 * changing blocks outside the actual filesystem. We still do journaling to
157 * ensure the recovery is correct in case of a failure just after resize.
158 * If any part of this fails, we simply abort the resize.
159 */
160static int setup_new_group_blocks(struct super_block *sb,
161 struct ext3_new_group_data *input)
162{
163 struct ext3_sb_info *sbi = EXT3_SB(sb);
164 unsigned long start = input->group * sbi->s_blocks_per_group +
165 le32_to_cpu(sbi->s_es->s_first_data_block);
166 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
167 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
168 unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
169 struct buffer_head *bh;
170 handle_t *handle;
171 unsigned long block;
172 int bit;
173 int i;
174 int err = 0, err2;
175
176 handle = ext3_journal_start_sb(sb, reserved_gdb + gdblocks +
177 2 + sbi->s_itb_per_group);
178 if (IS_ERR(handle))
179 return PTR_ERR(handle);
180
181 lock_super(sb);
182 if (input->group != sbi->s_groups_count) {
183 err = -EBUSY;
184 goto exit_journal;
185 }
186
187 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
188 err = PTR_ERR(bh);
189 goto exit_journal;
190 }
191
192 if (ext3_bg_has_super(sb, input->group)) {
193 ext3_debug("mark backup superblock %#04lx (+0)\n", start);
194 ext3_set_bit(0, bh->b_data);
195 }
196
197 /* Copy all of the GDT blocks into the backup in this group */
198 for (i = 0, bit = 1, block = start + 1;
199 i < gdblocks; i++, block++, bit++) {
200 struct buffer_head *gdb;
201
202 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
203
204 gdb = sb_getblk(sb, block);
205 if ((err = ext3_journal_get_write_access(handle, gdb))) {
206 brelse(gdb);
207 goto exit_bh;
208 }
209 lock_buffer(bh);
210 memcpy(gdb->b_data, sbi->s_group_desc[i], bh->b_size);
211 set_buffer_uptodate(gdb);
212 unlock_buffer(bh);
213 ext3_journal_dirty_metadata(handle, gdb);
214 ext3_set_bit(bit, bh->b_data);
215 brelse(gdb);
216 }
217
218 /* Zero out all of the reserved backup group descriptor table blocks */
219 for (i = 0, bit = gdblocks + 1, block = start + bit;
220 i < reserved_gdb; i++, block++, bit++) {
221 struct buffer_head *gdb;
222
223 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
224
225 if (IS_ERR(gdb = bclean(handle, sb, block))) {
226 err = PTR_ERR(bh);
227 goto exit_bh;
228 }
229 ext3_journal_dirty_metadata(handle, gdb);
230 ext3_set_bit(bit, bh->b_data);
231 brelse(gdb);
232 }
233 ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
234 input->block_bitmap - start);
235 ext3_set_bit(input->block_bitmap - start, bh->b_data);
236 ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
237 input->inode_bitmap - start);
238 ext3_set_bit(input->inode_bitmap - start, bh->b_data);
239
240 /* Zero out all of the inode table blocks */
241 for (i = 0, block = input->inode_table, bit = block - start;
242 i < sbi->s_itb_per_group; i++, bit++, block++) {
243 struct buffer_head *it;
244
245 ext3_debug("clear inode block %#04x (+%ld)\n", block, bit);
246 if (IS_ERR(it = bclean(handle, sb, block))) {
247 err = PTR_ERR(it);
248 goto exit_bh;
249 }
250 ext3_journal_dirty_metadata(handle, it);
251 brelse(it);
252 ext3_set_bit(bit, bh->b_data);
253 }
254 mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
255 bh->b_data);
256 ext3_journal_dirty_metadata(handle, bh);
257 brelse(bh);
258
259 /* Mark unused entries in inode bitmap used */
260 ext3_debug("clear inode bitmap %#04x (+%ld)\n",
261 input->inode_bitmap, input->inode_bitmap - start);
262 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
263 err = PTR_ERR(bh);
264 goto exit_journal;
265 }
266
267 mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
268 bh->b_data);
269 ext3_journal_dirty_metadata(handle, bh);
270exit_bh:
271 brelse(bh);
272
273exit_journal:
274 unlock_super(sb);
275 if ((err2 = ext3_journal_stop(handle)) && !err)
276 err = err2;
277
278 return err;
279}
280
281/*
282 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
283 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
284 * calling this for the first time. In a sparse filesystem it will be the
285 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
286 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
287 */
288static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
289 unsigned *five, unsigned *seven)
290{
291 unsigned *min = three;
292 int mult = 3;
293 unsigned ret;
294
295 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
296 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
297 ret = *min;
298 *min += 1;
299 return ret;
300 }
301
302 if (*five < *min) {
303 min = five;
304 mult = 5;
305 }
306 if (*seven < *min) {
307 min = seven;
308 mult = 7;
309 }
310
311 ret = *min;
312 *min *= mult;
313
314 return ret;
315}
316
317/*
318 * Check that all of the backup GDT blocks are held in the primary GDT block.
319 * It is assumed that they are stored in group order. Returns the number of
320 * groups in current filesystem that have BACKUPS, or -ve error code.
321 */
322static int verify_reserved_gdb(struct super_block *sb,
323 struct buffer_head *primary)
324{
325 const unsigned long blk = primary->b_blocknr;
326 const unsigned long end = EXT3_SB(sb)->s_groups_count;
327 unsigned three = 1;
328 unsigned five = 5;
329 unsigned seven = 7;
330 unsigned grp;
331 __u32 *p = (__u32 *)primary->b_data;
332 int gdbackups = 0;
333
334 while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
335 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
336 ext3_warning(sb, __FUNCTION__,
337 "reserved GDT %ld missing grp %d (%ld)\n",
338 blk, grp,
339 grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
340 return -EINVAL;
341 }
342 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
343 return -EFBIG;
344 }
345
346 return gdbackups;
347}
348
349/*
350 * Called when we need to bring a reserved group descriptor table block into
351 * use from the resize inode. The primary copy of the new GDT block currently
352 * is an indirect block (under the double indirect block in the resize inode).
353 * The new backup GDT blocks will be stored as leaf blocks in this indirect
354 * block, in group order. Even though we know all the block numbers we need,
355 * we check to ensure that the resize inode has actually reserved these blocks.
356 *
357 * Don't need to update the block bitmaps because the blocks are still in use.
358 *
359 * We get all of the error cases out of the way, so that we are sure to not
360 * fail once we start modifying the data on disk, because JBD has no rollback.
361 */
362static int add_new_gdb(handle_t *handle, struct inode *inode,
363 struct ext3_new_group_data *input,
364 struct buffer_head **primary)
365{
366 struct super_block *sb = inode->i_sb;
367 struct ext3_super_block *es = EXT3_SB(sb)->s_es;
368 unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
369 unsigned long gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
370 struct buffer_head **o_group_desc, **n_group_desc;
371 struct buffer_head *dind;
372 int gdbackups;
373 struct ext3_iloc iloc;
374 __u32 *data;
375 int err;
376
377 if (test_opt(sb, DEBUG))
378 printk(KERN_DEBUG
379 "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
380 gdb_num);
381
382 /*
383 * If we are not using the primary superblock/GDT copy don't resize,
384 * because the user tools have no way of handling this. Probably a
385 * bad time to do it anyways.
386 */
387 if (EXT3_SB(sb)->s_sbh->b_blocknr !=
388 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
389 ext3_warning(sb, __FUNCTION__,
390 "won't resize using backup superblock at %llu\n",
391 (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
392 return -EPERM;
393 }
394
395 *primary = sb_bread(sb, gdblock);
396 if (!*primary)
397 return -EIO;
398
399 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
400 err = gdbackups;
401 goto exit_bh;
402 }
403
404 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
405 dind = sb_bread(sb, le32_to_cpu(*data));
406 if (!dind) {
407 err = -EIO;
408 goto exit_bh;
409 }
410
411 data = (__u32 *)dind->b_data;
412 if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
413 ext3_warning(sb, __FUNCTION__,
414 "new group %u GDT block %lu not reserved\n",
415 input->group, gdblock);
416 err = -EINVAL;
417 goto exit_dind;
418 }
419
420 if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
421 goto exit_dind;
422
423 if ((err = ext3_journal_get_write_access(handle, *primary)))
424 goto exit_sbh;
425
426 if ((err = ext3_journal_get_write_access(handle, dind)))
427 goto exit_primary;
428
429 /* ext3_reserve_inode_write() gets a reference on the iloc */
430 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
431 goto exit_dindj;
432
433 n_group_desc = (struct buffer_head **)kmalloc((gdb_num + 1) *
434 sizeof(struct buffer_head *), GFP_KERNEL);
435 if (!n_group_desc) {
436 err = -ENOMEM;
437 ext3_warning (sb, __FUNCTION__,
438 "not enough memory for %lu groups", gdb_num + 1);
439 goto exit_inode;
440 }
441
442 /*
443 * Finally, we have all of the possible failures behind us...
444 *
445 * Remove new GDT block from inode double-indirect block and clear out
446 * the new GDT block for use (which also "frees" the backup GDT blocks
447 * from the reserved inode). We don't need to change the bitmaps for
448 * these blocks, because they are marked as in-use from being in the
449 * reserved inode, and will become GDT blocks (primary and backup).
450 */
451 data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
452 ext3_journal_dirty_metadata(handle, dind);
453 brelse(dind);
454 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
455 ext3_mark_iloc_dirty(handle, inode, &iloc);
456 memset((*primary)->b_data, 0, sb->s_blocksize);
457 ext3_journal_dirty_metadata(handle, *primary);
458
459 o_group_desc = EXT3_SB(sb)->s_group_desc;
460 memcpy(n_group_desc, o_group_desc,
461 EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
462 n_group_desc[gdb_num] = *primary;
463 EXT3_SB(sb)->s_group_desc = n_group_desc;
464 EXT3_SB(sb)->s_gdb_count++;
465 kfree(o_group_desc);
466
467 es->s_reserved_gdt_blocks =
468 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
469 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
470
471 return 0;
472
473exit_inode:
474 //ext3_journal_release_buffer(handle, iloc.bh);
475 brelse(iloc.bh);
476exit_dindj:
477 //ext3_journal_release_buffer(handle, dind);
478exit_primary:
479 //ext3_journal_release_buffer(handle, *primary);
480exit_sbh:
481 //ext3_journal_release_buffer(handle, *primary);
482exit_dind:
483 brelse(dind);
484exit_bh:
485 brelse(*primary);
486
487 ext3_debug("leaving with error %d\n", err);
488 return err;
489}
490
491/*
492 * Called when we are adding a new group which has a backup copy of each of
493 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
494 * We need to add these reserved backup GDT blocks to the resize inode, so
495 * that they are kept for future resizing and not allocated to files.
496 *
497 * Each reserved backup GDT block will go into a different indirect block.
498 * The indirect blocks are actually the primary reserved GDT blocks,
499 * so we know in advance what their block numbers are. We only get the
500 * double-indirect block to verify it is pointing to the primary reserved
501 * GDT blocks so we don't overwrite a data block by accident. The reserved
502 * backup GDT blocks are stored in their reserved primary GDT block.
503 */
504static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
505 struct ext3_new_group_data *input)
506{
507 struct super_block *sb = inode->i_sb;
508 int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
509 struct buffer_head **primary;
510 struct buffer_head *dind;
511 struct ext3_iloc iloc;
512 unsigned long blk;
513 __u32 *data, *end;
514 int gdbackups = 0;
515 int res, i;
516 int err;
517
518 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
519 if (!primary)
520 return -ENOMEM;
521
522 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
523 dind = sb_bread(sb, le32_to_cpu(*data));
524 if (!dind) {
525 err = -EIO;
526 goto exit_free;
527 }
528
529 blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
530 data = (__u32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
531 end = (__u32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
532
533 /* Get each reserved primary GDT block and verify it holds backups */
534 for (res = 0; res < reserved_gdb; res++, blk++) {
535 if (le32_to_cpu(*data) != blk) {
536 ext3_warning(sb, __FUNCTION__,
537 "reserved block %lu not at offset %ld\n",
538 blk, (long)(data - (__u32 *)dind->b_data));
539 err = -EINVAL;
540 goto exit_bh;
541 }
542 primary[res] = sb_bread(sb, blk);
543 if (!primary[res]) {
544 err = -EIO;
545 goto exit_bh;
546 }
547 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
548 brelse(primary[res]);
549 err = gdbackups;
550 goto exit_bh;
551 }
552 if (++data >= end)
553 data = (__u32 *)dind->b_data;
554 }
555
556 for (i = 0; i < reserved_gdb; i++) {
557 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
558 /*
559 int j;
560 for (j = 0; j < i; j++)
561 ext3_journal_release_buffer(handle, primary[j]);
562 */
563 goto exit_bh;
564 }
565 }
566
567 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
568 goto exit_bh;
569
570 /*
571 * Finally we can add each of the reserved backup GDT blocks from
572 * the new group to its reserved primary GDT block.
573 */
574 blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
575 for (i = 0; i < reserved_gdb; i++) {
576 int err2;
577 data = (__u32 *)primary[i]->b_data;
578 /* printk("reserving backup %lu[%u] = %lu\n",
579 primary[i]->b_blocknr, gdbackups,
580 blk + primary[i]->b_blocknr); */
581 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
582 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
583 if (!err)
584 err = err2;
585 }
586 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
587 ext3_mark_iloc_dirty(handle, inode, &iloc);
588
589exit_bh:
590 while (--res >= 0)
591 brelse(primary[res]);
592 brelse(dind);
593
594exit_free:
595 kfree(primary);
596
597 return err;
598}
599
600/*
601 * Update the backup copies of the ext3 metadata. These don't need to be part
602 * of the main resize transaction, because e2fsck will re-write them if there
603 * is a problem (basically only OOM will cause a problem). However, we
604 * _should_ update the backups if possible, in case the primary gets trashed
605 * for some reason and we need to run e2fsck from a backup superblock. The
606 * important part is that the new block and inode counts are in the backup
607 * superblocks, and the location of the new group metadata in the GDT backups.
608 *
609 * We do not need lock_super() for this, because these blocks are not
610 * otherwise touched by the filesystem code when it is mounted. We don't
611 * need to worry about last changing from sbi->s_groups_count, because the
612 * worst that can happen is that we do not copy the full number of backups
613 * at this time. The resize which changed s_groups_count will backup again.
614 */
615static void update_backups(struct super_block *sb,
616 int blk_off, char *data, int size)
617{
618 struct ext3_sb_info *sbi = EXT3_SB(sb);
619 const unsigned long last = sbi->s_groups_count;
620 const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
621 unsigned three = 1;
622 unsigned five = 5;
623 unsigned seven = 7;
624 unsigned group;
625 int rest = sb->s_blocksize - size;
626 handle_t *handle;
627 int err = 0, err2;
628
629 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
630 if (IS_ERR(handle)) {
631 group = 1;
632 err = PTR_ERR(handle);
633 goto exit_err;
634 }
635
636 while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
637 struct buffer_head *bh;
638
639 /* Out of journal space, and can't get more - abort - so sad */
640 if (handle->h_buffer_credits == 0 &&
641 ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
642 (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
643 break;
644
645 bh = sb_getblk(sb, group * bpg + blk_off);
646 ext3_debug(sb, __FUNCTION__, "update metadata backup %#04lx\n",
647 bh->b_blocknr);
648 if ((err = ext3_journal_get_write_access(handle, bh)))
649 break;
650 lock_buffer(bh);
651 memcpy(bh->b_data, data, size);
652 if (rest)
653 memset(bh->b_data + size, 0, rest);
654 set_buffer_uptodate(bh);
655 unlock_buffer(bh);
656 ext3_journal_dirty_metadata(handle, bh);
657 brelse(bh);
658 }
659 if ((err2 = ext3_journal_stop(handle)) && !err)
660 err = err2;
661
662 /*
663 * Ugh! Need to have e2fsck write the backup copies. It is too
664 * late to revert the resize, we shouldn't fail just because of
665 * the backup copies (they are only needed in case of corruption).
666 *
667 * However, if we got here we have a journal problem too, so we
668 * can't really start a transaction to mark the superblock.
669 * Chicken out and just set the flag on the hope it will be written
670 * to disk, and if not - we will simply wait until next fsck.
671 */
672exit_err:
673 if (err) {
674 ext3_warning(sb, __FUNCTION__,
675 "can't update backup for group %d (err %d), "
676 "forcing fsck on next reboot\n", group, err);
677 sbi->s_mount_state &= ~EXT3_VALID_FS;
678 sbi->s_es->s_state &= ~cpu_to_le16(EXT3_VALID_FS);
679 mark_buffer_dirty(sbi->s_sbh);
680 }
681}
682
683/* Add group descriptor data to an existing or new group descriptor block.
684 * Ensure we handle all possible error conditions _before_ we start modifying
685 * the filesystem, because we cannot abort the transaction and not have it
686 * write the data to disk.
687 *
688 * If we are on a GDT block boundary, we need to get the reserved GDT block.
689 * Otherwise, we may need to add backup GDT blocks for a sparse group.
690 *
691 * We only need to hold the superblock lock while we are actually adding
692 * in the new group's counts to the superblock. Prior to that we have
693 * not really "added" the group at all. We re-check that we are still
694 * adding in the last group in case things have changed since verifying.
695 */
696int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
697{
698 struct ext3_sb_info *sbi = EXT3_SB(sb);
699 struct ext3_super_block *es = sbi->s_es;
700 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
701 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
702 struct buffer_head *primary = NULL;
703 struct ext3_group_desc *gdp;
704 struct inode *inode = NULL;
705 handle_t *handle;
706 int gdb_off, gdb_num;
707 int err, err2;
708
709 gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
710 gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
711
712 if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
713 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
714 ext3_warning(sb, __FUNCTION__,
715 "Can't resize non-sparse filesystem further\n");
716 return -EPERM;
717 }
718
719 if (reserved_gdb || gdb_off == 0) {
720 if (!EXT3_HAS_COMPAT_FEATURE(sb,
721 EXT3_FEATURE_COMPAT_RESIZE_INODE)){
722 ext3_warning(sb, __FUNCTION__,
723 "No reserved GDT blocks, can't resize\n");
724 return -EPERM;
725 }
726 inode = iget(sb, EXT3_RESIZE_INO);
727 if (!inode || is_bad_inode(inode)) {
728 ext3_warning(sb, __FUNCTION__,
729 "Error opening resize inode\n");
730 iput(inode);
731 return -ENOENT;
732 }
733 }
734
735 if ((err = verify_group_input(sb, input)))
736 goto exit_put;
737
738 if ((err = setup_new_group_blocks(sb, input)))
739 goto exit_put;
740
741 /*
742 * We will always be modifying at least the superblock and a GDT
743 * block. If we are adding a group past the last current GDT block,
744 * we will also modify the inode and the dindirect block. If we
745 * are adding a group with superblock/GDT backups we will also
746 * modify each of the reserved GDT dindirect blocks.
747 */
748 handle = ext3_journal_start_sb(sb,
749 ext3_bg_has_super(sb, input->group) ?
750 3 + reserved_gdb : 4);
751 if (IS_ERR(handle)) {
752 err = PTR_ERR(handle);
753 goto exit_put;
754 }
755
756 lock_super(sb);
757 if (input->group != EXT3_SB(sb)->s_groups_count) {
758 ext3_warning(sb, __FUNCTION__,
759 "multiple resizers run on filesystem!\n");
760 goto exit_journal;
761 }
762
763 if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
764 goto exit_journal;
765
766 /*
767 * We will only either add reserved group blocks to a backup group
768 * or remove reserved blocks for the first group in a new group block.
769 * Doing both would be mean more complex code, and sane people don't
770 * use non-sparse filesystems anymore. This is already checked above.
771 */
772 if (gdb_off) {
773 primary = sbi->s_group_desc[gdb_num];
774 if ((err = ext3_journal_get_write_access(handle, primary)))
775 goto exit_journal;
776
777 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
778 (err = reserve_backup_gdb(handle, inode, input)))
779 goto exit_journal;
780 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
781 goto exit_journal;
782
783 /*
784 * OK, now we've set up the new group. Time to make it active.
785 *
786 * Current kernels don't lock all allocations via lock_super(),
787 * so we have to be safe wrt. concurrent accesses the group
788 * data. So we need to be careful to set all of the relevant
789 * group descriptor data etc. *before* we enable the group.
790 *
791 * The key field here is EXT3_SB(sb)->s_groups_count: as long as
792 * that retains its old value, nobody is going to access the new
793 * group.
794 *
795 * So first we update all the descriptor metadata for the new
796 * group; then we update the total disk blocks count; then we
797 * update the groups count to enable the group; then finally we
798 * update the free space counts so that the system can start
799 * using the new disk blocks.
800 */
801
802 /* Update group descriptor block for new group */
803 gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
804
805 gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
806 gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
807 gdp->bg_inode_table = cpu_to_le32(input->inode_table);
808 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
809 gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
810
811 /*
812 * Make the new blocks and inodes valid next. We do this before
813 * increasing the group count so that once the group is enabled,
814 * all of its blocks and inodes are already valid.
815 *
816 * We always allocate group-by-group, then block-by-block or
817 * inode-by-inode within a group, so enabling these
818 * blocks/inodes before the group is live won't actually let us
819 * allocate the new space yet.
820 */
821 es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
822 input->blocks_count);
823 es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
824 EXT3_INODES_PER_GROUP(sb));
825
826 /*
827 * We need to protect s_groups_count against other CPUs seeing
828 * inconsistent state in the superblock.
829 *
830 * The precise rules we use are:
831 *
832 * * Writers of s_groups_count *must* hold lock_super
833 * AND
834 * * Writers must perform a smp_wmb() after updating all dependent
835 * data and before modifying the groups count
836 *
837 * * Readers must hold lock_super() over the access
838 * OR
839 * * Readers must perform an smp_rmb() after reading the groups count
840 * and before reading any dependent data.
841 *
842 * NB. These rules can be relaxed when checking the group count
843 * while freeing data, as we can only allocate from a block
844 * group after serialising against the group count, and we can
845 * only then free after serialising in turn against that
846 * allocation.
847 */
848 smp_wmb();
849
850 /* Update the global fs size fields */
851 EXT3_SB(sb)->s_groups_count++;
852
853 ext3_journal_dirty_metadata(handle, primary);
854
855 /* Update the reserved block counts only once the new group is
856 * active. */
857 es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
858 input->reserved_blocks);
859
860 /* Update the free space counts */
861 percpu_counter_mod(&sbi->s_freeblocks_counter,
862 input->free_blocks_count);
863 percpu_counter_mod(&sbi->s_freeinodes_counter,
864 EXT3_INODES_PER_GROUP(sb));
865
866 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
867 sb->s_dirt = 1;
868
869exit_journal:
870 unlock_super(sb);
871 if ((err2 = ext3_journal_stop(handle)) && !err)
872 err = err2;
873 if (!err) {
874 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
875 sizeof(struct ext3_super_block));
876 update_backups(sb, primary->b_blocknr, primary->b_data,
877 primary->b_size);
878 }
879exit_put:
880 iput(inode);
881 return err;
882} /* ext3_group_add */
883
884/* Extend the filesystem to the new number of blocks specified. This entry
885 * point is only used to extend the current filesystem to the end of the last
886 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
887 * for emergencies (because it has no dependencies on reserved blocks).
888 *
889 * If we _really_ wanted, we could use default values to call ext3_group_add()
890 * allow the "remount" trick to work for arbitrary resizing, assuming enough
891 * GDT blocks are reserved to grow to the desired size.
892 */
893int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
894 unsigned long n_blocks_count)
895{
896 unsigned long o_blocks_count;
897 unsigned long o_groups_count;
898 unsigned long last;
899 int add;
900 struct buffer_head * bh;
901 handle_t *handle;
902 int err, freed_blocks;
903
904 /* We don't need to worry about locking wrt other resizers just
905 * yet: we're going to revalidate es->s_blocks_count after
906 * taking lock_super() below. */
907 o_blocks_count = le32_to_cpu(es->s_blocks_count);
908 o_groups_count = EXT3_SB(sb)->s_groups_count;
909
910 if (test_opt(sb, DEBUG))
911 printk(KERN_DEBUG "EXT3-fs: extending last group from %lu to %lu blocks\n",
912 o_blocks_count, n_blocks_count);
913
914 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
915 return 0;
916
917 if (n_blocks_count < o_blocks_count) {
918 ext3_warning(sb, __FUNCTION__,
919 "can't shrink FS - resize aborted");
920 return -EBUSY;
921 }
922
923 /* Handle the remaining blocks in the last group only. */
924 last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
925 EXT3_BLOCKS_PER_GROUP(sb);
926
927 if (last == 0) {
928 ext3_warning(sb, __FUNCTION__,
929 "need to use ext2online to resize further\n");
930 return -EPERM;
931 }
932
933 add = EXT3_BLOCKS_PER_GROUP(sb) - last;
934
935 if (o_blocks_count + add > n_blocks_count)
936 add = n_blocks_count - o_blocks_count;
937
938 if (o_blocks_count + add < n_blocks_count)
939 ext3_warning(sb, __FUNCTION__,
940 "will only finish group (%lu blocks, %u new)",
941 o_blocks_count + add, add);
942
943 /* See if the device is actually as big as what was requested */
944 bh = sb_bread(sb, o_blocks_count + add -1);
945 if (!bh) {
946 ext3_warning(sb, __FUNCTION__,
947 "can't read last block, resize aborted");
948 return -ENOSPC;
949 }
950 brelse(bh);
951
952 /* We will update the superblock, one block bitmap, and
953 * one group descriptor via ext3_free_blocks().
954 */
955 handle = ext3_journal_start_sb(sb, 3);
956 if (IS_ERR(handle)) {
957 err = PTR_ERR(handle);
958 ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
959 goto exit_put;
960 }
961
962 lock_super(sb);
963 if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
964 ext3_warning(sb, __FUNCTION__,
965 "multiple resizers run on filesystem!\n");
966 err = -EBUSY;
967 goto exit_put;
968 }
969
970 if ((err = ext3_journal_get_write_access(handle,
971 EXT3_SB(sb)->s_sbh))) {
972 ext3_warning(sb, __FUNCTION__,
973 "error %d on journal write access", err);
974 unlock_super(sb);
975 ext3_journal_stop(handle);
976 goto exit_put;
977 }
978 es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
979 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
980 sb->s_dirt = 1;
981 unlock_super(sb);
982 ext3_debug("freeing blocks %ld through %ld\n", o_blocks_count,
983 o_blocks_count + add);
984 ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
985 ext3_debug("freed blocks %ld through %ld\n", o_blocks_count,
986 o_blocks_count + add);
987 if ((err = ext3_journal_stop(handle)))
988 goto exit_put;
989 if (test_opt(sb, DEBUG))
990 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
991 le32_to_cpu(es->s_blocks_count));
992 update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
993 sizeof(struct ext3_super_block));
994exit_put:
995 return err;
996} /* ext3_group_extend */
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-27 19:20:26 -0500