blob: 1be78b4b4de956f7bb9e831a7f3e1c1c489b997b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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);
Glauber de Oliveira Costa2973dfd2005-10-30 15:03:05 -0800121 if (!bh)
122 return ERR_PTR(-EIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 if ((err = ext3_journal_get_write_access(handle, bh))) {
124 brelse(bh);
125 bh = ERR_PTR(err);
126 } else {
127 lock_buffer(bh);
128 memset(bh->b_data, 0, sb->s_blocksize);
129 set_buffer_uptodate(bh);
130 unlock_buffer(bh);
131 }
132
133 return bh;
134}
135
136/*
137 * To avoid calling the atomic setbit hundreds or thousands of times, we only
138 * need to use it within a single byte (to ensure we get endianness right).
139 * We can use memset for the rest of the bitmap as there are no other users.
140 */
141static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
142{
143 int i;
144
145 if (start_bit >= end_bit)
146 return;
147
148 ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
149 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
150 ext3_set_bit(i, bitmap);
151 if (i < end_bit)
152 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
153}
154
155/*
156 * Set up the block and inode bitmaps, and the inode table for the new group.
157 * This doesn't need to be part of the main transaction, since we are only
158 * changing blocks outside the actual filesystem. We still do journaling to
159 * ensure the recovery is correct in case of a failure just after resize.
160 * If any part of this fails, we simply abort the resize.
161 */
162static int setup_new_group_blocks(struct super_block *sb,
163 struct ext3_new_group_data *input)
164{
165 struct ext3_sb_info *sbi = EXT3_SB(sb);
166 unsigned long start = input->group * sbi->s_blocks_per_group +
167 le32_to_cpu(sbi->s_es->s_first_data_block);
168 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
169 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
170 unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
171 struct buffer_head *bh;
172 handle_t *handle;
173 unsigned long block;
174 int bit;
175 int i;
176 int err = 0, err2;
177
178 handle = ext3_journal_start_sb(sb, reserved_gdb + gdblocks +
179 2 + sbi->s_itb_per_group);
180 if (IS_ERR(handle))
181 return PTR_ERR(handle);
182
183 lock_super(sb);
184 if (input->group != sbi->s_groups_count) {
185 err = -EBUSY;
186 goto exit_journal;
187 }
188
189 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
190 err = PTR_ERR(bh);
191 goto exit_journal;
192 }
193
194 if (ext3_bg_has_super(sb, input->group)) {
195 ext3_debug("mark backup superblock %#04lx (+0)\n", start);
196 ext3_set_bit(0, bh->b_data);
197 }
198
199 /* Copy all of the GDT blocks into the backup in this group */
200 for (i = 0, bit = 1, block = start + 1;
201 i < gdblocks; i++, block++, bit++) {
202 struct buffer_head *gdb;
203
204 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
205
206 gdb = sb_getblk(sb, block);
Glauber de Oliveira Costa2973dfd2005-10-30 15:03:05 -0800207 if (!gdb) {
208 err = -EIO;
209 goto exit_bh;
210 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 if ((err = ext3_journal_get_write_access(handle, gdb))) {
212 brelse(gdb);
213 goto exit_bh;
214 }
215 lock_buffer(bh);
216 memcpy(gdb->b_data, sbi->s_group_desc[i], bh->b_size);
217 set_buffer_uptodate(gdb);
218 unlock_buffer(bh);
219 ext3_journal_dirty_metadata(handle, gdb);
220 ext3_set_bit(bit, bh->b_data);
221 brelse(gdb);
222 }
223
224 /* Zero out all of the reserved backup group descriptor table blocks */
225 for (i = 0, bit = gdblocks + 1, block = start + bit;
226 i < reserved_gdb; i++, block++, bit++) {
227 struct buffer_head *gdb;
228
229 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
230
231 if (IS_ERR(gdb = bclean(handle, sb, block))) {
232 err = PTR_ERR(bh);
233 goto exit_bh;
234 }
235 ext3_journal_dirty_metadata(handle, gdb);
236 ext3_set_bit(bit, bh->b_data);
237 brelse(gdb);
238 }
239 ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
240 input->block_bitmap - start);
241 ext3_set_bit(input->block_bitmap - start, bh->b_data);
242 ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
243 input->inode_bitmap - start);
244 ext3_set_bit(input->inode_bitmap - start, bh->b_data);
245
246 /* Zero out all of the inode table blocks */
247 for (i = 0, block = input->inode_table, bit = block - start;
248 i < sbi->s_itb_per_group; i++, bit++, block++) {
249 struct buffer_head *it;
250
Glauber de Oliveira Costa8bdac5d2005-09-22 21:44:26 -0700251 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 if (IS_ERR(it = bclean(handle, sb, block))) {
253 err = PTR_ERR(it);
254 goto exit_bh;
255 }
256 ext3_journal_dirty_metadata(handle, it);
257 brelse(it);
258 ext3_set_bit(bit, bh->b_data);
259 }
260 mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
261 bh->b_data);
262 ext3_journal_dirty_metadata(handle, bh);
263 brelse(bh);
264
265 /* Mark unused entries in inode bitmap used */
266 ext3_debug("clear inode bitmap %#04x (+%ld)\n",
267 input->inode_bitmap, input->inode_bitmap - start);
268 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
269 err = PTR_ERR(bh);
270 goto exit_journal;
271 }
272
273 mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
274 bh->b_data);
275 ext3_journal_dirty_metadata(handle, bh);
276exit_bh:
277 brelse(bh);
278
279exit_journal:
280 unlock_super(sb);
281 if ((err2 = ext3_journal_stop(handle)) && !err)
282 err = err2;
283
284 return err;
285}
286
287/*
288 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
289 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
290 * calling this for the first time. In a sparse filesystem it will be the
291 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
292 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
293 */
294static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
295 unsigned *five, unsigned *seven)
296{
297 unsigned *min = three;
298 int mult = 3;
299 unsigned ret;
300
301 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
302 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
303 ret = *min;
304 *min += 1;
305 return ret;
306 }
307
308 if (*five < *min) {
309 min = five;
310 mult = 5;
311 }
312 if (*seven < *min) {
313 min = seven;
314 mult = 7;
315 }
316
317 ret = *min;
318 *min *= mult;
319
320 return ret;
321}
322
323/*
324 * Check that all of the backup GDT blocks are held in the primary GDT block.
325 * It is assumed that they are stored in group order. Returns the number of
326 * groups in current filesystem that have BACKUPS, or -ve error code.
327 */
328static int verify_reserved_gdb(struct super_block *sb,
329 struct buffer_head *primary)
330{
331 const unsigned long blk = primary->b_blocknr;
332 const unsigned long end = EXT3_SB(sb)->s_groups_count;
333 unsigned three = 1;
334 unsigned five = 5;
335 unsigned seven = 7;
336 unsigned grp;
337 __u32 *p = (__u32 *)primary->b_data;
338 int gdbackups = 0;
339
340 while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
341 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
342 ext3_warning(sb, __FUNCTION__,
343 "reserved GDT %ld missing grp %d (%ld)\n",
344 blk, grp,
345 grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
346 return -EINVAL;
347 }
348 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
349 return -EFBIG;
350 }
351
352 return gdbackups;
353}
354
355/*
356 * Called when we need to bring a reserved group descriptor table block into
357 * use from the resize inode. The primary copy of the new GDT block currently
358 * is an indirect block (under the double indirect block in the resize inode).
359 * The new backup GDT blocks will be stored as leaf blocks in this indirect
360 * block, in group order. Even though we know all the block numbers we need,
361 * we check to ensure that the resize inode has actually reserved these blocks.
362 *
363 * Don't need to update the block bitmaps because the blocks are still in use.
364 *
365 * We get all of the error cases out of the way, so that we are sure to not
366 * fail once we start modifying the data on disk, because JBD has no rollback.
367 */
368static int add_new_gdb(handle_t *handle, struct inode *inode,
369 struct ext3_new_group_data *input,
370 struct buffer_head **primary)
371{
372 struct super_block *sb = inode->i_sb;
373 struct ext3_super_block *es = EXT3_SB(sb)->s_es;
374 unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
375 unsigned long gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
376 struct buffer_head **o_group_desc, **n_group_desc;
377 struct buffer_head *dind;
378 int gdbackups;
379 struct ext3_iloc iloc;
380 __u32 *data;
381 int err;
382
383 if (test_opt(sb, DEBUG))
384 printk(KERN_DEBUG
385 "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
386 gdb_num);
387
388 /*
389 * If we are not using the primary superblock/GDT copy don't resize,
390 * because the user tools have no way of handling this. Probably a
391 * bad time to do it anyways.
392 */
393 if (EXT3_SB(sb)->s_sbh->b_blocknr !=
394 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
395 ext3_warning(sb, __FUNCTION__,
396 "won't resize using backup superblock at %llu\n",
397 (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
398 return -EPERM;
399 }
400
401 *primary = sb_bread(sb, gdblock);
402 if (!*primary)
403 return -EIO;
404
405 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
406 err = gdbackups;
407 goto exit_bh;
408 }
409
410 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
411 dind = sb_bread(sb, le32_to_cpu(*data));
412 if (!dind) {
413 err = -EIO;
414 goto exit_bh;
415 }
416
417 data = (__u32 *)dind->b_data;
418 if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
419 ext3_warning(sb, __FUNCTION__,
420 "new group %u GDT block %lu not reserved\n",
421 input->group, gdblock);
422 err = -EINVAL;
423 goto exit_dind;
424 }
425
426 if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
427 goto exit_dind;
428
429 if ((err = ext3_journal_get_write_access(handle, *primary)))
430 goto exit_sbh;
431
432 if ((err = ext3_journal_get_write_access(handle, dind)))
433 goto exit_primary;
434
435 /* ext3_reserve_inode_write() gets a reference on the iloc */
436 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
437 goto exit_dindj;
438
439 n_group_desc = (struct buffer_head **)kmalloc((gdb_num + 1) *
440 sizeof(struct buffer_head *), GFP_KERNEL);
441 if (!n_group_desc) {
442 err = -ENOMEM;
443 ext3_warning (sb, __FUNCTION__,
444 "not enough memory for %lu groups", gdb_num + 1);
445 goto exit_inode;
446 }
447
448 /*
449 * Finally, we have all of the possible failures behind us...
450 *
451 * Remove new GDT block from inode double-indirect block and clear out
452 * the new GDT block for use (which also "frees" the backup GDT blocks
453 * from the reserved inode). We don't need to change the bitmaps for
454 * these blocks, because they are marked as in-use from being in the
455 * reserved inode, and will become GDT blocks (primary and backup).
456 */
457 data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
458 ext3_journal_dirty_metadata(handle, dind);
459 brelse(dind);
460 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
461 ext3_mark_iloc_dirty(handle, inode, &iloc);
462 memset((*primary)->b_data, 0, sb->s_blocksize);
463 ext3_journal_dirty_metadata(handle, *primary);
464
465 o_group_desc = EXT3_SB(sb)->s_group_desc;
466 memcpy(n_group_desc, o_group_desc,
467 EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
468 n_group_desc[gdb_num] = *primary;
469 EXT3_SB(sb)->s_group_desc = n_group_desc;
470 EXT3_SB(sb)->s_gdb_count++;
471 kfree(o_group_desc);
472
473 es->s_reserved_gdt_blocks =
474 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
475 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
476
477 return 0;
478
479exit_inode:
480 //ext3_journal_release_buffer(handle, iloc.bh);
481 brelse(iloc.bh);
482exit_dindj:
483 //ext3_journal_release_buffer(handle, dind);
484exit_primary:
485 //ext3_journal_release_buffer(handle, *primary);
486exit_sbh:
487 //ext3_journal_release_buffer(handle, *primary);
488exit_dind:
489 brelse(dind);
490exit_bh:
491 brelse(*primary);
492
493 ext3_debug("leaving with error %d\n", err);
494 return err;
495}
496
497/*
498 * Called when we are adding a new group which has a backup copy of each of
499 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
500 * We need to add these reserved backup GDT blocks to the resize inode, so
501 * that they are kept for future resizing and not allocated to files.
502 *
503 * Each reserved backup GDT block will go into a different indirect block.
504 * The indirect blocks are actually the primary reserved GDT blocks,
505 * so we know in advance what their block numbers are. We only get the
506 * double-indirect block to verify it is pointing to the primary reserved
507 * GDT blocks so we don't overwrite a data block by accident. The reserved
508 * backup GDT blocks are stored in their reserved primary GDT block.
509 */
510static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
511 struct ext3_new_group_data *input)
512{
513 struct super_block *sb = inode->i_sb;
514 int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
515 struct buffer_head **primary;
516 struct buffer_head *dind;
517 struct ext3_iloc iloc;
518 unsigned long blk;
519 __u32 *data, *end;
520 int gdbackups = 0;
521 int res, i;
522 int err;
523
524 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
525 if (!primary)
526 return -ENOMEM;
527
528 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
529 dind = sb_bread(sb, le32_to_cpu(*data));
530 if (!dind) {
531 err = -EIO;
532 goto exit_free;
533 }
534
535 blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
536 data = (__u32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
537 end = (__u32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
538
539 /* Get each reserved primary GDT block and verify it holds backups */
540 for (res = 0; res < reserved_gdb; res++, blk++) {
541 if (le32_to_cpu(*data) != blk) {
542 ext3_warning(sb, __FUNCTION__,
543 "reserved block %lu not at offset %ld\n",
544 blk, (long)(data - (__u32 *)dind->b_data));
545 err = -EINVAL;
546 goto exit_bh;
547 }
548 primary[res] = sb_bread(sb, blk);
549 if (!primary[res]) {
550 err = -EIO;
551 goto exit_bh;
552 }
553 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
554 brelse(primary[res]);
555 err = gdbackups;
556 goto exit_bh;
557 }
558 if (++data >= end)
559 data = (__u32 *)dind->b_data;
560 }
561
562 for (i = 0; i < reserved_gdb; i++) {
563 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
564 /*
565 int j;
566 for (j = 0; j < i; j++)
567 ext3_journal_release_buffer(handle, primary[j]);
568 */
569 goto exit_bh;
570 }
571 }
572
573 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
574 goto exit_bh;
575
576 /*
577 * Finally we can add each of the reserved backup GDT blocks from
578 * the new group to its reserved primary GDT block.
579 */
580 blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
581 for (i = 0; i < reserved_gdb; i++) {
582 int err2;
583 data = (__u32 *)primary[i]->b_data;
584 /* printk("reserving backup %lu[%u] = %lu\n",
585 primary[i]->b_blocknr, gdbackups,
586 blk + primary[i]->b_blocknr); */
587 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
588 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
589 if (!err)
590 err = err2;
591 }
592 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
593 ext3_mark_iloc_dirty(handle, inode, &iloc);
594
595exit_bh:
596 while (--res >= 0)
597 brelse(primary[res]);
598 brelse(dind);
599
600exit_free:
601 kfree(primary);
602
603 return err;
604}
605
606/*
607 * Update the backup copies of the ext3 metadata. These don't need to be part
608 * of the main resize transaction, because e2fsck will re-write them if there
609 * is a problem (basically only OOM will cause a problem). However, we
610 * _should_ update the backups if possible, in case the primary gets trashed
611 * for some reason and we need to run e2fsck from a backup superblock. The
612 * important part is that the new block and inode counts are in the backup
613 * superblocks, and the location of the new group metadata in the GDT backups.
614 *
615 * We do not need lock_super() for this, because these blocks are not
616 * otherwise touched by the filesystem code when it is mounted. We don't
617 * need to worry about last changing from sbi->s_groups_count, because the
618 * worst that can happen is that we do not copy the full number of backups
619 * at this time. The resize which changed s_groups_count will backup again.
620 */
621static void update_backups(struct super_block *sb,
622 int blk_off, char *data, int size)
623{
624 struct ext3_sb_info *sbi = EXT3_SB(sb);
625 const unsigned long last = sbi->s_groups_count;
626 const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
627 unsigned three = 1;
628 unsigned five = 5;
629 unsigned seven = 7;
630 unsigned group;
631 int rest = sb->s_blocksize - size;
632 handle_t *handle;
633 int err = 0, err2;
634
635 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
636 if (IS_ERR(handle)) {
637 group = 1;
638 err = PTR_ERR(handle);
639 goto exit_err;
640 }
641
642 while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
643 struct buffer_head *bh;
644
645 /* Out of journal space, and can't get more - abort - so sad */
646 if (handle->h_buffer_credits == 0 &&
647 ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
648 (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
649 break;
650
651 bh = sb_getblk(sb, group * bpg + blk_off);
Glauber de Oliveira Costa2973dfd2005-10-30 15:03:05 -0800652 if (!bh) {
653 err = -EIO;
654 break;
655 }
Glauber de Oliveira Costa8bdac5d2005-09-22 21:44:26 -0700656 ext3_debug("update metadata backup %#04lx\n",
657 (unsigned long)bh->b_blocknr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 if ((err = ext3_journal_get_write_access(handle, bh)))
659 break;
660 lock_buffer(bh);
661 memcpy(bh->b_data, data, size);
662 if (rest)
663 memset(bh->b_data + size, 0, rest);
664 set_buffer_uptodate(bh);
665 unlock_buffer(bh);
666 ext3_journal_dirty_metadata(handle, bh);
667 brelse(bh);
668 }
669 if ((err2 = ext3_journal_stop(handle)) && !err)
670 err = err2;
671
672 /*
673 * Ugh! Need to have e2fsck write the backup copies. It is too
674 * late to revert the resize, we shouldn't fail just because of
675 * the backup copies (they are only needed in case of corruption).
676 *
677 * However, if we got here we have a journal problem too, so we
678 * can't really start a transaction to mark the superblock.
679 * Chicken out and just set the flag on the hope it will be written
680 * to disk, and if not - we will simply wait until next fsck.
681 */
682exit_err:
683 if (err) {
684 ext3_warning(sb, __FUNCTION__,
685 "can't update backup for group %d (err %d), "
686 "forcing fsck on next reboot\n", group, err);
687 sbi->s_mount_state &= ~EXT3_VALID_FS;
688 sbi->s_es->s_state &= ~cpu_to_le16(EXT3_VALID_FS);
689 mark_buffer_dirty(sbi->s_sbh);
690 }
691}
692
693/* Add group descriptor data to an existing or new group descriptor block.
694 * Ensure we handle all possible error conditions _before_ we start modifying
695 * the filesystem, because we cannot abort the transaction and not have it
696 * write the data to disk.
697 *
698 * If we are on a GDT block boundary, we need to get the reserved GDT block.
699 * Otherwise, we may need to add backup GDT blocks for a sparse group.
700 *
701 * We only need to hold the superblock lock while we are actually adding
702 * in the new group's counts to the superblock. Prior to that we have
703 * not really "added" the group at all. We re-check that we are still
704 * adding in the last group in case things have changed since verifying.
705 */
706int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
707{
708 struct ext3_sb_info *sbi = EXT3_SB(sb);
709 struct ext3_super_block *es = sbi->s_es;
710 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
711 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
712 struct buffer_head *primary = NULL;
713 struct ext3_group_desc *gdp;
714 struct inode *inode = NULL;
715 handle_t *handle;
716 int gdb_off, gdb_num;
717 int err, err2;
718
719 gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
720 gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
721
722 if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
723 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
724 ext3_warning(sb, __FUNCTION__,
725 "Can't resize non-sparse filesystem further\n");
726 return -EPERM;
727 }
728
729 if (reserved_gdb || gdb_off == 0) {
730 if (!EXT3_HAS_COMPAT_FEATURE(sb,
731 EXT3_FEATURE_COMPAT_RESIZE_INODE)){
732 ext3_warning(sb, __FUNCTION__,
733 "No reserved GDT blocks, can't resize\n");
734 return -EPERM;
735 }
736 inode = iget(sb, EXT3_RESIZE_INO);
737 if (!inode || is_bad_inode(inode)) {
738 ext3_warning(sb, __FUNCTION__,
739 "Error opening resize inode\n");
740 iput(inode);
741 return -ENOENT;
742 }
743 }
744
745 if ((err = verify_group_input(sb, input)))
746 goto exit_put;
747
748 if ((err = setup_new_group_blocks(sb, input)))
749 goto exit_put;
750
751 /*
752 * We will always be modifying at least the superblock and a GDT
753 * block. If we are adding a group past the last current GDT block,
754 * we will also modify the inode and the dindirect block. If we
755 * are adding a group with superblock/GDT backups we will also
756 * modify each of the reserved GDT dindirect blocks.
757 */
758 handle = ext3_journal_start_sb(sb,
759 ext3_bg_has_super(sb, input->group) ?
760 3 + reserved_gdb : 4);
761 if (IS_ERR(handle)) {
762 err = PTR_ERR(handle);
763 goto exit_put;
764 }
765
766 lock_super(sb);
767 if (input->group != EXT3_SB(sb)->s_groups_count) {
768 ext3_warning(sb, __FUNCTION__,
769 "multiple resizers run on filesystem!\n");
770 goto exit_journal;
771 }
772
773 if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
774 goto exit_journal;
775
776 /*
777 * We will only either add reserved group blocks to a backup group
778 * or remove reserved blocks for the first group in a new group block.
779 * Doing both would be mean more complex code, and sane people don't
780 * use non-sparse filesystems anymore. This is already checked above.
781 */
782 if (gdb_off) {
783 primary = sbi->s_group_desc[gdb_num];
784 if ((err = ext3_journal_get_write_access(handle, primary)))
785 goto exit_journal;
786
787 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
788 (err = reserve_backup_gdb(handle, inode, input)))
789 goto exit_journal;
790 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
791 goto exit_journal;
792
793 /*
794 * OK, now we've set up the new group. Time to make it active.
795 *
796 * Current kernels don't lock all allocations via lock_super(),
797 * so we have to be safe wrt. concurrent accesses the group
798 * data. So we need to be careful to set all of the relevant
799 * group descriptor data etc. *before* we enable the group.
800 *
801 * The key field here is EXT3_SB(sb)->s_groups_count: as long as
802 * that retains its old value, nobody is going to access the new
803 * group.
804 *
805 * So first we update all the descriptor metadata for the new
806 * group; then we update the total disk blocks count; then we
807 * update the groups count to enable the group; then finally we
808 * update the free space counts so that the system can start
809 * using the new disk blocks.
810 */
811
812 /* Update group descriptor block for new group */
813 gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
814
815 gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
816 gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
817 gdp->bg_inode_table = cpu_to_le32(input->inode_table);
818 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
819 gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
820
821 /*
822 * Make the new blocks and inodes valid next. We do this before
823 * increasing the group count so that once the group is enabled,
824 * all of its blocks and inodes are already valid.
825 *
826 * We always allocate group-by-group, then block-by-block or
827 * inode-by-inode within a group, so enabling these
828 * blocks/inodes before the group is live won't actually let us
829 * allocate the new space yet.
830 */
831 es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
832 input->blocks_count);
833 es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
834 EXT3_INODES_PER_GROUP(sb));
835
836 /*
837 * We need to protect s_groups_count against other CPUs seeing
838 * inconsistent state in the superblock.
839 *
840 * The precise rules we use are:
841 *
842 * * Writers of s_groups_count *must* hold lock_super
843 * AND
844 * * Writers must perform a smp_wmb() after updating all dependent
845 * data and before modifying the groups count
846 *
847 * * Readers must hold lock_super() over the access
848 * OR
849 * * Readers must perform an smp_rmb() after reading the groups count
850 * and before reading any dependent data.
851 *
852 * NB. These rules can be relaxed when checking the group count
853 * while freeing data, as we can only allocate from a block
854 * group after serialising against the group count, and we can
855 * only then free after serialising in turn against that
856 * allocation.
857 */
858 smp_wmb();
859
860 /* Update the global fs size fields */
861 EXT3_SB(sb)->s_groups_count++;
862
863 ext3_journal_dirty_metadata(handle, primary);
864
865 /* Update the reserved block counts only once the new group is
866 * active. */
867 es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
868 input->reserved_blocks);
869
870 /* Update the free space counts */
871 percpu_counter_mod(&sbi->s_freeblocks_counter,
872 input->free_blocks_count);
873 percpu_counter_mod(&sbi->s_freeinodes_counter,
874 EXT3_INODES_PER_GROUP(sb));
875
876 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
877 sb->s_dirt = 1;
878
879exit_journal:
880 unlock_super(sb);
881 if ((err2 = ext3_journal_stop(handle)) && !err)
882 err = err2;
883 if (!err) {
884 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
885 sizeof(struct ext3_super_block));
886 update_backups(sb, primary->b_blocknr, primary->b_data,
887 primary->b_size);
888 }
889exit_put:
890 iput(inode);
891 return err;
892} /* ext3_group_add */
893
894/* Extend the filesystem to the new number of blocks specified. This entry
895 * point is only used to extend the current filesystem to the end of the last
896 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
897 * for emergencies (because it has no dependencies on reserved blocks).
898 *
899 * If we _really_ wanted, we could use default values to call ext3_group_add()
900 * allow the "remount" trick to work for arbitrary resizing, assuming enough
901 * GDT blocks are reserved to grow to the desired size.
902 */
903int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
904 unsigned long n_blocks_count)
905{
906 unsigned long o_blocks_count;
907 unsigned long o_groups_count;
908 unsigned long last;
909 int add;
910 struct buffer_head * bh;
911 handle_t *handle;
912 int err, freed_blocks;
913
914 /* We don't need to worry about locking wrt other resizers just
915 * yet: we're going to revalidate es->s_blocks_count after
916 * taking lock_super() below. */
917 o_blocks_count = le32_to_cpu(es->s_blocks_count);
918 o_groups_count = EXT3_SB(sb)->s_groups_count;
919
920 if (test_opt(sb, DEBUG))
921 printk(KERN_DEBUG "EXT3-fs: extending last group from %lu to %lu blocks\n",
922 o_blocks_count, n_blocks_count);
923
924 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
925 return 0;
926
927 if (n_blocks_count < o_blocks_count) {
928 ext3_warning(sb, __FUNCTION__,
929 "can't shrink FS - resize aborted");
930 return -EBUSY;
931 }
932
933 /* Handle the remaining blocks in the last group only. */
934 last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
935 EXT3_BLOCKS_PER_GROUP(sb);
936
937 if (last == 0) {
938 ext3_warning(sb, __FUNCTION__,
939 "need to use ext2online to resize further\n");
940 return -EPERM;
941 }
942
943 add = EXT3_BLOCKS_PER_GROUP(sb) - last;
944
945 if (o_blocks_count + add > n_blocks_count)
946 add = n_blocks_count - o_blocks_count;
947
948 if (o_blocks_count + add < n_blocks_count)
949 ext3_warning(sb, __FUNCTION__,
950 "will only finish group (%lu blocks, %u new)",
951 o_blocks_count + add, add);
952
953 /* See if the device is actually as big as what was requested */
954 bh = sb_bread(sb, o_blocks_count + add -1);
955 if (!bh) {
956 ext3_warning(sb, __FUNCTION__,
957 "can't read last block, resize aborted");
958 return -ENOSPC;
959 }
960 brelse(bh);
961
962 /* We will update the superblock, one block bitmap, and
963 * one group descriptor via ext3_free_blocks().
964 */
965 handle = ext3_journal_start_sb(sb, 3);
966 if (IS_ERR(handle)) {
967 err = PTR_ERR(handle);
968 ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
969 goto exit_put;
970 }
971
972 lock_super(sb);
973 if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
974 ext3_warning(sb, __FUNCTION__,
975 "multiple resizers run on filesystem!\n");
976 err = -EBUSY;
977 goto exit_put;
978 }
979
980 if ((err = ext3_journal_get_write_access(handle,
981 EXT3_SB(sb)->s_sbh))) {
982 ext3_warning(sb, __FUNCTION__,
983 "error %d on journal write access", err);
984 unlock_super(sb);
985 ext3_journal_stop(handle);
986 goto exit_put;
987 }
988 es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
989 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
990 sb->s_dirt = 1;
991 unlock_super(sb);
992 ext3_debug("freeing blocks %ld through %ld\n", o_blocks_count,
993 o_blocks_count + add);
994 ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
995 ext3_debug("freed blocks %ld through %ld\n", o_blocks_count,
996 o_blocks_count + add);
997 if ((err = ext3_journal_stop(handle)))
998 goto exit_put;
999 if (test_opt(sb, DEBUG))
1000 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
1001 le32_to_cpu(es->s_blocks_count));
1002 update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
1003 sizeof(struct ext3_super_block));
1004exit_put:
1005 return err;
1006} /* ext3_group_extend */