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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
12#define EXT3FS_DEBUG
13
14#include <linux/ext3_jbd.h>
15
16#include <linux/errno.h>
17#include <linux/slab.h>
18
19
20#define outside(b, first, last) ((b) < (first) || (b) >= (last))
21#define inside(b, first, last) ((b) >= (first) && (b) < (last))
22
23static int verify_group_input(struct super_block *sb,
24 struct ext3_new_group_data *input)
25{
26 struct ext3_sb_info *sbi = EXT3_SB(sb);
27 struct ext3_super_block *es = sbi->s_es;
28 ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
29 ext3_fsblk_t end = start + input->blocks_count;
30 unsigned group = input->group;
31 ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
32 unsigned overhead = ext3_bg_has_super(sb, group) ?
33 (1 + ext3_bg_num_gdb(sb, group) +
34 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
35 ext3_fsblk_t metaend = start + overhead;
36 struct buffer_head *bh = NULL;
37 ext3_grpblk_t free_blocks_count;
38 int err = -EINVAL;
39
40 input->free_blocks_count = free_blocks_count =
41 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
42
43 if (test_opt(sb, DEBUG))
44 printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
45 "(%d free, %u reserved)\n",
46 ext3_bg_has_super(sb, input->group) ? "normal" :
47 "no-super", input->group, input->blocks_count,
48 free_blocks_count, input->reserved_blocks);
49
50 if (group != sbi->s_groups_count)
51 ext3_warning(sb, __func__,
52 "Cannot add at group %u (only %lu groups)",
53 input->group, sbi->s_groups_count);
54 else if ((start - le32_to_cpu(es->s_first_data_block)) %
55 EXT3_BLOCKS_PER_GROUP(sb))
56 ext3_warning(sb, __func__, "Last group not full");
57 else if (input->reserved_blocks > input->blocks_count / 5)
58 ext3_warning(sb, __func__, "Reserved blocks too high (%u)",
59 input->reserved_blocks);
60 else if (free_blocks_count < 0)
61 ext3_warning(sb, __func__, "Bad blocks count %u",
62 input->blocks_count);
63 else if (!(bh = sb_bread(sb, end - 1)))
64 ext3_warning(sb, __func__,
65 "Cannot read last block ("E3FSBLK")",
66 end - 1);
67 else if (outside(input->block_bitmap, start, end))
68 ext3_warning(sb, __func__,
69 "Block bitmap not in group (block %u)",
70 input->block_bitmap);
71 else if (outside(input->inode_bitmap, start, end))
72 ext3_warning(sb, __func__,
73 "Inode bitmap not in group (block %u)",
74 input->inode_bitmap);
75 else if (outside(input->inode_table, start, end) ||
76 outside(itend - 1, start, end))
77 ext3_warning(sb, __func__,
78 "Inode table not in group (blocks %u-"E3FSBLK")",
79 input->inode_table, itend - 1);
80 else if (input->inode_bitmap == input->block_bitmap)
81 ext3_warning(sb, __func__,
82 "Block bitmap same as inode bitmap (%u)",
83 input->block_bitmap);
84 else if (inside(input->block_bitmap, input->inode_table, itend))
85 ext3_warning(sb, __func__,
86 "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
87 input->block_bitmap, input->inode_table, itend-1);
88 else if (inside(input->inode_bitmap, input->inode_table, itend))
89 ext3_warning(sb, __func__,
90 "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
91 input->inode_bitmap, input->inode_table, itend-1);
92 else if (inside(input->block_bitmap, start, metaend))
93 ext3_warning(sb, __func__,
94 "Block bitmap (%u) in GDT table"
95 " ("E3FSBLK"-"E3FSBLK")",
96 input->block_bitmap, start, metaend - 1);
97 else if (inside(input->inode_bitmap, start, metaend))
98 ext3_warning(sb, __func__,
99 "Inode bitmap (%u) in GDT table"
100 " ("E3FSBLK"-"E3FSBLK")",
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, __func__,
105 "Inode table (%u-"E3FSBLK") overlaps"
106 "GDT table ("E3FSBLK"-"E3FSBLK")",
107 input->inode_table, itend - 1, start, metaend - 1);
108 else
109 err = 0;
110 brelse(bh);
111
112 return err;
113}
114
115static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
116 ext3_fsblk_t blk)
117{
118 struct buffer_head *bh;
119 int err;
120
121 bh = sb_getblk(sb, blk);
122 if (!bh)
123 return ERR_PTR(-EIO);
124 if ((err = ext3_journal_get_write_access(handle, bh))) {
125 brelse(bh);
126 bh = ERR_PTR(err);
127 } else {
128 lock_buffer(bh);
129 memset(bh->b_data, 0, sb->s_blocksize);
130 set_buffer_uptodate(bh);
131 unlock_buffer(bh);
132 }
133
134 return bh;
135}
136
137/*
138 * To avoid calling the atomic setbit hundreds or thousands of times, we only
139 * need to use it within a single byte (to ensure we get endianness right).
140 * We can use memset for the rest of the bitmap as there are no other users.
141 */
142static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
143{
144 int i;
145
146 if (start_bit >= end_bit)
147 return;
148
149 ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
150 for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
151 ext3_set_bit(i, bitmap);
152 if (i < end_bit)
153 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
154}
155
156/*
157 * If we have fewer than thresh credits, extend by EXT3_MAX_TRANS_DATA.
158 * If that fails, restart the transaction & regain write access for the
159 * buffer head which is used for block_bitmap modifications.
160 */
161static int extend_or_restart_transaction(handle_t *handle, int thresh,
162 struct buffer_head *bh)
163{
164 int err;
165
166 if (handle->h_buffer_credits >= thresh)
167 return 0;
168
169 err = ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA);
170 if (err < 0)
171 return err;
172 if (err) {
173 err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA);
174 if (err)
175 return err;
176 err = ext3_journal_get_write_access(handle, bh);
177 if (err)
178 return err;
179 }
180
181 return 0;
182}
183
184/*
185 * Set up the block and inode bitmaps, and the inode table for the new group.
186 * This doesn't need to be part of the main transaction, since we are only
187 * changing blocks outside the actual filesystem. We still do journaling to
188 * ensure the recovery is correct in case of a failure just after resize.
189 * If any part of this fails, we simply abort the resize.
190 */
191static int setup_new_group_blocks(struct super_block *sb,
192 struct ext3_new_group_data *input)
193{
194 struct ext3_sb_info *sbi = EXT3_SB(sb);
195 ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
196 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
197 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
198 unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
199 struct buffer_head *bh;
200 handle_t *handle;
201 ext3_fsblk_t block;
202 ext3_grpblk_t bit;
203 int i;
204 int err = 0, err2;
205
206 /* This transaction may be extended/restarted along the way */
207 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
208
209 if (IS_ERR(handle))
210 return PTR_ERR(handle);
211
212 mutex_lock(&sbi->s_resize_lock);
213 if (input->group != sbi->s_groups_count) {
214 err = -EBUSY;
215 goto exit_journal;
216 }
217
218 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
219 err = PTR_ERR(bh);
220 goto exit_journal;
221 }
222
223 if (ext3_bg_has_super(sb, input->group)) {
224 ext3_debug("mark backup superblock %#04lx (+0)\n", start);
225 ext3_set_bit(0, bh->b_data);
226 }
227
228 /* Copy all of the GDT blocks into the backup in this group */
229 for (i = 0, bit = 1, block = start + 1;
230 i < gdblocks; i++, block++, bit++) {
231 struct buffer_head *gdb;
232
233 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
234
235 err = extend_or_restart_transaction(handle, 1, bh);
236 if (err)
237 goto exit_bh;
238
239 gdb = sb_getblk(sb, block);
240 if (!gdb) {
241 err = -EIO;
242 goto exit_bh;
243 }
244 if ((err = ext3_journal_get_write_access(handle, gdb))) {
245 brelse(gdb);
246 goto exit_bh;
247 }
248 lock_buffer(gdb);
249 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
250 set_buffer_uptodate(gdb);
251 unlock_buffer(gdb);
252 err = ext3_journal_dirty_metadata(handle, gdb);
253 if (err) {
254 brelse(gdb);
255 goto exit_bh;
256 }
257 ext3_set_bit(bit, bh->b_data);
258 brelse(gdb);
259 }
260
261 /* Zero out all of the reserved backup group descriptor table blocks */
262 for (i = 0, bit = gdblocks + 1, block = start + bit;
263 i < reserved_gdb; i++, block++, bit++) {
264 struct buffer_head *gdb;
265
266 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
267
268 err = extend_or_restart_transaction(handle, 1, bh);
269 if (err)
270 goto exit_bh;
271
272 if (IS_ERR(gdb = bclean(handle, sb, block))) {
273 err = PTR_ERR(gdb);
274 goto exit_bh;
275 }
276 err = ext3_journal_dirty_metadata(handle, gdb);
277 if (err) {
278 brelse(gdb);
279 goto exit_bh;
280 }
281 ext3_set_bit(bit, bh->b_data);
282 brelse(gdb);
283 }
284 ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
285 input->block_bitmap - start);
286 ext3_set_bit(input->block_bitmap - start, bh->b_data);
287 ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
288 input->inode_bitmap - start);
289 ext3_set_bit(input->inode_bitmap - start, bh->b_data);
290
291 /* Zero out all of the inode table blocks */
292 for (i = 0, block = input->inode_table, bit = block - start;
293 i < sbi->s_itb_per_group; i++, bit++, block++) {
294 struct buffer_head *it;
295
296 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
297
298 err = extend_or_restart_transaction(handle, 1, bh);
299 if (err)
300 goto exit_bh;
301
302 if (IS_ERR(it = bclean(handle, sb, block))) {
303 err = PTR_ERR(it);
304 goto exit_bh;
305 }
306 err = ext3_journal_dirty_metadata(handle, it);
307 if (err) {
308 brelse(it);
309 goto exit_bh;
310 }
311 brelse(it);
312 ext3_set_bit(bit, bh->b_data);
313 }
314
315 err = extend_or_restart_transaction(handle, 2, bh);
316 if (err)
317 goto exit_bh;
318
319 mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
320 bh->b_data);
321 err = ext3_journal_dirty_metadata(handle, bh);
322 if (err)
323 goto exit_bh;
324 brelse(bh);
325
326 /* Mark unused entries in inode bitmap used */
327 ext3_debug("clear inode bitmap %#04x (+%ld)\n",
328 input->inode_bitmap, input->inode_bitmap - start);
329 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
330 err = PTR_ERR(bh);
331 goto exit_journal;
332 }
333
334 mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
335 bh->b_data);
336 err = ext3_journal_dirty_metadata(handle, bh);
337exit_bh:
338 brelse(bh);
339
340exit_journal:
341 mutex_unlock(&sbi->s_resize_lock);
342 if ((err2 = ext3_journal_stop(handle)) && !err)
343 err = err2;
344
345 return err;
346}
347
348/*
349 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
350 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
351 * calling this for the first time. In a sparse filesystem it will be the
352 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
353 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
354 */
355static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
356 unsigned *five, unsigned *seven)
357{
358 unsigned *min = three;
359 int mult = 3;
360 unsigned ret;
361
362 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
363 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
364 ret = *min;
365 *min += 1;
366 return ret;
367 }
368
369 if (*five < *min) {
370 min = five;
371 mult = 5;
372 }
373 if (*seven < *min) {
374 min = seven;
375 mult = 7;
376 }
377
378 ret = *min;
379 *min *= mult;
380
381 return ret;
382}
383
384/*
385 * Check that all of the backup GDT blocks are held in the primary GDT block.
386 * It is assumed that they are stored in group order. Returns the number of
387 * groups in current filesystem that have BACKUPS, or -ve error code.
388 */
389static int verify_reserved_gdb(struct super_block *sb,
390 struct buffer_head *primary)
391{
392 const ext3_fsblk_t blk = primary->b_blocknr;
393 const unsigned long end = EXT3_SB(sb)->s_groups_count;
394 unsigned three = 1;
395 unsigned five = 5;
396 unsigned seven = 7;
397 unsigned grp;
398 __le32 *p = (__le32 *)primary->b_data;
399 int gdbackups = 0;
400
401 while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
402 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
403 ext3_warning(sb, __func__,
404 "reserved GDT "E3FSBLK
405 " missing grp %d ("E3FSBLK")",
406 blk, grp,
407 grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
408 return -EINVAL;
409 }
410 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
411 return -EFBIG;
412 }
413
414 return gdbackups;
415}
416
417/*
418 * Called when we need to bring a reserved group descriptor table block into
419 * use from the resize inode. The primary copy of the new GDT block currently
420 * is an indirect block (under the double indirect block in the resize inode).
421 * The new backup GDT blocks will be stored as leaf blocks in this indirect
422 * block, in group order. Even though we know all the block numbers we need,
423 * we check to ensure that the resize inode has actually reserved these blocks.
424 *
425 * Don't need to update the block bitmaps because the blocks are still in use.
426 *
427 * We get all of the error cases out of the way, so that we are sure to not
428 * fail once we start modifying the data on disk, because JBD has no rollback.
429 */
430static int add_new_gdb(handle_t *handle, struct inode *inode,
431 struct ext3_new_group_data *input,
432 struct buffer_head **primary)
433{
434 struct super_block *sb = inode->i_sb;
435 struct ext3_super_block *es = EXT3_SB(sb)->s_es;
436 unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
437 ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
438 struct buffer_head **o_group_desc, **n_group_desc;
439 struct buffer_head *dind;
440 int gdbackups;
441 struct ext3_iloc iloc;
442 __le32 *data;
443 int err;
444
445 if (test_opt(sb, DEBUG))
446 printk(KERN_DEBUG
447 "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
448 gdb_num);
449
450 /*
451 * If we are not using the primary superblock/GDT copy don't resize,
452 * because the user tools have no way of handling this. Probably a
453 * bad time to do it anyways.
454 */
455 if (EXT3_SB(sb)->s_sbh->b_blocknr !=
456 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
457 ext3_warning(sb, __func__,
458 "won't resize using backup superblock at %llu",
459 (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
460 return -EPERM;
461 }
462
463 *primary = sb_bread(sb, gdblock);
464 if (!*primary)
465 return -EIO;
466
467 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
468 err = gdbackups;
469 goto exit_bh;
470 }
471
472 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
473 dind = sb_bread(sb, le32_to_cpu(*data));
474 if (!dind) {
475 err = -EIO;
476 goto exit_bh;
477 }
478
479 data = (__le32 *)dind->b_data;
480 if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
481 ext3_warning(sb, __func__,
482 "new group %u GDT block "E3FSBLK" not reserved",
483 input->group, gdblock);
484 err = -EINVAL;
485 goto exit_dind;
486 }
487
488 if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
489 goto exit_dind;
490
491 if ((err = ext3_journal_get_write_access(handle, *primary)))
492 goto exit_sbh;
493
494 if ((err = ext3_journal_get_write_access(handle, dind)))
495 goto exit_primary;
496
497 /* ext3_reserve_inode_write() gets a reference on the iloc */
498 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
499 goto exit_dindj;
500
501 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
502 GFP_NOFS);
503 if (!n_group_desc) {
504 err = -ENOMEM;
505 ext3_warning (sb, __func__,
506 "not enough memory for %lu groups", gdb_num + 1);
507 goto exit_inode;
508 }
509
510 /*
511 * Finally, we have all of the possible failures behind us...
512 *
513 * Remove new GDT block from inode double-indirect block and clear out
514 * the new GDT block for use (which also "frees" the backup GDT blocks
515 * from the reserved inode). We don't need to change the bitmaps for
516 * these blocks, because they are marked as in-use from being in the
517 * reserved inode, and will become GDT blocks (primary and backup).
518 */
519 data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
520 err = ext3_journal_dirty_metadata(handle, dind);
521 if (err)
522 goto exit_group_desc;
523 brelse(dind);
524 dind = NULL;
525 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
526 err = ext3_mark_iloc_dirty(handle, inode, &iloc);
527 if (err)
528 goto exit_group_desc;
529 memset((*primary)->b_data, 0, sb->s_blocksize);
530 err = ext3_journal_dirty_metadata(handle, *primary);
531 if (err)
532 goto exit_group_desc;
533
534 o_group_desc = EXT3_SB(sb)->s_group_desc;
535 memcpy(n_group_desc, o_group_desc,
536 EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
537 n_group_desc[gdb_num] = *primary;
538 EXT3_SB(sb)->s_group_desc = n_group_desc;
539 EXT3_SB(sb)->s_gdb_count++;
540 kfree(o_group_desc);
541
542 le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
543 err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
544 if (err)
545 goto exit_inode;
546
547 return 0;
548
549exit_group_desc:
550 kfree(n_group_desc);
551exit_inode:
552 //ext3_journal_release_buffer(handle, iloc.bh);
553 brelse(iloc.bh);
554exit_dindj:
555 //ext3_journal_release_buffer(handle, dind);
556exit_primary:
557 //ext3_journal_release_buffer(handle, *primary);
558exit_sbh:
559 //ext3_journal_release_buffer(handle, *primary);
560exit_dind:
561 brelse(dind);
562exit_bh:
563 brelse(*primary);
564
565 ext3_debug("leaving with error %d\n", err);
566 return err;
567}
568
569/*
570 * Called when we are adding a new group which has a backup copy of each of
571 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
572 * We need to add these reserved backup GDT blocks to the resize inode, so
573 * that they are kept for future resizing and not allocated to files.
574 *
575 * Each reserved backup GDT block will go into a different indirect block.
576 * The indirect blocks are actually the primary reserved GDT blocks,
577 * so we know in advance what their block numbers are. We only get the
578 * double-indirect block to verify it is pointing to the primary reserved
579 * GDT blocks so we don't overwrite a data block by accident. The reserved
580 * backup GDT blocks are stored in their reserved primary GDT block.
581 */
582static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
583 struct ext3_new_group_data *input)
584{
585 struct super_block *sb = inode->i_sb;
586 int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
587 struct buffer_head **primary;
588 struct buffer_head *dind;
589 struct ext3_iloc iloc;
590 ext3_fsblk_t blk;
591 __le32 *data, *end;
592 int gdbackups = 0;
593 int res, i;
594 int err;
595
596 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
597 if (!primary)
598 return -ENOMEM;
599
600 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
601 dind = sb_bread(sb, le32_to_cpu(*data));
602 if (!dind) {
603 err = -EIO;
604 goto exit_free;
605 }
606
607 blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
608 data = (__le32 *)dind->b_data + (EXT3_SB(sb)->s_gdb_count %
609 EXT3_ADDR_PER_BLOCK(sb));
610 end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
611
612 /* Get each reserved primary GDT block and verify it holds backups */
613 for (res = 0; res < reserved_gdb; res++, blk++) {
614 if (le32_to_cpu(*data) != blk) {
615 ext3_warning(sb, __func__,
616 "reserved block "E3FSBLK
617 " not at offset %ld",
618 blk,
619 (long)(data - (__le32 *)dind->b_data));
620 err = -EINVAL;
621 goto exit_bh;
622 }
623 primary[res] = sb_bread(sb, blk);
624 if (!primary[res]) {
625 err = -EIO;
626 goto exit_bh;
627 }
628 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
629 brelse(primary[res]);
630 err = gdbackups;
631 goto exit_bh;
632 }
633 if (++data >= end)
634 data = (__le32 *)dind->b_data;
635 }
636
637 for (i = 0; i < reserved_gdb; i++) {
638 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
639 /*
640 int j;
641 for (j = 0; j < i; j++)
642 ext3_journal_release_buffer(handle, primary[j]);
643 */
644 goto exit_bh;
645 }
646 }
647
648 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
649 goto exit_bh;
650
651 /*
652 * Finally we can add each of the reserved backup GDT blocks from
653 * the new group to its reserved primary GDT block.
654 */
655 blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
656 for (i = 0; i < reserved_gdb; i++) {
657 int err2;
658 data = (__le32 *)primary[i]->b_data;
659 /* printk("reserving backup %lu[%u] = %lu\n",
660 primary[i]->b_blocknr, gdbackups,
661 blk + primary[i]->b_blocknr); */
662 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
663 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
664 if (!err)
665 err = err2;
666 }
667 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
668 ext3_mark_iloc_dirty(handle, inode, &iloc);
669
670exit_bh:
671 while (--res >= 0)
672 brelse(primary[res]);
673 brelse(dind);
674
675exit_free:
676 kfree(primary);
677
678 return err;
679}
680
681/*
682 * Update the backup copies of the ext3 metadata. These don't need to be part
683 * of the main resize transaction, because e2fsck will re-write them if there
684 * is a problem (basically only OOM will cause a problem). However, we
685 * _should_ update the backups if possible, in case the primary gets trashed
686 * for some reason and we need to run e2fsck from a backup superblock. The
687 * important part is that the new block and inode counts are in the backup
688 * superblocks, and the location of the new group metadata in the GDT backups.
689 *
690 * We do not need take the s_resize_lock for this, because these
691 * blocks are not otherwise touched by the filesystem code when it is
692 * mounted. We don't need to worry about last changing from
693 * sbi->s_groups_count, because the worst that can happen is that we
694 * do not copy the full number of backups at this time. The resize
695 * which changed s_groups_count will backup again.
696 */
697static void update_backups(struct super_block *sb,
698 int blk_off, char *data, int size)
699{
700 struct ext3_sb_info *sbi = EXT3_SB(sb);
701 const unsigned long last = sbi->s_groups_count;
702 const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
703 unsigned three = 1;
704 unsigned five = 5;
705 unsigned seven = 7;
706 unsigned group;
707 int rest = sb->s_blocksize - size;
708 handle_t *handle;
709 int err = 0, err2;
710
711 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
712 if (IS_ERR(handle)) {
713 group = 1;
714 err = PTR_ERR(handle);
715 goto exit_err;
716 }
717
718 while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
719 struct buffer_head *bh;
720
721 /* Out of journal space, and can't get more - abort - so sad */
722 if (handle->h_buffer_credits == 0 &&
723 ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
724 (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
725 break;
726
727 bh = sb_getblk(sb, group * bpg + blk_off);
728 if (!bh) {
729 err = -EIO;
730 break;
731 }
732 ext3_debug("update metadata backup %#04lx\n",
733 (unsigned long)bh->b_blocknr);
734 if ((err = ext3_journal_get_write_access(handle, bh))) {
735 brelse(bh);
736 break;
737 }
738 lock_buffer(bh);
739 memcpy(bh->b_data, data, size);
740 if (rest)
741 memset(bh->b_data + size, 0, rest);
742 set_buffer_uptodate(bh);
743 unlock_buffer(bh);
744 err = ext3_journal_dirty_metadata(handle, bh);
745 brelse(bh);
746 if (err)
747 break;
748 }
749 if ((err2 = ext3_journal_stop(handle)) && !err)
750 err = err2;
751
752 /*
753 * Ugh! Need to have e2fsck write the backup copies. It is too
754 * late to revert the resize, we shouldn't fail just because of
755 * the backup copies (they are only needed in case of corruption).
756 *
757 * However, if we got here we have a journal problem too, so we
758 * can't really start a transaction to mark the superblock.
759 * Chicken out and just set the flag on the hope it will be written
760 * to disk, and if not - we will simply wait until next fsck.
761 */
762exit_err:
763 if (err) {
764 ext3_warning(sb, __func__,
765 "can't update backup for group %d (err %d), "
766 "forcing fsck on next reboot", group, err);
767 sbi->s_mount_state &= ~EXT3_VALID_FS;
768 sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS);
769 mark_buffer_dirty(sbi->s_sbh);
770 }
771}
772
773/* Add group descriptor data to an existing or new group descriptor block.
774 * Ensure we handle all possible error conditions _before_ we start modifying
775 * the filesystem, because we cannot abort the transaction and not have it
776 * write the data to disk.
777 *
778 * If we are on a GDT block boundary, we need to get the reserved GDT block.
779 * Otherwise, we may need to add backup GDT blocks for a sparse group.
780 *
781 * We only need to hold the superblock lock while we are actually adding
782 * in the new group's counts to the superblock. Prior to that we have
783 * not really "added" the group at all. We re-check that we are still
784 * adding in the last group in case things have changed since verifying.
785 */
786int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
787{
788 struct ext3_sb_info *sbi = EXT3_SB(sb);
789 struct ext3_super_block *es = sbi->s_es;
790 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
791 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
792 struct buffer_head *primary = NULL;
793 struct ext3_group_desc *gdp;
794 struct inode *inode = NULL;
795 handle_t *handle;
796 int gdb_off, gdb_num;
797 int err, err2;
798
799 gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
800 gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
801
802 if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
803 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
804 ext3_warning(sb, __func__,
805 "Can't resize non-sparse filesystem further");
806 return -EPERM;
807 }
808
809 if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
810 le32_to_cpu(es->s_blocks_count)) {
811 ext3_warning(sb, __func__, "blocks_count overflow\n");
812 return -EINVAL;
813 }
814
815 if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
816 le32_to_cpu(es->s_inodes_count)) {
817 ext3_warning(sb, __func__, "inodes_count overflow\n");
818 return -EINVAL;
819 }
820
821 if (reserved_gdb || gdb_off == 0) {
822 if (!EXT3_HAS_COMPAT_FEATURE(sb,
823 EXT3_FEATURE_COMPAT_RESIZE_INODE)
824 || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
825 ext3_warning(sb, __func__,
826 "No reserved GDT blocks, can't resize");
827 return -EPERM;
828 }
829 inode = ext3_iget(sb, EXT3_RESIZE_INO);
830 if (IS_ERR(inode)) {
831 ext3_warning(sb, __func__,
832 "Error opening resize inode");
833 return PTR_ERR(inode);
834 }
835 }
836
837 if ((err = verify_group_input(sb, input)))
838 goto exit_put;
839
840 if ((err = setup_new_group_blocks(sb, input)))
841 goto exit_put;
842
843 /*
844 * We will always be modifying at least the superblock and a GDT
845 * block. If we are adding a group past the last current GDT block,
846 * we will also modify the inode and the dindirect block. If we
847 * are adding a group with superblock/GDT backups we will also
848 * modify each of the reserved GDT dindirect blocks.
849 */
850 handle = ext3_journal_start_sb(sb,
851 ext3_bg_has_super(sb, input->group) ?
852 3 + reserved_gdb : 4);
853 if (IS_ERR(handle)) {
854 err = PTR_ERR(handle);
855 goto exit_put;
856 }
857
858 mutex_lock(&sbi->s_resize_lock);
859 if (input->group != sbi->s_groups_count) {
860 ext3_warning(sb, __func__,
861 "multiple resizers run on filesystem!");
862 err = -EBUSY;
863 goto exit_journal;
864 }
865
866 if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
867 goto exit_journal;
868
869 /*
870 * We will only either add reserved group blocks to a backup group
871 * or remove reserved blocks for the first group in a new group block.
872 * Doing both would be mean more complex code, and sane people don't
873 * use non-sparse filesystems anymore. This is already checked above.
874 */
875 if (gdb_off) {
876 primary = sbi->s_group_desc[gdb_num];
877 if ((err = ext3_journal_get_write_access(handle, primary)))
878 goto exit_journal;
879
880 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
881 (err = reserve_backup_gdb(handle, inode, input)))
882 goto exit_journal;
883 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
884 goto exit_journal;
885
886 /*
887 * OK, now we've set up the new group. Time to make it active.
888 *
889 * We do not lock all allocations via s_resize_lock
890 * so we have to be safe wrt. concurrent accesses the group
891 * data. So we need to be careful to set all of the relevant
892 * group descriptor data etc. *before* we enable the group.
893 *
894 * The key field here is sbi->s_groups_count: as long as
895 * that retains its old value, nobody is going to access the new
896 * group.
897 *
898 * So first we update all the descriptor metadata for the new
899 * group; then we update the total disk blocks count; then we
900 * update the groups count to enable the group; then finally we
901 * update the free space counts so that the system can start
902 * using the new disk blocks.
903 */
904
905 /* Update group descriptor block for new group */
906 gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
907
908 gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
909 gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
910 gdp->bg_inode_table = cpu_to_le32(input->inode_table);
911 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
912 gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
913
914 /*
915 * Make the new blocks and inodes valid next. We do this before
916 * increasing the group count so that once the group is enabled,
917 * all of its blocks and inodes are already valid.
918 *
919 * We always allocate group-by-group, then block-by-block or
920 * inode-by-inode within a group, so enabling these
921 * blocks/inodes before the group is live won't actually let us
922 * allocate the new space yet.
923 */
924 le32_add_cpu(&es->s_blocks_count, input->blocks_count);
925 le32_add_cpu(&es->s_inodes_count, EXT3_INODES_PER_GROUP(sb));
926
927 /*
928 * We need to protect s_groups_count against other CPUs seeing
929 * inconsistent state in the superblock.
930 *
931 * The precise rules we use are:
932 *
933 * * Writers of s_groups_count *must* hold s_resize_lock
934 * AND
935 * * Writers must perform a smp_wmb() after updating all dependent
936 * data and before modifying the groups count
937 *
938 * * Readers must hold s_resize_lock over the access
939 * OR
940 * * Readers must perform an smp_rmb() after reading the groups count
941 * and before reading any dependent data.
942 *
943 * NB. These rules can be relaxed when checking the group count
944 * while freeing data, as we can only allocate from a block
945 * group after serialising against the group count, and we can
946 * only then free after serialising in turn against that
947 * allocation.
948 */
949 smp_wmb();
950
951 /* Update the global fs size fields */
952 sbi->s_groups_count++;
953
954 err = ext3_journal_dirty_metadata(handle, primary);
955 if (err)
956 goto exit_journal;
957
958 /* Update the reserved block counts only once the new group is
959 * active. */
960 le32_add_cpu(&es->s_r_blocks_count, input->reserved_blocks);
961
962 /* Update the free space counts */
963 percpu_counter_add(&sbi->s_freeblocks_counter,
964 input->free_blocks_count);
965 percpu_counter_add(&sbi->s_freeinodes_counter,
966 EXT3_INODES_PER_GROUP(sb));
967
968 err = ext3_journal_dirty_metadata(handle, sbi->s_sbh);
969
970exit_journal:
971 mutex_unlock(&sbi->s_resize_lock);
972 if ((err2 = ext3_journal_stop(handle)) && !err)
973 err = err2;
974 if (!err) {
975 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
976 sizeof(struct ext3_super_block));
977 update_backups(sb, primary->b_blocknr, primary->b_data,
978 primary->b_size);
979 }
980exit_put:
981 iput(inode);
982 return err;
983} /* ext3_group_add */
984
985/* Extend the filesystem to the new number of blocks specified. This entry
986 * point is only used to extend the current filesystem to the end of the last
987 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
988 * for emergencies (because it has no dependencies on reserved blocks).
989 *
990 * If we _really_ wanted, we could use default values to call ext3_group_add()
991 * allow the "remount" trick to work for arbitrary resizing, assuming enough
992 * GDT blocks are reserved to grow to the desired size.
993 */
994int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
995 ext3_fsblk_t n_blocks_count)
996{
997 ext3_fsblk_t o_blocks_count;
998 ext3_grpblk_t last;
999 ext3_grpblk_t add;
1000 struct buffer_head * bh;
1001 handle_t *handle;
1002 int err;
1003 unsigned long freed_blocks;
1004
1005 /* We don't need to worry about locking wrt other resizers just
1006 * yet: we're going to revalidate es->s_blocks_count after
1007 * taking the s_resize_lock below. */
1008 o_blocks_count = le32_to_cpu(es->s_blocks_count);
1009
1010 if (test_opt(sb, DEBUG))
1011 printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK
1012 " up to "E3FSBLK" blocks\n",
1013 o_blocks_count, n_blocks_count);
1014
1015 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1016 return 0;
1017
1018 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1019 printk(KERN_ERR "EXT3-fs: filesystem on %s:"
1020 " too large to resize to "E3FSBLK" blocks safely\n",
1021 sb->s_id, n_blocks_count);
1022 if (sizeof(sector_t) < 8)
1023 ext3_warning(sb, __func__,
1024 "CONFIG_LBDAF not enabled\n");
1025 return -EINVAL;
1026 }
1027
1028 if (n_blocks_count < o_blocks_count) {
1029 ext3_warning(sb, __func__,
1030 "can't shrink FS - resize aborted");
1031 return -EBUSY;
1032 }
1033
1034 /* Handle the remaining blocks in the last group only. */
1035 last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
1036 EXT3_BLOCKS_PER_GROUP(sb);
1037
1038 if (last == 0) {
1039 ext3_warning(sb, __func__,
1040 "need to use ext2online to resize further");
1041 return -EPERM;
1042 }
1043
1044 add = EXT3_BLOCKS_PER_GROUP(sb) - last;
1045
1046 if (o_blocks_count + add < o_blocks_count) {
1047 ext3_warning(sb, __func__, "blocks_count overflow");
1048 return -EINVAL;
1049 }
1050
1051 if (o_blocks_count + add > n_blocks_count)
1052 add = n_blocks_count - o_blocks_count;
1053
1054 if (o_blocks_count + add < n_blocks_count)
1055 ext3_warning(sb, __func__,
1056 "will only finish group ("E3FSBLK
1057 " blocks, %u new)",
1058 o_blocks_count + add, add);
1059
1060 /* See if the device is actually as big as what was requested */
1061 bh = sb_bread(sb, o_blocks_count + add -1);
1062 if (!bh) {
1063 ext3_warning(sb, __func__,
1064 "can't read last block, resize aborted");
1065 return -ENOSPC;
1066 }
1067 brelse(bh);
1068
1069 /* We will update the superblock, one block bitmap, and
1070 * one group descriptor via ext3_free_blocks().
1071 */
1072 handle = ext3_journal_start_sb(sb, 3);
1073 if (IS_ERR(handle)) {
1074 err = PTR_ERR(handle);
1075 ext3_warning(sb, __func__, "error %d on journal start",err);
1076 goto exit_put;
1077 }
1078
1079 mutex_lock(&EXT3_SB(sb)->s_resize_lock);
1080 if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
1081 ext3_warning(sb, __func__,
1082 "multiple resizers run on filesystem!");
1083 mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
1084 ext3_journal_stop(handle);
1085 err = -EBUSY;
1086 goto exit_put;
1087 }
1088
1089 if ((err = ext3_journal_get_write_access(handle,
1090 EXT3_SB(sb)->s_sbh))) {
1091 ext3_warning(sb, __func__,
1092 "error %d on journal write access", err);
1093 mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
1094 ext3_journal_stop(handle);
1095 goto exit_put;
1096 }
1097 es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
1098 err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
1099 mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
1100 if (err) {
1101 ext3_warning(sb, __func__,
1102 "error %d on journal dirty metadata", err);
1103 ext3_journal_stop(handle);
1104 goto exit_put;
1105 }
1106 ext3_debug("freeing blocks "E3FSBLK" through "E3FSBLK"\n",
1107 o_blocks_count, o_blocks_count + add);
1108 ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1109 ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n",
1110 o_blocks_count, o_blocks_count + add);
1111 if ((err = ext3_journal_stop(handle)))
1112 goto exit_put;
1113 if (test_opt(sb, DEBUG))
1114 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
1115 le32_to_cpu(es->s_blocks_count));
1116 update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
1117 sizeof(struct ext3_super_block));
1118exit_put:
1119 return err;
1120} /* ext3_group_extend */