ext3: lighten up resize transaction requirements
[linux-2.6/openmoko-kernel.git] / fs / ext3 / resize.c
blob771f7ada15d9a9b516fd0782f8ab3ee793cba48d
1 /*
2 * linux/fs/ext3/resize.c
4 * Support for resizing an ext3 filesystem while it is mounted.
6 * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
8 * This could probably be made into a module, because it is not often in use.
9 */
12 #define EXT3FS_DEBUG
14 #include <linux/ext3_jbd.h>
16 #include <linux/errno.h>
17 #include <linux/slab.h>
20 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
21 #define inside(b, first, last) ((b) >= (first) && (b) < (last))
23 static int verify_group_input(struct super_block *sb,
24 struct ext3_new_group_data *input)
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;
40 input->free_blocks_count = free_blocks_count =
41 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
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);
50 if (group != sbi->s_groups_count)
51 ext3_warning(sb, __FUNCTION__,
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, __FUNCTION__, "Last group not full");
57 else if (input->reserved_blocks > input->blocks_count / 5)
58 ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
59 input->reserved_blocks);
60 else if (free_blocks_count < 0)
61 ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
62 input->blocks_count);
63 else if (!(bh = sb_bread(sb, end - 1)))
64 ext3_warning(sb, __FUNCTION__,
65 "Cannot read last block ("E3FSBLK")",
66 end - 1);
67 else if (outside(input->block_bitmap, start, end))
68 ext3_warning(sb, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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, __FUNCTION__,
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);
112 return err;
115 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
116 ext3_fsblk_t blk)
118 struct buffer_head *bh;
119 int err;
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);
134 return bh;
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.
142 static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
144 int i;
146 if (start_bit >= end_bit)
147 return;
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);
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.
161 static int extend_or_restart_transaction(handle_t *handle, int thresh,
162 struct buffer_head *bh)
164 int err;
166 if (handle->h_buffer_credits >= thresh)
167 return 0;
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;
181 return 0;
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.
191 static int setup_new_group_blocks(struct super_block *sb,
192 struct ext3_new_group_data *input)
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;
206 /* This transaction may be extended/restarted along the way */
207 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
209 if (IS_ERR(handle))
210 return PTR_ERR(handle);
212 lock_super(sb);
213 if (input->group != sbi->s_groups_count) {
214 err = -EBUSY;
215 goto exit_journal;
218 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
219 err = PTR_ERR(bh);
220 goto exit_journal;
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);
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;
233 ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
235 err = extend_or_restart_transaction(handle, 1, bh);
236 if (err)
237 goto exit_bh;
239 gdb = sb_getblk(sb, block);
240 if (!gdb) {
241 err = -EIO;
242 goto exit_bh;
244 if ((err = ext3_journal_get_write_access(handle, gdb))) {
245 brelse(gdb);
246 goto exit_bh;
248 lock_buffer(bh);
249 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size);
250 set_buffer_uptodate(gdb);
251 unlock_buffer(bh);
252 ext3_journal_dirty_metadata(handle, gdb);
253 ext3_set_bit(bit, bh->b_data);
254 brelse(gdb);
257 /* Zero out all of the reserved backup group descriptor table blocks */
258 for (i = 0, bit = gdblocks + 1, block = start + bit;
259 i < reserved_gdb; i++, block++, bit++) {
260 struct buffer_head *gdb;
262 ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
264 err = extend_or_restart_transaction(handle, 1, bh);
265 if (err)
266 goto exit_bh;
268 if (IS_ERR(gdb = bclean(handle, sb, block))) {
269 err = PTR_ERR(bh);
270 goto exit_bh;
272 ext3_journal_dirty_metadata(handle, gdb);
273 ext3_set_bit(bit, bh->b_data);
274 brelse(gdb);
276 ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
277 input->block_bitmap - start);
278 ext3_set_bit(input->block_bitmap - start, bh->b_data);
279 ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
280 input->inode_bitmap - start);
281 ext3_set_bit(input->inode_bitmap - start, bh->b_data);
283 /* Zero out all of the inode table blocks */
284 for (i = 0, block = input->inode_table, bit = block - start;
285 i < sbi->s_itb_per_group; i++, bit++, block++) {
286 struct buffer_head *it;
288 ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
290 err = extend_or_restart_transaction(handle, 1, bh);
291 if (err)
292 goto exit_bh;
294 if (IS_ERR(it = bclean(handle, sb, block))) {
295 err = PTR_ERR(it);
296 goto exit_bh;
298 ext3_journal_dirty_metadata(handle, it);
299 brelse(it);
300 ext3_set_bit(bit, bh->b_data);
303 err = extend_or_restart_transaction(handle, 2, bh);
304 if (err)
305 goto exit_bh;
307 mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
308 bh->b_data);
309 ext3_journal_dirty_metadata(handle, bh);
310 brelse(bh);
312 /* Mark unused entries in inode bitmap used */
313 ext3_debug("clear inode bitmap %#04x (+%ld)\n",
314 input->inode_bitmap, input->inode_bitmap - start);
315 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
316 err = PTR_ERR(bh);
317 goto exit_journal;
320 mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
321 bh->b_data);
322 ext3_journal_dirty_metadata(handle, bh);
323 exit_bh:
324 brelse(bh);
326 exit_journal:
327 unlock_super(sb);
328 if ((err2 = ext3_journal_stop(handle)) && !err)
329 err = err2;
331 return err;
335 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
336 * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
337 * calling this for the first time. In a sparse filesystem it will be the
338 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
339 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
341 static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
342 unsigned *five, unsigned *seven)
344 unsigned *min = three;
345 int mult = 3;
346 unsigned ret;
348 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
349 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
350 ret = *min;
351 *min += 1;
352 return ret;
355 if (*five < *min) {
356 min = five;
357 mult = 5;
359 if (*seven < *min) {
360 min = seven;
361 mult = 7;
364 ret = *min;
365 *min *= mult;
367 return ret;
371 * Check that all of the backup GDT blocks are held in the primary GDT block.
372 * It is assumed that they are stored in group order. Returns the number of
373 * groups in current filesystem that have BACKUPS, or -ve error code.
375 static int verify_reserved_gdb(struct super_block *sb,
376 struct buffer_head *primary)
378 const ext3_fsblk_t blk = primary->b_blocknr;
379 const unsigned long end = EXT3_SB(sb)->s_groups_count;
380 unsigned three = 1;
381 unsigned five = 5;
382 unsigned seven = 7;
383 unsigned grp;
384 __le32 *p = (__le32 *)primary->b_data;
385 int gdbackups = 0;
387 while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
388 if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
389 ext3_warning(sb, __FUNCTION__,
390 "reserved GDT "E3FSBLK
391 " missing grp %d ("E3FSBLK")",
392 blk, grp,
393 grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
394 return -EINVAL;
396 if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
397 return -EFBIG;
400 return gdbackups;
404 * Called when we need to bring a reserved group descriptor table block into
405 * use from the resize inode. The primary copy of the new GDT block currently
406 * is an indirect block (under the double indirect block in the resize inode).
407 * The new backup GDT blocks will be stored as leaf blocks in this indirect
408 * block, in group order. Even though we know all the block numbers we need,
409 * we check to ensure that the resize inode has actually reserved these blocks.
411 * Don't need to update the block bitmaps because the blocks are still in use.
413 * We get all of the error cases out of the way, so that we are sure to not
414 * fail once we start modifying the data on disk, because JBD has no rollback.
416 static int add_new_gdb(handle_t *handle, struct inode *inode,
417 struct ext3_new_group_data *input,
418 struct buffer_head **primary)
420 struct super_block *sb = inode->i_sb;
421 struct ext3_super_block *es = EXT3_SB(sb)->s_es;
422 unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
423 ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
424 struct buffer_head **o_group_desc, **n_group_desc;
425 struct buffer_head *dind;
426 int gdbackups;
427 struct ext3_iloc iloc;
428 __le32 *data;
429 int err;
431 if (test_opt(sb, DEBUG))
432 printk(KERN_DEBUG
433 "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
434 gdb_num);
437 * If we are not using the primary superblock/GDT copy don't resize,
438 * because the user tools have no way of handling this. Probably a
439 * bad time to do it anyways.
441 if (EXT3_SB(sb)->s_sbh->b_blocknr !=
442 le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
443 ext3_warning(sb, __FUNCTION__,
444 "won't resize using backup superblock at %llu",
445 (unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
446 return -EPERM;
449 *primary = sb_bread(sb, gdblock);
450 if (!*primary)
451 return -EIO;
453 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
454 err = gdbackups;
455 goto exit_bh;
458 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
459 dind = sb_bread(sb, le32_to_cpu(*data));
460 if (!dind) {
461 err = -EIO;
462 goto exit_bh;
465 data = (__le32 *)dind->b_data;
466 if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
467 ext3_warning(sb, __FUNCTION__,
468 "new group %u GDT block "E3FSBLK" not reserved",
469 input->group, gdblock);
470 err = -EINVAL;
471 goto exit_dind;
474 if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
475 goto exit_dind;
477 if ((err = ext3_journal_get_write_access(handle, *primary)))
478 goto exit_sbh;
480 if ((err = ext3_journal_get_write_access(handle, dind)))
481 goto exit_primary;
483 /* ext3_reserve_inode_write() gets a reference on the iloc */
484 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
485 goto exit_dindj;
487 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
488 GFP_KERNEL);
489 if (!n_group_desc) {
490 err = -ENOMEM;
491 ext3_warning (sb, __FUNCTION__,
492 "not enough memory for %lu groups", gdb_num + 1);
493 goto exit_inode;
497 * Finally, we have all of the possible failures behind us...
499 * Remove new GDT block from inode double-indirect block and clear out
500 * the new GDT block for use (which also "frees" the backup GDT blocks
501 * from the reserved inode). We don't need to change the bitmaps for
502 * these blocks, because they are marked as in-use from being in the
503 * reserved inode, and will become GDT blocks (primary and backup).
505 data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
506 ext3_journal_dirty_metadata(handle, dind);
507 brelse(dind);
508 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
509 ext3_mark_iloc_dirty(handle, inode, &iloc);
510 memset((*primary)->b_data, 0, sb->s_blocksize);
511 ext3_journal_dirty_metadata(handle, *primary);
513 o_group_desc = EXT3_SB(sb)->s_group_desc;
514 memcpy(n_group_desc, o_group_desc,
515 EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
516 n_group_desc[gdb_num] = *primary;
517 EXT3_SB(sb)->s_group_desc = n_group_desc;
518 EXT3_SB(sb)->s_gdb_count++;
519 kfree(o_group_desc);
521 es->s_reserved_gdt_blocks =
522 cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
523 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
525 return 0;
527 exit_inode:
528 //ext3_journal_release_buffer(handle, iloc.bh);
529 brelse(iloc.bh);
530 exit_dindj:
531 //ext3_journal_release_buffer(handle, dind);
532 exit_primary:
533 //ext3_journal_release_buffer(handle, *primary);
534 exit_sbh:
535 //ext3_journal_release_buffer(handle, *primary);
536 exit_dind:
537 brelse(dind);
538 exit_bh:
539 brelse(*primary);
541 ext3_debug("leaving with error %d\n", err);
542 return err;
546 * Called when we are adding a new group which has a backup copy of each of
547 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
548 * We need to add these reserved backup GDT blocks to the resize inode, so
549 * that they are kept for future resizing and not allocated to files.
551 * Each reserved backup GDT block will go into a different indirect block.
552 * The indirect blocks are actually the primary reserved GDT blocks,
553 * so we know in advance what their block numbers are. We only get the
554 * double-indirect block to verify it is pointing to the primary reserved
555 * GDT blocks so we don't overwrite a data block by accident. The reserved
556 * backup GDT blocks are stored in their reserved primary GDT block.
558 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
559 struct ext3_new_group_data *input)
561 struct super_block *sb = inode->i_sb;
562 int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
563 struct buffer_head **primary;
564 struct buffer_head *dind;
565 struct ext3_iloc iloc;
566 ext3_fsblk_t blk;
567 __le32 *data, *end;
568 int gdbackups = 0;
569 int res, i;
570 int err;
572 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
573 if (!primary)
574 return -ENOMEM;
576 data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
577 dind = sb_bread(sb, le32_to_cpu(*data));
578 if (!dind) {
579 err = -EIO;
580 goto exit_free;
583 blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
584 data = (__le32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
585 end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
587 /* Get each reserved primary GDT block and verify it holds backups */
588 for (res = 0; res < reserved_gdb; res++, blk++) {
589 if (le32_to_cpu(*data) != blk) {
590 ext3_warning(sb, __FUNCTION__,
591 "reserved block "E3FSBLK
592 " not at offset %ld",
593 blk,
594 (long)(data - (__le32 *)dind->b_data));
595 err = -EINVAL;
596 goto exit_bh;
598 primary[res] = sb_bread(sb, blk);
599 if (!primary[res]) {
600 err = -EIO;
601 goto exit_bh;
603 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
604 brelse(primary[res]);
605 err = gdbackups;
606 goto exit_bh;
608 if (++data >= end)
609 data = (__le32 *)dind->b_data;
612 for (i = 0; i < reserved_gdb; i++) {
613 if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
615 int j;
616 for (j = 0; j < i; j++)
617 ext3_journal_release_buffer(handle, primary[j]);
619 goto exit_bh;
623 if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
624 goto exit_bh;
627 * Finally we can add each of the reserved backup GDT blocks from
628 * the new group to its reserved primary GDT block.
630 blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
631 for (i = 0; i < reserved_gdb; i++) {
632 int err2;
633 data = (__le32 *)primary[i]->b_data;
634 /* printk("reserving backup %lu[%u] = %lu\n",
635 primary[i]->b_blocknr, gdbackups,
636 blk + primary[i]->b_blocknr); */
637 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
638 err2 = ext3_journal_dirty_metadata(handle, primary[i]);
639 if (!err)
640 err = err2;
642 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
643 ext3_mark_iloc_dirty(handle, inode, &iloc);
645 exit_bh:
646 while (--res >= 0)
647 brelse(primary[res]);
648 brelse(dind);
650 exit_free:
651 kfree(primary);
653 return err;
657 * Update the backup copies of the ext3 metadata. These don't need to be part
658 * of the main resize transaction, because e2fsck will re-write them if there
659 * is a problem (basically only OOM will cause a problem). However, we
660 * _should_ update the backups if possible, in case the primary gets trashed
661 * for some reason and we need to run e2fsck from a backup superblock. The
662 * important part is that the new block and inode counts are in the backup
663 * superblocks, and the location of the new group metadata in the GDT backups.
665 * We do not need lock_super() for this, because these blocks are not
666 * otherwise touched by the filesystem code when it is mounted. We don't
667 * need to worry about last changing from sbi->s_groups_count, because the
668 * worst that can happen is that we do not copy the full number of backups
669 * at this time. The resize which changed s_groups_count will backup again.
671 static void update_backups(struct super_block *sb,
672 int blk_off, char *data, int size)
674 struct ext3_sb_info *sbi = EXT3_SB(sb);
675 const unsigned long last = sbi->s_groups_count;
676 const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
677 unsigned three = 1;
678 unsigned five = 5;
679 unsigned seven = 7;
680 unsigned group;
681 int rest = sb->s_blocksize - size;
682 handle_t *handle;
683 int err = 0, err2;
685 handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
686 if (IS_ERR(handle)) {
687 group = 1;
688 err = PTR_ERR(handle);
689 goto exit_err;
692 while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
693 struct buffer_head *bh;
695 /* Out of journal space, and can't get more - abort - so sad */
696 if (handle->h_buffer_credits == 0 &&
697 ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
698 (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
699 break;
701 bh = sb_getblk(sb, group * bpg + blk_off);
702 if (!bh) {
703 err = -EIO;
704 break;
706 ext3_debug("update metadata backup %#04lx\n",
707 (unsigned long)bh->b_blocknr);
708 if ((err = ext3_journal_get_write_access(handle, bh)))
709 break;
710 lock_buffer(bh);
711 memcpy(bh->b_data, data, size);
712 if (rest)
713 memset(bh->b_data + size, 0, rest);
714 set_buffer_uptodate(bh);
715 unlock_buffer(bh);
716 ext3_journal_dirty_metadata(handle, bh);
717 brelse(bh);
719 if ((err2 = ext3_journal_stop(handle)) && !err)
720 err = err2;
723 * Ugh! Need to have e2fsck write the backup copies. It is too
724 * late to revert the resize, we shouldn't fail just because of
725 * the backup copies (they are only needed in case of corruption).
727 * However, if we got here we have a journal problem too, so we
728 * can't really start a transaction to mark the superblock.
729 * Chicken out and just set the flag on the hope it will be written
730 * to disk, and if not - we will simply wait until next fsck.
732 exit_err:
733 if (err) {
734 ext3_warning(sb, __FUNCTION__,
735 "can't update backup for group %d (err %d), "
736 "forcing fsck on next reboot", group, err);
737 sbi->s_mount_state &= ~EXT3_VALID_FS;
738 sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS);
739 mark_buffer_dirty(sbi->s_sbh);
743 /* Add group descriptor data to an existing or new group descriptor block.
744 * Ensure we handle all possible error conditions _before_ we start modifying
745 * the filesystem, because we cannot abort the transaction and not have it
746 * write the data to disk.
748 * If we are on a GDT block boundary, we need to get the reserved GDT block.
749 * Otherwise, we may need to add backup GDT blocks for a sparse group.
751 * We only need to hold the superblock lock while we are actually adding
752 * in the new group's counts to the superblock. Prior to that we have
753 * not really "added" the group at all. We re-check that we are still
754 * adding in the last group in case things have changed since verifying.
756 int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
758 struct ext3_sb_info *sbi = EXT3_SB(sb);
759 struct ext3_super_block *es = sbi->s_es;
760 int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
761 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
762 struct buffer_head *primary = NULL;
763 struct ext3_group_desc *gdp;
764 struct inode *inode = NULL;
765 handle_t *handle;
766 int gdb_off, gdb_num;
767 int err, err2;
769 gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
770 gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
772 if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
773 EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
774 ext3_warning(sb, __FUNCTION__,
775 "Can't resize non-sparse filesystem further");
776 return -EPERM;
779 if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
780 le32_to_cpu(es->s_blocks_count)) {
781 ext3_warning(sb, __FUNCTION__, "blocks_count overflow\n");
782 return -EINVAL;
785 if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
786 le32_to_cpu(es->s_inodes_count)) {
787 ext3_warning(sb, __FUNCTION__, "inodes_count overflow\n");
788 return -EINVAL;
791 if (reserved_gdb || gdb_off == 0) {
792 if (!EXT3_HAS_COMPAT_FEATURE(sb,
793 EXT3_FEATURE_COMPAT_RESIZE_INODE)){
794 ext3_warning(sb, __FUNCTION__,
795 "No reserved GDT blocks, can't resize");
796 return -EPERM;
798 inode = iget(sb, EXT3_RESIZE_INO);
799 if (!inode || is_bad_inode(inode)) {
800 ext3_warning(sb, __FUNCTION__,
801 "Error opening resize inode");
802 iput(inode);
803 return -ENOENT;
807 if ((err = verify_group_input(sb, input)))
808 goto exit_put;
810 if ((err = setup_new_group_blocks(sb, input)))
811 goto exit_put;
814 * We will always be modifying at least the superblock and a GDT
815 * block. If we are adding a group past the last current GDT block,
816 * we will also modify the inode and the dindirect block. If we
817 * are adding a group with superblock/GDT backups we will also
818 * modify each of the reserved GDT dindirect blocks.
820 handle = ext3_journal_start_sb(sb,
821 ext3_bg_has_super(sb, input->group) ?
822 3 + reserved_gdb : 4);
823 if (IS_ERR(handle)) {
824 err = PTR_ERR(handle);
825 goto exit_put;
828 lock_super(sb);
829 if (input->group != sbi->s_groups_count) {
830 ext3_warning(sb, __FUNCTION__,
831 "multiple resizers run on filesystem!");
832 err = -EBUSY;
833 goto exit_journal;
836 if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
837 goto exit_journal;
840 * We will only either add reserved group blocks to a backup group
841 * or remove reserved blocks for the first group in a new group block.
842 * Doing both would be mean more complex code, and sane people don't
843 * use non-sparse filesystems anymore. This is already checked above.
845 if (gdb_off) {
846 primary = sbi->s_group_desc[gdb_num];
847 if ((err = ext3_journal_get_write_access(handle, primary)))
848 goto exit_journal;
850 if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
851 (err = reserve_backup_gdb(handle, inode, input)))
852 goto exit_journal;
853 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
854 goto exit_journal;
857 * OK, now we've set up the new group. Time to make it active.
859 * Current kernels don't lock all allocations via lock_super(),
860 * so we have to be safe wrt. concurrent accesses the group
861 * data. So we need to be careful to set all of the relevant
862 * group descriptor data etc. *before* we enable the group.
864 * The key field here is sbi->s_groups_count: as long as
865 * that retains its old value, nobody is going to access the new
866 * group.
868 * So first we update all the descriptor metadata for the new
869 * group; then we update the total disk blocks count; then we
870 * update the groups count to enable the group; then finally we
871 * update the free space counts so that the system can start
872 * using the new disk blocks.
875 /* Update group descriptor block for new group */
876 gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
878 gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
879 gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
880 gdp->bg_inode_table = cpu_to_le32(input->inode_table);
881 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
882 gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
885 * Make the new blocks and inodes valid next. We do this before
886 * increasing the group count so that once the group is enabled,
887 * all of its blocks and inodes are already valid.
889 * We always allocate group-by-group, then block-by-block or
890 * inode-by-inode within a group, so enabling these
891 * blocks/inodes before the group is live won't actually let us
892 * allocate the new space yet.
894 es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
895 input->blocks_count);
896 es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
897 EXT3_INODES_PER_GROUP(sb));
900 * We need to protect s_groups_count against other CPUs seeing
901 * inconsistent state in the superblock.
903 * The precise rules we use are:
905 * * Writers of s_groups_count *must* hold lock_super
906 * AND
907 * * Writers must perform a smp_wmb() after updating all dependent
908 * data and before modifying the groups count
910 * * Readers must hold lock_super() over the access
911 * OR
912 * * Readers must perform an smp_rmb() after reading the groups count
913 * and before reading any dependent data.
915 * NB. These rules can be relaxed when checking the group count
916 * while freeing data, as we can only allocate from a block
917 * group after serialising against the group count, and we can
918 * only then free after serialising in turn against that
919 * allocation.
921 smp_wmb();
923 /* Update the global fs size fields */
924 sbi->s_groups_count++;
926 ext3_journal_dirty_metadata(handle, primary);
928 /* Update the reserved block counts only once the new group is
929 * active. */
930 es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
931 input->reserved_blocks);
933 /* Update the free space counts */
934 percpu_counter_add(&sbi->s_freeblocks_counter,
935 input->free_blocks_count);
936 percpu_counter_add(&sbi->s_freeinodes_counter,
937 EXT3_INODES_PER_GROUP(sb));
939 ext3_journal_dirty_metadata(handle, sbi->s_sbh);
940 sb->s_dirt = 1;
942 exit_journal:
943 unlock_super(sb);
944 if ((err2 = ext3_journal_stop(handle)) && !err)
945 err = err2;
946 if (!err) {
947 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
948 sizeof(struct ext3_super_block));
949 update_backups(sb, primary->b_blocknr, primary->b_data,
950 primary->b_size);
952 exit_put:
953 iput(inode);
954 return err;
955 } /* ext3_group_add */
957 /* Extend the filesystem to the new number of blocks specified. This entry
958 * point is only used to extend the current filesystem to the end of the last
959 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
960 * for emergencies (because it has no dependencies on reserved blocks).
962 * If we _really_ wanted, we could use default values to call ext3_group_add()
963 * allow the "remount" trick to work for arbitrary resizing, assuming enough
964 * GDT blocks are reserved to grow to the desired size.
966 int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
967 ext3_fsblk_t n_blocks_count)
969 ext3_fsblk_t o_blocks_count;
970 unsigned long o_groups_count;
971 ext3_grpblk_t last;
972 ext3_grpblk_t add;
973 struct buffer_head * bh;
974 handle_t *handle;
975 int err;
976 unsigned long freed_blocks;
978 /* We don't need to worry about locking wrt other resizers just
979 * yet: we're going to revalidate es->s_blocks_count after
980 * taking lock_super() below. */
981 o_blocks_count = le32_to_cpu(es->s_blocks_count);
982 o_groups_count = EXT3_SB(sb)->s_groups_count;
984 if (test_opt(sb, DEBUG))
985 printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK" uto "E3FSBLK" blocks\n",
986 o_blocks_count, n_blocks_count);
988 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
989 return 0;
991 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
992 printk(KERN_ERR "EXT3-fs: filesystem on %s:"
993 " too large to resize to %lu blocks safely\n",
994 sb->s_id, n_blocks_count);
995 if (sizeof(sector_t) < 8)
996 ext3_warning(sb, __FUNCTION__,
997 "CONFIG_LBD not enabled\n");
998 return -EINVAL;
1001 if (n_blocks_count < o_blocks_count) {
1002 ext3_warning(sb, __FUNCTION__,
1003 "can't shrink FS - resize aborted");
1004 return -EBUSY;
1007 /* Handle the remaining blocks in the last group only. */
1008 last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
1009 EXT3_BLOCKS_PER_GROUP(sb);
1011 if (last == 0) {
1012 ext3_warning(sb, __FUNCTION__,
1013 "need to use ext2online to resize further");
1014 return -EPERM;
1017 add = EXT3_BLOCKS_PER_GROUP(sb) - last;
1019 if (o_blocks_count + add < o_blocks_count) {
1020 ext3_warning(sb, __FUNCTION__, "blocks_count overflow");
1021 return -EINVAL;
1024 if (o_blocks_count + add > n_blocks_count)
1025 add = n_blocks_count - o_blocks_count;
1027 if (o_blocks_count + add < n_blocks_count)
1028 ext3_warning(sb, __FUNCTION__,
1029 "will only finish group ("E3FSBLK
1030 " blocks, %u new)",
1031 o_blocks_count + add, add);
1033 /* See if the device is actually as big as what was requested */
1034 bh = sb_bread(sb, o_blocks_count + add -1);
1035 if (!bh) {
1036 ext3_warning(sb, __FUNCTION__,
1037 "can't read last block, resize aborted");
1038 return -ENOSPC;
1040 brelse(bh);
1042 /* We will update the superblock, one block bitmap, and
1043 * one group descriptor via ext3_free_blocks().
1045 handle = ext3_journal_start_sb(sb, 3);
1046 if (IS_ERR(handle)) {
1047 err = PTR_ERR(handle);
1048 ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
1049 goto exit_put;
1052 lock_super(sb);
1053 if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
1054 ext3_warning(sb, __FUNCTION__,
1055 "multiple resizers run on filesystem!");
1056 unlock_super(sb);
1057 err = -EBUSY;
1058 goto exit_put;
1061 if ((err = ext3_journal_get_write_access(handle,
1062 EXT3_SB(sb)->s_sbh))) {
1063 ext3_warning(sb, __FUNCTION__,
1064 "error %d on journal write access", err);
1065 unlock_super(sb);
1066 ext3_journal_stop(handle);
1067 goto exit_put;
1069 es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
1070 ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
1071 sb->s_dirt = 1;
1072 unlock_super(sb);
1073 ext3_debug("freeing blocks %lu through "E3FSBLK"\n", o_blocks_count,
1074 o_blocks_count + add);
1075 ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1076 ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", o_blocks_count,
1077 o_blocks_count + add);
1078 if ((err = ext3_journal_stop(handle)))
1079 goto exit_put;
1080 if (test_opt(sb, DEBUG))
1081 printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
1082 le32_to_cpu(es->s_blocks_count));
1083 update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
1084 sizeof(struct ext3_super_block));
1085 exit_put:
1086 return err;
1087 } /* ext3_group_extend */