2 * linux/fs/ext4/resize.c
4 * Support for resizing an ext4 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.
14 #include <linux/ext4_jbd2.h>
16 #include <linux/errno.h>
17 #include <linux/slab.h>
21 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
22 #define inside(b, first, last) ((b) >= (first) && (b) < (last))
24 static int verify_group_input(struct super_block *sb,
25 struct ext4_new_group_data *input)
27 struct ext4_sb_info *sbi = EXT4_SB(sb);
28 struct ext4_super_block *es = sbi->s_es;
29 ext4_fsblk_t start = ext4_blocks_count(es);
30 ext4_fsblk_t end = start + input->blocks_count;
31 ext4_group_t group = input->group;
32 ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
33 unsigned overhead = ext4_bg_has_super(sb, group) ?
34 (1 + ext4_bg_num_gdb(sb, group) +
35 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
36 ext4_fsblk_t metaend = start + overhead;
37 struct buffer_head *bh = NULL;
38 ext4_grpblk_t free_blocks_count, offset;
41 input->free_blocks_count = free_blocks_count =
42 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
44 if (test_opt(sb, DEBUG))
45 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
46 "(%d free, %u reserved)\n",
47 ext4_bg_has_super(sb, input->group) ? "normal" :
48 "no-super", input->group, input->blocks_count,
49 free_blocks_count, input->reserved_blocks);
51 ext4_get_group_no_and_offset(sb, start, NULL, &offset);
52 if (group != sbi->s_groups_count)
53 ext4_warning(sb, __FUNCTION__,
54 "Cannot add at group %u (only %lu groups)",
55 input->group, sbi->s_groups_count);
57 ext4_warning(sb, __FUNCTION__, "Last group not full");
58 else if (input->reserved_blocks > input->blocks_count / 5)
59 ext4_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
60 input->reserved_blocks);
61 else if (free_blocks_count < 0)
62 ext4_warning(sb, __FUNCTION__, "Bad blocks count %u",
64 else if (!(bh = sb_bread(sb, end - 1)))
65 ext4_warning(sb, __FUNCTION__,
66 "Cannot read last block (%llu)",
68 else if (outside(input->block_bitmap, start, end))
69 ext4_warning(sb, __FUNCTION__,
70 "Block bitmap not in group (block %llu)",
71 (unsigned long long)input->block_bitmap);
72 else if (outside(input->inode_bitmap, start, end))
73 ext4_warning(sb, __FUNCTION__,
74 "Inode bitmap not in group (block %llu)",
75 (unsigned long long)input->inode_bitmap);
76 else if (outside(input->inode_table, start, end) ||
77 outside(itend - 1, start, end))
78 ext4_warning(sb, __FUNCTION__,
79 "Inode table not in group (blocks %llu-%llu)",
80 (unsigned long long)input->inode_table, itend - 1);
81 else if (input->inode_bitmap == input->block_bitmap)
82 ext4_warning(sb, __FUNCTION__,
83 "Block bitmap same as inode bitmap (%llu)",
84 (unsigned long long)input->block_bitmap);
85 else if (inside(input->block_bitmap, input->inode_table, itend))
86 ext4_warning(sb, __FUNCTION__,
87 "Block bitmap (%llu) in inode table (%llu-%llu)",
88 (unsigned long long)input->block_bitmap,
89 (unsigned long long)input->inode_table, itend - 1);
90 else if (inside(input->inode_bitmap, input->inode_table, itend))
91 ext4_warning(sb, __FUNCTION__,
92 "Inode bitmap (%llu) in inode table (%llu-%llu)",
93 (unsigned long long)input->inode_bitmap,
94 (unsigned long long)input->inode_table, itend - 1);
95 else if (inside(input->block_bitmap, start, metaend))
96 ext4_warning(sb, __FUNCTION__,
97 "Block bitmap (%llu) in GDT table"
99 (unsigned long long)input->block_bitmap,
101 else if (inside(input->inode_bitmap, start, metaend))
102 ext4_warning(sb, __FUNCTION__,
103 "Inode bitmap (%llu) in GDT table"
105 (unsigned long long)input->inode_bitmap,
107 else if (inside(input->inode_table, start, metaend) ||
108 inside(itend - 1, start, metaend))
109 ext4_warning(sb, __FUNCTION__,
110 "Inode table (%llu-%llu) overlaps"
111 "GDT table (%llu-%llu)",
112 (unsigned long long)input->inode_table,
113 itend - 1, start, metaend - 1);
121 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
124 struct buffer_head *bh;
127 bh = sb_getblk(sb, blk);
129 return ERR_PTR(-EIO);
130 if ((err = ext4_journal_get_write_access(handle, bh))) {
135 memset(bh->b_data, 0, sb->s_blocksize);
136 set_buffer_uptodate(bh);
144 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
145 * If that fails, restart the transaction & regain write access for the
146 * buffer head which is used for block_bitmap modifications.
148 static int extend_or_restart_transaction(handle_t *handle, int thresh,
149 struct buffer_head *bh)
153 if (handle->h_buffer_credits >= thresh)
156 err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
160 if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
162 if ((err = ext4_journal_get_write_access(handle, bh)))
170 * Set up the block and inode bitmaps, and the inode table for the new group.
171 * This doesn't need to be part of the main transaction, since we are only
172 * changing blocks outside the actual filesystem. We still do journaling to
173 * ensure the recovery is correct in case of a failure just after resize.
174 * If any part of this fails, we simply abort the resize.
176 static int setup_new_group_blocks(struct super_block *sb,
177 struct ext4_new_group_data *input)
179 struct ext4_sb_info *sbi = EXT4_SB(sb);
180 ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group);
181 int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
182 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
183 unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group);
184 struct buffer_head *bh;
191 /* This transaction may be extended/restarted along the way */
192 handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
195 return PTR_ERR(handle);
198 if (input->group != sbi->s_groups_count) {
203 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
208 if (ext4_bg_has_super(sb, input->group)) {
209 ext4_debug("mark backup superblock %#04llx (+0)\n", start);
210 ext4_set_bit(0, bh->b_data);
213 /* Copy all of the GDT blocks into the backup in this group */
214 for (i = 0, bit = 1, block = start + 1;
215 i < gdblocks; i++, block++, bit++) {
216 struct buffer_head *gdb;
218 ext4_debug("update backup group %#04llx (+%d)\n", block, bit);
220 if ((err = extend_or_restart_transaction(handle, 1, bh)))
223 gdb = sb_getblk(sb, block);
228 if ((err = ext4_journal_get_write_access(handle, gdb))) {
233 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
234 set_buffer_uptodate(gdb);
236 ext4_journal_dirty_metadata(handle, gdb);
237 ext4_set_bit(bit, bh->b_data);
241 /* Zero out all of the reserved backup group descriptor table blocks */
242 for (i = 0, bit = gdblocks + 1, block = start + bit;
243 i < reserved_gdb; i++, block++, bit++) {
244 struct buffer_head *gdb;
246 ext4_debug("clear reserved block %#04llx (+%d)\n", block, bit);
248 if ((err = extend_or_restart_transaction(handle, 1, bh)))
251 if (IS_ERR(gdb = bclean(handle, sb, block))) {
255 ext4_journal_dirty_metadata(handle, gdb);
256 ext4_set_bit(bit, bh->b_data);
259 ext4_debug("mark block bitmap %#04llx (+%llu)\n", input->block_bitmap,
260 input->block_bitmap - start);
261 ext4_set_bit(input->block_bitmap - start, bh->b_data);
262 ext4_debug("mark inode bitmap %#04llx (+%llu)\n", input->inode_bitmap,
263 input->inode_bitmap - start);
264 ext4_set_bit(input->inode_bitmap - start, bh->b_data);
266 /* Zero out all of the inode table blocks */
267 for (i = 0, block = input->inode_table, bit = block - start;
268 i < sbi->s_itb_per_group; i++, bit++, block++) {
269 struct buffer_head *it;
271 ext4_debug("clear inode block %#04llx (+%d)\n", block, bit);
273 if ((err = extend_or_restart_transaction(handle, 1, bh)))
276 if (IS_ERR(it = bclean(handle, sb, block))) {
280 ext4_journal_dirty_metadata(handle, it);
282 ext4_set_bit(bit, bh->b_data);
285 if ((err = extend_or_restart_transaction(handle, 2, bh)))
288 mark_bitmap_end(input->blocks_count, EXT4_BLOCKS_PER_GROUP(sb),
290 ext4_journal_dirty_metadata(handle, bh);
293 /* Mark unused entries in inode bitmap used */
294 ext4_debug("clear inode bitmap %#04llx (+%llu)\n",
295 input->inode_bitmap, input->inode_bitmap - start);
296 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
301 mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), EXT4_BLOCKS_PER_GROUP(sb),
303 ext4_journal_dirty_metadata(handle, bh);
309 if ((err2 = ext4_journal_stop(handle)) && !err)
316 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
317 * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before
318 * calling this for the first time. In a sparse filesystem it will be the
319 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
320 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
322 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
323 unsigned *five, unsigned *seven)
325 unsigned *min = three;
329 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
330 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
352 * Check that all of the backup GDT blocks are held in the primary GDT block.
353 * It is assumed that they are stored in group order. Returns the number of
354 * groups in current filesystem that have BACKUPS, or -ve error code.
356 static int verify_reserved_gdb(struct super_block *sb,
357 struct buffer_head *primary)
359 const ext4_fsblk_t blk = primary->b_blocknr;
360 const ext4_group_t end = EXT4_SB(sb)->s_groups_count;
365 __le32 *p = (__le32 *)primary->b_data;
368 while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
369 if (le32_to_cpu(*p++) !=
370 grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
371 ext4_warning(sb, __FUNCTION__,
373 " missing grp %d (%llu)",
376 (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
380 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
388 * Called when we need to bring a reserved group descriptor table block into
389 * use from the resize inode. The primary copy of the new GDT block currently
390 * is an indirect block (under the double indirect block in the resize inode).
391 * The new backup GDT blocks will be stored as leaf blocks in this indirect
392 * block, in group order. Even though we know all the block numbers we need,
393 * we check to ensure that the resize inode has actually reserved these blocks.
395 * Don't need to update the block bitmaps because the blocks are still in use.
397 * We get all of the error cases out of the way, so that we are sure to not
398 * fail once we start modifying the data on disk, because JBD has no rollback.
400 static int add_new_gdb(handle_t *handle, struct inode *inode,
401 struct ext4_new_group_data *input,
402 struct buffer_head **primary)
404 struct super_block *sb = inode->i_sb;
405 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
406 unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
407 ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
408 struct buffer_head **o_group_desc, **n_group_desc;
409 struct buffer_head *dind;
411 struct ext4_iloc iloc;
415 if (test_opt(sb, DEBUG))
417 "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
421 * If we are not using the primary superblock/GDT copy don't resize,
422 * because the user tools have no way of handling this. Probably a
423 * bad time to do it anyways.
425 if (EXT4_SB(sb)->s_sbh->b_blocknr !=
426 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
427 ext4_warning(sb, __FUNCTION__,
428 "won't resize using backup superblock at %llu",
429 (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
433 *primary = sb_bread(sb, gdblock);
437 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
442 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
443 dind = sb_bread(sb, le32_to_cpu(*data));
449 data = (__le32 *)dind->b_data;
450 if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
451 ext4_warning(sb, __FUNCTION__,
452 "new group %u GDT block %llu not reserved",
453 input->group, gdblock);
458 if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh)))
461 if ((err = ext4_journal_get_write_access(handle, *primary)))
464 if ((err = ext4_journal_get_write_access(handle, dind)))
467 /* ext4_reserve_inode_write() gets a reference on the iloc */
468 if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
471 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
475 ext4_warning (sb, __FUNCTION__,
476 "not enough memory for %lu groups", gdb_num + 1);
481 * Finally, we have all of the possible failures behind us...
483 * Remove new GDT block from inode double-indirect block and clear out
484 * the new GDT block for use (which also "frees" the backup GDT blocks
485 * from the reserved inode). We don't need to change the bitmaps for
486 * these blocks, because they are marked as in-use from being in the
487 * reserved inode, and will become GDT blocks (primary and backup).
489 data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
490 ext4_journal_dirty_metadata(handle, dind);
492 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
493 ext4_mark_iloc_dirty(handle, inode, &iloc);
494 memset((*primary)->b_data, 0, sb->s_blocksize);
495 ext4_journal_dirty_metadata(handle, *primary);
497 o_group_desc = EXT4_SB(sb)->s_group_desc;
498 memcpy(n_group_desc, o_group_desc,
499 EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
500 n_group_desc[gdb_num] = *primary;
501 EXT4_SB(sb)->s_group_desc = n_group_desc;
502 EXT4_SB(sb)->s_gdb_count++;
505 le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
506 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
511 //ext4_journal_release_buffer(handle, iloc.bh);
514 //ext4_journal_release_buffer(handle, dind);
516 //ext4_journal_release_buffer(handle, *primary);
518 //ext4_journal_release_buffer(handle, *primary);
524 ext4_debug("leaving with error %d\n", err);
529 * Called when we are adding a new group which has a backup copy of each of
530 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
531 * We need to add these reserved backup GDT blocks to the resize inode, so
532 * that they are kept for future resizing and not allocated to files.
534 * Each reserved backup GDT block will go into a different indirect block.
535 * The indirect blocks are actually the primary reserved GDT blocks,
536 * so we know in advance what their block numbers are. We only get the
537 * double-indirect block to verify it is pointing to the primary reserved
538 * GDT blocks so we don't overwrite a data block by accident. The reserved
539 * backup GDT blocks are stored in their reserved primary GDT block.
541 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
542 struct ext4_new_group_data *input)
544 struct super_block *sb = inode->i_sb;
545 int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
546 struct buffer_head **primary;
547 struct buffer_head *dind;
548 struct ext4_iloc iloc;
555 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
559 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
560 dind = sb_bread(sb, le32_to_cpu(*data));
566 blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
567 data = (__le32 *)dind->b_data + EXT4_SB(sb)->s_gdb_count;
568 end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
570 /* Get each reserved primary GDT block and verify it holds backups */
571 for (res = 0; res < reserved_gdb; res++, blk++) {
572 if (le32_to_cpu(*data) != blk) {
573 ext4_warning(sb, __FUNCTION__,
574 "reserved block %llu"
575 " not at offset %ld",
577 (long)(data - (__le32 *)dind->b_data));
581 primary[res] = sb_bread(sb, blk);
586 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
587 brelse(primary[res]);
592 data = (__le32 *)dind->b_data;
595 for (i = 0; i < reserved_gdb; i++) {
596 if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
599 for (j = 0; j < i; j++)
600 ext4_journal_release_buffer(handle, primary[j]);
606 if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
610 * Finally we can add each of the reserved backup GDT blocks from
611 * the new group to its reserved primary GDT block.
613 blk = input->group * EXT4_BLOCKS_PER_GROUP(sb);
614 for (i = 0; i < reserved_gdb; i++) {
616 data = (__le32 *)primary[i]->b_data;
617 /* printk("reserving backup %lu[%u] = %lu\n",
618 primary[i]->b_blocknr, gdbackups,
619 blk + primary[i]->b_blocknr); */
620 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
621 err2 = ext4_journal_dirty_metadata(handle, primary[i]);
625 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
626 ext4_mark_iloc_dirty(handle, inode, &iloc);
630 brelse(primary[res]);
640 * Update the backup copies of the ext4 metadata. These don't need to be part
641 * of the main resize transaction, because e2fsck will re-write them if there
642 * is a problem (basically only OOM will cause a problem). However, we
643 * _should_ update the backups if possible, in case the primary gets trashed
644 * for some reason and we need to run e2fsck from a backup superblock. The
645 * important part is that the new block and inode counts are in the backup
646 * superblocks, and the location of the new group metadata in the GDT backups.
648 * We do not need lock_super() for this, because these blocks are not
649 * otherwise touched by the filesystem code when it is mounted. We don't
650 * need to worry about last changing from sbi->s_groups_count, because the
651 * worst that can happen is that we do not copy the full number of backups
652 * at this time. The resize which changed s_groups_count will backup again.
654 static void update_backups(struct super_block *sb,
655 int blk_off, char *data, int size)
657 struct ext4_sb_info *sbi = EXT4_SB(sb);
658 const ext4_group_t last = sbi->s_groups_count;
659 const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
664 int rest = sb->s_blocksize - size;
668 handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
669 if (IS_ERR(handle)) {
671 err = PTR_ERR(handle);
675 while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
676 struct buffer_head *bh;
678 /* Out of journal space, and can't get more - abort - so sad */
679 if (handle->h_buffer_credits == 0 &&
680 ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
681 (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
684 bh = sb_getblk(sb, group * bpg + blk_off);
689 ext4_debug("update metadata backup %#04lx\n",
690 (unsigned long)bh->b_blocknr);
691 if ((err = ext4_journal_get_write_access(handle, bh)))
694 memcpy(bh->b_data, data, size);
696 memset(bh->b_data + size, 0, rest);
697 set_buffer_uptodate(bh);
699 ext4_journal_dirty_metadata(handle, bh);
702 if ((err2 = ext4_journal_stop(handle)) && !err)
706 * Ugh! Need to have e2fsck write the backup copies. It is too
707 * late to revert the resize, we shouldn't fail just because of
708 * the backup copies (they are only needed in case of corruption).
710 * However, if we got here we have a journal problem too, so we
711 * can't really start a transaction to mark the superblock.
712 * Chicken out and just set the flag on the hope it will be written
713 * to disk, and if not - we will simply wait until next fsck.
717 ext4_warning(sb, __FUNCTION__,
718 "can't update backup for group %lu (err %d), "
719 "forcing fsck on next reboot", group, err);
720 sbi->s_mount_state &= ~EXT4_VALID_FS;
721 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
722 mark_buffer_dirty(sbi->s_sbh);
726 /* Add group descriptor data to an existing or new group descriptor block.
727 * Ensure we handle all possible error conditions _before_ we start modifying
728 * the filesystem, because we cannot abort the transaction and not have it
729 * write the data to disk.
731 * If we are on a GDT block boundary, we need to get the reserved GDT block.
732 * Otherwise, we may need to add backup GDT blocks for a sparse group.
734 * We only need to hold the superblock lock while we are actually adding
735 * in the new group's counts to the superblock. Prior to that we have
736 * not really "added" the group at all. We re-check that we are still
737 * adding in the last group in case things have changed since verifying.
739 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
741 struct ext4_sb_info *sbi = EXT4_SB(sb);
742 struct ext4_super_block *es = sbi->s_es;
743 int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
744 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
745 struct buffer_head *primary = NULL;
746 struct ext4_group_desc *gdp;
747 struct inode *inode = NULL;
749 int gdb_off, gdb_num;
752 gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
753 gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
755 if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
756 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
757 ext4_warning(sb, __FUNCTION__,
758 "Can't resize non-sparse filesystem further");
762 if (ext4_blocks_count(es) + input->blocks_count <
763 ext4_blocks_count(es)) {
764 ext4_warning(sb, __FUNCTION__, "blocks_count overflow\n");
768 if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
769 le32_to_cpu(es->s_inodes_count)) {
770 ext4_warning(sb, __FUNCTION__, "inodes_count overflow\n");
774 if (reserved_gdb || gdb_off == 0) {
775 if (!EXT4_HAS_COMPAT_FEATURE(sb,
776 EXT4_FEATURE_COMPAT_RESIZE_INODE)){
777 ext4_warning(sb, __FUNCTION__,
778 "No reserved GDT blocks, can't resize");
781 inode = ext4_iget(sb, EXT4_RESIZE_INO);
783 ext4_warning(sb, __FUNCTION__,
784 "Error opening resize inode");
785 return PTR_ERR(inode);
789 if ((err = verify_group_input(sb, input)))
792 if ((err = setup_new_group_blocks(sb, input)))
796 * We will always be modifying at least the superblock and a GDT
797 * block. If we are adding a group past the last current GDT block,
798 * we will also modify the inode and the dindirect block. If we
799 * are adding a group with superblock/GDT backups we will also
800 * modify each of the reserved GDT dindirect blocks.
802 handle = ext4_journal_start_sb(sb,
803 ext4_bg_has_super(sb, input->group) ?
804 3 + reserved_gdb : 4);
805 if (IS_ERR(handle)) {
806 err = PTR_ERR(handle);
811 if (input->group != sbi->s_groups_count) {
812 ext4_warning(sb, __FUNCTION__,
813 "multiple resizers run on filesystem!");
818 if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh)))
822 * We will only either add reserved group blocks to a backup group
823 * or remove reserved blocks for the first group in a new group block.
824 * Doing both would be mean more complex code, and sane people don't
825 * use non-sparse filesystems anymore. This is already checked above.
828 primary = sbi->s_group_desc[gdb_num];
829 if ((err = ext4_journal_get_write_access(handle, primary)))
832 if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) &&
833 (err = reserve_backup_gdb(handle, inode, input)))
835 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
839 * OK, now we've set up the new group. Time to make it active.
841 * Current kernels don't lock all allocations via lock_super(),
842 * so we have to be safe wrt. concurrent accesses the group
843 * data. So we need to be careful to set all of the relevant
844 * group descriptor data etc. *before* we enable the group.
846 * The key field here is sbi->s_groups_count: as long as
847 * that retains its old value, nobody is going to access the new
850 * So first we update all the descriptor metadata for the new
851 * group; then we update the total disk blocks count; then we
852 * update the groups count to enable the group; then finally we
853 * update the free space counts so that the system can start
854 * using the new disk blocks.
857 /* Update group descriptor block for new group */
858 gdp = (struct ext4_group_desc *)primary->b_data + gdb_off;
860 ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */
861 ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */
862 ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
863 gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
864 gdp->bg_free_inodes_count = cpu_to_le16(EXT4_INODES_PER_GROUP(sb));
865 gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
868 * Make the new blocks and inodes valid next. We do this before
869 * increasing the group count so that once the group is enabled,
870 * all of its blocks and inodes are already valid.
872 * We always allocate group-by-group, then block-by-block or
873 * inode-by-inode within a group, so enabling these
874 * blocks/inodes before the group is live won't actually let us
875 * allocate the new space yet.
877 ext4_blocks_count_set(es, ext4_blocks_count(es) +
878 input->blocks_count);
879 le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb));
882 * We need to protect s_groups_count against other CPUs seeing
883 * inconsistent state in the superblock.
885 * The precise rules we use are:
887 * * Writers of s_groups_count *must* hold lock_super
889 * * Writers must perform a smp_wmb() after updating all dependent
890 * data and before modifying the groups count
892 * * Readers must hold lock_super() over the access
894 * * Readers must perform an smp_rmb() after reading the groups count
895 * and before reading any dependent data.
897 * NB. These rules can be relaxed when checking the group count
898 * while freeing data, as we can only allocate from a block
899 * group after serialising against the group count, and we can
900 * only then free after serialising in turn against that
905 /* Update the global fs size fields */
906 sbi->s_groups_count++;
908 ext4_journal_dirty_metadata(handle, primary);
910 /* Update the reserved block counts only once the new group is
912 ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
913 input->reserved_blocks);
915 /* Update the free space counts */
916 percpu_counter_add(&sbi->s_freeblocks_counter,
917 input->free_blocks_count);
918 percpu_counter_add(&sbi->s_freeinodes_counter,
919 EXT4_INODES_PER_GROUP(sb));
921 ext4_journal_dirty_metadata(handle, sbi->s_sbh);
926 if ((err2 = ext4_journal_stop(handle)) && !err)
929 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
930 sizeof(struct ext4_super_block));
931 update_backups(sb, primary->b_blocknr, primary->b_data,
937 } /* ext4_group_add */
939 /* Extend the filesystem to the new number of blocks specified. This entry
940 * point is only used to extend the current filesystem to the end of the last
941 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
942 * for emergencies (because it has no dependencies on reserved blocks).
944 * If we _really_ wanted, we could use default values to call ext4_group_add()
945 * allow the "remount" trick to work for arbitrary resizing, assuming enough
946 * GDT blocks are reserved to grow to the desired size.
948 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
949 ext4_fsblk_t n_blocks_count)
951 ext4_fsblk_t o_blocks_count;
952 ext4_group_t o_groups_count;
955 struct buffer_head * bh;
958 unsigned long freed_blocks;
960 /* We don't need to worry about locking wrt other resizers just
961 * yet: we're going to revalidate es->s_blocks_count after
962 * taking lock_super() below. */
963 o_blocks_count = ext4_blocks_count(es);
964 o_groups_count = EXT4_SB(sb)->s_groups_count;
966 if (test_opt(sb, DEBUG))
967 printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n",
968 o_blocks_count, n_blocks_count);
970 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
973 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
974 printk(KERN_ERR "EXT4-fs: filesystem on %s:"
975 " too large to resize to %llu blocks safely\n",
976 sb->s_id, n_blocks_count);
977 if (sizeof(sector_t) < 8)
978 ext4_warning(sb, __FUNCTION__,
979 "CONFIG_LBD not enabled\n");
983 if (n_blocks_count < o_blocks_count) {
984 ext4_warning(sb, __FUNCTION__,
985 "can't shrink FS - resize aborted");
989 /* Handle the remaining blocks in the last group only. */
990 ext4_get_group_no_and_offset(sb, o_blocks_count, NULL, &last);
993 ext4_warning(sb, __FUNCTION__,
994 "need to use ext2online to resize further");
998 add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1000 if (o_blocks_count + add < o_blocks_count) {
1001 ext4_warning(sb, __FUNCTION__, "blocks_count overflow");
1005 if (o_blocks_count + add > n_blocks_count)
1006 add = n_blocks_count - o_blocks_count;
1008 if (o_blocks_count + add < n_blocks_count)
1009 ext4_warning(sb, __FUNCTION__,
1010 "will only finish group (%llu"
1012 o_blocks_count + add, add);
1014 /* See if the device is actually as big as what was requested */
1015 bh = sb_bread(sb, o_blocks_count + add -1);
1017 ext4_warning(sb, __FUNCTION__,
1018 "can't read last block, resize aborted");
1023 /* We will update the superblock, one block bitmap, and
1024 * one group descriptor via ext4_free_blocks().
1026 handle = ext4_journal_start_sb(sb, 3);
1027 if (IS_ERR(handle)) {
1028 err = PTR_ERR(handle);
1029 ext4_warning(sb, __FUNCTION__, "error %d on journal start",err);
1034 if (o_blocks_count != ext4_blocks_count(es)) {
1035 ext4_warning(sb, __FUNCTION__,
1036 "multiple resizers run on filesystem!");
1038 ext4_journal_stop(handle);
1043 if ((err = ext4_journal_get_write_access(handle,
1044 EXT4_SB(sb)->s_sbh))) {
1045 ext4_warning(sb, __FUNCTION__,
1046 "error %d on journal write access", err);
1048 ext4_journal_stop(handle);
1051 ext4_blocks_count_set(es, o_blocks_count + add);
1052 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
1055 ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1056 o_blocks_count + add);
1057 ext4_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
1058 ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1059 o_blocks_count + add);
1060 if ((err = ext4_journal_stop(handle)))
1062 if (test_opt(sb, DEBUG))
1063 printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
1064 ext4_blocks_count(es));
1065 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1066 sizeof(struct ext4_super_block));
1069 } /* ext4_group_extend */