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/errno.h>
15 #include <linux/slab.h>
17 #include "ext4_jbd2.h"
19 int ext4_resize_begin(struct super_block *sb)
23 if (!capable(CAP_SYS_RESOURCE))
26 if (test_and_set_bit_lock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags))
32 void ext4_resize_end(struct super_block *sb)
34 clear_bit_unlock(EXT4_RESIZING, &EXT4_SB(sb)->s_resize_flags);
35 smp_mb__after_clear_bit();
38 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
39 #define inside(b, first, last) ((b) >= (first) && (b) < (last))
41 static int verify_group_input(struct super_block *sb,
42 struct ext4_new_group_data *input)
44 struct ext4_sb_info *sbi = EXT4_SB(sb);
45 struct ext4_super_block *es = sbi->s_es;
46 ext4_fsblk_t start = ext4_blocks_count(es);
47 ext4_fsblk_t end = start + input->blocks_count;
48 ext4_group_t group = input->group;
49 ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
50 unsigned overhead = ext4_bg_has_super(sb, group) ?
51 (1 + ext4_bg_num_gdb(sb, group) +
52 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
53 ext4_fsblk_t metaend = start + overhead;
54 struct buffer_head *bh = NULL;
55 ext4_grpblk_t free_blocks_count, offset;
58 input->free_blocks_count = free_blocks_count =
59 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
61 if (test_opt(sb, DEBUG))
62 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
63 "(%d free, %u reserved)\n",
64 ext4_bg_has_super(sb, input->group) ? "normal" :
65 "no-super", input->group, input->blocks_count,
66 free_blocks_count, input->reserved_blocks);
68 ext4_get_group_no_and_offset(sb, start, NULL, &offset);
69 if (group != sbi->s_groups_count)
70 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
71 input->group, sbi->s_groups_count);
73 ext4_warning(sb, "Last group not full");
74 else if (input->reserved_blocks > input->blocks_count / 5)
75 ext4_warning(sb, "Reserved blocks too high (%u)",
76 input->reserved_blocks);
77 else if (free_blocks_count < 0)
78 ext4_warning(sb, "Bad blocks count %u",
80 else if (!(bh = sb_bread(sb, end - 1)))
81 ext4_warning(sb, "Cannot read last block (%llu)",
83 else if (outside(input->block_bitmap, start, end))
84 ext4_warning(sb, "Block bitmap not in group (block %llu)",
85 (unsigned long long)input->block_bitmap);
86 else if (outside(input->inode_bitmap, start, end))
87 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
88 (unsigned long long)input->inode_bitmap);
89 else if (outside(input->inode_table, start, end) ||
90 outside(itend - 1, start, end))
91 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
92 (unsigned long long)input->inode_table, itend - 1);
93 else if (input->inode_bitmap == input->block_bitmap)
94 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
95 (unsigned long long)input->block_bitmap);
96 else if (inside(input->block_bitmap, input->inode_table, itend))
97 ext4_warning(sb, "Block bitmap (%llu) in inode table "
99 (unsigned long long)input->block_bitmap,
100 (unsigned long long)input->inode_table, itend - 1);
101 else if (inside(input->inode_bitmap, input->inode_table, itend))
102 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
104 (unsigned long long)input->inode_bitmap,
105 (unsigned long long)input->inode_table, itend - 1);
106 else if (inside(input->block_bitmap, start, metaend))
107 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
108 (unsigned long long)input->block_bitmap,
110 else if (inside(input->inode_bitmap, start, metaend))
111 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
112 (unsigned long long)input->inode_bitmap,
114 else if (inside(input->inode_table, start, metaend) ||
115 inside(itend - 1, start, metaend))
116 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
118 (unsigned long long)input->inode_table,
119 itend - 1, start, metaend - 1);
127 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
130 struct buffer_head *bh;
133 bh = sb_getblk(sb, blk);
135 return ERR_PTR(-EIO);
136 if ((err = ext4_journal_get_write_access(handle, bh))) {
141 memset(bh->b_data, 0, sb->s_blocksize);
142 set_buffer_uptodate(bh);
150 * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA.
151 * If that fails, restart the transaction & regain write access for the
152 * buffer head which is used for block_bitmap modifications.
154 static int extend_or_restart_transaction(handle_t *handle, int thresh,
155 struct buffer_head *bh)
159 if (ext4_handle_has_enough_credits(handle, thresh))
162 err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA);
166 if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
168 if ((err = ext4_journal_get_write_access(handle, bh)))
176 * Set up the block and inode bitmaps, and the inode table for the new group.
177 * This doesn't need to be part of the main transaction, since we are only
178 * changing blocks outside the actual filesystem. We still do journaling to
179 * ensure the recovery is correct in case of a failure just after resize.
180 * If any part of this fails, we simply abort the resize.
182 static int setup_new_group_blocks(struct super_block *sb,
183 struct ext4_new_group_data *input)
185 struct ext4_sb_info *sbi = EXT4_SB(sb);
186 ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group);
187 int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
188 le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
189 unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group);
190 struct buffer_head *bh;
197 /* This transaction may be extended/restarted along the way */
198 handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
201 return PTR_ERR(handle);
203 BUG_ON(input->group != sbi->s_groups_count);
205 if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
210 if (ext4_bg_has_super(sb, input->group)) {
211 ext4_debug("mark backup superblock %#04llx (+0)\n", start);
212 ext4_set_bit(0, bh->b_data);
215 /* Copy all of the GDT blocks into the backup in this group */
216 for (i = 0, bit = 1, block = start + 1;
217 i < gdblocks; i++, block++, bit++) {
218 struct buffer_head *gdb;
220 ext4_debug("update backup group %#04llx (+%d)\n", block, bit);
222 if ((err = extend_or_restart_transaction(handle, 1, bh)))
225 gdb = sb_getblk(sb, block);
230 if ((err = ext4_journal_get_write_access(handle, gdb))) {
235 memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size);
236 set_buffer_uptodate(gdb);
238 err = ext4_handle_dirty_metadata(handle, NULL, gdb);
243 ext4_set_bit(bit, bh->b_data);
247 /* Zero out all of the reserved backup group descriptor table blocks */
248 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
249 block, sbi->s_itb_per_group);
250 err = sb_issue_zeroout(sb, gdblocks + start + 1, reserved_gdb,
254 for (i = 0, bit = gdblocks + 1; i < reserved_gdb; i++, bit++)
255 ext4_set_bit(bit, bh->b_data);
257 ext4_debug("mark block bitmap %#04llx (+%llu)\n", input->block_bitmap,
258 input->block_bitmap - start);
259 ext4_set_bit(input->block_bitmap - start, bh->b_data);
260 ext4_debug("mark inode bitmap %#04llx (+%llu)\n", input->inode_bitmap,
261 input->inode_bitmap - start);
262 ext4_set_bit(input->inode_bitmap - start, bh->b_data);
264 /* Zero out all of the inode table blocks */
265 block = input->inode_table;
266 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
267 block, sbi->s_itb_per_group);
268 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group, GFP_NOFS);
271 for (i = 0, bit = input->inode_table - start;
272 i < sbi->s_itb_per_group; i++, bit++)
273 ext4_set_bit(bit, bh->b_data);
275 if ((err = extend_or_restart_transaction(handle, 2, bh)))
278 ext4_mark_bitmap_end(input->blocks_count, sb->s_blocksize * 8,
280 err = ext4_handle_dirty_metadata(handle, NULL, bh);
282 ext4_std_error(sb, err);
286 /* Mark unused entries in inode bitmap used */
287 ext4_debug("clear inode bitmap %#04llx (+%llu)\n",
288 input->inode_bitmap, input->inode_bitmap - start);
289 if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
294 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
296 err = ext4_handle_dirty_metadata(handle, NULL, bh);
298 ext4_std_error(sb, err);
303 if ((err2 = ext4_journal_stop(handle)) && !err)
310 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
311 * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before
312 * calling this for the first time. In a sparse filesystem it will be the
313 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
314 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
316 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
317 unsigned *five, unsigned *seven)
319 unsigned *min = three;
323 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
324 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
346 * Check that all of the backup GDT blocks are held in the primary GDT block.
347 * It is assumed that they are stored in group order. Returns the number of
348 * groups in current filesystem that have BACKUPS, or -ve error code.
350 static int verify_reserved_gdb(struct super_block *sb,
351 struct buffer_head *primary)
353 const ext4_fsblk_t blk = primary->b_blocknr;
354 const ext4_group_t end = EXT4_SB(sb)->s_groups_count;
359 __le32 *p = (__le32 *)primary->b_data;
362 while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
363 if (le32_to_cpu(*p++) !=
364 grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
365 ext4_warning(sb, "reserved GDT %llu"
366 " missing grp %d (%llu)",
369 (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
373 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
381 * Called when we need to bring a reserved group descriptor table block into
382 * use from the resize inode. The primary copy of the new GDT block currently
383 * is an indirect block (under the double indirect block in the resize inode).
384 * The new backup GDT blocks will be stored as leaf blocks in this indirect
385 * block, in group order. Even though we know all the block numbers we need,
386 * we check to ensure that the resize inode has actually reserved these blocks.
388 * Don't need to update the block bitmaps because the blocks are still in use.
390 * We get all of the error cases out of the way, so that we are sure to not
391 * fail once we start modifying the data on disk, because JBD has no rollback.
393 static int add_new_gdb(handle_t *handle, struct inode *inode,
394 struct ext4_new_group_data *input,
395 struct buffer_head **primary)
397 struct super_block *sb = inode->i_sb;
398 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
399 unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
400 ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
401 struct buffer_head **o_group_desc, **n_group_desc;
402 struct buffer_head *dind;
404 struct ext4_iloc iloc;
408 if (test_opt(sb, DEBUG))
410 "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
414 * If we are not using the primary superblock/GDT copy don't resize,
415 * because the user tools have no way of handling this. Probably a
416 * bad time to do it anyways.
418 if (EXT4_SB(sb)->s_sbh->b_blocknr !=
419 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
420 ext4_warning(sb, "won't resize using backup superblock at %llu",
421 (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
425 *primary = sb_bread(sb, gdblock);
429 if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
434 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
435 dind = sb_bread(sb, le32_to_cpu(*data));
441 data = (__le32 *)dind->b_data;
442 if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
443 ext4_warning(sb, "new group %u GDT block %llu not reserved",
444 input->group, gdblock);
449 err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
453 err = ext4_journal_get_write_access(handle, *primary);
457 err = ext4_journal_get_write_access(handle, dind);
459 ext4_std_error(sb, err);
461 /* ext4_reserve_inode_write() gets a reference on the iloc */
462 err = ext4_reserve_inode_write(handle, inode, &iloc);
466 n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
471 "not enough memory for %lu groups", gdb_num + 1);
476 * Finally, we have all of the possible failures behind us...
478 * Remove new GDT block from inode double-indirect block and clear out
479 * the new GDT block for use (which also "frees" the backup GDT blocks
480 * from the reserved inode). We don't need to change the bitmaps for
481 * these blocks, because they are marked as in-use from being in the
482 * reserved inode, and will become GDT blocks (primary and backup).
484 data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
485 err = ext4_handle_dirty_metadata(handle, NULL, dind);
487 ext4_std_error(sb, err);
490 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
491 ext4_mark_iloc_dirty(handle, inode, &iloc);
492 memset((*primary)->b_data, 0, sb->s_blocksize);
493 err = ext4_handle_dirty_metadata(handle, NULL, *primary);
495 ext4_std_error(sb, err);
500 o_group_desc = EXT4_SB(sb)->s_group_desc;
501 memcpy(n_group_desc, o_group_desc,
502 EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
503 n_group_desc[gdb_num] = *primary;
504 EXT4_SB(sb)->s_group_desc = n_group_desc;
505 EXT4_SB(sb)->s_gdb_count++;
508 le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
509 err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
511 ext4_std_error(sb, err);
516 /* ext4_handle_release_buffer(handle, iloc.bh); */
519 /* ext4_handle_release_buffer(handle, dind); */
521 /* ext4_handle_release_buffer(handle, EXT4_SB(sb)->s_sbh); */
527 ext4_debug("leaving with error %d\n", err);
532 * Called when we are adding a new group which has a backup copy of each of
533 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
534 * We need to add these reserved backup GDT blocks to the resize inode, so
535 * that they are kept for future resizing and not allocated to files.
537 * Each reserved backup GDT block will go into a different indirect block.
538 * The indirect blocks are actually the primary reserved GDT blocks,
539 * so we know in advance what their block numbers are. We only get the
540 * double-indirect block to verify it is pointing to the primary reserved
541 * GDT blocks so we don't overwrite a data block by accident. The reserved
542 * backup GDT blocks are stored in their reserved primary GDT block.
544 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
545 struct ext4_new_group_data *input)
547 struct super_block *sb = inode->i_sb;
548 int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
549 struct buffer_head **primary;
550 struct buffer_head *dind;
551 struct ext4_iloc iloc;
558 primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS);
562 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
563 dind = sb_bread(sb, le32_to_cpu(*data));
569 blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
570 data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
571 EXT4_ADDR_PER_BLOCK(sb));
572 end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
574 /* Get each reserved primary GDT block and verify it holds backups */
575 for (res = 0; res < reserved_gdb; res++, blk++) {
576 if (le32_to_cpu(*data) != blk) {
577 ext4_warning(sb, "reserved block %llu"
578 " not at offset %ld",
580 (long)(data - (__le32 *)dind->b_data));
584 primary[res] = sb_bread(sb, blk);
589 if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
590 brelse(primary[res]);
595 data = (__le32 *)dind->b_data;
598 for (i = 0; i < reserved_gdb; i++) {
599 if ((err = ext4_journal_get_write_access(handle, primary[i]))) {
602 for (j = 0; j < i; j++)
603 ext4_handle_release_buffer(handle, primary[j]);
609 if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
613 * Finally we can add each of the reserved backup GDT blocks from
614 * the new group to its reserved primary GDT block.
616 blk = input->group * EXT4_BLOCKS_PER_GROUP(sb);
617 for (i = 0; i < reserved_gdb; i++) {
619 data = (__le32 *)primary[i]->b_data;
620 /* printk("reserving backup %lu[%u] = %lu\n",
621 primary[i]->b_blocknr, gdbackups,
622 blk + primary[i]->b_blocknr); */
623 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
624 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
628 inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
629 ext4_mark_iloc_dirty(handle, inode, &iloc);
633 brelse(primary[res]);
643 * Update the backup copies of the ext4 metadata. These don't need to be part
644 * of the main resize transaction, because e2fsck will re-write them if there
645 * is a problem (basically only OOM will cause a problem). However, we
646 * _should_ update the backups if possible, in case the primary gets trashed
647 * for some reason and we need to run e2fsck from a backup superblock. The
648 * important part is that the new block and inode counts are in the backup
649 * superblocks, and the location of the new group metadata in the GDT backups.
651 * We do not need take the s_resize_lock for this, because these
652 * blocks are not otherwise touched by the filesystem code when it is
653 * mounted. We don't need to worry about last changing from
654 * sbi->s_groups_count, because the worst that can happen is that we
655 * do not copy the full number of backups at this time. The resize
656 * which changed s_groups_count will backup again.
658 static void update_backups(struct super_block *sb,
659 int blk_off, char *data, int size)
661 struct ext4_sb_info *sbi = EXT4_SB(sb);
662 const ext4_group_t last = sbi->s_groups_count;
663 const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
668 int rest = sb->s_blocksize - size;
672 handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA);
673 if (IS_ERR(handle)) {
675 err = PTR_ERR(handle);
679 while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
680 struct buffer_head *bh;
682 /* Out of journal space, and can't get more - abort - so sad */
683 if (ext4_handle_valid(handle) &&
684 handle->h_buffer_credits == 0 &&
685 ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) &&
686 (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
689 bh = sb_getblk(sb, group * bpg + blk_off);
694 ext4_debug("update metadata backup %#04lx\n",
695 (unsigned long)bh->b_blocknr);
696 if ((err = ext4_journal_get_write_access(handle, bh)))
699 memcpy(bh->b_data, data, size);
701 memset(bh->b_data + size, 0, rest);
702 set_buffer_uptodate(bh);
704 err = ext4_handle_dirty_metadata(handle, NULL, bh);
706 ext4_std_error(sb, err);
709 if ((err2 = ext4_journal_stop(handle)) && !err)
713 * Ugh! Need to have e2fsck write the backup copies. It is too
714 * late to revert the resize, we shouldn't fail just because of
715 * the backup copies (they are only needed in case of corruption).
717 * However, if we got here we have a journal problem too, so we
718 * can't really start a transaction to mark the superblock.
719 * Chicken out and just set the flag on the hope it will be written
720 * to disk, and if not - we will simply wait until next fsck.
724 ext4_warning(sb, "can't update backup for group %u (err %d), "
725 "forcing fsck on next reboot", group, err);
726 sbi->s_mount_state &= ~EXT4_VALID_FS;
727 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
728 mark_buffer_dirty(sbi->s_sbh);
732 /* Add group descriptor data to an existing or new group descriptor block.
733 * Ensure we handle all possible error conditions _before_ we start modifying
734 * the filesystem, because we cannot abort the transaction and not have it
735 * write the data to disk.
737 * If we are on a GDT block boundary, we need to get the reserved GDT block.
738 * Otherwise, we may need to add backup GDT blocks for a sparse group.
740 * We only need to hold the superblock lock while we are actually adding
741 * in the new group's counts to the superblock. Prior to that we have
742 * not really "added" the group at all. We re-check that we are still
743 * adding in the last group in case things have changed since verifying.
745 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
747 struct ext4_sb_info *sbi = EXT4_SB(sb);
748 struct ext4_super_block *es = sbi->s_es;
749 int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
750 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
751 struct buffer_head *primary = NULL;
752 struct ext4_group_desc *gdp;
753 struct inode *inode = NULL;
755 int gdb_off, gdb_num;
758 gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb);
759 gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
761 if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
762 EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
763 ext4_warning(sb, "Can't resize non-sparse filesystem further");
767 if (ext4_blocks_count(es) + input->blocks_count <
768 ext4_blocks_count(es)) {
769 ext4_warning(sb, "blocks_count overflow");
773 if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
774 le32_to_cpu(es->s_inodes_count)) {
775 ext4_warning(sb, "inodes_count overflow");
779 if (reserved_gdb || gdb_off == 0) {
780 if (!EXT4_HAS_COMPAT_FEATURE(sb,
781 EXT4_FEATURE_COMPAT_RESIZE_INODE)
782 || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
784 "No reserved GDT blocks, can't resize");
787 inode = ext4_iget(sb, EXT4_RESIZE_INO);
789 ext4_warning(sb, "Error opening resize inode");
790 return PTR_ERR(inode);
795 if ((err = verify_group_input(sb, input)))
798 if ((err = setup_new_group_blocks(sb, input)))
802 * We will always be modifying at least the superblock and a GDT
803 * block. If we are adding a group past the last current GDT block,
804 * we will also modify the inode and the dindirect block. If we
805 * are adding a group with superblock/GDT backups we will also
806 * modify each of the reserved GDT dindirect blocks.
808 handle = ext4_journal_start_sb(sb,
809 ext4_bg_has_super(sb, input->group) ?
810 3 + reserved_gdb : 4);
811 if (IS_ERR(handle)) {
812 err = PTR_ERR(handle);
816 if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh)))
820 * We will only either add reserved group blocks to a backup group
821 * or remove reserved blocks for the first group in a new group block.
822 * Doing both would be mean more complex code, and sane people don't
823 * use non-sparse filesystems anymore. This is already checked above.
826 primary = sbi->s_group_desc[gdb_num];
827 if ((err = ext4_journal_get_write_access(handle, primary)))
830 if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) &&
831 (err = reserve_backup_gdb(handle, inode, input)))
833 } else if ((err = add_new_gdb(handle, inode, input, &primary)))
837 * OK, now we've set up the new group. Time to make it active.
839 * so we have to be safe wrt. concurrent accesses the group
840 * data. So we need to be careful to set all of the relevant
841 * group descriptor data etc. *before* we enable the group.
843 * The key field here is sbi->s_groups_count: as long as
844 * that retains its old value, nobody is going to access the new
847 * So first we update all the descriptor metadata for the new
848 * group; then we update the total disk blocks count; then we
849 * update the groups count to enable the group; then finally we
850 * update the free space counts so that the system can start
851 * using the new disk blocks.
854 /* Update group descriptor block for new group */
855 gdp = (struct ext4_group_desc *)((char *)primary->b_data +
856 gdb_off * EXT4_DESC_SIZE(sb));
858 memset(gdp, 0, EXT4_DESC_SIZE(sb));
859 ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */
860 ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */
861 ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */
862 ext4_free_blks_set(sb, gdp, input->free_blocks_count);
863 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
864 gdp->bg_flags = cpu_to_le16(EXT4_BG_INODE_ZEROED);
865 gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
868 * We can allocate memory for mb_alloc based on the new group
871 err = ext4_mb_add_groupinfo(sb, input->group, gdp);
876 * Make the new blocks and inodes valid next. We do this before
877 * increasing the group count so that once the group is enabled,
878 * all of its blocks and inodes are already valid.
880 * We always allocate group-by-group, then block-by-block or
881 * inode-by-inode within a group, so enabling these
882 * blocks/inodes before the group is live won't actually let us
883 * allocate the new space yet.
885 ext4_blocks_count_set(es, ext4_blocks_count(es) +
886 input->blocks_count);
887 le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb));
890 * We need to protect s_groups_count against other CPUs seeing
891 * inconsistent state in the superblock.
893 * The precise rules we use are:
895 * * Writers must perform a smp_wmb() after updating all dependent
896 * data and before modifying the groups count
898 * * Readers must perform an smp_rmb() after reading the groups count
899 * and before reading any dependent data.
901 * NB. These rules can be relaxed when checking the group count
902 * while freeing data, as we can only allocate from a block
903 * group after serialising against the group count, and we can
904 * only then free after serialising in turn against that
909 /* Update the global fs size fields */
910 sbi->s_groups_count++;
912 err = ext4_handle_dirty_metadata(handle, NULL, primary);
914 ext4_std_error(sb, err);
918 /* Update the reserved block counts only once the new group is
920 ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
921 input->reserved_blocks);
923 /* Update the free space counts */
924 percpu_counter_add(&sbi->s_freeblocks_counter,
925 input->free_blocks_count);
926 percpu_counter_add(&sbi->s_freeinodes_counter,
927 EXT4_INODES_PER_GROUP(sb));
929 if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
930 sbi->s_log_groups_per_flex) {
931 ext4_group_t flex_group;
932 flex_group = ext4_flex_group(sbi, input->group);
933 atomic_add(input->free_blocks_count,
934 &sbi->s_flex_groups[flex_group].free_blocks);
935 atomic_add(EXT4_INODES_PER_GROUP(sb),
936 &sbi->s_flex_groups[flex_group].free_inodes);
939 ext4_handle_dirty_super(handle, sb);
942 if ((err2 = ext4_journal_stop(handle)) && !err)
945 update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
946 sizeof(struct ext4_super_block));
947 update_backups(sb, primary->b_blocknr, primary->b_data,
953 } /* ext4_group_add */
956 * Extend the filesystem to the new number of blocks specified. This entry
957 * point is only used to extend the current filesystem to the end of the last
958 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
959 * for emergencies (because it has no dependencies on reserved blocks).
961 * If we _really_ wanted, we could use default values to call ext4_group_add()
962 * allow the "remount" trick to work for arbitrary resizing, assuming enough
963 * GDT blocks are reserved to grow to the desired size.
965 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
966 ext4_fsblk_t n_blocks_count)
968 ext4_fsblk_t o_blocks_count;
971 struct buffer_head *bh;
976 o_blocks_count = ext4_blocks_count(es);
978 if (test_opt(sb, DEBUG))
979 printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n",
980 o_blocks_count, n_blocks_count);
982 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
985 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
986 printk(KERN_ERR "EXT4-fs: filesystem on %s:"
987 " too large to resize to %llu blocks safely\n",
988 sb->s_id, n_blocks_count);
989 if (sizeof(sector_t) < 8)
990 ext4_warning(sb, "CONFIG_LBDAF not enabled");
994 if (n_blocks_count < o_blocks_count) {
995 ext4_warning(sb, "can't shrink FS - resize aborted");
999 /* Handle the remaining blocks in the last group only. */
1000 ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1003 ext4_warning(sb, "need to use ext2online to resize further");
1007 add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1009 if (o_blocks_count + add < o_blocks_count) {
1010 ext4_warning(sb, "blocks_count overflow");
1014 if (o_blocks_count + add > n_blocks_count)
1015 add = n_blocks_count - o_blocks_count;
1017 if (o_blocks_count + add < n_blocks_count)
1018 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1019 o_blocks_count + add, add);
1021 /* See if the device is actually as big as what was requested */
1022 bh = sb_bread(sb, o_blocks_count + add - 1);
1024 ext4_warning(sb, "can't read last block, resize aborted");
1029 /* We will update the superblock, one block bitmap, and
1030 * one group descriptor via ext4_free_blocks().
1032 handle = ext4_journal_start_sb(sb, 3);
1033 if (IS_ERR(handle)) {
1034 err = PTR_ERR(handle);
1035 ext4_warning(sb, "error %d on journal start", err);
1039 if ((err = ext4_journal_get_write_access(handle,
1040 EXT4_SB(sb)->s_sbh))) {
1041 ext4_warning(sb, "error %d on journal write access", err);
1042 ext4_journal_stop(handle);
1045 ext4_blocks_count_set(es, o_blocks_count + add);
1046 ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1047 o_blocks_count + add);
1048 /* We add the blocks to the bitmap and set the group need init bit */
1049 ext4_add_groupblocks(handle, sb, o_blocks_count, add);
1050 ext4_handle_dirty_super(handle, sb);
1051 ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1052 o_blocks_count + add);
1053 if ((err = ext4_journal_stop(handle)))
1056 if (test_opt(sb, DEBUG))
1057 printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
1058 ext4_blocks_count(es));
1059 update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es,
1060 sizeof(struct ext4_super_block));
1063 } /* ext4_group_extend */