/* * linux/fs/ext4/resize.c * * Support for resizing an ext4 filesystem while it is mounted. * * Copyright (C) 2001, 2002 Andreas Dilger * * This could probably be made into a module, because it is not often in use. */ #define EXT4FS_DEBUG #include #include #include "ext4_jbd2.h" #include "group.h" #define outside(b, first, last) ((b) < (first) || (b) >= (last)) #define inside(b, first, last) ((b) >= (first) && (b) < (last)) static int verify_group_input(struct super_block *sb, struct ext4_new_group_data *input) { struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_super_block *es = sbi->s_es; ext4_fsblk_t start = ext4_blocks_count(es); ext4_fsblk_t end = start + input->blocks_count; ext4_group_t group = input->group; ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group; unsigned overhead = ext4_bg_has_super(sb, group) ? (1 + ext4_bg_num_gdb(sb, group) + le16_to_cpu(es->s_reserved_gdt_blocks)) : 0; ext4_fsblk_t metaend = start + overhead; struct buffer_head *bh = NULL; ext4_grpblk_t free_blocks_count, offset; int err = -EINVAL; input->free_blocks_count = free_blocks_count = input->blocks_count - 2 - overhead - sbi->s_itb_per_group; if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks " "(%d free, %u reserved)\n", ext4_bg_has_super(sb, input->group) ? "normal" : "no-super", input->group, input->blocks_count, free_blocks_count, input->reserved_blocks); ext4_get_group_no_and_offset(sb, start, NULL, &offset); if (group != sbi->s_groups_count) ext4_warning(sb, __func__, "Cannot add at group %u (only %u groups)", input->group, sbi->s_groups_count); else if (offset != 0) ext4_warning(sb, __func__, "Last group not full"); else if (input->reserved_blocks > input->blocks_count / 5) ext4_warning(sb, __func__, "Reserved blocks too high (%u)", input->reserved_blocks); else if (free_blocks_count < 0) ext4_warning(sb, __func__, "Bad blocks count %u", input->blocks_count); else if (!(bh = sb_bread(sb, end - 1))) ext4_warning(sb, __func__, "Cannot read last block (%llu)", end - 1); else if (outside(input->block_bitmap, start, end)) ext4_warning(sb, __func__, "Block bitmap not in group (block %llu)", (unsigned long long)input->block_bitmap); else if (outside(input->inode_bitmap, start, end)) ext4_warning(sb, __func__, "Inode bitmap not in group (block %llu)", (unsigned long long)input->inode_bitmap); else if (outside(input->inode_table, start, end) || outside(itend - 1, start, end)) ext4_warning(sb, __func__, "Inode table not in group (blocks %llu-%llu)", (unsigned long long)input->inode_table, itend - 1); else if (input->inode_bitmap == input->block_bitmap) ext4_warning(sb, __func__, "Block bitmap same as inode bitmap (%llu)", (unsigned long long)input->block_bitmap); else if (inside(input->block_bitmap, input->inode_table, itend)) ext4_warning(sb, __func__, "Block bitmap (%llu) in inode table (%llu-%llu)", (unsigned long long)input->block_bitmap, (unsigned long long)input->inode_table, itend - 1); else if (inside(input->inode_bitmap, input->inode_table, itend)) ext4_warning(sb, __func__, "Inode bitmap (%llu) in inode table (%llu-%llu)", (unsigned long long)input->inode_bitmap, (unsigned long long)input->inode_table, itend - 1); else if (inside(input->block_bitmap, start, metaend)) ext4_warning(sb, __func__, "Block bitmap (%llu) in GDT table" " (%llu-%llu)", (unsigned long long)input->block_bitmap, start, metaend - 1); else if (inside(input->inode_bitmap, start, metaend)) ext4_warning(sb, __func__, "Inode bitmap (%llu) in GDT table" " (%llu-%llu)", (unsigned long long)input->inode_bitmap, start, metaend - 1); else if (inside(input->inode_table, start, metaend) || inside(itend - 1, start, metaend)) ext4_warning(sb, __func__, "Inode table (%llu-%llu) overlaps" "GDT table (%llu-%llu)", (unsigned long long)input->inode_table, itend - 1, start, metaend - 1); else err = 0; brelse(bh); return err; } static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, ext4_fsblk_t blk) { struct buffer_head *bh; int err; bh = sb_getblk(sb, blk); if (!bh) return ERR_PTR(-EIO); if ((err = ext4_journal_get_write_access(handle, bh))) { brelse(bh); bh = ERR_PTR(err); } else { lock_buffer(bh); memset(bh->b_data, 0, sb->s_blocksize); set_buffer_uptodate(bh); unlock_buffer(bh); } return bh; } /* * If we have fewer than thresh credits, extend by EXT4_MAX_TRANS_DATA. * If that fails, restart the transaction & regain write access for the * buffer head which is used for block_bitmap modifications. */ static int extend_or_restart_transaction(handle_t *handle, int thresh, struct buffer_head *bh) { int err; if (ext4_handle_has_enough_credits(handle, thresh)) return 0; err = ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA); if (err < 0) return err; if (err) { if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA))) return err; if ((err = ext4_journal_get_write_access(handle, bh))) return err; } return 0; } /* * Set up the block and inode bitmaps, and the inode table for the new group. * This doesn't need to be part of the main transaction, since we are only * changing blocks outside the actual filesystem. We still do journaling to * ensure the recovery is correct in case of a failure just after resize. * If any part of this fails, we simply abort the resize. */ static int setup_new_group_blocks(struct super_block *sb, struct ext4_new_group_data *input) { struct ext4_sb_info *sbi = EXT4_SB(sb); ext4_fsblk_t start = ext4_group_first_block_no(sb, input->group); int reserved_gdb = ext4_bg_has_super(sb, input->group) ? le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0; unsigned long gdblocks = ext4_bg_num_gdb(sb, input->group); struct buffer_head *bh; handle_t *handle; ext4_fsblk_t block; ext4_grpblk_t bit; int i; int err = 0, err2; /* This transaction may be extended/restarted along the way */ handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA); if (IS_ERR(handle)) return PTR_ERR(handle); lock_super(sb); if (input->group != sbi->s_groups_count) { err = -EBUSY; goto exit_journal; } if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) { err = PTR_ERR(bh); goto exit_journal; } if (ext4_bg_has_super(sb, input->group)) { ext4_debug("mark backup superblock %#04llx (+0)\n", start); ext4_set_bit(0, bh->b_data); } /* Copy all of the GDT blocks into the backup in this group */ for (i = 0, bit = 1, block = start + 1; i < gdblocks; i++, block++, bit++) { struct buffer_head *gdb; ext4_debug("update backup group %#04llx (+%d)\n", block, bit); if ((err = extend_or_restart_transaction(handle, 1, bh))) goto exit_bh; gdb = sb_getblk(sb, block); if (!gdb) { err = -EIO; goto exit_bh; } if ((err = ext4_journal_get_write_access(handle, gdb))) { brelse(gdb); goto exit_bh; } lock_buffer(gdb); memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size); set_buffer_uptodate(gdb); unlock_buffer(gdb); ext4_handle_dirty_metadata(handle, NULL, gdb); ext4_set_bit(bit, bh->b_data); brelse(gdb); } /* Zero out all of the reserved backup group descriptor table blocks */ for (i = 0, bit = gdblocks + 1, block = start + bit; i < reserved_gdb; i++, block++, bit++) { struct buffer_head *gdb; ext4_debug("clear reserved block %#04llx (+%d)\n", block, bit); if ((err = extend_or_restart_transaction(handle, 1, bh))) goto exit_bh; if (IS_ERR(gdb = bclean(handle, sb, block))) { err = PTR_ERR(bh); goto exit_bh; } ext4_handle_dirty_metadata(handle, NULL, gdb); ext4_set_bit(bit, bh->b_data); brelse(gdb); } ext4_debug("mark block bitmap %#04llx (+%llu)\n", input->block_bitmap, input->block_bitmap - start); ext4_set_bit(input->block_bitmap - start, bh->b_data); ext4_debug("mark inode bitmap %#04llx (+%llu)\n", input->inode_bitmap, input->inode_bitmap - start); ext4_set_bit(input->inode_bitmap - start, bh->b_data); /* Zero out all of the inode table blocks */ for (i = 0, block = input->inode_table, bit = block - start; i < sbi->s_itb_per_group; i++, bit++, block++) { struct buffer_head *it; ext4_debug("clear inode block %#04llx (+%d)\n", block, bit); if ((err = extend_or_restart_transaction(handle, 1, bh))) goto exit_bh; if (IS_ERR(it = bclean(handle, sb, block))) { err = PTR_ERR(it); goto exit_bh; } ext4_handle_dirty_metadata(handle, NULL, it); brelse(it); ext4_set_bit(bit, bh->b_data); } if ((err = extend_or_restart_transaction(handle, 2, bh))) goto exit_bh; mark_bitmap_end(input->blocks_count, sb->s_blocksize * 8, bh->b_data); ext4_handle_dirty_metadata(handle, NULL, bh); brelse(bh); /* Mark unused entries in inode bitmap used */ ext4_debug("clear inode bitmap %#04llx (+%llu)\n", input->inode_bitmap, input->inode_bitmap - start); if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) { err = PTR_ERR(bh); goto exit_journal; } mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8, bh->b_data); ext4_handle_dirty_metadata(handle, NULL, bh); exit_bh: brelse(bh); exit_journal: unlock_super(sb); if ((err2 = ext4_journal_stop(handle)) && !err) err = err2; return err; } /* * Iterate through the groups which hold BACKUP superblock/GDT copies in an * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before * calling this for the first time. In a sparse filesystem it will be the * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ... * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ... */ static unsigned ext4_list_backups(struct super_block *sb, unsigned *three, unsigned *five, unsigned *seven) { unsigned *min = three; int mult = 3; unsigned ret; if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) { ret = *min; *min += 1; return ret; } if (*five < *min) { min = five; mult = 5; } if (*seven < *min) { min = seven; mult = 7; } ret = *min; *min *= mult; return ret; } /* * Check that all of the backup GDT blocks are held in the primary GDT block. * It is assumed that they are stored in group order. Returns the number of * groups in current filesystem that have BACKUPS, or -ve error code. */ static int verify_reserved_gdb(struct super_block *sb, struct buffer_head *primary) { const ext4_fsblk_t blk = primary->b_blocknr; const ext4_group_t end = EXT4_SB(sb)->s_groups_count; unsigned three = 1; unsigned five = 5; unsigned seven = 7; unsigned grp; __le32 *p = (__le32 *)primary->b_data; int gdbackups = 0; while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) { if (le32_to_cpu(*p++) != grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){ ext4_warning(sb, __func__, "reserved GDT %llu" " missing grp %d (%llu)", blk, grp, grp * (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) + blk); return -EINVAL; } if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb)) return -EFBIG; } return gdbackups; } /* * Called when we need to bring a reserved group descriptor table block into * use from the resize inode. The primary copy of the new GDT block currently * is an indirect block (under the double indirect block in the resize inode). * The new backup GDT blocks will be stored as leaf blocks in this indirect * block, in group order. Even though we know all the block numbers we need, * we check to ensure that the resize inode has actually reserved these blocks. * * Don't need to update the block bitmaps because the blocks are still in use. * * We get all of the error cases out of the way, so that we are sure to not * fail once we start modifying the data on disk, because JBD has no rollback. */ static int add_new_gdb(handle_t *handle, struct inode *inode, struct ext4_new_group_data *input, struct buffer_head **primary) { struct super_block *sb = inode->i_sb; struct ext4_super_block *es = EXT4_SB(sb)->s_es; unsigned long gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb); ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num; struct buffer_head **o_group_desc, **n_group_desc; struct buffer_head *dind; int gdbackups; struct ext4_iloc iloc; __le32 *data; int err; if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n", gdb_num); /* * If we are not using the primary superblock/GDT copy don't resize, * because the user tools have no way of handling this. Probably a * bad time to do it anyways. */ if (EXT4_SB(sb)->s_sbh->b_blocknr != le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) { ext4_warning(sb, __func__, "won't resize using backup superblock at %llu", (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr); return -EPERM; } *primary = sb_bread(sb, gdblock); if (!*primary) return -EIO; if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) { err = gdbackups; goto exit_bh; } data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; dind = sb_bread(sb, le32_to_cpu(*data)); if (!dind) { err = -EIO; goto exit_bh; } data = (__le32 *)dind->b_data; if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) { ext4_warning(sb, __func__, "new group %u GDT block %llu not reserved", input->group, gdblock); err = -EINVAL; goto exit_dind; } if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh))) goto exit_dind; if ((err = ext4_journal_get_write_access(handle, *primary))) goto exit_sbh; if ((err = ext4_journal_get_write_access(handle, dind))) goto exit_primary; /* ext4_reserve_inode_write() gets a reference on the iloc */ if ((err = ext4_reserve_inode_write(handle, inode, &iloc))) goto exit_dindj; n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *), GFP_NOFS); if (!n_group_desc) { err = -ENOMEM; ext4_warning(sb, __func__, "not enough memory for %lu groups", gdb_num + 1); goto exit_inode; } /* * Finally, we have all of the possible failures behind us... * * Remove new GDT block from inode double-indirect block and clear out * the new GDT block for use (which also "frees" the backup GDT blocks * from the reserved inode). We don't need to change the bitmaps for * these blocks, because they are marked as in-use from being in the * reserved inode, and will become GDT blocks (primary and backup). */ data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0; ext4_handle_dirty_metadata(handle, NULL, dind); brelse(dind); inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9; ext4_mark_iloc_dirty(handle, inode, &iloc); memset((*primary)->b_data, 0, sb->s_blocksize); ext4_handle_dirty_metadata(handle, NULL, *primary); o_group_desc = EXT4_SB(sb)->s_group_desc; memcpy(n_group_desc, o_group_desc, EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *)); n_group_desc[gdb_num] = *primary; EXT4_SB(sb)->s_group_desc = n_group_desc; EXT4_SB(sb)->s_gdb_count++; kfree(o_group_desc); le16_add_cpu(&es->s_reserved_gdt_blocks, -1); ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); return 0; exit_inode: /* ext4_journal_release_buffer(handle, iloc.bh); */ brelse(iloc.bh); exit_dindj: /* ext4_journal_release_buffer(handle, dind); */ exit_primary: /* ext4_journal_release_buffer(handle, *primary); */ exit_sbh: /* ext4_journal_release_buffer(handle, *primary); */ exit_dind: brelse(dind); exit_bh: brelse(*primary); ext4_debug("leaving with error %d\n", err); return err; } /* * Called when we are adding a new group which has a backup copy of each of * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks. * We need to add these reserved backup GDT blocks to the resize inode, so * that they are kept for future resizing and not allocated to files. * * Each reserved backup GDT block will go into a different indirect block. * The indirect blocks are actually the primary reserved GDT blocks, * so we know in advance what their block numbers are. We only get the * double-indirect block to verify it is pointing to the primary reserved * GDT blocks so we don't overwrite a data block by accident. The reserved * backup GDT blocks are stored in their reserved primary GDT block. */ static int reserve_backup_gdb(handle_t *handle, struct inode *inode, struct ext4_new_group_data *input) { struct super_block *sb = inode->i_sb; int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks); struct buffer_head **primary; struct buffer_head *dind; struct ext4_iloc iloc; ext4_fsblk_t blk; __le32 *data, *end; int gdbackups = 0; int res, i; int err; primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_NOFS); if (!primary) return -ENOMEM; data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; dind = sb_bread(sb, le32_to_cpu(*data)); if (!dind) { err = -EIO; goto exit_free; } blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count; data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count % EXT4_ADDR_PER_BLOCK(sb)); end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb); /* Get each reserved primary GDT block and verify it holds backups */ for (res = 0; res < reserved_gdb; res++, blk++) { if (le32_to_cpu(*data) != blk) { ext4_warning(sb, __func__, "reserved block %llu" " not at offset %ld", blk, (long)(data - (__le32 *)dind->b_data)); err = -EINVAL; goto exit_bh; } primary[res] = sb_bread(sb, blk); if (!primary[res]) { err = -EIO; goto exit_bh; } if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) { brelse(primary[res]); err = gdbackups; goto exit_bh; } if (++data >= end) data = (__le32 *)dind->b_data; } for (i = 0; i < reserved_gdb; i++) { if ((err = ext4_journal_get_write_access(handle, primary[i]))) { /* int j; for (j = 0; j < i; j++) ext4_journal_release_buffer(handle, primary[j]); */ goto exit_bh; } } if ((err = ext4_reserve_inode_write(handle, inode, &iloc))) goto exit_bh; /* * Finally we can add each of the reserved backup GDT blocks from * the new group to its reserved primary GDT block. */ blk = input->group * EXT4_BLOCKS_PER_GROUP(sb); for (i = 0; i < reserved_gdb; i++) { int err2; data = (__le32 *)primary[i]->b_data; /* printk("reserving backup %lu[%u] = %lu\n", primary[i]->b_blocknr, gdbackups, blk + primary[i]->b_blocknr); */ data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr); err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]); if (!err) err = err2; } inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9; ext4_mark_iloc_dirty(handle, inode, &iloc); exit_bh: while (--res >= 0) brelse(primary[res]); brelse(dind); exit_free: kfree(primary); return err; } /* * Update the backup copies of the ext4 metadata. These don't need to be part * of the main resize transaction, because e2fsck will re-write them if there * is a problem (basically only OOM will cause a problem). However, we * _should_ update the backups if possible, in case the primary gets trashed * for some reason and we need to run e2fsck from a backup superblock. The * important part is that the new block and inode counts are in the backup * superblocks, and the location of the new group metadata in the GDT backups. * * We do not need lock_super() for this, because these blocks are not * otherwise touched by the filesystem code when it is mounted. We don't * need to worry about last changing from sbi->s_groups_count, because the * worst that can happen is that we do not copy the full number of backups * at this time. The resize which changed s_groups_count will backup again. */ static void update_backups(struct super_block *sb, int blk_off, char *data, int size) { struct ext4_sb_info *sbi = EXT4_SB(sb); const ext4_group_t last = sbi->s_groups_count; const int bpg = EXT4_BLOCKS_PER_GROUP(sb); unsigned three = 1; unsigned five = 5; unsigned seven = 7; ext4_group_t group; int rest = sb->s_blocksize - size; handle_t *handle; int err = 0, err2; handle = ext4_journal_start_sb(sb, EXT4_MAX_TRANS_DATA); if (IS_ERR(handle)) { group = 1; err = PTR_ERR(handle); goto exit_err; } while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) { struct buffer_head *bh; /* Out of journal space, and can't get more - abort - so sad */ if (ext4_handle_valid(handle) && handle->h_buffer_credits == 0 && ext4_journal_extend(handle, EXT4_MAX_TRANS_DATA) && (err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA))) break; bh = sb_getblk(sb, group * bpg + blk_off); if (!bh) { err = -EIO; break; } ext4_debug("update metadata backup %#04lx\n", (unsigned long)bh->b_blocknr); if ((err = ext4_journal_get_write_access(handle, bh))) break; lock_buffer(bh); memcpy(bh->b_data, data, size); if (rest) memset(bh->b_data + size, 0, rest); set_buffer_uptodate(bh); unlock_buffer(bh); ext4_handle_dirty_metadata(handle, NULL, bh); brelse(bh); } if ((err2 = ext4_journal_stop(handle)) && !err) err = err2; /* * Ugh! Need to have e2fsck write the backup copies. It is too * late to revert the resize, we shouldn't fail just because of * the backup copies (they are only needed in case of corruption). * * However, if we got here we have a journal problem too, so we * can't really start a transaction to mark the superblock. * Chicken out and just set the flag on the hope it will be written * to disk, and if not - we will simply wait until next fsck. */ exit_err: if (err) { ext4_warning(sb, __func__, "can't update backup for group %u (err %d), " "forcing fsck on next reboot", group, err); sbi->s_mount_state &= ~EXT4_VALID_FS; sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS); mark_buffer_dirty(sbi->s_sbh); } } /* Add group descriptor data to an existing or new group descriptor block. * Ensure we handle all possible error conditions _before_ we start modifying * the filesystem, because we cannot abort the transaction and not have it * write the data to disk. * * If we are on a GDT block boundary, we need to get the reserved GDT block. * Otherwise, we may need to add backup GDT blocks for a sparse group. * * We only need to hold the superblock lock while we are actually adding * in the new group's counts to the superblock. Prior to that we have * not really "added" the group at all. We re-check that we are still * adding in the last group in case things have changed since verifying. */ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input) { struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_super_block *es = sbi->s_es; int reserved_gdb = ext4_bg_has_super(sb, input->group) ? le16_to_cpu(es->s_reserved_gdt_blocks) : 0; struct buffer_head *primary = NULL; struct ext4_group_desc *gdp; struct inode *inode = NULL; handle_t *handle; int gdb_off, gdb_num; int num_grp_locked = 0; int err, err2; gdb_num = input->group / EXT4_DESC_PER_BLOCK(sb); gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb); if (gdb_off == 0 && !EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER)) { ext4_warning(sb, __func__, "Can't resize non-sparse filesystem further"); return -EPERM; } if (ext4_blocks_count(es) + input->blocks_count < ext4_blocks_count(es)) { ext4_warning(sb, __func__, "blocks_count overflow"); return -EINVAL; } if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) < le32_to_cpu(es->s_inodes_count)) { ext4_warning(sb, __func__, "inodes_count overflow"); return -EINVAL; } if (reserved_gdb || gdb_off == 0) { if (!EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_RESIZE_INODE) || !le16_to_cpu(es->s_reserved_gdt_blocks)) { ext4_warning(sb, __func__, "No reserved GDT blocks, can't resize"); return -EPERM; } inode = ext4_iget(sb, EXT4_RESIZE_INO); if (IS_ERR(inode)) { ext4_warning(sb, __func__, "Error opening resize inode"); return PTR_ERR(inode); } } if ((err = verify_group_input(sb, input))) goto exit_put; if ((err = setup_new_group_blocks(sb, input))) goto exit_put; /* * We will always be modifying at least the superblock and a GDT * block. If we are adding a group past the last current GDT block, * we will also modify the inode and the dindirect block. If we * are adding a group with superblock/GDT backups we will also * modify each of the reserved GDT dindirect blocks. */ handle = ext4_journal_start_sb(sb, ext4_bg_has_super(sb, input->group) ? 3 + reserved_gdb : 4); if (IS_ERR(handle)) { err = PTR_ERR(handle); goto exit_put; } lock_super(sb); if (input->group != sbi->s_groups_count) { ext4_warning(sb, __func__, "multiple resizers run on filesystem!"); err = -EBUSY; goto exit_journal; } if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh))) goto exit_journal; /* * We will only either add reserved group blocks to a backup group * or remove reserved blocks for the first group in a new group block. * Doing both would be mean more complex code, and sane people don't * use non-sparse filesystems anymore. This is already checked above. */ if (gdb_off) { primary = sbi->s_group_desc[gdb_num]; if ((err = ext4_journal_get_write_access(handle, primary))) goto exit_journal; if (reserved_gdb && ext4_bg_num_gdb(sb, input->group) && (err = reserve_backup_gdb(handle, inode, input))) goto exit_journal; } else if ((err = add_new_gdb(handle, inode, input, &primary))) goto exit_journal; /* * OK, now we've set up the new group. Time to make it active. * * Current kernels don't lock all allocations via lock_super(), * so we have to be safe wrt. concurrent accesses the group * data. So we need to be careful to set all of the relevant * group descriptor data etc. *before* we enable the group. * * The key field here is sbi->s_groups_count: as long as * that retains its old value, nobody is going to access the new * group. * * So first we update all the descriptor metadata for the new * group; then we update the total disk blocks count; then we * update the groups count to enable the group; then finally we * update the free space counts so that the system can start * using the new disk blocks. */ num_grp_locked = ext4_mb_get_buddy_cache_lock(sb, input->group); /* Update group descriptor block for new group */ gdp = (struct ext4_group_desc *)((char *)primary->b_data + gdb_off * EXT4_DESC_SIZE(sb)); ext4_block_bitmap_set(sb, gdp, input->block_bitmap); /* LV FIXME */ ext4_inode_bitmap_set(sb, gdp, input->inode_bitmap); /* LV FIXME */ ext4_inode_table_set(sb, gdp, input->inode_table); /* LV FIXME */ ext4_free_blks_set(sb, gdp, input->free_blocks_count); ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb)); gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED); gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp); /* * We can allocate memory for mb_alloc based on the new group * descriptor */ err = ext4_mb_add_groupinfo(sb, input->group, gdp); if (err) { ext4_mb_put_buddy_cache_lock(sb, input->group, num_grp_locked); goto exit_journal; } /* * Make the new blocks and inodes valid next. We do this before * increasing the group count so that once the group is enabled, * all of its blocks and inodes are already valid. * * We always allocate group-by-group, then block-by-block or * inode-by-inode within a group, so enabling these * blocks/inodes before the group is live won't actually let us * allocate the new space yet. */ ext4_blocks_count_set(es, ext4_blocks_count(es) + input->blocks_count); le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb)); /* * We need to protect s_groups_count against other CPUs seeing * inconsistent state in the superblock. * * The precise rules we use are: * * * Writers of s_groups_count *must* hold lock_super * AND * * Writers must perform a smp_wmb() after updating all dependent * data and before modifying the groups count * * * Readers must hold lock_super() over the access * OR * * Readers must perform an smp_rmb() after reading the groups count * and before reading any dependent data. * * NB. These rules can be relaxed when checking the group count * while freeing data, as we can only allocate from a block * group after serialising against the group count, and we can * only then free after serialising in turn against that * allocation. */ smp_wmb(); /* Update the global fs size fields */ sbi->s_groups_count++; ext4_mb_put_buddy_cache_lock(sb, input->group, num_grp_locked); ext4_handle_dirty_metadata(handle, NULL, primary); /* Update the reserved block counts only once the new group is * active. */ ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) + input->reserved_blocks); /* Update the free space counts */ percpu_counter_add(&sbi->s_freeblocks_counter, input->free_blocks_count); percpu_counter_add(&sbi->s_freeinodes_counter, EXT4_INODES_PER_GROUP(sb)); if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { ext4_group_t flex_group; flex_group = ext4_flex_group(sbi, input->group); sbi->s_flex_groups[flex_group].free_blocks += input->free_blocks_count; sbi->s_flex_groups[flex_group].free_inodes += EXT4_INODES_PER_GROUP(sb); } ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh); sb->s_dirt = 1; exit_journal: unlock_super(sb); if ((err2 = ext4_journal_stop(handle)) && !err) err = err2; if (!err) { update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, sizeof(struct ext4_super_block)); update_backups(sb, primary->b_blocknr, primary->b_data, primary->b_size); } exit_put: iput(inode); return err; } /* ext4_group_add */ /* * Extend the filesystem to the new number of blocks specified. This entry * point is only used to extend the current filesystem to the end of the last * existing group. It can be accessed via ioctl, or by "remount,resize=" * for emergencies (because it has no dependencies on reserved blocks). * * If we _really_ wanted, we could use default values to call ext4_group_add() * allow the "remount" trick to work for arbitrary resizing, assuming enough * GDT blocks are reserved to grow to the desired size. */ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es, ext4_fsblk_t n_blocks_count) { ext4_fsblk_t o_blocks_count; ext4_group_t o_groups_count; ext4_grpblk_t last; ext4_grpblk_t add; struct buffer_head *bh; handle_t *handle; int err; ext4_group_t group; /* We don't need to worry about locking wrt other resizers just * yet: we're going to revalidate es->s_blocks_count after * taking lock_super() below. */ o_blocks_count = ext4_blocks_count(es); o_groups_count = EXT4_SB(sb)->s_groups_count; if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: extending last group from %llu uto %llu blocks\n", o_blocks_count, n_blocks_count); if (n_blocks_count == 0 || n_blocks_count == o_blocks_count) return 0; if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { printk(KERN_ERR "EXT4-fs: filesystem on %s:" " too large to resize to %llu blocks safely\n", sb->s_id, n_blocks_count); if (sizeof(sector_t) < 8) ext4_warning(sb, __func__, "CONFIG_LBD not enabled"); return -EINVAL; } if (n_blocks_count < o_blocks_count) { ext4_warning(sb, __func__, "can't shrink FS - resize aborted"); return -EBUSY; } /* Handle the remaining blocks in the last group only. */ ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last); if (last == 0) { ext4_warning(sb, __func__, "need to use ext2online to resize further"); return -EPERM; } add = EXT4_BLOCKS_PER_GROUP(sb) - last; if (o_blocks_count + add < o_blocks_count) { ext4_warning(sb, __func__, "blocks_count overflow"); return -EINVAL; } if (o_blocks_count + add > n_blocks_count) add = n_blocks_count - o_blocks_count; if (o_blocks_count + add < n_blocks_count) ext4_warning(sb, __func__, "will only finish group (%llu" " blocks, %u new)", o_blocks_count + add, add); /* See if the device is actually as big as what was requested */ bh = sb_bread(sb, o_blocks_count + add - 1); if (!bh) { ext4_warning(sb, __func__, "can't read last block, resize aborted"); return -ENOSPC; } brelse(bh); /* We will update the superblock, one block bitmap, and * one group descriptor via ext4_free_blocks(). */ handle = ext4_journal_start_sb(sb, 3); if (IS_ERR(handle)) { err = PTR_ERR(handle); ext4_warning(sb, __func__, "error %d on journal start", err); goto exit_put; } lock_super(sb); if (o_blocks_count != ext4_blocks_count(es)) { ext4_warning(sb, __func__, "multiple resizers run on filesystem!"); unlock_super(sb); ext4_journal_stop(handle); err = -EBUSY; goto exit_put; } if ((err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh))) { ext4_warning(sb, __func__, "error %d on journal write access", err); unlock_super(sb); ext4_journal_stop(handle); goto exit_put; } ext4_blocks_count_set(es, o_blocks_count + add); ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); sb->s_dirt = 1; unlock_super(sb); ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count, o_blocks_count + add); /* We add the blocks to the bitmap and set the group need init bit */ ext4_add_groupblocks(handle, sb, o_blocks_count, add); ext4_debug("freed blocks %llu through %llu\n", o_blocks_count, o_blocks_count + add); if ((err = ext4_journal_stop(handle))) goto exit_put; if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n", ext4_blocks_count(es)); update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es, sizeof(struct ext4_super_block)); exit_put: return err; } /* ext4_group_extend */