diff options
Diffstat (limited to 'fs/ext4/resize.c')
| -rw-r--r-- | fs/ext4/resize.c | 2143 |
1 files changed, 2143 insertions, 0 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c new file mode 100644 index 000000000..d37493b39 --- /dev/null +++ b/fs/ext4/resize.c @@ -0,0 +1,2143 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/ext4/resize.c + * + * Support for resizing an ext4 filesystem while it is mounted. + * + * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com> + * + * This could probably be made into a module, because it is not often in use. + */ + + +#define EXT4FS_DEBUG + +#include <linux/errno.h> +#include <linux/slab.h> + +#include "ext4_jbd2.h" + +struct ext4_rcu_ptr { + struct rcu_head rcu; + void *ptr; +}; + +static void ext4_rcu_ptr_callback(struct rcu_head *head) +{ + struct ext4_rcu_ptr *ptr; + + ptr = container_of(head, struct ext4_rcu_ptr, rcu); + kvfree(ptr->ptr); + kfree(ptr); +} + +void ext4_kvfree_array_rcu(void *to_free) +{ + struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL); + + if (ptr) { + ptr->ptr = to_free; + call_rcu(&ptr->rcu, ext4_rcu_ptr_callback); + return; + } + synchronize_rcu(); + kvfree(to_free); +} + +int ext4_resize_begin(struct super_block *sb) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + int ret = 0; + + if (!capable(CAP_SYS_RESOURCE)) + return -EPERM; + + /* + * If the reserved GDT blocks is non-zero, the resize_inode feature + * should always be set. + */ + if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks && + !ext4_has_feature_resize_inode(sb)) { + ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero"); + return -EFSCORRUPTED; + } + + /* + * 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_B2C(sbi, sbi->s_sbh->b_blocknr) != + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) { + ext4_warning(sb, "won't resize using backup superblock at %llu", + (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr); + return -EPERM; + } + + /* + * We are not allowed to do online-resizing on a filesystem mounted + * with error, because it can destroy the filesystem easily. + */ + if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) { + ext4_warning(sb, "There are errors in the filesystem, " + "so online resizing is not allowed"); + return -EPERM; + } + + if (ext4_has_feature_sparse_super2(sb)) { + ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2"); + return -EOPNOTSUPP; + } + + if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING, + &EXT4_SB(sb)->s_ext4_flags)) + ret = -EBUSY; + + return ret; +} + +void ext4_resize_end(struct super_block *sb) +{ + clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags); + smp_mb__after_atomic(); +} + +static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb, + ext4_group_t group) { + return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) << + EXT4_DESC_PER_BLOCK_BITS(sb); +} + +static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb, + ext4_group_t group) { + group = ext4_meta_bg_first_group(sb, group); + return ext4_group_first_block_no(sb, group); +} + +static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb, + ext4_group_t group) { + ext4_grpblk_t overhead; + overhead = ext4_bg_num_gdb(sb, group); + if (ext4_bg_has_super(sb, group)) + overhead += 1 + + le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks); + return overhead; +} + +#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_fsblk_t metaend; + struct buffer_head *bh = NULL; + ext4_grpblk_t free_blocks_count, offset; + int err = -EINVAL; + + if (group != sbi->s_groups_count) { + ext4_warning(sb, "Cannot add at group %u (only %u groups)", + input->group, sbi->s_groups_count); + return -EINVAL; + } + + overhead = ext4_group_overhead_blocks(sb, group); + metaend = start + overhead; + input->free_clusters_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 (offset != 0) + ext4_warning(sb, "Last group not full"); + else if (input->reserved_blocks > input->blocks_count / 5) + ext4_warning(sb, "Reserved blocks too high (%u)", + input->reserved_blocks); + else if (free_blocks_count < 0) + ext4_warning(sb, "Bad blocks count %u", + input->blocks_count); + else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) { + err = PTR_ERR(bh); + bh = NULL; + ext4_warning(sb, "Cannot read last block (%llu)", + end - 1); + } else if (outside(input->block_bitmap, start, end)) + ext4_warning(sb, "Block bitmap not in group (block %llu)", + (unsigned long long)input->block_bitmap); + else if (outside(input->inode_bitmap, start, end)) + ext4_warning(sb, "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, "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, "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, "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, "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, "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, "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, "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; +} + +/* + * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex + * group each time. + */ +struct ext4_new_flex_group_data { + struct ext4_new_group_data *groups; /* new_group_data for groups + in the flex group */ + __u16 *bg_flags; /* block group flags of groups + in @groups */ + ext4_group_t count; /* number of groups in @groups + */ +}; + +/* + * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of + * @flexbg_size. + * + * Returns NULL on failure otherwise address of the allocated structure. + */ +static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size) +{ + struct ext4_new_flex_group_data *flex_gd; + + flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS); + if (flex_gd == NULL) + goto out3; + + if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data)) + goto out2; + flex_gd->count = flexbg_size; + + flex_gd->groups = kmalloc_array(flexbg_size, + sizeof(struct ext4_new_group_data), + GFP_NOFS); + if (flex_gd->groups == NULL) + goto out2; + + flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16), + GFP_NOFS); + if (flex_gd->bg_flags == NULL) + goto out1; + + return flex_gd; + +out1: + kfree(flex_gd->groups); +out2: + kfree(flex_gd); +out3: + return NULL; +} + +static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd) +{ + kfree(flex_gd->bg_flags); + kfree(flex_gd->groups); + kfree(flex_gd); +} + +/* + * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps + * and inode tables for a flex group. + * + * This function is used by 64bit-resize. Note that this function allocates + * group tables from the 1st group of groups contained by @flexgd, which may + * be a partial of a flex group. + * + * @sb: super block of fs to which the groups belongs + * + * Returns 0 on a successful allocation of the metadata blocks in the + * block group. + */ +static int ext4_alloc_group_tables(struct super_block *sb, + struct ext4_new_flex_group_data *flex_gd, + int flexbg_size) +{ + struct ext4_new_group_data *group_data = flex_gd->groups; + ext4_fsblk_t start_blk; + ext4_fsblk_t last_blk; + ext4_group_t src_group; + ext4_group_t bb_index = 0; + ext4_group_t ib_index = 0; + ext4_group_t it_index = 0; + ext4_group_t group; + ext4_group_t last_group; + unsigned overhead; + __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0; + int i; + + BUG_ON(flex_gd->count == 0 || group_data == NULL); + + src_group = group_data[0].group; + last_group = src_group + flex_gd->count - 1; + + BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) != + (last_group & ~(flexbg_size - 1)))); +next_group: + group = group_data[0].group; + if (src_group >= group_data[0].group + flex_gd->count) + return -ENOSPC; + start_blk = ext4_group_first_block_no(sb, src_group); + last_blk = start_blk + group_data[src_group - group].blocks_count; + + overhead = ext4_group_overhead_blocks(sb, src_group); + + start_blk += overhead; + + /* We collect contiguous blocks as much as possible. */ + src_group++; + for (; src_group <= last_group; src_group++) { + overhead = ext4_group_overhead_blocks(sb, src_group); + if (overhead == 0) + last_blk += group_data[src_group - group].blocks_count; + else + break; + } + + /* Allocate block bitmaps */ + for (; bb_index < flex_gd->count; bb_index++) { + if (start_blk >= last_blk) + goto next_group; + group_data[bb_index].block_bitmap = start_blk++; + group = ext4_get_group_number(sb, start_blk - 1); + group -= group_data[0].group; + group_data[group].mdata_blocks++; + flex_gd->bg_flags[group] &= uninit_mask; + } + + /* Allocate inode bitmaps */ + for (; ib_index < flex_gd->count; ib_index++) { + if (start_blk >= last_blk) + goto next_group; + group_data[ib_index].inode_bitmap = start_blk++; + group = ext4_get_group_number(sb, start_blk - 1); + group -= group_data[0].group; + group_data[group].mdata_blocks++; + flex_gd->bg_flags[group] &= uninit_mask; + } + + /* Allocate inode tables */ + for (; it_index < flex_gd->count; it_index++) { + unsigned int itb = EXT4_SB(sb)->s_itb_per_group; + ext4_fsblk_t next_group_start; + + if (start_blk + itb > last_blk) + goto next_group; + group_data[it_index].inode_table = start_blk; + group = ext4_get_group_number(sb, start_blk); + next_group_start = ext4_group_first_block_no(sb, group + 1); + group -= group_data[0].group; + + if (start_blk + itb > next_group_start) { + flex_gd->bg_flags[group + 1] &= uninit_mask; + overhead = start_blk + itb - next_group_start; + group_data[group + 1].mdata_blocks += overhead; + itb -= overhead; + } + + group_data[group].mdata_blocks += itb; + flex_gd->bg_flags[group] &= uninit_mask; + start_blk += EXT4_SB(sb)->s_itb_per_group; + } + + /* Update free clusters count to exclude metadata blocks */ + for (i = 0; i < flex_gd->count; i++) { + group_data[i].free_clusters_count -= + EXT4_NUM_B2C(EXT4_SB(sb), + group_data[i].mdata_blocks); + } + + if (test_opt(sb, DEBUG)) { + int i; + group = group_data[0].group; + + printk(KERN_DEBUG "EXT4-fs: adding a flex group with " + "%d groups, flexbg size is %d:\n", flex_gd->count, + flexbg_size); + + for (i = 0; i < flex_gd->count; i++) { + ext4_debug( + "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n", + ext4_bg_has_super(sb, group + i) ? "normal" : + "no-super", group + i, + group_data[i].blocks_count, + group_data[i].free_clusters_count, + group_data[i].mdata_blocks); + } + } + return 0; +} + +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 (unlikely(!bh)) + return ERR_PTR(-ENOMEM); + BUFFER_TRACE(bh, "get_write_access"); + if ((err = ext4_journal_get_write_access(handle, bh))) { + brelse(bh); + bh = ERR_PTR(err); + } else { + memset(bh->b_data, 0, sb->s_blocksize); + set_buffer_uptodate(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) +{ + 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) { + err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA); + if (err) + return err; + } + + return 0; +} + +/* + * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used. + * + * Helper function for ext4_setup_new_group_blocks() which set . + * + * @sb: super block + * @handle: journal handle + * @flex_gd: flex group data + */ +static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle, + struct ext4_new_flex_group_data *flex_gd, + ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t count = last_cluster - first_cluster + 1; + ext4_group_t count2; + + ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster, + last_cluster); + for (count2 = count; count > 0; + count -= count2, first_cluster += count2) { + ext4_fsblk_t start; + struct buffer_head *bh; + ext4_group_t group; + int err; + + group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster)); + start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group)); + group -= flex_gd->groups[0].group; + + count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start); + if (count2 > count) + count2 = count; + + if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) { + BUG_ON(flex_gd->count > 1); + continue; + } + + err = extend_or_restart_transaction(handle, 1); + if (err) + return err; + + bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap); + if (unlikely(!bh)) + return -ENOMEM; + + BUFFER_TRACE(bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, bh); + if (err) { + brelse(bh); + return err; + } + ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n", + first_cluster, first_cluster - start, count2); + ext4_set_bits(bh->b_data, first_cluster - start, count2); + + err = ext4_handle_dirty_metadata(handle, NULL, bh); + brelse(bh); + if (unlikely(err)) + return err; + } + + return 0; +} + +/* + * Set up the block and inode bitmaps, and the inode table for the new groups. + * 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. + * + * setup_new_flex_group_blocks handles a flex group as follow: + * 1. copy super block and GDT, and initialize group tables if necessary. + * In this step, we only set bits in blocks bitmaps for blocks taken by + * super block and GDT. + * 2. allocate group tables in block bitmaps, that is, set bits in block + * bitmap for blocks taken by group tables. + */ +static int setup_new_flex_group_blocks(struct super_block *sb, + struct ext4_new_flex_group_data *flex_gd) +{ + int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group}; + ext4_fsblk_t start; + ext4_fsblk_t block; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + struct ext4_new_group_data *group_data = flex_gd->groups; + __u16 *bg_flags = flex_gd->bg_flags; + handle_t *handle; + ext4_group_t group, count; + struct buffer_head *bh = NULL; + int reserved_gdb, i, j, err = 0, err2; + int meta_bg; + + BUG_ON(!flex_gd->count || !group_data || + group_data[0].group != sbi->s_groups_count); + + reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks); + meta_bg = ext4_has_feature_meta_bg(sb); + + /* This transaction may be extended/restarted along the way */ + handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + group = group_data[0].group; + for (i = 0; i < flex_gd->count; i++, group++) { + unsigned long gdblocks; + ext4_grpblk_t overhead; + + gdblocks = ext4_bg_num_gdb(sb, group); + start = ext4_group_first_block_no(sb, group); + + if (meta_bg == 0 && !ext4_bg_has_super(sb, group)) + goto handle_itb; + + if (meta_bg == 1) { + ext4_group_t first_group; + first_group = ext4_meta_bg_first_group(sb, group); + if (first_group != group + 1 && + first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1) + goto handle_itb; + } + + block = start + ext4_bg_has_super(sb, group); + /* Copy all of the GDT blocks into the backup in this group */ + for (j = 0; j < gdblocks; j++, block++) { + struct buffer_head *gdb; + + ext4_debug("update backup group %#04llx\n", block); + err = extend_or_restart_transaction(handle, 1); + if (err) + goto out; + + gdb = sb_getblk(sb, block); + if (unlikely(!gdb)) { + err = -ENOMEM; + goto out; + } + + BUFFER_TRACE(gdb, "get_write_access"); + err = ext4_journal_get_write_access(handle, gdb); + if (err) { + brelse(gdb); + goto out; + } + memcpy(gdb->b_data, sbi_array_rcu_deref(sbi, + s_group_desc, j)->b_data, gdb->b_size); + set_buffer_uptodate(gdb); + + err = ext4_handle_dirty_metadata(handle, NULL, gdb); + if (unlikely(err)) { + brelse(gdb); + goto out; + } + brelse(gdb); + } + + /* Zero out all of the reserved backup group descriptor + * table blocks + */ + if (ext4_bg_has_super(sb, group)) { + err = sb_issue_zeroout(sb, gdblocks + start + 1, + reserved_gdb, GFP_NOFS); + if (err) + goto out; + } + +handle_itb: + /* Initialize group tables of the grop @group */ + if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED)) + goto handle_bb; + + /* Zero out all of the inode table blocks */ + block = group_data[i].inode_table; + ext4_debug("clear inode table blocks %#04llx -> %#04lx\n", + block, sbi->s_itb_per_group); + err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group, + GFP_NOFS); + if (err) + goto out; + +handle_bb: + if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT) + goto handle_ib; + + /* Initialize block bitmap of the @group */ + block = group_data[i].block_bitmap; + err = extend_or_restart_transaction(handle, 1); + if (err) + goto out; + + bh = bclean(handle, sb, block); + if (IS_ERR(bh)) { + err = PTR_ERR(bh); + goto out; + } + overhead = ext4_group_overhead_blocks(sb, group); + if (overhead != 0) { + ext4_debug("mark backup superblock %#04llx (+0)\n", + start); + ext4_set_bits(bh->b_data, 0, + EXT4_NUM_B2C(sbi, overhead)); + } + ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count), + sb->s_blocksize * 8, bh->b_data); + err = ext4_handle_dirty_metadata(handle, NULL, bh); + brelse(bh); + if (err) + goto out; + +handle_ib: + if (bg_flags[i] & EXT4_BG_INODE_UNINIT) + continue; + + /* Initialize inode bitmap of the @group */ + block = group_data[i].inode_bitmap; + err = extend_or_restart_transaction(handle, 1); + if (err) + goto out; + /* Mark unused entries in inode bitmap used */ + bh = bclean(handle, sb, block); + if (IS_ERR(bh)) { + err = PTR_ERR(bh); + goto out; + } + + ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), + sb->s_blocksize * 8, bh->b_data); + err = ext4_handle_dirty_metadata(handle, NULL, bh); + brelse(bh); + if (err) + goto out; + } + + /* Mark group tables in block bitmap */ + for (j = 0; j < GROUP_TABLE_COUNT; j++) { + count = group_table_count[j]; + start = (&group_data[0].block_bitmap)[j]; + block = start; + for (i = 1; i < flex_gd->count; i++) { + block += group_table_count[j]; + if (block == (&group_data[i].block_bitmap)[j]) { + count += group_table_count[j]; + continue; + } + err = set_flexbg_block_bitmap(sb, handle, + flex_gd, + EXT4_B2C(sbi, start), + EXT4_B2C(sbi, + start + count + - 1)); + if (err) + goto out; + count = group_table_count[j]; + start = (&group_data[i].block_bitmap)[j]; + block = start; + } + + if (count) { + err = set_flexbg_block_bitmap(sb, handle, + flex_gd, + EXT4_B2C(sbi, start), + EXT4_B2C(sbi, + start + count + - 1)); + if (err) + goto out; + } + } + +out: + err2 = ext4_journal_stop(handle); + if (err2 && !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_feature_sparse_super(sb)) { + 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, + ext4_group_t end, + struct buffer_head *primary) +{ + const ext4_fsblk_t blk = primary->b_blocknr; + 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, "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, + ext4_group_t group) +{ + struct super_block *sb = inode->i_sb; + struct ext4_super_block *es = EXT4_SB(sb)->s_es; + unsigned long gdb_num = 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 = NULL; + struct buffer_head *dind = NULL; + struct buffer_head *gdb_bh = NULL; + int gdbackups; + struct ext4_iloc iloc = { .bh = NULL }; + __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); + + gdb_bh = ext4_sb_bread(sb, gdblock, 0); + if (IS_ERR(gdb_bh)) + return PTR_ERR(gdb_bh); + + gdbackups = verify_reserved_gdb(sb, group, gdb_bh); + if (gdbackups < 0) { + err = gdbackups; + goto errout; + } + + data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; + dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0); + if (IS_ERR(dind)) { + err = PTR_ERR(dind); + dind = NULL; + goto errout; + } + + data = (__le32 *)dind->b_data; + if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) { + ext4_warning(sb, "new group %u GDT block %llu not reserved", + group, gdblock); + err = -EINVAL; + goto errout; + } + + BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access"); + err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh); + if (unlikely(err)) + goto errout; + + BUFFER_TRACE(gdb_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, gdb_bh); + if (unlikely(err)) + goto errout; + + BUFFER_TRACE(dind, "get_write_access"); + err = ext4_journal_get_write_access(handle, dind); + if (unlikely(err)) { + ext4_std_error(sb, err); + goto errout; + } + + /* ext4_reserve_inode_write() gets a reference on the iloc */ + err = ext4_reserve_inode_write(handle, inode, &iloc); + if (unlikely(err)) + goto errout; + + n_group_desc = ext4_kvmalloc((gdb_num + 1) * + sizeof(struct buffer_head *), + GFP_NOFS); + if (!n_group_desc) { + err = -ENOMEM; + ext4_warning(sb, "not enough memory for %lu groups", + gdb_num + 1); + goto errout; + } + + /* + * 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; + err = ext4_handle_dirty_metadata(handle, NULL, dind); + if (unlikely(err)) { + ext4_std_error(sb, err); + goto errout; + } + inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> + (9 - EXT4_SB(sb)->s_cluster_bits); + ext4_mark_iloc_dirty(handle, inode, &iloc); + memset(gdb_bh->b_data, 0, sb->s_blocksize); + err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh); + if (unlikely(err)) { + ext4_std_error(sb, err); + iloc.bh = NULL; + goto errout; + } + brelse(dind); + + rcu_read_lock(); + o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc); + memcpy(n_group_desc, o_group_desc, + EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *)); + rcu_read_unlock(); + n_group_desc[gdb_num] = gdb_bh; + rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc); + EXT4_SB(sb)->s_gdb_count++; + ext4_kvfree_array_rcu(o_group_desc); + + le16_add_cpu(&es->s_reserved_gdt_blocks, -1); + err = ext4_handle_dirty_super(handle, sb); + if (err) + ext4_std_error(sb, err); + return err; +errout: + kvfree(n_group_desc); + brelse(iloc.bh); + brelse(dind); + brelse(gdb_bh); + + ext4_debug("leaving with error %d\n", err); + return err; +} + +/* + * add_new_gdb_meta_bg is the sister of add_new_gdb. + */ +static int add_new_gdb_meta_bg(struct super_block *sb, + handle_t *handle, ext4_group_t group) { + ext4_fsblk_t gdblock; + struct buffer_head *gdb_bh; + struct buffer_head **o_group_desc, **n_group_desc; + unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb); + int err; + + gdblock = ext4_meta_bg_first_block_no(sb, group) + + ext4_bg_has_super(sb, group); + gdb_bh = ext4_sb_bread(sb, gdblock, 0); + if (IS_ERR(gdb_bh)) + return PTR_ERR(gdb_bh); + n_group_desc = ext4_kvmalloc((gdb_num + 1) * + sizeof(struct buffer_head *), + GFP_NOFS); + if (!n_group_desc) { + brelse(gdb_bh); + err = -ENOMEM; + ext4_warning(sb, "not enough memory for %lu groups", + gdb_num + 1); + return err; + } + + rcu_read_lock(); + o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc); + memcpy(n_group_desc, o_group_desc, + EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *)); + rcu_read_unlock(); + n_group_desc[gdb_num] = gdb_bh; + + BUFFER_TRACE(gdb_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, gdb_bh); + if (err) { + kvfree(n_group_desc); + brelse(gdb_bh); + return err; + } + + rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc); + EXT4_SB(sb)->s_gdb_count++; + ext4_kvfree_array_rcu(o_group_desc); + 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, + ext4_group_t group) +{ + struct super_block *sb = inode->i_sb; + int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks); + int cluster_bits = EXT4_SB(sb)->s_cluster_bits; + 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_array(reserved_gdb, sizeof(*primary), GFP_NOFS); + if (!primary) + return -ENOMEM; + + data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK; + dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0); + if (IS_ERR(dind)) { + err = PTR_ERR(dind); + dind = NULL; + 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, "reserved block %llu" + " not at offset %ld", + blk, + (long)(data - (__le32 *)dind->b_data)); + err = -EINVAL; + goto exit_bh; + } + primary[res] = ext4_sb_bread(sb, blk, 0); + if (IS_ERR(primary[res])) { + err = PTR_ERR(primary[res]); + primary[res] = NULL; + goto exit_bh; + } + gdbackups = verify_reserved_gdb(sb, group, primary[res]); + if (gdbackups < 0) { + brelse(primary[res]); + err = gdbackups; + goto exit_bh; + } + if (++data >= end) + data = (__le32 *)dind->b_data; + } + + for (i = 0; i < reserved_gdb; i++) { + BUFFER_TRACE(primary[i], "get_write_access"); + if ((err = ext4_journal_get_write_access(handle, primary[i]))) + 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 = 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 - cluster_bits); + 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 take the s_resize_lock 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, sector_t blk_off, char *data, + int size, int meta_bg) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_group_t last; + const int bpg = EXT4_BLOCKS_PER_GROUP(sb); + unsigned three = 1; + unsigned five = 5; + unsigned seven = 7; + ext4_group_t group = 0; + int rest = sb->s_blocksize - size; + handle_t *handle; + int err = 0, err2; + + handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA); + if (IS_ERR(handle)) { + group = 1; + err = PTR_ERR(handle); + goto exit_err; + } + + if (meta_bg == 0) { + group = ext4_list_backups(sb, &three, &five, &seven); + last = sbi->s_groups_count; + } else { + group = ext4_get_group_number(sb, blk_off) + 1; + last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2); + } + + while (group < sbi->s_groups_count) { + struct buffer_head *bh; + ext4_fsblk_t backup_block; + + /* 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; + + if (meta_bg == 0) + backup_block = ((ext4_fsblk_t)group) * bpg + blk_off; + else + backup_block = (ext4_group_first_block_no(sb, group) + + ext4_bg_has_super(sb, group)); + + bh = sb_getblk(sb, backup_block); + if (unlikely(!bh)) { + err = -ENOMEM; + break; + } + ext4_debug("update metadata backup %llu(+%llu)\n", + backup_block, backup_block - + ext4_group_first_block_no(sb, group)); + BUFFER_TRACE(bh, "get_write_access"); + if ((err = ext4_journal_get_write_access(handle, bh))) { + brelse(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); + err = ext4_handle_dirty_metadata(handle, NULL, bh); + if (unlikely(err)) + ext4_std_error(sb, err); + brelse(bh); + + if (meta_bg == 0) + group = ext4_list_backups(sb, &three, &five, &seven); + else if (group == last) + break; + else + group = last; + } + 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, "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); + } +} + +/* + * ext4_add_new_descs() adds @count group descriptor of groups + * starting at @group + * + * @handle: journal handle + * @sb: super block + * @group: the group no. of the first group desc to be added + * @resize_inode: the resize inode + * @count: number of group descriptors to be added + */ +static int ext4_add_new_descs(handle_t *handle, struct super_block *sb, + ext4_group_t group, struct inode *resize_inode, + ext4_group_t count) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + struct buffer_head *gdb_bh; + int i, gdb_off, gdb_num, err = 0; + int meta_bg; + + meta_bg = ext4_has_feature_meta_bg(sb); + for (i = 0; i < count; i++, group++) { + int reserved_gdb = ext4_bg_has_super(sb, group) ? + le16_to_cpu(es->s_reserved_gdt_blocks) : 0; + + gdb_off = group % EXT4_DESC_PER_BLOCK(sb); + gdb_num = group / EXT4_DESC_PER_BLOCK(sb); + + /* + * 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) { + gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, + gdb_num); + BUFFER_TRACE(gdb_bh, "get_write_access"); + err = ext4_journal_get_write_access(handle, gdb_bh); + + if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group)) + err = reserve_backup_gdb(handle, resize_inode, group); + } else if (meta_bg != 0) { + err = add_new_gdb_meta_bg(sb, handle, group); + } else { + err = add_new_gdb(handle, resize_inode, group); + } + if (err) + break; + } + return err; +} + +static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block) +{ + struct buffer_head *bh = sb_getblk(sb, block); + if (unlikely(!bh)) + return NULL; + if (!bh_uptodate_or_lock(bh)) { + if (bh_submit_read(bh) < 0) { + brelse(bh); + return NULL; + } + } + + return bh; +} + +static int ext4_set_bitmap_checksums(struct super_block *sb, + ext4_group_t group, + struct ext4_group_desc *gdp, + struct ext4_new_group_data *group_data) +{ + struct buffer_head *bh; + + if (!ext4_has_metadata_csum(sb)) + return 0; + + bh = ext4_get_bitmap(sb, group_data->inode_bitmap); + if (!bh) + return -EIO; + ext4_inode_bitmap_csum_set(sb, group, gdp, bh, + EXT4_INODES_PER_GROUP(sb) / 8); + brelse(bh); + + bh = ext4_get_bitmap(sb, group_data->block_bitmap); + if (!bh) + return -EIO; + ext4_block_bitmap_csum_set(sb, group, gdp, bh); + brelse(bh); + + return 0; +} + +/* + * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg + */ +static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb, + struct ext4_new_flex_group_data *flex_gd) +{ + struct ext4_new_group_data *group_data = flex_gd->groups; + struct ext4_group_desc *gdp; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct buffer_head *gdb_bh; + ext4_group_t group; + __u16 *bg_flags = flex_gd->bg_flags; + int i, gdb_off, gdb_num, err = 0; + + + for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) { + group = group_data->group; + + gdb_off = group % EXT4_DESC_PER_BLOCK(sb); + gdb_num = group / EXT4_DESC_PER_BLOCK(sb); + + /* + * get_write_access() has been called on gdb_bh by ext4_add_new_desc(). + */ + gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num); + /* Update group descriptor block for new group */ + gdp = (struct ext4_group_desc *)(gdb_bh->b_data + + gdb_off * EXT4_DESC_SIZE(sb)); + + memset(gdp, 0, EXT4_DESC_SIZE(sb)); + ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap); + ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap); + err = ext4_set_bitmap_checksums(sb, group, gdp, group_data); + if (err) { + ext4_std_error(sb, err); + break; + } + + ext4_inode_table_set(sb, gdp, group_data->inode_table); + ext4_free_group_clusters_set(sb, gdp, + group_data->free_clusters_count); + ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb)); + if (ext4_has_group_desc_csum(sb)) + ext4_itable_unused_set(sb, gdp, + EXT4_INODES_PER_GROUP(sb)); + gdp->bg_flags = cpu_to_le16(*bg_flags); + ext4_group_desc_csum_set(sb, group, gdp); + + err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh); + if (unlikely(err)) { + ext4_std_error(sb, err); + break; + } + + /* + * We can allocate memory for mb_alloc based on the new group + * descriptor + */ + err = ext4_mb_add_groupinfo(sb, group, gdp); + if (err) + break; + } + return err; +} + +/* + * ext4_update_super() updates the super block so that the newly added + * groups can be seen by the filesystem. + * + * @sb: super block + * @flex_gd: new added groups + */ +static void ext4_update_super(struct super_block *sb, + struct ext4_new_flex_group_data *flex_gd) +{ + ext4_fsblk_t blocks_count = 0; + ext4_fsblk_t free_blocks = 0; + ext4_fsblk_t reserved_blocks = 0; + struct ext4_new_group_data *group_data = flex_gd->groups; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + int i; + + BUG_ON(flex_gd->count == 0 || group_data == NULL); + /* + * 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. + */ + for (i = 0; i < flex_gd->count; i++) { + blocks_count += group_data[i].blocks_count; + free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count); + } + + reserved_blocks = ext4_r_blocks_count(es) * 100; + reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es)); + reserved_blocks *= blocks_count; + do_div(reserved_blocks, 100); + + ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count); + ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks); + le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) * + flex_gd->count); + le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) * + flex_gd->count); + + ext4_debug("free blocks count %llu", ext4_free_blocks_count(es)); + /* + * We need to protect s_groups_count against other CPUs seeing + * inconsistent state in the superblock. + * + * The precise rules we use are: + * + * * Writers must perform a smp_wmb() after updating all + * dependent data and before modifying the groups count + * + * * 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 += flex_gd->count; + sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count, + (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb))); + + /* Update the reserved block counts only once the new group is + * active. */ + ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) + + reserved_blocks); + + /* Update the free space counts */ + percpu_counter_add(&sbi->s_freeclusters_counter, + EXT4_NUM_B2C(sbi, free_blocks)); + percpu_counter_add(&sbi->s_freeinodes_counter, + EXT4_INODES_PER_GROUP(sb) * flex_gd->count); + + ext4_debug("free blocks count %llu", + percpu_counter_read(&sbi->s_freeclusters_counter)); + if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) { + ext4_group_t flex_group; + struct flex_groups *fg; + + flex_group = ext4_flex_group(sbi, group_data[0].group); + fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group); + atomic64_add(EXT4_NUM_B2C(sbi, free_blocks), + &fg->free_clusters); + atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count, + &fg->free_inodes); + } + + /* + * Update the fs overhead information + */ + ext4_calculate_overhead(sb); + + if (test_opt(sb, DEBUG)) + printk(KERN_DEBUG "EXT4-fs: added group %u:" + "%llu blocks(%llu free %llu reserved)\n", flex_gd->count, + blocks_count, free_blocks, reserved_blocks); +} + +/* Add a flex group to an fs. 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. + */ +static int ext4_flex_group_add(struct super_block *sb, + struct inode *resize_inode, + struct ext4_new_flex_group_data *flex_gd) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + ext4_fsblk_t o_blocks_count; + ext4_grpblk_t last; + ext4_group_t group; + handle_t *handle; + unsigned reserved_gdb; + int err = 0, err2 = 0, credit; + + BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags); + + reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks); + o_blocks_count = ext4_blocks_count(es); + ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last); + BUG_ON(last); + + err = setup_new_flex_group_blocks(sb, flex_gd); + if (err) + goto exit; + /* + * We will always be modifying at least the superblock and GDT + * blocks. 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. + */ + credit = 3; /* sb, resize inode, resize inode dindirect */ + /* GDT blocks */ + credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb)); + credit += reserved_gdb; /* Reserved GDT dindirect blocks */ + handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + goto exit; + } + + BUFFER_TRACE(sbi->s_sbh, "get_write_access"); + err = ext4_journal_get_write_access(handle, sbi->s_sbh); + if (err) + goto exit_journal; + + group = flex_gd->groups[0].group; + BUG_ON(group != sbi->s_groups_count); + err = ext4_add_new_descs(handle, sb, group, + resize_inode, flex_gd->count); + if (err) + goto exit_journal; + + err = ext4_setup_new_descs(handle, sb, flex_gd); + if (err) + goto exit_journal; + + ext4_update_super(sb, flex_gd); + + err = ext4_handle_dirty_super(handle, sb); + +exit_journal: + err2 = ext4_journal_stop(handle); + if (!err) + err = err2; + + if (!err) { + int gdb_num = group / EXT4_DESC_PER_BLOCK(sb); + int gdb_num_end = ((group + flex_gd->count - 1) / + EXT4_DESC_PER_BLOCK(sb)); + int meta_bg = ext4_has_feature_meta_bg(sb); + sector_t old_gdb = 0; + + update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es, + sizeof(struct ext4_super_block), 0); + for (; gdb_num <= gdb_num_end; gdb_num++) { + struct buffer_head *gdb_bh; + + gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, + gdb_num); + if (old_gdb == gdb_bh->b_blocknr) + continue; + update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data, + gdb_bh->b_size, meta_bg); + old_gdb = gdb_bh->b_blocknr; + } + } +exit: + return err; +} + +static int ext4_setup_next_flex_gd(struct super_block *sb, + struct ext4_new_flex_group_data *flex_gd, + ext4_fsblk_t n_blocks_count, + unsigned long flexbg_size) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + struct ext4_new_group_data *group_data = flex_gd->groups; + ext4_fsblk_t o_blocks_count; + ext4_group_t n_group; + ext4_group_t group; + ext4_group_t last_group; + ext4_grpblk_t last; + ext4_grpblk_t clusters_per_group; + unsigned long i; + + clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb); + + o_blocks_count = ext4_blocks_count(es); + + if (o_blocks_count == n_blocks_count) + return 0; + + ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last); + BUG_ON(last); + ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last); + + last_group = group | (flexbg_size - 1); + if (last_group > n_group) + last_group = n_group; + + flex_gd->count = last_group - group + 1; + + for (i = 0; i < flex_gd->count; i++) { + int overhead; + + group_data[i].group = group + i; + group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb); + overhead = ext4_group_overhead_blocks(sb, group + i); + group_data[i].mdata_blocks = overhead; + group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb); + if (ext4_has_group_desc_csum(sb)) { + flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT | + EXT4_BG_INODE_UNINIT; + if (!test_opt(sb, INIT_INODE_TABLE)) + flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED; + } else + flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED; + } + + if (last_group == n_group && ext4_has_group_desc_csum(sb)) + /* We need to initialize block bitmap of last group. */ + flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT; + + if ((last_group == n_group) && (last != clusters_per_group - 1)) { + group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1); + group_data[i - 1].free_clusters_count -= clusters_per_group - + last - 1; + } + + return 1; +} + +/* 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_new_flex_group_data flex_gd; + 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 inode *inode = NULL; + int gdb_off; + int err; + __u16 bg_flags = 0; + + gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb); + + if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) { + ext4_warning(sb, "Can't resize non-sparse filesystem further"); + return -EPERM; + } + + if (ext4_blocks_count(es) + input->blocks_count < + ext4_blocks_count(es)) { + ext4_warning(sb, "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, "inodes_count overflow"); + return -EINVAL; + } + + if (reserved_gdb || gdb_off == 0) { + if (!ext4_has_feature_resize_inode(sb) || + !le16_to_cpu(es->s_reserved_gdt_blocks)) { + ext4_warning(sb, + "No reserved GDT blocks, can't resize"); + return -EPERM; + } + inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL); + if (IS_ERR(inode)) { + ext4_warning(sb, "Error opening resize inode"); + return PTR_ERR(inode); + } + } + + + err = verify_group_input(sb, input); + if (err) + goto out; + + err = ext4_alloc_flex_bg_array(sb, input->group + 1); + if (err) + goto out; + + err = ext4_mb_alloc_groupinfo(sb, input->group + 1); + if (err) + goto out; + + flex_gd.count = 1; + flex_gd.groups = input; + flex_gd.bg_flags = &bg_flags; + err = ext4_flex_group_add(sb, inode, &flex_gd); +out: + iput(inode); + return err; +} /* ext4_group_add */ + +/* + * extend a group without checking assuming that checking has been done. + */ +static int ext4_group_extend_no_check(struct super_block *sb, + ext4_fsblk_t o_blocks_count, ext4_grpblk_t add) +{ + struct ext4_super_block *es = EXT4_SB(sb)->s_es; + handle_t *handle; + int err = 0, err2; + + /* We will update the superblock, one block bitmap, and + * one group descriptor via ext4_group_add_blocks(). + */ + handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + ext4_warning(sb, "error %d on journal start", err); + return err; + } + + BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access"); + err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh); + if (err) { + ext4_warning(sb, "error %d on journal write access", err); + goto errout; + } + + ext4_blocks_count_set(es, o_blocks_count + add); + ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add); + 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 */ + err = ext4_group_add_blocks(handle, sb, o_blocks_count, add); + if (err) + goto errout; + ext4_handle_dirty_super(handle, sb); + ext4_debug("freed blocks %llu through %llu\n", o_blocks_count, + o_blocks_count + add); +errout: + err2 = ext4_journal_stop(handle); + if (err2 && !err) + err = err2; + + if (!err) { + 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), 0); + } + return err; +} + +/* + * 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=<size>" + * 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_grpblk_t last; + ext4_grpblk_t add; + struct buffer_head *bh; + int err; + ext4_group_t group; + + o_blocks_count = ext4_blocks_count(es); + + if (test_opt(sb, DEBUG)) + ext4_msg(sb, KERN_DEBUG, + "extending last group from %llu to %llu blocks", + 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)) { + ext4_msg(sb, KERN_ERR, + "filesystem too large to resize to %llu blocks safely", + n_blocks_count); + if (sizeof(sector_t) < 8) + ext4_warning(sb, "CONFIG_LBDAF not enabled"); + return -EINVAL; + } + + if (n_blocks_count < o_blocks_count) { + ext4_warning(sb, "can't shrink FS - resize aborted"); + return -EINVAL; + } + + /* 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, "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, "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, "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, "can't read last block, resize aborted"); + return -ENOSPC; + } + brelse(bh); + + err = ext4_group_extend_no_check(sb, o_blocks_count, add); + return err; +} /* ext4_group_extend */ + + +static int num_desc_blocks(struct super_block *sb, ext4_group_t groups) +{ + return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb); +} + +/* + * Release the resize inode and drop the resize_inode feature if there + * are no more reserved gdt blocks, and then convert the file system + * to enable meta_bg + */ +static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode) +{ + handle_t *handle; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + struct ext4_inode_info *ei = EXT4_I(inode); + ext4_fsblk_t nr; + int i, ret, err = 0; + int credits = 1; + + ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg"); + if (inode) { + if (es->s_reserved_gdt_blocks) { + ext4_error(sb, "Unexpected non-zero " + "s_reserved_gdt_blocks"); + return -EPERM; + } + + /* Do a quick sanity check of the resize inode */ + if (inode->i_blocks != 1 << (inode->i_blkbits - + (9 - sbi->s_cluster_bits))) + goto invalid_resize_inode; + for (i = 0; i < EXT4_N_BLOCKS; i++) { + if (i == EXT4_DIND_BLOCK) { + if (ei->i_data[i]) + continue; + else + goto invalid_resize_inode; + } + if (ei->i_data[i]) + goto invalid_resize_inode; + } + credits += 3; /* block bitmap, bg descriptor, resize inode */ + } + + handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + BUFFER_TRACE(sbi->s_sbh, "get_write_access"); + err = ext4_journal_get_write_access(handle, sbi->s_sbh); + if (err) + goto errout; + + ext4_clear_feature_resize_inode(sb); + ext4_set_feature_meta_bg(sb); + sbi->s_es->s_first_meta_bg = + cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count)); + + err = ext4_handle_dirty_super(handle, sb); + if (err) { + ext4_std_error(sb, err); + goto errout; + } + + if (inode) { + nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]); + ext4_free_blocks(handle, inode, NULL, nr, 1, + EXT4_FREE_BLOCKS_METADATA | + EXT4_FREE_BLOCKS_FORGET); + ei->i_data[EXT4_DIND_BLOCK] = 0; + inode->i_blocks = 0; + + err = ext4_mark_inode_dirty(handle, inode); + if (err) + ext4_std_error(sb, err); + } + +errout: + ret = ext4_journal_stop(handle); + if (!err) + err = ret; + return ret; + +invalid_resize_inode: + ext4_error(sb, "corrupted/inconsistent resize inode"); + return -EINVAL; +} + +/* + * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count + * + * @sb: super block of the fs to be resized + * @n_blocks_count: the number of blocks resides in the resized fs + */ +int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count) +{ + struct ext4_new_flex_group_data *flex_gd = NULL; + struct ext4_sb_info *sbi = EXT4_SB(sb); + struct ext4_super_block *es = sbi->s_es; + struct buffer_head *bh; + struct inode *resize_inode = NULL; + ext4_grpblk_t add, offset; + unsigned long n_desc_blocks; + unsigned long o_desc_blocks; + ext4_group_t o_group; + ext4_group_t n_group; + ext4_fsblk_t o_blocks_count; + ext4_fsblk_t n_blocks_count_retry = 0; + unsigned long last_update_time = 0; + int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex; + int meta_bg; + + /* See if the device is actually as big as what was requested */ + bh = sb_bread(sb, n_blocks_count - 1); + if (!bh) { + ext4_warning(sb, "can't read last block, resize aborted"); + return -ENOSPC; + } + brelse(bh); + +retry: + o_blocks_count = ext4_blocks_count(es); + + ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu " + "to %llu blocks", o_blocks_count, n_blocks_count); + + if (n_blocks_count < o_blocks_count) { + /* On-line shrinking not supported */ + ext4_warning(sb, "can't shrink FS - resize aborted"); + return -EINVAL; + } + + if (n_blocks_count == o_blocks_count) + /* Nothing need to do */ + return 0; + + n_group = ext4_get_group_number(sb, n_blocks_count - 1); + if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) { + ext4_warning(sb, "resize would cause inodes_count overflow"); + return -EINVAL; + } + ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset); + + n_desc_blocks = num_desc_blocks(sb, n_group + 1); + o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count); + + meta_bg = ext4_has_feature_meta_bg(sb); + + if (ext4_has_feature_resize_inode(sb)) { + if (meta_bg) { + ext4_error(sb, "resize_inode and meta_bg enabled " + "simultaneously"); + return -EINVAL; + } + if (n_desc_blocks > o_desc_blocks + + le16_to_cpu(es->s_reserved_gdt_blocks)) { + n_blocks_count_retry = n_blocks_count; + n_desc_blocks = o_desc_blocks + + le16_to_cpu(es->s_reserved_gdt_blocks); + n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb); + n_blocks_count = (ext4_fsblk_t)n_group * + EXT4_BLOCKS_PER_GROUP(sb) + + le32_to_cpu(es->s_first_data_block); + n_group--; /* set to last group number */ + } + + if (!resize_inode) + resize_inode = ext4_iget(sb, EXT4_RESIZE_INO, + EXT4_IGET_SPECIAL); + if (IS_ERR(resize_inode)) { + ext4_warning(sb, "Error opening resize inode"); + return PTR_ERR(resize_inode); + } + } + + if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) { + err = ext4_convert_meta_bg(sb, resize_inode); + if (err) + goto out; + if (resize_inode) { + iput(resize_inode); + resize_inode = NULL; + } + if (n_blocks_count_retry) { + n_blocks_count = n_blocks_count_retry; + n_blocks_count_retry = 0; + goto retry; + } + } + + /* + * Make sure the last group has enough space so that it's + * guaranteed to have enough space for all metadata blocks + * that it might need to hold. (We might not need to store + * the inode table blocks in the last block group, but there + * will be cases where this might be needed.) + */ + if ((ext4_group_first_block_no(sb, n_group) + + ext4_group_overhead_blocks(sb, n_group) + 2 + + sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) { + n_blocks_count = ext4_group_first_block_no(sb, n_group); + n_group--; + n_blocks_count_retry = 0; + if (resize_inode) { + iput(resize_inode); + resize_inode = NULL; + } + goto retry; + } + + /* extend the last group */ + if (n_group == o_group) + add = n_blocks_count - o_blocks_count; + else + add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1)); + if (add > 0) { + err = ext4_group_extend_no_check(sb, o_blocks_count, add); + if (err) + goto out; + } + + if (ext4_blocks_count(es) == n_blocks_count) + goto out; + + err = ext4_alloc_flex_bg_array(sb, n_group + 1); + if (err) + goto out; + + err = ext4_mb_alloc_groupinfo(sb, n_group + 1); + if (err) + goto out; + + flex_gd = alloc_flex_gd(flexbg_size); + if (flex_gd == NULL) { + err = -ENOMEM; + goto out; + } + + /* Add flex groups. Note that a regular group is a + * flex group with 1 group. + */ + while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count, + flexbg_size)) { + if (jiffies - last_update_time > HZ * 10) { + if (last_update_time) + ext4_msg(sb, KERN_INFO, + "resized to %llu blocks", + ext4_blocks_count(es)); + last_update_time = jiffies; + } + if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0) + break; + err = ext4_flex_group_add(sb, resize_inode, flex_gd); + if (unlikely(err)) + break; + } + + if (!err && n_blocks_count_retry) { + n_blocks_count = n_blocks_count_retry; + n_blocks_count_retry = 0; + free_flex_gd(flex_gd); + flex_gd = NULL; + if (resize_inode) { + iput(resize_inode); + resize_inode = NULL; + } + goto retry; + } + +out: + if (flex_gd) + free_flex_gd(flex_gd); + if (resize_inode != NULL) + iput(resize_inode); + if (err) + ext4_warning(sb, "error (%d) occurred during " + "file system resize", err); + ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", + ext4_blocks_count(es)); + return err; +} |