+++ /dev/null
-/*
- * linux/fs/ext3/resize.c
- *
- * Support for resizing an ext3 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 EXT3FS_DEBUG
-
-#include "ext3.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 ext3_new_group_data *input)
-{
- struct ext3_sb_info *sbi = EXT3_SB(sb);
- struct ext3_super_block *es = sbi->s_es;
- ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
- ext3_fsblk_t end = start + input->blocks_count;
- unsigned group = input->group;
- ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
- unsigned overhead = ext3_bg_has_super(sb, group) ?
- (1 + ext3_bg_num_gdb(sb, group) +
- le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
- ext3_fsblk_t metaend = start + overhead;
- struct buffer_head *bh = NULL;
- ext3_grpblk_t free_blocks_count;
- 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 "EXT3-fs: adding %s group %u: %u blocks "
- "(%d free, %u reserved)\n",
- ext3_bg_has_super(sb, input->group) ? "normal" :
- "no-super", input->group, input->blocks_count,
- free_blocks_count, input->reserved_blocks);
-
- if (group != sbi->s_groups_count)
- ext3_warning(sb, __func__,
- "Cannot add at group %u (only %lu groups)",
- input->group, sbi->s_groups_count);
- else if ((start - le32_to_cpu(es->s_first_data_block)) %
- EXT3_BLOCKS_PER_GROUP(sb))
- ext3_warning(sb, __func__, "Last group not full");
- else if (input->reserved_blocks > input->blocks_count / 5)
- ext3_warning(sb, __func__, "Reserved blocks too high (%u)",
- input->reserved_blocks);
- else if (free_blocks_count < 0)
- ext3_warning(sb, __func__, "Bad blocks count %u",
- input->blocks_count);
- else if (!(bh = sb_bread(sb, end - 1)))
- ext3_warning(sb, __func__,
- "Cannot read last block ("E3FSBLK")",
- end - 1);
- else if (outside(input->block_bitmap, start, end))
- ext3_warning(sb, __func__,
- "Block bitmap not in group (block %u)",
- input->block_bitmap);
- else if (outside(input->inode_bitmap, start, end))
- ext3_warning(sb, __func__,
- "Inode bitmap not in group (block %u)",
- input->inode_bitmap);
- else if (outside(input->inode_table, start, end) ||
- outside(itend - 1, start, end))
- ext3_warning(sb, __func__,
- "Inode table not in group (blocks %u-"E3FSBLK")",
- input->inode_table, itend - 1);
- else if (input->inode_bitmap == input->block_bitmap)
- ext3_warning(sb, __func__,
- "Block bitmap same as inode bitmap (%u)",
- input->block_bitmap);
- else if (inside(input->block_bitmap, input->inode_table, itend))
- ext3_warning(sb, __func__,
- "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
- input->block_bitmap, input->inode_table, itend-1);
- else if (inside(input->inode_bitmap, input->inode_table, itend))
- ext3_warning(sb, __func__,
- "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
- input->inode_bitmap, input->inode_table, itend-1);
- else if (inside(input->block_bitmap, start, metaend))
- ext3_warning(sb, __func__,
- "Block bitmap (%u) in GDT table"
- " ("E3FSBLK"-"E3FSBLK")",
- input->block_bitmap, start, metaend - 1);
- else if (inside(input->inode_bitmap, start, metaend))
- ext3_warning(sb, __func__,
- "Inode bitmap (%u) in GDT table"
- " ("E3FSBLK"-"E3FSBLK")",
- input->inode_bitmap, start, metaend - 1);
- else if (inside(input->inode_table, start, metaend) ||
- inside(itend - 1, start, metaend))
- ext3_warning(sb, __func__,
- "Inode table (%u-"E3FSBLK") overlaps"
- "GDT table ("E3FSBLK"-"E3FSBLK")",
- 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,
- ext3_fsblk_t blk)
-{
- struct buffer_head *bh;
- int err;
-
- bh = sb_getblk(sb, blk);
- if (unlikely(!bh))
- return ERR_PTR(-ENOMEM);
- if ((err = ext3_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;
-}
-
-/*
- * To avoid calling the atomic setbit hundreds or thousands of times, we only
- * need to use it within a single byte (to ensure we get endianness right).
- * We can use memset for the rest of the bitmap as there are no other users.
- */
-static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
-{
- int i;
-
- if (start_bit >= end_bit)
- return;
-
- ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
- for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
- ext3_set_bit(i, bitmap);
- if (i < end_bit)
- memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
-}
-
-/*
- * If we have fewer than thresh credits, extend by EXT3_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 (handle->h_buffer_credits >= thresh)
- return 0;
-
- err = ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA);
- if (err < 0)
- return err;
- if (err) {
- err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA);
- if (err)
- return err;
- err = ext3_journal_get_write_access(handle, bh);
- if (err)
- 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 ext3_new_group_data *input)
-{
- struct ext3_sb_info *sbi = EXT3_SB(sb);
- ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
- int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
- le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
- unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
- struct buffer_head *bh;
- handle_t *handle;
- ext3_fsblk_t block;
- ext3_grpblk_t bit;
- int i;
- int err = 0, err2;
-
- /* This transaction may be extended/restarted along the way */
- handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
-
- if (IS_ERR(handle))
- return PTR_ERR(handle);
-
- mutex_lock(&sbi->s_resize_lock);
- 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 (ext3_bg_has_super(sb, input->group)) {
- ext3_debug("mark backup superblock %#04lx (+0)\n", start);
- ext3_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;
-
- ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
-
- err = extend_or_restart_transaction(handle, 1, bh);
- if (err)
- goto exit_bh;
-
- gdb = sb_getblk(sb, block);
- if (unlikely(!gdb)) {
- err = -ENOMEM;
- goto exit_bh;
- }
- if ((err = ext3_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);
- err = ext3_journal_dirty_metadata(handle, gdb);
- if (err) {
- brelse(gdb);
- goto exit_bh;
- }
- ext3_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;
-
- ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
-
- err = extend_or_restart_transaction(handle, 1, bh);
- if (err)
- goto exit_bh;
-
- if (IS_ERR(gdb = bclean(handle, sb, block))) {
- err = PTR_ERR(gdb);
- goto exit_bh;
- }
- err = ext3_journal_dirty_metadata(handle, gdb);
- if (err) {
- brelse(gdb);
- goto exit_bh;
- }
- ext3_set_bit(bit, bh->b_data);
- brelse(gdb);
- }
- ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
- input->block_bitmap - start);
- ext3_set_bit(input->block_bitmap - start, bh->b_data);
- ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
- input->inode_bitmap - start);
- ext3_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;
-
- ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
-
- err = extend_or_restart_transaction(handle, 1, bh);
- if (err)
- goto exit_bh;
-
- if (IS_ERR(it = bclean(handle, sb, block))) {
- err = PTR_ERR(it);
- goto exit_bh;
- }
- err = ext3_journal_dirty_metadata(handle, it);
- if (err) {
- brelse(it);
- goto exit_bh;
- }
- brelse(it);
- ext3_set_bit(bit, bh->b_data);
- }
-
- err = extend_or_restart_transaction(handle, 2, bh);
- if (err)
- goto exit_bh;
-
- mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
- bh->b_data);
- err = ext3_journal_dirty_metadata(handle, bh);
- if (err)
- goto exit_bh;
- brelse(bh);
-
- /* Mark unused entries in inode bitmap used */
- ext3_debug("clear inode bitmap %#04x (+%ld)\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(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
- bh->b_data);
- err = ext3_journal_dirty_metadata(handle, bh);
-exit_bh:
- brelse(bh);
-
-exit_journal:
- mutex_unlock(&sbi->s_resize_lock);
- if ((err2 = ext3_journal_stop(handle)) && !err)
- err = err2;
-
- return err;
-}
-
-/*
- * Iterate through the groups which hold BACKUP superblock/GDT copies in an
- * ext3 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 ext3_list_backups(struct super_block *sb, unsigned *three,
- unsigned *five, unsigned *seven)
-{
- unsigned *min = three;
- int mult = 3;
- unsigned ret;
-
- if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
- EXT3_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 ext3_fsblk_t blk = primary->b_blocknr;
- const unsigned long end = EXT3_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 = ext3_list_backups(sb, &three, &five, &seven)) < end) {
- if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
- ext3_warning(sb, __func__,
- "reserved GDT "E3FSBLK
- " missing grp %d ("E3FSBLK")",
- blk, grp,
- grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
- return -EINVAL;
- }
- if (++gdbackups > EXT3_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 ext3_new_group_data *input,
- struct buffer_head **primary)
-{
- struct super_block *sb = inode->i_sb;
- struct ext3_super_block *es = EXT3_SB(sb)->s_es;
- unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
- ext3_fsblk_t gdblock = EXT3_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 ext3_iloc iloc;
- __le32 *data;
- int err;
-
- if (test_opt(sb, DEBUG))
- printk(KERN_DEBUG
- "EXT3-fs: ext3_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 (EXT3_SB(sb)->s_sbh->b_blocknr !=
- le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
- ext3_warning(sb, __func__,
- "won't resize using backup superblock at %llu",
- (unsigned long long)EXT3_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 = EXT3_I(inode)->i_data + EXT3_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 % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
- ext3_warning(sb, __func__,
- "new group %u GDT block "E3FSBLK" not reserved",
- input->group, gdblock);
- err = -EINVAL;
- goto exit_dind;
- }
-
- if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
- goto exit_dind;
-
- if ((err = ext3_journal_get_write_access(handle, *primary)))
- goto exit_sbh;
-
- if ((err = ext3_journal_get_write_access(handle, dind)))
- goto exit_primary;
-
- /* ext3_reserve_inode_write() gets a reference on the iloc */
- if ((err = ext3_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;
- ext3_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 % EXT3_ADDR_PER_BLOCK(sb)] = 0;
- err = ext3_journal_dirty_metadata(handle, dind);
- if (err)
- goto exit_group_desc;
- brelse(dind);
- dind = NULL;
- inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
- err = ext3_mark_iloc_dirty(handle, inode, &iloc);
- if (err)
- goto exit_group_desc;
- memset((*primary)->b_data, 0, sb->s_blocksize);
- err = ext3_journal_dirty_metadata(handle, *primary);
- if (err)
- goto exit_group_desc;
-
- o_group_desc = EXT3_SB(sb)->s_group_desc;
- memcpy(n_group_desc, o_group_desc,
- EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
- n_group_desc[gdb_num] = *primary;
- EXT3_SB(sb)->s_group_desc = n_group_desc;
- EXT3_SB(sb)->s_gdb_count++;
- kfree(o_group_desc);
-
- le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
- err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
- if (err)
- goto exit_inode;
-
- return 0;
-
-exit_group_desc:
- kfree(n_group_desc);
-exit_inode:
- //ext3_journal_release_buffer(handle, iloc.bh);
- brelse(iloc.bh);
-exit_dindj:
- //ext3_journal_release_buffer(handle, dind);
-exit_primary:
- //ext3_journal_release_buffer(handle, *primary);
-exit_sbh:
- //ext3_journal_release_buffer(handle, *primary);
-exit_dind:
- brelse(dind);
-exit_bh:
- brelse(*primary);
-
- ext3_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 ext3_new_group_data *input)
-{
- struct super_block *sb = inode->i_sb;
- int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
- struct buffer_head **primary;
- struct buffer_head *dind;
- struct ext3_iloc iloc;
- ext3_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 = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
- dind = sb_bread(sb, le32_to_cpu(*data));
- if (!dind) {
- err = -EIO;
- goto exit_free;
- }
-
- blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
- data = (__le32 *)dind->b_data + (EXT3_SB(sb)->s_gdb_count %
- EXT3_ADDR_PER_BLOCK(sb));
- end = (__le32 *)dind->b_data + EXT3_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) {
- ext3_warning(sb, __func__,
- "reserved block "E3FSBLK
- " 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 = ext3_journal_get_write_access(handle, primary[i]))) {
- /*
- int j;
- for (j = 0; j < i; j++)
- ext3_journal_release_buffer(handle, primary[j]);
- */
- goto exit_bh;
- }
- }
-
- if ((err = ext3_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 * EXT3_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 = ext3_journal_dirty_metadata(handle, primary[i]);
- if (!err)
- err = err2;
- }
- inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
- ext3_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 ext3 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,
- int blk_off, char *data, int size)
-{
- struct ext3_sb_info *sbi = EXT3_SB(sb);
- const unsigned long last = sbi->s_groups_count;
- const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
- unsigned three = 1;
- unsigned five = 5;
- unsigned seven = 7;
- unsigned group;
- int rest = sb->s_blocksize - size;
- handle_t *handle;
- int err = 0, err2;
-
- handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
- if (IS_ERR(handle)) {
- group = 1;
- err = PTR_ERR(handle);
- goto exit_err;
- }
-
- while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
- struct buffer_head *bh;
-
- /* Out of journal space, and can't get more - abort - so sad */
- if (handle->h_buffer_credits == 0 &&
- ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
- (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
- break;
-
- bh = sb_getblk(sb, group * bpg + blk_off);
- if (unlikely(!bh)) {
- err = -ENOMEM;
- break;
- }
- ext3_debug("update metadata backup %#04lx\n",
- (unsigned long)bh->b_blocknr);
- if ((err = ext3_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 = ext3_journal_dirty_metadata(handle, bh);
- brelse(bh);
- if (err)
- break;
- }
- if ((err2 = ext3_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) {
- ext3_warning(sb, __func__,
- "can't update backup for group %d (err %d), "
- "forcing fsck on next reboot", group, err);
- sbi->s_mount_state &= ~EXT3_VALID_FS;
- sbi->s_es->s_state &= cpu_to_le16(~EXT3_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 ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
-{
- struct ext3_sb_info *sbi = EXT3_SB(sb);
- struct ext3_super_block *es = sbi->s_es;
- int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
- le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
- struct buffer_head *primary = NULL;
- struct ext3_group_desc *gdp;
- struct inode *inode = NULL;
- handle_t *handle;
- int gdb_off, gdb_num;
- int err, err2;
-
- gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
- gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
-
- if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
- EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
- ext3_warning(sb, __func__,
- "Can't resize non-sparse filesystem further");
- return -EPERM;
- }
-
- if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
- le32_to_cpu(es->s_blocks_count)) {
- ext3_warning(sb, __func__, "blocks_count overflow\n");
- return -EINVAL;
- }
-
- if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
- le32_to_cpu(es->s_inodes_count)) {
- ext3_warning(sb, __func__, "inodes_count overflow\n");
- return -EINVAL;
- }
-
- if (reserved_gdb || gdb_off == 0) {
- if (!EXT3_HAS_COMPAT_FEATURE(sb,
- EXT3_FEATURE_COMPAT_RESIZE_INODE)
- || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
- ext3_warning(sb, __func__,
- "No reserved GDT blocks, can't resize");
- return -EPERM;
- }
- inode = ext3_iget(sb, EXT3_RESIZE_INO);
- if (IS_ERR(inode)) {
- ext3_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 = ext3_journal_start_sb(sb,
- ext3_bg_has_super(sb, input->group) ?
- 3 + reserved_gdb : 4);
- if (IS_ERR(handle)) {
- err = PTR_ERR(handle);
- goto exit_put;
- }
-
- mutex_lock(&sbi->s_resize_lock);
- if (input->group != sbi->s_groups_count) {
- ext3_warning(sb, __func__,
- "multiple resizers run on filesystem!");
- err = -EBUSY;
- goto exit_journal;
- }
-
- if ((err = ext3_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 = ext3_journal_get_write_access(handle, primary)))
- goto exit_journal;
-
- if (reserved_gdb && ext3_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.
- *
- * We do not lock all allocations via s_resize_lock
- * 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.
- */
-
- /* Update group descriptor block for new group */
- gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
-
- gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
- gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
- gdp->bg_inode_table = cpu_to_le32(input->inode_table);
- gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
- gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
-
- /*
- * 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.
- */
- le32_add_cpu(&es->s_blocks_count, input->blocks_count);
- le32_add_cpu(&es->s_inodes_count, EXT3_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 s_resize_lock
- * AND
- * * Writers must perform a smp_wmb() after updating all dependent
- * data and before modifying the groups count
- *
- * * Readers must hold s_resize_lock 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++;
-
- err = ext3_journal_dirty_metadata(handle, primary);
- if (err)
- goto exit_journal;
-
- /* Update the reserved block counts only once the new group is
- * active. */
- le32_add_cpu(&es->s_r_blocks_count, 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,
- EXT3_INODES_PER_GROUP(sb));
-
- err = ext3_journal_dirty_metadata(handle, sbi->s_sbh);
-
-exit_journal:
- mutex_unlock(&sbi->s_resize_lock);
- if ((err2 = ext3_journal_stop(handle)) && !err)
- err = err2;
- if (!err) {
- update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
- sizeof(struct ext3_super_block));
- update_backups(sb, primary->b_blocknr, primary->b_data,
- primary->b_size);
- }
-exit_put:
- iput(inode);
- return err;
-} /* ext3_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=<size>"
- * for emergencies (because it has no dependencies on reserved blocks).
- *
- * If we _really_ wanted, we could use default values to call ext3_group_add()
- * allow the "remount" trick to work for arbitrary resizing, assuming enough
- * GDT blocks are reserved to grow to the desired size.
- */
-int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
- ext3_fsblk_t n_blocks_count)
-{
- ext3_fsblk_t o_blocks_count;
- ext3_grpblk_t last;
- ext3_grpblk_t add;
- struct buffer_head * bh;
- handle_t *handle;
- int err;
- unsigned long freed_blocks;
-
- /* We don't need to worry about locking wrt other resizers just
- * yet: we're going to revalidate es->s_blocks_count after
- * taking the s_resize_lock below. */
- o_blocks_count = le32_to_cpu(es->s_blocks_count);
-
- if (test_opt(sb, DEBUG))
- printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK
- " up to "E3FSBLK" 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 "EXT3-fs: filesystem on %s:"
- " too large to resize to "E3FSBLK" blocks safely\n",
- sb->s_id, n_blocks_count);
- if (sizeof(sector_t) < 8)
- ext3_warning(sb, __func__,
- "CONFIG_LBDAF not enabled\n");
- return -EINVAL;
- }
-
- if (n_blocks_count < o_blocks_count) {
- ext3_warning(sb, __func__,
- "can't shrink FS - resize aborted");
- return -EBUSY;
- }
-
- /* Handle the remaining blocks in the last group only. */
- last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
- EXT3_BLOCKS_PER_GROUP(sb);
-
- if (last == 0) {
- ext3_warning(sb, __func__,
- "need to use ext2online to resize further");
- return -EPERM;
- }
-
- add = EXT3_BLOCKS_PER_GROUP(sb) - last;
-
- if (o_blocks_count + add < o_blocks_count) {
- ext3_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)
- ext3_warning(sb, __func__,
- "will only finish group ("E3FSBLK
- " 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) {
- ext3_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 ext3_free_blocks().
- */
- handle = ext3_journal_start_sb(sb, 3);
- if (IS_ERR(handle)) {
- err = PTR_ERR(handle);
- ext3_warning(sb, __func__, "error %d on journal start",err);
- goto exit_put;
- }
-
- mutex_lock(&EXT3_SB(sb)->s_resize_lock);
- if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
- ext3_warning(sb, __func__,
- "multiple resizers run on filesystem!");
- mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
- ext3_journal_stop(handle);
- err = -EBUSY;
- goto exit_put;
- }
-
- if ((err = ext3_journal_get_write_access(handle,
- EXT3_SB(sb)->s_sbh))) {
- ext3_warning(sb, __func__,
- "error %d on journal write access", err);
- mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
- ext3_journal_stop(handle);
- goto exit_put;
- }
- es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
- err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
- mutex_unlock(&EXT3_SB(sb)->s_resize_lock);
- if (err) {
- ext3_warning(sb, __func__,
- "error %d on journal dirty metadata", err);
- ext3_journal_stop(handle);
- goto exit_put;
- }
- ext3_debug("freeing blocks "E3FSBLK" through "E3FSBLK"\n",
- o_blocks_count, o_blocks_count + add);
- ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
- ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n",
- o_blocks_count, o_blocks_count + add);
- if ((err = ext3_journal_stop(handle)))
- goto exit_put;
- if (test_opt(sb, DEBUG))
- printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
- le32_to_cpu(es->s_blocks_count));
- update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
- sizeof(struct ext3_super_block));
-exit_put:
- return err;
-} /* ext3_group_extend */
Code Review / kvmfornfv.git / blobdiff