| /* |
| * resize2fs.c --- ext2 main routine |
| * |
| * Copyright (C) 1997 Theodore Ts'o |
| * |
| * %Begin-Header% |
| * All rights reserved. |
| * %End-Header% |
| */ |
| |
| #include "resize2fs.h" |
| |
| /* |
| * This routine adjusts the superblock and other data structures... |
| */ |
| static errcode_t adjust_superblock(ext2_resize_t rfs, blk_t new_size) |
| { |
| ext2_filsys fs; |
| int overhead = 0; |
| int rem; |
| errcode_t retval; |
| ino_t real_end; |
| blk_t blk, group_block; |
| unsigned long i, j; |
| struct ext2_group_desc *new; |
| char *buf; |
| int old_numblocks, numblocks, adjblocks; |
| |
| fs = rfs->new_fs; |
| fs->super->s_blocks_count = new_size; |
| ext2fs_mark_super_dirty(fs); |
| ext2fs_mark_bb_dirty(fs); |
| ext2fs_mark_ib_dirty(fs); |
| |
| retry: |
| fs->group_desc_count = (fs->super->s_blocks_count - |
| fs->super->s_first_data_block + |
| EXT2_BLOCKS_PER_GROUP(fs->super) - 1) |
| / EXT2_BLOCKS_PER_GROUP(fs->super); |
| if (fs->group_desc_count == 0) |
| return EXT2_ET_TOOSMALL; |
| fs->desc_blocks = (fs->group_desc_count + |
| EXT2_DESC_PER_BLOCK(fs->super) - 1) |
| / EXT2_DESC_PER_BLOCK(fs->super); |
| |
| /* |
| * Overhead is the number of bookkeeping blocks per group. It |
| * includes the superblock backup, the group descriptor |
| * backups, the inode bitmap, the block bitmap, and the inode |
| * table. |
| * |
| * XXX Not all block groups need the descriptor blocks, but |
| * being clever is tricky... |
| */ |
| overhead = 3 + fs->desc_blocks + fs->inode_blocks_per_group; |
| |
| /* |
| * See if the last group is big enough to support the |
| * necessary data structures. If not, we need to get rid of |
| * it. |
| */ |
| rem = (fs->super->s_blocks_count - fs->super->s_first_data_block) % |
| fs->super->s_blocks_per_group; |
| if ((fs->group_desc_count == 1) && rem && (rem < overhead)) |
| return EXT2_ET_TOOSMALL; |
| if (rem && (rem < overhead+50)) { |
| fs->super->s_blocks_count -= rem; |
| goto retry; |
| } |
| /* |
| * Adjust the number of inodes |
| */ |
| fs->super->s_inodes_count = fs->super->s_inodes_per_group * |
| fs->group_desc_count; |
| |
| /* |
| * Adjust the number of free blocks |
| */ |
| blk = rfs->old_fs->super->s_blocks_count; |
| if (blk > fs->super->s_blocks_count) |
| fs->super->s_free_blocks_count -= |
| (blk - fs->super->s_blocks_count); |
| else |
| fs->super->s_free_blocks_count += |
| (fs->super->s_blocks_count - blk); |
| |
| /* |
| * Adjust the bitmaps for size |
| */ |
| retval = ext2fs_resize_inode_bitmap(fs->super->s_inodes_count, |
| fs->super->s_inodes_count, |
| fs->inode_map); |
| if (retval) |
| return retval; |
| |
| real_end = ((EXT2_BLOCKS_PER_GROUP(fs->super) |
| * fs->group_desc_count)) - 1 + |
| fs->super->s_first_data_block; |
| retval = ext2fs_resize_block_bitmap(fs->super->s_blocks_count-1, |
| real_end, fs->block_map); |
| |
| if (retval) |
| return retval; |
| |
| /* |
| * Reallocate the group descriptors as necessary. |
| */ |
| if (rfs->old_fs->desc_blocks != fs->desc_blocks) { |
| new = realloc(fs->group_desc, |
| fs->desc_blocks * fs->blocksize); |
| if (!new) |
| return ENOMEM; |
| fs->group_desc = new; |
| } |
| |
| /* |
| * Fix the count of the last (old) block group |
| */ |
| if (rfs->old_fs->group_desc_count > fs->group_desc_count) |
| return 0; |
| old_numblocks = (rfs->old_fs->super->s_blocks_count - |
| rfs->old_fs->super->s_first_data_block) % |
| rfs->old_fs->super->s_blocks_per_group; |
| if (!old_numblocks) |
| old_numblocks = rfs->old_fs->super->s_blocks_per_group; |
| if (rfs->old_fs->group_desc_count == fs->group_desc_count) { |
| numblocks = (rfs->new_fs->super->s_blocks_count - |
| rfs->new_fs->super->s_first_data_block) % |
| rfs->new_fs->super->s_blocks_per_group; |
| if (!numblocks) |
| numblocks = rfs->new_fs->super->s_blocks_per_group; |
| } else |
| numblocks = rfs->new_fs->super->s_blocks_per_group; |
| i = rfs->old_fs->group_desc_count - 1; |
| fs->group_desc[i].bg_free_blocks_count += (numblocks-old_numblocks); |
| |
| /* |
| * Initialize the new block group descriptors |
| */ |
| if (rfs->old_fs->group_desc_count >= fs->group_desc_count) |
| return 0; |
| buf = malloc(fs->blocksize); |
| if (!buf) |
| return ENOMEM; |
| memset(buf, 0, fs->blocksize); |
| group_block = fs->super->s_first_data_block + |
| rfs->old_fs->group_desc_count * fs->super->s_blocks_per_group; |
| for (i = rfs->old_fs->group_desc_count; |
| i < fs->group_desc_count; i++) { |
| memset(&fs->group_desc[i], 0, |
| sizeof(struct ext2_group_desc)); |
| adjblocks = 0; |
| |
| if (i == fs->group_desc_count-1) { |
| numblocks = (fs->super->s_blocks_count - |
| fs->super->s_first_data_block) % |
| fs->super->s_blocks_per_group; |
| if (!numblocks) |
| numblocks = fs->super->s_blocks_per_group; |
| } else |
| numblocks = fs->super->s_blocks_per_group; |
| |
| if (ext2fs_bg_has_super(fs, i)) { |
| for (j=0; j < fs->desc_blocks+1; j++) |
| ext2fs_mark_block_bitmap(fs->block_map, |
| group_block + j); |
| adjblocks = 1 + fs->desc_blocks; |
| } |
| adjblocks += 2 + fs->inode_blocks_per_group; |
| |
| numblocks -= adjblocks; |
| fs->super->s_free_blocks_count -= adjblocks; |
| fs->super->s_free_inodes_count += |
| fs->super->s_inodes_per_group; |
| fs->group_desc[i].bg_free_blocks_count = numblocks; |
| fs->group_desc[i].bg_free_inodes_count = |
| fs->super->s_inodes_per_group; |
| fs->group_desc[i].bg_used_dirs_count = 0; |
| |
| retval = ext2fs_allocate_group_table(fs, i, 0); |
| if (retval) |
| return retval; |
| |
| for (blk=fs->group_desc[i].bg_inode_table, j=0; |
| j < fs->inode_blocks_per_group; |
| blk++, j++) { |
| retval = io_channel_write_blk(fs->io, blk, 1, buf); |
| if (retval) |
| return retval; |
| } |
| group_block += fs->super->s_blocks_per_group; |
| } |
| return 0; |
| } |
| |
| /* |
| * This routine marks and unmarks reserved blocks in the new block |
| * bitmap. It also determines which blocks need to be moved and |
| * places this information into the move_blocks bitmap. |
| */ |
| static errcode_t determine_relocations(ext2_resize_t rfs) |
| { |
| int i, j, max, adj; |
| blk_t blk, group_blk; |
| unsigned long old_blocks, new_blocks; |
| errcode_t retval; |
| ext2_filsys fs = rfs->new_fs; |
| |
| retval = ext2fs_allocate_block_bitmap(rfs->old_fs, |
| "blocks to be moved", |
| &rfs->reserve_blocks); |
| if (retval) |
| return retval; |
| |
| /* |
| * If we're shrinking the filesystem, we need to move all of |
| * the blocks that don't fit any more |
| */ |
| for (blk = fs->super->s_blocks_count; |
| blk < rfs->old_fs->super->s_blocks_count; blk++) { |
| if (ext2fs_test_block_bitmap(rfs->old_fs->block_map, blk)) |
| rfs->needed_blocks++; |
| ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk); |
| } |
| |
| old_blocks = rfs->old_fs->desc_blocks; |
| new_blocks = fs->desc_blocks; |
| |
| if (old_blocks == new_blocks) |
| return 0; |
| |
| max = fs->group_desc_count; |
| if (max > rfs->old_fs->group_desc_count) |
| max = rfs->old_fs->group_desc_count; |
| group_blk = rfs->old_fs->super->s_first_data_block; |
| /* |
| * If we're reducing the number of descriptor blocks, this |
| * makes life easy. :-) We just have to mark some extra |
| * blocks as free. |
| */ |
| if (old_blocks > new_blocks) { |
| for (i = 0; i < max; i++) { |
| if (!ext2fs_bg_has_super(fs, i)) { |
| group_blk += fs->super->s_blocks_per_group; |
| continue; |
| } |
| for (blk = group_blk+1+old_blocks; |
| blk < group_blk+1+new_blocks; blk++) { |
| ext2fs_unmark_block_bitmap(fs->block_map, |
| blk); |
| rfs->needed_blocks--; |
| } |
| group_blk += fs->super->s_blocks_per_group; |
| } |
| return 0; |
| } |
| /* |
| * If we're increasing the number of descriptor blocks, life |
| * gets interesting.... |
| */ |
| for (i = 0; i < max; i++) { |
| if (!ext2fs_bg_has_super(fs, i)) |
| goto next_group; |
| |
| for (blk = group_blk; |
| blk < group_blk + 1 + new_blocks; blk++) { |
| ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk); |
| ext2fs_mark_block_bitmap(fs->block_map, blk); |
| |
| /* |
| * Check to see if we overlap with the inode |
| * or block bitmap |
| */ |
| if (blk == fs->group_desc[i].bg_block_bitmap) { |
| fs->group_desc[i].bg_block_bitmap = 0; |
| rfs->needed_blocks++; |
| } |
| if (blk == fs->group_desc[i].bg_inode_bitmap) { |
| fs->group_desc[i].bg_inode_bitmap = 0; |
| rfs->needed_blocks++; |
| } |
| /* |
| * Check to see if we overlap with the inode |
| * table |
| */ |
| if (blk < fs->group_desc[i].bg_inode_table) |
| continue; |
| if (blk >= (fs->group_desc[i].bg_inode_table + |
| fs->inode_blocks_per_group)) |
| continue; |
| fs->group_desc[i].bg_inode_table = 0; |
| blk = fs->group_desc[i].bg_inode_table + |
| fs->inode_blocks_per_group - 1; |
| } |
| if (fs->group_desc[i].bg_inode_table && |
| fs->group_desc[i].bg_inode_bitmap && |
| fs->group_desc[i].bg_block_bitmap) |
| goto next_group; |
| |
| /* |
| * Allocate the missing bitmap and inode table |
| * structures, passing in rfs->reserve_blocks to |
| * prevent a conflict. |
| */ |
| if (fs->group_desc[i].bg_block_bitmap) |
| ext2fs_mark_block_bitmap(rfs->reserve_blocks, |
| fs->group_desc[i].bg_block_bitmap); |
| if (fs->group_desc[i].bg_inode_bitmap) |
| ext2fs_mark_block_bitmap(rfs->reserve_blocks, |
| fs->group_desc[i].bg_inode_bitmap); |
| if (fs->group_desc[i].bg_inode_table) |
| for (blk = fs->group_desc[i].bg_inode_table, j=0; |
| j < fs->inode_blocks_per_group ; j++, blk++) |
| ext2fs_mark_block_bitmap(rfs->reserve_blocks, |
| blk); |
| |
| retval = ext2fs_allocate_group_table(fs, i, |
| rfs->reserve_blocks); |
| if (retval) |
| return retval; |
| |
| /* |
| * Now make sure these blocks are reserved in the new |
| * block bitmap |
| */ |
| ext2fs_mark_block_bitmap(fs->block_map, |
| fs->group_desc[i].bg_block_bitmap); |
| ext2fs_mark_block_bitmap(fs->block_map, |
| fs->group_desc[i].bg_inode_bitmap); |
| |
| /* |
| * The inode table, if we need to relocate it, is |
| * handled specially. We have to reserve the blocks |
| * for both the old and the new inode table, since we |
| * can't have the inode table be destroyed during the |
| * block relocation phase. |
| */ |
| adj = fs->group_desc[i].bg_inode_table - |
| rfs->old_fs->group_desc[i].bg_inode_table; |
| if (!adj) |
| goto next_group; /* inode table not moved */ |
| |
| /* |
| * Figure out how many blocks we need to have free. |
| * This takes into account that we need to reserve |
| * both inode tables, which may be overallping. |
| */ |
| if (adj < 0) |
| adj = -adj; |
| if (adj > fs->inode_blocks_per_group) |
| adj = fs->inode_blocks_per_group; |
| rfs->needed_blocks += fs->inode_blocks_per_group + adj; |
| |
| /* |
| * Mark the new inode table as in use in the new block |
| * allocation bitmap. |
| */ |
| for (blk = fs->group_desc[i].bg_inode_table, j=0; |
| j < fs->inode_blocks_per_group ; j++, blk++) |
| ext2fs_mark_block_bitmap(fs->block_map, blk); |
| /* |
| * Make sure the old inode table is reserved in the |
| * block reservation bitmap. |
| */ |
| for (blk = rfs->old_fs->group_desc[i].bg_inode_table, j=0; |
| j < fs->inode_blocks_per_group ; j++, blk++) |
| ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk); |
| |
| next_group: |
| group_blk += rfs->new_fs->super->s_blocks_per_group; |
| } |
| return 0; |
| } |
| |
| |
| /* |
| * A very scary routine --- this one moves the inode table around!!! |
| * |
| * After this you have to use the rfs->new_fs file handle to read and |
| * write inodes. |
| */ |
| errcode_t move_itables(ext2_resize_t rfs) |
| { |
| int i, max; |
| ext2_filsys fs = rfs->new_fs; |
| char *buf; |
| blk_t old, new; |
| errcode_t retval, err; |
| |
| printf("Hide the women and children --- " |
| "commencing inode table moves!!\n"); |
| |
| max = fs->group_desc_count; |
| if (max > rfs->old_fs->group_desc_count) |
| max = rfs->old_fs->group_desc_count; |
| |
| buf = malloc(fs->blocksize * fs->inode_blocks_per_group); |
| if (!buf) |
| return ENOMEM; |
| |
| for (i=0; i < max; i++) { |
| old = rfs->old_fs->group_desc[i].bg_inode_table; |
| new = fs->group_desc[i].bg_inode_table; |
| |
| printf("Group %d block %ld->%ld\n", i, old, new); |
| |
| if (old == new) |
| continue; |
| |
| retval = io_channel_read_blk(fs->io, old, |
| fs->inode_blocks_per_group, buf); |
| if (retval) |
| goto backout; |
| retval = io_channel_write_blk(fs->io, new, |
| fs->inode_blocks_per_group, buf); |
| if (retval) { |
| io_channel_write_blk(fs->io, old, |
| fs->inode_blocks_per_group, buf); |
| goto backout; |
| } |
| } |
| ext2fs_flush(rfs->new_fs); |
| printf("Inode table move finished.\n"); |
| return 0; |
| |
| backout: |
| printf("Error: %s; now backing out!\n", error_message(retval)); |
| while (--i >= 0) { |
| printf("Group %d block %ld->%ld\n", i, new, old); |
| old = rfs->old_fs->group_desc[i].bg_inode_table; |
| new = fs->group_desc[i].bg_inode_table; |
| |
| err = io_channel_read_blk(fs->io, new, |
| fs->inode_blocks_per_group, buf); |
| if (err) |
| continue; |
| err = io_channel_write_blk(fs->io, old, |
| fs->inode_blocks_per_group, buf); |
| } |
| return retval; |
| } |
| |
| /* |
| * Finally, recalculate the summary information |
| */ |
| static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs) |
| { |
| blk_t blk; |
| ino_t ino; |
| int group = 0; |
| int count = 0; |
| int total_free = 0; |
| int group_free = 0; |
| |
| /* |
| * First calculate the block statistics |
| */ |
| for (blk = fs->super->s_first_data_block; |
| blk < fs->super->s_blocks_count; blk++) { |
| if (!ext2fs_fast_test_block_bitmap(fs->block_map, blk)) { |
| group_free++; |
| total_free++; |
| } |
| count++; |
| if ((count == fs->super->s_blocks_per_group) || |
| (blk == fs->super->s_blocks_count-1)) { |
| fs->group_desc[group++].bg_free_blocks_count = |
| group_free; |
| count = 0; |
| group_free = 0; |
| } |
| } |
| fs->super->s_free_blocks_count = total_free; |
| |
| /* |
| * Next, calculate the inode statistics |
| */ |
| group_free = 0; |
| total_free = 0; |
| count = 0; |
| group = 0; |
| for (ino = 1; ino <= fs->super->s_inodes_count; ino++) { |
| if (!ext2fs_fast_test_inode_bitmap(fs->inode_map, ino)) { |
| group_free++; |
| total_free++; |
| } |
| count++; |
| if ((count == fs->super->s_inodes_per_group) || |
| (ino == fs->super->s_inodes_count)) { |
| fs->group_desc[group++].bg_free_inodes_count = |
| group_free; |
| count = 0; |
| group_free = 0; |
| } |
| } |
| fs->super->s_free_inodes_count = total_free; |
| ext2fs_mark_super_dirty(fs); |
| return 0; |
| } |
| |
| |
| |
| /* |
| * This is the top-level routine which does the dirty deed.... |
| */ |
| errcode_t resize_fs(ext2_filsys fs, blk_t new_size) |
| { |
| ext2_resize_t rfs; |
| errcode_t retval; |
| |
| retval = ext2fs_read_bitmaps(fs); |
| if (retval) |
| return retval; |
| |
| /* |
| * Create the data structure |
| */ |
| rfs = malloc(sizeof(struct ext2_resize_struct)); |
| if (!rfs) |
| return ENOMEM; |
| memset(rfs, 0, sizeof(struct ext2_resize_struct)); |
| |
| rfs->old_fs = fs; |
| retval = ext2fs_dup_handle(fs, &rfs->new_fs); |
| if (retval) |
| goto errout; |
| |
| retval = adjust_superblock(rfs, new_size); |
| if (retval) |
| goto errout; |
| |
| retval = determine_relocations(rfs); |
| if (retval) |
| goto errout; |
| |
| printf("Number of free blocks: %d, Needed: %d\n", |
| fs->super->s_free_blocks_count, rfs->needed_blocks); |
| |
| if (rfs->needed_blocks > fs->super->s_free_blocks_count) { |
| retval = ENOSPC; |
| goto errout; |
| } |
| |
| printf("\nOld superblock:\n"); |
| list_super(rfs->old_fs->super); |
| printf("\n\nNew superblock:\n"); |
| list_super(rfs->new_fs->super); |
| printf("\n"); |
| |
| retval = ext2fs_move_blocks(rfs->old_fs, rfs->reserve_blocks, |
| rfs->new_fs->block_map, |
| EXT2_BMOVE_GET_DBLIST); |
| if (retval) |
| return retval; |
| |
| retval = ext2fs_inode_move(rfs); |
| if (retval) |
| return retval; |
| |
| retval = move_itables(rfs); |
| if (retval) |
| return retval; |
| |
| retval = ext2fs_calculate_summary_stats(rfs->new_fs); |
| if (retval) |
| return retval; |
| |
| retval = ext2fs_close(rfs->new_fs); |
| if (retval) |
| return retval; |
| |
| ext2fs_free(rfs->old_fs); |
| |
| return 0; |
| |
| errout: |
| if (rfs->new_fs) |
| ext2fs_free(rfs->new_fs); |
| free(rfs); |
| return retval; |
| } |