[thirdparty/e2fsprogs.git] / resize / resize2fs.c

/*
 * resize2fs.c --- ext2 main routine
 *
 * Copyright (C) 1997, 1998 by Theodore Ts'o and
 *      PowerQuest, Inc.
 *
 * Copyright (C) 1999, 2000 by Theodore Ts'o
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

/*
 * Resizing a filesystem consists of the following phases:
 *
 *      1.  Adjust superblock and write out new parts of the inode
 *              table
 *      2.  Determine blocks which need to be relocated, and copy the
 *              contents of blocks from their old locations to the new ones.
 *      3.  Scan the inode table, doing the following:
 *              a.  If blocks have been moved, update the block
 *                      pointers in the inodes and indirect blocks to
 *                      point at the new block locations.
 *              b.  If parts of the inode table need to be evacuated,
 *                      copy inodes from their old locations to their
 *                      new ones.
 *              c.  If (b) needs to be done, note which blocks contain
 *                      directory information, since we will need to
 *                      update the directory information.
 *      4.  Update the directory blocks with the new inode locations.
 *      5.  Move the inode tables, if necessary.
 */

#include "config.h"
#include "resize2fs.h"
#include <time.h>

#ifdef __linux__                        /* Kludge for debugging */
#define RESIZE2FS_DEBUG
#endif

static void fix_uninit_block_bitmaps(ext2_filsys fs);
static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size);
static errcode_t blocks_to_move(ext2_resize_t rfs);
static errcode_t block_mover(ext2_resize_t rfs);
static errcode_t inode_scan_and_fix(ext2_resize_t rfs);
static errcode_t inode_ref_fix(ext2_resize_t rfs);
static errcode_t move_itables(ext2_resize_t rfs);
static errcode_t fix_resize_inode(ext2_filsys fs);
static errcode_t resize2fs_calculate_summary_stats(ext2_filsys fs);
static errcode_t fix_sb_journal_backup(ext2_filsys fs);
static errcode_t mark_table_blocks(ext2_filsys fs,
                                   ext2fs_block_bitmap bmap);
static errcode_t clear_sparse_super2_last_group(ext2_resize_t rfs);
static errcode_t reserve_sparse_super2_last_group(ext2_resize_t rfs,
                                                 ext2fs_block_bitmap meta_bmap);
static errcode_t resize_group_descriptors(ext2_resize_t rfs, blk64_t new_size);
static errcode_t move_bg_metadata(ext2_resize_t rfs);
static errcode_t zero_high_bits_in_inodes(ext2_resize_t rfs);

/*
 * Some helper functions to check if a block is in a metadata area
 */
static inline int is_block_bm(ext2_filsys fs, unsigned int grp, blk64_t blk)
{
        return blk == ext2fs_block_bitmap_loc(fs, grp);
}

static inline int is_inode_bm(ext2_filsys fs, unsigned int grp, blk64_t blk)
{
        return blk == ext2fs_inode_bitmap_loc(fs, grp);
}

static int is_inode_tb(ext2_filsys fs, unsigned int grp, blk64_t blk)
{
        return blk >= ext2fs_inode_table_loc(fs, grp) &&
               blk < (ext2fs_inode_table_loc(fs, grp) +
                      fs->inode_blocks_per_group);
}

/* Some bigalloc helper macros which are more succinct... */
#define B2C(x)  EXT2FS_B2C(fs, (x))
#define C2B(x)  EXT2FS_C2B(fs, (x))
#define EQ_CLSTR(x, y) (B2C(x) == B2C(y))
#define LE_CLSTR(x, y) (B2C(x) <= B2C(y))
#define LT_CLSTR(x, y) (B2C(x) <  B2C(y))
#define GE_CLSTR(x, y) (B2C(x) >= B2C(y))
#define GT_CLSTR(x, y) (B2C(x) >  B2C(y))

static int lazy_itable_init;

/*
 * This is the top-level routine which does the dirty deed....
 */
errcode_t resize_fs(ext2_filsys fs, blk64_t *new_size, int flags,
            errcode_t (*progress)(ext2_resize_t rfs, int pass,
                                          unsigned long cur,
                                          unsigned long max_val))
{
        ext2_resize_t   rfs;
        errcode_t       retval;
        struct resource_track   rtrack, overall_track;

        /*
         * Create the data structure
         */
        retval = ext2fs_get_mem(sizeof(struct ext2_resize_struct), &rfs);
        if (retval)
                return retval;

        memset(rfs, 0, sizeof(struct ext2_resize_struct));
        fs->priv_data = rfs;
        rfs->old_fs = fs;
        rfs->flags = flags;
        rfs->itable_buf  = 0;
        rfs->progress = progress;

        init_resource_track(&overall_track, "overall resize2fs", fs->io);
        init_resource_track(&rtrack, "read_bitmaps", fs->io);
        retval = ext2fs_read_bitmaps(fs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        fs->super->s_state |= EXT2_ERROR_FS;
        ext2fs_mark_super_dirty(fs);
        ext2fs_flush(fs);

        init_resource_track(&rtrack, "fix_uninit_block_bitmaps 1", fs->io);
        fix_uninit_block_bitmaps(fs);
        print_resource_track(rfs, &rtrack, fs->io);
        retval = ext2fs_dup_handle(fs, &rfs->new_fs);
        if (retval)
                goto errout;

        init_resource_track(&rtrack, "resize_group_descriptors", fs->io);
        retval = resize_group_descriptors(rfs, *new_size);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "move_bg_metadata", fs->io);
        retval = move_bg_metadata(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "zero_high_bits_in_metadata", fs->io);
        retval = zero_high_bits_in_inodes(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "adjust_superblock", fs->io);
        retval = adjust_superblock(rfs, *new_size);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "fix_uninit_block_bitmaps 2", fs->io);
        fix_uninit_block_bitmaps(rfs->new_fs);
        print_resource_track(rfs, &rtrack, fs->io);
        /* Clear the block bitmap uninit flag for the last block group */
        ext2fs_bg_flags_clear(rfs->new_fs, rfs->new_fs->group_desc_count - 1,
                             EXT2_BG_BLOCK_UNINIT);

        *new_size = ext2fs_blocks_count(rfs->new_fs->super);

        init_resource_track(&rtrack, "blocks_to_move", fs->io);
        retval = blocks_to_move(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

#ifdef RESIZE2FS_DEBUG
        if (rfs->flags & RESIZE_DEBUG_BMOVE)
                printf("Number of free blocks: %llu/%llu, Needed: %llu\n",
                       (unsigned long long) ext2fs_free_blocks_count(rfs->old_fs->super),
                       (unsigned long long) ext2fs_free_blocks_count(rfs->new_fs->super),
                       (unsigned long long) rfs->needed_blocks);
#endif

        init_resource_track(&rtrack, "block_mover", fs->io);
        retval = block_mover(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "inode_scan_and_fix", fs->io);
        retval = inode_scan_and_fix(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "inode_ref_fix", fs->io);
        retval = inode_ref_fix(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "move_itables", fs->io);
        retval = move_itables(rfs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        retval = clear_sparse_super2_last_group(rfs);
        if (retval)
                goto errout;

        init_resource_track(&rtrack, "calculate_summary_stats", fs->io);
        retval = resize2fs_calculate_summary_stats(rfs->new_fs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "fix_resize_inode", fs->io);
        retval = fix_resize_inode(rfs->new_fs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        init_resource_track(&rtrack, "fix_sb_journal_backup", fs->io);
        retval = fix_sb_journal_backup(rfs->new_fs);
        if (retval)
                goto errout;
        print_resource_track(rfs, &rtrack, fs->io);

        retval = ext2fs_set_gdt_csum(rfs->new_fs);
        if (retval)
                goto errout;

        rfs->new_fs->super->s_state &= ~EXT2_ERROR_FS;
        rfs->new_fs->flags &= ~EXT2_FLAG_MASTER_SB_ONLY;

        print_resource_track(rfs, &overall_track, fs->io);
        retval = ext2fs_close_free(&rfs->new_fs);
        if (retval)
                goto errout;

        rfs->flags = flags;

        ext2fs_free(rfs->old_fs);
        rfs->old_fs = NULL;
        if (rfs->itable_buf)
                ext2fs_free_mem(&rfs->itable_buf);
        if (rfs->reserve_blocks)
                ext2fs_free_block_bitmap(rfs->reserve_blocks);
        if (rfs->move_blocks)
                ext2fs_free_block_bitmap(rfs->move_blocks);
        ext2fs_free_mem(&rfs);

        return 0;

errout:
        if (rfs->new_fs) {
                ext2fs_free(rfs->new_fs);
                rfs->new_fs = NULL;
        }
        if (rfs->itable_buf)
                ext2fs_free_mem(&rfs->itable_buf);
        ext2fs_free_mem(&rfs);
        return retval;
}

/* Keep the size of the group descriptor region constant */
static void adjust_reserved_gdt_blocks(ext2_filsys old_fs, ext2_filsys fs)
{
        if (ext2fs_has_feature_resize_inode(fs->super) &&
            (old_fs->desc_blocks != fs->desc_blocks)) {
                int new;

                new = ((int) fs->super->s_reserved_gdt_blocks) +
                        (old_fs->desc_blocks - fs->desc_blocks);
                if (new < 0)
                        new = 0;
                if (new > (int) fs->blocksize/4)
                        new = fs->blocksize/4;
                fs->super->s_reserved_gdt_blocks = new;
        }
}

/* Toggle 64bit mode */
static errcode_t resize_group_descriptors(ext2_resize_t rfs, blk64_t new_size)
{
        void *o, *n, *new_group_desc;
        dgrp_t i;
        int copy_size;
        errcode_t retval;

        if (!(rfs->flags & (RESIZE_DISABLE_64BIT | RESIZE_ENABLE_64BIT)))
                return 0;

        if (new_size != ext2fs_blocks_count(rfs->new_fs->super) ||
            ext2fs_blocks_count(rfs->new_fs->super) >= (1ULL << 32) ||
            (rfs->flags & RESIZE_DISABLE_64BIT &&
             rfs->flags & RESIZE_ENABLE_64BIT))
                return EXT2_ET_INVALID_ARGUMENT;

        if (rfs->flags & RESIZE_DISABLE_64BIT) {
                ext2fs_clear_feature_64bit(rfs->new_fs->super);
                rfs->new_fs->super->s_desc_size = EXT2_MIN_DESC_SIZE;
        } else if (rfs->flags & RESIZE_ENABLE_64BIT) {
                ext2fs_set_feature_64bit(rfs->new_fs->super);
                rfs->new_fs->super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT;
        }

        if (EXT2_DESC_SIZE(rfs->old_fs->super) ==
            EXT2_DESC_SIZE(rfs->new_fs->super))
                return 0;

        o = rfs->new_fs->group_desc;
        rfs->new_fs->desc_blocks = ext2fs_div_ceil(
                        rfs->old_fs->group_desc_count,
                        EXT2_DESC_PER_BLOCK(rfs->new_fs->super));
        retval = ext2fs_get_arrayzero(rfs->new_fs->desc_blocks,
                                      rfs->old_fs->blocksize, &new_group_desc);
        if (retval)
                return retval;

        n = new_group_desc;

        if (EXT2_DESC_SIZE(rfs->old_fs->super) <=
            EXT2_DESC_SIZE(rfs->new_fs->super))
                copy_size = EXT2_DESC_SIZE(rfs->old_fs->super);
        else
                copy_size = EXT2_DESC_SIZE(rfs->new_fs->super);
        for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
                memcpy(n, o, copy_size);
                n = (char *)n + EXT2_DESC_SIZE(rfs->new_fs->super);
                o = (char *)o + EXT2_DESC_SIZE(rfs->old_fs->super);
        }

        ext2fs_free_mem(&rfs->new_fs->group_desc);
        rfs->new_fs->group_desc = new_group_desc;

        for (i = 0; i < rfs->old_fs->group_desc_count; i++)
                ext2fs_group_desc_csum_set(rfs->new_fs, i);

        adjust_reserved_gdt_blocks(rfs->old_fs, rfs->new_fs);

        return 0;
}

/* Move bitmaps/inode tables out of the way. */
static errcode_t move_bg_metadata(ext2_resize_t rfs)
{
        dgrp_t i;
        blk64_t b, c, d, old_desc_blocks, new_desc_blocks, j;
        ext2fs_block_bitmap old_map, new_map;
        int old, new;
        errcode_t retval;
        int cluster_ratio;

        if (!(rfs->flags & (RESIZE_DISABLE_64BIT | RESIZE_ENABLE_64BIT)))
                return 0;

        retval = ext2fs_allocate_block_bitmap(rfs->old_fs, "oldfs", &old_map);
        if (retval)
                return retval;

        retval = ext2fs_allocate_block_bitmap(rfs->new_fs, "newfs", &new_map);
        if (retval)
                goto out;

        if (ext2fs_has_feature_meta_bg(rfs->old_fs->super)) {
                old_desc_blocks = rfs->old_fs->super->s_first_meta_bg;
                new_desc_blocks = rfs->new_fs->super->s_first_meta_bg;
        } else {
                old_desc_blocks = rfs->old_fs->desc_blocks +
                                rfs->old_fs->super->s_reserved_gdt_blocks;
                new_desc_blocks = rfs->new_fs->desc_blocks +
                                rfs->new_fs->super->s_reserved_gdt_blocks;
        }

        /* Construct bitmaps of super/descriptor blocks in old and new fs */
        for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
                retval = ext2fs_super_and_bgd_loc2(rfs->old_fs, i, &b, &c, &d,
                                                   NULL);
                if (retval)
                        goto out;
                if (b)
                        ext2fs_mark_block_bitmap2(old_map, b);
                for (j = 0; c != 0 && j < old_desc_blocks; j++)
                        ext2fs_mark_block_bitmap2(old_map, c + j);
                if (d)
                        ext2fs_mark_block_bitmap2(old_map, d);

                retval = ext2fs_super_and_bgd_loc2(rfs->new_fs, i, &b, &c, &d,
                                                   NULL);
                if (retval)
                        goto out;
                if (b)
                        ext2fs_mark_block_bitmap2(new_map, b);
                for (j = 0; c != 0 && j < new_desc_blocks; j++)
                        ext2fs_mark_block_bitmap2(new_map, c + j);
                if (d)
                        ext2fs_mark_block_bitmap2(new_map, d);
        }

        cluster_ratio = EXT2FS_CLUSTER_RATIO(rfs->new_fs);

        /* Find changes in block allocations for bg metadata */
        for (b = EXT2FS_B2C(rfs->old_fs,
                            rfs->old_fs->super->s_first_data_block);
             b < ext2fs_blocks_count(rfs->new_fs->super);
             b += cluster_ratio) {
                old = ext2fs_test_block_bitmap2(old_map, b);
                new = ext2fs_test_block_bitmap2(new_map, b);

                if (old && !new) {
                        /* mark old_map, unmark new_map */
                        if (cluster_ratio == 1)
                                ext2fs_unmark_block_bitmap2(
                                                rfs->new_fs->block_map, b);
                } else if (!old && new)
                        ; /* unmark old_map, mark new_map */
                else {
                        ext2fs_unmark_block_bitmap2(old_map, b);
                        ext2fs_unmark_block_bitmap2(new_map, b);
                }
        }

        /*
         * new_map now shows blocks that have been newly allocated.
         * old_map now shows blocks that have been newly freed.
         */

        /*
         * Move any conflicting bitmaps and inode tables.  Ensure that we
         * don't try to free clusters associated with bitmaps or tables.
         */
        for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
                b = ext2fs_block_bitmap_loc(rfs->new_fs, i);
                if (ext2fs_test_block_bitmap2(new_map, b))
                        ext2fs_block_bitmap_loc_set(rfs->new_fs, i, 0);
                else if (ext2fs_test_block_bitmap2(old_map, b))
                        ext2fs_unmark_block_bitmap2(old_map, b);

                b = ext2fs_inode_bitmap_loc(rfs->new_fs, i);
                if (ext2fs_test_block_bitmap2(new_map, b))
                        ext2fs_inode_bitmap_loc_set(rfs->new_fs, i, 0);
                else if (ext2fs_test_block_bitmap2(old_map, b))
                        ext2fs_unmark_block_bitmap2(old_map, b);

                c = ext2fs_inode_table_loc(rfs->new_fs, i);
                for (b = 0;
                     b < rfs->new_fs->inode_blocks_per_group;
                     b++) {
                        if (ext2fs_test_block_bitmap2(new_map, b + c))
                                ext2fs_inode_table_loc_set(rfs->new_fs, i, 0);
                        else if (ext2fs_test_block_bitmap2(old_map, b + c))
                                ext2fs_unmark_block_bitmap2(old_map, b + c);
                }
        }

        /* Free unused clusters */
        for (b = 0;
             cluster_ratio > 1 && b < ext2fs_blocks_count(rfs->new_fs->super);
             b += cluster_ratio)
                if (ext2fs_test_block_bitmap2(old_map, b))
                        ext2fs_unmark_block_bitmap2(rfs->new_fs->block_map, b);
out:
        if (old_map)
                ext2fs_free_block_bitmap(old_map);
        if (new_map)
                ext2fs_free_block_bitmap(new_map);
        return retval;
}

/* Zero out the high bits of extent fields */
static errcode_t zero_high_bits_in_extents(ext2_filsys fs, ext2_ino_t ino,
                                 struct ext2_inode *inode)
{
        ext2_extent_handle_t    handle;
        struct ext2fs_extent    extent;
        int                     op = EXT2_EXTENT_ROOT;
        errcode_t               errcode;

        if (!(inode->i_flags & EXT4_EXTENTS_FL))
                return 0;

        errcode = ext2fs_extent_open(fs, ino, &handle);
        if (errcode)
                return errcode;

        while (1) {
                errcode = ext2fs_extent_get(handle, op, &extent);
                if (errcode)
                        break;

                op = EXT2_EXTENT_NEXT_SIB;

                if (extent.e_pblk > (1ULL << 32)) {
                        extent.e_pblk &= (1ULL << 32) - 1;
                        errcode = ext2fs_extent_replace(handle, 0, &extent);
                        if (errcode)
                                break;
                }
        }

        /* Ok if we run off the end */
        if (errcode == EXT2_ET_EXTENT_NO_NEXT)
                errcode = 0;
        ext2fs_extent_free(handle);
        return errcode;
}

/* Zero out the high bits of inodes. */
static errcode_t zero_high_bits_in_inodes(ext2_resize_t rfs)
{
        ext2_filsys     fs = rfs->old_fs;
        int length = EXT2_INODE_SIZE(fs->super);
        struct ext2_inode *inode = NULL;
        ext2_inode_scan scan = NULL;
        errcode_t       retval;
        ext2_ino_t      ino;

        if (!(rfs->flags & (RESIZE_DISABLE_64BIT | RESIZE_ENABLE_64BIT)))
                return 0;

        if (fs->super->s_creator_os == EXT2_OS_HURD)
                return 0;

        retval = ext2fs_open_inode_scan(fs, 0, &scan);
        if (retval)
                return retval;

        retval = ext2fs_get_mem(length, &inode);
        if (retval)
                goto out;

        do {
                retval = ext2fs_get_next_inode_full(scan, &ino, inode, length);
                if (retval)
                        goto out;
                if (!ino)
                        break;
                if (!ext2fs_test_inode_bitmap2(fs->inode_map, ino))
                        continue;

                /*
                 * Here's how we deal with high block number fields:
                 *
                 *  - i_size_high has been been written out with i_size_lo
                 *    since the ext2 days, so no conversion is needed.
                 *
                 *  - i_blocks_hi is guarded by both the huge_file feature and
                 *    inode flags and has always been written out with
                 *    i_blocks_lo if the feature is set.  The field is only
                 *    ever read if both feature and inode flag are set, so
                 *    we don't need to zero it now.
                 *
                 *  - i_file_acl_high can be uninitialized, so zero it if
                 *    it isn't already.
                 */
                if (inode->osd2.linux2.l_i_file_acl_high) {
                        inode->osd2.linux2.l_i_file_acl_high = 0;
                        retval = ext2fs_write_inode_full(fs, ino, inode,
                                                         length);
                        if (retval)
                                goto out;
                }

                retval = zero_high_bits_in_extents(fs, ino, inode);
                if (retval)
                        goto out;
        } while (ino);

out:
        if (inode)
                ext2fs_free_mem(&inode);
        if (scan)
                ext2fs_close_inode_scan(scan);
        return retval;
}

/*
 * Clean up the bitmaps for uninitialized bitmaps
 */
static void fix_uninit_block_bitmaps(ext2_filsys fs)
{
        blk64_t         blk, lblk;
        dgrp_t          g;
        unsigned int    i;

        if (!ext2fs_has_group_desc_csum(fs))
                return;

        for (g=0; g < fs->group_desc_count; g++) {
                if (!(ext2fs_bg_flags_test(fs, g, EXT2_BG_BLOCK_UNINIT)))
                        continue;

                blk = ext2fs_group_first_block2(fs, g);
                lblk = ext2fs_group_last_block2(fs, g);
                ext2fs_unmark_block_bitmap_range2(fs->block_map, blk,
                                                  lblk - blk + 1);

                ext2fs_reserve_super_and_bgd(fs, g, fs->block_map);
                ext2fs_mark_block_bitmap2(fs->block_map,
                                          ext2fs_block_bitmap_loc(fs, g));
                ext2fs_mark_block_bitmap2(fs->block_map,
                                          ext2fs_inode_bitmap_loc(fs, g));
                for (i = 0, blk = ext2fs_inode_table_loc(fs, g);
                     i < fs->inode_blocks_per_group;
                     i++, blk++)
                        ext2fs_mark_block_bitmap2(fs->block_map, blk);
        }
}

/* --------------------------------------------------------------------
 *
 * Resize processing, phase 1.
 *
 * In this phase we adjust the in-memory superblock information, and
 * initialize any new parts of the inode table.  The new parts of the
 * inode table are created in virgin disk space, so we can abort here
 * without any side effects.
 * --------------------------------------------------------------------
 */

/*
 * If the group descriptor's bitmap and inode table blocks are valid,
 * release them in the new filesystem data structure, and mark them as
 * reserved so the old inode table blocks don't get overwritten.
 */
static errcode_t free_gdp_blocks(ext2_filsys fs,
                                 ext2fs_block_bitmap reserve_blocks,
                                 ext2_filsys old_fs,
                                 dgrp_t group)
{
        blk64_t         blk;
        unsigned int    j;
        dgrp_t          i;
        ext2fs_block_bitmap bg_map = NULL;
        errcode_t       retval = 0;
        dgrp_t          count = old_fs->group_desc_count - fs->group_desc_count;

        /* If bigalloc, don't free metadata living in the same cluster */
        if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
                retval = ext2fs_allocate_block_bitmap(fs, "bgdata", &bg_map);
                if (retval)
                        goto out;

                retval = mark_table_blocks(fs, bg_map);
                if (retval)
                        goto out;
        }

        for (i = group; i < group + count; i++) {
                blk = ext2fs_block_bitmap_loc(old_fs, i);
                if (blk &&
                    (blk < ext2fs_blocks_count(fs->super)) &&
                    !(bg_map && ext2fs_test_block_bitmap2(bg_map, blk))) {
                        ext2fs_block_alloc_stats2(fs, blk, -1);
                        ext2fs_mark_block_bitmap2(reserve_blocks, blk);
                }

                blk = ext2fs_inode_bitmap_loc(old_fs, i);
                if (blk &&
                    (blk < ext2fs_blocks_count(fs->super)) &&
                    !(bg_map && ext2fs_test_block_bitmap2(bg_map, blk))) {
                        ext2fs_block_alloc_stats2(fs, blk, -1);
                        ext2fs_mark_block_bitmap2(reserve_blocks, blk);
                }

                blk = ext2fs_inode_table_loc(old_fs, i);
                for (j = 0;
                     j < fs->inode_blocks_per_group; j++, blk++) {
                        if (blk >= ext2fs_blocks_count(fs->super) ||
                            (bg_map && ext2fs_test_block_bitmap2(bg_map, blk)))
                                continue;
                        ext2fs_block_alloc_stats2(fs, blk, -1);
                        ext2fs_mark_block_bitmap2(reserve_blocks, blk);
                }
        }

out:
        if (bg_map)
                ext2fs_free_block_bitmap(bg_map);
        return retval;
}

/*
 * This routine is shared by the online and offline resize routines.
 * All of the information which is adjusted in memory is done here.
 */
errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
                         ext2fs_block_bitmap reserve_blocks, blk64_t new_size)
{
        errcode_t       retval;
        blk64_t         overhead = 0;
        blk64_t         rem;
        blk64_t         blk, group_block;
        blk64_t         real_end;
        blk64_t         old_numblocks, numblocks, adjblocks;
        unsigned long   i, j, old_desc_blocks;
        unsigned int    meta_bg, meta_bg_size;
        int             has_super, csum_flag, has_bg;
        unsigned long long new_inodes;  /* u64 to check for overflow */
        double          percent;

        ext2fs_blocks_count_set(fs->super, new_size);
        fs->super->s_overhead_clusters = 0;

retry:
        fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
                                       fs->super->s_first_data_block,
                                       EXT2_BLOCKS_PER_GROUP(fs->super));
        if (fs->group_desc_count == 0)
                return EXT2_ET_TOOSMALL;
        fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
                                          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.
         */
        overhead = (int) (2 + fs->inode_blocks_per_group);

        has_bg = 0;
        if (ext2fs_has_feature_sparse_super2(fs->super)) {
                /*
                 * We have to do this manually since
                 * super->s_backup_bgs hasn't been set up yet.
                 */
                if (fs->group_desc_count == 2)
                        has_bg = fs->super->s_backup_bgs[0] != 0;
                else
                        has_bg = fs->super->s_backup_bgs[1] != 0;
        } else
                has_bg = ext2fs_bg_has_super(fs, fs->group_desc_count - 1);
        if (has_bg)
                overhead += 1 + fs->desc_blocks +
                        fs->super->s_reserved_gdt_blocks;

        /*
         * See if the last group is big enough to support the
         * necessary data structures.  If not, we need to get rid of
         * it.
         */
        rem = (ext2fs_blocks_count(fs->super) - 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 ((fs->group_desc_count > 1) && rem && (rem < overhead+50)) {
                ext2fs_blocks_count_set(fs->super,
                                        ext2fs_blocks_count(fs->super) - rem);
                goto retry;
        }
        /*
         * Adjust the number of inodes
         */
        new_inodes =(unsigned long long) fs->super->s_inodes_per_group * fs->group_desc_count;
        if (new_inodes > ~0U) {
                new_inodes = (unsigned long long) fs->super->s_inodes_per_group * (fs->group_desc_count - 1);
                if (new_inodes <= ~0U) {
                        unsigned long long new_blocks =
                ((unsigned long long) fs->super->s_blocks_per_group *
                 (fs->group_desc_count - 1)) + fs->super->s_first_data_block;

                        ext2fs_blocks_count_set(fs->super, new_blocks);
                        goto retry;
                }
                fprintf(stderr, _("inodes (%llu) must be less than %u\n"),
                        (unsigned long long) new_inodes, ~0U);
                return EXT2_ET_TOO_MANY_INODES;
        }
        fs->super->s_inodes_count = fs->super->s_inodes_per_group *
                fs->group_desc_count;

        /*
         * Adjust the number of free blocks
         */
        blk = ext2fs_blocks_count(old_fs->super);
        if (blk > ext2fs_blocks_count(fs->super))
                ext2fs_free_blocks_count_set(fs->super, 
                        ext2fs_free_blocks_count(fs->super) -
                        (blk - ext2fs_blocks_count(fs->super)));
        else
                ext2fs_free_blocks_count_set(fs->super, 
                        ext2fs_free_blocks_count(fs->super) +
                        (ext2fs_blocks_count(fs->super) - blk));

        /*
         * Adjust the number of reserved blocks
         */
        percent = (ext2fs_r_blocks_count(old_fs->super) * 100.0) /
                ext2fs_blocks_count(old_fs->super);
        ext2fs_r_blocks_count_set(fs->super,
                                  (percent * ext2fs_blocks_count(fs->super) /
                                   100.0));

        /*
         * Adjust the bitmaps for size
         */
        retval = ext2fs_resize_inode_bitmap2(fs->super->s_inodes_count,
                                            fs->super->s_inodes_count,
                                            fs->inode_map);
        if (retval) goto errout;

        real_end = EXT2_GROUPS_TO_BLOCKS(fs->super, fs->group_desc_count) - 1 +
                fs->super->s_first_data_block;
        retval = ext2fs_resize_block_bitmap2(new_size - 1,
                                             real_end, fs->block_map);
        if (retval) goto errout;

        /*
         * If we are growing the file system, also grow the size of
         * the reserve_blocks bitmap
         */
        if (reserve_blocks && new_size > ext2fs_blocks_count(old_fs->super)) {
                retval = ext2fs_resize_block_bitmap2(new_size - 1,
                                                     real_end, reserve_blocks);
                if (retval) goto errout;
        }

        /*
         * Reallocate the group descriptors as necessary.
         */
        if (EXT2_DESC_SIZE(old_fs->super) == EXT2_DESC_SIZE(fs->super) &&
            old_fs->desc_blocks != fs->desc_blocks) {
                retval = ext2fs_resize_mem(old_fs->desc_blocks *
                                           fs->blocksize,
                                           fs->desc_blocks * fs->blocksize,
                                           &fs->group_desc);
                if (retval)
                        goto errout;
                if (fs->desc_blocks > old_fs->desc_blocks)
                        memset((char *) fs->group_desc +
                               (old_fs->desc_blocks * fs->blocksize), 0,
                               (fs->desc_blocks - old_fs->desc_blocks) *
                               fs->blocksize);
        }

        /*
         * If the resize_inode feature is set, and we are changing the
         * number of descriptor blocks, then adjust
         * s_reserved_gdt_blocks if possible to avoid needing to move
         * the inode table either now or in the future.
         *
         * Note: If we're converting to 64bit mode, we did this earlier.
         */
        if (EXT2_DESC_SIZE(old_fs->super) == EXT2_DESC_SIZE(fs->super))
                adjust_reserved_gdt_blocks(old_fs, fs);

        if (ext2fs_has_feature_meta_bg(fs->super) &&
            (fs->super->s_first_meta_bg > fs->desc_blocks)) {
                ext2fs_clear_feature_meta_bg(fs->super);
                fs->super->s_first_meta_bg = 0;
        }

        /*
         * Update the location of the backup superblocks if the
         * sparse_super2 feature is enabled.
         */
        if (ext2fs_has_feature_sparse_super2(fs->super)) {
                dgrp_t last_bg = fs->group_desc_count - 1;
                dgrp_t old_last_bg = old_fs->group_desc_count - 1;

                if (last_bg > old_last_bg) {
                        if (old_fs->group_desc_count == 1)
                                fs->super->s_backup_bgs[0] = 1;
                        if ((old_fs->group_desc_count < 3 &&
                             fs->group_desc_count > 2) ||
                            fs->super->s_backup_bgs[1])
                                fs->super->s_backup_bgs[1] = last_bg;
                } else if (last_bg < old_last_bg) {
                        if (fs->super->s_backup_bgs[0] > last_bg)
                                fs->super->s_backup_bgs[0] = 0;
                        if (fs->super->s_backup_bgs[1] > last_bg)
                                fs->super->s_backup_bgs[1] = 0;
                        if (last_bg > 1 &&
                            old_fs->super->s_backup_bgs[1] == old_last_bg)
                                fs->super->s_backup_bgs[1] = last_bg;
                }
        }

        /*
         * If we are shrinking the number of block groups, we're done
         * and can exit now.
         */
        if (old_fs->group_desc_count > fs->group_desc_count) {
                /*
                 * Check the block groups that we are chopping off
                 * and free any blocks associated with their metadata
                 */
                retval = free_gdp_blocks(fs, reserve_blocks, old_fs,
                                         fs->group_desc_count);
                goto errout;
        }

        /*
         * Fix the count of the last (old) block group
         */
        old_numblocks = (ext2fs_blocks_count(old_fs->super) -
                         old_fs->super->s_first_data_block) %
                                 old_fs->super->s_blocks_per_group;
        if (!old_numblocks)
                old_numblocks = old_fs->super->s_blocks_per_group;
        if (old_fs->group_desc_count == fs->group_desc_count) {
                numblocks = (ext2fs_blocks_count(fs->super) -
                             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;
        i = old_fs->group_desc_count - 1;
        ext2fs_bg_free_blocks_count_set(fs, i, ext2fs_bg_free_blocks_count(fs, i) + (numblocks - old_numblocks));
        ext2fs_group_desc_csum_set(fs, i);

        /*
         * If the number of block groups is staying the same, we're
         * done and can exit now.  (If the number block groups is
         * shrinking, we had exited earlier.)
         */
        if (old_fs->group_desc_count >= fs->group_desc_count) {
                retval = 0;
                goto errout;
        }

        /*
         * Initialize the new block group descriptors
         */
        group_block = ext2fs_group_first_block2(fs,
                                                old_fs->group_desc_count);
        csum_flag = ext2fs_has_group_desc_csum(fs);
        if (getenv("RESIZE2FS_FORCE_LAZY_ITABLE_INIT") ||
            (!getenv("RESIZE2FS_FORCE_ITABLE_INIT") &&
             access("/sys/fs/ext4/features/lazy_itable_init", F_OK) == 0))
                lazy_itable_init = 1;
        if (ext2fs_has_feature_meta_bg(fs->super))
                old_desc_blocks = fs->super->s_first_meta_bg;
        else
                old_desc_blocks = fs->desc_blocks +
                        fs->super->s_reserved_gdt_blocks;

        /*
         * If we changed the number of block_group descriptor blocks,
         * we need to make sure they are all marked as reserved in the
         * filesystem's block allocation map.
         */
        for (i = 0; i < old_fs->group_desc_count; i++)
                ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);

        for (i = old_fs->group_desc_count;
             i < fs->group_desc_count; i++) {
                memset(ext2fs_group_desc(fs, fs->group_desc, i), 0,
                       sizeof(struct ext2_group_desc));
                adjblocks = 0;

                ext2fs_bg_flags_zap(fs, i);
                if (csum_flag) {
                        ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
                        if (!lazy_itable_init)
                                ext2fs_bg_flags_set(fs, i,
                                                    EXT2_BG_INODE_ZEROED);
                        ext2fs_bg_itable_unused_set(fs, i,
                                        fs->super->s_inodes_per_group);
                }

                numblocks = ext2fs_group_blocks_count(fs, i);
                if ((i < fs->group_desc_count - 1) && csum_flag)
                        ext2fs_bg_flags_set(fs, i, EXT2_BG_BLOCK_UNINIT);

                has_super = ext2fs_bg_has_super(fs, i);
                if (has_super) {
                        ext2fs_block_alloc_stats2(fs, group_block, +1);
                        adjblocks++;
                }
                meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
                meta_bg = i / meta_bg_size;
                if (!ext2fs_has_feature_meta_bg(fs->super) ||
                    (meta_bg < fs->super->s_first_meta_bg)) {
                        if (has_super) {
                                for (j=0; j < old_desc_blocks; j++)
                                        ext2fs_block_alloc_stats2(fs,
                                                 group_block + 1 + j, +1);
                                adjblocks += old_desc_blocks;
                        }
                } else {
                        if (has_super)
                                has_super = 1;
                        if (((i % meta_bg_size) == 0) ||
                            ((i % meta_bg_size) == 1) ||
                            ((i % meta_bg_size) == (meta_bg_size-1)))
                                ext2fs_block_alloc_stats2(fs,
                                                 group_block + has_super, +1);
                }

                adjblocks += 2 + fs->inode_blocks_per_group;

                numblocks -= adjblocks;
                ext2fs_free_blocks_count_set(fs->super,
                             ext2fs_free_blocks_count(fs->super) - adjblocks);
                fs->super->s_free_inodes_count +=
                        fs->super->s_inodes_per_group;
                ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
                ext2fs_bg_free_inodes_count_set(fs, i,
                                                fs->super->s_inodes_per_group);
                ext2fs_bg_used_dirs_count_set(fs, i, 0);
                ext2fs_group_desc_csum_set(fs, i);

                retval = ext2fs_allocate_group_table(fs, i, 0);
                if (retval) goto errout;

                group_block += fs->super->s_blocks_per_group;
        }
        retval = 0;

        /*
         * Mark all of the metadata blocks as reserved so they won't
         * get allocated by the call to ext2fs_allocate_group_table()
         * in blocks_to_move(), where we allocate new blocks to
         * replace those allocation bitmap and inode table blocks
         * which have to get relocated to make space for an increased
         * number of the block group descriptors.
         */
        if (reserve_blocks)
                mark_table_blocks(fs, reserve_blocks);

errout:
        return (retval);
}

/*
 * This routine adjusts the superblock and other data structures, both
 * in disk as well as in memory...
 */
static errcode_t adjust_superblock(ext2_resize_t rfs, blk64_t new_size)
{
        ext2_filsys     fs = rfs->new_fs;
        int             adj = 0;
        errcode_t       retval;
        blk64_t         group_block;
        unsigned long   i;
        unsigned long   max_group;

        ext2fs_mark_super_dirty(fs);
        ext2fs_mark_bb_dirty(fs);
        ext2fs_mark_ib_dirty(fs);

        retval = ext2fs_allocate_block_bitmap(fs, _("reserved blocks"),
                                              &rfs->reserve_blocks);
        if (retval)
                return retval;

        retval = adjust_fs_info(fs, rfs->old_fs, rfs->reserve_blocks, new_size);
        if (retval)
                goto errout;

        /*
         * Check to make sure there are enough inodes
         */
        if ((rfs->old_fs->super->s_inodes_count -
             rfs->old_fs->super->s_free_inodes_count) >
            rfs->new_fs->super->s_inodes_count) {
                retval = ENOSPC;
                goto errout;
        }

        /*
         * If we are shrinking the number block groups, we're done and
         * can exit now.
         */
        if (rfs->old_fs->group_desc_count > fs->group_desc_count) {
                retval = 0;
                goto errout;
        }

        /*
         * If the number of block groups is staying the same, we're
         * done and can exit now.  (If the number block groups is
         * shrinking, we had exited earlier.)
         */
        if (rfs->old_fs->group_desc_count >= fs->group_desc_count) {
                retval = 0;
                goto errout;
        }

        /*
         * If we are using uninit_bg (aka GDT_CSUM) and the kernel
         * supports lazy inode initialization, we can skip
         * initializing the inode table.
         */
        if (lazy_itable_init && ext2fs_has_group_desc_csum(fs)) {
                retval = 0;
                goto errout;
        }

        /*
         * Initialize the inode table
         */
        retval = ext2fs_get_array(fs->blocksize, fs->inode_blocks_per_group,
                                &rfs->itable_buf);
        if (retval)
                goto errout;

        memset(rfs->itable_buf, 0, fs->blocksize * fs->inode_blocks_per_group);
        group_block = ext2fs_group_first_block2(fs,
                                                rfs->old_fs->group_desc_count);
        adj = rfs->old_fs->group_desc_count;
        max_group = fs->group_desc_count - adj;
        if (rfs->progress) {
                retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
                                       0, max_group);
                if (retval)
                        goto errout;
        }
        for (i = rfs->old_fs->group_desc_count;
             i < fs->group_desc_count; i++) {
                /*
                 * Write out the new inode table
                 */
                retval = ext2fs_zero_blocks2(fs, ext2fs_inode_table_loc(fs, i),
                                             fs->inode_blocks_per_group, NULL,
                                             NULL);
                if (retval)
                        goto errout;

                io_channel_flush(fs->io);
                if (rfs->progress) {
                        retval = rfs->progress(rfs, E2_RSZ_EXTEND_ITABLE_PASS,
                                               i - adj + 1, max_group);
                        if (retval)
                                goto errout;
                }
                group_block += fs->super->s_blocks_per_group;
        }
        io_channel_flush(fs->io);
        retval = 0;

errout:
        return retval;
}

/* --------------------------------------------------------------------
 *
 * Resize processing, phase 2.
 *
 * In this phase we adjust determine which blocks need to be moved, in
 * blocks_to_move().  We then copy the blocks to their ultimate new
 * destinations using block_mover().  Since we are copying blocks to
 * their new locations, again during this pass we can abort without
 * any problems.
 * --------------------------------------------------------------------
 */

/*
 * This helper function creates a block bitmap with all of the
 * filesystem meta-data blocks.
 */
static errcode_t mark_table_blocks(ext2_filsys fs,
                                   ext2fs_block_bitmap bmap)
{
        dgrp_t                  i;
        blk64_t                 blk;

        for (i = 0; i < fs->group_desc_count; i++) {
                ext2fs_reserve_super_and_bgd(fs, i, bmap);

                /*
                 * Mark the blocks used for the inode table
                 */
                blk = ext2fs_inode_table_loc(fs, i);
                if (blk)
                        ext2fs_mark_block_bitmap_range2(bmap, blk,
                                                fs->inode_blocks_per_group);

                /*
                 * Mark block used for the block bitmap
                 */
                blk = ext2fs_block_bitmap_loc(fs, i);
                if (blk)
                        ext2fs_mark_block_bitmap2(bmap, blk);

                /*
                 * Mark block used for the inode bitmap
                 */
                blk = ext2fs_inode_bitmap_loc(fs, i);
                if (blk)
                        ext2fs_mark_block_bitmap2(bmap, blk);
        }
        /* Reserve the MMP block */
        if (ext2fs_has_feature_mmp(fs->super) &&
            fs->super->s_mmp_block > fs->super->s_first_data_block &&
            fs->super->s_mmp_block < ext2fs_blocks_count(fs->super))
                ext2fs_mark_block_bitmap2(bmap, fs->super->s_mmp_block);
        return 0;
}

/*
 * This function checks to see if a particular block (either a
 * superblock or a block group descriptor) overlaps with an inode or
 * block bitmap block, or with the inode table.
 */
static void mark_fs_metablock(ext2_resize_t rfs,
                              ext2fs_block_bitmap meta_bmap,
                              int group, blk64_t blk)
{
        ext2_filsys fs = rfs->new_fs;

        ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
        ext2fs_block_alloc_stats2(fs, blk, +1);

        /*
         * Check to see if we overlap with the inode or block bitmap,
         * or the inode tables.  If not, and the block is in use, then
         * mark it as a block to be moved.
         */
        if (is_block_bm(fs, group, blk)) {
                ext2fs_block_bitmap_loc_set(fs, group, 0);
                rfs->needed_blocks++;
                return;
        }
        if (is_inode_bm(fs, group, blk)) {
                ext2fs_inode_bitmap_loc_set(fs, group, 0);
                rfs->needed_blocks++;
                return;
        }
        if (is_inode_tb(fs, group, blk)) {
                ext2fs_inode_table_loc_set(fs, group, 0);
                rfs->needed_blocks++;
                return;
        }
        if (ext2fs_has_feature_flex_bg(fs->super)) {
                dgrp_t i;

                for (i = 0; i < rfs->old_fs->group_desc_count; i++) {
                        if (is_block_bm(fs, i, blk)) {
                                ext2fs_block_bitmap_loc_set(fs, i, 0);
                                rfs->needed_blocks++;
                                return;
                        }
                        if (is_inode_bm(fs, i, blk)) {
                                ext2fs_inode_bitmap_loc_set(fs, i, 0);
                                rfs->needed_blocks++;
                                return;
                        }
                        if (is_inode_tb(fs, i, blk)) {
                                ext2fs_inode_table_loc_set(fs, i, 0);
                                rfs->needed_blocks++;
                                return;
                        }
                }
        }

        if (ext2fs_has_group_desc_csum(fs) &&
            (ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT))) {
                /*
                 * If the block bitmap is uninitialized, which means
                 * nothing other than standard metadata in use.
                 */
                return;
        } else if (blk < ext2fs_blocks_count(rfs->old_fs->super) &&
                   ext2fs_test_block_bitmap2(rfs->old_fs->block_map, blk) &&
                   !ext2fs_test_block_bitmap2(meta_bmap, blk)) {
                ext2fs_mark_block_bitmap2(rfs->move_blocks, blk);
                rfs->needed_blocks++;
        }
}


/*
 * 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 blocks_to_move(ext2_resize_t rfs)
{
        unsigned int    j;
        int             has_super;
        dgrp_t          i, max_groups, g;
        blk64_t         blk, group_blk;
        blk64_t         old_blocks, new_blocks, group_end, cluster_freed;
        blk64_t         new_size;
        unsigned int    meta_bg, meta_bg_size;
        errcode_t       retval;
        ext2_filsys     fs, old_fs;
        ext2fs_block_bitmap     meta_bmap, new_meta_bmap = NULL;
        int             flex_bg;

        fs = rfs->new_fs;
        old_fs = rfs->old_fs;
        if (ext2fs_blocks_count(old_fs->super) > ext2fs_blocks_count(fs->super))
                fs = rfs->old_fs;

        retval = ext2fs_allocate_block_bitmap(fs, _("blocks to be moved"),
                                              &rfs->move_blocks);
        if (retval)
                return retval;

        retval = ext2fs_allocate_block_bitmap(fs, _("meta-data blocks"),
                                              &meta_bmap);
        if (retval)
                return retval;

        retval = mark_table_blocks(old_fs, meta_bmap);
        if (retval)
                return retval;

        fs = rfs->new_fs;

        /*
         * If we're shrinking the filesystem, we need to move any
         * group's metadata blocks (either allocation bitmaps or the
         * inode table) which are beyond the end of the new
         * filesystem.
         */
        new_size = ext2fs_blocks_count(fs->super);
        if (new_size < ext2fs_blocks_count(old_fs->super)) {
                for (g = 0; g < fs->group_desc_count; g++) {
                        int realloc = 0;
                        /*
                         * ext2fs_allocate_group_table will re-allocate any
                         * metadata blocks whose location is set to zero.
                         */
                        if (ext2fs_block_bitmap_loc(fs, g) >= new_size) {
                                ext2fs_block_bitmap_loc_set(fs, g, 0);
                                realloc = 1;
                        }
                        if (ext2fs_inode_bitmap_loc(fs, g) >= new_size) {
                                ext2fs_inode_bitmap_loc_set(fs, g, 0);
                                realloc = 1;
                        }
                        if ((ext2fs_inode_table_loc(fs, g) +
                             fs->inode_blocks_per_group) > new_size) {
                                ext2fs_inode_table_loc_set(fs, g, 0);
                                realloc = 1;
                        }

                        if (realloc) {
                                retval = ext2fs_allocate_group_table(fs, g, 0);
                                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 = ext2fs_blocks_count(fs->super);
             blk < ext2fs_blocks_count(old_fs->super); blk++) {
                g = ext2fs_group_of_blk2(fs, blk);
                if (ext2fs_has_group_desc_csum(fs) &&
                    ext2fs_bg_flags_test(old_fs, g, EXT2_BG_BLOCK_UNINIT)) {
                        /*
                         * The block bitmap is uninitialized, so skip
                         * to the next block group.
                         */
                        blk = ext2fs_group_first_block2(fs, g+1) - 1;
                        continue;
                }
                if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
                    !ext2fs_test_block_bitmap2(meta_bmap, blk)) {
                        ext2fs_mark_block_bitmap2(rfs->move_blocks, blk);
                        rfs->needed_blocks++;
                }
                ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
        }

        if (ext2fs_has_feature_meta_bg(old_fs->super))
                old_blocks = old_fs->super->s_first_meta_bg;
        else
                old_blocks = old_fs->desc_blocks +
                        old_fs->super->s_reserved_gdt_blocks;
        if (ext2fs_has_feature_meta_bg(fs->super))
                new_blocks = fs->super->s_first_meta_bg;
        else
                new_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;

        retval = reserve_sparse_super2_last_group(rfs, meta_bmap);
        if (retval)
                goto errout;

        if (EXT2_DESC_SIZE(rfs->old_fs->super) ==
            EXT2_DESC_SIZE(rfs->new_fs->super) &&
            old_blocks == new_blocks) {
                retval = 0;
                goto errout;
        }

        max_groups = fs->group_desc_count;
        if (max_groups > old_fs->group_desc_count)
                max_groups = old_fs->group_desc_count;
        group_blk = 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) {
                if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
                        retval = ext2fs_allocate_block_bitmap(fs,
                                                        _("new meta blocks"),
                                                        &new_meta_bmap);
                        if (retval)
                                goto errout;

                        retval = mark_table_blocks(fs, new_meta_bmap);
                        if (retval)
                                goto errout;
                }

                for (i = 0; i < max_groups; i++) {
                        if (!ext2fs_bg_has_super(old_fs, i)) {
                                group_blk += fs->super->s_blocks_per_group;
                                continue;
                        }
                        group_end = group_blk + 1 + old_blocks;
                        for (blk = group_blk + 1 + new_blocks;
                             blk < group_end;) {
                                if (new_meta_bmap == NULL ||
                                    !ext2fs_test_block_bitmap2(new_meta_bmap,
                                                               blk)) {
                                        cluster_freed =
                                                EXT2FS_CLUSTER_RATIO(fs) -
                                                (blk &
                                                 EXT2FS_CLUSTER_MASK(fs));
                                        if (cluster_freed > group_end - blk)
                                                cluster_freed = group_end - blk;
                                        ext2fs_block_alloc_stats2(fs, blk, -1);
                                        blk += EXT2FS_CLUSTER_RATIO(fs);
                                        rfs->needed_blocks -= cluster_freed;
                                        continue;
                                }
                                rfs->needed_blocks--;
                                blk++;
                        }
                        group_blk += fs->super->s_blocks_per_group;
                }
                retval = 0;
                goto errout;
        }
        /*
         * If we're increasing the number of descriptor blocks, life
         * gets interesting....
         */
        meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
        flex_bg = ext2fs_has_feature_flex_bg(fs->super);
        /* first reserve all of the existing fs meta blocks */
        for (i = 0; i < max_groups; i++) {
                has_super = ext2fs_bg_has_super(fs, i);
                if (has_super)
                        mark_fs_metablock(rfs, meta_bmap, i, group_blk);

                meta_bg = i / meta_bg_size;
                if (!ext2fs_has_feature_meta_bg(fs->super) ||
                    (meta_bg < fs->super->s_first_meta_bg)) {
                        if (has_super) {
                                for (blk = group_blk+1;
                                     blk < group_blk + 1 + new_blocks; blk++)
                                        mark_fs_metablock(rfs, meta_bmap,
                                                          i, blk);
                        }
                } else {
                        if (has_super)
                                has_super = 1;
                        if (((i % meta_bg_size) == 0) ||
                            ((i % meta_bg_size) == 1) ||
                            ((i % meta_bg_size) == (meta_bg_size-1)))
                                mark_fs_metablock(rfs, meta_bmap, i,
                                                  group_blk + has_super);
                }

                /*
                 * Reserve the existing meta blocks that we know
                 * aren't to be moved.
                 *
                 * For flex_bg file systems, in order to avoid
                 * overwriting fs metadata (especially inode table
                 * blocks) belonging to a different block group when
                 * we are relocating the inode tables, we need to
                 * reserve all existing fs metadata blocks.
                 */
                if (ext2fs_block_bitmap_loc(fs, i))
                        ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
                                 ext2fs_block_bitmap_loc(fs, i));
                else if (flex_bg && i < old_fs->group_desc_count)
                        ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
                                 ext2fs_block_bitmap_loc(old_fs, i));

                if (ext2fs_inode_bitmap_loc(fs, i))
                        ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
                                 ext2fs_inode_bitmap_loc(fs, i));
                else if (flex_bg && i < old_fs->group_desc_count)
                        ext2fs_mark_block_bitmap2(rfs->reserve_blocks,
                                 ext2fs_inode_bitmap_loc(old_fs, i));

                if (ext2fs_inode_table_loc(fs, i))
                        ext2fs_mark_block_bitmap_range2(rfs->reserve_blocks,
                                        ext2fs_inode_table_loc(fs, i),
                                        fs->inode_blocks_per_group);
                else if (flex_bg && i < old_fs->group_desc_count)
                        ext2fs_mark_block_bitmap_range2(rfs->reserve_blocks,
                                        ext2fs_inode_table_loc(old_fs, i),
                                        old_fs->inode_blocks_per_group);

                group_blk += rfs->new_fs->super->s_blocks_per_group;
        }

        /* Allocate the missing data structures */
        for (i = 0; i < max_groups; i++) {
                if (ext2fs_inode_table_loc(fs, i) &&
                    ext2fs_inode_bitmap_loc(fs, i) &&
                    ext2fs_block_bitmap_loc(fs, i))
                        continue;

                retval = ext2fs_allocate_group_table(fs, i,
                                                     rfs->reserve_blocks);
                if (retval)
                        goto errout;

                /*
                 * For those structures that have changed, we need to
                 * do bookkeeping.
                 */
                if (ext2fs_block_bitmap_loc(old_fs, i) !=
                    (blk = ext2fs_block_bitmap_loc(fs, i))) {
                        ext2fs_block_alloc_stats2(fs, blk, +1);
                        if (blk < ext2fs_blocks_count(old_fs->super) &&
                            ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
                            !ext2fs_test_block_bitmap2(meta_bmap, blk))
                                ext2fs_mark_block_bitmap2(rfs->move_blocks,
                                                         blk);
                }
                if (ext2fs_inode_bitmap_loc(old_fs, i) !=
                    (blk = ext2fs_inode_bitmap_loc(fs, i))) {
                        ext2fs_block_alloc_stats2(fs, blk, +1);
                        if (blk < ext2fs_blocks_count(old_fs->super) &&
                            ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
                            !ext2fs_test_block_bitmap2(meta_bmap, blk))
                                ext2fs_mark_block_bitmap2(rfs->move_blocks,
                                                         blk);
                }

                /*
                 * 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.
                 */
                if (ext2fs_inode_table_loc(fs, i) == ext2fs_inode_table_loc(old_fs, i))
                        continue;       /* inode table not moved */

                rfs->needed_blocks += fs->inode_blocks_per_group;

                /*
                 * Mark the new inode table as in use in the new block
                 * allocation bitmap, and move any blocks that might
                 * be necessary.
                 */
                for (blk = ext2fs_inode_table_loc(fs, i), j=0;
                     j < fs->inode_blocks_per_group ; j++, blk++) {
                        ext2fs_block_alloc_stats2(fs, blk, +1);
                        if (blk < ext2fs_blocks_count(old_fs->super) &&
                            ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
                            !ext2fs_test_block_bitmap2(meta_bmap, blk))
                                ext2fs_mark_block_bitmap2(rfs->move_blocks,
                                                         blk);
                }

                /*
                 * Make sure the old inode table is reserved in the
                 * block reservation bitmap.
                 */
                for (blk = ext2fs_inode_table_loc(rfs->old_fs, i), j=0;
                     j < fs->inode_blocks_per_group ; j++, blk++)
                        ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
        }
        retval = 0;

errout:
        if (new_meta_bmap)
                ext2fs_free_block_bitmap(new_meta_bmap);
        if (meta_bmap)
                ext2fs_free_block_bitmap(meta_bmap);

        return retval;
}

/*
 * This helper function tries to allocate a new block.  We try to
 * avoid hitting the original group descriptor blocks at least at
 * first, since we want to make it possible to recover from a badly
 * aborted resize operation as much as possible.
 *
 * In the future, I may further modify this routine to balance out
 * where we get the new blocks across the various block groups.
 * Ideally we would allocate blocks that corresponded with the block
 * group of the containing inode, and keep contiguous blocks
 * together.  However, this very difficult to do efficiently, since we
 * don't have the necessary information up front.
 */

#define AVOID_OLD       1
#define DESPERATION     2

static void init_block_alloc(ext2_resize_t rfs)
{
        rfs->alloc_state = AVOID_OLD;
        rfs->new_blk = rfs->new_fs->super->s_first_data_block;
#if 0
        /* HACK for testing */
        if (ext2fs_blocks_count(rfs->new_fs->super) >
            ext2fs_blocks_count(rfs->old_fs->super))
                rfs->new_blk = ext2fs_blocks_count(rfs->old_fs->super);
#endif
}

static blk64_t get_new_block(ext2_resize_t rfs)
{
        ext2_filsys     fs = rfs->new_fs;

        while (1) {
                if (rfs->new_blk >= ext2fs_blocks_count(fs->super)) {
                        if (rfs->alloc_state == DESPERATION)
                                return 0;

#ifdef RESIZE2FS_DEBUG
                        if (rfs->flags & RESIZE_DEBUG_BMOVE)
                                printf("Going into desperation mode "
                                       "for block allocations\n");
#endif
                        rfs->alloc_state = DESPERATION;
                        rfs->new_blk = fs->super->s_first_data_block;
                        continue;
                }
                if (ext2fs_test_block_bitmap2(fs->block_map, rfs->new_blk) ||
                    ext2fs_test_block_bitmap2(rfs->reserve_blocks,
                                             rfs->new_blk) ||
                    ((rfs->alloc_state == AVOID_OLD) &&
                     (rfs->new_blk < ext2fs_blocks_count(rfs->old_fs->super)) &&
                     ext2fs_test_block_bitmap2(rfs->old_fs->block_map,
                                              rfs->new_blk))) {
                        rfs->new_blk++;
                        continue;
                }
                return rfs->new_blk;
        }
}

static errcode_t resize2fs_get_alloc_block(ext2_filsys fs,
                                           blk64_t goal EXT2FS_ATTR((unused)),
                                           blk64_t *ret)
{
        ext2_resize_t rfs = (ext2_resize_t) fs->priv_data;
        blk64_t blk;
        int group;

        blk = get_new_block(rfs);
        if (!blk)
                return ENOSPC;

#ifdef RESIZE2FS_DEBUG
        if (rfs->flags & 0xF)
                printf("get_alloc_block allocating %llu\n",
                       (unsigned long long) blk);
#endif

        ext2fs_mark_block_bitmap2(rfs->old_fs->block_map, blk);
        ext2fs_mark_block_bitmap2(rfs->new_fs->block_map, blk);

        group = ext2fs_group_of_blk2(rfs->old_fs, blk);
        ext2fs_clear_block_uninit(rfs->old_fs, group);
        group = ext2fs_group_of_blk2(rfs->new_fs, blk);
        ext2fs_clear_block_uninit(rfs->new_fs, group);

        *ret = (blk64_t) blk;
        return 0;
}

static errcode_t block_mover(ext2_resize_t rfs)
{
        blk64_t                 blk, old_blk, new_blk;
        ext2_filsys             fs = rfs->new_fs;
        ext2_filsys             old_fs = rfs->old_fs;
        errcode_t               retval;
        __u64                   c, size;
        int                     to_move, moved;
        ext2_badblocks_list     badblock_list = 0;
        int                     bb_modified = 0;

        fs->get_alloc_block = resize2fs_get_alloc_block;
        old_fs->get_alloc_block = resize2fs_get_alloc_block;

        retval = ext2fs_read_bb_inode(old_fs, &badblock_list);
        if (retval)
                return retval;

        new_blk = fs->super->s_first_data_block;
        if (!rfs->itable_buf) {
                retval = ext2fs_get_array(fs->blocksize,
                                        fs->inode_blocks_per_group,
                                        &rfs->itable_buf);
                if (retval)
                        return retval;
        }
        retval = ext2fs_create_extent_table(&rfs->bmap, 0);
        if (retval)
                return retval;

        /*
         * The first step is to figure out where all of the blocks
         * will go.
         */
        to_move = moved = 0;
        init_block_alloc(rfs);
        for (blk = B2C(old_fs->super->s_first_data_block);
             blk < ext2fs_blocks_count(old_fs->super);
             blk += EXT2FS_CLUSTER_RATIO(fs)) {
                if (!ext2fs_test_block_bitmap2(old_fs->block_map, blk))
                        continue;
                if (!ext2fs_test_block_bitmap2(rfs->move_blocks, blk))
                        continue;
                if (ext2fs_badblocks_list_test(badblock_list, blk)) {
                        ext2fs_badblocks_list_del(badblock_list, blk);
                        bb_modified++;
                        continue;
                }

                new_blk = get_new_block(rfs);
                if (!new_blk) {
                        retval = ENOSPC;
                        goto errout;
                }
                ext2fs_block_alloc_stats2(fs, new_blk, +1);
                ext2fs_add_extent_entry(rfs->bmap, B2C(blk), B2C(new_blk));
                to_move++;
        }

        if (to_move == 0) {
                if (rfs->bmap) {
                        ext2fs_free_extent_table(rfs->bmap);
                        rfs->bmap = 0;
                }
                retval = 0;
                goto errout;
        }

        /*
         * Step two is to actually move the blocks
         */
        retval =  ext2fs_iterate_extent(rfs->bmap, 0, 0, 0);
        if (retval) goto errout;

        if (rfs->progress) {
                retval = (rfs->progress)(rfs, E2_RSZ_BLOCK_RELOC_PASS,
                                         0, to_move);
                if (retval)
                        goto errout;
        }
        while (1) {
                retval = ext2fs_iterate_extent(rfs->bmap, &old_blk, &new_blk, &size);
                if (retval) goto errout;
                if (!size)
                        break;
                old_blk = C2B(old_blk);
                new_blk = C2B(new_blk);
                size = C2B(size);
#ifdef RESIZE2FS_DEBUG
                if (rfs->flags & RESIZE_DEBUG_BMOVE)
                        printf("Moving %llu blocks %llu->%llu\n",
                               (unsigned long long) size,
                               (unsigned long long) old_blk,
                               (unsigned long long) new_blk);
#endif
                do {
                        c = size;
                        if (c > fs->inode_blocks_per_group)
                                c = fs->inode_blocks_per_group;
                        retval = io_channel_read_blk64(fs->io, old_blk, c,
                                                       rfs->itable_buf);
                        if (retval) goto errout;
                        retval = io_channel_write_blk64(fs->io, new_blk, c,
                                                        rfs->itable_buf);
                        if (retval) goto errout;
                        size -= c;
                        new_blk += c;
                        old_blk += c;
                        moved += c;
                        if (rfs->progress) {
                                io_channel_flush(fs->io);
                                retval = (rfs->progress)(rfs,
                                                E2_RSZ_BLOCK_RELOC_PASS,
                                                moved, to_move);
                                if (retval)
                                        goto errout;
                        }
                } while (size > 0);
                io_channel_flush(fs->io);
        }

errout:
        if (badblock_list) {
                if (!retval && bb_modified)
                        retval = ext2fs_update_bb_inode(old_fs,
                                                        badblock_list);
                ext2fs_badblocks_list_free(badblock_list);
        }
        return retval;
}


/* --------------------------------------------------------------------
 *
 * Resize processing, phase 3
 *
 * --------------------------------------------------------------------
 */


/*
 * The extent translation table is stored in clusters so we need to
 * take special care when mapping a source block number to its
 * destination block number.
 */
static __u64 extent_translate(ext2_filsys fs, ext2_extent extent, __u64 old_loc)
{
        __u64 new_block = C2B(ext2fs_extent_translate(extent, B2C(old_loc)));

        if (new_block != 0)
                new_block += old_loc & (EXT2FS_CLUSTER_RATIO(fs) - 1);
        return new_block;
}

struct process_block_struct {
        ext2_resize_t           rfs;
        ext2_ino_t              ino;
        ext2_ino_t              old_ino;
        struct ext2_inode *     inode;
        errcode_t               error;
        int                     is_dir;
        int                     changed;
        int                     has_extents;
};

static int process_block(ext2_filsys fs, blk64_t        *block_nr,
                         e2_blkcnt_t blockcnt,
                         blk64_t ref_block EXT2FS_ATTR((unused)),
                         int ref_offset EXT2FS_ATTR((unused)), void *priv_data)
{
        struct process_block_struct *pb;
        errcode_t       retval;
        blk64_t         block, new_block;
        int             ret = 0;

        pb = (struct process_block_struct *) priv_data;
        block = *block_nr;
        if (pb->rfs->bmap) {
                new_block = extent_translate(fs, pb->rfs->bmap, block);
                if (new_block) {
                        *block_nr = new_block;
                        ret |= BLOCK_CHANGED;
                        pb->changed = 1;
#ifdef RESIZE2FS_DEBUG
                        if (pb->rfs->flags & RESIZE_DEBUG_BMOVE)
                                printf("ino=%u, blockcnt=%lld, %llu->%llu\n",
                                       pb->old_ino, (long long) blockcnt,
                                       (unsigned long long) block,
                                       (unsigned long long) new_block);
#endif
                        block = new_block;
                }
        }

        if (pb->is_dir) {
                retval = ext2fs_add_dir_block2(fs->dblist, pb->ino,
                                               block, (int) blockcnt);
                if (retval) {
                        pb->error = retval;
                        ret |= BLOCK_ABORT;
                }
        }
        return ret;
}

/*
 * Progress callback
 */
static errcode_t progress_callback(ext2_filsys fs,
                                   ext2_inode_scan scan EXT2FS_ATTR((unused)),
                                   dgrp_t group, void * priv_data)
{
        ext2_resize_t rfs = (ext2_resize_t) priv_data;
        errcode_t               retval;

        /*
         * This check is to protect against old ext2 libraries.  It
         * shouldn't be needed against new libraries.
         */
        if ((group+1) == 0)
                return 0;

        if (rfs->progress) {
                io_channel_flush(fs->io);
                retval = (rfs->progress)(rfs, E2_RSZ_INODE_SCAN_PASS,
                                         group+1, fs->group_desc_count);
                if (retval)
                        return retval;
        }

        return 0;
}

static errcode_t migrate_ea_block(ext2_resize_t rfs, ext2_ino_t ino,
                                  struct ext2_inode *inode, int *changed)
{
        char *buf = NULL;
        blk64_t new_block;
        errcode_t err = 0;

        /* No EA block or no remapping?  Quit early. */
        if (ext2fs_file_acl_block(rfs->old_fs, inode) == 0 || !rfs->bmap)
                return 0;
        new_block = extent_translate(rfs->old_fs, rfs->bmap,
                ext2fs_file_acl_block(rfs->old_fs, inode));
        if (new_block == 0)
                return 0;

        /* Set the new ACL block */
        ext2fs_file_acl_block_set(rfs->old_fs, inode, new_block);

        /* Update checksum */
        if (ext2fs_has_feature_metadata_csum(rfs->new_fs->super)) {
                err = ext2fs_get_mem(rfs->old_fs->blocksize, &buf);
                if (err)
                        return err;
                rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
                err = ext2fs_read_ext_attr3(rfs->old_fs, new_block, buf, ino);
                rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
                if (err)
                        goto out;
                err = ext2fs_write_ext_attr3(rfs->old_fs, new_block, buf, ino);
                if (err)
                        goto out;
        }
        *changed = 1;

out:
        ext2fs_free_mem(&buf);
        return err;
}

static void quiet_com_err_proc(const char *whoami EXT2FS_ATTR((unused)),
                               errcode_t code EXT2FS_ATTR((unused)),
                               const char *fmt EXT2FS_ATTR((unused)),
                               va_list args EXT2FS_ATTR((unused)))
{
}

static int fix_ea_entries(ext2_extent imap, struct ext2_ext_attr_entry *entry,
                          struct ext2_ext_attr_entry *end, ext2_ino_t last_ino)
{
        int modified = 0;
        ext2_ino_t new_ino;

        while (entry < end && !EXT2_EXT_IS_LAST_ENTRY(entry)) {
                if (entry->e_value_inum > last_ino) {
                        new_ino = ext2fs_extent_translate(imap,
                                                          entry->e_value_inum);
                        entry->e_value_inum = new_ino;
                        modified = 1;
                }
                entry = EXT2_EXT_ATTR_NEXT(entry);
        }
        return modified;
}

static int fix_ea_ibody_entries(ext2_extent imap,
                                struct ext2_inode_large *inode, int inode_size,
                                ext2_ino_t last_ino)
{
        struct ext2_ext_attr_entry *start, *end;
        __u32 *ea_magic;

        if (inode->i_extra_isize == 0)
                return 0;

        ea_magic = (__u32 *)((char *)inode + EXT2_GOOD_OLD_INODE_SIZE +
                                inode->i_extra_isize);
        if (*ea_magic != EXT2_EXT_ATTR_MAGIC)
                return 0;

        start = (struct ext2_ext_attr_entry *)(ea_magic + 1);
        end = (struct ext2_ext_attr_entry *)((char *)inode + inode_size);

        return fix_ea_entries(imap, start, end, last_ino);
}

static int fix_ea_block_entries(ext2_extent imap, char *block_buf,
                                unsigned int blocksize, ext2_ino_t last_ino)
{
        struct ext2_ext_attr_header *header;
        struct ext2_ext_attr_entry *start, *end;

        header = (struct ext2_ext_attr_header *)block_buf;
        start = (struct ext2_ext_attr_entry *)(header+1);
        end = (struct ext2_ext_attr_entry *)(block_buf + blocksize);

        return fix_ea_entries(imap, start, end, last_ino);
}

/* A simple LRU cache to check recently processed blocks. */
struct blk_cache {
        int cursor;
        blk64_t blks[4];
};

#define BLK_IN_CACHE(b,c) ((b) == (c).blks[0] || (b) == (c).blks[1] || \
                           (b) == (c).blks[2] || (b) == (c).blks[3])
#define BLK_ADD_CACHE(b,c) {                    \
        (c).blks[(c).cursor] = (b);             \
        (c).cursor = ((c).cursor + 1) % 4;      \
}

static errcode_t fix_ea_inode_refs(ext2_resize_t rfs, struct ext2_inode *inode,
                                   char *block_buf, ext2_ino_t last_ino)
{
        ext2_filsys     fs = rfs->new_fs;
        ext2_inode_scan scan = NULL;
        ext2_ino_t      ino;
        int             inode_size = EXT2_INODE_SIZE(fs->super);
        blk64_t         blk;
        int             modified;
        struct blk_cache blk_cache;
        struct ext2_ext_attr_header *header;
        errcode_t               retval;

        memset(&blk_cache, 0, sizeof(blk_cache));

        header = (struct ext2_ext_attr_header *)block_buf;

        retval = ext2fs_open_inode_scan(fs, 0, &scan);
        if (retval)
                goto out;

        while (1) {
                retval = ext2fs_get_next_inode_full(scan, &ino, inode,
                                                    inode_size);
                if (retval)
                        goto out;
                if (!ino)
                        break;

                if (inode->i_links_count == 0 && ino != EXT2_RESIZE_INO)
                        continue; /* inode not in use */

                if (inode_size != EXT2_GOOD_OLD_INODE_SIZE) {
                        modified = fix_ea_ibody_entries(rfs->imap,
                                        (struct ext2_inode_large *)inode,
                                        inode_size, last_ino);
                        if (modified) {
                                retval = ext2fs_write_inode_full(fs, ino, inode,
                                                                 inode_size);
                                if (retval)
                                        goto out;
                        }
                }

                blk = ext2fs_file_acl_block(fs, inode);
                if (blk && !BLK_IN_CACHE(blk, blk_cache)) {
                        retval = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
                        if (retval)
                                goto out;

                        modified = fix_ea_block_entries(rfs->imap, block_buf,
                                                        fs->blocksize,
                                                        last_ino);
                        if (modified) {
                                retval = ext2fs_write_ext_attr3(fs, blk,
                                                                block_buf, ino);
                                if (retval)
                                        goto out;
                                /*
                                 * If refcount is greater than 1, we might see
                                 * the same block referenced by other inodes
                                 * later.
                                 */
                                if (header->h_refcount > 1)
                                        BLK_ADD_CACHE(blk, blk_cache);
                        }
                }
        }
        retval = 0;
out:
        if (scan)
                ext2fs_close_inode_scan(scan);
        return retval;

}
static errcode_t inode_scan_and_fix(ext2_resize_t rfs)
{
        struct process_block_struct     pb;
        ext2_ino_t              ino, new_inode;
        struct ext2_inode       *inode = NULL;
        ext2_inode_scan         scan = NULL;
        errcode_t               retval;
        char                    *block_buf = 0;
        ext2_ino_t              start_to_move;
        int                     inode_size;
        int                     update_ea_inode_refs = 0;

        if ((rfs->old_fs->group_desc_count <=
             rfs->new_fs->group_desc_count) &&
            !rfs->bmap)
                return 0;

        set_com_err_hook(quiet_com_err_proc);

        retval = ext2fs_open_inode_scan(rfs->old_fs, 0, &scan);
        if (retval) goto errout;

        retval = ext2fs_init_dblist(rfs->old_fs, 0);
        if (retval) goto errout;
        retval = ext2fs_get_array(rfs->old_fs->blocksize, 3, &block_buf);
        if (retval) goto errout;

        start_to_move = (rfs->new_fs->group_desc_count *
                         rfs->new_fs->super->s_inodes_per_group);

        if (rfs->progress) {
                retval = (rfs->progress)(rfs, E2_RSZ_INODE_SCAN_PASS,
                                         0, rfs->old_fs->group_desc_count);
                if (retval)
                        goto errout;
        }
        ext2fs_set_inode_callback(scan, progress_callback, (void *) rfs);
        pb.rfs = rfs;
        pb.inode = inode;
        pb.error = 0;
        new_inode = EXT2_FIRST_INODE(rfs->new_fs->super);
        inode_size = EXT2_INODE_SIZE(rfs->new_fs->super);
        inode = malloc(inode_size);
        if (!inode) {
                retval = ENOMEM;
                goto errout;
        }
        /*
         * First, copy all of the inodes that need to be moved
         * elsewhere in the inode table
         */
        while (1) {
                retval = ext2fs_get_next_inode_full(scan, &ino, inode, inode_size);
                if (retval) goto errout;
                if (!ino)
                        break;

                if (inode->i_links_count == 0 && ino != EXT2_RESIZE_INO)
                        continue; /* inode not in use */

                pb.is_dir = LINUX_S_ISDIR(inode->i_mode);
                pb.changed = 0;

                /* Remap EA block */
                retval = migrate_ea_block(rfs, ino, inode, &pb.changed);
                if (retval)
                        goto errout;

                new_inode = ino;
                if (ino <= start_to_move)
                        goto remap_blocks; /* Don't need to move inode. */

                /*
                 * Find a new inode.  Now that extents and directory blocks
                 * are tied to the inode number through the checksum, we must
                 * set up the new inode before we start rewriting blocks.
                 */
                retval = ext2fs_new_inode(rfs->new_fs, 0, 0, 0, &new_inode);
                if (retval)
                        goto errout;

                ext2fs_inode_alloc_stats2(rfs->new_fs, new_inode, +1,
                                          pb.is_dir);
                /*
                 * i_ctime field in xattr inodes contain a portion of the ref
                 * count, do not overwrite.
                 */
                if (inode->i_flags & EXT4_EA_INODE_FL)
                        update_ea_inode_refs = 1;
                else
                        inode->i_ctime = time(0);

                retval = ext2fs_write_inode_full(rfs->old_fs, new_inode,
                                                inode, inode_size);
                if (retval)
                        goto errout;
                pb.changed = 0;

#ifdef RESIZE2FS_DEBUG
                if (rfs->flags & RESIZE_DEBUG_INODEMAP)
                        printf("Inode moved %u->%u\n", ino, new_inode);
#endif
                if (!rfs->imap) {
                        retval = ext2fs_create_extent_table(&rfs->imap, 0);
                        if (retval)
                                goto errout;
                }
                ext2fs_add_extent_entry(rfs->imap, ino, new_inode);

remap_blocks:
                if (pb.changed)
                        retval = ext2fs_write_inode_full(rfs->old_fs,
                                                         new_inode,
                                                         inode, inode_size);
                if (retval)
                        goto errout;

                /*
                 * Update inodes to point to new blocks; schedule directory
                 * blocks for inode remapping.  Need to write out dir blocks
                 * with new inode numbers if we have metadata_csum enabled.
                 */
                rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
                if (ext2fs_inode_has_valid_blocks2(rfs->old_fs, inode) &&
                    (rfs->bmap || pb.is_dir)) {
                        pb.ino = new_inode;
                        pb.old_ino = ino;
                        pb.has_extents = inode->i_flags & EXT4_EXTENTS_FL;
                        retval = ext2fs_block_iterate3(rfs->old_fs,
                                                       new_inode, 0, block_buf,
                                                       process_block, &pb);
                        if (retval)
                                goto errout;
                        if (pb.error) {
                                retval = pb.error;
                                goto errout;
                        }
                } else if ((inode->i_flags & EXT4_INLINE_DATA_FL) &&
                           (rfs->bmap || pb.is_dir)) {
                        /* inline data dir; update it too */
                        retval = ext2fs_add_dir_block2(rfs->old_fs->dblist,
                                                       new_inode, 0, 0);
                        if (retval)
                                goto errout;
                }

                /* Fix up extent block checksums with the new inode number */
                if (ext2fs_has_feature_metadata_csum(rfs->old_fs->super) &&
                    (inode->i_flags & EXT4_EXTENTS_FL)) {
                        retval = ext2fs_fix_extents_checksums(rfs->old_fs,
                                                              new_inode, NULL);
                        if (retval)
                                goto errout;
                }
        }

        if (update_ea_inode_refs &&
            ext2fs_has_feature_ea_inode(rfs->new_fs->super)) {
                retval = fix_ea_inode_refs(rfs, inode, block_buf,
                                           start_to_move);
                if (retval)
                        goto errout;
        }
        io_channel_flush(rfs->old_fs->io);

errout:
        reset_com_err_hook();
        rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
        if (rfs->bmap) {
                ext2fs_free_extent_table(rfs->bmap);
                rfs->bmap = 0;
        }
        if (scan)
                ext2fs_close_inode_scan(scan);
        if (block_buf)
                ext2fs_free_mem(&block_buf);
        free(inode);
        return retval;
}

/* --------------------------------------------------------------------
 *
 * Resize processing, phase 4.
 *
 * --------------------------------------------------------------------
 */

struct istruct {
        ext2_resize_t rfs;
        errcode_t       err;
        unsigned int    max_dirs;
        unsigned int    num;
};

static int check_and_change_inodes(ext2_ino_t dir,
                                   int entry EXT2FS_ATTR((unused)),
                                   struct ext2_dir_entry *dirent, int offset,
                                   int  blocksize EXT2FS_ATTR((unused)),
                                   char *buf EXT2FS_ATTR((unused)),
                                   void *priv_data)
{
        struct istruct *is = (struct istruct *) priv_data;
        struct ext2_inode       inode;
        ext2_ino_t              new_inode;
        errcode_t               retval;
        int                     ret = 0;

        if (is->rfs->progress && offset == 0) {
                io_channel_flush(is->rfs->old_fs->io);
                is->err = (is->rfs->progress)(is->rfs,
                                              E2_RSZ_INODE_REF_UPD_PASS,
                                              ++is->num, is->max_dirs);
                if (is->err)
                        return DIRENT_ABORT;
        }

        /*
         * If we have checksums enabled and the inode wasn't present in the
         * old fs, then we must rewrite all dir blocks with new checksums.
         */
        if (ext2fs_has_feature_metadata_csum(is->rfs->old_fs->super) &&
            !ext2fs_test_inode_bitmap2(is->rfs->old_fs->inode_map, dir))
                ret |= DIRENT_CHANGED;

        if (!dirent->inode)
                return ret;

        new_inode = ext2fs_extent_translate(is->rfs->imap, dirent->inode);

        if (!new_inode)
                return ret;
#ifdef RESIZE2FS_DEBUG
        if (is->rfs->flags & RESIZE_DEBUG_INODEMAP)
                printf("Inode translate (dir=%u, name=%.*s, %u->%u)\n",
                       dir, ext2fs_dirent_name_len(dirent), dirent->name,
                       dirent->inode, new_inode);
#endif

        dirent->inode = new_inode;

        /* Update the directory mtime and ctime */
        retval = ext2fs_read_inode(is->rfs->old_fs, dir, &inode);
        if (retval == 0) {
                inode.i_mtime = inode.i_ctime = time(0);
                is->err = ext2fs_write_inode(is->rfs->old_fs, dir, &inode);
                if (is->err)
                        return ret | DIRENT_ABORT;
        }

        return ret | DIRENT_CHANGED;
}

static errcode_t inode_ref_fix(ext2_resize_t rfs)
{
        errcode_t               retval;
        struct istruct          is;

        if (!rfs->imap)
                return 0;

        /*
         * Now, we iterate over all of the directories to update the
         * inode references
         */
        is.num = 0;
        is.max_dirs = ext2fs_dblist_count2(rfs->old_fs->dblist);
        is.rfs = rfs;
        is.err = 0;

        if (rfs->progress) {
                retval = (rfs->progress)(rfs, E2_RSZ_INODE_REF_UPD_PASS,
                                         0, is.max_dirs);
                if (retval)
                        goto errout;
        }

        rfs->old_fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
        retval = ext2fs_dblist_dir_iterate(rfs->old_fs->dblist,
                                           DIRENT_FLAG_INCLUDE_EMPTY, 0,
                                           check_and_change_inodes, &is);
        rfs->old_fs->flags &= ~EXT2_FLAG_IGNORE_CSUM_ERRORS;
        if (retval)
                goto errout;
        if (is.err) {
                retval = is.err;
                goto errout;
        }

        if (rfs->progress && (is.num < is.max_dirs))
                (rfs->progress)(rfs, E2_RSZ_INODE_REF_UPD_PASS,
                                is.max_dirs, is.max_dirs);

errout:
        ext2fs_free_extent_table(rfs->imap);
        rfs->imap = 0;
        return retval;
}


/* --------------------------------------------------------------------
 *
 * Resize processing, phase 5.
 *
 * In this phase we actually move the inode table around, and then
 * update the summary statistics.  This is scary, since aborting here
 * will potentially scramble the filesystem.  (We are moving the
 * inode tables around in place, and so the potential for lost data,
 * or at the very least scrambling the mapping between filenames and
 * inode numbers is very high in case of a power failure here.)
 * --------------------------------------------------------------------
 */


/*
 * 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.
 */
static errcode_t move_itables(ext2_resize_t rfs)
{
        int             n, num, size;
        long long       diff;
        dgrp_t          i, max_groups;
        ext2_filsys     fs = rfs->new_fs;
        char            *cp;
        blk64_t         old_blk, new_blk, blk, cluster_freed;
        errcode_t       retval;
        int             to_move, moved;
        unsigned int    j;
        ext2fs_block_bitmap     new_bmap = NULL;

        max_groups = fs->group_desc_count;
        if (max_groups > rfs->old_fs->group_desc_count)
                max_groups = rfs->old_fs->group_desc_count;

        size = fs->blocksize * fs->inode_blocks_per_group;
        if (!rfs->itable_buf) {
                retval = ext2fs_get_mem(size, &rfs->itable_buf);
                if (retval)
                        return retval;
        }

        if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
                retval = ext2fs_allocate_block_bitmap(fs, _("new meta blocks"),
                                                      &new_bmap);
                if (retval)
                        return retval;

                retval = mark_table_blocks(fs, new_bmap);
                if (retval)
                        goto errout;
        }

        /*
         * Figure out how many inode tables we need to move
         */
        to_move = moved = 0;
        for (i=0; i < max_groups; i++)
                if (ext2fs_inode_table_loc(rfs->old_fs, i) !=
                    ext2fs_inode_table_loc(fs, i))
                        to_move++;

        if (to_move == 0) {
                retval = 0;
                goto errout;
        }

        if (rfs->progress) {
                retval = rfs->progress(rfs, E2_RSZ_MOVE_ITABLE_PASS,
                                       0, to_move);
                if (retval)
                        goto errout;
        }

        rfs->old_fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;

        for (i=0; i < max_groups; i++) {
                old_blk = ext2fs_inode_table_loc(rfs->old_fs, i);
                new_blk = ext2fs_inode_table_loc(fs, i);
                diff = new_blk - old_blk;

#ifdef RESIZE2FS_DEBUG
                if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
                        printf("Itable move group %d block %llu->%llu (diff %lld)\n",
                               i, (unsigned long long) old_blk,
                               (unsigned long long) new_blk, diff);
#endif

                if (!diff)
                        continue;
                if (diff < 0)
                        diff = 0;

                retval = io_channel_read_blk64(fs->io, old_blk,
                                               fs->inode_blocks_per_group,
                                               rfs->itable_buf);
                if (retval)
                        goto errout;
                /*
                 * The end of the inode table segment often contains
                 * all zeros, and we're often only moving the inode
                 * table down a block or two.  If so, we can optimize
                 * things by not rewriting blocks that we know to be zero
                 * already.
                 */
                for (cp = rfs->itable_buf+size-1, n=0; n < size; n++, cp--)
                        if (*cp)
                                break;
                n = n >> EXT2_BLOCK_SIZE_BITS(fs->super);
#ifdef RESIZE2FS_DEBUG
                if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
                        printf("%d blocks of zeros...\n", n);
#endif
                num = fs->inode_blocks_per_group;
                if (n > diff)
                        num -= n;

                retval = io_channel_write_blk64(fs->io, new_blk,
                                                num, rfs->itable_buf);
                if (retval) {
                        io_channel_write_blk64(fs->io, old_blk,
                                               num, rfs->itable_buf);
                        goto errout;
                }
                if (n > diff) {
                        retval = io_channel_write_blk64(fs->io,
                              old_blk + fs->inode_blocks_per_group,
                              diff, (rfs->itable_buf +
                                     (fs->inode_blocks_per_group - diff) *
                                     fs->blocksize));
                        if (retval)
                                goto errout;
                }

                for (blk = ext2fs_inode_table_loc(rfs->old_fs, i), j=0;
                     j < fs->inode_blocks_per_group;) {
                        if (new_bmap == NULL ||
                            !ext2fs_test_block_bitmap2(new_bmap, blk)) {
                                ext2fs_block_alloc_stats2(fs, blk, -1);
                                cluster_freed = EXT2FS_CLUSTER_RATIO(fs) -
                                                (blk & EXT2FS_CLUSTER_MASK(fs));
                                blk += cluster_freed;
                                j += cluster_freed;
                                continue;
                        }
                        blk++;
                        j++;
                }

                ext2fs_inode_table_loc_set(rfs->old_fs, i, new_blk);
                ext2fs_group_desc_csum_set(rfs->old_fs, i);
                ext2fs_mark_super_dirty(rfs->old_fs);
                ext2fs_flush(rfs->old_fs);

                if (rfs->progress) {
                        retval = rfs->progress(rfs, E2_RSZ_MOVE_ITABLE_PASS,
                                               ++moved, to_move);
                        if (retval)
                                goto errout;
                }
        }
        mark_table_blocks(fs, fs->block_map);
        ext2fs_flush(fs);
#ifdef RESIZE2FS_DEBUG
        if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
                printf("Inode table move finished.\n");
#endif
        retval = 0;

errout:
        if (new_bmap)
                ext2fs_free_block_bitmap(new_bmap);
        return retval;
}

/*
 * This function is used when expanding a file system.  It frees the
 * superblock and block group descriptor blocks from the block group
 * which is no longer the last block group.
 */
static errcode_t clear_sparse_super2_last_group(ext2_resize_t rfs)
{
        ext2_filsys     fs = rfs->new_fs;
        ext2_filsys     old_fs = rfs->old_fs;
        errcode_t       retval;
        dgrp_t          old_last_bg = rfs->old_fs->group_desc_count - 1;
        dgrp_t          last_bg = fs->group_desc_count - 1;
        blk64_t         sb, old_desc;
        blk_t           num;

        if (!ext2fs_has_feature_sparse_super2(fs->super))
                return 0;

        if (last_bg <= old_last_bg)
                return 0;

        if (fs->super->s_backup_bgs[0] == old_fs->super->s_backup_bgs[0] &&
            fs->super->s_backup_bgs[1] == old_fs->super->s_backup_bgs[1])
                return 0;

        if (old_fs->super->s_backup_bgs[0] != old_last_bg &&
            old_fs->super->s_backup_bgs[1] != old_last_bg)
                return 0;

        if (fs->super->s_backup_bgs[0] == old_last_bg ||
            fs->super->s_backup_bgs[1] == old_last_bg)
                return 0;

        if (old_last_bg == 0)
                return 0;

        retval = ext2fs_super_and_bgd_loc2(rfs->old_fs, old_last_bg,
                                           &sb, &old_desc, NULL, &num);
        if (retval)
                return retval;

        if (sb)
                ext2fs_unmark_block_bitmap2(fs->block_map, sb);
        if (old_desc)
                ext2fs_unmark_block_bitmap_range2(fs->block_map, old_desc, num);
        return 0;
}

/*
 * This function is used when shrinking a file system.  We need to
 * utilize blocks from what will be the new last block group for the
 * backup superblock and block group descriptor blocks.
 * Unfortunately, those blocks may be used by other files or fs
 * metadata blocks.  We need to mark them as being in use.
 */
static errcode_t reserve_sparse_super2_last_group(ext2_resize_t rfs,
                                                 ext2fs_block_bitmap meta_bmap)
{
        ext2_filsys     fs = rfs->new_fs;
        ext2_filsys     old_fs = rfs->old_fs;
        errcode_t       retval;
        dgrp_t          old_last_bg = rfs->old_fs->group_desc_count - 1;
        dgrp_t          last_bg = fs->group_desc_count - 1;
        dgrp_t          g;
        blk64_t         blk, sb, old_desc;
        blk_t           i, num;
        int             realloc = 0;

        if (!ext2fs_has_feature_sparse_super2(fs->super))
                return 0;

        if (last_bg >= old_last_bg)
                return 0;

        if (fs->super->s_backup_bgs[0] == old_fs->super->s_backup_bgs[0] &&
            fs->super->s_backup_bgs[1] == old_fs->super->s_backup_bgs[1])
                return 0;

        if (fs->super->s_backup_bgs[0] != last_bg &&
            fs->super->s_backup_bgs[1] != last_bg)
                return 0;

        if (old_fs->super->s_backup_bgs[0] == last_bg ||
            old_fs->super->s_backup_bgs[1] == last_bg)
                return 0;

        retval = ext2fs_super_and_bgd_loc2(rfs->new_fs, last_bg,
                                           &sb, &old_desc, NULL, &num);
        if (retval)
                return retval;

        if (last_bg && !sb) {
                fputs(_("Should never happen!  No sb in last super_sparse bg?\n"),
                      stderr);
                exit(1);
        }
        if (old_desc && old_desc != sb+1) {
                fputs(_("Should never happen!  Unexpected old_desc in "
                        "super_sparse bg?\n"),
                      stderr);
                exit(1);
        }
        num = (old_desc) ? num : 1;

        /* Reserve the backup blocks */
        ext2fs_mark_block_bitmap_range2(fs->block_map, sb, num);

        for (g = 0; g < fs->group_desc_count; g++) {
                blk64_t mb;

                mb = ext2fs_block_bitmap_loc(fs, g);
                if ((mb >= sb) && (mb < sb + num)) {
                        ext2fs_block_bitmap_loc_set(fs, g, 0);
                        realloc = 1;
                }
                mb = ext2fs_inode_bitmap_loc(fs, g);
                if ((mb >= sb) && (mb < sb + num)) {
                        ext2fs_inode_bitmap_loc_set(fs, g, 0);
                        realloc = 1;
                }
                mb = ext2fs_inode_table_loc(fs, g);
                if ((mb < sb + num) &&
                    (sb < mb + fs->inode_blocks_per_group)) {
                        ext2fs_inode_table_loc_set(fs, g, 0);
                        realloc = 1;
                }
                if (realloc) {
                        retval = ext2fs_allocate_group_table(fs, g, 0);
                        if (retval)
                                return retval;
                }
        }

        for (blk = sb, i = 0; i < num; blk++, i++) {
                if (ext2fs_test_block_bitmap2(old_fs->block_map, blk) &&
                    !ext2fs_test_block_bitmap2(meta_bmap, blk)) {
                        ext2fs_mark_block_bitmap2(rfs->move_blocks, blk);
                        rfs->needed_blocks++;
                }
                ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk);
        }
        return 0;
}

/*
 * Fix the resize inode
 */
static errcode_t fix_resize_inode(ext2_filsys fs)
{
        struct ext2_inode       inode;
        errcode_t               retval;

        if (!ext2fs_has_feature_resize_inode(fs->super))
                return 0;

        retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
        if (retval) goto errout;

        ext2fs_iblk_set(fs, &inode, 1);

        retval = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
        if (retval) goto errout;

        if (!inode.i_block[EXT2_DIND_BLOCK]) {
                /*
                 * Avoid zeroing out block #0; that's rude.  This
                 * should never happen anyway since the filesystem
                 * should be fsck'ed and we assume it is consistent.
                 */
                fprintf(stderr, "%s",
                        _("Should never happen: resize inode corrupt!\n"));
                exit(1);
        }

        retval = ext2fs_zero_blocks2(fs, inode.i_block[EXT2_DIND_BLOCK], 1,
                                     NULL, NULL);
        if (retval)
                goto errout;

        retval = ext2fs_create_resize_inode(fs);
        if (retval)
                goto errout;

errout:
        return retval;
}

/*
 * Finally, recalculate the summary information
 */
static errcode_t resize2fs_calculate_summary_stats(ext2_filsys fs)
{
        blk64_t         blk;
        ext2_ino_t      ino;
        unsigned int    group = 0;
        unsigned int    count = 0;
        blk64_t         total_blocks_free = 0;
        int             total_inodes_free = 0;
        int             group_free = 0;
        int             uninit = 0;
        blk64_t         super_blk, old_desc_blk, new_desc_blk;
        int             old_desc_blocks;

        /*
         * First calculate the block statistics
         */
        uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT);
        ext2fs_super_and_bgd_loc2(fs, group, &super_blk, &old_desc_blk,
                                  &new_desc_blk, 0);
        if (ext2fs_has_feature_meta_bg(fs->super))
                old_desc_blocks = fs->super->s_first_meta_bg;
        else
                old_desc_blocks = fs->desc_blocks +
                        fs->super->s_reserved_gdt_blocks;
        for (blk = B2C(fs->super->s_first_data_block);
             blk < ext2fs_blocks_count(fs->super);
             blk += EXT2FS_CLUSTER_RATIO(fs)) {
                if ((uninit &&
                     !(EQ_CLSTR(blk, super_blk) ||
                       ((old_desc_blk && old_desc_blocks &&
                         GE_CLSTR(blk, old_desc_blk) &&
                         LT_CLSTR(blk, old_desc_blk + old_desc_blocks))) ||
                       ((new_desc_blk && EQ_CLSTR(blk, new_desc_blk))) ||
                       EQ_CLSTR(blk, ext2fs_block_bitmap_loc(fs, group)) ||
                       EQ_CLSTR(blk, ext2fs_inode_bitmap_loc(fs, group)) ||
                       ((GE_CLSTR(blk, ext2fs_inode_table_loc(fs, group)) &&
                         LT_CLSTR(blk, ext2fs_inode_table_loc(fs, group)
                                  + fs->inode_blocks_per_group))))) ||
                    (!ext2fs_fast_test_block_bitmap2(fs->block_map, blk))) {
                        group_free++;
                        total_blocks_free++;
                }
                count++;
                if ((count == fs->super->s_clusters_per_group) ||
                    EQ_CLSTR(blk, ext2fs_blocks_count(fs->super)-1)) {
                        ext2fs_bg_free_blocks_count_set(fs, group, group_free);
                        ext2fs_group_desc_csum_set(fs, group);
                        group++;
                        if (group >= fs->group_desc_count)
                                break;
                        count = 0;
                        group_free = 0;
                        uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT);
                        ext2fs_super_and_bgd_loc2(fs, group, &super_blk,
                                                  &old_desc_blk,
                                                  &new_desc_blk, 0);
                        if (ext2fs_has_feature_meta_bg(fs->super))
                                old_desc_blocks = fs->super->s_first_meta_bg;
                        else
                                old_desc_blocks = fs->desc_blocks +
                                        fs->super->s_reserved_gdt_blocks;
                }
        }
        total_blocks_free = C2B(total_blocks_free);
        ext2fs_free_blocks_count_set(fs->super, total_blocks_free);

        /*
         * Next, calculate the inode statistics
         */
        group_free = 0;
        count = 0;
        group = 0;

        /* Protect loop from wrap-around if s_inodes_count maxed */
        uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT);
        for (ino = 1; ino <= fs->super->s_inodes_count && ino > 0; ino++) {
                if (uninit ||
                    !ext2fs_fast_test_inode_bitmap2(fs->inode_map, ino)) {
                        group_free++;
                        total_inodes_free++;
                }
                count++;
                if ((count == fs->super->s_inodes_per_group) ||
                    (ino == fs->super->s_inodes_count)) {
                        ext2fs_bg_free_inodes_count_set(fs, group, group_free);
                        ext2fs_group_desc_csum_set(fs, group);
                        group++;
                        if (group >= fs->group_desc_count)
                                break;
                        count = 0;
                        group_free = 0;
                        uninit = ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT);
                }
        }
        fs->super->s_free_inodes_count = total_inodes_free;
        ext2fs_mark_super_dirty(fs);
        return 0;
}

/*
 *  Journal may have been relocated; update the backup journal blocks
 *  in the superblock.
 */
static errcode_t fix_sb_journal_backup(ext2_filsys fs)
{
        errcode_t         retval;
        struct ext2_inode inode;

        if (!ext2fs_has_feature_journal(fs->super))
                return 0;

        /* External journal? Nothing to do. */
        if (fs->super->s_journal_dev && !fs->super->s_journal_inum)
                return 0;

        retval = ext2fs_read_inode(fs, fs->super->s_journal_inum, &inode);
        if (retval)
                return retval;
        memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
        fs->super->s_jnl_blocks[15] = inode.i_size_high;
        fs->super->s_jnl_blocks[16] = inode.i_size;
        fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
        ext2fs_mark_super_dirty(fs);
        return 0;
}

static int calc_group_overhead(ext2_filsys fs, blk64_t grp,
                               int old_desc_blocks)
{
        blk64_t super_blk, old_desc_blk, new_desc_blk;
        int overhead;

        /* inode table blocks plus allocation bitmaps */
        overhead = fs->inode_blocks_per_group + 2;

        ext2fs_super_and_bgd_loc2(fs, grp, &super_blk,
                                  &old_desc_blk, &new_desc_blk, 0);
        if ((grp == 0) || super_blk)
                overhead++;
        if (old_desc_blk)
                overhead += old_desc_blocks;
        else if (new_desc_blk)
                overhead++;
        return overhead;
}


/*
 * calculate the minimum number of blocks the given fs can be resized to
 */
blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
{
        ext2_ino_t inode_count;
        dgrp_t groups, flex_groups;
        blk64_t blks_needed, data_blocks;
        blk64_t grp, data_needed, last_start;
        blk64_t overhead = 0;
        int old_desc_blocks;
        int flexbg_size = 1 << fs->super->s_log_groups_per_flex;

        /*
         * first figure out how many group descriptors we need to
         * handle the number of inodes we have
         */
        inode_count = fs->super->s_inodes_count -
                fs->super->s_free_inodes_count;
        blks_needed = ext2fs_div_ceil(inode_count,
                                      fs->super->s_inodes_per_group) *
                (blk64_t) EXT2_BLOCKS_PER_GROUP(fs->super);
        groups = ext2fs_div64_ceil(blks_needed,
                                   EXT2_BLOCKS_PER_GROUP(fs->super));
#ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)
                printf("fs has %d inodes, %d groups required.\n",
                       inode_count, groups);
#endif

        /*
         * number of old-style block group descriptor blocks
         */
        if (ext2fs_has_feature_meta_bg(fs->super))
                old_desc_blocks = fs->super->s_first_meta_bg;
        else
                old_desc_blocks = fs->desc_blocks +
                        fs->super->s_reserved_gdt_blocks;

        /* calculate how many blocks are needed for data */
        data_needed = ext2fs_blocks_count(fs->super);
        for (grp = 0; grp < fs->group_desc_count; grp++) {
                data_needed -= calc_group_overhead(fs, grp, old_desc_blocks);
                data_needed -= ext2fs_bg_free_blocks_count(fs, grp);
        }
#ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)
                printf("fs requires %llu data blocks.\n",
                       (unsigned long long) data_needed);
#endif

        /*
         * For ext4 we need to allow for up to a flex_bg worth of
         * inode tables of slack space so the resize operation can be
         * guaranteed to finish.
         */
        flex_groups = groups;
        if (ext2fs_has_feature_flex_bg(fs->super)) {
                dgrp_t remainder = groups & (flexbg_size - 1);

                flex_groups += flexbg_size - remainder;
                if (flex_groups > fs->group_desc_count)
                        flex_groups = fs->group_desc_count;
        }

        /*
         * figure out how many data blocks we have given the number of groups
         * we need for our inodes
         */
        data_blocks = EXT2_GROUPS_TO_BLOCKS(fs->super, groups);
        last_start = 0;
        for (grp = 0; grp < flex_groups; grp++) {
                overhead = calc_group_overhead(fs, grp, old_desc_blocks);

                /*
                 * we want to keep track of how much data we can store in
                 * the groups leading up to the last group so we can determine
                 * how big the last group needs to be
                 */
                if (grp < (groups - 1))
                        last_start += EXT2_BLOCKS_PER_GROUP(fs->super) -
                                overhead;

                if (data_blocks > overhead)
                        data_blocks -= overhead;
                else
                        data_blocks = 0;
        }
#ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)
                printf("With %d group(s), we have %llu blocks available.\n",
                       groups, (unsigned long long) data_blocks);
#endif

        /*
         * if we need more group descriptors in order to accommodate our data
         * then we need to add them here
         */
        blks_needed = data_needed;
        while (blks_needed > data_blocks) {
                blk64_t remainder = blks_needed - data_blocks;
                dgrp_t extra_grps;

                /* figure out how many more groups we need for the data */
                extra_grps = ext2fs_div64_ceil(remainder,
                                               EXT2_BLOCKS_PER_GROUP(fs->super));

                data_blocks += EXT2_GROUPS_TO_BLOCKS(fs->super, extra_grps);

                /* ok we have to account for the last group */
                overhead = calc_group_overhead(fs, groups-1, old_desc_blocks);
                last_start += EXT2_BLOCKS_PER_GROUP(fs->super) - overhead;

                grp = flex_groups;
                groups += extra_grps;
                if (!ext2fs_has_feature_flex_bg(fs->super))
                        flex_groups = groups;
                else if (groups > flex_groups) {
                        dgrp_t r = groups & (flexbg_size - 1);

                        flex_groups = groups + flexbg_size - r;
                        if (flex_groups > fs->group_desc_count)
                                flex_groups = fs->group_desc_count;
                }

                for (; grp < flex_groups; grp++) {
                        overhead = calc_group_overhead(fs, grp,
                                                       old_desc_blocks);

                        /*
                         * again, we need to see how much data we cram into
                         * all of the groups leading up to the last group
                         */
                        if (grp < groups - 1)
                                last_start += EXT2_BLOCKS_PER_GROUP(fs->super)
                                        - overhead;

                        data_blocks -= overhead;
                }

#ifdef RESIZE2FS_DEBUG
                if (flags & RESIZE_DEBUG_MIN_CALC)
                        printf("Added %d extra group(s), "
                               "blks_needed %llu, data_blocks %llu, "
                               "last_start %llu\n", extra_grps,
                               (unsigned long long) blks_needed,
                               (unsigned long long) data_blocks,
                               (unsigned long long) last_start);
#endif
        }

        /* now for the fun voodoo */
        grp = groups - 1;
        if (ext2fs_has_feature_flex_bg(fs->super) &&
            (grp & ~(flexbg_size - 1)) == 0)
                grp = grp & ~(flexbg_size - 1);
        overhead = 0;
        for (; grp < flex_groups; grp++)
                overhead += calc_group_overhead(fs, grp, old_desc_blocks);

#ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)
                printf("Last group's overhead is %llu\n",
                       (unsigned long long) overhead);
#endif

        /*
         * if this is the case then the last group is going to have data in it
         * so we need to adjust the size of the last group accordingly
         */
        if (last_start < blks_needed) {
                blk64_t remainder = blks_needed - last_start;

#ifdef RESIZE2FS_DEBUG
                if (flags & RESIZE_DEBUG_MIN_CALC)
                        printf("Need %llu data blocks in last group\n",
                               (unsigned long long) remainder);
#endif
                /*
                 * 50 is a magic number that mkfs/resize uses to see if its
                 * even worth making/resizing the fs.  basically you need to
                 * have at least 50 blocks in addition to the blocks needed
                 * for the metadata in the last group
                 */
                if (remainder > 50)
                        overhead += remainder;
                else
                        overhead += 50;
        } else
                overhead += 50;

        overhead += fs->super->s_first_data_block;
#ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)
                printf("Final size of last group is %llu\n",
                       (unsigned long long) overhead);
#endif

        /* Add extra slack for bigalloc file systems */
        if (EXT2FS_CLUSTER_RATIO(fs) > 1)
                overhead += EXT2FS_CLUSTER_RATIO(fs) * 2;

        /*
         * since our last group doesn't have to be BLOCKS_PER_GROUP
         * large, we only do groups-1, and then add the number of
         * blocks needed to handle the group descriptor metadata+data
         * that we need
         */
        blks_needed = EXT2_GROUPS_TO_BLOCKS(fs->super, groups - 1);
        blks_needed += overhead;

        /*
         * Make sure blks_needed covers the end of the inode table in
         * the last block group.
         */
        overhead = ext2fs_inode_table_loc(fs, groups-1) +
                fs->inode_blocks_per_group;
        if (blks_needed < overhead)
                blks_needed = overhead;

#ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)
                printf("Estimated blocks needed: %llu\n",
                       (unsigned long long) blks_needed);
#endif

        /*
         * If at this point we've already added up more "needed" than
         * the current size, just return current size as minimum.
         */
        if (blks_needed >= ext2fs_blocks_count(fs->super))
                return ext2fs_blocks_count(fs->super);
        /*
         * We need to reserve a few extra blocks if extents are
         * enabled, in case we need to grow the extent tree.  The more
         * we shrink the file system, the more space we need.
         *
         * The absolute worst case is every single data block is in
         * the part of the file system that needs to be evacuated,
         * with each data block needs to be in its own extent, and
         * with each inode needing at least one extent block.
         */
        if (ext2fs_has_feature_extents(fs->super)) {
                blk64_t safe_margin = (ext2fs_blocks_count(fs->super) -
                                       blks_needed)/500;
                unsigned int exts_per_blk = (fs->blocksize /
                                             sizeof(struct ext3_extent)) - 1;
                blk64_t worst_case = ((data_needed + exts_per_blk - 1) /
                                      exts_per_blk);

                if (worst_case < inode_count)
                        worst_case = inode_count;

                if (safe_margin > worst_case)
                        safe_margin = worst_case;

#ifdef RESIZE2FS_DEBUG
                if (flags & RESIZE_DEBUG_MIN_CALC)
                        printf("Extents safety margin: %llu\n",
                               (unsigned long long) safe_margin);
#endif
                blks_needed += safe_margin;
        }

        return blks_needed;
}