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e2fsprogs/resize/resize2fs.c

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/*
* resize2fs.c --- ext2 main routine
*
* Copyright (C) 1997 Theodore Ts'o
*
* %Begin-Header%
* All rights reserved.
* %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.
* 3. (*) Relocate blocks which must be moved, adjusting entries
* in the filesystem in the process.
* 4. (*) Move inodes which must be moved (only when shrinking a
* filesystem)
* 5. (*) Move the inode tables, if necessary.
*/
#include "resize2fs.h"
/*
* This routine adjusts the superblock and other data structures...
*/
static errcode_t adjust_superblock(ext2_resize_t rfs, blk_t new_size)
{
ext2_filsys fs;
int overhead = 0;
int rem, adj = 0;
errcode_t retval;
ino_t real_end;
blk_t blk, group_block;
unsigned long i, j;
struct ext2_group_desc *new;
int old_numblocks, numblocks, adjblocks;
ext2_sim_progmeter progress = 0;
fs = rfs->new_fs;
fs->super->s_blocks_count = new_size;
ext2fs_mark_super_dirty(fs);
ext2fs_mark_bb_dirty(fs);
ext2fs_mark_ib_dirty(fs);
retry:
fs->group_desc_count = (fs->super->s_blocks_count -
fs->super->s_first_data_block +
EXT2_BLOCKS_PER_GROUP(fs->super) - 1)
/ EXT2_BLOCKS_PER_GROUP(fs->super);
if (fs->group_desc_count == 0)
return EXT2_ET_TOOSMALL;
fs->desc_blocks = (fs->group_desc_count +
EXT2_DESC_PER_BLOCK(fs->super) - 1)
/ EXT2_DESC_PER_BLOCK(fs->super);
/*
* Overhead is the number of bookkeeping blocks per group. It
* includes the superblock backup, the group descriptor
* backups, the inode bitmap, the block bitmap, and the inode
* table.
*
* XXX Not all block groups need the descriptor blocks, but
* being clever is tricky...
*/
overhead = 3 + fs->desc_blocks + fs->inode_blocks_per_group;
/*
* See if the last group is big enough to support the
* necessary data structures. If not, we need to get rid of
* it.
*/
rem = (fs->super->s_blocks_count - fs->super->s_first_data_block) %
fs->super->s_blocks_per_group;
if ((fs->group_desc_count == 1) && rem && (rem < overhead))
return EXT2_ET_TOOSMALL;
if (rem && (rem < overhead+50)) {
fs->super->s_blocks_count -= rem;
goto retry;
}
/*
* Adjust the number of inodes
*/
fs->super->s_inodes_count = fs->super->s_inodes_per_group *
fs->group_desc_count;
/*
* Adjust the number of free blocks
*/
blk = rfs->old_fs->super->s_blocks_count;
if (blk > fs->super->s_blocks_count)
fs->super->s_free_blocks_count -=
(blk - fs->super->s_blocks_count);
else
fs->super->s_free_blocks_count +=
(fs->super->s_blocks_count - blk);
/*
* Adjust the number of reserved blocks
*/
blk = rfs->old_fs->super->s_r_blocks_count * 100 /
rfs->old_fs->super->s_blocks_count;
fs->super->s_r_blocks_count = ((fs->super->s_blocks_count * blk)
/ 100);
/*
* Adjust the bitmaps for size
*/
retval = ext2fs_resize_inode_bitmap(fs->super->s_inodes_count,
fs->super->s_inodes_count,
fs->inode_map);
if (retval) goto errout;
real_end = ((EXT2_BLOCKS_PER_GROUP(fs->super)
* fs->group_desc_count)) - 1 +
fs->super->s_first_data_block;
retval = ext2fs_resize_block_bitmap(fs->super->s_blocks_count-1,
real_end, fs->block_map);
if (retval) goto errout;
/*
* Reallocate the group descriptors as necessary.
*/
if (rfs->old_fs->desc_blocks != fs->desc_blocks) {
new = realloc(fs->group_desc,
fs->desc_blocks * fs->blocksize);
if (!new)
return ENOMEM;
fs->group_desc = new;
}
/*
* Fix the count of the last (old) block group
*/
if (rfs->old_fs->group_desc_count > fs->group_desc_count) {
retval = 0;
goto errout;
}
old_numblocks = (rfs->old_fs->super->s_blocks_count -
rfs->old_fs->super->s_first_data_block) %
rfs->old_fs->super->s_blocks_per_group;
if (!old_numblocks)
old_numblocks = rfs->old_fs->super->s_blocks_per_group;
if (rfs->old_fs->group_desc_count == fs->group_desc_count) {
numblocks = (rfs->new_fs->super->s_blocks_count -
rfs->new_fs->super->s_first_data_block) %
rfs->new_fs->super->s_blocks_per_group;
if (!numblocks)
numblocks = rfs->new_fs->super->s_blocks_per_group;
} else
numblocks = rfs->new_fs->super->s_blocks_per_group;
i = rfs->old_fs->group_desc_count - 1;
fs->group_desc[i].bg_free_blocks_count += (numblocks-old_numblocks);
/*
* Initialize the new block group descriptors
*/
if (rfs->old_fs->group_desc_count >= fs->group_desc_count) {
retval = 0;
goto errout;
}
rfs->itable_buf = malloc(fs->blocksize * fs->inode_blocks_per_group);
if (!rfs->itable_buf) {
retval = ENOMEM;
goto errout;
}
memset(rfs->itable_buf, 0, fs->blocksize * fs->inode_blocks_per_group);
group_block = fs->super->s_first_data_block +
rfs->old_fs->group_desc_count * fs->super->s_blocks_per_group;
if (rfs->flags & RESIZE_PERCENT_COMPLETE) {
adj = rfs->old_fs->group_desc_count;
retval = ext2fs_progress_init(&progress,
"Initializing inode table", 30, 40,
fs->group_desc_count - adj, 0);
if (retval) goto errout;
}
for (i = rfs->old_fs->group_desc_count;
i < fs->group_desc_count; i++) {
memset(&fs->group_desc[i], 0,
sizeof(struct ext2_group_desc));
adjblocks = 0;
if (i == fs->group_desc_count-1) {
numblocks = (fs->super->s_blocks_count -
fs->super->s_first_data_block) %
fs->super->s_blocks_per_group;
if (!numblocks)
numblocks = fs->super->s_blocks_per_group;
} else
numblocks = fs->super->s_blocks_per_group;
if (ext2fs_bg_has_super(fs, i)) {
for (j=0; j < fs->desc_blocks+1; j++)
ext2fs_mark_block_bitmap(fs->block_map,
group_block + j);
adjblocks = 1 + fs->desc_blocks;
}
adjblocks += 2 + fs->inode_blocks_per_group;
numblocks -= adjblocks;
fs->super->s_free_blocks_count -= adjblocks;
fs->super->s_free_inodes_count +=
fs->super->s_inodes_per_group;
fs->group_desc[i].bg_free_blocks_count = numblocks;
fs->group_desc[i].bg_free_inodes_count =
fs->super->s_inodes_per_group;
fs->group_desc[i].bg_used_dirs_count = 0;
retval = ext2fs_allocate_group_table(fs, i, 0);
if (retval) goto errout;
/*
* Write out the new inode table
*/
retval = io_channel_write_blk(fs->io,
fs->group_desc[i].bg_inode_table,
fs->inode_blocks_per_group,
rfs->itable_buf);
if (retval) goto errout;
/* io_channel_flush(fs->io); */
if (progress)
ext2fs_progress_update(progress, i - adj + 1);
group_block += fs->super->s_blocks_per_group;
}
io_channel_flush(fs->io);
retval = 0;
errout:
if (progress)
ext2fs_progress_close(progress);
return retval;
}
/*
* 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 *ret_bmap)
{
blk_t block, b;
int i,j;
ext2fs_block_bitmap bmap;
errcode_t retval;
retval = ext2fs_allocate_block_bitmap(fs, "meta-data blocks", &bmap);
if (retval)
return retval;
block = fs->super->s_first_data_block;
for (i = 0; i < fs->group_desc_count; i++) {
if (ext2fs_bg_has_super(fs, i)) {
/*
* Mark this group's copy of the superblock
*/
ext2fs_mark_block_bitmap(bmap, block);
/*
* Mark this group's copy of the descriptors
*/
for (j = 0; j < fs->desc_blocks; j++)
ext2fs_mark_block_bitmap(bmap, block + j + 1);
}
/*
* Mark the blocks used for the inode table
*/
for (j = 0, b = fs->group_desc[i].bg_inode_table;
j < fs->inode_blocks_per_group;
j++, b++)
ext2fs_mark_block_bitmap(bmap, b);
/*
* Mark block used for the block bitmap
*/
ext2fs_mark_block_bitmap(bmap,
fs->group_desc[i].bg_block_bitmap);
/*
* Mark block used for the inode bitmap
*/
ext2fs_mark_block_bitmap(bmap,
fs->group_desc[i].bg_inode_bitmap);
block += fs->super->s_blocks_per_group;
}
*ret_bmap = bmap;
return 0;
}
/*
* Some helper CPP macros
*/
#define FS_BLOCK_BM(fs, i) ((fs)->group_desc[(i)].bg_block_bitmap)
#define FS_INODE_BM(fs, i) ((fs)->group_desc[(i)].bg_inode_bitmap)
#define FS_INODE_TB(fs, i) ((fs)->group_desc[(i)].bg_inode_table)
#define IS_BLOCK_BM(fs, i, blk) ((blk) == FS_BLOCK_BM((fs),(i)))
#define IS_INODE_BM(fs, i, blk) ((blk) == FS_INODE_BM((fs),(i)))
#define IS_INODE_TB(fs, i, blk) (((blk) >= FS_INODE_TB((fs), (i))) && \
((blk) < (FS_INODE_TB((fs), (i)) + \
(fs)->inode_blocks_per_group)))
/*
* 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)
{
int i, j, max;
blk_t blk, group_blk;
unsigned long old_blocks, new_blocks;
errcode_t retval;
ext2_filsys fs, old_fs;
ext2fs_block_bitmap meta_bmap;
fs = rfs->new_fs;
old_fs = rfs->old_fs;
if (old_fs->super->s_blocks_count > fs->super->s_blocks_count)
fs = rfs->old_fs;
retval = ext2fs_allocate_block_bitmap(fs, "reserved blocks",
&rfs->reserve_blocks);
if (retval)
return retval;
retval = ext2fs_allocate_block_bitmap(fs, "blocks to be moved",
&rfs->move_blocks);
if (retval)
return retval;
retval = mark_table_blocks(fs, &meta_bmap);
if (retval)
return retval;
fs = rfs->new_fs;
/*
* If we're shrinking the filesystem, we need to move all of
* the blocks that don't fit any more
*/
for (blk = fs->super->s_blocks_count;
blk < old_fs->super->s_blocks_count; blk++) {
if (ext2fs_test_block_bitmap(old_fs->block_map, blk) &&
!ext2fs_test_block_bitmap(meta_bmap, blk)) {
ext2fs_mark_block_bitmap(rfs->move_blocks, blk);
rfs->needed_blocks++;
}
ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
}
old_blocks = old_fs->desc_blocks;
new_blocks = fs->desc_blocks;
if (old_blocks == new_blocks) {
retval = 0;
goto errout;
}
max = fs->group_desc_count;
if (max > old_fs->group_desc_count)
max = 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) {
for (i = 0; i < max; i++) {
if (!ext2fs_bg_has_super(fs, i)) {
group_blk += fs->super->s_blocks_per_group;
continue;
}
for (blk = group_blk+1+new_blocks;
blk < group_blk+1+old_blocks; blk++) {
ext2fs_unmark_block_bitmap(fs->block_map,
blk);
rfs->needed_blocks--;
}
group_blk += fs->super->s_blocks_per_group;
}
retval = 0;
goto errout;
}
/*
* If we're increasing the number of descriptor blocks, life
* gets interesting....
*/
for (i = 0; i < max; i++) {
if (!ext2fs_bg_has_super(fs, i))
goto next_group;
for (blk = group_blk;
blk < group_blk + 1 + new_blocks; blk++) {
ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
ext2fs_mark_block_bitmap(fs->block_map, blk);
/*
* Check to see if we overlap with the inode
* or block bitmap, 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, i, blk)) {
FS_BLOCK_BM(fs, i) = 0;
rfs->needed_blocks++;
} else if (IS_INODE_BM(fs, i, blk)) {
FS_INODE_BM(fs, i) = 0;
rfs->needed_blocks++;
} else if (IS_INODE_TB(fs, i, blk)) {
FS_INODE_TB(fs, i) = 0;
rfs->needed_blocks++;
} else if (ext2fs_test_block_bitmap(old_fs->block_map,
blk) &&
!ext2fs_test_block_bitmap(meta_bmap, blk)) {
ext2fs_mark_block_bitmap(rfs->move_blocks,
blk);
rfs->needed_blocks++;
}
}
if (fs->group_desc[i].bg_inode_table &&
fs->group_desc[i].bg_inode_bitmap &&
fs->group_desc[i].bg_block_bitmap)
goto next_group;
/*
* Reserve the existing meta blocks that we know
* aren't to be moved.
*/
if (fs->group_desc[i].bg_block_bitmap)
ext2fs_mark_block_bitmap(rfs->reserve_blocks,
fs->group_desc[i].bg_block_bitmap);
if (fs->group_desc[i].bg_inode_bitmap)
ext2fs_mark_block_bitmap(rfs->reserve_blocks,
fs->group_desc[i].bg_inode_bitmap);
if (fs->group_desc[i].bg_inode_table)
for (blk = fs->group_desc[i].bg_inode_table, j=0;
j < fs->inode_blocks_per_group ; j++, blk++)
ext2fs_mark_block_bitmap(rfs->reserve_blocks,
blk);
/*
* Allocate the missing data structures
*/
retval = ext2fs_allocate_group_table(fs, i,
rfs->reserve_blocks);
if (retval)
goto errout;
/*
* For those structures that have changed, we need to
* do bookkeepping.
*/
if (FS_BLOCK_BM(old_fs, i) !=
(blk = FS_BLOCK_BM(fs, i))) {
ext2fs_mark_block_bitmap(fs->block_map, blk);
if (ext2fs_test_block_bitmap(old_fs->block_map, blk) &&
!ext2fs_test_block_bitmap(meta_bmap, blk))
ext2fs_mark_block_bitmap(rfs->move_blocks,
blk);
}
if (FS_INODE_BM(old_fs, i) !=
(blk = FS_INODE_BM(fs, i))) {
ext2fs_mark_block_bitmap(fs->block_map, blk);
if (ext2fs_test_block_bitmap(old_fs->block_map, blk) &&
!ext2fs_test_block_bitmap(meta_bmap, blk))
ext2fs_mark_block_bitmap(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 (FS_INODE_TB(fs, i) == FS_INODE_TB(old_fs, i))
goto next_group; /* 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 = fs->group_desc[i].bg_inode_table, j=0;
j < fs->inode_blocks_per_group ; j++, blk++) {
ext2fs_mark_block_bitmap(fs->block_map, blk);
if (ext2fs_test_block_bitmap(old_fs->block_map, blk) &&
!ext2fs_test_block_bitmap(meta_bmap, blk))
ext2fs_mark_block_bitmap(rfs->move_blocks,
blk);
}
/*
* Make sure the old inode table is reserved in the
* block reservation bitmap.
*/
for (blk = rfs->old_fs->group_desc[i].bg_inode_table, j=0;
j < fs->inode_blocks_per_group ; j++, blk++)
ext2fs_mark_block_bitmap(rfs->reserve_blocks, blk);
next_group:
group_blk += rfs->new_fs->super->s_blocks_per_group;
}
retval = 0;
errout:
if (meta_bmap)
ext2fs_free_block_bitmap(meta_bmap);
return retval;
}
/*
* 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 i, n, num, max, size, diff;
ext2_filsys fs = rfs->new_fs;
char *cp;
blk_t old, new;
errcode_t retval, err;
ext2_sim_progmeter progress = 0;
int to_move, moved;
max = fs->group_desc_count;
if (max > rfs->old_fs->group_desc_count)
max = rfs->old_fs->group_desc_count;
size = fs->blocksize * fs->inode_blocks_per_group;
if (!rfs->itable_buf) {
rfs->itable_buf = malloc(size);
if (!rfs->itable_buf)
return ENOMEM;
}
/*
* Figure out how many inode tables we need to move
*/
to_move = moved = 0;
for (i=0; i < max; i++)
if (rfs->old_fs->group_desc[i].bg_inode_table !=
fs->group_desc[i].bg_inode_table)
to_move++;
if (to_move == 0)
return 0;
if (rfs->flags & RESIZE_PERCENT_COMPLETE) {
retval = ext2fs_progress_init(&progress,
"Moving inode table", 30, 40, to_move, 0);
if (retval)
return retval;
}
for (i=0; i < max; i++) {
old = rfs->old_fs->group_desc[i].bg_inode_table;
new = fs->group_desc[i].bg_inode_table;
diff = new - old;
if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
printf("Itable move group %d block "
"%u->%u (diff %d)\n",
i, old, new, diff);
if (!diff)
continue;
retval = io_channel_read_blk(fs->io, old,
fs->inode_blocks_per_group,
rfs->itable_buf);
if (retval)
goto backout;
/*
* The end of the inode table segment often contains
* all zeros. Find out if we have several blocks of
* zeros so we can optimize the write.
*/
for (cp = rfs->itable_buf+size, n=0; n < size; n++, cp--)
if (*cp)
break;
n = n >> EXT2_BLOCK_SIZE_BITS(fs->super);
if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
printf("%d blocks of zeros...\n", n);
num = fs->inode_blocks_per_group;
if (n > diff)
num -= n;
retval = io_channel_write_blk(fs->io, new,
num, rfs->itable_buf);
if (retval) {
io_channel_write_blk(fs->io, old,
num, rfs->itable_buf);
goto backout;
}
if (n > diff) {
retval = io_channel_write_blk(fs->io,
old + fs->inode_blocks_per_group,
diff, rfs->itable_buf - fs->blocksize * diff);
if (retval)
goto backout;
}
io_channel_flush(fs->io);
if (progress)
ext2fs_progress_update(progress, ++moved);
}
ext2fs_flush(rfs->new_fs);
io_channel_flush(fs->io);
if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
printf("Inode table move finished.\n");
if (progress)
ext2fs_progress_close(progress);
return 0;
backout:
if (progress)
ext2fs_progress_close(progress);
if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
printf("Error: %s; now backing out!\n", error_message(retval));
while (--i >= 0) {
if (rfs->flags & RESIZE_DEBUG_ITABLEMOVE)
printf("Group %d block %u->%u\n", i, new, old);
old = rfs->old_fs->group_desc[i].bg_inode_table;
new = fs->group_desc[i].bg_inode_table;
err = io_channel_read_blk(fs->io, new,
fs->inode_blocks_per_group,
rfs->itable_buf);
if (err)
continue;
err = io_channel_write_blk(fs->io, old,
fs->inode_blocks_per_group,
rfs->itable_buf);
}
return retval;
}
/*
* Finally, recalculate the summary information
*/
static errcode_t ext2fs_calculate_summary_stats(ext2_filsys fs)
{
blk_t blk;
ino_t ino;
int group = 0;
int count = 0;
int total_free = 0;
int group_free = 0;
/*
* First calculate the block statistics
*/
for (blk = fs->super->s_first_data_block;
blk < fs->super->s_blocks_count; blk++) {
if (!ext2fs_fast_test_block_bitmap(fs->block_map, blk)) {
group_free++;
total_free++;
}
count++;
if ((count == fs->super->s_blocks_per_group) ||
(blk == fs->super->s_blocks_count-1)) {
fs->group_desc[group++].bg_free_blocks_count =
group_free;
count = 0;
group_free = 0;
}
}
fs->super->s_free_blocks_count = total_free;
/*
* Next, calculate the inode statistics
*/
group_free = 0;
total_free = 0;
count = 0;
group = 0;
for (ino = 1; ino <= fs->super->s_inodes_count; ino++) {
if (!ext2fs_fast_test_inode_bitmap(fs->inode_map, ino)) {
group_free++;
total_free++;
}
count++;
if ((count == fs->super->s_inodes_per_group) ||
(ino == fs->super->s_inodes_count)) {
fs->group_desc[group++].bg_free_inodes_count =
group_free;
count = 0;
group_free = 0;
}
}
fs->super->s_free_inodes_count = total_free;
ext2fs_mark_super_dirty(fs);
return 0;
}
/*
* This is the top-level routine which does the dirty deed....
*/
errcode_t resize_fs(ext2_filsys fs, blk_t new_size, int flags)
{
ext2_resize_t rfs;
errcode_t retval;
retval = ext2fs_read_bitmaps(fs);
if (retval)
return retval;
/*
* Create the data structure
*/
rfs = malloc(sizeof(struct ext2_resize_struct));
if (!rfs)
return ENOMEM;
memset(rfs, 0, sizeof(struct ext2_resize_struct));
rfs->old_fs = fs;
rfs->flags = flags;
rfs->itable_buf = 0;
retval = ext2fs_dup_handle(fs, &rfs->new_fs);
if (retval)
goto errout;
retval = adjust_superblock(rfs, new_size);
if (retval)
goto errout;
retval = blocks_to_move(rfs);
if (retval)
goto errout;
if (rfs->flags & RESIZE_DEBUG_BMOVE)
printf("Number of free blocks: %d/%d, Needed: %d\n",
rfs->old_fs->super->s_free_blocks_count,
rfs->new_fs->super->s_free_blocks_count,
rfs->needed_blocks);
retval = ext2fs_block_move(rfs);
if (retval)
goto errout;
retval = ext2fs_inode_move(rfs);
if (retval)
goto errout;
retval = move_itables(rfs);
if (retval)
goto errout;
retval = ext2fs_calculate_summary_stats(rfs->new_fs);
if (retval)
goto errout;
retval = ext2fs_close(rfs->new_fs);
if (retval)
goto errout;
rfs->flags = flags;
ext2fs_free(rfs->old_fs);
if (rfs->itable_buf)
free(rfs->itable_buf);
free(rfs);
return 0;
errout:
if (rfs->new_fs)
ext2fs_free(rfs->new_fs);
if (rfs->itable_buf)
free(rfs->itable_buf);
free(rfs);
return retval;
}
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