ext4-realloc-inodes/bmove.c

/*
 * bmove.c --- Move blocks around to make way for a particular filesystem structure.
 * Adjusted to work correctly with bigalloc.
 *
 * Copyright (C) 1997 Theodore Ts'o, (C) 2014 Vitaliy Filippov.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Library
 * General Public License, version 2.
 * %End-Header%
 */

#include <stdio.h>
#include <string.h>

#include "bmove.h"

struct process_block_struct {
	ext2_ino_t ino;
	struct ext2_inode *inode;
	ext2fs_block_bitmap reserve;
	ext2fs_block_bitmap alloc_map;
	errcode_t error;
	char *buf;
	int add_dir;
	int flags;
	int changes;
	blk64_t last, last_new;
};

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

	pb = (struct process_block_struct *) priv_data;
	block = orig = *block_nr;
	ret = 0;

	/*
	 * Let's see if this is one which we need to relocate
	 */
	if (ext2fs_test_block_bitmap2(pb->reserve, block)) {
		if (block & EXT2FS_CLUSTER_MASK(fs)) {
			// This means we've already moved the cluster and just need
			// to rewrite numbers of a non-first block in a cluster
			if (pb->last == block-1) {
				*block_nr = pb->last_new+1;
				pb->last++;
				pb->changes++;
				return BLOCK_CHANGED;
			}
			return 0;
		}
		if (blockcnt >= 0 && (pb->ino == EXT2_BAD_INO || pb->ino == EXT2_RESIZE_INO)) {
			// We obviously can't move bad blocks; and also the resize inode, because it must be in a predefined location
			// But we allow to move extent blocks (blockcnt == -1) and directory index blocks (blockcnt == -2)
			pb->error = EXT2_ET_BAD_BLOCK_IN_INODE_TABLE;
			return BLOCK_ABORT;
		}
		do {
			if (++block >= ext2fs_blocks_count(fs->super))
				block = fs->super->s_first_data_block;
			if (block == orig) {
				pb->error = EXT2_ET_BLOCK_ALLOC_FAIL;
				return BLOCK_ABORT;
			}
		} while (ext2fs_test_block_bitmap2(pb->reserve, block) ||
			ext2fs_test_block_bitmap2(pb->alloc_map, block));

		retval = io_channel_read_blk64(fs->io, orig, EXT2FS_CLUSTER_RATIO(fs), pb->buf);
		if (retval) {
			pb->error = retval;
			return BLOCK_ABORT;
		}
		retval = io_channel_write_blk64(fs->io, block, EXT2FS_CLUSTER_RATIO(fs), pb->buf);
		if (retval) {
			pb->error = retval;
			return BLOCK_ABORT;
		}
		*block_nr = block;
		pb->last = orig;
		pb->last_new = block;
		ext2fs_block_alloc_stats2(fs, orig, -1);
		ext2fs_block_alloc_stats2(fs, block, +1);
		ret = BLOCK_CHANGED;
		pb->changes++;
		if (pb->flags & EXT2_BMOVE_DEBUG)
			printf("ino=%u, blockcnt=%lld, %llu->%llu\n",
			       (unsigned) pb->ino, blockcnt,
			       (unsigned long long) orig,
			       (unsigned long long) block);
	}
	if (pb->add_dir) {
		retval = ext2fs_add_dir_block2(fs->dblist, pb->ino, block, blockcnt);
		if (retval) {
			pb->error = retval;
			ret |= BLOCK_ABORT;
		}
	}
	return ret;
}

errcode_t ext2fs_move_blocks(ext2_filsys fs,
			     ext2fs_block_bitmap reserve,
			     ext2fs_block_bitmap alloc_map,
			     int flags)
{
	ext2_ino_t ino;
	struct ext2_inode inode;
	errcode_t retval;
	struct process_block_struct pb;
	ext2_inode_scan scan;
	char *block_buf;

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

	pb.reserve = reserve;
	pb.error = 0;
	pb.alloc_map = alloc_map ? alloc_map : fs->block_map;
	pb.flags = flags;

	retval = ext2fs_get_array(3 + EXT2FS_CLUSTER_RATIO(fs), fs->blocksize, &block_buf);
	if (retval)
		return retval;
	pb.buf = block_buf + fs->blocksize * 3;
	pb.last = -1;
	pb.changes = 0;

	/*
	 * If GET_DBLIST is set in the flags field, then we should
	 * gather directory block information while we're doing the
	 * block move.
	 */
	if (flags & EXT2_BMOVE_GET_DBLIST) {
		if (fs->dblist) {
			ext2fs_free_dblist(fs->dblist);
			fs->dblist = NULL;
		}
		retval = ext2fs_init_dblist(fs, 0);
		if (retval)
			return retval;
	}

	retval = ext2fs_get_next_inode(scan, &ino, &inode);
	if (retval)
		return retval;

	while (ino) {
		if ((inode.i_links_count == 0) || !ext2fs_inode_has_valid_blocks2(fs, &inode))
			goto next;

		pb.ino = ino;
		pb.inode = &inode;

		pb.add_dir = (LINUX_S_ISDIR(inode.i_mode) && flags & EXT2_BMOVE_GET_DBLIST);

		if ((inode.i_flags & EXT4_INLINE_DATA_FL) && pb.add_dir) {
			/* inline data dir; update it too */
			retval = ext2fs_add_dir_block2(fs->dblist, ino, 0, 0);
			if (retval)
				return retval;
		}

		retval = ext2fs_block_iterate3(fs, ino, 0, block_buf, process_block, &pb);
		if (retval)
			return retval;
		if (pb.error)
			return pb.error;

		// Adjust journal backup after changing the journal inode
		if (ino == EXT2_JOURNAL_INO && pb.changes) {
			retval = ext2fs_read_inode(fs, ino, &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);
		}

	next:
		retval = ext2fs_get_next_inode(scan, &ino, &inode);
		if (retval == EXT2_ET_BAD_BLOCK_IN_INODE_TABLE)
			goto next;
	}
	return 0;
}