Adding upstream version 1.47.0.upstream/1.47.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 590 insertions, 0 deletions

diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
new file mode 100644
index 0000000..fd56a9a
--- /dev/null
+++ b/lib/ext2fs/openfs.c
@@ -0,0 +1,590 @@
+/*
+ * openfs.c --- open an ext2 filesystem
+ *
+ * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
+ * %End-Header%
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <fcntl.h>
+#include <time.h>
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+
+#include "ext2_fs.h"
+
+#include "ext2fs.h"
+#include "e2image.h"
+
+blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block,
+				     dgrp_t i)
+{
+	int	bg;
+	int	has_super = 0, group_zero_adjust = 0;
+	blk64_t	ret_blk;
+
+	/*
+	 * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4
+	 * stuff, so adjust for that if we're being asked for group 0.
+	 */
+	if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1)
+		group_zero_adjust = 1;
+
+	if (!ext2fs_has_feature_meta_bg(fs->super) ||
+	    (i < fs->super->s_first_meta_bg))
+		return group_block + i + 1 + group_zero_adjust;
+
+	bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
+	if (ext2fs_bg_has_super(fs, bg))
+		has_super = 1;
+	ret_blk = ext2fs_group_first_block2(fs, bg);
+	/*
+	 * If group_block is not the normal value, we're trying to use
+	 * the backup group descriptors and superblock --- so use the
+	 * alternate location of the second block group in the
+	 * metablock group.  Ideally we should be testing each bg
+	 * descriptor block individually for correctness, but we don't
+	 * have the infrastructure in place to do that.
+	 */
+	if (group_block != fs->super->s_first_data_block &&
+	    ((ret_blk + has_super + fs->super->s_blocks_per_group) <
+	     ext2fs_blocks_count(fs->super))) {
+		ret_blk += fs->super->s_blocks_per_group;
+
+		/*
+		 * If we're going to jump forward a block group, make sure
+		 * that we adjust has_super to account for the next group's
+		 * backup superblock (or lack thereof).
+		 */
+		if (ext2fs_bg_has_super(fs, bg + 1))
+			has_super = 1;
+		else
+			has_super = 0;
+	}
+	return ret_blk + has_super + group_zero_adjust;
+}
+
+blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
+{
+	return ext2fs_descriptor_block_loc2(fs, group_block, i);
+}
+
+errcode_t ext2fs_open(const char *name, int flags, int superblock,
+		      unsigned int block_size, io_manager manager,
+		      ext2_filsys *ret_fs)
+{
+	return ext2fs_open2(name, 0, flags, superblock, block_size,
+			    manager, ret_fs);
+}
+
+static void block_sha_map_free_entry(void *data)
+{
+	free(data);
+	return;
+}
+
+/*
+ *  Note: if superblock is non-zero, block-size must also be non-zero.
+ * 	Superblock and block_size can be zero to use the default size.
+ *
+ * Valid flags for ext2fs_open()
+ *
+ * 	EXT2_FLAG_RW	- Open the filesystem for read/write.
+ * 	EXT2_FLAG_FORCE - Open the filesystem even if some of the
+ *				features aren't supported.
+ *	EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
+ *	EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
+ *	EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
+ *				filesystems)
+ */
+errcode_t ext2fs_open2(const char *name, const char *io_options,
+		       int flags, int superblock,
+		       unsigned int block_size, io_manager manager,
+		       ext2_filsys *ret_fs)
+{
+	ext2_filsys	fs;
+	errcode_t	retval;
+	unsigned long	i, first_meta_bg;
+	__u32		features;
+	unsigned int	blocks_per_group, io_flags;
+	blk64_t		group_block, blk;
+	char		*dest, *cp;
+	int		group_zero_adjust = 0;
+	unsigned int	inode_size;
+	__u64		groups_cnt;
+#ifdef WORDS_BIGENDIAN
+	unsigned int	groups_per_block;
+	struct ext2_group_desc *gdp;
+	int		j;
+#endif
+	char		*time_env;
+	int		csum_retries = 0;
+
+	EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
+
+	retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
+	if (retval)
+		return retval;
+
+	memset(fs, 0, sizeof(struct struct_ext2_filsys));
+	fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
+	fs->flags = flags;
+	/* don't overwrite sb backups unless flag is explicitly cleared */
+	fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
+	fs->umask = 022;
+
+	time_env = getenv("E2FSPROGS_FAKE_TIME");
+	if (time_env)
+		fs->now = strtoul(time_env, NULL, 0);
+
+	retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
+	if (retval)
+		goto cleanup;
+	strcpy(fs->device_name, name);
+	cp = strchr(fs->device_name, '?');
+	if (!io_options && cp) {
+		*cp++ = 0;
+		io_options = cp;
+	}
+
+	io_flags = 0;
+	if (flags & EXT2_FLAG_RW)
+		io_flags |= IO_FLAG_RW;
+	if (flags & EXT2_FLAG_EXCLUSIVE)
+		io_flags |= IO_FLAG_EXCLUSIVE;
+	if (flags & EXT2_FLAG_DIRECT_IO)
+		io_flags |= IO_FLAG_DIRECT_IO;
+	if (flags & EXT2_FLAG_THREADS)
+		io_flags |= IO_FLAG_THREADS;
+	retval = manager->open(fs->device_name, io_flags, &fs->io);
+	if (retval)
+		goto cleanup;
+	if (io_options &&
+	    (retval = io_channel_set_options(fs->io, io_options)))
+		goto cleanup;
+	fs->image_io = fs->io;
+	fs->io->app_data = fs;
+	retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
+	if (retval)
+		goto cleanup;
+	if (flags & EXT2_FLAG_IMAGE_FILE) {
+		retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
+					&fs->image_header);
+		if (retval)
+			goto cleanup;
+		retval = io_channel_read_blk(fs->io, 0,
+					     -(int)sizeof(struct ext2_image_hdr),
+					     fs->image_header);
+		if (retval)
+			goto cleanup;
+		if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE)
+			return EXT2_ET_MAGIC_E2IMAGE;
+		superblock = 1;
+		block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize);
+	}
+
+	/*
+	 * If the user specifies a specific block # for the
+	 * superblock, then he/she must also specify the block size!
+	 * Otherwise, read the master superblock located at offset
+	 * SUPERBLOCK_OFFSET from the start of the partition.
+	 *
+	 * Note: we only save a backup copy of the superblock if we
+	 * are reading the superblock from the primary superblock location.
+	 */
+	if (superblock) {
+		if (!block_size) {
+			retval = EXT2_ET_INVALID_ARGUMENT;
+			goto cleanup;
+		}
+		io_channel_set_blksize(fs->io, block_size);
+		group_block = superblock;
+		fs->orig_super = 0;
+	} else {
+		io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
+		superblock = 1;
+		group_block = 0;
+		retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
+		if (retval)
+			goto cleanup;
+	}
+retry:
+	retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
+				     fs->super);
+	if (retval)
+		goto cleanup;
+	if (fs->orig_super)
+		memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
+
+	if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
+		retval = 0;
+		if (!ext2fs_verify_csum_type(fs, fs->super))
+			retval = EXT2_ET_UNKNOWN_CSUM;
+		if (!ext2fs_superblock_csum_verify(fs, fs->super)) {
+			if (csum_retries++ < 3)
+				goto retry;
+			retval = EXT2_ET_SB_CSUM_INVALID;
+		}
+	}
+
+#ifdef WORDS_BIGENDIAN
+	fs->flags |= EXT2_FLAG_SWAP_BYTES;
+	ext2fs_swap_super(fs->super);
+#else
+	if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
+		retval = EXT2_ET_UNIMPLEMENTED;
+		goto cleanup;
+	}
+#endif
+
+	if (fs->super->s_magic != EXT2_SUPER_MAGIC)
+		retval = EXT2_ET_BAD_MAGIC;
+	if (retval)
+		goto cleanup;
+
+	if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
+		retval = EXT2_ET_REV_TOO_HIGH;
+		goto cleanup;
+	}
+
+	/*
+	 * Check for feature set incompatibility
+	 */
+	if (!(flags & EXT2_FLAG_FORCE)) {
+		features = fs->super->s_feature_incompat;
+#ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
+		if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
+			features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
+#endif
+		if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
+			retval = EXT2_ET_UNSUPP_FEATURE;
+			goto cleanup;
+		}
+
+		features = fs->super->s_feature_ro_compat;
+#ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
+		if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
+			features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
+#endif
+		if ((flags & EXT2_FLAG_RW) &&
+		    (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
+			retval = EXT2_ET_RO_UNSUPP_FEATURE;
+			goto cleanup;
+		}
+
+		if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
+		    ext2fs_has_feature_journal_dev(fs->super)) {
+			retval = EXT2_ET_UNSUPP_FEATURE;
+			goto cleanup;
+		}
+	}
+
+	if ((fs->super->s_log_block_size >
+	     (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) ||
+	    (fs->super->s_log_cluster_size >
+	     (unsigned) (EXT2_MAX_CLUSTER_LOG_SIZE - EXT2_MIN_CLUSTER_LOG_SIZE)) ||
+	    (fs->super->s_log_block_size > fs->super->s_log_cluster_size) ||
+	    (fs->super->s_log_groups_per_flex > 31)) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+
+	/*
+	 * bigalloc requires cluster-aware bitfield operations, which at the
+	 * moment means we need EXT2_FLAG_64BITS.
+	 */
+	if (ext2fs_has_feature_bigalloc(fs->super) &&
+	    !(flags & EXT2_FLAG_64BITS)) {
+		retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
+		goto cleanup;
+	}
+
+	if (!ext2fs_has_feature_bigalloc(fs->super) &&
+	    (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
+	inode_size = EXT2_INODE_SIZE(fs->super);
+	if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
+	    (inode_size > fs->blocksize) ||
+	    (inode_size & (inode_size - 1))) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+
+	/* Enforce the block group descriptor size */
+	if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
+	    ext2fs_has_feature_64bit(fs->super)) {
+		unsigned desc_size = fs->super->s_desc_size;
+
+		if ((desc_size < EXT2_MIN_DESC_SIZE_64BIT) ||
+		    (desc_size > EXT2_MAX_DESC_SIZE) ||
+		    (desc_size & (desc_size - 1)) != 0) {
+			retval = EXT2_ET_BAD_DESC_SIZE;
+			goto cleanup;
+		}
+	}
+
+	fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
+		fs->super->s_log_block_size;
+	if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
+	    EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
+				       EXT2_INODE_SIZE(fs->super) +
+				       EXT2_BLOCK_SIZE(fs->super) - 1) /
+				      EXT2_BLOCK_SIZE(fs->super));
+	if (block_size) {
+		if (block_size != fs->blocksize) {
+			retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
+			goto cleanup;
+		}
+	}
+	/*
+	 * Set the blocksize to the filesystem's blocksize.
+	 */
+	io_channel_set_blksize(fs->io, fs->blocksize);
+
+	/*
+	 * If this is an external journal device, don't try to read
+	 * the group descriptors, because they're not there.
+	 */
+	if (ext2fs_has_feature_journal_dev(fs->super)) {
+		fs->group_desc_count = 0;
+		*ret_fs = fs;
+		return 0;
+	}
+
+	if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	/* Precompute the FS UUID to seed other checksums */
+	ext2fs_init_csum_seed(fs);
+
+	/*
+	 * Read group descriptors
+	 */
+	blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
+	if (blocks_per_group < 8 ||
+	    blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
+	    fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
+           EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
+           fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
+				       fs->super->s_first_data_block,
+				       blocks_per_group);
+	if (groups_cnt >> 32) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	fs->group_desc_count = 	groups_cnt;
+	if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
+	    (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
+	    fs->super->s_inodes_count) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
+					  EXT2_DESC_PER_BLOCK(fs->super));
+	if (ext2fs_has_feature_meta_bg(fs->super) &&
+	    (fs->super->s_first_meta_bg > fs->desc_blocks) &&
+	    !(flags & EXT2_FLAG_IGNORE_SB_ERRORS)) {
+		retval = EXT2_ET_CORRUPT_SUPERBLOCK;
+		goto cleanup;
+	}
+	if (flags & EXT2_FLAG_SUPER_ONLY)
+		goto skip_read_bg;
+	retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
+				&fs->group_desc);
+	if (retval)
+		goto cleanup;
+	if (!group_block)
+		group_block = fs->super->s_first_data_block;
+	/*
+	 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
+	 * so we must increment block numbers to any group 0 items.
+	 *
+	 * However, we cannot touch group_block directly because in the meta_bg
+	 * case, the ext2fs_descriptor_block_loc2() function will interpret
+	 * group_block != s_first_data_block to mean that we want to access the
+	 * backup group descriptors.  This is not what we want if the caller
+	 * set superblock == 0 (i.e. auto-detect the superblock), which is
+	 * what's going on here.
+	 */
+	if (group_block == 0 && fs->blocksize == 1024)
+		group_zero_adjust = 1;
+	dest = (char *) fs->group_desc;
+#ifdef WORDS_BIGENDIAN
+	groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
+#endif
+	if (ext2fs_has_feature_meta_bg(fs->super) &&
+	    !(flags & EXT2_FLAG_IMAGE_FILE)) {
+		first_meta_bg = fs->super->s_first_meta_bg;
+		if (first_meta_bg > fs->desc_blocks)
+			first_meta_bg = fs->desc_blocks;
+	} else
+		first_meta_bg = fs->desc_blocks;
+	if (first_meta_bg) {
+		retval = io_channel_read_blk(fs->io, group_block +
+					     group_zero_adjust + 1,
+					     first_meta_bg, dest);
+		if (retval)
+			goto cleanup;
+#ifdef WORDS_BIGENDIAN
+		gdp = (struct ext2_group_desc *) dest;
+		for (j=0; j < groups_per_block*first_meta_bg; j++) {
+			gdp = ext2fs_group_desc(fs, fs->group_desc, j);
+			if (gdp)
+				ext2fs_swap_group_desc2(fs, gdp);
+		}
+#endif
+		dest += fs->blocksize*first_meta_bg;
+	}
+
+	for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
+		blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
+		io_channel_cache_readahead(fs->io, blk, 1);
+	}
+
+	for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
+		blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
+		retval = io_channel_read_blk64(fs->io, blk, 1, dest);
+		if (retval)
+			goto cleanup;
+#ifdef WORDS_BIGENDIAN
+		for (j=0; j < groups_per_block; j++) {
+			gdp = ext2fs_group_desc(fs, fs->group_desc,
+						i * groups_per_block + j);
+			if (gdp)
+				ext2fs_swap_group_desc2(fs, gdp);
+		}
+#endif
+		dest += fs->blocksize;
+	}
+
+	fs->stride = fs->super->s_raid_stride;
+
+	/*
+	 * If recovery is from backup superblock, Clear _UNININT flags &
+	 * reset bg_itable_unused to zero
+	 */
+	if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
+		dgrp_t group;
+
+		for (group = 0; group < fs->group_desc_count; group++) {
+			ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
+			ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
+			ext2fs_bg_itable_unused_set(fs, group, 0);
+			/* The checksum will be reset later, but fix it here
+			 * anyway to avoid printing a lot of spurious errors. */
+			ext2fs_group_desc_csum_set(fs, group);
+		}
+		if (fs->flags & EXT2_FLAG_RW)
+			ext2fs_mark_super_dirty(fs);
+	}
+skip_read_bg:
+	if (ext2fs_has_feature_mmp(fs->super) &&
+	    !(flags & EXT2_FLAG_SKIP_MMP) &&
+	    (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
+		retval = ext2fs_mmp_start(fs);
+		if (retval) {
+			fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
+			ext2fs_mmp_stop(fs);
+			goto cleanup;
+		}
+	}
+
+	if (fs->flags & EXT2_FLAG_SHARE_DUP) {
+		fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
+					block_sha_map_free_entry, 4096);
+		if (!fs->block_sha_map) {
+			retval = EXT2_ET_NO_MEMORY;
+			goto cleanup;
+		}
+		ext2fs_set_feature_shared_blocks(fs->super);
+	}
+
+	if (ext2fs_has_feature_casefold(fs->super))
+		fs->encoding = ext2fs_load_nls_table(fs->super->s_encoding);
+
+	fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
+	*ret_fs = fs;
+
+	return 0;
+cleanup:
+	if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
+		ext2fs_free(fs);
+		fs = NULL;
+	}
+	*ret_fs = fs;
+	return retval;
+}
+
+/*
+ * Set/get the filesystem data I/O channel.
+ *
+ * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
+ */
+errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
+{
+	if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
+		return EXT2_ET_NOT_IMAGE_FILE;
+	if (old_io) {
+		*old_io = (fs->image_io == fs->io) ? 0 : fs->io;
+	}
+	return 0;
+}
+
+errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
+{
+	if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
+		return EXT2_ET_NOT_IMAGE_FILE;
+	fs->io = new_io ? new_io : fs->image_io;
+	return 0;
+}
+
+errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
+{
+	errcode_t err;
+
+	if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
+		return EXT2_ET_NOT_IMAGE_FILE;
+	err = io_channel_set_blksize(new_io, fs->blocksize);
+	if (err)
+		return err;
+	if ((new_io == fs->image_io) || (new_io == fs->io))
+		return 0;
+	if ((fs->image_io != fs->io) &&
+	    fs->image_io)
+		io_channel_close(fs->image_io);
+	if (fs->io)
+		io_channel_close(fs->io);
+	fs->io = fs->image_io = new_io;
+	fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
+		EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
+	fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
+	return 0;
+}