fs/ext4/ext4fs.c - filogic/uboot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2011 - 2012 Samsung Electronics
  * EXT4 filesystem implementation in Uboot by
  * Uma Shankar <uma.shankar@samsung.com>
  * Manjunatha C Achar <a.manjunatha@samsung.com>
  *
  * ext4ls and ext4load : Based on ext2 ls and load support in Uboot.
  *		       Ext4 read optimization taken from Open-Moko
  *		       Qi bootloader
  *
  * (C) Copyright 2004
  * esd gmbh <www.esd-electronics.com>
  * Reinhard Arlt <reinhard.arlt@esd-electronics.com>
  *
  * based on code from grub2 fs/ext2.c and fs/fshelp.c by
  * GRUB  --  GRand Unified Bootloader
  * Copyright (C) 2003, 2004  Free Software Foundation, Inc.
  *
  * ext4write : Based on generic ext4 protocol.
  */

 #include <blk.h>
 #include <div64.h>
 #include <errno.h>
 #include <ext_common.h>
 #include <ext4fs.h>
 #include <malloc.h>
 #include <part.h>
 #include <u-boot/uuid.h>
 #include "ext4_common.h"

 int ext4fs_symlinknest;
 struct ext_filesystem ext_fs;

 /**
  * struct ext4_dir_stream - ext4 directory stream
  *
  * @parent: partition data used by fs layer.
  * This field must be at the beginning of the structure.
  * All other fields are private to the ext4 driver.
  * @root:	root directory node
  * @dir:	directory node
  * @dirent:	directory stream entry
  * @fpos:	file position in directory
  */
 struct ext4_dir_stream {
 	struct fs_dir_stream parent;
 	char *dirname;
 	struct fs_dirent dirent;
 	unsigned int fpos;
 };

 struct ext_filesystem *get_fs(void)
 {
 	return &ext_fs;
 }

 void ext4fs_free_node(struct ext2fs_node *node, struct ext2fs_node *currroot)
 {
 	if ((node != &ext4fs_root->diropen) && (node != currroot))
 		free(node);
 }

 /*
  * Taken from openmoko-kernel mailing list: By Andy green
  * Optimized read file API : collects and defers contiguous sector
  * reads into one potentially more efficient larger sequential read action
  */
 int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
 		loff_t len, char *buf, loff_t *actread)
 {
 	struct ext_filesystem *fs = get_fs();
 	int i;
 	lbaint_t blockcnt;
 	int log2blksz = fs->dev_desc->log2blksz;
 	int log2_fs_blocksize = LOG2_BLOCK_SIZE(node->data) - log2blksz;
 	int blocksize = (1 << (log2_fs_blocksize + log2blksz));
 	unsigned int filesize = le32_to_cpu(node->inode.size);
 	lbaint_t previous_block_number = -1;
 	lbaint_t delayed_start = 0;
 	lbaint_t delayed_extent = 0;
 	lbaint_t delayed_skipfirst = 0;
 	lbaint_t delayed_next = 0;
 	char *delayed_buf = NULL;
 	char *start_buf = buf;
 	short status;
 	struct ext_block_cache cache;

 	ext_cache_init(&cache);

 	/* Adjust len so it we can't read past the end of the file. */
 	if (len + pos > filesize)
 		len = (filesize - pos);

 	if (blocksize <= 0 || len <= 0) {
 		ext_cache_fini(&cache);
 		return -1;
 	}

 	blockcnt = lldiv(((len + pos) + blocksize - 1), blocksize);

 	for (i = lldiv(pos, blocksize); i < blockcnt; i++) {
 		long int blknr;
 		int blockoff = pos - (blocksize * i);
 		int blockend = blocksize;
 		int skipfirst = 0;
 		blknr = read_allocated_block(&node->inode, i, &cache);
 		if (blknr < 0) {
 			ext_cache_fini(&cache);
 			return -1;
 		}

 		blknr = blknr << log2_fs_blocksize;

 		/* Last block.  */
 		if (i == blockcnt - 1) {
 			blockend = (len + pos) - (blocksize * i);

 			/* The last portion is exactly blocksize. */
 			if (!blockend)
 				blockend = blocksize;
 		}

 		/* First block. */
 		if (i == lldiv(pos, blocksize)) {
 			skipfirst = blockoff;
 			blockend -= skipfirst;
 		}
 		if (blknr) {
 			int status;

 			if (previous_block_number != -1) {
 				if (delayed_next == blknr) {
 					delayed_extent += blockend;
 					delayed_next += blockend >> log2blksz;
 				} else {	/* spill */
 					status = ext4fs_devread(delayed_start,
 							delayed_skipfirst,
 							delayed_extent,
 							delayed_buf);
 					if (status == 0) {
 						ext_cache_fini(&cache);
 						return -1;
 					}
 					previous_block_number = blknr;
 					delayed_start = blknr;
 					delayed_extent = blockend;
 					delayed_skipfirst = skipfirst;
 					delayed_buf = buf;
 					delayed_next = blknr +
 						(blockend >> log2blksz);
 				}
 			} else {
 				previous_block_number = blknr;
 				delayed_start = blknr;
 				delayed_extent = blockend;
 				delayed_skipfirst = skipfirst;
 				delayed_buf = buf;
 				delayed_next = blknr +
 					(blockend >> log2blksz);
 			}
 		} else {
 			int n;
 			int n_left;
 			if (previous_block_number != -1) {
 				/* spill */
 				status = ext4fs_devread(delayed_start,
 							delayed_skipfirst,
 							delayed_extent,
 							delayed_buf);
 				if (status == 0) {
 					ext_cache_fini(&cache);
 					return -1;
 				}
 				previous_block_number = -1;
 			}
 			/* Zero no more than `len' bytes. */
 			n = blocksize - skipfirst;
 			n_left = len - ( buf - start_buf );
 			if (n > n_left)
 				n = n_left;
 			memset(buf, 0, n);
 		}
 		buf += blocksize - skipfirst;
 	}
 	if (previous_block_number != -1) {
 		/* spill */
 		status = ext4fs_devread(delayed_start,
 					delayed_skipfirst, delayed_extent,
 					delayed_buf);
 		if (status == 0) {
 			ext_cache_fini(&cache);
 			return -1;
 		}
 		previous_block_number = -1;
 	}

 	*actread  = len;
 	ext_cache_fini(&cache);
 	return 0;
 }

 int ext4fs_opendir(const char *dirname, struct fs_dir_stream **dirsp)
 {
 	struct ext4_dir_stream *dirs;
 	struct ext2fs_node *dir = NULL;
 	int ret;

 	*dirsp = NULL;

 	dirs = calloc(1, sizeof(struct ext4_dir_stream));
 	if (!dirs)
 		return -ENOMEM;
 	dirs->dirname = strdup(dirname);
 	if (!dirs) {
 		free(dirs);
 		return -ENOMEM;
 	}

 	ret = ext4fs_find_file(dirname, &ext4fs_root->diropen, &dir,
 			       FILETYPE_DIRECTORY);
 	if (ret == 1) {
 		ret = 0;
 		*dirsp = (struct fs_dir_stream *)dirs;
 	} else {
 		ret = -ENOENT;
 	}

 	if (dir)
 		ext4fs_free_node(dir, &ext4fs_root->diropen);

 	return ret;
 }

 int ext4fs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
 {
 	struct ext4_dir_stream *dirs = (struct ext4_dir_stream *)fs_dirs;
 	struct fs_dirent *dent = &dirs->dirent;
 	struct ext2fs_node *dir = NULL;
 	int ret;
 	loff_t actread;
 	struct ext2fs_node fdiro;
 	int len;
 	struct ext2_dirent dirent;

 	*dentp = NULL;

 	ret = ext4fs_find_file(dirs->dirname, &ext4fs_root->diropen, &dir,
 			       FILETYPE_DIRECTORY);
 	if (ret != 1) {
 		ret = -ENOENT;
 		goto out;
 	}
 	if (!dir->inode_read) {
 		ret = ext4fs_read_inode(dir->data, dir->ino, &dir->inode);
 		if (!ret) {
 			ret = -EIO;
 			goto out;
 		}
 	}

 	if (dirs->fpos >= le32_to_cpu(dir->inode.size))
 		return -ENOENT;

 	memset(dent, 0, sizeof(struct fs_dirent));

 	while (dirs->fpos < le32_to_cpu(dir->inode.size)) {
 		ret = ext4fs_read_file(dir, dirs->fpos,
 				       sizeof(struct ext2_dirent),
 				       (char *)&dirent, &actread);
 		if (ret < 0)
 			return -ret;

 		if (!dirent.direntlen)
 			return -EIO;

 		if (dirent.namelen)
 			break;

 		dirs->fpos += le16_to_cpu(dirent.direntlen);
 	}

 	len = min(FS_DIRENT_NAME_LEN - 1, (int)dirent.namelen);

 	ret = ext4fs_read_file(dir, dirs->fpos + sizeof(struct ext2_dirent),
 			       len, dent->name, &actread);
 	if (ret < 0)
 		goto out;
 	dent->name[len] = '\0';

 	fdiro.data = dir->data;
 	fdiro.ino = le32_to_cpu(dirent.inode);

 	ret = ext4fs_read_inode(dir->data, fdiro.ino, &fdiro.inode);
 	if (!ret) {
 		ret = -EIO;
 		goto out;
 	}

 	switch (le16_to_cpu(fdiro.inode.mode) & FILETYPE_INO_MASK) {
 	case FILETYPE_INO_DIRECTORY:
 		dent->type = FS_DT_DIR;
 		break;
 	case FILETYPE_INO_SYMLINK:
 		dent->type = FS_DT_LNK;
 		break;
 	case FILETYPE_INO_REG:
 		dent->type = FS_DT_REG;
 		break;
 	default:
 		dent->type = FILETYPE_UNKNOWN;
 	}

 	rtc_to_tm(fdiro.inode.atime, &dent->access_time);
 	rtc_to_tm(fdiro.inode.ctime, &dent->create_time);
 	rtc_to_tm(fdiro.inode.mtime, &dent->change_time);

 	dirs->fpos += le16_to_cpu(dirent.direntlen);
 	dent->size = fdiro.inode.size;
 	*dentp = dent;
 	ret = 0;

 out:
 	if (dir)
 		ext4fs_free_node(dir, &ext4fs_root->diropen);

 	return ret;
 }

 void ext4fs_closedir(struct fs_dir_stream *fs_dirs)
 {
 	struct ext4_dir_stream *dirs = (struct ext4_dir_stream *)fs_dirs;

 	if (!dirs)
 		return;

 	free(dirs->dirname);
 	free(dirs);
 }

 int ext4fs_exists(const char *filename)
 {
 	struct ext2fs_node *dirnode = NULL;
 	int filetype;
 	int ret;

 	if (!filename)
 		return 0;

 	ret = ext4fs_find_file1(filename, &ext4fs_root->diropen, &dirnode,
 				&filetype);
 	if (dirnode)
 		ext4fs_free_node(dirnode, &ext4fs_root->diropen);

 	return ret;
 }

 int ext4fs_size(const char *filename, loff_t *size)
 {
 	return ext4fs_open(filename, size);
 }

 int ext4fs_read(char *buf, loff_t offset, loff_t len, loff_t *actread)
 {
 	if (ext4fs_root == NULL || ext4fs_file == NULL)
 		return -1;

 	return ext4fs_read_file(ext4fs_file, offset, len, buf, actread);
 }

 int ext4fs_probe(struct blk_desc *fs_dev_desc,
 		 struct disk_partition *fs_partition)
 {
 	ext4fs_set_blk_dev(fs_dev_desc, fs_partition);

 	if (!ext4fs_mount()) {
 		ext4fs_close();
 		return -1;
 	}

 	return 0;
 }

 int ext4_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
 		   loff_t *len_read)
 {
 	loff_t file_len;
 	int ret;

 	ret = ext4fs_open(filename, &file_len);
 	if (ret < 0) {
 		printf("** File not found %s **\n", filename);
 		return -1;
 	}

 	if (len == 0)
 		len = file_len;

 	return ext4fs_read(buf, offset, len, len_read);
 }

 int ext4fs_uuid(char *uuid_str)
 {
 	if (ext4fs_root == NULL)
 		return -1;

 #ifdef CONFIG_LIB_UUID
 	uuid_bin_to_str((unsigned char *)ext4fs_root->sblock.unique_id,
 			uuid_str, UUID_STR_FORMAT_STD);

 	return 0;
 #else
 	return -ENOSYS;
 #endif
 }

 void ext_cache_init(struct ext_block_cache *cache)
 {
 	memset(cache, 0, sizeof(*cache));
 }

 void ext_cache_fini(struct ext_block_cache *cache)
 {
 	free(cache->buf);
 	ext_cache_init(cache);
 }

 int ext_cache_read(struct ext_block_cache *cache, lbaint_t block, int size)
 {
 	/* This could be more lenient, but this is simple and enough for now */
 	if (cache->buf && cache->block == block && cache->size == size)
 		return 1;
 	ext_cache_fini(cache);
 	cache->buf = memalign(ARCH_DMA_MINALIGN, size);
 	if (!cache->buf)
 		return 0;
 	if (!ext4fs_devread(block, 0, size, cache->buf)) {
 		ext_cache_fini(cache);
 		return 0;
 	}
 	cache->block = block;
 	cache->size = size;
 	return 1;
 }
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* (C) Copyright 2011 - 2012 Samsung Electronics
	* EXT4 filesystem implementation in Uboot by
	* Uma Shankar <uma.shankar@samsung.com>
	* Manjunatha C Achar <a.manjunatha@samsung.com>
	*
	* ext4ls and ext4load : Based on ext2 ls and load support in Uboot.
	* Ext4 read optimization taken from Open-Moko
	* Qi bootloader
	*
	* (C) Copyright 2004
	* esd gmbh <www.esd-electronics.com>
	* Reinhard Arlt <reinhard.arlt@esd-electronics.com>
	*
	* based on code from grub2 fs/ext2.c and fs/fshelp.c by
	* GRUB -- GRand Unified Bootloader
	* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
	*
	* ext4write : Based on generic ext4 protocol.
	*/

	#include <blk.h>
	#include <div64.h>
	#include <errno.h>
	#include <ext_common.h>
	#include <ext4fs.h>
	#include <malloc.h>
	#include <part.h>
	#include <u-boot/uuid.h>
	#include "ext4_common.h"

	int ext4fs_symlinknest;
	struct ext_filesystem ext_fs;

	/**
	* struct ext4_dir_stream - ext4 directory stream
	*
	* @parent: partition data used by fs layer.
	* This field must be at the beginning of the structure.
	* All other fields are private to the ext4 driver.
	* @root: root directory node
	* @dir: directory node
	* @dirent: directory stream entry
	* @fpos: file position in directory
	*/
	struct ext4_dir_stream {
	struct fs_dir_stream parent;
	char *dirname;
	struct fs_dirent dirent;
	unsigned int fpos;
	};

	struct ext_filesystem *get_fs(void)
	{
	return &ext_fs;
	}

	void ext4fs_free_node(struct ext2fs_node node, struct ext2fs_node currroot)
	{
	if ((node != &ext4fs_root->diropen) && (node != currroot))
	free(node);
	}

	/*
	* Taken from openmoko-kernel mailing list: By Andy green
	* Optimized read file API : collects and defers contiguous sector
	* reads into one potentially more efficient larger sequential read action
	*/
	int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
	loff_t len, char buf, loff_t actread)
	{
	struct ext_filesystem *fs = get_fs();
	int i;
	lbaint_t blockcnt;
	int log2blksz = fs->dev_desc->log2blksz;
	int log2_fs_blocksize = LOG2_BLOCK_SIZE(node->data) - log2blksz;
	int blocksize = (1 << (log2_fs_blocksize + log2blksz));
	unsigned int filesize = le32_to_cpu(node->inode.size);
	lbaint_t previous_block_number = -1;
	lbaint_t delayed_start = 0;
	lbaint_t delayed_extent = 0;
	lbaint_t delayed_skipfirst = 0;
	lbaint_t delayed_next = 0;
	char *delayed_buf = NULL;
	char *start_buf = buf;
	short status;
	struct ext_block_cache cache;

	ext_cache_init(&cache);

	/* Adjust len so it we can't read past the end of the file. */
	if (len + pos > filesize)
	len = (filesize - pos);

	if (blocksize <= 0 \|\| len <= 0) {
	ext_cache_fini(&cache);
	return -1;
	}

	blockcnt = lldiv(((len + pos) + blocksize - 1), blocksize);

	for (i = lldiv(pos, blocksize); i < blockcnt; i++) {
	long int blknr;
	int blockoff = pos - (blocksize * i);
	int blockend = blocksize;
	int skipfirst = 0;
	blknr = read_allocated_block(&node->inode, i, &cache);
	if (blknr < 0) {
	ext_cache_fini(&cache);
	return -1;
	}

	blknr = blknr << log2_fs_blocksize;

	/* Last block. */
	if (i == blockcnt - 1) {
	blockend = (len + pos) - (blocksize * i);

	/* The last portion is exactly blocksize. */
	if (!blockend)
	blockend = blocksize;
	}

	/* First block. */
	if (i == lldiv(pos, blocksize)) {
	skipfirst = blockoff;
	blockend -= skipfirst;
	}
	if (blknr) {
	int status;

	if (previous_block_number != -1) {
	if (delayed_next == blknr) {
	delayed_extent += blockend;
	delayed_next += blockend >> log2blksz;
	} else { /* spill */
	status = ext4fs_devread(delayed_start,
	delayed_skipfirst,
	delayed_extent,
	delayed_buf);
	if (status == 0) {
	ext_cache_fini(&cache);
	return -1;
	}
	previous_block_number = blknr;
	delayed_start = blknr;
	delayed_extent = blockend;
	delayed_skipfirst = skipfirst;
	delayed_buf = buf;
	delayed_next = blknr +
	(blockend >> log2blksz);
	}
	} else {
	previous_block_number = blknr;
	delayed_start = blknr;
	delayed_extent = blockend;
	delayed_skipfirst = skipfirst;
	delayed_buf = buf;
	delayed_next = blknr +
	(blockend >> log2blksz);
	}
	} else {
	int n;
	int n_left;
	if (previous_block_number != -1) {
	/* spill */
	status = ext4fs_devread(delayed_start,
	delayed_skipfirst,
	delayed_extent,
	delayed_buf);
	if (status == 0) {
	ext_cache_fini(&cache);
	return -1;
	}
	previous_block_number = -1;
	}
	/* Zero no more than `len' bytes. */
	n = blocksize - skipfirst;
	n_left = len - ( buf - start_buf );
	if (n > n_left)
	n = n_left;
	memset(buf, 0, n);
	}
	buf += blocksize - skipfirst;
	}
	if (previous_block_number != -1) {
	/* spill */
	status = ext4fs_devread(delayed_start,
	delayed_skipfirst, delayed_extent,
	delayed_buf);
	if (status == 0) {
	ext_cache_fini(&cache);
	return -1;
	}
	previous_block_number = -1;
	}

	*actread = len;
	ext_cache_fini(&cache);
	return 0;
	}

	int ext4fs_opendir(const char dirname, struct fs_dir_stream *dirsp)
	{
	struct ext4_dir_stream *dirs;
	struct ext2fs_node *dir = NULL;
	int ret;

	*dirsp = NULL;

	dirs = calloc(1, sizeof(struct ext4_dir_stream));
	if (!dirs)
	return -ENOMEM;
	dirs->dirname = strdup(dirname);
	if (!dirs) {
	free(dirs);
	return -ENOMEM;
	}

	ret = ext4fs_find_file(dirname, &ext4fs_root->diropen, &dir,
	FILETYPE_DIRECTORY);
	if (ret == 1) {
	ret = 0;
	dirsp = (struct fs_dir_stream )dirs;
	} else {
	ret = -ENOENT;
	}

	if (dir)
	ext4fs_free_node(dir, &ext4fs_root->diropen);

	return ret;
	}

	int ext4fs_readdir(struct fs_dir_stream fs_dirs, struct fs_dirent *dentp)
	{
	struct ext4_dir_stream dirs = (struct ext4_dir_stream )fs_dirs;
	struct fs_dirent *dent = &dirs->dirent;
	struct ext2fs_node *dir = NULL;
	int ret;
	loff_t actread;
	struct ext2fs_node fdiro;
	int len;
	struct ext2_dirent dirent;

	*dentp = NULL;

	ret = ext4fs_find_file(dirs->dirname, &ext4fs_root->diropen, &dir,
	FILETYPE_DIRECTORY);
	if (ret != 1) {
	ret = -ENOENT;
	goto out;
	}
	if (!dir->inode_read) {
	ret = ext4fs_read_inode(dir->data, dir->ino, &dir->inode);
	if (!ret) {
	ret = -EIO;
	goto out;
	}
	}

	if (dirs->fpos >= le32_to_cpu(dir->inode.size))
	return -ENOENT;

	memset(dent, 0, sizeof(struct fs_dirent));

	while (dirs->fpos < le32_to_cpu(dir->inode.size)) {
	ret = ext4fs_read_file(dir, dirs->fpos,
	sizeof(struct ext2_dirent),
	(char *)&dirent, &actread);
	if (ret < 0)
	return -ret;

	if (!dirent.direntlen)
	return -EIO;

	if (dirent.namelen)
	break;

	dirs->fpos += le16_to_cpu(dirent.direntlen);
	}

	len = min(FS_DIRENT_NAME_LEN - 1, (int)dirent.namelen);

	ret = ext4fs_read_file(dir, dirs->fpos + sizeof(struct ext2_dirent),
	len, dent->name, &actread);
	if (ret < 0)
	goto out;
	dent->name[len] = '\0';

	fdiro.data = dir->data;
	fdiro.ino = le32_to_cpu(dirent.inode);

	ret = ext4fs_read_inode(dir->data, fdiro.ino, &fdiro.inode);
	if (!ret) {
	ret = -EIO;
	goto out;
	}

	switch (le16_to_cpu(fdiro.inode.mode) & FILETYPE_INO_MASK) {
	case FILETYPE_INO_DIRECTORY:
	dent->type = FS_DT_DIR;
	break;
	case FILETYPE_INO_SYMLINK:
	dent->type = FS_DT_LNK;
	break;
	case FILETYPE_INO_REG:
	dent->type = FS_DT_REG;
	break;
	default:
	dent->type = FILETYPE_UNKNOWN;
	}

	rtc_to_tm(fdiro.inode.atime, &dent->access_time);
	rtc_to_tm(fdiro.inode.ctime, &dent->create_time);
	rtc_to_tm(fdiro.inode.mtime, &dent->change_time);

	dirs->fpos += le16_to_cpu(dirent.direntlen);
	dent->size = fdiro.inode.size;
	*dentp = dent;
	ret = 0;

	out:
	if (dir)
	ext4fs_free_node(dir, &ext4fs_root->diropen);

	return ret;
	}

	void ext4fs_closedir(struct fs_dir_stream *fs_dirs)
	{
	struct ext4_dir_stream dirs = (struct ext4_dir_stream )fs_dirs;

	if (!dirs)
	return;

	free(dirs->dirname);
	free(dirs);
	}

	int ext4fs_exists(const char *filename)
	{
	struct ext2fs_node *dirnode = NULL;
	int filetype;
	int ret;

	if (!filename)
	return 0;

	ret = ext4fs_find_file1(filename, &ext4fs_root->diropen, &dirnode,
	&filetype);
	if (dirnode)
	ext4fs_free_node(dirnode, &ext4fs_root->diropen);

	return ret;
	}

	int ext4fs_size(const char filename, loff_t size)
	{
	return ext4fs_open(filename, size);
	}

	int ext4fs_read(char buf, loff_t offset, loff_t len, loff_t actread)
	{
	if (ext4fs_root == NULL \|\| ext4fs_file == NULL)
	return -1;

	return ext4fs_read_file(ext4fs_file, offset, len, buf, actread);
	}

	int ext4fs_probe(struct blk_desc *fs_dev_desc,
	struct disk_partition *fs_partition)
	{
	ext4fs_set_blk_dev(fs_dev_desc, fs_partition);

	if (!ext4fs_mount()) {
	ext4fs_close();
	return -1;
	}

	return 0;
	}

	int ext4_read_file(const char filename, void buf, loff_t offset, loff_t len,
	loff_t *len_read)
	{
	loff_t file_len;
	int ret;

	ret = ext4fs_open(filename, &file_len);
	if (ret < 0) {
	printf(" File not found %s \n", filename);
	return -1;
	}

	if (len == 0)
	len = file_len;

	return ext4fs_read(buf, offset, len, len_read);
	}

	int ext4fs_uuid(char *uuid_str)
	{
	if (ext4fs_root == NULL)
	return -1;

	#ifdef CONFIG_LIB_UUID
	uuid_bin_to_str((unsigned char *)ext4fs_root->sblock.unique_id,
	uuid_str, UUID_STR_FORMAT_STD);

	return 0;
	#else
	return -ENOSYS;
	#endif
	}

	void ext_cache_init(struct ext_block_cache *cache)
	{
	memset(cache, 0, sizeof(*cache));
	}

	void ext_cache_fini(struct ext_block_cache *cache)
	{
	free(cache->buf);
	ext_cache_init(cache);
	}

	int ext_cache_read(struct ext_block_cache *cache, lbaint_t block, int size)
	{
	/* This could be more lenient, but this is simple and enough for now */
	if (cache->buf && cache->block == block && cache->size == size)
	return 1;
	ext_cache_fini(cache);
	cache->buf = memalign(ARCH_DMA_MINALIGN, size);
	if (!cache->buf)
	return 0;
	if (!ext4fs_devread(block, 0, size, cache->buf)) {
	ext_cache_fini(cache);
	return 0;
	}
	cache->block = block;
	cache->size = size;
	return 1;
	}