271 lines
6.5 KiB
C
271 lines
6.5 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* inode_io.c --- This is allows an inode in an ext2 filesystem image
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* to be accessed via the I/O manager interface.
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*
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* Copyright (C) 2002 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include <stdio.h>
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#if HAVE_ERRNO_H
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#include <errno.h>
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#endif
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#include <time.h>
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#include "ext2_fs.h"
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#include "ext2fs.h"
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/*
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* For checking structure magic numbers...
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*/
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#define EXT2_CHECK_MAGIC(struct, code) \
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if ((struct)->magic != (code)) return (code)
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struct inode_private_data {
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int magic;
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char name[32];
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ext2_file_t file;
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ext2_filsys fs;
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ext2_ino_t ino;
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struct ext2_inode inode;
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int flags;
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struct inode_private_data *next;
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};
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#define CHANNEL_HAS_INODE 0x8000
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static struct inode_private_data *top_intern;
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static int ino_unique = 0;
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static errcode_t inode_open(const char *name, int flags, io_channel *channel);
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static errcode_t inode_close(io_channel channel);
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static errcode_t inode_set_blksize(io_channel channel, int blksize);
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static errcode_t inode_read_blk(io_channel channel, unsigned long block,
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int count, void *data);
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static errcode_t inode_write_blk(io_channel channel, unsigned long block,
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int count, const void *data);
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static errcode_t inode_flush(io_channel channel);
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static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
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int size, const void *data);
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static struct struct_io_manager struct_inode_manager = {
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EXT2_ET_MAGIC_IO_MANAGER,
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"Inode I/O Manager",
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inode_open,
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inode_close,
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inode_set_blksize,
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inode_read_blk,
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inode_write_blk,
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inode_flush,
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inode_write_byte
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};
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io_manager inode_io_manager = &struct_inode_manager;
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errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
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struct ext2_inode *inode,
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char **name)
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{
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struct inode_private_data *data;
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errcode_t retval;
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if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
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&data)))
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return retval;
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data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
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sprintf(data->name, "%u:%d", ino, ino_unique++);
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data->file = 0;
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data->fs = fs;
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data->ino = ino;
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data->flags = 0;
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if (inode) {
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memcpy(&data->inode, inode, sizeof(struct ext2_inode));
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data->flags |= CHANNEL_HAS_INODE;
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}
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data->next = top_intern;
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top_intern = data;
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*name = data->name;
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return 0;
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}
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errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
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char **name)
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{
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return ext2fs_inode_io_intern2(fs, ino, NULL, name);
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}
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static errcode_t inode_open(const char *name, int flags, io_channel *channel)
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{
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io_channel io = NULL;
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struct inode_private_data *prev, *data = NULL;
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errcode_t retval;
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int open_flags;
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if (name == 0)
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return EXT2_ET_BAD_DEVICE_NAME;
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for (data = top_intern, prev = NULL; data;
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prev = data, data = data->next)
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if (strcmp(name, data->name) == 0)
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break;
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if (!data)
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return ENOENT;
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if (prev)
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prev->next = data->next;
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else
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top_intern = data->next;
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retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
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if (retval)
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goto cleanup;
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memset(io, 0, sizeof(struct struct_io_channel));
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io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
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io->manager = inode_io_manager;
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retval = ext2fs_get_mem(strlen(name)+1, &io->name);
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if (retval)
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goto cleanup;
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strcpy(io->name, name);
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io->private_data = data;
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io->block_size = 1024;
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io->read_error = 0;
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io->write_error = 0;
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io->refcount = 1;
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open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
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retval = ext2fs_file_open2(data->fs, data->ino,
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(data->flags & CHANNEL_HAS_INODE) ?
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&data->inode : 0, open_flags,
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&data->file);
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if (retval)
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goto cleanup;
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*channel = io;
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return 0;
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cleanup:
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if (data) {
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ext2fs_free_mem(&data);
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}
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if (io)
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ext2fs_free_mem(&io);
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return retval;
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}
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static errcode_t inode_close(io_channel channel)
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{
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struct inode_private_data *data;
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errcode_t retval = 0;
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EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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data = (struct inode_private_data *) channel->private_data;
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EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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if (--channel->refcount > 0)
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return 0;
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retval = ext2fs_file_close(data->file);
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ext2fs_free_mem(&channel->private_data);
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if (channel->name)
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ext2fs_free_mem(&channel->name);
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ext2fs_free_mem(&channel);
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return retval;
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}
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static errcode_t inode_set_blksize(io_channel channel, int blksize)
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{
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struct inode_private_data *data;
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EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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data = (struct inode_private_data *) channel->private_data;
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EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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channel->block_size = blksize;
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return 0;
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}
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static errcode_t inode_read_blk(io_channel channel, unsigned long block,
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int count, void *buf)
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{
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struct inode_private_data *data;
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errcode_t retval;
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EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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data = (struct inode_private_data *) channel->private_data;
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EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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if ((retval = ext2fs_file_lseek(data->file,
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block * channel->block_size,
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EXT2_SEEK_SET, 0)))
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return retval;
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count = (count < 0) ? -count : (count * channel->block_size);
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return ext2fs_file_read(data->file, buf, count, 0);
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}
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static errcode_t inode_write_blk(io_channel channel, unsigned long block,
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int count, const void *buf)
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{
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struct inode_private_data *data;
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errcode_t retval;
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EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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data = (struct inode_private_data *) channel->private_data;
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EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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if ((retval = ext2fs_file_lseek(data->file,
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block * channel->block_size,
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EXT2_SEEK_SET, 0)))
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return retval;
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count = (count < 0) ? -count : (count * channel->block_size);
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return ext2fs_file_write(data->file, buf, count, 0);
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}
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static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
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int size, const void *buf)
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{
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struct inode_private_data *data;
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errcode_t retval = 0;
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EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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data = (struct inode_private_data *) channel->private_data;
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EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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if ((retval = ext2fs_file_lseek(data->file, offset,
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EXT2_SEEK_SET, 0)))
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return retval;
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return ext2fs_file_write(data->file, buf, size, 0);
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}
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/*
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* Flush data buffers to disk.
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*/
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static errcode_t inode_flush(io_channel channel)
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{
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struct inode_private_data *data;
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EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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data = (struct inode_private_data *) channel->private_data;
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EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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return ext2fs_file_flush(data->file);
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}
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