[1765] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * inode_io.c --- This is allows an inode in an ext2 filesystem image
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| 4 | * to be accessed via the I/O manager interface.
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| 5 | *
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| 6 | * Copyright (C) 2002 Theodore Ts'o.
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| 7 | *
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| 8 | * %Begin-Header%
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| 9 | * This file may be redistributed under the terms of the GNU Public
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| 10 | * License.
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| 11 | * %End-Header%
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| 12 | */
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| 13 |
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| 14 | #include <stdio.h>
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| 15 | #include <string.h>
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| 16 | #if HAVE_UNISTD_H
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| 17 | #include <unistd.h>
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| 18 | #endif
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| 19 | #if HAVE_ERRNO_H
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| 20 | #include <errno.h>
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| 21 | #endif
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| 22 | #include <time.h>
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| 23 |
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| 24 | #include "ext2_fs.h"
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| 25 | #include "ext2fs.h"
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| 26 |
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| 27 | /*
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| 28 | * For checking structure magic numbers...
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| 29 | */
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| 30 |
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| 31 | #define EXT2_CHECK_MAGIC(struct, code) \
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| 32 | if ((struct)->magic != (code)) return (code)
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| 33 |
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| 34 | struct inode_private_data {
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| 35 | int magic;
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| 36 | char name[32];
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| 37 | ext2_file_t file;
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| 38 | ext2_filsys fs;
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| 39 | ext2_ino_t ino;
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| 40 | struct ext2_inode inode;
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| 41 | int flags;
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| 42 | struct inode_private_data *next;
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| 43 | };
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| 44 |
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| 45 | #define CHANNEL_HAS_INODE 0x8000
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| 46 |
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| 47 | static struct inode_private_data *top_intern;
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| 48 | static int ino_unique = 0;
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| 49 |
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| 50 | static errcode_t inode_open(const char *name, int flags, io_channel *channel);
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| 51 | static errcode_t inode_close(io_channel channel);
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| 52 | static errcode_t inode_set_blksize(io_channel channel, int blksize);
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| 53 | static errcode_t inode_read_blk(io_channel channel, unsigned long block,
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| 54 | int count, void *data);
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| 55 | static errcode_t inode_write_blk(io_channel channel, unsigned long block,
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| 56 | int count, const void *data);
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| 57 | static errcode_t inode_flush(io_channel channel);
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| 58 | static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
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| 59 | int size, const void *data);
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| 60 |
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| 61 | static struct struct_io_manager struct_inode_manager = {
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| 62 | EXT2_ET_MAGIC_IO_MANAGER,
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| 63 | "Inode I/O Manager",
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| 64 | inode_open,
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| 65 | inode_close,
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| 66 | inode_set_blksize,
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| 67 | inode_read_blk,
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| 68 | inode_write_blk,
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| 69 | inode_flush,
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| 70 | inode_write_byte
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| 71 | };
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| 72 |
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| 73 | io_manager inode_io_manager = &struct_inode_manager;
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| 74 |
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| 75 | errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
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| 76 | struct ext2_inode *inode,
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| 77 | char **name)
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| 78 | {
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| 79 | struct inode_private_data *data;
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| 80 | errcode_t retval;
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| 81 |
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| 82 | if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
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| 83 | &data)))
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| 84 | return retval;
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| 85 | data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
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| 86 | sprintf(data->name, "%u:%d", ino, ino_unique++);
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| 87 | data->file = 0;
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| 88 | data->fs = fs;
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| 89 | data->ino = ino;
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| 90 | data->flags = 0;
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| 91 | if (inode) {
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| 92 | memcpy(&data->inode, inode, sizeof(struct ext2_inode));
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| 93 | data->flags |= CHANNEL_HAS_INODE;
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| 94 | }
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| 95 | data->next = top_intern;
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| 96 | top_intern = data;
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| 97 | *name = data->name;
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| 98 | return 0;
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| 99 | }
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| 100 |
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| 101 | errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
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| 102 | char **name)
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| 103 | {
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| 104 | return ext2fs_inode_io_intern2(fs, ino, NULL, name);
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| 105 | }
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| 106 |
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| 107 |
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| 108 | static errcode_t inode_open(const char *name, int flags, io_channel *channel)
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| 109 | {
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| 110 | io_channel io = NULL;
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| 111 | struct inode_private_data *prev, *data = NULL;
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| 112 | errcode_t retval;
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| 113 | int open_flags;
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| 114 |
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| 115 | if (name == 0)
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| 116 | return EXT2_ET_BAD_DEVICE_NAME;
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| 117 |
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| 118 | for (data = top_intern, prev = NULL; data;
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| 119 | prev = data, data = data->next)
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| 120 | if (strcmp(name, data->name) == 0)
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| 121 | break;
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| 122 | if (!data)
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| 123 | return ENOENT;
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| 124 | if (prev)
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| 125 | prev->next = data->next;
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| 126 | else
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| 127 | top_intern = data->next;
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| 128 |
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| 129 | retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
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| 130 | if (retval)
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| 131 | goto cleanup;
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| 132 | memset(io, 0, sizeof(struct struct_io_channel));
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| 133 |
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| 134 | io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
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| 135 | io->manager = inode_io_manager;
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| 136 | retval = ext2fs_get_mem(strlen(name)+1, &io->name);
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| 137 | if (retval)
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| 138 | goto cleanup;
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| 139 |
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| 140 | strcpy(io->name, name);
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| 141 | io->private_data = data;
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| 142 | io->block_size = 1024;
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| 143 | io->read_error = 0;
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| 144 | io->write_error = 0;
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| 145 | io->refcount = 1;
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| 146 |
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| 147 | open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
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| 148 | retval = ext2fs_file_open2(data->fs, data->ino,
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| 149 | (data->flags & CHANNEL_HAS_INODE) ?
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| 150 | &data->inode : 0, open_flags,
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| 151 | &data->file);
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| 152 | if (retval)
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| 153 | goto cleanup;
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| 154 |
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| 155 | *channel = io;
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| 156 | return 0;
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| 157 |
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| 158 | cleanup:
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| 159 | if (data) {
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| 160 | ext2fs_free_mem(&data);
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| 161 | }
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| 162 | if (io)
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| 163 | ext2fs_free_mem(&io);
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| 164 | return retval;
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| 165 | }
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| 166 |
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| 167 | static errcode_t inode_close(io_channel channel)
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| 168 | {
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| 169 | struct inode_private_data *data;
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| 170 | errcode_t retval = 0;
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| 171 |
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| 172 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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| 173 | data = (struct inode_private_data *) channel->private_data;
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| 174 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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| 175 |
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| 176 | if (--channel->refcount > 0)
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| 177 | return 0;
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| 178 |
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| 179 | retval = ext2fs_file_close(data->file);
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| 180 |
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| 181 | ext2fs_free_mem(&channel->private_data);
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| 182 | if (channel->name)
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| 183 | ext2fs_free_mem(&channel->name);
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| 184 | ext2fs_free_mem(&channel);
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| 185 | return retval;
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| 186 | }
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| 187 |
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| 188 | static errcode_t inode_set_blksize(io_channel channel, int blksize)
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| 189 | {
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| 190 | struct inode_private_data *data;
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| 191 |
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| 192 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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| 193 | data = (struct inode_private_data *) channel->private_data;
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| 194 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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| 195 |
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| 196 | channel->block_size = blksize;
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| 197 | return 0;
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| 198 | }
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| 199 |
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| 200 |
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| 201 | static errcode_t inode_read_blk(io_channel channel, unsigned long block,
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| 202 | int count, void *buf)
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| 203 | {
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| 204 | struct inode_private_data *data;
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| 205 | errcode_t retval;
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| 206 |
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| 207 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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| 208 | data = (struct inode_private_data *) channel->private_data;
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| 209 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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| 210 |
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| 211 | if ((retval = ext2fs_file_lseek(data->file,
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| 212 | block * channel->block_size,
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| 213 | EXT2_SEEK_SET, 0)))
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| 214 | return retval;
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| 215 |
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| 216 | count = (count < 0) ? -count : (count * channel->block_size);
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| 217 |
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| 218 | return ext2fs_file_read(data->file, buf, count, 0);
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| 219 | }
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| 220 |
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| 221 | static errcode_t inode_write_blk(io_channel channel, unsigned long block,
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| 222 | int count, const void *buf)
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| 223 | {
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| 224 | struct inode_private_data *data;
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| 225 | errcode_t retval;
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| 226 |
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| 227 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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| 228 | data = (struct inode_private_data *) channel->private_data;
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| 229 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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| 230 |
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| 231 | if ((retval = ext2fs_file_lseek(data->file,
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| 232 | block * channel->block_size,
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| 233 | EXT2_SEEK_SET, 0)))
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| 234 | return retval;
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| 235 |
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| 236 | count = (count < 0) ? -count : (count * channel->block_size);
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| 237 |
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| 238 | return ext2fs_file_write(data->file, buf, count, 0);
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| 239 | }
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| 240 |
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| 241 | static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
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| 242 | int size, const void *buf)
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| 243 | {
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| 244 | struct inode_private_data *data;
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| 245 | errcode_t retval = 0;
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| 246 |
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| 247 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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| 248 | data = (struct inode_private_data *) channel->private_data;
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| 249 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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| 250 |
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| 251 | if ((retval = ext2fs_file_lseek(data->file, offset,
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| 252 | EXT2_SEEK_SET, 0)))
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| 253 | return retval;
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| 254 |
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| 255 | return ext2fs_file_write(data->file, buf, size, 0);
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| 256 | }
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| 257 |
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| 258 | /*
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| 259 | * Flush data buffers to disk.
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| 260 | */
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| 261 | static errcode_t inode_flush(io_channel channel)
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| 262 | {
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| 263 | struct inode_private_data *data;
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| 264 |
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| 265 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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| 266 | data = (struct inode_private_data *) channel->private_data;
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| 267 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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| 268 |
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| 269 | return ext2fs_file_flush(data->file);
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| 270 | }
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| 271 |
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