1 /* vi: set sw=4 ts=4: */
3 * inode_io.c --- This is allows an inode in an ext2 filesystem image
4 * to be accessed via the I/O manager interface.
6 * Copyright (C) 2002 Theodore Ts'o.
9 * This file may be redistributed under the terms of the GNU Public
28 * For checking structure magic numbers...
31 #define EXT2_CHECK_MAGIC(struct, code) \
32 if ((struct)->magic != (code)) return (code)
34 struct inode_private_data {
40 struct ext2_inode inode;
42 struct inode_private_data *next;
45 #define CHANNEL_HAS_INODE 0x8000
47 static struct inode_private_data *top_intern;
48 static int ino_unique = 0;
50 static errcode_t inode_open(const char *name, int flags, io_channel *channel);
51 static errcode_t inode_close(io_channel channel);
52 static errcode_t inode_set_blksize(io_channel channel, int blksize);
53 static errcode_t inode_read_blk(io_channel channel, unsigned long block,
54 int count, void *data);
55 static errcode_t inode_write_blk(io_channel channel, unsigned long block,
56 int count, const void *data);
57 static errcode_t inode_flush(io_channel channel);
58 static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
59 int size, const void *data);
61 static struct struct_io_manager struct_inode_manager = {
62 EXT2_ET_MAGIC_IO_MANAGER,
73 io_manager inode_io_manager = &struct_inode_manager;
75 errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
76 struct ext2_inode *inode,
79 struct inode_private_data *data;
82 if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
85 data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
86 sprintf(data->name, "%u:%d", ino, ino_unique++);
92 memcpy(&data->inode, inode, sizeof(struct ext2_inode));
93 data->flags |= CHANNEL_HAS_INODE;
95 data->next = top_intern;
101 errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
104 return ext2fs_inode_io_intern2(fs, ino, NULL, name);
108 static errcode_t inode_open(const char *name, int flags, io_channel *channel)
110 io_channel io = NULL;
111 struct inode_private_data *prev, *data = NULL;
116 return EXT2_ET_BAD_DEVICE_NAME;
118 for (data = top_intern, prev = NULL; data;
119 prev = data, data = data->next)
120 if (strcmp(name, data->name) == 0)
125 prev->next = data->next;
127 top_intern = data->next;
129 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
132 memset(io, 0, sizeof(struct struct_io_channel));
134 io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
135 io->manager = inode_io_manager;
136 retval = ext2fs_get_mem(strlen(name)+1, &io->name);
140 strcpy(io->name, name);
141 io->private_data = data;
142 io->block_size = 1024;
147 open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
148 retval = ext2fs_file_open2(data->fs, data->ino,
149 (data->flags & CHANNEL_HAS_INODE) ?
150 &data->inode : 0, open_flags,
160 ext2fs_free_mem(&data);
163 ext2fs_free_mem(&io);
167 static errcode_t inode_close(io_channel channel)
169 struct inode_private_data *data;
170 errcode_t retval = 0;
172 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
173 data = (struct inode_private_data *) channel->private_data;
174 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
176 if (--channel->refcount > 0)
179 retval = ext2fs_file_close(data->file);
181 ext2fs_free_mem(&channel->private_data);
183 ext2fs_free_mem(&channel->name);
184 ext2fs_free_mem(&channel);
188 static errcode_t inode_set_blksize(io_channel channel, int blksize)
190 struct inode_private_data *data;
192 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
193 data = (struct inode_private_data *) channel->private_data;
194 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
196 channel->block_size = blksize;
201 static errcode_t inode_read_blk(io_channel channel, unsigned long block,
202 int count, void *buf)
204 struct inode_private_data *data;
207 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
208 data = (struct inode_private_data *) channel->private_data;
209 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
211 if ((retval = ext2fs_file_lseek(data->file,
212 block * channel->block_size,
216 count = (count < 0) ? -count : (count * channel->block_size);
218 return ext2fs_file_read(data->file, buf, count, 0);
221 static errcode_t inode_write_blk(io_channel channel, unsigned long block,
222 int count, const void *buf)
224 struct inode_private_data *data;
227 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
228 data = (struct inode_private_data *) channel->private_data;
229 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
231 if ((retval = ext2fs_file_lseek(data->file,
232 block * channel->block_size,
236 count = (count < 0) ? -count : (count * channel->block_size);
238 return ext2fs_file_write(data->file, buf, count, 0);
241 static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
242 int size, const void *buf)
244 struct inode_private_data *data;
245 errcode_t retval = 0;
247 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
248 data = (struct inode_private_data *) channel->private_data;
249 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
251 if ((retval = ext2fs_file_lseek(data->file, offset,
255 return ext2fs_file_write(data->file, buf, size, 0);
259 * Flush data buffers to disk.
261 static errcode_t inode_flush(io_channel channel)
263 struct inode_private_data *data;
265 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
266 data = (struct inode_private_data *) channel->private_data;
267 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
269 return ext2fs_file_flush(data->file);