2 * inode_io.c --- This is allows an inode in an ext2 filesystem image
3 * to be accessed via the I/O manager interface.
5 * Copyright (C) 2002 Theodore Ts'o.
8 * This file may be redistributed under the terms of the GNU Public
27 * For checking structure magic numbers...
30 #define EXT2_CHECK_MAGIC(struct, code) \
31 if ((struct)->magic != (code)) return (code)
33 struct inode_private_data {
39 struct ext2_inode inode;
41 struct inode_private_data *next;
44 #define CHANNEL_HAS_INODE 0x8000
46 static struct inode_private_data *top_intern;
47 static int ino_unique = 0;
49 static errcode_t inode_open(const char *name, int flags, io_channel *channel);
50 static errcode_t inode_close(io_channel channel);
51 static errcode_t inode_set_blksize(io_channel channel, int blksize);
52 static errcode_t inode_read_blk(io_channel channel, unsigned long block,
53 int count, void *data);
54 static errcode_t inode_write_blk(io_channel channel, unsigned long block,
55 int count, const void *data);
56 static errcode_t inode_flush(io_channel channel);
57 static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
58 int size, const void *data);
60 static struct struct_io_manager struct_inode_manager = {
61 EXT2_ET_MAGIC_IO_MANAGER,
72 io_manager inode_io_manager = &struct_inode_manager;
74 errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
75 struct ext2_inode *inode,
78 struct inode_private_data *data;
81 if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
84 data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
85 sprintf(data->name, "%u:%d", ino, ino_unique++);
91 memcpy(&data->inode, inode, sizeof(struct ext2_inode));
92 data->flags |= CHANNEL_HAS_INODE;
94 data->next = top_intern;
100 errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
103 return ext2fs_inode_io_intern2(fs, ino, NULL, name);
107 static errcode_t inode_open(const char *name, int flags, io_channel *channel)
109 io_channel io = NULL;
110 struct inode_private_data *prev, *data = NULL;
115 return EXT2_ET_BAD_DEVICE_NAME;
117 for (data = top_intern, prev = NULL; data;
118 prev = data, data = data->next)
119 if (strcmp(name, data->name) == 0)
124 prev->next = data->next;
126 top_intern = data->next;
128 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
131 memset(io, 0, sizeof(struct struct_io_channel));
133 io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
134 io->manager = inode_io_manager;
135 retval = ext2fs_get_mem(strlen(name)+1, &io->name);
139 strcpy(io->name, name);
140 io->private_data = data;
141 io->block_size = 1024;
146 open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
147 retval = ext2fs_file_open2(data->fs, data->ino,
148 (data->flags & CHANNEL_HAS_INODE) ?
149 &data->inode : 0, open_flags,
159 ext2fs_free_mem(&data);
162 ext2fs_free_mem(&io);
166 static errcode_t inode_close(io_channel channel)
168 struct inode_private_data *data;
169 errcode_t retval = 0;
171 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
172 data = (struct inode_private_data *) channel->private_data;
173 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
175 if (--channel->refcount > 0)
178 retval = ext2fs_file_close(data->file);
180 ext2fs_free_mem(&channel->private_data);
182 ext2fs_free_mem(&channel->name);
183 ext2fs_free_mem(&channel);
187 static errcode_t inode_set_blksize(io_channel channel, int blksize)
189 struct inode_private_data *data;
191 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
192 data = (struct inode_private_data *) channel->private_data;
193 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
195 channel->block_size = blksize;
200 static errcode_t inode_read_blk(io_channel channel, unsigned long block,
201 int count, void *buf)
203 struct inode_private_data *data;
206 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
207 data = (struct inode_private_data *) channel->private_data;
208 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
210 if ((retval = ext2fs_file_lseek(data->file,
211 block * channel->block_size,
215 count = (count < 0) ? -count : (count * channel->block_size);
217 return ext2fs_file_read(data->file, buf, count, 0);
220 static errcode_t inode_write_blk(io_channel channel, unsigned long block,
221 int count, const void *buf)
223 struct inode_private_data *data;
226 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
227 data = (struct inode_private_data *) channel->private_data;
228 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
230 if ((retval = ext2fs_file_lseek(data->file,
231 block * channel->block_size,
235 count = (count < 0) ? -count : (count * channel->block_size);
237 return ext2fs_file_write(data->file, buf, count, 0);
240 static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
241 int size, const void *buf)
243 struct inode_private_data *data;
244 errcode_t retval = 0;
246 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
247 data = (struct inode_private_data *) channel->private_data;
248 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
250 if ((retval = ext2fs_file_lseek(data->file, offset,
254 return ext2fs_file_write(data->file, buf, size, 0);
258 * Flush data buffers to disk.
260 static errcode_t inode_flush(io_channel channel)
262 struct inode_private_data *data;
264 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
265 data = (struct inode_private_data *) channel->private_data;
266 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
268 return ext2fs_file_flush(data->file);