2 * fileio.c --- Simple file I/O routines
4 * Copyright (C) 1997 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
26 struct ext2_inode inode;
34 #define BMAP_BUFFER (file->buf + fs->blocksize)
36 errcode_t ext2fs_file_open2(ext2_filsys fs, ext2_ino_t ino,
37 struct ext2_inode *inode,
38 int flags, ext2_file_t *ret)
44 * Don't let caller create or open a file for writing if the
45 * filesystem is read-only.
47 if ((flags & (EXT2_FILE_WRITE | EXT2_FILE_CREATE)) &&
48 !(fs->flags & EXT2_FLAG_RW))
49 return EXT2_ET_RO_FILSYS;
51 retval = ext2fs_get_mem(sizeof(struct ext2_file), &file);
55 memset(file, 0, sizeof(struct ext2_file));
56 file->magic = EXT2_ET_MAGIC_EXT2_FILE;
59 file->flags = flags & EXT2_FILE_MASK;
62 memcpy(&file->inode, inode, sizeof(struct ext2_inode));
64 retval = ext2fs_read_inode(fs, ino, &file->inode);
69 retval = ext2fs_get_array(3, fs->blocksize, &file->buf);
78 ext2fs_free_mem(&file->buf);
79 ext2fs_free_mem(&file);
83 errcode_t ext2fs_file_open(ext2_filsys fs, ext2_ino_t ino,
84 int flags, ext2_file_t *ret)
86 return ext2fs_file_open2(fs, ino, NULL, flags, ret);
90 * This function returns the filesystem handle of a file from the structure
92 ext2_filsys ext2fs_file_get_fs(ext2_file_t file)
94 if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
100 * This function returns the pointer to the inode of a file from the structure
102 struct ext2_inode *ext2fs_file_get_inode(ext2_file_t file)
104 if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
109 /* This function returns the inode number from the structure */
110 ext2_ino_t ext2fs_file_get_inode_num(ext2_file_t file)
112 if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
118 * This function flushes the dirty block buffer out to disk if
121 errcode_t ext2fs_file_flush(ext2_file_t file)
126 EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
129 if (!(file->flags & EXT2_FILE_BUF_VALID) ||
130 !(file->flags & EXT2_FILE_BUF_DIRTY))
134 * OK, the physical block hasn't been allocated yet.
137 if (!file->physblock) {
138 retval = ext2fs_bmap2(fs, file->ino, &file->inode,
139 BMAP_BUFFER, file->ino ? BMAP_ALLOC : 0,
140 file->blockno, 0, &file->physblock);
145 retval = io_channel_write_blk(fs->io, file->physblock,
150 file->flags &= ~EXT2_FILE_BUF_DIRTY;
156 * This function synchronizes the file's block buffer and the current
157 * file position, possibly invalidating block buffer if necessary
159 static errcode_t sync_buffer_position(ext2_file_t file)
164 b = file->pos / file->fs->blocksize;
165 if (b != file->blockno) {
166 retval = ext2fs_file_flush(file);
169 file->flags &= ~EXT2_FILE_BUF_VALID;
176 * This function loads the file's block buffer with valid data from
177 * the disk as necessary.
179 * If dontfill is true, then skip initializing the buffer since we're
180 * going to be replacing its entire contents anyway. If set, then the
181 * function basically only sets file->physblock and EXT2_FILE_BUF_VALID
184 static errcode_t load_buffer(ext2_file_t file, int dontfill)
186 ext2_filsys fs = file->fs;
189 if (!(file->flags & EXT2_FILE_BUF_VALID)) {
190 retval = ext2fs_bmap2(fs, file->ino, &file->inode,
191 BMAP_BUFFER, 0, file->blockno, 0,
196 if (file->physblock) {
197 retval = io_channel_read_blk(fs->io,
203 memset(file->buf, 0, fs->blocksize);
205 file->flags |= EXT2_FILE_BUF_VALID;
211 errcode_t ext2fs_file_close(ext2_file_t file)
215 EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
217 retval = ext2fs_file_flush(file);
220 ext2fs_free_mem(&file->buf);
221 ext2fs_free_mem(&file);
227 errcode_t ext2fs_file_read(ext2_file_t file, void *buf,
228 unsigned int wanted, unsigned int *got)
231 errcode_t retval = 0;
232 unsigned int start, c, count = 0;
234 char *ptr = (char *) buf;
236 EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
239 while ((file->pos < EXT2_I_SIZE(&file->inode)) && (wanted > 0)) {
240 retval = sync_buffer_position(file);
243 retval = load_buffer(file, 0);
247 start = file->pos % fs->blocksize;
248 c = fs->blocksize - start;
251 left = EXT2_I_SIZE(&file->inode) - file->pos ;
255 memcpy(ptr, file->buf+start, c);
269 errcode_t ext2fs_file_write(ext2_file_t file, const void *buf,
270 unsigned int nbytes, unsigned int *written)
273 errcode_t retval = 0;
274 unsigned int start, c, count = 0;
275 const char *ptr = (const char *) buf;
277 EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
280 if (!(file->flags & EXT2_FILE_WRITE))
281 return EXT2_ET_FILE_RO;
284 retval = sync_buffer_position(file);
288 start = file->pos % fs->blocksize;
289 c = fs->blocksize - start;
294 * We only need to do a read-modify-update cycle if
295 * we're doing a partial write.
297 retval = load_buffer(file, (c == fs->blocksize));
301 file->flags |= EXT2_FILE_BUF_DIRTY;
302 memcpy(file->buf+start, ptr, c);
315 errcode_t ext2fs_file_llseek(ext2_file_t file, __u64 offset,
316 int whence, __u64 *ret_pos)
318 EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
320 if (whence == EXT2_SEEK_SET)
322 else if (whence == EXT2_SEEK_CUR)
324 else if (whence == EXT2_SEEK_END)
325 file->pos = EXT2_I_SIZE(&file->inode) + offset;
327 return EXT2_ET_INVALID_ARGUMENT;
330 *ret_pos = file->pos;
335 errcode_t ext2fs_file_lseek(ext2_file_t file, ext2_off_t offset,
336 int whence, ext2_off_t *ret_pos)
338 __u64 loffset, ret_loffset;
342 retval = ext2fs_file_llseek(file, loffset, whence, &ret_loffset);
344 *ret_pos = (ext2_off_t) ret_loffset;
350 * This function returns the size of the file, according to the inode
352 errcode_t ext2fs_file_get_lsize(ext2_file_t file, __u64 *ret_size)
354 if (file->magic != EXT2_ET_MAGIC_EXT2_FILE)
355 return EXT2_ET_MAGIC_EXT2_FILE;
356 *ret_size = EXT2_I_SIZE(&file->inode);
361 * This function returns the size of the file, according to the inode
363 ext2_off_t ext2fs_file_get_size(ext2_file_t file)
367 if (ext2fs_file_get_lsize(file, &size))
369 if ((size >> 32) != 0)
375 * This function sets the size of the file, truncating it if necessary
378 errcode_t ext2fs_file_set_size2(ext2_file_t file, ext2_off64_t size)
380 ext2_off64_t old_size;
382 blk64_t old_truncate, truncate_block;
384 EXT2_CHECK_MAGIC(file, EXT2_ET_MAGIC_EXT2_FILE);
386 truncate_block = ((size + file->fs->blocksize - 1) >>
387 EXT2_BLOCK_SIZE_BITS(file->fs->super)) + 1;
388 old_size = EXT2_I_SIZE(&file->inode);
389 old_truncate = ((old_size + file->fs->blocksize - 1) >>
390 EXT2_BLOCK_SIZE_BITS(file->fs->super)) + 1;
392 file->inode.i_size = size & 0xffffffff;
393 file->inode.i_size_high = (size >> 32);
395 retval = ext2fs_write_inode(file->fs, file->ino, &file->inode);
400 if (truncate_block >= old_truncate)
403 return ext2fs_punch(file->fs, file->ino, &file->inode, 0,
404 truncate_block, ~0ULL);
407 errcode_t ext2fs_file_set_size(ext2_file_t file, ext2_off_t size)
409 return ext2fs_file_set_size2(file, size);