Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * fs/libfs.c |
| 3 | * Library for filesystems writers. |
| 4 | */ |
| 5 | |
| 6 | #include <linux/module.h> |
| 7 | #include <linux/pagemap.h> |
| 8 | #include <linux/mount.h> |
| 9 | #include <linux/vfs.h> |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 10 | #include <linux/mutex.h> |
| 11 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <asm/uaccess.h> |
| 13 | |
| 14 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, |
| 15 | struct kstat *stat) |
| 16 | { |
| 17 | struct inode *inode = dentry->d_inode; |
| 18 | generic_fillattr(inode, stat); |
| 19 | stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9); |
| 20 | return 0; |
| 21 | } |
| 22 | |
| 23 | int simple_statfs(struct super_block *sb, struct kstatfs *buf) |
| 24 | { |
| 25 | buf->f_type = sb->s_magic; |
| 26 | buf->f_bsize = PAGE_CACHE_SIZE; |
| 27 | buf->f_namelen = NAME_MAX; |
| 28 | return 0; |
| 29 | } |
| 30 | |
| 31 | /* |
| 32 | * Retaining negative dentries for an in-memory filesystem just wastes |
| 33 | * memory and lookup time: arrange for them to be deleted immediately. |
| 34 | */ |
| 35 | static int simple_delete_dentry(struct dentry *dentry) |
| 36 | { |
| 37 | return 1; |
| 38 | } |
| 39 | |
| 40 | /* |
| 41 | * Lookup the data. This is trivial - if the dentry didn't already |
| 42 | * exist, we know it is negative. Set d_op to delete negative dentries. |
| 43 | */ |
| 44 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) |
| 45 | { |
| 46 | static struct dentry_operations simple_dentry_operations = { |
| 47 | .d_delete = simple_delete_dentry, |
| 48 | }; |
| 49 | |
| 50 | if (dentry->d_name.len > NAME_MAX) |
| 51 | return ERR_PTR(-ENAMETOOLONG); |
| 52 | dentry->d_op = &simple_dentry_operations; |
| 53 | d_add(dentry, NULL); |
| 54 | return NULL; |
| 55 | } |
| 56 | |
| 57 | int simple_sync_file(struct file * file, struct dentry *dentry, int datasync) |
| 58 | { |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | int dcache_dir_open(struct inode *inode, struct file *file) |
| 63 | { |
| 64 | static struct qstr cursor_name = {.len = 1, .name = "."}; |
| 65 | |
| 66 | file->private_data = d_alloc(file->f_dentry, &cursor_name); |
| 67 | |
| 68 | return file->private_data ? 0 : -ENOMEM; |
| 69 | } |
| 70 | |
| 71 | int dcache_dir_close(struct inode *inode, struct file *file) |
| 72 | { |
| 73 | dput(file->private_data); |
| 74 | return 0; |
| 75 | } |
| 76 | |
| 77 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin) |
| 78 | { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 79 | mutex_lock(&file->f_dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | switch (origin) { |
| 81 | case 1: |
| 82 | offset += file->f_pos; |
| 83 | case 0: |
| 84 | if (offset >= 0) |
| 85 | break; |
| 86 | default: |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 87 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 88 | return -EINVAL; |
| 89 | } |
| 90 | if (offset != file->f_pos) { |
| 91 | file->f_pos = offset; |
| 92 | if (file->f_pos >= 2) { |
| 93 | struct list_head *p; |
| 94 | struct dentry *cursor = file->private_data; |
| 95 | loff_t n = file->f_pos - 2; |
| 96 | |
| 97 | spin_lock(&dcache_lock); |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 98 | list_del(&cursor->d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | p = file->f_dentry->d_subdirs.next; |
| 100 | while (n && p != &file->f_dentry->d_subdirs) { |
| 101 | struct dentry *next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 102 | next = list_entry(p, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | if (!d_unhashed(next) && next->d_inode) |
| 104 | n--; |
| 105 | p = p->next; |
| 106 | } |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 107 | list_add_tail(&cursor->d_u.d_child, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | spin_unlock(&dcache_lock); |
| 109 | } |
| 110 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 111 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | return offset; |
| 113 | } |
| 114 | |
| 115 | /* Relationship between i_mode and the DT_xxx types */ |
| 116 | static inline unsigned char dt_type(struct inode *inode) |
| 117 | { |
| 118 | return (inode->i_mode >> 12) & 15; |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Directory is locked and all positive dentries in it are safe, since |
| 123 | * for ramfs-type trees they can't go away without unlink() or rmdir(), |
| 124 | * both impossible due to the lock on directory. |
| 125 | */ |
| 126 | |
| 127 | int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) |
| 128 | { |
| 129 | struct dentry *dentry = filp->f_dentry; |
| 130 | struct dentry *cursor = filp->private_data; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 131 | struct list_head *p, *q = &cursor->d_u.d_child; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | ino_t ino; |
| 133 | int i = filp->f_pos; |
| 134 | |
| 135 | switch (i) { |
| 136 | case 0: |
| 137 | ino = dentry->d_inode->i_ino; |
| 138 | if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) |
| 139 | break; |
| 140 | filp->f_pos++; |
| 141 | i++; |
| 142 | /* fallthrough */ |
| 143 | case 1: |
| 144 | ino = parent_ino(dentry); |
| 145 | if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) |
| 146 | break; |
| 147 | filp->f_pos++; |
| 148 | i++; |
| 149 | /* fallthrough */ |
| 150 | default: |
| 151 | spin_lock(&dcache_lock); |
| 152 | if (filp->f_pos == 2) { |
| 153 | list_del(q); |
| 154 | list_add(q, &dentry->d_subdirs); |
| 155 | } |
| 156 | for (p=q->next; p != &dentry->d_subdirs; p=p->next) { |
| 157 | struct dentry *next; |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 158 | next = list_entry(p, struct dentry, d_u.d_child); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | if (d_unhashed(next) || !next->d_inode) |
| 160 | continue; |
| 161 | |
| 162 | spin_unlock(&dcache_lock); |
| 163 | if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0) |
| 164 | return 0; |
| 165 | spin_lock(&dcache_lock); |
| 166 | /* next is still alive */ |
| 167 | list_del(q); |
| 168 | list_add(q, p); |
| 169 | p = q; |
| 170 | filp->f_pos++; |
| 171 | } |
| 172 | spin_unlock(&dcache_lock); |
| 173 | } |
| 174 | return 0; |
| 175 | } |
| 176 | |
| 177 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) |
| 178 | { |
| 179 | return -EISDIR; |
| 180 | } |
| 181 | |
Arjan van de Ven | 4b6f5d2 | 2006-03-28 01:56:42 -0800 | [diff] [blame] | 182 | const struct file_operations simple_dir_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | .open = dcache_dir_open, |
| 184 | .release = dcache_dir_close, |
| 185 | .llseek = dcache_dir_lseek, |
| 186 | .read = generic_read_dir, |
| 187 | .readdir = dcache_readdir, |
Hugh Dickins | 8ae0b77 | 2005-06-25 14:55:41 -0700 | [diff] [blame] | 188 | .fsync = simple_sync_file, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | }; |
| 190 | |
| 191 | struct inode_operations simple_dir_inode_operations = { |
| 192 | .lookup = simple_lookup, |
| 193 | }; |
| 194 | |
| 195 | /* |
| 196 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that |
| 197 | * will never be mountable) |
| 198 | */ |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame^] | 199 | int get_sb_pseudo(struct file_system_type *fs_type, char *name, |
| 200 | struct super_operations *ops, unsigned long magic, |
| 201 | struct vfsmount *mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | { |
| 203 | struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL); |
| 204 | static struct super_operations default_ops = {.statfs = simple_statfs}; |
| 205 | struct dentry *dentry; |
| 206 | struct inode *root; |
| 207 | struct qstr d_name = {.name = name, .len = strlen(name)}; |
| 208 | |
| 209 | if (IS_ERR(s)) |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame^] | 210 | return PTR_ERR(s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | |
| 212 | s->s_flags = MS_NOUSER; |
| 213 | s->s_maxbytes = ~0ULL; |
| 214 | s->s_blocksize = 1024; |
| 215 | s->s_blocksize_bits = 10; |
| 216 | s->s_magic = magic; |
| 217 | s->s_op = ops ? ops : &default_ops; |
| 218 | s->s_time_gran = 1; |
| 219 | root = new_inode(s); |
| 220 | if (!root) |
| 221 | goto Enomem; |
| 222 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
| 223 | root->i_uid = root->i_gid = 0; |
| 224 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
| 225 | dentry = d_alloc(NULL, &d_name); |
| 226 | if (!dentry) { |
| 227 | iput(root); |
| 228 | goto Enomem; |
| 229 | } |
| 230 | dentry->d_sb = s; |
| 231 | dentry->d_parent = dentry; |
| 232 | d_instantiate(dentry, root); |
| 233 | s->s_root = dentry; |
| 234 | s->s_flags |= MS_ACTIVE; |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame^] | 235 | return simple_set_mnt(mnt, s); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | |
| 237 | Enomem: |
| 238 | up_write(&s->s_umount); |
| 239 | deactivate_super(s); |
David Howells | 454e239 | 2006-06-23 02:02:57 -0700 | [diff] [blame^] | 240 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | } |
| 242 | |
| 243 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
| 244 | { |
| 245 | struct inode *inode = old_dentry->d_inode; |
| 246 | |
| 247 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| 248 | inode->i_nlink++; |
| 249 | atomic_inc(&inode->i_count); |
| 250 | dget(dentry); |
| 251 | d_instantiate(dentry, inode); |
| 252 | return 0; |
| 253 | } |
| 254 | |
| 255 | static inline int simple_positive(struct dentry *dentry) |
| 256 | { |
| 257 | return dentry->d_inode && !d_unhashed(dentry); |
| 258 | } |
| 259 | |
| 260 | int simple_empty(struct dentry *dentry) |
| 261 | { |
| 262 | struct dentry *child; |
| 263 | int ret = 0; |
| 264 | |
| 265 | spin_lock(&dcache_lock); |
Eric Dumazet | 5160ee6 | 2006-01-08 01:03:32 -0800 | [diff] [blame] | 266 | list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 267 | if (simple_positive(child)) |
| 268 | goto out; |
| 269 | ret = 1; |
| 270 | out: |
| 271 | spin_unlock(&dcache_lock); |
| 272 | return ret; |
| 273 | } |
| 274 | |
| 275 | int simple_unlink(struct inode *dir, struct dentry *dentry) |
| 276 | { |
| 277 | struct inode *inode = dentry->d_inode; |
| 278 | |
| 279 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
| 280 | inode->i_nlink--; |
| 281 | dput(dentry); |
| 282 | return 0; |
| 283 | } |
| 284 | |
| 285 | int simple_rmdir(struct inode *dir, struct dentry *dentry) |
| 286 | { |
| 287 | if (!simple_empty(dentry)) |
| 288 | return -ENOTEMPTY; |
| 289 | |
| 290 | dentry->d_inode->i_nlink--; |
| 291 | simple_unlink(dir, dentry); |
| 292 | dir->i_nlink--; |
| 293 | return 0; |
| 294 | } |
| 295 | |
| 296 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 297 | struct inode *new_dir, struct dentry *new_dentry) |
| 298 | { |
| 299 | struct inode *inode = old_dentry->d_inode; |
| 300 | int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode); |
| 301 | |
| 302 | if (!simple_empty(new_dentry)) |
| 303 | return -ENOTEMPTY; |
| 304 | |
| 305 | if (new_dentry->d_inode) { |
| 306 | simple_unlink(new_dir, new_dentry); |
| 307 | if (they_are_dirs) |
| 308 | old_dir->i_nlink--; |
| 309 | } else if (they_are_dirs) { |
| 310 | old_dir->i_nlink--; |
| 311 | new_dir->i_nlink++; |
| 312 | } |
| 313 | |
| 314 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = |
| 315 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 316 | |
| 317 | return 0; |
| 318 | } |
| 319 | |
| 320 | int simple_readpage(struct file *file, struct page *page) |
| 321 | { |
| 322 | void *kaddr; |
| 323 | |
| 324 | if (PageUptodate(page)) |
| 325 | goto out; |
| 326 | |
| 327 | kaddr = kmap_atomic(page, KM_USER0); |
| 328 | memset(kaddr, 0, PAGE_CACHE_SIZE); |
| 329 | kunmap_atomic(kaddr, KM_USER0); |
| 330 | flush_dcache_page(page); |
| 331 | SetPageUptodate(page); |
| 332 | out: |
| 333 | unlock_page(page); |
| 334 | return 0; |
| 335 | } |
| 336 | |
| 337 | int simple_prepare_write(struct file *file, struct page *page, |
| 338 | unsigned from, unsigned to) |
| 339 | { |
| 340 | if (!PageUptodate(page)) { |
| 341 | if (to - from != PAGE_CACHE_SIZE) { |
| 342 | void *kaddr = kmap_atomic(page, KM_USER0); |
| 343 | memset(kaddr, 0, from); |
| 344 | memset(kaddr + to, 0, PAGE_CACHE_SIZE - to); |
| 345 | flush_dcache_page(page); |
| 346 | kunmap_atomic(kaddr, KM_USER0); |
| 347 | } |
| 348 | SetPageUptodate(page); |
| 349 | } |
| 350 | return 0; |
| 351 | } |
| 352 | |
| 353 | int simple_commit_write(struct file *file, struct page *page, |
| 354 | unsigned offset, unsigned to) |
| 355 | { |
| 356 | struct inode *inode = page->mapping->host; |
| 357 | loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; |
| 358 | |
| 359 | /* |
| 360 | * No need to use i_size_read() here, the i_size |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 361 | * cannot change under us because we hold the i_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | */ |
| 363 | if (pos > inode->i_size) |
| 364 | i_size_write(inode, pos); |
| 365 | set_page_dirty(page); |
| 366 | return 0; |
| 367 | } |
| 368 | |
| 369 | int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files) |
| 370 | { |
| 371 | static struct super_operations s_ops = {.statfs = simple_statfs}; |
| 372 | struct inode *inode; |
| 373 | struct dentry *root; |
| 374 | struct dentry *dentry; |
| 375 | int i; |
| 376 | |
| 377 | s->s_blocksize = PAGE_CACHE_SIZE; |
| 378 | s->s_blocksize_bits = PAGE_CACHE_SHIFT; |
| 379 | s->s_magic = magic; |
| 380 | s->s_op = &s_ops; |
| 381 | s->s_time_gran = 1; |
| 382 | |
| 383 | inode = new_inode(s); |
| 384 | if (!inode) |
| 385 | return -ENOMEM; |
| 386 | inode->i_mode = S_IFDIR | 0755; |
| 387 | inode->i_uid = inode->i_gid = 0; |
| 388 | inode->i_blksize = PAGE_CACHE_SIZE; |
| 389 | inode->i_blocks = 0; |
| 390 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 391 | inode->i_op = &simple_dir_inode_operations; |
| 392 | inode->i_fop = &simple_dir_operations; |
Vincent Hanquez | 7656f32 | 2006-02-03 03:04:48 -0800 | [diff] [blame] | 393 | inode->i_nlink = 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | root = d_alloc_root(inode); |
| 395 | if (!root) { |
| 396 | iput(inode); |
| 397 | return -ENOMEM; |
| 398 | } |
| 399 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
| 400 | if (!files->name) |
| 401 | continue; |
| 402 | dentry = d_alloc_name(root, files->name); |
| 403 | if (!dentry) |
| 404 | goto out; |
| 405 | inode = new_inode(s); |
| 406 | if (!inode) |
| 407 | goto out; |
| 408 | inode->i_mode = S_IFREG | files->mode; |
| 409 | inode->i_uid = inode->i_gid = 0; |
| 410 | inode->i_blksize = PAGE_CACHE_SIZE; |
| 411 | inode->i_blocks = 0; |
| 412 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
| 413 | inode->i_fop = files->ops; |
| 414 | inode->i_ino = i; |
| 415 | d_add(dentry, inode); |
| 416 | } |
| 417 | s->s_root = root; |
| 418 | return 0; |
| 419 | out: |
| 420 | d_genocide(root); |
| 421 | dput(root); |
| 422 | return -ENOMEM; |
| 423 | } |
| 424 | |
| 425 | static DEFINE_SPINLOCK(pin_fs_lock); |
| 426 | |
| 427 | int simple_pin_fs(char *name, struct vfsmount **mount, int *count) |
| 428 | { |
| 429 | struct vfsmount *mnt = NULL; |
| 430 | spin_lock(&pin_fs_lock); |
| 431 | if (unlikely(!*mount)) { |
| 432 | spin_unlock(&pin_fs_lock); |
| 433 | mnt = do_kern_mount(name, 0, name, NULL); |
| 434 | if (IS_ERR(mnt)) |
| 435 | return PTR_ERR(mnt); |
| 436 | spin_lock(&pin_fs_lock); |
| 437 | if (!*mount) |
| 438 | *mount = mnt; |
| 439 | } |
| 440 | mntget(*mount); |
| 441 | ++*count; |
| 442 | spin_unlock(&pin_fs_lock); |
| 443 | mntput(mnt); |
| 444 | return 0; |
| 445 | } |
| 446 | |
| 447 | void simple_release_fs(struct vfsmount **mount, int *count) |
| 448 | { |
| 449 | struct vfsmount *mnt; |
| 450 | spin_lock(&pin_fs_lock); |
| 451 | mnt = *mount; |
| 452 | if (!--*count) |
| 453 | *mount = NULL; |
| 454 | spin_unlock(&pin_fs_lock); |
| 455 | mntput(mnt); |
| 456 | } |
| 457 | |
| 458 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
| 459 | const void *from, size_t available) |
| 460 | { |
| 461 | loff_t pos = *ppos; |
| 462 | if (pos < 0) |
| 463 | return -EINVAL; |
| 464 | if (pos >= available) |
| 465 | return 0; |
| 466 | if (count > available - pos) |
| 467 | count = available - pos; |
| 468 | if (copy_to_user(to, from + pos, count)) |
| 469 | return -EFAULT; |
| 470 | *ppos = pos + count; |
| 471 | return count; |
| 472 | } |
| 473 | |
| 474 | /* |
| 475 | * Transaction based IO. |
| 476 | * The file expects a single write which triggers the transaction, and then |
| 477 | * possibly a read which collects the result - which is stored in a |
| 478 | * file-local buffer. |
| 479 | */ |
| 480 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
| 481 | { |
| 482 | struct simple_transaction_argresp *ar; |
| 483 | static DEFINE_SPINLOCK(simple_transaction_lock); |
| 484 | |
| 485 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) |
| 486 | return ERR_PTR(-EFBIG); |
| 487 | |
| 488 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); |
| 489 | if (!ar) |
| 490 | return ERR_PTR(-ENOMEM); |
| 491 | |
| 492 | spin_lock(&simple_transaction_lock); |
| 493 | |
| 494 | /* only one write allowed per open */ |
| 495 | if (file->private_data) { |
| 496 | spin_unlock(&simple_transaction_lock); |
| 497 | free_page((unsigned long)ar); |
| 498 | return ERR_PTR(-EBUSY); |
| 499 | } |
| 500 | |
| 501 | file->private_data = ar; |
| 502 | |
| 503 | spin_unlock(&simple_transaction_lock); |
| 504 | |
| 505 | if (copy_from_user(ar->data, buf, size)) |
| 506 | return ERR_PTR(-EFAULT); |
| 507 | |
| 508 | return ar->data; |
| 509 | } |
| 510 | |
| 511 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) |
| 512 | { |
| 513 | struct simple_transaction_argresp *ar = file->private_data; |
| 514 | |
| 515 | if (!ar) |
| 516 | return 0; |
| 517 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); |
| 518 | } |
| 519 | |
| 520 | int simple_transaction_release(struct inode *inode, struct file *file) |
| 521 | { |
| 522 | free_page((unsigned long)file->private_data); |
| 523 | return 0; |
| 524 | } |
| 525 | |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 526 | /* Simple attribute files */ |
| 527 | |
| 528 | struct simple_attr { |
| 529 | u64 (*get)(void *); |
| 530 | void (*set)(void *, u64); |
| 531 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
| 532 | char set_buf[24]; |
| 533 | void *data; |
| 534 | const char *fmt; /* format for read operation */ |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 535 | struct mutex mutex; /* protects access to these buffers */ |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 536 | }; |
| 537 | |
| 538 | /* simple_attr_open is called by an actual attribute open file operation |
| 539 | * to set the attribute specific access operations. */ |
| 540 | int simple_attr_open(struct inode *inode, struct file *file, |
| 541 | u64 (*get)(void *), void (*set)(void *, u64), |
| 542 | const char *fmt) |
| 543 | { |
| 544 | struct simple_attr *attr; |
| 545 | |
| 546 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); |
| 547 | if (!attr) |
| 548 | return -ENOMEM; |
| 549 | |
| 550 | attr->get = get; |
| 551 | attr->set = set; |
| 552 | attr->data = inode->u.generic_ip; |
| 553 | attr->fmt = fmt; |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 554 | mutex_init(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 555 | |
| 556 | file->private_data = attr; |
| 557 | |
| 558 | return nonseekable_open(inode, file); |
| 559 | } |
| 560 | |
| 561 | int simple_attr_close(struct inode *inode, struct file *file) |
| 562 | { |
| 563 | kfree(file->private_data); |
| 564 | return 0; |
| 565 | } |
| 566 | |
| 567 | /* read from the buffer that is filled with the get function */ |
| 568 | ssize_t simple_attr_read(struct file *file, char __user *buf, |
| 569 | size_t len, loff_t *ppos) |
| 570 | { |
| 571 | struct simple_attr *attr; |
| 572 | size_t size; |
| 573 | ssize_t ret; |
| 574 | |
| 575 | attr = file->private_data; |
| 576 | |
| 577 | if (!attr->get) |
| 578 | return -EACCES; |
| 579 | |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 580 | mutex_lock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 581 | if (*ppos) /* continued read */ |
| 582 | size = strlen(attr->get_buf); |
| 583 | else /* first read */ |
| 584 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
| 585 | attr->fmt, |
| 586 | (unsigned long long)attr->get(attr->data)); |
| 587 | |
| 588 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 589 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 590 | return ret; |
| 591 | } |
| 592 | |
| 593 | /* interpret the buffer as a number to call the set function with */ |
| 594 | ssize_t simple_attr_write(struct file *file, const char __user *buf, |
| 595 | size_t len, loff_t *ppos) |
| 596 | { |
| 597 | struct simple_attr *attr; |
| 598 | u64 val; |
| 599 | size_t size; |
| 600 | ssize_t ret; |
| 601 | |
| 602 | attr = file->private_data; |
| 603 | |
| 604 | if (!attr->set) |
| 605 | return -EACCES; |
| 606 | |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 607 | mutex_lock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 608 | ret = -EFAULT; |
| 609 | size = min(sizeof(attr->set_buf) - 1, len); |
| 610 | if (copy_from_user(attr->set_buf, buf, size)) |
| 611 | goto out; |
| 612 | |
| 613 | ret = len; /* claim we got the whole input */ |
| 614 | attr->set_buf[size] = '\0'; |
| 615 | val = simple_strtol(attr->set_buf, NULL, 0); |
| 616 | attr->set(attr->data, val); |
| 617 | out: |
Ingo Molnar | 7cf34c7 | 2006-03-23 03:00:36 -0800 | [diff] [blame] | 618 | mutex_unlock(&attr->mutex); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 619 | return ret; |
| 620 | } |
| 621 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 622 | EXPORT_SYMBOL(dcache_dir_close); |
| 623 | EXPORT_SYMBOL(dcache_dir_lseek); |
| 624 | EXPORT_SYMBOL(dcache_dir_open); |
| 625 | EXPORT_SYMBOL(dcache_readdir); |
| 626 | EXPORT_SYMBOL(generic_read_dir); |
| 627 | EXPORT_SYMBOL(get_sb_pseudo); |
| 628 | EXPORT_SYMBOL(simple_commit_write); |
| 629 | EXPORT_SYMBOL(simple_dir_inode_operations); |
| 630 | EXPORT_SYMBOL(simple_dir_operations); |
| 631 | EXPORT_SYMBOL(simple_empty); |
| 632 | EXPORT_SYMBOL(d_alloc_name); |
| 633 | EXPORT_SYMBOL(simple_fill_super); |
| 634 | EXPORT_SYMBOL(simple_getattr); |
| 635 | EXPORT_SYMBOL(simple_link); |
| 636 | EXPORT_SYMBOL(simple_lookup); |
| 637 | EXPORT_SYMBOL(simple_pin_fs); |
| 638 | EXPORT_SYMBOL(simple_prepare_write); |
| 639 | EXPORT_SYMBOL(simple_readpage); |
| 640 | EXPORT_SYMBOL(simple_release_fs); |
| 641 | EXPORT_SYMBOL(simple_rename); |
| 642 | EXPORT_SYMBOL(simple_rmdir); |
| 643 | EXPORT_SYMBOL(simple_statfs); |
| 644 | EXPORT_SYMBOL(simple_sync_file); |
| 645 | EXPORT_SYMBOL(simple_unlink); |
| 646 | EXPORT_SYMBOL(simple_read_from_buffer); |
| 647 | EXPORT_SYMBOL(simple_transaction_get); |
| 648 | EXPORT_SYMBOL(simple_transaction_read); |
| 649 | EXPORT_SYMBOL(simple_transaction_release); |
Arnd Bergmann | acaefc2 | 2005-05-18 14:40:59 +0200 | [diff] [blame] | 650 | EXPORT_SYMBOL_GPL(simple_attr_open); |
| 651 | EXPORT_SYMBOL_GPL(simple_attr_close); |
| 652 | EXPORT_SYMBOL_GPL(simple_attr_read); |
| 653 | EXPORT_SYMBOL_GPL(simple_attr_write); |