]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/libfs.c | |
3 | * Library for filesystems writers. | |
4 | */ | |
5 | ||
ac13a829 | 6 | #include <linux/blkdev.h> |
630d9c47 | 7 | #include <linux/export.h> |
1da177e4 | 8 | #include <linux/pagemap.h> |
5a0e3ad6 | 9 | #include <linux/slab.h> |
5b825c3a | 10 | #include <linux/cred.h> |
1da177e4 LT |
11 | #include <linux/mount.h> |
12 | #include <linux/vfs.h> | |
7bb46a67 | 13 | #include <linux/quotaops.h> |
7cf34c76 | 14 | #include <linux/mutex.h> |
87dc800b | 15 | #include <linux/namei.h> |
2596110a | 16 | #include <linux/exportfs.h> |
d5aacad5 | 17 | #include <linux/writeback.h> |
ff01bb48 | 18 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
7cf34c76 | 19 | |
7c0f6ba6 | 20 | #include <linux/uaccess.h> |
1da177e4 | 21 | |
a4464dbc AV |
22 | #include "internal.h" |
23 | ||
a528d35e DH |
24 | int simple_getattr(const struct path *path, struct kstat *stat, |
25 | u32 request_mask, unsigned int query_flags) | |
1da177e4 | 26 | { |
a528d35e | 27 | struct inode *inode = d_inode(path->dentry); |
1da177e4 | 28 | generic_fillattr(inode, stat); |
09cbfeaf | 29 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
1da177e4 LT |
30 | return 0; |
31 | } | |
12f38872 | 32 | EXPORT_SYMBOL(simple_getattr); |
1da177e4 | 33 | |
726c3342 | 34 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 35 | { |
726c3342 | 36 | buf->f_type = dentry->d_sb->s_magic; |
09cbfeaf | 37 | buf->f_bsize = PAGE_SIZE; |
1da177e4 LT |
38 | buf->f_namelen = NAME_MAX; |
39 | return 0; | |
40 | } | |
12f38872 | 41 | EXPORT_SYMBOL(simple_statfs); |
1da177e4 LT |
42 | |
43 | /* | |
44 | * Retaining negative dentries for an in-memory filesystem just wastes | |
45 | * memory and lookup time: arrange for them to be deleted immediately. | |
46 | */ | |
b26d4cd3 | 47 | int always_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
48 | { |
49 | return 1; | |
50 | } | |
b26d4cd3 AV |
51 | EXPORT_SYMBOL(always_delete_dentry); |
52 | ||
53 | const struct dentry_operations simple_dentry_operations = { | |
54 | .d_delete = always_delete_dentry, | |
55 | }; | |
56 | EXPORT_SYMBOL(simple_dentry_operations); | |
1da177e4 LT |
57 | |
58 | /* | |
59 | * Lookup the data. This is trivial - if the dentry didn't already | |
60 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
61 | */ | |
00cd8dd3 | 62 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 | 63 | { |
1da177e4 LT |
64 | if (dentry->d_name.len > NAME_MAX) |
65 | return ERR_PTR(-ENAMETOOLONG); | |
74931da7 AV |
66 | if (!dentry->d_sb->s_d_op) |
67 | d_set_d_op(dentry, &simple_dentry_operations); | |
1da177e4 LT |
68 | d_add(dentry, NULL); |
69 | return NULL; | |
70 | } | |
12f38872 | 71 | EXPORT_SYMBOL(simple_lookup); |
1da177e4 | 72 | |
1da177e4 LT |
73 | int dcache_dir_open(struct inode *inode, struct file *file) |
74 | { | |
ba65dc5e | 75 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
1da177e4 LT |
76 | |
77 | return file->private_data ? 0 : -ENOMEM; | |
78 | } | |
12f38872 | 79 | EXPORT_SYMBOL(dcache_dir_open); |
1da177e4 LT |
80 | |
81 | int dcache_dir_close(struct inode *inode, struct file *file) | |
82 | { | |
83 | dput(file->private_data); | |
84 | return 0; | |
85 | } | |
12f38872 | 86 | EXPORT_SYMBOL(dcache_dir_close); |
1da177e4 | 87 | |
4f42c1b5 | 88 | /* parent is locked at least shared */ |
c3031c8b AV |
89 | /* |
90 | * Returns an element of siblings' list. | |
91 | * We are looking for <count>th positive after <p>; if | |
92 | * found, dentry is grabbed and passed to caller via *<res>. | |
93 | * If no such element exists, the anchor of list is returned | |
94 | * and *<res> is set to NULL. | |
95 | */ | |
96 | static struct list_head *scan_positives(struct dentry *cursor, | |
97 | struct list_head *p, | |
98 | loff_t count, | |
99 | struct dentry **res) | |
4f42c1b5 | 100 | { |
c3031c8b AV |
101 | struct dentry *dentry = cursor->d_parent, *found = NULL; |
102 | ||
103 | spin_lock(&dentry->d_lock); | |
104 | while ((p = p->next) != &dentry->d_subdirs) { | |
4f42c1b5 | 105 | struct dentry *d = list_entry(p, struct dentry, d_child); |
c3031c8b AV |
106 | // we must at least skip cursors, to avoid livelocks |
107 | if (d->d_flags & DCACHE_DENTRY_CURSOR) | |
108 | continue; | |
109 | if (simple_positive(d) && !--count) { | |
110 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
111 | if (simple_positive(d)) | |
112 | found = dget_dlock(d); | |
113 | spin_unlock(&d->d_lock); | |
114 | if (likely(found)) | |
115 | break; | |
116 | count = 1; | |
117 | } | |
118 | if (need_resched()) { | |
119 | list_move(&cursor->d_child, p); | |
120 | p = &cursor->d_child; | |
121 | spin_unlock(&dentry->d_lock); | |
122 | cond_resched(); | |
123 | spin_lock(&dentry->d_lock); | |
4f42c1b5 AV |
124 | } |
125 | } | |
c3031c8b AV |
126 | spin_unlock(&dentry->d_lock); |
127 | dput(*res); | |
128 | *res = found; | |
129 | return p; | |
4f42c1b5 AV |
130 | } |
131 | ||
965c8e59 | 132 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 133 | { |
2fd6b7f5 | 134 | struct dentry *dentry = file->f_path.dentry; |
965c8e59 | 135 | switch (whence) { |
1da177e4 LT |
136 | case 1: |
137 | offset += file->f_pos; | |
138 | case 0: | |
139 | if (offset >= 0) | |
140 | break; | |
141 | default: | |
1da177e4 LT |
142 | return -EINVAL; |
143 | } | |
144 | if (offset != file->f_pos) { | |
c3031c8b AV |
145 | struct dentry *cursor = file->private_data; |
146 | struct dentry *to = NULL; | |
147 | struct list_head *p; | |
148 | ||
1da177e4 | 149 | file->f_pos = offset; |
c3031c8b AV |
150 | inode_lock_shared(dentry->d_inode); |
151 | ||
152 | if (file->f_pos > 2) { | |
153 | p = scan_positives(cursor, &dentry->d_subdirs, | |
154 | file->f_pos - 2, &to); | |
155 | spin_lock(&dentry->d_lock); | |
156 | list_move(&cursor->d_child, p); | |
157 | spin_unlock(&dentry->d_lock); | |
158 | } else { | |
159 | spin_lock(&dentry->d_lock); | |
160 | list_del_init(&cursor->d_child); | |
161 | spin_unlock(&dentry->d_lock); | |
1da177e4 | 162 | } |
c3031c8b AV |
163 | |
164 | dput(to); | |
165 | ||
166 | inode_unlock_shared(dentry->d_inode); | |
1da177e4 | 167 | } |
1da177e4 LT |
168 | return offset; |
169 | } | |
12f38872 | 170 | EXPORT_SYMBOL(dcache_dir_lseek); |
1da177e4 LT |
171 | |
172 | /* Relationship between i_mode and the DT_xxx types */ | |
173 | static inline unsigned char dt_type(struct inode *inode) | |
174 | { | |
175 | return (inode->i_mode >> 12) & 15; | |
176 | } | |
177 | ||
178 | /* | |
179 | * Directory is locked and all positive dentries in it are safe, since | |
180 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
181 | * both impossible due to the lock on directory. | |
182 | */ | |
183 | ||
5f99f4e7 | 184 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 185 | { |
5f99f4e7 AV |
186 | struct dentry *dentry = file->f_path.dentry; |
187 | struct dentry *cursor = file->private_data; | |
c3031c8b AV |
188 | struct list_head *anchor = &dentry->d_subdirs; |
189 | struct dentry *next = NULL; | |
190 | struct list_head *p; | |
1da177e4 | 191 | |
5f99f4e7 AV |
192 | if (!dir_emit_dots(file, ctx)) |
193 | return 0; | |
5f99f4e7 | 194 | |
4f42c1b5 | 195 | if (ctx->pos == 2) |
c3031c8b AV |
196 | p = anchor; |
197 | else | |
198 | p = &cursor->d_child; | |
199 | ||
200 | while ((p = scan_positives(cursor, p, 1, &next)) != anchor) { | |
5f99f4e7 | 201 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
dea655c2 | 202 | d_inode(next)->i_ino, dt_type(d_inode(next)))) |
4f42c1b5 | 203 | break; |
5f99f4e7 | 204 | ctx->pos++; |
1da177e4 | 205 | } |
c3031c8b AV |
206 | spin_lock(&dentry->d_lock); |
207 | list_move_tail(&cursor->d_child, p); | |
208 | spin_unlock(&dentry->d_lock); | |
209 | dput(next); | |
210 | ||
1da177e4 LT |
211 | return 0; |
212 | } | |
12f38872 | 213 | EXPORT_SYMBOL(dcache_readdir); |
1da177e4 LT |
214 | |
215 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
216 | { | |
217 | return -EISDIR; | |
218 | } | |
12f38872 | 219 | EXPORT_SYMBOL(generic_read_dir); |
1da177e4 | 220 | |
4b6f5d20 | 221 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
222 | .open = dcache_dir_open, |
223 | .release = dcache_dir_close, | |
224 | .llseek = dcache_dir_lseek, | |
225 | .read = generic_read_dir, | |
4e82901c | 226 | .iterate_shared = dcache_readdir, |
1b061d92 | 227 | .fsync = noop_fsync, |
1da177e4 | 228 | }; |
12f38872 | 229 | EXPORT_SYMBOL(simple_dir_operations); |
1da177e4 | 230 | |
92e1d5be | 231 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
232 | .lookup = simple_lookup, |
233 | }; | |
12f38872 | 234 | EXPORT_SYMBOL(simple_dir_inode_operations); |
1da177e4 | 235 | |
759b9775 HD |
236 | static const struct super_operations simple_super_operations = { |
237 | .statfs = simple_statfs, | |
238 | }; | |
239 | ||
1da177e4 LT |
240 | /* |
241 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
242 | * will never be mountable) | |
243 | */ | |
bba0bd31 AG |
244 | struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name, |
245 | const struct super_operations *ops, const struct xattr_handler **xattr, | |
c74a1cbb | 246 | const struct dentry_operations *dops, unsigned long magic) |
1da177e4 | 247 | { |
9249e17f | 248 | struct super_block *s; |
1da177e4 LT |
249 | struct dentry *dentry; |
250 | struct inode *root; | |
26fe5750 | 251 | struct qstr d_name = QSTR_INIT(name, strlen(name)); |
1da177e4 | 252 | |
1751e8a6 | 253 | s = sget_userns(fs_type, NULL, set_anon_super, SB_KERNMOUNT|SB_NOUSER, |
75422726 | 254 | &init_user_ns, NULL); |
1da177e4 | 255 | if (IS_ERR(s)) |
51139ada | 256 | return ERR_CAST(s); |
1da177e4 | 257 | |
89a4eb4b | 258 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
259 | s->s_blocksize = PAGE_SIZE; |
260 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 261 | s->s_magic = magic; |
759b9775 | 262 | s->s_op = ops ? ops : &simple_super_operations; |
bba0bd31 | 263 | s->s_xattr = xattr; |
1da177e4 LT |
264 | s->s_time_gran = 1; |
265 | root = new_inode(s); | |
266 | if (!root) | |
267 | goto Enomem; | |
1a1c9bb4 JL |
268 | /* |
269 | * since this is the first inode, make it number 1. New inodes created | |
270 | * after this must take care not to collide with it (by passing | |
271 | * max_reserved of 1 to iunique). | |
272 | */ | |
273 | root->i_ino = 1; | |
1da177e4 | 274 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
078cd827 | 275 | root->i_atime = root->i_mtime = root->i_ctime = current_time(root); |
a4464dbc | 276 | dentry = __d_alloc(s, &d_name); |
1da177e4 LT |
277 | if (!dentry) { |
278 | iput(root); | |
279 | goto Enomem; | |
280 | } | |
1da177e4 LT |
281 | d_instantiate(dentry, root); |
282 | s->s_root = dentry; | |
c74a1cbb | 283 | s->s_d_op = dops; |
1751e8a6 | 284 | s->s_flags |= SB_ACTIVE; |
51139ada | 285 | return dget(s->s_root); |
1da177e4 LT |
286 | |
287 | Enomem: | |
6f5bbff9 | 288 | deactivate_locked_super(s); |
51139ada | 289 | return ERR_PTR(-ENOMEM); |
1da177e4 | 290 | } |
bba0bd31 | 291 | EXPORT_SYMBOL(mount_pseudo_xattr); |
1da177e4 | 292 | |
20955e89 SB |
293 | int simple_open(struct inode *inode, struct file *file) |
294 | { | |
295 | if (inode->i_private) | |
296 | file->private_data = inode->i_private; | |
297 | return 0; | |
298 | } | |
12f38872 | 299 | EXPORT_SYMBOL(simple_open); |
20955e89 | 300 | |
1da177e4 LT |
301 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
302 | { | |
dea655c2 | 303 | struct inode *inode = d_inode(old_dentry); |
1da177e4 | 304 | |
078cd827 | 305 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
d8c76e6f | 306 | inc_nlink(inode); |
7de9c6ee | 307 | ihold(inode); |
1da177e4 LT |
308 | dget(dentry); |
309 | d_instantiate(dentry, inode); | |
310 | return 0; | |
311 | } | |
12f38872 | 312 | EXPORT_SYMBOL(simple_link); |
1da177e4 | 313 | |
1da177e4 LT |
314 | int simple_empty(struct dentry *dentry) |
315 | { | |
316 | struct dentry *child; | |
317 | int ret = 0; | |
318 | ||
2fd6b7f5 | 319 | spin_lock(&dentry->d_lock); |
946e51f2 | 320 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
da502956 NP |
321 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
322 | if (simple_positive(child)) { | |
323 | spin_unlock(&child->d_lock); | |
1da177e4 | 324 | goto out; |
da502956 NP |
325 | } |
326 | spin_unlock(&child->d_lock); | |
327 | } | |
1da177e4 LT |
328 | ret = 1; |
329 | out: | |
2fd6b7f5 | 330 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
331 | return ret; |
332 | } | |
12f38872 | 333 | EXPORT_SYMBOL(simple_empty); |
1da177e4 LT |
334 | |
335 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
336 | { | |
dea655c2 | 337 | struct inode *inode = d_inode(dentry); |
1da177e4 | 338 | |
078cd827 | 339 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
9a53c3a7 | 340 | drop_nlink(inode); |
1da177e4 LT |
341 | dput(dentry); |
342 | return 0; | |
343 | } | |
12f38872 | 344 | EXPORT_SYMBOL(simple_unlink); |
1da177e4 LT |
345 | |
346 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
347 | { | |
348 | if (!simple_empty(dentry)) | |
349 | return -ENOTEMPTY; | |
350 | ||
dea655c2 | 351 | drop_nlink(d_inode(dentry)); |
1da177e4 | 352 | simple_unlink(dir, dentry); |
9a53c3a7 | 353 | drop_nlink(dir); |
1da177e4 LT |
354 | return 0; |
355 | } | |
12f38872 | 356 | EXPORT_SYMBOL(simple_rmdir); |
1da177e4 LT |
357 | |
358 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
e0e0be8a MS |
359 | struct inode *new_dir, struct dentry *new_dentry, |
360 | unsigned int flags) | |
1da177e4 | 361 | { |
dea655c2 | 362 | struct inode *inode = d_inode(old_dentry); |
e36cb0b8 | 363 | int they_are_dirs = d_is_dir(old_dentry); |
1da177e4 | 364 | |
e0e0be8a MS |
365 | if (flags & ~RENAME_NOREPLACE) |
366 | return -EINVAL; | |
367 | ||
1da177e4 LT |
368 | if (!simple_empty(new_dentry)) |
369 | return -ENOTEMPTY; | |
370 | ||
dea655c2 | 371 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 372 | simple_unlink(new_dir, new_dentry); |
841590ce | 373 | if (they_are_dirs) { |
dea655c2 | 374 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 375 | drop_nlink(old_dir); |
841590ce | 376 | } |
1da177e4 | 377 | } else if (they_are_dirs) { |
9a53c3a7 | 378 | drop_nlink(old_dir); |
d8c76e6f | 379 | inc_nlink(new_dir); |
1da177e4 LT |
380 | } |
381 | ||
382 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
078cd827 | 383 | new_dir->i_mtime = inode->i_ctime = current_time(old_dir); |
1da177e4 LT |
384 | |
385 | return 0; | |
386 | } | |
12f38872 | 387 | EXPORT_SYMBOL(simple_rename); |
1da177e4 | 388 | |
7bb46a67 | 389 | /** |
eef2380c | 390 | * simple_setattr - setattr for simple filesystem |
7bb46a67 | 391 | * @dentry: dentry |
392 | * @iattr: iattr structure | |
393 | * | |
394 | * Returns 0 on success, -error on failure. | |
395 | * | |
eef2380c CH |
396 | * simple_setattr is a simple ->setattr implementation without a proper |
397 | * implementation of size changes. | |
398 | * | |
399 | * It can either be used for in-memory filesystems or special files | |
400 | * on simple regular filesystems. Anything that needs to change on-disk | |
401 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 | 402 | */ |
403 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
404 | { | |
dea655c2 | 405 | struct inode *inode = d_inode(dentry); |
7bb46a67 | 406 | int error; |
407 | ||
31051c85 | 408 | error = setattr_prepare(dentry, iattr); |
7bb46a67 | 409 | if (error) |
410 | return error; | |
411 | ||
2c27c65e CH |
412 | if (iattr->ia_valid & ATTR_SIZE) |
413 | truncate_setsize(inode, iattr->ia_size); | |
6a1a90ad | 414 | setattr_copy(inode, iattr); |
eef2380c CH |
415 | mark_inode_dirty(inode); |
416 | return 0; | |
7bb46a67 | 417 | } |
418 | EXPORT_SYMBOL(simple_setattr); | |
419 | ||
1da177e4 LT |
420 | int simple_readpage(struct file *file, struct page *page) |
421 | { | |
c0d92cbc | 422 | clear_highpage(page); |
1da177e4 LT |
423 | flush_dcache_page(page); |
424 | SetPageUptodate(page); | |
1da177e4 LT |
425 | unlock_page(page); |
426 | return 0; | |
427 | } | |
12f38872 | 428 | EXPORT_SYMBOL(simple_readpage); |
1da177e4 | 429 | |
afddba49 NP |
430 | int simple_write_begin(struct file *file, struct address_space *mapping, |
431 | loff_t pos, unsigned len, unsigned flags, | |
432 | struct page **pagep, void **fsdata) | |
433 | { | |
434 | struct page *page; | |
435 | pgoff_t index; | |
afddba49 | 436 | |
09cbfeaf | 437 | index = pos >> PAGE_SHIFT; |
afddba49 | 438 | |
54566b2c | 439 | page = grab_cache_page_write_begin(mapping, index, flags); |
afddba49 NP |
440 | if (!page) |
441 | return -ENOMEM; | |
442 | ||
443 | *pagep = page; | |
444 | ||
09cbfeaf KS |
445 | if (!PageUptodate(page) && (len != PAGE_SIZE)) { |
446 | unsigned from = pos & (PAGE_SIZE - 1); | |
193cf4b9 | 447 | |
09cbfeaf | 448 | zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
193cf4b9 BH |
449 | } |
450 | return 0; | |
afddba49 | 451 | } |
12f38872 | 452 | EXPORT_SYMBOL(simple_write_begin); |
afddba49 | 453 | |
ad2a722f BH |
454 | /** |
455 | * simple_write_end - .write_end helper for non-block-device FSes | |
456 | * @available: See .write_end of address_space_operations | |
457 | * @file: " | |
458 | * @mapping: " | |
459 | * @pos: " | |
460 | * @len: " | |
461 | * @copied: " | |
462 | * @page: " | |
463 | * @fsdata: " | |
464 | * | |
465 | * simple_write_end does the minimum needed for updating a page after writing is | |
466 | * done. It has the same API signature as the .write_end of | |
467 | * address_space_operations vector. So it can just be set onto .write_end for | |
468 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
469 | * Block based filesystems should use generic_write_end(). | |
470 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
471 | * is not called, so a filesystem that actually does store data in .write_inode | |
472 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
473 | * case that i_size has changed. | |
04fff641 AV |
474 | * |
475 | * Use *ONLY* with simple_readpage() | |
ad2a722f | 476 | */ |
afddba49 NP |
477 | int simple_write_end(struct file *file, struct address_space *mapping, |
478 | loff_t pos, unsigned len, unsigned copied, | |
479 | struct page *page, void *fsdata) | |
480 | { | |
ad2a722f BH |
481 | struct inode *inode = page->mapping->host; |
482 | loff_t last_pos = pos + copied; | |
afddba49 NP |
483 | |
484 | /* zero the stale part of the page if we did a short copy */ | |
04fff641 AV |
485 | if (!PageUptodate(page)) { |
486 | if (copied < len) { | |
487 | unsigned from = pos & (PAGE_SIZE - 1); | |
afddba49 | 488 | |
04fff641 AV |
489 | zero_user(page, from + copied, len - copied); |
490 | } | |
ad2a722f | 491 | SetPageUptodate(page); |
04fff641 | 492 | } |
ad2a722f BH |
493 | /* |
494 | * No need to use i_size_read() here, the i_size | |
495 | * cannot change under us because we hold the i_mutex. | |
496 | */ | |
497 | if (last_pos > inode->i_size) | |
498 | i_size_write(inode, last_pos); | |
afddba49 | 499 | |
ad2a722f | 500 | set_page_dirty(page); |
afddba49 | 501 | unlock_page(page); |
09cbfeaf | 502 | put_page(page); |
afddba49 NP |
503 | |
504 | return copied; | |
505 | } | |
12f38872 | 506 | EXPORT_SYMBOL(simple_write_end); |
afddba49 | 507 | |
1a1c9bb4 JL |
508 | /* |
509 | * the inodes created here are not hashed. If you use iunique to generate | |
510 | * unique inode values later for this filesystem, then you must take care | |
511 | * to pass it an appropriate max_reserved value to avoid collisions. | |
512 | */ | |
7d683a09 | 513 | int simple_fill_super(struct super_block *s, unsigned long magic, |
cda37124 | 514 | const struct tree_descr *files) |
1da177e4 | 515 | { |
1da177e4 LT |
516 | struct inode *inode; |
517 | struct dentry *root; | |
518 | struct dentry *dentry; | |
519 | int i; | |
520 | ||
09cbfeaf KS |
521 | s->s_blocksize = PAGE_SIZE; |
522 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 523 | s->s_magic = magic; |
759b9775 | 524 | s->s_op = &simple_super_operations; |
1da177e4 LT |
525 | s->s_time_gran = 1; |
526 | ||
527 | inode = new_inode(s); | |
528 | if (!inode) | |
529 | return -ENOMEM; | |
1a1c9bb4 JL |
530 | /* |
531 | * because the root inode is 1, the files array must not contain an | |
532 | * entry at index 1 | |
533 | */ | |
534 | inode->i_ino = 1; | |
1da177e4 | 535 | inode->i_mode = S_IFDIR | 0755; |
078cd827 | 536 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
1da177e4 LT |
537 | inode->i_op = &simple_dir_inode_operations; |
538 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 539 | set_nlink(inode, 2); |
48fde701 AV |
540 | root = d_make_root(inode); |
541 | if (!root) | |
1da177e4 | 542 | return -ENOMEM; |
1da177e4 LT |
543 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
544 | if (!files->name) | |
545 | continue; | |
1a1c9bb4 JL |
546 | |
547 | /* warn if it tries to conflict with the root inode */ | |
548 | if (unlikely(i == 1)) | |
549 | printk(KERN_WARNING "%s: %s passed in a files array" | |
550 | "with an index of 1!\n", __func__, | |
551 | s->s_type->name); | |
552 | ||
1da177e4 LT |
553 | dentry = d_alloc_name(root, files->name); |
554 | if (!dentry) | |
555 | goto out; | |
556 | inode = new_inode(s); | |
32096ea1 KK |
557 | if (!inode) { |
558 | dput(dentry); | |
1da177e4 | 559 | goto out; |
32096ea1 | 560 | } |
1da177e4 | 561 | inode->i_mode = S_IFREG | files->mode; |
078cd827 | 562 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
1da177e4 LT |
563 | inode->i_fop = files->ops; |
564 | inode->i_ino = i; | |
565 | d_add(dentry, inode); | |
566 | } | |
567 | s->s_root = root; | |
568 | return 0; | |
569 | out: | |
570 | d_genocide(root); | |
640946f2 | 571 | shrink_dcache_parent(root); |
1da177e4 LT |
572 | dput(root); |
573 | return -ENOMEM; | |
574 | } | |
12f38872 | 575 | EXPORT_SYMBOL(simple_fill_super); |
1da177e4 LT |
576 | |
577 | static DEFINE_SPINLOCK(pin_fs_lock); | |
578 | ||
1f5ce9e9 | 579 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
580 | { |
581 | struct vfsmount *mnt = NULL; | |
582 | spin_lock(&pin_fs_lock); | |
583 | if (unlikely(!*mount)) { | |
584 | spin_unlock(&pin_fs_lock); | |
1751e8a6 | 585 | mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
586 | if (IS_ERR(mnt)) |
587 | return PTR_ERR(mnt); | |
588 | spin_lock(&pin_fs_lock); | |
589 | if (!*mount) | |
590 | *mount = mnt; | |
591 | } | |
592 | mntget(*mount); | |
593 | ++*count; | |
594 | spin_unlock(&pin_fs_lock); | |
595 | mntput(mnt); | |
596 | return 0; | |
597 | } | |
12f38872 | 598 | EXPORT_SYMBOL(simple_pin_fs); |
1da177e4 LT |
599 | |
600 | void simple_release_fs(struct vfsmount **mount, int *count) | |
601 | { | |
602 | struct vfsmount *mnt; | |
603 | spin_lock(&pin_fs_lock); | |
604 | mnt = *mount; | |
605 | if (!--*count) | |
606 | *mount = NULL; | |
607 | spin_unlock(&pin_fs_lock); | |
608 | mntput(mnt); | |
609 | } | |
12f38872 | 610 | EXPORT_SYMBOL(simple_release_fs); |
1da177e4 | 611 | |
6d1029b5 AM |
612 | /** |
613 | * simple_read_from_buffer - copy data from the buffer to user space | |
614 | * @to: the user space buffer to read to | |
615 | * @count: the maximum number of bytes to read | |
616 | * @ppos: the current position in the buffer | |
617 | * @from: the buffer to read from | |
618 | * @available: the size of the buffer | |
619 | * | |
620 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
621 | * buffer @from at offset @ppos into the user space address starting at @to. | |
622 | * | |
623 | * On success, the number of bytes read is returned and the offset @ppos is | |
624 | * advanced by this number, or negative value is returned on error. | |
625 | **/ | |
1da177e4 LT |
626 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
627 | const void *from, size_t available) | |
628 | { | |
629 | loff_t pos = *ppos; | |
14be2746 SR |
630 | size_t ret; |
631 | ||
1da177e4 LT |
632 | if (pos < 0) |
633 | return -EINVAL; | |
14be2746 | 634 | if (pos >= available || !count) |
1da177e4 LT |
635 | return 0; |
636 | if (count > available - pos) | |
637 | count = available - pos; | |
14be2746 SR |
638 | ret = copy_to_user(to, from + pos, count); |
639 | if (ret == count) | |
1da177e4 | 640 | return -EFAULT; |
14be2746 | 641 | count -= ret; |
1da177e4 LT |
642 | *ppos = pos + count; |
643 | return count; | |
644 | } | |
12f38872 | 645 | EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4 | 646 | |
6a727b43 JS |
647 | /** |
648 | * simple_write_to_buffer - copy data from user space to the buffer | |
649 | * @to: the buffer to write to | |
650 | * @available: the size of the buffer | |
651 | * @ppos: the current position in the buffer | |
652 | * @from: the user space buffer to read from | |
653 | * @count: the maximum number of bytes to read | |
654 | * | |
655 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
656 | * space address starting at @from into the buffer @to at offset @ppos. | |
657 | * | |
658 | * On success, the number of bytes written is returned and the offset @ppos is | |
659 | * advanced by this number, or negative value is returned on error. | |
660 | **/ | |
661 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
662 | const void __user *from, size_t count) | |
663 | { | |
664 | loff_t pos = *ppos; | |
665 | size_t res; | |
666 | ||
667 | if (pos < 0) | |
668 | return -EINVAL; | |
669 | if (pos >= available || !count) | |
670 | return 0; | |
671 | if (count > available - pos) | |
672 | count = available - pos; | |
673 | res = copy_from_user(to + pos, from, count); | |
674 | if (res == count) | |
675 | return -EFAULT; | |
676 | count -= res; | |
677 | *ppos = pos + count; | |
678 | return count; | |
679 | } | |
12f38872 | 680 | EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43 | 681 | |
6d1029b5 AM |
682 | /** |
683 | * memory_read_from_buffer - copy data from the buffer | |
684 | * @to: the kernel space buffer to read to | |
685 | * @count: the maximum number of bytes to read | |
686 | * @ppos: the current position in the buffer | |
687 | * @from: the buffer to read from | |
688 | * @available: the size of the buffer | |
689 | * | |
690 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
691 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
692 | * | |
693 | * On success, the number of bytes read is returned and the offset @ppos is | |
694 | * advanced by this number, or negative value is returned on error. | |
695 | **/ | |
93b07113 AM |
696 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
697 | const void *from, size_t available) | |
698 | { | |
699 | loff_t pos = *ppos; | |
700 | ||
701 | if (pos < 0) | |
702 | return -EINVAL; | |
703 | if (pos >= available) | |
704 | return 0; | |
705 | if (count > available - pos) | |
706 | count = available - pos; | |
707 | memcpy(to, from + pos, count); | |
708 | *ppos = pos + count; | |
709 | ||
710 | return count; | |
711 | } | |
12f38872 | 712 | EXPORT_SYMBOL(memory_read_from_buffer); |
93b07113 | 713 | |
1da177e4 LT |
714 | /* |
715 | * Transaction based IO. | |
716 | * The file expects a single write which triggers the transaction, and then | |
717 | * possibly a read which collects the result - which is stored in a | |
718 | * file-local buffer. | |
719 | */ | |
76791ab2 IM |
720 | |
721 | void simple_transaction_set(struct file *file, size_t n) | |
722 | { | |
723 | struct simple_transaction_argresp *ar = file->private_data; | |
724 | ||
725 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
726 | ||
727 | /* | |
728 | * The barrier ensures that ar->size will really remain zero until | |
729 | * ar->data is ready for reading. | |
730 | */ | |
731 | smp_mb(); | |
732 | ar->size = n; | |
733 | } | |
12f38872 | 734 | EXPORT_SYMBOL(simple_transaction_set); |
76791ab2 | 735 | |
1da177e4 LT |
736 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
737 | { | |
738 | struct simple_transaction_argresp *ar; | |
739 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
740 | ||
741 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
742 | return ERR_PTR(-EFBIG); | |
743 | ||
744 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
745 | if (!ar) | |
746 | return ERR_PTR(-ENOMEM); | |
747 | ||
748 | spin_lock(&simple_transaction_lock); | |
749 | ||
750 | /* only one write allowed per open */ | |
751 | if (file->private_data) { | |
752 | spin_unlock(&simple_transaction_lock); | |
753 | free_page((unsigned long)ar); | |
754 | return ERR_PTR(-EBUSY); | |
755 | } | |
756 | ||
757 | file->private_data = ar; | |
758 | ||
759 | spin_unlock(&simple_transaction_lock); | |
760 | ||
761 | if (copy_from_user(ar->data, buf, size)) | |
762 | return ERR_PTR(-EFAULT); | |
763 | ||
764 | return ar->data; | |
765 | } | |
12f38872 | 766 | EXPORT_SYMBOL(simple_transaction_get); |
1da177e4 LT |
767 | |
768 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
769 | { | |
770 | struct simple_transaction_argresp *ar = file->private_data; | |
771 | ||
772 | if (!ar) | |
773 | return 0; | |
774 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
775 | } | |
12f38872 | 776 | EXPORT_SYMBOL(simple_transaction_read); |
1da177e4 LT |
777 | |
778 | int simple_transaction_release(struct inode *inode, struct file *file) | |
779 | { | |
780 | free_page((unsigned long)file->private_data); | |
781 | return 0; | |
782 | } | |
12f38872 | 783 | EXPORT_SYMBOL(simple_transaction_release); |
1da177e4 | 784 | |
acaefc25 AB |
785 | /* Simple attribute files */ |
786 | ||
787 | struct simple_attr { | |
8b88b099 CH |
788 | int (*get)(void *, u64 *); |
789 | int (*set)(void *, u64); | |
acaefc25 AB |
790 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
791 | char set_buf[24]; | |
792 | void *data; | |
793 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 794 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
795 | }; |
796 | ||
797 | /* simple_attr_open is called by an actual attribute open file operation | |
798 | * to set the attribute specific access operations. */ | |
799 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 800 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
801 | const char *fmt) |
802 | { | |
803 | struct simple_attr *attr; | |
804 | ||
805 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
806 | if (!attr) | |
807 | return -ENOMEM; | |
808 | ||
809 | attr->get = get; | |
810 | attr->set = set; | |
8e18e294 | 811 | attr->data = inode->i_private; |
acaefc25 | 812 | attr->fmt = fmt; |
7cf34c76 | 813 | mutex_init(&attr->mutex); |
acaefc25 AB |
814 | |
815 | file->private_data = attr; | |
816 | ||
817 | return nonseekable_open(inode, file); | |
818 | } | |
12f38872 | 819 | EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25 | 820 | |
74bedc4d | 821 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
822 | { |
823 | kfree(file->private_data); | |
824 | return 0; | |
825 | } | |
12f38872 | 826 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25 AB |
827 | |
828 | /* read from the buffer that is filled with the get function */ | |
829 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
830 | size_t len, loff_t *ppos) | |
831 | { | |
832 | struct simple_attr *attr; | |
833 | size_t size; | |
834 | ssize_t ret; | |
835 | ||
836 | attr = file->private_data; | |
837 | ||
838 | if (!attr->get) | |
839 | return -EACCES; | |
840 | ||
9261303a CH |
841 | ret = mutex_lock_interruptible(&attr->mutex); |
842 | if (ret) | |
843 | return ret; | |
844 | ||
8b88b099 | 845 | if (*ppos) { /* continued read */ |
acaefc25 | 846 | size = strlen(attr->get_buf); |
8b88b099 CH |
847 | } else { /* first read */ |
848 | u64 val; | |
849 | ret = attr->get(attr->data, &val); | |
850 | if (ret) | |
851 | goto out; | |
852 | ||
acaefc25 | 853 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
854 | attr->fmt, (unsigned long long)val); |
855 | } | |
acaefc25 AB |
856 | |
857 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 858 | out: |
7cf34c76 | 859 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
860 | return ret; |
861 | } | |
12f38872 | 862 | EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25 AB |
863 | |
864 | /* interpret the buffer as a number to call the set function with */ | |
865 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
866 | size_t len, loff_t *ppos) | |
867 | { | |
868 | struct simple_attr *attr; | |
869 | u64 val; | |
870 | size_t size; | |
871 | ssize_t ret; | |
872 | ||
873 | attr = file->private_data; | |
acaefc25 AB |
874 | if (!attr->set) |
875 | return -EACCES; | |
876 | ||
9261303a CH |
877 | ret = mutex_lock_interruptible(&attr->mutex); |
878 | if (ret) | |
879 | return ret; | |
880 | ||
acaefc25 AB |
881 | ret = -EFAULT; |
882 | size = min(sizeof(attr->set_buf) - 1, len); | |
883 | if (copy_from_user(attr->set_buf, buf, size)) | |
884 | goto out; | |
885 | ||
acaefc25 | 886 | attr->set_buf[size] = '\0'; |
f7b88631 | 887 | val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee WF |
888 | ret = attr->set(attr->data, val); |
889 | if (ret == 0) | |
890 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 891 | out: |
7cf34c76 | 892 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
893 | return ret; |
894 | } | |
12f38872 | 895 | EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25 | 896 | |
2596110a CH |
897 | /** |
898 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
899 | * @sb: filesystem to do the file handle conversion on | |
900 | * @fid: file handle to convert | |
901 | * @fh_len: length of the file handle in bytes | |
902 | * @fh_type: type of file handle | |
903 | * @get_inode: filesystem callback to retrieve inode | |
904 | * | |
905 | * This function decodes @fid as long as it has one of the well-known | |
906 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
907 | * inode for the object specified in the file handle. | |
908 | */ | |
909 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
910 | int fh_len, int fh_type, struct inode *(*get_inode) | |
911 | (struct super_block *sb, u64 ino, u32 gen)) | |
912 | { | |
913 | struct inode *inode = NULL; | |
914 | ||
915 | if (fh_len < 2) | |
916 | return NULL; | |
917 | ||
918 | switch (fh_type) { | |
919 | case FILEID_INO32_GEN: | |
920 | case FILEID_INO32_GEN_PARENT: | |
921 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
922 | break; | |
923 | } | |
924 | ||
4ea3ada2 | 925 | return d_obtain_alias(inode); |
2596110a CH |
926 | } |
927 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
928 | ||
929 | /** | |
ca186830 | 930 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
931 | * @sb: filesystem to do the file handle conversion on |
932 | * @fid: file handle to convert | |
933 | * @fh_len: length of the file handle in bytes | |
934 | * @fh_type: type of file handle | |
935 | * @get_inode: filesystem callback to retrieve inode | |
936 | * | |
937 | * This function decodes @fid as long as it has one of the well-known | |
938 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
939 | * inode for the _parent_ object specified in the file handle if it | |
940 | * is specified in the file handle, or NULL otherwise. | |
941 | */ | |
942 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
943 | int fh_len, int fh_type, struct inode *(*get_inode) | |
944 | (struct super_block *sb, u64 ino, u32 gen)) | |
945 | { | |
946 | struct inode *inode = NULL; | |
947 | ||
948 | if (fh_len <= 2) | |
949 | return NULL; | |
950 | ||
951 | switch (fh_type) { | |
952 | case FILEID_INO32_GEN_PARENT: | |
953 | inode = get_inode(sb, fid->i32.parent_ino, | |
954 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
955 | break; | |
956 | } | |
957 | ||
4ea3ada2 | 958 | return d_obtain_alias(inode); |
2596110a CH |
959 | } |
960 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
961 | ||
1b061d92 | 962 | /** |
ac13a829 FF |
963 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
964 | * | |
1b061d92 | 965 | * @file: file to synchronize |
ac13a829 FF |
966 | * @start: start offset in bytes |
967 | * @end: end offset in bytes (inclusive) | |
1b061d92 CH |
968 | * @datasync: only synchronize essential metadata if true |
969 | * | |
970 | * This is a generic implementation of the fsync method for simple | |
971 | * filesystems which track all non-inode metadata in the buffers list | |
972 | * hanging off the address_space structure. | |
973 | */ | |
ac13a829 FF |
974 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
975 | int datasync) | |
d5aacad5 | 976 | { |
7ea80859 | 977 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
978 | int err; |
979 | int ret; | |
980 | ||
383aa543 | 981 | err = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
982 | if (err) |
983 | return err; | |
984 | ||
5955102c | 985 | inode_lock(inode); |
d5aacad5 | 986 | ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63 | 987 | if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a82 | 988 | goto out; |
d5aacad5 | 989 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 990 | goto out; |
d5aacad5 | 991 | |
c3765016 | 992 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
993 | if (ret == 0) |
994 | ret = err; | |
ac13a829 | 995 | |
02c24a82 | 996 | out: |
5955102c | 997 | inode_unlock(inode); |
383aa543 JL |
998 | /* check and advance again to catch errors after syncing out buffers */ |
999 | err = file_check_and_advance_wb_err(file); | |
1000 | if (ret == 0) | |
1001 | ret = err; | |
1002 | return ret; | |
d5aacad5 | 1003 | } |
ac13a829 FF |
1004 | EXPORT_SYMBOL(__generic_file_fsync); |
1005 | ||
1006 | /** | |
1007 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
1008 | * with flush | |
1009 | * @file: file to synchronize | |
1010 | * @start: start offset in bytes | |
1011 | * @end: end offset in bytes (inclusive) | |
1012 | * @datasync: only synchronize essential metadata if true | |
1013 | * | |
1014 | */ | |
1015 | ||
1016 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
1017 | int datasync) | |
1018 | { | |
1019 | struct inode *inode = file->f_mapping->host; | |
1020 | int err; | |
1021 | ||
1022 | err = __generic_file_fsync(file, start, end, datasync); | |
1023 | if (err) | |
1024 | return err; | |
1025 | return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); | |
1026 | } | |
1b061d92 CH |
1027 | EXPORT_SYMBOL(generic_file_fsync); |
1028 | ||
30ca22c7 PL |
1029 | /** |
1030 | * generic_check_addressable - Check addressability of file system | |
1031 | * @blocksize_bits: log of file system block size | |
1032 | * @num_blocks: number of blocks in file system | |
1033 | * | |
1034 | * Determine whether a file system with @num_blocks blocks (and a | |
1035 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
1036 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
1037 | */ | |
1038 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
1039 | { | |
1040 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef | 1041 | u64 last_fs_page = |
09cbfeaf | 1042 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c7 PL |
1043 | |
1044 | if (unlikely(num_blocks == 0)) | |
1045 | return 0; | |
1046 | ||
09cbfeaf | 1047 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c7 PL |
1048 | return -EINVAL; |
1049 | ||
a33f13ef JB |
1050 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
1051 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
1052 | return -EFBIG; |
1053 | } | |
1054 | return 0; | |
1055 | } | |
1056 | EXPORT_SYMBOL(generic_check_addressable); | |
1057 | ||
1b061d92 CH |
1058 | /* |
1059 | * No-op implementation of ->fsync for in-memory filesystems. | |
1060 | */ | |
02c24a82 | 1061 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
1062 | { |
1063 | return 0; | |
1064 | } | |
1b061d92 | 1065 | EXPORT_SYMBOL(noop_fsync); |
87dc800b | 1066 | |
fceef393 AV |
1067 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
1068 | void kfree_link(void *p) | |
87dc800b | 1069 | { |
fceef393 | 1070 | kfree(p); |
87dc800b | 1071 | } |
fceef393 | 1072 | EXPORT_SYMBOL(kfree_link); |
6987843f AV |
1073 | |
1074 | /* | |
1075 | * nop .set_page_dirty method so that people can use .page_mkwrite on | |
1076 | * anon inodes. | |
1077 | */ | |
1078 | static int anon_set_page_dirty(struct page *page) | |
1079 | { | |
1080 | return 0; | |
1081 | }; | |
1082 | ||
1083 | /* | |
1084 | * A single inode exists for all anon_inode files. Contrary to pipes, | |
1085 | * anon_inode inodes have no associated per-instance data, so we need | |
1086 | * only allocate one of them. | |
1087 | */ | |
1088 | struct inode *alloc_anon_inode(struct super_block *s) | |
1089 | { | |
1090 | static const struct address_space_operations anon_aops = { | |
1091 | .set_page_dirty = anon_set_page_dirty, | |
1092 | }; | |
1093 | struct inode *inode = new_inode_pseudo(s); | |
1094 | ||
1095 | if (!inode) | |
1096 | return ERR_PTR(-ENOMEM); | |
1097 | ||
1098 | inode->i_ino = get_next_ino(); | |
1099 | inode->i_mapping->a_ops = &anon_aops; | |
1100 | ||
1101 | /* | |
1102 | * Mark the inode dirty from the very beginning, | |
1103 | * that way it will never be moved to the dirty | |
1104 | * list because mark_inode_dirty() will think | |
1105 | * that it already _is_ on the dirty list. | |
1106 | */ | |
1107 | inode->i_state = I_DIRTY; | |
1108 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1109 | inode->i_uid = current_fsuid(); | |
1110 | inode->i_gid = current_fsgid(); | |
1111 | inode->i_flags |= S_PRIVATE; | |
078cd827 | 1112 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
6987843f AV |
1113 | return inode; |
1114 | } | |
1115 | EXPORT_SYMBOL(alloc_anon_inode); | |
1c994a09 JL |
1116 | |
1117 | /** | |
1118 | * simple_nosetlease - generic helper for prohibiting leases | |
1119 | * @filp: file pointer | |
1120 | * @arg: type of lease to obtain | |
1121 | * @flp: new lease supplied for insertion | |
e6f5c789 | 1122 | * @priv: private data for lm_setup operation |
1c994a09 JL |
1123 | * |
1124 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1125 | * All arguments are ignored and it just returns -EINVAL. | |
1126 | */ | |
1127 | int | |
e6f5c789 JL |
1128 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
1129 | void **priv) | |
1c994a09 JL |
1130 | { |
1131 | return -EINVAL; | |
1132 | } | |
1133 | EXPORT_SYMBOL(simple_nosetlease); | |
61ba64fc | 1134 | |
6b255391 | 1135 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393 | 1136 | struct delayed_call *done) |
61ba64fc | 1137 | { |
6b255391 | 1138 | return inode->i_link; |
61ba64fc | 1139 | } |
6b255391 | 1140 | EXPORT_SYMBOL(simple_get_link); |
61ba64fc AV |
1141 | |
1142 | const struct inode_operations simple_symlink_inode_operations = { | |
6b255391 | 1143 | .get_link = simple_get_link, |
61ba64fc AV |
1144 | }; |
1145 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
fbabfd0f EB |
1146 | |
1147 | /* | |
1148 | * Operations for a permanently empty directory. | |
1149 | */ | |
1150 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1151 | { | |
1152 | return ERR_PTR(-ENOENT); | |
1153 | } | |
1154 | ||
a528d35e DH |
1155 | static int empty_dir_getattr(const struct path *path, struct kstat *stat, |
1156 | u32 request_mask, unsigned int query_flags) | |
fbabfd0f | 1157 | { |
a528d35e | 1158 | struct inode *inode = d_inode(path->dentry); |
fbabfd0f EB |
1159 | generic_fillattr(inode, stat); |
1160 | return 0; | |
1161 | } | |
1162 | ||
1163 | static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) | |
1164 | { | |
1165 | return -EPERM; | |
1166 | } | |
1167 | ||
fbabfd0f EB |
1168 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
1169 | { | |
1170 | return -EOPNOTSUPP; | |
1171 | } | |
1172 | ||
1173 | static const struct inode_operations empty_dir_inode_operations = { | |
1174 | .lookup = empty_dir_lookup, | |
1175 | .permission = generic_permission, | |
1176 | .setattr = empty_dir_setattr, | |
1177 | .getattr = empty_dir_getattr, | |
fbabfd0f EB |
1178 | .listxattr = empty_dir_listxattr, |
1179 | }; | |
1180 | ||
1181 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1182 | { | |
1183 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1184 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1185 | } | |
1186 | ||
1187 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1188 | { | |
1189 | dir_emit_dots(file, ctx); | |
1190 | return 0; | |
1191 | } | |
1192 | ||
1193 | static const struct file_operations empty_dir_operations = { | |
1194 | .llseek = empty_dir_llseek, | |
1195 | .read = generic_read_dir, | |
c51da20c | 1196 | .iterate_shared = empty_dir_readdir, |
fbabfd0f EB |
1197 | .fsync = noop_fsync, |
1198 | }; | |
1199 | ||
1200 | ||
1201 | void make_empty_dir_inode(struct inode *inode) | |
1202 | { | |
1203 | set_nlink(inode, 2); | |
1204 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1205 | inode->i_uid = GLOBAL_ROOT_UID; | |
1206 | inode->i_gid = GLOBAL_ROOT_GID; | |
1207 | inode->i_rdev = 0; | |
4b75de86 | 1208 | inode->i_size = 0; |
fbabfd0f EB |
1209 | inode->i_blkbits = PAGE_SHIFT; |
1210 | inode->i_blocks = 0; | |
1211 | ||
1212 | inode->i_op = &empty_dir_inode_operations; | |
f5c24438 | 1213 | inode->i_opflags &= ~IOP_XATTR; |
fbabfd0f EB |
1214 | inode->i_fop = &empty_dir_operations; |
1215 | } | |
1216 | ||
1217 | bool is_empty_dir_inode(struct inode *inode) | |
1218 | { | |
1219 | return (inode->i_fop == &empty_dir_operations) && | |
1220 | (inode->i_op == &empty_dir_inode_operations); | |
1221 | } |