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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/inode.c | |
3 | * | |
4 | * (C) 1997 Linus Torvalds | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/fs.h> |
8 | #include <linux/mm.h> | |
9 | #include <linux/dcache.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/quotaops.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/writeback.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/backing-dev.h> | |
16 | #include <linux/wait.h> | |
17 | #include <linux/hash.h> | |
18 | #include <linux/swap.h> | |
19 | #include <linux/security.h> | |
6146f0d5 | 20 | #include <linux/ima.h> |
1da177e4 LT |
21 | #include <linux/pagemap.h> |
22 | #include <linux/cdev.h> | |
23 | #include <linux/bootmem.h> | |
0eeca283 | 24 | #include <linux/inotify.h> |
3be25f49 | 25 | #include <linux/fsnotify.h> |
fc33a7bb | 26 | #include <linux/mount.h> |
efaee192 | 27 | #include <linux/async.h> |
f19d4a8f | 28 | #include <linux/posix_acl.h> |
1da177e4 LT |
29 | |
30 | /* | |
31 | * This is needed for the following functions: | |
32 | * - inode_has_buffers | |
33 | * - invalidate_inode_buffers | |
1da177e4 LT |
34 | * - invalidate_bdev |
35 | * | |
36 | * FIXME: remove all knowledge of the buffer layer from this file | |
37 | */ | |
38 | #include <linux/buffer_head.h> | |
39 | ||
40 | /* | |
41 | * New inode.c implementation. | |
42 | * | |
43 | * This implementation has the basic premise of trying | |
44 | * to be extremely low-overhead and SMP-safe, yet be | |
45 | * simple enough to be "obviously correct". | |
46 | * | |
47 | * Famous last words. | |
48 | */ | |
49 | ||
50 | /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */ | |
51 | ||
52 | /* #define INODE_PARANOIA 1 */ | |
53 | /* #define INODE_DEBUG 1 */ | |
54 | ||
55 | /* | |
56 | * Inode lookup is no longer as critical as it used to be: | |
57 | * most of the lookups are going to be through the dcache. | |
58 | */ | |
59 | #define I_HASHBITS i_hash_shift | |
60 | #define I_HASHMASK i_hash_mask | |
61 | ||
fa3536cc ED |
62 | static unsigned int i_hash_mask __read_mostly; |
63 | static unsigned int i_hash_shift __read_mostly; | |
1da177e4 LT |
64 | |
65 | /* | |
66 | * Each inode can be on two separate lists. One is | |
67 | * the hash list of the inode, used for lookups. The | |
68 | * other linked list is the "type" list: | |
69 | * "in_use" - valid inode, i_count > 0, i_nlink > 0 | |
70 | * "dirty" - as "in_use" but also dirty | |
71 | * "unused" - valid inode, i_count = 0 | |
72 | * | |
73 | * A "dirty" list is maintained for each super block, | |
74 | * allowing for low-overhead inode sync() operations. | |
75 | */ | |
76 | ||
77 | LIST_HEAD(inode_in_use); | |
78 | LIST_HEAD(inode_unused); | |
fa3536cc | 79 | static struct hlist_head *inode_hashtable __read_mostly; |
1da177e4 LT |
80 | |
81 | /* | |
82 | * A simple spinlock to protect the list manipulations. | |
83 | * | |
84 | * NOTE! You also have to own the lock if you change | |
85 | * the i_state of an inode while it is in use.. | |
86 | */ | |
87 | DEFINE_SPINLOCK(inode_lock); | |
88 | ||
89 | /* | |
f24075bd | 90 | * iprune_mutex provides exclusion between the kswapd or try_to_free_pages |
1da177e4 LT |
91 | * icache shrinking path, and the umount path. Without this exclusion, |
92 | * by the time prune_icache calls iput for the inode whose pages it has | |
93 | * been invalidating, or by the time it calls clear_inode & destroy_inode | |
94 | * from its final dispose_list, the struct super_block they refer to | |
95 | * (for inode->i_sb->s_op) may already have been freed and reused. | |
96 | */ | |
bdfc3266 | 97 | static DEFINE_MUTEX(iprune_mutex); |
1da177e4 LT |
98 | |
99 | /* | |
100 | * Statistics gathering.. | |
101 | */ | |
102 | struct inodes_stat_t inodes_stat; | |
103 | ||
6b3304b5 | 104 | static struct kmem_cache *inode_cachep __read_mostly; |
1da177e4 | 105 | |
1c0eeaf5 JE |
106 | static void wake_up_inode(struct inode *inode) |
107 | { | |
108 | /* | |
109 | * Prevent speculative execution through spin_unlock(&inode_lock); | |
110 | */ | |
111 | smp_mb(); | |
112 | wake_up_bit(&inode->i_state, __I_LOCK); | |
113 | } | |
114 | ||
2cb1599f DC |
115 | /** |
116 | * inode_init_always - perform inode structure intialisation | |
0bc02f3f RD |
117 | * @sb: superblock inode belongs to |
118 | * @inode: inode to initialise | |
2cb1599f DC |
119 | * |
120 | * These are initializations that need to be done on every inode | |
121 | * allocation as the fields are not initialised by slab allocation. | |
122 | */ | |
123 | struct inode *inode_init_always(struct super_block *sb, struct inode *inode) | |
1da177e4 | 124 | { |
f5e54d6e | 125 | static const struct address_space_operations empty_aops; |
1da177e4 | 126 | static struct inode_operations empty_iops; |
99ac48f5 | 127 | static const struct file_operations empty_fops; |
1da177e4 | 128 | |
6b3304b5 | 129 | struct address_space *const mapping = &inode->i_data; |
2cb1599f DC |
130 | |
131 | inode->i_sb = sb; | |
132 | inode->i_blkbits = sb->s_blocksize_bits; | |
133 | inode->i_flags = 0; | |
134 | atomic_set(&inode->i_count, 1); | |
135 | inode->i_op = &empty_iops; | |
136 | inode->i_fop = &empty_fops; | |
137 | inode->i_nlink = 1; | |
56ff5efa AV |
138 | inode->i_uid = 0; |
139 | inode->i_gid = 0; | |
2cb1599f DC |
140 | atomic_set(&inode->i_writecount, 0); |
141 | inode->i_size = 0; | |
142 | inode->i_blocks = 0; | |
143 | inode->i_bytes = 0; | |
144 | inode->i_generation = 0; | |
1da177e4 | 145 | #ifdef CONFIG_QUOTA |
2cb1599f | 146 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
1da177e4 | 147 | #endif |
2cb1599f DC |
148 | inode->i_pipe = NULL; |
149 | inode->i_bdev = NULL; | |
150 | inode->i_cdev = NULL; | |
151 | inode->i_rdev = 0; | |
152 | inode->dirtied_when = 0; | |
6146f0d5 MZ |
153 | |
154 | if (security_inode_alloc(inode)) | |
155 | goto out_free_inode; | |
156 | ||
157 | /* allocate and initialize an i_integrity */ | |
158 | if (ima_inode_alloc(inode)) | |
159 | goto out_free_security; | |
2cb1599f DC |
160 | |
161 | spin_lock_init(&inode->i_lock); | |
162 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); | |
163 | ||
164 | mutex_init(&inode->i_mutex); | |
165 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); | |
166 | ||
167 | init_rwsem(&inode->i_alloc_sem); | |
168 | lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); | |
169 | ||
170 | mapping->a_ops = &empty_aops; | |
171 | mapping->host = inode; | |
172 | mapping->flags = 0; | |
3c1d4378 | 173 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
2cb1599f DC |
174 | mapping->assoc_mapping = NULL; |
175 | mapping->backing_dev_info = &default_backing_dev_info; | |
176 | mapping->writeback_index = 0; | |
177 | ||
178 | /* | |
179 | * If the block_device provides a backing_dev_info for client | |
180 | * inodes then use that. Otherwise the inode share the bdev's | |
181 | * backing_dev_info. | |
182 | */ | |
183 | if (sb->s_bdev) { | |
184 | struct backing_dev_info *bdi; | |
185 | ||
186 | bdi = sb->s_bdev->bd_inode_backing_dev_info; | |
187 | if (!bdi) | |
188 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; | |
189 | mapping->backing_dev_info = bdi; | |
190 | } | |
191 | inode->i_private = NULL; | |
192 | inode->i_mapping = mapping; | |
f19d4a8f AV |
193 | #ifdef CONFIG_FS_POSIX_ACL |
194 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; | |
195 | #endif | |
2cb1599f | 196 | |
3be25f49 EP |
197 | #ifdef CONFIG_FSNOTIFY |
198 | inode->i_fsnotify_mask = 0; | |
199 | #endif | |
200 | ||
1da177e4 | 201 | return inode; |
6146f0d5 MZ |
202 | |
203 | out_free_security: | |
204 | security_inode_free(inode); | |
205 | out_free_inode: | |
206 | if (inode->i_sb->s_op->destroy_inode) | |
207 | inode->i_sb->s_op->destroy_inode(inode); | |
208 | else | |
209 | kmem_cache_free(inode_cachep, (inode)); | |
210 | return NULL; | |
1da177e4 | 211 | } |
2cb1599f DC |
212 | EXPORT_SYMBOL(inode_init_always); |
213 | ||
214 | static struct inode *alloc_inode(struct super_block *sb) | |
215 | { | |
216 | struct inode *inode; | |
217 | ||
218 | if (sb->s_op->alloc_inode) | |
219 | inode = sb->s_op->alloc_inode(sb); | |
220 | else | |
221 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); | |
222 | ||
223 | if (inode) | |
224 | return inode_init_always(sb, inode); | |
225 | return NULL; | |
226 | } | |
1da177e4 | 227 | |
6b3304b5 | 228 | void destroy_inode(struct inode *inode) |
1da177e4 | 229 | { |
b7542f8c | 230 | BUG_ON(inode_has_buffers(inode)); |
f07502da | 231 | ima_inode_free(inode); |
1da177e4 | 232 | security_inode_free(inode); |
3be25f49 | 233 | fsnotify_inode_delete(inode); |
f19d4a8f AV |
234 | #ifdef CONFIG_FS_POSIX_ACL |
235 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) | |
236 | posix_acl_release(inode->i_acl); | |
237 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) | |
238 | posix_acl_release(inode->i_default_acl); | |
239 | #endif | |
1da177e4 LT |
240 | if (inode->i_sb->s_op->destroy_inode) |
241 | inode->i_sb->s_op->destroy_inode(inode); | |
242 | else | |
243 | kmem_cache_free(inode_cachep, (inode)); | |
244 | } | |
087e3b04 | 245 | EXPORT_SYMBOL(destroy_inode); |
1da177e4 LT |
246 | |
247 | ||
248 | /* | |
249 | * These are initializations that only need to be done | |
250 | * once, because the fields are idempotent across use | |
251 | * of the inode, so let the slab aware of that. | |
252 | */ | |
253 | void inode_init_once(struct inode *inode) | |
254 | { | |
255 | memset(inode, 0, sizeof(*inode)); | |
256 | INIT_HLIST_NODE(&inode->i_hash); | |
257 | INIT_LIST_HEAD(&inode->i_dentry); | |
258 | INIT_LIST_HEAD(&inode->i_devices); | |
1da177e4 | 259 | INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); |
19fd6231 | 260 | spin_lock_init(&inode->i_data.tree_lock); |
1da177e4 LT |
261 | spin_lock_init(&inode->i_data.i_mmap_lock); |
262 | INIT_LIST_HEAD(&inode->i_data.private_list); | |
263 | spin_lock_init(&inode->i_data.private_lock); | |
264 | INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap); | |
265 | INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear); | |
1da177e4 | 266 | i_size_ordered_init(inode); |
0eeca283 RL |
267 | #ifdef CONFIG_INOTIFY |
268 | INIT_LIST_HEAD(&inode->inotify_watches); | |
d4f9af9d | 269 | mutex_init(&inode->inotify_mutex); |
0eeca283 | 270 | #endif |
3be25f49 EP |
271 | #ifdef CONFIG_FSNOTIFY |
272 | INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries); | |
273 | #endif | |
1da177e4 | 274 | } |
1da177e4 LT |
275 | EXPORT_SYMBOL(inode_init_once); |
276 | ||
51cc5068 | 277 | static void init_once(void *foo) |
1da177e4 | 278 | { |
6b3304b5 | 279 | struct inode *inode = (struct inode *) foo; |
1da177e4 | 280 | |
a35afb83 | 281 | inode_init_once(inode); |
1da177e4 LT |
282 | } |
283 | ||
284 | /* | |
285 | * inode_lock must be held | |
286 | */ | |
6b3304b5 | 287 | void __iget(struct inode *inode) |
1da177e4 LT |
288 | { |
289 | if (atomic_read(&inode->i_count)) { | |
290 | atomic_inc(&inode->i_count); | |
291 | return; | |
292 | } | |
293 | atomic_inc(&inode->i_count); | |
1c0eeaf5 | 294 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1da177e4 LT |
295 | list_move(&inode->i_list, &inode_in_use); |
296 | inodes_stat.nr_unused--; | |
297 | } | |
298 | ||
299 | /** | |
300 | * clear_inode - clear an inode | |
301 | * @inode: inode to clear | |
302 | * | |
303 | * This is called by the filesystem to tell us | |
304 | * that the inode is no longer useful. We just | |
305 | * terminate it with extreme prejudice. | |
306 | */ | |
307 | void clear_inode(struct inode *inode) | |
308 | { | |
309 | might_sleep(); | |
310 | invalidate_inode_buffers(inode); | |
6b3304b5 | 311 | |
b7542f8c ES |
312 | BUG_ON(inode->i_data.nrpages); |
313 | BUG_ON(!(inode->i_state & I_FREEING)); | |
314 | BUG_ON(inode->i_state & I_CLEAR); | |
1c0eeaf5 | 315 | inode_sync_wait(inode); |
9e3509e2 | 316 | vfs_dq_drop(inode); |
acb0c854 | 317 | if (inode->i_sb->s_op->clear_inode) |
1da177e4 | 318 | inode->i_sb->s_op->clear_inode(inode); |
eaf796e7 | 319 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
1da177e4 | 320 | bd_forget(inode); |
577c4eb0 | 321 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
1da177e4 LT |
322 | cd_forget(inode); |
323 | inode->i_state = I_CLEAR; | |
324 | } | |
1da177e4 LT |
325 | EXPORT_SYMBOL(clear_inode); |
326 | ||
327 | /* | |
328 | * dispose_list - dispose of the contents of a local list | |
329 | * @head: the head of the list to free | |
330 | * | |
331 | * Dispose-list gets a local list with local inodes in it, so it doesn't | |
332 | * need to worry about list corruption and SMP locks. | |
333 | */ | |
334 | static void dispose_list(struct list_head *head) | |
335 | { | |
336 | int nr_disposed = 0; | |
337 | ||
338 | while (!list_empty(head)) { | |
339 | struct inode *inode; | |
340 | ||
b5e61818 | 341 | inode = list_first_entry(head, struct inode, i_list); |
1da177e4 LT |
342 | list_del(&inode->i_list); |
343 | ||
344 | if (inode->i_data.nrpages) | |
345 | truncate_inode_pages(&inode->i_data, 0); | |
346 | clear_inode(inode); | |
4120db47 AB |
347 | |
348 | spin_lock(&inode_lock); | |
349 | hlist_del_init(&inode->i_hash); | |
350 | list_del_init(&inode->i_sb_list); | |
351 | spin_unlock(&inode_lock); | |
352 | ||
353 | wake_up_inode(inode); | |
1da177e4 LT |
354 | destroy_inode(inode); |
355 | nr_disposed++; | |
356 | } | |
357 | spin_lock(&inode_lock); | |
358 | inodes_stat.nr_inodes -= nr_disposed; | |
359 | spin_unlock(&inode_lock); | |
360 | } | |
361 | ||
362 | /* | |
363 | * Invalidate all inodes for a device. | |
364 | */ | |
365 | static int invalidate_list(struct list_head *head, struct list_head *dispose) | |
366 | { | |
367 | struct list_head *next; | |
368 | int busy = 0, count = 0; | |
369 | ||
370 | next = head->next; | |
371 | for (;;) { | |
6b3304b5 MK |
372 | struct list_head *tmp = next; |
373 | struct inode *inode; | |
1da177e4 LT |
374 | |
375 | /* | |
376 | * We can reschedule here without worrying about the list's | |
377 | * consistency because the per-sb list of inodes must not | |
f24075bd | 378 | * change during umount anymore, and because iprune_mutex keeps |
1da177e4 LT |
379 | * shrink_icache_memory() away. |
380 | */ | |
381 | cond_resched_lock(&inode_lock); | |
382 | ||
383 | next = next->next; | |
384 | if (tmp == head) | |
385 | break; | |
386 | inode = list_entry(tmp, struct inode, i_sb_list); | |
aabb8fdb NP |
387 | if (inode->i_state & I_NEW) |
388 | continue; | |
1da177e4 LT |
389 | invalidate_inode_buffers(inode); |
390 | if (!atomic_read(&inode->i_count)) { | |
1da177e4 | 391 | list_move(&inode->i_list, dispose); |
7ef0d737 | 392 | WARN_ON(inode->i_state & I_NEW); |
1da177e4 LT |
393 | inode->i_state |= I_FREEING; |
394 | count++; | |
395 | continue; | |
396 | } | |
397 | busy = 1; | |
398 | } | |
399 | /* only unused inodes may be cached with i_count zero */ | |
400 | inodes_stat.nr_unused -= count; | |
401 | return busy; | |
402 | } | |
403 | ||
1da177e4 LT |
404 | /** |
405 | * invalidate_inodes - discard the inodes on a device | |
406 | * @sb: superblock | |
407 | * | |
408 | * Discard all of the inodes for a given superblock. If the discard | |
409 | * fails because there are busy inodes then a non zero value is returned. | |
410 | * If the discard is successful all the inodes have been discarded. | |
411 | */ | |
6b3304b5 | 412 | int invalidate_inodes(struct super_block *sb) |
1da177e4 LT |
413 | { |
414 | int busy; | |
415 | LIST_HEAD(throw_away); | |
416 | ||
f24075bd | 417 | mutex_lock(&iprune_mutex); |
1da177e4 | 418 | spin_lock(&inode_lock); |
0eeca283 | 419 | inotify_unmount_inodes(&sb->s_inodes); |
164bc619 | 420 | fsnotify_unmount_inodes(&sb->s_inodes); |
1da177e4 LT |
421 | busy = invalidate_list(&sb->s_inodes, &throw_away); |
422 | spin_unlock(&inode_lock); | |
423 | ||
424 | dispose_list(&throw_away); | |
f24075bd | 425 | mutex_unlock(&iprune_mutex); |
1da177e4 LT |
426 | |
427 | return busy; | |
428 | } | |
1da177e4 | 429 | EXPORT_SYMBOL(invalidate_inodes); |
1da177e4 LT |
430 | |
431 | static int can_unuse(struct inode *inode) | |
432 | { | |
433 | if (inode->i_state) | |
434 | return 0; | |
435 | if (inode_has_buffers(inode)) | |
436 | return 0; | |
437 | if (atomic_read(&inode->i_count)) | |
438 | return 0; | |
439 | if (inode->i_data.nrpages) | |
440 | return 0; | |
441 | return 1; | |
442 | } | |
443 | ||
444 | /* | |
445 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to | |
446 | * a temporary list and then are freed outside inode_lock by dispose_list(). | |
447 | * | |
448 | * Any inodes which are pinned purely because of attached pagecache have their | |
449 | * pagecache removed. We expect the final iput() on that inode to add it to | |
450 | * the front of the inode_unused list. So look for it there and if the | |
451 | * inode is still freeable, proceed. The right inode is found 99.9% of the | |
452 | * time in testing on a 4-way. | |
453 | * | |
454 | * If the inode has metadata buffers attached to mapping->private_list then | |
455 | * try to remove them. | |
456 | */ | |
457 | static void prune_icache(int nr_to_scan) | |
458 | { | |
459 | LIST_HEAD(freeable); | |
460 | int nr_pruned = 0; | |
461 | int nr_scanned; | |
462 | unsigned long reap = 0; | |
463 | ||
f24075bd | 464 | mutex_lock(&iprune_mutex); |
1da177e4 LT |
465 | spin_lock(&inode_lock); |
466 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { | |
467 | struct inode *inode; | |
468 | ||
469 | if (list_empty(&inode_unused)) | |
470 | break; | |
471 | ||
472 | inode = list_entry(inode_unused.prev, struct inode, i_list); | |
473 | ||
474 | if (inode->i_state || atomic_read(&inode->i_count)) { | |
475 | list_move(&inode->i_list, &inode_unused); | |
476 | continue; | |
477 | } | |
478 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { | |
479 | __iget(inode); | |
480 | spin_unlock(&inode_lock); | |
481 | if (remove_inode_buffers(inode)) | |
fc0ecff6 AM |
482 | reap += invalidate_mapping_pages(&inode->i_data, |
483 | 0, -1); | |
1da177e4 LT |
484 | iput(inode); |
485 | spin_lock(&inode_lock); | |
486 | ||
487 | if (inode != list_entry(inode_unused.next, | |
488 | struct inode, i_list)) | |
489 | continue; /* wrong inode or list_empty */ | |
490 | if (!can_unuse(inode)) | |
491 | continue; | |
492 | } | |
1da177e4 | 493 | list_move(&inode->i_list, &freeable); |
7ef0d737 | 494 | WARN_ON(inode->i_state & I_NEW); |
1da177e4 LT |
495 | inode->i_state |= I_FREEING; |
496 | nr_pruned++; | |
497 | } | |
498 | inodes_stat.nr_unused -= nr_pruned; | |
f8891e5e CL |
499 | if (current_is_kswapd()) |
500 | __count_vm_events(KSWAPD_INODESTEAL, reap); | |
501 | else | |
502 | __count_vm_events(PGINODESTEAL, reap); | |
1da177e4 LT |
503 | spin_unlock(&inode_lock); |
504 | ||
505 | dispose_list(&freeable); | |
f24075bd | 506 | mutex_unlock(&iprune_mutex); |
1da177e4 LT |
507 | } |
508 | ||
509 | /* | |
510 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, | |
511 | * "unused" means that no dentries are referring to the inodes: the files are | |
512 | * not open and the dcache references to those inodes have already been | |
513 | * reclaimed. | |
514 | * | |
515 | * This function is passed the number of inodes to scan, and it returns the | |
516 | * total number of remaining possibly-reclaimable inodes. | |
517 | */ | |
27496a8c | 518 | static int shrink_icache_memory(int nr, gfp_t gfp_mask) |
1da177e4 LT |
519 | { |
520 | if (nr) { | |
521 | /* | |
522 | * Nasty deadlock avoidance. We may hold various FS locks, | |
523 | * and we don't want to recurse into the FS that called us | |
524 | * in clear_inode() and friends.. | |
6b3304b5 | 525 | */ |
1da177e4 LT |
526 | if (!(gfp_mask & __GFP_FS)) |
527 | return -1; | |
528 | prune_icache(nr); | |
529 | } | |
530 | return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; | |
531 | } | |
532 | ||
8e1f936b RR |
533 | static struct shrinker icache_shrinker = { |
534 | .shrink = shrink_icache_memory, | |
535 | .seeks = DEFAULT_SEEKS, | |
536 | }; | |
537 | ||
1da177e4 LT |
538 | static void __wait_on_freeing_inode(struct inode *inode); |
539 | /* | |
540 | * Called with the inode lock held. | |
541 | * NOTE: we are not increasing the inode-refcount, you must call __iget() | |
542 | * by hand after calling find_inode now! This simplifies iunique and won't | |
543 | * add any additional branch in the common code. | |
544 | */ | |
6b3304b5 MK |
545 | static struct inode *find_inode(struct super_block *sb, |
546 | struct hlist_head *head, | |
547 | int (*test)(struct inode *, void *), | |
548 | void *data) | |
1da177e4 LT |
549 | { |
550 | struct hlist_node *node; | |
6b3304b5 | 551 | struct inode *inode = NULL; |
1da177e4 LT |
552 | |
553 | repeat: | |
c5c8be3c | 554 | hlist_for_each_entry(inode, node, head, i_hash) { |
1da177e4 LT |
555 | if (inode->i_sb != sb) |
556 | continue; | |
557 | if (!test(inode, data)) | |
558 | continue; | |
991114c6 | 559 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
1da177e4 LT |
560 | __wait_on_freeing_inode(inode); |
561 | goto repeat; | |
562 | } | |
563 | break; | |
564 | } | |
565 | return node ? inode : NULL; | |
566 | } | |
567 | ||
568 | /* | |
569 | * find_inode_fast is the fast path version of find_inode, see the comment at | |
570 | * iget_locked for details. | |
571 | */ | |
6b3304b5 MK |
572 | static struct inode *find_inode_fast(struct super_block *sb, |
573 | struct hlist_head *head, unsigned long ino) | |
1da177e4 LT |
574 | { |
575 | struct hlist_node *node; | |
6b3304b5 | 576 | struct inode *inode = NULL; |
1da177e4 LT |
577 | |
578 | repeat: | |
c5c8be3c | 579 | hlist_for_each_entry(inode, node, head, i_hash) { |
1da177e4 LT |
580 | if (inode->i_ino != ino) |
581 | continue; | |
582 | if (inode->i_sb != sb) | |
583 | continue; | |
991114c6 | 584 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
1da177e4 LT |
585 | __wait_on_freeing_inode(inode); |
586 | goto repeat; | |
587 | } | |
588 | break; | |
589 | } | |
590 | return node ? inode : NULL; | |
591 | } | |
592 | ||
8290c35f DC |
593 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
594 | { | |
595 | unsigned long tmp; | |
596 | ||
597 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / | |
598 | L1_CACHE_BYTES; | |
599 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); | |
600 | return tmp & I_HASHMASK; | |
601 | } | |
602 | ||
603 | static inline void | |
604 | __inode_add_to_lists(struct super_block *sb, struct hlist_head *head, | |
605 | struct inode *inode) | |
606 | { | |
607 | inodes_stat.nr_inodes++; | |
608 | list_add(&inode->i_list, &inode_in_use); | |
609 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
610 | if (head) | |
611 | hlist_add_head(&inode->i_hash, head); | |
612 | } | |
613 | ||
614 | /** | |
615 | * inode_add_to_lists - add a new inode to relevant lists | |
0bc02f3f RD |
616 | * @sb: superblock inode belongs to |
617 | * @inode: inode to mark in use | |
8290c35f DC |
618 | * |
619 | * When an inode is allocated it needs to be accounted for, added to the in use | |
620 | * list, the owning superblock and the inode hash. This needs to be done under | |
621 | * the inode_lock, so export a function to do this rather than the inode lock | |
622 | * itself. We calculate the hash list to add to here so it is all internal | |
623 | * which requires the caller to have already set up the inode number in the | |
624 | * inode to add. | |
625 | */ | |
626 | void inode_add_to_lists(struct super_block *sb, struct inode *inode) | |
627 | { | |
628 | struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino); | |
629 | ||
630 | spin_lock(&inode_lock); | |
631 | __inode_add_to_lists(sb, head, inode); | |
632 | spin_unlock(&inode_lock); | |
633 | } | |
634 | EXPORT_SYMBOL_GPL(inode_add_to_lists); | |
635 | ||
1da177e4 LT |
636 | /** |
637 | * new_inode - obtain an inode | |
638 | * @sb: superblock | |
639 | * | |
769848c0 | 640 | * Allocates a new inode for given superblock. The default gfp_mask |
3c1d4378 | 641 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
769848c0 MG |
642 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
643 | * for the page cache are not reclaimable or migratable, | |
644 | * mapping_set_gfp_mask() must be called with suitable flags on the | |
645 | * newly created inode's mapping | |
646 | * | |
1da177e4 LT |
647 | */ |
648 | struct inode *new_inode(struct super_block *sb) | |
649 | { | |
866b04fc JL |
650 | /* |
651 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW | |
652 | * error if st_ino won't fit in target struct field. Use 32bit counter | |
653 | * here to attempt to avoid that. | |
654 | */ | |
655 | static unsigned int last_ino; | |
6b3304b5 | 656 | struct inode *inode; |
1da177e4 LT |
657 | |
658 | spin_lock_prefetch(&inode_lock); | |
6b3304b5 | 659 | |
1da177e4 LT |
660 | inode = alloc_inode(sb); |
661 | if (inode) { | |
662 | spin_lock(&inode_lock); | |
8290c35f | 663 | __inode_add_to_lists(sb, NULL, inode); |
1da177e4 LT |
664 | inode->i_ino = ++last_ino; |
665 | inode->i_state = 0; | |
666 | spin_unlock(&inode_lock); | |
667 | } | |
668 | return inode; | |
669 | } | |
1da177e4 LT |
670 | EXPORT_SYMBOL(new_inode); |
671 | ||
672 | void unlock_new_inode(struct inode *inode) | |
673 | { | |
14358e6d | 674 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
1e89a5e1 PZ |
675 | if (inode->i_mode & S_IFDIR) { |
676 | struct file_system_type *type = inode->i_sb->s_type; | |
677 | ||
9a7aa12f JK |
678 | /* Set new key only if filesystem hasn't already changed it */ |
679 | if (!lockdep_match_class(&inode->i_mutex, | |
680 | &type->i_mutex_key)) { | |
681 | /* | |
682 | * ensure nobody is actually holding i_mutex | |
683 | */ | |
684 | mutex_destroy(&inode->i_mutex); | |
685 | mutex_init(&inode->i_mutex); | |
686 | lockdep_set_class(&inode->i_mutex, | |
687 | &type->i_mutex_dir_key); | |
688 | } | |
1e89a5e1 | 689 | } |
14358e6d | 690 | #endif |
1da177e4 LT |
691 | /* |
692 | * This is special! We do not need the spinlock | |
693 | * when clearing I_LOCK, because we're guaranteed | |
694 | * that nobody else tries to do anything about the | |
695 | * state of the inode when it is locked, as we | |
696 | * just created it (so there can be no old holders | |
697 | * that haven't tested I_LOCK). | |
698 | */ | |
7ef0d737 | 699 | WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW)); |
1da177e4 LT |
700 | inode->i_state &= ~(I_LOCK|I_NEW); |
701 | wake_up_inode(inode); | |
702 | } | |
1da177e4 LT |
703 | EXPORT_SYMBOL(unlock_new_inode); |
704 | ||
705 | /* | |
706 | * This is called without the inode lock held.. Be careful. | |
707 | * | |
708 | * We no longer cache the sb_flags in i_flags - see fs.h | |
709 | * -- rmk@arm.uk.linux.org | |
710 | */ | |
6b3304b5 MK |
711 | static struct inode *get_new_inode(struct super_block *sb, |
712 | struct hlist_head *head, | |
713 | int (*test)(struct inode *, void *), | |
714 | int (*set)(struct inode *, void *), | |
715 | void *data) | |
1da177e4 | 716 | { |
6b3304b5 | 717 | struct inode *inode; |
1da177e4 LT |
718 | |
719 | inode = alloc_inode(sb); | |
720 | if (inode) { | |
6b3304b5 | 721 | struct inode *old; |
1da177e4 LT |
722 | |
723 | spin_lock(&inode_lock); | |
724 | /* We released the lock, so.. */ | |
725 | old = find_inode(sb, head, test, data); | |
726 | if (!old) { | |
727 | if (set(inode, data)) | |
728 | goto set_failed; | |
729 | ||
8290c35f | 730 | __inode_add_to_lists(sb, head, inode); |
1da177e4 LT |
731 | inode->i_state = I_LOCK|I_NEW; |
732 | spin_unlock(&inode_lock); | |
733 | ||
734 | /* Return the locked inode with I_NEW set, the | |
735 | * caller is responsible for filling in the contents | |
736 | */ | |
737 | return inode; | |
738 | } | |
739 | ||
740 | /* | |
741 | * Uhhuh, somebody else created the same inode under | |
742 | * us. Use the old inode instead of the one we just | |
743 | * allocated. | |
744 | */ | |
745 | __iget(old); | |
746 | spin_unlock(&inode_lock); | |
747 | destroy_inode(inode); | |
748 | inode = old; | |
749 | wait_on_inode(inode); | |
750 | } | |
751 | return inode; | |
752 | ||
753 | set_failed: | |
754 | spin_unlock(&inode_lock); | |
755 | destroy_inode(inode); | |
756 | return NULL; | |
757 | } | |
758 | ||
759 | /* | |
760 | * get_new_inode_fast is the fast path version of get_new_inode, see the | |
761 | * comment at iget_locked for details. | |
762 | */ | |
6b3304b5 MK |
763 | static struct inode *get_new_inode_fast(struct super_block *sb, |
764 | struct hlist_head *head, unsigned long ino) | |
1da177e4 | 765 | { |
6b3304b5 | 766 | struct inode *inode; |
1da177e4 LT |
767 | |
768 | inode = alloc_inode(sb); | |
769 | if (inode) { | |
6b3304b5 | 770 | struct inode *old; |
1da177e4 LT |
771 | |
772 | spin_lock(&inode_lock); | |
773 | /* We released the lock, so.. */ | |
774 | old = find_inode_fast(sb, head, ino); | |
775 | if (!old) { | |
776 | inode->i_ino = ino; | |
8290c35f | 777 | __inode_add_to_lists(sb, head, inode); |
1da177e4 LT |
778 | inode->i_state = I_LOCK|I_NEW; |
779 | spin_unlock(&inode_lock); | |
780 | ||
781 | /* Return the locked inode with I_NEW set, the | |
782 | * caller is responsible for filling in the contents | |
783 | */ | |
784 | return inode; | |
785 | } | |
786 | ||
787 | /* | |
788 | * Uhhuh, somebody else created the same inode under | |
789 | * us. Use the old inode instead of the one we just | |
790 | * allocated. | |
791 | */ | |
792 | __iget(old); | |
793 | spin_unlock(&inode_lock); | |
794 | destroy_inode(inode); | |
795 | inode = old; | |
796 | wait_on_inode(inode); | |
797 | } | |
798 | return inode; | |
799 | } | |
800 | ||
1da177e4 LT |
801 | /** |
802 | * iunique - get a unique inode number | |
803 | * @sb: superblock | |
804 | * @max_reserved: highest reserved inode number | |
805 | * | |
806 | * Obtain an inode number that is unique on the system for a given | |
807 | * superblock. This is used by file systems that have no natural | |
808 | * permanent inode numbering system. An inode number is returned that | |
809 | * is higher than the reserved limit but unique. | |
810 | * | |
811 | * BUGS: | |
812 | * With a large number of inodes live on the file system this function | |
813 | * currently becomes quite slow. | |
814 | */ | |
815 | ino_t iunique(struct super_block *sb, ino_t max_reserved) | |
816 | { | |
866b04fc JL |
817 | /* |
818 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW | |
819 | * error if st_ino won't fit in target struct field. Use 32bit counter | |
820 | * here to attempt to avoid that. | |
821 | */ | |
822 | static unsigned int counter; | |
1da177e4 | 823 | struct inode *inode; |
3361c7be | 824 | struct hlist_head *head; |
1da177e4 | 825 | ino_t res; |
3361c7be | 826 | |
1da177e4 | 827 | spin_lock(&inode_lock); |
3361c7be JL |
828 | do { |
829 | if (counter <= max_reserved) | |
830 | counter = max_reserved + 1; | |
1da177e4 | 831 | res = counter++; |
3361c7be | 832 | head = inode_hashtable + hash(sb, res); |
1da177e4 | 833 | inode = find_inode_fast(sb, head, res); |
3361c7be JL |
834 | } while (inode != NULL); |
835 | spin_unlock(&inode_lock); | |
1da177e4 | 836 | |
3361c7be JL |
837 | return res; |
838 | } | |
1da177e4 LT |
839 | EXPORT_SYMBOL(iunique); |
840 | ||
841 | struct inode *igrab(struct inode *inode) | |
842 | { | |
843 | spin_lock(&inode_lock); | |
4a3b0a49 | 844 | if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))) |
1da177e4 LT |
845 | __iget(inode); |
846 | else | |
847 | /* | |
848 | * Handle the case where s_op->clear_inode is not been | |
849 | * called yet, and somebody is calling igrab | |
850 | * while the inode is getting freed. | |
851 | */ | |
852 | inode = NULL; | |
853 | spin_unlock(&inode_lock); | |
854 | return inode; | |
855 | } | |
1da177e4 LT |
856 | EXPORT_SYMBOL(igrab); |
857 | ||
858 | /** | |
859 | * ifind - internal function, you want ilookup5() or iget5(). | |
860 | * @sb: super block of file system to search | |
861 | * @head: the head of the list to search | |
862 | * @test: callback used for comparisons between inodes | |
863 | * @data: opaque data pointer to pass to @test | |
88bd5121 | 864 | * @wait: if true wait for the inode to be unlocked, if false do not |
1da177e4 LT |
865 | * |
866 | * ifind() searches for the inode specified by @data in the inode | |
867 | * cache. This is a generalized version of ifind_fast() for file systems where | |
868 | * the inode number is not sufficient for unique identification of an inode. | |
869 | * | |
870 | * If the inode is in the cache, the inode is returned with an incremented | |
871 | * reference count. | |
872 | * | |
873 | * Otherwise NULL is returned. | |
874 | * | |
875 | * Note, @test is called with the inode_lock held, so can't sleep. | |
876 | */ | |
5d2bea45 | 877 | static struct inode *ifind(struct super_block *sb, |
1da177e4 | 878 | struct hlist_head *head, int (*test)(struct inode *, void *), |
88bd5121 | 879 | void *data, const int wait) |
1da177e4 LT |
880 | { |
881 | struct inode *inode; | |
882 | ||
883 | spin_lock(&inode_lock); | |
884 | inode = find_inode(sb, head, test, data); | |
885 | if (inode) { | |
886 | __iget(inode); | |
887 | spin_unlock(&inode_lock); | |
88bd5121 AA |
888 | if (likely(wait)) |
889 | wait_on_inode(inode); | |
1da177e4 LT |
890 | return inode; |
891 | } | |
892 | spin_unlock(&inode_lock); | |
893 | return NULL; | |
894 | } | |
895 | ||
896 | /** | |
897 | * ifind_fast - internal function, you want ilookup() or iget(). | |
898 | * @sb: super block of file system to search | |
899 | * @head: head of the list to search | |
900 | * @ino: inode number to search for | |
901 | * | |
902 | * ifind_fast() searches for the inode @ino in the inode cache. This is for | |
903 | * file systems where the inode number is sufficient for unique identification | |
904 | * of an inode. | |
905 | * | |
906 | * If the inode is in the cache, the inode is returned with an incremented | |
907 | * reference count. | |
908 | * | |
909 | * Otherwise NULL is returned. | |
910 | */ | |
5d2bea45 | 911 | static struct inode *ifind_fast(struct super_block *sb, |
1da177e4 LT |
912 | struct hlist_head *head, unsigned long ino) |
913 | { | |
914 | struct inode *inode; | |
915 | ||
916 | spin_lock(&inode_lock); | |
917 | inode = find_inode_fast(sb, head, ino); | |
918 | if (inode) { | |
919 | __iget(inode); | |
920 | spin_unlock(&inode_lock); | |
921 | wait_on_inode(inode); | |
922 | return inode; | |
923 | } | |
924 | spin_unlock(&inode_lock); | |
925 | return NULL; | |
926 | } | |
927 | ||
928 | /** | |
88bd5121 | 929 | * ilookup5_nowait - search for an inode in the inode cache |
1da177e4 LT |
930 | * @sb: super block of file system to search |
931 | * @hashval: hash value (usually inode number) to search for | |
932 | * @test: callback used for comparisons between inodes | |
933 | * @data: opaque data pointer to pass to @test | |
934 | * | |
935 | * ilookup5() uses ifind() to search for the inode specified by @hashval and | |
936 | * @data in the inode cache. This is a generalized version of ilookup() for | |
937 | * file systems where the inode number is not sufficient for unique | |
938 | * identification of an inode. | |
939 | * | |
940 | * If the inode is in the cache, the inode is returned with an incremented | |
88bd5121 AA |
941 | * reference count. Note, the inode lock is not waited upon so you have to be |
942 | * very careful what you do with the returned inode. You probably should be | |
943 | * using ilookup5() instead. | |
944 | * | |
945 | * Otherwise NULL is returned. | |
946 | * | |
947 | * Note, @test is called with the inode_lock held, so can't sleep. | |
948 | */ | |
949 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, | |
950 | int (*test)(struct inode *, void *), void *data) | |
951 | { | |
952 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
953 | ||
954 | return ifind(sb, head, test, data, 0); | |
955 | } | |
88bd5121 AA |
956 | EXPORT_SYMBOL(ilookup5_nowait); |
957 | ||
958 | /** | |
959 | * ilookup5 - search for an inode in the inode cache | |
960 | * @sb: super block of file system to search | |
961 | * @hashval: hash value (usually inode number) to search for | |
962 | * @test: callback used for comparisons between inodes | |
963 | * @data: opaque data pointer to pass to @test | |
964 | * | |
965 | * ilookup5() uses ifind() to search for the inode specified by @hashval and | |
966 | * @data in the inode cache. This is a generalized version of ilookup() for | |
967 | * file systems where the inode number is not sufficient for unique | |
968 | * identification of an inode. | |
969 | * | |
970 | * If the inode is in the cache, the inode lock is waited upon and the inode is | |
971 | * returned with an incremented reference count. | |
1da177e4 LT |
972 | * |
973 | * Otherwise NULL is returned. | |
974 | * | |
975 | * Note, @test is called with the inode_lock held, so can't sleep. | |
976 | */ | |
977 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, | |
978 | int (*test)(struct inode *, void *), void *data) | |
979 | { | |
980 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
981 | ||
88bd5121 | 982 | return ifind(sb, head, test, data, 1); |
1da177e4 | 983 | } |
1da177e4 LT |
984 | EXPORT_SYMBOL(ilookup5); |
985 | ||
986 | /** | |
987 | * ilookup - search for an inode in the inode cache | |
988 | * @sb: super block of file system to search | |
989 | * @ino: inode number to search for | |
990 | * | |
991 | * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. | |
992 | * This is for file systems where the inode number is sufficient for unique | |
993 | * identification of an inode. | |
994 | * | |
995 | * If the inode is in the cache, the inode is returned with an incremented | |
996 | * reference count. | |
997 | * | |
998 | * Otherwise NULL is returned. | |
999 | */ | |
1000 | struct inode *ilookup(struct super_block *sb, unsigned long ino) | |
1001 | { | |
1002 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
1003 | ||
1004 | return ifind_fast(sb, head, ino); | |
1005 | } | |
1da177e4 LT |
1006 | EXPORT_SYMBOL(ilookup); |
1007 | ||
1008 | /** | |
1009 | * iget5_locked - obtain an inode from a mounted file system | |
1010 | * @sb: super block of file system | |
1011 | * @hashval: hash value (usually inode number) to get | |
1012 | * @test: callback used for comparisons between inodes | |
1013 | * @set: callback used to initialize a new struct inode | |
1014 | * @data: opaque data pointer to pass to @test and @set | |
1015 | * | |
1da177e4 LT |
1016 | * iget5_locked() uses ifind() to search for the inode specified by @hashval |
1017 | * and @data in the inode cache and if present it is returned with an increased | |
1018 | * reference count. This is a generalized version of iget_locked() for file | |
1019 | * systems where the inode number is not sufficient for unique identification | |
1020 | * of an inode. | |
1021 | * | |
1022 | * If the inode is not in cache, get_new_inode() is called to allocate a new | |
1023 | * inode and this is returned locked, hashed, and with the I_NEW flag set. The | |
1024 | * file system gets to fill it in before unlocking it via unlock_new_inode(). | |
1025 | * | |
1026 | * Note both @test and @set are called with the inode_lock held, so can't sleep. | |
1027 | */ | |
1028 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, | |
1029 | int (*test)(struct inode *, void *), | |
1030 | int (*set)(struct inode *, void *), void *data) | |
1031 | { | |
1032 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
1033 | struct inode *inode; | |
1034 | ||
88bd5121 | 1035 | inode = ifind(sb, head, test, data, 1); |
1da177e4 LT |
1036 | if (inode) |
1037 | return inode; | |
1038 | /* | |
1039 | * get_new_inode() will do the right thing, re-trying the search | |
1040 | * in case it had to block at any point. | |
1041 | */ | |
1042 | return get_new_inode(sb, head, test, set, data); | |
1043 | } | |
1da177e4 LT |
1044 | EXPORT_SYMBOL(iget5_locked); |
1045 | ||
1046 | /** | |
1047 | * iget_locked - obtain an inode from a mounted file system | |
1048 | * @sb: super block of file system | |
1049 | * @ino: inode number to get | |
1050 | * | |
1da177e4 LT |
1051 | * iget_locked() uses ifind_fast() to search for the inode specified by @ino in |
1052 | * the inode cache and if present it is returned with an increased reference | |
1053 | * count. This is for file systems where the inode number is sufficient for | |
1054 | * unique identification of an inode. | |
1055 | * | |
1056 | * If the inode is not in cache, get_new_inode_fast() is called to allocate a | |
1057 | * new inode and this is returned locked, hashed, and with the I_NEW flag set. | |
1058 | * The file system gets to fill it in before unlocking it via | |
1059 | * unlock_new_inode(). | |
1060 | */ | |
1061 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) | |
1062 | { | |
1063 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
1064 | struct inode *inode; | |
1065 | ||
1066 | inode = ifind_fast(sb, head, ino); | |
1067 | if (inode) | |
1068 | return inode; | |
1069 | /* | |
1070 | * get_new_inode_fast() will do the right thing, re-trying the search | |
1071 | * in case it had to block at any point. | |
1072 | */ | |
1073 | return get_new_inode_fast(sb, head, ino); | |
1074 | } | |
1da177e4 LT |
1075 | EXPORT_SYMBOL(iget_locked); |
1076 | ||
261bca86 AV |
1077 | int insert_inode_locked(struct inode *inode) |
1078 | { | |
1079 | struct super_block *sb = inode->i_sb; | |
1080 | ino_t ino = inode->i_ino; | |
1081 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
261bca86 AV |
1082 | |
1083 | inode->i_state |= I_LOCK|I_NEW; | |
1084 | while (1) { | |
72a43d63 AV |
1085 | struct hlist_node *node; |
1086 | struct inode *old = NULL; | |
261bca86 | 1087 | spin_lock(&inode_lock); |
72a43d63 AV |
1088 | hlist_for_each_entry(old, node, head, i_hash) { |
1089 | if (old->i_ino != ino) | |
1090 | continue; | |
1091 | if (old->i_sb != sb) | |
1092 | continue; | |
1093 | if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) | |
1094 | continue; | |
1095 | break; | |
1096 | } | |
1097 | if (likely(!node)) { | |
261bca86 AV |
1098 | hlist_add_head(&inode->i_hash, head); |
1099 | spin_unlock(&inode_lock); | |
1100 | return 0; | |
1101 | } | |
1102 | __iget(old); | |
1103 | spin_unlock(&inode_lock); | |
1104 | wait_on_inode(old); | |
1105 | if (unlikely(!hlist_unhashed(&old->i_hash))) { | |
1106 | iput(old); | |
1107 | return -EBUSY; | |
1108 | } | |
1109 | iput(old); | |
1110 | } | |
1111 | } | |
261bca86 AV |
1112 | EXPORT_SYMBOL(insert_inode_locked); |
1113 | ||
1114 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, | |
1115 | int (*test)(struct inode *, void *), void *data) | |
1116 | { | |
1117 | struct super_block *sb = inode->i_sb; | |
1118 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
261bca86 AV |
1119 | |
1120 | inode->i_state |= I_LOCK|I_NEW; | |
1121 | ||
1122 | while (1) { | |
72a43d63 AV |
1123 | struct hlist_node *node; |
1124 | struct inode *old = NULL; | |
1125 | ||
261bca86 | 1126 | spin_lock(&inode_lock); |
72a43d63 AV |
1127 | hlist_for_each_entry(old, node, head, i_hash) { |
1128 | if (old->i_sb != sb) | |
1129 | continue; | |
1130 | if (!test(old, data)) | |
1131 | continue; | |
1132 | if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) | |
1133 | continue; | |
1134 | break; | |
1135 | } | |
1136 | if (likely(!node)) { | |
261bca86 AV |
1137 | hlist_add_head(&inode->i_hash, head); |
1138 | spin_unlock(&inode_lock); | |
1139 | return 0; | |
1140 | } | |
1141 | __iget(old); | |
1142 | spin_unlock(&inode_lock); | |
1143 | wait_on_inode(old); | |
1144 | if (unlikely(!hlist_unhashed(&old->i_hash))) { | |
1145 | iput(old); | |
1146 | return -EBUSY; | |
1147 | } | |
1148 | iput(old); | |
1149 | } | |
1150 | } | |
261bca86 AV |
1151 | EXPORT_SYMBOL(insert_inode_locked4); |
1152 | ||
1da177e4 LT |
1153 | /** |
1154 | * __insert_inode_hash - hash an inode | |
1155 | * @inode: unhashed inode | |
1156 | * @hashval: unsigned long value used to locate this object in the | |
1157 | * inode_hashtable. | |
1158 | * | |
1159 | * Add an inode to the inode hash for this superblock. | |
1160 | */ | |
1161 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) | |
1162 | { | |
1163 | struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); | |
1164 | spin_lock(&inode_lock); | |
1165 | hlist_add_head(&inode->i_hash, head); | |
1166 | spin_unlock(&inode_lock); | |
1167 | } | |
1da177e4 LT |
1168 | EXPORT_SYMBOL(__insert_inode_hash); |
1169 | ||
1170 | /** | |
1171 | * remove_inode_hash - remove an inode from the hash | |
1172 | * @inode: inode to unhash | |
1173 | * | |
1174 | * Remove an inode from the superblock. | |
1175 | */ | |
1176 | void remove_inode_hash(struct inode *inode) | |
1177 | { | |
1178 | spin_lock(&inode_lock); | |
1179 | hlist_del_init(&inode->i_hash); | |
1180 | spin_unlock(&inode_lock); | |
1181 | } | |
1da177e4 LT |
1182 | EXPORT_SYMBOL(remove_inode_hash); |
1183 | ||
1184 | /* | |
1185 | * Tell the filesystem that this inode is no longer of any interest and should | |
1186 | * be completely destroyed. | |
1187 | * | |
1188 | * We leave the inode in the inode hash table until *after* the filesystem's | |
1189 | * ->delete_inode completes. This ensures that an iget (such as nfsd might | |
1190 | * instigate) will always find up-to-date information either in the hash or on | |
1191 | * disk. | |
1192 | * | |
1193 | * I_FREEING is set so that no-one will take a new reference to the inode while | |
1194 | * it is being deleted. | |
1195 | */ | |
b32714ba | 1196 | void generic_delete_inode(struct inode *inode) |
1da177e4 | 1197 | { |
ee9b6d61 | 1198 | const struct super_operations *op = inode->i_sb->s_op; |
1da177e4 | 1199 | |
b32714ba AV |
1200 | list_del_init(&inode->i_list); |
1201 | list_del_init(&inode->i_sb_list); | |
7ef0d737 | 1202 | WARN_ON(inode->i_state & I_NEW); |
b32714ba AV |
1203 | inode->i_state |= I_FREEING; |
1204 | inodes_stat.nr_inodes--; | |
1205 | spin_unlock(&inode_lock); | |
1206 | ||
1da177e4 LT |
1207 | security_inode_delete(inode); |
1208 | ||
1209 | if (op->delete_inode) { | |
1210 | void (*delete)(struct inode *) = op->delete_inode; | |
1211 | if (!is_bad_inode(inode)) | |
9e3509e2 | 1212 | vfs_dq_init(inode); |
e85b5652 MF |
1213 | /* Filesystems implementing their own |
1214 | * s_op->delete_inode are required to call | |
1215 | * truncate_inode_pages and clear_inode() | |
1216 | * internally */ | |
1da177e4 | 1217 | delete(inode); |
e85b5652 MF |
1218 | } else { |
1219 | truncate_inode_pages(&inode->i_data, 0); | |
1da177e4 | 1220 | clear_inode(inode); |
e85b5652 | 1221 | } |
1da177e4 LT |
1222 | spin_lock(&inode_lock); |
1223 | hlist_del_init(&inode->i_hash); | |
1224 | spin_unlock(&inode_lock); | |
1225 | wake_up_inode(inode); | |
b7542f8c | 1226 | BUG_ON(inode->i_state != I_CLEAR); |
1da177e4 LT |
1227 | destroy_inode(inode); |
1228 | } | |
1da177e4 LT |
1229 | EXPORT_SYMBOL(generic_delete_inode); |
1230 | ||
1231 | static void generic_forget_inode(struct inode *inode) | |
1232 | { | |
1233 | struct super_block *sb = inode->i_sb; | |
1234 | ||
1235 | if (!hlist_unhashed(&inode->i_hash)) { | |
1c0eeaf5 | 1236 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1da177e4 LT |
1237 | list_move(&inode->i_list, &inode_unused); |
1238 | inodes_stat.nr_unused++; | |
acb0c854 | 1239 | if (sb->s_flags & MS_ACTIVE) { |
991114c6 | 1240 | spin_unlock(&inode_lock); |
1da177e4 | 1241 | return; |
991114c6 | 1242 | } |
7ef0d737 | 1243 | WARN_ON(inode->i_state & I_NEW); |
991114c6 AV |
1244 | inode->i_state |= I_WILL_FREE; |
1245 | spin_unlock(&inode_lock); | |
1da177e4 LT |
1246 | write_inode_now(inode, 1); |
1247 | spin_lock(&inode_lock); | |
7ef0d737 | 1248 | WARN_ON(inode->i_state & I_NEW); |
991114c6 | 1249 | inode->i_state &= ~I_WILL_FREE; |
1da177e4 LT |
1250 | inodes_stat.nr_unused--; |
1251 | hlist_del_init(&inode->i_hash); | |
1252 | } | |
1253 | list_del_init(&inode->i_list); | |
1254 | list_del_init(&inode->i_sb_list); | |
7ef0d737 | 1255 | WARN_ON(inode->i_state & I_NEW); |
991114c6 | 1256 | inode->i_state |= I_FREEING; |
1da177e4 LT |
1257 | inodes_stat.nr_inodes--; |
1258 | spin_unlock(&inode_lock); | |
1259 | if (inode->i_data.nrpages) | |
1260 | truncate_inode_pages(&inode->i_data, 0); | |
1261 | clear_inode(inode); | |
7f04c26d | 1262 | wake_up_inode(inode); |
1da177e4 LT |
1263 | destroy_inode(inode); |
1264 | } | |
1265 | ||
1266 | /* | |
1267 | * Normal UNIX filesystem behaviour: delete the | |
1268 | * inode when the usage count drops to zero, and | |
1269 | * i_nlink is zero. | |
1270 | */ | |
cb2c0233 | 1271 | void generic_drop_inode(struct inode *inode) |
1da177e4 LT |
1272 | { |
1273 | if (!inode->i_nlink) | |
1274 | generic_delete_inode(inode); | |
1275 | else | |
1276 | generic_forget_inode(inode); | |
1277 | } | |
cb2c0233 MF |
1278 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1279 | ||
1da177e4 LT |
1280 | /* |
1281 | * Called when we're dropping the last reference | |
6b3304b5 | 1282 | * to an inode. |
1da177e4 LT |
1283 | * |
1284 | * Call the FS "drop()" function, defaulting to | |
1285 | * the legacy UNIX filesystem behaviour.. | |
1286 | * | |
1287 | * NOTE! NOTE! NOTE! We're called with the inode lock | |
1288 | * held, and the drop function is supposed to release | |
1289 | * the lock! | |
1290 | */ | |
1291 | static inline void iput_final(struct inode *inode) | |
1292 | { | |
ee9b6d61 | 1293 | const struct super_operations *op = inode->i_sb->s_op; |
1da177e4 LT |
1294 | void (*drop)(struct inode *) = generic_drop_inode; |
1295 | ||
1296 | if (op && op->drop_inode) | |
1297 | drop = op->drop_inode; | |
1298 | drop(inode); | |
1299 | } | |
1300 | ||
1301 | /** | |
6b3304b5 | 1302 | * iput - put an inode |
1da177e4 LT |
1303 | * @inode: inode to put |
1304 | * | |
1305 | * Puts an inode, dropping its usage count. If the inode use count hits | |
1306 | * zero, the inode is then freed and may also be destroyed. | |
1307 | * | |
1308 | * Consequently, iput() can sleep. | |
1309 | */ | |
1310 | void iput(struct inode *inode) | |
1311 | { | |
1312 | if (inode) { | |
1da177e4 LT |
1313 | BUG_ON(inode->i_state == I_CLEAR); |
1314 | ||
1da177e4 LT |
1315 | if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) |
1316 | iput_final(inode); | |
1317 | } | |
1318 | } | |
1da177e4 LT |
1319 | EXPORT_SYMBOL(iput); |
1320 | ||
1321 | /** | |
1322 | * bmap - find a block number in a file | |
1323 | * @inode: inode of file | |
1324 | * @block: block to find | |
1325 | * | |
1326 | * Returns the block number on the device holding the inode that | |
1327 | * is the disk block number for the block of the file requested. | |
1328 | * That is, asked for block 4 of inode 1 the function will return the | |
6b3304b5 | 1329 | * disk block relative to the disk start that holds that block of the |
1da177e4 LT |
1330 | * file. |
1331 | */ | |
6b3304b5 | 1332 | sector_t bmap(struct inode *inode, sector_t block) |
1da177e4 LT |
1333 | { |
1334 | sector_t res = 0; | |
1335 | if (inode->i_mapping->a_ops->bmap) | |
1336 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); | |
1337 | return res; | |
1338 | } | |
1da177e4 LT |
1339 | EXPORT_SYMBOL(bmap); |
1340 | ||
11ff6f05 MG |
1341 | /* |
1342 | * With relative atime, only update atime if the previous atime is | |
1343 | * earlier than either the ctime or mtime or if at least a day has | |
1344 | * passed since the last atime update. | |
1345 | */ | |
1346 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, | |
1347 | struct timespec now) | |
1348 | { | |
1349 | ||
1350 | if (!(mnt->mnt_flags & MNT_RELATIME)) | |
1351 | return 1; | |
1352 | /* | |
1353 | * Is mtime younger than atime? If yes, update atime: | |
1354 | */ | |
1355 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) | |
1356 | return 1; | |
1357 | /* | |
1358 | * Is ctime younger than atime? If yes, update atime: | |
1359 | */ | |
1360 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) | |
1361 | return 1; | |
1362 | ||
1363 | /* | |
1364 | * Is the previous atime value older than a day? If yes, | |
1365 | * update atime: | |
1366 | */ | |
1367 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) | |
1368 | return 1; | |
1369 | /* | |
1370 | * Good, we can skip the atime update: | |
1371 | */ | |
1372 | return 0; | |
1373 | } | |
1374 | ||
1da177e4 | 1375 | /** |
869243a0 CH |
1376 | * touch_atime - update the access time |
1377 | * @mnt: mount the inode is accessed on | |
7045f37b | 1378 | * @dentry: dentry accessed |
1da177e4 LT |
1379 | * |
1380 | * Update the accessed time on an inode and mark it for writeback. | |
1381 | * This function automatically handles read only file systems and media, | |
1382 | * as well as the "noatime" flag and inode specific "noatime" markers. | |
1383 | */ | |
869243a0 | 1384 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1da177e4 | 1385 | { |
869243a0 | 1386 | struct inode *inode = dentry->d_inode; |
1da177e4 LT |
1387 | struct timespec now; |
1388 | ||
cdb70f3f | 1389 | if (mnt_want_write(mnt)) |
b2276138 | 1390 | return; |
cdb70f3f DH |
1391 | if (inode->i_flags & S_NOATIME) |
1392 | goto out; | |
37756ced | 1393 | if (IS_NOATIME(inode)) |
cdb70f3f | 1394 | goto out; |
b2276138 | 1395 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
cdb70f3f | 1396 | goto out; |
47ae32d6 | 1397 | |
cdb70f3f DH |
1398 | if (mnt->mnt_flags & MNT_NOATIME) |
1399 | goto out; | |
1400 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) | |
1401 | goto out; | |
1da177e4 LT |
1402 | |
1403 | now = current_fs_time(inode->i_sb); | |
11ff6f05 MG |
1404 | |
1405 | if (!relatime_need_update(mnt, inode, now)) | |
1406 | goto out; | |
1407 | ||
47ae32d6 | 1408 | if (timespec_equal(&inode->i_atime, &now)) |
cdb70f3f | 1409 | goto out; |
47ae32d6 VH |
1410 | |
1411 | inode->i_atime = now; | |
1412 | mark_inode_dirty_sync(inode); | |
cdb70f3f DH |
1413 | out: |
1414 | mnt_drop_write(mnt); | |
1da177e4 | 1415 | } |
869243a0 | 1416 | EXPORT_SYMBOL(touch_atime); |
1da177e4 LT |
1417 | |
1418 | /** | |
870f4817 CH |
1419 | * file_update_time - update mtime and ctime time |
1420 | * @file: file accessed | |
1da177e4 | 1421 | * |
870f4817 CH |
1422 | * Update the mtime and ctime members of an inode and mark the inode |
1423 | * for writeback. Note that this function is meant exclusively for | |
1424 | * usage in the file write path of filesystems, and filesystems may | |
1425 | * choose to explicitly ignore update via this function with the | |
2eadfc0e | 1426 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
870f4817 | 1427 | * timestamps are handled by the server. |
1da177e4 LT |
1428 | */ |
1429 | ||
870f4817 | 1430 | void file_update_time(struct file *file) |
1da177e4 | 1431 | { |
0f7fc9e4 | 1432 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1433 | struct timespec now; |
1434 | int sync_it = 0; | |
20ddee2c | 1435 | int err; |
1da177e4 LT |
1436 | |
1437 | if (IS_NOCMTIME(inode)) | |
1438 | return; | |
20ddee2c | 1439 | |
96029c4e | 1440 | err = mnt_want_write_file(file); |
20ddee2c | 1441 | if (err) |
1da177e4 LT |
1442 | return; |
1443 | ||
1444 | now = current_fs_time(inode->i_sb); | |
ed97bd37 AM |
1445 | if (!timespec_equal(&inode->i_mtime, &now)) { |
1446 | inode->i_mtime = now; | |
1da177e4 | 1447 | sync_it = 1; |
ed97bd37 | 1448 | } |
1da177e4 | 1449 | |
ed97bd37 AM |
1450 | if (!timespec_equal(&inode->i_ctime, &now)) { |
1451 | inode->i_ctime = now; | |
870f4817 | 1452 | sync_it = 1; |
ed97bd37 | 1453 | } |
870f4817 | 1454 | |
7a224228 JNC |
1455 | if (IS_I_VERSION(inode)) { |
1456 | inode_inc_iversion(inode); | |
1457 | sync_it = 1; | |
1458 | } | |
1459 | ||
1da177e4 LT |
1460 | if (sync_it) |
1461 | mark_inode_dirty_sync(inode); | |
20ddee2c | 1462 | mnt_drop_write(file->f_path.mnt); |
1da177e4 | 1463 | } |
870f4817 | 1464 | EXPORT_SYMBOL(file_update_time); |
1da177e4 LT |
1465 | |
1466 | int inode_needs_sync(struct inode *inode) | |
1467 | { | |
1468 | if (IS_SYNC(inode)) | |
1469 | return 1; | |
1470 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) | |
1471 | return 1; | |
1472 | return 0; | |
1473 | } | |
1da177e4 LT |
1474 | EXPORT_SYMBOL(inode_needs_sync); |
1475 | ||
1da177e4 LT |
1476 | int inode_wait(void *word) |
1477 | { | |
1478 | schedule(); | |
1479 | return 0; | |
1480 | } | |
d44dab8d | 1481 | EXPORT_SYMBOL(inode_wait); |
1da177e4 LT |
1482 | |
1483 | /* | |
168a9fd6 MS |
1484 | * If we try to find an inode in the inode hash while it is being |
1485 | * deleted, we have to wait until the filesystem completes its | |
1486 | * deletion before reporting that it isn't found. This function waits | |
1487 | * until the deletion _might_ have completed. Callers are responsible | |
1488 | * to recheck inode state. | |
1489 | * | |
1490 | * It doesn't matter if I_LOCK is not set initially, a call to | |
1491 | * wake_up_inode() after removing from the hash list will DTRT. | |
1492 | * | |
1da177e4 LT |
1493 | * This is called with inode_lock held. |
1494 | */ | |
1495 | static void __wait_on_freeing_inode(struct inode *inode) | |
1496 | { | |
1497 | wait_queue_head_t *wq; | |
1498 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK); | |
1da177e4 LT |
1499 | wq = bit_waitqueue(&inode->i_state, __I_LOCK); |
1500 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); | |
1501 | spin_unlock(&inode_lock); | |
1502 | schedule(); | |
1503 | finish_wait(wq, &wait.wait); | |
1504 | spin_lock(&inode_lock); | |
1505 | } | |
1506 | ||
1da177e4 LT |
1507 | static __initdata unsigned long ihash_entries; |
1508 | static int __init set_ihash_entries(char *str) | |
1509 | { | |
1510 | if (!str) | |
1511 | return 0; | |
1512 | ihash_entries = simple_strtoul(str, &str, 0); | |
1513 | return 1; | |
1514 | } | |
1515 | __setup("ihash_entries=", set_ihash_entries); | |
1516 | ||
1517 | /* | |
1518 | * Initialize the waitqueues and inode hash table. | |
1519 | */ | |
1520 | void __init inode_init_early(void) | |
1521 | { | |
1522 | int loop; | |
1523 | ||
1524 | /* If hashes are distributed across NUMA nodes, defer | |
1525 | * hash allocation until vmalloc space is available. | |
1526 | */ | |
1527 | if (hashdist) | |
1528 | return; | |
1529 | ||
1530 | inode_hashtable = | |
1531 | alloc_large_system_hash("Inode-cache", | |
1532 | sizeof(struct hlist_head), | |
1533 | ihash_entries, | |
1534 | 14, | |
1535 | HASH_EARLY, | |
1536 | &i_hash_shift, | |
1537 | &i_hash_mask, | |
1538 | 0); | |
1539 | ||
1540 | for (loop = 0; loop < (1 << i_hash_shift); loop++) | |
1541 | INIT_HLIST_HEAD(&inode_hashtable[loop]); | |
1542 | } | |
1543 | ||
74bf17cf | 1544 | void __init inode_init(void) |
1da177e4 LT |
1545 | { |
1546 | int loop; | |
1547 | ||
1548 | /* inode slab cache */ | |
b0196009 PJ |
1549 | inode_cachep = kmem_cache_create("inode_cache", |
1550 | sizeof(struct inode), | |
1551 | 0, | |
1552 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| | |
1553 | SLAB_MEM_SPREAD), | |
20c2df83 | 1554 | init_once); |
8e1f936b | 1555 | register_shrinker(&icache_shrinker); |
1da177e4 LT |
1556 | |
1557 | /* Hash may have been set up in inode_init_early */ | |
1558 | if (!hashdist) | |
1559 | return; | |
1560 | ||
1561 | inode_hashtable = | |
1562 | alloc_large_system_hash("Inode-cache", | |
1563 | sizeof(struct hlist_head), | |
1564 | ihash_entries, | |
1565 | 14, | |
1566 | 0, | |
1567 | &i_hash_shift, | |
1568 | &i_hash_mask, | |
1569 | 0); | |
1570 | ||
1571 | for (loop = 0; loop < (1 << i_hash_shift); loop++) | |
1572 | INIT_HLIST_HEAD(&inode_hashtable[loop]); | |
1573 | } | |
1574 | ||
1575 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) | |
1576 | { | |
1577 | inode->i_mode = mode; | |
1578 | if (S_ISCHR(mode)) { | |
1579 | inode->i_fop = &def_chr_fops; | |
1580 | inode->i_rdev = rdev; | |
1581 | } else if (S_ISBLK(mode)) { | |
1582 | inode->i_fop = &def_blk_fops; | |
1583 | inode->i_rdev = rdev; | |
1584 | } else if (S_ISFIFO(mode)) | |
1585 | inode->i_fop = &def_fifo_fops; | |
1586 | else if (S_ISSOCK(mode)) | |
1587 | inode->i_fop = &bad_sock_fops; | |
1588 | else | |
1589 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n", | |
1590 | mode); | |
1591 | } | |
1592 | EXPORT_SYMBOL(init_special_inode); |