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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 | ||
7 | #include <linux/config.h> | |
8 | #include <linux/fs.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/dcache.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/quotaops.h> | |
13 | #include <linux/slab.h> | |
14 | #include <linux/writeback.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/backing-dev.h> | |
17 | #include <linux/wait.h> | |
18 | #include <linux/hash.h> | |
19 | #include <linux/swap.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/pagemap.h> | |
22 | #include <linux/cdev.h> | |
23 | #include <linux/bootmem.h> | |
0eeca283 | 24 | #include <linux/inotify.h> |
fc33a7bb | 25 | #include <linux/mount.h> |
1da177e4 LT |
26 | |
27 | /* | |
28 | * This is needed for the following functions: | |
29 | * - inode_has_buffers | |
30 | * - invalidate_inode_buffers | |
1da177e4 LT |
31 | * - invalidate_bdev |
32 | * | |
33 | * FIXME: remove all knowledge of the buffer layer from this file | |
34 | */ | |
35 | #include <linux/buffer_head.h> | |
36 | ||
37 | /* | |
38 | * New inode.c implementation. | |
39 | * | |
40 | * This implementation has the basic premise of trying | |
41 | * to be extremely low-overhead and SMP-safe, yet be | |
42 | * simple enough to be "obviously correct". | |
43 | * | |
44 | * Famous last words. | |
45 | */ | |
46 | ||
47 | /* inode dynamic allocation 1999, Andrea Arcangeli <[email protected]> */ | |
48 | ||
49 | /* #define INODE_PARANOIA 1 */ | |
50 | /* #define INODE_DEBUG 1 */ | |
51 | ||
52 | /* | |
53 | * Inode lookup is no longer as critical as it used to be: | |
54 | * most of the lookups are going to be through the dcache. | |
55 | */ | |
56 | #define I_HASHBITS i_hash_shift | |
57 | #define I_HASHMASK i_hash_mask | |
58 | ||
59 | static unsigned int i_hash_mask; | |
60 | static unsigned int i_hash_shift; | |
61 | ||
62 | /* | |
63 | * Each inode can be on two separate lists. One is | |
64 | * the hash list of the inode, used for lookups. The | |
65 | * other linked list is the "type" list: | |
66 | * "in_use" - valid inode, i_count > 0, i_nlink > 0 | |
67 | * "dirty" - as "in_use" but also dirty | |
68 | * "unused" - valid inode, i_count = 0 | |
69 | * | |
70 | * A "dirty" list is maintained for each super block, | |
71 | * allowing for low-overhead inode sync() operations. | |
72 | */ | |
73 | ||
74 | LIST_HEAD(inode_in_use); | |
75 | LIST_HEAD(inode_unused); | |
76 | static struct hlist_head *inode_hashtable; | |
77 | ||
78 | /* | |
79 | * A simple spinlock to protect the list manipulations. | |
80 | * | |
81 | * NOTE! You also have to own the lock if you change | |
82 | * the i_state of an inode while it is in use.. | |
83 | */ | |
84 | DEFINE_SPINLOCK(inode_lock); | |
85 | ||
86 | /* | |
87 | * iprune_sem provides exclusion between the kswapd or try_to_free_pages | |
88 | * icache shrinking path, and the umount path. Without this exclusion, | |
89 | * by the time prune_icache calls iput for the inode whose pages it has | |
90 | * been invalidating, or by the time it calls clear_inode & destroy_inode | |
91 | * from its final dispose_list, the struct super_block they refer to | |
92 | * (for inode->i_sb->s_op) may already have been freed and reused. | |
93 | */ | |
94 | DECLARE_MUTEX(iprune_sem); | |
95 | ||
96 | /* | |
97 | * Statistics gathering.. | |
98 | */ | |
99 | struct inodes_stat_t inodes_stat; | |
100 | ||
101 | static kmem_cache_t * inode_cachep; | |
102 | ||
103 | static struct inode *alloc_inode(struct super_block *sb) | |
104 | { | |
105 | static struct address_space_operations empty_aops; | |
106 | static struct inode_operations empty_iops; | |
107 | static struct file_operations empty_fops; | |
108 | struct inode *inode; | |
109 | ||
110 | if (sb->s_op->alloc_inode) | |
111 | inode = sb->s_op->alloc_inode(sb); | |
112 | else | |
113 | inode = (struct inode *) kmem_cache_alloc(inode_cachep, SLAB_KERNEL); | |
114 | ||
115 | if (inode) { | |
116 | struct address_space * const mapping = &inode->i_data; | |
117 | ||
118 | inode->i_sb = sb; | |
119 | inode->i_blkbits = sb->s_blocksize_bits; | |
120 | inode->i_flags = 0; | |
121 | atomic_set(&inode->i_count, 1); | |
122 | inode->i_op = &empty_iops; | |
123 | inode->i_fop = &empty_fops; | |
124 | inode->i_nlink = 1; | |
125 | atomic_set(&inode->i_writecount, 0); | |
126 | inode->i_size = 0; | |
127 | inode->i_blocks = 0; | |
128 | inode->i_bytes = 0; | |
129 | inode->i_generation = 0; | |
130 | #ifdef CONFIG_QUOTA | |
131 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); | |
132 | #endif | |
133 | inode->i_pipe = NULL; | |
134 | inode->i_bdev = NULL; | |
135 | inode->i_cdev = NULL; | |
136 | inode->i_rdev = 0; | |
137 | inode->i_security = NULL; | |
138 | inode->dirtied_when = 0; | |
139 | if (security_inode_alloc(inode)) { | |
140 | if (inode->i_sb->s_op->destroy_inode) | |
141 | inode->i_sb->s_op->destroy_inode(inode); | |
142 | else | |
143 | kmem_cache_free(inode_cachep, (inode)); | |
144 | return NULL; | |
145 | } | |
146 | ||
147 | mapping->a_ops = &empty_aops; | |
148 | mapping->host = inode; | |
149 | mapping->flags = 0; | |
150 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER); | |
151 | mapping->assoc_mapping = NULL; | |
152 | mapping->backing_dev_info = &default_backing_dev_info; | |
153 | ||
154 | /* | |
155 | * If the block_device provides a backing_dev_info for client | |
156 | * inodes then use that. Otherwise the inode share the bdev's | |
157 | * backing_dev_info. | |
158 | */ | |
159 | if (sb->s_bdev) { | |
160 | struct backing_dev_info *bdi; | |
161 | ||
162 | bdi = sb->s_bdev->bd_inode_backing_dev_info; | |
163 | if (!bdi) | |
164 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; | |
165 | mapping->backing_dev_info = bdi; | |
166 | } | |
167 | memset(&inode->u, 0, sizeof(inode->u)); | |
168 | inode->i_mapping = mapping; | |
169 | } | |
170 | return inode; | |
171 | } | |
172 | ||
173 | void destroy_inode(struct inode *inode) | |
174 | { | |
175 | if (inode_has_buffers(inode)) | |
176 | BUG(); | |
177 | security_inode_free(inode); | |
178 | if (inode->i_sb->s_op->destroy_inode) | |
179 | inode->i_sb->s_op->destroy_inode(inode); | |
180 | else | |
181 | kmem_cache_free(inode_cachep, (inode)); | |
182 | } | |
183 | ||
184 | ||
185 | /* | |
186 | * These are initializations that only need to be done | |
187 | * once, because the fields are idempotent across use | |
188 | * of the inode, so let the slab aware of that. | |
189 | */ | |
190 | void inode_init_once(struct inode *inode) | |
191 | { | |
192 | memset(inode, 0, sizeof(*inode)); | |
193 | INIT_HLIST_NODE(&inode->i_hash); | |
194 | INIT_LIST_HEAD(&inode->i_dentry); | |
195 | INIT_LIST_HEAD(&inode->i_devices); | |
1b1dcc1b | 196 | mutex_init(&inode->i_mutex); |
1da177e4 LT |
197 | init_rwsem(&inode->i_alloc_sem); |
198 | INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); | |
199 | rwlock_init(&inode->i_data.tree_lock); | |
200 | spin_lock_init(&inode->i_data.i_mmap_lock); | |
201 | INIT_LIST_HEAD(&inode->i_data.private_list); | |
202 | spin_lock_init(&inode->i_data.private_lock); | |
203 | INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap); | |
204 | INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear); | |
205 | spin_lock_init(&inode->i_lock); | |
206 | i_size_ordered_init(inode); | |
0eeca283 RL |
207 | #ifdef CONFIG_INOTIFY |
208 | INIT_LIST_HEAD(&inode->inotify_watches); | |
209 | sema_init(&inode->inotify_sem, 1); | |
210 | #endif | |
1da177e4 LT |
211 | } |
212 | ||
213 | EXPORT_SYMBOL(inode_init_once); | |
214 | ||
215 | static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags) | |
216 | { | |
217 | struct inode * inode = (struct inode *) foo; | |
218 | ||
219 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | |
220 | SLAB_CTOR_CONSTRUCTOR) | |
221 | inode_init_once(inode); | |
222 | } | |
223 | ||
224 | /* | |
225 | * inode_lock must be held | |
226 | */ | |
227 | void __iget(struct inode * inode) | |
228 | { | |
229 | if (atomic_read(&inode->i_count)) { | |
230 | atomic_inc(&inode->i_count); | |
231 | return; | |
232 | } | |
233 | atomic_inc(&inode->i_count); | |
234 | if (!(inode->i_state & (I_DIRTY|I_LOCK))) | |
235 | list_move(&inode->i_list, &inode_in_use); | |
236 | inodes_stat.nr_unused--; | |
237 | } | |
238 | ||
239 | /** | |
240 | * clear_inode - clear an inode | |
241 | * @inode: inode to clear | |
242 | * | |
243 | * This is called by the filesystem to tell us | |
244 | * that the inode is no longer useful. We just | |
245 | * terminate it with extreme prejudice. | |
246 | */ | |
247 | void clear_inode(struct inode *inode) | |
248 | { | |
249 | might_sleep(); | |
250 | invalidate_inode_buffers(inode); | |
251 | ||
252 | if (inode->i_data.nrpages) | |
253 | BUG(); | |
254 | if (!(inode->i_state & I_FREEING)) | |
255 | BUG(); | |
256 | if (inode->i_state & I_CLEAR) | |
257 | BUG(); | |
258 | wait_on_inode(inode); | |
259 | DQUOT_DROP(inode); | |
260 | if (inode->i_sb && inode->i_sb->s_op->clear_inode) | |
261 | inode->i_sb->s_op->clear_inode(inode); | |
262 | if (inode->i_bdev) | |
263 | bd_forget(inode); | |
264 | if (inode->i_cdev) | |
265 | cd_forget(inode); | |
266 | inode->i_state = I_CLEAR; | |
267 | } | |
268 | ||
269 | EXPORT_SYMBOL(clear_inode); | |
270 | ||
271 | /* | |
272 | * dispose_list - dispose of the contents of a local list | |
273 | * @head: the head of the list to free | |
274 | * | |
275 | * Dispose-list gets a local list with local inodes in it, so it doesn't | |
276 | * need to worry about list corruption and SMP locks. | |
277 | */ | |
278 | static void dispose_list(struct list_head *head) | |
279 | { | |
280 | int nr_disposed = 0; | |
281 | ||
282 | while (!list_empty(head)) { | |
283 | struct inode *inode; | |
284 | ||
285 | inode = list_entry(head->next, struct inode, i_list); | |
286 | list_del(&inode->i_list); | |
287 | ||
288 | if (inode->i_data.nrpages) | |
289 | truncate_inode_pages(&inode->i_data, 0); | |
290 | clear_inode(inode); | |
4120db47 AB |
291 | |
292 | spin_lock(&inode_lock); | |
293 | hlist_del_init(&inode->i_hash); | |
294 | list_del_init(&inode->i_sb_list); | |
295 | spin_unlock(&inode_lock); | |
296 | ||
297 | wake_up_inode(inode); | |
1da177e4 LT |
298 | destroy_inode(inode); |
299 | nr_disposed++; | |
300 | } | |
301 | spin_lock(&inode_lock); | |
302 | inodes_stat.nr_inodes -= nr_disposed; | |
303 | spin_unlock(&inode_lock); | |
304 | } | |
305 | ||
306 | /* | |
307 | * Invalidate all inodes for a device. | |
308 | */ | |
309 | static int invalidate_list(struct list_head *head, struct list_head *dispose) | |
310 | { | |
311 | struct list_head *next; | |
312 | int busy = 0, count = 0; | |
313 | ||
314 | next = head->next; | |
315 | for (;;) { | |
316 | struct list_head * tmp = next; | |
317 | struct inode * inode; | |
318 | ||
319 | /* | |
320 | * We can reschedule here without worrying about the list's | |
321 | * consistency because the per-sb list of inodes must not | |
322 | * change during umount anymore, and because iprune_sem keeps | |
323 | * shrink_icache_memory() away. | |
324 | */ | |
325 | cond_resched_lock(&inode_lock); | |
326 | ||
327 | next = next->next; | |
328 | if (tmp == head) | |
329 | break; | |
330 | inode = list_entry(tmp, struct inode, i_sb_list); | |
331 | invalidate_inode_buffers(inode); | |
332 | if (!atomic_read(&inode->i_count)) { | |
1da177e4 LT |
333 | list_move(&inode->i_list, dispose); |
334 | inode->i_state |= I_FREEING; | |
335 | count++; | |
336 | continue; | |
337 | } | |
338 | busy = 1; | |
339 | } | |
340 | /* only unused inodes may be cached with i_count zero */ | |
341 | inodes_stat.nr_unused -= count; | |
342 | return busy; | |
343 | } | |
344 | ||
1da177e4 LT |
345 | /** |
346 | * invalidate_inodes - discard the inodes on a device | |
347 | * @sb: superblock | |
348 | * | |
349 | * Discard all of the inodes for a given superblock. If the discard | |
350 | * fails because there are busy inodes then a non zero value is returned. | |
351 | * If the discard is successful all the inodes have been discarded. | |
352 | */ | |
353 | int invalidate_inodes(struct super_block * sb) | |
354 | { | |
355 | int busy; | |
356 | LIST_HEAD(throw_away); | |
357 | ||
358 | down(&iprune_sem); | |
359 | spin_lock(&inode_lock); | |
0eeca283 | 360 | inotify_unmount_inodes(&sb->s_inodes); |
1da177e4 LT |
361 | busy = invalidate_list(&sb->s_inodes, &throw_away); |
362 | spin_unlock(&inode_lock); | |
363 | ||
364 | dispose_list(&throw_away); | |
365 | up(&iprune_sem); | |
366 | ||
367 | return busy; | |
368 | } | |
369 | ||
370 | EXPORT_SYMBOL(invalidate_inodes); | |
371 | ||
2ef41634 | 372 | int __invalidate_device(struct block_device *bdev) |
1da177e4 | 373 | { |
2ef41634 CH |
374 | struct super_block *sb = get_super(bdev); |
375 | int res = 0; | |
1da177e4 | 376 | |
1da177e4 LT |
377 | if (sb) { |
378 | /* | |
379 | * no need to lock the super, get_super holds the | |
380 | * read semaphore so the filesystem cannot go away | |
381 | * under us (->put_super runs with the write lock | |
382 | * hold). | |
383 | */ | |
384 | shrink_dcache_sb(sb); | |
385 | res = invalidate_inodes(sb); | |
386 | drop_super(sb); | |
387 | } | |
388 | invalidate_bdev(bdev, 0); | |
389 | return res; | |
390 | } | |
1da177e4 LT |
391 | EXPORT_SYMBOL(__invalidate_device); |
392 | ||
393 | static int can_unuse(struct inode *inode) | |
394 | { | |
395 | if (inode->i_state) | |
396 | return 0; | |
397 | if (inode_has_buffers(inode)) | |
398 | return 0; | |
399 | if (atomic_read(&inode->i_count)) | |
400 | return 0; | |
401 | if (inode->i_data.nrpages) | |
402 | return 0; | |
403 | return 1; | |
404 | } | |
405 | ||
406 | /* | |
407 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to | |
408 | * a temporary list and then are freed outside inode_lock by dispose_list(). | |
409 | * | |
410 | * Any inodes which are pinned purely because of attached pagecache have their | |
411 | * pagecache removed. We expect the final iput() on that inode to add it to | |
412 | * the front of the inode_unused list. So look for it there and if the | |
413 | * inode is still freeable, proceed. The right inode is found 99.9% of the | |
414 | * time in testing on a 4-way. | |
415 | * | |
416 | * If the inode has metadata buffers attached to mapping->private_list then | |
417 | * try to remove them. | |
418 | */ | |
419 | static void prune_icache(int nr_to_scan) | |
420 | { | |
421 | LIST_HEAD(freeable); | |
422 | int nr_pruned = 0; | |
423 | int nr_scanned; | |
424 | unsigned long reap = 0; | |
425 | ||
426 | down(&iprune_sem); | |
427 | spin_lock(&inode_lock); | |
428 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { | |
429 | struct inode *inode; | |
430 | ||
431 | if (list_empty(&inode_unused)) | |
432 | break; | |
433 | ||
434 | inode = list_entry(inode_unused.prev, struct inode, i_list); | |
435 | ||
436 | if (inode->i_state || atomic_read(&inode->i_count)) { | |
437 | list_move(&inode->i_list, &inode_unused); | |
438 | continue; | |
439 | } | |
440 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { | |
441 | __iget(inode); | |
442 | spin_unlock(&inode_lock); | |
443 | if (remove_inode_buffers(inode)) | |
444 | reap += invalidate_inode_pages(&inode->i_data); | |
445 | iput(inode); | |
446 | spin_lock(&inode_lock); | |
447 | ||
448 | if (inode != list_entry(inode_unused.next, | |
449 | struct inode, i_list)) | |
450 | continue; /* wrong inode or list_empty */ | |
451 | if (!can_unuse(inode)) | |
452 | continue; | |
453 | } | |
1da177e4 LT |
454 | list_move(&inode->i_list, &freeable); |
455 | inode->i_state |= I_FREEING; | |
456 | nr_pruned++; | |
457 | } | |
458 | inodes_stat.nr_unused -= nr_pruned; | |
459 | spin_unlock(&inode_lock); | |
460 | ||
461 | dispose_list(&freeable); | |
462 | up(&iprune_sem); | |
463 | ||
464 | if (current_is_kswapd()) | |
465 | mod_page_state(kswapd_inodesteal, reap); | |
466 | else | |
467 | mod_page_state(pginodesteal, reap); | |
468 | } | |
469 | ||
470 | /* | |
471 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, | |
472 | * "unused" means that no dentries are referring to the inodes: the files are | |
473 | * not open and the dcache references to those inodes have already been | |
474 | * reclaimed. | |
475 | * | |
476 | * This function is passed the number of inodes to scan, and it returns the | |
477 | * total number of remaining possibly-reclaimable inodes. | |
478 | */ | |
27496a8c | 479 | static int shrink_icache_memory(int nr, gfp_t gfp_mask) |
1da177e4 LT |
480 | { |
481 | if (nr) { | |
482 | /* | |
483 | * Nasty deadlock avoidance. We may hold various FS locks, | |
484 | * and we don't want to recurse into the FS that called us | |
485 | * in clear_inode() and friends.. | |
486 | */ | |
487 | if (!(gfp_mask & __GFP_FS)) | |
488 | return -1; | |
489 | prune_icache(nr); | |
490 | } | |
491 | return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; | |
492 | } | |
493 | ||
494 | static void __wait_on_freeing_inode(struct inode *inode); | |
495 | /* | |
496 | * Called with the inode lock held. | |
497 | * NOTE: we are not increasing the inode-refcount, you must call __iget() | |
498 | * by hand after calling find_inode now! This simplifies iunique and won't | |
499 | * add any additional branch in the common code. | |
500 | */ | |
501 | static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data) | |
502 | { | |
503 | struct hlist_node *node; | |
504 | struct inode * inode = NULL; | |
505 | ||
506 | repeat: | |
507 | hlist_for_each (node, head) { | |
508 | inode = hlist_entry(node, struct inode, i_hash); | |
509 | if (inode->i_sb != sb) | |
510 | continue; | |
511 | if (!test(inode, data)) | |
512 | continue; | |
991114c6 | 513 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
1da177e4 LT |
514 | __wait_on_freeing_inode(inode); |
515 | goto repeat; | |
516 | } | |
517 | break; | |
518 | } | |
519 | return node ? inode : NULL; | |
520 | } | |
521 | ||
522 | /* | |
523 | * find_inode_fast is the fast path version of find_inode, see the comment at | |
524 | * iget_locked for details. | |
525 | */ | |
526 | static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino) | |
527 | { | |
528 | struct hlist_node *node; | |
529 | struct inode * inode = NULL; | |
530 | ||
531 | repeat: | |
532 | hlist_for_each (node, head) { | |
533 | inode = hlist_entry(node, struct inode, i_hash); | |
534 | if (inode->i_ino != ino) | |
535 | continue; | |
536 | if (inode->i_sb != sb) | |
537 | continue; | |
991114c6 | 538 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
1da177e4 LT |
539 | __wait_on_freeing_inode(inode); |
540 | goto repeat; | |
541 | } | |
542 | break; | |
543 | } | |
544 | return node ? inode : NULL; | |
545 | } | |
546 | ||
547 | /** | |
548 | * new_inode - obtain an inode | |
549 | * @sb: superblock | |
550 | * | |
551 | * Allocates a new inode for given superblock. | |
552 | */ | |
553 | struct inode *new_inode(struct super_block *sb) | |
554 | { | |
555 | static unsigned long last_ino; | |
556 | struct inode * inode; | |
557 | ||
558 | spin_lock_prefetch(&inode_lock); | |
559 | ||
560 | inode = alloc_inode(sb); | |
561 | if (inode) { | |
562 | spin_lock(&inode_lock); | |
563 | inodes_stat.nr_inodes++; | |
564 | list_add(&inode->i_list, &inode_in_use); | |
565 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
566 | inode->i_ino = ++last_ino; | |
567 | inode->i_state = 0; | |
568 | spin_unlock(&inode_lock); | |
569 | } | |
570 | return inode; | |
571 | } | |
572 | ||
573 | EXPORT_SYMBOL(new_inode); | |
574 | ||
575 | void unlock_new_inode(struct inode *inode) | |
576 | { | |
577 | /* | |
578 | * This is special! We do not need the spinlock | |
579 | * when clearing I_LOCK, because we're guaranteed | |
580 | * that nobody else tries to do anything about the | |
581 | * state of the inode when it is locked, as we | |
582 | * just created it (so there can be no old holders | |
583 | * that haven't tested I_LOCK). | |
584 | */ | |
585 | inode->i_state &= ~(I_LOCK|I_NEW); | |
586 | wake_up_inode(inode); | |
587 | } | |
588 | ||
589 | EXPORT_SYMBOL(unlock_new_inode); | |
590 | ||
591 | /* | |
592 | * This is called without the inode lock held.. Be careful. | |
593 | * | |
594 | * We no longer cache the sb_flags in i_flags - see fs.h | |
595 | * -- [email protected] | |
596 | */ | |
597 | static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data) | |
598 | { | |
599 | struct inode * inode; | |
600 | ||
601 | inode = alloc_inode(sb); | |
602 | if (inode) { | |
603 | struct inode * old; | |
604 | ||
605 | spin_lock(&inode_lock); | |
606 | /* We released the lock, so.. */ | |
607 | old = find_inode(sb, head, test, data); | |
608 | if (!old) { | |
609 | if (set(inode, data)) | |
610 | goto set_failed; | |
611 | ||
612 | inodes_stat.nr_inodes++; | |
613 | list_add(&inode->i_list, &inode_in_use); | |
614 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
615 | hlist_add_head(&inode->i_hash, head); | |
616 | inode->i_state = I_LOCK|I_NEW; | |
617 | spin_unlock(&inode_lock); | |
618 | ||
619 | /* Return the locked inode with I_NEW set, the | |
620 | * caller is responsible for filling in the contents | |
621 | */ | |
622 | return inode; | |
623 | } | |
624 | ||
625 | /* | |
626 | * Uhhuh, somebody else created the same inode under | |
627 | * us. Use the old inode instead of the one we just | |
628 | * allocated. | |
629 | */ | |
630 | __iget(old); | |
631 | spin_unlock(&inode_lock); | |
632 | destroy_inode(inode); | |
633 | inode = old; | |
634 | wait_on_inode(inode); | |
635 | } | |
636 | return inode; | |
637 | ||
638 | set_failed: | |
639 | spin_unlock(&inode_lock); | |
640 | destroy_inode(inode); | |
641 | return NULL; | |
642 | } | |
643 | ||
644 | /* | |
645 | * get_new_inode_fast is the fast path version of get_new_inode, see the | |
646 | * comment at iget_locked for details. | |
647 | */ | |
648 | static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino) | |
649 | { | |
650 | struct inode * inode; | |
651 | ||
652 | inode = alloc_inode(sb); | |
653 | if (inode) { | |
654 | struct inode * old; | |
655 | ||
656 | spin_lock(&inode_lock); | |
657 | /* We released the lock, so.. */ | |
658 | old = find_inode_fast(sb, head, ino); | |
659 | if (!old) { | |
660 | inode->i_ino = ino; | |
661 | inodes_stat.nr_inodes++; | |
662 | list_add(&inode->i_list, &inode_in_use); | |
663 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
664 | hlist_add_head(&inode->i_hash, head); | |
665 | inode->i_state = I_LOCK|I_NEW; | |
666 | spin_unlock(&inode_lock); | |
667 | ||
668 | /* Return the locked inode with I_NEW set, the | |
669 | * caller is responsible for filling in the contents | |
670 | */ | |
671 | return inode; | |
672 | } | |
673 | ||
674 | /* | |
675 | * Uhhuh, somebody else created the same inode under | |
676 | * us. Use the old inode instead of the one we just | |
677 | * allocated. | |
678 | */ | |
679 | __iget(old); | |
680 | spin_unlock(&inode_lock); | |
681 | destroy_inode(inode); | |
682 | inode = old; | |
683 | wait_on_inode(inode); | |
684 | } | |
685 | return inode; | |
686 | } | |
687 | ||
688 | static inline unsigned long hash(struct super_block *sb, unsigned long hashval) | |
689 | { | |
690 | unsigned long tmp; | |
691 | ||
692 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / | |
693 | L1_CACHE_BYTES; | |
694 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); | |
695 | return tmp & I_HASHMASK; | |
696 | } | |
697 | ||
698 | /** | |
699 | * iunique - get a unique inode number | |
700 | * @sb: superblock | |
701 | * @max_reserved: highest reserved inode number | |
702 | * | |
703 | * Obtain an inode number that is unique on the system for a given | |
704 | * superblock. This is used by file systems that have no natural | |
705 | * permanent inode numbering system. An inode number is returned that | |
706 | * is higher than the reserved limit but unique. | |
707 | * | |
708 | * BUGS: | |
709 | * With a large number of inodes live on the file system this function | |
710 | * currently becomes quite slow. | |
711 | */ | |
712 | ino_t iunique(struct super_block *sb, ino_t max_reserved) | |
713 | { | |
714 | static ino_t counter; | |
715 | struct inode *inode; | |
716 | struct hlist_head * head; | |
717 | ino_t res; | |
718 | spin_lock(&inode_lock); | |
719 | retry: | |
720 | if (counter > max_reserved) { | |
721 | head = inode_hashtable + hash(sb,counter); | |
722 | res = counter++; | |
723 | inode = find_inode_fast(sb, head, res); | |
724 | if (!inode) { | |
725 | spin_unlock(&inode_lock); | |
726 | return res; | |
727 | } | |
728 | } else { | |
729 | counter = max_reserved + 1; | |
730 | } | |
731 | goto retry; | |
732 | ||
733 | } | |
734 | ||
735 | EXPORT_SYMBOL(iunique); | |
736 | ||
737 | struct inode *igrab(struct inode *inode) | |
738 | { | |
739 | spin_lock(&inode_lock); | |
991114c6 | 740 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) |
1da177e4 LT |
741 | __iget(inode); |
742 | else | |
743 | /* | |
744 | * Handle the case where s_op->clear_inode is not been | |
745 | * called yet, and somebody is calling igrab | |
746 | * while the inode is getting freed. | |
747 | */ | |
748 | inode = NULL; | |
749 | spin_unlock(&inode_lock); | |
750 | return inode; | |
751 | } | |
752 | ||
753 | EXPORT_SYMBOL(igrab); | |
754 | ||
755 | /** | |
756 | * ifind - internal function, you want ilookup5() or iget5(). | |
757 | * @sb: super block of file system to search | |
758 | * @head: the head of the list to search | |
759 | * @test: callback used for comparisons between inodes | |
760 | * @data: opaque data pointer to pass to @test | |
88bd5121 | 761 | * @wait: if true wait for the inode to be unlocked, if false do not |
1da177e4 LT |
762 | * |
763 | * ifind() searches for the inode specified by @data in the inode | |
764 | * cache. This is a generalized version of ifind_fast() for file systems where | |
765 | * the inode number is not sufficient for unique identification of an inode. | |
766 | * | |
767 | * If the inode is in the cache, the inode is returned with an incremented | |
768 | * reference count. | |
769 | * | |
770 | * Otherwise NULL is returned. | |
771 | * | |
772 | * Note, @test is called with the inode_lock held, so can't sleep. | |
773 | */ | |
5d2bea45 | 774 | static struct inode *ifind(struct super_block *sb, |
1da177e4 | 775 | struct hlist_head *head, int (*test)(struct inode *, void *), |
88bd5121 | 776 | void *data, const int wait) |
1da177e4 LT |
777 | { |
778 | struct inode *inode; | |
779 | ||
780 | spin_lock(&inode_lock); | |
781 | inode = find_inode(sb, head, test, data); | |
782 | if (inode) { | |
783 | __iget(inode); | |
784 | spin_unlock(&inode_lock); | |
88bd5121 AA |
785 | if (likely(wait)) |
786 | wait_on_inode(inode); | |
1da177e4 LT |
787 | return inode; |
788 | } | |
789 | spin_unlock(&inode_lock); | |
790 | return NULL; | |
791 | } | |
792 | ||
793 | /** | |
794 | * ifind_fast - internal function, you want ilookup() or iget(). | |
795 | * @sb: super block of file system to search | |
796 | * @head: head of the list to search | |
797 | * @ino: inode number to search for | |
798 | * | |
799 | * ifind_fast() searches for the inode @ino in the inode cache. This is for | |
800 | * file systems where the inode number is sufficient for unique identification | |
801 | * of an inode. | |
802 | * | |
803 | * If the inode is in the cache, the inode is returned with an incremented | |
804 | * reference count. | |
805 | * | |
806 | * Otherwise NULL is returned. | |
807 | */ | |
5d2bea45 | 808 | static struct inode *ifind_fast(struct super_block *sb, |
1da177e4 LT |
809 | struct hlist_head *head, unsigned long ino) |
810 | { | |
811 | struct inode *inode; | |
812 | ||
813 | spin_lock(&inode_lock); | |
814 | inode = find_inode_fast(sb, head, ino); | |
815 | if (inode) { | |
816 | __iget(inode); | |
817 | spin_unlock(&inode_lock); | |
818 | wait_on_inode(inode); | |
819 | return inode; | |
820 | } | |
821 | spin_unlock(&inode_lock); | |
822 | return NULL; | |
823 | } | |
824 | ||
825 | /** | |
88bd5121 | 826 | * ilookup5_nowait - search for an inode in the inode cache |
1da177e4 LT |
827 | * @sb: super block of file system to search |
828 | * @hashval: hash value (usually inode number) to search for | |
829 | * @test: callback used for comparisons between inodes | |
830 | * @data: opaque data pointer to pass to @test | |
831 | * | |
832 | * ilookup5() uses ifind() to search for the inode specified by @hashval and | |
833 | * @data in the inode cache. This is a generalized version of ilookup() for | |
834 | * file systems where the inode number is not sufficient for unique | |
835 | * identification of an inode. | |
836 | * | |
837 | * If the inode is in the cache, the inode is returned with an incremented | |
88bd5121 AA |
838 | * reference count. Note, the inode lock is not waited upon so you have to be |
839 | * very careful what you do with the returned inode. You probably should be | |
840 | * using ilookup5() instead. | |
841 | * | |
842 | * Otherwise NULL is returned. | |
843 | * | |
844 | * Note, @test is called with the inode_lock held, so can't sleep. | |
845 | */ | |
846 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, | |
847 | int (*test)(struct inode *, void *), void *data) | |
848 | { | |
849 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
850 | ||
851 | return ifind(sb, head, test, data, 0); | |
852 | } | |
853 | ||
854 | EXPORT_SYMBOL(ilookup5_nowait); | |
855 | ||
856 | /** | |
857 | * ilookup5 - search for an inode in the inode cache | |
858 | * @sb: super block of file system to search | |
859 | * @hashval: hash value (usually inode number) to search for | |
860 | * @test: callback used for comparisons between inodes | |
861 | * @data: opaque data pointer to pass to @test | |
862 | * | |
863 | * ilookup5() uses ifind() to search for the inode specified by @hashval and | |
864 | * @data in the inode cache. This is a generalized version of ilookup() for | |
865 | * file systems where the inode number is not sufficient for unique | |
866 | * identification of an inode. | |
867 | * | |
868 | * If the inode is in the cache, the inode lock is waited upon and the inode is | |
869 | * returned with an incremented reference count. | |
1da177e4 LT |
870 | * |
871 | * Otherwise NULL is returned. | |
872 | * | |
873 | * Note, @test is called with the inode_lock held, so can't sleep. | |
874 | */ | |
875 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, | |
876 | int (*test)(struct inode *, void *), void *data) | |
877 | { | |
878 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
879 | ||
88bd5121 | 880 | return ifind(sb, head, test, data, 1); |
1da177e4 LT |
881 | } |
882 | ||
883 | EXPORT_SYMBOL(ilookup5); | |
884 | ||
885 | /** | |
886 | * ilookup - search for an inode in the inode cache | |
887 | * @sb: super block of file system to search | |
888 | * @ino: inode number to search for | |
889 | * | |
890 | * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. | |
891 | * This is for file systems where the inode number is sufficient for unique | |
892 | * identification of an inode. | |
893 | * | |
894 | * If the inode is in the cache, the inode is returned with an incremented | |
895 | * reference count. | |
896 | * | |
897 | * Otherwise NULL is returned. | |
898 | */ | |
899 | struct inode *ilookup(struct super_block *sb, unsigned long ino) | |
900 | { | |
901 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
902 | ||
903 | return ifind_fast(sb, head, ino); | |
904 | } | |
905 | ||
906 | EXPORT_SYMBOL(ilookup); | |
907 | ||
908 | /** | |
909 | * iget5_locked - obtain an inode from a mounted file system | |
910 | * @sb: super block of file system | |
911 | * @hashval: hash value (usually inode number) to get | |
912 | * @test: callback used for comparisons between inodes | |
913 | * @set: callback used to initialize a new struct inode | |
914 | * @data: opaque data pointer to pass to @test and @set | |
915 | * | |
916 | * This is iget() without the read_inode() portion of get_new_inode(). | |
917 | * | |
918 | * iget5_locked() uses ifind() to search for the inode specified by @hashval | |
919 | * and @data in the inode cache and if present it is returned with an increased | |
920 | * reference count. This is a generalized version of iget_locked() for file | |
921 | * systems where the inode number is not sufficient for unique identification | |
922 | * of an inode. | |
923 | * | |
924 | * If the inode is not in cache, get_new_inode() is called to allocate a new | |
925 | * inode and this is returned locked, hashed, and with the I_NEW flag set. The | |
926 | * file system gets to fill it in before unlocking it via unlock_new_inode(). | |
927 | * | |
928 | * Note both @test and @set are called with the inode_lock held, so can't sleep. | |
929 | */ | |
930 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, | |
931 | int (*test)(struct inode *, void *), | |
932 | int (*set)(struct inode *, void *), void *data) | |
933 | { | |
934 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
935 | struct inode *inode; | |
936 | ||
88bd5121 | 937 | inode = ifind(sb, head, test, data, 1); |
1da177e4 LT |
938 | if (inode) |
939 | return inode; | |
940 | /* | |
941 | * get_new_inode() will do the right thing, re-trying the search | |
942 | * in case it had to block at any point. | |
943 | */ | |
944 | return get_new_inode(sb, head, test, set, data); | |
945 | } | |
946 | ||
947 | EXPORT_SYMBOL(iget5_locked); | |
948 | ||
949 | /** | |
950 | * iget_locked - obtain an inode from a mounted file system | |
951 | * @sb: super block of file system | |
952 | * @ino: inode number to get | |
953 | * | |
954 | * This is iget() without the read_inode() portion of get_new_inode_fast(). | |
955 | * | |
956 | * iget_locked() uses ifind_fast() to search for the inode specified by @ino in | |
957 | * the inode cache and if present it is returned with an increased reference | |
958 | * count. This is for file systems where the inode number is sufficient for | |
959 | * unique identification of an inode. | |
960 | * | |
961 | * If the inode is not in cache, get_new_inode_fast() is called to allocate a | |
962 | * new inode and this is returned locked, hashed, and with the I_NEW flag set. | |
963 | * The file system gets to fill it in before unlocking it via | |
964 | * unlock_new_inode(). | |
965 | */ | |
966 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) | |
967 | { | |
968 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
969 | struct inode *inode; | |
970 | ||
971 | inode = ifind_fast(sb, head, ino); | |
972 | if (inode) | |
973 | return inode; | |
974 | /* | |
975 | * get_new_inode_fast() will do the right thing, re-trying the search | |
976 | * in case it had to block at any point. | |
977 | */ | |
978 | return get_new_inode_fast(sb, head, ino); | |
979 | } | |
980 | ||
981 | EXPORT_SYMBOL(iget_locked); | |
982 | ||
983 | /** | |
984 | * __insert_inode_hash - hash an inode | |
985 | * @inode: unhashed inode | |
986 | * @hashval: unsigned long value used to locate this object in the | |
987 | * inode_hashtable. | |
988 | * | |
989 | * Add an inode to the inode hash for this superblock. | |
990 | */ | |
991 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) | |
992 | { | |
993 | struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); | |
994 | spin_lock(&inode_lock); | |
995 | hlist_add_head(&inode->i_hash, head); | |
996 | spin_unlock(&inode_lock); | |
997 | } | |
998 | ||
999 | EXPORT_SYMBOL(__insert_inode_hash); | |
1000 | ||
1001 | /** | |
1002 | * remove_inode_hash - remove an inode from the hash | |
1003 | * @inode: inode to unhash | |
1004 | * | |
1005 | * Remove an inode from the superblock. | |
1006 | */ | |
1007 | void remove_inode_hash(struct inode *inode) | |
1008 | { | |
1009 | spin_lock(&inode_lock); | |
1010 | hlist_del_init(&inode->i_hash); | |
1011 | spin_unlock(&inode_lock); | |
1012 | } | |
1013 | ||
1014 | EXPORT_SYMBOL(remove_inode_hash); | |
1015 | ||
1016 | /* | |
1017 | * Tell the filesystem that this inode is no longer of any interest and should | |
1018 | * be completely destroyed. | |
1019 | * | |
1020 | * We leave the inode in the inode hash table until *after* the filesystem's | |
1021 | * ->delete_inode completes. This ensures that an iget (such as nfsd might | |
1022 | * instigate) will always find up-to-date information either in the hash or on | |
1023 | * disk. | |
1024 | * | |
1025 | * I_FREEING is set so that no-one will take a new reference to the inode while | |
1026 | * it is being deleted. | |
1027 | */ | |
1028 | void generic_delete_inode(struct inode *inode) | |
1029 | { | |
1030 | struct super_operations *op = inode->i_sb->s_op; | |
1031 | ||
1032 | list_del_init(&inode->i_list); | |
1033 | list_del_init(&inode->i_sb_list); | |
1034 | inode->i_state|=I_FREEING; | |
1035 | inodes_stat.nr_inodes--; | |
1036 | spin_unlock(&inode_lock); | |
1037 | ||
1da177e4 LT |
1038 | security_inode_delete(inode); |
1039 | ||
1040 | if (op->delete_inode) { | |
1041 | void (*delete)(struct inode *) = op->delete_inode; | |
1042 | if (!is_bad_inode(inode)) | |
1043 | DQUOT_INIT(inode); | |
e85b5652 MF |
1044 | /* Filesystems implementing their own |
1045 | * s_op->delete_inode are required to call | |
1046 | * truncate_inode_pages and clear_inode() | |
1047 | * internally */ | |
1da177e4 | 1048 | delete(inode); |
e85b5652 MF |
1049 | } else { |
1050 | truncate_inode_pages(&inode->i_data, 0); | |
1da177e4 | 1051 | clear_inode(inode); |
e85b5652 | 1052 | } |
1da177e4 LT |
1053 | spin_lock(&inode_lock); |
1054 | hlist_del_init(&inode->i_hash); | |
1055 | spin_unlock(&inode_lock); | |
1056 | wake_up_inode(inode); | |
1057 | if (inode->i_state != I_CLEAR) | |
1058 | BUG(); | |
1059 | destroy_inode(inode); | |
1060 | } | |
1061 | ||
1062 | EXPORT_SYMBOL(generic_delete_inode); | |
1063 | ||
1064 | static void generic_forget_inode(struct inode *inode) | |
1065 | { | |
1066 | struct super_block *sb = inode->i_sb; | |
1067 | ||
1068 | if (!hlist_unhashed(&inode->i_hash)) { | |
1069 | if (!(inode->i_state & (I_DIRTY|I_LOCK))) | |
1070 | list_move(&inode->i_list, &inode_unused); | |
1071 | inodes_stat.nr_unused++; | |
991114c6 AV |
1072 | if (!sb || (sb->s_flags & MS_ACTIVE)) { |
1073 | spin_unlock(&inode_lock); | |
1da177e4 | 1074 | return; |
991114c6 AV |
1075 | } |
1076 | inode->i_state |= I_WILL_FREE; | |
1077 | spin_unlock(&inode_lock); | |
1da177e4 LT |
1078 | write_inode_now(inode, 1); |
1079 | spin_lock(&inode_lock); | |
991114c6 | 1080 | inode->i_state &= ~I_WILL_FREE; |
1da177e4 LT |
1081 | inodes_stat.nr_unused--; |
1082 | hlist_del_init(&inode->i_hash); | |
1083 | } | |
1084 | list_del_init(&inode->i_list); | |
1085 | list_del_init(&inode->i_sb_list); | |
991114c6 | 1086 | inode->i_state |= I_FREEING; |
1da177e4 LT |
1087 | inodes_stat.nr_inodes--; |
1088 | spin_unlock(&inode_lock); | |
1089 | if (inode->i_data.nrpages) | |
1090 | truncate_inode_pages(&inode->i_data, 0); | |
1091 | clear_inode(inode); | |
7f04c26d | 1092 | wake_up_inode(inode); |
1da177e4 LT |
1093 | destroy_inode(inode); |
1094 | } | |
1095 | ||
1096 | /* | |
1097 | * Normal UNIX filesystem behaviour: delete the | |
1098 | * inode when the usage count drops to zero, and | |
1099 | * i_nlink is zero. | |
1100 | */ | |
cb2c0233 | 1101 | void generic_drop_inode(struct inode *inode) |
1da177e4 LT |
1102 | { |
1103 | if (!inode->i_nlink) | |
1104 | generic_delete_inode(inode); | |
1105 | else | |
1106 | generic_forget_inode(inode); | |
1107 | } | |
1108 | ||
cb2c0233 MF |
1109 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1110 | ||
1da177e4 LT |
1111 | /* |
1112 | * Called when we're dropping the last reference | |
1113 | * to an inode. | |
1114 | * | |
1115 | * Call the FS "drop()" function, defaulting to | |
1116 | * the legacy UNIX filesystem behaviour.. | |
1117 | * | |
1118 | * NOTE! NOTE! NOTE! We're called with the inode lock | |
1119 | * held, and the drop function is supposed to release | |
1120 | * the lock! | |
1121 | */ | |
1122 | static inline void iput_final(struct inode *inode) | |
1123 | { | |
1124 | struct super_operations *op = inode->i_sb->s_op; | |
1125 | void (*drop)(struct inode *) = generic_drop_inode; | |
1126 | ||
1127 | if (op && op->drop_inode) | |
1128 | drop = op->drop_inode; | |
1129 | drop(inode); | |
1130 | } | |
1131 | ||
1132 | /** | |
1133 | * iput - put an inode | |
1134 | * @inode: inode to put | |
1135 | * | |
1136 | * Puts an inode, dropping its usage count. If the inode use count hits | |
1137 | * zero, the inode is then freed and may also be destroyed. | |
1138 | * | |
1139 | * Consequently, iput() can sleep. | |
1140 | */ | |
1141 | void iput(struct inode *inode) | |
1142 | { | |
1143 | if (inode) { | |
1144 | struct super_operations *op = inode->i_sb->s_op; | |
1145 | ||
1146 | BUG_ON(inode->i_state == I_CLEAR); | |
1147 | ||
1148 | if (op && op->put_inode) | |
1149 | op->put_inode(inode); | |
1150 | ||
1151 | if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) | |
1152 | iput_final(inode); | |
1153 | } | |
1154 | } | |
1155 | ||
1156 | EXPORT_SYMBOL(iput); | |
1157 | ||
1158 | /** | |
1159 | * bmap - find a block number in a file | |
1160 | * @inode: inode of file | |
1161 | * @block: block to find | |
1162 | * | |
1163 | * Returns the block number on the device holding the inode that | |
1164 | * is the disk block number for the block of the file requested. | |
1165 | * That is, asked for block 4 of inode 1 the function will return the | |
1166 | * disk block relative to the disk start that holds that block of the | |
1167 | * file. | |
1168 | */ | |
1169 | sector_t bmap(struct inode * inode, sector_t block) | |
1170 | { | |
1171 | sector_t res = 0; | |
1172 | if (inode->i_mapping->a_ops->bmap) | |
1173 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); | |
1174 | return res; | |
1175 | } | |
1176 | ||
1177 | EXPORT_SYMBOL(bmap); | |
1178 | ||
1179 | /** | |
869243a0 CH |
1180 | * touch_atime - update the access time |
1181 | * @mnt: mount the inode is accessed on | |
7045f37b | 1182 | * @dentry: dentry accessed |
1da177e4 LT |
1183 | * |
1184 | * Update the accessed time on an inode and mark it for writeback. | |
1185 | * This function automatically handles read only file systems and media, | |
1186 | * as well as the "noatime" flag and inode specific "noatime" markers. | |
1187 | */ | |
869243a0 | 1188 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1da177e4 | 1189 | { |
869243a0 | 1190 | struct inode *inode = dentry->d_inode; |
1da177e4 LT |
1191 | struct timespec now; |
1192 | ||
fc33a7bb | 1193 | if (IS_RDONLY(inode)) |
1da177e4 | 1194 | return; |
fc33a7bb CH |
1195 | |
1196 | if ((inode->i_flags & S_NOATIME) || | |
1197 | (inode->i_sb->s_flags & MS_NOATIME) || | |
1198 | ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))) | |
1da177e4 | 1199 | return; |
fc33a7bb CH |
1200 | |
1201 | /* | |
1202 | * We may have a NULL vfsmount when coming from NFSD | |
1203 | */ | |
1204 | if (mnt && | |
1205 | ((mnt->mnt_flags & MNT_NOATIME) || | |
1206 | ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))) | |
1da177e4 LT |
1207 | return; |
1208 | ||
1209 | now = current_fs_time(inode->i_sb); | |
1210 | if (!timespec_equal(&inode->i_atime, &now)) { | |
1211 | inode->i_atime = now; | |
1212 | mark_inode_dirty_sync(inode); | |
1da177e4 LT |
1213 | } |
1214 | } | |
1215 | ||
869243a0 | 1216 | EXPORT_SYMBOL(touch_atime); |
1da177e4 LT |
1217 | |
1218 | /** | |
870f4817 CH |
1219 | * file_update_time - update mtime and ctime time |
1220 | * @file: file accessed | |
1da177e4 | 1221 | * |
870f4817 CH |
1222 | * Update the mtime and ctime members of an inode and mark the inode |
1223 | * for writeback. Note that this function is meant exclusively for | |
1224 | * usage in the file write path of filesystems, and filesystems may | |
1225 | * choose to explicitly ignore update via this function with the | |
1226 | * S_NOCTIME inode flag, e.g. for network filesystem where these | |
1227 | * timestamps are handled by the server. | |
1da177e4 LT |
1228 | */ |
1229 | ||
870f4817 | 1230 | void file_update_time(struct file *file) |
1da177e4 | 1231 | { |
870f4817 | 1232 | struct inode *inode = file->f_dentry->d_inode; |
1da177e4 LT |
1233 | struct timespec now; |
1234 | int sync_it = 0; | |
1235 | ||
1236 | if (IS_NOCMTIME(inode)) | |
1237 | return; | |
1238 | if (IS_RDONLY(inode)) | |
1239 | return; | |
1240 | ||
1241 | now = current_fs_time(inode->i_sb); | |
1242 | if (!timespec_equal(&inode->i_mtime, &now)) | |
1243 | sync_it = 1; | |
1244 | inode->i_mtime = now; | |
1245 | ||
870f4817 CH |
1246 | if (!timespec_equal(&inode->i_ctime, &now)) |
1247 | sync_it = 1; | |
1248 | inode->i_ctime = now; | |
1249 | ||
1da177e4 LT |
1250 | if (sync_it) |
1251 | mark_inode_dirty_sync(inode); | |
1252 | } | |
1253 | ||
870f4817 | 1254 | EXPORT_SYMBOL(file_update_time); |
1da177e4 LT |
1255 | |
1256 | int inode_needs_sync(struct inode *inode) | |
1257 | { | |
1258 | if (IS_SYNC(inode)) | |
1259 | return 1; | |
1260 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) | |
1261 | return 1; | |
1262 | return 0; | |
1263 | } | |
1264 | ||
1265 | EXPORT_SYMBOL(inode_needs_sync); | |
1266 | ||
1267 | /* | |
1268 | * Quota functions that want to walk the inode lists.. | |
1269 | */ | |
1270 | #ifdef CONFIG_QUOTA | |
1271 | ||
1272 | /* Function back in dquot.c */ | |
1273 | int remove_inode_dquot_ref(struct inode *, int, struct list_head *); | |
1274 | ||
1275 | void remove_dquot_ref(struct super_block *sb, int type, | |
1276 | struct list_head *tofree_head) | |
1277 | { | |
1278 | struct inode *inode; | |
1279 | ||
1280 | if (!sb->dq_op) | |
1281 | return; /* nothing to do */ | |
1282 | spin_lock(&inode_lock); /* This lock is for inodes code */ | |
1283 | ||
1284 | /* | |
1285 | * We don't have to lock against quota code - test IS_QUOTAINIT is | |
1286 | * just for speedup... | |
1287 | */ | |
1288 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) | |
1289 | if (!IS_NOQUOTA(inode)) | |
1290 | remove_inode_dquot_ref(inode, type, tofree_head); | |
1291 | ||
1292 | spin_unlock(&inode_lock); | |
1293 | } | |
1294 | ||
1295 | #endif | |
1296 | ||
1297 | int inode_wait(void *word) | |
1298 | { | |
1299 | schedule(); | |
1300 | return 0; | |
1301 | } | |
1302 | ||
1303 | /* | |
168a9fd6 MS |
1304 | * If we try to find an inode in the inode hash while it is being |
1305 | * deleted, we have to wait until the filesystem completes its | |
1306 | * deletion before reporting that it isn't found. This function waits | |
1307 | * until the deletion _might_ have completed. Callers are responsible | |
1308 | * to recheck inode state. | |
1309 | * | |
1310 | * It doesn't matter if I_LOCK is not set initially, a call to | |
1311 | * wake_up_inode() after removing from the hash list will DTRT. | |
1312 | * | |
1da177e4 LT |
1313 | * This is called with inode_lock held. |
1314 | */ | |
1315 | static void __wait_on_freeing_inode(struct inode *inode) | |
1316 | { | |
1317 | wait_queue_head_t *wq; | |
1318 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK); | |
1da177e4 LT |
1319 | wq = bit_waitqueue(&inode->i_state, __I_LOCK); |
1320 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); | |
1321 | spin_unlock(&inode_lock); | |
1322 | schedule(); | |
1323 | finish_wait(wq, &wait.wait); | |
1324 | spin_lock(&inode_lock); | |
1325 | } | |
1326 | ||
1327 | void wake_up_inode(struct inode *inode) | |
1328 | { | |
1329 | /* | |
1330 | * Prevent speculative execution through spin_unlock(&inode_lock); | |
1331 | */ | |
1332 | smp_mb(); | |
1333 | wake_up_bit(&inode->i_state, __I_LOCK); | |
1334 | } | |
1335 | ||
1336 | static __initdata unsigned long ihash_entries; | |
1337 | static int __init set_ihash_entries(char *str) | |
1338 | { | |
1339 | if (!str) | |
1340 | return 0; | |
1341 | ihash_entries = simple_strtoul(str, &str, 0); | |
1342 | return 1; | |
1343 | } | |
1344 | __setup("ihash_entries=", set_ihash_entries); | |
1345 | ||
1346 | /* | |
1347 | * Initialize the waitqueues and inode hash table. | |
1348 | */ | |
1349 | void __init inode_init_early(void) | |
1350 | { | |
1351 | int loop; | |
1352 | ||
1353 | /* If hashes are distributed across NUMA nodes, defer | |
1354 | * hash allocation until vmalloc space is available. | |
1355 | */ | |
1356 | if (hashdist) | |
1357 | return; | |
1358 | ||
1359 | inode_hashtable = | |
1360 | alloc_large_system_hash("Inode-cache", | |
1361 | sizeof(struct hlist_head), | |
1362 | ihash_entries, | |
1363 | 14, | |
1364 | HASH_EARLY, | |
1365 | &i_hash_shift, | |
1366 | &i_hash_mask, | |
1367 | 0); | |
1368 | ||
1369 | for (loop = 0; loop < (1 << i_hash_shift); loop++) | |
1370 | INIT_HLIST_HEAD(&inode_hashtable[loop]); | |
1371 | } | |
1372 | ||
1373 | void __init inode_init(unsigned long mempages) | |
1374 | { | |
1375 | int loop; | |
1376 | ||
1377 | /* inode slab cache */ | |
1378 | inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode), | |
e422fd2c | 1379 | 0, SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, init_once, NULL); |
1da177e4 LT |
1380 | set_shrinker(DEFAULT_SEEKS, shrink_icache_memory); |
1381 | ||
1382 | /* Hash may have been set up in inode_init_early */ | |
1383 | if (!hashdist) | |
1384 | return; | |
1385 | ||
1386 | inode_hashtable = | |
1387 | alloc_large_system_hash("Inode-cache", | |
1388 | sizeof(struct hlist_head), | |
1389 | ihash_entries, | |
1390 | 14, | |
1391 | 0, | |
1392 | &i_hash_shift, | |
1393 | &i_hash_mask, | |
1394 | 0); | |
1395 | ||
1396 | for (loop = 0; loop < (1 << i_hash_shift); loop++) | |
1397 | INIT_HLIST_HEAD(&inode_hashtable[loop]); | |
1398 | } | |
1399 | ||
1400 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) | |
1401 | { | |
1402 | inode->i_mode = mode; | |
1403 | if (S_ISCHR(mode)) { | |
1404 | inode->i_fop = &def_chr_fops; | |
1405 | inode->i_rdev = rdev; | |
1406 | } else if (S_ISBLK(mode)) { | |
1407 | inode->i_fop = &def_blk_fops; | |
1408 | inode->i_rdev = rdev; | |
1409 | } else if (S_ISFIFO(mode)) | |
1410 | inode->i_fop = &def_fifo_fops; | |
1411 | else if (S_ISSOCK(mode)) | |
1412 | inode->i_fop = &bad_sock_fops; | |
1413 | else | |
1414 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n", | |
1415 | mode); | |
1416 | } | |
1417 | EXPORT_SYMBOL(init_special_inode); |