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1 | /* |
2 | * linux/fs/inode.c |
3 | * |
4 | * (C) 1997 Linus Torvalds |
5 | */ |
6 | |
7 | #include <linux/fs.h> |
8 | #include <linux/mm.h> |
9 | #include <linux/dcache.h> |
10 | #include <linux/init.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/writeback.h> |
13 | #include <linux/module.h> |
14 | #include <linux/backing-dev.h> |
15 | #include <linux/wait.h> |
16 | #include <linux/rwsem.h> |
17 | #include <linux/hash.h> |
18 | #include <linux/swap.h> |
19 | #include <linux/security.h> |
20 | #include <linux/pagemap.h> |
21 | #include <linux/cdev.h> |
22 | #include <linux/bootmem.h> |
23 | #include <linux/inotify.h> |
24 | #include <linux/fsnotify.h> |
25 | #include <linux/mount.h> |
26 | #include <linux/async.h> |
27 | #include <linux/posix_acl.h> |
28 | |
29 | /* |
30 | * This is needed for the following functions: |
31 | * - inode_has_buffers |
32 | * - invalidate_inode_buffers |
33 | * - invalidate_bdev |
34 | * |
35 | * FIXME: remove all knowledge of the buffer layer from this file |
36 | */ |
37 | #include <linux/buffer_head.h> |
38 | |
39 | /* |
40 | * New inode.c implementation. |
41 | * |
42 | * This implementation has the basic premise of trying |
43 | * to be extremely low-overhead and SMP-safe, yet be |
44 | * simple enough to be "obviously correct". |
45 | * |
46 | * Famous last words. |
47 | */ |
48 | |
49 | /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */ |
50 | |
51 | /* #define INODE_PARANOIA 1 */ |
52 | /* #define INODE_DEBUG 1 */ |
53 | |
54 | /* |
55 | * Inode lookup is no longer as critical as it used to be: |
56 | * most of the lookups are going to be through the dcache. |
57 | */ |
58 | #define I_HASHBITS i_hash_shift |
59 | #define I_HASHMASK i_hash_mask |
60 | |
61 | static unsigned int i_hash_mask __read_mostly; |
62 | static unsigned int i_hash_shift __read_mostly; |
63 | |
64 | /* |
65 | * Each inode can be on two separate lists. One is |
66 | * the hash list of the inode, used for lookups. The |
67 | * other linked list is the "type" list: |
68 | * "in_use" - valid inode, i_count > 0, i_nlink > 0 |
69 | * "dirty" - as "in_use" but also dirty |
70 | * "unused" - valid inode, i_count = 0 |
71 | * |
72 | * A "dirty" list is maintained for each super block, |
73 | * allowing for low-overhead inode sync() operations. |
74 | */ |
75 | |
76 | LIST_HEAD(inode_in_use); |
77 | LIST_HEAD(inode_unused); |
78 | static struct hlist_head *inode_hashtable __read_mostly; |
79 | |
80 | /* |
81 | * A simple spinlock to protect the list manipulations. |
82 | * |
83 | * NOTE! You also have to own the lock if you change |
84 | * the i_state of an inode while it is in use.. |
85 | */ |
86 | DEFINE_SPINLOCK(inode_lock); |
87 | |
88 | /* |
89 | * iprune_sem provides exclusion between the kswapd or try_to_free_pages |
90 | * icache shrinking path, and the umount path. Without this exclusion, |
91 | * by the time prune_icache calls iput for the inode whose pages it has |
92 | * been invalidating, or by the time it calls clear_inode & destroy_inode |
93 | * from its final dispose_list, the struct super_block they refer to |
94 | * (for inode->i_sb->s_op) may already have been freed and reused. |
95 | * |
96 | * We make this an rwsem because the fastpath is icache shrinking. In |
97 | * some cases a filesystem may be doing a significant amount of work in |
98 | * its inode reclaim code, so this should improve parallelism. |
99 | */ |
100 | static DECLARE_RWSEM(iprune_sem); |
101 | |
102 | /* |
103 | * Statistics gathering.. |
104 | */ |
105 | struct inodes_stat_t inodes_stat; |
106 | |
107 | static struct kmem_cache *inode_cachep __read_mostly; |
108 | |
109 | static void wake_up_inode(struct inode *inode) |
110 | { |
111 | /* |
112 | * Prevent speculative execution through spin_unlock(&inode_lock); |
113 | */ |
114 | smp_mb(); |
115 | wake_up_bit(&inode->i_state, __I_NEW); |
116 | } |
117 | |
118 | /** |
119 | * inode_init_always - perform inode structure intialisation |
120 | * @sb: superblock inode belongs to |
121 | * @inode: inode to initialise |
122 | * |
123 | * These are initializations that need to be done on every inode |
124 | * allocation as the fields are not initialised by slab allocation. |
125 | */ |
126 | int inode_init_always(struct super_block *sb, struct inode *inode) |
127 | { |
128 | static const struct address_space_operations empty_aops; |
129 | static const struct inode_operations empty_iops; |
130 | static const struct file_operations empty_fops; |
131 | struct address_space *const mapping = &inode->i_data; |
132 | |
133 | inode->i_sb = sb; |
134 | inode->i_blkbits = sb->s_blocksize_bits; |
135 | inode->i_flags = 0; |
136 | atomic_set(&inode->i_count, 1); |
137 | inode->i_op = &empty_iops; |
138 | inode->i_fop = &empty_fops; |
139 | inode->i_nlink = 1; |
140 | inode->i_uid = 0; |
141 | inode->i_gid = 0; |
142 | atomic_set(&inode->i_writecount, 0); |
143 | inode->i_size = 0; |
144 | inode->i_blocks = 0; |
145 | inode->i_bytes = 0; |
146 | inode->i_generation = 0; |
147 | #ifdef CONFIG_QUOTA |
148 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
149 | #endif |
150 | inode->i_pipe = NULL; |
151 | inode->i_bdev = NULL; |
152 | inode->i_cdev = NULL; |
153 | inode->i_rdev = 0; |
154 | inode->dirtied_when = 0; |
155 | |
156 | if (security_inode_alloc(inode)) |
157 | goto out; |
158 | spin_lock_init(&inode->i_lock); |
159 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
160 | |
161 | mutex_init(&inode->i_mutex); |
162 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
163 | |
164 | init_rwsem(&inode->i_alloc_sem); |
165 | lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); |
166 | |
167 | mapping->a_ops = &empty_aops; |
168 | mapping->host = inode; |
169 | mapping->flags = 0; |
170 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
171 | mapping->assoc_mapping = NULL; |
172 | mapping->backing_dev_info = &default_backing_dev_info; |
173 | mapping->writeback_index = 0; |
174 | |
175 | /* |
176 | * If the block_device provides a backing_dev_info for client |
177 | * inodes then use that. Otherwise the inode share the bdev's |
178 | * backing_dev_info. |
179 | */ |
180 | if (sb->s_bdev) { |
181 | struct backing_dev_info *bdi; |
182 | |
183 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
184 | mapping->backing_dev_info = bdi; |
185 | } |
186 | inode->i_private = NULL; |
187 | inode->i_mapping = mapping; |
188 | #ifdef CONFIG_FS_POSIX_ACL |
189 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
190 | #endif |
191 | |
192 | #ifdef CONFIG_FSNOTIFY |
193 | inode->i_fsnotify_mask = 0; |
194 | #endif |
195 | |
196 | return 0; |
197 | out: |
198 | return -ENOMEM; |
199 | } |
200 | EXPORT_SYMBOL(inode_init_always); |
201 | |
202 | static struct inode *alloc_inode(struct super_block *sb) |
203 | { |
204 | struct inode *inode; |
205 | |
206 | if (sb->s_op->alloc_inode) |
207 | inode = sb->s_op->alloc_inode(sb); |
208 | else |
209 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
210 | |
211 | if (!inode) |
212 | return NULL; |
213 | |
214 | if (unlikely(inode_init_always(sb, inode))) { |
215 | if (inode->i_sb->s_op->destroy_inode) |
216 | inode->i_sb->s_op->destroy_inode(inode); |
217 | else |
218 | kmem_cache_free(inode_cachep, inode); |
219 | return NULL; |
220 | } |
221 | |
222 | return inode; |
223 | } |
224 | |
225 | void __destroy_inode(struct inode *inode) |
226 | { |
227 | BUG_ON(inode_has_buffers(inode)); |
228 | security_inode_free(inode); |
229 | fsnotify_inode_delete(inode); |
230 | #ifdef CONFIG_FS_POSIX_ACL |
231 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
232 | posix_acl_release(inode->i_acl); |
233 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
234 | posix_acl_release(inode->i_default_acl); |
235 | #endif |
236 | } |
237 | EXPORT_SYMBOL(__destroy_inode); |
238 | |
239 | void destroy_inode(struct inode *inode) |
240 | { |
241 | __destroy_inode(inode); |
242 | if (inode->i_sb->s_op->destroy_inode) |
243 | inode->i_sb->s_op->destroy_inode(inode); |
244 | else |
245 | kmem_cache_free(inode_cachep, (inode)); |
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); |
259 | INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); |
260 | spin_lock_init(&inode->i_data.tree_lock); |
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); |
266 | i_size_ordered_init(inode); |
267 | #ifdef CONFIG_INOTIFY |
268 | INIT_LIST_HEAD(&inode->inotify_watches); |
269 | mutex_init(&inode->inotify_mutex); |
270 | #endif |
271 | #ifdef CONFIG_FSNOTIFY |
272 | INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries); |
273 | #endif |
274 | } |
275 | EXPORT_SYMBOL(inode_init_once); |
276 | |
277 | static void init_once(void *foo) |
278 | { |
279 | struct inode *inode = (struct inode *) foo; |
280 | |
281 | inode_init_once(inode); |
282 | } |
283 | |
284 | /* |
285 | * inode_lock must be held |
286 | */ |
287 | void __iget(struct inode *inode) |
288 | { |
289 | if (atomic_read(&inode->i_count)) { |
290 | atomic_inc(&inode->i_count); |
291 | return; |
292 | } |
293 | atomic_inc(&inode->i_count); |
294 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
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); |
311 | |
312 | BUG_ON(inode->i_data.nrpages); |
313 | BUG_ON(!(inode->i_state & I_FREEING)); |
314 | BUG_ON(inode->i_state & I_CLEAR); |
315 | inode_sync_wait(inode); |
316 | if (inode->i_sb->s_op->clear_inode) |
317 | inode->i_sb->s_op->clear_inode(inode); |
318 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
319 | bd_forget(inode); |
320 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
321 | cd_forget(inode); |
322 | inode->i_state = I_CLEAR; |
323 | } |
324 | EXPORT_SYMBOL(clear_inode); |
325 | |
326 | /* |
327 | * dispose_list - dispose of the contents of a local list |
328 | * @head: the head of the list to free |
329 | * |
330 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
331 | * need to worry about list corruption and SMP locks. |
332 | */ |
333 | static void dispose_list(struct list_head *head) |
334 | { |
335 | int nr_disposed = 0; |
336 | |
337 | while (!list_empty(head)) { |
338 | struct inode *inode; |
339 | |
340 | inode = list_first_entry(head, struct inode, i_list); |
341 | list_del(&inode->i_list); |
342 | |
343 | if (inode->i_data.nrpages) |
344 | truncate_inode_pages(&inode->i_data, 0); |
345 | clear_inode(inode); |
346 | |
347 | spin_lock(&inode_lock); |
348 | hlist_del_init(&inode->i_hash); |
349 | list_del_init(&inode->i_sb_list); |
350 | spin_unlock(&inode_lock); |
351 | |
352 | wake_up_inode(inode); |
353 | destroy_inode(inode); |
354 | nr_disposed++; |
355 | } |
356 | spin_lock(&inode_lock); |
357 | inodes_stat.nr_inodes -= nr_disposed; |
358 | spin_unlock(&inode_lock); |
359 | } |
360 | |
361 | /* |
362 | * Invalidate all inodes for a device. |
363 | */ |
364 | static int invalidate_list(struct list_head *head, struct list_head *dispose) |
365 | { |
366 | struct list_head *next; |
367 | int busy = 0, count = 0; |
368 | |
369 | next = head->next; |
370 | for (;;) { |
371 | struct list_head *tmp = next; |
372 | struct inode *inode; |
373 | |
374 | /* |
375 | * We can reschedule here without worrying about the list's |
376 | * consistency because the per-sb list of inodes must not |
377 | * change during umount anymore, and because iprune_sem keeps |
378 | * shrink_icache_memory() away. |
379 | */ |
380 | cond_resched_lock(&inode_lock); |
381 | |
382 | next = next->next; |
383 | if (tmp == head) |
384 | break; |
385 | inode = list_entry(tmp, struct inode, i_sb_list); |
386 | if (inode->i_state & I_NEW) |
387 | continue; |
388 | invalidate_inode_buffers(inode); |
389 | if (!atomic_read(&inode->i_count)) { |
390 | list_move(&inode->i_list, dispose); |
391 | WARN_ON(inode->i_state & I_NEW); |
392 | inode->i_state |= I_FREEING; |
393 | count++; |
394 | continue; |
395 | } |
396 | busy = 1; |
397 | } |
398 | /* only unused inodes may be cached with i_count zero */ |
399 | inodes_stat.nr_unused -= count; |
400 | return busy; |
401 | } |
402 | |
403 | /** |
404 | * invalidate_inodes - discard the inodes on a device |
405 | * @sb: superblock |
406 | * |
407 | * Discard all of the inodes for a given superblock. If the discard |
408 | * fails because there are busy inodes then a non zero value is returned. |
409 | * If the discard is successful all the inodes have been discarded. |
410 | */ |
411 | int invalidate_inodes(struct super_block *sb) |
412 | { |
413 | int busy; |
414 | LIST_HEAD(throw_away); |
415 | |
416 | down_write(&iprune_sem); |
417 | spin_lock(&inode_lock); |
418 | inotify_unmount_inodes(&sb->s_inodes); |
419 | fsnotify_unmount_inodes(&sb->s_inodes); |
420 | busy = invalidate_list(&sb->s_inodes, &throw_away); |
421 | spin_unlock(&inode_lock); |
422 | |
423 | dispose_list(&throw_away); |
424 | up_write(&iprune_sem); |
425 | |
426 | return busy; |
427 | } |
428 | EXPORT_SYMBOL(invalidate_inodes); |
429 | |
430 | static int can_unuse(struct inode *inode) |
431 | { |
432 | if (inode->i_state) |
433 | return 0; |
434 | if (inode_has_buffers(inode)) |
435 | return 0; |
436 | if (atomic_read(&inode->i_count)) |
437 | return 0; |
438 | if (inode->i_data.nrpages) |
439 | return 0; |
440 | return 1; |
441 | } |
442 | |
443 | /* |
444 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to |
445 | * a temporary list and then are freed outside inode_lock by dispose_list(). |
446 | * |
447 | * Any inodes which are pinned purely because of attached pagecache have their |
448 | * pagecache removed. We expect the final iput() on that inode to add it to |
449 | * the front of the inode_unused list. So look for it there and if the |
450 | * inode is still freeable, proceed. The right inode is found 99.9% of the |
451 | * time in testing on a 4-way. |
452 | * |
453 | * If the inode has metadata buffers attached to mapping->private_list then |
454 | * try to remove them. |
455 | */ |
456 | static void prune_icache(int nr_to_scan) |
457 | { |
458 | LIST_HEAD(freeable); |
459 | int nr_pruned = 0; |
460 | int nr_scanned; |
461 | unsigned long reap = 0; |
462 | |
463 | down_read(&iprune_sem); |
464 | spin_lock(&inode_lock); |
465 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { |
466 | struct inode *inode; |
467 | |
468 | if (list_empty(&inode_unused)) |
469 | break; |
470 | |
471 | inode = list_entry(inode_unused.prev, struct inode, i_list); |
472 | |
473 | if (inode->i_state || atomic_read(&inode->i_count)) { |
474 | list_move(&inode->i_list, &inode_unused); |
475 | continue; |
476 | } |
477 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
478 | __iget(inode); |
479 | spin_unlock(&inode_lock); |
480 | if (remove_inode_buffers(inode)) |
481 | reap += invalidate_mapping_pages(&inode->i_data, |
482 | 0, -1); |
483 | iput(inode); |
484 | spin_lock(&inode_lock); |
485 | |
486 | if (inode != list_entry(inode_unused.next, |
487 | struct inode, i_list)) |
488 | continue; /* wrong inode or list_empty */ |
489 | if (!can_unuse(inode)) |
490 | continue; |
491 | } |
492 | list_move(&inode->i_list, &freeable); |
493 | WARN_ON(inode->i_state & I_NEW); |
494 | inode->i_state |= I_FREEING; |
495 | nr_pruned++; |
496 | } |
497 | inodes_stat.nr_unused -= nr_pruned; |
498 | if (current_is_kswapd()) |
499 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
500 | else |
501 | __count_vm_events(PGINODESTEAL, reap); |
502 | spin_unlock(&inode_lock); |
503 | |
504 | dispose_list(&freeable); |
505 | up_read(&iprune_sem); |
506 | } |
507 | |
508 | /* |
509 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, |
510 | * "unused" means that no dentries are referring to the inodes: the files are |
511 | * not open and the dcache references to those inodes have already been |
512 | * reclaimed. |
513 | * |
514 | * This function is passed the number of inodes to scan, and it returns the |
515 | * total number of remaining possibly-reclaimable inodes. |
516 | */ |
517 | static int shrink_icache_memory(int nr, gfp_t gfp_mask) |
518 | { |
519 | if (nr) { |
520 | /* |
521 | * Nasty deadlock avoidance. We may hold various FS locks, |
522 | * and we don't want to recurse into the FS that called us |
523 | * in clear_inode() and friends.. |
524 | */ |
525 | if (!(gfp_mask & __GFP_FS)) |
526 | return -1; |
527 | prune_icache(nr); |
528 | } |
529 | return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; |
530 | } |
531 | |
532 | static struct shrinker icache_shrinker = { |
533 | .shrink = shrink_icache_memory, |
534 | .seeks = DEFAULT_SEEKS, |
535 | }; |
536 | |
537 | static void __wait_on_freeing_inode(struct inode *inode); |
538 | /* |
539 | * Called with the inode lock held. |
540 | * NOTE: we are not increasing the inode-refcount, you must call __iget() |
541 | * by hand after calling find_inode now! This simplifies iunique and won't |
542 | * add any additional branch in the common code. |
543 | */ |
544 | static struct inode *find_inode(struct super_block *sb, |
545 | struct hlist_head *head, |
546 | int (*test)(struct inode *, void *), |
547 | void *data) |
548 | { |
549 | struct hlist_node *node; |
550 | struct inode *inode = NULL; |
551 | |
552 | repeat: |
553 | hlist_for_each_entry(inode, node, head, i_hash) { |
554 | if (inode->i_sb != sb) |
555 | continue; |
556 | if (!test(inode, data)) |
557 | continue; |
558 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
559 | __wait_on_freeing_inode(inode); |
560 | goto repeat; |
561 | } |
562 | break; |
563 | } |
564 | return node ? inode : NULL; |
565 | } |
566 | |
567 | /* |
568 | * find_inode_fast is the fast path version of find_inode, see the comment at |
569 | * iget_locked for details. |
570 | */ |
571 | static struct inode *find_inode_fast(struct super_block *sb, |
572 | struct hlist_head *head, unsigned long ino) |
573 | { |
574 | struct hlist_node *node; |
575 | struct inode *inode = NULL; |
576 | |
577 | repeat: |
578 | hlist_for_each_entry(inode, node, head, i_hash) { |
579 | if (inode->i_ino != ino) |
580 | continue; |
581 | if (inode->i_sb != sb) |
582 | continue; |
583 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
584 | __wait_on_freeing_inode(inode); |
585 | goto repeat; |
586 | } |
587 | break; |
588 | } |
589 | return node ? inode : NULL; |
590 | } |
591 | |
592 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
593 | { |
594 | unsigned long tmp; |
595 | |
596 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
597 | L1_CACHE_BYTES; |
598 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); |
599 | return tmp & I_HASHMASK; |
600 | } |
601 | |
602 | static inline void |
603 | __inode_add_to_lists(struct super_block *sb, struct hlist_head *head, |
604 | struct inode *inode) |
605 | { |
606 | inodes_stat.nr_inodes++; |
607 | list_add(&inode->i_list, &inode_in_use); |
608 | list_add(&inode->i_sb_list, &sb->s_inodes); |
609 | if (head) |
610 | hlist_add_head(&inode->i_hash, head); |
611 | } |
612 | |
613 | /** |
614 | * inode_add_to_lists - add a new inode to relevant lists |
615 | * @sb: superblock inode belongs to |
616 | * @inode: inode to mark in use |
617 | * |
618 | * When an inode is allocated it needs to be accounted for, added to the in use |
619 | * list, the owning superblock and the inode hash. This needs to be done under |
620 | * the inode_lock, so export a function to do this rather than the inode lock |
621 | * itself. We calculate the hash list to add to here so it is all internal |
622 | * which requires the caller to have already set up the inode number in the |
623 | * inode to add. |
624 | */ |
625 | void inode_add_to_lists(struct super_block *sb, struct inode *inode) |
626 | { |
627 | struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino); |
628 | |
629 | spin_lock(&inode_lock); |
630 | __inode_add_to_lists(sb, head, inode); |
631 | spin_unlock(&inode_lock); |
632 | } |
633 | EXPORT_SYMBOL_GPL(inode_add_to_lists); |
634 | |
635 | /** |
636 | * new_inode - obtain an inode |
637 | * @sb: superblock |
638 | * |
639 | * Allocates a new inode for given superblock. The default gfp_mask |
640 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
641 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
642 | * for the page cache are not reclaimable or migratable, |
643 | * mapping_set_gfp_mask() must be called with suitable flags on the |
644 | * newly created inode's mapping |
645 | * |
646 | */ |
647 | struct inode *new_inode(struct super_block *sb) |
648 | { |
649 | /* |
650 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
651 | * error if st_ino won't fit in target struct field. Use 32bit counter |
652 | * here to attempt to avoid that. |
653 | */ |
654 | static unsigned int last_ino; |
655 | struct inode *inode; |
656 | |
657 | spin_lock_prefetch(&inode_lock); |
658 | |
659 | inode = alloc_inode(sb); |
660 | if (inode) { |
661 | spin_lock(&inode_lock); |
662 | __inode_add_to_lists(sb, NULL, inode); |
663 | inode->i_ino = ++last_ino; |
664 | inode->i_state = 0; |
665 | spin_unlock(&inode_lock); |
666 | } |
667 | return inode; |
668 | } |
669 | EXPORT_SYMBOL(new_inode); |
670 | |
671 | void unlock_new_inode(struct inode *inode) |
672 | { |
673 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
674 | if (inode->i_mode & S_IFDIR) { |
675 | struct file_system_type *type = inode->i_sb->s_type; |
676 | |
677 | /* Set new key only if filesystem hasn't already changed it */ |
678 | if (!lockdep_match_class(&inode->i_mutex, |
679 | &type->i_mutex_key)) { |
680 | /* |
681 | * ensure nobody is actually holding i_mutex |
682 | */ |
683 | mutex_destroy(&inode->i_mutex); |
684 | mutex_init(&inode->i_mutex); |
685 | lockdep_set_class(&inode->i_mutex, |
686 | &type->i_mutex_dir_key); |
687 | } |
688 | } |
689 | #endif |
690 | /* |
691 | * This is special! We do not need the spinlock when clearing I_NEW, |
692 | * because we're guaranteed that nobody else tries to do anything about |
693 | * the state of the inode when it is locked, as we just created it (so |
694 | * there can be no old holders that haven't tested I_NEW). |
695 | * However we must emit the memory barrier so that other CPUs reliably |
696 | * see the clearing of I_NEW after the other inode initialisation has |
697 | * completed. |
698 | */ |
699 | smp_mb(); |
700 | WARN_ON(!(inode->i_state & I_NEW)); |
701 | inode->i_state &= ~I_NEW; |
702 | wake_up_inode(inode); |
703 | } |
704 | EXPORT_SYMBOL(unlock_new_inode); |
705 | |
706 | /* |
707 | * This is called without the inode lock held.. Be careful. |
708 | * |
709 | * We no longer cache the sb_flags in i_flags - see fs.h |
710 | * -- rmk@arm.uk.linux.org |
711 | */ |
712 | static struct inode *get_new_inode(struct super_block *sb, |
713 | struct hlist_head *head, |
714 | int (*test)(struct inode *, void *), |
715 | int (*set)(struct inode *, void *), |
716 | void *data) |
717 | { |
718 | struct inode *inode; |
719 | |
720 | inode = alloc_inode(sb); |
721 | if (inode) { |
722 | struct inode *old; |
723 | |
724 | spin_lock(&inode_lock); |
725 | /* We released the lock, so.. */ |
726 | old = find_inode(sb, head, test, data); |
727 | if (!old) { |
728 | if (set(inode, data)) |
729 | goto set_failed; |
730 | |
731 | __inode_add_to_lists(sb, head, inode); |
732 | inode->i_state = I_NEW; |
733 | spin_unlock(&inode_lock); |
734 | |
735 | /* Return the locked inode with I_NEW set, the |
736 | * caller is responsible for filling in the contents |
737 | */ |
738 | return inode; |
739 | } |
740 | |
741 | /* |
742 | * Uhhuh, somebody else created the same inode under |
743 | * us. Use the old inode instead of the one we just |
744 | * allocated. |
745 | */ |
746 | __iget(old); |
747 | spin_unlock(&inode_lock); |
748 | destroy_inode(inode); |
749 | inode = old; |
750 | wait_on_inode(inode); |
751 | } |
752 | return inode; |
753 | |
754 | set_failed: |
755 | spin_unlock(&inode_lock); |
756 | destroy_inode(inode); |
757 | return NULL; |
758 | } |
759 | |
760 | /* |
761 | * get_new_inode_fast is the fast path version of get_new_inode, see the |
762 | * comment at iget_locked for details. |
763 | */ |
764 | static struct inode *get_new_inode_fast(struct super_block *sb, |
765 | struct hlist_head *head, unsigned long ino) |
766 | { |
767 | struct inode *inode; |
768 | |
769 | inode = alloc_inode(sb); |
770 | if (inode) { |
771 | struct inode *old; |
772 | |
773 | spin_lock(&inode_lock); |
774 | /* We released the lock, so.. */ |
775 | old = find_inode_fast(sb, head, ino); |
776 | if (!old) { |
777 | inode->i_ino = ino; |
778 | __inode_add_to_lists(sb, head, inode); |
779 | inode->i_state = I_NEW; |
780 | spin_unlock(&inode_lock); |
781 | |
782 | /* Return the locked inode with I_NEW set, the |
783 | * caller is responsible for filling in the contents |
784 | */ |
785 | return inode; |
786 | } |
787 | |
788 | /* |
789 | * Uhhuh, somebody else created the same inode under |
790 | * us. Use the old inode instead of the one we just |
791 | * allocated. |
792 | */ |
793 | __iget(old); |
794 | spin_unlock(&inode_lock); |
795 | destroy_inode(inode); |
796 | inode = old; |
797 | wait_on_inode(inode); |
798 | } |
799 | return inode; |
800 | } |
801 | |
802 | /** |
803 | * iunique - get a unique inode number |
804 | * @sb: superblock |
805 | * @max_reserved: highest reserved inode number |
806 | * |
807 | * Obtain an inode number that is unique on the system for a given |
808 | * superblock. This is used by file systems that have no natural |
809 | * permanent inode numbering system. An inode number is returned that |
810 | * is higher than the reserved limit but unique. |
811 | * |
812 | * BUGS: |
813 | * With a large number of inodes live on the file system this function |
814 | * currently becomes quite slow. |
815 | */ |
816 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
817 | { |
818 | /* |
819 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
820 | * error if st_ino won't fit in target struct field. Use 32bit counter |
821 | * here to attempt to avoid that. |
822 | */ |
823 | static unsigned int counter; |
824 | struct inode *inode; |
825 | struct hlist_head *head; |
826 | ino_t res; |
827 | |
828 | spin_lock(&inode_lock); |
829 | do { |
830 | if (counter <= max_reserved) |
831 | counter = max_reserved + 1; |
832 | res = counter++; |
833 | head = inode_hashtable + hash(sb, res); |
834 | inode = find_inode_fast(sb, head, res); |
835 | } while (inode != NULL); |
836 | spin_unlock(&inode_lock); |
837 | |
838 | return res; |
839 | } |
840 | EXPORT_SYMBOL(iunique); |
841 | |
842 | struct inode *igrab(struct inode *inode) |
843 | { |
844 | spin_lock(&inode_lock); |
845 | if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))) |
846 | __iget(inode); |
847 | else |
848 | /* |
849 | * Handle the case where s_op->clear_inode is not been |
850 | * called yet, and somebody is calling igrab |
851 | * while the inode is getting freed. |
852 | */ |
853 | inode = NULL; |
854 | spin_unlock(&inode_lock); |
855 | return inode; |
856 | } |
857 | EXPORT_SYMBOL(igrab); |
858 | |
859 | /** |
860 | * ifind - internal function, you want ilookup5() or iget5(). |
861 | * @sb: super block of file system to search |
862 | * @head: the head of the list to search |
863 | * @test: callback used for comparisons between inodes |
864 | * @data: opaque data pointer to pass to @test |
865 | * @wait: if true wait for the inode to be unlocked, if false do not |
866 | * |
867 | * ifind() searches for the inode specified by @data in the inode |
868 | * cache. This is a generalized version of ifind_fast() for file systems where |
869 | * the inode number is not sufficient for unique identification of an inode. |
870 | * |
871 | * If the inode is in the cache, the inode is returned with an incremented |
872 | * reference count. |
873 | * |
874 | * Otherwise NULL is returned. |
875 | * |
876 | * Note, @test is called with the inode_lock held, so can't sleep. |
877 | */ |
878 | static struct inode *ifind(struct super_block *sb, |
879 | struct hlist_head *head, int (*test)(struct inode *, void *), |
880 | void *data, const int wait) |
881 | { |
882 | struct inode *inode; |
883 | |
884 | spin_lock(&inode_lock); |
885 | inode = find_inode(sb, head, test, data); |
886 | if (inode) { |
887 | __iget(inode); |
888 | spin_unlock(&inode_lock); |
889 | if (likely(wait)) |
890 | wait_on_inode(inode); |
891 | return inode; |
892 | } |
893 | spin_unlock(&inode_lock); |
894 | return NULL; |
895 | } |
896 | |
897 | /** |
898 | * ifind_fast - internal function, you want ilookup() or iget(). |
899 | * @sb: super block of file system to search |
900 | * @head: head of the list to search |
901 | * @ino: inode number to search for |
902 | * |
903 | * ifind_fast() searches for the inode @ino in the inode cache. This is for |
904 | * file systems where the inode number is sufficient for unique identification |
905 | * of an inode. |
906 | * |
907 | * If the inode is in the cache, the inode is returned with an incremented |
908 | * reference count. |
909 | * |
910 | * Otherwise NULL is returned. |
911 | */ |
912 | static struct inode *ifind_fast(struct super_block *sb, |
913 | struct hlist_head *head, unsigned long ino) |
914 | { |
915 | struct inode *inode; |
916 | |
917 | spin_lock(&inode_lock); |
918 | inode = find_inode_fast(sb, head, ino); |
919 | if (inode) { |
920 | __iget(inode); |
921 | spin_unlock(&inode_lock); |
922 | wait_on_inode(inode); |
923 | return inode; |
924 | } |
925 | spin_unlock(&inode_lock); |
926 | return NULL; |
927 | } |
928 | |
929 | /** |
930 | * ilookup5_nowait - search for an inode in the inode cache |
931 | * @sb: super block of file system to search |
932 | * @hashval: hash value (usually inode number) to search for |
933 | * @test: callback used for comparisons between inodes |
934 | * @data: opaque data pointer to pass to @test |
935 | * |
936 | * ilookup5() uses ifind() to search for the inode specified by @hashval and |
937 | * @data in the inode cache. This is a generalized version of ilookup() for |
938 | * file systems where the inode number is not sufficient for unique |
939 | * identification of an inode. |
940 | * |
941 | * If the inode is in the cache, the inode is returned with an incremented |
942 | * reference count. Note, the inode lock is not waited upon so you have to be |
943 | * very careful what you do with the returned inode. You probably should be |
944 | * using ilookup5() instead. |
945 | * |
946 | * Otherwise NULL is returned. |
947 | * |
948 | * Note, @test is called with the inode_lock held, so can't sleep. |
949 | */ |
950 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
951 | int (*test)(struct inode *, void *), void *data) |
952 | { |
953 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
954 | |
955 | return ifind(sb, head, test, data, 0); |
956 | } |
957 | EXPORT_SYMBOL(ilookup5_nowait); |
958 | |
959 | /** |
960 | * ilookup5 - search for an inode in the inode cache |
961 | * @sb: super block of file system to search |
962 | * @hashval: hash value (usually inode number) to search for |
963 | * @test: callback used for comparisons between inodes |
964 | * @data: opaque data pointer to pass to @test |
965 | * |
966 | * ilookup5() uses ifind() to search for the inode specified by @hashval and |
967 | * @data in the inode cache. This is a generalized version of ilookup() for |
968 | * file systems where the inode number is not sufficient for unique |
969 | * identification of an inode. |
970 | * |
971 | * If the inode is in the cache, the inode lock is waited upon and the inode is |
972 | * returned with an incremented reference count. |
973 | * |
974 | * Otherwise NULL is returned. |
975 | * |
976 | * Note, @test is called with the inode_lock held, so can't sleep. |
977 | */ |
978 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
979 | int (*test)(struct inode *, void *), void *data) |
980 | { |
981 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
982 | |
983 | return ifind(sb, head, test, data, 1); |
984 | } |
985 | EXPORT_SYMBOL(ilookup5); |
986 | |
987 | /** |
988 | * ilookup - search for an inode in the inode cache |
989 | * @sb: super block of file system to search |
990 | * @ino: inode number to search for |
991 | * |
992 | * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. |
993 | * This is for file systems where the inode number is sufficient for unique |
994 | * identification of an inode. |
995 | * |
996 | * If the inode is in the cache, the inode is returned with an incremented |
997 | * reference count. |
998 | * |
999 | * Otherwise NULL is returned. |
1000 | */ |
1001 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1002 | { |
1003 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1004 | |
1005 | return ifind_fast(sb, head, ino); |
1006 | } |
1007 | EXPORT_SYMBOL(ilookup); |
1008 | |
1009 | /** |
1010 | * iget5_locked - obtain an inode from a mounted file system |
1011 | * @sb: super block of file system |
1012 | * @hashval: hash value (usually inode number) to get |
1013 | * @test: callback used for comparisons between inodes |
1014 | * @set: callback used to initialize a new struct inode |
1015 | * @data: opaque data pointer to pass to @test and @set |
1016 | * |
1017 | * iget5_locked() uses ifind() to search for the inode specified by @hashval |
1018 | * and @data in the inode cache and if present it is returned with an increased |
1019 | * reference count. This is a generalized version of iget_locked() for file |
1020 | * systems where the inode number is not sufficient for unique identification |
1021 | * of an inode. |
1022 | * |
1023 | * If the inode is not in cache, get_new_inode() is called to allocate a new |
1024 | * inode and this is returned locked, hashed, and with the I_NEW flag set. The |
1025 | * file system gets to fill it in before unlocking it via unlock_new_inode(). |
1026 | * |
1027 | * Note both @test and @set are called with the inode_lock held, so can't sleep. |
1028 | */ |
1029 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
1030 | int (*test)(struct inode *, void *), |
1031 | int (*set)(struct inode *, void *), void *data) |
1032 | { |
1033 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1034 | struct inode *inode; |
1035 | |
1036 | inode = ifind(sb, head, test, data, 1); |
1037 | if (inode) |
1038 | return inode; |
1039 | /* |
1040 | * get_new_inode() will do the right thing, re-trying the search |
1041 | * in case it had to block at any point. |
1042 | */ |
1043 | return get_new_inode(sb, head, test, set, data); |
1044 | } |
1045 | EXPORT_SYMBOL(iget5_locked); |
1046 | |
1047 | /** |
1048 | * iget_locked - obtain an inode from a mounted file system |
1049 | * @sb: super block of file system |
1050 | * @ino: inode number to get |
1051 | * |
1052 | * iget_locked() uses ifind_fast() to search for the inode specified by @ino in |
1053 | * the inode cache and if present it is returned with an increased reference |
1054 | * count. This is for file systems where the inode number is sufficient for |
1055 | * unique identification of an inode. |
1056 | * |
1057 | * If the inode is not in cache, get_new_inode_fast() is called to allocate a |
1058 | * new inode and this is returned locked, hashed, and with the I_NEW flag set. |
1059 | * The file system gets to fill it in before unlocking it via |
1060 | * unlock_new_inode(). |
1061 | */ |
1062 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1063 | { |
1064 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1065 | struct inode *inode; |
1066 | |
1067 | inode = ifind_fast(sb, head, ino); |
1068 | if (inode) |
1069 | return inode; |
1070 | /* |
1071 | * get_new_inode_fast() will do the right thing, re-trying the search |
1072 | * in case it had to block at any point. |
1073 | */ |
1074 | return get_new_inode_fast(sb, head, ino); |
1075 | } |
1076 | EXPORT_SYMBOL(iget_locked); |
1077 | |
1078 | int insert_inode_locked(struct inode *inode) |
1079 | { |
1080 | struct super_block *sb = inode->i_sb; |
1081 | ino_t ino = inode->i_ino; |
1082 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1083 | |
1084 | inode->i_state |= I_NEW; |
1085 | while (1) { |
1086 | struct hlist_node *node; |
1087 | struct inode *old = NULL; |
1088 | spin_lock(&inode_lock); |
1089 | hlist_for_each_entry(old, node, head, i_hash) { |
1090 | if (old->i_ino != ino) |
1091 | continue; |
1092 | if (old->i_sb != sb) |
1093 | continue; |
1094 | if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) |
1095 | continue; |
1096 | break; |
1097 | } |
1098 | if (likely(!node)) { |
1099 | hlist_add_head(&inode->i_hash, head); |
1100 | spin_unlock(&inode_lock); |
1101 | return 0; |
1102 | } |
1103 | __iget(old); |
1104 | spin_unlock(&inode_lock); |
1105 | wait_on_inode(old); |
1106 | if (unlikely(!hlist_unhashed(&old->i_hash))) { |
1107 | iput(old); |
1108 | return -EBUSY; |
1109 | } |
1110 | iput(old); |
1111 | } |
1112 | } |
1113 | EXPORT_SYMBOL(insert_inode_locked); |
1114 | |
1115 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1116 | int (*test)(struct inode *, void *), void *data) |
1117 | { |
1118 | struct super_block *sb = inode->i_sb; |
1119 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1120 | |
1121 | inode->i_state |= I_NEW; |
1122 | |
1123 | while (1) { |
1124 | struct hlist_node *node; |
1125 | struct inode *old = NULL; |
1126 | |
1127 | spin_lock(&inode_lock); |
1128 | hlist_for_each_entry(old, node, head, i_hash) { |
1129 | if (old->i_sb != sb) |
1130 | continue; |
1131 | if (!test(old, data)) |
1132 | continue; |
1133 | if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) |
1134 | continue; |
1135 | break; |
1136 | } |
1137 | if (likely(!node)) { |
1138 | hlist_add_head(&inode->i_hash, head); |
1139 | spin_unlock(&inode_lock); |
1140 | return 0; |
1141 | } |
1142 | __iget(old); |
1143 | spin_unlock(&inode_lock); |
1144 | wait_on_inode(old); |
1145 | if (unlikely(!hlist_unhashed(&old->i_hash))) { |
1146 | iput(old); |
1147 | return -EBUSY; |
1148 | } |
1149 | iput(old); |
1150 | } |
1151 | } |
1152 | EXPORT_SYMBOL(insert_inode_locked4); |
1153 | |
1154 | /** |
1155 | * __insert_inode_hash - hash an inode |
1156 | * @inode: unhashed inode |
1157 | * @hashval: unsigned long value used to locate this object in the |
1158 | * inode_hashtable. |
1159 | * |
1160 | * Add an inode to the inode hash for this superblock. |
1161 | */ |
1162 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
1163 | { |
1164 | struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); |
1165 | spin_lock(&inode_lock); |
1166 | hlist_add_head(&inode->i_hash, head); |
1167 | spin_unlock(&inode_lock); |
1168 | } |
1169 | EXPORT_SYMBOL(__insert_inode_hash); |
1170 | |
1171 | /** |
1172 | * remove_inode_hash - remove an inode from the hash |
1173 | * @inode: inode to unhash |
1174 | * |
1175 | * Remove an inode from the superblock. |
1176 | */ |
1177 | void remove_inode_hash(struct inode *inode) |
1178 | { |
1179 | spin_lock(&inode_lock); |
1180 | hlist_del_init(&inode->i_hash); |
1181 | spin_unlock(&inode_lock); |
1182 | } |
1183 | EXPORT_SYMBOL(remove_inode_hash); |
1184 | |
1185 | /* |
1186 | * Tell the filesystem that this inode is no longer of any interest and should |
1187 | * be completely destroyed. |
1188 | * |
1189 | * We leave the inode in the inode hash table until *after* the filesystem's |
1190 | * ->delete_inode completes. This ensures that an iget (such as nfsd might |
1191 | * instigate) will always find up-to-date information either in the hash or on |
1192 | * disk. |
1193 | * |
1194 | * I_FREEING is set so that no-one will take a new reference to the inode while |
1195 | * it is being deleted. |
1196 | */ |
1197 | void generic_delete_inode(struct inode *inode) |
1198 | { |
1199 | const struct super_operations *op = inode->i_sb->s_op; |
1200 | |
1201 | list_del_init(&inode->i_list); |
1202 | list_del_init(&inode->i_sb_list); |
1203 | WARN_ON(inode->i_state & I_NEW); |
1204 | inode->i_state |= I_FREEING; |
1205 | inodes_stat.nr_inodes--; |
1206 | spin_unlock(&inode_lock); |
1207 | |
1208 | security_inode_delete(inode); |
1209 | |
1210 | if (op->delete_inode) { |
1211 | void (*delete)(struct inode *) = op->delete_inode; |
1212 | /* Filesystems implementing their own |
1213 | * s_op->delete_inode are required to call |
1214 | * truncate_inode_pages and clear_inode() |
1215 | * internally */ |
1216 | delete(inode); |
1217 | } else { |
1218 | truncate_inode_pages(&inode->i_data, 0); |
1219 | clear_inode(inode); |
1220 | } |
1221 | spin_lock(&inode_lock); |
1222 | hlist_del_init(&inode->i_hash); |
1223 | spin_unlock(&inode_lock); |
1224 | wake_up_inode(inode); |
1225 | BUG_ON(inode->i_state != I_CLEAR); |
1226 | destroy_inode(inode); |
1227 | } |
1228 | EXPORT_SYMBOL(generic_delete_inode); |
1229 | |
1230 | /** |
1231 | * generic_detach_inode - remove inode from inode lists |
1232 | * @inode: inode to remove |
1233 | * |
1234 | * Remove inode from inode lists, write it if it's dirty. This is just an |
1235 | * internal VFS helper exported for hugetlbfs. Do not use! |
1236 | * |
1237 | * Returns 1 if inode should be completely destroyed. |
1238 | */ |
1239 | int generic_detach_inode(struct inode *inode) |
1240 | { |
1241 | struct super_block *sb = inode->i_sb; |
1242 | |
1243 | if (!hlist_unhashed(&inode->i_hash)) { |
1244 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1245 | list_move(&inode->i_list, &inode_unused); |
1246 | inodes_stat.nr_unused++; |
1247 | if (sb->s_flags & MS_ACTIVE) { |
1248 | spin_unlock(&inode_lock); |
1249 | return 0; |
1250 | } |
1251 | WARN_ON(inode->i_state & I_NEW); |
1252 | inode->i_state |= I_WILL_FREE; |
1253 | spin_unlock(&inode_lock); |
1254 | write_inode_now(inode, 1); |
1255 | spin_lock(&inode_lock); |
1256 | WARN_ON(inode->i_state & I_NEW); |
1257 | inode->i_state &= ~I_WILL_FREE; |
1258 | inodes_stat.nr_unused--; |
1259 | hlist_del_init(&inode->i_hash); |
1260 | } |
1261 | list_del_init(&inode->i_list); |
1262 | list_del_init(&inode->i_sb_list); |
1263 | WARN_ON(inode->i_state & I_NEW); |
1264 | inode->i_state |= I_FREEING; |
1265 | inodes_stat.nr_inodes--; |
1266 | spin_unlock(&inode_lock); |
1267 | return 1; |
1268 | } |
1269 | EXPORT_SYMBOL_GPL(generic_detach_inode); |
1270 | |
1271 | static void generic_forget_inode(struct inode *inode) |
1272 | { |
1273 | if (!generic_detach_inode(inode)) |
1274 | return; |
1275 | if (inode->i_data.nrpages) |
1276 | truncate_inode_pages(&inode->i_data, 0); |
1277 | clear_inode(inode); |
1278 | wake_up_inode(inode); |
1279 | destroy_inode(inode); |
1280 | } |
1281 | |
1282 | /* |
1283 | * Normal UNIX filesystem behaviour: delete the |
1284 | * inode when the usage count drops to zero, and |
1285 | * i_nlink is zero. |
1286 | */ |
1287 | void generic_drop_inode(struct inode *inode) |
1288 | { |
1289 | if (!inode->i_nlink) |
1290 | generic_delete_inode(inode); |
1291 | else |
1292 | generic_forget_inode(inode); |
1293 | } |
1294 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1295 | |
1296 | /* |
1297 | * Called when we're dropping the last reference |
1298 | * to an inode. |
1299 | * |
1300 | * Call the FS "drop()" function, defaulting to |
1301 | * the legacy UNIX filesystem behaviour.. |
1302 | * |
1303 | * NOTE! NOTE! NOTE! We're called with the inode lock |
1304 | * held, and the drop function is supposed to release |
1305 | * the lock! |
1306 | */ |
1307 | static inline void iput_final(struct inode *inode) |
1308 | { |
1309 | const struct super_operations *op = inode->i_sb->s_op; |
1310 | void (*drop)(struct inode *) = generic_drop_inode; |
1311 | |
1312 | if (op && op->drop_inode) |
1313 | drop = op->drop_inode; |
1314 | drop(inode); |
1315 | } |
1316 | |
1317 | /** |
1318 | * iput - put an inode |
1319 | * @inode: inode to put |
1320 | * |
1321 | * Puts an inode, dropping its usage count. If the inode use count hits |
1322 | * zero, the inode is then freed and may also be destroyed. |
1323 | * |
1324 | * Consequently, iput() can sleep. |
1325 | */ |
1326 | void iput(struct inode *inode) |
1327 | { |
1328 | if (inode) { |
1329 | BUG_ON(inode->i_state == I_CLEAR); |
1330 | |
1331 | if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) |
1332 | iput_final(inode); |
1333 | } |
1334 | } |
1335 | EXPORT_SYMBOL(iput); |
1336 | |
1337 | /** |
1338 | * bmap - find a block number in a file |
1339 | * @inode: inode of file |
1340 | * @block: block to find |
1341 | * |
1342 | * Returns the block number on the device holding the inode that |
1343 | * is the disk block number for the block of the file requested. |
1344 | * That is, asked for block 4 of inode 1 the function will return the |
1345 | * disk block relative to the disk start that holds that block of the |
1346 | * file. |
1347 | */ |
1348 | sector_t bmap(struct inode *inode, sector_t block) |
1349 | { |
1350 | sector_t res = 0; |
1351 | if (inode->i_mapping->a_ops->bmap) |
1352 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
1353 | return res; |
1354 | } |
1355 | EXPORT_SYMBOL(bmap); |
1356 | |
1357 | /* |
1358 | * With relative atime, only update atime if the previous atime is |
1359 | * earlier than either the ctime or mtime or if at least a day has |
1360 | * passed since the last atime update. |
1361 | */ |
1362 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1363 | struct timespec now) |
1364 | { |
1365 | |
1366 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1367 | return 1; |
1368 | /* |
1369 | * Is mtime younger than atime? If yes, update atime: |
1370 | */ |
1371 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
1372 | return 1; |
1373 | /* |
1374 | * Is ctime younger than atime? If yes, update atime: |
1375 | */ |
1376 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
1377 | return 1; |
1378 | |
1379 | /* |
1380 | * Is the previous atime value older than a day? If yes, |
1381 | * update atime: |
1382 | */ |
1383 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
1384 | return 1; |
1385 | /* |
1386 | * Good, we can skip the atime update: |
1387 | */ |
1388 | return 0; |
1389 | } |
1390 | |
1391 | /** |
1392 | * touch_atime - update the access time |
1393 | * @mnt: mount the inode is accessed on |
1394 | * @dentry: dentry accessed |
1395 | * |
1396 | * Update the accessed time on an inode and mark it for writeback. |
1397 | * This function automatically handles read only file systems and media, |
1398 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1399 | */ |
1400 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1401 | { |
1402 | struct inode *inode = dentry->d_inode; |
1403 | struct timespec now; |
1404 | |
1405 | if (inode->i_flags & S_NOATIME) |
1406 | return; |
1407 | if (IS_NOATIME(inode)) |
1408 | return; |
1409 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1410 | return; |
1411 | |
1412 | if (mnt->mnt_flags & MNT_NOATIME) |
1413 | return; |
1414 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1415 | return; |
1416 | |
1417 | now = current_fs_time(inode->i_sb); |
1418 | |
1419 | if (!relatime_need_update(mnt, inode, now)) |
1420 | return; |
1421 | |
1422 | if (timespec_equal(&inode->i_atime, &now)) |
1423 | return; |
1424 | |
1425 | if (mnt_want_write(mnt)) |
1426 | return; |
1427 | |
1428 | inode->i_atime = now; |
1429 | mark_inode_dirty_sync(inode); |
1430 | mnt_drop_write(mnt); |
1431 | } |
1432 | EXPORT_SYMBOL(touch_atime); |
1433 | |
1434 | /** |
1435 | * file_update_time - update mtime and ctime time |
1436 | * @file: file accessed |
1437 | * |
1438 | * Update the mtime and ctime members of an inode and mark the inode |
1439 | * for writeback. Note that this function is meant exclusively for |
1440 | * usage in the file write path of filesystems, and filesystems may |
1441 | * choose to explicitly ignore update via this function with the |
1442 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
1443 | * timestamps are handled by the server. |
1444 | */ |
1445 | |
1446 | void file_update_time(struct file *file) |
1447 | { |
1448 | struct inode *inode = file->f_path.dentry->d_inode; |
1449 | struct timespec now; |
1450 | enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0; |
1451 | |
1452 | /* First try to exhaust all avenues to not sync */ |
1453 | if (IS_NOCMTIME(inode)) |
1454 | return; |
1455 | |
1456 | now = current_fs_time(inode->i_sb); |
1457 | if (!timespec_equal(&inode->i_mtime, &now)) |
1458 | sync_it = S_MTIME; |
1459 | |
1460 | if (!timespec_equal(&inode->i_ctime, &now)) |
1461 | sync_it |= S_CTIME; |
1462 | |
1463 | if (IS_I_VERSION(inode)) |
1464 | sync_it |= S_VERSION; |
1465 | |
1466 | if (!sync_it) |
1467 | return; |
1468 | |
1469 | /* Finally allowed to write? Takes lock. */ |
1470 | if (mnt_want_write_file(file)) |
1471 | return; |
1472 | |
1473 | /* Only change inode inside the lock region */ |
1474 | if (sync_it & S_VERSION) |
1475 | inode_inc_iversion(inode); |
1476 | if (sync_it & S_CTIME) |
1477 | inode->i_ctime = now; |
1478 | if (sync_it & S_MTIME) |
1479 | inode->i_mtime = now; |
1480 | mark_inode_dirty_sync(inode); |
1481 | mnt_drop_write(file->f_path.mnt); |
1482 | } |
1483 | EXPORT_SYMBOL(file_update_time); |
1484 | |
1485 | int inode_needs_sync(struct inode *inode) |
1486 | { |
1487 | if (IS_SYNC(inode)) |
1488 | return 1; |
1489 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
1490 | return 1; |
1491 | return 0; |
1492 | } |
1493 | EXPORT_SYMBOL(inode_needs_sync); |
1494 | |
1495 | int inode_wait(void *word) |
1496 | { |
1497 | schedule(); |
1498 | return 0; |
1499 | } |
1500 | EXPORT_SYMBOL(inode_wait); |
1501 | |
1502 | /* |
1503 | * If we try to find an inode in the inode hash while it is being |
1504 | * deleted, we have to wait until the filesystem completes its |
1505 | * deletion before reporting that it isn't found. This function waits |
1506 | * until the deletion _might_ have completed. Callers are responsible |
1507 | * to recheck inode state. |
1508 | * |
1509 | * It doesn't matter if I_NEW is not set initially, a call to |
1510 | * wake_up_inode() after removing from the hash list will DTRT. |
1511 | * |
1512 | * This is called with inode_lock held. |
1513 | */ |
1514 | static void __wait_on_freeing_inode(struct inode *inode) |
1515 | { |
1516 | wait_queue_head_t *wq; |
1517 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
1518 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
1519 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
1520 | spin_unlock(&inode_lock); |
1521 | schedule(); |
1522 | finish_wait(wq, &wait.wait); |
1523 | spin_lock(&inode_lock); |
1524 | } |
1525 | |
1526 | static __initdata unsigned long ihash_entries; |
1527 | static int __init set_ihash_entries(char *str) |
1528 | { |
1529 | if (!str) |
1530 | return 0; |
1531 | ihash_entries = simple_strtoul(str, &str, 0); |
1532 | return 1; |
1533 | } |
1534 | __setup("ihash_entries=", set_ihash_entries); |
1535 | |
1536 | /* |
1537 | * Initialize the waitqueues and inode hash table. |
1538 | */ |
1539 | void __init inode_init_early(void) |
1540 | { |
1541 | int loop; |
1542 | |
1543 | /* If hashes are distributed across NUMA nodes, defer |
1544 | * hash allocation until vmalloc space is available. |
1545 | */ |
1546 | if (hashdist) |
1547 | return; |
1548 | |
1549 | inode_hashtable = |
1550 | alloc_large_system_hash("Inode-cache", |
1551 | sizeof(struct hlist_head), |
1552 | ihash_entries, |
1553 | 14, |
1554 | HASH_EARLY, |
1555 | &i_hash_shift, |
1556 | &i_hash_mask, |
1557 | 0); |
1558 | |
1559 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1560 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1561 | } |
1562 | |
1563 | void __init inode_init(void) |
1564 | { |
1565 | int loop; |
1566 | |
1567 | /* inode slab cache */ |
1568 | inode_cachep = kmem_cache_create("inode_cache", |
1569 | sizeof(struct inode), |
1570 | 0, |
1571 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
1572 | SLAB_MEM_SPREAD), |
1573 | init_once); |
1574 | register_shrinker(&icache_shrinker); |
1575 | |
1576 | /* Hash may have been set up in inode_init_early */ |
1577 | if (!hashdist) |
1578 | return; |
1579 | |
1580 | inode_hashtable = |
1581 | alloc_large_system_hash("Inode-cache", |
1582 | sizeof(struct hlist_head), |
1583 | ihash_entries, |
1584 | 14, |
1585 | 0, |
1586 | &i_hash_shift, |
1587 | &i_hash_mask, |
1588 | 0); |
1589 | |
1590 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1591 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1592 | } |
1593 | |
1594 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
1595 | { |
1596 | inode->i_mode = mode; |
1597 | if (S_ISCHR(mode)) { |
1598 | inode->i_fop = &def_chr_fops; |
1599 | inode->i_rdev = rdev; |
1600 | } else if (S_ISBLK(mode)) { |
1601 | inode->i_fop = &def_blk_fops; |
1602 | inode->i_rdev = rdev; |
1603 | } else if (S_ISFIFO(mode)) |
1604 | inode->i_fop = &def_fifo_fops; |
1605 | else if (S_ISSOCK(mode)) |
1606 | inode->i_fop = &bad_sock_fops; |
1607 | else |
1608 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
1609 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
1610 | inode->i_ino); |
1611 | } |
1612 | EXPORT_SYMBOL(init_special_inode); |
1613 |
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