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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/quotaops.h> |
12 | #include <linux/slab.h> |
13 | #include <linux/writeback.h> |
14 | #include <linux/module.h> |
15 | #include <linux/backing-dev.h> |
16 | #include <linux/wait.h> |
17 | #include <linux/rwsem.h> |
18 | #include <linux/hash.h> |
19 | #include <linux/swap.h> |
20 | #include <linux/security.h> |
21 | #include <linux/ima.h> |
22 | #include <linux/pagemap.h> |
23 | #include <linux/cdev.h> |
24 | #include <linux/bootmem.h> |
25 | #include <linux/inotify.h> |
26 | #include <linux/fsnotify.h> |
27 | #include <linux/mount.h> |
28 | #include <linux/async.h> |
29 | #include <linux/posix_acl.h> |
30 | |
31 | /* |
32 | * This is needed for the following functions: |
33 | * - inode_has_buffers |
34 | * - invalidate_inode_buffers |
35 | * - invalidate_bdev |
36 | * |
37 | * FIXME: remove all knowledge of the buffer layer from this file |
38 | */ |
39 | #include <linux/buffer_head.h> |
40 | |
41 | /* |
42 | * New inode.c implementation. |
43 | * |
44 | * This implementation has the basic premise of trying |
45 | * to be extremely low-overhead and SMP-safe, yet be |
46 | * simple enough to be "obviously correct". |
47 | * |
48 | * Famous last words. |
49 | */ |
50 | |
51 | /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */ |
52 | |
53 | /* #define INODE_PARANOIA 1 */ |
54 | /* #define INODE_DEBUG 1 */ |
55 | |
56 | /* |
57 | * Inode lookup is no longer as critical as it used to be: |
58 | * most of the lookups are going to be through the dcache. |
59 | */ |
60 | #define I_HASHBITS i_hash_shift |
61 | #define I_HASHMASK i_hash_mask |
62 | |
63 | static unsigned int i_hash_mask __read_mostly; |
64 | static unsigned int i_hash_shift __read_mostly; |
65 | |
66 | /* |
67 | * Each inode can be on two separate lists. One is |
68 | * the hash list of the inode, used for lookups. The |
69 | * other linked list is the "type" list: |
70 | * "in_use" - valid inode, i_count > 0, i_nlink > 0 |
71 | * "dirty" - as "in_use" but also dirty |
72 | * "unused" - valid inode, i_count = 0 |
73 | * |
74 | * A "dirty" list is maintained for each super block, |
75 | * allowing for low-overhead inode sync() operations. |
76 | */ |
77 | |
78 | LIST_HEAD(inode_in_use); |
79 | LIST_HEAD(inode_unused); |
80 | static struct hlist_head *inode_hashtable __read_mostly; |
81 | |
82 | /* |
83 | * A simple spinlock to protect the list manipulations. |
84 | * |
85 | * NOTE! You also have to own the lock if you change |
86 | * the i_state of an inode while it is in use.. |
87 | */ |
88 | DEFINE_SPINLOCK(inode_lock); |
89 | |
90 | /* |
91 | * iprune_sem provides exclusion between the kswapd or try_to_free_pages |
92 | * icache shrinking path, and the umount path. Without this exclusion, |
93 | * by the time prune_icache calls iput for the inode whose pages it has |
94 | * been invalidating, or by the time it calls clear_inode & destroy_inode |
95 | * from its final dispose_list, the struct super_block they refer to |
96 | * (for inode->i_sb->s_op) may already have been freed and reused. |
97 | * |
98 | * We make this an rwsem because the fastpath is icache shrinking. In |
99 | * some cases a filesystem may be doing a significant amount of work in |
100 | * its inode reclaim code, so this should improve parallelism. |
101 | */ |
102 | static DECLARE_RWSEM(iprune_sem); |
103 | |
104 | /* |
105 | * Statistics gathering.. |
106 | */ |
107 | struct inodes_stat_t inodes_stat; |
108 | |
109 | static struct kmem_cache *inode_cachep __read_mostly; |
110 | |
111 | static void wake_up_inode(struct inode *inode) |
112 | { |
113 | /* |
114 | * Prevent speculative execution through spin_unlock(&inode_lock); |
115 | */ |
116 | smp_mb(); |
117 | wake_up_bit(&inode->i_state, __I_LOCK); |
118 | } |
119 | |
120 | /** |
121 | * inode_init_always - perform inode structure intialisation |
122 | * @sb: superblock inode belongs to |
123 | * @inode: inode to initialise |
124 | * |
125 | * These are initializations that need to be done on every inode |
126 | * allocation as the fields are not initialised by slab allocation. |
127 | */ |
128 | int inode_init_always(struct super_block *sb, struct inode *inode) |
129 | { |
130 | static const struct address_space_operations empty_aops; |
131 | static const struct inode_operations empty_iops; |
132 | static const struct file_operations empty_fops; |
133 | struct address_space *const mapping = &inode->i_data; |
134 | |
135 | inode->i_sb = sb; |
136 | inode->i_blkbits = sb->s_blocksize_bits; |
137 | inode->i_flags = 0; |
138 | atomic_set(&inode->i_count, 1); |
139 | inode->i_op = &empty_iops; |
140 | inode->i_fop = &empty_fops; |
141 | inode->i_nlink = 1; |
142 | inode->i_uid = 0; |
143 | inode->i_gid = 0; |
144 | atomic_set(&inode->i_writecount, 0); |
145 | inode->i_size = 0; |
146 | inode->i_blocks = 0; |
147 | inode->i_bytes = 0; |
148 | inode->i_generation = 0; |
149 | #ifdef CONFIG_QUOTA |
150 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
151 | #endif |
152 | inode->i_pipe = NULL; |
153 | inode->i_bdev = NULL; |
154 | inode->i_cdev = NULL; |
155 | inode->i_rdev = 0; |
156 | inode->dirtied_when = 0; |
157 | |
158 | if (security_inode_alloc(inode)) |
159 | goto out; |
160 | |
161 | /* allocate and initialize an i_integrity */ |
162 | if (ima_inode_alloc(inode)) |
163 | goto out_free_security; |
164 | |
165 | spin_lock_init(&inode->i_lock); |
166 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
167 | |
168 | mutex_init(&inode->i_mutex); |
169 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
170 | |
171 | init_rwsem(&inode->i_alloc_sem); |
172 | lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); |
173 | |
174 | mapping->a_ops = &empty_aops; |
175 | mapping->host = inode; |
176 | mapping->flags = 0; |
177 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
178 | mapping->assoc_mapping = NULL; |
179 | mapping->backing_dev_info = &default_backing_dev_info; |
180 | mapping->writeback_index = 0; |
181 | |
182 | /* |
183 | * If the block_device provides a backing_dev_info for client |
184 | * inodes then use that. Otherwise the inode share the bdev's |
185 | * backing_dev_info. |
186 | */ |
187 | if (sb->s_bdev) { |
188 | struct backing_dev_info *bdi; |
189 | |
190 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
191 | mapping->backing_dev_info = bdi; |
192 | } |
193 | inode->i_private = NULL; |
194 | inode->i_mapping = mapping; |
195 | #ifdef CONFIG_FS_POSIX_ACL |
196 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
197 | #endif |
198 | |
199 | #ifdef CONFIG_FSNOTIFY |
200 | inode->i_fsnotify_mask = 0; |
201 | #endif |
202 | |
203 | return 0; |
204 | |
205 | out_free_security: |
206 | security_inode_free(inode); |
207 | out: |
208 | return -ENOMEM; |
209 | } |
210 | EXPORT_SYMBOL(inode_init_always); |
211 | |
212 | static struct inode *alloc_inode(struct super_block *sb) |
213 | { |
214 | struct inode *inode; |
215 | |
216 | if (sb->s_op->alloc_inode) |
217 | inode = sb->s_op->alloc_inode(sb); |
218 | else |
219 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
220 | |
221 | if (!inode) |
222 | return NULL; |
223 | |
224 | if (unlikely(inode_init_always(sb, inode))) { |
225 | if (inode->i_sb->s_op->destroy_inode) |
226 | inode->i_sb->s_op->destroy_inode(inode); |
227 | else |
228 | kmem_cache_free(inode_cachep, inode); |
229 | return NULL; |
230 | } |
231 | |
232 | return inode; |
233 | } |
234 | |
235 | void __destroy_inode(struct inode *inode) |
236 | { |
237 | BUG_ON(inode_has_buffers(inode)); |
238 | ima_inode_free(inode); |
239 | security_inode_free(inode); |
240 | fsnotify_inode_delete(inode); |
241 | #ifdef CONFIG_FS_POSIX_ACL |
242 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
243 | posix_acl_release(inode->i_acl); |
244 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
245 | posix_acl_release(inode->i_default_acl); |
246 | #endif |
247 | } |
248 | EXPORT_SYMBOL(__destroy_inode); |
249 | |
250 | void destroy_inode(struct inode *inode) |
251 | { |
252 | __destroy_inode(inode); |
253 | if (inode->i_sb->s_op->destroy_inode) |
254 | inode->i_sb->s_op->destroy_inode(inode); |
255 | else |
256 | kmem_cache_free(inode_cachep, (inode)); |
257 | } |
258 | |
259 | /* |
260 | * These are initializations that only need to be done |
261 | * once, because the fields are idempotent across use |
262 | * of the inode, so let the slab aware of that. |
263 | */ |
264 | void inode_init_once(struct inode *inode) |
265 | { |
266 | memset(inode, 0, sizeof(*inode)); |
267 | INIT_HLIST_NODE(&inode->i_hash); |
268 | INIT_LIST_HEAD(&inode->i_dentry); |
269 | INIT_LIST_HEAD(&inode->i_devices); |
270 | INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); |
271 | spin_lock_init(&inode->i_data.tree_lock); |
272 | spin_lock_init(&inode->i_data.i_mmap_lock); |
273 | INIT_LIST_HEAD(&inode->i_data.private_list); |
274 | spin_lock_init(&inode->i_data.private_lock); |
275 | INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap); |
276 | INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear); |
277 | i_size_ordered_init(inode); |
278 | #ifdef CONFIG_INOTIFY |
279 | INIT_LIST_HEAD(&inode->inotify_watches); |
280 | mutex_init(&inode->inotify_mutex); |
281 | #endif |
282 | #ifdef CONFIG_FSNOTIFY |
283 | INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries); |
284 | #endif |
285 | } |
286 | EXPORT_SYMBOL(inode_init_once); |
287 | |
288 | static void init_once(void *foo) |
289 | { |
290 | struct inode *inode = (struct inode *) foo; |
291 | |
292 | inode_init_once(inode); |
293 | } |
294 | |
295 | /* |
296 | * inode_lock must be held |
297 | */ |
298 | void __iget(struct inode *inode) |
299 | { |
300 | if (atomic_read(&inode->i_count)) { |
301 | atomic_inc(&inode->i_count); |
302 | return; |
303 | } |
304 | atomic_inc(&inode->i_count); |
305 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
306 | list_move(&inode->i_list, &inode_in_use); |
307 | inodes_stat.nr_unused--; |
308 | } |
309 | |
310 | /** |
311 | * clear_inode - clear an inode |
312 | * @inode: inode to clear |
313 | * |
314 | * This is called by the filesystem to tell us |
315 | * that the inode is no longer useful. We just |
316 | * terminate it with extreme prejudice. |
317 | */ |
318 | void clear_inode(struct inode *inode) |
319 | { |
320 | might_sleep(); |
321 | invalidate_inode_buffers(inode); |
322 | |
323 | BUG_ON(inode->i_data.nrpages); |
324 | BUG_ON(!(inode->i_state & I_FREEING)); |
325 | BUG_ON(inode->i_state & I_CLEAR); |
326 | inode_sync_wait(inode); |
327 | vfs_dq_drop(inode); |
328 | if (inode->i_sb->s_op->clear_inode) |
329 | inode->i_sb->s_op->clear_inode(inode); |
330 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
331 | bd_forget(inode); |
332 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
333 | cd_forget(inode); |
334 | inode->i_state = I_CLEAR; |
335 | } |
336 | EXPORT_SYMBOL(clear_inode); |
337 | |
338 | /* |
339 | * dispose_list - dispose of the contents of a local list |
340 | * @head: the head of the list to free |
341 | * |
342 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
343 | * need to worry about list corruption and SMP locks. |
344 | */ |
345 | static void dispose_list(struct list_head *head) |
346 | { |
347 | int nr_disposed = 0; |
348 | |
349 | while (!list_empty(head)) { |
350 | struct inode *inode; |
351 | |
352 | inode = list_first_entry(head, struct inode, i_list); |
353 | list_del(&inode->i_list); |
354 | |
355 | if (inode->i_data.nrpages) |
356 | truncate_inode_pages(&inode->i_data, 0); |
357 | clear_inode(inode); |
358 | |
359 | spin_lock(&inode_lock); |
360 | hlist_del_init(&inode->i_hash); |
361 | list_del_init(&inode->i_sb_list); |
362 | spin_unlock(&inode_lock); |
363 | |
364 | wake_up_inode(inode); |
365 | destroy_inode(inode); |
366 | nr_disposed++; |
367 | } |
368 | spin_lock(&inode_lock); |
369 | inodes_stat.nr_inodes -= nr_disposed; |
370 | spin_unlock(&inode_lock); |
371 | } |
372 | |
373 | /* |
374 | * Invalidate all inodes for a device. |
375 | */ |
376 | static int invalidate_list(struct list_head *head, struct list_head *dispose) |
377 | { |
378 | struct list_head *next; |
379 | int busy = 0, count = 0; |
380 | |
381 | next = head->next; |
382 | for (;;) { |
383 | struct list_head *tmp = next; |
384 | struct inode *inode; |
385 | |
386 | /* |
387 | * We can reschedule here without worrying about the list's |
388 | * consistency because the per-sb list of inodes must not |
389 | * change during umount anymore, and because iprune_sem keeps |
390 | * shrink_icache_memory() away. |
391 | */ |
392 | cond_resched_lock(&inode_lock); |
393 | |
394 | next = next->next; |
395 | if (tmp == head) |
396 | break; |
397 | inode = list_entry(tmp, struct inode, i_sb_list); |
398 | if (inode->i_state & I_NEW) |
399 | continue; |
400 | invalidate_inode_buffers(inode); |
401 | if (!atomic_read(&inode->i_count)) { |
402 | list_move(&inode->i_list, dispose); |
403 | WARN_ON(inode->i_state & I_NEW); |
404 | inode->i_state |= I_FREEING; |
405 | count++; |
406 | continue; |
407 | } |
408 | busy = 1; |
409 | } |
410 | /* only unused inodes may be cached with i_count zero */ |
411 | inodes_stat.nr_unused -= count; |
412 | return busy; |
413 | } |
414 | |
415 | /** |
416 | * invalidate_inodes - discard the inodes on a device |
417 | * @sb: superblock |
418 | * |
419 | * Discard all of the inodes for a given superblock. If the discard |
420 | * fails because there are busy inodes then a non zero value is returned. |
421 | * If the discard is successful all the inodes have been discarded. |
422 | */ |
423 | int invalidate_inodes(struct super_block *sb) |
424 | { |
425 | int busy; |
426 | LIST_HEAD(throw_away); |
427 | |
428 | down_write(&iprune_sem); |
429 | spin_lock(&inode_lock); |
430 | inotify_unmount_inodes(&sb->s_inodes); |
431 | fsnotify_unmount_inodes(&sb->s_inodes); |
432 | busy = invalidate_list(&sb->s_inodes, &throw_away); |
433 | spin_unlock(&inode_lock); |
434 | |
435 | dispose_list(&throw_away); |
436 | up_write(&iprune_sem); |
437 | |
438 | return busy; |
439 | } |
440 | EXPORT_SYMBOL(invalidate_inodes); |
441 | |
442 | static int can_unuse(struct inode *inode) |
443 | { |
444 | if (inode->i_state) |
445 | return 0; |
446 | if (inode_has_buffers(inode)) |
447 | return 0; |
448 | if (atomic_read(&inode->i_count)) |
449 | return 0; |
450 | if (inode->i_data.nrpages) |
451 | return 0; |
452 | return 1; |
453 | } |
454 | |
455 | /* |
456 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to |
457 | * a temporary list and then are freed outside inode_lock by dispose_list(). |
458 | * |
459 | * Any inodes which are pinned purely because of attached pagecache have their |
460 | * pagecache removed. We expect the final iput() on that inode to add it to |
461 | * the front of the inode_unused list. So look for it there and if the |
462 | * inode is still freeable, proceed. The right inode is found 99.9% of the |
463 | * time in testing on a 4-way. |
464 | * |
465 | * If the inode has metadata buffers attached to mapping->private_list then |
466 | * try to remove them. |
467 | */ |
468 | static void prune_icache(int nr_to_scan) |
469 | { |
470 | LIST_HEAD(freeable); |
471 | int nr_pruned = 0; |
472 | int nr_scanned; |
473 | unsigned long reap = 0; |
474 | |
475 | down_read(&iprune_sem); |
476 | spin_lock(&inode_lock); |
477 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { |
478 | struct inode *inode; |
479 | |
480 | if (list_empty(&inode_unused)) |
481 | break; |
482 | |
483 | inode = list_entry(inode_unused.prev, struct inode, i_list); |
484 | |
485 | if (inode->i_state || atomic_read(&inode->i_count)) { |
486 | list_move(&inode->i_list, &inode_unused); |
487 | continue; |
488 | } |
489 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
490 | __iget(inode); |
491 | spin_unlock(&inode_lock); |
492 | if (remove_inode_buffers(inode)) |
493 | reap += invalidate_mapping_pages(&inode->i_data, |
494 | 0, -1); |
495 | iput(inode); |
496 | spin_lock(&inode_lock); |
497 | |
498 | if (inode != list_entry(inode_unused.next, |
499 | struct inode, i_list)) |
500 | continue; /* wrong inode or list_empty */ |
501 | if (!can_unuse(inode)) |
502 | continue; |
503 | } |
504 | list_move(&inode->i_list, &freeable); |
505 | WARN_ON(inode->i_state & I_NEW); |
506 | inode->i_state |= I_FREEING; |
507 | nr_pruned++; |
508 | } |
509 | inodes_stat.nr_unused -= nr_pruned; |
510 | if (current_is_kswapd()) |
511 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
512 | else |
513 | __count_vm_events(PGINODESTEAL, reap); |
514 | spin_unlock(&inode_lock); |
515 | |
516 | dispose_list(&freeable); |
517 | up_read(&iprune_sem); |
518 | } |
519 | |
520 | /* |
521 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, |
522 | * "unused" means that no dentries are referring to the inodes: the files are |
523 | * not open and the dcache references to those inodes have already been |
524 | * reclaimed. |
525 | * |
526 | * This function is passed the number of inodes to scan, and it returns the |
527 | * total number of remaining possibly-reclaimable inodes. |
528 | */ |
529 | static int shrink_icache_memory(int nr, gfp_t gfp_mask) |
530 | { |
531 | if (nr) { |
532 | /* |
533 | * Nasty deadlock avoidance. We may hold various FS locks, |
534 | * and we don't want to recurse into the FS that called us |
535 | * in clear_inode() and friends.. |
536 | */ |
537 | if (!(gfp_mask & __GFP_FS)) |
538 | return -1; |
539 | prune_icache(nr); |
540 | } |
541 | return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; |
542 | } |
543 | |
544 | static struct shrinker icache_shrinker = { |
545 | .shrink = shrink_icache_memory, |
546 | .seeks = DEFAULT_SEEKS, |
547 | }; |
548 | |
549 | static void __wait_on_freeing_inode(struct inode *inode); |
550 | /* |
551 | * Called with the inode lock held. |
552 | * NOTE: we are not increasing the inode-refcount, you must call __iget() |
553 | * by hand after calling find_inode now! This simplifies iunique and won't |
554 | * add any additional branch in the common code. |
555 | */ |
556 | static struct inode *find_inode(struct super_block *sb, |
557 | struct hlist_head *head, |
558 | int (*test)(struct inode *, void *), |
559 | void *data) |
560 | { |
561 | struct hlist_node *node; |
562 | struct inode *inode = NULL; |
563 | |
564 | repeat: |
565 | hlist_for_each_entry(inode, node, head, i_hash) { |
566 | if (inode->i_sb != sb) |
567 | continue; |
568 | if (!test(inode, data)) |
569 | continue; |
570 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
571 | __wait_on_freeing_inode(inode); |
572 | goto repeat; |
573 | } |
574 | break; |
575 | } |
576 | return node ? inode : NULL; |
577 | } |
578 | |
579 | /* |
580 | * find_inode_fast is the fast path version of find_inode, see the comment at |
581 | * iget_locked for details. |
582 | */ |
583 | static struct inode *find_inode_fast(struct super_block *sb, |
584 | struct hlist_head *head, unsigned long ino) |
585 | { |
586 | struct hlist_node *node; |
587 | struct inode *inode = NULL; |
588 | |
589 | repeat: |
590 | hlist_for_each_entry(inode, node, head, i_hash) { |
591 | if (inode->i_ino != ino) |
592 | continue; |
593 | if (inode->i_sb != sb) |
594 | continue; |
595 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
596 | __wait_on_freeing_inode(inode); |
597 | goto repeat; |
598 | } |
599 | break; |
600 | } |
601 | return node ? inode : NULL; |
602 | } |
603 | |
604 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
605 | { |
606 | unsigned long tmp; |
607 | |
608 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
609 | L1_CACHE_BYTES; |
610 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); |
611 | return tmp & I_HASHMASK; |
612 | } |
613 | |
614 | static inline void |
615 | __inode_add_to_lists(struct super_block *sb, struct hlist_head *head, |
616 | struct inode *inode) |
617 | { |
618 | inodes_stat.nr_inodes++; |
619 | list_add(&inode->i_list, &inode_in_use); |
620 | list_add(&inode->i_sb_list, &sb->s_inodes); |
621 | if (head) |
622 | hlist_add_head(&inode->i_hash, head); |
623 | } |
624 | |
625 | /** |
626 | * inode_add_to_lists - add a new inode to relevant lists |
627 | * @sb: superblock inode belongs to |
628 | * @inode: inode to mark in use |
629 | * |
630 | * When an inode is allocated it needs to be accounted for, added to the in use |
631 | * list, the owning superblock and the inode hash. This needs to be done under |
632 | * the inode_lock, so export a function to do this rather than the inode lock |
633 | * itself. We calculate the hash list to add to here so it is all internal |
634 | * which requires the caller to have already set up the inode number in the |
635 | * inode to add. |
636 | */ |
637 | void inode_add_to_lists(struct super_block *sb, struct inode *inode) |
638 | { |
639 | struct hlist_head *head = inode_hashtable + hash(sb, inode->i_ino); |
640 | |
641 | spin_lock(&inode_lock); |
642 | __inode_add_to_lists(sb, head, inode); |
643 | spin_unlock(&inode_lock); |
644 | } |
645 | EXPORT_SYMBOL_GPL(inode_add_to_lists); |
646 | |
647 | /** |
648 | * new_inode - obtain an inode |
649 | * @sb: superblock |
650 | * |
651 | * Allocates a new inode for given superblock. The default gfp_mask |
652 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
653 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
654 | * for the page cache are not reclaimable or migratable, |
655 | * mapping_set_gfp_mask() must be called with suitable flags on the |
656 | * newly created inode's mapping |
657 | * |
658 | */ |
659 | struct inode *new_inode(struct super_block *sb) |
660 | { |
661 | /* |
662 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
663 | * error if st_ino won't fit in target struct field. Use 32bit counter |
664 | * here to attempt to avoid that. |
665 | */ |
666 | static unsigned int last_ino; |
667 | struct inode *inode; |
668 | |
669 | spin_lock_prefetch(&inode_lock); |
670 | |
671 | inode = alloc_inode(sb); |
672 | if (inode) { |
673 | spin_lock(&inode_lock); |
674 | __inode_add_to_lists(sb, NULL, inode); |
675 | inode->i_ino = ++last_ino; |
676 | inode->i_state = 0; |
677 | spin_unlock(&inode_lock); |
678 | } |
679 | return inode; |
680 | } |
681 | EXPORT_SYMBOL(new_inode); |
682 | |
683 | void unlock_new_inode(struct inode *inode) |
684 | { |
685 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
686 | if (inode->i_mode & S_IFDIR) { |
687 | struct file_system_type *type = inode->i_sb->s_type; |
688 | |
689 | /* Set new key only if filesystem hasn't already changed it */ |
690 | if (!lockdep_match_class(&inode->i_mutex, |
691 | &type->i_mutex_key)) { |
692 | /* |
693 | * ensure nobody is actually holding i_mutex |
694 | */ |
695 | mutex_destroy(&inode->i_mutex); |
696 | mutex_init(&inode->i_mutex); |
697 | lockdep_set_class(&inode->i_mutex, |
698 | &type->i_mutex_dir_key); |
699 | } |
700 | } |
701 | #endif |
702 | /* |
703 | * This is special! We do not need the spinlock when clearing I_LOCK, |
704 | * because we're guaranteed that nobody else tries to do anything about |
705 | * the state of the inode when it is locked, as we just created it (so |
706 | * there can be no old holders that haven't tested I_LOCK). |
707 | * However we must emit the memory barrier so that other CPUs reliably |
708 | * see the clearing of I_LOCK after the other inode initialisation has |
709 | * completed. |
710 | */ |
711 | smp_mb(); |
712 | WARN_ON((inode->i_state & (I_LOCK|I_NEW)) != (I_LOCK|I_NEW)); |
713 | inode->i_state &= ~(I_LOCK|I_NEW); |
714 | wake_up_inode(inode); |
715 | } |
716 | EXPORT_SYMBOL(unlock_new_inode); |
717 | |
718 | /* |
719 | * This is called without the inode lock held.. Be careful. |
720 | * |
721 | * We no longer cache the sb_flags in i_flags - see fs.h |
722 | * -- rmk@arm.uk.linux.org |
723 | */ |
724 | static struct inode *get_new_inode(struct super_block *sb, |
725 | struct hlist_head *head, |
726 | int (*test)(struct inode *, void *), |
727 | int (*set)(struct inode *, void *), |
728 | void *data) |
729 | { |
730 | struct inode *inode; |
731 | |
732 | inode = alloc_inode(sb); |
733 | if (inode) { |
734 | struct inode *old; |
735 | |
736 | spin_lock(&inode_lock); |
737 | /* We released the lock, so.. */ |
738 | old = find_inode(sb, head, test, data); |
739 | if (!old) { |
740 | if (set(inode, data)) |
741 | goto set_failed; |
742 | |
743 | __inode_add_to_lists(sb, head, inode); |
744 | inode->i_state = I_LOCK|I_NEW; |
745 | spin_unlock(&inode_lock); |
746 | |
747 | /* Return the locked inode with I_NEW set, the |
748 | * caller is responsible for filling in the contents |
749 | */ |
750 | return inode; |
751 | } |
752 | |
753 | /* |
754 | * Uhhuh, somebody else created the same inode under |
755 | * us. Use the old inode instead of the one we just |
756 | * allocated. |
757 | */ |
758 | __iget(old); |
759 | spin_unlock(&inode_lock); |
760 | destroy_inode(inode); |
761 | inode = old; |
762 | wait_on_inode(inode); |
763 | } |
764 | return inode; |
765 | |
766 | set_failed: |
767 | spin_unlock(&inode_lock); |
768 | destroy_inode(inode); |
769 | return NULL; |
770 | } |
771 | |
772 | /* |
773 | * get_new_inode_fast is the fast path version of get_new_inode, see the |
774 | * comment at iget_locked for details. |
775 | */ |
776 | static struct inode *get_new_inode_fast(struct super_block *sb, |
777 | struct hlist_head *head, unsigned long ino) |
778 | { |
779 | struct inode *inode; |
780 | |
781 | inode = alloc_inode(sb); |
782 | if (inode) { |
783 | struct inode *old; |
784 | |
785 | spin_lock(&inode_lock); |
786 | /* We released the lock, so.. */ |
787 | old = find_inode_fast(sb, head, ino); |
788 | if (!old) { |
789 | inode->i_ino = ino; |
790 | __inode_add_to_lists(sb, head, inode); |
791 | inode->i_state = I_LOCK|I_NEW; |
792 | spin_unlock(&inode_lock); |
793 | |
794 | /* Return the locked inode with I_NEW set, the |
795 | * caller is responsible for filling in the contents |
796 | */ |
797 | return inode; |
798 | } |
799 | |
800 | /* |
801 | * Uhhuh, somebody else created the same inode under |
802 | * us. Use the old inode instead of the one we just |
803 | * allocated. |
804 | */ |
805 | __iget(old); |
806 | spin_unlock(&inode_lock); |
807 | destroy_inode(inode); |
808 | inode = old; |
809 | wait_on_inode(inode); |
810 | } |
811 | return inode; |
812 | } |
813 | |
814 | /** |
815 | * iunique - get a unique inode number |
816 | * @sb: superblock |
817 | * @max_reserved: highest reserved inode number |
818 | * |
819 | * Obtain an inode number that is unique on the system for a given |
820 | * superblock. This is used by file systems that have no natural |
821 | * permanent inode numbering system. An inode number is returned that |
822 | * is higher than the reserved limit but unique. |
823 | * |
824 | * BUGS: |
825 | * With a large number of inodes live on the file system this function |
826 | * currently becomes quite slow. |
827 | */ |
828 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
829 | { |
830 | /* |
831 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
832 | * error if st_ino won't fit in target struct field. Use 32bit counter |
833 | * here to attempt to avoid that. |
834 | */ |
835 | static unsigned int counter; |
836 | struct inode *inode; |
837 | struct hlist_head *head; |
838 | ino_t res; |
839 | |
840 | spin_lock(&inode_lock); |
841 | do { |
842 | if (counter <= max_reserved) |
843 | counter = max_reserved + 1; |
844 | res = counter++; |
845 | head = inode_hashtable + hash(sb, res); |
846 | inode = find_inode_fast(sb, head, res); |
847 | } while (inode != NULL); |
848 | spin_unlock(&inode_lock); |
849 | |
850 | return res; |
851 | } |
852 | EXPORT_SYMBOL(iunique); |
853 | |
854 | struct inode *igrab(struct inode *inode) |
855 | { |
856 | spin_lock(&inode_lock); |
857 | if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))) |
858 | __iget(inode); |
859 | else |
860 | /* |
861 | * Handle the case where s_op->clear_inode is not been |
862 | * called yet, and somebody is calling igrab |
863 | * while the inode is getting freed. |
864 | */ |
865 | inode = NULL; |
866 | spin_unlock(&inode_lock); |
867 | return inode; |
868 | } |
869 | EXPORT_SYMBOL(igrab); |
870 | |
871 | /** |
872 | * ifind - internal function, you want ilookup5() or iget5(). |
873 | * @sb: super block of file system to search |
874 | * @head: the head of the list to search |
875 | * @test: callback used for comparisons between inodes |
876 | * @data: opaque data pointer to pass to @test |
877 | * @wait: if true wait for the inode to be unlocked, if false do not |
878 | * |
879 | * ifind() searches for the inode specified by @data in the inode |
880 | * cache. This is a generalized version of ifind_fast() for file systems where |
881 | * the inode number is not sufficient for unique identification of an inode. |
882 | * |
883 | * If the inode is in the cache, the inode is returned with an incremented |
884 | * reference count. |
885 | * |
886 | * Otherwise NULL is returned. |
887 | * |
888 | * Note, @test is called with the inode_lock held, so can't sleep. |
889 | */ |
890 | static struct inode *ifind(struct super_block *sb, |
891 | struct hlist_head *head, int (*test)(struct inode *, void *), |
892 | void *data, const int wait) |
893 | { |
894 | struct inode *inode; |
895 | |
896 | spin_lock(&inode_lock); |
897 | inode = find_inode(sb, head, test, data); |
898 | if (inode) { |
899 | __iget(inode); |
900 | spin_unlock(&inode_lock); |
901 | if (likely(wait)) |
902 | wait_on_inode(inode); |
903 | return inode; |
904 | } |
905 | spin_unlock(&inode_lock); |
906 | return NULL; |
907 | } |
908 | |
909 | /** |
910 | * ifind_fast - internal function, you want ilookup() or iget(). |
911 | * @sb: super block of file system to search |
912 | * @head: head of the list to search |
913 | * @ino: inode number to search for |
914 | * |
915 | * ifind_fast() searches for the inode @ino in the inode cache. This is for |
916 | * file systems where the inode number is sufficient for unique identification |
917 | * of an inode. |
918 | * |
919 | * If the inode is in the cache, the inode is returned with an incremented |
920 | * reference count. |
921 | * |
922 | * Otherwise NULL is returned. |
923 | */ |
924 | static struct inode *ifind_fast(struct super_block *sb, |
925 | struct hlist_head *head, unsigned long ino) |
926 | { |
927 | struct inode *inode; |
928 | |
929 | spin_lock(&inode_lock); |
930 | inode = find_inode_fast(sb, head, ino); |
931 | if (inode) { |
932 | __iget(inode); |
933 | spin_unlock(&inode_lock); |
934 | wait_on_inode(inode); |
935 | return inode; |
936 | } |
937 | spin_unlock(&inode_lock); |
938 | return NULL; |
939 | } |
940 | |
941 | /** |
942 | * ilookup5_nowait - search for an inode in the inode cache |
943 | * @sb: super block of file system to search |
944 | * @hashval: hash value (usually inode number) to search for |
945 | * @test: callback used for comparisons between inodes |
946 | * @data: opaque data pointer to pass to @test |
947 | * |
948 | * ilookup5() uses ifind() to search for the inode specified by @hashval and |
949 | * @data in the inode cache. This is a generalized version of ilookup() for |
950 | * file systems where the inode number is not sufficient for unique |
951 | * identification of an inode. |
952 | * |
953 | * If the inode is in the cache, the inode is returned with an incremented |
954 | * reference count. Note, the inode lock is not waited upon so you have to be |
955 | * very careful what you do with the returned inode. You probably should be |
956 | * using ilookup5() instead. |
957 | * |
958 | * Otherwise NULL is returned. |
959 | * |
960 | * Note, @test is called with the inode_lock held, so can't sleep. |
961 | */ |
962 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
963 | int (*test)(struct inode *, void *), void *data) |
964 | { |
965 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
966 | |
967 | return ifind(sb, head, test, data, 0); |
968 | } |
969 | EXPORT_SYMBOL(ilookup5_nowait); |
970 | |
971 | /** |
972 | * ilookup5 - search for an inode in the inode cache |
973 | * @sb: super block of file system to search |
974 | * @hashval: hash value (usually inode number) to search for |
975 | * @test: callback used for comparisons between inodes |
976 | * @data: opaque data pointer to pass to @test |
977 | * |
978 | * ilookup5() uses ifind() to search for the inode specified by @hashval and |
979 | * @data in the inode cache. This is a generalized version of ilookup() for |
980 | * file systems where the inode number is not sufficient for unique |
981 | * identification of an inode. |
982 | * |
983 | * If the inode is in the cache, the inode lock is waited upon and the inode is |
984 | * returned with an incremented reference count. |
985 | * |
986 | * Otherwise NULL is returned. |
987 | * |
988 | * Note, @test is called with the inode_lock held, so can't sleep. |
989 | */ |
990 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
991 | int (*test)(struct inode *, void *), void *data) |
992 | { |
993 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
994 | |
995 | return ifind(sb, head, test, data, 1); |
996 | } |
997 | EXPORT_SYMBOL(ilookup5); |
998 | |
999 | /** |
1000 | * ilookup - search for an inode in the inode cache |
1001 | * @sb: super block of file system to search |
1002 | * @ino: inode number to search for |
1003 | * |
1004 | * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. |
1005 | * This is for file systems where the inode number is sufficient for unique |
1006 | * identification of an inode. |
1007 | * |
1008 | * If the inode is in the cache, the inode is returned with an incremented |
1009 | * reference count. |
1010 | * |
1011 | * Otherwise NULL is returned. |
1012 | */ |
1013 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1014 | { |
1015 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1016 | |
1017 | return ifind_fast(sb, head, ino); |
1018 | } |
1019 | EXPORT_SYMBOL(ilookup); |
1020 | |
1021 | /** |
1022 | * iget5_locked - obtain an inode from a mounted file system |
1023 | * @sb: super block of file system |
1024 | * @hashval: hash value (usually inode number) to get |
1025 | * @test: callback used for comparisons between inodes |
1026 | * @set: callback used to initialize a new struct inode |
1027 | * @data: opaque data pointer to pass to @test and @set |
1028 | * |
1029 | * iget5_locked() uses ifind() to search for the inode specified by @hashval |
1030 | * and @data in the inode cache and if present it is returned with an increased |
1031 | * reference count. This is a generalized version of iget_locked() for file |
1032 | * systems where the inode number is not sufficient for unique identification |
1033 | * of an inode. |
1034 | * |
1035 | * If the inode is not in cache, get_new_inode() is called to allocate a new |
1036 | * inode and this is returned locked, hashed, and with the I_NEW flag set. The |
1037 | * file system gets to fill it in before unlocking it via unlock_new_inode(). |
1038 | * |
1039 | * Note both @test and @set are called with the inode_lock held, so can't sleep. |
1040 | */ |
1041 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
1042 | int (*test)(struct inode *, void *), |
1043 | int (*set)(struct inode *, void *), void *data) |
1044 | { |
1045 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1046 | struct inode *inode; |
1047 | |
1048 | inode = ifind(sb, head, test, data, 1); |
1049 | if (inode) |
1050 | return inode; |
1051 | /* |
1052 | * get_new_inode() will do the right thing, re-trying the search |
1053 | * in case it had to block at any point. |
1054 | */ |
1055 | return get_new_inode(sb, head, test, set, data); |
1056 | } |
1057 | EXPORT_SYMBOL(iget5_locked); |
1058 | |
1059 | /** |
1060 | * iget_locked - obtain an inode from a mounted file system |
1061 | * @sb: super block of file system |
1062 | * @ino: inode number to get |
1063 | * |
1064 | * iget_locked() uses ifind_fast() to search for the inode specified by @ino in |
1065 | * the inode cache and if present it is returned with an increased reference |
1066 | * count. This is for file systems where the inode number is sufficient for |
1067 | * unique identification of an inode. |
1068 | * |
1069 | * If the inode is not in cache, get_new_inode_fast() is called to allocate a |
1070 | * new inode and this is returned locked, hashed, and with the I_NEW flag set. |
1071 | * The file system gets to fill it in before unlocking it via |
1072 | * unlock_new_inode(). |
1073 | */ |
1074 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1075 | { |
1076 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1077 | struct inode *inode; |
1078 | |
1079 | inode = ifind_fast(sb, head, ino); |
1080 | if (inode) |
1081 | return inode; |
1082 | /* |
1083 | * get_new_inode_fast() will do the right thing, re-trying the search |
1084 | * in case it had to block at any point. |
1085 | */ |
1086 | return get_new_inode_fast(sb, head, ino); |
1087 | } |
1088 | EXPORT_SYMBOL(iget_locked); |
1089 | |
1090 | int insert_inode_locked(struct inode *inode) |
1091 | { |
1092 | struct super_block *sb = inode->i_sb; |
1093 | ino_t ino = inode->i_ino; |
1094 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1095 | |
1096 | inode->i_state |= I_LOCK|I_NEW; |
1097 | while (1) { |
1098 | struct hlist_node *node; |
1099 | struct inode *old = NULL; |
1100 | spin_lock(&inode_lock); |
1101 | hlist_for_each_entry(old, node, head, i_hash) { |
1102 | if (old->i_ino != ino) |
1103 | continue; |
1104 | if (old->i_sb != sb) |
1105 | continue; |
1106 | if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) |
1107 | continue; |
1108 | break; |
1109 | } |
1110 | if (likely(!node)) { |
1111 | hlist_add_head(&inode->i_hash, head); |
1112 | spin_unlock(&inode_lock); |
1113 | return 0; |
1114 | } |
1115 | __iget(old); |
1116 | spin_unlock(&inode_lock); |
1117 | wait_on_inode(old); |
1118 | if (unlikely(!hlist_unhashed(&old->i_hash))) { |
1119 | iput(old); |
1120 | return -EBUSY; |
1121 | } |
1122 | iput(old); |
1123 | } |
1124 | } |
1125 | EXPORT_SYMBOL(insert_inode_locked); |
1126 | |
1127 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1128 | int (*test)(struct inode *, void *), void *data) |
1129 | { |
1130 | struct super_block *sb = inode->i_sb; |
1131 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1132 | |
1133 | inode->i_state |= I_LOCK|I_NEW; |
1134 | |
1135 | while (1) { |
1136 | struct hlist_node *node; |
1137 | struct inode *old = NULL; |
1138 | |
1139 | spin_lock(&inode_lock); |
1140 | hlist_for_each_entry(old, node, head, i_hash) { |
1141 | if (old->i_sb != sb) |
1142 | continue; |
1143 | if (!test(old, data)) |
1144 | continue; |
1145 | if (old->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) |
1146 | continue; |
1147 | break; |
1148 | } |
1149 | if (likely(!node)) { |
1150 | hlist_add_head(&inode->i_hash, head); |
1151 | spin_unlock(&inode_lock); |
1152 | return 0; |
1153 | } |
1154 | __iget(old); |
1155 | spin_unlock(&inode_lock); |
1156 | wait_on_inode(old); |
1157 | if (unlikely(!hlist_unhashed(&old->i_hash))) { |
1158 | iput(old); |
1159 | return -EBUSY; |
1160 | } |
1161 | iput(old); |
1162 | } |
1163 | } |
1164 | EXPORT_SYMBOL(insert_inode_locked4); |
1165 | |
1166 | /** |
1167 | * __insert_inode_hash - hash an inode |
1168 | * @inode: unhashed inode |
1169 | * @hashval: unsigned long value used to locate this object in the |
1170 | * inode_hashtable. |
1171 | * |
1172 | * Add an inode to the inode hash for this superblock. |
1173 | */ |
1174 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
1175 | { |
1176 | struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); |
1177 | spin_lock(&inode_lock); |
1178 | hlist_add_head(&inode->i_hash, head); |
1179 | spin_unlock(&inode_lock); |
1180 | } |
1181 | EXPORT_SYMBOL(__insert_inode_hash); |
1182 | |
1183 | /** |
1184 | * remove_inode_hash - remove an inode from the hash |
1185 | * @inode: inode to unhash |
1186 | * |
1187 | * Remove an inode from the superblock. |
1188 | */ |
1189 | void remove_inode_hash(struct inode *inode) |
1190 | { |
1191 | spin_lock(&inode_lock); |
1192 | hlist_del_init(&inode->i_hash); |
1193 | spin_unlock(&inode_lock); |
1194 | } |
1195 | EXPORT_SYMBOL(remove_inode_hash); |
1196 | |
1197 | /* |
1198 | * Tell the filesystem that this inode is no longer of any interest and should |
1199 | * be completely destroyed. |
1200 | * |
1201 | * We leave the inode in the inode hash table until *after* the filesystem's |
1202 | * ->delete_inode completes. This ensures that an iget (such as nfsd might |
1203 | * instigate) will always find up-to-date information either in the hash or on |
1204 | * disk. |
1205 | * |
1206 | * I_FREEING is set so that no-one will take a new reference to the inode while |
1207 | * it is being deleted. |
1208 | */ |
1209 | void generic_delete_inode(struct inode *inode) |
1210 | { |
1211 | const struct super_operations *op = inode->i_sb->s_op; |
1212 | |
1213 | list_del_init(&inode->i_list); |
1214 | list_del_init(&inode->i_sb_list); |
1215 | WARN_ON(inode->i_state & I_NEW); |
1216 | inode->i_state |= I_FREEING; |
1217 | inodes_stat.nr_inodes--; |
1218 | spin_unlock(&inode_lock); |
1219 | |
1220 | security_inode_delete(inode); |
1221 | |
1222 | if (op->delete_inode) { |
1223 | void (*delete)(struct inode *) = op->delete_inode; |
1224 | if (!is_bad_inode(inode)) |
1225 | vfs_dq_init(inode); |
1226 | /* Filesystems implementing their own |
1227 | * s_op->delete_inode are required to call |
1228 | * truncate_inode_pages and clear_inode() |
1229 | * internally */ |
1230 | delete(inode); |
1231 | } else { |
1232 | truncate_inode_pages(&inode->i_data, 0); |
1233 | clear_inode(inode); |
1234 | } |
1235 | spin_lock(&inode_lock); |
1236 | hlist_del_init(&inode->i_hash); |
1237 | spin_unlock(&inode_lock); |
1238 | wake_up_inode(inode); |
1239 | BUG_ON(inode->i_state != I_CLEAR); |
1240 | destroy_inode(inode); |
1241 | } |
1242 | EXPORT_SYMBOL(generic_delete_inode); |
1243 | |
1244 | /** |
1245 | * generic_detach_inode - remove inode from inode lists |
1246 | * @inode: inode to remove |
1247 | * |
1248 | * Remove inode from inode lists, write it if it's dirty. This is just an |
1249 | * internal VFS helper exported for hugetlbfs. Do not use! |
1250 | * |
1251 | * Returns 1 if inode should be completely destroyed. |
1252 | */ |
1253 | int generic_detach_inode(struct inode *inode) |
1254 | { |
1255 | struct super_block *sb = inode->i_sb; |
1256 | |
1257 | if (!hlist_unhashed(&inode->i_hash)) { |
1258 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1259 | list_move(&inode->i_list, &inode_unused); |
1260 | inodes_stat.nr_unused++; |
1261 | if (sb->s_flags & MS_ACTIVE) { |
1262 | spin_unlock(&inode_lock); |
1263 | return 0; |
1264 | } |
1265 | WARN_ON(inode->i_state & I_NEW); |
1266 | inode->i_state |= I_WILL_FREE; |
1267 | spin_unlock(&inode_lock); |
1268 | write_inode_now(inode, 1); |
1269 | spin_lock(&inode_lock); |
1270 | WARN_ON(inode->i_state & I_NEW); |
1271 | inode->i_state &= ~I_WILL_FREE; |
1272 | inodes_stat.nr_unused--; |
1273 | hlist_del_init(&inode->i_hash); |
1274 | } |
1275 | list_del_init(&inode->i_list); |
1276 | list_del_init(&inode->i_sb_list); |
1277 | WARN_ON(inode->i_state & I_NEW); |
1278 | inode->i_state |= I_FREEING; |
1279 | inodes_stat.nr_inodes--; |
1280 | spin_unlock(&inode_lock); |
1281 | return 1; |
1282 | } |
1283 | EXPORT_SYMBOL_GPL(generic_detach_inode); |
1284 | |
1285 | static void generic_forget_inode(struct inode *inode) |
1286 | { |
1287 | if (!generic_detach_inode(inode)) |
1288 | return; |
1289 | if (inode->i_data.nrpages) |
1290 | truncate_inode_pages(&inode->i_data, 0); |
1291 | clear_inode(inode); |
1292 | wake_up_inode(inode); |
1293 | destroy_inode(inode); |
1294 | } |
1295 | |
1296 | /* |
1297 | * Normal UNIX filesystem behaviour: delete the |
1298 | * inode when the usage count drops to zero, and |
1299 | * i_nlink is zero. |
1300 | */ |
1301 | void generic_drop_inode(struct inode *inode) |
1302 | { |
1303 | if (!inode->i_nlink) |
1304 | generic_delete_inode(inode); |
1305 | else |
1306 | generic_forget_inode(inode); |
1307 | } |
1308 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1309 | |
1310 | /* |
1311 | * Called when we're dropping the last reference |
1312 | * to an inode. |
1313 | * |
1314 | * Call the FS "drop()" function, defaulting to |
1315 | * the legacy UNIX filesystem behaviour.. |
1316 | * |
1317 | * NOTE! NOTE! NOTE! We're called with the inode lock |
1318 | * held, and the drop function is supposed to release |
1319 | * the lock! |
1320 | */ |
1321 | static inline void iput_final(struct inode *inode) |
1322 | { |
1323 | const struct super_operations *op = inode->i_sb->s_op; |
1324 | void (*drop)(struct inode *) = generic_drop_inode; |
1325 | |
1326 | if (op && op->drop_inode) |
1327 | drop = op->drop_inode; |
1328 | drop(inode); |
1329 | } |
1330 | |
1331 | /** |
1332 | * iput - put an inode |
1333 | * @inode: inode to put |
1334 | * |
1335 | * Puts an inode, dropping its usage count. If the inode use count hits |
1336 | * zero, the inode is then freed and may also be destroyed. |
1337 | * |
1338 | * Consequently, iput() can sleep. |
1339 | */ |
1340 | void iput(struct inode *inode) |
1341 | { |
1342 | if (inode) { |
1343 | BUG_ON(inode->i_state == I_CLEAR); |
1344 | |
1345 | if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) |
1346 | iput_final(inode); |
1347 | } |
1348 | } |
1349 | EXPORT_SYMBOL(iput); |
1350 | |
1351 | /** |
1352 | * bmap - find a block number in a file |
1353 | * @inode: inode of file |
1354 | * @block: block to find |
1355 | * |
1356 | * Returns the block number on the device holding the inode that |
1357 | * is the disk block number for the block of the file requested. |
1358 | * That is, asked for block 4 of inode 1 the function will return the |
1359 | * disk block relative to the disk start that holds that block of the |
1360 | * file. |
1361 | */ |
1362 | sector_t bmap(struct inode *inode, sector_t block) |
1363 | { |
1364 | sector_t res = 0; |
1365 | if (inode->i_mapping->a_ops->bmap) |
1366 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
1367 | return res; |
1368 | } |
1369 | EXPORT_SYMBOL(bmap); |
1370 | |
1371 | /* |
1372 | * With relative atime, only update atime if the previous atime is |
1373 | * earlier than either the ctime or mtime or if at least a day has |
1374 | * passed since the last atime update. |
1375 | */ |
1376 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1377 | struct timespec now) |
1378 | { |
1379 | |
1380 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1381 | return 1; |
1382 | /* |
1383 | * Is mtime younger than atime? If yes, update atime: |
1384 | */ |
1385 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
1386 | return 1; |
1387 | /* |
1388 | * Is ctime younger than atime? If yes, update atime: |
1389 | */ |
1390 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
1391 | return 1; |
1392 | |
1393 | /* |
1394 | * Is the previous atime value older than a day? If yes, |
1395 | * update atime: |
1396 | */ |
1397 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
1398 | return 1; |
1399 | /* |
1400 | * Good, we can skip the atime update: |
1401 | */ |
1402 | return 0; |
1403 | } |
1404 | |
1405 | /** |
1406 | * touch_atime - update the access time |
1407 | * @mnt: mount the inode is accessed on |
1408 | * @dentry: dentry accessed |
1409 | * |
1410 | * Update the accessed time on an inode and mark it for writeback. |
1411 | * This function automatically handles read only file systems and media, |
1412 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1413 | */ |
1414 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1415 | { |
1416 | struct inode *inode = dentry->d_inode; |
1417 | struct timespec now; |
1418 | |
1419 | if (inode->i_flags & S_NOATIME) |
1420 | return; |
1421 | if (IS_NOATIME(inode)) |
1422 | return; |
1423 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1424 | return; |
1425 | |
1426 | if (mnt->mnt_flags & MNT_NOATIME) |
1427 | return; |
1428 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1429 | return; |
1430 | |
1431 | now = current_fs_time(inode->i_sb); |
1432 | |
1433 | if (!relatime_need_update(mnt, inode, now)) |
1434 | return; |
1435 | |
1436 | if (timespec_equal(&inode->i_atime, &now)) |
1437 | return; |
1438 | |
1439 | if (mnt_want_write(mnt)) |
1440 | return; |
1441 | |
1442 | inode->i_atime = now; |
1443 | mark_inode_dirty_sync(inode); |
1444 | mnt_drop_write(mnt); |
1445 | } |
1446 | EXPORT_SYMBOL(touch_atime); |
1447 | |
1448 | /** |
1449 | * file_update_time - update mtime and ctime time |
1450 | * @file: file accessed |
1451 | * |
1452 | * Update the mtime and ctime members of an inode and mark the inode |
1453 | * for writeback. Note that this function is meant exclusively for |
1454 | * usage in the file write path of filesystems, and filesystems may |
1455 | * choose to explicitly ignore update via this function with the |
1456 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
1457 | * timestamps are handled by the server. |
1458 | */ |
1459 | |
1460 | void file_update_time(struct file *file) |
1461 | { |
1462 | struct inode *inode = file->f_path.dentry->d_inode; |
1463 | struct timespec now; |
1464 | enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0; |
1465 | |
1466 | /* First try to exhaust all avenues to not sync */ |
1467 | if (IS_NOCMTIME(inode)) |
1468 | return; |
1469 | |
1470 | now = current_fs_time(inode->i_sb); |
1471 | if (!timespec_equal(&inode->i_mtime, &now)) |
1472 | sync_it = S_MTIME; |
1473 | |
1474 | if (!timespec_equal(&inode->i_ctime, &now)) |
1475 | sync_it |= S_CTIME; |
1476 | |
1477 | if (IS_I_VERSION(inode)) |
1478 | sync_it |= S_VERSION; |
1479 | |
1480 | if (!sync_it) |
1481 | return; |
1482 | |
1483 | /* Finally allowed to write? Takes lock. */ |
1484 | if (mnt_want_write_file(file)) |
1485 | return; |
1486 | |
1487 | /* Only change inode inside the lock region */ |
1488 | if (sync_it & S_VERSION) |
1489 | inode_inc_iversion(inode); |
1490 | if (sync_it & S_CTIME) |
1491 | inode->i_ctime = now; |
1492 | if (sync_it & S_MTIME) |
1493 | inode->i_mtime = now; |
1494 | mark_inode_dirty_sync(inode); |
1495 | mnt_drop_write(file->f_path.mnt); |
1496 | } |
1497 | EXPORT_SYMBOL(file_update_time); |
1498 | |
1499 | int inode_needs_sync(struct inode *inode) |
1500 | { |
1501 | if (IS_SYNC(inode)) |
1502 | return 1; |
1503 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
1504 | return 1; |
1505 | return 0; |
1506 | } |
1507 | EXPORT_SYMBOL(inode_needs_sync); |
1508 | |
1509 | int inode_wait(void *word) |
1510 | { |
1511 | schedule(); |
1512 | return 0; |
1513 | } |
1514 | EXPORT_SYMBOL(inode_wait); |
1515 | |
1516 | /* |
1517 | * If we try to find an inode in the inode hash while it is being |
1518 | * deleted, we have to wait until the filesystem completes its |
1519 | * deletion before reporting that it isn't found. This function waits |
1520 | * until the deletion _might_ have completed. Callers are responsible |
1521 | * to recheck inode state. |
1522 | * |
1523 | * It doesn't matter if I_LOCK is not set initially, a call to |
1524 | * wake_up_inode() after removing from the hash list will DTRT. |
1525 | * |
1526 | * This is called with inode_lock held. |
1527 | */ |
1528 | static void __wait_on_freeing_inode(struct inode *inode) |
1529 | { |
1530 | wait_queue_head_t *wq; |
1531 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK); |
1532 | wq = bit_waitqueue(&inode->i_state, __I_LOCK); |
1533 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
1534 | spin_unlock(&inode_lock); |
1535 | schedule(); |
1536 | finish_wait(wq, &wait.wait); |
1537 | spin_lock(&inode_lock); |
1538 | } |
1539 | |
1540 | static __initdata unsigned long ihash_entries; |
1541 | static int __init set_ihash_entries(char *str) |
1542 | { |
1543 | if (!str) |
1544 | return 0; |
1545 | ihash_entries = simple_strtoul(str, &str, 0); |
1546 | return 1; |
1547 | } |
1548 | __setup("ihash_entries=", set_ihash_entries); |
1549 | |
1550 | /* |
1551 | * Initialize the waitqueues and inode hash table. |
1552 | */ |
1553 | void __init inode_init_early(void) |
1554 | { |
1555 | int loop; |
1556 | |
1557 | /* If hashes are distributed across NUMA nodes, defer |
1558 | * hash allocation until vmalloc space is available. |
1559 | */ |
1560 | if (hashdist) |
1561 | return; |
1562 | |
1563 | inode_hashtable = |
1564 | alloc_large_system_hash("Inode-cache", |
1565 | sizeof(struct hlist_head), |
1566 | ihash_entries, |
1567 | 14, |
1568 | HASH_EARLY, |
1569 | &i_hash_shift, |
1570 | &i_hash_mask, |
1571 | 0); |
1572 | |
1573 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1574 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1575 | } |
1576 | |
1577 | void __init inode_init(void) |
1578 | { |
1579 | int loop; |
1580 | |
1581 | /* inode slab cache */ |
1582 | inode_cachep = kmem_cache_create("inode_cache", |
1583 | sizeof(struct inode), |
1584 | 0, |
1585 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
1586 | SLAB_MEM_SPREAD), |
1587 | init_once); |
1588 | register_shrinker(&icache_shrinker); |
1589 | |
1590 | /* Hash may have been set up in inode_init_early */ |
1591 | if (!hashdist) |
1592 | return; |
1593 | |
1594 | inode_hashtable = |
1595 | alloc_large_system_hash("Inode-cache", |
1596 | sizeof(struct hlist_head), |
1597 | ihash_entries, |
1598 | 14, |
1599 | 0, |
1600 | &i_hash_shift, |
1601 | &i_hash_mask, |
1602 | 0); |
1603 | |
1604 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1605 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1606 | } |
1607 | |
1608 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
1609 | { |
1610 | inode->i_mode = mode; |
1611 | if (S_ISCHR(mode)) { |
1612 | inode->i_fop = &def_chr_fops; |
1613 | inode->i_rdev = rdev; |
1614 | } else if (S_ISBLK(mode)) { |
1615 | inode->i_fop = &def_blk_fops; |
1616 | inode->i_rdev = rdev; |
1617 | } else if (S_ISFIFO(mode)) |
1618 | inode->i_fop = &def_fifo_fops; |
1619 | else if (S_ISSOCK(mode)) |
1620 | inode->i_fop = &bad_sock_fops; |
1621 | else |
1622 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
1623 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
1624 | inode->i_ino); |
1625 | } |
1626 | EXPORT_SYMBOL(init_special_inode); |
1627 |
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