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1 | /* |
2 | * (C) 1997 Linus Torvalds |
3 | * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation) |
4 | */ |
5 | #include <linux/fs.h> |
6 | #include <linux/mm.h> |
7 | #include <linux/dcache.h> |
8 | #include <linux/init.h> |
9 | #include <linux/slab.h> |
10 | #include <linux/writeback.h> |
11 | #include <linux/module.h> |
12 | #include <linux/backing-dev.h> |
13 | #include <linux/wait.h> |
14 | #include <linux/rwsem.h> |
15 | #include <linux/hash.h> |
16 | #include <linux/swap.h> |
17 | #include <linux/security.h> |
18 | #include <linux/pagemap.h> |
19 | #include <linux/cdev.h> |
20 | #include <linux/bootmem.h> |
21 | #include <linux/fsnotify.h> |
22 | #include <linux/mount.h> |
23 | #include <linux/async.h> |
24 | #include <linux/posix_acl.h> |
25 | #include <linux/prefetch.h> |
26 | #include <linux/ima.h> |
27 | #include <linux/cred.h> |
28 | #include <linux/buffer_head.h> /* for inode_has_buffers */ |
29 | #include "internal.h" |
30 | |
31 | /* |
32 | * Inode locking rules: |
33 | * |
34 | * inode->i_lock protects: |
35 | * inode->i_state, inode->i_hash, __iget() |
36 | * inode_lru_lock protects: |
37 | * inode_lru, inode->i_lru |
38 | * inode_sb_list_lock protects: |
39 | * sb->s_inodes, inode->i_sb_list |
40 | * inode_wb_list_lock protects: |
41 | * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list |
42 | * inode_hash_lock protects: |
43 | * inode_hashtable, inode->i_hash |
44 | * |
45 | * Lock ordering: |
46 | * |
47 | * inode_sb_list_lock |
48 | * inode->i_lock |
49 | * inode_lru_lock |
50 | * |
51 | * inode_wb_list_lock |
52 | * inode->i_lock |
53 | * |
54 | * inode_hash_lock |
55 | * inode_sb_list_lock |
56 | * inode->i_lock |
57 | * |
58 | * iunique_lock |
59 | * inode_hash_lock |
60 | */ |
61 | |
62 | static unsigned int i_hash_mask __read_mostly; |
63 | static unsigned int i_hash_shift __read_mostly; |
64 | static struct hlist_head *inode_hashtable __read_mostly; |
65 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
66 | |
67 | static LIST_HEAD(inode_lru); |
68 | static DEFINE_SPINLOCK(inode_lru_lock); |
69 | |
70 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock); |
71 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_wb_list_lock); |
72 | |
73 | /* |
74 | * iprune_sem provides exclusion between the icache shrinking and the |
75 | * umount path. |
76 | * |
77 | * We don't actually need it to protect anything in the umount path, |
78 | * but only need to cycle through it to make sure any inode that |
79 | * prune_icache took off the LRU list has been fully torn down by the |
80 | * time we are past evict_inodes. |
81 | */ |
82 | static DECLARE_RWSEM(iprune_sem); |
83 | |
84 | /* |
85 | * Empty aops. Can be used for the cases where the user does not |
86 | * define any of the address_space operations. |
87 | */ |
88 | const struct address_space_operations empty_aops = { |
89 | }; |
90 | EXPORT_SYMBOL(empty_aops); |
91 | |
92 | /* |
93 | * Statistics gathering.. |
94 | */ |
95 | struct inodes_stat_t inodes_stat; |
96 | |
97 | static DEFINE_PER_CPU(unsigned int, nr_inodes); |
98 | |
99 | static struct kmem_cache *inode_cachep __read_mostly; |
100 | |
101 | static int get_nr_inodes(void) |
102 | { |
103 | int i; |
104 | int sum = 0; |
105 | for_each_possible_cpu(i) |
106 | sum += per_cpu(nr_inodes, i); |
107 | return sum < 0 ? 0 : sum; |
108 | } |
109 | |
110 | static inline int get_nr_inodes_unused(void) |
111 | { |
112 | return inodes_stat.nr_unused; |
113 | } |
114 | |
115 | int get_nr_dirty_inodes(void) |
116 | { |
117 | /* not actually dirty inodes, but a wild approximation */ |
118 | int nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
119 | return nr_dirty > 0 ? nr_dirty : 0; |
120 | } |
121 | |
122 | /* |
123 | * Handle nr_inode sysctl |
124 | */ |
125 | #ifdef CONFIG_SYSCTL |
126 | int proc_nr_inodes(ctl_table *table, int write, |
127 | void __user *buffer, size_t *lenp, loff_t *ppos) |
128 | { |
129 | inodes_stat.nr_inodes = get_nr_inodes(); |
130 | return proc_dointvec(table, write, buffer, lenp, ppos); |
131 | } |
132 | #endif |
133 | |
134 | /** |
135 | * inode_init_always - perform inode structure intialisation |
136 | * @sb: superblock inode belongs to |
137 | * @inode: inode to initialise |
138 | * |
139 | * These are initializations that need to be done on every inode |
140 | * allocation as the fields are not initialised by slab allocation. |
141 | */ |
142 | int inode_init_always(struct super_block *sb, struct inode *inode) |
143 | { |
144 | static const struct inode_operations empty_iops; |
145 | static const struct file_operations empty_fops; |
146 | struct address_space *const mapping = &inode->i_data; |
147 | |
148 | inode->i_sb = sb; |
149 | inode->i_blkbits = sb->s_blocksize_bits; |
150 | inode->i_flags = 0; |
151 | atomic_set(&inode->i_count, 1); |
152 | inode->i_op = &empty_iops; |
153 | inode->i_fop = &empty_fops; |
154 | inode->i_nlink = 1; |
155 | inode->i_uid = 0; |
156 | inode->i_gid = 0; |
157 | atomic_set(&inode->i_writecount, 0); |
158 | inode->i_size = 0; |
159 | inode->i_blocks = 0; |
160 | inode->i_bytes = 0; |
161 | inode->i_generation = 0; |
162 | #ifdef CONFIG_QUOTA |
163 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
164 | #endif |
165 | inode->i_pipe = NULL; |
166 | inode->i_bdev = NULL; |
167 | inode->i_cdev = NULL; |
168 | inode->i_rdev = 0; |
169 | inode->dirtied_when = 0; |
170 | |
171 | if (security_inode_alloc(inode)) |
172 | goto out; |
173 | spin_lock_init(&inode->i_lock); |
174 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
175 | |
176 | mutex_init(&inode->i_mutex); |
177 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
178 | |
179 | init_rwsem(&inode->i_alloc_sem); |
180 | lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); |
181 | |
182 | mapping->a_ops = &empty_aops; |
183 | mapping->host = inode; |
184 | mapping->flags = 0; |
185 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
186 | mapping->assoc_mapping = NULL; |
187 | mapping->backing_dev_info = &default_backing_dev_info; |
188 | mapping->writeback_index = 0; |
189 | |
190 | /* |
191 | * If the block_device provides a backing_dev_info for client |
192 | * inodes then use that. Otherwise the inode share the bdev's |
193 | * backing_dev_info. |
194 | */ |
195 | if (sb->s_bdev) { |
196 | struct backing_dev_info *bdi; |
197 | |
198 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
199 | mapping->backing_dev_info = bdi; |
200 | } |
201 | inode->i_private = NULL; |
202 | inode->i_mapping = mapping; |
203 | #ifdef CONFIG_FS_POSIX_ACL |
204 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
205 | #endif |
206 | |
207 | #ifdef CONFIG_FSNOTIFY |
208 | inode->i_fsnotify_mask = 0; |
209 | #endif |
210 | |
211 | this_cpu_inc(nr_inodes); |
212 | |
213 | return 0; |
214 | out: |
215 | return -ENOMEM; |
216 | } |
217 | EXPORT_SYMBOL(inode_init_always); |
218 | |
219 | static struct inode *alloc_inode(struct super_block *sb) |
220 | { |
221 | struct inode *inode; |
222 | |
223 | if (sb->s_op->alloc_inode) |
224 | inode = sb->s_op->alloc_inode(sb); |
225 | else |
226 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
227 | |
228 | if (!inode) |
229 | return NULL; |
230 | |
231 | if (unlikely(inode_init_always(sb, inode))) { |
232 | if (inode->i_sb->s_op->destroy_inode) |
233 | inode->i_sb->s_op->destroy_inode(inode); |
234 | else |
235 | kmem_cache_free(inode_cachep, inode); |
236 | return NULL; |
237 | } |
238 | |
239 | return inode; |
240 | } |
241 | |
242 | void free_inode_nonrcu(struct inode *inode) |
243 | { |
244 | kmem_cache_free(inode_cachep, inode); |
245 | } |
246 | EXPORT_SYMBOL(free_inode_nonrcu); |
247 | |
248 | void __destroy_inode(struct inode *inode) |
249 | { |
250 | BUG_ON(inode_has_buffers(inode)); |
251 | security_inode_free(inode); |
252 | fsnotify_inode_delete(inode); |
253 | #ifdef CONFIG_FS_POSIX_ACL |
254 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
255 | posix_acl_release(inode->i_acl); |
256 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
257 | posix_acl_release(inode->i_default_acl); |
258 | #endif |
259 | this_cpu_dec(nr_inodes); |
260 | } |
261 | EXPORT_SYMBOL(__destroy_inode); |
262 | |
263 | static void i_callback(struct rcu_head *head) |
264 | { |
265 | struct inode *inode = container_of(head, struct inode, i_rcu); |
266 | INIT_LIST_HEAD(&inode->i_dentry); |
267 | kmem_cache_free(inode_cachep, inode); |
268 | } |
269 | |
270 | static void destroy_inode(struct inode *inode) |
271 | { |
272 | BUG_ON(!list_empty(&inode->i_lru)); |
273 | __destroy_inode(inode); |
274 | if (inode->i_sb->s_op->destroy_inode) |
275 | inode->i_sb->s_op->destroy_inode(inode); |
276 | else |
277 | call_rcu(&inode->i_rcu, i_callback); |
278 | } |
279 | |
280 | void address_space_init_once(struct address_space *mapping) |
281 | { |
282 | memset(mapping, 0, sizeof(*mapping)); |
283 | INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); |
284 | spin_lock_init(&mapping->tree_lock); |
285 | mutex_init(&mapping->i_mmap_mutex); |
286 | INIT_LIST_HEAD(&mapping->private_list); |
287 | spin_lock_init(&mapping->private_lock); |
288 | INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap); |
289 | INIT_LIST_HEAD(&mapping->i_mmap_nonlinear); |
290 | } |
291 | EXPORT_SYMBOL(address_space_init_once); |
292 | |
293 | /* |
294 | * These are initializations that only need to be done |
295 | * once, because the fields are idempotent across use |
296 | * of the inode, so let the slab aware of that. |
297 | */ |
298 | void inode_init_once(struct inode *inode) |
299 | { |
300 | memset(inode, 0, sizeof(*inode)); |
301 | INIT_HLIST_NODE(&inode->i_hash); |
302 | INIT_LIST_HEAD(&inode->i_dentry); |
303 | INIT_LIST_HEAD(&inode->i_devices); |
304 | INIT_LIST_HEAD(&inode->i_wb_list); |
305 | INIT_LIST_HEAD(&inode->i_lru); |
306 | address_space_init_once(&inode->i_data); |
307 | i_size_ordered_init(inode); |
308 | #ifdef CONFIG_FSNOTIFY |
309 | INIT_HLIST_HEAD(&inode->i_fsnotify_marks); |
310 | #endif |
311 | } |
312 | EXPORT_SYMBOL(inode_init_once); |
313 | |
314 | static void init_once(void *foo) |
315 | { |
316 | struct inode *inode = (struct inode *) foo; |
317 | |
318 | inode_init_once(inode); |
319 | } |
320 | |
321 | /* |
322 | * inode->i_lock must be held |
323 | */ |
324 | void __iget(struct inode *inode) |
325 | { |
326 | atomic_inc(&inode->i_count); |
327 | } |
328 | |
329 | /* |
330 | * get additional reference to inode; caller must already hold one. |
331 | */ |
332 | void ihold(struct inode *inode) |
333 | { |
334 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
335 | } |
336 | EXPORT_SYMBOL(ihold); |
337 | |
338 | static void inode_lru_list_add(struct inode *inode) |
339 | { |
340 | spin_lock(&inode_lru_lock); |
341 | if (list_empty(&inode->i_lru)) { |
342 | list_add(&inode->i_lru, &inode_lru); |
343 | inodes_stat.nr_unused++; |
344 | } |
345 | spin_unlock(&inode_lru_lock); |
346 | } |
347 | |
348 | static void inode_lru_list_del(struct inode *inode) |
349 | { |
350 | spin_lock(&inode_lru_lock); |
351 | if (!list_empty(&inode->i_lru)) { |
352 | list_del_init(&inode->i_lru); |
353 | inodes_stat.nr_unused--; |
354 | } |
355 | spin_unlock(&inode_lru_lock); |
356 | } |
357 | |
358 | /** |
359 | * inode_sb_list_add - add inode to the superblock list of inodes |
360 | * @inode: inode to add |
361 | */ |
362 | void inode_sb_list_add(struct inode *inode) |
363 | { |
364 | spin_lock(&inode_sb_list_lock); |
365 | list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
366 | spin_unlock(&inode_sb_list_lock); |
367 | } |
368 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
369 | |
370 | static inline void inode_sb_list_del(struct inode *inode) |
371 | { |
372 | spin_lock(&inode_sb_list_lock); |
373 | list_del_init(&inode->i_sb_list); |
374 | spin_unlock(&inode_sb_list_lock); |
375 | } |
376 | |
377 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
378 | { |
379 | unsigned long tmp; |
380 | |
381 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
382 | L1_CACHE_BYTES; |
383 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
384 | return tmp & i_hash_mask; |
385 | } |
386 | |
387 | /** |
388 | * __insert_inode_hash - hash an inode |
389 | * @inode: unhashed inode |
390 | * @hashval: unsigned long value used to locate this object in the |
391 | * inode_hashtable. |
392 | * |
393 | * Add an inode to the inode hash for this superblock. |
394 | */ |
395 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
396 | { |
397 | struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
398 | |
399 | spin_lock(&inode_hash_lock); |
400 | spin_lock(&inode->i_lock); |
401 | hlist_add_head(&inode->i_hash, b); |
402 | spin_unlock(&inode->i_lock); |
403 | spin_unlock(&inode_hash_lock); |
404 | } |
405 | EXPORT_SYMBOL(__insert_inode_hash); |
406 | |
407 | /** |
408 | * remove_inode_hash - remove an inode from the hash |
409 | * @inode: inode to unhash |
410 | * |
411 | * Remove an inode from the superblock. |
412 | */ |
413 | void remove_inode_hash(struct inode *inode) |
414 | { |
415 | spin_lock(&inode_hash_lock); |
416 | spin_lock(&inode->i_lock); |
417 | hlist_del_init(&inode->i_hash); |
418 | spin_unlock(&inode->i_lock); |
419 | spin_unlock(&inode_hash_lock); |
420 | } |
421 | EXPORT_SYMBOL(remove_inode_hash); |
422 | |
423 | void end_writeback(struct inode *inode) |
424 | { |
425 | might_sleep(); |
426 | /* |
427 | * We have to cycle tree_lock here because reclaim can be still in the |
428 | * process of removing the last page (in __delete_from_page_cache()) |
429 | * and we must not free mapping under it. |
430 | */ |
431 | spin_lock_irq(&inode->i_data.tree_lock); |
432 | BUG_ON(inode->i_data.nrpages); |
433 | spin_unlock_irq(&inode->i_data.tree_lock); |
434 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
435 | BUG_ON(!(inode->i_state & I_FREEING)); |
436 | BUG_ON(inode->i_state & I_CLEAR); |
437 | inode_sync_wait(inode); |
438 | /* don't need i_lock here, no concurrent mods to i_state */ |
439 | inode->i_state = I_FREEING | I_CLEAR; |
440 | } |
441 | EXPORT_SYMBOL(end_writeback); |
442 | |
443 | /* |
444 | * Free the inode passed in, removing it from the lists it is still connected |
445 | * to. We remove any pages still attached to the inode and wait for any IO that |
446 | * is still in progress before finally destroying the inode. |
447 | * |
448 | * An inode must already be marked I_FREEING so that we avoid the inode being |
449 | * moved back onto lists if we race with other code that manipulates the lists |
450 | * (e.g. writeback_single_inode). The caller is responsible for setting this. |
451 | * |
452 | * An inode must already be removed from the LRU list before being evicted from |
453 | * the cache. This should occur atomically with setting the I_FREEING state |
454 | * flag, so no inodes here should ever be on the LRU when being evicted. |
455 | */ |
456 | static void evict(struct inode *inode) |
457 | { |
458 | const struct super_operations *op = inode->i_sb->s_op; |
459 | |
460 | BUG_ON(!(inode->i_state & I_FREEING)); |
461 | BUG_ON(!list_empty(&inode->i_lru)); |
462 | |
463 | inode_wb_list_del(inode); |
464 | inode_sb_list_del(inode); |
465 | |
466 | if (op->evict_inode) { |
467 | op->evict_inode(inode); |
468 | } else { |
469 | if (inode->i_data.nrpages) |
470 | truncate_inode_pages(&inode->i_data, 0); |
471 | end_writeback(inode); |
472 | } |
473 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
474 | bd_forget(inode); |
475 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
476 | cd_forget(inode); |
477 | |
478 | remove_inode_hash(inode); |
479 | |
480 | spin_lock(&inode->i_lock); |
481 | wake_up_bit(&inode->i_state, __I_NEW); |
482 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
483 | spin_unlock(&inode->i_lock); |
484 | |
485 | destroy_inode(inode); |
486 | } |
487 | |
488 | /* |
489 | * dispose_list - dispose of the contents of a local list |
490 | * @head: the head of the list to free |
491 | * |
492 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
493 | * need to worry about list corruption and SMP locks. |
494 | */ |
495 | static void dispose_list(struct list_head *head) |
496 | { |
497 | while (!list_empty(head)) { |
498 | struct inode *inode; |
499 | |
500 | inode = list_first_entry(head, struct inode, i_lru); |
501 | list_del_init(&inode->i_lru); |
502 | |
503 | evict(inode); |
504 | } |
505 | } |
506 | |
507 | /** |
508 | * evict_inodes - evict all evictable inodes for a superblock |
509 | * @sb: superblock to operate on |
510 | * |
511 | * Make sure that no inodes with zero refcount are retained. This is |
512 | * called by superblock shutdown after having MS_ACTIVE flag removed, |
513 | * so any inode reaching zero refcount during or after that call will |
514 | * be immediately evicted. |
515 | */ |
516 | void evict_inodes(struct super_block *sb) |
517 | { |
518 | struct inode *inode, *next; |
519 | LIST_HEAD(dispose); |
520 | |
521 | spin_lock(&inode_sb_list_lock); |
522 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
523 | if (atomic_read(&inode->i_count)) |
524 | continue; |
525 | |
526 | spin_lock(&inode->i_lock); |
527 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
528 | spin_unlock(&inode->i_lock); |
529 | continue; |
530 | } |
531 | |
532 | inode->i_state |= I_FREEING; |
533 | inode_lru_list_del(inode); |
534 | spin_unlock(&inode->i_lock); |
535 | list_add(&inode->i_lru, &dispose); |
536 | } |
537 | spin_unlock(&inode_sb_list_lock); |
538 | |
539 | dispose_list(&dispose); |
540 | |
541 | /* |
542 | * Cycle through iprune_sem to make sure any inode that prune_icache |
543 | * moved off the list before we took the lock has been fully torn |
544 | * down. |
545 | */ |
546 | down_write(&iprune_sem); |
547 | up_write(&iprune_sem); |
548 | } |
549 | |
550 | /** |
551 | * invalidate_inodes - attempt to free all inodes on a superblock |
552 | * @sb: superblock to operate on |
553 | * @kill_dirty: flag to guide handling of dirty inodes |
554 | * |
555 | * Attempts to free all inodes for a given superblock. If there were any |
556 | * busy inodes return a non-zero value, else zero. |
557 | * If @kill_dirty is set, discard dirty inodes too, otherwise treat |
558 | * them as busy. |
559 | */ |
560 | int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
561 | { |
562 | int busy = 0; |
563 | struct inode *inode, *next; |
564 | LIST_HEAD(dispose); |
565 | |
566 | spin_lock(&inode_sb_list_lock); |
567 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
568 | spin_lock(&inode->i_lock); |
569 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
570 | spin_unlock(&inode->i_lock); |
571 | continue; |
572 | } |
573 | if (inode->i_state & I_DIRTY && !kill_dirty) { |
574 | spin_unlock(&inode->i_lock); |
575 | busy = 1; |
576 | continue; |
577 | } |
578 | if (atomic_read(&inode->i_count)) { |
579 | spin_unlock(&inode->i_lock); |
580 | busy = 1; |
581 | continue; |
582 | } |
583 | |
584 | inode->i_state |= I_FREEING; |
585 | inode_lru_list_del(inode); |
586 | spin_unlock(&inode->i_lock); |
587 | list_add(&inode->i_lru, &dispose); |
588 | } |
589 | spin_unlock(&inode_sb_list_lock); |
590 | |
591 | dispose_list(&dispose); |
592 | |
593 | return busy; |
594 | } |
595 | |
596 | static int can_unuse(struct inode *inode) |
597 | { |
598 | if (inode->i_state & ~I_REFERENCED) |
599 | return 0; |
600 | if (inode_has_buffers(inode)) |
601 | return 0; |
602 | if (atomic_read(&inode->i_count)) |
603 | return 0; |
604 | if (inode->i_data.nrpages) |
605 | return 0; |
606 | return 1; |
607 | } |
608 | |
609 | /* |
610 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to a |
611 | * temporary list and then are freed outside inode_lru_lock by dispose_list(). |
612 | * |
613 | * Any inodes which are pinned purely because of attached pagecache have their |
614 | * pagecache removed. If the inode has metadata buffers attached to |
615 | * mapping->private_list then try to remove them. |
616 | * |
617 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
618 | * used recently - the flag is set in iput_final(). When we encounter such an |
619 | * inode, clear the flag and move it to the back of the LRU so it gets another |
620 | * pass through the LRU before it gets reclaimed. This is necessary because of |
621 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
622 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
623 | * with this flag set because they are the inodes that are out of order. |
624 | */ |
625 | static void prune_icache(int nr_to_scan) |
626 | { |
627 | LIST_HEAD(freeable); |
628 | int nr_scanned; |
629 | unsigned long reap = 0; |
630 | |
631 | down_read(&iprune_sem); |
632 | spin_lock(&inode_lru_lock); |
633 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { |
634 | struct inode *inode; |
635 | |
636 | if (list_empty(&inode_lru)) |
637 | break; |
638 | |
639 | inode = list_entry(inode_lru.prev, struct inode, i_lru); |
640 | |
641 | /* |
642 | * we are inverting the inode_lru_lock/inode->i_lock here, |
643 | * so use a trylock. If we fail to get the lock, just move the |
644 | * inode to the back of the list so we don't spin on it. |
645 | */ |
646 | if (!spin_trylock(&inode->i_lock)) { |
647 | list_move(&inode->i_lru, &inode_lru); |
648 | continue; |
649 | } |
650 | |
651 | /* |
652 | * Referenced or dirty inodes are still in use. Give them |
653 | * another pass through the LRU as we canot reclaim them now. |
654 | */ |
655 | if (atomic_read(&inode->i_count) || |
656 | (inode->i_state & ~I_REFERENCED)) { |
657 | list_del_init(&inode->i_lru); |
658 | spin_unlock(&inode->i_lock); |
659 | inodes_stat.nr_unused--; |
660 | continue; |
661 | } |
662 | |
663 | /* recently referenced inodes get one more pass */ |
664 | if (inode->i_state & I_REFERENCED) { |
665 | inode->i_state &= ~I_REFERENCED; |
666 | list_move(&inode->i_lru, &inode_lru); |
667 | spin_unlock(&inode->i_lock); |
668 | continue; |
669 | } |
670 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
671 | __iget(inode); |
672 | spin_unlock(&inode->i_lock); |
673 | spin_unlock(&inode_lru_lock); |
674 | if (remove_inode_buffers(inode)) |
675 | reap += invalidate_mapping_pages(&inode->i_data, |
676 | 0, -1); |
677 | iput(inode); |
678 | spin_lock(&inode_lru_lock); |
679 | |
680 | if (inode != list_entry(inode_lru.next, |
681 | struct inode, i_lru)) |
682 | continue; /* wrong inode or list_empty */ |
683 | /* avoid lock inversions with trylock */ |
684 | if (!spin_trylock(&inode->i_lock)) |
685 | continue; |
686 | if (!can_unuse(inode)) { |
687 | spin_unlock(&inode->i_lock); |
688 | continue; |
689 | } |
690 | } |
691 | WARN_ON(inode->i_state & I_NEW); |
692 | inode->i_state |= I_FREEING; |
693 | spin_unlock(&inode->i_lock); |
694 | |
695 | list_move(&inode->i_lru, &freeable); |
696 | inodes_stat.nr_unused--; |
697 | } |
698 | if (current_is_kswapd()) |
699 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
700 | else |
701 | __count_vm_events(PGINODESTEAL, reap); |
702 | spin_unlock(&inode_lru_lock); |
703 | |
704 | dispose_list(&freeable); |
705 | up_read(&iprune_sem); |
706 | } |
707 | |
708 | /* |
709 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, |
710 | * "unused" means that no dentries are referring to the inodes: the files are |
711 | * not open and the dcache references to those inodes have already been |
712 | * reclaimed. |
713 | * |
714 | * This function is passed the number of inodes to scan, and it returns the |
715 | * total number of remaining possibly-reclaimable inodes. |
716 | */ |
717 | static int shrink_icache_memory(struct shrinker *shrink, |
718 | struct shrink_control *sc) |
719 | { |
720 | int nr = sc->nr_to_scan; |
721 | gfp_t gfp_mask = sc->gfp_mask; |
722 | |
723 | if (nr) { |
724 | /* |
725 | * Nasty deadlock avoidance. We may hold various FS locks, |
726 | * and we don't want to recurse into the FS that called us |
727 | * in clear_inode() and friends.. |
728 | */ |
729 | if (!(gfp_mask & __GFP_FS)) |
730 | return -1; |
731 | prune_icache(nr); |
732 | } |
733 | return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure; |
734 | } |
735 | |
736 | static struct shrinker icache_shrinker = { |
737 | .shrink = shrink_icache_memory, |
738 | .seeks = DEFAULT_SEEKS, |
739 | }; |
740 | |
741 | static void __wait_on_freeing_inode(struct inode *inode); |
742 | /* |
743 | * Called with the inode lock held. |
744 | */ |
745 | static struct inode *find_inode(struct super_block *sb, |
746 | struct hlist_head *head, |
747 | int (*test)(struct inode *, void *), |
748 | void *data) |
749 | { |
750 | struct hlist_node *node; |
751 | struct inode *inode = NULL; |
752 | |
753 | repeat: |
754 | hlist_for_each_entry(inode, node, head, i_hash) { |
755 | spin_lock(&inode->i_lock); |
756 | if (inode->i_sb != sb) { |
757 | spin_unlock(&inode->i_lock); |
758 | continue; |
759 | } |
760 | if (!test(inode, data)) { |
761 | spin_unlock(&inode->i_lock); |
762 | continue; |
763 | } |
764 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
765 | __wait_on_freeing_inode(inode); |
766 | goto repeat; |
767 | } |
768 | __iget(inode); |
769 | spin_unlock(&inode->i_lock); |
770 | return inode; |
771 | } |
772 | return NULL; |
773 | } |
774 | |
775 | /* |
776 | * find_inode_fast is the fast path version of find_inode, see the comment at |
777 | * iget_locked for details. |
778 | */ |
779 | static struct inode *find_inode_fast(struct super_block *sb, |
780 | struct hlist_head *head, unsigned long ino) |
781 | { |
782 | struct hlist_node *node; |
783 | struct inode *inode = NULL; |
784 | |
785 | repeat: |
786 | hlist_for_each_entry(inode, node, head, i_hash) { |
787 | spin_lock(&inode->i_lock); |
788 | if (inode->i_ino != ino) { |
789 | spin_unlock(&inode->i_lock); |
790 | continue; |
791 | } |
792 | if (inode->i_sb != sb) { |
793 | spin_unlock(&inode->i_lock); |
794 | continue; |
795 | } |
796 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
797 | __wait_on_freeing_inode(inode); |
798 | goto repeat; |
799 | } |
800 | __iget(inode); |
801 | spin_unlock(&inode->i_lock); |
802 | return inode; |
803 | } |
804 | return NULL; |
805 | } |
806 | |
807 | /* |
808 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
809 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
810 | * to renew the exhausted range. |
811 | * |
812 | * This does not significantly increase overflow rate because every CPU can |
813 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
814 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
815 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
816 | * overflow rate by 2x, which does not seem too significant. |
817 | * |
818 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
819 | * error if st_ino won't fit in target struct field. Use 32bit counter |
820 | * here to attempt to avoid that. |
821 | */ |
822 | #define LAST_INO_BATCH 1024 |
823 | static DEFINE_PER_CPU(unsigned int, last_ino); |
824 | |
825 | unsigned int get_next_ino(void) |
826 | { |
827 | unsigned int *p = &get_cpu_var(last_ino); |
828 | unsigned int res = *p; |
829 | |
830 | #ifdef CONFIG_SMP |
831 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
832 | static atomic_t shared_last_ino; |
833 | int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
834 | |
835 | res = next - LAST_INO_BATCH; |
836 | } |
837 | #endif |
838 | |
839 | *p = ++res; |
840 | put_cpu_var(last_ino); |
841 | return res; |
842 | } |
843 | EXPORT_SYMBOL(get_next_ino); |
844 | |
845 | /** |
846 | * new_inode - obtain an inode |
847 | * @sb: superblock |
848 | * |
849 | * Allocates a new inode for given superblock. The default gfp_mask |
850 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
851 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
852 | * for the page cache are not reclaimable or migratable, |
853 | * mapping_set_gfp_mask() must be called with suitable flags on the |
854 | * newly created inode's mapping |
855 | * |
856 | */ |
857 | struct inode *new_inode(struct super_block *sb) |
858 | { |
859 | struct inode *inode; |
860 | |
861 | spin_lock_prefetch(&inode_sb_list_lock); |
862 | |
863 | inode = alloc_inode(sb); |
864 | if (inode) { |
865 | spin_lock(&inode->i_lock); |
866 | inode->i_state = 0; |
867 | spin_unlock(&inode->i_lock); |
868 | inode_sb_list_add(inode); |
869 | } |
870 | return inode; |
871 | } |
872 | EXPORT_SYMBOL(new_inode); |
873 | |
874 | /** |
875 | * unlock_new_inode - clear the I_NEW state and wake up any waiters |
876 | * @inode: new inode to unlock |
877 | * |
878 | * Called when the inode is fully initialised to clear the new state of the |
879 | * inode and wake up anyone waiting for the inode to finish initialisation. |
880 | */ |
881 | void unlock_new_inode(struct inode *inode) |
882 | { |
883 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
884 | if (S_ISDIR(inode->i_mode)) { |
885 | struct file_system_type *type = inode->i_sb->s_type; |
886 | |
887 | /* Set new key only if filesystem hasn't already changed it */ |
888 | if (!lockdep_match_class(&inode->i_mutex, |
889 | &type->i_mutex_key)) { |
890 | /* |
891 | * ensure nobody is actually holding i_mutex |
892 | */ |
893 | mutex_destroy(&inode->i_mutex); |
894 | mutex_init(&inode->i_mutex); |
895 | lockdep_set_class(&inode->i_mutex, |
896 | &type->i_mutex_dir_key); |
897 | } |
898 | } |
899 | #endif |
900 | spin_lock(&inode->i_lock); |
901 | WARN_ON(!(inode->i_state & I_NEW)); |
902 | inode->i_state &= ~I_NEW; |
903 | wake_up_bit(&inode->i_state, __I_NEW); |
904 | spin_unlock(&inode->i_lock); |
905 | } |
906 | EXPORT_SYMBOL(unlock_new_inode); |
907 | |
908 | /** |
909 | * iget5_locked - obtain an inode from a mounted file system |
910 | * @sb: super block of file system |
911 | * @hashval: hash value (usually inode number) to get |
912 | * @test: callback used for comparisons between inodes |
913 | * @set: callback used to initialize a new struct inode |
914 | * @data: opaque data pointer to pass to @test and @set |
915 | * |
916 | * Search for the inode specified by @hashval and @data in the inode cache, |
917 | * and if present it is return it with an increased reference count. This is |
918 | * a generalized version of iget_locked() for file systems where the inode |
919 | * number is not sufficient for unique identification of an inode. |
920 | * |
921 | * If the inode is not in cache, allocate a new inode and return it locked, |
922 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
923 | * before unlocking it via unlock_new_inode(). |
924 | * |
925 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
926 | * sleep. |
927 | */ |
928 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
929 | int (*test)(struct inode *, void *), |
930 | int (*set)(struct inode *, void *), void *data) |
931 | { |
932 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
933 | struct inode *inode; |
934 | |
935 | spin_lock(&inode_hash_lock); |
936 | inode = find_inode(sb, head, test, data); |
937 | spin_unlock(&inode_hash_lock); |
938 | |
939 | if (inode) { |
940 | wait_on_inode(inode); |
941 | return inode; |
942 | } |
943 | |
944 | inode = alloc_inode(sb); |
945 | if (inode) { |
946 | struct inode *old; |
947 | |
948 | spin_lock(&inode_hash_lock); |
949 | /* We released the lock, so.. */ |
950 | old = find_inode(sb, head, test, data); |
951 | if (!old) { |
952 | if (set(inode, data)) |
953 | goto set_failed; |
954 | |
955 | spin_lock(&inode->i_lock); |
956 | inode->i_state = I_NEW; |
957 | hlist_add_head(&inode->i_hash, head); |
958 | spin_unlock(&inode->i_lock); |
959 | inode_sb_list_add(inode); |
960 | spin_unlock(&inode_hash_lock); |
961 | |
962 | /* Return the locked inode with I_NEW set, the |
963 | * caller is responsible for filling in the contents |
964 | */ |
965 | return inode; |
966 | } |
967 | |
968 | /* |
969 | * Uhhuh, somebody else created the same inode under |
970 | * us. Use the old inode instead of the one we just |
971 | * allocated. |
972 | */ |
973 | spin_unlock(&inode_hash_lock); |
974 | destroy_inode(inode); |
975 | inode = old; |
976 | wait_on_inode(inode); |
977 | } |
978 | return inode; |
979 | |
980 | set_failed: |
981 | spin_unlock(&inode_hash_lock); |
982 | destroy_inode(inode); |
983 | return NULL; |
984 | } |
985 | EXPORT_SYMBOL(iget5_locked); |
986 | |
987 | /** |
988 | * iget_locked - obtain an inode from a mounted file system |
989 | * @sb: super block of file system |
990 | * @ino: inode number to get |
991 | * |
992 | * Search for the inode specified by @ino in the inode cache and if present |
993 | * return it with an increased reference count. This is for file systems |
994 | * where the inode number is sufficient for unique identification of an inode. |
995 | * |
996 | * If the inode is not in cache, allocate a new inode and return it locked, |
997 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
998 | * before unlocking it via unlock_new_inode(). |
999 | */ |
1000 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1001 | { |
1002 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1003 | struct inode *inode; |
1004 | |
1005 | spin_lock(&inode_hash_lock); |
1006 | inode = find_inode_fast(sb, head, ino); |
1007 | spin_unlock(&inode_hash_lock); |
1008 | if (inode) { |
1009 | wait_on_inode(inode); |
1010 | return inode; |
1011 | } |
1012 | |
1013 | inode = alloc_inode(sb); |
1014 | if (inode) { |
1015 | struct inode *old; |
1016 | |
1017 | spin_lock(&inode_hash_lock); |
1018 | /* We released the lock, so.. */ |
1019 | old = find_inode_fast(sb, head, ino); |
1020 | if (!old) { |
1021 | inode->i_ino = ino; |
1022 | spin_lock(&inode->i_lock); |
1023 | inode->i_state = I_NEW; |
1024 | hlist_add_head(&inode->i_hash, head); |
1025 | spin_unlock(&inode->i_lock); |
1026 | inode_sb_list_add(inode); |
1027 | spin_unlock(&inode_hash_lock); |
1028 | |
1029 | /* Return the locked inode with I_NEW set, the |
1030 | * caller is responsible for filling in the contents |
1031 | */ |
1032 | return inode; |
1033 | } |
1034 | |
1035 | /* |
1036 | * Uhhuh, somebody else created the same inode under |
1037 | * us. Use the old inode instead of the one we just |
1038 | * allocated. |
1039 | */ |
1040 | spin_unlock(&inode_hash_lock); |
1041 | destroy_inode(inode); |
1042 | inode = old; |
1043 | wait_on_inode(inode); |
1044 | } |
1045 | return inode; |
1046 | } |
1047 | EXPORT_SYMBOL(iget_locked); |
1048 | |
1049 | /* |
1050 | * search the inode cache for a matching inode number. |
1051 | * If we find one, then the inode number we are trying to |
1052 | * allocate is not unique and so we should not use it. |
1053 | * |
1054 | * Returns 1 if the inode number is unique, 0 if it is not. |
1055 | */ |
1056 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
1057 | { |
1058 | struct hlist_head *b = inode_hashtable + hash(sb, ino); |
1059 | struct hlist_node *node; |
1060 | struct inode *inode; |
1061 | |
1062 | spin_lock(&inode_hash_lock); |
1063 | hlist_for_each_entry(inode, node, b, i_hash) { |
1064 | if (inode->i_ino == ino && inode->i_sb == sb) { |
1065 | spin_unlock(&inode_hash_lock); |
1066 | return 0; |
1067 | } |
1068 | } |
1069 | spin_unlock(&inode_hash_lock); |
1070 | |
1071 | return 1; |
1072 | } |
1073 | |
1074 | /** |
1075 | * iunique - get a unique inode number |
1076 | * @sb: superblock |
1077 | * @max_reserved: highest reserved inode number |
1078 | * |
1079 | * Obtain an inode number that is unique on the system for a given |
1080 | * superblock. This is used by file systems that have no natural |
1081 | * permanent inode numbering system. An inode number is returned that |
1082 | * is higher than the reserved limit but unique. |
1083 | * |
1084 | * BUGS: |
1085 | * With a large number of inodes live on the file system this function |
1086 | * currently becomes quite slow. |
1087 | */ |
1088 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
1089 | { |
1090 | /* |
1091 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
1092 | * error if st_ino won't fit in target struct field. Use 32bit counter |
1093 | * here to attempt to avoid that. |
1094 | */ |
1095 | static DEFINE_SPINLOCK(iunique_lock); |
1096 | static unsigned int counter; |
1097 | ino_t res; |
1098 | |
1099 | spin_lock(&iunique_lock); |
1100 | do { |
1101 | if (counter <= max_reserved) |
1102 | counter = max_reserved + 1; |
1103 | res = counter++; |
1104 | } while (!test_inode_iunique(sb, res)); |
1105 | spin_unlock(&iunique_lock); |
1106 | |
1107 | return res; |
1108 | } |
1109 | EXPORT_SYMBOL(iunique); |
1110 | |
1111 | struct inode *igrab(struct inode *inode) |
1112 | { |
1113 | spin_lock(&inode->i_lock); |
1114 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
1115 | __iget(inode); |
1116 | spin_unlock(&inode->i_lock); |
1117 | } else { |
1118 | spin_unlock(&inode->i_lock); |
1119 | /* |
1120 | * Handle the case where s_op->clear_inode is not been |
1121 | * called yet, and somebody is calling igrab |
1122 | * while the inode is getting freed. |
1123 | */ |
1124 | inode = NULL; |
1125 | } |
1126 | return inode; |
1127 | } |
1128 | EXPORT_SYMBOL(igrab); |
1129 | |
1130 | /** |
1131 | * ilookup5_nowait - search for an inode in the inode cache |
1132 | * @sb: super block of file system to search |
1133 | * @hashval: hash value (usually inode number) to search for |
1134 | * @test: callback used for comparisons between inodes |
1135 | * @data: opaque data pointer to pass to @test |
1136 | * |
1137 | * Search for the inode specified by @hashval and @data in the inode cache. |
1138 | * If the inode is in the cache, the inode is returned with an incremented |
1139 | * reference count. |
1140 | * |
1141 | * Note: I_NEW is not waited upon so you have to be very careful what you do |
1142 | * with the returned inode. You probably should be using ilookup5() instead. |
1143 | * |
1144 | * Note2: @test is called with the inode_hash_lock held, so can't sleep. |
1145 | */ |
1146 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
1147 | int (*test)(struct inode *, void *), void *data) |
1148 | { |
1149 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1150 | struct inode *inode; |
1151 | |
1152 | spin_lock(&inode_hash_lock); |
1153 | inode = find_inode(sb, head, test, data); |
1154 | spin_unlock(&inode_hash_lock); |
1155 | |
1156 | return inode; |
1157 | } |
1158 | EXPORT_SYMBOL(ilookup5_nowait); |
1159 | |
1160 | /** |
1161 | * ilookup5 - search for an inode in the inode cache |
1162 | * @sb: super block of file system to search |
1163 | * @hashval: hash value (usually inode number) to search for |
1164 | * @test: callback used for comparisons between inodes |
1165 | * @data: opaque data pointer to pass to @test |
1166 | * |
1167 | * Search for the inode specified by @hashval and @data in the inode cache, |
1168 | * and if the inode is in the cache, return the inode with an incremented |
1169 | * reference count. Waits on I_NEW before returning the inode. |
1170 | * returned with an incremented reference count. |
1171 | * |
1172 | * This is a generalized version of ilookup() for file systems where the |
1173 | * inode number is not sufficient for unique identification of an inode. |
1174 | * |
1175 | * Note: @test is called with the inode_hash_lock held, so can't sleep. |
1176 | */ |
1177 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
1178 | int (*test)(struct inode *, void *), void *data) |
1179 | { |
1180 | struct inode *inode = ilookup5_nowait(sb, hashval, test, data); |
1181 | |
1182 | if (inode) |
1183 | wait_on_inode(inode); |
1184 | return inode; |
1185 | } |
1186 | EXPORT_SYMBOL(ilookup5); |
1187 | |
1188 | /** |
1189 | * ilookup - search for an inode in the inode cache |
1190 | * @sb: super block of file system to search |
1191 | * @ino: inode number to search for |
1192 | * |
1193 | * Search for the inode @ino in the inode cache, and if the inode is in the |
1194 | * cache, the inode is returned with an incremented reference count. |
1195 | */ |
1196 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1197 | { |
1198 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1199 | struct inode *inode; |
1200 | |
1201 | spin_lock(&inode_hash_lock); |
1202 | inode = find_inode_fast(sb, head, ino); |
1203 | spin_unlock(&inode_hash_lock); |
1204 | |
1205 | if (inode) |
1206 | wait_on_inode(inode); |
1207 | return inode; |
1208 | } |
1209 | EXPORT_SYMBOL(ilookup); |
1210 | |
1211 | int insert_inode_locked(struct inode *inode) |
1212 | { |
1213 | struct super_block *sb = inode->i_sb; |
1214 | ino_t ino = inode->i_ino; |
1215 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1216 | |
1217 | while (1) { |
1218 | struct hlist_node *node; |
1219 | struct inode *old = NULL; |
1220 | spin_lock(&inode_hash_lock); |
1221 | hlist_for_each_entry(old, node, head, i_hash) { |
1222 | if (old->i_ino != ino) |
1223 | continue; |
1224 | if (old->i_sb != sb) |
1225 | continue; |
1226 | spin_lock(&old->i_lock); |
1227 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1228 | spin_unlock(&old->i_lock); |
1229 | continue; |
1230 | } |
1231 | break; |
1232 | } |
1233 | if (likely(!node)) { |
1234 | spin_lock(&inode->i_lock); |
1235 | inode->i_state |= I_NEW; |
1236 | hlist_add_head(&inode->i_hash, head); |
1237 | spin_unlock(&inode->i_lock); |
1238 | spin_unlock(&inode_hash_lock); |
1239 | return 0; |
1240 | } |
1241 | __iget(old); |
1242 | spin_unlock(&old->i_lock); |
1243 | spin_unlock(&inode_hash_lock); |
1244 | wait_on_inode(old); |
1245 | if (unlikely(!inode_unhashed(old))) { |
1246 | iput(old); |
1247 | return -EBUSY; |
1248 | } |
1249 | iput(old); |
1250 | } |
1251 | } |
1252 | EXPORT_SYMBOL(insert_inode_locked); |
1253 | |
1254 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1255 | int (*test)(struct inode *, void *), void *data) |
1256 | { |
1257 | struct super_block *sb = inode->i_sb; |
1258 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1259 | |
1260 | while (1) { |
1261 | struct hlist_node *node; |
1262 | struct inode *old = NULL; |
1263 | |
1264 | spin_lock(&inode_hash_lock); |
1265 | hlist_for_each_entry(old, node, head, i_hash) { |
1266 | if (old->i_sb != sb) |
1267 | continue; |
1268 | if (!test(old, data)) |
1269 | continue; |
1270 | spin_lock(&old->i_lock); |
1271 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1272 | spin_unlock(&old->i_lock); |
1273 | continue; |
1274 | } |
1275 | break; |
1276 | } |
1277 | if (likely(!node)) { |
1278 | spin_lock(&inode->i_lock); |
1279 | inode->i_state |= I_NEW; |
1280 | hlist_add_head(&inode->i_hash, head); |
1281 | spin_unlock(&inode->i_lock); |
1282 | spin_unlock(&inode_hash_lock); |
1283 | return 0; |
1284 | } |
1285 | __iget(old); |
1286 | spin_unlock(&old->i_lock); |
1287 | spin_unlock(&inode_hash_lock); |
1288 | wait_on_inode(old); |
1289 | if (unlikely(!inode_unhashed(old))) { |
1290 | iput(old); |
1291 | return -EBUSY; |
1292 | } |
1293 | iput(old); |
1294 | } |
1295 | } |
1296 | EXPORT_SYMBOL(insert_inode_locked4); |
1297 | |
1298 | |
1299 | int generic_delete_inode(struct inode *inode) |
1300 | { |
1301 | return 1; |
1302 | } |
1303 | EXPORT_SYMBOL(generic_delete_inode); |
1304 | |
1305 | /* |
1306 | * Normal UNIX filesystem behaviour: delete the |
1307 | * inode when the usage count drops to zero, and |
1308 | * i_nlink is zero. |
1309 | */ |
1310 | int generic_drop_inode(struct inode *inode) |
1311 | { |
1312 | return !inode->i_nlink || inode_unhashed(inode); |
1313 | } |
1314 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1315 | |
1316 | /* |
1317 | * Called when we're dropping the last reference |
1318 | * to an inode. |
1319 | * |
1320 | * Call the FS "drop_inode()" function, defaulting to |
1321 | * the legacy UNIX filesystem behaviour. If it tells |
1322 | * us to evict inode, do so. Otherwise, retain inode |
1323 | * in cache if fs is alive, sync and evict if fs is |
1324 | * shutting down. |
1325 | */ |
1326 | static void iput_final(struct inode *inode) |
1327 | { |
1328 | struct super_block *sb = inode->i_sb; |
1329 | const struct super_operations *op = inode->i_sb->s_op; |
1330 | int drop; |
1331 | |
1332 | WARN_ON(inode->i_state & I_NEW); |
1333 | |
1334 | if (op && op->drop_inode) |
1335 | drop = op->drop_inode(inode); |
1336 | else |
1337 | drop = generic_drop_inode(inode); |
1338 | |
1339 | if (!drop && (sb->s_flags & MS_ACTIVE)) { |
1340 | inode->i_state |= I_REFERENCED; |
1341 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1342 | inode_lru_list_add(inode); |
1343 | spin_unlock(&inode->i_lock); |
1344 | return; |
1345 | } |
1346 | |
1347 | if (!drop) { |
1348 | inode->i_state |= I_WILL_FREE; |
1349 | spin_unlock(&inode->i_lock); |
1350 | write_inode_now(inode, 1); |
1351 | spin_lock(&inode->i_lock); |
1352 | WARN_ON(inode->i_state & I_NEW); |
1353 | inode->i_state &= ~I_WILL_FREE; |
1354 | } |
1355 | |
1356 | inode->i_state |= I_FREEING; |
1357 | inode_lru_list_del(inode); |
1358 | spin_unlock(&inode->i_lock); |
1359 | |
1360 | evict(inode); |
1361 | } |
1362 | |
1363 | /** |
1364 | * iput - put an inode |
1365 | * @inode: inode to put |
1366 | * |
1367 | * Puts an inode, dropping its usage count. If the inode use count hits |
1368 | * zero, the inode is then freed and may also be destroyed. |
1369 | * |
1370 | * Consequently, iput() can sleep. |
1371 | */ |
1372 | void iput(struct inode *inode) |
1373 | { |
1374 | if (inode) { |
1375 | BUG_ON(inode->i_state & I_CLEAR); |
1376 | |
1377 | if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) |
1378 | iput_final(inode); |
1379 | } |
1380 | } |
1381 | EXPORT_SYMBOL(iput); |
1382 | |
1383 | /** |
1384 | * bmap - find a block number in a file |
1385 | * @inode: inode of file |
1386 | * @block: block to find |
1387 | * |
1388 | * Returns the block number on the device holding the inode that |
1389 | * is the disk block number for the block of the file requested. |
1390 | * That is, asked for block 4 of inode 1 the function will return the |
1391 | * disk block relative to the disk start that holds that block of the |
1392 | * file. |
1393 | */ |
1394 | sector_t bmap(struct inode *inode, sector_t block) |
1395 | { |
1396 | sector_t res = 0; |
1397 | if (inode->i_mapping->a_ops->bmap) |
1398 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
1399 | return res; |
1400 | } |
1401 | EXPORT_SYMBOL(bmap); |
1402 | |
1403 | /* |
1404 | * With relative atime, only update atime if the previous atime is |
1405 | * earlier than either the ctime or mtime or if at least a day has |
1406 | * passed since the last atime update. |
1407 | */ |
1408 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1409 | struct timespec now) |
1410 | { |
1411 | |
1412 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1413 | return 1; |
1414 | /* |
1415 | * Is mtime younger than atime? If yes, update atime: |
1416 | */ |
1417 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
1418 | return 1; |
1419 | /* |
1420 | * Is ctime younger than atime? If yes, update atime: |
1421 | */ |
1422 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
1423 | return 1; |
1424 | |
1425 | /* |
1426 | * Is the previous atime value older than a day? If yes, |
1427 | * update atime: |
1428 | */ |
1429 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
1430 | return 1; |
1431 | /* |
1432 | * Good, we can skip the atime update: |
1433 | */ |
1434 | return 0; |
1435 | } |
1436 | |
1437 | /** |
1438 | * touch_atime - update the access time |
1439 | * @mnt: mount the inode is accessed on |
1440 | * @dentry: dentry accessed |
1441 | * |
1442 | * Update the accessed time on an inode and mark it for writeback. |
1443 | * This function automatically handles read only file systems and media, |
1444 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1445 | */ |
1446 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1447 | { |
1448 | struct inode *inode = dentry->d_inode; |
1449 | struct timespec now; |
1450 | |
1451 | if (inode->i_flags & S_NOATIME) |
1452 | return; |
1453 | if (IS_NOATIME(inode)) |
1454 | return; |
1455 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1456 | return; |
1457 | |
1458 | if (mnt->mnt_flags & MNT_NOATIME) |
1459 | return; |
1460 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1461 | return; |
1462 | |
1463 | now = current_fs_time(inode->i_sb); |
1464 | |
1465 | if (!relatime_need_update(mnt, inode, now)) |
1466 | return; |
1467 | |
1468 | if (timespec_equal(&inode->i_atime, &now)) |
1469 | return; |
1470 | |
1471 | if (mnt_want_write(mnt)) |
1472 | return; |
1473 | |
1474 | inode->i_atime = now; |
1475 | mark_inode_dirty_sync(inode); |
1476 | mnt_drop_write(mnt); |
1477 | } |
1478 | EXPORT_SYMBOL(touch_atime); |
1479 | |
1480 | /** |
1481 | * file_update_time - update mtime and ctime time |
1482 | * @file: file accessed |
1483 | * |
1484 | * Update the mtime and ctime members of an inode and mark the inode |
1485 | * for writeback. Note that this function is meant exclusively for |
1486 | * usage in the file write path of filesystems, and filesystems may |
1487 | * choose to explicitly ignore update via this function with the |
1488 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
1489 | * timestamps are handled by the server. |
1490 | */ |
1491 | |
1492 | void file_update_time(struct file *file) |
1493 | { |
1494 | struct inode *inode = file->f_path.dentry->d_inode; |
1495 | struct timespec now; |
1496 | enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0; |
1497 | |
1498 | /* First try to exhaust all avenues to not sync */ |
1499 | if (IS_NOCMTIME(inode)) |
1500 | return; |
1501 | |
1502 | now = current_fs_time(inode->i_sb); |
1503 | if (!timespec_equal(&inode->i_mtime, &now)) |
1504 | sync_it = S_MTIME; |
1505 | |
1506 | if (!timespec_equal(&inode->i_ctime, &now)) |
1507 | sync_it |= S_CTIME; |
1508 | |
1509 | if (IS_I_VERSION(inode)) |
1510 | sync_it |= S_VERSION; |
1511 | |
1512 | if (!sync_it) |
1513 | return; |
1514 | |
1515 | /* Finally allowed to write? Takes lock. */ |
1516 | if (mnt_want_write_file(file)) |
1517 | return; |
1518 | |
1519 | /* Only change inode inside the lock region */ |
1520 | if (sync_it & S_VERSION) |
1521 | inode_inc_iversion(inode); |
1522 | if (sync_it & S_CTIME) |
1523 | inode->i_ctime = now; |
1524 | if (sync_it & S_MTIME) |
1525 | inode->i_mtime = now; |
1526 | mark_inode_dirty_sync(inode); |
1527 | mnt_drop_write(file->f_path.mnt); |
1528 | } |
1529 | EXPORT_SYMBOL(file_update_time); |
1530 | |
1531 | int inode_needs_sync(struct inode *inode) |
1532 | { |
1533 | if (IS_SYNC(inode)) |
1534 | return 1; |
1535 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
1536 | return 1; |
1537 | return 0; |
1538 | } |
1539 | EXPORT_SYMBOL(inode_needs_sync); |
1540 | |
1541 | int inode_wait(void *word) |
1542 | { |
1543 | schedule(); |
1544 | return 0; |
1545 | } |
1546 | EXPORT_SYMBOL(inode_wait); |
1547 | |
1548 | /* |
1549 | * If we try to find an inode in the inode hash while it is being |
1550 | * deleted, we have to wait until the filesystem completes its |
1551 | * deletion before reporting that it isn't found. This function waits |
1552 | * until the deletion _might_ have completed. Callers are responsible |
1553 | * to recheck inode state. |
1554 | * |
1555 | * It doesn't matter if I_NEW is not set initially, a call to |
1556 | * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
1557 | * will DTRT. |
1558 | */ |
1559 | static void __wait_on_freeing_inode(struct inode *inode) |
1560 | { |
1561 | wait_queue_head_t *wq; |
1562 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
1563 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
1564 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
1565 | spin_unlock(&inode->i_lock); |
1566 | spin_unlock(&inode_hash_lock); |
1567 | schedule(); |
1568 | finish_wait(wq, &wait.wait); |
1569 | spin_lock(&inode_hash_lock); |
1570 | } |
1571 | |
1572 | static __initdata unsigned long ihash_entries; |
1573 | static int __init set_ihash_entries(char *str) |
1574 | { |
1575 | if (!str) |
1576 | return 0; |
1577 | ihash_entries = simple_strtoul(str, &str, 0); |
1578 | return 1; |
1579 | } |
1580 | __setup("ihash_entries=", set_ihash_entries); |
1581 | |
1582 | /* |
1583 | * Initialize the waitqueues and inode hash table. |
1584 | */ |
1585 | void __init inode_init_early(void) |
1586 | { |
1587 | int loop; |
1588 | |
1589 | /* If hashes are distributed across NUMA nodes, defer |
1590 | * hash allocation until vmalloc space is available. |
1591 | */ |
1592 | if (hashdist) |
1593 | return; |
1594 | |
1595 | inode_hashtable = |
1596 | alloc_large_system_hash("Inode-cache", |
1597 | sizeof(struct hlist_head), |
1598 | ihash_entries, |
1599 | 14, |
1600 | HASH_EARLY, |
1601 | &i_hash_shift, |
1602 | &i_hash_mask, |
1603 | 0); |
1604 | |
1605 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1606 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1607 | } |
1608 | |
1609 | void __init inode_init(void) |
1610 | { |
1611 | int loop; |
1612 | |
1613 | /* inode slab cache */ |
1614 | inode_cachep = kmem_cache_create("inode_cache", |
1615 | sizeof(struct inode), |
1616 | 0, |
1617 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
1618 | SLAB_MEM_SPREAD), |
1619 | init_once); |
1620 | register_shrinker(&icache_shrinker); |
1621 | |
1622 | /* Hash may have been set up in inode_init_early */ |
1623 | if (!hashdist) |
1624 | return; |
1625 | |
1626 | inode_hashtable = |
1627 | alloc_large_system_hash("Inode-cache", |
1628 | sizeof(struct hlist_head), |
1629 | ihash_entries, |
1630 | 14, |
1631 | 0, |
1632 | &i_hash_shift, |
1633 | &i_hash_mask, |
1634 | 0); |
1635 | |
1636 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1637 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1638 | } |
1639 | |
1640 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
1641 | { |
1642 | inode->i_mode = mode; |
1643 | if (S_ISCHR(mode)) { |
1644 | inode->i_fop = &def_chr_fops; |
1645 | inode->i_rdev = rdev; |
1646 | } else if (S_ISBLK(mode)) { |
1647 | inode->i_fop = &def_blk_fops; |
1648 | inode->i_rdev = rdev; |
1649 | } else if (S_ISFIFO(mode)) |
1650 | inode->i_fop = &def_fifo_fops; |
1651 | else if (S_ISSOCK(mode)) |
1652 | inode->i_fop = &bad_sock_fops; |
1653 | else |
1654 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
1655 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
1656 | inode->i_ino); |
1657 | } |
1658 | EXPORT_SYMBOL(init_special_inode); |
1659 | |
1660 | /** |
1661 | * inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
1662 | * @inode: New inode |
1663 | * @dir: Directory inode |
1664 | * @mode: mode of the new inode |
1665 | */ |
1666 | void inode_init_owner(struct inode *inode, const struct inode *dir, |
1667 | mode_t mode) |
1668 | { |
1669 | inode->i_uid = current_fsuid(); |
1670 | if (dir && dir->i_mode & S_ISGID) { |
1671 | inode->i_gid = dir->i_gid; |
1672 | if (S_ISDIR(mode)) |
1673 | mode |= S_ISGID; |
1674 | } else |
1675 | inode->i_gid = current_fsgid(); |
1676 | inode->i_mode = mode; |
1677 | } |
1678 | EXPORT_SYMBOL(inode_init_owner); |
1679 | |
1680 | /** |
1681 | * inode_owner_or_capable - check current task permissions to inode |
1682 | * @inode: inode being checked |
1683 | * |
1684 | * Return true if current either has CAP_FOWNER to the inode, or |
1685 | * owns the file. |
1686 | */ |
1687 | bool inode_owner_or_capable(const struct inode *inode) |
1688 | { |
1689 | struct user_namespace *ns = inode_userns(inode); |
1690 | |
1691 | if (current_user_ns() == ns && current_fsuid() == inode->i_uid) |
1692 | return true; |
1693 | if (ns_capable(ns, CAP_FOWNER)) |
1694 | return true; |
1695 | return false; |
1696 | } |
1697 | EXPORT_SYMBOL(inode_owner_or_capable); |
1698 |
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