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Source at commit 6c17a31f1fc515425221067cb3ece599c09dbc5d created 12 years 8 months ago. By Werner Almesberger, atusb, atben: moved from spi/ to ieee802154/; renamed atusb to spi_atusb | |
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1 | /* |
2 | * linux/fs/inode.c |
3 | * |
4 | * (C) 1997 Linus Torvalds |
5 | */ |
6 | |
7 | #include <linux/fs.h> |
8 | #include <linux/mm.h> |
9 | #include <linux/dcache.h> |
10 | #include <linux/init.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/writeback.h> |
13 | #include <linux/module.h> |
14 | #include <linux/backing-dev.h> |
15 | #include <linux/wait.h> |
16 | #include <linux/rwsem.h> |
17 | #include <linux/hash.h> |
18 | #include <linux/swap.h> |
19 | #include <linux/security.h> |
20 | #include <linux/pagemap.h> |
21 | #include <linux/cdev.h> |
22 | #include <linux/bootmem.h> |
23 | #include <linux/fsnotify.h> |
24 | #include <linux/mount.h> |
25 | #include <linux/async.h> |
26 | #include <linux/posix_acl.h> |
27 | #include <linux/ima.h> |
28 | |
29 | /* |
30 | * This is needed for the following functions: |
31 | * - inode_has_buffers |
32 | * - invalidate_bdev |
33 | * |
34 | * FIXME: remove all knowledge of the buffer layer from this file |
35 | */ |
36 | #include <linux/buffer_head.h> |
37 | |
38 | /* |
39 | * New inode.c implementation. |
40 | * |
41 | * This implementation has the basic premise of trying |
42 | * to be extremely low-overhead and SMP-safe, yet be |
43 | * simple enough to be "obviously correct". |
44 | * |
45 | * Famous last words. |
46 | */ |
47 | |
48 | /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */ |
49 | |
50 | /* #define INODE_PARANOIA 1 */ |
51 | /* #define INODE_DEBUG 1 */ |
52 | |
53 | /* |
54 | * Inode lookup is no longer as critical as it used to be: |
55 | * most of the lookups are going to be through the dcache. |
56 | */ |
57 | #define I_HASHBITS i_hash_shift |
58 | #define I_HASHMASK i_hash_mask |
59 | |
60 | static unsigned int i_hash_mask __read_mostly; |
61 | static unsigned int i_hash_shift __read_mostly; |
62 | |
63 | /* |
64 | * Each inode can be on two separate lists. One is |
65 | * the hash list of the inode, used for lookups. The |
66 | * other linked list is the "type" list: |
67 | * "in_use" - valid inode, i_count > 0, i_nlink > 0 |
68 | * "dirty" - as "in_use" but also dirty |
69 | * "unused" - valid inode, i_count = 0 |
70 | * |
71 | * A "dirty" list is maintained for each super block, |
72 | * allowing for low-overhead inode sync() operations. |
73 | */ |
74 | |
75 | static LIST_HEAD(inode_lru); |
76 | static struct hlist_head *inode_hashtable __read_mostly; |
77 | |
78 | /* |
79 | * A simple spinlock to protect the list manipulations. |
80 | * |
81 | * NOTE! You also have to own the lock if you change |
82 | * the i_state of an inode while it is in use.. |
83 | */ |
84 | DEFINE_SPINLOCK(inode_lock); |
85 | |
86 | /* |
87 | * iprune_sem provides exclusion between the kswapd or try_to_free_pages |
88 | * icache shrinking path, and the umount path. Without this exclusion, |
89 | * by the time prune_icache calls iput for the inode whose pages it has |
90 | * been invalidating, or by the time it calls clear_inode & destroy_inode |
91 | * from its final dispose_list, the struct super_block they refer to |
92 | * (for inode->i_sb->s_op) may already have been freed and reused. |
93 | * |
94 | * We make this an rwsem because the fastpath is icache shrinking. In |
95 | * some cases a filesystem may be doing a significant amount of work in |
96 | * its inode reclaim code, so this should improve parallelism. |
97 | */ |
98 | static DECLARE_RWSEM(iprune_sem); |
99 | |
100 | /* |
101 | * Statistics gathering.. |
102 | */ |
103 | struct inodes_stat_t inodes_stat; |
104 | |
105 | static DEFINE_PER_CPU(unsigned int, nr_inodes); |
106 | |
107 | static struct kmem_cache *inode_cachep __read_mostly; |
108 | |
109 | static int get_nr_inodes(void) |
110 | { |
111 | int i; |
112 | int sum = 0; |
113 | for_each_possible_cpu(i) |
114 | sum += per_cpu(nr_inodes, i); |
115 | return sum < 0 ? 0 : sum; |
116 | } |
117 | |
118 | static inline int get_nr_inodes_unused(void) |
119 | { |
120 | return inodes_stat.nr_unused; |
121 | } |
122 | |
123 | int get_nr_dirty_inodes(void) |
124 | { |
125 | /* not actually dirty inodes, but a wild approximation */ |
126 | int nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
127 | return nr_dirty > 0 ? nr_dirty : 0; |
128 | } |
129 | |
130 | /* |
131 | * Handle nr_inode sysctl |
132 | */ |
133 | #ifdef CONFIG_SYSCTL |
134 | int proc_nr_inodes(ctl_table *table, int write, |
135 | void __user *buffer, size_t *lenp, loff_t *ppos) |
136 | { |
137 | inodes_stat.nr_inodes = get_nr_inodes(); |
138 | return proc_dointvec(table, write, buffer, lenp, ppos); |
139 | } |
140 | #endif |
141 | |
142 | static void wake_up_inode(struct inode *inode) |
143 | { |
144 | /* |
145 | * Prevent speculative execution through spin_unlock(&inode_lock); |
146 | */ |
147 | smp_mb(); |
148 | wake_up_bit(&inode->i_state, __I_NEW); |
149 | } |
150 | |
151 | /** |
152 | * inode_init_always - perform inode structure intialisation |
153 | * @sb: superblock inode belongs to |
154 | * @inode: inode to initialise |
155 | * |
156 | * These are initializations that need to be done on every inode |
157 | * allocation as the fields are not initialised by slab allocation. |
158 | */ |
159 | int inode_init_always(struct super_block *sb, struct inode *inode) |
160 | { |
161 | static const struct address_space_operations empty_aops; |
162 | static const struct inode_operations empty_iops; |
163 | static const struct file_operations empty_fops; |
164 | struct address_space *const mapping = &inode->i_data; |
165 | |
166 | inode->i_sb = sb; |
167 | inode->i_blkbits = sb->s_blocksize_bits; |
168 | inode->i_flags = 0; |
169 | atomic_set(&inode->i_count, 1); |
170 | inode->i_op = &empty_iops; |
171 | inode->i_fop = &empty_fops; |
172 | inode->i_nlink = 1; |
173 | inode->i_uid = 0; |
174 | inode->i_gid = 0; |
175 | atomic_set(&inode->i_writecount, 0); |
176 | inode->i_size = 0; |
177 | inode->i_blocks = 0; |
178 | inode->i_bytes = 0; |
179 | inode->i_generation = 0; |
180 | #ifdef CONFIG_QUOTA |
181 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
182 | #endif |
183 | inode->i_pipe = NULL; |
184 | inode->i_bdev = NULL; |
185 | inode->i_cdev = NULL; |
186 | inode->i_rdev = 0; |
187 | inode->dirtied_when = 0; |
188 | |
189 | if (security_inode_alloc(inode)) |
190 | goto out; |
191 | spin_lock_init(&inode->i_lock); |
192 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
193 | |
194 | mutex_init(&inode->i_mutex); |
195 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
196 | |
197 | init_rwsem(&inode->i_alloc_sem); |
198 | lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); |
199 | |
200 | mapping->a_ops = &empty_aops; |
201 | mapping->host = inode; |
202 | mapping->flags = 0; |
203 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
204 | mapping->assoc_mapping = NULL; |
205 | mapping->backing_dev_info = &default_backing_dev_info; |
206 | mapping->writeback_index = 0; |
207 | |
208 | /* |
209 | * If the block_device provides a backing_dev_info for client |
210 | * inodes then use that. Otherwise the inode share the bdev's |
211 | * backing_dev_info. |
212 | */ |
213 | if (sb->s_bdev) { |
214 | struct backing_dev_info *bdi; |
215 | |
216 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
217 | mapping->backing_dev_info = bdi; |
218 | } |
219 | inode->i_private = NULL; |
220 | inode->i_mapping = mapping; |
221 | #ifdef CONFIG_FS_POSIX_ACL |
222 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
223 | #endif |
224 | |
225 | #ifdef CONFIG_FSNOTIFY |
226 | inode->i_fsnotify_mask = 0; |
227 | #endif |
228 | |
229 | this_cpu_inc(nr_inodes); |
230 | |
231 | return 0; |
232 | out: |
233 | return -ENOMEM; |
234 | } |
235 | EXPORT_SYMBOL(inode_init_always); |
236 | |
237 | static struct inode *alloc_inode(struct super_block *sb) |
238 | { |
239 | struct inode *inode; |
240 | |
241 | if (sb->s_op->alloc_inode) |
242 | inode = sb->s_op->alloc_inode(sb); |
243 | else |
244 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
245 | |
246 | if (!inode) |
247 | return NULL; |
248 | |
249 | if (unlikely(inode_init_always(sb, inode))) { |
250 | if (inode->i_sb->s_op->destroy_inode) |
251 | inode->i_sb->s_op->destroy_inode(inode); |
252 | else |
253 | kmem_cache_free(inode_cachep, inode); |
254 | return NULL; |
255 | } |
256 | |
257 | return inode; |
258 | } |
259 | |
260 | void free_inode_nonrcu(struct inode *inode) |
261 | { |
262 | kmem_cache_free(inode_cachep, inode); |
263 | } |
264 | EXPORT_SYMBOL(free_inode_nonrcu); |
265 | |
266 | void __destroy_inode(struct inode *inode) |
267 | { |
268 | BUG_ON(inode_has_buffers(inode)); |
269 | security_inode_free(inode); |
270 | fsnotify_inode_delete(inode); |
271 | #ifdef CONFIG_FS_POSIX_ACL |
272 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
273 | posix_acl_release(inode->i_acl); |
274 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
275 | posix_acl_release(inode->i_default_acl); |
276 | #endif |
277 | this_cpu_dec(nr_inodes); |
278 | } |
279 | EXPORT_SYMBOL(__destroy_inode); |
280 | |
281 | static void i_callback(struct rcu_head *head) |
282 | { |
283 | struct inode *inode = container_of(head, struct inode, i_rcu); |
284 | INIT_LIST_HEAD(&inode->i_dentry); |
285 | kmem_cache_free(inode_cachep, inode); |
286 | } |
287 | |
288 | static void destroy_inode(struct inode *inode) |
289 | { |
290 | BUG_ON(!list_empty(&inode->i_lru)); |
291 | __destroy_inode(inode); |
292 | if (inode->i_sb->s_op->destroy_inode) |
293 | inode->i_sb->s_op->destroy_inode(inode); |
294 | else |
295 | call_rcu(&inode->i_rcu, i_callback); |
296 | } |
297 | |
298 | void address_space_init_once(struct address_space *mapping) |
299 | { |
300 | memset(mapping, 0, sizeof(*mapping)); |
301 | INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); |
302 | spin_lock_init(&mapping->tree_lock); |
303 | spin_lock_init(&mapping->i_mmap_lock); |
304 | INIT_LIST_HEAD(&mapping->private_list); |
305 | spin_lock_init(&mapping->private_lock); |
306 | INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap); |
307 | INIT_LIST_HEAD(&mapping->i_mmap_nonlinear); |
308 | mutex_init(&mapping->unmap_mutex); |
309 | } |
310 | EXPORT_SYMBOL(address_space_init_once); |
311 | |
312 | /* |
313 | * These are initializations that only need to be done |
314 | * once, because the fields are idempotent across use |
315 | * of the inode, so let the slab aware of that. |
316 | */ |
317 | void inode_init_once(struct inode *inode) |
318 | { |
319 | memset(inode, 0, sizeof(*inode)); |
320 | INIT_HLIST_NODE(&inode->i_hash); |
321 | INIT_LIST_HEAD(&inode->i_dentry); |
322 | INIT_LIST_HEAD(&inode->i_devices); |
323 | INIT_LIST_HEAD(&inode->i_wb_list); |
324 | INIT_LIST_HEAD(&inode->i_lru); |
325 | address_space_init_once(&inode->i_data); |
326 | i_size_ordered_init(inode); |
327 | #ifdef CONFIG_FSNOTIFY |
328 | INIT_HLIST_HEAD(&inode->i_fsnotify_marks); |
329 | #endif |
330 | } |
331 | EXPORT_SYMBOL(inode_init_once); |
332 | |
333 | static void init_once(void *foo) |
334 | { |
335 | struct inode *inode = (struct inode *) foo; |
336 | |
337 | inode_init_once(inode); |
338 | } |
339 | |
340 | /* |
341 | * inode_lock must be held |
342 | */ |
343 | void __iget(struct inode *inode) |
344 | { |
345 | atomic_inc(&inode->i_count); |
346 | } |
347 | |
348 | /* |
349 | * get additional reference to inode; caller must already hold one. |
350 | */ |
351 | void ihold(struct inode *inode) |
352 | { |
353 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
354 | } |
355 | EXPORT_SYMBOL(ihold); |
356 | |
357 | static void inode_lru_list_add(struct inode *inode) |
358 | { |
359 | if (list_empty(&inode->i_lru)) { |
360 | list_add(&inode->i_lru, &inode_lru); |
361 | inodes_stat.nr_unused++; |
362 | } |
363 | } |
364 | |
365 | static void inode_lru_list_del(struct inode *inode) |
366 | { |
367 | if (!list_empty(&inode->i_lru)) { |
368 | list_del_init(&inode->i_lru); |
369 | inodes_stat.nr_unused--; |
370 | } |
371 | } |
372 | |
373 | static inline void __inode_sb_list_add(struct inode *inode) |
374 | { |
375 | list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
376 | } |
377 | |
378 | /** |
379 | * inode_sb_list_add - add inode to the superblock list of inodes |
380 | * @inode: inode to add |
381 | */ |
382 | void inode_sb_list_add(struct inode *inode) |
383 | { |
384 | spin_lock(&inode_lock); |
385 | __inode_sb_list_add(inode); |
386 | spin_unlock(&inode_lock); |
387 | } |
388 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
389 | |
390 | static inline void __inode_sb_list_del(struct inode *inode) |
391 | { |
392 | list_del_init(&inode->i_sb_list); |
393 | } |
394 | |
395 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
396 | { |
397 | unsigned long tmp; |
398 | |
399 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
400 | L1_CACHE_BYTES; |
401 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); |
402 | return tmp & I_HASHMASK; |
403 | } |
404 | |
405 | /** |
406 | * __insert_inode_hash - hash an inode |
407 | * @inode: unhashed inode |
408 | * @hashval: unsigned long value used to locate this object in the |
409 | * inode_hashtable. |
410 | * |
411 | * Add an inode to the inode hash for this superblock. |
412 | */ |
413 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
414 | { |
415 | struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
416 | |
417 | spin_lock(&inode_lock); |
418 | hlist_add_head(&inode->i_hash, b); |
419 | spin_unlock(&inode_lock); |
420 | } |
421 | EXPORT_SYMBOL(__insert_inode_hash); |
422 | |
423 | /** |
424 | * __remove_inode_hash - remove an inode from the hash |
425 | * @inode: inode to unhash |
426 | * |
427 | * Remove an inode from the superblock. |
428 | */ |
429 | static void __remove_inode_hash(struct inode *inode) |
430 | { |
431 | hlist_del_init(&inode->i_hash); |
432 | } |
433 | |
434 | /** |
435 | * remove_inode_hash - remove an inode from the hash |
436 | * @inode: inode to unhash |
437 | * |
438 | * Remove an inode from the superblock. |
439 | */ |
440 | void remove_inode_hash(struct inode *inode) |
441 | { |
442 | spin_lock(&inode_lock); |
443 | hlist_del_init(&inode->i_hash); |
444 | spin_unlock(&inode_lock); |
445 | } |
446 | EXPORT_SYMBOL(remove_inode_hash); |
447 | |
448 | void end_writeback(struct inode *inode) |
449 | { |
450 | might_sleep(); |
451 | BUG_ON(inode->i_data.nrpages); |
452 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
453 | BUG_ON(!(inode->i_state & I_FREEING)); |
454 | BUG_ON(inode->i_state & I_CLEAR); |
455 | inode_sync_wait(inode); |
456 | /* don't need i_lock here, no concurrent mods to i_state */ |
457 | inode->i_state = I_FREEING | I_CLEAR; |
458 | } |
459 | EXPORT_SYMBOL(end_writeback); |
460 | |
461 | static void evict(struct inode *inode) |
462 | { |
463 | const struct super_operations *op = inode->i_sb->s_op; |
464 | |
465 | if (op->evict_inode) { |
466 | op->evict_inode(inode); |
467 | } else { |
468 | if (inode->i_data.nrpages) |
469 | truncate_inode_pages(&inode->i_data, 0); |
470 | end_writeback(inode); |
471 | } |
472 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
473 | bd_forget(inode); |
474 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
475 | cd_forget(inode); |
476 | } |
477 | |
478 | /* |
479 | * dispose_list - dispose of the contents of a local list |
480 | * @head: the head of the list to free |
481 | * |
482 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
483 | * need to worry about list corruption and SMP locks. |
484 | */ |
485 | static void dispose_list(struct list_head *head) |
486 | { |
487 | while (!list_empty(head)) { |
488 | struct inode *inode; |
489 | |
490 | inode = list_first_entry(head, struct inode, i_lru); |
491 | list_del_init(&inode->i_lru); |
492 | |
493 | evict(inode); |
494 | |
495 | spin_lock(&inode_lock); |
496 | __remove_inode_hash(inode); |
497 | __inode_sb_list_del(inode); |
498 | spin_unlock(&inode_lock); |
499 | |
500 | wake_up_inode(inode); |
501 | destroy_inode(inode); |
502 | } |
503 | } |
504 | |
505 | /** |
506 | * evict_inodes - evict all evictable inodes for a superblock |
507 | * @sb: superblock to operate on |
508 | * |
509 | * Make sure that no inodes with zero refcount are retained. This is |
510 | * called by superblock shutdown after having MS_ACTIVE flag removed, |
511 | * so any inode reaching zero refcount during or after that call will |
512 | * be immediately evicted. |
513 | */ |
514 | void evict_inodes(struct super_block *sb) |
515 | { |
516 | struct inode *inode, *next; |
517 | LIST_HEAD(dispose); |
518 | |
519 | down_write(&iprune_sem); |
520 | |
521 | spin_lock(&inode_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 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
527 | WARN_ON(1); |
528 | continue; |
529 | } |
530 | |
531 | inode->i_state |= I_FREEING; |
532 | |
533 | /* |
534 | * Move the inode off the IO lists and LRU once I_FREEING is |
535 | * set so that it won't get moved back on there if it is dirty. |
536 | */ |
537 | list_move(&inode->i_lru, &dispose); |
538 | list_del_init(&inode->i_wb_list); |
539 | if (!(inode->i_state & (I_DIRTY | I_SYNC))) |
540 | inodes_stat.nr_unused--; |
541 | } |
542 | spin_unlock(&inode_lock); |
543 | |
544 | dispose_list(&dispose); |
545 | up_write(&iprune_sem); |
546 | } |
547 | |
548 | /** |
549 | * invalidate_inodes - attempt to free all inodes on a superblock |
550 | * @sb: superblock to operate on |
551 | * @kill_dirty: flag to guide handling of dirty inodes |
552 | * |
553 | * Attempts to free all inodes for a given superblock. If there were any |
554 | * busy inodes return a non-zero value, else zero. |
555 | * If @kill_dirty is set, discard dirty inodes too, otherwise treat |
556 | * them as busy. |
557 | */ |
558 | int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
559 | { |
560 | int busy = 0; |
561 | struct inode *inode, *next; |
562 | LIST_HEAD(dispose); |
563 | |
564 | down_write(&iprune_sem); |
565 | |
566 | spin_lock(&inode_lock); |
567 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
568 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) |
569 | continue; |
570 | if (inode->i_state & I_DIRTY && !kill_dirty) { |
571 | busy = 1; |
572 | continue; |
573 | } |
574 | if (atomic_read(&inode->i_count)) { |
575 | busy = 1; |
576 | continue; |
577 | } |
578 | |
579 | inode->i_state |= I_FREEING; |
580 | |
581 | /* |
582 | * Move the inode off the IO lists and LRU once I_FREEING is |
583 | * set so that it won't get moved back on there if it is dirty. |
584 | */ |
585 | list_move(&inode->i_lru, &dispose); |
586 | list_del_init(&inode->i_wb_list); |
587 | if (!(inode->i_state & (I_DIRTY | I_SYNC))) |
588 | inodes_stat.nr_unused--; |
589 | } |
590 | spin_unlock(&inode_lock); |
591 | |
592 | dispose_list(&dispose); |
593 | up_write(&iprune_sem); |
594 | |
595 | return busy; |
596 | } |
597 | |
598 | static int can_unuse(struct inode *inode) |
599 | { |
600 | if (inode->i_state & ~I_REFERENCED) |
601 | return 0; |
602 | if (inode_has_buffers(inode)) |
603 | return 0; |
604 | if (atomic_read(&inode->i_count)) |
605 | return 0; |
606 | if (inode->i_data.nrpages) |
607 | return 0; |
608 | return 1; |
609 | } |
610 | |
611 | /* |
612 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to a |
613 | * temporary list and then are freed outside inode_lock by dispose_list(). |
614 | * |
615 | * Any inodes which are pinned purely because of attached pagecache have their |
616 | * pagecache removed. If the inode has metadata buffers attached to |
617 | * mapping->private_list then try to remove them. |
618 | * |
619 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
620 | * used recently - the flag is set in iput_final(). When we encounter such an |
621 | * inode, clear the flag and move it to the back of the LRU so it gets another |
622 | * pass through the LRU before it gets reclaimed. This is necessary because of |
623 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
624 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
625 | * with this flag set because they are the inodes that are out of order. |
626 | */ |
627 | static void prune_icache(int nr_to_scan) |
628 | { |
629 | LIST_HEAD(freeable); |
630 | int nr_scanned; |
631 | unsigned long reap = 0; |
632 | |
633 | down_read(&iprune_sem); |
634 | spin_lock(&inode_lock); |
635 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { |
636 | struct inode *inode; |
637 | |
638 | if (list_empty(&inode_lru)) |
639 | break; |
640 | |
641 | inode = list_entry(inode_lru.prev, struct inode, i_lru); |
642 | |
643 | /* |
644 | * Referenced or dirty inodes are still in use. Give them |
645 | * another pass through the LRU as we canot reclaim them now. |
646 | */ |
647 | if (atomic_read(&inode->i_count) || |
648 | (inode->i_state & ~I_REFERENCED)) { |
649 | list_del_init(&inode->i_lru); |
650 | inodes_stat.nr_unused--; |
651 | continue; |
652 | } |
653 | |
654 | /* recently referenced inodes get one more pass */ |
655 | if (inode->i_state & I_REFERENCED) { |
656 | list_move(&inode->i_lru, &inode_lru); |
657 | inode->i_state &= ~I_REFERENCED; |
658 | continue; |
659 | } |
660 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
661 | __iget(inode); |
662 | spin_unlock(&inode_lock); |
663 | if (remove_inode_buffers(inode)) |
664 | reap += invalidate_mapping_pages(&inode->i_data, |
665 | 0, -1); |
666 | iput(inode); |
667 | spin_lock(&inode_lock); |
668 | |
669 | if (inode != list_entry(inode_lru.next, |
670 | struct inode, i_lru)) |
671 | continue; /* wrong inode or list_empty */ |
672 | if (!can_unuse(inode)) |
673 | continue; |
674 | } |
675 | WARN_ON(inode->i_state & I_NEW); |
676 | inode->i_state |= I_FREEING; |
677 | |
678 | /* |
679 | * Move the inode off the IO lists and LRU once I_FREEING is |
680 | * set so that it won't get moved back on there if it is dirty. |
681 | */ |
682 | list_move(&inode->i_lru, &freeable); |
683 | list_del_init(&inode->i_wb_list); |
684 | inodes_stat.nr_unused--; |
685 | } |
686 | if (current_is_kswapd()) |
687 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
688 | else |
689 | __count_vm_events(PGINODESTEAL, reap); |
690 | spin_unlock(&inode_lock); |
691 | |
692 | dispose_list(&freeable); |
693 | up_read(&iprune_sem); |
694 | } |
695 | |
696 | /* |
697 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, |
698 | * "unused" means that no dentries are referring to the inodes: the files are |
699 | * not open and the dcache references to those inodes have already been |
700 | * reclaimed. |
701 | * |
702 | * This function is passed the number of inodes to scan, and it returns the |
703 | * total number of remaining possibly-reclaimable inodes. |
704 | */ |
705 | static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask) |
706 | { |
707 | if (nr) { |
708 | /* |
709 | * Nasty deadlock avoidance. We may hold various FS locks, |
710 | * and we don't want to recurse into the FS that called us |
711 | * in clear_inode() and friends.. |
712 | */ |
713 | if (!(gfp_mask & __GFP_FS)) |
714 | return -1; |
715 | prune_icache(nr); |
716 | } |
717 | return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure; |
718 | } |
719 | |
720 | static struct shrinker icache_shrinker = { |
721 | .shrink = shrink_icache_memory, |
722 | .seeks = DEFAULT_SEEKS, |
723 | }; |
724 | |
725 | static void __wait_on_freeing_inode(struct inode *inode); |
726 | /* |
727 | * Called with the inode lock held. |
728 | */ |
729 | static struct inode *find_inode(struct super_block *sb, |
730 | struct hlist_head *head, |
731 | int (*test)(struct inode *, void *), |
732 | void *data) |
733 | { |
734 | struct hlist_node *node; |
735 | struct inode *inode = NULL; |
736 | |
737 | repeat: |
738 | hlist_for_each_entry(inode, node, head, i_hash) { |
739 | if (inode->i_sb != sb) |
740 | continue; |
741 | if (!test(inode, data)) |
742 | continue; |
743 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
744 | __wait_on_freeing_inode(inode); |
745 | goto repeat; |
746 | } |
747 | __iget(inode); |
748 | return inode; |
749 | } |
750 | return NULL; |
751 | } |
752 | |
753 | /* |
754 | * find_inode_fast is the fast path version of find_inode, see the comment at |
755 | * iget_locked for details. |
756 | */ |
757 | static struct inode *find_inode_fast(struct super_block *sb, |
758 | struct hlist_head *head, unsigned long ino) |
759 | { |
760 | struct hlist_node *node; |
761 | struct inode *inode = NULL; |
762 | |
763 | repeat: |
764 | hlist_for_each_entry(inode, node, head, i_hash) { |
765 | if (inode->i_ino != ino) |
766 | continue; |
767 | if (inode->i_sb != sb) |
768 | continue; |
769 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
770 | __wait_on_freeing_inode(inode); |
771 | goto repeat; |
772 | } |
773 | __iget(inode); |
774 | return inode; |
775 | } |
776 | return NULL; |
777 | } |
778 | |
779 | /* |
780 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
781 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
782 | * to renew the exhausted range. |
783 | * |
784 | * This does not significantly increase overflow rate because every CPU can |
785 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
786 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
787 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
788 | * overflow rate by 2x, which does not seem too significant. |
789 | * |
790 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
791 | * error if st_ino won't fit in target struct field. Use 32bit counter |
792 | * here to attempt to avoid that. |
793 | */ |
794 | #define LAST_INO_BATCH 1024 |
795 | static DEFINE_PER_CPU(unsigned int, last_ino); |
796 | |
797 | unsigned int get_next_ino(void) |
798 | { |
799 | unsigned int *p = &get_cpu_var(last_ino); |
800 | unsigned int res = *p; |
801 | |
802 | #ifdef CONFIG_SMP |
803 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
804 | static atomic_t shared_last_ino; |
805 | int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
806 | |
807 | res = next - LAST_INO_BATCH; |
808 | } |
809 | #endif |
810 | |
811 | *p = ++res; |
812 | put_cpu_var(last_ino); |
813 | return res; |
814 | } |
815 | EXPORT_SYMBOL(get_next_ino); |
816 | |
817 | /** |
818 | * new_inode - obtain an inode |
819 | * @sb: superblock |
820 | * |
821 | * Allocates a new inode for given superblock. The default gfp_mask |
822 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
823 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
824 | * for the page cache are not reclaimable or migratable, |
825 | * mapping_set_gfp_mask() must be called with suitable flags on the |
826 | * newly created inode's mapping |
827 | * |
828 | */ |
829 | struct inode *new_inode(struct super_block *sb) |
830 | { |
831 | struct inode *inode; |
832 | |
833 | spin_lock_prefetch(&inode_lock); |
834 | |
835 | inode = alloc_inode(sb); |
836 | if (inode) { |
837 | spin_lock(&inode_lock); |
838 | __inode_sb_list_add(inode); |
839 | inode->i_state = 0; |
840 | spin_unlock(&inode_lock); |
841 | } |
842 | return inode; |
843 | } |
844 | EXPORT_SYMBOL(new_inode); |
845 | |
846 | void unlock_new_inode(struct inode *inode) |
847 | { |
848 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
849 | if (S_ISDIR(inode->i_mode)) { |
850 | struct file_system_type *type = inode->i_sb->s_type; |
851 | |
852 | /* Set new key only if filesystem hasn't already changed it */ |
853 | if (!lockdep_match_class(&inode->i_mutex, |
854 | &type->i_mutex_key)) { |
855 | /* |
856 | * ensure nobody is actually holding i_mutex |
857 | */ |
858 | mutex_destroy(&inode->i_mutex); |
859 | mutex_init(&inode->i_mutex); |
860 | lockdep_set_class(&inode->i_mutex, |
861 | &type->i_mutex_dir_key); |
862 | } |
863 | } |
864 | #endif |
865 | /* |
866 | * This is special! We do not need the spinlock when clearing I_NEW, |
867 | * because we're guaranteed that nobody else tries to do anything about |
868 | * the state of the inode when it is locked, as we just created it (so |
869 | * there can be no old holders that haven't tested I_NEW). |
870 | * However we must emit the memory barrier so that other CPUs reliably |
871 | * see the clearing of I_NEW after the other inode initialisation has |
872 | * completed. |
873 | */ |
874 | smp_mb(); |
875 | WARN_ON(!(inode->i_state & I_NEW)); |
876 | inode->i_state &= ~I_NEW; |
877 | wake_up_inode(inode); |
878 | } |
879 | EXPORT_SYMBOL(unlock_new_inode); |
880 | |
881 | /* |
882 | * This is called without the inode lock held.. Be careful. |
883 | * |
884 | * We no longer cache the sb_flags in i_flags - see fs.h |
885 | * -- rmk@arm.uk.linux.org |
886 | */ |
887 | static struct inode *get_new_inode(struct super_block *sb, |
888 | struct hlist_head *head, |
889 | int (*test)(struct inode *, void *), |
890 | int (*set)(struct inode *, void *), |
891 | void *data) |
892 | { |
893 | struct inode *inode; |
894 | |
895 | inode = alloc_inode(sb); |
896 | if (inode) { |
897 | struct inode *old; |
898 | |
899 | spin_lock(&inode_lock); |
900 | /* We released the lock, so.. */ |
901 | old = find_inode(sb, head, test, data); |
902 | if (!old) { |
903 | if (set(inode, data)) |
904 | goto set_failed; |
905 | |
906 | hlist_add_head(&inode->i_hash, head); |
907 | __inode_sb_list_add(inode); |
908 | inode->i_state = I_NEW; |
909 | spin_unlock(&inode_lock); |
910 | |
911 | /* Return the locked inode with I_NEW set, the |
912 | * caller is responsible for filling in the contents |
913 | */ |
914 | return inode; |
915 | } |
916 | |
917 | /* |
918 | * Uhhuh, somebody else created the same inode under |
919 | * us. Use the old inode instead of the one we just |
920 | * allocated. |
921 | */ |
922 | spin_unlock(&inode_lock); |
923 | destroy_inode(inode); |
924 | inode = old; |
925 | wait_on_inode(inode); |
926 | } |
927 | return inode; |
928 | |
929 | set_failed: |
930 | spin_unlock(&inode_lock); |
931 | destroy_inode(inode); |
932 | return NULL; |
933 | } |
934 | |
935 | /* |
936 | * get_new_inode_fast is the fast path version of get_new_inode, see the |
937 | * comment at iget_locked for details. |
938 | */ |
939 | static struct inode *get_new_inode_fast(struct super_block *sb, |
940 | struct hlist_head *head, unsigned long ino) |
941 | { |
942 | struct inode *inode; |
943 | |
944 | inode = alloc_inode(sb); |
945 | if (inode) { |
946 | struct inode *old; |
947 | |
948 | spin_lock(&inode_lock); |
949 | /* We released the lock, so.. */ |
950 | old = find_inode_fast(sb, head, ino); |
951 | if (!old) { |
952 | inode->i_ino = ino; |
953 | hlist_add_head(&inode->i_hash, head); |
954 | __inode_sb_list_add(inode); |
955 | inode->i_state = I_NEW; |
956 | spin_unlock(&inode_lock); |
957 | |
958 | /* Return the locked inode with I_NEW set, the |
959 | * caller is responsible for filling in the contents |
960 | */ |
961 | return inode; |
962 | } |
963 | |
964 | /* |
965 | * Uhhuh, somebody else created the same inode under |
966 | * us. Use the old inode instead of the one we just |
967 | * allocated. |
968 | */ |
969 | spin_unlock(&inode_lock); |
970 | destroy_inode(inode); |
971 | inode = old; |
972 | wait_on_inode(inode); |
973 | } |
974 | return inode; |
975 | } |
976 | |
977 | /* |
978 | * search the inode cache for a matching inode number. |
979 | * If we find one, then the inode number we are trying to |
980 | * allocate is not unique and so we should not use it. |
981 | * |
982 | * Returns 1 if the inode number is unique, 0 if it is not. |
983 | */ |
984 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
985 | { |
986 | struct hlist_head *b = inode_hashtable + hash(sb, ino); |
987 | struct hlist_node *node; |
988 | struct inode *inode; |
989 | |
990 | hlist_for_each_entry(inode, node, b, i_hash) { |
991 | if (inode->i_ino == ino && inode->i_sb == sb) |
992 | return 0; |
993 | } |
994 | |
995 | return 1; |
996 | } |
997 | |
998 | /** |
999 | * iunique - get a unique inode number |
1000 | * @sb: superblock |
1001 | * @max_reserved: highest reserved inode number |
1002 | * |
1003 | * Obtain an inode number that is unique on the system for a given |
1004 | * superblock. This is used by file systems that have no natural |
1005 | * permanent inode numbering system. An inode number is returned that |
1006 | * is higher than the reserved limit but unique. |
1007 | * |
1008 | * BUGS: |
1009 | * With a large number of inodes live on the file system this function |
1010 | * currently becomes quite slow. |
1011 | */ |
1012 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
1013 | { |
1014 | /* |
1015 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
1016 | * error if st_ino won't fit in target struct field. Use 32bit counter |
1017 | * here to attempt to avoid that. |
1018 | */ |
1019 | static DEFINE_SPINLOCK(iunique_lock); |
1020 | static unsigned int counter; |
1021 | ino_t res; |
1022 | |
1023 | spin_lock(&inode_lock); |
1024 | spin_lock(&iunique_lock); |
1025 | do { |
1026 | if (counter <= max_reserved) |
1027 | counter = max_reserved + 1; |
1028 | res = counter++; |
1029 | } while (!test_inode_iunique(sb, res)); |
1030 | spin_unlock(&iunique_lock); |
1031 | spin_unlock(&inode_lock); |
1032 | |
1033 | return res; |
1034 | } |
1035 | EXPORT_SYMBOL(iunique); |
1036 | |
1037 | struct inode *igrab(struct inode *inode) |
1038 | { |
1039 | spin_lock(&inode_lock); |
1040 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) |
1041 | __iget(inode); |
1042 | else |
1043 | /* |
1044 | * Handle the case where s_op->clear_inode is not been |
1045 | * called yet, and somebody is calling igrab |
1046 | * while the inode is getting freed. |
1047 | */ |
1048 | inode = NULL; |
1049 | spin_unlock(&inode_lock); |
1050 | return inode; |
1051 | } |
1052 | EXPORT_SYMBOL(igrab); |
1053 | |
1054 | /** |
1055 | * ifind - internal function, you want ilookup5() or iget5(). |
1056 | * @sb: super block of file system to search |
1057 | * @head: the head of the list to search |
1058 | * @test: callback used for comparisons between inodes |
1059 | * @data: opaque data pointer to pass to @test |
1060 | * @wait: if true wait for the inode to be unlocked, if false do not |
1061 | * |
1062 | * ifind() searches for the inode specified by @data in the inode |
1063 | * cache. This is a generalized version of ifind_fast() for file systems where |
1064 | * the inode number is not sufficient for unique identification of an inode. |
1065 | * |
1066 | * If the inode is in the cache, the inode is returned with an incremented |
1067 | * reference count. |
1068 | * |
1069 | * Otherwise NULL is returned. |
1070 | * |
1071 | * Note, @test is called with the inode_lock held, so can't sleep. |
1072 | */ |
1073 | static struct inode *ifind(struct super_block *sb, |
1074 | struct hlist_head *head, int (*test)(struct inode *, void *), |
1075 | void *data, const int wait) |
1076 | { |
1077 | struct inode *inode; |
1078 | |
1079 | spin_lock(&inode_lock); |
1080 | inode = find_inode(sb, head, test, data); |
1081 | if (inode) { |
1082 | spin_unlock(&inode_lock); |
1083 | if (likely(wait)) |
1084 | wait_on_inode(inode); |
1085 | return inode; |
1086 | } |
1087 | spin_unlock(&inode_lock); |
1088 | return NULL; |
1089 | } |
1090 | |
1091 | /** |
1092 | * ifind_fast - internal function, you want ilookup() or iget(). |
1093 | * @sb: super block of file system to search |
1094 | * @head: head of the list to search |
1095 | * @ino: inode number to search for |
1096 | * |
1097 | * ifind_fast() searches for the inode @ino in the inode cache. This is for |
1098 | * file systems where the inode number is sufficient for unique identification |
1099 | * of an inode. |
1100 | * |
1101 | * If the inode is in the cache, the inode is returned with an incremented |
1102 | * reference count. |
1103 | * |
1104 | * Otherwise NULL is returned. |
1105 | */ |
1106 | static struct inode *ifind_fast(struct super_block *sb, |
1107 | struct hlist_head *head, unsigned long ino) |
1108 | { |
1109 | struct inode *inode; |
1110 | |
1111 | spin_lock(&inode_lock); |
1112 | inode = find_inode_fast(sb, head, ino); |
1113 | if (inode) { |
1114 | spin_unlock(&inode_lock); |
1115 | wait_on_inode(inode); |
1116 | return inode; |
1117 | } |
1118 | spin_unlock(&inode_lock); |
1119 | return NULL; |
1120 | } |
1121 | |
1122 | /** |
1123 | * ilookup5_nowait - search for an inode in the inode cache |
1124 | * @sb: super block of file system to search |
1125 | * @hashval: hash value (usually inode number) to search for |
1126 | * @test: callback used for comparisons between inodes |
1127 | * @data: opaque data pointer to pass to @test |
1128 | * |
1129 | * ilookup5() uses ifind() to search for the inode specified by @hashval and |
1130 | * @data in the inode cache. This is a generalized version of ilookup() for |
1131 | * file systems where the inode number is not sufficient for unique |
1132 | * identification of an inode. |
1133 | * |
1134 | * If the inode is in the cache, the inode is returned with an incremented |
1135 | * reference count. Note, the inode lock is not waited upon so you have to be |
1136 | * very careful what you do with the returned inode. You probably should be |
1137 | * using ilookup5() instead. |
1138 | * |
1139 | * Otherwise NULL is returned. |
1140 | * |
1141 | * Note, @test is called with the inode_lock held, so can't sleep. |
1142 | */ |
1143 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
1144 | int (*test)(struct inode *, void *), void *data) |
1145 | { |
1146 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1147 | |
1148 | return ifind(sb, head, test, data, 0); |
1149 | } |
1150 | EXPORT_SYMBOL(ilookup5_nowait); |
1151 | |
1152 | /** |
1153 | * ilookup5 - search for an inode in the inode cache |
1154 | * @sb: super block of file system to search |
1155 | * @hashval: hash value (usually inode number) to search for |
1156 | * @test: callback used for comparisons between inodes |
1157 | * @data: opaque data pointer to pass to @test |
1158 | * |
1159 | * ilookup5() uses ifind() to search for the inode specified by @hashval and |
1160 | * @data in the inode cache. This is a generalized version of ilookup() for |
1161 | * file systems where the inode number is not sufficient for unique |
1162 | * identification of an inode. |
1163 | * |
1164 | * If the inode is in the cache, the inode lock is waited upon and the inode is |
1165 | * returned with an incremented reference count. |
1166 | * |
1167 | * Otherwise NULL is returned. |
1168 | * |
1169 | * Note, @test is called with the inode_lock held, so can't sleep. |
1170 | */ |
1171 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
1172 | int (*test)(struct inode *, void *), void *data) |
1173 | { |
1174 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1175 | |
1176 | return ifind(sb, head, test, data, 1); |
1177 | } |
1178 | EXPORT_SYMBOL(ilookup5); |
1179 | |
1180 | /** |
1181 | * ilookup - search for an inode in the inode cache |
1182 | * @sb: super block of file system to search |
1183 | * @ino: inode number to search for |
1184 | * |
1185 | * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. |
1186 | * This is for file systems where the inode number is sufficient for unique |
1187 | * identification of an inode. |
1188 | * |
1189 | * If the inode is in the cache, the inode is returned with an incremented |
1190 | * reference count. |
1191 | * |
1192 | * Otherwise NULL is returned. |
1193 | */ |
1194 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1195 | { |
1196 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1197 | |
1198 | return ifind_fast(sb, head, ino); |
1199 | } |
1200 | EXPORT_SYMBOL(ilookup); |
1201 | |
1202 | /** |
1203 | * iget5_locked - obtain an inode from a mounted file system |
1204 | * @sb: super block of file system |
1205 | * @hashval: hash value (usually inode number) to get |
1206 | * @test: callback used for comparisons between inodes |
1207 | * @set: callback used to initialize a new struct inode |
1208 | * @data: opaque data pointer to pass to @test and @set |
1209 | * |
1210 | * iget5_locked() uses ifind() to search for the inode specified by @hashval |
1211 | * and @data in the inode cache and if present it is returned with an increased |
1212 | * reference count. This is a generalized version of iget_locked() for file |
1213 | * systems where the inode number is not sufficient for unique identification |
1214 | * of an inode. |
1215 | * |
1216 | * If the inode is not in cache, get_new_inode() is called to allocate a new |
1217 | * inode and this is returned locked, hashed, and with the I_NEW flag set. The |
1218 | * file system gets to fill it in before unlocking it via unlock_new_inode(). |
1219 | * |
1220 | * Note both @test and @set are called with the inode_lock held, so can't sleep. |
1221 | */ |
1222 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
1223 | int (*test)(struct inode *, void *), |
1224 | int (*set)(struct inode *, void *), void *data) |
1225 | { |
1226 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1227 | struct inode *inode; |
1228 | |
1229 | inode = ifind(sb, head, test, data, 1); |
1230 | if (inode) |
1231 | return inode; |
1232 | /* |
1233 | * get_new_inode() will do the right thing, re-trying the search |
1234 | * in case it had to block at any point. |
1235 | */ |
1236 | return get_new_inode(sb, head, test, set, data); |
1237 | } |
1238 | EXPORT_SYMBOL(iget5_locked); |
1239 | |
1240 | /** |
1241 | * iget_locked - obtain an inode from a mounted file system |
1242 | * @sb: super block of file system |
1243 | * @ino: inode number to get |
1244 | * |
1245 | * iget_locked() uses ifind_fast() to search for the inode specified by @ino in |
1246 | * the inode cache and if present it is returned with an increased reference |
1247 | * count. This is for file systems where the inode number is sufficient for |
1248 | * unique identification of an inode. |
1249 | * |
1250 | * If the inode is not in cache, get_new_inode_fast() is called to allocate a |
1251 | * new inode and this is returned locked, hashed, and with the I_NEW flag set. |
1252 | * The file system gets to fill it in before unlocking it via |
1253 | * unlock_new_inode(). |
1254 | */ |
1255 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1256 | { |
1257 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1258 | struct inode *inode; |
1259 | |
1260 | inode = ifind_fast(sb, head, ino); |
1261 | if (inode) |
1262 | return inode; |
1263 | /* |
1264 | * get_new_inode_fast() will do the right thing, re-trying the search |
1265 | * in case it had to block at any point. |
1266 | */ |
1267 | return get_new_inode_fast(sb, head, ino); |
1268 | } |
1269 | EXPORT_SYMBOL(iget_locked); |
1270 | |
1271 | int insert_inode_locked(struct inode *inode) |
1272 | { |
1273 | struct super_block *sb = inode->i_sb; |
1274 | ino_t ino = inode->i_ino; |
1275 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1276 | |
1277 | inode->i_state |= I_NEW; |
1278 | while (1) { |
1279 | struct hlist_node *node; |
1280 | struct inode *old = NULL; |
1281 | spin_lock(&inode_lock); |
1282 | hlist_for_each_entry(old, node, head, i_hash) { |
1283 | if (old->i_ino != ino) |
1284 | continue; |
1285 | if (old->i_sb != sb) |
1286 | continue; |
1287 | if (old->i_state & (I_FREEING|I_WILL_FREE)) |
1288 | continue; |
1289 | break; |
1290 | } |
1291 | if (likely(!node)) { |
1292 | hlist_add_head(&inode->i_hash, head); |
1293 | spin_unlock(&inode_lock); |
1294 | return 0; |
1295 | } |
1296 | __iget(old); |
1297 | spin_unlock(&inode_lock); |
1298 | wait_on_inode(old); |
1299 | if (unlikely(!inode_unhashed(old))) { |
1300 | iput(old); |
1301 | return -EBUSY; |
1302 | } |
1303 | iput(old); |
1304 | } |
1305 | } |
1306 | EXPORT_SYMBOL(insert_inode_locked); |
1307 | |
1308 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1309 | int (*test)(struct inode *, void *), void *data) |
1310 | { |
1311 | struct super_block *sb = inode->i_sb; |
1312 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1313 | |
1314 | inode->i_state |= I_NEW; |
1315 | |
1316 | while (1) { |
1317 | struct hlist_node *node; |
1318 | struct inode *old = NULL; |
1319 | |
1320 | spin_lock(&inode_lock); |
1321 | hlist_for_each_entry(old, node, head, i_hash) { |
1322 | if (old->i_sb != sb) |
1323 | continue; |
1324 | if (!test(old, data)) |
1325 | continue; |
1326 | if (old->i_state & (I_FREEING|I_WILL_FREE)) |
1327 | continue; |
1328 | break; |
1329 | } |
1330 | if (likely(!node)) { |
1331 | hlist_add_head(&inode->i_hash, head); |
1332 | spin_unlock(&inode_lock); |
1333 | return 0; |
1334 | } |
1335 | __iget(old); |
1336 | spin_unlock(&inode_lock); |
1337 | wait_on_inode(old); |
1338 | if (unlikely(!inode_unhashed(old))) { |
1339 | iput(old); |
1340 | return -EBUSY; |
1341 | } |
1342 | iput(old); |
1343 | } |
1344 | } |
1345 | EXPORT_SYMBOL(insert_inode_locked4); |
1346 | |
1347 | |
1348 | int generic_delete_inode(struct inode *inode) |
1349 | { |
1350 | return 1; |
1351 | } |
1352 | EXPORT_SYMBOL(generic_delete_inode); |
1353 | |
1354 | /* |
1355 | * Normal UNIX filesystem behaviour: delete the |
1356 | * inode when the usage count drops to zero, and |
1357 | * i_nlink is zero. |
1358 | */ |
1359 | int generic_drop_inode(struct inode *inode) |
1360 | { |
1361 | return !inode->i_nlink || inode_unhashed(inode); |
1362 | } |
1363 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1364 | |
1365 | /* |
1366 | * Called when we're dropping the last reference |
1367 | * to an inode. |
1368 | * |
1369 | * Call the FS "drop_inode()" function, defaulting to |
1370 | * the legacy UNIX filesystem behaviour. If it tells |
1371 | * us to evict inode, do so. Otherwise, retain inode |
1372 | * in cache if fs is alive, sync and evict if fs is |
1373 | * shutting down. |
1374 | */ |
1375 | static void iput_final(struct inode *inode) |
1376 | { |
1377 | struct super_block *sb = inode->i_sb; |
1378 | const struct super_operations *op = inode->i_sb->s_op; |
1379 | int drop; |
1380 | |
1381 | if (op && op->drop_inode) |
1382 | drop = op->drop_inode(inode); |
1383 | else |
1384 | drop = generic_drop_inode(inode); |
1385 | |
1386 | if (!drop) { |
1387 | if (sb->s_flags & MS_ACTIVE) { |
1388 | inode->i_state |= I_REFERENCED; |
1389 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) { |
1390 | inode_lru_list_add(inode); |
1391 | } |
1392 | spin_unlock(&inode_lock); |
1393 | return; |
1394 | } |
1395 | WARN_ON(inode->i_state & I_NEW); |
1396 | inode->i_state |= I_WILL_FREE; |
1397 | spin_unlock(&inode_lock); |
1398 | write_inode_now(inode, 1); |
1399 | spin_lock(&inode_lock); |
1400 | WARN_ON(inode->i_state & I_NEW); |
1401 | inode->i_state &= ~I_WILL_FREE; |
1402 | __remove_inode_hash(inode); |
1403 | } |
1404 | |
1405 | WARN_ON(inode->i_state & I_NEW); |
1406 | inode->i_state |= I_FREEING; |
1407 | |
1408 | /* |
1409 | * Move the inode off the IO lists and LRU once I_FREEING is |
1410 | * set so that it won't get moved back on there if it is dirty. |
1411 | */ |
1412 | inode_lru_list_del(inode); |
1413 | list_del_init(&inode->i_wb_list); |
1414 | |
1415 | __inode_sb_list_del(inode); |
1416 | spin_unlock(&inode_lock); |
1417 | evict(inode); |
1418 | remove_inode_hash(inode); |
1419 | wake_up_inode(inode); |
1420 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
1421 | destroy_inode(inode); |
1422 | } |
1423 | |
1424 | /** |
1425 | * iput - put an inode |
1426 | * @inode: inode to put |
1427 | * |
1428 | * Puts an inode, dropping its usage count. If the inode use count hits |
1429 | * zero, the inode is then freed and may also be destroyed. |
1430 | * |
1431 | * Consequently, iput() can sleep. |
1432 | */ |
1433 | void iput(struct inode *inode) |
1434 | { |
1435 | if (inode) { |
1436 | BUG_ON(inode->i_state & I_CLEAR); |
1437 | |
1438 | if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) |
1439 | iput_final(inode); |
1440 | } |
1441 | } |
1442 | EXPORT_SYMBOL(iput); |
1443 | |
1444 | /** |
1445 | * bmap - find a block number in a file |
1446 | * @inode: inode of file |
1447 | * @block: block to find |
1448 | * |
1449 | * Returns the block number on the device holding the inode that |
1450 | * is the disk block number for the block of the file requested. |
1451 | * That is, asked for block 4 of inode 1 the function will return the |
1452 | * disk block relative to the disk start that holds that block of the |
1453 | * file. |
1454 | */ |
1455 | sector_t bmap(struct inode *inode, sector_t block) |
1456 | { |
1457 | sector_t res = 0; |
1458 | if (inode->i_mapping->a_ops->bmap) |
1459 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
1460 | return res; |
1461 | } |
1462 | EXPORT_SYMBOL(bmap); |
1463 | |
1464 | /* |
1465 | * With relative atime, only update atime if the previous atime is |
1466 | * earlier than either the ctime or mtime or if at least a day has |
1467 | * passed since the last atime update. |
1468 | */ |
1469 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1470 | struct timespec now) |
1471 | { |
1472 | |
1473 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1474 | return 1; |
1475 | /* |
1476 | * Is mtime younger than atime? If yes, update atime: |
1477 | */ |
1478 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
1479 | return 1; |
1480 | /* |
1481 | * Is ctime younger than atime? If yes, update atime: |
1482 | */ |
1483 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
1484 | return 1; |
1485 | |
1486 | /* |
1487 | * Is the previous atime value older than a day? If yes, |
1488 | * update atime: |
1489 | */ |
1490 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
1491 | return 1; |
1492 | /* |
1493 | * Good, we can skip the atime update: |
1494 | */ |
1495 | return 0; |
1496 | } |
1497 | |
1498 | /** |
1499 | * touch_atime - update the access time |
1500 | * @mnt: mount the inode is accessed on |
1501 | * @dentry: dentry accessed |
1502 | * |
1503 | * Update the accessed time on an inode and mark it for writeback. |
1504 | * This function automatically handles read only file systems and media, |
1505 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1506 | */ |
1507 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1508 | { |
1509 | struct inode *inode = dentry->d_inode; |
1510 | struct timespec now; |
1511 | |
1512 | if (inode->i_flags & S_NOATIME) |
1513 | return; |
1514 | if (IS_NOATIME(inode)) |
1515 | return; |
1516 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1517 | return; |
1518 | |
1519 | if (mnt->mnt_flags & MNT_NOATIME) |
1520 | return; |
1521 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1522 | return; |
1523 | |
1524 | now = current_fs_time(inode->i_sb); |
1525 | |
1526 | if (!relatime_need_update(mnt, inode, now)) |
1527 | return; |
1528 | |
1529 | if (timespec_equal(&inode->i_atime, &now)) |
1530 | return; |
1531 | |
1532 | if (mnt_want_write(mnt)) |
1533 | return; |
1534 | |
1535 | inode->i_atime = now; |
1536 | mark_inode_dirty_sync(inode); |
1537 | mnt_drop_write(mnt); |
1538 | } |
1539 | EXPORT_SYMBOL(touch_atime); |
1540 | |
1541 | /** |
1542 | * file_update_time - update mtime and ctime time |
1543 | * @file: file accessed |
1544 | * |
1545 | * Update the mtime and ctime members of an inode and mark the inode |
1546 | * for writeback. Note that this function is meant exclusively for |
1547 | * usage in the file write path of filesystems, and filesystems may |
1548 | * choose to explicitly ignore update via this function with the |
1549 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
1550 | * timestamps are handled by the server. |
1551 | */ |
1552 | |
1553 | void file_update_time(struct file *file) |
1554 | { |
1555 | struct inode *inode = file->f_path.dentry->d_inode; |
1556 | struct timespec now; |
1557 | enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0; |
1558 | |
1559 | /* First try to exhaust all avenues to not sync */ |
1560 | if (IS_NOCMTIME(inode)) |
1561 | return; |
1562 | |
1563 | now = current_fs_time(inode->i_sb); |
1564 | if (!timespec_equal(&inode->i_mtime, &now)) |
1565 | sync_it = S_MTIME; |
1566 | |
1567 | if (!timespec_equal(&inode->i_ctime, &now)) |
1568 | sync_it |= S_CTIME; |
1569 | |
1570 | if (IS_I_VERSION(inode)) |
1571 | sync_it |= S_VERSION; |
1572 | |
1573 | if (!sync_it) |
1574 | return; |
1575 | |
1576 | /* Finally allowed to write? Takes lock. */ |
1577 | if (mnt_want_write_file(file)) |
1578 | return; |
1579 | |
1580 | /* Only change inode inside the lock region */ |
1581 | if (sync_it & S_VERSION) |
1582 | inode_inc_iversion(inode); |
1583 | if (sync_it & S_CTIME) |
1584 | inode->i_ctime = now; |
1585 | if (sync_it & S_MTIME) |
1586 | inode->i_mtime = now; |
1587 | mark_inode_dirty_sync(inode); |
1588 | mnt_drop_write(file->f_path.mnt); |
1589 | } |
1590 | EXPORT_SYMBOL(file_update_time); |
1591 | |
1592 | int inode_needs_sync(struct inode *inode) |
1593 | { |
1594 | if (IS_SYNC(inode)) |
1595 | return 1; |
1596 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
1597 | return 1; |
1598 | return 0; |
1599 | } |
1600 | EXPORT_SYMBOL(inode_needs_sync); |
1601 | |
1602 | int inode_wait(void *word) |
1603 | { |
1604 | schedule(); |
1605 | return 0; |
1606 | } |
1607 | EXPORT_SYMBOL(inode_wait); |
1608 | |
1609 | /* |
1610 | * If we try to find an inode in the inode hash while it is being |
1611 | * deleted, we have to wait until the filesystem completes its |
1612 | * deletion before reporting that it isn't found. This function waits |
1613 | * until the deletion _might_ have completed. Callers are responsible |
1614 | * to recheck inode state. |
1615 | * |
1616 | * It doesn't matter if I_NEW is not set initially, a call to |
1617 | * wake_up_inode() after removing from the hash list will DTRT. |
1618 | * |
1619 | * This is called with inode_lock held. |
1620 | */ |
1621 | static void __wait_on_freeing_inode(struct inode *inode) |
1622 | { |
1623 | wait_queue_head_t *wq; |
1624 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
1625 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
1626 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
1627 | spin_unlock(&inode_lock); |
1628 | schedule(); |
1629 | finish_wait(wq, &wait.wait); |
1630 | spin_lock(&inode_lock); |
1631 | } |
1632 | |
1633 | static __initdata unsigned long ihash_entries; |
1634 | static int __init set_ihash_entries(char *str) |
1635 | { |
1636 | if (!str) |
1637 | return 0; |
1638 | ihash_entries = simple_strtoul(str, &str, 0); |
1639 | return 1; |
1640 | } |
1641 | __setup("ihash_entries=", set_ihash_entries); |
1642 | |
1643 | /* |
1644 | * Initialize the waitqueues and inode hash table. |
1645 | */ |
1646 | void __init inode_init_early(void) |
1647 | { |
1648 | int loop; |
1649 | |
1650 | /* If hashes are distributed across NUMA nodes, defer |
1651 | * hash allocation until vmalloc space is available. |
1652 | */ |
1653 | if (hashdist) |
1654 | return; |
1655 | |
1656 | inode_hashtable = |
1657 | alloc_large_system_hash("Inode-cache", |
1658 | sizeof(struct hlist_head), |
1659 | ihash_entries, |
1660 | 14, |
1661 | HASH_EARLY, |
1662 | &i_hash_shift, |
1663 | &i_hash_mask, |
1664 | 0); |
1665 | |
1666 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1667 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1668 | } |
1669 | |
1670 | void __init inode_init(void) |
1671 | { |
1672 | int loop; |
1673 | |
1674 | /* inode slab cache */ |
1675 | inode_cachep = kmem_cache_create("inode_cache", |
1676 | sizeof(struct inode), |
1677 | 0, |
1678 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
1679 | SLAB_MEM_SPREAD), |
1680 | init_once); |
1681 | register_shrinker(&icache_shrinker); |
1682 | |
1683 | /* Hash may have been set up in inode_init_early */ |
1684 | if (!hashdist) |
1685 | return; |
1686 | |
1687 | inode_hashtable = |
1688 | alloc_large_system_hash("Inode-cache", |
1689 | sizeof(struct hlist_head), |
1690 | ihash_entries, |
1691 | 14, |
1692 | 0, |
1693 | &i_hash_shift, |
1694 | &i_hash_mask, |
1695 | 0); |
1696 | |
1697 | for (loop = 0; loop < (1 << i_hash_shift); loop++) |
1698 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1699 | } |
1700 | |
1701 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
1702 | { |
1703 | inode->i_mode = mode; |
1704 | if (S_ISCHR(mode)) { |
1705 | inode->i_fop = &def_chr_fops; |
1706 | inode->i_rdev = rdev; |
1707 | } else if (S_ISBLK(mode)) { |
1708 | inode->i_fop = &def_blk_fops; |
1709 | inode->i_rdev = rdev; |
1710 | } else if (S_ISFIFO(mode)) |
1711 | inode->i_fop = &def_fifo_fops; |
1712 | else if (S_ISSOCK(mode)) |
1713 | inode->i_fop = &bad_sock_fops; |
1714 | else |
1715 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
1716 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
1717 | inode->i_ino); |
1718 | } |
1719 | EXPORT_SYMBOL(init_special_inode); |
1720 | |
1721 | /** |
1722 | * Init uid,gid,mode for new inode according to posix standards |
1723 | * @inode: New inode |
1724 | * @dir: Directory inode |
1725 | * @mode: mode of the new inode |
1726 | */ |
1727 | void inode_init_owner(struct inode *inode, const struct inode *dir, |
1728 | mode_t mode) |
1729 | { |
1730 | inode->i_uid = current_fsuid(); |
1731 | if (dir && dir->i_mode & S_ISGID) { |
1732 | inode->i_gid = dir->i_gid; |
1733 | if (S_ISDIR(mode)) |
1734 | mode |= S_ISGID; |
1735 | } else |
1736 | inode->i_gid = current_fsgid(); |
1737 | inode->i_mode = mode; |
1738 | } |
1739 | EXPORT_SYMBOL(inode_init_owner); |
1740 |
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