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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/export.h> |
6 | #include <linux/fs.h> |
7 | #include <linux/mm.h> |
8 | #include <linux/backing-dev.h> |
9 | #include <linux/hash.h> |
10 | #include <linux/swap.h> |
11 | #include <linux/security.h> |
12 | #include <linux/cdev.h> |
13 | #include <linux/bootmem.h> |
14 | #include <linux/fsnotify.h> |
15 | #include <linux/mount.h> |
16 | #include <linux/posix_acl.h> |
17 | #include <linux/prefetch.h> |
18 | #include <linux/buffer_head.h> /* for inode_has_buffers */ |
19 | #include <linux/ratelimit.h> |
20 | #include "internal.h" |
21 | |
22 | /* |
23 | * Inode locking rules: |
24 | * |
25 | * inode->i_lock protects: |
26 | * inode->i_state, inode->i_hash, __iget() |
27 | * inode->i_sb->s_inode_lru_lock protects: |
28 | * inode->i_sb->s_inode_lru, inode->i_lru |
29 | * inode_sb_list_lock protects: |
30 | * sb->s_inodes, inode->i_sb_list |
31 | * bdi->wb.list_lock protects: |
32 | * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list |
33 | * inode_hash_lock protects: |
34 | * inode_hashtable, inode->i_hash |
35 | * |
36 | * Lock ordering: |
37 | * |
38 | * inode_sb_list_lock |
39 | * inode->i_lock |
40 | * inode->i_sb->s_inode_lru_lock |
41 | * |
42 | * bdi->wb.list_lock |
43 | * inode->i_lock |
44 | * |
45 | * inode_hash_lock |
46 | * inode_sb_list_lock |
47 | * inode->i_lock |
48 | * |
49 | * iunique_lock |
50 | * inode_hash_lock |
51 | */ |
52 | |
53 | static unsigned int i_hash_mask __read_mostly; |
54 | static unsigned int i_hash_shift __read_mostly; |
55 | static struct hlist_head *inode_hashtable __read_mostly; |
56 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
57 | |
58 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock); |
59 | |
60 | /* |
61 | * Empty aops. Can be used for the cases where the user does not |
62 | * define any of the address_space operations. |
63 | */ |
64 | const struct address_space_operations empty_aops = { |
65 | }; |
66 | EXPORT_SYMBOL(empty_aops); |
67 | |
68 | /* |
69 | * Statistics gathering.. |
70 | */ |
71 | struct inodes_stat_t inodes_stat; |
72 | |
73 | static DEFINE_PER_CPU(unsigned int, nr_inodes); |
74 | static DEFINE_PER_CPU(unsigned int, nr_unused); |
75 | |
76 | static struct kmem_cache *inode_cachep __read_mostly; |
77 | |
78 | static int get_nr_inodes(void) |
79 | { |
80 | int i; |
81 | int sum = 0; |
82 | for_each_possible_cpu(i) |
83 | sum += per_cpu(nr_inodes, i); |
84 | return sum < 0 ? 0 : sum; |
85 | } |
86 | |
87 | static inline int get_nr_inodes_unused(void) |
88 | { |
89 | int i; |
90 | int sum = 0; |
91 | for_each_possible_cpu(i) |
92 | sum += per_cpu(nr_unused, i); |
93 | return sum < 0 ? 0 : sum; |
94 | } |
95 | |
96 | int get_nr_dirty_inodes(void) |
97 | { |
98 | /* not actually dirty inodes, but a wild approximation */ |
99 | int nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
100 | return nr_dirty > 0 ? nr_dirty : 0; |
101 | } |
102 | |
103 | /* |
104 | * Handle nr_inode sysctl |
105 | */ |
106 | #ifdef CONFIG_SYSCTL |
107 | int proc_nr_inodes(ctl_table *table, int write, |
108 | void __user *buffer, size_t *lenp, loff_t *ppos) |
109 | { |
110 | inodes_stat.nr_inodes = get_nr_inodes(); |
111 | inodes_stat.nr_unused = get_nr_inodes_unused(); |
112 | return proc_dointvec(table, write, buffer, lenp, ppos); |
113 | } |
114 | #endif |
115 | |
116 | /** |
117 | * inode_init_always - perform inode structure intialisation |
118 | * @sb: superblock inode belongs to |
119 | * @inode: inode to initialise |
120 | * |
121 | * These are initializations that need to be done on every inode |
122 | * allocation as the fields are not initialised by slab allocation. |
123 | */ |
124 | int inode_init_always(struct super_block *sb, struct inode *inode) |
125 | { |
126 | static const struct inode_operations empty_iops; |
127 | static const struct file_operations empty_fops; |
128 | struct address_space *const mapping = &inode->i_data; |
129 | |
130 | inode->i_sb = sb; |
131 | inode->i_blkbits = sb->s_blocksize_bits; |
132 | inode->i_flags = 0; |
133 | atomic_set(&inode->i_count, 1); |
134 | inode->i_op = &empty_iops; |
135 | inode->i_fop = &empty_fops; |
136 | inode->__i_nlink = 1; |
137 | inode->i_opflags = 0; |
138 | i_uid_write(inode, 0); |
139 | i_gid_write(inode, 0); |
140 | atomic_set(&inode->i_writecount, 0); |
141 | inode->i_size = 0; |
142 | inode->i_blocks = 0; |
143 | inode->i_bytes = 0; |
144 | inode->i_generation = 0; |
145 | #ifdef CONFIG_QUOTA |
146 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
147 | #endif |
148 | inode->i_pipe = NULL; |
149 | inode->i_bdev = NULL; |
150 | inode->i_cdev = NULL; |
151 | inode->i_rdev = 0; |
152 | inode->dirtied_when = 0; |
153 | |
154 | if (security_inode_alloc(inode)) |
155 | goto out; |
156 | spin_lock_init(&inode->i_lock); |
157 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
158 | |
159 | mutex_init(&inode->i_mutex); |
160 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
161 | |
162 | atomic_set(&inode->i_dio_count, 0); |
163 | |
164 | mapping->a_ops = &empty_aops; |
165 | mapping->host = inode; |
166 | mapping->flags = 0; |
167 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
168 | mapping->private_data = NULL; |
169 | mapping->backing_dev_info = &default_backing_dev_info; |
170 | mapping->writeback_index = 0; |
171 | |
172 | /* |
173 | * If the block_device provides a backing_dev_info for client |
174 | * inodes then use that. Otherwise the inode share the bdev's |
175 | * backing_dev_info. |
176 | */ |
177 | if (sb->s_bdev) { |
178 | struct backing_dev_info *bdi; |
179 | |
180 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
181 | mapping->backing_dev_info = bdi; |
182 | } |
183 | inode->i_private = NULL; |
184 | inode->i_mapping = mapping; |
185 | INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ |
186 | #ifdef CONFIG_FS_POSIX_ACL |
187 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
188 | #endif |
189 | |
190 | #ifdef CONFIG_FSNOTIFY |
191 | inode->i_fsnotify_mask = 0; |
192 | #endif |
193 | |
194 | this_cpu_inc(nr_inodes); |
195 | |
196 | return 0; |
197 | out: |
198 | return -ENOMEM; |
199 | } |
200 | EXPORT_SYMBOL(inode_init_always); |
201 | |
202 | static struct inode *alloc_inode(struct super_block *sb) |
203 | { |
204 | struct inode *inode; |
205 | |
206 | if (sb->s_op->alloc_inode) |
207 | inode = sb->s_op->alloc_inode(sb); |
208 | else |
209 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
210 | |
211 | if (!inode) |
212 | return NULL; |
213 | |
214 | if (unlikely(inode_init_always(sb, inode))) { |
215 | if (inode->i_sb->s_op->destroy_inode) |
216 | inode->i_sb->s_op->destroy_inode(inode); |
217 | else |
218 | kmem_cache_free(inode_cachep, inode); |
219 | return NULL; |
220 | } |
221 | |
222 | return inode; |
223 | } |
224 | |
225 | void free_inode_nonrcu(struct inode *inode) |
226 | { |
227 | kmem_cache_free(inode_cachep, inode); |
228 | } |
229 | EXPORT_SYMBOL(free_inode_nonrcu); |
230 | |
231 | void __destroy_inode(struct inode *inode) |
232 | { |
233 | BUG_ON(inode_has_buffers(inode)); |
234 | security_inode_free(inode); |
235 | fsnotify_inode_delete(inode); |
236 | if (!inode->i_nlink) { |
237 | WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); |
238 | atomic_long_dec(&inode->i_sb->s_remove_count); |
239 | } |
240 | |
241 | #ifdef CONFIG_FS_POSIX_ACL |
242 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
243 | posix_acl_release(inode->i_acl); |
244 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
245 | posix_acl_release(inode->i_default_acl); |
246 | #endif |
247 | this_cpu_dec(nr_inodes); |
248 | } |
249 | EXPORT_SYMBOL(__destroy_inode); |
250 | |
251 | static void i_callback(struct rcu_head *head) |
252 | { |
253 | struct inode *inode = container_of(head, struct inode, i_rcu); |
254 | kmem_cache_free(inode_cachep, inode); |
255 | } |
256 | |
257 | static void destroy_inode(struct inode *inode) |
258 | { |
259 | BUG_ON(!list_empty(&inode->i_lru)); |
260 | __destroy_inode(inode); |
261 | if (inode->i_sb->s_op->destroy_inode) |
262 | inode->i_sb->s_op->destroy_inode(inode); |
263 | else |
264 | call_rcu(&inode->i_rcu, i_callback); |
265 | } |
266 | |
267 | /** |
268 | * drop_nlink - directly drop an inode's link count |
269 | * @inode: inode |
270 | * |
271 | * This is a low-level filesystem helper to replace any |
272 | * direct filesystem manipulation of i_nlink. In cases |
273 | * where we are attempting to track writes to the |
274 | * filesystem, a decrement to zero means an imminent |
275 | * write when the file is truncated and actually unlinked |
276 | * on the filesystem. |
277 | */ |
278 | void drop_nlink(struct inode *inode) |
279 | { |
280 | WARN_ON(inode->i_nlink == 0); |
281 | inode->__i_nlink--; |
282 | if (!inode->i_nlink) |
283 | atomic_long_inc(&inode->i_sb->s_remove_count); |
284 | } |
285 | EXPORT_SYMBOL(drop_nlink); |
286 | |
287 | /** |
288 | * clear_nlink - directly zero an inode's link count |
289 | * @inode: inode |
290 | * |
291 | * This is a low-level filesystem helper to replace any |
292 | * direct filesystem manipulation of i_nlink. See |
293 | * drop_nlink() for why we care about i_nlink hitting zero. |
294 | */ |
295 | void clear_nlink(struct inode *inode) |
296 | { |
297 | if (inode->i_nlink) { |
298 | inode->__i_nlink = 0; |
299 | atomic_long_inc(&inode->i_sb->s_remove_count); |
300 | } |
301 | } |
302 | EXPORT_SYMBOL(clear_nlink); |
303 | |
304 | /** |
305 | * set_nlink - directly set an inode's link count |
306 | * @inode: inode |
307 | * @nlink: new nlink (should be non-zero) |
308 | * |
309 | * This is a low-level filesystem helper to replace any |
310 | * direct filesystem manipulation of i_nlink. |
311 | */ |
312 | void set_nlink(struct inode *inode, unsigned int nlink) |
313 | { |
314 | if (!nlink) { |
315 | clear_nlink(inode); |
316 | } else { |
317 | /* Yes, some filesystems do change nlink from zero to one */ |
318 | if (inode->i_nlink == 0) |
319 | atomic_long_dec(&inode->i_sb->s_remove_count); |
320 | |
321 | inode->__i_nlink = nlink; |
322 | } |
323 | } |
324 | EXPORT_SYMBOL(set_nlink); |
325 | |
326 | /** |
327 | * inc_nlink - directly increment an inode's link count |
328 | * @inode: inode |
329 | * |
330 | * This is a low-level filesystem helper to replace any |
331 | * direct filesystem manipulation of i_nlink. Currently, |
332 | * it is only here for parity with dec_nlink(). |
333 | */ |
334 | void inc_nlink(struct inode *inode) |
335 | { |
336 | if (WARN_ON(inode->i_nlink == 0)) |
337 | atomic_long_dec(&inode->i_sb->s_remove_count); |
338 | |
339 | inode->__i_nlink++; |
340 | } |
341 | EXPORT_SYMBOL(inc_nlink); |
342 | |
343 | void address_space_init_once(struct address_space *mapping) |
344 | { |
345 | memset(mapping, 0, sizeof(*mapping)); |
346 | INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); |
347 | spin_lock_init(&mapping->tree_lock); |
348 | mutex_init(&mapping->i_mmap_mutex); |
349 | INIT_LIST_HEAD(&mapping->private_list); |
350 | spin_lock_init(&mapping->private_lock); |
351 | mapping->i_mmap = RB_ROOT; |
352 | INIT_LIST_HEAD(&mapping->i_mmap_nonlinear); |
353 | } |
354 | EXPORT_SYMBOL(address_space_init_once); |
355 | |
356 | /* |
357 | * These are initializations that only need to be done |
358 | * once, because the fields are idempotent across use |
359 | * of the inode, so let the slab aware of that. |
360 | */ |
361 | void inode_init_once(struct inode *inode) |
362 | { |
363 | memset(inode, 0, sizeof(*inode)); |
364 | INIT_HLIST_NODE(&inode->i_hash); |
365 | INIT_LIST_HEAD(&inode->i_devices); |
366 | INIT_LIST_HEAD(&inode->i_wb_list); |
367 | INIT_LIST_HEAD(&inode->i_lru); |
368 | address_space_init_once(&inode->i_data); |
369 | i_size_ordered_init(inode); |
370 | #ifdef CONFIG_FSNOTIFY |
371 | INIT_HLIST_HEAD(&inode->i_fsnotify_marks); |
372 | #endif |
373 | } |
374 | EXPORT_SYMBOL(inode_init_once); |
375 | |
376 | static void init_once(void *foo) |
377 | { |
378 | struct inode *inode = (struct inode *) foo; |
379 | |
380 | inode_init_once(inode); |
381 | } |
382 | |
383 | /* |
384 | * inode->i_lock must be held |
385 | */ |
386 | void __iget(struct inode *inode) |
387 | { |
388 | atomic_inc(&inode->i_count); |
389 | } |
390 | |
391 | /* |
392 | * get additional reference to inode; caller must already hold one. |
393 | */ |
394 | void ihold(struct inode *inode) |
395 | { |
396 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
397 | } |
398 | EXPORT_SYMBOL(ihold); |
399 | |
400 | static void inode_lru_list_add(struct inode *inode) |
401 | { |
402 | spin_lock(&inode->i_sb->s_inode_lru_lock); |
403 | if (list_empty(&inode->i_lru)) { |
404 | list_add(&inode->i_lru, &inode->i_sb->s_inode_lru); |
405 | inode->i_sb->s_nr_inodes_unused++; |
406 | this_cpu_inc(nr_unused); |
407 | } |
408 | spin_unlock(&inode->i_sb->s_inode_lru_lock); |
409 | } |
410 | |
411 | /* |
412 | * Add inode to LRU if needed (inode is unused and clean). |
413 | * |
414 | * Needs inode->i_lock held. |
415 | */ |
416 | void inode_add_lru(struct inode *inode) |
417 | { |
418 | if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) && |
419 | !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE) |
420 | inode_lru_list_add(inode); |
421 | } |
422 | |
423 | |
424 | static void inode_lru_list_del(struct inode *inode) |
425 | { |
426 | spin_lock(&inode->i_sb->s_inode_lru_lock); |
427 | if (!list_empty(&inode->i_lru)) { |
428 | list_del_init(&inode->i_lru); |
429 | inode->i_sb->s_nr_inodes_unused--; |
430 | this_cpu_dec(nr_unused); |
431 | } |
432 | spin_unlock(&inode->i_sb->s_inode_lru_lock); |
433 | } |
434 | |
435 | /** |
436 | * inode_sb_list_add - add inode to the superblock list of inodes |
437 | * @inode: inode to add |
438 | */ |
439 | void inode_sb_list_add(struct inode *inode) |
440 | { |
441 | spin_lock(&inode_sb_list_lock); |
442 | list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
443 | spin_unlock(&inode_sb_list_lock); |
444 | } |
445 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
446 | |
447 | static inline void inode_sb_list_del(struct inode *inode) |
448 | { |
449 | if (!list_empty(&inode->i_sb_list)) { |
450 | spin_lock(&inode_sb_list_lock); |
451 | list_del_init(&inode->i_sb_list); |
452 | spin_unlock(&inode_sb_list_lock); |
453 | } |
454 | } |
455 | |
456 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
457 | { |
458 | unsigned long tmp; |
459 | |
460 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
461 | L1_CACHE_BYTES; |
462 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
463 | return tmp & i_hash_mask; |
464 | } |
465 | |
466 | /** |
467 | * __insert_inode_hash - hash an inode |
468 | * @inode: unhashed inode |
469 | * @hashval: unsigned long value used to locate this object in the |
470 | * inode_hashtable. |
471 | * |
472 | * Add an inode to the inode hash for this superblock. |
473 | */ |
474 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
475 | { |
476 | struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
477 | |
478 | spin_lock(&inode_hash_lock); |
479 | spin_lock(&inode->i_lock); |
480 | hlist_add_head(&inode->i_hash, b); |
481 | spin_unlock(&inode->i_lock); |
482 | spin_unlock(&inode_hash_lock); |
483 | } |
484 | EXPORT_SYMBOL(__insert_inode_hash); |
485 | |
486 | /** |
487 | * __remove_inode_hash - remove an inode from the hash |
488 | * @inode: inode to unhash |
489 | * |
490 | * Remove an inode from the superblock. |
491 | */ |
492 | void __remove_inode_hash(struct inode *inode) |
493 | { |
494 | spin_lock(&inode_hash_lock); |
495 | spin_lock(&inode->i_lock); |
496 | hlist_del_init(&inode->i_hash); |
497 | spin_unlock(&inode->i_lock); |
498 | spin_unlock(&inode_hash_lock); |
499 | } |
500 | EXPORT_SYMBOL(__remove_inode_hash); |
501 | |
502 | void clear_inode(struct inode *inode) |
503 | { |
504 | might_sleep(); |
505 | /* |
506 | * We have to cycle tree_lock here because reclaim can be still in the |
507 | * process of removing the last page (in __delete_from_page_cache()) |
508 | * and we must not free mapping under it. |
509 | */ |
510 | spin_lock_irq(&inode->i_data.tree_lock); |
511 | BUG_ON(inode->i_data.nrpages); |
512 | spin_unlock_irq(&inode->i_data.tree_lock); |
513 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
514 | BUG_ON(!(inode->i_state & I_FREEING)); |
515 | BUG_ON(inode->i_state & I_CLEAR); |
516 | /* don't need i_lock here, no concurrent mods to i_state */ |
517 | inode->i_state = I_FREEING | I_CLEAR; |
518 | } |
519 | EXPORT_SYMBOL(clear_inode); |
520 | |
521 | /* |
522 | * Free the inode passed in, removing it from the lists it is still connected |
523 | * to. We remove any pages still attached to the inode and wait for any IO that |
524 | * is still in progress before finally destroying the inode. |
525 | * |
526 | * An inode must already be marked I_FREEING so that we avoid the inode being |
527 | * moved back onto lists if we race with other code that manipulates the lists |
528 | * (e.g. writeback_single_inode). The caller is responsible for setting this. |
529 | * |
530 | * An inode must already be removed from the LRU list before being evicted from |
531 | * the cache. This should occur atomically with setting the I_FREEING state |
532 | * flag, so no inodes here should ever be on the LRU when being evicted. |
533 | */ |
534 | static void evict(struct inode *inode) |
535 | { |
536 | const struct super_operations *op = inode->i_sb->s_op; |
537 | |
538 | BUG_ON(!(inode->i_state & I_FREEING)); |
539 | BUG_ON(!list_empty(&inode->i_lru)); |
540 | |
541 | if (!list_empty(&inode->i_wb_list)) |
542 | inode_wb_list_del(inode); |
543 | |
544 | inode_sb_list_del(inode); |
545 | |
546 | /* |
547 | * Wait for flusher thread to be done with the inode so that filesystem |
548 | * does not start destroying it while writeback is still running. Since |
549 | * the inode has I_FREEING set, flusher thread won't start new work on |
550 | * the inode. We just have to wait for running writeback to finish. |
551 | */ |
552 | inode_wait_for_writeback(inode); |
553 | |
554 | if (op->evict_inode) { |
555 | op->evict_inode(inode); |
556 | } else { |
557 | if (inode->i_data.nrpages) |
558 | truncate_inode_pages(&inode->i_data, 0); |
559 | clear_inode(inode); |
560 | } |
561 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
562 | bd_forget(inode); |
563 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
564 | cd_forget(inode); |
565 | |
566 | remove_inode_hash(inode); |
567 | |
568 | spin_lock(&inode->i_lock); |
569 | wake_up_bit(&inode->i_state, __I_NEW); |
570 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
571 | spin_unlock(&inode->i_lock); |
572 | |
573 | destroy_inode(inode); |
574 | } |
575 | |
576 | /* |
577 | * dispose_list - dispose of the contents of a local list |
578 | * @head: the head of the list to free |
579 | * |
580 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
581 | * need to worry about list corruption and SMP locks. |
582 | */ |
583 | static void dispose_list(struct list_head *head) |
584 | { |
585 | while (!list_empty(head)) { |
586 | struct inode *inode; |
587 | |
588 | inode = list_first_entry(head, struct inode, i_lru); |
589 | list_del_init(&inode->i_lru); |
590 | |
591 | evict(inode); |
592 | } |
593 | } |
594 | |
595 | /** |
596 | * evict_inodes - evict all evictable inodes for a superblock |
597 | * @sb: superblock to operate on |
598 | * |
599 | * Make sure that no inodes with zero refcount are retained. This is |
600 | * called by superblock shutdown after having MS_ACTIVE flag removed, |
601 | * so any inode reaching zero refcount during or after that call will |
602 | * be immediately evicted. |
603 | */ |
604 | void evict_inodes(struct super_block *sb) |
605 | { |
606 | struct inode *inode, *next; |
607 | LIST_HEAD(dispose); |
608 | |
609 | spin_lock(&inode_sb_list_lock); |
610 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
611 | if (atomic_read(&inode->i_count)) |
612 | continue; |
613 | |
614 | spin_lock(&inode->i_lock); |
615 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
616 | spin_unlock(&inode->i_lock); |
617 | continue; |
618 | } |
619 | |
620 | inode->i_state |= I_FREEING; |
621 | inode_lru_list_del(inode); |
622 | spin_unlock(&inode->i_lock); |
623 | list_add(&inode->i_lru, &dispose); |
624 | } |
625 | spin_unlock(&inode_sb_list_lock); |
626 | |
627 | dispose_list(&dispose); |
628 | } |
629 | |
630 | /** |
631 | * invalidate_inodes - attempt to free all inodes on a superblock |
632 | * @sb: superblock to operate on |
633 | * @kill_dirty: flag to guide handling of dirty inodes |
634 | * |
635 | * Attempts to free all inodes for a given superblock. If there were any |
636 | * busy inodes return a non-zero value, else zero. |
637 | * If @kill_dirty is set, discard dirty inodes too, otherwise treat |
638 | * them as busy. |
639 | */ |
640 | int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
641 | { |
642 | int busy = 0; |
643 | struct inode *inode, *next; |
644 | LIST_HEAD(dispose); |
645 | |
646 | spin_lock(&inode_sb_list_lock); |
647 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
648 | spin_lock(&inode->i_lock); |
649 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
650 | spin_unlock(&inode->i_lock); |
651 | continue; |
652 | } |
653 | if (inode->i_state & I_DIRTY && !kill_dirty) { |
654 | spin_unlock(&inode->i_lock); |
655 | busy = 1; |
656 | continue; |
657 | } |
658 | if (atomic_read(&inode->i_count)) { |
659 | spin_unlock(&inode->i_lock); |
660 | busy = 1; |
661 | continue; |
662 | } |
663 | |
664 | inode->i_state |= I_FREEING; |
665 | inode_lru_list_del(inode); |
666 | spin_unlock(&inode->i_lock); |
667 | list_add(&inode->i_lru, &dispose); |
668 | } |
669 | spin_unlock(&inode_sb_list_lock); |
670 | |
671 | dispose_list(&dispose); |
672 | |
673 | return busy; |
674 | } |
675 | |
676 | static int can_unuse(struct inode *inode) |
677 | { |
678 | if (inode->i_state & ~I_REFERENCED) |
679 | return 0; |
680 | if (inode_has_buffers(inode)) |
681 | return 0; |
682 | if (atomic_read(&inode->i_count)) |
683 | return 0; |
684 | if (inode->i_data.nrpages) |
685 | return 0; |
686 | return 1; |
687 | } |
688 | |
689 | /* |
690 | * Walk the superblock inode LRU for freeable inodes and attempt to free them. |
691 | * This is called from the superblock shrinker function with a number of inodes |
692 | * to trim from the LRU. Inodes to be freed are moved to a temporary list and |
693 | * then are freed outside inode_lock by dispose_list(). |
694 | * |
695 | * Any inodes which are pinned purely because of attached pagecache have their |
696 | * pagecache removed. If the inode has metadata buffers attached to |
697 | * mapping->private_list then try to remove them. |
698 | * |
699 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
700 | * used recently - the flag is set in iput_final(). When we encounter such an |
701 | * inode, clear the flag and move it to the back of the LRU so it gets another |
702 | * pass through the LRU before it gets reclaimed. This is necessary because of |
703 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
704 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
705 | * with this flag set because they are the inodes that are out of order. |
706 | */ |
707 | void prune_icache_sb(struct super_block *sb, int nr_to_scan) |
708 | { |
709 | LIST_HEAD(freeable); |
710 | int nr_scanned; |
711 | unsigned long reap = 0; |
712 | |
713 | spin_lock(&sb->s_inode_lru_lock); |
714 | for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) { |
715 | struct inode *inode; |
716 | |
717 | if (list_empty(&sb->s_inode_lru)) |
718 | break; |
719 | |
720 | inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru); |
721 | |
722 | /* |
723 | * we are inverting the sb->s_inode_lru_lock/inode->i_lock here, |
724 | * so use a trylock. If we fail to get the lock, just move the |
725 | * inode to the back of the list so we don't spin on it. |
726 | */ |
727 | if (!spin_trylock(&inode->i_lock)) { |
728 | list_move(&inode->i_lru, &sb->s_inode_lru); |
729 | continue; |
730 | } |
731 | |
732 | /* |
733 | * Referenced or dirty inodes are still in use. Give them |
734 | * another pass through the LRU as we canot reclaim them now. |
735 | */ |
736 | if (atomic_read(&inode->i_count) || |
737 | (inode->i_state & ~I_REFERENCED)) { |
738 | list_del_init(&inode->i_lru); |
739 | spin_unlock(&inode->i_lock); |
740 | sb->s_nr_inodes_unused--; |
741 | this_cpu_dec(nr_unused); |
742 | continue; |
743 | } |
744 | |
745 | /* recently referenced inodes get one more pass */ |
746 | if (inode->i_state & I_REFERENCED) { |
747 | inode->i_state &= ~I_REFERENCED; |
748 | list_move(&inode->i_lru, &sb->s_inode_lru); |
749 | spin_unlock(&inode->i_lock); |
750 | continue; |
751 | } |
752 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
753 | __iget(inode); |
754 | spin_unlock(&inode->i_lock); |
755 | spin_unlock(&sb->s_inode_lru_lock); |
756 | if (remove_inode_buffers(inode)) |
757 | reap += invalidate_mapping_pages(&inode->i_data, |
758 | 0, -1); |
759 | iput(inode); |
760 | spin_lock(&sb->s_inode_lru_lock); |
761 | |
762 | if (inode != list_entry(sb->s_inode_lru.next, |
763 | struct inode, i_lru)) |
764 | continue; /* wrong inode or list_empty */ |
765 | /* avoid lock inversions with trylock */ |
766 | if (!spin_trylock(&inode->i_lock)) |
767 | continue; |
768 | if (!can_unuse(inode)) { |
769 | spin_unlock(&inode->i_lock); |
770 | continue; |
771 | } |
772 | } |
773 | WARN_ON(inode->i_state & I_NEW); |
774 | inode->i_state |= I_FREEING; |
775 | spin_unlock(&inode->i_lock); |
776 | |
777 | list_move(&inode->i_lru, &freeable); |
778 | sb->s_nr_inodes_unused--; |
779 | this_cpu_dec(nr_unused); |
780 | } |
781 | if (current_is_kswapd()) |
782 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
783 | else |
784 | __count_vm_events(PGINODESTEAL, reap); |
785 | spin_unlock(&sb->s_inode_lru_lock); |
786 | if (current->reclaim_state) |
787 | current->reclaim_state->reclaimed_slab += reap; |
788 | |
789 | dispose_list(&freeable); |
790 | } |
791 | |
792 | static void __wait_on_freeing_inode(struct inode *inode); |
793 | /* |
794 | * Called with the inode lock held. |
795 | */ |
796 | static struct inode *find_inode(struct super_block *sb, |
797 | struct hlist_head *head, |
798 | int (*test)(struct inode *, void *), |
799 | void *data) |
800 | { |
801 | struct inode *inode = NULL; |
802 | |
803 | repeat: |
804 | hlist_for_each_entry(inode, head, i_hash) { |
805 | spin_lock(&inode->i_lock); |
806 | if (inode->i_sb != sb) { |
807 | spin_unlock(&inode->i_lock); |
808 | continue; |
809 | } |
810 | if (!test(inode, data)) { |
811 | spin_unlock(&inode->i_lock); |
812 | continue; |
813 | } |
814 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
815 | __wait_on_freeing_inode(inode); |
816 | goto repeat; |
817 | } |
818 | __iget(inode); |
819 | spin_unlock(&inode->i_lock); |
820 | return inode; |
821 | } |
822 | return NULL; |
823 | } |
824 | |
825 | /* |
826 | * find_inode_fast is the fast path version of find_inode, see the comment at |
827 | * iget_locked for details. |
828 | */ |
829 | static struct inode *find_inode_fast(struct super_block *sb, |
830 | struct hlist_head *head, unsigned long ino) |
831 | { |
832 | struct inode *inode = NULL; |
833 | |
834 | repeat: |
835 | hlist_for_each_entry(inode, head, i_hash) { |
836 | spin_lock(&inode->i_lock); |
837 | if (inode->i_ino != ino) { |
838 | spin_unlock(&inode->i_lock); |
839 | continue; |
840 | } |
841 | if (inode->i_sb != sb) { |
842 | spin_unlock(&inode->i_lock); |
843 | continue; |
844 | } |
845 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
846 | __wait_on_freeing_inode(inode); |
847 | goto repeat; |
848 | } |
849 | __iget(inode); |
850 | spin_unlock(&inode->i_lock); |
851 | return inode; |
852 | } |
853 | return NULL; |
854 | } |
855 | |
856 | /* |
857 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
858 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
859 | * to renew the exhausted range. |
860 | * |
861 | * This does not significantly increase overflow rate because every CPU can |
862 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
863 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
864 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
865 | * overflow rate by 2x, which does not seem too significant. |
866 | * |
867 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
868 | * error if st_ino won't fit in target struct field. Use 32bit counter |
869 | * here to attempt to avoid that. |
870 | */ |
871 | #define LAST_INO_BATCH 1024 |
872 | static DEFINE_PER_CPU(unsigned int, last_ino); |
873 | |
874 | unsigned int get_next_ino(void) |
875 | { |
876 | unsigned int *p = &get_cpu_var(last_ino); |
877 | unsigned int res = *p; |
878 | |
879 | #ifdef CONFIG_SMP |
880 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
881 | static atomic_t shared_last_ino; |
882 | int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
883 | |
884 | res = next - LAST_INO_BATCH; |
885 | } |
886 | #endif |
887 | |
888 | *p = ++res; |
889 | put_cpu_var(last_ino); |
890 | return res; |
891 | } |
892 | EXPORT_SYMBOL(get_next_ino); |
893 | |
894 | /** |
895 | * new_inode_pseudo - obtain an inode |
896 | * @sb: superblock |
897 | * |
898 | * Allocates a new inode for given superblock. |
899 | * Inode wont be chained in superblock s_inodes list |
900 | * This means : |
901 | * - fs can't be unmount |
902 | * - quotas, fsnotify, writeback can't work |
903 | */ |
904 | struct inode *new_inode_pseudo(struct super_block *sb) |
905 | { |
906 | struct inode *inode = alloc_inode(sb); |
907 | |
908 | if (inode) { |
909 | spin_lock(&inode->i_lock); |
910 | inode->i_state = 0; |
911 | spin_unlock(&inode->i_lock); |
912 | INIT_LIST_HEAD(&inode->i_sb_list); |
913 | } |
914 | return inode; |
915 | } |
916 | |
917 | /** |
918 | * new_inode - obtain an inode |
919 | * @sb: superblock |
920 | * |
921 | * Allocates a new inode for given superblock. The default gfp_mask |
922 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
923 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
924 | * for the page cache are not reclaimable or migratable, |
925 | * mapping_set_gfp_mask() must be called with suitable flags on the |
926 | * newly created inode's mapping |
927 | * |
928 | */ |
929 | struct inode *new_inode(struct super_block *sb) |
930 | { |
931 | struct inode *inode; |
932 | |
933 | spin_lock_prefetch(&inode_sb_list_lock); |
934 | |
935 | inode = new_inode_pseudo(sb); |
936 | if (inode) |
937 | inode_sb_list_add(inode); |
938 | return inode; |
939 | } |
940 | EXPORT_SYMBOL(new_inode); |
941 | |
942 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
943 | void lockdep_annotate_inode_mutex_key(struct inode *inode) |
944 | { |
945 | if (S_ISDIR(inode->i_mode)) { |
946 | struct file_system_type *type = inode->i_sb->s_type; |
947 | |
948 | /* Set new key only if filesystem hasn't already changed it */ |
949 | if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) { |
950 | /* |
951 | * ensure nobody is actually holding i_mutex |
952 | */ |
953 | mutex_destroy(&inode->i_mutex); |
954 | mutex_init(&inode->i_mutex); |
955 | lockdep_set_class(&inode->i_mutex, |
956 | &type->i_mutex_dir_key); |
957 | } |
958 | } |
959 | } |
960 | EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key); |
961 | #endif |
962 | |
963 | /** |
964 | * unlock_new_inode - clear the I_NEW state and wake up any waiters |
965 | * @inode: new inode to unlock |
966 | * |
967 | * Called when the inode is fully initialised to clear the new state of the |
968 | * inode and wake up anyone waiting for the inode to finish initialisation. |
969 | */ |
970 | void unlock_new_inode(struct inode *inode) |
971 | { |
972 | lockdep_annotate_inode_mutex_key(inode); |
973 | spin_lock(&inode->i_lock); |
974 | WARN_ON(!(inode->i_state & I_NEW)); |
975 | inode->i_state &= ~I_NEW; |
976 | smp_mb(); |
977 | wake_up_bit(&inode->i_state, __I_NEW); |
978 | spin_unlock(&inode->i_lock); |
979 | } |
980 | EXPORT_SYMBOL(unlock_new_inode); |
981 | |
982 | /** |
983 | * iget5_locked - obtain an inode from a mounted file system |
984 | * @sb: super block of file system |
985 | * @hashval: hash value (usually inode number) to get |
986 | * @test: callback used for comparisons between inodes |
987 | * @set: callback used to initialize a new struct inode |
988 | * @data: opaque data pointer to pass to @test and @set |
989 | * |
990 | * Search for the inode specified by @hashval and @data in the inode cache, |
991 | * and if present it is return it with an increased reference count. This is |
992 | * a generalized version of iget_locked() for file systems where the inode |
993 | * number is not sufficient for unique identification of an inode. |
994 | * |
995 | * If the inode is not in cache, allocate a new inode and return it locked, |
996 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
997 | * before unlocking it via unlock_new_inode(). |
998 | * |
999 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
1000 | * sleep. |
1001 | */ |
1002 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
1003 | int (*test)(struct inode *, void *), |
1004 | int (*set)(struct inode *, void *), void *data) |
1005 | { |
1006 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1007 | struct inode *inode; |
1008 | |
1009 | spin_lock(&inode_hash_lock); |
1010 | inode = find_inode(sb, head, test, data); |
1011 | spin_unlock(&inode_hash_lock); |
1012 | |
1013 | if (inode) { |
1014 | wait_on_inode(inode); |
1015 | return inode; |
1016 | } |
1017 | |
1018 | inode = alloc_inode(sb); |
1019 | if (inode) { |
1020 | struct inode *old; |
1021 | |
1022 | spin_lock(&inode_hash_lock); |
1023 | /* We released the lock, so.. */ |
1024 | old = find_inode(sb, head, test, data); |
1025 | if (!old) { |
1026 | if (set(inode, data)) |
1027 | goto set_failed; |
1028 | |
1029 | spin_lock(&inode->i_lock); |
1030 | inode->i_state = I_NEW; |
1031 | hlist_add_head(&inode->i_hash, head); |
1032 | spin_unlock(&inode->i_lock); |
1033 | inode_sb_list_add(inode); |
1034 | spin_unlock(&inode_hash_lock); |
1035 | |
1036 | /* Return the locked inode with I_NEW set, the |
1037 | * caller is responsible for filling in the contents |
1038 | */ |
1039 | return inode; |
1040 | } |
1041 | |
1042 | /* |
1043 | * Uhhuh, somebody else created the same inode under |
1044 | * us. Use the old inode instead of the one we just |
1045 | * allocated. |
1046 | */ |
1047 | spin_unlock(&inode_hash_lock); |
1048 | destroy_inode(inode); |
1049 | inode = old; |
1050 | wait_on_inode(inode); |
1051 | } |
1052 | return inode; |
1053 | |
1054 | set_failed: |
1055 | spin_unlock(&inode_hash_lock); |
1056 | destroy_inode(inode); |
1057 | return NULL; |
1058 | } |
1059 | EXPORT_SYMBOL(iget5_locked); |
1060 | |
1061 | /** |
1062 | * iget_locked - obtain an inode from a mounted file system |
1063 | * @sb: super block of file system |
1064 | * @ino: inode number to get |
1065 | * |
1066 | * Search for the inode specified by @ino in the inode cache and if present |
1067 | * return it with an increased reference count. This is for file systems |
1068 | * where the inode number is sufficient for unique identification of an inode. |
1069 | * |
1070 | * If the inode is not in cache, allocate a new inode and return it locked, |
1071 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
1072 | * before unlocking it via unlock_new_inode(). |
1073 | */ |
1074 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1075 | { |
1076 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1077 | struct inode *inode; |
1078 | |
1079 | spin_lock(&inode_hash_lock); |
1080 | inode = find_inode_fast(sb, head, ino); |
1081 | spin_unlock(&inode_hash_lock); |
1082 | if (inode) { |
1083 | wait_on_inode(inode); |
1084 | return inode; |
1085 | } |
1086 | |
1087 | inode = alloc_inode(sb); |
1088 | if (inode) { |
1089 | struct inode *old; |
1090 | |
1091 | spin_lock(&inode_hash_lock); |
1092 | /* We released the lock, so.. */ |
1093 | old = find_inode_fast(sb, head, ino); |
1094 | if (!old) { |
1095 | inode->i_ino = ino; |
1096 | spin_lock(&inode->i_lock); |
1097 | inode->i_state = I_NEW; |
1098 | hlist_add_head(&inode->i_hash, head); |
1099 | spin_unlock(&inode->i_lock); |
1100 | inode_sb_list_add(inode); |
1101 | spin_unlock(&inode_hash_lock); |
1102 | |
1103 | /* Return the locked inode with I_NEW set, the |
1104 | * caller is responsible for filling in the contents |
1105 | */ |
1106 | return inode; |
1107 | } |
1108 | |
1109 | /* |
1110 | * Uhhuh, somebody else created the same inode under |
1111 | * us. Use the old inode instead of the one we just |
1112 | * allocated. |
1113 | */ |
1114 | spin_unlock(&inode_hash_lock); |
1115 | destroy_inode(inode); |
1116 | inode = old; |
1117 | wait_on_inode(inode); |
1118 | } |
1119 | return inode; |
1120 | } |
1121 | EXPORT_SYMBOL(iget_locked); |
1122 | |
1123 | /* |
1124 | * search the inode cache for a matching inode number. |
1125 | * If we find one, then the inode number we are trying to |
1126 | * allocate is not unique and so we should not use it. |
1127 | * |
1128 | * Returns 1 if the inode number is unique, 0 if it is not. |
1129 | */ |
1130 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
1131 | { |
1132 | struct hlist_head *b = inode_hashtable + hash(sb, ino); |
1133 | struct inode *inode; |
1134 | |
1135 | spin_lock(&inode_hash_lock); |
1136 | hlist_for_each_entry(inode, b, i_hash) { |
1137 | if (inode->i_ino == ino && inode->i_sb == sb) { |
1138 | spin_unlock(&inode_hash_lock); |
1139 | return 0; |
1140 | } |
1141 | } |
1142 | spin_unlock(&inode_hash_lock); |
1143 | |
1144 | return 1; |
1145 | } |
1146 | |
1147 | /** |
1148 | * iunique - get a unique inode number |
1149 | * @sb: superblock |
1150 | * @max_reserved: highest reserved inode number |
1151 | * |
1152 | * Obtain an inode number that is unique on the system for a given |
1153 | * superblock. This is used by file systems that have no natural |
1154 | * permanent inode numbering system. An inode number is returned that |
1155 | * is higher than the reserved limit but unique. |
1156 | * |
1157 | * BUGS: |
1158 | * With a large number of inodes live on the file system this function |
1159 | * currently becomes quite slow. |
1160 | */ |
1161 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
1162 | { |
1163 | /* |
1164 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
1165 | * error if st_ino won't fit in target struct field. Use 32bit counter |
1166 | * here to attempt to avoid that. |
1167 | */ |
1168 | static DEFINE_SPINLOCK(iunique_lock); |
1169 | static unsigned int counter; |
1170 | ino_t res; |
1171 | |
1172 | spin_lock(&iunique_lock); |
1173 | do { |
1174 | if (counter <= max_reserved) |
1175 | counter = max_reserved + 1; |
1176 | res = counter++; |
1177 | } while (!test_inode_iunique(sb, res)); |
1178 | spin_unlock(&iunique_lock); |
1179 | |
1180 | return res; |
1181 | } |
1182 | EXPORT_SYMBOL(iunique); |
1183 | |
1184 | struct inode *igrab(struct inode *inode) |
1185 | { |
1186 | spin_lock(&inode->i_lock); |
1187 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
1188 | __iget(inode); |
1189 | spin_unlock(&inode->i_lock); |
1190 | } else { |
1191 | spin_unlock(&inode->i_lock); |
1192 | /* |
1193 | * Handle the case where s_op->clear_inode is not been |
1194 | * called yet, and somebody is calling igrab |
1195 | * while the inode is getting freed. |
1196 | */ |
1197 | inode = NULL; |
1198 | } |
1199 | return inode; |
1200 | } |
1201 | EXPORT_SYMBOL(igrab); |
1202 | |
1203 | /** |
1204 | * ilookup5_nowait - search for an inode in the inode cache |
1205 | * @sb: super block of file system to search |
1206 | * @hashval: hash value (usually inode number) to search for |
1207 | * @test: callback used for comparisons between inodes |
1208 | * @data: opaque data pointer to pass to @test |
1209 | * |
1210 | * Search for the inode specified by @hashval and @data in the inode cache. |
1211 | * If the inode is in the cache, the inode is returned with an incremented |
1212 | * reference count. |
1213 | * |
1214 | * Note: I_NEW is not waited upon so you have to be very careful what you do |
1215 | * with the returned inode. You probably should be using ilookup5() instead. |
1216 | * |
1217 | * Note2: @test is called with the inode_hash_lock held, so can't sleep. |
1218 | */ |
1219 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
1220 | int (*test)(struct inode *, void *), void *data) |
1221 | { |
1222 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1223 | struct inode *inode; |
1224 | |
1225 | spin_lock(&inode_hash_lock); |
1226 | inode = find_inode(sb, head, test, data); |
1227 | spin_unlock(&inode_hash_lock); |
1228 | |
1229 | return inode; |
1230 | } |
1231 | EXPORT_SYMBOL(ilookup5_nowait); |
1232 | |
1233 | /** |
1234 | * ilookup5 - search for an inode in the inode cache |
1235 | * @sb: super block of file system to search |
1236 | * @hashval: hash value (usually inode number) to search for |
1237 | * @test: callback used for comparisons between inodes |
1238 | * @data: opaque data pointer to pass to @test |
1239 | * |
1240 | * Search for the inode specified by @hashval and @data in the inode cache, |
1241 | * and if the inode is in the cache, return the inode with an incremented |
1242 | * reference count. Waits on I_NEW before returning the inode. |
1243 | * returned with an incremented reference count. |
1244 | * |
1245 | * This is a generalized version of ilookup() for file systems where the |
1246 | * inode number is not sufficient for unique identification of an inode. |
1247 | * |
1248 | * Note: @test is called with the inode_hash_lock held, so can't sleep. |
1249 | */ |
1250 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
1251 | int (*test)(struct inode *, void *), void *data) |
1252 | { |
1253 | struct inode *inode = ilookup5_nowait(sb, hashval, test, data); |
1254 | |
1255 | if (inode) |
1256 | wait_on_inode(inode); |
1257 | return inode; |
1258 | } |
1259 | EXPORT_SYMBOL(ilookup5); |
1260 | |
1261 | /** |
1262 | * ilookup - search for an inode in the inode cache |
1263 | * @sb: super block of file system to search |
1264 | * @ino: inode number to search for |
1265 | * |
1266 | * Search for the inode @ino in the inode cache, and if the inode is in the |
1267 | * cache, the inode is returned with an incremented reference count. |
1268 | */ |
1269 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1270 | { |
1271 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1272 | struct inode *inode; |
1273 | |
1274 | spin_lock(&inode_hash_lock); |
1275 | inode = find_inode_fast(sb, head, ino); |
1276 | spin_unlock(&inode_hash_lock); |
1277 | |
1278 | if (inode) |
1279 | wait_on_inode(inode); |
1280 | return inode; |
1281 | } |
1282 | EXPORT_SYMBOL(ilookup); |
1283 | |
1284 | int insert_inode_locked(struct inode *inode) |
1285 | { |
1286 | struct super_block *sb = inode->i_sb; |
1287 | ino_t ino = inode->i_ino; |
1288 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1289 | |
1290 | while (1) { |
1291 | struct inode *old = NULL; |
1292 | spin_lock(&inode_hash_lock); |
1293 | hlist_for_each_entry(old, head, i_hash) { |
1294 | if (old->i_ino != ino) |
1295 | continue; |
1296 | if (old->i_sb != sb) |
1297 | continue; |
1298 | spin_lock(&old->i_lock); |
1299 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1300 | spin_unlock(&old->i_lock); |
1301 | continue; |
1302 | } |
1303 | break; |
1304 | } |
1305 | if (likely(!old)) { |
1306 | spin_lock(&inode->i_lock); |
1307 | inode->i_state |= I_NEW; |
1308 | hlist_add_head(&inode->i_hash, head); |
1309 | spin_unlock(&inode->i_lock); |
1310 | spin_unlock(&inode_hash_lock); |
1311 | return 0; |
1312 | } |
1313 | __iget(old); |
1314 | spin_unlock(&old->i_lock); |
1315 | spin_unlock(&inode_hash_lock); |
1316 | wait_on_inode(old); |
1317 | if (unlikely(!inode_unhashed(old))) { |
1318 | iput(old); |
1319 | return -EBUSY; |
1320 | } |
1321 | iput(old); |
1322 | } |
1323 | } |
1324 | EXPORT_SYMBOL(insert_inode_locked); |
1325 | |
1326 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1327 | int (*test)(struct inode *, void *), void *data) |
1328 | { |
1329 | struct super_block *sb = inode->i_sb; |
1330 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1331 | |
1332 | while (1) { |
1333 | struct inode *old = NULL; |
1334 | |
1335 | spin_lock(&inode_hash_lock); |
1336 | hlist_for_each_entry(old, head, i_hash) { |
1337 | if (old->i_sb != sb) |
1338 | continue; |
1339 | if (!test(old, data)) |
1340 | continue; |
1341 | spin_lock(&old->i_lock); |
1342 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1343 | spin_unlock(&old->i_lock); |
1344 | continue; |
1345 | } |
1346 | break; |
1347 | } |
1348 | if (likely(!old)) { |
1349 | spin_lock(&inode->i_lock); |
1350 | inode->i_state |= I_NEW; |
1351 | hlist_add_head(&inode->i_hash, head); |
1352 | spin_unlock(&inode->i_lock); |
1353 | spin_unlock(&inode_hash_lock); |
1354 | return 0; |
1355 | } |
1356 | __iget(old); |
1357 | spin_unlock(&old->i_lock); |
1358 | spin_unlock(&inode_hash_lock); |
1359 | wait_on_inode(old); |
1360 | if (unlikely(!inode_unhashed(old))) { |
1361 | iput(old); |
1362 | return -EBUSY; |
1363 | } |
1364 | iput(old); |
1365 | } |
1366 | } |
1367 | EXPORT_SYMBOL(insert_inode_locked4); |
1368 | |
1369 | |
1370 | int generic_delete_inode(struct inode *inode) |
1371 | { |
1372 | return 1; |
1373 | } |
1374 | EXPORT_SYMBOL(generic_delete_inode); |
1375 | |
1376 | /* |
1377 | * Called when we're dropping the last reference |
1378 | * to an inode. |
1379 | * |
1380 | * Call the FS "drop_inode()" function, defaulting to |
1381 | * the legacy UNIX filesystem behaviour. If it tells |
1382 | * us to evict inode, do so. Otherwise, retain inode |
1383 | * in cache if fs is alive, sync and evict if fs is |
1384 | * shutting down. |
1385 | */ |
1386 | static void iput_final(struct inode *inode) |
1387 | { |
1388 | struct super_block *sb = inode->i_sb; |
1389 | const struct super_operations *op = inode->i_sb->s_op; |
1390 | int drop; |
1391 | |
1392 | WARN_ON(inode->i_state & I_NEW); |
1393 | |
1394 | if (op->drop_inode) |
1395 | drop = op->drop_inode(inode); |
1396 | else |
1397 | drop = generic_drop_inode(inode); |
1398 | |
1399 | if (!drop && (sb->s_flags & MS_ACTIVE)) { |
1400 | inode->i_state |= I_REFERENCED; |
1401 | inode_add_lru(inode); |
1402 | spin_unlock(&inode->i_lock); |
1403 | return; |
1404 | } |
1405 | |
1406 | if (!drop) { |
1407 | inode->i_state |= I_WILL_FREE; |
1408 | spin_unlock(&inode->i_lock); |
1409 | write_inode_now(inode, 1); |
1410 | spin_lock(&inode->i_lock); |
1411 | WARN_ON(inode->i_state & I_NEW); |
1412 | inode->i_state &= ~I_WILL_FREE; |
1413 | } |
1414 | |
1415 | inode->i_state |= I_FREEING; |
1416 | if (!list_empty(&inode->i_lru)) |
1417 | inode_lru_list_del(inode); |
1418 | spin_unlock(&inode->i_lock); |
1419 | |
1420 | evict(inode); |
1421 | } |
1422 | |
1423 | /** |
1424 | * iput - put an inode |
1425 | * @inode: inode to put |
1426 | * |
1427 | * Puts an inode, dropping its usage count. If the inode use count hits |
1428 | * zero, the inode is then freed and may also be destroyed. |
1429 | * |
1430 | * Consequently, iput() can sleep. |
1431 | */ |
1432 | void iput(struct inode *inode) |
1433 | { |
1434 | if (inode) { |
1435 | BUG_ON(inode->i_state & I_CLEAR); |
1436 | |
1437 | if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) |
1438 | iput_final(inode); |
1439 | } |
1440 | } |
1441 | EXPORT_SYMBOL(iput); |
1442 | |
1443 | /** |
1444 | * bmap - find a block number in a file |
1445 | * @inode: inode of file |
1446 | * @block: block to find |
1447 | * |
1448 | * Returns the block number on the device holding the inode that |
1449 | * is the disk block number for the block of the file requested. |
1450 | * That is, asked for block 4 of inode 1 the function will return the |
1451 | * disk block relative to the disk start that holds that block of the |
1452 | * file. |
1453 | */ |
1454 | sector_t bmap(struct inode *inode, sector_t block) |
1455 | { |
1456 | sector_t res = 0; |
1457 | if (inode->i_mapping->a_ops->bmap) |
1458 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
1459 | return res; |
1460 | } |
1461 | EXPORT_SYMBOL(bmap); |
1462 | |
1463 | /* |
1464 | * With relative atime, only update atime if the previous atime is |
1465 | * earlier than either the ctime or mtime or if at least a day has |
1466 | * passed since the last atime update. |
1467 | */ |
1468 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1469 | struct timespec now) |
1470 | { |
1471 | |
1472 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1473 | return 1; |
1474 | /* |
1475 | * Is mtime younger than atime? If yes, update atime: |
1476 | */ |
1477 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
1478 | return 1; |
1479 | /* |
1480 | * Is ctime younger than atime? If yes, update atime: |
1481 | */ |
1482 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
1483 | return 1; |
1484 | |
1485 | /* |
1486 | * Is the previous atime value older than a day? If yes, |
1487 | * update atime: |
1488 | */ |
1489 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
1490 | return 1; |
1491 | /* |
1492 | * Good, we can skip the atime update: |
1493 | */ |
1494 | return 0; |
1495 | } |
1496 | |
1497 | /* |
1498 | * This does the actual work of updating an inodes time or version. Must have |
1499 | * had called mnt_want_write() before calling this. |
1500 | */ |
1501 | static int update_time(struct inode *inode, struct timespec *time, int flags) |
1502 | { |
1503 | if (inode->i_op->update_time) |
1504 | return inode->i_op->update_time(inode, time, flags); |
1505 | |
1506 | if (flags & S_ATIME) |
1507 | inode->i_atime = *time; |
1508 | if (flags & S_VERSION) |
1509 | inode_inc_iversion(inode); |
1510 | if (flags & S_CTIME) |
1511 | inode->i_ctime = *time; |
1512 | if (flags & S_MTIME) |
1513 | inode->i_mtime = *time; |
1514 | mark_inode_dirty_sync(inode); |
1515 | return 0; |
1516 | } |
1517 | |
1518 | /** |
1519 | * touch_atime - update the access time |
1520 | * @path: the &struct path to update |
1521 | * |
1522 | * Update the accessed time on an inode and mark it for writeback. |
1523 | * This function automatically handles read only file systems and media, |
1524 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1525 | */ |
1526 | void touch_atime(struct path *path) |
1527 | { |
1528 | struct vfsmount *mnt = path->mnt; |
1529 | struct inode *inode = path->dentry->d_inode; |
1530 | struct timespec now; |
1531 | |
1532 | if (inode->i_flags & S_NOATIME) |
1533 | return; |
1534 | if (IS_NOATIME(inode)) |
1535 | return; |
1536 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1537 | return; |
1538 | |
1539 | if (mnt->mnt_flags & MNT_NOATIME) |
1540 | return; |
1541 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1542 | return; |
1543 | |
1544 | now = current_fs_time(inode->i_sb); |
1545 | |
1546 | if (!relatime_need_update(mnt, inode, now)) |
1547 | return; |
1548 | |
1549 | if (timespec_equal(&inode->i_atime, &now)) |
1550 | return; |
1551 | |
1552 | if (!sb_start_write_trylock(inode->i_sb)) |
1553 | return; |
1554 | |
1555 | if (__mnt_want_write(mnt)) |
1556 | goto skip_update; |
1557 | /* |
1558 | * File systems can error out when updating inodes if they need to |
1559 | * allocate new space to modify an inode (such is the case for |
1560 | * Btrfs), but since we touch atime while walking down the path we |
1561 | * really don't care if we failed to update the atime of the file, |
1562 | * so just ignore the return value. |
1563 | * We may also fail on filesystems that have the ability to make parts |
1564 | * of the fs read only, e.g. subvolumes in Btrfs. |
1565 | */ |
1566 | update_time(inode, &now, S_ATIME); |
1567 | __mnt_drop_write(mnt); |
1568 | skip_update: |
1569 | sb_end_write(inode->i_sb); |
1570 | } |
1571 | EXPORT_SYMBOL(touch_atime); |
1572 | |
1573 | /* |
1574 | * The logic we want is |
1575 | * |
1576 | * if suid or (sgid and xgrp) |
1577 | * remove privs |
1578 | */ |
1579 | int should_remove_suid(struct dentry *dentry) |
1580 | { |
1581 | umode_t mode = dentry->d_inode->i_mode; |
1582 | int kill = 0; |
1583 | |
1584 | /* suid always must be killed */ |
1585 | if (unlikely(mode & S_ISUID)) |
1586 | kill = ATTR_KILL_SUID; |
1587 | |
1588 | /* |
1589 | * sgid without any exec bits is just a mandatory locking mark; leave |
1590 | * it alone. If some exec bits are set, it's a real sgid; kill it. |
1591 | */ |
1592 | if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) |
1593 | kill |= ATTR_KILL_SGID; |
1594 | |
1595 | if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) |
1596 | return kill; |
1597 | |
1598 | return 0; |
1599 | } |
1600 | EXPORT_SYMBOL(should_remove_suid); |
1601 | |
1602 | static int __remove_suid(struct dentry *dentry, int kill) |
1603 | { |
1604 | struct iattr newattrs; |
1605 | |
1606 | newattrs.ia_valid = ATTR_FORCE | kill; |
1607 | return notify_change(dentry, &newattrs); |
1608 | } |
1609 | |
1610 | int file_remove_suid(struct file *file) |
1611 | { |
1612 | struct dentry *dentry = file->f_path.dentry; |
1613 | struct inode *inode = dentry->d_inode; |
1614 | int killsuid; |
1615 | int killpriv; |
1616 | int error = 0; |
1617 | |
1618 | /* Fast path for nothing security related */ |
1619 | if (IS_NOSEC(inode)) |
1620 | return 0; |
1621 | |
1622 | killsuid = should_remove_suid(dentry); |
1623 | killpriv = security_inode_need_killpriv(dentry); |
1624 | |
1625 | if (killpriv < 0) |
1626 | return killpriv; |
1627 | if (killpriv) |
1628 | error = security_inode_killpriv(dentry); |
1629 | if (!error && killsuid) |
1630 | error = __remove_suid(dentry, killsuid); |
1631 | if (!error && (inode->i_sb->s_flags & MS_NOSEC)) |
1632 | inode->i_flags |= S_NOSEC; |
1633 | |
1634 | return error; |
1635 | } |
1636 | EXPORT_SYMBOL(file_remove_suid); |
1637 | |
1638 | /** |
1639 | * file_update_time - update mtime and ctime time |
1640 | * @file: file accessed |
1641 | * |
1642 | * Update the mtime and ctime members of an inode and mark the inode |
1643 | * for writeback. Note that this function is meant exclusively for |
1644 | * usage in the file write path of filesystems, and filesystems may |
1645 | * choose to explicitly ignore update via this function with the |
1646 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
1647 | * timestamps are handled by the server. This can return an error for |
1648 | * file systems who need to allocate space in order to update an inode. |
1649 | */ |
1650 | |
1651 | int file_update_time(struct file *file) |
1652 | { |
1653 | struct inode *inode = file_inode(file); |
1654 | struct timespec now; |
1655 | int sync_it = 0; |
1656 | int ret; |
1657 | |
1658 | /* First try to exhaust all avenues to not sync */ |
1659 | if (IS_NOCMTIME(inode)) |
1660 | return 0; |
1661 | |
1662 | now = current_fs_time(inode->i_sb); |
1663 | if (!timespec_equal(&inode->i_mtime, &now)) |
1664 | sync_it = S_MTIME; |
1665 | |
1666 | if (!timespec_equal(&inode->i_ctime, &now)) |
1667 | sync_it |= S_CTIME; |
1668 | |
1669 | if (IS_I_VERSION(inode)) |
1670 | sync_it |= S_VERSION; |
1671 | |
1672 | if (!sync_it) |
1673 | return 0; |
1674 | |
1675 | /* Finally allowed to write? Takes lock. */ |
1676 | if (__mnt_want_write_file(file)) |
1677 | return 0; |
1678 | |
1679 | ret = update_time(inode, &now, sync_it); |
1680 | __mnt_drop_write_file(file); |
1681 | |
1682 | return ret; |
1683 | } |
1684 | EXPORT_SYMBOL(file_update_time); |
1685 | |
1686 | int inode_needs_sync(struct inode *inode) |
1687 | { |
1688 | if (IS_SYNC(inode)) |
1689 | return 1; |
1690 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
1691 | return 1; |
1692 | return 0; |
1693 | } |
1694 | EXPORT_SYMBOL(inode_needs_sync); |
1695 | |
1696 | int inode_wait(void *word) |
1697 | { |
1698 | schedule(); |
1699 | return 0; |
1700 | } |
1701 | EXPORT_SYMBOL(inode_wait); |
1702 | |
1703 | /* |
1704 | * If we try to find an inode in the inode hash while it is being |
1705 | * deleted, we have to wait until the filesystem completes its |
1706 | * deletion before reporting that it isn't found. This function waits |
1707 | * until the deletion _might_ have completed. Callers are responsible |
1708 | * to recheck inode state. |
1709 | * |
1710 | * It doesn't matter if I_NEW is not set initially, a call to |
1711 | * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
1712 | * will DTRT. |
1713 | */ |
1714 | static void __wait_on_freeing_inode(struct inode *inode) |
1715 | { |
1716 | wait_queue_head_t *wq; |
1717 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
1718 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
1719 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
1720 | spin_unlock(&inode->i_lock); |
1721 | spin_unlock(&inode_hash_lock); |
1722 | schedule(); |
1723 | finish_wait(wq, &wait.wait); |
1724 | spin_lock(&inode_hash_lock); |
1725 | } |
1726 | |
1727 | static __initdata unsigned long ihash_entries; |
1728 | static int __init set_ihash_entries(char *str) |
1729 | { |
1730 | if (!str) |
1731 | return 0; |
1732 | ihash_entries = simple_strtoul(str, &str, 0); |
1733 | return 1; |
1734 | } |
1735 | __setup("ihash_entries=", set_ihash_entries); |
1736 | |
1737 | /* |
1738 | * Initialize the waitqueues and inode hash table. |
1739 | */ |
1740 | void __init inode_init_early(void) |
1741 | { |
1742 | unsigned int loop; |
1743 | |
1744 | /* If hashes are distributed across NUMA nodes, defer |
1745 | * hash allocation until vmalloc space is available. |
1746 | */ |
1747 | if (hashdist) |
1748 | return; |
1749 | |
1750 | inode_hashtable = |
1751 | alloc_large_system_hash("Inode-cache", |
1752 | sizeof(struct hlist_head), |
1753 | ihash_entries, |
1754 | 14, |
1755 | HASH_EARLY, |
1756 | &i_hash_shift, |
1757 | &i_hash_mask, |
1758 | 0, |
1759 | 0); |
1760 | |
1761 | for (loop = 0; loop < (1U << i_hash_shift); loop++) |
1762 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1763 | } |
1764 | |
1765 | void __init inode_init(void) |
1766 | { |
1767 | unsigned int loop; |
1768 | |
1769 | /* inode slab cache */ |
1770 | inode_cachep = kmem_cache_create("inode_cache", |
1771 | sizeof(struct inode), |
1772 | 0, |
1773 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
1774 | SLAB_MEM_SPREAD), |
1775 | init_once); |
1776 | |
1777 | /* Hash may have been set up in inode_init_early */ |
1778 | if (!hashdist) |
1779 | return; |
1780 | |
1781 | inode_hashtable = |
1782 | alloc_large_system_hash("Inode-cache", |
1783 | sizeof(struct hlist_head), |
1784 | ihash_entries, |
1785 | 14, |
1786 | 0, |
1787 | &i_hash_shift, |
1788 | &i_hash_mask, |
1789 | 0, |
1790 | 0); |
1791 | |
1792 | for (loop = 0; loop < (1U << i_hash_shift); loop++) |
1793 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1794 | } |
1795 | |
1796 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
1797 | { |
1798 | inode->i_mode = mode; |
1799 | if (S_ISCHR(mode)) { |
1800 | inode->i_fop = &def_chr_fops; |
1801 | inode->i_rdev = rdev; |
1802 | } else if (S_ISBLK(mode)) { |
1803 | inode->i_fop = &def_blk_fops; |
1804 | inode->i_rdev = rdev; |
1805 | } else if (S_ISFIFO(mode)) |
1806 | inode->i_fop = &def_fifo_fops; |
1807 | else if (S_ISSOCK(mode)) |
1808 | inode->i_fop = &bad_sock_fops; |
1809 | else |
1810 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
1811 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
1812 | inode->i_ino); |
1813 | } |
1814 | EXPORT_SYMBOL(init_special_inode); |
1815 | |
1816 | /** |
1817 | * inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
1818 | * @inode: New inode |
1819 | * @dir: Directory inode |
1820 | * @mode: mode of the new inode |
1821 | */ |
1822 | void inode_init_owner(struct inode *inode, const struct inode *dir, |
1823 | umode_t mode) |
1824 | { |
1825 | inode->i_uid = current_fsuid(); |
1826 | if (dir && dir->i_mode & S_ISGID) { |
1827 | inode->i_gid = dir->i_gid; |
1828 | if (S_ISDIR(mode)) |
1829 | mode |= S_ISGID; |
1830 | } else |
1831 | inode->i_gid = current_fsgid(); |
1832 | inode->i_mode = mode; |
1833 | } |
1834 | EXPORT_SYMBOL(inode_init_owner); |
1835 | |
1836 | /** |
1837 | * inode_owner_or_capable - check current task permissions to inode |
1838 | * @inode: inode being checked |
1839 | * |
1840 | * Return true if current either has CAP_FOWNER to the inode, or |
1841 | * owns the file. |
1842 | */ |
1843 | bool inode_owner_or_capable(const struct inode *inode) |
1844 | { |
1845 | if (uid_eq(current_fsuid(), inode->i_uid)) |
1846 | return true; |
1847 | if (inode_capable(inode, CAP_FOWNER)) |
1848 | return true; |
1849 | return false; |
1850 | } |
1851 | EXPORT_SYMBOL(inode_owner_or_capable); |
1852 | |
1853 | /* |
1854 | * Direct i/o helper functions |
1855 | */ |
1856 | static void __inode_dio_wait(struct inode *inode) |
1857 | { |
1858 | wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP); |
1859 | DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); |
1860 | |
1861 | do { |
1862 | prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE); |
1863 | if (atomic_read(&inode->i_dio_count)) |
1864 | schedule(); |
1865 | } while (atomic_read(&inode->i_dio_count)); |
1866 | finish_wait(wq, &q.wait); |
1867 | } |
1868 | |
1869 | /** |
1870 | * inode_dio_wait - wait for outstanding DIO requests to finish |
1871 | * @inode: inode to wait for |
1872 | * |
1873 | * Waits for all pending direct I/O requests to finish so that we can |
1874 | * proceed with a truncate or equivalent operation. |
1875 | * |
1876 | * Must be called under a lock that serializes taking new references |
1877 | * to i_dio_count, usually by inode->i_mutex. |
1878 | */ |
1879 | void inode_dio_wait(struct inode *inode) |
1880 | { |
1881 | if (atomic_read(&inode->i_dio_count)) |
1882 | __inode_dio_wait(inode); |
1883 | } |
1884 | EXPORT_SYMBOL(inode_dio_wait); |
1885 | |
1886 | /* |
1887 | * inode_dio_done - signal finish of a direct I/O requests |
1888 | * @inode: inode the direct I/O happens on |
1889 | * |
1890 | * This is called once we've finished processing a direct I/O request, |
1891 | * and is used to wake up callers waiting for direct I/O to be quiesced. |
1892 | */ |
1893 | void inode_dio_done(struct inode *inode) |
1894 | { |
1895 | if (atomic_dec_and_test(&inode->i_dio_count)) |
1896 | wake_up_bit(&inode->i_state, __I_DIO_WAKEUP); |
1897 | } |
1898 | EXPORT_SYMBOL(inode_dio_done); |
1899 |
Branches:
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javiroman/ks7010
jz-2.6.34
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9