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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 <linux/list_lru.h> |
21 | #include "internal.h" |
22 | |
23 | /* |
24 | * Inode locking rules: |
25 | * |
26 | * inode->i_lock protects: |
27 | * inode->i_state, inode->i_hash, __iget() |
28 | * Inode LRU list locks protect: |
29 | * inode->i_sb->s_inode_lru, inode->i_lru |
30 | * inode_sb_list_lock protects: |
31 | * sb->s_inodes, inode->i_sb_list |
32 | * bdi->wb.list_lock protects: |
33 | * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list |
34 | * inode_hash_lock protects: |
35 | * inode_hashtable, inode->i_hash |
36 | * |
37 | * Lock ordering: |
38 | * |
39 | * inode_sb_list_lock |
40 | * inode->i_lock |
41 | * Inode LRU list locks |
42 | * |
43 | * bdi->wb.list_lock |
44 | * inode->i_lock |
45 | * |
46 | * inode_hash_lock |
47 | * inode_sb_list_lock |
48 | * inode->i_lock |
49 | * |
50 | * iunique_lock |
51 | * inode_hash_lock |
52 | */ |
53 | |
54 | static unsigned int i_hash_mask __read_mostly; |
55 | static unsigned int i_hash_shift __read_mostly; |
56 | static struct hlist_head *inode_hashtable __read_mostly; |
57 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
58 | |
59 | __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock); |
60 | |
61 | /* |
62 | * Empty aops. Can be used for the cases where the user does not |
63 | * define any of the address_space operations. |
64 | */ |
65 | const struct address_space_operations empty_aops = { |
66 | }; |
67 | EXPORT_SYMBOL(empty_aops); |
68 | |
69 | /* |
70 | * Statistics gathering.. |
71 | */ |
72 | struct inodes_stat_t inodes_stat; |
73 | |
74 | static DEFINE_PER_CPU(unsigned long, nr_inodes); |
75 | static DEFINE_PER_CPU(unsigned long, nr_unused); |
76 | |
77 | static struct kmem_cache *inode_cachep __read_mostly; |
78 | |
79 | static long get_nr_inodes(void) |
80 | { |
81 | int i; |
82 | long sum = 0; |
83 | for_each_possible_cpu(i) |
84 | sum += per_cpu(nr_inodes, i); |
85 | return sum < 0 ? 0 : sum; |
86 | } |
87 | |
88 | static inline long get_nr_inodes_unused(void) |
89 | { |
90 | int i; |
91 | long sum = 0; |
92 | for_each_possible_cpu(i) |
93 | sum += per_cpu(nr_unused, i); |
94 | return sum < 0 ? 0 : sum; |
95 | } |
96 | |
97 | long get_nr_dirty_inodes(void) |
98 | { |
99 | /* not actually dirty inodes, but a wild approximation */ |
100 | long nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
101 | return nr_dirty > 0 ? nr_dirty : 0; |
102 | } |
103 | |
104 | /* |
105 | * Handle nr_inode sysctl |
106 | */ |
107 | #ifdef CONFIG_SYSCTL |
108 | int proc_nr_inodes(struct ctl_table *table, int write, |
109 | void __user *buffer, size_t *lenp, loff_t *ppos) |
110 | { |
111 | inodes_stat.nr_inodes = get_nr_inodes(); |
112 | inodes_stat.nr_unused = get_nr_inodes_unused(); |
113 | return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); |
114 | } |
115 | #endif |
116 | |
117 | /** |
118 | * inode_init_always - perform inode structure intialisation |
119 | * @sb: superblock inode belongs to |
120 | * @inode: inode to initialise |
121 | * |
122 | * These are initializations that need to be done on every inode |
123 | * allocation as the fields are not initialised by slab allocation. |
124 | */ |
125 | int inode_init_always(struct super_block *sb, struct inode *inode) |
126 | { |
127 | static const struct inode_operations empty_iops; |
128 | static const struct file_operations empty_fops; |
129 | struct address_space *const mapping = &inode->i_data; |
130 | |
131 | inode->i_sb = sb; |
132 | inode->i_blkbits = sb->s_blocksize_bits; |
133 | inode->i_flags = 0; |
134 | atomic_set(&inode->i_count, 1); |
135 | inode->i_op = &empty_iops; |
136 | inode->i_fop = &empty_fops; |
137 | inode->__i_nlink = 1; |
138 | inode->i_opflags = 0; |
139 | i_uid_write(inode, 0); |
140 | i_gid_write(inode, 0); |
141 | atomic_set(&inode->i_writecount, 0); |
142 | inode->i_size = 0; |
143 | inode->i_blocks = 0; |
144 | inode->i_bytes = 0; |
145 | inode->i_generation = 0; |
146 | #ifdef CONFIG_QUOTA |
147 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); |
148 | #endif |
149 | inode->i_pipe = NULL; |
150 | inode->i_bdev = NULL; |
151 | inode->i_cdev = NULL; |
152 | inode->i_rdev = 0; |
153 | inode->dirtied_when = 0; |
154 | |
155 | if (security_inode_alloc(inode)) |
156 | goto out; |
157 | spin_lock_init(&inode->i_lock); |
158 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
159 | |
160 | mutex_init(&inode->i_mutex); |
161 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); |
162 | |
163 | atomic_set(&inode->i_dio_count, 0); |
164 | |
165 | mapping->a_ops = &empty_aops; |
166 | mapping->host = inode; |
167 | mapping->flags = 0; |
168 | atomic_set(&mapping->i_mmap_writable, 0); |
169 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE); |
170 | mapping->private_data = NULL; |
171 | mapping->backing_dev_info = &default_backing_dev_info; |
172 | mapping->writeback_index = 0; |
173 | |
174 | /* |
175 | * If the block_device provides a backing_dev_info for client |
176 | * inodes then use that. Otherwise the inode share the bdev's |
177 | * backing_dev_info. |
178 | */ |
179 | if (sb->s_bdev) { |
180 | struct backing_dev_info *bdi; |
181 | |
182 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; |
183 | mapping->backing_dev_info = bdi; |
184 | } |
185 | inode->i_private = NULL; |
186 | inode->i_mapping = mapping; |
187 | INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ |
188 | #ifdef CONFIG_FS_POSIX_ACL |
189 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
190 | #endif |
191 | |
192 | #ifdef CONFIG_FSNOTIFY |
193 | inode->i_fsnotify_mask = 0; |
194 | #endif |
195 | |
196 | this_cpu_inc(nr_inodes); |
197 | |
198 | return 0; |
199 | out: |
200 | return -ENOMEM; |
201 | } |
202 | EXPORT_SYMBOL(inode_init_always); |
203 | |
204 | static struct inode *alloc_inode(struct super_block *sb) |
205 | { |
206 | struct inode *inode; |
207 | |
208 | if (sb->s_op->alloc_inode) |
209 | inode = sb->s_op->alloc_inode(sb); |
210 | else |
211 | inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
212 | |
213 | if (!inode) |
214 | return NULL; |
215 | |
216 | if (unlikely(inode_init_always(sb, inode))) { |
217 | if (inode->i_sb->s_op->destroy_inode) |
218 | inode->i_sb->s_op->destroy_inode(inode); |
219 | else |
220 | kmem_cache_free(inode_cachep, inode); |
221 | return NULL; |
222 | } |
223 | |
224 | return inode; |
225 | } |
226 | |
227 | void free_inode_nonrcu(struct inode *inode) |
228 | { |
229 | kmem_cache_free(inode_cachep, inode); |
230 | } |
231 | EXPORT_SYMBOL(free_inode_nonrcu); |
232 | |
233 | void __destroy_inode(struct inode *inode) |
234 | { |
235 | BUG_ON(inode_has_buffers(inode)); |
236 | security_inode_free(inode); |
237 | fsnotify_inode_delete(inode); |
238 | if (!inode->i_nlink) { |
239 | WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); |
240 | atomic_long_dec(&inode->i_sb->s_remove_count); |
241 | } |
242 | |
243 | #ifdef CONFIG_FS_POSIX_ACL |
244 | if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED) |
245 | posix_acl_release(inode->i_acl); |
246 | if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED) |
247 | posix_acl_release(inode->i_default_acl); |
248 | #endif |
249 | this_cpu_dec(nr_inodes); |
250 | } |
251 | EXPORT_SYMBOL(__destroy_inode); |
252 | |
253 | static void i_callback(struct rcu_head *head) |
254 | { |
255 | struct inode *inode = container_of(head, struct inode, i_rcu); |
256 | kmem_cache_free(inode_cachep, inode); |
257 | } |
258 | |
259 | static void destroy_inode(struct inode *inode) |
260 | { |
261 | BUG_ON(!list_empty(&inode->i_lru)); |
262 | __destroy_inode(inode); |
263 | if (inode->i_sb->s_op->destroy_inode) |
264 | inode->i_sb->s_op->destroy_inode(inode); |
265 | else |
266 | call_rcu(&inode->i_rcu, i_callback); |
267 | } |
268 | |
269 | /** |
270 | * drop_nlink - directly drop an inode's link count |
271 | * @inode: inode |
272 | * |
273 | * This is a low-level filesystem helper to replace any |
274 | * direct filesystem manipulation of i_nlink. In cases |
275 | * where we are attempting to track writes to the |
276 | * filesystem, a decrement to zero means an imminent |
277 | * write when the file is truncated and actually unlinked |
278 | * on the filesystem. |
279 | */ |
280 | void drop_nlink(struct inode *inode) |
281 | { |
282 | WARN_ON(inode->i_nlink == 0); |
283 | inode->__i_nlink--; |
284 | if (!inode->i_nlink) |
285 | atomic_long_inc(&inode->i_sb->s_remove_count); |
286 | } |
287 | EXPORT_SYMBOL(drop_nlink); |
288 | |
289 | /** |
290 | * clear_nlink - directly zero an inode's link count |
291 | * @inode: inode |
292 | * |
293 | * This is a low-level filesystem helper to replace any |
294 | * direct filesystem manipulation of i_nlink. See |
295 | * drop_nlink() for why we care about i_nlink hitting zero. |
296 | */ |
297 | void clear_nlink(struct inode *inode) |
298 | { |
299 | if (inode->i_nlink) { |
300 | inode->__i_nlink = 0; |
301 | atomic_long_inc(&inode->i_sb->s_remove_count); |
302 | } |
303 | } |
304 | EXPORT_SYMBOL(clear_nlink); |
305 | |
306 | /** |
307 | * set_nlink - directly set an inode's link count |
308 | * @inode: inode |
309 | * @nlink: new nlink (should be non-zero) |
310 | * |
311 | * This is a low-level filesystem helper to replace any |
312 | * direct filesystem manipulation of i_nlink. |
313 | */ |
314 | void set_nlink(struct inode *inode, unsigned int nlink) |
315 | { |
316 | if (!nlink) { |
317 | clear_nlink(inode); |
318 | } else { |
319 | /* Yes, some filesystems do change nlink from zero to one */ |
320 | if (inode->i_nlink == 0) |
321 | atomic_long_dec(&inode->i_sb->s_remove_count); |
322 | |
323 | inode->__i_nlink = nlink; |
324 | } |
325 | } |
326 | EXPORT_SYMBOL(set_nlink); |
327 | |
328 | /** |
329 | * inc_nlink - directly increment an inode's link count |
330 | * @inode: inode |
331 | * |
332 | * This is a low-level filesystem helper to replace any |
333 | * direct filesystem manipulation of i_nlink. Currently, |
334 | * it is only here for parity with dec_nlink(). |
335 | */ |
336 | void inc_nlink(struct inode *inode) |
337 | { |
338 | if (unlikely(inode->i_nlink == 0)) { |
339 | WARN_ON(!(inode->i_state & I_LINKABLE)); |
340 | atomic_long_dec(&inode->i_sb->s_remove_count); |
341 | } |
342 | |
343 | inode->__i_nlink++; |
344 | } |
345 | EXPORT_SYMBOL(inc_nlink); |
346 | |
347 | void address_space_init_once(struct address_space *mapping) |
348 | { |
349 | memset(mapping, 0, sizeof(*mapping)); |
350 | INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC); |
351 | spin_lock_init(&mapping->tree_lock); |
352 | mutex_init(&mapping->i_mmap_mutex); |
353 | INIT_LIST_HEAD(&mapping->private_list); |
354 | spin_lock_init(&mapping->private_lock); |
355 | mapping->i_mmap = RB_ROOT; |
356 | INIT_LIST_HEAD(&mapping->i_mmap_nonlinear); |
357 | } |
358 | EXPORT_SYMBOL(address_space_init_once); |
359 | |
360 | /* |
361 | * These are initializations that only need to be done |
362 | * once, because the fields are idempotent across use |
363 | * of the inode, so let the slab aware of that. |
364 | */ |
365 | void inode_init_once(struct inode *inode) |
366 | { |
367 | memset(inode, 0, sizeof(*inode)); |
368 | INIT_HLIST_NODE(&inode->i_hash); |
369 | INIT_LIST_HEAD(&inode->i_devices); |
370 | INIT_LIST_HEAD(&inode->i_wb_list); |
371 | INIT_LIST_HEAD(&inode->i_lru); |
372 | address_space_init_once(&inode->i_data); |
373 | i_size_ordered_init(inode); |
374 | #ifdef CONFIG_FSNOTIFY |
375 | INIT_HLIST_HEAD(&inode->i_fsnotify_marks); |
376 | #endif |
377 | } |
378 | EXPORT_SYMBOL(inode_init_once); |
379 | |
380 | static void init_once(void *foo) |
381 | { |
382 | struct inode *inode = (struct inode *) foo; |
383 | |
384 | inode_init_once(inode); |
385 | } |
386 | |
387 | /* |
388 | * inode->i_lock must be held |
389 | */ |
390 | void __iget(struct inode *inode) |
391 | { |
392 | atomic_inc(&inode->i_count); |
393 | } |
394 | |
395 | /* |
396 | * get additional reference to inode; caller must already hold one. |
397 | */ |
398 | void ihold(struct inode *inode) |
399 | { |
400 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
401 | } |
402 | EXPORT_SYMBOL(ihold); |
403 | |
404 | static void inode_lru_list_add(struct inode *inode) |
405 | { |
406 | if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
407 | this_cpu_inc(nr_unused); |
408 | } |
409 | |
410 | /* |
411 | * Add inode to LRU if needed (inode is unused and clean). |
412 | * |
413 | * Needs inode->i_lock held. |
414 | */ |
415 | void inode_add_lru(struct inode *inode) |
416 | { |
417 | if (!(inode->i_state & (I_DIRTY | I_SYNC | I_FREEING | I_WILL_FREE)) && |
418 | !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE) |
419 | inode_lru_list_add(inode); |
420 | } |
421 | |
422 | |
423 | static void inode_lru_list_del(struct inode *inode) |
424 | { |
425 | |
426 | if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru)) |
427 | this_cpu_dec(nr_unused); |
428 | } |
429 | |
430 | /** |
431 | * inode_sb_list_add - add inode to the superblock list of inodes |
432 | * @inode: inode to add |
433 | */ |
434 | void inode_sb_list_add(struct inode *inode) |
435 | { |
436 | spin_lock(&inode_sb_list_lock); |
437 | list_add(&inode->i_sb_list, &inode->i_sb->s_inodes); |
438 | spin_unlock(&inode_sb_list_lock); |
439 | } |
440 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
441 | |
442 | static inline void inode_sb_list_del(struct inode *inode) |
443 | { |
444 | if (!list_empty(&inode->i_sb_list)) { |
445 | spin_lock(&inode_sb_list_lock); |
446 | list_del_init(&inode->i_sb_list); |
447 | spin_unlock(&inode_sb_list_lock); |
448 | } |
449 | } |
450 | |
451 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
452 | { |
453 | unsigned long tmp; |
454 | |
455 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
456 | L1_CACHE_BYTES; |
457 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
458 | return tmp & i_hash_mask; |
459 | } |
460 | |
461 | /** |
462 | * __insert_inode_hash - hash an inode |
463 | * @inode: unhashed inode |
464 | * @hashval: unsigned long value used to locate this object in the |
465 | * inode_hashtable. |
466 | * |
467 | * Add an inode to the inode hash for this superblock. |
468 | */ |
469 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
470 | { |
471 | struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval); |
472 | |
473 | spin_lock(&inode_hash_lock); |
474 | spin_lock(&inode->i_lock); |
475 | hlist_add_head(&inode->i_hash, b); |
476 | spin_unlock(&inode->i_lock); |
477 | spin_unlock(&inode_hash_lock); |
478 | } |
479 | EXPORT_SYMBOL(__insert_inode_hash); |
480 | |
481 | /** |
482 | * __remove_inode_hash - remove an inode from the hash |
483 | * @inode: inode to unhash |
484 | * |
485 | * Remove an inode from the superblock. |
486 | */ |
487 | void __remove_inode_hash(struct inode *inode) |
488 | { |
489 | spin_lock(&inode_hash_lock); |
490 | spin_lock(&inode->i_lock); |
491 | hlist_del_init(&inode->i_hash); |
492 | spin_unlock(&inode->i_lock); |
493 | spin_unlock(&inode_hash_lock); |
494 | } |
495 | EXPORT_SYMBOL(__remove_inode_hash); |
496 | |
497 | void clear_inode(struct inode *inode) |
498 | { |
499 | might_sleep(); |
500 | /* |
501 | * We have to cycle tree_lock here because reclaim can be still in the |
502 | * process of removing the last page (in __delete_from_page_cache()) |
503 | * and we must not free mapping under it. |
504 | */ |
505 | spin_lock_irq(&inode->i_data.tree_lock); |
506 | BUG_ON(inode->i_data.nrpages); |
507 | BUG_ON(inode->i_data.nrshadows); |
508 | spin_unlock_irq(&inode->i_data.tree_lock); |
509 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
510 | BUG_ON(!(inode->i_state & I_FREEING)); |
511 | BUG_ON(inode->i_state & I_CLEAR); |
512 | /* don't need i_lock here, no concurrent mods to i_state */ |
513 | inode->i_state = I_FREEING | I_CLEAR; |
514 | } |
515 | EXPORT_SYMBOL(clear_inode); |
516 | |
517 | /* |
518 | * Free the inode passed in, removing it from the lists it is still connected |
519 | * to. We remove any pages still attached to the inode and wait for any IO that |
520 | * is still in progress before finally destroying the inode. |
521 | * |
522 | * An inode must already be marked I_FREEING so that we avoid the inode being |
523 | * moved back onto lists if we race with other code that manipulates the lists |
524 | * (e.g. writeback_single_inode). The caller is responsible for setting this. |
525 | * |
526 | * An inode must already be removed from the LRU list before being evicted from |
527 | * the cache. This should occur atomically with setting the I_FREEING state |
528 | * flag, so no inodes here should ever be on the LRU when being evicted. |
529 | */ |
530 | static void evict(struct inode *inode) |
531 | { |
532 | const struct super_operations *op = inode->i_sb->s_op; |
533 | |
534 | BUG_ON(!(inode->i_state & I_FREEING)); |
535 | BUG_ON(!list_empty(&inode->i_lru)); |
536 | |
537 | if (!list_empty(&inode->i_wb_list)) |
538 | inode_wb_list_del(inode); |
539 | |
540 | inode_sb_list_del(inode); |
541 | |
542 | /* |
543 | * Wait for flusher thread to be done with the inode so that filesystem |
544 | * does not start destroying it while writeback is still running. Since |
545 | * the inode has I_FREEING set, flusher thread won't start new work on |
546 | * the inode. We just have to wait for running writeback to finish. |
547 | */ |
548 | inode_wait_for_writeback(inode); |
549 | |
550 | if (op->evict_inode) { |
551 | op->evict_inode(inode); |
552 | } else { |
553 | truncate_inode_pages_final(&inode->i_data); |
554 | clear_inode(inode); |
555 | } |
556 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
557 | bd_forget(inode); |
558 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
559 | cd_forget(inode); |
560 | |
561 | remove_inode_hash(inode); |
562 | |
563 | spin_lock(&inode->i_lock); |
564 | wake_up_bit(&inode->i_state, __I_NEW); |
565 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
566 | spin_unlock(&inode->i_lock); |
567 | |
568 | destroy_inode(inode); |
569 | } |
570 | |
571 | /* |
572 | * dispose_list - dispose of the contents of a local list |
573 | * @head: the head of the list to free |
574 | * |
575 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
576 | * need to worry about list corruption and SMP locks. |
577 | */ |
578 | static void dispose_list(struct list_head *head) |
579 | { |
580 | while (!list_empty(head)) { |
581 | struct inode *inode; |
582 | |
583 | inode = list_first_entry(head, struct inode, i_lru); |
584 | list_del_init(&inode->i_lru); |
585 | |
586 | evict(inode); |
587 | } |
588 | } |
589 | |
590 | /** |
591 | * evict_inodes - evict all evictable inodes for a superblock |
592 | * @sb: superblock to operate on |
593 | * |
594 | * Make sure that no inodes with zero refcount are retained. This is |
595 | * called by superblock shutdown after having MS_ACTIVE flag removed, |
596 | * so any inode reaching zero refcount during or after that call will |
597 | * be immediately evicted. |
598 | */ |
599 | void evict_inodes(struct super_block *sb) |
600 | { |
601 | struct inode *inode, *next; |
602 | LIST_HEAD(dispose); |
603 | |
604 | spin_lock(&inode_sb_list_lock); |
605 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
606 | if (atomic_read(&inode->i_count)) |
607 | continue; |
608 | |
609 | spin_lock(&inode->i_lock); |
610 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
611 | spin_unlock(&inode->i_lock); |
612 | continue; |
613 | } |
614 | |
615 | inode->i_state |= I_FREEING; |
616 | inode_lru_list_del(inode); |
617 | spin_unlock(&inode->i_lock); |
618 | list_add(&inode->i_lru, &dispose); |
619 | } |
620 | spin_unlock(&inode_sb_list_lock); |
621 | |
622 | dispose_list(&dispose); |
623 | } |
624 | |
625 | /** |
626 | * invalidate_inodes - attempt to free all inodes on a superblock |
627 | * @sb: superblock to operate on |
628 | * @kill_dirty: flag to guide handling of dirty inodes |
629 | * |
630 | * Attempts to free all inodes for a given superblock. If there were any |
631 | * busy inodes return a non-zero value, else zero. |
632 | * If @kill_dirty is set, discard dirty inodes too, otherwise treat |
633 | * them as busy. |
634 | */ |
635 | int invalidate_inodes(struct super_block *sb, bool kill_dirty) |
636 | { |
637 | int busy = 0; |
638 | struct inode *inode, *next; |
639 | LIST_HEAD(dispose); |
640 | |
641 | spin_lock(&inode_sb_list_lock); |
642 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
643 | spin_lock(&inode->i_lock); |
644 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
645 | spin_unlock(&inode->i_lock); |
646 | continue; |
647 | } |
648 | if (inode->i_state & I_DIRTY && !kill_dirty) { |
649 | spin_unlock(&inode->i_lock); |
650 | busy = 1; |
651 | continue; |
652 | } |
653 | if (atomic_read(&inode->i_count)) { |
654 | spin_unlock(&inode->i_lock); |
655 | busy = 1; |
656 | continue; |
657 | } |
658 | |
659 | inode->i_state |= I_FREEING; |
660 | inode_lru_list_del(inode); |
661 | spin_unlock(&inode->i_lock); |
662 | list_add(&inode->i_lru, &dispose); |
663 | } |
664 | spin_unlock(&inode_sb_list_lock); |
665 | |
666 | dispose_list(&dispose); |
667 | |
668 | return busy; |
669 | } |
670 | |
671 | /* |
672 | * Isolate the inode from the LRU in preparation for freeing it. |
673 | * |
674 | * Any inodes which are pinned purely because of attached pagecache have their |
675 | * pagecache removed. If the inode has metadata buffers attached to |
676 | * mapping->private_list then try to remove them. |
677 | * |
678 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
679 | * used recently - the flag is set in iput_final(). When we encounter such an |
680 | * inode, clear the flag and move it to the back of the LRU so it gets another |
681 | * pass through the LRU before it gets reclaimed. This is necessary because of |
682 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
683 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
684 | * with this flag set because they are the inodes that are out of order. |
685 | */ |
686 | static enum lru_status |
687 | inode_lru_isolate(struct list_head *item, spinlock_t *lru_lock, void *arg) |
688 | { |
689 | struct list_head *freeable = arg; |
690 | struct inode *inode = container_of(item, struct inode, i_lru); |
691 | |
692 | /* |
693 | * we are inverting the lru lock/inode->i_lock here, so use a trylock. |
694 | * If we fail to get the lock, just skip it. |
695 | */ |
696 | if (!spin_trylock(&inode->i_lock)) |
697 | return LRU_SKIP; |
698 | |
699 | /* |
700 | * Referenced or dirty inodes are still in use. Give them another pass |
701 | * through the LRU as we canot reclaim them now. |
702 | */ |
703 | if (atomic_read(&inode->i_count) || |
704 | (inode->i_state & ~I_REFERENCED)) { |
705 | list_del_init(&inode->i_lru); |
706 | spin_unlock(&inode->i_lock); |
707 | this_cpu_dec(nr_unused); |
708 | return LRU_REMOVED; |
709 | } |
710 | |
711 | /* recently referenced inodes get one more pass */ |
712 | if (inode->i_state & I_REFERENCED) { |
713 | inode->i_state &= ~I_REFERENCED; |
714 | spin_unlock(&inode->i_lock); |
715 | return LRU_ROTATE; |
716 | } |
717 | |
718 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { |
719 | __iget(inode); |
720 | spin_unlock(&inode->i_lock); |
721 | spin_unlock(lru_lock); |
722 | if (remove_inode_buffers(inode)) { |
723 | unsigned long reap; |
724 | reap = invalidate_mapping_pages(&inode->i_data, 0, -1); |
725 | if (current_is_kswapd()) |
726 | __count_vm_events(KSWAPD_INODESTEAL, reap); |
727 | else |
728 | __count_vm_events(PGINODESTEAL, reap); |
729 | if (current->reclaim_state) |
730 | current->reclaim_state->reclaimed_slab += reap; |
731 | } |
732 | iput(inode); |
733 | spin_lock(lru_lock); |
734 | return LRU_RETRY; |
735 | } |
736 | |
737 | WARN_ON(inode->i_state & I_NEW); |
738 | inode->i_state |= I_FREEING; |
739 | list_move(&inode->i_lru, freeable); |
740 | spin_unlock(&inode->i_lock); |
741 | |
742 | this_cpu_dec(nr_unused); |
743 | return LRU_REMOVED; |
744 | } |
745 | |
746 | /* |
747 | * Walk the superblock inode LRU for freeable inodes and attempt to free them. |
748 | * This is called from the superblock shrinker function with a number of inodes |
749 | * to trim from the LRU. Inodes to be freed are moved to a temporary list and |
750 | * then are freed outside inode_lock by dispose_list(). |
751 | */ |
752 | long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan, |
753 | int nid) |
754 | { |
755 | LIST_HEAD(freeable); |
756 | long freed; |
757 | |
758 | freed = list_lru_walk_node(&sb->s_inode_lru, nid, inode_lru_isolate, |
759 | &freeable, &nr_to_scan); |
760 | dispose_list(&freeable); |
761 | return freed; |
762 | } |
763 | |
764 | static void __wait_on_freeing_inode(struct inode *inode); |
765 | /* |
766 | * Called with the inode lock held. |
767 | */ |
768 | static struct inode *find_inode(struct super_block *sb, |
769 | struct hlist_head *head, |
770 | int (*test)(struct inode *, void *), |
771 | void *data) |
772 | { |
773 | struct inode *inode = NULL; |
774 | |
775 | repeat: |
776 | hlist_for_each_entry(inode, head, i_hash) { |
777 | if (inode->i_sb != sb) |
778 | continue; |
779 | if (!test(inode, data)) |
780 | continue; |
781 | spin_lock(&inode->i_lock); |
782 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
783 | __wait_on_freeing_inode(inode); |
784 | goto repeat; |
785 | } |
786 | __iget(inode); |
787 | spin_unlock(&inode->i_lock); |
788 | return inode; |
789 | } |
790 | return NULL; |
791 | } |
792 | |
793 | /* |
794 | * find_inode_fast is the fast path version of find_inode, see the comment at |
795 | * iget_locked for details. |
796 | */ |
797 | static struct inode *find_inode_fast(struct super_block *sb, |
798 | struct hlist_head *head, unsigned long ino) |
799 | { |
800 | struct inode *inode = NULL; |
801 | |
802 | repeat: |
803 | hlist_for_each_entry(inode, head, i_hash) { |
804 | if (inode->i_ino != ino) |
805 | continue; |
806 | if (inode->i_sb != sb) |
807 | continue; |
808 | spin_lock(&inode->i_lock); |
809 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
810 | __wait_on_freeing_inode(inode); |
811 | goto repeat; |
812 | } |
813 | __iget(inode); |
814 | spin_unlock(&inode->i_lock); |
815 | return inode; |
816 | } |
817 | return NULL; |
818 | } |
819 | |
820 | /* |
821 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
822 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
823 | * to renew the exhausted range. |
824 | * |
825 | * This does not significantly increase overflow rate because every CPU can |
826 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
827 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
828 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
829 | * overflow rate by 2x, which does not seem too significant. |
830 | * |
831 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
832 | * error if st_ino won't fit in target struct field. Use 32bit counter |
833 | * here to attempt to avoid that. |
834 | */ |
835 | #define LAST_INO_BATCH 1024 |
836 | static DEFINE_PER_CPU(unsigned int, last_ino); |
837 | |
838 | unsigned int get_next_ino(void) |
839 | { |
840 | unsigned int *p = &get_cpu_var(last_ino); |
841 | unsigned int res = *p; |
842 | |
843 | #ifdef CONFIG_SMP |
844 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
845 | static atomic_t shared_last_ino; |
846 | int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino); |
847 | |
848 | res = next - LAST_INO_BATCH; |
849 | } |
850 | #endif |
851 | |
852 | *p = ++res; |
853 | put_cpu_var(last_ino); |
854 | return res; |
855 | } |
856 | EXPORT_SYMBOL(get_next_ino); |
857 | |
858 | /** |
859 | * new_inode_pseudo - obtain an inode |
860 | * @sb: superblock |
861 | * |
862 | * Allocates a new inode for given superblock. |
863 | * Inode wont be chained in superblock s_inodes list |
864 | * This means : |
865 | * - fs can't be unmount |
866 | * - quotas, fsnotify, writeback can't work |
867 | */ |
868 | struct inode *new_inode_pseudo(struct super_block *sb) |
869 | { |
870 | struct inode *inode = alloc_inode(sb); |
871 | |
872 | if (inode) { |
873 | spin_lock(&inode->i_lock); |
874 | inode->i_state = 0; |
875 | spin_unlock(&inode->i_lock); |
876 | INIT_LIST_HEAD(&inode->i_sb_list); |
877 | } |
878 | return inode; |
879 | } |
880 | |
881 | /** |
882 | * new_inode - obtain an inode |
883 | * @sb: superblock |
884 | * |
885 | * Allocates a new inode for given superblock. The default gfp_mask |
886 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
887 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
888 | * for the page cache are not reclaimable or migratable, |
889 | * mapping_set_gfp_mask() must be called with suitable flags on the |
890 | * newly created inode's mapping |
891 | * |
892 | */ |
893 | struct inode *new_inode(struct super_block *sb) |
894 | { |
895 | struct inode *inode; |
896 | |
897 | spin_lock_prefetch(&inode_sb_list_lock); |
898 | |
899 | inode = new_inode_pseudo(sb); |
900 | if (inode) |
901 | inode_sb_list_add(inode); |
902 | return inode; |
903 | } |
904 | EXPORT_SYMBOL(new_inode); |
905 | |
906 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
907 | void lockdep_annotate_inode_mutex_key(struct inode *inode) |
908 | { |
909 | if (S_ISDIR(inode->i_mode)) { |
910 | struct file_system_type *type = inode->i_sb->s_type; |
911 | |
912 | /* Set new key only if filesystem hasn't already changed it */ |
913 | if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) { |
914 | /* |
915 | * ensure nobody is actually holding i_mutex |
916 | */ |
917 | mutex_destroy(&inode->i_mutex); |
918 | mutex_init(&inode->i_mutex); |
919 | lockdep_set_class(&inode->i_mutex, |
920 | &type->i_mutex_dir_key); |
921 | } |
922 | } |
923 | } |
924 | EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key); |
925 | #endif |
926 | |
927 | /** |
928 | * unlock_new_inode - clear the I_NEW state and wake up any waiters |
929 | * @inode: new inode to unlock |
930 | * |
931 | * Called when the inode is fully initialised to clear the new state of the |
932 | * inode and wake up anyone waiting for the inode to finish initialisation. |
933 | */ |
934 | void unlock_new_inode(struct inode *inode) |
935 | { |
936 | lockdep_annotate_inode_mutex_key(inode); |
937 | spin_lock(&inode->i_lock); |
938 | WARN_ON(!(inode->i_state & I_NEW)); |
939 | inode->i_state &= ~I_NEW; |
940 | smp_mb(); |
941 | wake_up_bit(&inode->i_state, __I_NEW); |
942 | spin_unlock(&inode->i_lock); |
943 | } |
944 | EXPORT_SYMBOL(unlock_new_inode); |
945 | |
946 | /** |
947 | * lock_two_nondirectories - take two i_mutexes on non-directory objects |
948 | * |
949 | * Lock any non-NULL argument that is not a directory. |
950 | * Zero, one or two objects may be locked by this function. |
951 | * |
952 | * @inode1: first inode to lock |
953 | * @inode2: second inode to lock |
954 | */ |
955 | void lock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
956 | { |
957 | if (inode1 > inode2) |
958 | swap(inode1, inode2); |
959 | |
960 | if (inode1 && !S_ISDIR(inode1->i_mode)) |
961 | mutex_lock(&inode1->i_mutex); |
962 | if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1) |
963 | mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2); |
964 | } |
965 | EXPORT_SYMBOL(lock_two_nondirectories); |
966 | |
967 | /** |
968 | * unlock_two_nondirectories - release locks from lock_two_nondirectories() |
969 | * @inode1: first inode to unlock |
970 | * @inode2: second inode to unlock |
971 | */ |
972 | void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
973 | { |
974 | if (inode1 && !S_ISDIR(inode1->i_mode)) |
975 | mutex_unlock(&inode1->i_mutex); |
976 | if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1) |
977 | mutex_unlock(&inode2->i_mutex); |
978 | } |
979 | EXPORT_SYMBOL(unlock_two_nondirectories); |
980 | |
981 | /** |
982 | * iget5_locked - obtain an inode from a mounted file system |
983 | * @sb: super block of file system |
984 | * @hashval: hash value (usually inode number) to get |
985 | * @test: callback used for comparisons between inodes |
986 | * @set: callback used to initialize a new struct inode |
987 | * @data: opaque data pointer to pass to @test and @set |
988 | * |
989 | * Search for the inode specified by @hashval and @data in the inode cache, |
990 | * and if present it is return it with an increased reference count. This is |
991 | * a generalized version of iget_locked() for file systems where the inode |
992 | * number is not sufficient for unique identification of an inode. |
993 | * |
994 | * If the inode is not in cache, allocate a new inode and return it locked, |
995 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
996 | * before unlocking it via unlock_new_inode(). |
997 | * |
998 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
999 | * sleep. |
1000 | */ |
1001 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
1002 | int (*test)(struct inode *, void *), |
1003 | int (*set)(struct inode *, void *), void *data) |
1004 | { |
1005 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1006 | struct inode *inode; |
1007 | |
1008 | spin_lock(&inode_hash_lock); |
1009 | inode = find_inode(sb, head, test, data); |
1010 | spin_unlock(&inode_hash_lock); |
1011 | |
1012 | if (inode) { |
1013 | wait_on_inode(inode); |
1014 | return inode; |
1015 | } |
1016 | |
1017 | inode = alloc_inode(sb); |
1018 | if (inode) { |
1019 | struct inode *old; |
1020 | |
1021 | spin_lock(&inode_hash_lock); |
1022 | /* We released the lock, so.. */ |
1023 | old = find_inode(sb, head, test, data); |
1024 | if (!old) { |
1025 | if (set(inode, data)) |
1026 | goto set_failed; |
1027 | |
1028 | spin_lock(&inode->i_lock); |
1029 | inode->i_state = I_NEW; |
1030 | hlist_add_head(&inode->i_hash, head); |
1031 | spin_unlock(&inode->i_lock); |
1032 | inode_sb_list_add(inode); |
1033 | spin_unlock(&inode_hash_lock); |
1034 | |
1035 | /* Return the locked inode with I_NEW set, the |
1036 | * caller is responsible for filling in the contents |
1037 | */ |
1038 | return inode; |
1039 | } |
1040 | |
1041 | /* |
1042 | * Uhhuh, somebody else created the same inode under |
1043 | * us. Use the old inode instead of the one we just |
1044 | * allocated. |
1045 | */ |
1046 | spin_unlock(&inode_hash_lock); |
1047 | destroy_inode(inode); |
1048 | inode = old; |
1049 | wait_on_inode(inode); |
1050 | } |
1051 | return inode; |
1052 | |
1053 | set_failed: |
1054 | spin_unlock(&inode_hash_lock); |
1055 | destroy_inode(inode); |
1056 | return NULL; |
1057 | } |
1058 | EXPORT_SYMBOL(iget5_locked); |
1059 | |
1060 | /** |
1061 | * iget_locked - obtain an inode from a mounted file system |
1062 | * @sb: super block of file system |
1063 | * @ino: inode number to get |
1064 | * |
1065 | * Search for the inode specified by @ino in the inode cache and if present |
1066 | * return it with an increased reference count. This is for file systems |
1067 | * where the inode number is sufficient for unique identification of an inode. |
1068 | * |
1069 | * If the inode is not in cache, allocate a new inode and return it locked, |
1070 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
1071 | * before unlocking it via unlock_new_inode(). |
1072 | */ |
1073 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1074 | { |
1075 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1076 | struct inode *inode; |
1077 | |
1078 | spin_lock(&inode_hash_lock); |
1079 | inode = find_inode_fast(sb, head, ino); |
1080 | spin_unlock(&inode_hash_lock); |
1081 | if (inode) { |
1082 | wait_on_inode(inode); |
1083 | return inode; |
1084 | } |
1085 | |
1086 | inode = alloc_inode(sb); |
1087 | if (inode) { |
1088 | struct inode *old; |
1089 | |
1090 | spin_lock(&inode_hash_lock); |
1091 | /* We released the lock, so.. */ |
1092 | old = find_inode_fast(sb, head, ino); |
1093 | if (!old) { |
1094 | inode->i_ino = ino; |
1095 | spin_lock(&inode->i_lock); |
1096 | inode->i_state = I_NEW; |
1097 | hlist_add_head(&inode->i_hash, head); |
1098 | spin_unlock(&inode->i_lock); |
1099 | inode_sb_list_add(inode); |
1100 | spin_unlock(&inode_hash_lock); |
1101 | |
1102 | /* Return the locked inode with I_NEW set, the |
1103 | * caller is responsible for filling in the contents |
1104 | */ |
1105 | return inode; |
1106 | } |
1107 | |
1108 | /* |
1109 | * Uhhuh, somebody else created the same inode under |
1110 | * us. Use the old inode instead of the one we just |
1111 | * allocated. |
1112 | */ |
1113 | spin_unlock(&inode_hash_lock); |
1114 | destroy_inode(inode); |
1115 | inode = old; |
1116 | wait_on_inode(inode); |
1117 | } |
1118 | return inode; |
1119 | } |
1120 | EXPORT_SYMBOL(iget_locked); |
1121 | |
1122 | /* |
1123 | * search the inode cache for a matching inode number. |
1124 | * If we find one, then the inode number we are trying to |
1125 | * allocate is not unique and so we should not use it. |
1126 | * |
1127 | * Returns 1 if the inode number is unique, 0 if it is not. |
1128 | */ |
1129 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
1130 | { |
1131 | struct hlist_head *b = inode_hashtable + hash(sb, ino); |
1132 | struct inode *inode; |
1133 | |
1134 | spin_lock(&inode_hash_lock); |
1135 | hlist_for_each_entry(inode, b, i_hash) { |
1136 | if (inode->i_ino == ino && inode->i_sb == sb) { |
1137 | spin_unlock(&inode_hash_lock); |
1138 | return 0; |
1139 | } |
1140 | } |
1141 | spin_unlock(&inode_hash_lock); |
1142 | |
1143 | return 1; |
1144 | } |
1145 | |
1146 | /** |
1147 | * iunique - get a unique inode number |
1148 | * @sb: superblock |
1149 | * @max_reserved: highest reserved inode number |
1150 | * |
1151 | * Obtain an inode number that is unique on the system for a given |
1152 | * superblock. This is used by file systems that have no natural |
1153 | * permanent inode numbering system. An inode number is returned that |
1154 | * is higher than the reserved limit but unique. |
1155 | * |
1156 | * BUGS: |
1157 | * With a large number of inodes live on the file system this function |
1158 | * currently becomes quite slow. |
1159 | */ |
1160 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
1161 | { |
1162 | /* |
1163 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
1164 | * error if st_ino won't fit in target struct field. Use 32bit counter |
1165 | * here to attempt to avoid that. |
1166 | */ |
1167 | static DEFINE_SPINLOCK(iunique_lock); |
1168 | static unsigned int counter; |
1169 | ino_t res; |
1170 | |
1171 | spin_lock(&iunique_lock); |
1172 | do { |
1173 | if (counter <= max_reserved) |
1174 | counter = max_reserved + 1; |
1175 | res = counter++; |
1176 | } while (!test_inode_iunique(sb, res)); |
1177 | spin_unlock(&iunique_lock); |
1178 | |
1179 | return res; |
1180 | } |
1181 | EXPORT_SYMBOL(iunique); |
1182 | |
1183 | struct inode *igrab(struct inode *inode) |
1184 | { |
1185 | spin_lock(&inode->i_lock); |
1186 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
1187 | __iget(inode); |
1188 | spin_unlock(&inode->i_lock); |
1189 | } else { |
1190 | spin_unlock(&inode->i_lock); |
1191 | /* |
1192 | * Handle the case where s_op->clear_inode is not been |
1193 | * called yet, and somebody is calling igrab |
1194 | * while the inode is getting freed. |
1195 | */ |
1196 | inode = NULL; |
1197 | } |
1198 | return inode; |
1199 | } |
1200 | EXPORT_SYMBOL(igrab); |
1201 | |
1202 | /** |
1203 | * ilookup5_nowait - search for an inode in the inode cache |
1204 | * @sb: super block of file system to search |
1205 | * @hashval: hash value (usually inode number) to search for |
1206 | * @test: callback used for comparisons between inodes |
1207 | * @data: opaque data pointer to pass to @test |
1208 | * |
1209 | * Search for the inode specified by @hashval and @data in the inode cache. |
1210 | * If the inode is in the cache, the inode is returned with an incremented |
1211 | * reference count. |
1212 | * |
1213 | * Note: I_NEW is not waited upon so you have to be very careful what you do |
1214 | * with the returned inode. You probably should be using ilookup5() instead. |
1215 | * |
1216 | * Note2: @test is called with the inode_hash_lock held, so can't sleep. |
1217 | */ |
1218 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
1219 | int (*test)(struct inode *, void *), void *data) |
1220 | { |
1221 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1222 | struct inode *inode; |
1223 | |
1224 | spin_lock(&inode_hash_lock); |
1225 | inode = find_inode(sb, head, test, data); |
1226 | spin_unlock(&inode_hash_lock); |
1227 | |
1228 | return inode; |
1229 | } |
1230 | EXPORT_SYMBOL(ilookup5_nowait); |
1231 | |
1232 | /** |
1233 | * ilookup5 - search for an inode in the inode cache |
1234 | * @sb: super block of file system to search |
1235 | * @hashval: hash value (usually inode number) to search for |
1236 | * @test: callback used for comparisons between inodes |
1237 | * @data: opaque data pointer to pass to @test |
1238 | * |
1239 | * Search for the inode specified by @hashval and @data in the inode cache, |
1240 | * and if the inode is in the cache, return the inode with an incremented |
1241 | * reference count. Waits on I_NEW before returning the inode. |
1242 | * returned with an incremented reference count. |
1243 | * |
1244 | * This is a generalized version of ilookup() for file systems where the |
1245 | * inode number is not sufficient for unique identification of an inode. |
1246 | * |
1247 | * Note: @test is called with the inode_hash_lock held, so can't sleep. |
1248 | */ |
1249 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
1250 | int (*test)(struct inode *, void *), void *data) |
1251 | { |
1252 | struct inode *inode = ilookup5_nowait(sb, hashval, test, data); |
1253 | |
1254 | if (inode) |
1255 | wait_on_inode(inode); |
1256 | return inode; |
1257 | } |
1258 | EXPORT_SYMBOL(ilookup5); |
1259 | |
1260 | /** |
1261 | * ilookup - search for an inode in the inode cache |
1262 | * @sb: super block of file system to search |
1263 | * @ino: inode number to search for |
1264 | * |
1265 | * Search for the inode @ino in the inode cache, and if the inode is in the |
1266 | * cache, the inode is returned with an incremented reference count. |
1267 | */ |
1268 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1269 | { |
1270 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1271 | struct inode *inode; |
1272 | |
1273 | spin_lock(&inode_hash_lock); |
1274 | inode = find_inode_fast(sb, head, ino); |
1275 | spin_unlock(&inode_hash_lock); |
1276 | |
1277 | if (inode) |
1278 | wait_on_inode(inode); |
1279 | return inode; |
1280 | } |
1281 | EXPORT_SYMBOL(ilookup); |
1282 | |
1283 | int insert_inode_locked(struct inode *inode) |
1284 | { |
1285 | struct super_block *sb = inode->i_sb; |
1286 | ino_t ino = inode->i_ino; |
1287 | struct hlist_head *head = inode_hashtable + hash(sb, ino); |
1288 | |
1289 | while (1) { |
1290 | struct inode *old = NULL; |
1291 | spin_lock(&inode_hash_lock); |
1292 | hlist_for_each_entry(old, head, i_hash) { |
1293 | if (old->i_ino != ino) |
1294 | continue; |
1295 | if (old->i_sb != sb) |
1296 | continue; |
1297 | spin_lock(&old->i_lock); |
1298 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1299 | spin_unlock(&old->i_lock); |
1300 | continue; |
1301 | } |
1302 | break; |
1303 | } |
1304 | if (likely(!old)) { |
1305 | spin_lock(&inode->i_lock); |
1306 | inode->i_state |= I_NEW; |
1307 | hlist_add_head(&inode->i_hash, head); |
1308 | spin_unlock(&inode->i_lock); |
1309 | spin_unlock(&inode_hash_lock); |
1310 | return 0; |
1311 | } |
1312 | __iget(old); |
1313 | spin_unlock(&old->i_lock); |
1314 | spin_unlock(&inode_hash_lock); |
1315 | wait_on_inode(old); |
1316 | if (unlikely(!inode_unhashed(old))) { |
1317 | iput(old); |
1318 | return -EBUSY; |
1319 | } |
1320 | iput(old); |
1321 | } |
1322 | } |
1323 | EXPORT_SYMBOL(insert_inode_locked); |
1324 | |
1325 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1326 | int (*test)(struct inode *, void *), void *data) |
1327 | { |
1328 | struct super_block *sb = inode->i_sb; |
1329 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1330 | |
1331 | while (1) { |
1332 | struct inode *old = NULL; |
1333 | |
1334 | spin_lock(&inode_hash_lock); |
1335 | hlist_for_each_entry(old, head, i_hash) { |
1336 | if (old->i_sb != sb) |
1337 | continue; |
1338 | if (!test(old, data)) |
1339 | continue; |
1340 | spin_lock(&old->i_lock); |
1341 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1342 | spin_unlock(&old->i_lock); |
1343 | continue; |
1344 | } |
1345 | break; |
1346 | } |
1347 | if (likely(!old)) { |
1348 | spin_lock(&inode->i_lock); |
1349 | inode->i_state |= I_NEW; |
1350 | hlist_add_head(&inode->i_hash, head); |
1351 | spin_unlock(&inode->i_lock); |
1352 | spin_unlock(&inode_hash_lock); |
1353 | return 0; |
1354 | } |
1355 | __iget(old); |
1356 | spin_unlock(&old->i_lock); |
1357 | spin_unlock(&inode_hash_lock); |
1358 | wait_on_inode(old); |
1359 | if (unlikely(!inode_unhashed(old))) { |
1360 | iput(old); |
1361 | return -EBUSY; |
1362 | } |
1363 | iput(old); |
1364 | } |
1365 | } |
1366 | EXPORT_SYMBOL(insert_inode_locked4); |
1367 | |
1368 | |
1369 | int generic_delete_inode(struct inode *inode) |
1370 | { |
1371 | return 1; |
1372 | } |
1373 | EXPORT_SYMBOL(generic_delete_inode); |
1374 | |
1375 | /* |
1376 | * Called when we're dropping the last reference |
1377 | * to an inode. |
1378 | * |
1379 | * Call the FS "drop_inode()" function, defaulting to |
1380 | * the legacy UNIX filesystem behaviour. If it tells |
1381 | * us to evict inode, do so. Otherwise, retain inode |
1382 | * in cache if fs is alive, sync and evict if fs is |
1383 | * shutting down. |
1384 | */ |
1385 | static void iput_final(struct inode *inode) |
1386 | { |
1387 | struct super_block *sb = inode->i_sb; |
1388 | const struct super_operations *op = inode->i_sb->s_op; |
1389 | int drop; |
1390 | |
1391 | WARN_ON(inode->i_state & I_NEW); |
1392 | |
1393 | if (op->drop_inode) |
1394 | drop = op->drop_inode(inode); |
1395 | else |
1396 | drop = generic_drop_inode(inode); |
1397 | |
1398 | if (!drop && (sb->s_flags & MS_ACTIVE)) { |
1399 | inode->i_state |= I_REFERENCED; |
1400 | inode_add_lru(inode); |
1401 | spin_unlock(&inode->i_lock); |
1402 | return; |
1403 | } |
1404 | |
1405 | if (!drop) { |
1406 | inode->i_state |= I_WILL_FREE; |
1407 | spin_unlock(&inode->i_lock); |
1408 | write_inode_now(inode, 1); |
1409 | spin_lock(&inode->i_lock); |
1410 | WARN_ON(inode->i_state & I_NEW); |
1411 | inode->i_state &= ~I_WILL_FREE; |
1412 | } |
1413 | |
1414 | inode->i_state |= I_FREEING; |
1415 | if (!list_empty(&inode->i_lru)) |
1416 | inode_lru_list_del(inode); |
1417 | spin_unlock(&inode->i_lock); |
1418 | |
1419 | evict(inode); |
1420 | } |
1421 | |
1422 | /** |
1423 | * iput - put an inode |
1424 | * @inode: inode to put |
1425 | * |
1426 | * Puts an inode, dropping its usage count. If the inode use count hits |
1427 | * zero, the inode is then freed and may also be destroyed. |
1428 | * |
1429 | * Consequently, iput() can sleep. |
1430 | */ |
1431 | void iput(struct inode *inode) |
1432 | { |
1433 | if (inode) { |
1434 | BUG_ON(inode->i_state & I_CLEAR); |
1435 | |
1436 | if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) |
1437 | iput_final(inode); |
1438 | } |
1439 | } |
1440 | EXPORT_SYMBOL(iput); |
1441 | |
1442 | /** |
1443 | * bmap - find a block number in a file |
1444 | * @inode: inode of file |
1445 | * @block: block to find |
1446 | * |
1447 | * Returns the block number on the device holding the inode that |
1448 | * is the disk block number for the block of the file requested. |
1449 | * That is, asked for block 4 of inode 1 the function will return the |
1450 | * disk block relative to the disk start that holds that block of the |
1451 | * file. |
1452 | */ |
1453 | sector_t bmap(struct inode *inode, sector_t block) |
1454 | { |
1455 | sector_t res = 0; |
1456 | if (inode->i_mapping->a_ops->bmap) |
1457 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); |
1458 | return res; |
1459 | } |
1460 | EXPORT_SYMBOL(bmap); |
1461 | |
1462 | /* |
1463 | * With relative atime, only update atime if the previous atime is |
1464 | * earlier than either the ctime or mtime or if at least a day has |
1465 | * passed since the last atime update. |
1466 | */ |
1467 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1468 | struct timespec now) |
1469 | { |
1470 | |
1471 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1472 | return 1; |
1473 | /* |
1474 | * Is mtime younger than atime? If yes, update atime: |
1475 | */ |
1476 | if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0) |
1477 | return 1; |
1478 | /* |
1479 | * Is ctime younger than atime? If yes, update atime: |
1480 | */ |
1481 | if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0) |
1482 | return 1; |
1483 | |
1484 | /* |
1485 | * Is the previous atime value older than a day? If yes, |
1486 | * update atime: |
1487 | */ |
1488 | if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60) |
1489 | return 1; |
1490 | /* |
1491 | * Good, we can skip the atime update: |
1492 | */ |
1493 | return 0; |
1494 | } |
1495 | |
1496 | /* |
1497 | * This does the actual work of updating an inodes time or version. Must have |
1498 | * had called mnt_want_write() before calling this. |
1499 | */ |
1500 | static int update_time(struct inode *inode, struct timespec *time, int flags) |
1501 | { |
1502 | if (inode->i_op->update_time) |
1503 | return inode->i_op->update_time(inode, time, flags); |
1504 | |
1505 | if (flags & S_ATIME) |
1506 | inode->i_atime = *time; |
1507 | if (flags & S_VERSION) |
1508 | inode_inc_iversion(inode); |
1509 | if (flags & S_CTIME) |
1510 | inode->i_ctime = *time; |
1511 | if (flags & S_MTIME) |
1512 | inode->i_mtime = *time; |
1513 | mark_inode_dirty_sync(inode); |
1514 | return 0; |
1515 | } |
1516 | |
1517 | /** |
1518 | * touch_atime - update the access time |
1519 | * @path: the &struct path to update |
1520 | * |
1521 | * Update the accessed time on an inode and mark it for writeback. |
1522 | * This function automatically handles read only file systems and media, |
1523 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1524 | */ |
1525 | void touch_atime(const struct path *path) |
1526 | { |
1527 | struct vfsmount *mnt = path->mnt; |
1528 | struct inode *inode = path->dentry->d_inode; |
1529 | struct timespec now; |
1530 | |
1531 | if (inode->i_flags & S_NOATIME) |
1532 | return; |
1533 | if (IS_NOATIME(inode)) |
1534 | return; |
1535 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1536 | return; |
1537 | |
1538 | if (mnt->mnt_flags & MNT_NOATIME) |
1539 | return; |
1540 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1541 | return; |
1542 | |
1543 | now = current_fs_time(inode->i_sb); |
1544 | |
1545 | if (!relatime_need_update(mnt, inode, now)) |
1546 | return; |
1547 | |
1548 | if (timespec_equal(&inode->i_atime, &now)) |
1549 | return; |
1550 | |
1551 | if (!sb_start_write_trylock(inode->i_sb)) |
1552 | return; |
1553 | |
1554 | if (__mnt_want_write(mnt)) |
1555 | goto skip_update; |
1556 | /* |
1557 | * File systems can error out when updating inodes if they need to |
1558 | * allocate new space to modify an inode (such is the case for |
1559 | * Btrfs), but since we touch atime while walking down the path we |
1560 | * really don't care if we failed to update the atime of the file, |
1561 | * so just ignore the return value. |
1562 | * We may also fail on filesystems that have the ability to make parts |
1563 | * of the fs read only, e.g. subvolumes in Btrfs. |
1564 | */ |
1565 | update_time(inode, &now, S_ATIME); |
1566 | __mnt_drop_write(mnt); |
1567 | skip_update: |
1568 | sb_end_write(inode->i_sb); |
1569 | } |
1570 | EXPORT_SYMBOL(touch_atime); |
1571 | |
1572 | /* |
1573 | * The logic we want is |
1574 | * |
1575 | * if suid or (sgid and xgrp) |
1576 | * remove privs |
1577 | */ |
1578 | int should_remove_suid(struct dentry *dentry) |
1579 | { |
1580 | umode_t mode = dentry->d_inode->i_mode; |
1581 | int kill = 0; |
1582 | |
1583 | /* suid always must be killed */ |
1584 | if (unlikely(mode & S_ISUID)) |
1585 | kill = ATTR_KILL_SUID; |
1586 | |
1587 | /* |
1588 | * sgid without any exec bits is just a mandatory locking mark; leave |
1589 | * it alone. If some exec bits are set, it's a real sgid; kill it. |
1590 | */ |
1591 | if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) |
1592 | kill |= ATTR_KILL_SGID; |
1593 | |
1594 | if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) |
1595 | return kill; |
1596 | |
1597 | return 0; |
1598 | } |
1599 | EXPORT_SYMBOL(should_remove_suid); |
1600 | |
1601 | static int __remove_suid(struct dentry *dentry, int kill) |
1602 | { |
1603 | struct iattr newattrs; |
1604 | |
1605 | newattrs.ia_valid = ATTR_FORCE | kill; |
1606 | /* |
1607 | * Note we call this on write, so notify_change will not |
1608 | * encounter any conflicting delegations: |
1609 | */ |
1610 | return notify_change(dentry, &newattrs, NULL); |
1611 | } |
1612 | |
1613 | int file_remove_suid(struct file *file) |
1614 | { |
1615 | struct dentry *dentry = file->f_path.dentry; |
1616 | struct inode *inode = dentry->d_inode; |
1617 | int killsuid; |
1618 | int killpriv; |
1619 | int error = 0; |
1620 | |
1621 | /* Fast path for nothing security related */ |
1622 | if (IS_NOSEC(inode)) |
1623 | return 0; |
1624 | |
1625 | killsuid = should_remove_suid(dentry); |
1626 | killpriv = security_inode_need_killpriv(dentry); |
1627 | |
1628 | if (killpriv < 0) |
1629 | return killpriv; |
1630 | if (killpriv) |
1631 | error = security_inode_killpriv(dentry); |
1632 | if (!error && killsuid) |
1633 | error = __remove_suid(dentry, killsuid); |
1634 | if (!error && (inode->i_sb->s_flags & MS_NOSEC)) |
1635 | inode->i_flags |= S_NOSEC; |
1636 | |
1637 | return error; |
1638 | } |
1639 | EXPORT_SYMBOL(file_remove_suid); |
1640 | |
1641 | /** |
1642 | * file_update_time - update mtime and ctime time |
1643 | * @file: file accessed |
1644 | * |
1645 | * Update the mtime and ctime members of an inode and mark the inode |
1646 | * for writeback. Note that this function is meant exclusively for |
1647 | * usage in the file write path of filesystems, and filesystems may |
1648 | * choose to explicitly ignore update via this function with the |
1649 | * S_NOCMTIME inode flag, e.g. for network filesystem where these |
1650 | * timestamps are handled by the server. This can return an error for |
1651 | * file systems who need to allocate space in order to update an inode. |
1652 | */ |
1653 | |
1654 | int file_update_time(struct file *file) |
1655 | { |
1656 | struct inode *inode = file_inode(file); |
1657 | struct timespec now; |
1658 | int sync_it = 0; |
1659 | int ret; |
1660 | |
1661 | /* First try to exhaust all avenues to not sync */ |
1662 | if (IS_NOCMTIME(inode)) |
1663 | return 0; |
1664 | |
1665 | now = current_fs_time(inode->i_sb); |
1666 | if (!timespec_equal(&inode->i_mtime, &now)) |
1667 | sync_it = S_MTIME; |
1668 | |
1669 | if (!timespec_equal(&inode->i_ctime, &now)) |
1670 | sync_it |= S_CTIME; |
1671 | |
1672 | if (IS_I_VERSION(inode)) |
1673 | sync_it |= S_VERSION; |
1674 | |
1675 | if (!sync_it) |
1676 | return 0; |
1677 | |
1678 | /* Finally allowed to write? Takes lock. */ |
1679 | if (__mnt_want_write_file(file)) |
1680 | return 0; |
1681 | |
1682 | ret = update_time(inode, &now, sync_it); |
1683 | __mnt_drop_write_file(file); |
1684 | |
1685 | return ret; |
1686 | } |
1687 | EXPORT_SYMBOL(file_update_time); |
1688 | |
1689 | int inode_needs_sync(struct inode *inode) |
1690 | { |
1691 | if (IS_SYNC(inode)) |
1692 | return 1; |
1693 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
1694 | return 1; |
1695 | return 0; |
1696 | } |
1697 | EXPORT_SYMBOL(inode_needs_sync); |
1698 | |
1699 | /* |
1700 | * If we try to find an inode in the inode hash while it is being |
1701 | * deleted, we have to wait until the filesystem completes its |
1702 | * deletion before reporting that it isn't found. This function waits |
1703 | * until the deletion _might_ have completed. Callers are responsible |
1704 | * to recheck inode state. |
1705 | * |
1706 | * It doesn't matter if I_NEW is not set initially, a call to |
1707 | * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
1708 | * will DTRT. |
1709 | */ |
1710 | static void __wait_on_freeing_inode(struct inode *inode) |
1711 | { |
1712 | wait_queue_head_t *wq; |
1713 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
1714 | wq = bit_waitqueue(&inode->i_state, __I_NEW); |
1715 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); |
1716 | spin_unlock(&inode->i_lock); |
1717 | spin_unlock(&inode_hash_lock); |
1718 | schedule(); |
1719 | finish_wait(wq, &wait.wait); |
1720 | spin_lock(&inode_hash_lock); |
1721 | } |
1722 | |
1723 | static __initdata unsigned long ihash_entries; |
1724 | static int __init set_ihash_entries(char *str) |
1725 | { |
1726 | if (!str) |
1727 | return 0; |
1728 | ihash_entries = simple_strtoul(str, &str, 0); |
1729 | return 1; |
1730 | } |
1731 | __setup("ihash_entries=", set_ihash_entries); |
1732 | |
1733 | /* |
1734 | * Initialize the waitqueues and inode hash table. |
1735 | */ |
1736 | void __init inode_init_early(void) |
1737 | { |
1738 | unsigned int loop; |
1739 | |
1740 | /* If hashes are distributed across NUMA nodes, defer |
1741 | * hash allocation until vmalloc space is available. |
1742 | */ |
1743 | if (hashdist) |
1744 | return; |
1745 | |
1746 | inode_hashtable = |
1747 | alloc_large_system_hash("Inode-cache", |
1748 | sizeof(struct hlist_head), |
1749 | ihash_entries, |
1750 | 14, |
1751 | HASH_EARLY, |
1752 | &i_hash_shift, |
1753 | &i_hash_mask, |
1754 | 0, |
1755 | 0); |
1756 | |
1757 | for (loop = 0; loop < (1U << i_hash_shift); loop++) |
1758 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1759 | } |
1760 | |
1761 | void __init inode_init(void) |
1762 | { |
1763 | unsigned int loop; |
1764 | |
1765 | /* inode slab cache */ |
1766 | inode_cachep = kmem_cache_create("inode_cache", |
1767 | sizeof(struct inode), |
1768 | 0, |
1769 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
1770 | SLAB_MEM_SPREAD), |
1771 | init_once); |
1772 | |
1773 | /* Hash may have been set up in inode_init_early */ |
1774 | if (!hashdist) |
1775 | return; |
1776 | |
1777 | inode_hashtable = |
1778 | alloc_large_system_hash("Inode-cache", |
1779 | sizeof(struct hlist_head), |
1780 | ihash_entries, |
1781 | 14, |
1782 | 0, |
1783 | &i_hash_shift, |
1784 | &i_hash_mask, |
1785 | 0, |
1786 | 0); |
1787 | |
1788 | for (loop = 0; loop < (1U << i_hash_shift); loop++) |
1789 | INIT_HLIST_HEAD(&inode_hashtable[loop]); |
1790 | } |
1791 | |
1792 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
1793 | { |
1794 | inode->i_mode = mode; |
1795 | if (S_ISCHR(mode)) { |
1796 | inode->i_fop = &def_chr_fops; |
1797 | inode->i_rdev = rdev; |
1798 | } else if (S_ISBLK(mode)) { |
1799 | inode->i_fop = &def_blk_fops; |
1800 | inode->i_rdev = rdev; |
1801 | } else if (S_ISFIFO(mode)) |
1802 | inode->i_fop = &pipefifo_fops; |
1803 | else if (S_ISSOCK(mode)) |
1804 | inode->i_fop = &bad_sock_fops; |
1805 | else |
1806 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
1807 | " inode %s:%lu\n", mode, inode->i_sb->s_id, |
1808 | inode->i_ino); |
1809 | } |
1810 | EXPORT_SYMBOL(init_special_inode); |
1811 | |
1812 | /** |
1813 | * inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
1814 | * @inode: New inode |
1815 | * @dir: Directory inode |
1816 | * @mode: mode of the new inode |
1817 | */ |
1818 | void inode_init_owner(struct inode *inode, const struct inode *dir, |
1819 | umode_t mode) |
1820 | { |
1821 | inode->i_uid = current_fsuid(); |
1822 | if (dir && dir->i_mode & S_ISGID) { |
1823 | inode->i_gid = dir->i_gid; |
1824 | if (S_ISDIR(mode)) |
1825 | mode |= S_ISGID; |
1826 | } else |
1827 | inode->i_gid = current_fsgid(); |
1828 | inode->i_mode = mode; |
1829 | } |
1830 | EXPORT_SYMBOL(inode_init_owner); |
1831 | |
1832 | /** |
1833 | * inode_owner_or_capable - check current task permissions to inode |
1834 | * @inode: inode being checked |
1835 | * |
1836 | * Return true if current either has CAP_FOWNER in a namespace with the |
1837 | * inode owner uid mapped, or owns the file. |
1838 | */ |
1839 | bool inode_owner_or_capable(const struct inode *inode) |
1840 | { |
1841 | struct user_namespace *ns; |
1842 | |
1843 | if (uid_eq(current_fsuid(), inode->i_uid)) |
1844 | return true; |
1845 | |
1846 | ns = current_user_ns(); |
1847 | if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) |
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 | |
1900 | /* |
1901 | * inode_set_flags - atomically set some inode flags |
1902 | * |
1903 | * Note: the caller should be holding i_mutex, or else be sure that |
1904 | * they have exclusive access to the inode structure (i.e., while the |
1905 | * inode is being instantiated). The reason for the cmpxchg() loop |
1906 | * --- which wouldn't be necessary if all code paths which modify |
1907 | * i_flags actually followed this rule, is that there is at least one |
1908 | * code path which doesn't today --- for example, |
1909 | * __generic_file_aio_write() calls file_remove_suid() without holding |
1910 | * i_mutex --- so we use cmpxchg() out of an abundance of caution. |
1911 | * |
1912 | * In the long run, i_mutex is overkill, and we should probably look |
1913 | * at using the i_lock spinlock to protect i_flags, and then make sure |
1914 | * it is so documented in include/linux/fs.h and that all code follows |
1915 | * the locking convention!! |
1916 | */ |
1917 | void inode_set_flags(struct inode *inode, unsigned int flags, |
1918 | unsigned int mask) |
1919 | { |
1920 | unsigned int old_flags, new_flags; |
1921 | |
1922 | WARN_ON_ONCE(flags & ~mask); |
1923 | do { |
1924 | old_flags = ACCESS_ONCE(inode->i_flags); |
1925 | new_flags = (old_flags & ~mask) | flags; |
1926 | } while (unlikely(cmpxchg(&inode->i_flags, old_flags, |
1927 | new_flags) != old_flags)); |
1928 | } |
1929 | EXPORT_SYMBOL(inode_set_flags); |
1930 |
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