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1/*
2 * (C) 1997 Linus Torvalds
3 * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation)
4 */
5#include <linux/fs.h>
6#include <linux/mm.h>
7#include <linux/dcache.h>
8#include <linux/init.h>
9#include <linux/slab.h>
10#include <linux/writeback.h>
11#include <linux/module.h>
12#include <linux/backing-dev.h>
13#include <linux/wait.h>
14#include <linux/rwsem.h>
15#include <linux/hash.h>
16#include <linux/swap.h>
17#include <linux/security.h>
18#include <linux/pagemap.h>
19#include <linux/cdev.h>
20#include <linux/bootmem.h>
21#include <linux/fsnotify.h>
22#include <linux/mount.h>
23#include <linux/async.h>
24#include <linux/posix_acl.h>
25#include <linux/prefetch.h>
26#include <linux/ima.h>
27#include <linux/cred.h>
28#include <linux/buffer_head.h> /* for inode_has_buffers */
29#include "internal.h"
30
31/*
32 * Inode locking rules:
33 *
34 * inode->i_lock protects:
35 * inode->i_state, inode->i_hash, __iget()
36 * inode->i_sb->s_inode_lru_lock protects:
37 * inode->i_sb->s_inode_lru, inode->i_lru
38 * inode_sb_list_lock protects:
39 * sb->s_inodes, inode->i_sb_list
40 * bdi->wb.list_lock protects:
41 * bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list
42 * inode_hash_lock protects:
43 * inode_hashtable, inode->i_hash
44 *
45 * Lock ordering:
46 *
47 * inode_sb_list_lock
48 * inode->i_lock
49 * inode->i_sb->s_inode_lru_lock
50 *
51 * bdi->wb.list_lock
52 * inode->i_lock
53 *
54 * inode_hash_lock
55 * inode_sb_list_lock
56 * inode->i_lock
57 *
58 * iunique_lock
59 * inode_hash_lock
60 */
61
62static unsigned int i_hash_mask __read_mostly;
63static unsigned int i_hash_shift __read_mostly;
64static struct hlist_head *inode_hashtable __read_mostly;
65static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
66
67__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);
68
69/*
70 * Empty aops. Can be used for the cases where the user does not
71 * define any of the address_space operations.
72 */
73const struct address_space_operations empty_aops = {
74};
75EXPORT_SYMBOL(empty_aops);
76
77/*
78 * Statistics gathering..
79 */
80struct inodes_stat_t inodes_stat;
81
82static DEFINE_PER_CPU(unsigned int, nr_inodes);
83static DEFINE_PER_CPU(unsigned int, nr_unused);
84
85static struct kmem_cache *inode_cachep __read_mostly;
86
87static int get_nr_inodes(void)
88{
89 int i;
90 int sum = 0;
91 for_each_possible_cpu(i)
92 sum += per_cpu(nr_inodes, i);
93 return sum < 0 ? 0 : sum;
94}
95
96static inline int get_nr_inodes_unused(void)
97{
98 int i;
99 int sum = 0;
100 for_each_possible_cpu(i)
101 sum += per_cpu(nr_unused, i);
102 return sum < 0 ? 0 : sum;
103}
104
105int get_nr_dirty_inodes(void)
106{
107 /* not actually dirty inodes, but a wild approximation */
108 int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
109 return nr_dirty > 0 ? nr_dirty : 0;
110}
111
112/*
113 * Handle nr_inode sysctl
114 */
115#ifdef CONFIG_SYSCTL
116int proc_nr_inodes(ctl_table *table, int write,
117 void __user *buffer, size_t *lenp, loff_t *ppos)
118{
119 inodes_stat.nr_inodes = get_nr_inodes();
120 inodes_stat.nr_unused = get_nr_inodes_unused();
121 return proc_dointvec(table, write, buffer, lenp, ppos);
122}
123#endif
124
125/**
126 * inode_init_always - perform inode structure intialisation
127 * @sb: superblock inode belongs to
128 * @inode: inode to initialise
129 *
130 * These are initializations that need to be done on every inode
131 * allocation as the fields are not initialised by slab allocation.
132 */
133int inode_init_always(struct super_block *sb, struct inode *inode)
134{
135 static const struct inode_operations empty_iops;
136 static const struct file_operations empty_fops;
137 struct address_space *const mapping = &inode->i_data;
138
139 inode->i_sb = sb;
140 inode->i_blkbits = sb->s_blocksize_bits;
141 inode->i_flags = 0;
142 atomic_set(&inode->i_count, 1);
143 inode->i_op = &empty_iops;
144 inode->i_fop = &empty_fops;
145 inode->i_nlink = 1;
146 inode->i_opflags = 0;
147 inode->i_uid = 0;
148 inode->i_gid = 0;
149 atomic_set(&inode->i_writecount, 0);
150 inode->i_size = 0;
151 inode->i_blocks = 0;
152 inode->i_bytes = 0;
153 inode->i_generation = 0;
154#ifdef CONFIG_QUOTA
155 memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
156#endif
157 inode->i_pipe = NULL;
158 inode->i_bdev = NULL;
159 inode->i_cdev = NULL;
160 inode->i_rdev = 0;
161 inode->dirtied_when = 0;
162
163 if (security_inode_alloc(inode))
164 goto out;
165 spin_lock_init(&inode->i_lock);
166 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
167
168 mutex_init(&inode->i_mutex);
169 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
170
171 atomic_set(&inode->i_dio_count, 0);
172
173 mapping->a_ops = &empty_aops;
174 mapping->host = inode;
175 mapping->flags = 0;
176 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
177 mapping->assoc_mapping = NULL;
178 mapping->backing_dev_info = &default_backing_dev_info;
179 mapping->writeback_index = 0;
180
181 /*
182 * If the block_device provides a backing_dev_info for client
183 * inodes then use that. Otherwise the inode share the bdev's
184 * backing_dev_info.
185 */
186 if (sb->s_bdev) {
187 struct backing_dev_info *bdi;
188
189 bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
190 mapping->backing_dev_info = bdi;
191 }
192 inode->i_private = NULL;
193 inode->i_mapping = mapping;
194#ifdef CONFIG_FS_POSIX_ACL
195 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
196#endif
197
198#ifdef CONFIG_FSNOTIFY
199 inode->i_fsnotify_mask = 0;
200#endif
201
202 this_cpu_inc(nr_inodes);
203
204 return 0;
205out:
206 return -ENOMEM;
207}
208EXPORT_SYMBOL(inode_init_always);
209
210static struct inode *alloc_inode(struct super_block *sb)
211{
212 struct inode *inode;
213
214 if (sb->s_op->alloc_inode)
215 inode = sb->s_op->alloc_inode(sb);
216 else
217 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
218
219 if (!inode)
220 return NULL;
221
222 if (unlikely(inode_init_always(sb, inode))) {
223 if (inode->i_sb->s_op->destroy_inode)
224 inode->i_sb->s_op->destroy_inode(inode);
225 else
226 kmem_cache_free(inode_cachep, inode);
227 return NULL;
228 }
229
230 return inode;
231}
232
233void free_inode_nonrcu(struct inode *inode)
234{
235 kmem_cache_free(inode_cachep, inode);
236}
237EXPORT_SYMBOL(free_inode_nonrcu);
238
239void __destroy_inode(struct inode *inode)
240{
241 BUG_ON(inode_has_buffers(inode));
242 security_inode_free(inode);
243 fsnotify_inode_delete(inode);
244#ifdef CONFIG_FS_POSIX_ACL
245 if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
246 posix_acl_release(inode->i_acl);
247 if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
248 posix_acl_release(inode->i_default_acl);
249#endif
250 this_cpu_dec(nr_inodes);
251}
252EXPORT_SYMBOL(__destroy_inode);
253
254static void i_callback(struct rcu_head *head)
255{
256 struct inode *inode = container_of(head, struct inode, i_rcu);
257 INIT_LIST_HEAD(&inode->i_dentry);
258 kmem_cache_free(inode_cachep, inode);
259}
260
261static void destroy_inode(struct inode *inode)
262{
263 BUG_ON(!list_empty(&inode->i_lru));
264 __destroy_inode(inode);
265 if (inode->i_sb->s_op->destroy_inode)
266 inode->i_sb->s_op->destroy_inode(inode);
267 else
268 call_rcu(&inode->i_rcu, i_callback);
269}
270
271void address_space_init_once(struct address_space *mapping)
272{
273 memset(mapping, 0, sizeof(*mapping));
274 INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
275 spin_lock_init(&mapping->tree_lock);
276 mutex_init(&mapping->i_mmap_mutex);
277 INIT_LIST_HEAD(&mapping->private_list);
278 spin_lock_init(&mapping->private_lock);
279 INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
280 INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
281}
282EXPORT_SYMBOL(address_space_init_once);
283
284/*
285 * These are initializations that only need to be done
286 * once, because the fields are idempotent across use
287 * of the inode, so let the slab aware of that.
288 */
289void inode_init_once(struct inode *inode)
290{
291 memset(inode, 0, sizeof(*inode));
292 INIT_HLIST_NODE(&inode->i_hash);
293 INIT_LIST_HEAD(&inode->i_dentry);
294 INIT_LIST_HEAD(&inode->i_devices);
295 INIT_LIST_HEAD(&inode->i_wb_list);
296 INIT_LIST_HEAD(&inode->i_lru);
297 address_space_init_once(&inode->i_data);
298 i_size_ordered_init(inode);
299#ifdef CONFIG_FSNOTIFY
300 INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
301#endif
302}
303EXPORT_SYMBOL(inode_init_once);
304
305static void init_once(void *foo)
306{
307 struct inode *inode = (struct inode *) foo;
308
309 inode_init_once(inode);
310}
311
312/*
313 * inode->i_lock must be held
314 */
315void __iget(struct inode *inode)
316{
317 atomic_inc(&inode->i_count);
318}
319
320/*
321 * get additional reference to inode; caller must already hold one.
322 */
323void ihold(struct inode *inode)
324{
325 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
326}
327EXPORT_SYMBOL(ihold);
328
329static void inode_lru_list_add(struct inode *inode)
330{
331 spin_lock(&inode->i_sb->s_inode_lru_lock);
332 if (list_empty(&inode->i_lru)) {
333 list_add(&inode->i_lru, &inode->i_sb->s_inode_lru);
334 inode->i_sb->s_nr_inodes_unused++;
335 this_cpu_inc(nr_unused);
336 }
337 spin_unlock(&inode->i_sb->s_inode_lru_lock);
338}
339
340static void inode_lru_list_del(struct inode *inode)
341{
342 spin_lock(&inode->i_sb->s_inode_lru_lock);
343 if (!list_empty(&inode->i_lru)) {
344 list_del_init(&inode->i_lru);
345 inode->i_sb->s_nr_inodes_unused--;
346 this_cpu_dec(nr_unused);
347 }
348 spin_unlock(&inode->i_sb->s_inode_lru_lock);
349}
350
351/**
352 * inode_sb_list_add - add inode to the superblock list of inodes
353 * @inode: inode to add
354 */
355void inode_sb_list_add(struct inode *inode)
356{
357 spin_lock(&inode_sb_list_lock);
358 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
359 spin_unlock(&inode_sb_list_lock);
360}
361EXPORT_SYMBOL_GPL(inode_sb_list_add);
362
363static inline void inode_sb_list_del(struct inode *inode)
364{
365 if (!list_empty(&inode->i_sb_list)) {
366 spin_lock(&inode_sb_list_lock);
367 list_del_init(&inode->i_sb_list);
368 spin_unlock(&inode_sb_list_lock);
369 }
370}
371
372static unsigned long hash(struct super_block *sb, unsigned long hashval)
373{
374 unsigned long tmp;
375
376 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
377 L1_CACHE_BYTES;
378 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
379 return tmp & i_hash_mask;
380}
381
382/**
383 * __insert_inode_hash - hash an inode
384 * @inode: unhashed inode
385 * @hashval: unsigned long value used to locate this object in the
386 * inode_hashtable.
387 *
388 * Add an inode to the inode hash for this superblock.
389 */
390void __insert_inode_hash(struct inode *inode, unsigned long hashval)
391{
392 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
393
394 spin_lock(&inode_hash_lock);
395 spin_lock(&inode->i_lock);
396 hlist_add_head(&inode->i_hash, b);
397 spin_unlock(&inode->i_lock);
398 spin_unlock(&inode_hash_lock);
399}
400EXPORT_SYMBOL(__insert_inode_hash);
401
402/**
403 * __remove_inode_hash - remove an inode from the hash
404 * @inode: inode to unhash
405 *
406 * Remove an inode from the superblock.
407 */
408void __remove_inode_hash(struct inode *inode)
409{
410 spin_lock(&inode_hash_lock);
411 spin_lock(&inode->i_lock);
412 hlist_del_init(&inode->i_hash);
413 spin_unlock(&inode->i_lock);
414 spin_unlock(&inode_hash_lock);
415}
416EXPORT_SYMBOL(__remove_inode_hash);
417
418void end_writeback(struct inode *inode)
419{
420 might_sleep();
421 /*
422 * We have to cycle tree_lock here because reclaim can be still in the
423 * process of removing the last page (in __delete_from_page_cache())
424 * and we must not free mapping under it.
425 */
426 spin_lock_irq(&inode->i_data.tree_lock);
427 BUG_ON(inode->i_data.nrpages);
428 spin_unlock_irq(&inode->i_data.tree_lock);
429 BUG_ON(!list_empty(&inode->i_data.private_list));
430 BUG_ON(!(inode->i_state & I_FREEING));
431 BUG_ON(inode->i_state & I_CLEAR);
432 inode_sync_wait(inode);
433 /* don't need i_lock here, no concurrent mods to i_state */
434 inode->i_state = I_FREEING | I_CLEAR;
435}
436EXPORT_SYMBOL(end_writeback);
437
438/*
439 * Free the inode passed in, removing it from the lists it is still connected
440 * to. We remove any pages still attached to the inode and wait for any IO that
441 * is still in progress before finally destroying the inode.
442 *
443 * An inode must already be marked I_FREEING so that we avoid the inode being
444 * moved back onto lists if we race with other code that manipulates the lists
445 * (e.g. writeback_single_inode). The caller is responsible for setting this.
446 *
447 * An inode must already be removed from the LRU list before being evicted from
448 * the cache. This should occur atomically with setting the I_FREEING state
449 * flag, so no inodes here should ever be on the LRU when being evicted.
450 */
451static void evict(struct inode *inode)
452{
453 const struct super_operations *op = inode->i_sb->s_op;
454
455 BUG_ON(!(inode->i_state & I_FREEING));
456 BUG_ON(!list_empty(&inode->i_lru));
457
458 if (!list_empty(&inode->i_wb_list))
459 inode_wb_list_del(inode);
460
461 inode_sb_list_del(inode);
462
463 if (op->evict_inode) {
464 op->evict_inode(inode);
465 } else {
466 if (inode->i_data.nrpages)
467 truncate_inode_pages(&inode->i_data, 0);
468 end_writeback(inode);
469 }
470 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
471 bd_forget(inode);
472 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
473 cd_forget(inode);
474
475 remove_inode_hash(inode);
476
477 spin_lock(&inode->i_lock);
478 wake_up_bit(&inode->i_state, __I_NEW);
479 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
480 spin_unlock(&inode->i_lock);
481
482 destroy_inode(inode);
483}
484
485/*
486 * dispose_list - dispose of the contents of a local list
487 * @head: the head of the list to free
488 *
489 * Dispose-list gets a local list with local inodes in it, so it doesn't
490 * need to worry about list corruption and SMP locks.
491 */
492static void dispose_list(struct list_head *head)
493{
494 while (!list_empty(head)) {
495 struct inode *inode;
496
497 inode = list_first_entry(head, struct inode, i_lru);
498 list_del_init(&inode->i_lru);
499
500 evict(inode);
501 }
502}
503
504/**
505 * evict_inodes - evict all evictable inodes for a superblock
506 * @sb: superblock to operate on
507 *
508 * Make sure that no inodes with zero refcount are retained. This is
509 * called by superblock shutdown after having MS_ACTIVE flag removed,
510 * so any inode reaching zero refcount during or after that call will
511 * be immediately evicted.
512 */
513void evict_inodes(struct super_block *sb)
514{
515 struct inode *inode, *next;
516 LIST_HEAD(dispose);
517
518 spin_lock(&inode_sb_list_lock);
519 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
520 if (atomic_read(&inode->i_count))
521 continue;
522
523 spin_lock(&inode->i_lock);
524 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
525 spin_unlock(&inode->i_lock);
526 continue;
527 }
528
529 inode->i_state |= I_FREEING;
530 inode_lru_list_del(inode);
531 spin_unlock(&inode->i_lock);
532 list_add(&inode->i_lru, &dispose);
533 }
534 spin_unlock(&inode_sb_list_lock);
535
536 dispose_list(&dispose);
537}
538
539/**
540 * invalidate_inodes - attempt to free all inodes on a superblock
541 * @sb: superblock to operate on
542 * @kill_dirty: flag to guide handling of dirty inodes
543 *
544 * Attempts to free all inodes for a given superblock. If there were any
545 * busy inodes return a non-zero value, else zero.
546 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
547 * them as busy.
548 */
549int invalidate_inodes(struct super_block *sb, bool kill_dirty)
550{
551 int busy = 0;
552 struct inode *inode, *next;
553 LIST_HEAD(dispose);
554
555 spin_lock(&inode_sb_list_lock);
556 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
557 spin_lock(&inode->i_lock);
558 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
559 spin_unlock(&inode->i_lock);
560 continue;
561 }
562 if (inode->i_state & I_DIRTY && !kill_dirty) {
563 spin_unlock(&inode->i_lock);
564 busy = 1;
565 continue;
566 }
567 if (atomic_read(&inode->i_count)) {
568 spin_unlock(&inode->i_lock);
569 busy = 1;
570 continue;
571 }
572
573 inode->i_state |= I_FREEING;
574 inode_lru_list_del(inode);
575 spin_unlock(&inode->i_lock);
576 list_add(&inode->i_lru, &dispose);
577 }
578 spin_unlock(&inode_sb_list_lock);
579
580 dispose_list(&dispose);
581
582 return busy;
583}
584
585static int can_unuse(struct inode *inode)
586{
587 if (inode->i_state & ~I_REFERENCED)
588 return 0;
589 if (inode_has_buffers(inode))
590 return 0;
591 if (atomic_read(&inode->i_count))
592 return 0;
593 if (inode->i_data.nrpages)
594 return 0;
595 return 1;
596}
597
598/*
599 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
600 * This is called from the superblock shrinker function with a number of inodes
601 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
602 * then are freed outside inode_lock by dispose_list().
603 *
604 * Any inodes which are pinned purely because of attached pagecache have their
605 * pagecache removed. If the inode has metadata buffers attached to
606 * mapping->private_list then try to remove them.
607 *
608 * If the inode has the I_REFERENCED flag set, then it means that it has been
609 * used recently - the flag is set in iput_final(). When we encounter such an
610 * inode, clear the flag and move it to the back of the LRU so it gets another
611 * pass through the LRU before it gets reclaimed. This is necessary because of
612 * the fact we are doing lazy LRU updates to minimise lock contention so the
613 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
614 * with this flag set because they are the inodes that are out of order.
615 */
616void prune_icache_sb(struct super_block *sb, int nr_to_scan)
617{
618 LIST_HEAD(freeable);
619 int nr_scanned;
620 unsigned long reap = 0;
621
622 spin_lock(&sb->s_inode_lru_lock);
623 for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) {
624 struct inode *inode;
625
626 if (list_empty(&sb->s_inode_lru))
627 break;
628
629 inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru);
630
631 /*
632 * we are inverting the sb->s_inode_lru_lock/inode->i_lock here,
633 * so use a trylock. If we fail to get the lock, just move the
634 * inode to the back of the list so we don't spin on it.
635 */
636 if (!spin_trylock(&inode->i_lock)) {
637 list_move(&inode->i_lru, &sb->s_inode_lru);
638 continue;
639 }
640
641 /*
642 * Referenced or dirty inodes are still in use. Give them
643 * another pass through the LRU as we canot reclaim them now.
644 */
645 if (atomic_read(&inode->i_count) ||
646 (inode->i_state & ~I_REFERENCED)) {
647 list_del_init(&inode->i_lru);
648 spin_unlock(&inode->i_lock);
649 sb->s_nr_inodes_unused--;
650 this_cpu_dec(nr_unused);
651 continue;
652 }
653
654 /* recently referenced inodes get one more pass */
655 if (inode->i_state & I_REFERENCED) {
656 inode->i_state &= ~I_REFERENCED;
657 list_move(&inode->i_lru, &sb->s_inode_lru);
658 spin_unlock(&inode->i_lock);
659 continue;
660 }
661 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
662 __iget(inode);
663 spin_unlock(&inode->i_lock);
664 spin_unlock(&sb->s_inode_lru_lock);
665 if (remove_inode_buffers(inode))
666 reap += invalidate_mapping_pages(&inode->i_data,
667 0, -1);
668 iput(inode);
669 spin_lock(&sb->s_inode_lru_lock);
670
671 if (inode != list_entry(sb->s_inode_lru.next,
672 struct inode, i_lru))
673 continue; /* wrong inode or list_empty */
674 /* avoid lock inversions with trylock */
675 if (!spin_trylock(&inode->i_lock))
676 continue;
677 if (!can_unuse(inode)) {
678 spin_unlock(&inode->i_lock);
679 continue;
680 }
681 }
682 WARN_ON(inode->i_state & I_NEW);
683 inode->i_state |= I_FREEING;
684 spin_unlock(&inode->i_lock);
685
686 list_move(&inode->i_lru, &freeable);
687 sb->s_nr_inodes_unused--;
688 this_cpu_dec(nr_unused);
689 }
690 if (current_is_kswapd())
691 __count_vm_events(KSWAPD_INODESTEAL, reap);
692 else
693 __count_vm_events(PGINODESTEAL, reap);
694 spin_unlock(&sb->s_inode_lru_lock);
695
696 dispose_list(&freeable);
697}
698
699static void __wait_on_freeing_inode(struct inode *inode);
700/*
701 * Called with the inode lock held.
702 */
703static struct inode *find_inode(struct super_block *sb,
704 struct hlist_head *head,
705 int (*test)(struct inode *, void *),
706 void *data)
707{
708 struct hlist_node *node;
709 struct inode *inode = NULL;
710
711repeat:
712 hlist_for_each_entry(inode, node, head, i_hash) {
713 spin_lock(&inode->i_lock);
714 if (inode->i_sb != sb) {
715 spin_unlock(&inode->i_lock);
716 continue;
717 }
718 if (!test(inode, data)) {
719 spin_unlock(&inode->i_lock);
720 continue;
721 }
722 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
723 __wait_on_freeing_inode(inode);
724 goto repeat;
725 }
726 __iget(inode);
727 spin_unlock(&inode->i_lock);
728 return inode;
729 }
730 return NULL;
731}
732
733/*
734 * find_inode_fast is the fast path version of find_inode, see the comment at
735 * iget_locked for details.
736 */
737static struct inode *find_inode_fast(struct super_block *sb,
738 struct hlist_head *head, unsigned long ino)
739{
740 struct hlist_node *node;
741 struct inode *inode = NULL;
742
743repeat:
744 hlist_for_each_entry(inode, node, head, i_hash) {
745 spin_lock(&inode->i_lock);
746 if (inode->i_ino != ino) {
747 spin_unlock(&inode->i_lock);
748 continue;
749 }
750 if (inode->i_sb != sb) {
751 spin_unlock(&inode->i_lock);
752 continue;
753 }
754 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
755 __wait_on_freeing_inode(inode);
756 goto repeat;
757 }
758 __iget(inode);
759 spin_unlock(&inode->i_lock);
760 return inode;
761 }
762 return NULL;
763}
764
765/*
766 * Each cpu owns a range of LAST_INO_BATCH numbers.
767 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
768 * to renew the exhausted range.
769 *
770 * This does not significantly increase overflow rate because every CPU can
771 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
772 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
773 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
774 * overflow rate by 2x, which does not seem too significant.
775 *
776 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
777 * error if st_ino won't fit in target struct field. Use 32bit counter
778 * here to attempt to avoid that.
779 */
780#define LAST_INO_BATCH 1024
781static DEFINE_PER_CPU(unsigned int, last_ino);
782
783unsigned int get_next_ino(void)
784{
785 unsigned int *p = &get_cpu_var(last_ino);
786 unsigned int res = *p;
787
788#ifdef CONFIG_SMP
789 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
790 static atomic_t shared_last_ino;
791 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
792
793 res = next - LAST_INO_BATCH;
794 }
795#endif
796
797 *p = ++res;
798 put_cpu_var(last_ino);
799 return res;
800}
801EXPORT_SYMBOL(get_next_ino);
802
803/**
804 * new_inode_pseudo - obtain an inode
805 * @sb: superblock
806 *
807 * Allocates a new inode for given superblock.
808 * Inode wont be chained in superblock s_inodes list
809 * This means :
810 * - fs can't be unmount
811 * - quotas, fsnotify, writeback can't work
812 */
813struct inode *new_inode_pseudo(struct super_block *sb)
814{
815 struct inode *inode = alloc_inode(sb);
816
817 if (inode) {
818 spin_lock(&inode->i_lock);
819 inode->i_state = 0;
820 spin_unlock(&inode->i_lock);
821 INIT_LIST_HEAD(&inode->i_sb_list);
822 }
823 return inode;
824}
825
826/**
827 * new_inode - obtain an inode
828 * @sb: superblock
829 *
830 * Allocates a new inode for given superblock. The default gfp_mask
831 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
832 * If HIGHMEM pages are unsuitable or it is known that pages allocated
833 * for the page cache are not reclaimable or migratable,
834 * mapping_set_gfp_mask() must be called with suitable flags on the
835 * newly created inode's mapping
836 *
837 */
838struct inode *new_inode(struct super_block *sb)
839{
840 struct inode *inode;
841
842 spin_lock_prefetch(&inode_sb_list_lock);
843
844 inode = new_inode_pseudo(sb);
845 if (inode)
846 inode_sb_list_add(inode);
847 return inode;
848}
849EXPORT_SYMBOL(new_inode);
850
851#ifdef CONFIG_DEBUG_LOCK_ALLOC
852void lockdep_annotate_inode_mutex_key(struct inode *inode)
853{
854 if (S_ISDIR(inode->i_mode)) {
855 struct file_system_type *type = inode->i_sb->s_type;
856
857 /* Set new key only if filesystem hasn't already changed it */
858 if (!lockdep_match_class(&inode->i_mutex,
859 &type->i_mutex_key)) {
860 /*
861 * ensure nobody is actually holding i_mutex
862 */
863 mutex_destroy(&inode->i_mutex);
864 mutex_init(&inode->i_mutex);
865 lockdep_set_class(&inode->i_mutex,
866 &type->i_mutex_dir_key);
867 }
868 }
869}
870EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
871#endif
872
873/**
874 * unlock_new_inode - clear the I_NEW state and wake up any waiters
875 * @inode: new inode to unlock
876 *
877 * Called when the inode is fully initialised to clear the new state of the
878 * inode and wake up anyone waiting for the inode to finish initialisation.
879 */
880void unlock_new_inode(struct inode *inode)
881{
882 lockdep_annotate_inode_mutex_key(inode);
883 spin_lock(&inode->i_lock);
884 WARN_ON(!(inode->i_state & I_NEW));
885 inode->i_state &= ~I_NEW;
886 wake_up_bit(&inode->i_state, __I_NEW);
887 spin_unlock(&inode->i_lock);
888}
889EXPORT_SYMBOL(unlock_new_inode);
890
891/**
892 * iget5_locked - obtain an inode from a mounted file system
893 * @sb: super block of file system
894 * @hashval: hash value (usually inode number) to get
895 * @test: callback used for comparisons between inodes
896 * @set: callback used to initialize a new struct inode
897 * @data: opaque data pointer to pass to @test and @set
898 *
899 * Search for the inode specified by @hashval and @data in the inode cache,
900 * and if present it is return it with an increased reference count. This is
901 * a generalized version of iget_locked() for file systems where the inode
902 * number is not sufficient for unique identification of an inode.
903 *
904 * If the inode is not in cache, allocate a new inode and return it locked,
905 * hashed, and with the I_NEW flag set. The file system gets to fill it in
906 * before unlocking it via unlock_new_inode().
907 *
908 * Note both @test and @set are called with the inode_hash_lock held, so can't
909 * sleep.
910 */
911struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
912 int (*test)(struct inode *, void *),
913 int (*set)(struct inode *, void *), void *data)
914{
915 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
916 struct inode *inode;
917
918 spin_lock(&inode_hash_lock);
919 inode = find_inode(sb, head, test, data);
920 spin_unlock(&inode_hash_lock);
921
922 if (inode) {
923 wait_on_inode(inode);
924 return inode;
925 }
926
927 inode = alloc_inode(sb);
928 if (inode) {
929 struct inode *old;
930
931 spin_lock(&inode_hash_lock);
932 /* We released the lock, so.. */
933 old = find_inode(sb, head, test, data);
934 if (!old) {
935 if (set(inode, data))
936 goto set_failed;
937
938 spin_lock(&inode->i_lock);
939 inode->i_state = I_NEW;
940 hlist_add_head(&inode->i_hash, head);
941 spin_unlock(&inode->i_lock);
942 inode_sb_list_add(inode);
943 spin_unlock(&inode_hash_lock);
944
945 /* Return the locked inode with I_NEW set, the
946 * caller is responsible for filling in the contents
947 */
948 return inode;
949 }
950
951 /*
952 * Uhhuh, somebody else created the same inode under
953 * us. Use the old inode instead of the one we just
954 * allocated.
955 */
956 spin_unlock(&inode_hash_lock);
957 destroy_inode(inode);
958 inode = old;
959 wait_on_inode(inode);
960 }
961 return inode;
962
963set_failed:
964 spin_unlock(&inode_hash_lock);
965 destroy_inode(inode);
966 return NULL;
967}
968EXPORT_SYMBOL(iget5_locked);
969
970/**
971 * iget_locked - obtain an inode from a mounted file system
972 * @sb: super block of file system
973 * @ino: inode number to get
974 *
975 * Search for the inode specified by @ino in the inode cache and if present
976 * return it with an increased reference count. This is for file systems
977 * where the inode number is sufficient for unique identification of an inode.
978 *
979 * If the inode is not in cache, allocate a new inode and return it locked,
980 * hashed, and with the I_NEW flag set. The file system gets to fill it in
981 * before unlocking it via unlock_new_inode().
982 */
983struct inode *iget_locked(struct super_block *sb, unsigned long ino)
984{
985 struct hlist_head *head = inode_hashtable + hash(sb, ino);
986 struct inode *inode;
987
988 spin_lock(&inode_hash_lock);
989 inode = find_inode_fast(sb, head, ino);
990 spin_unlock(&inode_hash_lock);
991 if (inode) {
992 wait_on_inode(inode);
993 return inode;
994 }
995
996 inode = alloc_inode(sb);
997 if (inode) {
998 struct inode *old;
999
1000 spin_lock(&inode_hash_lock);
1001 /* We released the lock, so.. */
1002 old = find_inode_fast(sb, head, ino);
1003 if (!old) {
1004 inode->i_ino = ino;
1005 spin_lock(&inode->i_lock);
1006 inode->i_state = I_NEW;
1007 hlist_add_head(&inode->i_hash, head);
1008 spin_unlock(&inode->i_lock);
1009 inode_sb_list_add(inode);
1010 spin_unlock(&inode_hash_lock);
1011
1012 /* Return the locked inode with I_NEW set, the
1013 * caller is responsible for filling in the contents
1014 */
1015 return inode;
1016 }
1017
1018 /*
1019 * Uhhuh, somebody else created the same inode under
1020 * us. Use the old inode instead of the one we just
1021 * allocated.
1022 */
1023 spin_unlock(&inode_hash_lock);
1024 destroy_inode(inode);
1025 inode = old;
1026 wait_on_inode(inode);
1027 }
1028 return inode;
1029}
1030EXPORT_SYMBOL(iget_locked);
1031
1032/*
1033 * search the inode cache for a matching inode number.
1034 * If we find one, then the inode number we are trying to
1035 * allocate is not unique and so we should not use it.
1036 *
1037 * Returns 1 if the inode number is unique, 0 if it is not.
1038 */
1039static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1040{
1041 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1042 struct hlist_node *node;
1043 struct inode *inode;
1044
1045 spin_lock(&inode_hash_lock);
1046 hlist_for_each_entry(inode, node, b, i_hash) {
1047 if (inode->i_ino == ino && inode->i_sb == sb) {
1048 spin_unlock(&inode_hash_lock);
1049 return 0;
1050 }
1051 }
1052 spin_unlock(&inode_hash_lock);
1053
1054 return 1;
1055}
1056
1057/**
1058 * iunique - get a unique inode number
1059 * @sb: superblock
1060 * @max_reserved: highest reserved inode number
1061 *
1062 * Obtain an inode number that is unique on the system for a given
1063 * superblock. This is used by file systems that have no natural
1064 * permanent inode numbering system. An inode number is returned that
1065 * is higher than the reserved limit but unique.
1066 *
1067 * BUGS:
1068 * With a large number of inodes live on the file system this function
1069 * currently becomes quite slow.
1070 */
1071ino_t iunique(struct super_block *sb, ino_t max_reserved)
1072{
1073 /*
1074 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1075 * error if st_ino won't fit in target struct field. Use 32bit counter
1076 * here to attempt to avoid that.
1077 */
1078 static DEFINE_SPINLOCK(iunique_lock);
1079 static unsigned int counter;
1080 ino_t res;
1081
1082 spin_lock(&iunique_lock);
1083 do {
1084 if (counter <= max_reserved)
1085 counter = max_reserved + 1;
1086 res = counter++;
1087 } while (!test_inode_iunique(sb, res));
1088 spin_unlock(&iunique_lock);
1089
1090 return res;
1091}
1092EXPORT_SYMBOL(iunique);
1093
1094struct inode *igrab(struct inode *inode)
1095{
1096 spin_lock(&inode->i_lock);
1097 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1098 __iget(inode);
1099 spin_unlock(&inode->i_lock);
1100 } else {
1101 spin_unlock(&inode->i_lock);
1102 /*
1103 * Handle the case where s_op->clear_inode is not been
1104 * called yet, and somebody is calling igrab
1105 * while the inode is getting freed.
1106 */
1107 inode = NULL;
1108 }
1109 return inode;
1110}
1111EXPORT_SYMBOL(igrab);
1112
1113/**
1114 * ilookup5_nowait - search for an inode in the inode cache
1115 * @sb: super block of file system to search
1116 * @hashval: hash value (usually inode number) to search for
1117 * @test: callback used for comparisons between inodes
1118 * @data: opaque data pointer to pass to @test
1119 *
1120 * Search for the inode specified by @hashval and @data in the inode cache.
1121 * If the inode is in the cache, the inode is returned with an incremented
1122 * reference count.
1123 *
1124 * Note: I_NEW is not waited upon so you have to be very careful what you do
1125 * with the returned inode. You probably should be using ilookup5() instead.
1126 *
1127 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1128 */
1129struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1130 int (*test)(struct inode *, void *), void *data)
1131{
1132 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1133 struct inode *inode;
1134
1135 spin_lock(&inode_hash_lock);
1136 inode = find_inode(sb, head, test, data);
1137 spin_unlock(&inode_hash_lock);
1138
1139 return inode;
1140}
1141EXPORT_SYMBOL(ilookup5_nowait);
1142
1143/**
1144 * ilookup5 - search for an inode in the inode cache
1145 * @sb: super block of file system to search
1146 * @hashval: hash value (usually inode number) to search for
1147 * @test: callback used for comparisons between inodes
1148 * @data: opaque data pointer to pass to @test
1149 *
1150 * Search for the inode specified by @hashval and @data in the inode cache,
1151 * and if the inode is in the cache, return the inode with an incremented
1152 * reference count. Waits on I_NEW before returning the inode.
1153 * returned with an incremented reference count.
1154 *
1155 * This is a generalized version of ilookup() for file systems where the
1156 * inode number is not sufficient for unique identification of an inode.
1157 *
1158 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1159 */
1160struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1161 int (*test)(struct inode *, void *), void *data)
1162{
1163 struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
1164
1165 if (inode)
1166 wait_on_inode(inode);
1167 return inode;
1168}
1169EXPORT_SYMBOL(ilookup5);
1170
1171/**
1172 * ilookup - search for an inode in the inode cache
1173 * @sb: super block of file system to search
1174 * @ino: inode number to search for
1175 *
1176 * Search for the inode @ino in the inode cache, and if the inode is in the
1177 * cache, the inode is returned with an incremented reference count.
1178 */
1179struct inode *ilookup(struct super_block *sb, unsigned long ino)
1180{
1181 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1182 struct inode *inode;
1183
1184 spin_lock(&inode_hash_lock);
1185 inode = find_inode_fast(sb, head, ino);
1186 spin_unlock(&inode_hash_lock);
1187
1188 if (inode)
1189 wait_on_inode(inode);
1190 return inode;
1191}
1192EXPORT_SYMBOL(ilookup);
1193
1194int insert_inode_locked(struct inode *inode)
1195{
1196 struct super_block *sb = inode->i_sb;
1197 ino_t ino = inode->i_ino;
1198 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1199
1200 while (1) {
1201 struct hlist_node *node;
1202 struct inode *old = NULL;
1203 spin_lock(&inode_hash_lock);
1204 hlist_for_each_entry(old, node, head, i_hash) {
1205 if (old->i_ino != ino)
1206 continue;
1207 if (old->i_sb != sb)
1208 continue;
1209 spin_lock(&old->i_lock);
1210 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1211 spin_unlock(&old->i_lock);
1212 continue;
1213 }
1214 break;
1215 }
1216 if (likely(!node)) {
1217 spin_lock(&inode->i_lock);
1218 inode->i_state |= I_NEW;
1219 hlist_add_head(&inode->i_hash, head);
1220 spin_unlock(&inode->i_lock);
1221 spin_unlock(&inode_hash_lock);
1222 return 0;
1223 }
1224 __iget(old);
1225 spin_unlock(&old->i_lock);
1226 spin_unlock(&inode_hash_lock);
1227 wait_on_inode(old);
1228 if (unlikely(!inode_unhashed(old))) {
1229 iput(old);
1230 return -EBUSY;
1231 }
1232 iput(old);
1233 }
1234}
1235EXPORT_SYMBOL(insert_inode_locked);
1236
1237int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1238 int (*test)(struct inode *, void *), void *data)
1239{
1240 struct super_block *sb = inode->i_sb;
1241 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1242
1243 while (1) {
1244 struct hlist_node *node;
1245 struct inode *old = NULL;
1246
1247 spin_lock(&inode_hash_lock);
1248 hlist_for_each_entry(old, node, head, i_hash) {
1249 if (old->i_sb != sb)
1250 continue;
1251 if (!test(old, data))
1252 continue;
1253 spin_lock(&old->i_lock);
1254 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1255 spin_unlock(&old->i_lock);
1256 continue;
1257 }
1258 break;
1259 }
1260 if (likely(!node)) {
1261 spin_lock(&inode->i_lock);
1262 inode->i_state |= I_NEW;
1263 hlist_add_head(&inode->i_hash, head);
1264 spin_unlock(&inode->i_lock);
1265 spin_unlock(&inode_hash_lock);
1266 return 0;
1267 }
1268 __iget(old);
1269 spin_unlock(&old->i_lock);
1270 spin_unlock(&inode_hash_lock);
1271 wait_on_inode(old);
1272 if (unlikely(!inode_unhashed(old))) {
1273 iput(old);
1274 return -EBUSY;
1275 }
1276 iput(old);
1277 }
1278}
1279EXPORT_SYMBOL(insert_inode_locked4);
1280
1281
1282int generic_delete_inode(struct inode *inode)
1283{
1284 return 1;
1285}
1286EXPORT_SYMBOL(generic_delete_inode);
1287
1288/*
1289 * Normal UNIX filesystem behaviour: delete the
1290 * inode when the usage count drops to zero, and
1291 * i_nlink is zero.
1292 */
1293int generic_drop_inode(struct inode *inode)
1294{
1295 return !inode->i_nlink || inode_unhashed(inode);
1296}
1297EXPORT_SYMBOL_GPL(generic_drop_inode);
1298
1299/*
1300 * Called when we're dropping the last reference
1301 * to an inode.
1302 *
1303 * Call the FS "drop_inode()" function, defaulting to
1304 * the legacy UNIX filesystem behaviour. If it tells
1305 * us to evict inode, do so. Otherwise, retain inode
1306 * in cache if fs is alive, sync and evict if fs is
1307 * shutting down.
1308 */
1309static void iput_final(struct inode *inode)
1310{
1311 struct super_block *sb = inode->i_sb;
1312 const struct super_operations *op = inode->i_sb->s_op;
1313 int drop;
1314
1315 WARN_ON(inode->i_state & I_NEW);
1316
1317 if (op->drop_inode)
1318 drop = op->drop_inode(inode);
1319 else
1320 drop = generic_drop_inode(inode);
1321
1322 if (!drop && (sb->s_flags & MS_ACTIVE)) {
1323 inode->i_state |= I_REFERENCED;
1324 if (!(inode->i_state & (I_DIRTY|I_SYNC)))
1325 inode_lru_list_add(inode);
1326 spin_unlock(&inode->i_lock);
1327 return;
1328 }
1329
1330 if (!drop) {
1331 inode->i_state |= I_WILL_FREE;
1332 spin_unlock(&inode->i_lock);
1333 write_inode_now(inode, 1);
1334 spin_lock(&inode->i_lock);
1335 WARN_ON(inode->i_state & I_NEW);
1336 inode->i_state &= ~I_WILL_FREE;
1337 }
1338
1339 inode->i_state |= I_FREEING;
1340 if (!list_empty(&inode->i_lru))
1341 inode_lru_list_del(inode);
1342 spin_unlock(&inode->i_lock);
1343
1344 evict(inode);
1345}
1346
1347/**
1348 * iput - put an inode
1349 * @inode: inode to put
1350 *
1351 * Puts an inode, dropping its usage count. If the inode use count hits
1352 * zero, the inode is then freed and may also be destroyed.
1353 *
1354 * Consequently, iput() can sleep.
1355 */
1356void iput(struct inode *inode)
1357{
1358 if (inode) {
1359 BUG_ON(inode->i_state & I_CLEAR);
1360
1361 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock))
1362 iput_final(inode);
1363 }
1364}
1365EXPORT_SYMBOL(iput);
1366
1367/**
1368 * bmap - find a block number in a file
1369 * @inode: inode of file
1370 * @block: block to find
1371 *
1372 * Returns the block number on the device holding the inode that
1373 * is the disk block number for the block of the file requested.
1374 * That is, asked for block 4 of inode 1 the function will return the
1375 * disk block relative to the disk start that holds that block of the
1376 * file.
1377 */
1378sector_t bmap(struct inode *inode, sector_t block)
1379{
1380 sector_t res = 0;
1381 if (inode->i_mapping->a_ops->bmap)
1382 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1383 return res;
1384}
1385EXPORT_SYMBOL(bmap);
1386
1387/*
1388 * With relative atime, only update atime if the previous atime is
1389 * earlier than either the ctime or mtime or if at least a day has
1390 * passed since the last atime update.
1391 */
1392static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1393 struct timespec now)
1394{
1395
1396 if (!(mnt->mnt_flags & MNT_RELATIME))
1397 return 1;
1398 /*
1399 * Is mtime younger than atime? If yes, update atime:
1400 */
1401 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1402 return 1;
1403 /*
1404 * Is ctime younger than atime? If yes, update atime:
1405 */
1406 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1407 return 1;
1408
1409 /*
1410 * Is the previous atime value older than a day? If yes,
1411 * update atime:
1412 */
1413 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1414 return 1;
1415 /*
1416 * Good, we can skip the atime update:
1417 */
1418 return 0;
1419}
1420
1421/**
1422 * touch_atime - update the access time
1423 * @mnt: mount the inode is accessed on
1424 * @dentry: dentry accessed
1425 *
1426 * Update the accessed time on an inode and mark it for writeback.
1427 * This function automatically handles read only file systems and media,
1428 * as well as the "noatime" flag and inode specific "noatime" markers.
1429 */
1430void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
1431{
1432 struct inode *inode = dentry->d_inode;
1433 struct timespec now;
1434
1435 if (inode->i_flags & S_NOATIME)
1436 return;
1437 if (IS_NOATIME(inode))
1438 return;
1439 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1440 return;
1441
1442 if (mnt->mnt_flags & MNT_NOATIME)
1443 return;
1444 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1445 return;
1446
1447 now = current_fs_time(inode->i_sb);
1448
1449 if (!relatime_need_update(mnt, inode, now))
1450 return;
1451
1452 if (timespec_equal(&inode->i_atime, &now))
1453 return;
1454
1455 if (mnt_want_write(mnt))
1456 return;
1457
1458 inode->i_atime = now;
1459 mark_inode_dirty_sync(inode);
1460 mnt_drop_write(mnt);
1461}
1462EXPORT_SYMBOL(touch_atime);
1463
1464/**
1465 * file_update_time - update mtime and ctime time
1466 * @file: file accessed
1467 *
1468 * Update the mtime and ctime members of an inode and mark the inode
1469 * for writeback. Note that this function is meant exclusively for
1470 * usage in the file write path of filesystems, and filesystems may
1471 * choose to explicitly ignore update via this function with the
1472 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1473 * timestamps are handled by the server.
1474 */
1475
1476void file_update_time(struct file *file)
1477{
1478 struct inode *inode = file->f_path.dentry->d_inode;
1479 struct timespec now;
1480 enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
1481
1482 /* First try to exhaust all avenues to not sync */
1483 if (IS_NOCMTIME(inode))
1484 return;
1485
1486 now = current_fs_time(inode->i_sb);
1487 if (!timespec_equal(&inode->i_mtime, &now))
1488 sync_it = S_MTIME;
1489
1490 if (!timespec_equal(&inode->i_ctime, &now))
1491 sync_it |= S_CTIME;
1492
1493 if (IS_I_VERSION(inode))
1494 sync_it |= S_VERSION;
1495
1496 if (!sync_it)
1497 return;
1498
1499 /* Finally allowed to write? Takes lock. */
1500 if (mnt_want_write_file(file))
1501 return;
1502
1503 /* Only change inode inside the lock region */
1504 if (sync_it & S_VERSION)
1505 inode_inc_iversion(inode);
1506 if (sync_it & S_CTIME)
1507 inode->i_ctime = now;
1508 if (sync_it & S_MTIME)
1509 inode->i_mtime = now;
1510 mark_inode_dirty_sync(inode);
1511 mnt_drop_write(file->f_path.mnt);
1512}
1513EXPORT_SYMBOL(file_update_time);
1514
1515int inode_needs_sync(struct inode *inode)
1516{
1517 if (IS_SYNC(inode))
1518 return 1;
1519 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1520 return 1;
1521 return 0;
1522}
1523EXPORT_SYMBOL(inode_needs_sync);
1524
1525int inode_wait(void *word)
1526{
1527 schedule();
1528 return 0;
1529}
1530EXPORT_SYMBOL(inode_wait);
1531
1532/*
1533 * If we try to find an inode in the inode hash while it is being
1534 * deleted, we have to wait until the filesystem completes its
1535 * deletion before reporting that it isn't found. This function waits
1536 * until the deletion _might_ have completed. Callers are responsible
1537 * to recheck inode state.
1538 *
1539 * It doesn't matter if I_NEW is not set initially, a call to
1540 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1541 * will DTRT.
1542 */
1543static void __wait_on_freeing_inode(struct inode *inode)
1544{
1545 wait_queue_head_t *wq;
1546 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1547 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1548 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1549 spin_unlock(&inode->i_lock);
1550 spin_unlock(&inode_hash_lock);
1551 schedule();
1552 finish_wait(wq, &wait.wait);
1553 spin_lock(&inode_hash_lock);
1554}
1555
1556static __initdata unsigned long ihash_entries;
1557static int __init set_ihash_entries(char *str)
1558{
1559 if (!str)
1560 return 0;
1561 ihash_entries = simple_strtoul(str, &str, 0);
1562 return 1;
1563}
1564__setup("ihash_entries=", set_ihash_entries);
1565
1566/*
1567 * Initialize the waitqueues and inode hash table.
1568 */
1569void __init inode_init_early(void)
1570{
1571 int loop;
1572
1573 /* If hashes are distributed across NUMA nodes, defer
1574 * hash allocation until vmalloc space is available.
1575 */
1576 if (hashdist)
1577 return;
1578
1579 inode_hashtable =
1580 alloc_large_system_hash("Inode-cache",
1581 sizeof(struct hlist_head),
1582 ihash_entries,
1583 14,
1584 HASH_EARLY,
1585 &i_hash_shift,
1586 &i_hash_mask,
1587 0);
1588
1589 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1590 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1591}
1592
1593void __init inode_init(void)
1594{
1595 int loop;
1596
1597 /* inode slab cache */
1598 inode_cachep = kmem_cache_create("inode_cache",
1599 sizeof(struct inode),
1600 0,
1601 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1602 SLAB_MEM_SPREAD),
1603 init_once);
1604
1605 /* Hash may have been set up in inode_init_early */
1606 if (!hashdist)
1607 return;
1608
1609 inode_hashtable =
1610 alloc_large_system_hash("Inode-cache",
1611 sizeof(struct hlist_head),
1612 ihash_entries,
1613 14,
1614 0,
1615 &i_hash_shift,
1616 &i_hash_mask,
1617 0);
1618
1619 for (loop = 0; loop < (1 << i_hash_shift); loop++)
1620 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1621}
1622
1623void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1624{
1625 inode->i_mode = mode;
1626 if (S_ISCHR(mode)) {
1627 inode->i_fop = &def_chr_fops;
1628 inode->i_rdev = rdev;
1629 } else if (S_ISBLK(mode)) {
1630 inode->i_fop = &def_blk_fops;
1631 inode->i_rdev = rdev;
1632 } else if (S_ISFIFO(mode))
1633 inode->i_fop = &def_fifo_fops;
1634 else if (S_ISSOCK(mode))
1635 inode->i_fop = &bad_sock_fops;
1636 else
1637 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
1638 " inode %s:%lu\n", mode, inode->i_sb->s_id,
1639 inode->i_ino);
1640}
1641EXPORT_SYMBOL(init_special_inode);
1642
1643/**
1644 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1645 * @inode: New inode
1646 * @dir: Directory inode
1647 * @mode: mode of the new inode
1648 */
1649void inode_init_owner(struct inode *inode, const struct inode *dir,
1650 mode_t mode)
1651{
1652 inode->i_uid = current_fsuid();
1653 if (dir && dir->i_mode & S_ISGID) {
1654 inode->i_gid = dir->i_gid;
1655 if (S_ISDIR(mode))
1656 mode |= S_ISGID;
1657 } else
1658 inode->i_gid = current_fsgid();
1659 inode->i_mode = mode;
1660}
1661EXPORT_SYMBOL(inode_init_owner);
1662
1663/**
1664 * inode_owner_or_capable - check current task permissions to inode
1665 * @inode: inode being checked
1666 *
1667 * Return true if current either has CAP_FOWNER to the inode, or
1668 * owns the file.
1669 */
1670bool inode_owner_or_capable(const struct inode *inode)
1671{
1672 struct user_namespace *ns = inode_userns(inode);
1673
1674 if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
1675 return true;
1676 if (ns_capable(ns, CAP_FOWNER))
1677 return true;
1678 return false;
1679}
1680EXPORT_SYMBOL(inode_owner_or_capable);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * (C) 1997 Linus Torvalds
4 * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation)
5 */
6#include <linux/export.h>
7#include <linux/fs.h>
8#include <linux/mm.h>
9#include <linux/backing-dev.h>
10#include <linux/hash.h>
11#include <linux/swap.h>
12#include <linux/security.h>
13#include <linux/cdev.h>
14#include <linux/memblock.h>
15#include <linux/fsnotify.h>
16#include <linux/mount.h>
17#include <linux/posix_acl.h>
18#include <linux/prefetch.h>
19#include <linux/buffer_head.h> /* for inode_has_buffers */
20#include <linux/ratelimit.h>
21#include <linux/list_lru.h>
22#include <linux/iversion.h>
23#include <trace/events/writeback.h>
24#include "internal.h"
25
26/*
27 * Inode locking rules:
28 *
29 * inode->i_lock protects:
30 * inode->i_state, inode->i_hash, __iget()
31 * Inode LRU list locks protect:
32 * inode->i_sb->s_inode_lru, inode->i_lru
33 * inode->i_sb->s_inode_list_lock protects:
34 * inode->i_sb->s_inodes, inode->i_sb_list
35 * bdi->wb.list_lock protects:
36 * bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list
37 * inode_hash_lock protects:
38 * inode_hashtable, inode->i_hash
39 *
40 * Lock ordering:
41 *
42 * inode->i_sb->s_inode_list_lock
43 * inode->i_lock
44 * Inode LRU list locks
45 *
46 * bdi->wb.list_lock
47 * inode->i_lock
48 *
49 * inode_hash_lock
50 * inode->i_sb->s_inode_list_lock
51 * inode->i_lock
52 *
53 * iunique_lock
54 * inode_hash_lock
55 */
56
57static unsigned int i_hash_mask __read_mostly;
58static unsigned int i_hash_shift __read_mostly;
59static struct hlist_head *inode_hashtable __read_mostly;
60static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
61
62/*
63 * Empty aops. Can be used for the cases where the user does not
64 * define any of the address_space operations.
65 */
66const struct address_space_operations empty_aops = {
67};
68EXPORT_SYMBOL(empty_aops);
69
70/*
71 * Statistics gathering..
72 */
73struct inodes_stat_t inodes_stat;
74
75static DEFINE_PER_CPU(unsigned long, nr_inodes);
76static DEFINE_PER_CPU(unsigned long, nr_unused);
77
78static struct kmem_cache *inode_cachep __read_mostly;
79
80static long get_nr_inodes(void)
81{
82 int i;
83 long sum = 0;
84 for_each_possible_cpu(i)
85 sum += per_cpu(nr_inodes, i);
86 return sum < 0 ? 0 : sum;
87}
88
89static inline long get_nr_inodes_unused(void)
90{
91 int i;
92 long sum = 0;
93 for_each_possible_cpu(i)
94 sum += per_cpu(nr_unused, i);
95 return sum < 0 ? 0 : sum;
96}
97
98long get_nr_dirty_inodes(void)
99{
100 /* not actually dirty inodes, but a wild approximation */
101 long nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
102 return nr_dirty > 0 ? nr_dirty : 0;
103}
104
105/*
106 * Handle nr_inode sysctl
107 */
108#ifdef CONFIG_SYSCTL
109int proc_nr_inodes(struct ctl_table *table, int write,
110 void __user *buffer, size_t *lenp, loff_t *ppos)
111{
112 inodes_stat.nr_inodes = get_nr_inodes();
113 inodes_stat.nr_unused = get_nr_inodes_unused();
114 return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
115}
116#endif
117
118static int no_open(struct inode *inode, struct file *file)
119{
120 return -ENXIO;
121}
122
123/**
124 * inode_init_always - perform inode structure initialisation
125 * @sb: superblock inode belongs to
126 * @inode: inode to initialise
127 *
128 * These are initializations that need to be done on every inode
129 * allocation as the fields are not initialised by slab allocation.
130 */
131int inode_init_always(struct super_block *sb, struct inode *inode)
132{
133 static const struct inode_operations empty_iops;
134 static const struct file_operations no_open_fops = {.open = no_open};
135 struct address_space *const mapping = &inode->i_data;
136
137 inode->i_sb = sb;
138 inode->i_blkbits = sb->s_blocksize_bits;
139 inode->i_flags = 0;
140 atomic_set(&inode->i_count, 1);
141 inode->i_op = &empty_iops;
142 inode->i_fop = &no_open_fops;
143 inode->__i_nlink = 1;
144 inode->i_opflags = 0;
145 if (sb->s_xattr)
146 inode->i_opflags |= IOP_XATTR;
147 i_uid_write(inode, 0);
148 i_gid_write(inode, 0);
149 atomic_set(&inode->i_writecount, 0);
150 inode->i_size = 0;
151 inode->i_write_hint = WRITE_LIFE_NOT_SET;
152 inode->i_blocks = 0;
153 inode->i_bytes = 0;
154 inode->i_generation = 0;
155 inode->i_pipe = NULL;
156 inode->i_bdev = NULL;
157 inode->i_cdev = NULL;
158 inode->i_link = NULL;
159 inode->i_dir_seq = 0;
160 inode->i_rdev = 0;
161 inode->dirtied_when = 0;
162
163#ifdef CONFIG_CGROUP_WRITEBACK
164 inode->i_wb_frn_winner = 0;
165 inode->i_wb_frn_avg_time = 0;
166 inode->i_wb_frn_history = 0;
167#endif
168
169 if (security_inode_alloc(inode))
170 goto out;
171 spin_lock_init(&inode->i_lock);
172 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
173
174 init_rwsem(&inode->i_rwsem);
175 lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key);
176
177 atomic_set(&inode->i_dio_count, 0);
178
179 mapping->a_ops = &empty_aops;
180 mapping->host = inode;
181 mapping->flags = 0;
182 mapping->wb_err = 0;
183 atomic_set(&mapping->i_mmap_writable, 0);
184#ifdef CONFIG_READ_ONLY_THP_FOR_FS
185 atomic_set(&mapping->nr_thps, 0);
186#endif
187 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
188 mapping->private_data = NULL;
189 mapping->writeback_index = 0;
190 inode->i_private = NULL;
191 inode->i_mapping = mapping;
192 INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
193#ifdef CONFIG_FS_POSIX_ACL
194 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
195#endif
196
197#ifdef CONFIG_FSNOTIFY
198 inode->i_fsnotify_mask = 0;
199#endif
200 inode->i_flctx = NULL;
201 this_cpu_inc(nr_inodes);
202
203 return 0;
204out:
205 return -ENOMEM;
206}
207EXPORT_SYMBOL(inode_init_always);
208
209void free_inode_nonrcu(struct inode *inode)
210{
211 kmem_cache_free(inode_cachep, inode);
212}
213EXPORT_SYMBOL(free_inode_nonrcu);
214
215static void i_callback(struct rcu_head *head)
216{
217 struct inode *inode = container_of(head, struct inode, i_rcu);
218 if (inode->free_inode)
219 inode->free_inode(inode);
220 else
221 free_inode_nonrcu(inode);
222}
223
224static struct inode *alloc_inode(struct super_block *sb)
225{
226 const struct super_operations *ops = sb->s_op;
227 struct inode *inode;
228
229 if (ops->alloc_inode)
230 inode = ops->alloc_inode(sb);
231 else
232 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
233
234 if (!inode)
235 return NULL;
236
237 if (unlikely(inode_init_always(sb, inode))) {
238 if (ops->destroy_inode) {
239 ops->destroy_inode(inode);
240 if (!ops->free_inode)
241 return NULL;
242 }
243 inode->free_inode = ops->free_inode;
244 i_callback(&inode->i_rcu);
245 return NULL;
246 }
247
248 return inode;
249}
250
251void __destroy_inode(struct inode *inode)
252{
253 BUG_ON(inode_has_buffers(inode));
254 inode_detach_wb(inode);
255 security_inode_free(inode);
256 fsnotify_inode_delete(inode);
257 locks_free_lock_context(inode);
258 if (!inode->i_nlink) {
259 WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
260 atomic_long_dec(&inode->i_sb->s_remove_count);
261 }
262
263#ifdef CONFIG_FS_POSIX_ACL
264 if (inode->i_acl && !is_uncached_acl(inode->i_acl))
265 posix_acl_release(inode->i_acl);
266 if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl))
267 posix_acl_release(inode->i_default_acl);
268#endif
269 this_cpu_dec(nr_inodes);
270}
271EXPORT_SYMBOL(__destroy_inode);
272
273static void destroy_inode(struct inode *inode)
274{
275 const struct super_operations *ops = inode->i_sb->s_op;
276
277 BUG_ON(!list_empty(&inode->i_lru));
278 __destroy_inode(inode);
279 if (ops->destroy_inode) {
280 ops->destroy_inode(inode);
281 if (!ops->free_inode)
282 return;
283 }
284 inode->free_inode = ops->free_inode;
285 call_rcu(&inode->i_rcu, i_callback);
286}
287
288/**
289 * drop_nlink - directly drop an inode's link count
290 * @inode: inode
291 *
292 * This is a low-level filesystem helper to replace any
293 * direct filesystem manipulation of i_nlink. In cases
294 * where we are attempting to track writes to the
295 * filesystem, a decrement to zero means an imminent
296 * write when the file is truncated and actually unlinked
297 * on the filesystem.
298 */
299void drop_nlink(struct inode *inode)
300{
301 WARN_ON(inode->i_nlink == 0);
302 inode->__i_nlink--;
303 if (!inode->i_nlink)
304 atomic_long_inc(&inode->i_sb->s_remove_count);
305}
306EXPORT_SYMBOL(drop_nlink);
307
308/**
309 * clear_nlink - directly zero an inode's link count
310 * @inode: inode
311 *
312 * This is a low-level filesystem helper to replace any
313 * direct filesystem manipulation of i_nlink. See
314 * drop_nlink() for why we care about i_nlink hitting zero.
315 */
316void clear_nlink(struct inode *inode)
317{
318 if (inode->i_nlink) {
319 inode->__i_nlink = 0;
320 atomic_long_inc(&inode->i_sb->s_remove_count);
321 }
322}
323EXPORT_SYMBOL(clear_nlink);
324
325/**
326 * set_nlink - directly set an inode's link count
327 * @inode: inode
328 * @nlink: new nlink (should be non-zero)
329 *
330 * This is a low-level filesystem helper to replace any
331 * direct filesystem manipulation of i_nlink.
332 */
333void set_nlink(struct inode *inode, unsigned int nlink)
334{
335 if (!nlink) {
336 clear_nlink(inode);
337 } else {
338 /* Yes, some filesystems do change nlink from zero to one */
339 if (inode->i_nlink == 0)
340 atomic_long_dec(&inode->i_sb->s_remove_count);
341
342 inode->__i_nlink = nlink;
343 }
344}
345EXPORT_SYMBOL(set_nlink);
346
347/**
348 * inc_nlink - directly increment an inode's link count
349 * @inode: inode
350 *
351 * This is a low-level filesystem helper to replace any
352 * direct filesystem manipulation of i_nlink. Currently,
353 * it is only here for parity with dec_nlink().
354 */
355void inc_nlink(struct inode *inode)
356{
357 if (unlikely(inode->i_nlink == 0)) {
358 WARN_ON(!(inode->i_state & I_LINKABLE));
359 atomic_long_dec(&inode->i_sb->s_remove_count);
360 }
361
362 inode->__i_nlink++;
363}
364EXPORT_SYMBOL(inc_nlink);
365
366static void __address_space_init_once(struct address_space *mapping)
367{
368 xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT);
369 init_rwsem(&mapping->i_mmap_rwsem);
370 INIT_LIST_HEAD(&mapping->private_list);
371 spin_lock_init(&mapping->private_lock);
372 mapping->i_mmap = RB_ROOT_CACHED;
373}
374
375void address_space_init_once(struct address_space *mapping)
376{
377 memset(mapping, 0, sizeof(*mapping));
378 __address_space_init_once(mapping);
379}
380EXPORT_SYMBOL(address_space_init_once);
381
382/*
383 * These are initializations that only need to be done
384 * once, because the fields are idempotent across use
385 * of the inode, so let the slab aware of that.
386 */
387void inode_init_once(struct inode *inode)
388{
389 memset(inode, 0, sizeof(*inode));
390 INIT_HLIST_NODE(&inode->i_hash);
391 INIT_LIST_HEAD(&inode->i_devices);
392 INIT_LIST_HEAD(&inode->i_io_list);
393 INIT_LIST_HEAD(&inode->i_wb_list);
394 INIT_LIST_HEAD(&inode->i_lru);
395 __address_space_init_once(&inode->i_data);
396 i_size_ordered_init(inode);
397}
398EXPORT_SYMBOL(inode_init_once);
399
400static void init_once(void *foo)
401{
402 struct inode *inode = (struct inode *) foo;
403
404 inode_init_once(inode);
405}
406
407/*
408 * inode->i_lock must be held
409 */
410void __iget(struct inode *inode)
411{
412 atomic_inc(&inode->i_count);
413}
414
415/*
416 * get additional reference to inode; caller must already hold one.
417 */
418void ihold(struct inode *inode)
419{
420 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
421}
422EXPORT_SYMBOL(ihold);
423
424static void inode_lru_list_add(struct inode *inode)
425{
426 if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
427 this_cpu_inc(nr_unused);
428 else
429 inode->i_state |= I_REFERENCED;
430}
431
432/*
433 * Add inode to LRU if needed (inode is unused and clean).
434 *
435 * Needs inode->i_lock held.
436 */
437void inode_add_lru(struct inode *inode)
438{
439 if (!(inode->i_state & (I_DIRTY_ALL | I_SYNC |
440 I_FREEING | I_WILL_FREE)) &&
441 !atomic_read(&inode->i_count) && inode->i_sb->s_flags & SB_ACTIVE)
442 inode_lru_list_add(inode);
443}
444
445
446static void inode_lru_list_del(struct inode *inode)
447{
448
449 if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
450 this_cpu_dec(nr_unused);
451}
452
453/**
454 * inode_sb_list_add - add inode to the superblock list of inodes
455 * @inode: inode to add
456 */
457void inode_sb_list_add(struct inode *inode)
458{
459 spin_lock(&inode->i_sb->s_inode_list_lock);
460 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
461 spin_unlock(&inode->i_sb->s_inode_list_lock);
462}
463EXPORT_SYMBOL_GPL(inode_sb_list_add);
464
465static inline void inode_sb_list_del(struct inode *inode)
466{
467 if (!list_empty(&inode->i_sb_list)) {
468 spin_lock(&inode->i_sb->s_inode_list_lock);
469 list_del_init(&inode->i_sb_list);
470 spin_unlock(&inode->i_sb->s_inode_list_lock);
471 }
472}
473
474static unsigned long hash(struct super_block *sb, unsigned long hashval)
475{
476 unsigned long tmp;
477
478 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
479 L1_CACHE_BYTES;
480 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
481 return tmp & i_hash_mask;
482}
483
484/**
485 * __insert_inode_hash - hash an inode
486 * @inode: unhashed inode
487 * @hashval: unsigned long value used to locate this object in the
488 * inode_hashtable.
489 *
490 * Add an inode to the inode hash for this superblock.
491 */
492void __insert_inode_hash(struct inode *inode, unsigned long hashval)
493{
494 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
495
496 spin_lock(&inode_hash_lock);
497 spin_lock(&inode->i_lock);
498 hlist_add_head(&inode->i_hash, b);
499 spin_unlock(&inode->i_lock);
500 spin_unlock(&inode_hash_lock);
501}
502EXPORT_SYMBOL(__insert_inode_hash);
503
504/**
505 * __remove_inode_hash - remove an inode from the hash
506 * @inode: inode to unhash
507 *
508 * Remove an inode from the superblock.
509 */
510void __remove_inode_hash(struct inode *inode)
511{
512 spin_lock(&inode_hash_lock);
513 spin_lock(&inode->i_lock);
514 hlist_del_init(&inode->i_hash);
515 spin_unlock(&inode->i_lock);
516 spin_unlock(&inode_hash_lock);
517}
518EXPORT_SYMBOL(__remove_inode_hash);
519
520void clear_inode(struct inode *inode)
521{
522 /*
523 * We have to cycle the i_pages lock here because reclaim can be in the
524 * process of removing the last page (in __delete_from_page_cache())
525 * and we must not free the mapping under it.
526 */
527 xa_lock_irq(&inode->i_data.i_pages);
528 BUG_ON(inode->i_data.nrpages);
529 BUG_ON(inode->i_data.nrexceptional);
530 xa_unlock_irq(&inode->i_data.i_pages);
531 BUG_ON(!list_empty(&inode->i_data.private_list));
532 BUG_ON(!(inode->i_state & I_FREEING));
533 BUG_ON(inode->i_state & I_CLEAR);
534 BUG_ON(!list_empty(&inode->i_wb_list));
535 /* don't need i_lock here, no concurrent mods to i_state */
536 inode->i_state = I_FREEING | I_CLEAR;
537}
538EXPORT_SYMBOL(clear_inode);
539
540/*
541 * Free the inode passed in, removing it from the lists it is still connected
542 * to. We remove any pages still attached to the inode and wait for any IO that
543 * is still in progress before finally destroying the inode.
544 *
545 * An inode must already be marked I_FREEING so that we avoid the inode being
546 * moved back onto lists if we race with other code that manipulates the lists
547 * (e.g. writeback_single_inode). The caller is responsible for setting this.
548 *
549 * An inode must already be removed from the LRU list before being evicted from
550 * the cache. This should occur atomically with setting the I_FREEING state
551 * flag, so no inodes here should ever be on the LRU when being evicted.
552 */
553static void evict(struct inode *inode)
554{
555 const struct super_operations *op = inode->i_sb->s_op;
556
557 BUG_ON(!(inode->i_state & I_FREEING));
558 BUG_ON(!list_empty(&inode->i_lru));
559
560 if (!list_empty(&inode->i_io_list))
561 inode_io_list_del(inode);
562
563 inode_sb_list_del(inode);
564
565 /*
566 * Wait for flusher thread to be done with the inode so that filesystem
567 * does not start destroying it while writeback is still running. Since
568 * the inode has I_FREEING set, flusher thread won't start new work on
569 * the inode. We just have to wait for running writeback to finish.
570 */
571 inode_wait_for_writeback(inode);
572
573 if (op->evict_inode) {
574 op->evict_inode(inode);
575 } else {
576 truncate_inode_pages_final(&inode->i_data);
577 clear_inode(inode);
578 }
579 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
580 bd_forget(inode);
581 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
582 cd_forget(inode);
583
584 remove_inode_hash(inode);
585
586 spin_lock(&inode->i_lock);
587 wake_up_bit(&inode->i_state, __I_NEW);
588 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
589 spin_unlock(&inode->i_lock);
590
591 destroy_inode(inode);
592}
593
594/*
595 * dispose_list - dispose of the contents of a local list
596 * @head: the head of the list to free
597 *
598 * Dispose-list gets a local list with local inodes in it, so it doesn't
599 * need to worry about list corruption and SMP locks.
600 */
601static void dispose_list(struct list_head *head)
602{
603 while (!list_empty(head)) {
604 struct inode *inode;
605
606 inode = list_first_entry(head, struct inode, i_lru);
607 list_del_init(&inode->i_lru);
608
609 evict(inode);
610 cond_resched();
611 }
612}
613
614/**
615 * evict_inodes - evict all evictable inodes for a superblock
616 * @sb: superblock to operate on
617 *
618 * Make sure that no inodes with zero refcount are retained. This is
619 * called by superblock shutdown after having SB_ACTIVE flag removed,
620 * so any inode reaching zero refcount during or after that call will
621 * be immediately evicted.
622 */
623void evict_inodes(struct super_block *sb)
624{
625 struct inode *inode, *next;
626 LIST_HEAD(dispose);
627
628again:
629 spin_lock(&sb->s_inode_list_lock);
630 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
631 if (atomic_read(&inode->i_count))
632 continue;
633
634 spin_lock(&inode->i_lock);
635 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
636 spin_unlock(&inode->i_lock);
637 continue;
638 }
639
640 inode->i_state |= I_FREEING;
641 inode_lru_list_del(inode);
642 spin_unlock(&inode->i_lock);
643 list_add(&inode->i_lru, &dispose);
644
645 /*
646 * We can have a ton of inodes to evict at unmount time given
647 * enough memory, check to see if we need to go to sleep for a
648 * bit so we don't livelock.
649 */
650 if (need_resched()) {
651 spin_unlock(&sb->s_inode_list_lock);
652 cond_resched();
653 dispose_list(&dispose);
654 goto again;
655 }
656 }
657 spin_unlock(&sb->s_inode_list_lock);
658
659 dispose_list(&dispose);
660}
661EXPORT_SYMBOL_GPL(evict_inodes);
662
663/**
664 * invalidate_inodes - attempt to free all inodes on a superblock
665 * @sb: superblock to operate on
666 * @kill_dirty: flag to guide handling of dirty inodes
667 *
668 * Attempts to free all inodes for a given superblock. If there were any
669 * busy inodes return a non-zero value, else zero.
670 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
671 * them as busy.
672 */
673int invalidate_inodes(struct super_block *sb, bool kill_dirty)
674{
675 int busy = 0;
676 struct inode *inode, *next;
677 LIST_HEAD(dispose);
678
679 spin_lock(&sb->s_inode_list_lock);
680 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
681 spin_lock(&inode->i_lock);
682 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
683 spin_unlock(&inode->i_lock);
684 continue;
685 }
686 if (inode->i_state & I_DIRTY_ALL && !kill_dirty) {
687 spin_unlock(&inode->i_lock);
688 busy = 1;
689 continue;
690 }
691 if (atomic_read(&inode->i_count)) {
692 spin_unlock(&inode->i_lock);
693 busy = 1;
694 continue;
695 }
696
697 inode->i_state |= I_FREEING;
698 inode_lru_list_del(inode);
699 spin_unlock(&inode->i_lock);
700 list_add(&inode->i_lru, &dispose);
701 }
702 spin_unlock(&sb->s_inode_list_lock);
703
704 dispose_list(&dispose);
705
706 return busy;
707}
708
709/*
710 * Isolate the inode from the LRU in preparation for freeing it.
711 *
712 * Any inodes which are pinned purely because of attached pagecache have their
713 * pagecache removed. If the inode has metadata buffers attached to
714 * mapping->private_list then try to remove them.
715 *
716 * If the inode has the I_REFERENCED flag set, then it means that it has been
717 * used recently - the flag is set in iput_final(). When we encounter such an
718 * inode, clear the flag and move it to the back of the LRU so it gets another
719 * pass through the LRU before it gets reclaimed. This is necessary because of
720 * the fact we are doing lazy LRU updates to minimise lock contention so the
721 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
722 * with this flag set because they are the inodes that are out of order.
723 */
724static enum lru_status inode_lru_isolate(struct list_head *item,
725 struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
726{
727 struct list_head *freeable = arg;
728 struct inode *inode = container_of(item, struct inode, i_lru);
729
730 /*
731 * we are inverting the lru lock/inode->i_lock here, so use a trylock.
732 * If we fail to get the lock, just skip it.
733 */
734 if (!spin_trylock(&inode->i_lock))
735 return LRU_SKIP;
736
737 /*
738 * Referenced or dirty inodes are still in use. Give them another pass
739 * through the LRU as we canot reclaim them now.
740 */
741 if (atomic_read(&inode->i_count) ||
742 (inode->i_state & ~I_REFERENCED)) {
743 list_lru_isolate(lru, &inode->i_lru);
744 spin_unlock(&inode->i_lock);
745 this_cpu_dec(nr_unused);
746 return LRU_REMOVED;
747 }
748
749 /* recently referenced inodes get one more pass */
750 if (inode->i_state & I_REFERENCED) {
751 inode->i_state &= ~I_REFERENCED;
752 spin_unlock(&inode->i_lock);
753 return LRU_ROTATE;
754 }
755
756 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
757 __iget(inode);
758 spin_unlock(&inode->i_lock);
759 spin_unlock(lru_lock);
760 if (remove_inode_buffers(inode)) {
761 unsigned long reap;
762 reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
763 if (current_is_kswapd())
764 __count_vm_events(KSWAPD_INODESTEAL, reap);
765 else
766 __count_vm_events(PGINODESTEAL, reap);
767 if (current->reclaim_state)
768 current->reclaim_state->reclaimed_slab += reap;
769 }
770 iput(inode);
771 spin_lock(lru_lock);
772 return LRU_RETRY;
773 }
774
775 WARN_ON(inode->i_state & I_NEW);
776 inode->i_state |= I_FREEING;
777 list_lru_isolate_move(lru, &inode->i_lru, freeable);
778 spin_unlock(&inode->i_lock);
779
780 this_cpu_dec(nr_unused);
781 return LRU_REMOVED;
782}
783
784/*
785 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
786 * This is called from the superblock shrinker function with a number of inodes
787 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
788 * then are freed outside inode_lock by dispose_list().
789 */
790long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
791{
792 LIST_HEAD(freeable);
793 long freed;
794
795 freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
796 inode_lru_isolate, &freeable);
797 dispose_list(&freeable);
798 return freed;
799}
800
801static void __wait_on_freeing_inode(struct inode *inode);
802/*
803 * Called with the inode lock held.
804 */
805static struct inode *find_inode(struct super_block *sb,
806 struct hlist_head *head,
807 int (*test)(struct inode *, void *),
808 void *data)
809{
810 struct inode *inode = NULL;
811
812repeat:
813 hlist_for_each_entry(inode, head, i_hash) {
814 if (inode->i_sb != sb)
815 continue;
816 if (!test(inode, data))
817 continue;
818 spin_lock(&inode->i_lock);
819 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
820 __wait_on_freeing_inode(inode);
821 goto repeat;
822 }
823 if (unlikely(inode->i_state & I_CREATING)) {
824 spin_unlock(&inode->i_lock);
825 return ERR_PTR(-ESTALE);
826 }
827 __iget(inode);
828 spin_unlock(&inode->i_lock);
829 return inode;
830 }
831 return NULL;
832}
833
834/*
835 * find_inode_fast is the fast path version of find_inode, see the comment at
836 * iget_locked for details.
837 */
838static struct inode *find_inode_fast(struct super_block *sb,
839 struct hlist_head *head, unsigned long ino)
840{
841 struct inode *inode = NULL;
842
843repeat:
844 hlist_for_each_entry(inode, head, i_hash) {
845 if (inode->i_ino != ino)
846 continue;
847 if (inode->i_sb != sb)
848 continue;
849 spin_lock(&inode->i_lock);
850 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
851 __wait_on_freeing_inode(inode);
852 goto repeat;
853 }
854 if (unlikely(inode->i_state & I_CREATING)) {
855 spin_unlock(&inode->i_lock);
856 return ERR_PTR(-ESTALE);
857 }
858 __iget(inode);
859 spin_unlock(&inode->i_lock);
860 return inode;
861 }
862 return NULL;
863}
864
865/*
866 * Each cpu owns a range of LAST_INO_BATCH numbers.
867 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
868 * to renew the exhausted range.
869 *
870 * This does not significantly increase overflow rate because every CPU can
871 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
872 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
873 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
874 * overflow rate by 2x, which does not seem too significant.
875 *
876 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
877 * error if st_ino won't fit in target struct field. Use 32bit counter
878 * here to attempt to avoid that.
879 */
880#define LAST_INO_BATCH 1024
881static DEFINE_PER_CPU(unsigned int, last_ino);
882
883unsigned int get_next_ino(void)
884{
885 unsigned int *p = &get_cpu_var(last_ino);
886 unsigned int res = *p;
887
888#ifdef CONFIG_SMP
889 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
890 static atomic_t shared_last_ino;
891 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
892
893 res = next - LAST_INO_BATCH;
894 }
895#endif
896
897 res++;
898 /* get_next_ino should not provide a 0 inode number */
899 if (unlikely(!res))
900 res++;
901 *p = res;
902 put_cpu_var(last_ino);
903 return res;
904}
905EXPORT_SYMBOL(get_next_ino);
906
907/**
908 * new_inode_pseudo - obtain an inode
909 * @sb: superblock
910 *
911 * Allocates a new inode for given superblock.
912 * Inode wont be chained in superblock s_inodes list
913 * This means :
914 * - fs can't be unmount
915 * - quotas, fsnotify, writeback can't work
916 */
917struct inode *new_inode_pseudo(struct super_block *sb)
918{
919 struct inode *inode = alloc_inode(sb);
920
921 if (inode) {
922 spin_lock(&inode->i_lock);
923 inode->i_state = 0;
924 spin_unlock(&inode->i_lock);
925 INIT_LIST_HEAD(&inode->i_sb_list);
926 }
927 return inode;
928}
929
930/**
931 * new_inode - obtain an inode
932 * @sb: superblock
933 *
934 * Allocates a new inode for given superblock. The default gfp_mask
935 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
936 * If HIGHMEM pages are unsuitable or it is known that pages allocated
937 * for the page cache are not reclaimable or migratable,
938 * mapping_set_gfp_mask() must be called with suitable flags on the
939 * newly created inode's mapping
940 *
941 */
942struct inode *new_inode(struct super_block *sb)
943{
944 struct inode *inode;
945
946 spin_lock_prefetch(&sb->s_inode_list_lock);
947
948 inode = new_inode_pseudo(sb);
949 if (inode)
950 inode_sb_list_add(inode);
951 return inode;
952}
953EXPORT_SYMBOL(new_inode);
954
955#ifdef CONFIG_DEBUG_LOCK_ALLOC
956void lockdep_annotate_inode_mutex_key(struct inode *inode)
957{
958 if (S_ISDIR(inode->i_mode)) {
959 struct file_system_type *type = inode->i_sb->s_type;
960
961 /* Set new key only if filesystem hasn't already changed it */
962 if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) {
963 /*
964 * ensure nobody is actually holding i_mutex
965 */
966 // mutex_destroy(&inode->i_mutex);
967 init_rwsem(&inode->i_rwsem);
968 lockdep_set_class(&inode->i_rwsem,
969 &type->i_mutex_dir_key);
970 }
971 }
972}
973EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
974#endif
975
976/**
977 * unlock_new_inode - clear the I_NEW state and wake up any waiters
978 * @inode: new inode to unlock
979 *
980 * Called when the inode is fully initialised to clear the new state of the
981 * inode and wake up anyone waiting for the inode to finish initialisation.
982 */
983void unlock_new_inode(struct inode *inode)
984{
985 lockdep_annotate_inode_mutex_key(inode);
986 spin_lock(&inode->i_lock);
987 WARN_ON(!(inode->i_state & I_NEW));
988 inode->i_state &= ~I_NEW & ~I_CREATING;
989 smp_mb();
990 wake_up_bit(&inode->i_state, __I_NEW);
991 spin_unlock(&inode->i_lock);
992}
993EXPORT_SYMBOL(unlock_new_inode);
994
995void discard_new_inode(struct inode *inode)
996{
997 lockdep_annotate_inode_mutex_key(inode);
998 spin_lock(&inode->i_lock);
999 WARN_ON(!(inode->i_state & I_NEW));
1000 inode->i_state &= ~I_NEW;
1001 smp_mb();
1002 wake_up_bit(&inode->i_state, __I_NEW);
1003 spin_unlock(&inode->i_lock);
1004 iput(inode);
1005}
1006EXPORT_SYMBOL(discard_new_inode);
1007
1008/**
1009 * lock_two_nondirectories - take two i_mutexes on non-directory objects
1010 *
1011 * Lock any non-NULL argument that is not a directory.
1012 * Zero, one or two objects may be locked by this function.
1013 *
1014 * @inode1: first inode to lock
1015 * @inode2: second inode to lock
1016 */
1017void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
1018{
1019 if (inode1 > inode2)
1020 swap(inode1, inode2);
1021
1022 if (inode1 && !S_ISDIR(inode1->i_mode))
1023 inode_lock(inode1);
1024 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
1025 inode_lock_nested(inode2, I_MUTEX_NONDIR2);
1026}
1027EXPORT_SYMBOL(lock_two_nondirectories);
1028
1029/**
1030 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
1031 * @inode1: first inode to unlock
1032 * @inode2: second inode to unlock
1033 */
1034void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
1035{
1036 if (inode1 && !S_ISDIR(inode1->i_mode))
1037 inode_unlock(inode1);
1038 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
1039 inode_unlock(inode2);
1040}
1041EXPORT_SYMBOL(unlock_two_nondirectories);
1042
1043/**
1044 * inode_insert5 - obtain an inode from a mounted file system
1045 * @inode: pre-allocated inode to use for insert to cache
1046 * @hashval: hash value (usually inode number) to get
1047 * @test: callback used for comparisons between inodes
1048 * @set: callback used to initialize a new struct inode
1049 * @data: opaque data pointer to pass to @test and @set
1050 *
1051 * Search for the inode specified by @hashval and @data in the inode cache,
1052 * and if present it is return it with an increased reference count. This is
1053 * a variant of iget5_locked() for callers that don't want to fail on memory
1054 * allocation of inode.
1055 *
1056 * If the inode is not in cache, insert the pre-allocated inode to cache and
1057 * return it locked, hashed, and with the I_NEW flag set. The file system gets
1058 * to fill it in before unlocking it via unlock_new_inode().
1059 *
1060 * Note both @test and @set are called with the inode_hash_lock held, so can't
1061 * sleep.
1062 */
1063struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
1064 int (*test)(struct inode *, void *),
1065 int (*set)(struct inode *, void *), void *data)
1066{
1067 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
1068 struct inode *old;
1069 bool creating = inode->i_state & I_CREATING;
1070
1071again:
1072 spin_lock(&inode_hash_lock);
1073 old = find_inode(inode->i_sb, head, test, data);
1074 if (unlikely(old)) {
1075 /*
1076 * Uhhuh, somebody else created the same inode under us.
1077 * Use the old inode instead of the preallocated one.
1078 */
1079 spin_unlock(&inode_hash_lock);
1080 if (IS_ERR(old))
1081 return NULL;
1082 wait_on_inode(old);
1083 if (unlikely(inode_unhashed(old))) {
1084 iput(old);
1085 goto again;
1086 }
1087 return old;
1088 }
1089
1090 if (set && unlikely(set(inode, data))) {
1091 inode = NULL;
1092 goto unlock;
1093 }
1094
1095 /*
1096 * Return the locked inode with I_NEW set, the
1097 * caller is responsible for filling in the contents
1098 */
1099 spin_lock(&inode->i_lock);
1100 inode->i_state |= I_NEW;
1101 hlist_add_head(&inode->i_hash, head);
1102 spin_unlock(&inode->i_lock);
1103 if (!creating)
1104 inode_sb_list_add(inode);
1105unlock:
1106 spin_unlock(&inode_hash_lock);
1107
1108 return inode;
1109}
1110EXPORT_SYMBOL(inode_insert5);
1111
1112/**
1113 * iget5_locked - obtain an inode from a mounted file system
1114 * @sb: super block of file system
1115 * @hashval: hash value (usually inode number) to get
1116 * @test: callback used for comparisons between inodes
1117 * @set: callback used to initialize a new struct inode
1118 * @data: opaque data pointer to pass to @test and @set
1119 *
1120 * Search for the inode specified by @hashval and @data in the inode cache,
1121 * and if present it is return it with an increased reference count. This is
1122 * a generalized version of iget_locked() for file systems where the inode
1123 * number is not sufficient for unique identification of an inode.
1124 *
1125 * If the inode is not in cache, allocate a new inode and return it locked,
1126 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1127 * before unlocking it via unlock_new_inode().
1128 *
1129 * Note both @test and @set are called with the inode_hash_lock held, so can't
1130 * sleep.
1131 */
1132struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
1133 int (*test)(struct inode *, void *),
1134 int (*set)(struct inode *, void *), void *data)
1135{
1136 struct inode *inode = ilookup5(sb, hashval, test, data);
1137
1138 if (!inode) {
1139 struct inode *new = alloc_inode(sb);
1140
1141 if (new) {
1142 new->i_state = 0;
1143 inode = inode_insert5(new, hashval, test, set, data);
1144 if (unlikely(inode != new))
1145 destroy_inode(new);
1146 }
1147 }
1148 return inode;
1149}
1150EXPORT_SYMBOL(iget5_locked);
1151
1152/**
1153 * iget_locked - obtain an inode from a mounted file system
1154 * @sb: super block of file system
1155 * @ino: inode number to get
1156 *
1157 * Search for the inode specified by @ino in the inode cache and if present
1158 * return it with an increased reference count. This is for file systems
1159 * where the inode number is sufficient for unique identification of an inode.
1160 *
1161 * If the inode is not in cache, allocate a new inode and return it locked,
1162 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1163 * before unlocking it via unlock_new_inode().
1164 */
1165struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1166{
1167 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1168 struct inode *inode;
1169again:
1170 spin_lock(&inode_hash_lock);
1171 inode = find_inode_fast(sb, head, ino);
1172 spin_unlock(&inode_hash_lock);
1173 if (inode) {
1174 if (IS_ERR(inode))
1175 return NULL;
1176 wait_on_inode(inode);
1177 if (unlikely(inode_unhashed(inode))) {
1178 iput(inode);
1179 goto again;
1180 }
1181 return inode;
1182 }
1183
1184 inode = alloc_inode(sb);
1185 if (inode) {
1186 struct inode *old;
1187
1188 spin_lock(&inode_hash_lock);
1189 /* We released the lock, so.. */
1190 old = find_inode_fast(sb, head, ino);
1191 if (!old) {
1192 inode->i_ino = ino;
1193 spin_lock(&inode->i_lock);
1194 inode->i_state = I_NEW;
1195 hlist_add_head(&inode->i_hash, head);
1196 spin_unlock(&inode->i_lock);
1197 inode_sb_list_add(inode);
1198 spin_unlock(&inode_hash_lock);
1199
1200 /* Return the locked inode with I_NEW set, the
1201 * caller is responsible for filling in the contents
1202 */
1203 return inode;
1204 }
1205
1206 /*
1207 * Uhhuh, somebody else created the same inode under
1208 * us. Use the old inode instead of the one we just
1209 * allocated.
1210 */
1211 spin_unlock(&inode_hash_lock);
1212 destroy_inode(inode);
1213 if (IS_ERR(old))
1214 return NULL;
1215 inode = old;
1216 wait_on_inode(inode);
1217 if (unlikely(inode_unhashed(inode))) {
1218 iput(inode);
1219 goto again;
1220 }
1221 }
1222 return inode;
1223}
1224EXPORT_SYMBOL(iget_locked);
1225
1226/*
1227 * search the inode cache for a matching inode number.
1228 * If we find one, then the inode number we are trying to
1229 * allocate is not unique and so we should not use it.
1230 *
1231 * Returns 1 if the inode number is unique, 0 if it is not.
1232 */
1233static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1234{
1235 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1236 struct inode *inode;
1237
1238 spin_lock(&inode_hash_lock);
1239 hlist_for_each_entry(inode, b, i_hash) {
1240 if (inode->i_ino == ino && inode->i_sb == sb) {
1241 spin_unlock(&inode_hash_lock);
1242 return 0;
1243 }
1244 }
1245 spin_unlock(&inode_hash_lock);
1246
1247 return 1;
1248}
1249
1250/**
1251 * iunique - get a unique inode number
1252 * @sb: superblock
1253 * @max_reserved: highest reserved inode number
1254 *
1255 * Obtain an inode number that is unique on the system for a given
1256 * superblock. This is used by file systems that have no natural
1257 * permanent inode numbering system. An inode number is returned that
1258 * is higher than the reserved limit but unique.
1259 *
1260 * BUGS:
1261 * With a large number of inodes live on the file system this function
1262 * currently becomes quite slow.
1263 */
1264ino_t iunique(struct super_block *sb, ino_t max_reserved)
1265{
1266 /*
1267 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1268 * error if st_ino won't fit in target struct field. Use 32bit counter
1269 * here to attempt to avoid that.
1270 */
1271 static DEFINE_SPINLOCK(iunique_lock);
1272 static unsigned int counter;
1273 ino_t res;
1274
1275 spin_lock(&iunique_lock);
1276 do {
1277 if (counter <= max_reserved)
1278 counter = max_reserved + 1;
1279 res = counter++;
1280 } while (!test_inode_iunique(sb, res));
1281 spin_unlock(&iunique_lock);
1282
1283 return res;
1284}
1285EXPORT_SYMBOL(iunique);
1286
1287struct inode *igrab(struct inode *inode)
1288{
1289 spin_lock(&inode->i_lock);
1290 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1291 __iget(inode);
1292 spin_unlock(&inode->i_lock);
1293 } else {
1294 spin_unlock(&inode->i_lock);
1295 /*
1296 * Handle the case where s_op->clear_inode is not been
1297 * called yet, and somebody is calling igrab
1298 * while the inode is getting freed.
1299 */
1300 inode = NULL;
1301 }
1302 return inode;
1303}
1304EXPORT_SYMBOL(igrab);
1305
1306/**
1307 * ilookup5_nowait - search for an inode in the inode cache
1308 * @sb: super block of file system to search
1309 * @hashval: hash value (usually inode number) to search for
1310 * @test: callback used for comparisons between inodes
1311 * @data: opaque data pointer to pass to @test
1312 *
1313 * Search for the inode specified by @hashval and @data in the inode cache.
1314 * If the inode is in the cache, the inode is returned with an incremented
1315 * reference count.
1316 *
1317 * Note: I_NEW is not waited upon so you have to be very careful what you do
1318 * with the returned inode. You probably should be using ilookup5() instead.
1319 *
1320 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1321 */
1322struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1323 int (*test)(struct inode *, void *), void *data)
1324{
1325 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1326 struct inode *inode;
1327
1328 spin_lock(&inode_hash_lock);
1329 inode = find_inode(sb, head, test, data);
1330 spin_unlock(&inode_hash_lock);
1331
1332 return IS_ERR(inode) ? NULL : inode;
1333}
1334EXPORT_SYMBOL(ilookup5_nowait);
1335
1336/**
1337 * ilookup5 - search for an inode in the inode cache
1338 * @sb: super block of file system to search
1339 * @hashval: hash value (usually inode number) to search for
1340 * @test: callback used for comparisons between inodes
1341 * @data: opaque data pointer to pass to @test
1342 *
1343 * Search for the inode specified by @hashval and @data in the inode cache,
1344 * and if the inode is in the cache, return the inode with an incremented
1345 * reference count. Waits on I_NEW before returning the inode.
1346 * returned with an incremented reference count.
1347 *
1348 * This is a generalized version of ilookup() for file systems where the
1349 * inode number is not sufficient for unique identification of an inode.
1350 *
1351 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1352 */
1353struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1354 int (*test)(struct inode *, void *), void *data)
1355{
1356 struct inode *inode;
1357again:
1358 inode = ilookup5_nowait(sb, hashval, test, data);
1359 if (inode) {
1360 wait_on_inode(inode);
1361 if (unlikely(inode_unhashed(inode))) {
1362 iput(inode);
1363 goto again;
1364 }
1365 }
1366 return inode;
1367}
1368EXPORT_SYMBOL(ilookup5);
1369
1370/**
1371 * ilookup - search for an inode in the inode cache
1372 * @sb: super block of file system to search
1373 * @ino: inode number to search for
1374 *
1375 * Search for the inode @ino in the inode cache, and if the inode is in the
1376 * cache, the inode is returned with an incremented reference count.
1377 */
1378struct inode *ilookup(struct super_block *sb, unsigned long ino)
1379{
1380 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1381 struct inode *inode;
1382again:
1383 spin_lock(&inode_hash_lock);
1384 inode = find_inode_fast(sb, head, ino);
1385 spin_unlock(&inode_hash_lock);
1386
1387 if (inode) {
1388 if (IS_ERR(inode))
1389 return NULL;
1390 wait_on_inode(inode);
1391 if (unlikely(inode_unhashed(inode))) {
1392 iput(inode);
1393 goto again;
1394 }
1395 }
1396 return inode;
1397}
1398EXPORT_SYMBOL(ilookup);
1399
1400/**
1401 * find_inode_nowait - find an inode in the inode cache
1402 * @sb: super block of file system to search
1403 * @hashval: hash value (usually inode number) to search for
1404 * @match: callback used for comparisons between inodes
1405 * @data: opaque data pointer to pass to @match
1406 *
1407 * Search for the inode specified by @hashval and @data in the inode
1408 * cache, where the helper function @match will return 0 if the inode
1409 * does not match, 1 if the inode does match, and -1 if the search
1410 * should be stopped. The @match function must be responsible for
1411 * taking the i_lock spin_lock and checking i_state for an inode being
1412 * freed or being initialized, and incrementing the reference count
1413 * before returning 1. It also must not sleep, since it is called with
1414 * the inode_hash_lock spinlock held.
1415 *
1416 * This is a even more generalized version of ilookup5() when the
1417 * function must never block --- find_inode() can block in
1418 * __wait_on_freeing_inode() --- or when the caller can not increment
1419 * the reference count because the resulting iput() might cause an
1420 * inode eviction. The tradeoff is that the @match funtion must be
1421 * very carefully implemented.
1422 */
1423struct inode *find_inode_nowait(struct super_block *sb,
1424 unsigned long hashval,
1425 int (*match)(struct inode *, unsigned long,
1426 void *),
1427 void *data)
1428{
1429 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1430 struct inode *inode, *ret_inode = NULL;
1431 int mval;
1432
1433 spin_lock(&inode_hash_lock);
1434 hlist_for_each_entry(inode, head, i_hash) {
1435 if (inode->i_sb != sb)
1436 continue;
1437 mval = match(inode, hashval, data);
1438 if (mval == 0)
1439 continue;
1440 if (mval == 1)
1441 ret_inode = inode;
1442 goto out;
1443 }
1444out:
1445 spin_unlock(&inode_hash_lock);
1446 return ret_inode;
1447}
1448EXPORT_SYMBOL(find_inode_nowait);
1449
1450int insert_inode_locked(struct inode *inode)
1451{
1452 struct super_block *sb = inode->i_sb;
1453 ino_t ino = inode->i_ino;
1454 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1455
1456 while (1) {
1457 struct inode *old = NULL;
1458 spin_lock(&inode_hash_lock);
1459 hlist_for_each_entry(old, head, i_hash) {
1460 if (old->i_ino != ino)
1461 continue;
1462 if (old->i_sb != sb)
1463 continue;
1464 spin_lock(&old->i_lock);
1465 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1466 spin_unlock(&old->i_lock);
1467 continue;
1468 }
1469 break;
1470 }
1471 if (likely(!old)) {
1472 spin_lock(&inode->i_lock);
1473 inode->i_state |= I_NEW | I_CREATING;
1474 hlist_add_head(&inode->i_hash, head);
1475 spin_unlock(&inode->i_lock);
1476 spin_unlock(&inode_hash_lock);
1477 return 0;
1478 }
1479 if (unlikely(old->i_state & I_CREATING)) {
1480 spin_unlock(&old->i_lock);
1481 spin_unlock(&inode_hash_lock);
1482 return -EBUSY;
1483 }
1484 __iget(old);
1485 spin_unlock(&old->i_lock);
1486 spin_unlock(&inode_hash_lock);
1487 wait_on_inode(old);
1488 if (unlikely(!inode_unhashed(old))) {
1489 iput(old);
1490 return -EBUSY;
1491 }
1492 iput(old);
1493 }
1494}
1495EXPORT_SYMBOL(insert_inode_locked);
1496
1497int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1498 int (*test)(struct inode *, void *), void *data)
1499{
1500 struct inode *old;
1501
1502 inode->i_state |= I_CREATING;
1503 old = inode_insert5(inode, hashval, test, NULL, data);
1504
1505 if (old != inode) {
1506 iput(old);
1507 return -EBUSY;
1508 }
1509 return 0;
1510}
1511EXPORT_SYMBOL(insert_inode_locked4);
1512
1513
1514int generic_delete_inode(struct inode *inode)
1515{
1516 return 1;
1517}
1518EXPORT_SYMBOL(generic_delete_inode);
1519
1520/*
1521 * Called when we're dropping the last reference
1522 * to an inode.
1523 *
1524 * Call the FS "drop_inode()" function, defaulting to
1525 * the legacy UNIX filesystem behaviour. If it tells
1526 * us to evict inode, do so. Otherwise, retain inode
1527 * in cache if fs is alive, sync and evict if fs is
1528 * shutting down.
1529 */
1530static void iput_final(struct inode *inode)
1531{
1532 struct super_block *sb = inode->i_sb;
1533 const struct super_operations *op = inode->i_sb->s_op;
1534 int drop;
1535
1536 WARN_ON(inode->i_state & I_NEW);
1537
1538 if (op->drop_inode)
1539 drop = op->drop_inode(inode);
1540 else
1541 drop = generic_drop_inode(inode);
1542
1543 if (!drop && (sb->s_flags & SB_ACTIVE)) {
1544 inode_add_lru(inode);
1545 spin_unlock(&inode->i_lock);
1546 return;
1547 }
1548
1549 if (!drop) {
1550 inode->i_state |= I_WILL_FREE;
1551 spin_unlock(&inode->i_lock);
1552 write_inode_now(inode, 1);
1553 spin_lock(&inode->i_lock);
1554 WARN_ON(inode->i_state & I_NEW);
1555 inode->i_state &= ~I_WILL_FREE;
1556 }
1557
1558 inode->i_state |= I_FREEING;
1559 if (!list_empty(&inode->i_lru))
1560 inode_lru_list_del(inode);
1561 spin_unlock(&inode->i_lock);
1562
1563 evict(inode);
1564}
1565
1566/**
1567 * iput - put an inode
1568 * @inode: inode to put
1569 *
1570 * Puts an inode, dropping its usage count. If the inode use count hits
1571 * zero, the inode is then freed and may also be destroyed.
1572 *
1573 * Consequently, iput() can sleep.
1574 */
1575void iput(struct inode *inode)
1576{
1577 if (!inode)
1578 return;
1579 BUG_ON(inode->i_state & I_CLEAR);
1580retry:
1581 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {
1582 if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) {
1583 atomic_inc(&inode->i_count);
1584 spin_unlock(&inode->i_lock);
1585 trace_writeback_lazytime_iput(inode);
1586 mark_inode_dirty_sync(inode);
1587 goto retry;
1588 }
1589 iput_final(inode);
1590 }
1591}
1592EXPORT_SYMBOL(iput);
1593
1594/**
1595 * bmap - find a block number in a file
1596 * @inode: inode of file
1597 * @block: block to find
1598 *
1599 * Returns the block number on the device holding the inode that
1600 * is the disk block number for the block of the file requested.
1601 * That is, asked for block 4 of inode 1 the function will return the
1602 * disk block relative to the disk start that holds that block of the
1603 * file.
1604 */
1605sector_t bmap(struct inode *inode, sector_t block)
1606{
1607 sector_t res = 0;
1608 if (inode->i_mapping->a_ops->bmap)
1609 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1610 return res;
1611}
1612EXPORT_SYMBOL(bmap);
1613
1614/*
1615 * With relative atime, only update atime if the previous atime is
1616 * earlier than either the ctime or mtime or if at least a day has
1617 * passed since the last atime update.
1618 */
1619static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1620 struct timespec64 now)
1621{
1622
1623 if (!(mnt->mnt_flags & MNT_RELATIME))
1624 return 1;
1625 /*
1626 * Is mtime younger than atime? If yes, update atime:
1627 */
1628 if (timespec64_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1629 return 1;
1630 /*
1631 * Is ctime younger than atime? If yes, update atime:
1632 */
1633 if (timespec64_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1634 return 1;
1635
1636 /*
1637 * Is the previous atime value older than a day? If yes,
1638 * update atime:
1639 */
1640 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1641 return 1;
1642 /*
1643 * Good, we can skip the atime update:
1644 */
1645 return 0;
1646}
1647
1648int generic_update_time(struct inode *inode, struct timespec64 *time, int flags)
1649{
1650 int iflags = I_DIRTY_TIME;
1651 bool dirty = false;
1652
1653 if (flags & S_ATIME)
1654 inode->i_atime = *time;
1655 if (flags & S_VERSION)
1656 dirty = inode_maybe_inc_iversion(inode, false);
1657 if (flags & S_CTIME)
1658 inode->i_ctime = *time;
1659 if (flags & S_MTIME)
1660 inode->i_mtime = *time;
1661 if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
1662 !(inode->i_sb->s_flags & SB_LAZYTIME))
1663 dirty = true;
1664
1665 if (dirty)
1666 iflags |= I_DIRTY_SYNC;
1667 __mark_inode_dirty(inode, iflags);
1668 return 0;
1669}
1670EXPORT_SYMBOL(generic_update_time);
1671
1672/*
1673 * This does the actual work of updating an inodes time or version. Must have
1674 * had called mnt_want_write() before calling this.
1675 */
1676static int update_time(struct inode *inode, struct timespec64 *time, int flags)
1677{
1678 int (*update_time)(struct inode *, struct timespec64 *, int);
1679
1680 update_time = inode->i_op->update_time ? inode->i_op->update_time :
1681 generic_update_time;
1682
1683 return update_time(inode, time, flags);
1684}
1685
1686/**
1687 * touch_atime - update the access time
1688 * @path: the &struct path to update
1689 * @inode: inode to update
1690 *
1691 * Update the accessed time on an inode and mark it for writeback.
1692 * This function automatically handles read only file systems and media,
1693 * as well as the "noatime" flag and inode specific "noatime" markers.
1694 */
1695bool atime_needs_update(const struct path *path, struct inode *inode)
1696{
1697 struct vfsmount *mnt = path->mnt;
1698 struct timespec64 now;
1699
1700 if (inode->i_flags & S_NOATIME)
1701 return false;
1702
1703 /* Atime updates will likely cause i_uid and i_gid to be written
1704 * back improprely if their true value is unknown to the vfs.
1705 */
1706 if (HAS_UNMAPPED_ID(inode))
1707 return false;
1708
1709 if (IS_NOATIME(inode))
1710 return false;
1711 if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode))
1712 return false;
1713
1714 if (mnt->mnt_flags & MNT_NOATIME)
1715 return false;
1716 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1717 return false;
1718
1719 now = current_time(inode);
1720
1721 if (!relatime_need_update(mnt, inode, now))
1722 return false;
1723
1724 if (timespec64_equal(&inode->i_atime, &now))
1725 return false;
1726
1727 return true;
1728}
1729
1730void touch_atime(const struct path *path)
1731{
1732 struct vfsmount *mnt = path->mnt;
1733 struct inode *inode = d_inode(path->dentry);
1734 struct timespec64 now;
1735
1736 if (!atime_needs_update(path, inode))
1737 return;
1738
1739 if (!sb_start_write_trylock(inode->i_sb))
1740 return;
1741
1742 if (__mnt_want_write(mnt) != 0)
1743 goto skip_update;
1744 /*
1745 * File systems can error out when updating inodes if they need to
1746 * allocate new space to modify an inode (such is the case for
1747 * Btrfs), but since we touch atime while walking down the path we
1748 * really don't care if we failed to update the atime of the file,
1749 * so just ignore the return value.
1750 * We may also fail on filesystems that have the ability to make parts
1751 * of the fs read only, e.g. subvolumes in Btrfs.
1752 */
1753 now = current_time(inode);
1754 update_time(inode, &now, S_ATIME);
1755 __mnt_drop_write(mnt);
1756skip_update:
1757 sb_end_write(inode->i_sb);
1758}
1759EXPORT_SYMBOL(touch_atime);
1760
1761/*
1762 * The logic we want is
1763 *
1764 * if suid or (sgid and xgrp)
1765 * remove privs
1766 */
1767int should_remove_suid(struct dentry *dentry)
1768{
1769 umode_t mode = d_inode(dentry)->i_mode;
1770 int kill = 0;
1771
1772 /* suid always must be killed */
1773 if (unlikely(mode & S_ISUID))
1774 kill = ATTR_KILL_SUID;
1775
1776 /*
1777 * sgid without any exec bits is just a mandatory locking mark; leave
1778 * it alone. If some exec bits are set, it's a real sgid; kill it.
1779 */
1780 if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1781 kill |= ATTR_KILL_SGID;
1782
1783 if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
1784 return kill;
1785
1786 return 0;
1787}
1788EXPORT_SYMBOL(should_remove_suid);
1789
1790/*
1791 * Return mask of changes for notify_change() that need to be done as a
1792 * response to write or truncate. Return 0 if nothing has to be changed.
1793 * Negative value on error (change should be denied).
1794 */
1795int dentry_needs_remove_privs(struct dentry *dentry)
1796{
1797 struct inode *inode = d_inode(dentry);
1798 int mask = 0;
1799 int ret;
1800
1801 if (IS_NOSEC(inode))
1802 return 0;
1803
1804 mask = should_remove_suid(dentry);
1805 ret = security_inode_need_killpriv(dentry);
1806 if (ret < 0)
1807 return ret;
1808 if (ret)
1809 mask |= ATTR_KILL_PRIV;
1810 return mask;
1811}
1812
1813static int __remove_privs(struct dentry *dentry, int kill)
1814{
1815 struct iattr newattrs;
1816
1817 newattrs.ia_valid = ATTR_FORCE | kill;
1818 /*
1819 * Note we call this on write, so notify_change will not
1820 * encounter any conflicting delegations:
1821 */
1822 return notify_change(dentry, &newattrs, NULL);
1823}
1824
1825/*
1826 * Remove special file priviledges (suid, capabilities) when file is written
1827 * to or truncated.
1828 */
1829int file_remove_privs(struct file *file)
1830{
1831 struct dentry *dentry = file_dentry(file);
1832 struct inode *inode = file_inode(file);
1833 int kill;
1834 int error = 0;
1835
1836 /*
1837 * Fast path for nothing security related.
1838 * As well for non-regular files, e.g. blkdev inodes.
1839 * For example, blkdev_write_iter() might get here
1840 * trying to remove privs which it is not allowed to.
1841 */
1842 if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
1843 return 0;
1844
1845 kill = dentry_needs_remove_privs(dentry);
1846 if (kill < 0)
1847 return kill;
1848 if (kill)
1849 error = __remove_privs(dentry, kill);
1850 if (!error)
1851 inode_has_no_xattr(inode);
1852
1853 return error;
1854}
1855EXPORT_SYMBOL(file_remove_privs);
1856
1857/**
1858 * file_update_time - update mtime and ctime time
1859 * @file: file accessed
1860 *
1861 * Update the mtime and ctime members of an inode and mark the inode
1862 * for writeback. Note that this function is meant exclusively for
1863 * usage in the file write path of filesystems, and filesystems may
1864 * choose to explicitly ignore update via this function with the
1865 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1866 * timestamps are handled by the server. This can return an error for
1867 * file systems who need to allocate space in order to update an inode.
1868 */
1869
1870int file_update_time(struct file *file)
1871{
1872 struct inode *inode = file_inode(file);
1873 struct timespec64 now;
1874 int sync_it = 0;
1875 int ret;
1876
1877 /* First try to exhaust all avenues to not sync */
1878 if (IS_NOCMTIME(inode))
1879 return 0;
1880
1881 now = current_time(inode);
1882 if (!timespec64_equal(&inode->i_mtime, &now))
1883 sync_it = S_MTIME;
1884
1885 if (!timespec64_equal(&inode->i_ctime, &now))
1886 sync_it |= S_CTIME;
1887
1888 if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
1889 sync_it |= S_VERSION;
1890
1891 if (!sync_it)
1892 return 0;
1893
1894 /* Finally allowed to write? Takes lock. */
1895 if (__mnt_want_write_file(file))
1896 return 0;
1897
1898 ret = update_time(inode, &now, sync_it);
1899 __mnt_drop_write_file(file);
1900
1901 return ret;
1902}
1903EXPORT_SYMBOL(file_update_time);
1904
1905/* Caller must hold the file's inode lock */
1906int file_modified(struct file *file)
1907{
1908 int err;
1909
1910 /*
1911 * Clear the security bits if the process is not being run by root.
1912 * This keeps people from modifying setuid and setgid binaries.
1913 */
1914 err = file_remove_privs(file);
1915 if (err)
1916 return err;
1917
1918 if (unlikely(file->f_mode & FMODE_NOCMTIME))
1919 return 0;
1920
1921 return file_update_time(file);
1922}
1923EXPORT_SYMBOL(file_modified);
1924
1925int inode_needs_sync(struct inode *inode)
1926{
1927 if (IS_SYNC(inode))
1928 return 1;
1929 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1930 return 1;
1931 return 0;
1932}
1933EXPORT_SYMBOL(inode_needs_sync);
1934
1935/*
1936 * If we try to find an inode in the inode hash while it is being
1937 * deleted, we have to wait until the filesystem completes its
1938 * deletion before reporting that it isn't found. This function waits
1939 * until the deletion _might_ have completed. Callers are responsible
1940 * to recheck inode state.
1941 *
1942 * It doesn't matter if I_NEW is not set initially, a call to
1943 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1944 * will DTRT.
1945 */
1946static void __wait_on_freeing_inode(struct inode *inode)
1947{
1948 wait_queue_head_t *wq;
1949 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1950 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1951 prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
1952 spin_unlock(&inode->i_lock);
1953 spin_unlock(&inode_hash_lock);
1954 schedule();
1955 finish_wait(wq, &wait.wq_entry);
1956 spin_lock(&inode_hash_lock);
1957}
1958
1959static __initdata unsigned long ihash_entries;
1960static int __init set_ihash_entries(char *str)
1961{
1962 if (!str)
1963 return 0;
1964 ihash_entries = simple_strtoul(str, &str, 0);
1965 return 1;
1966}
1967__setup("ihash_entries=", set_ihash_entries);
1968
1969/*
1970 * Initialize the waitqueues and inode hash table.
1971 */
1972void __init inode_init_early(void)
1973{
1974 /* If hashes are distributed across NUMA nodes, defer
1975 * hash allocation until vmalloc space is available.
1976 */
1977 if (hashdist)
1978 return;
1979
1980 inode_hashtable =
1981 alloc_large_system_hash("Inode-cache",
1982 sizeof(struct hlist_head),
1983 ihash_entries,
1984 14,
1985 HASH_EARLY | HASH_ZERO,
1986 &i_hash_shift,
1987 &i_hash_mask,
1988 0,
1989 0);
1990}
1991
1992void __init inode_init(void)
1993{
1994 /* inode slab cache */
1995 inode_cachep = kmem_cache_create("inode_cache",
1996 sizeof(struct inode),
1997 0,
1998 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1999 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
2000 init_once);
2001
2002 /* Hash may have been set up in inode_init_early */
2003 if (!hashdist)
2004 return;
2005
2006 inode_hashtable =
2007 alloc_large_system_hash("Inode-cache",
2008 sizeof(struct hlist_head),
2009 ihash_entries,
2010 14,
2011 HASH_ZERO,
2012 &i_hash_shift,
2013 &i_hash_mask,
2014 0,
2015 0);
2016}
2017
2018void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
2019{
2020 inode->i_mode = mode;
2021 if (S_ISCHR(mode)) {
2022 inode->i_fop = &def_chr_fops;
2023 inode->i_rdev = rdev;
2024 } else if (S_ISBLK(mode)) {
2025 inode->i_fop = &def_blk_fops;
2026 inode->i_rdev = rdev;
2027 } else if (S_ISFIFO(mode))
2028 inode->i_fop = &pipefifo_fops;
2029 else if (S_ISSOCK(mode))
2030 ; /* leave it no_open_fops */
2031 else
2032 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
2033 " inode %s:%lu\n", mode, inode->i_sb->s_id,
2034 inode->i_ino);
2035}
2036EXPORT_SYMBOL(init_special_inode);
2037
2038/**
2039 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
2040 * @inode: New inode
2041 * @dir: Directory inode
2042 * @mode: mode of the new inode
2043 */
2044void inode_init_owner(struct inode *inode, const struct inode *dir,
2045 umode_t mode)
2046{
2047 inode->i_uid = current_fsuid();
2048 if (dir && dir->i_mode & S_ISGID) {
2049 inode->i_gid = dir->i_gid;
2050
2051 /* Directories are special, and always inherit S_ISGID */
2052 if (S_ISDIR(mode))
2053 mode |= S_ISGID;
2054 else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) &&
2055 !in_group_p(inode->i_gid) &&
2056 !capable_wrt_inode_uidgid(dir, CAP_FSETID))
2057 mode &= ~S_ISGID;
2058 } else
2059 inode->i_gid = current_fsgid();
2060 inode->i_mode = mode;
2061}
2062EXPORT_SYMBOL(inode_init_owner);
2063
2064/**
2065 * inode_owner_or_capable - check current task permissions to inode
2066 * @inode: inode being checked
2067 *
2068 * Return true if current either has CAP_FOWNER in a namespace with the
2069 * inode owner uid mapped, or owns the file.
2070 */
2071bool inode_owner_or_capable(const struct inode *inode)
2072{
2073 struct user_namespace *ns;
2074
2075 if (uid_eq(current_fsuid(), inode->i_uid))
2076 return true;
2077
2078 ns = current_user_ns();
2079 if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
2080 return true;
2081 return false;
2082}
2083EXPORT_SYMBOL(inode_owner_or_capable);
2084
2085/*
2086 * Direct i/o helper functions
2087 */
2088static void __inode_dio_wait(struct inode *inode)
2089{
2090 wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
2091 DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
2092
2093 do {
2094 prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE);
2095 if (atomic_read(&inode->i_dio_count))
2096 schedule();
2097 } while (atomic_read(&inode->i_dio_count));
2098 finish_wait(wq, &q.wq_entry);
2099}
2100
2101/**
2102 * inode_dio_wait - wait for outstanding DIO requests to finish
2103 * @inode: inode to wait for
2104 *
2105 * Waits for all pending direct I/O requests to finish so that we can
2106 * proceed with a truncate or equivalent operation.
2107 *
2108 * Must be called under a lock that serializes taking new references
2109 * to i_dio_count, usually by inode->i_mutex.
2110 */
2111void inode_dio_wait(struct inode *inode)
2112{
2113 if (atomic_read(&inode->i_dio_count))
2114 __inode_dio_wait(inode);
2115}
2116EXPORT_SYMBOL(inode_dio_wait);
2117
2118/*
2119 * inode_set_flags - atomically set some inode flags
2120 *
2121 * Note: the caller should be holding i_mutex, or else be sure that
2122 * they have exclusive access to the inode structure (i.e., while the
2123 * inode is being instantiated). The reason for the cmpxchg() loop
2124 * --- which wouldn't be necessary if all code paths which modify
2125 * i_flags actually followed this rule, is that there is at least one
2126 * code path which doesn't today so we use cmpxchg() out of an abundance
2127 * of caution.
2128 *
2129 * In the long run, i_mutex is overkill, and we should probably look
2130 * at using the i_lock spinlock to protect i_flags, and then make sure
2131 * it is so documented in include/linux/fs.h and that all code follows
2132 * the locking convention!!
2133 */
2134void inode_set_flags(struct inode *inode, unsigned int flags,
2135 unsigned int mask)
2136{
2137 WARN_ON_ONCE(flags & ~mask);
2138 set_mask_bits(&inode->i_flags, mask, flags);
2139}
2140EXPORT_SYMBOL(inode_set_flags);
2141
2142void inode_nohighmem(struct inode *inode)
2143{
2144 mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
2145}
2146EXPORT_SYMBOL(inode_nohighmem);
2147
2148/**
2149 * timespec64_trunc - Truncate timespec64 to a granularity
2150 * @t: Timespec64
2151 * @gran: Granularity in ns.
2152 *
2153 * Truncate a timespec64 to a granularity. Always rounds down. gran must
2154 * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
2155 */
2156struct timespec64 timespec64_trunc(struct timespec64 t, unsigned gran)
2157{
2158 /* Avoid division in the common cases 1 ns and 1 s. */
2159 if (gran == 1) {
2160 /* nothing */
2161 } else if (gran == NSEC_PER_SEC) {
2162 t.tv_nsec = 0;
2163 } else if (gran > 1 && gran < NSEC_PER_SEC) {
2164 t.tv_nsec -= t.tv_nsec % gran;
2165 } else {
2166 WARN(1, "illegal file time granularity: %u", gran);
2167 }
2168 return t;
2169}
2170EXPORT_SYMBOL(timespec64_trunc);
2171
2172/**
2173 * timestamp_truncate - Truncate timespec to a granularity
2174 * @t: Timespec
2175 * @inode: inode being updated
2176 *
2177 * Truncate a timespec to the granularity supported by the fs
2178 * containing the inode. Always rounds down. gran must
2179 * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
2180 */
2181struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode)
2182{
2183 struct super_block *sb = inode->i_sb;
2184 unsigned int gran = sb->s_time_gran;
2185
2186 t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max);
2187 if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min))
2188 t.tv_nsec = 0;
2189
2190 /* Avoid division in the common cases 1 ns and 1 s. */
2191 if (gran == 1)
2192 ; /* nothing */
2193 else if (gran == NSEC_PER_SEC)
2194 t.tv_nsec = 0;
2195 else if (gran > 1 && gran < NSEC_PER_SEC)
2196 t.tv_nsec -= t.tv_nsec % gran;
2197 else
2198 WARN(1, "invalid file time granularity: %u", gran);
2199 return t;
2200}
2201EXPORT_SYMBOL(timestamp_truncate);
2202
2203/**
2204 * current_time - Return FS time
2205 * @inode: inode.
2206 *
2207 * Return the current time truncated to the time granularity supported by
2208 * the fs.
2209 *
2210 * Note that inode and inode->sb cannot be NULL.
2211 * Otherwise, the function warns and returns time without truncation.
2212 */
2213struct timespec64 current_time(struct inode *inode)
2214{
2215 struct timespec64 now;
2216
2217 ktime_get_coarse_real_ts64(&now);
2218
2219 if (unlikely(!inode->i_sb)) {
2220 WARN(1, "current_time() called with uninitialized super_block in the inode");
2221 return now;
2222 }
2223
2224 return timestamp_truncate(now, inode);
2225}
2226EXPORT_SYMBOL(current_time);
2227
2228/*
2229 * Generic function to check FS_IOC_SETFLAGS values and reject any invalid
2230 * configurations.
2231 *
2232 * Note: the caller should be holding i_mutex, or else be sure that they have
2233 * exclusive access to the inode structure.
2234 */
2235int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
2236 unsigned int flags)
2237{
2238 /*
2239 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
2240 * the relevant capability.
2241 *
2242 * This test looks nicer. Thanks to Pauline Middelink
2243 */
2244 if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
2245 !capable(CAP_LINUX_IMMUTABLE))
2246 return -EPERM;
2247
2248 return 0;
2249}
2250EXPORT_SYMBOL(vfs_ioc_setflags_prepare);
2251
2252/*
2253 * Generic function to check FS_IOC_FSSETXATTR values and reject any invalid
2254 * configurations.
2255 *
2256 * Note: the caller should be holding i_mutex, or else be sure that they have
2257 * exclusive access to the inode structure.
2258 */
2259int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
2260 struct fsxattr *fa)
2261{
2262 /*
2263 * Can't modify an immutable/append-only file unless we have
2264 * appropriate permission.
2265 */
2266 if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
2267 (FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND) &&
2268 !capable(CAP_LINUX_IMMUTABLE))
2269 return -EPERM;
2270
2271 /*
2272 * Project Quota ID state is only allowed to change from within the init
2273 * namespace. Enforce that restriction only if we are trying to change
2274 * the quota ID state. Everything else is allowed in user namespaces.
2275 */
2276 if (current_user_ns() != &init_user_ns) {
2277 if (old_fa->fsx_projid != fa->fsx_projid)
2278 return -EINVAL;
2279 if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
2280 FS_XFLAG_PROJINHERIT)
2281 return -EINVAL;
2282 }
2283
2284 /* Check extent size hints. */
2285 if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
2286 return -EINVAL;
2287
2288 if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
2289 !S_ISDIR(inode->i_mode))
2290 return -EINVAL;
2291
2292 if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
2293 !S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
2294 return -EINVAL;
2295
2296 /*
2297 * It is only valid to set the DAX flag on regular files and
2298 * directories on filesystems.
2299 */
2300 if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
2301 !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
2302 return -EINVAL;
2303
2304 /* Extent size hints of zero turn off the flags. */
2305 if (fa->fsx_extsize == 0)
2306 fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
2307 if (fa->fsx_cowextsize == 0)
2308 fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
2309
2310 return 0;
2311}
2312EXPORT_SYMBOL(vfs_ioc_fssetxattr_check);