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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/filelock.h>
9#include <linux/mm.h>
10#include <linux/backing-dev.h>
11#include <linux/hash.h>
12#include <linux/swap.h>
13#include <linux/security.h>
14#include <linux/cdev.h>
15#include <linux/memblock.h>
16#include <linux/fsnotify.h>
17#include <linux/mount.h>
18#include <linux/posix_acl.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 <linux/rw_hint.h>
24#include <trace/events/writeback.h>
25#include "internal.h"
26
27/*
28 * Inode locking rules:
29 *
30 * inode->i_lock protects:
31 * inode->i_state, inode->i_hash, __iget(), inode->i_io_list
32 * Inode LRU list locks protect:
33 * inode->i_sb->s_inode_lru, inode->i_lru
34 * inode->i_sb->s_inode_list_lock protects:
35 * inode->i_sb->s_inodes, inode->i_sb_list
36 * bdi->wb.list_lock protects:
37 * bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list
38 * inode_hash_lock protects:
39 * inode_hashtable, inode->i_hash
40 *
41 * Lock ordering:
42 *
43 * inode->i_sb->s_inode_list_lock
44 * inode->i_lock
45 * Inode LRU list locks
46 *
47 * bdi->wb.list_lock
48 * inode->i_lock
49 *
50 * inode_hash_lock
51 * inode->i_sb->s_inode_list_lock
52 * inode->i_lock
53 *
54 * iunique_lock
55 * inode_hash_lock
56 */
57
58static unsigned int i_hash_mask __ro_after_init;
59static unsigned int i_hash_shift __ro_after_init;
60static struct hlist_head *inode_hashtable __ro_after_init;
61static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
62
63/*
64 * Empty aops. Can be used for the cases where the user does not
65 * define any of the address_space operations.
66 */
67const struct address_space_operations empty_aops = {
68};
69EXPORT_SYMBOL(empty_aops);
70
71static DEFINE_PER_CPU(unsigned long, nr_inodes);
72static DEFINE_PER_CPU(unsigned long, nr_unused);
73
74static struct kmem_cache *inode_cachep __ro_after_init;
75
76static long get_nr_inodes(void)
77{
78 int i;
79 long sum = 0;
80 for_each_possible_cpu(i)
81 sum += per_cpu(nr_inodes, i);
82 return sum < 0 ? 0 : sum;
83}
84
85static inline long get_nr_inodes_unused(void)
86{
87 int i;
88 long sum = 0;
89 for_each_possible_cpu(i)
90 sum += per_cpu(nr_unused, i);
91 return sum < 0 ? 0 : sum;
92}
93
94long get_nr_dirty_inodes(void)
95{
96 /* not actually dirty inodes, but a wild approximation */
97 long nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
98 return nr_dirty > 0 ? nr_dirty : 0;
99}
100
101/*
102 * Handle nr_inode sysctl
103 */
104#ifdef CONFIG_SYSCTL
105/*
106 * Statistics gathering..
107 */
108static struct inodes_stat_t inodes_stat;
109
110static int proc_nr_inodes(struct ctl_table *table, int write, void *buffer,
111 size_t *lenp, loff_t *ppos)
112{
113 inodes_stat.nr_inodes = get_nr_inodes();
114 inodes_stat.nr_unused = get_nr_inodes_unused();
115 return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
116}
117
118static struct ctl_table inodes_sysctls[] = {
119 {
120 .procname = "inode-nr",
121 .data = &inodes_stat,
122 .maxlen = 2*sizeof(long),
123 .mode = 0444,
124 .proc_handler = proc_nr_inodes,
125 },
126 {
127 .procname = "inode-state",
128 .data = &inodes_stat,
129 .maxlen = 7*sizeof(long),
130 .mode = 0444,
131 .proc_handler = proc_nr_inodes,
132 },
133};
134
135static int __init init_fs_inode_sysctls(void)
136{
137 register_sysctl_init("fs", inodes_sysctls);
138 return 0;
139}
140early_initcall(init_fs_inode_sysctls);
141#endif
142
143static int no_open(struct inode *inode, struct file *file)
144{
145 return -ENXIO;
146}
147
148/**
149 * inode_init_always - perform inode structure initialisation
150 * @sb: superblock inode belongs to
151 * @inode: inode to initialise
152 *
153 * These are initializations that need to be done on every inode
154 * allocation as the fields are not initialised by slab allocation.
155 */
156int inode_init_always(struct super_block *sb, struct inode *inode)
157{
158 static const struct inode_operations empty_iops;
159 static const struct file_operations no_open_fops = {.open = no_open};
160 struct address_space *const mapping = &inode->i_data;
161
162 inode->i_sb = sb;
163 inode->i_blkbits = sb->s_blocksize_bits;
164 inode->i_flags = 0;
165 atomic64_set(&inode->i_sequence, 0);
166 atomic_set(&inode->i_count, 1);
167 inode->i_op = &empty_iops;
168 inode->i_fop = &no_open_fops;
169 inode->i_ino = 0;
170 inode->__i_nlink = 1;
171 inode->i_opflags = 0;
172 if (sb->s_xattr)
173 inode->i_opflags |= IOP_XATTR;
174 i_uid_write(inode, 0);
175 i_gid_write(inode, 0);
176 atomic_set(&inode->i_writecount, 0);
177 inode->i_size = 0;
178 inode->i_write_hint = WRITE_LIFE_NOT_SET;
179 inode->i_blocks = 0;
180 inode->i_bytes = 0;
181 inode->i_generation = 0;
182 inode->i_pipe = NULL;
183 inode->i_cdev = NULL;
184 inode->i_link = NULL;
185 inode->i_dir_seq = 0;
186 inode->i_rdev = 0;
187 inode->dirtied_when = 0;
188
189#ifdef CONFIG_CGROUP_WRITEBACK
190 inode->i_wb_frn_winner = 0;
191 inode->i_wb_frn_avg_time = 0;
192 inode->i_wb_frn_history = 0;
193#endif
194
195 spin_lock_init(&inode->i_lock);
196 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
197
198 init_rwsem(&inode->i_rwsem);
199 lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key);
200
201 atomic_set(&inode->i_dio_count, 0);
202
203 mapping->a_ops = &empty_aops;
204 mapping->host = inode;
205 mapping->flags = 0;
206 mapping->wb_err = 0;
207 atomic_set(&mapping->i_mmap_writable, 0);
208#ifdef CONFIG_READ_ONLY_THP_FOR_FS
209 atomic_set(&mapping->nr_thps, 0);
210#endif
211 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
212 mapping->i_private_data = NULL;
213 mapping->writeback_index = 0;
214 init_rwsem(&mapping->invalidate_lock);
215 lockdep_set_class_and_name(&mapping->invalidate_lock,
216 &sb->s_type->invalidate_lock_key,
217 "mapping.invalidate_lock");
218 if (sb->s_iflags & SB_I_STABLE_WRITES)
219 mapping_set_stable_writes(mapping);
220 inode->i_private = NULL;
221 inode->i_mapping = mapping;
222 INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
223#ifdef CONFIG_FS_POSIX_ACL
224 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
225#endif
226
227#ifdef CONFIG_FSNOTIFY
228 inode->i_fsnotify_mask = 0;
229#endif
230 inode->i_flctx = NULL;
231
232 if (unlikely(security_inode_alloc(inode)))
233 return -ENOMEM;
234 this_cpu_inc(nr_inodes);
235
236 return 0;
237}
238EXPORT_SYMBOL(inode_init_always);
239
240void free_inode_nonrcu(struct inode *inode)
241{
242 kmem_cache_free(inode_cachep, inode);
243}
244EXPORT_SYMBOL(free_inode_nonrcu);
245
246static void i_callback(struct rcu_head *head)
247{
248 struct inode *inode = container_of(head, struct inode, i_rcu);
249 if (inode->free_inode)
250 inode->free_inode(inode);
251 else
252 free_inode_nonrcu(inode);
253}
254
255static struct inode *alloc_inode(struct super_block *sb)
256{
257 const struct super_operations *ops = sb->s_op;
258 struct inode *inode;
259
260 if (ops->alloc_inode)
261 inode = ops->alloc_inode(sb);
262 else
263 inode = alloc_inode_sb(sb, inode_cachep, GFP_KERNEL);
264
265 if (!inode)
266 return NULL;
267
268 if (unlikely(inode_init_always(sb, inode))) {
269 if (ops->destroy_inode) {
270 ops->destroy_inode(inode);
271 if (!ops->free_inode)
272 return NULL;
273 }
274 inode->free_inode = ops->free_inode;
275 i_callback(&inode->i_rcu);
276 return NULL;
277 }
278
279 return inode;
280}
281
282void __destroy_inode(struct inode *inode)
283{
284 BUG_ON(inode_has_buffers(inode));
285 inode_detach_wb(inode);
286 security_inode_free(inode);
287 fsnotify_inode_delete(inode);
288 locks_free_lock_context(inode);
289 if (!inode->i_nlink) {
290 WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
291 atomic_long_dec(&inode->i_sb->s_remove_count);
292 }
293
294#ifdef CONFIG_FS_POSIX_ACL
295 if (inode->i_acl && !is_uncached_acl(inode->i_acl))
296 posix_acl_release(inode->i_acl);
297 if (inode->i_default_acl && !is_uncached_acl(inode->i_default_acl))
298 posix_acl_release(inode->i_default_acl);
299#endif
300 this_cpu_dec(nr_inodes);
301}
302EXPORT_SYMBOL(__destroy_inode);
303
304static void destroy_inode(struct inode *inode)
305{
306 const struct super_operations *ops = inode->i_sb->s_op;
307
308 BUG_ON(!list_empty(&inode->i_lru));
309 __destroy_inode(inode);
310 if (ops->destroy_inode) {
311 ops->destroy_inode(inode);
312 if (!ops->free_inode)
313 return;
314 }
315 inode->free_inode = ops->free_inode;
316 call_rcu(&inode->i_rcu, i_callback);
317}
318
319/**
320 * drop_nlink - directly drop an inode's link count
321 * @inode: inode
322 *
323 * This is a low-level filesystem helper to replace any
324 * direct filesystem manipulation of i_nlink. In cases
325 * where we are attempting to track writes to the
326 * filesystem, a decrement to zero means an imminent
327 * write when the file is truncated and actually unlinked
328 * on the filesystem.
329 */
330void drop_nlink(struct inode *inode)
331{
332 WARN_ON(inode->i_nlink == 0);
333 inode->__i_nlink--;
334 if (!inode->i_nlink)
335 atomic_long_inc(&inode->i_sb->s_remove_count);
336}
337EXPORT_SYMBOL(drop_nlink);
338
339/**
340 * clear_nlink - directly zero an inode's link count
341 * @inode: inode
342 *
343 * This is a low-level filesystem helper to replace any
344 * direct filesystem manipulation of i_nlink. See
345 * drop_nlink() for why we care about i_nlink hitting zero.
346 */
347void clear_nlink(struct inode *inode)
348{
349 if (inode->i_nlink) {
350 inode->__i_nlink = 0;
351 atomic_long_inc(&inode->i_sb->s_remove_count);
352 }
353}
354EXPORT_SYMBOL(clear_nlink);
355
356/**
357 * set_nlink - directly set an inode's link count
358 * @inode: inode
359 * @nlink: new nlink (should be non-zero)
360 *
361 * This is a low-level filesystem helper to replace any
362 * direct filesystem manipulation of i_nlink.
363 */
364void set_nlink(struct inode *inode, unsigned int nlink)
365{
366 if (!nlink) {
367 clear_nlink(inode);
368 } else {
369 /* Yes, some filesystems do change nlink from zero to one */
370 if (inode->i_nlink == 0)
371 atomic_long_dec(&inode->i_sb->s_remove_count);
372
373 inode->__i_nlink = nlink;
374 }
375}
376EXPORT_SYMBOL(set_nlink);
377
378/**
379 * inc_nlink - directly increment an inode's link count
380 * @inode: inode
381 *
382 * This is a low-level filesystem helper to replace any
383 * direct filesystem manipulation of i_nlink. Currently,
384 * it is only here for parity with dec_nlink().
385 */
386void inc_nlink(struct inode *inode)
387{
388 if (unlikely(inode->i_nlink == 0)) {
389 WARN_ON(!(inode->i_state & I_LINKABLE));
390 atomic_long_dec(&inode->i_sb->s_remove_count);
391 }
392
393 inode->__i_nlink++;
394}
395EXPORT_SYMBOL(inc_nlink);
396
397static void __address_space_init_once(struct address_space *mapping)
398{
399 xa_init_flags(&mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT);
400 init_rwsem(&mapping->i_mmap_rwsem);
401 INIT_LIST_HEAD(&mapping->i_private_list);
402 spin_lock_init(&mapping->i_private_lock);
403 mapping->i_mmap = RB_ROOT_CACHED;
404}
405
406void address_space_init_once(struct address_space *mapping)
407{
408 memset(mapping, 0, sizeof(*mapping));
409 __address_space_init_once(mapping);
410}
411EXPORT_SYMBOL(address_space_init_once);
412
413/*
414 * These are initializations that only need to be done
415 * once, because the fields are idempotent across use
416 * of the inode, so let the slab aware of that.
417 */
418void inode_init_once(struct inode *inode)
419{
420 memset(inode, 0, sizeof(*inode));
421 INIT_HLIST_NODE(&inode->i_hash);
422 INIT_LIST_HEAD(&inode->i_devices);
423 INIT_LIST_HEAD(&inode->i_io_list);
424 INIT_LIST_HEAD(&inode->i_wb_list);
425 INIT_LIST_HEAD(&inode->i_lru);
426 INIT_LIST_HEAD(&inode->i_sb_list);
427 __address_space_init_once(&inode->i_data);
428 i_size_ordered_init(inode);
429}
430EXPORT_SYMBOL(inode_init_once);
431
432static void init_once(void *foo)
433{
434 struct inode *inode = (struct inode *) foo;
435
436 inode_init_once(inode);
437}
438
439/*
440 * inode->i_lock must be held
441 */
442void __iget(struct inode *inode)
443{
444 atomic_inc(&inode->i_count);
445}
446
447/*
448 * get additional reference to inode; caller must already hold one.
449 */
450void ihold(struct inode *inode)
451{
452 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
453}
454EXPORT_SYMBOL(ihold);
455
456static void __inode_add_lru(struct inode *inode, bool rotate)
457{
458 if (inode->i_state & (I_DIRTY_ALL | I_SYNC | I_FREEING | I_WILL_FREE))
459 return;
460 if (atomic_read(&inode->i_count))
461 return;
462 if (!(inode->i_sb->s_flags & SB_ACTIVE))
463 return;
464 if (!mapping_shrinkable(&inode->i_data))
465 return;
466
467 if (list_lru_add_obj(&inode->i_sb->s_inode_lru, &inode->i_lru))
468 this_cpu_inc(nr_unused);
469 else if (rotate)
470 inode->i_state |= I_REFERENCED;
471}
472
473/*
474 * Add inode to LRU if needed (inode is unused and clean).
475 *
476 * Needs inode->i_lock held.
477 */
478void inode_add_lru(struct inode *inode)
479{
480 __inode_add_lru(inode, false);
481}
482
483static void inode_lru_list_del(struct inode *inode)
484{
485 if (list_lru_del_obj(&inode->i_sb->s_inode_lru, &inode->i_lru))
486 this_cpu_dec(nr_unused);
487}
488
489/**
490 * inode_sb_list_add - add inode to the superblock list of inodes
491 * @inode: inode to add
492 */
493void inode_sb_list_add(struct inode *inode)
494{
495 spin_lock(&inode->i_sb->s_inode_list_lock);
496 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
497 spin_unlock(&inode->i_sb->s_inode_list_lock);
498}
499EXPORT_SYMBOL_GPL(inode_sb_list_add);
500
501static inline void inode_sb_list_del(struct inode *inode)
502{
503 if (!list_empty(&inode->i_sb_list)) {
504 spin_lock(&inode->i_sb->s_inode_list_lock);
505 list_del_init(&inode->i_sb_list);
506 spin_unlock(&inode->i_sb->s_inode_list_lock);
507 }
508}
509
510static unsigned long hash(struct super_block *sb, unsigned long hashval)
511{
512 unsigned long tmp;
513
514 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
515 L1_CACHE_BYTES;
516 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
517 return tmp & i_hash_mask;
518}
519
520/**
521 * __insert_inode_hash - hash an inode
522 * @inode: unhashed inode
523 * @hashval: unsigned long value used to locate this object in the
524 * inode_hashtable.
525 *
526 * Add an inode to the inode hash for this superblock.
527 */
528void __insert_inode_hash(struct inode *inode, unsigned long hashval)
529{
530 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
531
532 spin_lock(&inode_hash_lock);
533 spin_lock(&inode->i_lock);
534 hlist_add_head_rcu(&inode->i_hash, b);
535 spin_unlock(&inode->i_lock);
536 spin_unlock(&inode_hash_lock);
537}
538EXPORT_SYMBOL(__insert_inode_hash);
539
540/**
541 * __remove_inode_hash - remove an inode from the hash
542 * @inode: inode to unhash
543 *
544 * Remove an inode from the superblock.
545 */
546void __remove_inode_hash(struct inode *inode)
547{
548 spin_lock(&inode_hash_lock);
549 spin_lock(&inode->i_lock);
550 hlist_del_init_rcu(&inode->i_hash);
551 spin_unlock(&inode->i_lock);
552 spin_unlock(&inode_hash_lock);
553}
554EXPORT_SYMBOL(__remove_inode_hash);
555
556void dump_mapping(const struct address_space *mapping)
557{
558 struct inode *host;
559 const struct address_space_operations *a_ops;
560 struct hlist_node *dentry_first;
561 struct dentry *dentry_ptr;
562 struct dentry dentry;
563 unsigned long ino;
564
565 /*
566 * If mapping is an invalid pointer, we don't want to crash
567 * accessing it, so probe everything depending on it carefully.
568 */
569 if (get_kernel_nofault(host, &mapping->host) ||
570 get_kernel_nofault(a_ops, &mapping->a_ops)) {
571 pr_warn("invalid mapping:%px\n", mapping);
572 return;
573 }
574
575 if (!host) {
576 pr_warn("aops:%ps\n", a_ops);
577 return;
578 }
579
580 if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
581 get_kernel_nofault(ino, &host->i_ino)) {
582 pr_warn("aops:%ps invalid inode:%px\n", a_ops, host);
583 return;
584 }
585
586 if (!dentry_first) {
587 pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
588 return;
589 }
590
591 dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
592 if (get_kernel_nofault(dentry, dentry_ptr) ||
593 !dentry.d_parent || !dentry.d_name.name) {
594 pr_warn("aops:%ps ino:%lx invalid dentry:%px\n",
595 a_ops, ino, dentry_ptr);
596 return;
597 }
598
599 /*
600 * if dentry is corrupted, the %pd handler may still crash,
601 * but it's unlikely that we reach here with a corrupt mapping
602 */
603 pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry);
604}
605
606void clear_inode(struct inode *inode)
607{
608 /*
609 * We have to cycle the i_pages lock here because reclaim can be in the
610 * process of removing the last page (in __filemap_remove_folio())
611 * and we must not free the mapping under it.
612 */
613 xa_lock_irq(&inode->i_data.i_pages);
614 BUG_ON(inode->i_data.nrpages);
615 /*
616 * Almost always, mapping_empty(&inode->i_data) here; but there are
617 * two known and long-standing ways in which nodes may get left behind
618 * (when deep radix-tree node allocation failed partway; or when THP
619 * collapse_file() failed). Until those two known cases are cleaned up,
620 * or a cleanup function is called here, do not BUG_ON(!mapping_empty),
621 * nor even WARN_ON(!mapping_empty).
622 */
623 xa_unlock_irq(&inode->i_data.i_pages);
624 BUG_ON(!list_empty(&inode->i_data.i_private_list));
625 BUG_ON(!(inode->i_state & I_FREEING));
626 BUG_ON(inode->i_state & I_CLEAR);
627 BUG_ON(!list_empty(&inode->i_wb_list));
628 /* don't need i_lock here, no concurrent mods to i_state */
629 inode->i_state = I_FREEING | I_CLEAR;
630}
631EXPORT_SYMBOL(clear_inode);
632
633/*
634 * Free the inode passed in, removing it from the lists it is still connected
635 * to. We remove any pages still attached to the inode and wait for any IO that
636 * is still in progress before finally destroying the inode.
637 *
638 * An inode must already be marked I_FREEING so that we avoid the inode being
639 * moved back onto lists if we race with other code that manipulates the lists
640 * (e.g. writeback_single_inode). The caller is responsible for setting this.
641 *
642 * An inode must already be removed from the LRU list before being evicted from
643 * the cache. This should occur atomically with setting the I_FREEING state
644 * flag, so no inodes here should ever be on the LRU when being evicted.
645 */
646static void evict(struct inode *inode)
647{
648 const struct super_operations *op = inode->i_sb->s_op;
649
650 BUG_ON(!(inode->i_state & I_FREEING));
651 BUG_ON(!list_empty(&inode->i_lru));
652
653 if (!list_empty(&inode->i_io_list))
654 inode_io_list_del(inode);
655
656 inode_sb_list_del(inode);
657
658 /*
659 * Wait for flusher thread to be done with the inode so that filesystem
660 * does not start destroying it while writeback is still running. Since
661 * the inode has I_FREEING set, flusher thread won't start new work on
662 * the inode. We just have to wait for running writeback to finish.
663 */
664 inode_wait_for_writeback(inode);
665
666 if (op->evict_inode) {
667 op->evict_inode(inode);
668 } else {
669 truncate_inode_pages_final(&inode->i_data);
670 clear_inode(inode);
671 }
672 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
673 cd_forget(inode);
674
675 remove_inode_hash(inode);
676
677 spin_lock(&inode->i_lock);
678 wake_up_bit(&inode->i_state, __I_NEW);
679 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
680 spin_unlock(&inode->i_lock);
681
682 destroy_inode(inode);
683}
684
685/*
686 * dispose_list - dispose of the contents of a local list
687 * @head: the head of the list to free
688 *
689 * Dispose-list gets a local list with local inodes in it, so it doesn't
690 * need to worry about list corruption and SMP locks.
691 */
692static void dispose_list(struct list_head *head)
693{
694 while (!list_empty(head)) {
695 struct inode *inode;
696
697 inode = list_first_entry(head, struct inode, i_lru);
698 list_del_init(&inode->i_lru);
699
700 evict(inode);
701 cond_resched();
702 }
703}
704
705/**
706 * evict_inodes - evict all evictable inodes for a superblock
707 * @sb: superblock to operate on
708 *
709 * Make sure that no inodes with zero refcount are retained. This is
710 * called by superblock shutdown after having SB_ACTIVE flag removed,
711 * so any inode reaching zero refcount during or after that call will
712 * be immediately evicted.
713 */
714void evict_inodes(struct super_block *sb)
715{
716 struct inode *inode, *next;
717 LIST_HEAD(dispose);
718
719again:
720 spin_lock(&sb->s_inode_list_lock);
721 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
722 if (atomic_read(&inode->i_count))
723 continue;
724
725 spin_lock(&inode->i_lock);
726 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
727 spin_unlock(&inode->i_lock);
728 continue;
729 }
730
731 inode->i_state |= I_FREEING;
732 inode_lru_list_del(inode);
733 spin_unlock(&inode->i_lock);
734 list_add(&inode->i_lru, &dispose);
735
736 /*
737 * We can have a ton of inodes to evict at unmount time given
738 * enough memory, check to see if we need to go to sleep for a
739 * bit so we don't livelock.
740 */
741 if (need_resched()) {
742 spin_unlock(&sb->s_inode_list_lock);
743 cond_resched();
744 dispose_list(&dispose);
745 goto again;
746 }
747 }
748 spin_unlock(&sb->s_inode_list_lock);
749
750 dispose_list(&dispose);
751}
752EXPORT_SYMBOL_GPL(evict_inodes);
753
754/**
755 * invalidate_inodes - attempt to free all inodes on a superblock
756 * @sb: superblock to operate on
757 *
758 * Attempts to free all inodes (including dirty inodes) for a given superblock.
759 */
760void invalidate_inodes(struct super_block *sb)
761{
762 struct inode *inode, *next;
763 LIST_HEAD(dispose);
764
765again:
766 spin_lock(&sb->s_inode_list_lock);
767 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
768 spin_lock(&inode->i_lock);
769 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
770 spin_unlock(&inode->i_lock);
771 continue;
772 }
773 if (atomic_read(&inode->i_count)) {
774 spin_unlock(&inode->i_lock);
775 continue;
776 }
777
778 inode->i_state |= I_FREEING;
779 inode_lru_list_del(inode);
780 spin_unlock(&inode->i_lock);
781 list_add(&inode->i_lru, &dispose);
782 if (need_resched()) {
783 spin_unlock(&sb->s_inode_list_lock);
784 cond_resched();
785 dispose_list(&dispose);
786 goto again;
787 }
788 }
789 spin_unlock(&sb->s_inode_list_lock);
790
791 dispose_list(&dispose);
792}
793
794/*
795 * Isolate the inode from the LRU in preparation for freeing it.
796 *
797 * If the inode has the I_REFERENCED flag set, then it means that it has been
798 * used recently - the flag is set in iput_final(). When we encounter such an
799 * inode, clear the flag and move it to the back of the LRU so it gets another
800 * pass through the LRU before it gets reclaimed. This is necessary because of
801 * the fact we are doing lazy LRU updates to minimise lock contention so the
802 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
803 * with this flag set because they are the inodes that are out of order.
804 */
805static enum lru_status inode_lru_isolate(struct list_head *item,
806 struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
807{
808 struct list_head *freeable = arg;
809 struct inode *inode = container_of(item, struct inode, i_lru);
810
811 /*
812 * We are inverting the lru lock/inode->i_lock here, so use a
813 * trylock. If we fail to get the lock, just skip it.
814 */
815 if (!spin_trylock(&inode->i_lock))
816 return LRU_SKIP;
817
818 /*
819 * Inodes can get referenced, redirtied, or repopulated while
820 * they're already on the LRU, and this can make them
821 * unreclaimable for a while. Remove them lazily here; iput,
822 * sync, or the last page cache deletion will requeue them.
823 */
824 if (atomic_read(&inode->i_count) ||
825 (inode->i_state & ~I_REFERENCED) ||
826 !mapping_shrinkable(&inode->i_data)) {
827 list_lru_isolate(lru, &inode->i_lru);
828 spin_unlock(&inode->i_lock);
829 this_cpu_dec(nr_unused);
830 return LRU_REMOVED;
831 }
832
833 /* Recently referenced inodes get one more pass */
834 if (inode->i_state & I_REFERENCED) {
835 inode->i_state &= ~I_REFERENCED;
836 spin_unlock(&inode->i_lock);
837 return LRU_ROTATE;
838 }
839
840 /*
841 * On highmem systems, mapping_shrinkable() permits dropping
842 * page cache in order to free up struct inodes: lowmem might
843 * be under pressure before the cache inside the highmem zone.
844 */
845 if (inode_has_buffers(inode) || !mapping_empty(&inode->i_data)) {
846 __iget(inode);
847 spin_unlock(&inode->i_lock);
848 spin_unlock(lru_lock);
849 if (remove_inode_buffers(inode)) {
850 unsigned long reap;
851 reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
852 if (current_is_kswapd())
853 __count_vm_events(KSWAPD_INODESTEAL, reap);
854 else
855 __count_vm_events(PGINODESTEAL, reap);
856 mm_account_reclaimed_pages(reap);
857 }
858 iput(inode);
859 spin_lock(lru_lock);
860 return LRU_RETRY;
861 }
862
863 WARN_ON(inode->i_state & I_NEW);
864 inode->i_state |= I_FREEING;
865 list_lru_isolate_move(lru, &inode->i_lru, freeable);
866 spin_unlock(&inode->i_lock);
867
868 this_cpu_dec(nr_unused);
869 return LRU_REMOVED;
870}
871
872/*
873 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
874 * This is called from the superblock shrinker function with a number of inodes
875 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
876 * then are freed outside inode_lock by dispose_list().
877 */
878long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
879{
880 LIST_HEAD(freeable);
881 long freed;
882
883 freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
884 inode_lru_isolate, &freeable);
885 dispose_list(&freeable);
886 return freed;
887}
888
889static void __wait_on_freeing_inode(struct inode *inode);
890/*
891 * Called with the inode lock held.
892 */
893static struct inode *find_inode(struct super_block *sb,
894 struct hlist_head *head,
895 int (*test)(struct inode *, void *),
896 void *data)
897{
898 struct inode *inode = NULL;
899
900repeat:
901 hlist_for_each_entry(inode, head, i_hash) {
902 if (inode->i_sb != sb)
903 continue;
904 if (!test(inode, data))
905 continue;
906 spin_lock(&inode->i_lock);
907 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
908 __wait_on_freeing_inode(inode);
909 goto repeat;
910 }
911 if (unlikely(inode->i_state & I_CREATING)) {
912 spin_unlock(&inode->i_lock);
913 return ERR_PTR(-ESTALE);
914 }
915 __iget(inode);
916 spin_unlock(&inode->i_lock);
917 return inode;
918 }
919 return NULL;
920}
921
922/*
923 * find_inode_fast is the fast path version of find_inode, see the comment at
924 * iget_locked for details.
925 */
926static struct inode *find_inode_fast(struct super_block *sb,
927 struct hlist_head *head, unsigned long ino)
928{
929 struct inode *inode = NULL;
930
931repeat:
932 hlist_for_each_entry(inode, head, i_hash) {
933 if (inode->i_ino != ino)
934 continue;
935 if (inode->i_sb != sb)
936 continue;
937 spin_lock(&inode->i_lock);
938 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
939 __wait_on_freeing_inode(inode);
940 goto repeat;
941 }
942 if (unlikely(inode->i_state & I_CREATING)) {
943 spin_unlock(&inode->i_lock);
944 return ERR_PTR(-ESTALE);
945 }
946 __iget(inode);
947 spin_unlock(&inode->i_lock);
948 return inode;
949 }
950 return NULL;
951}
952
953/*
954 * Each cpu owns a range of LAST_INO_BATCH numbers.
955 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
956 * to renew the exhausted range.
957 *
958 * This does not significantly increase overflow rate because every CPU can
959 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
960 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
961 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
962 * overflow rate by 2x, which does not seem too significant.
963 *
964 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
965 * error if st_ino won't fit in target struct field. Use 32bit counter
966 * here to attempt to avoid that.
967 */
968#define LAST_INO_BATCH 1024
969static DEFINE_PER_CPU(unsigned int, last_ino);
970
971unsigned int get_next_ino(void)
972{
973 unsigned int *p = &get_cpu_var(last_ino);
974 unsigned int res = *p;
975
976#ifdef CONFIG_SMP
977 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
978 static atomic_t shared_last_ino;
979 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
980
981 res = next - LAST_INO_BATCH;
982 }
983#endif
984
985 res++;
986 /* get_next_ino should not provide a 0 inode number */
987 if (unlikely(!res))
988 res++;
989 *p = res;
990 put_cpu_var(last_ino);
991 return res;
992}
993EXPORT_SYMBOL(get_next_ino);
994
995/**
996 * new_inode_pseudo - obtain an inode
997 * @sb: superblock
998 *
999 * Allocates a new inode for given superblock.
1000 * Inode wont be chained in superblock s_inodes list
1001 * This means :
1002 * - fs can't be unmount
1003 * - quotas, fsnotify, writeback can't work
1004 */
1005struct inode *new_inode_pseudo(struct super_block *sb)
1006{
1007 struct inode *inode = alloc_inode(sb);
1008
1009 if (inode) {
1010 spin_lock(&inode->i_lock);
1011 inode->i_state = 0;
1012 spin_unlock(&inode->i_lock);
1013 }
1014 return inode;
1015}
1016
1017/**
1018 * new_inode - obtain an inode
1019 * @sb: superblock
1020 *
1021 * Allocates a new inode for given superblock. The default gfp_mask
1022 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
1023 * If HIGHMEM pages are unsuitable or it is known that pages allocated
1024 * for the page cache are not reclaimable or migratable,
1025 * mapping_set_gfp_mask() must be called with suitable flags on the
1026 * newly created inode's mapping
1027 *
1028 */
1029struct inode *new_inode(struct super_block *sb)
1030{
1031 struct inode *inode;
1032
1033 inode = new_inode_pseudo(sb);
1034 if (inode)
1035 inode_sb_list_add(inode);
1036 return inode;
1037}
1038EXPORT_SYMBOL(new_inode);
1039
1040#ifdef CONFIG_DEBUG_LOCK_ALLOC
1041void lockdep_annotate_inode_mutex_key(struct inode *inode)
1042{
1043 if (S_ISDIR(inode->i_mode)) {
1044 struct file_system_type *type = inode->i_sb->s_type;
1045
1046 /* Set new key only if filesystem hasn't already changed it */
1047 if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) {
1048 /*
1049 * ensure nobody is actually holding i_mutex
1050 */
1051 // mutex_destroy(&inode->i_mutex);
1052 init_rwsem(&inode->i_rwsem);
1053 lockdep_set_class(&inode->i_rwsem,
1054 &type->i_mutex_dir_key);
1055 }
1056 }
1057}
1058EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
1059#endif
1060
1061/**
1062 * unlock_new_inode - clear the I_NEW state and wake up any waiters
1063 * @inode: new inode to unlock
1064 *
1065 * Called when the inode is fully initialised to clear the new state of the
1066 * inode and wake up anyone waiting for the inode to finish initialisation.
1067 */
1068void unlock_new_inode(struct inode *inode)
1069{
1070 lockdep_annotate_inode_mutex_key(inode);
1071 spin_lock(&inode->i_lock);
1072 WARN_ON(!(inode->i_state & I_NEW));
1073 inode->i_state &= ~I_NEW & ~I_CREATING;
1074 smp_mb();
1075 wake_up_bit(&inode->i_state, __I_NEW);
1076 spin_unlock(&inode->i_lock);
1077}
1078EXPORT_SYMBOL(unlock_new_inode);
1079
1080void discard_new_inode(struct inode *inode)
1081{
1082 lockdep_annotate_inode_mutex_key(inode);
1083 spin_lock(&inode->i_lock);
1084 WARN_ON(!(inode->i_state & I_NEW));
1085 inode->i_state &= ~I_NEW;
1086 smp_mb();
1087 wake_up_bit(&inode->i_state, __I_NEW);
1088 spin_unlock(&inode->i_lock);
1089 iput(inode);
1090}
1091EXPORT_SYMBOL(discard_new_inode);
1092
1093/**
1094 * lock_two_nondirectories - take two i_mutexes on non-directory objects
1095 *
1096 * Lock any non-NULL argument. Passed objects must not be directories.
1097 * Zero, one or two objects may be locked by this function.
1098 *
1099 * @inode1: first inode to lock
1100 * @inode2: second inode to lock
1101 */
1102void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
1103{
1104 if (inode1)
1105 WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
1106 if (inode2)
1107 WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
1108 if (inode1 > inode2)
1109 swap(inode1, inode2);
1110 if (inode1)
1111 inode_lock(inode1);
1112 if (inode2 && inode2 != inode1)
1113 inode_lock_nested(inode2, I_MUTEX_NONDIR2);
1114}
1115EXPORT_SYMBOL(lock_two_nondirectories);
1116
1117/**
1118 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
1119 * @inode1: first inode to unlock
1120 * @inode2: second inode to unlock
1121 */
1122void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
1123{
1124 if (inode1) {
1125 WARN_ON_ONCE(S_ISDIR(inode1->i_mode));
1126 inode_unlock(inode1);
1127 }
1128 if (inode2 && inode2 != inode1) {
1129 WARN_ON_ONCE(S_ISDIR(inode2->i_mode));
1130 inode_unlock(inode2);
1131 }
1132}
1133EXPORT_SYMBOL(unlock_two_nondirectories);
1134
1135/**
1136 * inode_insert5 - obtain an inode from a mounted file system
1137 * @inode: pre-allocated inode to use for insert to cache
1138 * @hashval: hash value (usually inode number) to get
1139 * @test: callback used for comparisons between inodes
1140 * @set: callback used to initialize a new struct inode
1141 * @data: opaque data pointer to pass to @test and @set
1142 *
1143 * Search for the inode specified by @hashval and @data in the inode cache,
1144 * and if present it is return it with an increased reference count. This is
1145 * a variant of iget5_locked() for callers that don't want to fail on memory
1146 * allocation of inode.
1147 *
1148 * If the inode is not in cache, insert the pre-allocated inode to cache and
1149 * return it locked, hashed, and with the I_NEW flag set. The file system gets
1150 * to fill it in before unlocking it via unlock_new_inode().
1151 *
1152 * Note both @test and @set are called with the inode_hash_lock held, so can't
1153 * sleep.
1154 */
1155struct inode *inode_insert5(struct inode *inode, unsigned long hashval,
1156 int (*test)(struct inode *, void *),
1157 int (*set)(struct inode *, void *), void *data)
1158{
1159 struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
1160 struct inode *old;
1161
1162again:
1163 spin_lock(&inode_hash_lock);
1164 old = find_inode(inode->i_sb, head, test, data);
1165 if (unlikely(old)) {
1166 /*
1167 * Uhhuh, somebody else created the same inode under us.
1168 * Use the old inode instead of the preallocated one.
1169 */
1170 spin_unlock(&inode_hash_lock);
1171 if (IS_ERR(old))
1172 return NULL;
1173 wait_on_inode(old);
1174 if (unlikely(inode_unhashed(old))) {
1175 iput(old);
1176 goto again;
1177 }
1178 return old;
1179 }
1180
1181 if (set && unlikely(set(inode, data))) {
1182 inode = NULL;
1183 goto unlock;
1184 }
1185
1186 /*
1187 * Return the locked inode with I_NEW set, the
1188 * caller is responsible for filling in the contents
1189 */
1190 spin_lock(&inode->i_lock);
1191 inode->i_state |= I_NEW;
1192 hlist_add_head_rcu(&inode->i_hash, head);
1193 spin_unlock(&inode->i_lock);
1194
1195 /*
1196 * Add inode to the sb list if it's not already. It has I_NEW at this
1197 * point, so it should be safe to test i_sb_list locklessly.
1198 */
1199 if (list_empty(&inode->i_sb_list))
1200 inode_sb_list_add(inode);
1201unlock:
1202 spin_unlock(&inode_hash_lock);
1203
1204 return inode;
1205}
1206EXPORT_SYMBOL(inode_insert5);
1207
1208/**
1209 * iget5_locked - obtain an inode from a mounted file system
1210 * @sb: super block of file system
1211 * @hashval: hash value (usually inode number) to get
1212 * @test: callback used for comparisons between inodes
1213 * @set: callback used to initialize a new struct inode
1214 * @data: opaque data pointer to pass to @test and @set
1215 *
1216 * Search for the inode specified by @hashval and @data in the inode cache,
1217 * and if present it is return it with an increased reference count. This is
1218 * a generalized version of iget_locked() for file systems where the inode
1219 * number is not sufficient for unique identification of an inode.
1220 *
1221 * If the inode is not in cache, allocate a new inode and return it locked,
1222 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1223 * before unlocking it via unlock_new_inode().
1224 *
1225 * Note both @test and @set are called with the inode_hash_lock held, so can't
1226 * sleep.
1227 */
1228struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
1229 int (*test)(struct inode *, void *),
1230 int (*set)(struct inode *, void *), void *data)
1231{
1232 struct inode *inode = ilookup5(sb, hashval, test, data);
1233
1234 if (!inode) {
1235 struct inode *new = alloc_inode(sb);
1236
1237 if (new) {
1238 new->i_state = 0;
1239 inode = inode_insert5(new, hashval, test, set, data);
1240 if (unlikely(inode != new))
1241 destroy_inode(new);
1242 }
1243 }
1244 return inode;
1245}
1246EXPORT_SYMBOL(iget5_locked);
1247
1248/**
1249 * iget_locked - obtain an inode from a mounted file system
1250 * @sb: super block of file system
1251 * @ino: inode number to get
1252 *
1253 * Search for the inode specified by @ino in the inode cache and if present
1254 * return it with an increased reference count. This is for file systems
1255 * where the inode number is sufficient for unique identification of an inode.
1256 *
1257 * If the inode is not in cache, allocate a new inode and return it locked,
1258 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1259 * before unlocking it via unlock_new_inode().
1260 */
1261struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1262{
1263 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1264 struct inode *inode;
1265again:
1266 spin_lock(&inode_hash_lock);
1267 inode = find_inode_fast(sb, head, ino);
1268 spin_unlock(&inode_hash_lock);
1269 if (inode) {
1270 if (IS_ERR(inode))
1271 return NULL;
1272 wait_on_inode(inode);
1273 if (unlikely(inode_unhashed(inode))) {
1274 iput(inode);
1275 goto again;
1276 }
1277 return inode;
1278 }
1279
1280 inode = alloc_inode(sb);
1281 if (inode) {
1282 struct inode *old;
1283
1284 spin_lock(&inode_hash_lock);
1285 /* We released the lock, so.. */
1286 old = find_inode_fast(sb, head, ino);
1287 if (!old) {
1288 inode->i_ino = ino;
1289 spin_lock(&inode->i_lock);
1290 inode->i_state = I_NEW;
1291 hlist_add_head_rcu(&inode->i_hash, head);
1292 spin_unlock(&inode->i_lock);
1293 inode_sb_list_add(inode);
1294 spin_unlock(&inode_hash_lock);
1295
1296 /* Return the locked inode with I_NEW set, the
1297 * caller is responsible for filling in the contents
1298 */
1299 return inode;
1300 }
1301
1302 /*
1303 * Uhhuh, somebody else created the same inode under
1304 * us. Use the old inode instead of the one we just
1305 * allocated.
1306 */
1307 spin_unlock(&inode_hash_lock);
1308 destroy_inode(inode);
1309 if (IS_ERR(old))
1310 return NULL;
1311 inode = old;
1312 wait_on_inode(inode);
1313 if (unlikely(inode_unhashed(inode))) {
1314 iput(inode);
1315 goto again;
1316 }
1317 }
1318 return inode;
1319}
1320EXPORT_SYMBOL(iget_locked);
1321
1322/*
1323 * search the inode cache for a matching inode number.
1324 * If we find one, then the inode number we are trying to
1325 * allocate is not unique and so we should not use it.
1326 *
1327 * Returns 1 if the inode number is unique, 0 if it is not.
1328 */
1329static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1330{
1331 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1332 struct inode *inode;
1333
1334 hlist_for_each_entry_rcu(inode, b, i_hash) {
1335 if (inode->i_ino == ino && inode->i_sb == sb)
1336 return 0;
1337 }
1338 return 1;
1339}
1340
1341/**
1342 * iunique - get a unique inode number
1343 * @sb: superblock
1344 * @max_reserved: highest reserved inode number
1345 *
1346 * Obtain an inode number that is unique on the system for a given
1347 * superblock. This is used by file systems that have no natural
1348 * permanent inode numbering system. An inode number is returned that
1349 * is higher than the reserved limit but unique.
1350 *
1351 * BUGS:
1352 * With a large number of inodes live on the file system this function
1353 * currently becomes quite slow.
1354 */
1355ino_t iunique(struct super_block *sb, ino_t max_reserved)
1356{
1357 /*
1358 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1359 * error if st_ino won't fit in target struct field. Use 32bit counter
1360 * here to attempt to avoid that.
1361 */
1362 static DEFINE_SPINLOCK(iunique_lock);
1363 static unsigned int counter;
1364 ino_t res;
1365
1366 rcu_read_lock();
1367 spin_lock(&iunique_lock);
1368 do {
1369 if (counter <= max_reserved)
1370 counter = max_reserved + 1;
1371 res = counter++;
1372 } while (!test_inode_iunique(sb, res));
1373 spin_unlock(&iunique_lock);
1374 rcu_read_unlock();
1375
1376 return res;
1377}
1378EXPORT_SYMBOL(iunique);
1379
1380struct inode *igrab(struct inode *inode)
1381{
1382 spin_lock(&inode->i_lock);
1383 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1384 __iget(inode);
1385 spin_unlock(&inode->i_lock);
1386 } else {
1387 spin_unlock(&inode->i_lock);
1388 /*
1389 * Handle the case where s_op->clear_inode is not been
1390 * called yet, and somebody is calling igrab
1391 * while the inode is getting freed.
1392 */
1393 inode = NULL;
1394 }
1395 return inode;
1396}
1397EXPORT_SYMBOL(igrab);
1398
1399/**
1400 * ilookup5_nowait - search for an inode in the inode cache
1401 * @sb: super block of file system to search
1402 * @hashval: hash value (usually inode number) to search for
1403 * @test: callback used for comparisons between inodes
1404 * @data: opaque data pointer to pass to @test
1405 *
1406 * Search for the inode specified by @hashval and @data in the inode cache.
1407 * If the inode is in the cache, the inode is returned with an incremented
1408 * reference count.
1409 *
1410 * Note: I_NEW is not waited upon so you have to be very careful what you do
1411 * with the returned inode. You probably should be using ilookup5() instead.
1412 *
1413 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1414 */
1415struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1416 int (*test)(struct inode *, void *), void *data)
1417{
1418 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1419 struct inode *inode;
1420
1421 spin_lock(&inode_hash_lock);
1422 inode = find_inode(sb, head, test, data);
1423 spin_unlock(&inode_hash_lock);
1424
1425 return IS_ERR(inode) ? NULL : inode;
1426}
1427EXPORT_SYMBOL(ilookup5_nowait);
1428
1429/**
1430 * ilookup5 - search for an inode in the inode cache
1431 * @sb: super block of file system to search
1432 * @hashval: hash value (usually inode number) to search for
1433 * @test: callback used for comparisons between inodes
1434 * @data: opaque data pointer to pass to @test
1435 *
1436 * Search for the inode specified by @hashval and @data in the inode cache,
1437 * and if the inode is in the cache, return the inode with an incremented
1438 * reference count. Waits on I_NEW before returning the inode.
1439 * returned with an incremented reference count.
1440 *
1441 * This is a generalized version of ilookup() for file systems where the
1442 * inode number is not sufficient for unique identification of an inode.
1443 *
1444 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1445 */
1446struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1447 int (*test)(struct inode *, void *), void *data)
1448{
1449 struct inode *inode;
1450again:
1451 inode = ilookup5_nowait(sb, hashval, test, data);
1452 if (inode) {
1453 wait_on_inode(inode);
1454 if (unlikely(inode_unhashed(inode))) {
1455 iput(inode);
1456 goto again;
1457 }
1458 }
1459 return inode;
1460}
1461EXPORT_SYMBOL(ilookup5);
1462
1463/**
1464 * ilookup - search for an inode in the inode cache
1465 * @sb: super block of file system to search
1466 * @ino: inode number to search for
1467 *
1468 * Search for the inode @ino in the inode cache, and if the inode is in the
1469 * cache, the inode is returned with an incremented reference count.
1470 */
1471struct inode *ilookup(struct super_block *sb, unsigned long ino)
1472{
1473 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1474 struct inode *inode;
1475again:
1476 spin_lock(&inode_hash_lock);
1477 inode = find_inode_fast(sb, head, ino);
1478 spin_unlock(&inode_hash_lock);
1479
1480 if (inode) {
1481 if (IS_ERR(inode))
1482 return NULL;
1483 wait_on_inode(inode);
1484 if (unlikely(inode_unhashed(inode))) {
1485 iput(inode);
1486 goto again;
1487 }
1488 }
1489 return inode;
1490}
1491EXPORT_SYMBOL(ilookup);
1492
1493/**
1494 * find_inode_nowait - find an inode in the inode cache
1495 * @sb: super block of file system to search
1496 * @hashval: hash value (usually inode number) to search for
1497 * @match: callback used for comparisons between inodes
1498 * @data: opaque data pointer to pass to @match
1499 *
1500 * Search for the inode specified by @hashval and @data in the inode
1501 * cache, where the helper function @match will return 0 if the inode
1502 * does not match, 1 if the inode does match, and -1 if the search
1503 * should be stopped. The @match function must be responsible for
1504 * taking the i_lock spin_lock and checking i_state for an inode being
1505 * freed or being initialized, and incrementing the reference count
1506 * before returning 1. It also must not sleep, since it is called with
1507 * the inode_hash_lock spinlock held.
1508 *
1509 * This is a even more generalized version of ilookup5() when the
1510 * function must never block --- find_inode() can block in
1511 * __wait_on_freeing_inode() --- or when the caller can not increment
1512 * the reference count because the resulting iput() might cause an
1513 * inode eviction. The tradeoff is that the @match funtion must be
1514 * very carefully implemented.
1515 */
1516struct inode *find_inode_nowait(struct super_block *sb,
1517 unsigned long hashval,
1518 int (*match)(struct inode *, unsigned long,
1519 void *),
1520 void *data)
1521{
1522 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1523 struct inode *inode, *ret_inode = NULL;
1524 int mval;
1525
1526 spin_lock(&inode_hash_lock);
1527 hlist_for_each_entry(inode, head, i_hash) {
1528 if (inode->i_sb != sb)
1529 continue;
1530 mval = match(inode, hashval, data);
1531 if (mval == 0)
1532 continue;
1533 if (mval == 1)
1534 ret_inode = inode;
1535 goto out;
1536 }
1537out:
1538 spin_unlock(&inode_hash_lock);
1539 return ret_inode;
1540}
1541EXPORT_SYMBOL(find_inode_nowait);
1542
1543/**
1544 * find_inode_rcu - find an inode in the inode cache
1545 * @sb: Super block of file system to search
1546 * @hashval: Key to hash
1547 * @test: Function to test match on an inode
1548 * @data: Data for test function
1549 *
1550 * Search for the inode specified by @hashval and @data in the inode cache,
1551 * where the helper function @test will return 0 if the inode does not match
1552 * and 1 if it does. The @test function must be responsible for taking the
1553 * i_lock spin_lock and checking i_state for an inode being freed or being
1554 * initialized.
1555 *
1556 * If successful, this will return the inode for which the @test function
1557 * returned 1 and NULL otherwise.
1558 *
1559 * The @test function is not permitted to take a ref on any inode presented.
1560 * It is also not permitted to sleep.
1561 *
1562 * The caller must hold the RCU read lock.
1563 */
1564struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
1565 int (*test)(struct inode *, void *), void *data)
1566{
1567 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1568 struct inode *inode;
1569
1570 RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
1571 "suspicious find_inode_rcu() usage");
1572
1573 hlist_for_each_entry_rcu(inode, head, i_hash) {
1574 if (inode->i_sb == sb &&
1575 !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)) &&
1576 test(inode, data))
1577 return inode;
1578 }
1579 return NULL;
1580}
1581EXPORT_SYMBOL(find_inode_rcu);
1582
1583/**
1584 * find_inode_by_ino_rcu - Find an inode in the inode cache
1585 * @sb: Super block of file system to search
1586 * @ino: The inode number to match
1587 *
1588 * Search for the inode specified by @hashval and @data in the inode cache,
1589 * where the helper function @test will return 0 if the inode does not match
1590 * and 1 if it does. The @test function must be responsible for taking the
1591 * i_lock spin_lock and checking i_state for an inode being freed or being
1592 * initialized.
1593 *
1594 * If successful, this will return the inode for which the @test function
1595 * returned 1 and NULL otherwise.
1596 *
1597 * The @test function is not permitted to take a ref on any inode presented.
1598 * It is also not permitted to sleep.
1599 *
1600 * The caller must hold the RCU read lock.
1601 */
1602struct inode *find_inode_by_ino_rcu(struct super_block *sb,
1603 unsigned long ino)
1604{
1605 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1606 struct inode *inode;
1607
1608 RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
1609 "suspicious find_inode_by_ino_rcu() usage");
1610
1611 hlist_for_each_entry_rcu(inode, head, i_hash) {
1612 if (inode->i_ino == ino &&
1613 inode->i_sb == sb &&
1614 !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)))
1615 return inode;
1616 }
1617 return NULL;
1618}
1619EXPORT_SYMBOL(find_inode_by_ino_rcu);
1620
1621int insert_inode_locked(struct inode *inode)
1622{
1623 struct super_block *sb = inode->i_sb;
1624 ino_t ino = inode->i_ino;
1625 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1626
1627 while (1) {
1628 struct inode *old = NULL;
1629 spin_lock(&inode_hash_lock);
1630 hlist_for_each_entry(old, head, i_hash) {
1631 if (old->i_ino != ino)
1632 continue;
1633 if (old->i_sb != sb)
1634 continue;
1635 spin_lock(&old->i_lock);
1636 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1637 spin_unlock(&old->i_lock);
1638 continue;
1639 }
1640 break;
1641 }
1642 if (likely(!old)) {
1643 spin_lock(&inode->i_lock);
1644 inode->i_state |= I_NEW | I_CREATING;
1645 hlist_add_head_rcu(&inode->i_hash, head);
1646 spin_unlock(&inode->i_lock);
1647 spin_unlock(&inode_hash_lock);
1648 return 0;
1649 }
1650 if (unlikely(old->i_state & I_CREATING)) {
1651 spin_unlock(&old->i_lock);
1652 spin_unlock(&inode_hash_lock);
1653 return -EBUSY;
1654 }
1655 __iget(old);
1656 spin_unlock(&old->i_lock);
1657 spin_unlock(&inode_hash_lock);
1658 wait_on_inode(old);
1659 if (unlikely(!inode_unhashed(old))) {
1660 iput(old);
1661 return -EBUSY;
1662 }
1663 iput(old);
1664 }
1665}
1666EXPORT_SYMBOL(insert_inode_locked);
1667
1668int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1669 int (*test)(struct inode *, void *), void *data)
1670{
1671 struct inode *old;
1672
1673 inode->i_state |= I_CREATING;
1674 old = inode_insert5(inode, hashval, test, NULL, data);
1675
1676 if (old != inode) {
1677 iput(old);
1678 return -EBUSY;
1679 }
1680 return 0;
1681}
1682EXPORT_SYMBOL(insert_inode_locked4);
1683
1684
1685int generic_delete_inode(struct inode *inode)
1686{
1687 return 1;
1688}
1689EXPORT_SYMBOL(generic_delete_inode);
1690
1691/*
1692 * Called when we're dropping the last reference
1693 * to an inode.
1694 *
1695 * Call the FS "drop_inode()" function, defaulting to
1696 * the legacy UNIX filesystem behaviour. If it tells
1697 * us to evict inode, do so. Otherwise, retain inode
1698 * in cache if fs is alive, sync and evict if fs is
1699 * shutting down.
1700 */
1701static void iput_final(struct inode *inode)
1702{
1703 struct super_block *sb = inode->i_sb;
1704 const struct super_operations *op = inode->i_sb->s_op;
1705 unsigned long state;
1706 int drop;
1707
1708 WARN_ON(inode->i_state & I_NEW);
1709
1710 if (op->drop_inode)
1711 drop = op->drop_inode(inode);
1712 else
1713 drop = generic_drop_inode(inode);
1714
1715 if (!drop &&
1716 !(inode->i_state & I_DONTCACHE) &&
1717 (sb->s_flags & SB_ACTIVE)) {
1718 __inode_add_lru(inode, true);
1719 spin_unlock(&inode->i_lock);
1720 return;
1721 }
1722
1723 state = inode->i_state;
1724 if (!drop) {
1725 WRITE_ONCE(inode->i_state, state | I_WILL_FREE);
1726 spin_unlock(&inode->i_lock);
1727
1728 write_inode_now(inode, 1);
1729
1730 spin_lock(&inode->i_lock);
1731 state = inode->i_state;
1732 WARN_ON(state & I_NEW);
1733 state &= ~I_WILL_FREE;
1734 }
1735
1736 WRITE_ONCE(inode->i_state, state | I_FREEING);
1737 if (!list_empty(&inode->i_lru))
1738 inode_lru_list_del(inode);
1739 spin_unlock(&inode->i_lock);
1740
1741 evict(inode);
1742}
1743
1744/**
1745 * iput - put an inode
1746 * @inode: inode to put
1747 *
1748 * Puts an inode, dropping its usage count. If the inode use count hits
1749 * zero, the inode is then freed and may also be destroyed.
1750 *
1751 * Consequently, iput() can sleep.
1752 */
1753void iput(struct inode *inode)
1754{
1755 if (!inode)
1756 return;
1757 BUG_ON(inode->i_state & I_CLEAR);
1758retry:
1759 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {
1760 if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) {
1761 atomic_inc(&inode->i_count);
1762 spin_unlock(&inode->i_lock);
1763 trace_writeback_lazytime_iput(inode);
1764 mark_inode_dirty_sync(inode);
1765 goto retry;
1766 }
1767 iput_final(inode);
1768 }
1769}
1770EXPORT_SYMBOL(iput);
1771
1772#ifdef CONFIG_BLOCK
1773/**
1774 * bmap - find a block number in a file
1775 * @inode: inode owning the block number being requested
1776 * @block: pointer containing the block to find
1777 *
1778 * Replaces the value in ``*block`` with the block number on the device holding
1779 * corresponding to the requested block number in the file.
1780 * That is, asked for block 4 of inode 1 the function will replace the
1781 * 4 in ``*block``, with disk block relative to the disk start that holds that
1782 * block of the file.
1783 *
1784 * Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a
1785 * hole, returns 0 and ``*block`` is also set to 0.
1786 */
1787int bmap(struct inode *inode, sector_t *block)
1788{
1789 if (!inode->i_mapping->a_ops->bmap)
1790 return -EINVAL;
1791
1792 *block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block);
1793 return 0;
1794}
1795EXPORT_SYMBOL(bmap);
1796#endif
1797
1798/*
1799 * With relative atime, only update atime if the previous atime is
1800 * earlier than or equal to either the ctime or mtime,
1801 * or if at least a day has passed since the last atime update.
1802 */
1803static bool relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1804 struct timespec64 now)
1805{
1806 struct timespec64 atime, mtime, ctime;
1807
1808 if (!(mnt->mnt_flags & MNT_RELATIME))
1809 return true;
1810 /*
1811 * Is mtime younger than or equal to atime? If yes, update atime:
1812 */
1813 atime = inode_get_atime(inode);
1814 mtime = inode_get_mtime(inode);
1815 if (timespec64_compare(&mtime, &atime) >= 0)
1816 return true;
1817 /*
1818 * Is ctime younger than or equal to atime? If yes, update atime:
1819 */
1820 ctime = inode_get_ctime(inode);
1821 if (timespec64_compare(&ctime, &atime) >= 0)
1822 return true;
1823
1824 /*
1825 * Is the previous atime value older than a day? If yes,
1826 * update atime:
1827 */
1828 if ((long)(now.tv_sec - atime.tv_sec) >= 24*60*60)
1829 return true;
1830 /*
1831 * Good, we can skip the atime update:
1832 */
1833 return false;
1834}
1835
1836/**
1837 * inode_update_timestamps - update the timestamps on the inode
1838 * @inode: inode to be updated
1839 * @flags: S_* flags that needed to be updated
1840 *
1841 * The update_time function is called when an inode's timestamps need to be
1842 * updated for a read or write operation. This function handles updating the
1843 * actual timestamps. It's up to the caller to ensure that the inode is marked
1844 * dirty appropriately.
1845 *
1846 * In the case where any of S_MTIME, S_CTIME, or S_VERSION need to be updated,
1847 * attempt to update all three of them. S_ATIME updates can be handled
1848 * independently of the rest.
1849 *
1850 * Returns a set of S_* flags indicating which values changed.
1851 */
1852int inode_update_timestamps(struct inode *inode, int flags)
1853{
1854 int updated = 0;
1855 struct timespec64 now;
1856
1857 if (flags & (S_MTIME|S_CTIME|S_VERSION)) {
1858 struct timespec64 ctime = inode_get_ctime(inode);
1859 struct timespec64 mtime = inode_get_mtime(inode);
1860
1861 now = inode_set_ctime_current(inode);
1862 if (!timespec64_equal(&now, &ctime))
1863 updated |= S_CTIME;
1864 if (!timespec64_equal(&now, &mtime)) {
1865 inode_set_mtime_to_ts(inode, now);
1866 updated |= S_MTIME;
1867 }
1868 if (IS_I_VERSION(inode) && inode_maybe_inc_iversion(inode, updated))
1869 updated |= S_VERSION;
1870 } else {
1871 now = current_time(inode);
1872 }
1873
1874 if (flags & S_ATIME) {
1875 struct timespec64 atime = inode_get_atime(inode);
1876
1877 if (!timespec64_equal(&now, &atime)) {
1878 inode_set_atime_to_ts(inode, now);
1879 updated |= S_ATIME;
1880 }
1881 }
1882 return updated;
1883}
1884EXPORT_SYMBOL(inode_update_timestamps);
1885
1886/**
1887 * generic_update_time - update the timestamps on the inode
1888 * @inode: inode to be updated
1889 * @flags: S_* flags that needed to be updated
1890 *
1891 * The update_time function is called when an inode's timestamps need to be
1892 * updated for a read or write operation. In the case where any of S_MTIME, S_CTIME,
1893 * or S_VERSION need to be updated we attempt to update all three of them. S_ATIME
1894 * updates can be handled done independently of the rest.
1895 *
1896 * Returns a S_* mask indicating which fields were updated.
1897 */
1898int generic_update_time(struct inode *inode, int flags)
1899{
1900 int updated = inode_update_timestamps(inode, flags);
1901 int dirty_flags = 0;
1902
1903 if (updated & (S_ATIME|S_MTIME|S_CTIME))
1904 dirty_flags = inode->i_sb->s_flags & SB_LAZYTIME ? I_DIRTY_TIME : I_DIRTY_SYNC;
1905 if (updated & S_VERSION)
1906 dirty_flags |= I_DIRTY_SYNC;
1907 __mark_inode_dirty(inode, dirty_flags);
1908 return updated;
1909}
1910EXPORT_SYMBOL(generic_update_time);
1911
1912/*
1913 * This does the actual work of updating an inodes time or version. Must have
1914 * had called mnt_want_write() before calling this.
1915 */
1916int inode_update_time(struct inode *inode, int flags)
1917{
1918 if (inode->i_op->update_time)
1919 return inode->i_op->update_time(inode, flags);
1920 generic_update_time(inode, flags);
1921 return 0;
1922}
1923EXPORT_SYMBOL(inode_update_time);
1924
1925/**
1926 * atime_needs_update - update the access time
1927 * @path: the &struct path to update
1928 * @inode: inode to update
1929 *
1930 * Update the accessed time on an inode and mark it for writeback.
1931 * This function automatically handles read only file systems and media,
1932 * as well as the "noatime" flag and inode specific "noatime" markers.
1933 */
1934bool atime_needs_update(const struct path *path, struct inode *inode)
1935{
1936 struct vfsmount *mnt = path->mnt;
1937 struct timespec64 now, atime;
1938
1939 if (inode->i_flags & S_NOATIME)
1940 return false;
1941
1942 /* Atime updates will likely cause i_uid and i_gid to be written
1943 * back improprely if their true value is unknown to the vfs.
1944 */
1945 if (HAS_UNMAPPED_ID(mnt_idmap(mnt), inode))
1946 return false;
1947
1948 if (IS_NOATIME(inode))
1949 return false;
1950 if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode))
1951 return false;
1952
1953 if (mnt->mnt_flags & MNT_NOATIME)
1954 return false;
1955 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1956 return false;
1957
1958 now = current_time(inode);
1959
1960 if (!relatime_need_update(mnt, inode, now))
1961 return false;
1962
1963 atime = inode_get_atime(inode);
1964 if (timespec64_equal(&atime, &now))
1965 return false;
1966
1967 return true;
1968}
1969
1970void touch_atime(const struct path *path)
1971{
1972 struct vfsmount *mnt = path->mnt;
1973 struct inode *inode = d_inode(path->dentry);
1974
1975 if (!atime_needs_update(path, inode))
1976 return;
1977
1978 if (!sb_start_write_trylock(inode->i_sb))
1979 return;
1980
1981 if (mnt_get_write_access(mnt) != 0)
1982 goto skip_update;
1983 /*
1984 * File systems can error out when updating inodes if they need to
1985 * allocate new space to modify an inode (such is the case for
1986 * Btrfs), but since we touch atime while walking down the path we
1987 * really don't care if we failed to update the atime of the file,
1988 * so just ignore the return value.
1989 * We may also fail on filesystems that have the ability to make parts
1990 * of the fs read only, e.g. subvolumes in Btrfs.
1991 */
1992 inode_update_time(inode, S_ATIME);
1993 mnt_put_write_access(mnt);
1994skip_update:
1995 sb_end_write(inode->i_sb);
1996}
1997EXPORT_SYMBOL(touch_atime);
1998
1999/*
2000 * Return mask of changes for notify_change() that need to be done as a
2001 * response to write or truncate. Return 0 if nothing has to be changed.
2002 * Negative value on error (change should be denied).
2003 */
2004int dentry_needs_remove_privs(struct mnt_idmap *idmap,
2005 struct dentry *dentry)
2006{
2007 struct inode *inode = d_inode(dentry);
2008 int mask = 0;
2009 int ret;
2010
2011 if (IS_NOSEC(inode))
2012 return 0;
2013
2014 mask = setattr_should_drop_suidgid(idmap, inode);
2015 ret = security_inode_need_killpriv(dentry);
2016 if (ret < 0)
2017 return ret;
2018 if (ret)
2019 mask |= ATTR_KILL_PRIV;
2020 return mask;
2021}
2022
2023static int __remove_privs(struct mnt_idmap *idmap,
2024 struct dentry *dentry, int kill)
2025{
2026 struct iattr newattrs;
2027
2028 newattrs.ia_valid = ATTR_FORCE | kill;
2029 /*
2030 * Note we call this on write, so notify_change will not
2031 * encounter any conflicting delegations:
2032 */
2033 return notify_change(idmap, dentry, &newattrs, NULL);
2034}
2035
2036int file_remove_privs_flags(struct file *file, unsigned int flags)
2037{
2038 struct dentry *dentry = file_dentry(file);
2039 struct inode *inode = file_inode(file);
2040 int error = 0;
2041 int kill;
2042
2043 if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
2044 return 0;
2045
2046 kill = dentry_needs_remove_privs(file_mnt_idmap(file), dentry);
2047 if (kill < 0)
2048 return kill;
2049
2050 if (kill) {
2051 if (flags & IOCB_NOWAIT)
2052 return -EAGAIN;
2053
2054 error = __remove_privs(file_mnt_idmap(file), dentry, kill);
2055 }
2056
2057 if (!error)
2058 inode_has_no_xattr(inode);
2059 return error;
2060}
2061EXPORT_SYMBOL_GPL(file_remove_privs_flags);
2062
2063/**
2064 * file_remove_privs - remove special file privileges (suid, capabilities)
2065 * @file: file to remove privileges from
2066 *
2067 * When file is modified by a write or truncation ensure that special
2068 * file privileges are removed.
2069 *
2070 * Return: 0 on success, negative errno on failure.
2071 */
2072int file_remove_privs(struct file *file)
2073{
2074 return file_remove_privs_flags(file, 0);
2075}
2076EXPORT_SYMBOL(file_remove_privs);
2077
2078static int inode_needs_update_time(struct inode *inode)
2079{
2080 int sync_it = 0;
2081 struct timespec64 now = current_time(inode);
2082 struct timespec64 ts;
2083
2084 /* First try to exhaust all avenues to not sync */
2085 if (IS_NOCMTIME(inode))
2086 return 0;
2087
2088 ts = inode_get_mtime(inode);
2089 if (!timespec64_equal(&ts, &now))
2090 sync_it = S_MTIME;
2091
2092 ts = inode_get_ctime(inode);
2093 if (!timespec64_equal(&ts, &now))
2094 sync_it |= S_CTIME;
2095
2096 if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode))
2097 sync_it |= S_VERSION;
2098
2099 return sync_it;
2100}
2101
2102static int __file_update_time(struct file *file, int sync_mode)
2103{
2104 int ret = 0;
2105 struct inode *inode = file_inode(file);
2106
2107 /* try to update time settings */
2108 if (!mnt_get_write_access_file(file)) {
2109 ret = inode_update_time(inode, sync_mode);
2110 mnt_put_write_access_file(file);
2111 }
2112
2113 return ret;
2114}
2115
2116/**
2117 * file_update_time - update mtime and ctime time
2118 * @file: file accessed
2119 *
2120 * Update the mtime and ctime members of an inode and mark the inode for
2121 * writeback. Note that this function is meant exclusively for usage in
2122 * the file write path of filesystems, and filesystems may choose to
2123 * explicitly ignore updates via this function with the _NOCMTIME inode
2124 * flag, e.g. for network filesystem where these imestamps are handled
2125 * by the server. This can return an error for file systems who need to
2126 * allocate space in order to update an inode.
2127 *
2128 * Return: 0 on success, negative errno on failure.
2129 */
2130int file_update_time(struct file *file)
2131{
2132 int ret;
2133 struct inode *inode = file_inode(file);
2134
2135 ret = inode_needs_update_time(inode);
2136 if (ret <= 0)
2137 return ret;
2138
2139 return __file_update_time(file, ret);
2140}
2141EXPORT_SYMBOL(file_update_time);
2142
2143/**
2144 * file_modified_flags - handle mandated vfs changes when modifying a file
2145 * @file: file that was modified
2146 * @flags: kiocb flags
2147 *
2148 * When file has been modified ensure that special
2149 * file privileges are removed and time settings are updated.
2150 *
2151 * If IOCB_NOWAIT is set, special file privileges will not be removed and
2152 * time settings will not be updated. It will return -EAGAIN.
2153 *
2154 * Context: Caller must hold the file's inode lock.
2155 *
2156 * Return: 0 on success, negative errno on failure.
2157 */
2158static int file_modified_flags(struct file *file, int flags)
2159{
2160 int ret;
2161 struct inode *inode = file_inode(file);
2162
2163 /*
2164 * Clear the security bits if the process is not being run by root.
2165 * This keeps people from modifying setuid and setgid binaries.
2166 */
2167 ret = file_remove_privs_flags(file, flags);
2168 if (ret)
2169 return ret;
2170
2171 if (unlikely(file->f_mode & FMODE_NOCMTIME))
2172 return 0;
2173
2174 ret = inode_needs_update_time(inode);
2175 if (ret <= 0)
2176 return ret;
2177 if (flags & IOCB_NOWAIT)
2178 return -EAGAIN;
2179
2180 return __file_update_time(file, ret);
2181}
2182
2183/**
2184 * file_modified - handle mandated vfs changes when modifying a file
2185 * @file: file that was modified
2186 *
2187 * When file has been modified ensure that special
2188 * file privileges are removed and time settings are updated.
2189 *
2190 * Context: Caller must hold the file's inode lock.
2191 *
2192 * Return: 0 on success, negative errno on failure.
2193 */
2194int file_modified(struct file *file)
2195{
2196 return file_modified_flags(file, 0);
2197}
2198EXPORT_SYMBOL(file_modified);
2199
2200/**
2201 * kiocb_modified - handle mandated vfs changes when modifying a file
2202 * @iocb: iocb that was modified
2203 *
2204 * When file has been modified ensure that special
2205 * file privileges are removed and time settings are updated.
2206 *
2207 * Context: Caller must hold the file's inode lock.
2208 *
2209 * Return: 0 on success, negative errno on failure.
2210 */
2211int kiocb_modified(struct kiocb *iocb)
2212{
2213 return file_modified_flags(iocb->ki_filp, iocb->ki_flags);
2214}
2215EXPORT_SYMBOL_GPL(kiocb_modified);
2216
2217int inode_needs_sync(struct inode *inode)
2218{
2219 if (IS_SYNC(inode))
2220 return 1;
2221 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
2222 return 1;
2223 return 0;
2224}
2225EXPORT_SYMBOL(inode_needs_sync);
2226
2227/*
2228 * If we try to find an inode in the inode hash while it is being
2229 * deleted, we have to wait until the filesystem completes its
2230 * deletion before reporting that it isn't found. This function waits
2231 * until the deletion _might_ have completed. Callers are responsible
2232 * to recheck inode state.
2233 *
2234 * It doesn't matter if I_NEW is not set initially, a call to
2235 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
2236 * will DTRT.
2237 */
2238static void __wait_on_freeing_inode(struct inode *inode)
2239{
2240 wait_queue_head_t *wq;
2241 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
2242 wq = bit_waitqueue(&inode->i_state, __I_NEW);
2243 prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
2244 spin_unlock(&inode->i_lock);
2245 spin_unlock(&inode_hash_lock);
2246 schedule();
2247 finish_wait(wq, &wait.wq_entry);
2248 spin_lock(&inode_hash_lock);
2249}
2250
2251static __initdata unsigned long ihash_entries;
2252static int __init set_ihash_entries(char *str)
2253{
2254 if (!str)
2255 return 0;
2256 ihash_entries = simple_strtoul(str, &str, 0);
2257 return 1;
2258}
2259__setup("ihash_entries=", set_ihash_entries);
2260
2261/*
2262 * Initialize the waitqueues and inode hash table.
2263 */
2264void __init inode_init_early(void)
2265{
2266 /* If hashes are distributed across NUMA nodes, defer
2267 * hash allocation until vmalloc space is available.
2268 */
2269 if (hashdist)
2270 return;
2271
2272 inode_hashtable =
2273 alloc_large_system_hash("Inode-cache",
2274 sizeof(struct hlist_head),
2275 ihash_entries,
2276 14,
2277 HASH_EARLY | HASH_ZERO,
2278 &i_hash_shift,
2279 &i_hash_mask,
2280 0,
2281 0);
2282}
2283
2284void __init inode_init(void)
2285{
2286 /* inode slab cache */
2287 inode_cachep = kmem_cache_create("inode_cache",
2288 sizeof(struct inode),
2289 0,
2290 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
2291 SLAB_ACCOUNT),
2292 init_once);
2293
2294 /* Hash may have been set up in inode_init_early */
2295 if (!hashdist)
2296 return;
2297
2298 inode_hashtable =
2299 alloc_large_system_hash("Inode-cache",
2300 sizeof(struct hlist_head),
2301 ihash_entries,
2302 14,
2303 HASH_ZERO,
2304 &i_hash_shift,
2305 &i_hash_mask,
2306 0,
2307 0);
2308}
2309
2310void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
2311{
2312 inode->i_mode = mode;
2313 if (S_ISCHR(mode)) {
2314 inode->i_fop = &def_chr_fops;
2315 inode->i_rdev = rdev;
2316 } else if (S_ISBLK(mode)) {
2317 if (IS_ENABLED(CONFIG_BLOCK))
2318 inode->i_fop = &def_blk_fops;
2319 inode->i_rdev = rdev;
2320 } else if (S_ISFIFO(mode))
2321 inode->i_fop = &pipefifo_fops;
2322 else if (S_ISSOCK(mode))
2323 ; /* leave it no_open_fops */
2324 else
2325 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
2326 " inode %s:%lu\n", mode, inode->i_sb->s_id,
2327 inode->i_ino);
2328}
2329EXPORT_SYMBOL(init_special_inode);
2330
2331/**
2332 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
2333 * @idmap: idmap of the mount the inode was created from
2334 * @inode: New inode
2335 * @dir: Directory inode
2336 * @mode: mode of the new inode
2337 *
2338 * If the inode has been created through an idmapped mount the idmap of
2339 * the vfsmount must be passed through @idmap. This function will then take
2340 * care to map the inode according to @idmap before checking permissions
2341 * and initializing i_uid and i_gid. On non-idmapped mounts or if permission
2342 * checking is to be performed on the raw inode simply pass @nop_mnt_idmap.
2343 */
2344void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode,
2345 const struct inode *dir, umode_t mode)
2346{
2347 inode_fsuid_set(inode, idmap);
2348 if (dir && dir->i_mode & S_ISGID) {
2349 inode->i_gid = dir->i_gid;
2350
2351 /* Directories are special, and always inherit S_ISGID */
2352 if (S_ISDIR(mode))
2353 mode |= S_ISGID;
2354 } else
2355 inode_fsgid_set(inode, idmap);
2356 inode->i_mode = mode;
2357}
2358EXPORT_SYMBOL(inode_init_owner);
2359
2360/**
2361 * inode_owner_or_capable - check current task permissions to inode
2362 * @idmap: idmap of the mount the inode was found from
2363 * @inode: inode being checked
2364 *
2365 * Return true if current either has CAP_FOWNER in a namespace with the
2366 * inode owner uid mapped, or owns the file.
2367 *
2368 * If the inode has been found through an idmapped mount the idmap of
2369 * the vfsmount must be passed through @idmap. This function will then take
2370 * care to map the inode according to @idmap before checking permissions.
2371 * On non-idmapped mounts or if permission checking is to be performed on the
2372 * raw inode simply pass @nop_mnt_idmap.
2373 */
2374bool inode_owner_or_capable(struct mnt_idmap *idmap,
2375 const struct inode *inode)
2376{
2377 vfsuid_t vfsuid;
2378 struct user_namespace *ns;
2379
2380 vfsuid = i_uid_into_vfsuid(idmap, inode);
2381 if (vfsuid_eq_kuid(vfsuid, current_fsuid()))
2382 return true;
2383
2384 ns = current_user_ns();
2385 if (vfsuid_has_mapping(ns, vfsuid) && ns_capable(ns, CAP_FOWNER))
2386 return true;
2387 return false;
2388}
2389EXPORT_SYMBOL(inode_owner_or_capable);
2390
2391/*
2392 * Direct i/o helper functions
2393 */
2394static void __inode_dio_wait(struct inode *inode)
2395{
2396 wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
2397 DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
2398
2399 do {
2400 prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE);
2401 if (atomic_read(&inode->i_dio_count))
2402 schedule();
2403 } while (atomic_read(&inode->i_dio_count));
2404 finish_wait(wq, &q.wq_entry);
2405}
2406
2407/**
2408 * inode_dio_wait - wait for outstanding DIO requests to finish
2409 * @inode: inode to wait for
2410 *
2411 * Waits for all pending direct I/O requests to finish so that we can
2412 * proceed with a truncate or equivalent operation.
2413 *
2414 * Must be called under a lock that serializes taking new references
2415 * to i_dio_count, usually by inode->i_mutex.
2416 */
2417void inode_dio_wait(struct inode *inode)
2418{
2419 if (atomic_read(&inode->i_dio_count))
2420 __inode_dio_wait(inode);
2421}
2422EXPORT_SYMBOL(inode_dio_wait);
2423
2424/*
2425 * inode_set_flags - atomically set some inode flags
2426 *
2427 * Note: the caller should be holding i_mutex, or else be sure that
2428 * they have exclusive access to the inode structure (i.e., while the
2429 * inode is being instantiated). The reason for the cmpxchg() loop
2430 * --- which wouldn't be necessary if all code paths which modify
2431 * i_flags actually followed this rule, is that there is at least one
2432 * code path which doesn't today so we use cmpxchg() out of an abundance
2433 * of caution.
2434 *
2435 * In the long run, i_mutex is overkill, and we should probably look
2436 * at using the i_lock spinlock to protect i_flags, and then make sure
2437 * it is so documented in include/linux/fs.h and that all code follows
2438 * the locking convention!!
2439 */
2440void inode_set_flags(struct inode *inode, unsigned int flags,
2441 unsigned int mask)
2442{
2443 WARN_ON_ONCE(flags & ~mask);
2444 set_mask_bits(&inode->i_flags, mask, flags);
2445}
2446EXPORT_SYMBOL(inode_set_flags);
2447
2448void inode_nohighmem(struct inode *inode)
2449{
2450 mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
2451}
2452EXPORT_SYMBOL(inode_nohighmem);
2453
2454/**
2455 * timestamp_truncate - Truncate timespec to a granularity
2456 * @t: Timespec
2457 * @inode: inode being updated
2458 *
2459 * Truncate a timespec to the granularity supported by the fs
2460 * containing the inode. Always rounds down. gran must
2461 * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
2462 */
2463struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode)
2464{
2465 struct super_block *sb = inode->i_sb;
2466 unsigned int gran = sb->s_time_gran;
2467
2468 t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max);
2469 if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min))
2470 t.tv_nsec = 0;
2471
2472 /* Avoid division in the common cases 1 ns and 1 s. */
2473 if (gran == 1)
2474 ; /* nothing */
2475 else if (gran == NSEC_PER_SEC)
2476 t.tv_nsec = 0;
2477 else if (gran > 1 && gran < NSEC_PER_SEC)
2478 t.tv_nsec -= t.tv_nsec % gran;
2479 else
2480 WARN(1, "invalid file time granularity: %u", gran);
2481 return t;
2482}
2483EXPORT_SYMBOL(timestamp_truncate);
2484
2485/**
2486 * current_time - Return FS time
2487 * @inode: inode.
2488 *
2489 * Return the current time truncated to the time granularity supported by
2490 * the fs.
2491 *
2492 * Note that inode and inode->sb cannot be NULL.
2493 * Otherwise, the function warns and returns time without truncation.
2494 */
2495struct timespec64 current_time(struct inode *inode)
2496{
2497 struct timespec64 now;
2498
2499 ktime_get_coarse_real_ts64(&now);
2500 return timestamp_truncate(now, inode);
2501}
2502EXPORT_SYMBOL(current_time);
2503
2504/**
2505 * inode_set_ctime_current - set the ctime to current_time
2506 * @inode: inode
2507 *
2508 * Set the inode->i_ctime to the current value for the inode. Returns
2509 * the current value that was assigned to i_ctime.
2510 */
2511struct timespec64 inode_set_ctime_current(struct inode *inode)
2512{
2513 struct timespec64 now = current_time(inode);
2514
2515 inode_set_ctime_to_ts(inode, now);
2516 return now;
2517}
2518EXPORT_SYMBOL(inode_set_ctime_current);
2519
2520/**
2521 * in_group_or_capable - check whether caller is CAP_FSETID privileged
2522 * @idmap: idmap of the mount @inode was found from
2523 * @inode: inode to check
2524 * @vfsgid: the new/current vfsgid of @inode
2525 *
2526 * Check wether @vfsgid is in the caller's group list or if the caller is
2527 * privileged with CAP_FSETID over @inode. This can be used to determine
2528 * whether the setgid bit can be kept or must be dropped.
2529 *
2530 * Return: true if the caller is sufficiently privileged, false if not.
2531 */
2532bool in_group_or_capable(struct mnt_idmap *idmap,
2533 const struct inode *inode, vfsgid_t vfsgid)
2534{
2535 if (vfsgid_in_group_p(vfsgid))
2536 return true;
2537 if (capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))
2538 return true;
2539 return false;
2540}
2541
2542/**
2543 * mode_strip_sgid - handle the sgid bit for non-directories
2544 * @idmap: idmap of the mount the inode was created from
2545 * @dir: parent directory inode
2546 * @mode: mode of the file to be created in @dir
2547 *
2548 * If the @mode of the new file has both the S_ISGID and S_IXGRP bit
2549 * raised and @dir has the S_ISGID bit raised ensure that the caller is
2550 * either in the group of the parent directory or they have CAP_FSETID
2551 * in their user namespace and are privileged over the parent directory.
2552 * In all other cases, strip the S_ISGID bit from @mode.
2553 *
2554 * Return: the new mode to use for the file
2555 */
2556umode_t mode_strip_sgid(struct mnt_idmap *idmap,
2557 const struct inode *dir, umode_t mode)
2558{
2559 if ((mode & (S_ISGID | S_IXGRP)) != (S_ISGID | S_IXGRP))
2560 return mode;
2561 if (S_ISDIR(mode) || !dir || !(dir->i_mode & S_ISGID))
2562 return mode;
2563 if (in_group_or_capable(idmap, dir, i_gid_into_vfsgid(idmap, dir)))
2564 return mode;
2565 return mode & ~S_ISGID;
2566}
2567EXPORT_SYMBOL(mode_strip_sgid);