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