2 * (C) 1997 Linus Torvalds
3 * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation)
5 #include <linux/export.h>
8 #include <linux/backing-dev.h>
9 #include <linux/hash.h>
10 #include <linux/swap.h>
11 #include <linux/security.h>
12 #include <linux/cdev.h>
13 #include <linux/bootmem.h>
14 #include <linux/fsnotify.h>
15 #include <linux/mount.h>
16 #include <linux/posix_acl.h>
17 #include <linux/prefetch.h>
18 #include <linux/buffer_head.h> /* for inode_has_buffers */
19 #include <linux/ratelimit.h>
20 #include <linux/list_lru.h>
21 #include <trace/events/writeback.h>
25 * Inode locking rules:
27 * inode->i_lock protects:
28 * inode->i_state, inode->i_hash, __iget()
29 * Inode LRU list locks protect:
30 * inode->i_sb->s_inode_lru, inode->i_lru
31 * inode->i_sb->s_inode_list_lock protects:
32 * inode->i_sb->s_inodes, inode->i_sb_list
33 * bdi->wb.list_lock protects:
34 * bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list
35 * inode_hash_lock protects:
36 * inode_hashtable, inode->i_hash
40 * inode->i_sb->s_inode_list_lock
42 * Inode LRU list locks
48 * inode->i_sb->s_inode_list_lock
55 static unsigned int i_hash_mask __read_mostly
;
56 static unsigned int i_hash_shift __read_mostly
;
57 static struct hlist_head
*inode_hashtable __read_mostly
;
58 static __cacheline_aligned_in_smp
DEFINE_SPINLOCK(inode_hash_lock
);
61 * Empty aops. Can be used for the cases where the user does not
62 * define any of the address_space operations.
64 const struct address_space_operations empty_aops
= {
66 EXPORT_SYMBOL(empty_aops
);
69 * Statistics gathering..
71 struct inodes_stat_t inodes_stat
;
73 static DEFINE_PER_CPU(unsigned long, nr_inodes
);
74 static DEFINE_PER_CPU(unsigned long, nr_unused
);
76 static struct kmem_cache
*inode_cachep __read_mostly
;
78 static long get_nr_inodes(void)
82 for_each_possible_cpu(i
)
83 sum
+= per_cpu(nr_inodes
, i
);
84 return sum
< 0 ? 0 : sum
;
87 static inline long get_nr_inodes_unused(void)
91 for_each_possible_cpu(i
)
92 sum
+= per_cpu(nr_unused
, i
);
93 return sum
< 0 ? 0 : sum
;
96 long get_nr_dirty_inodes(void)
98 /* not actually dirty inodes, but a wild approximation */
99 long nr_dirty
= get_nr_inodes() - get_nr_inodes_unused();
100 return nr_dirty
> 0 ? nr_dirty
: 0;
104 * Handle nr_inode sysctl
107 int proc_nr_inodes(struct ctl_table
*table
, int write
,
108 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
110 inodes_stat
.nr_inodes
= get_nr_inodes();
111 inodes_stat
.nr_unused
= get_nr_inodes_unused();
112 return proc_doulongvec_minmax(table
, write
, buffer
, lenp
, ppos
);
116 static int no_open(struct inode
*inode
, struct file
*file
)
122 * inode_init_always - perform inode structure initialisation
123 * @sb: superblock inode belongs to
124 * @inode: inode to initialise
126 * These are initializations that need to be done on every inode
127 * allocation as the fields are not initialised by slab allocation.
129 int inode_init_always(struct super_block
*sb
, struct inode
*inode
)
131 static const struct inode_operations empty_iops
;
132 static const struct file_operations no_open_fops
= {.open
= no_open
};
133 struct address_space
*const mapping
= &inode
->i_data
;
136 inode
->i_blkbits
= sb
->s_blocksize_bits
;
138 atomic_set(&inode
->i_count
, 1);
139 inode
->i_op
= &empty_iops
;
140 inode
->i_fop
= &no_open_fops
;
141 inode
->__i_nlink
= 1;
142 inode
->i_opflags
= 0;
144 inode
->i_opflags
|= IOP_XATTR
;
145 i_uid_write(inode
, 0);
146 i_gid_write(inode
, 0);
147 atomic_set(&inode
->i_writecount
, 0);
149 inode
->i_write_hint
= WRITE_LIFE_NOT_SET
;
152 inode
->i_generation
= 0;
153 inode
->i_pipe
= NULL
;
154 inode
->i_bdev
= NULL
;
155 inode
->i_cdev
= NULL
;
156 inode
->i_link
= NULL
;
157 inode
->i_dir_seq
= 0;
159 inode
->dirtied_when
= 0;
161 #ifdef CONFIG_CGROUP_WRITEBACK
162 inode
->i_wb_frn_winner
= 0;
163 inode
->i_wb_frn_avg_time
= 0;
164 inode
->i_wb_frn_history
= 0;
167 if (security_inode_alloc(inode
))
169 spin_lock_init(&inode
->i_lock
);
170 lockdep_set_class(&inode
->i_lock
, &sb
->s_type
->i_lock_key
);
172 init_rwsem(&inode
->i_rwsem
);
173 lockdep_set_class(&inode
->i_rwsem
, &sb
->s_type
->i_mutex_key
);
175 atomic_set(&inode
->i_dio_count
, 0);
177 mapping
->a_ops
= &empty_aops
;
178 mapping
->host
= inode
;
181 atomic_set(&mapping
->i_mmap_writable
, 0);
182 mapping_set_gfp_mask(mapping
, GFP_HIGHUSER_MOVABLE
);
183 mapping
->private_data
= NULL
;
184 mapping
->writeback_index
= 0;
185 inode
->i_private
= NULL
;
186 inode
->i_mapping
= mapping
;
187 INIT_HLIST_HEAD(&inode
->i_dentry
); /* buggered by rcu freeing */
188 #ifdef CONFIG_FS_POSIX_ACL
189 inode
->i_acl
= inode
->i_default_acl
= ACL_NOT_CACHED
;
192 #ifdef CONFIG_FSNOTIFY
193 inode
->i_fsnotify_mask
= 0;
195 inode
->i_flctx
= NULL
;
196 this_cpu_inc(nr_inodes
);
202 EXPORT_SYMBOL(inode_init_always
);
204 static struct inode
*alloc_inode(struct super_block
*sb
)
208 if (sb
->s_op
->alloc_inode
)
209 inode
= sb
->s_op
->alloc_inode(sb
);
211 inode
= kmem_cache_alloc(inode_cachep
, GFP_KERNEL
);
216 if (unlikely(inode_init_always(sb
, inode
))) {
217 if (inode
->i_sb
->s_op
->destroy_inode
)
218 inode
->i_sb
->s_op
->destroy_inode(inode
);
220 kmem_cache_free(inode_cachep
, inode
);
227 void free_inode_nonrcu(struct inode
*inode
)
229 kmem_cache_free(inode_cachep
, inode
);
231 EXPORT_SYMBOL(free_inode_nonrcu
);
233 void __destroy_inode(struct inode
*inode
)
235 BUG_ON(inode_has_buffers(inode
));
236 inode_detach_wb(inode
);
237 security_inode_free(inode
);
238 fsnotify_inode_delete(inode
);
239 locks_free_lock_context(inode
);
240 if (!inode
->i_nlink
) {
241 WARN_ON(atomic_long_read(&inode
->i_sb
->s_remove_count
) == 0);
242 atomic_long_dec(&inode
->i_sb
->s_remove_count
);
245 #ifdef CONFIG_FS_POSIX_ACL
246 if (inode
->i_acl
&& !is_uncached_acl(inode
->i_acl
))
247 posix_acl_release(inode
->i_acl
);
248 if (inode
->i_default_acl
&& !is_uncached_acl(inode
->i_default_acl
))
249 posix_acl_release(inode
->i_default_acl
);
251 this_cpu_dec(nr_inodes
);
253 EXPORT_SYMBOL(__destroy_inode
);
255 static void i_callback(struct rcu_head
*head
)
257 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
258 kmem_cache_free(inode_cachep
, inode
);
261 static void destroy_inode(struct inode
*inode
)
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
);
268 call_rcu(&inode
->i_rcu
, i_callback
);
272 * drop_nlink - directly drop an inode's link count
275 * This is a low-level filesystem helper to replace any
276 * direct filesystem manipulation of i_nlink. In cases
277 * where we are attempting to track writes to the
278 * filesystem, a decrement to zero means an imminent
279 * write when the file is truncated and actually unlinked
282 void drop_nlink(struct inode
*inode
)
284 WARN_ON(inode
->i_nlink
== 0);
287 atomic_long_inc(&inode
->i_sb
->s_remove_count
);
289 EXPORT_SYMBOL(drop_nlink
);
292 * clear_nlink - directly zero an inode's link count
295 * This is a low-level filesystem helper to replace any
296 * direct filesystem manipulation of i_nlink. See
297 * drop_nlink() for why we care about i_nlink hitting zero.
299 void clear_nlink(struct inode
*inode
)
301 if (inode
->i_nlink
) {
302 inode
->__i_nlink
= 0;
303 atomic_long_inc(&inode
->i_sb
->s_remove_count
);
306 EXPORT_SYMBOL(clear_nlink
);
309 * set_nlink - directly set an inode's link count
311 * @nlink: new nlink (should be non-zero)
313 * This is a low-level filesystem helper to replace any
314 * direct filesystem manipulation of i_nlink.
316 void set_nlink(struct inode
*inode
, unsigned int nlink
)
321 /* Yes, some filesystems do change nlink from zero to one */
322 if (inode
->i_nlink
== 0)
323 atomic_long_dec(&inode
->i_sb
->s_remove_count
);
325 inode
->__i_nlink
= nlink
;
328 EXPORT_SYMBOL(set_nlink
);
331 * inc_nlink - directly increment an inode's link count
334 * This is a low-level filesystem helper to replace any
335 * direct filesystem manipulation of i_nlink. Currently,
336 * it is only here for parity with dec_nlink().
338 void inc_nlink(struct inode
*inode
)
340 if (unlikely(inode
->i_nlink
== 0)) {
341 WARN_ON(!(inode
->i_state
& I_LINKABLE
));
342 atomic_long_dec(&inode
->i_sb
->s_remove_count
);
347 EXPORT_SYMBOL(inc_nlink
);
349 void address_space_init_once(struct address_space
*mapping
)
351 memset(mapping
, 0, sizeof(*mapping
));
352 INIT_RADIX_TREE(&mapping
->page_tree
, GFP_ATOMIC
| __GFP_ACCOUNT
);
353 spin_lock_init(&mapping
->tree_lock
);
354 init_rwsem(&mapping
->i_mmap_rwsem
);
355 INIT_LIST_HEAD(&mapping
->private_list
);
356 spin_lock_init(&mapping
->private_lock
);
357 mapping
->i_mmap
= RB_ROOT_CACHED
;
359 EXPORT_SYMBOL(address_space_init_once
);
362 * These are initializations that only need to be done
363 * once, because the fields are idempotent across use
364 * of the inode, so let the slab aware of that.
366 void inode_init_once(struct inode
*inode
)
368 memset(inode
, 0, sizeof(*inode
));
369 INIT_HLIST_NODE(&inode
->i_hash
);
370 INIT_LIST_HEAD(&inode
->i_devices
);
371 INIT_LIST_HEAD(&inode
->i_io_list
);
372 INIT_LIST_HEAD(&inode
->i_wb_list
);
373 INIT_LIST_HEAD(&inode
->i_lru
);
374 address_space_init_once(&inode
->i_data
);
375 i_size_ordered_init(inode
);
377 EXPORT_SYMBOL(inode_init_once
);
379 static void init_once(void *foo
)
381 struct inode
*inode
= (struct inode
*) foo
;
383 inode_init_once(inode
);
387 * inode->i_lock must be held
389 void __iget(struct inode
*inode
)
391 atomic_inc(&inode
->i_count
);
395 * get additional reference to inode; caller must already hold one.
397 void ihold(struct inode
*inode
)
399 WARN_ON(atomic_inc_return(&inode
->i_count
) < 2);
401 EXPORT_SYMBOL(ihold
);
403 static void inode_lru_list_add(struct inode
*inode
)
405 if (list_lru_add(&inode
->i_sb
->s_inode_lru
, &inode
->i_lru
))
406 this_cpu_inc(nr_unused
);
408 inode
->i_state
|= I_REFERENCED
;
412 * Add inode to LRU if needed (inode is unused and clean).
414 * Needs inode->i_lock held.
416 void inode_add_lru(struct inode
*inode
)
418 if (!(inode
->i_state
& (I_DIRTY_ALL
| I_SYNC
|
419 I_FREEING
| I_WILL_FREE
)) &&
420 !atomic_read(&inode
->i_count
) && inode
->i_sb
->s_flags
& SB_ACTIVE
)
421 inode_lru_list_add(inode
);
425 static void inode_lru_list_del(struct inode
*inode
)
428 if (list_lru_del(&inode
->i_sb
->s_inode_lru
, &inode
->i_lru
))
429 this_cpu_dec(nr_unused
);
433 * inode_sb_list_add - add inode to the superblock list of inodes
434 * @inode: inode to add
436 void inode_sb_list_add(struct inode
*inode
)
438 spin_lock(&inode
->i_sb
->s_inode_list_lock
);
439 list_add(&inode
->i_sb_list
, &inode
->i_sb
->s_inodes
);
440 spin_unlock(&inode
->i_sb
->s_inode_list_lock
);
442 EXPORT_SYMBOL_GPL(inode_sb_list_add
);
444 static inline void inode_sb_list_del(struct inode
*inode
)
446 if (!list_empty(&inode
->i_sb_list
)) {
447 spin_lock(&inode
->i_sb
->s_inode_list_lock
);
448 list_del_init(&inode
->i_sb_list
);
449 spin_unlock(&inode
->i_sb
->s_inode_list_lock
);
453 static unsigned long hash(struct super_block
*sb
, unsigned long hashval
)
457 tmp
= (hashval
* (unsigned long)sb
) ^ (GOLDEN_RATIO_PRIME
+ hashval
) /
459 tmp
= tmp
^ ((tmp
^ GOLDEN_RATIO_PRIME
) >> i_hash_shift
);
460 return tmp
& i_hash_mask
;
464 * __insert_inode_hash - hash an inode
465 * @inode: unhashed inode
466 * @hashval: unsigned long value used to locate this object in the
469 * Add an inode to the inode hash for this superblock.
471 void __insert_inode_hash(struct inode
*inode
, unsigned long hashval
)
473 struct hlist_head
*b
= inode_hashtable
+ hash(inode
->i_sb
, hashval
);
475 spin_lock(&inode_hash_lock
);
476 spin_lock(&inode
->i_lock
);
477 hlist_add_head(&inode
->i_hash
, b
);
478 spin_unlock(&inode
->i_lock
);
479 spin_unlock(&inode_hash_lock
);
481 EXPORT_SYMBOL(__insert_inode_hash
);
484 * __remove_inode_hash - remove an inode from the hash
485 * @inode: inode to unhash
487 * Remove an inode from the superblock.
489 void __remove_inode_hash(struct inode
*inode
)
491 spin_lock(&inode_hash_lock
);
492 spin_lock(&inode
->i_lock
);
493 hlist_del_init(&inode
->i_hash
);
494 spin_unlock(&inode
->i_lock
);
495 spin_unlock(&inode_hash_lock
);
497 EXPORT_SYMBOL(__remove_inode_hash
);
499 void clear_inode(struct inode
*inode
)
503 * We have to cycle tree_lock here because reclaim can be still in the
504 * process of removing the last page (in __delete_from_page_cache())
505 * and we must not free mapping under it.
507 spin_lock_irq(&inode
->i_data
.tree_lock
);
508 BUG_ON(inode
->i_data
.nrpages
);
509 BUG_ON(inode
->i_data
.nrexceptional
);
510 spin_unlock_irq(&inode
->i_data
.tree_lock
);
511 BUG_ON(!list_empty(&inode
->i_data
.private_list
));
512 BUG_ON(!(inode
->i_state
& I_FREEING
));
513 BUG_ON(inode
->i_state
& I_CLEAR
);
514 BUG_ON(!list_empty(&inode
->i_wb_list
));
515 /* don't need i_lock here, no concurrent mods to i_state */
516 inode
->i_state
= I_FREEING
| I_CLEAR
;
518 EXPORT_SYMBOL(clear_inode
);
521 * Free the inode passed in, removing it from the lists it is still connected
522 * to. We remove any pages still attached to the inode and wait for any IO that
523 * is still in progress before finally destroying the inode.
525 * An inode must already be marked I_FREEING so that we avoid the inode being
526 * moved back onto lists if we race with other code that manipulates the lists
527 * (e.g. writeback_single_inode). The caller is responsible for setting this.
529 * An inode must already be removed from the LRU list before being evicted from
530 * the cache. This should occur atomically with setting the I_FREEING state
531 * flag, so no inodes here should ever be on the LRU when being evicted.
533 static void evict(struct inode
*inode
)
535 const struct super_operations
*op
= inode
->i_sb
->s_op
;
537 BUG_ON(!(inode
->i_state
& I_FREEING
));
538 BUG_ON(!list_empty(&inode
->i_lru
));
540 if (!list_empty(&inode
->i_io_list
))
541 inode_io_list_del(inode
);
543 inode_sb_list_del(inode
);
546 * Wait for flusher thread to be done with the inode so that filesystem
547 * does not start destroying it while writeback is still running. Since
548 * the inode has I_FREEING set, flusher thread won't start new work on
549 * the inode. We just have to wait for running writeback to finish.
551 inode_wait_for_writeback(inode
);
553 if (op
->evict_inode
) {
554 op
->evict_inode(inode
);
556 truncate_inode_pages_final(&inode
->i_data
);
559 if (S_ISBLK(inode
->i_mode
) && inode
->i_bdev
)
561 if (S_ISCHR(inode
->i_mode
) && inode
->i_cdev
)
564 remove_inode_hash(inode
);
566 spin_lock(&inode
->i_lock
);
567 wake_up_bit(&inode
->i_state
, __I_NEW
);
568 BUG_ON(inode
->i_state
!= (I_FREEING
| I_CLEAR
));
569 spin_unlock(&inode
->i_lock
);
571 destroy_inode(inode
);
575 * dispose_list - dispose of the contents of a local list
576 * @head: the head of the list to free
578 * Dispose-list gets a local list with local inodes in it, so it doesn't
579 * need to worry about list corruption and SMP locks.
581 static void dispose_list(struct list_head
*head
)
583 while (!list_empty(head
)) {
586 inode
= list_first_entry(head
, struct inode
, i_lru
);
587 list_del_init(&inode
->i_lru
);
595 * evict_inodes - evict all evictable inodes for a superblock
596 * @sb: superblock to operate on
598 * Make sure that no inodes with zero refcount are retained. This is
599 * called by superblock shutdown after having SB_ACTIVE flag removed,
600 * so any inode reaching zero refcount during or after that call will
601 * be immediately evicted.
603 void evict_inodes(struct super_block
*sb
)
605 struct inode
*inode
, *next
;
609 spin_lock(&sb
->s_inode_list_lock
);
610 list_for_each_entry_safe(inode
, next
, &sb
->s_inodes
, i_sb_list
) {
611 if (atomic_read(&inode
->i_count
))
614 spin_lock(&inode
->i_lock
);
615 if (inode
->i_state
& (I_NEW
| I_FREEING
| I_WILL_FREE
)) {
616 spin_unlock(&inode
->i_lock
);
620 inode
->i_state
|= I_FREEING
;
621 inode_lru_list_del(inode
);
622 spin_unlock(&inode
->i_lock
);
623 list_add(&inode
->i_lru
, &dispose
);
626 * We can have a ton of inodes to evict at unmount time given
627 * enough memory, check to see if we need to go to sleep for a
628 * bit so we don't livelock.
630 if (need_resched()) {
631 spin_unlock(&sb
->s_inode_list_lock
);
633 dispose_list(&dispose
);
637 spin_unlock(&sb
->s_inode_list_lock
);
639 dispose_list(&dispose
);
641 EXPORT_SYMBOL_GPL(evict_inodes
);
644 * invalidate_inodes - attempt to free all inodes on a superblock
645 * @sb: superblock to operate on
646 * @kill_dirty: flag to guide handling of dirty inodes
648 * Attempts to free all inodes for a given superblock. If there were any
649 * busy inodes return a non-zero value, else zero.
650 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
653 int invalidate_inodes(struct super_block
*sb
, bool kill_dirty
)
656 struct inode
*inode
, *next
;
660 spin_lock(&sb
->s_inode_list_lock
);
661 list_for_each_entry_safe(inode
, next
, &sb
->s_inodes
, i_sb_list
) {
662 spin_lock(&inode
->i_lock
);
663 if (inode
->i_state
& (I_NEW
| I_FREEING
| I_WILL_FREE
)) {
664 spin_unlock(&inode
->i_lock
);
667 if (inode
->i_state
& I_DIRTY_ALL
&& !kill_dirty
) {
668 spin_unlock(&inode
->i_lock
);
672 if (atomic_read(&inode
->i_count
)) {
673 spin_unlock(&inode
->i_lock
);
678 inode
->i_state
|= I_FREEING
;
679 inode_lru_list_del(inode
);
680 spin_unlock(&inode
->i_lock
);
681 list_add(&inode
->i_lru
, &dispose
);
682 if (need_resched()) {
683 spin_unlock(&sb
->s_inode_list_lock
);
685 dispose_list(&dispose
);
689 spin_unlock(&sb
->s_inode_list_lock
);
691 dispose_list(&dispose
);
697 * Isolate the inode from the LRU in preparation for freeing it.
699 * Any inodes which are pinned purely because of attached pagecache have their
700 * pagecache removed. If the inode has metadata buffers attached to
701 * mapping->private_list then try to remove them.
703 * If the inode has the I_REFERENCED flag set, then it means that it has been
704 * used recently - the flag is set in iput_final(). When we encounter such an
705 * inode, clear the flag and move it to the back of the LRU so it gets another
706 * pass through the LRU before it gets reclaimed. This is necessary because of
707 * the fact we are doing lazy LRU updates to minimise lock contention so the
708 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
709 * with this flag set because they are the inodes that are out of order.
711 static enum lru_status
inode_lru_isolate(struct list_head
*item
,
712 struct list_lru_one
*lru
, spinlock_t
*lru_lock
, void *arg
)
714 struct list_head
*freeable
= arg
;
715 struct inode
*inode
= container_of(item
, struct inode
, i_lru
);
718 * we are inverting the lru lock/inode->i_lock here, so use a trylock.
719 * If we fail to get the lock, just skip it.
721 if (!spin_trylock(&inode
->i_lock
))
725 * Referenced or dirty inodes are still in use. Give them another pass
726 * through the LRU as we canot reclaim them now.
728 if (atomic_read(&inode
->i_count
) ||
729 (inode
->i_state
& ~I_REFERENCED
)) {
730 list_lru_isolate(lru
, &inode
->i_lru
);
731 spin_unlock(&inode
->i_lock
);
732 this_cpu_dec(nr_unused
);
736 /* recently referenced inodes get one more pass */
737 if (inode
->i_state
& I_REFERENCED
) {
738 inode
->i_state
&= ~I_REFERENCED
;
739 spin_unlock(&inode
->i_lock
);
743 if (inode_has_buffers(inode
) || inode
->i_data
.nrpages
) {
745 spin_unlock(&inode
->i_lock
);
746 spin_unlock(lru_lock
);
747 if (remove_inode_buffers(inode
)) {
749 reap
= invalidate_mapping_pages(&inode
->i_data
, 0, -1);
750 if (current_is_kswapd())
751 __count_vm_events(KSWAPD_INODESTEAL
, reap
);
753 __count_vm_events(PGINODESTEAL
, reap
);
754 if (current
->reclaim_state
)
755 current
->reclaim_state
->reclaimed_slab
+= reap
;
762 WARN_ON(inode
->i_state
& I_NEW
);
763 inode
->i_state
|= I_FREEING
;
764 list_lru_isolate_move(lru
, &inode
->i_lru
, freeable
);
765 spin_unlock(&inode
->i_lock
);
767 this_cpu_dec(nr_unused
);
772 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
773 * This is called from the superblock shrinker function with a number of inodes
774 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
775 * then are freed outside inode_lock by dispose_list().
777 long prune_icache_sb(struct super_block
*sb
, struct shrink_control
*sc
)
782 freed
= list_lru_shrink_walk(&sb
->s_inode_lru
, sc
,
783 inode_lru_isolate
, &freeable
);
784 dispose_list(&freeable
);
788 static void __wait_on_freeing_inode(struct inode
*inode
);
790 * Called with the inode lock held.
792 static struct inode
*find_inode(struct super_block
*sb
,
793 struct hlist_head
*head
,
794 int (*test
)(struct inode
*, void *),
797 struct inode
*inode
= NULL
;
800 hlist_for_each_entry(inode
, head
, i_hash
) {
801 if (inode
->i_sb
!= sb
)
803 if (!test(inode
, data
))
805 spin_lock(&inode
->i_lock
);
806 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
807 __wait_on_freeing_inode(inode
);
811 spin_unlock(&inode
->i_lock
);
818 * find_inode_fast is the fast path version of find_inode, see the comment at
819 * iget_locked for details.
821 static struct inode
*find_inode_fast(struct super_block
*sb
,
822 struct hlist_head
*head
, unsigned long ino
)
824 struct inode
*inode
= NULL
;
827 hlist_for_each_entry(inode
, head
, i_hash
) {
828 if (inode
->i_ino
!= ino
)
830 if (inode
->i_sb
!= sb
)
832 spin_lock(&inode
->i_lock
);
833 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
834 __wait_on_freeing_inode(inode
);
838 spin_unlock(&inode
->i_lock
);
845 * Each cpu owns a range of LAST_INO_BATCH numbers.
846 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
847 * to renew the exhausted range.
849 * This does not significantly increase overflow rate because every CPU can
850 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
851 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
852 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
853 * overflow rate by 2x, which does not seem too significant.
855 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
856 * error if st_ino won't fit in target struct field. Use 32bit counter
857 * here to attempt to avoid that.
859 #define LAST_INO_BATCH 1024
860 static DEFINE_PER_CPU(unsigned int, last_ino
);
862 unsigned int get_next_ino(void)
864 unsigned int *p
= &get_cpu_var(last_ino
);
865 unsigned int res
= *p
;
868 if (unlikely((res
& (LAST_INO_BATCH
-1)) == 0)) {
869 static atomic_t shared_last_ino
;
870 int next
= atomic_add_return(LAST_INO_BATCH
, &shared_last_ino
);
872 res
= next
- LAST_INO_BATCH
;
877 /* get_next_ino should not provide a 0 inode number */
881 put_cpu_var(last_ino
);
884 EXPORT_SYMBOL(get_next_ino
);
887 * new_inode_pseudo - obtain an inode
890 * Allocates a new inode for given superblock.
891 * Inode wont be chained in superblock s_inodes list
893 * - fs can't be unmount
894 * - quotas, fsnotify, writeback can't work
896 struct inode
*new_inode_pseudo(struct super_block
*sb
)
898 struct inode
*inode
= alloc_inode(sb
);
901 spin_lock(&inode
->i_lock
);
903 spin_unlock(&inode
->i_lock
);
904 INIT_LIST_HEAD(&inode
->i_sb_list
);
910 * new_inode - obtain an inode
913 * Allocates a new inode for given superblock. The default gfp_mask
914 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
915 * If HIGHMEM pages are unsuitable or it is known that pages allocated
916 * for the page cache are not reclaimable or migratable,
917 * mapping_set_gfp_mask() must be called with suitable flags on the
918 * newly created inode's mapping
921 struct inode
*new_inode(struct super_block
*sb
)
925 spin_lock_prefetch(&sb
->s_inode_list_lock
);
927 inode
= new_inode_pseudo(sb
);
929 inode_sb_list_add(inode
);
932 EXPORT_SYMBOL(new_inode
);
934 #ifdef CONFIG_DEBUG_LOCK_ALLOC
935 void lockdep_annotate_inode_mutex_key(struct inode
*inode
)
937 if (S_ISDIR(inode
->i_mode
)) {
938 struct file_system_type
*type
= inode
->i_sb
->s_type
;
940 /* Set new key only if filesystem hasn't already changed it */
941 if (lockdep_match_class(&inode
->i_rwsem
, &type
->i_mutex_key
)) {
943 * ensure nobody is actually holding i_mutex
945 // mutex_destroy(&inode->i_mutex);
946 init_rwsem(&inode
->i_rwsem
);
947 lockdep_set_class(&inode
->i_rwsem
,
948 &type
->i_mutex_dir_key
);
952 EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key
);
956 * unlock_new_inode - clear the I_NEW state and wake up any waiters
957 * @inode: new inode to unlock
959 * Called when the inode is fully initialised to clear the new state of the
960 * inode and wake up anyone waiting for the inode to finish initialisation.
962 void unlock_new_inode(struct inode
*inode
)
964 lockdep_annotate_inode_mutex_key(inode
);
965 spin_lock(&inode
->i_lock
);
966 WARN_ON(!(inode
->i_state
& I_NEW
));
967 inode
->i_state
&= ~I_NEW
;
969 wake_up_bit(&inode
->i_state
, __I_NEW
);
970 spin_unlock(&inode
->i_lock
);
972 EXPORT_SYMBOL(unlock_new_inode
);
975 * lock_two_nondirectories - take two i_mutexes on non-directory objects
977 * Lock any non-NULL argument that is not a directory.
978 * Zero, one or two objects may be locked by this function.
980 * @inode1: first inode to lock
981 * @inode2: second inode to lock
983 void lock_two_nondirectories(struct inode
*inode1
, struct inode
*inode2
)
986 swap(inode1
, inode2
);
988 if (inode1
&& !S_ISDIR(inode1
->i_mode
))
990 if (inode2
&& !S_ISDIR(inode2
->i_mode
) && inode2
!= inode1
)
991 inode_lock_nested(inode2
, I_MUTEX_NONDIR2
);
993 EXPORT_SYMBOL(lock_two_nondirectories
);
996 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
997 * @inode1: first inode to unlock
998 * @inode2: second inode to unlock
1000 void unlock_two_nondirectories(struct inode
*inode1
, struct inode
*inode2
)
1002 if (inode1
&& !S_ISDIR(inode1
->i_mode
))
1003 inode_unlock(inode1
);
1004 if (inode2
&& !S_ISDIR(inode2
->i_mode
) && inode2
!= inode1
)
1005 inode_unlock(inode2
);
1007 EXPORT_SYMBOL(unlock_two_nondirectories
);
1010 * iget5_locked - obtain an inode from a mounted file system
1011 * @sb: super block of file system
1012 * @hashval: hash value (usually inode number) to get
1013 * @test: callback used for comparisons between inodes
1014 * @set: callback used to initialize a new struct inode
1015 * @data: opaque data pointer to pass to @test and @set
1017 * Search for the inode specified by @hashval and @data in the inode cache,
1018 * and if present it is return it with an increased reference count. This is
1019 * a generalized version of iget_locked() for file systems where the inode
1020 * number is not sufficient for unique identification of an inode.
1022 * If the inode is not in cache, allocate a new inode and return it locked,
1023 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1024 * before unlocking it via unlock_new_inode().
1026 * Note both @test and @set are called with the inode_hash_lock held, so can't
1029 struct inode
*iget5_locked(struct super_block
*sb
, unsigned long hashval
,
1030 int (*test
)(struct inode
*, void *),
1031 int (*set
)(struct inode
*, void *), void *data
)
1033 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1034 struct inode
*inode
;
1036 spin_lock(&inode_hash_lock
);
1037 inode
= find_inode(sb
, head
, test
, data
);
1038 spin_unlock(&inode_hash_lock
);
1041 wait_on_inode(inode
);
1042 if (unlikely(inode_unhashed(inode
))) {
1049 inode
= alloc_inode(sb
);
1053 spin_lock(&inode_hash_lock
);
1054 /* We released the lock, so.. */
1055 old
= find_inode(sb
, head
, test
, data
);
1057 if (set(inode
, data
))
1060 spin_lock(&inode
->i_lock
);
1061 inode
->i_state
= I_NEW
;
1062 hlist_add_head(&inode
->i_hash
, head
);
1063 spin_unlock(&inode
->i_lock
);
1064 inode_sb_list_add(inode
);
1065 spin_unlock(&inode_hash_lock
);
1067 /* Return the locked inode with I_NEW set, the
1068 * caller is responsible for filling in the contents
1074 * Uhhuh, somebody else created the same inode under
1075 * us. Use the old inode instead of the one we just
1078 spin_unlock(&inode_hash_lock
);
1079 destroy_inode(inode
);
1081 wait_on_inode(inode
);
1082 if (unlikely(inode_unhashed(inode
))) {
1090 spin_unlock(&inode_hash_lock
);
1091 destroy_inode(inode
);
1094 EXPORT_SYMBOL(iget5_locked
);
1097 * iget_locked - obtain an inode from a mounted file system
1098 * @sb: super block of file system
1099 * @ino: inode number to get
1101 * Search for the inode specified by @ino in the inode cache and if present
1102 * return it with an increased reference count. This is for file systems
1103 * where the inode number is sufficient for unique identification of an inode.
1105 * If the inode is not in cache, allocate a new inode and return it locked,
1106 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1107 * before unlocking it via unlock_new_inode().
1109 struct inode
*iget_locked(struct super_block
*sb
, unsigned long ino
)
1111 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1112 struct inode
*inode
;
1114 spin_lock(&inode_hash_lock
);
1115 inode
= find_inode_fast(sb
, head
, ino
);
1116 spin_unlock(&inode_hash_lock
);
1118 wait_on_inode(inode
);
1119 if (unlikely(inode_unhashed(inode
))) {
1126 inode
= alloc_inode(sb
);
1130 spin_lock(&inode_hash_lock
);
1131 /* We released the lock, so.. */
1132 old
= find_inode_fast(sb
, head
, ino
);
1135 spin_lock(&inode
->i_lock
);
1136 inode
->i_state
= I_NEW
;
1137 hlist_add_head(&inode
->i_hash
, head
);
1138 spin_unlock(&inode
->i_lock
);
1139 inode_sb_list_add(inode
);
1140 spin_unlock(&inode_hash_lock
);
1142 /* Return the locked inode with I_NEW set, the
1143 * caller is responsible for filling in the contents
1149 * Uhhuh, somebody else created the same inode under
1150 * us. Use the old inode instead of the one we just
1153 spin_unlock(&inode_hash_lock
);
1154 destroy_inode(inode
);
1156 wait_on_inode(inode
);
1157 if (unlikely(inode_unhashed(inode
))) {
1164 EXPORT_SYMBOL(iget_locked
);
1167 * search the inode cache for a matching inode number.
1168 * If we find one, then the inode number we are trying to
1169 * allocate is not unique and so we should not use it.
1171 * Returns 1 if the inode number is unique, 0 if it is not.
1173 static int test_inode_iunique(struct super_block
*sb
, unsigned long ino
)
1175 struct hlist_head
*b
= inode_hashtable
+ hash(sb
, ino
);
1176 struct inode
*inode
;
1178 spin_lock(&inode_hash_lock
);
1179 hlist_for_each_entry(inode
, b
, i_hash
) {
1180 if (inode
->i_ino
== ino
&& inode
->i_sb
== sb
) {
1181 spin_unlock(&inode_hash_lock
);
1185 spin_unlock(&inode_hash_lock
);
1191 * iunique - get a unique inode number
1193 * @max_reserved: highest reserved inode number
1195 * Obtain an inode number that is unique on the system for a given
1196 * superblock. This is used by file systems that have no natural
1197 * permanent inode numbering system. An inode number is returned that
1198 * is higher than the reserved limit but unique.
1201 * With a large number of inodes live on the file system this function
1202 * currently becomes quite slow.
1204 ino_t
iunique(struct super_block
*sb
, ino_t max_reserved
)
1207 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1208 * error if st_ino won't fit in target struct field. Use 32bit counter
1209 * here to attempt to avoid that.
1211 static DEFINE_SPINLOCK(iunique_lock
);
1212 static unsigned int counter
;
1215 spin_lock(&iunique_lock
);
1217 if (counter
<= max_reserved
)
1218 counter
= max_reserved
+ 1;
1220 } while (!test_inode_iunique(sb
, res
));
1221 spin_unlock(&iunique_lock
);
1225 EXPORT_SYMBOL(iunique
);
1227 struct inode
*igrab(struct inode
*inode
)
1229 spin_lock(&inode
->i_lock
);
1230 if (!(inode
->i_state
& (I_FREEING
|I_WILL_FREE
))) {
1232 spin_unlock(&inode
->i_lock
);
1234 spin_unlock(&inode
->i_lock
);
1236 * Handle the case where s_op->clear_inode is not been
1237 * called yet, and somebody is calling igrab
1238 * while the inode is getting freed.
1244 EXPORT_SYMBOL(igrab
);
1247 * ilookup5_nowait - search for an inode in the inode cache
1248 * @sb: super block of file system to search
1249 * @hashval: hash value (usually inode number) to search for
1250 * @test: callback used for comparisons between inodes
1251 * @data: opaque data pointer to pass to @test
1253 * Search for the inode specified by @hashval and @data in the inode cache.
1254 * If the inode is in the cache, the inode is returned with an incremented
1257 * Note: I_NEW is not waited upon so you have to be very careful what you do
1258 * with the returned inode. You probably should be using ilookup5() instead.
1260 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1262 struct inode
*ilookup5_nowait(struct super_block
*sb
, unsigned long hashval
,
1263 int (*test
)(struct inode
*, void *), void *data
)
1265 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1266 struct inode
*inode
;
1268 spin_lock(&inode_hash_lock
);
1269 inode
= find_inode(sb
, head
, test
, data
);
1270 spin_unlock(&inode_hash_lock
);
1274 EXPORT_SYMBOL(ilookup5_nowait
);
1277 * ilookup5 - search for an inode in the inode cache
1278 * @sb: super block of file system to search
1279 * @hashval: hash value (usually inode number) to search for
1280 * @test: callback used for comparisons between inodes
1281 * @data: opaque data pointer to pass to @test
1283 * Search for the inode specified by @hashval and @data in the inode cache,
1284 * and if the inode is in the cache, return the inode with an incremented
1285 * reference count. Waits on I_NEW before returning the inode.
1286 * returned with an incremented reference count.
1288 * This is a generalized version of ilookup() for file systems where the
1289 * inode number is not sufficient for unique identification of an inode.
1291 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1293 struct inode
*ilookup5(struct super_block
*sb
, unsigned long hashval
,
1294 int (*test
)(struct inode
*, void *), void *data
)
1296 struct inode
*inode
;
1298 inode
= ilookup5_nowait(sb
, hashval
, test
, data
);
1300 wait_on_inode(inode
);
1301 if (unlikely(inode_unhashed(inode
))) {
1308 EXPORT_SYMBOL(ilookup5
);
1311 * ilookup - search for an inode in the inode cache
1312 * @sb: super block of file system to search
1313 * @ino: inode number to search for
1315 * Search for the inode @ino in the inode cache, and if the inode is in the
1316 * cache, the inode is returned with an incremented reference count.
1318 struct inode
*ilookup(struct super_block
*sb
, unsigned long ino
)
1320 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1321 struct inode
*inode
;
1323 spin_lock(&inode_hash_lock
);
1324 inode
= find_inode_fast(sb
, head
, ino
);
1325 spin_unlock(&inode_hash_lock
);
1328 wait_on_inode(inode
);
1329 if (unlikely(inode_unhashed(inode
))) {
1336 EXPORT_SYMBOL(ilookup
);
1339 * find_inode_nowait - find an inode in the inode cache
1340 * @sb: super block of file system to search
1341 * @hashval: hash value (usually inode number) to search for
1342 * @match: callback used for comparisons between inodes
1343 * @data: opaque data pointer to pass to @match
1345 * Search for the inode specified by @hashval and @data in the inode
1346 * cache, where the helper function @match will return 0 if the inode
1347 * does not match, 1 if the inode does match, and -1 if the search
1348 * should be stopped. The @match function must be responsible for
1349 * taking the i_lock spin_lock and checking i_state for an inode being
1350 * freed or being initialized, and incrementing the reference count
1351 * before returning 1. It also must not sleep, since it is called with
1352 * the inode_hash_lock spinlock held.
1354 * This is a even more generalized version of ilookup5() when the
1355 * function must never block --- find_inode() can block in
1356 * __wait_on_freeing_inode() --- or when the caller can not increment
1357 * the reference count because the resulting iput() might cause an
1358 * inode eviction. The tradeoff is that the @match funtion must be
1359 * very carefully implemented.
1361 struct inode
*find_inode_nowait(struct super_block
*sb
,
1362 unsigned long hashval
,
1363 int (*match
)(struct inode
*, unsigned long,
1367 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1368 struct inode
*inode
, *ret_inode
= NULL
;
1371 spin_lock(&inode_hash_lock
);
1372 hlist_for_each_entry(inode
, head
, i_hash
) {
1373 if (inode
->i_sb
!= sb
)
1375 mval
= match(inode
, hashval
, data
);
1383 spin_unlock(&inode_hash_lock
);
1386 EXPORT_SYMBOL(find_inode_nowait
);
1388 int insert_inode_locked(struct inode
*inode
)
1390 struct super_block
*sb
= inode
->i_sb
;
1391 ino_t ino
= inode
->i_ino
;
1392 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1395 struct inode
*old
= NULL
;
1396 spin_lock(&inode_hash_lock
);
1397 hlist_for_each_entry(old
, head
, i_hash
) {
1398 if (old
->i_ino
!= ino
)
1400 if (old
->i_sb
!= sb
)
1402 spin_lock(&old
->i_lock
);
1403 if (old
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
1404 spin_unlock(&old
->i_lock
);
1410 spin_lock(&inode
->i_lock
);
1411 inode
->i_state
|= I_NEW
;
1412 hlist_add_head(&inode
->i_hash
, head
);
1413 spin_unlock(&inode
->i_lock
);
1414 spin_unlock(&inode_hash_lock
);
1418 spin_unlock(&old
->i_lock
);
1419 spin_unlock(&inode_hash_lock
);
1421 if (unlikely(!inode_unhashed(old
))) {
1428 EXPORT_SYMBOL(insert_inode_locked
);
1430 int insert_inode_locked4(struct inode
*inode
, unsigned long hashval
,
1431 int (*test
)(struct inode
*, void *), void *data
)
1433 struct super_block
*sb
= inode
->i_sb
;
1434 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1437 struct inode
*old
= NULL
;
1439 spin_lock(&inode_hash_lock
);
1440 hlist_for_each_entry(old
, head
, i_hash
) {
1441 if (old
->i_sb
!= sb
)
1443 if (!test(old
, data
))
1445 spin_lock(&old
->i_lock
);
1446 if (old
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
1447 spin_unlock(&old
->i_lock
);
1453 spin_lock(&inode
->i_lock
);
1454 inode
->i_state
|= I_NEW
;
1455 hlist_add_head(&inode
->i_hash
, head
);
1456 spin_unlock(&inode
->i_lock
);
1457 spin_unlock(&inode_hash_lock
);
1461 spin_unlock(&old
->i_lock
);
1462 spin_unlock(&inode_hash_lock
);
1464 if (unlikely(!inode_unhashed(old
))) {
1471 EXPORT_SYMBOL(insert_inode_locked4
);
1474 int generic_delete_inode(struct inode
*inode
)
1478 EXPORT_SYMBOL(generic_delete_inode
);
1481 * Called when we're dropping the last reference
1484 * Call the FS "drop_inode()" function, defaulting to
1485 * the legacy UNIX filesystem behaviour. If it tells
1486 * us to evict inode, do so. Otherwise, retain inode
1487 * in cache if fs is alive, sync and evict if fs is
1490 static void iput_final(struct inode
*inode
)
1492 struct super_block
*sb
= inode
->i_sb
;
1493 const struct super_operations
*op
= inode
->i_sb
->s_op
;
1496 WARN_ON(inode
->i_state
& I_NEW
);
1499 drop
= op
->drop_inode(inode
);
1501 drop
= generic_drop_inode(inode
);
1503 if (!drop
&& (sb
->s_flags
& SB_ACTIVE
)) {
1504 inode_add_lru(inode
);
1505 spin_unlock(&inode
->i_lock
);
1510 inode
->i_state
|= I_WILL_FREE
;
1511 spin_unlock(&inode
->i_lock
);
1512 write_inode_now(inode
, 1);
1513 spin_lock(&inode
->i_lock
);
1514 WARN_ON(inode
->i_state
& I_NEW
);
1515 inode
->i_state
&= ~I_WILL_FREE
;
1518 inode
->i_state
|= I_FREEING
;
1519 if (!list_empty(&inode
->i_lru
))
1520 inode_lru_list_del(inode
);
1521 spin_unlock(&inode
->i_lock
);
1527 * iput - put an inode
1528 * @inode: inode to put
1530 * Puts an inode, dropping its usage count. If the inode use count hits
1531 * zero, the inode is then freed and may also be destroyed.
1533 * Consequently, iput() can sleep.
1535 void iput(struct inode
*inode
)
1539 BUG_ON(inode
->i_state
& I_CLEAR
);
1541 if (atomic_dec_and_lock(&inode
->i_count
, &inode
->i_lock
)) {
1542 if (inode
->i_nlink
&& (inode
->i_state
& I_DIRTY_TIME
)) {
1543 atomic_inc(&inode
->i_count
);
1544 inode
->i_state
&= ~I_DIRTY_TIME
;
1545 spin_unlock(&inode
->i_lock
);
1546 trace_writeback_lazytime_iput(inode
);
1547 mark_inode_dirty_sync(inode
);
1553 EXPORT_SYMBOL(iput
);
1556 * bmap - find a block number in a file
1557 * @inode: inode of file
1558 * @block: block to find
1560 * Returns the block number on the device holding the inode that
1561 * is the disk block number for the block of the file requested.
1562 * That is, asked for block 4 of inode 1 the function will return the
1563 * disk block relative to the disk start that holds that block of the
1566 sector_t
bmap(struct inode
*inode
, sector_t block
)
1569 if (inode
->i_mapping
->a_ops
->bmap
)
1570 res
= inode
->i_mapping
->a_ops
->bmap(inode
->i_mapping
, block
);
1573 EXPORT_SYMBOL(bmap
);
1576 * Update times in overlayed inode from underlying real inode
1578 static void update_ovl_inode_times(struct dentry
*dentry
, struct inode
*inode
,
1581 struct dentry
*upperdentry
;
1584 * Nothing to do if in rcu or if non-overlayfs
1586 if (rcu
|| likely(!(dentry
->d_flags
& DCACHE_OP_REAL
)))
1589 upperdentry
= d_real(dentry
, NULL
, 0, D_REAL_UPPER
);
1592 * If file is on lower then we can't update atime, so no worries about
1593 * stale mtime/ctime.
1596 struct inode
*realinode
= d_inode(upperdentry
);
1598 if ((!timespec_equal(&inode
->i_mtime
, &realinode
->i_mtime
) ||
1599 !timespec_equal(&inode
->i_ctime
, &realinode
->i_ctime
))) {
1600 inode
->i_mtime
= realinode
->i_mtime
;
1601 inode
->i_ctime
= realinode
->i_ctime
;
1607 * With relative atime, only update atime if the previous atime is
1608 * earlier than either the ctime or mtime or if at least a day has
1609 * passed since the last atime update.
1611 static int relatime_need_update(const struct path
*path
, struct inode
*inode
,
1612 struct timespec now
, bool rcu
)
1615 if (!(path
->mnt
->mnt_flags
& MNT_RELATIME
))
1618 update_ovl_inode_times(path
->dentry
, inode
, rcu
);
1620 * Is mtime younger than atime? If yes, update atime:
1622 if (timespec_compare(&inode
->i_mtime
, &inode
->i_atime
) >= 0)
1625 * Is ctime younger than atime? If yes, update atime:
1627 if (timespec_compare(&inode
->i_ctime
, &inode
->i_atime
) >= 0)
1631 * Is the previous atime value older than a day? If yes,
1634 if ((long)(now
.tv_sec
- inode
->i_atime
.tv_sec
) >= 24*60*60)
1637 * Good, we can skip the atime update:
1642 int generic_update_time(struct inode
*inode
, struct timespec
*time
, int flags
)
1644 int iflags
= I_DIRTY_TIME
;
1646 if (flags
& S_ATIME
)
1647 inode
->i_atime
= *time
;
1648 if (flags
& S_VERSION
)
1649 inode_inc_iversion(inode
);
1650 if (flags
& S_CTIME
)
1651 inode
->i_ctime
= *time
;
1652 if (flags
& S_MTIME
)
1653 inode
->i_mtime
= *time
;
1655 if (!(inode
->i_sb
->s_flags
& SB_LAZYTIME
) || (flags
& S_VERSION
))
1656 iflags
|= I_DIRTY_SYNC
;
1657 __mark_inode_dirty(inode
, iflags
);
1660 EXPORT_SYMBOL(generic_update_time
);
1663 * This does the actual work of updating an inodes time or version. Must have
1664 * had called mnt_want_write() before calling this.
1666 int update_time(struct inode
*inode
, struct timespec
*time
, int flags
)
1668 int (*update_time
)(struct inode
*, struct timespec
*, int);
1670 update_time
= inode
->i_op
->update_time
? inode
->i_op
->update_time
:
1671 generic_update_time
;
1673 return update_time(inode
, time
, flags
);
1675 EXPORT_SYMBOL_GPL(update_time
);
1678 * touch_atime - update the access time
1679 * @path: the &struct path to update
1680 * @inode: inode to update
1682 * Update the accessed time on an inode and mark it for writeback.
1683 * This function automatically handles read only file systems and media,
1684 * as well as the "noatime" flag and inode specific "noatime" markers.
1686 bool __atime_needs_update(const struct path
*path
, struct inode
*inode
,
1689 struct vfsmount
*mnt
= path
->mnt
;
1690 struct timespec now
;
1692 if (inode
->i_flags
& S_NOATIME
)
1695 /* Atime updates will likely cause i_uid and i_gid to be written
1696 * back improprely if their true value is unknown to the vfs.
1698 if (HAS_UNMAPPED_ID(inode
))
1701 if (IS_NOATIME(inode
))
1703 if ((inode
->i_sb
->s_flags
& SB_NODIRATIME
) && S_ISDIR(inode
->i_mode
))
1706 if (mnt
->mnt_flags
& MNT_NOATIME
)
1708 if ((mnt
->mnt_flags
& MNT_NODIRATIME
) && S_ISDIR(inode
->i_mode
))
1711 now
= current_time(inode
);
1713 if (!relatime_need_update(path
, inode
, now
, rcu
))
1716 if (timespec_equal(&inode
->i_atime
, &now
))
1722 void touch_atime(const struct path
*path
)
1724 struct vfsmount
*mnt
= path
->mnt
;
1725 struct inode
*inode
= d_inode(path
->dentry
);
1726 struct timespec now
;
1728 if (!__atime_needs_update(path
, inode
, false))
1731 if (!sb_start_write_trylock(inode
->i_sb
))
1734 if (__mnt_want_write(mnt
) != 0)
1737 * File systems can error out when updating inodes if they need to
1738 * allocate new space to modify an inode (such is the case for
1739 * Btrfs), but since we touch atime while walking down the path we
1740 * really don't care if we failed to update the atime of the file,
1741 * so just ignore the return value.
1742 * We may also fail on filesystems that have the ability to make parts
1743 * of the fs read only, e.g. subvolumes in Btrfs.
1745 now
= current_time(inode
);
1746 update_time(inode
, &now
, S_ATIME
);
1747 __mnt_drop_write(mnt
);
1749 sb_end_write(inode
->i_sb
);
1751 EXPORT_SYMBOL(touch_atime
);
1754 * The logic we want is
1756 * if suid or (sgid and xgrp)
1759 int should_remove_suid(struct dentry
*dentry
)
1761 struct inode
*inode
= d_inode(dentry
);
1762 umode_t mode
= inode
->i_mode
;
1765 /* suid always must be killed */
1766 if (unlikely(mode
& S_ISUID
))
1767 kill
= ATTR_KILL_SUID
;
1770 * sgid without any exec bits is just a mandatory locking mark; leave
1771 * it alone. If some exec bits are set, it's a real sgid; kill it.
1773 if (unlikely((mode
& S_ISGID
) && (mode
& S_IXGRP
)))
1774 kill
|= ATTR_KILL_SGID
;
1776 if (unlikely(kill
&& !capable_wrt_inode_uidgid(inode
, CAP_FSETID
) &&
1782 EXPORT_SYMBOL(should_remove_suid
);
1785 * Return mask of changes for notify_change() that need to be done as a
1786 * response to write or truncate. Return 0 if nothing has to be changed.
1787 * Negative value on error (change should be denied).
1789 int dentry_needs_remove_privs(struct dentry
*dentry
)
1791 struct inode
*inode
= d_inode(dentry
);
1795 if (IS_NOSEC(inode
))
1798 mask
= should_remove_suid(dentry
);
1799 ret
= security_inode_need_killpriv(dentry
);
1803 mask
|= ATTR_KILL_PRIV
;
1807 static int __remove_privs(struct dentry
*dentry
, int kill
)
1809 struct iattr newattrs
;
1811 newattrs
.ia_valid
= ATTR_FORCE
| kill
;
1813 * Note we call this on write, so notify_change will not
1814 * encounter any conflicting delegations:
1816 return notify_change(dentry
, &newattrs
, NULL
);
1820 * Remove special file priviledges (suid, capabilities) when file is written
1823 int file_remove_privs(struct file
*file
)
1825 struct dentry
*dentry
= file_dentry(file
);
1826 struct inode
*inode
= file_inode(file
);
1831 * Fast path for nothing security related.
1832 * As well for non-regular files, e.g. blkdev inodes.
1833 * For example, blkdev_write_iter() might get here
1834 * trying to remove privs which it is not allowed to.
1836 if (IS_NOSEC(inode
) || !S_ISREG(inode
->i_mode
))
1839 kill
= dentry_needs_remove_privs(dentry
);
1843 error
= __remove_privs(dentry
, kill
);
1845 inode_has_no_xattr(inode
);
1849 EXPORT_SYMBOL(file_remove_privs
);
1852 * file_update_time - update mtime and ctime time
1853 * @file: file accessed
1855 * Update the mtime and ctime members of an inode and mark the inode
1856 * for writeback. Note that this function is meant exclusively for
1857 * usage in the file write path of filesystems, and filesystems may
1858 * choose to explicitly ignore update via this function with the
1859 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1860 * timestamps are handled by the server. This can return an error for
1861 * file systems who need to allocate space in order to update an inode.
1864 int file_update_time(struct file
*file
)
1866 struct inode
*inode
= file_inode(file
);
1867 struct timespec now
;
1871 /* First try to exhaust all avenues to not sync */
1872 if (IS_NOCMTIME(inode
))
1875 now
= current_time(inode
);
1876 if (!timespec_equal(&inode
->i_mtime
, &now
))
1879 if (!timespec_equal(&inode
->i_ctime
, &now
))
1882 if (IS_I_VERSION(inode
))
1883 sync_it
|= S_VERSION
;
1888 /* Finally allowed to write? Takes lock. */
1889 if (__mnt_want_write_file(file
))
1892 ret
= update_time(inode
, &now
, sync_it
);
1893 __mnt_drop_write_file(file
);
1897 EXPORT_SYMBOL(file_update_time
);
1899 int inode_needs_sync(struct inode
*inode
)
1903 if (S_ISDIR(inode
->i_mode
) && IS_DIRSYNC(inode
))
1907 EXPORT_SYMBOL(inode_needs_sync
);
1910 * If we try to find an inode in the inode hash while it is being
1911 * deleted, we have to wait until the filesystem completes its
1912 * deletion before reporting that it isn't found. This function waits
1913 * until the deletion _might_ have completed. Callers are responsible
1914 * to recheck inode state.
1916 * It doesn't matter if I_NEW is not set initially, a call to
1917 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1920 static void __wait_on_freeing_inode(struct inode
*inode
)
1922 wait_queue_head_t
*wq
;
1923 DEFINE_WAIT_BIT(wait
, &inode
->i_state
, __I_NEW
);
1924 wq
= bit_waitqueue(&inode
->i_state
, __I_NEW
);
1925 prepare_to_wait(wq
, &wait
.wq_entry
, TASK_UNINTERRUPTIBLE
);
1926 spin_unlock(&inode
->i_lock
);
1927 spin_unlock(&inode_hash_lock
);
1929 finish_wait(wq
, &wait
.wq_entry
);
1930 spin_lock(&inode_hash_lock
);
1933 static __initdata
unsigned long ihash_entries
;
1934 static int __init
set_ihash_entries(char *str
)
1938 ihash_entries
= simple_strtoul(str
, &str
, 0);
1941 __setup("ihash_entries=", set_ihash_entries
);
1944 * Initialize the waitqueues and inode hash table.
1946 void __init
inode_init_early(void)
1948 /* If hashes are distributed across NUMA nodes, defer
1949 * hash allocation until vmalloc space is available.
1955 alloc_large_system_hash("Inode-cache",
1956 sizeof(struct hlist_head
),
1959 HASH_EARLY
| HASH_ZERO
,
1966 void __init
inode_init(void)
1968 /* inode slab cache */
1969 inode_cachep
= kmem_cache_create("inode_cache",
1970 sizeof(struct inode
),
1972 (SLAB_RECLAIM_ACCOUNT
|SLAB_PANIC
|
1973 SLAB_MEM_SPREAD
|SLAB_ACCOUNT
),
1976 /* Hash may have been set up in inode_init_early */
1981 alloc_large_system_hash("Inode-cache",
1982 sizeof(struct hlist_head
),
1992 void init_special_inode(struct inode
*inode
, umode_t mode
, dev_t rdev
)
1994 inode
->i_mode
= mode
;
1995 if (S_ISCHR(mode
)) {
1996 inode
->i_fop
= &def_chr_fops
;
1997 inode
->i_rdev
= rdev
;
1998 } else if (S_ISBLK(mode
)) {
1999 inode
->i_fop
= &def_blk_fops
;
2000 inode
->i_rdev
= rdev
;
2001 } else if (S_ISFIFO(mode
))
2002 inode
->i_fop
= &pipefifo_fops
;
2003 else if (S_ISSOCK(mode
))
2004 ; /* leave it no_open_fops */
2006 printk(KERN_DEBUG
"init_special_inode: bogus i_mode (%o) for"
2007 " inode %s:%lu\n", mode
, inode
->i_sb
->s_id
,
2010 EXPORT_SYMBOL(init_special_inode
);
2013 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
2015 * @dir: Directory inode
2016 * @mode: mode of the new inode
2018 void inode_init_owner(struct inode
*inode
, const struct inode
*dir
,
2021 inode
->i_uid
= current_fsuid();
2022 if (dir
&& dir
->i_mode
& S_ISGID
) {
2023 inode
->i_gid
= dir
->i_gid
;
2025 /* Directories are special, and always inherit S_ISGID */
2028 else if ((mode
& (S_ISGID
| S_IXGRP
)) == (S_ISGID
| S_IXGRP
) &&
2029 !in_group_p(inode
->i_gid
) &&
2030 !capable_wrt_inode_uidgid(dir
, CAP_FSETID
))
2033 inode
->i_gid
= current_fsgid();
2034 inode
->i_mode
= mode
;
2036 EXPORT_SYMBOL(inode_init_owner
);
2039 * inode_owner_or_capable - check current task permissions to inode
2040 * @inode: inode being checked
2042 * Return true if current either has CAP_FOWNER in a namespace with the
2043 * inode owner uid mapped, or owns the file.
2045 bool inode_owner_or_capable(const struct inode
*inode
)
2047 struct user_namespace
*ns
;
2049 if (uid_eq(current_fsuid(), inode
->i_uid
))
2052 ns
= current_user_ns();
2053 if (kuid_has_mapping(ns
, inode
->i_uid
) && ns_capable(ns
, CAP_FOWNER
))
2057 EXPORT_SYMBOL(inode_owner_or_capable
);
2060 * Direct i/o helper functions
2062 static void __inode_dio_wait(struct inode
*inode
)
2064 wait_queue_head_t
*wq
= bit_waitqueue(&inode
->i_state
, __I_DIO_WAKEUP
);
2065 DEFINE_WAIT_BIT(q
, &inode
->i_state
, __I_DIO_WAKEUP
);
2068 prepare_to_wait(wq
, &q
.wq_entry
, TASK_UNINTERRUPTIBLE
);
2069 if (atomic_read(&inode
->i_dio_count
))
2071 } while (atomic_read(&inode
->i_dio_count
));
2072 finish_wait(wq
, &q
.wq_entry
);
2076 * inode_dio_wait - wait for outstanding DIO requests to finish
2077 * @inode: inode to wait for
2079 * Waits for all pending direct I/O requests to finish so that we can
2080 * proceed with a truncate or equivalent operation.
2082 * Must be called under a lock that serializes taking new references
2083 * to i_dio_count, usually by inode->i_mutex.
2085 void inode_dio_wait(struct inode
*inode
)
2087 if (atomic_read(&inode
->i_dio_count
))
2088 __inode_dio_wait(inode
);
2090 EXPORT_SYMBOL(inode_dio_wait
);
2093 * inode_set_flags - atomically set some inode flags
2095 * Note: the caller should be holding i_mutex, or else be sure that
2096 * they have exclusive access to the inode structure (i.e., while the
2097 * inode is being instantiated). The reason for the cmpxchg() loop
2098 * --- which wouldn't be necessary if all code paths which modify
2099 * i_flags actually followed this rule, is that there is at least one
2100 * code path which doesn't today so we use cmpxchg() out of an abundance
2103 * In the long run, i_mutex is overkill, and we should probably look
2104 * at using the i_lock spinlock to protect i_flags, and then make sure
2105 * it is so documented in include/linux/fs.h and that all code follows
2106 * the locking convention!!
2108 void inode_set_flags(struct inode
*inode
, unsigned int flags
,
2111 unsigned int old_flags
, new_flags
;
2113 WARN_ON_ONCE(flags
& ~mask
);
2115 old_flags
= READ_ONCE(inode
->i_flags
);
2116 new_flags
= (old_flags
& ~mask
) | flags
;
2117 } while (unlikely(cmpxchg(&inode
->i_flags
, old_flags
,
2118 new_flags
) != old_flags
));
2120 EXPORT_SYMBOL(inode_set_flags
);
2122 void inode_nohighmem(struct inode
*inode
)
2124 mapping_set_gfp_mask(inode
->i_mapping
, GFP_USER
);
2126 EXPORT_SYMBOL(inode_nohighmem
);
2129 * current_time - Return FS time
2132 * Return the current time truncated to the time granularity supported by
2135 * Note that inode and inode->sb cannot be NULL.
2136 * Otherwise, the function warns and returns time without truncation.
2138 struct timespec
current_time(struct inode
*inode
)
2140 struct timespec now
= current_kernel_time();
2142 if (unlikely(!inode
->i_sb
)) {
2143 WARN(1, "current_time() called with uninitialized super_block in the inode");
2147 return timespec_trunc(now
, inode
->i_sb
->s_time_gran
);
2149 EXPORT_SYMBOL(current_time
);