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_sb_list_lock protects:
32 * 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_wb_list
35 * inode_hash_lock protects:
36 * inode_hashtable, inode->i_hash
42 * Inode LRU list locks
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
);
60 __cacheline_aligned_in_smp
DEFINE_SPINLOCK(inode_sb_list_lock
);
63 * Empty aops. Can be used for the cases where the user does not
64 * define any of the address_space operations.
66 const struct address_space_operations empty_aops
= {
68 EXPORT_SYMBOL(empty_aops
);
71 * Statistics gathering..
73 struct inodes_stat_t inodes_stat
;
75 static DEFINE_PER_CPU(unsigned long, nr_inodes
);
76 static DEFINE_PER_CPU(unsigned long, nr_unused
);
78 static struct kmem_cache
*inode_cachep __read_mostly
;
80 static long get_nr_inodes(void)
84 for_each_possible_cpu(i
)
85 sum
+= per_cpu(nr_inodes
, i
);
86 return sum
< 0 ? 0 : sum
;
89 static inline long get_nr_inodes_unused(void)
93 for_each_possible_cpu(i
)
94 sum
+= per_cpu(nr_unused
, i
);
95 return sum
< 0 ? 0 : sum
;
98 long get_nr_dirty_inodes(void)
100 /* not actually dirty inodes, but a wild approximation */
101 long nr_dirty
= get_nr_inodes() - get_nr_inodes_unused();
102 return nr_dirty
> 0 ? nr_dirty
: 0;
106 * Handle nr_inode sysctl
109 int proc_nr_inodes(struct ctl_table
*table
, int write
,
110 void __user
*buffer
, size_t *lenp
, loff_t
*ppos
)
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
);
118 static int no_open(struct inode
*inode
, struct file
*file
)
124 * inode_init_always - perform inode structure intialisation
125 * @sb: superblock inode belongs to
126 * @inode: inode to initialise
128 * These are initializations that need to be done on every inode
129 * allocation as the fields are not initialised by slab allocation.
131 int inode_init_always(struct super_block
*sb
, struct inode
*inode
)
133 static const struct inode_operations empty_iops
;
134 static const struct file_operations no_open_fops
= {.open
= no_open
};
135 struct address_space
*const mapping
= &inode
->i_data
;
138 inode
->i_blkbits
= sb
->s_blocksize_bits
;
140 atomic_set(&inode
->i_count
, 1);
141 inode
->i_op
= &empty_iops
;
142 inode
->i_fop
= &no_open_fops
;
143 inode
->__i_nlink
= 1;
144 inode
->i_opflags
= 0;
145 i_uid_write(inode
, 0);
146 i_gid_write(inode
, 0);
147 atomic_set(&inode
->i_writecount
, 0);
151 inode
->i_generation
= 0;
152 inode
->i_pipe
= NULL
;
153 inode
->i_bdev
= NULL
;
154 inode
->i_cdev
= NULL
;
155 inode
->i_link
= NULL
;
157 inode
->dirtied_when
= 0;
159 if (security_inode_alloc(inode
))
161 spin_lock_init(&inode
->i_lock
);
162 lockdep_set_class(&inode
->i_lock
, &sb
->s_type
->i_lock_key
);
164 mutex_init(&inode
->i_mutex
);
165 lockdep_set_class(&inode
->i_mutex
, &sb
->s_type
->i_mutex_key
);
167 atomic_set(&inode
->i_dio_count
, 0);
169 mapping
->a_ops
= &empty_aops
;
170 mapping
->host
= inode
;
172 atomic_set(&mapping
->i_mmap_writable
, 0);
173 mapping_set_gfp_mask(mapping
, GFP_HIGHUSER_MOVABLE
);
174 mapping
->private_data
= NULL
;
175 mapping
->writeback_index
= 0;
176 inode
->i_private
= NULL
;
177 inode
->i_mapping
= mapping
;
178 INIT_HLIST_HEAD(&inode
->i_dentry
); /* buggered by rcu freeing */
179 #ifdef CONFIG_FS_POSIX_ACL
180 inode
->i_acl
= inode
->i_default_acl
= ACL_NOT_CACHED
;
183 #ifdef CONFIG_FSNOTIFY
184 inode
->i_fsnotify_mask
= 0;
186 inode
->i_flctx
= NULL
;
187 this_cpu_inc(nr_inodes
);
193 EXPORT_SYMBOL(inode_init_always
);
195 static struct inode
*alloc_inode(struct super_block
*sb
)
199 if (sb
->s_op
->alloc_inode
)
200 inode
= sb
->s_op
->alloc_inode(sb
);
202 inode
= kmem_cache_alloc(inode_cachep
, GFP_KERNEL
);
207 if (unlikely(inode_init_always(sb
, inode
))) {
208 if (inode
->i_sb
->s_op
->destroy_inode
)
209 inode
->i_sb
->s_op
->destroy_inode(inode
);
211 kmem_cache_free(inode_cachep
, inode
);
218 void free_inode_nonrcu(struct inode
*inode
)
220 kmem_cache_free(inode_cachep
, inode
);
222 EXPORT_SYMBOL(free_inode_nonrcu
);
224 void __destroy_inode(struct inode
*inode
)
226 BUG_ON(inode_has_buffers(inode
));
227 security_inode_free(inode
);
228 fsnotify_inode_delete(inode
);
229 locks_free_lock_context(inode
->i_flctx
);
230 if (!inode
->i_nlink
) {
231 WARN_ON(atomic_long_read(&inode
->i_sb
->s_remove_count
) == 0);
232 atomic_long_dec(&inode
->i_sb
->s_remove_count
);
235 #ifdef CONFIG_FS_POSIX_ACL
236 if (inode
->i_acl
&& inode
->i_acl
!= ACL_NOT_CACHED
)
237 posix_acl_release(inode
->i_acl
);
238 if (inode
->i_default_acl
&& inode
->i_default_acl
!= ACL_NOT_CACHED
)
239 posix_acl_release(inode
->i_default_acl
);
241 this_cpu_dec(nr_inodes
);
243 EXPORT_SYMBOL(__destroy_inode
);
245 static void i_callback(struct rcu_head
*head
)
247 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
248 kmem_cache_free(inode_cachep
, inode
);
251 static void destroy_inode(struct inode
*inode
)
253 BUG_ON(!list_empty(&inode
->i_lru
));
254 __destroy_inode(inode
);
255 if (inode
->i_sb
->s_op
->destroy_inode
)
256 inode
->i_sb
->s_op
->destroy_inode(inode
);
258 call_rcu(&inode
->i_rcu
, i_callback
);
262 * drop_nlink - directly drop an inode's link count
265 * This is a low-level filesystem helper to replace any
266 * direct filesystem manipulation of i_nlink. In cases
267 * where we are attempting to track writes to the
268 * filesystem, a decrement to zero means an imminent
269 * write when the file is truncated and actually unlinked
272 void drop_nlink(struct inode
*inode
)
274 WARN_ON(inode
->i_nlink
== 0);
277 atomic_long_inc(&inode
->i_sb
->s_remove_count
);
279 EXPORT_SYMBOL(drop_nlink
);
282 * clear_nlink - directly zero an inode's link count
285 * This is a low-level filesystem helper to replace any
286 * direct filesystem manipulation of i_nlink. See
287 * drop_nlink() for why we care about i_nlink hitting zero.
289 void clear_nlink(struct inode
*inode
)
291 if (inode
->i_nlink
) {
292 inode
->__i_nlink
= 0;
293 atomic_long_inc(&inode
->i_sb
->s_remove_count
);
296 EXPORT_SYMBOL(clear_nlink
);
299 * set_nlink - directly set an inode's link count
301 * @nlink: new nlink (should be non-zero)
303 * This is a low-level filesystem helper to replace any
304 * direct filesystem manipulation of i_nlink.
306 void set_nlink(struct inode
*inode
, unsigned int nlink
)
311 /* Yes, some filesystems do change nlink from zero to one */
312 if (inode
->i_nlink
== 0)
313 atomic_long_dec(&inode
->i_sb
->s_remove_count
);
315 inode
->__i_nlink
= nlink
;
318 EXPORT_SYMBOL(set_nlink
);
321 * inc_nlink - directly increment an inode's link count
324 * This is a low-level filesystem helper to replace any
325 * direct filesystem manipulation of i_nlink. Currently,
326 * it is only here for parity with dec_nlink().
328 void inc_nlink(struct inode
*inode
)
330 if (unlikely(inode
->i_nlink
== 0)) {
331 WARN_ON(!(inode
->i_state
& I_LINKABLE
));
332 atomic_long_dec(&inode
->i_sb
->s_remove_count
);
337 EXPORT_SYMBOL(inc_nlink
);
339 void address_space_init_once(struct address_space
*mapping
)
341 memset(mapping
, 0, sizeof(*mapping
));
342 INIT_RADIX_TREE(&mapping
->page_tree
, GFP_ATOMIC
);
343 spin_lock_init(&mapping
->tree_lock
);
344 init_rwsem(&mapping
->i_mmap_rwsem
);
345 INIT_LIST_HEAD(&mapping
->private_list
);
346 spin_lock_init(&mapping
->private_lock
);
347 mapping
->i_mmap
= RB_ROOT
;
349 EXPORT_SYMBOL(address_space_init_once
);
352 * These are initializations that only need to be done
353 * once, because the fields are idempotent across use
354 * of the inode, so let the slab aware of that.
356 void inode_init_once(struct inode
*inode
)
358 memset(inode
, 0, sizeof(*inode
));
359 INIT_HLIST_NODE(&inode
->i_hash
);
360 INIT_LIST_HEAD(&inode
->i_devices
);
361 INIT_LIST_HEAD(&inode
->i_wb_list
);
362 INIT_LIST_HEAD(&inode
->i_lru
);
363 address_space_init_once(&inode
->i_data
);
364 i_size_ordered_init(inode
);
365 #ifdef CONFIG_FSNOTIFY
366 INIT_HLIST_HEAD(&inode
->i_fsnotify_marks
);
369 EXPORT_SYMBOL(inode_init_once
);
371 static void init_once(void *foo
)
373 struct inode
*inode
= (struct inode
*) foo
;
375 inode_init_once(inode
);
379 * inode->i_lock must be held
381 void __iget(struct inode
*inode
)
383 atomic_inc(&inode
->i_count
);
387 * get additional reference to inode; caller must already hold one.
389 void ihold(struct inode
*inode
)
391 WARN_ON(atomic_inc_return(&inode
->i_count
) < 2);
393 EXPORT_SYMBOL(ihold
);
395 static void inode_lru_list_add(struct inode
*inode
)
397 if (list_lru_add(&inode
->i_sb
->s_inode_lru
, &inode
->i_lru
))
398 this_cpu_inc(nr_unused
);
402 * Add inode to LRU if needed (inode is unused and clean).
404 * Needs inode->i_lock held.
406 void inode_add_lru(struct inode
*inode
)
408 if (!(inode
->i_state
& (I_DIRTY_ALL
| I_SYNC
|
409 I_FREEING
| I_WILL_FREE
)) &&
410 !atomic_read(&inode
->i_count
) && inode
->i_sb
->s_flags
& MS_ACTIVE
)
411 inode_lru_list_add(inode
);
415 static void inode_lru_list_del(struct inode
*inode
)
418 if (list_lru_del(&inode
->i_sb
->s_inode_lru
, &inode
->i_lru
))
419 this_cpu_dec(nr_unused
);
423 * inode_sb_list_add - add inode to the superblock list of inodes
424 * @inode: inode to add
426 void inode_sb_list_add(struct inode
*inode
)
428 spin_lock(&inode_sb_list_lock
);
429 list_add(&inode
->i_sb_list
, &inode
->i_sb
->s_inodes
);
430 spin_unlock(&inode_sb_list_lock
);
432 EXPORT_SYMBOL_GPL(inode_sb_list_add
);
434 static inline void inode_sb_list_del(struct inode
*inode
)
436 if (!list_empty(&inode
->i_sb_list
)) {
437 spin_lock(&inode_sb_list_lock
);
438 list_del_init(&inode
->i_sb_list
);
439 spin_unlock(&inode_sb_list_lock
);
443 static unsigned long hash(struct super_block
*sb
, unsigned long hashval
)
447 tmp
= (hashval
* (unsigned long)sb
) ^ (GOLDEN_RATIO_PRIME
+ hashval
) /
449 tmp
= tmp
^ ((tmp
^ GOLDEN_RATIO_PRIME
) >> i_hash_shift
);
450 return tmp
& i_hash_mask
;
454 * __insert_inode_hash - hash an inode
455 * @inode: unhashed inode
456 * @hashval: unsigned long value used to locate this object in the
459 * Add an inode to the inode hash for this superblock.
461 void __insert_inode_hash(struct inode
*inode
, unsigned long hashval
)
463 struct hlist_head
*b
= inode_hashtable
+ hash(inode
->i_sb
, hashval
);
465 spin_lock(&inode_hash_lock
);
466 spin_lock(&inode
->i_lock
);
467 hlist_add_head(&inode
->i_hash
, b
);
468 spin_unlock(&inode
->i_lock
);
469 spin_unlock(&inode_hash_lock
);
471 EXPORT_SYMBOL(__insert_inode_hash
);
474 * __remove_inode_hash - remove an inode from the hash
475 * @inode: inode to unhash
477 * Remove an inode from the superblock.
479 void __remove_inode_hash(struct inode
*inode
)
481 spin_lock(&inode_hash_lock
);
482 spin_lock(&inode
->i_lock
);
483 hlist_del_init(&inode
->i_hash
);
484 spin_unlock(&inode
->i_lock
);
485 spin_unlock(&inode_hash_lock
);
487 EXPORT_SYMBOL(__remove_inode_hash
);
489 void clear_inode(struct inode
*inode
)
493 * We have to cycle tree_lock here because reclaim can be still in the
494 * process of removing the last page (in __delete_from_page_cache())
495 * and we must not free mapping under it.
497 spin_lock_irq(&inode
->i_data
.tree_lock
);
498 BUG_ON(inode
->i_data
.nrpages
);
499 BUG_ON(inode
->i_data
.nrshadows
);
500 spin_unlock_irq(&inode
->i_data
.tree_lock
);
501 BUG_ON(!list_empty(&inode
->i_data
.private_list
));
502 BUG_ON(!(inode
->i_state
& I_FREEING
));
503 BUG_ON(inode
->i_state
& I_CLEAR
);
504 /* don't need i_lock here, no concurrent mods to i_state */
505 inode
->i_state
= I_FREEING
| I_CLEAR
;
507 EXPORT_SYMBOL(clear_inode
);
510 * Free the inode passed in, removing it from the lists it is still connected
511 * to. We remove any pages still attached to the inode and wait for any IO that
512 * is still in progress before finally destroying the inode.
514 * An inode must already be marked I_FREEING so that we avoid the inode being
515 * moved back onto lists if we race with other code that manipulates the lists
516 * (e.g. writeback_single_inode). The caller is responsible for setting this.
518 * An inode must already be removed from the LRU list before being evicted from
519 * the cache. This should occur atomically with setting the I_FREEING state
520 * flag, so no inodes here should ever be on the LRU when being evicted.
522 static void evict(struct inode
*inode
)
524 const struct super_operations
*op
= inode
->i_sb
->s_op
;
526 BUG_ON(!(inode
->i_state
& I_FREEING
));
527 BUG_ON(!list_empty(&inode
->i_lru
));
529 if (!list_empty(&inode
->i_wb_list
))
530 inode_wb_list_del(inode
);
532 inode_sb_list_del(inode
);
535 * Wait for flusher thread to be done with the inode so that filesystem
536 * does not start destroying it while writeback is still running. Since
537 * the inode has I_FREEING set, flusher thread won't start new work on
538 * the inode. We just have to wait for running writeback to finish.
540 inode_wait_for_writeback(inode
);
542 if (op
->evict_inode
) {
543 op
->evict_inode(inode
);
545 truncate_inode_pages_final(&inode
->i_data
);
548 if (S_ISBLK(inode
->i_mode
) && inode
->i_bdev
)
550 if (S_ISCHR(inode
->i_mode
) && inode
->i_cdev
)
553 remove_inode_hash(inode
);
555 spin_lock(&inode
->i_lock
);
556 wake_up_bit(&inode
->i_state
, __I_NEW
);
557 BUG_ON(inode
->i_state
!= (I_FREEING
| I_CLEAR
));
558 spin_unlock(&inode
->i_lock
);
560 destroy_inode(inode
);
564 * dispose_list - dispose of the contents of a local list
565 * @head: the head of the list to free
567 * Dispose-list gets a local list with local inodes in it, so it doesn't
568 * need to worry about list corruption and SMP locks.
570 static void dispose_list(struct list_head
*head
)
572 while (!list_empty(head
)) {
575 inode
= list_first_entry(head
, struct inode
, i_lru
);
576 list_del_init(&inode
->i_lru
);
583 * evict_inodes - evict all evictable inodes for a superblock
584 * @sb: superblock to operate on
586 * Make sure that no inodes with zero refcount are retained. This is
587 * called by superblock shutdown after having MS_ACTIVE flag removed,
588 * so any inode reaching zero refcount during or after that call will
589 * be immediately evicted.
591 void evict_inodes(struct super_block
*sb
)
593 struct inode
*inode
, *next
;
596 spin_lock(&inode_sb_list_lock
);
597 list_for_each_entry_safe(inode
, next
, &sb
->s_inodes
, i_sb_list
) {
598 if (atomic_read(&inode
->i_count
))
601 spin_lock(&inode
->i_lock
);
602 if (inode
->i_state
& (I_NEW
| I_FREEING
| I_WILL_FREE
)) {
603 spin_unlock(&inode
->i_lock
);
607 inode
->i_state
|= I_FREEING
;
608 inode_lru_list_del(inode
);
609 spin_unlock(&inode
->i_lock
);
610 list_add(&inode
->i_lru
, &dispose
);
612 spin_unlock(&inode_sb_list_lock
);
614 dispose_list(&dispose
);
618 * invalidate_inodes - attempt to free all inodes on a superblock
619 * @sb: superblock to operate on
620 * @kill_dirty: flag to guide handling of dirty inodes
622 * Attempts to free all inodes for a given superblock. If there were any
623 * busy inodes return a non-zero value, else zero.
624 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
627 int invalidate_inodes(struct super_block
*sb
, bool kill_dirty
)
630 struct inode
*inode
, *next
;
633 spin_lock(&inode_sb_list_lock
);
634 list_for_each_entry_safe(inode
, next
, &sb
->s_inodes
, i_sb_list
) {
635 spin_lock(&inode
->i_lock
);
636 if (inode
->i_state
& (I_NEW
| I_FREEING
| I_WILL_FREE
)) {
637 spin_unlock(&inode
->i_lock
);
640 if (inode
->i_state
& I_DIRTY_ALL
&& !kill_dirty
) {
641 spin_unlock(&inode
->i_lock
);
645 if (atomic_read(&inode
->i_count
)) {
646 spin_unlock(&inode
->i_lock
);
651 inode
->i_state
|= I_FREEING
;
652 inode_lru_list_del(inode
);
653 spin_unlock(&inode
->i_lock
);
654 list_add(&inode
->i_lru
, &dispose
);
656 spin_unlock(&inode_sb_list_lock
);
658 dispose_list(&dispose
);
664 * Isolate the inode from the LRU in preparation for freeing it.
666 * Any inodes which are pinned purely because of attached pagecache have their
667 * pagecache removed. If the inode has metadata buffers attached to
668 * mapping->private_list then try to remove them.
670 * If the inode has the I_REFERENCED flag set, then it means that it has been
671 * used recently - the flag is set in iput_final(). When we encounter such an
672 * inode, clear the flag and move it to the back of the LRU so it gets another
673 * pass through the LRU before it gets reclaimed. This is necessary because of
674 * the fact we are doing lazy LRU updates to minimise lock contention so the
675 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
676 * with this flag set because they are the inodes that are out of order.
678 static enum lru_status
inode_lru_isolate(struct list_head
*item
,
679 struct list_lru_one
*lru
, spinlock_t
*lru_lock
, void *arg
)
681 struct list_head
*freeable
= arg
;
682 struct inode
*inode
= container_of(item
, struct inode
, i_lru
);
685 * we are inverting the lru lock/inode->i_lock here, so use a trylock.
686 * If we fail to get the lock, just skip it.
688 if (!spin_trylock(&inode
->i_lock
))
692 * Referenced or dirty inodes are still in use. Give them another pass
693 * through the LRU as we canot reclaim them now.
695 if (atomic_read(&inode
->i_count
) ||
696 (inode
->i_state
& ~I_REFERENCED
)) {
697 list_lru_isolate(lru
, &inode
->i_lru
);
698 spin_unlock(&inode
->i_lock
);
699 this_cpu_dec(nr_unused
);
703 /* recently referenced inodes get one more pass */
704 if (inode
->i_state
& I_REFERENCED
) {
705 inode
->i_state
&= ~I_REFERENCED
;
706 spin_unlock(&inode
->i_lock
);
710 if (inode_has_buffers(inode
) || inode
->i_data
.nrpages
) {
712 spin_unlock(&inode
->i_lock
);
713 spin_unlock(lru_lock
);
714 if (remove_inode_buffers(inode
)) {
716 reap
= invalidate_mapping_pages(&inode
->i_data
, 0, -1);
717 if (current_is_kswapd())
718 __count_vm_events(KSWAPD_INODESTEAL
, reap
);
720 __count_vm_events(PGINODESTEAL
, reap
);
721 if (current
->reclaim_state
)
722 current
->reclaim_state
->reclaimed_slab
+= reap
;
729 WARN_ON(inode
->i_state
& I_NEW
);
730 inode
->i_state
|= I_FREEING
;
731 list_lru_isolate_move(lru
, &inode
->i_lru
, freeable
);
732 spin_unlock(&inode
->i_lock
);
734 this_cpu_dec(nr_unused
);
739 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
740 * This is called from the superblock shrinker function with a number of inodes
741 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
742 * then are freed outside inode_lock by dispose_list().
744 long prune_icache_sb(struct super_block
*sb
, struct shrink_control
*sc
)
749 freed
= list_lru_shrink_walk(&sb
->s_inode_lru
, sc
,
750 inode_lru_isolate
, &freeable
);
751 dispose_list(&freeable
);
755 static void __wait_on_freeing_inode(struct inode
*inode
);
757 * Called with the inode lock held.
759 static struct inode
*find_inode(struct super_block
*sb
,
760 struct hlist_head
*head
,
761 int (*test
)(struct inode
*, void *),
764 struct inode
*inode
= NULL
;
767 hlist_for_each_entry(inode
, head
, i_hash
) {
768 if (inode
->i_sb
!= sb
)
770 if (!test(inode
, data
))
772 spin_lock(&inode
->i_lock
);
773 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
774 __wait_on_freeing_inode(inode
);
778 spin_unlock(&inode
->i_lock
);
785 * find_inode_fast is the fast path version of find_inode, see the comment at
786 * iget_locked for details.
788 static struct inode
*find_inode_fast(struct super_block
*sb
,
789 struct hlist_head
*head
, unsigned long ino
)
791 struct inode
*inode
= NULL
;
794 hlist_for_each_entry(inode
, head
, i_hash
) {
795 if (inode
->i_ino
!= ino
)
797 if (inode
->i_sb
!= sb
)
799 spin_lock(&inode
->i_lock
);
800 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
801 __wait_on_freeing_inode(inode
);
805 spin_unlock(&inode
->i_lock
);
812 * Each cpu owns a range of LAST_INO_BATCH numbers.
813 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
814 * to renew the exhausted range.
816 * This does not significantly increase overflow rate because every CPU can
817 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
818 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
819 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
820 * overflow rate by 2x, which does not seem too significant.
822 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
823 * error if st_ino won't fit in target struct field. Use 32bit counter
824 * here to attempt to avoid that.
826 #define LAST_INO_BATCH 1024
827 static DEFINE_PER_CPU(unsigned int, last_ino
);
829 unsigned int get_next_ino(void)
831 unsigned int *p
= &get_cpu_var(last_ino
);
832 unsigned int res
= *p
;
835 if (unlikely((res
& (LAST_INO_BATCH
-1)) == 0)) {
836 static atomic_t shared_last_ino
;
837 int next
= atomic_add_return(LAST_INO_BATCH
, &shared_last_ino
);
839 res
= next
- LAST_INO_BATCH
;
844 put_cpu_var(last_ino
);
847 EXPORT_SYMBOL(get_next_ino
);
850 * new_inode_pseudo - obtain an inode
853 * Allocates a new inode for given superblock.
854 * Inode wont be chained in superblock s_inodes list
856 * - fs can't be unmount
857 * - quotas, fsnotify, writeback can't work
859 struct inode
*new_inode_pseudo(struct super_block
*sb
)
861 struct inode
*inode
= alloc_inode(sb
);
864 spin_lock(&inode
->i_lock
);
866 spin_unlock(&inode
->i_lock
);
867 INIT_LIST_HEAD(&inode
->i_sb_list
);
873 * new_inode - obtain an inode
876 * Allocates a new inode for given superblock. The default gfp_mask
877 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
878 * If HIGHMEM pages are unsuitable or it is known that pages allocated
879 * for the page cache are not reclaimable or migratable,
880 * mapping_set_gfp_mask() must be called with suitable flags on the
881 * newly created inode's mapping
884 struct inode
*new_inode(struct super_block
*sb
)
888 spin_lock_prefetch(&inode_sb_list_lock
);
890 inode
= new_inode_pseudo(sb
);
892 inode_sb_list_add(inode
);
895 EXPORT_SYMBOL(new_inode
);
897 #ifdef CONFIG_DEBUG_LOCK_ALLOC
898 void lockdep_annotate_inode_mutex_key(struct inode
*inode
)
900 if (S_ISDIR(inode
->i_mode
)) {
901 struct file_system_type
*type
= inode
->i_sb
->s_type
;
903 /* Set new key only if filesystem hasn't already changed it */
904 if (lockdep_match_class(&inode
->i_mutex
, &type
->i_mutex_key
)) {
906 * ensure nobody is actually holding i_mutex
908 mutex_destroy(&inode
->i_mutex
);
909 mutex_init(&inode
->i_mutex
);
910 lockdep_set_class(&inode
->i_mutex
,
911 &type
->i_mutex_dir_key
);
915 EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key
);
919 * unlock_new_inode - clear the I_NEW state and wake up any waiters
920 * @inode: new inode to unlock
922 * Called when the inode is fully initialised to clear the new state of the
923 * inode and wake up anyone waiting for the inode to finish initialisation.
925 void unlock_new_inode(struct inode
*inode
)
927 lockdep_annotate_inode_mutex_key(inode
);
928 spin_lock(&inode
->i_lock
);
929 WARN_ON(!(inode
->i_state
& I_NEW
));
930 inode
->i_state
&= ~I_NEW
;
932 wake_up_bit(&inode
->i_state
, __I_NEW
);
933 spin_unlock(&inode
->i_lock
);
935 EXPORT_SYMBOL(unlock_new_inode
);
938 * lock_two_nondirectories - take two i_mutexes on non-directory objects
940 * Lock any non-NULL argument that is not a directory.
941 * Zero, one or two objects may be locked by this function.
943 * @inode1: first inode to lock
944 * @inode2: second inode to lock
946 void lock_two_nondirectories(struct inode
*inode1
, struct inode
*inode2
)
949 swap(inode1
, inode2
);
951 if (inode1
&& !S_ISDIR(inode1
->i_mode
))
952 mutex_lock(&inode1
->i_mutex
);
953 if (inode2
&& !S_ISDIR(inode2
->i_mode
) && inode2
!= inode1
)
954 mutex_lock_nested(&inode2
->i_mutex
, I_MUTEX_NONDIR2
);
956 EXPORT_SYMBOL(lock_two_nondirectories
);
959 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
960 * @inode1: first inode to unlock
961 * @inode2: second inode to unlock
963 void unlock_two_nondirectories(struct inode
*inode1
, struct inode
*inode2
)
965 if (inode1
&& !S_ISDIR(inode1
->i_mode
))
966 mutex_unlock(&inode1
->i_mutex
);
967 if (inode2
&& !S_ISDIR(inode2
->i_mode
) && inode2
!= inode1
)
968 mutex_unlock(&inode2
->i_mutex
);
970 EXPORT_SYMBOL(unlock_two_nondirectories
);
973 * iget5_locked - obtain an inode from a mounted file system
974 * @sb: super block of file system
975 * @hashval: hash value (usually inode number) to get
976 * @test: callback used for comparisons between inodes
977 * @set: callback used to initialize a new struct inode
978 * @data: opaque data pointer to pass to @test and @set
980 * Search for the inode specified by @hashval and @data in the inode cache,
981 * and if present it is return it with an increased reference count. This is
982 * a generalized version of iget_locked() for file systems where the inode
983 * number is not sufficient for unique identification of an inode.
985 * If the inode is not in cache, allocate a new inode and return it locked,
986 * hashed, and with the I_NEW flag set. The file system gets to fill it in
987 * before unlocking it via unlock_new_inode().
989 * Note both @test and @set are called with the inode_hash_lock held, so can't
992 struct inode
*iget5_locked(struct super_block
*sb
, unsigned long hashval
,
993 int (*test
)(struct inode
*, void *),
994 int (*set
)(struct inode
*, void *), void *data
)
996 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
999 spin_lock(&inode_hash_lock
);
1000 inode
= find_inode(sb
, head
, test
, data
);
1001 spin_unlock(&inode_hash_lock
);
1004 wait_on_inode(inode
);
1008 inode
= alloc_inode(sb
);
1012 spin_lock(&inode_hash_lock
);
1013 /* We released the lock, so.. */
1014 old
= find_inode(sb
, head
, test
, data
);
1016 if (set(inode
, data
))
1019 spin_lock(&inode
->i_lock
);
1020 inode
->i_state
= I_NEW
;
1021 hlist_add_head(&inode
->i_hash
, head
);
1022 spin_unlock(&inode
->i_lock
);
1023 inode_sb_list_add(inode
);
1024 spin_unlock(&inode_hash_lock
);
1026 /* Return the locked inode with I_NEW set, the
1027 * caller is responsible for filling in the contents
1033 * Uhhuh, somebody else created the same inode under
1034 * us. Use the old inode instead of the one we just
1037 spin_unlock(&inode_hash_lock
);
1038 destroy_inode(inode
);
1040 wait_on_inode(inode
);
1045 spin_unlock(&inode_hash_lock
);
1046 destroy_inode(inode
);
1049 EXPORT_SYMBOL(iget5_locked
);
1052 * iget_locked - obtain an inode from a mounted file system
1053 * @sb: super block of file system
1054 * @ino: inode number to get
1056 * Search for the inode specified by @ino in the inode cache and if present
1057 * return it with an increased reference count. This is for file systems
1058 * where the inode number is sufficient for unique identification of an inode.
1060 * If the inode is not in cache, allocate a new inode and return it locked,
1061 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1062 * before unlocking it via unlock_new_inode().
1064 struct inode
*iget_locked(struct super_block
*sb
, unsigned long ino
)
1066 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1067 struct inode
*inode
;
1069 spin_lock(&inode_hash_lock
);
1070 inode
= find_inode_fast(sb
, head
, ino
);
1071 spin_unlock(&inode_hash_lock
);
1073 wait_on_inode(inode
);
1077 inode
= alloc_inode(sb
);
1081 spin_lock(&inode_hash_lock
);
1082 /* We released the lock, so.. */
1083 old
= find_inode_fast(sb
, head
, ino
);
1086 spin_lock(&inode
->i_lock
);
1087 inode
->i_state
= I_NEW
;
1088 hlist_add_head(&inode
->i_hash
, head
);
1089 spin_unlock(&inode
->i_lock
);
1090 inode_sb_list_add(inode
);
1091 spin_unlock(&inode_hash_lock
);
1093 /* Return the locked inode with I_NEW set, the
1094 * caller is responsible for filling in the contents
1100 * Uhhuh, somebody else created the same inode under
1101 * us. Use the old inode instead of the one we just
1104 spin_unlock(&inode_hash_lock
);
1105 destroy_inode(inode
);
1107 wait_on_inode(inode
);
1111 EXPORT_SYMBOL(iget_locked
);
1114 * search the inode cache for a matching inode number.
1115 * If we find one, then the inode number we are trying to
1116 * allocate is not unique and so we should not use it.
1118 * Returns 1 if the inode number is unique, 0 if it is not.
1120 static int test_inode_iunique(struct super_block
*sb
, unsigned long ino
)
1122 struct hlist_head
*b
= inode_hashtable
+ hash(sb
, ino
);
1123 struct inode
*inode
;
1125 spin_lock(&inode_hash_lock
);
1126 hlist_for_each_entry(inode
, b
, i_hash
) {
1127 if (inode
->i_ino
== ino
&& inode
->i_sb
== sb
) {
1128 spin_unlock(&inode_hash_lock
);
1132 spin_unlock(&inode_hash_lock
);
1138 * iunique - get a unique inode number
1140 * @max_reserved: highest reserved inode number
1142 * Obtain an inode number that is unique on the system for a given
1143 * superblock. This is used by file systems that have no natural
1144 * permanent inode numbering system. An inode number is returned that
1145 * is higher than the reserved limit but unique.
1148 * With a large number of inodes live on the file system this function
1149 * currently becomes quite slow.
1151 ino_t
iunique(struct super_block
*sb
, ino_t max_reserved
)
1154 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1155 * error if st_ino won't fit in target struct field. Use 32bit counter
1156 * here to attempt to avoid that.
1158 static DEFINE_SPINLOCK(iunique_lock
);
1159 static unsigned int counter
;
1162 spin_lock(&iunique_lock
);
1164 if (counter
<= max_reserved
)
1165 counter
= max_reserved
+ 1;
1167 } while (!test_inode_iunique(sb
, res
));
1168 spin_unlock(&iunique_lock
);
1172 EXPORT_SYMBOL(iunique
);
1174 struct inode
*igrab(struct inode
*inode
)
1176 spin_lock(&inode
->i_lock
);
1177 if (!(inode
->i_state
& (I_FREEING
|I_WILL_FREE
))) {
1179 spin_unlock(&inode
->i_lock
);
1181 spin_unlock(&inode
->i_lock
);
1183 * Handle the case where s_op->clear_inode is not been
1184 * called yet, and somebody is calling igrab
1185 * while the inode is getting freed.
1191 EXPORT_SYMBOL(igrab
);
1194 * ilookup5_nowait - search for an inode in the inode cache
1195 * @sb: super block of file system to search
1196 * @hashval: hash value (usually inode number) to search for
1197 * @test: callback used for comparisons between inodes
1198 * @data: opaque data pointer to pass to @test
1200 * Search for the inode specified by @hashval and @data in the inode cache.
1201 * If the inode is in the cache, the inode is returned with an incremented
1204 * Note: I_NEW is not waited upon so you have to be very careful what you do
1205 * with the returned inode. You probably should be using ilookup5() instead.
1207 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1209 struct inode
*ilookup5_nowait(struct super_block
*sb
, unsigned long hashval
,
1210 int (*test
)(struct inode
*, void *), void *data
)
1212 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1213 struct inode
*inode
;
1215 spin_lock(&inode_hash_lock
);
1216 inode
= find_inode(sb
, head
, test
, data
);
1217 spin_unlock(&inode_hash_lock
);
1221 EXPORT_SYMBOL(ilookup5_nowait
);
1224 * ilookup5 - search for an inode in the inode cache
1225 * @sb: super block of file system to search
1226 * @hashval: hash value (usually inode number) to search for
1227 * @test: callback used for comparisons between inodes
1228 * @data: opaque data pointer to pass to @test
1230 * Search for the inode specified by @hashval and @data in the inode cache,
1231 * and if the inode is in the cache, return the inode with an incremented
1232 * reference count. Waits on I_NEW before returning the inode.
1233 * returned with an incremented reference count.
1235 * This is a generalized version of ilookup() for file systems where the
1236 * inode number is not sufficient for unique identification of an inode.
1238 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1240 struct inode
*ilookup5(struct super_block
*sb
, unsigned long hashval
,
1241 int (*test
)(struct inode
*, void *), void *data
)
1243 struct inode
*inode
= ilookup5_nowait(sb
, hashval
, test
, data
);
1246 wait_on_inode(inode
);
1249 EXPORT_SYMBOL(ilookup5
);
1252 * ilookup - search for an inode in the inode cache
1253 * @sb: super block of file system to search
1254 * @ino: inode number to search for
1256 * Search for the inode @ino in the inode cache, and if the inode is in the
1257 * cache, the inode is returned with an incremented reference count.
1259 struct inode
*ilookup(struct super_block
*sb
, unsigned long ino
)
1261 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1262 struct inode
*inode
;
1264 spin_lock(&inode_hash_lock
);
1265 inode
= find_inode_fast(sb
, head
, ino
);
1266 spin_unlock(&inode_hash_lock
);
1269 wait_on_inode(inode
);
1272 EXPORT_SYMBOL(ilookup
);
1275 * find_inode_nowait - find an inode in the inode cache
1276 * @sb: super block of file system to search
1277 * @hashval: hash value (usually inode number) to search for
1278 * @match: callback used for comparisons between inodes
1279 * @data: opaque data pointer to pass to @match
1281 * Search for the inode specified by @hashval and @data in the inode
1282 * cache, where the helper function @match will return 0 if the inode
1283 * does not match, 1 if the inode does match, and -1 if the search
1284 * should be stopped. The @match function must be responsible for
1285 * taking the i_lock spin_lock and checking i_state for an inode being
1286 * freed or being initialized, and incrementing the reference count
1287 * before returning 1. It also must not sleep, since it is called with
1288 * the inode_hash_lock spinlock held.
1290 * This is a even more generalized version of ilookup5() when the
1291 * function must never block --- find_inode() can block in
1292 * __wait_on_freeing_inode() --- or when the caller can not increment
1293 * the reference count because the resulting iput() might cause an
1294 * inode eviction. The tradeoff is that the @match funtion must be
1295 * very carefully implemented.
1297 struct inode
*find_inode_nowait(struct super_block
*sb
,
1298 unsigned long hashval
,
1299 int (*match
)(struct inode
*, unsigned long,
1303 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1304 struct inode
*inode
, *ret_inode
= NULL
;
1307 spin_lock(&inode_hash_lock
);
1308 hlist_for_each_entry(inode
, head
, i_hash
) {
1309 if (inode
->i_sb
!= sb
)
1311 mval
= match(inode
, hashval
, data
);
1319 spin_unlock(&inode_hash_lock
);
1322 EXPORT_SYMBOL(find_inode_nowait
);
1324 int insert_inode_locked(struct inode
*inode
)
1326 struct super_block
*sb
= inode
->i_sb
;
1327 ino_t ino
= inode
->i_ino
;
1328 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1331 struct inode
*old
= NULL
;
1332 spin_lock(&inode_hash_lock
);
1333 hlist_for_each_entry(old
, head
, i_hash
) {
1334 if (old
->i_ino
!= ino
)
1336 if (old
->i_sb
!= sb
)
1338 spin_lock(&old
->i_lock
);
1339 if (old
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
1340 spin_unlock(&old
->i_lock
);
1346 spin_lock(&inode
->i_lock
);
1347 inode
->i_state
|= I_NEW
;
1348 hlist_add_head(&inode
->i_hash
, head
);
1349 spin_unlock(&inode
->i_lock
);
1350 spin_unlock(&inode_hash_lock
);
1354 spin_unlock(&old
->i_lock
);
1355 spin_unlock(&inode_hash_lock
);
1357 if (unlikely(!inode_unhashed(old
))) {
1364 EXPORT_SYMBOL(insert_inode_locked
);
1366 int insert_inode_locked4(struct inode
*inode
, unsigned long hashval
,
1367 int (*test
)(struct inode
*, void *), void *data
)
1369 struct super_block
*sb
= inode
->i_sb
;
1370 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1373 struct inode
*old
= NULL
;
1375 spin_lock(&inode_hash_lock
);
1376 hlist_for_each_entry(old
, head
, i_hash
) {
1377 if (old
->i_sb
!= sb
)
1379 if (!test(old
, data
))
1381 spin_lock(&old
->i_lock
);
1382 if (old
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
1383 spin_unlock(&old
->i_lock
);
1389 spin_lock(&inode
->i_lock
);
1390 inode
->i_state
|= I_NEW
;
1391 hlist_add_head(&inode
->i_hash
, head
);
1392 spin_unlock(&inode
->i_lock
);
1393 spin_unlock(&inode_hash_lock
);
1397 spin_unlock(&old
->i_lock
);
1398 spin_unlock(&inode_hash_lock
);
1400 if (unlikely(!inode_unhashed(old
))) {
1407 EXPORT_SYMBOL(insert_inode_locked4
);
1410 int generic_delete_inode(struct inode
*inode
)
1414 EXPORT_SYMBOL(generic_delete_inode
);
1417 * Called when we're dropping the last reference
1420 * Call the FS "drop_inode()" function, defaulting to
1421 * the legacy UNIX filesystem behaviour. If it tells
1422 * us to evict inode, do so. Otherwise, retain inode
1423 * in cache if fs is alive, sync and evict if fs is
1426 static void iput_final(struct inode
*inode
)
1428 struct super_block
*sb
= inode
->i_sb
;
1429 const struct super_operations
*op
= inode
->i_sb
->s_op
;
1432 WARN_ON(inode
->i_state
& I_NEW
);
1435 drop
= op
->drop_inode(inode
);
1437 drop
= generic_drop_inode(inode
);
1439 if (!drop
&& (sb
->s_flags
& MS_ACTIVE
)) {
1440 inode
->i_state
|= I_REFERENCED
;
1441 inode_add_lru(inode
);
1442 spin_unlock(&inode
->i_lock
);
1447 inode
->i_state
|= I_WILL_FREE
;
1448 spin_unlock(&inode
->i_lock
);
1449 write_inode_now(inode
, 1);
1450 spin_lock(&inode
->i_lock
);
1451 WARN_ON(inode
->i_state
& I_NEW
);
1452 inode
->i_state
&= ~I_WILL_FREE
;
1455 inode
->i_state
|= I_FREEING
;
1456 if (!list_empty(&inode
->i_lru
))
1457 inode_lru_list_del(inode
);
1458 spin_unlock(&inode
->i_lock
);
1464 * iput - put an inode
1465 * @inode: inode to put
1467 * Puts an inode, dropping its usage count. If the inode use count hits
1468 * zero, the inode is then freed and may also be destroyed.
1470 * Consequently, iput() can sleep.
1472 void iput(struct inode
*inode
)
1476 BUG_ON(inode
->i_state
& I_CLEAR
);
1478 if (atomic_dec_and_lock(&inode
->i_count
, &inode
->i_lock
)) {
1479 if (inode
->i_nlink
&& (inode
->i_state
& I_DIRTY_TIME
)) {
1480 atomic_inc(&inode
->i_count
);
1481 inode
->i_state
&= ~I_DIRTY_TIME
;
1482 spin_unlock(&inode
->i_lock
);
1483 trace_writeback_lazytime_iput(inode
);
1484 mark_inode_dirty_sync(inode
);
1490 EXPORT_SYMBOL(iput
);
1493 * bmap - find a block number in a file
1494 * @inode: inode of file
1495 * @block: block to find
1497 * Returns the block number on the device holding the inode that
1498 * is the disk block number for the block of the file requested.
1499 * That is, asked for block 4 of inode 1 the function will return the
1500 * disk block relative to the disk start that holds that block of the
1503 sector_t
bmap(struct inode
*inode
, sector_t block
)
1506 if (inode
->i_mapping
->a_ops
->bmap
)
1507 res
= inode
->i_mapping
->a_ops
->bmap(inode
->i_mapping
, block
);
1510 EXPORT_SYMBOL(bmap
);
1513 * With relative atime, only update atime if the previous atime is
1514 * earlier than either the ctime or mtime or if at least a day has
1515 * passed since the last atime update.
1517 static int relatime_need_update(struct vfsmount
*mnt
, struct inode
*inode
,
1518 struct timespec now
)
1521 if (!(mnt
->mnt_flags
& MNT_RELATIME
))
1524 * Is mtime younger than atime? If yes, update atime:
1526 if (timespec_compare(&inode
->i_mtime
, &inode
->i_atime
) >= 0)
1529 * Is ctime younger than atime? If yes, update atime:
1531 if (timespec_compare(&inode
->i_ctime
, &inode
->i_atime
) >= 0)
1535 * Is the previous atime value older than a day? If yes,
1538 if ((long)(now
.tv_sec
- inode
->i_atime
.tv_sec
) >= 24*60*60)
1541 * Good, we can skip the atime update:
1546 int generic_update_time(struct inode
*inode
, struct timespec
*time
, int flags
)
1548 int iflags
= I_DIRTY_TIME
;
1550 if (flags
& S_ATIME
)
1551 inode
->i_atime
= *time
;
1552 if (flags
& S_VERSION
)
1553 inode_inc_iversion(inode
);
1554 if (flags
& S_CTIME
)
1555 inode
->i_ctime
= *time
;
1556 if (flags
& S_MTIME
)
1557 inode
->i_mtime
= *time
;
1559 if (!(inode
->i_sb
->s_flags
& MS_LAZYTIME
) || (flags
& S_VERSION
))
1560 iflags
|= I_DIRTY_SYNC
;
1561 __mark_inode_dirty(inode
, iflags
);
1564 EXPORT_SYMBOL(generic_update_time
);
1567 * This does the actual work of updating an inodes time or version. Must have
1568 * had called mnt_want_write() before calling this.
1570 static int update_time(struct inode
*inode
, struct timespec
*time
, int flags
)
1572 int (*update_time
)(struct inode
*, struct timespec
*, int);
1574 update_time
= inode
->i_op
->update_time
? inode
->i_op
->update_time
:
1575 generic_update_time
;
1577 return update_time(inode
, time
, flags
);
1581 * touch_atime - update the access time
1582 * @path: the &struct path to update
1584 * Update the accessed time on an inode and mark it for writeback.
1585 * This function automatically handles read only file systems and media,
1586 * as well as the "noatime" flag and inode specific "noatime" markers.
1588 bool atime_needs_update(const struct path
*path
, struct inode
*inode
)
1590 struct vfsmount
*mnt
= path
->mnt
;
1591 struct timespec now
;
1593 if (inode
->i_flags
& S_NOATIME
)
1595 if (IS_NOATIME(inode
))
1597 if ((inode
->i_sb
->s_flags
& MS_NODIRATIME
) && S_ISDIR(inode
->i_mode
))
1600 if (mnt
->mnt_flags
& MNT_NOATIME
)
1602 if ((mnt
->mnt_flags
& MNT_NODIRATIME
) && S_ISDIR(inode
->i_mode
))
1605 now
= current_fs_time(inode
->i_sb
);
1607 if (!relatime_need_update(mnt
, inode
, now
))
1610 if (timespec_equal(&inode
->i_atime
, &now
))
1616 void touch_atime(const struct path
*path
)
1618 struct vfsmount
*mnt
= path
->mnt
;
1619 struct inode
*inode
= d_inode(path
->dentry
);
1620 struct timespec now
;
1622 if (!atime_needs_update(path
, inode
))
1625 if (!sb_start_write_trylock(inode
->i_sb
))
1628 if (__mnt_want_write(mnt
) != 0)
1631 * File systems can error out when updating inodes if they need to
1632 * allocate new space to modify an inode (such is the case for
1633 * Btrfs), but since we touch atime while walking down the path we
1634 * really don't care if we failed to update the atime of the file,
1635 * so just ignore the return value.
1636 * We may also fail on filesystems that have the ability to make parts
1637 * of the fs read only, e.g. subvolumes in Btrfs.
1639 now
= current_fs_time(inode
->i_sb
);
1640 update_time(inode
, &now
, S_ATIME
);
1641 __mnt_drop_write(mnt
);
1643 sb_end_write(inode
->i_sb
);
1645 EXPORT_SYMBOL(touch_atime
);
1648 * The logic we want is
1650 * if suid or (sgid and xgrp)
1653 int should_remove_suid(struct dentry
*dentry
)
1655 umode_t mode
= d_inode(dentry
)->i_mode
;
1658 /* suid always must be killed */
1659 if (unlikely(mode
& S_ISUID
))
1660 kill
= ATTR_KILL_SUID
;
1663 * sgid without any exec bits is just a mandatory locking mark; leave
1664 * it alone. If some exec bits are set, it's a real sgid; kill it.
1666 if (unlikely((mode
& S_ISGID
) && (mode
& S_IXGRP
)))
1667 kill
|= ATTR_KILL_SGID
;
1669 if (unlikely(kill
&& !capable(CAP_FSETID
) && S_ISREG(mode
)))
1674 EXPORT_SYMBOL(should_remove_suid
);
1676 static int __remove_suid(struct dentry
*dentry
, int kill
)
1678 struct iattr newattrs
;
1680 newattrs
.ia_valid
= ATTR_FORCE
| kill
;
1682 * Note we call this on write, so notify_change will not
1683 * encounter any conflicting delegations:
1685 return notify_change(dentry
, &newattrs
, NULL
);
1688 int file_remove_suid(struct file
*file
)
1690 struct dentry
*dentry
= file
->f_path
.dentry
;
1691 struct inode
*inode
= d_inode(dentry
);
1696 /* Fast path for nothing security related */
1697 if (IS_NOSEC(inode
))
1700 killsuid
= should_remove_suid(dentry
);
1701 killpriv
= security_inode_need_killpriv(dentry
);
1706 error
= security_inode_killpriv(dentry
);
1707 if (!error
&& killsuid
)
1708 error
= __remove_suid(dentry
, killsuid
);
1709 if (!error
&& (inode
->i_sb
->s_flags
& MS_NOSEC
))
1710 inode
->i_flags
|= S_NOSEC
;
1714 EXPORT_SYMBOL(file_remove_suid
);
1717 * file_update_time - update mtime and ctime time
1718 * @file: file accessed
1720 * Update the mtime and ctime members of an inode and mark the inode
1721 * for writeback. Note that this function is meant exclusively for
1722 * usage in the file write path of filesystems, and filesystems may
1723 * choose to explicitly ignore update via this function with the
1724 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1725 * timestamps are handled by the server. This can return an error for
1726 * file systems who need to allocate space in order to update an inode.
1729 int file_update_time(struct file
*file
)
1731 struct inode
*inode
= file_inode(file
);
1732 struct timespec now
;
1736 /* First try to exhaust all avenues to not sync */
1737 if (IS_NOCMTIME(inode
))
1740 now
= current_fs_time(inode
->i_sb
);
1741 if (!timespec_equal(&inode
->i_mtime
, &now
))
1744 if (!timespec_equal(&inode
->i_ctime
, &now
))
1747 if (IS_I_VERSION(inode
))
1748 sync_it
|= S_VERSION
;
1753 /* Finally allowed to write? Takes lock. */
1754 if (__mnt_want_write_file(file
))
1757 ret
= update_time(inode
, &now
, sync_it
);
1758 __mnt_drop_write_file(file
);
1762 EXPORT_SYMBOL(file_update_time
);
1764 int inode_needs_sync(struct inode
*inode
)
1768 if (S_ISDIR(inode
->i_mode
) && IS_DIRSYNC(inode
))
1772 EXPORT_SYMBOL(inode_needs_sync
);
1775 * If we try to find an inode in the inode hash while it is being
1776 * deleted, we have to wait until the filesystem completes its
1777 * deletion before reporting that it isn't found. This function waits
1778 * until the deletion _might_ have completed. Callers are responsible
1779 * to recheck inode state.
1781 * It doesn't matter if I_NEW is not set initially, a call to
1782 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1785 static void __wait_on_freeing_inode(struct inode
*inode
)
1787 wait_queue_head_t
*wq
;
1788 DEFINE_WAIT_BIT(wait
, &inode
->i_state
, __I_NEW
);
1789 wq
= bit_waitqueue(&inode
->i_state
, __I_NEW
);
1790 prepare_to_wait(wq
, &wait
.wait
, TASK_UNINTERRUPTIBLE
);
1791 spin_unlock(&inode
->i_lock
);
1792 spin_unlock(&inode_hash_lock
);
1794 finish_wait(wq
, &wait
.wait
);
1795 spin_lock(&inode_hash_lock
);
1798 static __initdata
unsigned long ihash_entries
;
1799 static int __init
set_ihash_entries(char *str
)
1803 ihash_entries
= simple_strtoul(str
, &str
, 0);
1806 __setup("ihash_entries=", set_ihash_entries
);
1809 * Initialize the waitqueues and inode hash table.
1811 void __init
inode_init_early(void)
1815 /* If hashes are distributed across NUMA nodes, defer
1816 * hash allocation until vmalloc space is available.
1822 alloc_large_system_hash("Inode-cache",
1823 sizeof(struct hlist_head
),
1832 for (loop
= 0; loop
< (1U << i_hash_shift
); loop
++)
1833 INIT_HLIST_HEAD(&inode_hashtable
[loop
]);
1836 void __init
inode_init(void)
1840 /* inode slab cache */
1841 inode_cachep
= kmem_cache_create("inode_cache",
1842 sizeof(struct inode
),
1844 (SLAB_RECLAIM_ACCOUNT
|SLAB_PANIC
|
1848 /* Hash may have been set up in inode_init_early */
1853 alloc_large_system_hash("Inode-cache",
1854 sizeof(struct hlist_head
),
1863 for (loop
= 0; loop
< (1U << i_hash_shift
); loop
++)
1864 INIT_HLIST_HEAD(&inode_hashtable
[loop
]);
1867 void init_special_inode(struct inode
*inode
, umode_t mode
, dev_t rdev
)
1869 inode
->i_mode
= mode
;
1870 if (S_ISCHR(mode
)) {
1871 inode
->i_fop
= &def_chr_fops
;
1872 inode
->i_rdev
= rdev
;
1873 } else if (S_ISBLK(mode
)) {
1874 inode
->i_fop
= &def_blk_fops
;
1875 inode
->i_rdev
= rdev
;
1876 } else if (S_ISFIFO(mode
))
1877 inode
->i_fop
= &pipefifo_fops
;
1878 else if (S_ISSOCK(mode
))
1879 ; /* leave it no_open_fops */
1881 printk(KERN_DEBUG
"init_special_inode: bogus i_mode (%o) for"
1882 " inode %s:%lu\n", mode
, inode
->i_sb
->s_id
,
1885 EXPORT_SYMBOL(init_special_inode
);
1888 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1890 * @dir: Directory inode
1891 * @mode: mode of the new inode
1893 void inode_init_owner(struct inode
*inode
, const struct inode
*dir
,
1896 inode
->i_uid
= current_fsuid();
1897 if (dir
&& dir
->i_mode
& S_ISGID
) {
1898 inode
->i_gid
= dir
->i_gid
;
1902 inode
->i_gid
= current_fsgid();
1903 inode
->i_mode
= mode
;
1905 EXPORT_SYMBOL(inode_init_owner
);
1908 * inode_owner_or_capable - check current task permissions to inode
1909 * @inode: inode being checked
1911 * Return true if current either has CAP_FOWNER in a namespace with the
1912 * inode owner uid mapped, or owns the file.
1914 bool inode_owner_or_capable(const struct inode
*inode
)
1916 struct user_namespace
*ns
;
1918 if (uid_eq(current_fsuid(), inode
->i_uid
))
1921 ns
= current_user_ns();
1922 if (ns_capable(ns
, CAP_FOWNER
) && kuid_has_mapping(ns
, inode
->i_uid
))
1926 EXPORT_SYMBOL(inode_owner_or_capable
);
1929 * Direct i/o helper functions
1931 static void __inode_dio_wait(struct inode
*inode
)
1933 wait_queue_head_t
*wq
= bit_waitqueue(&inode
->i_state
, __I_DIO_WAKEUP
);
1934 DEFINE_WAIT_BIT(q
, &inode
->i_state
, __I_DIO_WAKEUP
);
1937 prepare_to_wait(wq
, &q
.wait
, TASK_UNINTERRUPTIBLE
);
1938 if (atomic_read(&inode
->i_dio_count
))
1940 } while (atomic_read(&inode
->i_dio_count
));
1941 finish_wait(wq
, &q
.wait
);
1945 * inode_dio_wait - wait for outstanding DIO requests to finish
1946 * @inode: inode to wait for
1948 * Waits for all pending direct I/O requests to finish so that we can
1949 * proceed with a truncate or equivalent operation.
1951 * Must be called under a lock that serializes taking new references
1952 * to i_dio_count, usually by inode->i_mutex.
1954 void inode_dio_wait(struct inode
*inode
)
1956 if (atomic_read(&inode
->i_dio_count
))
1957 __inode_dio_wait(inode
);
1959 EXPORT_SYMBOL(inode_dio_wait
);
1962 * inode_set_flags - atomically set some inode flags
1964 * Note: the caller should be holding i_mutex, or else be sure that
1965 * they have exclusive access to the inode structure (i.e., while the
1966 * inode is being instantiated). The reason for the cmpxchg() loop
1967 * --- which wouldn't be necessary if all code paths which modify
1968 * i_flags actually followed this rule, is that there is at least one
1969 * code path which doesn't today --- for example,
1970 * __generic_file_aio_write() calls file_remove_suid() without holding
1971 * i_mutex --- so we use cmpxchg() out of an abundance of caution.
1973 * In the long run, i_mutex is overkill, and we should probably look
1974 * at using the i_lock spinlock to protect i_flags, and then make sure
1975 * it is so documented in include/linux/fs.h and that all code follows
1976 * the locking convention!!
1978 void inode_set_flags(struct inode
*inode
, unsigned int flags
,
1981 unsigned int old_flags
, new_flags
;
1983 WARN_ON_ONCE(flags
& ~mask
);
1985 old_flags
= ACCESS_ONCE(inode
->i_flags
);
1986 new_flags
= (old_flags
& ~mask
) | flags
;
1987 } while (unlikely(cmpxchg(&inode
->i_flags
, old_flags
,
1988 new_flags
) != old_flags
));
1990 EXPORT_SYMBOL(inode_set_flags
);