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 intialisation
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;
143 i_uid_write(inode, 0);
144 i_gid_write(inode, 0);
145 atomic_set(&inode->i_writecount, 0);
149 inode->i_generation = 0;
150 inode->i_pipe = NULL;
151 inode->i_bdev = NULL;
152 inode->i_cdev = NULL;
153 inode->i_link = NULL;
155 inode->dirtied_when = 0;
157 #ifdef CONFIG_CGROUP_WRITEBACK
158 inode->i_wb_frn_winner = 0;
159 inode->i_wb_frn_avg_time = 0;
160 inode->i_wb_frn_history = 0;
163 if (security_inode_alloc(inode))
165 spin_lock_init(&inode->i_lock);
166 lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
168 mutex_init(&inode->i_mutex);
169 lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
171 atomic_set(&inode->i_dio_count, 0);
173 mapping->a_ops = &empty_aops;
174 mapping->host = inode;
176 atomic_set(&mapping->i_mmap_writable, 0);
177 mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
178 mapping->private_data = NULL;
179 mapping->writeback_index = 0;
180 inode->i_private = NULL;
181 inode->i_mapping = mapping;
182 INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */
183 #ifdef CONFIG_FS_POSIX_ACL
184 inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
187 #ifdef CONFIG_FSNOTIFY
188 inode->i_fsnotify_mask = 0;
190 inode->i_flctx = NULL;
191 this_cpu_inc(nr_inodes);
197 EXPORT_SYMBOL(inode_init_always);
199 static struct inode *alloc_inode(struct super_block *sb)
203 if (sb->s_op->alloc_inode)
204 inode = sb->s_op->alloc_inode(sb);
206 inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
211 if (unlikely(inode_init_always(sb, inode))) {
212 if (inode->i_sb->s_op->destroy_inode)
213 inode->i_sb->s_op->destroy_inode(inode);
215 kmem_cache_free(inode_cachep, inode);
222 void free_inode_nonrcu(struct inode *inode)
224 kmem_cache_free(inode_cachep, inode);
226 EXPORT_SYMBOL(free_inode_nonrcu);
228 void __destroy_inode(struct inode *inode)
230 BUG_ON(inode_has_buffers(inode));
231 inode_detach_wb(inode);
232 security_inode_free(inode);
233 fsnotify_inode_delete(inode);
234 locks_free_lock_context(inode->i_flctx);
235 if (!inode->i_nlink) {
236 WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0);
237 atomic_long_dec(&inode->i_sb->s_remove_count);
240 #ifdef CONFIG_FS_POSIX_ACL
241 if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
242 posix_acl_release(inode->i_acl);
243 if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
244 posix_acl_release(inode->i_default_acl);
246 this_cpu_dec(nr_inodes);
248 EXPORT_SYMBOL(__destroy_inode);
250 static void i_callback(struct rcu_head *head)
252 struct inode *inode = container_of(head, struct inode, i_rcu);
253 kmem_cache_free(inode_cachep, inode);
256 static void destroy_inode(struct inode *inode)
258 BUG_ON(!list_empty(&inode->i_lru));
259 __destroy_inode(inode);
260 if (inode->i_sb->s_op->destroy_inode)
261 inode->i_sb->s_op->destroy_inode(inode);
263 call_rcu(&inode->i_rcu, i_callback);
267 * drop_nlink - directly drop an inode's link count
270 * This is a low-level filesystem helper to replace any
271 * direct filesystem manipulation of i_nlink. In cases
272 * where we are attempting to track writes to the
273 * filesystem, a decrement to zero means an imminent
274 * write when the file is truncated and actually unlinked
277 void drop_nlink(struct inode *inode)
279 WARN_ON(inode->i_nlink == 0);
282 atomic_long_inc(&inode->i_sb->s_remove_count);
284 EXPORT_SYMBOL(drop_nlink);
287 * clear_nlink - directly zero an inode's link count
290 * This is a low-level filesystem helper to replace any
291 * direct filesystem manipulation of i_nlink. See
292 * drop_nlink() for why we care about i_nlink hitting zero.
294 void clear_nlink(struct inode *inode)
296 if (inode->i_nlink) {
297 inode->__i_nlink = 0;
298 atomic_long_inc(&inode->i_sb->s_remove_count);
301 EXPORT_SYMBOL(clear_nlink);
304 * set_nlink - directly set an inode's link count
306 * @nlink: new nlink (should be non-zero)
308 * This is a low-level filesystem helper to replace any
309 * direct filesystem manipulation of i_nlink.
311 void set_nlink(struct inode *inode, unsigned int nlink)
316 /* Yes, some filesystems do change nlink from zero to one */
317 if (inode->i_nlink == 0)
318 atomic_long_dec(&inode->i_sb->s_remove_count);
320 inode->__i_nlink = nlink;
323 EXPORT_SYMBOL(set_nlink);
326 * inc_nlink - directly increment an inode's link count
329 * This is a low-level filesystem helper to replace any
330 * direct filesystem manipulation of i_nlink. Currently,
331 * it is only here for parity with dec_nlink().
333 void inc_nlink(struct inode *inode)
335 if (unlikely(inode->i_nlink == 0)) {
336 WARN_ON(!(inode->i_state & I_LINKABLE));
337 atomic_long_dec(&inode->i_sb->s_remove_count);
342 EXPORT_SYMBOL(inc_nlink);
344 void address_space_init_once(struct address_space *mapping)
346 memset(mapping, 0, sizeof(*mapping));
347 INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
348 spin_lock_init(&mapping->tree_lock);
349 init_rwsem(&mapping->i_mmap_rwsem);
350 INIT_LIST_HEAD(&mapping->private_list);
351 spin_lock_init(&mapping->private_lock);
352 mapping->i_mmap = RB_ROOT;
354 EXPORT_SYMBOL(address_space_init_once);
357 * These are initializations that only need to be done
358 * once, because the fields are idempotent across use
359 * of the inode, so let the slab aware of that.
361 void inode_init_once(struct inode *inode)
363 memset(inode, 0, sizeof(*inode));
364 INIT_HLIST_NODE(&inode->i_hash);
365 INIT_LIST_HEAD(&inode->i_devices);
366 INIT_LIST_HEAD(&inode->i_io_list);
367 INIT_LIST_HEAD(&inode->i_lru);
368 address_space_init_once(&inode->i_data);
369 i_size_ordered_init(inode);
370 #ifdef CONFIG_FSNOTIFY
371 INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
374 EXPORT_SYMBOL(inode_init_once);
376 static void init_once(void *foo)
378 struct inode *inode = (struct inode *) foo;
380 inode_init_once(inode);
384 * inode->i_lock must be held
386 void __iget(struct inode *inode)
388 atomic_inc(&inode->i_count);
392 * get additional reference to inode; caller must already hold one.
394 void ihold(struct inode *inode)
396 WARN_ON(atomic_inc_return(&inode->i_count) < 2);
398 EXPORT_SYMBOL(ihold);
400 static void inode_lru_list_add(struct inode *inode)
402 if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
403 this_cpu_inc(nr_unused);
407 * Add inode to LRU if needed (inode is unused and clean).
409 * Needs inode->i_lock held.
411 void inode_add_lru(struct inode *inode)
413 if (!(inode->i_state & (I_DIRTY_ALL | I_SYNC |
414 I_FREEING | I_WILL_FREE)) &&
415 !atomic_read(&inode->i_count) && inode->i_sb->s_flags & MS_ACTIVE)
416 inode_lru_list_add(inode);
420 static void inode_lru_list_del(struct inode *inode)
423 if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
424 this_cpu_dec(nr_unused);
428 * inode_sb_list_add - add inode to the superblock list of inodes
429 * @inode: inode to add
431 void inode_sb_list_add(struct inode *inode)
433 spin_lock(&inode->i_sb->s_inode_list_lock);
434 list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
435 spin_unlock(&inode->i_sb->s_inode_list_lock);
437 EXPORT_SYMBOL_GPL(inode_sb_list_add);
439 static inline void inode_sb_list_del(struct inode *inode)
441 if (!list_empty(&inode->i_sb_list)) {
442 spin_lock(&inode->i_sb->s_inode_list_lock);
443 list_del_init(&inode->i_sb_list);
444 spin_unlock(&inode->i_sb->s_inode_list_lock);
448 static unsigned long hash(struct super_block *sb, unsigned long hashval)
452 tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
454 tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
455 return tmp & i_hash_mask;
459 * __insert_inode_hash - hash an inode
460 * @inode: unhashed inode
461 * @hashval: unsigned long value used to locate this object in the
464 * Add an inode to the inode hash for this superblock.
466 void __insert_inode_hash(struct inode *inode, unsigned long hashval)
468 struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
470 spin_lock(&inode_hash_lock);
471 spin_lock(&inode->i_lock);
472 hlist_add_head(&inode->i_hash, b);
473 spin_unlock(&inode->i_lock);
474 spin_unlock(&inode_hash_lock);
476 EXPORT_SYMBOL(__insert_inode_hash);
479 * __remove_inode_hash - remove an inode from the hash
480 * @inode: inode to unhash
482 * Remove an inode from the superblock.
484 void __remove_inode_hash(struct inode *inode)
486 spin_lock(&inode_hash_lock);
487 spin_lock(&inode->i_lock);
488 hlist_del_init(&inode->i_hash);
489 spin_unlock(&inode->i_lock);
490 spin_unlock(&inode_hash_lock);
492 EXPORT_SYMBOL(__remove_inode_hash);
494 void clear_inode(struct inode *inode)
498 * We have to cycle tree_lock here because reclaim can be still in the
499 * process of removing the last page (in __delete_from_page_cache())
500 * and we must not free mapping under it.
502 spin_lock_irq(&inode->i_data.tree_lock);
503 BUG_ON(inode->i_data.nrpages);
504 BUG_ON(inode->i_data.nrshadows);
505 spin_unlock_irq(&inode->i_data.tree_lock);
506 BUG_ON(!list_empty(&inode->i_data.private_list));
507 BUG_ON(!(inode->i_state & I_FREEING));
508 BUG_ON(inode->i_state & I_CLEAR);
509 /* don't need i_lock here, no concurrent mods to i_state */
510 inode->i_state = I_FREEING | I_CLEAR;
512 EXPORT_SYMBOL(clear_inode);
515 * Free the inode passed in, removing it from the lists it is still connected
516 * to. We remove any pages still attached to the inode and wait for any IO that
517 * is still in progress before finally destroying the inode.
519 * An inode must already be marked I_FREEING so that we avoid the inode being
520 * moved back onto lists if we race with other code that manipulates the lists
521 * (e.g. writeback_single_inode). The caller is responsible for setting this.
523 * An inode must already be removed from the LRU list before being evicted from
524 * the cache. This should occur atomically with setting the I_FREEING state
525 * flag, so no inodes here should ever be on the LRU when being evicted.
527 static void evict(struct inode *inode)
529 const struct super_operations *op = inode->i_sb->s_op;
531 BUG_ON(!(inode->i_state & I_FREEING));
532 BUG_ON(!list_empty(&inode->i_lru));
534 if (!list_empty(&inode->i_io_list))
535 inode_io_list_del(inode);
537 inode_sb_list_del(inode);
540 * Wait for flusher thread to be done with the inode so that filesystem
541 * does not start destroying it while writeback is still running. Since
542 * the inode has I_FREEING set, flusher thread won't start new work on
543 * the inode. We just have to wait for running writeback to finish.
545 inode_wait_for_writeback(inode);
547 if (op->evict_inode) {
548 op->evict_inode(inode);
550 truncate_inode_pages_final(&inode->i_data);
553 if (S_ISBLK(inode->i_mode) && inode->i_bdev)
555 if (S_ISCHR(inode->i_mode) && inode->i_cdev)
558 remove_inode_hash(inode);
560 spin_lock(&inode->i_lock);
561 wake_up_bit(&inode->i_state, __I_NEW);
562 BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
563 spin_unlock(&inode->i_lock);
565 destroy_inode(inode);
569 * dispose_list - dispose of the contents of a local list
570 * @head: the head of the list to free
572 * Dispose-list gets a local list with local inodes in it, so it doesn't
573 * need to worry about list corruption and SMP locks.
575 static void dispose_list(struct list_head *head)
577 while (!list_empty(head)) {
580 inode = list_first_entry(head, struct inode, i_lru);
581 list_del_init(&inode->i_lru);
589 * evict_inodes - evict all evictable inodes for a superblock
590 * @sb: superblock to operate on
592 * Make sure that no inodes with zero refcount are retained. This is
593 * called by superblock shutdown after having MS_ACTIVE flag removed,
594 * so any inode reaching zero refcount during or after that call will
595 * be immediately evicted.
597 void evict_inodes(struct super_block *sb)
599 struct inode *inode, *next;
603 spin_lock(&sb->s_inode_list_lock);
604 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
605 if (atomic_read(&inode->i_count))
608 spin_lock(&inode->i_lock);
609 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
610 spin_unlock(&inode->i_lock);
614 inode->i_state |= I_FREEING;
615 inode_lru_list_del(inode);
616 spin_unlock(&inode->i_lock);
617 list_add(&inode->i_lru, &dispose);
620 * We can have a ton of inodes to evict at unmount time given
621 * enough memory, check to see if we need to go to sleep for a
622 * bit so we don't livelock.
624 if (need_resched()) {
625 spin_unlock(&sb->s_inode_list_lock);
627 dispose_list(&dispose);
631 spin_unlock(&sb->s_inode_list_lock);
633 dispose_list(&dispose);
637 * invalidate_inodes - attempt to free all inodes on a superblock
638 * @sb: superblock to operate on
639 * @kill_dirty: flag to guide handling of dirty inodes
641 * Attempts to free all inodes for a given superblock. If there were any
642 * busy inodes return a non-zero value, else zero.
643 * If @kill_dirty is set, discard dirty inodes too, otherwise treat
646 int invalidate_inodes(struct super_block *sb, bool kill_dirty)
649 struct inode *inode, *next;
652 spin_lock(&sb->s_inode_list_lock);
653 list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
654 spin_lock(&inode->i_lock);
655 if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
656 spin_unlock(&inode->i_lock);
659 if (inode->i_state & I_DIRTY_ALL && !kill_dirty) {
660 spin_unlock(&inode->i_lock);
664 if (atomic_read(&inode->i_count)) {
665 spin_unlock(&inode->i_lock);
670 inode->i_state |= I_FREEING;
671 inode_lru_list_del(inode);
672 spin_unlock(&inode->i_lock);
673 list_add(&inode->i_lru, &dispose);
675 spin_unlock(&sb->s_inode_list_lock);
677 dispose_list(&dispose);
683 * Isolate the inode from the LRU in preparation for freeing it.
685 * Any inodes which are pinned purely because of attached pagecache have their
686 * pagecache removed. If the inode has metadata buffers attached to
687 * mapping->private_list then try to remove them.
689 * If the inode has the I_REFERENCED flag set, then it means that it has been
690 * used recently - the flag is set in iput_final(). When we encounter such an
691 * inode, clear the flag and move it to the back of the LRU so it gets another
692 * pass through the LRU before it gets reclaimed. This is necessary because of
693 * the fact we are doing lazy LRU updates to minimise lock contention so the
694 * LRU does not have strict ordering. Hence we don't want to reclaim inodes
695 * with this flag set because they are the inodes that are out of order.
697 static enum lru_status inode_lru_isolate(struct list_head *item,
698 struct list_lru_one *lru, spinlock_t *lru_lock, void *arg)
700 struct list_head *freeable = arg;
701 struct inode *inode = container_of(item, struct inode, i_lru);
704 * we are inverting the lru lock/inode->i_lock here, so use a trylock.
705 * If we fail to get the lock, just skip it.
707 if (!spin_trylock(&inode->i_lock))
711 * Referenced or dirty inodes are still in use. Give them another pass
712 * through the LRU as we canot reclaim them now.
714 if (atomic_read(&inode->i_count) ||
715 (inode->i_state & ~I_REFERENCED)) {
716 list_lru_isolate(lru, &inode->i_lru);
717 spin_unlock(&inode->i_lock);
718 this_cpu_dec(nr_unused);
722 /* recently referenced inodes get one more pass */
723 if (inode->i_state & I_REFERENCED) {
724 inode->i_state &= ~I_REFERENCED;
725 spin_unlock(&inode->i_lock);
729 if (inode_has_buffers(inode) || inode->i_data.nrpages) {
731 spin_unlock(&inode->i_lock);
732 spin_unlock(lru_lock);
733 if (remove_inode_buffers(inode)) {
735 reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
736 if (current_is_kswapd())
737 __count_vm_events(KSWAPD_INODESTEAL, reap);
739 __count_vm_events(PGINODESTEAL, reap);
740 if (current->reclaim_state)
741 current->reclaim_state->reclaimed_slab += reap;
748 WARN_ON(inode->i_state & I_NEW);
749 inode->i_state |= I_FREEING;
750 list_lru_isolate_move(lru, &inode->i_lru, freeable);
751 spin_unlock(&inode->i_lock);
753 this_cpu_dec(nr_unused);
758 * Walk the superblock inode LRU for freeable inodes and attempt to free them.
759 * This is called from the superblock shrinker function with a number of inodes
760 * to trim from the LRU. Inodes to be freed are moved to a temporary list and
761 * then are freed outside inode_lock by dispose_list().
763 long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
768 freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
769 inode_lru_isolate, &freeable);
770 dispose_list(&freeable);
774 static void __wait_on_freeing_inode(struct inode *inode);
776 * Called with the inode lock held.
778 static struct inode *find_inode(struct super_block *sb,
779 struct hlist_head *head,
780 int (*test)(struct inode *, void *),
783 struct inode *inode = NULL;
786 hlist_for_each_entry(inode, head, i_hash) {
787 if (inode->i_sb != sb)
789 if (!test(inode, data))
791 spin_lock(&inode->i_lock);
792 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
793 __wait_on_freeing_inode(inode);
797 spin_unlock(&inode->i_lock);
804 * find_inode_fast is the fast path version of find_inode, see the comment at
805 * iget_locked for details.
807 static struct inode *find_inode_fast(struct super_block *sb,
808 struct hlist_head *head, unsigned long ino)
810 struct inode *inode = NULL;
813 hlist_for_each_entry(inode, head, i_hash) {
814 if (inode->i_ino != ino)
816 if (inode->i_sb != sb)
818 spin_lock(&inode->i_lock);
819 if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
820 __wait_on_freeing_inode(inode);
824 spin_unlock(&inode->i_lock);
831 * Each cpu owns a range of LAST_INO_BATCH numbers.
832 * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
833 * to renew the exhausted range.
835 * This does not significantly increase overflow rate because every CPU can
836 * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
837 * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
838 * 2^32 range, and is a worst-case. Even a 50% wastage would only increase
839 * overflow rate by 2x, which does not seem too significant.
841 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
842 * error if st_ino won't fit in target struct field. Use 32bit counter
843 * here to attempt to avoid that.
845 #define LAST_INO_BATCH 1024
846 static DEFINE_PER_CPU(unsigned int, last_ino);
848 unsigned int get_next_ino(void)
850 unsigned int *p = &get_cpu_var(last_ino);
851 unsigned int res = *p;
854 if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
855 static atomic_t shared_last_ino;
856 int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
858 res = next - LAST_INO_BATCH;
863 /* get_next_ino should not provide a 0 inode number */
867 put_cpu_var(last_ino);
870 EXPORT_SYMBOL(get_next_ino);
873 * new_inode_pseudo - obtain an inode
876 * Allocates a new inode for given superblock.
877 * Inode wont be chained in superblock s_inodes list
879 * - fs can't be unmount
880 * - quotas, fsnotify, writeback can't work
882 struct inode *new_inode_pseudo(struct super_block *sb)
884 struct inode *inode = alloc_inode(sb);
887 spin_lock(&inode->i_lock);
889 spin_unlock(&inode->i_lock);
890 INIT_LIST_HEAD(&inode->i_sb_list);
896 * new_inode - obtain an inode
899 * Allocates a new inode for given superblock. The default gfp_mask
900 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
901 * If HIGHMEM pages are unsuitable or it is known that pages allocated
902 * for the page cache are not reclaimable or migratable,
903 * mapping_set_gfp_mask() must be called with suitable flags on the
904 * newly created inode's mapping
907 struct inode *new_inode(struct super_block *sb)
911 spin_lock_prefetch(&sb->s_inode_list_lock);
913 inode = new_inode_pseudo(sb);
915 inode_sb_list_add(inode);
918 EXPORT_SYMBOL(new_inode);
920 #ifdef CONFIG_DEBUG_LOCK_ALLOC
921 void lockdep_annotate_inode_mutex_key(struct inode *inode)
923 if (S_ISDIR(inode->i_mode)) {
924 struct file_system_type *type = inode->i_sb->s_type;
926 /* Set new key only if filesystem hasn't already changed it */
927 if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) {
929 * ensure nobody is actually holding i_mutex
931 mutex_destroy(&inode->i_mutex);
932 mutex_init(&inode->i_mutex);
933 lockdep_set_class(&inode->i_mutex,
934 &type->i_mutex_dir_key);
938 EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key);
942 * unlock_new_inode - clear the I_NEW state and wake up any waiters
943 * @inode: new inode to unlock
945 * Called when the inode is fully initialised to clear the new state of the
946 * inode and wake up anyone waiting for the inode to finish initialisation.
948 void unlock_new_inode(struct inode *inode)
950 lockdep_annotate_inode_mutex_key(inode);
951 spin_lock(&inode->i_lock);
952 WARN_ON(!(inode->i_state & I_NEW));
953 inode->i_state &= ~I_NEW;
955 wake_up_bit(&inode->i_state, __I_NEW);
956 spin_unlock(&inode->i_lock);
958 EXPORT_SYMBOL(unlock_new_inode);
961 * lock_two_nondirectories - take two i_mutexes on non-directory objects
963 * Lock any non-NULL argument that is not a directory.
964 * Zero, one or two objects may be locked by this function.
966 * @inode1: first inode to lock
967 * @inode2: second inode to lock
969 void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
972 swap(inode1, inode2);
974 if (inode1 && !S_ISDIR(inode1->i_mode))
975 mutex_lock(&inode1->i_mutex);
976 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
977 mutex_lock_nested(&inode2->i_mutex, I_MUTEX_NONDIR2);
979 EXPORT_SYMBOL(lock_two_nondirectories);
982 * unlock_two_nondirectories - release locks from lock_two_nondirectories()
983 * @inode1: first inode to unlock
984 * @inode2: second inode to unlock
986 void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2)
988 if (inode1 && !S_ISDIR(inode1->i_mode))
989 mutex_unlock(&inode1->i_mutex);
990 if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
991 mutex_unlock(&inode2->i_mutex);
993 EXPORT_SYMBOL(unlock_two_nondirectories);
996 * iget5_locked - obtain an inode from a mounted file system
997 * @sb: super block of file system
998 * @hashval: hash value (usually inode number) to get
999 * @test: callback used for comparisons between inodes
1000 * @set: callback used to initialize a new struct inode
1001 * @data: opaque data pointer to pass to @test and @set
1003 * Search for the inode specified by @hashval and @data in the inode cache,
1004 * and if present it is return it with an increased reference count. This is
1005 * a generalized version of iget_locked() for file systems where the inode
1006 * number is not sufficient for unique identification of an inode.
1008 * If the inode is not in cache, allocate a new inode and return it locked,
1009 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1010 * before unlocking it via unlock_new_inode().
1012 * Note both @test and @set are called with the inode_hash_lock held, so can't
1015 struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
1016 int (*test)(struct inode *, void *),
1017 int (*set)(struct inode *, void *), void *data)
1019 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1020 struct inode *inode;
1022 spin_lock(&inode_hash_lock);
1023 inode = find_inode(sb, head, test, data);
1024 spin_unlock(&inode_hash_lock);
1027 wait_on_inode(inode);
1031 inode = alloc_inode(sb);
1035 spin_lock(&inode_hash_lock);
1036 /* We released the lock, so.. */
1037 old = find_inode(sb, head, test, data);
1039 if (set(inode, data))
1042 spin_lock(&inode->i_lock);
1043 inode->i_state = I_NEW;
1044 hlist_add_head(&inode->i_hash, head);
1045 spin_unlock(&inode->i_lock);
1046 inode_sb_list_add(inode);
1047 spin_unlock(&inode_hash_lock);
1049 /* Return the locked inode with I_NEW set, the
1050 * caller is responsible for filling in the contents
1056 * Uhhuh, somebody else created the same inode under
1057 * us. Use the old inode instead of the one we just
1060 spin_unlock(&inode_hash_lock);
1061 destroy_inode(inode);
1063 wait_on_inode(inode);
1068 spin_unlock(&inode_hash_lock);
1069 destroy_inode(inode);
1072 EXPORT_SYMBOL(iget5_locked);
1075 * iget_locked - obtain an inode from a mounted file system
1076 * @sb: super block of file system
1077 * @ino: inode number to get
1079 * Search for the inode specified by @ino in the inode cache and if present
1080 * return it with an increased reference count. This is for file systems
1081 * where the inode number is sufficient for unique identification of an inode.
1083 * If the inode is not in cache, allocate a new inode and return it locked,
1084 * hashed, and with the I_NEW flag set. The file system gets to fill it in
1085 * before unlocking it via unlock_new_inode().
1087 struct inode *iget_locked(struct super_block *sb, unsigned long ino)
1089 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1090 struct inode *inode;
1092 spin_lock(&inode_hash_lock);
1093 inode = find_inode_fast(sb, head, ino);
1094 spin_unlock(&inode_hash_lock);
1096 wait_on_inode(inode);
1100 inode = alloc_inode(sb);
1104 spin_lock(&inode_hash_lock);
1105 /* We released the lock, so.. */
1106 old = find_inode_fast(sb, head, ino);
1109 spin_lock(&inode->i_lock);
1110 inode->i_state = I_NEW;
1111 hlist_add_head(&inode->i_hash, head);
1112 spin_unlock(&inode->i_lock);
1113 inode_sb_list_add(inode);
1114 spin_unlock(&inode_hash_lock);
1116 /* Return the locked inode with I_NEW set, the
1117 * caller is responsible for filling in the contents
1123 * Uhhuh, somebody else created the same inode under
1124 * us. Use the old inode instead of the one we just
1127 spin_unlock(&inode_hash_lock);
1128 destroy_inode(inode);
1130 wait_on_inode(inode);
1134 EXPORT_SYMBOL(iget_locked);
1137 * search the inode cache for a matching inode number.
1138 * If we find one, then the inode number we are trying to
1139 * allocate is not unique and so we should not use it.
1141 * Returns 1 if the inode number is unique, 0 if it is not.
1143 static int test_inode_iunique(struct super_block *sb, unsigned long ino)
1145 struct hlist_head *b = inode_hashtable + hash(sb, ino);
1146 struct inode *inode;
1148 spin_lock(&inode_hash_lock);
1149 hlist_for_each_entry(inode, b, i_hash) {
1150 if (inode->i_ino == ino && inode->i_sb == sb) {
1151 spin_unlock(&inode_hash_lock);
1155 spin_unlock(&inode_hash_lock);
1161 * iunique - get a unique inode number
1163 * @max_reserved: highest reserved inode number
1165 * Obtain an inode number that is unique on the system for a given
1166 * superblock. This is used by file systems that have no natural
1167 * permanent inode numbering system. An inode number is returned that
1168 * is higher than the reserved limit but unique.
1171 * With a large number of inodes live on the file system this function
1172 * currently becomes quite slow.
1174 ino_t iunique(struct super_block *sb, ino_t max_reserved)
1177 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
1178 * error if st_ino won't fit in target struct field. Use 32bit counter
1179 * here to attempt to avoid that.
1181 static DEFINE_SPINLOCK(iunique_lock);
1182 static unsigned int counter;
1185 spin_lock(&iunique_lock);
1187 if (counter <= max_reserved)
1188 counter = max_reserved + 1;
1190 } while (!test_inode_iunique(sb, res));
1191 spin_unlock(&iunique_lock);
1195 EXPORT_SYMBOL(iunique);
1197 struct inode *igrab(struct inode *inode)
1199 spin_lock(&inode->i_lock);
1200 if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) {
1202 spin_unlock(&inode->i_lock);
1204 spin_unlock(&inode->i_lock);
1206 * Handle the case where s_op->clear_inode is not been
1207 * called yet, and somebody is calling igrab
1208 * while the inode is getting freed.
1214 EXPORT_SYMBOL(igrab);
1217 * ilookup5_nowait - search for an inode in the inode cache
1218 * @sb: super block of file system to search
1219 * @hashval: hash value (usually inode number) to search for
1220 * @test: callback used for comparisons between inodes
1221 * @data: opaque data pointer to pass to @test
1223 * Search for the inode specified by @hashval and @data in the inode cache.
1224 * If the inode is in the cache, the inode is returned with an incremented
1227 * Note: I_NEW is not waited upon so you have to be very careful what you do
1228 * with the returned inode. You probably should be using ilookup5() instead.
1230 * Note2: @test is called with the inode_hash_lock held, so can't sleep.
1232 struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
1233 int (*test)(struct inode *, void *), void *data)
1235 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1236 struct inode *inode;
1238 spin_lock(&inode_hash_lock);
1239 inode = find_inode(sb, head, test, data);
1240 spin_unlock(&inode_hash_lock);
1244 EXPORT_SYMBOL(ilookup5_nowait);
1247 * ilookup5 - 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 * and if the inode is in the cache, return the inode with an incremented
1255 * reference count. Waits on I_NEW before returning the inode.
1256 * returned with an incremented reference count.
1258 * This is a generalized version of ilookup() for file systems where the
1259 * inode number is not sufficient for unique identification of an inode.
1261 * Note: @test is called with the inode_hash_lock held, so can't sleep.
1263 struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
1264 int (*test)(struct inode *, void *), void *data)
1266 struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
1269 wait_on_inode(inode);
1272 EXPORT_SYMBOL(ilookup5);
1275 * ilookup - search for an inode in the inode cache
1276 * @sb: super block of file system to search
1277 * @ino: inode number to search for
1279 * Search for the inode @ino in the inode cache, and if the inode is in the
1280 * cache, the inode is returned with an incremented reference count.
1282 struct inode *ilookup(struct super_block *sb, unsigned long ino)
1284 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1285 struct inode *inode;
1287 spin_lock(&inode_hash_lock);
1288 inode = find_inode_fast(sb, head, ino);
1289 spin_unlock(&inode_hash_lock);
1292 wait_on_inode(inode);
1295 EXPORT_SYMBOL(ilookup);
1298 * find_inode_nowait - find an inode in the inode cache
1299 * @sb: super block of file system to search
1300 * @hashval: hash value (usually inode number) to search for
1301 * @match: callback used for comparisons between inodes
1302 * @data: opaque data pointer to pass to @match
1304 * Search for the inode specified by @hashval and @data in the inode
1305 * cache, where the helper function @match will return 0 if the inode
1306 * does not match, 1 if the inode does match, and -1 if the search
1307 * should be stopped. The @match function must be responsible for
1308 * taking the i_lock spin_lock and checking i_state for an inode being
1309 * freed or being initialized, and incrementing the reference count
1310 * before returning 1. It also must not sleep, since it is called with
1311 * the inode_hash_lock spinlock held.
1313 * This is a even more generalized version of ilookup5() when the
1314 * function must never block --- find_inode() can block in
1315 * __wait_on_freeing_inode() --- or when the caller can not increment
1316 * the reference count because the resulting iput() might cause an
1317 * inode eviction. The tradeoff is that the @match funtion must be
1318 * very carefully implemented.
1320 struct inode *find_inode_nowait(struct super_block *sb,
1321 unsigned long hashval,
1322 int (*match)(struct inode *, unsigned long,
1326 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1327 struct inode *inode, *ret_inode = NULL;
1330 spin_lock(&inode_hash_lock);
1331 hlist_for_each_entry(inode, head, i_hash) {
1332 if (inode->i_sb != sb)
1334 mval = match(inode, hashval, data);
1342 spin_unlock(&inode_hash_lock);
1345 EXPORT_SYMBOL(find_inode_nowait);
1347 int insert_inode_locked(struct inode *inode)
1349 struct super_block *sb = inode->i_sb;
1350 ino_t ino = inode->i_ino;
1351 struct hlist_head *head = inode_hashtable + hash(sb, ino);
1354 struct inode *old = NULL;
1355 spin_lock(&inode_hash_lock);
1356 hlist_for_each_entry(old, head, i_hash) {
1357 if (old->i_ino != ino)
1359 if (old->i_sb != sb)
1361 spin_lock(&old->i_lock);
1362 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1363 spin_unlock(&old->i_lock);
1369 spin_lock(&inode->i_lock);
1370 inode->i_state |= I_NEW;
1371 hlist_add_head(&inode->i_hash, head);
1372 spin_unlock(&inode->i_lock);
1373 spin_unlock(&inode_hash_lock);
1377 spin_unlock(&old->i_lock);
1378 spin_unlock(&inode_hash_lock);
1380 if (unlikely(!inode_unhashed(old))) {
1387 EXPORT_SYMBOL(insert_inode_locked);
1389 int insert_inode_locked4(struct inode *inode, unsigned long hashval,
1390 int (*test)(struct inode *, void *), void *data)
1392 struct super_block *sb = inode->i_sb;
1393 struct hlist_head *head = inode_hashtable + hash(sb, hashval);
1396 struct inode *old = NULL;
1398 spin_lock(&inode_hash_lock);
1399 hlist_for_each_entry(old, head, i_hash) {
1400 if (old->i_sb != sb)
1402 if (!test(old, data))
1404 spin_lock(&old->i_lock);
1405 if (old->i_state & (I_FREEING|I_WILL_FREE)) {
1406 spin_unlock(&old->i_lock);
1412 spin_lock(&inode->i_lock);
1413 inode->i_state |= I_NEW;
1414 hlist_add_head(&inode->i_hash, head);
1415 spin_unlock(&inode->i_lock);
1416 spin_unlock(&inode_hash_lock);
1420 spin_unlock(&old->i_lock);
1421 spin_unlock(&inode_hash_lock);
1423 if (unlikely(!inode_unhashed(old))) {
1430 EXPORT_SYMBOL(insert_inode_locked4);
1433 int generic_delete_inode(struct inode *inode)
1437 EXPORT_SYMBOL(generic_delete_inode);
1440 * Called when we're dropping the last reference
1443 * Call the FS "drop_inode()" function, defaulting to
1444 * the legacy UNIX filesystem behaviour. If it tells
1445 * us to evict inode, do so. Otherwise, retain inode
1446 * in cache if fs is alive, sync and evict if fs is
1449 static void iput_final(struct inode *inode)
1451 struct super_block *sb = inode->i_sb;
1452 const struct super_operations *op = inode->i_sb->s_op;
1455 WARN_ON(inode->i_state & I_NEW);
1458 drop = op->drop_inode(inode);
1460 drop = generic_drop_inode(inode);
1462 if (!drop && (sb->s_flags & MS_ACTIVE)) {
1463 inode->i_state |= I_REFERENCED;
1464 inode_add_lru(inode);
1465 spin_unlock(&inode->i_lock);
1470 inode->i_state |= I_WILL_FREE;
1471 spin_unlock(&inode->i_lock);
1472 write_inode_now(inode, 1);
1473 spin_lock(&inode->i_lock);
1474 WARN_ON(inode->i_state & I_NEW);
1475 inode->i_state &= ~I_WILL_FREE;
1478 inode->i_state |= I_FREEING;
1479 if (!list_empty(&inode->i_lru))
1480 inode_lru_list_del(inode);
1481 spin_unlock(&inode->i_lock);
1487 * iput - put an inode
1488 * @inode: inode to put
1490 * Puts an inode, dropping its usage count. If the inode use count hits
1491 * zero, the inode is then freed and may also be destroyed.
1493 * Consequently, iput() can sleep.
1495 void iput(struct inode *inode)
1499 BUG_ON(inode->i_state & I_CLEAR);
1501 if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {
1502 if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) {
1503 atomic_inc(&inode->i_count);
1504 inode->i_state &= ~I_DIRTY_TIME;
1505 spin_unlock(&inode->i_lock);
1506 trace_writeback_lazytime_iput(inode);
1507 mark_inode_dirty_sync(inode);
1513 EXPORT_SYMBOL(iput);
1516 * bmap - find a block number in a file
1517 * @inode: inode of file
1518 * @block: block to find
1520 * Returns the block number on the device holding the inode that
1521 * is the disk block number for the block of the file requested.
1522 * That is, asked for block 4 of inode 1 the function will return the
1523 * disk block relative to the disk start that holds that block of the
1526 sector_t bmap(struct inode *inode, sector_t block)
1529 if (inode->i_mapping->a_ops->bmap)
1530 res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
1533 EXPORT_SYMBOL(bmap);
1536 * With relative atime, only update atime if the previous atime is
1537 * earlier than either the ctime or mtime or if at least a day has
1538 * passed since the last atime update.
1540 static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
1541 struct timespec now)
1544 if (!(mnt->mnt_flags & MNT_RELATIME))
1547 * Is mtime younger than atime? If yes, update atime:
1549 if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
1552 * Is ctime younger than atime? If yes, update atime:
1554 if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
1558 * Is the previous atime value older than a day? If yes,
1561 if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
1564 * Good, we can skip the atime update:
1569 int generic_update_time(struct inode *inode, struct timespec *time, int flags)
1571 int iflags = I_DIRTY_TIME;
1573 if (flags & S_ATIME)
1574 inode->i_atime = *time;
1575 if (flags & S_VERSION)
1576 inode_inc_iversion(inode);
1577 if (flags & S_CTIME)
1578 inode->i_ctime = *time;
1579 if (flags & S_MTIME)
1580 inode->i_mtime = *time;
1582 if (!(inode->i_sb->s_flags & MS_LAZYTIME) || (flags & S_VERSION))
1583 iflags |= I_DIRTY_SYNC;
1584 __mark_inode_dirty(inode, iflags);
1587 EXPORT_SYMBOL(generic_update_time);
1590 * This does the actual work of updating an inodes time or version. Must have
1591 * had called mnt_want_write() before calling this.
1593 static int update_time(struct inode *inode, struct timespec *time, int flags)
1595 int (*update_time)(struct inode *, struct timespec *, int);
1597 update_time = inode->i_op->update_time ? inode->i_op->update_time :
1598 generic_update_time;
1600 return update_time(inode, time, flags);
1604 * touch_atime - update the access time
1605 * @path: the &struct path to update
1606 * @inode: inode to update
1608 * Update the accessed time on an inode and mark it for writeback.
1609 * This function automatically handles read only file systems and media,
1610 * as well as the "noatime" flag and inode specific "noatime" markers.
1612 bool atime_needs_update(const struct path *path, struct inode *inode)
1614 struct vfsmount *mnt = path->mnt;
1615 struct timespec now;
1617 if (inode->i_flags & S_NOATIME)
1619 if (IS_NOATIME(inode))
1621 if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
1624 if (mnt->mnt_flags & MNT_NOATIME)
1626 if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
1629 now = current_fs_time(inode->i_sb);
1631 if (!relatime_need_update(mnt, inode, now))
1634 if (timespec_equal(&inode->i_atime, &now))
1640 void touch_atime(const struct path *path)
1642 struct vfsmount *mnt = path->mnt;
1643 struct inode *inode = d_inode(path->dentry);
1644 struct timespec now;
1646 if (!atime_needs_update(path, inode))
1649 if (!sb_start_write_trylock(inode->i_sb))
1652 if (__mnt_want_write(mnt) != 0)
1655 * File systems can error out when updating inodes if they need to
1656 * allocate new space to modify an inode (such is the case for
1657 * Btrfs), but since we touch atime while walking down the path we
1658 * really don't care if we failed to update the atime of the file,
1659 * so just ignore the return value.
1660 * We may also fail on filesystems that have the ability to make parts
1661 * of the fs read only, e.g. subvolumes in Btrfs.
1663 now = current_fs_time(inode->i_sb);
1664 update_time(inode, &now, S_ATIME);
1665 __mnt_drop_write(mnt);
1667 sb_end_write(inode->i_sb);
1669 EXPORT_SYMBOL(touch_atime);
1672 * The logic we want is
1674 * if suid or (sgid and xgrp)
1677 int should_remove_suid(struct dentry *dentry)
1679 umode_t mode = d_inode(dentry)->i_mode;
1682 /* suid always must be killed */
1683 if (unlikely(mode & S_ISUID))
1684 kill = ATTR_KILL_SUID;
1687 * sgid without any exec bits is just a mandatory locking mark; leave
1688 * it alone. If some exec bits are set, it's a real sgid; kill it.
1690 if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1691 kill |= ATTR_KILL_SGID;
1693 if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode)))
1698 EXPORT_SYMBOL(should_remove_suid);
1701 * Return mask of changes for notify_change() that need to be done as a
1702 * response to write or truncate. Return 0 if nothing has to be changed.
1703 * Negative value on error (change should be denied).
1705 int dentry_needs_remove_privs(struct dentry *dentry)
1707 struct inode *inode = d_inode(dentry);
1711 if (IS_NOSEC(inode))
1714 mask = should_remove_suid(dentry);
1715 ret = security_inode_need_killpriv(dentry);
1719 mask |= ATTR_KILL_PRIV;
1722 EXPORT_SYMBOL(dentry_needs_remove_privs);
1724 static int __remove_privs(struct dentry *dentry, int kill)
1726 struct iattr newattrs;
1728 newattrs.ia_valid = ATTR_FORCE | kill;
1730 * Note we call this on write, so notify_change will not
1731 * encounter any conflicting delegations:
1733 return notify_change(dentry, &newattrs, NULL);
1737 * Remove special file priviledges (suid, capabilities) when file is written
1740 int file_remove_privs(struct file *file)
1742 struct dentry *dentry = file_dentry(file);
1743 struct inode *inode = file_inode(file);
1747 /* Fast path for nothing security related */
1748 if (IS_NOSEC(inode))
1751 kill = dentry_needs_remove_privs(dentry);
1755 error = __remove_privs(dentry, kill);
1757 inode_has_no_xattr(inode);
1761 EXPORT_SYMBOL(file_remove_privs);
1764 * file_update_time - update mtime and ctime time
1765 * @file: file accessed
1767 * Update the mtime and ctime members of an inode and mark the inode
1768 * for writeback. Note that this function is meant exclusively for
1769 * usage in the file write path of filesystems, and filesystems may
1770 * choose to explicitly ignore update via this function with the
1771 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1772 * timestamps are handled by the server. This can return an error for
1773 * file systems who need to allocate space in order to update an inode.
1776 int file_update_time(struct file *file)
1778 struct inode *inode = file_inode(file);
1779 struct timespec now;
1783 /* First try to exhaust all avenues to not sync */
1784 if (IS_NOCMTIME(inode))
1787 now = current_fs_time(inode->i_sb);
1788 if (!timespec_equal(&inode->i_mtime, &now))
1791 if (!timespec_equal(&inode->i_ctime, &now))
1794 if (IS_I_VERSION(inode))
1795 sync_it |= S_VERSION;
1800 /* Finally allowed to write? Takes lock. */
1801 if (__mnt_want_write_file(file))
1804 ret = update_time(inode, &now, sync_it);
1805 __mnt_drop_write_file(file);
1809 EXPORT_SYMBOL(file_update_time);
1811 int inode_needs_sync(struct inode *inode)
1815 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
1819 EXPORT_SYMBOL(inode_needs_sync);
1822 * If we try to find an inode in the inode hash while it is being
1823 * deleted, we have to wait until the filesystem completes its
1824 * deletion before reporting that it isn't found. This function waits
1825 * until the deletion _might_ have completed. Callers are responsible
1826 * to recheck inode state.
1828 * It doesn't matter if I_NEW is not set initially, a call to
1829 * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list
1832 static void __wait_on_freeing_inode(struct inode *inode)
1834 wait_queue_head_t *wq;
1835 DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
1836 wq = bit_waitqueue(&inode->i_state, __I_NEW);
1837 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
1838 spin_unlock(&inode->i_lock);
1839 spin_unlock(&inode_hash_lock);
1841 finish_wait(wq, &wait.wait);
1842 spin_lock(&inode_hash_lock);
1845 static __initdata unsigned long ihash_entries;
1846 static int __init set_ihash_entries(char *str)
1850 ihash_entries = simple_strtoul(str, &str, 0);
1853 __setup("ihash_entries=", set_ihash_entries);
1856 * Initialize the waitqueues and inode hash table.
1858 void __init inode_init_early(void)
1862 /* If hashes are distributed across NUMA nodes, defer
1863 * hash allocation until vmalloc space is available.
1869 alloc_large_system_hash("Inode-cache",
1870 sizeof(struct hlist_head),
1879 for (loop = 0; loop < (1U << i_hash_shift); loop++)
1880 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1883 void __init inode_init(void)
1887 /* inode slab cache */
1888 inode_cachep = kmem_cache_create("inode_cache",
1889 sizeof(struct inode),
1891 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
1895 /* Hash may have been set up in inode_init_early */
1900 alloc_large_system_hash("Inode-cache",
1901 sizeof(struct hlist_head),
1910 for (loop = 0; loop < (1U << i_hash_shift); loop++)
1911 INIT_HLIST_HEAD(&inode_hashtable[loop]);
1914 void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
1916 inode->i_mode = mode;
1917 if (S_ISCHR(mode)) {
1918 inode->i_fop = &def_chr_fops;
1919 inode->i_rdev = rdev;
1920 } else if (S_ISBLK(mode)) {
1921 inode->i_fop = &def_blk_fops;
1922 inode->i_rdev = rdev;
1923 } else if (S_ISFIFO(mode))
1924 inode->i_fop = &pipefifo_fops;
1925 else if (S_ISSOCK(mode))
1926 ; /* leave it no_open_fops */
1928 printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
1929 " inode %s:%lu\n", mode, inode->i_sb->s_id,
1932 EXPORT_SYMBOL(init_special_inode);
1935 * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
1937 * @dir: Directory inode
1938 * @mode: mode of the new inode
1940 void inode_init_owner(struct inode *inode, const struct inode *dir,
1943 inode->i_uid = current_fsuid();
1944 if (dir && dir->i_mode & S_ISGID) {
1945 inode->i_gid = dir->i_gid;
1949 inode->i_gid = current_fsgid();
1950 inode->i_mode = mode;
1952 EXPORT_SYMBOL(inode_init_owner);
1955 * inode_owner_or_capable - check current task permissions to inode
1956 * @inode: inode being checked
1958 * Return true if current either has CAP_FOWNER in a namespace with the
1959 * inode owner uid mapped, or owns the file.
1961 bool inode_owner_or_capable(const struct inode *inode)
1963 struct user_namespace *ns;
1965 if (uid_eq(current_fsuid(), inode->i_uid))
1968 ns = current_user_ns();
1969 if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid))
1973 EXPORT_SYMBOL(inode_owner_or_capable);
1976 * Direct i/o helper functions
1978 static void __inode_dio_wait(struct inode *inode)
1980 wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
1981 DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
1984 prepare_to_wait(wq, &q.wait, TASK_UNINTERRUPTIBLE);
1985 if (atomic_read(&inode->i_dio_count))
1987 } while (atomic_read(&inode->i_dio_count));
1988 finish_wait(wq, &q.wait);
1992 * inode_dio_wait - wait for outstanding DIO requests to finish
1993 * @inode: inode to wait for
1995 * Waits for all pending direct I/O requests to finish so that we can
1996 * proceed with a truncate or equivalent operation.
1998 * Must be called under a lock that serializes taking new references
1999 * to i_dio_count, usually by inode->i_mutex.
2001 void inode_dio_wait(struct inode *inode)
2003 if (atomic_read(&inode->i_dio_count))
2004 __inode_dio_wait(inode);
2006 EXPORT_SYMBOL(inode_dio_wait);
2009 * inode_set_flags - atomically set some inode flags
2011 * Note: the caller should be holding i_mutex, or else be sure that
2012 * they have exclusive access to the inode structure (i.e., while the
2013 * inode is being instantiated). The reason for the cmpxchg() loop
2014 * --- which wouldn't be necessary if all code paths which modify
2015 * i_flags actually followed this rule, is that there is at least one
2016 * code path which doesn't today so we use cmpxchg() out of an abundance
2019 * In the long run, i_mutex is overkill, and we should probably look
2020 * at using the i_lock spinlock to protect i_flags, and then make sure
2021 * it is so documented in include/linux/fs.h and that all code follows
2022 * the locking convention!!
2024 void inode_set_flags(struct inode *inode, unsigned int flags,
2027 unsigned int old_flags, new_flags;
2029 WARN_ON_ONCE(flags & ~mask);
2031 old_flags = ACCESS_ONCE(inode->i_flags);
2032 new_flags = (old_flags & ~mask) | flags;
2033 } while (unlikely(cmpxchg(&inode->i_flags, old_flags,
2034 new_flags) != old_flags));
2036 EXPORT_SYMBOL(inode_set_flags);