4 * (C) 1997 Linus Torvalds
9 #include <linux/dcache.h>
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <linux/writeback.h>
13 #include <linux/module.h>
14 #include <linux/backing-dev.h>
15 #include <linux/wait.h>
16 #include <linux/rwsem.h>
17 #include <linux/hash.h>
18 #include <linux/swap.h>
19 #include <linux/security.h>
20 #include <linux/pagemap.h>
21 #include <linux/cdev.h>
22 #include <linux/bootmem.h>
23 #include <linux/inotify.h>
24 #include <linux/fsnotify.h>
25 #include <linux/mount.h>
26 #include <linux/async.h>
27 #include <linux/posix_acl.h>
30 * This is needed for the following functions:
32 * - invalidate_inode_buffers
35 * FIXME: remove all knowledge of the buffer layer from this file
37 #include <linux/buffer_head.h>
40 * New inode.c implementation.
42 * This implementation has the basic premise of trying
43 * to be extremely low-overhead and SMP-safe, yet be
44 * simple enough to be "obviously correct".
49 /* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
51 /* #define INODE_PARANOIA 1 */
52 /* #define INODE_DEBUG 1 */
55 * Inode lookup is no longer as critical as it used to be:
56 * most of the lookups are going to be through the dcache.
58 #define I_HASHBITS i_hash_shift
59 #define I_HASHMASK i_hash_mask
61 static unsigned int i_hash_mask __read_mostly
;
62 static unsigned int i_hash_shift __read_mostly
;
65 * Each inode can be on two separate lists. One is
66 * the hash list of the inode, used for lookups. The
67 * other linked list is the "type" list:
68 * "in_use" - valid inode, i_count > 0, i_nlink > 0
69 * "dirty" - as "in_use" but also dirty
70 * "unused" - valid inode, i_count = 0
72 * A "dirty" list is maintained for each super block,
73 * allowing for low-overhead inode sync() operations.
76 LIST_HEAD(inode_in_use
);
77 LIST_HEAD(inode_unused
);
78 static struct hlist_head
*inode_hashtable __read_mostly
;
81 * A simple spinlock to protect the list manipulations.
83 * NOTE! You also have to own the lock if you change
84 * the i_state of an inode while it is in use..
86 DEFINE_SPINLOCK(inode_lock
);
89 * iprune_sem provides exclusion between the kswapd or try_to_free_pages
90 * icache shrinking path, and the umount path. Without this exclusion,
91 * by the time prune_icache calls iput for the inode whose pages it has
92 * been invalidating, or by the time it calls clear_inode & destroy_inode
93 * from its final dispose_list, the struct super_block they refer to
94 * (for inode->i_sb->s_op) may already have been freed and reused.
96 * We make this an rwsem because the fastpath is icache shrinking. In
97 * some cases a filesystem may be doing a significant amount of work in
98 * its inode reclaim code, so this should improve parallelism.
100 static DECLARE_RWSEM(iprune_sem
);
103 * Statistics gathering..
105 struct inodes_stat_t inodes_stat
;
107 static struct kmem_cache
*inode_cachep __read_mostly
;
109 static void wake_up_inode(struct inode
*inode
)
112 * Prevent speculative execution through spin_unlock(&inode_lock);
115 wake_up_bit(&inode
->i_state
, __I_NEW
);
119 * inode_init_always - perform inode structure intialisation
120 * @sb: superblock inode belongs to
121 * @inode: inode to initialise
123 * These are initializations that need to be done on every inode
124 * allocation as the fields are not initialised by slab allocation.
126 int inode_init_always(struct super_block
*sb
, struct inode
*inode
)
128 static const struct address_space_operations empty_aops
;
129 static const struct inode_operations empty_iops
;
130 static const struct file_operations empty_fops
;
131 struct address_space
*const mapping
= &inode
->i_data
;
134 inode
->i_blkbits
= sb
->s_blocksize_bits
;
136 atomic_set(&inode
->i_count
, 1);
137 inode
->i_op
= &empty_iops
;
138 inode
->i_fop
= &empty_fops
;
142 atomic_set(&inode
->i_writecount
, 0);
146 inode
->i_generation
= 0;
148 memset(&inode
->i_dquot
, 0, sizeof(inode
->i_dquot
));
150 inode
->i_pipe
= NULL
;
151 inode
->i_bdev
= NULL
;
152 inode
->i_cdev
= NULL
;
154 inode
->dirtied_when
= 0;
156 if (security_inode_alloc(inode
))
158 spin_lock_init(&inode
->i_lock
);
159 lockdep_set_class(&inode
->i_lock
, &sb
->s_type
->i_lock_key
);
161 mutex_init(&inode
->i_mutex
);
162 lockdep_set_class(&inode
->i_mutex
, &sb
->s_type
->i_mutex_key
);
164 init_rwsem(&inode
->i_alloc_sem
);
165 lockdep_set_class(&inode
->i_alloc_sem
, &sb
->s_type
->i_alloc_sem_key
);
167 mapping
->a_ops
= &empty_aops
;
168 mapping
->host
= inode
;
170 mapping_set_gfp_mask(mapping
, GFP_HIGHUSER_MOVABLE
);
171 mapping
->assoc_mapping
= NULL
;
172 mapping
->backing_dev_info
= &default_backing_dev_info
;
173 mapping
->writeback_index
= 0;
176 * If the block_device provides a backing_dev_info for client
177 * inodes then use that. Otherwise the inode share the bdev's
181 struct backing_dev_info
*bdi
;
183 bdi
= sb
->s_bdev
->bd_inode
->i_mapping
->backing_dev_info
;
184 mapping
->backing_dev_info
= bdi
;
186 inode
->i_private
= NULL
;
187 inode
->i_mapping
= mapping
;
188 #ifdef CONFIG_FS_POSIX_ACL
189 inode
->i_acl
= inode
->i_default_acl
= ACL_NOT_CACHED
;
192 #ifdef CONFIG_FSNOTIFY
193 inode
->i_fsnotify_mask
= 0;
200 EXPORT_SYMBOL(inode_init_always
);
202 static struct inode
*alloc_inode(struct super_block
*sb
)
206 if (sb
->s_op
->alloc_inode
)
207 inode
= sb
->s_op
->alloc_inode(sb
);
209 inode
= kmem_cache_alloc(inode_cachep
, GFP_KERNEL
);
214 if (unlikely(inode_init_always(sb
, inode
))) {
215 if (inode
->i_sb
->s_op
->destroy_inode
)
216 inode
->i_sb
->s_op
->destroy_inode(inode
);
218 kmem_cache_free(inode_cachep
, inode
);
225 void __destroy_inode(struct inode
*inode
)
227 BUG_ON(inode_has_buffers(inode
));
228 security_inode_free(inode
);
229 fsnotify_inode_delete(inode
);
230 #ifdef CONFIG_FS_POSIX_ACL
231 if (inode
->i_acl
&& inode
->i_acl
!= ACL_NOT_CACHED
)
232 posix_acl_release(inode
->i_acl
);
233 if (inode
->i_default_acl
&& inode
->i_default_acl
!= ACL_NOT_CACHED
)
234 posix_acl_release(inode
->i_default_acl
);
237 EXPORT_SYMBOL(__destroy_inode
);
239 void destroy_inode(struct inode
*inode
)
241 __destroy_inode(inode
);
242 if (inode
->i_sb
->s_op
->destroy_inode
)
243 inode
->i_sb
->s_op
->destroy_inode(inode
);
245 kmem_cache_free(inode_cachep
, (inode
));
249 * These are initializations that only need to be done
250 * once, because the fields are idempotent across use
251 * of the inode, so let the slab aware of that.
253 void inode_init_once(struct inode
*inode
)
255 memset(inode
, 0, sizeof(*inode
));
256 INIT_HLIST_NODE(&inode
->i_hash
);
257 INIT_LIST_HEAD(&inode
->i_dentry
);
258 INIT_LIST_HEAD(&inode
->i_devices
);
259 INIT_RADIX_TREE(&inode
->i_data
.page_tree
, GFP_ATOMIC
);
260 spin_lock_init(&inode
->i_data
.tree_lock
);
261 spin_lock_init(&inode
->i_data
.i_mmap_lock
);
262 INIT_LIST_HEAD(&inode
->i_data
.private_list
);
263 spin_lock_init(&inode
->i_data
.private_lock
);
264 INIT_RAW_PRIO_TREE_ROOT(&inode
->i_data
.i_mmap
);
265 INIT_LIST_HEAD(&inode
->i_data
.i_mmap_nonlinear
);
266 i_size_ordered_init(inode
);
267 #ifdef CONFIG_INOTIFY
268 INIT_LIST_HEAD(&inode
->inotify_watches
);
269 mutex_init(&inode
->inotify_mutex
);
271 #ifdef CONFIG_FSNOTIFY
272 INIT_HLIST_HEAD(&inode
->i_fsnotify_mark_entries
);
275 EXPORT_SYMBOL(inode_init_once
);
277 static void init_once(void *foo
)
279 struct inode
*inode
= (struct inode
*) foo
;
281 inode_init_once(inode
);
285 * inode_lock must be held
287 void __iget(struct inode
*inode
)
289 if (atomic_inc_return(&inode
->i_count
) != 1)
292 if (!(inode
->i_state
& (I_DIRTY
|I_SYNC
)))
293 list_move(&inode
->i_list
, &inode_in_use
);
294 inodes_stat
.nr_unused
--;
298 * clear_inode - clear an inode
299 * @inode: inode to clear
301 * This is called by the filesystem to tell us
302 * that the inode is no longer useful. We just
303 * terminate it with extreme prejudice.
305 void clear_inode(struct inode
*inode
)
308 invalidate_inode_buffers(inode
);
310 BUG_ON(inode
->i_data
.nrpages
);
311 BUG_ON(!(inode
->i_state
& I_FREEING
));
312 BUG_ON(inode
->i_state
& I_CLEAR
);
313 inode_sync_wait(inode
);
314 if (inode
->i_sb
->s_op
->clear_inode
)
315 inode
->i_sb
->s_op
->clear_inode(inode
);
316 inode
->i_state
= I_FREEING
| I_CLEAR
;
318 EXPORT_SYMBOL(clear_inode
);
320 static void evict(struct inode
*inode
, int delete)
322 const struct super_operations
*op
= inode
->i_sb
->s_op
;
324 if (op
->evict_inode
) {
325 op
->evict_inode(inode
);
326 } else if (delete && op
->delete_inode
) {
327 op
->delete_inode(inode
);
329 if (inode
->i_data
.nrpages
)
330 truncate_inode_pages(&inode
->i_data
, 0);
333 if (S_ISBLK(inode
->i_mode
) && inode
->i_bdev
)
335 if (S_ISCHR(inode
->i_mode
) && inode
->i_cdev
)
340 * dispose_list - dispose of the contents of a local list
341 * @head: the head of the list to free
343 * Dispose-list gets a local list with local inodes in it, so it doesn't
344 * need to worry about list corruption and SMP locks.
346 static void dispose_list(struct list_head
*head
)
350 while (!list_empty(head
)) {
353 inode
= list_first_entry(head
, struct inode
, i_list
);
354 list_del(&inode
->i_list
);
358 spin_lock(&inode_lock
);
359 hlist_del_init(&inode
->i_hash
);
360 list_del_init(&inode
->i_sb_list
);
361 spin_unlock(&inode_lock
);
363 wake_up_inode(inode
);
364 destroy_inode(inode
);
367 spin_lock(&inode_lock
);
368 inodes_stat
.nr_inodes
-= nr_disposed
;
369 spin_unlock(&inode_lock
);
373 * Invalidate all inodes for a device.
375 static int invalidate_list(struct list_head
*head
, struct list_head
*dispose
)
377 struct list_head
*next
;
378 int busy
= 0, count
= 0;
382 struct list_head
*tmp
= next
;
386 * We can reschedule here without worrying about the list's
387 * consistency because the per-sb list of inodes must not
388 * change during umount anymore, and because iprune_sem keeps
389 * shrink_icache_memory() away.
391 cond_resched_lock(&inode_lock
);
396 inode
= list_entry(tmp
, struct inode
, i_sb_list
);
397 if (inode
->i_state
& I_NEW
)
399 invalidate_inode_buffers(inode
);
400 if (!atomic_read(&inode
->i_count
)) {
401 list_move(&inode
->i_list
, dispose
);
402 WARN_ON(inode
->i_state
& I_NEW
);
403 inode
->i_state
|= I_FREEING
;
409 /* only unused inodes may be cached with i_count zero */
410 inodes_stat
.nr_unused
-= count
;
415 * invalidate_inodes - discard the inodes on a device
418 * Discard all of the inodes for a given superblock. If the discard
419 * fails because there are busy inodes then a non zero value is returned.
420 * If the discard is successful all the inodes have been discarded.
422 int invalidate_inodes(struct super_block
*sb
)
425 LIST_HEAD(throw_away
);
427 down_write(&iprune_sem
);
428 spin_lock(&inode_lock
);
429 inotify_unmount_inodes(&sb
->s_inodes
);
430 fsnotify_unmount_inodes(&sb
->s_inodes
);
431 busy
= invalidate_list(&sb
->s_inodes
, &throw_away
);
432 spin_unlock(&inode_lock
);
434 dispose_list(&throw_away
);
435 up_write(&iprune_sem
);
439 EXPORT_SYMBOL(invalidate_inodes
);
441 static int can_unuse(struct inode
*inode
)
445 if (inode_has_buffers(inode
))
447 if (atomic_read(&inode
->i_count
))
449 if (inode
->i_data
.nrpages
)
455 * Scan `goal' inodes on the unused list for freeable ones. They are moved to
456 * a temporary list and then are freed outside inode_lock by dispose_list().
458 * Any inodes which are pinned purely because of attached pagecache have their
459 * pagecache removed. We expect the final iput() on that inode to add it to
460 * the front of the inode_unused list. So look for it there and if the
461 * inode is still freeable, proceed. The right inode is found 99.9% of the
462 * time in testing on a 4-way.
464 * If the inode has metadata buffers attached to mapping->private_list then
465 * try to remove them.
467 static void prune_icache(int nr_to_scan
)
472 unsigned long reap
= 0;
474 down_read(&iprune_sem
);
475 spin_lock(&inode_lock
);
476 for (nr_scanned
= 0; nr_scanned
< nr_to_scan
; nr_scanned
++) {
479 if (list_empty(&inode_unused
))
482 inode
= list_entry(inode_unused
.prev
, struct inode
, i_list
);
484 if (inode
->i_state
|| atomic_read(&inode
->i_count
)) {
485 list_move(&inode
->i_list
, &inode_unused
);
488 if (inode_has_buffers(inode
) || inode
->i_data
.nrpages
) {
490 spin_unlock(&inode_lock
);
491 if (remove_inode_buffers(inode
))
492 reap
+= invalidate_mapping_pages(&inode
->i_data
,
495 spin_lock(&inode_lock
);
497 if (inode
!= list_entry(inode_unused
.next
,
498 struct inode
, i_list
))
499 continue; /* wrong inode or list_empty */
500 if (!can_unuse(inode
))
503 list_move(&inode
->i_list
, &freeable
);
504 WARN_ON(inode
->i_state
& I_NEW
);
505 inode
->i_state
|= I_FREEING
;
508 inodes_stat
.nr_unused
-= nr_pruned
;
509 if (current_is_kswapd())
510 __count_vm_events(KSWAPD_INODESTEAL
, reap
);
512 __count_vm_events(PGINODESTEAL
, reap
);
513 spin_unlock(&inode_lock
);
515 dispose_list(&freeable
);
516 up_read(&iprune_sem
);
520 * shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
521 * "unused" means that no dentries are referring to the inodes: the files are
522 * not open and the dcache references to those inodes have already been
525 * This function is passed the number of inodes to scan, and it returns the
526 * total number of remaining possibly-reclaimable inodes.
528 static int shrink_icache_memory(struct shrinker
*shrink
, int nr
, gfp_t gfp_mask
)
532 * Nasty deadlock avoidance. We may hold various FS locks,
533 * and we don't want to recurse into the FS that called us
534 * in clear_inode() and friends..
536 if (!(gfp_mask
& __GFP_FS
))
540 return (inodes_stat
.nr_unused
/ 100) * sysctl_vfs_cache_pressure
;
543 static struct shrinker icache_shrinker
= {
544 .shrink
= shrink_icache_memory
,
545 .seeks
= DEFAULT_SEEKS
,
548 static void __wait_on_freeing_inode(struct inode
*inode
);
550 * Called with the inode lock held.
551 * NOTE: we are not increasing the inode-refcount, you must call __iget()
552 * by hand after calling find_inode now! This simplifies iunique and won't
553 * add any additional branch in the common code.
555 static struct inode
*find_inode(struct super_block
*sb
,
556 struct hlist_head
*head
,
557 int (*test
)(struct inode
*, void *),
560 struct hlist_node
*node
;
561 struct inode
*inode
= NULL
;
564 hlist_for_each_entry(inode
, node
, head
, i_hash
) {
565 if (inode
->i_sb
!= sb
)
567 if (!test(inode
, data
))
569 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
570 __wait_on_freeing_inode(inode
);
575 return node
? inode
: NULL
;
579 * find_inode_fast is the fast path version of find_inode, see the comment at
580 * iget_locked for details.
582 static struct inode
*find_inode_fast(struct super_block
*sb
,
583 struct hlist_head
*head
, unsigned long ino
)
585 struct hlist_node
*node
;
586 struct inode
*inode
= NULL
;
589 hlist_for_each_entry(inode
, node
, head
, i_hash
) {
590 if (inode
->i_ino
!= ino
)
592 if (inode
->i_sb
!= sb
)
594 if (inode
->i_state
& (I_FREEING
|I_WILL_FREE
)) {
595 __wait_on_freeing_inode(inode
);
600 return node
? inode
: NULL
;
603 static unsigned long hash(struct super_block
*sb
, unsigned long hashval
)
607 tmp
= (hashval
* (unsigned long)sb
) ^ (GOLDEN_RATIO_PRIME
+ hashval
) /
609 tmp
= tmp
^ ((tmp
^ GOLDEN_RATIO_PRIME
) >> I_HASHBITS
);
610 return tmp
& I_HASHMASK
;
614 __inode_add_to_lists(struct super_block
*sb
, struct hlist_head
*head
,
617 inodes_stat
.nr_inodes
++;
618 list_add(&inode
->i_list
, &inode_in_use
);
619 list_add(&inode
->i_sb_list
, &sb
->s_inodes
);
621 hlist_add_head(&inode
->i_hash
, head
);
625 * inode_add_to_lists - add a new inode to relevant lists
626 * @sb: superblock inode belongs to
627 * @inode: inode to mark in use
629 * When an inode is allocated it needs to be accounted for, added to the in use
630 * list, the owning superblock and the inode hash. This needs to be done under
631 * the inode_lock, so export a function to do this rather than the inode lock
632 * itself. We calculate the hash list to add to here so it is all internal
633 * which requires the caller to have already set up the inode number in the
636 void inode_add_to_lists(struct super_block
*sb
, struct inode
*inode
)
638 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, inode
->i_ino
);
640 spin_lock(&inode_lock
);
641 __inode_add_to_lists(sb
, head
, inode
);
642 spin_unlock(&inode_lock
);
644 EXPORT_SYMBOL_GPL(inode_add_to_lists
);
647 * new_inode - obtain an inode
650 * Allocates a new inode for given superblock. The default gfp_mask
651 * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
652 * If HIGHMEM pages are unsuitable or it is known that pages allocated
653 * for the page cache are not reclaimable or migratable,
654 * mapping_set_gfp_mask() must be called with suitable flags on the
655 * newly created inode's mapping
658 struct inode
*new_inode(struct super_block
*sb
)
661 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
662 * error if st_ino won't fit in target struct field. Use 32bit counter
663 * here to attempt to avoid that.
665 static unsigned int last_ino
;
668 spin_lock_prefetch(&inode_lock
);
670 inode
= alloc_inode(sb
);
672 spin_lock(&inode_lock
);
673 __inode_add_to_lists(sb
, NULL
, inode
);
674 inode
->i_ino
= ++last_ino
;
676 spin_unlock(&inode_lock
);
680 EXPORT_SYMBOL(new_inode
);
682 void unlock_new_inode(struct inode
*inode
)
684 #ifdef CONFIG_DEBUG_LOCK_ALLOC
685 if (inode
->i_mode
& S_IFDIR
) {
686 struct file_system_type
*type
= inode
->i_sb
->s_type
;
688 /* Set new key only if filesystem hasn't already changed it */
689 if (!lockdep_match_class(&inode
->i_mutex
,
690 &type
->i_mutex_key
)) {
692 * ensure nobody is actually holding i_mutex
694 mutex_destroy(&inode
->i_mutex
);
695 mutex_init(&inode
->i_mutex
);
696 lockdep_set_class(&inode
->i_mutex
,
697 &type
->i_mutex_dir_key
);
702 * This is special! We do not need the spinlock when clearing I_NEW,
703 * because we're guaranteed that nobody else tries to do anything about
704 * the state of the inode when it is locked, as we just created it (so
705 * there can be no old holders that haven't tested I_NEW).
706 * However we must emit the memory barrier so that other CPUs reliably
707 * see the clearing of I_NEW after the other inode initialisation has
711 WARN_ON(!(inode
->i_state
& I_NEW
));
712 inode
->i_state
&= ~I_NEW
;
713 wake_up_inode(inode
);
715 EXPORT_SYMBOL(unlock_new_inode
);
718 * This is called without the inode lock held.. Be careful.
720 * We no longer cache the sb_flags in i_flags - see fs.h
721 * -- rmk@arm.uk.linux.org
723 static struct inode
*get_new_inode(struct super_block
*sb
,
724 struct hlist_head
*head
,
725 int (*test
)(struct inode
*, void *),
726 int (*set
)(struct inode
*, void *),
731 inode
= alloc_inode(sb
);
735 spin_lock(&inode_lock
);
736 /* We released the lock, so.. */
737 old
= find_inode(sb
, head
, test
, data
);
739 if (set(inode
, data
))
742 __inode_add_to_lists(sb
, head
, inode
);
743 inode
->i_state
= I_NEW
;
744 spin_unlock(&inode_lock
);
746 /* Return the locked inode with I_NEW set, the
747 * caller is responsible for filling in the contents
753 * Uhhuh, somebody else created the same inode under
754 * us. Use the old inode instead of the one we just
758 spin_unlock(&inode_lock
);
759 destroy_inode(inode
);
761 wait_on_inode(inode
);
766 spin_unlock(&inode_lock
);
767 destroy_inode(inode
);
772 * get_new_inode_fast is the fast path version of get_new_inode, see the
773 * comment at iget_locked for details.
775 static struct inode
*get_new_inode_fast(struct super_block
*sb
,
776 struct hlist_head
*head
, unsigned long ino
)
780 inode
= alloc_inode(sb
);
784 spin_lock(&inode_lock
);
785 /* We released the lock, so.. */
786 old
= find_inode_fast(sb
, head
, ino
);
789 __inode_add_to_lists(sb
, head
, inode
);
790 inode
->i_state
= I_NEW
;
791 spin_unlock(&inode_lock
);
793 /* Return the locked inode with I_NEW set, the
794 * caller is responsible for filling in the contents
800 * Uhhuh, somebody else created the same inode under
801 * us. Use the old inode instead of the one we just
805 spin_unlock(&inode_lock
);
806 destroy_inode(inode
);
808 wait_on_inode(inode
);
814 * iunique - get a unique inode number
816 * @max_reserved: highest reserved inode number
818 * Obtain an inode number that is unique on the system for a given
819 * superblock. This is used by file systems that have no natural
820 * permanent inode numbering system. An inode number is returned that
821 * is higher than the reserved limit but unique.
824 * With a large number of inodes live on the file system this function
825 * currently becomes quite slow.
827 ino_t
iunique(struct super_block
*sb
, ino_t max_reserved
)
830 * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
831 * error if st_ino won't fit in target struct field. Use 32bit counter
832 * here to attempt to avoid that.
834 static unsigned int counter
;
836 struct hlist_head
*head
;
839 spin_lock(&inode_lock
);
841 if (counter
<= max_reserved
)
842 counter
= max_reserved
+ 1;
844 head
= inode_hashtable
+ hash(sb
, res
);
845 inode
= find_inode_fast(sb
, head
, res
);
846 } while (inode
!= NULL
);
847 spin_unlock(&inode_lock
);
851 EXPORT_SYMBOL(iunique
);
853 struct inode
*igrab(struct inode
*inode
)
855 spin_lock(&inode_lock
);
856 if (!(inode
->i_state
& (I_FREEING
|I_WILL_FREE
)))
860 * Handle the case where s_op->clear_inode is not been
861 * called yet, and somebody is calling igrab
862 * while the inode is getting freed.
865 spin_unlock(&inode_lock
);
868 EXPORT_SYMBOL(igrab
);
871 * ifind - internal function, you want ilookup5() or iget5().
872 * @sb: super block of file system to search
873 * @head: the head of the list to search
874 * @test: callback used for comparisons between inodes
875 * @data: opaque data pointer to pass to @test
876 * @wait: if true wait for the inode to be unlocked, if false do not
878 * ifind() searches for the inode specified by @data in the inode
879 * cache. This is a generalized version of ifind_fast() for file systems where
880 * the inode number is not sufficient for unique identification of an inode.
882 * If the inode is in the cache, the inode is returned with an incremented
885 * Otherwise NULL is returned.
887 * Note, @test is called with the inode_lock held, so can't sleep.
889 static struct inode
*ifind(struct super_block
*sb
,
890 struct hlist_head
*head
, int (*test
)(struct inode
*, void *),
891 void *data
, const int wait
)
895 spin_lock(&inode_lock
);
896 inode
= find_inode(sb
, head
, test
, data
);
899 spin_unlock(&inode_lock
);
901 wait_on_inode(inode
);
904 spin_unlock(&inode_lock
);
909 * ifind_fast - internal function, you want ilookup() or iget().
910 * @sb: super block of file system to search
911 * @head: head of the list to search
912 * @ino: inode number to search for
914 * ifind_fast() searches for the inode @ino in the inode cache. This is for
915 * file systems where the inode number is sufficient for unique identification
918 * If the inode is in the cache, the inode is returned with an incremented
921 * Otherwise NULL is returned.
923 static struct inode
*ifind_fast(struct super_block
*sb
,
924 struct hlist_head
*head
, unsigned long ino
)
928 spin_lock(&inode_lock
);
929 inode
= find_inode_fast(sb
, head
, ino
);
932 spin_unlock(&inode_lock
);
933 wait_on_inode(inode
);
936 spin_unlock(&inode_lock
);
941 * ilookup5_nowait - search for an inode in the inode cache
942 * @sb: super block of file system to search
943 * @hashval: hash value (usually inode number) to search for
944 * @test: callback used for comparisons between inodes
945 * @data: opaque data pointer to pass to @test
947 * ilookup5() uses ifind() to search for the inode specified by @hashval and
948 * @data in the inode cache. This is a generalized version of ilookup() for
949 * file systems where the inode number is not sufficient for unique
950 * identification of an inode.
952 * If the inode is in the cache, the inode is returned with an incremented
953 * reference count. Note, the inode lock is not waited upon so you have to be
954 * very careful what you do with the returned inode. You probably should be
955 * using ilookup5() instead.
957 * Otherwise NULL is returned.
959 * Note, @test is called with the inode_lock held, so can't sleep.
961 struct inode
*ilookup5_nowait(struct super_block
*sb
, unsigned long hashval
,
962 int (*test
)(struct inode
*, void *), void *data
)
964 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
966 return ifind(sb
, head
, test
, data
, 0);
968 EXPORT_SYMBOL(ilookup5_nowait
);
971 * ilookup5 - search for an inode in the inode cache
972 * @sb: super block of file system to search
973 * @hashval: hash value (usually inode number) to search for
974 * @test: callback used for comparisons between inodes
975 * @data: opaque data pointer to pass to @test
977 * ilookup5() uses ifind() to search for the inode specified by @hashval and
978 * @data in the inode cache. This is a generalized version of ilookup() for
979 * file systems where the inode number is not sufficient for unique
980 * identification of an inode.
982 * If the inode is in the cache, the inode lock is waited upon and the inode is
983 * returned with an incremented reference count.
985 * Otherwise NULL is returned.
987 * Note, @test is called with the inode_lock held, so can't sleep.
989 struct inode
*ilookup5(struct super_block
*sb
, unsigned long hashval
,
990 int (*test
)(struct inode
*, void *), void *data
)
992 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
994 return ifind(sb
, head
, test
, data
, 1);
996 EXPORT_SYMBOL(ilookup5
);
999 * ilookup - search for an inode in the inode cache
1000 * @sb: super block of file system to search
1001 * @ino: inode number to search for
1003 * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
1004 * This is for file systems where the inode number is sufficient for unique
1005 * identification of an inode.
1007 * If the inode is in the cache, the inode is returned with an incremented
1010 * Otherwise NULL is returned.
1012 struct inode
*ilookup(struct super_block
*sb
, unsigned long ino
)
1014 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1016 return ifind_fast(sb
, head
, ino
);
1018 EXPORT_SYMBOL(ilookup
);
1021 * iget5_locked - obtain an inode from a mounted file system
1022 * @sb: super block of file system
1023 * @hashval: hash value (usually inode number) to get
1024 * @test: callback used for comparisons between inodes
1025 * @set: callback used to initialize a new struct inode
1026 * @data: opaque data pointer to pass to @test and @set
1028 * iget5_locked() uses ifind() to search for the inode specified by @hashval
1029 * and @data in the inode cache and if present it is returned with an increased
1030 * reference count. This is a generalized version of iget_locked() for file
1031 * systems where the inode number is not sufficient for unique identification
1034 * If the inode is not in cache, get_new_inode() is called to allocate a new
1035 * inode and this is returned locked, hashed, and with the I_NEW flag set. The
1036 * file system gets to fill it in before unlocking it via unlock_new_inode().
1038 * Note both @test and @set are called with the inode_lock held, so can't sleep.
1040 struct inode
*iget5_locked(struct super_block
*sb
, unsigned long hashval
,
1041 int (*test
)(struct inode
*, void *),
1042 int (*set
)(struct inode
*, void *), void *data
)
1044 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1045 struct inode
*inode
;
1047 inode
= ifind(sb
, head
, test
, data
, 1);
1051 * get_new_inode() will do the right thing, re-trying the search
1052 * in case it had to block at any point.
1054 return get_new_inode(sb
, head
, test
, set
, data
);
1056 EXPORT_SYMBOL(iget5_locked
);
1059 * iget_locked - obtain an inode from a mounted file system
1060 * @sb: super block of file system
1061 * @ino: inode number to get
1063 * iget_locked() uses ifind_fast() to search for the inode specified by @ino in
1064 * the inode cache and if present it is returned with an increased reference
1065 * count. This is for file systems where the inode number is sufficient for
1066 * unique identification of an inode.
1068 * If the inode is not in cache, get_new_inode_fast() is called to allocate a
1069 * new inode and this is returned locked, hashed, and with the I_NEW flag set.
1070 * The file system gets to fill it in before unlocking it via
1071 * unlock_new_inode().
1073 struct inode
*iget_locked(struct super_block
*sb
, unsigned long ino
)
1075 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1076 struct inode
*inode
;
1078 inode
= ifind_fast(sb
, head
, ino
);
1082 * get_new_inode_fast() will do the right thing, re-trying the search
1083 * in case it had to block at any point.
1085 return get_new_inode_fast(sb
, head
, ino
);
1087 EXPORT_SYMBOL(iget_locked
);
1089 int insert_inode_locked(struct inode
*inode
)
1091 struct super_block
*sb
= inode
->i_sb
;
1092 ino_t ino
= inode
->i_ino
;
1093 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, ino
);
1095 inode
->i_state
|= I_NEW
;
1097 struct hlist_node
*node
;
1098 struct inode
*old
= NULL
;
1099 spin_lock(&inode_lock
);
1100 hlist_for_each_entry(old
, node
, head
, i_hash
) {
1101 if (old
->i_ino
!= ino
)
1103 if (old
->i_sb
!= sb
)
1105 if (old
->i_state
& (I_FREEING
|I_WILL_FREE
))
1109 if (likely(!node
)) {
1110 hlist_add_head(&inode
->i_hash
, head
);
1111 spin_unlock(&inode_lock
);
1115 spin_unlock(&inode_lock
);
1117 if (unlikely(!hlist_unhashed(&old
->i_hash
))) {
1124 EXPORT_SYMBOL(insert_inode_locked
);
1126 int insert_inode_locked4(struct inode
*inode
, unsigned long hashval
,
1127 int (*test
)(struct inode
*, void *), void *data
)
1129 struct super_block
*sb
= inode
->i_sb
;
1130 struct hlist_head
*head
= inode_hashtable
+ hash(sb
, hashval
);
1132 inode
->i_state
|= I_NEW
;
1135 struct hlist_node
*node
;
1136 struct inode
*old
= NULL
;
1138 spin_lock(&inode_lock
);
1139 hlist_for_each_entry(old
, node
, head
, i_hash
) {
1140 if (old
->i_sb
!= sb
)
1142 if (!test(old
, data
))
1144 if (old
->i_state
& (I_FREEING
|I_WILL_FREE
))
1148 if (likely(!node
)) {
1149 hlist_add_head(&inode
->i_hash
, head
);
1150 spin_unlock(&inode_lock
);
1154 spin_unlock(&inode_lock
);
1156 if (unlikely(!hlist_unhashed(&old
->i_hash
))) {
1163 EXPORT_SYMBOL(insert_inode_locked4
);
1166 * __insert_inode_hash - hash an inode
1167 * @inode: unhashed inode
1168 * @hashval: unsigned long value used to locate this object in the
1171 * Add an inode to the inode hash for this superblock.
1173 void __insert_inode_hash(struct inode
*inode
, unsigned long hashval
)
1175 struct hlist_head
*head
= inode_hashtable
+ hash(inode
->i_sb
, hashval
);
1176 spin_lock(&inode_lock
);
1177 hlist_add_head(&inode
->i_hash
, head
);
1178 spin_unlock(&inode_lock
);
1180 EXPORT_SYMBOL(__insert_inode_hash
);
1183 * remove_inode_hash - remove an inode from the hash
1184 * @inode: inode to unhash
1186 * Remove an inode from the superblock.
1188 void remove_inode_hash(struct inode
*inode
)
1190 spin_lock(&inode_lock
);
1191 hlist_del_init(&inode
->i_hash
);
1192 spin_unlock(&inode_lock
);
1194 EXPORT_SYMBOL(remove_inode_hash
);
1197 * Tell the filesystem that this inode is no longer of any interest and should
1198 * be completely destroyed.
1200 * We leave the inode in the inode hash table until *after* the filesystem's
1201 * ->delete_inode completes. This ensures that an iget (such as nfsd might
1202 * instigate) will always find up-to-date information either in the hash or on
1205 * I_FREEING is set so that no-one will take a new reference to the inode while
1206 * it is being deleted.
1208 void generic_delete_inode(struct inode
*inode
)
1210 list_del_init(&inode
->i_list
);
1211 list_del_init(&inode
->i_sb_list
);
1212 WARN_ON(inode
->i_state
& I_NEW
);
1213 inode
->i_state
|= I_FREEING
;
1214 inodes_stat
.nr_inodes
--;
1215 spin_unlock(&inode_lock
);
1219 spin_lock(&inode_lock
);
1220 hlist_del_init(&inode
->i_hash
);
1221 spin_unlock(&inode_lock
);
1222 wake_up_inode(inode
);
1223 BUG_ON(inode
->i_state
!= (I_FREEING
| I_CLEAR
));
1224 destroy_inode(inode
);
1226 EXPORT_SYMBOL(generic_delete_inode
);
1229 * generic_detach_inode - remove inode from inode lists
1230 * @inode: inode to remove
1232 * Remove inode from inode lists, write it if it's dirty. This is just an
1233 * internal VFS helper exported for hugetlbfs. Do not use!
1235 * Returns 1 if inode should be completely destroyed.
1237 static int generic_detach_inode(struct inode
*inode
)
1239 struct super_block
*sb
= inode
->i_sb
;
1241 if (!hlist_unhashed(&inode
->i_hash
)) {
1242 if (!(inode
->i_state
& (I_DIRTY
|I_SYNC
)))
1243 list_move(&inode
->i_list
, &inode_unused
);
1244 inodes_stat
.nr_unused
++;
1245 if (sb
->s_flags
& MS_ACTIVE
) {
1246 spin_unlock(&inode_lock
);
1249 WARN_ON(inode
->i_state
& I_NEW
);
1250 inode
->i_state
|= I_WILL_FREE
;
1251 spin_unlock(&inode_lock
);
1252 write_inode_now(inode
, 1);
1253 spin_lock(&inode_lock
);
1254 WARN_ON(inode
->i_state
& I_NEW
);
1255 inode
->i_state
&= ~I_WILL_FREE
;
1256 inodes_stat
.nr_unused
--;
1257 hlist_del_init(&inode
->i_hash
);
1259 list_del_init(&inode
->i_list
);
1260 list_del_init(&inode
->i_sb_list
);
1261 WARN_ON(inode
->i_state
& I_NEW
);
1262 inode
->i_state
|= I_FREEING
;
1263 inodes_stat
.nr_inodes
--;
1264 spin_unlock(&inode_lock
);
1268 static void generic_forget_inode(struct inode
*inode
)
1270 if (!generic_detach_inode(inode
))
1273 wake_up_inode(inode
);
1274 destroy_inode(inode
);
1278 * Normal UNIX filesystem behaviour: delete the
1279 * inode when the usage count drops to zero, and
1282 void generic_drop_inode(struct inode
*inode
)
1284 if (!inode
->i_nlink
)
1285 generic_delete_inode(inode
);
1287 generic_forget_inode(inode
);
1289 EXPORT_SYMBOL_GPL(generic_drop_inode
);
1292 * Called when we're dropping the last reference
1295 * Call the FS "drop()" function, defaulting to
1296 * the legacy UNIX filesystem behaviour..
1298 * NOTE! NOTE! NOTE! We're called with the inode lock
1299 * held, and the drop function is supposed to release
1302 static inline void iput_final(struct inode
*inode
)
1304 const struct super_operations
*op
= inode
->i_sb
->s_op
;
1305 void (*drop
)(struct inode
*) = generic_drop_inode
;
1307 if (op
&& op
->drop_inode
)
1308 drop
= op
->drop_inode
;
1313 * iput - put an inode
1314 * @inode: inode to put
1316 * Puts an inode, dropping its usage count. If the inode use count hits
1317 * zero, the inode is then freed and may also be destroyed.
1319 * Consequently, iput() can sleep.
1321 void iput(struct inode
*inode
)
1324 BUG_ON(inode
->i_state
& I_CLEAR
);
1326 if (atomic_dec_and_lock(&inode
->i_count
, &inode_lock
))
1330 EXPORT_SYMBOL(iput
);
1333 * bmap - find a block number in a file
1334 * @inode: inode of file
1335 * @block: block to find
1337 * Returns the block number on the device holding the inode that
1338 * is the disk block number for the block of the file requested.
1339 * That is, asked for block 4 of inode 1 the function will return the
1340 * disk block relative to the disk start that holds that block of the
1343 sector_t
bmap(struct inode
*inode
, sector_t block
)
1346 if (inode
->i_mapping
->a_ops
->bmap
)
1347 res
= inode
->i_mapping
->a_ops
->bmap(inode
->i_mapping
, block
);
1350 EXPORT_SYMBOL(bmap
);
1353 * With relative atime, only update atime if the previous atime is
1354 * earlier than either the ctime or mtime or if at least a day has
1355 * passed since the last atime update.
1357 static int relatime_need_update(struct vfsmount
*mnt
, struct inode
*inode
,
1358 struct timespec now
)
1361 if (!(mnt
->mnt_flags
& MNT_RELATIME
))
1364 * Is mtime younger than atime? If yes, update atime:
1366 if (timespec_compare(&inode
->i_mtime
, &inode
->i_atime
) >= 0)
1369 * Is ctime younger than atime? If yes, update atime:
1371 if (timespec_compare(&inode
->i_ctime
, &inode
->i_atime
) >= 0)
1375 * Is the previous atime value older than a day? If yes,
1378 if ((long)(now
.tv_sec
- inode
->i_atime
.tv_sec
) >= 24*60*60)
1381 * Good, we can skip the atime update:
1387 * touch_atime - update the access time
1388 * @mnt: mount the inode is accessed on
1389 * @dentry: dentry accessed
1391 * Update the accessed time on an inode and mark it for writeback.
1392 * This function automatically handles read only file systems and media,
1393 * as well as the "noatime" flag and inode specific "noatime" markers.
1395 void touch_atime(struct vfsmount
*mnt
, struct dentry
*dentry
)
1397 struct inode
*inode
= dentry
->d_inode
;
1398 struct timespec now
;
1400 if (inode
->i_flags
& S_NOATIME
)
1402 if (IS_NOATIME(inode
))
1404 if ((inode
->i_sb
->s_flags
& MS_NODIRATIME
) && S_ISDIR(inode
->i_mode
))
1407 if (mnt
->mnt_flags
& MNT_NOATIME
)
1409 if ((mnt
->mnt_flags
& MNT_NODIRATIME
) && S_ISDIR(inode
->i_mode
))
1412 now
= current_fs_time(inode
->i_sb
);
1414 if (!relatime_need_update(mnt
, inode
, now
))
1417 if (timespec_equal(&inode
->i_atime
, &now
))
1420 if (mnt_want_write(mnt
))
1423 inode
->i_atime
= now
;
1424 mark_inode_dirty_sync(inode
);
1425 mnt_drop_write(mnt
);
1427 EXPORT_SYMBOL(touch_atime
);
1430 * file_update_time - update mtime and ctime time
1431 * @file: file accessed
1433 * Update the mtime and ctime members of an inode and mark the inode
1434 * for writeback. Note that this function is meant exclusively for
1435 * usage in the file write path of filesystems, and filesystems may
1436 * choose to explicitly ignore update via this function with the
1437 * S_NOCMTIME inode flag, e.g. for network filesystem where these
1438 * timestamps are handled by the server.
1441 void file_update_time(struct file
*file
)
1443 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1444 struct timespec now
;
1445 enum { S_MTIME
= 1, S_CTIME
= 2, S_VERSION
= 4 } sync_it
= 0;
1447 /* First try to exhaust all avenues to not sync */
1448 if (IS_NOCMTIME(inode
))
1451 now
= current_fs_time(inode
->i_sb
);
1452 if (!timespec_equal(&inode
->i_mtime
, &now
))
1455 if (!timespec_equal(&inode
->i_ctime
, &now
))
1458 if (IS_I_VERSION(inode
))
1459 sync_it
|= S_VERSION
;
1464 /* Finally allowed to write? Takes lock. */
1465 if (mnt_want_write_file(file
))
1468 /* Only change inode inside the lock region */
1469 if (sync_it
& S_VERSION
)
1470 inode_inc_iversion(inode
);
1471 if (sync_it
& S_CTIME
)
1472 inode
->i_ctime
= now
;
1473 if (sync_it
& S_MTIME
)
1474 inode
->i_mtime
= now
;
1475 mark_inode_dirty_sync(inode
);
1476 mnt_drop_write(file
->f_path
.mnt
);
1478 EXPORT_SYMBOL(file_update_time
);
1480 int inode_needs_sync(struct inode
*inode
)
1484 if (S_ISDIR(inode
->i_mode
) && IS_DIRSYNC(inode
))
1488 EXPORT_SYMBOL(inode_needs_sync
);
1490 int inode_wait(void *word
)
1495 EXPORT_SYMBOL(inode_wait
);
1498 * If we try to find an inode in the inode hash while it is being
1499 * deleted, we have to wait until the filesystem completes its
1500 * deletion before reporting that it isn't found. This function waits
1501 * until the deletion _might_ have completed. Callers are responsible
1502 * to recheck inode state.
1504 * It doesn't matter if I_NEW is not set initially, a call to
1505 * wake_up_inode() after removing from the hash list will DTRT.
1507 * This is called with inode_lock held.
1509 static void __wait_on_freeing_inode(struct inode
*inode
)
1511 wait_queue_head_t
*wq
;
1512 DEFINE_WAIT_BIT(wait
, &inode
->i_state
, __I_NEW
);
1513 wq
= bit_waitqueue(&inode
->i_state
, __I_NEW
);
1514 prepare_to_wait(wq
, &wait
.wait
, TASK_UNINTERRUPTIBLE
);
1515 spin_unlock(&inode_lock
);
1517 finish_wait(wq
, &wait
.wait
);
1518 spin_lock(&inode_lock
);
1521 static __initdata
unsigned long ihash_entries
;
1522 static int __init
set_ihash_entries(char *str
)
1526 ihash_entries
= simple_strtoul(str
, &str
, 0);
1529 __setup("ihash_entries=", set_ihash_entries
);
1532 * Initialize the waitqueues and inode hash table.
1534 void __init
inode_init_early(void)
1538 /* If hashes are distributed across NUMA nodes, defer
1539 * hash allocation until vmalloc space is available.
1545 alloc_large_system_hash("Inode-cache",
1546 sizeof(struct hlist_head
),
1554 for (loop
= 0; loop
< (1 << i_hash_shift
); loop
++)
1555 INIT_HLIST_HEAD(&inode_hashtable
[loop
]);
1558 void __init
inode_init(void)
1562 /* inode slab cache */
1563 inode_cachep
= kmem_cache_create("inode_cache",
1564 sizeof(struct inode
),
1566 (SLAB_RECLAIM_ACCOUNT
|SLAB_PANIC
|
1569 register_shrinker(&icache_shrinker
);
1571 /* Hash may have been set up in inode_init_early */
1576 alloc_large_system_hash("Inode-cache",
1577 sizeof(struct hlist_head
),
1585 for (loop
= 0; loop
< (1 << i_hash_shift
); loop
++)
1586 INIT_HLIST_HEAD(&inode_hashtable
[loop
]);
1589 void init_special_inode(struct inode
*inode
, umode_t mode
, dev_t rdev
)
1591 inode
->i_mode
= mode
;
1592 if (S_ISCHR(mode
)) {
1593 inode
->i_fop
= &def_chr_fops
;
1594 inode
->i_rdev
= rdev
;
1595 } else if (S_ISBLK(mode
)) {
1596 inode
->i_fop
= &def_blk_fops
;
1597 inode
->i_rdev
= rdev
;
1598 } else if (S_ISFIFO(mode
))
1599 inode
->i_fop
= &def_fifo_fops
;
1600 else if (S_ISSOCK(mode
))
1601 inode
->i_fop
= &bad_sock_fops
;
1603 printk(KERN_DEBUG
"init_special_inode: bogus i_mode (%o) for"
1604 " inode %s:%lu\n", mode
, inode
->i_sb
->s_id
,
1607 EXPORT_SYMBOL(init_special_inode
);
1610 * Init uid,gid,mode for new inode according to posix standards
1612 * @dir: Directory inode
1613 * @mode: mode of the new inode
1615 void inode_init_owner(struct inode
*inode
, const struct inode
*dir
,
1618 inode
->i_uid
= current_fsuid();
1619 if (dir
&& dir
->i_mode
& S_ISGID
) {
1620 inode
->i_gid
= dir
->i_gid
;
1624 inode
->i_gid
= current_fsgid();
1625 inode
->i_mode
= mode
;
1627 EXPORT_SYMBOL(inode_init_owner
);