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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/inode.c | |
3 | * | |
4 | * (C) 1997 Linus Torvalds | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/fs.h> |
8 | #include <linux/mm.h> | |
9 | #include <linux/dcache.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/quotaops.h> | |
12 | #include <linux/slab.h> | |
13 | #include <linux/writeback.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/backing-dev.h> | |
16 | #include <linux/wait.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> | |
0eeca283 | 23 | #include <linux/inotify.h> |
fc33a7bb | 24 | #include <linux/mount.h> |
1da177e4 LT |
25 | |
26 | /* | |
27 | * This is needed for the following functions: | |
28 | * - inode_has_buffers | |
29 | * - invalidate_inode_buffers | |
1da177e4 LT |
30 | * - invalidate_bdev |
31 | * | |
32 | * FIXME: remove all knowledge of the buffer layer from this file | |
33 | */ | |
34 | #include <linux/buffer_head.h> | |
35 | ||
36 | /* | |
37 | * New inode.c implementation. | |
38 | * | |
39 | * This implementation has the basic premise of trying | |
40 | * to be extremely low-overhead and SMP-safe, yet be | |
41 | * simple enough to be "obviously correct". | |
42 | * | |
43 | * Famous last words. | |
44 | */ | |
45 | ||
46 | /* inode dynamic allocation 1999, Andrea Arcangeli <[email protected]> */ | |
47 | ||
48 | /* #define INODE_PARANOIA 1 */ | |
49 | /* #define INODE_DEBUG 1 */ | |
50 | ||
51 | /* | |
52 | * Inode lookup is no longer as critical as it used to be: | |
53 | * most of the lookups are going to be through the dcache. | |
54 | */ | |
55 | #define I_HASHBITS i_hash_shift | |
56 | #define I_HASHMASK i_hash_mask | |
57 | ||
fa3536cc ED |
58 | static unsigned int i_hash_mask __read_mostly; |
59 | static unsigned int i_hash_shift __read_mostly; | |
1da177e4 LT |
60 | |
61 | /* | |
62 | * Each inode can be on two separate lists. One is | |
63 | * the hash list of the inode, used for lookups. The | |
64 | * other linked list is the "type" list: | |
65 | * "in_use" - valid inode, i_count > 0, i_nlink > 0 | |
66 | * "dirty" - as "in_use" but also dirty | |
67 | * "unused" - valid inode, i_count = 0 | |
68 | * | |
69 | * A "dirty" list is maintained for each super block, | |
70 | * allowing for low-overhead inode sync() operations. | |
71 | */ | |
72 | ||
73 | LIST_HEAD(inode_in_use); | |
74 | LIST_HEAD(inode_unused); | |
fa3536cc | 75 | static struct hlist_head *inode_hashtable __read_mostly; |
1da177e4 LT |
76 | |
77 | /* | |
78 | * A simple spinlock to protect the list manipulations. | |
79 | * | |
80 | * NOTE! You also have to own the lock if you change | |
81 | * the i_state of an inode while it is in use.. | |
82 | */ | |
83 | DEFINE_SPINLOCK(inode_lock); | |
84 | ||
85 | /* | |
f24075bd | 86 | * iprune_mutex provides exclusion between the kswapd or try_to_free_pages |
1da177e4 LT |
87 | * icache shrinking path, and the umount path. Without this exclusion, |
88 | * by the time prune_icache calls iput for the inode whose pages it has | |
89 | * been invalidating, or by the time it calls clear_inode & destroy_inode | |
90 | * from its final dispose_list, the struct super_block they refer to | |
91 | * (for inode->i_sb->s_op) may already have been freed and reused. | |
92 | */ | |
bdfc3266 | 93 | static DEFINE_MUTEX(iprune_mutex); |
1da177e4 LT |
94 | |
95 | /* | |
96 | * Statistics gathering.. | |
97 | */ | |
98 | struct inodes_stat_t inodes_stat; | |
99 | ||
e18b890b | 100 | static struct kmem_cache * inode_cachep __read_mostly; |
1da177e4 | 101 | |
1c0eeaf5 JE |
102 | static void wake_up_inode(struct inode *inode) |
103 | { | |
104 | /* | |
105 | * Prevent speculative execution through spin_unlock(&inode_lock); | |
106 | */ | |
107 | smp_mb(); | |
108 | wake_up_bit(&inode->i_state, __I_LOCK); | |
109 | } | |
110 | ||
1da177e4 LT |
111 | static struct inode *alloc_inode(struct super_block *sb) |
112 | { | |
f5e54d6e | 113 | static const struct address_space_operations empty_aops; |
1da177e4 | 114 | static struct inode_operations empty_iops; |
99ac48f5 | 115 | static const struct file_operations empty_fops; |
1da177e4 LT |
116 | struct inode *inode; |
117 | ||
118 | if (sb->s_op->alloc_inode) | |
119 | inode = sb->s_op->alloc_inode(sb); | |
120 | else | |
e94b1766 | 121 | inode = (struct inode *) kmem_cache_alloc(inode_cachep, GFP_KERNEL); |
1da177e4 LT |
122 | |
123 | if (inode) { | |
124 | struct address_space * const mapping = &inode->i_data; | |
125 | ||
126 | inode->i_sb = sb; | |
127 | inode->i_blkbits = sb->s_blocksize_bits; | |
128 | inode->i_flags = 0; | |
129 | atomic_set(&inode->i_count, 1); | |
130 | inode->i_op = &empty_iops; | |
131 | inode->i_fop = &empty_fops; | |
132 | inode->i_nlink = 1; | |
133 | atomic_set(&inode->i_writecount, 0); | |
134 | inode->i_size = 0; | |
135 | inode->i_blocks = 0; | |
136 | inode->i_bytes = 0; | |
137 | inode->i_generation = 0; | |
138 | #ifdef CONFIG_QUOTA | |
139 | memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); | |
140 | #endif | |
141 | inode->i_pipe = NULL; | |
142 | inode->i_bdev = NULL; | |
143 | inode->i_cdev = NULL; | |
144 | inode->i_rdev = 0; | |
1da177e4 LT |
145 | inode->dirtied_when = 0; |
146 | if (security_inode_alloc(inode)) { | |
147 | if (inode->i_sb->s_op->destroy_inode) | |
148 | inode->i_sb->s_op->destroy_inode(inode); | |
149 | else | |
150 | kmem_cache_free(inode_cachep, (inode)); | |
151 | return NULL; | |
152 | } | |
153 | ||
d475fd42 PZ |
154 | spin_lock_init(&inode->i_lock); |
155 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); | |
156 | ||
157 | mutex_init(&inode->i_mutex); | |
158 | lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); | |
159 | ||
160 | init_rwsem(&inode->i_alloc_sem); | |
161 | lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key); | |
162 | ||
1da177e4 LT |
163 | mapping->a_ops = &empty_aops; |
164 | mapping->host = inode; | |
165 | mapping->flags = 0; | |
769848c0 | 166 | mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE); |
1da177e4 LT |
167 | mapping->assoc_mapping = NULL; |
168 | mapping->backing_dev_info = &default_backing_dev_info; | |
169 | ||
170 | /* | |
171 | * If the block_device provides a backing_dev_info for client | |
172 | * inodes then use that. Otherwise the inode share the bdev's | |
173 | * backing_dev_info. | |
174 | */ | |
175 | if (sb->s_bdev) { | |
176 | struct backing_dev_info *bdi; | |
177 | ||
178 | bdi = sb->s_bdev->bd_inode_backing_dev_info; | |
179 | if (!bdi) | |
180 | bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info; | |
181 | mapping->backing_dev_info = bdi; | |
182 | } | |
e6c6e640 | 183 | inode->i_private = NULL; |
1da177e4 LT |
184 | inode->i_mapping = mapping; |
185 | } | |
186 | return inode; | |
187 | } | |
188 | ||
189 | void destroy_inode(struct inode *inode) | |
190 | { | |
b7542f8c | 191 | BUG_ON(inode_has_buffers(inode)); |
1da177e4 LT |
192 | security_inode_free(inode); |
193 | if (inode->i_sb->s_op->destroy_inode) | |
194 | inode->i_sb->s_op->destroy_inode(inode); | |
195 | else | |
196 | kmem_cache_free(inode_cachep, (inode)); | |
197 | } | |
198 | ||
199 | ||
200 | /* | |
201 | * These are initializations that only need to be done | |
202 | * once, because the fields are idempotent across use | |
203 | * of the inode, so let the slab aware of that. | |
204 | */ | |
205 | void inode_init_once(struct inode *inode) | |
206 | { | |
207 | memset(inode, 0, sizeof(*inode)); | |
208 | INIT_HLIST_NODE(&inode->i_hash); | |
209 | INIT_LIST_HEAD(&inode->i_dentry); | |
210 | INIT_LIST_HEAD(&inode->i_devices); | |
1da177e4 LT |
211 | INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC); |
212 | rwlock_init(&inode->i_data.tree_lock); | |
213 | spin_lock_init(&inode->i_data.i_mmap_lock); | |
214 | INIT_LIST_HEAD(&inode->i_data.private_list); | |
215 | spin_lock_init(&inode->i_data.private_lock); | |
216 | INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap); | |
217 | INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear); | |
1da177e4 | 218 | i_size_ordered_init(inode); |
0eeca283 RL |
219 | #ifdef CONFIG_INOTIFY |
220 | INIT_LIST_HEAD(&inode->inotify_watches); | |
d4f9af9d | 221 | mutex_init(&inode->inotify_mutex); |
0eeca283 | 222 | #endif |
1da177e4 LT |
223 | } |
224 | ||
225 | EXPORT_SYMBOL(inode_init_once); | |
226 | ||
4ba9b9d0 | 227 | static void init_once(struct kmem_cache * cachep, void *foo) |
1da177e4 LT |
228 | { |
229 | struct inode * inode = (struct inode *) foo; | |
230 | ||
a35afb83 | 231 | inode_init_once(inode); |
1da177e4 LT |
232 | } |
233 | ||
234 | /* | |
235 | * inode_lock must be held | |
236 | */ | |
237 | void __iget(struct inode * inode) | |
238 | { | |
239 | if (atomic_read(&inode->i_count)) { | |
240 | atomic_inc(&inode->i_count); | |
241 | return; | |
242 | } | |
243 | atomic_inc(&inode->i_count); | |
1c0eeaf5 | 244 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1da177e4 LT |
245 | list_move(&inode->i_list, &inode_in_use); |
246 | inodes_stat.nr_unused--; | |
247 | } | |
248 | ||
249 | /** | |
250 | * clear_inode - clear an inode | |
251 | * @inode: inode to clear | |
252 | * | |
253 | * This is called by the filesystem to tell us | |
254 | * that the inode is no longer useful. We just | |
255 | * terminate it with extreme prejudice. | |
256 | */ | |
257 | void clear_inode(struct inode *inode) | |
258 | { | |
259 | might_sleep(); | |
260 | invalidate_inode_buffers(inode); | |
261 | ||
b7542f8c ES |
262 | BUG_ON(inode->i_data.nrpages); |
263 | BUG_ON(!(inode->i_state & I_FREEING)); | |
264 | BUG_ON(inode->i_state & I_CLEAR); | |
1c0eeaf5 | 265 | inode_sync_wait(inode); |
1da177e4 | 266 | DQUOT_DROP(inode); |
acb0c854 | 267 | if (inode->i_sb->s_op->clear_inode) |
1da177e4 | 268 | inode->i_sb->s_op->clear_inode(inode); |
eaf796e7 | 269 | if (S_ISBLK(inode->i_mode) && inode->i_bdev) |
1da177e4 | 270 | bd_forget(inode); |
577c4eb0 | 271 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
1da177e4 LT |
272 | cd_forget(inode); |
273 | inode->i_state = I_CLEAR; | |
274 | } | |
275 | ||
276 | EXPORT_SYMBOL(clear_inode); | |
277 | ||
278 | /* | |
279 | * dispose_list - dispose of the contents of a local list | |
280 | * @head: the head of the list to free | |
281 | * | |
282 | * Dispose-list gets a local list with local inodes in it, so it doesn't | |
283 | * need to worry about list corruption and SMP locks. | |
284 | */ | |
285 | static void dispose_list(struct list_head *head) | |
286 | { | |
287 | int nr_disposed = 0; | |
288 | ||
289 | while (!list_empty(head)) { | |
290 | struct inode *inode; | |
291 | ||
b5e61818 | 292 | inode = list_first_entry(head, struct inode, i_list); |
1da177e4 LT |
293 | list_del(&inode->i_list); |
294 | ||
295 | if (inode->i_data.nrpages) | |
296 | truncate_inode_pages(&inode->i_data, 0); | |
297 | clear_inode(inode); | |
4120db47 AB |
298 | |
299 | spin_lock(&inode_lock); | |
300 | hlist_del_init(&inode->i_hash); | |
301 | list_del_init(&inode->i_sb_list); | |
302 | spin_unlock(&inode_lock); | |
303 | ||
304 | wake_up_inode(inode); | |
1da177e4 LT |
305 | destroy_inode(inode); |
306 | nr_disposed++; | |
307 | } | |
308 | spin_lock(&inode_lock); | |
309 | inodes_stat.nr_inodes -= nr_disposed; | |
310 | spin_unlock(&inode_lock); | |
311 | } | |
312 | ||
313 | /* | |
314 | * Invalidate all inodes for a device. | |
315 | */ | |
316 | static int invalidate_list(struct list_head *head, struct list_head *dispose) | |
317 | { | |
318 | struct list_head *next; | |
319 | int busy = 0, count = 0; | |
320 | ||
321 | next = head->next; | |
322 | for (;;) { | |
323 | struct list_head * tmp = next; | |
324 | struct inode * inode; | |
325 | ||
326 | /* | |
327 | * We can reschedule here without worrying about the list's | |
328 | * consistency because the per-sb list of inodes must not | |
f24075bd | 329 | * change during umount anymore, and because iprune_mutex keeps |
1da177e4 LT |
330 | * shrink_icache_memory() away. |
331 | */ | |
332 | cond_resched_lock(&inode_lock); | |
333 | ||
334 | next = next->next; | |
335 | if (tmp == head) | |
336 | break; | |
337 | inode = list_entry(tmp, struct inode, i_sb_list); | |
338 | invalidate_inode_buffers(inode); | |
339 | if (!atomic_read(&inode->i_count)) { | |
1da177e4 LT |
340 | list_move(&inode->i_list, dispose); |
341 | inode->i_state |= I_FREEING; | |
342 | count++; | |
343 | continue; | |
344 | } | |
345 | busy = 1; | |
346 | } | |
347 | /* only unused inodes may be cached with i_count zero */ | |
348 | inodes_stat.nr_unused -= count; | |
349 | return busy; | |
350 | } | |
351 | ||
1da177e4 LT |
352 | /** |
353 | * invalidate_inodes - discard the inodes on a device | |
354 | * @sb: superblock | |
355 | * | |
356 | * Discard all of the inodes for a given superblock. If the discard | |
357 | * fails because there are busy inodes then a non zero value is returned. | |
358 | * If the discard is successful all the inodes have been discarded. | |
359 | */ | |
360 | int invalidate_inodes(struct super_block * sb) | |
361 | { | |
362 | int busy; | |
363 | LIST_HEAD(throw_away); | |
364 | ||
f24075bd | 365 | mutex_lock(&iprune_mutex); |
1da177e4 | 366 | spin_lock(&inode_lock); |
0eeca283 | 367 | inotify_unmount_inodes(&sb->s_inodes); |
1da177e4 LT |
368 | busy = invalidate_list(&sb->s_inodes, &throw_away); |
369 | spin_unlock(&inode_lock); | |
370 | ||
371 | dispose_list(&throw_away); | |
f24075bd | 372 | mutex_unlock(&iprune_mutex); |
1da177e4 LT |
373 | |
374 | return busy; | |
375 | } | |
376 | ||
377 | EXPORT_SYMBOL(invalidate_inodes); | |
1da177e4 LT |
378 | |
379 | static int can_unuse(struct inode *inode) | |
380 | { | |
381 | if (inode->i_state) | |
382 | return 0; | |
383 | if (inode_has_buffers(inode)) | |
384 | return 0; | |
385 | if (atomic_read(&inode->i_count)) | |
386 | return 0; | |
387 | if (inode->i_data.nrpages) | |
388 | return 0; | |
389 | return 1; | |
390 | } | |
391 | ||
392 | /* | |
393 | * Scan `goal' inodes on the unused list for freeable ones. They are moved to | |
394 | * a temporary list and then are freed outside inode_lock by dispose_list(). | |
395 | * | |
396 | * Any inodes which are pinned purely because of attached pagecache have their | |
397 | * pagecache removed. We expect the final iput() on that inode to add it to | |
398 | * the front of the inode_unused list. So look for it there and if the | |
399 | * inode is still freeable, proceed. The right inode is found 99.9% of the | |
400 | * time in testing on a 4-way. | |
401 | * | |
402 | * If the inode has metadata buffers attached to mapping->private_list then | |
403 | * try to remove them. | |
404 | */ | |
405 | static void prune_icache(int nr_to_scan) | |
406 | { | |
407 | LIST_HEAD(freeable); | |
408 | int nr_pruned = 0; | |
409 | int nr_scanned; | |
410 | unsigned long reap = 0; | |
411 | ||
f24075bd | 412 | mutex_lock(&iprune_mutex); |
1da177e4 LT |
413 | spin_lock(&inode_lock); |
414 | for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) { | |
415 | struct inode *inode; | |
416 | ||
417 | if (list_empty(&inode_unused)) | |
418 | break; | |
419 | ||
420 | inode = list_entry(inode_unused.prev, struct inode, i_list); | |
421 | ||
422 | if (inode->i_state || atomic_read(&inode->i_count)) { | |
423 | list_move(&inode->i_list, &inode_unused); | |
424 | continue; | |
425 | } | |
426 | if (inode_has_buffers(inode) || inode->i_data.nrpages) { | |
427 | __iget(inode); | |
428 | spin_unlock(&inode_lock); | |
429 | if (remove_inode_buffers(inode)) | |
fc0ecff6 AM |
430 | reap += invalidate_mapping_pages(&inode->i_data, |
431 | 0, -1); | |
1da177e4 LT |
432 | iput(inode); |
433 | spin_lock(&inode_lock); | |
434 | ||
435 | if (inode != list_entry(inode_unused.next, | |
436 | struct inode, i_list)) | |
437 | continue; /* wrong inode or list_empty */ | |
438 | if (!can_unuse(inode)) | |
439 | continue; | |
440 | } | |
1da177e4 LT |
441 | list_move(&inode->i_list, &freeable); |
442 | inode->i_state |= I_FREEING; | |
443 | nr_pruned++; | |
444 | } | |
445 | inodes_stat.nr_unused -= nr_pruned; | |
f8891e5e CL |
446 | if (current_is_kswapd()) |
447 | __count_vm_events(KSWAPD_INODESTEAL, reap); | |
448 | else | |
449 | __count_vm_events(PGINODESTEAL, reap); | |
1da177e4 LT |
450 | spin_unlock(&inode_lock); |
451 | ||
452 | dispose_list(&freeable); | |
f24075bd | 453 | mutex_unlock(&iprune_mutex); |
1da177e4 LT |
454 | } |
455 | ||
456 | /* | |
457 | * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, | |
458 | * "unused" means that no dentries are referring to the inodes: the files are | |
459 | * not open and the dcache references to those inodes have already been | |
460 | * reclaimed. | |
461 | * | |
462 | * This function is passed the number of inodes to scan, and it returns the | |
463 | * total number of remaining possibly-reclaimable inodes. | |
464 | */ | |
27496a8c | 465 | static int shrink_icache_memory(int nr, gfp_t gfp_mask) |
1da177e4 LT |
466 | { |
467 | if (nr) { | |
468 | /* | |
469 | * Nasty deadlock avoidance. We may hold various FS locks, | |
470 | * and we don't want to recurse into the FS that called us | |
471 | * in clear_inode() and friends.. | |
472 | */ | |
473 | if (!(gfp_mask & __GFP_FS)) | |
474 | return -1; | |
475 | prune_icache(nr); | |
476 | } | |
477 | return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure; | |
478 | } | |
479 | ||
8e1f936b RR |
480 | static struct shrinker icache_shrinker = { |
481 | .shrink = shrink_icache_memory, | |
482 | .seeks = DEFAULT_SEEKS, | |
483 | }; | |
484 | ||
1da177e4 LT |
485 | static void __wait_on_freeing_inode(struct inode *inode); |
486 | /* | |
487 | * Called with the inode lock held. | |
488 | * NOTE: we are not increasing the inode-refcount, you must call __iget() | |
489 | * by hand after calling find_inode now! This simplifies iunique and won't | |
490 | * add any additional branch in the common code. | |
491 | */ | |
492 | static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data) | |
493 | { | |
494 | struct hlist_node *node; | |
495 | struct inode * inode = NULL; | |
496 | ||
497 | repeat: | |
498 | hlist_for_each (node, head) { | |
499 | inode = hlist_entry(node, struct inode, i_hash); | |
500 | if (inode->i_sb != sb) | |
501 | continue; | |
502 | if (!test(inode, data)) | |
503 | continue; | |
991114c6 | 504 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
1da177e4 LT |
505 | __wait_on_freeing_inode(inode); |
506 | goto repeat; | |
507 | } | |
508 | break; | |
509 | } | |
510 | return node ? inode : NULL; | |
511 | } | |
512 | ||
513 | /* | |
514 | * find_inode_fast is the fast path version of find_inode, see the comment at | |
515 | * iget_locked for details. | |
516 | */ | |
517 | static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino) | |
518 | { | |
519 | struct hlist_node *node; | |
520 | struct inode * inode = NULL; | |
521 | ||
522 | repeat: | |
523 | hlist_for_each (node, head) { | |
524 | inode = hlist_entry(node, struct inode, i_hash); | |
525 | if (inode->i_ino != ino) | |
526 | continue; | |
527 | if (inode->i_sb != sb) | |
528 | continue; | |
991114c6 | 529 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) { |
1da177e4 LT |
530 | __wait_on_freeing_inode(inode); |
531 | goto repeat; | |
532 | } | |
533 | break; | |
534 | } | |
535 | return node ? inode : NULL; | |
536 | } | |
537 | ||
538 | /** | |
539 | * new_inode - obtain an inode | |
540 | * @sb: superblock | |
541 | * | |
769848c0 MG |
542 | * Allocates a new inode for given superblock. The default gfp_mask |
543 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_PAGECACHE. | |
544 | * If HIGHMEM pages are unsuitable or it is known that pages allocated | |
545 | * for the page cache are not reclaimable or migratable, | |
546 | * mapping_set_gfp_mask() must be called with suitable flags on the | |
547 | * newly created inode's mapping | |
548 | * | |
1da177e4 LT |
549 | */ |
550 | struct inode *new_inode(struct super_block *sb) | |
551 | { | |
866b04fc JL |
552 | /* |
553 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW | |
554 | * error if st_ino won't fit in target struct field. Use 32bit counter | |
555 | * here to attempt to avoid that. | |
556 | */ | |
557 | static unsigned int last_ino; | |
1da177e4 LT |
558 | struct inode * inode; |
559 | ||
560 | spin_lock_prefetch(&inode_lock); | |
561 | ||
562 | inode = alloc_inode(sb); | |
563 | if (inode) { | |
564 | spin_lock(&inode_lock); | |
565 | inodes_stat.nr_inodes++; | |
566 | list_add(&inode->i_list, &inode_in_use); | |
567 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
568 | inode->i_ino = ++last_ino; | |
569 | inode->i_state = 0; | |
570 | spin_unlock(&inode_lock); | |
571 | } | |
572 | return inode; | |
573 | } | |
574 | ||
575 | EXPORT_SYMBOL(new_inode); | |
576 | ||
577 | void unlock_new_inode(struct inode *inode) | |
578 | { | |
14358e6d | 579 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
1e89a5e1 PZ |
580 | if (inode->i_mode & S_IFDIR) { |
581 | struct file_system_type *type = inode->i_sb->s_type; | |
582 | ||
583 | /* | |
584 | * ensure nobody is actually holding i_mutex | |
585 | */ | |
586 | mutex_destroy(&inode->i_mutex); | |
587 | mutex_init(&inode->i_mutex); | |
14358e6d | 588 | lockdep_set_class(&inode->i_mutex, &type->i_mutex_dir_key); |
1e89a5e1 | 589 | } |
14358e6d | 590 | #endif |
1da177e4 LT |
591 | /* |
592 | * This is special! We do not need the spinlock | |
593 | * when clearing I_LOCK, because we're guaranteed | |
594 | * that nobody else tries to do anything about the | |
595 | * state of the inode when it is locked, as we | |
596 | * just created it (so there can be no old holders | |
597 | * that haven't tested I_LOCK). | |
598 | */ | |
599 | inode->i_state &= ~(I_LOCK|I_NEW); | |
600 | wake_up_inode(inode); | |
601 | } | |
602 | ||
603 | EXPORT_SYMBOL(unlock_new_inode); | |
604 | ||
605 | /* | |
606 | * This is called without the inode lock held.. Be careful. | |
607 | * | |
608 | * We no longer cache the sb_flags in i_flags - see fs.h | |
609 | * -- [email protected] | |
610 | */ | |
611 | static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data) | |
612 | { | |
613 | struct inode * inode; | |
614 | ||
615 | inode = alloc_inode(sb); | |
616 | if (inode) { | |
617 | struct inode * old; | |
618 | ||
619 | spin_lock(&inode_lock); | |
620 | /* We released the lock, so.. */ | |
621 | old = find_inode(sb, head, test, data); | |
622 | if (!old) { | |
623 | if (set(inode, data)) | |
624 | goto set_failed; | |
625 | ||
626 | inodes_stat.nr_inodes++; | |
627 | list_add(&inode->i_list, &inode_in_use); | |
628 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
629 | hlist_add_head(&inode->i_hash, head); | |
630 | inode->i_state = I_LOCK|I_NEW; | |
631 | spin_unlock(&inode_lock); | |
632 | ||
633 | /* Return the locked inode with I_NEW set, the | |
634 | * caller is responsible for filling in the contents | |
635 | */ | |
636 | return inode; | |
637 | } | |
638 | ||
639 | /* | |
640 | * Uhhuh, somebody else created the same inode under | |
641 | * us. Use the old inode instead of the one we just | |
642 | * allocated. | |
643 | */ | |
644 | __iget(old); | |
645 | spin_unlock(&inode_lock); | |
646 | destroy_inode(inode); | |
647 | inode = old; | |
648 | wait_on_inode(inode); | |
649 | } | |
650 | return inode; | |
651 | ||
652 | set_failed: | |
653 | spin_unlock(&inode_lock); | |
654 | destroy_inode(inode); | |
655 | return NULL; | |
656 | } | |
657 | ||
658 | /* | |
659 | * get_new_inode_fast is the fast path version of get_new_inode, see the | |
660 | * comment at iget_locked for details. | |
661 | */ | |
662 | static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino) | |
663 | { | |
664 | struct inode * inode; | |
665 | ||
666 | inode = alloc_inode(sb); | |
667 | if (inode) { | |
668 | struct inode * old; | |
669 | ||
670 | spin_lock(&inode_lock); | |
671 | /* We released the lock, so.. */ | |
672 | old = find_inode_fast(sb, head, ino); | |
673 | if (!old) { | |
674 | inode->i_ino = ino; | |
675 | inodes_stat.nr_inodes++; | |
676 | list_add(&inode->i_list, &inode_in_use); | |
677 | list_add(&inode->i_sb_list, &sb->s_inodes); | |
678 | hlist_add_head(&inode->i_hash, head); | |
679 | inode->i_state = I_LOCK|I_NEW; | |
680 | spin_unlock(&inode_lock); | |
681 | ||
682 | /* Return the locked inode with I_NEW set, the | |
683 | * caller is responsible for filling in the contents | |
684 | */ | |
685 | return inode; | |
686 | } | |
687 | ||
688 | /* | |
689 | * Uhhuh, somebody else created the same inode under | |
690 | * us. Use the old inode instead of the one we just | |
691 | * allocated. | |
692 | */ | |
693 | __iget(old); | |
694 | spin_unlock(&inode_lock); | |
695 | destroy_inode(inode); | |
696 | inode = old; | |
697 | wait_on_inode(inode); | |
698 | } | |
699 | return inode; | |
700 | } | |
701 | ||
ed97bd37 | 702 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
1da177e4 LT |
703 | { |
704 | unsigned long tmp; | |
705 | ||
706 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / | |
707 | L1_CACHE_BYTES; | |
708 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); | |
709 | return tmp & I_HASHMASK; | |
710 | } | |
711 | ||
712 | /** | |
713 | * iunique - get a unique inode number | |
714 | * @sb: superblock | |
715 | * @max_reserved: highest reserved inode number | |
716 | * | |
717 | * Obtain an inode number that is unique on the system for a given | |
718 | * superblock. This is used by file systems that have no natural | |
719 | * permanent inode numbering system. An inode number is returned that | |
720 | * is higher than the reserved limit but unique. | |
721 | * | |
722 | * BUGS: | |
723 | * With a large number of inodes live on the file system this function | |
724 | * currently becomes quite slow. | |
725 | */ | |
726 | ino_t iunique(struct super_block *sb, ino_t max_reserved) | |
727 | { | |
866b04fc JL |
728 | /* |
729 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW | |
730 | * error if st_ino won't fit in target struct field. Use 32bit counter | |
731 | * here to attempt to avoid that. | |
732 | */ | |
733 | static unsigned int counter; | |
1da177e4 | 734 | struct inode *inode; |
3361c7be | 735 | struct hlist_head *head; |
1da177e4 | 736 | ino_t res; |
3361c7be | 737 | |
1da177e4 | 738 | spin_lock(&inode_lock); |
3361c7be JL |
739 | do { |
740 | if (counter <= max_reserved) | |
741 | counter = max_reserved + 1; | |
1da177e4 | 742 | res = counter++; |
3361c7be | 743 | head = inode_hashtable + hash(sb, res); |
1da177e4 | 744 | inode = find_inode_fast(sb, head, res); |
3361c7be JL |
745 | } while (inode != NULL); |
746 | spin_unlock(&inode_lock); | |
1da177e4 | 747 | |
3361c7be JL |
748 | return res; |
749 | } | |
1da177e4 LT |
750 | EXPORT_SYMBOL(iunique); |
751 | ||
752 | struct inode *igrab(struct inode *inode) | |
753 | { | |
754 | spin_lock(&inode_lock); | |
4a3b0a49 | 755 | if (!(inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE))) |
1da177e4 LT |
756 | __iget(inode); |
757 | else | |
758 | /* | |
759 | * Handle the case where s_op->clear_inode is not been | |
760 | * called yet, and somebody is calling igrab | |
761 | * while the inode is getting freed. | |
762 | */ | |
763 | inode = NULL; | |
764 | spin_unlock(&inode_lock); | |
765 | return inode; | |
766 | } | |
767 | ||
768 | EXPORT_SYMBOL(igrab); | |
769 | ||
770 | /** | |
771 | * ifind - internal function, you want ilookup5() or iget5(). | |
772 | * @sb: super block of file system to search | |
773 | * @head: the head of the list to search | |
774 | * @test: callback used for comparisons between inodes | |
775 | * @data: opaque data pointer to pass to @test | |
88bd5121 | 776 | * @wait: if true wait for the inode to be unlocked, if false do not |
1da177e4 LT |
777 | * |
778 | * ifind() searches for the inode specified by @data in the inode | |
779 | * cache. This is a generalized version of ifind_fast() for file systems where | |
780 | * the inode number is not sufficient for unique identification of an inode. | |
781 | * | |
782 | * If the inode is in the cache, the inode is returned with an incremented | |
783 | * reference count. | |
784 | * | |
785 | * Otherwise NULL is returned. | |
786 | * | |
787 | * Note, @test is called with the inode_lock held, so can't sleep. | |
788 | */ | |
5d2bea45 | 789 | static struct inode *ifind(struct super_block *sb, |
1da177e4 | 790 | struct hlist_head *head, int (*test)(struct inode *, void *), |
88bd5121 | 791 | void *data, const int wait) |
1da177e4 LT |
792 | { |
793 | struct inode *inode; | |
794 | ||
795 | spin_lock(&inode_lock); | |
796 | inode = find_inode(sb, head, test, data); | |
797 | if (inode) { | |
798 | __iget(inode); | |
799 | spin_unlock(&inode_lock); | |
88bd5121 AA |
800 | if (likely(wait)) |
801 | wait_on_inode(inode); | |
1da177e4 LT |
802 | return inode; |
803 | } | |
804 | spin_unlock(&inode_lock); | |
805 | return NULL; | |
806 | } | |
807 | ||
808 | /** | |
809 | * ifind_fast - internal function, you want ilookup() or iget(). | |
810 | * @sb: super block of file system to search | |
811 | * @head: head of the list to search | |
812 | * @ino: inode number to search for | |
813 | * | |
814 | * ifind_fast() searches for the inode @ino in the inode cache. This is for | |
815 | * file systems where the inode number is sufficient for unique identification | |
816 | * of an inode. | |
817 | * | |
818 | * If the inode is in the cache, the inode is returned with an incremented | |
819 | * reference count. | |
820 | * | |
821 | * Otherwise NULL is returned. | |
822 | */ | |
5d2bea45 | 823 | static struct inode *ifind_fast(struct super_block *sb, |
1da177e4 LT |
824 | struct hlist_head *head, unsigned long ino) |
825 | { | |
826 | struct inode *inode; | |
827 | ||
828 | spin_lock(&inode_lock); | |
829 | inode = find_inode_fast(sb, head, ino); | |
830 | if (inode) { | |
831 | __iget(inode); | |
832 | spin_unlock(&inode_lock); | |
833 | wait_on_inode(inode); | |
834 | return inode; | |
835 | } | |
836 | spin_unlock(&inode_lock); | |
837 | return NULL; | |
838 | } | |
839 | ||
840 | /** | |
88bd5121 | 841 | * ilookup5_nowait - search for an inode in the inode cache |
1da177e4 LT |
842 | * @sb: super block of file system to search |
843 | * @hashval: hash value (usually inode number) to search for | |
844 | * @test: callback used for comparisons between inodes | |
845 | * @data: opaque data pointer to pass to @test | |
846 | * | |
847 | * ilookup5() uses ifind() to search for the inode specified by @hashval and | |
848 | * @data in the inode cache. This is a generalized version of ilookup() for | |
849 | * file systems where the inode number is not sufficient for unique | |
850 | * identification of an inode. | |
851 | * | |
852 | * If the inode is in the cache, the inode is returned with an incremented | |
88bd5121 AA |
853 | * reference count. Note, the inode lock is not waited upon so you have to be |
854 | * very careful what you do with the returned inode. You probably should be | |
855 | * using ilookup5() instead. | |
856 | * | |
857 | * Otherwise NULL is returned. | |
858 | * | |
859 | * Note, @test is called with the inode_lock held, so can't sleep. | |
860 | */ | |
861 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, | |
862 | int (*test)(struct inode *, void *), void *data) | |
863 | { | |
864 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
865 | ||
866 | return ifind(sb, head, test, data, 0); | |
867 | } | |
868 | ||
869 | EXPORT_SYMBOL(ilookup5_nowait); | |
870 | ||
871 | /** | |
872 | * ilookup5 - search for an inode in the inode cache | |
873 | * @sb: super block of file system to search | |
874 | * @hashval: hash value (usually inode number) to search for | |
875 | * @test: callback used for comparisons between inodes | |
876 | * @data: opaque data pointer to pass to @test | |
877 | * | |
878 | * ilookup5() uses ifind() to search for the inode specified by @hashval and | |
879 | * @data in the inode cache. This is a generalized version of ilookup() for | |
880 | * file systems where the inode number is not sufficient for unique | |
881 | * identification of an inode. | |
882 | * | |
883 | * If the inode is in the cache, the inode lock is waited upon and the inode is | |
884 | * returned with an incremented reference count. | |
1da177e4 LT |
885 | * |
886 | * Otherwise NULL is returned. | |
887 | * | |
888 | * Note, @test is called with the inode_lock held, so can't sleep. | |
889 | */ | |
890 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, | |
891 | int (*test)(struct inode *, void *), void *data) | |
892 | { | |
893 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
894 | ||
88bd5121 | 895 | return ifind(sb, head, test, data, 1); |
1da177e4 LT |
896 | } |
897 | ||
898 | EXPORT_SYMBOL(ilookup5); | |
899 | ||
900 | /** | |
901 | * ilookup - search for an inode in the inode cache | |
902 | * @sb: super block of file system to search | |
903 | * @ino: inode number to search for | |
904 | * | |
905 | * ilookup() uses ifind_fast() to search for the inode @ino in the inode cache. | |
906 | * This is for file systems where the inode number is sufficient for unique | |
907 | * identification of an inode. | |
908 | * | |
909 | * If the inode is in the cache, the inode is returned with an incremented | |
910 | * reference count. | |
911 | * | |
912 | * Otherwise NULL is returned. | |
913 | */ | |
914 | struct inode *ilookup(struct super_block *sb, unsigned long ino) | |
915 | { | |
916 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
917 | ||
918 | return ifind_fast(sb, head, ino); | |
919 | } | |
920 | ||
921 | EXPORT_SYMBOL(ilookup); | |
922 | ||
923 | /** | |
924 | * iget5_locked - obtain an inode from a mounted file system | |
925 | * @sb: super block of file system | |
926 | * @hashval: hash value (usually inode number) to get | |
927 | * @test: callback used for comparisons between inodes | |
928 | * @set: callback used to initialize a new struct inode | |
929 | * @data: opaque data pointer to pass to @test and @set | |
930 | * | |
1da177e4 LT |
931 | * iget5_locked() uses ifind() to search for the inode specified by @hashval |
932 | * and @data in the inode cache and if present it is returned with an increased | |
933 | * reference count. This is a generalized version of iget_locked() for file | |
934 | * systems where the inode number is not sufficient for unique identification | |
935 | * of an inode. | |
936 | * | |
937 | * If the inode is not in cache, get_new_inode() is called to allocate a new | |
938 | * inode and this is returned locked, hashed, and with the I_NEW flag set. The | |
939 | * file system gets to fill it in before unlocking it via unlock_new_inode(). | |
940 | * | |
941 | * Note both @test and @set are called with the inode_lock held, so can't sleep. | |
942 | */ | |
943 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, | |
944 | int (*test)(struct inode *, void *), | |
945 | int (*set)(struct inode *, void *), void *data) | |
946 | { | |
947 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); | |
948 | struct inode *inode; | |
949 | ||
88bd5121 | 950 | inode = ifind(sb, head, test, data, 1); |
1da177e4 LT |
951 | if (inode) |
952 | return inode; | |
953 | /* | |
954 | * get_new_inode() will do the right thing, re-trying the search | |
955 | * in case it had to block at any point. | |
956 | */ | |
957 | return get_new_inode(sb, head, test, set, data); | |
958 | } | |
959 | ||
960 | EXPORT_SYMBOL(iget5_locked); | |
961 | ||
962 | /** | |
963 | * iget_locked - obtain an inode from a mounted file system | |
964 | * @sb: super block of file system | |
965 | * @ino: inode number to get | |
966 | * | |
1da177e4 LT |
967 | * iget_locked() uses ifind_fast() to search for the inode specified by @ino in |
968 | * the inode cache and if present it is returned with an increased reference | |
969 | * count. This is for file systems where the inode number is sufficient for | |
970 | * unique identification of an inode. | |
971 | * | |
972 | * If the inode is not in cache, get_new_inode_fast() is called to allocate a | |
973 | * new inode and this is returned locked, hashed, and with the I_NEW flag set. | |
974 | * The file system gets to fill it in before unlocking it via | |
975 | * unlock_new_inode(). | |
976 | */ | |
977 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) | |
978 | { | |
979 | struct hlist_head *head = inode_hashtable + hash(sb, ino); | |
980 | struct inode *inode; | |
981 | ||
982 | inode = ifind_fast(sb, head, ino); | |
983 | if (inode) | |
984 | return inode; | |
985 | /* | |
986 | * get_new_inode_fast() will do the right thing, re-trying the search | |
987 | * in case it had to block at any point. | |
988 | */ | |
989 | return get_new_inode_fast(sb, head, ino); | |
990 | } | |
991 | ||
992 | EXPORT_SYMBOL(iget_locked); | |
993 | ||
994 | /** | |
995 | * __insert_inode_hash - hash an inode | |
996 | * @inode: unhashed inode | |
997 | * @hashval: unsigned long value used to locate this object in the | |
998 | * inode_hashtable. | |
999 | * | |
1000 | * Add an inode to the inode hash for this superblock. | |
1001 | */ | |
1002 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) | |
1003 | { | |
1004 | struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); | |
1005 | spin_lock(&inode_lock); | |
1006 | hlist_add_head(&inode->i_hash, head); | |
1007 | spin_unlock(&inode_lock); | |
1008 | } | |
1009 | ||
1010 | EXPORT_SYMBOL(__insert_inode_hash); | |
1011 | ||
1012 | /** | |
1013 | * remove_inode_hash - remove an inode from the hash | |
1014 | * @inode: inode to unhash | |
1015 | * | |
1016 | * Remove an inode from the superblock. | |
1017 | */ | |
1018 | void remove_inode_hash(struct inode *inode) | |
1019 | { | |
1020 | spin_lock(&inode_lock); | |
1021 | hlist_del_init(&inode->i_hash); | |
1022 | spin_unlock(&inode_lock); | |
1023 | } | |
1024 | ||
1025 | EXPORT_SYMBOL(remove_inode_hash); | |
1026 | ||
1027 | /* | |
1028 | * Tell the filesystem that this inode is no longer of any interest and should | |
1029 | * be completely destroyed. | |
1030 | * | |
1031 | * We leave the inode in the inode hash table until *after* the filesystem's | |
1032 | * ->delete_inode completes. This ensures that an iget (such as nfsd might | |
1033 | * instigate) will always find up-to-date information either in the hash or on | |
1034 | * disk. | |
1035 | * | |
1036 | * I_FREEING is set so that no-one will take a new reference to the inode while | |
1037 | * it is being deleted. | |
1038 | */ | |
1039 | void generic_delete_inode(struct inode *inode) | |
1040 | { | |
ee9b6d61 | 1041 | const struct super_operations *op = inode->i_sb->s_op; |
1da177e4 LT |
1042 | |
1043 | list_del_init(&inode->i_list); | |
1044 | list_del_init(&inode->i_sb_list); | |
ed97bd37 | 1045 | inode->i_state |= I_FREEING; |
1da177e4 LT |
1046 | inodes_stat.nr_inodes--; |
1047 | spin_unlock(&inode_lock); | |
1048 | ||
1da177e4 LT |
1049 | security_inode_delete(inode); |
1050 | ||
1051 | if (op->delete_inode) { | |
1052 | void (*delete)(struct inode *) = op->delete_inode; | |
1053 | if (!is_bad_inode(inode)) | |
1054 | DQUOT_INIT(inode); | |
e85b5652 MF |
1055 | /* Filesystems implementing their own |
1056 | * s_op->delete_inode are required to call | |
1057 | * truncate_inode_pages and clear_inode() | |
1058 | * internally */ | |
1da177e4 | 1059 | delete(inode); |
e85b5652 MF |
1060 | } else { |
1061 | truncate_inode_pages(&inode->i_data, 0); | |
1da177e4 | 1062 | clear_inode(inode); |
e85b5652 | 1063 | } |
1da177e4 LT |
1064 | spin_lock(&inode_lock); |
1065 | hlist_del_init(&inode->i_hash); | |
1066 | spin_unlock(&inode_lock); | |
1067 | wake_up_inode(inode); | |
b7542f8c | 1068 | BUG_ON(inode->i_state != I_CLEAR); |
1da177e4 LT |
1069 | destroy_inode(inode); |
1070 | } | |
1071 | ||
1072 | EXPORT_SYMBOL(generic_delete_inode); | |
1073 | ||
1074 | static void generic_forget_inode(struct inode *inode) | |
1075 | { | |
1076 | struct super_block *sb = inode->i_sb; | |
1077 | ||
1078 | if (!hlist_unhashed(&inode->i_hash)) { | |
1c0eeaf5 | 1079 | if (!(inode->i_state & (I_DIRTY|I_SYNC))) |
1da177e4 LT |
1080 | list_move(&inode->i_list, &inode_unused); |
1081 | inodes_stat.nr_unused++; | |
acb0c854 | 1082 | if (sb->s_flags & MS_ACTIVE) { |
991114c6 | 1083 | spin_unlock(&inode_lock); |
1da177e4 | 1084 | return; |
991114c6 AV |
1085 | } |
1086 | inode->i_state |= I_WILL_FREE; | |
1087 | spin_unlock(&inode_lock); | |
1da177e4 LT |
1088 | write_inode_now(inode, 1); |
1089 | spin_lock(&inode_lock); | |
991114c6 | 1090 | inode->i_state &= ~I_WILL_FREE; |
1da177e4 LT |
1091 | inodes_stat.nr_unused--; |
1092 | hlist_del_init(&inode->i_hash); | |
1093 | } | |
1094 | list_del_init(&inode->i_list); | |
1095 | list_del_init(&inode->i_sb_list); | |
991114c6 | 1096 | inode->i_state |= I_FREEING; |
1da177e4 LT |
1097 | inodes_stat.nr_inodes--; |
1098 | spin_unlock(&inode_lock); | |
1099 | if (inode->i_data.nrpages) | |
1100 | truncate_inode_pages(&inode->i_data, 0); | |
1101 | clear_inode(inode); | |
7f04c26d | 1102 | wake_up_inode(inode); |
1da177e4 LT |
1103 | destroy_inode(inode); |
1104 | } | |
1105 | ||
1106 | /* | |
1107 | * Normal UNIX filesystem behaviour: delete the | |
1108 | * inode when the usage count drops to zero, and | |
1109 | * i_nlink is zero. | |
1110 | */ | |
cb2c0233 | 1111 | void generic_drop_inode(struct inode *inode) |
1da177e4 LT |
1112 | { |
1113 | if (!inode->i_nlink) | |
1114 | generic_delete_inode(inode); | |
1115 | else | |
1116 | generic_forget_inode(inode); | |
1117 | } | |
1118 | ||
cb2c0233 MF |
1119 | EXPORT_SYMBOL_GPL(generic_drop_inode); |
1120 | ||
1da177e4 LT |
1121 | /* |
1122 | * Called when we're dropping the last reference | |
1123 | * to an inode. | |
1124 | * | |
1125 | * Call the FS "drop()" function, defaulting to | |
1126 | * the legacy UNIX filesystem behaviour.. | |
1127 | * | |
1128 | * NOTE! NOTE! NOTE! We're called with the inode lock | |
1129 | * held, and the drop function is supposed to release | |
1130 | * the lock! | |
1131 | */ | |
1132 | static inline void iput_final(struct inode *inode) | |
1133 | { | |
ee9b6d61 | 1134 | const struct super_operations *op = inode->i_sb->s_op; |
1da177e4 LT |
1135 | void (*drop)(struct inode *) = generic_drop_inode; |
1136 | ||
1137 | if (op && op->drop_inode) | |
1138 | drop = op->drop_inode; | |
1139 | drop(inode); | |
1140 | } | |
1141 | ||
1142 | /** | |
1143 | * iput - put an inode | |
1144 | * @inode: inode to put | |
1145 | * | |
1146 | * Puts an inode, dropping its usage count. If the inode use count hits | |
1147 | * zero, the inode is then freed and may also be destroyed. | |
1148 | * | |
1149 | * Consequently, iput() can sleep. | |
1150 | */ | |
1151 | void iput(struct inode *inode) | |
1152 | { | |
1153 | if (inode) { | |
ee9b6d61 | 1154 | const struct super_operations *op = inode->i_sb->s_op; |
1da177e4 LT |
1155 | |
1156 | BUG_ON(inode->i_state == I_CLEAR); | |
1157 | ||
1158 | if (op && op->put_inode) | |
1159 | op->put_inode(inode); | |
1160 | ||
1161 | if (atomic_dec_and_lock(&inode->i_count, &inode_lock)) | |
1162 | iput_final(inode); | |
1163 | } | |
1164 | } | |
1165 | ||
1166 | EXPORT_SYMBOL(iput); | |
1167 | ||
1168 | /** | |
1169 | * bmap - find a block number in a file | |
1170 | * @inode: inode of file | |
1171 | * @block: block to find | |
1172 | * | |
1173 | * Returns the block number on the device holding the inode that | |
1174 | * is the disk block number for the block of the file requested. | |
1175 | * That is, asked for block 4 of inode 1 the function will return the | |
1176 | * disk block relative to the disk start that holds that block of the | |
1177 | * file. | |
1178 | */ | |
1179 | sector_t bmap(struct inode * inode, sector_t block) | |
1180 | { | |
1181 | sector_t res = 0; | |
1182 | if (inode->i_mapping->a_ops->bmap) | |
1183 | res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block); | |
1184 | return res; | |
1185 | } | |
1da177e4 LT |
1186 | EXPORT_SYMBOL(bmap); |
1187 | ||
1188 | /** | |
869243a0 CH |
1189 | * touch_atime - update the access time |
1190 | * @mnt: mount the inode is accessed on | |
7045f37b | 1191 | * @dentry: dentry accessed |
1da177e4 LT |
1192 | * |
1193 | * Update the accessed time on an inode and mark it for writeback. | |
1194 | * This function automatically handles read only file systems and media, | |
1195 | * as well as the "noatime" flag and inode specific "noatime" markers. | |
1196 | */ | |
869243a0 | 1197 | void touch_atime(struct vfsmount *mnt, struct dentry *dentry) |
1da177e4 | 1198 | { |
869243a0 | 1199 | struct inode *inode = dentry->d_inode; |
1da177e4 LT |
1200 | struct timespec now; |
1201 | ||
b2276138 AM |
1202 | if (inode->i_flags & S_NOATIME) |
1203 | return; | |
37756ced | 1204 | if (IS_NOATIME(inode)) |
b2276138 AM |
1205 | return; |
1206 | if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode)) | |
1da177e4 | 1207 | return; |
fc33a7bb CH |
1208 | |
1209 | /* | |
1210 | * We may have a NULL vfsmount when coming from NFSD | |
1211 | */ | |
b2276138 AM |
1212 | if (mnt) { |
1213 | if (mnt->mnt_flags & MNT_NOATIME) | |
1214 | return; | |
1215 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) | |
1216 | return; | |
47ae32d6 VH |
1217 | |
1218 | if (mnt->mnt_flags & MNT_RELATIME) { | |
1219 | /* | |
1220 | * With relative atime, only update atime if the | |
1221 | * previous atime is earlier than either the ctime or | |
1222 | * mtime. | |
1223 | */ | |
1224 | if (timespec_compare(&inode->i_mtime, | |
1225 | &inode->i_atime) < 0 && | |
1226 | timespec_compare(&inode->i_ctime, | |
1227 | &inode->i_atime) < 0) | |
1228 | return; | |
1229 | } | |
b2276138 | 1230 | } |
1da177e4 LT |
1231 | |
1232 | now = current_fs_time(inode->i_sb); | |
47ae32d6 VH |
1233 | if (timespec_equal(&inode->i_atime, &now)) |
1234 | return; | |
1235 | ||
1236 | inode->i_atime = now; | |
1237 | mark_inode_dirty_sync(inode); | |
1da177e4 | 1238 | } |
869243a0 | 1239 | EXPORT_SYMBOL(touch_atime); |
1da177e4 LT |
1240 | |
1241 | /** | |
870f4817 CH |
1242 | * file_update_time - update mtime and ctime time |
1243 | * @file: file accessed | |
1da177e4 | 1244 | * |
870f4817 CH |
1245 | * Update the mtime and ctime members of an inode and mark the inode |
1246 | * for writeback. Note that this function is meant exclusively for | |
1247 | * usage in the file write path of filesystems, and filesystems may | |
1248 | * choose to explicitly ignore update via this function with the | |
1249 | * S_NOCTIME inode flag, e.g. for network filesystem where these | |
1250 | * timestamps are handled by the server. | |
1da177e4 LT |
1251 | */ |
1252 | ||
870f4817 | 1253 | void file_update_time(struct file *file) |
1da177e4 | 1254 | { |
0f7fc9e4 | 1255 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1256 | struct timespec now; |
1257 | int sync_it = 0; | |
1258 | ||
1259 | if (IS_NOCMTIME(inode)) | |
1260 | return; | |
1261 | if (IS_RDONLY(inode)) | |
1262 | return; | |
1263 | ||
1264 | now = current_fs_time(inode->i_sb); | |
ed97bd37 AM |
1265 | if (!timespec_equal(&inode->i_mtime, &now)) { |
1266 | inode->i_mtime = now; | |
1da177e4 | 1267 | sync_it = 1; |
ed97bd37 | 1268 | } |
1da177e4 | 1269 | |
ed97bd37 AM |
1270 | if (!timespec_equal(&inode->i_ctime, &now)) { |
1271 | inode->i_ctime = now; | |
870f4817 | 1272 | sync_it = 1; |
ed97bd37 | 1273 | } |
870f4817 | 1274 | |
7a224228 JNC |
1275 | if (IS_I_VERSION(inode)) { |
1276 | inode_inc_iversion(inode); | |
1277 | sync_it = 1; | |
1278 | } | |
1279 | ||
1da177e4 LT |
1280 | if (sync_it) |
1281 | mark_inode_dirty_sync(inode); | |
1282 | } | |
1283 | ||
870f4817 | 1284 | EXPORT_SYMBOL(file_update_time); |
1da177e4 LT |
1285 | |
1286 | int inode_needs_sync(struct inode *inode) | |
1287 | { | |
1288 | if (IS_SYNC(inode)) | |
1289 | return 1; | |
1290 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) | |
1291 | return 1; | |
1292 | return 0; | |
1293 | } | |
1294 | ||
1295 | EXPORT_SYMBOL(inode_needs_sync); | |
1296 | ||
1da177e4 LT |
1297 | int inode_wait(void *word) |
1298 | { | |
1299 | schedule(); | |
1300 | return 0; | |
1301 | } | |
1302 | ||
1303 | /* | |
168a9fd6 MS |
1304 | * If we try to find an inode in the inode hash while it is being |
1305 | * deleted, we have to wait until the filesystem completes its | |
1306 | * deletion before reporting that it isn't found. This function waits | |
1307 | * until the deletion _might_ have completed. Callers are responsible | |
1308 | * to recheck inode state. | |
1309 | * | |
1310 | * It doesn't matter if I_LOCK is not set initially, a call to | |
1311 | * wake_up_inode() after removing from the hash list will DTRT. | |
1312 | * | |
1da177e4 LT |
1313 | * This is called with inode_lock held. |
1314 | */ | |
1315 | static void __wait_on_freeing_inode(struct inode *inode) | |
1316 | { | |
1317 | wait_queue_head_t *wq; | |
1318 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK); | |
1da177e4 LT |
1319 | wq = bit_waitqueue(&inode->i_state, __I_LOCK); |
1320 | prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); | |
1321 | spin_unlock(&inode_lock); | |
1322 | schedule(); | |
1323 | finish_wait(wq, &wait.wait); | |
1324 | spin_lock(&inode_lock); | |
1325 | } | |
1326 | ||
62752ee1 MF |
1327 | /* |
1328 | * We rarely want to lock two inodes that do not have a parent/child | |
1329 | * relationship (such as directory, child inode) simultaneously. The | |
1330 | * vast majority of file systems should be able to get along fine | |
1331 | * without this. Do not use these functions except as a last resort. | |
1332 | */ | |
1333 | void inode_double_lock(struct inode *inode1, struct inode *inode2) | |
1334 | { | |
1335 | if (inode1 == NULL || inode2 == NULL || inode1 == inode2) { | |
1336 | if (inode1) | |
1337 | mutex_lock(&inode1->i_mutex); | |
1338 | else if (inode2) | |
1339 | mutex_lock(&inode2->i_mutex); | |
1340 | return; | |
1341 | } | |
1342 | ||
1343 | if (inode1 < inode2) { | |
1344 | mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT); | |
1345 | mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD); | |
1346 | } else { | |
1347 | mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT); | |
1348 | mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD); | |
1349 | } | |
1350 | } | |
1351 | EXPORT_SYMBOL(inode_double_lock); | |
1352 | ||
1353 | void inode_double_unlock(struct inode *inode1, struct inode *inode2) | |
1354 | { | |
1355 | if (inode1) | |
1356 | mutex_unlock(&inode1->i_mutex); | |
1357 | ||
1358 | if (inode2 && inode2 != inode1) | |
1359 | mutex_unlock(&inode2->i_mutex); | |
1360 | } | |
1361 | EXPORT_SYMBOL(inode_double_unlock); | |
1362 | ||
1da177e4 LT |
1363 | static __initdata unsigned long ihash_entries; |
1364 | static int __init set_ihash_entries(char *str) | |
1365 | { | |
1366 | if (!str) | |
1367 | return 0; | |
1368 | ihash_entries = simple_strtoul(str, &str, 0); | |
1369 | return 1; | |
1370 | } | |
1371 | __setup("ihash_entries=", set_ihash_entries); | |
1372 | ||
1373 | /* | |
1374 | * Initialize the waitqueues and inode hash table. | |
1375 | */ | |
1376 | void __init inode_init_early(void) | |
1377 | { | |
1378 | int loop; | |
1379 | ||
1380 | /* If hashes are distributed across NUMA nodes, defer | |
1381 | * hash allocation until vmalloc space is available. | |
1382 | */ | |
1383 | if (hashdist) | |
1384 | return; | |
1385 | ||
1386 | inode_hashtable = | |
1387 | alloc_large_system_hash("Inode-cache", | |
1388 | sizeof(struct hlist_head), | |
1389 | ihash_entries, | |
1390 | 14, | |
1391 | HASH_EARLY, | |
1392 | &i_hash_shift, | |
1393 | &i_hash_mask, | |
1394 | 0); | |
1395 | ||
1396 | for (loop = 0; loop < (1 << i_hash_shift); loop++) | |
1397 | INIT_HLIST_HEAD(&inode_hashtable[loop]); | |
1398 | } | |
1399 | ||
74bf17cf | 1400 | void __init inode_init(void) |
1da177e4 LT |
1401 | { |
1402 | int loop; | |
1403 | ||
1404 | /* inode slab cache */ | |
b0196009 PJ |
1405 | inode_cachep = kmem_cache_create("inode_cache", |
1406 | sizeof(struct inode), | |
1407 | 0, | |
1408 | (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| | |
1409 | SLAB_MEM_SPREAD), | |
20c2df83 | 1410 | init_once); |
8e1f936b | 1411 | register_shrinker(&icache_shrinker); |
1da177e4 LT |
1412 | |
1413 | /* Hash may have been set up in inode_init_early */ | |
1414 | if (!hashdist) | |
1415 | return; | |
1416 | ||
1417 | inode_hashtable = | |
1418 | alloc_large_system_hash("Inode-cache", | |
1419 | sizeof(struct hlist_head), | |
1420 | ihash_entries, | |
1421 | 14, | |
1422 | 0, | |
1423 | &i_hash_shift, | |
1424 | &i_hash_mask, | |
1425 | 0); | |
1426 | ||
1427 | for (loop = 0; loop < (1 << i_hash_shift); loop++) | |
1428 | INIT_HLIST_HEAD(&inode_hashtable[loop]); | |
1429 | } | |
1430 | ||
1431 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) | |
1432 | { | |
1433 | inode->i_mode = mode; | |
1434 | if (S_ISCHR(mode)) { | |
1435 | inode->i_fop = &def_chr_fops; | |
1436 | inode->i_rdev = rdev; | |
1437 | } else if (S_ISBLK(mode)) { | |
1438 | inode->i_fop = &def_blk_fops; | |
1439 | inode->i_rdev = rdev; | |
1440 | } else if (S_ISFIFO(mode)) | |
1441 | inode->i_fop = &def_fifo_fops; | |
1442 | else if (S_ISSOCK(mode)) | |
1443 | inode->i_fop = &bad_sock_fops; | |
1444 | else | |
1445 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n", | |
1446 | mode); | |
1447 | } | |
1448 | EXPORT_SYMBOL(init_special_inode); |