1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * (C) 1997 Linus Torvalds |
4 | * (C) 1999 Andrea Arcangeli <andrea@suse.de> (dynamic inode allocation) |
5 | */ |
6 | #include <linux/export.h> |
7 | #include <linux/fs.h> |
8 | #include <linux/filelock.h> |
9 | #include <linux/mm.h> |
10 | #include <linux/backing-dev.h> |
11 | #include <linux/hash.h> |
12 | #include <linux/swap.h> |
13 | #include <linux/security.h> |
14 | #include <linux/cdev.h> |
15 | #include <linux/memblock.h> |
16 | #include <linux/fsnotify.h> |
17 | #include <linux/mount.h> |
18 | #include <linux/posix_acl.h> |
19 | #include <linux/buffer_head.h> /* for inode_has_buffers */ |
20 | #include <linux/ratelimit.h> |
21 | #include <linux/list_lru.h> |
22 | #include <linux/iversion.h> |
23 | #include <trace/events/writeback.h> |
24 | #include "internal.h" |
25 | |
26 | /* |
27 | * Inode locking rules: |
28 | * |
29 | * inode->i_lock protects: |
30 | * inode->i_state, inode->i_hash, __iget(), inode->i_io_list |
31 | * Inode LRU list locks protect: |
32 | * inode->i_sb->s_inode_lru, inode->i_lru |
33 | * inode->i_sb->s_inode_list_lock protects: |
34 | * inode->i_sb->s_inodes, inode->i_sb_list |
35 | * bdi->wb.list_lock protects: |
36 | * bdi->wb.b_{dirty,io,more_io,dirty_time}, inode->i_io_list |
37 | * inode_hash_lock protects: |
38 | * inode_hashtable, inode->i_hash |
39 | * |
40 | * Lock ordering: |
41 | * |
42 | * inode->i_sb->s_inode_list_lock |
43 | * inode->i_lock |
44 | * Inode LRU list locks |
45 | * |
46 | * bdi->wb.list_lock |
47 | * inode->i_lock |
48 | * |
49 | * inode_hash_lock |
50 | * inode->i_sb->s_inode_list_lock |
51 | * inode->i_lock |
52 | * |
53 | * iunique_lock |
54 | * inode_hash_lock |
55 | */ |
56 | |
57 | static unsigned int i_hash_mask __ro_after_init; |
58 | static unsigned int i_hash_shift __ro_after_init; |
59 | static struct hlist_head *inode_hashtable __ro_after_init; |
60 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock); |
61 | |
62 | /* |
63 | * Empty aops. Can be used for the cases where the user does not |
64 | * define any of the address_space operations. |
65 | */ |
66 | const struct address_space_operations empty_aops = { |
67 | }; |
68 | EXPORT_SYMBOL(empty_aops); |
69 | |
70 | static DEFINE_PER_CPU(unsigned long, nr_inodes); |
71 | static DEFINE_PER_CPU(unsigned long, nr_unused); |
72 | |
73 | static struct kmem_cache *inode_cachep __ro_after_init; |
74 | |
75 | static long get_nr_inodes(void) |
76 | { |
77 | int i; |
78 | long sum = 0; |
79 | for_each_possible_cpu(i) |
80 | sum += per_cpu(nr_inodes, i); |
81 | return sum < 0 ? 0 : sum; |
82 | } |
83 | |
84 | static inline long get_nr_inodes_unused(void) |
85 | { |
86 | int i; |
87 | long sum = 0; |
88 | for_each_possible_cpu(i) |
89 | sum += per_cpu(nr_unused, i); |
90 | return sum < 0 ? 0 : sum; |
91 | } |
92 | |
93 | long get_nr_dirty_inodes(void) |
94 | { |
95 | /* not actually dirty inodes, but a wild approximation */ |
96 | long nr_dirty = get_nr_inodes() - get_nr_inodes_unused(); |
97 | return nr_dirty > 0 ? nr_dirty : 0; |
98 | } |
99 | |
100 | /* |
101 | * Handle nr_inode sysctl |
102 | */ |
103 | #ifdef CONFIG_SYSCTL |
104 | /* |
105 | * Statistics gathering.. |
106 | */ |
107 | static struct inodes_stat_t inodes_stat; |
108 | |
109 | static int proc_nr_inodes(struct ctl_table *table, int write, void *buffer, |
110 | size_t *lenp, loff_t *ppos) |
111 | { |
112 | inodes_stat.nr_inodes = get_nr_inodes(); |
113 | inodes_stat.nr_unused = get_nr_inodes_unused(); |
114 | return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); |
115 | } |
116 | |
117 | static struct ctl_table inodes_sysctls[] = { |
118 | { |
119 | .procname = "inode-nr" , |
120 | .data = &inodes_stat, |
121 | .maxlen = 2*sizeof(long), |
122 | .mode = 0444, |
123 | .proc_handler = proc_nr_inodes, |
124 | }, |
125 | { |
126 | .procname = "inode-state" , |
127 | .data = &inodes_stat, |
128 | .maxlen = 7*sizeof(long), |
129 | .mode = 0444, |
130 | .proc_handler = proc_nr_inodes, |
131 | }, |
132 | { } |
133 | }; |
134 | |
135 | static int __init init_fs_inode_sysctls(void) |
136 | { |
137 | register_sysctl_init("fs" , inodes_sysctls); |
138 | return 0; |
139 | } |
140 | early_initcall(init_fs_inode_sysctls); |
141 | #endif |
142 | |
143 | static int no_open(struct inode *inode, struct file *file) |
144 | { |
145 | return -ENXIO; |
146 | } |
147 | |
148 | /** |
149 | * inode_init_always - perform inode structure initialisation |
150 | * @sb: superblock inode belongs to |
151 | * @inode: inode to initialise |
152 | * |
153 | * These are initializations that need to be done on every inode |
154 | * allocation as the fields are not initialised by slab allocation. |
155 | */ |
156 | int inode_init_always(struct super_block *sb, struct inode *inode) |
157 | { |
158 | static const struct inode_operations empty_iops; |
159 | static const struct file_operations no_open_fops = {.open = no_open}; |
160 | struct address_space *const mapping = &inode->i_data; |
161 | |
162 | inode->i_sb = sb; |
163 | inode->i_blkbits = sb->s_blocksize_bits; |
164 | inode->i_flags = 0; |
165 | atomic64_set(v: &inode->i_sequence, i: 0); |
166 | atomic_set(v: &inode->i_count, i: 1); |
167 | inode->i_op = &empty_iops; |
168 | inode->i_fop = &no_open_fops; |
169 | inode->i_ino = 0; |
170 | inode->__i_nlink = 1; |
171 | inode->i_opflags = 0; |
172 | if (sb->s_xattr) |
173 | inode->i_opflags |= IOP_XATTR; |
174 | i_uid_write(inode, uid: 0); |
175 | i_gid_write(inode, gid: 0); |
176 | atomic_set(v: &inode->i_writecount, i: 0); |
177 | inode->i_size = 0; |
178 | inode->i_write_hint = WRITE_LIFE_NOT_SET; |
179 | inode->i_blocks = 0; |
180 | inode->i_bytes = 0; |
181 | inode->i_generation = 0; |
182 | inode->i_pipe = NULL; |
183 | inode->i_cdev = NULL; |
184 | inode->i_link = NULL; |
185 | inode->i_dir_seq = 0; |
186 | inode->i_rdev = 0; |
187 | inode->dirtied_when = 0; |
188 | |
189 | #ifdef CONFIG_CGROUP_WRITEBACK |
190 | inode->i_wb_frn_winner = 0; |
191 | inode->i_wb_frn_avg_time = 0; |
192 | inode->i_wb_frn_history = 0; |
193 | #endif |
194 | |
195 | spin_lock_init(&inode->i_lock); |
196 | lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); |
197 | |
198 | init_rwsem(&inode->i_rwsem); |
199 | lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); |
200 | |
201 | atomic_set(v: &inode->i_dio_count, i: 0); |
202 | |
203 | mapping->a_ops = &empty_aops; |
204 | mapping->host = inode; |
205 | mapping->flags = 0; |
206 | mapping->wb_err = 0; |
207 | atomic_set(v: &mapping->i_mmap_writable, i: 0); |
208 | #ifdef CONFIG_READ_ONLY_THP_FOR_FS |
209 | atomic_set(v: &mapping->nr_thps, i: 0); |
210 | #endif |
211 | mapping_set_gfp_mask(m: mapping, GFP_HIGHUSER_MOVABLE); |
212 | mapping->private_data = NULL; |
213 | mapping->writeback_index = 0; |
214 | init_rwsem(&mapping->invalidate_lock); |
215 | lockdep_set_class_and_name(&mapping->invalidate_lock, |
216 | &sb->s_type->invalidate_lock_key, |
217 | "mapping.invalidate_lock" ); |
218 | inode->i_private = NULL; |
219 | inode->i_mapping = mapping; |
220 | INIT_HLIST_HEAD(&inode->i_dentry); /* buggered by rcu freeing */ |
221 | #ifdef CONFIG_FS_POSIX_ACL |
222 | inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED; |
223 | #endif |
224 | |
225 | #ifdef CONFIG_FSNOTIFY |
226 | inode->i_fsnotify_mask = 0; |
227 | #endif |
228 | inode->i_flctx = NULL; |
229 | |
230 | if (unlikely(security_inode_alloc(inode))) |
231 | return -ENOMEM; |
232 | this_cpu_inc(nr_inodes); |
233 | |
234 | return 0; |
235 | } |
236 | EXPORT_SYMBOL(inode_init_always); |
237 | |
238 | void free_inode_nonrcu(struct inode *inode) |
239 | { |
240 | kmem_cache_free(s: inode_cachep, objp: inode); |
241 | } |
242 | EXPORT_SYMBOL(free_inode_nonrcu); |
243 | |
244 | static void i_callback(struct rcu_head *head) |
245 | { |
246 | struct inode *inode = container_of(head, struct inode, i_rcu); |
247 | if (inode->free_inode) |
248 | inode->free_inode(inode); |
249 | else |
250 | free_inode_nonrcu(inode); |
251 | } |
252 | |
253 | static struct inode *alloc_inode(struct super_block *sb) |
254 | { |
255 | const struct super_operations *ops = sb->s_op; |
256 | struct inode *inode; |
257 | |
258 | if (ops->alloc_inode) |
259 | inode = ops->alloc_inode(sb); |
260 | else |
261 | inode = alloc_inode_sb(sb, cache: inode_cachep, GFP_KERNEL); |
262 | |
263 | if (!inode) |
264 | return NULL; |
265 | |
266 | if (unlikely(inode_init_always(sb, inode))) { |
267 | if (ops->destroy_inode) { |
268 | ops->destroy_inode(inode); |
269 | if (!ops->free_inode) |
270 | return NULL; |
271 | } |
272 | inode->free_inode = ops->free_inode; |
273 | i_callback(head: &inode->i_rcu); |
274 | return NULL; |
275 | } |
276 | |
277 | return inode; |
278 | } |
279 | |
280 | void __destroy_inode(struct inode *inode) |
281 | { |
282 | BUG_ON(inode_has_buffers(inode)); |
283 | inode_detach_wb(inode); |
284 | security_inode_free(inode); |
285 | fsnotify_inode_delete(inode); |
286 | locks_free_lock_context(inode); |
287 | if (!inode->i_nlink) { |
288 | WARN_ON(atomic_long_read(&inode->i_sb->s_remove_count) == 0); |
289 | atomic_long_dec(v: &inode->i_sb->s_remove_count); |
290 | } |
291 | |
292 | #ifdef CONFIG_FS_POSIX_ACL |
293 | if (inode->i_acl && !is_uncached_acl(acl: inode->i_acl)) |
294 | posix_acl_release(acl: inode->i_acl); |
295 | if (inode->i_default_acl && !is_uncached_acl(acl: inode->i_default_acl)) |
296 | posix_acl_release(acl: inode->i_default_acl); |
297 | #endif |
298 | this_cpu_dec(nr_inodes); |
299 | } |
300 | EXPORT_SYMBOL(__destroy_inode); |
301 | |
302 | static void destroy_inode(struct inode *inode) |
303 | { |
304 | const struct super_operations *ops = inode->i_sb->s_op; |
305 | |
306 | BUG_ON(!list_empty(&inode->i_lru)); |
307 | __destroy_inode(inode); |
308 | if (ops->destroy_inode) { |
309 | ops->destroy_inode(inode); |
310 | if (!ops->free_inode) |
311 | return; |
312 | } |
313 | inode->free_inode = ops->free_inode; |
314 | call_rcu(head: &inode->i_rcu, func: i_callback); |
315 | } |
316 | |
317 | /** |
318 | * drop_nlink - directly drop an inode's link count |
319 | * @inode: inode |
320 | * |
321 | * This is a low-level filesystem helper to replace any |
322 | * direct filesystem manipulation of i_nlink. In cases |
323 | * where we are attempting to track writes to the |
324 | * filesystem, a decrement to zero means an imminent |
325 | * write when the file is truncated and actually unlinked |
326 | * on the filesystem. |
327 | */ |
328 | void drop_nlink(struct inode *inode) |
329 | { |
330 | WARN_ON(inode->i_nlink == 0); |
331 | inode->__i_nlink--; |
332 | if (!inode->i_nlink) |
333 | atomic_long_inc(v: &inode->i_sb->s_remove_count); |
334 | } |
335 | EXPORT_SYMBOL(drop_nlink); |
336 | |
337 | /** |
338 | * clear_nlink - directly zero an inode's link count |
339 | * @inode: inode |
340 | * |
341 | * This is a low-level filesystem helper to replace any |
342 | * direct filesystem manipulation of i_nlink. See |
343 | * drop_nlink() for why we care about i_nlink hitting zero. |
344 | */ |
345 | void clear_nlink(struct inode *inode) |
346 | { |
347 | if (inode->i_nlink) { |
348 | inode->__i_nlink = 0; |
349 | atomic_long_inc(v: &inode->i_sb->s_remove_count); |
350 | } |
351 | } |
352 | EXPORT_SYMBOL(clear_nlink); |
353 | |
354 | /** |
355 | * set_nlink - directly set an inode's link count |
356 | * @inode: inode |
357 | * @nlink: new nlink (should be non-zero) |
358 | * |
359 | * This is a low-level filesystem helper to replace any |
360 | * direct filesystem manipulation of i_nlink. |
361 | */ |
362 | void set_nlink(struct inode *inode, unsigned int nlink) |
363 | { |
364 | if (!nlink) { |
365 | clear_nlink(inode); |
366 | } else { |
367 | /* Yes, some filesystems do change nlink from zero to one */ |
368 | if (inode->i_nlink == 0) |
369 | atomic_long_dec(v: &inode->i_sb->s_remove_count); |
370 | |
371 | inode->__i_nlink = nlink; |
372 | } |
373 | } |
374 | EXPORT_SYMBOL(set_nlink); |
375 | |
376 | /** |
377 | * inc_nlink - directly increment an inode's link count |
378 | * @inode: inode |
379 | * |
380 | * This is a low-level filesystem helper to replace any |
381 | * direct filesystem manipulation of i_nlink. Currently, |
382 | * it is only here for parity with dec_nlink(). |
383 | */ |
384 | void inc_nlink(struct inode *inode) |
385 | { |
386 | if (unlikely(inode->i_nlink == 0)) { |
387 | WARN_ON(!(inode->i_state & I_LINKABLE)); |
388 | atomic_long_dec(v: &inode->i_sb->s_remove_count); |
389 | } |
390 | |
391 | inode->__i_nlink++; |
392 | } |
393 | EXPORT_SYMBOL(inc_nlink); |
394 | |
395 | static void __address_space_init_once(struct address_space *mapping) |
396 | { |
397 | xa_init_flags(xa: &mapping->i_pages, XA_FLAGS_LOCK_IRQ | XA_FLAGS_ACCOUNT); |
398 | init_rwsem(&mapping->i_mmap_rwsem); |
399 | INIT_LIST_HEAD(list: &mapping->private_list); |
400 | spin_lock_init(&mapping->private_lock); |
401 | mapping->i_mmap = RB_ROOT_CACHED; |
402 | } |
403 | |
404 | void address_space_init_once(struct address_space *mapping) |
405 | { |
406 | memset(mapping, 0, sizeof(*mapping)); |
407 | __address_space_init_once(mapping); |
408 | } |
409 | EXPORT_SYMBOL(address_space_init_once); |
410 | |
411 | /* |
412 | * These are initializations that only need to be done |
413 | * once, because the fields are idempotent across use |
414 | * of the inode, so let the slab aware of that. |
415 | */ |
416 | void inode_init_once(struct inode *inode) |
417 | { |
418 | memset(inode, 0, sizeof(*inode)); |
419 | INIT_HLIST_NODE(h: &inode->i_hash); |
420 | INIT_LIST_HEAD(list: &inode->i_devices); |
421 | INIT_LIST_HEAD(list: &inode->i_io_list); |
422 | INIT_LIST_HEAD(list: &inode->i_wb_list); |
423 | INIT_LIST_HEAD(list: &inode->i_lru); |
424 | INIT_LIST_HEAD(list: &inode->i_sb_list); |
425 | __address_space_init_once(mapping: &inode->i_data); |
426 | i_size_ordered_init(inode); |
427 | } |
428 | EXPORT_SYMBOL(inode_init_once); |
429 | |
430 | static void init_once(void *foo) |
431 | { |
432 | struct inode *inode = (struct inode *) foo; |
433 | |
434 | inode_init_once(inode); |
435 | } |
436 | |
437 | /* |
438 | * inode->i_lock must be held |
439 | */ |
440 | void __iget(struct inode *inode) |
441 | { |
442 | atomic_inc(v: &inode->i_count); |
443 | } |
444 | |
445 | /* |
446 | * get additional reference to inode; caller must already hold one. |
447 | */ |
448 | void ihold(struct inode *inode) |
449 | { |
450 | WARN_ON(atomic_inc_return(&inode->i_count) < 2); |
451 | } |
452 | EXPORT_SYMBOL(ihold); |
453 | |
454 | static void __inode_add_lru(struct inode *inode, bool rotate) |
455 | { |
456 | if (inode->i_state & (I_DIRTY_ALL | I_SYNC | I_FREEING | I_WILL_FREE)) |
457 | return; |
458 | if (atomic_read(v: &inode->i_count)) |
459 | return; |
460 | if (!(inode->i_sb->s_flags & SB_ACTIVE)) |
461 | return; |
462 | if (!mapping_shrinkable(mapping: &inode->i_data)) |
463 | return; |
464 | |
465 | if (list_lru_add(lru: &inode->i_sb->s_inode_lru, item: &inode->i_lru)) |
466 | this_cpu_inc(nr_unused); |
467 | else if (rotate) |
468 | inode->i_state |= I_REFERENCED; |
469 | } |
470 | |
471 | /* |
472 | * Add inode to LRU if needed (inode is unused and clean). |
473 | * |
474 | * Needs inode->i_lock held. |
475 | */ |
476 | void inode_add_lru(struct inode *inode) |
477 | { |
478 | __inode_add_lru(inode, rotate: false); |
479 | } |
480 | |
481 | static void inode_lru_list_del(struct inode *inode) |
482 | { |
483 | if (list_lru_del(lru: &inode->i_sb->s_inode_lru, item: &inode->i_lru)) |
484 | this_cpu_dec(nr_unused); |
485 | } |
486 | |
487 | /** |
488 | * inode_sb_list_add - add inode to the superblock list of inodes |
489 | * @inode: inode to add |
490 | */ |
491 | void inode_sb_list_add(struct inode *inode) |
492 | { |
493 | spin_lock(lock: &inode->i_sb->s_inode_list_lock); |
494 | list_add(new: &inode->i_sb_list, head: &inode->i_sb->s_inodes); |
495 | spin_unlock(lock: &inode->i_sb->s_inode_list_lock); |
496 | } |
497 | EXPORT_SYMBOL_GPL(inode_sb_list_add); |
498 | |
499 | static inline void inode_sb_list_del(struct inode *inode) |
500 | { |
501 | if (!list_empty(head: &inode->i_sb_list)) { |
502 | spin_lock(lock: &inode->i_sb->s_inode_list_lock); |
503 | list_del_init(entry: &inode->i_sb_list); |
504 | spin_unlock(lock: &inode->i_sb->s_inode_list_lock); |
505 | } |
506 | } |
507 | |
508 | static unsigned long hash(struct super_block *sb, unsigned long hashval) |
509 | { |
510 | unsigned long tmp; |
511 | |
512 | tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / |
513 | L1_CACHE_BYTES; |
514 | tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift); |
515 | return tmp & i_hash_mask; |
516 | } |
517 | |
518 | /** |
519 | * __insert_inode_hash - hash an inode |
520 | * @inode: unhashed inode |
521 | * @hashval: unsigned long value used to locate this object in the |
522 | * inode_hashtable. |
523 | * |
524 | * Add an inode to the inode hash for this superblock. |
525 | */ |
526 | void __insert_inode_hash(struct inode *inode, unsigned long hashval) |
527 | { |
528 | struct hlist_head *b = inode_hashtable + hash(sb: inode->i_sb, hashval); |
529 | |
530 | spin_lock(lock: &inode_hash_lock); |
531 | spin_lock(lock: &inode->i_lock); |
532 | hlist_add_head_rcu(n: &inode->i_hash, h: b); |
533 | spin_unlock(lock: &inode->i_lock); |
534 | spin_unlock(lock: &inode_hash_lock); |
535 | } |
536 | EXPORT_SYMBOL(__insert_inode_hash); |
537 | |
538 | /** |
539 | * __remove_inode_hash - remove an inode from the hash |
540 | * @inode: inode to unhash |
541 | * |
542 | * Remove an inode from the superblock. |
543 | */ |
544 | void __remove_inode_hash(struct inode *inode) |
545 | { |
546 | spin_lock(lock: &inode_hash_lock); |
547 | spin_lock(lock: &inode->i_lock); |
548 | hlist_del_init_rcu(n: &inode->i_hash); |
549 | spin_unlock(lock: &inode->i_lock); |
550 | spin_unlock(lock: &inode_hash_lock); |
551 | } |
552 | EXPORT_SYMBOL(__remove_inode_hash); |
553 | |
554 | void dump_mapping(const struct address_space *mapping) |
555 | { |
556 | struct inode *host; |
557 | const struct address_space_operations *a_ops; |
558 | struct hlist_node *dentry_first; |
559 | struct dentry *dentry_ptr; |
560 | struct dentry dentry; |
561 | unsigned long ino; |
562 | |
563 | /* |
564 | * If mapping is an invalid pointer, we don't want to crash |
565 | * accessing it, so probe everything depending on it carefully. |
566 | */ |
567 | if (get_kernel_nofault(host, &mapping->host) || |
568 | get_kernel_nofault(a_ops, &mapping->a_ops)) { |
569 | pr_warn("invalid mapping:%px\n" , mapping); |
570 | return; |
571 | } |
572 | |
573 | if (!host) { |
574 | pr_warn("aops:%ps\n" , a_ops); |
575 | return; |
576 | } |
577 | |
578 | if (get_kernel_nofault(dentry_first, &host->i_dentry.first) || |
579 | get_kernel_nofault(ino, &host->i_ino)) { |
580 | pr_warn("aops:%ps invalid inode:%px\n" , a_ops, host); |
581 | return; |
582 | } |
583 | |
584 | if (!dentry_first) { |
585 | pr_warn("aops:%ps ino:%lx\n" , a_ops, ino); |
586 | return; |
587 | } |
588 | |
589 | dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); |
590 | if (get_kernel_nofault(dentry, dentry_ptr)) { |
591 | pr_warn("aops:%ps ino:%lx invalid dentry:%px\n" , |
592 | a_ops, ino, dentry_ptr); |
593 | return; |
594 | } |
595 | |
596 | /* |
597 | * if dentry is corrupted, the %pd handler may still crash, |
598 | * but it's unlikely that we reach here with a corrupt mapping |
599 | */ |
600 | pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n" , a_ops, ino, &dentry); |
601 | } |
602 | |
603 | void clear_inode(struct inode *inode) |
604 | { |
605 | /* |
606 | * We have to cycle the i_pages lock here because reclaim can be in the |
607 | * process of removing the last page (in __filemap_remove_folio()) |
608 | * and we must not free the mapping under it. |
609 | */ |
610 | xa_lock_irq(&inode->i_data.i_pages); |
611 | BUG_ON(inode->i_data.nrpages); |
612 | /* |
613 | * Almost always, mapping_empty(&inode->i_data) here; but there are |
614 | * two known and long-standing ways in which nodes may get left behind |
615 | * (when deep radix-tree node allocation failed partway; or when THP |
616 | * collapse_file() failed). Until those two known cases are cleaned up, |
617 | * or a cleanup function is called here, do not BUG_ON(!mapping_empty), |
618 | * nor even WARN_ON(!mapping_empty). |
619 | */ |
620 | xa_unlock_irq(&inode->i_data.i_pages); |
621 | BUG_ON(!list_empty(&inode->i_data.private_list)); |
622 | BUG_ON(!(inode->i_state & I_FREEING)); |
623 | BUG_ON(inode->i_state & I_CLEAR); |
624 | BUG_ON(!list_empty(&inode->i_wb_list)); |
625 | /* don't need i_lock here, no concurrent mods to i_state */ |
626 | inode->i_state = I_FREEING | I_CLEAR; |
627 | } |
628 | EXPORT_SYMBOL(clear_inode); |
629 | |
630 | /* |
631 | * Free the inode passed in, removing it from the lists it is still connected |
632 | * to. We remove any pages still attached to the inode and wait for any IO that |
633 | * is still in progress before finally destroying the inode. |
634 | * |
635 | * An inode must already be marked I_FREEING so that we avoid the inode being |
636 | * moved back onto lists if we race with other code that manipulates the lists |
637 | * (e.g. writeback_single_inode). The caller is responsible for setting this. |
638 | * |
639 | * An inode must already be removed from the LRU list before being evicted from |
640 | * the cache. This should occur atomically with setting the I_FREEING state |
641 | * flag, so no inodes here should ever be on the LRU when being evicted. |
642 | */ |
643 | static void evict(struct inode *inode) |
644 | { |
645 | const struct super_operations *op = inode->i_sb->s_op; |
646 | |
647 | BUG_ON(!(inode->i_state & I_FREEING)); |
648 | BUG_ON(!list_empty(&inode->i_lru)); |
649 | |
650 | if (!list_empty(head: &inode->i_io_list)) |
651 | inode_io_list_del(inode); |
652 | |
653 | inode_sb_list_del(inode); |
654 | |
655 | /* |
656 | * Wait for flusher thread to be done with the inode so that filesystem |
657 | * does not start destroying it while writeback is still running. Since |
658 | * the inode has I_FREEING set, flusher thread won't start new work on |
659 | * the inode. We just have to wait for running writeback to finish. |
660 | */ |
661 | inode_wait_for_writeback(inode); |
662 | |
663 | if (op->evict_inode) { |
664 | op->evict_inode(inode); |
665 | } else { |
666 | truncate_inode_pages_final(&inode->i_data); |
667 | clear_inode(inode); |
668 | } |
669 | if (S_ISCHR(inode->i_mode) && inode->i_cdev) |
670 | cd_forget(inode); |
671 | |
672 | remove_inode_hash(inode); |
673 | |
674 | spin_lock(lock: &inode->i_lock); |
675 | wake_up_bit(word: &inode->i_state, __I_NEW); |
676 | BUG_ON(inode->i_state != (I_FREEING | I_CLEAR)); |
677 | spin_unlock(lock: &inode->i_lock); |
678 | |
679 | destroy_inode(inode); |
680 | } |
681 | |
682 | /* |
683 | * dispose_list - dispose of the contents of a local list |
684 | * @head: the head of the list to free |
685 | * |
686 | * Dispose-list gets a local list with local inodes in it, so it doesn't |
687 | * need to worry about list corruption and SMP locks. |
688 | */ |
689 | static void dispose_list(struct list_head *head) |
690 | { |
691 | while (!list_empty(head)) { |
692 | struct inode *inode; |
693 | |
694 | inode = list_first_entry(head, struct inode, i_lru); |
695 | list_del_init(entry: &inode->i_lru); |
696 | |
697 | evict(inode); |
698 | cond_resched(); |
699 | } |
700 | } |
701 | |
702 | /** |
703 | * evict_inodes - evict all evictable inodes for a superblock |
704 | * @sb: superblock to operate on |
705 | * |
706 | * Make sure that no inodes with zero refcount are retained. This is |
707 | * called by superblock shutdown after having SB_ACTIVE flag removed, |
708 | * so any inode reaching zero refcount during or after that call will |
709 | * be immediately evicted. |
710 | */ |
711 | void evict_inodes(struct super_block *sb) |
712 | { |
713 | struct inode *inode, *next; |
714 | LIST_HEAD(dispose); |
715 | |
716 | again: |
717 | spin_lock(lock: &sb->s_inode_list_lock); |
718 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
719 | if (atomic_read(v: &inode->i_count)) |
720 | continue; |
721 | |
722 | spin_lock(lock: &inode->i_lock); |
723 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
724 | spin_unlock(lock: &inode->i_lock); |
725 | continue; |
726 | } |
727 | |
728 | inode->i_state |= I_FREEING; |
729 | inode_lru_list_del(inode); |
730 | spin_unlock(lock: &inode->i_lock); |
731 | list_add(new: &inode->i_lru, head: &dispose); |
732 | |
733 | /* |
734 | * We can have a ton of inodes to evict at unmount time given |
735 | * enough memory, check to see if we need to go to sleep for a |
736 | * bit so we don't livelock. |
737 | */ |
738 | if (need_resched()) { |
739 | spin_unlock(lock: &sb->s_inode_list_lock); |
740 | cond_resched(); |
741 | dispose_list(head: &dispose); |
742 | goto again; |
743 | } |
744 | } |
745 | spin_unlock(lock: &sb->s_inode_list_lock); |
746 | |
747 | dispose_list(head: &dispose); |
748 | } |
749 | EXPORT_SYMBOL_GPL(evict_inodes); |
750 | |
751 | /** |
752 | * invalidate_inodes - attempt to free all inodes on a superblock |
753 | * @sb: superblock to operate on |
754 | * |
755 | * Attempts to free all inodes (including dirty inodes) for a given superblock. |
756 | */ |
757 | void invalidate_inodes(struct super_block *sb) |
758 | { |
759 | struct inode *inode, *next; |
760 | LIST_HEAD(dispose); |
761 | |
762 | again: |
763 | spin_lock(lock: &sb->s_inode_list_lock); |
764 | list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) { |
765 | spin_lock(lock: &inode->i_lock); |
766 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
767 | spin_unlock(lock: &inode->i_lock); |
768 | continue; |
769 | } |
770 | if (atomic_read(v: &inode->i_count)) { |
771 | spin_unlock(lock: &inode->i_lock); |
772 | continue; |
773 | } |
774 | |
775 | inode->i_state |= I_FREEING; |
776 | inode_lru_list_del(inode); |
777 | spin_unlock(lock: &inode->i_lock); |
778 | list_add(new: &inode->i_lru, head: &dispose); |
779 | if (need_resched()) { |
780 | spin_unlock(lock: &sb->s_inode_list_lock); |
781 | cond_resched(); |
782 | dispose_list(head: &dispose); |
783 | goto again; |
784 | } |
785 | } |
786 | spin_unlock(lock: &sb->s_inode_list_lock); |
787 | |
788 | dispose_list(head: &dispose); |
789 | } |
790 | |
791 | /* |
792 | * Isolate the inode from the LRU in preparation for freeing it. |
793 | * |
794 | * If the inode has the I_REFERENCED flag set, then it means that it has been |
795 | * used recently - the flag is set in iput_final(). When we encounter such an |
796 | * inode, clear the flag and move it to the back of the LRU so it gets another |
797 | * pass through the LRU before it gets reclaimed. This is necessary because of |
798 | * the fact we are doing lazy LRU updates to minimise lock contention so the |
799 | * LRU does not have strict ordering. Hence we don't want to reclaim inodes |
800 | * with this flag set because they are the inodes that are out of order. |
801 | */ |
802 | static enum lru_status inode_lru_isolate(struct list_head *item, |
803 | struct list_lru_one *lru, spinlock_t *lru_lock, void *arg) |
804 | { |
805 | struct list_head *freeable = arg; |
806 | struct inode *inode = container_of(item, struct inode, i_lru); |
807 | |
808 | /* |
809 | * We are inverting the lru lock/inode->i_lock here, so use a |
810 | * trylock. If we fail to get the lock, just skip it. |
811 | */ |
812 | if (!spin_trylock(lock: &inode->i_lock)) |
813 | return LRU_SKIP; |
814 | |
815 | /* |
816 | * Inodes can get referenced, redirtied, or repopulated while |
817 | * they're already on the LRU, and this can make them |
818 | * unreclaimable for a while. Remove them lazily here; iput, |
819 | * sync, or the last page cache deletion will requeue them. |
820 | */ |
821 | if (atomic_read(v: &inode->i_count) || |
822 | (inode->i_state & ~I_REFERENCED) || |
823 | !mapping_shrinkable(mapping: &inode->i_data)) { |
824 | list_lru_isolate(list: lru, item: &inode->i_lru); |
825 | spin_unlock(lock: &inode->i_lock); |
826 | this_cpu_dec(nr_unused); |
827 | return LRU_REMOVED; |
828 | } |
829 | |
830 | /* Recently referenced inodes get one more pass */ |
831 | if (inode->i_state & I_REFERENCED) { |
832 | inode->i_state &= ~I_REFERENCED; |
833 | spin_unlock(lock: &inode->i_lock); |
834 | return LRU_ROTATE; |
835 | } |
836 | |
837 | /* |
838 | * On highmem systems, mapping_shrinkable() permits dropping |
839 | * page cache in order to free up struct inodes: lowmem might |
840 | * be under pressure before the cache inside the highmem zone. |
841 | */ |
842 | if (inode_has_buffers(inode) || !mapping_empty(mapping: &inode->i_data)) { |
843 | __iget(inode); |
844 | spin_unlock(lock: &inode->i_lock); |
845 | spin_unlock(lock: lru_lock); |
846 | if (remove_inode_buffers(inode)) { |
847 | unsigned long reap; |
848 | reap = invalidate_mapping_pages(mapping: &inode->i_data, start: 0, end: -1); |
849 | if (current_is_kswapd()) |
850 | __count_vm_events(item: KSWAPD_INODESTEAL, delta: reap); |
851 | else |
852 | __count_vm_events(item: PGINODESTEAL, delta: reap); |
853 | mm_account_reclaimed_pages(pages: reap); |
854 | } |
855 | iput(inode); |
856 | spin_lock(lock: lru_lock); |
857 | return LRU_RETRY; |
858 | } |
859 | |
860 | WARN_ON(inode->i_state & I_NEW); |
861 | inode->i_state |= I_FREEING; |
862 | list_lru_isolate_move(list: lru, item: &inode->i_lru, head: freeable); |
863 | spin_unlock(lock: &inode->i_lock); |
864 | |
865 | this_cpu_dec(nr_unused); |
866 | return LRU_REMOVED; |
867 | } |
868 | |
869 | /* |
870 | * Walk the superblock inode LRU for freeable inodes and attempt to free them. |
871 | * This is called from the superblock shrinker function with a number of inodes |
872 | * to trim from the LRU. Inodes to be freed are moved to a temporary list and |
873 | * then are freed outside inode_lock by dispose_list(). |
874 | */ |
875 | long prune_icache_sb(struct super_block *sb, struct shrink_control *sc) |
876 | { |
877 | LIST_HEAD(freeable); |
878 | long freed; |
879 | |
880 | freed = list_lru_shrink_walk(lru: &sb->s_inode_lru, sc, |
881 | isolate: inode_lru_isolate, cb_arg: &freeable); |
882 | dispose_list(head: &freeable); |
883 | return freed; |
884 | } |
885 | |
886 | static void __wait_on_freeing_inode(struct inode *inode); |
887 | /* |
888 | * Called with the inode lock held. |
889 | */ |
890 | static struct inode *find_inode(struct super_block *sb, |
891 | struct hlist_head *head, |
892 | int (*test)(struct inode *, void *), |
893 | void *data) |
894 | { |
895 | struct inode *inode = NULL; |
896 | |
897 | repeat: |
898 | hlist_for_each_entry(inode, head, i_hash) { |
899 | if (inode->i_sb != sb) |
900 | continue; |
901 | if (!test(inode, data)) |
902 | continue; |
903 | spin_lock(lock: &inode->i_lock); |
904 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
905 | __wait_on_freeing_inode(inode); |
906 | goto repeat; |
907 | } |
908 | if (unlikely(inode->i_state & I_CREATING)) { |
909 | spin_unlock(lock: &inode->i_lock); |
910 | return ERR_PTR(error: -ESTALE); |
911 | } |
912 | __iget(inode); |
913 | spin_unlock(lock: &inode->i_lock); |
914 | return inode; |
915 | } |
916 | return NULL; |
917 | } |
918 | |
919 | /* |
920 | * find_inode_fast is the fast path version of find_inode, see the comment at |
921 | * iget_locked for details. |
922 | */ |
923 | static struct inode *find_inode_fast(struct super_block *sb, |
924 | struct hlist_head *head, unsigned long ino) |
925 | { |
926 | struct inode *inode = NULL; |
927 | |
928 | repeat: |
929 | hlist_for_each_entry(inode, head, i_hash) { |
930 | if (inode->i_ino != ino) |
931 | continue; |
932 | if (inode->i_sb != sb) |
933 | continue; |
934 | spin_lock(lock: &inode->i_lock); |
935 | if (inode->i_state & (I_FREEING|I_WILL_FREE)) { |
936 | __wait_on_freeing_inode(inode); |
937 | goto repeat; |
938 | } |
939 | if (unlikely(inode->i_state & I_CREATING)) { |
940 | spin_unlock(lock: &inode->i_lock); |
941 | return ERR_PTR(error: -ESTALE); |
942 | } |
943 | __iget(inode); |
944 | spin_unlock(lock: &inode->i_lock); |
945 | return inode; |
946 | } |
947 | return NULL; |
948 | } |
949 | |
950 | /* |
951 | * Each cpu owns a range of LAST_INO_BATCH numbers. |
952 | * 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations, |
953 | * to renew the exhausted range. |
954 | * |
955 | * This does not significantly increase overflow rate because every CPU can |
956 | * consume at most LAST_INO_BATCH-1 unused inode numbers. So there is |
957 | * NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the |
958 | * 2^32 range, and is a worst-case. Even a 50% wastage would only increase |
959 | * overflow rate by 2x, which does not seem too significant. |
960 | * |
961 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
962 | * error if st_ino won't fit in target struct field. Use 32bit counter |
963 | * here to attempt to avoid that. |
964 | */ |
965 | #define LAST_INO_BATCH 1024 |
966 | static DEFINE_PER_CPU(unsigned int, last_ino); |
967 | |
968 | unsigned int get_next_ino(void) |
969 | { |
970 | unsigned int *p = &get_cpu_var(last_ino); |
971 | unsigned int res = *p; |
972 | |
973 | #ifdef CONFIG_SMP |
974 | if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) { |
975 | static atomic_t shared_last_ino; |
976 | int next = atomic_add_return(LAST_INO_BATCH, v: &shared_last_ino); |
977 | |
978 | res = next - LAST_INO_BATCH; |
979 | } |
980 | #endif |
981 | |
982 | res++; |
983 | /* get_next_ino should not provide a 0 inode number */ |
984 | if (unlikely(!res)) |
985 | res++; |
986 | *p = res; |
987 | put_cpu_var(last_ino); |
988 | return res; |
989 | } |
990 | EXPORT_SYMBOL(get_next_ino); |
991 | |
992 | /** |
993 | * new_inode_pseudo - obtain an inode |
994 | * @sb: superblock |
995 | * |
996 | * Allocates a new inode for given superblock. |
997 | * Inode wont be chained in superblock s_inodes list |
998 | * This means : |
999 | * - fs can't be unmount |
1000 | * - quotas, fsnotify, writeback can't work |
1001 | */ |
1002 | struct inode *new_inode_pseudo(struct super_block *sb) |
1003 | { |
1004 | struct inode *inode = alloc_inode(sb); |
1005 | |
1006 | if (inode) { |
1007 | spin_lock(lock: &inode->i_lock); |
1008 | inode->i_state = 0; |
1009 | spin_unlock(lock: &inode->i_lock); |
1010 | } |
1011 | return inode; |
1012 | } |
1013 | |
1014 | /** |
1015 | * new_inode - obtain an inode |
1016 | * @sb: superblock |
1017 | * |
1018 | * Allocates a new inode for given superblock. The default gfp_mask |
1019 | * for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE. |
1020 | * If HIGHMEM pages are unsuitable or it is known that pages allocated |
1021 | * for the page cache are not reclaimable or migratable, |
1022 | * mapping_set_gfp_mask() must be called with suitable flags on the |
1023 | * newly created inode's mapping |
1024 | * |
1025 | */ |
1026 | struct inode *new_inode(struct super_block *sb) |
1027 | { |
1028 | struct inode *inode; |
1029 | |
1030 | inode = new_inode_pseudo(sb); |
1031 | if (inode) |
1032 | inode_sb_list_add(inode); |
1033 | return inode; |
1034 | } |
1035 | EXPORT_SYMBOL(new_inode); |
1036 | |
1037 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
1038 | void lockdep_annotate_inode_mutex_key(struct inode *inode) |
1039 | { |
1040 | if (S_ISDIR(inode->i_mode)) { |
1041 | struct file_system_type *type = inode->i_sb->s_type; |
1042 | |
1043 | /* Set new key only if filesystem hasn't already changed it */ |
1044 | if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { |
1045 | /* |
1046 | * ensure nobody is actually holding i_mutex |
1047 | */ |
1048 | // mutex_destroy(&inode->i_mutex); |
1049 | init_rwsem(&inode->i_rwsem); |
1050 | lockdep_set_class(&inode->i_rwsem, |
1051 | &type->i_mutex_dir_key); |
1052 | } |
1053 | } |
1054 | } |
1055 | EXPORT_SYMBOL(lockdep_annotate_inode_mutex_key); |
1056 | #endif |
1057 | |
1058 | /** |
1059 | * unlock_new_inode - clear the I_NEW state and wake up any waiters |
1060 | * @inode: new inode to unlock |
1061 | * |
1062 | * Called when the inode is fully initialised to clear the new state of the |
1063 | * inode and wake up anyone waiting for the inode to finish initialisation. |
1064 | */ |
1065 | void unlock_new_inode(struct inode *inode) |
1066 | { |
1067 | lockdep_annotate_inode_mutex_key(inode); |
1068 | spin_lock(lock: &inode->i_lock); |
1069 | WARN_ON(!(inode->i_state & I_NEW)); |
1070 | inode->i_state &= ~I_NEW & ~I_CREATING; |
1071 | smp_mb(); |
1072 | wake_up_bit(word: &inode->i_state, __I_NEW); |
1073 | spin_unlock(lock: &inode->i_lock); |
1074 | } |
1075 | EXPORT_SYMBOL(unlock_new_inode); |
1076 | |
1077 | void discard_new_inode(struct inode *inode) |
1078 | { |
1079 | lockdep_annotate_inode_mutex_key(inode); |
1080 | spin_lock(lock: &inode->i_lock); |
1081 | WARN_ON(!(inode->i_state & I_NEW)); |
1082 | inode->i_state &= ~I_NEW; |
1083 | smp_mb(); |
1084 | wake_up_bit(word: &inode->i_state, __I_NEW); |
1085 | spin_unlock(lock: &inode->i_lock); |
1086 | iput(inode); |
1087 | } |
1088 | EXPORT_SYMBOL(discard_new_inode); |
1089 | |
1090 | /** |
1091 | * lock_two_inodes - lock two inodes (may be regular files but also dirs) |
1092 | * |
1093 | * Lock any non-NULL argument. The caller must make sure that if he is passing |
1094 | * in two directories, one is not ancestor of the other. Zero, one or two |
1095 | * objects may be locked by this function. |
1096 | * |
1097 | * @inode1: first inode to lock |
1098 | * @inode2: second inode to lock |
1099 | * @subclass1: inode lock subclass for the first lock obtained |
1100 | * @subclass2: inode lock subclass for the second lock obtained |
1101 | */ |
1102 | void lock_two_inodes(struct inode *inode1, struct inode *inode2, |
1103 | unsigned subclass1, unsigned subclass2) |
1104 | { |
1105 | if (!inode1 || !inode2) { |
1106 | /* |
1107 | * Make sure @subclass1 will be used for the acquired lock. |
1108 | * This is not strictly necessary (no current caller cares) but |
1109 | * let's keep things consistent. |
1110 | */ |
1111 | if (!inode1) |
1112 | swap(inode1, inode2); |
1113 | goto lock; |
1114 | } |
1115 | |
1116 | /* |
1117 | * If one object is directory and the other is not, we must make sure |
1118 | * to lock directory first as the other object may be its child. |
1119 | */ |
1120 | if (S_ISDIR(inode2->i_mode) == S_ISDIR(inode1->i_mode)) { |
1121 | if (inode1 > inode2) |
1122 | swap(inode1, inode2); |
1123 | } else if (!S_ISDIR(inode1->i_mode)) |
1124 | swap(inode1, inode2); |
1125 | lock: |
1126 | if (inode1) |
1127 | inode_lock_nested(inode: inode1, subclass: subclass1); |
1128 | if (inode2 && inode2 != inode1) |
1129 | inode_lock_nested(inode: inode2, subclass: subclass2); |
1130 | } |
1131 | |
1132 | /** |
1133 | * lock_two_nondirectories - take two i_mutexes on non-directory objects |
1134 | * |
1135 | * Lock any non-NULL argument. Passed objects must not be directories. |
1136 | * Zero, one or two objects may be locked by this function. |
1137 | * |
1138 | * @inode1: first inode to lock |
1139 | * @inode2: second inode to lock |
1140 | */ |
1141 | void lock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
1142 | { |
1143 | if (inode1) |
1144 | WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); |
1145 | if (inode2) |
1146 | WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); |
1147 | lock_two_inodes(inode1, inode2, subclass1: I_MUTEX_NORMAL, subclass2: I_MUTEX_NONDIR2); |
1148 | } |
1149 | EXPORT_SYMBOL(lock_two_nondirectories); |
1150 | |
1151 | /** |
1152 | * unlock_two_nondirectories - release locks from lock_two_nondirectories() |
1153 | * @inode1: first inode to unlock |
1154 | * @inode2: second inode to unlock |
1155 | */ |
1156 | void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2) |
1157 | { |
1158 | if (inode1) { |
1159 | WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); |
1160 | inode_unlock(inode: inode1); |
1161 | } |
1162 | if (inode2 && inode2 != inode1) { |
1163 | WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); |
1164 | inode_unlock(inode: inode2); |
1165 | } |
1166 | } |
1167 | EXPORT_SYMBOL(unlock_two_nondirectories); |
1168 | |
1169 | /** |
1170 | * inode_insert5 - obtain an inode from a mounted file system |
1171 | * @inode: pre-allocated inode to use for insert to cache |
1172 | * @hashval: hash value (usually inode number) to get |
1173 | * @test: callback used for comparisons between inodes |
1174 | * @set: callback used to initialize a new struct inode |
1175 | * @data: opaque data pointer to pass to @test and @set |
1176 | * |
1177 | * Search for the inode specified by @hashval and @data in the inode cache, |
1178 | * and if present it is return it with an increased reference count. This is |
1179 | * a variant of iget5_locked() for callers that don't want to fail on memory |
1180 | * allocation of inode. |
1181 | * |
1182 | * If the inode is not in cache, insert the pre-allocated inode to cache and |
1183 | * return it locked, hashed, and with the I_NEW flag set. The file system gets |
1184 | * to fill it in before unlocking it via unlock_new_inode(). |
1185 | * |
1186 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
1187 | * sleep. |
1188 | */ |
1189 | struct inode *inode_insert5(struct inode *inode, unsigned long hashval, |
1190 | int (*test)(struct inode *, void *), |
1191 | int (*set)(struct inode *, void *), void *data) |
1192 | { |
1193 | struct hlist_head *head = inode_hashtable + hash(sb: inode->i_sb, hashval); |
1194 | struct inode *old; |
1195 | |
1196 | again: |
1197 | spin_lock(lock: &inode_hash_lock); |
1198 | old = find_inode(sb: inode->i_sb, head, test, data); |
1199 | if (unlikely(old)) { |
1200 | /* |
1201 | * Uhhuh, somebody else created the same inode under us. |
1202 | * Use the old inode instead of the preallocated one. |
1203 | */ |
1204 | spin_unlock(lock: &inode_hash_lock); |
1205 | if (IS_ERR(ptr: old)) |
1206 | return NULL; |
1207 | wait_on_inode(inode: old); |
1208 | if (unlikely(inode_unhashed(old))) { |
1209 | iput(old); |
1210 | goto again; |
1211 | } |
1212 | return old; |
1213 | } |
1214 | |
1215 | if (set && unlikely(set(inode, data))) { |
1216 | inode = NULL; |
1217 | goto unlock; |
1218 | } |
1219 | |
1220 | /* |
1221 | * Return the locked inode with I_NEW set, the |
1222 | * caller is responsible for filling in the contents |
1223 | */ |
1224 | spin_lock(lock: &inode->i_lock); |
1225 | inode->i_state |= I_NEW; |
1226 | hlist_add_head_rcu(n: &inode->i_hash, h: head); |
1227 | spin_unlock(lock: &inode->i_lock); |
1228 | |
1229 | /* |
1230 | * Add inode to the sb list if it's not already. It has I_NEW at this |
1231 | * point, so it should be safe to test i_sb_list locklessly. |
1232 | */ |
1233 | if (list_empty(head: &inode->i_sb_list)) |
1234 | inode_sb_list_add(inode); |
1235 | unlock: |
1236 | spin_unlock(lock: &inode_hash_lock); |
1237 | |
1238 | return inode; |
1239 | } |
1240 | EXPORT_SYMBOL(inode_insert5); |
1241 | |
1242 | /** |
1243 | * iget5_locked - obtain an inode from a mounted file system |
1244 | * @sb: super block of file system |
1245 | * @hashval: hash value (usually inode number) to get |
1246 | * @test: callback used for comparisons between inodes |
1247 | * @set: callback used to initialize a new struct inode |
1248 | * @data: opaque data pointer to pass to @test and @set |
1249 | * |
1250 | * Search for the inode specified by @hashval and @data in the inode cache, |
1251 | * and if present it is return it with an increased reference count. This is |
1252 | * a generalized version of iget_locked() for file systems where the inode |
1253 | * number is not sufficient for unique identification of an inode. |
1254 | * |
1255 | * If the inode is not in cache, allocate a new inode and return it locked, |
1256 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
1257 | * before unlocking it via unlock_new_inode(). |
1258 | * |
1259 | * Note both @test and @set are called with the inode_hash_lock held, so can't |
1260 | * sleep. |
1261 | */ |
1262 | struct inode *iget5_locked(struct super_block *sb, unsigned long hashval, |
1263 | int (*test)(struct inode *, void *), |
1264 | int (*set)(struct inode *, void *), void *data) |
1265 | { |
1266 | struct inode *inode = ilookup5(sb, hashval, test, data); |
1267 | |
1268 | if (!inode) { |
1269 | struct inode *new = alloc_inode(sb); |
1270 | |
1271 | if (new) { |
1272 | new->i_state = 0; |
1273 | inode = inode_insert5(new, hashval, test, set, data); |
1274 | if (unlikely(inode != new)) |
1275 | destroy_inode(inode: new); |
1276 | } |
1277 | } |
1278 | return inode; |
1279 | } |
1280 | EXPORT_SYMBOL(iget5_locked); |
1281 | |
1282 | /** |
1283 | * iget_locked - obtain an inode from a mounted file system |
1284 | * @sb: super block of file system |
1285 | * @ino: inode number to get |
1286 | * |
1287 | * Search for the inode specified by @ino in the inode cache and if present |
1288 | * return it with an increased reference count. This is for file systems |
1289 | * where the inode number is sufficient for unique identification of an inode. |
1290 | * |
1291 | * If the inode is not in cache, allocate a new inode and return it locked, |
1292 | * hashed, and with the I_NEW flag set. The file system gets to fill it in |
1293 | * before unlocking it via unlock_new_inode(). |
1294 | */ |
1295 | struct inode *iget_locked(struct super_block *sb, unsigned long ino) |
1296 | { |
1297 | struct hlist_head *head = inode_hashtable + hash(sb, hashval: ino); |
1298 | struct inode *inode; |
1299 | again: |
1300 | spin_lock(lock: &inode_hash_lock); |
1301 | inode = find_inode_fast(sb, head, ino); |
1302 | spin_unlock(lock: &inode_hash_lock); |
1303 | if (inode) { |
1304 | if (IS_ERR(ptr: inode)) |
1305 | return NULL; |
1306 | wait_on_inode(inode); |
1307 | if (unlikely(inode_unhashed(inode))) { |
1308 | iput(inode); |
1309 | goto again; |
1310 | } |
1311 | return inode; |
1312 | } |
1313 | |
1314 | inode = alloc_inode(sb); |
1315 | if (inode) { |
1316 | struct inode *old; |
1317 | |
1318 | spin_lock(lock: &inode_hash_lock); |
1319 | /* We released the lock, so.. */ |
1320 | old = find_inode_fast(sb, head, ino); |
1321 | if (!old) { |
1322 | inode->i_ino = ino; |
1323 | spin_lock(lock: &inode->i_lock); |
1324 | inode->i_state = I_NEW; |
1325 | hlist_add_head_rcu(n: &inode->i_hash, h: head); |
1326 | spin_unlock(lock: &inode->i_lock); |
1327 | inode_sb_list_add(inode); |
1328 | spin_unlock(lock: &inode_hash_lock); |
1329 | |
1330 | /* Return the locked inode with I_NEW set, the |
1331 | * caller is responsible for filling in the contents |
1332 | */ |
1333 | return inode; |
1334 | } |
1335 | |
1336 | /* |
1337 | * Uhhuh, somebody else created the same inode under |
1338 | * us. Use the old inode instead of the one we just |
1339 | * allocated. |
1340 | */ |
1341 | spin_unlock(lock: &inode_hash_lock); |
1342 | destroy_inode(inode); |
1343 | if (IS_ERR(ptr: old)) |
1344 | return NULL; |
1345 | inode = old; |
1346 | wait_on_inode(inode); |
1347 | if (unlikely(inode_unhashed(inode))) { |
1348 | iput(inode); |
1349 | goto again; |
1350 | } |
1351 | } |
1352 | return inode; |
1353 | } |
1354 | EXPORT_SYMBOL(iget_locked); |
1355 | |
1356 | /* |
1357 | * search the inode cache for a matching inode number. |
1358 | * If we find one, then the inode number we are trying to |
1359 | * allocate is not unique and so we should not use it. |
1360 | * |
1361 | * Returns 1 if the inode number is unique, 0 if it is not. |
1362 | */ |
1363 | static int test_inode_iunique(struct super_block *sb, unsigned long ino) |
1364 | { |
1365 | struct hlist_head *b = inode_hashtable + hash(sb, hashval: ino); |
1366 | struct inode *inode; |
1367 | |
1368 | hlist_for_each_entry_rcu(inode, b, i_hash) { |
1369 | if (inode->i_ino == ino && inode->i_sb == sb) |
1370 | return 0; |
1371 | } |
1372 | return 1; |
1373 | } |
1374 | |
1375 | /** |
1376 | * iunique - get a unique inode number |
1377 | * @sb: superblock |
1378 | * @max_reserved: highest reserved inode number |
1379 | * |
1380 | * Obtain an inode number that is unique on the system for a given |
1381 | * superblock. This is used by file systems that have no natural |
1382 | * permanent inode numbering system. An inode number is returned that |
1383 | * is higher than the reserved limit but unique. |
1384 | * |
1385 | * BUGS: |
1386 | * With a large number of inodes live on the file system this function |
1387 | * currently becomes quite slow. |
1388 | */ |
1389 | ino_t iunique(struct super_block *sb, ino_t max_reserved) |
1390 | { |
1391 | /* |
1392 | * On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW |
1393 | * error if st_ino won't fit in target struct field. Use 32bit counter |
1394 | * here to attempt to avoid that. |
1395 | */ |
1396 | static DEFINE_SPINLOCK(iunique_lock); |
1397 | static unsigned int counter; |
1398 | ino_t res; |
1399 | |
1400 | rcu_read_lock(); |
1401 | spin_lock(lock: &iunique_lock); |
1402 | do { |
1403 | if (counter <= max_reserved) |
1404 | counter = max_reserved + 1; |
1405 | res = counter++; |
1406 | } while (!test_inode_iunique(sb, ino: res)); |
1407 | spin_unlock(lock: &iunique_lock); |
1408 | rcu_read_unlock(); |
1409 | |
1410 | return res; |
1411 | } |
1412 | EXPORT_SYMBOL(iunique); |
1413 | |
1414 | struct inode *igrab(struct inode *inode) |
1415 | { |
1416 | spin_lock(lock: &inode->i_lock); |
1417 | if (!(inode->i_state & (I_FREEING|I_WILL_FREE))) { |
1418 | __iget(inode); |
1419 | spin_unlock(lock: &inode->i_lock); |
1420 | } else { |
1421 | spin_unlock(lock: &inode->i_lock); |
1422 | /* |
1423 | * Handle the case where s_op->clear_inode is not been |
1424 | * called yet, and somebody is calling igrab |
1425 | * while the inode is getting freed. |
1426 | */ |
1427 | inode = NULL; |
1428 | } |
1429 | return inode; |
1430 | } |
1431 | EXPORT_SYMBOL(igrab); |
1432 | |
1433 | /** |
1434 | * ilookup5_nowait - search for an inode in the inode cache |
1435 | * @sb: super block of file system to search |
1436 | * @hashval: hash value (usually inode number) to search for |
1437 | * @test: callback used for comparisons between inodes |
1438 | * @data: opaque data pointer to pass to @test |
1439 | * |
1440 | * Search for the inode specified by @hashval and @data in the inode cache. |
1441 | * If the inode is in the cache, the inode is returned with an incremented |
1442 | * reference count. |
1443 | * |
1444 | * Note: I_NEW is not waited upon so you have to be very careful what you do |
1445 | * with the returned inode. You probably should be using ilookup5() instead. |
1446 | * |
1447 | * Note2: @test is called with the inode_hash_lock held, so can't sleep. |
1448 | */ |
1449 | struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval, |
1450 | int (*test)(struct inode *, void *), void *data) |
1451 | { |
1452 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1453 | struct inode *inode; |
1454 | |
1455 | spin_lock(lock: &inode_hash_lock); |
1456 | inode = find_inode(sb, head, test, data); |
1457 | spin_unlock(lock: &inode_hash_lock); |
1458 | |
1459 | return IS_ERR(ptr: inode) ? NULL : inode; |
1460 | } |
1461 | EXPORT_SYMBOL(ilookup5_nowait); |
1462 | |
1463 | /** |
1464 | * ilookup5 - search for an inode in the inode cache |
1465 | * @sb: super block of file system to search |
1466 | * @hashval: hash value (usually inode number) to search for |
1467 | * @test: callback used for comparisons between inodes |
1468 | * @data: opaque data pointer to pass to @test |
1469 | * |
1470 | * Search for the inode specified by @hashval and @data in the inode cache, |
1471 | * and if the inode is in the cache, return the inode with an incremented |
1472 | * reference count. Waits on I_NEW before returning the inode. |
1473 | * returned with an incremented reference count. |
1474 | * |
1475 | * This is a generalized version of ilookup() for file systems where the |
1476 | * inode number is not sufficient for unique identification of an inode. |
1477 | * |
1478 | * Note: @test is called with the inode_hash_lock held, so can't sleep. |
1479 | */ |
1480 | struct inode *ilookup5(struct super_block *sb, unsigned long hashval, |
1481 | int (*test)(struct inode *, void *), void *data) |
1482 | { |
1483 | struct inode *inode; |
1484 | again: |
1485 | inode = ilookup5_nowait(sb, hashval, test, data); |
1486 | if (inode) { |
1487 | wait_on_inode(inode); |
1488 | if (unlikely(inode_unhashed(inode))) { |
1489 | iput(inode); |
1490 | goto again; |
1491 | } |
1492 | } |
1493 | return inode; |
1494 | } |
1495 | EXPORT_SYMBOL(ilookup5); |
1496 | |
1497 | /** |
1498 | * ilookup - search for an inode in the inode cache |
1499 | * @sb: super block of file system to search |
1500 | * @ino: inode number to search for |
1501 | * |
1502 | * Search for the inode @ino in the inode cache, and if the inode is in the |
1503 | * cache, the inode is returned with an incremented reference count. |
1504 | */ |
1505 | struct inode *ilookup(struct super_block *sb, unsigned long ino) |
1506 | { |
1507 | struct hlist_head *head = inode_hashtable + hash(sb, hashval: ino); |
1508 | struct inode *inode; |
1509 | again: |
1510 | spin_lock(lock: &inode_hash_lock); |
1511 | inode = find_inode_fast(sb, head, ino); |
1512 | spin_unlock(lock: &inode_hash_lock); |
1513 | |
1514 | if (inode) { |
1515 | if (IS_ERR(ptr: inode)) |
1516 | return NULL; |
1517 | wait_on_inode(inode); |
1518 | if (unlikely(inode_unhashed(inode))) { |
1519 | iput(inode); |
1520 | goto again; |
1521 | } |
1522 | } |
1523 | return inode; |
1524 | } |
1525 | EXPORT_SYMBOL(ilookup); |
1526 | |
1527 | /** |
1528 | * find_inode_nowait - find an inode in the inode cache |
1529 | * @sb: super block of file system to search |
1530 | * @hashval: hash value (usually inode number) to search for |
1531 | * @match: callback used for comparisons between inodes |
1532 | * @data: opaque data pointer to pass to @match |
1533 | * |
1534 | * Search for the inode specified by @hashval and @data in the inode |
1535 | * cache, where the helper function @match will return 0 if the inode |
1536 | * does not match, 1 if the inode does match, and -1 if the search |
1537 | * should be stopped. The @match function must be responsible for |
1538 | * taking the i_lock spin_lock and checking i_state for an inode being |
1539 | * freed or being initialized, and incrementing the reference count |
1540 | * before returning 1. It also must not sleep, since it is called with |
1541 | * the inode_hash_lock spinlock held. |
1542 | * |
1543 | * This is a even more generalized version of ilookup5() when the |
1544 | * function must never block --- find_inode() can block in |
1545 | * __wait_on_freeing_inode() --- or when the caller can not increment |
1546 | * the reference count because the resulting iput() might cause an |
1547 | * inode eviction. The tradeoff is that the @match funtion must be |
1548 | * very carefully implemented. |
1549 | */ |
1550 | struct inode *find_inode_nowait(struct super_block *sb, |
1551 | unsigned long hashval, |
1552 | int (*match)(struct inode *, unsigned long, |
1553 | void *), |
1554 | void *data) |
1555 | { |
1556 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1557 | struct inode *inode, *ret_inode = NULL; |
1558 | int mval; |
1559 | |
1560 | spin_lock(lock: &inode_hash_lock); |
1561 | hlist_for_each_entry(inode, head, i_hash) { |
1562 | if (inode->i_sb != sb) |
1563 | continue; |
1564 | mval = match(inode, hashval, data); |
1565 | if (mval == 0) |
1566 | continue; |
1567 | if (mval == 1) |
1568 | ret_inode = inode; |
1569 | goto out; |
1570 | } |
1571 | out: |
1572 | spin_unlock(lock: &inode_hash_lock); |
1573 | return ret_inode; |
1574 | } |
1575 | EXPORT_SYMBOL(find_inode_nowait); |
1576 | |
1577 | /** |
1578 | * find_inode_rcu - find an inode in the inode cache |
1579 | * @sb: Super block of file system to search |
1580 | * @hashval: Key to hash |
1581 | * @test: Function to test match on an inode |
1582 | * @data: Data for test function |
1583 | * |
1584 | * Search for the inode specified by @hashval and @data in the inode cache, |
1585 | * where the helper function @test will return 0 if the inode does not match |
1586 | * and 1 if it does. The @test function must be responsible for taking the |
1587 | * i_lock spin_lock and checking i_state for an inode being freed or being |
1588 | * initialized. |
1589 | * |
1590 | * If successful, this will return the inode for which the @test function |
1591 | * returned 1 and NULL otherwise. |
1592 | * |
1593 | * The @test function is not permitted to take a ref on any inode presented. |
1594 | * It is also not permitted to sleep. |
1595 | * |
1596 | * The caller must hold the RCU read lock. |
1597 | */ |
1598 | struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval, |
1599 | int (*test)(struct inode *, void *), void *data) |
1600 | { |
1601 | struct hlist_head *head = inode_hashtable + hash(sb, hashval); |
1602 | struct inode *inode; |
1603 | |
1604 | RCU_LOCKDEP_WARN(!rcu_read_lock_held(), |
1605 | "suspicious find_inode_rcu() usage" ); |
1606 | |
1607 | hlist_for_each_entry_rcu(inode, head, i_hash) { |
1608 | if (inode->i_sb == sb && |
1609 | !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE)) && |
1610 | test(inode, data)) |
1611 | return inode; |
1612 | } |
1613 | return NULL; |
1614 | } |
1615 | EXPORT_SYMBOL(find_inode_rcu); |
1616 | |
1617 | /** |
1618 | * find_inode_by_ino_rcu - Find an inode in the inode cache |
1619 | * @sb: Super block of file system to search |
1620 | * @ino: The inode number to match |
1621 | * |
1622 | * Search for the inode specified by @hashval and @data in the inode cache, |
1623 | * where the helper function @test will return 0 if the inode does not match |
1624 | * and 1 if it does. The @test function must be responsible for taking the |
1625 | * i_lock spin_lock and checking i_state for an inode being freed or being |
1626 | * initialized. |
1627 | * |
1628 | * If successful, this will return the inode for which the @test function |
1629 | * returned 1 and NULL otherwise. |
1630 | * |
1631 | * The @test function is not permitted to take a ref on any inode presented. |
1632 | * It is also not permitted to sleep. |
1633 | * |
1634 | * The caller must hold the RCU read lock. |
1635 | */ |
1636 | struct inode *find_inode_by_ino_rcu(struct super_block *sb, |
1637 | unsigned long ino) |
1638 | { |
1639 | struct hlist_head *head = inode_hashtable + hash(sb, hashval: ino); |
1640 | struct inode *inode; |
1641 | |
1642 | RCU_LOCKDEP_WARN(!rcu_read_lock_held(), |
1643 | "suspicious find_inode_by_ino_rcu() usage" ); |
1644 | |
1645 | hlist_for_each_entry_rcu(inode, head, i_hash) { |
1646 | if (inode->i_ino == ino && |
1647 | inode->i_sb == sb && |
1648 | !(READ_ONCE(inode->i_state) & (I_FREEING | I_WILL_FREE))) |
1649 | return inode; |
1650 | } |
1651 | return NULL; |
1652 | } |
1653 | EXPORT_SYMBOL(find_inode_by_ino_rcu); |
1654 | |
1655 | int insert_inode_locked(struct inode *inode) |
1656 | { |
1657 | struct super_block *sb = inode->i_sb; |
1658 | ino_t ino = inode->i_ino; |
1659 | struct hlist_head *head = inode_hashtable + hash(sb, hashval: ino); |
1660 | |
1661 | while (1) { |
1662 | struct inode *old = NULL; |
1663 | spin_lock(lock: &inode_hash_lock); |
1664 | hlist_for_each_entry(old, head, i_hash) { |
1665 | if (old->i_ino != ino) |
1666 | continue; |
1667 | if (old->i_sb != sb) |
1668 | continue; |
1669 | spin_lock(lock: &old->i_lock); |
1670 | if (old->i_state & (I_FREEING|I_WILL_FREE)) { |
1671 | spin_unlock(lock: &old->i_lock); |
1672 | continue; |
1673 | } |
1674 | break; |
1675 | } |
1676 | if (likely(!old)) { |
1677 | spin_lock(lock: &inode->i_lock); |
1678 | inode->i_state |= I_NEW | I_CREATING; |
1679 | hlist_add_head_rcu(n: &inode->i_hash, h: head); |
1680 | spin_unlock(lock: &inode->i_lock); |
1681 | spin_unlock(lock: &inode_hash_lock); |
1682 | return 0; |
1683 | } |
1684 | if (unlikely(old->i_state & I_CREATING)) { |
1685 | spin_unlock(lock: &old->i_lock); |
1686 | spin_unlock(lock: &inode_hash_lock); |
1687 | return -EBUSY; |
1688 | } |
1689 | __iget(inode: old); |
1690 | spin_unlock(lock: &old->i_lock); |
1691 | spin_unlock(lock: &inode_hash_lock); |
1692 | wait_on_inode(inode: old); |
1693 | if (unlikely(!inode_unhashed(old))) { |
1694 | iput(old); |
1695 | return -EBUSY; |
1696 | } |
1697 | iput(old); |
1698 | } |
1699 | } |
1700 | EXPORT_SYMBOL(insert_inode_locked); |
1701 | |
1702 | int insert_inode_locked4(struct inode *inode, unsigned long hashval, |
1703 | int (*test)(struct inode *, void *), void *data) |
1704 | { |
1705 | struct inode *old; |
1706 | |
1707 | inode->i_state |= I_CREATING; |
1708 | old = inode_insert5(inode, hashval, test, NULL, data); |
1709 | |
1710 | if (old != inode) { |
1711 | iput(old); |
1712 | return -EBUSY; |
1713 | } |
1714 | return 0; |
1715 | } |
1716 | EXPORT_SYMBOL(insert_inode_locked4); |
1717 | |
1718 | |
1719 | int generic_delete_inode(struct inode *inode) |
1720 | { |
1721 | return 1; |
1722 | } |
1723 | EXPORT_SYMBOL(generic_delete_inode); |
1724 | |
1725 | /* |
1726 | * Called when we're dropping the last reference |
1727 | * to an inode. |
1728 | * |
1729 | * Call the FS "drop_inode()" function, defaulting to |
1730 | * the legacy UNIX filesystem behaviour. If it tells |
1731 | * us to evict inode, do so. Otherwise, retain inode |
1732 | * in cache if fs is alive, sync and evict if fs is |
1733 | * shutting down. |
1734 | */ |
1735 | static void iput_final(struct inode *inode) |
1736 | { |
1737 | struct super_block *sb = inode->i_sb; |
1738 | const struct super_operations *op = inode->i_sb->s_op; |
1739 | unsigned long state; |
1740 | int drop; |
1741 | |
1742 | WARN_ON(inode->i_state & I_NEW); |
1743 | |
1744 | if (op->drop_inode) |
1745 | drop = op->drop_inode(inode); |
1746 | else |
1747 | drop = generic_drop_inode(inode); |
1748 | |
1749 | if (!drop && |
1750 | !(inode->i_state & I_DONTCACHE) && |
1751 | (sb->s_flags & SB_ACTIVE)) { |
1752 | __inode_add_lru(inode, rotate: true); |
1753 | spin_unlock(lock: &inode->i_lock); |
1754 | return; |
1755 | } |
1756 | |
1757 | state = inode->i_state; |
1758 | if (!drop) { |
1759 | WRITE_ONCE(inode->i_state, state | I_WILL_FREE); |
1760 | spin_unlock(lock: &inode->i_lock); |
1761 | |
1762 | write_inode_now(inode, sync: 1); |
1763 | |
1764 | spin_lock(lock: &inode->i_lock); |
1765 | state = inode->i_state; |
1766 | WARN_ON(state & I_NEW); |
1767 | state &= ~I_WILL_FREE; |
1768 | } |
1769 | |
1770 | WRITE_ONCE(inode->i_state, state | I_FREEING); |
1771 | if (!list_empty(head: &inode->i_lru)) |
1772 | inode_lru_list_del(inode); |
1773 | spin_unlock(lock: &inode->i_lock); |
1774 | |
1775 | evict(inode); |
1776 | } |
1777 | |
1778 | /** |
1779 | * iput - put an inode |
1780 | * @inode: inode to put |
1781 | * |
1782 | * Puts an inode, dropping its usage count. If the inode use count hits |
1783 | * zero, the inode is then freed and may also be destroyed. |
1784 | * |
1785 | * Consequently, iput() can sleep. |
1786 | */ |
1787 | void iput(struct inode *inode) |
1788 | { |
1789 | if (!inode) |
1790 | return; |
1791 | BUG_ON(inode->i_state & I_CLEAR); |
1792 | retry: |
1793 | if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) { |
1794 | if (inode->i_nlink && (inode->i_state & I_DIRTY_TIME)) { |
1795 | atomic_inc(v: &inode->i_count); |
1796 | spin_unlock(lock: &inode->i_lock); |
1797 | trace_writeback_lazytime_iput(inode); |
1798 | mark_inode_dirty_sync(inode); |
1799 | goto retry; |
1800 | } |
1801 | iput_final(inode); |
1802 | } |
1803 | } |
1804 | EXPORT_SYMBOL(iput); |
1805 | |
1806 | #ifdef CONFIG_BLOCK |
1807 | /** |
1808 | * bmap - find a block number in a file |
1809 | * @inode: inode owning the block number being requested |
1810 | * @block: pointer containing the block to find |
1811 | * |
1812 | * Replaces the value in ``*block`` with the block number on the device holding |
1813 | * corresponding to the requested block number in the file. |
1814 | * That is, asked for block 4 of inode 1 the function will replace the |
1815 | * 4 in ``*block``, with disk block relative to the disk start that holds that |
1816 | * block of the file. |
1817 | * |
1818 | * Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a |
1819 | * hole, returns 0 and ``*block`` is also set to 0. |
1820 | */ |
1821 | int bmap(struct inode *inode, sector_t *block) |
1822 | { |
1823 | if (!inode->i_mapping->a_ops->bmap) |
1824 | return -EINVAL; |
1825 | |
1826 | *block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block); |
1827 | return 0; |
1828 | } |
1829 | EXPORT_SYMBOL(bmap); |
1830 | #endif |
1831 | |
1832 | /* |
1833 | * With relative atime, only update atime if the previous atime is |
1834 | * earlier than or equal to either the ctime or mtime, |
1835 | * or if at least a day has passed since the last atime update. |
1836 | */ |
1837 | static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, |
1838 | struct timespec64 now) |
1839 | { |
1840 | struct timespec64 atime, mtime, ctime; |
1841 | |
1842 | if (!(mnt->mnt_flags & MNT_RELATIME)) |
1843 | return 1; |
1844 | /* |
1845 | * Is mtime younger than or equal to atime? If yes, update atime: |
1846 | */ |
1847 | atime = inode_get_atime(inode); |
1848 | mtime = inode_get_mtime(inode); |
1849 | if (timespec64_compare(lhs: &mtime, rhs: &atime) >= 0) |
1850 | return 1; |
1851 | /* |
1852 | * Is ctime younger than or equal to atime? If yes, update atime: |
1853 | */ |
1854 | ctime = inode_get_ctime(inode); |
1855 | if (timespec64_compare(lhs: &ctime, rhs: &atime) >= 0) |
1856 | return 1; |
1857 | |
1858 | /* |
1859 | * Is the previous atime value older than a day? If yes, |
1860 | * update atime: |
1861 | */ |
1862 | if ((long)(now.tv_sec - atime.tv_sec) >= 24*60*60) |
1863 | return 1; |
1864 | /* |
1865 | * Good, we can skip the atime update: |
1866 | */ |
1867 | return 0; |
1868 | } |
1869 | |
1870 | /** |
1871 | * inode_update_timestamps - update the timestamps on the inode |
1872 | * @inode: inode to be updated |
1873 | * @flags: S_* flags that needed to be updated |
1874 | * |
1875 | * The update_time function is called when an inode's timestamps need to be |
1876 | * updated for a read or write operation. This function handles updating the |
1877 | * actual timestamps. It's up to the caller to ensure that the inode is marked |
1878 | * dirty appropriately. |
1879 | * |
1880 | * In the case where any of S_MTIME, S_CTIME, or S_VERSION need to be updated, |
1881 | * attempt to update all three of them. S_ATIME updates can be handled |
1882 | * independently of the rest. |
1883 | * |
1884 | * Returns a set of S_* flags indicating which values changed. |
1885 | */ |
1886 | int inode_update_timestamps(struct inode *inode, int flags) |
1887 | { |
1888 | int updated = 0; |
1889 | struct timespec64 now; |
1890 | |
1891 | if (flags & (S_MTIME|S_CTIME|S_VERSION)) { |
1892 | struct timespec64 ctime = inode_get_ctime(inode); |
1893 | struct timespec64 mtime = inode_get_mtime(inode); |
1894 | |
1895 | now = inode_set_ctime_current(inode); |
1896 | if (!timespec64_equal(a: &now, b: &ctime)) |
1897 | updated |= S_CTIME; |
1898 | if (!timespec64_equal(a: &now, b: &mtime)) { |
1899 | inode_set_mtime_to_ts(inode, ts: now); |
1900 | updated |= S_MTIME; |
1901 | } |
1902 | if (IS_I_VERSION(inode) && inode_maybe_inc_iversion(inode, force: updated)) |
1903 | updated |= S_VERSION; |
1904 | } else { |
1905 | now = current_time(inode); |
1906 | } |
1907 | |
1908 | if (flags & S_ATIME) { |
1909 | struct timespec64 atime = inode_get_atime(inode); |
1910 | |
1911 | if (!timespec64_equal(a: &now, b: &atime)) { |
1912 | inode_set_atime_to_ts(inode, ts: now); |
1913 | updated |= S_ATIME; |
1914 | } |
1915 | } |
1916 | return updated; |
1917 | } |
1918 | EXPORT_SYMBOL(inode_update_timestamps); |
1919 | |
1920 | /** |
1921 | * generic_update_time - update the timestamps on the inode |
1922 | * @inode: inode to be updated |
1923 | * @flags: S_* flags that needed to be updated |
1924 | * |
1925 | * The update_time function is called when an inode's timestamps need to be |
1926 | * updated for a read or write operation. In the case where any of S_MTIME, S_CTIME, |
1927 | * or S_VERSION need to be updated we attempt to update all three of them. S_ATIME |
1928 | * updates can be handled done independently of the rest. |
1929 | * |
1930 | * Returns a S_* mask indicating which fields were updated. |
1931 | */ |
1932 | int generic_update_time(struct inode *inode, int flags) |
1933 | { |
1934 | int updated = inode_update_timestamps(inode, flags); |
1935 | int dirty_flags = 0; |
1936 | |
1937 | if (updated & (S_ATIME|S_MTIME|S_CTIME)) |
1938 | dirty_flags = inode->i_sb->s_flags & SB_LAZYTIME ? I_DIRTY_TIME : I_DIRTY_SYNC; |
1939 | if (updated & S_VERSION) |
1940 | dirty_flags |= I_DIRTY_SYNC; |
1941 | __mark_inode_dirty(inode, dirty_flags); |
1942 | return updated; |
1943 | } |
1944 | EXPORT_SYMBOL(generic_update_time); |
1945 | |
1946 | /* |
1947 | * This does the actual work of updating an inodes time or version. Must have |
1948 | * had called mnt_want_write() before calling this. |
1949 | */ |
1950 | int inode_update_time(struct inode *inode, int flags) |
1951 | { |
1952 | if (inode->i_op->update_time) |
1953 | return inode->i_op->update_time(inode, flags); |
1954 | generic_update_time(inode, flags); |
1955 | return 0; |
1956 | } |
1957 | EXPORT_SYMBOL(inode_update_time); |
1958 | |
1959 | /** |
1960 | * atime_needs_update - update the access time |
1961 | * @path: the &struct path to update |
1962 | * @inode: inode to update |
1963 | * |
1964 | * Update the accessed time on an inode and mark it for writeback. |
1965 | * This function automatically handles read only file systems and media, |
1966 | * as well as the "noatime" flag and inode specific "noatime" markers. |
1967 | */ |
1968 | bool atime_needs_update(const struct path *path, struct inode *inode) |
1969 | { |
1970 | struct vfsmount *mnt = path->mnt; |
1971 | struct timespec64 now, atime; |
1972 | |
1973 | if (inode->i_flags & S_NOATIME) |
1974 | return false; |
1975 | |
1976 | /* Atime updates will likely cause i_uid and i_gid to be written |
1977 | * back improprely if their true value is unknown to the vfs. |
1978 | */ |
1979 | if (HAS_UNMAPPED_ID(idmap: mnt_idmap(mnt), inode)) |
1980 | return false; |
1981 | |
1982 | if (IS_NOATIME(inode)) |
1983 | return false; |
1984 | if ((inode->i_sb->s_flags & SB_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1985 | return false; |
1986 | |
1987 | if (mnt->mnt_flags & MNT_NOATIME) |
1988 | return false; |
1989 | if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)) |
1990 | return false; |
1991 | |
1992 | now = current_time(inode); |
1993 | |
1994 | if (!relatime_need_update(mnt, inode, now)) |
1995 | return false; |
1996 | |
1997 | atime = inode_get_atime(inode); |
1998 | if (timespec64_equal(a: &atime, b: &now)) |
1999 | return false; |
2000 | |
2001 | return true; |
2002 | } |
2003 | |
2004 | void touch_atime(const struct path *path) |
2005 | { |
2006 | struct vfsmount *mnt = path->mnt; |
2007 | struct inode *inode = d_inode(dentry: path->dentry); |
2008 | |
2009 | if (!atime_needs_update(path, inode)) |
2010 | return; |
2011 | |
2012 | if (!sb_start_write_trylock(sb: inode->i_sb)) |
2013 | return; |
2014 | |
2015 | if (mnt_get_write_access(mnt) != 0) |
2016 | goto skip_update; |
2017 | /* |
2018 | * File systems can error out when updating inodes if they need to |
2019 | * allocate new space to modify an inode (such is the case for |
2020 | * Btrfs), but since we touch atime while walking down the path we |
2021 | * really don't care if we failed to update the atime of the file, |
2022 | * so just ignore the return value. |
2023 | * We may also fail on filesystems that have the ability to make parts |
2024 | * of the fs read only, e.g. subvolumes in Btrfs. |
2025 | */ |
2026 | inode_update_time(inode, S_ATIME); |
2027 | mnt_put_write_access(mnt); |
2028 | skip_update: |
2029 | sb_end_write(sb: inode->i_sb); |
2030 | } |
2031 | EXPORT_SYMBOL(touch_atime); |
2032 | |
2033 | /* |
2034 | * Return mask of changes for notify_change() that need to be done as a |
2035 | * response to write or truncate. Return 0 if nothing has to be changed. |
2036 | * Negative value on error (change should be denied). |
2037 | */ |
2038 | int dentry_needs_remove_privs(struct mnt_idmap *idmap, |
2039 | struct dentry *dentry) |
2040 | { |
2041 | struct inode *inode = d_inode(dentry); |
2042 | int mask = 0; |
2043 | int ret; |
2044 | |
2045 | if (IS_NOSEC(inode)) |
2046 | return 0; |
2047 | |
2048 | mask = setattr_should_drop_suidgid(idmap, inode); |
2049 | ret = security_inode_need_killpriv(dentry); |
2050 | if (ret < 0) |
2051 | return ret; |
2052 | if (ret) |
2053 | mask |= ATTR_KILL_PRIV; |
2054 | return mask; |
2055 | } |
2056 | |
2057 | static int __remove_privs(struct mnt_idmap *idmap, |
2058 | struct dentry *dentry, int kill) |
2059 | { |
2060 | struct iattr newattrs; |
2061 | |
2062 | newattrs.ia_valid = ATTR_FORCE | kill; |
2063 | /* |
2064 | * Note we call this on write, so notify_change will not |
2065 | * encounter any conflicting delegations: |
2066 | */ |
2067 | return notify_change(idmap, dentry, &newattrs, NULL); |
2068 | } |
2069 | |
2070 | static int __file_remove_privs(struct file *file, unsigned int flags) |
2071 | { |
2072 | struct dentry *dentry = file_dentry(file); |
2073 | struct inode *inode = file_inode(f: file); |
2074 | int error = 0; |
2075 | int kill; |
2076 | |
2077 | if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) |
2078 | return 0; |
2079 | |
2080 | kill = dentry_needs_remove_privs(idmap: file_mnt_idmap(file), dentry); |
2081 | if (kill < 0) |
2082 | return kill; |
2083 | |
2084 | if (kill) { |
2085 | if (flags & IOCB_NOWAIT) |
2086 | return -EAGAIN; |
2087 | |
2088 | error = __remove_privs(idmap: file_mnt_idmap(file), dentry, kill); |
2089 | } |
2090 | |
2091 | if (!error) |
2092 | inode_has_no_xattr(inode); |
2093 | return error; |
2094 | } |
2095 | |
2096 | /** |
2097 | * file_remove_privs - remove special file privileges (suid, capabilities) |
2098 | * @file: file to remove privileges from |
2099 | * |
2100 | * When file is modified by a write or truncation ensure that special |
2101 | * file privileges are removed. |
2102 | * |
2103 | * Return: 0 on success, negative errno on failure. |
2104 | */ |
2105 | int file_remove_privs(struct file *file) |
2106 | { |
2107 | return __file_remove_privs(file, flags: 0); |
2108 | } |
2109 | EXPORT_SYMBOL(file_remove_privs); |
2110 | |
2111 | static int inode_needs_update_time(struct inode *inode) |
2112 | { |
2113 | int sync_it = 0; |
2114 | struct timespec64 now = current_time(inode); |
2115 | struct timespec64 ts; |
2116 | |
2117 | /* First try to exhaust all avenues to not sync */ |
2118 | if (IS_NOCMTIME(inode)) |
2119 | return 0; |
2120 | |
2121 | ts = inode_get_mtime(inode); |
2122 | if (!timespec64_equal(a: &ts, b: &now)) |
2123 | sync_it = S_MTIME; |
2124 | |
2125 | ts = inode_get_ctime(inode); |
2126 | if (!timespec64_equal(a: &ts, b: &now)) |
2127 | sync_it |= S_CTIME; |
2128 | |
2129 | if (IS_I_VERSION(inode) && inode_iversion_need_inc(inode)) |
2130 | sync_it |= S_VERSION; |
2131 | |
2132 | return sync_it; |
2133 | } |
2134 | |
2135 | static int __file_update_time(struct file *file, int sync_mode) |
2136 | { |
2137 | int ret = 0; |
2138 | struct inode *inode = file_inode(f: file); |
2139 | |
2140 | /* try to update time settings */ |
2141 | if (!mnt_get_write_access_file(file)) { |
2142 | ret = inode_update_time(inode, sync_mode); |
2143 | mnt_put_write_access_file(file); |
2144 | } |
2145 | |
2146 | return ret; |
2147 | } |
2148 | |
2149 | /** |
2150 | * file_update_time - update mtime and ctime time |
2151 | * @file: file accessed |
2152 | * |
2153 | * Update the mtime and ctime members of an inode and mark the inode for |
2154 | * writeback. Note that this function is meant exclusively for usage in |
2155 | * the file write path of filesystems, and filesystems may choose to |
2156 | * explicitly ignore updates via this function with the _NOCMTIME inode |
2157 | * flag, e.g. for network filesystem where these imestamps are handled |
2158 | * by the server. This can return an error for file systems who need to |
2159 | * allocate space in order to update an inode. |
2160 | * |
2161 | * Return: 0 on success, negative errno on failure. |
2162 | */ |
2163 | int file_update_time(struct file *file) |
2164 | { |
2165 | int ret; |
2166 | struct inode *inode = file_inode(f: file); |
2167 | |
2168 | ret = inode_needs_update_time(inode); |
2169 | if (ret <= 0) |
2170 | return ret; |
2171 | |
2172 | return __file_update_time(file, sync_mode: ret); |
2173 | } |
2174 | EXPORT_SYMBOL(file_update_time); |
2175 | |
2176 | /** |
2177 | * file_modified_flags - handle mandated vfs changes when modifying a file |
2178 | * @file: file that was modified |
2179 | * @flags: kiocb flags |
2180 | * |
2181 | * When file has been modified ensure that special |
2182 | * file privileges are removed and time settings are updated. |
2183 | * |
2184 | * If IOCB_NOWAIT is set, special file privileges will not be removed and |
2185 | * time settings will not be updated. It will return -EAGAIN. |
2186 | * |
2187 | * Context: Caller must hold the file's inode lock. |
2188 | * |
2189 | * Return: 0 on success, negative errno on failure. |
2190 | */ |
2191 | static int file_modified_flags(struct file *file, int flags) |
2192 | { |
2193 | int ret; |
2194 | struct inode *inode = file_inode(f: file); |
2195 | |
2196 | /* |
2197 | * Clear the security bits if the process is not being run by root. |
2198 | * This keeps people from modifying setuid and setgid binaries. |
2199 | */ |
2200 | ret = __file_remove_privs(file, flags); |
2201 | if (ret) |
2202 | return ret; |
2203 | |
2204 | if (unlikely(file->f_mode & FMODE_NOCMTIME)) |
2205 | return 0; |
2206 | |
2207 | ret = inode_needs_update_time(inode); |
2208 | if (ret <= 0) |
2209 | return ret; |
2210 | if (flags & IOCB_NOWAIT) |
2211 | return -EAGAIN; |
2212 | |
2213 | return __file_update_time(file, sync_mode: ret); |
2214 | } |
2215 | |
2216 | /** |
2217 | * file_modified - handle mandated vfs changes when modifying a file |
2218 | * @file: file that was modified |
2219 | * |
2220 | * When file has been modified ensure that special |
2221 | * file privileges are removed and time settings are updated. |
2222 | * |
2223 | * Context: Caller must hold the file's inode lock. |
2224 | * |
2225 | * Return: 0 on success, negative errno on failure. |
2226 | */ |
2227 | int file_modified(struct file *file) |
2228 | { |
2229 | return file_modified_flags(file, flags: 0); |
2230 | } |
2231 | EXPORT_SYMBOL(file_modified); |
2232 | |
2233 | /** |
2234 | * kiocb_modified - handle mandated vfs changes when modifying a file |
2235 | * @iocb: iocb that was modified |
2236 | * |
2237 | * When file has been modified ensure that special |
2238 | * file privileges are removed and time settings are updated. |
2239 | * |
2240 | * Context: Caller must hold the file's inode lock. |
2241 | * |
2242 | * Return: 0 on success, negative errno on failure. |
2243 | */ |
2244 | int kiocb_modified(struct kiocb *iocb) |
2245 | { |
2246 | return file_modified_flags(file: iocb->ki_filp, flags: iocb->ki_flags); |
2247 | } |
2248 | EXPORT_SYMBOL_GPL(kiocb_modified); |
2249 | |
2250 | int inode_needs_sync(struct inode *inode) |
2251 | { |
2252 | if (IS_SYNC(inode)) |
2253 | return 1; |
2254 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) |
2255 | return 1; |
2256 | return 0; |
2257 | } |
2258 | EXPORT_SYMBOL(inode_needs_sync); |
2259 | |
2260 | /* |
2261 | * If we try to find an inode in the inode hash while it is being |
2262 | * deleted, we have to wait until the filesystem completes its |
2263 | * deletion before reporting that it isn't found. This function waits |
2264 | * until the deletion _might_ have completed. Callers are responsible |
2265 | * to recheck inode state. |
2266 | * |
2267 | * It doesn't matter if I_NEW is not set initially, a call to |
2268 | * wake_up_bit(&inode->i_state, __I_NEW) after removing from the hash list |
2269 | * will DTRT. |
2270 | */ |
2271 | static void __wait_on_freeing_inode(struct inode *inode) |
2272 | { |
2273 | wait_queue_head_t *wq; |
2274 | DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW); |
2275 | wq = bit_waitqueue(word: &inode->i_state, __I_NEW); |
2276 | prepare_to_wait(wq_head: wq, wq_entry: &wait.wq_entry, TASK_UNINTERRUPTIBLE); |
2277 | spin_unlock(lock: &inode->i_lock); |
2278 | spin_unlock(lock: &inode_hash_lock); |
2279 | schedule(); |
2280 | finish_wait(wq_head: wq, wq_entry: &wait.wq_entry); |
2281 | spin_lock(lock: &inode_hash_lock); |
2282 | } |
2283 | |
2284 | static __initdata unsigned long ihash_entries; |
2285 | static int __init set_ihash_entries(char *str) |
2286 | { |
2287 | if (!str) |
2288 | return 0; |
2289 | ihash_entries = simple_strtoul(str, &str, 0); |
2290 | return 1; |
2291 | } |
2292 | __setup("ihash_entries=" , set_ihash_entries); |
2293 | |
2294 | /* |
2295 | * Initialize the waitqueues and inode hash table. |
2296 | */ |
2297 | void __init inode_init_early(void) |
2298 | { |
2299 | /* If hashes are distributed across NUMA nodes, defer |
2300 | * hash allocation until vmalloc space is available. |
2301 | */ |
2302 | if (hashdist) |
2303 | return; |
2304 | |
2305 | inode_hashtable = |
2306 | alloc_large_system_hash(tablename: "Inode-cache" , |
2307 | bucketsize: sizeof(struct hlist_head), |
2308 | numentries: ihash_entries, |
2309 | scale: 14, |
2310 | HASH_EARLY | HASH_ZERO, |
2311 | hash_shift: &i_hash_shift, |
2312 | hash_mask: &i_hash_mask, |
2313 | low_limit: 0, |
2314 | high_limit: 0); |
2315 | } |
2316 | |
2317 | void __init inode_init(void) |
2318 | { |
2319 | /* inode slab cache */ |
2320 | inode_cachep = kmem_cache_create(name: "inode_cache" , |
2321 | size: sizeof(struct inode), |
2322 | align: 0, |
2323 | flags: (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| |
2324 | SLAB_MEM_SPREAD|SLAB_ACCOUNT), |
2325 | ctor: init_once); |
2326 | |
2327 | /* Hash may have been set up in inode_init_early */ |
2328 | if (!hashdist) |
2329 | return; |
2330 | |
2331 | inode_hashtable = |
2332 | alloc_large_system_hash(tablename: "Inode-cache" , |
2333 | bucketsize: sizeof(struct hlist_head), |
2334 | numentries: ihash_entries, |
2335 | scale: 14, |
2336 | HASH_ZERO, |
2337 | hash_shift: &i_hash_shift, |
2338 | hash_mask: &i_hash_mask, |
2339 | low_limit: 0, |
2340 | high_limit: 0); |
2341 | } |
2342 | |
2343 | void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev) |
2344 | { |
2345 | inode->i_mode = mode; |
2346 | if (S_ISCHR(mode)) { |
2347 | inode->i_fop = &def_chr_fops; |
2348 | inode->i_rdev = rdev; |
2349 | } else if (S_ISBLK(mode)) { |
2350 | if (IS_ENABLED(CONFIG_BLOCK)) |
2351 | inode->i_fop = &def_blk_fops; |
2352 | inode->i_rdev = rdev; |
2353 | } else if (S_ISFIFO(mode)) |
2354 | inode->i_fop = &pipefifo_fops; |
2355 | else if (S_ISSOCK(mode)) |
2356 | ; /* leave it no_open_fops */ |
2357 | else |
2358 | printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for" |
2359 | " inode %s:%lu\n" , mode, inode->i_sb->s_id, |
2360 | inode->i_ino); |
2361 | } |
2362 | EXPORT_SYMBOL(init_special_inode); |
2363 | |
2364 | /** |
2365 | * inode_init_owner - Init uid,gid,mode for new inode according to posix standards |
2366 | * @idmap: idmap of the mount the inode was created from |
2367 | * @inode: New inode |
2368 | * @dir: Directory inode |
2369 | * @mode: mode of the new inode |
2370 | * |
2371 | * If the inode has been created through an idmapped mount the idmap of |
2372 | * the vfsmount must be passed through @idmap. This function will then take |
2373 | * care to map the inode according to @idmap before checking permissions |
2374 | * and initializing i_uid and i_gid. On non-idmapped mounts or if permission |
2375 | * checking is to be performed on the raw inode simply pass @nop_mnt_idmap. |
2376 | */ |
2377 | void inode_init_owner(struct mnt_idmap *idmap, struct inode *inode, |
2378 | const struct inode *dir, umode_t mode) |
2379 | { |
2380 | inode_fsuid_set(inode, idmap); |
2381 | if (dir && dir->i_mode & S_ISGID) { |
2382 | inode->i_gid = dir->i_gid; |
2383 | |
2384 | /* Directories are special, and always inherit S_ISGID */ |
2385 | if (S_ISDIR(mode)) |
2386 | mode |= S_ISGID; |
2387 | } else |
2388 | inode_fsgid_set(inode, idmap); |
2389 | inode->i_mode = mode; |
2390 | } |
2391 | EXPORT_SYMBOL(inode_init_owner); |
2392 | |
2393 | /** |
2394 | * inode_owner_or_capable - check current task permissions to inode |
2395 | * @idmap: idmap of the mount the inode was found from |
2396 | * @inode: inode being checked |
2397 | * |
2398 | * Return true if current either has CAP_FOWNER in a namespace with the |
2399 | * inode owner uid mapped, or owns the file. |
2400 | * |
2401 | * If the inode has been found through an idmapped mount the idmap of |
2402 | * the vfsmount must be passed through @idmap. This function will then take |
2403 | * care to map the inode according to @idmap before checking permissions. |
2404 | * On non-idmapped mounts or if permission checking is to be performed on the |
2405 | * raw inode simply passs @nop_mnt_idmap. |
2406 | */ |
2407 | bool inode_owner_or_capable(struct mnt_idmap *idmap, |
2408 | const struct inode *inode) |
2409 | { |
2410 | vfsuid_t vfsuid; |
2411 | struct user_namespace *ns; |
2412 | |
2413 | vfsuid = i_uid_into_vfsuid(idmap, inode); |
2414 | if (vfsuid_eq_kuid(vfsuid, current_fsuid())) |
2415 | return true; |
2416 | |
2417 | ns = current_user_ns(); |
2418 | if (vfsuid_has_mapping(userns: ns, vfsuid) && ns_capable(ns, CAP_FOWNER)) |
2419 | return true; |
2420 | return false; |
2421 | } |
2422 | EXPORT_SYMBOL(inode_owner_or_capable); |
2423 | |
2424 | /* |
2425 | * Direct i/o helper functions |
2426 | */ |
2427 | static void __inode_dio_wait(struct inode *inode) |
2428 | { |
2429 | wait_queue_head_t *wq = bit_waitqueue(word: &inode->i_state, __I_DIO_WAKEUP); |
2430 | DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP); |
2431 | |
2432 | do { |
2433 | prepare_to_wait(wq_head: wq, wq_entry: &q.wq_entry, TASK_UNINTERRUPTIBLE); |
2434 | if (atomic_read(v: &inode->i_dio_count)) |
2435 | schedule(); |
2436 | } while (atomic_read(v: &inode->i_dio_count)); |
2437 | finish_wait(wq_head: wq, wq_entry: &q.wq_entry); |
2438 | } |
2439 | |
2440 | /** |
2441 | * inode_dio_wait - wait for outstanding DIO requests to finish |
2442 | * @inode: inode to wait for |
2443 | * |
2444 | * Waits for all pending direct I/O requests to finish so that we can |
2445 | * proceed with a truncate or equivalent operation. |
2446 | * |
2447 | * Must be called under a lock that serializes taking new references |
2448 | * to i_dio_count, usually by inode->i_mutex. |
2449 | */ |
2450 | void inode_dio_wait(struct inode *inode) |
2451 | { |
2452 | if (atomic_read(v: &inode->i_dio_count)) |
2453 | __inode_dio_wait(inode); |
2454 | } |
2455 | EXPORT_SYMBOL(inode_dio_wait); |
2456 | |
2457 | /* |
2458 | * inode_set_flags - atomically set some inode flags |
2459 | * |
2460 | * Note: the caller should be holding i_mutex, or else be sure that |
2461 | * they have exclusive access to the inode structure (i.e., while the |
2462 | * inode is being instantiated). The reason for the cmpxchg() loop |
2463 | * --- which wouldn't be necessary if all code paths which modify |
2464 | * i_flags actually followed this rule, is that there is at least one |
2465 | * code path which doesn't today so we use cmpxchg() out of an abundance |
2466 | * of caution. |
2467 | * |
2468 | * In the long run, i_mutex is overkill, and we should probably look |
2469 | * at using the i_lock spinlock to protect i_flags, and then make sure |
2470 | * it is so documented in include/linux/fs.h and that all code follows |
2471 | * the locking convention!! |
2472 | */ |
2473 | void inode_set_flags(struct inode *inode, unsigned int flags, |
2474 | unsigned int mask) |
2475 | { |
2476 | WARN_ON_ONCE(flags & ~mask); |
2477 | set_mask_bits(&inode->i_flags, mask, flags); |
2478 | } |
2479 | EXPORT_SYMBOL(inode_set_flags); |
2480 | |
2481 | void inode_nohighmem(struct inode *inode) |
2482 | { |
2483 | mapping_set_gfp_mask(m: inode->i_mapping, GFP_USER); |
2484 | } |
2485 | EXPORT_SYMBOL(inode_nohighmem); |
2486 | |
2487 | /** |
2488 | * timestamp_truncate - Truncate timespec to a granularity |
2489 | * @t: Timespec |
2490 | * @inode: inode being updated |
2491 | * |
2492 | * Truncate a timespec to the granularity supported by the fs |
2493 | * containing the inode. Always rounds down. gran must |
2494 | * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). |
2495 | */ |
2496 | struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode) |
2497 | { |
2498 | struct super_block *sb = inode->i_sb; |
2499 | unsigned int gran = sb->s_time_gran; |
2500 | |
2501 | t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max); |
2502 | if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min)) |
2503 | t.tv_nsec = 0; |
2504 | |
2505 | /* Avoid division in the common cases 1 ns and 1 s. */ |
2506 | if (gran == 1) |
2507 | ; /* nothing */ |
2508 | else if (gran == NSEC_PER_SEC) |
2509 | t.tv_nsec = 0; |
2510 | else if (gran > 1 && gran < NSEC_PER_SEC) |
2511 | t.tv_nsec -= t.tv_nsec % gran; |
2512 | else |
2513 | WARN(1, "invalid file time granularity: %u" , gran); |
2514 | return t; |
2515 | } |
2516 | EXPORT_SYMBOL(timestamp_truncate); |
2517 | |
2518 | /** |
2519 | * current_time - Return FS time |
2520 | * @inode: inode. |
2521 | * |
2522 | * Return the current time truncated to the time granularity supported by |
2523 | * the fs. |
2524 | * |
2525 | * Note that inode and inode->sb cannot be NULL. |
2526 | * Otherwise, the function warns and returns time without truncation. |
2527 | */ |
2528 | struct timespec64 current_time(struct inode *inode) |
2529 | { |
2530 | struct timespec64 now; |
2531 | |
2532 | ktime_get_coarse_real_ts64(ts: &now); |
2533 | return timestamp_truncate(now, inode); |
2534 | } |
2535 | EXPORT_SYMBOL(current_time); |
2536 | |
2537 | /** |
2538 | * inode_set_ctime_current - set the ctime to current_time |
2539 | * @inode: inode |
2540 | * |
2541 | * Set the inode->i_ctime to the current value for the inode. Returns |
2542 | * the current value that was assigned to i_ctime. |
2543 | */ |
2544 | struct timespec64 inode_set_ctime_current(struct inode *inode) |
2545 | { |
2546 | struct timespec64 now = current_time(inode); |
2547 | |
2548 | inode_set_ctime(inode, sec: now.tv_sec, nsec: now.tv_nsec); |
2549 | return now; |
2550 | } |
2551 | EXPORT_SYMBOL(inode_set_ctime_current); |
2552 | |
2553 | /** |
2554 | * in_group_or_capable - check whether caller is CAP_FSETID privileged |
2555 | * @idmap: idmap of the mount @inode was found from |
2556 | * @inode: inode to check |
2557 | * @vfsgid: the new/current vfsgid of @inode |
2558 | * |
2559 | * Check wether @vfsgid is in the caller's group list or if the caller is |
2560 | * privileged with CAP_FSETID over @inode. This can be used to determine |
2561 | * whether the setgid bit can be kept or must be dropped. |
2562 | * |
2563 | * Return: true if the caller is sufficiently privileged, false if not. |
2564 | */ |
2565 | bool in_group_or_capable(struct mnt_idmap *idmap, |
2566 | const struct inode *inode, vfsgid_t vfsgid) |
2567 | { |
2568 | if (vfsgid_in_group_p(vfsgid)) |
2569 | return true; |
2570 | if (capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID)) |
2571 | return true; |
2572 | return false; |
2573 | } |
2574 | |
2575 | /** |
2576 | * mode_strip_sgid - handle the sgid bit for non-directories |
2577 | * @idmap: idmap of the mount the inode was created from |
2578 | * @dir: parent directory inode |
2579 | * @mode: mode of the file to be created in @dir |
2580 | * |
2581 | * If the @mode of the new file has both the S_ISGID and S_IXGRP bit |
2582 | * raised and @dir has the S_ISGID bit raised ensure that the caller is |
2583 | * either in the group of the parent directory or they have CAP_FSETID |
2584 | * in their user namespace and are privileged over the parent directory. |
2585 | * In all other cases, strip the S_ISGID bit from @mode. |
2586 | * |
2587 | * Return: the new mode to use for the file |
2588 | */ |
2589 | umode_t mode_strip_sgid(struct mnt_idmap *idmap, |
2590 | const struct inode *dir, umode_t mode) |
2591 | { |
2592 | if ((mode & (S_ISGID | S_IXGRP)) != (S_ISGID | S_IXGRP)) |
2593 | return mode; |
2594 | if (S_ISDIR(mode) || !dir || !(dir->i_mode & S_ISGID)) |
2595 | return mode; |
2596 | if (in_group_or_capable(idmap, inode: dir, vfsgid: i_gid_into_vfsgid(idmap, inode: dir))) |
2597 | return mode; |
2598 | return mode & ~S_ISGID; |
2599 | } |
2600 | EXPORT_SYMBOL(mode_strip_sgid); |
2601 | |