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