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