Line data Source code
1 : /*
2 : * Resizable virtual memory filesystem for Linux.
3 : *
4 : * Copyright (C) 2000 Linus Torvalds.
5 : * 2000 Transmeta Corp.
6 : * 2000-2001 Christoph Rohland
7 : * 2000-2001 SAP AG
8 : * 2002 Red Hat Inc.
9 : * Copyright (C) 2002-2011 Hugh Dickins.
10 : * Copyright (C) 2011 Google Inc.
11 : * Copyright (C) 2002-2005 VERITAS Software Corporation.
12 : * Copyright (C) 2004 Andi Kleen, SuSE Labs
13 : *
14 : * Extended attribute support for tmpfs:
15 : * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
16 : * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
17 : *
18 : * tiny-shmem:
19 : * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
20 : *
21 : * This file is released under the GPL.
22 : */
23 :
24 : #include <linux/fs.h>
25 : #include <linux/init.h>
26 : #include <linux/vfs.h>
27 : #include <linux/mount.h>
28 : #include <linux/ramfs.h>
29 : #include <linux/pagemap.h>
30 : #include <linux/file.h>
31 : #include <linux/mm.h>
32 : #include <linux/random.h>
33 : #include <linux/sched/signal.h>
34 : #include <linux/export.h>
35 : #include <linux/swap.h>
36 : #include <linux/uio.h>
37 : #include <linux/khugepaged.h>
38 : #include <linux/hugetlb.h>
39 : #include <linux/frontswap.h>
40 : #include <linux/fs_parser.h>
41 :
42 : #include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */
43 :
44 : static struct vfsmount *shm_mnt;
45 :
46 : #ifdef CONFIG_SHMEM
47 : /*
48 : * This virtual memory filesystem is heavily based on the ramfs. It
49 : * extends ramfs by the ability to use swap and honor resource limits
50 : * which makes it a completely usable filesystem.
51 : */
52 :
53 : #include <linux/xattr.h>
54 : #include <linux/exportfs.h>
55 : #include <linux/posix_acl.h>
56 : #include <linux/posix_acl_xattr.h>
57 : #include <linux/mman.h>
58 : #include <linux/string.h>
59 : #include <linux/slab.h>
60 : #include <linux/backing-dev.h>
61 : #include <linux/shmem_fs.h>
62 : #include <linux/writeback.h>
63 : #include <linux/blkdev.h>
64 : #include <linux/pagevec.h>
65 : #include <linux/percpu_counter.h>
66 : #include <linux/falloc.h>
67 : #include <linux/splice.h>
68 : #include <linux/security.h>
69 : #include <linux/swapops.h>
70 : #include <linux/mempolicy.h>
71 : #include <linux/namei.h>
72 : #include <linux/ctype.h>
73 : #include <linux/migrate.h>
74 : #include <linux/highmem.h>
75 : #include <linux/seq_file.h>
76 : #include <linux/magic.h>
77 : #include <linux/syscalls.h>
78 : #include <linux/fcntl.h>
79 : #include <uapi/linux/memfd.h>
80 : #include <linux/userfaultfd_k.h>
81 : #include <linux/rmap.h>
82 : #include <linux/uuid.h>
83 :
84 : #include <linux/uaccess.h>
85 :
86 : #include "internal.h"
87 :
88 : #define BLOCKS_PER_PAGE (PAGE_SIZE/512)
89 : #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
90 :
91 : /* Pretend that each entry is of this size in directory's i_size */
92 : #define BOGO_DIRENT_SIZE 20
93 :
94 : /* Symlink up to this size is kmalloc'ed instead of using a swappable page */
95 : #define SHORT_SYMLINK_LEN 128
96 :
97 : /*
98 : * shmem_fallocate communicates with shmem_fault or shmem_writepage via
99 : * inode->i_private (with i_mutex making sure that it has only one user at
100 : * a time): we would prefer not to enlarge the shmem inode just for that.
101 : */
102 : struct shmem_falloc {
103 : wait_queue_head_t *waitq; /* faults into hole wait for punch to end */
104 : pgoff_t start; /* start of range currently being fallocated */
105 : pgoff_t next; /* the next page offset to be fallocated */
106 : pgoff_t nr_falloced; /* how many new pages have been fallocated */
107 : pgoff_t nr_unswapped; /* how often writepage refused to swap out */
108 : };
109 :
110 : struct shmem_options {
111 : unsigned long long blocks;
112 : unsigned long long inodes;
113 : struct mempolicy *mpol;
114 : kuid_t uid;
115 : kgid_t gid;
116 : umode_t mode;
117 : bool full_inums;
118 : int huge;
119 : int seen;
120 : #define SHMEM_SEEN_BLOCKS 1
121 : #define SHMEM_SEEN_INODES 2
122 : #define SHMEM_SEEN_HUGE 4
123 : #define SHMEM_SEEN_INUMS 8
124 : };
125 :
126 : #ifdef CONFIG_TMPFS
127 1920 : static unsigned long shmem_default_max_blocks(void)
128 : {
129 3838 : return totalram_pages() / 2;
130 : }
131 :
132 2015 : static unsigned long shmem_default_max_inodes(void)
133 : {
134 2015 : unsigned long nr_pages = totalram_pages();
135 :
136 2015 : return min(nr_pages - totalhigh_pages(), nr_pages / 2);
137 : }
138 : #endif
139 :
140 : static bool shmem_should_replace_page(struct page *page, gfp_t gfp);
141 : static int shmem_replace_page(struct page **pagep, gfp_t gfp,
142 : struct shmem_inode_info *info, pgoff_t index);
143 : static int shmem_swapin_page(struct inode *inode, pgoff_t index,
144 : struct page **pagep, enum sgp_type sgp,
145 : gfp_t gfp, struct vm_area_struct *vma,
146 : vm_fault_t *fault_type);
147 : static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
148 : struct page **pagep, enum sgp_type sgp,
149 : gfp_t gfp, struct vm_area_struct *vma,
150 : struct vm_fault *vmf, vm_fault_t *fault_type);
151 :
152 2175 : int shmem_getpage(struct inode *inode, pgoff_t index,
153 : struct page **pagep, enum sgp_type sgp)
154 : {
155 2175 : return shmem_getpage_gfp(inode, index, pagep, sgp,
156 : mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL);
157 : }
158 :
159 13213 : static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
160 : {
161 13213 : return sb->s_fs_info;
162 : }
163 :
164 : /*
165 : * shmem_file_setup pre-accounts the whole fixed size of a VM object,
166 : * for shared memory and for shared anonymous (/dev/zero) mappings
167 : * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
168 : * consistent with the pre-accounting of private mappings ...
169 : */
170 6 : static inline int shmem_acct_size(unsigned long flags, loff_t size)
171 : {
172 6 : return (flags & VM_NORESERVE) ?
173 6 : 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size));
174 : }
175 :
176 586 : static inline void shmem_unacct_size(unsigned long flags, loff_t size)
177 : {
178 586 : if (!(flags & VM_NORESERVE))
179 3 : vm_unacct_memory(VM_ACCT(size));
180 586 : }
181 :
182 2 : static inline int shmem_reacct_size(unsigned long flags,
183 : loff_t oldsize, loff_t newsize)
184 : {
185 2 : if (!(flags & VM_NORESERVE)) {
186 0 : if (VM_ACCT(newsize) > VM_ACCT(oldsize))
187 0 : return security_vm_enough_memory_mm(current->mm,
188 0 : VM_ACCT(newsize) - VM_ACCT(oldsize));
189 0 : else if (VM_ACCT(newsize) < VM_ACCT(oldsize))
190 0 : vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize));
191 : }
192 : return 0;
193 : }
194 :
195 : /*
196 : * ... whereas tmpfs objects are accounted incrementally as
197 : * pages are allocated, in order to allow large sparse files.
198 : * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
199 : * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
200 : */
201 1985 : static inline int shmem_acct_block(unsigned long flags, long pages)
202 : {
203 1985 : if (!(flags & VM_NORESERVE))
204 : return 0;
205 :
206 1982 : return security_vm_enough_memory_mm(current->mm,
207 : pages * VM_ACCT(PAGE_SIZE));
208 : }
209 :
210 95 : static inline void shmem_unacct_blocks(unsigned long flags, long pages)
211 : {
212 95 : if (flags & VM_NORESERVE)
213 92 : vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));
214 : }
215 :
216 1985 : static inline bool shmem_inode_acct_block(struct inode *inode, long pages)
217 : {
218 1985 : struct shmem_inode_info *info = SHMEM_I(inode);
219 1985 : struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
220 :
221 1985 : if (shmem_acct_block(info->flags, pages))
222 : return false;
223 :
224 1985 : if (sbinfo->max_blocks) {
225 1982 : if (percpu_counter_compare(&sbinfo->used_blocks,
226 1982 : sbinfo->max_blocks - pages) > 0)
227 0 : goto unacct;
228 1982 : percpu_counter_add(&sbinfo->used_blocks, pages);
229 : }
230 :
231 : return true;
232 :
233 0 : unacct:
234 0 : shmem_unacct_blocks(info->flags, pages);
235 : return false;
236 : }
237 :
238 95 : static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages)
239 : {
240 95 : struct shmem_inode_info *info = SHMEM_I(inode);
241 95 : struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
242 :
243 95 : if (sbinfo->max_blocks)
244 92 : percpu_counter_sub(&sbinfo->used_blocks, pages);
245 95 : shmem_unacct_blocks(info->flags, pages);
246 95 : }
247 :
248 : static const struct super_operations shmem_ops;
249 : const struct address_space_operations shmem_aops;
250 : static const struct file_operations shmem_file_operations;
251 : static const struct inode_operations shmem_inode_operations;
252 : static const struct inode_operations shmem_dir_inode_operations;
253 : static const struct inode_operations shmem_special_inode_operations;
254 : static const struct vm_operations_struct shmem_vm_ops;
255 : static struct file_system_type shmem_fs_type;
256 :
257 0 : bool vma_is_shmem(struct vm_area_struct *vma)
258 : {
259 0 : return vma->vm_ops == &shmem_vm_ops;
260 : }
261 :
262 : static LIST_HEAD(shmem_swaplist);
263 : static DEFINE_MUTEX(shmem_swaplist_mutex);
264 :
265 : /*
266 : * shmem_reserve_inode() performs bookkeeping to reserve a shmem inode, and
267 : * produces a novel ino for the newly allocated inode.
268 : *
269 : * It may also be called when making a hard link to permit the space needed by
270 : * each dentry. However, in that case, no new inode number is needed since that
271 : * internally draws from another pool of inode numbers (currently global
272 : * get_next_ino()). This case is indicated by passing NULL as inop.
273 : */
274 : #define SHMEM_INO_BATCH 1024
275 1760 : static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
276 : {
277 1760 : struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
278 1760 : ino_t ino;
279 :
280 1760 : if (!(sb->s_flags & SB_KERNMOUNT)) {
281 1753 : spin_lock(&sbinfo->stat_lock);
282 1753 : if (sbinfo->max_inodes) {
283 1753 : if (!sbinfo->free_inodes) {
284 0 : spin_unlock(&sbinfo->stat_lock);
285 0 : return -ENOSPC;
286 : }
287 1753 : sbinfo->free_inodes--;
288 : }
289 1753 : if (inop) {
290 1737 : ino = sbinfo->next_ino++;
291 1737 : if (unlikely(is_zero_ino(ino)))
292 102 : ino = sbinfo->next_ino++;
293 1737 : if (unlikely(!sbinfo->full_inums &&
294 : ino > UINT_MAX)) {
295 : /*
296 : * Emulate get_next_ino uint wraparound for
297 : * compatibility
298 : */
299 0 : if (IS_ENABLED(CONFIG_64BIT))
300 0 : pr_warn("%s: inode number overflow on device %d, consider using inode64 mount option\n",
301 : __func__, MINOR(sb->s_dev));
302 0 : sbinfo->next_ino = 1;
303 0 : ino = sbinfo->next_ino++;
304 : }
305 1737 : *inop = ino;
306 : }
307 1753 : spin_unlock(&sbinfo->stat_lock);
308 7 : } else if (inop) {
309 : /*
310 : * __shmem_file_setup, one of our callers, is lock-free: it
311 : * doesn't hold stat_lock in shmem_reserve_inode since
312 : * max_inodes is always 0, and is called from potentially
313 : * unknown contexts. As such, use a per-cpu batched allocator
314 : * which doesn't require the per-sb stat_lock unless we are at
315 : * the batch boundary.
316 : *
317 : * We don't need to worry about inode{32,64} since SB_KERNMOUNT
318 : * shmem mounts are not exposed to userspace, so we don't need
319 : * to worry about things like glibc compatibility.
320 : */
321 7 : ino_t *next_ino;
322 7 : next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu());
323 7 : ino = *next_ino;
324 7 : if (unlikely(ino % SHMEM_INO_BATCH == 0)) {
325 4 : spin_lock(&sbinfo->stat_lock);
326 4 : ino = sbinfo->next_ino;
327 4 : sbinfo->next_ino += SHMEM_INO_BATCH;
328 4 : spin_unlock(&sbinfo->stat_lock);
329 4 : if (unlikely(is_zero_ino(ino)))
330 1 : ino++;
331 : }
332 7 : *inop = ino;
333 7 : *next_ino = ++ino;
334 7 : put_cpu();
335 : }
336 :
337 : return 0;
338 : }
339 :
340 1178 : static void shmem_free_inode(struct super_block *sb)
341 : {
342 1178 : struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
343 1178 : if (sbinfo->max_inodes) {
344 1172 : spin_lock(&sbinfo->stat_lock);
345 1172 : sbinfo->free_inodes++;
346 1172 : spin_unlock(&sbinfo->stat_lock);
347 : }
348 1178 : }
349 :
350 : /**
351 : * shmem_recalc_inode - recalculate the block usage of an inode
352 : * @inode: inode to recalc
353 : *
354 : * We have to calculate the free blocks since the mm can drop
355 : * undirtied hole pages behind our back.
356 : *
357 : * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
358 : * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
359 : *
360 : * It has to be called with the spinlock held.
361 : */
362 2617 : static void shmem_recalc_inode(struct inode *inode)
363 : {
364 2617 : struct shmem_inode_info *info = SHMEM_I(inode);
365 2617 : long freed;
366 :
367 2617 : freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
368 2617 : if (freed > 0) {
369 95 : info->alloced -= freed;
370 95 : inode->i_blocks -= freed * BLOCKS_PER_PAGE;
371 95 : shmem_inode_unacct_blocks(inode, freed);
372 : }
373 2617 : }
374 :
375 0 : bool shmem_charge(struct inode *inode, long pages)
376 : {
377 0 : struct shmem_inode_info *info = SHMEM_I(inode);
378 0 : unsigned long flags;
379 :
380 0 : if (!shmem_inode_acct_block(inode, pages))
381 : return false;
382 :
383 : /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
384 0 : inode->i_mapping->nrpages += pages;
385 :
386 0 : spin_lock_irqsave(&info->lock, flags);
387 0 : info->alloced += pages;
388 0 : inode->i_blocks += pages * BLOCKS_PER_PAGE;
389 0 : shmem_recalc_inode(inode);
390 0 : spin_unlock_irqrestore(&info->lock, flags);
391 :
392 0 : return true;
393 : }
394 :
395 0 : void shmem_uncharge(struct inode *inode, long pages)
396 : {
397 0 : struct shmem_inode_info *info = SHMEM_I(inode);
398 0 : unsigned long flags;
399 :
400 : /* nrpages adjustment done by __delete_from_page_cache() or caller */
401 :
402 0 : spin_lock_irqsave(&info->lock, flags);
403 0 : info->alloced -= pages;
404 0 : inode->i_blocks -= pages * BLOCKS_PER_PAGE;
405 0 : shmem_recalc_inode(inode);
406 0 : spin_unlock_irqrestore(&info->lock, flags);
407 :
408 0 : shmem_inode_unacct_blocks(inode, pages);
409 0 : }
410 :
411 : /*
412 : * Replace item expected in xarray by a new item, while holding xa_lock.
413 : */
414 : static int shmem_replace_entry(struct address_space *mapping,
415 : pgoff_t index, void *expected, void *replacement)
416 : {
417 : XA_STATE(xas, &mapping->i_pages, index);
418 : void *item;
419 :
420 : VM_BUG_ON(!expected);
421 : VM_BUG_ON(!replacement);
422 : item = xas_load(&xas);
423 : if (item != expected)
424 : return -ENOENT;
425 : xas_store(&xas, replacement);
426 : return 0;
427 : }
428 :
429 : /*
430 : * Sometimes, before we decide whether to proceed or to fail, we must check
431 : * that an entry was not already brought back from swap by a racing thread.
432 : *
433 : * Checking page is not enough: by the time a SwapCache page is locked, it
434 : * might be reused, and again be SwapCache, using the same swap as before.
435 : */
436 0 : static bool shmem_confirm_swap(struct address_space *mapping,
437 : pgoff_t index, swp_entry_t swap)
438 : {
439 0 : return xa_load(&mapping->i_pages, index) == swp_to_radix_entry(swap);
440 : }
441 :
442 : /*
443 : * Definitions for "huge tmpfs": tmpfs mounted with the huge= option
444 : *
445 : * SHMEM_HUGE_NEVER:
446 : * disables huge pages for the mount;
447 : * SHMEM_HUGE_ALWAYS:
448 : * enables huge pages for the mount;
449 : * SHMEM_HUGE_WITHIN_SIZE:
450 : * only allocate huge pages if the page will be fully within i_size,
451 : * also respect fadvise()/madvise() hints;
452 : * SHMEM_HUGE_ADVISE:
453 : * only allocate huge pages if requested with fadvise()/madvise();
454 : */
455 :
456 : #define SHMEM_HUGE_NEVER 0
457 : #define SHMEM_HUGE_ALWAYS 1
458 : #define SHMEM_HUGE_WITHIN_SIZE 2
459 : #define SHMEM_HUGE_ADVISE 3
460 :
461 : /*
462 : * Special values.
463 : * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
464 : *
465 : * SHMEM_HUGE_DENY:
466 : * disables huge on shm_mnt and all mounts, for emergency use;
467 : * SHMEM_HUGE_FORCE:
468 : * enables huge on shm_mnt and all mounts, w/o needing option, for testing;
469 : *
470 : */
471 : #define SHMEM_HUGE_DENY (-1)
472 : #define SHMEM_HUGE_FORCE (-2)
473 :
474 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
475 : /* ifdef here to avoid bloating shmem.o when not necessary */
476 :
477 : static int shmem_huge __read_mostly;
478 :
479 : #if defined(CONFIG_SYSFS)
480 0 : static int shmem_parse_huge(const char *str)
481 : {
482 0 : if (!strcmp(str, "never"))
483 : return SHMEM_HUGE_NEVER;
484 0 : if (!strcmp(str, "always"))
485 : return SHMEM_HUGE_ALWAYS;
486 0 : if (!strcmp(str, "within_size"))
487 : return SHMEM_HUGE_WITHIN_SIZE;
488 0 : if (!strcmp(str, "advise"))
489 : return SHMEM_HUGE_ADVISE;
490 0 : if (!strcmp(str, "deny"))
491 : return SHMEM_HUGE_DENY;
492 0 : if (!strcmp(str, "force"))
493 0 : return SHMEM_HUGE_FORCE;
494 : return -EINVAL;
495 : }
496 : #endif
497 :
498 : #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
499 0 : static const char *shmem_format_huge(int huge)
500 : {
501 0 : switch (huge) {
502 : case SHMEM_HUGE_NEVER:
503 : return "never";
504 : case SHMEM_HUGE_ALWAYS:
505 : return "always";
506 : case SHMEM_HUGE_WITHIN_SIZE:
507 : return "within_size";
508 : case SHMEM_HUGE_ADVISE:
509 : return "advise";
510 : case SHMEM_HUGE_DENY:
511 : return "deny";
512 : case SHMEM_HUGE_FORCE:
513 : return "force";
514 : default:
515 0 : VM_BUG_ON(1);
516 : return "bad_val";
517 : }
518 : }
519 : #endif
520 :
521 0 : static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
522 : struct shrink_control *sc, unsigned long nr_to_split)
523 : {
524 0 : LIST_HEAD(list), *pos, *next;
525 0 : LIST_HEAD(to_remove);
526 0 : struct inode *inode;
527 0 : struct shmem_inode_info *info;
528 0 : struct page *page;
529 0 : unsigned long batch = sc ? sc->nr_to_scan : 128;
530 0 : int removed = 0, split = 0;
531 :
532 0 : if (list_empty(&sbinfo->shrinklist))
533 : return SHRINK_STOP;
534 :
535 0 : spin_lock(&sbinfo->shrinklist_lock);
536 0 : list_for_each_safe(pos, next, &sbinfo->shrinklist) {
537 0 : info = list_entry(pos, struct shmem_inode_info, shrinklist);
538 :
539 : /* pin the inode */
540 0 : inode = igrab(&info->vfs_inode);
541 :
542 : /* inode is about to be evicted */
543 0 : if (!inode) {
544 0 : list_del_init(&info->shrinklist);
545 0 : removed++;
546 0 : goto next;
547 : }
548 :
549 : /* Check if there's anything to gain */
550 0 : if (round_up(inode->i_size, PAGE_SIZE) ==
551 0 : round_up(inode->i_size, HPAGE_PMD_SIZE)) {
552 0 : list_move(&info->shrinklist, &to_remove);
553 0 : removed++;
554 0 : goto next;
555 : }
556 :
557 0 : list_move(&info->shrinklist, &list);
558 0 : next:
559 0 : if (!--batch)
560 : break;
561 : }
562 0 : spin_unlock(&sbinfo->shrinklist_lock);
563 :
564 0 : list_for_each_safe(pos, next, &to_remove) {
565 0 : info = list_entry(pos, struct shmem_inode_info, shrinklist);
566 0 : inode = &info->vfs_inode;
567 0 : list_del_init(&info->shrinklist);
568 0 : iput(inode);
569 : }
570 :
571 0 : list_for_each_safe(pos, next, &list) {
572 0 : int ret;
573 :
574 0 : info = list_entry(pos, struct shmem_inode_info, shrinklist);
575 0 : inode = &info->vfs_inode;
576 :
577 0 : if (nr_to_split && split >= nr_to_split)
578 0 : goto leave;
579 :
580 0 : page = find_get_page(inode->i_mapping,
581 0 : (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT);
582 0 : if (!page)
583 0 : goto drop;
584 :
585 : /* No huge page at the end of the file: nothing to split */
586 0 : if (!PageTransHuge(page)) {
587 0 : put_page(page);
588 0 : goto drop;
589 : }
590 :
591 : /*
592 : * Leave the inode on the list if we failed to lock
593 : * the page at this time.
594 : *
595 : * Waiting for the lock may lead to deadlock in the
596 : * reclaim path.
597 : */
598 0 : if (!trylock_page(page)) {
599 0 : put_page(page);
600 0 : goto leave;
601 : }
602 :
603 0 : ret = split_huge_page(page);
604 0 : unlock_page(page);
605 0 : put_page(page);
606 :
607 : /* If split failed leave the inode on the list */
608 0 : if (ret)
609 0 : goto leave;
610 :
611 0 : split++;
612 0 : drop:
613 0 : list_del_init(&info->shrinklist);
614 0 : removed++;
615 0 : leave:
616 0 : iput(inode);
617 : }
618 :
619 0 : spin_lock(&sbinfo->shrinklist_lock);
620 0 : list_splice_tail(&list, &sbinfo->shrinklist);
621 0 : sbinfo->shrinklist_len -= removed;
622 0 : spin_unlock(&sbinfo->shrinklist_lock);
623 :
624 0 : return split;
625 : }
626 :
627 0 : static long shmem_unused_huge_scan(struct super_block *sb,
628 : struct shrink_control *sc)
629 : {
630 0 : struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
631 :
632 0 : if (!READ_ONCE(sbinfo->shrinklist_len))
633 : return SHRINK_STOP;
634 :
635 0 : return shmem_unused_huge_shrink(sbinfo, sc, 0);
636 : }
637 :
638 0 : static long shmem_unused_huge_count(struct super_block *sb,
639 : struct shrink_control *sc)
640 : {
641 0 : struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
642 0 : return READ_ONCE(sbinfo->shrinklist_len);
643 : }
644 : #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
645 :
646 : #define shmem_huge SHMEM_HUGE_DENY
647 :
648 : static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
649 : struct shrink_control *sc, unsigned long nr_to_split)
650 : {
651 : return 0;
652 : }
653 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
654 :
655 521 : static inline bool is_huge_enabled(struct shmem_sb_info *sbinfo)
656 : {
657 1042 : if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
658 521 : (shmem_huge == SHMEM_HUGE_FORCE || sbinfo->huge) &&
659 : shmem_huge != SHMEM_HUGE_DENY)
660 0 : return true;
661 : return false;
662 : }
663 :
664 : /*
665 : * Like add_to_page_cache_locked, but error if expected item has gone.
666 : */
667 1985 : static int shmem_add_to_page_cache(struct page *page,
668 : struct address_space *mapping,
669 : pgoff_t index, void *expected, gfp_t gfp,
670 : struct mm_struct *charge_mm)
671 : {
672 1985 : XA_STATE_ORDER(xas, &mapping->i_pages, index, compound_order(page));
673 1985 : unsigned long i = 0;
674 1985 : unsigned long nr = compound_nr(page);
675 1985 : int error;
676 :
677 1985 : VM_BUG_ON_PAGE(PageTail(page), page);
678 1985 : VM_BUG_ON_PAGE(index != round_down(index, nr), page);
679 3970 : VM_BUG_ON_PAGE(!PageLocked(page), page);
680 3970 : VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
681 1985 : VM_BUG_ON(expected && PageTransHuge(page));
682 :
683 1985 : page_ref_add(page, nr);
684 1985 : page->mapping = mapping;
685 1985 : page->index = index;
686 :
687 1985 : if (!PageSwapCache(page)) {
688 1985 : error = mem_cgroup_charge(page, charge_mm, gfp);
689 1985 : if (error) {
690 : if (PageTransHuge(page)) {
691 : count_vm_event(THP_FILE_FALLBACK);
692 : count_vm_event(THP_FILE_FALLBACK_CHARGE);
693 : }
694 : goto error;
695 : }
696 : }
697 1985 : cgroup_throttle_swaprate(page, gfp);
698 :
699 1985 : do {
700 1985 : void *entry;
701 1985 : xas_lock_irq(&xas);
702 1985 : entry = xas_find_conflict(&xas);
703 1985 : if (entry != expected)
704 0 : xas_set_err(&xas, -EEXIST);
705 1985 : xas_create_range(&xas);
706 1985 : if (xas_error(&xas))
707 0 : goto unlock;
708 0 : next:
709 1985 : xas_store(&xas, page);
710 1985 : if (++i < nr) {
711 0 : xas_next(&xas);
712 0 : goto next;
713 : }
714 1985 : if (PageTransHuge(page)) {
715 0 : count_vm_event(THP_FILE_ALLOC);
716 0 : __mod_lruvec_page_state(page, NR_SHMEM_THPS, nr);
717 : }
718 1985 : mapping->nrpages += nr;
719 1985 : __mod_lruvec_page_state(page, NR_FILE_PAGES, nr);
720 1985 : __mod_lruvec_page_state(page, NR_SHMEM, nr);
721 1985 : unlock:
722 1985 : xas_unlock_irq(&xas);
723 1985 : } while (xas_nomem(&xas, gfp));
724 :
725 1985 : if (xas_error(&xas)) {
726 0 : error = xas_error(&xas);
727 0 : goto error;
728 : }
729 :
730 : return 0;
731 0 : error:
732 0 : page->mapping = NULL;
733 0 : page_ref_sub(page, nr);
734 0 : return error;
735 : }
736 :
737 : /*
738 : * Like delete_from_page_cache, but substitutes swap for page.
739 : */
740 : static void shmem_delete_from_page_cache(struct page *page, void *radswap)
741 : {
742 : struct address_space *mapping = page->mapping;
743 : int error;
744 :
745 : VM_BUG_ON_PAGE(PageCompound(page), page);
746 :
747 : xa_lock_irq(&mapping->i_pages);
748 : error = shmem_replace_entry(mapping, page->index, page, radswap);
749 : page->mapping = NULL;
750 : mapping->nrpages--;
751 : __dec_lruvec_page_state(page, NR_FILE_PAGES);
752 : __dec_lruvec_page_state(page, NR_SHMEM);
753 : xa_unlock_irq(&mapping->i_pages);
754 : put_page(page);
755 : BUG_ON(error);
756 : }
757 :
758 : /*
759 : * Remove swap entry from page cache, free the swap and its page cache.
760 : */
761 0 : static int shmem_free_swap(struct address_space *mapping,
762 : pgoff_t index, void *radswap)
763 : {
764 0 : void *old;
765 :
766 0 : old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0);
767 0 : if (old != radswap)
768 : return -ENOENT;
769 0 : free_swap_and_cache(radix_to_swp_entry(radswap));
770 : return 0;
771 : }
772 :
773 : /*
774 : * Determine (in bytes) how many of the shmem object's pages mapped by the
775 : * given offsets are swapped out.
776 : *
777 : * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
778 : * as long as the inode doesn't go away and racy results are not a problem.
779 : */
780 0 : unsigned long shmem_partial_swap_usage(struct address_space *mapping,
781 : pgoff_t start, pgoff_t end)
782 : {
783 0 : XA_STATE(xas, &mapping->i_pages, start);
784 0 : struct page *page;
785 0 : unsigned long swapped = 0;
786 :
787 0 : rcu_read_lock();
788 0 : xas_for_each(&xas, page, end - 1) {
789 0 : if (xas_retry(&xas, page))
790 0 : continue;
791 0 : if (xa_is_value(page))
792 0 : swapped++;
793 :
794 0 : if (need_resched()) {
795 0 : xas_pause(&xas);
796 0 : cond_resched_rcu();
797 : }
798 : }
799 :
800 0 : rcu_read_unlock();
801 :
802 0 : return swapped << PAGE_SHIFT;
803 : }
804 :
805 : /*
806 : * Determine (in bytes) how many of the shmem object's pages mapped by the
807 : * given vma is swapped out.
808 : *
809 : * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
810 : * as long as the inode doesn't go away and racy results are not a problem.
811 : */
812 0 : unsigned long shmem_swap_usage(struct vm_area_struct *vma)
813 : {
814 0 : struct inode *inode = file_inode(vma->vm_file);
815 0 : struct shmem_inode_info *info = SHMEM_I(inode);
816 0 : struct address_space *mapping = inode->i_mapping;
817 0 : unsigned long swapped;
818 :
819 : /* Be careful as we don't hold info->lock */
820 0 : swapped = READ_ONCE(info->swapped);
821 :
822 : /*
823 : * The easier cases are when the shmem object has nothing in swap, or
824 : * the vma maps it whole. Then we can simply use the stats that we
825 : * already track.
826 : */
827 0 : if (!swapped)
828 : return 0;
829 :
830 0 : if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size)
831 0 : return swapped << PAGE_SHIFT;
832 :
833 : /* Here comes the more involved part */
834 0 : return shmem_partial_swap_usage(mapping,
835 : linear_page_index(vma, vma->vm_start),
836 : linear_page_index(vma, vma->vm_end));
837 : }
838 :
839 : /*
840 : * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
841 : */
842 0 : void shmem_unlock_mapping(struct address_space *mapping)
843 : {
844 0 : struct pagevec pvec;
845 0 : pgoff_t index = 0;
846 :
847 0 : pagevec_init(&pvec);
848 : /*
849 : * Minor point, but we might as well stop if someone else SHM_LOCKs it.
850 : */
851 0 : while (!mapping_unevictable(mapping)) {
852 0 : if (!pagevec_lookup(&pvec, mapping, &index))
853 : break;
854 0 : check_move_unevictable_pages(&pvec);
855 0 : pagevec_release(&pvec);
856 0 : cond_resched();
857 : }
858 0 : }
859 :
860 : /*
861 : * Check whether a hole-punch or truncation needs to split a huge page,
862 : * returning true if no split was required, or the split has been successful.
863 : *
864 : * Eviction (or truncation to 0 size) should never need to split a huge page;
865 : * but in rare cases might do so, if shmem_undo_range() failed to trylock on
866 : * head, and then succeeded to trylock on tail.
867 : *
868 : * A split can only succeed when there are no additional references on the
869 : * huge page: so the split below relies upon find_get_entries() having stopped
870 : * when it found a subpage of the huge page, without getting further references.
871 : */
872 0 : static bool shmem_punch_compound(struct page *page, pgoff_t start, pgoff_t end)
873 : {
874 0 : if (!PageTransCompound(page))
875 : return true;
876 :
877 : /* Just proceed to delete a huge page wholly within the range punched */
878 0 : if (PageHead(page) &&
879 0 : page->index >= start && page->index + HPAGE_PMD_NR <= end)
880 : return true;
881 :
882 : /* Try to split huge page, so we can truly punch the hole or truncate */
883 0 : return split_huge_page(page) >= 0;
884 : }
885 :
886 : /*
887 : * Remove range of pages and swap entries from page cache, and free them.
888 : * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
889 : */
890 632 : static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
891 : bool unfalloc)
892 : {
893 632 : struct address_space *mapping = inode->i_mapping;
894 632 : struct shmem_inode_info *info = SHMEM_I(inode);
895 632 : pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
896 632 : pgoff_t end = (lend + 1) >> PAGE_SHIFT;
897 632 : unsigned int partial_start = lstart & (PAGE_SIZE - 1);
898 632 : unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1);
899 632 : struct pagevec pvec;
900 632 : pgoff_t indices[PAGEVEC_SIZE];
901 632 : long nr_swaps_freed = 0;
902 632 : pgoff_t index;
903 632 : int i;
904 :
905 632 : if (lend == -1)
906 632 : end = -1; /* unsigned, so actually very big */
907 :
908 632 : pagevec_init(&pvec);
909 632 : index = start;
910 763 : while (index < end && find_lock_entries(mapping, index, end - 1,
911 : &pvec, indices)) {
912 799 : for (i = 0; i < pagevec_count(&pvec); i++) {
913 668 : struct page *page = pvec.pages[i];
914 :
915 668 : index = indices[i];
916 :
917 668 : if (xa_is_value(page)) {
918 0 : if (unfalloc)
919 0 : continue;
920 0 : nr_swaps_freed += !shmem_free_swap(mapping,
921 : index, page);
922 0 : continue;
923 : }
924 668 : index += thp_nr_pages(page) - 1;
925 :
926 668 : if (!unfalloc || !PageUptodate(page))
927 668 : truncate_inode_page(mapping, page);
928 668 : unlock_page(page);
929 : }
930 131 : pagevec_remove_exceptionals(&pvec);
931 131 : pagevec_release(&pvec);
932 131 : cond_resched();
933 131 : index++;
934 : }
935 :
936 632 : if (partial_start) {
937 2 : struct page *page = NULL;
938 2 : shmem_getpage(inode, start - 1, &page, SGP_READ);
939 2 : if (page) {
940 2 : unsigned int top = PAGE_SIZE;
941 2 : if (start > end) {
942 0 : top = partial_end;
943 0 : partial_end = 0;
944 : }
945 2 : zero_user_segment(page, partial_start, top);
946 2 : set_page_dirty(page);
947 2 : unlock_page(page);
948 2 : put_page(page);
949 : }
950 : }
951 632 : if (partial_end) {
952 0 : struct page *page = NULL;
953 0 : shmem_getpage(inode, end, &page, SGP_READ);
954 0 : if (page) {
955 0 : zero_user_segment(page, 0, partial_end);
956 0 : set_page_dirty(page);
957 0 : unlock_page(page);
958 0 : put_page(page);
959 : }
960 : }
961 632 : if (start >= end)
962 0 : return;
963 :
964 : index = start;
965 632 : while (index < end) {
966 632 : cond_resched();
967 :
968 632 : if (!find_get_entries(mapping, index, end - 1, &pvec,
969 : indices)) {
970 : /* If all gone or hole-punch or unfalloc, we're done */
971 632 : if (index == start || end != -1)
972 : break;
973 : /* But if truncating, restart to make sure all gone */
974 0 : index = start;
975 0 : continue;
976 : }
977 0 : for (i = 0; i < pagevec_count(&pvec); i++) {
978 0 : struct page *page = pvec.pages[i];
979 :
980 0 : index = indices[i];
981 0 : if (xa_is_value(page)) {
982 0 : if (unfalloc)
983 0 : continue;
984 0 : if (shmem_free_swap(mapping, index, page)) {
985 : /* Swap was replaced by page: retry */
986 0 : index--;
987 0 : break;
988 : }
989 0 : nr_swaps_freed++;
990 0 : continue;
991 : }
992 :
993 0 : lock_page(page);
994 :
995 0 : if (!unfalloc || !PageUptodate(page)) {
996 0 : if (page_mapping(page) != mapping) {
997 : /* Page was replaced by swap: retry */
998 0 : unlock_page(page);
999 0 : index--;
1000 0 : break;
1001 : }
1002 0 : VM_BUG_ON_PAGE(PageWriteback(page), page);
1003 0 : if (shmem_punch_compound(page, start, end))
1004 0 : truncate_inode_page(mapping, page);
1005 0 : else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
1006 : /* Wipe the page and don't get stuck */
1007 0 : clear_highpage(page);
1008 0 : flush_dcache_page(page);
1009 0 : set_page_dirty(page);
1010 0 : if (index <
1011 0 : round_up(start, HPAGE_PMD_NR))
1012 0 : start = index + 1;
1013 : }
1014 : }
1015 0 : unlock_page(page);
1016 : }
1017 0 : pagevec_remove_exceptionals(&pvec);
1018 0 : pagevec_release(&pvec);
1019 0 : index++;
1020 : }
1021 :
1022 632 : spin_lock_irq(&info->lock);
1023 632 : info->swapped -= nr_swaps_freed;
1024 632 : shmem_recalc_inode(inode);
1025 632 : spin_unlock_irq(&info->lock);
1026 : }
1027 :
1028 632 : void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
1029 : {
1030 632 : shmem_undo_range(inode, lstart, lend, false);
1031 632 : inode->i_ctime = inode->i_mtime = current_time(inode);
1032 632 : }
1033 : EXPORT_SYMBOL_GPL(shmem_truncate_range);
1034 :
1035 521 : static int shmem_getattr(struct user_namespace *mnt_userns,
1036 : const struct path *path, struct kstat *stat,
1037 : u32 request_mask, unsigned int query_flags)
1038 : {
1039 521 : struct inode *inode = path->dentry->d_inode;
1040 521 : struct shmem_inode_info *info = SHMEM_I(inode);
1041 521 : struct shmem_sb_info *sb_info = SHMEM_SB(inode->i_sb);
1042 :
1043 521 : if (info->alloced - info->swapped != inode->i_mapping->nrpages) {
1044 0 : spin_lock_irq(&info->lock);
1045 0 : shmem_recalc_inode(inode);
1046 0 : spin_unlock_irq(&info->lock);
1047 : }
1048 521 : generic_fillattr(&init_user_ns, inode, stat);
1049 :
1050 521 : if (is_huge_enabled(sb_info))
1051 0 : stat->blksize = HPAGE_PMD_SIZE;
1052 :
1053 521 : return 0;
1054 : }
1055 :
1056 271 : static int shmem_setattr(struct user_namespace *mnt_userns,
1057 : struct dentry *dentry, struct iattr *attr)
1058 : {
1059 271 : struct inode *inode = d_inode(dentry);
1060 271 : struct shmem_inode_info *info = SHMEM_I(inode);
1061 271 : struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1062 271 : int error;
1063 :
1064 271 : error = setattr_prepare(&init_user_ns, dentry, attr);
1065 271 : if (error)
1066 : return error;
1067 :
1068 271 : if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
1069 54 : loff_t oldsize = inode->i_size;
1070 54 : loff_t newsize = attr->ia_size;
1071 :
1072 : /* protected by i_mutex */
1073 54 : if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
1074 0 : (newsize > oldsize && (info->seals & F_SEAL_GROW)))
1075 : return -EPERM;
1076 :
1077 54 : if (newsize != oldsize) {
1078 2 : error = shmem_reacct_size(SHMEM_I(inode)->flags,
1079 : oldsize, newsize);
1080 2 : if (error)
1081 : return error;
1082 2 : i_size_write(inode, newsize);
1083 2 : inode->i_ctime = inode->i_mtime = current_time(inode);
1084 : }
1085 54 : if (newsize <= oldsize) {
1086 54 : loff_t holebegin = round_up(newsize, PAGE_SIZE);
1087 54 : if (oldsize > holebegin)
1088 2 : unmap_mapping_range(inode->i_mapping,
1089 : holebegin, 0, 1);
1090 54 : if (info->alloced)
1091 46 : shmem_truncate_range(inode,
1092 : newsize, (loff_t)-1);
1093 : /* unmap again to remove racily COWed private pages */
1094 54 : if (oldsize > holebegin)
1095 2 : unmap_mapping_range(inode->i_mapping,
1096 : holebegin, 0, 1);
1097 :
1098 : /*
1099 : * Part of the huge page can be beyond i_size: subject
1100 : * to shrink under memory pressure.
1101 : */
1102 54 : if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
1103 54 : spin_lock(&sbinfo->shrinklist_lock);
1104 : /*
1105 : * _careful to defend against unlocked access to
1106 : * ->shrink_list in shmem_unused_huge_shrink()
1107 : */
1108 54 : if (list_empty_careful(&info->shrinklist)) {
1109 10 : list_add_tail(&info->shrinklist,
1110 : &sbinfo->shrinklist);
1111 10 : sbinfo->shrinklist_len++;
1112 : }
1113 54 : spin_unlock(&sbinfo->shrinklist_lock);
1114 : }
1115 : }
1116 : }
1117 :
1118 271 : setattr_copy(&init_user_ns, inode, attr);
1119 271 : if (attr->ia_valid & ATTR_MODE)
1120 271 : error = posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
1121 : return error;
1122 : }
1123 :
1124 1162 : static void shmem_evict_inode(struct inode *inode)
1125 : {
1126 1162 : struct shmem_inode_info *info = SHMEM_I(inode);
1127 1162 : struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1128 :
1129 1162 : if (shmem_mapping(inode->i_mapping)) {
1130 586 : shmem_unacct_size(info->flags, inode->i_size);
1131 586 : inode->i_size = 0;
1132 586 : shmem_truncate_range(inode, 0, (loff_t)-1);
1133 586 : if (!list_empty(&info->shrinklist)) {
1134 6 : spin_lock(&sbinfo->shrinklist_lock);
1135 6 : if (!list_empty(&info->shrinklist)) {
1136 6 : list_del_init(&info->shrinklist);
1137 6 : sbinfo->shrinklist_len--;
1138 : }
1139 6 : spin_unlock(&sbinfo->shrinklist_lock);
1140 : }
1141 586 : while (!list_empty(&info->swaplist)) {
1142 : /* Wait while shmem_unuse() is scanning this inode... */
1143 0 : wait_var_event(&info->stop_eviction,
1144 : !atomic_read(&info->stop_eviction));
1145 0 : mutex_lock(&shmem_swaplist_mutex);
1146 : /* ...but beware of the race if we peeked too early */
1147 0 : if (!atomic_read(&info->stop_eviction))
1148 0 : list_del_init(&info->swaplist);
1149 0 : mutex_unlock(&shmem_swaplist_mutex);
1150 : }
1151 : }
1152 :
1153 1162 : simple_xattrs_free(&info->xattrs);
1154 1162 : WARN_ON(inode->i_blocks);
1155 1162 : shmem_free_inode(inode->i_sb);
1156 1162 : clear_inode(inode);
1157 1162 : }
1158 :
1159 : extern struct swap_info_struct *swap_info[];
1160 :
1161 0 : static int shmem_find_swap_entries(struct address_space *mapping,
1162 : pgoff_t start, unsigned int nr_entries,
1163 : struct page **entries, pgoff_t *indices,
1164 : unsigned int type, bool frontswap)
1165 : {
1166 0 : XA_STATE(xas, &mapping->i_pages, start);
1167 0 : struct page *page;
1168 0 : swp_entry_t entry;
1169 0 : unsigned int ret = 0;
1170 :
1171 0 : if (!nr_entries)
1172 : return 0;
1173 :
1174 0 : rcu_read_lock();
1175 0 : xas_for_each(&xas, page, ULONG_MAX) {
1176 0 : if (xas_retry(&xas, page))
1177 0 : continue;
1178 :
1179 0 : if (!xa_is_value(page))
1180 0 : continue;
1181 :
1182 0 : entry = radix_to_swp_entry(page);
1183 0 : if (swp_type(entry) != type)
1184 0 : continue;
1185 0 : if (frontswap &&
1186 0 : !frontswap_test(swap_info[type], swp_offset(entry)))
1187 0 : continue;
1188 :
1189 0 : indices[ret] = xas.xa_index;
1190 0 : entries[ret] = page;
1191 :
1192 0 : if (need_resched()) {
1193 0 : xas_pause(&xas);
1194 0 : cond_resched_rcu();
1195 : }
1196 0 : if (++ret == nr_entries)
1197 : break;
1198 : }
1199 0 : rcu_read_unlock();
1200 :
1201 0 : return ret;
1202 : }
1203 :
1204 : /*
1205 : * Move the swapped pages for an inode to page cache. Returns the count
1206 : * of pages swapped in, or the error in case of failure.
1207 : */
1208 0 : static int shmem_unuse_swap_entries(struct inode *inode, struct pagevec pvec,
1209 : pgoff_t *indices)
1210 : {
1211 0 : int i = 0;
1212 0 : int ret = 0;
1213 0 : int error = 0;
1214 0 : struct address_space *mapping = inode->i_mapping;
1215 :
1216 0 : for (i = 0; i < pvec.nr; i++) {
1217 0 : struct page *page = pvec.pages[i];
1218 :
1219 0 : if (!xa_is_value(page))
1220 0 : continue;
1221 0 : error = shmem_swapin_page(inode, indices[i],
1222 : &page, SGP_CACHE,
1223 : mapping_gfp_mask(mapping),
1224 : NULL, NULL);
1225 0 : if (error == 0) {
1226 0 : unlock_page(page);
1227 0 : put_page(page);
1228 0 : ret++;
1229 : }
1230 0 : if (error == -ENOMEM)
1231 : break;
1232 0 : error = 0;
1233 : }
1234 0 : return error ? error : ret;
1235 : }
1236 :
1237 : /*
1238 : * If swap found in inode, free it and move page from swapcache to filecache.
1239 : */
1240 0 : static int shmem_unuse_inode(struct inode *inode, unsigned int type,
1241 : bool frontswap, unsigned long *fs_pages_to_unuse)
1242 : {
1243 0 : struct address_space *mapping = inode->i_mapping;
1244 0 : pgoff_t start = 0;
1245 0 : struct pagevec pvec;
1246 0 : pgoff_t indices[PAGEVEC_SIZE];
1247 0 : bool frontswap_partial = (frontswap && *fs_pages_to_unuse > 0);
1248 0 : int ret = 0;
1249 :
1250 0 : pagevec_init(&pvec);
1251 0 : do {
1252 0 : unsigned int nr_entries = PAGEVEC_SIZE;
1253 :
1254 0 : if (frontswap_partial && *fs_pages_to_unuse < PAGEVEC_SIZE)
1255 0 : nr_entries = *fs_pages_to_unuse;
1256 :
1257 0 : pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries,
1258 : pvec.pages, indices,
1259 : type, frontswap);
1260 0 : if (pvec.nr == 0) {
1261 : ret = 0;
1262 : break;
1263 : }
1264 :
1265 0 : ret = shmem_unuse_swap_entries(inode, pvec, indices);
1266 0 : if (ret < 0)
1267 : break;
1268 :
1269 0 : if (frontswap_partial) {
1270 0 : *fs_pages_to_unuse -= ret;
1271 0 : if (*fs_pages_to_unuse == 0) {
1272 : ret = FRONTSWAP_PAGES_UNUSED;
1273 : break;
1274 : }
1275 : }
1276 :
1277 0 : start = indices[pvec.nr - 1];
1278 0 : } while (true);
1279 :
1280 0 : return ret;
1281 : }
1282 :
1283 : /*
1284 : * Read all the shared memory data that resides in the swap
1285 : * device 'type' back into memory, so the swap device can be
1286 : * unused.
1287 : */
1288 0 : int shmem_unuse(unsigned int type, bool frontswap,
1289 : unsigned long *fs_pages_to_unuse)
1290 : {
1291 0 : struct shmem_inode_info *info, *next;
1292 0 : int error = 0;
1293 :
1294 0 : if (list_empty(&shmem_swaplist))
1295 : return 0;
1296 :
1297 0 : mutex_lock(&shmem_swaplist_mutex);
1298 0 : list_for_each_entry_safe(info, next, &shmem_swaplist, swaplist) {
1299 0 : if (!info->swapped) {
1300 0 : list_del_init(&info->swaplist);
1301 0 : continue;
1302 : }
1303 : /*
1304 : * Drop the swaplist mutex while searching the inode for swap;
1305 : * but before doing so, make sure shmem_evict_inode() will not
1306 : * remove placeholder inode from swaplist, nor let it be freed
1307 : * (igrab() would protect from unlink, but not from unmount).
1308 : */
1309 0 : atomic_inc(&info->stop_eviction);
1310 0 : mutex_unlock(&shmem_swaplist_mutex);
1311 :
1312 0 : error = shmem_unuse_inode(&info->vfs_inode, type, frontswap,
1313 : fs_pages_to_unuse);
1314 0 : cond_resched();
1315 :
1316 0 : mutex_lock(&shmem_swaplist_mutex);
1317 0 : next = list_next_entry(info, swaplist);
1318 0 : if (!info->swapped)
1319 0 : list_del_init(&info->swaplist);
1320 0 : if (atomic_dec_and_test(&info->stop_eviction))
1321 0 : wake_up_var(&info->stop_eviction);
1322 0 : if (error)
1323 : break;
1324 : }
1325 0 : mutex_unlock(&shmem_swaplist_mutex);
1326 :
1327 0 : return error;
1328 : }
1329 :
1330 : /*
1331 : * Move the page from the page cache to the swap cache.
1332 : */
1333 0 : static int shmem_writepage(struct page *page, struct writeback_control *wbc)
1334 : {
1335 0 : struct shmem_inode_info *info;
1336 0 : struct address_space *mapping;
1337 0 : struct inode *inode;
1338 0 : swp_entry_t swap;
1339 0 : pgoff_t index;
1340 :
1341 0 : VM_BUG_ON_PAGE(PageCompound(page), page);
1342 0 : BUG_ON(!PageLocked(page));
1343 0 : mapping = page->mapping;
1344 0 : index = page->index;
1345 0 : inode = mapping->host;
1346 0 : info = SHMEM_I(inode);
1347 0 : if (info->flags & VM_LOCKED)
1348 : goto redirty;
1349 0 : if (!total_swap_pages)
1350 0 : goto redirty;
1351 :
1352 : /*
1353 : * Our capabilities prevent regular writeback or sync from ever calling
1354 : * shmem_writepage; but a stacking filesystem might use ->writepage of
1355 : * its underlying filesystem, in which case tmpfs should write out to
1356 : * swap only in response to memory pressure, and not for the writeback
1357 : * threads or sync.
1358 : */
1359 : if (!wbc->for_reclaim) {
1360 : WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
1361 : goto redirty;
1362 : }
1363 :
1364 : /*
1365 : * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
1366 : * value into swapfile.c, the only way we can correctly account for a
1367 : * fallocated page arriving here is now to initialize it and write it.
1368 : *
1369 : * That's okay for a page already fallocated earlier, but if we have
1370 : * not yet completed the fallocation, then (a) we want to keep track
1371 : * of this page in case we have to undo it, and (b) it may not be a
1372 : * good idea to continue anyway, once we're pushing into swap. So
1373 : * reactivate the page, and let shmem_fallocate() quit when too many.
1374 : */
1375 : if (!PageUptodate(page)) {
1376 : if (inode->i_private) {
1377 : struct shmem_falloc *shmem_falloc;
1378 : spin_lock(&inode->i_lock);
1379 : shmem_falloc = inode->i_private;
1380 : if (shmem_falloc &&
1381 : !shmem_falloc->waitq &&
1382 : index >= shmem_falloc->start &&
1383 : index < shmem_falloc->next)
1384 : shmem_falloc->nr_unswapped++;
1385 : else
1386 : shmem_falloc = NULL;
1387 : spin_unlock(&inode->i_lock);
1388 : if (shmem_falloc)
1389 : goto redirty;
1390 : }
1391 : clear_highpage(page);
1392 : flush_dcache_page(page);
1393 : SetPageUptodate(page);
1394 : }
1395 :
1396 : swap = get_swap_page(page);
1397 : if (!swap.val)
1398 : goto redirty;
1399 :
1400 : /*
1401 : * Add inode to shmem_unuse()'s list of swapped-out inodes,
1402 : * if it's not already there. Do it now before the page is
1403 : * moved to swap cache, when its pagelock no longer protects
1404 : * the inode from eviction. But don't unlock the mutex until
1405 : * we've incremented swapped, because shmem_unuse_inode() will
1406 : * prune a !swapped inode from the swaplist under this mutex.
1407 : */
1408 : mutex_lock(&shmem_swaplist_mutex);
1409 : if (list_empty(&info->swaplist))
1410 : list_add(&info->swaplist, &shmem_swaplist);
1411 :
1412 : if (add_to_swap_cache(page, swap,
1413 : __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN,
1414 : NULL) == 0) {
1415 : spin_lock_irq(&info->lock);
1416 : shmem_recalc_inode(inode);
1417 : info->swapped++;
1418 : spin_unlock_irq(&info->lock);
1419 :
1420 : swap_shmem_alloc(swap);
1421 : shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
1422 :
1423 : mutex_unlock(&shmem_swaplist_mutex);
1424 : BUG_ON(page_mapped(page));
1425 : swap_writepage(page, wbc);
1426 : return 0;
1427 : }
1428 :
1429 : mutex_unlock(&shmem_swaplist_mutex);
1430 : put_swap_page(page, swap);
1431 0 : redirty:
1432 0 : set_page_dirty(page);
1433 0 : if (wbc->for_reclaim)
1434 : return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
1435 0 : unlock_page(page);
1436 0 : return 0;
1437 : }
1438 :
1439 : #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
1440 1915 : static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
1441 : {
1442 1915 : char buffer[64];
1443 :
1444 1915 : if (!mpol || mpol->mode == MPOL_DEFAULT)
1445 1915 : return; /* show nothing */
1446 :
1447 0 : mpol_to_str(buffer, sizeof(buffer), mpol);
1448 :
1449 0 : seq_printf(seq, ",mpol=%s", buffer);
1450 : }
1451 :
1452 757 : static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1453 : {
1454 757 : struct mempolicy *mpol = NULL;
1455 757 : if (sbinfo->mpol) {
1456 0 : spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */
1457 0 : mpol = sbinfo->mpol;
1458 0 : mpol_get(mpol);
1459 0 : spin_unlock(&sbinfo->stat_lock);
1460 : }
1461 757 : return mpol;
1462 : }
1463 : #else /* !CONFIG_NUMA || !CONFIG_TMPFS */
1464 : static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
1465 : {
1466 : }
1467 : static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1468 : {
1469 : return NULL;
1470 : }
1471 : #endif /* CONFIG_NUMA && CONFIG_TMPFS */
1472 : #ifndef CONFIG_NUMA
1473 : #define vm_policy vm_private_data
1474 : #endif
1475 :
1476 1985 : static void shmem_pseudo_vma_init(struct vm_area_struct *vma,
1477 : struct shmem_inode_info *info, pgoff_t index)
1478 : {
1479 : /* Create a pseudo vma that just contains the policy */
1480 1985 : vma_init(vma, NULL);
1481 : /* Bias interleave by inode number to distribute better across nodes */
1482 1985 : vma->vm_pgoff = index + info->vfs_inode.i_ino;
1483 1985 : vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index);
1484 1985 : }
1485 :
1486 1985 : static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma)
1487 : {
1488 : /* Drop reference taken by mpol_shared_policy_lookup() */
1489 1985 : mpol_cond_put(vma->vm_policy);
1490 : }
1491 :
1492 0 : static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
1493 : struct shmem_inode_info *info, pgoff_t index)
1494 : {
1495 0 : struct vm_area_struct pvma;
1496 0 : struct page *page;
1497 0 : struct vm_fault vmf = {
1498 : .vma = &pvma,
1499 : };
1500 :
1501 0 : shmem_pseudo_vma_init(&pvma, info, index);
1502 0 : page = swap_cluster_readahead(swap, gfp, &vmf);
1503 0 : shmem_pseudo_vma_destroy(&pvma);
1504 :
1505 0 : return page;
1506 : }
1507 :
1508 : /*
1509 : * Make sure huge_gfp is always more limited than limit_gfp.
1510 : * Some of the flags set permissions, while others set limitations.
1511 : */
1512 0 : static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp)
1513 : {
1514 0 : gfp_t allowflags = __GFP_IO | __GFP_FS | __GFP_RECLAIM;
1515 0 : gfp_t denyflags = __GFP_NOWARN | __GFP_NORETRY;
1516 0 : gfp_t zoneflags = limit_gfp & GFP_ZONEMASK;
1517 0 : gfp_t result = huge_gfp & ~(allowflags | GFP_ZONEMASK);
1518 :
1519 : /* Allow allocations only from the originally specified zones. */
1520 0 : result |= zoneflags;
1521 :
1522 : /*
1523 : * Minimize the result gfp by taking the union with the deny flags,
1524 : * and the intersection of the allow flags.
1525 : */
1526 0 : result |= (limit_gfp & denyflags);
1527 0 : result |= (huge_gfp & limit_gfp) & allowflags;
1528 :
1529 0 : return result;
1530 : }
1531 :
1532 0 : static struct page *shmem_alloc_hugepage(gfp_t gfp,
1533 : struct shmem_inode_info *info, pgoff_t index)
1534 : {
1535 0 : struct vm_area_struct pvma;
1536 0 : struct address_space *mapping = info->vfs_inode.i_mapping;
1537 0 : pgoff_t hindex;
1538 0 : struct page *page;
1539 :
1540 0 : hindex = round_down(index, HPAGE_PMD_NR);
1541 0 : if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1,
1542 : XA_PRESENT))
1543 : return NULL;
1544 :
1545 0 : shmem_pseudo_vma_init(&pvma, info, hindex);
1546 0 : page = alloc_pages_vma(gfp, HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(),
1547 : true);
1548 0 : shmem_pseudo_vma_destroy(&pvma);
1549 0 : if (page)
1550 0 : prep_transhuge_page(page);
1551 : else
1552 0 : count_vm_event(THP_FILE_FALLBACK);
1553 : return page;
1554 : }
1555 :
1556 1985 : static struct page *shmem_alloc_page(gfp_t gfp,
1557 : struct shmem_inode_info *info, pgoff_t index)
1558 : {
1559 1985 : struct vm_area_struct pvma;
1560 1985 : struct page *page;
1561 :
1562 1985 : shmem_pseudo_vma_init(&pvma, info, index);
1563 1985 : page = alloc_page_vma(gfp, &pvma, 0);
1564 1985 : shmem_pseudo_vma_destroy(&pvma);
1565 :
1566 1985 : return page;
1567 : }
1568 :
1569 1985 : static struct page *shmem_alloc_and_acct_page(gfp_t gfp,
1570 : struct inode *inode,
1571 : pgoff_t index, bool huge)
1572 : {
1573 1985 : struct shmem_inode_info *info = SHMEM_I(inode);
1574 1985 : struct page *page;
1575 1985 : int nr;
1576 1985 : int err = -ENOSPC;
1577 :
1578 1985 : if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
1579 : huge = false;
1580 1985 : nr = huge ? HPAGE_PMD_NR : 1;
1581 :
1582 1985 : if (!shmem_inode_acct_block(inode, nr))
1583 0 : goto failed;
1584 :
1585 1985 : if (huge)
1586 0 : page = shmem_alloc_hugepage(gfp, info, index);
1587 : else
1588 1985 : page = shmem_alloc_page(gfp, info, index);
1589 1985 : if (page) {
1590 1985 : __SetPageLocked(page);
1591 1985 : __SetPageSwapBacked(page);
1592 1985 : return page;
1593 : }
1594 :
1595 0 : err = -ENOMEM;
1596 0 : shmem_inode_unacct_blocks(inode, nr);
1597 0 : failed:
1598 0 : return ERR_PTR(err);
1599 : }
1600 :
1601 : /*
1602 : * When a page is moved from swapcache to shmem filecache (either by the
1603 : * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
1604 : * shmem_unuse_inode()), it may have been read in earlier from swap, in
1605 : * ignorance of the mapping it belongs to. If that mapping has special
1606 : * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
1607 : * we may need to copy to a suitable page before moving to filecache.
1608 : *
1609 : * In a future release, this may well be extended to respect cpuset and
1610 : * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
1611 : * but for now it is a simple matter of zone.
1612 : */
1613 : static bool shmem_should_replace_page(struct page *page, gfp_t gfp)
1614 : {
1615 : return page_zonenum(page) > gfp_zone(gfp);
1616 : }
1617 :
1618 : static int shmem_replace_page(struct page **pagep, gfp_t gfp,
1619 : struct shmem_inode_info *info, pgoff_t index)
1620 : {
1621 : struct page *oldpage, *newpage;
1622 : struct address_space *swap_mapping;
1623 : swp_entry_t entry;
1624 : pgoff_t swap_index;
1625 : int error;
1626 :
1627 : oldpage = *pagep;
1628 : entry.val = page_private(oldpage);
1629 : swap_index = swp_offset(entry);
1630 : swap_mapping = page_mapping(oldpage);
1631 :
1632 : /*
1633 : * We have arrived here because our zones are constrained, so don't
1634 : * limit chance of success by further cpuset and node constraints.
1635 : */
1636 : gfp &= ~GFP_CONSTRAINT_MASK;
1637 : newpage = shmem_alloc_page(gfp, info, index);
1638 : if (!newpage)
1639 : return -ENOMEM;
1640 :
1641 : get_page(newpage);
1642 : copy_highpage(newpage, oldpage);
1643 : flush_dcache_page(newpage);
1644 :
1645 : __SetPageLocked(newpage);
1646 : __SetPageSwapBacked(newpage);
1647 : SetPageUptodate(newpage);
1648 : set_page_private(newpage, entry.val);
1649 : SetPageSwapCache(newpage);
1650 :
1651 : /*
1652 : * Our caller will very soon move newpage out of swapcache, but it's
1653 : * a nice clean interface for us to replace oldpage by newpage there.
1654 : */
1655 : xa_lock_irq(&swap_mapping->i_pages);
1656 : error = shmem_replace_entry(swap_mapping, swap_index, oldpage, newpage);
1657 : if (!error) {
1658 : mem_cgroup_migrate(oldpage, newpage);
1659 : __inc_lruvec_page_state(newpage, NR_FILE_PAGES);
1660 : __dec_lruvec_page_state(oldpage, NR_FILE_PAGES);
1661 : }
1662 : xa_unlock_irq(&swap_mapping->i_pages);
1663 :
1664 : if (unlikely(error)) {
1665 : /*
1666 : * Is this possible? I think not, now that our callers check
1667 : * both PageSwapCache and page_private after getting page lock;
1668 : * but be defensive. Reverse old to newpage for clear and free.
1669 : */
1670 : oldpage = newpage;
1671 : } else {
1672 : lru_cache_add(newpage);
1673 : *pagep = newpage;
1674 : }
1675 :
1676 : ClearPageSwapCache(oldpage);
1677 : set_page_private(oldpage, 0);
1678 :
1679 : unlock_page(oldpage);
1680 : put_page(oldpage);
1681 : put_page(oldpage);
1682 : return error;
1683 : }
1684 :
1685 : /*
1686 : * Swap in the page pointed to by *pagep.
1687 : * Caller has to make sure that *pagep contains a valid swapped page.
1688 : * Returns 0 and the page in pagep if success. On failure, returns the
1689 : * error code and NULL in *pagep.
1690 : */
1691 0 : static int shmem_swapin_page(struct inode *inode, pgoff_t index,
1692 : struct page **pagep, enum sgp_type sgp,
1693 : gfp_t gfp, struct vm_area_struct *vma,
1694 : vm_fault_t *fault_type)
1695 : {
1696 0 : struct address_space *mapping = inode->i_mapping;
1697 0 : struct shmem_inode_info *info = SHMEM_I(inode);
1698 0 : struct mm_struct *charge_mm = vma ? vma->vm_mm : current->mm;
1699 0 : struct page *page;
1700 0 : swp_entry_t swap;
1701 0 : int error;
1702 :
1703 0 : VM_BUG_ON(!*pagep || !xa_is_value(*pagep));
1704 0 : swap = radix_to_swp_entry(*pagep);
1705 0 : *pagep = NULL;
1706 :
1707 : /* Look it up and read it in.. */
1708 0 : page = lookup_swap_cache(swap, NULL, 0);
1709 0 : if (!page) {
1710 : /* Or update major stats only when swapin succeeds?? */
1711 0 : if (fault_type) {
1712 0 : *fault_type |= VM_FAULT_MAJOR;
1713 0 : count_vm_event(PGMAJFAULT);
1714 0 : count_memcg_event_mm(charge_mm, PGMAJFAULT);
1715 : }
1716 : /* Here we actually start the io */
1717 0 : page = shmem_swapin(swap, gfp, info, index);
1718 0 : if (!page) {
1719 0 : error = -ENOMEM;
1720 0 : goto failed;
1721 : }
1722 : }
1723 :
1724 : /* We have to do this with page locked to prevent races */
1725 0 : lock_page(page);
1726 0 : if (!PageSwapCache(page) || page_private(page) != swap.val ||
1727 : !shmem_confirm_swap(mapping, index, swap)) {
1728 0 : error = -EEXIST;
1729 0 : goto unlock;
1730 : }
1731 : if (!PageUptodate(page)) {
1732 : error = -EIO;
1733 : goto failed;
1734 : }
1735 : wait_on_page_writeback(page);
1736 :
1737 : /*
1738 : * Some architectures may have to restore extra metadata to the
1739 : * physical page after reading from swap.
1740 : */
1741 : arch_swap_restore(swap, page);
1742 :
1743 : if (shmem_should_replace_page(page, gfp)) {
1744 : error = shmem_replace_page(&page, gfp, info, index);
1745 : if (error)
1746 : goto failed;
1747 : }
1748 :
1749 : error = shmem_add_to_page_cache(page, mapping, index,
1750 : swp_to_radix_entry(swap), gfp,
1751 : charge_mm);
1752 : if (error)
1753 : goto failed;
1754 :
1755 : spin_lock_irq(&info->lock);
1756 : info->swapped--;
1757 : shmem_recalc_inode(inode);
1758 : spin_unlock_irq(&info->lock);
1759 :
1760 : if (sgp == SGP_WRITE)
1761 : mark_page_accessed(page);
1762 :
1763 : delete_from_swap_cache(page);
1764 : set_page_dirty(page);
1765 : swap_free(swap);
1766 :
1767 : *pagep = page;
1768 : return 0;
1769 0 : failed:
1770 0 : if (!shmem_confirm_swap(mapping, index, swap))
1771 0 : error = -EEXIST;
1772 0 : unlock:
1773 0 : if (page) {
1774 0 : unlock_page(page);
1775 0 : put_page(page);
1776 : }
1777 :
1778 0 : return error;
1779 : }
1780 :
1781 : /*
1782 : * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
1783 : *
1784 : * If we allocate a new one we do not mark it dirty. That's up to the
1785 : * vm. If we swap it in we mark it dirty since we also free the swap
1786 : * entry since a page cannot live in both the swap and page cache.
1787 : *
1788 : * vmf and fault_type are only supplied by shmem_fault:
1789 : * otherwise they are NULL.
1790 : */
1791 2338 : static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
1792 : struct page **pagep, enum sgp_type sgp, gfp_t gfp,
1793 : struct vm_area_struct *vma, struct vm_fault *vmf,
1794 : vm_fault_t *fault_type)
1795 : {
1796 2338 : struct address_space *mapping = inode->i_mapping;
1797 2338 : struct shmem_inode_info *info = SHMEM_I(inode);
1798 2338 : struct shmem_sb_info *sbinfo;
1799 2338 : struct mm_struct *charge_mm;
1800 2338 : struct page *page;
1801 2338 : enum sgp_type sgp_huge = sgp;
1802 2338 : pgoff_t hindex = index;
1803 2338 : gfp_t huge_gfp;
1804 2338 : int error;
1805 2338 : int once = 0;
1806 2338 : int alloced = 0;
1807 :
1808 2338 : if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
1809 : return -EFBIG;
1810 2338 : if (sgp == SGP_NOHUGE || sgp == SGP_HUGE)
1811 0 : sgp = SGP_CACHE;
1812 2338 : repeat:
1813 2338 : if (sgp <= SGP_CACHE &&
1814 352 : ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
1815 : return -EINVAL;
1816 : }
1817 :
1818 2338 : sbinfo = SHMEM_SB(inode->i_sb);
1819 2338 : charge_mm = vma ? vma->vm_mm : current->mm;
1820 :
1821 2338 : page = pagecache_get_page(mapping, index,
1822 : FGP_ENTRY | FGP_HEAD | FGP_LOCK, 0);
1823 2338 : if (xa_is_value(page)) {
1824 0 : error = shmem_swapin_page(inode, index, &page,
1825 : sgp, gfp, vma, fault_type);
1826 0 : if (error == -EEXIST)
1827 0 : goto repeat;
1828 :
1829 0 : *pagep = page;
1830 0 : return error;
1831 : }
1832 :
1833 2338 : if (page)
1834 353 : hindex = page->index;
1835 2338 : if (page && sgp == SGP_WRITE)
1836 3 : mark_page_accessed(page);
1837 :
1838 : /* fallocated page? */
1839 2338 : if (page && !PageUptodate(page)) {
1840 150 : if (sgp != SGP_READ)
1841 150 : goto clear;
1842 0 : unlock_page(page);
1843 0 : put_page(page);
1844 0 : page = NULL;
1845 0 : hindex = index;
1846 : }
1847 2188 : if (page || sgp == SGP_READ)
1848 203 : goto out;
1849 :
1850 : /*
1851 : * Fast cache lookup did not find it:
1852 : * bring it back from swap or allocate.
1853 : */
1854 :
1855 1985 : if (vma && userfaultfd_missing(vma)) {
1856 : *fault_type = handle_userfault(vmf, VM_UFFD_MISSING);
1857 : return 0;
1858 : }
1859 :
1860 : /* shmem_symlink() */
1861 1985 : if (!shmem_mapping(mapping))
1862 0 : goto alloc_nohuge;
1863 1985 : if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE)
1864 0 : goto alloc_nohuge;
1865 1985 : if (shmem_huge == SHMEM_HUGE_FORCE)
1866 0 : goto alloc_huge;
1867 1985 : switch (sbinfo->huge) {
1868 1985 : case SHMEM_HUGE_NEVER:
1869 1985 : goto alloc_nohuge;
1870 0 : case SHMEM_HUGE_WITHIN_SIZE: {
1871 0 : loff_t i_size;
1872 0 : pgoff_t off;
1873 :
1874 0 : off = round_up(index, HPAGE_PMD_NR);
1875 0 : i_size = round_up(i_size_read(inode), PAGE_SIZE);
1876 0 : if (i_size >= HPAGE_PMD_SIZE &&
1877 0 : i_size >> PAGE_SHIFT >= off)
1878 0 : goto alloc_huge;
1879 :
1880 0 : fallthrough;
1881 : }
1882 : case SHMEM_HUGE_ADVISE:
1883 0 : if (sgp_huge == SGP_HUGE)
1884 0 : goto alloc_huge;
1885 : /* TODO: implement fadvise() hints */
1886 0 : goto alloc_nohuge;
1887 : }
1888 :
1889 0 : alloc_huge:
1890 0 : huge_gfp = vma_thp_gfp_mask(vma);
1891 0 : huge_gfp = limit_gfp_mask(huge_gfp, gfp);
1892 0 : page = shmem_alloc_and_acct_page(huge_gfp, inode, index, true);
1893 0 : if (IS_ERR(page)) {
1894 0 : alloc_nohuge:
1895 1985 : page = shmem_alloc_and_acct_page(gfp, inode,
1896 : index, false);
1897 : }
1898 1985 : if (IS_ERR(page)) {
1899 0 : int retry = 5;
1900 :
1901 0 : error = PTR_ERR(page);
1902 0 : page = NULL;
1903 0 : if (error != -ENOSPC)
1904 0 : goto unlock;
1905 : /*
1906 : * Try to reclaim some space by splitting a huge page
1907 : * beyond i_size on the filesystem.
1908 : */
1909 0 : while (retry--) {
1910 0 : int ret;
1911 :
1912 0 : ret = shmem_unused_huge_shrink(sbinfo, NULL, 1);
1913 0 : if (ret == SHRINK_STOP)
1914 : break;
1915 0 : if (ret)
1916 0 : goto alloc_nohuge;
1917 : }
1918 0 : goto unlock;
1919 : }
1920 :
1921 1985 : if (PageTransHuge(page))
1922 0 : hindex = round_down(index, HPAGE_PMD_NR);
1923 : else
1924 : hindex = index;
1925 :
1926 1985 : if (sgp == SGP_WRITE)
1927 709 : __SetPageReferenced(page);
1928 :
1929 1985 : error = shmem_add_to_page_cache(page, mapping, hindex,
1930 : NULL, gfp & GFP_RECLAIM_MASK,
1931 : charge_mm);
1932 1985 : if (error)
1933 0 : goto unacct;
1934 1985 : lru_cache_add(page);
1935 :
1936 1985 : spin_lock_irq(&info->lock);
1937 1985 : info->alloced += compound_nr(page);
1938 1985 : inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page);
1939 1985 : shmem_recalc_inode(inode);
1940 1985 : spin_unlock_irq(&info->lock);
1941 1985 : alloced = true;
1942 :
1943 1985 : if (PageTransHuge(page) &&
1944 0 : DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) <
1945 0 : hindex + HPAGE_PMD_NR - 1) {
1946 : /*
1947 : * Part of the huge page is beyond i_size: subject
1948 : * to shrink under memory pressure.
1949 : */
1950 0 : spin_lock(&sbinfo->shrinklist_lock);
1951 : /*
1952 : * _careful to defend against unlocked access to
1953 : * ->shrink_list in shmem_unused_huge_shrink()
1954 : */
1955 0 : if (list_empty_careful(&info->shrinklist)) {
1956 0 : list_add_tail(&info->shrinklist,
1957 : &sbinfo->shrinklist);
1958 0 : sbinfo->shrinklist_len++;
1959 : }
1960 0 : spin_unlock(&sbinfo->shrinklist_lock);
1961 : }
1962 :
1963 : /*
1964 : * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
1965 : */
1966 1985 : if (sgp == SGP_FALLOC)
1967 1273 : sgp = SGP_WRITE;
1968 712 : clear:
1969 : /*
1970 : * Let SGP_WRITE caller clear ends if write does not fill page;
1971 : * but SGP_FALLOC on a page fallocated earlier must initialize
1972 : * it now, lest undo on failure cancel our earlier guarantee.
1973 : */
1974 2135 : if (sgp != SGP_WRITE && !PageUptodate(page)) {
1975 : int i;
1976 :
1977 306 : for (i = 0; i < compound_nr(page); i++) {
1978 153 : clear_highpage(page + i);
1979 153 : flush_dcache_page(page + i);
1980 : }
1981 153 : SetPageUptodate(page);
1982 : }
1983 :
1984 : /* Perhaps the file has been truncated since we checked */
1985 2135 : if (sgp <= SGP_CACHE &&
1986 153 : ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
1987 0 : if (alloced) {
1988 0 : ClearPageDirty(page);
1989 0 : delete_from_page_cache(page);
1990 0 : spin_lock_irq(&info->lock);
1991 0 : shmem_recalc_inode(inode);
1992 0 : spin_unlock_irq(&info->lock);
1993 : }
1994 0 : error = -EINVAL;
1995 0 : goto unlock;
1996 : }
1997 2135 : out:
1998 2338 : *pagep = page + index - hindex;
1999 2338 : return 0;
2000 :
2001 : /*
2002 : * Error recovery.
2003 : */
2004 0 : unacct:
2005 0 : shmem_inode_unacct_blocks(inode, compound_nr(page));
2006 :
2007 0 : if (PageTransHuge(page)) {
2008 0 : unlock_page(page);
2009 0 : put_page(page);
2010 0 : goto alloc_nohuge;
2011 : }
2012 0 : unlock:
2013 0 : if (page) {
2014 0 : unlock_page(page);
2015 0 : put_page(page);
2016 : }
2017 0 : if (error == -ENOSPC && !once++) {
2018 0 : spin_lock_irq(&info->lock);
2019 0 : shmem_recalc_inode(inode);
2020 0 : spin_unlock_irq(&info->lock);
2021 0 : goto repeat;
2022 : }
2023 0 : if (error == -EEXIST)
2024 0 : goto repeat;
2025 : return error;
2026 : }
2027 :
2028 : /*
2029 : * This is like autoremove_wake_function, but it removes the wait queue
2030 : * entry unconditionally - even if something else had already woken the
2031 : * target.
2032 : */
2033 0 : static int synchronous_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
2034 : {
2035 0 : int ret = default_wake_function(wait, mode, sync, key);
2036 0 : list_del_init(&wait->entry);
2037 0 : return ret;
2038 : }
2039 :
2040 163 : static vm_fault_t shmem_fault(struct vm_fault *vmf)
2041 : {
2042 163 : struct vm_area_struct *vma = vmf->vma;
2043 163 : struct inode *inode = file_inode(vma->vm_file);
2044 163 : gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
2045 163 : enum sgp_type sgp;
2046 163 : int err;
2047 163 : vm_fault_t ret = VM_FAULT_LOCKED;
2048 :
2049 : /*
2050 : * Trinity finds that probing a hole which tmpfs is punching can
2051 : * prevent the hole-punch from ever completing: which in turn
2052 : * locks writers out with its hold on i_mutex. So refrain from
2053 : * faulting pages into the hole while it's being punched. Although
2054 : * shmem_undo_range() does remove the additions, it may be unable to
2055 : * keep up, as each new page needs its own unmap_mapping_range() call,
2056 : * and the i_mmap tree grows ever slower to scan if new vmas are added.
2057 : *
2058 : * It does not matter if we sometimes reach this check just before the
2059 : * hole-punch begins, so that one fault then races with the punch:
2060 : * we just need to make racing faults a rare case.
2061 : *
2062 : * The implementation below would be much simpler if we just used a
2063 : * standard mutex or completion: but we cannot take i_mutex in fault,
2064 : * and bloating every shmem inode for this unlikely case would be sad.
2065 : */
2066 163 : if (unlikely(inode->i_private)) {
2067 0 : struct shmem_falloc *shmem_falloc;
2068 :
2069 0 : spin_lock(&inode->i_lock);
2070 0 : shmem_falloc = inode->i_private;
2071 0 : if (shmem_falloc &&
2072 0 : shmem_falloc->waitq &&
2073 0 : vmf->pgoff >= shmem_falloc->start &&
2074 0 : vmf->pgoff < shmem_falloc->next) {
2075 0 : struct file *fpin;
2076 0 : wait_queue_head_t *shmem_falloc_waitq;
2077 0 : DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function);
2078 :
2079 0 : ret = VM_FAULT_NOPAGE;
2080 0 : fpin = maybe_unlock_mmap_for_io(vmf, NULL);
2081 0 : if (fpin)
2082 0 : ret = VM_FAULT_RETRY;
2083 :
2084 0 : shmem_falloc_waitq = shmem_falloc->waitq;
2085 0 : prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait,
2086 : TASK_UNINTERRUPTIBLE);
2087 0 : spin_unlock(&inode->i_lock);
2088 0 : schedule();
2089 :
2090 : /*
2091 : * shmem_falloc_waitq points into the shmem_fallocate()
2092 : * stack of the hole-punching task: shmem_falloc_waitq
2093 : * is usually invalid by the time we reach here, but
2094 : * finish_wait() does not dereference it in that case;
2095 : * though i_lock needed lest racing with wake_up_all().
2096 : */
2097 0 : spin_lock(&inode->i_lock);
2098 0 : finish_wait(shmem_falloc_waitq, &shmem_fault_wait);
2099 0 : spin_unlock(&inode->i_lock);
2100 :
2101 0 : if (fpin)
2102 0 : fput(fpin);
2103 0 : return ret;
2104 : }
2105 0 : spin_unlock(&inode->i_lock);
2106 : }
2107 :
2108 163 : sgp = SGP_CACHE;
2109 :
2110 163 : if ((vma->vm_flags & VM_NOHUGEPAGE) ||
2111 163 : test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
2112 : sgp = SGP_NOHUGE;
2113 163 : else if (vma->vm_flags & VM_HUGEPAGE)
2114 0 : sgp = SGP_HUGE;
2115 :
2116 163 : err = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp,
2117 : gfp, vma, vmf, &ret);
2118 163 : if (err)
2119 0 : return vmf_error(err);
2120 163 : return ret;
2121 : }
2122 :
2123 14 : unsigned long shmem_get_unmapped_area(struct file *file,
2124 : unsigned long uaddr, unsigned long len,
2125 : unsigned long pgoff, unsigned long flags)
2126 : {
2127 14 : unsigned long (*get_area)(struct file *,
2128 : unsigned long, unsigned long, unsigned long, unsigned long);
2129 14 : unsigned long addr;
2130 14 : unsigned long offset;
2131 14 : unsigned long inflated_len;
2132 14 : unsigned long inflated_addr;
2133 14 : unsigned long inflated_offset;
2134 :
2135 14 : if (len > TASK_SIZE)
2136 : return -ENOMEM;
2137 :
2138 14 : get_area = current->mm->get_unmapped_area;
2139 14 : addr = get_area(file, uaddr, len, pgoff, flags);
2140 :
2141 14 : if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
2142 : return addr;
2143 14 : if (IS_ERR_VALUE(addr))
2144 : return addr;
2145 14 : if (addr & ~PAGE_MASK)
2146 : return addr;
2147 14 : if (addr > TASK_SIZE - len)
2148 : return addr;
2149 :
2150 14 : if (shmem_huge == SHMEM_HUGE_DENY)
2151 : return addr;
2152 14 : if (len < HPAGE_PMD_SIZE)
2153 : return addr;
2154 1 : if (flags & MAP_FIXED)
2155 : return addr;
2156 : /*
2157 : * Our priority is to support MAP_SHARED mapped hugely;
2158 : * and support MAP_PRIVATE mapped hugely too, until it is COWed.
2159 : * But if caller specified an address hint and we allocated area there
2160 : * successfully, respect that as before.
2161 : */
2162 1 : if (uaddr == addr)
2163 : return addr;
2164 :
2165 1 : if (shmem_huge != SHMEM_HUGE_FORCE) {
2166 1 : struct super_block *sb;
2167 :
2168 1 : if (file) {
2169 1 : VM_BUG_ON(file->f_op != &shmem_file_operations);
2170 1 : sb = file_inode(file)->i_sb;
2171 : } else {
2172 : /*
2173 : * Called directly from mm/mmap.c, or drivers/char/mem.c
2174 : * for "/dev/zero", to create a shared anonymous object.
2175 : */
2176 0 : if (IS_ERR(shm_mnt))
2177 : return addr;
2178 0 : sb = shm_mnt->mnt_sb;
2179 : }
2180 1 : if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER)
2181 : return addr;
2182 : }
2183 :
2184 0 : offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1);
2185 0 : if (offset && offset + len < 2 * HPAGE_PMD_SIZE)
2186 : return addr;
2187 0 : if ((addr & (HPAGE_PMD_SIZE-1)) == offset)
2188 : return addr;
2189 :
2190 0 : inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;
2191 0 : if (inflated_len > TASK_SIZE)
2192 : return addr;
2193 0 : if (inflated_len < len)
2194 : return addr;
2195 :
2196 0 : inflated_addr = get_area(NULL, uaddr, inflated_len, 0, flags);
2197 0 : if (IS_ERR_VALUE(inflated_addr))
2198 : return addr;
2199 0 : if (inflated_addr & ~PAGE_MASK)
2200 : return addr;
2201 :
2202 0 : inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
2203 0 : inflated_addr += offset - inflated_offset;
2204 0 : if (inflated_offset > offset)
2205 0 : inflated_addr += HPAGE_PMD_SIZE;
2206 :
2207 0 : if (inflated_addr > TASK_SIZE - len)
2208 0 : return addr;
2209 : return inflated_addr;
2210 : }
2211 :
2212 : #ifdef CONFIG_NUMA
2213 0 : static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
2214 : {
2215 0 : struct inode *inode = file_inode(vma->vm_file);
2216 0 : return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol);
2217 : }
2218 :
2219 8 : static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
2220 : unsigned long addr)
2221 : {
2222 8 : struct inode *inode = file_inode(vma->vm_file);
2223 8 : pgoff_t index;
2224 :
2225 8 : index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
2226 8 : return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index);
2227 : }
2228 : #endif
2229 :
2230 0 : int shmem_lock(struct file *file, int lock, struct user_struct *user)
2231 : {
2232 0 : struct inode *inode = file_inode(file);
2233 0 : struct shmem_inode_info *info = SHMEM_I(inode);
2234 0 : int retval = -ENOMEM;
2235 :
2236 : /*
2237 : * What serializes the accesses to info->flags?
2238 : * ipc_lock_object() when called from shmctl_do_lock(),
2239 : * no serialization needed when called from shm_destroy().
2240 : */
2241 0 : if (lock && !(info->flags & VM_LOCKED)) {
2242 0 : if (!user_shm_lock(inode->i_size, user))
2243 0 : goto out_nomem;
2244 0 : info->flags |= VM_LOCKED;
2245 0 : mapping_set_unevictable(file->f_mapping);
2246 : }
2247 0 : if (!lock && (info->flags & VM_LOCKED) && user) {
2248 0 : user_shm_unlock(inode->i_size, user);
2249 0 : info->flags &= ~VM_LOCKED;
2250 0 : mapping_clear_unevictable(file->f_mapping);
2251 : }
2252 : retval = 0;
2253 :
2254 0 : out_nomem:
2255 0 : return retval;
2256 : }
2257 :
2258 11 : static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
2259 : {
2260 11 : struct shmem_inode_info *info = SHMEM_I(file_inode(file));
2261 :
2262 11 : if (info->seals & F_SEAL_FUTURE_WRITE) {
2263 : /*
2264 : * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
2265 : * "future write" seal active.
2266 : */
2267 0 : if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
2268 : return -EPERM;
2269 :
2270 : /*
2271 : * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
2272 : * MAP_SHARED and read-only, take care to not allow mprotect to
2273 : * revert protections on such mappings. Do this only for shared
2274 : * mappings. For private mappings, don't need to mask
2275 : * VM_MAYWRITE as we still want them to be COW-writable.
2276 : */
2277 0 : if (vma->vm_flags & VM_SHARED)
2278 0 : vma->vm_flags &= ~(VM_MAYWRITE);
2279 : }
2280 :
2281 : /* arm64 - allow memory tagging on RAM-based files */
2282 11 : vma->vm_flags |= VM_MTE_ALLOWED;
2283 :
2284 11 : file_accessed(file);
2285 11 : vma->vm_ops = &shmem_vm_ops;
2286 11 : if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
2287 11 : ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
2288 11 : (vma->vm_end & HPAGE_PMD_MASK)) {
2289 1 : khugepaged_enter(vma, vma->vm_flags);
2290 : }
2291 : return 0;
2292 : }
2293 :
2294 1744 : static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir,
2295 : umode_t mode, dev_t dev, unsigned long flags)
2296 : {
2297 1744 : struct inode *inode;
2298 1744 : struct shmem_inode_info *info;
2299 1744 : struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
2300 1744 : ino_t ino;
2301 :
2302 1744 : if (shmem_reserve_inode(sb, &ino))
2303 : return NULL;
2304 :
2305 1744 : inode = new_inode(sb);
2306 1744 : if (inode) {
2307 1744 : inode->i_ino = ino;
2308 1744 : inode_init_owner(&init_user_ns, inode, dir, mode);
2309 1744 : inode->i_blocks = 0;
2310 1744 : inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
2311 1744 : inode->i_generation = prandom_u32();
2312 1744 : info = SHMEM_I(inode);
2313 1744 : memset(info, 0, (char *)inode - (char *)info);
2314 1744 : spin_lock_init(&info->lock);
2315 1744 : atomic_set(&info->stop_eviction, 0);
2316 1744 : info->seals = F_SEAL_SEAL;
2317 1744 : info->flags = flags & VM_NORESERVE;
2318 1744 : INIT_LIST_HEAD(&info->shrinklist);
2319 1744 : INIT_LIST_HEAD(&info->swaplist);
2320 1744 : simple_xattrs_init(&info->xattrs);
2321 1744 : cache_no_acl(inode);
2322 :
2323 1744 : switch (mode & S_IFMT) {
2324 166 : default:
2325 166 : inode->i_op = &shmem_special_inode_operations;
2326 166 : init_special_inode(inode, mode, dev);
2327 166 : break;
2328 757 : case S_IFREG:
2329 757 : inode->i_mapping->a_ops = &shmem_aops;
2330 757 : inode->i_op = &shmem_inode_operations;
2331 757 : inode->i_fop = &shmem_file_operations;
2332 757 : mpol_shared_policy_init(&info->policy,
2333 : shmem_get_sbmpol(sbinfo));
2334 757 : break;
2335 613 : case S_IFDIR:
2336 613 : inc_nlink(inode);
2337 : /* Some things misbehave if size == 0 on a directory */
2338 613 : inode->i_size = 2 * BOGO_DIRENT_SIZE;
2339 613 : inode->i_op = &shmem_dir_inode_operations;
2340 613 : inode->i_fop = &simple_dir_operations;
2341 613 : break;
2342 208 : case S_IFLNK:
2343 : /*
2344 : * Must not load anything in the rbtree,
2345 : * mpol_free_shared_policy will not be called.
2346 : */
2347 208 : mpol_shared_policy_init(&info->policy, NULL);
2348 208 : break;
2349 : }
2350 :
2351 1744 : lockdep_annotate_inode_mutex_key(inode);
2352 : } else
2353 0 : shmem_free_inode(sb);
2354 : return inode;
2355 : }
2356 :
2357 0 : static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
2358 : pmd_t *dst_pmd,
2359 : struct vm_area_struct *dst_vma,
2360 : unsigned long dst_addr,
2361 : unsigned long src_addr,
2362 : bool zeropage,
2363 : struct page **pagep)
2364 : {
2365 0 : struct inode *inode = file_inode(dst_vma->vm_file);
2366 0 : struct shmem_inode_info *info = SHMEM_I(inode);
2367 0 : struct address_space *mapping = inode->i_mapping;
2368 0 : gfp_t gfp = mapping_gfp_mask(mapping);
2369 0 : pgoff_t pgoff = linear_page_index(dst_vma, dst_addr);
2370 0 : spinlock_t *ptl;
2371 0 : void *page_kaddr;
2372 0 : struct page *page;
2373 0 : pte_t _dst_pte, *dst_pte;
2374 0 : int ret;
2375 0 : pgoff_t offset, max_off;
2376 :
2377 0 : ret = -ENOMEM;
2378 0 : if (!shmem_inode_acct_block(inode, 1))
2379 0 : goto out;
2380 :
2381 0 : if (!*pagep) {
2382 0 : page = shmem_alloc_page(gfp, info, pgoff);
2383 0 : if (!page)
2384 0 : goto out_unacct_blocks;
2385 :
2386 0 : if (!zeropage) { /* mcopy_atomic */
2387 0 : page_kaddr = kmap_atomic(page);
2388 0 : ret = copy_from_user(page_kaddr,
2389 : (const void __user *)src_addr,
2390 : PAGE_SIZE);
2391 0 : kunmap_atomic(page_kaddr);
2392 :
2393 : /* fallback to copy_from_user outside mmap_lock */
2394 0 : if (unlikely(ret)) {
2395 0 : *pagep = page;
2396 0 : shmem_inode_unacct_blocks(inode, 1);
2397 : /* don't free the page */
2398 0 : return -ENOENT;
2399 : }
2400 : } else { /* mfill_zeropage_atomic */
2401 0 : clear_highpage(page);
2402 : }
2403 : } else {
2404 0 : page = *pagep;
2405 0 : *pagep = NULL;
2406 : }
2407 :
2408 0 : VM_BUG_ON(PageLocked(page) || PageSwapBacked(page));
2409 0 : __SetPageLocked(page);
2410 0 : __SetPageSwapBacked(page);
2411 0 : __SetPageUptodate(page);
2412 :
2413 0 : ret = -EFAULT;
2414 0 : offset = linear_page_index(dst_vma, dst_addr);
2415 0 : max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
2416 0 : if (unlikely(offset >= max_off))
2417 0 : goto out_release;
2418 :
2419 0 : ret = shmem_add_to_page_cache(page, mapping, pgoff, NULL,
2420 : gfp & GFP_RECLAIM_MASK, dst_mm);
2421 0 : if (ret)
2422 0 : goto out_release;
2423 :
2424 0 : _dst_pte = mk_pte(page, dst_vma->vm_page_prot);
2425 0 : if (dst_vma->vm_flags & VM_WRITE)
2426 0 : _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
2427 : else {
2428 : /*
2429 : * We don't set the pte dirty if the vma has no
2430 : * VM_WRITE permission, so mark the page dirty or it
2431 : * could be freed from under us. We could do it
2432 : * unconditionally before unlock_page(), but doing it
2433 : * only if VM_WRITE is not set is faster.
2434 : */
2435 0 : set_page_dirty(page);
2436 : }
2437 :
2438 0 : dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
2439 :
2440 0 : ret = -EFAULT;
2441 0 : max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
2442 0 : if (unlikely(offset >= max_off))
2443 0 : goto out_release_unlock;
2444 :
2445 0 : ret = -EEXIST;
2446 0 : if (!pte_none(*dst_pte))
2447 0 : goto out_release_unlock;
2448 :
2449 0 : lru_cache_add(page);
2450 :
2451 0 : spin_lock_irq(&info->lock);
2452 0 : info->alloced++;
2453 0 : inode->i_blocks += BLOCKS_PER_PAGE;
2454 0 : shmem_recalc_inode(inode);
2455 0 : spin_unlock_irq(&info->lock);
2456 :
2457 0 : inc_mm_counter(dst_mm, mm_counter_file(page));
2458 0 : page_add_file_rmap(page, false);
2459 0 : set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
2460 :
2461 : /* No need to invalidate - it was non-present before */
2462 0 : update_mmu_cache(dst_vma, dst_addr, dst_pte);
2463 0 : pte_unmap_unlock(dst_pte, ptl);
2464 0 : unlock_page(page);
2465 0 : ret = 0;
2466 : out:
2467 : return ret;
2468 0 : out_release_unlock:
2469 0 : pte_unmap_unlock(dst_pte, ptl);
2470 0 : ClearPageDirty(page);
2471 0 : delete_from_page_cache(page);
2472 0 : out_release:
2473 0 : unlock_page(page);
2474 0 : put_page(page);
2475 0 : out_unacct_blocks:
2476 0 : shmem_inode_unacct_blocks(inode, 1);
2477 0 : goto out;
2478 : }
2479 :
2480 0 : int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm,
2481 : pmd_t *dst_pmd,
2482 : struct vm_area_struct *dst_vma,
2483 : unsigned long dst_addr,
2484 : unsigned long src_addr,
2485 : struct page **pagep)
2486 : {
2487 0 : return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
2488 : dst_addr, src_addr, false, pagep);
2489 : }
2490 :
2491 0 : int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
2492 : pmd_t *dst_pmd,
2493 : struct vm_area_struct *dst_vma,
2494 : unsigned long dst_addr)
2495 : {
2496 0 : struct page *page = NULL;
2497 :
2498 0 : return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
2499 : dst_addr, 0, true, &page);
2500 : }
2501 :
2502 : #ifdef CONFIG_TMPFS
2503 : static const struct inode_operations shmem_symlink_inode_operations;
2504 : static const struct inode_operations shmem_short_symlink_operations;
2505 :
2506 : #ifdef CONFIG_TMPFS_XATTR
2507 : static int shmem_initxattrs(struct inode *, const struct xattr *, void *);
2508 : #else
2509 : #define shmem_initxattrs NULL
2510 : #endif
2511 :
2512 : static int
2513 712 : shmem_write_begin(struct file *file, struct address_space *mapping,
2514 : loff_t pos, unsigned len, unsigned flags,
2515 : struct page **pagep, void **fsdata)
2516 : {
2517 712 : struct inode *inode = mapping->host;
2518 712 : struct shmem_inode_info *info = SHMEM_I(inode);
2519 712 : pgoff_t index = pos >> PAGE_SHIFT;
2520 :
2521 : /* i_mutex is held by caller */
2522 712 : if (unlikely(info->seals & (F_SEAL_GROW |
2523 : F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) {
2524 0 : if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))
2525 : return -EPERM;
2526 0 : if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size)
2527 : return -EPERM;
2528 : }
2529 :
2530 712 : return shmem_getpage(inode, index, pagep, SGP_WRITE);
2531 : }
2532 :
2533 : static int
2534 712 : shmem_write_end(struct file *file, struct address_space *mapping,
2535 : loff_t pos, unsigned len, unsigned copied,
2536 : struct page *page, void *fsdata)
2537 : {
2538 712 : struct inode *inode = mapping->host;
2539 :
2540 712 : if (pos + copied > inode->i_size)
2541 710 : i_size_write(inode, pos + copied);
2542 :
2543 712 : if (!PageUptodate(page)) {
2544 709 : struct page *head = compound_head(page);
2545 709 : if (PageTransCompound(page)) {
2546 : int i;
2547 :
2548 0 : for (i = 0; i < HPAGE_PMD_NR; i++) {
2549 0 : if (head + i == page)
2550 0 : continue;
2551 0 : clear_highpage(head + i);
2552 0 : flush_dcache_page(head + i);
2553 : }
2554 : }
2555 709 : if (copied < PAGE_SIZE) {
2556 136 : unsigned from = pos & (PAGE_SIZE - 1);
2557 136 : zero_user_segments(page, 0, from,
2558 : from + copied, PAGE_SIZE);
2559 : }
2560 709 : SetPageUptodate(head);
2561 : }
2562 712 : set_page_dirty(page);
2563 712 : unlock_page(page);
2564 712 : put_page(page);
2565 :
2566 712 : return copied;
2567 : }
2568 :
2569 379 : static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
2570 : {
2571 379 : struct file *file = iocb->ki_filp;
2572 379 : struct inode *inode = file_inode(file);
2573 379 : struct address_space *mapping = inode->i_mapping;
2574 379 : pgoff_t index;
2575 379 : unsigned long offset;
2576 379 : enum sgp_type sgp = SGP_READ;
2577 379 : int error = 0;
2578 379 : ssize_t retval = 0;
2579 379 : loff_t *ppos = &iocb->ki_pos;
2580 :
2581 : /*
2582 : * Might this read be for a stacking filesystem? Then when reading
2583 : * holes of a sparse file, we actually need to allocate those pages,
2584 : * and even mark them dirty, so it cannot exceed the max_blocks limit.
2585 : */
2586 379 : if (!iter_is_iovec(to))
2587 4 : sgp = SGP_CACHE;
2588 :
2589 379 : index = *ppos >> PAGE_SHIFT;
2590 379 : offset = *ppos & ~PAGE_MASK;
2591 :
2592 162 : for (;;) {
2593 541 : struct page *page = NULL;
2594 541 : pgoff_t end_index;
2595 541 : unsigned long nr, ret;
2596 541 : loff_t i_size = i_size_read(inode);
2597 :
2598 541 : end_index = i_size >> PAGE_SHIFT;
2599 541 : if (index > end_index)
2600 : break;
2601 541 : if (index == end_index) {
2602 537 : nr = i_size & ~PAGE_MASK;
2603 537 : if (nr <= offset)
2604 : break;
2605 : }
2606 :
2607 187 : error = shmem_getpage(inode, index, &page, sgp);
2608 187 : if (error) {
2609 0 : if (error == -EINVAL)
2610 0 : error = 0;
2611 : break;
2612 : }
2613 187 : if (page) {
2614 187 : if (sgp == SGP_CACHE)
2615 4 : set_page_dirty(page);
2616 187 : unlock_page(page);
2617 : }
2618 :
2619 : /*
2620 : * We must evaluate after, since reads (unlike writes)
2621 : * are called without i_mutex protection against truncate
2622 : */
2623 187 : nr = PAGE_SIZE;
2624 187 : i_size = i_size_read(inode);
2625 187 : end_index = i_size >> PAGE_SHIFT;
2626 187 : if (index == end_index) {
2627 183 : nr = i_size & ~PAGE_MASK;
2628 183 : if (nr <= offset) {
2629 0 : if (page)
2630 0 : put_page(page);
2631 : break;
2632 : }
2633 : }
2634 187 : nr -= offset;
2635 :
2636 187 : if (page) {
2637 : /*
2638 : * If users can be writing to this page using arbitrary
2639 : * virtual addresses, take care about potential aliasing
2640 : * before reading the page on the kernel side.
2641 : */
2642 187 : if (mapping_writably_mapped(mapping))
2643 187 : flush_dcache_page(page);
2644 : /*
2645 : * Mark the page accessed if we read the beginning.
2646 : */
2647 187 : if (!offset)
2648 178 : mark_page_accessed(page);
2649 : } else {
2650 0 : page = ZERO_PAGE(0);
2651 0 : get_page(page);
2652 : }
2653 :
2654 : /*
2655 : * Ok, we have the page, and it's up-to-date, so
2656 : * now we can copy it to user space...
2657 : */
2658 187 : ret = copy_page_to_iter(page, offset, nr, to);
2659 187 : retval += ret;
2660 187 : offset += ret;
2661 187 : index += offset >> PAGE_SHIFT;
2662 187 : offset &= ~PAGE_MASK;
2663 :
2664 187 : put_page(page);
2665 187 : if (!iov_iter_count(to))
2666 : break;
2667 162 : if (ret < nr) {
2668 : error = -EFAULT;
2669 : break;
2670 : }
2671 162 : cond_resched();
2672 : }
2673 :
2674 379 : *ppos = ((loff_t) index << PAGE_SHIFT) + offset;
2675 379 : file_accessed(file);
2676 379 : return retval ? retval : error;
2677 : }
2678 :
2679 31 : static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
2680 : {
2681 31 : struct address_space *mapping = file->f_mapping;
2682 31 : struct inode *inode = mapping->host;
2683 :
2684 31 : if (whence != SEEK_DATA && whence != SEEK_HOLE)
2685 31 : return generic_file_llseek_size(file, offset, whence,
2686 : MAX_LFS_FILESIZE, i_size_read(inode));
2687 0 : if (offset < 0)
2688 : return -ENXIO;
2689 :
2690 0 : inode_lock(inode);
2691 : /* We're holding i_mutex so we can access i_size directly */
2692 0 : offset = mapping_seek_hole_data(mapping, offset, inode->i_size, whence);
2693 0 : if (offset >= 0)
2694 0 : offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE);
2695 0 : inode_unlock(inode);
2696 0 : return offset;
2697 : }
2698 :
2699 2 : static long shmem_fallocate(struct file *file, int mode, loff_t offset,
2700 : loff_t len)
2701 : {
2702 2 : struct inode *inode = file_inode(file);
2703 2 : struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
2704 2 : struct shmem_inode_info *info = SHMEM_I(inode);
2705 2 : struct shmem_falloc shmem_falloc;
2706 2 : pgoff_t start, index, end;
2707 2 : int error;
2708 :
2709 2 : if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2710 : return -EOPNOTSUPP;
2711 :
2712 2 : inode_lock(inode);
2713 :
2714 2 : if (mode & FALLOC_FL_PUNCH_HOLE) {
2715 0 : struct address_space *mapping = file->f_mapping;
2716 0 : loff_t unmap_start = round_up(offset, PAGE_SIZE);
2717 0 : loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1;
2718 0 : DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq);
2719 :
2720 : /* protected by i_mutex */
2721 0 : if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
2722 0 : error = -EPERM;
2723 0 : goto out;
2724 : }
2725 :
2726 0 : shmem_falloc.waitq = &shmem_falloc_waitq;
2727 0 : shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT;
2728 0 : shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
2729 0 : spin_lock(&inode->i_lock);
2730 0 : inode->i_private = &shmem_falloc;
2731 0 : spin_unlock(&inode->i_lock);
2732 :
2733 0 : if ((u64)unmap_end > (u64)unmap_start)
2734 0 : unmap_mapping_range(mapping, unmap_start,
2735 0 : 1 + unmap_end - unmap_start, 0);
2736 0 : shmem_truncate_range(inode, offset, offset + len - 1);
2737 : /* No need to unmap again: hole-punching leaves COWed pages */
2738 :
2739 0 : spin_lock(&inode->i_lock);
2740 0 : inode->i_private = NULL;
2741 0 : wake_up_all(&shmem_falloc_waitq);
2742 0 : WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.head));
2743 0 : spin_unlock(&inode->i_lock);
2744 0 : error = 0;
2745 0 : goto out;
2746 : }
2747 :
2748 : /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
2749 2 : error = inode_newsize_ok(inode, offset + len);
2750 2 : if (error)
2751 0 : goto out;
2752 :
2753 2 : if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
2754 0 : error = -EPERM;
2755 0 : goto out;
2756 : }
2757 :
2758 2 : start = offset >> PAGE_SHIFT;
2759 2 : end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
2760 : /* Try to avoid a swapstorm if len is impossible to satisfy */
2761 2 : if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) {
2762 0 : error = -ENOSPC;
2763 0 : goto out;
2764 : }
2765 :
2766 2 : shmem_falloc.waitq = NULL;
2767 2 : shmem_falloc.start = start;
2768 2 : shmem_falloc.next = start;
2769 2 : shmem_falloc.nr_falloced = 0;
2770 2 : shmem_falloc.nr_unswapped = 0;
2771 2 : spin_lock(&inode->i_lock);
2772 2 : inode->i_private = &shmem_falloc;
2773 2 : spin_unlock(&inode->i_lock);
2774 :
2775 1278 : for (index = start; index < end; index++) {
2776 1274 : struct page *page;
2777 :
2778 : /*
2779 : * Good, the fallocate(2) manpage permits EINTR: we may have
2780 : * been interrupted because we are using up too much memory.
2781 : */
2782 1274 : if (signal_pending(current))
2783 : error = -EINTR;
2784 1274 : else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced)
2785 : error = -ENOMEM;
2786 : else
2787 1274 : error = shmem_getpage(inode, index, &page, SGP_FALLOC);
2788 1274 : if (error) {
2789 : /* Remove the !PageUptodate pages we added */
2790 0 : if (index > start) {
2791 0 : shmem_undo_range(inode,
2792 : (loff_t)start << PAGE_SHIFT,
2793 0 : ((loff_t)index << PAGE_SHIFT) - 1, true);
2794 : }
2795 0 : goto undone;
2796 : }
2797 :
2798 : /*
2799 : * Inform shmem_writepage() how far we have reached.
2800 : * No need for lock or barrier: we have the page lock.
2801 : */
2802 1274 : shmem_falloc.next++;
2803 1274 : if (!PageUptodate(page))
2804 1273 : shmem_falloc.nr_falloced++;
2805 :
2806 : /*
2807 : * If !PageUptodate, leave it that way so that freeable pages
2808 : * can be recognized if we need to rollback on error later.
2809 : * But set_page_dirty so that memory pressure will swap rather
2810 : * than free the pages we are allocating (and SGP_CACHE pages
2811 : * might still be clean: we now need to mark those dirty too).
2812 : */
2813 1274 : set_page_dirty(page);
2814 1274 : unlock_page(page);
2815 1274 : put_page(page);
2816 1274 : cond_resched();
2817 : }
2818 :
2819 2 : if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
2820 2 : i_size_write(inode, offset + len);
2821 2 : inode->i_ctime = current_time(inode);
2822 2 : undone:
2823 2 : spin_lock(&inode->i_lock);
2824 2 : inode->i_private = NULL;
2825 2 : spin_unlock(&inode->i_lock);
2826 2 : out:
2827 2 : inode_unlock(inode);
2828 2 : return error;
2829 : }
2830 :
2831 136 : static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
2832 : {
2833 136 : struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
2834 :
2835 136 : buf->f_type = TMPFS_MAGIC;
2836 136 : buf->f_bsize = PAGE_SIZE;
2837 136 : buf->f_namelen = NAME_MAX;
2838 136 : if (sbinfo->max_blocks) {
2839 136 : buf->f_blocks = sbinfo->max_blocks;
2840 272 : buf->f_bavail =
2841 136 : buf->f_bfree = sbinfo->max_blocks -
2842 136 : percpu_counter_sum(&sbinfo->used_blocks);
2843 : }
2844 136 : if (sbinfo->max_inodes) {
2845 136 : buf->f_files = sbinfo->max_inodes;
2846 136 : buf->f_ffree = sbinfo->free_inodes;
2847 : }
2848 : /* else leave those fields 0 like simple_statfs */
2849 136 : return 0;
2850 : }
2851 :
2852 : /*
2853 : * File creation. Allocate an inode, and we're done..
2854 : */
2855 : static int
2856 1422 : shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
2857 : struct dentry *dentry, umode_t mode, dev_t dev)
2858 : {
2859 1422 : struct inode *inode;
2860 1422 : int error = -ENOSPC;
2861 :
2862 1422 : inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
2863 1422 : if (inode) {
2864 1422 : error = simple_acl_create(dir, inode);
2865 1422 : if (error)
2866 : goto out_iput;
2867 2844 : error = security_inode_init_security(inode, dir,
2868 1422 : &dentry->d_name,
2869 : shmem_initxattrs, NULL);
2870 1422 : if (error && error != -EOPNOTSUPP)
2871 0 : goto out_iput;
2872 :
2873 1422 : error = 0;
2874 1422 : dir->i_size += BOGO_DIRENT_SIZE;
2875 1422 : dir->i_ctime = dir->i_mtime = current_time(dir);
2876 1422 : d_instantiate(dentry, inode);
2877 1422 : dget(dentry); /* Extra count - pin the dentry in core */
2878 : }
2879 : return error;
2880 0 : out_iput:
2881 0 : iput(inode);
2882 0 : return error;
2883 : }
2884 :
2885 : static int
2886 5 : shmem_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
2887 : struct dentry *dentry, umode_t mode)
2888 : {
2889 5 : struct inode *inode;
2890 5 : int error = -ENOSPC;
2891 :
2892 5 : inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE);
2893 5 : if (inode) {
2894 5 : error = security_inode_init_security(inode, dir,
2895 : NULL,
2896 : shmem_initxattrs, NULL);
2897 5 : if (error && error != -EOPNOTSUPP)
2898 0 : goto out_iput;
2899 5 : error = simple_acl_create(dir, inode);
2900 5 : if (error)
2901 : goto out_iput;
2902 5 : d_tmpfile(dentry, inode);
2903 : }
2904 : return error;
2905 0 : out_iput:
2906 0 : iput(inode);
2907 0 : return error;
2908 : }
2909 :
2910 510 : static int shmem_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
2911 : struct dentry *dentry, umode_t mode)
2912 : {
2913 510 : int error;
2914 :
2915 510 : if ((error = shmem_mknod(&init_user_ns, dir, dentry,
2916 : mode | S_IFDIR, 0)))
2917 : return error;
2918 510 : inc_nlink(dir);
2919 510 : return 0;
2920 : }
2921 :
2922 746 : static int shmem_create(struct user_namespace *mnt_userns, struct inode *dir,
2923 : struct dentry *dentry, umode_t mode, bool excl)
2924 : {
2925 746 : return shmem_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
2926 : }
2927 :
2928 : /*
2929 : * Link a file..
2930 : */
2931 19 : static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
2932 : {
2933 19 : struct inode *inode = d_inode(old_dentry);
2934 19 : int ret = 0;
2935 :
2936 : /*
2937 : * No ordinary (disk based) filesystem counts links as inodes;
2938 : * but each new link needs a new dentry, pinning lowmem, and
2939 : * tmpfs dentries cannot be pruned until they are unlinked.
2940 : * But if an O_TMPFILE file is linked into the tmpfs, the
2941 : * first link must skip that, to get the accounting right.
2942 : */
2943 19 : if (inode->i_nlink) {
2944 16 : ret = shmem_reserve_inode(inode->i_sb, NULL);
2945 16 : if (ret)
2946 0 : goto out;
2947 : }
2948 :
2949 19 : dir->i_size += BOGO_DIRENT_SIZE;
2950 19 : inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2951 19 : inc_nlink(inode);
2952 19 : ihold(inode); /* New dentry reference */
2953 19 : dget(dentry); /* Extra pinning count for the created dentry */
2954 19 : d_instantiate(dentry, inode);
2955 19 : out:
2956 19 : return ret;
2957 : }
2958 :
2959 1043 : static int shmem_unlink(struct inode *dir, struct dentry *dentry)
2960 : {
2961 1043 : struct inode *inode = d_inode(dentry);
2962 :
2963 1043 : if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
2964 16 : shmem_free_inode(inode->i_sb);
2965 :
2966 1043 : dir->i_size -= BOGO_DIRENT_SIZE;
2967 1043 : inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2968 1043 : drop_nlink(inode);
2969 1043 : dput(dentry); /* Undo the count from "create" - this does all the work */
2970 1043 : return 0;
2971 : }
2972 :
2973 755 : static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
2974 : {
2975 755 : if (!simple_empty(dentry))
2976 : return -ENOTEMPTY;
2977 :
2978 423 : drop_nlink(d_inode(dentry));
2979 423 : drop_nlink(dir);
2980 423 : return shmem_unlink(dir, dentry);
2981 : }
2982 :
2983 4 : static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
2984 : {
2985 4 : bool old_is_dir = d_is_dir(old_dentry);
2986 4 : bool new_is_dir = d_is_dir(new_dentry);
2987 :
2988 4 : if (old_dir != new_dir && old_is_dir != new_is_dir) {
2989 0 : if (old_is_dir) {
2990 0 : drop_nlink(old_dir);
2991 0 : inc_nlink(new_dir);
2992 : } else {
2993 0 : drop_nlink(new_dir);
2994 0 : inc_nlink(old_dir);
2995 : }
2996 : }
2997 4 : old_dir->i_ctime = old_dir->i_mtime =
2998 4 : new_dir->i_ctime = new_dir->i_mtime =
2999 4 : d_inode(old_dentry)->i_ctime =
3000 4 : d_inode(new_dentry)->i_ctime = current_time(old_dir);
3001 :
3002 4 : return 0;
3003 : }
3004 :
3005 2 : static int shmem_whiteout(struct user_namespace *mnt_userns,
3006 : struct inode *old_dir, struct dentry *old_dentry)
3007 : {
3008 2 : struct dentry *whiteout;
3009 2 : int error;
3010 :
3011 2 : whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
3012 2 : if (!whiteout)
3013 : return -ENOMEM;
3014 :
3015 2 : error = shmem_mknod(&init_user_ns, old_dir, whiteout,
3016 : S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
3017 2 : dput(whiteout);
3018 2 : if (error)
3019 : return error;
3020 :
3021 : /*
3022 : * Cheat and hash the whiteout while the old dentry is still in
3023 : * place, instead of playing games with FS_RENAME_DOES_D_MOVE.
3024 : *
3025 : * d_lookup() will consistently find one of them at this point,
3026 : * not sure which one, but that isn't even important.
3027 : */
3028 2 : d_rehash(whiteout);
3029 2 : return 0;
3030 : }
3031 :
3032 : /*
3033 : * The VFS layer already does all the dentry stuff for rename,
3034 : * we just have to decrement the usage count for the target if
3035 : * it exists so that the VFS layer correctly free's it when it
3036 : * gets overwritten.
3037 : */
3038 289 : static int shmem_rename2(struct user_namespace *mnt_userns,
3039 : struct inode *old_dir, struct dentry *old_dentry,
3040 : struct inode *new_dir, struct dentry *new_dentry,
3041 : unsigned int flags)
3042 : {
3043 289 : struct inode *inode = d_inode(old_dentry);
3044 289 : int they_are_dirs = S_ISDIR(inode->i_mode);
3045 :
3046 289 : if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3047 : return -EINVAL;
3048 :
3049 289 : if (flags & RENAME_EXCHANGE)
3050 4 : return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry);
3051 :
3052 285 : if (!simple_empty(new_dentry))
3053 : return -ENOTEMPTY;
3054 :
3055 285 : if (flags & RENAME_WHITEOUT) {
3056 2 : int error;
3057 :
3058 2 : error = shmem_whiteout(&init_user_ns, old_dir, old_dentry);
3059 2 : if (error)
3060 : return error;
3061 : }
3062 :
3063 285 : if (d_really_is_positive(new_dentry)) {
3064 61 : (void) shmem_unlink(new_dir, new_dentry);
3065 61 : if (they_are_dirs) {
3066 1 : drop_nlink(d_inode(new_dentry));
3067 1 : drop_nlink(old_dir);
3068 : }
3069 224 : } else if (they_are_dirs) {
3070 1 : drop_nlink(old_dir);
3071 1 : inc_nlink(new_dir);
3072 : }
3073 :
3074 285 : old_dir->i_size -= BOGO_DIRENT_SIZE;
3075 285 : new_dir->i_size += BOGO_DIRENT_SIZE;
3076 570 : old_dir->i_ctime = old_dir->i_mtime =
3077 285 : new_dir->i_ctime = new_dir->i_mtime =
3078 285 : inode->i_ctime = current_time(old_dir);
3079 285 : return 0;
3080 : }
3081 :
3082 208 : static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir,
3083 : struct dentry *dentry, const char *symname)
3084 : {
3085 208 : int error;
3086 208 : int len;
3087 208 : struct inode *inode;
3088 208 : struct page *page;
3089 :
3090 208 : len = strlen(symname) + 1;
3091 208 : if (len > PAGE_SIZE)
3092 : return -ENAMETOOLONG;
3093 :
3094 208 : inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK | 0777, 0,
3095 : VM_NORESERVE);
3096 208 : if (!inode)
3097 : return -ENOSPC;
3098 :
3099 208 : error = security_inode_init_security(inode, dir, &dentry->d_name,
3100 : shmem_initxattrs, NULL);
3101 208 : if (error && error != -EOPNOTSUPP) {
3102 0 : iput(inode);
3103 0 : return error;
3104 : }
3105 :
3106 208 : inode->i_size = len-1;
3107 208 : if (len <= SHORT_SYMLINK_LEN) {
3108 208 : inode->i_link = kmemdup(symname, len, GFP_KERNEL);
3109 208 : if (!inode->i_link) {
3110 0 : iput(inode);
3111 0 : return -ENOMEM;
3112 : }
3113 208 : inode->i_op = &shmem_short_symlink_operations;
3114 : } else {
3115 0 : inode_nohighmem(inode);
3116 0 : error = shmem_getpage(inode, 0, &page, SGP_WRITE);
3117 0 : if (error) {
3118 0 : iput(inode);
3119 0 : return error;
3120 : }
3121 0 : inode->i_mapping->a_ops = &shmem_aops;
3122 0 : inode->i_op = &shmem_symlink_inode_operations;
3123 0 : memcpy(page_address(page), symname, len);
3124 0 : SetPageUptodate(page);
3125 0 : set_page_dirty(page);
3126 0 : unlock_page(page);
3127 0 : put_page(page);
3128 : }
3129 208 : dir->i_size += BOGO_DIRENT_SIZE;
3130 208 : dir->i_ctime = dir->i_mtime = current_time(dir);
3131 208 : d_instantiate(dentry, inode);
3132 208 : dget(dentry);
3133 : return 0;
3134 : }
3135 :
3136 0 : static void shmem_put_link(void *arg)
3137 : {
3138 0 : mark_page_accessed(arg);
3139 0 : put_page(arg);
3140 0 : }
3141 :
3142 0 : static const char *shmem_get_link(struct dentry *dentry,
3143 : struct inode *inode,
3144 : struct delayed_call *done)
3145 : {
3146 0 : struct page *page = NULL;
3147 0 : int error;
3148 0 : if (!dentry) {
3149 0 : page = find_get_page(inode->i_mapping, 0);
3150 0 : if (!page)
3151 0 : return ERR_PTR(-ECHILD);
3152 0 : if (!PageUptodate(page)) {
3153 0 : put_page(page);
3154 0 : return ERR_PTR(-ECHILD);
3155 : }
3156 : } else {
3157 0 : error = shmem_getpage(inode, 0, &page, SGP_READ);
3158 0 : if (error)
3159 0 : return ERR_PTR(error);
3160 0 : unlock_page(page);
3161 : }
3162 0 : set_delayed_call(done, shmem_put_link, page);
3163 0 : return page_address(page);
3164 : }
3165 :
3166 : #ifdef CONFIG_TMPFS_XATTR
3167 : /*
3168 : * Superblocks without xattr inode operations may get some security.* xattr
3169 : * support from the LSM "for free". As soon as we have any other xattrs
3170 : * like ACLs, we also need to implement the security.* handlers at
3171 : * filesystem level, though.
3172 : */
3173 :
3174 : /*
3175 : * Callback for security_inode_init_security() for acquiring xattrs.
3176 : */
3177 0 : static int shmem_initxattrs(struct inode *inode,
3178 : const struct xattr *xattr_array,
3179 : void *fs_info)
3180 : {
3181 0 : struct shmem_inode_info *info = SHMEM_I(inode);
3182 0 : const struct xattr *xattr;
3183 0 : struct simple_xattr *new_xattr;
3184 0 : size_t len;
3185 :
3186 0 : for (xattr = xattr_array; xattr->name != NULL; xattr++) {
3187 0 : new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
3188 0 : if (!new_xattr)
3189 : return -ENOMEM;
3190 :
3191 0 : len = strlen(xattr->name) + 1;
3192 0 : new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
3193 : GFP_KERNEL);
3194 0 : if (!new_xattr->name) {
3195 0 : kvfree(new_xattr);
3196 0 : return -ENOMEM;
3197 : }
3198 :
3199 0 : memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
3200 : XATTR_SECURITY_PREFIX_LEN);
3201 0 : memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
3202 0 : xattr->name, len);
3203 :
3204 0 : simple_xattr_list_add(&info->xattrs, new_xattr);
3205 : }
3206 :
3207 : return 0;
3208 : }
3209 :
3210 292 : static int shmem_xattr_handler_get(const struct xattr_handler *handler,
3211 : struct dentry *unused, struct inode *inode,
3212 : const char *name, void *buffer, size_t size)
3213 : {
3214 292 : struct shmem_inode_info *info = SHMEM_I(inode);
3215 :
3216 292 : name = xattr_full_name(handler, name);
3217 292 : return simple_xattr_get(&info->xattrs, name, buffer, size);
3218 : }
3219 :
3220 14 : static int shmem_xattr_handler_set(const struct xattr_handler *handler,
3221 : struct user_namespace *mnt_userns,
3222 : struct dentry *unused, struct inode *inode,
3223 : const char *name, const void *value,
3224 : size_t size, int flags)
3225 : {
3226 14 : struct shmem_inode_info *info = SHMEM_I(inode);
3227 :
3228 14 : name = xattr_full_name(handler, name);
3229 14 : return simple_xattr_set(&info->xattrs, name, value, size, flags, NULL);
3230 : }
3231 :
3232 : static const struct xattr_handler shmem_security_xattr_handler = {
3233 : .prefix = XATTR_SECURITY_PREFIX,
3234 : .get = shmem_xattr_handler_get,
3235 : .set = shmem_xattr_handler_set,
3236 : };
3237 :
3238 : static const struct xattr_handler shmem_trusted_xattr_handler = {
3239 : .prefix = XATTR_TRUSTED_PREFIX,
3240 : .get = shmem_xattr_handler_get,
3241 : .set = shmem_xattr_handler_set,
3242 : };
3243 :
3244 : static const struct xattr_handler *shmem_xattr_handlers[] = {
3245 : #ifdef CONFIG_TMPFS_POSIX_ACL
3246 : &posix_acl_access_xattr_handler,
3247 : &posix_acl_default_xattr_handler,
3248 : #endif
3249 : &shmem_security_xattr_handler,
3250 : &shmem_trusted_xattr_handler,
3251 : NULL
3252 : };
3253 :
3254 4 : static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
3255 : {
3256 4 : struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
3257 4 : return simple_xattr_list(d_inode(dentry), &info->xattrs, buffer, size);
3258 : }
3259 : #endif /* CONFIG_TMPFS_XATTR */
3260 :
3261 : static const struct inode_operations shmem_short_symlink_operations = {
3262 : .get_link = simple_get_link,
3263 : #ifdef CONFIG_TMPFS_XATTR
3264 : .listxattr = shmem_listxattr,
3265 : #endif
3266 : };
3267 :
3268 : static const struct inode_operations shmem_symlink_inode_operations = {
3269 : .get_link = shmem_get_link,
3270 : #ifdef CONFIG_TMPFS_XATTR
3271 : .listxattr = shmem_listxattr,
3272 : #endif
3273 : };
3274 :
3275 0 : static struct dentry *shmem_get_parent(struct dentry *child)
3276 : {
3277 0 : return ERR_PTR(-ESTALE);
3278 : }
3279 :
3280 0 : static int shmem_match(struct inode *ino, void *vfh)
3281 : {
3282 0 : __u32 *fh = vfh;
3283 0 : __u64 inum = fh[2];
3284 0 : inum = (inum << 32) | fh[1];
3285 0 : return ino->i_ino == inum && fh[0] == ino->i_generation;
3286 : }
3287 :
3288 : /* Find any alias of inode, but prefer a hashed alias */
3289 0 : static struct dentry *shmem_find_alias(struct inode *inode)
3290 : {
3291 0 : struct dentry *alias = d_find_alias(inode);
3292 :
3293 0 : return alias ?: d_find_any_alias(inode);
3294 : }
3295 :
3296 :
3297 0 : static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
3298 : struct fid *fid, int fh_len, int fh_type)
3299 : {
3300 0 : struct inode *inode;
3301 0 : struct dentry *dentry = NULL;
3302 0 : u64 inum;
3303 :
3304 0 : if (fh_len < 3)
3305 : return NULL;
3306 :
3307 0 : inum = fid->raw[2];
3308 0 : inum = (inum << 32) | fid->raw[1];
3309 :
3310 0 : inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
3311 0 : shmem_match, fid->raw);
3312 0 : if (inode) {
3313 0 : dentry = shmem_find_alias(inode);
3314 0 : iput(inode);
3315 : }
3316 :
3317 : return dentry;
3318 : }
3319 :
3320 0 : static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len,
3321 : struct inode *parent)
3322 : {
3323 0 : if (*len < 3) {
3324 0 : *len = 3;
3325 0 : return FILEID_INVALID;
3326 : }
3327 :
3328 0 : if (inode_unhashed(inode)) {
3329 : /* Unfortunately insert_inode_hash is not idempotent,
3330 : * so as we hash inodes here rather than at creation
3331 : * time, we need a lock to ensure we only try
3332 : * to do it once
3333 : */
3334 0 : static DEFINE_SPINLOCK(lock);
3335 0 : spin_lock(&lock);
3336 0 : if (inode_unhashed(inode))
3337 0 : __insert_inode_hash(inode,
3338 0 : inode->i_ino + inode->i_generation);
3339 0 : spin_unlock(&lock);
3340 : }
3341 :
3342 0 : fh[0] = inode->i_generation;
3343 0 : fh[1] = inode->i_ino;
3344 0 : fh[2] = ((__u64)inode->i_ino) >> 32;
3345 :
3346 0 : *len = 3;
3347 0 : return 1;
3348 : }
3349 :
3350 : static const struct export_operations shmem_export_ops = {
3351 : .get_parent = shmem_get_parent,
3352 : .encode_fh = shmem_encode_fh,
3353 : .fh_to_dentry = shmem_fh_to_dentry,
3354 : };
3355 :
3356 : enum shmem_param {
3357 : Opt_gid,
3358 : Opt_huge,
3359 : Opt_mode,
3360 : Opt_mpol,
3361 : Opt_nr_blocks,
3362 : Opt_nr_inodes,
3363 : Opt_size,
3364 : Opt_uid,
3365 : Opt_inode32,
3366 : Opt_inode64,
3367 : };
3368 :
3369 : static const struct constant_table shmem_param_enums_huge[] = {
3370 : {"never", SHMEM_HUGE_NEVER },
3371 : {"always", SHMEM_HUGE_ALWAYS },
3372 : {"within_size", SHMEM_HUGE_WITHIN_SIZE },
3373 : {"advise", SHMEM_HUGE_ADVISE },
3374 : {}
3375 : };
3376 :
3377 : const struct fs_parameter_spec shmem_fs_parameters[] = {
3378 : fsparam_u32 ("gid", Opt_gid),
3379 : fsparam_enum ("huge", Opt_huge, shmem_param_enums_huge),
3380 : fsparam_u32oct("mode", Opt_mode),
3381 : fsparam_string("mpol", Opt_mpol),
3382 : fsparam_string("nr_blocks", Opt_nr_blocks),
3383 : fsparam_string("nr_inodes", Opt_nr_inodes),
3384 : fsparam_string("size", Opt_size),
3385 : fsparam_u32 ("uid", Opt_uid),
3386 : fsparam_flag ("inode32", Opt_inode32),
3387 : fsparam_flag ("inode64", Opt_inode64),
3388 : {}
3389 : };
3390 :
3391 304 : static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
3392 : {
3393 304 : struct shmem_options *ctx = fc->fs_private;
3394 304 : struct fs_parse_result result;
3395 304 : unsigned long long size;
3396 304 : char *rest;
3397 304 : int opt;
3398 :
3399 304 : opt = fs_parse(fc, shmem_fs_parameters, param, &result);
3400 304 : if (opt < 0)
3401 : return opt;
3402 :
3403 201 : switch (opt) {
3404 96 : case Opt_size:
3405 96 : size = memparse(param->string, &rest);
3406 96 : if (*rest == '%') {
3407 0 : size <<= PAGE_SHIFT;
3408 0 : size *= totalram_pages();
3409 0 : do_div(size, 100);
3410 0 : rest++;
3411 : }
3412 96 : if (*rest)
3413 0 : goto bad_value;
3414 96 : ctx->blocks = DIV_ROUND_UP(size, PAGE_SIZE);
3415 96 : ctx->seen |= SHMEM_SEEN_BLOCKS;
3416 96 : break;
3417 0 : case Opt_nr_blocks:
3418 0 : ctx->blocks = memparse(param->string, &rest);
3419 0 : if (*rest)
3420 0 : goto bad_value;
3421 0 : ctx->seen |= SHMEM_SEEN_BLOCKS;
3422 0 : break;
3423 0 : case Opt_nr_inodes:
3424 0 : ctx->inodes = memparse(param->string, &rest);
3425 0 : if (*rest)
3426 0 : goto bad_value;
3427 0 : ctx->seen |= SHMEM_SEEN_INODES;
3428 0 : break;
3429 103 : case Opt_mode:
3430 103 : ctx->mode = result.uint_32 & 07777;
3431 103 : break;
3432 1 : case Opt_uid:
3433 1 : ctx->uid = make_kuid(current_user_ns(), result.uint_32);
3434 1 : if (!uid_valid(ctx->uid))
3435 0 : goto bad_value;
3436 : break;
3437 1 : case Opt_gid:
3438 1 : ctx->gid = make_kgid(current_user_ns(), result.uint_32);
3439 1 : if (!gid_valid(ctx->gid))
3440 0 : goto bad_value;
3441 : break;
3442 0 : case Opt_huge:
3443 0 : ctx->huge = result.uint_32;
3444 0 : if (ctx->huge != SHMEM_HUGE_NEVER &&
3445 : !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
3446 : has_transparent_hugepage()))
3447 : goto unsupported_parameter;
3448 0 : ctx->seen |= SHMEM_SEEN_HUGE;
3449 0 : break;
3450 : case Opt_mpol:
3451 0 : if (IS_ENABLED(CONFIG_NUMA)) {
3452 0 : mpol_put(ctx->mpol);
3453 0 : ctx->mpol = NULL;
3454 0 : if (mpol_parse_str(param->string, &ctx->mpol))
3455 0 : goto bad_value;
3456 : break;
3457 : }
3458 : goto unsupported_parameter;
3459 0 : case Opt_inode32:
3460 0 : ctx->full_inums = false;
3461 0 : ctx->seen |= SHMEM_SEEN_INUMS;
3462 0 : break;
3463 : case Opt_inode64:
3464 0 : if (sizeof(ino_t) < 8) {
3465 : return invalfc(fc,
3466 : "Cannot use inode64 with <64bit inums in kernel\n");
3467 : }
3468 0 : ctx->full_inums = true;
3469 0 : ctx->seen |= SHMEM_SEEN_INUMS;
3470 0 : break;
3471 : }
3472 : return 0;
3473 :
3474 : unsupported_parameter:
3475 : return invalfc(fc, "Unsupported parameter '%s'", param->key);
3476 0 : bad_value:
3477 0 : return invalfc(fc, "Bad value for '%s'", param->key);
3478 : }
3479 :
3480 104 : static int shmem_parse_options(struct fs_context *fc, void *data)
3481 : {
3482 104 : char *options = data;
3483 :
3484 104 : if (options) {
3485 103 : int err = security_sb_eat_lsm_opts(options, &fc->security);
3486 103 : if (err)
3487 : return err;
3488 : }
3489 :
3490 305 : while (options != NULL) {
3491 201 : char *this_char = options;
3492 201 : for (;;) {
3493 : /*
3494 : * NUL-terminate this option: unfortunately,
3495 : * mount options form a comma-separated list,
3496 : * but mpol's nodelist may also contain commas.
3497 : */
3498 201 : options = strchr(options, ',');
3499 201 : if (options == NULL)
3500 : break;
3501 98 : options++;
3502 98 : if (!isdigit(*options)) {
3503 98 : options[-1] = '\0';
3504 98 : break;
3505 : }
3506 : }
3507 201 : if (*this_char) {
3508 201 : char *value = strchr(this_char,'=');
3509 201 : size_t len = 0;
3510 201 : int err;
3511 :
3512 201 : if (value) {
3513 201 : *value++ = '\0';
3514 201 : len = strlen(value);
3515 : }
3516 201 : err = vfs_parse_fs_string(fc, this_char, value, len);
3517 201 : if (err < 0)
3518 0 : return err;
3519 : }
3520 : }
3521 : return 0;
3522 : }
3523 :
3524 : /*
3525 : * Reconfigure a shmem filesystem.
3526 : *
3527 : * Note that we disallow change from limited->unlimited blocks/inodes while any
3528 : * are in use; but we must separately disallow unlimited->limited, because in
3529 : * that case we have no record of how much is already in use.
3530 : */
3531 1 : static int shmem_reconfigure(struct fs_context *fc)
3532 : {
3533 1 : struct shmem_options *ctx = fc->fs_private;
3534 1 : struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb);
3535 1 : unsigned long inodes;
3536 1 : const char *err;
3537 :
3538 1 : spin_lock(&sbinfo->stat_lock);
3539 1 : inodes = sbinfo->max_inodes - sbinfo->free_inodes;
3540 1 : if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) {
3541 0 : if (!sbinfo->max_blocks) {
3542 0 : err = "Cannot retroactively limit size";
3543 0 : goto out;
3544 : }
3545 0 : if (percpu_counter_compare(&sbinfo->used_blocks,
3546 : ctx->blocks) > 0) {
3547 0 : err = "Too small a size for current use";
3548 0 : goto out;
3549 : }
3550 : }
3551 1 : if ((ctx->seen & SHMEM_SEEN_INODES) && ctx->inodes) {
3552 0 : if (!sbinfo->max_inodes) {
3553 0 : err = "Cannot retroactively limit inodes";
3554 0 : goto out;
3555 : }
3556 0 : if (ctx->inodes < inodes) {
3557 0 : err = "Too few inodes for current use";
3558 0 : goto out;
3559 : }
3560 : }
3561 :
3562 1 : if ((ctx->seen & SHMEM_SEEN_INUMS) && !ctx->full_inums &&
3563 0 : sbinfo->next_ino > UINT_MAX) {
3564 0 : err = "Current inum too high to switch to 32-bit inums";
3565 0 : goto out;
3566 : }
3567 :
3568 1 : if (ctx->seen & SHMEM_SEEN_HUGE)
3569 0 : sbinfo->huge = ctx->huge;
3570 1 : if (ctx->seen & SHMEM_SEEN_INUMS)
3571 0 : sbinfo->full_inums = ctx->full_inums;
3572 1 : if (ctx->seen & SHMEM_SEEN_BLOCKS)
3573 0 : sbinfo->max_blocks = ctx->blocks;
3574 1 : if (ctx->seen & SHMEM_SEEN_INODES) {
3575 0 : sbinfo->max_inodes = ctx->inodes;
3576 0 : sbinfo->free_inodes = ctx->inodes - inodes;
3577 : }
3578 :
3579 : /*
3580 : * Preserve previous mempolicy unless mpol remount option was specified.
3581 : */
3582 1 : if (ctx->mpol) {
3583 0 : mpol_put(sbinfo->mpol);
3584 0 : sbinfo->mpol = ctx->mpol; /* transfers initial ref */
3585 0 : ctx->mpol = NULL;
3586 : }
3587 1 : spin_unlock(&sbinfo->stat_lock);
3588 1 : return 0;
3589 0 : out:
3590 0 : spin_unlock(&sbinfo->stat_lock);
3591 0 : return invalfc(fc, "%s", err);
3592 : }
3593 :
3594 1914 : static int shmem_show_options(struct seq_file *seq, struct dentry *root)
3595 : {
3596 1914 : struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb);
3597 :
3598 1914 : if (sbinfo->max_blocks != shmem_default_max_blocks())
3599 700 : seq_printf(seq, ",size=%luk",
3600 700 : sbinfo->max_blocks << (PAGE_SHIFT - 10));
3601 1913 : if (sbinfo->max_inodes != shmem_default_max_inodes())
3602 217 : seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
3603 1913 : if (sbinfo->mode != (0777 | S_ISVTX))
3604 1350 : seq_printf(seq, ",mode=%03ho", sbinfo->mode);
3605 1913 : if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
3606 0 : seq_printf(seq, ",uid=%u",
3607 : from_kuid_munged(&init_user_ns, sbinfo->uid));
3608 1913 : if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
3609 0 : seq_printf(seq, ",gid=%u",
3610 : from_kgid_munged(&init_user_ns, sbinfo->gid));
3611 :
3612 : /*
3613 : * Showing inode{64,32} might be useful even if it's the system default,
3614 : * since then people don't have to resort to checking both here and
3615 : * /proc/config.gz to confirm 64-bit inums were successfully applied
3616 : * (which may not even exist if IKCONFIG_PROC isn't enabled).
3617 : *
3618 : * We hide it when inode64 isn't the default and we are using 32-bit
3619 : * inodes, since that probably just means the feature isn't even under
3620 : * consideration.
3621 : *
3622 : * As such:
3623 : *
3624 : * +-----------------+-----------------+
3625 : * | TMPFS_INODE64=y | TMPFS_INODE64=n |
3626 : * +------------------+-----------------+-----------------+
3627 : * | full_inums=true | show | show |
3628 : * | full_inums=false | show | hide |
3629 : * +------------------+-----------------+-----------------+
3630 : *
3631 : */
3632 1913 : if (IS_ENABLED(CONFIG_TMPFS_INODE64) || sbinfo->full_inums)
3633 0 : seq_printf(seq, ",inode%d", (sbinfo->full_inums ? 64 : 32));
3634 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3635 : /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
3636 1913 : if (sbinfo->huge)
3637 0 : seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge));
3638 : #endif
3639 1913 : shmem_show_mpol(seq, sbinfo->mpol);
3640 1915 : return 0;
3641 : }
3642 :
3643 : #endif /* CONFIG_TMPFS */
3644 :
3645 95 : static void shmem_put_super(struct super_block *sb)
3646 : {
3647 95 : struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
3648 :
3649 95 : free_percpu(sbinfo->ino_batch);
3650 95 : percpu_counter_destroy(&sbinfo->used_blocks);
3651 95 : mpol_put(sbinfo->mpol);
3652 95 : kfree(sbinfo);
3653 95 : sb->s_fs_info = NULL;
3654 95 : }
3655 :
3656 103 : static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
3657 : {
3658 103 : struct shmem_options *ctx = fc->fs_private;
3659 103 : struct inode *inode;
3660 103 : struct shmem_sb_info *sbinfo;
3661 103 : int err = -ENOMEM;
3662 :
3663 : /* Round up to L1_CACHE_BYTES to resist false sharing */
3664 103 : sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info),
3665 : L1_CACHE_BYTES), GFP_KERNEL);
3666 103 : if (!sbinfo)
3667 : return -ENOMEM;
3668 :
3669 103 : sb->s_fs_info = sbinfo;
3670 :
3671 : #ifdef CONFIG_TMPFS
3672 : /*
3673 : * Per default we only allow half of the physical ram per
3674 : * tmpfs instance, limiting inodes to one per page of lowmem;
3675 : * but the internal instance is left unlimited.
3676 : */
3677 103 : if (!(sb->s_flags & SB_KERNMOUNT)) {
3678 102 : if (!(ctx->seen & SHMEM_SEEN_BLOCKS))
3679 6 : ctx->blocks = shmem_default_max_blocks();
3680 102 : if (!(ctx->seen & SHMEM_SEEN_INODES))
3681 102 : ctx->inodes = shmem_default_max_inodes();
3682 102 : if (!(ctx->seen & SHMEM_SEEN_INUMS))
3683 102 : ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64);
3684 : } else {
3685 1 : sb->s_flags |= SB_NOUSER;
3686 : }
3687 103 : sb->s_export_op = &shmem_export_ops;
3688 103 : sb->s_flags |= SB_NOSEC;
3689 : #else
3690 : sb->s_flags |= SB_NOUSER;
3691 : #endif
3692 103 : sbinfo->max_blocks = ctx->blocks;
3693 103 : sbinfo->free_inodes = sbinfo->max_inodes = ctx->inodes;
3694 103 : if (sb->s_flags & SB_KERNMOUNT) {
3695 1 : sbinfo->ino_batch = alloc_percpu(ino_t);
3696 1 : if (!sbinfo->ino_batch)
3697 0 : goto failed;
3698 : }
3699 103 : sbinfo->uid = ctx->uid;
3700 103 : sbinfo->gid = ctx->gid;
3701 103 : sbinfo->full_inums = ctx->full_inums;
3702 103 : sbinfo->mode = ctx->mode;
3703 103 : sbinfo->huge = ctx->huge;
3704 103 : sbinfo->mpol = ctx->mpol;
3705 103 : ctx->mpol = NULL;
3706 :
3707 103 : spin_lock_init(&sbinfo->stat_lock);
3708 103 : if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
3709 0 : goto failed;
3710 103 : spin_lock_init(&sbinfo->shrinklist_lock);
3711 103 : INIT_LIST_HEAD(&sbinfo->shrinklist);
3712 :
3713 103 : sb->s_maxbytes = MAX_LFS_FILESIZE;
3714 103 : sb->s_blocksize = PAGE_SIZE;
3715 103 : sb->s_blocksize_bits = PAGE_SHIFT;
3716 103 : sb->s_magic = TMPFS_MAGIC;
3717 103 : sb->s_op = &shmem_ops;
3718 103 : sb->s_time_gran = 1;
3719 : #ifdef CONFIG_TMPFS_XATTR
3720 103 : sb->s_xattr = shmem_xattr_handlers;
3721 : #endif
3722 : #ifdef CONFIG_TMPFS_POSIX_ACL
3723 : sb->s_flags |= SB_POSIXACL;
3724 : #endif
3725 103 : uuid_gen(&sb->s_uuid);
3726 :
3727 103 : inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
3728 103 : if (!inode)
3729 0 : goto failed;
3730 103 : inode->i_uid = sbinfo->uid;
3731 103 : inode->i_gid = sbinfo->gid;
3732 103 : sb->s_root = d_make_root(inode);
3733 103 : if (!sb->s_root)
3734 0 : goto failed;
3735 : return 0;
3736 :
3737 0 : failed:
3738 0 : shmem_put_super(sb);
3739 0 : return err;
3740 : }
3741 :
3742 103 : static int shmem_get_tree(struct fs_context *fc)
3743 : {
3744 103 : return get_tree_nodev(fc, shmem_fill_super);
3745 : }
3746 :
3747 104 : static void shmem_free_fc(struct fs_context *fc)
3748 : {
3749 104 : struct shmem_options *ctx = fc->fs_private;
3750 :
3751 104 : if (ctx) {
3752 104 : mpol_put(ctx->mpol);
3753 104 : kfree(ctx);
3754 : }
3755 104 : }
3756 :
3757 : static const struct fs_context_operations shmem_fs_context_ops = {
3758 : .free = shmem_free_fc,
3759 : .get_tree = shmem_get_tree,
3760 : #ifdef CONFIG_TMPFS
3761 : .parse_monolithic = shmem_parse_options,
3762 : .parse_param = shmem_parse_one,
3763 : .reconfigure = shmem_reconfigure,
3764 : #endif
3765 : };
3766 :
3767 : static struct kmem_cache *shmem_inode_cachep;
3768 :
3769 1744 : static struct inode *shmem_alloc_inode(struct super_block *sb)
3770 : {
3771 1744 : struct shmem_inode_info *info;
3772 1744 : info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
3773 1744 : if (!info)
3774 : return NULL;
3775 1744 : return &info->vfs_inode;
3776 : }
3777 :
3778 1162 : static void shmem_free_in_core_inode(struct inode *inode)
3779 : {
3780 1162 : if (S_ISLNK(inode->i_mode))
3781 23 : kfree(inode->i_link);
3782 1162 : kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
3783 1162 : }
3784 :
3785 1162 : static void shmem_destroy_inode(struct inode *inode)
3786 : {
3787 1162 : if (S_ISREG(inode->i_mode))
3788 586 : mpol_free_shared_policy(&SHMEM_I(inode)->policy);
3789 1162 : }
3790 :
3791 920 : static void shmem_init_inode(void *foo)
3792 : {
3793 920 : struct shmem_inode_info *info = foo;
3794 920 : inode_init_once(&info->vfs_inode);
3795 920 : }
3796 :
3797 1 : static void shmem_init_inodecache(void)
3798 : {
3799 1 : shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
3800 : sizeof(struct shmem_inode_info),
3801 : 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
3802 1 : }
3803 :
3804 0 : static void shmem_destroy_inodecache(void)
3805 : {
3806 0 : kmem_cache_destroy(shmem_inode_cachep);
3807 : }
3808 :
3809 : const struct address_space_operations shmem_aops = {
3810 : .writepage = shmem_writepage,
3811 : .set_page_dirty = __set_page_dirty_no_writeback,
3812 : #ifdef CONFIG_TMPFS
3813 : .write_begin = shmem_write_begin,
3814 : .write_end = shmem_write_end,
3815 : #endif
3816 : #ifdef CONFIG_MIGRATION
3817 : .migratepage = migrate_page,
3818 : #endif
3819 : .error_remove_page = generic_error_remove_page,
3820 : };
3821 : EXPORT_SYMBOL(shmem_aops);
3822 :
3823 : static const struct file_operations shmem_file_operations = {
3824 : .mmap = shmem_mmap,
3825 : .get_unmapped_area = shmem_get_unmapped_area,
3826 : #ifdef CONFIG_TMPFS
3827 : .llseek = shmem_file_llseek,
3828 : .read_iter = shmem_file_read_iter,
3829 : .write_iter = generic_file_write_iter,
3830 : .fsync = noop_fsync,
3831 : .splice_read = generic_file_splice_read,
3832 : .splice_write = iter_file_splice_write,
3833 : .fallocate = shmem_fallocate,
3834 : #endif
3835 : };
3836 :
3837 : static const struct inode_operations shmem_inode_operations = {
3838 : .getattr = shmem_getattr,
3839 : .setattr = shmem_setattr,
3840 : #ifdef CONFIG_TMPFS_XATTR
3841 : .listxattr = shmem_listxattr,
3842 : .set_acl = simple_set_acl,
3843 : #endif
3844 : };
3845 :
3846 : static const struct inode_operations shmem_dir_inode_operations = {
3847 : #ifdef CONFIG_TMPFS
3848 : .create = shmem_create,
3849 : .lookup = simple_lookup,
3850 : .link = shmem_link,
3851 : .unlink = shmem_unlink,
3852 : .symlink = shmem_symlink,
3853 : .mkdir = shmem_mkdir,
3854 : .rmdir = shmem_rmdir,
3855 : .mknod = shmem_mknod,
3856 : .rename = shmem_rename2,
3857 : .tmpfile = shmem_tmpfile,
3858 : #endif
3859 : #ifdef CONFIG_TMPFS_XATTR
3860 : .listxattr = shmem_listxattr,
3861 : #endif
3862 : #ifdef CONFIG_TMPFS_POSIX_ACL
3863 : .setattr = shmem_setattr,
3864 : .set_acl = simple_set_acl,
3865 : #endif
3866 : };
3867 :
3868 : static const struct inode_operations shmem_special_inode_operations = {
3869 : #ifdef CONFIG_TMPFS_XATTR
3870 : .listxattr = shmem_listxattr,
3871 : #endif
3872 : #ifdef CONFIG_TMPFS_POSIX_ACL
3873 : .setattr = shmem_setattr,
3874 : .set_acl = simple_set_acl,
3875 : #endif
3876 : };
3877 :
3878 : static const struct super_operations shmem_ops = {
3879 : .alloc_inode = shmem_alloc_inode,
3880 : .free_inode = shmem_free_in_core_inode,
3881 : .destroy_inode = shmem_destroy_inode,
3882 : #ifdef CONFIG_TMPFS
3883 : .statfs = shmem_statfs,
3884 : .show_options = shmem_show_options,
3885 : #endif
3886 : .evict_inode = shmem_evict_inode,
3887 : .drop_inode = generic_delete_inode,
3888 : .put_super = shmem_put_super,
3889 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3890 : .nr_cached_objects = shmem_unused_huge_count,
3891 : .free_cached_objects = shmem_unused_huge_scan,
3892 : #endif
3893 : };
3894 :
3895 : static const struct vm_operations_struct shmem_vm_ops = {
3896 : .fault = shmem_fault,
3897 : .map_pages = filemap_map_pages,
3898 : #ifdef CONFIG_NUMA
3899 : .set_policy = shmem_set_policy,
3900 : .get_policy = shmem_get_policy,
3901 : #endif
3902 : };
3903 :
3904 104 : int shmem_init_fs_context(struct fs_context *fc)
3905 : {
3906 104 : struct shmem_options *ctx;
3907 :
3908 104 : ctx = kzalloc(sizeof(struct shmem_options), GFP_KERNEL);
3909 104 : if (!ctx)
3910 : return -ENOMEM;
3911 :
3912 104 : ctx->mode = 0777 | S_ISVTX;
3913 104 : ctx->uid = current_fsuid();
3914 104 : ctx->gid = current_fsgid();
3915 :
3916 104 : fc->fs_private = ctx;
3917 104 : fc->ops = &shmem_fs_context_ops;
3918 104 : return 0;
3919 : }
3920 :
3921 : static struct file_system_type shmem_fs_type = {
3922 : .owner = THIS_MODULE,
3923 : .name = "tmpfs",
3924 : .init_fs_context = shmem_init_fs_context,
3925 : #ifdef CONFIG_TMPFS
3926 : .parameters = shmem_fs_parameters,
3927 : #endif
3928 : .kill_sb = kill_litter_super,
3929 : .fs_flags = FS_USERNS_MOUNT | FS_THP_SUPPORT,
3930 : };
3931 :
3932 1 : int __init shmem_init(void)
3933 : {
3934 1 : int error;
3935 :
3936 1 : shmem_init_inodecache();
3937 :
3938 1 : error = register_filesystem(&shmem_fs_type);
3939 1 : if (error) {
3940 0 : pr_err("Could not register tmpfs\n");
3941 0 : goto out2;
3942 : }
3943 :
3944 1 : shm_mnt = kern_mount(&shmem_fs_type);
3945 1 : if (IS_ERR(shm_mnt)) {
3946 0 : error = PTR_ERR(shm_mnt);
3947 0 : pr_err("Could not kern_mount tmpfs\n");
3948 0 : goto out1;
3949 : }
3950 :
3951 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3952 1 : if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
3953 1 : SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
3954 : else
3955 0 : shmem_huge = 0; /* just in case it was patched */
3956 : #endif
3957 : return 0;
3958 :
3959 0 : out1:
3960 0 : unregister_filesystem(&shmem_fs_type);
3961 0 : out2:
3962 0 : shmem_destroy_inodecache();
3963 0 : shm_mnt = ERR_PTR(error);
3964 0 : return error;
3965 : }
3966 :
3967 : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
3968 0 : static ssize_t shmem_enabled_show(struct kobject *kobj,
3969 : struct kobj_attribute *attr, char *buf)
3970 : {
3971 0 : static const int values[] = {
3972 : SHMEM_HUGE_ALWAYS,
3973 : SHMEM_HUGE_WITHIN_SIZE,
3974 : SHMEM_HUGE_ADVISE,
3975 : SHMEM_HUGE_NEVER,
3976 : SHMEM_HUGE_DENY,
3977 : SHMEM_HUGE_FORCE,
3978 : };
3979 0 : int len = 0;
3980 0 : int i;
3981 :
3982 0 : for (i = 0; i < ARRAY_SIZE(values); i++) {
3983 0 : len += sysfs_emit_at(buf, len,
3984 0 : shmem_huge == values[i] ? "%s[%s]" : "%s%s",
3985 : i ? " " : "",
3986 : shmem_format_huge(values[i]));
3987 : }
3988 :
3989 0 : len += sysfs_emit_at(buf, len, "\n");
3990 :
3991 0 : return len;
3992 : }
3993 :
3994 0 : static ssize_t shmem_enabled_store(struct kobject *kobj,
3995 : struct kobj_attribute *attr, const char *buf, size_t count)
3996 : {
3997 0 : char tmp[16];
3998 0 : int huge;
3999 :
4000 0 : if (count + 1 > sizeof(tmp))
4001 : return -EINVAL;
4002 0 : memcpy(tmp, buf, count);
4003 0 : tmp[count] = '\0';
4004 0 : if (count && tmp[count - 1] == '\n')
4005 0 : tmp[count - 1] = '\0';
4006 :
4007 0 : huge = shmem_parse_huge(tmp);
4008 0 : if (huge == -EINVAL)
4009 : return -EINVAL;
4010 0 : if (!has_transparent_hugepage() &&
4011 : huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
4012 : return -EINVAL;
4013 :
4014 0 : shmem_huge = huge;
4015 0 : if (shmem_huge > SHMEM_HUGE_DENY)
4016 0 : SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
4017 0 : return count;
4018 : }
4019 :
4020 : struct kobj_attribute shmem_enabled_attr =
4021 : __ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store);
4022 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */
4023 :
4024 : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4025 9 : bool shmem_huge_enabled(struct vm_area_struct *vma)
4026 : {
4027 9 : struct inode *inode = file_inode(vma->vm_file);
4028 9 : struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
4029 9 : loff_t i_size;
4030 9 : pgoff_t off;
4031 :
4032 9 : if ((vma->vm_flags & VM_NOHUGEPAGE) ||
4033 9 : test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
4034 0 : return false;
4035 9 : if (shmem_huge == SHMEM_HUGE_FORCE)
4036 : return true;
4037 9 : if (shmem_huge == SHMEM_HUGE_DENY)
4038 : return false;
4039 9 : switch (sbinfo->huge) {
4040 : case SHMEM_HUGE_NEVER:
4041 : return false;
4042 0 : case SHMEM_HUGE_ALWAYS:
4043 0 : return true;
4044 0 : case SHMEM_HUGE_WITHIN_SIZE:
4045 0 : off = round_up(vma->vm_pgoff, HPAGE_PMD_NR);
4046 0 : i_size = round_up(i_size_read(inode), PAGE_SIZE);
4047 0 : if (i_size >= HPAGE_PMD_SIZE &&
4048 0 : i_size >> PAGE_SHIFT >= off)
4049 : return true;
4050 0 : fallthrough;
4051 : case SHMEM_HUGE_ADVISE:
4052 : /* TODO: implement fadvise() hints */
4053 0 : return (vma->vm_flags & VM_HUGEPAGE);
4054 : default:
4055 0 : VM_BUG_ON(1);
4056 : return false;
4057 : }
4058 : }
4059 : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
4060 :
4061 : #else /* !CONFIG_SHMEM */
4062 :
4063 : /*
4064 : * tiny-shmem: simple shmemfs and tmpfs using ramfs code
4065 : *
4066 : * This is intended for small system where the benefits of the full
4067 : * shmem code (swap-backed and resource-limited) are outweighed by
4068 : * their complexity. On systems without swap this code should be
4069 : * effectively equivalent, but much lighter weight.
4070 : */
4071 :
4072 : static struct file_system_type shmem_fs_type = {
4073 : .name = "tmpfs",
4074 : .init_fs_context = ramfs_init_fs_context,
4075 : .parameters = ramfs_fs_parameters,
4076 : .kill_sb = kill_litter_super,
4077 : .fs_flags = FS_USERNS_MOUNT,
4078 : };
4079 :
4080 : int __init shmem_init(void)
4081 : {
4082 : BUG_ON(register_filesystem(&shmem_fs_type) != 0);
4083 :
4084 : shm_mnt = kern_mount(&shmem_fs_type);
4085 : BUG_ON(IS_ERR(shm_mnt));
4086 :
4087 : return 0;
4088 : }
4089 :
4090 : int shmem_unuse(unsigned int type, bool frontswap,
4091 : unsigned long *fs_pages_to_unuse)
4092 : {
4093 : return 0;
4094 : }
4095 :
4096 : int shmem_lock(struct file *file, int lock, struct user_struct *user)
4097 : {
4098 : return 0;
4099 : }
4100 :
4101 : void shmem_unlock_mapping(struct address_space *mapping)
4102 : {
4103 : }
4104 :
4105 : #ifdef CONFIG_MMU
4106 : unsigned long shmem_get_unmapped_area(struct file *file,
4107 : unsigned long addr, unsigned long len,
4108 : unsigned long pgoff, unsigned long flags)
4109 : {
4110 : return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
4111 : }
4112 : #endif
4113 :
4114 : void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
4115 : {
4116 : truncate_inode_pages_range(inode->i_mapping, lstart, lend);
4117 : }
4118 : EXPORT_SYMBOL_GPL(shmem_truncate_range);
4119 :
4120 : #define shmem_vm_ops generic_file_vm_ops
4121 : #define shmem_file_operations ramfs_file_operations
4122 : #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
4123 : #define shmem_acct_size(flags, size) 0
4124 : #define shmem_unacct_size(flags, size) do {} while (0)
4125 :
4126 : #endif /* CONFIG_SHMEM */
4127 :
4128 : /* common code */
4129 :
4130 6 : static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, loff_t size,
4131 : unsigned long flags, unsigned int i_flags)
4132 : {
4133 6 : struct inode *inode;
4134 6 : struct file *res;
4135 :
4136 6 : if (IS_ERR(mnt))
4137 6 : return ERR_CAST(mnt);
4138 :
4139 6 : if (size < 0 || size > MAX_LFS_FILESIZE)
4140 6 : return ERR_PTR(-EINVAL);
4141 :
4142 6 : if (shmem_acct_size(flags, size))
4143 6 : return ERR_PTR(-ENOMEM);
4144 :
4145 6 : inode = shmem_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0,
4146 : flags);
4147 6 : if (unlikely(!inode)) {
4148 0 : shmem_unacct_size(flags, size);
4149 0 : return ERR_PTR(-ENOSPC);
4150 : }
4151 6 : inode->i_flags |= i_flags;
4152 6 : inode->i_size = size;
4153 6 : clear_nlink(inode); /* It is unlinked */
4154 6 : res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
4155 6 : if (!IS_ERR(res))
4156 6 : res = alloc_file_pseudo(inode, mnt, name, O_RDWR,
4157 : &shmem_file_operations);
4158 6 : if (IS_ERR(res))
4159 0 : iput(inode);
4160 : return res;
4161 : }
4162 :
4163 : /**
4164 : * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
4165 : * kernel internal. There will be NO LSM permission checks against the
4166 : * underlying inode. So users of this interface must do LSM checks at a
4167 : * higher layer. The users are the big_key and shm implementations. LSM
4168 : * checks are provided at the key or shm level rather than the inode.
4169 : * @name: name for dentry (to be seen in /proc/<pid>/maps
4170 : * @size: size to be set for the file
4171 : * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4172 : */
4173 3 : struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags)
4174 : {
4175 0 : return __shmem_file_setup(shm_mnt, name, size, flags, S_PRIVATE);
4176 : }
4177 :
4178 : /**
4179 : * shmem_file_setup - get an unlinked file living in tmpfs
4180 : * @name: name for dentry (to be seen in /proc/<pid>/maps
4181 : * @size: size to be set for the file
4182 : * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4183 : */
4184 3 : struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags)
4185 : {
4186 3 : return __shmem_file_setup(shm_mnt, name, size, flags, 0);
4187 : }
4188 : EXPORT_SYMBOL_GPL(shmem_file_setup);
4189 :
4190 : /**
4191 : * shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
4192 : * @mnt: the tmpfs mount where the file will be created
4193 : * @name: name for dentry (to be seen in /proc/<pid>/maps
4194 : * @size: size to be set for the file
4195 : * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4196 : */
4197 0 : struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, const char *name,
4198 : loff_t size, unsigned long flags)
4199 : {
4200 0 : return __shmem_file_setup(mnt, name, size, flags, 0);
4201 : }
4202 : EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt);
4203 :
4204 : /**
4205 : * shmem_zero_setup - setup a shared anonymous mapping
4206 : * @vma: the vma to be mmapped is prepared by do_mmap
4207 : */
4208 3 : int shmem_zero_setup(struct vm_area_struct *vma)
4209 : {
4210 3 : struct file *file;
4211 3 : loff_t size = vma->vm_end - vma->vm_start;
4212 :
4213 : /*
4214 : * Cloning a new file under mmap_lock leads to a lock ordering conflict
4215 : * between XFS directory reading and selinux: since this file is only
4216 : * accessible to the user through its mapping, use S_PRIVATE flag to
4217 : * bypass file security, in the same way as shmem_kernel_file_setup().
4218 : */
4219 3 : file = shmem_kernel_file_setup("dev/zero", size, vma->vm_flags);
4220 3 : if (IS_ERR(file))
4221 0 : return PTR_ERR(file);
4222 :
4223 3 : if (vma->vm_file)
4224 0 : fput(vma->vm_file);
4225 3 : vma->vm_file = file;
4226 3 : vma->vm_ops = &shmem_vm_ops;
4227 :
4228 3 : if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
4229 3 : ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
4230 3 : (vma->vm_end & HPAGE_PMD_MASK)) {
4231 0 : khugepaged_enter(vma, vma->vm_flags);
4232 : }
4233 :
4234 : return 0;
4235 : }
4236 :
4237 : /**
4238 : * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
4239 : * @mapping: the page's address_space
4240 : * @index: the page index
4241 : * @gfp: the page allocator flags to use if allocating
4242 : *
4243 : * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
4244 : * with any new page allocations done using the specified allocation flags.
4245 : * But read_cache_page_gfp() uses the ->readpage() method: which does not
4246 : * suit tmpfs, since it may have pages in swapcache, and needs to find those
4247 : * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
4248 : *
4249 : * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
4250 : * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
4251 : */
4252 0 : struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
4253 : pgoff_t index, gfp_t gfp)
4254 : {
4255 : #ifdef CONFIG_SHMEM
4256 0 : struct inode *inode = mapping->host;
4257 0 : struct page *page;
4258 0 : int error;
4259 :
4260 0 : BUG_ON(!shmem_mapping(mapping));
4261 0 : error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE,
4262 : gfp, NULL, NULL, NULL);
4263 0 : if (error)
4264 0 : page = ERR_PTR(error);
4265 : else
4266 0 : unlock_page(page);
4267 0 : return page;
4268 : #else
4269 : /*
4270 : * The tiny !SHMEM case uses ramfs without swap
4271 : */
4272 : return read_cache_page_gfp(mapping, index, gfp);
4273 : #endif
4274 : }
4275 : EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp);
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