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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
40#include <asm/tlbflush.h>
41
42static struct vfsmount *shm_mnt;
43
44#ifdef CONFIG_SHMEM
45
46
47
48
49
50
51#include <linux/xattr.h>
52#include <linux/exportfs.h>
53#include <linux/posix_acl.h>
54#include <linux/posix_acl_xattr.h>
55#include <linux/mman.h>
56#include <linux/string.h>
57#include <linux/slab.h>
58#include <linux/backing-dev.h>
59#include <linux/shmem_fs.h>
60#include <linux/writeback.h>
61#include <linux/blkdev.h>
62#include <linux/pagevec.h>
63#include <linux/percpu_counter.h>
64#include <linux/falloc.h>
65#include <linux/splice.h>
66#include <linux/security.h>
67#include <linux/swapops.h>
68#include <linux/mempolicy.h>
69#include <linux/namei.h>
70#include <linux/ctype.h>
71#include <linux/migrate.h>
72#include <linux/highmem.h>
73#include <linux/seq_file.h>
74#include <linux/magic.h>
75#include <linux/syscalls.h>
76#include <linux/fcntl.h>
77#include <uapi/linux/memfd.h>
78#include <linux/userfaultfd_k.h>
79#include <linux/rmap.h>
80#include <linux/uuid.h>
81
82#include <linux/uaccess.h>
83#include <asm/pgtable.h>
84
85#include "internal.h"
86
87#define BLOCKS_PER_PAGE (PAGE_SIZE/512)
88#define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
89
90
91#define BOGO_DIRENT_SIZE 20
92
93
94#define SHORT_SYMLINK_LEN 128
95
96
97
98
99
100
101struct shmem_falloc {
102 wait_queue_head_t *waitq;
103 pgoff_t start;
104 pgoff_t next;
105 pgoff_t nr_falloced;
106 pgoff_t nr_unswapped;
107};
108
109#ifdef CONFIG_TMPFS
110static unsigned long shmem_default_max_blocks(void)
111{
112 return totalram_pages() / 2;
113}
114
115static unsigned long shmem_default_max_inodes(void)
116{
117 unsigned long nr_pages = totalram_pages();
118
119 return min(nr_pages - totalhigh_pages(), nr_pages / 2);
120}
121#endif
122
123static bool shmem_should_replace_page(struct page *page, gfp_t gfp);
124static int shmem_replace_page(struct page **pagep, gfp_t gfp,
125 struct shmem_inode_info *info, pgoff_t index);
126static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
127 struct page **pagep, enum sgp_type sgp,
128 gfp_t gfp, struct vm_area_struct *vma,
129 struct vm_fault *vmf, vm_fault_t *fault_type);
130
131int shmem_getpage(struct inode *inode, pgoff_t index,
132 struct page **pagep, enum sgp_type sgp)
133{
134 return shmem_getpage_gfp(inode, index, pagep, sgp,
135 mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL);
136}
137
138static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
139{
140 return sb->s_fs_info;
141}
142
143
144
145
146
147
148
149static inline int shmem_acct_size(unsigned long flags, loff_t size)
150{
151 return (flags & VM_NORESERVE) ?
152 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size));
153}
154
155static inline void shmem_unacct_size(unsigned long flags, loff_t size)
156{
157 if (!(flags & VM_NORESERVE))
158 vm_unacct_memory(VM_ACCT(size));
159}
160
161static inline int shmem_reacct_size(unsigned long flags,
162 loff_t oldsize, loff_t newsize)
163{
164 if (!(flags & VM_NORESERVE)) {
165 if (VM_ACCT(newsize) > VM_ACCT(oldsize))
166 return security_vm_enough_memory_mm(current->mm,
167 VM_ACCT(newsize) - VM_ACCT(oldsize));
168 else if (VM_ACCT(newsize) < VM_ACCT(oldsize))
169 vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize));
170 }
171 return 0;
172}
173
174
175
176
177
178
179
180static inline int shmem_acct_block(unsigned long flags, long pages)
181{
182 if (!(flags & VM_NORESERVE))
183 return 0;
184
185 return security_vm_enough_memory_mm(current->mm,
186 pages * VM_ACCT(PAGE_SIZE));
187}
188
189static inline void shmem_unacct_blocks(unsigned long flags, long pages)
190{
191 if (flags & VM_NORESERVE)
192 vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));
193}
194
195static inline bool shmem_inode_acct_block(struct inode *inode, long pages)
196{
197 struct shmem_inode_info *info = SHMEM_I(inode);
198 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
199
200 if (shmem_acct_block(info->flags, pages))
201 return false;
202
203 if (sbinfo->max_blocks) {
204 if (percpu_counter_compare(&sbinfo->used_blocks,
205 sbinfo->max_blocks - pages) > 0)
206 goto unacct;
207 percpu_counter_add(&sbinfo->used_blocks, pages);
208 }
209
210 return true;
211
212unacct:
213 shmem_unacct_blocks(info->flags, pages);
214 return false;
215}
216
217static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages)
218{
219 struct shmem_inode_info *info = SHMEM_I(inode);
220 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
221
222 if (sbinfo->max_blocks)
223 percpu_counter_sub(&sbinfo->used_blocks, pages);
224 shmem_unacct_blocks(info->flags, pages);
225}
226
227static const struct super_operations shmem_ops;
228static const struct address_space_operations shmem_aops;
229static const struct file_operations shmem_file_operations;
230static const struct inode_operations shmem_inode_operations;
231static const struct inode_operations shmem_dir_inode_operations;
232static const struct inode_operations shmem_special_inode_operations;
233static const struct vm_operations_struct shmem_vm_ops;
234static struct file_system_type shmem_fs_type;
235
236bool vma_is_shmem(struct vm_area_struct *vma)
237{
238 return vma->vm_ops == &shmem_vm_ops;
239}
240
241static LIST_HEAD(shmem_swaplist);
242static DEFINE_MUTEX(shmem_swaplist_mutex);
243
244static int shmem_reserve_inode(struct super_block *sb)
245{
246 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
247 if (sbinfo->max_inodes) {
248 spin_lock(&sbinfo->stat_lock);
249 if (!sbinfo->free_inodes) {
250 spin_unlock(&sbinfo->stat_lock);
251 return -ENOSPC;
252 }
253 sbinfo->free_inodes--;
254 spin_unlock(&sbinfo->stat_lock);
255 }
256 return 0;
257}
258
259static void shmem_free_inode(struct super_block *sb)
260{
261 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
262 if (sbinfo->max_inodes) {
263 spin_lock(&sbinfo->stat_lock);
264 sbinfo->free_inodes++;
265 spin_unlock(&sbinfo->stat_lock);
266 }
267}
268
269
270
271
272
273
274
275
276
277
278
279
280
281static void shmem_recalc_inode(struct inode *inode)
282{
283 struct shmem_inode_info *info = SHMEM_I(inode);
284 long freed;
285
286 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
287 if (freed > 0) {
288 info->alloced -= freed;
289 inode->i_blocks -= freed * BLOCKS_PER_PAGE;
290 shmem_inode_unacct_blocks(inode, freed);
291 }
292}
293
294bool shmem_charge(struct inode *inode, long pages)
295{
296 struct shmem_inode_info *info = SHMEM_I(inode);
297 unsigned long flags;
298
299 if (!shmem_inode_acct_block(inode, pages))
300 return false;
301
302
303 inode->i_mapping->nrpages += pages;
304
305 spin_lock_irqsave(&info->lock, flags);
306 info->alloced += pages;
307 inode->i_blocks += pages * BLOCKS_PER_PAGE;
308 shmem_recalc_inode(inode);
309 spin_unlock_irqrestore(&info->lock, flags);
310
311 return true;
312}
313
314void shmem_uncharge(struct inode *inode, long pages)
315{
316 struct shmem_inode_info *info = SHMEM_I(inode);
317 unsigned long flags;
318
319
320
321 spin_lock_irqsave(&info->lock, flags);
322 info->alloced -= pages;
323 inode->i_blocks -= pages * BLOCKS_PER_PAGE;
324 shmem_recalc_inode(inode);
325 spin_unlock_irqrestore(&info->lock, flags);
326
327 shmem_inode_unacct_blocks(inode, pages);
328}
329
330
331
332
333static int shmem_replace_entry(struct address_space *mapping,
334 pgoff_t index, void *expected, void *replacement)
335{
336 XA_STATE(xas, &mapping->i_pages, index);
337 void *item;
338
339 VM_BUG_ON(!expected);
340 VM_BUG_ON(!replacement);
341 item = xas_load(&xas);
342 if (item != expected)
343 return -ENOENT;
344 xas_store(&xas, replacement);
345 return 0;
346}
347
348
349
350
351
352
353
354
355static bool shmem_confirm_swap(struct address_space *mapping,
356 pgoff_t index, swp_entry_t swap)
357{
358 return xa_load(&mapping->i_pages, index) == swp_to_radix_entry(swap);
359}
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375#define SHMEM_HUGE_NEVER 0
376#define SHMEM_HUGE_ALWAYS 1
377#define SHMEM_HUGE_WITHIN_SIZE 2
378#define SHMEM_HUGE_ADVISE 3
379
380
381
382
383
384
385
386
387
388
389
390#define SHMEM_HUGE_DENY (-1)
391#define SHMEM_HUGE_FORCE (-2)
392
393#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
394
395
396static int shmem_huge __read_mostly;
397
398#if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
399static int shmem_parse_huge(const char *str)
400{
401 if (!strcmp(str, "never"))
402 return SHMEM_HUGE_NEVER;
403 if (!strcmp(str, "always"))
404 return SHMEM_HUGE_ALWAYS;
405 if (!strcmp(str, "within_size"))
406 return SHMEM_HUGE_WITHIN_SIZE;
407 if (!strcmp(str, "advise"))
408 return SHMEM_HUGE_ADVISE;
409 if (!strcmp(str, "deny"))
410 return SHMEM_HUGE_DENY;
411 if (!strcmp(str, "force"))
412 return SHMEM_HUGE_FORCE;
413 return -EINVAL;
414}
415
416static const char *shmem_format_huge(int huge)
417{
418 switch (huge) {
419 case SHMEM_HUGE_NEVER:
420 return "never";
421 case SHMEM_HUGE_ALWAYS:
422 return "always";
423 case SHMEM_HUGE_WITHIN_SIZE:
424 return "within_size";
425 case SHMEM_HUGE_ADVISE:
426 return "advise";
427 case SHMEM_HUGE_DENY:
428 return "deny";
429 case SHMEM_HUGE_FORCE:
430 return "force";
431 default:
432 VM_BUG_ON(1);
433 return "bad_val";
434 }
435}
436#endif
437
438static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
439 struct shrink_control *sc, unsigned long nr_to_split)
440{
441 LIST_HEAD(list), *pos, *next;
442 LIST_HEAD(to_remove);
443 struct inode *inode;
444 struct shmem_inode_info *info;
445 struct page *page;
446 unsigned long batch = sc ? sc->nr_to_scan : 128;
447 int removed = 0, split = 0;
448
449 if (list_empty(&sbinfo->shrinklist))
450 return SHRINK_STOP;
451
452 spin_lock(&sbinfo->shrinklist_lock);
453 list_for_each_safe(pos, next, &sbinfo->shrinklist) {
454 info = list_entry(pos, struct shmem_inode_info, shrinklist);
455
456
457 inode = igrab(&info->vfs_inode);
458
459
460 if (!inode) {
461 list_del_init(&info->shrinklist);
462 removed++;
463 goto next;
464 }
465
466
467 if (round_up(inode->i_size, PAGE_SIZE) ==
468 round_up(inode->i_size, HPAGE_PMD_SIZE)) {
469 list_move(&info->shrinklist, &to_remove);
470 removed++;
471 goto next;
472 }
473
474 list_move(&info->shrinklist, &list);
475next:
476 if (!--batch)
477 break;
478 }
479 spin_unlock(&sbinfo->shrinklist_lock);
480
481 list_for_each_safe(pos, next, &to_remove) {
482 info = list_entry(pos, struct shmem_inode_info, shrinklist);
483 inode = &info->vfs_inode;
484 list_del_init(&info->shrinklist);
485 iput(inode);
486 }
487
488 list_for_each_safe(pos, next, &list) {
489 int ret;
490
491 info = list_entry(pos, struct shmem_inode_info, shrinklist);
492 inode = &info->vfs_inode;
493
494 if (nr_to_split && split >= nr_to_split)
495 goto leave;
496
497 page = find_get_page(inode->i_mapping,
498 (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT);
499 if (!page)
500 goto drop;
501
502
503 if (!PageTransHuge(page)) {
504 put_page(page);
505 goto drop;
506 }
507
508
509
510
511
512
513
514
515 if (!trylock_page(page)) {
516 put_page(page);
517 goto leave;
518 }
519
520 ret = split_huge_page(page);
521 unlock_page(page);
522 put_page(page);
523
524
525 if (ret)
526 goto leave;
527
528 split++;
529drop:
530 list_del_init(&info->shrinklist);
531 removed++;
532leave:
533 iput(inode);
534 }
535
536 spin_lock(&sbinfo->shrinklist_lock);
537 list_splice_tail(&list, &sbinfo->shrinklist);
538 sbinfo->shrinklist_len -= removed;
539 spin_unlock(&sbinfo->shrinklist_lock);
540
541 return split;
542}
543
544static long shmem_unused_huge_scan(struct super_block *sb,
545 struct shrink_control *sc)
546{
547 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
548
549 if (!READ_ONCE(sbinfo->shrinklist_len))
550 return SHRINK_STOP;
551
552 return shmem_unused_huge_shrink(sbinfo, sc, 0);
553}
554
555static long shmem_unused_huge_count(struct super_block *sb,
556 struct shrink_control *sc)
557{
558 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
559 return READ_ONCE(sbinfo->shrinklist_len);
560}
561#else
562
563#define shmem_huge SHMEM_HUGE_DENY
564
565static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
566 struct shrink_control *sc, unsigned long nr_to_split)
567{
568 return 0;
569}
570#endif
571
572static inline bool is_huge_enabled(struct shmem_sb_info *sbinfo)
573{
574 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
575 (shmem_huge == SHMEM_HUGE_FORCE || sbinfo->huge) &&
576 shmem_huge != SHMEM_HUGE_DENY)
577 return true;
578 return false;
579}
580
581
582
583
584static int shmem_add_to_page_cache(struct page *page,
585 struct address_space *mapping,
586 pgoff_t index, void *expected, gfp_t gfp)
587{
588 XA_STATE_ORDER(xas, &mapping->i_pages, index, compound_order(page));
589 unsigned long i = 0;
590 unsigned long nr = 1UL << compound_order(page);
591
592 VM_BUG_ON_PAGE(PageTail(page), page);
593 VM_BUG_ON_PAGE(index != round_down(index, nr), page);
594 VM_BUG_ON_PAGE(!PageLocked(page), page);
595 VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
596 VM_BUG_ON(expected && PageTransHuge(page));
597
598 page_ref_add(page, nr);
599 page->mapping = mapping;
600 page->index = index;
601
602 do {
603 void *entry;
604 xas_lock_irq(&xas);
605 entry = xas_find_conflict(&xas);
606 if (entry != expected)
607 xas_set_err(&xas, -EEXIST);
608 xas_create_range(&xas);
609 if (xas_error(&xas))
610 goto unlock;
611next:
612 xas_store(&xas, page + i);
613 if (++i < nr) {
614 xas_next(&xas);
615 goto next;
616 }
617 if (PageTransHuge(page)) {
618 count_vm_event(THP_FILE_ALLOC);
619 __inc_node_page_state(page, NR_SHMEM_THPS);
620 }
621 mapping->nrpages += nr;
622 __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr);
623 __mod_node_page_state(page_pgdat(page), NR_SHMEM, nr);
624unlock:
625 xas_unlock_irq(&xas);
626 } while (xas_nomem(&xas, gfp));
627
628 if (xas_error(&xas)) {
629 page->mapping = NULL;
630 page_ref_sub(page, nr);
631 return xas_error(&xas);
632 }
633
634 return 0;
635}
636
637
638
639
640static void shmem_delete_from_page_cache(struct page *page, void *radswap)
641{
642 struct address_space *mapping = page->mapping;
643 int error;
644
645 VM_BUG_ON_PAGE(PageCompound(page), page);
646
647 xa_lock_irq(&mapping->i_pages);
648 error = shmem_replace_entry(mapping, page->index, page, radswap);
649 page->mapping = NULL;
650 mapping->nrpages--;
651 __dec_node_page_state(page, NR_FILE_PAGES);
652 __dec_node_page_state(page, NR_SHMEM);
653 xa_unlock_irq(&mapping->i_pages);
654 put_page(page);
655 BUG_ON(error);
656}
657
658
659
660
661static int shmem_free_swap(struct address_space *mapping,
662 pgoff_t index, void *radswap)
663{
664 void *old;
665
666 old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0);
667 if (old != radswap)
668 return -ENOENT;
669 free_swap_and_cache(radix_to_swp_entry(radswap));
670 return 0;
671}
672
673
674
675
676
677
678
679
680unsigned long shmem_partial_swap_usage(struct address_space *mapping,
681 pgoff_t start, pgoff_t end)
682{
683 XA_STATE(xas, &mapping->i_pages, start);
684 struct page *page;
685 unsigned long swapped = 0;
686
687 rcu_read_lock();
688 xas_for_each(&xas, page, end - 1) {
689 if (xas_retry(&xas, page))
690 continue;
691 if (xa_is_value(page))
692 swapped++;
693
694 if (need_resched()) {
695 xas_pause(&xas);
696 cond_resched_rcu();
697 }
698 }
699
700 rcu_read_unlock();
701
702 return swapped << PAGE_SHIFT;
703}
704
705
706
707
708
709
710
711
712unsigned long shmem_swap_usage(struct vm_area_struct *vma)
713{
714 struct inode *inode = file_inode(vma->vm_file);
715 struct shmem_inode_info *info = SHMEM_I(inode);
716 struct address_space *mapping = inode->i_mapping;
717 unsigned long swapped;
718
719
720 swapped = READ_ONCE(info->swapped);
721
722
723
724
725
726
727 if (!swapped)
728 return 0;
729
730 if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size)
731 return swapped << PAGE_SHIFT;
732
733
734 return shmem_partial_swap_usage(mapping,
735 linear_page_index(vma, vma->vm_start),
736 linear_page_index(vma, vma->vm_end));
737}
738
739
740
741
742void shmem_unlock_mapping(struct address_space *mapping)
743{
744 struct pagevec pvec;
745 pgoff_t indices[PAGEVEC_SIZE];
746 pgoff_t index = 0;
747
748 pagevec_init(&pvec);
749
750
751
752 while (!mapping_unevictable(mapping)) {
753
754
755
756
757 pvec.nr = find_get_entries(mapping, index,
758 PAGEVEC_SIZE, pvec.pages, indices);
759 if (!pvec.nr)
760 break;
761 index = indices[pvec.nr - 1] + 1;
762 pagevec_remove_exceptionals(&pvec);
763 check_move_unevictable_pages(&pvec);
764 pagevec_release(&pvec);
765 cond_resched();
766 }
767}
768
769
770
771
772
773static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
774 bool unfalloc)
775{
776 struct address_space *mapping = inode->i_mapping;
777 struct shmem_inode_info *info = SHMEM_I(inode);
778 pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
779 pgoff_t end = (lend + 1) >> PAGE_SHIFT;
780 unsigned int partial_start = lstart & (PAGE_SIZE - 1);
781 unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1);
782 struct pagevec pvec;
783 pgoff_t indices[PAGEVEC_SIZE];
784 long nr_swaps_freed = 0;
785 pgoff_t index;
786 int i;
787
788 if (lend == -1)
789 end = -1;
790
791 pagevec_init(&pvec);
792 index = start;
793 while (index < end) {
794 pvec.nr = find_get_entries(mapping, index,
795 min(end - index, (pgoff_t)PAGEVEC_SIZE),
796 pvec.pages, indices);
797 if (!pvec.nr)
798 break;
799 for (i = 0; i < pagevec_count(&pvec); i++) {
800 struct page *page = pvec.pages[i];
801
802 index = indices[i];
803 if (index >= end)
804 break;
805
806 if (xa_is_value(page)) {
807 if (unfalloc)
808 continue;
809 nr_swaps_freed += !shmem_free_swap(mapping,
810 index, page);
811 continue;
812 }
813
814 VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page);
815
816 if (!trylock_page(page))
817 continue;
818
819 if (PageTransTail(page)) {
820
821 clear_highpage(page);
822 unlock_page(page);
823 continue;
824 } else if (PageTransHuge(page)) {
825 if (index == round_down(end, HPAGE_PMD_NR)) {
826
827
828
829
830 clear_highpage(page);
831 unlock_page(page);
832 continue;
833 }
834 index += HPAGE_PMD_NR - 1;
835 i += HPAGE_PMD_NR - 1;
836 }
837
838 if (!unfalloc || !PageUptodate(page)) {
839 VM_BUG_ON_PAGE(PageTail(page), page);
840 if (page_mapping(page) == mapping) {
841 VM_BUG_ON_PAGE(PageWriteback(page), page);
842 truncate_inode_page(mapping, page);
843 }
844 }
845 unlock_page(page);
846 }
847 pagevec_remove_exceptionals(&pvec);
848 pagevec_release(&pvec);
849 cond_resched();
850 index++;
851 }
852
853 if (partial_start) {
854 struct page *page = NULL;
855 shmem_getpage(inode, start - 1, &page, SGP_READ);
856 if (page) {
857 unsigned int top = PAGE_SIZE;
858 if (start > end) {
859 top = partial_end;
860 partial_end = 0;
861 }
862 zero_user_segment(page, partial_start, top);
863 set_page_dirty(page);
864 unlock_page(page);
865 put_page(page);
866 }
867 }
868 if (partial_end) {
869 struct page *page = NULL;
870 shmem_getpage(inode, end, &page, SGP_READ);
871 if (page) {
872 zero_user_segment(page, 0, partial_end);
873 set_page_dirty(page);
874 unlock_page(page);
875 put_page(page);
876 }
877 }
878 if (start >= end)
879 return;
880
881 index = start;
882 while (index < end) {
883 cond_resched();
884
885 pvec.nr = find_get_entries(mapping, index,
886 min(end - index, (pgoff_t)PAGEVEC_SIZE),
887 pvec.pages, indices);
888 if (!pvec.nr) {
889
890 if (index == start || end != -1)
891 break;
892
893 index = start;
894 continue;
895 }
896 for (i = 0; i < pagevec_count(&pvec); i++) {
897 struct page *page = pvec.pages[i];
898
899 index = indices[i];
900 if (index >= end)
901 break;
902
903 if (xa_is_value(page)) {
904 if (unfalloc)
905 continue;
906 if (shmem_free_swap(mapping, index, page)) {
907
908 index--;
909 break;
910 }
911 nr_swaps_freed++;
912 continue;
913 }
914
915 lock_page(page);
916
917 if (PageTransTail(page)) {
918
919 clear_highpage(page);
920 unlock_page(page);
921
922
923
924
925
926 if (index != round_down(end, HPAGE_PMD_NR))
927 start++;
928 continue;
929 } else if (PageTransHuge(page)) {
930 if (index == round_down(end, HPAGE_PMD_NR)) {
931
932
933
934
935 clear_highpage(page);
936 unlock_page(page);
937 continue;
938 }
939 index += HPAGE_PMD_NR - 1;
940 i += HPAGE_PMD_NR - 1;
941 }
942
943 if (!unfalloc || !PageUptodate(page)) {
944 VM_BUG_ON_PAGE(PageTail(page), page);
945 if (page_mapping(page) == mapping) {
946 VM_BUG_ON_PAGE(PageWriteback(page), page);
947 truncate_inode_page(mapping, page);
948 } else {
949
950 unlock_page(page);
951 index--;
952 break;
953 }
954 }
955 unlock_page(page);
956 }
957 pagevec_remove_exceptionals(&pvec);
958 pagevec_release(&pvec);
959 index++;
960 }
961
962 spin_lock_irq(&info->lock);
963 info->swapped -= nr_swaps_freed;
964 shmem_recalc_inode(inode);
965 spin_unlock_irq(&info->lock);
966}
967
968void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
969{
970 shmem_undo_range(inode, lstart, lend, false);
971 inode->i_ctime = inode->i_mtime = current_time(inode);
972}
973EXPORT_SYMBOL_GPL(shmem_truncate_range);
974
975static int shmem_getattr(const struct path *path, struct kstat *stat,
976 u32 request_mask, unsigned int query_flags)
977{
978 struct inode *inode = path->dentry->d_inode;
979 struct shmem_inode_info *info = SHMEM_I(inode);
980 struct shmem_sb_info *sb_info = SHMEM_SB(inode->i_sb);
981
982 if (info->alloced - info->swapped != inode->i_mapping->nrpages) {
983 spin_lock_irq(&info->lock);
984 shmem_recalc_inode(inode);
985 spin_unlock_irq(&info->lock);
986 }
987 generic_fillattr(inode, stat);
988
989 if (is_huge_enabled(sb_info))
990 stat->blksize = HPAGE_PMD_SIZE;
991
992 return 0;
993}
994
995static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
996{
997 struct inode *inode = d_inode(dentry);
998 struct shmem_inode_info *info = SHMEM_I(inode);
999 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1000 int error;
1001
1002 error = setattr_prepare(dentry, attr);
1003 if (error)
1004 return error;
1005
1006 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
1007 loff_t oldsize = inode->i_size;
1008 loff_t newsize = attr->ia_size;
1009
1010
1011 if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
1012 (newsize > oldsize && (info->seals & F_SEAL_GROW)))
1013 return -EPERM;
1014
1015 if (newsize != oldsize) {
1016 error = shmem_reacct_size(SHMEM_I(inode)->flags,
1017 oldsize, newsize);
1018 if (error)
1019 return error;
1020 i_size_write(inode, newsize);
1021 inode->i_ctime = inode->i_mtime = current_time(inode);
1022 }
1023 if (newsize <= oldsize) {
1024 loff_t holebegin = round_up(newsize, PAGE_SIZE);
1025 if (oldsize > holebegin)
1026 unmap_mapping_range(inode->i_mapping,
1027 holebegin, 0, 1);
1028 if (info->alloced)
1029 shmem_truncate_range(inode,
1030 newsize, (loff_t)-1);
1031
1032 if (oldsize > holebegin)
1033 unmap_mapping_range(inode->i_mapping,
1034 holebegin, 0, 1);
1035
1036
1037
1038
1039
1040 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) {
1041 spin_lock(&sbinfo->shrinklist_lock);
1042
1043
1044
1045
1046 if (list_empty_careful(&info->shrinklist)) {
1047 list_add_tail(&info->shrinklist,
1048 &sbinfo->shrinklist);
1049 sbinfo->shrinklist_len++;
1050 }
1051 spin_unlock(&sbinfo->shrinklist_lock);
1052 }
1053 }
1054 }
1055
1056 setattr_copy(inode, attr);
1057 if (attr->ia_valid & ATTR_MODE)
1058 error = posix_acl_chmod(inode, inode->i_mode);
1059 return error;
1060}
1061
1062static void shmem_evict_inode(struct inode *inode)
1063{
1064 struct shmem_inode_info *info = SHMEM_I(inode);
1065 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
1066
1067 if (inode->i_mapping->a_ops == &shmem_aops) {
1068 shmem_unacct_size(info->flags, inode->i_size);
1069 inode->i_size = 0;
1070 shmem_truncate_range(inode, 0, (loff_t)-1);
1071 if (!list_empty(&info->shrinklist)) {
1072 spin_lock(&sbinfo->shrinklist_lock);
1073 if (!list_empty(&info->shrinklist)) {
1074 list_del_init(&info->shrinklist);
1075 sbinfo->shrinklist_len--;
1076 }
1077 spin_unlock(&sbinfo->shrinklist_lock);
1078 }
1079 if (!list_empty(&info->swaplist)) {
1080 mutex_lock(&shmem_swaplist_mutex);
1081 list_del_init(&info->swaplist);
1082 mutex_unlock(&shmem_swaplist_mutex);
1083 }
1084 }
1085
1086 simple_xattrs_free(&info->xattrs);
1087 WARN_ON(inode->i_blocks);
1088 shmem_free_inode(inode->i_sb);
1089 clear_inode(inode);
1090}
1091
1092static unsigned long find_swap_entry(struct xarray *xa, void *item)
1093{
1094 XA_STATE(xas, xa, 0);
1095 unsigned int checked = 0;
1096 void *entry;
1097
1098 rcu_read_lock();
1099 xas_for_each(&xas, entry, ULONG_MAX) {
1100 if (xas_retry(&xas, entry))
1101 continue;
1102 if (entry == item)
1103 break;
1104 checked++;
1105 if ((checked % XA_CHECK_SCHED) != 0)
1106 continue;
1107 xas_pause(&xas);
1108 cond_resched_rcu();
1109 }
1110 rcu_read_unlock();
1111
1112 return entry ? xas.xa_index : -1;
1113}
1114
1115
1116
1117
1118static int shmem_unuse_inode(struct shmem_inode_info *info,
1119 swp_entry_t swap, struct page **pagep)
1120{
1121 struct address_space *mapping = info->vfs_inode.i_mapping;
1122 void *radswap;
1123 pgoff_t index;
1124 gfp_t gfp;
1125 int error = 0;
1126
1127 radswap = swp_to_radix_entry(swap);
1128 index = find_swap_entry(&mapping->i_pages, radswap);
1129 if (index == -1)
1130 return -EAGAIN;
1131
1132
1133
1134
1135
1136
1137
1138 if (shmem_swaplist.next != &info->swaplist)
1139 list_move_tail(&shmem_swaplist, &info->swaplist);
1140
1141 gfp = mapping_gfp_mask(mapping);
1142 if (shmem_should_replace_page(*pagep, gfp)) {
1143 mutex_unlock(&shmem_swaplist_mutex);
1144 error = shmem_replace_page(pagep, gfp, info, index);
1145 mutex_lock(&shmem_swaplist_mutex);
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164 if (!page_swapcount(*pagep))
1165 error = -ENOENT;
1166 }
1167
1168
1169
1170
1171
1172
1173 if (!error)
1174 error = shmem_add_to_page_cache(*pagep, mapping, index,
1175 radswap, gfp);
1176 if (error != -ENOMEM) {
1177
1178
1179
1180
1181 delete_from_swap_cache(*pagep);
1182 set_page_dirty(*pagep);
1183 if (!error) {
1184 spin_lock_irq(&info->lock);
1185 info->swapped--;
1186 spin_unlock_irq(&info->lock);
1187 swap_free(swap);
1188 }
1189 }
1190 return error;
1191}
1192
1193
1194
1195
1196int shmem_unuse(swp_entry_t swap, struct page *page)
1197{
1198 struct list_head *this, *next;
1199 struct shmem_inode_info *info;
1200 struct mem_cgroup *memcg;
1201 int error = 0;
1202
1203
1204
1205
1206
1207 if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val))
1208 goto out;
1209
1210
1211
1212
1213
1214
1215 error = mem_cgroup_try_charge_delay(page, current->mm, GFP_KERNEL,
1216 &memcg, false);
1217 if (error)
1218 goto out;
1219
1220 error = -EAGAIN;
1221
1222 mutex_lock(&shmem_swaplist_mutex);
1223 list_for_each_safe(this, next, &shmem_swaplist) {
1224 info = list_entry(this, struct shmem_inode_info, swaplist);
1225 if (info->swapped)
1226 error = shmem_unuse_inode(info, swap, &page);
1227 else
1228 list_del_init(&info->swaplist);
1229 cond_resched();
1230 if (error != -EAGAIN)
1231 break;
1232
1233 }
1234 mutex_unlock(&shmem_swaplist_mutex);
1235
1236 if (error) {
1237 if (error != -ENOMEM)
1238 error = 0;
1239 mem_cgroup_cancel_charge(page, memcg, false);
1240 } else
1241 mem_cgroup_commit_charge(page, memcg, true, false);
1242out:
1243 unlock_page(page);
1244 put_page(page);
1245 return error;
1246}
1247
1248
1249
1250
1251static int shmem_writepage(struct page *page, struct writeback_control *wbc)
1252{
1253 struct shmem_inode_info *info;
1254 struct address_space *mapping;
1255 struct inode *inode;
1256 swp_entry_t swap;
1257 pgoff_t index;
1258
1259 VM_BUG_ON_PAGE(PageCompound(page), page);
1260 BUG_ON(!PageLocked(page));
1261 mapping = page->mapping;
1262 index = page->index;
1263 inode = mapping->host;
1264 info = SHMEM_I(inode);
1265 if (info->flags & VM_LOCKED)
1266 goto redirty;
1267 if (!total_swap_pages)
1268 goto redirty;
1269
1270
1271
1272
1273
1274
1275
1276
1277 if (!wbc->for_reclaim) {
1278 WARN_ON_ONCE(1);
1279 goto redirty;
1280 }
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293 if (!PageUptodate(page)) {
1294 if (inode->i_private) {
1295 struct shmem_falloc *shmem_falloc;
1296 spin_lock(&inode->i_lock);
1297 shmem_falloc = inode->i_private;
1298 if (shmem_falloc &&
1299 !shmem_falloc->waitq &&
1300 index >= shmem_falloc->start &&
1301 index < shmem_falloc->next)
1302 shmem_falloc->nr_unswapped++;
1303 else
1304 shmem_falloc = NULL;
1305 spin_unlock(&inode->i_lock);
1306 if (shmem_falloc)
1307 goto redirty;
1308 }
1309 clear_highpage(page);
1310 flush_dcache_page(page);
1311 SetPageUptodate(page);
1312 }
1313
1314 swap = get_swap_page(page);
1315 if (!swap.val)
1316 goto redirty;
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326 mutex_lock(&shmem_swaplist_mutex);
1327 if (list_empty(&info->swaplist))
1328 list_add_tail(&info->swaplist, &shmem_swaplist);
1329
1330 if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
1331 spin_lock_irq(&info->lock);
1332 shmem_recalc_inode(inode);
1333 info->swapped++;
1334 spin_unlock_irq(&info->lock);
1335
1336 swap_shmem_alloc(swap);
1337 shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
1338
1339 mutex_unlock(&shmem_swaplist_mutex);
1340 BUG_ON(page_mapped(page));
1341 swap_writepage(page, wbc);
1342 return 0;
1343 }
1344
1345 mutex_unlock(&shmem_swaplist_mutex);
1346 put_swap_page(page, swap);
1347redirty:
1348 set_page_dirty(page);
1349 if (wbc->for_reclaim)
1350 return AOP_WRITEPAGE_ACTIVATE;
1351 unlock_page(page);
1352 return 0;
1353}
1354
1355#if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
1356static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
1357{
1358 char buffer[64];
1359
1360 if (!mpol || mpol->mode == MPOL_DEFAULT)
1361 return;
1362
1363 mpol_to_str(buffer, sizeof(buffer), mpol);
1364
1365 seq_printf(seq, ",mpol=%s", buffer);
1366}
1367
1368static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1369{
1370 struct mempolicy *mpol = NULL;
1371 if (sbinfo->mpol) {
1372 spin_lock(&sbinfo->stat_lock);
1373 mpol = sbinfo->mpol;
1374 mpol_get(mpol);
1375 spin_unlock(&sbinfo->stat_lock);
1376 }
1377 return mpol;
1378}
1379#else
1380static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
1381{
1382}
1383static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1384{
1385 return NULL;
1386}
1387#endif
1388#ifndef CONFIG_NUMA
1389#define vm_policy vm_private_data
1390#endif
1391
1392static void shmem_pseudo_vma_init(struct vm_area_struct *vma,
1393 struct shmem_inode_info *info, pgoff_t index)
1394{
1395
1396 vma_init(vma, NULL);
1397
1398 vma->vm_pgoff = index + info->vfs_inode.i_ino;
1399 vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index);
1400}
1401
1402static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma)
1403{
1404
1405 mpol_cond_put(vma->vm_policy);
1406}
1407
1408static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
1409 struct shmem_inode_info *info, pgoff_t index)
1410{
1411 struct vm_area_struct pvma;
1412 struct page *page;
1413 struct vm_fault vmf;
1414
1415 shmem_pseudo_vma_init(&pvma, info, index);
1416 vmf.vma = &pvma;
1417 vmf.address = 0;
1418 page = swap_cluster_readahead(swap, gfp, &vmf);
1419 shmem_pseudo_vma_destroy(&pvma);
1420
1421 return page;
1422}
1423
1424static struct page *shmem_alloc_hugepage(gfp_t gfp,
1425 struct shmem_inode_info *info, pgoff_t index)
1426{
1427 struct vm_area_struct pvma;
1428 struct address_space *mapping = info->vfs_inode.i_mapping;
1429 pgoff_t hindex;
1430 struct page *page;
1431
1432 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
1433 return NULL;
1434
1435 hindex = round_down(index, HPAGE_PMD_NR);
1436 if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1,
1437 XA_PRESENT))
1438 return NULL;
1439
1440 shmem_pseudo_vma_init(&pvma, info, hindex);
1441 page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN,
1442 HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true);
1443 shmem_pseudo_vma_destroy(&pvma);
1444 if (page)
1445 prep_transhuge_page(page);
1446 return page;
1447}
1448
1449static struct page *shmem_alloc_page(gfp_t gfp,
1450 struct shmem_inode_info *info, pgoff_t index)
1451{
1452 struct vm_area_struct pvma;
1453 struct page *page;
1454
1455 shmem_pseudo_vma_init(&pvma, info, index);
1456 page = alloc_page_vma(gfp, &pvma, 0);
1457 shmem_pseudo_vma_destroy(&pvma);
1458
1459 return page;
1460}
1461
1462static struct page *shmem_alloc_and_acct_page(gfp_t gfp,
1463 struct inode *inode,
1464 pgoff_t index, bool huge)
1465{
1466 struct shmem_inode_info *info = SHMEM_I(inode);
1467 struct page *page;
1468 int nr;
1469 int err = -ENOSPC;
1470
1471 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
1472 huge = false;
1473 nr = huge ? HPAGE_PMD_NR : 1;
1474
1475 if (!shmem_inode_acct_block(inode, nr))
1476 goto failed;
1477
1478 if (huge)
1479 page = shmem_alloc_hugepage(gfp, info, index);
1480 else
1481 page = shmem_alloc_page(gfp, info, index);
1482 if (page) {
1483 __SetPageLocked(page);
1484 __SetPageSwapBacked(page);
1485 return page;
1486 }
1487
1488 err = -ENOMEM;
1489 shmem_inode_unacct_blocks(inode, nr);
1490failed:
1491 return ERR_PTR(err);
1492}
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506static bool shmem_should_replace_page(struct page *page, gfp_t gfp)
1507{
1508 return page_zonenum(page) > gfp_zone(gfp);
1509}
1510
1511static int shmem_replace_page(struct page **pagep, gfp_t gfp,
1512 struct shmem_inode_info *info, pgoff_t index)
1513{
1514 struct page *oldpage, *newpage;
1515 struct address_space *swap_mapping;
1516 swp_entry_t entry;
1517 pgoff_t swap_index;
1518 int error;
1519
1520 oldpage = *pagep;
1521 entry.val = page_private(oldpage);
1522 swap_index = swp_offset(entry);
1523 swap_mapping = page_mapping(oldpage);
1524
1525
1526
1527
1528
1529 gfp &= ~GFP_CONSTRAINT_MASK;
1530 newpage = shmem_alloc_page(gfp, info, index);
1531 if (!newpage)
1532 return -ENOMEM;
1533
1534 get_page(newpage);
1535 copy_highpage(newpage, oldpage);
1536 flush_dcache_page(newpage);
1537
1538 __SetPageLocked(newpage);
1539 __SetPageSwapBacked(newpage);
1540 SetPageUptodate(newpage);
1541 set_page_private(newpage, entry.val);
1542 SetPageSwapCache(newpage);
1543
1544
1545
1546
1547
1548 xa_lock_irq(&swap_mapping->i_pages);
1549 error = shmem_replace_entry(swap_mapping, swap_index, oldpage, newpage);
1550 if (!error) {
1551 __inc_node_page_state(newpage, NR_FILE_PAGES);
1552 __dec_node_page_state(oldpage, NR_FILE_PAGES);
1553 }
1554 xa_unlock_irq(&swap_mapping->i_pages);
1555
1556 if (unlikely(error)) {
1557
1558
1559
1560
1561
1562 oldpage = newpage;
1563 } else {
1564 mem_cgroup_migrate(oldpage, newpage);
1565 lru_cache_add_anon(newpage);
1566 *pagep = newpage;
1567 }
1568
1569 ClearPageSwapCache(oldpage);
1570 set_page_private(oldpage, 0);
1571
1572 unlock_page(oldpage);
1573 put_page(oldpage);
1574 put_page(oldpage);
1575 return error;
1576}
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
1589 struct page **pagep, enum sgp_type sgp, gfp_t gfp,
1590 struct vm_area_struct *vma, struct vm_fault *vmf,
1591 vm_fault_t *fault_type)
1592{
1593 struct address_space *mapping = inode->i_mapping;
1594 struct shmem_inode_info *info = SHMEM_I(inode);
1595 struct shmem_sb_info *sbinfo;
1596 struct mm_struct *charge_mm;
1597 struct mem_cgroup *memcg;
1598 struct page *page;
1599 swp_entry_t swap;
1600 enum sgp_type sgp_huge = sgp;
1601 pgoff_t hindex = index;
1602 int error;
1603 int once = 0;
1604 int alloced = 0;
1605
1606 if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
1607 return -EFBIG;
1608 if (sgp == SGP_NOHUGE || sgp == SGP_HUGE)
1609 sgp = SGP_CACHE;
1610repeat:
1611 swap.val = 0;
1612 page = find_lock_entry(mapping, index);
1613 if (xa_is_value(page)) {
1614 swap = radix_to_swp_entry(page);
1615 page = NULL;
1616 }
1617
1618 if (sgp <= SGP_CACHE &&
1619 ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
1620 error = -EINVAL;
1621 goto unlock;
1622 }
1623
1624 if (page && sgp == SGP_WRITE)
1625 mark_page_accessed(page);
1626
1627
1628 if (page && !PageUptodate(page)) {
1629 if (sgp != SGP_READ)
1630 goto clear;
1631 unlock_page(page);
1632 put_page(page);
1633 page = NULL;
1634 }
1635 if (page || (sgp == SGP_READ && !swap.val)) {
1636 *pagep = page;
1637 return 0;
1638 }
1639
1640
1641
1642
1643
1644 sbinfo = SHMEM_SB(inode->i_sb);
1645 charge_mm = vma ? vma->vm_mm : current->mm;
1646
1647 if (swap.val) {
1648
1649 page = lookup_swap_cache(swap, NULL, 0);
1650 if (!page) {
1651
1652 if (fault_type) {
1653 *fault_type |= VM_FAULT_MAJOR;
1654 count_vm_event(PGMAJFAULT);
1655 count_memcg_event_mm(charge_mm, PGMAJFAULT);
1656 }
1657
1658 page = shmem_swapin(swap, gfp, info, index);
1659 if (!page) {
1660 error = -ENOMEM;
1661 goto failed;
1662 }
1663 }
1664
1665
1666 lock_page(page);
1667 if (!PageSwapCache(page) || page_private(page) != swap.val ||
1668 !shmem_confirm_swap(mapping, index, swap)) {
1669 error = -EEXIST;
1670 goto unlock;
1671 }
1672 if (!PageUptodate(page)) {
1673 error = -EIO;
1674 goto failed;
1675 }
1676 wait_on_page_writeback(page);
1677
1678 if (shmem_should_replace_page(page, gfp)) {
1679 error = shmem_replace_page(&page, gfp, info, index);
1680 if (error)
1681 goto failed;
1682 }
1683
1684 error = mem_cgroup_try_charge_delay(page, charge_mm, gfp, &memcg,
1685 false);
1686 if (!error) {
1687 error = shmem_add_to_page_cache(page, mapping, index,
1688 swp_to_radix_entry(swap), gfp);
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701 if (error) {
1702 mem_cgroup_cancel_charge(page, memcg, false);
1703 delete_from_swap_cache(page);
1704 }
1705 }
1706 if (error)
1707 goto failed;
1708
1709 mem_cgroup_commit_charge(page, memcg, true, false);
1710
1711 spin_lock_irq(&info->lock);
1712 info->swapped--;
1713 shmem_recalc_inode(inode);
1714 spin_unlock_irq(&info->lock);
1715
1716 if (sgp == SGP_WRITE)
1717 mark_page_accessed(page);
1718
1719 delete_from_swap_cache(page);
1720 set_page_dirty(page);
1721 swap_free(swap);
1722
1723 } else {
1724 if (vma && userfaultfd_missing(vma)) {
1725 *fault_type = handle_userfault(vmf, VM_UFFD_MISSING);
1726 return 0;
1727 }
1728
1729
1730 if (mapping->a_ops != &shmem_aops)
1731 goto alloc_nohuge;
1732 if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE)
1733 goto alloc_nohuge;
1734 if (shmem_huge == SHMEM_HUGE_FORCE)
1735 goto alloc_huge;
1736 switch (sbinfo->huge) {
1737 loff_t i_size;
1738 pgoff_t off;
1739 case SHMEM_HUGE_NEVER:
1740 goto alloc_nohuge;
1741 case SHMEM_HUGE_WITHIN_SIZE:
1742 off = round_up(index, HPAGE_PMD_NR);
1743 i_size = round_up(i_size_read(inode), PAGE_SIZE);
1744 if (i_size >= HPAGE_PMD_SIZE &&
1745 i_size >> PAGE_SHIFT >= off)
1746 goto alloc_huge;
1747
1748 case SHMEM_HUGE_ADVISE:
1749 if (sgp_huge == SGP_HUGE)
1750 goto alloc_huge;
1751
1752 goto alloc_nohuge;
1753 }
1754
1755alloc_huge:
1756 page = shmem_alloc_and_acct_page(gfp, inode, index, true);
1757 if (IS_ERR(page)) {
1758alloc_nohuge: page = shmem_alloc_and_acct_page(gfp, inode,
1759 index, false);
1760 }
1761 if (IS_ERR(page)) {
1762 int retry = 5;
1763 error = PTR_ERR(page);
1764 page = NULL;
1765 if (error != -ENOSPC)
1766 goto failed;
1767
1768
1769
1770
1771 while (retry--) {
1772 int ret;
1773 ret = shmem_unused_huge_shrink(sbinfo, NULL, 1);
1774 if (ret == SHRINK_STOP)
1775 break;
1776 if (ret)
1777 goto alloc_nohuge;
1778 }
1779 goto failed;
1780 }
1781
1782 if (PageTransHuge(page))
1783 hindex = round_down(index, HPAGE_PMD_NR);
1784 else
1785 hindex = index;
1786
1787 if (sgp == SGP_WRITE)
1788 __SetPageReferenced(page);
1789
1790 error = mem_cgroup_try_charge_delay(page, charge_mm, gfp, &memcg,
1791 PageTransHuge(page));
1792 if (error)
1793 goto unacct;
1794 error = shmem_add_to_page_cache(page, mapping, hindex,
1795 NULL, gfp & GFP_RECLAIM_MASK);
1796 if (error) {
1797 mem_cgroup_cancel_charge(page, memcg,
1798 PageTransHuge(page));
1799 goto unacct;
1800 }
1801 mem_cgroup_commit_charge(page, memcg, false,
1802 PageTransHuge(page));
1803 lru_cache_add_anon(page);
1804
1805 spin_lock_irq(&info->lock);
1806 info->alloced += 1 << compound_order(page);
1807 inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page);
1808 shmem_recalc_inode(inode);
1809 spin_unlock_irq(&info->lock);
1810 alloced = true;
1811
1812 if (PageTransHuge(page) &&
1813 DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) <
1814 hindex + HPAGE_PMD_NR - 1) {
1815
1816
1817
1818
1819 spin_lock(&sbinfo->shrinklist_lock);
1820
1821
1822
1823
1824 if (list_empty_careful(&info->shrinklist)) {
1825 list_add_tail(&info->shrinklist,
1826 &sbinfo->shrinklist);
1827 sbinfo->shrinklist_len++;
1828 }
1829 spin_unlock(&sbinfo->shrinklist_lock);
1830 }
1831
1832
1833
1834
1835 if (sgp == SGP_FALLOC)
1836 sgp = SGP_WRITE;
1837clear:
1838
1839
1840
1841
1842
1843 if (sgp != SGP_WRITE && !PageUptodate(page)) {
1844 struct page *head = compound_head(page);
1845 int i;
1846
1847 for (i = 0; i < (1 << compound_order(head)); i++) {
1848 clear_highpage(head + i);
1849 flush_dcache_page(head + i);
1850 }
1851 SetPageUptodate(head);
1852 }
1853 }
1854
1855
1856 if (sgp <= SGP_CACHE &&
1857 ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
1858 if (alloced) {
1859 ClearPageDirty(page);
1860 delete_from_page_cache(page);
1861 spin_lock_irq(&info->lock);
1862 shmem_recalc_inode(inode);
1863 spin_unlock_irq(&info->lock);
1864 }
1865 error = -EINVAL;
1866 goto unlock;
1867 }
1868 *pagep = page + index - hindex;
1869 return 0;
1870
1871
1872
1873
1874unacct:
1875 shmem_inode_unacct_blocks(inode, 1 << compound_order(page));
1876
1877 if (PageTransHuge(page)) {
1878 unlock_page(page);
1879 put_page(page);
1880 goto alloc_nohuge;
1881 }
1882failed:
1883 if (swap.val && !shmem_confirm_swap(mapping, index, swap))
1884 error = -EEXIST;
1885unlock:
1886 if (page) {
1887 unlock_page(page);
1888 put_page(page);
1889 }
1890 if (error == -ENOSPC && !once++) {
1891 spin_lock_irq(&info->lock);
1892 shmem_recalc_inode(inode);
1893 spin_unlock_irq(&info->lock);
1894 goto repeat;
1895 }
1896 if (error == -EEXIST)
1897 goto repeat;
1898 return error;
1899}
1900
1901
1902
1903
1904
1905
1906static int synchronous_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
1907{
1908 int ret = default_wake_function(wait, mode, sync, key);
1909 list_del_init(&wait->entry);
1910 return ret;
1911}
1912
1913static vm_fault_t shmem_fault(struct vm_fault *vmf)
1914{
1915 struct vm_area_struct *vma = vmf->vma;
1916 struct inode *inode = file_inode(vma->vm_file);
1917 gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
1918 enum sgp_type sgp;
1919 int err;
1920 vm_fault_t ret = VM_FAULT_LOCKED;
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939 if (unlikely(inode->i_private)) {
1940 struct shmem_falloc *shmem_falloc;
1941
1942 spin_lock(&inode->i_lock);
1943 shmem_falloc = inode->i_private;
1944 if (shmem_falloc &&
1945 shmem_falloc->waitq &&
1946 vmf->pgoff >= shmem_falloc->start &&
1947 vmf->pgoff < shmem_falloc->next) {
1948 wait_queue_head_t *shmem_falloc_waitq;
1949 DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function);
1950
1951 ret = VM_FAULT_NOPAGE;
1952 if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) &&
1953 !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
1954
1955 up_read(&vma->vm_mm->mmap_sem);
1956 ret = VM_FAULT_RETRY;
1957 }
1958
1959 shmem_falloc_waitq = shmem_falloc->waitq;
1960 prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait,
1961 TASK_UNINTERRUPTIBLE);
1962 spin_unlock(&inode->i_lock);
1963 schedule();
1964
1965
1966
1967
1968
1969
1970
1971
1972 spin_lock(&inode->i_lock);
1973 finish_wait(shmem_falloc_waitq, &shmem_fault_wait);
1974 spin_unlock(&inode->i_lock);
1975 return ret;
1976 }
1977 spin_unlock(&inode->i_lock);
1978 }
1979
1980 sgp = SGP_CACHE;
1981
1982 if ((vma->vm_flags & VM_NOHUGEPAGE) ||
1983 test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
1984 sgp = SGP_NOHUGE;
1985 else if (vma->vm_flags & VM_HUGEPAGE)
1986 sgp = SGP_HUGE;
1987
1988 err = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp,
1989 gfp, vma, vmf, &ret);
1990 if (err)
1991 return vmf_error(err);
1992 return ret;
1993}
1994
1995unsigned long shmem_get_unmapped_area(struct file *file,
1996 unsigned long uaddr, unsigned long len,
1997 unsigned long pgoff, unsigned long flags)
1998{
1999 unsigned long (*get_area)(struct file *,
2000 unsigned long, unsigned long, unsigned long, unsigned long);
2001 unsigned long addr;
2002 unsigned long offset;
2003 unsigned long inflated_len;
2004 unsigned long inflated_addr;
2005 unsigned long inflated_offset;
2006
2007 if (len > TASK_SIZE)
2008 return -ENOMEM;
2009
2010 get_area = current->mm->get_unmapped_area;
2011 addr = get_area(file, uaddr, len, pgoff, flags);
2012
2013 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
2014 return addr;
2015 if (IS_ERR_VALUE(addr))
2016 return addr;
2017 if (addr & ~PAGE_MASK)
2018 return addr;
2019 if (addr > TASK_SIZE - len)
2020 return addr;
2021
2022 if (shmem_huge == SHMEM_HUGE_DENY)
2023 return addr;
2024 if (len < HPAGE_PMD_SIZE)
2025 return addr;
2026 if (flags & MAP_FIXED)
2027 return addr;
2028
2029
2030
2031
2032
2033 if (uaddr)
2034 return addr;
2035
2036 if (shmem_huge != SHMEM_HUGE_FORCE) {
2037 struct super_block *sb;
2038
2039 if (file) {
2040 VM_BUG_ON(file->f_op != &shmem_file_operations);
2041 sb = file_inode(file)->i_sb;
2042 } else {
2043
2044
2045
2046
2047 if (IS_ERR(shm_mnt))
2048 return addr;
2049 sb = shm_mnt->mnt_sb;
2050 }
2051 if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER)
2052 return addr;
2053 }
2054
2055 offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1);
2056 if (offset && offset + len < 2 * HPAGE_PMD_SIZE)
2057 return addr;
2058 if ((addr & (HPAGE_PMD_SIZE-1)) == offset)
2059 return addr;
2060
2061 inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;
2062 if (inflated_len > TASK_SIZE)
2063 return addr;
2064 if (inflated_len < len)
2065 return addr;
2066
2067 inflated_addr = get_area(NULL, 0, inflated_len, 0, flags);
2068 if (IS_ERR_VALUE(inflated_addr))
2069 return addr;
2070 if (inflated_addr & ~PAGE_MASK)
2071 return addr;
2072
2073 inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
2074 inflated_addr += offset - inflated_offset;
2075 if (inflated_offset > offset)
2076 inflated_addr += HPAGE_PMD_SIZE;
2077
2078 if (inflated_addr > TASK_SIZE - len)
2079 return addr;
2080 return inflated_addr;
2081}
2082
2083#ifdef CONFIG_NUMA
2084static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
2085{
2086 struct inode *inode = file_inode(vma->vm_file);
2087 return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol);
2088}
2089
2090static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
2091 unsigned long addr)
2092{
2093 struct inode *inode = file_inode(vma->vm_file);
2094 pgoff_t index;
2095
2096 index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
2097 return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index);
2098}
2099#endif
2100
2101int shmem_lock(struct file *file, int lock, struct user_struct *user)
2102{
2103 struct inode *inode = file_inode(file);
2104 struct shmem_inode_info *info = SHMEM_I(inode);
2105 int retval = -ENOMEM;
2106
2107 spin_lock_irq(&info->lock);
2108 if (lock && !(info->flags & VM_LOCKED)) {
2109 if (!user_shm_lock(inode->i_size, user))
2110 goto out_nomem;
2111 info->flags |= VM_LOCKED;
2112 mapping_set_unevictable(file->f_mapping);
2113 }
2114 if (!lock && (info->flags & VM_LOCKED) && user) {
2115 user_shm_unlock(inode->i_size, user);
2116 info->flags &= ~VM_LOCKED;
2117 mapping_clear_unevictable(file->f_mapping);
2118 }
2119 retval = 0;
2120
2121out_nomem:
2122 spin_unlock_irq(&info->lock);
2123 return retval;
2124}
2125
2126static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
2127{
2128 file_accessed(file);
2129 vma->vm_ops = &shmem_vm_ops;
2130 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
2131 ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
2132 (vma->vm_end & HPAGE_PMD_MASK)) {
2133 khugepaged_enter(vma, vma->vm_flags);
2134 }
2135 return 0;
2136}
2137
2138static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir,
2139 umode_t mode, dev_t dev, unsigned long flags)
2140{
2141 struct inode *inode;
2142 struct shmem_inode_info *info;
2143 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
2144
2145 if (shmem_reserve_inode(sb))
2146 return NULL;
2147
2148 inode = new_inode(sb);
2149 if (inode) {
2150 inode->i_ino = get_next_ino();
2151 inode_init_owner(inode, dir, mode);
2152 inode->i_blocks = 0;
2153 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
2154 inode->i_generation = prandom_u32();
2155 info = SHMEM_I(inode);
2156 memset(info, 0, (char *)inode - (char *)info);
2157 spin_lock_init(&info->lock);
2158 info->seals = F_SEAL_SEAL;
2159 info->flags = flags & VM_NORESERVE;
2160 INIT_LIST_HEAD(&info->shrinklist);
2161 INIT_LIST_HEAD(&info->swaplist);
2162 simple_xattrs_init(&info->xattrs);
2163 cache_no_acl(inode);
2164
2165 switch (mode & S_IFMT) {
2166 default:
2167 inode->i_op = &shmem_special_inode_operations;
2168 init_special_inode(inode, mode, dev);
2169 break;
2170 case S_IFREG:
2171 inode->i_mapping->a_ops = &shmem_aops;
2172 inode->i_op = &shmem_inode_operations;
2173 inode->i_fop = &shmem_file_operations;
2174 mpol_shared_policy_init(&info->policy,
2175 shmem_get_sbmpol(sbinfo));
2176 break;
2177 case S_IFDIR:
2178 inc_nlink(inode);
2179
2180 inode->i_size = 2 * BOGO_DIRENT_SIZE;
2181 inode->i_op = &shmem_dir_inode_operations;
2182 inode->i_fop = &simple_dir_operations;
2183 break;
2184 case S_IFLNK:
2185
2186
2187
2188
2189 mpol_shared_policy_init(&info->policy, NULL);
2190 break;
2191 }
2192
2193 lockdep_annotate_inode_mutex_key(inode);
2194 } else
2195 shmem_free_inode(sb);
2196 return inode;
2197}
2198
2199bool shmem_mapping(struct address_space *mapping)
2200{
2201 return mapping->a_ops == &shmem_aops;
2202}
2203
2204static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
2205 pmd_t *dst_pmd,
2206 struct vm_area_struct *dst_vma,
2207 unsigned long dst_addr,
2208 unsigned long src_addr,
2209 bool zeropage,
2210 struct page **pagep)
2211{
2212 struct inode *inode = file_inode(dst_vma->vm_file);
2213 struct shmem_inode_info *info = SHMEM_I(inode);
2214 struct address_space *mapping = inode->i_mapping;
2215 gfp_t gfp = mapping_gfp_mask(mapping);
2216 pgoff_t pgoff = linear_page_index(dst_vma, dst_addr);
2217 struct mem_cgroup *memcg;
2218 spinlock_t *ptl;
2219 void *page_kaddr;
2220 struct page *page;
2221 pte_t _dst_pte, *dst_pte;
2222 int ret;
2223 pgoff_t offset, max_off;
2224
2225 ret = -ENOMEM;
2226 if (!shmem_inode_acct_block(inode, 1))
2227 goto out;
2228
2229 if (!*pagep) {
2230 page = shmem_alloc_page(gfp, info, pgoff);
2231 if (!page)
2232 goto out_unacct_blocks;
2233
2234 if (!zeropage) {
2235 page_kaddr = kmap_atomic(page);
2236 ret = copy_from_user(page_kaddr,
2237 (const void __user *)src_addr,
2238 PAGE_SIZE);
2239 kunmap_atomic(page_kaddr);
2240
2241
2242 if (unlikely(ret)) {
2243 *pagep = page;
2244 shmem_inode_unacct_blocks(inode, 1);
2245
2246 return -ENOENT;
2247 }
2248 } else {
2249 clear_highpage(page);
2250 }
2251 } else {
2252 page = *pagep;
2253 *pagep = NULL;
2254 }
2255
2256 VM_BUG_ON(PageLocked(page) || PageSwapBacked(page));
2257 __SetPageLocked(page);
2258 __SetPageSwapBacked(page);
2259 __SetPageUptodate(page);
2260
2261 ret = -EFAULT;
2262 offset = linear_page_index(dst_vma, dst_addr);
2263 max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
2264 if (unlikely(offset >= max_off))
2265 goto out_release;
2266
2267 ret = mem_cgroup_try_charge_delay(page, dst_mm, gfp, &memcg, false);
2268 if (ret)
2269 goto out_release;
2270
2271 ret = shmem_add_to_page_cache(page, mapping, pgoff, NULL,
2272 gfp & GFP_RECLAIM_MASK);
2273 if (ret)
2274 goto out_release_uncharge;
2275
2276 mem_cgroup_commit_charge(page, memcg, false, false);
2277
2278 _dst_pte = mk_pte(page, dst_vma->vm_page_prot);
2279 if (dst_vma->vm_flags & VM_WRITE)
2280 _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
2281 else {
2282
2283
2284
2285
2286
2287
2288
2289 set_page_dirty(page);
2290 }
2291
2292 dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
2293
2294 ret = -EFAULT;
2295 max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
2296 if (unlikely(offset >= max_off))
2297 goto out_release_uncharge_unlock;
2298
2299 ret = -EEXIST;
2300 if (!pte_none(*dst_pte))
2301 goto out_release_uncharge_unlock;
2302
2303 lru_cache_add_anon(page);
2304
2305 spin_lock(&info->lock);
2306 info->alloced++;
2307 inode->i_blocks += BLOCKS_PER_PAGE;
2308 shmem_recalc_inode(inode);
2309 spin_unlock(&info->lock);
2310
2311 inc_mm_counter(dst_mm, mm_counter_file(page));
2312 page_add_file_rmap(page, false);
2313 set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
2314
2315
2316 update_mmu_cache(dst_vma, dst_addr, dst_pte);
2317 pte_unmap_unlock(dst_pte, ptl);
2318 unlock_page(page);
2319 ret = 0;
2320out:
2321 return ret;
2322out_release_uncharge_unlock:
2323 pte_unmap_unlock(dst_pte, ptl);
2324 ClearPageDirty(page);
2325 delete_from_page_cache(page);
2326out_release_uncharge:
2327 mem_cgroup_cancel_charge(page, memcg, false);
2328out_release:
2329 unlock_page(page);
2330 put_page(page);
2331out_unacct_blocks:
2332 shmem_inode_unacct_blocks(inode, 1);
2333 goto out;
2334}
2335
2336int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm,
2337 pmd_t *dst_pmd,
2338 struct vm_area_struct *dst_vma,
2339 unsigned long dst_addr,
2340 unsigned long src_addr,
2341 struct page **pagep)
2342{
2343 return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
2344 dst_addr, src_addr, false, pagep);
2345}
2346
2347int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
2348 pmd_t *dst_pmd,
2349 struct vm_area_struct *dst_vma,
2350 unsigned long dst_addr)
2351{
2352 struct page *page = NULL;
2353
2354 return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
2355 dst_addr, 0, true, &page);
2356}
2357
2358#ifdef CONFIG_TMPFS
2359static const struct inode_operations shmem_symlink_inode_operations;
2360static const struct inode_operations shmem_short_symlink_operations;
2361
2362#ifdef CONFIG_TMPFS_XATTR
2363static int shmem_initxattrs(struct inode *, const struct xattr *, void *);
2364#else
2365#define shmem_initxattrs NULL
2366#endif
2367
2368static int
2369shmem_write_begin(struct file *file, struct address_space *mapping,
2370 loff_t pos, unsigned len, unsigned flags,
2371 struct page **pagep, void **fsdata)
2372{
2373 struct inode *inode = mapping->host;
2374 struct shmem_inode_info *info = SHMEM_I(inode);
2375 pgoff_t index = pos >> PAGE_SHIFT;
2376
2377
2378 if (unlikely(info->seals & (F_SEAL_WRITE | F_SEAL_GROW))) {
2379 if (info->seals & F_SEAL_WRITE)
2380 return -EPERM;
2381 if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size)
2382 return -EPERM;
2383 }
2384
2385 return shmem_getpage(inode, index, pagep, SGP_WRITE);
2386}
2387
2388static int
2389shmem_write_end(struct file *file, struct address_space *mapping,
2390 loff_t pos, unsigned len, unsigned copied,
2391 struct page *page, void *fsdata)
2392{
2393 struct inode *inode = mapping->host;
2394
2395 if (pos + copied > inode->i_size)
2396 i_size_write(inode, pos + copied);
2397
2398 if (!PageUptodate(page)) {
2399 struct page *head = compound_head(page);
2400 if (PageTransCompound(page)) {
2401 int i;
2402
2403 for (i = 0; i < HPAGE_PMD_NR; i++) {
2404 if (head + i == page)
2405 continue;
2406 clear_highpage(head + i);
2407 flush_dcache_page(head + i);
2408 }
2409 }
2410 if (copied < PAGE_SIZE) {
2411 unsigned from = pos & (PAGE_SIZE - 1);
2412 zero_user_segments(page, 0, from,
2413 from + copied, PAGE_SIZE);
2414 }
2415 SetPageUptodate(head);
2416 }
2417 set_page_dirty(page);
2418 unlock_page(page);
2419 put_page(page);
2420
2421 return copied;
2422}
2423
2424static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
2425{
2426 struct file *file = iocb->ki_filp;
2427 struct inode *inode = file_inode(file);
2428 struct address_space *mapping = inode->i_mapping;
2429 pgoff_t index;
2430 unsigned long offset;
2431 enum sgp_type sgp = SGP_READ;
2432 int error = 0;
2433 ssize_t retval = 0;
2434 loff_t *ppos = &iocb->ki_pos;
2435
2436
2437
2438
2439
2440
2441 if (!iter_is_iovec(to))
2442 sgp = SGP_CACHE;
2443
2444 index = *ppos >> PAGE_SHIFT;
2445 offset = *ppos & ~PAGE_MASK;
2446
2447 for (;;) {
2448 struct page *page = NULL;
2449 pgoff_t end_index;
2450 unsigned long nr, ret;
2451 loff_t i_size = i_size_read(inode);
2452
2453 end_index = i_size >> PAGE_SHIFT;
2454 if (index > end_index)
2455 break;
2456 if (index == end_index) {
2457 nr = i_size & ~PAGE_MASK;
2458 if (nr <= offset)
2459 break;
2460 }
2461
2462 error = shmem_getpage(inode, index, &page, sgp);
2463 if (error) {
2464 if (error == -EINVAL)
2465 error = 0;
2466 break;
2467 }
2468 if (page) {
2469 if (sgp == SGP_CACHE)
2470 set_page_dirty(page);
2471 unlock_page(page);
2472 }
2473
2474
2475
2476
2477
2478 nr = PAGE_SIZE;
2479 i_size = i_size_read(inode);
2480 end_index = i_size >> PAGE_SHIFT;
2481 if (index == end_index) {
2482 nr = i_size & ~PAGE_MASK;
2483 if (nr <= offset) {
2484 if (page)
2485 put_page(page);
2486 break;
2487 }
2488 }
2489 nr -= offset;
2490
2491 if (page) {
2492
2493
2494
2495
2496
2497 if (mapping_writably_mapped(mapping))
2498 flush_dcache_page(page);
2499
2500
2501
2502 if (!offset)
2503 mark_page_accessed(page);
2504 } else {
2505 page = ZERO_PAGE(0);
2506 get_page(page);
2507 }
2508
2509
2510
2511
2512
2513 ret = copy_page_to_iter(page, offset, nr, to);
2514 retval += ret;
2515 offset += ret;
2516 index += offset >> PAGE_SHIFT;
2517 offset &= ~PAGE_MASK;
2518
2519 put_page(page);
2520 if (!iov_iter_count(to))
2521 break;
2522 if (ret < nr) {
2523 error = -EFAULT;
2524 break;
2525 }
2526 cond_resched();
2527 }
2528
2529 *ppos = ((loff_t) index << PAGE_SHIFT) + offset;
2530 file_accessed(file);
2531 return retval ? retval : error;
2532}
2533
2534
2535
2536
2537static pgoff_t shmem_seek_hole_data(struct address_space *mapping,
2538 pgoff_t index, pgoff_t end, int whence)
2539{
2540 struct page *page;
2541 struct pagevec pvec;
2542 pgoff_t indices[PAGEVEC_SIZE];
2543 bool done = false;
2544 int i;
2545
2546 pagevec_init(&pvec);
2547 pvec.nr = 1;
2548 while (!done) {
2549 pvec.nr = find_get_entries(mapping, index,
2550 pvec.nr, pvec.pages, indices);
2551 if (!pvec.nr) {
2552 if (whence == SEEK_DATA)
2553 index = end;
2554 break;
2555 }
2556 for (i = 0; i < pvec.nr; i++, index++) {
2557 if (index < indices[i]) {
2558 if (whence == SEEK_HOLE) {
2559 done = true;
2560 break;
2561 }
2562 index = indices[i];
2563 }
2564 page = pvec.pages[i];
2565 if (page && !xa_is_value(page)) {
2566 if (!PageUptodate(page))
2567 page = NULL;
2568 }
2569 if (index >= end ||
2570 (page && whence == SEEK_DATA) ||
2571 (!page && whence == SEEK_HOLE)) {
2572 done = true;
2573 break;
2574 }
2575 }
2576 pagevec_remove_exceptionals(&pvec);
2577 pagevec_release(&pvec);
2578 pvec.nr = PAGEVEC_SIZE;
2579 cond_resched();
2580 }
2581 return index;
2582}
2583
2584static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
2585{
2586 struct address_space *mapping = file->f_mapping;
2587 struct inode *inode = mapping->host;
2588 pgoff_t start, end;
2589 loff_t new_offset;
2590
2591 if (whence != SEEK_DATA && whence != SEEK_HOLE)
2592 return generic_file_llseek_size(file, offset, whence,
2593 MAX_LFS_FILESIZE, i_size_read(inode));
2594 inode_lock(inode);
2595
2596
2597 if (offset < 0 || offset >= inode->i_size)
2598 offset = -ENXIO;
2599 else {
2600 start = offset >> PAGE_SHIFT;
2601 end = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2602 new_offset = shmem_seek_hole_data(mapping, start, end, whence);
2603 new_offset <<= PAGE_SHIFT;
2604 if (new_offset > offset) {
2605 if (new_offset < inode->i_size)
2606 offset = new_offset;
2607 else if (whence == SEEK_DATA)
2608 offset = -ENXIO;
2609 else
2610 offset = inode->i_size;
2611 }
2612 }
2613
2614 if (offset >= 0)
2615 offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE);
2616 inode_unlock(inode);
2617 return offset;
2618}
2619
2620static long shmem_fallocate(struct file *file, int mode, loff_t offset,
2621 loff_t len)
2622{
2623 struct inode *inode = file_inode(file);
2624 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
2625 struct shmem_inode_info *info = SHMEM_I(inode);
2626 struct shmem_falloc shmem_falloc;
2627 pgoff_t start, index, end;
2628 int error;
2629
2630 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2631 return -EOPNOTSUPP;
2632
2633 inode_lock(inode);
2634
2635 if (mode & FALLOC_FL_PUNCH_HOLE) {
2636 struct address_space *mapping = file->f_mapping;
2637 loff_t unmap_start = round_up(offset, PAGE_SIZE);
2638 loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1;
2639 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq);
2640
2641
2642 if (info->seals & F_SEAL_WRITE) {
2643 error = -EPERM;
2644 goto out;
2645 }
2646
2647 shmem_falloc.waitq = &shmem_falloc_waitq;
2648 shmem_falloc.start = unmap_start >> PAGE_SHIFT;
2649 shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
2650 spin_lock(&inode->i_lock);
2651 inode->i_private = &shmem_falloc;
2652 spin_unlock(&inode->i_lock);
2653
2654 if ((u64)unmap_end > (u64)unmap_start)
2655 unmap_mapping_range(mapping, unmap_start,
2656 1 + unmap_end - unmap_start, 0);
2657 shmem_truncate_range(inode, offset, offset + len - 1);
2658
2659
2660 spin_lock(&inode->i_lock);
2661 inode->i_private = NULL;
2662 wake_up_all(&shmem_falloc_waitq);
2663 WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.head));
2664 spin_unlock(&inode->i_lock);
2665 error = 0;
2666 goto out;
2667 }
2668
2669
2670 error = inode_newsize_ok(inode, offset + len);
2671 if (error)
2672 goto out;
2673
2674 if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
2675 error = -EPERM;
2676 goto out;
2677 }
2678
2679 start = offset >> PAGE_SHIFT;
2680 end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
2681
2682 if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) {
2683 error = -ENOSPC;
2684 goto out;
2685 }
2686
2687 shmem_falloc.waitq = NULL;
2688 shmem_falloc.start = start;
2689 shmem_falloc.next = start;
2690 shmem_falloc.nr_falloced = 0;
2691 shmem_falloc.nr_unswapped = 0;
2692 spin_lock(&inode->i_lock);
2693 inode->i_private = &shmem_falloc;
2694 spin_unlock(&inode->i_lock);
2695
2696 for (index = start; index < end; index++) {
2697 struct page *page;
2698
2699
2700
2701
2702
2703 if (signal_pending(current))
2704 error = -EINTR;
2705 else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced)
2706 error = -ENOMEM;
2707 else
2708 error = shmem_getpage(inode, index, &page, SGP_FALLOC);
2709 if (error) {
2710
2711 if (index > start) {
2712 shmem_undo_range(inode,
2713 (loff_t)start << PAGE_SHIFT,
2714 ((loff_t)index << PAGE_SHIFT) - 1, true);
2715 }
2716 goto undone;
2717 }
2718
2719
2720
2721
2722
2723 shmem_falloc.next++;
2724 if (!PageUptodate(page))
2725 shmem_falloc.nr_falloced++;
2726
2727
2728
2729
2730
2731
2732
2733
2734 set_page_dirty(page);
2735 unlock_page(page);
2736 put_page(page);
2737 cond_resched();
2738 }
2739
2740 if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
2741 i_size_write(inode, offset + len);
2742 inode->i_ctime = current_time(inode);
2743undone:
2744 spin_lock(&inode->i_lock);
2745 inode->i_private = NULL;
2746 spin_unlock(&inode->i_lock);
2747out:
2748 inode_unlock(inode);
2749 return error;
2750}
2751
2752static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
2753{
2754 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
2755
2756 buf->f_type = TMPFS_MAGIC;
2757 buf->f_bsize = PAGE_SIZE;
2758 buf->f_namelen = NAME_MAX;
2759 if (sbinfo->max_blocks) {
2760 buf->f_blocks = sbinfo->max_blocks;
2761 buf->f_bavail =
2762 buf->f_bfree = sbinfo->max_blocks -
2763 percpu_counter_sum(&sbinfo->used_blocks);
2764 }
2765 if (sbinfo->max_inodes) {
2766 buf->f_files = sbinfo->max_inodes;
2767 buf->f_ffree = sbinfo->free_inodes;
2768 }
2769
2770 return 0;
2771}
2772
2773
2774
2775
2776static int
2777shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
2778{
2779 struct inode *inode;
2780 int error = -ENOSPC;
2781
2782 inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
2783 if (inode) {
2784 error = simple_acl_create(dir, inode);
2785 if (error)
2786 goto out_iput;
2787 error = security_inode_init_security(inode, dir,
2788 &dentry->d_name,
2789 shmem_initxattrs, NULL);
2790 if (error && error != -EOPNOTSUPP)
2791 goto out_iput;
2792
2793 error = 0;
2794 dir->i_size += BOGO_DIRENT_SIZE;
2795 dir->i_ctime = dir->i_mtime = current_time(dir);
2796 d_instantiate(dentry, inode);
2797 dget(dentry);
2798 }
2799 return error;
2800out_iput:
2801 iput(inode);
2802 return error;
2803}
2804
2805static int
2806shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
2807{
2808 struct inode *inode;
2809 int error = -ENOSPC;
2810
2811 inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE);
2812 if (inode) {
2813 error = security_inode_init_security(inode, dir,
2814 NULL,
2815 shmem_initxattrs, NULL);
2816 if (error && error != -EOPNOTSUPP)
2817 goto out_iput;
2818 error = simple_acl_create(dir, inode);
2819 if (error)
2820 goto out_iput;
2821 d_tmpfile(dentry, inode);
2822 }
2823 return error;
2824out_iput:
2825 iput(inode);
2826 return error;
2827}
2828
2829static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
2830{
2831 int error;
2832
2833 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
2834 return error;
2835 inc_nlink(dir);
2836 return 0;
2837}
2838
2839static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode,
2840 bool excl)
2841{
2842 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
2843}
2844
2845
2846
2847
2848static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
2849{
2850 struct inode *inode = d_inode(old_dentry);
2851 int ret = 0;
2852
2853
2854
2855
2856
2857
2858
2859
2860 if (inode->i_nlink) {
2861 ret = shmem_reserve_inode(inode->i_sb);
2862 if (ret)
2863 goto out;
2864 }
2865
2866 dir->i_size += BOGO_DIRENT_SIZE;
2867 inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2868 inc_nlink(inode);
2869 ihold(inode);
2870 dget(dentry);
2871 d_instantiate(dentry, inode);
2872out:
2873 return ret;
2874}
2875
2876static int shmem_unlink(struct inode *dir, struct dentry *dentry)
2877{
2878 struct inode *inode = d_inode(dentry);
2879
2880 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
2881 shmem_free_inode(inode->i_sb);
2882
2883 dir->i_size -= BOGO_DIRENT_SIZE;
2884 inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
2885 drop_nlink(inode);
2886 dput(dentry);
2887 return 0;
2888}
2889
2890static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
2891{
2892 if (!simple_empty(dentry))
2893 return -ENOTEMPTY;
2894
2895 drop_nlink(d_inode(dentry));
2896 drop_nlink(dir);
2897 return shmem_unlink(dir, dentry);
2898}
2899
2900static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
2901{
2902 bool old_is_dir = d_is_dir(old_dentry);
2903 bool new_is_dir = d_is_dir(new_dentry);
2904
2905 if (old_dir != new_dir && old_is_dir != new_is_dir) {
2906 if (old_is_dir) {
2907 drop_nlink(old_dir);
2908 inc_nlink(new_dir);
2909 } else {
2910 drop_nlink(new_dir);
2911 inc_nlink(old_dir);
2912 }
2913 }
2914 old_dir->i_ctime = old_dir->i_mtime =
2915 new_dir->i_ctime = new_dir->i_mtime =
2916 d_inode(old_dentry)->i_ctime =
2917 d_inode(new_dentry)->i_ctime = current_time(old_dir);
2918
2919 return 0;
2920}
2921
2922static int shmem_whiteout(struct inode *old_dir, struct dentry *old_dentry)
2923{
2924 struct dentry *whiteout;
2925 int error;
2926
2927 whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
2928 if (!whiteout)
2929 return -ENOMEM;
2930
2931 error = shmem_mknod(old_dir, whiteout,
2932 S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
2933 dput(whiteout);
2934 if (error)
2935 return error;
2936
2937
2938
2939
2940
2941
2942
2943
2944 d_rehash(whiteout);
2945 return 0;
2946}
2947
2948
2949
2950
2951
2952
2953
2954static int shmem_rename2(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags)
2955{
2956 struct inode *inode = d_inode(old_dentry);
2957 int they_are_dirs = S_ISDIR(inode->i_mode);
2958
2959 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
2960 return -EINVAL;
2961
2962 if (flags & RENAME_EXCHANGE)
2963 return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry);
2964
2965 if (!simple_empty(new_dentry))
2966 return -ENOTEMPTY;
2967
2968 if (flags & RENAME_WHITEOUT) {
2969 int error;
2970
2971 error = shmem_whiteout(old_dir, old_dentry);
2972 if (error)
2973 return error;
2974 }
2975
2976 if (d_really_is_positive(new_dentry)) {
2977 (void) shmem_unlink(new_dir, new_dentry);
2978 if (they_are_dirs) {
2979 drop_nlink(d_inode(new_dentry));
2980 drop_nlink(old_dir);
2981 }
2982 } else if (they_are_dirs) {
2983 drop_nlink(old_dir);
2984 inc_nlink(new_dir);
2985 }
2986
2987 old_dir->i_size -= BOGO_DIRENT_SIZE;
2988 new_dir->i_size += BOGO_DIRENT_SIZE;
2989 old_dir->i_ctime = old_dir->i_mtime =
2990 new_dir->i_ctime = new_dir->i_mtime =
2991 inode->i_ctime = current_time(old_dir);
2992 return 0;
2993}
2994
2995static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
2996{
2997 int error;
2998 int len;
2999 struct inode *inode;
3000 struct page *page;
3001
3002 len = strlen(symname) + 1;
3003 if (len > PAGE_SIZE)
3004 return -ENAMETOOLONG;
3005
3006 inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK | 0777, 0,
3007 VM_NORESERVE);
3008 if (!inode)
3009 return -ENOSPC;
3010
3011 error = security_inode_init_security(inode, dir, &dentry->d_name,
3012 shmem_initxattrs, NULL);
3013 if (error) {
3014 if (error != -EOPNOTSUPP) {
3015 iput(inode);
3016 return error;
3017 }
3018 error = 0;
3019 }
3020
3021 inode->i_size = len-1;
3022 if (len <= SHORT_SYMLINK_LEN) {
3023 inode->i_link = kmemdup(symname, len, GFP_KERNEL);
3024 if (!inode->i_link) {
3025 iput(inode);
3026 return -ENOMEM;
3027 }
3028 inode->i_op = &shmem_short_symlink_operations;
3029 } else {
3030 inode_nohighmem(inode);
3031 error = shmem_getpage(inode, 0, &page, SGP_WRITE);
3032 if (error) {
3033 iput(inode);
3034 return error;
3035 }
3036 inode->i_mapping->a_ops = &shmem_aops;
3037 inode->i_op = &shmem_symlink_inode_operations;
3038 memcpy(page_address(page), symname, len);
3039 SetPageUptodate(page);
3040 set_page_dirty(page);
3041 unlock_page(page);
3042 put_page(page);
3043 }
3044 dir->i_size += BOGO_DIRENT_SIZE;
3045 dir->i_ctime = dir->i_mtime = current_time(dir);
3046 d_instantiate(dentry, inode);
3047 dget(dentry);
3048 return 0;
3049}
3050
3051static void shmem_put_link(void *arg)
3052{
3053 mark_page_accessed(arg);
3054 put_page(arg);
3055}
3056
3057static const char *shmem_get_link(struct dentry *dentry,
3058 struct inode *inode,
3059 struct delayed_call *done)
3060{
3061 struct page *page = NULL;
3062 int error;
3063 if (!dentry) {
3064 page = find_get_page(inode->i_mapping, 0);
3065 if (!page)
3066 return ERR_PTR(-ECHILD);
3067 if (!PageUptodate(page)) {
3068 put_page(page);
3069 return ERR_PTR(-ECHILD);
3070 }
3071 } else {
3072 error = shmem_getpage(inode, 0, &page, SGP_READ);
3073 if (error)
3074 return ERR_PTR(error);
3075 unlock_page(page);
3076 }
3077 set_delayed_call(done, shmem_put_link, page);
3078 return page_address(page);
3079}
3080
3081#ifdef CONFIG_TMPFS_XATTR
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092static int shmem_initxattrs(struct inode *inode,
3093 const struct xattr *xattr_array,
3094 void *fs_info)
3095{
3096 struct shmem_inode_info *info = SHMEM_I(inode);
3097 const struct xattr *xattr;
3098 struct simple_xattr *new_xattr;
3099 size_t len;
3100
3101 for (xattr = xattr_array; xattr->name != NULL; xattr++) {
3102 new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
3103 if (!new_xattr)
3104 return -ENOMEM;
3105
3106 len = strlen(xattr->name) + 1;
3107 new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
3108 GFP_KERNEL);
3109 if (!new_xattr->name) {
3110 kfree(new_xattr);
3111 return -ENOMEM;
3112 }
3113
3114 memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
3115 XATTR_SECURITY_PREFIX_LEN);
3116 memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
3117 xattr->name, len);
3118
3119 simple_xattr_list_add(&info->xattrs, new_xattr);
3120 }
3121
3122 return 0;
3123}
3124
3125static int shmem_xattr_handler_get(const struct xattr_handler *handler,
3126 struct dentry *unused, struct inode *inode,
3127 const char *name, void *buffer, size_t size)
3128{
3129 struct shmem_inode_info *info = SHMEM_I(inode);
3130
3131 name = xattr_full_name(handler, name);
3132 return simple_xattr_get(&info->xattrs, name, buffer, size);
3133}
3134
3135static int shmem_xattr_handler_set(const struct xattr_handler *handler,
3136 struct dentry *unused, struct inode *inode,
3137 const char *name, const void *value,
3138 size_t size, int flags)
3139{
3140 struct shmem_inode_info *info = SHMEM_I(inode);
3141
3142 name = xattr_full_name(handler, name);
3143 return simple_xattr_set(&info->xattrs, name, value, size, flags);
3144}
3145
3146static const struct xattr_handler shmem_security_xattr_handler = {
3147 .prefix = XATTR_SECURITY_PREFIX,
3148 .get = shmem_xattr_handler_get,
3149 .set = shmem_xattr_handler_set,
3150};
3151
3152static const struct xattr_handler shmem_trusted_xattr_handler = {
3153 .prefix = XATTR_TRUSTED_PREFIX,
3154 .get = shmem_xattr_handler_get,
3155 .set = shmem_xattr_handler_set,
3156};
3157
3158static const struct xattr_handler *shmem_xattr_handlers[] = {
3159#ifdef CONFIG_TMPFS_POSIX_ACL
3160 &posix_acl_access_xattr_handler,
3161 &posix_acl_default_xattr_handler,
3162#endif
3163 &shmem_security_xattr_handler,
3164 &shmem_trusted_xattr_handler,
3165 NULL
3166};
3167
3168static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
3169{
3170 struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
3171 return simple_xattr_list(d_inode(dentry), &info->xattrs, buffer, size);
3172}
3173#endif
3174
3175static const struct inode_operations shmem_short_symlink_operations = {
3176 .get_link = simple_get_link,
3177#ifdef CONFIG_TMPFS_XATTR
3178 .listxattr = shmem_listxattr,
3179#endif
3180};
3181
3182static const struct inode_operations shmem_symlink_inode_operations = {
3183 .get_link = shmem_get_link,
3184#ifdef CONFIG_TMPFS_XATTR
3185 .listxattr = shmem_listxattr,
3186#endif
3187};
3188
3189static struct dentry *shmem_get_parent(struct dentry *child)
3190{
3191 return ERR_PTR(-ESTALE);
3192}
3193
3194static int shmem_match(struct inode *ino, void *vfh)
3195{
3196 __u32 *fh = vfh;
3197 __u64 inum = fh[2];
3198 inum = (inum << 32) | fh[1];
3199 return ino->i_ino == inum && fh[0] == ino->i_generation;
3200}
3201
3202
3203static struct dentry *shmem_find_alias(struct inode *inode)
3204{
3205 struct dentry *alias = d_find_alias(inode);
3206
3207 return alias ?: d_find_any_alias(inode);
3208}
3209
3210
3211static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
3212 struct fid *fid, int fh_len, int fh_type)
3213{
3214 struct inode *inode;
3215 struct dentry *dentry = NULL;
3216 u64 inum;
3217
3218 if (fh_len < 3)
3219 return NULL;
3220
3221 inum = fid->raw[2];
3222 inum = (inum << 32) | fid->raw[1];
3223
3224 inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
3225 shmem_match, fid->raw);
3226 if (inode) {
3227 dentry = shmem_find_alias(inode);
3228 iput(inode);
3229 }
3230
3231 return dentry;
3232}
3233
3234static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len,
3235 struct inode *parent)
3236{
3237 if (*len < 3) {
3238 *len = 3;
3239 return FILEID_INVALID;
3240 }
3241
3242 if (inode_unhashed(inode)) {
3243
3244
3245
3246
3247
3248 static DEFINE_SPINLOCK(lock);
3249 spin_lock(&lock);
3250 if (inode_unhashed(inode))
3251 __insert_inode_hash(inode,
3252 inode->i_ino + inode->i_generation);
3253 spin_unlock(&lock);
3254 }
3255
3256 fh[0] = inode->i_generation;
3257 fh[1] = inode->i_ino;
3258 fh[2] = ((__u64)inode->i_ino) >> 32;
3259
3260 *len = 3;
3261 return 1;
3262}
3263
3264static const struct export_operations shmem_export_ops = {
3265 .get_parent = shmem_get_parent,
3266 .encode_fh = shmem_encode_fh,
3267 .fh_to_dentry = shmem_fh_to_dentry,
3268};
3269
3270static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
3271 bool remount)
3272{
3273 char *this_char, *value, *rest;
3274 struct mempolicy *mpol = NULL;
3275 uid_t uid;
3276 gid_t gid;
3277
3278 while (options != NULL) {
3279 this_char = options;
3280 for (;;) {
3281
3282
3283
3284
3285
3286 options = strchr(options, ',');
3287 if (options == NULL)
3288 break;
3289 options++;
3290 if (!isdigit(*options)) {
3291 options[-1] = '\0';
3292 break;
3293 }
3294 }
3295 if (!*this_char)
3296 continue;
3297 if ((value = strchr(this_char,'=')) != NULL) {
3298 *value++ = 0;
3299 } else {
3300 pr_err("tmpfs: No value for mount option '%s'\n",
3301 this_char);
3302 goto error;
3303 }
3304
3305 if (!strcmp(this_char,"size")) {
3306 unsigned long long size;
3307 size = memparse(value,&rest);
3308 if (*rest == '%') {
3309 size <<= PAGE_SHIFT;
3310 size *= totalram_pages();
3311 do_div(size, 100);
3312 rest++;
3313 }
3314 if (*rest)
3315 goto bad_val;
3316 sbinfo->max_blocks =
3317 DIV_ROUND_UP(size, PAGE_SIZE);
3318 } else if (!strcmp(this_char,"nr_blocks")) {
3319 sbinfo->max_blocks = memparse(value, &rest);
3320 if (*rest)
3321 goto bad_val;
3322 } else if (!strcmp(this_char,"nr_inodes")) {
3323 sbinfo->max_inodes = memparse(value, &rest);
3324 if (*rest)
3325 goto bad_val;
3326 } else if (!strcmp(this_char,"mode")) {
3327 if (remount)
3328 continue;
3329 sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
3330 if (*rest)
3331 goto bad_val;
3332 } else if (!strcmp(this_char,"uid")) {
3333 if (remount)
3334 continue;
3335 uid = simple_strtoul(value, &rest, 0);
3336 if (*rest)
3337 goto bad_val;
3338 sbinfo->uid = make_kuid(current_user_ns(), uid);
3339 if (!uid_valid(sbinfo->uid))
3340 goto bad_val;
3341 } else if (!strcmp(this_char,"gid")) {
3342 if (remount)
3343 continue;
3344 gid = simple_strtoul(value, &rest, 0);
3345 if (*rest)
3346 goto bad_val;
3347 sbinfo->gid = make_kgid(current_user_ns(), gid);
3348 if (!gid_valid(sbinfo->gid))
3349 goto bad_val;
3350#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3351 } else if (!strcmp(this_char, "huge")) {
3352 int huge;
3353 huge = shmem_parse_huge(value);
3354 if (huge < 0)
3355 goto bad_val;
3356 if (!has_transparent_hugepage() &&
3357 huge != SHMEM_HUGE_NEVER)
3358 goto bad_val;
3359 sbinfo->huge = huge;
3360#endif
3361#ifdef CONFIG_NUMA
3362 } else if (!strcmp(this_char,"mpol")) {
3363 mpol_put(mpol);
3364 mpol = NULL;
3365 if (mpol_parse_str(value, &mpol))
3366 goto bad_val;
3367#endif
3368 } else {
3369 pr_err("tmpfs: Bad mount option %s\n", this_char);
3370 goto error;
3371 }
3372 }
3373 sbinfo->mpol = mpol;
3374 return 0;
3375
3376bad_val:
3377 pr_err("tmpfs: Bad value '%s' for mount option '%s'\n",
3378 value, this_char);
3379error:
3380 mpol_put(mpol);
3381 return 1;
3382
3383}
3384
3385static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
3386{
3387 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
3388 struct shmem_sb_info config = *sbinfo;
3389 unsigned long inodes;
3390 int error = -EINVAL;
3391
3392 config.mpol = NULL;
3393 if (shmem_parse_options(data, &config, true))
3394 return error;
3395
3396 spin_lock(&sbinfo->stat_lock);
3397 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
3398 if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0)
3399 goto out;
3400 if (config.max_inodes < inodes)
3401 goto out;
3402
3403
3404
3405
3406
3407 if (config.max_blocks && !sbinfo->max_blocks)
3408 goto out;
3409 if (config.max_inodes && !sbinfo->max_inodes)
3410 goto out;
3411
3412 error = 0;
3413 sbinfo->huge = config.huge;
3414 sbinfo->max_blocks = config.max_blocks;
3415 sbinfo->max_inodes = config.max_inodes;
3416 sbinfo->free_inodes = config.max_inodes - inodes;
3417
3418
3419
3420
3421 if (config.mpol) {
3422 mpol_put(sbinfo->mpol);
3423 sbinfo->mpol = config.mpol;
3424 }
3425out:
3426 spin_unlock(&sbinfo->stat_lock);
3427 return error;
3428}
3429
3430static int shmem_show_options(struct seq_file *seq, struct dentry *root)
3431{
3432 struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb);
3433
3434 if (sbinfo->max_blocks != shmem_default_max_blocks())
3435 seq_printf(seq, ",size=%luk",
3436 sbinfo->max_blocks << (PAGE_SHIFT - 10));
3437 if (sbinfo->max_inodes != shmem_default_max_inodes())
3438 seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
3439 if (sbinfo->mode != (0777 | S_ISVTX))
3440 seq_printf(seq, ",mode=%03ho", sbinfo->mode);
3441 if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
3442 seq_printf(seq, ",uid=%u",
3443 from_kuid_munged(&init_user_ns, sbinfo->uid));
3444 if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
3445 seq_printf(seq, ",gid=%u",
3446 from_kgid_munged(&init_user_ns, sbinfo->gid));
3447#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3448
3449 if (sbinfo->huge)
3450 seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge));
3451#endif
3452 shmem_show_mpol(seq, sbinfo->mpol);
3453 return 0;
3454}
3455
3456#endif
3457
3458static void shmem_put_super(struct super_block *sb)
3459{
3460 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
3461
3462 percpu_counter_destroy(&sbinfo->used_blocks);
3463 mpol_put(sbinfo->mpol);
3464 kfree(sbinfo);
3465 sb->s_fs_info = NULL;
3466}
3467
3468int shmem_fill_super(struct super_block *sb, void *data, int silent)
3469{
3470 struct inode *inode;
3471 struct shmem_sb_info *sbinfo;
3472 int err = -ENOMEM;
3473
3474
3475 sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info),
3476 L1_CACHE_BYTES), GFP_KERNEL);
3477 if (!sbinfo)
3478 return -ENOMEM;
3479
3480 sbinfo->mode = 0777 | S_ISVTX;
3481 sbinfo->uid = current_fsuid();
3482 sbinfo->gid = current_fsgid();
3483 sb->s_fs_info = sbinfo;
3484
3485#ifdef CONFIG_TMPFS
3486
3487
3488
3489
3490
3491 if (!(sb->s_flags & SB_KERNMOUNT)) {
3492 sbinfo->max_blocks = shmem_default_max_blocks();
3493 sbinfo->max_inodes = shmem_default_max_inodes();
3494 if (shmem_parse_options(data, sbinfo, false)) {
3495 err = -EINVAL;
3496 goto failed;
3497 }
3498 } else {
3499 sb->s_flags |= SB_NOUSER;
3500 }
3501 sb->s_export_op = &shmem_export_ops;
3502 sb->s_flags |= SB_NOSEC;
3503#else
3504 sb->s_flags |= SB_NOUSER;
3505#endif
3506
3507 spin_lock_init(&sbinfo->stat_lock);
3508 if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
3509 goto failed;
3510 sbinfo->free_inodes = sbinfo->max_inodes;
3511 spin_lock_init(&sbinfo->shrinklist_lock);
3512 INIT_LIST_HEAD(&sbinfo->shrinklist);
3513
3514 sb->s_maxbytes = MAX_LFS_FILESIZE;
3515 sb->s_blocksize = PAGE_SIZE;
3516 sb->s_blocksize_bits = PAGE_SHIFT;
3517 sb->s_magic = TMPFS_MAGIC;
3518 sb->s_op = &shmem_ops;
3519 sb->s_time_gran = 1;
3520#ifdef CONFIG_TMPFS_XATTR
3521 sb->s_xattr = shmem_xattr_handlers;
3522#endif
3523#ifdef CONFIG_TMPFS_POSIX_ACL
3524 sb->s_flags |= SB_POSIXACL;
3525#endif
3526 uuid_gen(&sb->s_uuid);
3527
3528 inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
3529 if (!inode)
3530 goto failed;
3531 inode->i_uid = sbinfo->uid;
3532 inode->i_gid = sbinfo->gid;
3533 sb->s_root = d_make_root(inode);
3534 if (!sb->s_root)
3535 goto failed;
3536 return 0;
3537
3538failed:
3539 shmem_put_super(sb);
3540 return err;
3541}
3542
3543static struct kmem_cache *shmem_inode_cachep;
3544
3545static struct inode *shmem_alloc_inode(struct super_block *sb)
3546{
3547 struct shmem_inode_info *info;
3548 info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
3549 if (!info)
3550 return NULL;
3551 return &info->vfs_inode;
3552}
3553
3554static void shmem_destroy_callback(struct rcu_head *head)
3555{
3556 struct inode *inode = container_of(head, struct inode, i_rcu);
3557 if (S_ISLNK(inode->i_mode))
3558 kfree(inode->i_link);
3559 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
3560}
3561
3562static void shmem_destroy_inode(struct inode *inode)
3563{
3564 if (S_ISREG(inode->i_mode))
3565 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
3566 call_rcu(&inode->i_rcu, shmem_destroy_callback);
3567}
3568
3569static void shmem_init_inode(void *foo)
3570{
3571 struct shmem_inode_info *info = foo;
3572 inode_init_once(&info->vfs_inode);
3573}
3574
3575static void shmem_init_inodecache(void)
3576{
3577 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
3578 sizeof(struct shmem_inode_info),
3579 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
3580}
3581
3582static void shmem_destroy_inodecache(void)
3583{
3584 kmem_cache_destroy(shmem_inode_cachep);
3585}
3586
3587static const struct address_space_operations shmem_aops = {
3588 .writepage = shmem_writepage,
3589 .set_page_dirty = __set_page_dirty_no_writeback,
3590#ifdef CONFIG_TMPFS
3591 .write_begin = shmem_write_begin,
3592 .write_end = shmem_write_end,
3593#endif
3594#ifdef CONFIG_MIGRATION
3595 .migratepage = migrate_page,
3596#endif
3597 .error_remove_page = generic_error_remove_page,
3598};
3599
3600static const struct file_operations shmem_file_operations = {
3601 .mmap = shmem_mmap,
3602 .get_unmapped_area = shmem_get_unmapped_area,
3603#ifdef CONFIG_TMPFS
3604 .llseek = shmem_file_llseek,
3605 .read_iter = shmem_file_read_iter,
3606 .write_iter = generic_file_write_iter,
3607 .fsync = noop_fsync,
3608 .splice_read = generic_file_splice_read,
3609 .splice_write = iter_file_splice_write,
3610 .fallocate = shmem_fallocate,
3611#endif
3612};
3613
3614static const struct inode_operations shmem_inode_operations = {
3615 .getattr = shmem_getattr,
3616 .setattr = shmem_setattr,
3617#ifdef CONFIG_TMPFS_XATTR
3618 .listxattr = shmem_listxattr,
3619 .set_acl = simple_set_acl,
3620#endif
3621};
3622
3623static const struct inode_operations shmem_dir_inode_operations = {
3624#ifdef CONFIG_TMPFS
3625 .create = shmem_create,
3626 .lookup = simple_lookup,
3627 .link = shmem_link,
3628 .unlink = shmem_unlink,
3629 .symlink = shmem_symlink,
3630 .mkdir = shmem_mkdir,
3631 .rmdir = shmem_rmdir,
3632 .mknod = shmem_mknod,
3633 .rename = shmem_rename2,
3634 .tmpfile = shmem_tmpfile,
3635#endif
3636#ifdef CONFIG_TMPFS_XATTR
3637 .listxattr = shmem_listxattr,
3638#endif
3639#ifdef CONFIG_TMPFS_POSIX_ACL
3640 .setattr = shmem_setattr,
3641 .set_acl = simple_set_acl,
3642#endif
3643};
3644
3645static const struct inode_operations shmem_special_inode_operations = {
3646#ifdef CONFIG_TMPFS_XATTR
3647 .listxattr = shmem_listxattr,
3648#endif
3649#ifdef CONFIG_TMPFS_POSIX_ACL
3650 .setattr = shmem_setattr,
3651 .set_acl = simple_set_acl,
3652#endif
3653};
3654
3655static const struct super_operations shmem_ops = {
3656 .alloc_inode = shmem_alloc_inode,
3657 .destroy_inode = shmem_destroy_inode,
3658#ifdef CONFIG_TMPFS
3659 .statfs = shmem_statfs,
3660 .remount_fs = shmem_remount_fs,
3661 .show_options = shmem_show_options,
3662#endif
3663 .evict_inode = shmem_evict_inode,
3664 .drop_inode = generic_delete_inode,
3665 .put_super = shmem_put_super,
3666#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3667 .nr_cached_objects = shmem_unused_huge_count,
3668 .free_cached_objects = shmem_unused_huge_scan,
3669#endif
3670};
3671
3672static const struct vm_operations_struct shmem_vm_ops = {
3673 .fault = shmem_fault,
3674 .map_pages = filemap_map_pages,
3675#ifdef CONFIG_NUMA
3676 .set_policy = shmem_set_policy,
3677 .get_policy = shmem_get_policy,
3678#endif
3679};
3680
3681static struct dentry *shmem_mount(struct file_system_type *fs_type,
3682 int flags, const char *dev_name, void *data)
3683{
3684 return mount_nodev(fs_type, flags, data, shmem_fill_super);
3685}
3686
3687static struct file_system_type shmem_fs_type = {
3688 .owner = THIS_MODULE,
3689 .name = "tmpfs",
3690 .mount = shmem_mount,
3691 .kill_sb = kill_litter_super,
3692 .fs_flags = FS_USERNS_MOUNT,
3693};
3694
3695int __init shmem_init(void)
3696{
3697 int error;
3698
3699
3700 if (shmem_inode_cachep)
3701 return 0;
3702
3703 shmem_init_inodecache();
3704
3705 error = register_filesystem(&shmem_fs_type);
3706 if (error) {
3707 pr_err("Could not register tmpfs\n");
3708 goto out2;
3709 }
3710
3711 shm_mnt = kern_mount(&shmem_fs_type);
3712 if (IS_ERR(shm_mnt)) {
3713 error = PTR_ERR(shm_mnt);
3714 pr_err("Could not kern_mount tmpfs\n");
3715 goto out1;
3716 }
3717
3718#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3719 if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
3720 SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
3721 else
3722 shmem_huge = 0;
3723#endif
3724 return 0;
3725
3726out1:
3727 unregister_filesystem(&shmem_fs_type);
3728out2:
3729 shmem_destroy_inodecache();
3730 shm_mnt = ERR_PTR(error);
3731 return error;
3732}
3733
3734#if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && defined(CONFIG_SYSFS)
3735static ssize_t shmem_enabled_show(struct kobject *kobj,
3736 struct kobj_attribute *attr, char *buf)
3737{
3738 int values[] = {
3739 SHMEM_HUGE_ALWAYS,
3740 SHMEM_HUGE_WITHIN_SIZE,
3741 SHMEM_HUGE_ADVISE,
3742 SHMEM_HUGE_NEVER,
3743 SHMEM_HUGE_DENY,
3744 SHMEM_HUGE_FORCE,
3745 };
3746 int i, count;
3747
3748 for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) {
3749 const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s ";
3750
3751 count += sprintf(buf + count, fmt,
3752 shmem_format_huge(values[i]));
3753 }
3754 buf[count - 1] = '\n';
3755 return count;
3756}
3757
3758static ssize_t shmem_enabled_store(struct kobject *kobj,
3759 struct kobj_attribute *attr, const char *buf, size_t count)
3760{
3761 char tmp[16];
3762 int huge;
3763
3764 if (count + 1 > sizeof(tmp))
3765 return -EINVAL;
3766 memcpy(tmp, buf, count);
3767 tmp[count] = '\0';
3768 if (count && tmp[count - 1] == '\n')
3769 tmp[count - 1] = '\0';
3770
3771 huge = shmem_parse_huge(tmp);
3772 if (huge == -EINVAL)
3773 return -EINVAL;
3774 if (!has_transparent_hugepage() &&
3775 huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
3776 return -EINVAL;
3777
3778 shmem_huge = huge;
3779 if (shmem_huge > SHMEM_HUGE_DENY)
3780 SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
3781 return count;
3782}
3783
3784struct kobj_attribute shmem_enabled_attr =
3785 __ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store);
3786#endif
3787
3788#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3789bool shmem_huge_enabled(struct vm_area_struct *vma)
3790{
3791 struct inode *inode = file_inode(vma->vm_file);
3792 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
3793 loff_t i_size;
3794 pgoff_t off;
3795
3796 if (shmem_huge == SHMEM_HUGE_FORCE)
3797 return true;
3798 if (shmem_huge == SHMEM_HUGE_DENY)
3799 return false;
3800 switch (sbinfo->huge) {
3801 case SHMEM_HUGE_NEVER:
3802 return false;
3803 case SHMEM_HUGE_ALWAYS:
3804 return true;
3805 case SHMEM_HUGE_WITHIN_SIZE:
3806 off = round_up(vma->vm_pgoff, HPAGE_PMD_NR);
3807 i_size = round_up(i_size_read(inode), PAGE_SIZE);
3808 if (i_size >= HPAGE_PMD_SIZE &&
3809 i_size >> PAGE_SHIFT >= off)
3810 return true;
3811
3812 case SHMEM_HUGE_ADVISE:
3813
3814 return (vma->vm_flags & VM_HUGEPAGE);
3815 default:
3816 VM_BUG_ON(1);
3817 return false;
3818 }
3819}
3820#endif
3821
3822#else
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833static struct file_system_type shmem_fs_type = {
3834 .name = "tmpfs",
3835 .mount = ramfs_mount,
3836 .kill_sb = kill_litter_super,
3837 .fs_flags = FS_USERNS_MOUNT,
3838};
3839
3840int __init shmem_init(void)
3841{
3842 BUG_ON(register_filesystem(&shmem_fs_type) != 0);
3843
3844 shm_mnt = kern_mount(&shmem_fs_type);
3845 BUG_ON(IS_ERR(shm_mnt));
3846
3847 return 0;
3848}
3849
3850int shmem_unuse(swp_entry_t swap, struct page *page)
3851{
3852 return 0;
3853}
3854
3855int shmem_lock(struct file *file, int lock, struct user_struct *user)
3856{
3857 return 0;
3858}
3859
3860void shmem_unlock_mapping(struct address_space *mapping)
3861{
3862}
3863
3864#ifdef CONFIG_MMU
3865unsigned long shmem_get_unmapped_area(struct file *file,
3866 unsigned long addr, unsigned long len,
3867 unsigned long pgoff, unsigned long flags)
3868{
3869 return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
3870}
3871#endif
3872
3873void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
3874{
3875 truncate_inode_pages_range(inode->i_mapping, lstart, lend);
3876}
3877EXPORT_SYMBOL_GPL(shmem_truncate_range);
3878
3879#define shmem_vm_ops generic_file_vm_ops
3880#define shmem_file_operations ramfs_file_operations
3881#define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
3882#define shmem_acct_size(flags, size) 0
3883#define shmem_unacct_size(flags, size) do {} while (0)
3884
3885#endif
3886
3887
3888
3889static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, loff_t size,
3890 unsigned long flags, unsigned int i_flags)
3891{
3892 struct inode *inode;
3893 struct file *res;
3894
3895 if (IS_ERR(mnt))
3896 return ERR_CAST(mnt);
3897
3898 if (size < 0 || size > MAX_LFS_FILESIZE)
3899 return ERR_PTR(-EINVAL);
3900
3901 if (shmem_acct_size(flags, size))
3902 return ERR_PTR(-ENOMEM);
3903
3904 inode = shmem_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0,
3905 flags);
3906 if (unlikely(!inode)) {
3907 shmem_unacct_size(flags, size);
3908 return ERR_PTR(-ENOSPC);
3909 }
3910 inode->i_flags |= i_flags;
3911 inode->i_size = size;
3912 clear_nlink(inode);
3913 res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
3914 if (!IS_ERR(res))
3915 res = alloc_file_pseudo(inode, mnt, name, O_RDWR,
3916 &shmem_file_operations);
3917 if (IS_ERR(res))
3918 iput(inode);
3919 return res;
3920}
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags)
3933{
3934 return __shmem_file_setup(shm_mnt, name, size, flags, S_PRIVATE);
3935}
3936
3937
3938
3939
3940
3941
3942
3943struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags)
3944{
3945 return __shmem_file_setup(shm_mnt, name, size, flags, 0);
3946}
3947EXPORT_SYMBOL_GPL(shmem_file_setup);
3948
3949
3950
3951
3952
3953
3954
3955
3956struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, const char *name,
3957 loff_t size, unsigned long flags)
3958{
3959 return __shmem_file_setup(mnt, name, size, flags, 0);
3960}
3961EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt);
3962
3963
3964
3965
3966
3967int shmem_zero_setup(struct vm_area_struct *vma)
3968{
3969 struct file *file;
3970 loff_t size = vma->vm_end - vma->vm_start;
3971
3972
3973
3974
3975
3976
3977
3978 file = shmem_kernel_file_setup("dev/zero", size, vma->vm_flags);
3979 if (IS_ERR(file))
3980 return PTR_ERR(file);
3981
3982 if (vma->vm_file)
3983 fput(vma->vm_file);
3984 vma->vm_file = file;
3985 vma->vm_ops = &shmem_vm_ops;
3986
3987 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) &&
3988 ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
3989 (vma->vm_end & HPAGE_PMD_MASK)) {
3990 khugepaged_enter(vma, vma->vm_flags);
3991 }
3992
3993 return 0;
3994}
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
4012 pgoff_t index, gfp_t gfp)
4013{
4014#ifdef CONFIG_SHMEM
4015 struct inode *inode = mapping->host;
4016 struct page *page;
4017 int error;
4018
4019 BUG_ON(mapping->a_ops != &shmem_aops);
4020 error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE,
4021 gfp, NULL, NULL, NULL);
4022 if (error)
4023 page = ERR_PTR(error);
4024 else
4025 unlock_page(page);
4026 return page;
4027#else
4028
4029
4030
4031 return read_cache_page_gfp(mapping, index, gfp);
4032#endif
4033}
4034EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp);
4035