2 * Resizable virtual memory filesystem for Linux.
4 * Copyright (C) 2000 Linus Torvalds.
6 * 2000-2001 Christoph Rohland
9 * Copyright (C) 2002-2011 Hugh Dickins.
10 * Copyright (C) 2011 Google Inc.
11 * Copyright (C) 2002-2005 VERITAS Software Corporation.
12 * Copyright (C) 2004 Andi Kleen, SuSE Labs
14 * Extended attribute support for tmpfs:
15 * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
16 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
19 * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
21 * This file is released under the GPL.
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>
32 #include <linux/random.h>
33 #include <linux/sched/signal.h>
34 #include <linux/export.h>
35 #include <linux/swap.h>
36 #include <linux/uio.h>
37 #include <linux/khugepaged.h>
38 #include <linux/hugetlb.h>
39 #include <linux/frontswap.h>
41 #include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */
43 static struct vfsmount
*shm_mnt
;
47 * This virtual memory filesystem is heavily based on the ramfs. It
48 * extends ramfs by the ability to use swap and honor resource limits
49 * which makes it a completely usable filesystem.
52 #include <linux/xattr.h>
53 #include <linux/exportfs.h>
54 #include <linux/posix_acl.h>
55 #include <linux/posix_acl_xattr.h>
56 #include <linux/mman.h>
57 #include <linux/string.h>
58 #include <linux/slab.h>
59 #include <linux/backing-dev.h>
60 #include <linux/shmem_fs.h>
61 #include <linux/writeback.h>
62 #include <linux/blkdev.h>
63 #include <linux/pagevec.h>
64 #include <linux/percpu_counter.h>
65 #include <linux/falloc.h>
66 #include <linux/splice.h>
67 #include <linux/security.h>
68 #include <linux/swapops.h>
69 #include <linux/mempolicy.h>
70 #include <linux/namei.h>
71 #include <linux/ctype.h>
72 #include <linux/migrate.h>
73 #include <linux/highmem.h>
74 #include <linux/seq_file.h>
75 #include <linux/magic.h>
76 #include <linux/syscalls.h>
77 #include <linux/fcntl.h>
78 #include <uapi/linux/memfd.h>
79 #include <linux/userfaultfd_k.h>
80 #include <linux/rmap.h>
81 #include <linux/uuid.h>
83 #include <linux/uaccess.h>
84 #include <asm/pgtable.h>
88 #define BLOCKS_PER_PAGE (PAGE_SIZE/512)
89 #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
91 /* Pretend that each entry is of this size in directory's i_size */
92 #define BOGO_DIRENT_SIZE 20
94 /* Symlink up to this size is kmalloc'ed instead of using a swappable page */
95 #define SHORT_SYMLINK_LEN 128
98 * shmem_fallocate communicates with shmem_fault or shmem_writepage via
99 * inode->i_private (with i_mutex making sure that it has only one user at
100 * a time): we would prefer not to enlarge the shmem inode just for that.
102 struct shmem_falloc
{
103 wait_queue_head_t
*waitq
; /* faults into hole wait for punch to end */
104 pgoff_t start
; /* start of range currently being fallocated */
105 pgoff_t next
; /* the next page offset to be fallocated */
106 pgoff_t nr_falloced
; /* how many new pages have been fallocated */
107 pgoff_t nr_unswapped
; /* how often writepage refused to swap out */
111 static unsigned long shmem_default_max_blocks(void)
113 return totalram_pages() / 2;
116 static unsigned long shmem_default_max_inodes(void)
118 unsigned long nr_pages
= totalram_pages();
120 return min(nr_pages
- totalhigh_pages(), nr_pages
/ 2);
124 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
);
125 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
126 struct shmem_inode_info
*info
, pgoff_t index
);
127 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
128 struct page
**pagep
, enum sgp_type sgp
,
129 gfp_t gfp
, struct vm_area_struct
*vma
,
130 vm_fault_t
*fault_type
);
131 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
132 struct page
**pagep
, enum sgp_type sgp
,
133 gfp_t gfp
, struct vm_area_struct
*vma
,
134 struct vm_fault
*vmf
, vm_fault_t
*fault_type
);
136 int shmem_getpage(struct inode
*inode
, pgoff_t index
,
137 struct page
**pagep
, enum sgp_type sgp
)
139 return shmem_getpage_gfp(inode
, index
, pagep
, sgp
,
140 mapping_gfp_mask(inode
->i_mapping
), NULL
, NULL
, NULL
);
143 static inline struct shmem_sb_info
*SHMEM_SB(struct super_block
*sb
)
145 return sb
->s_fs_info
;
149 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
150 * for shared memory and for shared anonymous (/dev/zero) mappings
151 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
152 * consistent with the pre-accounting of private mappings ...
154 static inline int shmem_acct_size(unsigned long flags
, loff_t size
)
156 return (flags
& VM_NORESERVE
) ?
157 0 : security_vm_enough_memory_mm(current
->mm
, VM_ACCT(size
));
160 static inline void shmem_unacct_size(unsigned long flags
, loff_t size
)
162 if (!(flags
& VM_NORESERVE
))
163 vm_unacct_memory(VM_ACCT(size
));
166 static inline int shmem_reacct_size(unsigned long flags
,
167 loff_t oldsize
, loff_t newsize
)
169 if (!(flags
& VM_NORESERVE
)) {
170 if (VM_ACCT(newsize
) > VM_ACCT(oldsize
))
171 return security_vm_enough_memory_mm(current
->mm
,
172 VM_ACCT(newsize
) - VM_ACCT(oldsize
));
173 else if (VM_ACCT(newsize
) < VM_ACCT(oldsize
))
174 vm_unacct_memory(VM_ACCT(oldsize
) - VM_ACCT(newsize
));
180 * ... whereas tmpfs objects are accounted incrementally as
181 * pages are allocated, in order to allow large sparse files.
182 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
183 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
185 static inline int shmem_acct_block(unsigned long flags
, long pages
)
187 if (!(flags
& VM_NORESERVE
))
190 return security_vm_enough_memory_mm(current
->mm
,
191 pages
* VM_ACCT(PAGE_SIZE
));
194 static inline void shmem_unacct_blocks(unsigned long flags
, long pages
)
196 if (flags
& VM_NORESERVE
)
197 vm_unacct_memory(pages
* VM_ACCT(PAGE_SIZE
));
200 static inline bool shmem_inode_acct_block(struct inode
*inode
, long pages
)
202 struct shmem_inode_info
*info
= SHMEM_I(inode
);
203 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
205 if (shmem_acct_block(info
->flags
, pages
))
208 if (sbinfo
->max_blocks
) {
209 if (percpu_counter_compare(&sbinfo
->used_blocks
,
210 sbinfo
->max_blocks
- pages
) > 0)
212 percpu_counter_add(&sbinfo
->used_blocks
, pages
);
218 shmem_unacct_blocks(info
->flags
, pages
);
222 static inline void shmem_inode_unacct_blocks(struct inode
*inode
, long pages
)
224 struct shmem_inode_info
*info
= SHMEM_I(inode
);
225 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
227 if (sbinfo
->max_blocks
)
228 percpu_counter_sub(&sbinfo
->used_blocks
, pages
);
229 shmem_unacct_blocks(info
->flags
, pages
);
232 static const struct super_operations shmem_ops
;
233 static const struct address_space_operations shmem_aops
;
234 static const struct file_operations shmem_file_operations
;
235 static const struct inode_operations shmem_inode_operations
;
236 static const struct inode_operations shmem_dir_inode_operations
;
237 static const struct inode_operations shmem_special_inode_operations
;
238 static const struct vm_operations_struct shmem_vm_ops
;
239 static struct file_system_type shmem_fs_type
;
241 bool vma_is_shmem(struct vm_area_struct
*vma
)
243 return vma
->vm_ops
== &shmem_vm_ops
;
246 static LIST_HEAD(shmem_swaplist
);
247 static DEFINE_MUTEX(shmem_swaplist_mutex
);
249 static int shmem_reserve_inode(struct super_block
*sb
)
251 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
252 if (sbinfo
->max_inodes
) {
253 spin_lock(&sbinfo
->stat_lock
);
254 if (!sbinfo
->free_inodes
) {
255 spin_unlock(&sbinfo
->stat_lock
);
258 sbinfo
->free_inodes
--;
259 spin_unlock(&sbinfo
->stat_lock
);
264 static void shmem_free_inode(struct super_block
*sb
)
266 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
267 if (sbinfo
->max_inodes
) {
268 spin_lock(&sbinfo
->stat_lock
);
269 sbinfo
->free_inodes
++;
270 spin_unlock(&sbinfo
->stat_lock
);
275 * shmem_recalc_inode - recalculate the block usage of an inode
276 * @inode: inode to recalc
278 * We have to calculate the free blocks since the mm can drop
279 * undirtied hole pages behind our back.
281 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
282 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
284 * It has to be called with the spinlock held.
286 static void shmem_recalc_inode(struct inode
*inode
)
288 struct shmem_inode_info
*info
= SHMEM_I(inode
);
291 freed
= info
->alloced
- info
->swapped
- inode
->i_mapping
->nrpages
;
293 info
->alloced
-= freed
;
294 inode
->i_blocks
-= freed
* BLOCKS_PER_PAGE
;
295 shmem_inode_unacct_blocks(inode
, freed
);
299 bool shmem_charge(struct inode
*inode
, long pages
)
301 struct shmem_inode_info
*info
= SHMEM_I(inode
);
304 if (!shmem_inode_acct_block(inode
, pages
))
307 /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
308 inode
->i_mapping
->nrpages
+= pages
;
310 spin_lock_irqsave(&info
->lock
, flags
);
311 info
->alloced
+= pages
;
312 inode
->i_blocks
+= pages
* BLOCKS_PER_PAGE
;
313 shmem_recalc_inode(inode
);
314 spin_unlock_irqrestore(&info
->lock
, flags
);
319 void shmem_uncharge(struct inode
*inode
, long pages
)
321 struct shmem_inode_info
*info
= SHMEM_I(inode
);
324 /* nrpages adjustment done by __delete_from_page_cache() or caller */
326 spin_lock_irqsave(&info
->lock
, flags
);
327 info
->alloced
-= pages
;
328 inode
->i_blocks
-= pages
* BLOCKS_PER_PAGE
;
329 shmem_recalc_inode(inode
);
330 spin_unlock_irqrestore(&info
->lock
, flags
);
332 shmem_inode_unacct_blocks(inode
, pages
);
336 * Replace item expected in xarray by a new item, while holding xa_lock.
338 static int shmem_replace_entry(struct address_space
*mapping
,
339 pgoff_t index
, void *expected
, void *replacement
)
341 XA_STATE(xas
, &mapping
->i_pages
, index
);
344 VM_BUG_ON(!expected
);
345 VM_BUG_ON(!replacement
);
346 item
= xas_load(&xas
);
347 if (item
!= expected
)
349 xas_store(&xas
, replacement
);
354 * Sometimes, before we decide whether to proceed or to fail, we must check
355 * that an entry was not already brought back from swap by a racing thread.
357 * Checking page is not enough: by the time a SwapCache page is locked, it
358 * might be reused, and again be SwapCache, using the same swap as before.
360 static bool shmem_confirm_swap(struct address_space
*mapping
,
361 pgoff_t index
, swp_entry_t swap
)
363 return xa_load(&mapping
->i_pages
, index
) == swp_to_radix_entry(swap
);
367 * Definitions for "huge tmpfs": tmpfs mounted with the huge= option
370 * disables huge pages for the mount;
372 * enables huge pages for the mount;
373 * SHMEM_HUGE_WITHIN_SIZE:
374 * only allocate huge pages if the page will be fully within i_size,
375 * also respect fadvise()/madvise() hints;
377 * only allocate huge pages if requested with fadvise()/madvise();
380 #define SHMEM_HUGE_NEVER 0
381 #define SHMEM_HUGE_ALWAYS 1
382 #define SHMEM_HUGE_WITHIN_SIZE 2
383 #define SHMEM_HUGE_ADVISE 3
387 * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
390 * disables huge on shm_mnt and all mounts, for emergency use;
392 * enables huge on shm_mnt and all mounts, w/o needing option, for testing;
395 #define SHMEM_HUGE_DENY (-1)
396 #define SHMEM_HUGE_FORCE (-2)
398 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
399 /* ifdef here to avoid bloating shmem.o when not necessary */
401 static int shmem_huge __read_mostly
;
403 #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
404 static int shmem_parse_huge(const char *str
)
406 if (!strcmp(str
, "never"))
407 return SHMEM_HUGE_NEVER
;
408 if (!strcmp(str
, "always"))
409 return SHMEM_HUGE_ALWAYS
;
410 if (!strcmp(str
, "within_size"))
411 return SHMEM_HUGE_WITHIN_SIZE
;
412 if (!strcmp(str
, "advise"))
413 return SHMEM_HUGE_ADVISE
;
414 if (!strcmp(str
, "deny"))
415 return SHMEM_HUGE_DENY
;
416 if (!strcmp(str
, "force"))
417 return SHMEM_HUGE_FORCE
;
421 static const char *shmem_format_huge(int huge
)
424 case SHMEM_HUGE_NEVER
:
426 case SHMEM_HUGE_ALWAYS
:
428 case SHMEM_HUGE_WITHIN_SIZE
:
429 return "within_size";
430 case SHMEM_HUGE_ADVISE
:
432 case SHMEM_HUGE_DENY
:
434 case SHMEM_HUGE_FORCE
:
443 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
444 struct shrink_control
*sc
, unsigned long nr_to_split
)
446 LIST_HEAD(list
), *pos
, *next
;
447 LIST_HEAD(to_remove
);
449 struct shmem_inode_info
*info
;
451 unsigned long batch
= sc
? sc
->nr_to_scan
: 128;
452 int removed
= 0, split
= 0;
454 if (list_empty(&sbinfo
->shrinklist
))
457 spin_lock(&sbinfo
->shrinklist_lock
);
458 list_for_each_safe(pos
, next
, &sbinfo
->shrinklist
) {
459 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
462 inode
= igrab(&info
->vfs_inode
);
464 /* inode is about to be evicted */
466 list_del_init(&info
->shrinklist
);
471 /* Check if there's anything to gain */
472 if (round_up(inode
->i_size
, PAGE_SIZE
) ==
473 round_up(inode
->i_size
, HPAGE_PMD_SIZE
)) {
474 list_move(&info
->shrinklist
, &to_remove
);
479 list_move(&info
->shrinklist
, &list
);
484 spin_unlock(&sbinfo
->shrinklist_lock
);
486 list_for_each_safe(pos
, next
, &to_remove
) {
487 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
488 inode
= &info
->vfs_inode
;
489 list_del_init(&info
->shrinklist
);
493 list_for_each_safe(pos
, next
, &list
) {
496 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
497 inode
= &info
->vfs_inode
;
499 if (nr_to_split
&& split
>= nr_to_split
)
502 page
= find_get_page(inode
->i_mapping
,
503 (inode
->i_size
& HPAGE_PMD_MASK
) >> PAGE_SHIFT
);
507 /* No huge page at the end of the file: nothing to split */
508 if (!PageTransHuge(page
)) {
514 * Leave the inode on the list if we failed to lock
515 * the page at this time.
517 * Waiting for the lock may lead to deadlock in the
520 if (!trylock_page(page
)) {
525 ret
= split_huge_page(page
);
529 /* If split failed leave the inode on the list */
535 list_del_init(&info
->shrinklist
);
541 spin_lock(&sbinfo
->shrinklist_lock
);
542 list_splice_tail(&list
, &sbinfo
->shrinklist
);
543 sbinfo
->shrinklist_len
-= removed
;
544 spin_unlock(&sbinfo
->shrinklist_lock
);
549 static long shmem_unused_huge_scan(struct super_block
*sb
,
550 struct shrink_control
*sc
)
552 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
554 if (!READ_ONCE(sbinfo
->shrinklist_len
))
557 return shmem_unused_huge_shrink(sbinfo
, sc
, 0);
560 static long shmem_unused_huge_count(struct super_block
*sb
,
561 struct shrink_control
*sc
)
563 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
564 return READ_ONCE(sbinfo
->shrinklist_len
);
566 #else /* !CONFIG_TRANSPARENT_HUGE_PAGECACHE */
568 #define shmem_huge SHMEM_HUGE_DENY
570 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
571 struct shrink_control
*sc
, unsigned long nr_to_split
)
575 #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */
577 static inline bool is_huge_enabled(struct shmem_sb_info
*sbinfo
)
579 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
) &&
580 (shmem_huge
== SHMEM_HUGE_FORCE
|| sbinfo
->huge
) &&
581 shmem_huge
!= SHMEM_HUGE_DENY
)
587 * Like add_to_page_cache_locked, but error if expected item has gone.
589 static int shmem_add_to_page_cache(struct page
*page
,
590 struct address_space
*mapping
,
591 pgoff_t index
, void *expected
, gfp_t gfp
)
593 XA_STATE_ORDER(xas
, &mapping
->i_pages
, index
, compound_order(page
));
595 unsigned long nr
= 1UL << compound_order(page
);
597 VM_BUG_ON_PAGE(PageTail(page
), page
);
598 VM_BUG_ON_PAGE(index
!= round_down(index
, nr
), page
);
599 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
600 VM_BUG_ON_PAGE(!PageSwapBacked(page
), page
);
601 VM_BUG_ON(expected
&& PageTransHuge(page
));
603 page_ref_add(page
, nr
);
604 page
->mapping
= mapping
;
610 entry
= xas_find_conflict(&xas
);
611 if (entry
!= expected
)
612 xas_set_err(&xas
, -EEXIST
);
613 xas_create_range(&xas
);
617 xas_store(&xas
, page
+ i
);
622 if (PageTransHuge(page
)) {
623 count_vm_event(THP_FILE_ALLOC
);
624 __inc_node_page_state(page
, NR_SHMEM_THPS
);
626 mapping
->nrpages
+= nr
;
627 __mod_node_page_state(page_pgdat(page
), NR_FILE_PAGES
, nr
);
628 __mod_node_page_state(page_pgdat(page
), NR_SHMEM
, nr
);
630 xas_unlock_irq(&xas
);
631 } while (xas_nomem(&xas
, gfp
));
633 if (xas_error(&xas
)) {
634 page
->mapping
= NULL
;
635 page_ref_sub(page
, nr
);
636 return xas_error(&xas
);
643 * Like delete_from_page_cache, but substitutes swap for page.
645 static void shmem_delete_from_page_cache(struct page
*page
, void *radswap
)
647 struct address_space
*mapping
= page
->mapping
;
650 VM_BUG_ON_PAGE(PageCompound(page
), page
);
652 xa_lock_irq(&mapping
->i_pages
);
653 error
= shmem_replace_entry(mapping
, page
->index
, page
, radswap
);
654 page
->mapping
= NULL
;
656 __dec_node_page_state(page
, NR_FILE_PAGES
);
657 __dec_node_page_state(page
, NR_SHMEM
);
658 xa_unlock_irq(&mapping
->i_pages
);
664 * Remove swap entry from page cache, free the swap and its page cache.
666 static int shmem_free_swap(struct address_space
*mapping
,
667 pgoff_t index
, void *radswap
)
671 old
= xa_cmpxchg_irq(&mapping
->i_pages
, index
, radswap
, NULL
, 0);
674 free_swap_and_cache(radix_to_swp_entry(radswap
));
679 * Determine (in bytes) how many of the shmem object's pages mapped by the
680 * given offsets are swapped out.
682 * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
683 * as long as the inode doesn't go away and racy results are not a problem.
685 unsigned long shmem_partial_swap_usage(struct address_space
*mapping
,
686 pgoff_t start
, pgoff_t end
)
688 XA_STATE(xas
, &mapping
->i_pages
, start
);
690 unsigned long swapped
= 0;
693 xas_for_each(&xas
, page
, end
- 1) {
694 if (xas_retry(&xas
, page
))
696 if (xa_is_value(page
))
699 if (need_resched()) {
707 return swapped
<< PAGE_SHIFT
;
711 * Determine (in bytes) how many of the shmem object's pages mapped by the
712 * given vma is swapped out.
714 * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
715 * as long as the inode doesn't go away and racy results are not a problem.
717 unsigned long shmem_swap_usage(struct vm_area_struct
*vma
)
719 struct inode
*inode
= file_inode(vma
->vm_file
);
720 struct shmem_inode_info
*info
= SHMEM_I(inode
);
721 struct address_space
*mapping
= inode
->i_mapping
;
722 unsigned long swapped
;
724 /* Be careful as we don't hold info->lock */
725 swapped
= READ_ONCE(info
->swapped
);
728 * The easier cases are when the shmem object has nothing in swap, or
729 * the vma maps it whole. Then we can simply use the stats that we
735 if (!vma
->vm_pgoff
&& vma
->vm_end
- vma
->vm_start
>= inode
->i_size
)
736 return swapped
<< PAGE_SHIFT
;
738 /* Here comes the more involved part */
739 return shmem_partial_swap_usage(mapping
,
740 linear_page_index(vma
, vma
->vm_start
),
741 linear_page_index(vma
, vma
->vm_end
));
745 * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
747 void shmem_unlock_mapping(struct address_space
*mapping
)
750 pgoff_t indices
[PAGEVEC_SIZE
];
755 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
757 while (!mapping_unevictable(mapping
)) {
759 * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
760 * has finished, if it hits a row of PAGEVEC_SIZE swap entries.
762 pvec
.nr
= find_get_entries(mapping
, index
,
763 PAGEVEC_SIZE
, pvec
.pages
, indices
);
766 index
= indices
[pvec
.nr
- 1] + 1;
767 pagevec_remove_exceptionals(&pvec
);
768 check_move_unevictable_pages(&pvec
);
769 pagevec_release(&pvec
);
775 * Remove range of pages and swap entries from page cache, and free them.
776 * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
778 static void shmem_undo_range(struct inode
*inode
, loff_t lstart
, loff_t lend
,
781 struct address_space
*mapping
= inode
->i_mapping
;
782 struct shmem_inode_info
*info
= SHMEM_I(inode
);
783 pgoff_t start
= (lstart
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
784 pgoff_t end
= (lend
+ 1) >> PAGE_SHIFT
;
785 unsigned int partial_start
= lstart
& (PAGE_SIZE
- 1);
786 unsigned int partial_end
= (lend
+ 1) & (PAGE_SIZE
- 1);
788 pgoff_t indices
[PAGEVEC_SIZE
];
789 long nr_swaps_freed
= 0;
794 end
= -1; /* unsigned, so actually very big */
798 while (index
< end
) {
799 pvec
.nr
= find_get_entries(mapping
, index
,
800 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
801 pvec
.pages
, indices
);
804 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
805 struct page
*page
= pvec
.pages
[i
];
811 if (xa_is_value(page
)) {
814 nr_swaps_freed
+= !shmem_free_swap(mapping
,
819 VM_BUG_ON_PAGE(page_to_pgoff(page
) != index
, page
);
821 if (!trylock_page(page
))
824 if (PageTransTail(page
)) {
825 /* Middle of THP: zero out the page */
826 clear_highpage(page
);
829 } else if (PageTransHuge(page
)) {
830 if (index
== round_down(end
, HPAGE_PMD_NR
)) {
832 * Range ends in the middle of THP:
835 clear_highpage(page
);
839 index
+= HPAGE_PMD_NR
- 1;
840 i
+= HPAGE_PMD_NR
- 1;
843 if (!unfalloc
|| !PageUptodate(page
)) {
844 VM_BUG_ON_PAGE(PageTail(page
), page
);
845 if (page_mapping(page
) == mapping
) {
846 VM_BUG_ON_PAGE(PageWriteback(page
), page
);
847 truncate_inode_page(mapping
, page
);
852 pagevec_remove_exceptionals(&pvec
);
853 pagevec_release(&pvec
);
859 struct page
*page
= NULL
;
860 shmem_getpage(inode
, start
- 1, &page
, SGP_READ
);
862 unsigned int top
= PAGE_SIZE
;
867 zero_user_segment(page
, partial_start
, top
);
868 set_page_dirty(page
);
874 struct page
*page
= NULL
;
875 shmem_getpage(inode
, end
, &page
, SGP_READ
);
877 zero_user_segment(page
, 0, partial_end
);
878 set_page_dirty(page
);
887 while (index
< end
) {
890 pvec
.nr
= find_get_entries(mapping
, index
,
891 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
892 pvec
.pages
, indices
);
894 /* If all gone or hole-punch or unfalloc, we're done */
895 if (index
== start
|| end
!= -1)
897 /* But if truncating, restart to make sure all gone */
901 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
902 struct page
*page
= pvec
.pages
[i
];
908 if (xa_is_value(page
)) {
911 if (shmem_free_swap(mapping
, index
, page
)) {
912 /* Swap was replaced by page: retry */
922 if (PageTransTail(page
)) {
923 /* Middle of THP: zero out the page */
924 clear_highpage(page
);
927 * Partial thp truncate due 'start' in middle
928 * of THP: don't need to look on these pages
929 * again on !pvec.nr restart.
931 if (index
!= round_down(end
, HPAGE_PMD_NR
))
934 } else if (PageTransHuge(page
)) {
935 if (index
== round_down(end
, HPAGE_PMD_NR
)) {
937 * Range ends in the middle of THP:
940 clear_highpage(page
);
944 index
+= HPAGE_PMD_NR
- 1;
945 i
+= HPAGE_PMD_NR
- 1;
948 if (!unfalloc
|| !PageUptodate(page
)) {
949 VM_BUG_ON_PAGE(PageTail(page
), page
);
950 if (page_mapping(page
) == mapping
) {
951 VM_BUG_ON_PAGE(PageWriteback(page
), page
);
952 truncate_inode_page(mapping
, page
);
954 /* Page was replaced by swap: retry */
962 pagevec_remove_exceptionals(&pvec
);
963 pagevec_release(&pvec
);
967 spin_lock_irq(&info
->lock
);
968 info
->swapped
-= nr_swaps_freed
;
969 shmem_recalc_inode(inode
);
970 spin_unlock_irq(&info
->lock
);
973 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
975 shmem_undo_range(inode
, lstart
, lend
, false);
976 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
978 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
980 static int shmem_getattr(const struct path
*path
, struct kstat
*stat
,
981 u32 request_mask
, unsigned int query_flags
)
983 struct inode
*inode
= path
->dentry
->d_inode
;
984 struct shmem_inode_info
*info
= SHMEM_I(inode
);
985 struct shmem_sb_info
*sb_info
= SHMEM_SB(inode
->i_sb
);
987 if (info
->alloced
- info
->swapped
!= inode
->i_mapping
->nrpages
) {
988 spin_lock_irq(&info
->lock
);
989 shmem_recalc_inode(inode
);
990 spin_unlock_irq(&info
->lock
);
992 generic_fillattr(inode
, stat
);
994 if (is_huge_enabled(sb_info
))
995 stat
->blksize
= HPAGE_PMD_SIZE
;
1000 static int shmem_setattr(struct dentry
*dentry
, struct iattr
*attr
)
1002 struct inode
*inode
= d_inode(dentry
);
1003 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1004 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
1007 error
= setattr_prepare(dentry
, attr
);
1011 if (S_ISREG(inode
->i_mode
) && (attr
->ia_valid
& ATTR_SIZE
)) {
1012 loff_t oldsize
= inode
->i_size
;
1013 loff_t newsize
= attr
->ia_size
;
1015 /* protected by i_mutex */
1016 if ((newsize
< oldsize
&& (info
->seals
& F_SEAL_SHRINK
)) ||
1017 (newsize
> oldsize
&& (info
->seals
& F_SEAL_GROW
)))
1020 if (newsize
!= oldsize
) {
1021 error
= shmem_reacct_size(SHMEM_I(inode
)->flags
,
1025 i_size_write(inode
, newsize
);
1026 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
1028 if (newsize
<= oldsize
) {
1029 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
1030 if (oldsize
> holebegin
)
1031 unmap_mapping_range(inode
->i_mapping
,
1034 shmem_truncate_range(inode
,
1035 newsize
, (loff_t
)-1);
1036 /* unmap again to remove racily COWed private pages */
1037 if (oldsize
> holebegin
)
1038 unmap_mapping_range(inode
->i_mapping
,
1042 * Part of the huge page can be beyond i_size: subject
1043 * to shrink under memory pressure.
1045 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
)) {
1046 spin_lock(&sbinfo
->shrinklist_lock
);
1048 * _careful to defend against unlocked access to
1049 * ->shrink_list in shmem_unused_huge_shrink()
1051 if (list_empty_careful(&info
->shrinklist
)) {
1052 list_add_tail(&info
->shrinklist
,
1053 &sbinfo
->shrinklist
);
1054 sbinfo
->shrinklist_len
++;
1056 spin_unlock(&sbinfo
->shrinklist_lock
);
1061 setattr_copy(inode
, attr
);
1062 if (attr
->ia_valid
& ATTR_MODE
)
1063 error
= posix_acl_chmod(inode
, inode
->i_mode
);
1067 static void shmem_evict_inode(struct inode
*inode
)
1069 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1070 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
1072 if (inode
->i_mapping
->a_ops
== &shmem_aops
) {
1073 shmem_unacct_size(info
->flags
, inode
->i_size
);
1075 shmem_truncate_range(inode
, 0, (loff_t
)-1);
1076 if (!list_empty(&info
->shrinklist
)) {
1077 spin_lock(&sbinfo
->shrinklist_lock
);
1078 if (!list_empty(&info
->shrinklist
)) {
1079 list_del_init(&info
->shrinklist
);
1080 sbinfo
->shrinklist_len
--;
1082 spin_unlock(&sbinfo
->shrinklist_lock
);
1084 if (!list_empty(&info
->swaplist
)) {
1085 mutex_lock(&shmem_swaplist_mutex
);
1086 list_del_init(&info
->swaplist
);
1087 mutex_unlock(&shmem_swaplist_mutex
);
1091 simple_xattrs_free(&info
->xattrs
);
1092 WARN_ON(inode
->i_blocks
);
1093 shmem_free_inode(inode
->i_sb
);
1097 extern struct swap_info_struct
*swap_info
[];
1099 static int shmem_find_swap_entries(struct address_space
*mapping
,
1100 pgoff_t start
, unsigned int nr_entries
,
1101 struct page
**entries
, pgoff_t
*indices
,
1104 XA_STATE(xas
, &mapping
->i_pages
, start
);
1106 unsigned int ret
= 0;
1112 xas_for_each(&xas
, page
, ULONG_MAX
) {
1113 if (xas_retry(&xas
, page
))
1116 if (!xa_is_value(page
))
1120 swp_entry_t entry
= radix_to_swp_entry(page
);
1122 if (!frontswap_test(swap_info
[swp_type(entry
)],
1127 indices
[ret
] = xas
.xa_index
;
1128 entries
[ret
] = page
;
1130 if (need_resched()) {
1134 if (++ret
== nr_entries
)
1143 * Move the swapped pages for an inode to page cache. Returns the count
1144 * of pages swapped in, or the error in case of failure.
1146 static int shmem_unuse_swap_entries(struct inode
*inode
, struct pagevec pvec
,
1152 struct address_space
*mapping
= inode
->i_mapping
;
1154 for (i
= 0; i
< pvec
.nr
; i
++) {
1155 struct page
*page
= pvec
.pages
[i
];
1157 if (!xa_is_value(page
))
1159 error
= shmem_swapin_page(inode
, indices
[i
],
1161 mapping_gfp_mask(mapping
),
1168 if (error
== -ENOMEM
)
1172 return error
? error
: ret
;
1176 * If swap found in inode, free it and move page from swapcache to filecache.
1178 static int shmem_unuse_inode(struct inode
*inode
, unsigned int type
,
1179 bool frontswap
, unsigned long *fs_pages_to_unuse
)
1181 struct address_space
*mapping
= inode
->i_mapping
;
1183 struct pagevec pvec
;
1184 pgoff_t indices
[PAGEVEC_SIZE
];
1185 bool frontswap_partial
= (frontswap
&& *fs_pages_to_unuse
> 0);
1188 pagevec_init(&pvec
);
1190 unsigned int nr_entries
= PAGEVEC_SIZE
;
1192 if (frontswap_partial
&& *fs_pages_to_unuse
< PAGEVEC_SIZE
)
1193 nr_entries
= *fs_pages_to_unuse
;
1195 pvec
.nr
= shmem_find_swap_entries(mapping
, start
, nr_entries
,
1196 pvec
.pages
, indices
,
1203 ret
= shmem_unuse_swap_entries(inode
, pvec
, indices
);
1207 if (frontswap_partial
) {
1208 *fs_pages_to_unuse
-= ret
;
1209 if (*fs_pages_to_unuse
== 0) {
1210 ret
= FRONTSWAP_PAGES_UNUSED
;
1215 start
= indices
[pvec
.nr
- 1];
1222 * Read all the shared memory data that resides in the swap
1223 * device 'type' back into memory, so the swap device can be
1226 int shmem_unuse(unsigned int type
, bool frontswap
,
1227 unsigned long *fs_pages_to_unuse
)
1229 struct shmem_inode_info
*info
, *next
;
1230 struct inode
*inode
;
1231 struct inode
*prev_inode
= NULL
;
1234 if (list_empty(&shmem_swaplist
))
1237 mutex_lock(&shmem_swaplist_mutex
);
1240 * The extra refcount on the inode is necessary to safely dereference
1241 * p->next after re-acquiring the lock. New shmem inodes with swap
1242 * get added to the end of the list and we will scan them all.
1244 list_for_each_entry_safe(info
, next
, &shmem_swaplist
, swaplist
) {
1245 if (!info
->swapped
) {
1246 list_del_init(&info
->swaplist
);
1250 inode
= igrab(&info
->vfs_inode
);
1254 mutex_unlock(&shmem_swaplist_mutex
);
1259 error
= shmem_unuse_inode(inode
, type
, frontswap
,
1263 mutex_lock(&shmem_swaplist_mutex
);
1264 next
= list_next_entry(info
, swaplist
);
1266 list_del_init(&info
->swaplist
);
1270 mutex_unlock(&shmem_swaplist_mutex
);
1279 * Move the page from the page cache to the swap cache.
1281 static int shmem_writepage(struct page
*page
, struct writeback_control
*wbc
)
1283 struct shmem_inode_info
*info
;
1284 struct address_space
*mapping
;
1285 struct inode
*inode
;
1289 VM_BUG_ON_PAGE(PageCompound(page
), page
);
1290 BUG_ON(!PageLocked(page
));
1291 mapping
= page
->mapping
;
1292 index
= page
->index
;
1293 inode
= mapping
->host
;
1294 info
= SHMEM_I(inode
);
1295 if (info
->flags
& VM_LOCKED
)
1297 if (!total_swap_pages
)
1301 * Our capabilities prevent regular writeback or sync from ever calling
1302 * shmem_writepage; but a stacking filesystem might use ->writepage of
1303 * its underlying filesystem, in which case tmpfs should write out to
1304 * swap only in response to memory pressure, and not for the writeback
1307 if (!wbc
->for_reclaim
) {
1308 WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
1313 * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
1314 * value into swapfile.c, the only way we can correctly account for a
1315 * fallocated page arriving here is now to initialize it and write it.
1317 * That's okay for a page already fallocated earlier, but if we have
1318 * not yet completed the fallocation, then (a) we want to keep track
1319 * of this page in case we have to undo it, and (b) it may not be a
1320 * good idea to continue anyway, once we're pushing into swap. So
1321 * reactivate the page, and let shmem_fallocate() quit when too many.
1323 if (!PageUptodate(page
)) {
1324 if (inode
->i_private
) {
1325 struct shmem_falloc
*shmem_falloc
;
1326 spin_lock(&inode
->i_lock
);
1327 shmem_falloc
= inode
->i_private
;
1329 !shmem_falloc
->waitq
&&
1330 index
>= shmem_falloc
->start
&&
1331 index
< shmem_falloc
->next
)
1332 shmem_falloc
->nr_unswapped
++;
1334 shmem_falloc
= NULL
;
1335 spin_unlock(&inode
->i_lock
);
1339 clear_highpage(page
);
1340 flush_dcache_page(page
);
1341 SetPageUptodate(page
);
1344 swap
= get_swap_page(page
);
1349 * Add inode to shmem_unuse()'s list of swapped-out inodes,
1350 * if it's not already there. Do it now before the page is
1351 * moved to swap cache, when its pagelock no longer protects
1352 * the inode from eviction. But don't unlock the mutex until
1353 * we've incremented swapped, because shmem_unuse_inode() will
1354 * prune a !swapped inode from the swaplist under this mutex.
1356 mutex_lock(&shmem_swaplist_mutex
);
1357 if (list_empty(&info
->swaplist
))
1358 list_add(&info
->swaplist
, &shmem_swaplist
);
1360 if (add_to_swap_cache(page
, swap
, GFP_ATOMIC
) == 0) {
1361 spin_lock_irq(&info
->lock
);
1362 shmem_recalc_inode(inode
);
1364 spin_unlock_irq(&info
->lock
);
1366 swap_shmem_alloc(swap
);
1367 shmem_delete_from_page_cache(page
, swp_to_radix_entry(swap
));
1369 mutex_unlock(&shmem_swaplist_mutex
);
1370 BUG_ON(page_mapped(page
));
1371 swap_writepage(page
, wbc
);
1375 mutex_unlock(&shmem_swaplist_mutex
);
1376 put_swap_page(page
, swap
);
1378 set_page_dirty(page
);
1379 if (wbc
->for_reclaim
)
1380 return AOP_WRITEPAGE_ACTIVATE
; /* Return with page locked */
1385 #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
1386 static void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1390 if (!mpol
|| mpol
->mode
== MPOL_DEFAULT
)
1391 return; /* show nothing */
1393 mpol_to_str(buffer
, sizeof(buffer
), mpol
);
1395 seq_printf(seq
, ",mpol=%s", buffer
);
1398 static struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1400 struct mempolicy
*mpol
= NULL
;
1402 spin_lock(&sbinfo
->stat_lock
); /* prevent replace/use races */
1403 mpol
= sbinfo
->mpol
;
1405 spin_unlock(&sbinfo
->stat_lock
);
1409 #else /* !CONFIG_NUMA || !CONFIG_TMPFS */
1410 static inline void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1413 static inline struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1417 #endif /* CONFIG_NUMA && CONFIG_TMPFS */
1419 #define vm_policy vm_private_data
1422 static void shmem_pseudo_vma_init(struct vm_area_struct
*vma
,
1423 struct shmem_inode_info
*info
, pgoff_t index
)
1425 /* Create a pseudo vma that just contains the policy */
1426 vma_init(vma
, NULL
);
1427 /* Bias interleave by inode number to distribute better across nodes */
1428 vma
->vm_pgoff
= index
+ info
->vfs_inode
.i_ino
;
1429 vma
->vm_policy
= mpol_shared_policy_lookup(&info
->policy
, index
);
1432 static void shmem_pseudo_vma_destroy(struct vm_area_struct
*vma
)
1434 /* Drop reference taken by mpol_shared_policy_lookup() */
1435 mpol_cond_put(vma
->vm_policy
);
1438 static struct page
*shmem_swapin(swp_entry_t swap
, gfp_t gfp
,
1439 struct shmem_inode_info
*info
, pgoff_t index
)
1441 struct vm_area_struct pvma
;
1443 struct vm_fault vmf
;
1445 shmem_pseudo_vma_init(&pvma
, info
, index
);
1448 page
= swap_cluster_readahead(swap
, gfp
, &vmf
);
1449 shmem_pseudo_vma_destroy(&pvma
);
1454 static struct page
*shmem_alloc_hugepage(gfp_t gfp
,
1455 struct shmem_inode_info
*info
, pgoff_t index
)
1457 struct vm_area_struct pvma
;
1458 struct address_space
*mapping
= info
->vfs_inode
.i_mapping
;
1462 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
))
1465 hindex
= round_down(index
, HPAGE_PMD_NR
);
1466 if (xa_find(&mapping
->i_pages
, &hindex
, hindex
+ HPAGE_PMD_NR
- 1,
1470 shmem_pseudo_vma_init(&pvma
, info
, hindex
);
1471 page
= alloc_pages_vma(gfp
| __GFP_COMP
| __GFP_NORETRY
| __GFP_NOWARN
,
1472 HPAGE_PMD_ORDER
, &pvma
, 0, numa_node_id(), true);
1473 shmem_pseudo_vma_destroy(&pvma
);
1475 prep_transhuge_page(page
);
1479 static struct page
*shmem_alloc_page(gfp_t gfp
,
1480 struct shmem_inode_info
*info
, pgoff_t index
)
1482 struct vm_area_struct pvma
;
1485 shmem_pseudo_vma_init(&pvma
, info
, index
);
1486 page
= alloc_page_vma(gfp
, &pvma
, 0);
1487 shmem_pseudo_vma_destroy(&pvma
);
1492 static struct page
*shmem_alloc_and_acct_page(gfp_t gfp
,
1493 struct inode
*inode
,
1494 pgoff_t index
, bool huge
)
1496 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1501 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
))
1503 nr
= huge
? HPAGE_PMD_NR
: 1;
1505 if (!shmem_inode_acct_block(inode
, nr
))
1509 page
= shmem_alloc_hugepage(gfp
, info
, index
);
1511 page
= shmem_alloc_page(gfp
, info
, index
);
1513 __SetPageLocked(page
);
1514 __SetPageSwapBacked(page
);
1519 shmem_inode_unacct_blocks(inode
, nr
);
1521 return ERR_PTR(err
);
1525 * When a page is moved from swapcache to shmem filecache (either by the
1526 * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
1527 * shmem_unuse_inode()), it may have been read in earlier from swap, in
1528 * ignorance of the mapping it belongs to. If that mapping has special
1529 * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
1530 * we may need to copy to a suitable page before moving to filecache.
1532 * In a future release, this may well be extended to respect cpuset and
1533 * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
1534 * but for now it is a simple matter of zone.
1536 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
)
1538 return page_zonenum(page
) > gfp_zone(gfp
);
1541 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
1542 struct shmem_inode_info
*info
, pgoff_t index
)
1544 struct page
*oldpage
, *newpage
;
1545 struct address_space
*swap_mapping
;
1551 entry
.val
= page_private(oldpage
);
1552 swap_index
= swp_offset(entry
);
1553 swap_mapping
= page_mapping(oldpage
);
1556 * We have arrived here because our zones are constrained, so don't
1557 * limit chance of success by further cpuset and node constraints.
1559 gfp
&= ~GFP_CONSTRAINT_MASK
;
1560 newpage
= shmem_alloc_page(gfp
, info
, index
);
1565 copy_highpage(newpage
, oldpage
);
1566 flush_dcache_page(newpage
);
1568 __SetPageLocked(newpage
);
1569 __SetPageSwapBacked(newpage
);
1570 SetPageUptodate(newpage
);
1571 set_page_private(newpage
, entry
.val
);
1572 SetPageSwapCache(newpage
);
1575 * Our caller will very soon move newpage out of swapcache, but it's
1576 * a nice clean interface for us to replace oldpage by newpage there.
1578 xa_lock_irq(&swap_mapping
->i_pages
);
1579 error
= shmem_replace_entry(swap_mapping
, swap_index
, oldpage
, newpage
);
1581 __inc_node_page_state(newpage
, NR_FILE_PAGES
);
1582 __dec_node_page_state(oldpage
, NR_FILE_PAGES
);
1584 xa_unlock_irq(&swap_mapping
->i_pages
);
1586 if (unlikely(error
)) {
1588 * Is this possible? I think not, now that our callers check
1589 * both PageSwapCache and page_private after getting page lock;
1590 * but be defensive. Reverse old to newpage for clear and free.
1594 mem_cgroup_migrate(oldpage
, newpage
);
1595 lru_cache_add_anon(newpage
);
1599 ClearPageSwapCache(oldpage
);
1600 set_page_private(oldpage
, 0);
1602 unlock_page(oldpage
);
1609 * Swap in the page pointed to by *pagep.
1610 * Caller has to make sure that *pagep contains a valid swapped page.
1611 * Returns 0 and the page in pagep if success. On failure, returns the
1612 * the error code and NULL in *pagep.
1614 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
1615 struct page
**pagep
, enum sgp_type sgp
,
1616 gfp_t gfp
, struct vm_area_struct
*vma
,
1617 vm_fault_t
*fault_type
)
1619 struct address_space
*mapping
= inode
->i_mapping
;
1620 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1621 struct mm_struct
*charge_mm
= vma
? vma
->vm_mm
: current
->mm
;
1622 struct mem_cgroup
*memcg
;
1627 VM_BUG_ON(!*pagep
|| !xa_is_value(*pagep
));
1628 swap
= radix_to_swp_entry(*pagep
);
1631 /* Look it up and read it in.. */
1632 page
= lookup_swap_cache(swap
, NULL
, 0);
1634 /* Or update major stats only when swapin succeeds?? */
1636 *fault_type
|= VM_FAULT_MAJOR
;
1637 count_vm_event(PGMAJFAULT
);
1638 count_memcg_event_mm(charge_mm
, PGMAJFAULT
);
1640 /* Here we actually start the io */
1641 page
= shmem_swapin(swap
, gfp
, info
, index
);
1648 /* We have to do this with page locked to prevent races */
1650 if (!PageSwapCache(page
) || page_private(page
) != swap
.val
||
1651 !shmem_confirm_swap(mapping
, index
, swap
)) {
1655 if (!PageUptodate(page
)) {
1659 wait_on_page_writeback(page
);
1661 if (shmem_should_replace_page(page
, gfp
)) {
1662 error
= shmem_replace_page(&page
, gfp
, info
, index
);
1667 error
= mem_cgroup_try_charge_delay(page
, charge_mm
, gfp
, &memcg
,
1670 error
= shmem_add_to_page_cache(page
, mapping
, index
,
1671 swp_to_radix_entry(swap
), gfp
);
1673 * We already confirmed swap under page lock, and make
1674 * no memory allocation here, so usually no possibility
1675 * of error; but free_swap_and_cache() only trylocks a
1676 * page, so it is just possible that the entry has been
1677 * truncated or holepunched since swap was confirmed.
1678 * shmem_undo_range() will have done some of the
1679 * unaccounting, now delete_from_swap_cache() will do
1683 mem_cgroup_cancel_charge(page
, memcg
, false);
1684 delete_from_swap_cache(page
);
1690 mem_cgroup_commit_charge(page
, memcg
, true, false);
1692 spin_lock_irq(&info
->lock
);
1694 shmem_recalc_inode(inode
);
1695 spin_unlock_irq(&info
->lock
);
1697 if (sgp
== SGP_WRITE
)
1698 mark_page_accessed(page
);
1700 delete_from_swap_cache(page
);
1701 set_page_dirty(page
);
1707 if (!shmem_confirm_swap(mapping
, index
, swap
))
1719 * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
1721 * If we allocate a new one we do not mark it dirty. That's up to the
1722 * vm. If we swap it in we mark it dirty since we also free the swap
1723 * entry since a page cannot live in both the swap and page cache.
1725 * fault_mm and fault_type are only supplied by shmem_fault:
1726 * otherwise they are NULL.
1728 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
1729 struct page
**pagep
, enum sgp_type sgp
, gfp_t gfp
,
1730 struct vm_area_struct
*vma
, struct vm_fault
*vmf
,
1731 vm_fault_t
*fault_type
)
1733 struct address_space
*mapping
= inode
->i_mapping
;
1734 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1735 struct shmem_sb_info
*sbinfo
;
1736 struct mm_struct
*charge_mm
;
1737 struct mem_cgroup
*memcg
;
1739 enum sgp_type sgp_huge
= sgp
;
1740 pgoff_t hindex
= index
;
1745 if (index
> (MAX_LFS_FILESIZE
>> PAGE_SHIFT
))
1747 if (sgp
== SGP_NOHUGE
|| sgp
== SGP_HUGE
)
1750 if (sgp
<= SGP_CACHE
&&
1751 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1755 sbinfo
= SHMEM_SB(inode
->i_sb
);
1756 charge_mm
= vma
? vma
->vm_mm
: current
->mm
;
1758 page
= find_lock_entry(mapping
, index
);
1759 if (xa_is_value(page
)) {
1760 error
= shmem_swapin_page(inode
, index
, &page
,
1761 sgp
, gfp
, vma
, fault_type
);
1762 if (error
== -EEXIST
)
1769 if (page
&& sgp
== SGP_WRITE
)
1770 mark_page_accessed(page
);
1772 /* fallocated page? */
1773 if (page
&& !PageUptodate(page
)) {
1774 if (sgp
!= SGP_READ
)
1780 if (page
|| sgp
== SGP_READ
) {
1786 * Fast cache lookup did not find it:
1787 * bring it back from swap or allocate.
1790 if (vma
&& userfaultfd_missing(vma
)) {
1791 *fault_type
= handle_userfault(vmf
, VM_UFFD_MISSING
);
1795 /* shmem_symlink() */
1796 if (mapping
->a_ops
!= &shmem_aops
)
1798 if (shmem_huge
== SHMEM_HUGE_DENY
|| sgp_huge
== SGP_NOHUGE
)
1800 if (shmem_huge
== SHMEM_HUGE_FORCE
)
1802 switch (sbinfo
->huge
) {
1805 case SHMEM_HUGE_NEVER
:
1807 case SHMEM_HUGE_WITHIN_SIZE
:
1808 off
= round_up(index
, HPAGE_PMD_NR
);
1809 i_size
= round_up(i_size_read(inode
), PAGE_SIZE
);
1810 if (i_size
>= HPAGE_PMD_SIZE
&&
1811 i_size
>> PAGE_SHIFT
>= off
)
1814 case SHMEM_HUGE_ADVISE
:
1815 if (sgp_huge
== SGP_HUGE
)
1817 /* TODO: implement fadvise() hints */
1822 page
= shmem_alloc_and_acct_page(gfp
, inode
, index
, true);
1825 page
= shmem_alloc_and_acct_page(gfp
, inode
,
1831 error
= PTR_ERR(page
);
1833 if (error
!= -ENOSPC
)
1836 * Try to reclaim some space by splitting a huge page
1837 * beyond i_size on the filesystem.
1842 ret
= shmem_unused_huge_shrink(sbinfo
, NULL
, 1);
1843 if (ret
== SHRINK_STOP
)
1851 if (PageTransHuge(page
))
1852 hindex
= round_down(index
, HPAGE_PMD_NR
);
1856 if (sgp
== SGP_WRITE
)
1857 __SetPageReferenced(page
);
1859 error
= mem_cgroup_try_charge_delay(page
, charge_mm
, gfp
, &memcg
,
1860 PageTransHuge(page
));
1863 error
= shmem_add_to_page_cache(page
, mapping
, hindex
,
1864 NULL
, gfp
& GFP_RECLAIM_MASK
);
1866 mem_cgroup_cancel_charge(page
, memcg
,
1867 PageTransHuge(page
));
1870 mem_cgroup_commit_charge(page
, memcg
, false,
1871 PageTransHuge(page
));
1872 lru_cache_add_anon(page
);
1874 spin_lock_irq(&info
->lock
);
1875 info
->alloced
+= 1 << compound_order(page
);
1876 inode
->i_blocks
+= BLOCKS_PER_PAGE
<< compound_order(page
);
1877 shmem_recalc_inode(inode
);
1878 spin_unlock_irq(&info
->lock
);
1881 if (PageTransHuge(page
) &&
1882 DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
) <
1883 hindex
+ HPAGE_PMD_NR
- 1) {
1885 * Part of the huge page is beyond i_size: subject
1886 * to shrink under memory pressure.
1888 spin_lock(&sbinfo
->shrinklist_lock
);
1890 * _careful to defend against unlocked access to
1891 * ->shrink_list in shmem_unused_huge_shrink()
1893 if (list_empty_careful(&info
->shrinklist
)) {
1894 list_add_tail(&info
->shrinklist
,
1895 &sbinfo
->shrinklist
);
1896 sbinfo
->shrinklist_len
++;
1898 spin_unlock(&sbinfo
->shrinklist_lock
);
1902 * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
1904 if (sgp
== SGP_FALLOC
)
1908 * Let SGP_WRITE caller clear ends if write does not fill page;
1909 * but SGP_FALLOC on a page fallocated earlier must initialize
1910 * it now, lest undo on failure cancel our earlier guarantee.
1912 if (sgp
!= SGP_WRITE
&& !PageUptodate(page
)) {
1913 struct page
*head
= compound_head(page
);
1916 for (i
= 0; i
< (1 << compound_order(head
)); i
++) {
1917 clear_highpage(head
+ i
);
1918 flush_dcache_page(head
+ i
);
1920 SetPageUptodate(head
);
1923 /* Perhaps the file has been truncated since we checked */
1924 if (sgp
<= SGP_CACHE
&&
1925 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1927 ClearPageDirty(page
);
1928 delete_from_page_cache(page
);
1929 spin_lock_irq(&info
->lock
);
1930 shmem_recalc_inode(inode
);
1931 spin_unlock_irq(&info
->lock
);
1936 *pagep
= page
+ index
- hindex
;
1943 shmem_inode_unacct_blocks(inode
, 1 << compound_order(page
));
1945 if (PageTransHuge(page
)) {
1955 if (error
== -ENOSPC
&& !once
++) {
1956 spin_lock_irq(&info
->lock
);
1957 shmem_recalc_inode(inode
);
1958 spin_unlock_irq(&info
->lock
);
1961 if (error
== -EEXIST
)
1967 * This is like autoremove_wake_function, but it removes the wait queue
1968 * entry unconditionally - even if something else had already woken the
1971 static int synchronous_wake_function(wait_queue_entry_t
*wait
, unsigned mode
, int sync
, void *key
)
1973 int ret
= default_wake_function(wait
, mode
, sync
, key
);
1974 list_del_init(&wait
->entry
);
1978 static vm_fault_t
shmem_fault(struct vm_fault
*vmf
)
1980 struct vm_area_struct
*vma
= vmf
->vma
;
1981 struct inode
*inode
= file_inode(vma
->vm_file
);
1982 gfp_t gfp
= mapping_gfp_mask(inode
->i_mapping
);
1985 vm_fault_t ret
= VM_FAULT_LOCKED
;
1988 * Trinity finds that probing a hole which tmpfs is punching can
1989 * prevent the hole-punch from ever completing: which in turn
1990 * locks writers out with its hold on i_mutex. So refrain from
1991 * faulting pages into the hole while it's being punched. Although
1992 * shmem_undo_range() does remove the additions, it may be unable to
1993 * keep up, as each new page needs its own unmap_mapping_range() call,
1994 * and the i_mmap tree grows ever slower to scan if new vmas are added.
1996 * It does not matter if we sometimes reach this check just before the
1997 * hole-punch begins, so that one fault then races with the punch:
1998 * we just need to make racing faults a rare case.
2000 * The implementation below would be much simpler if we just used a
2001 * standard mutex or completion: but we cannot take i_mutex in fault,
2002 * and bloating every shmem inode for this unlikely case would be sad.
2004 if (unlikely(inode
->i_private
)) {
2005 struct shmem_falloc
*shmem_falloc
;
2007 spin_lock(&inode
->i_lock
);
2008 shmem_falloc
= inode
->i_private
;
2010 shmem_falloc
->waitq
&&
2011 vmf
->pgoff
>= shmem_falloc
->start
&&
2012 vmf
->pgoff
< shmem_falloc
->next
) {
2013 wait_queue_head_t
*shmem_falloc_waitq
;
2014 DEFINE_WAIT_FUNC(shmem_fault_wait
, synchronous_wake_function
);
2016 ret
= VM_FAULT_NOPAGE
;
2017 if ((vmf
->flags
& FAULT_FLAG_ALLOW_RETRY
) &&
2018 !(vmf
->flags
& FAULT_FLAG_RETRY_NOWAIT
)) {
2019 /* It's polite to up mmap_sem if we can */
2020 up_read(&vma
->vm_mm
->mmap_sem
);
2021 ret
= VM_FAULT_RETRY
;
2024 shmem_falloc_waitq
= shmem_falloc
->waitq
;
2025 prepare_to_wait(shmem_falloc_waitq
, &shmem_fault_wait
,
2026 TASK_UNINTERRUPTIBLE
);
2027 spin_unlock(&inode
->i_lock
);
2031 * shmem_falloc_waitq points into the shmem_fallocate()
2032 * stack of the hole-punching task: shmem_falloc_waitq
2033 * is usually invalid by the time we reach here, but
2034 * finish_wait() does not dereference it in that case;
2035 * though i_lock needed lest racing with wake_up_all().
2037 spin_lock(&inode
->i_lock
);
2038 finish_wait(shmem_falloc_waitq
, &shmem_fault_wait
);
2039 spin_unlock(&inode
->i_lock
);
2042 spin_unlock(&inode
->i_lock
);
2047 if ((vma
->vm_flags
& VM_NOHUGEPAGE
) ||
2048 test_bit(MMF_DISABLE_THP
, &vma
->vm_mm
->flags
))
2050 else if (vma
->vm_flags
& VM_HUGEPAGE
)
2053 err
= shmem_getpage_gfp(inode
, vmf
->pgoff
, &vmf
->page
, sgp
,
2054 gfp
, vma
, vmf
, &ret
);
2056 return vmf_error(err
);
2060 unsigned long shmem_get_unmapped_area(struct file
*file
,
2061 unsigned long uaddr
, unsigned long len
,
2062 unsigned long pgoff
, unsigned long flags
)
2064 unsigned long (*get_area
)(struct file
*,
2065 unsigned long, unsigned long, unsigned long, unsigned long);
2067 unsigned long offset
;
2068 unsigned long inflated_len
;
2069 unsigned long inflated_addr
;
2070 unsigned long inflated_offset
;
2072 if (len
> TASK_SIZE
)
2075 get_area
= current
->mm
->get_unmapped_area
;
2076 addr
= get_area(file
, uaddr
, len
, pgoff
, flags
);
2078 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
))
2080 if (IS_ERR_VALUE(addr
))
2082 if (addr
& ~PAGE_MASK
)
2084 if (addr
> TASK_SIZE
- len
)
2087 if (shmem_huge
== SHMEM_HUGE_DENY
)
2089 if (len
< HPAGE_PMD_SIZE
)
2091 if (flags
& MAP_FIXED
)
2094 * Our priority is to support MAP_SHARED mapped hugely;
2095 * and support MAP_PRIVATE mapped hugely too, until it is COWed.
2096 * But if caller specified an address hint, respect that as before.
2101 if (shmem_huge
!= SHMEM_HUGE_FORCE
) {
2102 struct super_block
*sb
;
2105 VM_BUG_ON(file
->f_op
!= &shmem_file_operations
);
2106 sb
= file_inode(file
)->i_sb
;
2109 * Called directly from mm/mmap.c, or drivers/char/mem.c
2110 * for "/dev/zero", to create a shared anonymous object.
2112 if (IS_ERR(shm_mnt
))
2114 sb
= shm_mnt
->mnt_sb
;
2116 if (SHMEM_SB(sb
)->huge
== SHMEM_HUGE_NEVER
)
2120 offset
= (pgoff
<< PAGE_SHIFT
) & (HPAGE_PMD_SIZE
-1);
2121 if (offset
&& offset
+ len
< 2 * HPAGE_PMD_SIZE
)
2123 if ((addr
& (HPAGE_PMD_SIZE
-1)) == offset
)
2126 inflated_len
= len
+ HPAGE_PMD_SIZE
- PAGE_SIZE
;
2127 if (inflated_len
> TASK_SIZE
)
2129 if (inflated_len
< len
)
2132 inflated_addr
= get_area(NULL
, 0, inflated_len
, 0, flags
);
2133 if (IS_ERR_VALUE(inflated_addr
))
2135 if (inflated_addr
& ~PAGE_MASK
)
2138 inflated_offset
= inflated_addr
& (HPAGE_PMD_SIZE
-1);
2139 inflated_addr
+= offset
- inflated_offset
;
2140 if (inflated_offset
> offset
)
2141 inflated_addr
+= HPAGE_PMD_SIZE
;
2143 if (inflated_addr
> TASK_SIZE
- len
)
2145 return inflated_addr
;
2149 static int shmem_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
2151 struct inode
*inode
= file_inode(vma
->vm_file
);
2152 return mpol_set_shared_policy(&SHMEM_I(inode
)->policy
, vma
, mpol
);
2155 static struct mempolicy
*shmem_get_policy(struct vm_area_struct
*vma
,
2158 struct inode
*inode
= file_inode(vma
->vm_file
);
2161 index
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2162 return mpol_shared_policy_lookup(&SHMEM_I(inode
)->policy
, index
);
2166 int shmem_lock(struct file
*file
, int lock
, struct user_struct
*user
)
2168 struct inode
*inode
= file_inode(file
);
2169 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2170 int retval
= -ENOMEM
;
2172 spin_lock_irq(&info
->lock
);
2173 if (lock
&& !(info
->flags
& VM_LOCKED
)) {
2174 if (!user_shm_lock(inode
->i_size
, user
))
2176 info
->flags
|= VM_LOCKED
;
2177 mapping_set_unevictable(file
->f_mapping
);
2179 if (!lock
&& (info
->flags
& VM_LOCKED
) && user
) {
2180 user_shm_unlock(inode
->i_size
, user
);
2181 info
->flags
&= ~VM_LOCKED
;
2182 mapping_clear_unevictable(file
->f_mapping
);
2187 spin_unlock_irq(&info
->lock
);
2191 static int shmem_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2193 struct shmem_inode_info
*info
= SHMEM_I(file_inode(file
));
2195 if (info
->seals
& F_SEAL_FUTURE_WRITE
) {
2197 * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
2198 * "future write" seal active.
2200 if ((vma
->vm_flags
& VM_SHARED
) && (vma
->vm_flags
& VM_WRITE
))
2204 * Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED
2205 * read-only mapping, take care to not allow mprotect to revert
2208 vma
->vm_flags
&= ~(VM_MAYWRITE
);
2211 file_accessed(file
);
2212 vma
->vm_ops
= &shmem_vm_ops
;
2213 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
) &&
2214 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
2215 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
2216 khugepaged_enter(vma
, vma
->vm_flags
);
2221 static struct inode
*shmem_get_inode(struct super_block
*sb
, const struct inode
*dir
,
2222 umode_t mode
, dev_t dev
, unsigned long flags
)
2224 struct inode
*inode
;
2225 struct shmem_inode_info
*info
;
2226 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
2228 if (shmem_reserve_inode(sb
))
2231 inode
= new_inode(sb
);
2233 inode
->i_ino
= get_next_ino();
2234 inode_init_owner(inode
, dir
, mode
);
2235 inode
->i_blocks
= 0;
2236 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= current_time(inode
);
2237 inode
->i_generation
= prandom_u32();
2238 info
= SHMEM_I(inode
);
2239 memset(info
, 0, (char *)inode
- (char *)info
);
2240 spin_lock_init(&info
->lock
);
2241 info
->seals
= F_SEAL_SEAL
;
2242 info
->flags
= flags
& VM_NORESERVE
;
2243 INIT_LIST_HEAD(&info
->shrinklist
);
2244 INIT_LIST_HEAD(&info
->swaplist
);
2245 simple_xattrs_init(&info
->xattrs
);
2246 cache_no_acl(inode
);
2248 switch (mode
& S_IFMT
) {
2250 inode
->i_op
= &shmem_special_inode_operations
;
2251 init_special_inode(inode
, mode
, dev
);
2254 inode
->i_mapping
->a_ops
= &shmem_aops
;
2255 inode
->i_op
= &shmem_inode_operations
;
2256 inode
->i_fop
= &shmem_file_operations
;
2257 mpol_shared_policy_init(&info
->policy
,
2258 shmem_get_sbmpol(sbinfo
));
2262 /* Some things misbehave if size == 0 on a directory */
2263 inode
->i_size
= 2 * BOGO_DIRENT_SIZE
;
2264 inode
->i_op
= &shmem_dir_inode_operations
;
2265 inode
->i_fop
= &simple_dir_operations
;
2269 * Must not load anything in the rbtree,
2270 * mpol_free_shared_policy will not be called.
2272 mpol_shared_policy_init(&info
->policy
, NULL
);
2276 lockdep_annotate_inode_mutex_key(inode
);
2278 shmem_free_inode(sb
);
2282 bool shmem_mapping(struct address_space
*mapping
)
2284 return mapping
->a_ops
== &shmem_aops
;
2287 static int shmem_mfill_atomic_pte(struct mm_struct
*dst_mm
,
2289 struct vm_area_struct
*dst_vma
,
2290 unsigned long dst_addr
,
2291 unsigned long src_addr
,
2293 struct page
**pagep
)
2295 struct inode
*inode
= file_inode(dst_vma
->vm_file
);
2296 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2297 struct address_space
*mapping
= inode
->i_mapping
;
2298 gfp_t gfp
= mapping_gfp_mask(mapping
);
2299 pgoff_t pgoff
= linear_page_index(dst_vma
, dst_addr
);
2300 struct mem_cgroup
*memcg
;
2304 pte_t _dst_pte
, *dst_pte
;
2306 pgoff_t offset
, max_off
;
2309 if (!shmem_inode_acct_block(inode
, 1))
2313 page
= shmem_alloc_page(gfp
, info
, pgoff
);
2315 goto out_unacct_blocks
;
2317 if (!zeropage
) { /* mcopy_atomic */
2318 page_kaddr
= kmap_atomic(page
);
2319 ret
= copy_from_user(page_kaddr
,
2320 (const void __user
*)src_addr
,
2322 kunmap_atomic(page_kaddr
);
2324 /* fallback to copy_from_user outside mmap_sem */
2325 if (unlikely(ret
)) {
2327 shmem_inode_unacct_blocks(inode
, 1);
2328 /* don't free the page */
2331 } else { /* mfill_zeropage_atomic */
2332 clear_highpage(page
);
2339 VM_BUG_ON(PageLocked(page
) || PageSwapBacked(page
));
2340 __SetPageLocked(page
);
2341 __SetPageSwapBacked(page
);
2342 __SetPageUptodate(page
);
2345 offset
= linear_page_index(dst_vma
, dst_addr
);
2346 max_off
= DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
);
2347 if (unlikely(offset
>= max_off
))
2350 ret
= mem_cgroup_try_charge_delay(page
, dst_mm
, gfp
, &memcg
, false);
2354 ret
= shmem_add_to_page_cache(page
, mapping
, pgoff
, NULL
,
2355 gfp
& GFP_RECLAIM_MASK
);
2357 goto out_release_uncharge
;
2359 mem_cgroup_commit_charge(page
, memcg
, false, false);
2361 _dst_pte
= mk_pte(page
, dst_vma
->vm_page_prot
);
2362 if (dst_vma
->vm_flags
& VM_WRITE
)
2363 _dst_pte
= pte_mkwrite(pte_mkdirty(_dst_pte
));
2366 * We don't set the pte dirty if the vma has no
2367 * VM_WRITE permission, so mark the page dirty or it
2368 * could be freed from under us. We could do it
2369 * unconditionally before unlock_page(), but doing it
2370 * only if VM_WRITE is not set is faster.
2372 set_page_dirty(page
);
2375 dst_pte
= pte_offset_map_lock(dst_mm
, dst_pmd
, dst_addr
, &ptl
);
2378 max_off
= DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
);
2379 if (unlikely(offset
>= max_off
))
2380 goto out_release_uncharge_unlock
;
2383 if (!pte_none(*dst_pte
))
2384 goto out_release_uncharge_unlock
;
2386 lru_cache_add_anon(page
);
2388 spin_lock(&info
->lock
);
2390 inode
->i_blocks
+= BLOCKS_PER_PAGE
;
2391 shmem_recalc_inode(inode
);
2392 spin_unlock(&info
->lock
);
2394 inc_mm_counter(dst_mm
, mm_counter_file(page
));
2395 page_add_file_rmap(page
, false);
2396 set_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
2398 /* No need to invalidate - it was non-present before */
2399 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
2400 pte_unmap_unlock(dst_pte
, ptl
);
2405 out_release_uncharge_unlock
:
2406 pte_unmap_unlock(dst_pte
, ptl
);
2407 ClearPageDirty(page
);
2408 delete_from_page_cache(page
);
2409 out_release_uncharge
:
2410 mem_cgroup_cancel_charge(page
, memcg
, false);
2415 shmem_inode_unacct_blocks(inode
, 1);
2419 int shmem_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
2421 struct vm_area_struct
*dst_vma
,
2422 unsigned long dst_addr
,
2423 unsigned long src_addr
,
2424 struct page
**pagep
)
2426 return shmem_mfill_atomic_pte(dst_mm
, dst_pmd
, dst_vma
,
2427 dst_addr
, src_addr
, false, pagep
);
2430 int shmem_mfill_zeropage_pte(struct mm_struct
*dst_mm
,
2432 struct vm_area_struct
*dst_vma
,
2433 unsigned long dst_addr
)
2435 struct page
*page
= NULL
;
2437 return shmem_mfill_atomic_pte(dst_mm
, dst_pmd
, dst_vma
,
2438 dst_addr
, 0, true, &page
);
2442 static const struct inode_operations shmem_symlink_inode_operations
;
2443 static const struct inode_operations shmem_short_symlink_operations
;
2445 #ifdef CONFIG_TMPFS_XATTR
2446 static int shmem_initxattrs(struct inode
*, const struct xattr
*, void *);
2448 #define shmem_initxattrs NULL
2452 shmem_write_begin(struct file
*file
, struct address_space
*mapping
,
2453 loff_t pos
, unsigned len
, unsigned flags
,
2454 struct page
**pagep
, void **fsdata
)
2456 struct inode
*inode
= mapping
->host
;
2457 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2458 pgoff_t index
= pos
>> PAGE_SHIFT
;
2460 /* i_mutex is held by caller */
2461 if (unlikely(info
->seals
& (F_SEAL_GROW
|
2462 F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))) {
2463 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))
2465 if ((info
->seals
& F_SEAL_GROW
) && pos
+ len
> inode
->i_size
)
2469 return shmem_getpage(inode
, index
, pagep
, SGP_WRITE
);
2473 shmem_write_end(struct file
*file
, struct address_space
*mapping
,
2474 loff_t pos
, unsigned len
, unsigned copied
,
2475 struct page
*page
, void *fsdata
)
2477 struct inode
*inode
= mapping
->host
;
2479 if (pos
+ copied
> inode
->i_size
)
2480 i_size_write(inode
, pos
+ copied
);
2482 if (!PageUptodate(page
)) {
2483 struct page
*head
= compound_head(page
);
2484 if (PageTransCompound(page
)) {
2487 for (i
= 0; i
< HPAGE_PMD_NR
; i
++) {
2488 if (head
+ i
== page
)
2490 clear_highpage(head
+ i
);
2491 flush_dcache_page(head
+ i
);
2494 if (copied
< PAGE_SIZE
) {
2495 unsigned from
= pos
& (PAGE_SIZE
- 1);
2496 zero_user_segments(page
, 0, from
,
2497 from
+ copied
, PAGE_SIZE
);
2499 SetPageUptodate(head
);
2501 set_page_dirty(page
);
2508 static ssize_t
shmem_file_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
2510 struct file
*file
= iocb
->ki_filp
;
2511 struct inode
*inode
= file_inode(file
);
2512 struct address_space
*mapping
= inode
->i_mapping
;
2514 unsigned long offset
;
2515 enum sgp_type sgp
= SGP_READ
;
2518 loff_t
*ppos
= &iocb
->ki_pos
;
2521 * Might this read be for a stacking filesystem? Then when reading
2522 * holes of a sparse file, we actually need to allocate those pages,
2523 * and even mark them dirty, so it cannot exceed the max_blocks limit.
2525 if (!iter_is_iovec(to
))
2528 index
= *ppos
>> PAGE_SHIFT
;
2529 offset
= *ppos
& ~PAGE_MASK
;
2532 struct page
*page
= NULL
;
2534 unsigned long nr
, ret
;
2535 loff_t i_size
= i_size_read(inode
);
2537 end_index
= i_size
>> PAGE_SHIFT
;
2538 if (index
> end_index
)
2540 if (index
== end_index
) {
2541 nr
= i_size
& ~PAGE_MASK
;
2546 error
= shmem_getpage(inode
, index
, &page
, sgp
);
2548 if (error
== -EINVAL
)
2553 if (sgp
== SGP_CACHE
)
2554 set_page_dirty(page
);
2559 * We must evaluate after, since reads (unlike writes)
2560 * are called without i_mutex protection against truncate
2563 i_size
= i_size_read(inode
);
2564 end_index
= i_size
>> PAGE_SHIFT
;
2565 if (index
== end_index
) {
2566 nr
= i_size
& ~PAGE_MASK
;
2577 * If users can be writing to this page using arbitrary
2578 * virtual addresses, take care about potential aliasing
2579 * before reading the page on the kernel side.
2581 if (mapping_writably_mapped(mapping
))
2582 flush_dcache_page(page
);
2584 * Mark the page accessed if we read the beginning.
2587 mark_page_accessed(page
);
2589 page
= ZERO_PAGE(0);
2594 * Ok, we have the page, and it's up-to-date, so
2595 * now we can copy it to user space...
2597 ret
= copy_page_to_iter(page
, offset
, nr
, to
);
2600 index
+= offset
>> PAGE_SHIFT
;
2601 offset
&= ~PAGE_MASK
;
2604 if (!iov_iter_count(to
))
2613 *ppos
= ((loff_t
) index
<< PAGE_SHIFT
) + offset
;
2614 file_accessed(file
);
2615 return retval
? retval
: error
;
2619 * llseek SEEK_DATA or SEEK_HOLE through the page cache.
2621 static pgoff_t
shmem_seek_hole_data(struct address_space
*mapping
,
2622 pgoff_t index
, pgoff_t end
, int whence
)
2625 struct pagevec pvec
;
2626 pgoff_t indices
[PAGEVEC_SIZE
];
2630 pagevec_init(&pvec
);
2631 pvec
.nr
= 1; /* start small: we may be there already */
2633 pvec
.nr
= find_get_entries(mapping
, index
,
2634 pvec
.nr
, pvec
.pages
, indices
);
2636 if (whence
== SEEK_DATA
)
2640 for (i
= 0; i
< pvec
.nr
; i
++, index
++) {
2641 if (index
< indices
[i
]) {
2642 if (whence
== SEEK_HOLE
) {
2648 page
= pvec
.pages
[i
];
2649 if (page
&& !xa_is_value(page
)) {
2650 if (!PageUptodate(page
))
2654 (page
&& whence
== SEEK_DATA
) ||
2655 (!page
&& whence
== SEEK_HOLE
)) {
2660 pagevec_remove_exceptionals(&pvec
);
2661 pagevec_release(&pvec
);
2662 pvec
.nr
= PAGEVEC_SIZE
;
2668 static loff_t
shmem_file_llseek(struct file
*file
, loff_t offset
, int whence
)
2670 struct address_space
*mapping
= file
->f_mapping
;
2671 struct inode
*inode
= mapping
->host
;
2675 if (whence
!= SEEK_DATA
&& whence
!= SEEK_HOLE
)
2676 return generic_file_llseek_size(file
, offset
, whence
,
2677 MAX_LFS_FILESIZE
, i_size_read(inode
));
2679 /* We're holding i_mutex so we can access i_size directly */
2681 if (offset
< 0 || offset
>= inode
->i_size
)
2684 start
= offset
>> PAGE_SHIFT
;
2685 end
= (inode
->i_size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2686 new_offset
= shmem_seek_hole_data(mapping
, start
, end
, whence
);
2687 new_offset
<<= PAGE_SHIFT
;
2688 if (new_offset
> offset
) {
2689 if (new_offset
< inode
->i_size
)
2690 offset
= new_offset
;
2691 else if (whence
== SEEK_DATA
)
2694 offset
= inode
->i_size
;
2699 offset
= vfs_setpos(file
, offset
, MAX_LFS_FILESIZE
);
2700 inode_unlock(inode
);
2704 static long shmem_fallocate(struct file
*file
, int mode
, loff_t offset
,
2707 struct inode
*inode
= file_inode(file
);
2708 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
2709 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2710 struct shmem_falloc shmem_falloc
;
2711 pgoff_t start
, index
, end
;
2714 if (mode
& ~(FALLOC_FL_KEEP_SIZE
| FALLOC_FL_PUNCH_HOLE
))
2719 if (mode
& FALLOC_FL_PUNCH_HOLE
) {
2720 struct address_space
*mapping
= file
->f_mapping
;
2721 loff_t unmap_start
= round_up(offset
, PAGE_SIZE
);
2722 loff_t unmap_end
= round_down(offset
+ len
, PAGE_SIZE
) - 1;
2723 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq
);
2725 /* protected by i_mutex */
2726 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
)) {
2731 shmem_falloc
.waitq
= &shmem_falloc_waitq
;
2732 shmem_falloc
.start
= unmap_start
>> PAGE_SHIFT
;
2733 shmem_falloc
.next
= (unmap_end
+ 1) >> PAGE_SHIFT
;
2734 spin_lock(&inode
->i_lock
);
2735 inode
->i_private
= &shmem_falloc
;
2736 spin_unlock(&inode
->i_lock
);
2738 if ((u64
)unmap_end
> (u64
)unmap_start
)
2739 unmap_mapping_range(mapping
, unmap_start
,
2740 1 + unmap_end
- unmap_start
, 0);
2741 shmem_truncate_range(inode
, offset
, offset
+ len
- 1);
2742 /* No need to unmap again: hole-punching leaves COWed pages */
2744 spin_lock(&inode
->i_lock
);
2745 inode
->i_private
= NULL
;
2746 wake_up_all(&shmem_falloc_waitq
);
2747 WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq
.head
));
2748 spin_unlock(&inode
->i_lock
);
2753 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
2754 error
= inode_newsize_ok(inode
, offset
+ len
);
2758 if ((info
->seals
& F_SEAL_GROW
) && offset
+ len
> inode
->i_size
) {
2763 start
= offset
>> PAGE_SHIFT
;
2764 end
= (offset
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2765 /* Try to avoid a swapstorm if len is impossible to satisfy */
2766 if (sbinfo
->max_blocks
&& end
- start
> sbinfo
->max_blocks
) {
2771 shmem_falloc
.waitq
= NULL
;
2772 shmem_falloc
.start
= start
;
2773 shmem_falloc
.next
= start
;
2774 shmem_falloc
.nr_falloced
= 0;
2775 shmem_falloc
.nr_unswapped
= 0;
2776 spin_lock(&inode
->i_lock
);
2777 inode
->i_private
= &shmem_falloc
;
2778 spin_unlock(&inode
->i_lock
);
2780 for (index
= start
; index
< end
; index
++) {
2784 * Good, the fallocate(2) manpage permits EINTR: we may have
2785 * been interrupted because we are using up too much memory.
2787 if (signal_pending(current
))
2789 else if (shmem_falloc
.nr_unswapped
> shmem_falloc
.nr_falloced
)
2792 error
= shmem_getpage(inode
, index
, &page
, SGP_FALLOC
);
2794 /* Remove the !PageUptodate pages we added */
2795 if (index
> start
) {
2796 shmem_undo_range(inode
,
2797 (loff_t
)start
<< PAGE_SHIFT
,
2798 ((loff_t
)index
<< PAGE_SHIFT
) - 1, true);
2804 * Inform shmem_writepage() how far we have reached.
2805 * No need for lock or barrier: we have the page lock.
2807 shmem_falloc
.next
++;
2808 if (!PageUptodate(page
))
2809 shmem_falloc
.nr_falloced
++;
2812 * If !PageUptodate, leave it that way so that freeable pages
2813 * can be recognized if we need to rollback on error later.
2814 * But set_page_dirty so that memory pressure will swap rather
2815 * than free the pages we are allocating (and SGP_CACHE pages
2816 * might still be clean: we now need to mark those dirty too).
2818 set_page_dirty(page
);
2824 if (!(mode
& FALLOC_FL_KEEP_SIZE
) && offset
+ len
> inode
->i_size
)
2825 i_size_write(inode
, offset
+ len
);
2826 inode
->i_ctime
= current_time(inode
);
2828 spin_lock(&inode
->i_lock
);
2829 inode
->i_private
= NULL
;
2830 spin_unlock(&inode
->i_lock
);
2832 inode_unlock(inode
);
2836 static int shmem_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
2838 struct shmem_sb_info
*sbinfo
= SHMEM_SB(dentry
->d_sb
);
2840 buf
->f_type
= TMPFS_MAGIC
;
2841 buf
->f_bsize
= PAGE_SIZE
;
2842 buf
->f_namelen
= NAME_MAX
;
2843 if (sbinfo
->max_blocks
) {
2844 buf
->f_blocks
= sbinfo
->max_blocks
;
2846 buf
->f_bfree
= sbinfo
->max_blocks
-
2847 percpu_counter_sum(&sbinfo
->used_blocks
);
2849 if (sbinfo
->max_inodes
) {
2850 buf
->f_files
= sbinfo
->max_inodes
;
2851 buf
->f_ffree
= sbinfo
->free_inodes
;
2853 /* else leave those fields 0 like simple_statfs */
2858 * File creation. Allocate an inode, and we're done..
2861 shmem_mknod(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
, dev_t dev
)
2863 struct inode
*inode
;
2864 int error
= -ENOSPC
;
2866 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, dev
, VM_NORESERVE
);
2868 error
= simple_acl_create(dir
, inode
);
2871 error
= security_inode_init_security(inode
, dir
,
2873 shmem_initxattrs
, NULL
);
2874 if (error
&& error
!= -EOPNOTSUPP
)
2878 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2879 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
2880 d_instantiate(dentry
, inode
);
2881 dget(dentry
); /* Extra count - pin the dentry in core */
2890 shmem_tmpfile(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
)
2892 struct inode
*inode
;
2893 int error
= -ENOSPC
;
2895 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, 0, VM_NORESERVE
);
2897 error
= security_inode_init_security(inode
, dir
,
2899 shmem_initxattrs
, NULL
);
2900 if (error
&& error
!= -EOPNOTSUPP
)
2902 error
= simple_acl_create(dir
, inode
);
2905 d_tmpfile(dentry
, inode
);
2913 static int shmem_mkdir(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
)
2917 if ((error
= shmem_mknod(dir
, dentry
, mode
| S_IFDIR
, 0)))
2923 static int shmem_create(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
,
2926 return shmem_mknod(dir
, dentry
, mode
| S_IFREG
, 0);
2932 static int shmem_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*dentry
)
2934 struct inode
*inode
= d_inode(old_dentry
);
2938 * No ordinary (disk based) filesystem counts links as inodes;
2939 * but each new link needs a new dentry, pinning lowmem, and
2940 * tmpfs dentries cannot be pruned until they are unlinked.
2941 * But if an O_TMPFILE file is linked into the tmpfs, the
2942 * first link must skip that, to get the accounting right.
2944 if (inode
->i_nlink
) {
2945 ret
= shmem_reserve_inode(inode
->i_sb
);
2950 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2951 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2953 ihold(inode
); /* New dentry reference */
2954 dget(dentry
); /* Extra pinning count for the created dentry */
2955 d_instantiate(dentry
, inode
);
2960 static int shmem_unlink(struct inode
*dir
, struct dentry
*dentry
)
2962 struct inode
*inode
= d_inode(dentry
);
2964 if (inode
->i_nlink
> 1 && !S_ISDIR(inode
->i_mode
))
2965 shmem_free_inode(inode
->i_sb
);
2967 dir
->i_size
-= BOGO_DIRENT_SIZE
;
2968 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2970 dput(dentry
); /* Undo the count from "create" - this does all the work */
2974 static int shmem_rmdir(struct inode
*dir
, struct dentry
*dentry
)
2976 if (!simple_empty(dentry
))
2979 drop_nlink(d_inode(dentry
));
2981 return shmem_unlink(dir
, dentry
);
2984 static int shmem_exchange(struct inode
*old_dir
, struct dentry
*old_dentry
, struct inode
*new_dir
, struct dentry
*new_dentry
)
2986 bool old_is_dir
= d_is_dir(old_dentry
);
2987 bool new_is_dir
= d_is_dir(new_dentry
);
2989 if (old_dir
!= new_dir
&& old_is_dir
!= new_is_dir
) {
2991 drop_nlink(old_dir
);
2994 drop_nlink(new_dir
);
2998 old_dir
->i_ctime
= old_dir
->i_mtime
=
2999 new_dir
->i_ctime
= new_dir
->i_mtime
=
3000 d_inode(old_dentry
)->i_ctime
=
3001 d_inode(new_dentry
)->i_ctime
= current_time(old_dir
);
3006 static int shmem_whiteout(struct inode
*old_dir
, struct dentry
*old_dentry
)
3008 struct dentry
*whiteout
;
3011 whiteout
= d_alloc(old_dentry
->d_parent
, &old_dentry
->d_name
);
3015 error
= shmem_mknod(old_dir
, whiteout
,
3016 S_IFCHR
| WHITEOUT_MODE
, WHITEOUT_DEV
);
3022 * Cheat and hash the whiteout while the old dentry is still in
3023 * place, instead of playing games with FS_RENAME_DOES_D_MOVE.
3025 * d_lookup() will consistently find one of them at this point,
3026 * not sure which one, but that isn't even important.
3033 * The VFS layer already does all the dentry stuff for rename,
3034 * we just have to decrement the usage count for the target if
3035 * it exists so that the VFS layer correctly free's it when it
3038 static int shmem_rename2(struct inode
*old_dir
, struct dentry
*old_dentry
, struct inode
*new_dir
, struct dentry
*new_dentry
, unsigned int flags
)
3040 struct inode
*inode
= d_inode(old_dentry
);
3041 int they_are_dirs
= S_ISDIR(inode
->i_mode
);
3043 if (flags
& ~(RENAME_NOREPLACE
| RENAME_EXCHANGE
| RENAME_WHITEOUT
))
3046 if (flags
& RENAME_EXCHANGE
)
3047 return shmem_exchange(old_dir
, old_dentry
, new_dir
, new_dentry
);
3049 if (!simple_empty(new_dentry
))
3052 if (flags
& RENAME_WHITEOUT
) {
3055 error
= shmem_whiteout(old_dir
, old_dentry
);
3060 if (d_really_is_positive(new_dentry
)) {
3061 (void) shmem_unlink(new_dir
, new_dentry
);
3062 if (they_are_dirs
) {
3063 drop_nlink(d_inode(new_dentry
));
3064 drop_nlink(old_dir
);
3066 } else if (they_are_dirs
) {
3067 drop_nlink(old_dir
);
3071 old_dir
->i_size
-= BOGO_DIRENT_SIZE
;
3072 new_dir
->i_size
+= BOGO_DIRENT_SIZE
;
3073 old_dir
->i_ctime
= old_dir
->i_mtime
=
3074 new_dir
->i_ctime
= new_dir
->i_mtime
=
3075 inode
->i_ctime
= current_time(old_dir
);
3079 static int shmem_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *symname
)
3083 struct inode
*inode
;
3086 len
= strlen(symname
) + 1;
3087 if (len
> PAGE_SIZE
)
3088 return -ENAMETOOLONG
;
3090 inode
= shmem_get_inode(dir
->i_sb
, dir
, S_IFLNK
| 0777, 0,
3095 error
= security_inode_init_security(inode
, dir
, &dentry
->d_name
,
3096 shmem_initxattrs
, NULL
);
3098 if (error
!= -EOPNOTSUPP
) {
3105 inode
->i_size
= len
-1;
3106 if (len
<= SHORT_SYMLINK_LEN
) {
3107 inode
->i_link
= kmemdup(symname
, len
, GFP_KERNEL
);
3108 if (!inode
->i_link
) {
3112 inode
->i_op
= &shmem_short_symlink_operations
;
3114 inode_nohighmem(inode
);
3115 error
= shmem_getpage(inode
, 0, &page
, SGP_WRITE
);
3120 inode
->i_mapping
->a_ops
= &shmem_aops
;
3121 inode
->i_op
= &shmem_symlink_inode_operations
;
3122 memcpy(page_address(page
), symname
, len
);
3123 SetPageUptodate(page
);
3124 set_page_dirty(page
);
3128 dir
->i_size
+= BOGO_DIRENT_SIZE
;
3129 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
3130 d_instantiate(dentry
, inode
);
3135 static void shmem_put_link(void *arg
)
3137 mark_page_accessed(arg
);
3141 static const char *shmem_get_link(struct dentry
*dentry
,
3142 struct inode
*inode
,
3143 struct delayed_call
*done
)
3145 struct page
*page
= NULL
;
3148 page
= find_get_page(inode
->i_mapping
, 0);
3150 return ERR_PTR(-ECHILD
);
3151 if (!PageUptodate(page
)) {
3153 return ERR_PTR(-ECHILD
);
3156 error
= shmem_getpage(inode
, 0, &page
, SGP_READ
);
3158 return ERR_PTR(error
);
3161 set_delayed_call(done
, shmem_put_link
, page
);
3162 return page_address(page
);
3165 #ifdef CONFIG_TMPFS_XATTR
3167 * Superblocks without xattr inode operations may get some security.* xattr
3168 * support from the LSM "for free". As soon as we have any other xattrs
3169 * like ACLs, we also need to implement the security.* handlers at
3170 * filesystem level, though.
3174 * Callback for security_inode_init_security() for acquiring xattrs.
3176 static int shmem_initxattrs(struct inode
*inode
,
3177 const struct xattr
*xattr_array
,
3180 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3181 const struct xattr
*xattr
;
3182 struct simple_xattr
*new_xattr
;
3185 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
3186 new_xattr
= simple_xattr_alloc(xattr
->value
, xattr
->value_len
);
3190 len
= strlen(xattr
->name
) + 1;
3191 new_xattr
->name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+ len
,
3193 if (!new_xattr
->name
) {
3198 memcpy(new_xattr
->name
, XATTR_SECURITY_PREFIX
,
3199 XATTR_SECURITY_PREFIX_LEN
);
3200 memcpy(new_xattr
->name
+ XATTR_SECURITY_PREFIX_LEN
,
3203 simple_xattr_list_add(&info
->xattrs
, new_xattr
);
3209 static int shmem_xattr_handler_get(const struct xattr_handler
*handler
,
3210 struct dentry
*unused
, struct inode
*inode
,
3211 const char *name
, void *buffer
, size_t size
)
3213 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3215 name
= xattr_full_name(handler
, name
);
3216 return simple_xattr_get(&info
->xattrs
, name
, buffer
, size
);
3219 static int shmem_xattr_handler_set(const struct xattr_handler
*handler
,
3220 struct dentry
*unused
, struct inode
*inode
,
3221 const char *name
, const void *value
,
3222 size_t size
, int flags
)
3224 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3226 name
= xattr_full_name(handler
, name
);
3227 return simple_xattr_set(&info
->xattrs
, name
, value
, size
, flags
);
3230 static const struct xattr_handler shmem_security_xattr_handler
= {
3231 .prefix
= XATTR_SECURITY_PREFIX
,
3232 .get
= shmem_xattr_handler_get
,
3233 .set
= shmem_xattr_handler_set
,
3236 static const struct xattr_handler shmem_trusted_xattr_handler
= {
3237 .prefix
= XATTR_TRUSTED_PREFIX
,
3238 .get
= shmem_xattr_handler_get
,
3239 .set
= shmem_xattr_handler_set
,
3242 static const struct xattr_handler
*shmem_xattr_handlers
[] = {
3243 #ifdef CONFIG_TMPFS_POSIX_ACL
3244 &posix_acl_access_xattr_handler
,
3245 &posix_acl_default_xattr_handler
,
3247 &shmem_security_xattr_handler
,
3248 &shmem_trusted_xattr_handler
,
3252 static ssize_t
shmem_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
3254 struct shmem_inode_info
*info
= SHMEM_I(d_inode(dentry
));
3255 return simple_xattr_list(d_inode(dentry
), &info
->xattrs
, buffer
, size
);
3257 #endif /* CONFIG_TMPFS_XATTR */
3259 static const struct inode_operations shmem_short_symlink_operations
= {
3260 .get_link
= simple_get_link
,
3261 #ifdef CONFIG_TMPFS_XATTR
3262 .listxattr
= shmem_listxattr
,
3266 static const struct inode_operations shmem_symlink_inode_operations
= {
3267 .get_link
= shmem_get_link
,
3268 #ifdef CONFIG_TMPFS_XATTR
3269 .listxattr
= shmem_listxattr
,
3273 static struct dentry
*shmem_get_parent(struct dentry
*child
)
3275 return ERR_PTR(-ESTALE
);
3278 static int shmem_match(struct inode
*ino
, void *vfh
)
3282 inum
= (inum
<< 32) | fh
[1];
3283 return ino
->i_ino
== inum
&& fh
[0] == ino
->i_generation
;
3286 /* Find any alias of inode, but prefer a hashed alias */
3287 static struct dentry
*shmem_find_alias(struct inode
*inode
)
3289 struct dentry
*alias
= d_find_alias(inode
);
3291 return alias
?: d_find_any_alias(inode
);
3295 static struct dentry
*shmem_fh_to_dentry(struct super_block
*sb
,
3296 struct fid
*fid
, int fh_len
, int fh_type
)
3298 struct inode
*inode
;
3299 struct dentry
*dentry
= NULL
;
3306 inum
= (inum
<< 32) | fid
->raw
[1];
3308 inode
= ilookup5(sb
, (unsigned long)(inum
+ fid
->raw
[0]),
3309 shmem_match
, fid
->raw
);
3311 dentry
= shmem_find_alias(inode
);
3318 static int shmem_encode_fh(struct inode
*inode
, __u32
*fh
, int *len
,
3319 struct inode
*parent
)
3323 return FILEID_INVALID
;
3326 if (inode_unhashed(inode
)) {
3327 /* Unfortunately insert_inode_hash is not idempotent,
3328 * so as we hash inodes here rather than at creation
3329 * time, we need a lock to ensure we only try
3332 static DEFINE_SPINLOCK(lock
);
3334 if (inode_unhashed(inode
))
3335 __insert_inode_hash(inode
,
3336 inode
->i_ino
+ inode
->i_generation
);
3340 fh
[0] = inode
->i_generation
;
3341 fh
[1] = inode
->i_ino
;
3342 fh
[2] = ((__u64
)inode
->i_ino
) >> 32;
3348 static const struct export_operations shmem_export_ops
= {
3349 .get_parent
= shmem_get_parent
,
3350 .encode_fh
= shmem_encode_fh
,
3351 .fh_to_dentry
= shmem_fh_to_dentry
,
3354 static int shmem_parse_options(char *options
, struct shmem_sb_info
*sbinfo
,
3357 char *this_char
, *value
, *rest
;
3358 struct mempolicy
*mpol
= NULL
;
3362 while (options
!= NULL
) {
3363 this_char
= options
;
3366 * NUL-terminate this option: unfortunately,
3367 * mount options form a comma-separated list,
3368 * but mpol's nodelist may also contain commas.
3370 options
= strchr(options
, ',');
3371 if (options
== NULL
)
3374 if (!isdigit(*options
)) {
3381 if ((value
= strchr(this_char
,'=')) != NULL
) {
3384 pr_err("tmpfs: No value for mount option '%s'\n",
3389 if (!strcmp(this_char
,"size")) {
3390 unsigned long long size
;
3391 size
= memparse(value
,&rest
);
3393 size
<<= PAGE_SHIFT
;
3394 size
*= totalram_pages();
3400 sbinfo
->max_blocks
=
3401 DIV_ROUND_UP(size
, PAGE_SIZE
);
3402 } else if (!strcmp(this_char
,"nr_blocks")) {
3403 sbinfo
->max_blocks
= memparse(value
, &rest
);
3406 } else if (!strcmp(this_char
,"nr_inodes")) {
3407 sbinfo
->max_inodes
= memparse(value
, &rest
);
3410 } else if (!strcmp(this_char
,"mode")) {
3413 sbinfo
->mode
= simple_strtoul(value
, &rest
, 8) & 07777;
3416 } else if (!strcmp(this_char
,"uid")) {
3419 uid
= simple_strtoul(value
, &rest
, 0);
3422 sbinfo
->uid
= make_kuid(current_user_ns(), uid
);
3423 if (!uid_valid(sbinfo
->uid
))
3425 } else if (!strcmp(this_char
,"gid")) {
3428 gid
= simple_strtoul(value
, &rest
, 0);
3431 sbinfo
->gid
= make_kgid(current_user_ns(), gid
);
3432 if (!gid_valid(sbinfo
->gid
))
3434 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3435 } else if (!strcmp(this_char
, "huge")) {
3437 huge
= shmem_parse_huge(value
);
3440 if (!has_transparent_hugepage() &&
3441 huge
!= SHMEM_HUGE_NEVER
)
3443 sbinfo
->huge
= huge
;
3446 } else if (!strcmp(this_char
,"mpol")) {
3449 if (mpol_parse_str(value
, &mpol
))
3453 pr_err("tmpfs: Bad mount option %s\n", this_char
);
3457 sbinfo
->mpol
= mpol
;
3461 pr_err("tmpfs: Bad value '%s' for mount option '%s'\n",
3469 static int shmem_remount_fs(struct super_block
*sb
, int *flags
, char *data
)
3471 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
3472 struct shmem_sb_info config
= *sbinfo
;
3473 unsigned long inodes
;
3474 int error
= -EINVAL
;
3477 if (shmem_parse_options(data
, &config
, true))
3480 spin_lock(&sbinfo
->stat_lock
);
3481 inodes
= sbinfo
->max_inodes
- sbinfo
->free_inodes
;
3482 if (percpu_counter_compare(&sbinfo
->used_blocks
, config
.max_blocks
) > 0)
3484 if (config
.max_inodes
< inodes
)
3487 * Those tests disallow limited->unlimited while any are in use;
3488 * but we must separately disallow unlimited->limited, because
3489 * in that case we have no record of how much is already in use.
3491 if (config
.max_blocks
&& !sbinfo
->max_blocks
)
3493 if (config
.max_inodes
&& !sbinfo
->max_inodes
)
3497 sbinfo
->huge
= config
.huge
;
3498 sbinfo
->max_blocks
= config
.max_blocks
;
3499 sbinfo
->max_inodes
= config
.max_inodes
;
3500 sbinfo
->free_inodes
= config
.max_inodes
- inodes
;
3503 * Preserve previous mempolicy unless mpol remount option was specified.
3506 mpol_put(sbinfo
->mpol
);
3507 sbinfo
->mpol
= config
.mpol
; /* transfers initial ref */
3510 spin_unlock(&sbinfo
->stat_lock
);
3514 static int shmem_show_options(struct seq_file
*seq
, struct dentry
*root
)
3516 struct shmem_sb_info
*sbinfo
= SHMEM_SB(root
->d_sb
);
3518 if (sbinfo
->max_blocks
!= shmem_default_max_blocks())
3519 seq_printf(seq
, ",size=%luk",
3520 sbinfo
->max_blocks
<< (PAGE_SHIFT
- 10));
3521 if (sbinfo
->max_inodes
!= shmem_default_max_inodes())
3522 seq_printf(seq
, ",nr_inodes=%lu", sbinfo
->max_inodes
);
3523 if (sbinfo
->mode
!= (0777 | S_ISVTX
))
3524 seq_printf(seq
, ",mode=%03ho", sbinfo
->mode
);
3525 if (!uid_eq(sbinfo
->uid
, GLOBAL_ROOT_UID
))
3526 seq_printf(seq
, ",uid=%u",
3527 from_kuid_munged(&init_user_ns
, sbinfo
->uid
));
3528 if (!gid_eq(sbinfo
->gid
, GLOBAL_ROOT_GID
))
3529 seq_printf(seq
, ",gid=%u",
3530 from_kgid_munged(&init_user_ns
, sbinfo
->gid
));
3531 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3532 /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
3534 seq_printf(seq
, ",huge=%s", shmem_format_huge(sbinfo
->huge
));
3536 shmem_show_mpol(seq
, sbinfo
->mpol
);
3540 #endif /* CONFIG_TMPFS */
3542 static void shmem_put_super(struct super_block
*sb
)
3544 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
3546 percpu_counter_destroy(&sbinfo
->used_blocks
);
3547 mpol_put(sbinfo
->mpol
);
3549 sb
->s_fs_info
= NULL
;
3552 int shmem_fill_super(struct super_block
*sb
, void *data
, int silent
)
3554 struct inode
*inode
;
3555 struct shmem_sb_info
*sbinfo
;
3558 /* Round up to L1_CACHE_BYTES to resist false sharing */
3559 sbinfo
= kzalloc(max((int)sizeof(struct shmem_sb_info
),
3560 L1_CACHE_BYTES
), GFP_KERNEL
);
3564 sbinfo
->mode
= 0777 | S_ISVTX
;
3565 sbinfo
->uid
= current_fsuid();
3566 sbinfo
->gid
= current_fsgid();
3567 sb
->s_fs_info
= sbinfo
;
3571 * Per default we only allow half of the physical ram per
3572 * tmpfs instance, limiting inodes to one per page of lowmem;
3573 * but the internal instance is left unlimited.
3575 if (!(sb
->s_flags
& SB_KERNMOUNT
)) {
3576 sbinfo
->max_blocks
= shmem_default_max_blocks();
3577 sbinfo
->max_inodes
= shmem_default_max_inodes();
3578 if (shmem_parse_options(data
, sbinfo
, false)) {
3583 sb
->s_flags
|= SB_NOUSER
;
3585 sb
->s_export_op
= &shmem_export_ops
;
3586 sb
->s_flags
|= SB_NOSEC
;
3588 sb
->s_flags
|= SB_NOUSER
;
3591 spin_lock_init(&sbinfo
->stat_lock
);
3592 if (percpu_counter_init(&sbinfo
->used_blocks
, 0, GFP_KERNEL
))
3594 sbinfo
->free_inodes
= sbinfo
->max_inodes
;
3595 spin_lock_init(&sbinfo
->shrinklist_lock
);
3596 INIT_LIST_HEAD(&sbinfo
->shrinklist
);
3598 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
3599 sb
->s_blocksize
= PAGE_SIZE
;
3600 sb
->s_blocksize_bits
= PAGE_SHIFT
;
3601 sb
->s_magic
= TMPFS_MAGIC
;
3602 sb
->s_op
= &shmem_ops
;
3603 sb
->s_time_gran
= 1;
3604 #ifdef CONFIG_TMPFS_XATTR
3605 sb
->s_xattr
= shmem_xattr_handlers
;
3607 #ifdef CONFIG_TMPFS_POSIX_ACL
3608 sb
->s_flags
|= SB_POSIXACL
;
3610 uuid_gen(&sb
->s_uuid
);
3612 inode
= shmem_get_inode(sb
, NULL
, S_IFDIR
| sbinfo
->mode
, 0, VM_NORESERVE
);
3615 inode
->i_uid
= sbinfo
->uid
;
3616 inode
->i_gid
= sbinfo
->gid
;
3617 sb
->s_root
= d_make_root(inode
);
3623 shmem_put_super(sb
);
3627 static struct kmem_cache
*shmem_inode_cachep
;
3629 static struct inode
*shmem_alloc_inode(struct super_block
*sb
)
3631 struct shmem_inode_info
*info
;
3632 info
= kmem_cache_alloc(shmem_inode_cachep
, GFP_KERNEL
);
3635 return &info
->vfs_inode
;
3638 static void shmem_destroy_callback(struct rcu_head
*head
)
3640 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
3641 if (S_ISLNK(inode
->i_mode
))
3642 kfree(inode
->i_link
);
3643 kmem_cache_free(shmem_inode_cachep
, SHMEM_I(inode
));
3646 static void shmem_destroy_inode(struct inode
*inode
)
3648 if (S_ISREG(inode
->i_mode
))
3649 mpol_free_shared_policy(&SHMEM_I(inode
)->policy
);
3650 call_rcu(&inode
->i_rcu
, shmem_destroy_callback
);
3653 static void shmem_init_inode(void *foo
)
3655 struct shmem_inode_info
*info
= foo
;
3656 inode_init_once(&info
->vfs_inode
);
3659 static void shmem_init_inodecache(void)
3661 shmem_inode_cachep
= kmem_cache_create("shmem_inode_cache",
3662 sizeof(struct shmem_inode_info
),
3663 0, SLAB_PANIC
|SLAB_ACCOUNT
, shmem_init_inode
);
3666 static void shmem_destroy_inodecache(void)
3668 kmem_cache_destroy(shmem_inode_cachep
);
3671 static const struct address_space_operations shmem_aops
= {
3672 .writepage
= shmem_writepage
,
3673 .set_page_dirty
= __set_page_dirty_no_writeback
,
3675 .write_begin
= shmem_write_begin
,
3676 .write_end
= shmem_write_end
,
3678 #ifdef CONFIG_MIGRATION
3679 .migratepage
= migrate_page
,
3681 .error_remove_page
= generic_error_remove_page
,
3684 static const struct file_operations shmem_file_operations
= {
3686 .get_unmapped_area
= shmem_get_unmapped_area
,
3688 .llseek
= shmem_file_llseek
,
3689 .read_iter
= shmem_file_read_iter
,
3690 .write_iter
= generic_file_write_iter
,
3691 .fsync
= noop_fsync
,
3692 .splice_read
= generic_file_splice_read
,
3693 .splice_write
= iter_file_splice_write
,
3694 .fallocate
= shmem_fallocate
,
3698 static const struct inode_operations shmem_inode_operations
= {
3699 .getattr
= shmem_getattr
,
3700 .setattr
= shmem_setattr
,
3701 #ifdef CONFIG_TMPFS_XATTR
3702 .listxattr
= shmem_listxattr
,
3703 .set_acl
= simple_set_acl
,
3707 static const struct inode_operations shmem_dir_inode_operations
= {
3709 .create
= shmem_create
,
3710 .lookup
= simple_lookup
,
3712 .unlink
= shmem_unlink
,
3713 .symlink
= shmem_symlink
,
3714 .mkdir
= shmem_mkdir
,
3715 .rmdir
= shmem_rmdir
,
3716 .mknod
= shmem_mknod
,
3717 .rename
= shmem_rename2
,
3718 .tmpfile
= shmem_tmpfile
,
3720 #ifdef CONFIG_TMPFS_XATTR
3721 .listxattr
= shmem_listxattr
,
3723 #ifdef CONFIG_TMPFS_POSIX_ACL
3724 .setattr
= shmem_setattr
,
3725 .set_acl
= simple_set_acl
,
3729 static const struct inode_operations shmem_special_inode_operations
= {
3730 #ifdef CONFIG_TMPFS_XATTR
3731 .listxattr
= shmem_listxattr
,
3733 #ifdef CONFIG_TMPFS_POSIX_ACL
3734 .setattr
= shmem_setattr
,
3735 .set_acl
= simple_set_acl
,
3739 static const struct super_operations shmem_ops
= {
3740 .alloc_inode
= shmem_alloc_inode
,
3741 .destroy_inode
= shmem_destroy_inode
,
3743 .statfs
= shmem_statfs
,
3744 .remount_fs
= shmem_remount_fs
,
3745 .show_options
= shmem_show_options
,
3747 .evict_inode
= shmem_evict_inode
,
3748 .drop_inode
= generic_delete_inode
,
3749 .put_super
= shmem_put_super
,
3750 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3751 .nr_cached_objects
= shmem_unused_huge_count
,
3752 .free_cached_objects
= shmem_unused_huge_scan
,
3756 static const struct vm_operations_struct shmem_vm_ops
= {
3757 .fault
= shmem_fault
,
3758 .map_pages
= filemap_map_pages
,
3760 .set_policy
= shmem_set_policy
,
3761 .get_policy
= shmem_get_policy
,
3765 static struct dentry
*shmem_mount(struct file_system_type
*fs_type
,
3766 int flags
, const char *dev_name
, void *data
)
3768 return mount_nodev(fs_type
, flags
, data
, shmem_fill_super
);
3771 static struct file_system_type shmem_fs_type
= {
3772 .owner
= THIS_MODULE
,
3774 .mount
= shmem_mount
,
3775 .kill_sb
= kill_litter_super
,
3776 .fs_flags
= FS_USERNS_MOUNT
,
3779 int __init
shmem_init(void)
3783 /* If rootfs called this, don't re-init */
3784 if (shmem_inode_cachep
)
3787 shmem_init_inodecache();
3789 error
= register_filesystem(&shmem_fs_type
);
3791 pr_err("Could not register tmpfs\n");
3795 shm_mnt
= kern_mount(&shmem_fs_type
);
3796 if (IS_ERR(shm_mnt
)) {
3797 error
= PTR_ERR(shm_mnt
);
3798 pr_err("Could not kern_mount tmpfs\n");
3802 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3803 if (has_transparent_hugepage() && shmem_huge
> SHMEM_HUGE_DENY
)
3804 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3806 shmem_huge
= 0; /* just in case it was patched */
3811 unregister_filesystem(&shmem_fs_type
);
3813 shmem_destroy_inodecache();
3814 shm_mnt
= ERR_PTR(error
);
3818 #if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && defined(CONFIG_SYSFS)
3819 static ssize_t
shmem_enabled_show(struct kobject
*kobj
,
3820 struct kobj_attribute
*attr
, char *buf
)
3824 SHMEM_HUGE_WITHIN_SIZE
,
3832 for (i
= 0, count
= 0; i
< ARRAY_SIZE(values
); i
++) {
3833 const char *fmt
= shmem_huge
== values
[i
] ? "[%s] " : "%s ";
3835 count
+= sprintf(buf
+ count
, fmt
,
3836 shmem_format_huge(values
[i
]));
3838 buf
[count
- 1] = '\n';
3842 static ssize_t
shmem_enabled_store(struct kobject
*kobj
,
3843 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
3848 if (count
+ 1 > sizeof(tmp
))
3850 memcpy(tmp
, buf
, count
);
3852 if (count
&& tmp
[count
- 1] == '\n')
3853 tmp
[count
- 1] = '\0';
3855 huge
= shmem_parse_huge(tmp
);
3856 if (huge
== -EINVAL
)
3858 if (!has_transparent_hugepage() &&
3859 huge
!= SHMEM_HUGE_NEVER
&& huge
!= SHMEM_HUGE_DENY
)
3863 if (shmem_huge
> SHMEM_HUGE_DENY
)
3864 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3868 struct kobj_attribute shmem_enabled_attr
=
3869 __ATTR(shmem_enabled
, 0644, shmem_enabled_show
, shmem_enabled_store
);
3870 #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */
3872 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3873 bool shmem_huge_enabled(struct vm_area_struct
*vma
)
3875 struct inode
*inode
= file_inode(vma
->vm_file
);
3876 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
3880 if (shmem_huge
== SHMEM_HUGE_FORCE
)
3882 if (shmem_huge
== SHMEM_HUGE_DENY
)
3884 switch (sbinfo
->huge
) {
3885 case SHMEM_HUGE_NEVER
:
3887 case SHMEM_HUGE_ALWAYS
:
3889 case SHMEM_HUGE_WITHIN_SIZE
:
3890 off
= round_up(vma
->vm_pgoff
, HPAGE_PMD_NR
);
3891 i_size
= round_up(i_size_read(inode
), PAGE_SIZE
);
3892 if (i_size
>= HPAGE_PMD_SIZE
&&
3893 i_size
>> PAGE_SHIFT
>= off
)
3896 case SHMEM_HUGE_ADVISE
:
3897 /* TODO: implement fadvise() hints */
3898 return (vma
->vm_flags
& VM_HUGEPAGE
);
3904 #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */
3906 #else /* !CONFIG_SHMEM */
3909 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
3911 * This is intended for small system where the benefits of the full
3912 * shmem code (swap-backed and resource-limited) are outweighed by
3913 * their complexity. On systems without swap this code should be
3914 * effectively equivalent, but much lighter weight.
3917 static struct file_system_type shmem_fs_type
= {
3919 .mount
= ramfs_mount
,
3920 .kill_sb
= kill_litter_super
,
3921 .fs_flags
= FS_USERNS_MOUNT
,
3924 int __init
shmem_init(void)
3926 BUG_ON(register_filesystem(&shmem_fs_type
) != 0);
3928 shm_mnt
= kern_mount(&shmem_fs_type
);
3929 BUG_ON(IS_ERR(shm_mnt
));
3934 int shmem_unuse(unsigned int type
, bool frontswap
,
3935 unsigned long *fs_pages_to_unuse
)
3940 int shmem_lock(struct file
*file
, int lock
, struct user_struct
*user
)
3945 void shmem_unlock_mapping(struct address_space
*mapping
)
3950 unsigned long shmem_get_unmapped_area(struct file
*file
,
3951 unsigned long addr
, unsigned long len
,
3952 unsigned long pgoff
, unsigned long flags
)
3954 return current
->mm
->get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
3958 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
3960 truncate_inode_pages_range(inode
->i_mapping
, lstart
, lend
);
3962 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
3964 #define shmem_vm_ops generic_file_vm_ops
3965 #define shmem_file_operations ramfs_file_operations
3966 #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
3967 #define shmem_acct_size(flags, size) 0
3968 #define shmem_unacct_size(flags, size) do {} while (0)
3970 #endif /* CONFIG_SHMEM */
3974 static struct file
*__shmem_file_setup(struct vfsmount
*mnt
, const char *name
, loff_t size
,
3975 unsigned long flags
, unsigned int i_flags
)
3977 struct inode
*inode
;
3981 return ERR_CAST(mnt
);
3983 if (size
< 0 || size
> MAX_LFS_FILESIZE
)
3984 return ERR_PTR(-EINVAL
);
3986 if (shmem_acct_size(flags
, size
))
3987 return ERR_PTR(-ENOMEM
);
3989 inode
= shmem_get_inode(mnt
->mnt_sb
, NULL
, S_IFREG
| S_IRWXUGO
, 0,
3991 if (unlikely(!inode
)) {
3992 shmem_unacct_size(flags
, size
);
3993 return ERR_PTR(-ENOSPC
);
3995 inode
->i_flags
|= i_flags
;
3996 inode
->i_size
= size
;
3997 clear_nlink(inode
); /* It is unlinked */
3998 res
= ERR_PTR(ramfs_nommu_expand_for_mapping(inode
, size
));
4000 res
= alloc_file_pseudo(inode
, mnt
, name
, O_RDWR
,
4001 &shmem_file_operations
);
4008 * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
4009 * kernel internal. There will be NO LSM permission checks against the
4010 * underlying inode. So users of this interface must do LSM checks at a
4011 * higher layer. The users are the big_key and shm implementations. LSM
4012 * checks are provided at the key or shm level rather than the inode.
4013 * @name: name for dentry (to be seen in /proc/<pid>/maps
4014 * @size: size to be set for the file
4015 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4017 struct file
*shmem_kernel_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4019 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, S_PRIVATE
);
4023 * shmem_file_setup - get an unlinked file living in tmpfs
4024 * @name: name for dentry (to be seen in /proc/<pid>/maps
4025 * @size: size to be set for the file
4026 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4028 struct file
*shmem_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4030 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, 0);
4032 EXPORT_SYMBOL_GPL(shmem_file_setup
);
4035 * shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
4036 * @mnt: the tmpfs mount where the file will be created
4037 * @name: name for dentry (to be seen in /proc/<pid>/maps
4038 * @size: size to be set for the file
4039 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4041 struct file
*shmem_file_setup_with_mnt(struct vfsmount
*mnt
, const char *name
,
4042 loff_t size
, unsigned long flags
)
4044 return __shmem_file_setup(mnt
, name
, size
, flags
, 0);
4046 EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt
);
4049 * shmem_zero_setup - setup a shared anonymous mapping
4050 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
4052 int shmem_zero_setup(struct vm_area_struct
*vma
)
4055 loff_t size
= vma
->vm_end
- vma
->vm_start
;
4058 * Cloning a new file under mmap_sem leads to a lock ordering conflict
4059 * between XFS directory reading and selinux: since this file is only
4060 * accessible to the user through its mapping, use S_PRIVATE flag to
4061 * bypass file security, in the same way as shmem_kernel_file_setup().
4063 file
= shmem_kernel_file_setup("dev/zero", size
, vma
->vm_flags
);
4065 return PTR_ERR(file
);
4069 vma
->vm_file
= file
;
4070 vma
->vm_ops
= &shmem_vm_ops
;
4072 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
) &&
4073 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
4074 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
4075 khugepaged_enter(vma
, vma
->vm_flags
);
4082 * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
4083 * @mapping: the page's address_space
4084 * @index: the page index
4085 * @gfp: the page allocator flags to use if allocating
4087 * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
4088 * with any new page allocations done using the specified allocation flags.
4089 * But read_cache_page_gfp() uses the ->readpage() method: which does not
4090 * suit tmpfs, since it may have pages in swapcache, and needs to find those
4091 * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
4093 * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
4094 * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
4096 struct page
*shmem_read_mapping_page_gfp(struct address_space
*mapping
,
4097 pgoff_t index
, gfp_t gfp
)
4100 struct inode
*inode
= mapping
->host
;
4104 BUG_ON(mapping
->a_ops
!= &shmem_aops
);
4105 error
= shmem_getpage_gfp(inode
, index
, &page
, SGP_CACHE
,
4106 gfp
, NULL
, NULL
, NULL
);
4108 page
= ERR_PTR(error
);
4114 * The tiny !SHMEM case uses ramfs without swap
4116 return read_cache_page_gfp(mapping
, index
, gfp
);
4119 EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp
);