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>
40 #include <linux/fs_parser.h>
42 #include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */
44 static struct vfsmount
*shm_mnt
;
48 * This virtual memory filesystem is heavily based on the ramfs. It
49 * extends ramfs by the ability to use swap and honor resource limits
50 * which makes it a completely usable filesystem.
53 #include <linux/xattr.h>
54 #include <linux/exportfs.h>
55 #include <linux/posix_acl.h>
56 #include <linux/posix_acl_xattr.h>
57 #include <linux/mman.h>
58 #include <linux/string.h>
59 #include <linux/slab.h>
60 #include <linux/backing-dev.h>
61 #include <linux/shmem_fs.h>
62 #include <linux/writeback.h>
63 #include <linux/blkdev.h>
64 #include <linux/pagevec.h>
65 #include <linux/percpu_counter.h>
66 #include <linux/falloc.h>
67 #include <linux/splice.h>
68 #include <linux/security.h>
69 #include <linux/swapops.h>
70 #include <linux/mempolicy.h>
71 #include <linux/namei.h>
72 #include <linux/ctype.h>
73 #include <linux/migrate.h>
74 #include <linux/highmem.h>
75 #include <linux/seq_file.h>
76 #include <linux/magic.h>
77 #include <linux/syscalls.h>
78 #include <linux/fcntl.h>
79 #include <uapi/linux/memfd.h>
80 #include <linux/userfaultfd_k.h>
81 #include <linux/rmap.h>
82 #include <linux/uuid.h>
84 #include <linux/uaccess.h>
85 #include <asm/pgtable.h>
89 #define BLOCKS_PER_PAGE (PAGE_SIZE/512)
90 #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
92 /* Pretend that each entry is of this size in directory's i_size */
93 #define BOGO_DIRENT_SIZE 20
95 /* Symlink up to this size is kmalloc'ed instead of using a swappable page */
96 #define SHORT_SYMLINK_LEN 128
99 * shmem_fallocate communicates with shmem_fault or shmem_writepage via
100 * inode->i_private (with i_mutex making sure that it has only one user at
101 * a time): we would prefer not to enlarge the shmem inode just for that.
103 struct shmem_falloc
{
104 wait_queue_head_t
*waitq
; /* faults into hole wait for punch to end */
105 pgoff_t start
; /* start of range currently being fallocated */
106 pgoff_t next
; /* the next page offset to be fallocated */
107 pgoff_t nr_falloced
; /* how many new pages have been fallocated */
108 pgoff_t nr_unswapped
; /* how often writepage refused to swap out */
111 struct shmem_options
{
112 unsigned long long blocks
;
113 unsigned long long inodes
;
114 struct mempolicy
*mpol
;
120 #define SHMEM_SEEN_BLOCKS 1
121 #define SHMEM_SEEN_INODES 2
122 #define SHMEM_SEEN_HUGE 4
126 static unsigned long shmem_default_max_blocks(void)
128 return totalram_pages() / 2;
131 static unsigned long shmem_default_max_inodes(void)
133 unsigned long nr_pages
= totalram_pages();
135 return min(nr_pages
- totalhigh_pages(), nr_pages
/ 2);
139 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
);
140 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
141 struct shmem_inode_info
*info
, pgoff_t index
);
142 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
143 struct page
**pagep
, enum sgp_type sgp
,
144 gfp_t gfp
, struct vm_area_struct
*vma
,
145 vm_fault_t
*fault_type
);
146 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
147 struct page
**pagep
, enum sgp_type sgp
,
148 gfp_t gfp
, struct vm_area_struct
*vma
,
149 struct vm_fault
*vmf
, vm_fault_t
*fault_type
);
151 int shmem_getpage(struct inode
*inode
, pgoff_t index
,
152 struct page
**pagep
, enum sgp_type sgp
)
154 return shmem_getpage_gfp(inode
, index
, pagep
, sgp
,
155 mapping_gfp_mask(inode
->i_mapping
), NULL
, NULL
, NULL
);
158 static inline struct shmem_sb_info
*SHMEM_SB(struct super_block
*sb
)
160 return sb
->s_fs_info
;
164 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
165 * for shared memory and for shared anonymous (/dev/zero) mappings
166 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
167 * consistent with the pre-accounting of private mappings ...
169 static inline int shmem_acct_size(unsigned long flags
, loff_t size
)
171 return (flags
& VM_NORESERVE
) ?
172 0 : security_vm_enough_memory_mm(current
->mm
, VM_ACCT(size
));
175 static inline void shmem_unacct_size(unsigned long flags
, loff_t size
)
177 if (!(flags
& VM_NORESERVE
))
178 vm_unacct_memory(VM_ACCT(size
));
181 static inline int shmem_reacct_size(unsigned long flags
,
182 loff_t oldsize
, loff_t newsize
)
184 if (!(flags
& VM_NORESERVE
)) {
185 if (VM_ACCT(newsize
) > VM_ACCT(oldsize
))
186 return security_vm_enough_memory_mm(current
->mm
,
187 VM_ACCT(newsize
) - VM_ACCT(oldsize
));
188 else if (VM_ACCT(newsize
) < VM_ACCT(oldsize
))
189 vm_unacct_memory(VM_ACCT(oldsize
) - VM_ACCT(newsize
));
195 * ... whereas tmpfs objects are accounted incrementally as
196 * pages are allocated, in order to allow large sparse files.
197 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
198 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
200 static inline int shmem_acct_block(unsigned long flags
, long pages
)
202 if (!(flags
& VM_NORESERVE
))
205 return security_vm_enough_memory_mm(current
->mm
,
206 pages
* VM_ACCT(PAGE_SIZE
));
209 static inline void shmem_unacct_blocks(unsigned long flags
, long pages
)
211 if (flags
& VM_NORESERVE
)
212 vm_unacct_memory(pages
* VM_ACCT(PAGE_SIZE
));
215 static inline bool shmem_inode_acct_block(struct inode
*inode
, long pages
)
217 struct shmem_inode_info
*info
= SHMEM_I(inode
);
218 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
220 if (shmem_acct_block(info
->flags
, pages
))
223 if (sbinfo
->max_blocks
) {
224 if (percpu_counter_compare(&sbinfo
->used_blocks
,
225 sbinfo
->max_blocks
- pages
) > 0)
227 percpu_counter_add(&sbinfo
->used_blocks
, pages
);
233 shmem_unacct_blocks(info
->flags
, pages
);
237 static inline void shmem_inode_unacct_blocks(struct inode
*inode
, long pages
)
239 struct shmem_inode_info
*info
= SHMEM_I(inode
);
240 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
242 if (sbinfo
->max_blocks
)
243 percpu_counter_sub(&sbinfo
->used_blocks
, pages
);
244 shmem_unacct_blocks(info
->flags
, pages
);
247 static const struct super_operations shmem_ops
;
248 static const struct address_space_operations shmem_aops
;
249 static const struct file_operations shmem_file_operations
;
250 static const struct inode_operations shmem_inode_operations
;
251 static const struct inode_operations shmem_dir_inode_operations
;
252 static const struct inode_operations shmem_special_inode_operations
;
253 static const struct vm_operations_struct shmem_vm_ops
;
254 static struct file_system_type shmem_fs_type
;
256 bool vma_is_shmem(struct vm_area_struct
*vma
)
258 return vma
->vm_ops
== &shmem_vm_ops
;
261 static LIST_HEAD(shmem_swaplist
);
262 static DEFINE_MUTEX(shmem_swaplist_mutex
);
264 static int shmem_reserve_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 if (!sbinfo
->free_inodes
) {
270 spin_unlock(&sbinfo
->stat_lock
);
273 sbinfo
->free_inodes
--;
274 spin_unlock(&sbinfo
->stat_lock
);
279 static void shmem_free_inode(struct super_block
*sb
)
281 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
282 if (sbinfo
->max_inodes
) {
283 spin_lock(&sbinfo
->stat_lock
);
284 sbinfo
->free_inodes
++;
285 spin_unlock(&sbinfo
->stat_lock
);
290 * shmem_recalc_inode - recalculate the block usage of an inode
291 * @inode: inode to recalc
293 * We have to calculate the free blocks since the mm can drop
294 * undirtied hole pages behind our back.
296 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
297 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
299 * It has to be called with the spinlock held.
301 static void shmem_recalc_inode(struct inode
*inode
)
303 struct shmem_inode_info
*info
= SHMEM_I(inode
);
306 freed
= info
->alloced
- info
->swapped
- inode
->i_mapping
->nrpages
;
308 info
->alloced
-= freed
;
309 inode
->i_blocks
-= freed
* BLOCKS_PER_PAGE
;
310 shmem_inode_unacct_blocks(inode
, freed
);
314 bool shmem_charge(struct inode
*inode
, long pages
)
316 struct shmem_inode_info
*info
= SHMEM_I(inode
);
319 if (!shmem_inode_acct_block(inode
, pages
))
322 /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
323 inode
->i_mapping
->nrpages
+= pages
;
325 spin_lock_irqsave(&info
->lock
, flags
);
326 info
->alloced
+= pages
;
327 inode
->i_blocks
+= pages
* BLOCKS_PER_PAGE
;
328 shmem_recalc_inode(inode
);
329 spin_unlock_irqrestore(&info
->lock
, flags
);
334 void shmem_uncharge(struct inode
*inode
, long pages
)
336 struct shmem_inode_info
*info
= SHMEM_I(inode
);
339 /* nrpages adjustment done by __delete_from_page_cache() or caller */
341 spin_lock_irqsave(&info
->lock
, flags
);
342 info
->alloced
-= pages
;
343 inode
->i_blocks
-= pages
* BLOCKS_PER_PAGE
;
344 shmem_recalc_inode(inode
);
345 spin_unlock_irqrestore(&info
->lock
, flags
);
347 shmem_inode_unacct_blocks(inode
, pages
);
351 * Replace item expected in xarray by a new item, while holding xa_lock.
353 static int shmem_replace_entry(struct address_space
*mapping
,
354 pgoff_t index
, void *expected
, void *replacement
)
356 XA_STATE(xas
, &mapping
->i_pages
, index
);
359 VM_BUG_ON(!expected
);
360 VM_BUG_ON(!replacement
);
361 item
= xas_load(&xas
);
362 if (item
!= expected
)
364 xas_store(&xas
, replacement
);
369 * Sometimes, before we decide whether to proceed or to fail, we must check
370 * that an entry was not already brought back from swap by a racing thread.
372 * Checking page is not enough: by the time a SwapCache page is locked, it
373 * might be reused, and again be SwapCache, using the same swap as before.
375 static bool shmem_confirm_swap(struct address_space
*mapping
,
376 pgoff_t index
, swp_entry_t swap
)
378 return xa_load(&mapping
->i_pages
, index
) == swp_to_radix_entry(swap
);
382 * Definitions for "huge tmpfs": tmpfs mounted with the huge= option
385 * disables huge pages for the mount;
387 * enables huge pages for the mount;
388 * SHMEM_HUGE_WITHIN_SIZE:
389 * only allocate huge pages if the page will be fully within i_size,
390 * also respect fadvise()/madvise() hints;
392 * only allocate huge pages if requested with fadvise()/madvise();
395 #define SHMEM_HUGE_NEVER 0
396 #define SHMEM_HUGE_ALWAYS 1
397 #define SHMEM_HUGE_WITHIN_SIZE 2
398 #define SHMEM_HUGE_ADVISE 3
402 * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
405 * disables huge on shm_mnt and all mounts, for emergency use;
407 * enables huge on shm_mnt and all mounts, w/o needing option, for testing;
410 #define SHMEM_HUGE_DENY (-1)
411 #define SHMEM_HUGE_FORCE (-2)
413 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
414 /* ifdef here to avoid bloating shmem.o when not necessary */
416 static int shmem_huge __read_mostly
;
418 #if defined(CONFIG_SYSFS)
419 static int shmem_parse_huge(const char *str
)
421 if (!strcmp(str
, "never"))
422 return SHMEM_HUGE_NEVER
;
423 if (!strcmp(str
, "always"))
424 return SHMEM_HUGE_ALWAYS
;
425 if (!strcmp(str
, "within_size"))
426 return SHMEM_HUGE_WITHIN_SIZE
;
427 if (!strcmp(str
, "advise"))
428 return SHMEM_HUGE_ADVISE
;
429 if (!strcmp(str
, "deny"))
430 return SHMEM_HUGE_DENY
;
431 if (!strcmp(str
, "force"))
432 return SHMEM_HUGE_FORCE
;
437 #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
438 static const char *shmem_format_huge(int huge
)
441 case SHMEM_HUGE_NEVER
:
443 case SHMEM_HUGE_ALWAYS
:
445 case SHMEM_HUGE_WITHIN_SIZE
:
446 return "within_size";
447 case SHMEM_HUGE_ADVISE
:
449 case SHMEM_HUGE_DENY
:
451 case SHMEM_HUGE_FORCE
:
460 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
461 struct shrink_control
*sc
, unsigned long nr_to_split
)
463 LIST_HEAD(list
), *pos
, *next
;
464 LIST_HEAD(to_remove
);
466 struct shmem_inode_info
*info
;
468 unsigned long batch
= sc
? sc
->nr_to_scan
: 128;
469 int removed
= 0, split
= 0;
471 if (list_empty(&sbinfo
->shrinklist
))
474 spin_lock(&sbinfo
->shrinklist_lock
);
475 list_for_each_safe(pos
, next
, &sbinfo
->shrinklist
) {
476 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
479 inode
= igrab(&info
->vfs_inode
);
481 /* inode is about to be evicted */
483 list_del_init(&info
->shrinklist
);
488 /* Check if there's anything to gain */
489 if (round_up(inode
->i_size
, PAGE_SIZE
) ==
490 round_up(inode
->i_size
, HPAGE_PMD_SIZE
)) {
491 list_move(&info
->shrinklist
, &to_remove
);
496 list_move(&info
->shrinklist
, &list
);
501 spin_unlock(&sbinfo
->shrinklist_lock
);
503 list_for_each_safe(pos
, next
, &to_remove
) {
504 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
505 inode
= &info
->vfs_inode
;
506 list_del_init(&info
->shrinklist
);
510 list_for_each_safe(pos
, next
, &list
) {
513 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
514 inode
= &info
->vfs_inode
;
516 if (nr_to_split
&& split
>= nr_to_split
)
519 page
= find_get_page(inode
->i_mapping
,
520 (inode
->i_size
& HPAGE_PMD_MASK
) >> PAGE_SHIFT
);
524 /* No huge page at the end of the file: nothing to split */
525 if (!PageTransHuge(page
)) {
531 * Leave the inode on the list if we failed to lock
532 * the page at this time.
534 * Waiting for the lock may lead to deadlock in the
537 if (!trylock_page(page
)) {
542 ret
= split_huge_page(page
);
546 /* If split failed leave the inode on the list */
552 list_del_init(&info
->shrinklist
);
558 spin_lock(&sbinfo
->shrinklist_lock
);
559 list_splice_tail(&list
, &sbinfo
->shrinklist
);
560 sbinfo
->shrinklist_len
-= removed
;
561 spin_unlock(&sbinfo
->shrinklist_lock
);
566 static long shmem_unused_huge_scan(struct super_block
*sb
,
567 struct shrink_control
*sc
)
569 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
571 if (!READ_ONCE(sbinfo
->shrinklist_len
))
574 return shmem_unused_huge_shrink(sbinfo
, sc
, 0);
577 static long shmem_unused_huge_count(struct super_block
*sb
,
578 struct shrink_control
*sc
)
580 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
581 return READ_ONCE(sbinfo
->shrinklist_len
);
583 #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
585 #define shmem_huge SHMEM_HUGE_DENY
587 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
588 struct shrink_control
*sc
, unsigned long nr_to_split
)
592 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
594 static inline bool is_huge_enabled(struct shmem_sb_info
*sbinfo
)
596 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
597 (shmem_huge
== SHMEM_HUGE_FORCE
|| sbinfo
->huge
) &&
598 shmem_huge
!= SHMEM_HUGE_DENY
)
604 * Like add_to_page_cache_locked, but error if expected item has gone.
606 static int shmem_add_to_page_cache(struct page
*page
,
607 struct address_space
*mapping
,
608 pgoff_t index
, void *expected
, gfp_t gfp
)
610 XA_STATE_ORDER(xas
, &mapping
->i_pages
, index
, compound_order(page
));
612 unsigned long nr
= compound_nr(page
);
614 VM_BUG_ON_PAGE(PageTail(page
), page
);
615 VM_BUG_ON_PAGE(index
!= round_down(index
, nr
), page
);
616 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
617 VM_BUG_ON_PAGE(!PageSwapBacked(page
), page
);
618 VM_BUG_ON(expected
&& PageTransHuge(page
));
620 page_ref_add(page
, nr
);
621 page
->mapping
= mapping
;
627 entry
= xas_find_conflict(&xas
);
628 if (entry
!= expected
)
629 xas_set_err(&xas
, -EEXIST
);
630 xas_create_range(&xas
);
634 xas_store(&xas
, page
);
639 if (PageTransHuge(page
)) {
640 count_vm_event(THP_FILE_ALLOC
);
641 __inc_node_page_state(page
, NR_SHMEM_THPS
);
643 mapping
->nrpages
+= nr
;
644 __mod_node_page_state(page_pgdat(page
), NR_FILE_PAGES
, nr
);
645 __mod_node_page_state(page_pgdat(page
), NR_SHMEM
, nr
);
647 xas_unlock_irq(&xas
);
648 } while (xas_nomem(&xas
, gfp
));
650 if (xas_error(&xas
)) {
651 page
->mapping
= NULL
;
652 page_ref_sub(page
, nr
);
653 return xas_error(&xas
);
660 * Like delete_from_page_cache, but substitutes swap for page.
662 static void shmem_delete_from_page_cache(struct page
*page
, void *radswap
)
664 struct address_space
*mapping
= page
->mapping
;
667 VM_BUG_ON_PAGE(PageCompound(page
), page
);
669 xa_lock_irq(&mapping
->i_pages
);
670 error
= shmem_replace_entry(mapping
, page
->index
, page
, radswap
);
671 page
->mapping
= NULL
;
673 __dec_node_page_state(page
, NR_FILE_PAGES
);
674 __dec_node_page_state(page
, NR_SHMEM
);
675 xa_unlock_irq(&mapping
->i_pages
);
681 * Remove swap entry from page cache, free the swap and its page cache.
683 static int shmem_free_swap(struct address_space
*mapping
,
684 pgoff_t index
, void *radswap
)
688 old
= xa_cmpxchg_irq(&mapping
->i_pages
, index
, radswap
, NULL
, 0);
691 free_swap_and_cache(radix_to_swp_entry(radswap
));
696 * Determine (in bytes) how many of the shmem object's pages mapped by the
697 * given offsets are swapped out.
699 * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
700 * as long as the inode doesn't go away and racy results are not a problem.
702 unsigned long shmem_partial_swap_usage(struct address_space
*mapping
,
703 pgoff_t start
, pgoff_t end
)
705 XA_STATE(xas
, &mapping
->i_pages
, start
);
707 unsigned long swapped
= 0;
710 xas_for_each(&xas
, page
, end
- 1) {
711 if (xas_retry(&xas
, page
))
713 if (xa_is_value(page
))
716 if (need_resched()) {
724 return swapped
<< PAGE_SHIFT
;
728 * Determine (in bytes) how many of the shmem object's pages mapped by the
729 * given vma is swapped out.
731 * This is safe to call without i_mutex or the i_pages lock thanks to RCU,
732 * as long as the inode doesn't go away and racy results are not a problem.
734 unsigned long shmem_swap_usage(struct vm_area_struct
*vma
)
736 struct inode
*inode
= file_inode(vma
->vm_file
);
737 struct shmem_inode_info
*info
= SHMEM_I(inode
);
738 struct address_space
*mapping
= inode
->i_mapping
;
739 unsigned long swapped
;
741 /* Be careful as we don't hold info->lock */
742 swapped
= READ_ONCE(info
->swapped
);
745 * The easier cases are when the shmem object has nothing in swap, or
746 * the vma maps it whole. Then we can simply use the stats that we
752 if (!vma
->vm_pgoff
&& vma
->vm_end
- vma
->vm_start
>= inode
->i_size
)
753 return swapped
<< PAGE_SHIFT
;
755 /* Here comes the more involved part */
756 return shmem_partial_swap_usage(mapping
,
757 linear_page_index(vma
, vma
->vm_start
),
758 linear_page_index(vma
, vma
->vm_end
));
762 * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
764 void shmem_unlock_mapping(struct address_space
*mapping
)
767 pgoff_t indices
[PAGEVEC_SIZE
];
772 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
774 while (!mapping_unevictable(mapping
)) {
776 * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
777 * has finished, if it hits a row of PAGEVEC_SIZE swap entries.
779 pvec
.nr
= find_get_entries(mapping
, index
,
780 PAGEVEC_SIZE
, pvec
.pages
, indices
);
783 index
= indices
[pvec
.nr
- 1] + 1;
784 pagevec_remove_exceptionals(&pvec
);
785 check_move_unevictable_pages(&pvec
);
786 pagevec_release(&pvec
);
792 * Remove range of pages and swap entries from page cache, and free them.
793 * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
795 static void shmem_undo_range(struct inode
*inode
, loff_t lstart
, loff_t lend
,
798 struct address_space
*mapping
= inode
->i_mapping
;
799 struct shmem_inode_info
*info
= SHMEM_I(inode
);
800 pgoff_t start
= (lstart
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
801 pgoff_t end
= (lend
+ 1) >> PAGE_SHIFT
;
802 unsigned int partial_start
= lstart
& (PAGE_SIZE
- 1);
803 unsigned int partial_end
= (lend
+ 1) & (PAGE_SIZE
- 1);
805 pgoff_t indices
[PAGEVEC_SIZE
];
806 long nr_swaps_freed
= 0;
811 end
= -1; /* unsigned, so actually very big */
815 while (index
< end
) {
816 pvec
.nr
= find_get_entries(mapping
, index
,
817 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
818 pvec
.pages
, indices
);
821 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
822 struct page
*page
= pvec
.pages
[i
];
828 if (xa_is_value(page
)) {
831 nr_swaps_freed
+= !shmem_free_swap(mapping
,
836 VM_BUG_ON_PAGE(page_to_pgoff(page
) != index
, page
);
838 if (!trylock_page(page
))
841 if (PageTransTail(page
)) {
842 /* Middle of THP: zero out the page */
843 clear_highpage(page
);
846 } else if (PageTransHuge(page
)) {
847 if (index
== round_down(end
, HPAGE_PMD_NR
)) {
849 * Range ends in the middle of THP:
852 clear_highpage(page
);
856 index
+= HPAGE_PMD_NR
- 1;
857 i
+= HPAGE_PMD_NR
- 1;
860 if (!unfalloc
|| !PageUptodate(page
)) {
861 VM_BUG_ON_PAGE(PageTail(page
), page
);
862 if (page_mapping(page
) == mapping
) {
863 VM_BUG_ON_PAGE(PageWriteback(page
), page
);
864 truncate_inode_page(mapping
, page
);
869 pagevec_remove_exceptionals(&pvec
);
870 pagevec_release(&pvec
);
876 struct page
*page
= NULL
;
877 shmem_getpage(inode
, start
- 1, &page
, SGP_READ
);
879 unsigned int top
= PAGE_SIZE
;
884 zero_user_segment(page
, partial_start
, top
);
885 set_page_dirty(page
);
891 struct page
*page
= NULL
;
892 shmem_getpage(inode
, end
, &page
, SGP_READ
);
894 zero_user_segment(page
, 0, partial_end
);
895 set_page_dirty(page
);
904 while (index
< end
) {
907 pvec
.nr
= find_get_entries(mapping
, index
,
908 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
909 pvec
.pages
, indices
);
911 /* If all gone or hole-punch or unfalloc, we're done */
912 if (index
== start
|| end
!= -1)
914 /* But if truncating, restart to make sure all gone */
918 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
919 struct page
*page
= pvec
.pages
[i
];
925 if (xa_is_value(page
)) {
928 if (shmem_free_swap(mapping
, index
, page
)) {
929 /* Swap was replaced by page: retry */
939 if (PageTransTail(page
)) {
940 /* Middle of THP: zero out the page */
941 clear_highpage(page
);
944 * Partial thp truncate due 'start' in middle
945 * of THP: don't need to look on these pages
946 * again on !pvec.nr restart.
948 if (index
!= round_down(end
, HPAGE_PMD_NR
))
951 } else if (PageTransHuge(page
)) {
952 if (index
== round_down(end
, HPAGE_PMD_NR
)) {
954 * Range ends in the middle of THP:
957 clear_highpage(page
);
961 index
+= HPAGE_PMD_NR
- 1;
962 i
+= HPAGE_PMD_NR
- 1;
965 if (!unfalloc
|| !PageUptodate(page
)) {
966 VM_BUG_ON_PAGE(PageTail(page
), page
);
967 if (page_mapping(page
) == mapping
) {
968 VM_BUG_ON_PAGE(PageWriteback(page
), page
);
969 truncate_inode_page(mapping
, page
);
971 /* Page was replaced by swap: retry */
979 pagevec_remove_exceptionals(&pvec
);
980 pagevec_release(&pvec
);
984 spin_lock_irq(&info
->lock
);
985 info
->swapped
-= nr_swaps_freed
;
986 shmem_recalc_inode(inode
);
987 spin_unlock_irq(&info
->lock
);
990 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
992 shmem_undo_range(inode
, lstart
, lend
, false);
993 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
995 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
997 static int shmem_getattr(const struct path
*path
, struct kstat
*stat
,
998 u32 request_mask
, unsigned int query_flags
)
1000 struct inode
*inode
= path
->dentry
->d_inode
;
1001 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1002 struct shmem_sb_info
*sb_info
= SHMEM_SB(inode
->i_sb
);
1004 if (info
->alloced
- info
->swapped
!= inode
->i_mapping
->nrpages
) {
1005 spin_lock_irq(&info
->lock
);
1006 shmem_recalc_inode(inode
);
1007 spin_unlock_irq(&info
->lock
);
1009 generic_fillattr(inode
, stat
);
1011 if (is_huge_enabled(sb_info
))
1012 stat
->blksize
= HPAGE_PMD_SIZE
;
1017 static int shmem_setattr(struct dentry
*dentry
, struct iattr
*attr
)
1019 struct inode
*inode
= d_inode(dentry
);
1020 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1021 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
1024 error
= setattr_prepare(dentry
, attr
);
1028 if (S_ISREG(inode
->i_mode
) && (attr
->ia_valid
& ATTR_SIZE
)) {
1029 loff_t oldsize
= inode
->i_size
;
1030 loff_t newsize
= attr
->ia_size
;
1032 /* protected by i_mutex */
1033 if ((newsize
< oldsize
&& (info
->seals
& F_SEAL_SHRINK
)) ||
1034 (newsize
> oldsize
&& (info
->seals
& F_SEAL_GROW
)))
1037 if (newsize
!= oldsize
) {
1038 error
= shmem_reacct_size(SHMEM_I(inode
)->flags
,
1042 i_size_write(inode
, newsize
);
1043 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
1045 if (newsize
<= oldsize
) {
1046 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
1047 if (oldsize
> holebegin
)
1048 unmap_mapping_range(inode
->i_mapping
,
1051 shmem_truncate_range(inode
,
1052 newsize
, (loff_t
)-1);
1053 /* unmap again to remove racily COWed private pages */
1054 if (oldsize
> holebegin
)
1055 unmap_mapping_range(inode
->i_mapping
,
1059 * Part of the huge page can be beyond i_size: subject
1060 * to shrink under memory pressure.
1062 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
)) {
1063 spin_lock(&sbinfo
->shrinklist_lock
);
1065 * _careful to defend against unlocked access to
1066 * ->shrink_list in shmem_unused_huge_shrink()
1068 if (list_empty_careful(&info
->shrinklist
)) {
1069 list_add_tail(&info
->shrinklist
,
1070 &sbinfo
->shrinklist
);
1071 sbinfo
->shrinklist_len
++;
1073 spin_unlock(&sbinfo
->shrinklist_lock
);
1078 setattr_copy(inode
, attr
);
1079 if (attr
->ia_valid
& ATTR_MODE
)
1080 error
= posix_acl_chmod(inode
, inode
->i_mode
);
1084 static void shmem_evict_inode(struct inode
*inode
)
1086 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1087 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
1089 if (inode
->i_mapping
->a_ops
== &shmem_aops
) {
1090 shmem_unacct_size(info
->flags
, inode
->i_size
);
1092 shmem_truncate_range(inode
, 0, (loff_t
)-1);
1093 if (!list_empty(&info
->shrinklist
)) {
1094 spin_lock(&sbinfo
->shrinklist_lock
);
1095 if (!list_empty(&info
->shrinklist
)) {
1096 list_del_init(&info
->shrinklist
);
1097 sbinfo
->shrinklist_len
--;
1099 spin_unlock(&sbinfo
->shrinklist_lock
);
1101 while (!list_empty(&info
->swaplist
)) {
1102 /* Wait while shmem_unuse() is scanning this inode... */
1103 wait_var_event(&info
->stop_eviction
,
1104 !atomic_read(&info
->stop_eviction
));
1105 mutex_lock(&shmem_swaplist_mutex
);
1106 /* ...but beware of the race if we peeked too early */
1107 if (!atomic_read(&info
->stop_eviction
))
1108 list_del_init(&info
->swaplist
);
1109 mutex_unlock(&shmem_swaplist_mutex
);
1113 simple_xattrs_free(&info
->xattrs
);
1114 WARN_ON(inode
->i_blocks
);
1115 shmem_free_inode(inode
->i_sb
);
1119 extern struct swap_info_struct
*swap_info
[];
1121 static int shmem_find_swap_entries(struct address_space
*mapping
,
1122 pgoff_t start
, unsigned int nr_entries
,
1123 struct page
**entries
, pgoff_t
*indices
,
1124 unsigned int type
, bool frontswap
)
1126 XA_STATE(xas
, &mapping
->i_pages
, start
);
1129 unsigned int ret
= 0;
1135 xas_for_each(&xas
, page
, ULONG_MAX
) {
1136 if (xas_retry(&xas
, page
))
1139 if (!xa_is_value(page
))
1142 entry
= radix_to_swp_entry(page
);
1143 if (swp_type(entry
) != type
)
1146 !frontswap_test(swap_info
[type
], swp_offset(entry
)))
1149 indices
[ret
] = xas
.xa_index
;
1150 entries
[ret
] = page
;
1152 if (need_resched()) {
1156 if (++ret
== nr_entries
)
1165 * Move the swapped pages for an inode to page cache. Returns the count
1166 * of pages swapped in, or the error in case of failure.
1168 static int shmem_unuse_swap_entries(struct inode
*inode
, struct pagevec pvec
,
1174 struct address_space
*mapping
= inode
->i_mapping
;
1176 for (i
= 0; i
< pvec
.nr
; i
++) {
1177 struct page
*page
= pvec
.pages
[i
];
1179 if (!xa_is_value(page
))
1181 error
= shmem_swapin_page(inode
, indices
[i
],
1183 mapping_gfp_mask(mapping
),
1190 if (error
== -ENOMEM
)
1194 return error
? error
: ret
;
1198 * If swap found in inode, free it and move page from swapcache to filecache.
1200 static int shmem_unuse_inode(struct inode
*inode
, unsigned int type
,
1201 bool frontswap
, unsigned long *fs_pages_to_unuse
)
1203 struct address_space
*mapping
= inode
->i_mapping
;
1205 struct pagevec pvec
;
1206 pgoff_t indices
[PAGEVEC_SIZE
];
1207 bool frontswap_partial
= (frontswap
&& *fs_pages_to_unuse
> 0);
1210 pagevec_init(&pvec
);
1212 unsigned int nr_entries
= PAGEVEC_SIZE
;
1214 if (frontswap_partial
&& *fs_pages_to_unuse
< PAGEVEC_SIZE
)
1215 nr_entries
= *fs_pages_to_unuse
;
1217 pvec
.nr
= shmem_find_swap_entries(mapping
, start
, nr_entries
,
1218 pvec
.pages
, indices
,
1225 ret
= shmem_unuse_swap_entries(inode
, pvec
, indices
);
1229 if (frontswap_partial
) {
1230 *fs_pages_to_unuse
-= ret
;
1231 if (*fs_pages_to_unuse
== 0) {
1232 ret
= FRONTSWAP_PAGES_UNUSED
;
1237 start
= indices
[pvec
.nr
- 1];
1244 * Read all the shared memory data that resides in the swap
1245 * device 'type' back into memory, so the swap device can be
1248 int shmem_unuse(unsigned int type
, bool frontswap
,
1249 unsigned long *fs_pages_to_unuse
)
1251 struct shmem_inode_info
*info
, *next
;
1254 if (list_empty(&shmem_swaplist
))
1257 mutex_lock(&shmem_swaplist_mutex
);
1258 list_for_each_entry_safe(info
, next
, &shmem_swaplist
, swaplist
) {
1259 if (!info
->swapped
) {
1260 list_del_init(&info
->swaplist
);
1264 * Drop the swaplist mutex while searching the inode for swap;
1265 * but before doing so, make sure shmem_evict_inode() will not
1266 * remove placeholder inode from swaplist, nor let it be freed
1267 * (igrab() would protect from unlink, but not from unmount).
1269 atomic_inc(&info
->stop_eviction
);
1270 mutex_unlock(&shmem_swaplist_mutex
);
1272 error
= shmem_unuse_inode(&info
->vfs_inode
, type
, frontswap
,
1276 mutex_lock(&shmem_swaplist_mutex
);
1277 next
= list_next_entry(info
, swaplist
);
1279 list_del_init(&info
->swaplist
);
1280 if (atomic_dec_and_test(&info
->stop_eviction
))
1281 wake_up_var(&info
->stop_eviction
);
1285 mutex_unlock(&shmem_swaplist_mutex
);
1291 * Move the page from the page cache to the swap cache.
1293 static int shmem_writepage(struct page
*page
, struct writeback_control
*wbc
)
1295 struct shmem_inode_info
*info
;
1296 struct address_space
*mapping
;
1297 struct inode
*inode
;
1301 VM_BUG_ON_PAGE(PageCompound(page
), page
);
1302 BUG_ON(!PageLocked(page
));
1303 mapping
= page
->mapping
;
1304 index
= page
->index
;
1305 inode
= mapping
->host
;
1306 info
= SHMEM_I(inode
);
1307 if (info
->flags
& VM_LOCKED
)
1309 if (!total_swap_pages
)
1313 * Our capabilities prevent regular writeback or sync from ever calling
1314 * shmem_writepage; but a stacking filesystem might use ->writepage of
1315 * its underlying filesystem, in which case tmpfs should write out to
1316 * swap only in response to memory pressure, and not for the writeback
1319 if (!wbc
->for_reclaim
) {
1320 WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
1325 * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
1326 * value into swapfile.c, the only way we can correctly account for a
1327 * fallocated page arriving here is now to initialize it and write it.
1329 * That's okay for a page already fallocated earlier, but if we have
1330 * not yet completed the fallocation, then (a) we want to keep track
1331 * of this page in case we have to undo it, and (b) it may not be a
1332 * good idea to continue anyway, once we're pushing into swap. So
1333 * reactivate the page, and let shmem_fallocate() quit when too many.
1335 if (!PageUptodate(page
)) {
1336 if (inode
->i_private
) {
1337 struct shmem_falloc
*shmem_falloc
;
1338 spin_lock(&inode
->i_lock
);
1339 shmem_falloc
= inode
->i_private
;
1341 !shmem_falloc
->waitq
&&
1342 index
>= shmem_falloc
->start
&&
1343 index
< shmem_falloc
->next
)
1344 shmem_falloc
->nr_unswapped
++;
1346 shmem_falloc
= NULL
;
1347 spin_unlock(&inode
->i_lock
);
1351 clear_highpage(page
);
1352 flush_dcache_page(page
);
1353 SetPageUptodate(page
);
1356 swap
= get_swap_page(page
);
1361 * Add inode to shmem_unuse()'s list of swapped-out inodes,
1362 * if it's not already there. Do it now before the page is
1363 * moved to swap cache, when its pagelock no longer protects
1364 * the inode from eviction. But don't unlock the mutex until
1365 * we've incremented swapped, because shmem_unuse_inode() will
1366 * prune a !swapped inode from the swaplist under this mutex.
1368 mutex_lock(&shmem_swaplist_mutex
);
1369 if (list_empty(&info
->swaplist
))
1370 list_add(&info
->swaplist
, &shmem_swaplist
);
1372 if (add_to_swap_cache(page
, swap
,
1373 __GFP_HIGH
| __GFP_NOMEMALLOC
| __GFP_NOWARN
) == 0) {
1374 spin_lock_irq(&info
->lock
);
1375 shmem_recalc_inode(inode
);
1377 spin_unlock_irq(&info
->lock
);
1379 swap_shmem_alloc(swap
);
1380 shmem_delete_from_page_cache(page
, swp_to_radix_entry(swap
));
1382 mutex_unlock(&shmem_swaplist_mutex
);
1383 BUG_ON(page_mapped(page
));
1384 swap_writepage(page
, wbc
);
1388 mutex_unlock(&shmem_swaplist_mutex
);
1389 put_swap_page(page
, swap
);
1391 set_page_dirty(page
);
1392 if (wbc
->for_reclaim
)
1393 return AOP_WRITEPAGE_ACTIVATE
; /* Return with page locked */
1398 #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
1399 static void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1403 if (!mpol
|| mpol
->mode
== MPOL_DEFAULT
)
1404 return; /* show nothing */
1406 mpol_to_str(buffer
, sizeof(buffer
), mpol
);
1408 seq_printf(seq
, ",mpol=%s", buffer
);
1411 static struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1413 struct mempolicy
*mpol
= NULL
;
1415 spin_lock(&sbinfo
->stat_lock
); /* prevent replace/use races */
1416 mpol
= sbinfo
->mpol
;
1418 spin_unlock(&sbinfo
->stat_lock
);
1422 #else /* !CONFIG_NUMA || !CONFIG_TMPFS */
1423 static inline void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1426 static inline struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1430 #endif /* CONFIG_NUMA && CONFIG_TMPFS */
1432 #define vm_policy vm_private_data
1435 static void shmem_pseudo_vma_init(struct vm_area_struct
*vma
,
1436 struct shmem_inode_info
*info
, pgoff_t index
)
1438 /* Create a pseudo vma that just contains the policy */
1439 vma_init(vma
, NULL
);
1440 /* Bias interleave by inode number to distribute better across nodes */
1441 vma
->vm_pgoff
= index
+ info
->vfs_inode
.i_ino
;
1442 vma
->vm_policy
= mpol_shared_policy_lookup(&info
->policy
, index
);
1445 static void shmem_pseudo_vma_destroy(struct vm_area_struct
*vma
)
1447 /* Drop reference taken by mpol_shared_policy_lookup() */
1448 mpol_cond_put(vma
->vm_policy
);
1451 static struct page
*shmem_swapin(swp_entry_t swap
, gfp_t gfp
,
1452 struct shmem_inode_info
*info
, pgoff_t index
)
1454 struct vm_area_struct pvma
;
1456 struct vm_fault vmf
;
1458 shmem_pseudo_vma_init(&pvma
, info
, index
);
1461 page
= swap_cluster_readahead(swap
, gfp
, &vmf
);
1462 shmem_pseudo_vma_destroy(&pvma
);
1467 static struct page
*shmem_alloc_hugepage(gfp_t gfp
,
1468 struct shmem_inode_info
*info
, pgoff_t index
)
1470 struct vm_area_struct pvma
;
1471 struct address_space
*mapping
= info
->vfs_inode
.i_mapping
;
1475 hindex
= round_down(index
, HPAGE_PMD_NR
);
1476 if (xa_find(&mapping
->i_pages
, &hindex
, hindex
+ HPAGE_PMD_NR
- 1,
1480 shmem_pseudo_vma_init(&pvma
, info
, hindex
);
1481 page
= alloc_pages_vma(gfp
| __GFP_COMP
| __GFP_NORETRY
| __GFP_NOWARN
,
1482 HPAGE_PMD_ORDER
, &pvma
, 0, numa_node_id(), true);
1483 shmem_pseudo_vma_destroy(&pvma
);
1485 prep_transhuge_page(page
);
1487 count_vm_event(THP_FILE_FALLBACK
);
1491 static struct page
*shmem_alloc_page(gfp_t gfp
,
1492 struct shmem_inode_info
*info
, pgoff_t index
)
1494 struct vm_area_struct pvma
;
1497 shmem_pseudo_vma_init(&pvma
, info
, index
);
1498 page
= alloc_page_vma(gfp
, &pvma
, 0);
1499 shmem_pseudo_vma_destroy(&pvma
);
1504 static struct page
*shmem_alloc_and_acct_page(gfp_t gfp
,
1505 struct inode
*inode
,
1506 pgoff_t index
, bool huge
)
1508 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1513 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
))
1515 nr
= huge
? HPAGE_PMD_NR
: 1;
1517 if (!shmem_inode_acct_block(inode
, nr
))
1521 page
= shmem_alloc_hugepage(gfp
, info
, index
);
1523 page
= shmem_alloc_page(gfp
, info
, index
);
1525 __SetPageLocked(page
);
1526 __SetPageSwapBacked(page
);
1531 shmem_inode_unacct_blocks(inode
, nr
);
1533 return ERR_PTR(err
);
1537 * When a page is moved from swapcache to shmem filecache (either by the
1538 * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
1539 * shmem_unuse_inode()), it may have been read in earlier from swap, in
1540 * ignorance of the mapping it belongs to. If that mapping has special
1541 * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
1542 * we may need to copy to a suitable page before moving to filecache.
1544 * In a future release, this may well be extended to respect cpuset and
1545 * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
1546 * but for now it is a simple matter of zone.
1548 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
)
1550 return page_zonenum(page
) > gfp_zone(gfp
);
1553 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
1554 struct shmem_inode_info
*info
, pgoff_t index
)
1556 struct page
*oldpage
, *newpage
;
1557 struct address_space
*swap_mapping
;
1563 entry
.val
= page_private(oldpage
);
1564 swap_index
= swp_offset(entry
);
1565 swap_mapping
= page_mapping(oldpage
);
1568 * We have arrived here because our zones are constrained, so don't
1569 * limit chance of success by further cpuset and node constraints.
1571 gfp
&= ~GFP_CONSTRAINT_MASK
;
1572 newpage
= shmem_alloc_page(gfp
, info
, index
);
1577 copy_highpage(newpage
, oldpage
);
1578 flush_dcache_page(newpage
);
1580 __SetPageLocked(newpage
);
1581 __SetPageSwapBacked(newpage
);
1582 SetPageUptodate(newpage
);
1583 set_page_private(newpage
, entry
.val
);
1584 SetPageSwapCache(newpage
);
1587 * Our caller will very soon move newpage out of swapcache, but it's
1588 * a nice clean interface for us to replace oldpage by newpage there.
1590 xa_lock_irq(&swap_mapping
->i_pages
);
1591 error
= shmem_replace_entry(swap_mapping
, swap_index
, oldpage
, newpage
);
1593 __inc_node_page_state(newpage
, NR_FILE_PAGES
);
1594 __dec_node_page_state(oldpage
, NR_FILE_PAGES
);
1596 xa_unlock_irq(&swap_mapping
->i_pages
);
1598 if (unlikely(error
)) {
1600 * Is this possible? I think not, now that our callers check
1601 * both PageSwapCache and page_private after getting page lock;
1602 * but be defensive. Reverse old to newpage for clear and free.
1606 mem_cgroup_migrate(oldpage
, newpage
);
1607 lru_cache_add_anon(newpage
);
1611 ClearPageSwapCache(oldpage
);
1612 set_page_private(oldpage
, 0);
1614 unlock_page(oldpage
);
1621 * Swap in the page pointed to by *pagep.
1622 * Caller has to make sure that *pagep contains a valid swapped page.
1623 * Returns 0 and the page in pagep if success. On failure, returns the
1624 * the error code and NULL in *pagep.
1626 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
1627 struct page
**pagep
, enum sgp_type sgp
,
1628 gfp_t gfp
, struct vm_area_struct
*vma
,
1629 vm_fault_t
*fault_type
)
1631 struct address_space
*mapping
= inode
->i_mapping
;
1632 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1633 struct mm_struct
*charge_mm
= vma
? vma
->vm_mm
: current
->mm
;
1634 struct mem_cgroup
*memcg
;
1639 VM_BUG_ON(!*pagep
|| !xa_is_value(*pagep
));
1640 swap
= radix_to_swp_entry(*pagep
);
1643 /* Look it up and read it in.. */
1644 page
= lookup_swap_cache(swap
, NULL
, 0);
1646 /* Or update major stats only when swapin succeeds?? */
1648 *fault_type
|= VM_FAULT_MAJOR
;
1649 count_vm_event(PGMAJFAULT
);
1650 count_memcg_event_mm(charge_mm
, PGMAJFAULT
);
1652 /* Here we actually start the io */
1653 page
= shmem_swapin(swap
, gfp
, info
, index
);
1660 /* We have to do this with page locked to prevent races */
1662 if (!PageSwapCache(page
) || page_private(page
) != swap
.val
||
1663 !shmem_confirm_swap(mapping
, index
, swap
)) {
1667 if (!PageUptodate(page
)) {
1671 wait_on_page_writeback(page
);
1673 if (shmem_should_replace_page(page
, gfp
)) {
1674 error
= shmem_replace_page(&page
, gfp
, info
, index
);
1679 error
= mem_cgroup_try_charge_delay(page
, charge_mm
, gfp
, &memcg
,
1682 error
= shmem_add_to_page_cache(page
, mapping
, index
,
1683 swp_to_radix_entry(swap
), gfp
);
1685 * We already confirmed swap under page lock, and make
1686 * no memory allocation here, so usually no possibility
1687 * of error; but free_swap_and_cache() only trylocks a
1688 * page, so it is just possible that the entry has been
1689 * truncated or holepunched since swap was confirmed.
1690 * shmem_undo_range() will have done some of the
1691 * unaccounting, now delete_from_swap_cache() will do
1695 mem_cgroup_cancel_charge(page
, memcg
, false);
1696 delete_from_swap_cache(page
);
1702 mem_cgroup_commit_charge(page
, memcg
, true, false);
1704 spin_lock_irq(&info
->lock
);
1706 shmem_recalc_inode(inode
);
1707 spin_unlock_irq(&info
->lock
);
1709 if (sgp
== SGP_WRITE
)
1710 mark_page_accessed(page
);
1712 delete_from_swap_cache(page
);
1713 set_page_dirty(page
);
1719 if (!shmem_confirm_swap(mapping
, index
, swap
))
1731 * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
1733 * If we allocate a new one we do not mark it dirty. That's up to the
1734 * vm. If we swap it in we mark it dirty since we also free the swap
1735 * entry since a page cannot live in both the swap and page cache.
1737 * vmf and fault_type are only supplied by shmem_fault:
1738 * otherwise they are NULL.
1740 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
1741 struct page
**pagep
, enum sgp_type sgp
, gfp_t gfp
,
1742 struct vm_area_struct
*vma
, struct vm_fault
*vmf
,
1743 vm_fault_t
*fault_type
)
1745 struct address_space
*mapping
= inode
->i_mapping
;
1746 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1747 struct shmem_sb_info
*sbinfo
;
1748 struct mm_struct
*charge_mm
;
1749 struct mem_cgroup
*memcg
;
1751 enum sgp_type sgp_huge
= sgp
;
1752 pgoff_t hindex
= index
;
1757 if (index
> (MAX_LFS_FILESIZE
>> PAGE_SHIFT
))
1759 if (sgp
== SGP_NOHUGE
|| sgp
== SGP_HUGE
)
1762 if (sgp
<= SGP_CACHE
&&
1763 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1767 sbinfo
= SHMEM_SB(inode
->i_sb
);
1768 charge_mm
= vma
? vma
->vm_mm
: current
->mm
;
1770 page
= find_lock_entry(mapping
, index
);
1771 if (xa_is_value(page
)) {
1772 error
= shmem_swapin_page(inode
, index
, &page
,
1773 sgp
, gfp
, vma
, fault_type
);
1774 if (error
== -EEXIST
)
1781 if (page
&& sgp
== SGP_WRITE
)
1782 mark_page_accessed(page
);
1784 /* fallocated page? */
1785 if (page
&& !PageUptodate(page
)) {
1786 if (sgp
!= SGP_READ
)
1792 if (page
|| sgp
== SGP_READ
) {
1798 * Fast cache lookup did not find it:
1799 * bring it back from swap or allocate.
1802 if (vma
&& userfaultfd_missing(vma
)) {
1803 *fault_type
= handle_userfault(vmf
, VM_UFFD_MISSING
);
1807 /* shmem_symlink() */
1808 if (mapping
->a_ops
!= &shmem_aops
)
1810 if (shmem_huge
== SHMEM_HUGE_DENY
|| sgp_huge
== SGP_NOHUGE
)
1812 if (shmem_huge
== SHMEM_HUGE_FORCE
)
1814 switch (sbinfo
->huge
) {
1815 case SHMEM_HUGE_NEVER
:
1817 case SHMEM_HUGE_WITHIN_SIZE
: {
1821 off
= round_up(index
, HPAGE_PMD_NR
);
1822 i_size
= round_up(i_size_read(inode
), PAGE_SIZE
);
1823 if (i_size
>= HPAGE_PMD_SIZE
&&
1824 i_size
>> PAGE_SHIFT
>= off
)
1829 case SHMEM_HUGE_ADVISE
:
1830 if (sgp_huge
== SGP_HUGE
)
1832 /* TODO: implement fadvise() hints */
1837 page
= shmem_alloc_and_acct_page(gfp
, inode
, index
, true);
1840 page
= shmem_alloc_and_acct_page(gfp
, inode
,
1846 error
= PTR_ERR(page
);
1848 if (error
!= -ENOSPC
)
1851 * Try to reclaim some space by splitting a huge page
1852 * beyond i_size on the filesystem.
1857 ret
= shmem_unused_huge_shrink(sbinfo
, NULL
, 1);
1858 if (ret
== SHRINK_STOP
)
1866 if (PageTransHuge(page
))
1867 hindex
= round_down(index
, HPAGE_PMD_NR
);
1871 if (sgp
== SGP_WRITE
)
1872 __SetPageReferenced(page
);
1874 error
= mem_cgroup_try_charge_delay(page
, charge_mm
, gfp
, &memcg
,
1875 PageTransHuge(page
));
1877 if (PageTransHuge(page
)) {
1878 count_vm_event(THP_FILE_FALLBACK
);
1879 count_vm_event(THP_FILE_FALLBACK_CHARGE
);
1883 error
= shmem_add_to_page_cache(page
, mapping
, hindex
,
1884 NULL
, gfp
& GFP_RECLAIM_MASK
);
1886 mem_cgroup_cancel_charge(page
, memcg
,
1887 PageTransHuge(page
));
1890 mem_cgroup_commit_charge(page
, memcg
, false,
1891 PageTransHuge(page
));
1892 lru_cache_add_anon(page
);
1894 spin_lock_irq(&info
->lock
);
1895 info
->alloced
+= compound_nr(page
);
1896 inode
->i_blocks
+= BLOCKS_PER_PAGE
<< compound_order(page
);
1897 shmem_recalc_inode(inode
);
1898 spin_unlock_irq(&info
->lock
);
1901 if (PageTransHuge(page
) &&
1902 DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
) <
1903 hindex
+ HPAGE_PMD_NR
- 1) {
1905 * Part of the huge page is beyond i_size: subject
1906 * to shrink under memory pressure.
1908 spin_lock(&sbinfo
->shrinklist_lock
);
1910 * _careful to defend against unlocked access to
1911 * ->shrink_list in shmem_unused_huge_shrink()
1913 if (list_empty_careful(&info
->shrinklist
)) {
1914 list_add_tail(&info
->shrinklist
,
1915 &sbinfo
->shrinklist
);
1916 sbinfo
->shrinklist_len
++;
1918 spin_unlock(&sbinfo
->shrinklist_lock
);
1922 * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
1924 if (sgp
== SGP_FALLOC
)
1928 * Let SGP_WRITE caller clear ends if write does not fill page;
1929 * but SGP_FALLOC on a page fallocated earlier must initialize
1930 * it now, lest undo on failure cancel our earlier guarantee.
1932 if (sgp
!= SGP_WRITE
&& !PageUptodate(page
)) {
1933 struct page
*head
= compound_head(page
);
1936 for (i
= 0; i
< compound_nr(head
); i
++) {
1937 clear_highpage(head
+ i
);
1938 flush_dcache_page(head
+ i
);
1940 SetPageUptodate(head
);
1943 /* Perhaps the file has been truncated since we checked */
1944 if (sgp
<= SGP_CACHE
&&
1945 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1947 ClearPageDirty(page
);
1948 delete_from_page_cache(page
);
1949 spin_lock_irq(&info
->lock
);
1950 shmem_recalc_inode(inode
);
1951 spin_unlock_irq(&info
->lock
);
1956 *pagep
= page
+ index
- hindex
;
1963 shmem_inode_unacct_blocks(inode
, compound_nr(page
));
1965 if (PageTransHuge(page
)) {
1975 if (error
== -ENOSPC
&& !once
++) {
1976 spin_lock_irq(&info
->lock
);
1977 shmem_recalc_inode(inode
);
1978 spin_unlock_irq(&info
->lock
);
1981 if (error
== -EEXIST
)
1987 * This is like autoremove_wake_function, but it removes the wait queue
1988 * entry unconditionally - even if something else had already woken the
1991 static int synchronous_wake_function(wait_queue_entry_t
*wait
, unsigned mode
, int sync
, void *key
)
1993 int ret
= default_wake_function(wait
, mode
, sync
, key
);
1994 list_del_init(&wait
->entry
);
1998 static vm_fault_t
shmem_fault(struct vm_fault
*vmf
)
2000 struct vm_area_struct
*vma
= vmf
->vma
;
2001 struct inode
*inode
= file_inode(vma
->vm_file
);
2002 gfp_t gfp
= mapping_gfp_mask(inode
->i_mapping
);
2005 vm_fault_t ret
= VM_FAULT_LOCKED
;
2008 * Trinity finds that probing a hole which tmpfs is punching can
2009 * prevent the hole-punch from ever completing: which in turn
2010 * locks writers out with its hold on i_mutex. So refrain from
2011 * faulting pages into the hole while it's being punched. Although
2012 * shmem_undo_range() does remove the additions, it may be unable to
2013 * keep up, as each new page needs its own unmap_mapping_range() call,
2014 * and the i_mmap tree grows ever slower to scan if new vmas are added.
2016 * It does not matter if we sometimes reach this check just before the
2017 * hole-punch begins, so that one fault then races with the punch:
2018 * we just need to make racing faults a rare case.
2020 * The implementation below would be much simpler if we just used a
2021 * standard mutex or completion: but we cannot take i_mutex in fault,
2022 * and bloating every shmem inode for this unlikely case would be sad.
2024 if (unlikely(inode
->i_private
)) {
2025 struct shmem_falloc
*shmem_falloc
;
2027 spin_lock(&inode
->i_lock
);
2028 shmem_falloc
= inode
->i_private
;
2030 shmem_falloc
->waitq
&&
2031 vmf
->pgoff
>= shmem_falloc
->start
&&
2032 vmf
->pgoff
< shmem_falloc
->next
) {
2034 wait_queue_head_t
*shmem_falloc_waitq
;
2035 DEFINE_WAIT_FUNC(shmem_fault_wait
, synchronous_wake_function
);
2037 ret
= VM_FAULT_NOPAGE
;
2038 fpin
= maybe_unlock_mmap_for_io(vmf
, NULL
);
2040 ret
= VM_FAULT_RETRY
;
2042 shmem_falloc_waitq
= shmem_falloc
->waitq
;
2043 prepare_to_wait(shmem_falloc_waitq
, &shmem_fault_wait
,
2044 TASK_UNINTERRUPTIBLE
);
2045 spin_unlock(&inode
->i_lock
);
2049 * shmem_falloc_waitq points into the shmem_fallocate()
2050 * stack of the hole-punching task: shmem_falloc_waitq
2051 * is usually invalid by the time we reach here, but
2052 * finish_wait() does not dereference it in that case;
2053 * though i_lock needed lest racing with wake_up_all().
2055 spin_lock(&inode
->i_lock
);
2056 finish_wait(shmem_falloc_waitq
, &shmem_fault_wait
);
2057 spin_unlock(&inode
->i_lock
);
2063 spin_unlock(&inode
->i_lock
);
2068 if ((vma
->vm_flags
& VM_NOHUGEPAGE
) ||
2069 test_bit(MMF_DISABLE_THP
, &vma
->vm_mm
->flags
))
2071 else if (vma
->vm_flags
& VM_HUGEPAGE
)
2074 err
= shmem_getpage_gfp(inode
, vmf
->pgoff
, &vmf
->page
, sgp
,
2075 gfp
, vma
, vmf
, &ret
);
2077 return vmf_error(err
);
2081 unsigned long shmem_get_unmapped_area(struct file
*file
,
2082 unsigned long uaddr
, unsigned long len
,
2083 unsigned long pgoff
, unsigned long flags
)
2085 unsigned long (*get_area
)(struct file
*,
2086 unsigned long, unsigned long, unsigned long, unsigned long);
2088 unsigned long offset
;
2089 unsigned long inflated_len
;
2090 unsigned long inflated_addr
;
2091 unsigned long inflated_offset
;
2093 if (len
> TASK_SIZE
)
2096 get_area
= current
->mm
->get_unmapped_area
;
2097 addr
= get_area(file
, uaddr
, len
, pgoff
, flags
);
2099 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
))
2101 if (IS_ERR_VALUE(addr
))
2103 if (addr
& ~PAGE_MASK
)
2105 if (addr
> TASK_SIZE
- len
)
2108 if (shmem_huge
== SHMEM_HUGE_DENY
)
2110 if (len
< HPAGE_PMD_SIZE
)
2112 if (flags
& MAP_FIXED
)
2115 * Our priority is to support MAP_SHARED mapped hugely;
2116 * and support MAP_PRIVATE mapped hugely too, until it is COWed.
2117 * But if caller specified an address hint and we allocated area there
2118 * successfully, respect that as before.
2123 if (shmem_huge
!= SHMEM_HUGE_FORCE
) {
2124 struct super_block
*sb
;
2127 VM_BUG_ON(file
->f_op
!= &shmem_file_operations
);
2128 sb
= file_inode(file
)->i_sb
;
2131 * Called directly from mm/mmap.c, or drivers/char/mem.c
2132 * for "/dev/zero", to create a shared anonymous object.
2134 if (IS_ERR(shm_mnt
))
2136 sb
= shm_mnt
->mnt_sb
;
2138 if (SHMEM_SB(sb
)->huge
== SHMEM_HUGE_NEVER
)
2142 offset
= (pgoff
<< PAGE_SHIFT
) & (HPAGE_PMD_SIZE
-1);
2143 if (offset
&& offset
+ len
< 2 * HPAGE_PMD_SIZE
)
2145 if ((addr
& (HPAGE_PMD_SIZE
-1)) == offset
)
2148 inflated_len
= len
+ HPAGE_PMD_SIZE
- PAGE_SIZE
;
2149 if (inflated_len
> TASK_SIZE
)
2151 if (inflated_len
< len
)
2154 inflated_addr
= get_area(NULL
, uaddr
, inflated_len
, 0, flags
);
2155 if (IS_ERR_VALUE(inflated_addr
))
2157 if (inflated_addr
& ~PAGE_MASK
)
2160 inflated_offset
= inflated_addr
& (HPAGE_PMD_SIZE
-1);
2161 inflated_addr
+= offset
- inflated_offset
;
2162 if (inflated_offset
> offset
)
2163 inflated_addr
+= HPAGE_PMD_SIZE
;
2165 if (inflated_addr
> TASK_SIZE
- len
)
2167 return inflated_addr
;
2171 static int shmem_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
2173 struct inode
*inode
= file_inode(vma
->vm_file
);
2174 return mpol_set_shared_policy(&SHMEM_I(inode
)->policy
, vma
, mpol
);
2177 static struct mempolicy
*shmem_get_policy(struct vm_area_struct
*vma
,
2180 struct inode
*inode
= file_inode(vma
->vm_file
);
2183 index
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2184 return mpol_shared_policy_lookup(&SHMEM_I(inode
)->policy
, index
);
2188 int shmem_lock(struct file
*file
, int lock
, struct user_struct
*user
)
2190 struct inode
*inode
= file_inode(file
);
2191 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2192 int retval
= -ENOMEM
;
2194 spin_lock_irq(&info
->lock
);
2195 if (lock
&& !(info
->flags
& VM_LOCKED
)) {
2196 if (!user_shm_lock(inode
->i_size
, user
))
2198 info
->flags
|= VM_LOCKED
;
2199 mapping_set_unevictable(file
->f_mapping
);
2201 if (!lock
&& (info
->flags
& VM_LOCKED
) && user
) {
2202 user_shm_unlock(inode
->i_size
, user
);
2203 info
->flags
&= ~VM_LOCKED
;
2204 mapping_clear_unevictable(file
->f_mapping
);
2209 spin_unlock_irq(&info
->lock
);
2213 static int shmem_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2215 struct shmem_inode_info
*info
= SHMEM_I(file_inode(file
));
2217 if (info
->seals
& F_SEAL_FUTURE_WRITE
) {
2219 * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
2220 * "future write" seal active.
2222 if ((vma
->vm_flags
& VM_SHARED
) && (vma
->vm_flags
& VM_WRITE
))
2226 * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
2227 * MAP_SHARED and read-only, take care to not allow mprotect to
2228 * revert protections on such mappings. Do this only for shared
2229 * mappings. For private mappings, don't need to mask
2230 * VM_MAYWRITE as we still want them to be COW-writable.
2232 if (vma
->vm_flags
& VM_SHARED
)
2233 vma
->vm_flags
&= ~(VM_MAYWRITE
);
2236 file_accessed(file
);
2237 vma
->vm_ops
= &shmem_vm_ops
;
2238 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
2239 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
2240 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
2241 khugepaged_enter(vma
, vma
->vm_flags
);
2246 static struct inode
*shmem_get_inode(struct super_block
*sb
, const struct inode
*dir
,
2247 umode_t mode
, dev_t dev
, unsigned long flags
)
2249 struct inode
*inode
;
2250 struct shmem_inode_info
*info
;
2251 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
2253 if (shmem_reserve_inode(sb
))
2256 inode
= new_inode(sb
);
2258 inode
->i_ino
= get_next_ino();
2259 inode_init_owner(inode
, dir
, mode
);
2260 inode
->i_blocks
= 0;
2261 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= current_time(inode
);
2262 inode
->i_generation
= prandom_u32();
2263 info
= SHMEM_I(inode
);
2264 memset(info
, 0, (char *)inode
- (char *)info
);
2265 spin_lock_init(&info
->lock
);
2266 atomic_set(&info
->stop_eviction
, 0);
2267 info
->seals
= F_SEAL_SEAL
;
2268 info
->flags
= flags
& VM_NORESERVE
;
2269 INIT_LIST_HEAD(&info
->shrinklist
);
2270 INIT_LIST_HEAD(&info
->swaplist
);
2271 simple_xattrs_init(&info
->xattrs
);
2272 cache_no_acl(inode
);
2274 switch (mode
& S_IFMT
) {
2276 inode
->i_op
= &shmem_special_inode_operations
;
2277 init_special_inode(inode
, mode
, dev
);
2280 inode
->i_mapping
->a_ops
= &shmem_aops
;
2281 inode
->i_op
= &shmem_inode_operations
;
2282 inode
->i_fop
= &shmem_file_operations
;
2283 mpol_shared_policy_init(&info
->policy
,
2284 shmem_get_sbmpol(sbinfo
));
2288 /* Some things misbehave if size == 0 on a directory */
2289 inode
->i_size
= 2 * BOGO_DIRENT_SIZE
;
2290 inode
->i_op
= &shmem_dir_inode_operations
;
2291 inode
->i_fop
= &simple_dir_operations
;
2295 * Must not load anything in the rbtree,
2296 * mpol_free_shared_policy will not be called.
2298 mpol_shared_policy_init(&info
->policy
, NULL
);
2302 lockdep_annotate_inode_mutex_key(inode
);
2304 shmem_free_inode(sb
);
2308 bool shmem_mapping(struct address_space
*mapping
)
2310 return mapping
->a_ops
== &shmem_aops
;
2313 static int shmem_mfill_atomic_pte(struct mm_struct
*dst_mm
,
2315 struct vm_area_struct
*dst_vma
,
2316 unsigned long dst_addr
,
2317 unsigned long src_addr
,
2319 struct page
**pagep
)
2321 struct inode
*inode
= file_inode(dst_vma
->vm_file
);
2322 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2323 struct address_space
*mapping
= inode
->i_mapping
;
2324 gfp_t gfp
= mapping_gfp_mask(mapping
);
2325 pgoff_t pgoff
= linear_page_index(dst_vma
, dst_addr
);
2326 struct mem_cgroup
*memcg
;
2330 pte_t _dst_pte
, *dst_pte
;
2332 pgoff_t offset
, max_off
;
2335 if (!shmem_inode_acct_block(inode
, 1))
2339 page
= shmem_alloc_page(gfp
, info
, pgoff
);
2341 goto out_unacct_blocks
;
2343 if (!zeropage
) { /* mcopy_atomic */
2344 page_kaddr
= kmap_atomic(page
);
2345 ret
= copy_from_user(page_kaddr
,
2346 (const void __user
*)src_addr
,
2348 kunmap_atomic(page_kaddr
);
2350 /* fallback to copy_from_user outside mmap_sem */
2351 if (unlikely(ret
)) {
2353 shmem_inode_unacct_blocks(inode
, 1);
2354 /* don't free the page */
2357 } else { /* mfill_zeropage_atomic */
2358 clear_highpage(page
);
2365 VM_BUG_ON(PageLocked(page
) || PageSwapBacked(page
));
2366 __SetPageLocked(page
);
2367 __SetPageSwapBacked(page
);
2368 __SetPageUptodate(page
);
2371 offset
= linear_page_index(dst_vma
, dst_addr
);
2372 max_off
= DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
);
2373 if (unlikely(offset
>= max_off
))
2376 ret
= mem_cgroup_try_charge_delay(page
, dst_mm
, gfp
, &memcg
, false);
2380 ret
= shmem_add_to_page_cache(page
, mapping
, pgoff
, NULL
,
2381 gfp
& GFP_RECLAIM_MASK
);
2383 goto out_release_uncharge
;
2385 mem_cgroup_commit_charge(page
, memcg
, false, false);
2387 _dst_pte
= mk_pte(page
, dst_vma
->vm_page_prot
);
2388 if (dst_vma
->vm_flags
& VM_WRITE
)
2389 _dst_pte
= pte_mkwrite(pte_mkdirty(_dst_pte
));
2392 * We don't set the pte dirty if the vma has no
2393 * VM_WRITE permission, so mark the page dirty or it
2394 * could be freed from under us. We could do it
2395 * unconditionally before unlock_page(), but doing it
2396 * only if VM_WRITE is not set is faster.
2398 set_page_dirty(page
);
2401 dst_pte
= pte_offset_map_lock(dst_mm
, dst_pmd
, dst_addr
, &ptl
);
2404 max_off
= DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
);
2405 if (unlikely(offset
>= max_off
))
2406 goto out_release_uncharge_unlock
;
2409 if (!pte_none(*dst_pte
))
2410 goto out_release_uncharge_unlock
;
2412 lru_cache_add_anon(page
);
2414 spin_lock(&info
->lock
);
2416 inode
->i_blocks
+= BLOCKS_PER_PAGE
;
2417 shmem_recalc_inode(inode
);
2418 spin_unlock(&info
->lock
);
2420 inc_mm_counter(dst_mm
, mm_counter_file(page
));
2421 page_add_file_rmap(page
, false);
2422 set_pte_at(dst_mm
, dst_addr
, dst_pte
, _dst_pte
);
2424 /* No need to invalidate - it was non-present before */
2425 update_mmu_cache(dst_vma
, dst_addr
, dst_pte
);
2426 pte_unmap_unlock(dst_pte
, ptl
);
2431 out_release_uncharge_unlock
:
2432 pte_unmap_unlock(dst_pte
, ptl
);
2433 ClearPageDirty(page
);
2434 delete_from_page_cache(page
);
2435 out_release_uncharge
:
2436 mem_cgroup_cancel_charge(page
, memcg
, false);
2441 shmem_inode_unacct_blocks(inode
, 1);
2445 int shmem_mcopy_atomic_pte(struct mm_struct
*dst_mm
,
2447 struct vm_area_struct
*dst_vma
,
2448 unsigned long dst_addr
,
2449 unsigned long src_addr
,
2450 struct page
**pagep
)
2452 return shmem_mfill_atomic_pte(dst_mm
, dst_pmd
, dst_vma
,
2453 dst_addr
, src_addr
, false, pagep
);
2456 int shmem_mfill_zeropage_pte(struct mm_struct
*dst_mm
,
2458 struct vm_area_struct
*dst_vma
,
2459 unsigned long dst_addr
)
2461 struct page
*page
= NULL
;
2463 return shmem_mfill_atomic_pte(dst_mm
, dst_pmd
, dst_vma
,
2464 dst_addr
, 0, true, &page
);
2468 static const struct inode_operations shmem_symlink_inode_operations
;
2469 static const struct inode_operations shmem_short_symlink_operations
;
2471 #ifdef CONFIG_TMPFS_XATTR
2472 static int shmem_initxattrs(struct inode
*, const struct xattr
*, void *);
2474 #define shmem_initxattrs NULL
2478 shmem_write_begin(struct file
*file
, struct address_space
*mapping
,
2479 loff_t pos
, unsigned len
, unsigned flags
,
2480 struct page
**pagep
, void **fsdata
)
2482 struct inode
*inode
= mapping
->host
;
2483 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2484 pgoff_t index
= pos
>> PAGE_SHIFT
;
2486 /* i_mutex is held by caller */
2487 if (unlikely(info
->seals
& (F_SEAL_GROW
|
2488 F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))) {
2489 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))
2491 if ((info
->seals
& F_SEAL_GROW
) && pos
+ len
> inode
->i_size
)
2495 return shmem_getpage(inode
, index
, pagep
, SGP_WRITE
);
2499 shmem_write_end(struct file
*file
, struct address_space
*mapping
,
2500 loff_t pos
, unsigned len
, unsigned copied
,
2501 struct page
*page
, void *fsdata
)
2503 struct inode
*inode
= mapping
->host
;
2505 if (pos
+ copied
> inode
->i_size
)
2506 i_size_write(inode
, pos
+ copied
);
2508 if (!PageUptodate(page
)) {
2509 struct page
*head
= compound_head(page
);
2510 if (PageTransCompound(page
)) {
2513 for (i
= 0; i
< HPAGE_PMD_NR
; i
++) {
2514 if (head
+ i
== page
)
2516 clear_highpage(head
+ i
);
2517 flush_dcache_page(head
+ i
);
2520 if (copied
< PAGE_SIZE
) {
2521 unsigned from
= pos
& (PAGE_SIZE
- 1);
2522 zero_user_segments(page
, 0, from
,
2523 from
+ copied
, PAGE_SIZE
);
2525 SetPageUptodate(head
);
2527 set_page_dirty(page
);
2534 static ssize_t
shmem_file_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
2536 struct file
*file
= iocb
->ki_filp
;
2537 struct inode
*inode
= file_inode(file
);
2538 struct address_space
*mapping
= inode
->i_mapping
;
2540 unsigned long offset
;
2541 enum sgp_type sgp
= SGP_READ
;
2544 loff_t
*ppos
= &iocb
->ki_pos
;
2547 * Might this read be for a stacking filesystem? Then when reading
2548 * holes of a sparse file, we actually need to allocate those pages,
2549 * and even mark them dirty, so it cannot exceed the max_blocks limit.
2551 if (!iter_is_iovec(to
))
2554 index
= *ppos
>> PAGE_SHIFT
;
2555 offset
= *ppos
& ~PAGE_MASK
;
2558 struct page
*page
= NULL
;
2560 unsigned long nr
, ret
;
2561 loff_t i_size
= i_size_read(inode
);
2563 end_index
= i_size
>> PAGE_SHIFT
;
2564 if (index
> end_index
)
2566 if (index
== end_index
) {
2567 nr
= i_size
& ~PAGE_MASK
;
2572 error
= shmem_getpage(inode
, index
, &page
, sgp
);
2574 if (error
== -EINVAL
)
2579 if (sgp
== SGP_CACHE
)
2580 set_page_dirty(page
);
2585 * We must evaluate after, since reads (unlike writes)
2586 * are called without i_mutex protection against truncate
2589 i_size
= i_size_read(inode
);
2590 end_index
= i_size
>> PAGE_SHIFT
;
2591 if (index
== end_index
) {
2592 nr
= i_size
& ~PAGE_MASK
;
2603 * If users can be writing to this page using arbitrary
2604 * virtual addresses, take care about potential aliasing
2605 * before reading the page on the kernel side.
2607 if (mapping_writably_mapped(mapping
))
2608 flush_dcache_page(page
);
2610 * Mark the page accessed if we read the beginning.
2613 mark_page_accessed(page
);
2615 page
= ZERO_PAGE(0);
2620 * Ok, we have the page, and it's up-to-date, so
2621 * now we can copy it to user space...
2623 ret
= copy_page_to_iter(page
, offset
, nr
, to
);
2626 index
+= offset
>> PAGE_SHIFT
;
2627 offset
&= ~PAGE_MASK
;
2630 if (!iov_iter_count(to
))
2639 *ppos
= ((loff_t
) index
<< PAGE_SHIFT
) + offset
;
2640 file_accessed(file
);
2641 return retval
? retval
: error
;
2645 * llseek SEEK_DATA or SEEK_HOLE through the page cache.
2647 static pgoff_t
shmem_seek_hole_data(struct address_space
*mapping
,
2648 pgoff_t index
, pgoff_t end
, int whence
)
2651 struct pagevec pvec
;
2652 pgoff_t indices
[PAGEVEC_SIZE
];
2656 pagevec_init(&pvec
);
2657 pvec
.nr
= 1; /* start small: we may be there already */
2659 pvec
.nr
= find_get_entries(mapping
, index
,
2660 pvec
.nr
, pvec
.pages
, indices
);
2662 if (whence
== SEEK_DATA
)
2666 for (i
= 0; i
< pvec
.nr
; i
++, index
++) {
2667 if (index
< indices
[i
]) {
2668 if (whence
== SEEK_HOLE
) {
2674 page
= pvec
.pages
[i
];
2675 if (page
&& !xa_is_value(page
)) {
2676 if (!PageUptodate(page
))
2680 (page
&& whence
== SEEK_DATA
) ||
2681 (!page
&& whence
== SEEK_HOLE
)) {
2686 pagevec_remove_exceptionals(&pvec
);
2687 pagevec_release(&pvec
);
2688 pvec
.nr
= PAGEVEC_SIZE
;
2694 static loff_t
shmem_file_llseek(struct file
*file
, loff_t offset
, int whence
)
2696 struct address_space
*mapping
= file
->f_mapping
;
2697 struct inode
*inode
= mapping
->host
;
2701 if (whence
!= SEEK_DATA
&& whence
!= SEEK_HOLE
)
2702 return generic_file_llseek_size(file
, offset
, whence
,
2703 MAX_LFS_FILESIZE
, i_size_read(inode
));
2705 /* We're holding i_mutex so we can access i_size directly */
2707 if (offset
< 0 || offset
>= inode
->i_size
)
2710 start
= offset
>> PAGE_SHIFT
;
2711 end
= (inode
->i_size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2712 new_offset
= shmem_seek_hole_data(mapping
, start
, end
, whence
);
2713 new_offset
<<= PAGE_SHIFT
;
2714 if (new_offset
> offset
) {
2715 if (new_offset
< inode
->i_size
)
2716 offset
= new_offset
;
2717 else if (whence
== SEEK_DATA
)
2720 offset
= inode
->i_size
;
2725 offset
= vfs_setpos(file
, offset
, MAX_LFS_FILESIZE
);
2726 inode_unlock(inode
);
2730 static long shmem_fallocate(struct file
*file
, int mode
, loff_t offset
,
2733 struct inode
*inode
= file_inode(file
);
2734 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
2735 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2736 struct shmem_falloc shmem_falloc
;
2737 pgoff_t start
, index
, end
;
2740 if (mode
& ~(FALLOC_FL_KEEP_SIZE
| FALLOC_FL_PUNCH_HOLE
))
2745 if (mode
& FALLOC_FL_PUNCH_HOLE
) {
2746 struct address_space
*mapping
= file
->f_mapping
;
2747 loff_t unmap_start
= round_up(offset
, PAGE_SIZE
);
2748 loff_t unmap_end
= round_down(offset
+ len
, PAGE_SIZE
) - 1;
2749 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq
);
2751 /* protected by i_mutex */
2752 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
)) {
2757 shmem_falloc
.waitq
= &shmem_falloc_waitq
;
2758 shmem_falloc
.start
= (u64
)unmap_start
>> PAGE_SHIFT
;
2759 shmem_falloc
.next
= (unmap_end
+ 1) >> PAGE_SHIFT
;
2760 spin_lock(&inode
->i_lock
);
2761 inode
->i_private
= &shmem_falloc
;
2762 spin_unlock(&inode
->i_lock
);
2764 if ((u64
)unmap_end
> (u64
)unmap_start
)
2765 unmap_mapping_range(mapping
, unmap_start
,
2766 1 + unmap_end
- unmap_start
, 0);
2767 shmem_truncate_range(inode
, offset
, offset
+ len
- 1);
2768 /* No need to unmap again: hole-punching leaves COWed pages */
2770 spin_lock(&inode
->i_lock
);
2771 inode
->i_private
= NULL
;
2772 wake_up_all(&shmem_falloc_waitq
);
2773 WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq
.head
));
2774 spin_unlock(&inode
->i_lock
);
2779 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
2780 error
= inode_newsize_ok(inode
, offset
+ len
);
2784 if ((info
->seals
& F_SEAL_GROW
) && offset
+ len
> inode
->i_size
) {
2789 start
= offset
>> PAGE_SHIFT
;
2790 end
= (offset
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2791 /* Try to avoid a swapstorm if len is impossible to satisfy */
2792 if (sbinfo
->max_blocks
&& end
- start
> sbinfo
->max_blocks
) {
2797 shmem_falloc
.waitq
= NULL
;
2798 shmem_falloc
.start
= start
;
2799 shmem_falloc
.next
= start
;
2800 shmem_falloc
.nr_falloced
= 0;
2801 shmem_falloc
.nr_unswapped
= 0;
2802 spin_lock(&inode
->i_lock
);
2803 inode
->i_private
= &shmem_falloc
;
2804 spin_unlock(&inode
->i_lock
);
2806 for (index
= start
; index
< end
; index
++) {
2810 * Good, the fallocate(2) manpage permits EINTR: we may have
2811 * been interrupted because we are using up too much memory.
2813 if (signal_pending(current
))
2815 else if (shmem_falloc
.nr_unswapped
> shmem_falloc
.nr_falloced
)
2818 error
= shmem_getpage(inode
, index
, &page
, SGP_FALLOC
);
2820 /* Remove the !PageUptodate pages we added */
2821 if (index
> start
) {
2822 shmem_undo_range(inode
,
2823 (loff_t
)start
<< PAGE_SHIFT
,
2824 ((loff_t
)index
<< PAGE_SHIFT
) - 1, true);
2830 * Inform shmem_writepage() how far we have reached.
2831 * No need for lock or barrier: we have the page lock.
2833 shmem_falloc
.next
++;
2834 if (!PageUptodate(page
))
2835 shmem_falloc
.nr_falloced
++;
2838 * If !PageUptodate, leave it that way so that freeable pages
2839 * can be recognized if we need to rollback on error later.
2840 * But set_page_dirty so that memory pressure will swap rather
2841 * than free the pages we are allocating (and SGP_CACHE pages
2842 * might still be clean: we now need to mark those dirty too).
2844 set_page_dirty(page
);
2850 if (!(mode
& FALLOC_FL_KEEP_SIZE
) && offset
+ len
> inode
->i_size
)
2851 i_size_write(inode
, offset
+ len
);
2852 inode
->i_ctime
= current_time(inode
);
2854 spin_lock(&inode
->i_lock
);
2855 inode
->i_private
= NULL
;
2856 spin_unlock(&inode
->i_lock
);
2858 inode_unlock(inode
);
2862 static int shmem_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
2864 struct shmem_sb_info
*sbinfo
= SHMEM_SB(dentry
->d_sb
);
2866 buf
->f_type
= TMPFS_MAGIC
;
2867 buf
->f_bsize
= PAGE_SIZE
;
2868 buf
->f_namelen
= NAME_MAX
;
2869 if (sbinfo
->max_blocks
) {
2870 buf
->f_blocks
= sbinfo
->max_blocks
;
2872 buf
->f_bfree
= sbinfo
->max_blocks
-
2873 percpu_counter_sum(&sbinfo
->used_blocks
);
2875 if (sbinfo
->max_inodes
) {
2876 buf
->f_files
= sbinfo
->max_inodes
;
2877 buf
->f_ffree
= sbinfo
->free_inodes
;
2879 /* else leave those fields 0 like simple_statfs */
2884 * File creation. Allocate an inode, and we're done..
2887 shmem_mknod(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
, dev_t dev
)
2889 struct inode
*inode
;
2890 int error
= -ENOSPC
;
2892 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, dev
, VM_NORESERVE
);
2894 error
= simple_acl_create(dir
, inode
);
2897 error
= security_inode_init_security(inode
, dir
,
2899 shmem_initxattrs
, NULL
);
2900 if (error
&& error
!= -EOPNOTSUPP
)
2904 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2905 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
2906 d_instantiate(dentry
, inode
);
2907 dget(dentry
); /* Extra count - pin the dentry in core */
2916 shmem_tmpfile(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
)
2918 struct inode
*inode
;
2919 int error
= -ENOSPC
;
2921 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, 0, VM_NORESERVE
);
2923 error
= security_inode_init_security(inode
, dir
,
2925 shmem_initxattrs
, NULL
);
2926 if (error
&& error
!= -EOPNOTSUPP
)
2928 error
= simple_acl_create(dir
, inode
);
2931 d_tmpfile(dentry
, inode
);
2939 static int shmem_mkdir(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
)
2943 if ((error
= shmem_mknod(dir
, dentry
, mode
| S_IFDIR
, 0)))
2949 static int shmem_create(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
,
2952 return shmem_mknod(dir
, dentry
, mode
| S_IFREG
, 0);
2958 static int shmem_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*dentry
)
2960 struct inode
*inode
= d_inode(old_dentry
);
2964 * No ordinary (disk based) filesystem counts links as inodes;
2965 * but each new link needs a new dentry, pinning lowmem, and
2966 * tmpfs dentries cannot be pruned until they are unlinked.
2967 * But if an O_TMPFILE file is linked into the tmpfs, the
2968 * first link must skip that, to get the accounting right.
2970 if (inode
->i_nlink
) {
2971 ret
= shmem_reserve_inode(inode
->i_sb
);
2976 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2977 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2979 ihold(inode
); /* New dentry reference */
2980 dget(dentry
); /* Extra pinning count for the created dentry */
2981 d_instantiate(dentry
, inode
);
2986 static int shmem_unlink(struct inode
*dir
, struct dentry
*dentry
)
2988 struct inode
*inode
= d_inode(dentry
);
2990 if (inode
->i_nlink
> 1 && !S_ISDIR(inode
->i_mode
))
2991 shmem_free_inode(inode
->i_sb
);
2993 dir
->i_size
-= BOGO_DIRENT_SIZE
;
2994 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2996 dput(dentry
); /* Undo the count from "create" - this does all the work */
3000 static int shmem_rmdir(struct inode
*dir
, struct dentry
*dentry
)
3002 if (!simple_empty(dentry
))
3005 drop_nlink(d_inode(dentry
));
3007 return shmem_unlink(dir
, dentry
);
3010 static int shmem_exchange(struct inode
*old_dir
, struct dentry
*old_dentry
, struct inode
*new_dir
, struct dentry
*new_dentry
)
3012 bool old_is_dir
= d_is_dir(old_dentry
);
3013 bool new_is_dir
= d_is_dir(new_dentry
);
3015 if (old_dir
!= new_dir
&& old_is_dir
!= new_is_dir
) {
3017 drop_nlink(old_dir
);
3020 drop_nlink(new_dir
);
3024 old_dir
->i_ctime
= old_dir
->i_mtime
=
3025 new_dir
->i_ctime
= new_dir
->i_mtime
=
3026 d_inode(old_dentry
)->i_ctime
=
3027 d_inode(new_dentry
)->i_ctime
= current_time(old_dir
);
3032 static int shmem_whiteout(struct inode
*old_dir
, struct dentry
*old_dentry
)
3034 struct dentry
*whiteout
;
3037 whiteout
= d_alloc(old_dentry
->d_parent
, &old_dentry
->d_name
);
3041 error
= shmem_mknod(old_dir
, whiteout
,
3042 S_IFCHR
| WHITEOUT_MODE
, WHITEOUT_DEV
);
3048 * Cheat and hash the whiteout while the old dentry is still in
3049 * place, instead of playing games with FS_RENAME_DOES_D_MOVE.
3051 * d_lookup() will consistently find one of them at this point,
3052 * not sure which one, but that isn't even important.
3059 * The VFS layer already does all the dentry stuff for rename,
3060 * we just have to decrement the usage count for the target if
3061 * it exists so that the VFS layer correctly free's it when it
3064 static int shmem_rename2(struct inode
*old_dir
, struct dentry
*old_dentry
, struct inode
*new_dir
, struct dentry
*new_dentry
, unsigned int flags
)
3066 struct inode
*inode
= d_inode(old_dentry
);
3067 int they_are_dirs
= S_ISDIR(inode
->i_mode
);
3069 if (flags
& ~(RENAME_NOREPLACE
| RENAME_EXCHANGE
| RENAME_WHITEOUT
))
3072 if (flags
& RENAME_EXCHANGE
)
3073 return shmem_exchange(old_dir
, old_dentry
, new_dir
, new_dentry
);
3075 if (!simple_empty(new_dentry
))
3078 if (flags
& RENAME_WHITEOUT
) {
3081 error
= shmem_whiteout(old_dir
, old_dentry
);
3086 if (d_really_is_positive(new_dentry
)) {
3087 (void) shmem_unlink(new_dir
, new_dentry
);
3088 if (they_are_dirs
) {
3089 drop_nlink(d_inode(new_dentry
));
3090 drop_nlink(old_dir
);
3092 } else if (they_are_dirs
) {
3093 drop_nlink(old_dir
);
3097 old_dir
->i_size
-= BOGO_DIRENT_SIZE
;
3098 new_dir
->i_size
+= BOGO_DIRENT_SIZE
;
3099 old_dir
->i_ctime
= old_dir
->i_mtime
=
3100 new_dir
->i_ctime
= new_dir
->i_mtime
=
3101 inode
->i_ctime
= current_time(old_dir
);
3105 static int shmem_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *symname
)
3109 struct inode
*inode
;
3112 len
= strlen(symname
) + 1;
3113 if (len
> PAGE_SIZE
)
3114 return -ENAMETOOLONG
;
3116 inode
= shmem_get_inode(dir
->i_sb
, dir
, S_IFLNK
| 0777, 0,
3121 error
= security_inode_init_security(inode
, dir
, &dentry
->d_name
,
3122 shmem_initxattrs
, NULL
);
3124 if (error
!= -EOPNOTSUPP
) {
3131 inode
->i_size
= len
-1;
3132 if (len
<= SHORT_SYMLINK_LEN
) {
3133 inode
->i_link
= kmemdup(symname
, len
, GFP_KERNEL
);
3134 if (!inode
->i_link
) {
3138 inode
->i_op
= &shmem_short_symlink_operations
;
3140 inode_nohighmem(inode
);
3141 error
= shmem_getpage(inode
, 0, &page
, SGP_WRITE
);
3146 inode
->i_mapping
->a_ops
= &shmem_aops
;
3147 inode
->i_op
= &shmem_symlink_inode_operations
;
3148 memcpy(page_address(page
), symname
, len
);
3149 SetPageUptodate(page
);
3150 set_page_dirty(page
);
3154 dir
->i_size
+= BOGO_DIRENT_SIZE
;
3155 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
3156 d_instantiate(dentry
, inode
);
3161 static void shmem_put_link(void *arg
)
3163 mark_page_accessed(arg
);
3167 static const char *shmem_get_link(struct dentry
*dentry
,
3168 struct inode
*inode
,
3169 struct delayed_call
*done
)
3171 struct page
*page
= NULL
;
3174 page
= find_get_page(inode
->i_mapping
, 0);
3176 return ERR_PTR(-ECHILD
);
3177 if (!PageUptodate(page
)) {
3179 return ERR_PTR(-ECHILD
);
3182 error
= shmem_getpage(inode
, 0, &page
, SGP_READ
);
3184 return ERR_PTR(error
);
3187 set_delayed_call(done
, shmem_put_link
, page
);
3188 return page_address(page
);
3191 #ifdef CONFIG_TMPFS_XATTR
3193 * Superblocks without xattr inode operations may get some security.* xattr
3194 * support from the LSM "for free". As soon as we have any other xattrs
3195 * like ACLs, we also need to implement the security.* handlers at
3196 * filesystem level, though.
3200 * Callback for security_inode_init_security() for acquiring xattrs.
3202 static int shmem_initxattrs(struct inode
*inode
,
3203 const struct xattr
*xattr_array
,
3206 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3207 const struct xattr
*xattr
;
3208 struct simple_xattr
*new_xattr
;
3211 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
3212 new_xattr
= simple_xattr_alloc(xattr
->value
, xattr
->value_len
);
3216 len
= strlen(xattr
->name
) + 1;
3217 new_xattr
->name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+ len
,
3219 if (!new_xattr
->name
) {
3224 memcpy(new_xattr
->name
, XATTR_SECURITY_PREFIX
,
3225 XATTR_SECURITY_PREFIX_LEN
);
3226 memcpy(new_xattr
->name
+ XATTR_SECURITY_PREFIX_LEN
,
3229 simple_xattr_list_add(&info
->xattrs
, new_xattr
);
3235 static int shmem_xattr_handler_get(const struct xattr_handler
*handler
,
3236 struct dentry
*unused
, struct inode
*inode
,
3237 const char *name
, void *buffer
, size_t size
)
3239 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3241 name
= xattr_full_name(handler
, name
);
3242 return simple_xattr_get(&info
->xattrs
, name
, buffer
, size
);
3245 static int shmem_xattr_handler_set(const struct xattr_handler
*handler
,
3246 struct dentry
*unused
, struct inode
*inode
,
3247 const char *name
, const void *value
,
3248 size_t size
, int flags
)
3250 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3252 name
= xattr_full_name(handler
, name
);
3253 return simple_xattr_set(&info
->xattrs
, name
, value
, size
, flags
, NULL
);
3256 static const struct xattr_handler shmem_security_xattr_handler
= {
3257 .prefix
= XATTR_SECURITY_PREFIX
,
3258 .get
= shmem_xattr_handler_get
,
3259 .set
= shmem_xattr_handler_set
,
3262 static const struct xattr_handler shmem_trusted_xattr_handler
= {
3263 .prefix
= XATTR_TRUSTED_PREFIX
,
3264 .get
= shmem_xattr_handler_get
,
3265 .set
= shmem_xattr_handler_set
,
3268 static const struct xattr_handler
*shmem_xattr_handlers
[] = {
3269 #ifdef CONFIG_TMPFS_POSIX_ACL
3270 &posix_acl_access_xattr_handler
,
3271 &posix_acl_default_xattr_handler
,
3273 &shmem_security_xattr_handler
,
3274 &shmem_trusted_xattr_handler
,
3278 static ssize_t
shmem_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
3280 struct shmem_inode_info
*info
= SHMEM_I(d_inode(dentry
));
3281 return simple_xattr_list(d_inode(dentry
), &info
->xattrs
, buffer
, size
);
3283 #endif /* CONFIG_TMPFS_XATTR */
3285 static const struct inode_operations shmem_short_symlink_operations
= {
3286 .get_link
= simple_get_link
,
3287 #ifdef CONFIG_TMPFS_XATTR
3288 .listxattr
= shmem_listxattr
,
3292 static const struct inode_operations shmem_symlink_inode_operations
= {
3293 .get_link
= shmem_get_link
,
3294 #ifdef CONFIG_TMPFS_XATTR
3295 .listxattr
= shmem_listxattr
,
3299 static struct dentry
*shmem_get_parent(struct dentry
*child
)
3301 return ERR_PTR(-ESTALE
);
3304 static int shmem_match(struct inode
*ino
, void *vfh
)
3308 inum
= (inum
<< 32) | fh
[1];
3309 return ino
->i_ino
== inum
&& fh
[0] == ino
->i_generation
;
3312 /* Find any alias of inode, but prefer a hashed alias */
3313 static struct dentry
*shmem_find_alias(struct inode
*inode
)
3315 struct dentry
*alias
= d_find_alias(inode
);
3317 return alias
?: d_find_any_alias(inode
);
3321 static struct dentry
*shmem_fh_to_dentry(struct super_block
*sb
,
3322 struct fid
*fid
, int fh_len
, int fh_type
)
3324 struct inode
*inode
;
3325 struct dentry
*dentry
= NULL
;
3332 inum
= (inum
<< 32) | fid
->raw
[1];
3334 inode
= ilookup5(sb
, (unsigned long)(inum
+ fid
->raw
[0]),
3335 shmem_match
, fid
->raw
);
3337 dentry
= shmem_find_alias(inode
);
3344 static int shmem_encode_fh(struct inode
*inode
, __u32
*fh
, int *len
,
3345 struct inode
*parent
)
3349 return FILEID_INVALID
;
3352 if (inode_unhashed(inode
)) {
3353 /* Unfortunately insert_inode_hash is not idempotent,
3354 * so as we hash inodes here rather than at creation
3355 * time, we need a lock to ensure we only try
3358 static DEFINE_SPINLOCK(lock
);
3360 if (inode_unhashed(inode
))
3361 __insert_inode_hash(inode
,
3362 inode
->i_ino
+ inode
->i_generation
);
3366 fh
[0] = inode
->i_generation
;
3367 fh
[1] = inode
->i_ino
;
3368 fh
[2] = ((__u64
)inode
->i_ino
) >> 32;
3374 static const struct export_operations shmem_export_ops
= {
3375 .get_parent
= shmem_get_parent
,
3376 .encode_fh
= shmem_encode_fh
,
3377 .fh_to_dentry
= shmem_fh_to_dentry
,
3391 static const struct constant_table shmem_param_enums_huge
[] = {
3392 {"never", SHMEM_HUGE_NEVER
},
3393 {"always", SHMEM_HUGE_ALWAYS
},
3394 {"within_size", SHMEM_HUGE_WITHIN_SIZE
},
3395 {"advise", SHMEM_HUGE_ADVISE
},
3399 const struct fs_parameter_spec shmem_fs_parameters
[] = {
3400 fsparam_u32 ("gid", Opt_gid
),
3401 fsparam_enum ("huge", Opt_huge
, shmem_param_enums_huge
),
3402 fsparam_u32oct("mode", Opt_mode
),
3403 fsparam_string("mpol", Opt_mpol
),
3404 fsparam_string("nr_blocks", Opt_nr_blocks
),
3405 fsparam_string("nr_inodes", Opt_nr_inodes
),
3406 fsparam_string("size", Opt_size
),
3407 fsparam_u32 ("uid", Opt_uid
),
3411 static int shmem_parse_one(struct fs_context
*fc
, struct fs_parameter
*param
)
3413 struct shmem_options
*ctx
= fc
->fs_private
;
3414 struct fs_parse_result result
;
3415 unsigned long long size
;
3419 opt
= fs_parse(fc
, shmem_fs_parameters
, param
, &result
);
3425 size
= memparse(param
->string
, &rest
);
3427 size
<<= PAGE_SHIFT
;
3428 size
*= totalram_pages();
3434 ctx
->blocks
= DIV_ROUND_UP(size
, PAGE_SIZE
);
3435 ctx
->seen
|= SHMEM_SEEN_BLOCKS
;
3438 ctx
->blocks
= memparse(param
->string
, &rest
);
3441 ctx
->seen
|= SHMEM_SEEN_BLOCKS
;
3444 ctx
->inodes
= memparse(param
->string
, &rest
);
3447 ctx
->seen
|= SHMEM_SEEN_INODES
;
3450 ctx
->mode
= result
.uint_32
& 07777;
3453 ctx
->uid
= make_kuid(current_user_ns(), result
.uint_32
);
3454 if (!uid_valid(ctx
->uid
))
3458 ctx
->gid
= make_kgid(current_user_ns(), result
.uint_32
);
3459 if (!gid_valid(ctx
->gid
))
3463 ctx
->huge
= result
.uint_32
;
3464 if (ctx
->huge
!= SHMEM_HUGE_NEVER
&&
3465 !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
3466 has_transparent_hugepage()))
3467 goto unsupported_parameter
;
3468 ctx
->seen
|= SHMEM_SEEN_HUGE
;
3471 if (IS_ENABLED(CONFIG_NUMA
)) {
3472 mpol_put(ctx
->mpol
);
3474 if (mpol_parse_str(param
->string
, &ctx
->mpol
))
3478 goto unsupported_parameter
;
3482 unsupported_parameter
:
3483 return invalfc(fc
, "Unsupported parameter '%s'", param
->key
);
3485 return invalfc(fc
, "Bad value for '%s'", param
->key
);
3488 static int shmem_parse_options(struct fs_context
*fc
, void *data
)
3490 char *options
= data
;
3493 int err
= security_sb_eat_lsm_opts(options
, &fc
->security
);
3498 while (options
!= NULL
) {
3499 char *this_char
= options
;
3502 * NUL-terminate this option: unfortunately,
3503 * mount options form a comma-separated list,
3504 * but mpol's nodelist may also contain commas.
3506 options
= strchr(options
, ',');
3507 if (options
== NULL
)
3510 if (!isdigit(*options
)) {
3516 char *value
= strchr(this_char
,'=');
3522 len
= strlen(value
);
3524 err
= vfs_parse_fs_string(fc
, this_char
, value
, len
);
3533 * Reconfigure a shmem filesystem.
3535 * Note that we disallow change from limited->unlimited blocks/inodes while any
3536 * are in use; but we must separately disallow unlimited->limited, because in
3537 * that case we have no record of how much is already in use.
3539 static int shmem_reconfigure(struct fs_context
*fc
)
3541 struct shmem_options
*ctx
= fc
->fs_private
;
3542 struct shmem_sb_info
*sbinfo
= SHMEM_SB(fc
->root
->d_sb
);
3543 unsigned long inodes
;
3546 spin_lock(&sbinfo
->stat_lock
);
3547 inodes
= sbinfo
->max_inodes
- sbinfo
->free_inodes
;
3548 if ((ctx
->seen
& SHMEM_SEEN_BLOCKS
) && ctx
->blocks
) {
3549 if (!sbinfo
->max_blocks
) {
3550 err
= "Cannot retroactively limit size";
3553 if (percpu_counter_compare(&sbinfo
->used_blocks
,
3555 err
= "Too small a size for current use";
3559 if ((ctx
->seen
& SHMEM_SEEN_INODES
) && ctx
->inodes
) {
3560 if (!sbinfo
->max_inodes
) {
3561 err
= "Cannot retroactively limit inodes";
3564 if (ctx
->inodes
< inodes
) {
3565 err
= "Too few inodes for current use";
3570 if (ctx
->seen
& SHMEM_SEEN_HUGE
)
3571 sbinfo
->huge
= ctx
->huge
;
3572 if (ctx
->seen
& SHMEM_SEEN_BLOCKS
)
3573 sbinfo
->max_blocks
= ctx
->blocks
;
3574 if (ctx
->seen
& SHMEM_SEEN_INODES
) {
3575 sbinfo
->max_inodes
= ctx
->inodes
;
3576 sbinfo
->free_inodes
= ctx
->inodes
- inodes
;
3580 * Preserve previous mempolicy unless mpol remount option was specified.
3583 mpol_put(sbinfo
->mpol
);
3584 sbinfo
->mpol
= ctx
->mpol
; /* transfers initial ref */
3587 spin_unlock(&sbinfo
->stat_lock
);
3590 spin_unlock(&sbinfo
->stat_lock
);
3591 return invalfc(fc
, "%s", err
);
3594 static int shmem_show_options(struct seq_file
*seq
, struct dentry
*root
)
3596 struct shmem_sb_info
*sbinfo
= SHMEM_SB(root
->d_sb
);
3598 if (sbinfo
->max_blocks
!= shmem_default_max_blocks())
3599 seq_printf(seq
, ",size=%luk",
3600 sbinfo
->max_blocks
<< (PAGE_SHIFT
- 10));
3601 if (sbinfo
->max_inodes
!= shmem_default_max_inodes())
3602 seq_printf(seq
, ",nr_inodes=%lu", sbinfo
->max_inodes
);
3603 if (sbinfo
->mode
!= (0777 | S_ISVTX
))
3604 seq_printf(seq
, ",mode=%03ho", sbinfo
->mode
);
3605 if (!uid_eq(sbinfo
->uid
, GLOBAL_ROOT_UID
))
3606 seq_printf(seq
, ",uid=%u",
3607 from_kuid_munged(&init_user_ns
, sbinfo
->uid
));
3608 if (!gid_eq(sbinfo
->gid
, GLOBAL_ROOT_GID
))
3609 seq_printf(seq
, ",gid=%u",
3610 from_kgid_munged(&init_user_ns
, sbinfo
->gid
));
3611 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3612 /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
3614 seq_printf(seq
, ",huge=%s", shmem_format_huge(sbinfo
->huge
));
3616 shmem_show_mpol(seq
, sbinfo
->mpol
);
3620 #endif /* CONFIG_TMPFS */
3622 static void shmem_put_super(struct super_block
*sb
)
3624 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
3626 percpu_counter_destroy(&sbinfo
->used_blocks
);
3627 mpol_put(sbinfo
->mpol
);
3629 sb
->s_fs_info
= NULL
;
3632 static int shmem_fill_super(struct super_block
*sb
, struct fs_context
*fc
)
3634 struct shmem_options
*ctx
= fc
->fs_private
;
3635 struct inode
*inode
;
3636 struct shmem_sb_info
*sbinfo
;
3639 /* Round up to L1_CACHE_BYTES to resist false sharing */
3640 sbinfo
= kzalloc(max((int)sizeof(struct shmem_sb_info
),
3641 L1_CACHE_BYTES
), GFP_KERNEL
);
3645 sb
->s_fs_info
= sbinfo
;
3649 * Per default we only allow half of the physical ram per
3650 * tmpfs instance, limiting inodes to one per page of lowmem;
3651 * but the internal instance is left unlimited.
3653 if (!(sb
->s_flags
& SB_KERNMOUNT
)) {
3654 if (!(ctx
->seen
& SHMEM_SEEN_BLOCKS
))
3655 ctx
->blocks
= shmem_default_max_blocks();
3656 if (!(ctx
->seen
& SHMEM_SEEN_INODES
))
3657 ctx
->inodes
= shmem_default_max_inodes();
3659 sb
->s_flags
|= SB_NOUSER
;
3661 sb
->s_export_op
= &shmem_export_ops
;
3662 sb
->s_flags
|= SB_NOSEC
;
3664 sb
->s_flags
|= SB_NOUSER
;
3666 sbinfo
->max_blocks
= ctx
->blocks
;
3667 sbinfo
->free_inodes
= sbinfo
->max_inodes
= ctx
->inodes
;
3668 sbinfo
->uid
= ctx
->uid
;
3669 sbinfo
->gid
= ctx
->gid
;
3670 sbinfo
->mode
= ctx
->mode
;
3671 sbinfo
->huge
= ctx
->huge
;
3672 sbinfo
->mpol
= ctx
->mpol
;
3675 spin_lock_init(&sbinfo
->stat_lock
);
3676 if (percpu_counter_init(&sbinfo
->used_blocks
, 0, GFP_KERNEL
))
3678 spin_lock_init(&sbinfo
->shrinklist_lock
);
3679 INIT_LIST_HEAD(&sbinfo
->shrinklist
);
3681 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
3682 sb
->s_blocksize
= PAGE_SIZE
;
3683 sb
->s_blocksize_bits
= PAGE_SHIFT
;
3684 sb
->s_magic
= TMPFS_MAGIC
;
3685 sb
->s_op
= &shmem_ops
;
3686 sb
->s_time_gran
= 1;
3687 #ifdef CONFIG_TMPFS_XATTR
3688 sb
->s_xattr
= shmem_xattr_handlers
;
3690 #ifdef CONFIG_TMPFS_POSIX_ACL
3691 sb
->s_flags
|= SB_POSIXACL
;
3693 uuid_gen(&sb
->s_uuid
);
3695 inode
= shmem_get_inode(sb
, NULL
, S_IFDIR
| sbinfo
->mode
, 0, VM_NORESERVE
);
3698 inode
->i_uid
= sbinfo
->uid
;
3699 inode
->i_gid
= sbinfo
->gid
;
3700 sb
->s_root
= d_make_root(inode
);
3706 shmem_put_super(sb
);
3710 static int shmem_get_tree(struct fs_context
*fc
)
3712 return get_tree_nodev(fc
, shmem_fill_super
);
3715 static void shmem_free_fc(struct fs_context
*fc
)
3717 struct shmem_options
*ctx
= fc
->fs_private
;
3720 mpol_put(ctx
->mpol
);
3725 static const struct fs_context_operations shmem_fs_context_ops
= {
3726 .free
= shmem_free_fc
,
3727 .get_tree
= shmem_get_tree
,
3729 .parse_monolithic
= shmem_parse_options
,
3730 .parse_param
= shmem_parse_one
,
3731 .reconfigure
= shmem_reconfigure
,
3735 static struct kmem_cache
*shmem_inode_cachep
;
3737 static struct inode
*shmem_alloc_inode(struct super_block
*sb
)
3739 struct shmem_inode_info
*info
;
3740 info
= kmem_cache_alloc(shmem_inode_cachep
, GFP_KERNEL
);
3743 return &info
->vfs_inode
;
3746 static void shmem_free_in_core_inode(struct inode
*inode
)
3748 if (S_ISLNK(inode
->i_mode
))
3749 kfree(inode
->i_link
);
3750 kmem_cache_free(shmem_inode_cachep
, SHMEM_I(inode
));
3753 static void shmem_destroy_inode(struct inode
*inode
)
3755 if (S_ISREG(inode
->i_mode
))
3756 mpol_free_shared_policy(&SHMEM_I(inode
)->policy
);
3759 static void shmem_init_inode(void *foo
)
3761 struct shmem_inode_info
*info
= foo
;
3762 inode_init_once(&info
->vfs_inode
);
3765 static void shmem_init_inodecache(void)
3767 shmem_inode_cachep
= kmem_cache_create("shmem_inode_cache",
3768 sizeof(struct shmem_inode_info
),
3769 0, SLAB_PANIC
|SLAB_ACCOUNT
, shmem_init_inode
);
3772 static void shmem_destroy_inodecache(void)
3774 kmem_cache_destroy(shmem_inode_cachep
);
3777 static const struct address_space_operations shmem_aops
= {
3778 .writepage
= shmem_writepage
,
3779 .set_page_dirty
= __set_page_dirty_no_writeback
,
3781 .write_begin
= shmem_write_begin
,
3782 .write_end
= shmem_write_end
,
3784 #ifdef CONFIG_MIGRATION
3785 .migratepage
= migrate_page
,
3787 .error_remove_page
= generic_error_remove_page
,
3790 static const struct file_operations shmem_file_operations
= {
3792 .get_unmapped_area
= shmem_get_unmapped_area
,
3794 .llseek
= shmem_file_llseek
,
3795 .read_iter
= shmem_file_read_iter
,
3796 .write_iter
= generic_file_write_iter
,
3797 .fsync
= noop_fsync
,
3798 .splice_read
= generic_file_splice_read
,
3799 .splice_write
= iter_file_splice_write
,
3800 .fallocate
= shmem_fallocate
,
3804 static const struct inode_operations shmem_inode_operations
= {
3805 .getattr
= shmem_getattr
,
3806 .setattr
= shmem_setattr
,
3807 #ifdef CONFIG_TMPFS_XATTR
3808 .listxattr
= shmem_listxattr
,
3809 .set_acl
= simple_set_acl
,
3813 static const struct inode_operations shmem_dir_inode_operations
= {
3815 .create
= shmem_create
,
3816 .lookup
= simple_lookup
,
3818 .unlink
= shmem_unlink
,
3819 .symlink
= shmem_symlink
,
3820 .mkdir
= shmem_mkdir
,
3821 .rmdir
= shmem_rmdir
,
3822 .mknod
= shmem_mknod
,
3823 .rename
= shmem_rename2
,
3824 .tmpfile
= shmem_tmpfile
,
3826 #ifdef CONFIG_TMPFS_XATTR
3827 .listxattr
= shmem_listxattr
,
3829 #ifdef CONFIG_TMPFS_POSIX_ACL
3830 .setattr
= shmem_setattr
,
3831 .set_acl
= simple_set_acl
,
3835 static const struct inode_operations shmem_special_inode_operations
= {
3836 #ifdef CONFIG_TMPFS_XATTR
3837 .listxattr
= shmem_listxattr
,
3839 #ifdef CONFIG_TMPFS_POSIX_ACL
3840 .setattr
= shmem_setattr
,
3841 .set_acl
= simple_set_acl
,
3845 static const struct super_operations shmem_ops
= {
3846 .alloc_inode
= shmem_alloc_inode
,
3847 .free_inode
= shmem_free_in_core_inode
,
3848 .destroy_inode
= shmem_destroy_inode
,
3850 .statfs
= shmem_statfs
,
3851 .show_options
= shmem_show_options
,
3853 .evict_inode
= shmem_evict_inode
,
3854 .drop_inode
= generic_delete_inode
,
3855 .put_super
= shmem_put_super
,
3856 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3857 .nr_cached_objects
= shmem_unused_huge_count
,
3858 .free_cached_objects
= shmem_unused_huge_scan
,
3862 static const struct vm_operations_struct shmem_vm_ops
= {
3863 .fault
= shmem_fault
,
3864 .map_pages
= filemap_map_pages
,
3866 .set_policy
= shmem_set_policy
,
3867 .get_policy
= shmem_get_policy
,
3871 int shmem_init_fs_context(struct fs_context
*fc
)
3873 struct shmem_options
*ctx
;
3875 ctx
= kzalloc(sizeof(struct shmem_options
), GFP_KERNEL
);
3879 ctx
->mode
= 0777 | S_ISVTX
;
3880 ctx
->uid
= current_fsuid();
3881 ctx
->gid
= current_fsgid();
3883 fc
->fs_private
= ctx
;
3884 fc
->ops
= &shmem_fs_context_ops
;
3888 static struct file_system_type shmem_fs_type
= {
3889 .owner
= THIS_MODULE
,
3891 .init_fs_context
= shmem_init_fs_context
,
3893 .parameters
= shmem_fs_parameters
,
3895 .kill_sb
= kill_litter_super
,
3896 .fs_flags
= FS_USERNS_MOUNT
,
3899 int __init
shmem_init(void)
3903 shmem_init_inodecache();
3905 error
= register_filesystem(&shmem_fs_type
);
3907 pr_err("Could not register tmpfs\n");
3911 shm_mnt
= kern_mount(&shmem_fs_type
);
3912 if (IS_ERR(shm_mnt
)) {
3913 error
= PTR_ERR(shm_mnt
);
3914 pr_err("Could not kern_mount tmpfs\n");
3918 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3919 if (has_transparent_hugepage() && shmem_huge
> SHMEM_HUGE_DENY
)
3920 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3922 shmem_huge
= 0; /* just in case it was patched */
3927 unregister_filesystem(&shmem_fs_type
);
3929 shmem_destroy_inodecache();
3930 shm_mnt
= ERR_PTR(error
);
3934 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
3935 static ssize_t
shmem_enabled_show(struct kobject
*kobj
,
3936 struct kobj_attribute
*attr
, char *buf
)
3938 static const int values
[] = {
3940 SHMEM_HUGE_WITHIN_SIZE
,
3948 for (i
= 0, count
= 0; i
< ARRAY_SIZE(values
); i
++) {
3949 const char *fmt
= shmem_huge
== values
[i
] ? "[%s] " : "%s ";
3951 count
+= sprintf(buf
+ count
, fmt
,
3952 shmem_format_huge(values
[i
]));
3954 buf
[count
- 1] = '\n';
3958 static ssize_t
shmem_enabled_store(struct kobject
*kobj
,
3959 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
3964 if (count
+ 1 > sizeof(tmp
))
3966 memcpy(tmp
, buf
, count
);
3968 if (count
&& tmp
[count
- 1] == '\n')
3969 tmp
[count
- 1] = '\0';
3971 huge
= shmem_parse_huge(tmp
);
3972 if (huge
== -EINVAL
)
3974 if (!has_transparent_hugepage() &&
3975 huge
!= SHMEM_HUGE_NEVER
&& huge
!= SHMEM_HUGE_DENY
)
3979 if (shmem_huge
> SHMEM_HUGE_DENY
)
3980 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3984 struct kobj_attribute shmem_enabled_attr
=
3985 __ATTR(shmem_enabled
, 0644, shmem_enabled_show
, shmem_enabled_store
);
3986 #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */
3988 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3989 bool shmem_huge_enabled(struct vm_area_struct
*vma
)
3991 struct inode
*inode
= file_inode(vma
->vm_file
);
3992 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
3996 if ((vma
->vm_flags
& VM_NOHUGEPAGE
) ||
3997 test_bit(MMF_DISABLE_THP
, &vma
->vm_mm
->flags
))
3999 if (shmem_huge
== SHMEM_HUGE_FORCE
)
4001 if (shmem_huge
== SHMEM_HUGE_DENY
)
4003 switch (sbinfo
->huge
) {
4004 case SHMEM_HUGE_NEVER
:
4006 case SHMEM_HUGE_ALWAYS
:
4008 case SHMEM_HUGE_WITHIN_SIZE
:
4009 off
= round_up(vma
->vm_pgoff
, HPAGE_PMD_NR
);
4010 i_size
= round_up(i_size_read(inode
), PAGE_SIZE
);
4011 if (i_size
>= HPAGE_PMD_SIZE
&&
4012 i_size
>> PAGE_SHIFT
>= off
)
4015 case SHMEM_HUGE_ADVISE
:
4016 /* TODO: implement fadvise() hints */
4017 return (vma
->vm_flags
& VM_HUGEPAGE
);
4023 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
4025 #else /* !CONFIG_SHMEM */
4028 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
4030 * This is intended for small system where the benefits of the full
4031 * shmem code (swap-backed and resource-limited) are outweighed by
4032 * their complexity. On systems without swap this code should be
4033 * effectively equivalent, but much lighter weight.
4036 static struct file_system_type shmem_fs_type
= {
4038 .init_fs_context
= ramfs_init_fs_context
,
4039 .parameters
= ramfs_fs_parameters
,
4040 .kill_sb
= kill_litter_super
,
4041 .fs_flags
= FS_USERNS_MOUNT
,
4044 int __init
shmem_init(void)
4046 BUG_ON(register_filesystem(&shmem_fs_type
) != 0);
4048 shm_mnt
= kern_mount(&shmem_fs_type
);
4049 BUG_ON(IS_ERR(shm_mnt
));
4054 int shmem_unuse(unsigned int type
, bool frontswap
,
4055 unsigned long *fs_pages_to_unuse
)
4060 int shmem_lock(struct file
*file
, int lock
, struct user_struct
*user
)
4065 void shmem_unlock_mapping(struct address_space
*mapping
)
4070 unsigned long shmem_get_unmapped_area(struct file
*file
,
4071 unsigned long addr
, unsigned long len
,
4072 unsigned long pgoff
, unsigned long flags
)
4074 return current
->mm
->get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
4078 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
4080 truncate_inode_pages_range(inode
->i_mapping
, lstart
, lend
);
4082 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
4084 #define shmem_vm_ops generic_file_vm_ops
4085 #define shmem_file_operations ramfs_file_operations
4086 #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
4087 #define shmem_acct_size(flags, size) 0
4088 #define shmem_unacct_size(flags, size) do {} while (0)
4090 #endif /* CONFIG_SHMEM */
4094 static struct file
*__shmem_file_setup(struct vfsmount
*mnt
, const char *name
, loff_t size
,
4095 unsigned long flags
, unsigned int i_flags
)
4097 struct inode
*inode
;
4101 return ERR_CAST(mnt
);
4103 if (size
< 0 || size
> MAX_LFS_FILESIZE
)
4104 return ERR_PTR(-EINVAL
);
4106 if (shmem_acct_size(flags
, size
))
4107 return ERR_PTR(-ENOMEM
);
4109 inode
= shmem_get_inode(mnt
->mnt_sb
, NULL
, S_IFREG
| S_IRWXUGO
, 0,
4111 if (unlikely(!inode
)) {
4112 shmem_unacct_size(flags
, size
);
4113 return ERR_PTR(-ENOSPC
);
4115 inode
->i_flags
|= i_flags
;
4116 inode
->i_size
= size
;
4117 clear_nlink(inode
); /* It is unlinked */
4118 res
= ERR_PTR(ramfs_nommu_expand_for_mapping(inode
, size
));
4120 res
= alloc_file_pseudo(inode
, mnt
, name
, O_RDWR
,
4121 &shmem_file_operations
);
4128 * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
4129 * kernel internal. There will be NO LSM permission checks against the
4130 * underlying inode. So users of this interface must do LSM checks at a
4131 * higher layer. The users are the big_key and shm implementations. LSM
4132 * checks are provided at the key or shm level rather than the inode.
4133 * @name: name for dentry (to be seen in /proc/<pid>/maps
4134 * @size: size to be set for the file
4135 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4137 struct file
*shmem_kernel_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4139 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, S_PRIVATE
);
4143 * shmem_file_setup - get an unlinked file living in tmpfs
4144 * @name: name for dentry (to be seen in /proc/<pid>/maps
4145 * @size: size to be set for the file
4146 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4148 struct file
*shmem_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4150 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, 0);
4152 EXPORT_SYMBOL_GPL(shmem_file_setup
);
4155 * shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
4156 * @mnt: the tmpfs mount where the file will be created
4157 * @name: name for dentry (to be seen in /proc/<pid>/maps
4158 * @size: size to be set for the file
4159 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4161 struct file
*shmem_file_setup_with_mnt(struct vfsmount
*mnt
, const char *name
,
4162 loff_t size
, unsigned long flags
)
4164 return __shmem_file_setup(mnt
, name
, size
, flags
, 0);
4166 EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt
);
4169 * shmem_zero_setup - setup a shared anonymous mapping
4170 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
4172 int shmem_zero_setup(struct vm_area_struct
*vma
)
4175 loff_t size
= vma
->vm_end
- vma
->vm_start
;
4178 * Cloning a new file under mmap_sem leads to a lock ordering conflict
4179 * between XFS directory reading and selinux: since this file is only
4180 * accessible to the user through its mapping, use S_PRIVATE flag to
4181 * bypass file security, in the same way as shmem_kernel_file_setup().
4183 file
= shmem_kernel_file_setup("dev/zero", size
, vma
->vm_flags
);
4185 return PTR_ERR(file
);
4189 vma
->vm_file
= file
;
4190 vma
->vm_ops
= &shmem_vm_ops
;
4192 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
4193 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
4194 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
4195 khugepaged_enter(vma
, vma
->vm_flags
);
4202 * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
4203 * @mapping: the page's address_space
4204 * @index: the page index
4205 * @gfp: the page allocator flags to use if allocating
4207 * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
4208 * with any new page allocations done using the specified allocation flags.
4209 * But read_cache_page_gfp() uses the ->readpage() method: which does not
4210 * suit tmpfs, since it may have pages in swapcache, and needs to find those
4211 * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
4213 * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
4214 * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
4216 struct page
*shmem_read_mapping_page_gfp(struct address_space
*mapping
,
4217 pgoff_t index
, gfp_t gfp
)
4220 struct inode
*inode
= mapping
->host
;
4224 BUG_ON(mapping
->a_ops
!= &shmem_aops
);
4225 error
= shmem_getpage_gfp(inode
, index
, &page
, SGP_CACHE
,
4226 gfp
, NULL
, NULL
, NULL
);
4228 page
= ERR_PTR(error
);
4234 * The tiny !SHMEM case uses ramfs without swap
4236 return read_cache_page_gfp(mapping
, index
, gfp
);
4239 EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp
);